Structural characterization of multimetallic nanoparticles

Bimetallic and trimetallic alloy nanoparticles have enhanced catalytic activities due to their unique structural properties. Using in situ time-resolved synchrotron based x-ray diffraction, we investigated the structural properties of nanoscale catalysts undergoing various heat treatments. Thermal treatment brings about changes in particle size, morphology, dispersion of metals on support, alloying, surface electronic properties, etc. First, the mechanisms of coalescence and grain growth in PtNiCo nanoparticles supported on planar silica on silicon were examined in detail in the temperature range 400-900°C. The sintering process in PtNiCo nanoparticles was found to be accompanied by lattice contraction and L10chemical ordering. The mass transport involved in sintering is attributed to grain boundary diffusion and its corresponding activation energy is estimated from the data analysis. ^ Nanoscale alloying and phase transformations in physical mixtures of Pd and Cu ultrafine nanoparticles were also investigated in real time with in situ synchrotron based x-ray diffraction complemented by ex situ high-resolution transmission electron microscopy. PdCu nanoparticles are interesting because they are found to be more efficient as catalysts in ethanol oxidation reaction (EOR) than monometallic Pd catalysts. The combination of metal support interaction and reactive/non-reactive environment was found to determine the thermal evolution and ultimate structure of this binary system. The composition of the as prepared Pd:Cu mixture in this study was 34% Pd and 66% Cu. At 300°C, the nanoparticles supported on silica and carbon black intermix to form a chemically ordered CsCl-type (B2) alloy phase. The B2 phase transforms into a disordered fcc alloy at higher temperature (\u3e450°C). The alloy nanoparticles supported on silica and carbon black are homogeneous in volume, but evidence was found of Pd surface enrichment. In sharp contrast, when supported on alumina, the two metals segregated at 300°C to produce almost pure fcc Cu and Pd phases. Upon further annealing of the mixture on alumina above 600°C, the two metals interdiffused, forming two distinct disordered alloys of compositions 30% and 90% Pd. The annealing atmosphere also plays a major role in the structural evolution of these bimetallic nanoparticles. The nanoparticles annealed in forming gas are larger than the nanoparticles annealed in helium due to reduction of the surface oxides that promotes coalescence and sintering. ^ The nanoscale composition and structure of alloy catalysts affect heterogeneous catalysis. We also studied Pd:Cu nanoparticle mixtures of different compositions. In Pd:Cu of composition ratio 1:1, ordered B2 phase is formed during annealing at 450C. During the ramped annealing from 450°C to 750°C, the B2 phase transforms into two different alloys, one alloy rich in copper and the other rich in Pd. This structural evolution is different from that of Pd-Cu system in bulk. In the 3:1 composition, the B2 phase dominates in the isothermal anneal at 450C but a disordered alloy fcc phase is also formed. On annealing to 750°C, the disordered fcc phase grows at the expense of the B2 phase. These findings have important applications for the thermal activation of Pd-Cu nanocatalysts for EOR reactions

A Clinical Study on the Role of Homoeopathy in Managing Anxiety Disorders in School Going Children of Kanniyakumari District

