• Journal of the Korean institute of surface engineering
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• v.55 no.3
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• pp.173-179
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• 2022

This study presents a roll-to-roll process which is capable of Ag nanowire (AgNW) transfer from polyethylene terephthalate (PET) film to polycarbonate (PC) film. We developed a roll-to-roll machine that consists of two film suppliers, a coater of photo-curable resin, a film laminator, an ultraviolet (UV) exposure unit, and a film winder to facilitate large-area electrode transfer between different flexible substates. Using the process, optimal fabrication condition was investigated by parametric experiments in terms of the UV exposure time, number of thermal cycling, and exposure time of high temperature and humidity. A fabricated AgNW on PC film showed sheet resistance of 52 Ω/sq and optical transmittance of approximately 80 % over a range of visible light.

• Elastomers and Composites
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• v.55 no.1
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• pp.51-58
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• 2020

In this study, the thermal oxidation of raw natural rubber (NR) was investigated under controlled conditions by optical image and fourier transform infrared (FT-IR) analysis. The thermal oxidation was performed on a transparent thin film of raw NR coated on a KBr window in a dark chamber at 80℃ under low humidity conditions to completely exclude moisture and restrict light oxidation. Images of the thin film of raw NR were obtained before and after thermal oxidation. FT-IR absorption spectra were measured in the transmission mode at different thermal exposure times. The thermal oxidation of NR was examined by the changes in the absorption peaks at 3449, 1736, 1447, 1377, 1242, 1072, and 833 cm^-1, which corresponded to a hydroxyl group (-OH), a carbonyl group (-C=O) from an aldehyde and a ketone, a methylene group (-CH₂-), a methyl group (-CH₃), a carbon-oxygen single bond (-C-O) from an epoxide, a carbon-oxygen bond (-C-O) from an ether, an alcohol, a peroxide, or a cyclic peroxide, and a cis-methine group (cis-CCH₃=CH-), respectively. In the initial stage of thermal oxidation, two different types of free radicals were produced quickly and randomly by the homolytic cleavage of a double bond and allylic hydrogen abstraction. Aldehydes and ketones were formed from chain scissions of the double bonds and alcohols were produced from allylic hydrogen abstraction at the methylene or methyl groups. Two reactions seemed to proceed competitively with each other. At a later stage, oxidative crosslinks seemed to dominate through the combination of free radicals such as an allyl radical (CH=CHCH₂·), alkoxy radical (RO·), and peroxy radical (ROO·) and the reaction of a hydroperoxide (-ROOH) with a double bond. The image obtained after thermal oxidation showed hardening without cracks. Based on these observations, a plausible two-step mechanism was suggested for chain hardening caused by the thermal oxidation.

• Journal of the Korea Concrete Institute
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• v.17 no.5 s.89
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• pp.821-828
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• 2005

To investigate the role of RH and temperature on the transport of chloride in the concrete, two groups of specimens were configured. For both groups, mix design was based on w/c=0.45, $400kg/m^3$ cement, $794kg/m^3$ fine aggregate and $858kg/m^3$ coarse aggregate. After specimen fabrication these were exposed to four different RH (35, 55, 75 and $95\%$ RH) and temperature (0, 20, 30 and $40^{\circ}C$) conditions. After 3 and 6 months $15\%$ NaCl exposure 5mm cores were taken. These cores were sliced and individual cores were ground to powder. In addition, to evaluate the effect of temperature on the chloride binding some powder samples were leached in the each of four temperature chambers. Chloride titration fur these was performed using FDOT acid titration method. Based upon the resultant data conclusions were reached regarding that 1) effective diffusion coefficient, $D_e$, increased with increasing exposure RH, suggesting that the size and number of water paths increased with elevated moisture content in the specimens, 2) $D_e$ increased with increasing temperature in the range of 0 to $40^{\circ}C$ possibly by elevated thermal activation of chloride ions and reduced chloride binding at higher temperature, 3) water soluble chloride concentration, $[Cl^-]_s$, increased with increasing temperature, and 4) chloride concentration profile for initially dry concrete specimens was higher than for the initially wet ones indicating pronounced capillary suction (sorption) occurred for the dry concrete specimens.

• Current Photovoltaic Research
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• v.9 no.2
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• pp.36-44
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• 2021

To endorse the reliability and durability of the solar photovoltaic (PV) device several tests were conducted before exposing to the outdoor field in a non-ideal condition. The PV module has high probability that intend to perform adequately for 30 years under operating conditions. To evaluate the long term performance of the PV module in diversified terrestrial conditions, one should use the outdoor performance data. However, no one wants to wait for 25 years to determine the module reliability. The accelerating stress tests performing in the laboratory by mimicking different field conditions are thus important to understand the performance of a PV module. In this review, we will discuss briefly about different accelerating stress types, levels and prioritization that are used to evaluate the PV module reliability and durability before using them in real field.

