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The strange behaviour of the oobleck can now be predicted by researchers

The strange behavior of the Oobleck can now be predicted by researchers

Oobleck is a strange material that is also referred to as a non-Newtonian fluid. This weird substance behaves sometimes as a liquid and a solid the other times. It is made of water and corn-starch entertaining children for many hours. If it is punched it appears to be solid but if picked up it flows away. 

Scientists at MIT have studied the magic substance and published a 3D mathematical model that can predict when the oobleck can change from solid to a liquid and vice versa. The findings are published in the PNAS journal. 

The scientists explain that the fine particle suspensions demonstrate drastic changes in viscosity on shear which produces interesting behavior. This is captivating to both children and rheologists. In the model, researchers have introduced a 3D continuum model with the help of mixture theory coupling the particle and fluid phases. 

The term oobleck is derived from a green substance in the book Bartholomew and the Oobleck authored by Dr. Seuss. This has fascinated researchers for a long period of time as its behavior depends on the way it is interacted with. 

The size of the particles plays an important role in this ability of the non-Newtonian fluids. The particles of corn starch are a fraction of the size of a sand grain, so due to their small size, they can be influenced by the temperature and electric charges around them. On moving slowly through the oobleck, the grains repel each other however on hitting it fast, the particles touch giving the feel of a solid. According to Ken Kamrin, mechanical engineer, MIT although this can be created very easily the rules governing it are complex.

This research can be mostly considered as a recreational work, scientists think that this modeling can be used to test oobleck for several materials such as bulletproof vests. Although it is an important question if it can stop a bullet. 

Researchers had been working on a model for wet sand but had to change it to obtain the desired oobleck variables. They ran experiments to check if the model was perfect, such as squeezing it between plates and shooting a projectile to a tank having the substance. An X shaped wheel ran through the material at different speeds to help understand the behavior. The model was able to predict the change of oobleck from liquid to solid substance and vice versa as the wheel rolled back. 

Journal Reference: PNAS

 

Creators of the lithium ion battery awarded 2019 Nobel Prize in Chemistry

Creators of the lithium-ion battery awarded the 2019 Nobel Prize in Chemistry

The 2019 Nobel Prize in Chemistry has been awarded to John B. Goodenough, M. Stanley Whittingham, Akira Yoshino by the Royal Swedish Academy for developing lithium-ion batteries. 

The Nobel committee has stressed the importance of this technology which has given us the freedom to use and enjoy portable devices such as laptops, mobile phones to even electric cars and spacecraft. The lithium-ion batteries can be easily recharged by plugging them into the mains power supply. 

To perfect such technology, there were many challenges. Lithium can release electrons easily, thus making it suitable to store and conduct electricity. However, since it is quite reactive, it has to be adjusted for making it functional inside a battery. 

A battery comprises the cathode(positive side) and anode(negative side). Dr. Whittingham was working on energy technologies that are free from fossil fuel in the 1970s, which is when he discovered a method to make cathode for a lithium battery made from titanium disulfide. It was good however the anode was made from metallic lithium making it quite explosive to work with. Dr. Goodenough improved on this in 1980, using cobalt oxide to prepare the cathode. This increased battery voltage. 

The anode in previous batteries was made from lithium metals making it not so safe to work with as it was highly reactive. Dr. Yoshino focused on this problem as he created an anode from petroleum coke where the carbon layers allowed the lithium ions to be present between them. Ions moved across batteries as electrons moved in the circuits thereby powering the devices. This whole process is reversible hence this can be repeated many times. So the battery can be charged as many times as possible before it started deteriorating. The first lithium-ion battery that was commercially viable was created by Yoshino in 1985.  

Dr. Goodenough is now the oldest person to win a Nobel Prize at 97 years of age as he surpassed Dr. Arthur Ashkin who won the Nobel Prize for Physics last year. Yoshino mentioned during the announcement of the award that the prime motivation for continuing the research was simply their curiosity. 

Only five women have been awarded the Nobel Prize in Chemistry out of 203 Chemistry Nobel Laureates since 1901. 89 of these recipients were awarded for carrying out work in the United States while only 60 were actually born. 

Check out the Nobel Prize winners from the field of Medicine and their discovery.

