A run time combustion zoning technique towards the EDC approach in large-scale CFD simulations

Purpose – This paper aims to present a novel run time combustion zoning (RTCZ) technique based on the working principle of eddy dissipation concept (EDC) for combustion modeling. This technique selectively chooses cells in which the full reaction mechanism needs to be solved. The selection criterion is based on the concept of differentiating between combustion and the non-combustion zone. With this approach, considerable reduction in computational load and stability of the solution was observed and even the number of iterations required to achieve a stable solution was significantly reduced. Design/methodology/approach – Computational fluid dynamics (CFD) simulations of real life combustion problems such as industrial scale flares, fuel fired furnaces and IC engines are difficult due to the strong interactions of chemistry with turbulence as well as the wide range distribution of time and length scales. In addition, comprehensive chemical mechanisms for hydrocarbon combustion may include hundreds of species and thousands of reactions that are known in detail for only a limited number of fuels. Even with the most advanced computers, accurate simulation of these problems is not easy. Hence, the modeler needs to have strategies to either simplify the chemistry or to improve the computational efficiency. Findings – The EDC turbulence model has been widely used for treating the interaction between turbulence and the chemistry in combustion problems. In an EDC model, combustion is assumed to occur in a constant pressure reactor, with initial conditions taken as the concentration of the current species and temperature in the cell. With these assumptions, EDC solves the full or simplified reaction mechanism in all the grid cells at all iterations. Originality/value – This paper presents a novel RTCZ technique for improving the computational efficiency, when the EDC model is used in CFD modeling. Considerable reduction in computational time and stability of the solution can be achieved. It was also observed that the number of iterations required to achieve a converged solution was significantly reduced.

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A new reduced model for the moments of droplet size distribution in condensing flow

International Journal of Numerical Methods for Heat &amp Fluid Flow ◽

10.1108/hff-04-2013-0136 ◽

2015 ◽

Vol 25 (2) ◽

pp. 320-332 ◽

Cited By ~ 5

Author(s):

Xiaoke Ku ◽

Rob Hagmeijer

Keyword(s):

Size Distribution ◽

Droplet Size ◽

Computational Cost ◽

Droplet Size Distribution ◽

Reduced Model ◽

Computational Time ◽

Content Type ◽

Practical Applications ◽

Pulse Experiment ◽

Wide Range

Purpose – The purpose of this paper is to create a computationally efficient reduced model (RM) for the moments of droplet size distribution (DSD) in condensing flow. Design/methodology/approach – The kinetic equation (KE) exactly describes the time dependence of the DSD and can be regarded as the most rigorous representation of a system with condensation. Because of the typical wide range in droplet size, the KE requires excessive computational time and is not attractive for most practical applications. To reduce the overall computational efforts, a novel set of moment equations, derived from the KE has been proposed. Findings – To demonstrate the simplicity and accuracy of the model, the authors employ a typical nucleation pulse experiment for which benchmark KE-solutions have also been computed. Comparison of predicted moments from both the RM and the KE approach reveals that the RM is capable of capturing the evolving feature of moments with reasonable accuracy. Originality/value – The authors have created a novel reduced method for numerical computations of the lower-order moments of the DSD in condensing flow. Unlike the typical method of moments, the RM eliminates the need for assumptions on the shape of the distribution function and could estimate the moments at very low computational cost.

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Scaling computational genomics to millions of individuals with GPUs

10.1101/470138 ◽

2018 ◽

Author(s):

Amaro Taylor-Weiner ◽

François Aguet ◽

Nicholas J. Haradhvala ◽

Sager Gosai ◽

Shankara Anand ◽

...

Keyword(s):

Machine Learning ◽

Qtl Mapping ◽

Computational Efficiency ◽

Matrix Factorization ◽

Hypothesis Generation ◽

Computational Genomics ◽

Biomedical Science ◽

Wide Range ◽

Run Time ◽

Non Negative Matrix Factorization

AbstractCurrent genomics methods were designed to handle tens to thousands of samples, but will soon need to scale to millions to keep up with the pace of data and hypothesis generation in biomedical science. Moreover, costs associated with processing these growing datasets will become prohibitive without improving the computational efficiency and scalability of methods. Here, we show that recently developed machine-learning libraries (TensorFlow and PyTorch) facilitate implementation of genomics methods for GPUs and significantly accelerate computations. To demonstrate this, we re-implemented methods for two commonly performed computational genomics tasks: QTL mapping and Bayesian non-negative matrix factorization. Our implementations ran > 200 times faster than current CPU-based versions, and these analyses are ∼5-10 fold cheaper on GPUs due to the vastly shorter runtimes. We anticipate that the accessibility of these libraries, and the improvements in run-time will lead to a transition to GPU-based implementations for a wide range of computational genomics methods.

