تدریس

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تدریس تکنیکهای زبان ت پنجشنبه ۲۲ شهریور ۰۳ | ۲۰:۰۸ ۱۰ بازديد
awake
be
beat
begin
bite
blow
break
bring
build
buy
catch
choose
come
cost
cut
do
deal
dig
dream
draw
drink
drive
eat
fall
feed
feel
fight
find
fly
forget
forgive
freeze
get
give
go
grow
hang
have
hear
hide
hit
hold
hurt
keep
know
lay
lead
leave
lend
let

gr

تدریس تکنیکهای زبان ت پنجشنبه ۲۲ شهریور ۰۳ | ۲۰:۰۰ ۷ بازديد
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
C.P.U.
Sarita,Vikki,SRCC,DU E-RESOURCE 55
 
 
MEMORY
Memory: It is a storage device used to store information in
computers. The semiconductor memory is organized into
memory cells or bistable flip-flops, each storing one
binary bit (0 or 1). The memory cells are grouped into
words of fix word length, for example 1, 2, 4, 8, 16, 32, 64
or 128 bit. Each word can be accessed by a binary address
of N bit, making it possible to store 2 raised by N words in
the memory
Sarita,Vikki,SRCC,DU E-RESOURCE 56
 
 
What are bits, bytes, and other units of measure
for digital information?
A bit is a binary digit, the smallest increment of data on a
computer. A bit can hold only one of two values: 0 or 1,
corresponding to the electrical values of off or on,
respectively.
Because bits are so small, you rarely work with information
one bit at a time. Bits are usually assembled into a group of
eight to form a byte. A byte contains enough information to
store a single ASCII character, like “k” (maybe 00101101).
Sarita,Vikki,SRCC,DU E-RESOURCE 57
 
 
So in computer jargon, the following
memory units are used:
Unit
1 bit 1 nibble 1
Byte
1 Kilobyte (KB)
1 Megabyte
(MB) 1 Gigabyte
(GB)
1 Terabyte (TB)
1 Petabyte (PB)
Sarita,Vikki,SRCC,DU
Equivalent
0 or 1
a group of 4 bits a
group of 8 bits 103
(i.e.,1024 bytes) 106
bytes 109 bytes 1012
bytes 1015 bytes
E-RESOURCE
 
 
There are different types of memories
in computers:-
Registers: Small memory, internal to processor, where actual
processing is done.
Cache Memory: Catches some of content of main memory
which current in use of the processor.
Main Memory (RAM/ROM): Large memory which is fast
but not as internal Processor memory.
All the above memories are volatile memories
because the stored information is lost when the power is
removed from the system.
Sarita,Vikki,SRCC,DU E-RESOURCE 59
 
 
RAM; Random Access Memory. It is volatile memory.
It allows both read/write operations.
ROM: Read Only Memory. It is non-volatile memory.
It allows only read operations.
Random Access Memory (RAM) is a form of
computer data storage. Today, it takes the form of integrated
circuits that allow stored data to be accessed in any order.
Other memory devices (magnetic tapes, floppy discs, CDs and
DVDs) can access the storage data only in a predetermined
order, because of mechanical design limitations. The two
main forms of modern RAM are Static RAM (SRAM) and
Dynamic RAM (DRAM).
Sarita,Vikki,SRCC,DU E-RESOURCE 60
 
 
R.A.M.
Sarita,Vikki,SRCC,DU E-RESOURCE 61
 
 
SECONDARY MEMORY
Secondary Memory; Very large memory. It is a nonvolatile
permanent memory.
• Eg; Magnetic disk (Hard / Floppy) memory, Magnetic Tape
memory etc.,
HDD (Hard Disk Drive): It is a mechanism which drives
Hard Disks to rotate and controls the flow of data between
hard disk and computer. Both hard disk and hard disk
drive comes in a single unit, it is permanently fixed in a
system unit.
Sarita,Vikki,SRCC,DU E-RESOURCE 62
 
 
A Hard Disk Drive (HDD) is device for storing and
retrieving digital information, primarily computer data. It
consists of one or more rigid (hence "hard") rapidly
rotating discs (platters usually rotating at 7,200 RPM)
coated with magnetic material, and with magnetic heads to
write data to the surfaces and read it from them.
Magnetic recording A hard disk drive records data
by magnetizing a thin film of ferromagnetic material on a
disk. Sequential changes in the direction of magnetization
represent binary data bits. The data is read from the disk
by detecting the transitions in magnetization

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تدریس تکنیکهای زبان ت پنجشنبه ۲۲ شهریور ۰۳ | ۱۹:۵۹ ۷ بازديد
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Module 3 - Values and attitudes of police officersRecommended Readings for Facilitators
1. Positive policing values
2. Importance of education for personal values
College of Policing. “Code of Ethics: A Code of Practice for the Principles and Standards of Professional Beha-
viour for the Policing Profession of England and Wales.” London: College of Policing, 2014: 3.
OSCE. “Police Ethics for Preserving Personal and Professional Integrity.” Belgrade: OSCE, 2014.
Council of Europe. “The European Code of Police Ethics.” Strasbourg: Council of Europe, 2002.
“Article 23. Police personnel shall be able to demonstrate sound judgment, an open attitude, maturity, fairness, communi-
cation skills and, where appropriate, leadership and management skills. Moreover, they shall possess a good understan-
ding of social, cultural and community issues.”
“2.1 Doing the right thing in the right way
2.1.1
Every person working for the police service must work honestly and ethically. The public expect the police to do the right
thing in the right way. Basing decisions and actions on a set of policing principles will help to achieve this.
2.1.3
The policing principles reflect the personal beliefs and aspirations that in turn serve to guide behaviour and shape the
policing culture. The combination of principles and standards of behaviour encourages consistency between what people
believe in and aspire to, and what they do.
Policing Principles:
• Accountability: You are answerable for your decisions, actions, and omissions.
• Fairness: You treat people fairly.
• Honesty: You are truthful and trustworthy.
• Integrity: You always do the right thing.
• Leadership: You lead by good example.
• Objectivity: You make choices on evidence and your best professional judgment.
• Openness: You are open and transparent in your actions and decisions.
• Respect: You treat everyone with respect.
• Selflessness: You act in the public interest.”
“Each person in his or her life continually values various elements and manifestations of reality, both in private and social
life. It has already been said that a human being develops into a moral personality through education. The result of this
process is the creation of moral character.
The formed moral character implies a durable disposition acquired as a habit through the long-lasting process of education.
The basic valuation method is the classification of elements in the following notions:
• true and false;
• good and evil;
• beautiful and ugly;
• just and unjust;
• sacred (ecclesiastical/religious) and secular (non-ecclesiastical/non-religious), etc.”
 
 
Module 3 - Values and attitudes of police officers4. Influence of attitudes on behaviour
Gilmartin, Kevin M. and John J. Harris. “Law Enforcement Ethics… The Continuum of Compromise.” Police
Chief Magazine 65, no. 1 (1998): 25-28.
“Officers frequently develop a perceived sense of victimization over time. Officers typically begin their careers as enthu-
siastic, highly motivated people. However, when these young officers over-invest in and over-identify with their professional
role they will develop a sense of singular-identity based on their job and an increased sense of victimization. At greatest
risk are officers whose jobs literally become their lives. For them, ‘I am a cop.’ is not just a cliché but rather a way of life.
Over-identification and over-investment causes people to link their sense of self to their police role . . . a role they do not
control. While this builds camaraderie, it can also cause officers to eventually hate and resent the job they once loved.
While officers have absolute control over their own integrity and professionalism, the rest of their police role is controlled
by someone else. Department rules, procedures, policies, equipment, budget allocations, assignments, dress codes, and
many other day-to-day and long-term activities are controlled by the chief, commanders, supervisors, prosecuting attor-
neys, the criminal justice system, laws, the courts, politicians, etc. Officers who over-identify with the job soon experience
a loss of control over other aspects of their lives. Professional over-investment, coupled with a loss of personal control puts
officers at serious risk . . . a risk that in some ways is more dangerous than the physical risks they face on the street. ‘It
doesn’t matter how guilty you are, but how slick your lawyer is,’ can become the officers cynical yet reality-based percep-
tion of the legal system. These realities combine with over-investment to develop an ‘Us versus them’ perception in terms
of how officers see the world.
The physical risks that officers are exposed to each day require them to see the world as potentially lethal. To survive, they
have to develop a ‘hypervigilant’ (Gilmartin, 1984) mind-set. Hypervigilance coupled with over-investment leads officers
to believe the only person you can really trust is another cop . . . a ‘real cop’ that is, not some ‘pencil-neck in the adminis-
tration’. While officers first become alienated from the public, they can soon distance themselves from the criminal justice
system and finally from their own department administration. ‘I can handle the morons on the street, I just can’t handle the
morons in the administration,’ is often heard among officers. It is ironic how quickly idealism and trust in the administration
can change . . . often times even before the first set of uniforms wears out. As a sense of perceived victimization intensifies,
officers become more distrusting and resentful of anyone who controls their job role. At this point, without any conscious
awareness and certainly without any unethical intent, unsuspecting officers can begin a journey down the continuum of
compromise.
Recommended Readings for Facilitators
3. Organisational values
Wasserman, Robert and Mark H. Moore. “Values in Policing.” Perspectives on Policing, 8 (1988): 1-7.
“This paper explores the role that the explicit statement of police values can have on the pursuit of excellence within police
departments. Values are the beliefs that guide an organization and the behavior of its employees. The most important be-
liefs are those that set forth the ultimate purposes of the organization. They provide the organization with its raison d’etre
for outsiders and insiders alike and justify the continuing investment in the organization’s enterprise. . . .
All organizations have values. One can see these values expressed through the actions of the organization -the things that
are taken seriously and the things that are rejected as irrelevant, inappropriate, or dangerous. Jokes, solemn understan-
dings, and internal explanations for actions also express values.
Police departments are powerfully influenced by their values. The problem is that police departments, like many organiza-
tions, are guided by implicit values that are often at odds with explicit values. This breeds confusion, distrust, and cynicism
rather than clarity, commitment, and high morale. . . .
Almost as bad, the explicit values articulated by some police organizations are unsuited to the challenges confronting
today’s police departments. Finally, there is a reluctance from the part of some police executives to rely on explicit state-
ments of values as an important management tool for enhancing the performance of their organizations. Still, some police
executives are working towards superior police performance by articulating a new set of values, and by using these as a
primary management tool. . . . Values play this important role for several reasons. . . . This helps employees make proper
decisions and use their discretion with confidence that they are contributing to rather than detracting from organizational
performance. That means that the necessity for strong control is lessened. . . .
[In modern policing], values are no longer hidden, but serve as the basis for citizen understanding of the police function,
judgments of police success, and employee understanding of what the police agency seeks to achieve.”
 
