Environmental microscopy in stone conservation

The natural weathering of stone is accelerated by the combined effects of acid rain, salt crystallization, and the freeze-thaw cycles of water. Since weathering will take place until the system reaches chemical equilibrium, we can mitigate the loss to historic stone monuments and structures by treatments of the stone that retard hydrolysis and impart mechanical strength. While macroscopic studies of stone weathering have been performed addressing the causes, the reactions, and the kinetics involved, the mechanisms of weathering, and the chemical remediation of stone need to be better understood at a microscopic level. Our approach uses environmental scanning electron microscopy where samples can be imaged in their wet, natural state, thus facilitating the in situ study of the weathering processes. The environment in the microscope is set up to simulate the conditions of degradation by introducing corrosive liquids and gases and varying the temperature, pressure, and water content in the environmental chamber of the microscope. In this study, we observed specimens of limestone, treated calcite, and sandstone. We have characterized the morphology, structure, and chemical constituents of the samples for comparison at a later stage when protective coatings will be applied. In situ leaching tests were performed on limestone samples to study the mechanisms of degradation. Granular disintegration due to leaching of the binding material between the grains was seen. We have also observed, in situ, the changes in the structure of sodium sulfate, used in salt crystallization tests, during hydration and dehydration cycles; it changed from that of dense grains to hydrated mesoporous granules with the generation of new surface area.     

鄂尔多斯地块油区构造演化特征

鄂尔多斯地块经历了６大构造演化阶段，各阶段具有不同的构造格局和沉积特征。研究认为：多旋回的演化历史、古构造格局、构造变形特征及重要的侵蚀间断对油气藏的形成与分布有明显的控制作用。     

鄂尔多斯盆地中部古地貌与构造对气藏的控制作用

鄂尔多斯盆地中部气田形成于稳定克拉通中央古隆起东坡，是一个与海相碳酸盐岩有关的风化壳型气田。采用补偿厚度印模法及残留厚度法恢复古地貌，着重分析古地貌与构造因素对气藏形成的控制作用，讨论了田形成机制及天然气富集规律。     

MgF_2镀膜对 ZrF_4-BaF_2-AlF_3-YF_3系统玻璃耐侯性的影响

本文采用红外透射光谱、红外反射光谱、扫描电子显微镜、X 射线能量色散谱仪等方法研究了表面蒸镀 MgF_2镀膜对 ZBAY 系统玻璃耐风化性能的影响,并对该玻璃试样风化侵蚀机理和水化侵蚀机理进行了比较。实验结果表明:ZBAY 系统玻璃的风化侵蚀机理和水化侵蚀机理并不完全相同。ZBAY系统玻璃在较强的风化条件下和较强的水化条件下发生严重的侵蚀。而 MgF_2镀膜能够有效地改善ZBAY 系统玻璃的耐风化和耐水侵蚀性能。     

Oxidation states in surface and buried coal from the Fording River Deposit

A suite of five representative samples from a freshly opened adit in the Fording River Coal Deposits, BC was taken at selected distances from the surface to the 45.7 m depth of the seam to provide material for studying the progress of coal oxidation under natural conditions. The ‘as-mined’ < 28 US mesh material from each sample was subjected to standard proximate, ultimate and free swelling index (FSI) analyses, followed by quantitative evaluation of surface oxidation states, using several techniques concurrently. Correlation of the results indicates a progressive decrease in oxidation from a very high level for the surface sample, with FSI 1, to a relatively low oxidation level for samples taken at 22.9 m and 45.7 m distances. Solvent extracts show a progressive decrease in the ratio of soluble aliphatic-to-aromatic compounds from surface to deep coal and in the amount of carboxylate groups. Oxidized coals require pretreatment with dilute acids in order to convert phenolate and carboxylate salts into phenols and carboxylic acids respectively; the analytical results for the latter are then increased by a factor of 4–6.     

超大断面海底隧道穿越风化槽施工及方案研究

以厦门翔安海底隧道A3标穿越风化槽处理方案为例,针对施工中存在的技术难题,从地质预报、帷幕注浆、开挖支护、监控量测等方面详细阐述了施工方案,并指出施工中应注意的问题,从而为类似工程积累施工经验。     

四川盆地磨溪地区灯四段风化壳岩溶储层特征

近年来,四川盆地磨溪地区灯四段的油气勘探取得了重大突破,为研究磨溪22井区灯四上亚段优质岩溶储层特征及分布规律,开展了岩心分析、物性测试、地震资料解释、测井分析和有利岩溶储层发育区预测等工作。结果表明：①岩溶储层的岩性主要为藻云岩类、砂屑云岩类和结晶云岩类,储集空间主要为溶蚀孔、溶洞和裂缝;②溶蚀作用包括同生期大气淡水的溶蚀作用、埋藏期深部热液溶蚀作用和有机酸的溶蚀作用、表生期大气淡水的溶蚀作用;③表生期的溶蚀作用控制了优质储层的分布,多发育于垂直渗流带附近和水平潜流带上部区域,平面上优质储层的分布受控于沉积相带和古地貌特征,以丘滩相和溶丘斜坡较好。该研究成果为磨溪地区下一步勘探指明了方向。     

风化火山期次界面识别及控藏作用——以西准噶尔地区为例

西准噶尔地区风化火山期次界面分为两类,Ⅰ类界面自然伽马值高、电阻率值低、密度值低;Ⅱ类界面自然伽马值高、电阻率值高、密度值低。界面发育在火山机构的分界线上,地震剖面上具有超覆、强反射的特征。风化火山期次界面为流体的运移通道,流体对界面两侧的岩石产生强烈的风化作用,使界面附近岩石内部产生微裂缝、溶蚀孔洞,最终使风化火山期次界面区域成为油气成藏的优势区域。     

渤海深层变质岩潜山油藏裂缝主控因素及预测

渤中13-2大型潜山地区是渤海海域发现的首个亿吨级深层变质岩潜山油藏.通过已钻井的岩心、薄片、测试、测井等资料,从构造演化、成岩作用、古地貌特征等方面,阐述了研究区潜山储集空间类型、裂缝发育主控因素及分布规律,为研究区的高效开发奠定基础.研究结果表明:①多期次构造运动是导致裂缝形成的主控因素,风化淋滤和裂缝充填是造成储...     

Analysis of degradation mechanisms of crystalline silicon PV modules after 12 years of operation in Southern Europe

The long‐term reliability of photovoltaic modules is crucial to ensure the technical and economic viability of PV as a successful energy source. The analysis of degradation mechanisms of PV modules is key to ensure current lifetimes exceeding 25 years. This paper presents the results of the investigations carried out on the degradation mechanisms of a crystalline silicon PV installation of 2 kWp after 12 years of exposure in Málaga, Spain. The analysis was conducted by visual inspection, infrared thermography and electrical performance evaluation. By visual inspection, the most relevant defects in the modules were identified and ranked according to their frequency. The electrical performance was assessed by comparing the characteristic parameters of the individual modules, obtained by outdoor measurements at the start and end of the exposure period. The correlation of the visual defects and the shifts in the electrical parameters was analysed. The results presented show that glass weathering, delamination at the cell‐EVA interface and oxidation of the antireflective coating and the cell metallization grid were the most frequently occurring defects found. The total peak power loss, including the initial light induced degradation, was 11.5%, which corresponded almost totally to a loss in short‐circuit current. Copyright © 2011 John Wiley & Sons, Ltd.