Effect of Liquid Properties on Thermal Mixing in a T-Junction

2014 ◽  
Author(s):  
O. N. Kashinsky ◽  
P. D. Lobanov ◽  
A. S. Kurdyumov ◽  
N. A. Pribaturin
Keyword(s):  
Temperature Field ◽  
High Speed ◽  
Three Dimensional ◽  
Infrared Image ◽  
Infrared Camera ◽  
Dimensional Structure ◽  
Thin Wall ◽  
Channel Diameter ◽  
Different Temperatures ◽  
Different Diameters

Results of experimental study of mixing of liquids with different temperatures in a T-junction are presented. Experiments were performed with liquids which have significantly different physical properties. The liquid with higher temperature was injected through the branch of the T-junction. The test section was made of thin wall stainless tubes. The distribution of wall temperature over the surface was measured using a high speed infrared camera. Both time averaged and fluctuational characteristics of the temperature field were obtained from infrared image processing. The structure of temperature field inside the channel was measured by a microthermocouple. It was mounted on the traversing unit which allowed its translation along the channel diameter. Measurements were made over different diameters in the same cross section. This allowed to construct the three-dimensional structure of the temperature field. Results obtained provide experimental data necessary for validation of thermo hydraulic codes for the design of power equipment.

Thermal Mixing of Liquid Metal Coolant in an Annular Channel

2016 ◽  
Author(s):  
O. N. Kashinsky ◽  
P. D. Lobanov ◽  
N. A. Pribaturin ◽  
A. S. Kurdyumov ◽  
M. A. Vorobyev
Keyword(s):  
High Speed ◽  
Liquid Metals ◽  
Experimental Studies ◽  
Infrared Camera ◽  
Annular Channel ◽  
Thin Wall ◽  
Thermal Mixing ◽  
Transient Regimes ◽  
Different Temperatures ◽  
Metal Coolant

Results of experimental studies of mixing of liquids with different temperatures are presented. Experiments were performed in a T-junction connected to an annular channel. Rose’s metal was used as the test liquid. The test section was made of thin wall stainless tubes. The distribution of wall temperatures was measured using a high speed infrared camera. Experiments were performed in transient regimes. Results obtained provide experimental data necessary for validation of thermal hydraulic codes for heavy liquid metals.

Incipient Flow Boiling in a Vertical Channel With a Wavy Wall

2010 ◽  
Author(s):  
T. Netz ◽  
R. Shalem ◽  
J. Aharon ◽  
G. Ziskind ◽  
R. Letan
Keyword(s):  
Heat Transfer ◽  
Temperature Field ◽  
High Speed ◽  
Flow Boiling ◽  
Heated Surface ◽  
Vertical Channel ◽  
Infrared Camera ◽  
Heat Fluxes ◽  
Heated Wall ◽  
Boiling Incipience

In the present study, incipient flow boiling of water is studied experimentally in a square-cross-section vertical channel. Water, preheated to 60–80 degrees Celsius, flows upwards. The channel has an electrically heated wall, where the heat fluxes can be as high as above one megawatt per square meter. The experiment is repeated for different water flow rates, and the maximum Reynolds number reached in the present study is 27,300. Boiling is observed and recorded using a high-speed digital video camera. The temperature field on the heated surface is measured with an infrared camera and a software is used to obtain quantitative temperature data. Thus, the recorded boiling images are analyzed in conjunction with the detailed temperature field. The dependence of incipient boiling on the flow and heat transfer parameters is established. For a flat wall, the results for various velocities and subcooling conditions agree well with the existing literature. Furthermore, three different wavy heated surfaces are explored, having the same pitch of 4mm but different amplitudes of 0.25mm, 0.5mm and 0.75mm. The effect of surface waviness on single-phase heat transfer and boiling incipience is shown. The differences in boiling incipience on various surfaces are elucidated, and the effect of wave amplitude on the results is discussed.

scholarly journals High-Speed Volumetric Observation of a Wet Microburst Using X-Band Phased Array Weather Radar in Japan

2016 ◽  
Vol 144 (10) ◽  
pp. 3749-3765 ◽  
Author(s):  
Toru Adachi ◽  
Kenichi Kusunoki ◽  
Satoru Yoshida ◽  
Ken-ichiro Arai ◽  
Tomoo Ushio
Keyword(s):  
High Speed ◽  
Phased Array ◽  
Three Dimensional ◽  
Weather Radar ◽  
Ground Level ◽  
Dimensional Structure ◽  
Convection Cell ◽  
Low Level ◽  
X Band ◽  
Traffic Operation

