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Wednesday, September 30, 2015

Why is Ti(bpy) (CH3)4 Much more thermally stable than Ti(CH3)4?

In Ti(CH3)4 the metal is coordinatively unstaurated and the coordination sites required for decomposition reaction are avaliable (vacant) . There is easy pathway for thermodynamically possible decomposition reaction to occour. Hence Ti(CH3)4 is thermaly unstable, But in Ti(bpy)(CH3)4 has high thermal stablity due to the reasons that the coordination sites required for decomposition reaction to proceed are blocked.
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Why is the metallic atom in low oxidation state in metallic carbonyls?

The metal atom in metal  carbonyls is in low oxidation state. This is because if the fact that there is a higher electronic density (electronic charge) on the metal atom in its lower oxidation state than in its higher oxidaton state. Thus, since the metal is electroposative in nature, it would feel more comfortable if some of the excess electronic charge present on the metal atom gets transferred to the vacant pi-orbitals of CO (ligand) by forming M-CO pi-Bond.
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Monday, September 28, 2015

How Plastics-to-Fuel Can Become the Next Green Machine (Op-Ed)

Doug Woodring is director and co-founder of the Ocean Recovery Alliance, a nonprofit that brings together innovative solutions, technology, collaborations and policy to benefit ocean health. Steve Russell is vice president of the American Chemistry Council's Plastics Division, which leads efforts to "reduce, reuse, recycle and recover" more plastics through outreach, education and access to advances in technology. The authors contributed this article to Live Science's Expert Voices: Op-Ed & Insights.
We all know plastics deliver many benefits that make modern life possible. They help keep our foods fresher longer, reduce the weight of our cars so we use less fuel, insulate our homes so we use less energy, and keep countless medical supplies safe and sterile. While some plastics are recycled, far too many are not — and end up buried in landfills or littered where they can enter delicate marine ecosystems.
But new technologies that can harness the fuel content in non-recycled plastics could help remedy this. These technologies work as part of an integrated approach to managing waste geared toward creating value from trash — an approach dubbed sustainable materials management.
Cash from trash
One of the biggest benefits to this approach is that it helps everyone — from businesses to consumers to government — start to value materials that used to be "waste." And when people realize materials have value, everyone starts to think about how this value can be captured and put to work for communities. Not discarded. Not buried. And certainly not littered.
So why do plastics have an intrinsic value as a fuel source? Plastics are created primarily from energy feedstocks, typically natural gas or oil (mostly natural gas in the United States). The hydrocarbons that make up plastics are embodied in the material itself, essentially making plastics a form of stored energy, which can be turned into a liquid fuel source.
It makes sense that people are asking how to keep more of this valuable fuel in play, even after plastics are used, and how to keep it out of landfills.
One way, of course, is to recycle plastics whenever one can. Today, recycling technologies reprocess many common types of plastics: bottles, containers, cups, caps, lids and so on. Even many flexible plastics, such as bags and wraps, can be recycled at major grocery stores across the United States.
But what about the plastics that can't be economically recycled? They still contain embodied energy and largely untapped value as a new potential fuel source.
Getting fuel from used plastics
A new set of emerging technologies is helping to convert non-recycled plastics into an array of fuels, crude oil and industrial feedstocks. Processes vary, but these technologies, known as "plastics-to-fuel," involve similar steps.
Plastics are collected and sorted for recycling. Then the non-recycled plastics (or residuals) are shipped to a plastics-to-fuel facility, where they are heated in an oxygen-free environment, melted and vaporized into gases. The gases are then cooled and condensed into a variety of useful products. Plastics-to-fuel technologies do not involve combustion.
Depending on the specific technology, products can include synthetic crude or refined fuels for home heating; ingredients for diesel, gasoline or kerosene; or fuel for industrial combined heat and power.
Companies sell the petroleum products to manufacturers and industrial users, while fuels can help power cars, buses, ships and planes.
Economics will likely drive adoption of this technology. For example, by tapping the potential of non-recycled plastics, the U.S. could support up to 600 plastics-to-fuel facilities and generate nearly 39,000 jobs, resulting in nearly $9 billion in economic output from plastics-to-fuel operations. And that doesn't even include the $18 billion of economic output during the build-out phase.
Plastics-to-fuel technologies are increasingly scalable and can be customized to meet the needs of various economies and geographies, so they do not require huge machines. [Plant Plastics Seed New Tech, from Miatas to Tea Bags]
The promise of plastics-to-fuel is particularly exciting as an option to recover materials that today may be buried, or in some regions, illegally dumped or burned in open pits due to inadequate waste management infrastructure. The new facilities could create local revenue for communities in parts of the world where trash has become a hazard and a large source of marine litter.
A cleaner fuel
Another potential environmental benefit of plastics-derived fuels is that they can deliver a cleaner-burning fuel, due to the low sulfur content of plastics. Many developing economies currently use diesel with relatively high sulfur content.
The main product of fuel from plastic, when refined properly, is a diesel with greatly reduced sulfur content. Using
 this lower sulfur content fuel for boats, machinery, generators and vehicles can help decrease sulfur-related impacts while reducing non-recycled materials along the way.
Plastics-to-fuel technologies are expected to be particularly helpful in island nations where fuel prices are high and landfill options are limited. Communities now have the potential to create some of their own fuel locally, providing economic and environmental benefits, while removing a portion of the waste stream that potentially causes harm to their waterways, reefs, and tourism.
These are just some of the reasons our two organizations — one representing America's plastics makers, the other a nonprofit dedicated to a trash-free ocean — teamed up to create two new tools aimed at helping communities around the globe evaluate their potential to adopt plastics-to-fuel technologies.
The "2015 Plastics-to-Fuel Developers Guide" and the "Cost Estimating Tool for Prospective Project Developers"were designed to help potential investors, developers and community leaders determine whether this rapidly growing family of technologies could be a good fit for meeting local waste management needs and local demand for the relevant commodities.
Available at no cost, these tools provide, for the first time, an exploration of available commercial technologies, operational facilities and things to consider when developing a business plan.We first announced the tools at the fourth annual Plasticity Forum held in Cascais, Portugal, in early June. Each year, the Plasticity Forum draws hundreds of global thought leaders in the areas of policy, design, innovation, waste management, retail/brand management and more. And earlier this month, we introduced the tools at the Asia-Pacific Economic Cooperation's "Building Better Cities" Forum in Cebu, Philippines. Today, banks and investors are reviewing the online tools to evaluate investment opportunities. 
Source News from livescience

