A study of a plan-do-check-act method used in less industrialized activities: two cases from industrialized housebuilding

In construction projects, a large number of deviations are usually found during inspections and adjusted in a reactive manner. For projects to become proactive, root causes need to be identified and eliminated as a part of a process of continuous improvement (CI). Plan-do-check-act (PDCA) methods are part of CI and have been used with success within the manufacturing industry for decades. Research studies of PDCA in construction are less common, which could be explained by the past dominance of the project-based nature of construction compared to the process-based nature of manufacture. Industrialized construction, however, has changed this picture somewhat, and it is of interest to find out how well it works for less industrialized activities in construction. A PDCA method was tested in two cases selected from one medium-sized Swedish industrialized housebuilder, which uses a building system based on offsite manufactured modules. Empirical results are based on systematic data gathered through interviews and participant observations. Results from the two cases show that the PDCA method worked even when processes were divided into industrialized parts within a factory and non-industrial parts at the construction site although this might lead to temporary corrective actions rather than permanent process actions.     

超细水雾全尺寸灭火试验研究

采用超细水雾全淹没灭火装置在3m×3m×3m的全尺寸密闭空间内进行庚烷火灭火试验,从而验证超细水雾在较大密闭空间内灭庚烷火的适用性。试验采用200mL/min和500mL/min的超细水雾灭火装置同时施加超细水雾,试验火源分别使用40kW和120kW的庚烷火,产雾所用的水分别采用纯水和含碳酸氢钠的水溶液,通过四种不同工况验证超细水雾的灭火效果。试验结果表明,超细水雾可扑灭较大密闭空间内的庚烷火,NaHCO3能够显著增强超细水雾的灭火效果。     

Collapse analysis of real RC spatial structures using known failure schemes of ferro‐cement shell models

Large‐span reinforced concrete (RC) shells collapses that occurred in the last decade caused many death toll as well as significant losses to national economies. The most famous cases were the collapse of the aqua park cover in Moscow on February 2004 and the 2E terminal roof destruction at Charles de Gaulle Airport near Paris on May 2004. Following the publications of the appropriate commissions that have studied the reasons of these events, the influence of concrete creep and changes in the shell geometry on buckling of RC thin‐walled shells was not properly considered in the design. This study is focused on buckling of such shells, taking into account geometrical and physical nonlinear behaviour of compressed concrete. Other important reasons of concrete shells collapse are also analysed. The study is based on available experimental and theoretical investigations of ferro‐cement shells' models previously performed by the first author. The results of these investigations, obtained for small‐scale ferro‐cement models of thin‐walled shallow RC shells, are discussed. Behaviour of the tested models is compared with that of the above‐mentioned real shells and similar structures, which also collapsed. The critical buckling loads for the shells are obtained. It is shown that these loads are lower than the actual ones; thus, the shells buckling was unavoidable. To prevent brittle shell failure, they should be designed using other dominant failure modes that appear before the buckling. Possible failure schemes of real RC shells can be predicted using dominant failure modes obtained by laboratory testing of scaled models. Copyright © 2012 John Wiley & Sons, Ltd.     

Quantitative study of the effect of electromagnetic field on scale deposition on nanofiltration membranes via UTDR

