The isomerization of endo-tetrahydrodicyclopentadiene (THDCPD) to exo-THDCPD over AlCl3 catalyst has been studied in a batch reactor. The effects of temperature, catalyst loading, and the type and amount of solvent on...
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The heat transfer enhancement of Longitudinal Vortex (LV) is a kind of technology with efficiency is high and resistance is low. The effective influence distance of LV is very important to extend this kind of technolo...
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The adhesion, activation and aggregation of platelets play an important role in the primary thrombus formation. In present paper, platelets, plasma, normal and injured endodermis of the vessel are modeled as particles...
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The adhesion, activation and aggregation of platelets play an important role in the primary thrombus formation. In present paper, platelets, plasma, normal and injured endodermis of the vessel are modeled as particles with different characteristics and simulated by the Moving Particle Semi-implicit (MPS) method. In order to simulate the aggregation and adhesion of platelets on the injured endodermis of the vessel, a mechanical adhesion force model is introduced according to the inter-molecular force and physiological interaction between platelets and endodermis is modeled by the stretch and rotation of a spring. By this method, the formation of primary thrombus at the injured endodermis of horizontal and bending vessel is numerically reproduced. Results show that the thrombus forms quickly and the number of adhered platelets will not increase if thrombus has been formed. Through the analysis of flow field, the platelets go through the vibration, steady and potential break free process. Compared with horizontal vessel, the thrombus formation at the bending vessel is slower.
The performance of 3 types of energy utilization cycles including the organic Rankine cycle, the single stage static hydrogen compression cycle, and the new multistage continuous hydrogen compression cycle were analyz...
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Since the opacifier-loaded silica aerogel composites have strong ability to inhibit radiant heat transfer compared to the pure silica aerogel, they can improve effectively the insulation performance at high temperatur...
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Since the opacifier-loaded silica aerogel composites have strong ability to inhibit radiant heat transfer compared to the pure silica aerogel, they can improve effectively the insulation performance at high temperature conditions and have been used extensively as thermal insulation materials in a variety of industrial applications. This paper developed a theoretical model to predict the radiant performance of opacifiers by using the Mie scattering theory, Beer law and a radiant heat transfer equations. The model was used to calculate the radiant performance of carbon black opacifier with various particle diameters and the radiant performance of three opacifiers, carbon black, SiC and ZrO2. The results showed that the opacifier-loaded silica aerogel composites had much higher extinction coefficient than the pure silica aerogel in a range of 3-7.5 μm wave band or in medium and high temperature ranges, which significantly improved the insulation performance of composites. With a fixed opacifier mass fraction, the optimal particle diameter was 2-3 μm for carbon black opacifier. Among the three opacifiers, carbon black opacifier had better opaque property than that of SiC and ZrO2 opacifiers. Due to poor thermostability for carbon black opacifier at high temperature conditions, the optimal material design for opacifier-loaded silica aerogel composites should be as follows: SiC or ZrO2 are added on high temperature side of aerogel and carbon black is added on low temperature side.
A series of SAPO-34 molecular sieves with different SiO_(2)/Al_(2)O_(3)ratios have been synthesized for the methanol-to-olefin(MTO)*** physico-chemical properties are characterized by various techniques such as X-ray ...
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A series of SAPO-34 molecular sieves with different SiO_(2)/Al_(2)O_(3)ratios have been synthesized for the methanol-to-olefin(MTO)*** physico-chemical properties are characterized by various techniques such as X-ray diffraction(XRD),scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS),Fourier transform infrared spectroscopy(FT-IR)and N2 *** results are compared with those of the commercial HZSM-5,which show that the crystallinity and particle diameter of SAPO-34 as well as HZSM-5 increase with SiO_(2)/Al_(2)O_(3)*** variation of BET surface area of SAPO-34 is different from that of HZSM-5 and the sample with SiO_(2)/Al_(2)O_(3)ratio of 0.4 exhibits the highest BET surface ***-IR spectra indicate that HZSM-5 has both Brǿnsted and Lewis acid sites and Brǿnsted acid sites are stronger,whereas SAPO-34 samples are dominated only by Lewis acid *** the SiO_(2)/Al_(2)O_(3)ratio increases,propylene and butylenes become the predominant product of the MTO reaction over *** contrast,the main products of this reaction catalyzed by SAPO-34 are ethylene and *** to the product distribution,the reaction mechanism over HZSM-5 catalysts is proposed.
