djfish's studio

1/27/2009

Tuesday Conversation

After i got a call from juan, we went to Cafe to have a lunch social with Shiela.

A kind UK old lady.It's the first time i joined this group.we talked about the rivers in the Sheffied.There are five main rivers here.The Don is the main river, others are streams,branches of Don.Doncaster is named after the Don,like Sheffield is named after Shef river.There are a lots of FIELD kind city names.'Field' means piece of land cleared of trees and usually enclosed,usually has grass around. And 'Caster' is a Roman word,means castle. Chester is also a word from Rome.like Manchester.

later,we talked about the chess and Chinese chess.I didn't think about their relations before untill i showed Shiela the rule of the Chinese
chess and compared with the chess. Actually, it's quite similar,especially,when you know how to play one of them.The Chinese
chess uses the point,and the chess uses the block.

When i came back to my room,I think maybe the main difference between them is the pawn's 'destiny'.In Chinese chess,the pawn is always the
bottom never getback,just go till the end of the boundry.In chess,after the pawn reached the end, it should be converted to other
characters:the knight,rook,bishop,not a pawn any more.What dose it mean? dose it indicate that you can change your life when you reached
you last goal?

A pawn's life is just like person's,which has different role during the whole life.At different stage,you have different abilities.

1/22/2009

[Simulink]variables transfer

send data in the block out:use 'simout' to write data to MATLAB workspace.
receive data out of the block in:use 'constant' to get data from MATLAB workspace.
Details:
simout:
LIBRARY:Sinks
The To Workspace block inputs a signal and writes the signal data to the MATLAB workspace. The block writes the data to an array or structure that has the name specified by the block's Variable name parameter. The Save format parameter determines the output format.
USE:write the variable name in Toworkspace parameters->value name
constant:
LIBRARY:Source
USE:write the variable name in Constant parameters->Main->Constant value

1/15/2009

kungfu panda

1.一切早已注定。

There are no accidents.


2.何必躲呢,躲不过的。

One meets its destiny on the road he takes to avoid it

3.着急的时候脑子也乱了,静下心来就好了。

Your mind is like this water, my friend , when it is agitated ,it becomes difficult to see ,but if you allow it to settle, the answer becomes clear.

4.做不做呢,要不要呢?


Quit don’t quit. Noodles don’t noodles.


5.俗语说,既往者之不鉴,来者尤可追!那就是为什么今天是present(现在/礼物)

There is a saying, Yesterday is history,Tomorrow is a mystery,But today is a gift, That is why it’s called the present (the gift)

6.乌龟:是的,看着这棵树,我不能让树为我开花,也不能让它提前结果

Yes ,look at this tree Chivu(师傅) I can not make it boloosm and suits me ,nor make it bear food before it’s time .

师傅:但有些事情我们可以控制,我可以控制果实何时坠落,我还可以控制在何处播种,那可不是幻觉 大师

but there are things we can control,I can control when the fruit will fall... And I can control,What time to seed,That is not illusion , Master

乌龟:是啊 不过无论你做了什么,那个种子还是会长成桃树,你可能想要苹果 或桔子,可你只能得到桃子,那个种子还是会长成桃树

Yes, but no matter what you do,That seed will grow to be a peach tree,You may wish for an Apple or an orange,But you will get a peach

师傅:可桃子不能打败太郎

But peache can not defeate Tai Long

乌龟:也许它可以的 ,如果你愿意引导它、滋养它、相信它。

Maybe it can if you are willing to guide it , to nuture it , to believe in it .

7. 阿宝,天不遂人愿,况且这本不是天意,阿宝,忘了其它的事情,你的使命一直都在向你召唤。我们是面条家族,血管中流着这样的血。

I'm sorry things didn’t work out …,It’s just what it’s meant to be,Paul ,forget everything else ,your destiny still awaits.

We are Noodle folk,Broth runs deep through our veins

8.你不能走,真的武士决不会退却

you cannot leave ,real warrior never quits.

9.师傅:那你为什么不退出呢?你知道我一直想把你赶走,可你还是留下来了。

Why didn’t you quit ? you know I was trying to get rid of you,but you stayed

阿宝:是啊,我留下来了。我留下来是因为每次你往我头上丢砖头,或说我难闻,这很伤我的心。可最伤我心的是,我每天努力练习,却还是这个我。

我留下来,因为我以为,如果还有人能改变我,能让我焕然一新,那就是你--中国最伟大的功夫师父!

