scholarly journals Impact of bed surface arrangement on bedload rate: comparisons between loose, armored and water-worked beds

2018 ◽  
Vol 40 ◽  
pp. 05036
Author(s):  
Emeline Perret ◽  
Céline Berni ◽  
Benoît Camenen
Keyword(s):  
Large Scale ◽  
Laboratory Data ◽  
Laser Scanner ◽  
Packed Bed ◽  
Mountain Rivers ◽  
Water Power ◽  
Bed Forms ◽  
Hydraulic Conditions ◽  
Original Laboratory ◽  
Initial Arrangement

Existing formulas for predicting bedload rate may be not adapted for mountain rivers with poorly sorted sediments, partly because they were often established using laboratory data with conditions far from those found in such rivers. Natural bed arrangement is particularly difficult to reproduce in flumes, although recent studies highlighted its importance on bedload dynamics. This study aims to quantify bed arrangement impact on bedload rate using original laboratory tests and to improve existing bedload formulas. Three types of bed composed with the same material but having different bed arrangements were studied: loose beds were installed manually in the flume and the others, packed and water-worked beds, were created using water power. Packed beds were assimilated to flat beds composed of a static armor layer whereas water-worked beds exhibited stronger bed organization, including large-scale bed forms. Laser-scanner surveys were used to characterize differences in bed morphology. Similar unsteady hydraulic conditions were applied over these beds. Results showed that bedload dynamics varies significantly depending on the initial arrangement. Compared to loose bed, bedload was enhanced over water-worked bed and reduced over packed bed. Bed surface indicators are thus important parameters to take into account when predicting gravel transport.

scholarly journals Dynamic Loads and Response of a Spar Buoy Wind Turbine with Pitch-Controlled Rotating Blades: An Experimental Study

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3598
Author(s):  
Sara Russo ◽  
Pasquale Contestabile ◽  
Andrea Bardazzi ◽  
Elisa Leone ◽  
Gregorio Iglesias ◽  
...  
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Degrees Of Freedom ◽  
Large Scale ◽  
Laboratory Data ◽  
Nonlinear Behavior ◽  
Offshore Wind ◽  
Small Scale ◽  
Wave Steepness ◽  
Design Factor

New large-scale laboratory data are presented on a physical model of a spar buoy wind turbine with angular motion of control surfaces implemented (pitch control). The peculiarity of this type of rotating blade represents an essential aspect when studying floating offshore wind structures. Experiments were designed specifically to compare different operational environmental conditions in terms of wave steepness and wind speed. Results discussed here were derived from an analysis of only a part of the whole dataset. Consistent with recent small-scale experiments, data clearly show that the waves contributed to most of the model motions and mooring loads. A significant nonlinear behavior for sway, roll and yaw has been detected, whereas an increase in the wave period makes the wind speed less influential for surge, heave and pitch. In general, as the steepness increases, the oscillations decrease. However, higher wind speed does not mean greater platform motions. Data also indicate a significant role of the blade rotation in the turbine thrust, nacelle dynamic forces and power in six degrees of freedom. Certain pairs of wind speed-wave steepness are particularly unfavorable, since the first harmonic of the rotor (coupled to the first wave harmonic) causes the thrust force to be larger than that in more energetic sea states. The experiments suggest that the inclusion of pitch-controlled, variable-speed blades in physical (and numerical) tests on such types of structures is crucial, highlighting the importance of pitch motion as an important design factor.

A Punched-Card System for the Laboratory

1962 ◽  
Vol 8 (5) ◽  
pp. 538-545 ◽  
Author(s):  
Nathan Radin
Keyword(s):  
Clinical Chemistry ◽  
Laboratory Data ◽  
Chemistry Laboratory ◽  
Test Card ◽  
Clinical Chemistry Laboratory ◽  
Original Laboratory ◽  
Numerical Order ◽  
Card System ◽  
A Charge ◽  
Laboratory Record

