Showing papers by "Vipin Kumar published in 2019"

Fabrication and Characterization of Screen-Printed Cu 2 ZnSnS 4 Films for Photovoltaic Applications

Abstract: Cu2ZnSnS4 (CZTS) is deemed to be one of the most promising photovoltaic materials due to its properties such as tunable band gap energy of 1.4–1.6 eV and an absorption coefficient greater than 104 cm−1. In the present work, CZTS films were deposited onto glass substrate by a less complex and cost efficient screen-printing method and thereafter sintered. The structural, morphological, optical and electrical properties of CZTS films were studied. The x-ray diffraction and Raman studies show that the screen-printed CZTS films were indexed to a single phase kesterite structure. The morphology of the films was examined through scanning electron microscopy. The EDAX analysis indicates the presence of Cu, Zn, Sn, and S elements in the films. Direct type band gap of 1.51 eV was found for the films, which is quite close to the optimum band gap, i.e., between 1.4 eV and 1.5 eV required for a solar absorber layer. The dark electrical resistivity of films was found to be of the order of 102 Ω-cm as evaluated by the two probe method.

Preparation of ZnO thin film using sol-gel dip-coating technique and their characterization for optoelectronic applications

Abstract: ZnO thin film with an aim to employ in opto-electronic applications was prepared using sol-gel dip-coating route and thereafter sintered at temperature 500 oC. The film has been investigated by XRD pattern, SEM, UV-Vis and photoluminescence spectroscopy for physical and optical characterization of ZnO thin film. X-Ray diffraction pattern analysis reveals the polycrystalline nature with hexagonal wurtzite structure having orientation along the plane (002). Scanning electron micrograph shows symmetrical dense ZnO rod throughout the surface. The diffuse reflectance spectrum is studied in the range of wavelength 300-800 nm. A band gap of 3.21 eV is calculated using Kubelka-Munk function. PL spectrum shows strong peak at 380 nm due to oxygen vacancy of ZnO.

High yield cycloaddition of carbon dioxide to epoxides catalyzed by metal–organic frameworks

Abstract: A series of metal–organic frameworks (MOFs) based on trimesic acid (also knows benzene tricarboxylic acid [btc]) have been synthesized by a solvothermal procedure which exhibit excellent catalytic fixation of CO2. Cycloaddition of CO2 to epoxides to produce cyclic carbonates is quite promising. The chemical fixation of CO2 reported here is solvent free and carried out under moderately mild conditions. All the MOFs [Zn-btc (1), Co-btc (2), Ni-btc (3), and Cu-btc (4)] were synthesized under same experimental conditions yet possess different structural and catalytic properties. All the catalysts follow first-order kinetics, and Zn-btc (1) proved to be the most catalytically active catalyst among all, with ∼100% yield with a total turnover number of 18,845 mol−1 and an initial turnover frequency (hour−1) of 946 with respect to the cyclic carbonate. All MOFs (1–4) show almost 100% conversion in these reactions. The same reaction using other metal (Co, Ni, Cu)-btc compounds has also resulted in products with more than 94% yield, creating an extra impact on the importance of the work.

Soil properties, productivity and juice quality of sugarcane through integration of organic and inorganic nutrient sources in calcareous soil

Abstract: The present study was undertaken to assess the magnitude of changes in soil properties and productivity of sugarcane with integration of inorganic (chemical fertilizer) and organic (vermicompost, neem cake and castor cake and biofertilizers) nutrient sources of fertilizer during 2016-18 in calcareous soil. Integration of organic and inorganic nutrient sources showed significant increase in organic carbon and respiration rate of soil after sugarcane harvest. The mean organic carbon (4.28-4.93g kg) and CO2 evolution (9.91-17.10 mg100gm soil day) varied significantly. Increased soil respiration rate indicating higher microbial activity and high rate of decomposition of organic matter in soil. The integrated nutrient management practices was also found effective in improving soil fertility in terms of available NPK content of post-harvest soil over control. The significant improvement in bulk density and porosity were observed with increasing proportion of various organic with inorganic fertilizer. Plant population, number of millable cane, cane length, single cane weight and cane yield were significantly affected due to integrated use of nutrients through inorganic and organic sources. The significantly higher cane yield (83.86t/ha) were recorded in treatment receiving 50% N through inorganics + 50% N through organics (Vermicompost + castor cake + neem cake) 1/3eah along with bio-fertilizer followed by treatment receiving 50% NPK+ 50% N (Vermicompost + castor cake) 1⁄2 each + biofertilizer (78.88 t ha). The juice quality parameters viz. brix, pol, purity and commercial cane sugar percent remains unaffected due to integrated use of organic and inorganic fertilizer however, juice recovery (61.2366.48%) and sugar yield (7.70-9.48 t/ha) varied significantly. Integration of chemical fertilizer with organic nutrient combinations of vermicompost and neem/castor oil cakes along with biofertilizers was more effective for sustainable sugarcane production and maintenance of soil health.

