Review and analysis of dense linear system solver package for distributed memory machines

A dense linear system solver package recently developed at the University of Texas at Austin for distributed memory machine (e.g. Intel Paragon) has been reviewed and analyzed. The package contains about 45 software routines, some written in FORTRAN, and some in C-language, and forms the basis for parallel/distributed solutions of systems of linear equations encountered in many problems of scientific and engineering nature. The package, being studied by the Computer Applications Branch of the Analysis and Computation Division, may provide a significant computational resource for NASA scientists and engineers in parallel/distributed computing. Since the package is new and not well tested or documented, many of its underlying concepts and implementations were unclear; our task was to review, analyze, and critique the package as a step in the process that will enable scientists and engineers to apply it to the solution of their problems. All routines in the package were reviewed and analyzed. Underlying theory or concepts which exist in the form of published papers or technical reports, or memos, were either obtained from the author, or from the scientific literature; and general algorithms, explanations, examples, and critiques have been provided to explain the workings of these programs. Wherever the things were still unclear, communications were made with the developer (author), either by telephone or by electronic mail, to understand the workings of the routines. Whenever possible, tests were made to verify the concepts and logic employed in their implementations. A detailed report is being separately documented to explain the workings of these routines

Cathodic protection: introduction and recent developments

Corrosion of metals and alloys, on which the modern world depends completely, fromelectronic components to printed circuit boards, from nuts and bolts to bridges, fromautomobiles to railway parts to boiler tubes and nuclear reactors, is a practical problem oftremendous technological significance. Corrosion leads to colossal financial losses, whichare estimated to be 3-4% of GNP of a nation, not to speak of the loss of human lives,reputation, environment, aesthetics as well as shut-down and production losses. Of thevarious preventive measures like alloying, corrosion inhibitors, protective coatings, paints,design etc. to combat corrosion, only cathodic protection can guarantee 100% protection, ifproperly designed, executed and supplemented by protective coatings.The ABC ofcorrosion, principle of cathodic protection, with special reference to the development ofaluminium based sacrificial anodes like SUPERAL (medium output) and HOPAL (highoutput) as also insoluble anode like Sintered Magnetite Anode (SMA) in the NationalMetallurgical Laboratory in India, have been included in the paper. While the technology forthe sacrificial Al-based anodes has been transferred to two parties in India, SMA developedby NML is found to be the best because of its unique properties and low cost, compared to theconventionally used insoluble anodes. A cathodic protection system has also been designedand developed by NML with SMA, which is auto-controlled and very economical.AML hasalso successfully designed and executed the cathodic protection of the old water main lines(made from bare steel) in Calcutta, using Al-based sacrificial anodes.Merits and demerits ofgalvanic system compared to impressed current system and major research institutesengaged in corrosion area are listed Pertinent references have been cited for access to theoriginal and detailed literature

Photochemical Investigations of Ce(III)-V(V) System in Glasses

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Effect of Heat Stress on Milk Production and Composition in Murrah Buffaloes

Temperature humidity index (THI) is widely used to assess the effect of temperature and relative humidity on performance in animals. In summer the THI was between 74 - 89 with average value of 81.18. in winter months THI ranged between 49 -70 with the average of 60. The results showed a significant effect of heat stress on daily milk yield and milk composition. In the present study the daily milk yield decreases from 4.46 to 3.65kg, heat stress reduced milk yield by 18.2%. There was a significant effect of heat stress on milk composition. Heat stress significantly reduced milk fat content from 8.3% during the winter to 7.19% during the summer. Milk protein percentage significantly decreased as a result of summer heat stress (3.08 vs.2.9 %, respectively for the winter and summer). In the present study the SNF decreases from 9.08 to 9.05 %, heat stress reduced SNF % as the THI value went from > 74 to  83 in summer. Results showed that milk production is a function of THI. The negative slope of regression line indicates that milk production fat%, protein% and SNF% decreases as THI increases. This regression indicates that in general for each point increase in THI value. There was decrease in milk yield of 0.028kg per buffalo per day. Heat stress environments have been associated with depression in milk fat%, protein% and SNF%. There was decrease in milk fat of 0.046% per buffalo per day. There was also decrease in milk protein of 0.00014 % per buffalo per day. The decrease in milk SNF of 0.0047 % per buffalo per day

The Effects of Prosthesis Inertial Properties on Prosthetic Knee Moment and Hip Energetics Required to Achieve Able-bodied Kinematics

