scholarly journals A NEW FULLY-AUTOMATIC PROCEDURE FOR THE IDENTIFICATION AND THE COUPLING OF THE OVERTOPPING WAVES

2018 ◽  
pp. 36 ◽  
Author(s):  
Sara Mizar Formentin ◽  
Barbara Zanuttigh
Keyword(s):  
Flow Velocity ◽  
Water Surface ◽  
Automatic Identification ◽  
Practical Relevance ◽  
Threshold Values ◽  
Flow Conditions ◽  
Fully Automatic ◽  
The Individual ◽  
Coupling Algorithm ◽  
Submerged Conditions

This contribution presents a new procedure for the automatic identification of the individual overtopping events. The procedure is based on a zero-down-crossing analysis of the water-surface-elevation signals and, based on two threshold values, can be applied to any structure crest level, i.e. to emerged, zero-freeboard, over-washed and submerged conditions. The results of the procedure are characterized by a level of accuracy comparable to the human-supervised analysis of the wave signals. The procedure includes a second algorithm for the coupling of the overtopping events registered at two consecutive gauges. This coupling algorithm offers a series of original applications of practical relevance, a.o. the possibility to estimate the wave celerities, i.e. the velocities of propagation of the single waves, which could be used as an approximation of the flow velocity in shallow water and broken flow conditions.

scholarly journals Spectroscopic Techniques versus Pitot Tube for the Measurement of Flow Velocity in Narrow Ducts

Sensors ◽  
2020 ◽  
Vol 20 (24) ◽  
pp. 7349
Author(s):  
Francesco D’Amato ◽  
Silvia Viciani ◽  
Alessio Montori ◽  
Marco Barucci ◽  
Carmen Morreale ◽  
...  
Keyword(s):  
Flow Field ◽  
Flow Velocity ◽  
Pitot Tube ◽  
Optical Measurements ◽  
Trace Gas ◽  
Dual Function ◽  
Spectroscopic Techniques ◽  
Gas Composition ◽  
Flow Conditions ◽  
Theoretical Simulation

In order to assess the limits and applicability of Pitot tubes for the measurement of flow velocity in narrow ducts, e.g., biomass burning plants, an optical, dual function device was implemented. This sensor, based on spectroscopic techniques, targets a trace gas, injected inside the stack either in bursts, or continuously, so performing transit time or dilution measurements. A comparison of the two optical techniques with respect to Pitot readings was carried out in different flow conditions (speed, temperature, gas composition). The results of the two optical measurements are in agreement with each other and fit quite well the theoretical simulation of the flow field, while the results of the Pitot measurements show a remarkable dependence on position and inclination of the Pitot tube with respect to the duct axis. The implications for the metrology of small combustors’ emissions are outlined.

scholarly journals The geometric parameters of plants on the spur dykes in a selected section of the Odra River

2018 ◽  
Vol 45 ◽  
pp. 00110
Author(s):  
Magda Hudak
Keyword(s):  
Water Surface ◽  
Flow Resistance ◽  
Water Levels ◽  
Flow Conditions ◽  
Plant Structure ◽  
Central Section ◽  
Quantitative Characteristics ◽  
Odra River ◽  
The Impact ◽  
Resistance Coefficients

Spur dykes are structures for regulating rivers. They are designed for medium water levels, when spur dyke tops are above the water surface. In the central section of the Odra River the water level is changeable, and the spur dykes work in different hydrological conditions: as non-submerged and submerged. Correct recognition of the plant structure growing on the spur dykes is of great importance in the context of the subsequent allocation of its measure related to the hydraulic action, among others coefficients of resistance of plant zones and refers mainly to grasses. In hydraulic calculations, it is required to determine the value of flow resistance coefficients. In such a departure, the flow is omitted in the area occupied by vegetation. Therefore, it is necessary to know the quantitative characteristics of overgrowth. Vegetation should be presented in the form of a model reflecting the impact of plants growing on the spur dykes and their impact on the water flow conditions in the river. Literature data are not very numerous and are still awake unsatisfied. The paper presents the results of research on the density of vegetation on the Odra River in the Nowa Sól region.