Study on mechanically alloyed tin telluride screen-printed films for optoelectronic device applications

Abstract: Narrow band gap semiconductor tin telluride (SnTe) was synthesized by mechanical alloying and its film was deposited on glass substrates by the economically and commercially feasible screen-printing technique. Deposition of the film was followed by sintering. Different analytical techniques were utilized to study the structure, surface morphology, elemental, optical and electrical characteristics of the film. X-ray diffraction analysis confirms that the film is polycrystalline in nature and exhibits rock salt type structure with preferred orientation of grains along (200) direction. EDAX spectrum confirms the presence of Sn and Te elements in the film. SEM image shows that the film exhibits uniform surface. The energy band gap of the film was determined by reflection spectra. The film is found to have a direct band gap of 0.37 eV. The dark electrical conductivity and activation energy of the film were measured in temperature range 300–380 K. Hall Effect measurement indicates that the film has p-type electrical conductivity.

Morphological, physiological and biochemical analysis of wheat genotypes under drought stress

Abstract: Drought is a common abiotic stress that seriously affects wheat (Triticum aestivum L.) production in many parts of the world, particularly in arid and semi-arid regions. Therefore, maintaining a sufficient yield under drought conditions has become a priority, particularly considering global environmental changes and increase in world population. In present study wheat genotypes were evaluated for different morphological, physiological and biochemical characters under drought stress. Drought conditions were imposed by holding water irrigation for 15 day before flowering stage. Morphological parameter like plant height, leaf area, and number of tillers recorded in the range of 56.8 - 69.3cm, 14.5 - 44.1 cm, 3.4 - 5.2 respectively. Physiological parameter like chlorophyll content, relative water content was recorded in the range of 44.8 to 58.9, 69.3% to 86.6% respectively. Under biochemical parameter, proline content was recorded in the range 0.11 to 0.86 umole/gmfw. All these parameters were greatly affected under imposed drought conditions. Almost all the parameters were showed decline trend under imposed drought conditions except proline content.

Response of Foliar Application of Micronutrients to Reproductive Parameters of Guava (Psidium guajava L.)

Abstract: The Guava is one of the most common and important fruit crop cultivated all over India. It is fourth most important fruit crop in area and production after mango, banana and citrus. It is classified under genus Psidium which contains 150 species, but only Psidium guajava exploited commercially. It was introduced in 17 th century in India by Portuguese people. Guava is hardy, prolific bearer and remunerative fruit. This fruit is considered to be a poor man’s apple because of its high nutritive value and comparatively low price. Guava is rich source of vitamin C, vitamin A, vitamin B2 (Riboflavin) and minerals like calcium, phosphate and iron. The vitamin C content of Guava fruit is 212 International Journal of Current Microbiology and Applied Sciences ISSN: 2319-7706 Volume 8 Number 10 (2019) Journal homepage: http://www.ijcmas.com

Outcome analysis of arthroscopic single bundle anterior cruciate ligament reconstruction through an accessory antero medial portal technique

Abstract: Introduction: Anterior Cruciate Ligament (ACL) injuries are quite common among young sportspersons and those leading an active life, thereby stressing on the need to provide a rehabilitation that provides full functionality and can cut-back the duration of hospital stay in order to enable these persons to contribute actively to the society. As far as the incidence of ACL injuries in general population is concerned, it is one of the most common ligament injuries in sports traumatology. Materials and Methods: This is a comparative prospective study comprising of two groups each having 30 patients with complete ACL tear. In one group Accessory Antero medial portal technique was used and in the other group antero medial portal technique was used. The follow period was 1 year. Patients were assessed clinically and by lysholm knee score. Result: On the basis of this study it was found that patients in short term there is no significant difference between two techniques. However, in mid-term (6 months and 12 months) functional results are better in AAM as compared to AM. Femoral tunnel angles are smaller in AAM as compared to AM. Conclusion: For single bundle ACL reconstruction Accessory antero medial portal technique is a better procedure.

