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properties of a silver particle-coated and 1-dodecanethiol-modified superhydrophobic melamine sponge for oil

《化学科学与工程前沿(英文)》 2022年 第16卷 第8期   页码 1237-1246 doi: 10.1007/s11705-022-2140-8

摘要: A Ag particle-coated and 1-dodecanethiol-modified melamine sponge (Ag-DDT-MS) was prepared through surface roughness by coating silver particles and subsequent grafting of a hydrophobic long hydrocarbon chain. Superhydrophobic and 3D porous Ag-DDT-MS was characterized by Fourier transform infrared spectroscopy, scanning electron microscope, energy-dispersive X-ray spectroscopy, and X-ray diffraction. The water contact angle of Ag-DDT-MS reached 159.2°. Ag-DDT-MS exhibited excellent absorption capacity for high viscous oils and organic solvents, ranging from 42.8 to 105.2 g∙g−1. The absorbed oils can be easily collected by the mechanical pressing process, and the oil recovery rate was satisfactory, more than 90% after 20 recycles. Ag-DDT-MS material also demonstrated good stability and excellent compression-recovery ability, keeping 88.6% of the initial height after ten compression-release cycles.

关键词: melamine sponge     oil-absorbing material     hydrophobic     oil-water separation     oil absorption capacity    

工程材料研究中科学问题的思考

于翘

《中国工程科学》 1999年 第1卷 第3期   页码 1-4

摘要:

在不少场合下,航天用工程材料处在极端条件下工作,这就对材料提出许多特殊的要求,虽然国内外有一定的研究积累,但对更精确的模型和符合特定材料的损伤的状态方程,有待深一步研究。如高级弹头再入时气动加热和粒子云侵蚀以及两者耦合效应引起弹头防护材料增大后退量的问题;空中垃圾和微流星的高速碰撞对航天器的威胁;特别是核爆和激光武器对材料的损伤和破坏,实质上是辐射引起的热击波层裂破坏,这些都属于超高速碰撞对材料的响应问题。天线罩材料、吸波材料、红外隐身材料、电磁屏蔽材料都是具有不同波长电磁波的电磁功能材料,它们对固体介质的穿透、吸收、反射等会产生响应,不同的电磁功能材料,其宏观性能的物理参量不同,但有几个参量是通用的,如介电常数、磁导率和损耗角正切,搞清这些参量与材料微观结构的关系,可以为材料设计和材料创新提供科学依据。

关键词: 天线罩材料     吸波材料     红外隐身材料     电磁兼容材料    

Effect of the degree of template removal from mesoporous silicate materials on their adsorption of heavy oil

Farouq TWAIQ,M.S. NASSER,Sagheer A. ONAIZI

《化学科学与工程前沿(英文)》 2014年 第8卷 第4期   页码 488-497 doi: 10.1007/s11705-014-1459-1

摘要: The key aim of this study is to evaluate the adsorption of heavy oil from aqueous solutions with different oil contents over mesoporous silicate materials having different surfactant template contents. The mesoporous silicate materials have been synthesized from tetraethylorthosilicate as a silica precursor and cetyltrimethylammonium bromide as a template using the sol-gel technique. Four samples were prepared by (1) totally removing the template using the calcination process, (2) partially removing the template via ethanol extraction, (3) partially removing the template via water extraction, and (4) keeping the template as synthesized, respectively. These four samples have been characterized using X-ray diffraction, nitrogen adsorption, thermal gravimetric analysis and Fourier transformed infrared. The effect of the degree of template removal of these mesoporous materials for the oil removal has been investigated. The oil removal is inversely proportional to the surfactant content in the mesoporous material, being highest for the calcined sample but lowest for the as-synthesized sample. The kinetic of oil adsorption over the calcined material has been also studied and the data obtained fit well a second-order model.