 
Module 3 - Values and attitudes of police officersFurther readings
• Cobut, Eric. “Chapter 2: Section 2: Why are Values, Rules and Behaviour Important in the Struggle against Corrup-
tion?” In Toolkit on Police Integrity, edited by Pierre Aepli. Geneva: DCAF, 2012. http://www.dcaf.ch/Publications/Toolk-
it-on-Police-Integrity
• Johnson, Terrance and Raymond W Cox III. “Police Ethics: Organizational Implications.” Public Integrity 7, no. 1 (2004):
67-79.
• OSCE. “Police Ethics for Preserving Personal and Professional Integrity.” Belgrade: OSCE, 2014
• Raines, Julie. “Chapter 9: In Law Enforcement we trust: Ethical Attitudes and Behaviors of Law Enforcement Officers
and Supervisors.” In Ethics in Policing: Misconduct and Integrity. Sudbury: Jones and Bartlett, 2011.
• Wasserman, Robert and Mark H. Moore. “Values in Policing.” Perspectives on Policing 8 (1988).http://www.public-
safety.gc.ca/cnt/cntrng-crm/plcng/cnmcs-plcng/rsrch-prtl/shwttls-eng.aspx?d=PS&i=85165633
When officers (or anyone for that matter) feel victimized, in their own mind they can rationalize and justify behaviors they
may not normally engage in. [For instance,] officers [may] rationalize and justify not doing things they are responsible for
doing. At this point, officers can feel quite justified in not doing things that, from their own perspective, appear to ‘even the
score’. ‘If they (whomever it may be) don’t care about us, why should we care about them.’ Acts of omission can include
selective non-productivity (ignoring traffic violations or certain criminal violations, etc.), ‘not seeing’ or avoiding on-sight ac-
tivity, superficial investigations, omitting paperwork, lack of follow up, doing enough to just ‘get by’and many other activities
which officers can easily omit. ‘You will never get in trouble for the stop you don’t make!’ typifies the mind-set of officers
during this stage. This results in decreased productivity and produces passive resistance to organizational mandates.”
 
 
Module 3 - Values and attitudes of police officersFor police officers in professional life:
• performing their duties professionally
• performing their duties honestly
• building self-confidence and self-respect in work
• gaining respect from colleagues
• gaining respect from superiors
• gaining respect from citizens
• being an example for other colleagues
• possibility of being rewarded for work
• career building opportunities
• avoiding disciplinary or criminal procedures
• avoiding bitterness and burnout
• getting satisfaction from their job
For police officers in personal life:
• building self-confidence
• not bringing work home
• getting personal satisfaction and maintaining a good self-image
• transferring that satisfaction to the family
• being respected by family members and friends
• avoiding embarassment, shame and disgrace of officer and his/her friends and family because of scandals in media
or justice system
Why is police integrity important for you?
Participant’s Handbook
Values:
Integrity has a lot to do with values, since we defined it as the alignment of behaviour with moral values. Your own values
are crucial to help you make the right choices in difficult situations.
However, the organisation should also clearly define its values, including in a code of ethics, and you must be aware of
them.
Some key policing values include public service, impartiality, fairness, and professionalism.
Attitudes:
An attitude is a positive or negative evaluation of people, objects, events, activities, ideas, or just about anything in the
environment. An attitude can be conscious or unconscious.
People’s attitudes affect their ethical behavior. For instance, consistently going to work with bitter, negative attitudes about
yourself, your job, your interpersonal relationships, or your life in general is a pretty accurate predictor that unethical ac-
tions and decisions will follow.
Often, individual attitudes are influenced by the culture of the organisation. But you should keep in mind that it is the addi-
tion of your personal values, attitudes and behavior that shape group behavior, culture and sub-cultures in the organization.
By displaying positive attitudes, you can be a role model in the organisation and contribute to a culture of integrity.
 
 
Module 3 - Values and attitudes of police officersFor police organisation:
• reducing number of disciplinary and criminal acts
• reducing costs of judicial and other procedures
• developing organisational culture
• increasing operational efficiency and effectiveness
• increasing employee satisfaction
• maintaining the image of a police that serves and protects citizens
• possibility of further improvement and development of organisation
• gaining the trust of citizens
 
 
Module 4
Police integrity legal and regulatory
framework
 
 
1Module 4
Police integrity legal and regulatory framework
Module aim:
Time: 55 minutes
Required material: Extracts of relevant legislation and regulations
Help the participants identify and analyse international, national, and internal laws, rules, and regulations
relevant to police integrity.
Learning objectives:
By the end of this session the participants will be able to:
1. List international, national, and internal laws, rules, and regulations relevant to police integrity.
2. Identify the relevant parts from the listed documents and their implications in practice.
Short description of the module:
This module aims to clarify the legal basis of integrity and is organised around the analysis and presentation
of laws related to integrity by small groups of participants. This module requires good preparation by the faci-
litators, who must select the relevant laws and chapters of laws.
This module requires good preparation by the facilitators who must select the relevant national laws and
chapters of laws and regulations on police integrity.
Content Method/action Handouts/aids
Introduction1
Your country’s legal
framework on integrity
Brainstorming
Group activity
Handout 1
All relevant national laws
and regulations related
to integrity selected
by facilitators
2
5’
40’
Conclusion Plenary discussion3 10’
Presentation
 
 
2Module 4 - Police integrity legal and regulatory framework
WHAT - Brief description of the content of the module
► State the focus of the module:
This module is about the international and national laws, regulations, and codes that define and regulate
police integrity and its components.
WHAT FOR - Objectives of the module
► Present the objectives of the module.
HOW - Sequence of the module
► Explain the sequence of the module.
WHY - Relevance of the module
► Explain the relevance of this module, for instance by saying:
Police integrity and its components (definitions and prohibition of various types of misconduct, vision,
mission and values of the police etc.) are often spread over many legal documents, and you might not
always have a very clear idea of their actual content. This module will remind you the legal foundations
of integrity.
Personal notes
1. Introduction5’
 
 
3Module 4 - Police integrity legal and regulatory framework
2. Your country’s legal framework on
integrity
3. Conclusion
40’
5’
► Conduct brainstorming with the whole group around the following questions:
► Summarise the key points of discussion.
► Re-emphasise the key messages of the module.
► Divide the participants into 3-6 groups.
► Distribute to each group one of the major laws or codes regulating police integrity for your country.
► Give the participants 15 minutes to read the law that has been distributed to them, analyse it in relation to
integrity within their group and get ready to present their analysis to the other groups.
► Instruct them to search for:
• Lists, explanations, and definitions of prohibited and prescribed conduct for police officers;
• Values of the police;
• Any other important points.
► Instruct them to also reflect on the following questions:
► Tell each group to present these key points to their colleagues in 5 minutes.
• What international and national legal documents regulate components of police integrity?
• Do you know what is in each of them that relates to integrity?
Notes:
• You might want to include the United Nations Code of Conduct for Law Enforcement Officials (Handout 1),
extracts of the European Code of Police Ethics (Handout 2), the national law on police, the Police Code of
Conduct and the Code of Police Ethics if they exist in your country, as a minimum.
• Try to give each group approximately the same number of pages. In long laws, give only chapters that are
relevant, or split chapters among groups.
• If your country has so many relevant laws that they cannot be all distributed to a group, prepare a short
summary of those that are not distributed to any group

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تدریس تکنیکهای زبان ت پنجشنبه ۲۲ شهریور ۰۳ | ۱۹:۵۶ ۸ بازديد
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
for others however abundant the money may be.” There are real distri-
butional effects as monetary phenomena work their way through the
economy, just as “a river which runs and winds about in its bed will not
flow with double the speed when the amount of water is doubled.”32
Cantillon’s work was followed in the nineteenth century by John E.
Cairnes and in the twentieth by John Maynard Keynes.33 Keynes, in his
Treatise on Money, followed Cantillon and Cairnes with his argument
that changes in purchasing power that result from monetary contrac-
tions or expansions are “not spread evenly or proportionately over the
various buyers.” The “new distribution of purchasing power” will have
“social and economic consequences” that “may have a fairly large lasting
effect on relative price levels.” Once again, the argument here is not
that monetary disturbances affect aggregate output; rather, it empha-
sizes the consequences of monetary phenomena even in the absence of
such effects. “The fact that monetary changes do not affect all prices in
the same way, to the same degree, or at the same time, is what makes
them significant.”34
Ironically, it was subsequent work by Keynes that led to the atrophy
of this line of inquiry. In The General Theory (1936), which dominated
the profession for a generation and ushered in the era of modern
macroeconomics, Keynes shifted his emphasis away from monetary in-
fluences. The vigorous monetarist response that followed kept the arena
of the debate where it was, at the aggregate level. 35 But students of the
politics of money need to revisit and build upon the insights of this lit-
erature, which was not superseded but rather was left to atrophy, as the
focus of the economics profession followed an alternative trajectory. It
is the differential, political effects of macroeconomic phenomena that
STUDY OF MONEY 427
32 Richard Cantillon, Essai sur la nature du commerce en général, ed. and trans. Henry Higgs (1931;
New York: Augustus Kelley, 1964), 161, 179, 177. For practical illustrations of distribution effects, see
pp. 163, 165. W. Stanley Jevons characterized Cantillon’s tracing of monetary disturbances as “mar-
velous.” See Jevons, “Richard Cantillon and the Nationality of Political Economy,” Contemporary Re-
view 39 ( January 1881), 72. It is important to note that Cantillon was no monetary crank; in fact, he
was quite orthodox. He did not believe that a monetary expansion would increase economic activity in
the long run. Rather, he was an opponent of inflation who believed that the inflationary process would
have self-reversing effects with attendant real economic costs. And he was sensitive to the danger that
macroeconomic policy might be manipulated by politicians for their own benefit. See Cantillon, p.
323; also Vickers (fn. 31), 212, 216; Bordo (fn. 31), 237, 251; Murphy (fn. 31), 263, 277.
33 John E. Cairnes, Essays in Political Economy: Theoretical and Applied (1873; New York: Augustus
Kelley, 1965), esp. 9, 10; also Michael Bordo, “John E. Cairnes on the Effects of the Australian Gold
Discoveries, 1851–73,” History of Political Economy 7 (Fall 1975).
34 Keynes, A Treatise on Money I: The Pure Theory of Money (1930), in Moggridge and Johnson (fn.
14), 5:81, 83–84.
35 See Perry G. Mehrling, The Money Interest and the Public Interest: American Monetary Thought,
1920–1970 (Cambridge: Harvard University Press, 1997); and Charles Rist, History of Monetary and
Credit Theory: From John Law to the Present Day, trans. Jane Degras (1940; New York: Augustus M.
Kelley, 1966), esp. 148, 375.
 
 
provide the missing link in the relationship between ideas and interests
and clarify the extent to which the choice of a “legitimate” economic
policy may be of greater political than economic consequence.
This can be illustrated with two policy examples—one regarding in-
flation management and the other, capital mobility—that are of great
practical importance and contemporary salience. In each case, one pol-
icy has a sole, consequential, and self-reinforcing claim to economic le-
gitimacy. But in each case there are also alternative policies that from
an economic perspective are equally plausible. Despite their internal
consistency, however, they are virtually unsustainable solely because
they lack legitimacy. What matters here is not the policy choice per se—
as just noted, either is plausible—but rather the way in which the win-
ning policy is anointed. Stripped of their rhetorical dressing, the aggre-
gate economic distinctions between competing policies are ambiguous
and modest and dwarfed by their differential effects. Narrow political
interests better account for the path chosen.
IMAGINE LOW INFLATION
A dramatic example of the extent to which economic legitimacy cloaks
profound political consequences can be seen with the hegemonic
proposition that vigilance against the threat of inflation must be the
primary, if not the sole, goal of macroeconomic policy. This view de-
rives from the recognition, supported by evidence, that governments
cannot call forth greater employment and production in the long run
via monetary expansion. But the only conclusion that can be drawn
from this is that governments should not purposefully promote infla-
tion to expand output. It does not address the question of whether in-
flation itself is costly or “bad” or whether suppressing inflationary
embers need be the principal goal of policy.
There are many deductive reasons why inflation might impose real
economic costs, and models can be constructed to simulate why infla-
tion should be costly in practice. Inflation, for example, can weaken the
informational role of prices. This can also reduce efficiency by increas-
ing uncertainty. There is empirical support for these propositions, as in-
flation has been shown to be associated with greater variability in prices
and the variability of real output. Inflation, as a tax on cash balances,
also carries with it the inefficiencies associated with excise taxes.36
428 WORLD POLITICS
36 For a summary of possible costs, see Stanley Fischer and Franco Modigliani, “Toward Under-
standing of the Real Effects and Costs of Inflation,” in Fischer, Indexing, Inflation, and Economic
 
