A systematic approach for synthesizing a low-temperature distillation system

In this paper, by combining a stochastic optimization method with a refrigeration shaft work targeting method, an approach for the synthesis of a heat integrated complex distillation system in a low-temperature process is presented. The synthesis problem is formulated as a mixed-integer nonlinear programming (MINLP) problem, which is solved by simulated annealing algorithm under a random procedure to explore the optimal operating parameters and the distillation sequence structure. The shaft work targeting method is used to evaluate the minimum energy cost of the corresponding separation system during the optimization without any need for a detailed design for the heat exchanger network (HEN) and the refrigeration system (RS). The method presented in the paper can dramatical y reduce the scale and complexity of the problem. A case study of ethylene cold-end separation is used to il ustrate the application of the approach. Compared with the original industrial scheme, the result is encouraging.     

Metallurgical SHS Processes as a Route to Industrial-Scale Implementation: An Autoreview

The paper addresses to the practical development of a novel process technology for large-tonnage SHS-production of alloying agents and master alloys–metallurgical SHS process technology. The suggested and tested technique is based on use of various metallurgically produced allows, including dusty wastes of ferroalloy plants. The replacement of high-purity starting powders by less expensive and accessible ferroalloys afforded for transition from existing laboratory-scale fabrication of SHS materials to large-tonnage SHS manufacture.     

Tall oil fatty acid mixtures as a new approach to quality alkyds

Conclusions Tall oil fatty acids may replace up to 50% of linseed or soya fatty acids, using the High Polymer Alkyd Technique, to obtain similar dry rates and resistances of conventional all-linseed or soy long-oil vehicles. Tall oil fatty acids also can be substituted for 25% of either linseed or soya fatty acids without adverse effects on the drying rates of conventionally prepared long-oil alkyds. Tall oil fatty acids likewise may be used in conjunction with the alcoholysis type of alkyds by the use of the High Polymer Technique. These vehicles show properties similar to conventional resins prepared from linseed oil and improvements over resins based on soybean oil.     

A facile approach toward transition metal oxide hierarchical structures and their lithium storage properties

A simple, non-template, non-surfactant and environmentally friendly hydrothermal method is presented based on the controlled release of the reactants into the reaction solvents to induce slow nucleation and growth of three-dimensional hierarchical nanostructures of transition metal oxides. This method is a general approach, which can be used to prepare Co(3)O(4), CuO, and Ni(OH)(2)/NiO. These metal oxides with hierarchical nanostructures can be used as anode materials for lithium-ion batteries with good Li storage performance, e.g. high specific capacities and stable cyclability.     

Modern approach to overwound structures

Abstract

The use of metallic wires or hoops for overwrapping pressure vessels has a history going back at least as far as the thirteenth century. In recent years, the availability of reinforcing fibres with very high strength/weight ratios has given this ancient concept a new lease of life. This paper describes the early history of the subject and details the properties of the high performance fibres now available. The theory of tensioned overwinding as applied to both thick and thin walled vessels is developed and the use of tensioned overwinding of strong, light fibres in the construction of lightweight structures having a wide range of applications is described.     

Fabrication of hierarchical lattice structures from zirconia stabilized ceramics by micro-SLA 3D printing approach

The need for the new materials and advanced manufacturing techniques for achieving the highest characteristics of energy devices is an obvious trend. One of the possible ways to create structures for energy applications is to introduce complex geometries and promising features with additive manufacturing (AM). Using this approach, it is possible to create complex geometry and moreover decrease the weight of materials. In this paper, we developed the layer-by-layer fabrication approach of ceramic hierarchical lattice structures via the (micro-SLA) technology. As a feedstock material, the novel composition of partly stabilized-zirconia ceramics (6ScSZ, 8YSZ) was developed. Materials were selected as a solid slurry component due to high ionic conductivity at the working temperature of modern solid oxide fuel cells (SOFCs). For the sintering, the green body heat treatment process was optimized to one step, which decrease the time and production cost. The data from scanning electron microscopy and micro-CT shows that 112-layer samples of the octet truss did not show any critical defects, and the achieved relative density was close to the theoretical one. Totally, 22 samples with the total size of 6.5 mm * 6.5 mm * 2.8 mm and the diameter of struts in the range of 240–250 μm were fabricated at a rate of only 56 min per sample, using two modifications of advanced doped zirconia-ceramics. This study opens new opportunities for the development and transfer to the production of additive manufacturing of ceramics to build energy systems devices such as solid oxide fuel cells.     

