Mean Diameters in Parallel-Flow and Counter-Flow Aerosol Systems

1976 ◽  
Vol 98 (2) ◽  
pp. 297-302 ◽  
Author(s):  
K. G. T. Hollands ◽  
K. C. Goel
Keyword(s):  
Mass Transfer ◽  
Continuous Phase ◽  
General Concept ◽  
Parallel Flow ◽  
General Definition ◽  
Single Pair ◽  
Counter Flow ◽  
Mean Diameter ◽  
The Mean ◽  
Definition Of

The general concept of the mean diameter of the disperse phase of an aerosol system, first introduced by Mugele and Evans in 1951, has proven to be a very useful one. In this concept, the proper mean diameter, xp,q, is characterized by a single pair of indices, p and q, which are dependent on the actual type of aerosol system under consideration. This paper re-examines the validity of this concept of mean diameter in heat and mass transfer aerosol systems. The concept is found to be applicable only under a very narrow range of conditions. Attention is then given to a more general definition of a mean diameter, applicable to aerosol heat or mass exchangers. Analyses of these devices shows that the more general mean diameter is a function of the capacity rate ratio, R, and effectiveness of the heat exchanger, ε. Solutions to the governing equations have permitted the mean diameter to be presented graphically as a function of these variables. These solutions are given for two types of particle size distributions, the Rosin-Rammler and the log-probability, and for both parallel-flow and counter-flow heat exchangers. The solutions are, however, restricted to cases where the resistance to heat or mass transfer lies exclusively in the continuous phase.

The Anatomy of the Callosomarginal Artery

Neurosurgery ◽  
2010 ◽  
Vol 66 (3) ◽  
pp. 602-610 ◽  
Author(s):  
Daniel D. Cavalcanti ◽  
Felipe C. Albuquerque ◽  
Benjamin F. Silva ◽  
Robert F. Spetzler ◽  
Mark C. Preul
Keyword(s):  
Anterior Cerebral Artery ◽  
Convex Curve ◽  
Anterior Communicating Artery ◽  
Morphometric Measurements ◽  
Pericallosal Artery ◽  
Mean Diameter ◽  
Best Fitting ◽  
The Mean ◽  
Definition Of ◽  
Distal Anterior Cerebral Artery

Abstract BACKGROUND The callosomarginal artery (CMA), the main branch of the pericallosal artery, courses in or near the cingulate sulcus and gives rises to 2 or more major cortical branches. There is confusion about the artery best fitting the definition of “callosomarginal artery.” Distal anterior cerebral artery aneurysms represent 1.5% to 9% of intracranial aneurysms, and most often occur at the origin of the CMA. The microsurgical anatomic features of the CMA, its relationship with the pericallosal artery, and clinical implications are presented. METHODS The origin, course, branching pattern, and diameter of the CMA and its branches and its relationship with the pericallosal artery were studied in 60 cerebral hemispheres, including cadaveric dissections and angiographic images. RESULTS The CMA was present in 93.3% of hemispheres studied and arose mainly from A3 (55.2%), a mean of 3.11 ± 1.90 cm from the anterior communicating artery. The mean diameter of the CMA at its origin was 1.53 ± 0.36 mm. The CMA ran 1.28 ± 0.89 cm until its first branch, describing an anterior convex curve backward and upward (60.7%). An average of 3 lesser branches originated from the CMA. The most consistent branch was the posterior internal frontal artery (67.9%). The mean diameter of the CMA branches was 0.93 ± 0.33 mm. CONCLUSION These morphometric measurements can help neurosurgeons access lesions located in distal intracranial vessels. The vessel coursing the longest pathway in or near the cingulate sulcus and otherwise following Moscow's classic definition should be considered the CMA.

scholarly journals Experimental results for guidance and design criteria of horizontal end-dumping type river closure

