Shot noise in diffusive ferromagnetic metals

We show that shot noise in a diffusive ferromagnetic wire connected by tunnel contacts to two ferromagnetic electrodes can probe the intrinsic density of states and the extrinsic impurity scattering spin-polarization contributions in the polarization of the wire conductivity. The effect is more pronounced when the electrodes are perfectly polarized in opposite directions. While in this case the shot noise has a weak dependence on the impurity scattering polarization, it is strongly affected by the polarization of the density of states. For a finite spin-flip scattering rate the shot noise increases well above the normal state value and can reach the full Poissonian value when the density of states tends to be perfectly polarized. For the parallel configuration we find that the shot noise depends on the relative sign of the intrinsic and the extrinsic polarizations.Comment: 4 pages, 3 figure

Bayesian Inference For Exponential Distribution Based On Upper Record Range

This paper deals with Bayesian estimations of scale parameter of the exponential distribution based on upper record range (Rn). This has been done in two steps; point and interval. In the first step the quadratic, squared error and absolute error, loss functions have been considered to obtain Bayesian-point estimations. Also in the next step the shortest Bayes interval (Hight Posterior Density interval) and Bayes interval with equal tails based on upper record range have been found. Therefore, the Homotopy Perturbation Method(HPM) has been applied to obtain the limits of Hight Posterior Density intervals. Moreover, efforts have been made to meet the admissibility conditions for linear estimators based on upper record range of the form mRn+d by obtained Bayesian point estimations. So regarding the consideration of loss functions, the prior distribution between the conjunction family has been chosen to be able to produce the linear estimations from upper record range statistics. Finally, some numerical examples and simulations have been presented

Generalized coherent states for solvable quantum systems with degenerate discrete spectra and their nonclassical properties

In this paper, the generalized coherent state for quantum systems with degenerate spectra is introduced. Then, the nonclassicality features and number-phase entropic uncertainty relation of two particular degenerate quantum systems are studied. Finally, using the Gazeau-Klauder coherent states approach, time evolution of some of the nonclassical properties of the coherent states corresponding to the considered physical systems are discussed.Comment: 17 pages, 10 figures,Physica A: Statistical Mechanics and its Applications, Article in Pres

Taguchi parametric study on the radial and tangential cutting forces in Dry High Speed Machining (DHSM)

In this paper, L8 Taguchi array is applied to find the most important parameters effects on the radial and tangential cutting forces of a Ti–6Al-4V ELI titanium alloy in dry high speed machining (DHSM). The experiments are performed in four cutting speeds of 150, 200, 250, and 300 m/min and two feed rates of 0.03 and 0.06 mm/rev. Also, two cutting tools in types of XOMX090308TR-ME06 of uncoated (H25) and TiAlN+TiN coated (F40M) are used. Results confirm that to minimize the resultant cutting force and radial cutting force, utilizing the lower feed rate and higher cutting speeds were considered as the best levels of factors to reach to its goal

An intelligent capacity management system for interface converter in AC-DC hybrid microgrids

An interface converter (IC) is used in an AC-DC hybrid microgrid (HMG) and its main tasks are frequency regulation in the AC side, adjusting the DC voltage, and controlling the power flow between AC/DC sides based on the droop control method. The IC should be capable of providing ancillary services such as reactive power supply and compensation of unbalanced and harmonic components in the AC side. However, the use of the IC to provide ancillary services occupies its capacity, which may interfere with the main tasks of the IC. In addition, it is shown in this paper that in unbalanced conditions, the effective power capacity of the IC is reduced by considering the current limit of the converter. In this case, the converter may not be able to perform the main task and provide all the necessary ancillary services at the same time, otherwise, it may be exposed to an overcurrent condition. Therefore, an efficient strategy is needed to manage the IC converter capacity to facilitate optimal use of the entire IC capacity even in unbalanced conditions. Given this challenge, this paper proposes an intelligent strategy for managing the IC capacity, which prioritizes the realization of the main task and the provision of ancillary services. The proposed strategy is evaluated, and its effectiveness is proven by simulation results in Matlab/Simulink

Development of outdoor thermal comfort model for tourists in urban historical areas; A case study in Isfahan

The present study intended to evaluate thermal comfort conditions in microclimates of the urban historical areas of Isfahan, Iran during a heatwave. The thermal comfort conditions of different historical sites were compared during the daylight hours to determine the best time to visit each historical site. Using the results of this study, tourists can select the best timeframe with appropriate thermal conditions to visit the historical sites of Isfahan. Along with performing field measurements in the intended historical sites, a questionnaire was used to determine the thermal comfort range of tourists. ENVI-met is used in order to properly simulate the outdoor thermal environment of the historical touristic areas in Isfahan during the hottest as well as the most touristic month of the year. The results of questionnaire and simulations are compared with each other. It was shown that three historical sites with higher thermal stress experience an unpleasant thermal condition. The results of questionnaire show that the comfort range of tourists is within 23.06–29.73 °C PET. The thermal conditions of Si-o-Se Pol, Hasht Behesht and Naqsh-e-Jahan are within the thermal comfort range at 19,20 and 21 p.m. respectively. During the daytime, thermal comfort conditions varied from 4.9 °C PET at 8 a.m. to 8.1 °C PET at 3 p.m. Early morning hours were the most comfortable time to visit the historical sites of Menar-e-Jonban, Masjed-e-Jame and Vank Cathedral in Isfahan. During the peak hours of heat, the priority of thermal comfort goes to Masjed-e-Jame, Menar-e-Jonban and Si-o-Se Pol, respectively