Abstract A punched-card system was developed to simplify the administrative aspects of the clinical chemistry laboratory. In it a three-part requisition and samples are matched and given a laboratory number. The third copy of the original laboratory requsition is a charge card also used as a name file for the day. Prepunched cards, coded for laboratory tests, are used for each test requested. The laboratory number is stamped and punched on each test card. All test cards are then sorted into laboratory test groups, after which the laboratory data and results are recorded on them. Cards are then sorted for laboratory number and rematched with the original laboratory requisitions, which remained in numerical order. Results are then copied directly onto the requisitions. The system is more efficient, less susceptible to error, and simpler than other laboratory record systems.

scholarly journals Factors Enhancing Serum Syndecan-1 Concentrations: A Large-Scale Comprehensive Medical Examination

2019 ◽  
Vol 8 (9) ◽  
pp. 1320
Author(s):  
Kazumasa Oda ◽  
Hideshi Okada ◽  
Akio Suzuki ◽  
Hiroyuki Tomita ◽  
Ryo Kobayashi ◽  
...  
Keyword(s):  
Large Scale ◽  
Prospective Observational Study ◽  
Nitrogen Concentration ◽  
Laboratory Data ◽  
University Hospital ◽  
Endothelial Glycocalyx ◽  
Sample Collection ◽  
Blood Samples ◽  
Triglyceride Concentration ◽  
Medical Examinations

Endothelial disorders are related to various diseases. An initial endothelial injury is characterized by endothelial glycocalyx injury. We aimed to evaluate endothelial glycocalyx injury by measuring serum syndecan-1 concentrations in patients during comprehensive medical examinations. A single-center, prospective, observational study was conducted at Asahi University Hospital. The participants enrolled in this study were 1313 patients who underwent comprehensive medical examinations at Asahi University Hospital from January 2018 to June 2018. One patient undergoing hemodialysis was excluded from the study. At enrollment, blood samples were obtained, and study personnel collected demographic and clinical data. No treatments or exposures were conducted except for standard medical examinations and blood sample collection. Laboratory data were obtained by the collection of blood samples at the time of study enrolment. According to nonlinear regression, the concentrations of serum syndecan-1 were significantly related to age (p = 0.016), aspartic aminotransferase concentration (AST, p = 0.020), blood urea nitrogen concentration (BUN, p = 0.013), triglyceride concentration (p < 0.001), and hematocrit (p = 0.006). These relationships were independent associations. Endothelial glycocalyx injury, which is reflected by serum syndecan-1 concentrations, is related to age, hematocrit, AST concentration, BUN concentration, and triglyceride concentration.

scholarly journals Chemical looping reforming in packed-bed reactors: Modelling, experimental validation and large-scale reactor design

2017 ◽  
Vol 156 ◽  
pp. 156-170 ◽  
Author(s):  
V. Spallina ◽  
B. Marinello ◽  
F. Gallucci ◽  
M.C. Romano ◽  
M. Van Sint Annaland
Keyword(s):  
Large Scale ◽  
Experimental Validation ◽  
Packed Bed ◽  
Reactor Design ◽  
Chemical Looping ◽  
Packed Bed Reactors ◽  
Scale Reactor

Seeding metrics for image velocimetry performances in rivers

2021 ◽  
Author(s):  
Silvano Fortunato Dal Sasso ◽  
Alonso Pizarro ◽  
Sophie Pearce ◽  
Ian Maddock ◽  
Matthew T. Perks ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Optical Sensors ◽  
Large Scale ◽  
Surface Flow ◽  
Surface Velocity ◽  
Seeding Density ◽  
Earth System ◽  
Science Data ◽  
Image Velocimetry ◽  
Hydraulic Conditions

