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The new form of carbon, which they call T-carbon, has very intriguing physical properties that suggest that it could have a wide variety of applications.

The scientists, Xian-Lei Sheng, Qing-Bo Yan, Fei Ye, Qing-Rong Zheng, and Gang Su, from the Graduate University of Chinese Academy of Sciences in Beijing, China, have published their study on the first-principles calculations of T-carbon in a recent issue of Physical Review Letters.
Allotropes are formed when the atoms in a substance that contains only one type of atom are arranged differently.

Although many substances have multiple allotropes, carbon has the greatest number of known allotropes. The three best-known carbon allotropes are amorphous carbon (such as coal and soot), graphite, and diamond. Since the 1980s, scientists have been synthesizing newer allotropes, including carbon nanotubes, graphene, and fullerenes, all of which have had a significant scientific and technological impact.

With more recent advances in synthetic tools, scientists have been investigating a wide variety of new – and sometimes elusive – carbon allotropes. In light of these investigations, Sheng, et al., write in their study that it appears that we might be entering the era of carbon allotropes.

Here, the scientists explained how to obtain a new carbon allotrope by substituting each carbon atom in diamond with a carbon tetrahedron (hence the name “T-carbon”). They were inspired by the substitution of each carbon atom in methane with a carbon tetrahedron, which forms tetrahedrane.

“[Our study] adds a possible new allotrope of carbon with amazing properties,” Su told PhysOrg.com. “T-carbon has bond angles different from graphite and diamond, but the interesting structure is still quite stable and has the same group symmetry as diamond, thereby widening people’s vision and knowledge on carbon bonding.”

Each unit cell of the T-carbon structure contains two tetrahedrons with eight carbon atoms. As the scientists’ calculations showed, T-carbon is thermodynamically stable at ambient pressure and is a semiconductor. T-carbon is one-third softer than diamond, which is the hardest known natural material. The new carbon allotrope also has a much lower density than diamond, making it “fluffy.”

The scientists also calculated that T-carbon has large interspaces betweenatoms compared to other forms of carbon, which could make it potentially useful for hydrogen storage. In addition, the unique physical properties of this new carbon allotrope make it a promising material for photocatalysis, adsorption, and aerospace applications.
“We believe that, if obtained, T-carbon is so fluffy that it can be used to store hydrogen, lithium, and other small molecules for energy purposes,” Su said. “It can be used as photocatalysis for water-splitting to generate hydrogen, or as an adsorption material for environmental protection. As it has very low density but a high modulus and hardness, it is quite suitable for aerospace materials, sports materials like a tennis racket, golf club, etc., and cruiser skin, and so forth.”

The scientists also noted that T-carbon could have astronomical implications as a potential component of interstellar dust and carbon exoplanets.

New carbon allotrope could have a variety of applications

The structure of the new carbon allotrope, T-carbon, is shown from different directions. T-carbon is obtained by replacing each carbon atom in diamond with a carbon tetrahedron. Image credit: Sheng, et al. ©2011 American Physical Society.

“There is a long-standing puzzle in astronomy known as the ‘carbon crisis’ in interstellar dust,” Su said. “Observations by the Hubble telescope revealed that the carbon budget in dust is deep in the red, and there is not sufficient carbon in dust to account for the light distortions.”

In addition, the exoplanet WASP-12b has recently been found to have a large amount of carbon, making it the first carbon-rich exoplanet ever discovered. Since the structure of the carbon in WASP-12b is still unclear, T-carbon might also be one of possible candidates for this carbon planet.
To investigate T-carbon further, the researchers would like to synthesize the new allotrope in the lab, although they say that this would likely be very difficult.

“A synthesis of T-carbon in the lab poses a great challenge for materials scientists and chemists,” Su said. “We suggest the following ways: using the CVD technique under a negative pressure environment; detonation on diamond or graphite; crystallization of amorphous tetragonal carbon; or stretching cubic diamond under extremely large strength.”

Source: PhysOrg

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By Admin (from 17/08/2011 @ 14:00:57, in ro - Stiinta si Societate, read 652 times)

 Lider marcant si carismatic al Revolutiei bolsevice din octombrie 1917, Lev Davidovici Bronstein, ramas în istorie ca Leon Trotki, a fost unul dintre artizanii rasturnarii tarismului si, ulterior, a regimului lui Kerenski. Nascut în acelasi an ca si Stalin – 1879, el a îmbratisat înca de tânar cauza revolutionara si, desi initial s-a situat pe pozitii divergente fata de Lenin, în final va colabora cu acesta la succesul Revolutiei, dovedindu-se un priceput diplomat si mai ales un excelent strateg militar, în calitatea sa de Comisar al Poporului pentru politica externa si, ulterior, de întemeietor si prim comandant al Armatei Rosii si Comisar al Poporului pentru aparare.

