Papers by Purushottam Kumar
Role of defect density in absorber layer of ternary chalcogenide Cu2SnS3 solar cell
Optical Materials, 2021
Abstract Ternary Chalcogenide Cu2SnS3 (CTS) has emerged as a potential candidate for light absorb... more Abstract Ternary Chalcogenide Cu2SnS3 (CTS) has emerged as a potential candidate for light absorbing material for photovoltaic solar cells owing to its tuneable bandgap, abundance in earth's crust and low toxicity. The PV performance of CTS solar cells has been assessed using Solar Cell Capacitance Simulator (SCAPS-1D) in the present study. The influence of defects in ascertaining the CTS solar cells' photovoltaic performance has been described. The impact of various type of defects and their density on Voc, Jsc, FF and η has been evaluated. Change in energy band diagrams due to change in defect density has been analysed. Quantum Efficiency curves for different defect densities in CTS solar cells have been investigated. The increment in defect density in the CTS absorber has been found to degrade CTS solar cell performance regardless of the type of defect.
Introduction Techniques for Panicum maximum L. and Sataria anceps S. Grasses in a Natural Grassland
A theoretical study on the stability of the classical phases of surfactant-water systems in the temperature-concentration phase diagram
Molecular Crystals and Liquid Crystals, 2021
In the present study, we have used a mean field theory that is also a modified Ginzburg-Landau ex... more In the present study, we have used a mean field theory that is also a modified Ginzburg-Landau expansion in the order parameter. Single mode expansion of the order parameter were taken and written ...
A novel similarity measure for the link prediction in unipartite and bipartite networks
Social Network Analysis and Mining, 2021
Networks are everywhere and their applications in various fields such as computer science, biolog... more Networks are everywhere and their applications in various fields such as computer science, biological science, economics, and chemical engineering attracted attention of many researchers. Many complex systems in the real world can be represented by networks or graphs. Link prediction is one of the most important tasks in network analysis, thus attracting tremendous research interests in the last decades. In this paper, we present a novel algorithm for link prediction that works efficiently for both unipartite graphs and bipartite graphs. Our novel algorithm is based on the concept of eigenvectors and shortest distance between the nodes. We used the Peron–Frobenius theorem of node importance for link prediction. Four metrics, namely AUC, precision, prediction-power, and precision@K, were computed and compared with fourteen baseline algorithms to test the performance of the proposed algorithm. Testing was done on the thirteen datasets, and experimental results show that the proposed method outperforms the baseline algorithm on the basis of four given metrics.
Renewable Energy, 2020
In the present work, a hydroelectric cell (HEC) is fabricated to generate the electricity through... more In the present work, a hydroelectric cell (HEC) is fabricated to generate the electricity through the splitting of water into H 3 O þ and OH À ions without releasing any toxic by-product. Nanoporous Fe 3 O 4 and Li-doped Fe 3 O 4 materials have been synthesized by facile chemical co-precipitation method. BET (Bru-nauereEmmetteTeller theory) results exhibited surface area of Li-doped Fe 3 O 4 to be 45 m 2 /g with pore radius~4 nm. The obtained powder was pressed into pellets of 4.08 cm 2 area. Then, Zn electrode was attached at one face of each pellet and silver on the opposite face to fabricate the hydroelectric cells. Cyclic Voltammetry (CV) curve of HEC demonstrates cathodic and anodic peak corresponding to a redox reaction at Zn and silver electrodes. The fabricated HEC of 4.08 cm 2 area of Li-doped Fe 3 O 4 delivers short circuit current, open-circuit voltage and off-load output power as 44.91 mA, 0.68 V, 30.80 mW, respectively. Ionic diffusion of the dissociated H 3 O þ and OH À ions have been confirmed by Nyquist curves of both HEC's compared to a dry state. The off-load 30.80 mW output power generation through Li-doped Fe 3 O 4 based Hydroelectric Cell of 4.08 cm 2 area is significant and has emerged as a viable alternative to other green energy sources.
