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Esential
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Luni, 29 Ianuarie 2024 16:55 |
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When you think of resources we’re running out of, sand might not be high on your list, but it’s up there thanks to our high demand for concrete. Scientists at Rice University have now shown that substituting graphene can not only save sand, but makes concrete lighter, stronger and tougher.
Despite being a sheet of carbon atoms just one atom thick, graphene has a reputation for being incredibly strong. As such, it’s no surprise that this 'wonder material' has been mixed into concrete before, usually to make it stronger and more durable. But that usually involves just adding graphene to the recipe – for the new study, the Rice team wanted to replace sand completely.
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International
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Joi, 25 Ianuarie 2024 19:02 |
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While we've seen quite a few filtration systems for making polluted water drinkable, many are quite complex, or utilize costly materials. By contrast, an experimental new setup simply requires users to inject dirty water through a layer of cellulose.
Developed by scientists from The University of Texas at Austin, the prototype device consists of a roughly hockey-puck-shaped housing, inside of which is a hydrogel film supported by a membrane full of microscopic pores.
The hydrogel is in turn made up of "an intertwined web" of cellulose nanofibers. Cellulose is the most common organic compound on Earth – it can be easily and inexpensively obtained from a wide variety of readily available natural sources, such as plants.
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Invatamant
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Vineri, 19 Ianuarie 2024 17:56 |
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HOTĂRÂRE DE GUVERN pentru modificarea anexelor nr. 1 şi 2 la Normele metodologice privind stabilirea salariilor de bază pentru funcţiile didactice de conducere de director şi director adjunct din învățământul preuniversitar de stat, precum şi pentru stabilirea categoriilor de unități de învățământ preuniversitar de stat în care se normează funcțiile de conducere didactice auxiliare de contabil-şef şi secretar-şef, cu nivel de studii S/M şi nivelul salariilor de bază aferente acestora, aprobate prin Hotărârea Guvernului nr. 598/2018
Actul normativ stabilește salariile de bază pentru fiecare funcție de conducere pe fiecare grad și fiecare categorie de unitate de învățământ, eliminând inechitățile salariale în ceea ce priveşte funcțiile didactice de conducere din sistemul de învăţământ preuniversitar, respectiv director, director adjunct, contabil-şef, secretar-şef, cu nivel de studii superioare (S).
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International
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Marţi, 16 Ianuarie 2024 18:59 |
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Astronomers have discovered a colossal cosmic structure that’s so big it threatens to undermine our entire understanding of the universe. The Big Ring spans about 3% of the radius of the entire observable universe – and it itself might be part of an ever bigger structure.
The Big Ring – a name that’s a hell of an understatement – is an almost perfectly circular group of galaxies and galaxy clusters with a diameter of about 1.3 billion light-years, and a circumference of around 4 billion light-years. If it was visible with the naked eye, it would be the size of 15 full Moons in the night sky.
It’s hard to overstate just how incredibly gigantic that is. Galaxy superclusters are usually the largest relatively common structure in the universe, measuring over a hundred million light-years wide. These can link up into filaments that stretch a few hundred million light-years long, forming part of the cosmic web.
Not only is the Big Ring bigger than those, but it’s bigger than should be possible for any structure to ever get. According to the Cosmological Principle, a fundamental part of physical cosmology, the universe should look uniform in all directions, for any observer anywhere within it. Sure, there are random variations in the distribution of stars and galaxies, but on the largest scales it all blends together into a homogenous pattern like static. The Cosmological Principle sets an upper limit of 1.2 billion light-years on the size of any structures – a limit that the Big Ring blatantly disregards. To continue the analogy, it would be nigh on impossible for the static on your TV to arrange itself into a big image of the Mona Lisa.
If it was a one-off find, it might be tempting to dismiss the Big Ring as an anomaly or a mistake. But it’s not the only “impossible” giant structure out there – and it’s not even the biggest. Two years ago the same astronomer, Alexia Lopez at the University of Central Lancashire, discovered a 3.3-billion-light-year-long crescent called the Giant Arc. In 2015 other scientists discovered the Giant GRB Ring, with a staggering diameter of 5.6 billion light-years. And then there’s the Hercules-Corona Borealis Great Wall, a galaxy filament that stretches an incomprehensible 10 billion light-years (although its status as a single structure is up for debate).
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Source: University of Central Lancashire
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International
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Luni, 15 Ianuarie 2024 09:52 |
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Madison Marsh, a 22-year-old second lieutenant in the US Air Force and master’s student at the Harvard Kennedy School’s public policy program, emerged victorious at the 2024 Miss America pageant in Orlando, Florida on Sunday night. Marsh, representing the state of Colorado, is the first active-duty Air Force officer ever to receive the national title.
Ellie Breaux of Texas placed as first-runner-up.
Fifty-one contestants participated in the event, representing all 50 US states, as well as the District of Columbia.
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