Este greu de spus de altfel care ar fi fost sansele de succes ale bolsevicilor în lupta contra Albilor (partizani ai tarismului) si al fortelor interventioniste occidentale daca la conducerea Armatei Rosii nu s-ar fi aflat Leon Trotki. Dupa moartea lui Lenin, Trotki a intrat în conflict deschis cu succesorul acestuia la conducerea Partidului Comunist, Stalin. În contradictie cu politica stalinista a fauririi socialismului într-o singura tara, Trotki a pledat pentru raspândirea ideilor comuniste în întreaga lume si a militat pentru o „revolutie permanenta”.

De asemenea, a sustinut, în opozitie cu Buharin, renuntarea la Noua Politica Economica, initiata de Lenin dupa victoria Revolutiei si industrializarea rapida a URSS, ca singura cale de ajungere din urma a statelor dezvoltate din Occident. Stalin, un diletant în materie de economie, s-a opus, doar pentru a nu fi de acord cu cel pe care-l percepea ca fiind principalul sau rival. Duelul a fost pierdut de Trotki, care s-a vazut exclus din Partid în noiembrie 1927 si deportat mai întâi în Kazahstan, apoi exilat din URSS, în 1929.

Dupa multe peregrinari, a ajuns în Mexic, unde a scris o serie de lucrari referitoare la Revolutia bolsevica, prevazând ca din cauza greselilor comise URSS va sfârsi prin a reveni la capitalism. Supravietuind unei tentative de asasinat, comise în mai 1940, Trotki n-a mai fost la fel de norocos pe 21 august, când un agent stalinist, Ramon Mercader, l-a atacat, înfigându-i în cap un cutit de spart gheata. Trotki a murit a doua zi, fiind înmormântat în curtea casei unde locuise, la Coyoacan.

GABRIEL TUDOR - magazin.ro

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Basta guardare alle trasformazioni, spesso selvagge, delle nostre città e delle periferie per rendersi conto che il cemento e l’asfalto avanzano sempre di più, mentre scompaiono le superfici naturali. Il consumo di territorio è un fenomeno preoccupante che riguarda tutta l’Europa. Ogni anno mille chilometri quadrati di terreno, corrispondenti a un’area più estesa di Berlino, vengono sacrificati a vantaggio dell’espansione urbana e della costruzione di infrastrutture. Lo rivela il report “Overview of best practices for limiting soil sealing or mitigating its effects in EU-27”, presentato a Bruxelles nel corso della Green Week, che al tema ha dedicato una sessione. Questo assalto modifica per sempre le caratteristiche fisiche, chimiche e biologiche del suolo e si traduce in una perdita irreversibile. Per preservare questa risorsa, nell’ottica dello “using less, live better”, che è stato il tema di questa edizione della manifestazione europea, la Commissione propone un approccio basato sul “limitare, attenuare e compensare” il consumo di suolo.

In gergo tecnico si chiama “soil sealing” ed è quel processo di sigillatura o impermeabilizzazione causato dalla copertura del suolo con materiali impermeabili, dovuto appunto all’urbanizzazione e alla costruzione di infrastrutture. Questo processo modifica le funzioni del suolo provocando la perdita di terreni fertili e di biodiversità, la frammentazione dei paesaggi e, cosa ancor più grave, una ridotta capacità di assorbire e filtrare l’acqua, con il conseguente rischio di inondazioni devastanti. Secondo il report, tra il 1990 e il 2000 nell’Ue sono stati cementificati almeno 275 ettari di terreno al giorno, la metà dei quali occupati da edifici, strade e parcheggi. Negli ultimi anni c’è stato un rallentamento a 252 ettari al giorno dovuto alla crescita lenta della popolazione, ma il fenomeno resta comunque preoccupante. Tra il 2000 e il 2006 l’aumento medio di aree trasformate è stato pari al 3 per cento, con picchi del 14 per cento in Irlanda e Cipro, e del 15 per cento in Spagna. E in Italia? La situazione non è tra le peggiori: il consumo annuale di suolo è in diminuzione rispetto alla crescita della popolazione e il tasso di impermeabilizzazione è del 2,8 per cento, ma tra i territori ad alto rischio il rapporto segnala anche otto provincie italiane: Vercelli, Lodi, Verona, Piacenza, Parma, Campobasso, Matera, Catanzaro.