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Study finds benefits from lowering blood pressure, but questions remain

A new study proclaims some dramatic benefits of using medication to lower blood pressure, but some scientists are advising caution.
Aggressive treatment of high blood pressure comes with risks, and the study, a large clinical trial sponsored by the National Institutes of Health, has not yet been peer-reviewed or published.
Until then, changes to blood pressure guidelines and patient treatment plans should wait, says Sripal Bangalore, a cardiologist at New York University Langone Medical Center.
“The results look good, there’s no doubt about it,” he says. “But we need more details. We need to look at the data.”
Some experts caution that the study’s results may not be as impressive as they initially seem, and that NIH didn’t release enough data to put the findings in context. Plus, a low blood pressure treatment plan might not be right for every patient.
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Sunday, September 27, 2015

Apple releases iOS 9.0.1 with plenty of bug fixes

A week after iOS 9 launched, Apple has released iOS 9.0.1 with a host of bug fixes.
Among the iOS 9 bug fixes:
-- Fixes an issue where some users could not complete the setup assistant after updating, because the "Slide to Upgrade" function was unresponsive.

-- Fixes an issue where sometimes alarms and timers could fail to play.
-- Fixes an issue in Safari and Photos where pausing video could cause the paused frame to appear distorted.
-- Fixes an issue where some users who manually set up how their phones connect to their wireless networks could lose their data connections.
It's certainly not a big update, but it will allow a small group of people who were unable to upgrade to iOS 9 finally get the latest iPhone operating system. That unresponsive "Slide to Upgrade" bug was annoying to people who were eagerly waiting to get iOS 9, but couldn't.
Apple (AAPL, Tech30) made the new iOS available in a public beta for the first time this summer, allowing people to test out the new software. In theory, that should have helped reduce the number of bugs at launch.
Compared to previous versions of iOS, iOS 9 is (so far) pretty bug-free. The biggest problem so far was Apple's inability to satisfy demand, giving thousands of people headaches when they were unable to contact Apple's servers to download the new operating system.
Eventually, people were able to get the upgrade, however. In fact, Apple said iOS 9 has the fastest adoption rate of any iPhone operating system in history. 
News source : CNN news
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Facebook's Mark Zuckerberg pledges refugee camp internet access