 
There are, however, competing arguments that provide reasons why
some inflation might actually be a good thing (that is, the inflation rate
associated with the maximum possible rate of economic growth is pos-
itive). Such arguments often center around the view that in an econ-
omy where nominal prices are sluggish to adjust downward, some
inflation would allow changes in relative prices, an essential feature of
any growing economy, to occur faster and more efficiently. In fact, “in-
flation may be a necessary part of the process,” and deductive models
can be constructed and simulations run to show that in fact moderate
inflation “permits maximum employment and output.”37
Given the indeterminacy of deductive arguments and the relative
abundance of data on inflation rates and growth rates, the obvious next
step is to evaluate the evidence. In fact, the costs of moderate inflation
are extraordinarily difficult to find. Inflation hawk Robert Barro, who
had previously written that while economists assume that inflation is
costly, they “have not presented very convincing arguments to explain
these costs,”38 attempted to illustrate those costs in two recent papers. He
concludes that the data reveal costs that seem small yet have a cumulative
effect that is “more than enough to justify a strong interest in price sta-
bility.” He notes, however, that the “clear evidence” of the costs of in-
flation come from countries that have had inflationary episodes
exceeding 10–20 percent per year. The qualifications are even stronger
in his follow-up paper: “For inflation rates below twenty percent per
year . . . the relation between growth and inflation is not statistically
significant.”39
STUDY OF MONEY 429
Policy (Cambridge: MIT Press, 1986). On information, see Gardner Ackley, “The Costs of Inflation,”
American Economic Review 68 (May 1978). On variability, see Richard W. Parks, “Inflation and Rela-
tive Price Variability,” Journal of Political Economy 86 (February 1978). On cash-balance effects, see
Martin J. Bailey, “The Welfare Cost of Inflationary Finance,” Journal of Political Economy 64 (April
1956). Deductive models that can yield high costs of inflation include Michel Dotsey and Peter Rich-
mond, “The Welfare Cost of Inflation in General Equilibrium,” Journal of Monetary Economics 37
(February 1996); and Martin Feldstein, “The Welfare Cost of Permanent Inflation and Optimal
Short-Run Economic Policy,” Journal of Political Economy 87, no. 4 (1979).
37 James Duesenberry, “Inflation and Income Distribution,” in Eric Lundberg, ed., Inflation Theory
and Anti-Inflation Policy (Boulder, Colo.: Westview Press, 1977), 265 (first quote); George Akerlof,
William Dickens, and George Perry, The Macroeconomics of Low Inflation, Brookings Papers on Eco-
nomic Activity, no. 1 (1996), 2 (second quote). Very low inflation also might undermine monetary pol-
icy, given a nominal interest-rate floor of 0 percent.
38 Robert J. Barro and David B. Gordon, “Rules, Discretion, and Reputation in a Model of Mone-
tary Policy,” Journal of Monetary Economics 12 (February 1983), 104.
39 Robert J. Barro, “Inflation and Economic Growth,” Bank of England Quarterly Bulletin 35 (May
1995), 1, 9; and idem, “Inflation and Growth,” Federal Reserve Bank of St. Louis Review 78 (May–June
1996), 159. Critics of these papers have challenged Barro’s policy prescriptions. W. Stanners argues
that even the “weak conclusion” of the first paper “cannot be sustained.” Stanners, “Inflation and
Growth,” Cambridge Journal of Economics 20 ( July 1996), 511, also 512. In commentary following the
second paper, Kocherlakota Narayana argues that “I would recommend that policymakers not view
lower long run growth as a penalty of inflationary monetary policy” (p. 172).
 
 
Almost all of the negative relationships found between inflation and
growth are dependent on the consequences of very high levels of infla-
tion.40 Ultimately, any real economic costs of inflation, especially infla-
tion below 20 percent and certainly below 10 percent, are almost
impossible to show. While one study has claimed to demonstrate that
inflation over 8 percent is costly (with inflation below 8 percent having
a slight positive effect), another study claims to produce “direct evi-
dence against the view that inflation and output growth are reliably re-
lated in the long run.” 41 But even studies that manage to show some
relationship between inflation and growth need to be interpreted very
cautiously. 42
For those who study the politics of money, the final resolution of this
debate is not of great concern. The evidence overwhelmingly supports
the view that inflation rates at low or moderate levels have very little ef-
fect on the performance of the aggregate economy. This casts new light
on the long-held understanding that inflation has distributional conse-
quences 43 and on the less appreciated but just as important observation
430 WORLD POLITICS
40 Two prominent examples of this would be Stanley Fischer, “The Role of Macroeconomic Factors
in Growth,” Journal of Monetary Economics 32 (December 1993); and Michael Bruno, “Does Inflation
Really Lower Growth?” Finance and Development 32 (September 1995), 35, 38. Yet Bruno and Fis-
cher each support policies designed to keep inflation very low. See Fischer, “Maintaining Price Stabil-
ity,” Finance and Development 33 (December 1996), 34–37; Michael Bruno and William Easterly,
“Inflation and Growth: In Search of a Stable Relationship,” Federal Reserve Bank of St. Louis Review 78
(May–June 1996), 145.
41 Michael Sarel, “Non-linear Effects of Inflation on Economic Growth,” IMF Staff Papers 43
(March 1996); James Bullard and John W. Keating, “The Long-Run Relationship between Inflation
and Output in Postwar Economies,” Journal of Monetary Economics 36 (December 1995), 495. Bullard
and Keating also note some positive effects: “To the extent that we do find statistically significant es-
timates, they tend to be positive, with a permanent increase in inflation being associated with a per-
manent increase in the level of output” (p. 494).
42 First, the findings of studies showing relationships between inflation (and other macroeconomic
variables) and growth are quite fragile. See Ross Levine and David Renelt, “A Sensitivity Analysis of
Cross-Country Growth Regressions,” American Economic Review 82 (September 1992). Second, infla-
tion, especially high inflation, might be associated with lower economic performance because high in-
flation might be a symptom of government incompetence. In this case, the inflation could be a
symptom of government-inhibited growth rather than a cause. This is recognized by Fischer (fn. 40,
1993), 487. Third, as Bruno notes (fn. 40), an association of inflation with growth could be the result
of other factors, such as supply shocks, that would affect both factors simultaneously (p. 35).
43 Few would dispute the notion, for example, that unanticipated inflation benefits debtors at the
expense of creditors or that governments often use inflation as a means of increasing their resources
relative to society. In fact, inflation affects distribution through a multitude of channels, with differen-
tial effects on various individuals, classes, sectors, and regions.
Empirical investigations into the effects of inflation include Edward Wolff, “The Distributional Ef-
fects of the 1969–75 Inflation on Holdings of Household Wealth in the United States,” Review of In-
come and Wealth 25 ( June 1979); G. L. Bach and James Stephenson, “Inflation and the Redistribution
of Wealth,” Review of Economics and Statistics 61 (February 1974); William D. Nordhaus, “The Effects
of Inflation on the Distribution of Economic Welfare,” Journal of Money, Credit, and Banking 5 (Feb-
ruary 1973); Edward C. Budd and David F. Seiders, “The Impact of Inflation on the Distribution of
Income and Wealth,” American Economic Review 61 (May 1971); Armen A. Alchian and Reuben A.
Kessel, “Redistribution of Wealth through Inflation,” Science 130 (September 4, 1959); G. L. Bach and
 
 
by Charles Rist, that “price stability, just as much as much as price in-
stability, gives rise to inequalities as between the citizens of one and the
same country.” 44
If vigilance against inflation were the unambiguously universal opti-
mal economic policy, then these distributional quibbles would be of
only marginal interest—all groups seem to support bad policies that ad-
vance their own narrow interests. But as the economics becomes more
ambiguous, the demand for a political explanation must increase. If the
hypervigilant policy is but one plausible policy available from a larger
menu, then it is likely that the distinct distributional effects of each
policy choice, not its economic efficiency, explain the outcome.
This perspective can also explain the support for another pillar of le-
gitimacy, the sanctity of central bank independence ( CBI ). Support for
CBI derives from the need to guard against inflation. And increased CBI
is, in fact, associated with lower rates of inflation. But while there is ev-
idence that independent central banks are associated with lower infla-
tion, there is no evidence that they are associated with enhanced
economic performance. 45 This is surprising, since, for example, it was
assumed that the greater credibility of independent central banks would
cause disinflationary episodes to be both shorter and less costly. In fact,
the opposite is true. “In direct contradiction” to the credibility hypoth-
esis, “disinflation appears to be consistently more costly and no more
rapid in countries with independent central banks.” Rather than receiv-
ing a bonus, independent central banks “have to prove their toughness
repeatedly, by being tough.”46
But monetary policy can be too tight, and disinflationary policies are
unambiguously associated with output losses. A policy of emphasizing
inflation fighting and delegating responsibility for monetary policy to
STUDY OF MONEY 431
Albert Ando, “The Redistributional Effects of Inflation,” Review of Economics and Statistics 39 (Feb-
ruary 1957); Reuben A. Kessel, “Inflation Caused Wealth Redistribution: A Test of a Hypothesis,”
American Economic Review 46 (March 1956); Hyman Sardy, “The Economic Impact of Inflation in
Urban Areas,” and Zbignew Landau, “Inflation in Poland after World War I,” both in Neil Schumuk-
ler and Edward Marcus, eds., Inflation through the Ages (New York: Columbia University Press, 1983).
44 Rist (fn. 35), 375.
45 See Alberto Alesina and Lawrence H. Summers, “Central Bank Independence and Macroeco-
nomic Performance: Some Comparative Evidence,” Journal of Money, Credit, and Banking 25, no. 2
(1993); and Alex Cuckierman, “Central Bank Independence and Monetary Control,” Economic Journal
104 (1994), 1440. For a good survey of this large literature, see Sylvester Eijffinger and Jakob De
Haan, The Political Economy of Central-Bank Independence, Special Papers in International Economics
19 (Princeton: International Finance Section, Princeton University, 1996).
46 Adam Posen, “Central Bank Independence and Disinflationary Credibility: A Missing Link?”
Federal Reserve Bank of New York Staff Reports 1 (May 1995), 3, 13 (first quotes); Guy Dabelle and
Stanley Fischer, “How Independent Should a Central Bank Be,” in Jeffrey C. Fuhrer, ed., Goals, Guide-
lines and Constraints Facing Monetary Policymakers (Boston: Federal Reserve Bank of Boston, 1995),
205 (last quote); see also Eijffinger and De Haan (fn. 45), esp. 36, 38, 64.
 
