1,979 research outputs found
A noncontact measurement technique for the density and thermal expansion coefficient of solid and liquid materials
A noncontact measurement technique for the density and the thermal expansion coefficient of refractory materials in their molten as well as solid phases is presented. This technique is based on the video image processing of a levitated sample. Experiments were performed using the high-temperature electrostatic levitator (HTESL) at the Jet Propulsion Laboratory in which 2â3 mm diam samples can be levitated, melted, and radiatively cooled in vacuum. Due to the axisymmetric nature of the molten samples when levitated in the HTESL, a rather simple digital image analysis can be employed to accurately measure the volumetric change as a function of temperature. Density and the thermal expansion coefficient measurements were made on a pure nickel sample to test the accuracy of the technique in the temperature range of 1045â1565 °C. The result for the liquid phase density can be expressed by rho=8.848+(6.730Ă10^â4)ĂT (°C) g/cm^3 within 0.8% accuracy, and the corresponding thermal expansion coefficient can be expressed by beta=(9.419Ă10^â5) â(7.165Ă10^â9)ĂT (°C) K^â1 within 0.2% accuracy
GENETIC VARIABILITY AMONG CATTLE BREEDS FOR BEEF PRODUCTION
Between-breed variation in body weight, food intake, carcass composition, milk yield, efficiency of food conversion during growth and maintenance efficiency in adult cattle was examined in a multibreed experiment at the AFRC Animal Breeding Research Organisation. Females from 11 beef , 8 dual-purpose and 6 dairy breeds were fed a complete pelleted diet (AA6) ad libitum from weaning at 12 weeks of age until the birth of their third calf. Females were mated by AI to produce both purebred and crossbred progeny which were reared under the same conditions and slaughtered at either 24, 48 or 72 weeks of age. In addition, non-pregnant, non-lactating mature females from two beef breeds, two dairy breeds and one dual purpose breed were fed for prolonged periods on fixed levels of the same AA6 diet until an equilibrium body weight had been attained. There was significant variation among breeds for body weight, cumulated intake and cumulated food efficiency over the age range of 12 to 72 weeks. At 12 weeks of age the between-breed variation as a proportion of the total (t) was 0.71 for body weight, 0.62 for cumulated intake and 0.15 for cumulated food efficiency. Breed and sex had Significant effects on carcass composition at all three age of 24, 48 and 72 weeks. Heterosis in carcass composition although significant at 24 weeks declined at subsequent ages. Beef breeds when compared with dairy breeds had on average daily lactation yields that were half as high, total lactation yields that were 1/3 as high and lactation lengths that were 2/3 as long. Maintenance efficiency in mature cattle varied with potential milk yield, beef breeds being about 20% more efficient than dairy breeds
GENETIC VARIABILITY AMONG CATTLE BREEDS FOR BEEF PRODUCTION
Between-breed variation in body weight, food intake, carcass composition, milk yield, efficiency of food conversion during growth and maintenance efficiency in adult cattle was examined in a multibreed experiment at the AFRC Animal Breeding Research Organisation. Females from 11 beef , 8 dual-purpose and 6 dairy breeds were fed a complete pelleted diet (AA6) ad libitum from weaning at 12 weeks of age until the birth of their third calf. Females were mated by AI to produce both purebred and crossbred progeny which were reared under the same conditions and slaughtered at either 24, 48 or 72 weeks of age. In addition, non-pregnant, non-lactating mature females from two beef breeds, two dairy breeds and one dual purpose breed were fed for prolonged periods on fixed levels of the same AA6 diet until an equilibrium body weight had been attained. There was significant variation among breeds for body weight, cumulated intake and cumulated food efficiency over the age range of 12 to 72 weeks. At 12 weeks of age the between-breed variation as a proportion of the total (t) was 0.71 for body weight, 0.62 for cumulated intake and 0.15 for cumulated food efficiency. Breed and sex had Significant effects on carcass composition at all three age of 24, 48 and 72 weeks. Heterosis in carcass composition although significant at 24 weeks declined at subsequent ages. Beef breeds when compared with dairy breeds had on average daily lactation yields that were half as high, total lactation yields that were 1/3 as high and lactation lengths that were 2/3 as long. Maintenance efficiency in mature cattle varied with potential milk yield, beef breeds being about 20% more efficient than dairy breeds
Theology and Ecology in a Time of Pandemic
As the sequential stages of the 2020 COVID-19 pandemic have unfolded, so have its complexities. What initially presented as a health emergency, has revealed itself to be a phenomenon of many facets. As the situation continues to advance, the question for many is whether the crisis will be grasped as an opportunity to address deep structural, ecological and social challenges. This introductory chapter briefly addresses why and how the fields of ecology and theology can play an important and vital role in addressing the challenges and its transformative possibilities presented by the COVID-19 pandemic
Multi-Disciplinary Hands-On Desktop Learning Modules and Modern Pedagogies
Our teamâs research focuses on fundamental problems in undergraduate education in terms of how to expand use of well researched, yet still ânewâ, teaching pedagogies of âsensingâ or âhands-onâ, âactiveâ and âproblem-based learningâ within engineering courses. It is now widely accepted that traditional lectures ARE NOT best for students â yet that is what the community almost universally does.
