Effect of Impingement Surface Velocity on Slot Jet and Slot Jet Reattachment Nozzles’ Flow Field

2019 ◽  
Author(s):  
M. Farzad ◽  
J. Yagoobi
Keyword(s):  
Numerical Study ◽  
Velocity Ratio ◽  
Surface Force ◽  
Surface Velocity ◽  
Moving Plate ◽  
Mass Entrainment ◽  
Exit Temperature ◽  
The Impact ◽  
First Time ◽  
Impingement Surface

Abstract Slot jet reattachment (SJR) nozzle is developed in an attempt to enhance heat and mass transfer characteristics while effectively controlling the impingement surface force exerted by the jet flow. In the SJR nozzle, the jet is directed outward from the nozzle exit and it then reattaches on an adjacent surface in its vicinity. The turbulent mixing occurs at the boundaries of the free stream induces secondary flow by mass entrainment and causes the flow to reattach the surface in the form of an oval reattachment at close nozzle to surface spacing [1]. All the previous studies had considered a stationary reattachment surface. This paper, for the first time, investigates the impact of reattachment surface movement on the flow structure of SJR nozzle with three different exit angles of +45°, +20°, and +10°. Specifically, this numerical study is carried out by varying the surface-to-jet velocity ratio (u* = up/ue) from 0 to 1.5 and comparing of flow reattachment flow fields to those of a regular slot jet (SJ) nozzle, where up is the speed of reattachment surface (moving plate) and ue is the jet exit velocity. In this study, jet exit temperature is kept constant at the room temperature of 20°C and all comparisons were performed at the same Reynolds number of 7,900. Additionally, the effect of SJR air exit angle on the peak surface pressure is investigated.

A Numerical Study of Electrode Arrangements for Precise Microdrop Generation in an Electrowetting-Based Digital Microfluidic Platform

2019 ◽  
Author(s):  
Yin Guan ◽  
Baiyun Li ◽  
Mengnan Zhu ◽  
Shengjie Cheng ◽  
Jiyue Tu ◽  
...  
Keyword(s):  
Free Surface ◽  
Cell Model ◽  
Numerical Study ◽  
Digital Microfluidics ◽  
Surface Force ◽  
Viscous Force ◽  
Generation Process ◽  
Parallel Plates ◽  
Digital Microfluidic ◽  
The Impact

Abstract Owing to the wide applications in a large variety of multi-disciplinary areas, electrowetting-based digital microfluidics (DMF) has received considerable attention in the last decade. However, because of the complexity involved in the droplet generation process, the techniques and configurations for precise and controllable microdrop generation are still unclear. In this paper, a numerical study has been performed to investigate the impact of electrode arrangements on microdrop generation in an electrowetting-based DMF Platform proposed by a previously published experimental work. The governing equations for the microfluidic flow are solved by a finite volume formulation with a two-step projection method on a fixed numerical domain. The free surface of the microdrop is tracked by a coupled level-set and volume-of-fluid (CLSVOF) method, and the surface tension at the free surface is computed by the continuum surface force (CSF) scheme. A simplified viscous force scheme based on the ‘Hele-Shaw cell’ model is adopted to evaluate the viscous force exerted by the parallel plates. The generation process has been simulated with three different electrode arrangements, namely, ‘SL’, ‘SW’, and ‘SQ’. The effect of electrode arrangement on microdrop volume has been investigated. Besides, the influences of the initial microdrop location and volume on the generation process for the ‘SL’ design have been studied. The results can be used to advance microdrop generation techniques for various electrowetting-based DMF applications.

scholarly journals Computation of heat transfer of a plane turbulent jet impinging a moving plate

2014 ◽  
Vol 18 (4) ◽  
pp. 1259-1271 ◽  
Author(s):  
Dahbia Benmouhoub ◽  
Amina Mataoui
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Nusselt Number ◽  
Flow Field ◽  
Velocity Ratio ◽  
Local Heat Transfer ◽  
Slight Modification ◽  
Surface Velocity ◽  
Moving Plate ◽  
Jet Velocity

This study examines the performance of one point closure turbulence models in predicting of heat and momentum transfer of impinging flows. The scope of this paper is limited to impinging jet on a moving wall and heat transfer. The impinging distance is fixed to 8 thickness of the nozzle (8e) for this study. Two parameters are considered: the jet exit Reynolds number (10000?Re?25000) and the jet-surface velocity ratio (0?Rsj?4). the flow field structure at a given surface-to-jet velocity ratio is independent of the jet Reynolds number, a slight modification of the flow field is observed for low surface-to-jet velocity ratio (Rsj<0.25) whereas at higher ratios Rsj>0.25, the flow field is significantly modified. Good agreement with experimental results is obtained for surface-to-jet velocity ratio 0?Rsj?2. the purpose of this paper is to consider the case of higher of surface-to-jet velocity Rsj>2. A further study of heat transfer is achieved and shows that the stagnation points the local heat transfer coefficient have a maximum value. The local Nusselt number at the impinging region tends to decrease significantly when Rsj?1.5. The evolution of average Nusselt number is correlated according to the surface-to-jet velocity ratios for each Reynolds number.