RBRH ◽  
2018 ◽  
Vol 23 (0) ◽  
Author(s):  
Joice de Oliveira Petrecca Tomaschitz ◽  
Michael Mannich ◽  
José Junji Ota
Keyword(s):  
Water Surface ◽  
Experimental Tests ◽  
Design Criteria ◽  
It Use ◽  
River Diversion ◽  
Limit Condition ◽  
Hydraulic Models ◽  
Mean Diameter ◽  
The Mean ◽  
Definition Of

ABSTRACT The river diversion involves the construction of cofferdams when dumped material is exposed at high velocities, which may cause the drag of blocks. Classical equations relate the mean rock diameter to the drop of water surface between the upstream and downstream. Results of 283 experimental tests performed in hydraulic models allowed the definition of a relationship between water surface drop and mean diameter in the limit condition of stability. The result obtained was d = 0.33×ΔH, consistent with classical equations and validating their applicability, suggesting it use for design and analysis.

The Content of the Concept of «Conclusion» in the Civil Process

2021 ◽  
pp. 48-53
Author(s):  
Ryzhkov K. S. ◽  
Keyword(s):  
Russian Federation ◽  
Civil Procedure ◽  
General Concept ◽  
General Definition ◽  
Civil Process ◽  
Procedural Law ◽  
Expert Opinions ◽  
Procedure Code ◽  
The Russian Federation ◽  
Definition Of

The article analyzes the problems associated with the content and scope of the concept of «conclusion» in civil procedural law. The absence of a definition of the concept of «conclusion» in the current legislation is noted, as well as the discussion that exists in the scientific literature on this issue. Attention is drawn to the application of this concept to procedural institutions of various contents (expert opinion and opinion in accordance with Articles 45 and 47 of the Civil Procedure Code of the Russian Federation). The aim of the study is to establish the content of the general concept of «conclusion» in the civil process by formulating its definition. To achieve this goal, the author has set the task of identifying differences between different types of conclusions in the civil process. The author also set the task of identifying common features that both expert opinions and conclusions have in accordance with Articles 45 and 47 of the Civil Procedure Code of the Russian Federation. In the framework of this study, methods such as the analysis method, as well as system-structural and formal-legal methods were applied. The content of the procedural rules in their totality and comparison, including the norms of other procedural branches of law, is analyzed. The application of the above methods allowed us to fully achieve the goals and objectives of the study, to formulate scientifically based conclusions. Based on the results of the study, the author gives a general definition of the concept of «conclusion» in civil procedure law, applicable to all types of opinions that exist within the framework of the norms of the Civil Procedure Code of the Russian Federation. Attention is drawn to the nature of the conclusion as a judgment of an evaluative nature. As signs of a conclusion in a civil process, its subject (the subject of civil process) and a specific procedural form are named.

SCIENTIFIC APPROACHES TO THE DEFINITION OF THE TERM "CRITICAL INFRASTRUCTURE"

2020 ◽  
pp. 184-193
Author(s):  
Inga Uriadnikova ◽  
◽  
Vasyl Zaplatynskyi ◽  
Keyword(s):  
Critical Infrastructure ◽  
Soft Soil ◽  
Social Systems ◽  
Technical Information ◽  
Social Engineering ◽  
General Concept ◽  
Practical Significance ◽  
General Definition ◽  
Definition Of ◽  
Common Understanding

Purpose: scientific substantiation of the concept of “critical infrastructure” based on research of definitions of “infrastructure” and “critical” and comparison of definitions that are widely used in different countries. Methodology: analysis of the content of the concept of “critical infrastructure”, based on the content of the basic terms “infrastructure” and “critical”, analysis of the concept of “critical infrastructure” in laws and regulations of different countries and logical-determinative assessment of these concepts. Results: the general concept of “critical infrastructure” is substantiated – physical and virtual systems, objects and resources – the destruction, destruction or reduction of capacity of which will lead to significant threats to the country (region or city), its national security, life and health. A common understanding of this concept is important in the context of growing and diversifying threats and increasing the complexity of technical, information and social systems, when there is a growing need to protect the basic, ie critical parts of these systems, without which they can not function. Based on the analysis of existing concepts used in regulations and legislation of different countries, as well as scientific approaches of different authors, the main logical characteristics of this concept are identified, and based on the synthesis formed a generalized concept of “critical infrastructure”, which can be the basis for formulating derivatives such as social critical infrastructure, critical engineering infrastructure, etc. Scientific novelty: On the basis of numerical modeling the regularities of stress distribution in rocks under detached rock packs of different shapes have been investigated, which allowed substantiating the parameters of the last and compensatory voids between them to ensure the stability of workings in the soft soil rocks. Scientific novelty: on the basis of comparative analysis the characteristic features of the concept of “critical infrastructure” are singled out, a variable number of definitions of “critical” and “infrastructure” is analyzed, and a general definition of this concept is proposed, which provides a common understanding and can be used. Practical significance: the formulated definition of the concept of “critical infrastructure” will allow the unification of this concept in the scientific field, legislation and regulations. It will allow to formulate derivatives of this concept, in particular, transport, military, social, engineering infrastructure on uniform methodological approaches.

