Daily Archives: October 13, 2014

Γαλάζια ηλεκτρικά τόξα πλημμυρίζουν το δωμάτιο όταν το Z Machine τεθεί σε λειτουργία (Πηγή: Sandia National Laboratories)

Μια κολοσσιαία γεννήτρια που δημιουργήθηκε από το αμερικανικό Πεντάγωνο για προσομοιώσεις θερμοπυρηνικών εκρήξεων πέτυχε νέο ρεκόρ απόδοσης σε πειράματα πυρηνικής σύντηξης, ένα είδος πυρηνικής αντίδρασης που θα μπορούσε μια μέρα να προσφέρει ανεξάντλητη, καθαρή ενέργεια.

Το «Z Machine», μια γιγάντια πειραματική διάταξη στα Εθνικά Εργαστήρια Sandia στο Νέο Μεξικό, παράγει παλμούς ηλεκτρικής ενέργειας με ισχύ πολλών εκατομμυρίων Ampere. Το ρεύμα περνάει μέσα από μια μικρή κάψουλα με υδρογόνο, το οποίο φτάνει σε θερμοκρασίες εκατομμυρίων βαθμών Κελσίου και μετατρέπεται έτσι σε ήλιο.

Σε αντίθεση με την πυρηνική σχάση, η οποία απελευθερώνει ενέργεια από τη διάσπαση βαρέων στοιχείων όπως το ουράνιο, η πυρηνική σύντηξη αφορά τις αντιδράσεις που τροφοδοτούν τη λάμψη των άστρων, αντιδράσεις στις οποίες ελαφρά στοιχεία συνδυάζονται για να σχηματίσουν βαρύτερα.

Δεδομένου ότι η σύντηξη δεν παράγει μακρόβια πυρηνικά απόβλητα, ενώ το υδρογόνο που απαιτείται ως καύσιμο μπορεί να παραχθεί σε πρακτικά ανεξάντλητες ποσότητες με υδρόλυση του νερού, οι φυσικοί προσπαθούν εδώ και 60 χρόνια να δαμάσουν αυτή τη μορφή ενέργειας.

Είναι ένας δύσκολος στόχος, δεδομένου ότι οι συνθήκες που απαιτούνται για σύντηξη είναι πραγματικά ακραίες: οι πυρήνες των ατόμων είναι θετικά φορτισμένοι και απωθούνται, είναι επομένως δύσκολο να πλησιάσουν σε αρκετά μικρή απόσταση ώστε να αντιδράσουν. Για να συμβεί αυτό το οι πυρήνες πρέπει να συγκρουστούν με ταχύτητες γύρω στα 1.000 χιλιόμετρα το δευτερόλεπτο, κάτι που απαιτεί θερμοκρασίες γύρω στα 50 εκατομμύρια βαθμούς Κελσίου.

Σε όλο τον κόσμο δοκιμάζονται σήμερα διάφορες προσεγγίσεις. Η πλέον υποσχόμενη θα μελετηθεί την επόμενη δεκαετία στον Διεθνή Πειραματικό Θερμοπυρηνικό Αντιδραστήρα (ITER), στον οποίο ένα σύννεφο υπέρθερμου υδρογόνου θα συγκρατείται μετέωρο μέσα σε ένα ισχυρό μαγνητικό πεδίο. Μια δεύτερη προσέγγιση, η συμπίεση μιας κάψουλας υδρογόνου με ισχυρούς παλμούς ακτινοβολίας, δοκιμάζεται με τη βοήθεια του ισχυρότερου λέιζερ στον κόσμο.

Μέχρι στιγμής, πάντως, κανένα πείραμα σύντηξης δεν έχει καταφέρει να απελευθερώσει περισσότερη ενέργεια από αυτή που απαιτείται για τη θέρμανση του υδρογόνου -μια βασική προϋπόθεση για να γίνει πρακτικά βιώσιμη η νέα τεχνολογία.

Λίγο πιο κοντά σε αυτόν τον στόχο βρίσκονται πλέον οι ερευνητές του Ζ Machine, μιας γεννήτριας παλμών ηλεκτρικής ενέργειας που είχε αρχικά αναπτυχθεί για την προσομοίωση θερμοπυρηνικών εκρήξεων για λογαριασμό του Πενταγώνου (η ερευνητική υπηρεσία Sandia υπάγεται στο υπουργείο Άμυνας).

