A tribute to professor Roger Sargent: Intellectual leader of process systems engineering

This article and this issue of the AIChE Journal, is a tribute to Professor Roger Sargent who, as pioneer and intellectual leader of process systems engineering, has had a profound impact on the discipline of chemical engineering. Spanning more than five decades, his work has provided a strong mathematical foundation to process systems engineering through the development of sophisticated mathematical and computational tools for the simulation, design, control, operation and optimization of chemical processes. In this article we first give a brief overview of his career that included several leadership positions and the establishment of the Centre for Process Systems Engineering (CPSE) at Imperial College London. We next review his research contributions in the areas of process modeling, differential algebraic systems, process dynamics and control, nonlinear optimization and optimal control, design under uncertainty, and process scheduling. We highlight the tremendous impact that he has had through his students, students' students, and his entire academic family tree, which at present contains over 2000 names, probably one of the largest among the academic leaders of chemical engineering. Finally, we provide a brief overview of him as a modest and charming individual with a wonderful sense of humor. He is without doubt a true intellectual giant who has helped to expand the scope of chemical engineering by providing a strong systems component to it, and by establishing strong multidisciplinary links with other fields. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2951–2958, 2016     

Semicontinuous heterophase copolymerization of vinyl acetate and butyl acrylate

Vinyl acetate (VAc) and butyl acrylate (BuA) were copolymerized in heterophase by a semicontinuous process (unseeded) and compared with the seeded semicontinuous microemulsion polymerization of the same monomers. A mixture of sodium dodecyl sulfate (SDS) and poly(ethylene oxide) dodecyl ether (Brij‐35®) were used as surfactants. The effects of monomer addition rate (R_a) and surfactants concentrations (4 or 1 wt % with respect to the initial mixture of reaction) on polymer and latex properties were studied. High copolymer content latexes (24–36 wt %) with average particle diameters (D_p) from 38 to 55 nm and relatively narrow particle size distributions, high polymerization rates, weight ratios of polymer to surfactant (P/S) from 13.3 to 32.8 were obtained. The number‐average molecular weights (M_n) were between 96,000 and 188,000 g/mol. Homogeneous copolymer compositions were obtained throughout the reaction for both, seeded and unseeded processes, which is not possible by the usual batch microemulsion process. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Optimal design of water pipeline networks for the development of shale gas resources

One of the major concerns in shale gas production is water management. Millions of gallons of water are injected to fracture each well and a significant amount returns to the surface as flowback. Operators are increasingly reusing flowback to reduce freshwater consumption and impaired water disposal. Because of this, networks of water pipelines in U.S. shales are growing fast. This work is aimed at addressing the optimal planning of shale gas operations in multiple wellpads together with the design of water distribution networks (WDN). We propose a multiperiod mixed-integer linear programming model to solve the challenging stay-or-mobilize trade-off. The proposed model permits to schedule operations at a detailed level, accounting for the WDN required to maximize the reuse of impaired water. We present illustrative examples involving up to 20 pads, 4 frac-crews, and 100 wells developed over 1 year, showing that the design of the WDN can be effectively optimized.     

Continuous-Flow UV Liquid Food Pasteurization: Engineering Aspects

Ultraviolet (UV)-C treatments are a promising technology for liquid food pasteurization as an alternative to heat treatments. However, the design of efficient UV reactors to reduce pertinent microorganisms and comply with current food safety goals is still an engineering challenge due to the low penetration depth of UV light in liquid foods with high UV absorbance and suspended particles, and the variations in the residence time of the product in the UV reactors. This review focuses on physical aspects of UV radiation related to the essential product and processing parameters for the design of UV reactors. The UV equipment available for liquid food processing is described and the main drawbacks and advantages are discussed.     

