消能技术的发展及宽尾墩联合消能工浅析

本文介绍了泄洪消能技术的发展,主要从改进常见的底流和挑流消能方式;采用新型消能工;联合多种消能工等方面进行.此外还对宽尾墩联合消能工进行了较为系统的研究,介绍其分类,消能机理并通过一工程实例论证其消能效果.     

某水库溢洪道消力池消能墩墩型和位置优化研究

消力池是水利工程泄水建筑物的重要组成部分,其结构优化对保证水利工程的安全稳定运行具有重要意义.文章以某小型水库为例,利用工程模型试验的方式,探讨了不同消能墩墩型和位置对消力池消能效果的实际影响,并根据试验结果对工程设计提出了建议.     

中坝子水电站表孔泄洪消能建筑物体型试验研究

对中坝子水电站表孔泄洪消能建筑物布置体型进行试验研究,得出在河谷狭窄地区的中小拱坝表孔设计时,可采用宽尾墩体形使水舌在纵向范围扩散,充分利用消能空间与水体,避免平尾墩的边孔横向扩散水流冲砸岸坡,既适应了不同流量洪水泄洪的要求,又使消能率得到大幅度提高,消能防冲流量泄洪时冲坑深度可减小27.2%。     

利俩水利枢纽排洪道消能方案研究

结合"利俩水利枢纽水工整体模型试验”的研究成果,对排洪道消能方案的选择进行了深入的分析论述.经研究推荐的宽尾墩加小斜坎结合反坡挑坎的联合消能布置形式,较好解决了该类型排洪道的消能问题,效果良好.     

混凝土四面六边透水框架在坝下消能设计中的应用

1　四面六边透水框架的工作机理传统的消能防冲技术绝大部分为实体抗冲防护 ,如抛石或抛混凝土 (实心 )四面体、干砌石护坡、浆彻块石护坡、丁坝、顺坝、沉排、土工枕、混凝土膜袋等。当水流以一定的能量冲击实体材料 ,按照能量守恒原理 ,其原有的能量将转变 ,形成螺旋流、回流等 ,这将淘刷工程基础 ,造成抛石滑动、翻滚、坍塌 ,致使工程失稳 ,出现工程事故。另一类消能防冲技术如杩杈、挂柳、钢筋混凝土网格排 ,其工作机理有别于上述情况 ,即局部改变水流的流态 ,利用其本身分散水流自相消杀能量 ,从而达到消能防冲保护工程目的。钢筋混凝…     

应用射流理论研究面流消能

本文应用射流理论来解释面流流态的演变过程, 并深入探讨回复底流流态的水流结构、形成机理及其与面流相互转化的条件.     

塔吊在公路工程薄壁墩中的应用分析

随着我国经济的高速发展,各种公路工程越来越多,对工程建设要求也在不断提升。公路桥梁工程施工是公路工程施工的重要组成部分,薄壁墩的施工是其中的关键点也是难点,对施工质量往往有着比较高的要求,为了提升对薄壁墩的施工质量和效率,可以将塔吊施工技术有效应用其中。分析塔吊在公路工程薄壁墩中的应用,希望可以促进工程事业的发展。     

某重点输水工程取水首部调流消能阀模型试验研究

辽宁省某重点输水工程取水首部选用DN2400大口径调流消能阀,该类型口径消能阀在国内没有实际应用先例,因此借助模型试验对调流阀进行仿真试验并对原型机设计进行了验证和安全评估.按照几何相似原则选定模型几何比尺为1:9.6,模型阀型规格选定DN250对原型机进行仿真模拟实验,结果表示,DN2400大口径的调流消能阀可以达到...     

