Analysis of particle-gun-derived dairy powder stickiness curves

The stickiness curves of a range of dairy powders were measured using a particle-gun rig. The stickiness curves for the powders were shown to run parallel but above the curve of the glass transition temperature (T_g) of amorphous lactose. By assuming that the amorphous lactose at the surface of the powder was in equilibrium with the exit conditions of the air from the particle gun, it was found that for any particular dairy powder sample, the amount of powder deposition measured on the particle-gun target disc collapsed into a single function of the temperature difference by which the amorphous lactose T_g at the surface was exceeded. The x-axis intercept of these plots was calculated and designated as (T−T_g)_crit, characterizing the conditions for initiation of stickiness of the powder. The sensitivity of each powder to stickiness problems when placed in conditions where the critical T−T_g value at the surface is exceeded was quantified with the slope of the plot. These results show that it is the amorphous lactose component that is probably the main cause of stickiness in dairy powders and demonstrates how the particle-gun rig can be used to characterize the stickiness behaviour of powders over a wide range of conditions with two parameters.     

Benchmarking of chemical flowsheeting software in fuel cell applications

The use of chemical flowsheeting software has become an integral part of the evaluation of the performance of fuel cell systems. There are, however, aspects that have to be kept in mind when comparing the results obtained in different system studies. If care is not taken, the obvious merit of one system over another could later be found to be induced by the software used for the study, more than by a superior systems layout. Some causes of these deviations are discussed based on a comparative system study, which was carried out using three different types of chemical simulation software. It is found that even though there appears to be no differences on an overall level, significant differences are found when examining at a more detailed level. The differences are found to be caused by differing thermodynamic data relating to the steam reforming section of the fuel cell system. Some of the deviations are also believed to be caused by convergence-related issues.     

Determination of amorphous interfacial phases in Al2O3/SiC nanocomposites by computer-aided high-resolution electron microscopy

The analysis of thin amorphous layers in transmission electron microscope imaging has always been rendered difficult by the sample geometry conditions which must be met in order to single out the electronic scattering due to the amorphous phase from the overlapping crystalline diffraction fringes. This is the case of Al₂O₃/SiC nanocomposites in which spherical fine SiC particles are entrapped into the Al₂O₃-matrix grains. The spherical geometry of the SiC dispersoids involves a circular phase boundary in the thin foil which is hardly examined by conventional high-resolution techniques. In this paper an alternative technique of computer-aided high-resolution microscopy is proposed for imaging the presence of non-crystalline third phases at the interface of the alumina matrix and the silicon carbide nanosized particles in Al₂O₃/SiC nanocomposites. Implications regarding the effect of the observed layer on some toughening mechanisms proposed in literature for this materials are included.     

A new method of bimodal support preparation and its application in Fischer–Tropsch synthesis

A simple preparation method of bimodal silica was developed by introducing SiO₂ sol into large pores of SiO₂ gel pellet directly. Cobalt supported on this kind of bimodal silica support, exhibited remarkably high activity in liquid-phase Fischer–Tropsch synthesis, which was attributed to its bimodal structure having not only a higher surface area but also a larger pore size. The support with a large surface area allowed highly dispersed cobalt particle and its large pore size improved the diffusion of reactants and products.     

Combustion of fly-ash carbon: Part II: Thermodynamic aspects and calorimetric experiment

Thermodynamic aspects of carbon combustion are discussed. At lower temperatures (<400°C), carbon dioxide is the dominant species in the reacting system. Thermodynamic calculations indicate that at low temperatures methane can be produced. Based on literature data, the reaction rate of methane generation is low and therefore the methane combustion represents probably only a marginal contribution to the overall energy balance. Calorimetric experiments proved that impregnation of pelletized carbon fly-ash samples by sodium and/or potassium carbonates have beneficial effect on conversion of CO to CO₂. The value of the effective heat of combustion, calculated from CO and CO₂ outlet concentrations, increased for sample modified by Na₂CO₃ by 5% and for sample modified with K₂CO₃ almost by 20%.     

