Reducing the Compaction Segregation of Hot Mix Asphalt

This paper presented the methods of reducing the compaction segregation of asphalt layer by improving the operating characteristics of roller and paver. The fit formula, which expresses the compaction rule of the paving layer after passing different rolling passes of the steel wheel roller, was also put forward. The measured results of test road show that when some technical methods are adopted, the compaction segregation can be controlled.     

不同性质城市广场绿化面积比例分析研究

比例是部分对全体在尺度间的调和.城市广场的性质不同,其活动内容和活动对象不同,绿化要求也不同,从而影响到广场的绿化面积比例.广场性质是其绿化面积比例的决定性因子之一.笔者以13个城市的58个城市广场为研究对象,对不同性质广场的绿化面积比例进行了定量分析,针对目前已经出台的国家和地方的相关规范、条例和办法中有关城市广场绿化面积比例的指标要求,进行对比分析,结合绿化面积比例和功能布局满意度的实地调查结果,探讨了指标指导和异质异标原则、绿量补偿、水平和竖向双重评价原则等问题.     

再生水行业最优资本结构的实证研究

确定最优资本结构对再生水项目的融资和行业发展具有重要的意义，本文采用基于公司股票价值最大化的最优资本结构研究模型，结合上市公司数据对再生水行业的最优资本结构进行实证分析，旨在为再生水行业的项目融资安排提供参考。     

Towards an optimised lab procedure for long-term oxidative ageing of asphalt mix specimen

Ageing of bitumen leads to increased stiffness and brittleness. Thus, bituminous bound pavements become more prone to failure by low-temperature and fatigue cracking. Therefore, the ageing behaviour of bitumen has a crucial impact on durability, as well as recyclability of pavements. To assess ageing of bitumen, the rolling thin film oven test and pressure ageing vessel are standardised methods for short-term and long-term ageing in the lab. For lab-ageing of hot mix asphalt (HMA), various methods have been developed in the last decades. This paper presents a study on the potential of employing a highly oxidant gas for simulating the long-term oxidative ageing of asphalt mix specimens in the lab. Based on the results, an optimised lab-ageing procedure (Viennese Ageing Procedure – VAPro) for compacted HMA specimens to assess mix performance of long-term lab-aged specimens is developed. Thus, it is possible to optimise mix design not only for short-term performance but to take into account effects of oxidative ageing during its in-service life. VAPro is based on a triaxial cell with forced flow of a gaseous oxidant agent through the specimen. The oxidant agent is enriched in ozone and nitric oxides to increase the rate of oxidation. It is shown by stiffness tests of unaged and lab-aged specimens, as well as by Dynamic Shear Rheometer tests of recovered binder from aged specimens that asphalt mixes can be long-term aged at moderate temperatures (+60°C) and within 4 days and a flow rate of 1 l/min by applying VAPro. Thus, an ageing procedure is at hand that can simulate long-term ageing at conditions that are representative of conditions that occur in the field within an efficient amount of time.     

R&D policy instruments – a critical review of what we do and don’t know

In recent years, the term “policy instrument” has been used frequently with regard to R&D policy and innovation policy. This article examines the development of the term as part of a body of research known as “policy design”. Over the last 50 years, there has been substantial progress in setting policy design on a more systematic basis, with the development of established concepts and analytical frameworks, including various taxonomies of policy instruments. However, with just a few exceptions, this body of research seems to have had little impact in the world of R&D policy. The paper reviews the literature on R&D policy instruments, identifies a number of challenges for R&D policy instruments in the light of four transitions and sets out a research agenda for the study of R&D policy instruments, before ending with a number of conclusions.     

Investigating the effect of training–testing data stratification on the performance of soft computing techniques: an experimental study

Abstract

Cross-validation of soft computing techniques needs to be done efficiently to avoid overfitting and underfitting. This is more important in petroleum reservoir characterisation applications where the often-limited training and testing data subsets represent Wells with known and unknown target properties, respectively. Existing data stratification strategies have been haphazardly chosen without any experimental basis. In this study, the optimal training–testing stratification proportions have been rigorously investigated using the prediction of porosity and permeability of petroleum reservoirs as an experimental case. The comparative performances of seven traditional and advanced machine learning techniques were considered. The overall results suggested a recommendable optimum training stratification that could serve as a good reference for researchers in similar applications.     

戈枕水利枢纽工程混凝土施工配合比的优化

戈枕水利枢纽工程通过优化调整混凝土施工配合比,改变了混凝土观感,降低了单方成本,有效延缓并降低了坝体内部混凝土水泥水化热温升。通过工程实例,强调了优化混凝土施工配合比的重要性。     

电动三通比例阀三维湍流数值分析及优化控制

为分析管路系统中三通比例阀的流量特性,对三通比例阀进行了三维流场数值计算。当三通阀用作分流时,分析了出口流量比和出口水头损失率随入口雷诺数及阀芯位置的变化规律;当用作合流时,分析了入口流量比随出入口压力差及阀芯位置变化规律。结果表明:比例阀的各口流量比主要受阀芯位置影响,在三通比例阀中腔体形状、壁面糙度一定的情况下,降低入口雷诺数可减小局部阻力损失。实现了基于流量比特性曲线的优化控制。     

浅谈麦海因水库中“浇筑式沥青混凝土心墙”的设计

“浇筑式沥青混凝土心墙”作为大坝的防渗体以其较低的造价,较好的防渗效果在当地水库建设中被广泛采用.对麦海因水库中沥青混凝土心墙的结构设计和沥青混凝土心墙配合比设计进行了简要说明.     

褐煤炉渣生产免蒸免烧砖试验研究

以内蒙古赤峰市第二毛纺厂排出的褐煤炉渣为主要原料，研制生产免蒸免烧砖，试验通过５０多组、成型了４５０ 多块试件，对该种砖的抗压性能、抗折性能及抗冻性能进行了测试，同时对所用原材料进行了物理和化学成份测试，重点研究了不同加压情况下、多组配合比时砖的抗压强度，同时研究了外加剂的作用及最佳掺量，通过正交试验最终研制出经济技术合理，生产抗压强度为１０ ＭＰａ 以上，与普通粘土砖物理力学性能相当的，具有明显的节能、利废效果的非烧结免蒸粉煤灰砖的配合比和生产工艺，为大批量生产提供技术保障。