Un caso emblematico è proprio quello della provincia di Parma, la cosiddetta “Food Valley”, presentato alla Green Week grazie alla proiezione del film “Il suolo minacciato”. Negli ultimi anni nella Pianura Padana si sono persi migliaia di ettari di suolo agricolo e solo nella food valley parmense, dove si concentrano importanti produzioni agroalimentari, lo “sprawl” urbano (la dispersione) avanza al tasso di oltre un ettaro di suolo agricolo al giorno. “Il film nasce dalla constatazione di un problema che riguarda tutta l’Italia”, ci spiega Nicola Dall’Olio, regista del documentario. “L’agricoltura è espropriata dei suoi terreni, visti come una risorsa da sfruttare per la loro rendita immobiliare. Bisogna cambiare rotta, soprattutto considerando che le esigenze urbane potrebbero essere soddisfatte con la riqualificazione delle aree in disuso piuttosto che con nuove costruzioni”. Sullo schermo passano le interviste di esperti come Carlo Petrini di Slow Food, il climatologo Luca Mercalli e il sociologo Wolfgang Sachs, alternate alle immagini di gru, strade, capannoni, scheletri di costruzioni disseminati negli spazi verdi appena fuori le città. Una corsa all’accaparramento di suolo che non trova giustificazione: il tasso di crescita della popolazione è stabile e la situazione sociale è diversa rispetto a quella dell’urbanizzazione degli anni ‘60-70. Il motivo reale è la speculazione edilizia, “favorita dalle leggi che privilegiano lo sviluppo basato sul calcestruzzo a quello agroalimentare”. Il risultato è la comparsa sul territorio di capannoni che, dice Luca Mercalli nel film, “sono brutti, devastano e limitano la fruizione turistica e soprattutto sono vuoti, non calibrati sulle reali necessità…monumenti allo spreco che hanno sacrificato la produttività dei suoli migliori”. Come far fronte al problema? Il documentario suggerisce le possibili strade per preservare la risorsa suolo e i modelli di sviluppo urbano alternativi sulla scia delle esperienza della Germania e della Francia o di piccoli comuni come Cassinetta di Lugagnano (Mi).

Anche la Commissione Europea, in attesa di una direttiva in materia, indica le buone pratiche da seguire e propone un triplice approccio. Per prima cosa, ‘limitare’ l’impermeabilizzazione del suolo introducendo dei limiti, ottimizzando la pianificazione territoriale o ridefinendo i sussidi che incentivano le pratiche di ‘soil sealing’. In questo senso rappresentano buoni esempi quelli di Portogallo, Svezia, Spagna e Paesi Bassi, che stanno migliorando la qualità della vita e dei servizi in alcuni centri urbani per attrarre nuovi residenti e controbilanciare la dispersione territoriale. Oppure i progetti di Regno Unito, Francia, Repubblica Ceca e Fiandre, che incoraggiano lo sviluppo di nuove infrastrutture su vecchi siti industriali e commerciali dismessi. Poi bisogna ‘attenuare’ gli effetti del consumo di suolo, sostituendo l’asfalto o il cemento con superfici permeabili e costruendo tetti verdi, come stanno facendo diverse città in Germania, Danimarca e Austria. Infine, ‘compensare’ le perdite attuando misure di recupero in altre aree o con una riqualificazione di terreni già impermeabilizzati come accade in Repubblica Ceca e in Slovacchia.

Fonte: galileonet.it

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Their Gravity Power Modules would marry traditional heavy rig drilling technology with renewable energy storage.

 

At utility-scale, the pumped storage would begin with drilling thousands of feet underground, large enough to accommodate an 18 foot diameter storage shaft and a 6 foot diameter return pipe.

Here’s how it works, in the elegant words of Powermag:

“At the bottom of the shaft is a large concrete piston fitted to the shaft, called the “weight stack.” Also bored into the ground is a parallel but smaller-diameter “return pipe” that is connected to the main shaft at the top and bottom.

Finally, the entire volume is filled with water and tightly sealed—air is compressible and its presence reduces the system effectiveness. In essence, the position of the weight stack in the shaft determines the amount of energy stored.

During the energy storage process, off-peak electricity is used to power a pump that pushes water down the return pipe that will raise the weight stack from the bottom of the deep storage shaft.

During a peak electricity demand period, the weight stack is released, which pushes the water up the return pipe, reversing the direction of rotation of the pump-turbine and producing electricity, much as in a typical pumped storage hydroelectric plant.”

CEO Jim Fiske envisions that his Gravity Power Modules would be installed in clusters to produce the amount of energy desired. The storage capacity of a 7 acre site could amount to more than 2 GW (2,000 MW) depending on the depth and diameter of the shafts.

