15,800 research outputs found
Evidence for electron-phonon interaction in FeMSb (M=Co, Cr) single crystals
We have measured polarized Raman scattering spectra of the
FeCoSb and FeCrSb (00.5)
single crystals in the temperature range between 15 K and 300 K. The highest
energy symmetry mode shows significant line asymmetry due to phonon
mode coupling width electronic background. The coupling constant achieves the
highest value at about 40 K and after that it remains temperature independent.
Origin of additional mode broadening is pure anharmonic. Below 40 K the
coupling is drastically reduced, in agreement with transport properties
measurements. Alloying of FeSb with Co and Cr produces the B mode
narrowing, i.e. weakening of the electron-phonon interaction. In the case of
A symmetry modes we have found a significant mode mixing
Developing parametric human models representing various vulnerable populations in motor vehicle crashes
Children, small female, elderly, and obese occupants are vulnerable populations and may sustain increased risk of death and serious injury in motor-vehicle crashes compared with mid-size young male occupants. Unfortunately, current injury assessment tools do not account for immature and growing body structures for children, nor the body shape and composition changes that are thought make female/aging/obese adults more vulnerable. The greatest opportunity to broaden crash protection to encompass all vehicle occupants lies in improved, parametric human models that can represent a wide range of human attributes. In this study, a novel approach to develop such models is proposed. The method includes 1) developing statistical skeleton and human body surface contour models based on medical images and body scan data using Mimics and a series of statistical methods, and 2) linking the statistical geometry model to a baseline human finite element (FE) model through an automated mesh morphing algorithm using radial basis functions, so that the FE model can represent population variability. Examples of using this approach to develop parametric pediatric head model, adult thorax and lower extremity models, and whole-body human models representing various populations were represented. The method proposed in this study enables future safety design optimizations targeting at various vulnerable populations that cannot be considered with current injury assessment tools.http://deepblue.lib.umich.edu/bitstream/2027.42/113667/1/103204.pdf-
A rare presentation of the Klinefelter's syndrome
A 16 years old boy with Chronic Renal Failure (CRF) was not suspected of having Klinefelter's syndrome until he complained of painful gynecomastia. He was under haemodialysis for 2 years. At first, he was in an approximately full pubertal development (P5, G5), but he had a small and a firm testis (length 2.2cm) and some degree of facial male pattern hair. He also had a decreased upper to lower body segment ratio and despite having chronic renal failure, he was taller than his parents and siblings. His laboratory tests showed high levels of FSH and normal levels of LH and testosterone. With regards to all these findings, we suspected that there might be an occult Klinefelter's syndrome. So, we made his karyotype that showed a 47XXY pattern. Because there are only a few number of cases that have occult Klinefelter's syndrome in the basis of chronic renal failure, we decided to report this case
Determining the crystal-field ground state in rare earth Heavy Fermion materials using soft-x-ray absorption spectroscopy
We infer that soft-x-ray absorption spectroscopy is a versatile method for
the determination of the crystal-field ground state symmetry of rare earth
Heavy Fermion systems, complementing neutron scattering. Using realistic and
universal parameters, we provide a theoretical mapping between the polarization
dependence of Ce spectra and the charge distribution of the Ce
states. The experimental resolution can be orders of magnitude larger than the
crystal field splitting itself. To demonstrate the experimental
feasibility of the method, we investigated CePdSi, thereby settling an
existing disagreement about its crystal-field ground state
Effect of Hetrovalent substitution at Mn site on the Magnetic and Transport Properties of LaSrMnO
Magnetic and transport properties of Ti substituted
LaSrMnO are drastically affected with a change in
preparation conditions. Low temperature infra-red absorption measurements
reveal that this is perhaps due to inhomogeniety in substitution of Ti
on Mn sites. It is found that, in the high temperature annealed samples, the
substitution of Ti supresses the double exchange interaction due to the
formation of Mn-O-Ti chains. While in the low temperature
annealed case substitution of Ti causes formation of isolated ferromagnetic
clusters linked to each other by a variable range hopping polaron.Comment: 11 pages, 8 figures, accepted in J. Magn. Magn. Magn. Mate
Finite-size scaling for non-linear rheology of fluids confined in a small space
We perform molecular dynamics simulations in order to examine the rheological
transition of fluids confined in a small space. By performing finite-size
scaling analysis, we demonstrate that this rheological transition results from
the competition between the system size and the length scale of cooperative
particle motion.Comment: 4pages, 8 figure
Development and validation of statistical models of femur geometry for use with parametric finite element models
Statistical models from a previous study that predict male and female femur geometry as functions of age, body mass index (BMI), and femur length were updated as part of an effort to develop lower-extremity finite element models with geometries that are parametric with subject characteristics. The process for updating these models involved extracting femur geometry from clinical CT scans of an additional 8 men and 36 women (previous models used CT scans from 62 men and 36 women for a new total of 70 men and 72 women), using all of the scans for fitting a template finite element femur mesh to the surface geometry of each patient, and then programmatically determining thickness at each nodal location. Principal component analysis was then performed on the thickness and geometry nodal coordinates, and linear regression models were developed to predict principal component scores as functions of age, BMI, and femur length. The results from the updated models were compared to the previous study, and the only improvement was in the R2 value for the female models (0.74 to 0.82). The largest differences between the original models and the previous models occurred in the ends of the femur, where the largest errors in model predictions occurred.National Highway Traffic Safety Administrationhttp://deepblue.lib.umich.edu/bitstream/2027.42/116208/1/103222.pdfDescription of 103222.pdf : Final repor
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