Posted by Stuff Blogger in Why don't we live underground? on Saturday, July 25, 2009
Why don't we live underground?
Washington serves as a catchall term for the seat of power in the United States. It's taken on a single collective identity, as in "Washington's decision to send a senior diplomat to nuclear talks with Iran" [source: Reuters]. Canada has a catchall town too -- Ottawa -- and during the Cold War, Washington and Ottawa worked closely to defend their shared continent from Soviet attack.
The one and only way in or out of NORAD's Cheyenne Mountain control center.
The most prominent result of this joint defense venture was NORAD, the North American Aerospace Defense Command. Cultivated from a three-tier radar detection system spanning Canada from its southern border to the Arctic Circle, NORAD was an integration of both nations' detection systems into one comprehensive network. It was helmed through two controls centers: one in Canada and one in the United States. Washington placed its high value target inside one of the most secure locations on earth -- deep within Cheyenne Mountain in Colorado.
After carving out 700,000 tons of the mountain's granite innards and securing the only egress into the command center with two 3.5-feet thick steel blast doors, the U.S. military was confident the base could withstand a direct nuclear strike [source: The Gazette, DTIC].
The confidence in the security afforded by subterranean structures isn't exclusive to the United States. Chairman Mao constructed an underground city beneath Beijing following a border dispute with the Soviets in 1969. In the current unpolarized world, the seats of power are splintered, with the most powerful wielding information rather than intercontinental ballistic missiles. But the mentality that subterranean equals security has remained a constant.
There are companies that operate the networks the citizens of the world use to circumvent the Internet. And there are others that maintain those same people's credit histories and other sensitive information. Both of these powerful industries have determined that subterranean locations are the best sites to store their golden geese. Underground structures are less susceptible to physical intrusion and natural disaster. They also offer constant temperatures, and since subterranean buildings aren't susceptible to the fickle nature of aboveground weather, they require less energy.
One wonders with the benefits offered underground why we don't live there.
Underground Living: A Slap to Darwin's Face
We construct our houses aboveground and our skyscrapers into the air for a reason. Mostly it's because we were designed (or evolved) to thrive in the topside environment. We gain physical and mental health from the sun, air and flora and fauna we share the aboveground world with. Should a massive shift to subterranean dwelling take place among humanity, we would essentially be challenging evolution to do its worst. And evolution's worst generally results in costly damages to a species -- like extinction, say.
Humans are diurnal creatures, meant to be active when the sun's up and asleep at night when it goes down. We actually have a circadian rhythm, a biological clock that dictates our slumber patterns based on the cycle of the sunrise and sunset. We're inextricably dependent on the sun.
Nineteen-year-old Shao Ling struggles with rickets, which has kept her height at about two feet (06.m). She suffers from congenital rickets, but the developmental disease can also be the result of a vitamin D deficiency.
That link becomes clear through vitamin D. This essential ingredient for human physiological function prevents rickets (improper and weak development of bones) in children and bone loss in the aged. It's also been linked to metabolic and immune system function and reduction in hypertension. So we need vitamin D , and the curious part is that it's the only vitamin humans require that we don't derive from other sources like food or Vitaminwater. We actually produce vitamin D within our cells through photosynthesis, a process that's impossible without ultraviolet radiation (UVR) accepted from the sun through our skin.
We also produce serotonin through sunlight. This hormone is largely responsible for our positive moods, and people who don't produce enough due to a lack of exposure to sunlight can become depressed, a condition referred to as seasonal affective disorder (SAD).
Air is another important ingredient for proper functioning of the human body. Above ground, it's found in aces. The human lung has developed to accept the mixture of elements (mostly nitrogen, some oxygen and traces of argon and carbon dioxide) at the atmospheric pressure found around sea level. Dwelling too long tens or hundreds of feet below sea level, like via scuba, can result in the components of air separating from the blood, becoming bubbles. This creates the life-threatening situation called the bends. The same pressure from the force of gravity is found in the Earth's crust just as it is in the oceans. Miners must utilize the same type of decompression staging as they return to the surface, and, upon rescue, trapped miners are hurried off to a decompression chamber to readjust to sea level atmospheric pressure in the same way rescued divers are.
Of course, there's something to be said for adaptation. Without it, evolution wouldn't exist at all, and a move underground would simply accelerate the process. On the other end of the atmospheric pressure spectrum, generations of humans who've lived at high altitudes, like Tibetans and Andeans, have acclimated to the thinner air. They've adapted to derive more of the scarce oxygen from the air into the bloodstream than sea-level denizens. Underground, our fellow mammal, the mole, evolved to produce and circulate a larger amount of blood and oxygen-rich hemoglobin than similarly sized aboveground counterparts.
Humans could arguably thrive below ground using our most favored adaptation tool: technology. Why wait for eons of evolution to take place and risk the whole survival of the fittest aspect when we can simply whip an environment into the one we desire?
That's precisely what some people who've made the move underground have been forced to do. Rather than adaptation, however, it's generally viewed as addressing design challenges.
Earth-sheltered Homes: How Deep is Your Love?
