Introduction:
Mechanical engineering, the broadest of all Engineering disciplines
deals with design and production of tools, machines and all other
mechanical equipment to be used in industries. The industry offers a
wide choice of options extending across many interdisciplinary
interdependent specialties. Mechanical engineering is concerned with all
types of machinery in industries and
all aspects of their mechanism and functioning; the design, development,
construction, production, installation, operation and maintenance; such
as large steam and gas turbines, components of thermal power stations,
internal combustion engines, jet engines, machine tools, air
conditioning and heating machines, refrigerators etc to name a few. They
not only design and create new products, but also develop materials for
them and ways of making them.
In a way, mechanical engineers
are involved in creating the future. They are the driving force behind
many of our technologies and industrial processes including innovative
products like mobiles, PCs and DVD etc in our modern world. The work of a
Mechanical Engineer can be extremely challenging and fulfilling,
requiring IT, design and analytical skills together with an ability to
work as a team. As their work involves production, transmission and use
of mechanical power and heat, they have to analyse the different
materials used for the machines and their tolerances, investigate the
different energy sources and the power they generate and the design
problems if any. When designing and making a commercial product they
have to take into account all the business and marketing aspects to make
sure that the product is affordable. They share interests with many
other engineers like Civil Engineers in structures and stress analysis;
Electrical engineers in electronics, computing and control theory;
Aeronautical Engineers in fluid flow and turbomachinery etc and also
design tools needed by other engineers for their work. They work as part
of a team with other engineers as well as financial, business and
management professionals on a project together. Mechanical Engineers are
also responsible for maintenance and repair of the devices. Care has to
be taken that the plants give maximum output and the machinery is
properly maintained.
The specialisations include in areas like
thermal engineering, design, and production engineering etc. Mechanical
engineers work mainly in manufacturing firms. They can find work in
administrative and managerial positions in government departments or
public and private sector industries or do research as well as teaching
in Research and teaching institutes. They could also opt for technical
sales / marketing or work as independent consultants.
Job Prospects:
Mechanical Engineering finds applications in all fields of technology.
They could work in many industries including private or public sector
industries of various types, and their work varies by industry and
function. With the rapid rate of expansion in the industrial sector, the
employment potential for mechanical engineers is very high.
In the government sector, freshers could join as Junior Engineers and go
up the ladder as Assistant Engineers, Assistant Executive Engineers,
Executive Engineers, Superintendent Engineers and so on.
These engineers are required in automobile, chemical, electronics, steel
plants, oil exploration and refining, technical wings of armed forces,
space research organisation, etc. Candidates with post graduate degree
or an additional management degree could find work in administrative and
managerial positions in government departments or public and private
sector industries or do research as well as teaching in Research and
teaching institutes. They could also opt for technical sales / marketing
or work as independent consultants. Several government departments
including Posts and Telegraphs, Defense, PWD, and CPWD employ mechanical
engineers. Aeronautical, agricultural, automobile, chemical, and power
plants, as well as the railways, need mechanical engineers to design and
maintain their machinery. In agricultural sector, mechanical engineers
play a vital role by establishing service centres for maintenance of
tractors, oil engines, pump sets, electric motors and other agricultural
equipments.
Mechanical Engineering graduates has several job
opportunities in Marine engineering. After undergoing a basic pre sea
training or studying marine engineering or nautical science course, they
can join as engine cadets, marine engineers or navigating officers.
Mechanical Engineering graduates can also opt for M.E/ M.Tech programmes
in Marine engineering, Petroleum engineering, Aerospace/ Aeronautical
engineering or Nanotechnology.
Remuneration:
The
remuneration and conditions of service depend on the industry and its
function. Those engineers, who choose to work in the private sector,
could negotiate their terms and conditions with the management
themselves.
Most fresh engineers start at Rs 15,000 to Rs 20,000
per month, with allowances. Those with an additional management degree
in addition to engineering can command salaries of Rs 25,000 to Rs
40,000 per month.
In the US, according to a salary survey by
the National Association of Colleges and Employers, bachelor’s degree
candidates in mechanical engineering received starting offers averaging
$48,426 a year, master’s degree candidates had offers averaging $55,994,
and Ph.D. candidates were initially offered $72,096.