Mark Zuckerberg: "We need to work together to make connecting the world a priority for everyone"

Facebook founder Mark Zuckerberg has announced plans to help bring the internet to UN refugee camps.
Speaking at a UN forum in New York, Mr Zuckerberg said it would help refugees access aid and maintain family links.
He also said Facebook would be part of a new campaign to make the internet available to everyone on the planet within five years.
He said the internet could help the UN meet its development goals and lift people out of poverty.
Signatories to the campaign, called the Connectivity Declaration, include rock star Bono, actress Charlize Theron, entrepreneurs Bill Gates and Richard Branson, and Wikipedia co-founder Jimmy Wales.
He said Facebook would work with the UN High Commissioner for Refugees.
"Connectivity will help refugees better access support from the aid community and maintain links to family and loved ones," he said. "Facebook is in a unique position to help maintain this lifeline."
Some three billion people around the world have internet access, and the connectivity campaign aims to bring the internet to the other four billion.
Mr Zuckerberg says that Facebook has nearly 1.5 billion users who log in once a month, and achieved a billion users in a single day for the first time last month.
He has predicted that the site's reach will continue to grow.
News Source: BBC news
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Saturday, September 26, 2015

What are π-acceptor and π-donor ligands?

Π-acceptor Ligands: Those ligands which empty π-orbitals with correct symmetry to overlap with the metal t2g orbitals forming metal to ligand π-bonds are called π-acceptor ligands. Eg CO, CN- NO- etc

π-donor ligands :
Those ligands which have filled π-orbitals with correct symmetry to overlap with the metal t2g orbitals forming ligand to metal π-bonds are called π-donor ligands eg.Halide ions, OH- NO3-

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What is Gold Number?

It is define as the number of milligrams of the protective colloid which prevent the coagulation of 10 ml of gold solution when 1ml of 10% Nacl solution is added to it. Lesser is the value of Gold no. higher will be the protective power.
Gold No of some protective power.
Gelatin----0.005
Albumen--0.08
Starch-----2.5
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Two new kidney cancer drugs 'work'

Two new therapies for hard to treat advanced kidney cancer could change treatment of the disease, say experts at the European Cancer Congress.

Both cancer drugs increased survival in trials which are also published in the New England Journal of Medicine and BBC health news online.
Both of the drugs are more effective. One drug takes the brakes off the immune system while the other stops growth signals in the tumour. Cancer Research UK said the developments will "greatly expand the arsenal" of available drugs. Kidney cancer is the eighth most common cancer in the UK and other country and survival rates plummet if it is caught late. Once the tumour has spread to other parts of the body then only one-in-10 people live for five years after diagnosis. The first trial, called Checkmate 025, used the immunotherapy drug nivolumab.
It is one of a suite of "checkpoint inhibitors" being developed by pharmaceutical companies that stop cancers turning off the immune system. They have already been proven effective in skin and lung cancers. The trial on 821 patients showed average survival was increased from 19.6 months with standard therapy, to 25 months with nivolumab.
Dr James Larkin, a consultant at the Royal Marsden Hospital, told the BBC News website: "It's another big day for immunotherapy for cancer and one of the biggest days for kidney cancer for some time. "We've known for two to three years that these drugs have efficacy in multiple types of cancer, but it's the randomised control trials that are important."

Strong results

The second trial, Meteor, used the targeted therapy cabozantinib on a trial of 658 patients.
It doubled survival from 3.8 months to 7.4 months. Prof Toni Choueiri, from Harvard Medical School, said: "An early evaluation of overall survival from the ongoing Meteor trial has shown a strong trend indicating that survival may be improved in patients receiving cabozantinib compared to standard therapy."
Commenting on the findings, Dr Alan Worsley from Cancer Research UK, said: "Advanced kidney cancer has been hard to treat for far too long and it has been particularly difficult to find drugs that work after first-line treatment has failed.
"The drugs tested in these two trials both appear to work better than everolimus - one of the options available if the first treatment fails - and with fewer side-effects.
"Cabozantinib, a targeted therapy, and nivolumab, an immunotherapy, fight cancer in very different ways, so making either available for use in the clinic will greatly expand the arsenal for clinicians to treat kidney cancer patients."
Prof Peter Naredi, the scientific co-chair of the Congress, said he was "excited over the advances" and that the results "most likely will be practice-changing".
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Brain Reading Device Helps to Move Legs of Paralysed Man

A paralysed man has regained some control over his legs using a device that reads his brain, scientists say.