The fantasy-drenched concept of a race of humans living below ground is actually an old one. Indigenous tribes have long recognized the climatological and security benefits afforded by living underground. Modern versions of these dwellings are already underway in some quarters. Homes are being constructed below ground, as are other facilities, like the underground Marin County Jail, designed by legendary architect Frank Lloyd Wright. In creating these subterranean dwellings, measures are being taken to ensure a future sketch of humanity doesn't depict sheet-white, blind creatures that suffer from rickets and crippling depression and subsist on a diet of worms plucked from dirt walls. Even when living below ground, we must find ways to harness the essentials that we need to survive.
This modern subterranean dwelling is a fresh take on an ancient idea.
Water's not a problem; 30 percent of the freshwater on Earth can be found underground at any given time in the form of aquifers. This source is constantly replenished by precipitation trickling through the soil, which acts as a purifier [source: USGS]. Air doesn't operate the same way as water below ground. The density of soil makes it difficult to breathe, and less air is found below ground, which explains why you suffocate shortly after being buried alive.
This little problem and the need for sunlight are addressed through the atrium or courtyard design of earth-sheltered homes. These homes are built below ground on all sides, save for an entrance that usually looks like a door planted in the side of the hill. The only exposed area of the structure is a central atrium or courtyard, which allows air and sunlight into the home. In subterranean homes without any exposed areas, ventilation systems and shaft skylights serve the same purposes as an atrium.
Sunlight will stream into a much more massive underground structure in Japan through a pair of covered domes, the only feature that will divulge the subterranean city beneath. Due to their immense population sharing a proportionately small land mass, the Japanese are unsurprisingly at the cutting edge of underground construction. Their biggest project is the double-domed Alice City, based around two central shafts plunged 500 feet (152 m) below ground. The shafts allow light to enter and serves as the nucleus for an ant farm of office space, entire shopping malls and residences. Necessities like ventilation, power generation and waste are all handled on-site below ground [source: Time].
Alice City is not yet constructed, though slightly less ambitious projects are operating around Japan. Through ventures like underground offices and shopping malls, the Japanese are hammering out the problems with subterranean living. A television studio 66 feet (about 20 m) beneath Tokyo's street level addressed the problem of a sense of isolation among workers by simulating the weather aboveground. A fire in the subterranean mall that took the lives of 15 people in 1980 taught designers to keep the air thinner to reduce smoke and invest more heavily in fire sensors and sprinkler systems in underground structures than they do in aboveground ones [source: Time].
The Japanese are also hammering out the intricacies of growing food below ground through the Pasona O2 project. The Pasona staffing agency created a working underground farm in an unused bank vault located beneath the company's offices, five stories below ground. Using hydroponics and artificial lighting systems, the company is successfully growing crops like tomatoes, strawberries and rice [source: Trends in Japan].
Population trends suggest the globe will experience as many as nine billion people packed across its surface by 2050 [source: U.S. Census Bureau]. With space aboveground at a premium, subterranean living could become more than just viable, it may become a necessity.
Posted by Stuff Blogger in Technology, Top 5 Energy-efficient Computers, Top 5s on Tuesday, July 21, 2009
Top 5 Energy-efficient Computers
5: Dell Studio Hybrid
Dell calls the Studio Hybrid its greenest consumer desktop, and both Energy Star and EPEAT give it the thumbs up. The Studio Hybrid's 87-percent-efficient power supply meets Energy Star's 4.0 green computing standards, and EPEAT gives the system its highest rating, gold.
The Studio Hybrid is 80 percent smaller than a typical desktop computer and uses about 70 percent less power than most standard desktop computers. The computer's packaging is made from 95-percent-recyclable materials and comes with less printed documentation -- 75 percent less by weight (all documentation is made available online instead) [source: Dell].
For an additional charge, you can personalize it with a bamboo sleeve. And when you're ready to upgrade, the Studio Hybrid comes with its own system recycling kit.
4: Dell OptiPlex
Dell's OptiPlex line is a solid choice for professionals looking for an expandable, scalable desktop. It's also an energy-efficient workhorse -- the OptiPlex is Energy Star 4.0 compliant and carries an EPEAT gold rating.
It's not only the computers that are going green at Dell -- the U.S. Environmental Protection Agency (EPA) ranks Dell in the top five in the latest EPA Fortune 500 Green Power Challenge [source: EPA]. Dell is committed to reducing its desktop and laptop energy consumption by up to 25 percent by 2010 through the use of integrated Energy Smart technologies, including energy-optimized hardware and software. Since 2005, the OptiPlex's energy efficiency has improved by about 50 percent [source: Business Wire].
3: Lenovo ThinkCentre M58 / M58p
Like their green brethren, ThinkCentre desktops are Energy Star 4.0 compliant and have earned the EPEAT gold rating.
What makes the ThinkCentre especially green? Systems using their power-management tools can reduce energy consumption by 69 percent [source: Lenovo]. Lenovo estimates that energy savings translate into a cost savings of $40 on your yearly electricity bill. And it's not just dollars saved, it's CO2 emissions reduced, too. The ThinkCentre is designed to reduce CO2 emissions by 575 pounds (261 kilograms) per desktop every year, which is about the same as if 185 gallons (703 liters) of gasoline went unused [source: Lenovo].