ACS Omega, 2020
The generation of electricity by dissociating water into H 3 O + and OH − ions through a hydroele... more The generation of electricity by dissociating water into H 3 O + and OH − ions through a hydroelectric cell (HEC) without liberating any toxic waste has achieved a groundbreaking feat. Nanoporous magnesium-doped SnO 2 and cobalt-doped SnO 2 materials have been prepared via a novel sol−gel method. The X-ray diffraction patterns of Mg-doped SnO 2 and Co-doped SnO 2 completely match with those of pure SnO 2 , which confirms the interstitial substitution of Mg and Co in the pristine SnO 2. The results shown by Brunauer−Emmett−Teller theory curves illustrate the surface area of Mg-doped SnO 2 and Co-doped SnO 2 to be 46.22 and 46.81 m 2 /g, respectively, with their pore radii being ∼3 nm. The synthesized nanoparticles were pressed into square pellets of area 4.08 cm 2. A zinc electrode was pasted on one side of each pellet and silver was painted on the other side to develop the HECs. The fabricated HECs of Mg-doped SnO 2 and Co-doped SnO 2 with 4.08 cm 2 area deliver short-circuit current, open-circuit voltage, and off-load output power of 41.69 mA, 0.787 V, and 32.81 mW and 77.52 mA, 0.454 V, and 35.19 mW, respectively. Cyclic voltammetry of both materials exhibited cathodic and anodic peaks in relation to the redox reactions taking place at Zn and silver electrodes. Nyquist curves of both HECs in the wet state confirm the ionic diffusion of split H 3 O + and OH − ions as compared to the dry state. An off-load output power of 35.19 mW delivered by the HEC of Co-doped SnO 2 with 4.08 cm 2 area is quite promising and has great potential to replace other green energy sources.
Sensors, 2020
In the present study, we assessed for the first time the performance of our custom-designed low-c... more In the present study, we assessed for the first time the performance of our custom-designed low-cost Particulate Matter (PM) monitoring devices (Atmos) in measuring PM10 concentrations. We examined the ambient PM10 levels during an intense measurement campaign at two sites in the Delhi National Capital Region (NCR), India. In this study, we validated the un-calibrated Atmos for measuring ambient PM10 concentrations at highly polluted monitoring sites. PM10 concentration from Atmos, containing laser scattering-based Plantower PM sensor, was comparable with that measured from research-grade scanning mobility particle sizers (SMPS) in combination with optical particle sizers (OPS) and aerodynamic particle sizers (APS). The un-calibrated sensors often provided accurate PM10 measurements, particularly in capturing real-time hourly concentrations variations. Quantile–Quantile plots (QQ-plots) for data collected during the selected deployment period showed positively skewed PM10 datasets. ...
The current indian epidemic of dermatophytosis: A study on causative agents and sensitivity patterns
Indian Journal of Dermatology, 2020
Background: In the recent years, the frequency, severity, clinical characteristics, treatment res... more Background: In the recent years, the frequency, severity, clinical characteristics, treatment response, and relapse rate of dermatophytosis have dramatically changed in India. Given the surge in dermatophytosis, we had undertaken a study to isolate and identify the common species causing dermatophyte infection and to know the in vitro efficacy of the common antifungals against them. Materials and Methods: total of 103 new cases that were not on any treatment for the past 3 months were included. Skin scrapings were collected for direct microscopic examination and for fungal culture in Sabouraud 4% dextrose agar (SDA) with chloramphenicol and cycloheximide slant tubes, and dermatophyte test media. Fungi were identified on the basis of their macroscopic and microscopic features with the help of lactophenol cotton blue staining and urease test. Also, the drug sensitivity of the dermatophytes was tested with the common antifungals. Results: Of the 55 cases (53.4%) that were positive for dermatophytes in the culture, 29 showed possible contamination. Trichophyton was the predominant organism (49 cases) with T. verrucosum being the commonest species (26 cases), followed by T. rubrum (15 patients), and T. mentagrophytes(8 cases). All species of Trichophyton were found to be most sensitive to itraconazole amongst systemic antifungals and luliconazole amongst topical antifungals. Conclusion: This study concluded that the causative agent for the dermatophytosis was changing in India and in our subset, T. verrucosum caused the maximum number of infections. Itraconazole and luliconazole had the highest sensitivity amongst systemic and topical antifungals, respectively. It also showed that terbinafine had comparatively less sensitivity to most organisms.
Epidemiological study of burn admissions in a tertiary burn care center of Bihar, India
Indian Journal of Burns, 2019
Background: Burn injury remains one of the biggest health concerns in the developing world and is... more Background: Burn injury remains one of the biggest health concerns in the developing world and is a formidable public health issue in terms of mortality, morbidity, and permanent disability. Aims and objectives: To study the epidemiological aspects of burn admission in a tertiary care burn centre of Bihar. Materials and Methods: This study is a retrospective hospital based observational study, being conducted at Patna Medical College Hospital (PMCH), Patna from 1.1.2018 to 31.12.2018. All burn patients (n = 1431) admitted during this period were included in this study. Results: In our region, burn admissions showed 2 seasonal peaks (April, May) & (Nov, Dec). Females of age 20-39 years were most commonly affected. Accidental injuries were more common than suicidal & homicidal cases. Flame burn leaded the cause followed by electric burn. Most burn victims belonged to rural background & low socio-economic strata. Kitchen was the most common place & kerosene oil most common agent causing burn. Majority of patients presented late to our hospital i.e. after 4 hours. In our scenario, mortality of burn patients with total body surface area (TBSA) > 60% was 95%. Conclusion: Young females of rural background & low socio-economic strata are the commonest victim of burn injuries. Majority of cases are accidental thermal burn. Mortality rate is high in patients with TBSA > 60%. Appropriate preventive & therapeutic measures need to be taken in terms of social education & provision of quality healthcare to reduce the incidence & improve the survival outcome of burn patients.
