scholarly journals Colour Doppler Spatial Resolution Performance Testing

Ultrasound ◽  
2007 ◽  
Vol 15 (3) ◽  
pp. 162-166 ◽  
Author(s):  
Jacinta E Browne ◽  
Ian Brown ◽  
Peter R Hoskins ◽  
Amanda J Watson ◽  
Alex T Elliott
Keyword(s):  
Spatial Resolution ◽  
Performance Testing ◽  
Colour Doppler ◽  
Advantages And Disadvantages ◽  
Array Transducer ◽  
Flow Phantom ◽  
Minimum Separation ◽  
Set Up ◽  
Test Phantom ◽  
Continuous Range

Background: Colour Doppler has become an integral part of many clinical ultrasound investigations, but evaluation of the spatial resolution of colour Doppler scanners remains problematic due to a lack of suitable test phantoms. Methods: The aims of this study were to evaluate two designs of colour Doppler spatial resolution test-phantom to compare their suitability for determining the spatial resolution of five commercially available ultrasound scanners. For the purpose of this study, spatial resolution was defined as the minimum resolvable distance between two channels of flow. Phantom 1 consisted of two diverging flow-channels. Phantom 2 consisted of four pairs of parallel channels with different separations. Results and Discussion: Both designs of phantom highlighted a number of advantages and disadvantages. In principle, phantom 1 allowed the minimal resolvable distance to be identified based on imaging a continuous range of separations, but in practice, the average separation being probed was uncertain, and the minimum separation between vessels of 1 mm was too large to test the resolutions of some of the scanners we studied. Phantom 2 was easier to set up and had a narrower minimum separation of 0.6 mm, but only four nominal separations were tested. Evaluation of five scanners using each prototype phantom suggested typical resolutions of 1·2 mm or lower. Many of the scanners possessed resolutions of approximately 0.6 mm or less, which was the minimum separation we were able to test. The poorest lateral resolution of approximately 1·2 mm was observed for a 13 year old scanner with curvilinear 4 MHz phased array transducer. Conclusion: Construction of the 'perfect' test-object for measuring colour Doppler resolution remains a considerable challenge. Further work will be required to produce acoustically realistic flow phantoms capable of testing the ability of colour Doppler to resolve increasingly narrow flow separations.

scholarly journals Simulations of disks in binary systems using parallelized SPH to reach extreme spatial resolution

2003 ◽  
Vol 208 ◽  
pp. 427-428
Author(s):  
D. Molteni ◽  
F. Fauci ◽  
G. Gerardi ◽  
M. A. Valenza
Keyword(s):  
Black Hole ◽  
Angular Momentum ◽  
Numerical Simulations ◽  
Spatial Resolution ◽  
Spectral Properties ◽  
Binary Systems ◽  
Compact Star ◽  
Close Binary ◽  
Gas Transfer ◽  
Set Up

Results of 3D numerical simulations of the gas transfer in close binary systems show that it is possible the production of accretion streams having low specific angular momentum in a region close to the accreting star. These streams are mainly placed above the orbital disc. The eventual formation of such bulges and shock heated flows is interesting in the context of advection dominated solutions and for the explanation of spectral properties of the Black Hole candidates in binary systems. We set up a parallelized version of 3D S.P.H. code, using domain decomposion. with increasing spatial resolution around the compact star.

Perceived Advantages and Disadvantages of Nonsmoking Sections in Restaurants: Topics to Communicate to Restaurateurs

1989 ◽  
Vol 9 (4) ◽  
pp. 299-304 ◽  
Author(s):  
Gerardo Marin ◽  
Raymond J. Gamba
Keyword(s):  
San Francisco ◽  
Advantages And Disadvantages ◽  
Set Up

Results from interviews with 315 restaurateurs in San Francisco are reported on their perceptions of the advantages and disadvantages of having a nonsmoking section in their restaurants. The major advantage of having a nonsmoking section independent of whether one is present is to please customers. The most commonly mentioned disadvantage for those restaurants with nonsmoking sections is the fact that it is inconvenient to clients' seating preferences primarily because it breaks up dining parties. Efforts at convincing restaurateurs to set up nonsmoking sections may be directed at pointing out savings in cleaning, labor, insurance, and the improvement of the health of their employees together with meeting clients' desires.

scholarly journals Compartimentação dos elementos do relevo da bacia hidrográfica do arroio Pantanoso – Canguçu/RS, através da proposta dos geomorphons