The Gravity Power Module has a conversion efficiency that looks likely to be in the 75% to 80% range once it is tested at full scale, at installation costs a little higher pumped hydro, around $150/kWh for a system capable of storing about 200 MWh.

Pumped hydro installation has installation costs of around $100/kwh. But it can be controversial because, like hydro-electricity itself, pumped hydro can impact a natural habitat for fish. More than half the states that have renewable energy standards do not allow hydro to qualify as renewable because of the ecological damage.

New pumped hydro projects face formidable permitting obstacles, despite the need to add more energy storage as we move to a clean power economy. The Gravity Power Module could be one of the solutions.

Source: CleanTechnica

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Utilizing the friendship paradox - the idea that a person's friends are likely more popular than they are - the researchers were able to follow groups closer to the center of a network without the tedious and difficult chore of fully mapping social networks. Members closer to the center of a network have contact with more people and are more likely to contract any contagious disease than people toward the outskirts of the group.

Social Networks Predict Disease Spread

Dr. Nicholas Christakis of the Harvard Medical School and his collaborator Dr. James Fowler at UCSD tracked 319 randomly selected Harvard students through the 2009 flu season as well as 425 students named as friends by the original group using two different methods of identifying the flu. The flu manifested itself in the friends group two weeks sooner than in the random group using one identification method and 46 days sooner using the other method.

The sooner outbreaks of infectious disease are identified, the sooner they can be treated and, hopefully, contained. Even a two week head start as seen in the more conservative identification method could make an enormous difference in the size and severity of a major outbreak. That said, it's likely the amount of lead time inherent in this method will likely vary from case to case depending on the specifics of the infection and the details of the network. It also depends on actively monitoring a network likely to be affected by disease before it strikes.

In addition to tracking infection diseases, the friends paradox could also be used to track other things that spread out among groups of people including trends, the adoption of specific behaviors, and the effectiveness of marketing campaigns.

TFOT previously reported on another social networking research project involving the voluntary publication of data collected via RFID chips, the decision by the individuals of who individuals should see the information and what data they decide to delete or retain for public consumption. TFOT also reported on the origins and spread of infectious diseases including a historical overview of smallpox and a video about the H1N1 flu epidemic.

Source: TheFutureOfThings.com

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By Admin (from 16/08/2011 @ 11:00:18, in ro - Stiinta si Societate, read 726 times)

 Asemenea lui Che Guevara sau Marilyn Monroe, chipul lui Einstein e vazut peste tot: in reviste, pe afise, tricouri, timbre, brelocuri. Aceasta intruchipare a geniului stiintific a aparut intr-o imagine faimoasa dupa ce si-a scos limba in fata lumii. A aparut pe bicicleta; arborându-si pene pe cap; in pijama in fata bibliotecii, cu acelasi chip de savant excentric si binevoitor, „viu si surâzator” cum il descria Romain Rolland.  Albert Einstein s-a nascut in Ulm (Germania) in 1879, intr-o familie de evrei. A inceput sa vorbeasca destul de târziu.

Era considerat lenes, incapatânat, rebel, un elev indisciplinat, dislexic si chiar retardat. Cu toate astea, preocuparile sale pentru stiinta debuteaza la vârsta de 4 ani, când se intereseaza de functionarea busolei. La 10 ani intelegea teorema lui Pitagora iar la 13 il citea pe Kant. Notele sale publicate in diverse biografii nu sunt cele ale unui elev indolent. Era doar refractar la disciplina de fier a gimnaziului din Munich. Sub presiunea unor profesoare, va parasi gimnaziul inainte de a-si termina studiile secundare si va pleca in Italia, apoi in Elvetia in 1895. Isi va lua cetatenia elvetiana ceea ce-l va scuti de serviciul militar si se va inscrie la Scoala politehnica din Zürich.

Intuitia unui „mutant”

Mitul lui Einstein s-a nascut in 7 noiembrie 1919. In acea zi, astronomul englez Arthur Eddington a anuntat rezultatele unei expeditii pe care a facut-o cu câteva luni in urma in insula Principe, o mica colonie portugheza din largul coastelor Africii occidentale. In timpul acestei misiuni, un grup de savanti a putut sa observe si sa fotografieze devierea razelor luminoase in timpul unei eclipse totale de Soare, un „detaliu” care a confirmat validitatea teoriei relativitatii generale enuntate de Einstein in 1915. A doua zi, lumea a aflat acest lucru iar fizicianul german care lucra la biroul de brevete din Berna, devine un star mondial. Cel mai mare savant dupa Newton. Emblema sa: E = mc2.

