Power and reversal power links for binary regressions: An application for motor insurance policyholders

In binary regression, symmetric links such as logit and probit are usually considered as standard. However, in the presence of unbalancing of ones and zeros, these links can be inappropriate and inflexible to fit the skewness in the response curve and likely to lead to misspecification. This is the case of covering some type of insurance, where it can be observed that the probability of a given binary response variable approaches zero at different rates than it approaches one. Furthermore, when usual links are considered, there is not a skewness parameter associated with the distribution chosen that, regardless of the linear predictor, is easily interpreted. In order to overcome such problems, a proposal for the construction of a set of new skew links is developed in this paper, where some of their properties are discussed. In this context, power links and their reversal versions are presented. A Bayesian inference approach using MCMC is developed for the presented models. The methodology is illustrated considering a sample of motor insurance policyholders selected randomly by gender. Results suggest that the proposed link functions are more appropriate than other alternative link functions commonly used in the literature. Copyright © 2016 John Wiley & Sons, Ltd.     

Hydrogen Peroxide Production of Individual Nanosecond Pulsed Discharges Submerged in Water of Elevated Conductivity

The production of hydrogen peroxide (H₂O₂) is a key parameter for the performance of pulsed discharges submerged in water utilized as advanced oxidation process. So far, any related assessment of the underlying mechanism was conducted for the application of several hundred discharges, which did not allow for a correlation with physical processes. Moreover, the production was rarely investigated depending on water conductivity as one of the most important parameters for the development of submerged discharges. Accordingly, hydrogen peroxide generation was investigated here for individual single discharge events instigated with 100 ns high-voltage pulses in water with three different conductivities and was associated with the discharge development, i. e. spatial expansion and dissipated electrical energy. The approach necessitated the improvement of an electrochemical flow injection analysis based on the reaction of Prussian blue with H₂O₂. Hydrogen peroxide concentrations were quadratically increasing with propagation time and stable for different water conductivities. H₂O₂ production per unit volume of a discharge was constant over time with an estimated rate constant of 3.2 mol ⋅ m⁻¹ s⁻¹, averaged over the crosssectional area of all discharge filaments. However, the individually dissipated energy increased with conductivity, hence, the production efficiency decreased from 6.1 g ⋅ kWh⁻¹ to 1.4 g ⋅ kWh⁻¹, which was explained by increased resistive losses within the bulk liquid.     

水性颜料体系无树脂色浆的制备与应用

中性墨水属于热力学上不稳定的颜料悬浮体系,选择低黏度、高稳定性的色浆是保证墨水体系分散稳定性的重要手段之一。基于此,以颜料炭黑和酞菁蓝为着色剂,配合超分散剂(EK43)与协同增效剂(BM10),制备了两款适用于中性墨水体系的无树脂色浆。首次从色浆粒径与体系分散稳定性角度出发,确定了EK43、BM10用量以及最佳研磨时间,并对其理化性能、稳定性与书写性能进行分析测试。结果表明:在黑色浆中添加质量分数10.0%的EK43、2.5%的BM10,研磨时间为90 min;在蓝色浆中添加质量分数8.0%的EK43、2.0%的BM10,研磨时间为120 min时,两种色浆的粒径与分散稳定性均达到最佳。所制备的无树脂色浆颜料固含量高、黏度较低、储存稳定性好、着色力强,以其调配的中性墨水书写性能良好,且具有较好的离心稳定性和耐热稳定性。     

放射性废物微波处理装置有效输出功率的测定

以微波为热源处理放射性废物的相关技术和装备的研究,在国外已经达到较高水平,在我国的相关研究较少。微波加热即物料在微波场中吸收消耗微波能量,并转化为热能用于物料温度升高。对于物料的处理效果主要与微波的有效输出功率有关。参考Schillman法测定了包括放射性废物微波处理装置的微波炉的有效输出功率,且经验证测定结果准确。微波有效输出功率的确定将对放射性废物微波处理工艺的研究打下基础。     

A new phenomenon of acoustic streaming

This paper describes a new phenomenon of acoustic streaming which takes place when a Helmholtz resonator is excited by an inside sound source with resonant frequency, and takes the form of a strong turbulent jet. The flow visualizations, hot wire and LDV measurements are combined to investigate the process of acoustic streaming. It is found that this kind of acoustic streaming results from the contribution of Reynolds stress.     

Rime- and glaze-ice accretion due to freezing rain falling vertically on a horizontal thermally insulated overhead line conductor

A theory of atmospheric icing due to freezing rain on an overhead line conductor (OHLC) is developed. The rain falls vertically on a horizontal OHLC that is thermally insulated. It is assumed that the collection efficiency of the accretion surface is unity and that this surface is in thermodynamic equilibrium with the environment.

For air temperature T_A 0°C and raindrop temperature T_D 0°C, the freezing rain accretes as rime ice, provided that the temperature of the ice surface T_l < 0°C. The evolution equation governing the mass transfer at the accretion surface is solved analytically, yielding the shape of the rime-ice surface. Equations governing the thermal state of the rime-ice deposit are also given. These determine the onset of wet growth or glaze accretion at the upper stagnation line during suitable environmental conditions.

For environmental conditions producing an ice surface at temperature T_l = 0°gC, the freezing accretes as glaze. Equations governing the heat and mass transfer at the surface determine the shape of the glaze surface and the downward viscous motion of the unfrozen water. For T_D < 0°C, glaze evolution equations are developed for T_A 0°C and T_A 0°C. Analytical solutions of these equations are obtained. In particular, when T_D < −T_A < 0°C, the evolution equation predicts a novel limiting growth that is triangular in shape. Further study of the mass and heat transfer conditions, in the neighborhood of this final stage of glaze accretion, shows that it is maintained in thermodynamic equilibrium with its warm air environment.     

含噪双稳杜芬振子矩方程的分岔与随机共振

研究了含噪声的双稳杜芬振子矩方程的分岔与随机共振的关系，并根据它们的关系, 从另 一个角度揭示了随机共振发生的机制. 首先在It?方程的基础上，导出了双稳杜芬振子在白噪声和弱周期信号作用下的矩方程，其次以噪声强度 为分岔参数分析了矩方程的分岔特性，再次分析了矩方程的分岔与双稳杜芬振子随机共振 之间的关系，最后根据该对应关系从另一种观点提出了双稳杜芬振子随机共振的机制，该 机制是由于以噪声强度为分岔参数的矩方程发生了分岔，而分岔使得原系统响应均值的能量分布发生了转移，使能 量向频率等于输入信号频率的分量处集中，使得弱信号得到了放大，随机共振发生了.     

Experimental study and direct numerical simulation of the evolution of disturbances in a viscous shock layer on a flat plate

The evolution of disturbances in a hypersonic viscous shock layer on a flat plate excited by slow-mode acoustic waves is considered numerically and experimentally. The parameters measured in the experiments performed with a free-stream Mach number M _∞ = 21 and Reynolds number Re _L = 1.44 · 10⁵ are the transverse profiles of the mean density and Mach number, the spectra of density fluctuations, and growth rates of natural disturbances. Direct numerical simulation of propagation of disturbances is performed by solving the Navier-Stokes equations with a high-order shock-capturing scheme. The numerical and experimental data characterizing the mean flow field, intensity of density fluctuations, and their growth rates are found to be in good agreement. Possible mechanisms of disturbance generation and evolution in the shock layer at hypersonic velocities are discussed. __________ Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 47, No. 5, pp. 3–15, September–October, 2006.     

An Overview on Non-Ideal Vibrations

We analyze the dynamical coupling between energy sources and structural response that must not be ignored in real engineering problems, since real motors have limited output power.