Brain waves were interpreted by a computer, which then controlled the electrical stimulation of his human leg muscles. The US study, in the Journal of Neuroengineering and Rehabilitation, showed he was able to walk just under four metres with support. Experts said maintaining balance was an issue that needed to be addressed. A spinal cord injury prevents the flow of messages from the brain. However, the brain is still able to create messages and the legs are still capable of receiving them.
The researchers at the University of California, Irvine, used a brain-computer interface to bypass the damage in a man who had been paralysed for five years.
An electroencephalogram (EEG) cap read the activity of the man's brain and his initial training was to control a virtual person or avatar in a computer game.
'Interesting study'
Electrodes were then placed on leg muscles and the patient began training to move his own legs.
When he thinks of walking then the muscles are simulated to alternately move the right and left legs until he stops thinking about walking.
One of the researchers, Dr An Do, said: "We showed that you can restore intuitive, brain-controlled walking after a complete spinal cord injury.
"This non-invasive system for leg muscle stimulation is a promising method and is an advance of our current brain-controlled systems that use virtual reality or a robotic exoskeleton."
Dr Mark Bacon, from the charity Spinal Research, told the BBC: "This is an interesting early-stage study.
"What makes this interesting is the move out of the virtual realm by activating lower-limb muscles in a walking pattern.
"In that regard they have been successful. However, independent over-ground walking is still some way off, not least because the issue of maintaining balance hasn't yet been addressed."
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Why Alums Are added in Town Water Supply?

Town water consists of suspended particles such as impurities having colloidal dimension when alums are added in such water the ions provided by alums remove the surface charge present in a colloidal impurities so there precipitation occure such precipitation can be easily removed by filtration and the water will be obtained in more pure forms.
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Why Fecl3 Solution is applied in a cut to prevent bleeding?

Blood is colloidal solution which contain impurities of colloidal particles. When Fecl3 is applied in a Cut the ions provided by fecl3 neutralize the charge present in colloidal impurities and precipitation occurs at the surface so Fecl3 solution is applied in a cut to prevent bleeding.
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Friday, September 25, 2015

Chemistry of all Lanthanides is so identical?

All the lanthanides have similar outer electronic confugration and exibit common +3 Oxidation state in their compounds, therefore lanthanides have exceedingly similar chemical properties. Their similarity is much closer than that of ordinary transition elements because lanthanides differ mainly in the number of 4f electrons which are buried deep in the atoms of lanthanides and thus don’t influence their properties. Moreover due to lanthanide contraction there is very small difference in the size of these ions is almost identical which results in similar chemical properties of these elements.


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Can lanthanum (Z=57) ion exist +4 Oxidation state?

Lanthnum(Z=57) has electronics configuration [Xe]5d1 6s2  and forms La3+ ion by the removal of 3 electrons (two electrons from 6s and one electron from 5d) leaving behind stable noval gas configuration. To form  La4+ ion stable noble gas configuration will have to be distributed which is impossible. Hence La4+  Ion cannot exist.
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APPLICATION (USES) OF SILICONES


1. As silicones are water–resistant, they are useful for water-proofing certain industrial materials. The polar Si-O bonds orient themselves near the surface and the organic groups present a water-repelling exterior.
2. They Are used as effective lubricants of very high and low temperature and as hydraulic fluids beacase of their viscous nature and thermal stability.
3. Silicones resins are used in the insulaton of electrical equipments and in electronics for printed circuit bords. They are used for the encapsulation of components such as resistors and intergrated circuit.
4. Highly viscous (Semisolid) silicones enclosed in biologically compatible pouches, are used for breast implant. They have physiological intertness and are thus suitable for such an application.
5. Those with smaller degree of cross linking are rubber like, they are called silicone rubbers. These are used as substituents or natural rubber in some products. They are also used for making gasket, valve seals etc. since it is highly flexible.
6. They are used for making high temperature paints.
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Thursday, September 10, 2015


Solar water-splitting technology developed

Researchers have demonstrated an efficient new way to capture the energy from sunlight and convert it into clean, renewable energy by splitting water molecules. The technology uses sunlight-harvesting gold nanoparticles.