There is a major need in the developing world for a low-cost prosthetic knee that enables users to walk with able-bodied kinematics and low energy expenditure. To efficiently design such a knee, the relationship between the inertial properties of a prosthetic leg and joint kinetics and energetics must be determined. In this paper, using inverse dynamics, the theoretical effects of varying the inertial properties of an above-knee prosthesis on the prosthetic knee moment, hip power, and absolute hip work required for walking with ablebodied kinematics were quantified. The effects of independently varying mass and moment of inertia of the prosthesis, as well as independently varying the masses of each prosthesis segment, were also compared. Decreasing prosthesis mass to 25% of physiological leg mass increased peak late-stance knee moment by 43% and decreased peak swing knee moment by 76%. In addition, it reduced peak stance hip power by 26%, average swing hip power by 76%, and absolute hip work by 22%. Decreasing upper leg mass to 25% of its physiological value reduced absolute hip work by just 2%, whereas decreasing lower leg and foot mass reduced work by up to 22%, with foot mass having the greater effect. Results are reported in the form of parametric illustrations that can be utilized by researchers, designers, and prosthetists. The methods and outcomes presented have the potential to improve prosthetic knee component selection, facilitate ablebodied kinematics, and reduce energy expenditure for users of low-cost, passive knees in developing countries, as well as for users of advanced active knees in developed countries.MIT Department of Physics Pappalardo Program (Fellowship)Massachusetts Institute of Technology. Public Service CenterMassachusetts Institute of Technology. Research Support CommitteeNational Science Foundation (U.S.). Graduate Research Fellowship (Grant 1122374)MIT Tata Center for Technology and Desig

The Effects of the Inertial Properties of Above-Knee Prostheses on Optimal Stiffness, Damping, and Engagement Parameters of Passive Prosthetic Knees

Our research aims to design low-cost, high-performance, passive prosthetic knees for developing countries. In this study, we determine optimal stiffness, damping, and engagement parameters for a low-cost, passive prosthetic knee that consists of simple mechanical elements and may enable users to walk with the normative kinematics of able-bodied humans. Knee joint power was analyzed to divide gait into energy-based phases and select mechanical components for each phase. The behavior of each component was described with a polynomial function, and the coefficients and polynomial order of each function were optimized to reproduce the knee moments required for normative kinematics of able-bodied humans. Sensitivity of coefficients to prosthesis mass was also investigated. The knee moments required for prosthesis users to walk with able-bodied normative kinematics were accurately reproduced with a mechanical system consisting of a linear spring, two constant-friction dampers, and three clutches (R[superscript 2]=0.90 for a typical prosthetic leg). Alterations in upper leg, lower leg, and foot mass had a large influence on optimal coefficients, changing damping coefficients by up to 180%. Critical results are reported through parametric illustrations that can be used by designers of prostheses to select optimal components for a prosthetic knee based on the inertial properties of the amputee and his or her prosthetic leg

Evaluation of bacteriological diagnosis of smear positive pulmonary tubreculosis under programme conditions in three districts in the context of DOTS implementation in India

Objective: To study the smear and culture positivity rates in pulmonary tuberculosis patients declared as smear positive in the districts of North Arcot (Tamil Nadu), Raichur (Karnataka) and Wardha (Maharashtra) in India in order to evaluate the diagnosis of pulmonary tuberculosis at the field level under programme conditions. Methods: Two specimens of sputum from each of 320 patients in North Arcot, 314 patients in Raichur and 302 patients from Wardha district, all of whom had been reported as smear-positive at the field level, were examined by smear and culture. Findings: The proportion of specimens found to be smear-negative was 4.7% in North Arcot and 5.7% in Raichur as against 38.7% in Wardha. The proportions of culture negative specimens were 5.7% and 6.3% respectively in North Arcot and Raichur, while it was 35.6% at Wardha. The difference in the smear and culture negativity between Wardha and the other two districts was highly significant. Conclusions: The study revealed an unacceptably high level of false positives in sputum smear microscopy in the Wardha district. This could be attributed to the absence of systematic and intensive training in smear examination consequent to the non-implementation of the DOTS strategy in this district and a high standard of training offered in the RNTCP implemented districts

Corrosion resistant electrodeposited zinc coating from zinc dross

Electrodeposition of metals from aqueous solution produces a variety of metal alloy coatings. Zincalloy coatings are obtained by electrogalvanising of pure zinc. Properties of electrogalvanised steellike corrosion resistance spot weldability and adhesion are superior to hot-dip galvanisedsteel.Inthe present investigation, an attempt has been made to study electrodeposition of zinc from solidzinc drossas ananodic material on steel sheet acting as cathode and an aqueous bath containingdifferent concentration of Cl- ions, ammoniumsaltsandconducting substances at roomtemperature. An acid chloride bath was mainly used at different pH values. Very thin adherentand impervious coating was obtained on steel sheet. The zinc coating so obtained byelectrodepositionwas finally passivated to minimize white rust. X- ray diffraction, coatingthickness, atmospheric exposure test, electrochemical test, microhardness and cathodic efficiencyof zinc coated substrates were carried out. Salt -spray test on the coating was performed for 15days. Polarization experiments were carried out in 3.5 %NaCl solutionusingEG&G PARC-273Amodel Potentiostat Galvanostat. Open circuit potential (OCP) and corrosion potential (Ecorr) wererecorded. The process developed is very simple, economically viable and eco-friendly

Ventilatory responses to independent and combined hypoxia, hypercapnia and hypobaria in healthy pre-term-born adults.

