BY LOUIS BERGERON AND STEPHANIE KENITZER

Wind farms can be built in mountainous regions, such as in Spain (above), or placed offshore like the one at Middelgrunden (other photo), near Copenhagen, Denmark.

LM Glasfiber

Wind farms can be built in mountainous regions, such as in Spain (other photo), or placed offshore like the one at Middelgrunden, near Copenhagen, Denmark.

Wind power, long considered to be as fickle as wind itself, can be groomed to become a steady, dependable source of electricity and delivered at a lower cost than at present, according to scientists at Stanford University.

The key is connecting wind farms throughout a given geographic area with transmission lines, thus combining the electric outputs of the farms into one powerful energy source. The findings are published in the November issue of the American Meteorological Society’s Journal of Applied Meteorology and Climatology.

Wind is the world’s fastest growing electric energy source, according to the study’s authors, Cristina Archer and Mark Jacobson, who will present their findings Dec. 13 at the annual meeting of the American Geophysical Union in San Francisco. Their talk is titled “Supplying Reliable Electricity and Reducing Transmission Requirements by Interconnecting Wind Farms.”

However, because wind is intermittent, it is not used to supply baseload electric power today. Baseload power is the amount of steady and reliable electric power that is constantly being produced, typically by power plants, regardless of electricity demand. But interconnecting wind farms with a transmission grid reduces the power swings caused by wind variability and makes a significant portion of it just as consistent a power source as a coal power plant.

“This study implies that, if interconnected wind is used on a large scale, a third or more of its energy can be used for reliable electric power, and the remaining intermittent portion can be used for transportation, allowing wind to solve energy, climate and air pollution problems simultaneously,” said Archer, the study’s lead author and a consulting assistant professor in Stanford’s Department of Civil and Environmental Engineering and research associate in the Department of Global Ecology at the Carnegie Institution.

It’s a bit like having a bunch of hamsters generating your power, each in a separate cage with a treadmill. At any given time, some hamsters will be sleeping or eating and some will be running on their treadmill. If you have only one hamster, the treadmill is either turning or it isn’t, so the power’s either on or off. With two hamsters, the odds are better that one will be on a treadmill at any given point in time, and your chances of running, say, your blender, go up. Get enough hamsters together, and the odds are pretty good that at least a few will always be on the treadmill, cranking out the kilowatts.

The combined output of all the hamsters will vary, depending on how many are on treadmills at any one time, but there will be a certain level of power that is always being generated, even as different hamsters hop on or off their individual treadmills. That’s the reliable baseload power.

The connected wind farms would operate the same way.

“The idea is that, while wind speed could be calm at a given location, it could be gusty at others. By linking these locations together we can smooth out the differences and substantially improve the overall performance,” Archer said.

As one might expect, not all locations make sense for wind farms. Only locations with strong winds are economically competitive. In their study, Archer and Jacobson, a professor of civil and environmental engineering at Stanford, evaluated 19 sites in the Midwestern United States with annual average wind speeds greater than 6.9 meters per second at a height of 80 meters above ground, the hub height of modern wind turbines. Modern turbines are 80 to 100 meters high, approximately the height of a 30-story building, and their blades are 70 meters long or more.

The researchers used hourly wind data, collected and quality-controlled by the National Weather Service, for the entire year of 2000 from the 19 sites. They found that an average of 33 percent and a maximum of 47 percent of yearly-averaged wind power from interconnected farms can be used as reliable baseload electric power. These percentages would hold true for any array of 10 or more wind farms, provided it met the minimum wind speed and turbine height criteria used in the study.

Another benefit of connecting multiple wind farms is reducing the total distance that all the power has to travel from the multiple points of origin to the destination point. Interconnecting multiple wind farms to a common point and then connecting that point to a far-away city reduces the cost of transmission.

It’s the same as having lots of streams and creeks join together to form a river that flows out to sea, rather than having each creek flow all the way to the coast by carving out its own little channel.

Another type of cost saving also results when the power combines to flow in a single transmission line. Explains Archer: Suppose a power company wanted to bring power from several independent farms—each with a maximum capacity of, say, 1,500 kilowatts (kW)—from the Midwest to California. Each farm would need a short transmission line of 1,500 kW brought to a common point in the Midwest. Then a larger transmission line would be needed between the common point and California—typically with a total capacity of 1,500 kW multiplied by the number of independent farms connected.