AIM OF THE STUDY: The primary aim is to study the effectiveness of Homoeopathic medicines in managing anxiety disorders in school going children of Kanyakumari district. This is also aimed at determining the type of anxiety disorder prevalent in school going children and also the probable causes for it. MATERIALS AND METHODS: The study was conducted in a systematic way so as to achieve the aims and objectives of the study. A sample of 30 cases were selected after proper screening from OPD and rural centers of Sarada Krishna Homoeopathic Medical College and also from different School Health Programs conducted in and around Kanyakumari district. The school going children were screened for anxiety disorders using Screen for child anxiety related emotional disorders (SCARED) tool. Cases identified with anxiety disorders were screened and selected as per the inclusion and exclusion criteria. Data collected were recorded in the pre-structured SKHMC standardized case record. Cases were processed according to the Homoeopathic principles followed by case analysis; evaluation and the totality were constructed. Prescriptions were done with due reference to Repertory, Materia Medica and Organon of Medicine. Potency selection and repetition were done according to the demand of each case. Improvement of each case was assessed using the Screen for child anxiety related emotional disorders (SCARED) tool during the follow up after 3 to 6 months. Over all general well being of the patient were also assessed. Pre and post treatment analysis was done. Observations were recorded, before treatment scores were compared with after treatment scores and paired ‘t’ test was done to study the effectiveness of Homoeopathic medicines in managing anxiety disorders in school going children of Kanyakumari district. RESULT: After the assessment of study, majority of patients belonged to age groups of 6 – 8 years (40%) and 9 – 11 years (20%). Out of the total 30 patients, half were males (50%) and the others were females. The majority of the children belonged to average (46.66%) and above average (43.33%) socio-economic status. In the study, 60% of patients have natal risk factors, 40% have antenatal risk factors, and 20% have stimulating environmental factors and 23.33% patients have developmental delay as probable risk factors. Out of the 40% of antenatal risk factors, 33% of patients have antenatal maternal emotional causes as risk factor. The co – morbidity of anxiety disorders were with attention deficit hyperactivity disorder, epilepsy, intellectual disability, learning disability, attention deficit disorder, oppositional defiant disorder, nocturnal enuresis and cerebral palsy. According to the scoring done using SCARED tool, majority of patients belonging to 26 – 30 score (30%) and 16 – 20 score (26.66%) have higher possibility to have anxiety disorders in school going children. The most common type of anxiety disorders in children was found to be social anxiety disorder (83.33%) and separation anxiety disorder (76.66%). There was overlapping of different type of anxiety in the same patients. According to scoring of individual type of anxiety disorder, 56.66% of them were under 0 – 4 score in panic disorder, 66.66% of them were under 0 -4 score in generalized anxiety disorder, 43.44% of them were under 5 – 8 score in separation anxiety disorder, 46.66% of them were under 9 – 12 score in social anxiety disorder and even though majority of them doesn’t had significant school avoidance, 23.33% had score 2. Homoeopathic medicines seen to be more effective were Calcarea carbonica, Calcarea phosphoric, Phosphorous, Silicea, Natrum muriaticum etc. 9 patients (30%) showed marked improvement, 10 patients (33.33%) showed moderate improvement and 11 patients (36.66%) showed mild improvement. CONCLUSION: Therefore, Homoeopathy is effective in managing anxiety disorders of Kanyakumari district in school going children of Kanyakumari district based on the comparison of before and after treatment in the scores of anxiety disorders

Dimensionality Reduction of Hyperspectral Imagery Using Random Projections

Hyperspectral imagery is often associated with high storage and transmission costs. Dimensionality reduction aims to reduce the time and space complexity of hyperspectral imagery by projecting data into a low-dimensional space such that all the important information in the data is preserved. Dimensionality-reduction methods based on transforms are widely used and give a data-dependent representation that is unfortunately costly to compute. Recently, there has been a growing interest in data-independent representations for dimensionality reduction; of particular prominence are random projections which are attractive due to their computational efficiency and simplicity of implementation. This dissertation concentrates on exploring the realm of computationally fast and efficient random projections by considering projections based on a random Hadamard matrix. These Hadamard-based projections are offered as an alternative to more widely used random projections based on dense Gaussian matrices. Such Hadamard matrices are then coupled with a fast singular value decomposition in order to implement a two-stage dimensionality reduction that marries the computational benefits of the data-independent random projection to the structure-capturing capability of the data-dependent singular value transform. Finally, random projections are applied in conjunction with nonnegative least squares to provide a computationally lightweight methodology for the well-known spectral-unmixing problem. Overall, it is seen that random projections offer a computationally efficient framework for dimensionality reduction that permits hyperspectral-analysis tasks such as unmixing and classification to be conducted in a lower-dimensional space without sacrificing analysis performance while reducing computational costs significantly

The Benthic Macrofaunal Community in Agricultural Ditches in Kole Paddy Fields, Vembanad Kole Wetlands, India

Paddy fields are connected by drainage ditches (channels),that are considered as drivers of biodiversity inagricultural areas. The macrobenthic community structure in agricultural ditches of Kole paddy fields, a part ofthe Ramsar site Vembanad kole wetlands during a complete crop season was analyzed. The macrobenthicfauna belonged to phyla Annelida, Arthropoda and Mollusca and classes Oligochaeta (60.39%), Insecta(39.31%), Mollusca (0.15%) and Hirudinae (0.15%). The class Oligochaeta was represented by Tubificidae,Naididae, Lumbriculidae; Insecta by Diptera, Coleoptera, Odonata; Mollusca by Bivalvia, Gastropoda.Composition of macrobenthos resembled to that of fresh water wetlands and paddy fields. The average numberof macrobenthos was 1475±2064 ind./m2. There was an unusually high abundance in May (5155 ind./m2); butthe environmental parameters remained usual. The abundance of good quality food or some specific, localizedcondition acting on a microscale which could not be recorded in the environmental analysis would haveresulted in the unusual distribution of the fauna. Highest diversity (3.17) and species richness (1.95) wasobserved during May 2011, during the unusual abundance. Predominant functional feeding group wascollector gatherers indicating the abundance of fine organic particulate matter (FPOM) in the substrate. Nosignificant correlation emerged between macrobenthic abundance and environmental parameters

