MOVE OVER HYDROGEN, MAKE WAY FOR MAGNESIUM POWER

Magnesium burns as a white hot flame in fireworks.

•      Magnesium could work better than hydrogen in fuel cells.

•      There's enough magnesium in seawater to provide energy for 300,000 years.

 "When people talk about alternative energy, hydrogen often comes up. How about magnesium? We’ll see. Today, on Engineering Works! Listen to the podcast."

 

Magnesium is nifty stuff. Pure magnesium is a silvery metal, and you probably remember from high school chemistry that it burns with a hot white flame.

 

While a lot of research has already gone into using hydrogen to store energy, either directly as a fuel or as part of fuel cell systems, some researchers think we should be looking at magnesium as a way to store energy. Magnesium stores about 10 times as much energy as hydrogen. And there’s enough magnesium in seawater to provide energy for 300,000 years

 

Engineers at a Canadian company are working on a fuel cell that uses magnesium, air and water to produce electricity. An Israeli researcher has come up with a magnesium-based battery sort of like the rechargeable lithium-ion batteries we all know about. And a California researcher is working on a way to use magnesium to produce hydrogen for fuel.

All of this sounds good, but there’s a problem. It takes a lot of energy to purify magnesium to a form we can use. Maybe more than we’d get back. One researcher in Japan thinks he has the answer: solar energy to power a laser that would give us the almost 6,700° F. heat needed. We’ll see how that turns out.

Our magnesium power is somewhere in the future, so we’re done. See you next time.

Engineering Works! is made possible by Texas A&M Engineering and produced by KAMU-FM in College Station.

 

rubber balls bounced: MATERIALS ENGINEERING, LONG AGO

Just about everybody’s bounced a rubber ball. But making that ball bounce the first time was quite an accomplishment. Who did it? We’ll see. Today, on Engineering Works! Listen to the podcast.We’re used to high-tech materials. Lightweight composites. Super strong adhesives. Polymers that shift shape on command. And it’s easy to think that coming up with new materials or changing old ones is something new. It’s not. 

Take latex, or rubber, for instance. Charles Goodyear invented the process we call, vulcanization, in 1839. Before that, rubber was sticky stuff that got soft in heat and stiff in cold. Goodyear’s process gave us the tough rubber that we use in everything from tires to rubber boots rubber bands. Goodyear’s process was important, but the Mayans in Central America were probably the first to understand how to change latex into more useful forms. And they did it hundreds of years before Goodyear. Mayans mixed latex with juice from the morning glory plant and got rubber that they used for all sorts of stuff. Rubber balls. Rubber bands. Rubber sandals. 

"Rubber statues. Adhesives, glue.The interesting part of this is that each of these things uses a different kind of rubber. Bouncy for balls. Tough for sandals. Sticky for adhesives. What they got depended on how much of morning glory juice they added to the raw liquid latex. But they did it and it worked.We’ve done it for today and it’s time to bounce out of here. See you next time."

NASA with space telescope !!

How Real Satellites/Space Telescopes Come About
A December 2007 artist's conception of the James Webb Space Telescope.Credit: NASA › Larger imageIt takes years to bring a real large space telescope from basic concept to hardware reality. First, a scientist comes up with an idea to study some aspect of the Earth or the cosmos. The idea is discussed, reviewed and developed by committees of scientists. It is proposed to NASA, who makes decisions on what missions to go forth on, and which missions to pass on. If a mission is selected for study a timeline is created to develop the mission.

One of the most difficult aspects of creating a new mission is convincing others to fund it. Once a mission is funded, the team of scientists and engineers "pitching" the mission can then investigate how it could come together. Later, NASA usually selects a prime contractor to help design the telescope and other systems that will fly on the satellite. Northrop Grumman was selected to build components for the Webb telescope. The instruments, or cameras, on the telescope are selected as well, with teams of scientists to watch over the design.

The design process usually includes a number of different designs, which are all tested to see which would yield the best result for the type of object the instrument would study. For example, various types of infrared cameras may be developed and tested, and the one that gives a scientist the best result, would be chosen to be built as a test unit.
Engineering Test Units
The life-sized James Webb Space Telescope model sits in front of the Royal Hospital Kilmainham, in Dublin, Ireland.Credit: Richard Bent, Northrop Grumman Space Technology › Larger imageEngineering test units, or ETUs are created before an actual instrument is built, so that engineers and scientists can make sure it would work properly. ETUs are a replica of the flight unit that can perform certain flight functions for testing purposes. ETUs are also used when engineers are practicing installation of an instrument into a satellite's mainframe or "bus." The outcome of the tests on ETUs may lead to a change in handling procedures of the actual flight instrument, but not a change in its flight construction.

