Saturday, December 26, 2009
MECA wind 05
The New face of Web hosting
It's a safe bet that the Web hosting industry of the future will look very different from the one today's hosting providers are used to, and that's certainly cause enough for concern to those in the business. An even greater concern, though, is the serious possibility that the future isn't as far away as some hosts might believe.
Over the past year, plenty of signs have emerged that indicate the face of Web hosting is already starting to stretch and shift in new directions. And it's not just all the usual suspects of change - i.e., shutdowns, mergers, buyouts, etc. - although there have been plenty of those. No, the new winds of change include acquisitions of companies that deliver more than just additional hosting customers, a fresh generation of startups that look nothing like your father's Web hosting company, and experiments with innovative ways to sell hosting to the next wave of customers.
Consider the growing trend of acquisitions focused on providers of small-business tools and services other than hosting, for example. One of the more recent - and most notable - transactions is Interland's purchase of the Website publishing company Trellix, completed earlier this month. The acquisition arms an already dominant player in the SME (small-and medium-sized enterprise) hosting industry with an even stronger grasp on the market by giving it control over a site-creation tool already used by millions of consumers.
Everyones Internet/Rackshack's buyout of HostingTech Magazine this month also creates unique new marketing opportunities for a veteran hosting provider, putting it at the helm of a recognized trade publication. That's added muscle for a company that also operates a popular hosting industry forum, WebHostingTalk.com.
Of course, there's still plenty of activity in the garden-variety host-to-host acquisition arena, too: 2001 - 2002 saw more M&A headlines than either of the previous two years, and 2003 is showing all signs of that trend continuing.
And then there's the new breed of Web hosts emerging onto the field: ventures like OnSmart Network, ServerBeach or Ready-Set-Web, all squarely focused on the SME market. Ready-Set-Web, started by software R&D company Webnox Corp., roams the furthest into new territory with its "ready-made Websites for rent" and a range of personal-interest and business templates that include domain name registration and regularly updated site content. In promoting its services, Ready-Set-Web barely mentions the word "hosting," much less old-World hosting terms like megabytes or bandwidth.
The future of SME hosting gets even more interesting when you factor in the small-business hosting forays of 'Net service providers like Yahoo! and its "business-class Web hosting service," or AOL, with its AOL for Small Business offering for small-office/home-office customers. Both services, launched late last year, promise to make an already competitive hosting industry even more cutthroat, considering Yahoo!'s and AOL's well established brand-name familiarity with millions of consumers and entrepreneurs.
While "traditional" Web hosts can't help but notice these developments, many haven't yet fully formulated their response plans. They're dead certain they need to do something different to stay in the race for new and existing small-business customers. But they're still fuzzy on the details of what that "something different" is Ö or should be.
Although they're still exploring their long-range strategic options, small-business hosts at least realize they must keep up with the competition as far as value-added services and tools are concerned. That explains the growing number of hosting providers that are expanding their services, implementing automation tools, adding site-design tools or wizards, and making e-commerce a standard offering, even with entry-level plans. And that's a movement guaranteed to pick up steam in coming months.
What else does the near future hold? Look for more Web hosts to forge increasingly creative alliances with complementary service providers, seek out new ways to sweeten their appeal to resellers and affiliates, and experiment with less-traditional means for marketing their services. Among those who have already taken that last step are EarthLink and C I Host, both of which recently began promoting their services through retail storefronts, either on their own or through partnerships.
While no one company has yet shown it has all the answers, for the average host hoping to stay on top of the small-business market in 2003 and beyond, one conclusion is loud and clear: the coming months and years will present challenges like no time before, and it will take creativity and stamina to stand up to the test. The future of Web hosting is here.
Saving time for finding Host
The initiation of a web-site is an awesome proposition. From beginner?s questions such as: ?What?s involved in building a web-site?? to a slightly more-informed, ?Can my ISP give me a price-break for hosting my site?? the issues escalate rapidly to encompass everything from geography to economy. The following information can help prevent common errors and omissions that may cost more than a new player in the cyber-game can afford.
A Plethora of Plenty
In the quest to research web-hosting, information from approximately 200 hosting organizations was surveyed. This is an admittedly small sampling from the millions of organizations extant on the web, but gives a ?toe-hold? on the climb to building and publishing a web-site. These organizations range from ISP (Internet Service Providers) wishing to garner additional receivables, to non-profit organizations who will host private, non-commercial concerns to benefactors and others who agree to have the organization?s web links prominently displayed on the user?s site. Most of the information was redundant and equally unenlightening. Few of the hosting organizations offered any type of ?primer to web-hosting? that would have been beneficial. Likewise, telephone calls to the firms involved were fairly futile. Most were automated response lines that provided canned responses to ?frequently asked questions? (FAQs), or allowed brief messages to be recorded for later call-backs ? although none called back. Evidently, my lack of expertise or knowledge on the issue was an impediment to gaining any knowledge from the knowledgeable!
Despite my early frustrations, I was able to learn a few basics concerning hosting organizations. Most of the data gleaned revolved around choosing a hosting concern that was the epitome of reliability; (which, of course, all of them claim to be) and all provide prodigious statistics concerning their lack of ?down time.?
Reliability the Name of the Game
One of the most important factors in terms of any website?s operational impact is inextricably tied to the host?s reliability: the web host must provide reliable servers - look to specific uptime guarantees. Additionally, an investigation into what options the host offers the client with respect to obtaining technical support is indicated.
It seems that most web hosts should be able provide a basic website presence from a technical/availability standpoint. This is dependent on their in-house assets such as number and types of servers, backbone (network) construction and configuration, as well as types of software in use. To reiterate, one?s focus should be on the reliability of the hosting company to make sure that the hostee?s (client?s) "key information" is always online without downtime.
Even though, with a basic web site, initial hosting needs may be simple, sufficient growth should be planned to allow for a scale-up to a larger hosting package. Options should be discussed with the host to determine the availability for additional site space as future needs dictate.
Is Anyone Home?
The Technical Support Element One must also be sure that a self-designed website has adequate in-house technical support to maintain and upgrade the site as requirements change. Commercial web-site development software should be considered to simplify and benchmark the process. If this is the case, the potential web host must have the ability to support all of the programs to be used. In this matter, the types of communication expected between the host and client should be discussed: for issues of moderate importance, it may be sufficient to communicate via e-mail; for urgent matters (such as server outage or other technical issues that take the site down), there must be clearly defined avenues whereby host and client can communicate real-time. In any event, it is wise to know the average response time you can expect to a query initiated by the client.
In planning a website, consider the potential uses of the website and the interactivity that users will be involved with, e.g., is it reasonable at this time to expect the website to have only a low bandwidth usage? If so, many "starter" packages offer sufficient bandwidth for an initial foray into cyberspace. Again, with growth in mind, a potential host should be asked how easily "additional bandwidth" can be added to the hosting package if site traffic grows more rapidly than expected.
Be It Ever So Humble:
The Question of Off-shore Hosts In an earlier paragraph, geography was mentioned as a concern to be addressed. Regional differences are generally unimportant in cyberspace; however, many off-shore concerns offer attractive packages for website hosting. Before contracting with an off-shore firm, be sure to pursue due diligence in the selection process. Many such concerns may not be able to provide the guarantees or assurances required to entrust them with e-commerce. Many countries have yet to even enact laws concerning web-fraud, e-commerce piracy, or otherwise protect the clients of such firms.
It would most likely be desirable to host the site with a local provider. This may be beneficial provided the local host has sufficient network operations for speed and reliability purposes. Working closely with a local provider could provide many benefits: they may be able to provide most customized solutions than other providers; they may be more easily accessible and amenable to change orders; and they may have a vested interest in keeping the client?s e-commerce ?close to home.?