 
independent central bankers devoted to crushing inflation risks disre-
garding this potential threat to the real side of the economy. 47 In any
event, the aggregate economic effects of the sole “legitimate” policy
choice ( CBI ) are modest and ambiguous.
A focus on the real, microlevel effects of monetary phenomena clar-
ifies the sharp politics, as opposed to the ambiguous economics, that is
driving macroeconomic policy. Low inflation and perhaps more impor-
tantly the macroeconomic policies designed to assure that it remains
very low benefit some groups in society at the expense of others. As
Adam Posen has argued, low inflation is only sustainable if it has ade-
quate political support. That support, he suggests, comes from numer-
ous sources but especially from “one historically prominent interest
group: the financial sector.” The financial sector supports central bank
independence “as a long-run means to price stability” and it could not
be sustained “without that group’s ongoing protection of its counter-
inflationary activities.” 48
The idea that any threat of inflation must be suppressed is the only
one that is legitimate in contemporary mainstream economic theory—
and practice. That consensus helps sustain low inflation policies and,
more importantly, serves to undermine policies that might deviate from
the norm. The evidence supports the contention, however, that the ag-
gregate economic consequences of most levels of inflation are modest,
ambiguous, and certainly dwarfed by its differential effects. 49
CAPITAL MOBILITY: IN WHOSE INTEREST ?
If inflation fighting dominates macroeconomic policy at the domestic
level, the deregulation of capital flows tops the international agenda.
Once again, however, the same combination can be observed—self-
432 WORLD POLITICS
47 It bears repeating that the ultimate resolution of the economic debate over optimal inflation pol-
icy is of small concern to students of politics, given the modest stakes. The purpose of this discussion
is not to champion one policy over another but rather to illustrate that more than one policy is theo-
retically plausible, that the perception of legitimacy can be a crucial factor in determining which pol-
icy is chosen, and that the differential effects of each easily outweigh the difference in their aggregate
economic consequences.
48 Posen also shows a correlation between the strength of the financial sector and the degree of cen-
tral bank independence. See Adam Posen, “Declarations Are Not Enough: Financial Sector Sources of
Central Bank Independence,” NBER Macroeconomics Annual 10 (1995), 254, 256, 264; idem, “Why
Central Bank Independence Does Not Cause Low Inflation: There Is No Institutional Fix For Poli-
tics,” in Richard O’Brien, ed., Finance and the International Economy 7 (1993), esp. 48.
49 Studies that have explored the differential effects of low inflation and tight monetary policies in-
clude G. J. Santoni, “The Effects of Inflation on Commercial Banks,” Federal Reserve Bank of St. Louis
Review (March 1986); T. F. Cargill and M. M. Hutchison, “The Federal Reserve and the Bank of
Japan,” in Thomas Mayer, ed., The Political Economy of American Monetary Policy (Cambridge: Cam-
bridge University Press, 1990), 172–73; Gerald Epstein and Juliet Schor, “Corporate Profitability as a
Determinant of Restrictive Monetary Policy: Estimates for the Postwar United States,” in Mayer;
 
 
fulfilling legitimacy, ambiguous economics, and underappreciated poli-
tics. And if other economic policies—in this instance, some regulation
of capital flows—are sound, plausible, and sustainable from an eco-
nomic perspective (absent problems arising solely from the perception of
legitimacy), then an explanation for the choice of one policy over another
must be rooted in political analysis, rather than in economic theory.
The idea that capital flows should not be regulated is more than just
self-fulfilling (though that is of course profoundly consequential); it is
also the express policy of both powerful states like the United States
and the international institutions that are supposed to oversee the
smooth functioning of the global economy. The support for and the
salience of the idea of freeing capital gathered momentum in the 1990s.
In the wake of this trend, the International Monetary Fund embarked
upon a fundamental revision of its charter, announcing plans in May
1997 to amend its constitution—the Articles of Agreement—“to make
the promotion of capital account liberalization a specific purpose of the
IMF and give it jurisdiction over capital movements.” 50 This would be a
dramatic change—in fact, the very opposite of what the founding fathers
of the IMF intended. They thought that capital controls were necessary
to assure the smooth functioning of an open international economy.
Thus, the Bretton Woods era, the “golden age of capitalism,” was a pe-
riod of ubiquitous capital control. Now, however, the IMF has asserted
that capital liberalization is the only legitimate path to economic effi-
ciency, and it has explicitly proclaimed that “forces of globalization
must be embraced.” Its new policy has been repeatedly characterized as
a proposition “to make unrestricted capital flows a condition of mem-
bership in the global economy.”51
As with very low inflation, there are good deductive reasons to be-
lieve in the elimination of capital controls. Openness to capital inflows
expands the resources available to the local economy, and the elimina-
tion of restrictions on capital outflows gives foreigners the confidence
to invest. Not only are investors confident that they will be able to repa-
triate their profits, but states that allow unrestricted capital flows enjoy
greater credibility: market actors assume that they are more likely to
STUDY OF MONEY 433
Jeffry Frieden, “Monetary Populism in Nineteenth Century America: An Open Economy Interpreta-
tion,” Journal of Economic History 57 ( June 1997).
50 “IMF Wins Mandate to Cover Capital Accounts,” IMF Survey (May 12, 1997), 131–32.
51 “Forces of Globalization Must Be Embraced,” IMF Survey (May 26, 1997), 131; Darren Mcder-
mott and Leslie Lopez, “Malaysia Imposes Sweeping Currency Controls: Such Capital Restrictions
Win Credence in Wake of Financial Turmoil,” Wall Street Journal, September 2, 1998; G. Pierre Goad,
“Acceptance of Capital Controls Is Spreading,” Asian Wall Street Journal, September 2, 1998, “condition
of membership” quotes.
 
 
follow “sound” policies, because if they failed to do so, they would be
subject to hemorrhaging of both foreign and domestic capital. More
generally, free capital seems to follow the logic of free trade—few deny
that an open market leads to goods results in a more efficient allocation
of resources, expanded consumption choices, and a host of other bene-
fits such as the discipline imposed by international competition.
But again, as with inflation, there are competing deductive argu-
ments that suggest that some positive level of capital control is optimal
for achieving economic efficiency. 52 The free flow of capital differs in
important ways from the free flow of goods, just like Cohen’s monetary
oligopolists differ from oligopoly producers in the real economy. Two
attributes make capital quite distinct from most real goods. First, con-
temporary technology allows investors to move huge amounts of
money almost instantaneously and at very little cost. Second, to an im-
portant extent, financial assets are worth what people think they are
worth. Given these elements, fears regarding what other people are
thinking can cause herding behavior, unleashing financial stampedes
with economic consequences that veer far from the path suggested by
any reading of the economic “fundamentals.”
Additionally, in a world of perfectly mobile capital, investors can
scan the globe for the best rates of return, and this creates pressure for
conformity across countries’ macroeconomic policies. But it is highly
unlikely that all states should be pursuing the same macroeconomic
policies at any given moment. On the contrary, because states face di-
verse economic conditions, they need to tailor their economic policies
accordingly. But without any restrictions on capital, governments that
deviate from the international norm, even when pursuing policies ap-
propriate for local needs, are “punished” by capital flight and are often
forced to abandon or even reverse such policies.
In this instance, competing deductive arguments have not been fol-
lowed by a trove of empirical studies ready for mining. Jagdish Bhag-
wati, noted champion of free trade, recently took many of his fellow
economists to task for simply assuming the case for unregulated capital.
Proponents of free trade, he observes, have provided mountains of evi-
dence to support their claims; the supporters of free capital have not. If
fact, he concludes, “the weight of evidence and the force of logic point
434 WORLD POLITICS
52 Once again, it is important to note the qualified nature of this argument. The competing argu-
ment is not that capital flows are bad but rather that completely deregulated capital would lead to a
suboptimally high level of flows.
 
 
in the opposite direction, toward restraints on capital flows.” 53 This
challenge is only reinforced by the recent study of Dani Rodrik, whose
analysis from a sample of one hundred countries finds “no evidence that
countries without capital controls have grown faster, invested more, or
experienced lower inflation.”54
Skepticism about the benefits of unlimited capital mobility would
appear to make more sense with the unexpected spread and depth of
the Asian financial crisis. Moreover, efforts by many states to defend
their currencies in an environment of mobile capital required deflation-
ary measures that only exacerbated economic distress, while countries
that had retained their capital controls were largely spared. And the cri-
sis was, to say the least, unanticipated. In September 1996 the IMF as-
serted that “international capital markets appear to have become more
resilient and are less likely to be a source of disturbances.”55 As late as
May 1997 the managing director of the IMF remarked that “global eco-
nomic prospects warranted ‘rational exuberance.’” In addition, eco-
nomic prospects were “bright” and “overheating pressures have abated
in many emerging market economies, especially in Asia—where
growth has stayed strong for several years.”56
But the IMF’s retrospective analyses of the crisis make clear that it has
not been shaken in its beliefs but remains focused on the domestic
sources of the crisis and highly suspicious of any forms of capital con-
trol. 57 However sincerely those ideas may be held, given the muddled
message yielded by the economic arguments, greater attention must be
STUDY OF MONEY 435
53 Jagdish Bhagwati, “The Capital Myth,” Foreign Affairs 77 (May–June 1998), 9, 12. For further
skepticism and qualifications, see Richard N. Cooper, “Should Capital Controls Be Banished?” Brook-
ings Papers on Economic Activity 99:1 (1999).
54 Dani Rodrik, “Who Needs Capital Account Convertibility?” in Should the IMF Pursue Capital Ac-
count Convertibility? Essays in International Finance, no. 207 (Princeton: International Finance Sec-
tion, Princeton University, May 1998), 61.
55 IMF Survey (September 23, 1996), 294. Under the headline “International Capital Markets Chart-
ing a Steadier Course,” the fund also noted that “although the scale of financial activity continues to
grow, market participants—including high-risk high-return investment funds—are more disciplined,
cautious, and sensitive to market fundamentals” (p. 293).
56 IMF Survey (May 12, 1997), 129–30.
57 International Monetary Fund, International Capital Markets: Developments, Prospects, and Key Pol-
icy Issues (Washington, D.C.: IMF , September 1998), esp. 6, 11, 57, 63, 73, 148–50; see also Interna-
tional Monetary Fund, World Economic Outlook: Financial Turbulence and the World Economy
(Washington, D.C.: IMF , October 1998), esp. 6–18, 101–2. It should be noted, however, that in the
wake of the crisis the World Bank has been willing at least to address the issue of the possible benefits
of some control over short-term capital flows. See World Bank, Global Economic Prospects and the De-
veloping Countries, 1998–99: Beyond Financial Crisis (Washington, D.C.: World Bank, 1999), esp. xi-
xii, xxi, 4, 123–24, 128, 142–52; see also World Bank, East Asia: The Road to Recovery (Washington,
D.C.: World Bank, 1998), esp. 9–10, 16, 34.
 