However, with geographically dispersed farms, it is unlikely that they would simultaneously be experiencing strong enough winds to each produce their 1,500 kW maximum output at the same time. Thus, the capacity of the long-distance transmission line could be reduced significantly with only a small loss in overall delivered power.

“Due to the high cost of long-distance transmission, a 20 percent reduction in transmission capacity with little delivered-power loss would notably reduce the cost of wind energy,” added Archer, who calculated the decrease in delivered power to be only about 1.6 percent.

With only one farm, a 20 percent reduction in long-distance transmission capacity would decrease delivered power by 9.8 percent—not a 20 percent reduction, because the farm is not producing its maximum possible output all the time.

Archer said that if the United States and other countries each started to organize the siting and interconnection of new wind farms based on a master plan, the power supply could be smoothed out and transmission requirements could be reduced, decreasing the cost of wind energy. This could result in the large-scale market penetration of wind energy—already the most inexpensive clean renewable electric power source—which could contribute significantly to an eventual solution to global warming, as well as reducing deaths from urban air pollution.

A wind power feasibility study of potential sites along the California coast by Mike Dvorak, a Stanford doctoral student in civil and environmental engineering who is working with Jacobson and Archer, also is being presented during an afternoon poster session at the meeting.

Associate Professor Giri Venkataramanan (center) and a team of workers built a wind turbine in the Scottish Highlands. The community there is not connected to the electrical grid. (Large image)

The rolling hills of the Scottish highlands are dotted with small stone houses. Their residents, mostly farmers and craftsmen, enjoy a peaceful existence miles from the nearest city—so far, in fact, that they are not connected to the nearest power grid.

That is where Electrical and Computer Engineering Associate Professor Giri Venkataramananbegan his sabbatical. He did not travel to Scotland to enjoy its peace and tranquility, but rather as part of a team building an electricity-generating wind turbine. Without connection to energy utilities—power lines cost between $50,000 and $1 million per mile, says Venkataramanan—the region’s inhabitants must generate their own power.

Wind turbines, machines that use the energy from the wind to turn a generator, are common in the area. “Every house has one or two turbines. They also use solar panels and have batteries to store charge for when there’s no wind or sun,” says Venkataramanan. “They live pretty comfortably.”

The team had no prior turbine-building experience, but came prepared to saw, drill and weld. It took the team one week to build the turbine, by hand, from the raw materials. Turbines the size of this one generally average 200 watts at a reasonably windy site. At this rate, one turbine can generate enough electricity in a day to power the modest needs of a small home, says Venkataramanan.

“That was a very eye-opening experience for me. Even in that primitive setting, we were able to accomplish something. I was quite impressed,” says Venkataramanan. “I thought, we ought to do something like that on campus.”

Inspired by that thought, he spent the rest of his sabbatical learning how to implement a program about this clean, sustainable solution for rural energy on a university campus.

A few months after returning from Scotland, Venkataramanan traveled to the Tokyo Institute of Technology to lecture about his research activities. While he was there, he investigated a new undergraduate program in international development engineering, which focuses on sustainable global development.

Venkataramanan then spent three months as a visiting research associate at the University of California-Berkeley. While conducting research and writing a paper on rural electrification for the Journal of Energy Engineering, he also assembled a team of students to build a wind turbine like the one he built in Scotland. Although without a full-scale workshop or credit, the students worked weekends to assemble the turbine in a team member’s garage.

The students’ enthusiasm for the project did not wane after Venkataramanan’s departure, and the workgroup continues to meet. “Since I left Berkeley, they’ve developed more wind-focused activities and are planning to install two or three more wind turbines,” he says.

While at UC-Berkeley, Venkataramanan also visited other schools and institutions focused on sustainable energy development. The efforts he witnessed inspired him, such as the University of Colorado-Denver student team that not only built a wind turbine, but also installed it in a tribal community in India.

For the spring of 2006, Venkataramanan received a fellowship as a visiting researcher at the Federal University of Minas Gerais (UFMG) in Belo Horizonte, Brazil. “The first thing I did in Brazil was get a bunch of students together to build a wind turbine,” he says. Despite bureaucratic red tape, the team found the parts it needed and finished the turbine.