In terms of economy, however, one might wish to consider a national or international web host, as more specialized, large hosting companies often offer more dollar value within their hosting packages. In any event, it is supremely important to make sure that ?due diligence? is pursued before making any decisions about off-shore hosts; it would be tragic to discover, after the fact, that it may be as illegal to offer a particular product in your hosting country as it is, for example, to import Cuban cigars to the US.
Don?t think that hosting your company off-shore will prevent the tax man from coming, either. US citizens are subject to taxation on ?all income, from whatever source, unless specifically excluded by law.? (Internal Revenue Code § 63) Have any hosting agreement checked by an attorney specializing in off-shore businesses before committing contractually to the agreement.
Web hosting for small bussiness
Outsourcing has gained popularity over the last few years as companies around the globe have turned to outside experts to deploy sound technology strategies. Once reserved for larger companies, outsourcing is now viewed as a cost-effective alternative to in-house solutions for companies of all sizes. Recent findings from market research firm The Yankee Group found that over 50 percent of small to medium-sized businesses (SMB) now employ some type of outsourcing to fulfill their information technology (IT) needs.
As the trend toward outsourcing moves into the SMB market, small companies are learning to leverage technology to streamline business operations and automate their business processes to create greater efficiencies. One of the main reasons that SMBs are increasing their use of outsourcing services is to help lift the burden from already-taxed IT staff. According to The Yankee Group, the ratio of IT staff support to personal computers in small businesses is 1:25, while medium-sized businesses have a ratio of 1:33. In fact, some small businesses ñ 29 percent of very small businesses ñ have no full time IT staffs at all, according to Yankee.
One of the fastest growing segments of SMB outsourcing is that of Web hosting. A growing percentage of companies are turning to outsourced Web hosting solutions to ensure that their Web site is secure, reliable and scalable. In fact, analyst firm Aberdeen Group predicts that the percentage of SMBs opting for Web hosting services will grow from 40 percent today to more than 70 percent in 2004 (Network Computing, September 3, 2001).
The SMB market is an important market segment in todayís economy and is expected to grow significantly over the next three to five years,î said IDC Web hosting analyst Melanie Posey. ìThe demand for more complex Web site functionality, ever-escalating costs and greater outsourcing benefits will further spur outsourced hosting among SMBs.
Outsourcing: The bottom line
As SMBs evaluate the shift to an outsourced Web hosting model, Total Cost of Ownership (TCO) is often viewed as a major benefit of outsourcing. For SMBs, establishing their own hosting capabilities internally often is a larger investment than outsourcing. The TCO of self-managing a Web site is generally higher due to the costs of an in-house IT staff whose primary responsibility is to manage the Web site. In addition, TCO also factors in the equipment, software, and initial set up costs, as well as the periodic upgrading of equipment, 24/7 help desk services and around-the-clock monitoring and management.
Given todayís economic conditions, a reduction in capital expenditures is a key consideration for any business. By leveraging a Web hosting providerís data center infrastructure, network and expertise, companies can expect a 25 to 80 percent cost savings over in-house solutions. Outsourcing enables a company to reduce its TCO by freeing assets, such as cash that is allocated to capital expenditures and the expense of specially-trained staff, which can account for anywhere from 22 percent to 47 percent of the total budget for the Web site.
The benefits of using a hosting service provider (HSP) go beyond a reduced TCO. While an HSP enables small businesses to get connected to the Web quickly and efficiently, it also provides a strong assurance for a reliable e-commerce platform and provides end-to-end accountability for the performance of a site.
Today, there are a variety of hosting options available to SMBs from a $20 simple hosting set-up, which provides a Web site and a domain name, to fully-managed hosting solutions that provide everything from security to monitoring and reporting. By outsourcing all Web hosting functions to a qualified provider, an SMB is truly able to take advantage of the efficiency and functionality of the Internet to enable and grow its business.
SMBs can also pick and choose what value-added services they need to address Web site performance, business continuity and access challenges. HSPs offer a host of solutions to meet user requirements including monitoring and reporting of site traffic, disaster recovery planning, security threat monitoring, server backup and data storage and retrieval capabilities. In addition, providers usually offer Service Level Agreement guarantees to ensure full-time availability and back-up for the site.
However, if an SMB self-manages its site, there is no recourse if the site goes down, nor any guarantee that it will work. This reliability becomes even more crucial when the Web site is an e-commerce site responsible for driving sales and communicating with potential customers.
Web hosting: The foundation of e-business
As a sales tool, SMBs are discovering what the Web can do for them, giving them access to new regional, national and global markets. With a secure, reliable Web site to market and sell their products or services, or to make their business operations more efficient and streamlined, SMEs can experience the same benefits as their larger competitors.
One example of a small business using the Internet to grow its business is Boston-based LifeClips, Inc., www.lifeclips.com. The company, which converts videotapes to DVDs as a way for consumers to preserve their home video memories, chose the Web to create a new way to reach customers and prospects.
In order to take its business online, and expand its customer base, LifeClips required a Web site that would be highly available, anytime of the day or night. However, managing the data center infrastructure, operating system and applications was far more complex than the company could handle with a small staff of 35. LifeClips turned to a Web hosting provider that could fully manage and maintain its Web site operations, allowing LifeClips to focus on their core business.
Because a significant part of LifeClipsí business comes from online sales and its customer base was more than doubling every month, the company found that an outsourced Web hosting solution provided the essential Internet infrastructure for its online success.
The future of small business Web hosting
As small businesses begin to automate their internal processes and develop online e-commerce capabilities, their Web sites need to deliver top-notch performance. With the increasing importance of small business Web sites and online-enabled functions, itís critical that the Web operations of SMBs be properly managed and supported to ensure their success. Outsourcing Web hosting services can provide that kind of support while helping businesses to decrease costs and increase productivity and their bottom line.
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Sunday, December 20, 2009
SCOPE OF MECHANICAL ENGINEERING
Mechanical engineering is one of the major activities in engineering profession and its principles are involved in the design, study, development and construction of nearly all of the physical devices and system. Continued research and development has led to better machines and processes helping the mankind.
The department of mechanical engineering at IIT Madras is as old as the Institute itself. Its impact on the Institute and on society itself is easily demonstrated by noting the alignment of the department's evolution with key events and technological advances in the India and elsewhere. Today, the department of mechanical engineering of IIT Madras attracts and features an extraordinary rich diversity and quantity of talented individuals, with nearly 700 undergraduates, 500 graduate students and over 50 faculty members. The impressive array of students makes the department as the largest in the country and one of the largest in Asia.
Apart from undergraduate activities which mainly consist of teaching, the faculty of mechanical engineering actively pursues research through graduate students. The current graduate students include nearly 150 Master of Technology students (M.Tech), 100 Master of Science (by research) students (M.S.) and 220 students pursuing their doctoral programme (Ph.D).
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M-Tech
The 4-Semester M.Tech programme is based on the credit system which provides wider choice of courses in the form of electives. The programme consists of four semesters. The first two semesters consist of course work. In the third semester, the students are required to do two courses and carry out their project work in the remaining period. The fourth semester is fully devoted to the project work. The courses are divided as core (compulsory) and electives. M.Tech students are selected based on their choice and GATE score. Candidates with a valid GATE score are eligible to get HTTA (half time teaching assistantship). In addition, candidates sponsored under Quality Improvement Programme (QIP) are also eligible to get scholarship. Apart from these channels, there are number of candidates from industry and defense who join as sponsored candidates.
The students with valid GATE score are admitted into three streams; namely, design, manufacturing and thermal streams. Each stream has common first semester course work. At the end of first semester, the students are allotted specializations of that stream based on his/her choice and first semester marks.