Once the ETUs test successful, then the actual instruments that will fly aboard a satellite or space telescope can be manufactured. Those instruments go through their own set of rigorous tests by the manufacturing contractor, NASA and other partners. On the Webb telescope, NASA is partnering with the European Space Agency and the Canadian Space Agency.
Testing the System

Satellite and space telescope instruments can endure harsh temperature swings as big as 200 degrees Fahrenheit, micro-meteor impacts and exposure to solar radiation. On top of that, before a spacecraft like the Webb can operate in orbit, it has to survive a ride on a rocket to get there. That's where environmental testing chambers like the ones at NASA's Goddard Space Flight Center in Greenbelt, Md., come into play. Hardware gets run through NASA Goddard's centrifuge, acoustics and thermal vacuum chambers to ensure they can endure the rigors of launch.

The centrifuge simulates the increased feeling of gravity's pull during a launch. For astronauts, that's normally a few minutes at two or three times the force of Earth's gravity, measured in Gs. The Webb telescope can experience 6-7 G's due to the Ariane 5 rocket's combined acceleration and vibration. The Webb telescope will be launched on an Ariane 5 ECA rocket. The launch vehicle is part of the European contribution to the mission.

Launching a rocket carrying a satellite or space telescope creates extraordinarily loud noise, so engineers use an Acoustic Test Chamber to make sure an instrument can handle it safely. In Goddard's 42-foot-tall chamber, technicians expose payloads to the noise of a launch. To do that, they rely on 6-foot-tall speakers. The speakers (more accurately called horns) use an altering flow of gaseous nitrogen to produce a sound level as high as 143 decibels for one-minute tests. That's about the level of sound heard standing next to a jet engine during takeoff.
This panorama shows the inside of Goddard's High Bay Clean Room, as seen from the observation deck. The clean room will be a home to some Webb components before the telescope is put together. Credit: NASA/Chris Gunn › Larger image 

The hardware is also tested in the thermal vacuum which exposes them to conditions they will experience in space. The chamber has massive mechanical vacuum pumps and cryopumps to ensure that the hard vacuum of space is simulated in the test chamber. The cryopumps use gaseous helium to condense remaining gases out of the chamber once the mechanical pumps have done their work. The two types of pumps work together to eliminate all but the tiniest trace of air in the chamber, down to about a billionth of Earth's normal atmospheric pressure.

Because the Webb telescope is operating in the infrared portion of the electromagnetic spectrum it is designed to operate at very cold temperatures. To simulate this environment an additional cooling system, a helium refrigeration system, was added so the thermal vacuum chamber could reach temperatures in the -413 Fahrenheit (F) range. "The ISIM structure was tested in our thermal vacuum chamber down to about 26 Kelvin, or minus 413 F," said Jon F. Lawrence, Webb telescope Mechanical Systems Lead Engineer/Launch Vehicle Liaison at NASA Goddard.

This test program starts at the lowest level of assembly, instrument or spacecraft components and is repeated at each next level of assembly. Once the instruments pass these tests they are all put together into the structure which holds them and the unit is tested again. The instrument structure is connected to the telescope and the whole observatory is tested yet again. There isn't a vacuum chamber large enough to hold the entire Webb observatory at NASA Goddard, so the telescope will travel to NASA's Johnson Space Center in Houston, Texas, to be tested in a chamber that was originally built for testing the Apollo command module to simulate the trip to the moon. The next stop after that is launch into deep space.

Currently, ETUs or actual flight hardware for the Webb telescope are being tested in various ways.

The James Webb Space Telescope is the next-generation premier space observatory, exploring deep space phenomena from distant galaxies to nearby planets and stars. The Webb Telescope will give scientists clues about the formation of the universe and the evolution of our own solar system, from the first light after the Big Bang to the formation of star systems capable of supporting life on planets like Earth.

The Webb Telescope project is managed at NASA's Goddard Space Flight Center in Greenbelt, Md. The telescope is a joint project of NASA, the European Space Agency and the Canadian Space Agency.

For information about NASA's James Webb Space Telescope, visit:
http://www.jwst.nasa.gov/

To see photos of the Full-scale model on the National Mall in Washington, D.C. May 10-12, 2007, visit:
http://www.flickr.com/photos/scifilaura/sets/72157600211237270/

Rob Gutro
NASA's Goddard Space Flight Center, Greenbelt, Md.

THE LATEST NEW FIBER OPTIC TECHNOLOGIES !!

