scholarly journals The Study of the Electrospark Coating Effect on the Heat Removal Property of Hard Alloy

2020 ◽  
pp. 133-143
Author(s):  
Yaroslav A. Vostrikov ◽  
Sardana A. Sleptsova
Keyword(s):  
Hard Alloy ◽  
Protective Coating ◽  
Heat Removal ◽  
Front Surface ◽  
Heat Propagation ◽  
Cutting Edge ◽  
Maximum Temperature ◽  
Thermal Imager ◽  
Surface Cooling ◽  
Electrospark Coating

The effect of a protective coating on the heat removal properties of a cutting plate made of VK8 tungsten-containing hard alloy has been studied. The article provides a sequence of measurements made by a thermal imager and a thermograph to install a mechanism for heat removal by a protective coating. The factors affecting the fault in temperature measurements in a static experiment by means of a thermal imager are described. The time to maximum temperature transferred from the heated counterbody to the hard alloy with and without coating has been obtained. The exposure time of the maximum temperature transmitted from the counterbody to the alloys under study has been fixed. It has been demonstrated that a multilayer electrospark coating based on Ni, Cu, Fe, Cr, W reduces the maximum temperature under the same test conditions by 42%, while the surface cooling rate at the point close to the cutting edge increases by 53%. The data obtained show the effect of the protective coating on the heat removal property of the hard alloy. The time of heat propagation over the entire surface of the test sample and the cooling time have been studied by means of a thermograph. There is a temperature difference of 103°С for the alloy without coating that has been calculated simultaneously between the points on the cutting edge and at a distance of 2 mm lower along the front surface, while for the alloy with a protective coating the difference was 79°С, it is less by 24%. The thermograms of alloys with and without coating are clearly shown at time to maximum temperature on the surface. The work of the coating to remove heat from the point of contact with the heated counterbody has been proven, and the heat removal property is explained by the composition of the coating obtained by electrospark alloying with electrodes based on Cu, Ni, Fe, W, and Cr

scholarly journals Experimental Study on Infrared Temperature Characteristics and Failure Modes of Marble with Prefabricated Holes under Uniaxial Compression

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 713
Author(s):  
Yanyan Peng ◽  
Qunchao Lin ◽  
Manchao He ◽  
Chun Zhu ◽  
Haijiang Zhang ◽  
...  
Keyword(s):  
Uniaxial Compression ◽  
Failure Modes ◽  
Rock Sample ◽  
Vertical Axis ◽  
Maximum Temperature ◽  
Thermal Imager ◽  
Infrared Thermal Imaging ◽  
Average Temperature ◽  
Observation Area ◽  
Evolution Behavior

In rock engineering, it is of great significance to study the failure mechanical behavior of rocks with holes. Using a combination of experiment and infrared detection, the strength, deformation, and infrared temperature evolution behavior of marble with elliptical holes under uniaxial compression were studied. The test results showed that as the vertical axis b of the ellipse increased, the peak intensity first decreased and then increased, and the minimum value appeared when the horizontal axis was equal to the vertical axis. The detection results of the infrared thermal imager showed that the maximum temperature, minimum temperature, and average temperature of the observation area in the loading stage showed a downward trend, and the range of change was between 0.02 °C and 1 °C. It was mainly due to the accumulation of energy in the loading process of the rock sample that caused the surface temperature of the specimen to decrease. In the brittle failure stage, macroscopic cracks appeared on the surface of the rock sample, which caused the energy accumulated inside to dissipate, thereby increasing the maximum temperature and average temperature of the rock sample. The average temperature increase was about 0.05 °C to about 0.19 °C. The evolution of infrared temperature was consistent with the mechanical characteristics of rock sample failure, indicating that infrared thermal imaging technology can provide effective monitoring for the study of rock mechanics. The research in this paper provides new ideas for further research on the basic characteristics of rock failure under uniaxial compression.

