scholarly journals Researches on the Fast Determination of Cell Type of Cartesian Grid

2021 ◽  
Author(s):  
Xueliang Li ◽  
Lin Bi ◽  
Shuang Meng ◽  
Hongkang Liu ◽  
Tiantian Wang ◽  
...  
Keyword(s):  
High Efficiency ◽  
Complex Geometry ◽  
Grid Generation ◽  
Complex Problem ◽  
Original Method ◽  
Cartesian Grid ◽  
Immersed Boundary ◽  
Ray Casting ◽  
Cell Type

Abstract The relationship between the spatial cell and the object is unknown for the Cartesian grid using the immersed boundary method. For the researches about complex geometry or multi-body relative motion, grid generation is a very time-consuming work, and the consumption is mainly concentrated in the position determination of the Cartesian cells, which we called the cell type determination. In this study, based on the axis-aligned bounding box method and the ray casting method, we employed the dot product method and the painting algorithm to investigate the acceleration method for Cartesian grid generation. The octree structure is used to store the Cartesian cells, and the k-dimensional tree is used to store the object surface. These data management strategy can minimize the CPU’s resource while have a small memory usage. The grid generation results show that the strategy we proposed has a high efficiency and well robustness, and the time consume can reduce more than 50% compare with the original method. When dealing with a enough complex problem, the time consume can even reaches several orders of magnitude difference compared with the original method.

Rapid, parallel CFD grid generation using octrees

2013 ◽  
Vol 117 (1188) ◽  
pp. 133-146 ◽  
Author(s):  
G. J. Page
Keyword(s):  
Distributed Memory ◽  
Complex Geometry ◽  
Grid Generation ◽  
Memory Systems ◽  
Current Approach ◽  
Immersed Boundary ◽  
Flow Solver ◽  
Stl File ◽  
Eddy Simulation ◽  
Uniform Distributions

Abstract As Large Eddy Simulation is increasingly applied to flows containing complex geometry, grid generation becomes difficult and time consuming when using software originally developed for RANS flow solvers. The traditional ‘pipeline’ approach of grid generation → solve → visualise entails the time consuming transfer of large files and conversion of file formats. This work demonstrates a grid generation methodology developed specifically to be integrated with parallel LES. The current approach is to use a Cartesian grid with adaptive refinement based upon geometry intersection, surface detail and surface curvature. The grid is defined by an octree data structure with the geometry defined by triangular facets using the STL file format. The result is a set of ‘cubical’ subdomains, each with identical numbers of cells and uniform distributions within the cube. Some subdomains will be entirely fluid and can be solved using straightforward CFD techniques, whilst some cubes will be cut by the surfaces. Individual cells are then tagged as ‘solid’, ‘fluid’ or ‘cut’ with the solver expected to use an immersed boundary approach to model the surface. A key feature is the design of the algorithm to be parallelisable on both shared and distributed memory systems. The distributed memory parallel dynamically partitions the grid as it is being generated, so that the partitioning is suitable for a subsequent flow solver. Grid generation testing has been carried out on a variety of input CAD files ranging up to 350,000 facets. A landing gear case shows how the grid generator correctly finds the fluid inside of the tire and other cavities within the hub. In scalar mode, a grid with 4,916 cubes and 468 million cells is generated in less than 100 seconds, whilst in parallel on 32 processor cores this can be achieved in 4·6 seconds.

scholarly journals Correction: Facile synthesis of ultrathin Ni-MOF nanobelts for high-efficiency determination of glucose in human serum

2020 ◽  
Vol 8 (25) ◽  
pp. 5547-5548
Author(s):  
Xiao Xiao ◽  
Shasha Zheng ◽  
Xinran Li ◽  
Guangxun Zhang ◽  
Xiaotian Guo ◽  
...  
Keyword(s):  
Human Serum ◽  
High Efficiency ◽  
Facile Synthesis ◽  
Efficiency Determination

Correction for ‘Facile synthesis of ultrathin Ni-MOF nanobelts for high-efficiency determination of glucose in human serum’ by Xiao Xiao et al., J. Mater. Chem. B, 2017, 5, 5234–5239, DOI: 10.1039/C7TB00180K.

scholarly journals Wine origin authentication linked to terroir – wine fingerprint

2019 ◽  
Vol 15 ◽  
pp. 02033
Author(s):  
B. Gabel
Keyword(s):  
Pore Water ◽  
Isotope Composition ◽  
Food Product ◽  
Isotopic Signature ◽  
Original Method ◽  
Economic Problem ◽  
Red Wines ◽  
Table Grapes ◽  
Mineral Phases

Global wine and alcohol trade faces a serious economic problem linked to counterfeiting of these commodities. Recently applied authentication methods and techniques pose more difficulties for counterfeiters but they are apparently not effective once we consider economical losses identified by EU legal authorities. The presented solution links isotopic characteristics of the soil, plant, technological intermediate product and the final food product (wine, grapes) on the basis of 87Sr/86Sr isotopes ratios. For the isotopic signature of wines, the average isotope composition of the substrate cannot be a reliable indicator. Only the isotopic composition of pore water can, as it leaches various mineral phases at different stages and passes into vine root system. Instead of complicated sampling of pore water, an original method of preparing and processing soil samples and consequently must & wine samples was developed. Based on both, soil and biological material analysis, we can unquestionably determine not only geographical but also regional and local authenticity of the wine. Determination of red wines isotopic signature is more straightforward process in comparison to white wines, because of technologically different processing of grapes. That is the reason why, in case of white vines, the 87Sr/86Sr ratio of bentonites (natural purifier and absorbent useful in the process of winemaking) must also be taken into consideration. Results of analyses of Slovak wines from geographically diverse regions as well as from sites in close-by distances have clearly established reliability of presented concept, in which the soil is linked to the plant and to the final food product (wine or table grapes).

