00:00 00:00 spaceplay / pause qunload | stop ffullscreenshift + ←→slower / faster ↑↓volume mmute ←→seek . seek to previous 12… 6 seek to 10%, 20% … 60% XColor SettingsAaAaAaAaTextBackgroundOpacity SettingsTextOpaqueSemi-TransparentBackgroundSemi-TransparentOpaqueTransparentFont SettingsSize||TypeSerif MonospaceSerifSans Serif MonospaceSans SerifCasualCursiveSmallCapsResetSave SettingsA nationally renowned forensic pathologist testified Monday in the wrongful death lawsuit brought by the family of Rebecca Zahau.Zahau is the woman who was found bound, gagged and hanging naked from a balcony of the Spreckels mansion in Coronado in 2011.Dr. Cyril Wecht performed a second autopsy on Zahau’s body, about three months after an initial autopsy by the San Diego County Medical Examiner’s office.Wecht said that in his opinion, the young woman’s death was not a suicide.KUSI’s Sasha Foo reports on some of the testimony heard in San Diego County Superior Court. March 12, 2018 Sasha Foo, Pathologist testifies that Rebecca Zahau’s death was a homicide Sasha Foo Categories: Local San Diego News Tags: Coronado, Dr. Cyril Wecht, Rebecca Zahau FacebookTwitter Updated: 10:27 PM Posted: March 12, 2018
Citation: Energetics of the adsorption of ethanol on calcite nanoparticles (2015, April 21) retrieved 18 August 2019 from https://phys.org/news/2015-04-energetics-adsorption-ethanol-calcite-nanoparticles.html Journal information: Proceedings of the National Academy of Sciences Credit: Ben Mills via Wikimedia Commons Nanoparticles have a high surface energy in which organic molecules readily self-assemble on their surface. When organic or biological molecules self-assemble on a nanoparticle, they will often form a type of shell that has its own unique shape and properties. This shell can mask the nanoparticle, changing an inorganic compound, like calcite, into a hydrophobic particle. It also protects the nanoparticle from its environmental surroundings. This is known as organic ligand capping.Prior research has shown that ethanol adsorbs onto calcite by first forming a self-assembled monolayer on the surface in which the hydroxyl group is anchored to the calcite and the hydrophobic tail is oriented outward, forming an organic ligand cap. There is evidence that a second ethanol layer forms, interacting with the hydrophobic tails of the first layer, but there is little quantitative evidence for this two-layer process. This study is the first to report the thermodynamic energetics of these interactions.Wu and Navrotsky accomplish these measurements using direct gas adsorption calorimetry, a technique that was first developed in Navrotsky’s lab. For this study, they used ethanol vapor and four nanocalcite samples of varying particle size.Graphical display of the number of molecules adsorbed as pressure increases shows that the ethanol-calcite system for each type of calcite are type I isotherms. This means that there is an initial adsorption process (chemisorption) that is energetically favored. The differential enthalpy of adsorption per number of ethanol molecules per surface area of calcite (nm2) indicates that the initial interaction of ethanol with the clean surface is the most exothermic (-121.2 +/- 2.4 kJ/mol ethanol) followed by a significantly less exothermic process for the second layer of ethanol molecules. The shape of this enthalpy curve has two distinct plateaus. The first is the initial adsorption of ethanol onto a clean calcite surface, which terminates at about 3.5 ethanol molecules at an enthalpy of 98.3 +/- 4.8 kJ/mol ethanol, in close agreement with theoretical models. Then there is evidence of weak intermediate chemisorption followed by another, less exothermic interaction at the second plateau, at a value less than the condensation of ethanol, which is −42.3 kJ/mol, at 25 °C. The second plateau is likely due to a second, less ordered layer interacting with the hydrophobic ends of the ordered monolayer. Explore further (Phys.org)—Biomineralization, oil recovery, textiles, and catalysis all rely on organic-inorganic interactions with calcite, the most common polymorph of CaCO3. Over the last five years, there has been substantial research discussing qualitative properties of organics adsorbed onto calcite, but little by way of quantitatively determining the thermodynamic interaction