- 2008
- Dec
- 28
Fire Door
A fire door is a type of door, or barrier used as a passive fire protection item within buildings to prevent the spread of fire or smoke which may consist of dangerous chemicals. It is usually the only means of allowing people to pass through a fire-resistance rated wall assembly.
Fire doors are made of a combination of materials, such as:
* timber
* steel
* gypsum (as an endothermic fill)
* vermiculite-boards
Apart from the door leaf (the swinging panel of the door) there is the door frame which also has to meet fire rated regulations, intumescent strips, smoke seals, door hardware and the structure that holds the fire door assembly in place. Together, these components form an assembly, typically called a “doorset” which holds an hourly rating.
All of the components of the fire door assembly must bear a listing agencies label to ensure the components have been tested to meet the fire rating requirements.
Door Hardware
Door hardware includes, but is not limited to:
manual or automatic closing devices
* locks
* latches
* hinges
* door sweeps
* thresholds
Edges of a fire door usually need to have fire rated seals which can be composed of:
* An intumescent strip, which expands when exposed to heat
* Neoprene weatherstripping
* Smoke gasketing to prevent the passage of smoke
Intumescent seals are crucial in the fire performance of a fire resisting door set and as such the correct seal should always be used as these products differ in chemical composition, expansion rate, expansion volume and charring characteristics.
Some fire doors are equipped with internal windows which also have a rating, or have been incorporated at the time of the door test and be subject to the overall door’s product certification. Fire-resistive windows must remain intact under fire conditions and hose stream impact resistance, and can include:
* wire mesh glass
* liquid sodium silicate fills between two window panes
* ceramic glasses
* borosilicate glass
Wired glass typically withstands the fire, whereas the sodium silicate liquid also acts to insulate heat transfer, due to the endothermic action of this chemical.
Combustibility
Fire doors are not necessarily all noncombustible. A fire door is but one of many passive fire protection components used to compartmentalise fire and thus keep it in the compartment of origin, so either it runs out of fuel or it is extinguished, or, at the very least, enough time has been bought to enable evacuation of the building.
Fire door failure
Fire doors are sometimes rendered unable to provide its listed fire resistance by ignorance of the intended use and associated restrictions and requirements, or by inappropriate use. For example, fire doors are sometimes blocked open, or carpets are run through them, which would allow the fire to travel past the fire barrier in which the door is placed. The door’s certification markings are displayed both on the door leaves and the fire door frames, and should not be removed or painted over. Such neglect is the responsibility of the building owner, who should educate occupants on the safe use of all safety related items, to ensure fire safety and compliance with the fire code.
Sometimes fire doors have apparently very large gaps at the foot of them, an inch or two even, allowing air movement, especially in dormitory facilities. This can lead the occupants of a building to question their status as ‘real’ fire doors. Testing of fire doors include a maximum door undercut of 3/4 inch. Corridors have a fire rating of one hour or less, and the fire doors in them are required by code to have a fire rating of 1/2 or 1/3 hr, the intent of which is mainly to restrict smoke travel.
Normal operation
Most fire doors should be kept closed at all times, however some are designed to stay open under normal circumstances, only to shut automatically or manually in the event of a fire. Whichever method is used, the door’s movement should never be impaired by a doorstop or other obstacle. Proper intumescent and smoke-seal bounding of fire doors should be routinely checked and ensured, as should the action of the door closer and latch.
Some fire doors are held open with an electromagnetic coil, which may be wired to a fire alarm system via relays. If the power fails or the fire alarm is activated, the power to the coil is cut and the door closes on its own.
Rated fire doors are tested to withstand a fire for a specified period. There are 20, 30, 45, 60 and 90-minute-rated fire doors that are certified by an approved laboratory (e.g. Underwriters Laboratories). The certification only applies if all parts of the installation are correctly specified and installed. For example, fitting the wrong kind of glazing may severely reduce the door’s fire resistance period.
Construction and Installation issues
As well as ensuring the door is hung properly and squarely, it is also very important that where a fire door is installed, any gaps left in the opening between the wall and the door frame must be properly filled with fire resisting material.
Architect’s responsibility
In building design drawings with poor identification of which walls do in fact have a fire-resistance rating, it is often necessary to check the door schedule in the specifications to be able to trace what walls are rated and how long they are rated for. This is an indicative sign about the architect and the degree of care taken particularly with items relating to passive fire protection. To avoid confusion about any fire protection measures including fire doors, it is best for the architect to provide a separate set of drawings that clearly outlines which walls and floor have a fire-resistance rating and exactly what that rating is. It is also important to point out especially which walls are firewalls and which walls and/or floors are designated as occupancy separations, as the nature of passive fire protection devices that must be used in those special cases can be substantially different from such devices that are used in ordinary fire separations.