The topic of the research project for his/her project work is selected in consultation with the guide. A duly constituted committee periodically reviews the progress of the work carried out by the students.
Students are divided into small groups based on their selected area of specialization and each group will have a Departmental Faculty Adviser. The Faculty Adviser advises them on all Academic matters including selection of elective courses. The Faculty Advisor functions under the guidance of their respective Departmental Heads.
Dual Degree
Dual Degree is a five year program in which the b-tech course and a specialized m-tech course are integrated together.A comprehensive coverage of all aspects of Mechanical Engineering will be provided in the first three years of the dual degree course. The area of specialization is allocated at the end of the third year on the basis of the availability of seats and preferance and performance of the students. Both b-tech and m-tech in the specialized course will be awarded to the candidate after the successful completion of the course.
Mechanical Engineering Department at IIT Madras offers the following three M-tech specializations in Dual Degree program:
Mechanical Engineering with Specialization in Energy Technology in M.tech.:
The Energy Technology stream blends with basic Mechanical Engineering in the first six semesters. From the seventh semester, courses pertaining to energy technology such as Design and Optimizatoin of Energy Systems, Advanced Energy Technologies, Fundamentals of Combusution, Thermal Energy Conservation, Non conventional Energy Sources and Energy and Environment are included in the curriculum.The curruclum ensures that all aspects of energy technology namely sources, generation, conservation, and pollution control strategies are covered. The final year project involves an in-depth study of specific problem of current interest in energy technology. The course has been designed in such a way that the candidates will be able to take up both R & D and managerial jobs in the energy sector, that typically include research laboratories, government agencies, power generation and distribution companies and consulting firms.
Mechanical Engineering with Specialization in Intelligent Manufacturing in M.tech.:
The course along with basic mechanical engineering covers present day present day manufacturing requirements like precision, repeatability and quality to satisfy the customer needs at an affordable cost. A thorough knowledge update on computer based technologies is needed to achieve the above goal. With this in view, CAD/CAM, Advanced Material removal Techniques, Microprocessors, Controllers, Sensors for Intelligent Manufacturing systems, Networking procedures, Expert systems and Artificial Intelligence, Flexible Manufacturing systems, Mechatronics, Computer aided quality Evaluation, Management Information Systems, etc. are the areas that will be covered under various courses in Intelligent Manufacturing.
Mechanical Engineering with Specialization in Product Design in M.tech.:
This specialization is aimed at enabling the students to imbibe the essence of holistic approach to the design of a product so that there is integrity in form, function, and use. The courses cover Product Engineering, Design Synthesis, Design of Mechnical systems, stress and Compliance in Mechane elements, Ergonomics and aesthetics, Mechatronics, CAD/CAM for product design etc... The project can be taken up in the following areas: Design and Development of Mechanisms, Machines/Mechanical Systems, New products, Development of CAD software for Equipment and System design.
B-Tech
Learn All About Bevel Gears
Intersecting but coplanar shafts connected by gears are called bevel gears. This arrangement is known as bevel gearing. Straight bevel gears can be used on shafts at any angle, but right angle is the most common. Bevel Gears have conical blanks. The teeth of straight bevel gears are tapered in both thickness and tooth height.
Spiral Bevel gears
In these Spiral Bevel gears, the teeth are oblique. Spiral Bevel gears are quieter and can take up more load as compared to straight bevel gears.
Zero Bevel gear
Zero Bevel gears are similar to straight bevel gears, but their teeth are curved lengthwise. These curved teeth of zero bevel gears are arranged in a manner that the effective spiral angle is zero.
What is a Spur Gear?
Parallel and co-planer shafts connected by gears are called spur gears. The arrangement is called spur gearing.
Spur gears have straight teeth and are parallel to the axis of the wheel. Spur gears are the most common type of gears. The advantages of spur gears is their simplicity in design, economy of manufacture and maintenance, and absence of end thrust. They impose only radial loads on the bearings.
Spur gears are known as slow speed gears. If noise is not a serious design problem, spur gears can be used at almost any speed.
A common arrangement of spur gears is an external gear and pinion combination. If the centre distance has to be reduced, then internal gear and external pinion combination is used.
A Gearbox Is Used in Turbines, Windmills, Grinders...
Gears are used for increasing the torque of the source of rotary motion having high angular momentum and low torque. This high torque is necessary for performance of work. This phenomenon of increase in torque is called gear reduction and is brought about by coupling of a smaller gear called the pinion with a larger gear. This results in reduction of torque at the expense of angular momentum. Such a gearbox is called a reducer. One more application of gears is to change the axis or plane of rotary motion with or without gear reduction.
When you open a gearbox you will see that the inner construction is very simple. Inside you will find two gears coupled with one another. The gears may be of spur, helical, cycloid, worm or bevel type. In case of gear reduction, the diameter of the output is larger than that of the input gear. If only a change in direction is required, the size of the gears is the same. Spur gears are used for heavy load but are noisy. If the load is comparatively lesser, helical gears are preferred as they are silent in operation due to gradual engagement. If change of plane of rotation is required, hypoid gears are used.
The gear may be either of metal or plastic. This entire arrangement is enclosed in metallic or plastic housing. The point of contact of the gear teeth is well lubricated with gear oil. The gear oil must be very clean and free of abrasive materials to avoid wearing of the gears.
A gearbox is used in turbines, windmills, grinders, etc. to change the direction of the rotary motion. In automobiles a gear box is used for transfer of to power of the engine to the wheels through a differential.
A Gear Pump Is a Rotary Pump With Positive Displacement.
The gear pump is an example of rotary pump. It is a positive displacement pump in which the pumping action is caused by the relative movement of rotating and stationary element of the pump. The gear pump draws the fluid from a chamber and can attain discharge pressure up to 200 atm. It contains no check valves and when built of proper material can be used for any liquid without suspended solids or abrasives. An efficiency of about 90% can be obtained with this pump.
Construction
The gear pump consists of two identical intermeshing gears rotating with close clearance inside suitable pump housing. One of the gears called the driver gear is connected to the input by a driver shaft. The other gear called the idler gear is mounted on a pin and is free to rotate around the axis of the pin. Power is supplied to the driver gear while the idler gear rotates relatively due to the close intermeshing. The pump is provided with airtight inlet and outlet pipes.
Working
When the pump is operated the driver gear rotates and rives the idler gear and the movement pushes the liquid out of the chamber due to the differential pressure created on either side of the pump.
During operation vacuum spaces are formed as each pair of meshing teeth separates and atmospheric pressure forces the liquid inward to fill the gap. The liquid filling the space between two adjacent teeth is carried along with the teeth as they rotate and is forced out through the discharge opening. The liquid being pumped cannot short circuit back because of the close intermeshing of the two gears.
Advantages
The advantages of this pump are low cost, simplicity in design and construction, uniform flow of fluid, silent operation and low maintenance cost. The only disadvantage is that the pump cannot be used for fluid with solid particles in theM.
Spider Gears Provide Open Differential With Greater Performance
Spider gears are an integral part of you differential. They are part of the gear set that allows your rear wheels to turn at different speeds, which is necessary for many instances. When your vehicle goes into a turn, the out wheel turns at a faster rate than the inner wheel; this is accomplished through a series of gears including spider gears.
Spider gears offer you the ability to turn your vehicle without feeling the rear end bump as you go around a turn. If it weren't for spider gears and side gears within the differential, both rear wheels would turn at the same speed. If you're only going straight, this is not a bad thing, but the moment you go into a turn, the outside wheel will try to speed up. If spider gears and side gears where not in place, that outer wheel would not be able to turn faster than the inner wheel and would actually drag as you went through the turn, producing a bumping, lurching motion.