To finish his sabbatical, Venkataramanan spent the summer as a visiting scientist at Gazi University in Ankara, Turkey, where he also recruited a team of students to build another wind turbine, bringing his number of construction endeavors to four. With these experiences fresh in his mind, he returned to UW-Madison in fall armed with ideas for ways Wisconsin students could help develop rural energy.

Venkataramanan is planning several courses that will give students opportunities to learn about and work with energy technology. This spring, he piloted a section of Introduction to Engineering (InterEgr 160) that focuses on small-scale wind turbines, intending to integrate it into the curriculum long-term. He also has integrated renewable energy technologies and developing electric grids into his ECE 714 course, Utility Applications of Power Electronics, focusing on under- developed and off-grid communities.

Venkataramanan (right) helped a team of students in Brazil build a smaller scale wind turbine like the one he built in Scotland. He also built turbines with student groups in Turkey and California. (Large image)

To give students hands-on experience, Venkataramanan is planning a section of the service-learning program Engineering Projects in Community Service that will enable them to build and install a renewable energy system, such as wind turbines, in an off-grid community.

Venkataramanan believes that adding rural, renewable energy development to an engineering curriculum could make a difference not only for the students involved and the communities they reach, but also on a global level. “There are two billion people without electricity access in the world. That’s one-third of the population. Many of these communities don’t have economic wealth for people to go and build power lines. By engaging our students in projects like this, they can learn to think globally and perhaps come up with creative solutions for the future,” he says. “The potential for what our students and faculty can do is unlimited; we just have to be creative.”

by Hilary Parker

As junior Nick Frey sat in his fluid mechanics course last spring, he was thinking about bicycles — but he wasn’t daydreaming.

Rather, the mechanical and aerospace engineering major was conjuring ways to put his newfound knowledge to work in modifications to his racing bike. The reigning national time-trial champion and co-president of the University cycling team, Frey has aerodynamic aspirations that go far beyond taping the vents on his helmet — a common practice among racing cyclists to reduce wind resistance.

The day before heading to the world championships in Germany this fall, Princeton junior Nick Frey put himself through a grueling test to simulate the upcoming race route. He records distance, speed, cadence and power output during workouts like these in the Dillon Gymnasium bike room to determine his best racing strategy. Photo by Denise Applewhite“Nick was one of the most active students in my class — always wanting to know more details, or to make sure he understood everything,” said Alexander Smits, the chair of mechanical and aerospace engineering and Frey’s fluid mechanics professor. “It was great to have him in the class. He bemoaned the fact that Barrie Royce and I were no longer offering our freshman course, ‘The Bicycle and the Engineer,’ but he seems to have put his fluid dynamics know-how to very good use.”

A prime example is the modification Frey made to house the brake cables on his time-trial bike. When he learned that solid cylinders have high air resistance, Frey equated cylinders with bicycle brake cables — and saw an opportunity to go faster.

He knew that once an object, such as a cyclist, is moving fast enough, the main barrier to going even faster is wind resistance; nearly all the cyclist’s strength goes into pushing aside air. Conversely, reducing that resistance by a relatively small amount can result in major increases in speed with minimal increased effort. So Frey enclosed his brake cables in a special housing shaped like an airplane wing that shields them from the wind, reducing the resistance on his bike while still meeting the requirements of the organization that oversees competitive cycling events throughout the world, the Union Cycliste Internationale.

“It’s like free speed,” said Frey, a junior. “And in cycling, every second counts.”

Frey speaks from experience — in July, he won the 2007 U.S. Espoir National Time Trial for men under age 23 by 1.3 seconds.

His passion for cycling began when Frey was 14, growing up in Des Moines, Iowa. He got his first mountain bike, he recalls, and immediately became “obsessed” with the gear.

“We call it ‘getting geeked out’ in the cycling world,” he says. “So, I guess I would say I was an engineer before a cyclist. The cool gadgetry of cycling got me interested in the sport.”

A mountain-biking buddy introduced him to racing the following year. Frey promptly took sixth place at the junior national championship, and that was it. He was hooked.

After arriving at Princeton, Frey began to apply his engineering skills to his cycling. His extensive research pervades his cycling equipment, from the helmet he purchased to match his riding posture to the silicon gel between his wheel rims and tires that subtly changes the shape of his tires, making them more aerodynamic.

