广东省海堤规划工程环境影响分析及对策

对海堤工程所产生的环境影响进行分析 ,并提出减轻不利影响的对策措施 ,以保证工程充分发挥其效益。     

圆管空拔壁厚变化分析

此文利用主应力法推导出圆管空拔壁厚变化量解析式。该式计算结果与以定常三维流动上界解析同类问题结果相接近,且表达式简单,也与拔管的实验结果相一致。因而,可在圆管空拔壁厚计算时推广应用。     

Concentration level of heavy metals in the Great Wall Bay, Antarctica in austral summer

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Air ventilation impacts of the “wall effect” resulting from the alignment of high-rise buildings

The objective of this study is to investigate the air ventilation impacts of the so called “wall effect” caused by the alignment of high-rise buildings in complex building clusters. The research method employs the numerical algorithm of computational fluid dynamics (CFD – FLUENT) to simulate the steady-state wind field in a typical Hong Kong urban setting and investigate pollutant dispersion inside the street canyon utilizing a pollutant transport model. The model settings of validation study were accomplished by comparing the simulation wind field around a single building block to wind tunnel data. The results revealed that our model simulation is fairly close to the wind tunnel measurements. In this paper, a typical dense building distribution in Hong Kong with 2 incident wind directions (0° and 22.5°) is studied. Two performance indicators are used to quantify the air ventilation impacts, namely the velocity ratio (VR) and the retention time (T_r) of pollutants at the street level. The results indicated that the velocity ratio at 2 m above ground was reduced 40% and retention time of pollutants increased 80% inside the street canyon when high-rise buildings with 4 times height of the street canyon were aligned as a “wall” upstream. While this reduction of air ventilation was anticipated, the magnitude is significant and this result clearly has important implications for building and urban planning.     

九龙壁石的显微结构和元素分析

福建九龙江流域分布的九龙壁石,经分析为透辉石矽卡岩,主要成分为透辉石,斜长石及石英等构成.其化学元素为Si、Ca、Al、Fe、Mg等24种.九龙壁石花纹美丽,可作工艺品等.     

薄壁三通管翻边成形工艺参数的确定

介绍了薄壁三通管翻边成形时预制孔形状及极限翻边高度的确定方法。     

Hydrogen explosion incident mitigation in steam reforming units through enhanced inspection and forecasting corrosion tools implementation

Hydrogen (H₂) explosion effects recently examined, are confirming the devastating loss scenarios to humans, environment, assets, and associated business interruption. H₂ production is a core process in refineries used in further process steps. Steam reforming of natural gas or a mix with naphtha or LPG is a common hydrogen production technique, where the latest technologies have adopted enhanced metallurgies to minimize explosion risk and the associated maintenance cost following plant degradation owing to corrosion effects. However, corrosion rates are still high in specific areas of piping and process equipment. The aim of this paper is to present a methodology based on semi-quantitative RBI modeling according to regulations by API and recent EN standards, adopting a family of linear regression forecasting models that depict the yearly corrosion rate (per corrosion loop) of a hydrogen production steam reforming unit; this is done under different operating conditions (e.g., temperature, pressure, and fluid speed), metallurgy and other related physicochemical variables. The model is based on the examination of both ultrasonic wall thinning measurements and the examination of quantitative crosslinking total corrosion effects along with the physicochemical properties prevailing in different plant corrosion loops. The outcome of the regression analysis is an expansive family of multivariable equations describing, with a defined accuracy, the yearly corrosion rate and associated lifespan forecast per corrosion loop, and per examined part. These equations were further utilized in a custom-made database that can be used as an additional loss prevention tool by the hydrogen production unit management team. Evaluation results regarding the tool efficiency are presented in the following of this paper.     

中国长城沿线生态脆弱性分析及生态保护对策

中国长城沿线是半湿润—半干旱和半干旱—干旱气候的过渡地带,也是农牧业的交错地带,生态极其脆弱,生态压力又大,容易发生生态破坏,而且很难恢复。为了保护中国长城沿线的生态环境,必须调整产业结构,合理布局,采用先进技术,加大投入,提高生态意识,加强法制建设。     

承压类特种设备受压元件壁厚测定问题的探讨

壁厚是承压类特种设备结构的主要参数.针对几例因受压元件壁厚未测定所留下的安全隐患,本文对承压类特种设备壁厚测定的必要性进行分析探讨,并分别就锅炉、压力容器和压力管道在相应法规标准中对壁厚测定的要求和对监检机构的要求提出了建议.     

“挡风抑尘墙”技术研究及其应用

内蒙古天晧水泥有限公司将＂挡风抑尘墙＂技术成功应用在石灰石预均化堆场和煤场,对消减石灰石预均化堆场和煤场风力,抑制石灰石预均化堆场和煤场扬尘起到了很好的作用,解决了大型堆场扬尘治理的一个技术难题。现就＂挡风抑尘墙＂的工作机理、结构特点及其抑尘效果等进行分析介绍,以促进该技术的推广和应用。