- 2008
- Dec
- 27
buy.com
Buy.com is an online retailer based in Aliso Viejo, California. It began by selling computers and electronics in 1997 and has since expanded into many other categories. Initially the company sold items below cost and intended to make up the losses from the sale of advertising and ancillary services like warranties and equipment leases. Buy.com sold $111 million worth of goods and services in 1998, its first full year, beating Compaq’s record for most first-year sales of any company.
Founder Scott Blum sold his stake to SoftBank in 1999 for $195 million just before the company first filed to go public. Stock values plummeted in the year following Buy.com’s initial public offering and in 2001 Blum reacquired Buy.com and took it private for 17 cents per share.
What got my attention was some of the witty youtube videos floating around promoting buy.com.. They are hilarious.. You are sure to buy something if you see the ads..
- 2008
- Dec
- 20
A Hyderabad Trip?
Looks like I may have to go to Hyderabad for a few days.. Business of course.. But I do hope there is scope for pleasure..
- 2008
- Dec
- 14
How Diet Pills Work
by Stephanie Watson (howstuffworks.com)
Their ads claim they can help you “feel more fit,” “boost your energy” and “melt away the pounds.” Who needs diet and exercise when a little pill can erase the weight quickly and easily? With more than 60 percent of Americans now considered overweight or obese, diet drugs have turned into a multibillion dollar industry in the United States.
But although diet pills promise a quick fix, can they deliver? Can they help you lose weight? And if so, can they help you keep it off? Weight-loss questions aside, several diet drugs over the last decade have been associated with serious heart problems and other health-related issues, and diet pills have even been linked to a number of deaths.
In this article, we will look at the wide variety of diet pills available, find out how they work and what their side effects are and see if they live up to their promises.
Diet Pill Varieties
Diet drugs are available in several different forms, including prescription drugs, over-the-counter drugs and herbal supplements.
Prescription drugs such as Meridia and Xenical are only available with a doctor’s prescription. They are carefully regulated by the Food and Drug Administration (FDA) Center for Drug Evaluation and Research, and their use is closely monitored by the prescribing doctor.
Over-the-counter drugs are available without a doctor’s prescription, right in your local drugstore or supermarket, and are also regulated by the FDA. According to AnneCollins.com, “Products considered by FDA to be over-the-counter weight control drugs [as opposed to dietary supplements] are primarily those containing the active ingredient phenylpropanolamine (PPA).” In 2000, the FDA requested that drug manufacturers voluntary reformulate PPA-containing products in the wake of evidence that phenylpropanolamine can increase the risk of stroke, so there are few diet drugs on the market that still contain this ingredient. OTC drugs also fall under the jurisdiction of the FDA’s Center for Drug Evaluation and Research.
Herbal diet supplements are also available without a prescription. You’ll typically find a huge variety of these in health food and nutrition stores as well as in regular supermarkets. Herbal supplements are often labeled “all natural” and are considered by the FDA to be food products as opposed to drugs. As such, they fall under the jurisdiction of the FDA’s Center for Food Safety and Applied Nutrition and are regulated differently from OTC drugs.
There is also a selection of diet aids that are administered by patch, as a powder or in liquid form. These types of drugs may fall into any of the above categories — it is only the delivery method that is unique.
Prescription Diet Pills
Different diet pills work in different ways depending on which ingredients they contain.
Appetite suppressants such as sibutramine (Meridia), diethylpropion (Tenuate) and phentermine (Adipex-P, Fastin, Anoxine-AM, etc.) affect the appetite-regulating region of the brain called the hypothalamus. They work by blocking the re-uptake of the chemicals serotonin and norepinephrine, which create that feeling of satiety you get after eating a big meal. With more of these chemicals circulating in your brain, you feel full, so you eat less.
Prescription fat blockers, such as orlistat (Xenical), inhibit the action of an enzyme called lipase. When we eat foods with fat in them, lipase normally breaks down the fat when it gets to the intestinal tract. With a lipase inhibitor in effect, a percentage of the fat ingested is removed from the body through bowel movements instead of being broken down and absorbed.