Spider gears are provided in the differential from the manufacturer and are one of the many shapes that gears can come in. Unlike spur gears, spider gears meet the shaft or other gear at a right angle, allowing them to be seated on shafts that do not touch and allowing the differential to be smaller and yet provide the necessary performance for most applications. Aftermarket, or performance differentials, have differently sized spider gears as well as differential housing to provide better traction for harder usage.
Spider gears are employed in limited slip differentials as well as standard differentials. Within a limited slip differential, spider gears work in conjunction with clutch packs to reduce the speed of a wheel that is spinning much faster than the other. The purpose of the clutch packs is an attempt to keep both rear wheels at relatively the same speed. Their efforts aren't noticeable when you're simply taking a curve, but if one wheel where to be placed on ice or in slick mud, the opposite wheel would be able to grip the road.
A standard differential allows all the torque to go to the wheel with the least amount of resistance; while this isn't a bad thing for street driving, if you intend to take your vehicle off road, or consistently drive in areas where little traction and slick spots are common, a limited slip differential, or fully locking differential is a better choice. The spider gears within these differentials are much larger and made much thicker than they are within standard differentials. With a standard differential, the wheel that has the least amount of traction will get the largest amount of spin, leaving your vehicle sitting still. A limited slip differential is designed to stop that, allowing much more torque to go to the wheel with traction.
Spider gears are one of the modern innovations that allow limited slip differentials to operate. Interestingly, they also play a vital role in locking differentials and standard differentials, as well.
Worm Gear Drives: Quiet, Efficient Performance
Worm gear drives offer many benefits. They take up little space, offer quiet operation and have been used in many different applications. Worm gear drives provide extreme benefits where size is a problem Traditional spur gears would take up considerably more room than what can be accomplished with a simple worm gearbox. They also take advantage of all the major forms of gearing to suit almost any application.
Worm gear drives offer great operation for many different uses. You'll find them in use in use in the mining industry, in ship's rudders and all types of presses. Worm drives offer a great way to amplify a limited amount of torque, though heat can cause them to become less efficient. Worm gears are also used in a limited amount of automotive differentials, though it has fallen out of favor with many manufacturers. Hummer is one of the manufacturers that still utilizes worm gears in their differential, specifically their military vehicles, though some civilian applications have worm gears, as well.
Worm gears were replaced in open differential due to problems with reduction ratios, though many all wheel drive vehicles continue to use worm gear drives in their applications. Large trucks used for hauling very heavy loads often utilize worm gear drives in their differentials, though they require very large differential housings to accommodate the amount of differential fluid needed to dissipate the heat created by the worm gear drive itself.
A worm gear drive consists of two main parts: the worm gear itself, which looks much like a spur gear and the worm, which is a gear shaped like a screw. The benefits that a worm gear drive offers are due to the fact that each revolution of the worm turns the worm gear a whole tooth; this allows them to greatly amplify torque in their relative settings.
Possibly the single best example of a worm gear is the adjustable screw clamp, called a jubilee clamp. These are found almost everywhere and most people are familiar with their appearance. Other forms of the worm gear drive exist, but this is the single most recognizable form that they take. The best applications for a worm gear drive are those in manufacturing industries where greater torque, in a smaller package is required. Since the worm gear drive is able to be set up at right angles to the input shaft, the length of the equipment is significantly reduced. Many industries find that the non-reversible motion is a great benefit, as well. Since the worm can only drive the gear, it means that they can only be used as speed reducers, rather than speed enhancers. The gear cannot drive the worm in a worm gear drive.
Due to these factors, they are an ideal way of decreasing speed, yet increasing power in smaller equipment. While there are many different applications for worm gear drives around the world today, small electric motors are possibly the area that they benefit the most, though musical instruments have been the longest running beneficiary of these devices.
Getting It Right -- Gear Ratio
The gear ratio of your transmission, timing belt/chain and even your analog clock are what is responsible for rotational movement and the speed each piece or part achieves. Setting the correct gear ratio is vital, especially in the automotive industry. The wrong gear ratio will rob you of power, performance and even keep your vehicle from running at all, in the case of a timing belt of chain.
If you've ever seen two gears working together, one turning the other as the teeth of the two gears mesh, you've seen a perfect example of gear ratio. This complex sounding conundrum is nothing more complex and complicated than the teeth of two gears meshing as they turn. It can also mean two sprockets connected with a chain or two pulleys with a drive belt. The best example of the sprockets and chain combination is probably the standard timing chain. This vital piece of engineering is the driving force behind most modern vehicles, though timing belts are still used by some manufacturers.
A correct gear ratio is the driving force behind anything that contains rotational motion. Engines, transmissions, clocks and even windup toys use gears with the correct gear ratio to produce the motion needed to turn whatever needs to be turned. Whether it's belts and drive shafts or tiny plastic axles and wheels, the correct gear ratio is incredibly important. One of the best examples of getting the correct gear ratio would be replacing a timing belt. If the proper teeth are not selected when putting the new timing belt back on, the vehicle will be out of time. In short, it will run either very poorly, or not at all. That's because the pulleys and gears must meet at exactly the right point for the rotation to match. If the rotational speed of the gears or pulleys doesn't match then you have the incorrect gear ratio.
Gear ratio is also used to increase the speed of gears and pulleys. If you have a large gear turning a smaller gear, the gear ratio will increase the rotational speed of the small gear or pulley, dramatically. A gear ratio is written as any mathematical ratio: 2:1, 3:2, etc. In an example, if the large pulley rotated once per every two revolutions of the small pulley, you would have a gear ratio of 2:1. Gear ratio is an observable factor, as well; look under your hood sometime, or inside a clock or anything else containing gears; you'll see that larger pulleys and gears usually turn more slowly than their smaller counterparts. This knowledge is used to create high speeds within engines and transmissions.
Gear ratio and teeth on the gears are inextricably related. If it weren't for the teeth on the gears, slight differences in circumference and other manufacturing inconsistencies would lead to an incorrect gear ratio inevitably. Since the majority of gears use teeth, those inconsistencies don't matter; the teeth make up the difference and provide for a lack of slippage. Pulleys, on the other hand, are frequently the same size and have a rubberized, or non-slip, outer covering. This combines with the autotensioner to keep the belt firmly seated around the pulley, rather than dangling down below the vehicle.
Gear ratio within a transmission is incredibly important. Gear ratio is what's responsible for your vehicle's acceleration and top speed. Both wide and close gear ratios have benefits that are inherent to that type, though most modern transmissions do a good job of running the middle ground between these two extremes.
The Incredible Uses of the Hydraulic Gear Pump
There are few technologies as widely accepted and implemented as hydraulics. You'll find hydraulic technology applied everywhere, but it is a dominant force in heavy machinery like backhoes and other heavy equipment, though it has applications within the automotive industry, as well. Hydraulic fluid provides enormous power, much more than a comparable electric motor.
External Hydraulic Pumps: The hydraulic gear pump has become an inexpensive, efficient fixture on hydraulic equipment. It provides a simple solution for providing the large amount of power needed for the lifting and digging that these large machines are designed for. An external hydraulic gear pump works on the principle that two spinning gears will propel the fluid from the reservoir, through the tubes and hoses to the hydraulic motors and engines, which will do the heavy work.
In the automotive industry, the hydraulic gear pump has a couple of applications. The first and most pervasive is in the oil pump with which almost all vehicles are equipped. It works through a pair of rotors, or gears, one set inside the other. The inner gear is offset from the outer, so that as the pair rotates, a gap forms. This gap creates a vacuum, which moves the oil through the pump and on to the engine, where it is needed.
