BEIJING Cheap Nike Air Max 90 KPU White , May 13 (Xinhuanet) – "Images" of the sound of thunder was recently captured by scientists using an array of microphones and an especially-made rocket.

A small rocket trailing a grounded copper wire is launched into thunderclouds, creating a conductive channel for lightning to travel down. This allows the researchers to focus their instruments and perform repeated experiments.

An array of 15 microphones, each spaced one meter apart, was then placed 95 meters from the rocket launch pad.

By transforming the data captured by the microphone array of artificially-generated lightning into pictures, scientists at the Southwest Research Institute (SwRI) in San Antonio Cheap Nike Air Max 90 Leather Women's White , Texas, were able to "see" the thunder.

"The initial constructed images looked like a colorful piece of modern art," said Maher A. Dayeh, one of the researchers.

However, at higher frequencies Cheap Nike Air Max 90 Women's Black , as the sound cleaned up, they revealed a distinct thunder signature.

By the visual representation of thunder, scientists are able to help people better understand how lightning produces thunder, as well as how lightning discharges energy.

Shaping of lightening

Lightning first takes shape in clouds. As ice particles within the cloud collide and break apart, different size particles acquire different charges. The small Cheap Men's Nike Air Max 90 PRM Black , positively charged particles get pushed to the top of the cloud by updrafts of wind, while the large, negatively charged particles fall to the bottom of the cloud.

This creates a huge electric potential within the cloud, which in turn builds up an electrical energy between the cloud and the ground. The latter causes negative charges to surge up from the ground to the cloud in a flash of lightning.

At that moment in time, the surrounding air is heated to a temperature that's three times hotter than the surface of the sun. This causes the air to expand immensely Cheap Men's Nike Air Max 90 Hyperfuse Black , sending a shockwave — thunder — rippling through the air.

Thunder formation

It is this lightning that causes the sound of thunder, a sort of sonic boom caused by the thermal expansion of plasma in the lightning channel. The increase in pressure and temperature causes the air around the lightning to expand at a rate faster than the speed of sound, causing a shockwave which extends about 10 metres (30 feet) around the lightning.

After that distance, it slows enough to become ordinary sound. In close proximity, thunder is as loud as standing in front of speakers at a rock concert Cheap Men's Nike Air Max 90 Hyperfuse Premium Black White , or standing within 60 metres of a jet engine during takeoff -- 120 decibels, loud enough to cause permanent hearing loss, while the shockwave can cause property damage.

(Agencies)

by Kimathi Kamau

NAIROBI, Nov. 8 (Xinhua) -- Mary Keitany, Kenya's two-time London winner is still basking in the glow of her resolute New York conquest last Sunday that served both as a moving personal triumph on her comeback.

The New York victory saved face for elite marathon running still reeling from compatriot and fellow female highflyer Rita Jeptoo's failed A-sample test for EPO.

It was the friendly athletes' perfect answer to a waiting world on her ability to storm back to the high table of World Marathon Majors after missing the entire 2013 to welcome her second born Samatha and above all Cheap Men's Nike Air Max 90 Hyperfuse White Blue , it ended her Big Apple title heartache at her third time of asking.

Keitany's 2:25:07 victory in extremely windy and cold conditions will not be remembered for blistering times she's reputed for, but for being gladly welcomed with open arms by athletics purists worldwide for two reasons.

It was her first race over the meanest 42.195km distance since finishing fourth at London 2012 Olympics where she was expected to strike gold in a redeeming act for her embellished reputation after electing to take a maternal break, a truly heart-warming story that sprinkled human touch in a fiercely competed sport.

Coming against the gloomy backdrop of Jeptoo's doping stunner that sparked international outrage, casting aspersions on a nation with a strong distance running heritage, Keitany spared the sport further unwelcome scrutiny when she edged Jemimah Sumgong for the crown by three seconds Cheap Men's Nike Air Max 97 2017 Retro Black Gold , tying for the closest finish to a women's race in New York in history following 2004 when another Kenyan, Susan Chepkemei lost out to Britain's great Paula Radcliffe by the same wafer thin margin.

Sumgong is a training partner of Jeptoo at Rosa Associati management camp in Kenya with the two sharing Italian coach, Claudio Berardelli, who alongside his boss and agent Federico Rosa, were quick to disassociate links with the provisionally suspended star.

A New York victory for Sumgong would have kicked-off a fresh damning inquest notably in Western media that is want to question booming performances by Kenyan runners as much as they celebrate their feats.

Having learned of the scandalous development moments ahead of her pre-race press conference dominated by Jeptoo's failed drug test Cheap Men's Nike Air Max 97 KPU Grey , Keitany, 32, did not hide her disdain upon returning home, calling for stern action against doping by an Athletics Kenya (AK) accused of leniency in tackling the matter.

"Victory came as the country's athletics program is under scrutiny. The women's field received a jolt Friday with the news that Rita Jeptoo of Kenya, the winner of the 2013 and 2014 Boston and Chicago Marathons Cheap Men's Nike Air Max 97 2017 Retro Black , tested positive for a banned substance in an A sample.

The triumph was even sweeter when her well calculated breakaway four miles when the course had turned away from wind rendered Firehiwot (sixth) and Kiplagat (13th) non-contenders setting up the titanic combat with Sumgong whom after initially trailing by a few paces in the last mile, summoned all reserves from her superior speed to finally prevail.

Keitany has trained her gaze at becoming the first woman since local idol Radcliffe to notch a London hat-trick and the fourth in race history follo. Jerseys From China   NFL Jerseys For Cheap   College Jerseys Wholesale   NBA Jerseys From China   Soccer Jerseys China   College Jerseys China   MLB Jerseys Free Shipping   NHL Jerseys Free Shipping   New NFL Jerseys Cheap   Nike NBA Jerseys Cheap