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Articles 201481 - 201510 of 1114360

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Studying Complex Aquifer Systems From Large-Scale Stratigraphy Development To Local Aquifer Storage And Recovery, Hamid Vahdat Aboueshagh Jul 2021

Studying Complex Aquifer Systems From Large-Scale Stratigraphy Development To Local Aquifer Storage And Recovery, Hamid Vahdat Aboueshagh

LSU Doctoral Dissertations

Hydrostratigraphy model is an essential component of building valid groundwater models. Many challenges are associated with constructing hydrostratigraphy models which include geological complexities such as faults, domes, and angular unconformities. Developing a method with an emphasis on capturing big data to thoroughly inform large-scale models is one of the challenges addressed in the first part of this study. The method is predicated upon discretization of the study domain into tiles based on the geological dip direction and faults. The application of the method in the state of Louisiana with the utilization of more than 114000 well logs demonstrates promising results …

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Testing Functional Variation In Thermal Properties For Antarctic Mosses, Andrew Forrest Clements Jul 2021

Testing Functional Variation In Thermal Properties For Antarctic Mosses, Andrew Forrest Clements

Dissertations and Theses

As the maritime Antarctic ecosystem continues to warm, glacial retreat will further expose subterranean permafrost to warmer conditions. One of the most visible changes in the ecosystem is the colonization of the new ice-free areas by bryophytes, particularly mosses. These bryophytes are having important effects on terrestrial thermal properties, but little is known about differences among Antarctic moss species in their thermal properties. Here, I measured the thermal conductivity, specific heat capacity, and the water content of moss species on King George Island to understand the insulation ability of Antarctic mosses, Polytrichastrum alpinum, Sanionia georgicouncinata, Chorisodontium aciphyllum, …

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Double And Triple Bouncing Spinning Soccer Ball, Shafat A. Mubin Jul 2021

Double And Triple Bouncing Spinning Soccer Ball, Shafat A. Mubin

Georgia Journal of Science

The trajectories of soccer ball penalty kicks that strike one of the goal-posts while rolling along the surface are simulated and analyzed using conservation of linear and angular momenta. The reflected trajectories upon collisions with the goalpost are calculated and used to determine whether double or triple bounces take place. The analysis is iterated for a range of initial launch speeds, angular velocities, and normal and tangential coefficients of restitution of the goalpost-ball collisions. It is observed that double bounces can take place for almost any combination of the above parameters if the soccer ball strikes the appropriate narrow sectors …

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P2v-Rcnn: Point To Voxel Feature Learning For 3d Object Detection From Point Clouds, Jiale Li, Yu Sun, Shujie Luo, Ziqi Zhu, Hang Dai, Andrey S. Krylov, Yong Ding, Ling Shao Jul 2021

P2v-Rcnn: Point To Voxel Feature Learning For 3d Object Detection From Point Clouds, Jiale Li, Yu Sun, Shujie Luo, Ziqi Zhu, Hang Dai, Andrey S. Krylov, Yong Ding, Ling Shao

Computer Vision Faculty Publications

The most recent 3D object detectors for point clouds rely on the coarse voxel-based representation rather than the accurate point-based representation due to a higher box recall in the voxel-based Region Proposal Network (RPN). However, the detection accuracy is severely restricted by the information loss of pose details in the voxels. Different from considering the point cloud as voxel or point representation only, we propose a point-to-voxel feature learning approach to voxelize the point cloud with both the point-wise semantic and local spatial features, which maintains the voxel-wise features to build the high-recall voxel-based RPN and also provides the accurate …

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Keeping Balance Between Genetic Stability And Plasticity At The Telomere And Subtelomere Of Trypanosoma Brucei, Bibo Li Ph.D. Jul 2021

Keeping Balance Between Genetic Stability And Plasticity At The Telomere And Subtelomere Of Trypanosoma Brucei, Bibo Li Ph.D.