Curiosity obtains traces of salt in the last lakes of Gale Crater

Curiosity obtains traces of salt in the last lakes of Gale Crater

The lakes on Earth turn salty on drying out and the same incident happened when the Curiosity Mars climbed to identify the younger rocks. It found some of the salts which were left behind gathering insights on life could have prospered, rather than the mere survival on Mars. Gale crater was selected in part as it provides the possibility to investigate sedimentary rocks of different ages layered on top of each other. Curiosity has found periodic clay-bearing deposits containing 30-50 percent calcium sulfate by weight as reported in a Nature Geoscience paper.

All the rocks are 3.3-3.7 billion years old dating to the Hesperian period. Likewise, rich deposits have not been found in the older rocks of the crater. According to Dr. William Rapin of the California Institute of Technology and co-authors, the salts are present due to the percolation in the rocks by the waters of the bygone lakes which were very salty. Older rocks were much less salty although they were also exposed to the waters. Curiosity might detect more recent examples even though the younger ones were never touched by water.

Like a desert lake on Earth, the waters of the Gale crater evaporated, leaving a saltier residue, but it was an intermittent process on Mars that lasted 400 million years. The rocks have been subjected to forces of weathering over this vast time period even without water, and the calcium sulfate-enhanced portions are more resistant to erosion, producing mini versions of the formations in places such as Monument Valley, where harder rocks extend above the terrain.

Curiosity found a 10-meter (33-feet) slope containing 26-36 percent magnesium sulfate, in the 150 meters (500 feet) of calcium sulfate-enriched layers. Researchers believe that before the deposition of more soluble salts, it precipitated out first.

The paper mentions that their outcomes do not compromise the life search in the Gale crater. Terrestrial magnesium sulfate-rich and hypersaline lakes are known to sustain halotolerant biota while the preservation of biosignatures may be supported by crystallization of sulfate salts.

The occasional bursts of salty water are observed even today hence it is not unique to Gale crater in having such salts. As the planet dried, sulfate deposits have been identified by Martian orbiters across several places on Mars and it is the first instance where a rover has been operated its instruments over these samples. The periodic bursts of sulfate salts found by Curiosity showed Gale crater had many rounds of drying with several wet periods rather than one single great drought.

Journal Reference: Nature Geoscience

Researchers fabricate all-perovskite tandem solar cells with improved efficiency

Researchers fabricate all-perovskite tandem solar cells with improved efficiency

A kind of solar cell having an important perovskite structured element known as Perovskite tandem solar cells (PSCs) has been fabricated by a group of scientists from Nanjing University, China and the University of Toronto, Canada. Hairen Tan, the lead researcher told that instead of making single-junction perovskite solar cells, the primary idea was to make more efficient all-perovskite tandem solar cells. The findings are reported in Nature Energy journal.

Perovskites are a group of minerals having the same crystal structure as perovskite which is yellow, black or brown mineral comprising mostly of calcium titanate. Many researchers over the past few years have been attempting to build solar cells using this material, either wide-bandgap (~1.8 eV) or narrow-bandgap (~1.2 eV) perovskites.

Merging wide and narrow bandgap perovskites together could enhance power conversion efficiency (PCEs) than that achieved by single-junction cells without any increase in fabrication costs. Scientists need to find a method to strengthen the efficiency of individual subcells, while also integrating the wide and narrow-bandgap cells synergistically for building this type of cell.

Tan said that low efficiencies (PCE~18-20 percent) and low short-circuit current densities (Jsc~28-30 mA/cm2) have been demonstrated by the mixed Pb-Sn narrow-bandgap perovskite solar cells which fall under their capacity, and under the performance of the best Pb-based single-junction perovskite cells. One of their vital components, Sn2+, readily oxidizes into Sn4+ is responsible for the weak performance in narrow-bandgap perovskite solar cells. Tan and his team wanted to determine solutions that could overcome the high trap densities and short carrier diffusion lengths exhibited by the resultant cells.