2: Apple 17-inch MacBook Pro
For those in the market for something small and shiny -- and green -- take a look at Apple's 17-inch MacBook Pro. This laptop boasts Energy Star 5.0 compliance and a gold EPEAT rating. The MacBook shines when it comes to reducing environmental impact. It's made out of glass and aluminum (both recyclable materials); is free from mercury, arsenic, PVC and brominated flame retardants; and it uses 35 percent less consumer packaging than its predecessor.
Apple estimates that the 17-inch MacBook uses about 1,499 pounds (680 kilograms) of CO2e (Carbon Dioxide Equivalence, which measures the CO2 emissions potential during a specific period of time) total through its entire lifespan, from production and transportation to consumer use and recycling [source: Apple].
Prefer to work on something larger than a laptop? Apple's iMac is an integrated desktop -- an all-in-one system -- that also rates the Energy Star label and EPEAT gold. When you're ready to upgrade, take advantage of Apple's product take back and recycling programs.
1: Toshiba Portege R600
The Toshiba Portégé laptop line has earned Energy Star 4.0 compliancy and EPEAT's gold rating -- not only did it receive EPEAT's highest rating, the Portégé R600 ranks No. 1 in the gold category. Additionally, Greenpeace named the Portégé R600 the greenest laptop computer in 2009 in its second annual "Green Electronics: The Search Continues" survey.
Toshiba rates its products against an idea it calls Factor T, a mathematical formula the company created to assess a computer's consumer value against its environmental impact over its expected lifetime. High consumer value and low environmental impact equal the biggest energy efficiency.
Toshiba itself has set a company goal to double its environmental efficiency by 2010. Toshiba uses components with low-power consumption technology. Component and part suppliers that want to work with Toshiba must comply with a 22-point environmental performance survey before collaborating with the company.
Posted by Nirav Ashara in Bonus Post, Why do eggs turn hard when you boil them? on Friday, July 17, 2009
BONUS POST
Eggs are rich in protein, especially the egg whites. It's this protein that causes eggs to become hard when boiled. Here's how it works:
Hint
If you don't use a hard-boiled egg (which you must keep in the refrigerator) within seven days, toss it!
Protein is a chain of amino acids. These amino-acid strings fold back on themselves (the way the strings fold determines the protein's chemical and biological properties). The proteins are held in place by weak bonds (non-covalent) between different parts of the amino-acid string. When you break those strings, by various methods, you are denaturing the protein. You can denature a protein in several different ways.
Here are two ways to do it with eggs:
- Heat - When you heat an egg, the proteins gain energy and literally shake apart the bonds between the parts of the amino-acid strings, causing the proteins to unfold. As the temperature increases, the proteins gain enough energy to form new, stronger bonds (covalent) with other protein molecules. When you boil an egg, the heat first breaks (unfolds) the proteins, and then allows the proteins to link to other proteins. As the proteins form these new, strong bonds, the water that surrounded each protein molecule when the egg was liquid is forced out. That's why the egg turns hard. (Heat affects all of the proteins in an egg, so it's the best way to cook an egg.)
- Chemicals - You can also break the weak bonds between protein molecules with chemicals. According to an experiment done by the BBC Science Shack, if you put vodka on an egg white, the alcohol in it breaks weak hydrogen bonds in the protein. If you put vinegar on an egg white, the acid in it breaks ionic bonds. If you mix the two (vodka and vinegar), you break both types of bonds and quite effectively denature the protein. Lots of other chemicals will also break those weak bonds. This won't work as well on the yolk, which, while also protein-rich, has lots of fats and other properties that make it more difficult for it to become hard.
You can do something similar when you whisk egg whites: By exerting mechanical energy in the whisking process, you cause the protein bonds to break, and subsequently re-connect. Once these new, strong bonds are formed, the egg stays in that state. The proteins have formed a network of strong, permanent cross-links. A cooked, chemically-altered or well-beaten egg will never go back to its original state.
When cooking eggs, use moderate heat. High heat causes the protein in eggs to become tough and rubbery. When you use high heat to boil an egg, it causes a chemical reaction between the yolk and the white that leaves a green film around the yolk. That film is iron sulfide, caused by iron in the yolk reacting with hydrogen sulfide in the white. It won't hurt you to eat it, and the egg will taste the same, but it sure looks awful!
Posted by Nirav Ashara in 5 Ways to Avoid Overheating Your Truck, Top 5s
5 Ways to Avoid Overheating Your Truck
Have you ever had the frustration of being stuck in bumper-to-bumper traffic on a hot summer day? Chances are that you have. Sure, it may be hot and humid outside, but you'd better believe that the temperatures under the hood of your truck ar e even worse. That's bad. And if it gets too hot, well, cross your fingers and hope you'll make it home. Why? Quite simply, because heat is the enemy of your truck's engine.
