Modularized design for cooperative control and plug-and-play operation of networked heterogeneous systems

In this paper, a cooperative control analysis and design method is investigated for heterogeneous dynamical systems that may be of arbitrary relative degree or nonminimum-phase or both. To achieve consensus or cooperative stability, a negative value of input-feedforward passivity index is used to accommodate and analyze such systems, and the magnitude of the index value is also used as the impact coefficient to quantify the impacts of heterogeneous dynamics of these systems on their networked operations. Physical-system-level designs are explicitly carried out to make individual linear and nonlinear systems (which are either feedback linearizable or nonminimum phase of certain form) become passivity-short and to embed one pure integrator into their input–output dynamics. The network-level distributed control can simply be chosen without any knowledge of the heterogeneous dynamics but with only information of an upper bound on their impact coefficients. It is shown, using the impact equivalence principle, that these controls separately designed but implemented together always ensure either local or global consensus and that a global non-trivial consensus emerges if and only if the information network has at least one globally reachable node or is varying but cumulatively connected. The proposed methodology of fully modularized designs unravels complexity of analyzing and designing cyber–physical systems and enables their plug-and-play into networked operations.     

A multi-echelon production–inventory system with supply disruption

The article investigates an integrated multi-layer supply chain model consisting of supplier, manufacturer and retailer while supply disruption, machine breakdown, safety stock, maintenance breakdown occur simultaneously. At beginning of the production, manufacturer keeps some raw materials in stock received from second supplier at high price, as safety stock due to supply disruption of first supplier. Corrective maintenance is done immediately to restore its normal stage when machine breakdown occurs. Stock out situations at manufacturer and retailer are considered due to disruption of production for machine breakdown. The integrated expected costs of the chain in centralized (collaborating) and decentralized (Stakelberg approach) system are compared. A numerical example and its sensitivity analysis are provided to test feasibility of the model.     

汾河临汾城区段蓄水美化工程建设特点及工程措施

汾河临汾城区段蓄水美化工程位于汾河下游，针对发生中小洪水机率高、河道水质差、水源缺乏、河床易冲刷且渗漏严重等特点，采取了分槽泄洪、排污、桩柱抗冲、高喷防渗、多种水源补水等措施。     

Water technologies and the environment: Ramping up by scaling down

The world is facing a global water crisis. Already, deficiencies in water supply and water quality are causing widespread human suffering. About 1.1 billion people lack access to clean water, and 2.6 billion do not have access to improved sanitation facilities. Everyday, 4500 children throughout the world die from preventable diseases caused by the lack of clean water and sanitation. China, India, and the United States are all facing major shortages of freshwater, and water pollution is having serious impacts on public health and the environment in both China and India. Major investments in science and technology will be required to address the water issues of the future. A new generation of innovative, small-scale technologies is needed to prevent and control pollution, and to restore watersheds. Creative, collaborative approaches to addressing the world's decline in freshwater resources are urgently needed.     

破解铸造企业用工荒的一些思考与措施

面对现阶段愈演愈烈的用工荒,从宏观与微观两方面分析了用工荒产生的成因、特点、分布,利用人力资源管理理论,阐述了一些企业用工方面存在的典型问题以及用工误区,提出了一些建设性的意见与措施。     

Understanding the importance and timing of panic buying among U.S. Households during the COVID-19 pandemic

The surge in panic buying during the novel Coronavirus (COVID-19) pandemic led to a temporary shortage of several staples and basic supplies in grocery stores, thus limiting the public’s access to basic needs and exacerbating stress and anxiety. The negative societal consequences of panic buying highlight the importance of understanding and planning for such behavior. This study investigates the main factors that correlate with the perceived importance and timing of panic buying decisions in the US. In doing so, we provide a breakdown of the importance of panic buying across a list of common food and non-food grocery items and show a considerable variation based on product type. We also uncover heterogeneities in the importance and timing of panic buying based on demographic and behavioral characteristics, including residence area, household size, presence of children and elderly in the household, household income, ethnicity, and specific views about COVID-19. Finally, we analyze correlations between the importance of panic buying and various motivations that are believed to underlie this behavior. Results show that the perceived importance of panic buying is most heavily associated with the need for control, belief that it is the smart thing to do, and urge to minimize number of trips to grocery stores.     

洁净耐用型钛制换热器特殊工艺研究与实践

结合近年现场施工实践，分析研究了化工医药用换热器(材质为工业纯钛)的结构特点、制造缺陷与产生原因，以及在制造中几个关键环节应采取的主要工艺及优化措施。     

我国旧工业建筑再利用初探

该文分析了我国旧工业建筑再利用制度和实践的发展历程,通过对我国工业建筑再利用实例的解读,分析并提出了国内旧工业建筑再利用的现状和不足.     

浅谈建筑节能

随着全球资源的日益短缺,提倡发展可持续建筑,对耗能建筑需采取节能措施,使建筑成为节能建筑。     

国内聚丙烯市场现状及其发展方向

聚丙烯5年内国内总产能翻了一番,但生产装置数量众多,单套装置生产能力偏小、技术水平较低。未来聚丙烯发展,应着眼于淘汰落后产能,提高行业整体盈利能力;调整产品结构,提高行业总体技术含量;加快新技术开发,增强自主创新能力;提高服务意识,完善市场技术服务体系。