Even his own performance is subject to rigorous analysis. During tests in the bike room in Dillon Gymnasium, with his bike on stationary mounts and recordings of previous Tours de France on the television in front of him, Frey measures all aspects of performance. Distance and speed are just the beginning: He also records cadence and power output and creates complex graphs of the data to analyze his rides. He posts his training and performance results, along with details about various races, on his blog.

After a hard midday ride, Frey hangs up his bike and checks the power meter one last time. Photo by Denise ApplewhiteAll the top professional cyclists obtain similar information about their own performances, but they don’t usually do the analyses themselves. Frey prefers it his way, feeling that it gives him an extra edge as he strategizes for upcoming races.

During this summer’s national time trial race, his average speed was around 30 miles per hour for just about 30 minutes. He calculated that his average power for a 15-minute period during the race was 377 watts, just over half of a horsepower. This performance landed him a chance to compete in the Sept. 26 world championship time trial in Stuttgart, Germany.

In preparation for the competition, Frey conducted a series of tests to determine his best racing strategy. The day before leaving for Germany, he simulated riding up a major hill on the actual race route.

“I wanted to determine the maximum intensity I can put out when I’m going up the hill without overdoing it,” he said, after finishing the test. “If I figure out the power output I should maintain, it’ll be kind of like playing a little video game at the race — staring at my power monitor as I go up the hill. If you don’t know how hard to go, it’s easy to hit the hill way too fast and your legs’ll be toast by the time you get to the top.”

At the world competition, Frey had the opportunity to share rides and meals with some of the top cyclists in the world, including fellow Iowan Jason McCartney and Dave Zabriskie. Zabriskie is one of only three Americans ever to wear the leader’s yellow jersey in the Tour de France.

“It’s so amazing to see that these guys are doing the same thing I’m doing — they’re just bike riders,” he said. “It’s so inspirational. They show you that if you’ve got some talent and luck, and if you stick with it, you can get to their level. McCartney trained on the same awful roads that I did in Iowa — it’s so cool to think about what is possible.”

Spending time with these professional riders and hearing about their past competitions helped shape the way that Frey reacted to his performance at the world championship, where he took 57th place.

“At first, I was really disappointed, mainly because I felt like I let down all these people who were supporting me — my parents, the U.S. team, the mechanics,” he said. “But then, I realized that they understand that everyone can have really amazing rides and really bad rides, and so then I was really happy that I got to worlds in the first place. And then, right away, I started to think about what I’ll do differently next year — because I plan on getting there again next year.”

His plan for his future extends beyond training strategies to professional ambitions that combine his interests in engineering and cycling. His goal is to start a company that designs cycling gear, accessories and gadgets that push the limits of speed or enhance the sport of cycling. He is honing his product design and marketing skills this semester in “Entrepreneurial Engineering,” a course taught by Daniel Nosenchuck, an associate professor of mechanical and aerospace engineering.

Frey previously gained valuable experience in product design this summer in an internship at Ball Aerospace and Technologies Corp. in Boulder, Colo. Working with a team of engineers, Frey helped design the electronics packaging for a future satellite.

“I approached it the same way I’ve been taught to approach problems in engineering classes, by being open to nontraditional solutions,” he said. This open-minded attitude allowed him to contribute new ideas to a team of many longtime engineers.

With the world championship behind him, Frey took an unprecedented two weeks off from riding his bike, even just to class. Though his newfound, albeit brief, status as a pedestrian resulted in his being late to class a time or two, he said it was the best way to recover from the tough summer of racing and ready his body for next year’s competitions.

During his normal cycling regimen, he’ll spend between 20 and 25 hours on his bike each week, often riding with his teammates on the cycling team. At other times, he’ll take off by himself, with no firm plans for where he’ll ride, not sure of much more than how long he plans to spend on his bike. His circuitous routes often take him through the New Jersey towns of Frenchtown and Ringoes, or across the Delaware River to Doylestown, Pa.

“I don’t start out with a laundry list of things to do, because then it feels more like a job and I want to enjoy what I’m doing,” he said. “It’s not that complicated,” he added, before sharing his personal philosophy: “Get on the bike and ride.”

Frontiers of health: Sight for sore eyes
Ultra-short laser pulses may allow easier LASIK
by Hilary Parker

Szymon Suckewer needs eye surgery, but he’s not going under the knife just yet—he’d rather wait until no knife is necessary. Having recently developed an incision-free eye surgery technique, he’s confident that will soon be an option.

