Tag: Power

What Is A Horsepower?

The horsepower (hp) is a unit in the foot-pound-second ( fps ) or English system, sometimes used to express the rate at which mechanical energy is expended.

It was originally defined as 550 foot-pounds per second (ft-lb/s).




A power level of 1 hp is approximately equivalent to 746 watt s (W) or 0.746 kilowatt s (kW). To convert from horsepower to watts, multiply by 746.

To convert from watts to horsepower, multiply by 0.00134. To convert from horsepower to kilowatts, multiply by 0.746. To convert from kilowatts to horsepower, multiply by 1.34.

While the horsepower, the watt, and the kilowatt are all reducible to the same dimensional units, the horsepower is rarely used to express power in any form other than mechanical.

You will likely get raised eyebrows if you talk about a 1-hp microwave oven, just as you would feel uncomfortable talking about a 37-kW outboard motor.

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Pass it on: Popular Science

Why Is Power Consumption For Gadgets Dropping At Home?

A new report from the Consumer Electronics Association and Fraunhofer USA asserts that the power consumed by home electronics declined from 12% between 2013 and 2010 in the U.S.

It’s a positive result, especially when you add in that the number of devices climbed from 2.9 billion to 3.8 billion over that same period.

But what’s really interesting about the report is why power consumption is declining.




In a word, it’s tablets. The number of plugged in TVs has declined from 353 million in 2010 to 301 in 2013, a 14% drop.

The number of plugged-in desktops has dropped from 101 million to 88 million while the number of active laptops has declined from 132 million to 93 million.

Tablets, meanwhile, have gone from being a relative asterisk to being present in 100 million households.

While part of the decline in consumed by TVs can be attributed to new accounting methods and the final disposal of those remaining CRT tubes, the bigger impact seems to be coming from the shift to smaller screens.

The active power consumption of a 34-inch TV is 90 watts: a TV this size will consume 166 kilowatt hours a year under normal use scenarios. Desktops will consume 186 kilowatt hours.

Notebook power draw can range from 6 to 36 watts and account for 53 kilowatt hours of power consumption. A tablet might use 6.1 kilowatt hours a year in regular use.

In short, power consumption is dropping at home, but more importantly we are seeing a tectonic shift in what we use.

Tablet sales might be below some analyst’s expectations, but they are having an impact on the categories around them.

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Pass it on: Popular Science

How Do Fireflies Glow? Mystery Solved After 60 Years

Think of the firefly abdomen like a black box of bioluminescence.

For around 60 years, scientists have known what basic ingredients go into the box—things like oxygen, calcium, magnesium, and a naturally occurring chemical called luciferin.

And they’ve known what comes out of the box—photons, or light, in the form of the yellow, green, orange, and even blue flickers you see dancing across your backyard on summer nights.




But until recently, the actual chemical reactions that produce the firefly’s light have been shrouded in mystery.

And scientists like Bruce Branchini at Connecticut College love a good mystery.

The way enzymes and proteins can convert chemical energy into light is a very basic phenomenon,” he says, “and we wanted to know how that biochemical process worked.”

In new research, Branchini and his colleagues did just that: They found an extra oxygen electron that’s responsible for the beetles’ summertime glow.

The discovery, published recently in the Journal of the American Chemical Society, provides the most detailed picture yet of the chemistry involved in firefly bioluminescence.

The conventional explanation of how a firefly turns its backside into a bioluminescent beacon has always troubled Branchini and other chemists. For starters, it shouldn’t work.

Specifically, two of the ingredients mentioned above—oxygen and luciferin—aren’t likely to react to each other in the way they would need to in order to produce light.

Understanding why this is gets complicated fast, but a simple explanation is that apples tend to only create chemical reactions with apples, while oranges tend to only create chemical reactions with oranges.

In other words, oxygen and luciferin are like apples and oranges.

Branchini’s experiments showed the oxygen involved in the firefly’s glow comes in a special form called a superoxide anion.

This extra electron gives the oxygen properties of both a metaphorical apple and a metaphorical orange.

This means that the molecule would, in fact, be able to cause a chemical reaction with the luciferin like scientists have suspected.

He adds that these superoxide anions could be the way bioluminescence works across nature, from plankton to deep-sea fish.

To me, chemically, this is the only way it makes sense,” says Stephen Miller, a chemical biologist at the University of Massachusetts Medical School who also studies luciferin and its potential uses for human health.

Miller, who was unaffiliated with the study, says it’s important to keep studying luciferin and bioluminescence because of their potential applications for medicine.

For instance, earlier this year, Miller was part of a team that used luciferin to detect specific enzymes in the brains of living rats, which could someday offer doctors another window into the human brain.

Firefly luciferin is already proving to be a useful tool in imaging human tumors and developing cancer-fighting drugs, says lead author Branchini.

Ultimately, though, “we just want to know how nature works,” he says. “The applications may or may not follow.

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Pass it on: Popular Science

Hydrogen Energy And Fuel Cell Technology

hydrogen

Hydrogen is the simplest element. An atom of hydrogen consists of only one proton and one electron. It’s also the most plentiful element in the universe.

Despite its simplicity and abundance, hydrogen doesn’t occur naturally as a gas on the Earth – it’s always combined with other elements. Water, for example, is a combination of hydrogen and oxygen (H2O).

Hydrogen is also found in many organic compounds, notably the hydrocarbons that make up many of our fuels, such as gasoline, natural gas, methanol, and propane.




Hydrogen can be separated from hydrocarbons through the application of heat – a process known as reforming. Currently, most hydrogen is made this way from natural gas.

An electrical current can also be used to separate water into its components of oxygen and hydrogen. This process is known as electrolysis.

Some algae and bacteria, using sunlight as their energy source, even give off hydrogen under certain conditions.

Hydrogen is high in energy, yet an engine that burns pure hydrogen produces almost no pollution. NASA has used liquid hydrogen since the 1970s to propel the space shuttle and other rockets into orbit.

h20

Hydrogen fuel cells power the shuttle’s electrical systems, producing a clean byproduct – pure water, which the crew drinks.

A fuel cell combines hydrogen and oxygen to produce electricity, heat, and water. Fuel cells are often compared to batteries.

Both convert the energy produced by a chemical reaction into usable electric power. However, the fuel cell will produce electricity as long as fuel (hydrogen) is supplied, never losing its charge.

Fuel cells are a promising technology for use as a source of heat and electricity for buildings, and as an electrical power source for electric motors propelling vehicles.

Fuel cells operate best on pure hydrogen. But fuels like natural gas, methanol, or even gasoline can be reformed to produce the hydrogen required for fuel cells.

Some fuel cells even can be fueled directly with methanol, without using a reformer.

In the future, hydrogen could also join electricity as an important energy carrier. An energy carrier moves and delivers energy in a usable form to consumers.

Renewable energy sources, like the sun and wind, can’t produce energy all the time. But they could, for example, produce electric energy and hydrogen, which can be stored until it’s needed.

Hydrogen can also be transported (like electricity) to locations where it is needed.

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Pass it on: New Scientist