The protein DEFB126 acts as a "cloaking device," allowing sperm to swim through mucus and avoid the immune system in order to reach the egg, said Gary Cherr, a professor at the UC Davis Bodega Marine Laboratory and Center for Health and Environment. Cherr is the senior author of the paper.
But the UC Davis researchers found that many men carry a defective gene for DEFB126. A survey of samples from the U.S., United Kingdom and China showed that as many as a quarter of men worldwide carry two copies of the defective gene -- which may significantly affect their fertility.
Infertility affects 10 to 15 percent of the U.S. population, said John Gould, associate professor of urology at UC Davis, who was not involved in the research. About half of those cases involve problems with male fertility.
One of the mysteries of human fertility is that sperm quality and quantity seem to have little do with whether or not a man is fertile, said Ted Tollner, first author of the paper, who carried out the work as a postdoctoral scholar with Cherr. Tollner is now an adjunct assistant professor in the UC Davis Department of Obstetrics and Gynecology.
"In 70 percent of men, you can't explain their infertility on the basis of sperm count and quality," Cherr said. Studies like this may give us opportunities to explain these cases, Gould said.
If the discovery were successfully developed into a test, it could be used to send couples directly to treatment with intracytoplasmic sperm injection or ICSI, in which eggs are removed from the woman and injected directly with sperm, avoiding an expensive workup to exclude other causes, Gould said.
Tollner and Cherr were looking for ways to make contraceptive vaccines when they started looking at DEFB126. The protein belongs to a class of molecules called defensins, natural germ-killers found on mucosal surfaces. DEFB126 is produced in the epididymis, the structure where sperm are stored after they are produced in the testes, and deposited onto sperm in the epididymis to form a thick coat.
Tollner and Cherr were trying to make antibodies to the human protein, without much success. So they enlisted the help of Professor Charles Bevins, an expert on defensins who had just joined the UC Davis Department of Medical Microbiology and Immunology.
Bevins' lab made a recombinant copy of the human DEFB126 gene, with the aim of generating a purified protein that Tollner and Cherr could use to create antibodies. On their first attempt, they found the gene had a mutation that prevented it from making a protein. But when they used sperm from a different donor, they were able to make the normal protein.
"If we hadn't seen this in the first clone, we would be confused to this day," Bevins said.
Sperm from men with the defective DEFB126 genes look normal under a microscope and swim around like normal sperm. But they are far less able to swim through an artificial gel made to resemble human cervical mucus.
When the normal protein is added to the sperm, they recover their normal abilities, the team found.
Working with Edward Hollox at the University of Leicester, England, Xiping Xu at the University of Illinois, Chicago, and Scott Venners at Simon Fraser University, Canada, the researchers were able to look at the frequency of the gene in DNA samples from people in the U.S., United Kingdom, China, Japan and Africa.
They found that worldwide, about half of all men carry one defective copy; a quarter have two defective copies and therefore make sperm that are poor at swimming through mucus.
In collaboration with Xue Liu and other scientists at Anhui Medical University in Anhui, China, the epidemiology team headed by Venners was able to look at the effect of the mutation on a group of couples trying to conceive. They found a statistically significant decrease in the number of pregnancies in couples where the man carried two copies of the defective DEFB126 gene.
Why should a mutation that affects fertility be so astonishingly common? It may be that heterozygotes -- men with one normal and one defective gene, but normal fertility -- are advantaged in some way, Tollner said.
Tollner noted that compared to sperm from monkeys and other mammals, human sperm are typically poor quality, slow-swimming, and with a high rate of defective cells. It's possible that because humans, unlike most mammals, breed in long-term monogamous relationships, sperm quality just does not matter very much, Cherr said.
However, some researchers believe that, for reasons unknown, human male fertility has been falling worldwide in recent decades. That decline might be unmasking the problems associated with the defective DEFB126 gene.
Cherr said that they hope next to work with a major infertility program in the U.S. to further explore the role of the mutation.
Other authors of the paper are: Ashley Yudin and James Overstreet, Center for Health and Environment, and Robert Kays, Tsang Lau, Department of Medical Microbiology and Immunology, UC Davis; and Genfu Tang and Houxun Xing, Anhui Medical University.
The study was funded by grants from the National Science Foundation and the National Institutes of Health.