• Journal of the Korean Society of Visualization
• /
• v.20 no.3
• /
• pp.117-127
• /
• 2022

The present study has investigated the performance of hydrogen gas generators for inhalation purposes based on polyelectrolyte membrane water electrolysis (PEMWE). The system applied two watering methods. One is pumped water (pumping system) and the other is gravity-fed water without a pump (non-pumping system). The cell efficiencies were compared by measuring the cell voltage and temperature in the hydrogen gas generator, respectively. The results show that the cell voltage and temperature increase with the cell current. The cell temperature is lower in the pumping system than that in the non-pumping system at a given cell current. Even though the amount of hydrogen production is the same regardless of the pumping system, the cell efficiency of the hydrogen gas generator in the non-pumping system is better than that in the pumping system.

• Journal of Environmental Health Sciences
• /
• v.50 no.4
• /
• pp.267-273
• /
• 2024

Background: During the coronavirus pandemic, masks played a critical role in preventing respiratory infections. While the performance of masks such as KF-certified masks and N95 masks was evaluated and managed by the authorities, the performance of common masks was not. Objectives: This study aimed to evaluate the performance of uncertified masks in four Asian countries against certification standards (Korean KF80, KF94, and US N95). Methods: Thirty uncertified mask products from Indonesia, 20 from South Korea, 26 from Taiwan, and 30 from Thailand were purchased to perform performance evaluations. The uncertified masks included disposable dental masks, cloth masks, and children's masks. Filtration efficiency and inhalation airflow resistance tests were conducted according to Korean KF80, KF94, and US N95 protocols. Results: None of the 106 identified masks complied with the KF94 standard. A few complied with the KF80 standard: four from Indonesia, four from South Korea, 13 from Taiwan, and 16 from Thailand. Some of the masks met the N95 standard: one from Indonesia, three from South Korea, two from Taiwan, and one from Thailand. Conclusions: Since many uncertified masks did not comply with performance standards, wearing them might not have provided sufficient protection. Performance of uncertified masks could provide critical information for next pandemic management.

• Korean Journal of Adult Nursing
• /
• v.22 no.1
• /
• pp.31-40
• /
• 2010

Purpose: The purpose of this study was to examine whether there is difference in the effects of aromatherapy on dysmenorrhea by research design. Methods: Findings from the two different research designs (Nonequivalent control group pretest-posttest [NCG] design vs. two-group crossover design) were compared in regard to the effect of aromatherapy on dysmenorrhea. The subjects of the NCG design and the crossover design were a total of 58 female nursing students. The treatments (aroma essential oil inhalation and carrier oil inhalation) were given using a necklace. The data were analyzed by Fisher's exact test, t-test, Mann-Whitney test, paired t-test, and Shapiro-Wilk test using the SPSS/WIN 12.0 program. The effect size for the two research designs was calculated. Results: In both research designs, the level of dysmenorrhea and menstrual pain after the aroma treatment were not significantly different from those after the placebo treatment. The effect size of the NCG design was higher than that of the crossover design. Conclusion: Aroma inhalation may not be effective in managing dysmenorrhea and menstrual pain. In order to further clarify the efficiency of research design and the effect of aromatherapy on discomfort during menstruation, replication studies are necessary. Future studies need to examine the effects of different research design on non-interval variables.

• Horticultural Science & Technology
• /
• v.31 no.2
• /
• pp.239-245
• /
• 2013

Occupational exposure and risk assessment were conducted to evaluate the safety of operators when insecticide acetamiprid was applied to apple orchard using a speed sprayer. Dermal patches, cotton gloves, socks, and masks were used to monitor the dermal exposure, and personal air pump with solid sorbent was used to measure the potential inhalation exposure. In validation to analytical methods, the limit of detection and limit of quantitation were 0.25 ng and 1 ng, respectively. Good reproducibility (coefficient variation < 4%), linearity (coefficient determination > 0.999), and recovery (85.3-118.2%) were obtained. Trapping efficiency of solid sorbent was 96.4% while breakthrough did not occur. Only hand exposure was measured on the gloves during mixing/loading to give $33-1,132{\mu}g$. Exposure amount of operator 3 among 4 workers was noticeably high. The total volumes of spray liquid for operators were $535-1,235mL{\cdot}h^{-1}$, corresponding to 0.03-0.08% of the applied spray solution. Highest contaminated parts of body were thighs, chest, and lower legs. The inhalation exposure ratio to the total application amount was significantly low. However, wind seemed to affect the inhalation exposure of operator. For risk assessment, margin of safety was calculated by the application of cloth and dermal penetration rate to obtain values of much larger than 1 in all cases. Therefore, health risk of operators during treatment of acetamiprid in apple orchard could be of least possibility.