Biodiesel Production by Enzymatic Catalysis Process Using Two Analytical Ways： Gas Chromatography and Total Glycerol Determination

Currently, biodiesel is presented as one of the best alternatives for gradually replacing the use of fossil fuels, but it has some factors that make it economically impractical if it does not have a government support. For this reason, research efforts focused on this area have been responsible for optimizing the process of biodiesel production by different catalytic routes to achieve greater efficiency at a lower cost. In this case, the biggest problem has been the high cost generated by an investigation, which in many occasions is the main factor to decide if an investigation could be carried out. Trying to reduce these costs, in the current study, we are using a technique of glycerol quantification by volumetric methods and comparing obtained results with the chromatographic method, which is conventionally used and comparatively much more expensive. Biodiesel employee was obtained by an enzymatic catalysis process varying one of three process variables：oil：alcohol molar ratio, temperature and proportion of catalyst. The numerical differences obtained between the two quantification methods generated relative errors lower than 10%, resulting in some occasions lower than 1%. By gas chromatography analysis the best yield was obtained at the same conditions of the volumetric method, a temperature of 45 ℃, an oil：alcohol ratio 1：4 and 8 wt.% of catalyst, but a yield of 95.5% and 97.1%, respectively. Due to the high precision of gas chromatography, this method is used to carry out a surface response analysis obtaining as ideal operating conditions a temperature of 43.5 ℃, 8.9 wt.%. of catalyst and an oil：alcohol ratio 1：4.     

What do patent examiner inserted citations indicate for a region with low absorptive capacity?

Most studies of patents citations focus on national or international contexts, especially contexts of high absorptive capacity, and employ examiner citations. We argue that results can vary if we take the region as the context of analysis, especially if it is a region with low absorptive capacity, and if we study applicant citations and examiner-inserted citations separately. Using a sample from the Valencian Community (Spain), we conclude that (i) the use of examiner-inserted citations as a proxy for applicant citations, (ii) the interpretation of non-patent references as indicators of science-industry links, and (iii) the traditional results for geographical localization are not generalizable to all regions with low absorptive capacity.     

Effect of the porous stainless steel substrate shape on the ZrO2 deposition by vacuum assisted dip-coating

The effect of the support shape on the deposition of ZrO₂ by the vacuum-assisted dip-coating method was studied. Disc-shaped and tubular porous stainless steel substrates were used to obtain ZrO₂ coated supports for the synthesis of PdAu alloy composite membranes. The microstructure of the ZrO₂ modified supports was evaluated by scanning electron microscopy and confocal laser microscopy. Besides, a qualitative assessment of the porosity and roughness of the porous substrates was performed by confocal laser microscopy. Dense and continuous palladium-alloy films were deposited on top of the modified tubes after thirteen ZrO₂ deposition-calcination cycles. Cross-section EDS mapping and XRD diffraction analysis showed that a complete PdAu alloy formation was obtained even after annealing at 723 K in hydrogen stream during 5 days.     

The effect of traditional wind vents called zarceras on the hygrothermal behaviour of underground wine cellars in Spain

This paper studies the hygrothermal behaviour of traditional underground wine cellars in one of the most important wine growing areas of Spain, the Ribera del Duero, paying special attention to the effects of traditional wind vents called zarceras. The purpose is to highlight energy-saving practices that aid the design and renovation of similar constructions. This was carried out by monitoring the temperature and relative humidity inside two wine cellars of similar properties throughout 2007, one with a zarcera and the other without. The results of the analysis show that the existence of the wind vent does not increase the ventilation from May to August. On the other hand, from September to March, the zarcera favours ventilation, affecting both temperature and relative humidity. The interior temperature is more greatly affected by the exterior temperature, giving rise to greater variations, although this difference is of little importance for maturing wine (annual variation 2.5 °C more than the cellar without a zarcera). The interior relative humidity is reduced, reducing the risk of condensation and problems of mould (the cellar without a zarcera reached excessively high values, 97% as an annual average, compared to 91% in the cellar with a zarcera). Thus the existence of zarceras in underground cellars improves the overall hygrothermal behaviour, providing suitable conditions for maturing wine without air conditioning systems, an advisable element in the building of new underground wine cellars.