The cooling system in your truck is your engine's front line of defense when it comes to the ongoing battle against heat. If you properly maintain your truck's cooling system and take a few other preventative measures, you're ensuring that your engine won't experience the added stress of operating under extreme high temperatures. But how do you keep your truck's engine running cool under most normal driving conditions? Is there anything that you can do to prevent your truck from overheating?
As it turns out, there's actually quite a bit that you can do. We thought we'd put together a short list of some of ways we discovered. So here are, in no particular order, the top five ways to avoid overheating your truck.
5: Watch Your Temperature Gauge
This may seem like rather elementary advice, but it does warrant a mention because so few drivers actually make a habit of monitoring their truck's engine temperature gauge. Understandably, the fuel gauge is critical for most drivers on a daily basis, as is the speedometer and possibly even the tachometer. But the instrument cluster of your truck can tell you so much more; you simply need to know where to look. Alongside the temperature gauge, you may be able to find an engine oil pressure reading, a battery charge indicator and maybe even a boost and vacuum gauge (if your truck has a turbocharged engine).
Once you've located your truck's temperature gauge, pay attention to what the gauge displays as a normal operating temperature for your engine. The easiest way to do this is to simply take a mental note of the reading on several different occasions after the truck's engine has had a chance to run for a while. If your engine's cooling system is operating properly, you'll find that the temperature should remain fairly stable or at least consistently fall within a certain range. If you see the temperature reading begin to increase rapidly, you may have a problem. Ignoring it won't make it go away, either. It's wise to diagnose and repair an engine cooling issue as soon as possible. If the worst case scenario plays out, you just may be able to avoid a potentially catastrophic engine failure. As you could probably guess, major engine repair or even replacement isn't cheap.
So there you have it: Something as simple as glancing at your temperature gauge could end up saving you a significant amount of money in the long run. Up next, we have another bit of straightforward advice -- nevertheless, it's equally important.
4: Look for Obvious Leaks
One clear indicator of a problem under the hood (or really anywhere on your vehicle) is the presence of fluid beneath your parked truck. But how do you determine if you're seeing coolant and not some other type of fluid? Typically, it's fairly easy to determine the specific type of fluid your truck is losing based on the fluid color and location of the puddle. In years past, all vehicles used engine coolant that was the same bright green color, and it had a very sticky-sweet smell. Now, coolant comes in a variety of colors ranging from the familiar bright green to red, orange and even pink. Different manufacturers have different standards when it comes to the fluids they fill their vehicles with.
At this point, the color of your truck's coolant doesn't matter quite as much as the fact that you've got a leak somewhere in your cooling system. The various fluids that circulate throughout your vehicle's many different sealed systems -- such as your cooling system, engine, transmission, brake system, transfer case and so on -- are meant to stay trapped inside until they're intentionally drained and replaced. Fluids lubricate and cool moving parts within your vehicle, and your truck's cooling system is no exception. To put it in the simplest terms: If you see a puddle of coolant beneath your truck, you have a leak. And if you have a leak, that means you're in danger of running low on (or running out of) engine coolant, which would definitely cause your engine to run hot or even overheat. So, don't delay in getting that leak repaired, or you could end up with a hefty repair bill.
In the next section, we'll find out why it might not be a good idea to add too much water (or too much coolant) to your truck's cooling system.
3: Use the Proper Coolant-to-Water Mixture
Your truck's cooling system doesn't operate on coolant alone, and it can't operate on just water, either. In fact, your truck's cooling system actually requires a mixture of coolant and water to provide just the right level of protection for your engine. If you skew the manufacturer's suggested coolant-to-water mixture by adding only water or adding only coolant, you could risk damaging your truck's engine.
The balance between coolant boil-over temperature and freeze-up temperature actually hinges on the proper mixture of coolant and water. For instance, a mixture that consists of 60 percent water and 40 percent coolant can provide boil-over protection all the way up to 259 degrees Fahrenheit (126 degrees Celsius) and freeze-up protection all the way down to minus 10 degrees Fahrenheit (minus 23 degrees Celsius). If you were to change that mixture to 30 percent water and 70 percent coolant, you would have boil-over protection up to 270 degrees Fahrenheit (132 degrees Celsius) and freeze-up protection down to minus 62 degrees Fahrenheit (minus 52 degrees Celsius).
As a general rule, you'll find that a 50/50 mixture of coolant and water is sufficient for most driving conditions. However, to ensure that you're using the proper mixture, it's a good idea to take a look at your owner's manual.
On the next page, we'll discuss a situation that could easily cause your truck to overheat -- one that a lot of truck owners are guilty of.
2: Don't Overload Your Truck
Seems like a simple rule to follow, doesn't it? But it happens all the time. Just take a look around if you don't believe us. In fact, the next time you're at one of those home improvement warehouse stores, pay attention to how much lumber some people stack in the back of their pickup trucks. Or the next time you're at a landscape supply store, watch how much topsoil or mulch some owners request to be dumped in the bed of their truck. By the time they're ready to drive away, the rear bumper is practically dragging on the ground. But what does that have to do with an overheated engine?
