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1.
The work includes development of a multiphase porous media model and magnetic resonance imaging (MRI) experiments to study microwave combination heating. Combination of electromagnetic, convective and radiant heating was considered. The material being heated was modeled as a hygroscopic porous medium with different phases: solid matrix, water and gas, and included pressure driven flow, binary diffusion and phase change. The three‐dimensional transport model was fully coupled with electromagnetics to include the effect of variable properties. MRI was used to obtain spatial temperature and moisture distributions to validate the model. The model demonstrated that high and low moisture materials behave differently under different combinations of heating and general guidelines for combining heating modes were obtained. Low moisture materials can be heated effectively using higher microwave power which is not possible in high moisture material. Cycling of microwave was found to be useful in distribution of excessive volumetric heat generated by microwaves. © 2011 American Institute of Chemical Engineers AIChE J, 2012  相似文献   

2.
Structure oriented screening techniques are discussed with regard to their usefulness and applicability in catalyst screening in research projects with different degrees of exploratory character. Structure oriented screening approaches were applied to build libraries for two target reactions in two case studies presented in this paper one challenging exploratory ammon-oxidation reaction for the conversion of C6-feedstocks to adipodinitrile precursors with currently no relevant useful materials and no technical solution known. In this study the structure driven approach helped to identify lead structures for the conversion. The second case study focuses on the oxidation of acrolein and methacrolein to the corresponding unsaturated acids. Here technical catalyst candidate materials are known and are applied in the actual industrial applications. Therefore, the focus of the second case study is to find a superior material or alternative candidate materials with improved properties with this research strategy. For both case studies the effectiveness of the structure based approach is evaluated and put into perspective with state of the art library design and research strategies in high throughput experimentation and combinatorial catalysis.  相似文献   

3.
In this study, a new biobased isosorbide urethane methacrylic monomer [isosorbide‐derived urethane dimethacrylate (Is‐UDMA)] was evaluated as a replacement for currently used bisphenol A glycerolate dimethacrylate (Bis‐GMA) based dental restorative materials. Dental composites were prepared at different Is‐UDMA and Bis‐GMA concentrations. For these composites, the photocuring kinetics, volumetric shrinkage, viscoelastic properties, water sorption, and solubility were evaluated. The photocuring kinetics, followed by real‐time IR spectroscopy, showed higher double‐bond conversion (DC) values for the formulations containing the Is‐UDMA monomer; the highest DC (82%) was achieved by the formulation prepared with only the Is‐UDMA monomer. The volumetric shrinkage was reduced to 23.7% as compared with the dental resin formulated with Bis‐GMA. The viscoelastic properties of the formulations containing both Is‐UDMA and Bis‐GMA monomers in a 50:50 composition were superior to the rest of the tested formulations, including those prepared with pure polymers. This behavior was explained in terms of a compromise between crosslinking and rigidity (or flexibility) of the resulting polymer network. A preliminary test on microleakage in a dental enamel demonstrated that the new Is‐UDMA monomer is a potential replacement for the Bis‐GMA monomer in dental restorative materials. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44591.  相似文献   

4.
In the last decade, single-phase high-entropy materials have attracted considerable research interest owing to their unexpected existence and unique combinations of properties. Recent development of 5-cation high-entropy carbides (HECs) has demonstrated alluring properties compared to the rule of mixtures and binary carbides. Proposed here is the development of ultrahigh-entropy carbides (UHECs) containing 6+ principal elements with greater combinatorial possibilities. The use of 6+ multi-cation compositions allows for the design of ceramics with further tunable properties, while likely possessing higher orders of entropic stabilization. There are 133 possible carbide compositions containing 6, 7, 8, or 9 refractory metal cations in equiatomic ratios. Candidate selection for fabrication and material testing was accelerated using a machine learning model that was originally trained to predict the synthesizability of five cation disordered metal carbides. Two compositions from each category of six through eight cations, one containing Cr and one without, plus the one possible nine cation carbide were fabricated and characterized. The potential for these 6+ cation UHECs as improved materials for oxidative environments is demonstrated by comparing the oxidation performance of a 5- and 7-cation system after 10 min at 1973 K in air. The oxidation behavior is correlated with Ellingham diagrams, and it is demonstrated that the 7-cation carbide has the ability to form a transitional stable 5+ cation HEC layer as elements preferentially form oxides, which results in significantly improved oxidation resistance.  相似文献   