scholarly journals Limitations in the Assessment of Prosthesis-Patient Mismatch

2019 ◽  
Vol 68 (07) ◽  
pp. 550-556 ◽  
Author(s):  
Paulo A. Amorim ◽  
Mahmoud Diab ◽  
Mario Walther ◽  
Gloria Färber ◽  
Andreas Hagendorff ◽  
...  
Keyword(s):  
Flow Velocity ◽  
Surface Area ◽  
Body Surface Area ◽  
Body Surface ◽  
Patient Specific ◽  
Effective Orifice Area ◽  
Pressure Gradients ◽  
Specific Parameter ◽  
Impact On Survival ◽  
The Individual

Abstract Background Prosthesis-patient mismatch (PPM) after aortic valve replacement (AVR) may affect survival but data are conflicting. It is assessed by relating effective orifice area (EOA) to body surface area (EOAi). EOA is patient-specific as the result of flow-velocity times area at the individual patient's outflow tract levels (LVOTA) divided by trans-prosthetic flow velocity. However, some studies use projected EOAs (i.e., valve size associated EOAs from other patient populations) to assess how PPM affects outcome. Methods We analyzed 76 studies addressing hemodynamic outcome and/or mortality after bioprosthetic AVR. Results In 48 studies, projected or measured EOA for calculation of EOAi and PPM assessment was used (of which 25 demonstrated an effect on survival). We identified 28 additional studies providing measured EOA values and the corresponding Bernoulli's pressure gradients after AVR. Despite EOA being a patient-specific parameter, 77% of studies assessing a PPM impact on survival used projected EOAs. The 28 studies are providing measured EOA values and the corresponding Bernoulli's pressure gradients in patients after AVR showed a highly significant, linear relationship between EOA and Bernoulli's gradient. Considering this relationship, it is surprising that relating EOA to body surface area (BSA) (EOAi) is standard but relating pressure gradients to BSA is not. Conclusion We conclude that the majority of studies assessing PPM have used false assumptions because EOA is a patient-specific parameter and cannot be transferred to other patients. In addition, the use of EOAi to assess PPM may not be appropriate and could explain the inconsistent relation between PPM and survival in previous studies.

Effect of spark discharge energy scheduling on ignition under quiescent and flow conditions

2020 ◽  
Vol 234 (12) ◽  
pp. 2878-2891
Author(s):  
Zhenyi Yang ◽  
Xiao Yu ◽  
Hua Zhu ◽  
David S-K Ting ◽  
Ming Zheng
Keyword(s):  
Flow Velocity ◽  
High Power ◽  
Cross Flow ◽  
Spark Discharge ◽  
Discharge Process ◽  
Discharge Energy ◽  
Flow Conditions ◽  
Flame Kernel ◽  
Spark Plug ◽  
Spark Energy

The enhancement of the breakdown power during the spark discharge process has been proved to be beneficial for the flame kernel formation process under lean/diluted conditions. Such a strategy is realized by using a conventional transistor coil ignition system with an add-on capacitance in parallel to the spark plug gap in this paper. In practical application, the use of different ceramic material other than aluminum oxide can change the parasitic capacitance of the spark plug, achieving similar effect in terms of rescheduling the discharge energy released during the breakdown phase. Detailed research has been carried out to investigate the effect of the parallel capacitance and the cross flow velocity on the flame kernel formation and propagation process. With the increase in parallel capacitance, more spark energy is delivered during the breakdown phase, while less energy is released during the arc/glow phase. Shadowgraph images of the spark plasma reveal that the high-power spark discharge can generate a larger high-temperature area with enhanced electrically prompted turbulence under quiescent conditions, as compared with that using the conventional transistor coil ignition discharge strategy under the same condition. The breakdown enhanced turbulence of the high-power spark is proved to be beneficial for the flame kernel development, especially with the lean or exhaust gas recirculation diluted combustible mixtures, given that sufficient spark energy is available for the high-power spark strategy to successfully generate the breakdown event. The results of combustion tests under flow conditions reveal that the breakdown enhanced turbulence of the high-power spark tends to be overshadowed by the turbulence generated from the flow field, and both the increase in flow velocity and parallel capacitance contribute to the reduction in discharge duration of the arc/glow phase. Therefore, the benefits brought about by the high-power spark discharge tend to diminish with the intensification of flow velocity.