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Arylation of enelactams using TIPSOTf: reaction scope and mechanistic insight

Organic Chemistry Frontiers ◽

10.1039/d0qo01396j ◽

2021 ◽

Author(s):

Tomasz J. Idzik ◽

Zofia M. Myk ◽

Łukasz Struk ◽

Magdalena Perużyńska ◽

Gabriela Maciejewska ◽

...

Keyword(s):

Reaction Mechanism ◽

Multinuclear Nmr ◽

Mechanistic Insight ◽

Nmr Study ◽

Wide Range

Triisopropylsilyltrifluoromethanesulfonate can be effectively used for the arylation of a wide range of enelactams. The multinuclear NMR study provided deep insights into the reaction mechanism.

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Ligand-Enabled γ-C(sp3)–H Olefination of Free Carboxylic Acids

10.26434/chemrxiv.11857857 ◽

2020 ◽

Author(s):

Kiron Kumar Ghosh ◽

Alexander Uttry ◽

Francesca Ghiringhelli ◽

Arup Mondal ◽

Manuel van Gemmeren

Keyword(s):

Reaction Mechanism ◽

Carboxylic Acids ◽

Michael Addition ◽

Kinetic Studies ◽

Wide Range ◽

Palladium Catalyzed

We report the ligand enabled C(sp3)–H activation/olefination of free carboxylic acids in the γ-position. Through an intramolecular Michael-addition, δ-lactones are obtained as products. Two distinct ligand classes are identified that enable the challenging palladium-catalyzed activation of free carboxylic acids in the γ-position. The developed protocol features a wide range of acid substrates and olefin reaction partners and is shown to be applicable on a preparatively useful scale. Insights into the underlying reaction mechanism obtained through kinetic studies are reported.<br>

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Transfer of Plasmid DNA to Clinical Coagulase-Negative Staphylococcal Pathogens by Using a Unique Bacteriophage

Applied and Environmental Microbiology ◽

10.1128/aem.04190-14 ◽

2015 ◽

Vol 81 (7) ◽

pp. 2481-2488 ◽

Cited By ~ 19

Author(s):

Volker Winstel ◽

Petra Kühner ◽

Bernhard Krismer ◽

Andreas Peschel ◽

Holger Rohde

Keyword(s):

Plasmid Dna ◽

Genetic Manipulation ◽

Current Knowledge ◽

Virulence Determinants ◽

Coagulase Negative Staphylococci ◽

Reliable Technique ◽

Content Type ◽

Research Activities ◽

Wide Range ◽

Genetic Barriers

ABSTRACTGenetic manipulation of emerging bacterial pathogens, such as coagulase-negative staphylococci (CoNS), is a major hurdle in clinical and basic microbiological research. Strong genetic barriers, such as restriction modification systems or clustered regularly interspaced short palindromic repeats (CRISPR), usually interfere with available techniques for DNA transformation and therefore complicate manipulation of CoNS or render it impossible. Thus, current knowledge of pathogenicity and virulence determinants of CoNS is very limited. Here, a rapid, efficient, and highly reliable technique is presented to transfer plasmid DNA essential for genetic engineering to important CoNS pathogens from a uniqueStaphylococcus aureusstrain via a specificS. aureusbacteriophage, Φ187. Even strains refractory to electroporation can be transduced by this technique once donor and recipient strains share similar Φ187 receptor properties. As a proof of principle, this technique was used to delete the alternative transcription factor sigma B (SigB) via allelic replacement in nasal and clinicalStaphylococcus epidermidisisolates at high efficiencies. The described approach will allow the genetic manipulation of a wide range of CoNS pathogens and might inspire research activities to manipulate other important pathogens in a similar fashion.

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Use of Proteins Identified through a Functional Genomic Screen To Develop a Protein Subunit Vaccine That Provides Significant Protection against Virulent Streptococcus suis in Pigs

Infection and Immunity ◽

10.1128/iai.00559-17 ◽

2017 ◽

Vol 86 (3) ◽

Cited By ~ 3

Author(s):

Susan L. Brockmeier ◽

Crystal L. Loving ◽

Tracy L. Nicholson ◽

Jinhong Wang ◽

Sarah E. Peters ◽

...