关键词: heavy oil     mesoporous silicate material     kinetics     template removal     adsorption    

Characteristics and application of road absorbing solar energy

Zhihua ZHOU, Shan HU, Xiaoyan ZHANG, Jian ZUO

《能源前沿(英文)》 2013年 第7卷 第4期   页码 525-534 doi: 10.1007/s11708-013-0278-2

摘要: If the heat of road surface can be stored in summer, the road surface temperature will be decreased to prevent permanent deformation of pavement. Besides, if the heat stored is released, it can supply heat for buildings or raise the road surface temperature for snow melting in winter. A road-solar energy system was built in this study, and the heat transfer mechanism and effect of the system were analyzed according to the monitored solar radiant heat, the solar energy absorbed by road and the heat stored by soil. The results showed that the road surface temperature was mainly affected by solar radiation, but the effect is hysteretic in nature. The temperature of the solar road surface was 3°C–6°C lower than that of the ordinary road surface. The temperature of the solar road along the vertical direction was 2°C–5°C lower than that of the ordinary road. The temperature difference increased as the distance to the heat transfer tubes decreased. The average solar collector efficiency of the system was 14.4%, and the average solar absorptivity of road surface was 36%.

关键词: solar energy     road-solar energy system     road surface temperature     solar absorptivity of road surface     solar collector efficiency of system    

Preparation of solar selective absorbing CuO coating for medium temperature application

HUANG Qunwu, WANG Yiping, LI Jinhua

《化学科学与工程前沿(英文)》 2007年 第1卷 第3期   页码 256-260 doi: 10.1007/s11705-007-0046-0

摘要: A new method of preparing CuO solar selective absorbing coating for medium temperature is presented. After pretreatment, brass was overlaid with CuO by chemical plating. The effects of reactant concentration, reaction temperature and reaction time on the absorptivity of CuO coating were investigated. The optimized condition of preparing CuO coating was obtained. The CuO coating was analyzed with X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). In order to prolong the period of use, the CuO coating was protected by TiO. The experiment shows that the TiO/CuO coating is more heat-resistant, acid-resistant, and wear resistant than CuO coating, without losing absorptivity markedly. The TiO coating can reduce emissivity and protect the CuO coating.

关键词: photoelectron spectroscopy     temperature     pretreatment     absorptivity     microscopy    

Entropy flow, entropy generation, exergy flux, and optimal absorbing temperature in radiative transfer

Zeshao CHEN, Songping MO, Peng HU, Shouli JIANG, Gang WANG, Xiaofang CHENG,

《能源前沿(英文)》 2010年 第4卷 第3期   页码 301-305 doi: 10.1007/s11708-010-0006-0

摘要: Taking nonequilibrium radiative heat transfer between two surfaces as an example, the nonequilibrium thermodynamics of radiation is studied and discussed. The formulas of entropy flow, entropy generation, exergy flux, and optimal temperature of absorbing surface for maximum exergy output are derived. The result is a contribution to the thermodynamic analysis and optimization of solar energy utilization and can be applied in more complex radiative heat transfer cases.

关键词: radiative heat transfer     entropy generation     exergy     thermodynamics    

Liquid metal material genome: Initiation of a new research track towards discovery of advanced energy

Lei WANG, Jing LIU

《能源前沿(英文)》 2013年 第7卷 第3期   页码 317-332 doi: 10.1007/s11708-013-0271-9

摘要: As the basis of modern industry, the roles materials play are becoming increasingly vital in this day and age. With many superior physical properties over conventional fluids, the low melting point liquid metal material, especially room-temperature liquid metal, is recently found to be uniquely useful in a wide variety of emerging areas from energy, electronics to medical sciences. However, with the coming enormous utilization of such materials, serious issues also arise which urgently need to be addressed. A biggest concern to impede the large scale application of room-temperature liquid metal technologies is that there is currently a strong shortage of the materials and species available to meet the tough requirements such as cost, melting point, electrical and thermal conductivity, etc. Inspired by the Material Genome Initiative as issued in 2011 by the United States of America, a more specific and focused project initiative was proposed in this paper—the liquid metal material genome aimed to discover advanced new functional alloys with low melting point so as to fulfill various increasing needs. The basic schemes and road map for this new research program, which is expected to have a worldwide significance, were outlined. The theoretical strategies and experimental methods in the research and development of liquid metal material genome were introduced. Particularly, the calculation of phase diagram (CALPHAD) approach as a highly effective way for material design was discussed. Further, the first-principles (FP) calculation was suggested to combine with the statistical thermodynamics to calculate the thermodynamic functions so as to enrich the CALPHAD database of liquid metals. When the experimental data are too scarce to perform a regular treatment, the combination of FP calculation, cluster variation method (CVM) or molecular dynamics (MD), and CALPHAD, referred to as the mixed FP-CVM-CALPHAD method can be a promising way to solve the problem. Except for the theoretical strategies, several parallel processing experimental methods were also analyzed, which can help improve the efficiency of finding new liquid metal materials and reducing the cost. The liquid metal material genome proposal as initiated in this paper will accelerate the process of finding and utilization of new functional materials.