 

ft

تدریس تکنیکهای زبان ت پنجشنبه ۲۲ شهریور ۰۳ | ۱۹:۵۴ ۶ بازديد
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Both ferromagnetic and ferrimagnetic materials are classified as either soft or
hard on the basis of their hysteresis characteristics. Soft magnetic materials are
used in devices that are subjected to alternating magnetic fields and in which energy
losses must be low; one familiar example consists of transformer cores. For this
reason the relative area within the hysteresis loop must be small; it is characteris-
tically thin and narrow, as represented in Figure 20.19. Consequently, a soft mag-
netic material must have a high initial permeability and a low coercivity. A material
possessing these properties may reach its saturation magnetization with a relatively
low applied field (i.e., is easily magnetized and demagnetized) and still has low
hysteresis energy losses.
The saturation field or magnetization is determined only by the composition
of the material. For example, in cubic ferrites, substitution of a divalent metal
ion such as for in will change the saturation magnetization.
However, susceptibility and coercivity which also influence the shape of the
hysteresis curve, are sensitive to structural variables rather than to composition.
For example, a low value of coercivity corresponds to the easy movement of do-
main walls as the magnetic field changes magnitude and/or direction. Structural
defects such as particles of a nonmagnetic phase or voids in the magnetic mate-
rial tend to restrict the motion of domain walls, and thus increase the coercivity.
Consequently, a soft magnetic material must be free of such structural defects.
Another property consideration for soft magnetic materials is electrical resis-
tivity. In addition to the hysteresis energy losses described above, energy losses may
result from electrical currents that are induced in a magnetic material by a mag-
netic field that varies in magnitude and direction with time; these are called eddy
currents. It is most desirable to minimize these energy losses in soft magnetic ma-
terials by increasing the electrical resistivity. This is accomplished in ferromagnetic
materials by forming solid solution alloys; iron–silicon and iron–nickel alloys are
examples. The ceramic ferrites are commonly used for applications requiring
soft magnetic materials because they are intrinsically electrical insulators. Their
applicability is somewhat limited, however, inasmuch as they have relatively small
(Hc),
FeO–Fe2O3Fe2
Ni2
96 • Chapter 20 / Magnetic Properties
Hard
Soft
H
B
Figure 20.19 Schematic magnetization curves
for soft and hard magnetic materials. (From
K. M. Ralls, T. H. Courtney, and J. Wulff,
Introduction to Materials Science and
Engineering. Copyright 1976 by John Wiley
& Sons, New York. Reprinted by permission
of John Wiley & Sons, Inc.)
©
soft magnetic
material
1496T_c20_76-113 10/31/05 16:31 Page 96 FIRST PAGES
 
 
An Iron-Silicon Alloy That is Used in Transformer Cores
MATERIAL OF IMPORTANCE
As mentioned earlier in this section, trans-
former cores require the use of soft magnetic
materials, which are easily magnetized and de-
magnetized (and also have relatively high electri-
cal resistivities). One alloy commonly used for this
application is the iron–silicon alloy listed in Table
20.5 (97 wt% Fe-3 wt% Si). Single crystals of this
alloy are magnetically anisotropic, as are also single
crystals of iron (as explained above). Consequently,
energy losses of transformers could be minimized if
their cores were fabricated from single crystals such
that a [100]-type direction [the direction of easy
magnetization (Figure 20.17)] is oriented parallel to
the direction of an applied magnetic field; this con-
figuration for a transformer core is represented
schematically in Figure 20.20. Unfortunately, single
crystals are expensive to prepare, and, thus, this is
an economically unpractical situation. A better al-
ternative—one that is used commercially, being
more economically attractive—is to fabricate cores
from polycrystalline sheets of this alloy that are
anisotropic.
It is often the case that the grains in polycrys-
talline materials are randomly oriented, with the re-
sult that their properties are isotropic (Section 3.15).
However, one way of developing anisotropy in
polycrystalline metals is via plastic deformation, for
example by rolling (Section 11.4, Figure 11.8b);
rolling is the technique by which sheet transformer
cores are fabricated. A flat sheet that has been rolled
is said to have a rolling (or sheet) texture, or there is
a preferred crystallographic orientation of the grains.
For this type of texture, during the rolling operation,
for most of the grains in the sheet, a specific crys-
tallographic plane (hkl) becomes is aligned parallel
(or nearly parallel) to the surface of the sheet, and,
in addition a direction [uvw] in that plane lies par-
allel (or nearly parallel) to the rolling direction.
Thus, a rolling texture is indicated by the plane–
direction combination, (hkl)[uvw]. For body-
centered cubic alloys (to include the iron–silicon
alloy mentioned above), the rolling texture is (110)
[001], which is represented schematically in Figure
20.21. Thus, transformer cores of this iron–silicon
alloy are fabricated such the direction in which the
sheet was rolled (corresponding to a [001]-type di-
rection for most of the grains) is aligned parallel to
the direction of the magnetic field application.3
The magnetic characteristics of this alloy may
be further improved through a series of deforma-
tion and heat-treating procedures that produce a
(100)[001] texture.
Iron alloy core
Secondary
winding
Primary
winding
B field
Rolling plane
Rolling direction
[001] Direction[110] Plane
Figure 20.20 Schematic diagram of a transformer
core, including the direction of B field that is
generated.
Figure 20.21 Schematic representation of the
(110)[001] rolling texture for body-centered cubic iron.
3 For body-centered cubic metals and alloys, [100] and [001] directions are equivalent (Section 3.l0)—that is,
both are directions of easy magnetization.
20.9 Soft Magnetic Materials • 97
1496T_c20_76-113 10/31/05 16:31 Page 97 FIRST PAGES
 
 
susceptibilities. The properties of a half-dozen soft magnetic materials are shown in
Table 20.5.
The hysteresis characteristics of soft magnetic materials may be enhanced for
some applications by an appropriate heat treatment in the presence of a magnetic
field. Using such a technique, a square hysteresis loop may be produced, which is
desirable in some magnetic amplifier and pulse transformer applications. In addi-
tion, soft magnetic materials are used in generators, motors, dynamos, and switch-
ing circuits.
20.10 HARD MAGNETIC MATERIALS
Hard magnetic materials are utilized in permanent magnets, which must have a high
resistance to demagnetization. In terms of hysteresis behavior, a hard magnetic
material has a high remanence, coercivity, and saturation flux density, as well as a
low initial permeability, and high hysteresis energy losses. The hysteresis character-
istics for hard and soft magnetic materials are compared in Figure 20.19. The two
most important characteristics relative to applications for these materials are the
coercivity and what is termed the “energy product,” designated as This
corresponds to the area of the largest B-H rectangle that can be constructed
within the second quadrant of the hysteresis curve, Figure 20.22; its units are kJ/m 3
(MGOe).4 The value of the energy product is representative of the energy required
(BH)max
(BH)max.
98 • Chapter 20 / Magnetic Properties
Table 20.5 Typical Properties for Several Soft Magnetic Materials
Initial Relative Saturation Hysteresis
Composition Permeability Flux Density B s Loss/Cycle Resistivity 
Material (wt %) i [tesla (gauss)] [J/m3 (erg/cm3)] (-m)
Commercial 99.95Fe 150 2.14 270 1.0  107
iron ingot (21,400) (2700)
Silicon–iron 97Fe, 3Si 1400 2.01 40 4.7  107
(oriented) (20,100) (400)
45 Permalloy 55Fe, 45Ni 2500 1.60 120 4.5  107
(16,000) (1200)
Supermalloy 79Ni, 15Fe, 75,000 0.80 — 6.0  107
5Mo, 0.5Mn (8000)
Ferroxcube A 48MnFe 2O4, 1400 0.33 40 2000
52ZnFe 2O4 (3300) (400)
Ferroxcube B 36NiFe 2O4, 650 0.36 35 107
64ZnFe 2O4 (3600) (350)
Source: Adapted from Metals Handbook: Properties and Selection: Stainless Steels, Tool Materials and Special-
Purpose Metals, Vol. 3, 9th edition, D. Benjamin (Senior Editor), American Society for Metals, 1980.
hard magnetic
material
4 MGOe is defined as
Furthermore, conversion from cgs–emu to SI units is accomplished by the relationship
1 MGOe  7.96 kJ/m3
1 MGOe  10 6 gauss-oersted
1496T_c20_76-113 10/31/05 16:42 Page 98 FIRST PAGES
 
 
to demagnetize a permanent magnet; that is, the larger the harder is the
material in terms of its magnetic characteristics.
Again, hysteresis behavior is related to the ease with which the magnetic domain
boundaries move; by impeding domain wall motion, the coercivity and susceptibility
are enhanced, such that a large external field is required for demagnetization.
Furthermore, these characteristics are interrelated to the microstructure of the
material.
Concept Check 20.6
It is possible, by various means (i.e., alteration of microstructure and impurity ad-
ditions), to control the ease with which domain walls move as the magnetic field is
changed for ferromagnetic and ferrimagnetic materials. Sketch a schematic B-versus-H
hysteresis loop for a ferromagnetic material, and superimpose on this plot the loop
alterations that would occur if domain boundary movement were hindered.
[The answer may be found at www.wiley.com/college/callister (Student Companion Site.)]
Conventional Hard Magnetic Materials
Hard magnetic materials fall within two main categories—conventional and high
energy. The conventional materials have values that range between about
2 and 80 kJ/m3 (0.25 and 10 MGOe).These include ferromagnetic materials—magnet
steels, cunife (Cu–Ni–Fe) alloys, alnico (Al–Ni–Co) alloys—as well as the hexagonal
ferrites (BaO–6Fe2O3). Table 20.6 presents some of the critical properties of several
of these hard magnetic materials.
The hard magnet steels are normally alloyed with tungsten and/or chromium.
Under the proper heat-treating conditions these two elements readily combine with
carbon in the steel to form tungsten and chromium carbide precipitate particles,
which are especially effective in obstructing domain wall motion. For the other metal
(BH )max
(BH)max
20.10 Hard Magnetic Materials • 99
B
H
Hd
Bd  Hd < (BH)max
Bd
(BH)max
Figure 20.22 Schematic
magnetization curve that
displays hysteresis. Within
the second quadrant are
drawn two B–H energy
product rectangles; the area
of that rectangle labeled
is the largest
possible, which is greater
than the area defined by
Bd–Hd.
(BH )max
1496T_c20_76-113 10/31/05 16:31 Page 99 FIRST PAGES
 
