scholarly journals Numerical Insight into the Kelvin-Helmholtz Instability Appearance in Cavitating Flow

2021 ◽  
Vol 11 (6) ◽  
pp. 2644
Author(s):  
Peter Pipp ◽  
Marko Hočevar ◽  
Matevž Dular
Keyword(s):  
Cavitating Flow ◽  
Helmholtz Instability ◽  
The Third ◽  
Turbulent Eddies ◽  
Condensation Shock Wave ◽  
Condensation Shock ◽  
Computational Fluid Dynamics Cfd ◽  
Experimental Findings ◽  
Vapor Region ◽  
Insight Into

Recently the development of Kelvin-Helmholtz instability in cavitating flow in Venturi microchannels was discovered. Its importance is not negligible, as it destabilizes the shear layer and promotes instabilities and turbulent eddies formation in the vapor region, having low density and momentum. In the present paper, we give a very brief summary of the experimental findings and in the following, we use a computational fluid dynamics (CFD) study to peek deeper into the onset of the Kelvin-Helmholtz instability and its effect on the dynamics of the cavitation cloud shedding. Finally, it is shown that Kelvin-Helmholtz instability is beside the re-entrant jet and the condensation shock wave the third mechanism of cavitation cloud shedding in Venturi microchannels. The shedding process is quasi-periodic.

Recovery boiler sootblowers: History and technological advances

TAPPI Journal ◽  
2015 ◽  
Vol 14 (1) ◽  
pp. 51-60
Author(s):  
HONGHI TRAN ◽  
DANNY TANDRA
Keyword(s):  
Cfd Modeling ◽  
Computing Systems ◽  
The Past ◽  
Technological Advances ◽  
Recovery Boilers ◽  
Computational Fluid Dynamics Cfd ◽  
Recovery Boiler ◽  
Steam Parameters ◽  
Insight Into ◽  
Deposit Removal

Sootblowing technology used in recovery boilers originated from that used in coal-fired boilers. It started with manual cleaning with hand lancing and hand blowing, and evolved slowly into online sootblowing using retractable sootblowers. Since 1991, intensive research and development has focused on sootblowing jet fundamentals and deposit removal in recovery boilers. The results have provided much insight into sootblower jet hydrodynamics, how a sootblower jet interacts with tubes and deposits, and factors influencing its deposit removal efficiency, and have led to two important innovations: fully-expanded sootblower nozzles that are used in virtually all recovery boilers today, and the low pressure sootblowing technology that has been implemented in several new recovery boilers. The availability of powerful computing systems, superfast microprocessors and data acquisition systems, and versatile computational fluid dynamics (CFD) modeling capability in the past two decades has also contributed greatly to the advancement of sootblowing technology. High quality infrared inspection cameras have enabled mills to inspect the deposit buildup conditions in the boiler during operation, and helped identify problems with sootblower lance swinging and superheater platens and boiler bank tube vibrations. As the recovery boiler firing capacity and steam parameters have increased markedly in recent years, sootblowers have become larger and longer, and this can present a challenge in terms of both sootblower design and operation.

No fear of George Kingsley Zipf

10.1558/37291 ◽  
2018 ◽  
Vol 2 (2) ◽  
pp. 242-263
Author(s):  
Stefano Rastelli ◽  
Kook-Hee Gil
Keyword(s):  
Minimalist Program ◽  
Classroom Research ◽  
Language Design ◽  
Efficient Computation ◽  
Generative Linguistics ◽  
The Third ◽  
Factor Effect ◽  
Language Classroom ◽  
Recent Developments ◽  
Insight Into

This paper offers a new insight into GenSLA classroom research in light of recent developments in the Minimalist Program (MP). Recent research in GenSLA has shown how generative linguistics and acquisition studies can inform the language classroom, mostly focusing on what linguistic aspects of target properties should be integrated as a part of the classroom input. Based on insights from Chomsky’s ‘three factors for language design’ – which bring together the Faculty of Language, input and general principles of economy and efficient computation (the third factor effect) for language development – we put forward a theoretical rationale for how classroom research can offer a unique environment to test the learnability in L2 through the statistical enhancement of the input to which learners are exposed.