Many prescription drugs are used as diet aids even though that was not their intended purpose. Some antidepressants are used “off-label” as diet aids because they have been shown in studies to help patients lose weight and keep it off for several months. Researchers are also studying certain drugs normally used to treat epilepsy (topiramate and zonisamide) and diabetes (metformin) for their weight-loss potential.
Because diet pills are such a lucrative business, pharmaceutical companies are pushing to introduce more products to the market. More than 100 new weight-loss medications are either in development or in clinical trials as of January 2005. One of the most promising is rimonabant (Acomplia), which acts on a protein in the brain called the endocannabinoids. Endocannabinoids are similar in structure to the active ingredient in cannabis (marijuana) and may be responsible for appetite control. Rimonabant blocks the endocannabinoids from reaching their receptors in the brain. By blocking this protein, the drug reduces food cravings. In clinical trials, one-third of obese people who were given Acomplia lost more than 10 percent of their body weight and were able to keep it off for up to two years. The drug also has a few welcome side effects: It increases HDLs (”good cholesterol”) while lowering triglycerides (a form of fat that is carried in the bloodstream). Acomplia may even help smokers kick the habit.
Other promising drugs affect appetite-related hormones. One blocks ghrelin, which the stomach sends to the brain to increase appetite. Another mimics a hormone called PYY, which tells the body it’s full.
Who Should Use Prescription Diet Pills?
Prescription diet pills aren’t for the person who wants to shed a few pounds to fit into a holiday party dress or tuxedo. Only people who are “obese” (those who are 30 percent over their ideal weight, or have a Body Mass Index (BMI) of 30 or more - or who have a history of high blood pressure or diabetes are good candidates for prescription diet medications, according to the National Institutes of Health (NIH).
Even though approximately 16 percent of American children are overweight, most diet pills are not recommended for use by children under the age of 16. The exception is orlistat, which can safely be used by teens 12 and older.
If you watch late-night TV, you know that it seems like every other ad is touting the miraculous claims of the latest over-the-counter diet pill.
OTC Diet Pills
Some over-the-counter pills (such as Xenedrine, Dexatrim and Zantrex-3) once used a powerful combination of the stimulant ephedra and caffeine to help users shed pounds. They reportedly worked in combination by increasing energy expenditure — or thermogenesis (it is thought that caffeine increases metabolism by increasing the breakdown of fatty acids) — and reducing appetite (ephedrine acts on the satiety center in the hypothalamus). But since late 2003, when the FDA banned the sale of ephedra-containing drugs due to evidence of increased risk of heart attack, these formulations have replaced ephedra with a mixture of vitamins (such as thiamin, riboflavin, vitamin B-6, folic acid), an ephedra-like substance called synephrine that is found in certain citrus fruits, and caffeine. The combination reportedly increases energy while boosting metabolism.
There are many herbal weight-loss supplements on the market today, and they utilize different mechanisms to reportedly aid in dieting. Here are some of the more common ingredients and their reported weight-loss mechanisms:
* Herbal ephedra, caffeine, guarana and country mallow - Increase metabolism
* Guar gum, glucomannan and psyllium - Cause a “full” feeling
* Hydrocitric acid, green tea, conjugated linoleic acid and pyruvate - Slow fat production
* Chitosan (or chitin - substance found in the exoskeleton of shrimp and other shellfish) - Block fat from being absorbed
So as you can see, there are a lot of diet pills out there, all claiming to help you lose weight in one way or another. But do they really work? And what kinds of side effects can you expect?
Do Diet Pills Really Work?
Many over-the-counter diet pill manufacturers say their product will help you see miraculous weight loss — like losing up to 30 pounds in 30 days — without diet or exercise. Their claims sound too good to be true, and most of them are.
A few pills, especially the newer prescription varieties (such as Meridia and Xenical), have been shown in clinical studies to help dieters shed a few pounds. But the majority of the ads you see on the Internet and TV are for products that are unregulated, untested and unproven.
Even the most effective diet pills are only meant to be taken for a short period of time — usually six months or less. During that time, doctor-prescribed weight-loss drugs can trim anywhere from 5 to 22 pounds, or up to 10 percent of your body weight. But after six months, your body develops a tolerance to these drugs’ effects, and weight loss plateaus. After that, if you don’t also follow a healthy eating and exercise plan, the weight will come right back.