This paper reports a high-speed volumetric observation of a wet microburst event using X-band phased array weather radar (PAWR) in Japan. On 10 September 2014, PAWR observed the three-dimensional structure of a convection cell, which had a vertical extent of 5–6 km and a horizontal dimension of 2–10 km, moving toward the east-northeast. At 2310 Japan standard time (JST), a precipitation core with a radar reflectivity of >40 dBZ appeared at 3–5 km above ground level. The core then increased in size and intensity and rapidly descended to the ground. During this time, a reflectivity notch associated with midlevel inflow was initially formed near the top of the precipitation core and, subsequently, at lower altitudes. A strong low-level outflow with a radial divergence of >4 × 10−3 s−1 appeared just below the notch at around 2321 JST. The outflow lasted for approximately 13 min and eventually disappeared after 2333 JST along with dissipation of the causative storm cell. These results suggest that, in addition to hydrometeor loading, evaporative cooling due to the entrainment of midlevel relatively dry air played an additional role in driving a strong downdraft. The preceding signatures including descending precipitation core, reflectivity notch, and midlevel convergence observed by PAWR are useful precursors to forecast the occurrence of low-level wind shear 5–10 min ahead, which is important for safe air traffic operation.

The Comparison of Four Pressure-Thermal Models of Oil Film Bearing With the Non-Newtonian and Temperature-Viscosity Effects

2016 ◽  
Author(s):  
Feng Liang ◽  
Quanyong Xu ◽  
Xudong Lan ◽  
Ming Zhou
Keyword(s):  
Temperature Field ◽  
Numerical Model ◽  
High Speed ◽  
Reynolds Equation ◽  
Pressure Field ◽  
Journal Bearing ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Oil Film ◽  
Viscosity Effects

The thermohydrodynamic analysis of oil film bearing is essential for high speed oil film bearing. The temperature field is coupled with the pressure field. The numerical model can be built or chosen according to the complexity of the objects and requirement of the accuracy. In this paper, four pressure-thermal (P-T) models are proposed, which are zero-dimensional temperature field coupled with Reynolds equation (0D P-T model), two-dimensional temperature field coupled with Reynolds equation (2D P-T model), two-dimensional temperature with third dimensional correction coupled with Dawson equation (2sD P-T model), three-dimensional temperature field coupled with Dawson equation (3D P-T model). The non-Newtonian and temperature-viscosity effects of the lubrication oil are considered in all the four models. Two types of cylindrical journal bearing, the bearing with/without axial grooves, are applied for the simulation. All the simulated cases are compared with the solutions of the CFX. The results show that the 0D P-T model fails to predict the behavior of high speed bearing; The 2D and 2sD P-T model have an acceptable accuracy to predict the performance of the bearing without grooves, but are not able to simulate the P-T field of the bearing with grooves because of the under-developed thermal boundary layer; The 2sD P-T model shows a great improvement when calculating the pressure field compared with the 2D P-T model; the 3D P-T model coincides well with the CFX at any condition. The comparison of these four models provides a reference to help designer choose a proper numerical model for a certain project.

Orthogonal Variable Thickness Cutting Modeling of Surface Milling and Physical Fields Simulation

2016 ◽  
Vol 836-837 ◽  
pp. 468-475
Author(s):  
Wei Zhang ◽  
Chang Jian Du ◽  
Xiao Liang Cheng ◽  
Feng Shun He
Keyword(s):  
Temperature Field ◽  
Variable Thickness ◽  
High Speed ◽  
End Milling ◽  
Three Dimensional ◽  
Complex Surface ◽  
Work Piece ◽  
Ball End Milling ◽  
Physical Fields ◽  
Cutting Model

When milling the complex surface with the ball-end milling cutter, the cutting thickness always changes in ball-end milling process. At present, many milling models are actually simplified with unchanged cutting thickness, which ignores the ball-end milling cutting with complex tool-work piece relationship. According to the characteristics of the ball-end milling, orthogonal variable thickness cutting model is established based on the study of three-dimensional contact relationship of tool-work piece. The simulation of the stress field and the temperature field in hardened steel Cr12MoV orthogonal variable thickness cutting process is conducted, and comparative analysis of stress and temperature field distribution of high-speed milling and conventional milling is made. The cutting model of orthogonal variable thickness cutting can reflect the characteristics of surface milling accurately, which can be further used in the study of changing characteristics of physical fields and the optimization of cutting and tool parameters to improve the machining efficiency and quality.

scholarly journals In situstructures of periplasmic flagella inBorreliareveals conformational changes essential for flagellar rotation

