• Proceedings of the KSME Conference
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• 2004.11a
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• pp.232-237
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• 2004

The tension behavior of Nicalon/CAS glass-ceramic matrix composites was investigated. Infrared (IR) thermography was employed for two different types of $Nicalon^{TM}/CAS$ composites, i.e., cross-ply and unidirectional specimens. During tensile testing, an IR camera was used for in-situ monitoring of progressive damages of $Nicalon^{TM}/CAS$ samples. The IR camera provided the temperature changes during tensile testing. Microstructural characterization using scanning electron microscopy (SEM) was performed to investigate the fracture mechanisms of $Nicalon^{TM}/CAS$ composites. In this investigation, the thermographic NDE technique was used to facilitate a better understanding of the fracture mechanisms of the $Nicalon^{TM}/CAS$ composites during tensile testing.

• Geomechanics and Engineering
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• v.23 no.6
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• pp.503-512
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• 2020

Mining activities focus on the production of mineral resources for energy generation and raw material requirements worldwide and it is a known fact that shallow reserves become scarce. For this reason, exploration of new resources proceeds consistently to meet the increasing energy and raw material demand of industrial activities. Rock mechanics has a vital role in underground mining and surface mining. Devices and instruments used in laboratory testing to determine rock mechanics related parameters might have limited sensing capability of the failure behavior. However, methodologies such as, thermal cameras, digital speckle correlation method and acoustic emission might enable to investigate the initial crack formation in detail. Regarding this, in this study, thermographic analysis was performed to analyze the failure behaviors of different types of rock specimens during uniaxial compressive strength experiments. The energy dissipation profiles of different types of rocks were characterized by the temperature difference recorded with an infrared thermal camera during experiments. The temperature increase at the failure moment was detected as 4.45℃ and 9.58℃ for andesite and gneiss-schist specimens, respectively. Higher temperature increase was observed with respect to higher UCS value. Besides, a temperature decreases of about 0.5-0.6℃ was recorded during the experiments of the marble specimens. The temperature change on the specimen is related to release of radiation energy. As a result of the porosity tests, it was observed that increase in the porosity rate from 5.65% to 20.97% can be associated to higher radiation energy released, from 12.68 kJ to 297.18 kJ.

• Journal of Korean Clinical Health Science
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• v.9 no.1
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• pp.1462-1468
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• 2021

Purpose; The purpose of this study is to objectively identify and quantify the wearer's feelings of wearing glasses. Methods: The temperature of the skin on the nose ridges and ear, and the area where the glasses were seated, was measured using a thermal imaging camera. Results: Before wearing the glasses, the temperature of the skin surface on the nasal ridge was 34.908 ± 0.875 ℃ and the temperature of the ear region was determined as 31.981 ± 0.549 ℃. The changed temperature measured at 5 minutes later after taking off the glasses showed that the nasal ridge was determined as 35.467 ± 0.342 ℃ and the ear area was determined as 32.994 ± 0.412 ℃ (p<0.05). Conclusions: In this experiment, it was revealed that the glasses cause discomfort and heat in the fitting area. It was the first attempt to study objectively and scientifically. Analysis of frame fitting points by using thermal camera is expected to be helpful when consulting a sensitive person about changes in the fit of glasses.

• The Journal of the Korea Contents Association
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• v.21 no.4
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• pp.60-66
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• 2021

Various insects live around us. Nowadays, insects are raised as a hobby at home or medicinal insects are bred in large quantities for commercial purposes. In addition, various studies have been conducted to understand the various growth characteristics of insects. In the laboratory, environmental factors were changed to do that, but only the growth characteristics could be analyzed. However, it is almost not easy to measure the skin temperature or body temperature basically needed to reveal the growth characteristics in the case of insects. In particular, the results of experiments on the skin temperature of winged insects are very insufficient. In this study, the skin temperature of insects was photographed and measured for bees and butterflies living in natural conditions under various biological activity conditions such as at rest and during flight using a thermal imaging camera, a non-contact temperature measurement method. Through quantitative analysis of the experimental results, the relationship between the biological activity characteristics of each insect and the skin temperature resulting from such biological activity was investigated. In addition, it was confirmed that honeybees maintained different skin temperatures for three important activities, such as flying, honey collection, and relocation, and that the butterflies performed a warm-up stage for flight similar to the characteristics of moths.

• Smart Structures and Systems
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• v.20 no.5
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• pp.539-548
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• 2017

Thermoelasticity is a contactless technique for measuring stress distributions in structural elements stressed by dynamic loads. This work describes the characteristics, analyzes the main causes of uncertainty and illustrates a series of operative methods for reducing its effects. More specifically, the effects of the angle of view between the thermographic camera and the surface of the object are studied, along with those due to the heat transmission by conduction between the various parts of the thing being measured as a function of the stress frequencies. The analyses, both theoretical and experimental, are aimed at defining the operational limits and optimal measurement and test conditions in relation to the measurement uncertainty that is considered tolerable in the specific application.