Lightning Strike Damage of CF/Epoxy Composite Laminates with Conductive Polymer Layers

Abstract: Carbon fiber reinforced plastics (CFRPs) are prone to severe damages by lightning strikes due to their low electrical conductivity. Current lightning strike protection (LSP) technology generally consists of metal foils/films on the surface of composite airframe structures. The present work aims to introduce all polymeric conductive layer for LSP of CFRP structures. Intrinsic conductive polymer i.e. Polyaniline (PANI) is used to make a thermosetting polymer mixture. CFRPs coated with this electrically conductive, all polymeric layer was tested against simulated lighting strike. It has been shown that PANI-LSP specimens dissipated the lightning current effectively and provided enough residual mechanical properties of CFRPs.

Effect of different levels of zinc on zinc efficiency for maize genotypes under calcareous soil

Abstract: Twelve maize genotypes viz. Four composites (Laxmi, Swan, Devki and Hemant), four quality protein maize (Shaktiman-1, Shaktiman-2, Shaktiman-3, and Shaktiman-5) and four hybrids (Raja 909, NK 6607, Rasitopless and Rasi 3022) were tested for their response and efficiency to zinc fertilization at Dr. Rajendra Prasad Central Agricultural University Pusa (Samastipur) Bihar. The genotypes were not equally responsive to zinc application. Except composite genotyped all other genotypes (Hybrid and Quality protein maize) showed higher response to zinc application. Among the hybrids the Rasitopless had the highest response followed by Raja 909, NK 6607 and Rasi 3022, the later two having identical responses. Comparing the Quality protein maize their response can be ranked as Shaktiman-5> Shaktiman-1> Shaktiman-3> and Shaktiman-2. The relative grain yield i.e zinc efficiency index varied from 92.5 to 75.5% and relative grain zinc uptake i.e zinc efficiency varied from 77.4 to 44.8% among the genotypes. On the basis of Zinc efficiency, genotypes were classified into efficient and nonresponsive (Raja 909, NK 6607, Rasitopless, Rasi 3022 and Shaktiman-3), efficient and responsive (Shaktiman-1 and Shaktiman-2), inefficient and nonresponsive (Shaktiman-5) and inefficient and responsive (Laxmi, Swan, Devki and Hemant). From a practical point of view genotypes that produce high grain yield at low level of zinc and respond well to zinc additions are the most desirable because they able to express their high yield potential in a wide range of zinc availability.

Fabrication and characterization of Cd0.98Zn0.02O film by inventive sol-gel screen-printing technique

Abstract: In this paper Cd0.98Zn0.02O film was fabricated via sol-gel screen-printing technique on the clean glass substrate. The consequence of Zn doping (2%) on structural and optical properties was analyzed by X-ray diffraction, EDAX, UV-visible spectroscopy and photoluminescence spectra. XRD result exhibits the polycrystalline nature of film. The composition of the film was confirmed through the EDAX analysis. The optical band gap of prepared film was studied by transmittance spectra. Peak near edge emission around 520 nm corresponding to green emission was exhibited by PL spectra of the Cd0.98Zn0.02O film.

Formulation of Taste Masked Orodispersible Tablets of Tramadol Hydrochloride and Comparative In Vitro Dissolution Profile With Market Product

Abstract: In this study a taste masked orodispersible tablets of Tramadol Hydrochloride were prepared and evaluated for comparative in vitro dissolution profile with commercially available market product. The bioequivalence of Test and Reference product of Tramadol Hydrochloride tablets using in vitro multipoint dissolution profile study by UV-Visible spectrophotometry were performed. Dissolution medium were purified water & three different buffer solutions of different pH like pH 1.2 (hydrochloric acid solution), pH 4.5 (acetate buffer solution), and pH 6.8 (phosphate buffer solution). The Test and Reference tablets were also evaluated to general quality test of dispersible tablets like weight variation, hardness, friability, disintegration time or dispersion time water absorption ratio, wetting time and assay. Both Test & Reference product were complied with the official specification for uniformity of weight, friability and disintegration time and Assay. The dissolution profiles showed there are no significant change drug release of Test and Reference product of Tramadol Hydrochloride Tablets. The tablets were further analysed for similarity between the dissolution profile of Test and Reference product through determination of difference factor (f1), similarity factor (f2) by calculating the dissolution results of both Test and Reference product at multi time point after 05, 10, 15, 30, 45 minutes. These results similarity factor shows that the both Test and Reference product tablets in this study were bioequivalent.