scholarly journals Isolation and characterization of pathogenic Escherichia coli bacteriophages from chicken and beef offal

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Celosia Lukman ◽  
Christopher Yonathan ◽  
Stella Magdalena ◽  
Diana Elizabeth Waturangi
Keyword(s):  
Escherichia Coli ◽  
Foodborne Pathogens ◽  
High Efficiency ◽  
Multiplicity Of Infection ◽  
Isolation And Characterization ◽  
Transmission Electron ◽  
Pathogenic Escherichia Coli ◽  
Family Based

Abstract Objective This study was conducted to isolate and characterize lytic bacteriophages for pathogenic Escherichia coli from chicken and beef offal, and analyze their capability as biocontrol for several foodborne pathogens. Methods done in this research are bacteriophage isolation, purification, titer determination, application, determination of host range and minimum multiplicity of infection (miMOI), and bacteriophage morphology. Results Six bacteriophages successfully isolated from chicken and beef offal using EPEC and EHEC as host strain. Bacteriophage titers observed between 109 and 1010 PFU mL−1. CS EPEC and BL EHEC bacteriophage showed high efficiency in reduction of EPEC or EHEC contamination in meat about 99.20% and 99.04%. The lowest miMOI was 0.01 showed by CS EPEC bacteriophage. CI EPEC and BL EPEC bacteriophage suspected as Myoviridae family based on its micrograph from Transmission Electron Microscopy (TEM). Refers to their activity, bacteriophages isolated in this study have a great potential to be used as biocontrol against several foodborne pathogens.

Research and Application of High-Efficiency Multi-Cyclone Dust Removal

2011 ◽  
Vol 109 ◽  
pp. 400-404
Author(s):  
Yan Hong Yang ◽  
Da Fu Ni
Keyword(s):  
Structural Design ◽  
High Efficiency ◽  
Dust Removal ◽  
Working Principle ◽  
Selection Of

Performance and working principle of high-efficiency multi-cyclone were analyzed, and the structural design shortage of original high-efficiency multi-cyclone was pointed out. Its structure was researched and designed, including determination of setting chamber and pipe number, selection of material and the design of cyclones.

scholarly journals Tissue-Specific Transcriptional Targeting of a Replication-Competent Retroviral Vector

2002 ◽  
Vol 76 (24) ◽  
pp. 12783-12791 ◽  
Author(s):  
Christopher R. Logg ◽  
Aki Logg ◽  
Robert J. Matusik ◽  
Bernard H. Bochner ◽  
Noriyuki Kasahara
Keyword(s):  
Tumor Cells ◽  
Viral Vectors ◽  
High Efficiency ◽  
Leukemia Virus ◽  
Transduction Efficiency ◽  
Promoter Strength ◽  
Cell Type ◽  
Cell Type Specificity ◽  
Tissue Specific

ABSTRACT The inability of replication-defective viral vectors to efficiently transduce tumor cells in vivo has prevented the successful application of such vectors in gene therapy of cancer. To address the need for more efficient gene delivery systems, we have developed replication-competent retroviral (RCR) vectors based on murine leukemia virus (MLV). We have previously shown that such vectors are capable of transducing solid tumors in vivo with very high efficiency. While the natural requirement of MLV infection for cell division imparts a certain degree of specificity for tumor cells, additional means for confining RCR vector replication to tumor cells are desirable. Here, we investigated the parameters critical for successful tissue-specific transcriptional control of RCR vector replication by replacing various lengths of the MLV enhancer/promoter with sequences derived either from the highly prostate-specific probasin (PB) promoter or from a more potent synthetic variant of the PB promoter. We assessed the transcriptional specificity of the resulting hybrid long terminal repeats (LTRs) and the cell type specificity and efficiency of replication of vectors containing these LTRs. Incorporation of PB promoter sequences effectively restricted transcription from the LTR to prostate-derived cells and imparted prostate-specific RCR vector replication but required the stronger synthetic promoter and retention of native MLV sequences in the vicinity of the TATA box for optimal replicative efficiency and specificity. Our results have thus identified promoter strength and positioning within the LTR as important determinants for achieving both high transduction efficiency and strict cell type specificity in transcriptionally targeted RCR vectors.

A Hybrid Highly Parallelizable Algorithm for the Dynamics of Rigid Body Chain Systems

1999 ◽  
Author(s):  
Shanzhong Duan ◽  
Kurt S. Anderson
Keyword(s):  
Rigid Body ◽  
Degrees Of Freedom ◽  
High Efficiency ◽  
Equations Of Motion ◽  
Constraint Forces ◽  
Dynamics Of Rigid Body ◽  
A Chain ◽  
Explicit Determination ◽  
Order Algorithm

Abstract The paper presents a new hybrid parallelizable low order algorithm for modeling the dynamic behavior of multi-rigid-body chain systems. The method is based on cutting certain system interbody joints so that largely independent multibody subchain systems are formed. These subchains interact with one another through associated unknown constraint forces f¯c at the cut joints. The increased parallelism is obtainable through cutting the joints and the explicit determination of associated constraint loads combined with a sequential O(n) procedure. In other words, sequential O(n) procedures are performed to form and solve equations of motion within subchains and parallel strategies are used to form and solve constraint equations between subchains in parallel. The algorithm can easily accommodate the available number of processors while maintaining high efficiency. An O[(n+m)Np+m(1+γ)Np+mγlog2Np](0<γ<1) performance will be achieved with Np processors for a chain system with n degrees of freedom and m constraints due to cutting of interbody joints.

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