Rice University researchers have demonstrated an efficient new way to capture the energy from sunlight and convert it into clean, renewable energy by splitting water molecules.
Rice University researchers have demonstrated an efficient new way to capture the energy from sunlight and convert it into clean, renewable energy by splitting water molecules.
Credit: I. Thomann/Rice University
The technology, which is described online in the American Chemical Society journal Nano Letters, relies on a configuration of light-activated gold nanoparticles that harvest sunlight and transfer solar energy to highly excited electrons, which scientists sometimes refer to as "hot electrons."
"Hot electrons have the potential to drive very useful chemical reactions, but they decay very rapidly, and people have struggled to harness their energy," said lead researcher Isabell Thomann, assistant professor of electrical and computer engineering and of chemistry and materials science and nanoengineering at Rice. "For example, most of the energy losses in today's best photovoltaic solar panels are the result of hot electrons that cool within a few trillionths of a second and release their energy as wasted heat."
Capturing these high-energy electrons before they cool could allow solar-energy providers to significantly increase their solar-to-electric power-conversion efficiencies and meet a national goal of reducing the cost of solar electricity.
In the light-activated nanoparticles studied by Thomann and colleagues at Rice's Laboratory for Nanophotonics (LANP), light is captured and converted into plasmons, waves of electrons that flow like a fluid across the metal surface of the nanoparticles. Plasmons are high-energy states that are short-lived, but researchers at Rice and elsewhere have found ways to capture plasmonic energy and convert it into useful heat or light. Plasmonic nanoparticles also offer one of the most promising means of harnessing the power of hot electrons, and LANP researchers have made progress toward that goal in several recent studies.
Thomann and her team, graduate students Hossein Robatjazi, Shah Mohammad Bahauddin and Chloe Doiron, created a system that uses the energy from hot electrons to split molecules of water into oxygen and hydrogen. That's important because oxygen and hydrogen are the feedstocks for fuel cells, electrochemical devices that produce electricity cleanly and efficiently.
To use the hot electrons, Thomann's team first had to find a way to separate them from their corresponding "electron holes," the low-energy states that the hot electrons vacated when they received their plasmonic jolt of energy. One reason hot electrons are so short-lived is that they have a strong tendency to release their newfound energy and revert to their low-energy state. The only way to avoid this is to engineer a system where the hot electrons and electron holes are rapidly separated from one another. The standard way for electrical engineers to do this is to drive the hot electrons over an energy barrier that acts like a one-way valve. Thomann said this approach has inherent inefficiencies, but it is attractive to engineers because it uses well-understood technology called Schottky barriers, a tried-and-true component of electrical engineering.
"Because of the inherent inefficiencies, we wanted to find a new approach to the problem," Thomann said. "We took an unconventional approach: Rather than driving off the hot electrons, we designed a system to carry away the electron holes. In effect, our setup acts like a sieve or a membrane. The holes can pass through, but the hot electrons cannot, so they are left available on the surface of the plasmonic nanoparticles."
The setup features three layers of materials. The bottom layer is a thin sheet of shiny aluminum. This layer is covered with a thin coating of transparent nickel-oxide, and scattered atop this is a collection of plasmonic gold nanoparticles -- puck-shaped disks about 10 to 30 nanometers in diameter.
When sunlight hits the discs, either directly or as a reflection from the aluminum, the discs convert the light energy into hot electrons. The aluminum attracts the resulting electron holes and the nickel oxide allows these to pass while also acting as an impervious barrier to the hot electrons, which stay on gold. By laying the sheet of material flat and covering it with water, the researchers allowed the gold nanoparticles to act as catalysts for water splitting. In the current round of experiments, the researchers measured the photocurrent available for water splitting rather than directly measuring the evolved hydrogen and oxygen gases produced by splitting, but Thomann said the results warrant further study.
"Utilizing hot electron solar water-splitting technologies we measured photocurrent efficiencies that were on par with considerably more complicated structures that also use more expensive components," Thomann said. "We are confident that we can optimize our system to significantly improve upon the results we have already seen."Story Source: sciencedaily

 

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