Στην καρδιά της πειραματικής διάταξης βρίσκεται μια κάψουλα με υδρογόνο (για την ακρίβεια περιέχει το ισότοπο του υδρογόνου δευτερίου) με διαστάσεις μόλις 5 x 7,5 χιλιοστά. Η τεράστια γεννήτρια στέλνει στην κάψουλα παλμούς ηλεκτρικού ρεύματος στην απίστευτη ένταση των 19 εκατομμυρίων ampere, οπότε δημιουργείται ένα ισχυρό μαγνητικό πεδίο που κάνει την κάψουλα να καταρρεύσει προς τα μέσα με ταχύτητα γύρω στα 70 χιλιόμετρα το δευτερόλεπτο, οπότε δημιουργούνται στο εσωτερικό της συνθήκες σύντηξης.

Στον τελευταίο γύρο δοκιμών το Z Machine θέρμανε το πυρηνικό καύσιμο στους 35 εκατομμύρια βαθμούς Κελσίου και οδήγησε στην απελευθέρωση περίπου δύο τρισεκατομμυρίων νετρονίων ανά βολή. Ο αριθμός των νετρονίων είναι μέτρο των αντιδράσεων σύντηξης, καθώς η σύντηξη δύο πυρήνων δευτερίου απελευθερώνει έναν πυρήνα ήλιου και ένα νετρόνιο.

Η παραγωγή πρωτονίων έχει πλέον αυξηθεί κατά 1.000 φορές σε σχέση με την απόδοση που προσέφερε το Z Machine πριν από μόλις έναν χρόνο, αναφέρουν οι υπεύθυνοι του πειράματος στην έγκριτη επιθεώρηση Physical Review Letters.

Παρόλα αυτά, η απόδοση θα πρέπει να αυξηθεί περαιτέρω κατά 10.000 φορές μέχρι να ξεπεράσει η ποσότητα της παραγόμενης ενέργειας την ενέργεια που καταναλώθηκε στο πείραμα, επισημαίνει στο Nature.com ο Μάικ Κάμπελ, ερευνητής της Sandia.

Το επόμενο βήμα για την επίτευξη αυτού του στόχου θα μπορούσε να έρθει με την αύξηση της έντασης του ηλεκτρικού ρεύματος στα 60 εκατομμύρια ampere. Η αναβάθμιση, όμως, δεν έχει ακόμα εγκριθεί.

Πηγή:in.gr

George Misalis arrives at the Supreme Court in a prison van. Picture: Jay Town

George Misalis killed his wife Zaharia in 2013 after a number of “stressors” in his life.

A 61-year-old Greek Australian man killed the love of his life after becoming depressed because he was under investigation for a rape case 30 years ago, and the couple’s home had been bombarded with misdirected phone calls to a Melbourne brothel, a court has heard.

George Misalis killed his wife Zaharia in March 2013 in a mystifying attack that he has been unable to explain, other than to claim she had made an inflammatory comment.

Misalis strangled his wife of nearly 40 years with a ligature in their South Morang home before stabbing her body with scissors.

At a plea hearing, his lawyer Peter Morrissey SC told Justice Betty King that Misalis had plunged into depression shortly before the murder.

This followed him being interviewed by police about a 30-year-old rape and falling from a balcony, rendering him unable to work.

“He had a number of stressors and he just wasn’t able to handle them,” Mr Morrissey said.

The couple’s home had also been subjected to repeated calls from ‘brothel seekers’ because their home number was similar to a brothel in Carlton.

“There were beastly individuals on the other end of the line,” Mr Morrissey said.

The couple had three children, who provided their father with a character reference.

Misalis initially pleaded not guilty to his wife’s murder but subsequently changed his plea to guilty, avoiding a trial.

He will be sentenced at a later date.

Source: Herald Sun

Leon’s “Watchful Cheetah” photo.

‘The Watchful Cheetah’, an image of a female big cat resting in the grass at the Maasai Mara reserve in Kenya, has propelled young Greek shutterbug Leon Petrinos into the under-10 category of the prestigious international competition for best Wildlife Photographer of the Year, presented by London’s Natural History Museum and the BBC, and celebrating its 50th anniversary this year.

