Mathematical Modeling of Fluid Flow in a Water Physical Model of an Aluminum Degassing Ladle Equipped with an Impeller-Injector

In this work, a 3D numerical simulation using a Euler–Euler-based model implemented into a commercial CFD code was used to simulate fluid flow and turbulence structure in a water physical model of an aluminum ladle equipped with an impeller for degassing treatment. The effect of critical process parameters such as rotor speed, gas flow rate, and the point of gas injection (conventional injection through the shaft vs a novel injection through the bottom of the ladle) on the fluid flow and vortex formation was analyzed with this model. The commercial CFD code PHOENICS 3.4 was used to solve all conservation equations governing the process for this two-phase fluid flow system. The mathematical model was reasonably well validated against experimentally measured liquid velocity and vortex sizes in a water physical model built specifically for this investigation. From the results, it was concluded that the angular speed of the impeller is the most important parameter in promoting better stirred baths and creating smaller and better distributed bubbles in the liquid. The pumping effect of the impeller is increased as the impeller rotation speed increases. Gas flow rate is detrimental to bath stirring and diminishes the pumping effect of the impeller. Finally, although the injection point was the least significant variable, it was found that the “novel” injection improves stirring in the ladle.     

Heat stress affects some physiological and productive variables and alters metabolism in dairy ewes

Heat stress (HS) has a significant economic impact on the global dairy industry. However, the mechanisms by which HS negatively affects metabolism and milk synthesis in dairy ewes are not well defined. This study evaluated the production and metabolic variables in dairy ewes under controlled HS conditions. Eight Lacaune ewes (75.5 ± 3.2 kg of body weight; 165 ± 4 d of lactation; 2.31 ± 0.04 kg of milk per day) were submitted to thermoneutral (TN) or HS conditions in a crossover design (2 periods, 21 d each, 6-d transition). Conditions (day-night, 12–12 h; relative humidity; temperature-humidity index, THI) were: TN (15–20°C; 50 ± 5%; THI = 59–65) and HS (28–35°C; 45 ± 5%; THI = 75–83). Ewes were fed ad libitum and milked twice daily. Rectal temperature, respiratory rate, feed intake, water consumption, and milk yield were recorded daily. Milk and blood samples were collected weekly. Additionally, TN and HS ewes were exposed to glucose tolerance test, insulin tolerance test, and epinephrine challenge. Heat stress reduced feed intake (?11%), and increased rectal temperature (+0.77°C), respiratory rate (+90 breaths/min), and water consumption (+28%). Despite the reduced feed intake, HS ewes produced similar milk to TN ewes, but their milk contained lower fat (?1.7 points) and protein (?0.86 points). Further, HS milk tended to contain more somatic cells (+0.23 log points). Blood creatinine was greater in HS compared with TN, but no differences in blood glucose, nonesterified fatty acids, or urea were detected. When glucose was infused, TN and HS had similar insulin response, but higher glucose response (+85%) was detected in HS ewes. Epinephrine infusion resulted in lower nonesterified fatty acids response (?215%) in HS than TN ewes. Overall, HS decreased feed intake, but milk production was not affected. Heat stress caused metabolic adaptations that included increased body muscle degradation and reduced adipose tissue mobilization. These adaptations allowed ewes to spare glucose and to avoid reductions in milk yield.     

Prevalence of Listeria monocytogenes in fresh and fermented Italian sausages and ribotyping of contaminating strains

Listeria monocytogenes has been detected in fresh as well as dry and semidry fermented sausages, rendering preparation and consumption of these products as a potential risk to human health. The aims of this study were (1) to evaluate the L. monocytogenes prevalence in 288 fresh and 237 fermented sausages produced in northern Italy; (2) to quantify the average pathogen Most Probable Number (MPN) per g of sausage; (3) to evaluate the sausage strain genetic diversity by automated PvuII ribotyping; and (4) to predict the pathogenicity lineage of these isolates determining their DuPont Identification Library Codes (DUP-IDs) by EcoRI ribotyping. The overall prevalence of L. monocytogenes in the sampled sausages was 28.2%. The percentage of L. monocytogenes positive fresh sausages was significantly higher than that of fermented sausages (i.e. 38.9 vs 15.2%), which had a pathogen load always lower than 10 MPN/g. In contrast, 16.1% of fresh sausages were contaminated by 10 to 100 MPN/g and 20.5% had more than 100 MPN/g. PvuII successfully discriminated sausage isolates with a Simpson's numerical index of discrimination of 0.637. A total of 12 and 9 different PvuII ribogroups were identified among 47 fresh and 24 fermented randomly selected sausage strains, respectively. Six of those ribogroups were shared between strains contaminating both kinds of sausages. According to the evaluation of the strain DUP-IDs, the majority of the isolates investigated in this study were part of the type II L. monocytogenes pathogenicity lineage, but type I lineage strains were identified among fermented sausage isolates. In conclusion, L. monocytogenes prevalence in Italian sausages was estimated to be around 28.2%. However, 84.2% of the samples were contaminated by less than 100 MPN of L. monocytogenes per g and the majority of L. monocytogenes contaminating strains would be classified in the type II pathogenicity lineage, including serotypes 1/2a, 1/2c and 3a.     

