The Experts below are selected from a list of 282 Experts worldwide ranked by ideXlab platform
Weng-sing Hwang - One of the best experts on this subject based on the ideXlab platform.
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Numerical Simulation of the Liquid-Gas Interface Shape in the Shot Sleeve of Cold Chamber Die Casting Machine
Journal of Materials Engineering and Performance, 2007Co-Authors: Weng-sing HwangAbstract:A mathematical model has been developed to simulate the flow pattern of molten metal and to predict the liquid-gas interface shape in the shot sleeve of a Cold Chamber die casting machine during the injection stage. The flow pattern in the shot sleeve is known to be closely related to the extent of gas entrapment of molten metal in the sleeve during the injection operation. In this study, a Variable Spacing Even Mesh (VSEM) method is proposed to incorporate with a computational fluid dynamics technique, named SOLA-MAC, to simulate the flow pattern in the shot sleeve. SOLA-MAC can deal with free surface flow problems while the VSEM method is used to handle the problem where the space in the shot sleeve keeps decreasing as the plunger moves to push the molten metal. The model is then tested on the shot sleeve of a Cold Chamber die casting machine. Four plunger speeds are tested to demonstrate the effects on the flow pattern of molten metal in the shot sleeve. The critical speed found in this study is 38 cm/s and it is close to the reported critical speed under the conditions that the space between the plunger and the sleeve end is 5 cm in diameter and 30 cm in length, and the fill ratio is 50%. As the plunger speed is slower than the critical speed, the wave front propagates along the sleeve faster than the plunger and reflects against the end wall of the sleeve. The remaining air in the shot sleeve is entrained as the wave front enters to the gate. As the plunger speed is higher than the suggested critical speed, the melt is immediately pushed higher in front of the plunger and forms a surge. The surge traps air in the early stage of the injection process.
Renato Mendes Guimarães - One of the best experts on this subject based on the ideXlab platform.
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QUALIDADE FISIOLÓGICA DE SEMENTES DE Ocimum selloi BENTH. SOB CONDIÇÕES DE LUZ, TEMPERATURA E TEMPO DE ARMAZENAMENT O Physiological quality of Ocimum selloi Benth. seeds under conditions of light, temperature and storage time
2020Co-Authors: Larissa Corrêa, Suzan Kelly, Vilela Bertolucci, Renato Mendes GuimarãesAbstract:“Atroveran” or “elixir-paregorico” (Ocimum selloi Benth.) is a Brazilian species that produces an essential oil rich in methyl chavicol. This work aimed to evaluate the influence of light, temperature and time of storage in different environments on the germination and vigor of O. selloi seeds. We initially tested the influence of presence and absence of white light in a 12-hour photoperiod to determine the photoblastism of the seeds under different temperatures (20, 25, 30 and 35oC). The physiological quality of seeds conserved under two temperatures (room temperature and Cold Chamber) was tested at 0, 2, 4, 6, 8 10 and 12 months of storage. The species was classified as neutral photoblastic with germination at a wide temperature range (20oC-30°C). Germination was maintained for twelve months of storage in Cold Chamber at room temperature, but the vigor was reduced in seeds kept at room temperature after the sixth month of storage.
Rupinder Singh - One of the best experts on this subject based on the ideXlab platform.
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Comparisons of Process Capability in Cold Chamber Die Casting of Aluminium Alloy
Proceedings of the National Academy of Sciences India Section A: Physical Sciences, 2017Co-Authors: Rupinder SinghAbstract:The purpose of the present investigations is to study and compare the effect of processing parameters on process capability of Cold Chamber die casting of Al alloy. The study presented in this paper is based on a previously published macro model (based on Taguchi design). Castings prepared at proposed parametric settings have been studied and compared using X chart, R chart and process capability histogram (for functional validation of the parts). The study suggested significant improvement in dimensional accuracy and process capability (expressed in terms of sigma ‘σ’ limit) at proposed parametric settings.
