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High-speed Camera (high-speed + camera)
Selected AbstractsA Large-scale Mutagenesis Screen to Identify Seizure-resistant ZebrafishEPILEPSIA, Issue 6 2007Scott C. Baraban Summary:,Methods: Seizures were induced with pentylenetetrazole (PTZ). Zebrafish were analyzed between 3 and 7 days postfertilization (dpf). Genome mutations were induced in founders by using N- ethyl-nitrosourea (ENU). Seizure behavior was monitored by using a high-speed camera and quantified by locomotion-tracking software. Electrographic activity was monitored by using a field-recording electrode placed in the optic tectum of agar-immobilized zebrafish. Results: Short-term PTZ exposure elicited a burst-suppression seizure pattern in 3-dpf zebrafish and more complex activity consisting of interictal- and ictal-like discharges at 7 dpf. Prolonged exposure to PTZ induced status epilepticus,like seizure activity and fatality in wild-type zebrafish larvae. With a PTZ survival assay at 6,7 dpf, we identified six zebrafish mutants in a forward-genetic screen covering nearly 2,000 F2 families. One mutant (s334) also was shown to exhibit reduced behavioral activity on short-term PTZ exposure and an inability to generate long-duration ictal-like discharge. Conclusions: Zebrafish offers a powerful tool for the identification and study of a genetic basis for seizure resistance. [source] Influence of track surface on the equine superficial digital flexor tendon loading in two horses at high speed trotEQUINE VETERINARY JOURNAL, Issue 3 2009N. Crevier-Denoix Summary Reasons for performing study: Although track surfaces are a risk factor of tendon injuries, their effects on tendon loading at high speed are unknown. Using a noninvasive ultrasonic technique, it is now possible to evaluate the forces in the superficial digital flexor tendon (SDFT) in exercise conditions. Objectives: To compare the effects of an all-weather waxed track (W) vs. a crushed sand track (S), on the SDFT loading in the trotter horse at high speed. Methods: Two trotter horses were equipped with the ultrasonic device (1 MHz ultrasonic probe, fixed on the palmar metacarpal area of the right forelimb). For each trial, data acquisition was made at 400 Hz and 10 consecutive strides were analysed. In each session, the 2 track surfaces were tested in a straight line. The speed was imposed at 10 m/s and recorded. The right forelimb was also equipped with a dynamometric horseshoe and skin markers. The horse was filmed with a high-speed camera (600 Hz); all recordings were synchronised. Statistical differences were tested using the GLM procedure (SAS; P<0.05). Results: Maximal tendon force was significantly lower on W compared with S. In addition to maximal force peaks around mid-stance, earlier peaks were observed, more pronounced on S than on W, at about 13%(horse 2) and 30% (both horses) of the stance phase. Comparison with kinematic data revealed that these early peaks were accompanied by plateaux in the fetlock angle-time chart. For high tendon forces, the tendon maximal loading rate was significantly lower on W than on S. Conclusions and potential clinical relevance: The all-weather waxed track appears to induce a lesser and more gradual SDFT loading than crushed sand. The SDFT loading pattern at high speed trot suggests proximal interphalangeal joint movements during limb loading. [source] 3D computer simulation of melt flow and heat transfer in the lost foam casting processINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 5 2003S. M. H. Mirbagheri Abstract A new mathematical model has been developed to simulate mould filling in the lost foam casting process, using the finite difference method. The simulation of molten flow and track of free surfaces is based on the SOLA-VOF numerical technique. An algorithm was developed to calculate the gas pressure of the evaporated foam during the mould filling. The effect of backpressure on the filling behaviour was modelled with an experimental function by adding three-dimensions 3DVOF functions. In order to verify the computational results, a thin grey iron plate was poured into a transparent mould. Cavity filling, foam depolymerization and gap formation were recorded with a 16mm high-speed camera. A good agreement was achieved for simulation results of filling sequences with those from experiments. Copyright © 2003 John Wiley & Sons, Ltd. [source] RTSVC: Real-time system for visual control of robotsINTERNATIONAL JOURNAL OF IMAGING SYSTEMS AND TECHNOLOGY, Issue 4 2008Eusebio Bugarin Abstract This article presents an image processing system that can work in hard real-time. Compared with systems that use the traditional multiprocessor architecture approach, this computer system takes advantage on recent technological advances and it is designed to work with a single processor PC under RTLinux. Its programming environment is similar to C programming language and it offers a friendly graphical user interface. The performance of the system is illustrated by means of experiments applied to visual guidance of mobile robots via velocity fields using a fixed high-speed camera. The experiments were carried out with a strict sampling frequency of 100 Hz. © 2008 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 18, 251,256, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). [source] Study on factors influencing stagnation point offset of turbulent opposed jetsAICHE JOURNAL, Issue 10 2010Wei-Feng Li Abstract Turbulent opposed jets were experimentally studied by the hot-wire anemometer measurement, the smoke-wire