 
alloys, an appropriate heat treatment forms extremely small single-domain and
strongly magnetic iron-cobalt particles within a nonmagnetic matrix phase.
High-Energy Hard Magnetic Materials
Permanent magnetic materials having energy products in excess of about 80 kJ/m 3
(10 MGOe) are considered to be of the high-energy type. These are recently
developed intermetallic compounds that have a variety of compositions; the two
that have found commercial exploitation are SmCo 5 and Nd 2Fe14B. Their magnetic
properties are also listed in Table 20.6.
Samarium–Cobalt Magnets
SmCo 5 is a member of a group of alloys that are combinations of cobalt or iron and
a light rare earth element; a number of these alloys exhibit high-energy, hard mag-
netic behavior,but SmCo 5 is the only one of commercial significance. The energy
products of these SmCo 5 materials [between 120 and 240 kJ/m 3 (15 and 30 MGOe)]
are considerably higher than the conventional hard magnetic materials (Table 20.6);
in addition, they have relatively large coercivities. Powder metallurgical techniques
are used to fabricate SmCo 5 magnets. The appropriately alloyed material is first
ground into a fine powder; the powder particles are aligned using an external mag-
netic field and then pressed into the desired shape. The piece is then sintered at an
elevated temperature, followed by another heat treatment that improves the mag-
netic properties.
Neodymium–Iron–Boron Magnets
Samarium is a rare and relatively expensive material; furthermore, the price of cobalt
is variable and its sources are unreliable. Consequently, the Nd 2Fe14B alloys have
become the materials of choice for a large number and wide diversity of applications
100 • Chapter 20 / Magnetic Properties
Table 20.6 Typical Properties for Several Hard Magnetic Materials.
Remanence Coercivity Curie
Br Hc (BH)max Temperature Resistivity
Composition [tesla [amp-turn/m [kJ/m3 Te 
Material (wt %) (gauss)] (Oe)] (MGOe)] [C(F)] (-m)
Tungsten 92.8 Fe, 0.95 5900 2.6 760 3.0  107
steel 6 W, 0.5 (9500) (74) (0.33) (1400)
Cr, 0.7 C
Cunife 20 Fe, 20 0.54 44,000 12 410 1.8  107
Ni, 60 Cu (5400) (550) (1.5) (770)
Sintered alnico 8 34 Fe, 7 Al, 0.76 125,000 36 860 —
15 Ni, 35 (7600) (1550) (4.5) (1580)
Co, 4 Cu,
5 Ti
Sintered ferrite 3 BaO–6Fe 2O3 0.32 240,000 20 450 104
(3200) (3000) (2.5) (840)
Cobalt rare earth 1 SmCo 5 0.92 720,000 170 725 5.0  107
(9200) (9,000) (21) (1340)
Sintered neodymium- Nd2Fe14B 1.16 848,000 255 310 1.6  106
iron-boron (11,600) (10,600) (32) (590)
Source: Adapted from ASM Handbook, Vol. 2, Properties and Selection: Nonferrous Alloys and Special-Purpose
Materials. Copyright 1990 by ASM International. Reprinted by permission of ASM International, Materials
Park, OH.
©
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requiring hard magnetic materials. Coercivities and energy products of these
materials rival those of the samarium–cobalt alloys (Table 20.6).
The magnetization–demagnetization behavior of these materials is a function
of domain wall mobility, which, in turn, is controlled by the final microstructure—
that is, the size, shape, and orientation of the crystallites or grains, as well as the na-
ture and distribution of any second-phase particles that are present. Of course,
microstructure will depend on how the material is processed. Two different pro-
cessing techniques are available for the fabrication of Nd 2Fe14B magnets: powder
metallurgy (sintering) and rapid solidification (melt spinning). The powder metal-
lurgical approach is similar to that used for the SmCo 5 materials. For rapid
solidification, the alloy, in molten form, is quenched very rapidly such that either
an amorphous or very fine grained and thin solid ribbon is produced. This ribbon
material is then pulverized, compacted into the desired shape, and subsequently
heat treated. Rapid solidification is the more involved of the two fabrication
processes; nevertheless, it is continuous, whereas powder metallurgy is a batch
process, which has its inherent disadvantages.
These high-energy hard magnetic materials are employed in a host of different
devices in a variety of technological fields. One common application is in motors.
Permanent magnets are far superior to electromagnets in that their magnetic fields
are continuously maintained and without the necessity of expending electrical
power; furthermore, no heat is generated during operation. Motors using permanent
magnets are much smaller than their electromagnet counterparts and are utilized
extensively in fractional horsepower units. Familiar motor applications include the
following: in cordless drills and screw drivers; in automobiles (starting, window
winder, wiper, washer, and fan motors); in audio and video recorders; and in clocks.
Other common devices that employ these magnetic materials are speakers in audio
systems, lightweight earphones, hearing aids, and computer peripherals.
20.11 MAGNETIC STORAGE
Within the past few years, magnetic materials have become increasingly important
in the area of information storage; in fact, magnetic recording has become virtually
the universal technology for the storage of electronic information. This is evidenced
by the preponderance of audio tapes, VCRs, disk storage media, credit cards, and
so on. Whereas in computers, semiconductor elements serve as primary memory,
magnetic disks are used for secondary memory because they are capable of storing
larger quantities of information and at a lower cost. Furthermore, the recording and
television industries rely heavily on magnetic tapes for the storage and reproduc-
tion of audio and video sequences.
In essence, computer bytes, sound, or visual images in the form of electrical sig-
nals are recorded on very small segments of the magnetic storage medium—a tape
or disk.Transference to and retrieval from the tape or disk is accomplished by means
of an inductive read–write head, which consists basically of a wire coil wound around
a magnetic material core into which a gap is cut. Data are introduced (or “written”)
by the electrical signal within the coil, which generates a magnetic field across the
gap. This field in turn magnetizes a very small area of the disk or tape within the
proximity of the head. Upon removal of the field, the magnetization remains; that
is, the signal has been stored. The essential features of this recording process are
shown in Figure 20.23.
Furthermore, the same head may be utilized to retrieve (or “read”) the stored
information. A voltage is induced when there is a change in the magnetic field as
20.11 Magnetic Storage • 101
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the tape or disk passes by the head coil gap; this may be amplified and then con-
verted back into its original form or character. This process is also represented in
Figure 20.23.
Recently, hybrid heads that consist of an inductive-write and a magnetoresistive
read head in a single unit have been introduced. In the magnetoresistive head, the
electrical resistance of the magnetoresistive thin film element is changed as a result
of magnetic field changes when the tape or disk passes by the read head. Higher sen-
sitivies and higher data transfer rates make magnetoresistive heads very attractive.
There are two principal types of magnetic media—particulate and thin film.
Particulate media consist of very small needle-like or acicular particles, normally
of -Fe 2 O 3 ferrite or CrO 2 ; these are applied and bonded to a polymeric film
(for magnetic tapes) or to a metal or polymer disk. During manufacture, these
particles are aligned with their long axes in a direction that parallels the direc-
tion of motion past the head (see Figures 20.23 and 20.24). Each particle is a
g
102 • Chapter 20 / Magnetic Properties
Recording medium
Recording
head
Signal
in Write
Signal
out
Read
Width
Gap
Figure 20.23 Schematic
representation showing how
information is stored and
retrieved using a magnetic
storage medium. (From J. U.
Lemke, MRS Bulletin, Vol. XV,
No. 3, p. 31, 1990. Reprinted with
permission.)
Figure 20.24 A scanning electron
micrograph showing the microstructure
of a magnetic storage disk. Needle-shaped
particles of -Fe2O3 are oriented and
embedded within an epoxy phenolic resin.
8000. (Photograph courtesy of P. Rayner
and N. L. Head, IBM Corporation.)
g
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single domain that may be magnetized only with its magnetic moment lying along
this axis. Two magnetic states are possible, corresponding to the saturation mag-
netization in one axial direction, and its opposite. These two states make possi-
ble the storage of information in digital form, as 1’s and 0’s. In one system, a 1
is represented by a reversal in the magnetic field direction from one small area
of the storage medium to another as the numerous acicular particles of each such
region pass by the head. A lack of reversal between adjacent regions is indicated
by a 0.
The thin-film storage technology is relatively new and provides higher storage
capacities at lower costs. It is employed mainly on rigid disk drives and consists of
a multilayered structure. A magnetic thin-film layer is the actual storage compo-
nent (see Figure 20.25). This film is normally either a CoPtCr or CoCrTa alloy, with
a thickness of between 10 and 50 nm. A substrate layer below and upon which the
thin film resides is pure chromium or a chromium alloy. The thin film itself is
20.11 Magnetic Storage • 103
(b)
(a)
Figure 20.25 (a) A high-
resolution transmission
electron micrograph showing
the microstructure of a
cobalt–chromium–platinum
thin film that is used as a
high-density magnetic storage
medium. The arrow at the
top indicates the motion
direction of the medium.
500,000. (b) A
representation of the grain
structure for the electron
micrograph in (a); the arrows
in some of the grains indicate
the texture, or the direction
of easy magnetization. (From
M. R. Kim, S. Guruswamy,
and K. E. Johnson, J. Appl.
Phys., Vol. 74, No. 7, p. 4646,
1993. Reprinted with
permission.)
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polycrystalline, having an average grain size that is typically between 10 and 30 nm.
Each grain within the thin film is a single magnetic domain, and it is highly desir-
able that grain shape and size be relatively uniform. For magnetic storage disks that
employ these thin films, the crystallographic direction of easy magnetization for
each grain is aligned in the direction of disk motion (or the direction opposite) (see
Figure 20.25). The mechanism of magnetic storage within each of these single-
domain grains is the same as for the needle-shaped particles, as described above—
that is, the two magnetic states correspond to domain magnetization in one direction
or its antiparallel equivalent.
The storage density of thin films is greater than for particulate media because
the packing efficiency of thin-film domains is greater than for the acicular particles;
particles will always be separated with void space in between. At the time of this
writing, storage densities for particulate media are on the order of bit/in. 2
For thin films, storage densities are approximately an order of
magnitude greater [i.e.,
Regarding specific magnetic properties, the hysteresis loops for these magnetic
storage media should be relatively large and square. These characteristics ensure
that storage will be permanent, and, in addition, magnetization reversal will result
over a narrow range of applied field strengths. For particulate recording media,
saturation flux density normally ranges from 0.4 to 0.6 tesla (4000 and 6000 gauss).
For thin films, will lie between 0.6 and 1.2 tesla (6000 and 12,000 gauss).
Coercivity values are typically in the range of to A/m (2000 to
3000 Oe).
20.12 SUPERCONDUCTIVITY
Superconductivity is basically an electrical phenomenon; however, its discussion has
been deferred to this point because there are magnetic implications relative to the
superconducting state, and, in addition, superconducting materials are used prima-
rily in magnets capable of generating high fields.
As most high-purity metals are cooled down to temperatures nearing 0 K, the
electrical resistivity decreases gradually, approaching some small yet finite value
that is characteristic of the particular metal. There are a few materials, however, for
which the resistivity, at a very low temperature, abruptly plunges from a finite value
to one that is virtually zero and remains there upon further cooling. Materials that
display this latter behavior are called superconductors, and the temperature at which
they attain superconductivity is called the critical temperature 5 The resistivity–
temperature behaviors for superconductive and nonsuperconductive materials are
contrasted in Figure 20.26. The critical temperature varies from superconductor to
superconductor but lies between less than 1 K and approximately 20 K for metals
and metal alloys. Recently, it has been demonstrated that some complex oxide
ceramics have critical temperatures in excess of 100 K.
At temperatures below the superconducting state will cease upon applica-
tion of a sufficiently large magnetic field, termed the critical field which de-
pends on temperature and decreases with increasing temperature. The same may
be said for current density; that is, a critical applied current density exists below

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City’s continued importance as an entry point for new immigrants is demonstrated by the fact that
nearly 170 languages (per the New York City Department of Planning) are spoken in the city and
an estimated 36 percent of the population was born outside of the United States (US Census).
New York City is also geographically unique. It is a city of islands with four of the five New York
City boroughs on islands (Manhattan, Staten Island, and Long Island, where Brooklyn and
Queens are located). Only the Bronx is on the New York State mainland. New York City’s
islands and boroughs are separated by a series of rivers and waterways. Manhattan, for
example, is separated from New Jersey by the Hudson River, and the Harlem and East Rivers
separate Manhattan from the Bronx and Long Island. Long Island Sound separates the Bronx
from Queens. Staten Island is separated from Brooklyn, Manhattan, and New Jersey by New
York Harbor. Thus the city’s urban infrastructure consists of ferries, bridges and tunnels,
including subway tunnels.
Area
New York City’s land area is approximately 469 square miles, which include 304 square miles of
land and 165 square miles of water (see Figure 3-2). The land area of New York is roughly
equivalent to Kansas City (305 square miles) and slightly larger than Augusta, Georgia (302
square miles).
Within New York City, the two boroughs on Long Island are substantially larger geographically
than their counterparts. With a land area of 109 sq mi, Queens is by far the largest borough, with
Brooklyn representing the next largest land area of 71 sq mi. The Bronx and Manhattan are the
smallest with only 42 and 23 sq mi respectively.
Figure 3-2 NYC Subregion Area by Borough
Total Area (Sq. Miles) Land Area (Sq Miles)
Bronx 57 42
Brooklyn 97 71
Manhattan 34 23
Queens 178 109
Staten Is. 103 59
NYC 469 304
Source: US Census (2000); figures are rounded estimates
Population and Population Growth
New York City has been the most populated city in the United States since 1790, when it
surpassed Philadelphia. By the year 1900, NYC already contained 3.4 million residents. The
population of NYC more than doubled over the next 50 years, growing to 7.89 million residents in
1959. The population growth stemmed from a series of domestic and international immigration,
including domestic immigration from the southern states in the 1920s and the post World War II
boom, which brought large numbers of European immigrants to New York City.
Between 1950 and 1980, population growth slowed considerably. New York City experienced
economic problems in the 1960s and 1970s and the city suffered from social unrest created by
racial tensions, and rising crime rates that continued until the 1970s. Indeed, between 1970 and
 