scholarly journals Extreme heat in India and anthropogenic climate change

2018 ◽  
Vol 18 (1) ◽  
pp. 365-381 ◽  
Author(s):  
Geert Jan van Oldenborgh ◽  
Sjoukje Philip ◽  
Sarah Kew ◽  
Michiel van Weele ◽  
Peter Uhe ◽  
...  
Keyword(s):  
Air Pollution ◽  
Global Warming ◽  
Health Effects ◽  
Climate Models ◽  
Decadal Variability ◽  
Heat Waves ◽  
Health Impact ◽  
Heat Index ◽  
Maximum Temperature ◽  
Surface Cooling

Abstract. On 19 May 2016 the afternoon temperature reached 51.0 °C in Phalodi in the northwest of India – a new record for the highest observed maximum temperature in India. The previous year, a widely reported very lethal heat wave occurred in the southeast, in Andhra Pradesh and Telangana, killing thousands of people. In both cases it was widely assumed that the probability and severity of heat waves in India are increasing due to global warming, as they do in other parts of the world. However, we do not find positive trends in the highest maximum temperature of the year in most of India since the 1970s (except spurious trends due to missing data). Decadal variability cannot explain this, but both increased air pollution with aerosols blocking sunlight and increased irrigation leading to evaporative cooling have counteracted the effect of greenhouse gases up to now. Current climate models do not represent these processes well and hence cannot be used to attribute heat waves in this area. The health effects of heat are often described better by a combination of temperature and humidity, such as a heat index or wet bulb temperature. Due to the increase in humidity from irrigation and higher sea surface temperatures (SSTs), these indices have increased over the last decades even when extreme temperatures have not. The extreme air pollution also exacerbates the health impacts of heat. From these factors it follows that, from a health impact point of view, the severity of heat waves has increased in India. For the next decades we expect the trend due to global warming to continue but the surface cooling effect of aerosols to diminish as air quality controls are implemented. The expansion of irrigation will likely continue, though at a slower pace, mitigating this trend somewhat. Humidity will probably continue to rise. The combination will result in a strong rise in the temperature of heat waves. The high humidity will make health effects worse, whereas decreased air pollution would decrease the impacts.

Design and Optimization of a Composite Heat Spreader to Improve the Thermal Management of a 3D Integrated Circuit

2021 ◽  
Author(s):  
Andisheh Tavakoli ◽  
Kambiz Vafai
Keyword(s):  
Thermal Conductivity ◽  
Heat Sink ◽  
Variable Temperature ◽  
Heat Removal ◽  
High Conductivity ◽  
High Thermal Conductivity ◽  
Maximum Temperature ◽  
Optimal Distribution ◽  
Heat Spreader ◽  
The Impact

Abstract The present study analyzes the optimal distribution of a limited amount of high thermal conductivity material to enhance the heat removal of circular 3D integrated circuits, IC. The structure of the heat spreader is designed as a composite of high thermal conductivity (Boron Arsenide) and moderate thermal conductivity (copper) materials. The volume ratio of high-conductivity inserts to the total volume of the spreader is set at a fixed pertinent ratio. Two different boundary conditions of constant and variable temperature are considered for the heat sink. To examine the impact of adding high-conductivity inserts on the cooling performance of the heat spreader, various patterns of the single and double ring inserts are studied. A parametric study is performed to find the optimal location of the rings. Moreover, the optimal distribution of the high-conductivity material between the inner and outer rings is found. The results show that for the optimal conditions, the maximum temperature of the 3D IC is reduced up to 10%; while the size of the heat sink, and heat spreader can be diminished by as much as 200%.