2020 ◽  
Vol 13 (2) ◽  
pp. 713
Author(s):  
Danilo Da Silva Dutra ◽  
André Ricardo Furlan ◽  
Luís Eduardo De Souza Robaina
Keyword(s):  
Digital Elevation Model ◽  
River Basin ◽  
Spatial Resolution ◽  
Advantages And Disadvantages ◽  
Digital Elevation ◽  
Relief Elements ◽  
Gis Environment ◽  
Elevation Model

O relevo é a base onde todas as populações vivem e desenvolvem suas atividades, derivando dessa relação vantagens e desvantagens, daí a importância de conhecê-lo através do estudo de suas diferentes formas e elementos. Nesse contexto insere-se a importância de metodologias para o seu estudo, sendo que atualmente vivencia-se a expressividade de dados disponíveis para aplicação de geoprocessamento. A partir das geotecnologias pode-se empreender diversas análises sobre o relevo, destacando-se nesse contexto, a proposta dos geomorphons a qual foi aplicada na bacia hidrográfica do arroio Pantanoso. O objetivo da pesquisa é a identificação e análise dos elementos do relevo definido por geomorphons, quais sejam: 1) Planos, 2) Picos, 3) Cristas, 4) Ressaltos, 5) Crista secundária, 6) Encostas, 7) Escavado, 8) Base de encosta, 9) Vales e 10) Fosso. A determinação dos geomorphons foi a partir do processamento em ambiente SIG do Modelo Digital de Elevação (MDE) do Shuttle Radar Topograph Mission (SRTM) com resolução espacial 3 arcsec (90 metros), “L” Lookup (distância em metros) definiu-se como de 20 pixels (1800 metros) e o “T” Theresholdt (nivelamento em graus) definiu-se em 2º. Para visualização do comportamento dos elementos do relevo na área de estudo realizaram-se trabalhos de campo, o que contribuiu para evidenciar a padronização desses elementos. Os quatro elementos geomorphons mais representativos são encostas, vales, cristas e planos. Subdivision of relief elements through the proposal of geomorphons: river basin of arroio Pantanoso - Canguçu/RS A B S T R A C TRelief is the basis where all populations live and develop their activities, deriving from this relation advantages and disadvantages, hence the importance of knowing it through the study of its different forms and elements. In this context, the importance of methodologies for its study is inserted and geoprocessing application for data available for is currently experienced. From the geotechnologies one can undertake several analyzes on the relief, highlighting in this context, the proposal of the geomorphons which was applied in Pantanoso stream basin. The objective of the research is to identify and analyze the elements of the relief defined by geomorphons, namely: 1) Flats, 2) Peaks, 3) Ridges, 4) Shoulders, 5) Spurs, 6)Slopes, 7) Hollows, 8) Footslope, 9) Valley and 10) Pits. The determination of the geomorphons was based on the GIS environment of the Shuttle Radar Topograph Mission (SRTM) Digital Elevation Model (DEM) with spatial resolution 3 arcsec (90 meters), "L" Lookup (distance in meters) was defined as of 20 pixels (1800 meters) and the "T" Theresholdt (leveling in degrees) was defined in 2º. In order to visualize the behavior of the relief elements in the study area, fieldwork was carried out, which contributed to the standardization of these elements. The four most representative geomorphons, which are: Slopes, Valleys, Ridges and Flat.Keywords: SIG, Geomorphons; Canguçu/RS; relief

CLASSIFICATION OF HAND SPLINTING

Hand Surgery ◽  
2002 ◽  
Vol 07 (02) ◽  
pp. 209-213 ◽  
Author(s):  
Simon K. M. Wong
Keyword(s):  
Environmental Factors ◽  
Classification System ◽  
Single System ◽  
Logical Deduction ◽  
Advantages And Disadvantages ◽  
American Society ◽  
Set Up ◽  
New System ◽  
Rote Memory

The terminology in describing splint or orthosis has been reviewed but there is no one single system adopted universally. Joint efforts by doctors, therapists and orthotists had been set up to review the classification of splint. Four ways of classifying hand splints have been introduced: namely, eponym, acronym, descriptive classification system and the classification system proposed by the American Society of Hand Therapists. These systems include the use of rote memory or logical deduction in grouping of splints. This paper describes the advantages and disadvantages of each classification system. Neither one of the systems stands out to be the best. A combination of the advantages of different systems, such as precision and logical deduction, may be an option for developing a new system. Moreover, communication, documentation and other environmental factors should also be considered.

