Specific features of the electrochemical processes in the bath of an ore-smelting furnace

The mechanism of electrolysis in an ore-smelting cell modeling a bath with a conducting solid material in the melt is considered. An analysis suggests that a number of technological parameters of an ore-smelting furnace can be indirectly controlled by a change in the constant component of the phase voltage and the volt-ampere characteristic of the interelectrode gap.     

Azimuthally oscillating membrane emulsification for controlled droplet production

A novel membrane emulsification (ME) system is reported consisting of a tubular metal membrane, periodically azimuthally (tangentially) oscillated with frequencies up to 50 Hz and 7 mm displacement in a gently cross flowing continuous phase. A computational fluid dynamics (CFD) analysis showed consistent axial shear at the membrane surface, which became negligible at distances from the membrane surface greater than 0.5 mm. For comparison, CFD analysis of a fully rotating ME system showed local vortices in the continuous phase leading to a variable shear along the axis of the membrane. Using an azimuthally oscillating membrane, oil‐in‐water emulsions were experimentally produced with a median diameter of 20–120 μm, and a coefficient of variation of droplet size of 8%. The drop size was correlated with shear stress at the membrane surface using a force balance. In a single pass of continuous phase, it was possible to achieve high dispersed phase concentrations of 40% v/v. © 2015 American Institute of Chemical Engineers AIChE J, 61: 3607–3615, 2015     

Analyzing the effects of technological,organizational and competition factors on Web knowledge exchange in SMEs

Internet technologies are increasingly being used within all knowledge management processes, including knowledge acquisition, knowledge exchange and knowledge use. Although technological issues are key drivers for Internet technologies adoption and use, organizational and environmental aspects have been found to be equally important. This paper extends previous studies on the use of Internet technologies and knowledge management by analyzing factors affecting Web knowledge exchange in small and medium-sized enterprises (SMEs). More specifically, by drawing on the technology–organization–environment framework, a model to examine how distinct contextual factors influence Web knowledge exchange in SMEs is developed. The hypotheses are tested by using structural equation modelling on a large sample of Spanish SMEs from different industries. Results suggest that IT expertise and commitment-based human resource practices positively affect Web knowledge exchange, with the latter being the strongest factor in our proposed model. In contrast, a negative relationship is found between competition and Web knowledge exchange.     

浅谈西班牙中型城市绿色基础设施战略如何为公众健康带来福祉：拉科鲁尼亚案例分析

绿色基础设施建设是一个强大的多尺度规划战略,它在全球范围内正以迅猛之势蓬勃发展,并形成了一个能够带来多种利益的复杂系统（法布士,1995;兹欧拉斯,2007,等）,包括公众的健康与福利。证据表明,它能提高生活质量,改善心理健康问题,增加幸福感。在这一战略中,绿色基础设施的选址、大小、质量以及可达性对于公众健康的改善有至关重要的作用。西班牙的拉科鲁尼亚市是一个高密度中型城市,这一案例值得人们关注。关于该市现状及新总体规划的研究阐明了应该如何通过运用景观生态原则来改善绿色规划、增加其带来的尤其是关于公众健康的利益。以SWOT研究为基础,本文将对该案例的不足进行解释说明,并思考其在绿色基础设施战略、实施过程以及设计方案中的影响。目前,已有众多研究突出了在类似于拉科鲁尼亚市的密集城市中整合与实施这些规划战略的必要性,因为它们能够改善公众健康,生活质量与景观,并作为一个有竞争力的全球优势发挥作用。本研究将阐述区域性规划在增强城市网络（西班牙北部）的空间连续性,继而将其开放至大西洋方面的必要性。     

The effect of different porous media on moisture loss and oil absorption profiles during frying using glass micromodels

Microstructure plays a key role in oil absorption during frying. The aim of this work was to improve our understanding of the relationship between microstructure and oil absorption, through the use of glass micromodels to obtain evidence of transport phenomena in three porous networks. Micromodels were saturated with water and partially immersed in oil at 190°C. Moisture and oil profiles were imaged to get water and oil saturation maps. Image and fractal analyses were performed to describe the morphology of the evaporation and oil fronts. Results showed that higher porosity facilitated the moisture removal and promoted greater oil absorption during cooling. The fractal dimension showed that microstructures with a relatively high number of fine capillaries were less stable and propitiated fingering during the advance of the evaporation front. In all matrices, the disruption of the surface oil film due to air penetration was a critical factor to stop oil imbibition. © 2015 American Institute of Chemical Engineers AIChE J, 62: 629–638, 2016     

