制订企业规章制度应注意的主要问题

分析了当前制订企业规章制度面临的难题,提出了应注意的三个主要问题：一是要注意把握好规章制度的有效性、实用性、强制性以及详略问题,尽量降低法律风险;二是要注意把握好规章制度的名称、结构、制订程序,尽量增强规范性,并应注意在充分汲取执行者意见的基础上再出台有关规章制度,以增强可操作性;三是尽量做到协调统一和及时更新,以防止“文件打架”。还对企业规章制度的评价问题进行了探讨。     

公路水毁处治方案

今年辽宁省受台风等极端天气影响,有些公路局部路段出现较严重的水毁现象。就水毁路段的现状、处治方案及今后设计、施工中应注意的问题进行论述。     

Assessing the impact of tactical airport surface operations on airline schedule block time setting

With the growth of air traffic, airport surfaces are congested and air traffic operations are disrupted by the formation of bottlenecks on the surface. Hence, improving the efficiency and predictability of airport surface operations is not only a key goal of NASA’s initiatives in Integrated Arrival/Departure/Surface (IADS) operations, but also has been recognized as a critical aspect of the FAA NextGEN implementation plan. While a number of tactical initiatives have been shown to be effective in improving airport surface operations from a service provider’s perspective, their impacts on airlines’ scheduled block time (SBT) setting, which has been found to have direct impact on airlines’ on-time performance and operating cost, have received little attention. In this paper, we assess this impact using an econometric model of airline SBT combined with a before/after analysis of the implementation of surface congestion management (SCM) at John F. Kennedy International Airport (JFK) in 2010. Since airlines do not consider gate delay in setting SBT, we find that reduction in taxi-out time variability resulting from SCM leads to more predictable taxi-out times and thus decreases in SBT. The JFK SCM implementation is used as a case study to validate model prediction performance. The observed SBT decrease between 2009 and 2011 at JFK is 4.8 min and our model predicts a 4.2 min decrease. In addition, Charlotte Douglas International Airport (CLT) is used as an example to demonstrate how different surface operations improvements scenarios can be evaluated in terms of SBT reduction.     

Lightweighting shipping containers: Life cycle impacts on multimodal freight transportation

Freight transportation by truck, train, and ship accounts for 5% of the United States’ annual energy consumption (U.S. Energy Information Administration, 2017a). Much of this freight is transported in shipping containers. Lightweighting containers is an unexplored strategy to decrease energy and GHG emissions. We evaluate life cycle fuel savings and environmental performance of lightweighting scenarios applied to a forty-foot (12.2 meters) container transported by ship, train, and truck. Use phase burdens for both conventional and lightweighted containers (steel reduction, substitution with aluminum, or substitution with high tensile steel) were compared to life cycle burdens. The study scope ranged from the transportation of one container 100 km to the lifetime movement of the global container fleet on ships. Case studies demonstrated the impact of lightweighting on typical multimodal freight deliveries to the United States. GREET 1 and 2 (Argonne National Laboratory, 2016a,b) were used to estimate the total fuel cycle burdens associated with use phase fuel consumption. Fuel consumption was determined using modal Fuel Reduction Values (FRV), which relate mass reduction to fuel reduction. A lifetime reduction of 21% in the fuel required to transport a container, and 1.4% in the total fuel required to move the vehicles, cargo, and containers can be achieved. It was determined that a 10% reduction in mass of the system will result in a fuel reduction ranging from 2% to 8.4%, depending on the mode. Globally, container lightweighting can reduce energy demand by 3.6 EJ and GHG emissions by 300 million tonnes CO₂e over a 15-year lifetime.     

The interaction between road traffic safety and the condition of sewers laid under roads

The main objective of this paper is to show how the service condition of the underground pipeline infrastructure, especially sewage systems, may contribute to road surface failures such as subsidence, bulging and particularly collapse. The analysis was based on CCTV surveys conducted in Poland to investigate the causes of more than a hundred road surface collapse incidents.The method proposed in this paper enables us to determine the risk of road surface collapse as the product of the category of probability of road collapse caused by damaged sewer pipelines and the weighted arithmetic mean category of their consequences.The key conclusions highlight the causes of road collapse incidents, the scale of the hazards, and the benefits resulting from the application of the proposed method to prioritize roads according to the road collapse risk.     

A comparative study on damage assessment of tubular members subjected to mass impact

This paper focuses on the behaviour of tubular members when subjected to low-velocity mass impact. Particular emphasis is given to the numerical assessment of impact damage and the classification of impact response of tubular members. Damage extents of 12 tubular frame test models were predicted and used for quantifying the modelling uncertainties of the numerical tools. USFOS and ABAQUS software packages were used with beam and shell elements, respectively. Based on the test results and the parametric studies performed, the influence of the geometrical parameters and the interaction between the local shell denting and the global beam deformation modes are discussed. A classification of the impact response of the tubular members based on their relative resistance against shell denting and beam plastic collapse load is proposed. Finally, existing analytical models for each energy dissipation mode are visited and modifications are proposed.     

A Value-at-Risk (VAR) approach to routing rail hazmat shipments

Hazardous materials (hazmat) accidents are rare though the consequences could be disastrous. Given the possibility of low probability – high consequence event, a risk-averse routing hazmat shipment is necessary. We propose a value-at-risk (VaR) approach to route rail hazmat shipments, using the best train configuration, over a given railroad network with limited number of train services such that the transport risk as measured by VaR is minimized. Freight train derailment reports of the Federal Railroad Administration were analyzed to develop expressions that would incorporate characteristics of railroad accidents, and then to estimate the different inputs. The proposed methodology was used to study several problem instances generated using the realistic network of a railroad operator, and to demonstrate that it is possible to develop different routes for shipments depending on the risk preference of the decision maker.     

海损散货船艏部舱室型线测量

海损船舶修理是修船企业重要的产值及利润增长点,而船舶首部是易海损区域,修复海损重要依据是型线图及型值表,由于很多海损船没有保存型线图或型值表,给修理工作带来不便.针对这种情况,文章结合散货船的艏部货舱特点,介绍艏部货舱型线测量的方法.     

基于能量法的船体分段翻身吊装方案优化设计方法

分段翻身吊装难度较大,风险较高,目前主要依靠人工经验设计吊装方案,较少有针对分段翻身的优化设计研究。论文首先对翻身过程中吊绳与相关船体构件的典型干涉问题做出干涉评估并提取干涉约束,结合吊点适应度约束确立若干吊点布置方案。然后以在翻身过程中结构的最大应变能最小为优化目标,得到最优吊点布置方案。最后使用结构分析软件验证最优方案的可靠性。     

静力触探CPT在水力吹填砂土地基承载力评估中的应用

为了更好控制科威特LNGI工程水力吹填砂土地基质量,合理评估水力吹填砂土地基处理后的承载力,选取基于CPT的3种经验公式,计算满足设计承载力200 kPa作用下所需的最小锥尖阻力qc值。结果显示,Bowles(1996)法和BS EN1997-1:2004 Annex D推荐法计算的最小qc值与水力吹填质量等级有关,但两者结果较接近,而EslaamizaadRobertson(1996)法计算的结果较小,仅为3. 8 MPa。基于保守考虑,最终结果取前两种方法平均值中的最大值7. 5 MPa。同时基于现场实际,在地基处理后预先进行CPT检测,得到平均锥尖阻力远大于计算验收值,并由大型载荷板ZLT试验验证了满足长期沉降的设计承载力。可见,在地基处理后可预先采用CPT对处理后地基处理承载力进行评估并辅助少量大型ZLT试验进行验证,可有效对地基承载力进行验收。