Jun 28, 2014

Alternative technologies concerning energy

What makes a technology conventional is its widespread use, and what makes it widespread is its low cost and convenience. Therefore, almost by definition, alternative technologies cost more than conventional ones, at least in terms of the price paid by the consumer. For example, among alternative technologies, wind power has come the closest to competing with conventional fossil fuels, yet it still costs about 50 percent more than coal-generated electricity. If, however, one takes into account the hidden costs of conventional energy and the noneconomic benefits of alternative technologies, then the equation changes.

Growing awareness of the environmental costs of conventional energy has led to increased demand for cleaner energy. Global warming, in particular, has altered the way many people think about the energy they consume - which, in turn, has begun to reshape the economic relationship between energy producers and consumers. As more and more consumers sign up for green energy programs and buy hybrid cars (both of which carry additional costs), energy companies are reconsidering whether the conventional wisdom of cheap, convenient, and plentiful above all still applies. Skeptics argue that the demand for cheap, large-scale energy resources will continue to trump the relatively new consumer preference for clean, renewable alternatives. On the other hand, if the era of cheap petroleum-based energy is indeed ending -- as shrinking petroleum reserves and rising gasoline prices indicate -- then one may not even have to factor in the hidden costs and benefits for today's alternative technologies to become tomorrow's conventional resources.

Jun 21, 2014

Slide Rule

A mechanical device formerly used by engineers and scientists for rapid and approximate multiplication, division, extraction of roots, raising to powers, and other simple computations. The slide rule has been almost totally superseded by the small hand-held electronic calculator. The principle of the slide rule is the translation of all computations to equivalent additions or subtractions that can be carried out on a set of scales sliding over each other. Thus, two uniformly graduated marked scales can be used for addition or subtraction, multiplication, division, powers, and logarithms. Other scales, such as for sine, cosine, and tangent, and logarithm and for calculations involving p (pi) are also found on the usual rectilinear slide rule. A glass runner or cursor with a finely engraved vertical line is provided for easier alignment of the scales.

The computational accuracy possible depends on the size of the slide rule and on the care with which the scales are printed. The commonly used 10-in. slide rule permits multiplications and divisions to be made with an accuracy of about 1/10th percent, which suffices for many engineering calculations. Both the rectilinear and the less commonly used circular slide rule were invented by the English mathematician William Oughtred shortly after the discovery of logarithms. Various special slide rules have been devised for the solution of widely applicable engineering formulas, or for business calculations, such as the determination of interest, compound interest accumulation, and depreciation. 
(Adapted from Encarta Encyclopedia)

Jun 14, 2014

Renewable Energy – wind and solar

The first wind turbines actually predate the electric power grid, with two near-simultaneous developments in the late 19th century. The Scottish engineer James Blyth constructed a 33- foot electricity-generating wind turbine in 1887, and the following year the American engineer Charles Brush built the first automatic wind turbine, wiring the first electrically powered building in Ohio. Likewise, throughout the 1800s, scientists were experimenting in the various technologies that make photovoltaic solar panels possible; the first solar powered steam engine was built in 1861.

Since then, the use of wind and solar power has grown steadily, with a surge in recent years. Wind power, while, still providing a small total percentage of U.S. power, is growing much more rapidly than solar power. From 1990 to 2008, U.S. production of wind power grew from 300 trillion Btu annually to 510 trillion; solar has increased modestly from 60 trillion BN to 90 trillion. Shipments of solar photovoltaic cells and modules continues to expand, however. From 2000 to 2008, U.S. manufacturers increased shipments of photovoltaic components from 20,000 modules in 2000 to 524,000 modules in 2008. Production of hydroelectric power, the nation's largest renewable energy source, has remained more or less steady since 1990, declining somewhat from 3.05 quadrillion Btu to 2.45 quadrillion Btu in 2008.

Jun 7, 2014

Environmentalism in the United States

The first federal environmental act was the establishment of Yellowstone National Park in March 1872 in the territories of Montana and Wyoming. Instead of promoting the land for development, Congress and President Ulysses S. Grant declared that it should be preserved "as a public park or pleasuring ground for the benefit and enjoyment of the people." As the first such preserve in the world, Yellowstone inaugurated an international national park movement that currently includes some 1,200 parks or preserves in 100 countries, including 391 in the United States.

The Scottish naturalist John Muir became an early advocate for preservation after his travels and scientific work convinced him that some natural areas need protection from human exploitation. Muir founded the Sierra Club in 1892 to that end and urged President Theodore Roosevelt to join the cause. Roosevelt, himself known as an ardent outdoorsman, eventually dedicated more than 150 million acres to national parks and forests, and founded the US. Forest Service, which manages forests for water and timber resources while protecting them for wildlife and recreation. The first chief of the Forest Service, Gifford Pinchot, promoted a "wise use" strategy of wilderness management that proposed, in contrast to Muir, that nature could be safely commercialized.