flow visualization, and the CFD simulation at L = 1,20D (where L is the nozzle separation and D is the nozzle diameter) and Re > 4500. The instability pattern of turbulent opposed jets was identified by investigating the smoke-wire photos recorded by a high-speed camera. The factors affecting stagnation point offset, such as the bulk velocity, the velocity profile, and the turbulence intensity at the nozzle exits were investigated. Results show that the stagnation point offset is the main instability regime of turbulent opposed jets. Uniform exit velocity profile and increasing exit turbulence intensity will decrease the stagnation point offset of turbulent opposed jets. © 2010 American Institute of Chemical Engineers AIChE J, 2010 [source] Dynamic Compressive Failure of AlON Under Controlled Planar ConfinementJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 11 2008Bhasker Paliwal An experimental technique is developed to impose a planar lateral confinement in a prismatic specimen (with a rectangular cross section); the setup enabled a controlled and homogeneous stress state with high lateral compressive stresses. A transparent polycrystalline aluminum oxynitride (AlON) specimen was used for the study. The statically precompressed specimen was then subjected to axial dynamic compressive loading using a modified compression Kolsky bar setup. Experimental design was performed using 3D computational modeling. Initial exploratory experiments were conducted on AlON at an average planar confinement of 400,410 MPa; the results suggested a higher compressive strength and a nonlinear stress evolution in AlON due to the confinement. A high-speed camera was used to observe the damage evolution in the specimen during the course of loading. The photographs and stress evolution are suggestive of an additional inelastic deformation mechanism, whose evolution is slower than the typical brittle-cracking type of damage apparent in the unconfined case. The TEM and high-resolution electron microscope analysis indicated dislocation plasticity in some fragments; dislocations in the slip bands were characterized to be dissociated ,110, dislocations on {111} planes. The width between two partial dislocations was about 15 nm, suggesting low stacking fault energy of AlON. Microscopic characterization also shows that the eventual fragmentation of AlON is by cleavage mainly along low-index {111} planes. [source] Effects of operating conditions on particle size in sonocrystallizationASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 4 2010Hussein Oubani Abstract This work presents systematic investigations on sonocrystallization to elucidate the effects of key variables on sonocrystallization product properties. A novel continuous flow sonocrystallization apparatus was used to prepare NaCl microparticles from a NaCl,ethanol,water antisolvent system. By implementing a full factorial experimental design, we investigated the effects of ultrasonic power (75,225 W), antisolvent feed rate (0.5,6.5 l/h), system flow rate (2.8,4.1 l/min) and sonication time (5,30 min) on product crystal size. Data from these experiments were regressed to develop an empirical model that was found to be in agreement with experiments. The model identified the interaction between sonication power and system flow to be rather significant. Model simulations found that particle size decreases when antisolvent feed rate or ultrasonic power increases. This was found to be in contrast to increasing the system flow which resulted in larger particle sizes. The regression model was subsequently used to determine optimal operating conditions that minimize mean size, as smaller sizes are commonly required for pharmaceuticals such as for inhalation particles. These optimal values were found to be as follows: antisolvent flow rate = 6.5 l/h, power ultrasound = 225 W, system flow = 2.8 l/min and sampling time = 15 min. The optimal mean size predicted at these conditions was 28.6 ± 5.7 µm which is very close to the observed value of 27.6 µm. A high-speed camera was used to visualize the ultrasonic irradiation in the sonoreactor and was crucial in explaining the significant interactive effect of sonication power and system flow on crystal size. Copyright © 2010 Curtin University of Technology and John Wiley & Sons, Ltd. [source] Study of liquid droplets impact on dry inclined surfaceASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 5 2009Jie Cui Abstract The impact of droplets on the surface is a common phenomenon. The outcome of a droplet impacting on a solid surface depends on the properties of the liquid, the surface conditions and the kinematics parameters, i.e. velocity and momentum. During the impact process, the phenomenons, such as spread, rebound, often appear. This paper presents the results of an experimental investigation of droplets impacting on inclined solid surface at low velocity. The effects of the impact parameters on the droplet impingement are studied. Measures were performed using a high-speed camera. It has been shown that the impacting droplets spread on the surface until liquid surface tension and viscosity overcame inertial forces, after which they recoiled off the surface. The maximum diameter of a droplet spread was measured. In addition, a further forecasting expression has been obtained through energy model when a droplet impacts on an inclined surface without splashing. It is found that it is in good agreement with experimental value and can well predict the maximum spread diameter. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source] | |||||||||||||