CFD simulation using FLUENT and RANS3D - A validation exercise

The present work involves two-dimensional numerical simulation of three benchmark problems like (i) Laminar flow in a lid driven cavity (ii) Turbulent flow past a backward facing step and (iii) turbulent flow past NACA0012 aerofoil, using in-house flow solution code RANS3D and the commercially available FLUENT code. The results obtained using these codes are compared with the available measurement data and/or other computations

Ultrafast photoinduced enhancement of nonlinear optical response in 15-atom gold clusters on indium tin oxide conducting film

We show that the third order optical nonlinearity of 15-atom gold clusters is significantly enhanced when in contact with indium tin oxide (ITO) conducting film. Open and close aperture z-scan experiments together with non-degenerate pump-probe differential transmission experiments were done using 80 fs laser pulses centered at 395 nm and 790 nm on gold clusters encased inside cyclodextrin cavities. We show that two photon absorption coefficient is enhanced by an order of magnitude as compared to that when the clusters are on pristine glass plate. The enhancement for the nonlinear optical refraction coefficient is ~3 times. The photo-induced excited state absorption using pump-probe experiments at pump wavelength of 395 nm and probe at 790 nm also show an enhancement by an order of magnitude. These results attributed to the excited state energy transfer in the coupled gold cluster-ITO system are different from the enhancement seen so far in charge donor-acceptor complexes and nanoparticle-conjugate polymer composites.Comment: To appear in Optics Express (2013); http://dx.doi.org/10.1364/OE.21.00848

Teachers Attitude towards Continuous and Comprehensive Evaluation

Continuous and Comprehensive Evaluation (CCE) refers to a system of school-based evaluation of students that covers all aspects of student's development. CCE is the buzz word being in the air since the talks of the examination reforms being given utmost importance as far as the Indian education system is concerned ( Aggarwal, M. 2004). As rightly quoted by University Education Commission (1948-49) that, “If we are to suggest a single reform in the system of education then it would be that of examination”. The remark was followed by formation of number of committees and commissions with different recommendations for the evaluation system for the Indian education system. All intelligentsia converged to the CCE as an assessment tool for holistic evaluation of the students' learnin

Construction and Standardization of Opinionnaire on You Tube for Teaching-Learning

YouTube is a video-sharing website, created by Chad Hurley, Steve Chen, and Kari, a former PayPal employees in February 2005, on which users can upload, view and share videos. The company is based in San Bruno, California, and uses Adobe Flash Video and HTML5 technology to display a wide variety of user-generated video content, including movie clips, TV clips, and music videos, as well as amateur content such as video blogging and short original videos. Most of the content on YouTube has been uploaded by individuals, although media corporations including CBS, the BBC, VEVO, Hulu, and other organizations offer some of their material via the site, as part of the YouTube partnership program. Unregistered users can watch videos, while registered users can upload an unlimited number of videos. Videos considered to contain offensive content are available only to registered users at least 18 years old. In November 2006, YouTube, LLC was bought by Google for US$1.65 billion, and now operates as a subsidiary of Google

Noble metal nanoparticles for water purification: a critical review

Water is one of the essential enablers of life on earth. Beginning with the origin of the earliest form of life in seawater, it has been central to the evolution of human civilizations. Noble metals have been similarly associated with the prosperity of human civilizations through their prominent use in jewellery and medical applications. The most important reason for the use of noble metals is the minimal reactivity at the bulk scale, which can be explained by a number of concepts such as electrochemical potential, relativisitic contraction, molecular orbital theory, etc. Recently, water quality has been associated with the development index of society. A number of chemical and biological contaminants have endangered the quality of drinking water. An overview of important events during last 200 years in the area of drinking water purification is presented. Realizing the molecular nature of contamination in drinking water, significant progress has been made to utilize the chemistry of nanomaterials for water purification. This article summarizes recent efforts in the area of noble metal nanoparticle synthesis and the origin of their reactivity at the nanoscale. The application of noble metal nanoparticle based chemistry for drinking water purification is summarized for three major types of contaminants: halogenated organics including pesticides, heavy metals and microorganisms. Recent efforts for the removal, as well as ultralow concentration detection of such species, using noble metal nanoparticles are summarized. Important challenges during the commercialization of nano-based products are highlighted through a case study of pesticide removal using noble metal nanoparticles. Recent efforts in drinking water purification using other forms of nanomaterials are also summarized. The article concludes with recent investigations on the issue of nanotoxicity and its implications for the future

A study of research designs adopted and dissemination of research findings by faculty of post graduate department of education