Biological, Geological, and Environmental Faculty Publications

Telomeres, the nucleoprotein complexes at chromosome ends, are well-known for their essential roles in genome integrity and chromosome stability. Yet, telomeres and subtelomeres are frequently less stable than chromosome internal regions. Many subtelomeric genes are important for responding to environmental cues, and subtelomeric instability can facilitate organismal adaptation to extracellular changes, which is a common theme in a number of microbial pathogens. In this review, I will focus on the delicate and important balance between stability and plasticity at telomeres and subtelomeres of a kinetoplastid parasite, Trypanosoma brucei, which causes human African trypanosomiasis and undergoes antigenic variation to evade the …

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Cataloging Virtual Reality Artworks: Challenges And Future Prospects, Cory Aitchison Jul 2021

Cataloging Virtual Reality Artworks: Challenges And Future Prospects, Cory Aitchison

Pepperdine University Libraries

In 2019, Pepperdine Libraries acquired two virtual reality artworks by filmmaker and artist Paisley Smith: Homestay and Unceded Territories. To bring awareness to these pieces, Pepperdine Libraries added these works to the library catalog, creating bibliographic records for both films. There were many challenges and considerations in cataloging virtual reality art, including factors such as the nature of the work, the limits found in Resource Description and Access (RDA) and MARC, and providing access to these works. This paper discusses these topics, as well as provides recommendations for potential future standards for cataloging virtual works.

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Experimental And Numerical Analysis Of The Hydraulic Jump Stilling Basin And The Downstream Scour Depth, L. J. Miranda, R. Sánchez Jul 2021

Experimental And Numerical Analysis Of The Hydraulic Jump Stilling Basin And The Downstream Scour Depth, L. J. Miranda, R. Sánchez

International Junior Researcher and Engineer Workshop on Hydraulic Structures

This paper presents a study of a tridimensional low-head hydraulic jump stilling basin by using both physical and numerical models. Laboratory tests up to 15 hours in duration were carried out in a 1.9 m wide and 14 m long flume. Four gates produced a jet with a submerged hydraulic jump in a positive-step stilling basin, after which scour developed in a nearly uniform sand bed. Acoustic Doppler Velocimeter, piezometers and image processing were used to collect the hydrodynamic data, and Reynolds Averaged Navier-Stokes simulations developed in OpenFOAM were tested for validation purposes. Then, the study focused on (1) the …

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Three-Dimensional Characterization Of Laboratory Scour Holes Around Bridge Piers, Ana Margarida Bento, Teresa Viseu, João Pedro Pêgo, Lúcia Couto Jul 2021

Three-Dimensional Characterization Of Laboratory Scour Holes Around Bridge Piers, Ana Margarida Bento, Teresa Viseu, João Pedro Pêgo, Lúcia Couto

International Junior Researcher and Engineer Workshop on Hydraulic Structures

The presence of a bridge foundation leads to the formation of a scour hole, from which entrainment and transport of sediments are controlled by the turbulent structures therein developed. Hence, once formed, these scour holes interfere significantly with the scouring process in several ways, for instance, by modifying the incoming flow patterns. Therefore, a three-dimensional survey of the scour hole and the characterization of the deposition features is essential for prevention and safety control purposes. To investigate this, scouring experiments around two oblong bridge piers were performed in a tilting flume of the Portuguese National Laboratory of Civil Engineering (LNEC), …

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Scour Downstream Of Log-Frame Structures In The Presence Of Rigid Vegetation, Deep Roy, Simone Pagliara Jul 2021

Scour Downstream Of Log-Frame Structures In The Presence Of Rigid Vegetation, Deep Roy, Simone Pagliara

International Junior Researcher and Engineer Workshop on Hydraulic Structures

Recently, various low-head environment friendly structures have been used to control the sediment transport and preserve river navigability. Among these structures, double winged log-frames are effective for concentrating the flow by decreasing channel width. Moreover, they create scour holes which can be used by fishes as resting spots. Usually, log-frames are placed in mountainous curved channels where there is natural growth of various types of in-stream vegetation in the downstream stilling basin of the structure which influences scour geometry and depth. Therefore, the current study aims to analyze the impact of rigid woody vegetation, placed downstream of double winged log-frames, …