Szymon Suckewer (center) takes an up-close look at the laser that may one day sharpen his vision. He is part of a five-person team, which includes Alexander Smits (left) and Richard Register (right), working to develop better eye surgery techniques. Photo by Frank Wojciechowski

The breakthrough hinges on the use of femtosecond lasers, which deliver ultra-short pulses of light. Suckewer, professor of mechanical and aerospace engineering and co-director of the Program in Plasma Science and Technology, pioneered the development of these powerful devices in the 1990s.

The applications of the lasers for eye surgery were developed by a five-person team that includes Suckewer, chemical engineering professor Richard Register and Alexander Smits, professor and chair of mechanical and aerospace engineering. The three work closely with ophthalmologist Peter Hersh ‘78, director of cornea and refractive surgery at the University of Medicine and Dentistry of New Jersey, and Peter Frederikse, an assistant professor of pharmacology and physiology at UMDNJ.

Current LASIK (Laser-Assisted In Situ Keratomileusis) surgery requires removal of a flap of the cornea before a laser (which produces a much longer blast of light than a femtosecond laser) is used to reshape the inner part of the cornea. Surgery done with femtosecond lasers will feature more precise cuts and eliminate the need for a flap, since they can create and travel through small channels in the cornea.

“The difference is like cutting with a pair of dull scissors versus a precise scalpel,” Suckewer said. “And, because it generates less heat and there’s no flap, there is also a much faster recovery period.”

The team also plans to use the ultrashort pulse lasers to enable the first surgical cure for presbyopia, the age-related vision loss that occurs as the lens stiffens and the muscles that focus it weaken.

Register’s materials science skills led to the creation of a polymer that can be used to replace old and damaged lens tissue. Since the substance is a liquid that rapidly gels to a solid, it can be injected through the small channels made by the laser. Smits’ expertise in fluid mechanics was critical in the development of a process to remove damaged portions of the lens and replace them with the polymer.

“It was important to match the physical properties of the lens with the polymer,” said Register, who directs the Princeton Center for Complex Materials. “This substance is chemically different, but it matches the stiffness and refractive index of the lens, so it focuses light in the same way.”

The new technique for flapless FemtoLASIK cornea reshaping will soon be tested on animals and then humans, and could be ready for use in hospitals within three to four years. The researchers are considering starting a company based on their work and are currently in discussions with potential investors. The team’s other projects include the development of a liquid bandage for corneal abrasions and the use of femtosecond lasers to reshape contact lenses.

Article Courtesy of: Princeton’s School of Engineering

With ongoing and trying debates dealing with the issue of stem cell research, it seems that such a future is moments away and yet still too far. The ability to understand certain diseases, clone body parts, and replace amputated or missing parts, are few of the many positive aspects that we expect from the continuing efforts in this field. However, in the mean time, a few companies are perfecting a different art of replacing limbs with prosthetic limbs. One special company, Touch Bionics, has taken the liberty to broadcast its success stories with its i-LIMB system. In recent news, for example, an Iraq war veteran was given the chance to experiment a new artificial arm, triumphing into a new era of biomaterial revolution. Able to provide a service to those who had helped us in a time of need, we can only hope to further such a pioneering innovation.

Sergeant Juan Arredondo is a brave man, who unfortunately, was affected by the protracted terror in Iraq. He and three others were exposed to a bomb two years ago, costing the young man his hand. Lindsay Block is another woman who had lived with prosthetics her whole life, having been born without an arm at birth. John German faced the grim circumstance of being diagnosed a bit too late with the thoracic outlet syndrome and was forced to have his hand amputated from his body. Such examples serve as a horrid reality for a few of these people who have dealt with prosthetics , including the myoelectric hand. This hand is what allows these men and women to cope with their lives, but of course, with some difficulty. After having been fitted with the i-LIMB hand, their lives have changed only for the better. So let us unravel the knowledge behind this product- a product leading people toward happier and healthier lives!

Touch Bionics was founded on an idea that developed back in 1963, at the Princess Margaret Rose Hospital in Edinburgh. Thorough research was conducted for children affected by Thalidomide,. After a brief hiatus, the research continued in 1988 to create arms, shoulders, wrists, and hands. Throughout the nineties, the partial hand system started to receive recognition internationally and led to many awards in the coming years. Touch EMAS (EMAS standing for Edinburgh Modular Arm System) was then established, soon to be changed to Touch Bionics that included a technology appeal for its consumers. Now responsible for the i -LIMB hand as well as the ProDigits, together both products are able t o provide enhanced lives for those who use them.

