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BiCMOS Process Simulations
Published in Chinmay K. Maiti, Introducing Technology Computer-Aided Design (TCAD), 2017
Process simulation is especially helpful in the initial phase of technology development. As device lots become more and more expensive, process modeling is increasingly important. Process simulation and modeling is increasingly sophisticated, but accuracy remains a problem. There is generally a time lag between the introduction of a particular process and its accurate modeling. Modeling of front-end processes has been facing challenges caused by a continuous reduction of the implant energies and of the thermal budgets of the annealing schemes from soak anneals to the spike anneals which are now used for production. The complexity of physical models is a major factor that impacts process simulation. Simplified physics minimizes computation time. With technology scaling, however, the need for ever more accurate doping/stress profiles has increased and complex physical models are added at each new generation. Also, the best models available are usually too complicated and slow to be used in multidimensional process simulation, so often compromises have to be made. It has to provide insight during design, optimization guidelines during implementation to manufacturing, and debug during large-scale manufacturing.
Isostearic Acids
Published in Brajendra K. Sharma, Girma Biresaw, Environmentally Friendly and Biobased Lubricants, 2016
Helen Ngo, Robert O. Dunn, Winnie C. Yee
To evaluate the economic feasibility of this zeolite-catalyzed isomerization process, a process simulation model for the production of isostearic acids was developed using the SuperPro Designer process simulation program, version 8.5 (Intelligen Inc., Scotch Plains, New Jersey). Process simulation is a model-based representation of technical processes and unit operations using computer software such as SuperPro Designer and Aspen Plus (Aspen Technology Inc., Burlington, Massachusetts). It is a valuable tool by which scientists and engineers assess the economics, process-development needs, and environmental impacts of a technology before committing to a full-scale implementation and commercialization. This tool has been successfully applied to determine the economic costs and to provide an understanding of the costs associated with a process. It has been used in evaluating the feasibilities of various technology areas including biodiesel production from refined soybean, rapeseed, and algal oils [62–64]; ethanol production by dry-grind process and wet milling process [65–69]; and the production of activated carbon from pecan shells and broiler litter [70,71].
Updates on electrospinning process models (part i)
Published in A. K. Haghi, Lionello Pogliani, Francisco Torrens, Devrim Balköse, Omari V. Mukbaniani, Andrew G. Mercader, Applied Chemistry and Chemical Engineering, 2017
Shima. Maghsoodlou, S. Poreskandar
Simulation is transition from a mathematical or computational model to the description of the system behavior based on sets of input parameters. It is often the only means for accurately predicting the performance of the modeled system. The investigation of simulation techniques is fairly a new area and various research in different fields are talking about it. Process simulation is a model-based representation that can be used for the design, development, analysis, and optimization of technical processes. Knowing about chemical and physical properties is a basic requisite to have an appropriate mathematical model (Fig. 2.1).15, 16
Experimental investigation of deep-hole micro-drilling of glass using LIPAA process
Published in Materials and Manufacturing Processes, 2022
Naser Abbasi, Mohammad Reza Razfar, S. Mehdi Rezaei, Khosro Madanipour, Mohsen Khajehzadeh
Based on studies of the LIPAA process mentioned above, it is observed that optimizing the process parameters, improving the machining conditions, increasing the ablation rate, and reducing costs are the goals of researchers in this field. However, most of this research was mainly limited to low depth plasma-assisted ablation. Besides, due to the lack of detailed study of the transparent material ablation mechanism in this process and the complexity of plasma interaction with transparent material, simplified assumptions were made. Process simulation while understanding the process mechanism can go a long way in improving process quality, preventing damages and optimizing parameters. Most of the studies in the LIPAA process are focused on creating texture and channel or engraving on transparent materials such as glass and polyamide. The drilling process has been rarely studied except by Zhang et al.[23,24] Mechanism of deep machining in this process which is different from low depth machining has not been studied. Mechanism of the glass deep drilling using LIPAA process and the effects of laser intensity on the morphology and profile of the produced hole is reported in this paper.
Development of a non-stoichiometric equilibrium model of downdraft gasifier
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2019
Pavan V Kashyap, Rose Havilah Pulla, Amit Kumar Sharma, Pankaj Kumar Sharma
Both kinetic and equilibrium modeling can also be done in ASPEN HYSYS and other chemical process simulation software. The equilibrium modeling is the simplest of the three and for certain types of gasifier designs, yield sufficiently accurate results. The equilibrium models can be further classified into: Stoichiometric models: The knowledge of the various reactions undergoing is necessary and the equilibrium constants of these are used for calculating the gas compositions (Zainal et al. 2001).Non-Stoichiometric models: These make use of the Gibbs free energy minimization method. All reactions proceed spontaneously toward the minimization of the Gibbs free energy of the system and thus a knowledge of only the thermal properties of the expected molecular species is required and not the individual reactions (Antonopoulos et al. 2012).
Syngas production from algae biomass gasification: the case of China
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2019
There have been very few studies conducted on the direct gasification of ocean algae in presence of air and steam as the gasification agents. Onwudili et al. (2013) used an Inconel batch reactor to produce syngas from Chlorella vulgaris, Spirulina platensis and Saccharina latissima under supercritical water gasification conditions. They showed that sodium hydroxide has a positive effect on the hydrogen concentration. The authors also found that sodium hydroxide can significantly reduce the yield of tar. Aziz and Zaini (2017) developed an integrated system, including algal drying, gasification, and chemical looping for converting biomass algae into hydrogen. Process simulation was carried out using Aspen Plus. The authors found that both moisture content and steam/biomass ratio have a significant effect on the total energy efficiency. Aziz (2017) used a steady state simulator SimSci Pro/II to simulate hydrogen production from algae biomass under supercritical water gasification. He found that the total energy efficiency of combined system is higher than 60% which is considered to be an acceptable value for a combined cycle system. Miller et al. (2012) employed a plug flow reactor for non-catalytic gasification of Spirulina algae under supercritical water gasification. They showed that the maximum rate of gasification under supercritical condition is much higher than the rate reported by previous studies.