Directional solidification of flake and nodular cast iron during KC-135 low-g maneuvers

Alloys solidified in a low-gravity environment can, due to the elimination of sedimentation and convection, form unique and often desirable microstructures. One method of studying the effects of low-gravity (low-g) on alloy solidification was the use of the NASA KC-135 aircraft flying repetitive low-g maneuvers. Each maneuver gives from 20 to 30 seconds of low-g which is between about 0.1 and 0.001 gravity. A directional solidification furnace was used to study the behavior of off eutectic composition case irons in a low-g environment. The solidification interface of hypereutectic flake and spheroidal graphite case irons was slowly advanced through a rod sample, 5 mm in diameter. Controlled solidification was continued through a number of aircraft parabolas. The known solidification rate of the sample was then correlated with accelerometer data to determine the gravity level during solidification for any location of the sample. The thermal gradient and solidification rate were controlled independently. Samples run on the KC-135 aircraft exhibited bands of coarser graphite or of larger nodules usually corresponding to the regions solidified under low-g. Samples containing high phosphorous (used in order to determine the eutectic cell) exhibited larger eutectic cells in the low-g zone, followed by a band of coarser graphite

Preliminary science report on the directional solidification of hypereutectic cast iron during KC-135 low-G maneuvers

An ADSS-P directional solidification furnace was reconfigured for operation on the KC-135 low-g aircraft. The system offers many advantages over quench ingot methods for study of the effects of sedimentation and convection on alloy formation. The directional sodification furnace system was first flown during the September 1982 series of flights. The microstructure of the hypereutectic cast iron sample solidified on one of these flights suggests a low-g effect on graphite morphology. Further experiments are needed to ascertain that this effect is due to low-gravity and to deduce which of the possible mechanisms is responsible for it

A Survey of Medical Schools\u27 Disability Curricula

It is a well established problem that people with disabilities (PWD), as with many other groups disadvantaged by social inequities, often receive suboptimal care from health care providers. The root cause of this inequity in care can be traced to a lack of training in dealing with PWD for health care providers. Barriers result from issues of communication, knowledge of resources available, access to clinics/hospitals, difficulty using diagnostic equipment (exam tables, scales, mammography, etc) and attitudes towards PWD. Despite numerous reports outlining this issue and calls to action to address deficiencies in the care of PWD, few medical schools currently address the care of patients with disabilities in their curriculum. This poster provides a survey of disability curricula in medical schools and a summary of their content/approach and effectiveness.https://digitalrepository.unm.edu/hslic-posters-presentations/1058/thumbnail.jp

Experiment Checkout During Postmanufacturing Checkout of the Apollo Telescope Mount

The postmanufacturing checkout of the Apollo Telescope Mount (ATM) offers a real challenge for both the technology of today and the technology of tomorrow. The objective of this discussion is to explain the sequence of tests to be performed on t he ATM experiments to assure flight readiness, based on current preliminary planning information. Checkout means the verification of all operating systems. The challenge is to define tests today to check out experiments that will be built and flown tomorrow. The engineering state-ofthe art is identified today for a vehicle, including the experiments, that is scheduled to fly in 1972

On local convergence of stochastic global optimization algorithms

In engineering optimization with continuous variables, the use of Stochastic Global Optimization (SGO) algorithms is popular due to the easy availability of codes. All algorithms have a global and local search character, where the global behaviour tries to avoid getting trapped in local optima and the local behaviour intends to reach the lowest objective function values. As the algorithm parameter set includes a final convergence criterion, the algorithm might be running for a while around a reached minimum point. Our question deals with the local search behaviour after the algorithm reached the final stage. How fast do practical SGO algorithms actually converge to the minimum point? To investigate this question, we run implementations of well known SGO algorithms in a final local phase stage.- This paper has been supported by The Spanish Ministry (RTI2018-095993-B-I00) in part financed by the European Regional Development Fund (ERDF) and by FCT Fundacao para a Ciencia e Tecnologia within the Project Scope: UIDB/00319/2020

Origin and implications of the observed rhombohedral phase in nominally tetragonal Pb(Zr\u3csub\u3e0.35\u3c/sub\u3eTi\u3csub\u3e0.65\u3c/sub\u3e)O\u3csub\u3e3\u3c/sub\u3e thin films

