scholarly journals Study on the Influence of Geometric Characteristics of Grain Membranes on Permeability Properties in Porous Sandstone

Membranes ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 587
Author(s):  
Run Shi ◽  
Huaiguang Xiao ◽  
Chengmeng Shao ◽  
Mingzheng Huang ◽  
Lei He
Keyword(s):  
Fluid Flow ◽  
Single Parameter ◽  
Control Group ◽  
Porous Rock ◽  
Permeability Characteristics ◽  
Natural Rock ◽  
Porous Sandstone ◽  
Novel Method ◽  
Boltzmann Method ◽  
Flow Laws

Studying the influence of grain characteristics on fluid flow in complex porous rock is one of the most important premises to reveal the permeability mechanism. Previous studies have mainly investigated the fluid flow laws in complex rock structures using an uncontrollable one single parameter of natural rock models or oversimplified control group models. In order to solve these problems, this paper proposes a novel method to reconstruct models that can independently control one single parameter of rock grain membranes based on mapping and reverse-mapping ideas. The lattice Boltzmann method is used to analyze the influence of grain parameters (grain radius, space, roundness, orientation, and model resolution) on the permeability characteristics (porosity, connectivity, permeability, flow path, and flow velocity). Results show that the grain radius and space have highly positive and negative correlations with permeability properties. The effect of grain roundness and resolution on permeability properties shows a strong regularity, while grain orientation on permeability properties shows strong randomness. This study is of great significance to reveal the fluid flow laws of natural rock structures.

scholarly journals The Effects of Periodicity Assumptions in Porous Media Modelling

2021 ◽  
Author(s):  
T. O. M. Forslund ◽  
I. A. S. Larsson ◽  
J. G. I. Hellström ◽  
T. S. Lundström
Keyword(s):  
Fluid Flow ◽  
Lattice Boltzmann ◽  
Single Unit ◽  
Unsteady Flows ◽  
Unit Cell ◽  
Porous Bed ◽  
Bed Porosity ◽  
Macroscopic Properties ◽  
Boltzmann Method ◽  
Method Model

AbstractThe effects of periodicity assumptions on the macroscopic properties of packed porous beds are evaluated using a cascaded Lattice-Boltzmann method model. The porous bed is modelled as cubic and staggered packings of mono-radii circular obstructions where the bed porosity is varied by altering the circle radii. The results for the macroscopic properties are validated using previously published results. For unsteady flows, it is found that one unit cell is not enough to represent all structures of the fluid flow which substantially impacts the permeability and dispersive properties of the porous bed. In the steady region, a single unit cell is shown to accurately represent the fluid flow across all cases studied

scholarly journals Gardnerella Vaginalis in Recurrent Urinary Tract Infection is Associated with Dysbiosis of the Bladder Microbiome

2021 ◽  
Author(s):  
Jeong-Ju Yoo ◽  
Ju Sun Song ◽  
Woong Bin Kim ◽  
Jina Yun ◽  
Hee Bong Shin ◽  
...  
Keyword(s):  
Risk Factors ◽  
Animal Experiments ◽  
Gardnerella Vaginalis ◽  
Antibiotics Resistance ◽  
Control Group ◽  
Dominant Group ◽  
E Coli ◽  
Microbiome Diversity ◽  
Causative Agents ◽  
Novel Method

Abstract Background: Recent studies on the urine microbiome have highlighted the importance of the gut-vagina-bladder axis in recurrent cystitis (RC). In particular, the role of Gardnerella as a covert pathogen that activates E. coli in animal experiments has been reported. Herein, we conducted a human bladder microbiome study to investigate the effect of Gardnerella on RC. Methods: Urine 16S ribosomal RNA gene sequencing via transurethral catheterization was conducted in the normal control group (NC) (n=18) and RC group (n=78). Results: The positive detection rate of Gardnerella species did not differ between the NC and RC groups (22.2% vs. 18.0%, p = 0.677). In addition, the Gardnerella-positive NC and Gardnerella-positive RC groups showed similar levels of microbiome diversity. The Gardnerella-positive group was categorized into three subgroups: Escherichia-dominant group, Gardnerella-dominant group, and Lactobacillus-dominant group, respectively. All of the Escherichia-dominant groups were associated with RC. Gardnerella-dominant or Lactobacillus-dominant groups expressed RC with symptoms when risk factors such as degree of Gardnerella proliferation or causative agents of bacterial vaginosis were present.Conclusion: Gardnerella can act as a covert pathogen of RC depending on other risk factors, and Gardnerella infection should be considered in patients with RC. New guideline recommendations regarding antibiotics selection based on a novel method to detect the cause of RC may be required to reduce antibiotics resistance.