A new approach to a bridging tensor

Bridging Model is an efficient micromechanical theory which can be used to predict the effective thermomechanical as well as strength properties of a fiber reinforced composite. The key to the Bridging Model is a bridging tensor, which was obtained on Eshelby's inclusion method [Huang and Zhou, Strength of Fibrous Composites, Vol. 53, Zhejiang University Press, Springer, Hangzhou, (2011)]. A different approach to the closed‐form expressions for the elements of a bridging tensor is presented in this work. The method is based on averaging the stress fields of a single‐fiber inclusion embedded within an infinite matrix subjected to various load conditions. By solving the bridging equations between the averaged stress components in the fiber and those in the matrix, the exact expressions for the bridging tensor elements are obtained. The Bridging Model can be established by neglecting some small quantities in the bridging tensor elements. Effective elastic moduli of a unidirectional (UD) composite are expressed as functions of a bridging tensor. Comparisons of predicted elastic properties of a total number of 18 UD composites on simplified and the exact bridging tensors are made. POLYM. COMPOS., 36:1417–1431, 2015. © 2014 Society of Plastics Engineers     

A macrokinetic approach to crystallization applied to a new thermoplastic polyimide (New TPI) as a model polymer

The application of a new macrokinetic approach to polymer crystallization is applied in this work to a new thermoplastic polyimide (New TPI) recently developed as a matrix of advanced polymer matrix composites. The slow crystallization kinetics presented by New TPI in the entire range between the glass-transition temperature and the melting point makes TPI an excellent model polymer for testing crystallization models. In the approach presented here the variation of the induction time with the temperature is included in the Nakamura model for nonisothermal crystallization, and a simplified expression of the kinetic constant as a function of the temperature is adopted. The proposed model is verified through a comparison with a complete set of experimental data, ranging from the melting point to the glass-transition temperature of the polymer, obtained in isothermal and nonisothermal conditions. Moreover phase transformation diagrams (TTT and CCT plots) are presented, providing a fundamental tool for understanding the crystallization behavior of semicrystalline matrices and to determine the more appropriate processing conditions. © 1995 John Wiley & Sons, Inc.     

Use of a minimum perturbation approach to predict TIM mutant structures

A minimum perturbation conformational search approach is usedto model the structures of the yeast triosephosphate isomerase(TIM) single mutant in which the catalytic base Glul65 is changedto Asp, and the double mutant in which Glul65 is changed toAsp and Ser96 to Pro. In chicken TIM this double mutant is referredto as a pseudo–revertant because some of the catalyticactivity lost due to the first mutation is regained when thesecond mutation occurs. Three minimum energy structures werecalculated for the Asp 165 conformation in the yeast TEM singlemutant and another three for the double mutant One of the calculatedminimum energy conformations for Aspl65 in the E165D structureagrees well with the X–ray structure. However, this conformationis not that of the lowest energy and is not one of the threemost common conformers for Asp found by Ponder and Richards.This suggests that when an amino acid is introduced it may notbe able to conform to the more general rules that apply to proteinstructures of evolutionary origin. While the van der Waals energylargely determines the allowed minima, the relative rankingof the final minima is determined by electrostatic effects andcan therefore be affected by the inclusion of crystal watersin the calculation. When the E165D calculation is repeated withan active–site water molecule fixed in its E165D X–raystructure position, the relative ranking of the minima shiftsand the X–ray conformation for Asp 165 is the lowest interactionenergy conformer. Two of the E165D calculated minimum energystructures are essentially identical to two of the S96P/E165Dminima. All of the calculated minima for both the E165D andS96P/E165D mutants position the Asp side chain such that theanti–orbital, and not the more basic syn–orbital,of the carboxylate would be utilized for proton abstraction.This observation may explain why the chicken TIM S96P/E165Dmutant, for which the X-ray structure indicates that the syn–orbitalis used, is a pseudo–revertant while the yeast TIM doublemutant is not; no X–ray structure is available for thelatter. The multiplicity of minima found in the present analysismakes clear that predicting the exact orientation of a singleside chain is not as simple as might be expected.     