Fully automatic identification of AC and PC landmarks on brain MRI using scene analysis

1997 ◽  
Vol 16 (5) ◽  
pp. 610-616 ◽  
Author(s):  
L. Verard ◽  
P. Allain ◽  
J.M. Travere ◽  
J.C. Baron ◽  
D. Bloyet
Keyword(s):  
Brain Mri ◽  
Scene Analysis ◽  
Automatic Identification ◽  
Fully Automatic

scholarly journals Completeness and Accuracy of a Wide-Area Maritime Situational Picture based on Automatic Ship Reporting Systems

2015 ◽  
Vol 69 (1) ◽  
pp. 156-168 ◽  
Author(s):  
Harm Greidanus ◽  
Marlene Alvarez ◽  
Torkild Eriksen ◽  
Vincenzo Gammieri
Keyword(s):  
Data Sources ◽  
Automatic Identification ◽  
Identification System ◽  
Individual Data ◽  
Area Of Interest ◽  
Reporting Systems ◽  
Ship Tracks ◽  
The Individual ◽  
Additional Value ◽  
System Today

Automatic ship reporting systems (AIS – Automatic identification System, LRIT – Long Range Identification and Tracking, VMS – Vessel Monitoring System) today allow global tracking of ships. One way to display the results is in a map of current ship positions over an area of interest, the Maritime Situational Picture (MSP). The MSP is dynamic and must be created by fusing the reporting systems' messages, constructing ship tracks and predicting ship positions to correct for latency especially in the case of AIS received by satellite which forms the bulk of the data. This paper discusses the completeness of the resulting MSP and the accuracy of its positions, quantifying the additional value of the individual data sources.

Meiofauna constitute a considerable portion of invertebrate drift among moss-rich patches within a karst hydrosystem

Biologia ◽  
2014 ◽  
Vol 69 (3) ◽  
Author(s):  
Mirela Perić ◽  
Tvrtko Dražina ◽  
Maria Špoljar ◽  
Ines Radanović ◽  
Biserka Primc ◽  
...  
Keyword(s):  
Flow Velocity ◽  
Spatial Scale ◽  
Early Summer ◽  
Small Scale ◽  
Invertebrate Drift ◽  
Flow Conditions ◽  
Small Spatial Scale ◽  
Minor Influence ◽  
Drift Density ◽  
A Minor

AbstractAiming to establish the most frequent invertebrate taxa in drift at the small spatial scale within a moss-rich karst tufa-precipitating hydrosystem, we sampled drift among microhabitats differing in substratum type and flow conditions along a tufa barrier-cascading lotic reach. Additionally, we addressed the question of the contribution and the potential significance of meiofauna within the overall invertebrate drift at the small spatial scale. During the study period, a total of 60 invertebrate taxa were recorded in the drift. Six of these taxa belonged to the annelid/arthropod meiofauna and they represented 35% of total drift density. Macroinvertebrates found in drift were represented mainly by larval insects. The composition of the most abundant taxa in total drift was as follows: Alona spp. (Cladocera 26.7%), Riolus spp. (Coleoptera: Elmidae 13.2%), Simulium spp. (Diptera: Simuliidae 12.2%), Enchytraeidae (Oligochaeta 10.4%), Hydrachnidia (6.3%), Orthocladinae (Diptera: Chironomidae 3.9%) and Naididae (Oligochaeta 3.6%). Faunal drift densities and amounts of transported particulate matter (PM) were highest at the fast-flowing sites located at the barriers and lowest at the slow-flowing sites within pools. Similarly to the seasonal amounts of transported PM, faunal drift was lowest in winter, and peaked in autumn and in late spring/early summer. Correlation between flow velocity and PM-faunal drift densities suggested a significant effect of the dislodged PM, though a minor influence of discharge and flow velocity on faunal drift. We suggest that the small-scale habitat heterogeneity and the respective feeding and refugial strategies of the fauna, as well as faunal passive dislodgement initiated by the shear forces of the flow were the most important drivers of observed drift patterns.