International Journal of Emerging Research in Management and Technology, 2018
Aluminium Metal Matrix Composites (AMMCs) are the new class of materials substituting many indust... more Aluminium Metal Matrix Composites (AMMCs) are the new class of materials substituting many industrial materials. It is due to its superior qualities compared to conventional materials. AMMCs has found a versatile application because it has aluminium in matrix phase hence light in weight and also it can acquire different properties as per reinforcements used. Sintering is one of the prominent methods used to manufacture AMMCs. Sintering process is used in Powder Metallurgy in which small powdered particles are heated to bond together. The process enhances the strength as well as other mechanical and tribological properties. The technology enables us to shape materials difficult to machine, parts with complex geometries, materials having high melting point, parts with close dimensional tolerances, or to combine different materials which is not possible with any other process. The most important part is that the density of the product can be controlled according to the requirements an...
Atmospheric Measurement Techniques, 2018
Oxidation flow reactors (OFRs) have been developed to achieve high degrees of oxidant exposures o... more Oxidation flow reactors (OFRs) have been developed to achieve high degrees of oxidant exposures over relatively short space times (defined as the ratio of reactor volume to the volumetric flow rate). While, due to their increased use, attention has been paid to their ability to replicate realistic tropospheric reactions by modeling the chemistry inside the reactor, there is a desire to customize flow patterns. This work demonstrates the importance of decoupling tracer signal of the reactor from that of the tubing when experimentally obtaining these flow patterns. We modeled the residence time distributions (RTDs) inside the Washington University Potential Aerosol Mass (WU-PAM) reactor, an OFR, for a simple set of configurations by applying the tankin-series (TIS) model, a one-parameter model, to a deconvolution algorithm. The value of the parameter, N, is close to unity for every case except one having the highest space time. Combined, the results suggest that volumetric flow rate affects mixing patterns more than use of our internals. We selected results from the simplest case, at 78 s space time with one inlet and one outlet, absent of baffles and spargers, and compared the experimental F curve to that of a computational fluid dynamics (CFD) simulation. The F curves, which represent the cumulative time spent in the reactor by flowing material, match reasonably well. We value that the use of a small aspect ratio reactor such as the WU-PAM reduces wall interactions; however sudden apertures introduce disturbances in the flow, and suggest applying the methodology of tracer testing described in this work to investigate RTDs in OFRs to observe the effect of modified inlets, outlets and use of internals prior to application (e.g., field deployment vs. laboratory study).
Study of Agglomeration Behavior of Chemical Mechanical Polishing Slurry under Controlled Shear Environments
ECS Journal of Solid State Science and Technology, 2018
Method for Determining Stability of CMP Slurry
ECS Journal of Solid State Science and Technology, 2018
IOSR Journal of Dental and Medical Sciences, 2017
The opportunistic mycoses are those fungal infections which are found in patients whose immunolog... more The opportunistic mycoses are those fungal infections which are found in patients whose immunological defence mechanisms are weakened by cancer,AIDS, etc. In patient with AIDS, incidence of opportunistic mycoses are inversely correlated with the CD4 lymphocyte count. Our aim was to establish a correlation between fungal infections and CD4+ T cell count, evaluate prevalence of fungal infections in HIV patients , correlate fungal speciation and CD4+ T cell count .SDA, SDCA, SDCCA were used as isolation culture media. Moulds and their species were identified by colony morphology and Teasing and LCB mount findings. Candida spp. was the most common(101, 94.39%) isolated fungus followed by Aspergillus spp.(3.74%) and Rhizopus spp. (1.87%).Candida isolates were found in any ranges of CD4 cell count from 200 to less than 50, Aspergillus spp.was isolated from patients having CD4 cell count <50 and Rhizopus spp. were found in patients having CD4 cell count not more than 100. It was concluded that oral candidiasis is the commonest opportunistic fungal infections in HIV seropositive patients in this part of India. Almost all the patients having CD4 cell count less than 200.
