京沪高铁制冷工况车内环境测试结果分析

测试了京沪高铁制冷工况运行过程中,车厢内温湿度分布、送风温度、风速分布,分析了其是否满足人体舒适性要求。记录京沪高铁车厢外环境温湿度值,分析了其对车厢内环境参数的影响。并通过计算PMV数值,分析了车内乘客热舒适性程度。     

高速列车客室内部流场计算流体动力学数值模拟

针对高速列车的车厢内温度场和流场进行CFD模拟分析,对车内热舒适性做出评价。本文计算得出列车车厢在4500m3/h的送风量和18℃的送风温度下,车厢内的平均温度约为24.9℃,PMV值介于0~1.0,车厢内的热环境为中等舒适状态。车厢内的空气龄较小,乘客区气流分布较为合理。部分区域,如行李架和车厢后部,存在温度偏高和空气龄较大的现象。     

空调客车车内计算参数的优化与节能

本文根据PMV—PPD指标，分析了K25型软卧客车的车内空调计算参数——空气温度和湿度对热舒适性的影响，并通过计算软卧客车的负荷和制冷量分析了温、湿度对空调能耗的影响。最后指出：优化车厢内空调计算参数，对铁路客车空调的节能有重要的意义。     

地铁车厢条缝送风方式数值模拟

目前我国地铁列车内的人体热舒适性及空气质量难以达到要求。本文采用κ-ε湍流模型,对不同尺寸的条缝风口送风方式下的地铁车厢的三维空气流场和温度场进行数值模拟,综合分析车厢内温度、空气流速、粒子示踪、空气龄、CO2含量、PPD以及PMV等指标,说明各工况的空调效果及人体热舒适性,为改善地铁车厢空调制冷情况提供理论依据。     

某型急救车车厢内卧姿伤病员热舒适性分析与评价

文章以某型急救车空调车厢为例,运用热舒适性评价指标PMV（predictedmeanvote）研究了夏季车厢内卧姿伤病员的热舒适性状况。根据GJB898A-2004的方法测量不同位置（头部、腹部、腿部）的环境变量,对各变量进行加权处理,并参照GB／T18049-2000确定人体代谢率和服装热阻,编写Matlab迭代程序求解服装表面温度,最后计算出PMV指标值。由计算结果分析了卧姿伤病员的热舒适性随时间和空间的变化规律及影响伤病员热舒适性的主要因素,提出了改进伤病员热舒适性的措施。     

影响空调列车车厢内热舒适性的因素分析

分析了空气温、湿度变化对PMV值的影响,为采用基于PMV指标的热舒适性控制以改善车厢内热环境的舒适性提供了参考。     

不同气流组织下空调客房热舒适性的数值模拟

基于不同的气流组织利用CFD技术对空调客房室内的速度场、温度场、PMV、PPD值进行数值模拟,通过对3种气流组织速度场、温度场比较,结果显示散流器送风能够得到均匀的温度场、速度场。同时,PMV、PPD值更靠近推荐值范围,热舒适性更好,从而为改善空调客房的热舒适性设计提供了方法和理论依据。     

医院空调节能运行方案及其舒适性研究

采用K-ε湍流模型对病房内三维紊流流动和传热进行了数值模拟，计算得到单元式集中空调系统与全热换热器在三种不同运行模式下室内热舒适性指标PMV及PPD的分布情况。通过比较不同运行模式下人体活动区域内的热舒适性指标分布情况，确定空调系统与全热换热器的节能运行方案。     

某办公室热环境CFD模拟研究

采用Airpak软件对某办公室夏季空调环境进行了数值模拟,通过对办公室截面速度场、温度场、空气龄,以及PPD、PMV的分析研究,对办公室的热环境进行了评价。为相关系统的设计提供了参考。     