Gear pumps are also used in automatic transmissions. The types of pumps used are very similar to oil pumps. They also operate on the same principle of positive displacement. Hydraulic gear pumps are used within automatic transmissions because of the benefits provided over a conventional electric motor and because they can be made to take up very little space. Many of these pumps can be put into a transmission to provide excellent fluid flow for the transmission, ensuring proper operation for a long life of hard use. The amount of fluid that is dispersed through the different channels and cavities of the transmission is controlled by the number, size and speed of the hydraulic gear pumps within the transmission.
The two gears within a hydraulic gear pump are what provide movement to the liquid in question. One gear is a simple idler gear, which does nothing but spin when turned. The other gear is called the driver, or drive gear. This is the gear that is responsible for turning both itself and the idler gear. The spinning creates vacuum and fluid is moved around the chamber in the gaps between the teeth of the two gears; no fluid moves between them. This is in contrast to the style of hydraulic gear pump used as an oil pump in automotive engines, when the oil moves between the two gears, but not around them.
The uses of the hydraulic gear pump are many and varied. It has become an integral element in almost every industry on the face of the earth; with this technology, you can literally move mountains or ensure that your vehicle continues moving for a long time to come. The hydraulic gear pump has made many things possible that would otherwise be all but impossible.
Worm Gears are a Common Type of Gear
The axes of worm gears shafts cross in space. The shafts of worm gears lie in parallel planes and may be skewed at any angle between zero and a right angle.
In worm gears, one gear has screw threads. Due to this, worm gears are quiet, vibration free and give a smooth output.
Worm gears and worm gear shafts are almost invariably at right angles
Advantages of Gear Technology
The advantages of gear technology over other transmission means are:
- Gear technology gives positive drives and constancy of speed ratio without any slippage
- In Gear technology, the drive is very compact due to short centre distances in such drives.
- Gear technology has high efficiency, service, and simple operation.
- Gear technology drives are capable of driving loads subjected to shock at speeds up to 20 m/s
- Maintenance of gear technology drives is inexpensive and if properly lubricated and operated, gear drives have the longest service life compared to other drives.
- Gear technology can be used where precise timing is desired.
- Gear technology can drive much heavier loads than other drives.
- Gear drives can be used for a wide range of transmitted power.
Gear Manufacturing -- From Broaching to Milling
Gear materials are usually made up of a composition of carbon and low alloy steel, including carburized steels. The application for which the gear is intended determines the choice of the material. To site an example, all gears made for food processing applications are made of stainless steel, or nickel-base alloys. The material is chosen for its corrosion resistant property. There are multiple ways that gear processing could be done, where gear blanks are put through different cutting and finishing process. These processes are:
- Broaching.
- Grinding.
- Honing.
- Hobbing.
- Lapping.
- Milling.
Broach is a type of metalwork, where the broach consists of a set of chisel points mounted on a single piece of steel, which progressively become taller. This tool is used for enlarging a circular hole into a shape that is not circular, such as, as square or any other shape. This tool is also used for cutting thin strip on the metal or a square keyway. This is done when manufacturing gears, driveshaft, pulleys, etc. The amount of material removed by the broach chisel depends on the material that is being cut. As an example, if the material happens to be steel, the broach tooth might remove 0.0025 inch, while the one designed to cut brass would remove as much as 0.004 inch.
Grinding
The grinding machine is typically used for finishing purposes or for making very light cuts, which is done by a rotating abrasive wheel. Typically these wheels come in various shapes and sizes, and made up of carious kinds of stones. In making the grinding wheel, stones of diamonds or organic materials are used. The wheel rotates at a speed that depends on the size of the grinder, and is power driven. The material is held in a bed-fixture, which guides and holds the work-piece. Either the grind wheel is made to move towards the work-piece or the work-piece moves towards the grinder.
Honing
The improvement of geometry in manufacturing of precision bores, the surface finish, and the dimensional properties of the work-piece are all done by the hone machine tool. The process so accomplished by the machine, is called honing. During the finishing process, the grind stone is held against the work-piece applying a force which differs from material to material.
Hobbing
This is a machine tool that is used for cutting gears. It is a milling machine that is used to form the gear blank as both rotate simultaneously at a fixed gearing ratio. The profile of the cutter is in the form of a helix, and this helps to generate curve on the sides of the teeth of the gear under process.
Lapping
It is a machine process, in which two surfaces are finished by rubbing with each other, with an abrasive in between the two. This is either done by hand or by a machine.
Milling Machine
To bring a complex shape on to metals and other solid materials, a milling machine is used. A rotating cutter or an endmill rotates on an axis held by a spindle, somewhat like a drilling machine, and a moving table, where the work-piece is held affixed by a jig, is moved towards the stationary rotating tool to accomplish the desired cutting action. In modern machines, this is done by the computer numerical control (CNC) machines.
Gear Cutting Is All About Hobbing, Shaping and Grinding
When machining a helical gear, or twist drill, on a machine that is operated manually, a true indexing fixture needs to be used. The indexing fixture would be required to be taken off from the drive worm, and fixed with a gear-train to the machine table, which can then be operated as a carriage on the lathe. With this kind of a system set up, while the machine table moves on the x-axis, the fixture would be moving at a fixed accurate incremental ratio with respect to the table. The machine table would move in a highly controlled manner via the index plate, producing a precision linear movement, such as, a vernier scale.
The gear-cutting tool comprises of a cutter body member, which has a circular shape, a front and a back surface, and an axis on which it rotates. An outer section of this cutter body has several individual projections, arranged equally spaced from each other around the cutter body. The spaces between the projections are so arranged that they can receive the slots for the cutting blades.
There are several machines which are used in gear cutting, and these are briefly mentioned below:
Hobbing Machine
This is a special kind of milling machine, which is used for cutting gears. It is the major machine with is essentially used for spur gears of involute form. This process uses the method of rotating the gear blank and the cutter at the same time, maintaining a fixed ratio between the cutter and the gear blank.
Gear Shaper
For cutting the internal and external gear teeth, a gear shaper machine tool is used. The name "shaper "comes from the action of the machine itself, where the concerned part is engaged on the forward stroke of the cutter, and pulls away from the part on the return stroke. The cutting tool of the shaper has the same pitch that of the gear to be cut.
Gear Grinder
This tool is used to automatically grind a helical gear. A drive source in this machine tool drives a rotating grinding wheel. A second rotating driving source is used to rotate a helical gear, meshed with the teeth on the grinding wheel. The third driving source in the machine tool displaces the helical gear and the second drive source simultaneously. Two pulse generators are used, which are connected to the first and the third drive sources. The pulse output from one is subtracted from the output of the other, and this differential is applied as the drive pulses for the second rotational drive.
Gear Reduction Is the Major Application of Gear Coupling
Gears are seldom used as a single entity. Almost all machines have gears working in pairs. Gear coupling has the following advantages:
Gear Reduction
Gear reduction is the major application of Gear coupling. The motor, which supplies the power to the system usually, has high power but lacks the essential torque required for work. In order to increase its torque the motor is connected directly to a small gear that is coupled with a larger gear. This results in an increase in torque at the expense of speed. Gear reduction is used in cars to convert the power of the motor into higher torque for motion of the wheels along the surface of the road.
Change in Direction of Movement
Most often the direction of application of torque is different than the direction of movement of the supply. The change in direction can be brought about by using gear coupling consisting of a system of two or more bevel gears. An example is the gear differential used in vehicles.
Change in Axis of Motion
When the rotary motion is to be changed to a different axis, gear coupling is used. Two or more gears are coupled in the same plane to change the axis of rotation. Either spur or helical gears can be used for this purpose. Helical gears are preferred as they work more silently in comparison to spur gears. An example is a windmill where the blades and motor are on different axis of rotation.