Who Debarred 'you'? : The Idea of “Unqualified” Public in International Film Festival of Kerala

The paper examines the idea of 'unqualified public' in International Film Festival of Kerala, IFFK.  The general notions about the public in IFFK will be described by narrating incidents and tales of hindrances people faced while entering into the above-mentioned space. The criticisms leveled against cinema in the discussions, outside the space, always contributed to number of censures of the Film Festival too, spurring debates centering around who should watch a movie or who should participate in IFFK. A paper that aims to understand the notion of public, in an international festival on films in Kerala, cannot possibly neglect the typical perspectives and publicnotions about movies, especially among a select group of people in Kerala. While unpacking the notions of who these public individuals are and what their opinions on films are, the paper will also raise questions such as: Do films really imagine a homogeneous public, an idea of public without differences? What is the film‟s conception of public sphere? Do films create a new kind of public sphere? Then, what about cinema kottakas and film festivals? The paper takes note of one of the burning controversies in 2014 in the history of IFFK, that each delegate should submit a note on his/her ideas about cinema. Adoor Gopalakrishnan, Malayalam film director had suggested that only those who know English can enjoy all the movies as the Festival includes movies in other languages with subtitles (Ramnath 2014). So I here look at how specifically, language becomes a key factor to determine a 'qualified public' in IFFK, among other factors that aid in the manufacturing of the 'qualified public'. For this study on IFFK the aim would be to focus on  the description and analysis of (unqualified) public in IFFK in relation to the recent controversies, to reveal the multi-layered construction of the 'qualified public'.

Study on the properties of CuSbS₂ and CuSbSeₓS₂₋ₓ thin films for photovoltaic and photodetector applications

The photovoltaic (PV) technology is of great interest in the present scenario owing to renewable energy production from natural resources such as solar light. At present, the PV technology markedly deals with the solar cells based on single crystalline Silicon. However, the production cost involved in the single crystalline Si-based solar cells accelerated the research towards much cheaper materials for a cost-effective technology. In this aspect, thin film solar cells are of great importance especially solar cells based on chalcogenide semiconductors without compromising much in the device performance due to their versatile properties. CuInGaSe2 and CdTe have come up with conversion efficiencies up to 21.7% and 21.5% which is comparable with the highest reported efficiency of 25.6% for a single-crystalline Si-based cell. Nevertheless, the price and inadequacy of In and Ga, as well as the toxicity of Cd, serves as barriers towards their practical applications. The research was then focused on other semiconducting materials having earth-abundant, low cost and non-toxic constituents. Different material systems were studied as a result including the Cubased compounds such as copper zinc tin sulfo selenide (CZTSSe) and copper zinc tin sulfide (CZTS). Due to issues such as complex structural polymorphism and cation stoichiometry of CZTSSe materials also face problems while incorporated as absorber layers in solar cells. Copper antimony sulfide (CuSbS2) is a novel chalcogenide semiconductor featuring suitable chemical and physical properties for being an absorber layer in solar cells as Antimony preserves the same chemistry as that of Indium and Gallium due to the similarities in their oxidation states as well as ionic radii. Additionally, CuSbS2 exhibits an optical band gap of 1.5 eV for direct transition, a high absorption coefficient of 104 cm−1 and Spectroscopic Limited Maximum Efficiency (SLME) of 22.9% which are some characteristic features required for an ideal photovoltaic absorber layer. This material has gained intense attention in the scientific community since it was first introduced by P.K. Nair et al. via heating of Sb2S3 and Cu2S layers. A lot of attempts have been made thereafter towards developing this material through different physical and chemical methods and subsequently integrating the same in PV devices. In the majority of the attempts, the conversion efficiency of the fabricated cells, however, remained very low compared to the present commercial PV technologies. The highest reported efficiency of a CuSbS2 based solar cell up to date is 3.22% where CuSbS2 was spin-coated using its precursor ink. In this thesis, we make a strong effort towards understanding different properties and device performance associated with this material. We used chemical bath deposition to prepare Sb2S3 thin films onto which the Cu layer was evaporated followed by heating to form the ternary CuSbS2 phase. The effects of different Cu thicknesses, heat treatments (rapid thermal processing, conventional vacuum oven annealing or both at different temperatures durations), were studied in detail on the semoconducting properties of CuSbS2 for PV applications. The structure, morphology, chemical composition and optoelectronic properties of the thin film formed at different conditions were analyzed using various characterization techniques such as XRD, Raman, SEM-EDX, XPS, UV-Vis spectroscopy, I-V and photocurrent response measurements. Device applications of the films which showed comparatively better properties were tested by incorporating them in solar cells as absorber layers. The best solar cell based on CuSbS2 showed an efficiency of 0.6% for the substrate p-n configuration, glass/ITO/n-CdS/p-CuSbS2/Ag. To further improve the efficiency, we alloyed CuSbS2 with selenium solid solution to fabricate quaternary CuSbSexS2−X. Our assumptions for alloying it with Se was ground on the fact that incorporation of Se can shift the bandgap of CuSbS2 from 1.5 to 1.2 eV depending on the Se content for much efficient solar light absorption. The champion cell featuring the quaternary CuSbSexS2−X as the absorber displayed a conversion efficiency of 0.91%, higher than the CuSbS2 based cells. In addition to the PV device application, we also explored the capability of the CuSbS2 in optoelectronic applications where it was tested as a photodetector for a wide range of wavelengths. For the first time ever, we found that CuSbS2 has great potential as a photodetector as well owing to its high sensitivity towards detection of different wavelength light. The synthesis procedure, characterizations, and device applications are explained in detail in different chapters of the thesis which can be really useful in understanding the distinct properties of both CuSbS2 and CuSbSexS2−X and towards further optimization to improve the conversion efficiencies where these compounds are used as absorbers