He also added that their main purpose is to extend the diffusion of narrow-bandgap perovskite solar cells thus to achieve better-performed tandem solar cells. Also, they took a perspective to stop the oxidation of Sn2+ to Sn4+ in the precursor solution to enhance charge carrier diffusion length and whose inclusion in the mixed Pb-Sn perovskites causes Sn vacancies. A new chemical method was used by Tan’s team that is based on a comproportionation reaction and leads to significant improvements in the charge carrier diffusion lengths of mixed Pb-Sn narrow-bandgap perovskites. This could eventually increase the performance of PSCs.

The team obtained an extraordinary 3 μm diffusion length that allows performance-record-breaking Pb-Sn cells and all-perovskite tandem cells unlike the earlier intended method characterized by sub-micrometer diffusion lengths, that can reduce the efficiency of the cell. He also explained that a tin-reduced precursor solution was developed to obtain this by restoring the Sn4+ (an oxidization product of Sn2+) back to Sn2+ through comproportionation reaction in the precursor solution.

The major challenge for the advancement of solar cells with a perovskite element is the oxidation of tin-containing perovskites as it adversely affects their efficiency and hampers their utilities. A substitute path for fabricating tandem solar cells using tin-containing narrow-bandgap perovskite is given by the new chemical method introduced by Tan and his co-workers making cells more stable and efficient.

Tan added that the electronic quality of tin-containing perovskites is comparable to that of lead halide perovskites that have shown efficiency similar to crystalline silicon cells. This approach will eventually provide them a way to very inexpensive and highly efficient solar devices.

The performance of monolithic all-perovskite tandem cells was tested using the chemical approach after fabrication. Remarkable independently approved PCEs of 24.8 percent for small-area devices (0.049 cm2) and 22.1 percent for large-area devices (1.05 cm2) was obtained by their cells. Additionally, after functioning for over 400 hours at their highest power point under full one sun illumination, the cells retained 90 percent of their performance. The method introduced by this team of scientists could lead to the development of more efficient and cost-effective solar-powered devices in the future.

Tan said that they are now planning to further enhance the power conversion efficiency of all-perovskite tandem solar cells above 28 percent. Minimizing the photovoltage loss in the wide-bandgap perovskite solar cell will be the primary feasible method to attain this while minimizing the optical losses in the tunneling recombination junction is another possibility.

Journal Reference: Nature Energy

Researchers awarded the Nobel Prize in Medicine for their discovery of cells adapting to low oxygen

Researchers awarded the Nobel Prize in Medicine for their discovery of cells adapting to low oxygen

The Nobel Assembly has awarded the 2019 Nobel Prize in Physiology or Medicine to William Kaelin, Sir Peter Ratcliffe, and Gregg Semenza for their discoveries of the ways in which cells sense and adapt to the availability of oxygen.

The molecular switch that helps our cells to adjust to lowering oxygen levels was discovered by the three researchers. This is necessary because it offers a hypoxic reaction when the oxygen levels change i.e. the change when altitude changes, when exercising or when getting a cut.

There are various ways by which our body handles this such as forming new blood vessels, increase of blood cell production, cells adapting to certain metabolic changes. An example of the latter situation is the production of lactic acid in muscle cells during heavy exercise. The energy captured in food is released by the cells using oxygen in a reaction called aerobic respiration. Cells can also perform anaerobic respiration to avoid using oxygen but this is not sustainable as well as inefficient in the long term for humans. The three Nobel laureates and their colleagues discovered this ability to switch from one mode to the other.

It is known that the increase in the erythropoietin hormone (EPO) is produced by the kidneys in low-oxygen conditions and in anemic people. Semenza, working at Johns Hopkins University demonstrated that the increase in EPO which stimulates the production of red blood cells is stimulated by a specific gene known as hypoxia response element or HRE.

HIF-1α is one of the proteins produced by the gene found to be oxygen sensitive which disappears in the abundance of oxygen. The cells were more likely to show symptoms of hypoxia which lack the von Hippel-Lindau gene (connected to cancer). This was discovered by William Kaelin and his team from the Dana-Farber Cancer Institute.

A relation between VHL and HIF-1α was created by Ratcliffe and his group from Oxford University and the Francis Crick Institute. They figured out the molecular details of the working of these mechanisms and also that the protein cannot be destroyed without the gene. From general metabolism and exercise response to embryo development and the functioning of the immune system, HIF-1α plays very crucial roles. It also affects conditions like anemia, cancer, strokes, and heart attacks. At present, EPO is being studied as a potential method to fight against the cancer cells by preventing them access to oxygen and nutrients.