Yes ,I stayed .I stayed ,because every time you threw up brick on the head,or said I smelled ,it hurts.But it could never hurt more than I did everyday in my life just being me .

I stayed ,because I thought ..If anyone could change me ,could make me not me ,it was you,the greatest Kong Fu teacher in the whole of China!

10,罗嗦什么,打吧!

Enough talk~ let's fight!

11、牛人不收费,迷死人不偿命~

There'e no charge for awesomeness or to attractiveness !!

12.我私家汤的绝密食材,就是…什么都没有。

The secret ingredient of my secret ingredient soup is...nothing.

13. 你说它特别,它就特别了。

To make something special ,you just have to believe it’s special.

Ten love sentences[zt]

track from:http://hi.baidu.com/kevin82418/blog/item/a83990643bbb41f3f63654af.html
1) I love you not because of who you are, but because of who I am when I am with you.

我爱你,不是因为你是一个怎样的人,而是因为我喜欢与你在一起时的感觉。

2) No man or woman is worth your tears, and the one who is, won't make you cry.

没有人值得你流泪,值得让你这么做的人不会让你哭泣。

3) The worst way to miss someone is to be sitting right beside them knowing you can't have them.

失去某人,最糟糕的莫过于,他近在身旁,却犹如远在天边。

4) Never frown, even when you are sad, because you never know who is falling in love with your smile.

纵然伤心,也不要愁眉不展,因为你不知是谁会爱上你的笑容。

5) To the world you may be one person, but to one person you may be the world.

对于世界而言,你是一个人;但是对于某个人,你是他的整个世界。

6) Don't waste your time on a man/woman, who isn't willing to waste their time on you.

不要为那些不愿在你身上花费时间的人而浪费你的时间。

7) Just because someone doesn't love you the way you want them to, doesn't mean they don‘t love you with all they have.

爱你的人如果没有按你所希望的方式来爱你,那并不代表他们没有全心全意地爱你。

8) Don't try so hard, the best things come when you least expect them to.

不要着急,最好的总会在最不经意的时候出现。

9) Maybe God wants us to meet a few wrong people before meeting the
right one, so that when we finally meet the person, we will know how to
be grateful.

在遇到梦中人之前,上天也许会安排我们先遇到别的人;在我们终于遇见心仪的人时,便应当心存感激。

10) Don't cry because it is over, smile because it happened

不要因为结束而哭泣,微笑吧,为你的曾经拥有。

1/05/2009

Biot–Savart law[zt]

Aerodynamics applications

The Biot-Savart law is also used to calculate the velocity induced by vortex lines in aerodynamic theory.

In the aerodynamic application, the roles of vorticity and current are reversed as when compared to the magnetic application.

In Maxwell's 1861 paper 'On Physical Lines of Force', magnetic field strength H was directly equated with pure vorticity (spin), whereas B was a weighted vorticity that was weighted for the density of the vortex sea. Maxwell considered magnetic permeability μ to be a measure of the density of the vortex sea. Hence the relationship,

(1) Magnetic Induction Current

\mathbf{B} = \mu \mathbf{H}

was essentially a rotational analogy to the linear electric current relationship,

(2) Electric Convection Current

\mathbf{J} = \rho \mathbf{v}

where ρ is electric charge density. B was seen as a kind of magnetic current of vortices aligned in their axial planes, with H being the circumferential velocity of the vortices.

The electric current equation can be viewed as a convective current of electric charge that involves linear motion. By analogy, the magnetic equation is an inductive current involving spin. There is no linear motion in the inductive current along the direction of the B vector. The magnetic inductive current represents lines of force. In particular, it represents lines of inverse square law force.

In aerodynamics the induced air currents are forming solenoidal rings around a vortex axis that is playing the role that electric current plays in magnetism. This puts the air currents of aerodynamics into the equivalent role of the magnetic induction vector B in electromagnetism.

In electromagnetism the B lines form solenoidal rings around the source electric current, whereas in aerodynamics, the air currents form solenoidal rings around the source vortex axis.

Hence in electromagnetism, the vortex plays the role of 'effect' whereas in aerodynamics, the vortex plays the role of 'cause'. Yet when we look at the B lines in isolation, we see exactly the aerodynamic scenario in so much as that B is the vortex axis and H is the circumferential velocity as in Maxwell's 1861 paper.