Keyword(s):

Immune Response ◽

Vaccine Trial ◽

Streptococcus Suis ◽

Protein Subunit ◽

Content Type ◽

Degree Of Protection ◽

Wide Range ◽

Associated Proteins ◽

Clinical Protection ◽

Cellular Immune

ABSTRACT Streptococcus suis is a bacterium that is commonly carried in the respiratory tract and that is also one of the most important invasive pathogens of swine, commonly causing meningitis, arthritis, and septicemia. Due to the existence of many serotypes and a wide range of immune evasion capabilities, efficacious vaccines are not readily available. The selection of S. suis protein candidates for inclusion in a vaccine was accomplished by identifying fitness genes through a functional genomics screen and selecting conserved predicted surface-associated proteins. Five candidate proteins were selected for evaluation in a vaccine trial and administered both intranasally and intramuscularly with one of two different adjuvant formulations. Clinical protection was evaluated by subsequent intranasal challenge with virulent S. suis . While subunit vaccination with the S. suis proteins induced IgG antibodies to each individual protein and a cellular immune response to the pool of proteins and provided substantial protection from challenge with virulent S. suis , the immune response elicited and the degree of protection were dependent on the parenteral adjuvant given. Subunit vaccination induced IgG reactive against different S. suis serotypes, indicating a potential for cross protection.

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A Termination Criterion for Probabilistic Point Clouds Registration

Signals ◽

10.3390/signals2020013 ◽

2021 ◽

Vol 2 (2) ◽

pp. 159-173

Author(s):

Simone Fontana ◽

Domenico Giorgio Sorrenti

Keyword(s):

State Of The Art ◽

Point Clouds ◽

Computational Time ◽

Termination Criteria ◽

Practical Usefulness ◽

Local Point ◽

Termination Criterion ◽

Probabilistic Point ◽

Excessive Number ◽

Number Of Iterations

Probabilistic Point Clouds Registration (PPCR) is an algorithm that, in its multi-iteration version, outperformed state-of-the-art algorithms for local point clouds registration. However, its performances have been tested using a fixed high number of iterations. To be of practical usefulness, we think that the algorithm should decide by itself when to stop, on one hand to avoid an excessive number of iterations and waste computational time, on the other to avoid getting a sub-optimal registration. With this work, we compare different termination criteria on several datasets, and prove that the chosen one produces very good results that are comparable to those obtained using a very large number of iterations, while saving computational time.

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The role of organizational culture in the knowledge management process

Journal of Knowledge Management ◽

10.1108/jkm-08-2014-0353 ◽

2015 ◽

Vol 19 (3) ◽

pp. 433-455 ◽

Cited By ~ 70

Author(s):

Christina Ling-hsing Chang ◽

Tung-Ching Lin

Keyword(s):

Organizational Culture ◽

Knowledge Management ◽

Customer Service ◽

Survey Methodology ◽

Cultural Dimensions ◽

Content Type ◽

Knowledge Resources ◽

Positive Effects ◽

Wide Range ◽

The Individual

Purpose – The purpose of the study is to focus on the enhancement of knowledge management (KM) performance and the relationship between organizational culture and KM process intention of individuals because of the diversity of organizational cultures (which include results-oriented, tightly controlled, job-oriented, closed system and professional-oriented cultures). Knowledge is a primary resource in organizations. If firms are able to effectively manage their knowledge resources, then a wide range of benefits can be reaped such as improved corporate efficiency, effectiveness, innovation and customer service. Design/methodology/approach – The survey methodology, which has the ability to enhance generalization of results (Dooley, 2001), was used to collect the data utilized in the testing of the research hypotheses. Findings – Results- and job-oriented cultures have positive effects on employee intention in the KM process (creation, storage, transfer and application), whereas a tightly controlled culture has negative effects. Research limitations/implications – However, it would have been better to use a longitudinal study to collect useful long-term data to understand how the KM process would be influenced when organizational culture dimensions are changed through/by management. This is the first limitation of this study. According to Mason and Pauleen (2003), KM culture is a powerful predictor of individual knowledge-sharing behavior, which is not included in this study. Thus, this is the second limitation of this paper. Moreover, national culture could be an important issue in the KM process (Jacks et al., 2012), which is the third limitation of this paper for not comprising it. Practical implications – In researchers’ point of view, results- and job-oriented cultures have positive effects, whereas a tightly controlled culture has a negative effect on the KM process intention of the individual. These findings provide evidences that challenge the perspective of Kayworth and Leidner (2003) on this issue. As for practitioners, management has a direction to modify their organizational culture to improve the performance of KM process. Social implications – Both behavioral and value perspectives of the organizational cultural dimensions (results-oriented, tightly control, job-oriented, sociability, solidarity, need for achievement and democracy) should be examined to ascertain their effects firstly on KM culture and then on the KM process intention of the individual. It is hoped that the current study will spawn future investigations that lead to the development of an integrated model which includes organizational culture, KM culture and the KM process intention of the individual. Originality/value – The results-oriented, loosely controlled and job-oriented cultures will improve the effectiveness of the KM process and will also increase employees’ satisfaction and willingness to stay with the organization.

