Friday, November 29, 2019

Manufacturing Nanocomposite Materials

Manufacturing Nanocomposite Materials Manufacturing Nanocomposite Materials More payload. Lighter components. Stronger parts. Lower cost. Carbon nanotubes have long promised these and other highly desired properties. In spite of their well-known strength and stiffness, however, nanotubes have proven to be difficult to harness in manufacturing composite materialscombinations of very strong, stiff, reinforcing carbon fibers in an epoxy resin that acts like glue to hold them in place.But in recent years, mechanical engineers have been figuring out ways to incorporate nanotubes into resins, to increase the strength and durability of composite materials without forcing companies to reinvent their production processes. As a result, nanotubes are now progressing beyond such niche markets as high-performance sports equipment and into the bodies of boats, cars, and planes.It looks like conventional epoxy-impregnated carbon fiber cloth, but this prepreg from Nanoledge Inc. contains nanotubes t o boost mechanical properties.The ProblemThe carbon bonds, which link so tightly with one another to form nanotubes, also make the nanotubes inert. They do not dissolve in water, oils, or solvents. As a result, there is no way to disperse raw nanotubes in resins. Indeed, adding raw nanotubes to a resin can actually degrade a composites properties. Like strands of half-cooked spaghetti in water that is not stirred enough, undispersed nanotubes tangle up and form clumps. In resins, those clumps become places where stresses concentrate and initiate crackssimilar to what happens when a hammer strikes concrete and cracks form around the largest aggregates.Researchers have found ways to compatibilize nanotubes by attaching certain molecules to the nanotube surface the part of the molecule farthest from the nanotube contains a chemical group that disperses in the resin. As the resin flows, those molecules carry the lassoed nanotubes with them.Velozzis Supercar (top) will use nanotube-enhan ced composites for structural parts, but its less expensive Solo (bottom) will use them only in high-impact applications.Moreover, nanotubes long, thin shape and high surface area also make them jam up when the resin flows, like logs jamming in a flowing river. Adding barely 1 percent nanotubes by weight can transform epoxy having the viscosity of light motor oil into the consistency of peanut butter. Yet that is enough to make stronger and more durable composite materials. The resin is the vulnerable component of the compositethe part that is brittle and susceptible to cracking. Strong nanotubes help the resin transfer loads to the reinforcing fibers more efficiently. They also act like tiny dams to keep cracks from spreading. Nanotubes improve resistance to impact, fatigue, and microcracking, all properties related to the resins. Nanotubes added to a resin boosts composite flexural strength and modulus by 30 to 50 percent and tensile properties by 20 to 30 percent.Some formulators compatibilize nanotubes for infusion processes, which pump resin into reinforcing fiber preforms. For the most part, though, large parts are made from prepreg, thin layers of woven reinforcing fibers pre-impregnated with nanotube-containing epoxy. Because the layers are so thin, the nanotubes do not have to flow through large volumes of space. The layers are partly cured to solidify the resin. Workers lay tacky layers of prepreg on one another to build up a part, then put it under a vacuum, and heat it to cure the resin and form a solid component.Unlike most advanced materials, nanotubes provide advanced performance at lower cost. voreingestellt modulus carbon fibers cost about $10 to $12 per pound intermediate modulus fibers cost about five times higher $60 per pound. Adding just 1 percent nanotubes to the resin gives a standard composite the properties of a part made from prepreg made with intermediate modulus fibersbut costs 10 to 15 percent less.The Proof Is in the ProductIn la te October 2010, a prototype experimental unmanned surface vehiclethe naval equivalent of the unmanned aerial vehicles flown by the military in Afghanistan and elsewherebegan its first tests in Puget Sound, Washington. The 54-foot boat, called the Piranha, weighs only 9,000 pounds including engine, transmission, and deckyet can carry up to 15,000 pounds of fuel, surveillance equipment, and weapons. The secret? Less than 0.5 percent (by weight) of nanotubes in the prepreg for its hullwhich is the largest nanotube-reinforced structure ever built. Its builder, Three Points Composites just south Seattle, designed the Piranha to cruise more than 2,000 nautical miles at a clip of 25 knots and stay at sea for days without refueling, performance that could make it suitable for protecting ships against piracy.Nanotubes may improve the safety of lightweight cars. In the high-performance electric Supercar and its plug-in hybrid Solo by the Los Angeles designer Velozzi, fully 80 percent of thei r structure will be carbon composites, including the fahrgestell and body panels. Standard composites are brittle, however, splintering and shooting out fragments in a collision. Velozzi is incorporating nanotubes to make the cars both lighter and safer. Nanotubes allow the use of 30 percent less carbon fiber, making for a part that not only weighs less but also is less brittle, so it fails in a less catastrophic way, like tempered glass.And both Boeing and Lockheed Martin are exploring was of incorporating nanotubes into established production methods to improve performance of aircraft. Unmanned drones are a likely early aerospace applicationadding nanotubes to make the wings stiffer, to maintain the aircrafts efficiency even when carrying heavy payload.Adapted from Positive Reinforcement by Alan S. Brown, Associate Editor, Mechanical Engineering, March 2010.Unlike most advanced materials, nanotubes provide advanced performance at lower cost.

