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Raphael Muzondiwa Jingura Reckson Kamusoko 《Energy Sources, Part B: Economics, Planning, and Policy》2018,13(4):224-230
Jatropha curcas L. has emerged in recent times as a leading energy crop in sub-Saharan Africa with over 32 countries in the region involved in its cultivation. By 2008, five countries in the region (Senegal, Nigeria, Mali, Ethiopia, and Zimbabwe) had policies promoting Jatropha cultivation. These policies were not informed by empirical evidence arising from the performance of Jatropha in the region. This paper analyses performance data of Jatropha in the region with a view to synthesizing information that is useful for evidence-based policy formulation. Production data in terms of agronomic issues and seed yields are analyzed. The results show that most of the attributes generically associated with Jatropha have not been achieved in the region and there has been inadequate research to support Jatropha cultivation. Policies supporting cultivation of Jatropha need to be informed by these observations in order to promote viable cultivation of the crop. 相似文献
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Lean practices are known to increase operational performance. Previous research has identified critical success factors for implementing lean practices. This research aims to examine the extent to which success factors are critical for various degrees of lean practice implementation. Using multiple-respondent self-assessments from 33 Dutch manufacturing small and medium-sized enterprises (SMEs), we conducted a Necessary Condition Analysis. Our findings indicated that the criticality of success factors is progression dependent. In the initial stages of the lean journey, SMEs could improve their lean practices in a bottom-up manner through local factors such as a learning focus, improvement training and support congruence. When lean practices are more advanced, some company-wide factors must be present: top management support, a shared improvement vision and a supplier link. Our findings question the universality of success factors such as strategic involvement and indicate the need for a more dynamic model of lean implementation. 相似文献
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在工程建设标准的制定和修订过程中,如何科学地确定编制顺序一直是困扰标准管理部门的难题,采用传统方式“按需制标”,具有盲目性、主观性,容易造成标准在制定和修订过程中的互相重复、滞后与矛盾。为了保证标准制定和修订工作的协调性,指导标准体系中各标准的制修订顺序,引入复杂网络拓扑结构,将同一标准类型下的标准构成功能团,根据相互之间的关系形成复杂网络,采用剥落算法对其网络节点重要性排序,进而确定标准制修订的优先度。通过对建筑给水排水工程规范标准修订的实证分析,总结工程建设标准的网络拓扑优先度评价的算法模型,实现制定和修订顺序的自动计算,从而更加科学地指导标准的制定和修订工作 相似文献
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建立了考虑水位骤降条件下的下伏隧道堤防模型,依托湘江某下伏隧道堤防工程,基于堤防边坡渗流原理,结合有限元应力计算,探讨了不同水位骤降速率下的浸润线情况,计算了堤防安全系数。研究结果表明:湘江水位骤降速率越快,浸润线变化范围越大,浸润线变化范围与水位降落速率成正比;湘江水位骤降速度在3 m/d^4 m/d,水位降到28.8 m时,堤岸失去稳定;水位骤降并非整个过程中堤岸均处于失稳状态,而是水位降至某高度后堤岸失稳,骤降速率增快对堤防安全系数有一定负面作用。研究结果对隧道下穿堤防建设具有一定指导意义。 相似文献
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Outcome‐based ventilation: A framework for assessing performance,health, and energy impacts to inform office building ventilation decisions 下载免费PDF全文
This article presents an outcome‐based ventilation (OBV) framework, which combines competing ventilation impacts into a monetized loss function ($/occ/h) used to inform ventilation rate decisions. The OBV framework, developed for U.S. offices, considers six outcomes of increasing ventilation: profitable outcomes realized from improvements in occupant work performance and sick leave absenteeism; health outcomes from occupant exposure to outdoor fine particles and ozone; and energy outcomes from electricity and natural gas usage. We used the literature to set low, medium, and high reference values for OBV loss function parameters, and evaluated the framework and outcome‐based ventilation rates using a simulated U.S. office stock dataset and a case study in New York City. With parameters for all outcomes set at medium values derived from literature‐based central estimates, higher ventilation rates’ profitable benefits dominated negative health and energy impacts, and the OBV framework suggested ventilation should be ≥45 L/s/occ, much higher than the baseline ~8.5 L/s/occ rate prescribed by ASHRAE 62.1. Only when combining very low parameter estimates for profitable impacts with very high ones for health and energy impacts were all outcomes on the same order. Even then, however, outcome‐based ventilation rates were often twice the baseline rate or more. 相似文献
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