scholarly journals On the Use of the Analogue Transformation Acoustics in Aeroacoustics

2017 ◽  
Vol 2017 ◽  
pp. 1-16 ◽  
Author(s):  
Umberto Iemma ◽  
Giorgio Palma
Keyword(s):  
Velocity Field ◽  
Fluid Dynamic ◽  
Conformal Mappings ◽  
Governing Equations ◽  
Realistic Potential ◽  
Moving Media ◽  
Analytical Tools ◽  
The Relationship ◽  
Dynamic Conservation ◽  
Transformation Acoustics

The objective of the paper is the assessment of the Analogue Transformation Acoustics (ATA) in the design of acoustic metamaterial for aeronautical applications. The work focuses on the consistency of the background flow resulting from the application of the ATA with the equations governing the potential aerodynamics. Indeed, in case of acoustic perturbations propagating within moving media, the convective terms in the governing equations are responsible for the failure of formal invariance under the action of conformal mappings. The ATA approach overcomes this limitation, introducing the possibility of handling the convective form of the wave equation in a straightforward and elegant way. It is based on the concept of analogue space-time and fully relies on the analytical tools of Lorentzian differential geometry. The present paper analyses the relationship between the analogue velocity field with a realistic potential flow. The method is validated through numerical simulations using two widely assessed acoustic cloaking problems. The preliminary results obtained show that the use of numerical, quasi-conformal mappings can lead to transformed streamlines negligibly deviating from those of the potential velocity field satisfying the fluid-dynamic conservation laws, but with incompatible intensity of the local velocity.

War Widows and Welfare Queens

2019 ◽  
pp. 584-605
Author(s):  
Brittany Pearl Battle
Keyword(s):  
Policy Development ◽  
Social Welfare Policy ◽  
Cultural Representations ◽  
The Poor ◽  
The Social ◽  
The Family ◽  
Deserving Poor ◽  
Analytical Tools ◽  
The Relationship ◽  
Undeserving Poor

This chapter examines the sociocognitive dimensions of cultural categorizations of deservingness. The social issue of poverty has been a persistent source of debate in the American system of policy development, influenced by conceptual distinctions between the “haves” and “have-nots,” “working moms” and “unemployed dads,” and the “deserving poor” and the “undeserving poor.” Although there is a wealth of literature discussing the ideological underpinnings of stratification systems, these discussions often focus on categorical distinctions between the poor and the nonpoor, with much less discussion of distinctions made among the poor. Moreover, while scholars of culture and policy have long referenced the importance of cultural categories of worthiness in policy development, the theoretical significance of these distinctions has been largely understudied. I expand the discourse on the relationship between cultural representations of worth and social welfare policy by exploring how these categories are conceptualized. Drawing on analytical tools from a sociology of perception framework, I create a model that examines deservingness along continuums of morality and eligibility to highlight the taken-for-granted cultural subtleties that shape perceptions of the poor. I focus on social filters created by norms of poverty, welfare, and the family to explore how the deserving are differentiated from the undeserving.

Flow recirculation zone length and shear rate are differentially affected by stenosis severity in human coronary arteries

2013 ◽  
Vol 304 (4) ◽  
pp. H559-H566 ◽  
Author(s):  
Ashkan Javadzadegan ◽  
Andy S. C. Yong ◽  
Michael Chang ◽  
Austin C. C. Ng ◽  
John Yiannikas ◽  
...  
Keyword(s):  
Shear Rate ◽  
Coronary Arteries ◽  
Recirculation Zone ◽  
Fluid Dynamic ◽  
Zone Length ◽  
Flow Recirculation ◽  
Stenosis Severity ◽  
Recirculation Zones ◽  
The Relationship

Flow recirculation zones and shear rate are associated with distinct pathogenic biological pathways relevant to thrombosis and atherogenesis. The interaction between stenosis severity and lesion eccentricity in determining the length of flow recirculation zones and peak shear rate in human coronary arteries in vivo is unclear. Computational fluid dynamic simulations were performed under resting and hyperemic conditions on computer-generated models and three-dimensional (3-D) reconstructions of coronary arteriograms of 25 patients. Boundary conditions for 3-D reconstructions simulations were obtained by direct measurements using a pressure-temperature sensor guidewire. In the computer-generated models, stenosis severity and lesion eccentricity were strongly associated with recirculation zone length and maximum shear rate. In the 3-D reconstructions, eccentricity increased recirculation zone length and shear rate when lesions of the same stenosis severity were compared. However, across the whole population of coronary lesions, eccentricity did not correlate with recirculation zone length or shear rate ( P = not signficant for both), whereas stenosis severity correlated strongly with both parameters ( r = 0.97, P < 0.001, and r = 0.96, P < 0.001, respectively). Nonlinear regression analyses demonstrated that the relationship between stenosis severity and peak shear was exponential, whereas the relationship between stenosis severity and recirculation zone length was sigmoidal, with an apparent threshold effect, demonstrating a steep increase in recirculation zone length between 40% and 60% diameter stenosis. Increasing stenosis severity and lesion eccentricity can both increase flow recirculation and shear rate in human coronary arteries. Flow recirculation is much more sensitive to mild changes in the severity of intermediate stenoses than is peak shear.