关键词: liquid metal material genome     energy material     material discovery     advanced material     room-temperature liquid alloy     thermodynamics     phase diagram    

Robust topology optimization of multi-material lattice structures under material and load uncertainties

Yu-Chin CHAN, Kohei SHINTANI, Wei CHEN

《机械工程前沿(英文)》 2019年 第14卷 第2期   页码 141-152 doi: 10.1007/s11465-019-0531-4

摘要: Enabled by advancements in multi-material additive manufacturing, lightweight lattice structures consisting of networks of periodic unit cells have gained popularity due to their extraordinary performance and wide array of functions. This work proposes a density-based robust topology optimization method for meso- or macro-scale multi-material lattice structures under any combination of material and load uncertainties. The method utilizes a new generalized material interpolation scheme for an arbitrary number of materials, and employs univariate dimension reduction and Gauss-type quadrature to quantify and propagate uncertainty. By formulating the objective function as a weighted sum of the mean and standard deviation of compliance, the tradeoff between optimality and robustness can be studied and controlled. Examples of a cantilever beam lattice structure under various material and load uncertainty cases exhibit the efficiency and flexibility of the approach. The accuracy of univariate dimension reduction is validated by comparing the results to the Monte Carlo approach.

关键词: robust topology optimization     lattice structures     multi-material     material uncertainty     load uncertainty     univariate dimension reduction    

Biodegradable, superhydrophobic walnut wood membrane for the separation of oil/water mixtures

《化学科学与工程前沿(英文)》 2022年 第16卷 第9期   页码 1377-1386 doi: 10.1007/s11705-022-2157-z

摘要: The preparation of environmentally friendly oil/water separation materials remains a great challenge. Freeze-drying of wood after lignin removal yields wood aerogels, which can be used as substrates to prepare fluorine-free environmentally friendly superhydrophobic materials, However, they are more suitable for absorption rather than filtration applications due to their poor strength. A study using cross-sections of pristine wood chips as substrates retains the original strength of wood, but the use of the cross-sectional of wood pieces limits their thickness, strength, and size. In this paper, a degradable fluorine-free superhydrophobic film (max. water contact angle of approximately 164.2°) with self-cleaning and abrasion resistance characteristics was prepared by a one-step method using pristine and activated walnut longitudinal section films as the substrate, with tetraethyl orthosilicate as a precursor and dodecyltriethoxysilane as a modifier. The tensile strength results show that superhydrophobic films with pristine or activated wood substrates maintained the strength of pristine wood and were 2.2 times stronger than the wood aerogel substrate. In addition, after cross-laminating the two samples, the films had the ability to separate oil and water by continuous filtration with high efficiency (98.5%) and flux (approximately 1.3 × 103 L∙m‒2∙h‒1). The method has potential for the large-scale fabrication of degradable superhydrophobic filtration separation membranes.