Descoperirea, de o extraordinara complexitate, e efectiv rodul unui creier de exceptie. „Einstein face parte dintr-o specie de «mutanti» a apreciat fizicianul  Stephane Durtand, autor al relativitatii animate. Nimeni n-ar fi putut avea intuitia unei ecuatii atât de complicate si care e atât de departe de realitatea experimentala”. Complexitatea teoriei sale a jucat fara indoiala un rol important in elaborarea mitului. Dar aspectul ei universal e cel care a contribuit la celebritatea savantului intrucât vizeaza problema naturii spatiului si a timpului, doua concepte care se afla in miezul vietii umane.

Relativitatea, care avanseaza idei aparent paradoxale (timpul nu se scurge cu aceeasi viteza pentru toti – traim intr-o a patra dimensiune) se ofera, intr-o oarecare masura, imaginatiei sau a visului. Marturie stau piesele de teatru sau a romanele inspirate de geniul lui Einstein, printre cele mai cunoscute opere numarându-se „Intâlnirea cu diavolul” de Dino Buzzati sau „Einstein” de Ron Elisha. De obicei, amploarea inteligentei si universalitatea teoriilor sale nu sunt suficiente pentru a explica popularitatea lui Einstein care n-ar fi devenit una dintre icoanele secolului XX, daca n-ar fi asociat contextului istoric.

Un promotor al pacii

In 1919, Europa incepea sa se dezmeticeasca in urma primului razboi mondial. Savantii englezi recunosc faptul ca un german de origine evreiasca a reusit sa bulverseze cunostintele legate de legile Universului ceea ce e interpretat ca un gest de reconciliere intre popoare. Un simbol prin care stiinta triumfa asupra neintelegerilor si a ororilor razboiului. Oamenii, epuizati timp de 4 ani de distrugeri si sacrificii, sunt avizi de noutati. Apar Sigmund Freud, victoria lui Lenin, vârsta de aur a automobilului lui Henry Ford. Carismatic, cu totul special, Einstein avea toate datele pentru a se integra in aceasta galerie de personaje.

Pacifist convins, va folosi popularitatea sa pentru a promova pacea. Va proslavi crearea Israelului. Evreii ii vor fi recunoscatori si ii vor cere sa-i succeada la conducera Statului evreu lui Chain Weizmann. Afinitatile cu miscarile sioniste vor atrage asupra sa fulgerele grupurilor antisemite. Si in sânul fizicienilor germani exista o miscare antisemita. Pentru acestia, Einstein era intruchiparea fizicii evreiesti: o fizica decadenta, abstracta, teoretica, nicidecum experimentala. In 1933, când Hitler ajunge la putere in Germania, Enstein se afla intr-o calatorie in SUA. Ramâne aici si-i ajuta pe evrei sa scape din regimul nazist.

Un mit construit din contraste

In acest mit cu lumini si umbre isi va gasi locul si un fals istoric, extrem de raspândit, prin care Einstein e considerat „parintele bombei atomice”. In 1933, fizicianul a redactat o scrisoare adresata presedintelui Roosvelt, avertizându-l ca germanii erau pe punctul de a realiza bomba atomica. Nu se stie daca acest gest l-a influentat pe presedinte in decizia de a lansa proiectul Manhattan al fabricarii bombei atomice, proiect la care Einstein nu a participat.

Ceea ce a contribuit la falsul istoric a fost deschiderea magazinului Time in iulie 1946 in care fotografia savantului apare cu o ciuperca atomica pe fundal pe care se poate citi ecuatia E = mc2. O alaturare abuziva, fara implicarea lui Einstein. De ce atâtea extrapolari? Pentru ca mitul se hraneste din contraste. Totul e construit antitetic in istoria lui Einstein: geniul care era „falimentar” la scoala; savantul imbatrânit, depasit de noua generatie; pacifistul care a participat la elaborarea bombei atomice, toate astea contribuind la dimensiunea tragica a personajului.

Jurnalistii si biografii n-au incetat sa scormoneasca in viata sa privata pentru a-i detecta punctele slabe; fisurile. A fost infierat, atribuindu-i-se o legatura amoroasa cu o spioana rusa. A fost considerat un sot rau in relatia cu Mileva Marie, prima sa sotie (un mariaj dezastruos). Nu a fost menajat nici in postura de parinte care si-a distrus psihic copiii. (Prima fata s-a nascut handicapata iar cel de-al treilea copil, Edouard, era atins de schizofrenie). La 50 de ani dupa moartea sa, mitul nu si-a pierdut din vitalitate. Un mit ce continua sa seduca lumea stiintifica, a artelor si nu in ultimul rând, cea comerciala.