&lt;p&gt;Optical sensors coupled with image velocimetry techniques are becoming popular for river monitoring applications. In this context, new opportunities and challenges are growing for the research community aimed to: i) define standardized practices and methodologies; and ii) overcome some recognized uncertainty at the field scale. At this regard, the accuracy of image velocimetry techniques strongly depends on the occurrence and distribution of visible features on the water surface in consecutive frames. In a natural environment, the amount, spatial distribution and visibility of natural features on river surface are continuously challenging because of environmental factors and hydraulic conditions. The dimensionless seeding distribution index (SDI), recently introduced by Pizarro et al., 2020a,b and Dal Sasso et al., 2020, represents a metric based on seeding density and spatial distribution of tracers for identifying the best frame window (FW) during video footage. In this work, a methodology based on the SDI index was applied to different study cases with the Large Scale Particle Image Velocimetry (LSPIV) technique. Videos adopted are taken from the repository recently created by the COST Action Harmonious, which includes 13 case study across Europe and beyond for image velocimetry applications (Perks et al., 2020). The optimal frame window selection is based on two criteria: i) the maximization of the number of frames and ii) the minimization of SDI index. This methodology allowed an error reduction between 20 and 39% respect to the entire video configuration. This novel idea appears suitable for performing image velocimetry in natural settings where environmental and hydraulic conditions are extremely challenging and particularly useful for real-time observations from fixed river-gauged stations where an extended number of frames are usually recorded and analyzed.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;&lt;strong&gt;References &lt;/strong&gt;&lt;/p&gt;&lt;p&gt;Dal Sasso S.F., Pizarro A., Manfreda S.,&amp;#160;Metrics for the Quantification of Seeding Characteristics to Enhance Image Velocimetry Performance in Rivers.&amp;#160;Remote Sensing,&amp;#160;12, 1789 (doi: 10.3390/rs12111789), 2020.&lt;/p&gt;&lt;p&gt;Perks M. T., Dal Sasso S. F., Hauet A., Jamieson E., Le Coz J., Pearce S., &amp;#8230;Manfreda S, Towards harmonisation of image velocimetry techniques for river surface velocity observations. Earth System Science Data, https://doi.org/10.5194/essd-12-1545-2020, 12(3), 1545 &amp;#8211; 1559, 2020.&lt;/p&gt;&lt;p&gt;Pizarro A., Dal Sasso S.F., Manfreda S.,&amp;#160;Refining image-velocimetry performances for streamflow monitoring: Seeding metrics to errors minimisation,&amp;#160;Hydrological Processes, (doi: 10.1002/hyp.13919), 1-9, 2020.&lt;/p&gt;&lt;p&gt;Pizarro A., Dal Sasso S.F., Perks M. and Manfreda S., Identifying the optimal spatial distribution of tracers for optical sensing of stream surface flow, Hydrology and Earth System Sciences, 24, 5173&amp;#8211;5185, (10.5194/hess-24-5173-2020), 2020.&lt;/p&gt;

scholarly journals An adsorption theory of heterogeneous nucleation of water vapour on nanoparticles

2015 ◽  
Vol 15 (15) ◽  
pp. 21883-21906
Author(s):  
A. Laaksonen ◽  
J. Malila
Keyword(s):  
Water Vapour ◽  
Heterogeneous Nucleation ◽  
Large Scale ◽  
Laboratory Data ◽  
Theoretical Description ◽  
Nucleation Theory ◽  
Cloud Formation ◽  
Scale Model ◽  
Adsorption Theory ◽  
Ice Cloud

Abstract. Heterogeneous nucleation of water vapour on insoluble nuclei is a phenomenon that can induce atmospheric water and ice cloud formation. However, modelling of the phenomenon is hampered by the fact that the predictive capability of the classical heterogeneous nucleation theory is rather poor. A reliable theoretical description of the influence of different types of water-insoluble nuclei in triggering the water condensation or ice deposition would help to decrease uncertainty in large scale model simulations. In this paper we extend a recently formulated adsorption theory of heterogeneous nucleation to be applicable to highly curved surfaces, and test the theory against laboratory data for water vapour nucleation on silica, titanium dioxide and silver oxide nanoparticles. We show that unlike the classical heterogeneous nucleation theory, the new theory is able to quantitatively predict the experimental results.

scholarly journals Causes and consequences of long-term groundwater overabstraction in Jordan

2021 ◽  
Author(s):  
Florian Brückner ◽  
Rebecca Bahls ◽  
Mohammad Alqadi ◽  
Falk Lindenmaier ◽  
Ibraheem Hamdan ◽  
...  
Keyword(s):  
Water Supply ◽  
Large Scale ◽  
Flow Direction ◽  
Groundwater Resources ◽  
Regional Scale ◽  
Irrigated Agriculture ◽  
Groundwater Levels ◽  
Contour Lines ◽  
Hydraulic Conditions ◽  
Groundwater Basins

