Measurement of sand creep on a flat sand bed using a high-speed digital camera: Mesoscopic features of creeping grains

Sedimentology ◽  
2015 ◽  
Vol 63 (3) ◽  
pp. 629-644 ◽  
Author(s):  
Yang Zhang ◽  
Yuan Wang ◽  
Bin Yang ◽  
Pan Jia
Keyword(s):  
High Speed ◽  
Digital Camera ◽  
Sand Creep ◽  
Flat Sand

Measurement of sand creep on a flat sand bed using a high-speed digital camera

Sedimentology ◽  
2009 ◽  
Vol 56 (6) ◽  
pp. 1705-1712 ◽  
Author(s):  
YUAN WANG ◽  
DAWEI WANG ◽  
LI WANG ◽  
YANG ZHANG
Keyword(s):  
High Speed ◽  
Digital Camera ◽  
Sand Creep ◽  
Flat Sand

Flume investigation of cylindrical baffles for dissipation of debris flow energy

2021 ◽  
Author(s):  
Chan-Young Yune ◽  
Beom-Jun Kim
Keyword(s):  
Energy Dissipation ◽  
Debris Flow ◽  
Debris Flows ◽  
High Speed ◽  
Flow Characteristics ◽  
Digital Camera ◽  
Major Effect ◽  
Small Scale ◽  
Design Guideline ◽  
Flow Energy

<p>A debris flow with a high speed along valleys has been reported to cause serious damages to urban area or infrastructure. To prevent debris flow disaster, countermeasures for flow-impeding structures are installed on the flow path of debris flows. Recently, an installation of cylindrical baffles which are open-type countermeasures has increased because of a low construction cost, filtering out rocks, and an increased hydraulic continuity. However, a comprehensive design guideline for specification and arrangement on cylindrical baffles has not yet been suggested. Moreover, the design of baffle installation is mainly based on empirical approaches as the influence of baffle array on debris mobility is not well understood. In this study, to investigate the effect of cylindrical baffles on the flow characteristics of debris flow, a series of small-scale flume tests were performed according to the varying baffle height and row numbers of installed baffles. High-speed cameras and digital camera to record the flow interaction with baffles were installed at the top and side of the channel. To reproduce the viscosity of debris flows caused by fine-grained soil in the flume, glycerin was mixed with debris materials (sand and gravel). After the test, the velocity and energy dissipation according to various baffle arrays were estimated. Test results showed that the installation of baffles reduced the frontal velocity of debris flows. Furthermore, taller baffles also increased the effect of the energy dissipation in debris flows, but additional rows of the baffle did not have a major effect on the energy dissipation. Thus, increasing the height of baffle led to an increased efficiency of energy dissipation of debris flows.</p>

scholarly journals Influence of Drilling Technique on the Radiographic, Thermographic, and Geomorphometric Effects of Dental Implant Drills and Osteotomy Site Preparations

2020 ◽  
Vol 9 (11) ◽  
pp. 3631
Author(s):  
Lara Fraguas de San José ◽  
Filippo Maria Ruggeri ◽  
Roberta Rucco ◽  
Álvaro Zubizarreta-Macho ◽  
Jorge Alonso Pérez-Barquero ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Dental Implant ◽  
High Speed ◽  
Digital Camera ◽  
Study Groups ◽  
Site Preparation ◽  
Osteotomy Site ◽  
Study Group ◽  
Micro Computed Tomography ◽  
Drilling Technique

The aim of this comparative study is to analyze the influence of drilling technique on the radiographic, thermographic, and geomorphometric effects of dental implant drills and osteotomy site preparations. One hundred and twenty osteotomy site preparations were performed on sixty epoxy resin samples using three unused dental implant drill systems and four drilling techniques performed with a random distribution into the following study groups: Group A: drilling technique performed at 800 rpm with irrigation (n = 30); Group B: drilling technique performed at 45 rpm without irrigation (n = 30); Group C: drilling technique performed at 45 rpm with irrigation (n = 30); and Group D: drilling technique performed at 800 rpm without irrigation (n = 30). The osteotomy site preparation morphologies performed by the 4.1 mm diameter dental implant drills from each study group were analyzed and compared using a cone beam computed tomography (CBCT) scan. The termographic effects generated by the 4.1 mm diameter dental implant drills from each study group were registered using a termographic digital camera and the unused and 4.1 mm diameter dental implant drills that were used 30 times from each study group were exposed to a micro computed tomography (micro-CT) analysis to obtain a Standard Tessellation Language (STL) digital files that determined the wear comparison by geomorphometry. Statistically significant differences were observed between the thermographic and radiographic results of the study groups (p < 0.001). The effect of cooling significatively reduced the heat generation during osteotomy site preparation during high-speed drilling; furthermore, osteotomy site preparation was not affected by the wear of the dental implant drills after 30 uses, regardless of the drilling technique.

