Dileep Singh Chauhan  Rashmi Agrawal  Priyanka Rastogi 《Numerical Heat Transfer, Part A: Applications》2013,63(2):136-157

This study considers magnetohydrodynamic flow and heat transfer outside a hollow stretching cylinder immersed in a fluid saturated porous medium of sparse distribution of particles with high permeability. Partial slip boundary conditions for the velocity and temperature fields are assumed at the stretching surface of the cylinder. Using similarity transformations, the nonlinear partial differential equations governing the flow and heat transfer are converted into nonlinear ordinary differential equations which are then solved by the homotopy analysis method. The effects of the pertinent parameters on the velocity and temperature profiles are investigated and discussed graphically.  相似文献   

    

Satish Saini 《Refocus》2004,5(3):52-54

A balance between electricity supply and demand is needed at all times to ensure a stable and reliable market. This can be done in two ways, either by Supply-side Management by adding supply when demand is high or by Demand-Side Management (DSM) by curtailing the system demand when supply availability is less. Satish Saini explores the benefits of DSM as a solution to supply shortage and alternative to new plant build.  相似文献   

    

Anil Kumar;Divya Rani;Anjali Saini;Neeraj Joshi;Ravi Kumar Varma;Mrinal Dutta;Arup Samanta; 《Solar RRL》2024,8(9):2400014

Thin silicon solar cells can be a low-cost effective photo-conversion device, if the device can efficiently absorb the solar spectrum. Herein, a new lithography-free technique is developed for the fabrication of quasiperiodic silicon inverted-pyramids arrays (SiIPAs), which show a high-light-trapping phenomenon in the ultraviolet–visible—near-infrared (300–2000 nm). Fabricated SiIPA samples show a significant reduction of reflectance (3%) in the silicon absorption band (300–1000 nm). A unique additional absorption of 33–44% compared to the planar silicon is observed in the sub-bandgap region of silicon (1100–2000 nm) for these samples. Photocurrent response measurement confirms the generation of additional electron–hole pairs in the sub-bandgap region of silicon for the SiIPA samples in comparison with planar sample. In these results, the effect of field confinement and the creation of optical resonance modes within these structures, qualitatively supported by numerical simulation, are signified. The estimated short-circuit current density using the experimental absorption spectrum of SiIPAs is 55.46 mA cm−2, which is far higher than the Lambertian limit of ≈43 mA cm−2. The theoretical efficiency of the solar cell can be achieved up to 35.22%, which surpasses the Shockley–Queisser limit of 33.7%.  相似文献   

    

Chanhyuk Choi;Junghyun Lee;Shuvaraj Ghosh;Malkeshkumar Patel;Junsik Lee;Priyanka Bhatnagar;Naveen Kumar;Chidingozi Emeka Osigwe;Joondong Kim; 《Solar RRL》2024,8(4):2300936

Is it possible to achieve efficient energy control without it being visible? If it could, it would enable human to produce energy in a transparent manner and manage energy usage intelligently by reducing consumption through building and vehicle windows, and other structures. Herein, thin films are created that are highly transparent and can filter light by selecting specific wavelengths. The films consist of multiple layers of ITO/Ag/ITO/Ag/ITO (IAIAI) that are designed to reflect light selectively using the Bragg reflection effect. These films are able to block an average of 89.6% of near-infrared light in the 800–1400 nm range, while maintaining a high optical transparency of 69.2% (±0.1%) at 550 nm with an excellent sheet resistance value of 1.06 Ω □−1. The IAIAI structure is also used as electrodes for transparent photovoltaic (TPV) devices, allowing for the collection of photogenerated carriers while ensuring overall optical transparency. ZnO/NiO-based TPV devices using IAIAI films as transparent conducting electrodes are found to have a high open-circuit voltage value of 271 mV with a short-circuit current density value of 1.55 mA cm−2. Thus, the multifunctional IAIAI films offer a range of possibilities for transparent energy devices.  相似文献   

    

Xinyi Xu  Rajan Saini  Enver Koray Akdoğan  John Stuart McCloy  Ashutosh Goel 《Journal of the American Ceramic Society》2023,106(6):3375-3395

Owing to its good chemical and thermal durabilities at high temperatures, Monofrax K-3 refractory is widely used in nuclear waste vitrification as a lining material in melting vessels. However, the corrosion of K-3 refractory during the vitrification of nuclear waste is a serious problem because it affects the melter's safety, performance, and lifetime. Therefore, in the present study, we have focused on unearthing the impact of glass network formers, such as SiO₂, B₂O₃, and Al₂O₃, in a model nuclear waste glass composition on the corrosion of Monofrax K-3 refractory. The corrosion tests have been performed per ASTM C621 at 1150°C for 5 days. The dimensional measurements on corroded K-3 refractory suggest that Al₂O₃ and SiO₂ tend to reduce the refractory corrosion (neck loss), with the effect of Al₂O₃ being significant. A corroded region on the K-3 refractory at the melt–refractory interface is observed. The corrosion occurs via a coupling of the melt infiltration induced by a capillary effect and the dissolution of Al, Mg, and Fe components from K-3 into the melt through chemical reactions. A Cr-rich layer is retained on the glass contact surface of the corroded K-3 refractory.  相似文献   

    

Priyanka Rade;Shubhangi Swami;Varsha Pawane;Ranjit Hawaldar;Vijaya Giramkar;Shany Joseph;Bharat Kale; 《Polymer Engineering and Science》2024,64(5):2202-2213

