Flow Maps in the Boiling Process in Domestic Refrigerators

2021 ◽  
pp. 419-432
Author(s):  
Fernando Toapanta-Ramos ◽  
César Nieto-Londoño ◽  
Elizabeth Suquillo-Goméz ◽  
William Quitiaquez
Keyword(s):  
Flow Maps ◽  
Boiling Process

THE MECHANISM OF RAISING AND QUANTIFICATION OF SPECIFIC HEAT FLUX AT BOILING OF NANOFLUIDS IN FREE CONVECTION CONDITIONS

2017 ◽  
pp. 25-34
Author(s):  
V.N. Moraru
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Capacity ◽  
Specific Heat ◽  
Chemical Properties ◽  
Heating Surface ◽  
Physical Models ◽  
Superheated Liquid ◽  
Two Phase ◽  
Boiling Process

The results of our work and a number of foreign studies indicate that the sharp increase in the heat transfer parameters (specific heat flux q and heat transfer coefficient _) at the boiling of nanofluids as compared to the base liquid (water) is due not only and not so much to the increase of the thermal conductivity of the nanofluids, but an intensification of the boiling process caused by a change in the state of the heating surface, its topological and chemical properties (porosity, roughness, wettability). The latter leads to a change in the internal characteristics of the boiling process and the average temperature of the superheated liquid layer. This circumstance makes it possible, on the basis of physical models of the liquids boiling and taking into account the parameters of the surface state (temperature, pressure) and properties of the coolant (the density and heat capacity of the liquid, the specific heat of vaporization and the heat capacity of the vapor), and also the internal characteristics of the boiling of liquids, to calculate the value of specific heat flux q. In this paper, the difference in the mechanisms of heat transfer during the boiling of single-phase (water) and two-phase nanofluids has been studied and a quantitative estimate of the q values for the boiling of the nanofluid is carried out based on the internal characteristics of the boiling process. The satisfactory agreement of the calculated values with the experimental data is a confirmation that the key factor in the growth of the heat transfer intensity at the boiling of nanofluids is indeed a change in the nature and microrelief of the heating surface. Bibl. 20, Fig. 9, Tab. 2.

scholarly journals A Driver’s Visual Attention Prediction Using Optical Flow

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3722
Author(s):  
Byeongkeun Kang ◽  
Yeejin Lee
Keyword(s):  
Visual Attention ◽  
Optical Flow ◽  
Prediction Models ◽  
Apparent Movement ◽  
Image Sequences ◽  
Motion Information ◽  
Accuracy Improvement ◽  
Flow Maps ◽  
Current State ◽  
Motion Features

Motion in videos refers to the pattern of the apparent movement of objects, surfaces, and edges over image sequences caused by the relative movement between a camera and a scene. Motion, as well as scene appearance, are essential features to estimate a driver’s visual attention allocation in computer vision. However, the fact that motion can be a crucial factor in a driver’s attention estimation has not been thoroughly studied in the literature, although driver’s attention prediction models focusing on scene appearance have been well studied. Therefore, in this work, we investigate the usefulness of motion information in estimating a driver’s visual attention. To analyze the effectiveness of motion information, we develop a deep neural network framework that provides attention locations and attention levels using optical flow maps, which represent the movements of contents in videos. We validate the performance of the proposed motion-based prediction model by comparing it to the performance of the current state-of-art prediction models using RGB frames. The experimental results for a real-world dataset confirm our hypothesis that motion plays a role in prediction accuracy improvement, and there is a margin for accuracy improvement by using motion features.

scholarly journals Combined Perfusion and Permeability Imaging Reveals Different Pathophysiologic Tissue Responses After Successful Thrombectomy

2021 ◽  
Author(s):  
Arne Potreck ◽  
Matthias A. Mutke ◽  
Charlotte S. Weyland ◽  
Johannes A. R. Pfaff ◽  
Peter A. Ringleb ◽  
...  
Keyword(s):  
Clinical Outcome ◽  
Blood Brain Barrier ◽  
Hemorrhagic Transformation ◽  
Brain Barrier ◽  
Dynamic Susceptibility ◽  
Blood Brain Barrier Disruption ◽  
Flow Maps ◽  
Blood Brain ◽  
Patients At Risk ◽  
Brain Barrier Disruption