Comparison of Fluorine(18)-fluorodeoxyglucose and Gallium(68)-citrate PET/CT in patients with tuberculosis

2019 ◽  
Vol 58 (05) ◽  
pp. 371-378
Author(s):  
Alfred O. Ankrah ◽  
Ismaheel O. Lawal ◽  
Tebatso M.G. Boshomane ◽  
Hans C. Klein ◽  
Thomas Ebenhan ◽  
...  
Keyword(s):  
Tracer Uptake ◽  
Pet Ct ◽  
The Mean ◽  
18F Fdg ◽  
Definition Of ◽  
Gallium 68 ◽  
Attending Physician ◽  
Pet Scans ◽  
The Brain

Abstract 18F-FDG and 68Ga-citrate PET/CT have both been shown to be useful in the management of tuberculosis (TB). We compared the abnormal PET findings of 18F-FDG- and 68Ga-citrate-PET/CT in patients with TB. Methods Patients with TB on anti-TB therapy were included. Patients had a set of PET scans consisting of both 18F-FDG and 68Ga-citrate. Abnormal lesions were identified, and the two sets of scans were compared. The scan findings were correlated to the clinical data as provided by the attending physician. Results 46 PET/CT scans were performed in 18 patients, 11 (61 %) were female, and the mean age was 35.7 ± 13.5 years. Five patients also had both studies for follow-up reasons during the use of anti-TB therapy. Thirteen patients were co-infected with HIV. 18F-FDG detected more lesions than 68Ga-citrate (261 vs. 166, p < 0.0001). 68Ga-citrate showed a better definition of intracerebral lesions due to the absence of tracer uptake in the brain. The mean SUVmax was higher for 18F-FDG compared to 68Ga-citrate (5.73 vs. 3.01, p < 0.0001). We found a significant correlation between the SUVmax of lesions that were determined by both tracers (r = 0.4968, p < 0.0001). Conclusion Preliminary data shows 18F-FDG-PET detects more abnormal lesions in TB compared to 68Ga-citrate. However, 68Ga-citrate has better lesion definition in the brain and is therefore especially useful when intracranial TB is suspected.

Simultaneous heat and mass transfer during evaporation from a film of liquid into the turbulent gas

1982 ◽  
Vol 47 (3) ◽  
pp. 766-775 ◽  
Author(s):  
Václav Kolář ◽  
Jan Červenka
Keyword(s):  
Experimental Data ◽  
Mass Transfer ◽  
Liquid Film ◽  
Heat And Mass Transfer ◽  
Driving Forces ◽  
Proper Definition ◽  
Definition Of ◽  
Simultaneous Heat ◽  
Theory And Experiment

The paper presents results obtained by processing a series of published experimental data on heat and mass transfer during evaporation of pure liquids from the free board of a liquid film into the turbulent gas phone. The data has been processed on the basis of the earlier theory of mechanism of heat and mass transfer. In spite of the fact that this process exhibits a strong Stefan's flow, the results indicate that with a proper definition of the driving forces the agreement between theory and experiment is very good.

scholarly journals Modeling the Excess Velocity of Low-Viscous Taylor Droplets in Square Microchannels