Practical method for estimating the power and energy delivered by photovoltaic modules operating under non‐standard conditions

This work describes a method developed for estimating the energy delivered by building integrated photovoltaics systems operating under non‐standard conditions of irradiance and temperature. The method is based on calculation of the maximum power (P_Gmax) supplied by the modules array as a function of irradiance and ambient temperature, achieved by simulating its I–V and P–V curves using an algorithm which needs only the performance parameters supplied by the manufacturers. The energy generated by the PV system is estimated from monthly average values of P_Gmax calculated for using monthly average values of ambient temperature and irradiance obtained from data measured during 2 years. The method is applied to crystalline Si modules and tested by comparing the simulated I–V and P–V curves with those obtained by outdoor measurements as well as for comparing the energy produced during the years 2009 and 2010 with a 3.6 kWp building integrated photovoltaics system installed at the Universidad Nacional located in the city of Bogotá, Colombia, at 4°35′ latitude and 2.580 m altitude. The contrast of the simulated I–V and P–V curves for two different types of commercial Si‐modules with those experimentally obtained under real conditions indicated that the simulation method is reliably. Copyright © 2012 John Wiley & Sons, Ltd.     

The effect of surface preparation on the bond interface between FRP sheets and concrete members

Fiber-reinforced polymer (FRP) composite wraps have been established as an effective method for rehabilitation and strengthening of concrete structures. They are being increasingly used as an alternative to steel for reinforcing and strengthening of concrete structures. This paper presents the experimental and analytical results of the influence of concrete surface treatment and the type of FRP sheets on the bonding strength of concrete-FRP sheet. The FRP sheets were bonded to concrete beams in two opposite sides using an epoxy resin. Variables included the type of fiber (C1, C5, and GE) and the surface treatment (water jet and sanding). With changing the surface treatment of concrete surface preparation and the type of fiber sheets, the bonding strength, bonding load–strain response and failure modes were investigated. The concrete specimens with surface roughened with water jet showed much better bonding strength than those roughened with an ordinary sander. Equations for predicting the bond load failure of concrete specimens externally bonded with carbon and glass fiber sheets compared well with those of experimental.     

Patenting and licensing by Spanish firms: Available survey evidence

This paper presents the results of the OEPM (Spanish Patent and Trademark Office)/OECD (Organisation for Economic Co-operation and Development) survey on the economic and financial uses of patents carried out in 2008 among Spanish business applicants of OEPM patents. It also summarizes evidence from previous surveys. All available information indicates that only a few Spanish firms holding patents license them out. Results from the OEPM/OECD survey also reveal that obtaining public support is the first financial use of patents for Spanish firms. Responses to the same OECD questionnaire by EPO patent applicants from several European countries are quite different: licensing out is an extended practice among EPO patent holders from different countries, including Spain, and convincing venture capitalists and private investors are their two most important financial uses of patents. In our view this suggests that there are significant differences across European countries as regards the development of national technology markets and results from international surveys are driven by responses from the largest and more developed countries. The drivers and actors in markets for patents that only protect inventions nationally may be quite distinct from those in markets for patents that protect inventions regionally, such as EPO patents within Europe.     

Restarted Iterated Pareto Greedy algorithm for multi-objective flowshop scheduling problems

Multi-objective optimisation problems have seen a large impulse in the last decades. Many new techniques for solving distinct variants of multi-objective problems have been proposed. Production scheduling, as with other operations management fields, is no different. The flowshop problem is among the most widely studied scheduling settings. Recently, the Iterated Greedy methodology for solving the single-objective version of the flowshop problem has produced state-of-the-art results. This paper proposes a new algorithm based on Iterated Greedy technique for solving the multi-objective permutation flowshop problem. This algorithm is characterised by an effective initialisation of the population, management of the Pareto front, and a specially tailored local search, among other things. The proposed multi-objective Iterated Greedy method is shown to outperform other recent approaches in comprehensive computational and statistical tests that comprise a large number of instances with objectives involving makespan, tardiness and flowtime. Lastly, we use a novel graphical tool to compare the performances of stochastic Pareto fronts based on Empirical Attainment Functions.     

Modeling the Combining Site of the Human Asialoglycoprotein Receptor

A model for the carbohydrate recognition domain (CRD) and combining site of the human asialoglycoprotein (ASGP) receptor has been computed on the basis of the close sequence homology with the mannose-binding lectin (MBP), whose three-dimensional structure in complex with a ligand has been determined by crystallographic methods (Weis, W.I.; Drickamer, K.; Hendrickson, W.A. Nature 1992, 360: 127). Within the limitations of modeling methods, the model is compatible with data on ligand binding of the family C-type lectins, of which the MBP and the ASGP receptor are members. The model derived can serve as a guide for designing site-directed mutagenesis experiments in order to further elucidate the origins of specificity of the ASGP receptor toward galactose. In particular, the model focuses attention on the possible role of position 207 (MBP sequence numbering) in promoting galactose binding.