Marketing Responsible Drinking Effectively to Young Adults

2014 ◽  
Vol 1 (1) ◽  
Author(s):  
Colby Doyle ◽  
Matthew Gaudet ◽  
Dominic Lay ◽  
Amber McLeod ◽  
Robert Schaeffer
Keyword(s):  
Quantitative Research ◽  
Drinking Patterns ◽  
Major Question ◽  
The Public ◽  
The Third ◽  
Current Consumption ◽  
Sample Data ◽  
Vague Quantifiers ◽  
Insight Into ◽  
Alberta Health

The primary goal of this research is to identify and examine the components of responsible drinking advertisements. We will examine industry and government related advertisements as we try to understand one of our major questions: does the source influence the validity of the message? The next group of major questions that we will be looking to answer is how are the vague quantifiers used in responsible drinking campaigns interpreted by the public?  How many drinks do people consider “too much?” What does “drink responsibly” really mean? The third major question is whether or not an individual’s current consumption patterns of alcohol have any effect on how individuals assess responsible drinking campaigns. Our qualitative research has indicated that social influences can be strongly related with drinking patterns; this will be further examined in our quantitative research. Also, we will be looking into some of the psychology behind industry and government sponsored advertisements as well as gathering and interpreting information from a sample of our target demographic. Our target demographic consists of both male and females between the ages 18-24. Our literature review and qualitative analysis gave us good insight into some of the potential answers to our questions. We will use these potential answers from our previous research to guide us as we attempt to conduct conclusive research based on a sample data of 169 individuals. Our findings will aid us in developing conclusions and recommendations for Alberta Health Services.

Attitudes of Elderly People in the South Moravian Region to Further Education

2014 ◽  
Vol 4 (2) ◽  
pp. 54-78
Author(s):  
Petr Adamec ◽  
Marián Svoboda
Keyword(s):  
Quality Of Life ◽  
Elderly People ◽  
Further Education ◽  
The South ◽  
The Third ◽  
Interesting Insight ◽  
Survey Results ◽  
Insight Into ◽  
Demographic Features

This paper deals with the results of sociological survey focused on identification of the attitudes of elderly people to further education. The research was carried out in September 2010. Experience of elderly people with further education, their readiness (determination) for further education as well as their motivation and barriers in further education were also subjects of this research. Detecting elderly population’s awareness of universities of the third age and finding out their further education preferences were an integral part of the research. Research sample consisted of citizens over 55 years living in the South Moravian region. The survey results are structured by socio-demographic features e.g.: age, sex, educational attainment etc. and provide an interesting insight into the attitudes of the target group to one of the activities that contributes to improvement of their quality of life.

scholarly journals Comparative Study for the Prediction of Cavitating Flow inside a Square-Edged Orifice using Different Commercial CFD Software

2019 ◽  
Vol 128 ◽  
pp. 06003
Author(s):  
Gong-Hee Lee ◽  
June-Ho Bae
Keyword(s):  
Structural Damage ◽  
Nuclear Power ◽  
Cavitating Flow ◽  
Regulatory Body ◽  
Reactor Operation ◽  
Flow Acceleration ◽  
Service Testing ◽  
Ansys Cfx ◽  
Rapid Flow ◽  
Computational Fluid Dynamics Cfd

Nuclear power plant operators conduct in-service testing (IST) to verify the safety functions of safety–related pumps and valves and to monitor the degree of vulnerability over time during reactor operation. The system to which the pump and valve to be tested are installed has various sizes of orificesfor flow control and decompression. Rapid flow acceleration and accompanying pressure drop may cause cavitation inside the orifice, which may result in orifice degradation and structural damage. Though licensing applications supported by using Computational Fluid Dynamics (CFD) software are gradually increasing for IST–related problems, there is no CFD software which obtains a licensing from the domestic regulatory body until now. In this paper, to assess the prediction performance of different commercialCFD software for the analysis of cavitating flow inside a square–edged orifice, the simulation was conducted with ANSYS CFX and FLUENT R18.1. The results predicted were then compared with the measured data.

Numerical Simulation of Insulin Depot Formation and Absorption in Subcutaneous Tissue Modeled as a Homogeneous Anisotropic Porous Media

2021 ◽  
Author(s):  
Michael Zedelmair ◽  
Abhijit Mukherjee
Keyword(s):  
Porous Media ◽  
Numerical Model ◽  
Insulin Pump ◽  
Subcutaneous Tissue ◽  
Saturated Porous Media ◽  
Anisotropic Porous Media ◽  
Effective Option ◽  
Computational Fluid Dynamics Cfd ◽  
Experimental Findings ◽  
Subcutaneous Adipose

