体外预应力加固简支梁实例计算分析

通过某机房改造工程,介绍了体外预应力加固简支梁在工程中的应用.采用直接计算承载力增量的计算方法,对体外预应力钢绞线所提供承载力增量进行计算分析.结果表明,体外预应力加固简支梁可以有效地提高结构的承载能力,同时也提高了结构的正常使用极限状态.采用直接计算承载力增量的方法比传统计算方法简便,计算公式直观,结果可信.     

Prediction models for sewer infrastructure utilizing rule-based simulation

Management of infrastructure projects is becoming increasingly challenging due to inherent uncertainties. The most effeective way to deal with uncertainty is to collect supplementary information and knowledge. When expensive or infeasible, quantification of uncertainty may be performed using analytical or simulation techniques. The City of Edmonton, Canada has approximately 4600 km of sewer pipes in the combined, sanitary, and storm sewer local systems with uncertainty issues related to deterioration. The City has taken a proactive approach with respect to sewer rehabilitation, as it is more cost-effeective to repair a defective pipe prior to failure rather than after a collapse. This article demonstrates an approach for predicting the condition of a sewer pipe and the related cost of rehabilitation, given the limited data. Three models are described in this article that are developed to assist the City of Edmonton to effeectively plan maintenance expenditure. Each model uses a combination of rule-based simulation and probability analysis to assist in the planning of future expenditures for sewer maintenance, thereby producing an invaluable planning tool.     

Quality assurance and quality control practices for rehabilitation of sewer and water mains

As part of the US Environmental Protection Agency (EPA)'s Aging Water Infrastructure Research Program, several areas of research are being pursued including a review of quality assurance and quality control (QA/QC) practices and acceptance testing during the installation of rehabilitation systems (USEPA 2011). The objectives of this research effort were to collect, analyze and summarize information on the installation and QA/QC practices for the trenchless rehabilitation of sewer and water transmission mains. In addition, consideration was given to practices related to water service lines, sewer service laterals, force mains, siphons, sewer manholes, pumping stations, associated wet wells and other appurtenances. This review was accomplished primarily by conducting interviews directly with rehabilitation technology vendors, design engineers and water and wastewater utilities that have a track record of using trenchless rehabilitation technologies within their network. This paper provides an overview of how QA/QC issues have been handled in North America for trenchless rehabilitation technologies.     

Multidimensional benefit–cost evaluation of asphaltic concrete overlays of rigid pavements

Using the data from a national study in the USA, this study demonstrated a comprehensive and multidimensional pavement treatment evaluation methodology and used the methodology to evaluate the short-term and life cycle cost-effectiveness (CE) of five rigid pavement rehabilitation treatments. Four measures of effectiveness were used in this study: the sudden decrease in surface roughness, treatment service life, increase in average pavement condition over the service life and the area bounded by the performance curve. This study established relationships that quantify the influence of pre-treatment condition on treatment effectiveness. Also, the models were developed to describe the treatment effectiveness as a function of traffic loading and climatic severity. It is seen that at high traffic loading, there is relatively little difference in treatment effectiveness across various climate severities. This study suggests that superior effectiveness of a treatment does not necessarily translate into superior CE. Also, the treatment location was found to influence the relative effectiveness of the treatments. Overall, the results suggest that treatment ‘crack-and-seat and 8-in. asphalt concrete overlay’ is the most cost-effective.     

Decision support model for selection of rehabilitation methods of water mains

The deteriorating condition of water mains in Canada and US calls for rehabilitation strategies that accounts mainly for budget and level of service constraints. These water mains have received ‘D’ grade in the two countries. Decision support models can assist decision makers regarding when to rehabilitate and whether to repair, renovate or replace section(s) of water mains. The literature indicates that decision models should account for life cycle cost, uncertainty, long-term planning, targeted levels of service and budget constraints. The objectives of this paper are to: identify and group rehabilitation methods, present decision support model to rank and select most suitable rehabilitation method(s), and study the impact of rehabilitation methods on the functional and structural performance of water mains. The developed decision support model accounts for life cycle cost of each competing scenario along with the associated uncertainty. The model, unlike available models, can effectively account for vagueness, qualitative assessments and human judgment associated with input data. A case study of a water main network was analysed in order to demonstrate the use of the developed model and to illustrate its essential features. The results obtained indicate that the model can support the generation of well-informed decisions in a timely manner.     

