Tapping Tesla to Save Trapped Miners
by Phil Berardelli
on 20 August 2010, 5:30 PM
Lifesaving link. Trapped miners can use this magnetic wave generator and receiver to communicate with people on the surface. Credit: Diana Gerrish/Lockheed Martin Corp.救生鏈接，被困礦工可以使用此電磁波發生器和接收器，來地面的與人溝通。鳴謝：黛安娜傑里什 /洛克希德馬丁公司
In early January 2006, a methane explosion tore through a coal mine in Sago, West Virginia, trapping 13 miners nearly 100 meters underground. Cut off from communicating with the miners, authorities could not determine where they were—or even if they were still alive. By the time rescuers reached the miners 2 days later, all but one had died.
在2006年1月初，一次甲烷爆炸劃破一個在西弗吉尼亞州薩戈的煤礦，13名礦工被困地下近100米，切斷礦工的通訊，當局無法確定他們在那裡，或者甚至他們仍然是否活著。等到2天後救援人員到達礦工處，除一個全都已經死了。
After the incident, Gary Smith, a retired engineer, sent a letter to his ex-manager at the Lockheed Martin Corp. in Syracuse, New York. Smith, who grew up in a West Virginia mining family, asked his former colleagues if anyone knew of a technology that could provide reliable communications during such disasters. After reading reports of the Sago incident and discussing similar emergencies with federal mine safety officials, the Lockheed Martin engineers updated a very old one.
事件發生後，一位退休的工程師加里史密斯，寫信給他在紐約州錫拉丘茲洛克希德馬丁公司的前經理。史密斯生長在西弗吉尼亞州礦工家庭，他問以前的同事是否有人知道一種技術，可以在這樣的災難時提供可靠的通訊。在閱讀薩戈事件的報告和與聯邦煤礦安全官員討論類似緊急情況後，洛克希德馬丁公司的工程師更新一個很舊的。
The team focused on a concept developed over a century ago by Nikola Tesla. The noted pioneer in electricity and radio had shown that a magnetic wave generator could be used for wireless communications.
小組將重點放在一個於一個多世紀前由尼古拉特斯拉發展的概念，那電力和無線電的著名先鋒已展示，一個磁場波發生器可以用於無線電通信。
Basically, the generator works like an electromagnet. Powered by standard alternating current or battery, it runs electricity through a wire that is coiled around a metal cylinder, creating a harmless, low-energy magnetic field that extends for hundreds of meters. Just like radio, the field can carry an audio signal by modulating (raising or lowering) its strength instant by instant. But unlike radio, cell phones, and satellite phones—whose electromagnetic waves can't pass very far through rock, clay, or other materials that conduct electricity—a magnetically generated signal penetrates the ground easily. On the other end, a coiled antenna wire about 100 meters long receives the signal, and an amplifier converts it into sound.
基本上，發電機會像電磁鐵般工作，由標準的交流電或電池發動，它通過一電線纏繞一金屬氣瓶運行電力，創造一個無害、低能量的磁場，可伸延幾百米。就像收音機，以調製（提高或降低）它的強度磁場時時刻刻可携帶一音頻信號；但不同於收音機、手機和衛星電話 - 其電磁波無法通過岩石、泥土或其他材料很遠 - 那導電的 - 一磁產生的信號容易地穿透地面。在另一端，約 100米長的一條線圈天線線接收信號，及一放大器將它轉換成聲音。
In the 1890s, Tesla experimented with the concept as a possible alternative to Marconi's wireless telegraph. But the device's relatively short range and high signal noise made it impractical for widespread use. Short range is not a problem in most mine situations, explains engineer David LeVan, who led the Lockheed Martin research team. The devices the group developed, called the MagneLink Magnetic Communication System, combine a refrigerator-size magnetic generator with a briefcase-size receiving antenna. One such unit operates on the surface; the other, down in the mine. LeVan says tests earlier this year at a mine in Mavisdale, Virginia, showed that the low-frequency signal can penetrate through 500 meters of solid rock, making it usable in more than 85% of underground mines in the United States.
在19世紀 90年代，特斯拉試驗那概念作為一種對馬可尼的無線電報的可能選擇。但裝置的相對短距離和高信號噪音，使它不切實際作為廣泛使用。在大多數礦坑情況下短距離不是一個問題，工程師大衛萊解釋，他領導洛克希德馬丁公司的研究隊伍。小組開發的器件，叫做MagneLink磁通信系統，結合一個冰箱大小的磁發生器與一個公文包大小的接收天線。一個這樣的單位在表面上操作，另一個是在礦井下。萊文說今年早些時候在弗吉尼亞州Mavisdale的礦山的試驗，顯出低頻率信號可以穿透500米的堅固岩石，使它在美國可用於85％以上的地下礦井。
The team solved the problem of signal noise with the same type of digital signal-processing software used in cellular phones, LeVan says. The software also allows users to send and receive text messages. Although the units are rather bulky, they fit easily next to miners' emergency shelters with other lifesaving equipment. The underground transmission antenna is wrapped around one of the coal pillars that help to support the roof of the mine tunnel. A box made of polycarbonate (photo, in foreground) houses the receiving antenna.
Each generating unit can operate at least 24 hours on 12-volt battery power, which complies with U.S. Mine Safety and Health Administration (MSHA) requirements, and contains a telephone handset and text-message pad. Its low energy output means it poses no danger of sparking, which could set off an explosion if methane gas is present.
MagneLink program manager Warren Gross says that during field tests, miners offered many suggestions for making the units simpler to operate in emergencies. It's important, he says, that users need only turn the unit on, pick up the phone, and talk or text. Gross says the company is awaiting MSHA certification. If the agency approves the system, he says the units should start rolling off the assembly line by the end of this year.
Todd Moore, the director of safety services for CONSOL Energy, a coal-mining company in Canonsburg, Pennsylvania, says he has been advocating for this technology ever since the Sago disaster, which involved another coal company. "No one can predict what will be destroyed" in an explosion, says Moore, a lifelong mining safety engineer who assisted in the Sago rescue effort. "Our coal mines are the size of downtown Manhattan." Moore, who has supervised MagneLink tests but was not involved in the research, envisions each mine being equipped with at least several underground units, while topside units move around as necessary. "I am truly convinced [it] can save lives in the coal industry," he says.
http://news.sciencemag.org/sciencenow/2010/08/tapping-tesla-to-save-trapped-mi.html?rss=1
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