While it may look funny to see a grossly overloaded truck making its way down the road, the damage that driver is likely causing to his or her truck's engine is anything but. As you can probably guess, every part of the truck's powertrain (including the engine) has to work significantly harder to get all of that extra weight rolling down the road -- and keep it in motion, too. All of this extra work means extra heat created by the truck's engine. If the cooling system can't keep up with the demand -- you guessed it, potential severe engine damage.
One simple way to avoid overloading your truck -- and overheating your engine in the process -- is by familiarizing yourself with the manufacturer's suggested weight limits or weight ratings for your specific vehicle. These can be found in the owner's manual or on a decal or plate located on the inside edge of your truck's door frame.
Don't stop now. There's just one more tip that we want to share with you for beating the heat in your truck's engine.
1: Perform Routine Maintenance
Keeping your truck in proper working order is one of the best ways to avoid having your engine overheat. That makes perfect sense, right? To be honest, if you properly maintain your vehicle from bumper to bumper, you'll prevent a lot more than just engine heat issues. However, since that's the main focus here, what areas or components will require special attention to help you avoid an unwanted rise in engine temperature?
As we mentioned earlier, it's a good idea to watch for indicators of a problem in the cooling system, such as sudden jumps in normal engine operating temperature or leaks in the system. You should also regularly inspect your truck's coolant hoses for damage or deterioration. It's also a good idea to inspect any clamps that attach the hoses to the radiator and to your engine. Other areas that you'll want to keep an eye on under the hood include the engine belt (or belts, in some cases), the radiator itself, the radiator cap, the overflow container, the cooling fan and your engine's thermostat, just to name a few.
So there you have it, five relatively simple ways that you can avoid overheating your truck's engine.
Posted by Nirav Ashara in 5 Tips for Restoring Old Furniture, Top 5s on Thursday, July 16, 2009
5 Tips for Restoring Old Furniture
Professional furniture restorers and hobbyists alike all have one thing in common -- the desire to pluck a piece of furniture off the side of the road and restore it to its former glory. And what's not to like? Not only are you saving something from a landfill, but you're breathing life into something that's long been forgotten. All the former owner knows is that the legs of the table are busted, the surface is marred by water rings and it doesn't sit evenly on the floor. What's more, it's taking up valuable space where that new Ikea dining table should go. But what many might see as a space-consuming relic from days gone by, furniture restorers see as a possibility.
If you've never tackled a furniture restoration project, you should know the difference between refinishing and restoring a piece. Refinishing can be as simple as stripping off the top layer of varnish, sanding and applying a new one. Project done. Restoring can involve refinishing, but it can also require a whole lot more -- fixing broken legs, replacing hardware, repairing cracks, replacing trim pieces and fabrics with period detail. Basically anything that's required to get the piece of furniture as close to the original condition as possible is called restoration. Often, it's more than just a facelift -- it has to do with making the item usable again and possibly even adding value. Here are five tips that can help you make the old new again.
5: Research and Inspect
The first step is to do a little research to determine its value, so you know whether or not you should try and restore it yourself. Inspect the piece for marks or labels that may indicate its origin. Even if the piece isn't old but it was made by a master craftsman, it could be valuable. If you suspect that it's worth some money, it's best to consult a professional before proceeding with any work. The library is an excellent resource to help you identify certain periods and styles of furniture, or find a furniture restoration shop and seek out their advice. Take photos of any markings or tags for your records. Removing a collectible antique's finish could lessen or void its value, so hold off on stripping or sanding for now.
There are a few things the novice can look for to determine its age. Feel underneath. If the interior corners are sharp, then it's probably not an antique. Take out a screw and look at the threads. If they have inconsistent widths between them, then it's probably pretty old. These are just a couple of tips -- valuing antique furniture is a much more complicated process that should be performed by a professional appraiser. If you do find that a piece is valuable, you should not only hold off on restoring it, but you also should insure it as soon as possible.
4: Clean Before You Start
Before whipping out your sandpaper and paintbrush, you should give the piece a thorough cleaning. After years of neglect, it's likely to have a patina of dirt and grime. Removing the buildup can reveal a nice finish underneath, so a good cleaning and buffing may be all that old chair needs to sit stately in your living room.
A good place to start is to give it a good scrub with a sponge and some vegetable-based oil soap in warm water. A lot of older furniture is detailed, so you can use a soft toothbrush to get in the nooks and crannies. It's a good idea to remove hardware so you can clean behind it, as well as give the hardware a good shine. Toothpicks are handy for getting between tight spots, but here's a tip -- get a wooden dowel the size of a pencil and buy a pencil sharpener. It's much more solid than a toothpick, and you can keep it nice and sharp for digging out grime. If you need to use steel wool on some stubborn wax buildup, go with No. 0000 and use a light hand. Too much pressure can dull the finish.
3: Repair
The next step is to repair or replace any broken parts. You may luck out and stumble across a comparable leg or knob at an antique store or estate sale, but don't count on it. In most cases, if you want to match what already exists, you may have to get parts custom made. The auction Web site eBay is another option with its robust antiques trade. If you do find or order a new piece of hardware, you may want a professional's help with installation, unless you feel good about your skills as a craftsman. Most people can manage handles and pulls or a drawer in disrepair, but if you're replacing legs or dealing with the structural integrity of the piece, you might need some help.