between an organic adsorbate and calcite. Di Wu and Alexandra Navrotsky of the University of California, Davis investigated the thermodynamics of ethanol adsorption onto various calcite nanoparticles in an effort to elucidate the organic-inorganic interface and find general properties that could apply to more complex systems. Their work appears in the Proceedings of the National Academy of Science. Microbe produces ethanol from switchgrass without pretreatment Prior research suggests that there is a spatially thin gap with low ethanol density between the first adsorbed monolayer and the bulk alcohol. Wu and Navrotsky’s thermodynamic data support this model, and suggests that the newly formed hydrophobic nanoparticle may induce short-range order in the bulk solution up to 2 nm beyond the surface of the nanoparticle.In experiments comparing adsorption of ethanol on calcite versus water on calcite, both ethanol and water show an initial, highly exothermic interaction. Both have hydroxyl groups available to adsorb onto calcite, making it reasonable to assume that the initial adsorption onto clean calcite would be similar for both. After this first phase, both become less exothermic; however, ethanol will display a second plateau, providing a step-wise curve, while the curve for water shows only one gradual inflection. Additionally, entropy and free energy calculations for both water and ethanol showed a similarly shaped curve as the enthalpy graphs, and both became less negative as more molecules were adsorbed. However, ethanol preferentially binds to the calcite at low partial pressures, which is likely due to entropy effects.These experiments reveal uniformity among the different types of calcite. Despite differences in size and surface area, they apparently have energetically similar binding sites. All showed a strong initial adsorption followed by evidence of a thin gap and a less ordered layer, and suggests that this type of interaction could be generalized for more complex organic molecules, such as proteins, on a calcite nanoparticle surface. Furthermore, the tight capping of organic ligands may serve as a protective barrier to the nanoparticle core. Aside from providing insight into biological systems, researchers may be able to exploit these properties to make nanoscale devices. This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. © 2015 Phys.org More information: “Probing the energetics of organic-nanoparticle interactions of ethanol on calcite” Di Wu and Alexandra Navrotsky, PNAS, www.pnas.org/content/early/2015/04/08/1505874112AbstractKnowing the nature of interactions between small organic molecules and surfaces of nanoparticles (NP) is crucial for fundamental understanding of natural phenomena and engineering processes. Herein, we report direct adsorption enthalpy measurement of ethanol on a series of calcite nanocrystals, with the aim of mimicking organic–NP interactions in various environments. The energetics suggests a spectrum of adsorption events as a function of coverage: strongest initial chemisorption on active sites on fresh calcite surfaces, followed by major chemical binding to form an ethanol monolayer and, subsequently, very weak, near-zero energy, physisorption. These thermochemical observations directly support a structure where the ethanol monolayer is bonded to the calcite surface through its polar hydroxyl group, leaving the hydrophobic ends of the ethanol molecules to interact only weakly with the next layer of adsorbing ethanol and resulting in a spatial gap with low ethanol density between the monolayer and subsequent added ethanol molecules, as predicted by molecular dynamics and density functional calculations. Such an ordered assembly of ethanol on calcite NP is analogous to, although less strongly bonded than, a capping layer of organics intentionally introduced during NP synthesis, and suggests a continuous variation of surface structure depending on molecular chemistry, ranging from largely disordered surface layers to ordered layers that nevertheless are mobile and can rearrange or be displaced by other molecules to strongly bonded immobile organic capping layers. These differences in surface structure will affect chemical reactions, including the further nucleation and growth of nanocrystals on organic ligand-capped surfaces.