• Korean Journal of Adult Nursing
• /
• v.20 no.6
• /
• pp.941-949
• /
• 2008

Purpose: This study was conducted to describe the effects of aroma inhalation on sleep and fatigue in night shift nurses. Methods: The research design was one group pre-posttest design. The subjects were 17 night shift nurses who work at neurosurgery intensive care unit of K hospital of C university in Seoul. During three consequent night shifts, the participants were worn the Actigraph to measure the sleep pattern on their wrist since their first night shift work. The quality of sleep and fatigue was measured by survey when they awoke at 6 pm after second night shift work. And these measures were repeated during the night shifts in second and third week. Aroma inhalation was applied before going to bed after finishing each night shift work during second and third week. SPSS 12.0 program was used for data analysis. Results: There were no statistically significant differences in sleep latency and total sleeping time. However, significant differences were found in the sleep efficiency, awakening number, sleep quality, subjective symptom and intensity of fatigue. Conclusion: These results showed that aroma inhalation had positive effects on the pattern and quality of sleep and reducing fatigue in night shift nurses.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.16 no.2
• /
• pp.373-379
• /
• 2002

This paper was the design of aerosol generator for inhalation toxicology study of lead and evaluation with real time monitoring, and applied several engineering methodology to classical aerosol generator to cope with it's disadvantages. According to the testing conditions, source temperature 50℃ and inlet-duct band heater temperature 150℃, aerosol generation results for sodium chloride and lead acetate were as followings: CPM(Count Per Minute) for Sodium chloride that used for the testing material in aerosol generation and inhalation system was decreased in the 2nd and the 3rd hour's serial trials, but CVs(coefficient of variation) were maintained within 10%. CPMs for 5 and 2.5 gram of lead acetate that used for aerosol generation and inhalation exposure of lead showed similar results because of the sedimentation of lead acetate on piezoelectric crystal with time. For that reason, heating and mixing of nebulizing solution will be needed to generate lead aerosol with stable profile and maximum generation efficiency. Fluctuations of 10 and 5 gram lead acetate were low but 2.5gram was high. However, CVs for 10, 5, and 2.5gram lead acetate were within 10%. Considering the theoretical efficiencies for sodium chloride and lead acetate, 5gram sodium chloride and 2.5gram lead acetate were appropriate choice. Aerosol generation characteristics for two materials with 1 hour interval were different with respect to the fluctuation of CPM and the decrease to 10gram in it's material. For that reason, sodium chloride can not be used to estimate the aerosol generation and it's related parts for lead acetate. According to the testing conditions, source temperature 20, 50, 70℃, and inlet-duct band heater temperature 20, 50, 100, 150, 200℃, aerosol generation results for sodium chloride and lead acetate were as followings: Excluding inlet-duct band temperature 200℃, maximum CPM for sodium chloride was manifested in source temperature 70℃ with each inlet-duct band temperature conditions. We suggest that this condition was the optimum in the design of aerosol generator, inhalation system, and the testing. Maximum CPMs for 10, 5, and 2.5gram sodium chloride were from source temperature 70℃ and inlet-duct band temperature 20℃. Excluding inlet-duct band temperature 50, 200℃, maximum CPMs for lead acetate were indicated in source temperature 50℃ with each inlet-duct band temperature conditions. We suggest that this condition was the optimum in the design of aerosol generator, inhalation system, and the testing for lead inhalation study. Source and inlet-duct band temperatures for 10, 5, 2.5gram lead acetate were 50 and 100℃, 50 and 100℃, 50 and 150℃, respectively. In conclusion, considering above 2 paragraphs of results for aerosol generation, 5gram efficiencies for sodium chloride, lead acetate were higher than 2.5gram's. If inlet-duct band temperature was same, aerosol generation was increased with increase of source temperature. To get maximum aerosol generation will be the conditions that set the appropriate inlet-duel band temperature for each materials and increase the source temperature.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.19 no.9
• /
• pp.40-46
• /
• 2020