5.
The effect of particle size distribution of alumina has been investigated for silica-free tabular alumina low cement castables( LCC). Three different combinations of alumina have been included in the matrix formulation of the castables. All the three combinations are composed of a bimodal reactive alumina and a fine ground monomodal reactive alumina. The first A1 and second A2 combinations are respectively composed of bimodal and monomodal aluminas from Alteo,with a different fine /coarse particles ratio for the bimodal alumina. The two Alteo combinations have been compared with a third combination C composed of a bimodal commercially available grade and a monomodal commercially available grade. Optimization of particle size packing has been performed for the three different formulations using the Dinger and Funk model. With this optimization,the two formulations based on Alteo material( PFR,PBR and PFR40) achieve the same level of performance in applicative tests( flowability,cold physical properties,mechanical resistance,crystalline phases,thermal shocks and corrosion) as reference solutions on the market.  相似文献   

6.
Chromatographic processes can be optimized in various ways. However, the two most prominent approaches are either based on statistical data analysis or on experimentally validated simulation models. Both approaches heavily rely on experimental data, the generation of which usually imposes a significant bottleneck on rational process design. Hence, here a closed‐loop optimization strategy is proposed in that an automated high throughput liquid handling platform is combined with a genetic algorithm. This setup enables process optimization on the mini‐scale and thus saves time as well as material costs. The practicability and robustness of the proposed high throughput method is demonstrated with two exemplary optimization tasks: first, optimization of the buffer composition in the capture step for a binary protein mixture (lysozyme and cytochrome), and second, optimization of multilinear gradient elution for the separation of a ternary mixture (ribonuclease and cytochrome, and lysozyme).  相似文献   

7.
A direct correlation between the materials property behavior with its associated ferroelectric domain mechanisms and the anisotropic component of the Landau free energy is established for binary PMN-PT (generation I) and ternary PIN-PMN-PT (generation II) relaxor ferroelectric single crystal material systems. In addition to their trade-off in material properties, the observed ferroelectric domain dynamic and the determined free energy anisotropies, especially as approaching phase transition, provide direct insights into the materials field-dependent behavior between the binary and ternary ferroelectric systems. Domain configuration features such as lamellar structures in binary PMN-PT and concentric oval-like structures in ternary PIN-PMN-PT result in different material responses to external stimuli. Compared to binary PMN-PT, the concentric oval-like domain structures of ternary PIN-PMN-PT result in a 20°C higher temperature range of field-dependent linear behavior, 40% increase in coercive electric field E C , ${E_C},$ higher elastic stiffness during ferroelectric domain switching, and lower electromechanical energy losses. Separation of the isotropic and anisotropic components in the Landau free energy reveals a higher anisotropic free energy contribution from the ternary system, especially at temperature for practical applications. The high anisotropic free energy found in the ternary PIN-PMN-PT system implies that the concentric oval-like domain structure contributes to reduced electromechanical energy losses and enhanced stability under external applied fields.  相似文献   

8.
Intercalation of beneficial anion into inorganic host has lead to an opportunity to synthesize various combinations of new organic–inorganic nanohybrids with various potential applications; especially, for the controlled release formulation and storage purposes. Investigation on the release behavior of 2,4-dichlorophenoxyacetate (2,4-D) intercalated into the interlayer of Zn–Al-layered double hydroxide (ZAN) have been carried out using single, binary and ternary aqueous systems of chloride, carbonate and phosphate. The release behavior of the active agent 2,4-D from its double-layered hydroxide nanohybrid ZANDI was found to be of controlled manner governed by pseudo-second order kinetics. It was found that carbonate medium yielded the highest accumulated release of 2,4-D, while phosphate in combination with carbonate and/or nitrate speeds up the release rate of 2,4-D. These results indicate that it is possible to design and develop new delivery system of latex stimulant compound with controlled release property based on 2,4-D that is known as a substance to increase latex production of rubber tree, Hevea brasiliensis.  相似文献   