For a vortex line of infinite length, the induced velocity at a point is given by

v = \frac{\Gamma}{2\pi d}

where

Γ is the strength of the vortex
d is the perpendicular distance between the point and the vortex line.

This is a limiting case of the formula for vortex segments of finite length:

v = \frac{\Gamma}{4 \pi d} \left[\cos A + \cos B \right]

where A and B are the (signed) angles between the line and the two ends of the segment.

track back:http://en.wikipedia.org/wiki/Biot-Savart_law


basic terminology associated with rotorcraft

1.advance ratio,μ=V/ΩR typically μ<=4
V:forward flight speed
Ω:angular speed of the rotor
R:rotor radius
2.blade azimuth ψ
the angle that the blade makes with the horizontal axis
3.the advancing blade side
rotor blade moves in the same direction as the forward flight speed
4.the retreating blade side
the blade moves in a direction opposite to the direction of flight
5.trim
the process of balancing the forces and moments
6.cyclic pitch
the angle of attack of the blades on the advancing and retreating sides must be adjusted periodically throughout each blade rotation cycle so that there is a balance of rolling moment
7.trimmed
after cyclic pitch the rotor is said to be trimmed
8.collective pitch
a control in which the angle of attack of each of the blades is increased simultaneously to achieve a higher lift;for a hovering rotor,an increse of the collective pitch,for example,results in climb
9.form drag
that part of the drag on an aerofoil which arises from its shape. It varies according to the angle of attack and can be decreased by streamlining
10.viscous drag
That part of the rearward force on an aircraft that results from the aircraft carrying air forward with it through viscous adherence
11.induced drag
in situations where loads are generated by three-dimensional vortex systems,the pressure drag is usually called induced drag
12.BVI
blade vortex interaction
13.coefficients
the major design parameters for the helicopter are the dimensionless coefficients related to thrust andpower
thrust coefficient Ct
torque coefficient Cq
power coefficient Cp
figure of merit FM

1/03/2009

The Feasibility of an Aerospace Engineering Career[zt]

The Feasibility of an Aerospace Engineering Career

The Feasibility of an Aerospace Engineering Career


by
Derek Bridges
June 18, 1998


Abstract


Aerospace engineering is an exciting, demanding, and
dynamic career. Dealing with everything from aircraft and spacecraft to
cars and ships, aerospace engineers perform a variety of tasks,
including research, design, testing, maintenance, teaching, and
management.


Requirements for aerospace engineering fall into
three categories: education, professional organizations, and skills.
While most engineers complete graduate and post-graduate study, only a
bachelor's degree is essential. Membership in professional
organizations, relating directly and indirectly to the aerospace
industry, is necessary to stay current in such a fast-changing field.
In addition, engineers must be skilled in three main areas: science,
communication, and teamwork.


Currently, the employment outlook and chances for
advancement in the field are favorable, although engineers may be
required to relocate, work long hours, and travel often. Another
downside is the aerospace industry's 15-year employment cycle, but
these fluctuations are usually offset by fringe benefits.


My interests, experience, and skills closely follow
those needed for aerospace engineering, leading me to conclude that I
would be well suited for a career in the industry. However, I can
improve my prospects by continuing my education and improving my
network of contacts in professional organizations.


Introduction


Recent cutbacks in military and space programs have
limited the number of available engineering jobs, especially in the
aerospace industry. However, current projections forecast growth in the
civil aviation and space sectors, increasing the need for aerospace
engineers. Because the past job market had discouraged many engineering
students from aerospace, qualified graduates will find the industry
wanting for workers, both to replace outgoing engineers and to fill the
need created by the new growth (Braddock, "Aerospace Engineers").


As a college student interested in aerospace
engineering, I consulted professionals and relevant literature to learn
about the following areas: roles of aerospace engineers, educational
and professional requirements, skill requirements, employment outlook,
opportunities for advancement, and career advantages and disadvantages.
By comparing these areas with my own education and experience, I am
able to determine the answers to these questions:


  • Is aerospace engineering the best career for me?
  • Am I preparing correctly to enter the field?
  • What other steps should I take before entering the field?
  • What steps should I take to remain current after entering the field?