scholarly journals Dynamic thiol-disulphide homeostasis in the etiopathogenesis of obstructive jaundice

2021 ◽  
Author(s):  
Fadime Gullu Haydar ◽  
Yavuz Otal ◽  
GAMZE AVCIOĞLU ◽  
Alp Şener ◽  
Selda Kidak Ozkaya ◽  
...  
Keyword(s):  
Obstructive Jaundice ◽  
Total Bilirubin ◽  
Significant Negative Correlation ◽  
Control Group ◽  
Ischemia Modified Albumin ◽  
Total Thiol ◽  
Admission Data ◽  
Novel Method ◽  
Time Of Admission ◽  
Stress Biomarker

ABSTRACT Background:Metabolic changes seen after obstructive jaundice increase the load of oxidative stress.The thiol-disulphide homeostasis (TDB) has a vital importance as oxidatice stress biomarker. Aim: The aim of present study is to investigate the dynamic thiol-disulphide homeostasis in patients diagnosed with obstructive jaundice and to compare the dynamic thiol-disulphide homeostasis with ischemia modified albumin. Study design: A total of 146 participants who were admitted to emergency department and who consisted of 69 patients and 77 healthy volunteers, were included in the study. Detailed blood samples were obtained from the patients at the time of admission. Methods: Thiol / disulphide levels were examined using a novel method developed by Erel and Neselioglu on the patients diagnosed with obstructive jaundice during the admission. Data were evaluated in computer system. Results: The levels of total thiol (p =0.025) and native thiol (p =0.023) were statistically significantly lower in the patient with obstructive jaundice than in the control group. It was observed that there was a significant negative correlation between the native thiol levels and the ALP (r =-0.262, p<0.01), urea (r =-0.313, p<0.01), total bilirubin (r =-0.388, p<0.01), direct bilirubin (r =-0.351, p<0.01) levels. At the same time, the level of disulphide (p = 0.235) was lower in the patient group than in the control group but not statistically significant. It was found that the ischemia modified albumin (IMA) values were lower in the control group than the obstructive jaundice group (p = 0.03). Conclusion: Total thiol, native thiol and IMA levels decrease in obstructive jaundice pathogenesis.

AN LBM-BASED INVESTIGATION METHOD FOR THERMAL IMMISCIBLE MIXTURE FLUID FLOW IN RECTANGULAR MULTI-JET CAVITY

2013 ◽  
Vol 28 (01) ◽  
pp. 1350198 ◽  
Author(s):  
AN-LIN WANG ◽  
RUO-FAN QIU ◽  
QIANG CHEN
Keyword(s):  
Fluid Flow ◽  
Contact Area ◽  
Multicomponent System ◽  
Mixture Flow ◽  
Investigation Method ◽  
System A ◽  
Controllable Factors ◽  
Immiscible Mixture ◽  
Boltzmann Method

An investigation method for thermal immiscible mixture fluid flow in rectangular multi-jet cavity using lattice Boltzmann method (LBM) is presented to study influence of controllable factors on quality of mixture generated from the cavity. For immiscible mixture flow, contact area of fluids has great effect on generated mixture. The basic idea is to investigate the relationship between controllable factors and contact area of key components. The contact area is obtained through numerical simulation by an improved LBM, in which temperature equation is extended to multicomponent system. A case study of thermal mixture flow in three-jet cavity using the present method is shown.

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