AbstractDespite successful recanalization of large-vessel occlusions in acute ischemic stroke, individual patients profit to a varying degree. Dynamic susceptibility-weighted perfusion and dynamic T1-weighted contrast-enhanced blood-brain barrier permeability imaging may help to determine secondary stroke injury and predict clinical outcome. We prospectively performed perfusion and permeability imaging in 38 patients within 24 h after successful mechanical thrombectomy of an occlusion of the middle cerebral artery M1 segment. Perfusion alterations were evaluated on cerebral blood flow maps, blood-brain barrier disruption (BBBD) visually and quantitatively on ktrans maps and hemorrhagic transformation on susceptibility-weighted images. Visual BBBD within the DWI lesion corresponded to a median ktrans elevation (IQR) of 0.77 (0.41–1.4) min−1 and was found in all 7 cases of hypoperfusion (100%), in 10 of 16 cases of hyperperfusion (63%), and in only three of 13 cases with unaffected perfusion (23%). BBBD was significantly associated with hemorrhagic transformation (p < 0.001). While BBBD alone was not a predictor of clinical outcome at 3 months (positive predictive value (PPV) = 0.8 [0.56–0.94]), hypoperfusion occurred more often in patients with unfavorable clinical outcome (PPV = 0.43 [0.10–0.82]) compared to hyperperfusion (PPV = 0.93 [0.68–1.0]) or unaffected perfusion (PPV = 1.0 [0.75–1.0]). We show that combined perfusion and permeability imaging reveals distinct infarct signatures after recanalization, indicating the severity of prior ischemic damage. It assists in predicting clinical outcome and may identify patients at risk of stroke progression.

Development of low-cost C/C, related technology using a film-boiling process

Carbon ◽  
2021 ◽  
Vol 175 ◽  
pp. 609
Author(s):  
Hiroshi Yamauchi ◽  
Michimasa Uda ◽  
Haruhiko Soeda
Keyword(s):  
Low Cost ◽  
Film Boiling ◽  
Boiling Process

Effects of Gap Geometry and Gravity on Boiling Around a Constrained Bubble in 2-Propanol/Water Mixtures

2006 ◽  
Vol 129 (2) ◽  
pp. 114-123
Author(s):  
Chen-li Sun ◽  
Van P. Carey
Keyword(s):  
Heat Flux ◽  
Heated Surface ◽  
Molar Fraction ◽  
Nucleate Boiling ◽  
Confined Space ◽  
Cold Surface ◽  
Boiling Regime ◽  
Wall Superheat ◽  
Boiling Process ◽  
Lower Heat

In this study, boiling experiments were conducted with 2-propanol/water mixtures in confined gap geometry under various levels of gravity. The temperature field created within the parallel plate gap resulted in evaporation over the portion of the vapor-liquid interface of the bubble near the heated surface, and condensation near the cold surface. Full boiling curves were obtained and two boiling regimes—nucleate boiling and pseudofilm boiling—and the transition condition, the critical heat flux (CHF), were identified. The observations indicated that the presence of the gap geometry pushed the nucleate boiling regime to a lower superheated temperature range, resulting in correspondingly lower heat flux. With further increases of wall superheat, the vapor generated by the boiling process was trapped in the gap to blanket the heated surface. This caused premature occurrence of CHF conditions and deterioration of heat transfer in the pseudo-film boiling regime. The influence of the confined space was particularly significant when greater Marangoni forces were present under reduced gravity conditions. The CHF value of x (molar fraction)=0.025, which corresponded to weaker Marangoni forces, was found to be greater than that of x=0.015 with a 6.4mm gap.

Evaluation of boiling process on the basis of electrical resistance of petroleum fractions

1987 ◽  
Vol 23 (8) ◽  
pp. 393-395
Author(s):  
B. A. Zimin ◽  
I. I. Stolonogov ◽  
M. A. Gusev ◽  
A. N. Nesterov
Keyword(s):  
Electrical Resistance ◽  
Petroleum Fractions ◽  
Boiling Process

PENGARUH LAMA PEREBUSAN SIMPLISIA DAUN APAH (Albertisia papuana Becc.) YANG DIGUNAKAN SEBAGAI PENYEDAP MAKANAN OLEH MASYARAKAT KAB. TANA TIDUNG TERHADAP ANGKA CEMARAN MIKROBA

