Low Field Magneto-transport and Thermal Studies on (1-x) Pr<SUB>2/3</SUB>Ba<SUB>1/3</SUB>MnO₃+x PdO Composite Manganites

Neeraj Panwar,Neeraj Kumar,Vikram Sen,D. K. Pandya,S. K. Agarwal 한국자기학회 2008 한국자기학회 학술연구발표회 논문개요집 Vol.- No.-

Thin and Broadband Two‑Layer Microwave Absorber in 4–12 GHz with Developed Flaky Cobalt Material

Neeraj Gill,Jaydeep Singh,Smitha Puthucheri,Dharmendra Singh 대한금속·재료학회 2018 ELECTRONIC MATERIALS LETTERS Vol.14 No.3

Microwave absorbing materials (MAMs) in the frequency range of 2.0–18.0 GHz are essential for the stealth and communicationapplications. Researchers came up with effective MAMs for the higher frequency regions, i.e., 8.0–18.0 GHz,while absorbers with comparable properties in the lower frequency band are still not in the limelight. Designing a MAMfor the lower frequency range is a critical task. It is known that the factors governing the absorption in this frequency predominantlydepend on the permeability and conductivity of the material, whereas the shape anisotropy of the particles caninitiate different absorption mechanisms like multiple internal reflections, phase cancellations, surface charge polarizationand enhanced conductivity that can promote the microwave absorption towards lower frequencies. But the material alone maynot serve the purpose of getting broad absorption bandwidth. With the effective use of advanced electromagnetic techniquelike multi-layering this problem may be solved. Therefore, in this paper, a material with shape anisotropy (cobalt flakes withhigh shape anisotropy) has been prepared and a two-layer structure is developed which gives the absorption bandwidth in4.17–12.05 GHz at a coating thickness of 2.66 mm.

Investigations of Ferroelectric Polarization Switching in Potassium Nitrate Composite Films

Neeraj Kumar,Rabinder Nath 한국전기전자재료학회 2014 Transactions on Electrical and Electronic Material Vol.15 No.2

This article explains the experimental results of ferroelectric polarization switching (FPS) of potassium nitrate (KNO3)with different polymers such as polyvinylidene fluoride (PVDF) and polyvinyl fluoride (PVF) using simple melt-presstechniques. To analyze the ferroelectric polarization switching in potassium nitrate (KNO3) composite films at roomtemperature, we applied the Ishibashi and Takagi theory (based on Avrami model) to the switching current transient. To investigate the dimensionality of domain growth, the ferroelectric polarization switching current (FPS current)was observed from the square - wave bipolar signals across a resistance of 0.1 kΩ in series with the composite films. The existence of a switching current transient pulse confirmed the ferroelectricity and indicated the stability of theferroelectric phase (phase III) of KNO3 at room temperature. Polarization hysteresis (P-E) characteristics supportedthe prominent features of ferroelectric polarization switching in the composite films at room temperature.

Doctor Consultation through Mobile Applications in India: An Overview, Challenges and the Way Forward

Neeraj Agarwal,Bijit Biswas 대한의료정보학회 2020 Healthcare Informatics Research Vol.26 No.2

Objectives: To layout mHealth (mobile health) applications operating in India with the facility of either online doctor consultation or offline doctor appointment booking. Methods: A cross-sectional, observational and web-based study was conducted. We searched the Google Play Store with the search strategy “health apps in India”. In the results, 250 applications (apps) appeared. Out of 250 apps, finally, 22 apps were found to be providing online doctor consultation and/or doctor appointment booking-related services. Results: Among the selected mHealth apps operating in India and providing doctor consultationrelated services online/offline, Practo, mfine, DocsApp, 1mg, Netmeds, Lybrate, MediBuddy, and Medlife were found to be the eight most popular ones with over a million downloads and on average four-plus user rating out of five. Practo, mfine, and Lybrate offer doctor consultation through chat, audio, and video calling. Netmeds and DocsApp offer doctor consultation through both chat and audio call. 1mg offers free chat consultation, while MediBuddy and Medlife offer audio call consultation only. Considering booking doctor appointments for offline consultation, Practo, mfine, 1mg, and Lybrate only offer this facility among the eight most popular selected mHealth apps. Conclusions: mHealth apps providing doctor consultation are gaining popularity in India, and they have enormous potential in the country. The government should make enabling policies to facilitate and popularise mHealth apps.

Effect of Metallic Interfacial Layers on the Properties of Diamond-Like Carbon Thin Films

Neeraj Dwivedi,Sushil Kumar,Sreekumar C,Saurabh Dayal,C. M. S. Rauthan,O.S. Panwar 대한금속·재료학회 2012 METALS AND MATERIALS International Vol.18 No.2

Diamond like carbon (DLC) thin films with metallic interfacial layers of aluminum and nickel-chromium (Al and Ni-Cr) were grown using a low cost hybrid technique involving a resistive heating thermal evapo-rator and radio frequency plasma enhanced chemical vapor deposition techniques. Stress, hardness, elastic modulus, bonding, phase, and electrical conductivity of these films were investigated. Introduction of interfacial Al and Ni-Cr layers in DLC led to drastic improvement of its conductivity along with a signifi-cant reduction in residual stress but with some reduction of hardness and the elastic modulus. The struc-tural and surface properties of thin films were studied using X-ray diffraction, X-ray photoelectron spectroscopy, and scanning electron microscopy techniques.

