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Efficient acetylene/carbon dioxide separation with excellent dynamic capacity and low regeneration energy

《化学科学与工程前沿(英文)》   页码 1616-1622 doi: 10.1007/s11705-022-2183-x

摘要: Adsorptive separation of acetylene/carbon dioxide mixtures by porous materials is an important and challenging task due to their similar sizes and physical properties. Here, remarkable acetylene/carbon dioxide separation featuring a high dynamic breakthrough capacity for acetylene (4.3 mmol·g–1) as well as an ultralow acetylene regeneration energy (29.5 kJ·mol–1) was achieved with the novel TiF62–-pillared material ZU-100 (TIFSIX-bpy-Ni). Construction of a pore structure with abundant TiF62– anion sites and pores with appropriate sizes enabled formation of acetylene clusters through hydrogen bonds and intermolecular interactions, which afforded a high acetylene capacity (8.3 mmol·g–1) and high acetylene/carbon dioxide uptake ratio (1.9) at 298 K and 1 bar. Moreover, the NbO52– anion-pillared material ZU-61 investigated for separation of acetylene/carbon dioxide. In addition, breakthrough experiments were also conducted to further confirm the excellent dynamic acetylene/carbon dioxide separation performance of ZU-100.

关键词: adsorption     acetylene/carbon dioxide separation     dynamic capacity     anion-pillared hybrid material    

Dynamic simulation of urban water metabolism under water environmental carrying capacity restrictions

Weihua ZENG,Bo WU,Ying CHAI

《环境科学与工程前沿(英文)》 2016年 第10卷 第1期   页码 114-128 doi: 10.1007/s11783-014-0669-6

摘要: A revised concept for urban water metabolism (UWM) is presented in this study to address the inadequacies in current research on UWM and the problems associated with the traditional urban water metabolic process. Feedback loops can be analyzed to increase the water environmental carrying capacity (WECC) of the new urban water metabolism system (UWMS) over that of a traditional UWMS. An analysis of the feedback loops of an UWMS was used to construct a system dynamics (SD) model for the system under a WECC restriction. Water metabolic processes were simulated for different scenarios using the Tongzhou District in Beijing as an example. The results for the newly developed UWM case showed that a water environment of Tongzhou District could support a population of 1.1926 × 10 , an irrigation area of 375.521 km , a livestock of 0.7732 × 10 , and an industrial value added of ¥193.14 × 10 (i.e. about US$28.285× 10 ) in 2020. A sensitivity analysis showed that the WECC could be improved to some extent by constructing new sewage treatment facilities or by expanding the current sewage treatment facilities, using reclaimed water and improving the water circulation system.

关键词: urban water metabolism system (UWMS)     system dynamic simulation     water environmental carrying capacity (WECC)     feedback loops     bilateral control    

Experimental research on dynamic operating characteristics of a novel silica gel-water adsorption chiller

WANG Dechang, WU Jingyi, WANG Ruzhu, DOU Weidong

《能源前沿(英文)》 2007年 第1卷 第3期   页码 347-351 doi: 10.1007/s11708-007-0052-4

摘要: A novel silica gel-water adsorption chiller consisting of two adsorption/desorption chambers and an evaporator with one heat-pipe working chamber is experimentally studied. The dynamic operating characteristics of the chiller and the thermodynamic characteristics of the adsorber are obtained. The experimental results show that the dynamic operating characteristics of the chiller and the thermodynamic characteristics of the adsorber are satisfactory and that the cycle is a novel and effective adsorption cycle. A mass recovery process increases the cyclic adsorption capacity of the system and improves adaptability of the chiller to a low-grade heat source. In addition, the experiment indicates that this novel chiller is highly suitable for an air conditioning system with a low dehumidification requirement or a system with a large cycle flowrate and an industrial cooling water system.

