Evaluation of the mixing quality of high-viscosity yield stress fluids in a tubular reactor

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Le Xie ◽  
Guangwen He ◽  
Bin Yu ◽  
Shaowei Yan
Keyword(s):  
Yield Stress ◽  
Large Scale ◽  
Molecular Diffusion ◽  
Time History ◽  
High Viscosity ◽  
Cfd Model ◽  
Step Method ◽  
Mean Velocity ◽  
Mixing Quality

Abstract In this study, the mixing quality of high-viscosity yield stress fluid (Carbopol aqueous solution) under laminar and turbulent flow regimes was evaluated through a numerical experimental study. A three-dimensional computational fluid dynamics large-eddy simulation (CFD-LES) model was employed to capture large-scale vortex structures. The proposed CFD model was validated by the experimental data in terms of mean velocity profiles and velocity-time history. Thereafter, the CFD model was applied to simulate the residence time distribution using the tracking technique: tracer pulse method and step method. In addition, the non-ideal flow phenomena caused by molecular diffusion and eddy diffusion were evaluated. The effects of the rheological properties on the mixing performance were also investigated. The presented results can provide useful guidance to enhance mass transfer in reactors with high-viscosity fluids.

Numerical Investigation of Multi-Scale Mixing in Microchannel T-Junction With Wavy Structure

2012 ◽  
Author(s):  
Nita Solehati ◽  
Joonsoo Bae ◽  
Agus Pulung Sasmito
Keyword(s):  
Schmidt Number ◽  
Molecular Diffusion ◽  
Chaotic Mixing ◽  
Small Scale ◽  
Transport Mechanisms ◽  
Huge Amount ◽  
Multi Scale ◽  
Wavy Structure ◽  
Mixing Quality

Mixing in chemical microreactors is a multi-scale processes as the transport mechanisms occur at different length scales. The small scale mixing depends mainly on molecular diffusion which causes conventional microchannel T-junction has poor mixing quality. To improve the quality, one can utilize secondary flow generated by wavy structure to enhance chaotic mixing. To gain better understanding of the interplay of transport mechanism, we develop numerical model for mixing in micro-channel T-junction with wavy structure. To ensure robust and accurate solutions, several discretization methods and mesh sizes were tested and compared. It is found that the solutions are sensitive to the Reynolds; huge amount of mesh (>107) is required to resolve small molecular diffusion and chaotic mixing especially at high Schmidt number, whilst relatively lesser mesh is found to be sufficient for conventional T-junction. Further, parallelization is found to be beneficial to expedite the computation, albeit the speed is not linear with the number of the processors. The mixing quality of T-junction with wavy structure is then compared with that of conventional T-junction counterpart. It is noted that up to 50% improvement of mixing quality is achieved with wavy structure which has potential for several applications.

Improving grain yield, stress resilience and quality of bread wheat using large-scale genomics

2019 ◽  
Vol 51 (10) ◽  
pp. 1530-1539 ◽  
Author(s):  
Philomin Juliana ◽  
Jesse Poland ◽  
Julio Huerta-Espino ◽  
Sandesh Shrestha ◽  
José Crossa ◽  
...  
Keyword(s):  
Grain Yield ◽  
Yield Stress ◽  
Bread Wheat ◽  
Large Scale ◽  
Stress Resilience

scholarly journals Dynamic Simulation on Deflagration of LNG Spill

2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Biao Sun ◽  
Kaihua Guo ◽  
Vishnu K. Pareek
Keyword(s):  
Large Scale ◽  
Volume Fraction ◽  
Fire Hazard ◽  
Time History ◽  
Flame Velocity ◽  
Cfd Model ◽  
Time Step ◽  
Mixing Ratios ◽  
Flame Development ◽  
The One