Ultrasonic time-domain reflectometry (UTDR) as an in situ, non-invasive real-time technique has been successfully utilized to quantify membrane fouling and cleaning. This study describes an existing ultrasonic technique for quantitative study of the effect of magnetic fields on CaCO₃ scale deposition on the membrane surface during crossflow nanofiltration (NF). The fouling experiments were conducted with CaCO₃ solution containing Ca²⁺ of 1.8 and 3 mmol/L. The experimental electromagnetic field (EMF) was 0.02 T. A commercial NF membrane and a highly sensitive ultrasonic sensor were used in all the experiments. Results show a good relationship between the ultrasonic measurements and the development of CaCO₃ scale on the NF membrane surface. An increase in the amplitude of differential signal with operation time results from the deposition of the CaCO₃ scale layer. In addition, the movement of the differential signal in the time domain observed is associated with an increase in the thickness of the fouling layer. The UTDR technique is capable of measuring the rate of fouling layer formation under different treatment conditions, i.e. with non-magnetic field (NMF) and EMF. Scale layer of deposited CaCO₃ obtained in the experiment with NMF is denser and thicker than that with EMF. The scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses imply that the magnetic treatment suppresses the formation of calcite crystals and prefers vaterite and aragonite. Furthermore, the ultrasonic technique is sensitive to the different fouling rate between experiments carried out with 1.8 and 3 mmol/L CaCO₃ solutions. The thickness of the fouling layer measured by weight measurement is consistent with that obtained by UTDR in real time. The thinner and less dense scale layer is the main reason for the slower flux decline. Overall, independent measurements such as the flux-decline data, SEM analysis and weight measurement corroborate the ultrasonic measurements.     

3S技术在日本筑波山梅林公园规划上的应用

以日本筑波山梅林公园规划为例,总结了利用3S技术进行园林规划的方法及其起到的作用,并阐明了如何将得到的经验教训结合我国国情,推动我国相关方面的发展进程.     

Fast accessing Web3D contents using lightweight progressive meshes

Accessing Web3D contents is relatively slow through Internet under limited bandwidth. Preprocessing of 3D models can certainly alleviate the problem, such as 3D compression and progressive meshes (PM). But none of them considers the similarity between components of a 3D model, so that we could take advantage of this to further improve the efficiency. This paper proposes a similarity‐aware data reduction method together with PM, called lightweight progressive meshes (LPM). LPM aims to excavate similar components in a 3D model, generates PM representation of each component left after removing redundant components, and organizes all the processed data using a structure called lightweight scene graph. The proposed LPM possesses four significant advantages. First, it can minimize the file size of 3D model dramatically without almost any precision loss. Because of this, minimal data is delivered. Second, PM enables the delivery to be progressive, so called streaming. Third, when rendering at client side, due to lightweight scene graph, decompression is not necessary and instanced rendering is fully exerted. Fourth, it is extremely efficient and effective under very limited bandwidth, especially when delivering large 3D scenes. Performance on real data justifies the effectiveness of our LPM, which improves the state‐of‐the‐art in accessing Web3D contents. Copyright © 2015 John Wiley & Sons, Ltd.     

Social context cognition crowd‐sourcing and semi‐automatic parametrization

This paper presents a semi‐automatic method of parameterizing an existing social context cognition model. It discusses benefits of the social context cognition models for example in personality modeling and their key issue that is parametrization. It briefly introduces social context cognition model and describes a new method of its crowd‐sourcing‐based parametrization. Later, validation is provided, and ability to recreate social context cognition in the provided samples is presented with good generalization for the unknown cases. Finally, model's stability for the continuous stream of dynamic social context input data is shown. Presented system contributes to the believable agent modeling and social simulations by making much needed applications of social context cognition models easier by addressing the so far unsolved troublesome parametrization issues. Copyright © 2016 John Wiley & Sons, Ltd.     

Er_2O_3改性尼龙6的制备及性能研究

用熔融纺丝法成功制备了PA6/PP-g-MAH/Er2O3纤维材料,采用DSC、FTIR研究Er2O3对尼龙6的结构性能影响,通过检测混合样品的熔融指数、拉伸强度和断裂伸长率研究Er2O3对尼龙6的力学性能影响。结果表明:当Er2O3的添加量为4 phr时,PA6/PP-g-MAH/Er2O3初生纤维强度提高了51%,断裂伸长率增加了10.6%,同时结晶温度降低,熔融温度降低,熔体流动速率提高。     

2,3-吡啶二甲酸的合成

采用喹啉为原料,以高锰酸钾为氧化剂,以水为溶剂,经过氧化、浓缩、浓盐酸酸化、抽滤、干燥,合成了2,3-吡啶二甲酸,产率43.7%。