The Attitudes of Men Students Toward the Required Physical Education Program at South Dakota State College

The purpose of this investigation was to determine the attitude of male students at South Dakota State College toward the required physical education program. Through this study the author hoped to ascertain the attitude of the male student toward physical education in respect to the total required program, its value to the student, academic credit, facilities, instruction, educational needs, and the activities most desired by the male student. It was hoped that such a study might help to improve the required program of physical education. The descriptive method of research was used in this study in the form of a questionnaire returned by 524 respondents. High school experience in physical education had very little influence on the attitude toward physical education at State College. Benefiting physically was rated second followed b y benefitting mentally, emotionally, and morally in that order. A high percentage of the total sample indicated they enjoyed physical education at State College, and a favorable percent was recorded by the total sample toward having physical education required at State College

Using bond-length dependent transferable force constants to predict vibrational entropies in Au-Cu, Au-Pd, and Cu-Pd alloys

A model is tested to rapidly evaluate the vibrational properties of alloys with site disorder. It is shown that length-dependent transferable force constants exist, and can be used to accurately predict the vibrational entropy of substitutionally ordered and disordered structures in Au-Cu, Au-Pd, and Cu-Pd. For each relevant force constant, a length- dependent function is determined and fitted to force constants obtained from first-principles pseudopotential calculations. We show that these transferable force constants can accurately predict vibrational entropies of L1$_{2}$-ordered and disordered phases in Cu$_{3}$Au, Au$_{3}$Pd, Pd$_{3}$Au, Cu$_{3}$Pd, and Pd$_{3}$Au. In addition, we calculate the vibrational entropy difference between L1$_{2}$-ordered and disordered phases of Au$_{3}$Cu and Cu$_{3}$Pt.Comment: 9 pages, 6 figures, 3 table

First principles based design and experimental evidence for a ZnO-based ferromagnet at room temperature

The introduction of ferromagnetic order in ZnO results in a transparent piezoelectric ferromagnet and further expands its already wide range of applications into the emerging field of spintronics. Through an analysis of density functional calculations we determine the nature of magnetic interactions for transition metals doped ZnO and develop a physical picture based on hybridization, superexchange, and double exchange that captures chemical trends. We identify a crucial role of defects in the observed weak and preparation sensitive ferromagnetism in ZnO:Mn and ZnO:Co. We predict and explain codoping of Li and Zn interstitials to both yield ferromagnetism in ZnO:Co, in contrast with earlier insights, and verify it experimentally

Charge redistribution at Pd surfaces: ab initio grounds for tight-binding interatomic potentials

A simplified tight-binding description of the electronic structure is often necessary for complex studies of surfaces of transition metal compounds. This requires a self-consistent parametrization of the charge redistribution, which is not obvious for late transition series elements (such as Pd, Cu, Au), for which not only d but also s-p electrons have to be taken into account. We show here, with the help of an ab initio FP-LMTO approach, that for these elements the electronic charge is unchanged from bulk to the surface, not only per site but also per orbital. This implies different level shifts for each orbital in order to achieve this orbital neutrality rule. Our results invalidate any neutrality rule which would allow charge redistribution between orbitals to ensure a common rigid shift for all of them. Moreover, in the case of Pd, the power law which governs the variation of band energy with respect to coordination number, is found to differ significantly from the usual tight-binding square root.Comment: 6 pages, 2 figures, Latex; Phys.Rev. B 56 (1997

Nucleation of Al3Zr and Al3Sc in aluminum alloys: from kinetic Monte Carlo simulations to classical theory

Zr and Sc precipitate in aluminum alloys to form the compounds Al3Zr and Al3Sc which for low supersaturations of the solid solution have the L12 structure. The aim of the present study is to model at an atomic scale this kinetics of precipitation and to build a mesoscopic model based on classical nucleation theory so as to extend the field of supersaturations and annealing times that can be simulated. We use some ab-initio calculations and experimental data to fit an Ising model describing thermodynamics of the Al-Zr and Al-Sc systems. Kinetic behavior is described by means of an atom-vacancy exchange mechanism. This allows us to simulate with a kinetic Monte Carlo algorithm kinetics of precipitation of Al3Zr and Al3Sc. These kinetics are then used to test the classical nucleation theory. In this purpose, we deduce from our atomic model an isotropic interface free energy which is consistent with the one deduced from experimental kinetics and a nucleation free energy. We test di erent mean-field approximations (Bragg-Williams approximation as well as Cluster Variation Method) for these parameters. The classical nucleation theory is coherent with the kinetic Monte Carlo simulations only when CVM is used: it manages to reproduce the cluster size distribution in the metastable solid solution and its evolution as well as the steady-state nucleation rate. We also find that the capillary approximation used in the classical nucleation theory works surprisingly well when compared to a direct calculation of the free energy of formation for small L12 clusters.Comment: submitted to Physical Review B (2004

Biorefining of wheat straw:accounting for the distribution of mineral elements in pretreated biomass by an extended pretreatment–severity equation

BACKGROUND: Mineral elements present in lignocellulosic biomass feedstocks may accumulate in biorefinery process streams and cause technological problems, or alternatively can be reaped for value addition. A better understanding of the distribution of minerals in biomass in response to pretreatment factors is therefore important in relation to development of new biorefinery processes. The objective of the present study was to examine the levels of mineral elements in pretreated wheat straw in response to systematic variations in the hydrothermal pretreatment parameters (pH, temperature, and treatment time), and to assess whether it is possible to model mineral levels in the pretreated fiber fraction. RESULTS: Principal component analysis of the wheat straw biomass constituents, including mineral elements, showed that the recovered levels of wheat straw constituents after different hydrothermal pretreatments could be divided into two groups: 1) Phosphorus, magnesium, potassium, manganese, zinc, and calcium correlated with xylose and arabinose (that is, hemicellulose), and levels of these constituents present in the fiber fraction after pretreatment varied depending on the pretreatment-severity; and 2) Silicon, iron, copper, aluminum correlated with lignin and cellulose levels, but the levels of these constituents showed no severity-dependent trends. For the first group, an expanded pretreatment-severity equation, containing a specific factor for each constituent, accounting for variability due to pretreatment pH, was developed. Using this equation, the mineral levels could be predicted with R(2) > 0.75; for some with R(2) up to 0.96. CONCLUSION: Pretreatment conditions, especially pH, significantly influenced the levels of phosphorus, magnesium, potassium, manganese, zinc, and calcium in the resulting fiber fractions. A new expanded pretreatment-severity equation is proposed to model and predict mineral composition in pretreated wheat straw biomass