Real-time Simultaneous DKG and 2D DKG Using High-speed Digital Camera

2017 ◽  
Vol 31 (2) ◽  
pp. 247.e1-247.e7 ◽  
Author(s):  
Duck-Hoon Kang ◽  
Soo-Geun Wang ◽  
Hee-June Park ◽  
Jin-Choon Lee ◽  
Gye-Rok Jeon ◽  
...  
Keyword(s):  
Real Time ◽  
High Speed ◽  
Digital Camera

scholarly journals Design and Fabrication of a Micropump With Mixing Function for LOC

2008 ◽  
Vol 2 (2) ◽  
Author(s):  
Ho-jin Kang ◽  
Bum-kyoo Choi
Keyword(s):  
Lorentz Force ◽  
High Speed ◽  
Low Voltage ◽  
Flow Direction ◽  
Ionic Current ◽  
Digital Camera ◽  
Working Medium ◽  
Electrode Length ◽  
Portable System ◽  
Phosphate Buffered Saline

A micropump, which includes a mixing function, has been fabricated. For the application to LOC (Lab On a chip), the micropump utilized PBS (Phosphate Buffered Saline) solution as the working medium. The solution is commonly used in biochemistry and cell culturing. The portable system and low energy consumption are important to realize the LOC device. In spite of a low voltage of 4V, the flow rate of the micropump was 0.02466ml∕min. The new micropump shows more enhanced performance than existing micropumps. The micropump uses Lorentz force actuation. The Lorentz force acting onto the ionic current in the PBS solution generates the fluid flow in the micropump. For the accurate prediction on flow direction, a computer simulation has been made using commercial CFD code. The results of simulation showing circulation direction were verified by experiment. The fluid circulation from each electrode combined and acted as the mixer in the micropump. The micropump was fabricated 20.2mm in length, 1mm in width and 400 μm in electrode length. To measure accurately, a high speed digital camera was used.

Effect of Mechanical Vibration on Heat Transfer Characteristics of Liquid Film in Rectangular Microgrooves

2015 ◽  
Author(s):  
Chaohong Guo ◽  
Dong Yu ◽  
Xuegong Hu ◽  
Yuyan Jiang ◽  
Tao Wang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Liquid Film ◽  
Heat Load ◽  
High Speed ◽  
Mechanical Vibration ◽  
Digital Camera ◽  
Vibration Frequencies ◽  
Heat Transfer Characteristics ◽  
Back Wall ◽  
Groove Surface

The effects of vertical mechanical vibration on the heat characteristics of liquid film in vertical rectangular microgrooves are observed. The vibration frequencies are 6Hz, 10Hz and 30Hz, respectively; the vibration amplitudes are in the range of 1.95∼3.23mm. Three sizes of rectangular microgrooved plate are used in experiments. The microgrooved plate is vertically mounted on a vibration plane; DC heat load is added on the back wall of the microgrooved plate. Vibration of the liquid film in the microgroove is observed by a high-speed digital camera, and temperature on the back of the plate is recorded by a data acquisition. The experimental results show that temperature on the plate back decreases obviously with the increase of the vibration frequency or amplitude, heat transfer of the microgrooved plate is intensively enhanced. The main reason is that the forced convections on the groove surface and in the liquid film, caused by the mechanical vibration, enhance the heat transfer. The investigation provides more information for the application of the micro-configuration heat sink under fierce vibration conditions.

Mechanics of Immersed Particle Collisions

1999 ◽  
Vol 121 (1) ◽  
pp. 179-184 ◽  
Author(s):  
Roberto Zenit ◽  
Melany L. Hunt
Keyword(s):  
High Speed ◽  
Control Volume ◽  
Particle Diameter ◽  
Digital Camera ◽  
Pressure Profile ◽  
Stokes Number ◽  
Elastic Collision ◽  
Initial Kinetic Energy ◽  
Fluid Inertia ◽  
Particle Collisions

The present work investigates the mechanics of particle collisions submerged in a liquid using a simple pendulum experiment. Particle trajectories for different particles in water are measured using a high-speed digital camera and the magnitude of the collision is recorded using a high-frequency-response pressure transducer at the colliding surface. The particle deceleration occurs at distances less than half a particle diameter from the wall. The measured collision impulse increases with impact velocity and particle mass. Comparisons are drawn between the measured pressures and the predictions of basic impact mechanics assuming a perfectly elastic collision. A control-volume model is proposed that accounts for the fluid inertia and viscosity. When a particle approaches a planar surface or another particle, the fluid is squeezed prior to contact, reducing the initial kinetic energy and decelerating the particle. The pressure profile is integrated over the surface of the particle to obtain a force that is a function of the initial particle Reynolds number, Reo, and the ratio of the densities of the particle and fluid phases, ρp/ρf. The model predicts a critical Stokes number at which the particle reaches the wall with zero velocity. Comparisons between the proposed model and the experimental measurements show qualitative agreement.

Study of Subcooled Film Boiling on a Horizontal Disc:1 Part 2—Experiments

2000 ◽  
Vol 123 (2) ◽  
pp. 285-293 ◽  
Author(s):  
D. Banerjee ◽  
V. K. Dhir
Keyword(s):  
Liquid Phase ◽  
Particle Tracking ◽  
Bubble Growth ◽  
High Speed ◽  
Particle Tracking Velocimetry ◽  
Digital Camera ◽  
Film Boiling ◽  
Convection Flow ◽  
Vapor Bubbles ◽  
Natural Convection Flow

Experiments were performed to study subcooled film boiling of performance liquid PF-5060 (made by 3-M Company) on a horizontal copper disc. The experiments were performed for two regimes of film boiling involving departing vapor bubbles (low subcooling) and nondeparting vapor bubbles (high subcooling). By employing high speed digital camera, data were obtained for temporal variation of bubble height, bubble shape and bubble growth rate over one cycle. Heat flux data were deduced from temperatures measured with thermocouples embedded in the solid. The results from the numerical model are compared with experimental data and are found to be in general agreement. Particle Tracking Velocimetry (PTV) experiments were performed for a configuration of non-departing vapor bubbles to study the flow field in the liquid phase. The PTV experiments point to the existence of natural convection flow in the liquid phase and is in qualitative agreement with the predictions available in the literature.

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