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Thursday, July 30, 2020

HOW TO CALCULATE TIRE TURNS PER MILE - The diameter of a tire is the distance across the tire through the center. Since tires are circular, you can find the circumference of the tire from the diameter. The circumference represents the distance the tire travels when it makes one revolution. If you know the number of inches in a mile and the circumference, you can find the number of times the wheel turns per mile. First, measure the diameter of the tire in inches. Secondly, multiply the diameter by pi, which is approximately 3.1416, to find the tire circumference. For example, if the tire has a 20 inch diameter, multiply 20 by 3.1416 to get 62.83 inches. Finally, divide 63,360 inches per mile by the tire circumference to find the revolutions per mile. Finishing the example, you would divide 63,360 by 62.83 to get 1,008.44 revolutions per mile.

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Wednesday, July 29, 2020

AIR CONDITIONING MAY BE SPREADING COVID - As COVID-19 cases rise rapidly some scientists believe there could be an important, but overlooked factor in the spread of the virus in the region -- air conditioning. Just as chilly winter temps create the perfect conditions for passing colds and flu — driving people indoors and into closer proximity for more hours of the day where it’s easy to swap germs, researchers believe broiling heat in the southern U.S. could be having the same effect, sending people indoors where whirring air conditioners are running full blast. Air conditioning is also risky because of the way air handlers work. When outdoor temperatures are extreme, HVAC systems adjust the mix of fresh air they pull in to save energy. That means the hotter it is outside, the more indoor air recirculates, which means, you’re breathing a higher percentage of the same air that other people are exhaling. If someone in the building is shedding the new coronavirus, it can build up in the recirculated air. And this may seem obvious, but air conditioners have fans that blow the air around. That gives the smallest viral particles — aerosols -- extra lift to stay suspended in the air. The air currents that are produced by air conditioners and also fans and other air moving devices can carry particles further than they might otherwise go. Air conditioners also remove moisture from the air, and we know viruses prefer dry air.

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Tuesday, July 28, 2020

ROAD CRACKS - The common causes of pavement deterioration and degradation are overloading, seepage, improper or poor road surface drainage, lack of proper road maintenance, lack of proper design, adverse climatic conditions and some other factors. Road distresses disturb and adversely affect the traffic flow and traffic safety leading to poor performance of the road. They also cause an increase in fuel costs, result in time delay and prove troublesome for every road user. Identification of the road cracks at an early stage is essential as preventive road maintenance and effective remedial measures can be applied before the problem becomes too severe and the pavement fails. Pavement maintenance thus leads to enormous economic benefits in preventing the pavement from failing. Also, the distresses whether of a smaller or larger scale are a nuisance to the road users and may prove hazardous if neglected for a long period as their condition worsens with time. Proper, timely and selective road maintenance thus becomes an important principle which lengthens the life of the pavement and also reduces the cost of maintenance. Fatigue cracks are interconnected cracks that are caused under the influence of repeated traffic loading. Roads that face extreme climates and heavily loaded vehicles undergo severe fatigue cracking. It is also referred to as Alligator cracking as the crack pattern resembles the skin of an alligator.

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AIR POLLUTION - The term "air pollution" is used so commonly that you may not think definitions are necessary. Some sources define smog as the presence of unnatural levels of ground-level ozone, while other sources say things like "fog mixed with smoke." A more modern and precise definition is "a photochemical haze caused by the action of solar ultraviolet radiation on atmosphere polluted with hydrocarbons and oxides of nitrogen especially from automobile exhaust." Officially, air pollution can be defined as the presence of harmful substances in the air, either particulates or microscopic biologic molecules, that pose health hazards to living organisms, such as people, animals or plants. Air pollution comes in many forms and may include a number of different pollutants and toxins in various combinations. Air pollution is far more than a nuisance or inconvenience. Air pollution causes the deaths of approximately 4.2 million people annually worldwide. The two most widespread types of air pollution are the ozone and particle pollution (soot), but air pollution also may include serious pollutants such as carbon monoxide, lead, nitrogen oxides, and sulfur dioxide, volatile organic compounds (VOCs) and toxins such as mercury, arsenic, benzene, formaldehyde, and acid gases. Most of these pollutants are man-made, but some air pollution is due to natural causes, such as ash from volcanic eruptions.

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