High value chemicals for pharmaceuticals could be made cheaper and greener by new catalysts

High value chemicals for pharmaceuticals could be made cheaper and greener by new catalysts

Chemicals used to make pharmaceuticals could be made more sustainably by a new series of catalysts

– The catalysts made by researchers at the University of Warwick and GoldenKeys High-Tech Materials Co., Ltd. in China can tailor make chemicals

– The ability to selectively make the chemicals means they can potentially be made quicker, cheaper and higher purity

High value chemicals used to make pharmaceuticals could be made much cheaper and quicker thanks to a series of new catalysts made by scientists at the University of Warwick in collaboration with GoldenKeys High-Tech Co., Ltd. in China.

The process of making high-value chemicals for uses such as the pharmaceutical or electronics chemical industry requires many years of work and a very high financial investment, with a large amount of side products going to waste.

However, in research published in August in the ACS journal Organic Letters, the paper: Probing the Effects of Heterocyclic Functionality in [(Benzene) Ru (TsDPENR)CI] Catalysts for Asymmetric Transfer Hydrogenation’, shows how scientists are able to tailor conditions in the catalyst to make the molecule required.

The research project between the University of Warwick and the GoldenKeys High-Tech Materials Co., Ltd., a Speciality Material Company led by Dr. Yingjian Xu FRSC in China, has resulted in the development of a series of new catalysts for the asymmetric synthesis of alcohols which could be used for high value chemicals such as pharmaceuticals and electronics chemicals, potentially making it faster, cheaper and more environmentally sustainable as less chemicals are required under the catalytic conditions.

Researchers were able to make the catalyst by making the molecules’ ligands – which act as building blocks, bind to the metal ruthenium.

This means that scientists can pick and choose which molecules to bind together to make a catalyst and in turn make the chemical required in a much faster and more sustainable way.

In some cases the ligands are ‘bidentate’ – meaning they form two bonds to the metal, and in other cases they are ‘tridentate’ – forming three bonds to the metal. Knowing how each ligand will bind also helps the identification of the optimal active form and the conditions required for the target application.

Professor Martin Wills from the Department of Chemistry at the University of Warwick comments:

“The ability to make high-value chemicals through our new series of catalysts using ruthenium metal means that they can be made much more sustainably.From left to right Jonathan Barrios-Rivera, Martin Wills, Yingjian Xu (Andy)

Dr. Yingjian Xu of GoldenKeys High-Tech Materials Co., Ltd. adds:

“If this method is used in the pharmaceutical and electronics chemical industries for example then products and intermediates can potentially be made more cheaply and quickly with higher purity for consumers and reduce waste as less material is needed to make the catalyst, unlike traditional stoichiometric methods.”

Materials provided by University of Warwick

DNA structure

New evidence of forces responsible for separation of DNA discovered

According to a piece of new evidence, the force which holds the DNA might also be responsible for change of shape so that its repair, gene shuffling and copying can take place. The iconic double helix structure of our DNA was discovered back in 1950. It has a structure similar to that of a twisted ladder in which the nitrogen base pairs in the middle are held by the hydrogen bonds. The findings appear in the Proceedings in the National Academy of Sciences. 

These bonds are considered as a “fundamental paradigm” because of their role in holding the DNA together. However, apart from this, one important consideration is that they are water-repelling or hydrophobic. 

Replication of DNA occurs with the help of many enzymes, in which DNA molecules are essentially unzipped by enzymes by the removal of hydrogen bonds. But this might not be the only way to do it. Scientists from the Chalmers University of Technology, Sweden have tested the DNA in an increased hydrophobic environment where they found that the water-repelling force can also be used for unraveling it. It loses its structure in a water-repelling environment when a solution of polyethylene glycol is added which is a semi-hydrophobic solution. 

Bobo Feng, lead author, and the chemical engineer said that the DNA is protected by the cells and not exposed to the hydrophobic environments that might have harmful molecules. But for its use, the DNA has to be opened up. It is kept in a water solution most of the time but the environment changes to a hydrophobic one when the DNA has to be edited, copied or repaired. 