Abstract In this study, a numerical model of the insulin depot formation and absorption in the subcutaneous adipose tissue is developed using the commercial Computational Fluid Dynamics (CFD) software. A better understanding of these mechanisms can be helpful in the development of new devices and cannula geometries as well as predicting the concentration of insulin in the blood. The injection method considered in this simulation is by the use of an insulin pump using a rapid acting U100 insulin analogue. The depot formation is analyzed running Bolus injections ranging from 5-15 units of insulin corresponding to 50-150µl. The insulin is injected into the subcutaneous tissue in the abdominal region. The tissue is modeled as a fluid saturated porous media. An anisotropic approach to define the tissue permeability is studied by varying the value of the porosity in parallel and perpendicular direction having an impact on the viscous resistance to the flow. Following recent experimental findings this configuration results in a disk shaped insulin depot. To be able to run the simulation over longer timeframes the depot formation model has been extended implementing the process of absorption of insulin from the depot. The developed model is then used to analyze the formation of the insulin depot in the tissue when using different flow rates and cannula geometries. The numerical model is an effective option to evaluate new cannula designs prior to the manufacturing and testing of prototypes, which are rather time consuming and expensive.

scholarly journals Impact of COVID-19 Variants on the Second Wave in India and Subsequent Discretion of Possibilities of the Third Wave

2021 ◽  
pp. 115-126
Author(s):  
Sudarshan Ramaswamy ◽  
Meera Dhuria ◽  
Sumedha M. Joshi ◽  
Deepa H Velankar
Keyword(s):  
Herd Immunity ◽  
Sir Model ◽  
The Other ◽  
Third Wave ◽  
Focal Points ◽  
Current Analysis ◽  
The Third ◽  
The Impact ◽  
Second Wave ◽  
Insight Into

Introduction: Epidemiological comprehension of the COVID-19 situation in India can be of great help in early prediction of any such indications in other countries and possibilities of the third wave in India as well. It is essential to understand the impact of variant strains in the perspective of the rise in daily cases during the second wave – Whether the rise in cases witnessed is due to the reinfections or the surge is dominated by emergence of mutants/variants and reasons for the same. Overall objective of this study is to predict early epidemiological indicators which can potentially lead to COVID-19 third wave in India. Methodology: We analyzed both the first and second waves of COVID-19 in India and using the data of India’s SARS-CoV-2 genomic sequencing, we segregated the impact of the Older Variant (OV) and the other major variants (VOI / VOC).  Applying Kermack–McKendrick SIR model to the segregated data progression of the epidemic in India was plotted in the form of proportion of people infected. An equation to explain herd immunity thresholds was generated and further analyzed to predict the possibilities of the third wave. Results: Considerable difference in ate of progression of the first and second wave was seen. The study also ascertains that the rate of infection spread is higher in Delta variant and is expected to have a higher threshold (>2 times) for herd immunity as compared to the OV. Conclusion: Likelihood of the occurrence of the third wave seems unlikely based on the current analysis of the situation, however the possibilities cannot be ruled out. Understanding the epidemiological details of the first and second wave helped in understanding the focal points responsible for the surge in cases during the second wave and has given further insight into the future.

scholarly journals An Analytical study of Bediuzzaman Said Nursi’s Intellectual Development and Composition of Risale-i Nur (a Thematic Qur’ānic Exegesis)

2020 ◽  
Vol 10 (2) ◽  
Author(s):  
Dr. Shumaila Majeed
Keyword(s):  
Intellectual Development ◽  
Analytical Study ◽  
Muslim Community ◽  
The Third ◽  
Life Education ◽  
Representative Work ◽  
Qur'anic Exegesis ◽  
Islamic Belief ◽  
Distinguishing Features ◽  
Insight Into

The current study analyses Bediuzzaman Said Nursi’s life and contributions. It presents a short description of his early life, education and dissatisfaction with the then prevailing education systems. This is followed by an analysis of his intellectual development due to rapidly changing circumstances. The paper also presents an insight into Nursi’s representative work ‘Risale-i Nur’ through an analysis of its structure and methodology. This is significant because his intellectual development, due to changes in his circumstances, played an instrumental role in determining the style, method and objectives of Risale. Hence, the study of his intellectual development is imperative to understand the objectives of Risale. The findings of the paper revealed that Nursi’s approach to reform the Muslim society was not stagnant. In the ‘Old Said’ phase, he attempted to neutralize the decline in Muslim community through sociopolitical reforms. The ‘New Said’ phase was marked by his efforts to strengthen belief, encounter anti-religious ideologies and detachment from politics. In the ‘Third Said’ phase, he again took interest in sociopolitical matters but it was limited to the theoretical realm with no practical involvement. The study also found that the structure of Risale, its treatment of subjects and its methodology are its distinguishing features. It consists of the elements well-suited to the needs of the time to save Islamic belief against the onslaught of atheistic ideologies. The current research was conducted using the qualitative approach. It is beneficial for academia in understanding the intellectual development of this great 20th century Turkish Muslim scholar.