2017 ◽  
Vol 2 (1) ◽  
pp. 22
Author(s):  
Rosnah Rosnah ◽  
Medi Hendra ◽  
Eko Kusumawati
Keyword(s):  
Microbial Contamination ◽  
Colony Growth ◽  
Dilution Series ◽  
Randomized Design ◽  
Significant Difference ◽  
Boiling Process ◽  
Completely Randomized Design

The purpose of this study is to determine the effect of long simplicia Apah’s leaves (Albertisia papuana Becc.) that’s used as a food’s flavoring by people of Kab. Tana Tidung against microbial contamination numbers. The design of research used a pattern completely randomized design (RAL), with a dilution series of samples 10-8, 10-9 and 10-10 and different boiling’s level (5, 10, 15, 20 and 25 minutes). The results obtained that the longer of boiling process is used, then the less the number of microbial contamination of colony growth. Average number of microbial contamination in samples in the boiling of 5 minutes is 92 x 1010 microbial colonies, in boiling 10 minutes is 87 x 1010 microbial colonies, in boiling 15 minutes is 56 x 1010 microbial colonies, in boiling 20 min is 44 x 1010 colonies of microbes and the boiling simplicia infuse for 25 minutes is 33 x 1010 colonies of microbes. Based of Analysis variance variety in each treatment showed that in boiling 20 minutes and 25 minutes showed real significant difference (p <0.05), but the boiling 5, 10 and 15 minutes there was no significant difference (P> 0.05). The results of the Anova, showed that in boiling treatment of simplicia Apah’s leaves (Albertisia papuana Becc.) significantly affects the growth of microbial colonies. Analysis of Least Significant Difference (LSD) at the level of 95%, the result that the effects of long boiling the simplicia Apah’s leaves (Albertisia papuana Becc.) which is used as a food flavoring by people of Kab. Tana Tidung, significant effect on the numbers of microbial contamination

Abstract T P41: Determination of Collateral Supply Patterns Using MR or CT Perfusion Imaging

Stroke ◽  
2014 ◽  
Vol 45 (suppl_1) ◽  
Author(s):  
Cihat Eldeniz ◽  
Yueh Lee ◽  
Maria Gisele Matheus ◽  
Jeffery Keith Smith ◽  
James Faber ◽  
...  
Keyword(s):  
Perfusion Imaging ◽  
Ct Perfusion ◽  
Mapping Method ◽  
Collateral Flow ◽  
Scoring Method ◽  
Flow Mapping ◽  
Flow Maps ◽  
Ct Perfusion Imaging ◽  
Ischemic Tissue ◽  
Flow Information

Introduction: In this study, we sought to develop a collateral flow mapping method based on MR or CT perfusion imaging and compare this method with the digital subtraction angiography (DSA) method. Methods: Ischemic tissue supplied by collateral flow is likely to have delayed tracer arrival but relatively normal flow. In this study, abnormal Tmax (> 6 sec), MTT (4 sec or greater than unaffected hemisphere) and CBF (<40% of unaffected hemisphere) were labeled with green, red and blue, respectively (Fig. A). Any perfusion patterns can then be represented by a combination of this integrated RGB maps (Integrated Collateral flow Maps, iCMaps). 24 patients were included in this study. DSA images were obtained from all patients, whereas MR and CT perfusion images were acquired from 15 and 9 patients, respectively, within 30 hours after MCA occlusion. iCMaps collateral flow was scored independently as follows. iCMaps without any perfusion abnormality was assigned “1”. iCMaps with white as the dominant perfusion pattern was assigned a “5”; while those with a dominant green and yellow pattern were assigned a “2” or a “3”, depending on the relative green and yellow volume. Finally, iCMaps with a white region surrounded with yellow and green was assigned a “4”. Examples of iCMaps scoring are shown in Fig. B. Using a DSA scoring method in the literature5, a score of 1-5 was given independently based on the degree of retrograde collateralization (5: poor collateralization). Results: Good correlation was found between the MR perfusion iCMaps and DSA (DSA=0.70*MR iCMaps+0.54, R=0.75). Moderate correlation was obtained between the CT perfusion iCMaps and DSA (DSA=0.51*CT iCMaps+1.9, R=0.56). Conclusions: Based on the different characteristics of Tmax, MTT and CBF maps, the proposed MR or CT perfusion based iCMaps method can provide DSA comparable collateral flow information.

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