• Journal of the Korean Solar Energy Society
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• v.36 no.2
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• pp.1-7
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• 2016

This study was experimentally performed to analyze the growth characteristics of a plant(wax tree or privet) using the surface temperature measured from thermal images captured using a thermal camera with water and cider. To do that, this study measured every each 12 hours the surface temperature and the stem temperature of leaves attached to the plant sample until the plants wilt on summer season in the laboratory room. From the experimental results, this study revealed that the temperature of front and back of the leaves is a little different due to the pore. The mean surface temperature of a leaf in cider is $0.52^{\circ}C$ higher than that of a leaf in water. The phenomena that the leaves of plants fall could be also demonstrated using the surface temperature. Before a leaf is falling from the tree, the temperature of the stem is lowered about $2^{\circ}C$ than those of other parts in a leaf. This result can be validated from previous result performed in University of Wisconsin.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.32 no.3
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• pp.547-554
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• 2022

Recently, the field of telemedicine is growing rapidly due to the COVID-19 pandemic. However, the cost of telemedicine services is relatively high, since cloud computing, video conferencing, and cyber security should be considered. Therefore, in this paper, we design and implement a cost-effective P2P-based telemedicine system. It is implemented using the widely used the open source computing platform, Raspberry Pi, and P2P network that frees users from security problems such as the privacy leakage by the central server and DDoS attacks resulting from the server/client architecture and enables trustworthy identifying connection system using SSL protocol. Also it enables users to check the other party's status including body temperature in real time by installing a thermal imaging camera using Raspberry Pi. This allows several medical diagnoses that requires visual aids. The proposed telemedicine system will popularize telemedicine service and meet the ever-increasing demand for telemedicine.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.24 no.2
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• pp.251-255
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• 2015

Thermal deformation, such as bending and twisting, occurs among the polymer parts of air-conditioner indoor units because of repetitive temperature change during heating operation. In this study, a numerical method employing finite-element analysis to efficiently simulate the thermal deformation of an assembly is proposed. Firstly, the displacement of an actual assembly produced by thermal deformation was measured using a 3D optical measurement system. The measurement results indicated a general downward sag of the assembly, and the maximum displacement value was approximately 1 mm. The temperature distribution was measured using a thermographic camera, and the results were used as initial-temperature boundary conditions to perform temperature-displacement analysis. The simulation results agreed well with the measured data. To reduce the thermal deformation, the stiffness increased 100%. As the results, the maximum displacement decreased by approximately 5.4% and the twisting deformation of the holder improved significantly.

• Journal of Welding and Joining
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• v.32 no.5
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• pp.50-57
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• 2014

Friction Stir Welding (FSW) is a complex process with several mutually interdependent parameters. A slight difference from known settings may lead to imperfections in the stirred zone. These inhomogeneities affect on the mechanical properties of the FSWed joints. In order to prevent the failure of the welded joint it is necessary to detect the most critical defects non-destructive. Especially critical defects are wormhole and lack of penetration (LOP), because of the difficulty of detection. Online thermography is used process-accompanying for defect detecting. A thermographic camera with a fixed position relating to the welding tool measures the heating-up and the cool down of the welding process. Lap joints with sound weld seam surfaces are manufactured and monitored. Different methods of evaluation of heat distribution and intensity profiles are introduced. It can be demonstrated, that it is possible to detect wormhole and lack of penetration as well as surface defects by analyzing the welding and the cooling process of friction stir welding by passive online thermography measurement. Effects of these defects on mechanical properties are shown by tensile testing.

• Journal of People, Plants, and Environment
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• v.22 no.3
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• pp.233-239
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• 2019

This study was conducted in order to predict the vase life of cut lily 'Woori Tower' flowers using a non-destructive thermal imaging technique. It was found that the temperature of cut lily flowers was maintained at 20℃ and was slightly lower than the air temperature until they bloomed. On the 11th day, when flowers bloomed, the temperature of leaves and flowers was measured to be 18.75±0.38℃ and 19.23±0.32℃ respectively, and their difference with ambient temperature was over 3℃. The flower temperature increased slightly when the vase life of cut lily flowers ended, and the temperature difference between the air and leaf temperature (1.77℃) and between the air and flower temperature (1.39℃) got smaller. No visible aging symptom was observed, but it was found that the temperature had risen due to water losses and less functional stomata. The vase life of cut lily flowers can be predicted based on changes in temperature and it will be also possible to predict the potential quality and vase life of cut flowers before harvesting them in greenhouses.