Side Effects of Diet-pill Use
Different diet pills contain different ingredients, so their side effects vary:
As fat blockers like orlistat (Xenical) remove excess fats via the intestines, they may cause uncomfortable cramping, gas and diarrhea. Because these drugs also reduce the body’s absorption of essential vitamins and nutrients, people who take Xenical are advised to take a daily multivitamin supplement.
Sibutramine (Meridia) and other similar appetite suppressants stimulate the sympathetic nervous system, which can raise blood pressure and heart rate. This increases the risk of heart attack and cardiac arrest, especially among people who already suffer from high blood pressure, irregular heartbeat or heart disease. In fact, between February 1998 and March 2003, the FDA received reports of 49 deaths related to sibutramine. Other, more minor side effects include constipation, headache, dry mouth and insomnia (because the chemicals in these drugs also influence sleep patterns).
Herbal diet pills, even though they’re “all natural,” can have potentially dangerous side effects depending upon their ingredients. “Herbal” doesn’t necessarily mean “safe.” Also, because they are considered part of the food industry and are therefore regulated differently by the FDA, there is no guarantee that they can live up to their manufacturers’ claims.
Dangerous Diet Pills
In the mid-’90s, the diet pill industry was booming. In 1996, more than 18 million dieters in the United States were taking a cocktail of the appetite suppressants fenfluramine (or dexfenfluramine) and phentermine, nicknamed fen-phen — many with great success. But suddenly, doctors around the country were seeing previously healthy patients who were taking fen-phen developing a potentially fatal heart disease. In September 1997, the FDA announced that it was withdrawing the “fen” drugs from the market because of their link to heart problems. Phentermine is still available on its own.
Another popular diet pill ingredient in the ’90s was a powerful amphetamine-like stimulant called ephedra (or the Chinese herb ma huang), which, in combination with caffeine, triggered measurable weight loss. The problem was, because it sped the heart rate, ephedra also dramatically increased the risk of heart attack and stroke. Ephedra is related to epinephrine (adrenaline), which, during times of stress, constricts blood vessels, elevates heart rate and gets the body ready to fight or flee. At least 155 people died from taking medications containing ephedra. In late 2003, the FDA announced that it would ban the sale of all ephedra-containing drugs. In response, manufacturers of over-the-counter diet pills such as Dexatrim, Metabolife and AcuTrim began removing the ingredient from their products and now produce ephedra-free versions.
- 2008
- Dec
- 14
Top Fat Burners
The following is an extract from bodybuilding.com written by doggiejoe.
Oh ephedra, ephedra, where is my ephedra? It’s been well over a year since you were able to purchase ephedra legally over the counter. The loss was a huge one and nearly took out the heart of the supplement world. But we got through it. Yes, ladies and gentleman, we got through it. Later on in this article you’ll see the products that helped us get over the loss of ephedra.
Without the benefit of ephedra, supplement companies were left with no option but to create new fat burning products. The initial fat burners that came out after the ban weren’t that great to say the least. The leading brands Xenadrine and Hydroxycut from the ephedra era produced some disappointing post-ephedra supplements. They had everyone believing that their post ephedra products were going to be just as good or better than the original. Boy, were we fooled.
That led everyone to believe that without ephedra there wouldn’t be another best fat burner that actually worked. But with the loss of ephedra, it also brought about new exciting ingredients to light.
Here are some of the ingredients that came to light:
Green Tea Extract
Green tea came from China, and is said to have been used for thousands of years. It was never really regarded as a fat loss agent until ephedra was banned. Green tea is a very versatile ingredient that can be used by the body in many different ways.
It also works as an anti-inflammatory. What has been overlooked is its effectiveness in also reducing fat in your body. It is a great ingredient to cut down on fat and is even better for your overall health. It is also good at giving you energy throughout the day, so you can replace your regular coffee with green tea.
R-ALA
R-ALA is the purest form of ALA (Alpha-Lipoic-Acid). What it does, is that it speeds the removal of sugar from the blood. It’s quickly turning into a widely used fat loss ingredient.
It also works for energy because it helps break down sugar for the production of ATP, which helps your body go. This helps carbs be used as energy and not be stored as fat. It even works as an anti-aging product and it is also proven to expand your total lifespan.
CLA
Basically CLA is a fatty acid that in turn helps you lose fat. It is naturally occurring and can be found in meat and diary products. Not only will CLA help you naturally burn off fat, but it will also build muscle. CLA is also proven to improve your food intake efficiency. Not only can CLA make you lose fat, but also once you dropped the amount of weight you desire it will help you maintain that weight. In some studies it shows to even improve concentration and sleep.