International Journal Of Community Medicine And Public Health, 2017
Background: Maternal health reflects the overall effectiveness of the health system of any countr... more Background: Maternal health reflects the overall effectiveness of the health system of any country. One strategy for reducing maternal mortality and morbidity is ensuring that every baby is delivered in an institution. Government of India has launched various health schemes under the umbrella of National Rural Health Mission (NRHM) to promote institutional deliveries. Thus this study was conducted to study the changing trends in place of delivery in rural women in relation to NRHM.Methods: A community based cross-sectional study was conducted in the field practice area of rural health training center (RHTC), Paithan, Dist. Aurangabad during the period of 1st October 2015 to 31st March 2016. All the villages under two sub-centers of one PHC under the RHTC were selected for the study. All women above 18 years of age who delivered at least once between 1st January 2001 to 31st December 2015, were interviewed for their place of delivery.Results: Institutional deliveries increased from 4...
International Journal Of Community Medicine And Public Health, 2017
Background: Of all work settings, hospitals carry the greatest risk of verbal abuse and threats, ... more Background: Of all work settings, hospitals carry the greatest risk of verbal abuse and threats, with 73% of staff on medical premises suffering abuse. The scenario in Indian subcontinent is also not so bright. Doctors are frequently assaulted in India as well where doctors are shot, even stabbed. Thus this study was undertaken to know the exact prevalence of such incidences in Paithan taluka of Aurangabad district. Methods: A community based cross-sectional study was done in the Paithan taluka of Aurangabad district in Maharashtra from October 2015 to December 2015. All the doctors in the urban as well as rural areas of Paithan were interviewed to know their experiences about episodes of workplace violence (WPV) during last 12 months as well as their lifetime experiences. Some of the factors associated with the WPV were also asked along with the perceived reasons for such type of incidences. Results: The prevalence of workplace violence in the last 12 months was found to be 63.41%,...
International journal of surgery case reports, Jan 12, 2016
Hydatid cyst is a common health problem of world in sheep grazing area. Liver is the most commonl... more Hydatid cyst is a common health problem of world in sheep grazing area. Liver is the most commonly involved organ. Splenic hydatid cyst is uncommon and its isolated involvement is very rare. We are presenting a case of isolated hydatid cyst of spleen in a sixty one year old female patient with complaints of pain in the left hypochondrium, dyspepsia and features of gastritis for the last 1 year. The diagnosis was confirmed by Contrast enhanced CT scan (CECT). Laparoscopic splenectomy was performed. The aim of this case report is to emphasize that the most important factor in diagnosing splenic hydatid cyst is the awareness of its possibility and the intraoperative precautions which will decrease morbidity and mortality in the postoperative period.
Patterned Articles and Light Emitting Devices Therefrom
Influence of diversification of rice (Oryza sativa)–wheat (Triticum aestivum) system on productivity, energetics and profitability under on-farm conditions
Indian Journal of Agronomy, 2014
A field experiment was conducted at farmers’ fields in the district of Dehradun, Uttarakhand, dur... more A field experiment was conducted at farmers’ fields in the district of Dehradun, Uttarakhand, during 2009–10 and 2010–11, to find out the alternate efficient cropping systems for rice (Oryza sativa L.)–wheat [Triticum aestivum (L.) emend. Fiori & Paol.] in western Himalayas. Five cropping systems including the existing rice–wheat system were tested at 12 farmers’ fields as researcher designed farmer managed trials. The wheat equivalent yield under the rice–potato (Solanum tuberosum L.)–greengram [Vigna radiata (L.) Wilczek], rice–potato–vegetable cowpea [Vigna unguiculata (L.) Walp.] and rice–vegetable pea (Pisum sativum L.)–vegetable Frenchbean (Phaseolus vulgaris L.) was 135, 124 and 105% higher than the rice–wheat system. The rice–potato–greengram cropping system recorded highest net returns (1,61,928/ha), followed by rice–vegetable pea–vegetable Frenchbean (1,58,192/ha) and rice–potato–vegetable cowpea cropping systems (1,52,415/ha). The highest benefit: cost ratio (1.93) was recorded with the rice–vegetable pea–vegetable Frenchbean cropping system owing to its lower cost of cultivation and higher returns.
International Journal of Computer Theory and Engineering, 2012
The need for an efficient technique for compression of Images is ever increasing because the raw ... more The need for an efficient technique for compression of Images is ever increasing because the raw images need large amounts of disk space seems to be a big disadvantage during transmission and storage. In this paper, an efficient algorithm has been proposed for lossy image compression/decompression scheme using histogram based block optimization and arithmetic coding. Experimental result shows that the proposed algorithm gives better compression ratio as that of JPEG and some other techniques and PSNR value of decompressed image is comparable to JPEG.
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Papers by Purushottam Kumar