DORIN MARAN - magazin.ro

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E le nanotecnologie possono dare una mano. Lo ha spiegato Jeeson Reese, della Strathclyde University (Glasgow, UK), che usando una simulazione al computer, ha esaminato le reali possibilità di raggiungere questo obiettivo utilizzando i nanotubi di carbonio.

Il sistema analizzato e descritto da Reese, pubblicato su Physics World, si basa sul processo di osmosi inversa. In un normale processo di osmosi, l'acqua con la concentrazione più bassa di soluti disciolti oltrepassa spontaneamente una membrana permeabile per andare a diluire quella con più soluti, in questo caso l'acqua salata. Al contrario, per ottenere il passaggio inverso viene applicata una pressione maggiore all'acqua salata, che in tal modo è spinta ad attraversare la membrana, lasciando il sale da parte e unendosi a quella potabile. Questo metodo permette di dissalare l'acqua, ma produrre la pressione necessaria al processo ha un costo molto elevato.

Ed è qui che intervengono i nanotubi, separando meglio l'acqua dai sali disciolti e aumentando l'efficienza della membrana. Infatti, solo poche molecole d'acqua per volta riescono ad attraversare i minuscoli pori presenti tra gli atomi di carbonio, alla stessa velocità delle membrane tradizionali, mentre non possono passare gli ioni di sodio e di cloro o gli altri  minerali. In tal modo, le prestazioni del sistema sono migliori, la pressione necessaria ad effettuare l'osmosi inversa diminuisce, e così anche il costo della dissalazione.

Secondo il modello descritto dello scienziato, grazie ai nanotubi si possono avere membrane per osmosi inversa venti volte più permeabili alle molecole d'acqua, e molto più efficienti nell'allontanamento degli ioni salini, rispetto a quelle attualmente in commercio. Pertanto, come spiega lo stesso Jeeson Reese: “anche se molte questioni rimangono ancora aperte, la grande potenzialità delle membrane di nanotubi di carbonio nel trasformare i processi di dissalazione e purificazione dell'acqua è chiara, ed è un uso delle nanotecnologie positivo e socialmente utile”.

Fonte: galileonet.it

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Automakers are now one step closer to being able to replace this long-standing technology with laser igniters, which will enable cleaner, more efficient, and more economical vehicles.

In the past, lasers strong enough to ignite an engine's air-fuel mixtures were too large to fit under an automobile's hood. At this year's Conference on Lasers and Electro Optics (CLEO: 2011), to be held in Baltimore May 1 - 6, researchers from Japan will describe the first multibeam laser system small enough to screw into an engine's cylinder head.

Equally significant, the new laser system is made from ceramics, and could be produced inexpensively in large volumes, according to one of the presentation's authors, Takunori Taira of Japan's National Institutes of Natural Sciences.

According to Taira, conventional spark plugs pose a barrier to improving fuel economy and reducing emissions of nitrogen oxidessmog. (NOx), a key component of

Spark plugs work by sending small, high-voltage electrical sparks across a gap between two metal electrodes. The spark ignites the air-fuel mixture in the engine's cylinder—producing a controlled explosion that forces the piston down to the bottom of the cylinder, generating the horsepower needed to move the vehicle.

Engines make NOx as a byproduct of combustion. If engines ran leaner – burnt more air and less fuel – they would produce significantly smaller NOx emissions.

Spark plugs can ignite cleaner fuel mixtures, but only by increasing spark energy. Unfortunately, these high voltages erode spark plug electrodes so fast, the solution is not economical. By contrast, lasers, which ignite the air-fuel mixture with concentrated optical energy, have no electrodes and are not affected.

Lasers also improve efficiency. Conventional spark plugs sit on top of the cylinder and only ignite the air-fuel mixture close to them. The relatively cold metal of nearby electrodes and cylinder walls absorbs heat from the explosion, quenching the flame front just as it starts to expand.

Lasers, Taira explains, can focus their beams directly into the center of the mixture. Without quenching, the flame front expands more symmetrically and up to three times faster than those produced by spark plugs.

Equally important, he says, lasers inject their energy within nanoseconds, compared with milliseconds for spark plugs. "Timing – quick combustion – is very important. The more precise the timing, the more efficient the combustion and the better the fuel economy," he says.

Lasers promise less pollution and greater fuel efficiency, but making small, powerful lasers has, until now, proven hard. To ignite combustion, a laser must focus light to approximately 100 gigawatts per square centimeter with short pulses of more than 10 millijoules each.