关键词: wood nanotechnology     superhydrophobic     biodegradable     surface modification     oil/water separation    

A novel approach to minimizing material loss for computer numerical control flank-regrinding of worn

《机械工程前沿(英文)》 2023年 第18卷 第3期 doi: 10.1007/s11465-023-0757-z

摘要: Flanks of end mills are prone to wear in a long machining process. Regrinding is widely used in workshops to restore the flank to an original-like state. However, the traditional method involves material waste by trial and error and dramatically decreases the potential regrinding. Moreover, over-cut would happen to the flutes of worn cutters in the regrinding processes because of improper wheel path. This study presented a new approach to planning the wheel path for regrinding worn end mills to minimize material loss and recover the over-cut. In planning, a scaling method was developed to determine the maximum size of the new cutter according to the similarity of cutter shapes before and after regrinding. Then, the wheel path is first generated by envelope theory to regrind the worn area with a four-axis computer numerical control grinder according to the new size of cutters. Moreover, a second regrinding strategy is applied to recover the flute shape over-cut in the first grinding. Finally, the proposed method is verified by an experiment. Results showed that the proposed approach could save 25% of cutter material compared with the traditional method and ensure at least three regrinding times. This work effectively provides a general regrinding solution for the worn flank with maximum material-saving and regrinding period.

关键词: flank-regrinding     worn end mill     wheel position and orientation     material loss     over-cut    

Cultivars and oil extraction techniques affect Cd/Pb contents and health risks in oil of rapeseed grown

《环境科学与工程前沿(英文)》 2023年 第17卷 第7期 doi: 10.1007/s11783-023-1687-z

摘要:

● Organic solvent extracted fewer Cd/Pb in rapeseed oil than physical pressing.

关键词: Rapeseed oil     Oil extraction technologies     Human health risk assessment     Cd/Pb-contaminated farmland     Substitute planting    

Co-hydrotreating light cycle oil-canola oil blends

Huali WANG, Hena FAROOQI, Jinwen CHEN

《化学科学与工程前沿(英文)》 2015年 第9卷 第1期   页码 64-76 doi: 10.1007/s11705-015-1504-8

摘要: Canola oil and light cycle oil (LCO) blends were co-hydrotreated over a commercial hydrotreating catalyst (NiMo/Al O ) to produce diesel fuel with a green diesel component. High hydrodeoxygenation, hydrodesulphurization and hydrodenitrogenation catalytic activities were achieved for all three feedstocks tested in the temperature range of 350–380 °C with a hydrogen pressure of 7 MPa and a gas/oil ratio of 800 nL/L. The hydrocracking conversion of the 360 °C+ materials in the feedstocks increased by 5% and 15% when 5 and 7.5 wt-% canola oil was added to the LCO, respectively. Compared to the pure LCO, the cetane index of the diesel product formed from hydrotreating the two canola oil-LCO blends increased by 2.5 and 4, respectively. Due to the higher hydrogen requirement to crack and deoxygenate the triglycerides contained in the canola oil, a higher hydrogen consumption was needed to hydrotreat the canola oil-LCO blends.

关键词: hydrotreating     co-hydrotreating     co-processing     canola oil     light cycle oil (LCO)    

A MATLAB code for the material-field series-expansion topology optimization method

《机械工程前沿(英文)》 2021年 第16卷 第3期   页码 607-622 doi: 10.1007/s11465-021-0637-3

摘要: This paper presents a MATLAB implementation of the material-field series-expansion (MFSE) topo-logy optimization method. The MFSE method uses a bounded material field with specified spatial correlation to represent the structural topology. With the series-expansion method for bounded fields, this material field is described with the characteristic base functions and the corresponding coefficients. Compared with the conventional density-based method, the MFSE method decouples the topological description and the finite element discretization, and greatly reduces the number of design variables after dimensionality reduction. Other features of this method include inherent control on structural topological complexity, crisp structural boundary description, mesh independence, and being free from the checkerboard pattern. With the focus on the implementation of the MFSE method, the present MATLAB code uses the maximum stiffness optimization problems solved with a gradient-based optimizer as examples. The MATLAB code consists of three parts, namely, the main program and two subroutines (one for aggregating the optimization constraints and the other about the method of moving asymptotes optimizer). The implementation of the code and its extensions to topology optimization problems with multiple load cases and passive elements are discussed in detail. The code is intended for researchers who are interested in this method and want to get started with it quickly. It can also be used as a basis for handling complex engineering optimization problems by combining the MFSE topology optimization method with non-gradient optimization algorithms without sensitivity information because only a few design variables are required to describe relatively complex structural topology and smooth structural boundaries using the MFSE method.