关键词: satisfactory     suitable     recovery     adsorption capacity     thermodynamic    

Application of semi-analytical finite element method to analyze the bearing capacity of asphalt pavements

Pengfei LIU, Dawei WANG, Frédéric OTTO, Markus OESER

《结构与土木工程前沿(英文)》 2018年 第12卷 第2期   页码 215-221 doi: 10.1007/s11709-017-0401-2

摘要: To facilitate long term infrastructure asset management systems, it is necessary to determine the bearing capacity of pavements. Currently it is common to conduct such measurements in a stationary manner, however the evaluation with stationary loading does not correspond to reality a tendency towards continuous and high speed measurements in recent years can be observed. The computational program SAFEM was developed with the objective of evaluating the dynamic response of asphalt under moving loads and is based on a semi-analytic element method. In this research project SAFEM is compared to commercial finite element software ABAQUS and field measurements to verify the computational accuracy. The computational accuracy of SAFEM was found to be high enough to be viable whilst boasting a computational time far shorter than ABAQUS. Thus, SAFEM appears to be a feasible approach to determine the dynamic response of pavements under dynamic loads and is a useful tool for infrastructure administrations to analyze the pavement bearing capacity.

关键词: semi-analytical finite element method     bearing capacity     asphalt pavements     moving loads     dynamic response    

Dynamic characteristics analysis of active constrained layer damping plate with various boundary conditions

Jing LU, Yu XIANG, Qiao NI

《机械工程前沿(英文)》 2011年 第6卷 第4期   页码 449-455 doi: 10.1007/s11465-011-0240-0

摘要:

Considering the direct and converse piezoelectric effect, expressions of piezoelectric membrane internal forces in the piezoelectric constrained layer were given. The control equations of the piezoelectric constrained layer and host plate were obtained in according with the thin plate theory. Based on the layer wised principle, the integrated first order differential equation of an active constrained layer damping (ACLD) plate was derived for the simply supported boundary condition. Then, this method was expanded to the ACLD plate with cantilever boundary condition by virtue of geometric analogy method. Employing the extended homogeneous capacity precision integration approach, a high precision semi-analytical method was proposed to analyze the dynamic characteristics of the ACLD plate with various boundary conditions. The comparison with the literature results has verified the accuracy and effectiveness of the present method.

关键词: active constrained layer damping (ACLD) plate     dynamic characteristics     semi-analytical method     extended homogeneous capacity precision integration approach    

Buffer capacity of granular matter to impact of spherical projectile based on discrete element method

Ying YAN, Pengfei LI, Shunying JI

《结构与土木工程前沿(英文)》 2013年 第7卷 第1期   页码 50-54 doi: 10.1007/s11709-013-0186-x

摘要: Granular matter possesses impact-absorbing property due to its energy dissipation character. To investigate the impact-absorbing capacity of granular matter, the discrete element method (DEM) is adopted to simulate the impact of a spherical projectile on to a granular bed. The dynamic responses of the projectile are obtained for both thin and thick granular bed. The penetration depth of the projectile and the first impact peak are investigated with different bed thicknesses and impact velocities. Determining a suitable bed thickness is crucial to the buffering effect of granular matter. The first impact peak is independent of bed thickness when the thickness is larger than the critical thickness.

关键词: granular matter     impact peak     buffer capacity     discrete element method     critical thickness    

Protein adsorption in two-dimensional electrochromatography packed with superporous and microporous cellulose beads

