Spin-orbit-coupling induced lateral spin transport from first principles

Everything digital is currently stored in data centres on magnetic hard disk drives which are accessed at will using a magnetic read head. The spinning disks and moving read heads in the hard disks imply slow access time and high-power consumption making data centres giant sponges for electricity. At the same time, semiconductor based storage suffers from thermal dissipation with miniaturization on top of data leakage and high cost. The ideal memory for data storage would be cost-effective, non-volatile, fast and consume less power, combining desirable features of both magnetic and semiconductor storage technology. To this end, the field of “spintronics" promises a new direction towards efficient data storage using magnetic memories. The impetus for the research that has gone into realizing this thesis was fuelled by uncertainties in the reported spin transport parameters and the gap between phenomenological models and experiments in (spin)transport phenomena. The aim of the thesis is to resolve some of the uncertainties by pushing our computational capabilities in investigating microscopic details of transport. Furthermore, I attempt to improve upon existing models of interpretation or prediction used in experiments and application. I studied a number of topics in the field of electronic spin transport in transition metals. Because of their partially filled d-bands and complex Fermi surfaces with spin-orbit coupling, transition metals are rich in spin phenomena that have potential for spintronics applications. Using a density functional theory-based scattering approach, I studied the generation and diffusion of spin currents in non-magnetic 5d and ferromagnetic 3d transition metals. By including thermal disorder, I presented realistic calculations for these metals. I next studied lateral transport in finite size geometries that are encountered in spintronics experiments. This form the last three chapters of the thesis. The main focus of the thesis has been on the determination of the two most important spin-orbit coupling related spin transport properties, the spin flip diffusion length and the spin Hall angle

Proposed System for a Smart Grid Implementation at Oklahoma State University

The concept of a Smart Grid has so far been the biggest technological boom for the mature energy and power industry. With billions of dollars in smart grid investments, it has been the talk of the town in an era of climate change and globalization. The effective utilization of smart grid technologies for bi-directional power flow, integration of renewable energy generation technologies, internet and high-speed two-way communications are vital. Further, intelligent sensing and switching technologies with higher redundancy in the power delivery sector are needed to provide effective system restoration, increasing power quality and overall system reliability. This study provides a brief overview of the current distribution system at the Stillwater campus of Oklahoma State University and the challenges it faces. It further presents how the campus may adapt different strategies involving distribution automation and smart grid concepts in terms of voltage sensors and current sensors to transform the current grid into a Smart Grid, thus reducing power outages and improving voltage profiles at critical buses. Different scenarios are proposed with corresponding simulation results and operational logic diagrams illustrating the implementation of the proposed system at the Stillwater campus of Oklahoma State University.School of Electrical & Computer Engineerin

Genetic dissection of itpr gene function reveals a vital requirement in aminergic cells of Drosophila larvae

Signaling by the second messenger inositol 1,4,5-trisphosphate is thought to affect several developmental and physiological processes. Mutants in the inositol 1,4,5-trisphosphate receptor (itpr) gene of Drosophila exhibit delays in molting while stronger alleles are also larval lethal. In a freshly generated set of EMS alleles for the itpr locus we have sequenced and identified single point mutations in seven mutant chromosomes. The predicted allelic strength of these mutants matches the observed levels of lethality. They range from weak hypomorphs to complete nulls. Interestingly, lethality in three heteroallelic combinations has a component of cold sensitivity. The temporal focus of cold sensitivity lies in the larval stages, predominantly at second instar. Coupled with our earlier observation that an itpr homozygous null allele dies at the second instar stage, it appears that there is a critical period for itpr gene function in second instar larvae. Here we show that the focus of this critical function lies in aminergic cells by rescue with UAS-itpr and DdCGAL4. However, this function does not require synaptic activity, suggesting that InsP3-mediated Ca2+ release regulates the neurohormonal action of serotonin

Advancing Treatment Frontiers: Radiofrequency Ablation for Small Renal Mass—Intermediate-Term Results