Pre-term birth is associated with physiological sequelae that persist into adulthood. In particular, modulated ventilatory responsiveness to hypoxia and hypercapnia has been observed in this population. Whether pre-term birth per se causes these effects remains unclear. Therefore, we aimed to assess pulmonary ventilation and blood gases under various environmental conditions, comparing 17 healthy prematurely born individuals (mean ± SD; gestational age, 28 ± 2 weeks; age, 21 ± 4 years; peak oxygen uptake, 48.1 ± 11.2 ml kg <sup>-1</sup> min <sup>-1</sup> ) with 16 well-matched adults born at term (gestational age, 40 ± 1 weeks; age, 22 ± 2 years; peak oxygen uptake, 51.2 ± 7.7 ml kg <sup>-1</sup> min <sup>-1</sup> ). Participants were exposed to seven combinations of hypoxia/hypobaria (equivalent to ∼3375 m) and/or hypercapnia (3% CO <sub>2</sub> ), at rest for 6 min. Pulmonary ventilation, pulse oxygen saturation and the arterial partial pressures of O <sub>2</sub> and CO <sub>2</sub> were similar in pre-term and full-term individuals under all conditions. Higher ventilation in hypoxia compared to normoxia was only observed at terrestrial altitude, despite an equivalent (normobaric) hypoxic stimulus administered at sea level (0.138 ). Assessment of oscillations in key variables revealed that combined hypoxic hypercapnia induced greater underlying fluctuations in ventilation in pre-term individuals only. In general, higher pulse oxygen saturation fluctuations were observed with hypoxia, and lower fluctuations in end-tidal CO <sub>2</sub> with hypercapnia, despite similar ventilatory oscillations observed between conditions. These findings suggest that healthy prematurely born adults display similar overall ventilation to their term-born counterparts under various environmental stressors, but that combined ventilatory stimuli could induce an irregular underlying ventilatory pattern. Moreover, barometric pressure may be an important factor when assessing ventilatory responsiveness to moderate hypoxic stimuli. KEY POINTS: Evidence exists for unique pulmonary and respiratory function under hypoxic conditions in adult survivors of pre-term birth. Whether pre-term birth per se causes these differences requires a comparison of conventionally healthy prematurely born adults with an appropriately matched sample of term-born individuals. According to the present data, there is no difference between healthy pre-term and well-matched term-born individuals in the magnitude of pulmonary ventilation or arterial blood gases during independent and combined hypobaria, hypoxia and hypercapnia. Terrestrial altitude (hypobaria) was necessary to induce differences in ventilation between normoxia and a hypoxic stimulus equivalent to ∼3375 m of altitude. Furthermore, peak power in pulse oxygen saturation was similar between hypobaric normoxia and normobaric hypoxia. The observed similarities between groups suggest that ventilatory regulation under various environmental stimuli is not impaired by pre-term birth per se. Instead, an integrated combination of neonatal treatment strategies and cardiorespiratory fitness/disease status might underlie previously observed chemosensitivity impairments

Quantum plasmons with optical-range frequencies in doped few-layer graphene

Although plasmon modes exist in doped graphene, the limited range of doping achieved by gating restricts the plasmon frequencies to a range that does not include the visible and infrared. Here we show, through the use of first-principles calculations, that the high levels of doping achieved by lithium intercalation in bilayer and trilayer graphene shift the plasmon frequencies into the visible range. To obtain physically meaningful results, we introduce a correction of the effect of plasmon interaction across the vacuum separating periodic images of the doped graphene layers, consisting of transparent boundary conditions in the direction perpendicular to the layers; this represents a significant improvement over the exact Coulomb cutoff technique employed in earlier works. The resulting plasmon modes are due to local field effects and the nonlocal response of the material to external electromagnetic fields, requiring a fully quantum mechanical treatment. We describe the features of these quantum plasmons, including the dispersion relation, losses, and field localization. Our findings point to a strategy for fine-tuning the plasmon frequencies in graphene and other two-dimensional materials.MIT/Army Institute for Soldier Nanotechnologies (Contract W911NF-13-D-0001