Enablers and barriers of the multi-user virtual environment for exploratory creativity in architectural design collaboration

Pioneering psychology and co-design research has highlighted the potential that multi-user virtual environment (MUVE) may help architects’ exploratory creativity that is a recursive search to discover an optimal match of novel and appropriate solutions. However, it has been not reported hitherto in what ways MUVE helps or obstructs architects’ exploratory creativity in individual and collaborative modes of collaboration. To investigate this issue, we compared MUVE and sketching media in face-to-face and remote collaboration modes, involving 22 pairs of architecture major students. Based on interview and video-observation, we discovered that (1) in MUVE, anthropomorphic avatars, which other media do not have, enabled individual and collaborative explorations to discover unexpected affordances of new solutions, with evaluation on physical properties and layouts of solutions. In addition, (2) co-presence with collaborator’s avatars enabled inspiration on new ways of problem-solving and puzzle-making through shared design processes and events, with co-evaluation on social aspects of design solutions. (3) Co-presence in a shared environment also allowed mutual co-exploration that promotes emerging creative solutions, with co-modification on design errors. As barriers of MUVE, (4) avatar’s immersion caused inconvenient perception to explore large-scaled environments and track collaborators’ different experiences, but the barriers were not reported in remote collaboration.     

Synthesis of barium strontium titanate quasi photonic crystals with nanopore arrays by sol–gel technique

We report on the synthesis, characterization and optical properties of barium strontium titanate (BST) quasi photonic crystals (PCs) through a sol–gel technique with the porous alumina template (PAT). The structure, morphology and pore-size distribution of the samples were characterized by SEM, XRD and EDS, The Ba_0.6Sr_0.4TiO₃ PCs of crystalline cubic phase with uniform pore size and ordered arrange were successfully synthesized. The obtained quasi BST PCs not only show that the nanostructure has spatially periodical orderly arrangement, but also exhibit good optical transmittance properties. The advantage of this sol–gel technique with PAT to fabricate ferroelectric (FE) nanopore arrays lies in its low cost and simplicity. This study opens a pathway for the effective fabrication and studies of FE nanopore arrays in uniquely large area.     

Ink drop filling by a slot coating die for an electrowetting display panel

Ink drops have to be filled into the square cells for an electrowetting display panel. Several ink solutions such as dodecane, tetradecane, and hexadecane were used as test liquids. These fluids have viscosities less than 4 mPas and surface tensions between 23.3 and 26 mN/m and contact angles less than 50°. A slot coating die was employed to deliver these liquids to fill up the square cells. The effects of several parameters such as coating thickness and coating speed were examined. Operating windows inside which the stable filling is possible could be found for these liquids. Several defects were observed outside the operating windows. A flow visualization technique was applied to observe the fluid motion in the coating bead region, particularly the movements of upstream and downstream menisci, the mechanism of liquid filling was discussed.     

基于房屋建筑工程中外墙防渗漏施工研究

做好房屋外墙抗渗漏设计与施工是提升建筑行业整体施工技术水平的重要举措。本文分析了房屋建筑工程外墙渗漏的原因，并针对这几个原因，探讨了如何做好抗渗漏施工的举措，希望能为房屋外墙抗渗漏施工提供参考。     

Hydrogen permeation in high strength steel under load in aqueous environment

Abstract

The hydrogen assisted cracking problem is one of the major causes of the failure occurring in the high strength steel structures used in various industries. In aqueous environment, hydrogen is generated by the hydrogen reduction reaction on the steel surface. With depletion of the high quality resources in oil and gas industry, the hydrogen assisted cracking problem becomes severe in sour environment, which contains high amount of H₂S. Understanding on the hydrogen permeation behaviour is crucial to deal properly with the hydrogen related problems since they are primarily determined by the hydrogen uptake and transport in the steel. The Devanathan–Stachurski method is widely used to evaluate electrochemically the hydrogen permeation behaviour. This method has been successfully used for the steel with no load. Under loading condition, this electrochemical test method has been modified to accommodate the externally applied load. However, the data require careful examination to validate the technical importance because of the stability and homogeneity of palladium layer coated on the steel surface under load. In this paper, the hydrogen permeation test method under loading condition will be reviewed for the high strength steels used in oil and gas industry. The factors affecting the hydrogen permeation in the high strength steel will be discussed in terms of the applied stress level and the sulphide film forming on the steel surface in sour environment.     