Our study aims to discern the immediate and intermediate-term oncological outcomes of the patients with small renal mass and who were surgically unfit or were having a bilateral tumor and underwent radiofrequency ablation (RFA) of the mass. We retrospectively and prospectively analyzed the status of the patients who were diagnosed to have small renal masses and were biopsy-proven renal cell carcinoma (RCC) cases, who underwent RFA at our institute from the year 2013 to 2022. Patients were followed-up for 3 years. Data regarding complications were analyzed for all patients who underwent renal RFA along with the 3-year recurrence-free survival (RFS) rate. A total of 28 patients were eligible for the study based on our inclusion and exclusion criteria. Their renal function was recorded. They underwent RFA and were followed-up for a period of 3 years for RFS. Four patients out of the total had immediate complications, out of which two developed a hematoma. Three-year-follow-ups showed six recurrences, overall having 78.6% RFS. Post-procedural renal function was stable as documented by estimated glomerular filtration rate. Oncological results of RFA in patients with small renal masses who are surgically unfit are associated with a low risk of immediate and intermediate-term deterioration of renal function

Arachnoid web: a mystery unravelled

A 47-year-old lady came with complaints of dull aching low backache and numbness over both the lower limbs since six months, aggravated since one week. She had tenderness over dorsal (D8-D10) and lumbar (L4-L5) spinal and paraspinal regions. Radiographs were inconclusive. Plain and contrast Magnetic resonance imaging (MRI) of the dorso-lumbar (D-L) spine with whole spine screening were also inconclusive initially. But close observation and serial viewing of all the sections revealed features of an arachnoid web at D7-D8 vertebral level. Patient underwent D7, D8 laminectomy with durotomy and arachnoid web excision. She had considerable improvement in her symptoms after the surgery. Hence, prompt recognition and early surgery ensure good outcomes in this uncommon yet relevant clinical entity

Exploring the Potential of Microgrids in the Effective Utilisation of Renewable Energy : A Comprehensive Analysis of Evolving Themes and Future Priorities Using Main Path Analysis

Microgrids are energy systems that can operate independently or in conjunction with the main electricity grid. Their purpose is to link different energy sources, enhance customer participation in energy markets, and improve energy system efficiency and flexibility. However, regulatory, technical, and financial obstacles hinder their deployment. To comprehend the current state of the field, this study utilized citation network analysis (CNA) methodology to examine over 1500 scholarly publications on microgrid research and development (R&D). The study employed modularity-based clustering analysis, which identified seven distinct research clusters, each related to a specific area of study. Cluster 1, focused on control strategies for microgrids, had the highest proportion of publications (23%) and the maximum citation link count (151), while Cluster 4, which examined microgrid stability, had the lowest proportion of papers (10%). On average, each publication within each cluster had four citation links. The citation network of microgrid research was partitioned using cluster analysis, which aided in identifying the main evolutionary paths of each subfield. This allowed for the precise tracing of their evolution, ultimately pinpointing emerging fronts and challenges. The identification of key pathways led to the discovery of significant studies and emerging patterns, highlighting research priorities in the field of microgrids. The study also revealed several research gaps and concerns, such as the need for further investigation into technical and economic feasibility, legislation, and standardization of microgrid technology. Overall, this study provides a comprehensive understanding of the evolution of microgrid research and identifies potential directions for future research.publishedVersio

Occurrence of ribbonfish in the Indian EEZ

The survey conducted by FORV Sagar Sampada during 1985-91 (90 cruises) revealed the occurrence of ribbonfish in 56 stations out of 904 stations where fishing was conducted. It was reported from 41 stations along the west coast and 14 stations along the east coast. About 14 tonne of ribbonfish was caught in these operations which formed 4.8% of the total fish catch. West coast was more productive and contributed 93.6% of the catch, while the east coast only 6.4%. It abundantly occurred in the southwest, centralwest, northwest and northeast coasts. Depth-wise study revealed that major portion of the catch was obtained from within the 100 m depth zone. The dominant species reported was Trichiurus leptur