Petrino’s image of the feline is among 42,000 photographs from 96 countries submitted to the competition. He was eight years old when he captured the shot while on safari in the east African country with his family.

“You can tell the animal’s feelings from the look in the eye, the way the fur lies and the ears move,” Leon says in the note accompanying his entry. He particularly likes portraits, he says, because “the animal’s feelings talk to you”.

Presenter at this year’s award ceremony at the Natural History Museum in London on October 21 is David Attenborough, who will announce the winners selected by a panel of judges, including American environmentalist and photographer Jim Brandenburg, Norwegian photographer Pal Hermansen and South Korean curator Sujong Song.

All 100 photographs will be exhibited at the NHM from October 24 to August 30.

Source: Kathimerini

Despite overwhelming public support to see the marbles returned, the British government is unmoved on the issue.

George Clooney’s new wife Amal Alamuddin might have stolen the limelight off the troop of four heading to Greece to help Greece’s case to the Parthenon Marbles, but its coordinator, Australian David Hill is confident the publicity will help put more pressure on the British.

Mr Hill has been in Greece for the past three weeks getting ready to meet with Greek Prime Minister Antonis Samaras, while working to assemble three famous international lawyers, Geoffrey Robertson, Amal Alamuddin and Professor Norman Palmer to work on a legal case to get the marbles back home.

As the president of the International Association for the Reunification of the Parthenon Sculptures, Mr Hill has seen years of talks between the two countries end fruitlessly, despite the tries of large international bodies like UNESCO.

The meeting scheduled for Tuesday and Wednesday will be the first time Greece will consider its legal options.

Mr Hill says it’s in Greece’s best interest to up the ante and address its legal rights.

“I don’t think it has any alternative,” Mr Hill told Neos Kosmos from Greece.

“I think Greece should now look at its legal entitlements and its legal rights and consider a legal claim.”

Mr Hill was asked by Prime Minister Samaras to assemble a group of prominent international lawyers to advise the government of what its legal claim
might be, resuming a plan Greece had in the works for years.

The former Papandreou government was set to do the same until the financial crisis stopped the talks.

Amal Alamuddin was actually going to be legal counsel on the topic in 2011 before the meetings were cancelled.

Now, a team of three coincidentally British high-profile lawyers will front the case for Greece.

Mr Hill, himself a British born Australian child migrant says he chose the three for their expertise in the field, not for their profile.

“I think we’ve got, in those three people it’s a repository of extraordinarily high calibre advice,” he says.

“You’d be hard pressed to do better.”

Greece has been reluctant in the past to start legal proceedings fearing it will look confrontational, but after 15 years of the same response from the British and trying everything in its arsenal to get them to the negotiating table, the government is out of patience.

If the case does reach litigation, it won’t be the first of its kind Mr Hill says.

“All over the world there where there is dispute on cultural property people resort to having the matter rationally and fairly sorted out through the judicial process,” he says.

“In fact a lot of people would say what took the Greeks so long to do this.

“It’s not a precedent, it’s far from it. It’s very reasonable and sensible.”

After so many years, the British approach to the matter hasn’t changed despite the growing international chorus of disapproval.

Surprisingly, British locals are very much in favour of returning the marbles to Greece. A poll in the Guardian newspaper saw 88 per cent of respondents want to see the marbles returned.

Sadly all three British prime ministers and the British Museum have been immovable on the issue.

In the meetings, Mr Hall and the contingent will also meet with Greece’s deputy prime minster Evangelos Venizelos, the culture minister Konstantinos
Tasoulas and director of the Acropolis Museum Dimitrios Pandermalis.

It’s hoped the government can decide on its next steps to tackling the issue before it becomes too late.

As a true Philhellene, Mr Hill says the issue is still as important as ever.

“There aren’t many situations where you come across a great wrong that can be righted. And here’s one that can be,” he says.

Married to a Greek woman, and with his 13-year-old son studying the language at Greek school, Mr Hill has never wavered from his campaign to have
the marbles returned.

“Since I first saw the Parthenon marbles in Athens in the sculptures in the British museum I always been struck by the injustice,” he says,
“It is a great wrong to leave these statues and sculptures in Britain. They should be in Greece.”

source: Neos Kosmos

Signed, sealed but not yet delivered: Greece’s Minister for Tourism Olga Kefalogianni and Immigration Minister Scott Morrison sign the Work and Holiday visa agreement in Canberra in May.