Change of Rotary to Linear Motion
Industrial machines like conveyor belts require conversion of the rotary motion of the motor to vertical motion for the movement of material. This is brought about by using gear coupling of a rack and pinion gear. The motor is connected to a small pinion gear which moves the rack gear for linear motion. This type of gear coupling is also using in crushers and water pumps.
Fixed Gear Bicycle
The first question that comes to your mind is what a fixed gear is. This term usually applied to bicycles, which have only one gear. This means that there is only one chain-ring fitted to the cranks, and at the back it has only one sprocket. These two are kept tensioned by a single loop of chain. There is no free-wheel mechanism, and this means that you cannot stop pedaling while the bike is in motion. The forward motion of the bike makes the pedals rotate independently.
Fixed gear provides only one gear ratio. This type of gear is mainly found in bicycles, which is also called a fixed-wheel bicycle, where the free-wheel is not present and runs on only one gear ratio. Fixed gear bicycles cannot coast owing the reason that there is no fixed-wheel mechanism, with the result that the pedals run in the same direction as that of the rear wheel. The rider of the bicycle can only restrict the pedal movement in order to stop the bike without having to apply the brake.
Generally, fixed gear bicycles have one gear ratio. Some are fitted with sprockets on each side of the hub, which provide the use of two gear ratios. There could be fixed gear on each side of the hub, or a fixed gear on one side with a free-wheel gear on the other. In case of a 42 teeth chain-ring there could be 19 teeth on the sprocket on one side, with the other having 17. This makes the gear in the later about 11% to 12% higher than the former.
There are distinct advantages of a fixed gear bicycle. In this type of a bike, either side of the drive drain has one cog each, there are no bearings or pawls in the free-wheel, and there is no deraillurs chain to apply the tension. This brings down the weight of the bike to quite an extent, which provides ease of riding and requiring less force to move forward. The drive system of the bike is direct, owing to the absence of the deraillurs, which would mean that, it provides you with increased pedaling efficiency. Your legs feel the traction between the rear tyre and the road. This makes the bike much ore safe to ride in snow and ice. This is the other great advantage in a fixed gear bike.
In normal bikes, the force on the pedals creates a linear motion to the bike. The pedal in this kind of a bike is connected to the chain-ring, which is the front sprocket. It is connected by cams, which translates the force on the pedals to a torque, and this rotates the chain. Where-as, in a fixed gear bicycle the pedals are directly connected to the rear wheel, and the force that is applied to the pedals makes the rear wheel to rotate. Under the circumstances, a fixed gear bicycle can be ridden backwards too. In this situation, the rider can apply the brake or slow down the bike only by restricting pedal movement.
The Most Commonly Seen Examples of Gears -- Bicycle Gears
Bicycles are machines that mostly attract the interest of the kids. It is a machine which lets you travel faster to destinations using the minimum of energy, compared to the energy that you would spend by walking or running to reach the place that you would want to go to. The mechanics that drive the bicycle are all open and exposed, and none of the machineries used are covered with sheet metal. Many of the kids, having curiosity in mechanical tendencies, cannot help but take their bike apart and put it back again.
You might have seen bicycles ridden in the movies or in a circus, where the front and the rear wheels of the bicycle have a funny "penny-farthing" shape. The bicycle used usually had a huge front wheel and a tiny wheel at the back. This type of bicycle appeared in the year 1870, but by the end of the century the bicycle was replaced by what we see normally these days. Just as we find in a kid's tri-cycle, the front wheel of the penny-farthing bicycle is directly connected. This would mean that as you pedal once, the wheel goes through one revolution. If the front wheel of the tri-cycle is taken as 16 inches, the circumference of the wheel comes to 50 inches. Therefore, with each revolution of the pedal, the front wheel travels through 50 inches. Pedaling at the rate of 60 rpm, the tri-cycle would be moving 50 inches per second, which comes to about 2.8 mph. If the pedaling goes up to 120 rpm, which is very unlikely, the tri-cycle would be moving at 5 mph.
The concept of gears in bicycles came from the fact that, it provides the rider with the facility to move faster without pedaling rapidly. If you take an example of a normal bike, the wheels are 26 inches in diameter. With the front chain wheel having 22 teeth and the rear having 30, a bike would have the lowest gear ratio. This would give a gear ratio of 0.73:1, meaning that with each pedal revolution, the front wheel would turn 0.73 times. This would make the bike move forward 60 inches with each pedal stroke. This comes to about 3.4 mph with 60 rpm of pedal revolution.
In the same way, the highest gear ratio in a bike is achieved with the front wheel chain having 44 teeth, and the rear wheel having 11 teeth, which provides a gear ratio of 4:1. Therefore, with 26 inches diameter of the front wheel, the bicycle moves forward by 326 inches with each pedal revolution. If the pedaling is done at 60 rpm, the bike would move forward at a speed of 18.5 mph. If the pedal speed can be doubled to the maximum of 120 rpm, the maximum speed of 37 mph could be attained. The speed range from 3.4 mph to 37 mph is an attractive feature, and that is the reason why bicycles have gears.
The gears at the front of the bicycle are known as chain wheels. This, what is called freewheel, is attached to the rear wheel. Depending upon what kind of a bicycle you have, the freewheel has 5 to 9 gears on it. There is only one direction that the freewheel can spin, and it is locked in the other. This way you can either pedal or you cannot.
There are two derailleurs at the front and back of a bicycle. These are used for changing the gears. The two small cogs at the rear derailleur spin freely. The tension of the chain is maintained by the arm and the lower cog of the derailleur. A spring holds back the cog and the arm. By shifting the gear, you are simply putting the chain on a different ring. Changing the left shifter, the ring at the pedal changes. There are three rings, where the smallest one is 1, the middle one is 2, and the third one is 3. By shifting down, you are changing to the smaller ring. To change the rings on the rear wheel, you use the right shifter, where the biggest ring is 1, and the largest is 6. There are markers in both the right and the left shift, and you can sift any of the shifters looking at the numbers.
Inside a Bevel Gearbox
Gears are used for changing the direction of rotary motion or to increase the torque. Industrial machines typically use a bevel gearbox for these purposes. Let us see the inner construction of a simple bevel gearbox and understand its mechanism.
A Peep Inside a Bevel Gearbox
On opening the housing of a bevel gearbox one comes to know that the construction is really simple. It consists of an input gear coupled with another gear called the output gear at right angles to each other. The gears can be either of spur or helical type. Helical gears are preferred as they are less noisy due to gradual engagement and have a longer life.
In case a reduction in speed is required, the diameter of the output gear is kept larger than that of the pinion. If only change in direction is required the diameters of both the gears are equal.
Materials commonly used are plastic or metal and depend on the load. Three gears are used in case the axis of rotation the same as that of input. The point of contact is well lubricated with gear oil.
Mechanism of a Bevel Gearbox
The electric motor or engine causes the input gear to spin which in turn rotates the output gear. Thus the rotary motion is passed on from the input arm to the output arm.
In case the diameter the output gear is larger than that of the input gear, the torque of the system increases at the expense of speed. Such a system is known as a reducer. The gears are at right angles to each other and hence the direction of the rotary motion is changed.
Applications of a Bevel Gearbox
The property of change of axis and speed of the bevel gearbox is used in a variety of industrial and automotive machines. It is used in turbines, pumps, grinders, etc. In vehicles the gearbox is used in the limited slip differential. One can clearly understand the working of the bevel gearbox by opening a simple hand drill.