AbstractIn 2017, a comprehensive review of groundwater resources in Jordan was carried out for the first time since 1995. The change in groundwater levels between 1995 and 2017 was found to be dramatic: large declines have been recorded all over the country, reaching more than 100 m in some areas. The most affected areas are those with large-scale groundwater-irrigated agriculture, but areas that are only used for public water supply are also affected. The decrease of groundwater levels and saturated thickness poses a growing threat for drinking water supply and the demand has to be met from increasingly deeper and more remote sources, causing higher costs for drilling and extraction. Groundwater-level contour lines show that groundwater flow direction has completely reversed in some parts of the main aquifer. Consequently, previously established conceptual models, such as the concept of 12 “groundwater basins” often used in Jordan should be revised or replaced. Additionally, hydraulic conditions are changing from confined to unconfined; this is most likely a major driver for geogenic pollution with heavy metals through leakage from the overlying bituminous aquitard. Three exemplary case studies are presented to illustrate and discuss the main causes for the decline of the water tables (agriculture and population growth) and to show how the results of this assessment can be used on a regional scale.

scholarly journals UAV and terrestrial laser scanner data processing for large scale topographic mapping

2020 ◽  
Vol 50 ◽  
pp. 63-73
Author(s):  
Ganbold Ulziisaikhan ◽  
Dash Oyuntsetseg
Keyword(s):  
Data Processing ◽  
Spatial Data ◽  
Large Scale ◽  
Laser Scanner ◽  
Measurement Technology ◽  
Topographic Mapping ◽  
Terrestrial Laser Scanner ◽  
Scanner Data ◽  
Processing Scheme ◽  
Digital Elevation

Integrating spatial data from different sources results in visualization, which is the last step in the process of digital basic topographic map creation. Digital elevation model and visualization will used for geomorphological mapping, geospatial database, urban planning and etc. Large scale topographic mapping in the world countries is really a prominent challenge in geospatial industries today. The purpose of this work is to integrate laser scanner data with the ones generated by aerial photogrammetry from UAV, to produce detailed maps that can used by geodetic engineers to optimize their analysis. In addition, terrestrial - based LiDAR scans and UAV photogrammetric data were collected in Sharga hill in the north zone of Mongolia. In this paper, different measurement technology and processing software systems combined for topographic mapping in the data processing scheme. UTM (Universal Transverse Mercator) projected coordinate system calculated in WGS84 reference ellipsoid. Feature compilation involving terrestrial laser scanner data and UAV data will integrated to offer Digital Elevation Models (DEM) as the main interest of the topographic mapping activity. Used UAV generate high-resolution orthomosaics and detailed 3D models of areas where no data, are available. That result issued to create topographic maps with a scale of 1:1000 of geodetic measurements. Preliminary results indicate that discontinuity data collection from UAV closely matches the data collected using laser scanner.

scholarly journals Apron and Cutoff Wall Scour Protection for Piano Key Weirs

Water ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2332
Author(s):  
Wyatt Lantz ◽  
Brian Mark Crookston ◽  
Michele Palermo
Keyword(s):  
Large Scale ◽  
Open Channel ◽  
Control Structure ◽  
Cutoff Wall ◽  
Specific Design ◽  
Experimental Campaign ◽  
Hydraulic Conditions ◽  
Weir Height ◽  
Scour Protection ◽  
Design Guidance

Piano key (PK) weirs are used in a variety of flow control structure applications, including spillway crests and open channel diversion structures. However, to the best of authors’ knowledge, structure-specific design guidance for scour mitigation is still needed. To fill this gap of knowledge, a systematic experimental campaign was conducted by testing different configurations of horizontal aprons with a cutoff wall. Protection structures were located at the toe of the PK weir. Namely, experiments were performed at large-scale to assess the effect of three apron lengths on downstream scour hole geometry under different hydraulic conditions. It was observed that a horizontal apron deflects the plunging jets originating from the PK weir, thus significantly reducing scour. Experimental evidence allowed corroboration that significant scour depth reduction occurs for an apron length 1.5 times the weir height, with longer aprons found to provide marginal benefits. Finally, also provided herein are tools to estimate the main scour characteristics and help practitioners in optimizing apron design.

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