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Estimation Of The Efficiency Of Hydraulic Pumps, A. Martin-Candilejo, D. Santillán, L. Garrote Jul 2021

Estimation Of The Efficiency Of Hydraulic Pumps, A. Martin-Candilejo, D. Santillán, L. Garrote

International Junior Researcher and Engineer Workshop on Hydraulic Structures

A sustainable design of water supply systems needs to account operational costs. When pumping is required, the energy consumed by the pumps plays a major part in the operational costs, and the efficiency of the pumps can greatly affect the energy expenses. How to properly estimate the value of pump efficiency is hence of great importance. The aim of this study is to study in depth the efficiency of hydraulic pumps, in relation with the other design variables (flow rate, pumping head, power, etc.). For that, 400 hydraulic pumps were analysed. A strong relationship between the flow rate and the …

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Streamflow Duration Curves: Focus On Low Flows, E. Carcano, M. Betasolo Jul 2021

Streamflow Duration Curves: Focus On Low Flows, E. Carcano, M. Betasolo

International Junior Researcher and Engineer Workshop on Hydraulic Structures

Flow duration curves (FDCs) express the link between a selected streamflow and the percentage in time such value is exceeded. The curves provide a graphical insight into hydrological regimes, though, the absence of time-series data is a significant shortcoming. Conversely to what happens with hygrograms, flows in FDCs are represented without regard of sequence of occurrence. This paper explores FDCs of 19 catchments for which, at least, 10 years of daily discharges are available. FDCs can be built for any temporal scale (i.e. daily, weekly, monthly). In this study daily discharges have been adopted because daily scale better represents the …

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Flow Distribution In Slotted Pipe Bottom Outlets, Felipe Azevedo Paulo, Eder Daniel Teixeira Jul 2021

Flow Distribution In Slotted Pipe Bottom Outlets, Felipe Azevedo Paulo, Eder Daniel Teixeira

International Junior Researcher and Engineer Workshop on Hydraulic Structures

Reservoir sedimentation is a major threat to dam operation. It can reduce water storage capacity, clog water intakes, and damage turbine components. Flushing operations by bottom outlets are a mitigation measure that allows removing sediment deposited near the dam. Unfortunately, the effect of such structures is localized if no water level draw down takes place; therefore, investigations of new designs that improve sediment removal have emerged recently. In this work, we present our current results on the investigation of the slotted pipe bottom outlet obtained through numerical modeling. The flow patterns were characterized for different water levels, showing that discharges …

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In Vivo Printing Of Growth Factor-Eluting Adhesive Scaffolds Improves Wound Healing, Kristo Nuutila, Mohamadmahdi Samandari, Yori Endo, Yuteng Zhang, Jacob Quint, Tannin A. Schmidt, Ali Tamayol, Indranil Sinha Jul 2021

In Vivo Printing Of Growth Factor-Eluting Adhesive Scaffolds Improves Wound Healing, Kristo Nuutila, Mohamadmahdi Samandari, Yori Endo, Yuteng Zhang, Jacob Quint, Tannin A. Schmidt, Ali Tamayol, Indranil Sinha

Department of Mechanical and Materials Engineering: Faculty Publications

Acute and chronic wounds affect millions of people around the world, imposing a growing financial burden on patients and hospitals. Despite the application of current wound management strategies, the physiological healing process is disrupted in many cases, resulting in impaired wound healing. Therefore, more efficient and easy-to-use treatment modalities are needed. In this study, we demonstrate the benefit of in vivo printed, growth factor-eluting adhesive scaffolds for the treatment of full-thickness wounds in a porcine model. A custom-made handheld printer is implemented to finely print gelatin-methacryloyl (GelMA) hydrogel containing vascular endothelial growth factor (VEGF) into the wounds. In vitro and …

