Thermal issues at the SSC

A variety of heat transfer problems arise in the design of the Superconducting Super Collider (SSC). One class of problems is to minimize heat leak from the ambient to the SSC rings, since the rings contain superconducting magnets maintained at a temperature of 4 K. Another arises from the need to dump the beam of protrons (traveling around the SSC rings) on to absorbers during an abort of the collider. Yet another category of problems is the cooling of equipment to dissipate the heat generated during operation. An overview of these problems and sample heat transfer results are given in this paper

Spin dynamics and frequency dependence of magnetic damping study in soft ferromagnetic FeTaC film with a stripe domain structure

Perpendicular magnetic anisotropy (PMA) and low magnetic damping are the key factors for the free layer magnetization switching by spin transfer torque technique in magnetic tunnel junction devices. The magnetization precessional dynamics in soft ferromagnetic FeTaC thin film with a stripe domain structure was explored in broad band frequency range by employing micro-strip ferromagnetic resonance technique. The polar angular variation of resonance field and linewidth at different frequencies have been analyzed numerically using Landau-Lifshitz-Gilbert equation by taking into account the total free energy density of the film. The numerically estimated parameters Land\'{e} $g$-factor, PMA constant, and effective magnetization are found to be 2.1, 2$\times10^{5}$ erg/cm$^{3}$ and 7145 Oe, respectively. The frequency dependence of Gilbert damping parameter ($\alpha$) is evaluated by considering both intrinsic and extrinsic effects into the total linewidth analysis. The value of $\alpha$ is found to be 0.006 at 10 GHz and it increases with decreasing precessional frequency.Comment: 5 Pages, 6 Figures, Regular Submissio

The regulatory mechanism of the male accessory reproductive gland (ARG) of Serinetha augur (Fabr) (Heteroptera: Coreidae)—A cotton pest

The present study deals with the interrelationship of the neuroendocrine complex (NEC) and male accessory reproductive gland (ARG) of a cotton bug, Serinetha augur. The NEC consists of brain (cerebral ganglia), corpus cardiacam (CC) and corpus allatum (CA). Based on the staining reaction of aldehyde fuchsin (AF) and chrom alum haematoxylin-phloxin (CAHP), four types of neurosecretory cells have been identified in the brain. The neuroendocrine control over the ARG in S. augury was investigated through ARG extirpation (andgonadectomy)-induced hypertrophy of CA. The changing pattern of proteins in the brain during the pre- and post-mating periods (as judged by electrophoretic investigations) further supports the interrelationship of the NEC and ARG

Ferromagnetically correlated clusters in semi-metallic Ru2NbAl Heusler alloy

In this work, we report the structural, magnetic and electrical and thermal transport properties of the Heusler-type alloy Ru2NbAl. From the detailed analysis of magnetization data, we infer the presence of superparamagnetically interacting clusters with a Pauli paramagnetic background, while short-range ferromagnetic interaction is developed among the clusters below 5 K. The presence of this ferromagnetic interaction is confirmed through heat capacity measurements. The relatively small value of electronic contribution to specific heat, gamma (~2.7 mJ/mol-K2), as well as the linear nature of temperature dependence of Seebeck coefficient indicate a semi-metallic ground state with a pseudo-gap that is also supported by our electronic structure calculations. The activated nature of resistivity is reflected in the observed negative temperature coefficient and has its origin in the charge carrier localization due to antisite defects, inferred from magnetic measurements as well as structural analysis. Although the absolute value of thermoelectric figure of merit is rather low (ZT = 5.2*10-3) in Ru2NbAl, it is the largest among all the reported non-doped full Heusler alloys.Comment: 25 pages, 14 figure

ACQUIRING APPLICATION-SPECIFIC KNOWLEDGE DURING DESIGN TO SUPPORT SYSTEMS MAINTENANCE

Most large systems development efforts proceed in a top-down fashion where initial specifications and requirements are incorporated into a high-level design, followed by programs based on this design. However, a major part of the software life-cycle effort is devoted to maintenance. While several existing methodologies aid in the initial phases of requirements and specification, they have proven to be of little value for maintenance. Changes in user requirements are often translated directly to the level of code, divorcing it from the high level design it was based on. After a few such changes, the programs may not correspond to any formal high-level design, making subsequent maintenance difficult. We argue that maintenance must be based on the knowledge used in synthesizing the high-level design. This requires a development environment where the knowledge about high-level designs is formally represented, and raises the question about how this knowledge will be acquired by the support environment in the first place. In this paper, we present a model that enables the support environment to acquire design knowledge through "learning by observation" of a designer engaged in specifying a high-level design. The knowledge that the learning system begins with is a generic object for expressing design decisions. Based on the input provided by the designer, and a limited interactive querying process, it constructs and continuously refines a taxonomic classification of application-specific knowledge and rules at an appropriate level of generality that capture the rationale of the design. This knowledge can be used subsequently for maintaining system designs and recognizing design situations similar to the ones it has knowledge about.Information Systems Working Papers Serie

Congestion-aware wireless network-on-chip for high-speed communication

The design of system-on-chip (SoC) requires the complex integration between a multi-number of cores on a single chip. To establish the effective communication between multiple cores there aremore challenging issues on designing the network-on-chip (NoC) architectures. The proposed system deals with the utilization of on-chip antennas for the wireless communication between the long distance cores to minimize the latency and power. In this proposed work, we have designed high-speed wireless NoC (WiNoC) for on-chip communication. This high-speed WiNoC has been achieved by designing a congestion measure unit, which monitors and measures the congestion in the input data and establishes the effective wireless communication between the output channels and routers. The designed architecture is synthesized and implemented by using Altera Quartus II, where the SoC is designed using Qsys builder. The proposed WiNoC shows better performance parameters like throughput, latency and power than the conventional NoC

Dynamic modelling of microalgae cultivation process in high rate algal wastewater pond

In this work, a comprehensive dynamic mathematical modelling to simulate the production of microalgae in a high rate algal pond (HRAP) is attempted. A synergetic algal–bacterial system comprising various interrelated biological and chemical system processes is presented. The dynamic behaviour of HRAP system is studied by solving mass balance equations of different components which account light intensity and gas–liquid mass transfer. The model predictions are compared with the previously reported studies in the literature. The influence of kinetic and operating parameters, including the supply of CO2, the maximum growth rate, pond depth and dilution rates, on the pond performance are evaluated. The sensitivity analysis of important process parameters is also discussed in this study. The developed model, as a tool, can be used to assess the factors that affect the pond performance criteria, including algal productivity and the dynamics of nutrient requirements

Life cycle optimization for sustainable algal biofuel production using integrated nutrient recycling technology

In this study, a multi-objective optimization of sustainable integration of algal biofuel production using nutrient recycling technology, such as anaerobic digestion and hydrothermal liquefaction, is considered. Gross annual profitability and global warming potential (GWP) are the criteria chosen for the design of the algal biofuel production system. Three scenarios, such as full-scale (baseline), pilot-scale (conservative), and lab-scale (nominal), are chosen based on the expected maturity levels and nutrient demand. The results of the optimization produce Pareto sets of optimal solutions for acknowledging the trade-off between the economic and the environmental criteria of the integrated system. It is found that the anaerobic digestion (AD) technology shows better performance in terms of an environmental perspective, displacing the excessive fertilizer requirements due to its maturity in comparison with the hydrothermal liquefaction (HTL) process. However, HTL is a new, evolving, promising nutrient recycling technology which demonstrates economic preferences compared to the AD process due to its low cost of production