The convective heat transfer of the cold cabinet was investigated by using two-fluid model after the effectiveness of new model was confirmed. This study includes the influence of wind speeds, wind directions and spee...
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The convective heat transfer of the cold cabinet was investigated by using two-fluid model after the effectiveness of new model was confirmed. This study includes the influence of wind speeds, wind directions and speeds of air curtain. The results show that the convective heat transfer is improved along with increasing of the wind speed. In a relatively short time, there is a linear relationship between convective heat transfer and time. The wind direction has small effect on heat transfer when it is less than about 15° while has appreciable impact and made an increase of energy consumption by approximately 30% when it reaches 30°. The air curtain, a major constituent of the refrigeration system of cold cabinet, provides a barrier of moving air across a door opening and reduces heat transfer by preventing the penetration of hot air. The simulation shows that there is the minimum speed and the best speed range of air curtain. The air curtain can not be formed when the speed is less than 1.5 m·s-1, while has a large spillover of cold air when it is greater than 3.0 m·s-1. From the above, the best speed of air curtain ranges from 2.6 m·s-1 to 3.0 m·s-1.
A 40-60 t/h modularized dry coal beneficiation process with a novel method to control the bed was designed around a gas-solid fluidized bed separator. Furthermore, the hydrodynamics of medium-solids consisting of wide...
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A 40-60 t/h modularized dry coal beneficiation process with a novel method to control the bed was designed around a gas-solid fluidized bed separator. Furthermore, the hydrodynamics of medium-solids consisting of wide-size-range magnetite powder (0.3-0.06 ram) and 〈1 mm fine coal were numerically studied. The simulation results show that the fluidization performance of the wide-size-range medium-solid bed is good. The separation performance of the modularized system was then investigated in detail using a mixture of 〈0.3 mm magnetite powder (mass fraction of 0.3-0.06 mm particles is 91.38 %) and 〈1 mm fine coal as solid media. The experimental results show that at separation densities of 1.33 g/cm^3 or 1.61 g/cm^3, 50-6 mm coal can be separated effectively with probable error, E, values of 0.05 g/cm^3 and 0.06 g/cm^3, respectively. This technique is beneficial for saving water resources and for the clean utilization of coal.
Molecular dynamic simulation is used to study the microstructure of four kinds of ionic liquids(ILs),[Emim]PF6,[Emim][Tf2N],[PC6,6,6,14]PF6 and [PC6,6,6,14][Tf2N] in the capture process of *** distribution function(RD...
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Molecular dynamic simulation is used to study the microstructure of four kinds of ionic liquids(ILs),[Emim]PF6,[Emim][Tf2N],[PC6,6,6,14]PF6 and [PC6,6,6,14][Tf2N] in the capture process of *** distribution function(RDF) and spatial distribution function(SDF) are used to analyze the microscopic properties of these *** calculated results show that the space distribution of CO2 around ILs determines the capability of ionic liquids for capturing *** on the analysis of SDF,CO2 and PF6-are overlapped partially around [Emim]+ in [Emim]PF6-CO2 *** the anion is [Tf2N]-,cations are mainly distributed on one side of [Tf2N]-near N atom,and CO2 is concentrated on two sides near the fluoroalkylgroup(?CF3),and there is little overlapped district between cation and *** [PC6,6,6,14]PF6-CO2 mixture,layered structure is found and CO2 is much nearer to PF6-than [PC6,6,6,14]+.Based on the analysis of RDF,in the phosphonium-based ILs,the highest distribution densities of anions and CO2 around cations are about 6 and 3 times as their average ones respectively,while in the imidazolium-based ILs,they are about 3 and 2 respectively,this means that the distributions of CO2 and anions around the imidazolium-based ILs are more evenly distributed than those around the phosphonium-based ILs.
Thermal conductivity of Ar-Cu nanofluid confined between two parallel walls (in a nanochannel) is calculated by equilibrium-molecular-dynamics (EMD) simulation through Green-Kubo formula. The results show that the vib...
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