"In the past, lasers that could meet those requirements were limited to basic research because they were big, inefficient, and unstable," Taira says. Nor could they be located away from the engine, because their powerful beams would destroy any optical fibers that delivered light to the cylinders.

Taira's research team overcame this problem by making composite lasers from ceramic powders. The team heats the powders to fuse them into optically transparent solids and embeds metal ions in them to tune their properties.

Ceramics are easier to tune optically than conventional crystals. They are also much stronger, more durable, and thermally conductive, so they can dissipate the heat from an engine without breaking down.

Taira's team built its laser from two yttrium-aluminum-gallium (YAG) segments, one doped with neodymium, the other with chromium. They bonded the two sections together to form a powerful laser only 9 millimeters in diameter and 11 millimeters long (a bit less than half an inch).

The composite generates two laser beams that can ignite fuel in two separate locations at the same time. This would produce a flame wall that grows faster and more uniformly than one lit by a single laser.

The laser is not strong enough to light the leanest fuel mixtures with a single pulse. By using several 800-picosecond-long pulses, however, they can inject enough energy to ignite the mixture completely.

A commercial automotive engine will require 60 Hz (or pulse trains per second), Taira says. He has already tested the new dual-beam laser at 100 Hz. The team is also at work on a three-beam laser that will enable even faster and more uniform combustion.

The laser-ignition system, although highly promising, is not yet being installed into actual automobiles made in a factory. Taira's team is, however, working with a large spark-plug company and with DENSO Corporation, a member of the Toyota Group.

Source: physorg

More information: CLEO: 2011 presentation CMP1, "Composite All-Ceramics, Passively Q-switched Nd:YAG/Cr4+:YAG Monolithic Micro-Laser with Two-Beam Output for Multi-Point Ignition," by Nicolaie Pavel of Romania's National Institute for Laser, Plasma and Radiation Physics; Takunore Taira and Masaki Tsunekane of Japan's Institute for Molecular Science; and Kenji Kanehara of Nippon Soken, Inc., Japan, is at 1:30 p.m. Monday, May 2 in the Baltimore Convention Center.

Provided by Optical Society of America

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An Indiana state Representative, who recently voted for a constitutional amendment that would ban gay marriage, has been accused of using Craigslist to offer an 18-year old male $80 for "a couple hours of your time tonight" plus a tip "for a really good time."

The Indianapolis Star obtained e-mails sent from Rep. Phillip Hinkle's (R) publicly listed personal address, responding to a Craigslist posting by Kameryn Gibson that said "I need a sugga daddy." Gibson told the Star that the post was in the "Casual Encounters" section under m4m, or men for men. He used his sister Megan's e-mail address -- and she later sent the e-mails to the Star.

Rep. Phillip Hinkle (R-IN)

"Cannot be a long time sugar daddy," says the e-mail response from what is allegedly Hinkle's address, "but can for tonight. Would you be interested in keeping me company for a while tonight?"

"I am an in shape married professional, 5'8", fit 170 lbs, and love getting and staying naked," the e-mail says.

Another e-mail says: "If u want to consider spending night u might tell ur sis so she won't worry. Would have u back before 11 tomorrow. No extra cash just free breakfast and maybe late night snack."

The Star reports:

The young man told The Star that they met, but that he tried to leave after the man told him he was a state lawmaker. He said the lawmaker at first told him he could not leave, grabbed him in the rear, exposed himself to the young man and then later gave him an iPad, BlackBerry cellphone and $100 cash to keep quiet.
Gibson had his sister pick him up, who says that she then received a number of calls, and one was from a woman who claimed she is Hinkle's wife. "I was like, 'Your husband is gay,'" Megan Gibson said. "And then she was like, 'You have the wrong person.'" When Gibson reportedly read back the e-mail address used for the Craigslist ad, the woman asked her not to call the police.

Megan Gibson told the Star that later that evening she went back to the JW Marriott to show Hinkle's daughter the e-mails. She soon after received another phone call from the woman claiming to be Gibson's wife, who offered her $10,000 not to tell anyone. Still another call came from Hinkle himself later, and she told him what she had told his family members. "You just ruined me," she says Hinkle responded.

Hinkle did not deny the e-mails in response to the Star's request for comment, but said: "I am aware of a shakedown taking place." He did not elaborate on what "shakedown" meant, nor did his attorney.

Read the full report here.

Hinkle recently voted for an amendment (.pdf) to the state's constitution that would define marriage as between a man and a woman.

Late Update: Gov. Mitch Daniels (R) weighed in on the allegations on Friday, telling reporters that he is "sad about it."