火车站候车厅热舒适性模拟研究

本文利用CFD技术作为辅助工具,运用商用软件Airpak,采用k-ε模型进行求解,对西安北站候车大厅的热舒适性进行模拟计算,通过模拟计算对热舒适性进行预测。计算结果表明PMV以及PPD值均能满足规范要求。通过模拟计算可以利用较低的成本为工程设计提供可靠的理论依据。     

Subsidiary Initiatives in the Institutional Environment

We study subsidiaries of a MNC and research why they implement initiatives that deviate from organizational values of headquarters. Initially we relied only on the concept of institutional duality and expected that pressures in the institutional environment and values of headquarters explain the agency of the subsidiaries. But the results of our extensive participatory observation showed that the organizational values of subsidiaries (rather than those of headquarters) helped explain the subsidiaries’ actions. In conclusion, we find that there are limits to the predictive power of the concept of institutional duality. Our study shows that a distinction between values of headquarters and values of subsidiaries is necessary in order to understand the agency of subsidiaries. We suggest a concept of ‘institutional trinity’ that distinguishes between these two values as well as pressures in the institutional environment. Our research demonstrates that an MNC can benefit from a subsidiary that develops its own organizational values. If headquarters is subsequently ready to adopt some of these subsidiary values, it may be able to adapt more easily to a changing institutional environment.     

粘弹性支座RC梁在低速冲击下的动力响应计算

给出了基于Hertz接触理论的冲击体与梁结构之间的局部接触力-接触变形关系。根据弯曲理论,建立了具有粘弹性支座钢筋混凝土梁在低速冲击作用下的弹塑性动力响应计算方法,并通过算例分析了冲击速度、支座刚度和支座阻尼对动力响应的影响。分析发现:梁的总位移随冲击速度增大而增大,当冲击速度足够大时梁将出现塑性变形。支座条件对梁的动力响应有较大影响,梁的总位移最大值随支座刚度增大而减小,而相对位移最大值随支座刚度增大而增大,振动频率随支座刚度增大而明显增大;梁的总位移最大值随支座阻尼增大而减小,相对位移最大值随支座阻尼变化不明显,位移幅值衰减值随支座阻尼增大而增大,但振动频率不受支座阻尼影响。结果表明:采用粘弹性支座既能减小钢筋混凝土梁的相对位移幅值,又能加速梁的位移幅值衰减,提高了梁结构的抗冲击能力。     

冲击载荷下包装物随机响应的数字特征

据跌落高度变化样本值,用最大似然法求得冲击加速度峰值的概率密度函数,据此得出该随机变量加速度峰值的数字特征。假设包装件为单自由度结构系统,由其加速度激励的频率响应函教而求出包装物响应加速度峰值的数字特征,以此作为缓冲包装设计的依据。     

Are our values becoming more fit for artificial intelligence society? A longitudinal study of occupational values and occupational susceptibility to technological substitution

Advanced technologies are changing our working life in unpredictable ways. Consequently, a fear of technologically induced mass unemployment has re-emerged. The increased precarity associated with the technological substitution of work could lead to a regression towards materialist values that are more accepting of authoritarianism and xenophobia. Crucially, these values are less associated with the skills demanded in future work, which tends to be depicted as demanding higher levels of innovation, creative and social skills that are associated with post-materialist values. Current research has thus far overlooked the cultural aspects of large-scale technological substitution of work, which this study illuminates. We investigate how the relationship between occupational values and occupational automatability has developed between 2002 and 2018 in Europe. The results demonstrate that occupational values have been rather stable throughout the period. Occupational values are not becoming more or less fit for artificial intelligence society as would be expected if the context becomes increasingly precarious or innovation-driven. The paper demonstrates that a cultural adaptation to this type of society has not yet occurred.     