If the table or chair wobbles, it may simply need some screws tightened. Find the culprit by turning the piece over and inspecting each leg where it meets the body. If it shakes, check out the screws, and if they're in good shape, tighten them down. If they're rusted out, carefully remove and replace them. Small breaks can be joined with wood glue, and if you have any small cracks, use like-colored wood putty. And if you plan to use stain as your finish, make sure you buy a putty that can be stained.
2: Refinishing or Painting
Refinishing the piece means taking off the old finish and creating a new one. It's physically demanding, so be prepared to use some elbow grease. Stripping is a messy and cumbersome job, but the result is rewarding. For a do-it-yourselfer, it's best to use a combination of chemical strippers and sanding. Patience is definitely a virtue during this phase of restoration because some finishes can be stubborn. If you get frustrated and try to speed up the process, you can gouge the wood with a putty knife, leading to more repair work.
There are many different kinds of stain, and each works best with different woods, so be sure to thoroughly research your options before proceeding. If you determine that the wood underneath isn't worthy of staining, you can always paint the surface. Just be very sure it's not a valuable piece, because it sure won't be once you paint it. If you do decide to paint, just sand the finish to smooth out any bumps before you start. Whether you're painting or staining, once you finish stripping and sanding, you'll want to give it another good cleaning. A clean surface is key to creating a professional finish.
1: Tools of the Trade
If you green-light a furniture restoration project, you'll need some tools to make it all happen. Take a trip down the sandpaper aisle first and get a variety of grits. Start with the rough stuff (80-120) and work your way up to the finer grits (400). Get a couple of putty knives, one plastic and one metal. There are all kinds of other furniture scrapers in the same section and you can always give one a try if it feels good in your hand. Grab some No. 0000 steel wool and a liquid stripping gel, and you're on your way to the refinishing department.
You'll need screwdrivers to tighten up any loose joints, both Phillips head and flat head. You should also have a small hammer and a rubber mallet, which will allow you to give the wood gentle reminders without leaving a mark. If you're serious about restoring your piece, you may need to invest in some wood clamps as well. You can buy a variety pack or wait and see what your needs are and buy them individually.
You should also have the following items on hand:
- Wood glue
- Wood putty
- Oil soap
- Measuring tape
- Gloves
- Respirator
- Two to three inch (5.08 to 7.62 centimeters) angled paint brush
- Toothbrush
- Toothpicks
Now that your toolbox is full and you're armed with these tips, you're ready to begin restoring your furniture to its former glory.
Posted by Nirav Ashara in How the Obesity Paradox Works on Tuesday, July 14, 2009
How the Obesity Paradox Works
About 65 percent of Americans are either obese or overweight, and the Centers for Disease Control has classified obesity as an epidemic in the United States. According to NIDDK/NIH, obesity costs Americans more than $117 billion annually in health care [source: NIDDK/NIH]. If you are obese, you have a 50 to 100 percent increased risk of premature death than someone of normal weight. Obesity is a risk factor in other conditions, like high blood pressure, heart disease and type-2 diabetes. However, recent studies have shown that obese people with chronic diseases have a better chance of survival than normal-weight individuals do. This finding has been called the obesity paradox. But before you reach for those extra doughnuts or postpone going on that diet, let's examine obesity.
Obese people have excess body fat. Overweight people have excess body weight (weight includes bone, fat, and muscle). Generally, women have more body fat than men do. Women with more than 30 percent body fat and men with more than 25 percent body fat would be considered obese.
Scientists can measure body fat with X-ray absorption techniques and underwater weighing, which are based on the fact that fat tissue has a different density than bone or muscle. But these methods aren't practical for routine doctor's visits. So, primary health care providers use other methods (like height, weight and skin-fold thickness).
The most popular and convenient method for estimating obesity is the body mass index (BMI). BMI is a ratio of weight to height. This is the formula:
BMI = weight (lb) / [height (in)]2 x 703 (English measurements)
BMI = weight (kg) / [height (m)]2 (metric measurements)
For example, a 5-foot-5-inch, 150-pound woman would have a BMI of 25. According to these BMI categories, she is overweight but not obese.
- Less than 18.5 = underweight
- 18.5 to 24.9 = normal weight
- 25 to 29.9 = overweight
- More than 30 = obese
There are several online charts based on BMI calculations that you can use to categorize your weight.
Obesity affects men and women of all racial and ethnic backgrounds, but women have a higher percentage of obesity than men. In the United States, African-Americans have the highest
percentage of obesity, followed by Mexican-Americans and non-Hispanic whites. Obesity affects about 11 to 28 percent of children, who show the same racial and ethnic obesity patterns. Obesity increases the risk for hypertension (high blood pressure), cardiovascular disease, stroke, cancer, gallbladder disease and diabetes. Obese patients can have higher levels of cholesterol and lipids circulating in their bloodstreams. This can lead to the buildup of atherosclerotic plaques in blood vessels, which increases the risks of high blood pressure, heart attack and stroke. So, obesity is a well-known risk factor for developing cardiovascular disease.
Next, we'll learn how scientists discovered the obesity paradox.