中国土地整理与生态环境保护

在中国土地整理进展情况的基础上,提出了通过土地整理加强生态环境保护的必然性,分析了在土地整理中应遵循的生态系统原理及思路。指出土地整理的出发点应基于生态系统原理(时间、位置、物种、干扰和景观) ,核心是实现整理区生态系统的良性循环。在土地整理的生态分析中,应重点关注土地质量及其可持续性、项目区内外生态系统的连续性、景观的协调性及生物多样性的保护等问题。     

浅议科学发展观对土地整理理念的指导作用

中共中央十六届三中全会正式提出了以“五个统筹”为主要内容的科学发展观。科学发展观将是今后指导我国社会全面健康发展的重要理念,也对当前开展的土地整理工作提出了更高要求。本文在介绍科学发展观基本内容、本质和特征的基础上,分析了科学发展观与土地整理的关系,全面论述了土地整理规划、土地整理项目的立项、规划设计和项目实施管理对落实科学发展观的作用。     

某小区加固与改造方案浅析

针对某小区建筑物的累计沉降量过大引起房屋的质量问题,分析其小区主体结构和基础上的原因,结合用户需求,提出了较为合理的加固、拼接方案.     

5 DOF穿戴式上肢康复机器人控制方法研究

提出了一种面向偏瘫患者,可实现单关节和多关节运动的5自由度穿戴式上肢康复机器人的控制新方法.根据偏瘫患者上肢单侧受损的特点,该机器人利用偏瘫患者的健肢运动的表面肌电信号(sEMG)驱动康复机械臂辅助患者患肢实现康复训练.利用肌电绝对值积分(IAV)和自回归参数模型法(AR model)对选定的上肢四块肌肉运动产生的sEMG信号进行分析,所提取的特征分别作为基于Levenberg-Marquardt算法的反向传播神经网络的输入,6个上肢运动作为输出建立表面肌电信号与上肢康复动作之间的关系.试验结果表明该方法利用sEMG准确地完成了对上肢康复动作的识别.这一方法有利于提高患者运动积极性,保持正确运动的感觉,并为研究患者受损上肢表面肌电信号与肌肉运动的关系打下了基础.     

Enhancing Post-Stroke Rehabilitation and Preventing Exo-Focal Dopaminergic Degeneration in Rats—A Role for Substance P

Dopaminergic signaling is a prerequisite for motor learning. Delayed degeneration of dopaminergic neurons after stroke is linked to motor learning deficits impairing motor rehabilitation. This study investigates safety and efficacy of substance P (SP) treatment on post-stroke rehabilitation, as this neuropeptide combines neuroprotective and plasticity-promoting properties. Male Sprague Dawley rats received a photothrombotic stroke within the primary motor cortex (M1) after which a previously acquired skilled reaching task was rehabilitated. Rats were treated with intraperitoneal saline (control group, n = 7) or SP-injections (250 µg/kg) 30 min before (SP-pre; n = 7) or 16 h (SP-post; n = 6) after rehabilitation training. Dopaminergic neurodegeneration, microglial activation and substance P-immunoreactivity (IR) were analyzed immunohistochemically. Systemic SP significantly facilitated motor rehabilitation. This effect was more pronounced in SP-pre compared to SP-post animals. SP prevented dopaminergic cell loss after stroke, particularly in the SP-pre condition. Despite its proinflammatory propensity, SP administration did not increase stroke volumes, post-stroke deficits or activation of microglia in the midbrain. Finally, SP administration prevented ipsilesional hypertrophy of striatal SPergic innervation, particularly in the SP-post condition. Mechanistically, SP-pre likely involved plasticity-promoting effects in the early phase of rehabilitation, whereas preservation of dopaminergic signaling may have ameliorated rehabilitative success in both SP groups during later stages of training. Our results demonstrate the facilitating effect of SP treatment on motor rehabilitation after stroke, especially if administered prior to training. SP furthermore prevented delayed dopaminergic degeneration and preserved physiological endogenous SPergic innervation.