"It's not for me to say [whether Hinkle should resign]," Daniels said. "It's for him and his constituents. It's just a personal family tragedy."

Source: tpmmuckraker.talkingpointsmemo.com - Author: Jillian Rayfield

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By Admin (from 15/08/2011 @ 15:00:34, in en - Science and Society, read 751 times)

A federal appeals court in Atlanta ruled Friday that a provision in President Obama's health care law requiring citizens to buy health insurance is unconstitutional, but the court didn't strike down the rest of the law.

The decision is a major setback for the White House, which had appealed a ruling by a lower court judge who struck down the entire law in January. But given that another appeals court, in Cincinnati, has upheld the law, it is increasingly clear that the Supreme Court will have the final say.

"We strongly disagree with this decision and we are confident it will not stand," White House spokeswoman Stephanie Cutter said in a statement.

On Friday, the divided three-judge panel of the 11th Circuit Court of Appeals sided with 26 states that filed a lawsuit to block Obama's signature domestic initiative. The panel said that Congress exceeded its constitutional authority by requiring Americans to buy insurance or face penalties.

"This economic mandate represents a wholly novel and potentially unbounded assertion of congressional authority," the panel said in the majority opinion.

The majority also said that a basic objective of the law is to "make health insurance coverage accessible and thereby to reduce the number of uninsured persons." Without the individual mandate, the majority said, the law "retains many other provisions that help to accomplish some of the same objectives as the individual mandate."

The decision is a review of a sweeping ruling by a Florida judge, who not only struck down a requirement that nearly all Americans carry health insurance, but he also threw out other provisions ranging from Medicare discounts for some seniors to a change that allows adult children up to age 26 to remain on their parents' coverage.

The states urged the 11th Circuit to uphold U.S. District Judge Roger Vinson's ruling, saying in a court filing that letting the law stand would set a troubling precedent that "would imperil individual liberty, render Congress's other enumerated powers superfluous, and allow Congress to usurp the general police power reserved to the states."

The Justice Department countered that Congress had the power to require most people to buy health insurance or face tax penalties because Congress has the authority to regulate interstate business. It said the legislative branch was exercising its "quintessential" rights when it adopted the new law.

During oral arguments in June, the three-judge panel repeatedly raised questions about the overhaul and expressed unease with the insurance requirement. Each of the three worried aloud if upholding the landmark law could open the door to Congress adopting other sweeping economic mandates.

The arguments unfolded in what's considered one of the nation's most conservative appeals courts. But the randomly selected panel represents different judicial perspectives. None of the three is considered either a stalwart conservative or an unfaltering liberal.

The National Federation of Independent Business (NFIB), the only private group to join the 26 states in the lawsuit, cheered the decision.

"Small-business owners across the country have been vindicated by the 11th Circuit's ruling that the individual mandate in the health-care law is unconstitutional," said Karen Harned, executive director of the group's legal center.

"The court reaffirmed what small businesses already knew - there are limits to Congress' power. And the individual mandate, which compels every American to buy health insurance or pay a fine, is a bridge too far," she said.

Source: foxnews.com - The Associated Press contributed to this report.

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sir are you encouraging people participate in some kind of game? ...where people give up their power? It never worked before .... that’s why I suggest instead of give up your power, exercise it from y...
05/10/2014 @ 08:45:09
By James Smith
Asta e marihoana nu?ei cine te poate opri so faci ,eu nu prefer astfel de fistractie deoarece am vazut ca dupa nu mai faci altceva fecit ca dormi bine,nu am incercat nu incerc dar nu opresc pe nimeni ...
30/09/2014 @ 09:34:56
By Miulesvu Corina Lucia
tovaraseilor .. nu confundati un sifonar sau turnator cuun ofiter sub acoperire.. e o mare diferenta ...
29/09/2014 @ 13:07:51
By Alex Andu
... deci şi Toma e securist, logic!
27/09/2014 @ 15:49:04
By Bogdan Sith Huşanu
Mai voinicilor,voi nu stiati ca inainte de 89,securistii erau omul si copacul,,ei acum sint si mai multi,cred ca au dat si lastari,ce naiba..!..
27/09/2014 @ 15:45:01
By Toma Pasculea
E greu de crezut că mişcă ceva de calibru în massmedia din orice ţară care să nu aibă vre-o treabă cu 'serviciile'. Cred că massmedia, instituţiile me...
27/09/2014 @ 15:41:52
By Alterul EgoulMeu
Manipulare, marca Basescu.
27/09/2014 @ 15:38:18
By Stela Andreica


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