Experimental exploration of discrepancies in F-number correlation of flammability limits

Flammability limits measurement has been made by ASHRAE method for some 20 kinds of combustible gases and vapors. These compounds have been selected mainly because the literature values of flammability limits are not consistent with the F-number calculated ones [J. Hazard. Mater. A 82 (2001) 113]. As a result, it has been found that the newly obtained values of flammable range are classified into three groups. For the first group of compounds, the present values agree well to the literature values. For the second group, the present values do not agree to the literature values but agree with the calculated ones. For the third group ones, the present values neither agree to the literature values nor to the calculated ones. There are 4, 13, and 6 compounds in the respective groups.     

Shared Consumer Needs Across India and China: A Path to Global Advertising of Services?

Global advertising often uses cultural values to standardize globally advertised messages. However, this exploratory study investigates the possibility that rather than cultural values (and consumer wants), it is consumer needs that are strongly shared across countries. Therefore, it might be possible to replace cultural values with these shared consumer needs for the standardization of globally advertised messages. This study does not argue against the universality of the content or structure of values, but rather against the universality of the importance of values across countries. The means-end theory is used to link the relationships between consumer wants, needs, and values. Data collected from Indian and Chinese consumers of information technology education services were analyzed using the laddering technique to reveal hierarchical value maps for each of the two country samples. The results indicate that at the level of consumer wants, Indian consumers seek more tangible attributes while Chinese consumers seek more intangible ones. Also, at the level of cultural values, Chinese consumers associate more values with the service than their Indian counterparts. At the same time, within both groups of consumers the same set of consumer needs were strongly shared among consumers; these were the need for knowledge enhancement, the need for skill improvement, and the need for better employability. Therefore, the results suggest that if managers want to successfully standardize their global advertising, their message strategy could focus on consumer needs that are strongly shared across countries.     

Theoretical stress concentration factors for short flat bars with opposite U-shaped notches subjected to in-plane bending

The values of existing theoretical stress concentration factors for rectangular uniform thickness plates, with opposite U-shaped notches, subjected to in-plane bending do not include the effect of length as a significant parameter. This work demonstrates that below a threshold value, defined as transition length, these stress concentration factors cease to be valid and, notably, also demonstrates that below this threshold the magnitude of the stated factors may be significantly larger than existing values; a fact that may have important consequences for the accurate estimates of fatigue life. The finite element determined, theoretical stress concentration factors for the stated geometry and loading, including length as a parameter, for the existing range of the notch radii values, as well as an extended range of these values are reported and are presented in the standard graphical form. The corresponding values of the transition lengths were computed and are reported as well.     

An Introduction to Mathematical Statistics,Second Edition

A procedure of studentizing or standardizing the residuals by dividing them by their estimated standard deviations is proposed for testing for outliers in simple linear regression. A simulation study yielded the critical values of the test statistic, and it is shown that these values are extremely close to the values in Grubbs' (1950) Table IA and independent of the values taken for the independent variable.     

Dear Citizen Photojournalists: Who are you? Studying the motivations and values of citizen photojournalists

The photojournalistic landscape is undergoing dramatic change, and professional photojournalism is increasingly being supplemented with – and in some cases, replaced with – amateur, citizen photojournalistic content. This study undertakes to examine these changes in the visual change in the news environment by looking at the motivations and values of citizen photojournalist through interviews with 19 citizen photojournalists. The findings suggest that citizen photojournalists are savvy to the values and photojournalism, but often reject these normative values in lieu of values that reflect the characteristics of amateur content-creators.     

Electric equivalent circuit for flexural vibrations in piezoelectric materials

General expressions for the values of the components of an electric equivalent circuit are derived for flexural vibrations. These expressions are applied to some interesting electrode configurations. The obtained values are in good agreement with experimental values and values specified by manufacturers of watch crystals. It is noted that solving Laplace's equation for the dielectric field is sufficient in order to obtain the values of the vibration amplitude, the piezoelectric current, and the equivalent components. The piezoelectric part of the electric field need only be considered if very accurate values of the resonance frequencies are desired. It is shown how accurate estimates can be obtained without the need of advanced calculation tools.