9.
AN-VAc-AMPS三元共聚合研究   总被引:7,自引:0,他引:7  
介绍了丙烯腈 ( A N) -醋酸乙烯 ( VAc) (或丙烯酸甲酯 ( MA ) -2 -丙烯酰胺基 -2 -甲基丙磺酸 (英文缩写 AMPS)三元共聚合体系各组分竞聚率的测定方法 ,并比较三元共聚体系和二元共聚体系的AN /VAc竞聚率 ,对三元连续共聚进行了试验 ,讨论 A MPS含量与染色性的关系 ,聚合工艺条件与转化率关系。对聚合物溶液的流变性能及纺丝工艺 ,纤维的性能作了简单介绍。聚合及纺丝试验结果证明 ,以 AMPS为第三单体的三元共聚体系可纺性良好 ,所得纤维的物理性能、染色性能、吸水性和抗静电性均优于一般腈纶  相似文献   

10.
桑丽霞  李锋 《化工学报》2018,69(Z1):129-135
以二元碳酸盐(Li2CO3-K2CO3,BC,62:38,摩尔比)和三元碳酸盐(K2CO3-Li2CO3-Na2CO3,TC,1:2:1,摩尔比)为相变材料,以氧化镁为基体材料,通过混合烧结法制备陶瓷基复合蓄热材料。二元碳酸盐复合材料(BCC)和三元碳酸盐复合材料(TCC)的熔点与相应混合碳酸盐的熔点相近,分别为465.1℃和386.4℃,并在其最高使用温度(800℃)范围内维持较高的比热容;且复合材料的潜热值均大于150.0 J/g。基于XRD和SEM的表征分析,两种复合蓄热材料具有较好的化学稳定性,且基体材料能很好地混合支撑相变材料。两种复合材料分别进行50次热循环,其热物性参数没有发生明显变化,具有较好的热循环稳定性。  相似文献   

11.
Polymer materials are often mixed with inorganic materials in the bulk to enhance properties, including mechanical, electrical, thermal, and physical. Such property enhancements are induced not only by the physical presence of the filler but also significantly by the interaction of the polymer with the filler via altering the local properties of the polymer material. In this regard, recently layered silicate nanocomposites have been shown to be effective in modifying the polymer properties because of their high surface area of contact between the polymer and the high aspect ratio nanoparticle. Potential property enhancements should also occur in polymer nanocomposite thin films owing to nanoparticle orientation from film confinement effects. In this paper we investigate the effect of layered silicate nanoparticles on the phase behavior of a classic polymer blend using small angle neutron scattering and compare those results to phase diagrams obtained by high throughput combinatorial methods.  相似文献   

12.
Polyamide 6 (PA6)-based composites are of evolving interest due to its high strength, wear resistance, and barrier properties. The use of binary composites mostly with nanomaterial and glass fibers has been reviewed and presented in literature. However to obtain a balance of properties like stiffness, toughness, and strength along with cost reduction, ternary composites of PA6 have been designed. To achieve the balance, PA6 blend-based composites, with combination of microfiller/nanofiller or PA6 with combination micro-microfiller, PA6 with microfiller/nanofiller and fiber have been designed. The properties of PA6-based ternary hybrid composites depend on type of dispersed phase used, presence of compatibilizer, type of filler used (nanofiller or microfiller or fiber or hybrid) and combination of fillers used. However, a review in this direction is not available in literature. Here, in this study, an overall understanding of various fillers, dispersed phase, and their combinations can be understood along with the discussion on effect of these on tensile properties and morphology of hybrid composite. In this study, an attempt has been made to review the various fillers and dispersed phase and their combinations which have been used in designing the PA6 hybrid composite with good balance of stiffness, toughness, and strength.  相似文献   