Inspection of vehicle systems is regularly performed by the state to ensure the emission status and the safety of vehicles. Thereby, the safety and quality of life can be improved by reducing green-house gases and fine dust, which are the main causes of vehicle defects and air pollution. This study analyzed the soot measuring probes used in the free acceleration mode method, at no-load condition, looking at the efficiency of a probe to measure soot emissions from diesel vehicles. In this study, a technique that can improve the inhalation efficiency of the probe over the (a) probes and the improved (b) probes was applied to probes (c). Probe (c) involves a structure designed close to the center of the circumference of the exhaust pipe. Results showed that the suction efficiency was improved by adding a variable center unit.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.19 no.1
• /
• pp.29-35
• /
• 2020

Car inspection systems are regularly carried out by the state to ensure the safety and emission status of cars, thereby improving the safety and quality of life by reducing fine dust and greenhouse gases that are the main culprits of vehicle defects and air pollution. These automobile inspections are largely divided into either regular or comprehensive inspections. This study analyzed the smoke measuring probes used in the lug - down 3 mode. In the previously issued paper "Improvement of Soot Probe Efficiency for Automotive Emission Measurement," an improved smoke measurement probe(B) improved on the problems that arise from the current smoke measurement probe (A). In this study, a technique that can improve the probe's inhalation efficiency over the improved (B) probes was applied to probes (C). Probe (C) involves a structure designed close to the center of the circumference of the exhaust pipe, and the suction efficiency was improved by adding a variable center unit.

• The Korean Journal of Pesticide Science
• /
• v.19 no.3
• /
• pp.230-240
• /
• 2015

An IOM sampler equipped with glass fiber filter has been recently utilized instead of solid adsorbent, which was used to measure the inhalation exposure of agricultural operator to pesticides. The aim of this study is to validate the efficacy of an IOM sampler by measuring the trapping efficiency and breakthrough using kresoxim-methyl water-dispersible granule and fenthion emulsifiable concentrate. On LC-MS/ MS, minimum detection level was 12.5 pg and method limit of detection was 5.0 ng/mL. Good linearity ($R^2$ > 0.999) for matrix matched standards was obtained. Recoveries of pesticides from glass fiber filter were 102-109% (kresoxim-methyl) and 97-104% (fenthion) while those from XAD-2 resin were 94-98% (kresoxim methyl) and 93-100% (fenthion). Trapping efficiency test was performed with personal air pumps and IOM sampler (glass fiber filter) connected with solid adsorbent (XAD-2 resin) with two types of formulation (solid and liquid) which were diluted by standard rate and sprayed to IOM sampler. Those pesticides were trapped only in glass fiber filter without any breakthrough to solid adsorbent. After spiking of pesticides to glass fiber filter, breakthrough test was carried out with IOM sampler (glass fiber filter) which was connected with solid adsorbent. As a results, 87-101% of kresoxim-methyl and 96-105% of fenthion remained in spiked glass fiber filter, however, no pesticides were detected in second glass fiber filter and solid adsorbent. In conclusion, IOM sampler which equipped with glass fiber filter can be applied widely for pesticide inhalation exposure study since it has good trapping efficiency and adsorption capacity, regardless of the solid or liquid formulation.

• Journal of Preventive Medicine and Public Health
• /
• v.54 no.1
• /
• pp.31-36
• /
• 2021

Objectives: Non-traditional materials are used for mask construction to address personal protective equipment shortages during the coronavirus disease 2019 (COVID-19) pandemic. Reusable masks made from surgical sterilization wrap represent such an innovative approach with social media frequently referring to them as "N95 alternatives." This material was tested for particle filtration efficiency and breathability to clarify what role they might have in infection prevention and control. Methods: A heavyweight, double layer sterilization wrap was tested when new and after 2, 4, 6, and 10 autoclave sterilizing cycles and compared with an approved N95 respirator and a surgical mask via testing procedures using a sodium chloride aerosol for N95 efficiency testing similar to 42 CFR 84.181. Pressure testing to indicate breathability was also conducted. Results: The particle filtration efficiency for the sterilization wrap ranged between 58% to 66%, with similar performance when new and after sterilizing cycles. The N95 respirator and surgical mask performed at 95% and 68% respectively. Pressure drops for the sterilization wrap, N95 and surgical mask were 10.4 mmH2O, 5.9 mmH2O, and 5.1 mmH2O, respectively, well below the National Institute for Occupational Safety and Health limits of 35 mmH2O during initial inhalation and 25 mmH2O during initial exhalation. Conclusions: The sterilization wrap's particle filtration efficiency is much lower than a N95 respirator, but falls within the range of a surgical mask, with acceptable breathability. Performance testing of non-traditional mask materials is crucial to determine potential protection efficacy and for correcting misinterpretation propagated through popular media.