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1,205 results on '"Singh, Sukhwinder"'

6. Integrative Modeling and Engineering of ZnO Grain Boundaries: A Pathway to Enhanced Thermoelectric Performance

Author

Yusuf, Gbadebo Taofeek, Singh, Sukhwinder, Askounis, Alexandros, Stoeva, Zlatka, and Tchuenbou-Magaia, Fideline

Subjects
Condensed Matter - Materials Science
Abstract

Achieving higher performance in zinc oxide (ZnO) at room and mid-temperatures is crucial for applications requiring high energy conversion efficiency. This study focuses on grain boundary engineering techniques and an innovative modeling approach to optimize the thermoelectric properties of ZnO materials. An analysis was conducted to investigate the influence of grain boundaries on ZnO and evaluate its performance at mid-temperatures using the quality factor B as a descriptor.The findings indicate that the thermoelectric performance of ZnO could be significantly enhanced at low and mid-range temperatures if polycrystalline samples with engineered grain boundaries achieve low lattice thermal conductivity. An integrative model was developed to analytically examine the impact of barrier height , mean free path of carriers, and effective mass of carriers on charge mobility. Simulation results show that reducing from 0.5 eV to 0.1 eV resulted in a 45% increase in electron mobility, facilitating the overcoming of energy barriers that impede charge transport. Increasing the mean free path from 5 nm to 25 nm significantly increased charge carrier mobility, indicating fewer scattering events and higher velocities over longer distances.The study also shows that as the effective mass increases from 0.8 to 1.0, electron mobility peaks at 1.0 , suggesting an optimal balance where electron mobility is maximized. This implies an intricate interplay between carrier mass and lattice interaction forces within the material. Drawing on these insights, strategies aimed at improving the figure of merit were proposed, including microstructural engineering, advanced doping techniques, and passivation of grain boundaries. These findings provide a systematic approach to grain boundary engineering, potentially transforming ZnO into efficient materials for thermoelectric applications.

Published
2024

27. Infection and inflammation stimulate expansion of a CD74+ Paneth cell subset to regulate disease progression.

Author

Balasubramanian, Iyshwarya, Bandyopadhyay, Sheila, Flores, Juan, Bianchi-Smak, Jared, Lin, Xiang, Liu, Haoran, Sun, Shengxiang, Golovchenko, Natasha, Liu, Yue, Wang, Dahui, Patel, Radha, Joseph, Ivor, Suntornsaratoon, Panan, Vargas, Justin, Green, Peter, Bhagat, Govind, Lagana, Stephen, Ying, Wang, Zhang, Yi, Wang, Zhihan, Singh, Sukhwinder, Zhou, Zhongren, Kollias, George, Farr, Laura, Moonah, Shannon, Yu, Shiyan, Wei, Zhi, Bonder, Edward, Zhang, Lanjing, Kiela, Pawel, Edelblum, Karen, Ferraris, Ronaldo, Liu, Ta-Chiang, Gao, Nan, and Li, Wei Vivian

Subjects
CD74, Lyz1, Paneth cell, heterogeneity, lysozyme, Humans, Animals, Mice, Paneth Cells, Intestine, Small, Inflammation, Microbiota, Cytokines
Abstract

Paneth cells (PCs), a specialized secretory cell type in the small intestine, are increasingly recognized as having an essential role in host responses to microbiome and environmental stresses. Whether and how commensal and pathogenic microbes modify PC composition to modulate inflammation remain unclear. Using newly developed PC-reporter mice under conventional and gnotobiotic conditions, we determined PC transcriptomic heterogeneity in response to commensal and invasive microbes at single cell level. Infection expands the pool of CD74+ PCs, whose number correlates with auto or allogeneic inflammatory disease progressions in mice. Similar correlation was found in human inflammatory disease tissues. Infection-stimulated cytokines increase production of reactive oxygen species (ROS) and expression of a PC-specific mucosal pentraxin (Mptx2) in activated PCs. A PC-specific ablation of MyD88 reduced CD74+ PC population, thus ameliorating pathogen-induced systemic disease. A similar phenotype was also observed in mice lacking Mptx2. Thus, infection stimulates expansion of a PC subset that influences disease progression.

Published
2023

40. Synthesis and thermoelectric properties of Fe-Ti-Al based alloys

Author

Singh, Sukhwinder

Abstract

Thermoelectric materials usually refer to the materials that can use temperature difference to generate electricity, which has potential to contribute to clean energy and environment. The drawback associated with the current thermoelectric materials is that these materials usually contain highly toxic, expensive and less earth-abundant elements, which limit their economic viability of large-scale applications. This study explores the possibility of developing economically viable thermoelectric materials based on Fe-Ti-Al alloys, which are low-cost, abundant, and less-toxic. The first stage of this research focused on establishing suitable preparation conditions (such as ball milling period, cold pressing pressure, and annealing temperature) that enables fabrication of Fe11Ti3Al6 alloys with satisfactory thermoelectric properties and offers a convenient route for substitution experiments. The samples prepared after 5 hours of ball milling, followed by cold pressing under 2200 MPa and annealing at 700 0C exhibit a power factor of 12x10-5 W/mk2 with a Seebeck coefficient of 32.3µV/K and electrical resistivity of 8.6µΩm. The second stage of the research investigates the possibility of further improving thermoelectric properties of Fe11Ti3Al6 alloy through elemental substitution. A systematic investigation was carried out by substituting Fe using an element from Group V-VII (V, Mn, Cr, W, Mo) or Group IX-X (Co and Ni). It is found that the substitution using Group V-VII element resulted in an increase in the Seebeck coefficient by 6 - 32% while the substitution using Group IX-X element led to a transition from p-type to n-type - a phenomenon normally associated with semiconductors only. The final stage of the research focused on preparation and characterisation of Fe10Cr1Ti3Al6 alloy (identified in the second stage of the research) using Spark Plasma Sintering (SPS), which facilitates preparation of high-density materials. The samples prepared using the SPS technique exhibit a significantly improved power factor of 64x10-5 W/mK2 , which is approximately 5 times higher than that prepared by cold pressing and annealing. The thermoelectric properties as a function temperature were also characterised. The results show that the peak ZT of 0.02 was achieved at 98 0C.

Published
2022

49. Fuzzy informer homed routing protocol for wireless sensor network

Author

Kakamanshadi, Gholamreza, Gupta, Savita, and Singh, Sukhwinder

Subjects
Computer Science - Networking and Internet Architecture
Abstract

A wireless sensor network consists of several sensor nodes. Sensor nodes collaborate to collect meaningful environmental information and send them to the base station. During these processes, nodes are prone to failure, due to the energy depletion, hardware or software failure, etc. Therefore, fault tolerance and energy efficiency are two important objectives for reliable packet delivery. To address these objectives a novel method called fuzzy informer homed routing protocol is introduced. The proposed method tries to distribute the workload between every sensor node. A fuzzy logic approach is used to handle uncertainties in cluster head communication range estimation. The simulation results show that the proposed method can significantly reduce energy consumption as compared with IHR and DHR protocols. Furthermore, results revealed that it performs better than IHR and DHR protocols in terms of first node dead and half of the nodes alive, throughput and total remaining energy. It is concluded that the proposed protocol is a stable and energy efficient fault tolerance algorithm for wireless sensor networks., Comment: 18 pages,13 Figures, 7 Tables

Published
2019

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