Papers by Keyword: Clay

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Authors: Qing Chun Yang
Abstract: Safety assessment of nuclear waste disposal in a deep geological repository requires understanding and quantifying radionuclide transport through the hosting geological formation. Radionuclide diffusion is the main transport mechanism in clay formations since they usually have small hydraulic conductivities. Thus, understanding diffusion and determining diffusion parameters under real conditions is crucial for the performance assessment of a deep geological repository. In this paper, a comparative analysis is performed which focus on the dimensions of the packed-off section where tracers are injected and the packer between the intervals, diffusion of neutral (HTO), anionic (I) and sorbing cationic tracers with different distribution coefficients (22Na and 85Sr) has been simulated considering the anisotropy effect. The results indicate that The expected anisotropy has been clearly measurable for the sake of a short injection interval, in the final geometric configuration, the length of injection interval is larger than the transport distance, so the anisotropy effect is not as clearly measurable as in the preliminary because practically no tracer breakthrough from one interval to the other is expected if diffusion anisotropy is confirmed. The tracer depletion in the final design is larger than in the preliminary design.
1434
Authors: Jia Qing Du, Shou Ji Du, Zhi Wang
Abstract: With the oil and gas exploitation develop to the deep sea; offshore platform under extreme environment load needs more stable anchorage foundation. Based on the slender suction anchor of SPAR, three-dimensional numerical analysis method was presented to study the ultimate pull-out capacity. Based on the geological conditions from South China Sea, clay and sand was selected as soil conditions to make a comparison analysis. The effects of soil type, load positions, load angles and aspect ratio on the ultimate bearing pull-out resistance of the suction foundation were studied. The comparison analysis results indicated that the ultimate pull-out resistance of suction anchors in sand has a greater rise rate and achieve ultimate pull-out capacity need smaller displacement than in clay; load point and load angles have a great impact on the resistance and there is a critical aspect ratio under inclined loading in sand.
613
Authors: Shi Chun Mu, M. Pan, Run Zhang Yuan
Abstract: Some minerals were considered to store hydrogen on the basis of their porous crystal structure. Besides of crystal graphite and zeolite, some natural clay minerals such as palygorskite-sepiolite minerals with nano-scale channels and polar surface can also store hydrogen. The hydrogen storage mechanism of porous minerals was discussed. The experimental results showed a potential application of palygorskite-sepiolite minerals as the media of hydrogen storage.
2441
Authors: Xiao Dong Tian, Bo Xuan Wei, Wei Ping Hu
Abstract: Stop-motion animation is an ancient form of animation. After nearly a century of development, the material application of stop-motion animation becomes diversified. Currently, however, the well-known stop-motion animations are produced by clay materials. Clay materials play an important role in the application of stop-motion animation. Clay materials, because of its expressive ability demonstrated by its strong plasticity, enables the roles it has shaped lively and characteristic and the stop-motion animation to be full of affinity and vitality. This paper starts from the properties and material expressive ability of clay materials, combined with the short clay animation film named Daffodil to have a study and analysis of the vitality demonstrated by clay materials.
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Authors: Wei Xin Hu
Abstract: A new environment-friendly wall material- the unfired brick is produced by using clay, carbide slag, fly ash and cement as the main raw materials,and certain amount of chemical excitator. The primary mixing ratio is designed on the basis of its mechanical properties and durability. When adopting water curing under normal temperature and atmosphere pressure,the compressive strength,flexural strength and frost resistance of the unfired brick are measured. The results reveal that the optimum mixing ratio for unfired brick is: Carbide slag 30%,fly ash 30%,cement 25% and clay 15%. For the unfired brick formed by vibration with the optimum mixing ratio,the min. compressive strength of each brick is more than 10 MPa, the overall properties meet the requirement as specified in standard JC 239—2001“Fly Ash Brick”.
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Authors: Sérgio Neves Monteiro, Carlos Maurício Fontes Vieira
Abstract: Clay based ceramic is one of the most used materials in the form of construction blocks, bricks and tiles. Sintering of clay powders is recommended to be carried out above 900°C to benefit from fluxing phase consolidation. However, solid state consolidation of clay bodies made with mixture of powders may occur bellow this temperature by surface diffusion within the nanopores of the layered silicate particles. The objective of this work was to characterize the activation energy for the sintering of plastic clay at temperatures bellow 900°C. Cylindrical samples of sintered kaolinitic clay powders were tested by diametrical compression at 500, 600, 700 and 800°C in the time interval from 5 minutes to 50 hours. The results showed that the value found for the activation energy could be related to the diffusion of the mineral species that compose the clay. Moreover, this activation value corroborates the efficiency of lower sintering temperature for practical fabrication of clay based ceramics.