Sunday, November 24, 2019

A Conference for MBA Veterans

A Conference for MBA Veterans A Conference for MBA Veterans The potential employers of the corporate world show no hesitation in recruiting eligible veterans with a MBA degree, as they normally have excellent leadership skills. They also excel in motivating a team and have sound technical knowledge. The keynote speakers of this years darbietung are Alex Gorsky and Russ Laraway, former veterans themselves. They serve as senior level executives now. The event has attracted 24 world-class companies in just three years of its commencement. Google and Johnson and Johnson are the key sponsors of the 2011 MBA Veterans Career Conference.More than 200 veterans with MBA degrees from various prestigious institutions like MIT and UCLA are expected to attend the conference this year. 66% of last years participants reported getting at least one eligible interview call from this event. The number is expected to rise this year. Watch the Live webcast of the 2011 MBA Veterans Career Conference from 8am CST to 1pm CST on Friday, October 28th at mbaveterans.com.

Thursday, November 21, 2019

Jobs That Put Your Taxes to Work

Jobs That Put Your Taxes to WorkJobs That Put Your Taxes to WorkJobs That Put Your Taxes to WorkYour taxes make good things happen.Nobody likes dealing with their taxes. It seems that every time you look at your finances, more and more money is going to taxes. Sales tax, property tax, and state and federal income taxes are the biggest culprits. The worst part? That money leaves and you never see it again. What does it ever do for you?Believe it or leid a lot, and right in your hometown.There are many people out there every day working to make your life better whose jobs are paid for, or at least made possible by, your tax dollars. They keep you safe, help you get around, and even work diligently for your childrens future. Its extremely difficult to determine exactly how each of your tax dollars goes to any one job the system is complex. But we leise know what jobs that your taxes bring to life. Here are seven jobs that your taxes help pay for that are making your life better each d ay.1. PoliceIf you think people are inherently good, you get rid of the police for 24 hours see what happens. Sylvester StallonePolice patrol your streets and highways, hoping to keep everyone safe. Its a tougher job in some cities than in others, but make no mistake, theyre putting their lives on the line every day. From protecting your home to helping you when your car stalls out at an intersection, police provide services that are crucial to your neighborhood.Tax dollars from local property and sales taxes help to pay those wages. Federal and state income tax dollars are used to help recruit and train officers and provide them with the equipment they need to do their job effectively.2. Public School TeachersIn a completely rational society, the best of us would be teachers and the rest of us would have to settle for something else. Lee IacoccaTeachers spend hours with our nations children every day. They shape their learning from first reading lessons to complex trigonometry a nd physics. Yet, they make less than most other professionals, and pay increases lag behind the pack.Public schools derive much of their funding from local tax dollars as well as federal programs that are created to help them continue to educate our youth without tuition costs to parents. Property taxes play a big role in keeping public schools afloat, but as much as 2% of the total federal tax budget is directed to education as well.3. FirefightersOne thing thats great about firefighters If they dont have the equipment they desperately need, they dont have the help, they dont care. Theyll do it on their own. Denis LearyIs there anything more horrifying than the thought of your home going up in flames with your possessions, your memories, and your loved ones inside? When the unthinkable happens, firefighters jump into action. They put their own lives at risk to protect the things that mean the most to you. Each year, a