The structural and electrical properties of Pb(Zr0.35Ti0.65)O3 (PZT) thin films ranging in thickness from 700 to 4000 Å have been investigated. These (001)/(100)-textured films were grown by metalorganic chemical vapor deposition on (111)-textured Ir bottom electrodes. It was observed that, in the as-deposited state, the thinnest PZT films are rhombohedral even though bulk PZT of this composition should be tetragonal. Thicker films have a layered structure with tetragonal PZT at the surface and rhombohedral PZT at the bottom electrode interface. In this article we investigate the origin of this structure and its effect of the ferroelectric and dielectric properties of PZT capacitors. It has been suggested that thin films stresses can affect the phase stability regions of single domain PZT. This possibility has been investigated by piezoresponse microscopy and thin film stress measurements. In the as-deposited state the majority of PZT grains contain a single ferroelastic domain, whereas after a high temperature anneal, a large fraction of the grains contain several ferroelastic domains. Wafer curvature measurements in combination with x-ray diffraction stress measurements in the Ir bottom electrode showed that the as-deposited PZT films are, within experimental error, stress free at room temperature. Landau–Ginbzurg–Devonshire formalism was used to explain the origin of the rhombohedral phase as a result of substrate constraint on single domain PZT grains. Annealing was found to affect the relative volume fractions of the rhombohedral and tetragonal phases and the electrical properties of PZT films. Intermediate temperature anneals increased the volume fraction of the rhombohedral phase and the coercive field extracted from the polarization-electric field hysteresis loops. After a high temperature anneal (650 °C) the majority of the grains transformed into a polydomain state, decreasing the volume fraction of the rhombohedral phase and the coercive field. If the high temperature anneal was performed after deposition of the top electrode, the coercive field became independent of the PZT thickness

Predicting aflatoxin content in peanuts using ambient temperature, soil temperature and soil moisture content during pod development

Higher than acceptable aflatoxin levels in peanut kernels (Arachis hypogaea L.) and related products is a worldwide food safety concern. Strict regulatory standards by major importers of peanuts limit the marketability of peanuts for many developing tropical countries including Zambia. The incidence of preharvest aflatoxins is strongly linked to soil and weather conditions during pod-development. This study aimed to formulate statistical models to predict total aflatoxin content in peanut kernels using selected environmental factors during pod development. Field experiments were conducted for two years during which the peanut crop was exposed to 84 combinations of ambient temperature, soil temperature and soil moisture content measured during the last 30 days of pod development. These data were used to formulate regression models to predict total aflatoxin content in peanut kernels. Simple linear regression models had R2 values of 0.30 for maximum ambient temperature, 0.24 for soil temperature and 0.38 for soil moisture content. Combining soil moisture content and soil temperature in a multivariate regression model could explain 54% of the variation in total aflatoxin content while a combination of soil moisture content and maximum ambient temperature could only explain 46% of the variation in total aflatoxin content

Equilibrium Sampling From Nonequilibrium Dynamics

We present some applications of an Interacting Particle System (IPS) methodology to the field of Molecular Dynamics. This IPS method allows several simulations of a switched random process to keep closer to equilibrium at each time, thanks to a selection mechanism based on the relative virtual work induced on the system. It is therefore an efficient improvement of usual non-equilibrium simulations, which can be used to compute canonical averages, free energy differences, and typical transitions paths

Lactate dehydrogenase expression modulates longevity and neurodegeneration in Drosophila melanogaster

Lactate dehydrogenase (LDH) catalyzes the conversion of glycolysis-derived pyruvate to lactate. Lactate has been shown to play key roles in brain energetics and memory formation. However, lactate levels are elevated in aging and Alzheimer\u27s disease patients, and it is not clear whether lactate plays protective or detrimental roles in these contexts. Here we show that Ldh transcript levels are elevated and cycle with diurnal rhythm in the heads of aged flies and this is associated with increased LDH protein, enzyme activity, and lactate concentrations. To understand the biological significance of increased Ldh gene expression, we genetically manipulated Ldh levels in adult neurons or glia. Overexpression of Ldh in both cell types caused a significant reduction in lifespan whereas Ldh down-regulation resulted in lifespan extension. Moreover, pan-neuronal overexpression of Ldh disrupted circadian locomotor activity rhythms and significantly increased brain neurodegeneration. In contrast, reduction of Ldh in neurons delayed age-dependent neurodegeneration. Thus, our unbiased genetic approach identified Ldh and lactate as potential modulators of aging and longevity in flies

Circadian deep sequencing reveals stress-response genes that adopt robust rhythmic expression during aging

Disruption of the circadian clock, which directs rhythmic expression of numerous output genes, accelerates aging. To enquire how the circadian system protects aging organisms, here we compare circadian transcriptomes in heads of young and old Drosophila melanogaster. The core clock and most output genes remained robustly rhythmic in old flies, while others lost rhythmicity with age, resulting in constitutive over- or under-expression. Unexpectedly, we identify a subset of genes that adopted increased or de novo rhythmicity during aging, enriched for stress-response functions. These genes, termed late-life cyclers, were also rhythmically induced in young flies by constant exposure to exogenous oxidative stress, and this upregulation is CLOCK-dependent. We also identify age-onset rhythmicity in several putative primary piRNA transcripts overlapping antisense transposons. Our results suggest that, as organisms age, the circadian system shifts greater regulatory priority to the mitigation of accumulating cellular stress