Fluids ◽  
2019 ◽  
Vol 4 (3) ◽  
pp. 162 ◽  
Author(s):  
Thorben Helmers ◽  
Philip Kemper ◽  
Jorg Thöming ◽  
Ulrich Mießner
Keyword(s):  
High Speed ◽  
Process Intensification ◽  
Continuous Phase ◽  
Channel Cross Section ◽  
Optimization Approach ◽  
Mean Flow ◽  
Bypass Flow ◽  
Wall Film ◽  
Proposed Model ◽  
The Mean

Microscopic multiphase flows have gained broad interest due to their capability to transfer processes into new operational windows and achieving significant process intensification. However, the hydrodynamic behavior of Taylor droplets is not yet entirely understood. In this work, we introduce a model to determine the excess velocity of Taylor droplets in square microchannels. This velocity difference between the droplet and the total superficial velocity of the flow has a direct influence on the droplet residence time and is linked to the pressure drop. Since the droplet does not occupy the entire channel cross-section, it enables the continuous phase to bypass the droplet through the corners. A consideration of the continuity equation generally relates the excess velocity to the mean flow velocity. We base the quantification of the bypass flow on a correlation for the droplet cap deformation from its static shape. The cap deformation reveals the forces of the flowing liquids exerted onto the interface and allows estimating the local driving pressure gradient for the bypass flow. The characterizing parameters are identified as the bypass length, the wall film thickness, the viscosity ratio between both phases and the C a number. The proposed model is adapted with a stochastic, metaheuristic optimization approach based on genetic algorithms. In addition, our model was successfully verified with high-speed camera measurements and published empirical data.

scholarly journals A remark on local fractional calculus and ordinary derivatives

2016 ◽  
Vol 14 (1) ◽  
pp. 1122-1124 ◽  
Author(s):  
Ricardo Almeida ◽  
Małgorzata Guzowska ◽  
Tatiana Odzijewicz
Keyword(s):  
Fractional Calculus ◽  
Fractional Derivative ◽  
Short Note ◽  
General Definition ◽  
Local Fractional Derivative ◽  
Fundamental Properties ◽  
Local Fractional Calculus ◽  
Definition Of

AbstractIn this short note we present a new general definition of local fractional derivative, that depends on an unknown kernel. For some appropriate choices of the kernel we obtain some known cases. We establish a relation between this new concept and ordinary differentiation. Using such formula, most of the fundamental properties of the fractional derivative can be derived directly.

Non-isothermal crystallization behavior of spinel crystals in FeO-SiO2-TiO2-V2O3-Cr2O3 slag

2018 ◽  
Vol 116 (1) ◽  
pp. 110
Author(s):  
Lixiong Shao ◽  
Jiang Diao ◽  
Wang Zhou ◽  
Tao Zhang ◽  
Bing Xie
Keyword(s):  
Cooling Rate ◽  
Crystallization Behavior ◽  
Crystal Size ◽  
Growth Mechanisms ◽  
Vanadium Slag ◽  
Growth Behaviour ◽  
Temperature Range ◽  
Chromium Spinel ◽  
Mean Diameter ◽  
The Mean

The growth behaviour of spinel crystals in vanadium slag with high Cr2O3 content was investigated and clarified by statistical analyses based on the Crystal Size Distribution (CSD) theory. The results indicate that low cooling rate and Cr2O3 content benefit the growth of spinel crystals. The chromium spinel crystals firstly precipitated and then acted as the heterogeneous nuclei of vanadium and titanium spinel crystals. The growth mechanisms of the spinel crystals at the cooling rate of 5 K/min consist two regimes: firstly, nucleation control in the temperature range of 1873 to 1773 K, in which the shapes of CSD curves are asymptotic; secondly, surface and supply control within the temperature range of 1773 to 1473 K, in which the shapes of CSD curves are lognormal. The mean diameter of spinel crystals increases from 3.97 to 52.21 µm with the decrease of temperature from 1873 to 1473 K.