Obesity Paradox Research
In 2001, A. Mosterd and colleagues from the Netherlands studied the prognosis of patients diagnosed with heart failure. They did statistical analyses on more than 5,000 patients, some of whom had heart failure. They found that patients with low BMIs and low blood pressure had more in-hospital deaths than patients with higher BMIs. The researchers claimed that their
discoveries supported similar findings from a 1993 study in Massachusetts, and since 2001, at least eight studies have supported the findings. So, even though obesity is a well-known risk factor for heart failure and would be expected to cause problems for obese heart-failure patients, it seems that the opposite could be true.
The obesity paradox extends to other conditions besides heart failure. Patients with chronic kidney disease most often undergo hemodialysis, where a machine filters impurities out of the blood, and dialysis. About 20 percent of dialysis patients die each year from cardiovascular complications. Studies by researchers at UCLA Medical Center have shown that dialysis patients with higher BMIs have a better chance of survival than those with lower BMIs.
To summarize, the obesity paradox goes something like this. Obesity is a major risk factor for cardiovascular disease (like hypertension, congestive heart failure, coronary artery disease) and chronic renal disease. However, in patients with these chronic diseases, it appears that obesity is associated with better survival. If this finding is actually true, it could have important implications for how physicians treat patients with chronic diseases. Doctors could conceivably stop putting patients on diets and recommending that they lose weight.
So, why does the obesity paradox happen? We'll find next..
Obesity Paradox Explanations
The medical community has had mixed reactions to the idea of the obesity paradox. Many physicians and scientists are skeptical because the findings go against what is expected from the normal population. Researchers at the University of Texas School of Public Health and Baylor Medical College reviewed many published reports of the obesity paradox and came up with six reasons to explain the findings -- and possibly to be skeptical of them [source: Habbu].
- The numbers of people studied in the reports of the obesity paradox were generally small. Therefore, do these results apply or hold in much larger populations?
- The statistical techniques show associations between factors, but not cause-and-effect conclusions. So, the results may or may not be real.
- In many studies, congestive heart failure was diagnosed from clinical symptoms (difficulty breathing, swelling in extremities) instead of from laboratory tests (like echocardiography, cardiopulmonary testing, cardiac catheterization).
- These clinical criteria to diagnose congestive heart failure have not been validated in obese populations and may not be applicable.
- In some of the studies where lab tests were done, the obese patients had slightly better heart functions (pumping ability, oxygen delivery) than normal or underweight patients.
- Therefore, the obese patients may have been either slightly "healthier" with respect to CHF or in earlier stages of CHF than their normal/underweight counterparts. So obese survival rates were better.
- Congestive heart failure (and chronic kidney disease) is a wasting disease. Patients are so sick that they lose weight (fat, muscle mass) over the course of the disease. This could lead to two conclusions:
- Again, obese patients could be "healthier" or in earlier stages of these chronic diseases. Chronic disease patients with low BMIs do not have low BMIs intentionally, but because of the nature of the wasting disease. None of the studies discriminated between intentional weight loss (from diet and exercise) and unintentional weight loss (from disease).
- Obese patients may have a better metabolic reserve than their normal/underweight counterparts.
- Few of the studies looked at extreme obesity (BMI more than 35). In some studies that did, the extremely obese did not have a greater chance of survival than the underweight. Therefore, the survival curves may be U-shaped. Normal and overweight patients would have better survival probabilities than those at the extremes -- underweight and extremely obese.
- Some recent studies have questioned whether BMI is the best way to categorize obesity. Maybe waist circumference or waist-to-hip circumference ratios may be better indicators of obesity. These criteria are based on observations that body fat stored in the waist is worse with respect to the risks of obesity than fat stored elsewhere.
Next we'll learn about more explanations for and criticisms of the obesity paradox theory.
Obesity Paradox Criticisms
There are many reasons to be skeptical of the obesity paradox, but the UCLA researchers have posed some biological explanations for it [source: Kalantar-Zadeh].
- The adverse effects of obesity take more time to develop than those of chronic disease (heart failure, kidney disease). Therefore, the consequences of wasting kill patients much faster than obesity does.
- In both CHF and chronic kidney disease, malnutrition and inflammation are common. These conditions alone could reduce the survival of these patients. Therefore, weight gain could be an indicator of better nutrition and, therefore, improved chances of survival in obese patients.
Dr. Kalantar-Zadeh argues that dietary restrictions placed on CHF and chronic kidney disease patients my actually be harmful to these patients. He advocates a "reverse epidemiology" approach to these conditions. So, the obesity paradox has been observed in several clinical settings (CHF, chronic kidney disease), but physicians and scientists still aren't sure that it's a real phenomenon. Not many researchers have proposed biological hypotheses to explain the obesity paradox. There have been no direct animal studies or clinical trials that could address cause-and-effect relationships. So, based on evidence available at this time, we can't conclude that the obesity paradox is real, certainly not enough to alter treatment for patients with CHF and chronic kidney disease. But many scientists think that research should be aimed at resolving the obesity paradox. It may have implications for changing treatment options for these patients.
