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INCENDIILE POT FI COMBATUTE CU AJUTORUL ENERGIEI ELECTRICE ?

One day firefighters may put out fire without the use of water and foam. In this picture, fire officers extinguish a burning barricade after protests in England.

Dan Kitwood / Getty Images

Pompierii vor putea stinge incendiile, fără sa mai utilizeze apă şi spumă. Cercetătorul  Ludovico Cademartiri de la Universitatea Harvard, a prezentat rezultatul  cercetarilor sale duminica, la American Chemical Society in Anaheim, California

Omul de stiinta a efectuat  un studiu care a demonstrat  ca o flacără de 50 cm  poate fi stinsa cu o baghetă metalica legată la un amplificator de 600 waţi.Cademartiri a  folosit un electrod metalic (în forma unui fir subţire de metal), l-au conectat la o sursă de înaltă tensiune şi a poziţionat acea sârmă în apropierea unei flăcări de gaz metan. Apoi, au pornit sursa de mare tensiune,  mărind si micşorand voltajul. Câmpul electric a separat  zona care arde de combustibilul care nu s-a aprins încă, oprind astfel incendiul.

Oamenii de stiinţă ştiau de 200 de ani că flăcările pot interacţiona cu câmpurile electrice, dar cele mai multe experimente au utilizat curent continuu, în loc de un curent alternativ.

Cademartiri a spus că este prea devreme pentru a spune cum ar putea afecta curentul electric o flacără de dimensiuni mari, dar este optimist cu privire la viitorul  acestei aplicatii tehnologice.

Sursa: NPR

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01/04/2011 Posted by | DIVERTSMENT | , , , , , , , | Lasă un comentariu

YEMENUL POATE DEVENI PRIMA TARA COMPLET LIPSITA DE APA.Yemen could become first nation to run out of water

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Criza ecologica generata de schimbarile din natura care conduc la  disparitia apei, ca  urmare a incalzirii globale si fenomenelor climatice extreme, a inceput sa afecteze din ce in ce mai mult viata oamenilor in diferite regiuni ale globului.

Si inca victime la nivelul tarilor.Specialistii avertizeaza ca in viitorul apropiat, Yemenul va deveni prima tara din lume care va ramane fara surse proprii de apa si ca vor urma si alte state…

Populatia acestei tari  arabe, este in mmarea ei majoritate dependenta de aprovizionarea cu camioane cisterna pazite de garzi inarmate pana in dinti. Apa de baut a devenit o raritate , iar apa pentru spalat este un lux pe care nu si-l mai permit, in prezent, decat oamenii foarte bogati. 

Yemenul devine prima tara din lume care ramane fara nicio sursa de apa. Cauzele sunt multiple si rezida, in principal, in schimbarile climatice care au dus la permanentizarea secetei in regiune, cresterea demografica fara precedent, razboiul civil care se poarta intre trei factiuni rivale peste care se suprapun adesea conflicte tribale. Ca si cum asta nu ar fi de ajuns, situatia este agravata de secarea ultimului izvor din tara.

Conform estimarilor specialistilor, aceasta stare de fapt va duce la mari migratii de oameni si la conflicte sociale extreme. Cantitatea de apa care-i revine anual fiecarui cetatean yemenit este de doar 100-200 metri cubi, in timp ce minimul international al consumului de apa / an este de circa 1.000 de metri cubi de persoana.

Yemen could become first nation to run out of water

 

One type of vehicle is always within sight on Yemen’s roads: the water truck.

The brightly coloured, dilapidated tankers, often driven by Kalashnikov-wielding tribesmen, travel winding mountain roads and cross deserts to bring Yemenis a commodity more precious than petrol. It is one that increasingly only the rich can afford, with supply through the water mains regularly cut off. Others must rely on scarce rain, charity or crime to stave off thirst.

Yemen is set to be the first country in the world to run out of water, providing a taste of the conflict and mass movement of populations that may spread across the world if population growth outstrips natural resources.

Government and experts agree that the capital, Sanaa, has about ten years at current rates before its wells run dry but the city of two million continues to grow as people are forced to leave other areas because of water shortages.

In Yemen, which is fighting three insurgencies, the battle lines of tribal wars have traditionally followed the lines of the wadis, desert valleys that become rivers when the rare rains fall. Amid one of the world’s highest rates of population growth — 3.46 per cent last year — the water shortage has become critical and is driving civil unrest.

Hannan, an 18-year-old mother of one from Lahej, near Aden, said that only the comparatively well-off could plan for cuts in supply. “In a good week we’ll have a water supply all week but then the following week there will be water only for a day or two,” she said.

She and her husband, a factory worker, pay 3,000 riyals (£9) for a week’s supply of water from a touring water truck when the taps run dry. With an income of only 20,000 riyals (£60) per month, this means the family often spend half their income on water.

“There are a lot of people who can’t afford it and they have to rely on their neighbours to help,” she said.

Her neighbour, Anisa, 40, said: “When the water goes, it’s a sign of trouble in the community.”

Water available across Yemen amounts to 100 to 200 cubic metres per person per year, far below the international water poverty line of 1,000 cubic metres.

Groundwater reserves are being used faster than they can replenish themselves, especially in the Sanaa basin, where water once found 20 metres below the surface is now 200 metres deep, and despite the rainwater tanks on the roofs of most houses.

In desperation some citizens have dug unlicensed wells, compounding the problem. In Taiz, in the south, tapwater is available only once every 45 days. In the mountainous Malhan district in the north, women and children climb a 1,500m mountain to collect water from a spring, often in the small hours to avoid long queues.

Hosny Khordagui, director of the water governance programme in Arab states at the United Nations Development Programme, said: “If they do not find a solution we will see people encroaching on big cities, the formation of slums, a rise in crime, venereal disease, violence, even fanaticism. Fanatics will find very fertile ground to recruit and develop their infrastructure.”

Yemeni citizens have lived on scarce water supplies for thousands of years but the problem has been exacerbated by widespread production of the local drug of choice, qat, which consumes up to 40 per cent of water. About 70 per cent of Yemeni men chew the leaves each day, and bushy qat trees are often the only spots of green in the dry landscape.

The Deputy Planning Minister, Hisham Sharaf, admitted: “We have a water shortage which reflects itself in fighting between the people . . . If we continue spending this much water on qat Sanaa has ten to fifteen years.”

The Government is considering a desalination plant for seawater, but this is an expensive solution and may come too late. The only other option is to cut down on the agriculture industry, importing even more food.

via The Times

21/12/2010 Posted by | PRESA INTERNATIONALA | , , , , , , , , , , , , , , , , , , , | Lasă un comentariu

Momentul optim in care se bea apa poate imbunatati sanatatea.

Doua pahare de apa imediat dupa trezire, ajuta la activarea organelor interne.

Un pahar de apa – 30 de minute inainte de o masa. Ajuta digestia.
Un pahar de apa inainte de a face baie. Ajuta la scaderea tensiunii sanguine.

Un pahar de apa inainte de culcare. Ajuta la evitarea unui atac cerebral sau de cord.

29/04/2010 Posted by | DIVERSE | , , , | Lasă un comentariu

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