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Calibration Of A Hydraulic Model For Seasonal Flooding In A Lowland River With Natural Diversions And Bathymetric Uncertainty, For Dam Downstream Impact Assessment, Getachew E. Mamo, Davide Motta, Martin Crapper Jul 2021

Calibration Of A Hydraulic Model For Seasonal Flooding In A Lowland River With Natural Diversions And Bathymetric Uncertainty, For Dam Downstream Impact Assessment, Getachew E. Mamo, Davide Motta, Martin Crapper

International Junior Researcher and Engineer Workshop on Hydraulic Structures

A method is developed to generate bank-full river main channel geometry, to complement an open-source Digital Elevation Model (DEM) and produce a calibrated hydraulic model reproducing the extent of historically observed overbank flooding. This approach relies on limited surveyed cross section and flow rate information and is potentially suitable for projects in developing countries where the availability of measured data is limited. The method presented is applied to the case of the seasonal flooding of the Baro River in the Gambela floodplain in Ethiopia, modelled with a two-dimensional hydraulic model. The simulated flooding extent for the 1990 wet season is …

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Particle Image Velocimetry (Piv) Investigation Of Local Scour Around Emergent And Submerged Circular Cylinders, P. Williams, R. Balachandar, V. Roussinova, R. Barron Jul 2021

Particle Image Velocimetry (Piv) Investigation Of Local Scour Around Emergent And Submerged Circular Cylinders, P. Williams, R. Balachandar, V. Roussinova, R. Barron

International Junior Researcher and Engineer Workshop on Hydraulic Structures

Analysis of the velocity field surrounding a circular cylinder under equilibrium of local scour has been restricted due to practical limitations of commonly used measurement techniques. This investigation summarizes select cases in the literature which have attempted to circumvent such limitations and presents flow field measurements using Particle Image Velocimetry (PIV). Scour tests were conducted in a horizontal flume fitted with a sediment recess containing erodible bed material. Tests were conducted with both emergent and submerged circular cylinders for a period of 24 hours, after which equilibrium was achieved and planar PIV measurements were obtained in the streamwise-vertical symmetry plane. …

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Comparison Of Pressure Distribution In 2d And 3d Jet-Driven Scour Processes, Simone Pagliara, Deep Roy Jul 2021

Comparison Of Pressure Distribution In 2d And 3d Jet-Driven Scour Processes, Simone Pagliara, Deep Roy

International Junior Researcher and Engineer Workshop on Hydraulic Structures

Water jets impacting on a non-cohesive granular bed cause a dynamic pressure distribution on the surface of the scour hole. Such distribution greatly differs from the hydrostatic one, especially in proximity of the impact zone, where the kinetic energy of the jet is dissipates due to the shear stresses acting on the scour surface. Here, the excess of shear stress causes the erosion of the bed material and can lead to the failure of hydraulic structures. Therefore, a detailed analysis of the forces acting on the scour surface is fundamental to understand the erosion mechanisms. Experimental tests were conducted under …

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Modelling Velocity Profiles Of Aerated Flows Down Grassed Spillways, H. Cui, S. Felder, M. Kramer Jul 2021

Modelling Velocity Profiles Of Aerated Flows Down Grassed Spillways, H. Cui, S. Felder, M. Kramer

International Junior Researcher and Engineer Workshop on Hydraulic Structures

The ecological and environmental benefits of grassed spillways present a green solution to the construction of low head conveyance structures. On a grassed spillway, the aggregate of the grass canopy and root structure may alter flow resistance, velocity distribution and other flow properties. While subcritical flows in vegetated open channels have been extensively researched, only little is known about flow properties in supercritical high-velocity flows, which are typically characterized by self-aeration. The current study explores the application of a velocity superposition to supercritical aerated flows on a spillway with artificial grass. Velocity measurements were conducted with a Pitot tube and …

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Large-Scale Morphodynamic Impact Of Groups Of Piers On Low-Land Rivers, Abdelrahman Abdou, Daniel Valero, Alessandra Crosato Jul 2021