Cellular automata as models of inorganic structures self-assembly (Illustrated by uranyl selenate)

The theory of cellular automata is applied to describe the self-assembly of inorganic structures on molecular and nanoscale levels based on the example of uranyl selenates. The automaton that reproduces the structural topologies observed in these compounds is constructed, and its properties are studied. It is shown that the growth of complicated structural complexes in inorganic compounds depends on the structure of the nucleus as the initial condition of automaton’s work and, despite the topological differences of the resulting structures, the mechanisms of local interactions in these systems are identical. Under some conditions, this unity of mechanism leads to the formation of disordered structures.     

Microlayer coextrusion as a route to innovative blend structures

Nanolayer and microlayer coextrusion is a method for combining two or three polymers as hundreds or thousands of alternating layers with individual layers as thin as tens of nanometers. The possibility for utilizing microlayer coextrusion as a tool for creating microplatelets of high aspect ration was explored. Polypropylene (PP) was combined with polyamide‐66 (PA66) in microlayers. A high volume fraction of PA66 microplatelets dispersed in PP was achieved by injection molding the microlayered materials at a temperature intermediate between the melting points of the two constituents. The difference in melting temperatures provided a broad processing window of about 60°C in which the PP layers melted to form the matrix whereas the PA66 layers remained in the solid state as dispersed microplatelets of high aspect ration. The resulting material had significantly improved oxygen barrier properties. An enhancement of 4–5 times over the barrier of the conventional melt blend resulted from increased tortuosity of the diffusion pathway.     

Aluminothermic SHS: The effect of silica sol added as a binder

Aluminothermic combustion of “Al-metal oxide” blends compacted in the presence of silica sol added as a binder was found to proceed at lower combustion temperatures and burning velocities as compared to those in the absence of sol. The results show that the addition of silica sols to green mixtures can be used as an effective approach to performing aluminothermic SHS reactions yielding new refractory composite materials at moderate temperatures of 1000–1600dgC.     

A combined relaxation-newton method as a new global approach to the computation of thermal separation processes

Two basically different methods, formerly used sequentially to solve multicomponent thermal separation problems, are now allowed to function simultaneously within a single algorithm to ensure a rapid yet stable convergence to the solution. By combining the stability of the Rose-Sweeney-Ball method with the rapidity of the Newton-Raphson method, the solution is easily reached without encountering the difficulties of employing these methods separately.     

Preparation of hierarchical mesoporous CaCO3 by a facile binary solvent approach as anticancer drug carrier for etoposide

To develop a nontoxic system for targeting therapy, a new highly ordered hierarchical mesoporous calcium carbonate nanospheres (CCNSs) as small drug carriers has been synthesized by a mild and facile binary solvent approach under the normal temperature and pressure. The hierarchical structure by multistage self-assembled strategy was confirmed by TEM and SEM, and a possible formation process was proposed. Due to the large fraction of voids inside the nanospheres which provides space for physical absorption, the CCNSs can stably encapsulate the anticancer drug etoposide with the drug loading efficiency as high as 39.7 wt.%, and etoposide-loaded CCNS (ECCNS) nanoparticles can dispersed well in the cell culture. Besides, the drug release behavior investigated at three different pH values showed that the release of etoposide from CCNSs was pH-sensitive. MTT assay showed that compared with free etoposide, ECCNSs exhibited a higher cell inhibition ratio against SGC-7901 cells and also decreased the toxicity of etoposide to HEK 293 T cells. The CLSM image showed that ECCNSs exhibited a high efficiency of intracellular delivery, especially in nuclear invasion. The apoptosis test revealed that etoposide entrapped in CCNSs could enhance the delivery efficiencies of drug to achieve an improved inhibition effect on cell growth. These results clearly implied that the CCNSs are a promising drug delivery system for etoposide in cancer therapy.     

Sulfides as a new class of stable cost-effective materials compared to organic/inorganic hole transport materials for perovskite solar cells

Perovskite solar cells (PSCs) have received a remarkable attention compared to the other types of solar cells due to their high carrier mobility, low recombination rate, and rapid increase in terms of efficiency in short time. However, two essential parameters being stability and cost are still challenging with these kinds of solar cells. Hole transport materials (HTMs) play an important role in PSCs as they can be effective in the charge transportation, determining the device stability and having a large share of cell costs, and overall resulting in the enhancement of open-circuit voltage (V_oc), short-circuit current (J_sc), and fill factor (FF). In addition to the organic HTMs which are widely used in PSCs, various inorganic HTMs mainly divided into the oxide and sulfide subgroups, have been developed in order to improve both stability and cost of PSCs. Herein, we provide an overview of the diverse types of HTMs, from organic to inorganic, especially oxide and sulfide inorganic HTMs and investigate the physical properties, synthesis, and their applications in various PSCs for both mesoporous and planar structure in the hope of encouraging further research and the optimization of these materials.     