2019 ◽  
Author(s):  
Yunjie Chang ◽  
Kihwan Moon ◽  
Xiaowei Zhao ◽  
J. Norris Steven ◽  
Md A. Motaleb ◽  
...  
Keyword(s):  
Conformational Change ◽  
Conformational Changes ◽  
High Speed ◽  
Electron Tomography ◽  
Proton Translocation ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Flagellar Motor ◽  
Flagellar Filament ◽  
Flagellar Rotation

SUMMARYThe bacterial flagellar motor is a molecular machine that rotates the flagellar filament at high speed. Torque is generated by the stator-rotor interaction coupled to an ion flux through the torque-generating stator. Here, we employed cryo-electron tomography to visualize the intact flagellar motor in the Lyme disease spirocheteBorrelia burgdorferi. By analysis of the motor structures of wild-type and stator mutants, we localize the torque-generating units precisely and determine three-dimensional structure of the stator and its interactions with the rotor. Our study shows that the cytoplasmic domains of the stator are packed regularly around the circumference of the flagellar C-ring. The stator-rotor interaction induces a profound conformational change in the C-ring. Analysis of the motors of a less motilemotB-D24E mutant and a non-motilemotB-D24N mutant, in which the proton translocation is reduced and blocked, respectively, provides evidence that the conformational change of the C-ring is essential for flagellar rotation.

Inverse Conduction Heat Transfer and Kriging Interpolation Applied to Temperature Sensor Location in Microchips

2018 ◽  
Vol 140 (1) ◽  
Author(s):  
David Gonzalez Cuadrado ◽  
Amy Marconnet ◽  
Guillermo Paniagua
Keyword(s):  
Heat Transfer ◽  
Temperature Field ◽  
Hot Spot ◽  
Three Dimensional ◽  
Infrared Image ◽  
Temperature Sensors ◽  
Kriging Interpolation ◽  
Algorithm Optimization ◽  
Element Analysis ◽  
Specification Method

Large thermal gradients represent major operational hazards in microprocessors; hence, there is a critical need to monitor possible hot spots both accurately and in real time. Thermal monitoring in microprocessors is typically performed using temperature sensors embedded in the electronic board. The location of the temperature sensors is primarily determined by the sensor space claim rather than the ideal location for thermal management. This paper presents an optimization methodology to determine the most beneficial locations for the temperature sensors inside of the microprocessors, based on input from high-resolution surface infrared thermography combined with inverse heat transfer solvers to predict hot spot locations. Specifically, the infrared image is used to obtain the temperature map over the processor surface, and subsequently delivers the input to a three-dimensional (3D) inverse heat conduction methodology, used to determine the temperature field within the processor. In this paper, simulated thermal maps are utilized to assess the accuracy of this method. The inverse methodology is based on a function specification method combined with a sequential regularization in order to increase accuracy in the results. Together with the number of sensors, the temperature field within the processor is then used to determine the optimal location of the temperature sensors using a genetic algorithm optimization combined with a Kriging interpolation. This combination of methodologies was validated against the finite element analysis of a chip incorporating heaters and temperature sensors. An uncertainty analysis of the inverse methodology and the Kriging interpolation was performed separately to assess the reliability of the procedure.

Sizes of Particles, Clumps, and Gaps Within the Strong Janus 2:1 and Mimas 5:3 Density Waves from Cassini UVIS Stellar Occultation Data Statistics

2020 ◽  
Author(s):  
Stephanie Eckert ◽  
Joshua Colwell ◽  
Richard Jerousek ◽  
Larry Esposito
Keyword(s):  
High Speed ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Density Waves ◽  
Sight Distance ◽  
Wide Range ◽  
Stellar Occultations ◽  
Occultation Data ◽  
Self Gravity ◽  
Ring Material