813
Authors: I.O. Ogunleye
Abstract: The thermo-physical properties of some varieties of sawdust and some additives are presented. They are thermal conductivity, heat capacity and specific gravity. The methods of investigation used are Lee’s Disc Apparatus, heat balance and gravimetric method respectively. The sawdust specimens were obtained from six varieties of wood. The additives employed on two typical sawdust samples are cement and silica clay. The values of thermal conductivity range between 0.440 and 0.204 W/m K, and heat capacity between 58,644.08 and 29,584 J/kg K. The highest specific gravity is 0.256 and the least value is 0.107. It was observed that as the clay content increases, specific gravity and the thermal conductivity also increases while the specific heat capacity decreases.
752
Authors: Djamil Benghida
Abstract: Durable, renewable, and affordable are the three characteristics of the adobe brick, one of the widely used construction material in human civilization, but is always neglected. Traditionally, price has been the foremost consideration when comparing similar materials or materials designated for the same function. That is why by the post-war period, the concrete was adopted as a universal building material in response of the massive housing demand. The intergovernmental concerns never took into consideration both the sustainability factor and the cultural one, not until the 1990s when research on climate change expanded and the sustainable development took an important place in the different academic cross fields: engineering, biology, technology and architecture. The main focus by then was the reduction the CO2 gas emissions emitted by the building sector which is now approximately 30% of the global energy-related. Researchers are focusing on creating a completely new green eco-material an alternative to the concrete, but in this paper, I will demonstrate why is it worth to reinvigorate centuries-old eco-construction material. Adobe bricks are currently the best choice to built affordable housings in response to the chronicle demand. Not only they have a track record that makes their thermal mass performance easier to evaluate, but also they can last 400 years or more when properly maintained. Comparatively, new technologies require testing over time to determine their long-range effectiveness.
386
Authors: Hai Hui Bai, Ran Jin, Qing Song Zhang, Guo Zheng, Di Guo
Abstract: In this study, different appearances, structures and morphologies of macro-clay G105-Polymer grade montmorillonite (PMMT) and nanoclay Lithium magnesium silicate (LMSH) were compared and analyzed, which were used in different conditions of non-adsorption and adsorption of crystal violent (CV). Adsorption kinetics and properties of the macro/nanoclay in CV solution were studied, and adsorption time, dye concentration and environmental pH were the main factors on the inspection in this work. The adsorption mechanisms of the macro-/nanoclay on CV were investigated. The results showed that adsorption actions of PMMT and LMSH on CV were some similar, such as time-dependent, linear growth of adsorbed CV amount with increasing CV concentration, adsorption capacity of macro-/nanoclay declined firstly and then increased in 10mg/L CV solution along with increasing pH value. But the adsorption differences in two systems of PMMT-CV and LMSH-CV were obvious. Adsorption behavior of LMSH-CV system showed two adsorption phenomena. Under neutral conditions, adsorbed CV amount in 0.5g LMSH was 1.69 times that of PMMT. Adsorption amount of LMSH was more significant to be affected by dye concentration and pH conditions. The research achievements further showed that adsorption mechanism was the root cause of the following difference. The adsorption of PMMT-CV relied mainly on iron-exchange effect of layers replaceable cations and surface adsorbed ions with CV cations, while the significant adsorption of LMSH-CV was mainly due to the electrostatic interaction from layers negative charge distribution and CV cationic properties in the solution, partly surface ions exchanges also existed in the adsorption process of LMSH-CV.
488
Authors: Jiří Teslík, Naďa Zdražilová, Martina Vodičková
Abstract: With regard to the current European trends in civil engineering and sustainability are still explored new building materials. In this case it is ideal to use natural materials such as straw. Its use as a building material is both ecological and economical. Excellent thermal insulation properties of straw have been known for centuries but the aim of this paper and the measurements were also demonstrate air-tightness and acoustic properties of a straw houses in the Czech Republic.
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