谈保证外墙外保温施工质量的技术措施

针对外墙外保温技术施工过程中经常会遇到保温板粘结不牢固、板缝渗漏、热桥部位处理不到位等质量问题,结合GB 50411-2007建筑节能工程施工质量验收规范的相关要求,探讨了保证外墙外保温施工质量的施工技术措施,从设计、材料、施工三方面入手,阐述了具体的质量保证措施,以期指导实践。     

Simulation on thermoelectric device with hydrogen catalytic combustion

The micro-thermoelectric-generator based on catalytic combustion of hydrogen and oxygen was designed. With the application of general finite reaction rate model in CFD software of FLUENT, the effect of inlet parameters on the highest temperature difference between the hot and cold plate of the generator was studied. Results showed that, the temperature in the heating and cooling channel of the micro-thermoelectric-generator was uniform; with the increasing of inlet reactant temperature, the highest temperature difference increased, but the total efficiency of the generator decreased. Results can be used to the further design and optimization of micro-thermoelectric-generator based on hydrogen catalytic combustion.     

Determination of the best behavior among AISI D3 steel, 304 stainless steel and CrN/AlN coatings under erosive-corrosive effect

The erosive-corrosive effect of aqueous NaCl slurries on metals and metals coated with a multilayer system was analyzed. The erosion-corrosion experiments were performed in a test machine in which the impingement velocity, impact angle, concentration of solids and pH of the solution were controlled. Polarization curves were simultaneously obtained to correlate the electrochemical effects to the erosive wear mechanisms. The slurry used consists of silica particles suspended in a mixture of acid solution and 3.5% NaCl, with a pH value of 5.6. Electrochemical results showed the best corrosion resistance for steel coated with CrN/AlN system deposited with 50 bilayer. Additionally, the surface analysis by SEM micrograph revealed formation of cracks in CrN/AlN multilayers coating and plastic deformation in both steel substrates (AISI D3 steel and 304 stainless steel), especially when the mean impact angle is a critical value of 90°. Measurements of critical and passive current densities showed that the behavior of coated materials differed depending on the substrate that is used. Nonetheless, in a general way, by increasing the impact angle and by changing its incidence from normal to grazing, it led to an improved resistance to erosion-corrosion processes.     

Enhancement of pentlandite surface magnetism and implications for its separation from serpentine via magnetic separation

The magnetism of pentlandite surface was enhanced through the selective precipitation of micro-fine magnetite fractions on pentlandite surfaces. This was achieved through adjustment of slurry pH and addition of surfactants. The results showed that at pH 8.8 with the addition of 100 g/t sodium hexametaphosphate, 4.5 L/t oleic acid, and 4.5 L/t kerosene, significant amount of fine magnetite particles adhered to the pentlandite surface, while trace amount of coating was found on serpentine surfaces. Thus, the magnetism of pentlandite was enhanced and pentlandite was well separated from serpentine by magnetic separation under the magnetic field intensity of 200 kA/m. Scanning electron microscopy (SEM) and zeta potential measurement were performed to characterize changes of mineral surface properties. Calculations of the extended Derjaguin–Landau–Verwey–Ocerbeek (EDLVO) theory indicated that, in the presence of surfactants the total interaction energy between magnetite and pentlandite became stronger than that between magnetite and serpentine. This enabled the selective adhesion of magnetite particles to pentlandite surfaces, thereby enhancing its magnetism.     

Impacts of zinc layer and pouring method on interface performance for Al-22Si/ZL104 bi-metal

Bi-metal material consisting of spray-formed Al-22Si and ZL104 is a suitable candidate for applications in internal combustion engines. This research investigated the effects of surface treatment and appropriate gating system on the microstructures and mechanical properties in evaluating the optimal strategy for producing high quality bi-metal materials. The bi-metal materials were prepared using ZL104 gravity casting by different pouring types around the spray-formed Al-22Si with varied surface treatments. The wettability between Al-22Si and ZL104 was significantly improved when Zn coating was used to remove the natural oxide layer. This research also obtained the improved interfacial microstructures and interfacial bonding strength for materials when applying the appropriate pouring method. The hardness profiles of Al-22Si/ZL104 bi-metal were consistent with the observed microstructures. The average tensile strength of the bi-metal material with zinc coating is ~42.3 MPa, which is much higher than that with oxide film at ~10 MPa. The process presented is a promising and effective approach for developing materials in the automotive industry.