 
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1980, NYC lost 10 percent of its residents. New York City recovered from this period of unrest
and the 1980s saw a resurgence in the financial industry, lower crime rates, an ease in the racial
tensions and a new wave of immigrants from Asia and Latin America. The population of NYC has
grown considerably since 1980, surpassing 8 million people by 2000.
From 2000 to 2007, the city grew 3.3 percent, from 8 million to nearly 8.3 million residents. This
is a faster rate of growth than the 1.7 percent experienced by New York State, but much lower
than the national growth rate of 7.2 percent, reflecting the national trend of slower growth in the
northeast as compared with the “sun belt” in the southeast and southwest.
The population and population growth of each borough is shown in Figure 3-3. Among the
boroughs, Brooklyn has the highest population (as of 2007) at over 2.5 million, while Staten
Island, at nearly 444,000 is the least populated of the boroughs. In terms of growth as a
percentage, Staten Island experienced the greatest population growth from 2000 to 2007, at 8.5
percent, while Queens experienced the least population growth, at 1.8 percent.
Figure 3-3 NYC Subregion Population and Population by Borough
2000 Pop. % 2007 Pop. % Change % Change
Bronx 1,332,650 16.6% 1,373,659 16.6% 41,009 3.1%
Brooklyn 2,465,326 30.8% 2,528,050 30.6% 62,724 2.5%
Manhattan 1,537,195 19.2% 1,620,867 19.6% 83,672 5.4%
Queens 2,229,379 27.8% 2,270,338 27.4% 40,959 1.8%
Staten Is. 443,728 5.5% 481,613 5.8% 37,885 8.5%
NYC 8,008,278 8,274,527 266,249 3.3%
Source: US Census (2000); figures are rounded estimates
Population Density
As shown in Figure 3-4, NYC has a population density of more than 26,000 people per square
mile (Census 2000). In comparison, the second largest city in the United States, Los Angeles,
covers 469 square miles of land and has a population density of 8,200 people per square mile.1
1 2000 Census and 2007 American Fact Finder
Note that the 26,000 people per square mile average is skewed downward by the inclusion of
Staten Island. With the third largest land area but the lowest population, Staten Island exhibits a
population density of only 7,600 people per square mile. On the other end of the density
spectrum, Manhattan holds the title of the most densely populated county in the US. With the
smallest land area and the third largest population of the boroughs, Manhattan has the incredible
population density of nearly 67,000 people per square mile.
 
 
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Figure 3-4 Population Density by NYC Borough (2000)
2000 Pop. Area (Sq Mi) Density
Bronx 1,332,650 42 31,709
Brooklyn 2,465,326 71 34,916
Manhattan 1,537,195 23 66,940
Queens 2,229,379 109 20,409
Staten Is. 443,728 59 7,587
NYC 8,008,278 304 26,257
Source: US Census (2000); figures are rounded estimates
Population Age Distribution
The median age of New York City residents is 35.9, which is slightly lower than the median for
New York State (37.0) and the US as a whole (36.4). As shown in Figure 3-5, older adults
account for 12 percent of the population, while 64 percent of the residents are between the ages
of 18-64.
The share of population over 65 years old remains constant (10% to 13%) across the boroughs,
however, in absolute terms Brooklyn has nearly 283,000 older adults, while Staten Island has
only 51,000.
Children under the age of 18 account for 24 percent of the city’s total population but the share
ranges across the city from only 17 percent in Manhattan up to 30 percent in the Bronx.
Figure 3-5 NYC Subregion Age Distribution by Borough (2000)
Under 18 18-64 65 and Over Total Percentage of
Citywide total
Bronx Population 397,372 801,330 133,948 1,332,650 17%
Percentage 30% 60% 10%
Brooklyn Population 662,499 1,520,169 282,658 2,465,326 31%
Percentage 27% 62% 11%
Manhattan Population 257,916 1,092,503 186,776 1,537,195 19%
Percentage 17% 71% 12%
Queens Population 509,224 1,437,113 283,042 2,229,379 28%
Percentage 23% 64% 13%
Staten Is. Population 113,258 279,037 51,433 443,728 6%
Percentage 26% 63% 12%
NYC Population 1,940,269 5,070,645 937,857 8,008,278 100%
Percentage 24% 64% 12%
Source: US Census (2000); figures are rounded estimates
 
 
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Persons with Disability
New York City is home to a proportionately large population of persons with a disability over the
age of five (1,815,012 as of the 2000 Census), representing 23 percent of the total population, or
25 percent of the population over five. In comparison, persons with a disability are only 19
percent of New York State’s population and 18 percent of the nation’s population.
Income
A defining characteristic of New York City is the disparity in individual and household incomes.
Despite being one of the wealthiest urban areas in the world, NYC has a large population of low
income residents. Consequently, NYC’s median income ($38,293 according to the 2000 US
Census) is lower than New York State ($43,393) and the national average ($41,994). With 2.4
million people qualifying as low income, the city’s low income percentage is approximately 30
percent, compared to the national average of 20 percent.
Employment
New York City is an international hub of business and commerce and one of the largest urban
economies in the world. It is the largest regional economy in the United States and is a major
center for finance, insurance, real estate, media and the arts in the United States. NYC’s
signature industry is the financial sector, represented by Wall Street, which is the world largest
stock exchanged (measured by daily trading volumes). The financial sector accounts for 35
percent of the employment income in New York City. Other major industries include real estate,
television and film, creative industries (advertising, fashion, design and architecture) as well as
high tech industries, medical research and education. Manufacturing is also an important
industry in NYC, although it has held a declining share of employment. In total, there are some
3.2 million jobs2
2 “Employment in New York – October 2008”, New York State Department of Labor Quarterly Newsletter, published by
the Division of Research and Statistics.
.
 
 
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Profile of the Bronx
Overview
As shown in Figure 3-6, the Bronx is the northernmost borough in New York City. Bordering the
Bronx is Westchester County (and the cities of Yonkers and Mount Vernon) to the north, the
Hudson and Harlem Rivers to the west, Long Island Sound to the East, and the East River to the
south. With a population between 1.33
Figure 3-6 Bronx Location within the NYMTC Region
and 1.4 million people, which reflects 17 percent of NYC’s
population, the Bronx is second lowest in population among the five boroughs. The Bronx is
world famous for being the home of Yankee Stadium and the Bronx Zoo. The main campus of
Fordham University is also located in the Bronx.
Several interstate highways and parkways crisscross the borough, as shown in Figure 3-7.
These include I-87 (the New York Thruway) I-95 (Cross Bronx Expressway), I-278 (Bruckner
Expressway), I-695 (The Throgs Neck Expressway), I-295, I-895, the Hutchinson Parkway, Saw
Mill River Parkway, and the Bronx River Parkway. The Bronx is connected to Manhattan by
several bridges, and to Queens by The Throgs Neck Bridge, The Whitestone Bridge, and the
Robert F. Kennedy-Triborough Bridge.
3 American Fact Finder, US Census 2000
 
 
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Figure 3-7 Bronx Detail
The Bronx is served by public transportation services operated by the Metropolitan Transportation
Authority. Several subway lines connect the Bronx to Manhattan (1, 2, 4, 5, 6, B, and D), some of
which (2, 4, 5, B, and D) continue on to Brooklyn. No subway line directly connects the Bronx
with Queens, though two bus routes (the QBx1 and the Q44) do. In addition to these subway
lines, local and limited stop buses provide circulation within the borough while express buses
provide commuter services connecting the Bronx to Manhattan. Metro-North also provides
commuter rail service between the Bronx and Manhattan, as well as providing reverse commute
services to work destinations in the Lower Hudson Valley and Connecticut. Access-A-Ride
services are available throughout the borough providing curb to curb services for qualified
passengers. Westchester Bee-Line also provides services in the Bronx.
 
 
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Area
Geographically, the Bronx is the second smallest borough, covering 42 square miles of land. It
sits just north of Manhattan and just south of Westchester County and is the only borough directly
connected to the mainland.
Population and Population Growth
As shown in Figure 3-3, the Bronx’s population in 2000 was 1,332,650, second smallest (to
Staten Island) of the five boroughs. By 2007, the Bronx population had grown to 1,373,659, an
increase of 3.1 percent from 2000.
Total population by zip code is presented in Figure 3-8. The most populated zip code is 10467 in
Fordham, with a 2000 population of 96,340.
Population Density
As shown in Figure 3-8, the population density of the Bronx in the Year 2000 was 31,709 people
per square mile, meaning the Bronx’s population density is the third highest of the boroughs and
fairly similar to Brooklyn, which has 34,916 persons per square mile. In comparison, the
population density of NYC as a whole was 26,257 persons per square mile in 2000. For the
same year, the population densities of New York State and United States were 402 and 80
persons per square mile, respectively.
Total population density by zip code is also shown in Figure 3-8. Local densities ranged from 36
persons per square mile in zip code 10464 in Pelham to 86,883 persons per square mile in zip
code 10453 in the Morris Heights section of the Bronx.
Population Age Distribution
The median age of residents of the Bronx is 31.2 years old, compared to New York City overall
(35.9) and the US (36.4). According to the US Census, there were approximately 134,000 older
adults living in the Bronx in 2000, accounting for 10 percent of the population. Figure 3-5 shows
the distribution of the borough’s older adult population. Overall, the density of older adults was
3,189 persons per square mile in the Bronx in 2000.
Population of Persons with Disabilities
There were 340,121 persons with disabilities living in the Bronx in 2000, accounting for about 28
percent of the total population, and resulting in a density of 8,098 persons with disabilities per
square mile.
Income
Residents of the Bronx earned a median household income of about $28,000 in 2000, the lowest
median income in NYC. The Bronx has a high percentage of low income residents, with 31
percent of the borough’s population or 395,263 persons living below the poverty level, and with a
density of 9,411 low income persons per square mile.
 
 
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Figure 3-8 Bronx Population and Population Density Distribution by Zip Code (2000)
ZIP
Code General Area Square
Miles
Total Population
Population Density
10467 Fordham 2.82 96,340 34,105
10453 Morris Heights 0.91 79,319 86,883
10468 Fordham 1.09 78,243 71,517
10457 Tremont 1.23 73,979 59,935
10456 High Bridge 1.07 73,538 68,971
10458 Fordham 1.22 72,245 59,347
10452 High Bridge 0.96 70,443 73,474
10462 Pelham 1.47 69,936 47,457
10466 Edenwald 2.07 69,536 33,647
10472 Parkchester 1.11 65,368 58,813
10469 Edenwald 2.56 62,822 24,571
10473 Soundview 2.09 60,718 29,096
10463 Kingsbridge 1.74 56,921 32,756
10460 Tremont 1.64 52,034 31,671
10461 Pelham 2.30 48,820 21,239
10465 Throgs Neck 3.73 42,008 11,248
10451 High Bridge 1.03 41,902 40,637
10459 Hunts Point 0.87 40,999 47,317
10455 Mott Haven 0.71 38,132 53,600
10475 Co-Op City 1.14 36,614 31,988
10454 Mott Haven 1.07 35,412 33,238
10471 Riverdale 2.87 25,283 8,810
10470 Woodlawn 0.88 16,089 18,263
11370 Riker's Island* 0.65 12,581 19,468
10474 Hunts Point 1.49 11,153 7,492
10464 Pelham 0.41 4,402 10,608
10475 Co-Op City 0.26 530 2,020
10464 Pelham 2.70 97 36
Source: US Census (2000); figures are rounded estimates
*Riker’s Island is politically part of the Bronx, though it has a Queens zip code. The US Census includes it in
Bronx County, and it remains here in the Census analysis presented in this chapter.
 