关键词: MATLAB implementation     topology optimization     material-field series-expansion method     bounded material field     dimensionality reduction    

Influence of different oil feed rate on bituminous coal ignition in a full-scale tiny-oil ignition burner

Chunlong LIU, Qunyi ZHU, Zhengqi LI, Qiudong ZONG, Xiang ZHANG, Zhichao CHEN

《能源前沿(英文)》 2013年 第7卷 第3期   页码 406-412 doi: 10.1007/s11708-013-0266-6

摘要: To reduce oil consumption during firing-up and partial-load operation, a tiny-oil ignition burner has been recommended. Through reacting-flow experiments performed on a full-scale experimental setup, the influence of different oil flow rates on bituminous coal combustion as well as flow rates without coal feed was analyzed. The ignition burner is identical to that normally used in an 800 MWe utility boiler. Under operating conditions with flow rates of 50, 100, and 150 kg/h, gas temperature distributions were measured in the burner. At the equivalent measuring points at the exits of the first and second combustion chambers, these distributions remained almost unchanged under a constant coal feed rate of 4 t/h. However on the burner centerline, distributions increased slightly with increasing flow rate. Different gas concentrations were measured at the center of the burner exit. For instance, the O concentration at the burner exit varied from 0.01% to 0.31% whereas CO concentrations were more than 10000 ppm. At the same coal feed rate of 4 t/h, burner resistances are 480, 600, and 740 Pa for oil flow rates of 50, 100, and 150 kg/h, respectively.

关键词: ignition     coal     burner     boiler     oil flow rate    

世界油气上游国际合作的形势和机会

童晓光

《中国工程科学》 2011年 第13卷 第4期   页码 15-19

摘要:

指出中国利用国外油气的必要性,重点分析了伊拉克、伊朗、巴西、加拿大、委内瑞拉和北美油气上游合作的机会及世界油气国际合作的合同变化趋势,提出了当前扩大油气上游国际合作的主要方向。

关键词: 油气上游国际合作     伊拉克     深水油气勘探     重油和油砂     非常规天然气    

标题 作者 时间 类型 操作

properties of a silver particle-coated and 1-dodecanethiol-modified superhydrophobic melamine sponge for oil

期刊论文

工程材料研究中科学问题的思考

于翘

期刊论文

Effect of the degree of template removal from mesoporous silicate materials on their adsorption of heavy oil

Farouq TWAIQ,M.S. NASSER,Sagheer A. ONAIZI

期刊论文

Characteristics and application of road absorbing solar energy

Zhihua ZHOU, Shan HU, Xiaoyan ZHANG, Jian ZUO

期刊论文

Preparation of solar selective absorbing CuO coating for medium temperature application

HUANG Qunwu, WANG Yiping, LI Jinhua

期刊论文

Entropy flow, entropy generation, exergy flux, and optimal absorbing temperature in radiative transfer

Zeshao CHEN, Songping MO, Peng HU, Shouli JIANG, Gang WANG, Xiaofang CHENG,

期刊论文

Liquid metal material genome: Initiation of a new research track towards discovery of advanced energy

Lei WANG, Jing LIU

期刊论文

Robust topology optimization of multi-material lattice structures under material and load uncertainties

Yu-Chin CHAN, Kohei SHINTANI, Wei CHEN

期刊论文

Biodegradable, superhydrophobic walnut wood membrane for the separation of oil/water mixtures

期刊论文

A novel approach to minimizing material loss for computer numerical control flank-regrinding of worn

期刊论文

Cultivars and oil extraction techniques affect Cd/Pb contents and health risks in oil of rapeseed grown

期刊论文

Co-hydrotreating light cycle oil-canola oil blends

Huali WANG, Hena FAROOQI, Jinwen CHEN

期刊论文

A MATLAB code for the material-field series-expansion topology optimization method

期刊论文

Influence of different oil feed rate on bituminous coal ignition in a full-scale tiny-oil ignition burner

Chunlong LIU, Qunyi ZHU, Zhengqi LI, Qiudong ZONG, Xiang ZHANG, Zhichao CHEN

期刊论文

世界油气上游国际合作的形势和机会

童晓光

期刊论文