Discussion of Findings


Position Description


Roles of an Aerospace Engineer


Aerospace engineers work in an extremely diverse field, and as such, they play a large number of different roles:


  • Research – Working in a government, university, or company
    laboratory, engineers investigate problems in specific areas, such as
    aerodynamics, propulsion, or computer modeling.
  • Design – Operating mainly in a corporate setting, teams of
    design engineers develop new aircraft, spacecraft, and engines. Some
    teams also revise existing designs to improve speed or fuel efficiency.
  • Testing – Using equipment including wind tunnels, flight
    simulators, and strain gauges, testing engineers work with research or
    design teams to examine characteristics of vehicles, either in flight
    or mounted on a test stand.
  • Product Support – Coordinating efforts with customers, support engineers provide for maintenance, safety, and efficiency upgrades.
  • Teaching – Acting as a visiting scholar or a member of the
    faculty, many aerospace engineers share their knowledge and experience
    with university students.
  • Management – Leading design or research teams, senior
    engineers with management training supervise budget, personnel, and
    other business matters.

Aside from performing a variety of tasks, aerospace
engineers work on a wide variety of different projects. Most often,
projects fall completely in the aerospace field: aircraft, spacecraft,
and satellites (Braddock, "Aerospace Engineers").
However, aerospace engineers also crossover to participate in other
fields; they work with astronomers, physicists, mechanical engineers,
and marine engineers to help design and build research equipment,
automobiles, and ships (Melton; Undergraduate 41).


Requirements


Education. Aerospace engineering is a highly
technical field, requiring a bachelor's degree for entry-level
positions. For more advanced positions, a graduate degree and
post-graduate work is often necessary. Many aerospace engineers also
obtain bachelor's or higher degrees in other related fields, such as
mathematics, physics, computer science, or materials science. Managing
engineers are required to have business and management training,
preferably a master's in business administration (Melton).


Professional Associations. Because the
aerospace field is dynamic, engineers must belong to at least one
professional organization in order to keep up with current trends. The
American Institute of Aeronautics and Astronautics, or AIAA, has the
broadest membership base, dealing with both aviation and space. Other
smaller groups include the American Helicopter Society, for engineers
specializing in vertical flight, and the American Astronautical
Society, intended for spacecraft designers and space scientists (Melton).


Many aerospace engineers also join societies that
indirectly relate to their area of expertise. The American Society of
Mechanical Engineers and the Society of Automotive Engineers allow for
networking with other engineers and material scientists, while the
American Physical Society and American Chemical Society provide a link
to physicists and chemists (Braddock, "Engineers").


Skills. To succeed in the aerospace industry,
engineers need to be extremely skilled in three main areas: science,
including math and computer science; written, spoken, and graphical
technical communication; and teamwork.


All aerospace engineers use science and math in
their careers. Most important are physics and its related disciplines:
engineering mechanics, thermodynamics, and aerodynamics. Math,
including differential equations and statistics, is also essential, as
it is an integral part of the other scientific fields. Other
significant sciences include chemistry, for those engineers working
with advanced ceramics and composite materials, and computer science,
needed to build computer models and simulations, mainly using the
Fortran and C++ computer languages (Melton).


Aerospace engineering requires accurate and precise
technical communication. Writing skills are necessary in composing
specifications, research proposals, and technical reports, while
speaking and presentation experience becomes essential, both for formal
meetings and conferences and informal discussions (Melton).
As with any other engineering profession, interpreting graphical
information, such as graphs, charts, and production drawings, is vital
to understand how parts fit together or what a certain data set
represents (Undergraduate 40).


Since no aerospace engineer works alone, teamwork
skills are absolutely fundamental. While working in a team, an engineer
must be receptive to each member, considering each person's thoughts
and ideas and judging them based on their own merits. Special
consideration must be given when dealing with international issues,
taking care to respect each group's customs and culture (Melton).


On-the-Job Reality


Employment Outlook and Advancement Opportunities


Despite recent cutbacks in military budgets and a
number of mergers between large aerospace corporations, the demand for
aerospace engineers continues to grow, although more slowly than the
average. Most growth will occur in the space and civil aviation
sectors, although all areas will have openings to replace engineers who
move to other positions or retire.


While aerospace companies have facilities all over
the nation, most job opportunities are concentrated in the South and
West, especially California, Washington, Texas, and Florida. Outside of
the United States, there are also a large number of aerospace firms;
however, only Europe's Airbus is as large as the American corporations ("Aerospace Jobs on the Rise").


