Life style and home environment are associated with racial disparities of asthma and allergy in Northeast Texas children

A high prevalence and racial disparities in asthma and allergy have been observed in American children. This study aimed to identify risk factors for asthma and allergy among children, and their contribution to racial disparities in allergy prevalence. A population-based cross-sectional study was carried out among children aged 1-8 years in Northeast Texas 2008-2009. The health conditions, life style and home environment of 3766 children were surveyed by parental questionnaires through e.g. daycares, elementary school, and medical clinics. Among participants who indicated their ethnicity, 255 were Mexican-Americans, 178 Afro-Americans and 969 Caucasians. Afro-American children had a significantly higher prevalence of asthma and eczema. Caucasian had the highest prevalence of rhinitis. Compared to Mexican-American children, Afro-American and Caucasian children were breast fed shorter time, more often went to day care center, had pets and environmental tobacco smoke exposure at home more often. For all children, being at a day care center, being exposed to dampness and environmental tobacco smoke at home were strong risk factors for asthma and allergy. Central air conditioning system was associated with an increased prevalence of wheeze among Mexican-American children, while pets were associated with an increased risk of rhinitis among Afro-American and Caucasian children. Caucasian children were generally not healthier than relatively poor Mexican-American children. Differences in the prevalence of asthma and allergy between races cannot be explained by socioeconomic status only. Life style and home environmental exposures are important risk factors for asthma and allergy in Northeast Texas children.     

钻孔灌注桩孔壁稳定性分析

 采用有限元数值模拟与有限元强度折减法,研究土体性质、泥浆相对密度、孔深、孔半径等因素对钻孔灌注桩孔壁稳定性的影响。研究结果表明：(1) 黏性土地基中孔壁稳定性问题主要是缩径问题,土质越差、孔半径越大或孔越深,缩径量越大,提高泥浆相对密度能有效地减小缩径量;(2) 砂土地基中孔壁稳定性问题主要是坍孔问题,孔壁土体产生一定的塑性区后,很容易发生破坏,同时这种破坏会向四周蔓延扩散,最终形成坍孔。影响砂土地基孔壁稳定性的主要因素是泥浆相对密度,为保证孔壁稳定,砂土地基中最小泥浆相对密度应使得泥浆侧压力不小于土体静止侧压力。研究成果可为软土地基中钻孔灌注桩设计与施工提供参考。     

长春国际汽车公园布局分析

通过对长春国际汽车公园总体布局和各个主要区域布局的分析,阐释了长春国际汽车公园汽车文化这个主题。分析了长春国际汽车公园布局的一些特点以及存在的不足。     

城市边缘区的城市设计策略研究——以莱芜市钢城区永兴路为例

通过对莱芜市钢城边缘区永兴路的空间解读,提出了构建整体性城市设计的目标,重点通过对带形区域的功能定位、城市空间形态重新进行评估和认识,对土地资源进行整合,研究确定城市边缘区城市设计的策略。     

基于吉布斯采样与压缩感知的二维非平稳CPT数据快速插值方法

静力触探试验(Cone Penetration Test,CPT)常被用于确定地下土体分层情况及层内土体的力学参数等。由于工期、工程投入、技术等条件限制,沿水平方向的CPT钻孔数目通常非常有限,有必要利用空间插值或随机模拟来估计未采样位置的CPT试验数据。提出一种有效的蒙特卡洛方法,可直接根据有限的CPT试验钻孔数据估计未采样位置的CPT数据,该方法将二维贝叶斯压缩感知框架与吉布斯采样相结合,并引入克罗内克积以提高其计算效率,然后用一系列数值及实际工程案例验证了所提方法的可靠性。结果表明:该插值方法合理,不仅能如实反映数据本身的非平稳特点,且采用序列更新技术后可显著降低时间成本,具有更强的适应能力。此外,插值结果的准确性、可靠性与已有CPT钻孔的距离成反比、与已有钻孔的数目成正比,反映出方法本身数据驱动的特点。     

Device and circuit simulation of printed polymer electronics

For the electrical simulation of all printed polymer circuits an AIM-SPICE model was developed, which is based on an a-silicon approach. By fitting the parameters to the behaviour of our polymer devices, we obtain a model, which allows to model all-printed polymer transistors and circuits.     

Ultrasonic vibration-assisted pelleting for cellulosic biofuel manufacturing: Investigation on power consumption

Cellulosic ethanol produced from cellulosic biomass is an alternative to petroleum-based transportation fuels. Raw cellulosic biomass has low density, causing high costs in their storage, transportation, and handling. Ultrasonic vibration-assisted (UV-A) pelleting can increase the density of cellulosic biomass. Effects of UV-A pelleting variables on pellet quality (density, durability, stability, and strength) and sugar yield have been reported. However, power consumption in UV-A pelleting has not been fully investigated. This paper presents an experimental investigation on power consumption in UV-A pelleting of wheat straw. Effects of input variables (biomass moisture content, biomass particle size, pelleting pressure, and ultrasonic power) on power consumption are investigated. Results show that power consumption in UV-A pelleting increases as moisture content and particle size decrease, and as pelleting pressure and ultrasonic power increase.     

A four-point-bending-test for the stability assessment of glass frit bonded molded microsensors

For increasingly miniaturized micromechanical sensors the silicon package is thinned and therefore more sensitive to thermomechanical stresses caused by the production stages. We present a four-point-bending-test that enables the investigation of reliability relevant loading like warping. The initiation of crack growth at the glass frit bonding frame is observed by an infrared camera and critical fracture mechanical parameters are determined for different tensile and shear mode contributions. Based on this crucial fracture mechanical data the stability of silicon packages can be assessed.     

How much wind energy will be curtailed on the 2020 Irish power system?

This paper describes a model of the 2020 Irish electricity system which was developed and solved in a mixed integer programming, unit commitment and economic dispatch tool called PLEXOS^®. The model includes all generators on the island of Ireland, a simplified representation of the neighbouring British system including proposed wind capacity and interconnectors between the two systems. The level of wind curtailment is determined under varying levels of three influencing factors. The first factor is the amount of offshore wind, the second is the allowed limit of system non-synchronous penetration (SNSP) and the third is inclusion or exclusion of transmission constraints. A binding constraint, resulting from the 2020 EU renewable energy targets, is that 37% of generation comes from wind. When the SNSP limit was increased from 60% to 75% there was a reduction in wind curtailment from 14% to 7%, with a further reduction when the proportion of wind capacity installed offshore was increased. Wind curtailment in the range of SNSP limit of 70–100% is influenced primarily by the inclusion of transmission constraints. Large changes in the dispatch of conventional generators were also evident due to the imposition of SNSP limits and transmission constraints.     

Nonlinear analysis of the backdraft phenomenon in room fires

The backdraft phenomenon in room fires is a typical example of nonlinear behavior. In this paper, a simplified mathematical model of the backdraft phenomenon is established based on energy balance equation and the dimensionless model equations are presented using concepts of nonlinear dynamical system theory, the nonlinear dynamical mechanism is analyzed, and the relationship between system control variables and fire conditions is studied.