13.
In order to improve the quality of paperboard (a well‐known packing material) surface by photocuring method, different formulations were developed with aliphatic epoxy diacrylate (EA‐1020) oligomer along with reactive monomers of various functionalities. The reactive monomers are tripropylene glycol diacrylate (TPGDA), a difunctional monomer, and trimethylol propane triacrylate (TMPTA), a trifunctional monomer. 2‐Benzyl‐2‐dimethylamino‐1(4morpholinophenyl) butanone‐1 (Irgacure 369), a photoinitiator (2%), was incorporated into the formulations to initiate photocuring reaction. The formulated solutions were coated on clean glass plate and irradiated under UV radiation of different intensities. Different physical properties like pendulum hardness and gel content of the cured films were studied. The formulation containing TMPTA showed better properties. After characterization of the films, these formulations were applied on paperboard surfaces and cured under the same UV radiation. Various physicomechanical properties such as pendulum hardness, tensile properties, surface gloss, adhesion, abrasion, and water uptake were studied. The best performance was obtained at 12 passes of radiation with 18% TMPTA‐containing formulation. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1774–1780, 2003  相似文献   

14.
核壳结构电池材料能从核心和壳体两方面产生协同作用,具有比容量高、氧化还原可逆性好、离子扩散速率高、成本低、安全性强等优点,在电池材料研究中有广泛应用。三元电池材料的核壳结构设计主要分为非电活性材料核壳结构设计、普通核壳结构设计、浓度梯度核壳结构设计、全浓度梯度核壳结构设计等;核壳结构三元电池材料的合成方法主要分为:化学共沉淀法、水热法、溶胶-凝胶法等,综述了核壳结构电池材料热力学、电化学、动力学性能,对核壳结构电池材料理论计算、数值模拟的研究现状和应用进行了阐述,最后简述了核壳结构正极材料的应用和展望。  相似文献   

15.
Following a detailed analysis of the experimental data on thermodiffusion coefficients of numerous binary hydrocarbon mixtures from over 90 experiments, four new algebraic expressions are proposed. As per these formulations, the thermodiffusion coefficient of binary n‐alkane mixtures can be expressed as a function of the chemical composition of the mixture and the mixture properties such as density and viscosity. Detailed experimental validation is presented using four n‐alkane series containing a wide range of combinations of n‐alkanes. Additionally, comparison with recently proposed neural network model and a model based on the principles of non‐equilibrium thermodynamics is also presented. It has been found that the proposed algebraic models are simple in formulations, are evaluated with least computational effort and yet have a very high accuracy in predicting the thermodiffusion coefficients. © 2012 Canadian Society for Chemical Engineering  相似文献   

16.
Interest in hybrid organicinorganic (HOI) materials has grown rapidly in the last two decades. The appeal of this broad class of materials can be attributed to the unique combinations of properties that can be achieved by combining an inorganic phase with an organic phase. HOI materials can be divided into two basic categories: homogeneous systems derived from monomers or miscible organic and inorganic components, and heterogeneous, phase-separated systems with domains ranging from angstroms to micrometers in size. The structure of the inorganic component is dependent on the interaction of many variables such as pH, water content, overall solution concentration, solvent composition, temperature, and time. Due to the complexity of HOI materials, a combinatorial/high-throughput approach to the development of novel materials is highly desired. The authors have recently developed a combinatorial workflow for the synthesis and characterization of HOI coatings. Initial experimentation conducted with the workflow was focused on the development of primers for corrosion protection derived from a HOI binder system and magnesium particles. Both the homogeneous and heterogeneous HOI binders were investigated. With just one iteration of the combinatorial workflow, heterogeneous, moisture-curable HOI binders were identified, which enabled the formation of magnesium-rich primers that provided excellent corrosion protection to an aerospace aluminum alloy (Al 2024).  相似文献   