Dongmei WANG, Guodong JIA, Liang XU, Xiaoyan DONG, Yan SUN

《化学科学与工程前沿(英文)》 2009年 第3卷 第3期   页码 229-234 doi: 10.1007/s11705-009-0213-6

摘要: Anion-exchange superporous cellulose (DEAE-SC) and microporous cellulose (DEAE-MC) adsorbents were packed in an electrochromatographic column, and the effect of external electric field (eEF) on the dynamic adsorption was investigated. The column was designed to provide longitudinal, transverse or 2-dimensional (2D) eEF. It was found that the electro-kinetic effect caused by the introduction of an electric field played an important role in the dynamic adsorption of bovine serum albumin to the adsorbents. The dynamic binding capacity (DBC) in the presence of 2D eEF was higher than in the presence of a one-dimensional eEF. The effect of flow velocity on the DBC of the two adsorbents was also demonstrated. It was found that the effect of electric field on the DEAE-MC column was more remarkable than that on the DEAE-SC column at the same flow rate, whereas the DEAE-SC column showed higher DBC and adsorption efficiency (AE) than the DEAE-MC column. With increasing flow rate, the DEAE-SC column could still offer high DBC and AE in the presence of the 2D eEF. For example, a DBC of 21.4 mg/mL and an AE of 57.7% were obtained even at a flow rate as high as 900 cm/h. The results indicate that the 2D electrochromatography packed with the superporous cellulose adsorbent is promising for high-speed protein chromatography.

关键词: electrochromatography     two-dimensional electric field     dynamic binding capacity     superporous cellulose bead     protein    

Polypropylene microplastics alter the cadmium adsorption capacity on different soil solid fractions

《环境科学与工程前沿(英文)》 2022年 第16卷 第1期   页码 3-3 doi: 10.1007/s11783-021-1437-z

摘要:

Microplastics (MPs) are widely present in a variety of environmental media and have attracted more and more attention worldwide. However, the effect of MPs on the interaction between heavy metals and soil, especially in soil solid fraction level, is not well understood. In this study, batch experiments were performed to investigate the adsorption characteristics of Cd in bulk soil and three soil solid fractions (i.e. particulate organo matter (POM), organic-mineral compounds (OMC), and mineral) with or without polypropylene (PP) MPs.

关键词: Polypropylene microplastics     Cadmium     Adsorption     POM     OMC     Mineral    

Analytical algorithms of compressive bending capacity of bolted circumferential joint in metro shield

《结构与土木工程前沿(英文)》   页码 901-914 doi: 10.1007/s11709-023-0915-8

摘要: The integrity and bearing capacity of segment joints in shield tunnels are associated closely with the mechanical properties of the joints. This study focuses on the mechanical characteristics and mechanism of a bolted circumferential joint during the entire bearing process. Simplified analytical algorithms for four stress stages are established to describe the bearing behaviors of the joint under a compressive bending load. A height adjustment coefficient, α, for the outer concrete compression zone is introduced into a simplified analytical model. Factors affecting α are determined, and the degree of influence of these factors is investigated via orthogonal numerical simulations. The numerical results show that α can be specified as approximately 0.2 for most metro shield tunnels in China. Subsequently, a case study is performed to verify the rationality of the simplified theoretical analysis for the segment joint via numerical simulations and experiments. Using the proposed simplified analytical algorithms, a parametric investigation is conducted to discuss the factors affecting the ultimate compressive bending capacity of the joint. The method for optimizing the joint flexural stiffness is clarified. The results of this study can provide a theoretical basis for optimizing the design and prediciting the damage of bolted segment joints in shield tunnels.

关键词: shield tunnel     segment joint     joint structural model     failure mechanism    

A method to calculate working capacity space of multi-DOF manipulator and the application in excavating

Baochen WEI, Feng GAO

《机械工程前沿(英文)》 2012年 第7卷 第2期   页码 109-119 doi: 10.1007/s11465-012-0323-6

摘要:

Working capacity refers to the velocity output and force output of a manipulator. It is usually be represented by output capacity space. In this paper, the method of Linear Programming and a geometric method are proposed to calculate working capacity spaces in different situations. With the consideration of gravity effect of every component, the output force capacity space of heavy duty manipulators is calculated. The results show that the effect of the gravity is a translation of the capacity space. This paper gives a method for the output capacity express especially for heavy duty manipulators. The output capacity space can be helpful to the driving parameters selection. With the consideration of the gravity effect of every component and the friction at the joints, the excavating force capacity space of the heavy-load excavating mechanism is calculated and is represented as a multi-dimensional polytope. The results show that the effect of the gravity and friction is to translational act on the capacity space.