scholarly journals A Numerical Study on the Impact of Building Dimensions on Airflow Patterns and Bed Morphology around Buildings at the Beach

2021 ◽  
Vol 10 (1) ◽  
pp. 13
Author(s):  
Paran Pourteimouri ◽  
Geert H. P. Campmans ◽  
Kathelijne M. Wijnberg ◽  
Suzanne J. M. H. Hulscher
Keyword(s):  
Wind Direction ◽  
Numerical Study ◽  
Field Measurements ◽  
Surface Velocity ◽  
Erosion And Deposition ◽  
Transport Pathways ◽  
Near Surface ◽  
Deposition Patterns ◽  
Numerical Predictions ◽  
The Impact

The attractiveness of beaches to people has led, in many places, to the construction of buildings at the beach–dune interface. Buildings change the local airflow patterns which, in turn, alter the sediment transport pathways and magnitudes. This induces erosion and deposition patterns around the structures. In this study, a numerical model is developed using the open-source computational fluid dynamics solver OpenFOAM. First, the model is used to predict the airflow patterns around a single rectangular building. The model predictions are validated with wind-tunnel data, which show good agreements. Second, a reference beach building is introduced and then the building dimensions are increased in length, width and height, each up to three times the reference building dimension. The impact of each dimensional extent on the near-surface airflow patterns is investigated. The results show that the near-surface airflow patterns are least dependent on the length of the building in the wind direction and they depend most on the width of the building perpendicular to the wind direction. Third, the convergence of the third-order horizontal near-surface velocity field is calculated to interpret the impact of changes in airflow patterns on potential erosion and deposition patterns around the building. The numerical predictions are compared with the observed erosion and sedimentation patterns around scale models in the field. The comparisons show satisfactory agreements between numerical results and field measurements.

scholarly journals A Numerical and Experimental Investigation of the Impact of Mixed Flow Turbine Inlet Cone Angle and Inlet Blade Angle

2018 ◽  
Author(s):  
Thomas Leonard ◽  
Stephen Spence ◽  
Dietmar Filsinger ◽  
Andre Starke
Keyword(s):  
Numerical Study ◽  
Velocity Ratio ◽  
Cone Angle ◽  
Blade Angle ◽  
Mixed Flow ◽  
Automotive Engine ◽  
Transient Behaviour ◽  
Design Changes ◽  
Wide Range ◽  
The Impact

Mixed flow turbines offer potential benefits for turbocharged engines when considering off-design performance and engine transient behaviour. Although the performance and use of mixed flow turbines is described in the literature, little is published on the combined impact of the cone angle and the inlet blade angle, which are the defining features of such turbines. Numerical simulations were completed using a CFD model that was validated against experimental measurements for a baseline geometry. The mechanical impact of the design changes was also analysed. Based on the results of the numerical study, two rotors of different blade angle and cone angle were selected and manufactured. These rotors were tested using the QUB low temperature turbine test rig, which allowed for accurate and wide range mapping of the turbine performance to low values of velocity ratio. The performance results from these additional rotors were used to further validate the numerical findings. The numerical model was used to understand the underlying physical reasons for the measured performance differences through detailed consideration of the flow field at rotor inlet, and to document how the loss mechanisms and secondary flow structures developed with varying rotor inlet geometry. It was observed that large inlet blade cone angles resulted in strong separation and flow blockage near the hub at off-design conditions, which greatly reduced efficiency. However, the significant rotor inertia benefits achieved with the large blade cone angles were shown to compensate for the efficiency penalties and could be expected to deliver improved transient performance in downsized automotive engine applications.