Nuanced rhythms of India and Africa power the sounds of Swiss jazz giant Malcolm Braff’s contemporary compositions that address the musical concerns of the world rather than the niche musical stage of traditional jazz that grew out of America.Braff, described as one of Switzerland’s best contemporary jazz pianist, was in India with his band, the Malcolm Braff Trio, at the International Jazz Festival in the capital presented by the Indian Council of Cultural Relations (ICCR). Also Read – ‘Playing Jojo was emotionally exhausting’He played a fusion recital with bassist Reggie Washington and percussionist Stephane Galland from a repertoire of new European arrangements with global sounds.‘I came to India for the first time in 2005 with French-Swiss contemporary jazz maestro Erik Truffaz as a trumpet player. He was touring India. In every city that we visited, we invited local classical musicians to join us,’ Braff said. The local collaborations led to fusion performances, most of which were impromtu. Also Read – Leslie doing new comedy special with NetflixIt was the beginning of the 42-year-old musician’s engagement with Indian music. ‘While we were playing in Kolkata, we met an upcoming musician duo – Indrani and Apurva Mukherjee – and played their songs with them,’ Braff recalled.The concert later matured into a project when the band returned to Kolkata after two years in 2007 and spent a month rehearsing with them. ‘We created an album of western jazz improvisations with Indian classical music,’ he said. It was not really fusion as the way people understood fusion here, Braff said.‘We were trying to merge two traditions so that they could retain their identities,’ the musician said. The album was special to Braff because ‘there was no bass’.Indian tabla and African rhythms – especially the influences of Abdullah Ibrahim’s Africa and Zulu gospel – creep into Braff’s compositions in subtle ways.‘I am inspired by what I perceived as a child travelling around the world. I was born in Brazil and moved to Africa at the age of two. I spent my childhood in Cape Verde and Senegal,’ he said. Braff says he cannot pretend to be bringing ‘African rhythm directly in my music, but it comes in unconsciously’.Jazz has, over the years, evolved into distinct genres to become ‘Indian, American and European. I don’t really know Indian jazz really well, but I think about musicians applying jazz attitude to their music to express differently and improvise’.
Kolkata: IIT Kharagpur is willing to work with the Bengal government on its Kanyashree project and provide technological upgradation for further enhancement of the quality of learning for girls.”We have developed National Digital Library of India (NDLI) where all types of books are available in a single platform. If we can integrate this digital library with the Kanyashree project, we will be able to assess the progress of education of girls and accordingly provide them with the correct input to enhance their education level,” IIT Kharagpur director Dr Partha Pratim Chakrabarti said. Also Read – Heavy rain hits traffic, flightsHe further maintained that IIT KGP has come up with a research centre for Artificial Intelligence (AI) on its Kharagpur campus and is coming up with another centre for emerging technologies like AI, Internet of Things (IoT) and Machine Learning at Rajarhat.”Emerging technologies like AI can be used in Kanyashree project and this will improve learning, hence, contribute to the development of a girl child in the real sense of the term. We want to contribute in a big way to this development so we are looking forward to work with the Bengal government,” Chakrabarti said. Also Read – Speeding Jaguar crashes into Merc, 2 B’deshi bystanders killedThe project, which was rolled out in March 2013, presently has 4,84,8970 beneficiaries. IIT Kharagpur had once extended their help when there was a problem in the smooth functioning of the project.Kanyashree is the pet project of Chief Minister Mamata Banerjee for the upliftment of girls from the poor families and enables them to pursue higher studies, which they are unable to do due to economic constraints. It is a targeted conditional cash transfer scheme aimed at retaining girls in schools and other educational institutions. It also aims towards skill development and prevent child marriage. The United Nations in June last year awarded the Bengal government for its “Kanyashree” scheme.The project won the first place for Public Service at the World Forum out of a total of 552 projects from 62 countries, which were nominated for the award.