Performance of a novel bent-up bars system not interacting with concrete

Increasing the bending and shear capacities of reinforced concrete members is an interesting issue in structural engineering. In recent years, many studies have been carried out to improve capacities of reinforced concrete members such as using post and pre-tensioning, Fiber Reinforced Polymer and other techniques. This paper proposes a novel and significant technique to increase the flexural capacity of simply supported reinforced concrete beams. The proposed method uses a new reinforcement bar system having bent-up bars, covered with rubber tubes. This technique will avoid interaction of bent-up bars with concrete. They are located in the zone where compressive and tensile forces act against one another. The compressive force in the upper point of the bent-up bars is exerted to the end point of these bars located under neutral axis. Moreover, the tensile stress is decreased in reinforcements located under the neutral axis. This will cause the Reinforced Concrete (RC) beam to endure extra loading before reaching yield stress. These factors may well be considered as reasons to increase bending capacity in the new system. The laboratory work together with finite element method analysis were carried out in this investigation. Furthermore, bending capacity, ductility, strength, and cracking zone were assessed for the new proposed system and compared with the conventional model. Both the FEM simulation and the experimental test results revealed that the proposed system has significant impact in increasing the load bearing capacity and the stiffness of the RC beams. In the present study, an equation is formulated to calculate bending capacity of a new reinforcement bar system beam.     

Practical optimization of deployable and scissor-like structures using a fast GA method

This paper addresses practical sizing optimization of deployable and scissor-like structures from a new point of view. These structures have been recently highly regarded for beauty, lightweight, determine behavior, proper performance against lateral loads and the ability of been compactly packaged. At this time, there is a few studies done considering practical optimization of these structures. Loading considered here includes wind and gravity loads. In foldable scissor-like structures, connections have a complex behavior. For this reason, in this study, the authors used the ABAQUS commercial package as an analyzer in the optimization procedure. This made the obtained optimal solutions highly reliable from the point of view of applicability and construction requirements. Also, to do optimization task, a fast genetic algorithm method, which has been recently introduced by authors, was utilized. Optimization results show that despite less weight for aluminum models than steel models, aluminum deployable structures are not affordable because they need more material than steel structures and cause more environmental damage.     

Border-search and jump reduction method for size optimization of spatial truss structures

This paper proposes a sensitivity-based border-search and jump reduction method for optimum design of spatial trusses. It is considered as a two-phase optimization approach, where at the first phase, the first local optimum is found by few analyses, after the whole searching space is limited employing an efficient random strategy, and the second phase involves finding a sequence of local optimum points using the variables sensitivity with respect to corresponding values of constraints violation. To reach the global solution at phase two, a sequence of two sensitivity-based operators of border-search operator and jump operator are introduced until convergence is occurred. Sensitivity analysis is performed using numerical finite difference method. To do structural analysis, a link between open source software of OpenSees and MATLAB was developed. Spatial truss problems were attempted for optimization in order to show the fastness and efficiency of proposed technique. Results were compared with those reported in the literature. It shows that the proposed method is competitive with the other optimization methods with a significant reduction in number of analyses carried.     

Room temperature synthesis of Cu[Fe(CN)6]·XH2O cube derived ferric oxide@cupric oxide alloy ball on nitrogen-doped graphene as highly efficient electrochemical water splitting

Establishing non-precious metals with high efficiency for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) electrocatalysis are extremely essential for renewable energy technologies. Herein, we achieve the synthesis of metal-organic framework precursor of Cu[Fe(CN)₆]·XH₂O cube at room temperature, which further derived ferric oxide@cupric oxide alloy ball. On this foundation, we creatively synthesized ferric oxide@cupric oxide alloy ball on nitrogen-doped graphene (NG@Fe₂O₃/CuO alloy ball), where Fe₂O₃/CuO alloy ball is evenly anchored on nitrogen-doped graphene. It is worth noting that nitrogen doping, reduction of graphene oxide and conversion of Cu[Fe(CN)₆]·XH₂O cube precursor into Fe₂O₃/CuO alloy ball can be simultaneously realized by facile one-step calcination. Moreover, synergistic effect between the nitrogen-doped graphene and Fe₂O₃/CuO alloy ball can enhance the overall electrocatalytic performance of the catalyst by playing specific roles. The outstanding catalytic activity, long-term durability and stability make NG@Fe₂O₃/CuO alloy ball to become a promising non-precious electrocatalyst for electrochemical water oxidation.