Numerical and Experimental Investigation of the Impact of Mixed Flow Turbine Inlet Cone Angle and Inlet Blade Angle

2019 ◽  
Vol 141 (8) ◽  
Author(s):  
Thomas Leonard ◽  
Stephen Spence ◽  
Andre Starke ◽  
Dietmar Filsinger
Keyword(s):  
Numerical Study ◽  
Velocity Ratio ◽  
Cone Angle ◽  
Transient Behavior ◽  
Blade Angle ◽  
Mixed Flow ◽  
Automotive Engine ◽  
Design Changes ◽  
Wide Range ◽  
The Impact

Mixed flow turbines (MFTs) offer potential benefits for turbocharged engines when considering off-design performance and engine transient behavior. Although the performance and use of MFTs are described in the literature, little is published on the combined impact of the cone angle and the inlet blade angle, which are the defining features of such turbines. Numerical simulations were completed using a computational fluid dynamics (CFD) model that was validated against experimental measurements for a baseline geometry. The mechanical impact of the design changes was also analyzed. Based on the results of the numerical study, two rotors of different blade angle and cone angle were selected and manufactured. These rotors were tested using the Queen's University Belfast (QUB) low-temperature turbine test rig, which allowed for accurate and wide-range mapping of the turbine performance to low values of the velocity ratio. The performance results from these additional rotors were used to further validate the numerical findings. The numerical model was used to understand the underlying physical reasons for the measured performance differences through detailed consideration of the flow field at the rotor inlet and to document how the loss mechanisms and secondary flow structures developed with varying rotor inlet geometry. It was observed that large inlet blade cone angles resulted in strong separation and flow blockage near the hub at off-design conditions, which greatly reduced efficiency. However, the significant rotor inertia benefits achieved with the large blade cone angles were shown to compensate for the efficiency penalties and could be expected to deliver improved transient performance in downsized automotive engine applications.

Relationship between big five personality model and abusive supervision

2019 ◽  
Vol 12 (2) ◽  
Author(s):  
Bibi Tahira ◽  
Naveed Saif ◽  
Muhammad Haroon ◽  
Sadaqat Ali
Keyword(s):  
Big Five ◽  
Abusive Supervision ◽  
State Universities ◽  
Big Five Personality ◽  
Big Five Model ◽  
The Impact ◽  
First Time ◽  
Supervisor Behavior ◽  
Moderating Role

The current study tries to understand the diverse nature of relationship between personality Big Five Model (PBFM) and student's perception of abusive supervision in higher education institutions of Khyber Pakhtoonkhwa Pakistan. Data was collected in dyads i.e. (supervisors were asked to rate their personality attributes while student were asked to rate the supervisor behavior) through adopted construct. For this purpose, data was collected from three government state universities and one Private Sector University. The focus was on MS/M.Phill and PhD student and their supervisors of the mentioned universities. After measuring normality and validity regression analysis was conducted to assess the impact of supervisor personality characteristics that leads to abusive supervision. Findings indicate interestingly that except agreeableness other four attributes of (PBFM) are play their role for abusive supervision. The results are novel in the nature as for the first time Neuroticism, openness to experience, extraversion and conscientiousness are held responsible for the abusive supervision. The study did not explore the demographic characteristics, and moderating role of organizational culture, justice and interpersonal deviances to understand the strength of relationship in more detail way. Keywords: Personality big five model, abusive supervision, HEIs

The Influence of TRIPS Compliant Patent Laws on Indian Pharmaceutical Industry

2014 ◽  
Vol 4 (1) ◽  
Author(s):  
Rupesh Rastogi ◽  
Virendra Kumar
Keyword(s):  
Pharmaceutical Industry ◽  
Patent Protection ◽  
Uruguay Round ◽  
Pharmaceutical Products ◽  
Trips Agreement ◽  
Patent Law ◽  
Patent Laws ◽  
The Impact ◽  
First Time ◽  
Indian Pharmaceutical Industry

The first legislation in India relating to patents was the Act VI of 1856. The Indian Patents and Design Act, 1911 (Act II of 1911) replaced all the previous Acts. The Act brought patent administration under the management of Controller of Patents for the first time. After Independence, it was felt that the Indian Patents & Designs Act, 1911 was not fulfilling its objective. Various comities were constituted to recommend, framing a patent law which can fulfill the requirement of Indian Industry and people. The Indian Patent Act of 1970 was enacted to achieve the above objectives. The major provisions of the act, provided for process, not the product patents in food, medicines, chemicals with a term of 14 years and 5-7 for chemicals and drugs. The Act enabled Indian citizens to access cheapest medicines in the world and paved a way for exponential growth of Indian Pharmaceutical Industry. TRIPS agreement, which is one of the important results of the Uruguay Round, mandated strong patent protection, especially for pharmaceutical products, thereby allowing the patenting of NCEs, compounds and processes. India is thereby required to meet the minimum standards under the TRIPS Agreement in relation to patents and the pharmaceutical industry. India’s patent legislation must now include provisions for availability of patents for both pharmaceutical products and processes inventions. The present paper examines the impact of change in Indian Patent law on Pharmaceutical Industry.