Large-Scale Morphodynamic Impact Of Groups Of Piers On Low-Land Rivers, Abdelrahman Abdou, Daniel Valero, Alessandra Crosato

International Junior Researcher and Engineer Workshop on Hydraulic Structures

This study explores the morphodynamic impact of groups of piers with different configurations (i.e., span characteristics, number of piers, and different reach locations) in a river cross section. It focuses on sandy low-land rivers presenting steady alternate bars and low Froude numbers. A 2DH (vertically integrated) numerical physics-based model (Delft3D) is used to simulate a straight channel, which is inspired from a Nile River reach in Egypt, downstream of the High Aswan Dam. The results show the formation of a forced bar upstream and downstream of the piers and increased deposition over the existing steady bars with different intensities. The …

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A Critical Analysis Of Jet-Induced Scour Formulas, J. Di Nardi, M. Palermo, S. Pagliara Jul 2021

A Critical Analysis Of Jet-Induced Scour Formulas, J. Di Nardi, M. Palermo, S. Pagliara

International Junior Researcher and Engineer Workshop on Hydraulic Structures

Many studies investigate erosive processes occurring in non-cohesive granular materials downstream of grade-control structures, dam spillways, headcuts, and other hydraulic structures. Because of the complexity of the scour mechanism, the analysis of the scour phenomenon caused by plunging jets is generally conducted by using physical models and particularly for specific structure geometries. In this regard, many researchers proposed empirical approaches to estimate the main scour lengths, but their contributions are limited to tested conditions and cannot be generalized. This lack of generality has been (partially) overcome by other, more recent, approaches, that are either semitheoretical or fully theoretical. Previous works …

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Numerical Simulation Of Fish Passage Over A Weir, Linus Kaminski, C. Thorenz, R. Weichert Jul 2021

Numerical Simulation Of Fish Passage Over A Weir, Linus Kaminski, C. Thorenz, R. Weichert

International Junior Researcher and Engineer Workshop on Hydraulic Structures

Downstream migration over weir structures has been a mostly neglected element of ecological continuity in the last decades. The guidelines currently applied in Germany to prevent damage to fish do not sufficiently consider the conditions present at weirs. To improve knowledge of the risks of fish passage over a weir due to physical strike, pressure changes and shear stress, a numerical method using the three-dimensional computational fluid dynamics package OpenFOAM® was developed to simulate fish passage over a weir by tracking passively transported particles. In this study, the method is tested on an overshot and an undershot weir and the …

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Effect Of Boundary-Layer Development On The Water-Surface Fluctuations Of Supercritical Flow Below A Sluice Gate, Ryugen Satoh, M. Takahashi, I. Ohtsu Jul 2021

Effect Of Boundary-Layer Development On The Water-Surface Fluctuations Of Supercritical Flow Below A Sluice Gate, Ryugen Satoh, M. Takahashi, I. Ohtsu

International Junior Researcher and Engineer Workshop on Hydraulic Structures

Hydraulic structures with a sluice gate are commonly used for control of the flow. In supercritical flow below a sluice gate, an accurate estimation of the water depth and boundary layer thickness is important for the hydraulic design of a horizontal apron. The relation between water-surface fluctuations and boundary-layer development has not been clarified. The aim of this paper is to experimentally demonstrate the effect of boundary-layer development on water-surface fluctuations of supercritical flow below a sluice gate. It is shown that water surface begins to fluctuate slightly upstream of the critical point. The water-surface fluctuations and turbulence intensities downstream …

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Cfd Simulation Of Supercritical Flow In Narrow Channels Including Sediment Bypass Tunnels, Subhojit Kadia, Elena Pummer, Nils RüTher Jul 2021

Cfd Simulation Of Supercritical Flow In Narrow Channels Including Sediment Bypass Tunnels, Subhojit Kadia, Elena Pummer, Nils RüTher