Multi-stage System for Preprocessing Mammograms

Neeraj Shrivastava,Jyoti Bharti 대한전자공학회 2020 IEIE Transactions on Smart Processing & Computing Vol.9 No.2

Breast image analysis is important for the detection and diagnosis of various diseases, but more specifically, breast cancer. The most popular and widely used screening tool is mammography. It gives a better result than other screening tools for breast image analysis. Mammograms are difficult to analyze because of noise, poor quality, artifacts, and the inclusion of pectoral muscle. The technique proposed in this paper has several stages for preprocessing mammograms. First, artifacts and the background are removed by changing the original image into a binary image using Otsu’s thresholding. The medio-lateral view of mammography images has two orientations: left or right. Orientation detection in the next step is important for pectoral muscle removal, which is done using the line segment method. Contrast is enhanced using contrast limited adaptive histogram equalization, and noise is reduced using a median filter. The proposed technique was applied to a publicly available dataset from the Mammographic Image Analysis Society, from which 322 images were analyzed, and performance parameters calculated. After calculations for accuracy, sensitivity, and specificity, the accuracy achieved was 94.62%, sensitivity achieved was 90.21%, and specificity was 97.20%.

Optimized biodiesel yield in a hydrodynamic cavitation reactor using response surface methodology

Neeraj Budhraja,R.S. Mishra Techno-Press 2022 Advances in energy research Vol.8 No.4

Biodiesel is a non-polluting and non-toxic energy source that can replace conventional diesel. However, the higher production cost and raw material scarcity became challenges that obstruct the commercialization of biodiesel production. In the current investigation, fried cooking oil is used for biodiesel production in a hydrodynamic cavitation reactor, thus enhancing raw material availability and helping better waste oil disposal. However, due to the cavitation effect inside the reactor, the hydrodynamic cavitation reactor can give biodiesel yield above 98%. Thus, the use of orifice plates (having a different number of holes for cavitation) in the reactor shows more than 90% biodiesel yield within 10 mins of a time interval. The effects of rising temperature at different molar ratios are also investigated. The five-hole plate achieves the highest yield for a 4.5:1 molar ratio at 65℃. And the similar result is predicted by the response surface methodology model; however, the optimized yield is obtained at 60℃. The investigation will help understand the effect of hydrodynamic cavitation on biodiesel yield at different molar ratios and elevated temperatures.

Influence of B4C on Dry Sliding Wear Behavior of B4C/Al–Mg–Si Composites Synthesized via Powder Metallurgy Route

Neeraj Kumar,M. K. Manoj 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.10

The aim of this work is to fabricate aluminum, boron carbide (B4C) based aluminum matrix composites (AMCs) using easyand cost effective powder metallurgy (P/M) route. Here, Al–Mg–Si composites having different weight fractions of B4C(3.5,7.0,10.5,14.0 and 17.5 wt%) were synthesized to study the dry sliding wear behavior with respect to automobile brakepad material. The surface morphology and elemental composition of fabricated composite material were characterized byScanning Electron Microscope (SEM) and energy dispersive x-ray spectroscopy (EDS) respectively. Further, dry sliding weartests were conducted with respect to i.e. applied loads, sliding distances and reinforcements for the performance analysis ofsynthesized AMCs. A linear regression model was used to optimize the control factors. Furthermore, explore the effects ofreinforcements on density, Vickers hardness, wear rate and worn out surface morphology. Further, the analysis also revealedthe critical wear mechanisms with their wear debris for improvement in the AMCs. The hardness of aluminum composite(17.5% B4C/Al–Mg–Si) showed 54.15% higher value than matrix alloy. Furthermore, it was observed that AMCs showedsignificant improvement on the various factors e.g., applied load (L), sliding distances (SD) and reinforcements (R) thanthat of aluminium matrix alloy.

Operator Revenue Maximizing Heuristics with QoS Guarenetees for Real Time Traffic in 4G Networks

( Neeraj Poudyal ),( Ha Cheol Lee ),( Byung Seub Lee ) 한국인터넷정보학회 2011 KSII Transactions on Internet and Information Syst Vol.5 No.5

This paper attempts to maximize the operator`s revenue while simultaneously providing a multi-constraint, multi-hop and deterministic QoS provisioning for real time traffic in IEEE 802.16m based 4G networks. The optimal solution to such a problem is NP-complete and therefore not feasible to be solved in a tolerable polynomial time. For this reason, we also provide a simple price based greedy heuristic to be used along with the admission control. Simulation results for different QoS schemes show that the heuristic produces a revenue that is very close to the optimal revenue, and is far more aggressive than the size based and other common algorithms that are computationally feasible to be implemented in IEEE 802.16m.

Influence of Inhibitors on the Corrosion of Al and Al-composites in Chloride-containing Solutions - A Review

Neeraj Kumar,Ashok K. Srivastava,Prabhat Gautam,M. K. Manoj 한국재료학회 2022 한국재료학회지 Vol.32 No.5

Corrosion is a natural, inevitable process, and is one of the world's most serious problems. Losses incurred due to corrosion are extremely expensive for society. Several technological strategies have been explored and implemented to address these losses. The use of inhibitors to prevent corrosion is a common and efficient method to reduce corrosion losses. This review covers Al and Al-composite corrosion inhibitors in chloride-containing solutions, because of their popularity in a broad array of industrial applications. A vast number of studies in the literature detail the common tendency of Al and Al-composites with reinforcements to deteriorate. Accordingly, it is worthwhile to employ inhibitors to protect them, as discussed in the present work. The emphasis is on selecting the smartest corrosion inhibitor and evaluating its performance. According to the study, the most commonly used corrosion inhibitors are 1,4-naphthoquinone (NQ), 1,5-naphthalene diol, 3-amino-1,2,4-triazole-5-thiol (ATAT), ammonium tetrathiotungstate, clotrimazole, amoxicillin, antimicrobial and antifungal drugs. Electrochemical impedance spectroscopy (EIS), potentiodynamic (PDP), and weight loss were among the most commonly used modern electrochemical technologies to test inhibitors’ efficacy under environmental conditions.