The impact of traditional plants and their secondary metabolites in the discovery of COVID-19 treatment

2020 ◽  
Vol 26 ◽  
Author(s):  
Shabana Bibi ◽  
Ayesha Sarfraz ◽  
Ghazala Mustafa ◽  
Zeeshan Ahmed ◽  
Muhammad Aurang Zeb ◽  
...  
Keyword(s):  
Secondary Metabolites ◽  
Test System ◽  
Chemical Information ◽  
System Type ◽  
The Family ◽  
Comprehensive Search ◽  
Coronavirus Infection ◽  
The Impact ◽  
First Time ◽  
Plant Sources

Background: Coronavirus Disease-2019 belongs to the family of viruses which cause a serious pneumonia along with fever, breathing issues and infection of lungs for the first time in China and later spread worldwide. Objective: Several studies and clinical trials have been conducted to identify potential drugs and vaccines for Coronavirus Disease-2019. The present study listed natural secondary metabolites identified from plant sources with antiviral properties and could be safer and tolerable treatment for Coronavirus Disease-2019. Methods: A comprehensive search on the reported studies was conducted using different search engine such as Google scholar, SciFinder, Sciencedirect, Medline PubMed, and Scopus for the collection of research articles based on plantderived secondary metabolites, herbal extracts, and traditional medicine for coronavirus infections. Results: Status of COVID-19 worldwide and information of important molecular targets involved in COVID-19 is described and through literature search, is highlighted that numerous plant species and their extracts possess antiviral properties and studied with respect to Coronavirus treatments. Chemical information, plant source, test system type with mechanism of action for each secondary metabolite is also mentioned in this review paper. Conclusion: The present review has listed plants that have presented antiviral potential in the previous coronavirus pandemics and their secondary metabolites which could be significant for the development of novel and a safer drug which could prevent and cure coronavirus infection worldwide.

Individual and Combined Assessment of Ser680Asn FSH Receptor and FSHβ -211 G>T Gene Polymorphisms in Ovarian Response in IVF/ICSI Program

2020 ◽  
Vol 21 ◽  
Author(s):  
Elli Anagnostou ◽  
Alexia Kafkoutsou ◽  
Despina Mavrogianni ◽  
Ekaterini Domali ◽  
Evangelia Dimitroulia ◽  
...  
Keyword(s):  
Gene Polymorphism ◽  
Gene Polymorphisms ◽  
Ovarian Response ◽  
Greek Population ◽  
Control Group ◽  
Genotype Distribution ◽  
Β Subunit ◽  
Molecular Genetic Study ◽  
The Impact ◽  
First Time

Background: Molecular biology tools, such as the detection of single nucleotide polymorphisms (SNPs), have been considered to assist to the management of the ovarian stimulation protocols. Purpose: The aim of this study was to evaluate the impact of two polymorphisms, the Asn680Ser polymorphism of the FSHR gene, and the FSH β subunit (FSHβ) gene polymorphism -211 G>T, in a Greek population of women undergoing IVF/ICSI program in our center. In addition, a control group of fertile women was studied, to verify whether there are differences in the genotype distribution between fertile and infertile population for both polymorphisms, as the FSHβ gene polymorphism -211 G>T is studied for the first time in the Greek population. Results : The FSH β-211 G>T polymorphism, studied for the first time in the Greek infertile population, appears to be quite rare. When studying the two polymorphisms separately, statistically significant differences were obtained that concerned the LH levels. Discussion: According to the combination analysis of the two polymorphisms by the number of alleles, women with 2-3 polymorphic alleles needed more days of stimulation, but there were no differences in pregnancy rates. Conclusion: This molecular genetic study helps to elucidate whether the polygenic combination of the Asn680Ser and FSH β subunit -211 G>T gene polymorphisms is of additive value in the prediction of ovarian response to exogenous gonadotropins.

Reconstituting the International, 1918–1923

2017 ◽  
Author(s):  
Talbot C. Imlay
Keyword(s):  
Seismic Events ◽  
Great War ◽  
Bolshevik Revolution ◽  
Meaning And Purpose ◽  
Post War ◽  
The Impact ◽  
First Time ◽  
The Great War ◽  
Do So ◽  
Lengthy Process

This chapter examines the post-war efforts of European socialists to reconstitute the Socialist International. Initial efforts to cooperate culminated in an international socialist conference in Berne in February 1919 at which socialists from the two wartime camps met for the first time. In the end, however, it would take four years to reconstitute the International with the creation of the Labour and Socialist International (LSI) in 1923. That it took so long to do so is a testimony to the impact of the Great War and to the Bolshevik revolution. Together, these two seismic events compelled socialists to reconsider the meaning and purpose of socialism. The search for answers sparked prolonged debates between and within the major parties, profoundly reconfiguring the pre-war world of European socialism. One prominent stake in this lengthy process, moreover, was the nature of socialist internationalism—both its content and its functioning.

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