What/who inspired you to write the book? Please quote personal instances, if any. Parliament of India has almost an infinite canvas to work on, domestically and internationally. While, what it does within its magnificent red stone building always gets much talked about, little is known of its performance in the international arena. Many people do not know that our Parliament, which is the nerve centre of the largest democracy in the world, is highly admired by other Parliaments. I have personal experience of many speakers, including those of advanced countries, coming to me to enquire what stand I was taking on a particular issue or who I was voting for so that they could do the same. Also Read – ‘Playing Jojo was emotionally exhausting’Although, our Parliamentary system is based on the Westminster model of U.K, yet over the years it has evolved so much that speakers of several Commonwealth counties have told me that in a difficult situation they invariably study the rulings given by the Indian speakers to find a solution. Such is the stature of our Speaker and our Parliament. Needless-to-say, a great deal of hard work goes into achieving and maintaining this position of eminence. I therefore felt the need to write this book and give a glimpse of how it is done. Also Read – Leslie doing new comedy special with NetflixHow do you define Parliamentary diplomacy? What role does it play in improving foreign relations?Parliamentary diplomacy is the fine art of a parliament engaging fruitfully with other parliaments. It has come of age the world over. In India too it is increasingly becoming an effective instrument of state craft. It is conducted by the Speaker who represents our Parliament in bilateral and multilateral forums, accompanied by members of Lok Sabha and Rajya Sabha. The discussions are not only on parliamentary affairs but also, in fact and more, on bilateral, regional and global issues. It is a parallel function of the Speaker to strengthen our relationship with the world. The foreign policy pronouncements of our Speaker are the same as that of the Prime Minister, but the style and channels used are different. Parliamentary diplomacy, on its own, has the potential to generate abundant international goodwill. Do you think our Parliamentarian have broader understating of global concerns?Yes. The Constitution of India has empowered our Parliament to enact laws regarding our relation with any foreign country. Our parliamentarians therefore, have to be aware all the time, of international developments. Personally, I find that many of our members have a sound knowledge of the intricacies of foreign affairs.The decorum in the Indian Parliament is generally questioned by many. As a former speaker, don’t you think there needs to be some sort of moral conduct while discussing important issues like terrorism, internal security etc?There are rules in this regard but rules cannot always be effective. Member of Lok Sabha are elected representatives and, I am sure, most of them would want to get re-elected. Since the proceedings of the House are directly telecast, it is most likely that the members would do what their voters want. In my view, the demand for decorum, to be effective, should also come from the voters.Shouldn’t there be healthy meeting of minds when it comes to dealing with such important issues?Parliament of India has many beautiful traditions. One of them is that the political parties or independent members in both the Houses of Parliament never ever differ on foreign policy. This key institution of our polity firmly projects its view of the world in one voice.As the first women speaker of India and as an ex- IFS, how do you think India fares globally?As the first women Speaker of India I attended the 6th conference of the women speakers of the world in Berne and hosted the 7th conference in our Parliament. My interactions in a forum where my predecessors could not participate had its benefits. However, the fact remains that the work of a speaker is gender neutral. As a former foreign service officer who has worked at many levels to formulate the foreign policy, I think India commands respect globally and the Parliament is definitely looked up to.Beyond being an avenue for discussion, such networks can have a long-term impact on the avoidance of conflict. Do you agree?Certainly. Democracy and democratic temper always help in minimising conflict. Power of the ballot is far more than that of the bullet. Our commitment, tenacity and enduring faith in the sublime process of democracy contribute in no small measure to conflict avoidance and world peace.
Is Snapchat’s co-founder crazy for not taking $3 billion?Crazy doesn’t begin to describe how nutty this is. He’ll never see that kind of dough again.Uh, hello. Would you want to work with Mark Zuckerberg?Snapchat is the next big thing. He’s smart for holding out for a better offer.He comes from a privileged family. He doesn’t need the money anyway.I say Evan Spiegel is crazy smart. He clearly has a bigger vision for Snapchat.VoteView ResultsCrowdsignal.comIs Snapchat’s co-founder crazy for not taking $3 billion? Free Webinar | Sept. 9: The Entrepreneur’s Playbook for Going Global November 14, 2013 The internet has been a-buzz since news broke yesterday that 23-year-old Evan Spiegel, the co-founder and chief executive of messaging service Snapchat, turned down a $3 billion offer to be acquired by Facebook.Three billion dollars ain’t chump change. Especially for an app that so far isn’t generating revenue.So is Spiegel crazy or crazy smart for not taking all that money? Let us know what you think by taking the poll below.Related: This Is the 23-Year-Old Entrepreneur Who Just Turned Down $3 Billion From Facebook 1 min read Growing a business sometimes requires thinking outside the box. Register Now »