Neos Kosmos has identified that legislation in Greece to allow the program to start is yet to come before the Greek parliament, and before it does, it needs to jump the not inconsiderable hurdle of being signed by seven ministers, representing foreign affairs, tourism, health, the national economy, labour, education and development.

After being signed off at ministerial level, Neos Kosmos understands the bill will pass to the secretariat of the Greek cabinet, who will then brief the parliamentary committee on foreign affairs. Only then will it be finally voted on by the Greek Parliament.

A simple process it is not, and it is one that now begs the question as to whether the Greek Government has a motive for keeping the reciprocal visa on the shelf.

Greece’s Ambassador to Australia His Excellency Mr Haris Dafaranos explained his government’s actions this week, telling Neos Kosmos: “There is a ratification process which is continuing, and we the embassy have asked the competent authorities to expedite the process as soon as possible.”

A spokesman for Greece’s Ministry of Tourism followed suit, saying that verification of the agreement was “in process and will take some months.”
But while bureaucratic procedures may present a rational explanation, the Greek community in Australia has become increasingly exasperated over the affair, and its frustration has reached fever pitch.

While the convoluted workings of the Hellenic Republic’s internal bureaucracy is the prime suspect in the delay, others believe there may be more to the situation than meets the eye, with the problem going beyond a document lying forlorn in the bulging in-tray of a ministerial desk.

Despite Prime Minister Antonis Samaras recently talking up Greece’s ability to reduce unemployment next year, last week the OECD reported the country’s unemployment rate will remain around 27 per cent to the end of 2015.

Despite “moderate signs of recovery” according to OECD, the rate will remain stuck at close to its highest level since the onset of the economic crisis in 2008.

For young Greeks the situation is even worse. For the twelve months to July, the youth unemployment rate in Greece has hovered between 59 per cent and 51 per cent.

For some, it’s one reason why the Greek Government might find opening new doors to foreigners, eager to take the few jobs on offer, politically sensitive.

An alternative theory lies in Greece’s reticence to encourage a further brain drain, with many young Greeks continuing to look for opportunities abroad.

If either view holds any sway, going slow on ratifying the agreement and others like it, might be understandable in the ‘realpolitik’ affecting Greece’s coalition government that holds a narrow majority in the 300-seat parliament.

Victorian Federal MP Maria Vamvakinou, who took part in discussions over the visa’s introduction with Greece’s Deputy Foreign Minister Kosta Tsiaras last year, told Neos Kosmos that “given the protracted nature of this visa coming into affect, one can only now question the will of the Greek Government.”

“One has to ask, beyond due process, what other reasons might there be for their bureaucracy to stall?” said Ms Vamvakinou.

“Australia’s Greek community are frustrated over this issue, and are asking serious questions as to the Greek Government’s commitment to introducing the visa.”

President of the Greek Orthodox Community of Melbourne and Victoria, Bill Papastergiadis, said he was “dismayed and disappointed” that the visa’s introduction could still not be determined.

“We had a senior minister here in May who apparently ratified the agreement and we’ve heard absolutely nothing since.

“What the situation tells us, is that there is a complete lack of interest by the Greek Government on this issue, an issue so vital to the diaspora in Australia.”

Mr Papastergiadis, who was at the helm of GOCMV four years ago when it began lobbying the Australian and Greek governments to initiate the reciprocal visa agreement, said that Greece’s inaction since the agreement’s signing affected the standing of the Greek Government in Australia and globally.

“Working Holiday visa agreements have been ratified by Australia and are in force with practically every other European country,” he said.

“We will now write to Prime Minister Antonis Samaras on this matter to ask him personally to intervene and expedite the agreement.”

Meanwhile, an identical work and holiday visa agreement was signed by Australia with Poland on 28 March this year, just six week before Greece’s Tourism Minister Olga Kefalogianni and Immigration Minister Scott Morrison signed the Greece/Australia agreement in May.

Australia’s Work and Holiday visa program with Poland has been up and running since August 1.

source: Neos Kosmos

A couple visits the Parthenon hall at the Acropolis Museum in Athens on Friday. Human rights lawyer Amal Alamuddin Clooney, fresh from her marriage to Hollywood heart-throb George Clooney last month, is heading to Athens to advise the Greek government in its battle to repatriate the ancient Elgin Marbles statues from Britain.