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.11
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• pp.1585-1592
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• 2016

The present experiment was conducted to evaluate the effect of simulated heat stress on digestibility and methane ($CH_4$) emission. Four non-lactating crossbred cattle were exposed to $25^{\circ}C$, $30^{\circ}C$, $35^{\circ}C$, and $40^{\circ}C$ temperature with a relative humidity of 40% to 50% in a climatic chamber from 10:00 hours to 15:00 hours every day for 27 days. The physiological responses were recorded at 15:00 hours every day. The blood samples were collected at 15:00 hours on 1st, 6th, 11th, 16th, and 21st days and serum was collected for biochemical analysis. After 21 days, fecal and feed samples were collected continuously for six days for the estimation of digestibility. In the last 48 hours gas samples were collected continuously to estimate $CH_4$ emission. Heat stress in experimental animals at $35^{\circ}C$ and $40^{\circ}C$ was evident from an alteration (p<0.05) in rectal temperature, respiratory rate, pulse rate, water intake and serum thyroxin levels. The serum lactate dehydrogenase, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase activity and protein, urea, creatinine and triglyceride concentration changed (p<0.05), and body weight of the animals decreased (p<0.05) after temperature exposure at $40^{\circ}C$. The dry matter intake (DMI) was lower (p<0.05) at $40^{\circ}C$ exposure. The dry matter and neutral detergent fibre digestibilities were higher (p<0.05) at $35^{\circ}C$ compared to $25^{\circ}C$ and $30^{\circ}C$ exposure whereas, organic matter (OM) and acid detergent fibre digestibilities were higher (p<0.05) at $35^{\circ}C$ than $40^{\circ}C$ thermal exposure. The $CH_4$ emission/kg DMI and organic matter intake (OMI) declined (p<0.05) with increase in exposure temperature and reached its lowest levels at $40^{\circ}C$. It can be concluded from the present study that the digestibility and $CH_4$ emission were affected by intensity of heat stress. Further studies are necessary with respect to ruminal microbial changes to justify the variation in the digestibility and $CH_4$ emission during differential heat stress.

• Elastomers and Composites
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• v.54 no.2
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• pp.110-117
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• 2019

The characterization of the ozone oxidation for raw natural rubber (NR) was investigated under controlled conditions through image and fourier transform infrared (FT-IR) analysis. The ozone oxidation was performed on a transparent thin film of raw NR coated on a KBr window in a dark chamber at $40^{\circ}C$ under low humidity conditions to completely exclude thermal, moisture, or light oxidation. The ozone concentration was set at 40 parts per hundred million (pphm). Before or after exposure to ozone, the image of the thin film for raw NR was observed at a right or tilted angle. FT-IR absorption spectra were measured in the transmission mode according to ozone exposure time. The ozone oxidation of NR was determined by the changes in the absorption peaks at 1736, 1715, 1697, and $833cm^{-1}$, which were assigned to an aldehyde group (-CHO), a ketone group (-COR), an inter-hydrogen bond between carbonyl group (-C=O) from an aldehyde or a ketone and an amide group (-CONH-) of protein, and a cis-methine group ($is-CCH_3=CH-$, respectively. During ozone exposure period, the results indicated that the formation of the carbonyl group of aldehyde or ketone was directly related to the decrement of the double bond of cis-1,4-polyisoprene. Only carbonyl compounds such as aldehydes or ketones seemed to be formed through chain scission by ozone. Long thin cracks with one orientation at regular intervals, which resulted in consecutive chain scission, were observed by image analysis. Therefore, one possible two-step mechanism for the formation of aldehyde and ketone was suggested.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.2
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• pp.263-269
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• 2018