Construction and Working of a Bevel Gear Reducer
One of the major applications of gears is gear reduction. The high power and low torque of the supply can be converted into high torque by coupling of a smaller input gear with a larger gear. There are different types of gear reducers depending on the types of gears coupled viz. worm gear reducer, spur gear reducer, bevel gear reducer etc.
Construction of a Bevel Gear Reducer
A bevel gear reducer consists of a small gear acting as a pinion coupled with another gear of a larger diameter at right angles to each other. The gears can be either of spur or helical type. Helical gears are preferred as they are less noisy due to gradual engagement. The material can be either plastic or metal depending on the application. Three gears can be used in case we need to keep the axis of rotation the same as that of input. The whole arrangement is sealed in a metal or plastic casing known as housing. The point of contact is lubricated with gear oil.
Working of a Bevel Gear Reducer
The diameter of the output being larger than that of the input gear, the torque of the system is increased at the expense of speed. Since the speed is decreased, this system is known as a reducer. The gears are at right angles to each other and hence the direction of the rotary motion is changed.
Advantages of a Bevel Gear Reducer
The efficiency of a bevel gear reducer is higher than that of a typical worm gear reducer. The bevel gears have high load capacity.
Applications of a Bevel Gear Reducer
Due to change in direction of the rotary motion the bevel gear reducer finds a variety of applications in industry and automotives. In industries it is used in turbines, pumps, cranks, etc. In automotives it is used in ordinary as well as limited slip differentials.
Architecture
The Department of Architecture, established in 1865, is the oldest architecture department in the United States and is consistently ranked as one of the top programs in the U.S. Read more about Architecture at MIT.
Materials Science and Engineering
Combustion synthesis of fullerenes and fullerenic nanostructures. Courtesy Vander Sande Lab.
Students, professors, and researchers in the Department of Materials Science and Engineering explore the relationships between structure and properties in all classes of materials including metals, ceramics, electronic materials, and biomaterials. Read more about Materials Science and Engineering at MIT.
Course 2-A: Customized Curriculum
To borrow the tagline from a famous computer maker's advertising campaign, some of our undergraduate students "think different". In fact, many of them do, and for them MechE offers Course 2-A: SB in Engineering as recommended by the Department of Mechanical Engineering.
This accredited program allows students with unique interests to create their own course of study by supplementing core requirements with 60 units of concentration subjects chosen either to connect MechE with another discipline or to develop a deeper focus in a particular area of MechE. Approximately one-fourth of the MechE student body - some 100 students - are currently enrolled in Course 2-A, and interest in the offering has been growing steadily.
According to Professor John H. Lienhard, MechE's undergraduate officer, "Course 2-A addresses the fast-growing trends in research and technologies at the interface of mechanical engineering and other disciplines such as biomedicine, nanotechnology, electromechanical systems, and neuroscience." Flexibility is the key element - providing undergraduates with the ability to customize a curriculum around their specific research interests - yet MechE helps to facilitate the elective selection process by recommending a variety of tracks that mirror several important areas within MechE. While students are not limited to these tracks, they are designed to help students focus their area of special interest. The tracks include:
- Biomedical Engineering
- Energy Conversion Engineering
- Engineering Management
- Nano/Micro Engineering
- Sustainable Development
- Precision Engineering
- Product Development
- Control, Instrumentation, and Robotics
- Mechanics
Frontiers of learning
"A program like 2-A allows for a curriculum that evolves as technology evolves," says Lienhard. "It takes a complex skills set to solve the complex problems of today. 
For some students, Course 2-A is a strong preparation for graduate study in a focused area. For others, it's an entrée to a professional program, such as medicine, law, or an MBA."
Frequently, and unsurprisingly, some students come up with a curriculum plan that focuses on disciplines for which no formal structure exists, such as building technology, computational engineering, or environmentally sustainable engineering. In such cases, MechE faculty advisors are always available to help students structure their program. Regardless of the form, format, and focus of their studies, each program must include a capstone subject that brings it all together in the application of solving a real-world design problem.
The best way, of course, to understand the reasons and rewards of choosing Course 2-A is to hear it from the mouths and minds of the students themselves.
Laura Martini '08
"I'm doing Course 2-A with a focus in Product Design. My course of study will include classes from the architecture school, aero/astro, computer science, electrical engineering, architecture, higher-level MechE classes, and maybe management. I like 2-A because it allows me to have a greater breadth of knowledge. I don't aspire to be the type of engineer who builds bridges or skyscrapers, so I don't feel that it's necessary for me to take the entire MechE core curriculum. 
I also have very eclectic interests, so I like the fact that 2-A allows me the flexibility to take classes from a wide range of disciplines, while still giving me a solid mechanical engineering foundation.
"Another reason why I chose to pursue product design via MechE rather than another course like architecture is because I like the systematic way that the course teaches you to approach problem-solving. I'm also very hands-on, and I like that you get to go beyond the theoretical level in mechanical engineering."
Michal Ruchelsman '07
"I elected to major in 2-A with a focus on Premed/Biomedical Engineering. I've always had an appreciation for engineering and been interested in biological systems and medicine, particularly the areas of biomechanics, orthopedics, and implant design. I've considered pursuing an M.D., an M.S./Ph.D. in engineering, or even a combination of the two. I knew, therefore, that I wanted to graduate with a strong engineering background but also not limit myself to a specific engineering discipline. The 2-A program seemed like the logical choice. It would equip me with a strong mechanical engineering background, yet also allow me the schedule flexibility necessary to take the classes I'd need to matriculate into medical school.
"In addition to Course 2 classes, my curriculum includes 20.310 [Molecular, Cellular, and Tissue Biomechanics], 20.110 [Statistical Thermodynamics of Biomolecular Systems], 3.051 [Materials for Biomedical Applications], 7.05 [Biochemistry], 7.02 [Experimental Biology], 5.12/5.13 [Organic Chemistry I & II], and 5.310 [Laboratory Chemistry]. I hope to also take two graduate classes as a senior: 20.441 [Biomaterials-Tissue Interactions] and 20.451 [Design of Medical Devices and Implants]."
Center for Ocean Engineering: Anchors Away
Originally established in 1893 as the Department of Naval Architecture and Marine Engineering (NA&ME), and rechristened the Department of Ocean Engineering in 1970, the program officially merged with Mechanical Engineering on January 1, 2005. Thus also emerged the Center for Ocean Engineering (COE).
The COE is more than just a new name for a hoary program. According to Professor Michael Triantafyllou, director of the COE, "The COE represents a new, more focused effort to preserve and expand the research and educational efforts in Ocean Engineering. At the same time, it builds on the program's origins."
When the original NA&ME department was created, Boston was a major sailing center and the US Navy was in critical need of technical expertise. "We were obviously well-positioned to capitalize on this situation," says Triantafyllou, "and a collaboration was initiated between MIT and the Navy that exists to the present day. In fact, half of all technical admirals in the US Navy today are graduates of MIT's ocean engineering program."
Another key partner of COE is the Woods Hole Oceanographic Institution (WHOI), the world's largest private institution dedicated to research and higher education at the frontiers of ocean science. MIT and WHOI have been offering a joint degree program in both oceanography and oceanographic engineering for nearly 40 years. Students typically spend at least the first two years at MIT, with summers at WHOI.
Seven seas, four foci
As currently structured, the ocean engineering program at MIT focuses on four areas: acoustics, hydrodynamics, structures and structural dynamics, and design and marine robotics.
Acoustics - Electromagnetic waves can't travel far underwater, so vision and navigation must be accomplished acoustically, the same way that some marine mammals communicate and locate prey. MIT's ocean acoustics group is one of the leading centers of sonar research in the world, and the sonar systems developed for the US Navy are capable of extremely complex signal processing.
