The Experts below are selected from a list of 123159 Experts worldwide ranked by ideXlab platform
Jianchao Cai - One of the best experts on this subject based on the ideXlab platform.
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a simulation method for permeability of porous media based on multiple fractal model
International Journal of Engineering Science, 2015Co-Authors: Xiaohua Tan, Jianyi Liu, Liehui Zhang, Jianchao CaiAbstract:Abstract Fluid flow in fractal porous media is a ubiquitous Natural Phenomenon which has received much attention over three decades in a wide variety of fields. In order to find a relationship between the pore of distribution and the permeability of porous media, a simulation method for the permeability of porous media is proposed based on the multiple fractal model. The pore size distributions and the permeabilities of the porous medium simulated by the presented method are compared with available experimental data. The validity of simulation method is obtained by the good agreement between the simulated results and the experimental data.
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generalized modeling of spontaneous imbibition based on hagen poiseuille flow in tortuous capillaries with variably shaped apertures
Langmuir, 2014Co-Authors: Jianchao Cai, Edmund Perfect, Chulin ChengAbstract:Spontaneous imbibition of wetting liquids in porous media is a ubiquitous Natural Phenomenon which has received much attention in a wide variety of fields over several decades. Many traditional and recently presented capillary-driven flow models are derived based on Hagen–Poiseuille (H–P) flow in cylindrical capillaries. However, some limitations of these models have motivated modifications by taking into account different geometrical factors. In this work, a more generalized spontaneous imbibition model is developed by considering the different sizes and shapes of pores, the tortuosity of imbibition streamlines in random porous media, and the initial wetting-phase saturation. The interrelationships of accumulated imbibition weight, imbibition rate and gas recovery and the properties of the porous media, wetting liquids, and their interactions are derived analytically. A theoretical analysis and comparison denote that the presented equations can generalize several traditional and newly developed models fr...
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prediction of effective permeability in porous media based on spontaneous imbibition effect
International Journal of Modern Physics C, 2012Co-Authors: Jianchao Cai, Lijun You, Jing Wang, Ronghua PengAbstract:Permeability is an important parameter for characterizing the transport properties (e.g. heat and mass transfer) of porous media. It is one of the crucial issues that the permeability of porous media is exactly and quickly decided in many fields such as reservoir engineering, groundwater engineering and composite material modeling. Spontaneous imbibition is a fundamental and ubiquitous Natural Phenomenon extensively existing in a variety of processes. In this paper, the relationships between the height and weight of imbibition versus the time are derived based on Darcy's law, and a simple method for predicting effective permeability of porous media using spontaneous imbibition effect is proposed, including expressions for permeabilities of artificial and Natural porous media. The validity of the proposed models is analysed and tested by experimental data.
Vivek Patel - One of the best experts on this subject based on the ideXlab platform.
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multi objective optimization of heat exchangers using a modified teaching learning based optimization algorithm
Applied Mathematical Modelling, 2013Co-Authors: Venkata R Rao, Vivek PatelAbstract:Abstract Teaching-learning-based optimization (TLBO) is a recently developed heuristic algorithm based on the Natural Phenomenon of teaching-learning process. In the present work, a modified version of the TLBO algorithm is introduced and applied for the multi-objective optimization of heat exchangers. Plate-fin heat exchanger and shell and tube heat exchanger are considered for the optimization. Maximization of heat exchanger effectiveness and minimization of total cost of the exchanger are considered as the objective functions. Two examples are presented to demonstrate the effectiveness and accuracy of the proposed algorithm. The results of optimization using the modified TLBO are validated by comparing with those obtained by using the genetic algorithm (GA).
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multi objective optimization of two stage thermoelectric cooler using a modified teaching learning based optimization algorithm
Engineering Applications of Artificial Intelligence, 2013Co-Authors: Venkata R Rao, Vivek PatelAbstract:Teaching-learning-based optimization (TLBO) is a recently developed heuristic algorithm based on the Natural Phenomenon of teaching-learning process. In the present work, a modified version of the TLBO algorithm is introduced and applied for the multi-objective optimization of a two stage thermoelectric cooler (TEC). Two different arrangements of the thermoelectric cooler are considered for the optimization. Maximization of cooling capacity and coefficient of performance of the thermoelectric cooler are considered as the objective functions. An example is presented to demonstrate the effectiveness and accuracy of the proposed algorithm. The results of optimization obtained by using the modified TLBO are validated by comparing with those obtained by using the basic TLBO, genetic algorithm (GA), particle swarm optimization (PSO) and artificial bee colony (ABC) algorithms.
Venkata R Rao - One of the best experts on this subject based on the ideXlab platform.