International Junior Researcher and Engineer Workshop on Hydraulic Structures

Secondary currents, turbulence characteristics and bed shear stress distribution are the crucial parameters for specifying sediment transport. Hence, to understand the sediment transport in sediment bypass tunnels (SBTs), we performed computational fluid dynamics (CFD) simulation of supercritical flow in a narrow straight channel. The results of the steady state simulation (Froude number ≈ 1.8) were compared with experimental results. The commonly used two-equations linear eddy-viscosity models are limited to isotropic turbulence closure and hence could not replicate the desired secondary currents. Therefore, the LRR Reynolds Stress Model was used, and predicted the flow features and the secondary currents (three kinds …

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Probability Of Woody Debris Passage At Rock Weirs, Kathryn A. Margetts, B. M. Crookston Jul 2021

Probability Of Woody Debris Passage At Rock Weirs, Kathryn A. Margetts, B. M. Crookston

International Junior Researcher and Engineer Workshop on Hydraulic Structures

Often, large woody debris (LWD) at hydraulic structures is considered hazardous from a performance and public safety perspective. However, the sustainable management of rivers requires the consideration of ecological impacts of LWD such as cover for aquatics and the natural movement of LWD through a catchment. Therefore, this study explores the interaction of natural (nonuniform) LWD with rock weirs through field observations in the Blacksmith Fork River in Utah, USA and laboratory testing at the Utah Water Research Laboratory. The passage probability of individual LWD at rock weirs is observed and tested in an effort to describe the balance between …

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Laboratory Experiments On Long Waves Interacting With Rigid Vertical Cylinders, R. Basile, F. De Serio, D. Raffaele Jul 2021

Laboratory Experiments On Long Waves Interacting With Rigid Vertical Cylinders, R. Basile, F. De Serio, D. Raffaele

International Junior Researcher and Engineer Workshop on Hydraulic Structures

The impact of waves caused by storm surges or floods could lead to significant damage to marine and fluvial structures. Hydraulic forces add significant hydrodynamic loads on bridges built in coastal and fluvial environments; therefore, the effect of the wave impact on bridge substructures must be properly considered for the safe and cost-effective design of the piers. The use of laboratory-scale models is a direct approach to investigate the effects of long waves on simple structures, mimicking bridge piers. The present study describes a laboratory-scale model, where the propagation of two different long waves in a flume, in the presence …

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Approach Flow Depth Influence On Nonlinear Weir Discharge Capacity, Benane Redha, Sebastien Erpicum, Michel Pirotton Jul 2021

Approach Flow Depth Influence On Nonlinear Weir Discharge Capacity, Benane Redha, Sebastien Erpicum, Michel Pirotton

International Junior Researcher and Engineer Workshop on Hydraulic Structures

The high hydraulic efficiency and the compactness of nonlinear weirs favor their use in several rehabilitation or new dams projects. Main types of nonlinear weirs are labyrinth and piano key weirs.The purpose of this paper is to provide indications on the influence of the approach flow depth on the discharge capacity of these nonlinear weirs. To do so, a series of experimental tests have been carried out in the laboratory of Engineering Hydraulics of the Liege University. A labyrinth and a piano key weir have been tested in channel configuration (upstream flow width equal to the weir width) considering various …

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Discharge Capacity Of A Piano Key Weir With Curvilinear Keys, R. K. Mishra, Z. Ahmad Jul 2021

Discharge Capacity Of A Piano Key Weir With Curvilinear Keys, R. K. Mishra, Z. Ahmad

International Junior Researcher and Engineer Workshop on Hydraulic Structures

The Piano Key Weir (PKW) has emerged as a cost effective and viable solution for dam rehabilitation and new projects with high level of space constraints. The geometrical dimensions of PKW are main factors affecting their discharging capacity. Since, it is a relatively new type of weir that has only been developed in recent years, the description of the effect of its geometrical parameters is still immature. The geometric designs of these weirs presented in the literatures incorporate only linear floor slope of the keys. For better understanding of the influence of curvilinear shapes of outlet key slopes on discharge …