The deflagration characteristics of premixed LNG vapour-air mixtures with different mixing ratios were quantitatively and qualitatively investigated by using CFD (computational fluid dynamics) method. The CFD model was initially established based on theoretical analysis and then validated by a lab-scale deflagration experiment. The flame propagation behaviour, pressure-time history, and flame speed were compared with the experimental data, upon which a good agreement was achieved. A large-scale deflagration fire during LNG bunkering process was conducted using the model to investigate the flame development and overpressure effects. Mesh independence and time scale were tested in order to obtain the suitable grid resolution and time step. Deflagration cases with two different LNG vapour volume fractions, i.e., 10.4% and 15.0%, were simulated and compared. The one with a volume fraction of 10.4% which was around stoichiometric mixing ratio had the highest flame propagating speed. High flame velocity observed in the simulation was coupled with the thin flame front where overpressure occurred. The CFD model could capture the main features of deflagration combustion and account for LNG fire hazard which could provide an in-depth insight when dealing with complicated cases.

Assessment of quality of life in patients with the effects of transient ischemic stroke

2016 ◽  
pp. 37-39
Author(s):  
A. Babirad
Keyword(s):  
Quality Of Life ◽  
Ischemic Stroke ◽  
Large Scale ◽  
Cerebrovascular Diseases ◽  
Control Measures ◽  
Sociological Research ◽  
Cerebrovascular Events ◽  
Sf 36 ◽  
Angioplasty And Stenting

Cerebrovascular diseases are a problem of the world today, and according to the forecast, the problem of the near future arises. The main risk factors for the development of ischemic disorders of the cerebral circulation include oblique and aging, arterial hypertension, smoking, diabetes mellitus and heart disease. An effective strategy for the prevention of cerebrovascular events is based on the implementation of large-scale risk control measures, including the use of antiagregant and anticoagulant therapy, invasive interventions such as atheromectomy, angioplasty and stenting. In this connection, the efforts of neurologists, cardiologists, angiosurgery, endocrinologists and other specialists are the basis for achieving an acceptable clinical outcome. A review of the SF-36 method for assessing the quality of life in patients with the effects of transient ischemic stroke is presented. The assessment of quality of life is recognized in world medical practice and research, an indicator that is also used to assess the quality of the health system and in general sociological research.

Model and Method for Contributor’s Quality Assessment in Community Image Tagging Systems

2018 ◽  
pp. 45-51
Author(s):  
A. V. Ponomarev
Keyword(s):  
Large Scale ◽  
Wide Spectrum ◽  
Preference Relation ◽  
Pairwise Comparison ◽  
Ground Truth ◽  
Comparison Method ◽  
Characteristic Matrix ◽  
Image Tagging ◽  
Proposed Model

Introduction: Large-scale human-computer systems involving people of various skills and motivation into the information processing process are currently used in a wide spectrum of applications. An acute problem in such systems is assessing the expected quality of each contributor; for example, in order to penalize incompetent or inaccurate ones and to promote diligent ones.Purpose: To develop a method of assessing the expected contributor’s quality in community tagging systems. This method should only use generally unreliable and incomplete information provided by contributors (with ground truth tags unknown).Results:A mathematical model is proposed for community image tagging (including the model of a contributor), along with a method of assessing the expected contributor’s quality. The method is based on comparing tag sets provided by different contributors for the same images, being a modification of pairwise comparison method with preference relation replaced by a special domination characteristic. Expected contributors’ quality is evaluated as a positive eigenvector of a pairwise domination characteristic matrix. Community tagging simulation has confirmed that the proposed method allows you to adequately estimate the expected quality of community tagging system contributors (provided that the contributors' behavior fits the proposed model).Practical relevance: The obtained results can be used in the development of systems based on coordinated efforts of community (primarily, community tagging systems). 