Capacity Constraints and Horizontal Merger Effects

2018 ◽  
Vol 63 (4) ◽  
pp. 444-454
Author(s):  
Jay Ezrielev
Keyword(s):  
Binding Capacity ◽  
Market Concentration ◽  
Capacity Constraints ◽  
Market Definition ◽  
Horizontal Merger ◽  
Horizontal Mergers ◽  
Price Effects ◽  
Analytical Tools ◽  
The Relationship ◽  
Merger Simulation

This article examines how capacity constraints affect horizontal mergers. Binding capacity constraints for merging firms may mitigate merger price effects, but capacity constraints for nonmerging firms may either amplify or mitigate such effects. The presence of capacity constraints for both the merging and nonmerging firms in a market further complicates the analysis of merger price effects. Capacity constraints may also confound the relationship between market concentration and merger price effects. In addition, capacity constraints affect market definition analysis and analytical tools such as merger simulation and upward pricing pressure indexes. Analyzing the effects of capacity constraints on mergers continues to be a challenge for merger reviews.

scholarly journals Observations of magnetic and kinetic helicity proxies

2012 ◽  
Vol 8 (S294) ◽  
pp. 13-24
Author(s):  
Hongqi Zhang
Keyword(s):  
Magnetic Field ◽  
Velocity Field ◽  
Magnetic Fields ◽  
Solar Atmosphere ◽  
Active Regions ◽  
Solar Dynamo ◽  
Magnetic Helicity ◽  
Vector Magnetograms ◽  
Topological Configuration ◽  
The Relationship

AbstractThe helicity is important to present the basic topological configuration of magnetic field in solar atmosphere. The distribution of magnetic helicity in solar atmosphere is presented by means of the observational (vector) magnetograms. As the kinetic helicity in the solar subatmosphere can be inferred from the velocity field based on the technique of the helioseismology and used to compare with the magnetic helicity in the solar atmosphere, the observational helicities provide the important chance for the confirmation on the generation of magnetic fields in the subatmosphere and solar dynamo models also. In this paper, we present the observational magnetic and kinetic helicity in solar active regions and corresponding questions, except the relationship with solar eruptive phenomena.

scholarly journals Human Resource Management Of Bureaucracy In Indonesia: Is It True That Job Satisfaction Increases Employee Performance ?

2021 ◽  
Vol 58 (1) ◽  
pp. 3218-3231
Author(s):  
Meimoon Ibrahim, Ilyas Lamuda
Keyword(s):  
Job Satisfaction ◽  
Leadership Style ◽  
Structural Equation ◽  
Employee Performance ◽  
Provincial Government ◽  
Equation Modeling ◽  
Critical Ratio ◽  
Relationship Of ◽  
Analytical Tools ◽  
The Relationship

Objective: This study aims to analyze how the effect of leadership variables on employee performance with job satisfaction as intervening in the provincial government of Gorontalo-Indonesia. Methods: The approach used is explanatory research, pattern of research that seeks to explain the relationship of variables referred so that the relationship of these variables can be tested with a quantitative approach and hypothesis testing used is the method of Structural Equation Modeling, with analytical tools of Loading Factor and Critical Ratio which is preceded by a validity test and reliability test.  The sample was drawn randomly according to representative samples at the level of the position group as many as 5% employee population of the Provincial it. Results ;The results of the study show that leadership style has a positive and significant influence on job satisfaction and leadership style has an effect on employees' performance, but job satisfaction has negative and non-significant effect on employee performance. Conclusion; Expected that this research could also be developed in other fields or a wider scope and not only because each region has different characteristics. So it is recommended that policy makers as bureaucratic managers to pay more attention to job satisfaction factors in order to further improve employee performance.

scholarly journals The effect analysis of mediation variable of task productivity on the self-efficacy and employees’ performance

2016 ◽  
Vol 19 (2) ◽  
pp. 237
Author(s):  
Annissa Chairum Soebandono ◽  
Levi Nilawati
Keyword(s):  
Self Efficacy ◽  
High Performance ◽  
Sampling Method ◽  
The Self ◽  
Effect Analysis ◽  
Individual Task ◽  
Convenience Sampling ◽  
Analytical Tools ◽  
The Relationship ◽  
Mediation Models

This research was conducted for analyzing the effect of mediating variable that is individual task proactivity as one of the proactivities of behavior towards the relationship between self-efficacy and the employees’ performance in the logistics companies of shipping the goods. It uses convenience sampling, which is a non-probability sampling method for getting the sample of 52 employees. They were divided into two divisions, namely infrastructure and quality assurance. The questionnaire consists of two parts, in which some were assessed by themselves and others that were assessed by the supervisor. They were analyzed using path analysis using analytical tools developed by Hayes, Preacher-Hayes with the simple mediation models. It was found that employees have self-efficacy, individual task proactivity, and relatively high performance, in which individual task proactivity can be a mediating variable on the effect self-efficacy on performance.