Inventory pinch based,multiscale models for integrated planning and scheduling‐part II: Gasoline blend scheduling

Integration of planning and scheduling optimizes simultaneous decisions at both levels, thereby leading to more efficient operation. A three‐level discrete‐time algorithm which uses nonlinear models and integrates planning and detailed scheduling is introduced: first level optimizes nonlinear blend models via multiperiod nonlinear programming (NLP), where period boundaries are initially determined by the inventory pinch points; second level uses fixed recipes (from the first level) in a multiperiod mixed‐integer linear program to determine first an optimal production plan and then to optimize an approximate schedule which minimizes the total number of switches in blenders and swing tanks; third level computes detailed schedules that adhere to inventory constraints computed in the approximate schedule. If inventory infeasibilities appear at the second or the third level, the first‐level periods are subdivided and blend recipes are reoptimized. Algorithm finds the same or better solutions and is substantially faster than previously published full‐space continuous‐time model. © 2014 American Institute of Chemical Engineers AIChE J, 60: 2475–2497, 2014     

Continuous flow characterization of solid biomass in a reciprocating/rotating scraper tube: An experimental study

The performance of reciprocating/rotating scrapers has been assessed in a visualization study of the continuous flow hydrodynamics of air‐fluidized solid biomass under varying conditions of air flow rate and scraping velocities. A combination of low air flow rates and high scraping velocities results in more uniform flow of both types of biomass investigated. Power consumed by the reciprocating action of the scrapers increases with the scraping velocity but typically represents no more than 20% of the overall power consumption at the highest air flow rate applied. We also demonstrate that rotation of the scrapers superimposed on their reciprocating action gives higher flow rate of biomass and better mixing within the bulk solid compared to reciprocating action alone. The application of the reciprocating/rotating scraper technology described in this study represents a viable step forward in developing a continuous, large‐scale process for the microwave‐assisted decomposition of solid biomass to produce bio‐oils. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3732–3738, 2014     

Optimal maintenance scheduling of a gas engine power plant using generalized disjunctive programming

A new continuous‐time model for long‐term scheduling of a gas engine power plant with parallel units is presented. Gas engines are shut down according to a regular maintenance plan that limits the number of hours spent online. To minimize salary expenditure with skilled labor, a single maintenance team is considered which is unavailable during certain periods of time. Other challenging constraints involve constant minimum and variable maximum power demands. The objective is to maximize the revenue from electricity sales assuming seasonal variations in electricity pricing by reducing idle times and shutdowns in high‐tariff periods. By first developing a generalized disjunctive programming model and then applying both big‐M and hull reformulation techniques, we reduce the burden of finding the appropriate set of mixed‐integer linear constraints. Through the solution of a real‐life problem, we show that the proposed formulations are very efficient computationally, while gaining valuable insights about the system. © 2014 American Institute of Chemical Engineers AIChE J, 60: 2083–2097, 2014     

Nickel phosphonate MOF as efficient water splitting photocatalyst

A novel microporous two-dimensional(2D)Ni-based phosphonate metal-organic framework(MOF;denoted as IEF-13)has been successfully synthesized by a simple and green hydrothermal method and fully characterized using a combination of experimental and computational techniques.Structure resolution by single-crystal X-ray diffraction reveals that IEF-13 crystallizes in the triclinic space group Pi having bi-octahedra nickel nodes and a photo/electroactive tritopic phosphonate ligand.Remarkably,this material exhibits coordinatively unsaturated nickel(II)sites,free-P0₃H₂and-P0₃H acidic groups,a C0₂accessible microporosity,and an exceptional thermal and chemical stability.Further,its in-deep optoelectronic characterization evidences a photoresponse suitable for photocatalysis.In this sense,the photocatalytic activity for challenging H₂generation and overall water splitting in absence of any co-catalyst using UV-Vis irradiation and simulated sunlight has been evaluated,constituting the first report for a phosphonate-MOF photocatalyst.IEF-13 is able to produce up to 2,200 fimol of H₂per gram using methanol as sacrificial agent,exhibiting stability,maintaining its crystal structure and allowing its recycling.Even more,170μmol of H₂per gram were produced using IEF-13 as photocatalyst in the absence of any co-catalyst for the overall water splitting,being this reaction limited by the 0₂reduction.The present work opens new avenues for further optimization of the photocatalytic activity in this type of multifunctional materials.