Efficiency Enhancement of Photovoltaic/Thermal Module Using Front Surface Cooling Technique in Winter and Summer Seasons: An Experimental Investigation

2019 ◽  
Vol 141 (9) ◽  
Author(s):  
Himanshu Sainthiya ◽  
Narendra S. Beniwal
Keyword(s):  
Solar Cell ◽  
Surface Water ◽  
Surface Temperature ◽  
Front Surface ◽  
Climatic Conditions ◽  
Back Surface ◽  
Water Cooling ◽  
Performance Parameters ◽  
Surface Cooling ◽  
Overall Efficiency

This paper presents the effect of the front surface water cooling on performance parameters (solar cell temperature, back surface temperature, outlet water temperature, electrical efficiency, overall efficiency, etc.) of photovoltaic/thermal (PV/T) module in both winter and summer seasons in Indian climatic conditions. A mathematical model of PV/T module considering energy balance equations has also been presented. A comparative analysis of performance parameters obtained analytically and experimentally has also been presented. A fair agreement has also been found between analytical and experimental results which is supported by correlation coefficient of approximately unity and root mean square error of 10–14%. By front surface water cooling, solar cell and back surface temperature of PV/T module have been found to decrease considerably which in turn resulted in enhanced electrical and overall efficiency of module in winter and summer seasons.

EXPERIMENTAL STUDIES OF THE HEATING TEMPERATURE OF THE GREENHOUSE RADIATOR INSTALLATIONS

2020 ◽  
Vol 15 (1) ◽  
pp. 76-80
Author(s):  
Nadezhda Kondrat'eva ◽  
Dmitriy Filatov ◽  
Pavel Terent'ev ◽  
Bulat Ziganshin
Keyword(s):  
Energy Efficiency ◽  
Supply Voltage ◽  
Heating Temperature ◽  
Experimental Studies ◽  
Maximum Temperature ◽  
Thermal Imager ◽  
Voltage Level ◽  
Radiation Sources ◽  
Measurement Results ◽  
Nominal Mode

The thermal regime of plants determines the temperature of the environment, the evaporation of moisture by plants, and the heating of plants by radiation from irradiation plants. Today, induction and LED greenhouse irradiators are promising for replacing irradiators with sodium lamps in terms of energy efficiency. Experimental studies were performed to assess the possibility of proximity of irradiators with induction lamps and LED irradiators to plants to increase their level of irradiation, in comparison with sodium radiation sources. When setting up the experiment, a complex was used, including a Fluke ti32 thermal imager, PHO-250-2-M linear autotransformer, 220V power supply, and a greenhouse irradiator. Processing of the measurement results was carried out in the Fluke SmartView 3.1 program. The heating temperature was determined when reaching the nominal mode, with the nominal mode of operation of the irradiators, with a change in the supply voltage level. Sodium and induction irradiators heat up to a maximum temperature 10 times faster than LED ones. The heating temperature of optical radiation sources with sodium lamps is 5 times higher than LED and 2.5 times higher than induction. A change in the supply voltage level affects the heating temperature of the sodium irradiator with electromagnetic ballasts, the heating temperature of sodium and induction irradiators with electronic ballasts, as well as LED irradiators, remains unchanged and equal to the nominal value at a supply voltage level of ± 10% of Unom.. Low heating temperatures of induction and LED irradiators can reduce the height of their suspension and bring them closer to plants, which will increase the irradiation of plants by increasing the level of illumination or reduce the power of irradiators, that is, increase the energy efficiency of irradiation systems

Natural Convection in a Cylindrical Porous Enclosure With Internal Heat Generation

1989 ◽  
Vol 111 (4) ◽  
pp. 916-925 ◽  
Author(s):  
V. Prasad ◽  
A. Chui
Keyword(s):  
Nusselt Number ◽  
Natural Convection ◽  
Rayleigh Number ◽  
Aspect Ratio ◽  
Numerical Study ◽  
Vertical Wall ◽  
Internal Heat ◽  
Heat Removal ◽  
Maximum Temperature ◽  
Wall Boundary Conditions