Baseband video consists of one video picture being sent point-to-point, such as the video output of a VCR to the video input of a monitor. Figure 1 illustrates simple point-to-point transmission. There exist two levels of service for baseband video: broadcast studio and consumer. These types describe, primarily, the quality of the signal. Broadcast studio quality requires a much higher signal fidelity, while consumer quality baseband requires is less demanding. In addition to the difference in signal fidelity, there is also a difference in the connectors typically used for the transmission of these signals. The broadcast baseband applications typically use a BNC connector and the consumer baseband applications typically uses an RCA connector.
 
 Baseband Video Signals
The most basic form of a television signal is a baseband video signal, also referred to as a composite video signal. In an AM baseband system, the input signal directly modulates the strength of the transmitter output, in this case light. The baseband signal contains information relative to creating the television picture only. The following information is carried on a baseband signal:

• Scanning: drawing the television picture
• Luminance: the brightness of the picture
• Chrominance: the color of the picture

The creation of the baseband signal produces a range of frequency components. The highest frequency in a baseband signal is also its bandwidth. The lowest frequency ranges close to zero Hz or DC. The video output of a television camera or video tape recorder has its highest frequency, therefore, its bandwidth, at either 4.2 or 6 MHz, depending on the type of TV format used. Looking at an actual baseband signal, illustrated in Figure 3, we can see that the camera and the video display are scanned horizontally and vertically. The horizontal lines on the screen are scanned alternately, with the odd numbered lines first and the even numbered lines second, or vice versa. (Figure 3B depicts the initial scan of the odd numbered lines.) This method is known as an interlacing system. The second method is to scan the lines sequentially; this is known as progressive Scanning. The camera and receiver must be synchronized when scanning and reproducing an image. The horizontal and vertical sync pulses regulate the synchronization of the camera and receiver, illustrated in both 3B and 3C, and starts a horizontal trace. As seen in Figure 3A, during the horizontal blanking interval, the beam returns to the left side of the screen and waits for the horizontal sync pulse before tracing another line. The dotted line illustrated the horizontal retrace. When the beam reaches the bottom of the screen, it must return to the top to begin the next field. This is called the vertical retrace, which is signaled by the vertical sync pulse illustrated in Figure 3C. The vertical retrace takes much longer than the horizontal retrace, therefore, a vertical blanking interval ensues to synchronize the two signals. During both the horizontal or vertical blanking intervals no information appears on the screen. (from http://fiber-optic-tech.blogspot.com)

How Clutches Work ? ? ??

If you drive a manual transmission car, you may be surprised to find out that it has more than one clutch. And it turns out that folks with automatic transmission cars have clutches, too. In fact, there are clutches in many things you probably see or use every day: Many cordless drills have a clutch,chain saws have a centrifugal clutch and even some yo-yos have a clutch.

In this article, you'll learn why you need a clutch, how the clutch in your car works and find out some interesting, and perhaps surprising, places where clutches can be found.

Clutches are useful in devices that have two rotating shafts. In these devices, one of the shafts is typically driven by a motor or pulley, and the other shaft drives another device. In a drill, for instance, one shaft is driven by a motor and the other drives a drill chuck. The clutch connects the two shafts so that they can either be locked together and spin at the same speed, or be decoupled and spin at different speeds.

In a car, you need a clutch because the engine spins all the time, but the car's wheels do not. In order for­ a car to stop without killing the engine, the wheels need to be disconnected from the engine somehow. The clutch allows us to smoothly engage a spinning engine to a non-spinning transmission by controlling the slippage between them.

To understand how a clutch works, it helps to know a little bit about friction, which is a measure of how hard it is to slide one object over another. Friction is caused by the peaks and valleys that are part of every surface -- even very smooth surfaces still have microscopic peaks and valleys. The larger these peaks and valleys are, the harder it is to slide the object. You can learn more about friction in How Brakes Work.

The 6L50 transmission is a Hydra-Matic six-speed rear and all-wheel drive automatic transmission produced by GM 

Workers assembling a new transmission at the button up section. 

How Removable Storage Works ??

Removable storage has been around almost as long as the computer itself. Early removable storage was based on magnetic tape

 like that used by an audio cassette. Before that, some computers even used paper punch cards to store information!

We've come a long way since the days of punch cards. New removable storage devices can store hundreds of megabytes (and even gigabytes) of data on a single disk, cassette, card or cartridge. In this article, you will learn about the three major storage technologies. We'll also talk about which devices use each technology and what the future holds for this medium. But first, let's see why you would want removable storage. 

An employee of Samsung Electronics shows a 32-Gigabyte NAND memory card and chip. Memory cards are typically found in devices such as digital cameras while memory chips can hold RAM and ROM in computers. Next, see a computer memory wafer.