The impact of heat-treatment protocol on the grain size and ionic conductivity of NASICON glass-ceramics

Na₂AlTi(PO₄)₃ (NATP) and Na_1.8Al_0.8Ge_1.2(PO₄)₃ (NAGP) NASICON (Na-Superionic Conductor) glass-ceramics are obtained by applying different single (SHT) and double (DHT) heat treatments on the respective precursor glass to evaluate its effect on the microstructure and in turn, on the total ionic conductivity. The grain and grain boundary contributions are also analyzed in the NATP composition. SHT with longer crystallization times favors the development of well-defined grains in both compositions and also promotes the grain growth in NAGP samples. This behavior causes a decrease in the activation energy of the grain boundary, which enhances the total ionic conductivity. Regarding DHT samples, microstructure with larger grains and higher ionic conductivity were obtained with shorter nucleation times for NATP and NAGP compositions. Finally, the microstructural variation generated by the different thermal treatments causes the total conductivity to increase up to two times.     

45m高砖烟囱控制爆破拆除

介绍了城区45m高砖烟囱的控制爆破拆除。根据实践经验,合理选择爆破方案、爆破参数及防护措施。在没有按照常规方法对余留支撑体下部的烟道口进行封堵的前提下,对爆破切口采取一次性起爆。烟囱按照预先设计的方向倾斜、倒塌,倾倒过程中没有发生后坐现象,取得了较好的爆破效果,可为类似工程的设计与施工提供参考。     

Quantitative and qualitative assessment of musculoskeletal disorders and socioeconomic issues of workers of brick industry in Pakistan

Brick industry, in Pakistan, is prominent and provides job to 3.1 million people only in one province. The industry hires different percentage of workers for different stages of brick formation and these stages trigger musculoskeletal disorders (MSDs) in workers. This study identifies relation between 5 work stages and MSDs in 9 body parts and also finds socioeconomic sufferings inflicted by the industry and removal of research gap at national level. We conducted both qualitative and quantitative research. 105 men and 45 women from 15 brick kilns were selected as subject. Rapid Upper Limb Assessment (RULA) and Rapid Entire Body Assessment (REBA) sheets, Standard Nordic MSDs Questionnaire along with general questionnaire, still photography and video recording were used to carry out the study. About 96% workers involved in mixing & molding complained tiredness at end of day. Similarly, 90% male and 83% female staff performing spreading task suffered tiredness after their duty hours. Workers engaged in different tasks reported varying levels of pain in observed body parts. Digging and carrying jobs caused significant pain in body parts including neck, upper back, shoulders, lower back and hips. Mixing and molding emerged most dangerous activities for most of the body parts and exhibited 7 score on RULA. Furthermore, mixing and molding demonstrated high to very high risk level by showing 9 and 13 higher score on REBA, respectively. The current study divulged that all observed work tasks during manufacturing and transportation of bricks are equally dangerous for pain generation in lower back. Many socioeconomic issues like residency of workers in muddy house (83%) low monthly income (<90.3 $) of 83% workers, higher tendency of alcoholism and smoking in men, lack of health facilities and higher illiteracy rate were also identified. The enhanced musculoskeletal disorders during brick making process render the brick industry unhealthy for work. This dismal picture requires an improvement in quality of life and occupational environment of workers of the industry. Well organized duty timings, modified working posture, job rotation and preliminary training perhaps manage these miseries and the output of the brick industry may increase many fold.     

砌体本构关系的研究进展

介绍国内外砌体结构本构关系的研究现状和发展趋势,归纳砌体本构关系的各种类型及影响因素．根据实验数据的回归分析,得到混凝土多孔砖砌体受压本构关系的表达式．通过对国内外学者提出的不同本构关系进行比较和分析,给出了各本构关系的实用价值及存在问题,这是砌体结构内力分析、强度计算及有限元分析时必不可少的依据．最后,提出了砌体本构关系研究中存在的一些问题以及需要进一步完善的地方．     

砖艺营造浅谈

中国的砖艺是建筑空间造型的“基本词汇”,是劳动人民为适应生活需要和审美要求就地取材而创作的。它广泛地进入人民的生活,并与其他传统工艺美术一样,通过艺术实践的革新,创造出完善的风格。其中的画像砖最是富于审美意义,它以实用其基本功能,并由于画“像”于砖,使砖的审美价值得到了提升。     

底部框架砌体房屋抗震设计中的几个问题

本文基于底部框架砌体房屋结构易损性分析 ,并结合以往的震害资料及设计实践 ,就这类结构抗震设计中的几个问题进行了研究 ,给出了一些看法和建议 ,供参考     

加气混凝土建筑应用经济分析

加气混凝土制品作为一种新型建筑材料广泛应用于建筑物墙体和屋面中。本文就六层加气砼砌块住宅与六层砖混结构住宅进行经济比较分析，得出结论：加气砼具有质轻、节能、经济等优点，具有广阔的发展前景。     

加气混凝土砌块墙体裂缝分析与设防

金帝花园是国家康居示范工程之一，墙材采用加气混凝土砌块，为提高墙体的砌筑质量，在对墙体裂缝成因分析的基础上提出相应的设防措施，并在工程施工中取得满意的效果。     

Salt damage to brick kiln walls in Japan: spatial and seasonal variation of efflorescence and moisture content

To clarify the mechanism of salt fretting of a brick building, monthly observations were made over one year at a two-storey brick kiln in central Japan. Products of weathering that had fallen were collected and weighed; salts were identified using XRD and the moisture content of the brick was measured at its surface using a portable infrared optical moisture meter. Gypsum (CaSO₄·2H₂O) was found at the bottom of the first floor wall in the warm and humid season. Thenardite (Na₂SO₄) is dominant on the first floor wall; it is abundant in the cold and dry season but sparse in the warm and humid season. Magnesium sulphate is dominant on the second floor wall; epsomite (MgSO₄·7H₂O) was observed in the dry-to-wet season and hexahydrite (MgSO₄·6H₂O) in the wet-to-dry season. Seasonal changes in salt abundance result from the temperature dependence of the solubilities and equilibrium relative humidities (ERH) of each salt. The amount of brick decay material due to salt weathering is much greater from the second floor wall than from the first floor wall and is greater from spring to the end of summer. These seasonal and spatial variations of the rate of brick decay can be explained by a combination of factors: (1) the types of salt, (2) efflorescence or sub-florescence and (3) salt deliquescence.     

上海银河宾馆唐宫海鲜舫室内设计

文章简要回顾了上海银河宾馆唐宫海鲜舫室内设计的主要构思及设计特色与做法,以便于读者更好地理解这个材料使用方式上独特的室内作品的设计观念。