Monitoring Rice Cropping Pattern and Fallows in Central and Western Part of India

India has the largest area under rice cultivation and holds the second position all over the world as it is one of the principal food crops. Rice-fallow croplands areas are those areas where rice is grown during the Kharif growing season (June- October) followed by fallow during Rabi season (November-February). These croplands are not suitable to grow in Rabi season rice due to their high water needs, but are suitable for short season (≤ 3months). According to national statistics there is an increase in the rice areas in Central and Western states of India. The goal of this project is to monitor the rice-fallow cropland areas & mapping the expansion of rice areas. This study is conducted in Central and Western states of India where different rice eco-systems exist. Time series Moderate Resolution Imaging Spectroradiometer (MODIS) 16days Normalized Difference Vegetation Index (NDVI) at 250m spatial resolution and season wise intensive ground survey data was used. We have applied hierarchical classification and Spectral Matching Techniques (SMT) to map rice areas and the fallows there after (rabi-fallows), in Central and Western states of India. And change detection was carried during 2000-2015 and 2010-2015. The resultant rice maps are compared with available national and sub-national level statistics

वेलांचली ओलिगोकीटे पोन्टोड्रिलस बेर्मूडेन्सिस बेड्डार्ड: पेनिआइड झींगे और पोर्टूनिड केकडे में परिपक्वन को प्रेरित करनेवाले अरकिडोनिक अम्ल का शक्य स्रोत

कृपया पूरा लेखा पढ

A study to evaluate prevalence of thrombocytopenia in antenatal patients

Background: Basically, thrombocytopenia is a hemorrhagic disorder that occurs as a result of reduced platelet counts and this study provides a concise over view about the challenges faced with the antenatals who suffer from thrombocytopenia and related issues. it usually results from various etiological factors which demand proper monitoring and timely management for better maternal and Fetal outcomes. this study focuses on the diagnosis of thromobocytopenia and the causes of it and also the effects. Methods: Data are collected from both the antenatal women attending outpatient and inpatient department at obstetrics and gynecology department at Narayana Medical College and Hospital, Nellore with total platelet count less than 1,50,000/ul and then they are followed and the details regarding antenatal complications, intrapartum events and fetal outcome are collected from them. Results: Present study showed that the definite increased risk of preeclampsia, eclampsia, anemia, hypothyroidism, gestational diabetes mellitus, chronic hypertension, overt diabetes, obesity, preterm labor, cesarean section rate, low birth weight babies in elderly primigravidas and anemia, hypothyroidism, preterm labour, low birth babies, NICU admission in teenage primigravidas compared with pregnant in the younger age group. Conclusions: Timely identification and management of the cause of thrombocytopenia is crucial in the antenatal group of women. Most of the cases of thrombocytopenia are incidental findings with asymptomatic patients. Proper diagnosis and timely interventions are essential for better outcomes in antenatals with thrombocytopenia. gestational thrombocytopenia appears to be the most prevalent causes