Translation and Validation of the Thai Version of the Wisconsin Quality of Life Questionnaire (TH WISQoL) for Kidney Stone Patients

2020 ◽  
Vol 103 (11) ◽  
pp. 1194-1199
Keyword(s):  
Quality Of Life ◽  
Internal Consistency ◽  
Kidney Stone ◽  
Convergent Validity ◽  
Large Scale ◽  
Short Form ◽  
Outcome Measurement ◽  
Life Questionnaire ◽  
Sf 36

Objective: To develop and validate a Thai version of the Wisconsin Quality of Life (TH WISQoL) Questionnaire. Materials and Methods: The authors developed the TH WISQoL Questionnaire based on a standard multi-step process. Subsequently, the authors recruited patients with kidney stone and requested them to complete the TH WISQoL and a validated Thai version of the 36-Item Short Form Survey (TH SF-36). The authors calculated the internal consistency and interdomain correlation of TH WISQoL and compared the convergent validity between the two instruments. Results: Thirty kidney stone patients completed the TH WISQoL and the TH SF-36. The TH WISQoL showed acceptable internal consistency for all domains (Cronbach’s alpha 0.768 to 0.909). Interdomain correlation was high for most domains (r=0.698 to 0.779), except for the correlation between Vitality and Disease domains, which showed a moderate correlation (r=0.575). For convergent validity, TH WISQoL demonstrated a good overall correlation to TH SF-36, (r=0.796, p<0.05). Conclusion: The TH WISQoL is valid and reliable for evaluating the quality of life of Thai patients with kidney stone. A further large-scale multi-center study is warranted to confirm its applicability in Thailand. Keywords: Quality of life, Kidney stone, Validation, Outcome measurement

Evaluating Qualitative Research

2017 ◽  
Author(s):  
Jeasik Cho
Keyword(s):  
Qualitative Research ◽  
Large Scale ◽  
Academic Research ◽  
Research Community ◽  
Assessment Tools ◽  
Journal Articles ◽  
Journal Editors ◽  
The Past ◽  
Grant Proposals

This book provides the qualitative research community with some insight on how to evaluate the quality of qualitative research. This topic has gained little attention during the past few decades. We, qualitative researchers, read journal articles, serve on masters’ and doctoral committees, and also make decisions on whether conference proposals, manuscripts, or large-scale grant proposals should be accepted or rejected. It is assumed that various perspectives or criteria, depending on various paradigms, theories, or fields of discipline, have been used in assessing the quality of qualitative research. Nonetheless, until now, no textbook has been specifically devoted to exploring theories, practices, and reflections associated with the evaluation of qualitative research. This book constructs a typology of evaluating qualitative research, examines actual information from websites and qualitative journal editors, and reflects on some challenges that are currently encountered by the qualitative research community. Many different kinds of journals’ review guidelines and available assessment tools are collected and analyzed. Consequently, core criteria that stand out among these evaluation tools are presented. Readers are invited to join the author to confidently proclaim: “Fortunately, there are commonly agreed, bold standards for evaluating the goodness of qualitative research in the academic research community. These standards are a part of what is generally called ‘scientific research.’ ”

scholarly journals A standardized framework for testing the performance of sleep-tracking technology: step-by-step guidelines and open-source code

SLEEP ◽  
2020 ◽  
Author(s):  
Luca Menghini ◽  
Nicola Cellini ◽  
Aimee Goldstone ◽  
Fiona C Baker ◽  
Massimiliano de Zambotti
Keyword(s):  
Open Source ◽  
Validation Studies ◽  
Large Scale ◽  
Analytical Framework ◽  
Clinical Settings ◽  
Large Scale Data ◽  
Fast Pace ◽  
Epoch Analysis ◽  
Tracking Devices

Abstract Sleep-tracking devices, particularly within the consumer sleep technology (CST) space, are increasingly used in both research and clinical settings, providing new opportunities for large-scale data collection in highly ecological conditions. Due to the fast pace of the CST industry combined with the lack of a standardized framework to evaluate the performance of sleep trackers, their accuracy and reliability in measuring sleep remains largely unknown. Here, we provide a step-by-step analytical framework for evaluating the performance of sleep trackers (including standard actigraphy), as compared with gold-standard polysomnography (PSG) or other reference methods. The analytical guidelines are based on recent recommendations for evaluating and using CST from our group and others (de Zambotti and colleagues; Depner and colleagues), and include raw data organization as well as critical analytical procedures, including discrepancy analysis, Bland–Altman plots, and epoch-by-epoch analysis. Analytical steps are accompanied by open-source R functions (depicted at https://sri-human-sleep.github.io/sleep-trackers-performance/AnalyticalPipeline_v1.0.0.html). In addition, an empirical sample dataset is used to describe and discuss the main outcomes of the proposed pipeline. The guidelines and the accompanying functions are aimed at standardizing the testing of CSTs performance, to not only increase the replicability of validation studies, but also to provide ready-to-use tools to researchers and clinicians. All in all, this work can help to increase the efficiency, interpretation, and quality of validation studies, and to improve the informed adoption of CST in research and clinical settings.