A numerical study is performed on natural convection inside a cylindrical enclosure filled with a volumetrically heated, saturated porous medium for the case when the vertical wall is isothermal and the horizontal walls are either adiabatic or isothermally cooled. When the horizontal walls are insulated, the flow in the cavity is unicellular and the temperature field in upper layers is highly stratified. However, if the top wall is cooled, there may exist a multicellular flow and an unstable thermal stratification in the upper region of the cylinder. Under the influence of weak convection, the maximum temperature in the cavity can be considerably higher than that predicted for pure conduction. The local heat flux on the bounding walls is generally a strong function of the Rayleigh number, the aspect ratio, and the wall boundary conditions. The heat removal on the cold upper surface decreases with the aspect ratio, thereby increasing the Nusselt number on the vertical wall. The effect of Rayleigh number is, however, not straightforward. Several correlations are presented for the maximum cavity temperature and the overall Nusselt number.

scholarly journals Theoretical bases of calculation of energy parameters of laser radiation for thermotherapy of Baker's cyst.

2017 ◽  
Vol 10 (4) ◽  
pp. 304-309
Author(s):  
Andrew V Zhilyakov ◽  
S A Chernyadiev ◽  
A V Aretinskiy ◽  
N I Sivkova ◽  
N Yu Korobova ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Laser Radiation ◽  
Thermal Effects ◽  
Negative Impact ◽  
Heat Removal ◽  
Thermal Exposure ◽  
Thermal Imager ◽  
Radiation Emission ◽  
Lidocaine Solution ◽  
Series Of Experiments

Actuality: Interstitial application of light energy to pathological tissues of small volume always raises concerns about the possible negative impact of excessive thermal effects on the surrounding unchanged structures. At the same time, insufficient thermal exposure does not allow achieving the desired result of manipulation. In particular, with a similar problem, there are surgeons performing laser-induced thermotherapy of cysts of different localization. Objective: Determine the time to reach the desired temperature required for the irreversible coagulation of the wall of the Baker cyst, depending on the power of the laser radiation and the volume of the intracystic fluid. Materials and methods: Several series of experiments were carried out in which different volumes of aqueous lidocaine solution were heated in disposable syringes by laser radiation fed along a flexible light-bearing fiber. Registration of infrared radiation from this system was performed by a portable thermal imager CONDTROL IR-CAM (Russia). The time for heating the syringe to 70 ° C was measured at different radiation powers. Results: In all series of experiments, a predetermined temperature of 70 ° C was achieved, providing instantaneous protein coagulation. Attention is drawn to the fact that the calculated time by the formula (ideal) in all cases is less, which can be explained by the effect of heat removal from the walls of syringes. The higher the power of laser radiation, the less the effect of heat removal on the heating rate of the aqueous solution, and, accordingly, the time to reach the set temperature. Conclusion. In the energy regimes and volumes of the aqueous solution studied, the optical fiber with end radiation emission is not capable of causing carbonization and damage to surrounding tissues. Accordingly, contactless perforation of the cyst wall by laser radiation with a wavelength of 1.47 μm is impossible. The obtained data testify to the advisability of calculating the energy to reach the set temperature and keeping it for a period sufficient for coagulation transformation of the more external layers of education

scholarly journals THE MAPPING OF SUBSURFACE TEMPERATURE AND STUDY OF GEOTHERMAL GRADIENT ANOMALY IN THE DISCHARGE AREA IN NORTH SULAWESI

2020 ◽  
Vol 6 (1) ◽  
pp. 1-4
Author(s):  
Donny Royke Wenas ◽  
Cyrke A.N. Bujung
Keyword(s):  
Heat Source ◽  
Geothermal Gradient ◽  
Heat Propagation ◽  
Source Zone ◽  
Maximum Temperature ◽  
Heat Transmission ◽  
North Sulawesi ◽  
Subsurface Layers ◽  
Remote Sensing Techniques ◽  
Location Mapping