scholarly journals Transcendental Philosophy as a Research Programme

2021 ◽  
Vol 40 (3) ◽  
pp. 93-126
Author(s):  
Michael Lewin
Keyword(s):  
Research Programme ◽  
Transcendental Philosophy ◽  
Pure Reason ◽  
Critique Of Pure Reason ◽  
The Third ◽  
Definite Form ◽  
Historical Investigation ◽  
Clear Idea ◽  
Different Levels ◽  
Insight Into

Transcendental philosophy was not born like Athena out of Zeus’s head, mature and in full armour from the very beginning. That is why in both prefaces to the Critique of Pure Reason (1781 and 1787) Kant introduces the concept of transcendental philosophy as an “idea.” The idea understood architectonically develops slowly and only gradually acquires a definite form. As witnessed by the works of Kant himself and of his predecessors and followers, the idea of transcendental philosophy has undergone a series of changes and adjustments compared to the initial plan. In this context, my goal is not simply exegesis and historical investigation of transcendental philosophy, but also to look at it from a systematic and methodological perspective. I examine the concept of transcendental philosophy from the viewpoint of programmatic metaphilosophy. The first part discusses programmatics as a distinct subsection of metaphilosophy. I argue that Kant’s architectonic methodology and the methodology of Lakatos can be used to understand the inception, development and degradation of philosophical systems. In the second part I look at the project of transcendental philosophy and the stages of its development from the standpoint of architectonics. The third part shows that Lakatos’s methodology can provide a detailed insight into the elements of transcendental philosophy, a clear idea of its logic and identify the component parts that can be improved and developed. In spite of the different levels of detailing and epistemological prerequisites, the methodologies of Kant and Lakatos can be combined to achieve a metaphilosophically informed and progressive understanding of philosophical projects.

A Single Xyloglucan Xylosyltransferase is Sufficient for Generation of the XXXG Xylosylation Pattern of Xyloglucan

2021 ◽  
Author(s):  
Ruiqin Zhong ◽  
Dennis R Phillips ◽  
Zheng-Hua Ye
Keyword(s):  
Recombinant Proteins ◽  
Cell Walls ◽  
Degree Of Polymerization ◽  
Primary Cell ◽  
Hek293 Cells ◽  
Biochemical Mechanism ◽  
The Third ◽  
Insight Into

Abstarct Xyloglucan is the most abundant hemicellulose in the primary cell walls of dicots. Dicot xyloglucan is the XXXG-type consisting of repeating units of three consecutive xylosylated Glc residues followed by one unsubstituted Glc. Its xylosylation is catalyzed by xyloglucan 6-xylosyltransferases (XXTs) and there exist five XXTs (AtXXT1-5) in Arabidopsis. While AtXXT1and AtXXT2 have been shown to add the first two Xyl residues in the XXXG repeat, which XXTs are responsible for the addition of the third Xyl residue remains elusive although AtXXT5 was a proposed candidate. In this report, we generated recombinant proteins of all five Arabidopsis XXTs and one rice XXT (OsXXT1) in the mammalian HEK293 cells and investigated their ability to sequentially xylosylate Glc residues to generate the XXXG xylosylation pattern. We found that like AtXXT1/2, AtXXT4 and OsXXT1 could efficiently xylosylate the cellohexaose (G6) acceptor to produce mono- and di-xylosylated G6, whereas AtXXT5 was only barely capable of adding one Xyl onto G6. When AtXXT1-catalyzed products were used as acceptors, AtXXT1/2/4 and OsXXT1 but not AtXXT5 were able to xylosylate additional Glc residues to generate tri- and tetra-xylosylated G6. Further characterization of the tri- and tetra-xylosylated G6 revealed that they had the sequence of GXXXGG and GXXXXG with three and four consecutive xylosylated Glc residues, respectively. In addition, we have found that although tri-xylosylation occurred on G6, cello-oligomers with a degree of polymerization of 3 to 5 could only be mono- and di-xylosylated. Together, these results indicate that each of AtXXT1/2/4 and OsXXT1 is capable of sequentially adding Xyl onto three contiguous Glc residues to generate the XXXG xylosylation pattern and these findings provide new insight into the biochemical mechanism underlying xyloglucan biosynthesis.

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