无烟煤制工业燃气项目原料煤价与经济性的关系分析

针对我国建材行业传统使用的常压固定床煤气发生炉及化肥行业固定床间歇气化炉面临淘汰,无烟煤市场萎缩的情况,提出以晋城无烟煤为原料,利用赛鼎碎煤加压气化技术,生产适合建材行业大规模使用的工业燃气。以无烟煤为原料的河北沙河年产26亿m^3工业清洁燃气项目为基础,对无烟煤与天然气价格、项目经济性的关系进行了分析,结果表明,以晋城无烟块煤运到河北沙河的到厂价935元/t计算,盈亏平衡天然气价约2.26元/m^3;以沙河工业天然气到户售价2.5元/m^3计算,盈亏平衡到厂煤价约1 077元/t,项目经济性较好。     

热轧双相钢生产现状、存在问题及发展趋势浅析

介绍了国内外热轧双相钢的发展现状；对热轧双相钢的成分体系和关键生产工艺进行了总结，指出了目前热轧双相钢在生产过程中存在的问题；提出了未来热轧双相钢的主要发展方向为低成本、高强度、低负荷、高表面质量和“以热代冷”。     

九仗沟金矿上向进路采场结构参数优化

针对九仗沟金矿采场结构参数合理性差、采矿成本偏高等问题,采用FLAC~(3D)数值模拟对采场结构参数进行优化研究,得到较优的采场跨度。在九仗沟金矿进行现场工业性试验,并在试验采场开展经济效益统计和计算工作,得到试验采场的经济效益。数值模拟结果说明九丈沟金矿上向进路采场的极限跨度为8.0m,采场破坏程度较轻。现场工业试验结果说明7.0m作为采场跨度具有较好的经济效益,保证安全生产的同时提高采矿效率。     

两个大型住宅项目设计配套消防备供电源供电方案分析及优劣对比

通过对两个大型住宅项目配置消防备供电源供电方案进行对比,分析由此产生的建设安装造价成本高低,以及后期物业管理程序的难易程度,总结出适宜于大型住宅项目的消防备供电源供电方案,既能降低建设投资成本,又可以简化后期物业管理程序,更好地保障消防系统供电安全,值得推广。     

Time-frequency domain causality of prime building cost and macroeconomic indicators in Ghana: implications for project selection

According to the Ghana Statistical Service, construction activity generated US$3.8 billion in 2014, representing about 12.7% of nominal GDP. A key factor that most investors in the construction sector consider in project selection is cost which has escalated over the years. Therefore, we examine the co-movements and causality in the time and frequency domains between the prime building cost index (PBCI) and its disaggregates on one hand and inflation and exchange rate on the other hand in Ghana. The findings revealed that the degree of co-movement between PBCI and inflation was significant at the 5% level and occurred over the long-run, indicating that construction cost drives inflation. The degree of co-movement between the prime build cost index and exchange rate occurred within the short term. These co-movements have policy implications for substituting inflation and exchange rates in project costing by investors in Ghana. The co-movement between the PBCI and inflation in the medium to higher frequencies suggests that inflation risk-averse investors should consider short-term projects. Again, the short to medium frequency co-movements between the PBCI and exchange rate indicates that investors should consider exchange rate risk in long-term projects.     

Optimal cost design of flow lines with reconfigurable machines for batch production

Modular reconfigurable machines offer the possibility to efficiently produce a family of different parts. This paper formalises a cost optimisation problem for flow lines equipped with reconfigurable machines which carry turrets, machining modules and single spindles. The proposed models take into account constraints related to: (i) design of machining modules, turrets, and machines, (ii) part locations, and (iii) precedence relations among operations. The goal is to minimise equipment cost while reaching a given output and satisfying all the constraints. A mixed integer programming model is developed for the considered optimisation problem. The approach is validated through an industrial case study and extensive numerical experiments.     

带缓冲区且产品保修的设备预防性维护建模

论文考虑的是一个完美的生产系统,即生产系统所生产的产品均没有质量问题。为提高设备的可靠性,调整市场需求,提出带缓冲区的设备预防性维护优化建模方法。已经出售的产品,顾客在使用过程中可能会出现故障,基于这个情况,在保修期内会予以免费维修。找出生产系统的运行时间(T)和缓冲区库存量(S),以此为决策变量建立期望成本模型。在此基础上,构造求解最优策略的算法。通过数值算例演示了该模型,通过灵敏度分析确定了最优策略和相关参数的关系。     

An e-government framework for assessing readiness for public sector e-procurement in a lower-middle income country

ABSTRACT

Governments globally are leveraging information and communication technology (ICT) growth towards improving the quality of public procurement services for socio-economic development. However, the extent of its application differs across nations. Notwithstanding the extant theoretical and empirical literature on IT for development, knowledge on how to assess readiness for adopting a full e-procurement system in the public sector of lower and lower-middle income countries (LMICs) begs for understanding. With the narrative of Ghana, we address this gap by drawing on the institutional and economic theory and the United Nations E-Government Development Index towards a holistic framework beyond the dyad of linear website functionalities and internet focus of prior e-government adoption models. Elite interviews gathered from multiple cases from Ghana’s public sector reveals the key readiness determinants for a full public sector e-procurement system. This study has significant implications for shaping the process-oriented management of government e-procurement projects towards socio-economic development in LMICs amid their complex institutional and socio-technical environments.     

2020年国内外宏观经济形势分析及预判

2020年,预计全球贸易进展局势出现缓和,世界经济增长小幅回升至2.6%左右,主要经济体面临的贸易政策、货币政策和地缘政治局势等不确定性因素仍较多,世界经济增长面临的下行风险仍较大。2019年中国经济总体平稳,GDP增长6.1%。2020年我国经济将继续保持增长稳健、结构优化、动能转换的发展态势,预计将实现6.0%的增长。