number of these brave public servants lose their lives as they try to save others.Its your tax dollars that help them do just that. From funding for equipment to salaries for professional firefighters, its a no-brainer that local, state, and federal tax dollars are well spent on their services.4. Public Library WorkersFor those without money, the road to that treasure house of the imagination begins at the public library. Pete HamillUnderutilized, underappreciated, and underfunded Thats the story of todays public libraries. From great books to online resources and electronic media, public libraries offer a wealth of information and assistance to anyone who needs it. Librarians and staff at your local public library are largely paid by public funds gained through taxes and levies. If you havent checked out the library in awhile, you may be surprised at how many great services they offer to the public. Far from being a dinosaur, public libraries now have more to offer than ever before. If you dont like the idea of your hard-earned money helping to pay for the people who keep it up and running, stop by and see for yourself just how many people benefit from a good public library.5. Public OfficialsWhen the burdens of the presidency seem unusually heavy, I always remind myself it could be worse. I could be a mayor. Lyndon B. JohnsonFrom your local mayor to judges to your state congress, your tax money is used to pay their wages. The amount of money each one makes can vary greatly depending on where they are. Even the 50 state governors earn varying amounts, and its probably less than youd expect. Like it or not, the people we elect to run our towns, states, and country deserve to be paid for their time and efforts, and your tax dollars are the pool from which they draw.6. Road MaintenanceIn New York, there are so many potholes, theyre like craters on the moon. Thats another traffic thing. Jimmy FallonYou know that pothole in your neighborhood? You know the one. Its the one that makes you spill coffee on yourself at least on ce a week as you swerve to avoid it. Well, quit swerving and do something about it. While the crews that work on streets may be private companies, the contracts they work on stem from local and state tax money. You have a right to call in and get that pothole fixed before they owe you a new blazer without coffee stains.The same goes for sidewalks and bike trails. If you walk, run, bike, or drive on it, chances are your tax dollars are paying to maintain it.7. Public Defense AttorneysMost criminal defendants do not get adequate representation because there are not enough public defenders to represent them. There is a lot that is wrong. John GrishamYou hear it all the time on those television cop shows If you cannot afford an attorney, one will be appointed for you. You didnt think these guardians of the unfortunate were working pro bono, did you? Public defenders get paid a salary that is comparable to other attorneys in the same area with similar experience, but instead of being pa id directly by a client, they are paid using public funding. It can be an expensive, but important part of your tax dollars work.As you sign your income tax papers, add a few dollars for sales tax, or wince at the number on your property tax bill, it may help to know that your money is not going into thin air. Most of these jobs are funded by a mixture of those three kinds of taxes and the funds and grants that come from them. If you want nice streets, dependable law enforcement and firefighters, and even a good public school for your kids, its your tax money that makes it possible. No one wants to pay more taxes than necessary, but to keep your community running the way you expect it to, your dollars have to go to work. Of course, that doesnt mean you should feel guilty if you get a refund. Enjoy itInterested in one of these careers? Submit for a free resume review to find out how your resume stacks upRecommended ReadingHow to Include Your Job Search on Your Tax ReturnExecutive Res ume Makeovers for the ObamasHow to Write a Federal Resume