Beak Trimming Handbook for Egg Producers

2006 ◽  
Author(s):  
Phil Glatz ◽  
Michael Bourke
Keyword(s):  
Quality Control ◽  
Best Practice ◽  
Egg Laying ◽  
Advantages And Disadvantages ◽  
Future Developments ◽  
Maximum Productivity ◽  
Comprehensive Information ◽  
Set Up ◽  
Beak Trimming ◽  
Farm Biosecurity

The Beak Trimming Handbook for Egg Producers is a straightforward, practical guide to beak trimming of egg-laying hens to minimise cannibalism. It provides comprehensive information on why birds peck and how pecking can lead to problems like cannibalism; the methods available to beak trim birds; why a particular method should be chosen; and at what age birds may be trimmed. The book addresses quality control of beak trimming, enabling egg producers to be confident that equipment is properly set up, that birds are handled and trimmed according to best practice and farm biosecurity is maintained. Management of birds following beak trimming, to protect of the welfare of the birds and to ensure maximum productivity, is covered in detail. Best-practice, current methods of beak trimming, costs of trimming and ways to reduce the use of trimming are examined, along with expected future developments. The advantages and disadvantages of beak trimming are fully explored, covering both public and industry attitudes to the operation. Alternatives to beak trimming are canvassed to understand how the use of fitted devices, enrichment devices, abrasives, low lighting and the choice of low-pecking strains of birds can reduce the need for beak trimming. Finally, the book discusses strategies for minimising cannibalism and how the chosen strategy may be documented and justified. Please note that this book is spiral-bound.

scholarly journals Defining a Trade-off Between Spatial and Temporal Resolution of a Geosynchronous SAR Mission for Soil Moisture Monitoring

2018 ◽  
Vol 10 (12) ◽  
pp. 1950 ◽  
Author(s):  
Luca Cenci ◽  
Luca Pulvirenti ◽  
Giorgio Boni ◽  
Nazzareno Pierdicca
Keyword(s):  
Soil Moisture ◽  
Spatial Resolution ◽  
Temporal Resolution ◽  
Added Value ◽  
Sar Images ◽  
Radar Images ◽  
Spatio Temporal ◽  
Set Up ◽  
The Impact ◽  
Hydrological Applications

The next generation of synthetic aperture radar (SAR) systems could foresee satellite missions based on a geosynchronous orbit (GEO SAR). These systems are able to provide radar images with an unprecedented combination of spatial (≤1 km) and temporal (≤12 h) resolutions. This paper investigates the GEO SAR potentialities for soil moisture (SM) mapping finalized to hydrological applications, and defines the best compromise, in terms of image spatio-temporal resolution, for SM monitoring. A synthetic soil moisture–data assimilation (SM-DA) experiment was thus set up to evaluate the impact of the hydrological assimilation of different GEO SAR-like SM products, characterized by diverse spatio-temporal resolutions. The experiment was also designed to understand if GEO SAR-like SM maps could provide an added value with respect to SM products retrieved from SAR images acquired from satellites flying on a quasi-polar orbit, like Sentinel-1 (POLAR SAR). Findings showed that GEO SAR systems provide a valuable contribution for hydrological applications, especially if the possibility to generate many sub-daily observations is sacrificed in favor of higher spatial resolution. In the experiment, it was found that the assimilation of two GEO SAR-like observations a day, with a spatial resolution of 100 m, maximized the performances of the hydrological predictions, for both streamflow and SM state forecasts. Such improvements of the model performances were found to be 45% higher than the ones obtained by assimilating POLAR SAR-like SM maps.

scholarly journals Mathematical Models with Buckling and Contact Phenomena for Elastic Plates: A Review

Mathematics ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 566
Author(s):  
Aliki D. Muradova ◽  
Georgios E. Stavroulakis
Keyword(s):  
Mathematical Models ◽  
Initial Conditions ◽  
Nonlinear Partial Differential Equations ◽  
Composite Plates ◽  
Contact Problems ◽  
Elastic Plates ◽  
Advantages And Disadvantages ◽  
Contact Models ◽  
Set Up ◽  
Unilateral Contact Problems

A review of mathematical models for elastic plates with buckling and contact phenomena is provided. The state of the art in this domain is presented. Buckling effects are discussed on an example of a system of nonlinear partial differential equations, describing large deflections of the plate. Unilateral contact problems with buckling, including models for plates, resting on elastic foundations, and contact models for delaminated composite plates, are formulated. Dynamic nonlinear equations for elastic plates, which possess buckling and contact effects are also presented. Most commonly used boundary and initial conditions are set up. The advantages and disadvantages of analytical, semi-analytical, and numerical techniques for the buckling and contact problems are discussed. The corresponding references are given.