Steven Brenner, a NASA molecular biophysicist said that although this is an important discovery of a new technique of melting the DNA for its repair, it has not been covered accurately by the media. The results do not suggest that hydrogen bonds are not important for the formation of DNA while the hydrophobic forces are. This is not a new idea as models considering hydrophobic interactions in the DNA date back to the 1990s. Researchers in 1997 tested the idea that only hydrogen bonds are sufficient to keep the double helix of DNA together. It was confirmed by a later study in 2004 that hydrogen bonding was not necessary for the stability of base pairs. A 2017 study revealed that cells are not affected by the lack of complementary hydrogen bonds as the synthetic bases are translated with the help of only hydrophobic forces. 

Floyd Romesberg, lead author of the 2017 study and a biochemist said that complementary hydrogen bonds might be considered the main definitions of DNA and RNA however there are other forces that can take part in the processes of information retrieval and storage. It often occurs that the biases of the chemist separating the molecules get reflected in the analysis of the model rather than the molecules themselves. Benner feels that self-explanations can convince us to understand what is happening if the models allow us to actually make things. 

Currently, both the concepts of hydrogen-bonding and hydrophobicity help us to make advances in human medicine besides powering NASA’s search for extraterrestrial organisms. 

Feng said that it was not surprising that this behavior was not identified to date as DNA was never placed in a hydrophobic environment. 

Journal Reference:  PNAS  (Proceedings of the National Academy of Sciences of the United States of America)

Mass of Neutrinos that has perplexed the concepts of Physics has been narrowed down

Mass of Neutrinos, the perplexing concept of Physics has been narrowed down

An enormous experiment to pin down the mass of one of the most perplexing particles in the Universe has placed a cover on how massive the neutrino really might be.

What was once considered massless, is now thought that the mass of the particle weighs no more than one electronvolt. It may not be an accurate response, but it brings us one step closer to a satisfactory solution to one of the greatest secrets of modern physics.

Neutrinos are odd. They are among the Universe’s most abundant particles, yet challenging to identify. Because of their unique characteristics, they communicate very little with ordinary matter.

Billions of neutrinos are currently zipping through your body. You can see why it’s called’ particles of the ghost.’

After years of testing of their plant in Germany, the Karlsruhe Tritium Neutrino (KATRIN) test started its test campaign to calculate the resting mass of the neutrino last spring.

At a meeting in Japan earlier this month, officials produced their first batch of results.

The findings have still not been released, and while there’s a long way to go, the researchers have divided estimates that were previously considered as possible, down from the previous upper limit of around 2 electronvolts to just 1.

Unlike units of pounds and kilograms, this measurement isn’t an easy one to picture. MIT physicist Joseph Formaggio and leading member of the KATRIN experimental group suggests starting tiny and then going more diminutive.

“Each virus is made up of roughly 10 million protons,” Formaggio said to MIT News writer, Jennifer Chu.

“Each proton weighs about 2,000 times more than each electron inside that virus. And what our results proved is that the neutrino has a mass less than 1/500,000 of a single electron!”

As it happens, nobody is astounded that the base mass of a neutrino may be so inconceivably low. When they were first recommended as part of the Standard Model of particle physics, it was assumed the particles didn’t have any mass at all.

This assumption was empirically challenged during the late 1990s by the results of a landmark experiment demonstrating neutrinos streaming from the Sun changed form in a way that meant their mass couldn’t be zero.

So if it’s not zero, what is it? For more than two decades, various experiments have done their best to constrain the limits on just how big or small it might be.

The main issue is that neutrinos do not interact with other particles. The only interaction they have is with the kind of particles we build measuring tools from via the nuclear force.

“Neutrinos are strange little particles,” says physicist Peter Doe from the University of Washington.

“They’re so universal, and there’s so much we can learn once we determine this value.”

 

Student makes discovery of an unusual mineral inside a diamond

Student makes discovery of an unusual mineral inside a diamond

A Ph.D. student at the University of Alberta has found a new and extraordinary mineral in a South African mine in a diamond.