Digital light processing (DLP) based three-dimensional (3D) printing technology which uses photocurable resin has been a center of interest due to its printing accuracy and printing speed. In our research, we have synthesized and modified the bisphenol A-based epoxy acrylate resin for the DLP 3D printer having a printing accuracy of 50 μm. As the viscosity plays an important role in printing accuracy, the resin was modified with mono-functional, di-functional, tri-functional, and combination of di-tri functional acrylate diluents as well as with photoinitiator to achieve the desired level of viscosity. The process parameters like curing time and intensity were optimized using the DLP 3D printer. The uncured and UV-cured samples were characterized using FTIR-ATR, 1HNMR, UV–VISIBLE, and TGA techniques. The analysis of the uncured and UV-cured samples was carried out using viscosity, gel content, water absorption, and chemical resistance test. The mechanical properties of the UV-cured samples were determined using hardness and tensile strength test. The 3D-printed samples were observed under high-resolution microscope to confirm the printing quality and resolution. The resulting outcome confirmed that the proper selection of diluents is an important parameter for achieving the good quality and resolution of samples printed using the DLP 3D printer technology.  相似文献   

    

Priyanka Yadav;Sudhir G. Warkar;Anil Kumar; 《Polymer Engineering and Science》2024,64(10):4816-4833

The present study describes the facile synthesis of graphene oxide (GO) and GO/carboxymethyl tamarind kernel gum (CMTKG)-based hydrogel composite. The synthesized GO/CMTKG/PAM hydrogel composite was applied as an adsorbent for the selective sequestration of toxic crystal violet (CV) and methylene blue (MB) from an aqueous medium. The impact of various controlling parameters such as contact time, pH, concentration, adsorbent dosage, and temperature was studied. The experimental data obtained from the isotherm and kinetics modeling showed a good correlation with the Langmuir isotherm and pseudo-second-order kinetics model, respectively. The optimized concentration of dye was 40 mg L−1 for CV and 20 mg L−1 for MB, and the adsorption capacity (qmax) was calculated to be 111 mg g−1 for CV dye and 25 mg g−1 for MB dye. The synthesized adsorbent exhibits excellent recyclability for dye uptake after six consecutive cycles. Furthermore, the simultaneous adsorption of CV and MB from the binary system was carried out to ascertain the utility of the adsorbent in a wide range of adsorption systems. The adsorbent was also found to act as a proficient adsorbent in various water samples. These results demonstrated that synthesized hydrogel can be successfully applied as an adsorbent for the sequestration of dye effluents in real-time applications.  相似文献   

    

Priyanka Sharan  Abdallah Daddi-Moussa-Ider  Jaime Agudo-Canalejo  Ramin Golestanian  Juliane Simmchen 《Small (Weinheim an der Bergstrasse, Germany)》2023,19(36):2300817

Due to the intrinsically complex non-equilibrium behavior of the constituents of active matter systems, a comprehensive understanding of their collective properties is a challenge that requires systematic bottom–up characterization of the individual components and their interactions. For self-propelled particles, intrinsic complexity stems from the fact that the polar nature of the colloids necessitates that the interactions depend on positions and orientations of the particles, leading to a 2d − 1 dimensional configuration space for each particle, in d dimensions. Moreover, the interactions between such non-equilibrium colloids are generically non-reciprocal, which makes the characterization even more complex. Therefore, derivation of generic rules that enable us to predict the outcomes of individual encounters as well as the ensuing collective behavior will be an important step forward. While significant advances have been made on the theoretical front, such systematic experimental characterizations using simple artificial systems with measurable parameters are scarce. Here, two different contrasting types of colloidal microswimmers are studied, which move in opposite directions and show distinctly different interactions. To facilitate the extraction of parameters, an experimental platform is introduced in which these parameters are confined on a 1D track. Furthermore, a theoretical model for interparticle interactions near a substrate is developed, including both phoretic and hydrodynamic effects, which reproduces their behavior. For subsequent validation, the degrees of freedom are increased to 2D motion and resulting trajectories are predicted, finding remarkable agreement. These results may prove useful in characterizing the overall alignment behavior of interacting self-propelling active swimmer and may find direct applications in guiding the design of active-matter systems involving phoretic and hydrodynamic interactions.  相似文献   

    

Srishti Vashisht  Naresh Singh  Akansha Sharma  Neeru Saini  Shailendra Nath Gaur  Naveen Arora 《Journal of the science of food and agriculture》2023,103(2):877-890

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Priyanka B.N.  Jayaparvathy R 《International Journal of Communication Systems》2023,36(15):e5561

A wireless body area network (WBAN) enables the continuous monitoring of health conditions including heart rate, temperature, and glucose levels. It is composed of several sensors that are placed on the body. The network's performance is significantly affected by the unpredictable movements of the human body. Due to the varying proximities between them, the existence of several WBANs creates a challenge when mobility is involved. In this fictitious scenario, we consider a park area with both mobile and static WBANs or WBAN-equipped individuals passing through the park who have varying degrees of mobility. When a mobile WBAN passes a static WBAN and is within a minimum distance of the static WBAN, they pair up and immediately interfere. Inter-interference caused by WBANs operating in a limited area causes packet loss and performance deterioration. In this work, static WBAN locations are optimised to minimise interference and system inter-interference problems are addressed by a game theoretic method. This paper formulates a flexible game theoretic framework to study WBAN coexistence using the expected pay-off function considering a two-player game. It is observed from the results obtained that the probability of interference caused by fast mobile WBANs is reduced to a maximum of 50% compared with that caused by slow mobile WBANs thereby reducing the need for relocation of static WBANs.  相似文献