On Assessing the Quality of Particle Tracking Through Computational Fluid Dynamic Models

2002 ◽  
Vol 124 (2) ◽  
pp. 166-175 ◽  
Author(s):  
Mauro Tambasco ◽  
David A. Steinman
Keyword(s):  
Velocity Field ◽  
Computational Fluid Dynamic ◽  
Particle Deposition ◽  
Dynamic Models ◽  
Fluid Dynamic ◽  
Mass Conservation ◽  
Carotid Bifurcation ◽  
Quantitative Information ◽  
Flow Models ◽  
Path Dependent

Quantification of particle deposition patterns, transit times, and shear exposure is important for computational fluid dynamic (CFD) studies involving respiratory and arterial models. To numerically compute such path-dependent quantities, it is necessary to employ a Lagrangian approach where particles are tracked through a pre-computed velocity field. However, it is difficult to determine in advance whether a particular velocity field is sufficiently resolved for the purposes of tracking particles accurately. Towards this end, we propose the use of volumetric residence time (VRT)—previously defined for 2-D studies of platelet activation and here extended to more physiologically relevant 3-D models—as a means of quantifying whether a volume of Lagrangian fluid elements (LFE’s) seeded uniformly and contiguously at the model inlet remains uniform throughout the flow domain. Such “Lagrangian mass conservation” is shown to be satisfied when VRT=1 throughout the model domain. To demonstrate this novel concept, we computed maps of VRT and particle deposition in 3-D steady flow models of a stenosed carotid bifurcation constructed with one adaptively refined and three nominally uniform finite element meshes of increasing element density. A key finding was that uniform VRT could not be achieved for even the most resolved meshes and densest LFE seeding, suggesting that care should be taken when extracting quantitative information about path-dependent quantities. The VRT maps were found to be useful for identifying regions of a mesh that were under-resolved for such Lagrangian studies, and for guiding the construction of more adequately resolved meshes.

American Political Development from Citizens' Perspective: Tracking Federal Government's Presence in Individual Lives over Time

2007 ◽  
Vol 21 (1) ◽  
pp. 110-130 ◽  
Author(s):  
Suzanne Mettler ◽  
Andrew Milstein
Keyword(s):  
Political Development ◽  
American Political Development ◽  
State Building ◽  
The State ◽  
The Political ◽  
Quarter Century ◽  
Political Roles ◽  
Analytical Tools ◽  
The Relationship ◽  
Over Time

Although scholars of American political development (APD) have helped transform many aspects of the study of U.S. politics over the last quarter-century, they have barely begun to use the powerful analytical tools of this approach to elucidate the relationship between government and citizens. APD research has probed deeply into the processes of state-building and the creation and implementation of specific policies, yet has given little attention to how such development affects the lives of individuals and the ways in which they relate to government. Studies routinely illuminate how policies influence the political roles of elites and organized groups, but barely touch on how the state shapes the experiences and responses of ordinary individuals. As a result, we know little about how governance has influenced citizenship over time or how those changes have, in turn, affected politics.

COMPUTATIONAL FLUID DYNAMIC ANALYSIS OF COUNTERFLOW TURBULENT PREMIXED FLAMES BY THE COHERENT FLAMELET MODEL

2000 ◽  
Vol 24 (1A) ◽  
pp. 33-44
Author(s):  
E. Lee ◽  
K.Y. Huh
Keyword(s):  
Source Term ◽  
Fluid Dynamic ◽  
Burning Velocity ◽  
Premixed Flames ◽  
Turbulent Premixed Flames ◽  
Computational Fluid Dynamic Analysis ◽  
Flamelet Model ◽  
Turbulent Burning Velocity ◽  
The Relationship ◽  
Turbulent Premixed

The Coherent Flamelet Model (CFM) is applied to symmetric counterflow turbulent premixed flames studied by Kostiuk et al. The flame source term is set proportional to the sum of the mean and turbulent rate of strain while flame quenching is modeled by an additional multiplication factor to the flame source term. The turbulent rate of strain is set proportional to the turbulent intensity to match the correlation for the turbulent burning velocity investigated by Abdel-Gayed et al. The predicted flame position and turbulent flow field coincide well with the experimental observations. The relationship between the Reynolds averaged reaction progress variable and flame density seems to show a wrong trend due to inappropriate modeling of the sink and source term in the transport equation.

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