The mineral which is named Goldschmidtite in honor of Victor Moritz Goldschmidt, the founder of contemporary geochemistry, has a unique chemical signature from Earth’s mantle for a mineral, stated Nicole Meyer, a Diamond Exploration Research and Training School graduate student.

Goldschmidtite has elevated levels of niobium, potassium and rare earth elements lanthanum and cerium, while the remainder of the mantle is dominated by other components, such as magnesium and iron, remarked Meyer. For potassium and niobium to constitute a significant percentage of this mineral, it must have developed under extraordinary procedures that have focused on these different components. The researchers estimate that the diamond containing the Goldschmidtite was formed about 170 kilometers beneath the surface of the Earth in temperatures that were almost 1,200 C.

As it is challenging for workers to drill down through the Earth’s crust to reach the mantle, scientists rely on tiny mineral inclusions within the diamonds to get to know more about the Earth’s chemistry deep within the surface.

“The discovery gives us a picture of fluid methods that affect the deep roots of continents during diamond formation,” stated Meyer’s co-supervisor, Graham Pearson, who added there had been numerous attempts to name new minerals after Goldschmidt, but previous ones have been undermined. “This one is here to stay.”

diamond discovery

“One person does not do the work that goes into finding a new mineral,” replied Meyer, who is also studying under the supervision of Thomas Stachel, professor, and Canada Research in Diamonds. “It has been an interdisciplinary collaboration with mineralogist Andrew Locock, crystallographers from Northwestern University, my advisers Thomas and Graham, and technicians.”

The study, “Goldschmidtite, (K, REE, Sr)(Nb, Cr)O3: a New Perovskite Supergroup Mineral Found in Diamond from Koffiefontein, South Africa,” was published in American Mineralogist.

 

MIT Scientists Uncovers the Existence of A New Blackest Substance

MIT Scientists Uncovers the Existence of A New Blackest Substance

What’s the darkest kind of black in your imagination? Black noir, Coal Black, Jet Black or anything you can count on. MIT scientists have made the discovery of a super black material. It has been claimed that this black substance is by far more darker than Ventablack.

A trending study in journal ACS Applied Materials and Interfaces reveals that a material made up of carbon cylinders organized on an aluminum foil surface is able to absorb more than 99.995 percent of light form possible angle is nearly 10 times blacker than any other property ever found on the planet Earth.

This much darker foil is out for a public display at the New York Stock Exchange as a precious phase of an art exhibition called “The Redemption of Vanity.” It has been reported that foil hits the price of $2 million diamonds.

This blackest ever material was invented by a professor of aeronautics and astronautics at MIT named Brian Wardle and a materials scientist at Shanghai Jiao Tong University named Kehang Cui when they both were making their collective attempts of fixing an issue in regards of carbon nanotubes.

Wardle and Cui were hitting efforts to produce carbon nanotubes on aluminum plains for the purpose of exaggerating the conductivity of the foil. But at the time of this experiment, a thin membrane of oxide kept arising on the aluminum that advanced its current.

Cui found that placing the aluminum to saltwater resulted in dissolving the oxide which helped the team to construct nanotubes with a combination of powerful electrical characteristics. They did it on a forecasting basis. It has been stated in the study.

” I remember noticing how black it was before growing carbon nanotubes on it, and then after growth, it looked even darker,” Cui admitted. “So I thought I should measure the optical reflectance of the sample”.

In the beginning, they had absolutely no clue that this action is going to end up revealing the blackest substance ever came into existence in this universe. As soon as they saw the incredible blackish properties of this material they approached Diemut Strebe, MIT artist in residence for exhibiting the darkened diamond. The reason behind this intense blackness is the high light absorption proficiency of CNT.,

“Our group does not usually focus on optical properties of materials, but this work was going on at the same time as our art-science collaborations with Diemut, so art influenced science in this case,” says Wardle.

“CNT forests of different varieties are known to be extremely black, but there is a lack of mechanistic understanding as to why this material is the blackest. That needs further study,” Wardle says.

For instance, this ultra-black foil might prove to be a precious detection for other scientific moves such as for fighting up the blackout, a path in the galaxy by preferring the use of striking shadow of this black element. It was completely an incidental finding but now is topping the charts of some actual amazements.

Journal Reference: ACS Applied Materials and Interfaces