The i-LIMB hand is a unique prosthetic hand that not only models the similar physical features of a natural hand but also the sensitive gripping and holding aspects. Using high strength plastics, the hand is lightweight yet strong, providing the best combination for its customers. Combining the old with the new, the i-LIMB system uses a two-input myoelectric (muscle signal) to open and close the hand’s life-like fingers. An electric signal is produced from the muscle that activates the Myoelectric controls. Looking further into the design, the ProDigits, or the individual fingers, are able to model the movements of regular fingers. Their unique design even allows for consumers to easily remove and replace each finger in the case of damages or other emergencies, unlike old myoelectric hands that force the person to wait extended periods of times.

An important feature of the i-LIMB hand is the gripping ability that a normal hand would posses, but as in all efforts mimicking the human body, requires a great deal of effort to emulate. Starting with the thumb, a part of the human body that has encouraged our dominance on this planet, it is able to rotate into many of the same positions. The gripping features are simply controlled again by the signals that our body emits, which allow for a person to adjust the amount of grip needed to hold an item. A few types of grips that we take for granted that this i-Limb can imitate, include the key grip (thumb closes down onto the side of the index finger), the power grip (all fingers and the thumb close down together), the precision grip (index finger and thumb meet), and index point (thumb and fingers close but the index finger remains extended).

So now we have this amazing figure of a hand that can copy most if not all the movements of a hand, but also looks like a real hand. Touch Bionics accomplishes this feat via two methods that can satisfy any patient. The first is through the unique i-LIMB skin, which fits like a glove over the robotic fingers and hand. The other way is with high-definition cosmesis, which includes blending the hand anatomically with the rest of the body to augment a more natural look. The skin itself is a conglomeration of efforts that were developed to project a breakthrough in the lifelike material.

This hand is a stepping stone in the mechanical sense, but would not be considered a success without the background technology that accompanies the product. As Touch Bionics explains, “Two small metal electrode plates, which detect the minute electrical signals generated by the remaining muscles in the limb stump, are placed against the skin to pick up signals.” Most patients who have an amputated limb experience a phantom feeling, emitting signals as if that limb still existed. Such signals are what trigger the hand to move and allow for patients to adjust to the feeling of a hand accordingly.

Allowing for individuals to continue their lives and blend back into society are usually dreams for those who have undergone such a terrible event. As some of Touch Bionics executives have stated, ““We are delighted that this world-breaking technology which emanated from NHS [National Health System] Scotland has reached this important milestone of commercial acceptance.” For those wishing to contribute this area of technology, the company and many like it, are looking for training and occupational therapists, sales and business development experts, and of course, electro-mechanical engineers. Such a hand takes hours of work, many minds of creativity, and a motivation to help those truly in need- perhaps the opening of this gateway will only instigate the excellence to continue!

Learn more: www.touchbionics.com

I know we have all been in that situation, either in a bus, train, or classroom, when that one miscellaneous cell phone starts to buzz. Quickly a sea of heads looks right, left, behind, and in front if not having sought down into their own bags or pockets, trying to find this vibrating mobile. Now that everyone in the civilized world has acquired this device, unless your ring tone resembles Buy U A Drank or Summer Love, it might be a little embarrassing to put one of those pre-recorded tunes that Verizon downloaded into your phone. Sometimes you just have to vibrate like everyone else in the room. So what makes a phone vibrate that perfect pitch?

The process is very simple, as Howstuffworks.com performed an autopsy on a Tickle-Me-Elmo to discover this exact answer. The doll’s shaking is comparable to a phone’s vibration, which can be explained through the interaction between a quaint flywheel motor and a weight. The weight, approximately that of five nickels, is attached off-center on a gear. As soon as the motor instigates the gear-weight system to turn at speeds of 100 to 150 RPM, a vibration action is immediately caused. This system would be replicated in a smaller version to fit inside your cell phone, but the principles and setup remains virtually the same.

In the end, you always are forced to silence or vibrate your phone when you enter a movie theater or a lecture. And despite your impassioned desire to listen to T-Paine and JT, social etiquette demands otherwise. At least now, you know what happens as you search for your vibrating phone, gears, weight and all!