Hydrodynamics - Water is an unusual medium, a random, turbulent environment with different properties at the surface and below, affecting how ships, humans, and animals, as well as the atmosphere interact with it. Understanding hydrodynamic phenomena, therefore, is critical in ensuring seaworthy ship design. "Recently," says Triantafyllou, "we have expanded our study to include 'internal waves,' which are waves supported on the pycnocline (a layer of the ocean where the water density changes rapidly with depth). These waves can put enormous forces on deep offshore structures."
Structures and Structural Dynamics - Ocean structures and vessels are complex systems; therefore, designing and fabricating more efficient and higher-performing structures (such as offshore platforms, supertankers, trans-oceanic cables, and deep submersibles) is a very challenging engineering task. 
Students study the structural mechanics of vessels, sources of stress, the behavior of a range of materials, and crashworthiness.
Design and Marine Robotics - Continuing ocean exploration requires robots that can go where humans cannot, such as waters that are very deep, shallow, or stormy. COE's marine robotic groups have developed some of the most advanced autonomous vehicles and smart sensors in use today. In addition, COE's biomimetic robotics group studies how different marine animals swim in order to develop robots that can propel themselves through the water like fish, emulating their outstanding performance. A current robotic project explores the swimming of sea turtles in order to develop stable platforms with outstanding maneuvering ability and large sensor payload.
Full steam ahead - With more than a century of innovation and knowledge behind it, the COE is looking ahead to the challenges and opportunities that lie ahead. According to Triantafyllou, "Though humans have sailed for thousands of years, we know less today about the ocean depths than we do about outer space. There is still much to learn on the effect of global warming and climate change in the oceans - the ocean, after all, is the major depository of carbon dioxide. The more we know about the ocean the better we will be able to predict and prevent tsunamis, preserve undersea life, and better utilize the more than 70% of the earth's surface covered by water.
Fuel from the fields
The charcoal project created a process for producing charcoal that uses bagasse - the fibers from sugar cane stalks that remain after the juice has been extracted - instead of wood. The goal was to create an alternative charcoal briquette with the same density as one made with wood, that burns more cleanly, and is less costly and environmentally damaging to produce. Pilot testing in Petite Anse, a small fishing village in northern Haiti, showed promising results using locally available skills and materials. Further research in El Salvador has refined the technique, and large-scale implementation is due to start in summer 2006.According to Amy, "The Charcoal Project is a good model of what we want to accomplish in D-Lab: solutions that are simple, cheap, and easy to produce and distribute; that deliver health, environmental, and economic benefits; and that serve an urgent need." In many ways, Amy is able to provide her students with the undergraduate experience she was looking for at MIT more than 20 years ago. In making her work relevant to her life, Amy is having an impact on many other lives around the world.
The ABC's of D-Lab
Currently, Amy teaches D-Lab, a series of courses and field experiences that gives students a grounding in the technical challenges that developing countries face - then gives them the opportunity to travel, find a need, conceive a solution, and then prototype and implement it. Target nations include Brazil, China, Ghana, Guatemala, Haiti, Honduras, India, Lesotho, and Zambia. Students travel during the January Independent Activities Period (IAP).
"We partner with diverse organizations, including universities, technology centers, foundations, and businesses," Amy says. "For example, one corporation sponsors our work in Brazil because it has operations there. In Zambia, we partner with the local chieftainess and the whole village gets involved."
Designing technologies for developing countries is particularly challenging because of the numerous constraints. A reliable electrical system, for example, is not a given. In addition, cost, durability, and ease of use are important. Students learn and apply fabrication and prototyping skills to help them assess the viability of their concepts.
Amy Smith: Service Engineering
Raised with the value of serving others, and partly inspired by a year she spent in India as a child, Amy decided to join the Peace Corps. It was while working in Botswana that she saw first hand that populations most in need of innovative technological solutions often lack the skills and resources to create them. Upon returning to MIT in the 1990s, she requested and received funding to travel to Africa to identify engineering projects. Her master's thesis was a mechanized, low-cost grain mill that not only worked better than previous methods, but also used less energy and cost less than a quarter of the price of existing mills.
Some of her other inventions include a laboratory incubator that doesn't require electricity and a low-cost chlorination system for community water supplies. It's not surprising that she is the co-founder of the MIT IDEAS Competition, which encourages teams to develop and implement projects that make a positive change in the world. Her ingenuity and commitment to serving the needs of the less fortunate have been well-recognized: in 2000, Amy became the first female winner of the Lemelson-MIT Student Prize for invention and in 2004, her work earned her a prestigious MacArthur Fellowship (the "genius grant").
Friday, December 18, 2009
Micro & Nano Engineering
Mission
The Micro and Nano Engineering area seeks to create new engineering knowledge and products on the micro and nano-scale. Our focused efforts include:
* Identifying and solving grand challenges in micro and nano technologies
* Providing design, fabrication, and enabling tools to other groups
* Educating students about micro and nano science and technologies
Overview
Micro- and nano-scale research can be categorized into three broad domains: theoretical foundation (science) research, applications research, and enabling tools research. Specific research areas within each domain include:
* Science - quantum computing, molecular modeling and simulation, mechanics and materials, chemistry
* Applications - microfluidics; bioengineering; optics, magnetics, and imaging; energy; thermal systems, carbon nanotube (CNT)
* Tools - design, micro electro-mechanical systems (MEMS), nanomanufacturing
In addition to multi-domain research, our strengths are that we are multidisciplinary, networking both inter- and intra-departmentally; and that we are multi-scale, with the ability to design and build systems at all size scales, and integrate micro/nano structures into multi-scale systems.
Our facilities include the Microsystems Technology Laboratories, which house three clean-room facilities (the Integrated Circuits Laboratory, Technology Research Laboratory, and Nano-structures Laboratory), as well as the Research Group Laboratories and the Computational and Communication Network Facility. In addition, the brand new Pappalardo Nanomanufacturing Facility (aka Pappalardo II) provides nearly 5,500 square feet of state-of-the-art space for nano-scale mechanical engineering research and education.
Design, Manufacturing, & Product Development
Mission
The Design, Manufacturing, and Product Development area seeks to educate a new generation of versatile innovators by integrating entrepreneurship, creativity, design, prototyping, manufacturing, and systems with new, leading-edge techniques and processes for Design, Manufacturing, and Product Development.
Overview
Design, Manufacturing, and Product Development is the complete set of activities needed to bring new devices, technologies, and services to the marketplace. These activities span the entire product life-cycle, from the identification of a market opportunity or need, through design, testing, manufacture and distribution, and end of useful life.
Design, Manufacturing, and Product Development is an integral part of the MechE program in that it satisfies two key criteria: it has a significant societal impact, and it offers significant intellectual challenges:
- Societal impact - Engineering's primary value to society is its ability to deliver products and solutions that improve quality of life. Their benefits may include enhanced safety, convenience, cost-effectiveness, usability, functionality, and marketability. They can help people live longer and/or happier lives, and generate the material wealth required to fund and fuel continued engineering improvements.
- Intellectual challenges - For products to be competitive technically, they must incorporate appropriate new technologies and be refined using leading-edge modeling, simulation, and experimental methods. For products to be competitive commercially, they must be innovative, elegantly designed, and cost-effective within any number of constraints. This requires creative problem-solving techniques that engage both sides of the brain.
Many MechE students apply Design, Manufacturing, and Product Development skills and techniques on extracurricular design work for organizations and student activities such as Design That Matters, Formula SAE, Satellite Engineering Team, and the Solar Car and Hovercraft clubs. Some projects are intended as flagship products for new companies and are entered in the $50K competition.