Once in the aerospace industry, engineers have great
potential for advancement when compared with other engineering
specialties (as shown in Figure 1).
After gaining experience as a member of a research or design team, an
engineer may be promoted to a larger, more complex project. Following
that, further promotions may bring a supervisory post, or following
further training, which is often funded by the company, a management
assignment.


Advancement could also continue outside of the
company structure. For example, an, engineer may start with an
aerospace firm after graduation, work with them for a period of time,
transfer to a government job with NASA, join a university as a
professor or researcher, and retire as a consultant (Undergraduate 37-38).


Starting and Median Salaries of Some Engineering Fields — Source: Data from Braddock, "Engineers"


Advantages and Disadvantages


Like every occupation, aerospace engineering has its
advantages and disadvantages. As illustrated in Figure 1, the starting
salary for aerospace engineers is comparable to that of other
engineering fields, while the median salary rises above that of the
other fields. In addition to the salary, companies also provide fringe
benefits, such as stock options, health and dental benefits, and
reimbursement for continuing education (
Anderson 9).


Balancing these advantages are the more challenging
and stressful work required of an aerospace engineer, as well as the
large 15-year fluctuations in the job market. For some engineers, a
great deal of travel is essential, especially for those participating
in conferences or conducting flight testing (Melton).


Self-Assessment of Skills


To be successful in an aerospace engineering career,
I must have the skills mentioned above: science, communication, and
teamwork.


I have had a great deal of experience in science and
math. In high school and college, I have earned excellent grades in
physics, chemistry, and calculus. During the next few years, I will be
taking classes in engineering mechanics, thermodynamics, and
aerodynamics.


As for communication, two years experience with
technical writing and three years training in graphical communication,
including computer-aided drafting, will provide a solid basis once I
enter the aerospace industry.


Operating as part of a team is nothing new to me. In
my Engineering Design and Graphics class, I worked with three other
students of varying abilities and motivation to design and build a
working scale within a limited time period. After sharing ideas, we
reached a workable compromise, resulting in a finished product that
operated with only 2% error.


Conclusion


Summary of Findings


Aerospace engineers deal mainly with aircraft and
space vehicles, working in every level of design and production. In
addition to memberships in professional organizations, aerospace
engineers must have at least a bachelor's degree and should be skilled
in science, math, communication, and working as part of a team. Once in
the industry, there are numerous chances for advancement, although they
may require relocation, long work hours, and extensive travel. Taking
these factors into account, a career in aerospace engineering would
suit my interests, abilities, and experience well.


Interpretation of Findings


After comparing all aspects of aerospace engineering
– duties, requirements, and working conditions – with my personal
attributes, including temperament, abilities, and work habits, I have
determined that I would be well-suited to a career in the aerospace
industry. From my literature research and my interview with Dr. Melton,
I learned that graduate school would be the best option to follow after
graduation, so that I can improve my chances for advancement after
entering the workforce. Expanding my education to overlap with another
engineering discipline would add to my aerospace skills, and should
allow me to move between fields, which may be necessary in a dynamic
job market.


Recommendations


In order to plan for aerospace engineering career, I should consider the following advice:


  • Look into opportunities for internships, co-op jobs, and graduate schools.
  • Stay current in the field by preserving professional memberships and contacts.
  • Be flexible when searching for an entry-level job.

Works Cited


"Aerospace Jobs on the Rise." AIAA Student Journal 35.3 (1997): 16-17.

Anderson, Tania. "Lockheed Martin's Crusade for High-Tech Talent." AIAA Student Journal
35.3 (1997): 8-9.

Braddock, Douglas. "Aerospace Engineers." 15 Jan. 1998. 1998-99 Occupational Outlook
Handbook <http://stats.bls.gov/oco/ocos028.htm> (29 May 1998).

Braddock, Douglas. "Engineers." 15 Jan. 1998. 1998-99 Occupational Outlook Handbook
<http://stats.bls.gov/oco/ocos27.htm> (29 May 1998).

Melton, Robert G. Associate Professor of Aerospace Engineering, Penn State University.
Telephone Interview. 8 June 1998.

Undergraduate Curriculum Information Package. University Park, PA: Penn State University, 1998.



Web Formatting - Copyright 2006 Derek Bridges
Last Updated: September 17, 2006
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