Dr. Kalantar-Zadeh and colleagues also argue that the risk factors for the general population may not be applicable to the obese population. The obesity paradox is one example of this idea, which has been called reverse epidemiology. Imposing dietary restrictions on obese chronic disease patients, they say, may actually be harmful. The group cites a number of conditions where phenomena like the obesity paradox have been observed.
I hope now you'll take care of your health.
Posted by Nirav Ashara in How Wind-up Cell Phone Chargers Work on Monday, July 13, 2009
How Wind-up Cell Phone Chargers Work
Cell phones make communicating with each other from remote locations significantly easier. For many of us, it's comforting to know that when we head out for a drive or go traveling, we'll have the means to call anyone on our contact list. We can also use our cell phones in case of an emergency.
However, the nature of cell phones and other portable battery-powered devices means they need constant power in order to work properly. When you first get a cell phone, it seems like it'll last for weeks on just one charge. But as time goes by, the lithium-ion batteries these devices use can't hold as much charge, and they need to be recharged more often. As much as you try to keep your phone alive, chances are you'll run into a difficult situation where you'll need to use the phone but can't because of little or no available power. Cell phones fit snugly into the realm of Murphy's Law -- if it's possible for you to forget a charger and let your battery run too low, it's going to happen.
Sometimes you're in a place where there's no outlet, like in your car in the middle of a traffic jam. Maybe you've just started a weekend of camping, but the moment your arrive at the campsite you realize you only have one bar of battery life left and not much time before the cell phone becomes useless. Perhaps you've forgotten your charger or your friend offers to lend you his or her charger, which you try, only to find that doesn't fit your phone.
In any of these cases, it might help to have a source of power that doesn't rely on outlets or certain types of chargers. One helpful device that's portable and easy to use is a wind-up cell phone charger, a simple tool that requires just a little bit of elbow grease to keep your phone running. They're small and fit most phones, and most models cost between $25 and $35. Keep reading to learn more about how wind-up cell phone chargers work.
Mechanics of Wind-up Cell Phone Chargers
So what's going on inside a wind-up cell phone charger? How does the simple turning of a crank lead to extra juice for your phone's battery?
To understand the basics of wind-up cell phone chargers, it helps to look at a much bigger, yet surprisingly similar, technology -- wind turbines and wind power. When we use massive fans to generate electric power, we're relying on the motion of wind. In the simplest terms, the blades of the fans capture kinetic energy, or the energy of motion, from the movement of the wind. As the blades spin, so does the shaft that the blades are attached to. As the shaft spins, it creates rotational energy, and it transfers this energy over to a generator. A generator, in the case of a wind turbine, is simply a set of magnets that spin around a coiled wire. The magnets spinning around the wire create an electrical current, providing us with power.
A wind-up cell phone charger is like a miniature wind turbine, except instead of using wind to power a generator, your arm and hand provide the kinetic energy necessary to move the charger's crank and add battery life to your phone.
Although there are various types of designs, most wind-up cell phone chargers use a similar design and basic principles to generate sufficient power. A common element among these devices is a simple crank, a graspable lever that we can easily hold onto and turn in circles while holding the base of the charger. The crank usually has an easy-to-grip handle to make it simple to hold and spin faster. The center part of this crank is a short shaft -- remember, just like a wind turbine. The kinetic energy from your arm and hand is transferred to the shaft, which turns into rotational energy as the shaft spins. Connected to the shaft is a set of gears, which transfers that rotational energy further to the charger's generator, creating anywhere between 4 and 6 volts for your phone's battery.
Using Wind-up Cell Phone Chargers
So what do you do when your battery on your cell phone runs out and you're forced to use some muscle with your wind-up charger? Fortunately, most chargers are very small and lightweight, even smaller than most cell phones, so they're easy to carry with you and could easily store in a car's glove compartment, a purse or backpack. They typically weigh no more than a couple of ounces.
When your phone needs some extra juice, simply connect the wind-up charger to your cell phone's input. To give the phone's battery its power, you'll need to turn the crank vigorously. Most wind-up charger instructions say to crank at a rate of two revolutions per second, although turning the crank slower or faster is fine and will still provide power to the battery. Depending on the model, you can get 25-30 minutes of extra standby power to a cell phone after just a few minutes of solid cranking. You should only be able to get about 6 minutes of call time from the same amount of exercise, however, since it requires more power to send out signals.
If you have a hands free set like a Bluetooth earpiece, you can even hold the charger and talk at the same time, since charging is a two-handed operation. As long as you keep turning the handle, the power you provide to charge the phone should be greater than the power needed to keep the phone on. This allows you to talk and provide a charge continuously.
What about the different types of inputs on cell phones? Often one of the more frustrating things about losing battery power on your cell phone is when someone else actually has a charger available, but the parts don't fit. Fortunately, many wind-up cell phone chargers come with adapters that fit most phones so you should be able to find the right charge input.
And if the potential to create battery power without the use of an outlet wasn't enough, some models, such as the Sidewinder, even have a built-in LED light that will work after a few seconds of cranking. This feature could be helpful in the event you've lost your phone and there's no other available illumination.