17.
The results of experiments investigating the interrelated effects of biologically degradable nonionic and anionic synthetic detergents in a light duty liquid detergent are presented. The formulations studied explore the performance of various biodegradable nonionic candidates in the presence of a fatty based alkylolamide foam stabilizer and biologically “soft” alkyl aryl sulfonate at two levels of nonionic concentration. The nonionic detergents evaluated are all polyoxyalkylated, including products of natural and synthetic origin. Products based on unsaturated and secondary alcohols are included. Consumer and laboratory test data show that biologically degradable detergents cannot be directly substituted in formulations without first testing their effect on the formulation itself. The data also show that small differences in molecular weight or in saturation of the materials being used can be reflected materially by technical differences in the finished product. These differences are manifested by analytical determination, by consumer panel evaluation using a duplicated balanced incomplete block design, and by standard dishwashing evaluation. The consumer panel data relate to dermatological properties, general performance and suds stability. It is obvious that the big switch to biologically degradable surface active agents is not as smooth a changeover as had been hoped, this being especially true for smaller producers of chemical specialties who do not have extensive facilities for formulation testing. These data do, however, indicate that with a careful experimental approach and judicious experimentation that formulations having a performance superior to their nonbiodegradable counterparts can be prepared. It is also stressed that judiciously designed consumer panel evaluations can yield data that is just as precise and valid as can be obtained through some of the more sophisticated testing procedures that require investment in equipment and in training of test panels. Presented at AOCS Meeting, New Orleans, April 1964.  相似文献   

18.
以三元乙丙橡胶(EPDM)/乙烯-辛烯共聚物(POE)/聚丙烯(PP)为原料,在PP含量固定的情况下,将POE部分取代EPDM,采用动态硫化技术制备出EPDM/POE/PP三元热塑性橡胶材料(TPV),研究不同含量的POE对材料力学性能、流变性能和微观形貌的影响。结果显示,随着POE含量的增加,三元TPV材料的硬度和熔体质量流动速率不断增大;拉伸强度和断裂伸长率呈线性增大,当EPDM/POE/PP比例为45/40/15时,材料力学性能达到最大值。流变性能和微观形貌分析结果表明,EPDM/POE/PP三元TPV材料具有良好的综合性能。  相似文献   

19.
Catalytic combustion, which permits to burn lean fuel/air mixtures is the key to environmentally preferable utilization of natural gas as an energy source and to removal of organic combustible gases from industrial effluents. The range of potential applications of catalytic combustion is large and can vary in temperatures of operation. Successful wide implementation of existing and of new catalytic combustion technologies will largely depend on the availability of suitable low cost catalytic materials. Since no single material can meet all demands, development of new catalysts needs to be orchestrated with the specific requirements of a given technology. The challenge is to combine existing knowledge and expertise in the area of combustion catalysts with innovations in their synthesis, improved formulations and applications in new specific composite forms. This paper outlines the current state of art and then focuses on perovskites for applications below 1,000 K. Examples of highly active formulations and of further enhancement of their activity through controlled synthesis and suitable support combinations are given. Criteria for the design of highly performing materials for high temperature catalytic combustion are also presented.  相似文献   

20.
Recent advances such as directed evolution and high throughput experiments can generate recombinant protein libraries and screen them for properties of interest. However it is impractical to span the theoretical range of combinatorial library and hence predictive models using the limited experimental data are of invaluable use. In this work, we have developed a novel machine learning strategy using Support Vector Machine (SVM) to predict the folding nature of recombinant proteins from Cytochrome P450 family using available experimental data. The folding-status is determined by an empirical energy model based on pair-wise interactions. It is shown that applying similarity-kernel function to the SVM formulation enables inclusion of many body interaction terms without additional computational effort. This approach can be generalized to other recombinant families and different properties of interest. The inferences derived by analyzing the data using the new method are in agreement with published results.  相似文献   

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