In India, according to the regulations of University Grants Commission (UGC), A national body of Ministry of Human Resource Development (MHRD). The functions of P.G faculty are categorized in three areas namely Teaching, Research and Extension. How ever it is a common notion that P.G.feculty engage most of their time in teaching, then in Research activities. Since Research Designs investigates the process of designing in many fields, a primary interpretation of Research Designs is concerned with undertaking research into the design process. It Challenges the growing advocacy of systematic methods of problem solving. Dissemination methods help to circulate: Scatter; disperse: spread: distribute the principles, ideas and opinion o f the subject for widespread discussion and debate. It also enhances the knowledge sharing among the individuals in the society to know the outcomes of the Research work and the findings. "Research" Research is an examination of the relationship between one or more independent variables and one or more dependent variables. In even more precise terms, we can define research as an examination of the effects of one or more independent variables on one or more dependent variables. Educational research refers to a systematic attempt to gain a better understanding of the educational process, generally with a view to improving its efficiency. It is an application of scientific method to the study of educational problems. Research Design can be thought of as the structure of Research—it is the "glue" that holds all of the elements in a research project together. We often describe using a concise notation that enables us to summarize a complex design structure efficiently

Million frames per second infrared imaging system

An infrared imaging system has been developed for measuring the temperature increase during the dynamic deformation of materials. The system consists of an 8×8 HgCdTe focal plane array, each with its own preamplifier. Outputs from the 64 detector/preamplifiers are digitized using a row-parallel scheme. In this approach, all 64 signals are simultaneously acquired and held using a bank of track and hold amplifiers. An array of eight 8:1 multiplexers then routes the signals to eight 10 MHz digitizers, acquiring data from each row of detectors in parallel. The maximum rate is one million frames per second. A fully reflective lens system was developed, consisting of two Schwarszchild objectives operating at infinite conjugation ratio. The ratio of the focal lengths of the objectives determines the lens magnification. The system has been used to image the distribution of temperature rise near the tip of a notch in a high strength steel sample (C-300) subjected to impact loading by a drop weight testing machine. The results show temperature rises at the crack tip up to around 70 K. Localization of temperature, and hence, of deformation into "U" shaped zones emanating from the notch tip is clearly seen, as is the onset of crack propagation

Structural transformation in formic acid on ultra cold ice surfaces

We have investigated the effect of ice substrate on the temperature dependent structural changes of formic acid. Infrared spectra of HCOOH@KBr, HCOOH@H2Oamorphous and HCOOH@H2Ocrystalline were measured in the temperature range of 18-180 K (X@Y represents X deposited on Y). At 18 K formic acid deposited over ice exists principally as its dimer. Upon increase of temperature, the dimer gets converted to the polymeric crystalline form. In the case of amorphous ice surface, this conversion starts at a lower temperature of 37 K. For KBr and crystalline ice surfaces, this occurs at 98 and 83 K, respectively. The dangling -OH found on amorphous ice surfaces disappears completely upon formic acid deposition. The greater mobility of formic acid molecules on amorphous ice aids in the early onset of its crystallization

Structure and dynamics of monolayers on planar and cluster surfaces

Organized molecular assemblies have been one of the intensely pursued areas of contemporary chemistry. Among the various methodologies used to make organized monolayer structures, self-assembled monolayers (SAMs) have been attractive to many materials chemists owing to the simplicity of the preparative method and high stability. Advances in various techniques and their application in the study of SAMs have significantly improved our understanding of these molecular systems. These studies have been further intensified since the successful preparation of stable metal clusters protected with monolayers. This article reviews the structure, temperature-induced phase transitions, and associated dynamics of monolayers, principally in the context of our own work in this area. Alkanethiols on Au(111) and Ag(111) are taken as archetypal systems to discuss the properties of 2D SAMs; studies from our laboratory have been on evaporated thin films. Alkanethiols on Au and Ag cluster surfaces are taken as examples of 3D SAMs. Although our principal focus will be on alkanethiols, we will touch upon a few other adsorbate systems as well

An investigation of the structure and properties of layered copper thiolates

Copper(I) n-alkane thiolate systems have been characterized using powder X-ray diffraction, IR spectroscopy, X-ray photoelectron spectroscopy and thermal analyses. The diffraction pattern is composed of a series of peaks, which are indexed to (0k0) reflections of a layered structure. The tilt angle, θ, of the alkyl chains is estimated to be 13°, distinctly different from the silver thiolates, where the chains are near normal to the silver plane. The layers interpenetrate to a small (or negligible) extent. The alkyl chain assembly is different from that of crystalline alkanes. An increase in the alkyl chain order with increase in chain length is evident in the infrared spectra. The chains are essentially all-trans, but gauche conformations are seen near the sulfur end. Upon cooling, an orientational transition occurs resulting in the freezing of the local symmetry around the methyl group. The materials show high thermal stability and desorption is seen only above 500 K. High temperature phase transitions of the materials have been studied by variable temperature powder XRD, variable temperature IR and differential scanning calorimetry. Two distinct transitions; one from an original gauche-trans (g-t) to a gauche (g) phase and another subsequent one, to a columnar mesophase, have been identified. The transitions are not fully reversible, conformational changes are observed upon heating and cooling. Thiolates appear to be model systems for the investigation of molecular self-assembly on copper surfaces