Research on Traffic Flow Velocity Characteristic at Temporary Reversible Lane

2014 ◽  
Vol 505-506 ◽  
pp. 1189-1193
Author(s):  
Yi Cao ◽  
Zhong Yi Zuo ◽  
Hui Zhi Xu
Keyword(s):  
Flow Velocity ◽  
Traffic Flow ◽  
Existing Problems ◽  
Before And After ◽  
Relationship Model ◽  
Velocity Characteristic ◽  
Utilization Ratio ◽  
The Individual ◽  
Lane Utilization ◽  
The Relationship

In order to analyze the existing problems of temporary reversible lane, traffic flow velocity characteristic at the period of direction changing was analyzed. Taking Huangpu road as the investigation object, the traffic flow velocity parameters before and after direction changing were investigated respectively. By the method of mathematical statistics, the individual vehicles velocities and the traffic flow velocity before and after direction changing were compared and analyzed. Using the method of regression analysis, the relationship model between velocity and density of reversible lane was constructed. This paper also discussed the problems of this kind of lane. The research showed that, in terms of traffic flow operation velocity of temporary reversible lane, there is obvious and regular difference between before and after direction changing. There is a certain relationship between the velocity and density. The problem of lower lane utilization ratio of temporary reversible lane usually exists.

Common feline problem behaviors: Aggression in multi-cat households

2019 ◽  
Vol 21 (3) ◽  
pp. 221-233 ◽  
Author(s):  
Daniela Ramos
Keyword(s):  
Problem Behaviors ◽  
Behavioral Interventions ◽  
Evidence Base ◽  
Practical Relevance ◽  
Care Needs ◽  
Clinical Behavior ◽  
The People ◽  
Large Numbers ◽  
The Individual ◽  
And Behavior

Practical relevance: Being able to understand and intervene in cases of cat–cat aggression in multi-cat households is important for all veterinarians and behavior counsellors dealing with feline behavior cases. Clincal challenges: Feline conflicts are common, perhaps not helped by many owners’ assumption that this is the norm. Interventions can be complex in multi-cat households with large numbers of cats as there are more interactions to evaluate and monitor, and care needs to be taken not to negatively affect the other cats. There may be limitations due to the environment or the people involved and so behavior guidelines should always be tailored to the individual situation. Aims: This article reviews the main forms of aggression in multi-cat households and the appropriate behavioral interventions, considering both the typical scenarios and emotions/motivations most likely involved. It details essential environmental management for multi-cat homes, as well as an approach to friendly cat introductions. Audience: This article is aimed at veterinarians dealing with feline behavior cases as well as behavior counsellors, as both professionals are likely to experience cases of aggression in multi-cat households. Evidence base: The author draws on the published literature where available and, where there is a lack of research, on hypotheses derived from her own clinical behavior experience.

Modeling of the Effect of Washing Solution Flow Conditions on Escherichia coli O157:H7 Population Reduction on Fruit Surfaces

2007 ◽  
Vol 70 (11) ◽  
pp. 2533-2540 ◽  
Author(s):  
HUA WANG ◽  
WEI LIANG ◽  
HAO FENG ◽  
YAGUANG LUO
Keyword(s):  
Escherichia Coli ◽  
Flow Velocity ◽  
Reduction Rate ◽  
Escherichia Coli O157 ◽  
Agitation Rate ◽  
Flow Conditions ◽  
Solution Flow ◽  
E Coli ◽  
Pathogen Reduction ◽  
Over The Top

Washing produce with sanitizing solutions is an important step in reducing microbial populations during postharvest handling. Little information exists regarding the effects of washing solution flow conditions on the efficacy of pathogen reduction during washing. This study was undertaken to investigate the effects of washing conditions such as flow velocity, agitation rate, and contact time on the reduction of Escherichia coli O157:H7 populations from the surfaces of cantaloupe rind and cut apples. Top surfaces of cylindrical samples were spot inoculated with E. coli O157:H7 and treated with peroxyacetic acid (POAA; 80 mg/liter) solution under different flow velocities and agitation rates and with different washing modes. Test results indicate that the reduction rate of E. coli O157:H7 increased with the increase in flow velocity and agitation rate under the testing conditions. In a 3-min treatment in the flow-through chamber, the E. coli O157:H7 count reduction on cantaloupe rind and cup apples reached 2.5 and 2.3 log CFU/cm2, respectively, when the flow velocity increased from 0.0 to 0.8 m/min. Agitation conducted at the bottom of the treatment chamber reduced the E. coli O157:H7 population on cut apples by 1.2 log CFU/cm2 in 3 min, whereas in the treatment with the agitation over the top of the chamber, the survival count of E. coli O157:H7 was reduced by only 0.8 log CFU/cm2. The experimental data were used to fit four microbial reduction kinetic models. It was found that E. coli O157:H7 reduction from the fruit surfaces was best described by the Weibull model. These findings may be useful in designing produce wash systems for achieving enhanced pathogen reduction and improved produce quality and safety.

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