关键词: working capacity     multi-DOF manipulator     capacity polytope     excavating mechanism    

Foundations bearing capacity subjected to seepage by the kinematic approach of the limit analysis

Mehdi VEISKARAMI, Ghasem HABIBAGAHI

《结构与土木工程前沿(英文)》 2013年 第7卷 第4期   页码 446-455 doi: 10.1007/s11709-013-0227-5

摘要: An estimate of the ultimate load on foundations on soil layers subject to groundwater flow has been presented. The kinematic approach of the limit analysis was employed to find the upper-bound limit of the bearing capacity. Both smooth and rough base strip foundations were considered associated with different collapse patterns. Presence of the groundwater flow leads to a non-symmetric collapse pattern, i.e., a weak side and a strong side in two-sided collapse patterns, depending on the direction of the flow. It was found that the bearing capacity has a decreasing trend with increase in the groundwater flow gradient and hence, a reduction factor has been introduced to the third term in the bearing capacity equation as a function of the flow gradient.

关键词: foundation     bearing capacity     limit analysis     numerical computation     plasticity     seepage    

Analysis on shear capacity of prestressed concrete spatial connections

XUE Weichen, LIU Zhenyong, JIANG Dongsheng

《结构与土木工程前沿(英文)》 2008年 第2卷 第4期   页码 309-317 doi: 10.1007/s11709-008-0052-4

摘要: Based on experimental results of prestressed concrete spatial connections, nonlinear finite element models were established to analyze the shear capacity of spatial connections and parametric studies were performed using ANSYS. It is found that the shear capacity of spatial connection is influenced by joint hoop, beam prestress, column compressive load, and direction of resultant shear force. The parametric studies also indicate that the shear capacity of spatial connection under biaxial cyclic loading is lower than that of corresponding connections under plane loading. A design formula for calculating the shear capacity of spatial connections is proposed based on the parametric studies and verified by the available test results.

关键词: available     direction     nonlinear     capacity     compressive    

Undrained seismic bearing capacity of strip footing adjacent to a heterogeneous excavation

《结构与土木工程前沿(英文)》 2023年 第17卷 第4期   页码 566-583 doi: 10.1007/s11709-023-0905-x

摘要: The analysis of the bearing capacity of strip footings sited near an excavation is critical in geotechnics. In this study, the effects of the geometrical features of the excavation and the soil strength properties on the seismic bearing capacity of a strip footing resting on an excavation were evaluated using the lower and upper bounds of the finite element limit analysis method. The effects of the setback distance ratio (L/B), excavation height ratio (H/B), soil strength heterogeneity (kB/cu), and horizontal earthquake coefficient (kh) were analyzed. Design charts and tables were produced to clarify the relationship between the undrained seismic bearing capacity and the selected parameters.

关键词: excavation     finite element limit analysis     heterogeneous soil     strip footing     undrained bearing capacity    

Ultimate bearing capacity of strip footing resting on clay soil mixed with tire-derived aggregates

《结构与土木工程前沿(英文)》 2021年 第15卷 第4期   页码 1016-1024 doi: 10.1007/s11709-021-0751-7

摘要: This study investigated the use of recycled tire-derived aggregate (TDA) mixed with kaolin as a method of increasing the ultimate bearing capacity ( UBC) of a strip footing. Thirteen 1g physical modeling tests were prepared in a rigid box of 0.6 m × 0.9 m in plan and 0.6 m in height. During sample preparation, 0%, 20%, 40%, or 60% (by weight) of powdery, shredded, small-sized granular (G 1–4 mm) or large-sized granular (G 5–8 mm) TDA was mixed with the kaolin. A strip footing was then placed on the stabilized kaolin and was caused to fail under stress-controlled conditions to determine the UBC. A rigorous 3D finite element analysis was developed in Optum G-3 to determine the UBC values based on the experimental test results. The experimental results showed that, except for the 20% powdery TDA, the TDA showed an increase in the UBC of the strip footing. When kaolin mixed with 20% G (5–8 mm), the UBC showed a threefold increase over that for the unreinforced case. The test with 20% G (1–4 mm) recorded the highest subgrade modulus. It was observed that the UBC calculated using finite element modeling overestimated the experimental UBC by an average of 9%.

