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In this work, the structural, electronic, and dynamical properties of novel half-Heusler (HH) alloy AlNiP are studied by applying first-principles density functional theory (DFT). The structural properties of AlNiP in the LiAlSi-type crystal structure with three different phases (α-phase, β-phase, and γ-phase) in different atomic arrangements are explored. The 'γ-phase' of AlNiP is found to be energetically stable among three. Moreover, the calculated ferromagnetic (FM), non-magnetic (NM) and anti-ferromagnetic (AFM) state for AlNiP favours the 'NM' state. The overlapping of the valence band and conduction band signifies the metallic characteristics of the alloy at 0 GPa and high pressure 38 GPa. The lattice dynamics of novel HH alloy AlNiP have also been investigated by applying DFT followed by density functional perturbation theory (DFPT). The phonon calculation suggests the face-centred cubic phase of HH alloy AlNiP is stable at ambient condition and also at high pressure of 38 GPa. For the confirmation of this stability, the phonon density of states has also been calculated at zero and higher value of pressure. The calculated results are further interpreted in the light of the similar type of alloys. [ABSTRACT FROM AUTHOR]

It is believed that the effectual scattering by earth-abundant Al nanoparticles in combination with photoelectric conversion-efficient GaAs material may help for cost-effective solar cells. Al nanoparticles of various radii embedded at different depths in a Ta2O5-coated GaAs semiconductor have been studied by finite-difference time-domain method for their influence towards spectral absorption rate and photocurrent in GaAs solar cells. The calculated spectral absorption rate and photocurrent show a significant enhancement at the optimal depth for a particular radius of Al nanoparticles, which is explained on the basis of surface plasmon resonance. Al nanoparticles of radius 80 nm embedded just below the antireflection layer of Ta2O5 result a maximum spectral absorption rate of 0.95 that leads to a photocurrent of 30.43 mA/cm2. [ABSTRACT FROM AUTHOR]

In the present work, a thin film solar cell structure consisting of thin GaAs layer, metallic nanoparticle array and aluminum back reflector is proposed and studied to calculate optical absorption and current density using finite difference time domain (FDTD) numerical simulation method. Simulation results show that in comparison to other metallic nanoparticles, aluminum nanoparticles have strong plasmonic scattering effect at optimized period of 100nm and radius 40nm to improve the efficiency of thin film GaAs solar cells through enhancement of current density integrated over solar spectrum by 31% compared to bare thin film GaAs solar cells. [ABSTRACT FROM PUBLISHER]

Direct estimation of maximal aerobic power is an intricate procedure and requires the facility of a well-equipped laboratory. Attempts have been made, therefore, to develop linear and nonlinear regression equations for its indirect assessment, but many biomedical scientists have difficulty in using these statistically based equations. Bearing this in mind, this paper constructs two nomograms for predicting maximal aerobic power. The first nomogram, based on cardiorespiratory strains, is more precise but requires the facility of an equipped laboratory owing to the involvement of some physiological variables; the second nomogram, based on the two variables body weight and time for a 3.2 km run, does not require any laboratory facility for prediction of maximal aerobic power. Both nomograms have limited validity. The first is most reliable in the range 1.83-3.28 l.min−1; the second is best in the range 1.76-3.06 l.min−1 of maximal aerobic power. [ABSTRACT FROM PUBLISHER]

Indirect measurement of energy expenditure during work is carried oul from either minuie ventilation or heart rate during the activity under consideration. In the present study a multiple linear regression equation has been evolved for estimating energy expenditure from minute ventilation and heart rate during various grades of submaximal work on a bicycle ergomcler on 55 human subjects involving 165 observations. The product-moment correlations of minute ventilation and heart rate with energy expenditure were found to be 0 74 and 0 59 respectively. The multiple correlation coefficient between observed energy expenditure and both minute ventilation and heart rate was 0.80 (p < 0.001). This is significantly (p < 0. 05)greater than the individual correlation coefficient for energy expenditure and minute ventilation alone. It is concluded that a combination of minute ventilation and heart rate is a better predictor of energy expenditure than either of the two variables used singly. A nomogram has been constructed for this purpose. [ABSTRACT FROM PUBLISHER]