综合消能方式在表孔溢洪洞末端的应用与研究

工程在表孔溢洪洞末端采用挑流、消力塘、台阶式陡坡、消力池及泄洪渠等综合消能方式,通过连续四次消能,解决了泄洪建筑物末端因泄流角度、地形高差、水流归槽等因素而不能使下泄水流安全稳定进入天然河道的问题,解决了泄水建筑物末端水流消能的技术难题。     

MAX6641在笔记本电脑散热系统中的设计

MAX6641是微机散热保护专用智能集成温度传感器。介绍了基于单片机与MAX6641传感器在笔记本电脑散热系统中的设计。本次设计可以在笔记本电脑散热系统中实现5级风速调节。采用MAX6641传感器作为温度检测元件;单片机用来完成温度的模糊控制,并通过串行总线调节MAX6641内置的PWM(脉宽调制)寄存器,继而控制直流电机风扇转速。测温范围为35~65℃,分辨率为±1℃。     

百色水利枢纽消力池工程地质研究

百色水利枢纽消力池地基工程地质条件较差,存在严重的不均匀变形问题,通过大量的勘探试验研究工作,查明了消力池区的工程地质条件,对存在的工程地质问题进行了准确评价,为设计提供合理的地质参数和建议。     

Nutrition,agriculture and the global food system in low and middle income countries

The entire food value chain and diet of low and middle income countries (LMICs) are rapidly shifting. Many of the issues addressed by the nutrition community ignore some of the major underlying shifts in purchases of consumer packaged foods and beverages. At the same time, the drivers of the food system at the farm level might be changing. There is a need for the agriculture and nutrition communities to understand these changes and focus on some of their implications for health. This rapid growth of the retail sector will change the diets of the food insecure as much as that of the food secure across rural and urban LMIC’s. This short commentary contents that current research, programs and policies are ignoring these rapid dynamic shifts.     

全球定位系统（GPS）技术在水利工程中的应用

结合全球定位系统（GPS）测量技术在水利工程中的测量应用原理,对其在渭干河流域水下地形测量、新疆吐鄯托盆地某大型水库测量项目中的测量实践进行了相应的探讨,并提出了应用中存在的技术问题,以供同行参考。     

Urban crowdsourcing: Stakeholder selection and dynamic knowledge flows in high and low complexity projects

Urban crowdsourcing is a new form of open innovation that aims to develop smart cities. Due to the heterogeneity of partners in urban planning, knowing the type of knowledge gained from each stakeholder at each stage of the crowdsourcing process needs to be understood for effective collaborations and innovative knowledge flow activation. Using a qualitative approach with experts involved in the Casablanca Smart City project, this research investigates complex multi-stakeholder ecosystems. More specifically, this study identifies and examines the role of external stakeholders at each stage of the innovation process, and the resulting dynamic knowledge flows that help improve the process of urban crowdsourcing in the development of smart city solutions. Depending on the complexity of the innovation project, findings identify three primary stakeholders (citizens, public authorities, and private and public firms) and three secondary stakeholders (NGOs, universities, consulting companies). Results show at which of the four steps of urban crowdsourcing they intervene. Furthermore, the findings reveal a dynamic learning environment composed of two knowledge flows (“learning with” and “learning from” stakeholders).     

Agricultural pesticides and land use intensification in high,middle and low income countries

We study levels and trends in agricultural pesticide use for a large cross-section of countries using FAO data for the period 1990–2009. Our analysis shows that a 1% increase in crop output per hectare is associated with a 1.8% increase in pesticide use per hectare but that the growth in intensity of pesticide use levels off as countries reach a higher level of economic development. However, very few high income countries have managed to significantly reduce the level of intensity of their pesticide use, because decreases in insecticide use at higher income levels are largely offset by increases in herbicide and fungicide use. The results also show very rapid growth in the intensity of pesticide use for several middle income countries such as Brazil, Mexico, Uruguay, Cameroon, Malaysia and Thailand. Complementing our analysis with data from the Rotterdam Convention on Prior Informed Consent (PIC), we show that hazardous pesticides covered in the PIC procedure are more weakly regulated in lower than in higher income countries. We discuss the policy challenges facing developing countries with a rapid growth in pesticide use and recommend a four-pronged strategy, including an environmental tax on pesticides with revenues allocated to long-term investments in awareness building, the development of integrated crop management methods and the setting of food safety standards. The interactions between these measures should help contribute to the effectiveness of the overall strategy package.     

以量化评分方法开展水利工程质量检查

1前言 2004年辽宁省水利工程质量监督中心站对全省15项水利工程进行了质量检查,这是辽宁省首次采用量化评分方法对水利工程质量进行的检查,分析总结其经验,对今后开展类似的工程质量检查必将大有裨益.