关键词: kaolin     physical modeling tests     stabilization     numerical modeling    

Evaluation of the power-generation capacity of wearable thermoelectric power generator

Yang YANG, Jing LIU,

《能源前沿(英文)》 2010年 第4卷 第3期   页码 346-357 doi: 10.1007/s11708-010-0112-z

摘要: Employing thermoelectric generators (TEGs) to gather heat dissipating from the human body through the skin surface is a promising way to supply electronic power to wearable and pocket electronics. The uniqueness of this method lies in its direct utilization of the temperature difference between the environment and the human body, and complete elimination of power maintenance problems. However, most of the previous investigations on thermal energy harvesters are confined to the TEG and electronic system themselves because of the low quality of human energy. We evaluate the energy generation capacity of a wearable TEG subject to various conditions based on biological heat transfer theory. Through numerical simulation and corresponding parametric studies, we find that the temperature distribution in the thermopiles affects the criterion of the voltage output, suggesting that the temperature difference in a single point can be adopted as the criterion for uniform temperature distribution. However, the criterion has to be shifted to the sum of temperature difference on each thermocouple when the temperature distribution is inconsistent. In addition, the performance of the thermal energy harvester can be easily influenced by environmental conditions, as well as the physiological state and physical characteristics of the human body. To further validate the calculation results for the wearable TEG, a series of conceptual experiments are performed on a number of typical cases. The numerical simulation provides a good overview of the electricity generation capability of the TEG, which may prove useful in the design of future thermal energy harvesters.

关键词: thermal energy harvester     thermoelectric generator     biological heat transfer     power generating capacity    

标题 作者 时间 类型 操作

Efficient acetylene/carbon dioxide separation with excellent dynamic capacity and low regeneration energy

期刊论文

Dynamic simulation of urban water metabolism under water environmental carrying capacity restrictions

Weihua ZENG,Bo WU,Ying CHAI

期刊论文

Experimental research on dynamic operating characteristics of a novel silica gel-water adsorption chiller

WANG Dechang, WU Jingyi, WANG Ruzhu, DOU Weidong

期刊论文

Application of semi-analytical finite element method to analyze the bearing capacity of asphalt pavements

Pengfei LIU, Dawei WANG, Frédéric OTTO, Markus OESER

期刊论文

Dynamic characteristics analysis of active constrained layer damping plate with various boundary conditions

Jing LU, Yu XIANG, Qiao NI

期刊论文

Buffer capacity of granular matter to impact of spherical projectile based on discrete element method

Ying YAN, Pengfei LI, Shunying JI

期刊论文

Protein adsorption in two-dimensional electrochromatography packed with superporous and microporous cellulose beads

Dongmei WANG, Guodong JIA, Liang XU, Xiaoyan DONG, Yan SUN

期刊论文

Polypropylene microplastics alter the cadmium adsorption capacity on different soil solid fractions

期刊论文

Analytical algorithms of compressive bending capacity of bolted circumferential joint in metro shield

期刊论文

A method to calculate working capacity space of multi-DOF manipulator and the application in excavating

Baochen WEI, Feng GAO

期刊论文

Foundations bearing capacity subjected to seepage by the kinematic approach of the limit analysis

Mehdi VEISKARAMI, Ghasem HABIBAGAHI

期刊论文

Analysis on shear capacity of prestressed concrete spatial connections

XUE Weichen, LIU Zhenyong, JIANG Dongsheng

期刊论文

Undrained seismic bearing capacity of strip footing adjacent to a heterogeneous excavation

期刊论文

Ultimate bearing capacity of strip footing resting on clay soil mixed with tire-derived aggregates

期刊论文

Evaluation of the power-generation capacity of wearable thermoelectric power generator

Yang YANG, Jing LIU,

期刊论文