The aim of this research is to measure and mapping the temperature distribution in several subsurface layers in the manifestation of geothermal warm ground and steaming ground, and analyze the geothermal subsurface gradient, to determine the heat source zone, and the pattern and direction of heat flow from subsurface to surface in  Hydrothermal area of Minahasa Indonesia. The method used is direct measurement in the field. To determine the coordinates of geothermal manifestations and location mapping, using remote sensing techniques. The results showed that at a depth of 200 cm the temperature reaches 102 0C and the heat source comes from the northeast and from the south. At a depth of 150 cm the temperature varies from 52 to 100 0C with an even distribution in almost every direction. At a depth of 50 to 100 cm the maximum temperature reaches 98 0C with heat propagation starting to concentrate then northeast, and then out to the surface in the northeast. The pattern of heat transmission is almost linear along with the geothermal gradient.

Efficiency Improvement of a Photovoltaic Module Using Front Surface Cooling Method in Summer and Winter Conditions

2018 ◽  
Vol 140 (6) ◽  
Author(s):  
Himanshu Sainthiya ◽  
Narendra S. Beniwal ◽  
Navneet Garg
Keyword(s):  
Output Power ◽  
Cooling System ◽  
Front Surface ◽  
Weather Conditions ◽  
Photovoltaic Module ◽  
Surface Cooling ◽  
Cell Efficiency ◽  
Pumping System ◽  
Winter Conditions ◽  
Cooling Method

Photovoltaic (PV) cells exhibit long-term degradation, when its temperature exceeds a certain limit. On the other hand, decreasing the temperature results in lower PV cell efficiency. The aim of this paper is to demonstrate the improvements in the output power and efficiency of PV modules using a cooling system based on flowing water on the front surface. Front surface cooling method with the help of a water pumping system is one of the most promising methods for cooling the PV cells. With poly-crystalline PV cells, different water flow rates are experimented, and the output power and the efficiency are computed for different weather conditions. These experiments yield that the cell efficiency is improved by approximately 27.3% in winter conditions and 27.6% in summer conditions.

scholarly journals Recognition of Human Face Regions under Adverse Conditions—Face Masks and Glasses—In Thermographic Sanitary Barriers through Learning Transfer from an Object Detector

Machines ◽  
2022 ◽  
Vol 10 (1) ◽  
pp. 43
Author(s):  
Joabe R. da Silva ◽  
Gustavo M. de Almeida ◽  
Marco Antonio de S. L. Cuadros ◽  
Hércules L. M. Campos ◽  
Reginaldo B. Nunes ◽  
...  
Keyword(s):  
Learning Transfer ◽  
Region Of Interest ◽  
Maximum Temperature ◽  
Thermal Imager ◽  
Human Face ◽  
Disease Symptoms ◽  
Adverse Conditions ◽  
Shared Spaces ◽  
Body Surface Temperature ◽  
Areas Of Interest

The COVID-19 pandemic has detrimentally affected people’s lives and the economies of many countries, causing disruption in the health, education, transport, and other sectors. Several countries have implemented sanitary barriers at airports, bus and train stations, company gates, and other shared spaces to detect patients with viral symptoms in an effort to contain the spread of the disease. As fever is one of the most recurrent disease symptoms, the demand for devices that measure skin (body surface) temperature has increased. The thermal imaging camera, also known as a thermal imager, is one such device used to measure temperature. It employs a technology known as infrared thermography and is a noninvasive, fast, and objective tool. This study employed machine learning transfer using You Only Look Once (YOLO) to detect the hottest temperatures in the regions of interest (ROIs) of the human face in thermographic images, allowing the identification of a febrile state in humans. The algorithms detect areas of interest in the thermographic images, such as the eyes, forehead, and ears, before analyzing the temperatures in these regions. The developed software achieved excellent performance in detecting the established areas of interest, adequately indicating the maximum temperature within each region of interest, and correctly choosing the maximum temperature among them.

Sign in / Sign up

Export Citation Format

Share Document