 
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Employment
Approximately 51 percent of the Bronx’s population is in the labor force. As of July 2008, the
unemployment rate in the Bronx was 6.5 percent. Roughly 41 percent of the population works in
the Bronx, while 47 percent work outside, including a large segment commuting to Manhattan and
Westchester County and Stamford, CT. Most of the jobs within the borough are in the
educational, health, and social services industries. Another key characteristic of the Bronx’s
economy is the scale of the borough’s employers; according to the US Census, 89 percent of the
businesses operating in the Bronx had a workforce of 20 employees or less. The Bronx’s
commercial activity is located at major cross-roads such as Fordham Plaza near the intersection
of Fordham Road and Grand Concourse, the hub at Webster Avenue and 149 Street, and the
courthouse area located at 161 Street and Grand Concourse. Along major corridors there is
some commercial activity. There are also a number of office parks located in the eastern parts of
the Bronx

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تدریس تکنیکهای زبان ت پنجشنبه ۲۲ شهریور ۰۳ | ۱۹:۱۶ ۷ بازديد
The slaves called Harriet Tubman “Moses” because she delivered
them from slavery. In the South, a reward of $12,000 was offered
for her capture. No one was ever able to collect it. Many years
later, when she looked back on her work in the Underground
Railroad, Harriet Tubman said, “I never ran my train off the track,
and I never lost a passenger.”
Although Harriet Tubman looked back with pride on her success
in leading runaway slaves to freedom, only a small number of
slaves achieved freedom through the Underground

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تدریس تکنیکهای زبان ت پنجشنبه ۲۲ شهریور ۰۳ | ۱۹:۱۵ ۹ بازديد
26
It’s hard to understand that not everyone has always felt this way.
But the sad fact is that slavery has existed in many times and
places, including in ancient Greece and ancient Rome, in Africa, in
parts of Europe during the Middle Ages, and elsewhere. It’s been
only in the last 250 years, really, that a growing number of people
have come to believe that slavery is unacceptable. And even when
many people finally began to believe that slavery was wrong, few
were ready to do anything to get rid of it.
The first chapter explained how a number of slaveholders, moved
by the words of the Declaration of Independence, freed their
slaves. In the early 1800s, however, few slave owners were willing
to do so. And while many people in the North didn’t want to see
slavery spread any farther, very few raised their voices against it
where it already existed. That is why Congress believed that, in
passing the Missouri Compromise, they had ended the argument
about slavery once and for all.
But by the 1820s a small number of Americans began to speak
out against slavery in general. Some searched for practical ways
to end the practice. Some simply tried to persuade owners to
treat their slaves more like human beings than like property.
Others hoped to get more owners to agree that after they died,
their slaves would become free. Still others believed that slavery
might be ended gradually by paying owners who agreed to give
up their slaves. Ending slavery in this way would take many, many
years. Most politicians agreed that the states controlled whether
there was slavery in the South. They believed that Congres

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تدریس تکنیکهای زبان ت پنجشنبه ۲۲ شهریور ۰۳ | ۱۹:۱۳ ۷ بازديد
Whitney’s invention made it possible for Southerners to sell
their cotton cheaply. Factories in the North, and especially in
Great Britain, were now ready to buy all the cotton the South
could grow. Soon, planters started large plantations on rich lands
in the Mississippi and Alabama territories. Cotton quickly became
The cotton gin made cotton a profitable crop in the Southern states and territories.
 
 
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the South’s most important crop. By 1820, the South grew one
hundred times as much cotton as it had raised before Eli Whitney
built his cotton gin.
To grow this cotton, the plantation owners
needed more laborers to plow, plant,
cultivate, and harvest. As a result, slaves
were in greater demand than ever. The
price of buying a slave doubled. Far from freeing their slaves,
Southern planters now sought to buy more slaves.
Vocabulary
cultivate, v. to help
grow
 
 
Chapter 2
The Life of the Slave
Slavery in the South What was
life like for slaves in the American
South? Much depended on where
they worked and who owned them.
Slaves on small farms usually worked
in the fields alongside their owners. They did many
other tasks, too. On a small farm, everyone did a little
bit of everything.
On large plantations, however, slaves usually did only one task.
A small number worked and lived in the great house with the
master’s family. These house servants cooked, cleaned, and did
other housework. They also helped raise the master’s children. Some
other slaves became skilled carpenters, blacksmiths, brick makers,
and barrel makers. By far, however, most slaves on a large plantation
worked in the fields.
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The Big Question
How did slaves in the
South resist?
 
 
Enslaved men, women, and children worked in the fields on large plantations.11
 
 
12
Whether they lived on a small farm or a great plantation, slaves
worked from dawn until dusk. Hard work, however, is not what
made slavery a terrible thing. After all, many people who were
not slaves also worked hard.
No, what made slavery wrong was that
slaves were not free. They did not have,
as in the words of the Declaration of
Independence, the right to “life, liberty,
and the pursuit of happiness.” Another person owned them
without their consent and was their master. Another person
owned their labor and the fruits of that labor.
An owner could treat his slaves like pieces of property. He could
buy them; he could sell them. He could sell some members of
a slave family and not others, or sell husbands and wives and
children to different buyers. In fact, three in every ten slave
families were broken up by such sales.
Slaves could be whipped for not working hard enough or fast
enough, or for not showing proper respect to members of their
owner’s family, or for many other small reasons—sometimes for
no reason at all. Not all owners were this cruel, but some certainly
were. Violence was essential to the slave system, or the slaves
would stop working for free and walk away.
In addition, slaves could not leave the plantation without their
owner’s permission. Only the kindest and most unusual of
owners allowed their slaves to be educated. In many states, it
was illegal to teach slaves to read and write. A famous slave
Vocabulary
consent, n. approval
or agreement
 
 
13
named Frederick Douglass later said he recovered his manhood
and humanity when he learned to read.
Slave Resistance
Slave owners told themselves, and anyone else who would listen,
that their slaves were happy. And probably some of these slave
owners actually believed that. Of course, if the slaves were really

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تدریس تکنیکهای زبان ت پنجشنبه ۲۲ شهریور ۰۳ | ۱۹:۱۳ ۸ بازديد
emarkable Anniversary The
date was July 3, 1826. As the fiftieth
anniversary of the Declaration
of Independence approached, a
great drama was playing itself out
in the homes of two of the men most responsible
for that document. At Monticello in Virginia, Thomas
Jefferson, now age eighty-three, slipped in and out of
consciousness as he lay on his deathbed.
And in Quincy, Massachusetts, John Adams, now age ninety, also
neared the end of his life. Would these two great patriots and former
presidents live to see this fiftieth Independence Day? Americans
everywhere hoped and prayed that they would.
As midnight arrived, Thomas Jefferson stirred in his bed and
whispered to a young relative, “This is the Fourth?” The young man
nodded. Jefferson sighed contentedly. He said no more, and by noon
he was gone.
2
The Big Question
Why did the demand
for slaves increase in
the Southern states?
 
 
Thomas JeffersonJohn Adams3
 
 
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At that very moment in Quincy, Massachusetts, the roar of a
cannon signaled the start of the town’s celebration. John Adams
struggled to utter what proved to be his last sentence. His
granddaughter, bending close to the old man, was able to hear
his final whispered words, “Thomas—Jefferson—still—surv—.”
Before the sun had set, he too was gone.
In their lifetimes, Thomas Jefferson and John Adams had seen
their beloved United States grow from a struggling group of
new states into a strong, confident nation. During the fifty years
following the Declaration of Independence, the United States
had gained vast new lands and developed into a democracy
that was a model for countries around the world.
In one important way, however, America
had not changed and was not a model
at all. Almost from the beginning, even
during colonial times, slavery had been
part of American life. When the thirteen
colonies became the first thirteen states,
nearly one in every five Americans was an African American.
Nearly all African Americans were enslaved. By far, most of these
slaves lived in the South. But there were slaves in the Northern
states, too. At the time of the American Revolution, for example,
one in every ten New Yorkers was a slave. Slaves in the North
worked mainly as house servants for rich families. Now, fifty years
later, Southerners wanted to see slavery spread to the
new western territories as well.
Vocabulary
slavery, n. a system
in which people are
legally owned by
another and forced to
work without pay
 
 
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For a short time after the Declaration of Independence was
written, there seemed a slim chance that slavery might die out.
That was partly because of the words that lie at the very heart of
the Declaration:
We hold these truths to be self-evident;
that all men are created equal, that
they are endowed by their Creator with
certain unalienable rights, that among
these are life, liberty, and the pursuit of
happiness.
So how could people accept slavery and still live up to the
words of the Declaration of Independence? A growing number
of Americans, both Northerners and Southerners, believed that
they could not. As John Adams wrote to his wife, Abigail, slaves
“have as good a right to freedom as we have.” Some Americans
freed their slaves during the Revolutionary War era. Before long,
all the Northern states took steps to end slavery. The Northwest
Ordinance banned slavery in five new western states. Congress
ended the slave trade in 1808. The Constitution had provided for
the end of the slave trade in 1808. No Southern state went so far
as to free all the slaves, but a few made it easier for slave owners to
free their slaves if they wished to.
The former president, George Washington, owned many slaves at
Mount Vernon, his home in Virginia. He and other slave owners
who believed that slavery was wrong, declared that when they
died, their slaves were to be set free. By the early 1800s, there were
about 150,000 free African Americans. Most of them lived in the
Vocabulary
self-evident, adj.
obvious
unalienable, adj.
unable to be taken
away or denied
 
 
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Southern states. However, for most slaves in
the South, freedom was still out of reach.
But not everyone who believed slavery was
wrong favored equal civil rights for freed
African Americans. This was certainly true
in the five new western states to which the
Northwest Ordinance applied. Ending slavery was one thing. Allowing
African Americans to have the full rights of citizens—like voting,
holding office, serving on juries, living where they wanted to live,
working in whatever jobs they chose—was something else altogether.
While some people, such as Abraham Lincoln, did believe that
the rights outlined in the Declaration of Independence extended
to people of color—free or enslaved – many did not. For many
Like many others living in the South, George Washington owned slaves on his estate at
Mount Vernon.
Vocabulary
civil rights, n. the
rights that all citizens
are supposed to
have according to
the Constitution and
its amendments
 
 
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people, the notion of liberty had more to do with self-government
and the possibility of rising up economically than with the removal
of racial slavery or with equal rights for people of color.
The Cotton Gin
Despite progress, by 1810, almost no slave owners were willing
to free their slaves. What caused the change in attitude? Slaves
had become much more valuable. A new invention called the
cotton gin now made it even more profitable to use slave labor
to grow cotton. Southerners began growing cotton back in the
mid-1700s. Cotton, however, was not an important crop at first.
That’s because the kind of cotton that grows best in the American
South is filled with sticky green seeds. Those seeds had to be
removed before the cotton could be used. At that time, it took a
single person a whole day to clean the seeds from just one pound
of cotton. This increased the cost of Southern cotton a great deal.
So most makers of cotton goods looked to other parts of the
world for their supply of raw cotton.
In 1793, Eli Whitney, a young New Englander who liked to tinker
with machines and solve problems, changed all that. That year,
Whitney visited a Georgia plantation. The owner of the plantation
showed Whitney some freshly picked cotton, complete with green
seeds. She suggested that he
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