Objective: Heat stress (HS) triggers oxidative stress and respiratory alkalosis in pigs. The objective of this experiment was to study whether a short-term supranutritional amount of dietary vitamin E (VE) can mitigate oxidative stress and respiratory alkalosis in heat-stressed pigs. Methods: A total of 24 pigs were given either a control diet (17 IU/kg VE) or a high VE (200 IU/kg VE; HiVE) diet for 14 d, then exposed to thermoneutral (TN; $20^{\circ}C$, 45% humidity) or HS ($35^{\circ}C$, 35% to 45% humidity, 8 h daily) conditions for 7 d. Respiration rate and rectal temperature were measured three times daily during the thermal exposure. Blood gas variables and oxidative stress markers were studied in blood samples collected on d 7. Results: Although HiVE diet did not affect the elevated rectal temperature or respiration rate observed during HS, it alleviated (all p<0.05 for diet${\times}$temperature) the loss of blood $CO_2$ partial pressure and bicarbonate, as well as the increase in blood pH in the heat-stressed pigs. The HS reduced (p = 0.003) plasma biological antioxidant potential (BAP) and tended to increase (p = 0.067) advanced oxidized protein products (AOPP) in the heat-stressed pigs, suggesting HS triggers oxidative stress. The HiVE diet did not affect plasma BAP or AOPP. Only under TN conditions the HiVE diet reduced the plasma reactive oxygen metabolites (p<0.05 for diet${\times}$temperature). Conclusion: A short-term supplementation with 200 IU/kg VE partially alleviated respiratory alkalosis but did not reduce oxidative stress in heat-stressed pigs.

• Journal of Biosystems Engineering
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• v.39 no.4
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• pp.304-309
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• 2014

Purpose: Weeds cause significant losses in agricultural production. In this study, we investigated the effect of microwaves on the germination rates of cress and arugula seeds to determine whether microwaves could be developed as an effective alternative to conventional chemical-based herbicides. Methods: Seeds were planted at equal depths (8-10 mm) in a soil-turf mixture, and seeds were exposed to microwaves for 126 s, 70 s, and 50 s in a device constructed specifically for this study. A microwave tunnel was built using a variable speed conveyor belt and 4 magnetrons with a combined output power of 2.8 kW. Seeds that were not exposed to microwaves were germinated with regulated irrigation, temperature, and humidity controls in parallel with the treated seeds, and the germination rates were compared among the treatment groups. Results: We found that the exposure of cress and arugula seeds to microwaves for 126 s inhibited germination close to 100%. Cress seeds treated with microwaves for 50 s showed 95% germination compared to 65% germination of the untreated cress seeds. Conclusions: We predict that the thermal effect of microwave energy affects the germination ratio and germination rate of seeds.

• Korean Journal of Rural Living Science
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• v.5 no.1
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• pp.1-8
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• 1994

This study was conducted to examine whether there is any effect of the local body exposure to hot and cold alternate stress on the blood flow and heart rate. Environmental condition was $20^{\circ}C$ air temperature, 65% relative humidity and 0.2m/s air movement. 22~32 years old four healthy female subjects wore clothes which they felt comfort sitting on a chair. And then their left hand was immersed twice in ($42^{\circ}C$\;and\;15^{\circ}C$ water alternately. Two of the subjects (E-group) were continually exposed to above condition 12 times. While, the other two (C-group) were exposed twice only at the 1st and 12th time of E-group's exposure. The results obtained from this experiment were as follows. \circled1 The initial response of the finger blood flow in I-group to the thermal stress showed more sensitively at the post-training than pre-training. \circled2 Heart .ate was higher in hand immersion at hot water ($42^{\circ}C$) than at cold water ($15^{\circ}C$) \circled3 The pattern of the blood flow of the finger and heart rate was different between E-group and C-group.

• Food Science and Biotechnology
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• v.15 no.1
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• pp.5-12
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• 2006

Degradation performance of environmentally friendly plastics that can be disintegrated by combination of sunlight, microbes in soil, and heat produced in landfills was evaluated for use in industries. Two multi-degradable master batches (MCC-101 and MCC-102 were manufactured, separately mixed with polyethylene using film molding machine to produce 0.025 mm thick films, and exposed to sunlight, microbes, and heat. Low- and high-density polyethylene (LDPE and HDPE) films containing MCC-101 and MCC-102 became unfunctional by increasing severe cleavage at the surface and showed high reduction in elongation after 40 days of exposure to ultraviolet light. LDPE and HDPE films showed significant physical degradation after 100 and 120 days, respectively, of incubation at $68{\pm}2^{\circ}C$. SEM images of films cultured in mixed mold spore suspension at $30^{\circ}C$ and 85% humidity for 30 days revealed accelerated biodegradation on film surfaces by the action of microbes. LDPE films containing MCC-l01 showed absorption of carbonyls, photo-sensitive sites, at $1710\;cm${-1}$ when exposed to light for 40 days, whereas those not exposed to ultraviolet light showed no absorption at the same frequency. MCC-101-based LDPE films showed much lower $M_w$ distribution after exposure to UV than its counterpart, due to agents accelerating photo-degradation contained in MCC-101.