To address this issue we are developing new Desktop Learning Modules (DLMs) that contain miniaturized processes with a uniquely expandable electronic system to contend with known sensor systems/removable cartridges, as well as, unknown expansions to the project. We have shown that miniaturized mimics of industrial-scale equipment produce process data that agree with correlations developed for large-scale equipment. We are now adapting concepts shown efficacious in a single chemical engineering course to a variety of engineering classes within civil, mechanical, bio- and electrical engineering. Some examples of new hands-on learning applications in chemical engineering include a boiler / condenser and evaporative and shell & tube heat exchangers.
In bioengineering, we are developing prognostic devices for separating Prostate Cancer Tumor Cells (PCTCs) from blood, sensing for the presence of PCTCs, a thermoregulation simulated limb cartridge for studying kinematics of heat flow and heat distribution in human extremities, and immunoaffinity neuron-like ion selective electrodes. In civil engineering, the DLMs illustrate open channel flow units and a solar powered Rankine cycle is underway in mechanical engineering. We are implementing DLMs along with team learning pedagogy. In this paper we will present technical aspects surrounding development of a large number of new learning cartridges. While the assessment strategies being developed are broadly applicable we will just present one instance, with the civil engineering cartridge, of the identification of misconceptions and experimental design for assessing the impact of the DLM on learning. The assessment includes a pre- and post-test assessment to determine improvement in understanding basic concepts and persistence and/or repair of misconceptions
Immunoadsorption of agonistic autoantibodies against α1-adrenergic receptors in patients with mild to moderate dementia
Dementia has been shown to be associated with agonistic autoantibodies. The deleterious action of autoantibodies on the {alpha}1-adrenergic receptor for brain vasculature has been demonstrated in animal studies. In the current study, 169 patients with dementia were screened for the presence of agonistic autoantibodies. 47% of patients suffering from mild to moderate Alzheimer's disease and/or vascular dementia carried these autoantibodies. Eight patients positive for autoantibodies underwent immunoadsorption. Patients treated on four consecutive days were subsequently negative for autoantibodies and displayed stabilization of cognitive and mental condition during 12-18 months' follow-up. In patients treated for 2-3 days, autoantibodies were reduced by only 78%. They suffered a rebound of autoantibodies during follow-up, benefited from immunoadsorption too, but their mental parameters worsened. We provide first data on the clinical relevance of agonistic autoantibodies in dementia and show that immunoadsorption is safe and efficient in removing autoantibodies with overall benefits for patients
A noncontact measurement technique for the density and thermal expansion coefficient of solid and liquid materials
MRI T2 and T1Ï relaxation in patients at risk for knee osteoarthritis: A systematic review and meta-analysis
© 2019 The Author(s). Background: Magnetic resonance imaging (MRI) T2 and T1Ï relaxation are increasingly being proposed as imaging biomarkers potentially capable of detecting biochemical changes in articular cartilage before structural changes are evident. We aimed to: 1) summarize MRI methods of published studies investigating T2 and T1Ï relaxation time in participants at risk for but without radiographic knee OA; and 2) compare T2 and T1Ï relaxation between participants at-risk for knee OA and healthy controls. Methods: We conducted a systematic review of studies reporting T2 and T1Ï relaxation data that included both participants at risk for knee OA and healthy controls. Participant characteristics, MRI methodology, and T1Ï and T2 relaxation data were extracted. Standardized mean differences (SMDs) were calculated within each study. Pooled effect sizes were then calculated for six commonly segmented knee compartments. Results: 55 articles met eligibility criteria. There was considerable variability between scanners, coils, software, scanning protocols, pulse sequences, and post-processing. Moderate risk of bias due to lack of blinding was common. Pooled effect sizes indicated participants at risk for knee OA had lengthened T2 relaxation time in all compartments (SMDs from 0.33 to 0.74; p \u3c 0.01) and lengthened T1Ï relaxation time in the femoral compartments (SMD from 0.35 to 0.40; p \u3c 0.001). Conclusions: T2 and T1Ï relaxation distinguish participants at risk for knee OA from healthy controls. Greater standardization of MRI methods is both warranted and required for progress towards biomarker validation
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