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From digital citizen to digital professional

Kybernetes ◽

10.1108/k-07-2018-0390 ◽

2019 ◽

Vol 48 (7) ◽

pp. 1463-1477

Author(s):

Olga Marino ◽

Jaime Andres Gutierrez ◽

Sandra Aguirre

Keyword(s):

Information And Communication Technologies ◽

Communication Technologies ◽

Cutting Edge ◽

Case Study Methodology ◽

Content Type ◽

Innovative Strategy ◽

Global Issues ◽

Wide Range ◽

Information And Communication ◽

Teaching Learning

Purpose This paper aims to propose and evaluate a pedagogically sound and innovative strategy to teach a higher education course that prepares future professionals to intelligently use information and communication technologies (ICTs) in their personal and professional lives. Design/methodology/approach The conceptual framework used for the design of the course was the socio-constructivism and activity theories. The implementation of the course was evaluated using the intrinsic case study methodology by including several instruments. Findings The pedagogical strategy proposed proved to be sound, as the evaluation showed that students were able to describe, use and propose innovative uses of a wide range of cutting-edge technologies in their both everyday lives and professional settings; they also had the skills to analyse the opportunities and challenges that these presented. Moreover, students liked this innovative way of learning and ended with a positive attitude towards ICT. Originality/value Although several courses prepare students to be digital citizens or use ICT to enhance the teaching-learning process, millennials are ill prepared to use cutting-edge technologies in an innovative, responsible and critical way in their future professions. The course that was designed is original in that it goes beyond preparing digital citizens to prepare professionals in any domain to use ICT in an informed and responsible way. Moreover, it is a documented, successful example of an undergraduate universal course in a highly important current society dimension. The authors believe that its pedagogical proposal could be transferred to courses dealing with other global issues such as the environment, economy and peace.

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Incompressible smoothed particle hydrodynamics for MHD double-diffusive natural convection of a nanofluid in a cavity containing an oscillating pipe

International Journal of Numerical Methods for Heat &amp Fluid Flow ◽

10.1108/hff-06-2019-0461 ◽

2019 ◽

Vol 30 (2) ◽

pp. 882-917 ◽

Cited By ~ 4

Author(s):

Abdelraheem M. Aly

Keyword(s):

Natural Convection ◽

Smoothed Particle Hydrodynamics ◽

Cavity Wall ◽

Lagrangian Description ◽

Content Type ◽

Wide Range ◽

Particle Hydrodynamics ◽

Smoothed Particle ◽

Incompressible Smoothed Particle Hydrodynamics ◽

Double Diffusive

Purpose This paper aims to adopt incompressible smoothed particle hydrodynamics (ISPH) method to simulate MHD double-diffusive natural convection in a cavity containing an oscillating pipe and filled with nanofluid. Design/methodology/approach The Lagrangian description of the governing partial differential equations are solved numerically using improved ISPH method. The inner oscillating pipe is divided into two different pipes as an open and a closed pipe. The sidewalls of the cavity are cooled with a lower concentration C_c and the horizontal walls are adiabatic. The inner pipe is heated with higher concentration C_h. The analysis has been conducted for the two different cases of inner oscillating pipes under the effects of wide range of governing parameters. Findings It is found that a suitable oscillating pipe makes a well convective transport inside a cavity. Presence of the oscillating pipe has effects on the heat and mass transfer and fluid intensity inside a cavity. Hartman parameter suppresses the velocity and weakens the maximum values of the stream function. An increase on Hartman, Lewis and solid volume fraction parameters leads to an increase on average Nusselt number on an oscillating pipe and left cavity wall. Average Sherwood number on an oscillating pipe and left cavity wall decreases as Hartman parameter increases. Originality/value The main objective of this work is to study the MHD double-diffusive natural convection of a nanofluid in a square cavity containing an oscillating pipe using improved ISPH method.

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