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Development Of A 1 Kw Gravitational Water Vortex Hydropower Plant Prototype, A. Sapkota, A. Gautam, A. B. Timilsina, S. Dhakal, S. R. Shakya, T. R. Bajracharya Jul 2021

Development Of A 1 Kw Gravitational Water Vortex Hydropower Plant Prototype, A. Sapkota, A. Gautam, A. B. Timilsina, S. Dhakal, S. R. Shakya, T. R. Bajracharya

International Junior Researcher and Engineer Workshop on Hydraulic Structures

A pilot testing of a Gravitational Water Vortex Hydropower Plant (GWVHP) has been done to evaluate the applicability in a real-world scenario and validate the results from the lab-scale model. A scaled-up model of a capacity of 1 kW was constructed for the evaluation purpose. The test provided data in good agreement with a lab-scale model and a proper visualization to install Gravitational Water Vortex in real-world scenarios. The project lasted for nearly four months and thus provided important information on the problems that might arise in scaling up the lab model to a micro-hydro system. The pilot testing shows …

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Development Of Grass-Roots Data Collection Methods In Rural, Isolated, And Tribal Communities, Kevin Chang, Cody Hodgson Jul 2021

Development Of Grass-Roots Data Collection Methods In Rural, Isolated, And Tribal Communities, Kevin Chang, Cody Hodgson

CSET Project Reports

While extensive procedures have been developed for the collection and dissemination of motor vehicle volumes and speeds, these same procedures cannot always be used to collect pedestrian data, given the comparably unpredictable behavior of pedestrians and their smaller physical size. There is significant value to developing lower cost, lower intrusion methods of collecting pedestrian travel data, and these collection efforts are needed at the local or “grass-roots” level. While previous studies have documented many different data collection methods, one newer option considers the use of drones. This study examined its feasibility to collect pedestrian data and used this technology as …

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Fingerprinting The Cretaceous-Paleogene Boundary Impact With Zn Isotopes, Ryan Mathur, Brandon Mahan, Marissa Spencer, Linda Godfrey, Neil Landman, Matthew Garb, D. Graham Pearson, Sheng-Ao Liu, Francisca E. Oboh-Ikuenobe Jul 2021

Fingerprinting The Cretaceous-Paleogene Boundary Impact With Zn Isotopes, Ryan Mathur, Brandon Mahan, Marissa Spencer, Linda Godfrey, Neil Landman, Matthew Garb, D. Graham Pearson, Sheng-Ao Liu, Francisca E. Oboh-Ikuenobe

Publications and Research

Numerous geochemical anomalies exist at the K-Pg boundary that indicate the addition of extraterrestrial materials; however, none fingerprint volatilization, a key process that occurs during large bolide impacts. Stable Zn isotopes are an exceptional indicator of volatilityrelated processes, where partial vaporization of Zn leaves the residuum enriched in its heavy isotopes. Here, we present Zn isotope data for sedimentary rock layers of the K-Pg boundary, which display heavier Zn isotope compositions and lower Zn concentrations relative to surrounding sedimentary rocks, the carbonate platform at the impact site, and most carbonaceous chondrites. Neither volcanic events nor secondary alteration during weathering and …

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Effects Of Hole Inclination On The Film Cooling Techniques., Samir Hanna, Mahmoud Awad, Nabil Matta Jul 2021

Effects Of Hole Inclination On The Film Cooling Techniques., Samir Hanna, Mahmoud Awad, Nabil Matta

Mansoura Engineering Journal

This paper presents an experimental investigation on the injection characteristics of a single hole at the leading edge of a flat plate immersed in mainstream air. The influence of the hole diameter, hole inclination angle , and pressure difference coefficients on the flow rate coefficient of an injection hole is investigated. For designing film cooled blades, it is necessary to predict the characterestics of the coolant flow rate from each injection hole. It is found that the maximum flow rate coefficient occurs at a hole inclination angle of 35o for different hole diameter and different pressure coefficient. Flow rate coefficient …

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