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991.
The performance of a desiccant wheel is evaluated by modelling a representative channel. The hypothesis of negligible resistances to heat and mass transfer in the cross-direction is assumed in the thin porous desiccant wall of the channels and the airflow is treated as a bulk flow. Parametric studies were conducted to investigate the influence of the atmospheric pressure decrease from 101,325 Pa to 60,000 Pa (0-4217 m of altitude) on the mass transfer rate of desiccant wheels considering distinct channel lengths and different inlet airflow rates, a large range of values of the rotation speed, as well as three alternative ways to specify the inlet conditions of the regeneration and of the process airflows. A procedure to derive correlations based on the numerical results is presented for the correction factor of the mass transfer rate when a desiccant wheel is operating at non-standard atmospheric conditions. Four parametric studies were performed, the derived correlations were tested and a good agreement was found between the estimated correction factor and the correction factor calculated after the numerical results. 相似文献
992.
Bistable asymmetric composites with piezoelectric actuators that induce ‘snap-through’ from one stable state to another are candidate smart materials for shape-change (morphing) applications. This paper combines a homogenised piezoelectric model of a Macro Fibre Composite with a bistable asymmetric laminate model. Both predicted shape and snap-through voltage of a piezo-actuated [0/90]T laminate compare favourably with experimental results. 相似文献
993.
The present study analyses an aircraft composite fuselage structure manufactured by the Liquid Resin Infusion (LRI) process and subjected to a compressive load. LRI is based on the moulding of high performance composite parts by infusing liquid resin on dry fibres instead of prepreg fabrics or Resin Transfer Moulding (RTM). Actual industrial projects face composite integrated structure issues as a number of structures (stiffeners, …) are more and more integrated onto the skins of aircraft fuselage. A representative panel of a composite fuselage to be tested in buckling is studied numerically. 相似文献
994.
Multi-walled carbon nanotube (MWCNT)-filled silicone rubber (SR) composites were prepared by solvent evaporation method, with different MWCNT concentrations from 0.5 wt% to 6.5 wt%. Alternating current (AC) electrical properties of samples with interdigital electrodes were measured in the frequency range from 20 Hz to 1 MHz. Impedance spectroscopy analysis reveals a frequency-independent percolation transition between 2.0 wt% and 2.9 wt%. Samples above the percolation threshold exhibit more regular variations: the magnitude of impedance decreases gradually with frequency in the low-frequency range, and then decreases as a power law beyond a critical frequency, with the exponent in a limited range indicating the AC universality of disordered solids; the plots of real and imaginary parts of impedance fit semicircles well in the complex plane, implying semiconductive behaviours. Over the concentration range tested, a multi-stage circuit model consisting of resistor–capacitor (RC) networks is proposed to simulate the electrical responses of samples. The validity of the modelling approach is verified by comparing simulation results to experimental results, and is further supported by the analysis of the characteristic frequency. The use of equivalent circuits in modelling provides a further insight into the conducting network inside nanocomposites and more valuable guidance for the design of correlative devices. 相似文献
995.
Fuel gas production from biomass using circulating fluidised bed technology is presented in our laboratory. This improved technical concept is aiming at producing high quality gas, in terms of low tar level and particulates carried out in the fuel gas, and overall emissions’ reduction associated with fuel gas combustion, as well as stable and reliable operation with the minimum fluctuations in the producer gas volume and composition. Based on this concept, a characteristic theoretical modelling approach involving hydrodynamics, chemical reaction kinetics, and energy balance is accordingly discussed. In addition, very preliminary experimental results from a laboratory-made test rig are also given. 相似文献
996.
Lei Wu Xiao-yi Ma Hui-ling Peng Jing Wang Jia-xing Wen 《The International journal of environmental studies》2013,70(4):637-654
The presence of pesticides via non-point source (NPS) pollution might be a threat to human health and aquatic ecosystems. This study aims to characterize quantitatively the distribution and transport of Linuron in a coupled canopy-soil system by using modelling techniques, viz. an integrated pesticide transport modelling system to simulate three-phase pesticide fate and transport in a tomato field of the Three Gorges Reservoir area. Results indicate that spatio-temporal distributions of Linuron levels in surface soil are dominated by its properties, rainfall, irrigation and its applications. The occurrence and distribution of Linuron in subsurface and deep soil are closely related to the cumulative and delayed effects. Runoff and erosion also play important roles in the environmental transport and fate of Linuron. The results may be useful for taking effective pesticide management measures to control pesticide NPS pollution at watershed scales. 相似文献
997.
Neuzil J Cerny J Dyason JC Dong LF Ralph SJ 《Molecular nutrition & food research》2011,55(10):1543-1551
Scope: Vitamin E (VE) analogues, epitomised by the prototypic α‐tocopheryl succinate (α‐TOS), are potent anti‐cancer agents. α‐TOS has recently been shown to trigger apoptosis by targeting the ubiquinone (UbQ) binding site(s) of the mitochondrial complex II (CII) and to cause excessive production of reactive oxygen species. Methods and results: We have modelled, using two approaches, a range of VE analogues into the proximal UbQ (Qp) binding site of CII. This study reveals that in both cases, the calculated interaction energies of individual VE analogues correlate (R2 value >0.8) with their toxicity to cancer cells. Conclusion: These data further support the UbQ site(s) of CII as an important target determining the anti‐cancer activity of VE analogues as well as other emerging anti‐cancer drugs. 相似文献
998.
Ka-Leung Lam Adetoyese O. Oyedun Kwok-Yuen Cheung King-Lung Lee Chi-Wai Hui 《Chemical engineering science》2011,(24):6505
In literature, the reaction kinetic of pyrolysis process is often determined and modelled under constant heating rates. In reality, the heating rate of an industrial pyrolysis process is difficult or often not necessary to be kept constant. The variation of heating rate at different reaction stages, termed “dynamic heating”, governs the pyrolysis performance such as production rate, energy consumption, product quality, etc. In this work, pyrolysis progress with dynamic heating is being studied. The rate and reaction heat of tyre pyrolysis at different heating rates are obtained experimentally. A transient model considering the effect of dynamic heating was then developed and compared with the conventional static heating model. Results show that a higher heating rate favours the production of volatiles and shifts the overall pyrolysis heat flow to more endothermic. The significance of the dynamic heating model was observed for processes with large feed size and/or with high heating rate. 相似文献
999.
A. Shrivastava 《Powder Technology》2011,211(1):46-53
Production of ultrafine particles by grinding in attritor mill has been successfully applied in chemical, pharmaceutical and mineral processing industries. It has also been demonstrated as a cost effective and efficient method for production of nanoparticles. The present study attempts to relate the effects of operating variables on the Rosin Rammler equation parameter (Xd), which is indicative of the size of product. Operating parameters considered for the investigation are initial size of particles, ball loading, slurry mass fraction, diameter of grinding media, pin tip velocity and ratio of Young's modulus. The results indicate that the ratio of Young's modulus and initial size of particles have significant effects; ball loading, diameter of grinding media and pin tip velocity have moderate effects; and slurry mass fraction does not have a significant effect on the final size of the powder. The paper illustrates how statistical analysis, when appropriately applied, can be used to analyze complex unit operations such as the attritor mill and can be effective in gathering of process understanding. 相似文献
1000.