<p>The high-speed photometer of Cassini’s Ultraviolet Imaging Spectrograph (UVIS) collected data from stellar occultations across Saturn’s rings at unprecedented high resolution over a wide range of viewing geometries. Because photon counts are described by Poisson statistics, we expect a variance equal to the mean in the absence of intervening ring material. However, most ring ‘particles’ are truly aggregates of smaller particles, ranging from micron-size dust to tens of meter-sized boulders, and if the sizes of these aggregates are not small relative to the field-of-view over a single integration period, they introduce excess variance from which we can glean further information about the sizes of particles and clumps. This is particularly relevant in the A ring, where non-axisymmetric self-gravity wakes are ubiquitous. Larger elongated clumps nicknamed straw have been directly imaged in the troughs of strong density waves (Porco et al., 2005, Science, 307, 1226-1236). In this work we present a survey of the statistical moments of variance and skewness for several ring stellar occultations at two strong density waves from different ring regions, Janus 2:1 and Mimas 5:3, over a variety of viewing angles. The line-of-sight distance from Cassini to the rings affects the measurement area due to the scattered signal and diffraction, and different viewing angles provide measurements of the same ring material with different aspects to potentially reveal the three-dimensional structure of clumps. We calculate an effective particle size per integration area, R, derived by Colwell et al., (2018, Icarus, 300, 150-166) and find similar values for R in both peaks and troughs across density waves as well as within density waves and in adjacent regions. We observe strong statistical similarity between troughs and regions adjoining the waves with overall higher skewness in the A ring, indicating more clumping and greater asymmetry in this region than in the inner B ring region.</p>

BSSB:BLASTServer for Structural Biologists

2011 ◽  
Vol 44 (3) ◽  
pp. 651-654 ◽  
Author(s):  
Muthukumarasamy Uthayakumar ◽  
Govindhan Sowmiya ◽  
Radhakrishnan Sabarinathan ◽  
N. Udayaprakash ◽  
M. Kirti Vaishnavi ◽  
...  
Keyword(s):  
High Speed ◽  
Three Dimensional ◽  
Pairwise Alignment ◽  
Query Protein ◽  
Dimensional Structure ◽  
Local Alignment ◽  
Three Dimensional Structure ◽  
Level Information ◽  
Search Tool ◽  
The Subject

The Basic Local Alignment Search Tool (BLAST) is one of the most widely used sequence alignment programs with which similarity searches, for both protein and nucleic acid sequences, can be performed against large databases at high speed. A large number of tools exist for processingBLASToutput, but none of them provide three-dimensional structure visualization. This shortcoming has been addressed in the proposed toolBLASTServer for Structural Biologists (BSSB), which maps aBLASToutput onto the three-dimensional structure of the subject protein. The three-dimensional structure of the subject protein is represented using a three-color coding scheme (identical: red; similar: yellow; and mismatch: white) based on the pairwise alignment obtained. Thus, the user will be able to visualize a possible three-dimensional structure for the query protein sequence. This information can be used to gain a deeper insight into the sequence–structure correlation. Furthermore, the additional structure-level information enables the user to make coherent and logical decisions regarding the type of input model structure or fragment that can be used for molecular replacement calculations. This tool is freely available to all users at http://bioserver1.physics.iisc.ernet.in/bssb/.

scholarly journals A connectomic study of a petascale fragment of human cerebral cortex

2021 ◽  
Author(s):  
Alexander Shapson-Coe ◽  
Michal Januszewski ◽  
Daniel R Berger ◽  
Art Pope ◽  
Yuelong Wu ◽  
...  
Keyword(s):  
Cerebral Cortex ◽  
High Speed ◽  
Pyramidal Neurons ◽  
Three Dimensional ◽  
Cell Types ◽  
Dimensional Structure ◽  
Inhibitory Synapses ◽  
Excitatory Synapses ◽  
Split And Merge ◽  
Surgical Sample

We acquired a rapidly preserved human surgical sample from the temporal lobe of the cerebral cortex. We stained a 1 mm3 volume with heavy metals, embedded it in resin, cut more than 5000 slices at ~30 nm and imaged these sections using a high-speed multibeam scanning electron microscope. We used computational methods to render the three-dimensional structure of 50,000 cells, hundreds of millions of neurites and 130 million synaptic connections. The 1.3 petabyte electron microscopy volume, the segmented cells, cell parts, blood vessels, myelin, inhibitory and excitatory synapses, and 100 manually proofread cells are available to peruse online. Despite the incompleteness of the automated segmentation caused by split and merge errors, many interesting features were evident. Glia outnumbered neurons 2:1 and oligodendrocytes were the most common cell type in the volume. The E:I balance of neurons was 69:31%, as was the ratio of excitatory versus inhibitory synapses in the volume. The E:I ratio of synapses was significantly higher on pyramidal neurons than inhibitory interneurons. We found that deep layer excitatory cell types can be classified into subsets based on structural and connectivity differences, that chandelier interneurons not only innervate excitatory neuron initial segments as previously described, but also each others initial segments, and that among the thousands of weak connections established on each neuron, there exist rarer highly powerful axonal inputs that establish multi-synaptic contacts (up to ~20 synapses) with target neurons. Our analysis indicates that these strong inputs are specific, and allow small numbers of axons to have an outsized role in the activity of some of their postsynaptic partners.

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