Assessments of Upper Limb Ability following Stroke: A Review

2008 ◽  
Vol 71 (10) ◽  
pp. 427-437 ◽  
Author(s):  
Tennille J Rowland ◽  
Louise Gustafsson
Keyword(s):  
Clinical Practice ◽  
Psychometric Properties ◽  
Upper Limb ◽  
Clinical Utility ◽  
Reliability And Validity ◽  
Psychometric Testing ◽  
Inclusion Criteria ◽  
Test Items ◽  
Advantages And Disadvantages ◽  
Set Up

The aim of this paper was to review the psychometric properties and clinical utility of assessments of upper limb ability following stroke. Upper limb ability was defined as the use of the arm in meaningful activity. The database searches identified 13 assessments of upper limb ability. The inclusion criteria were (a) an evaluation of upper limb ability post-stroke, (b) a quantitative assessment yielding a numerical score, (c) able to be administered by an occupational therapist and (d) published information building on the results of a review in 2001. The assessments included were reviewed with respect to the ability measured, equipment required, evidence of reliability and validity, and advantages and disadvantages of use. Seven assessments satisfied the inclusion criteria. These assessments have undergone varying degrees of psychometric testing as outcome measures for upper limb recovery and all demonstrate at least adequate levels of reliability and validity. There is variation in the availability of instruction manuals and time commitments for test administration. All test items are generally available and inexpensive, enabling departments to set up the assessments with minimal financial outlay. The assessments described are regularly used in research and all demonstrate psychometric properties that suggest that they could be incorporated into clinical practice. Occupational therapists are encouraged to consider how they may include these assessments into their own clinical practice. An important step in this process may be further research into the clinical utility of these assessments.

Gas Turbine Part Load Performance Testing: Comparison of Test Methodologies

2008 ◽  
Author(s):  
Thomas P. Schmitt ◽  
Herve Clement
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Guide Vane ◽  
Performance Testing ◽  
Load Level ◽  
Combined Cycle ◽  
Inlet Guide Vane ◽  
Performance Guarantee ◽  
Part Load ◽  
Advantages And Disadvantages

Current trends in usage patterns of gas turbines in combined cycle applications indicate a substantial proportion of part load operation. Commensurate with the change in operating profile, there has been an increase in the propensity for part load performance guarantees. When a project is structured such that gas turbines are procured as equipment-only from the manufacturer, there is occasionally a gas turbine part load performance guarantee that coincides with the net plant combined cycle part load performance guarantee. There are several methods by which to accomplish part load gas turbine performance testing. One of the more common methods is to operate the gas turbine at the specified load value and construct correction curves at constant load. Another common method is to operate the gas turbine at a specified load percentage and construct correction curves at constant percent load. A third method is to operate the gas turbine at a selected load level that corresponds to a predetermined compressor inlet guide vane (IGV) angle. The IGV angle for this third method is the IGV angle that is needed to achieve the guaranteed load at the guaranteed boundary conditions. The third method requires correction curves constructed at constant IGV, just like base load correction curves. Each method of test and correction embodies a particular set of advantages and disadvantages. The results of an exploration into the advantages and disadvantages of the various performance testing and correction methods for part load performance testing of gas turbines are presented. Particular attention is given to estimates of the relative uncertainty for each method.

Modeling Analysis and Experimental Study of Circular Piezoelectric Unimorph Actuator

2014 ◽  
Vol 599-601 ◽  
pp. 992-996
Author(s):  
Guo Jun Liu ◽  
Xue Lu Yang ◽  
Xu Hao Yang ◽  
Tian Zhao ◽  
Zhi Gang Yang ◽  
...  
Keyword(s):  
Finite Element ◽  
Performance Testing ◽  
Element Model ◽  
Edge Condition ◽  
Coupling Condition ◽  
Pzt Actuator ◽  
Modeling Analysis ◽  
Impedance Testing ◽  
Set Up ◽  
Piezoelectric Unimorph

The finite element model of a circular piezoelectric (PZT) unimorph actuator is set up, the static and dynamic characteristic of the circular PZT actuator are analyzed. For the investigated PZT actuator, comprehensive performance testing is carried out. Compared the simulation results of finite element method with experimental data, the central deflections of PZT actuator under the DC condition are same basically, the testing results show that the actual edge condition lies between clamped and pinned support. The impedance testing results of PZT actuators agree well with FEM analyses. Under AC condition, the central displacement which involves part of resonant component increases greatly by several times more than that under DC condition. While the displacement of actuator with resistance decreases greatly, and is slightly lower than that under DC condition. The relevant research methods lay foundation for the further study of PZT actuator under multi-field coupling condition. Key words: PZT actuator; Circular PZT unimorph; FEM; Static; Dynamic

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