The arrival of three London-based lawyers in Athens on Monday on the invitation of the Greek government, has caused a stir. Journalists are scrambling to get in touch with the prime minister’s office to find out every detail of their schedule and members of the public want to know whether they will have a chance to get a peek at them. But this excitement is hardly associated with the reason why the lawyers are coming to Greece, which is to explore the legal route for the return of the Parthenon Marbles from the British Museum to Greece. It is more likely linked to the fact that the youngest of the three visiting legal experts, 36-year-old Amal Alamuddin, recently became Mrs George Clooney after marrying the Hollywood star in Venice.

Needless to say, many in Greece think that the arrival of the lawyer has something to do with an off-the-cuff comment made by Clooney while promoting the film “The Monuments Men” in February, suggesting that the return of the sculptures that once graced the ancient citadel “is probably the right thing to do.” But the truth is that Alamuddin has been involved in the issue since February 2011.

It was then that David Hill, the English-born Australian archaeologist who chairs the International Association for the Reunification of the Parthenon Marbles and believes that Greece must take judicial recourse, asked Norman Palmer, a lawyer specializing in cultural heritage issues, to explore Greece’s legal options. The two men had met at a conference in Athens and had kept in touch over the years, so Hill was very familiar with Palmer’s numerous successes, including the return of Aborigine remains to Australia from London’s Natural History Museum.

Palmer accepted Hill’s request and sought the help of another lawyer he had worked with on the Australian claim, Geoffrey Robertson, known for his eccentric sartorial style and the important international cases handled by his firm, one of the biggest in London.

The two prestigious British lawyers and three more associates conducted exhaustive research into British law as well as exploring at which courts Greece could make its claim, and drafted a proposal. One of the signatures on the 10-page brief is that of Alamuddin.

Hill received the brief in 2011 and immediately got on a plane to Athens. The Foreign Affairs Ministry showed some interest at first, but a few weeks later Hill got a call saying that the time was not right for such a move because of the crisis. Hill decided to take one more trip when the new government was elected in 2012 and sought a meeting with Prime Minister Antonis Samaras, whom he had met in 2009 at the opening of the new Acropolis Museum. The two men had sat together for a moment and Hill shared with Samaras his thoughts for a more aggressive legal approach to the matter. Samaras was interested in what the British lawyer had to say and asked that they meet again. The meeting was delayed because of the elections but once Samaras became prime minister Hill sent the brief and the two men met again.

At that encounter the prime minister asked for a meeting with the legal team that put together the brief.

Their trip to the Greek capital had originally been planned to take place in the first half of September. Alamuddin and Clooney’s wedding pushed it to Monday.

According to the official schedule of the visit, the three lawyers will start with a tour of the Acropolis Museum and will then meet with Samaras, as well as Deputy Prime Minister and Foreign Minister Evangelos Venizelos and Culture Minister Costas Tasoulas, together with other officials from the ministries of Culture and Foreign Affairs.

source: ekathimerini.com

The International Monetary Fund will assist Athens’s project of disengagement from international funding, said Finance Minister Gikas Hardouvelis after his meeting with the IMG managing director, Christine Lagarde in Washington on Sunday.

“The IMF will be of assistance to the Greek effort in what we are trying to achieve,” Hardouvelis said after the half-hour meeting in the US capital.

According to a Fund statement on Sunday, talks focused on “the progress noted in the context of the program and the possible next steps.”

source: ekathimerini.com

An imposing mosaic of a man driving a chariot has been uncovered in the largest antique tomb ever found in Greece, in Amphipolis in northern Macedonia, the culture ministry said on Sunday.

Tiny pieces of white, black, blue, red, yellow and grey create a picture of a chariot drawn by two white horses, driven by a bearded man wearing a crown of laurel leaves.

Hermes, the messenger of the gods in ancient Greece, stands in front of the chariot.

“This mosaic, the largest on the site, measures 4.5 meters by three meters (14.8 by 9.8 feet) and is not completely uncovered,» a statement said.

The mosaic dates from the fourth century BC.

Archaeologists unearthed the enormous tomb dating to the time of Alexander the Great of Macedonia in early August.

There is widespread speculation over who was buried at the site: from Roxana, Alexander’s Persian wife, to Olympias, the king’s mother, to one of his generals.

source:ekathimerini.com