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multi objective optimization of heat exchangers using a modified teaching learning based optimization algorithm
Applied Mathematical Modelling, 2013Co-Authors: Venkata R Rao, Vivek PatelAbstract:Abstract Teaching-learning-based optimization (TLBO) is a recently developed heuristic algorithm based on the Natural Phenomenon of teaching-learning process. In the present work, a modified version of the TLBO algorithm is introduced and applied for the multi-objective optimization of heat exchangers. Plate-fin heat exchanger and shell and tube heat exchanger are considered for the optimization. Maximization of heat exchanger effectiveness and minimization of total cost of the exchanger are considered as the objective functions. Two examples are presented to demonstrate the effectiveness and accuracy of the proposed algorithm. The results of optimization using the modified TLBO are validated by comparing with those obtained by using the genetic algorithm (GA).
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multi objective optimization of two stage thermoelectric cooler using a modified teaching learning based optimization algorithm
Engineering Applications of Artificial Intelligence, 2013Co-Authors: Venkata R Rao, Vivek PatelAbstract:Teaching-learning-based optimization (TLBO) is a recently developed heuristic algorithm based on the Natural Phenomenon of teaching-learning process. In the present work, a modified version of the TLBO algorithm is introduced and applied for the multi-objective optimization of a two stage thermoelectric cooler (TEC). Two different arrangements of the thermoelectric cooler are considered for the optimization. Maximization of cooling capacity and coefficient of performance of the thermoelectric cooler are considered as the objective functions. An example is presented to demonstrate the effectiveness and accuracy of the proposed algorithm. The results of optimization obtained by using the modified TLBO are validated by comparing with those obtained by using the basic TLBO, genetic algorithm (GA), particle swarm optimization (PSO) and artificial bee colony (ABC) algorithms.
Margret Engelhard - One of the best experts on this subject based on the ideXlab platform.
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synthetic gene drive between continuity and novelty crucial differences between gene drive and genetically modified organisms require an adapted risk assessment for their use
EMBO Reports, 2018Co-Authors: Samson Simon, Mathias Otto, Margret EngelhardAbstract:CRISPR/Cas accelerates the development of synthetic gene drive organisms to quickly spread a genetic modification among the target species. Both in academia and politics, the use of CRISPR/Cas gene drive to potentially control disease vectors, plant pests or invasive alien species is controversial, as exemplified by the last Conference of the Parties of the United Nations Convention on Biodiversity (CBD) and the most recent meeting of its scientific expert group on synthetic biology (Ad Hoc Technical Expert Group/AHTEG). While some argue that current risk assessment frameworks can accommodate synthetic gene drives, others call for a moratorium owing to gene drives’ potentially detrimental impact on wildlife. In essence, the question is whether we have sufficient experience and knowledge to handle this technology safely. Experience and knowledge in turn depend on the degree of continuity and novelty of synthetic gene drive organisms (GDO), compared to existing genetically modified organisms (GMO). While gene drives exist in nature, we find that GDO differ from the currently released GMO on five levels. A clear understanding and analysis of these differences is crucial for any risk assessment regime and a socially acceptable and ethical evaluation that is vital for the application of this technology. ### From nature to synthetic biology Gene drive is a Natural Phenomenon by which a genetic element is transferred to more than 50% of the offspring of a sexually reproducing organism: Natural gene drives are selfish genetic elements that sidestep the rules of Mendelian inheritance, resulting in a so‐called super‐Mendelian inheritance. In 2003, Austin Burt proposed to use this Natural Phenomenon and synthetically engineer gene drives using specific enzymes called “homing endonucleases.” The discovery of the Natural bacterial defence system CRISPR/Cas and its application as a highly specific nuclease eventually boosted the development of synthetic gene drives to circumvent Mendelian inheritance of both the gene drive elements itself …
Chulin Cheng - One of the best experts on this subject based on the ideXlab platform.
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generalized modeling of spontaneous imbibition based on hagen poiseuille flow in tortuous capillaries with variably shaped apertures
Langmuir, 2014Co-Authors: Jianchao Cai, Edmund Perfect, Chulin ChengAbstract:Spontaneous imbibition of wetting liquids in porous media is a ubiquitous Natural Phenomenon which has received much attention in a wide variety of fields over several decades. Many traditional and recently presented capillary-driven flow models are derived based on Hagen–Poiseuille (H–P) flow in cylindrical capillaries. However, some limitations of these models have motivated modifications by taking into account different geometrical factors. In this work, a more generalized spontaneous imbibition model is developed by considering the different sizes and shapes of pores, the tortuosity of imbibition streamlines in random porous media, and the initial wetting-phase saturation. The interrelationships of accumulated imbibition weight, imbibition rate and gas recovery and the properties of the porous media, wetting liquids, and their interactions are derived analytically. A theoretical analysis and comparison denote that the presented equations can generalize several traditional and newly developed models fr...
