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Simulation of the Electrical Resistance Sintering of Hardmetal Powders
Juan Manuel Montes,Francisco J. de la Viña,Íñigo Agote,Thomas Schubert,Francisco G. Cuevas,Yadir Torres,José María Gallardo,Jesús Cintas 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.2
The simulation of the electrical resistance sintering (ERS) of hardmetal powders has been studied. The ERS process canproduce a quick consolidation of electrical conductive powders by the simultaneous application of pressure and electricalcurrent. A model of the process has been developed, integrating three actions, namely, thermal, mechanical and electrical,and taking into account the nature of both the powders and the die where powders are placed. The model has been implementedin COMSOL Multiphysics, a finite element commercial program. This paper deals with the model fundamentals andhardmetal particular aspects, such as modelling properties of mixed powders and its thermal behaviour. Other parameters inthe model have been tuned to optimally fit the initial experimental data. To check simulation results, measurable parametershave been monitored during experimental tests with WC–6 wt% Co. Once the model was completed and put to work, resultsare discussed.
Matus-Aragon, Miguel Angel,Gonzalez-Ceron, Fernando,Salinas-Ruiz, Josafhat,Sosa-Montes, Eliseo,Pro-Martinez, Arturo,Hernandez-Mendo, Omar,Cuca-Garcia, Juan Manuel,Chan-Diaz, David Jesus Asian Australasian Association of Animal Productio 2021 Animal Bioscience Vol.34 No.11
Objective: The study aimed to evaluate the productive performance, carcass yield, size of digestive organs and nutrient utilization in Mexican Creole chickens, using four diets with different concentrations of metabolizable energy (ME, kcal/kg) and crude protein (CP, %). Methods: Two hundred thirty-six chickens, coming from eight incubation batches, were randomly distributed to four experimental diets with the following ME/CP ratios: 3,000/20, 2,850/19, 2,700/18 and 2,550/17. Each diet was evaluated with 59 birds from hatching to 12 weeks of age. The variables feed intake (FI), body weight gain (BWG), feed conversion (FC), mortality, carcass yield, size of digestive organs, retention of nutrients, retention efficiency of gross energy (GE) and CP, and excretion of N were recorded. Data were analyzed as a randomized block design with repeated measures using the GLIMMIX procedure of SAS, with covariance AR (1) and adjustment of degrees of freedom (Kendward-Roger), the adjusted means were compared with the least significant difference method at a significance level of 5%. Results: The productive performance variables BWG, mortality, carcass yield, fat and GE retention and excretion of N were not different (p>0.05) due to the diet effect. In the 3,000/20 diet, the chickens had lower values of FI, FC, crop weight, gizzard weight, retention, and retention efficiency of CP (p<0.05) than the chickens of the 2,550/17 diet. Conclusion: The Mexican Creole chickens from hatching to 12 weeks of age can be feed with a diet with 2,550 kcal ME and 17% CP, without compromising productive parameters (BWG, mortality, carcass yield) but improving retention and retention efficiency of CP.