scholarly journals Implementing an Integrated Large-Scale Clinical Information System for ISSSTE’s Hospital Network in Mexico

2021 ◽  
Vol 3 (2) ◽  
pp. 444-453
Author(s):  
Arturo Cervantes Trejo ◽  
Sophie Domenge Treuille ◽  
Isaac Castañeda Alcántara
Keyword(s):  
Health Care ◽  
Information System ◽  
Health Care Services ◽  
Large Scale ◽  
Clinical Information System ◽  
Clinical Information ◽  
Public Hospitals ◽  
Care Services ◽  
Cost Reductions

AbstractThe Institute for Security and Social Services for State Workers (ISSSTE) is a large public provider of health care services that serve around 13.2 million Mexican government workers and their families. To attain process efficiencies, cost reductions, and improvement of the quality of diagnostic and imaging services, ISSSTE was set out in 2019 to create a digital filmless medical image and report management system. A large-scale clinical information system (CIS), including radiology information system (RIS), picture archiving and communication system (PACS), and clinical data warehouse (CDW) components, was implemented at ISSSTE’s network of forty secondary- and tertiary-level public hospitals, applying global HL-7 and Digital Imaging and Communications in Medicine (DICOM) standards. In just 5 months, 40 hospitals had their endoscopy, radiology, and pathology services functionally interconnected within a national CIS and RIS/PACS on secure private local area networks (LANs) and a secure national wide area network (WAN). More than 2 million yearly studies and reports are now in digital form in a CDW, securely stored and always available. Benefits include increased productivity, reduced turnaround times, reduced need for duplicate exams, and reduced costs. Functional IT solutions allow ISSSTE hospitals to leave behind the use of radiographic film and printed medical reports with important cost reductions, as well as social and environmental impacts, leading to direct improvement in the quality of health care services rendered.

scholarly journals Are “Internet+” tactics the key to poverty alleviation in China’s rural ethnic minority areas? Empirical evidence from Sichuan Province

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Xiang Yin ◽  
Zhiyi Meng ◽  
Xin Yi ◽  
Yong Wang ◽  
Xia Hua
Keyword(s):  
Ethnic Minority ◽  
Poverty Alleviation ◽  
Large Scale ◽  
Sichuan Province ◽  
Infrastructure Investment ◽  
Communication Infrastructure ◽  
Gdp Growth Rate ◽  
The Relationship ◽  
Positive Effect

AbstractChina has made great efforts to alleviate poverty in rural ethnic minority areas and targeted achieving the poverty-alleviation task by the end of 2020. Aba, Ganzi, and Liangshan, three of the poorest ethnic prefectures in Sichuan Province, Southwest China, have all implemented “Internet+” tactics since 2013, which have had the positive effect of increasing family revenues by improving communication infrastructure and encouraging the large-scale use of e-commerce. This paper aims to comprehensively investigate whether “Internet+” tactics play a key role in poverty alleviation in Sichuan’s rural ethnic minority areas and to propose further measures to enhance the efficiency of e-commerce practice. To this end, we conduct an analysis using the framework of classic growth theory and use panel data from 2000 to 2018 to examine the relationship between Communication Infrastructure Investment (CII) and a set of poverty-alleviation indicators, including local GDP growth rate (LGGR), local government revenue (LGR), and per-capita income of residents (PCIR). The results indicate that strengthening CII improves the PCIR and local economic growth, playing a key role in poverty alleviation. However, the stimulation of CII on LGGR and LGR wanes as time passes. More financial and technical actions will be needed to improve the efficiency and quality of current strategies for sustainable development in those areas.

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