Amperometric flow injection analysis as a new approach for studying disperse systems

Fast and simple quantitative determination in dispersed systems (layered double hydroxides - LDHs - suspensions in aqueous solutions) was performed by a procedure that couples flow injection and amperometric detection (FI-AM). LDH dispersions are injected in a continuous flow (1 mL min⁻¹) of 0.05 mol L⁻¹ KNO₃ solution and [Cu(H₂O)₆]²⁺, used as a probe, is detected at a glassy carbon electrode housed in a flat electrochemical cell. The current intensity, recorded at the selected working potential (−0.25 V vs Ag/AgCl/NaCl (3 mol L⁻¹)), presents a linear relationship with [Cu(H₂O)₆]²⁺ concentration and the procedure offers high sensitivity (slope = 0.036 μA/(μmol L⁻¹)), a low detection limit (=0.7 μmol L⁻¹) and a wide quantification range (4-200 μmol L⁻¹).The method was applied to [Cu(H₂O)₆]²⁺ determination in two particular LDH-aqueous solution dispersed systems: (1) [Cu(H₂O)₆]²⁺ scavenging by etilendiammintetraacetic acid (EDTA) modified Zn-Al-LDHs, and (2) [Cu(H₂O)₆]²⁺ release from a copper doped Mg-Al-LDHs. The results obtained are comparable to those reported in previous works using different quantification techniques. FI-AM determination is applied without sample pretreatment (solid-supernatant separation) providing a high sampling rate (above 120 samples h⁻¹) that allows a better comprehension of the processes, particularly at the initial stages.     

The liquid-liquid interface as a medium to generate nanocrystalline films of inorganic materials

Unlike the air-water interface, the organic-aqueous (liquid-liquid) interface has not been exploited sufficiently for materials synthesis. In this Account, we demonstrate how ultrathin nanocrystalline films of metals such as gold and silver as well as of inorganic materials such as semiconducting metal chalcogenides (e.g., CdS, CuS, CdSe) and oxides are readily generated at the liquid-liquid interface. What is particularly noteworthy is that single-crystalline films of certain metal chalcogenides are also obtained by this method. The as-prepared gold films at the toluene-water interface comprise fairly monodisperse nanocrystals that are closely packed, the nature and properties of the films being influenced by various reaction parameters such as reaction temperature, time, reactant concentrations, mechanical vibrations, and the viscosity of the medium. The surface plasmon band of gold is markedly red-shifted in the films due to electronic coupling between the particles. The shift of the surface plasmon band of the Au film toward higher wavelengths with an accompanying increase in intensity as a function of reaction time marks the growth of the film. Depending on the reaction temperature, the Au films show interesting electrical transport properties. Films of metals such as gold are disintegrated by the addition of alkanethiols, the effectiveness depending on the alkane chain length, clearly evidenced by shifts of the surface plasmon bands. A time evolution study of the polycrystalline Au and CdS films as well as the single-crystalline CuS films is carried out by employing atomic force microscopy. X-ray reflectivity studies reveal the formation of a monolayer of capped clusters having 13 gold atoms each, arranged in a hexagonal manner at the toluene-water interface. The measurements also reveal an extremely small value of the interfacial tension. Besides describing features of such nanocrystalline films and their mode of formation, their rheological properties have been examined. Interfacial rheological studies show that the nanocrystalline film of Ag nanoparticles, the single-crystalline CuS film, and the multilayered CdS film exhibit a viscoelastic behavior strongly reminiscent of soft-glassy systems. Though both CuS and CdS films exhibit a finite yield stress under steady shear, the CdS films are found to rupture at high shear rates. An important advantage of the study of materials formed at the liquid-liquid interface is that it provides a means to investigate the interface itself. In addition, it enables one to obtain substrate-free single-crystalline films of materials.