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Cold Chamber DIE CASTING OF ALUMINIUM ALLOY: A CASE STUDY
Journal of Mechanical Engineering, 2017Co-Authors: Rupinder SinghAbstract:In the present work Cold Chamber die casting solution of Al alloy has been investigated as a case study of industrial component (crankcase). The study presented in this paper is based upon Taguchi based model on dimensional accuracy in Cold Chamber die casting. The castings prepared at proposed parametric settings have been studied for functional validation of the parts, as per statistical control point of view. The result of study highlights significant improvement in dimensional accuracy (as regards to statistical process control is concerned) at proposed parametric settings of Cold Chamber die casting process.
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Effect of Phase Pressure on Casting Properties in Cold Chamber Die Casting Process
Journal of The Institution of Engineers : Series C, 2013Co-Authors: Rupinder Singh, R. KapoorAbstract:This paper focuses on the parametric optimization of process parameter in Cold Chamber die casting for an industrial component (crank case). Three controllable factors of the Cold Chamber die casting process (namely: 1st phase pressure, 2nd phase pressure and limit switch position) were studied at three levels each by Taguchi’s parametric approach and single-response optimization was conducted to identify the main factor controlling surface hardness, weight of casting and dimensional accuracy (Δd). Castings were produced using aluminium alloy at recommended parameters through Cold Chamber die casting process. Analysis shows that in Cold Chamber die casting process the percentage contribution of 1st phase pressure, limit switch position and 2nd phase pressure for surface hardness is 84.17, 11.43 and 1.93 % respectively. While in the case of weight of cast component, the contribution of limit switch position is 52.26 %, followed by 1st phase pressure and 2nd phase pressure 34.77 and 9.65 % respectively. Further for Δd, contribution of 1st phase pressure is 64.55 %, limit switch position 27.71 % and 2nd phase pressure contributes 4.87 %.
Fan Jin-zhen - One of the best experts on this subject based on the ideXlab platform.
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Design Plan Analysis of Weight Loss on Small Tail Cold Chamber Die Casting Machine
Coal Mine Machinery, 2020Co-Authors: Fan Jin-zhenAbstract:Die casting machine tail board is one of the core components;its structure will directly affect the production quality and service life of die-casting machine.COSMOSWorks finite element software 160 tons die casting machine before and after weight loss tail of two programs were compared,and reached the tail board of Von Mises stress,displacement diagram.The results show that weight loss after the end of the stiffness and deflection plate small,realistic weight loss program.
Marcos Vinicius Meiado - One of the best experts on this subject based on the ideXlab platform.
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In situ or ex situ seed conservation: which is the more effective way to maintain seed longevity of an endangered cactus?
Plant Species Biology, 2016Co-Authors: Joana Paula Bispo Nascimento, Marcos Vinicius MeiadoAbstract:With restricted populations and a small number of individuals, Discocactus bahiensis Britton & Rose (Cactaceae) is an endangered species in Brazil and its capacity for the formation of seed banks in the soil and the maintenance of seed viability remains unknown. Thus, the aim of the present study was to determine the most efficient way to maintain viability during storage of seeds of D. bahiensis . Seeds were stored in paper bags and either kept in a Cold Chamber (7 ± 2°C) in the dark (ex situ conservation) or buried in the soil to a depth of 5 cm in an area of natural occurrence of the species (in situ conservation). Germinability of the seed banks was evaluated monthly for 20 months. During the first 10 months of storage, germinability of the seeds conserved in situ and ex situ was similar to that of recently collected seeds. After this period, a 70% reduction in germinability was found for the seeds maintained in situ and there was nearly complete loss of viability after 12 months of storage in the field (germinability < 10% in the last 8 months of the experiment), indicating the ability to form persistent soil seed banks. In contrast, the seeds stored in the Cold Chamber maintained greater than 70% germinability throughout the entire analysis period, demonstrating that ex situ conservation is the most efficient way to maintain the viability of the seeds of this endangered species.