scholarly journals AB0677 REVISING THE DEFINITION OF REACTIVE ARTHRITIS AND DIFFERENTIATION FROM UNDIFFERENTIATED SPONDYLOARTHRITIS

2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 1633.2-1634
Author(s):  
F. Cosan ◽  
O. M. Gedar
Keyword(s):  
Causative Agent ◽  
Reactive Arthritis ◽  
Case Reports ◽  
Experimental Studies ◽  
Classification Criteria ◽  
General Definition ◽  
Parasitic Infections ◽  
Undifferentiated Spondyloarthritis ◽  
Classical Definition ◽  
Definition Of

Background:Reactive arthritis (ReA) is defined by 1999 ACR criteria as arthritis preceding a bacterial genitourinary (GUS) or gastrointestinal (GIS) infection in 3 days-6 weeks and evidence of triggering infection. Recently, ReA is classified as SpA and patients who do not fulfill SpA criteria are classified as undifferentiated spondyloarthritis (USpA) according to ASAS/EULAR SpA classification criteria.Objectives:In several case reports which are associated with other infective agents are reported and the definition is extended for some clinicians so that SpA which is occurred after any infection is called as ReA. On the other hand, some researchers still accept the classical definition of ReA. The problem with the heterogeneity of opinions and unstandardized definition of ReA hinders studies about pathogenesis and standardization of treatments. In this study, we aimed to determine the spectrum of the use of the definition of reactive arthritis in publications in PubMed between 2009-2019.Methods:The ReA keyword is searched in PubMed for the years between 2009-2019. 248 different publications have been identified and included in this research. 89 articles, 47 reviews, 108 case reports, 2 guidelines, and 2 editorials reviewed for the definition of ReA.Results:Only 42.7% (106 patients) of these publications meet the classical definition which suggests ReA after only GIS and GUS infections. In 4 (1.6%) of the publications ReA was defined after GIS, GUS and oropharyngeal infections; in 3 (1,2%) of the publications after any bacterial infection; in 9 (3.6%) of the publications after any infection. In 8 (3.2%) of the publications, ReA and USPA was used correspondingly. In 39 (15,7%) of the publications the term agent related, ReA was used without making a general definition for ReA. 79 publications (31,9%) have not defined ReA.According to causative agent and ReA relationship, in 64 (24,6%) general infective agents, in 75 (30,2%) classical agents, in 22 (8,9%) other bacterial agents, in 23 (9,3%) streptococcus, in 10(4%) intravesical BCG, in 6 (2.4%) HIV, in 6 (2.4%) tuberculosis, in 12 (4,8%) clostrudium difficle, in 2 (0.8%) parasites were reported. In 31 (12,5%) of the publications the causative agent for the ReA was unknown, the diagnosis was made clinically.Conclusion:In this study, it is aimed to draw attention terminology intricacy and the need for the standardization of the definition of ReA and USpA. It is clear that to standardize the definition of Rea and USpA is necessary. Between 2009-2019 there are reported cases diagnosed as ReA associated with bacterial infections (especially with Clostridium difficile, streptococcus and tuberculosis infections), and viral infections (by a majority with HIV), and parasitic infections. It is not clear if we need to define them classically or define them as USPA. Another important consideration is the necessity of extended laboratory investigations to find out the real causative agent even if the patient is clinically diagnosed with ReA. The requirement of the differentiation between ReA and USpA must be revealed for therapeutic researches.References:[1]A proposal for the classification of patients for clinical and experimental studies on reactive arthritis. Pacheco-Tena C, Burgos-Vargas R, Vázquez-Mellado J, Cazarín J, Pérez-Díaz JA. J Rheumatol. 1999 Jun;26(6):1338-46.[2]The Assessment of SpondyloArthritis International Society classification criteria for peripheral spondyloarthritis and for spondyloarthritis in general. Rudwaleit M, van der Heijde D, Landewé R, Akkoc N, Brandt J, Chou CT, Dougados M, Huang F, Gu J, Kirazli Y, et al. Ann Rheum Dis. 2011;70:25–31.Disclosure of Interests:None declared

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