• The korean journal of orthodontics
• /
• v.28 no.6 s.71
• /
• pp.927-935
• /
• 1998

The purpose of this study is to investigate the changes of mechanical properties and surface topography of various nickel titanium wires after heat sterilization for recycling with quantitative method. The materials used were four kinds of nickel titanium orthodontic wires including a Korean product. Experimental specimens were treated with two kinds of heat sterilization methods ; dry heat ($180^{\circ}C$, 60min) and autoclave ($121^{\circ}C$, 15-20psi, 30min). Mechanical properties were evaluated by tensile test with Instron 4466 (load cell capacity:.1000 kg, cross head speed:5mm/min, grip distince:40mm in room temperature). Surface topography of various wires was compared with each other qualitatively by using scanning electron microscopy and quantitatively by using profilometer. The findings were analyzed statistically with student t-tests. The results were as follows; 1. Neither method of heat sterilization had any effects on tensile properties of the nickel-titanium wires used in this experiment. 2. Before heat sterilization, the surface smoothness was highest in Optimalloy, followed by Align and Sentalloy, with NiTi showing the lowest smoothness value. 3. In surface topography, Align and Optimalloy were not influenced by heat sterilization. NiTi, on the other hand, had increased roughness after dry heat sterilization and Sentalloy showed the same tendency after each of the two heat sterilization procedures.

• Journal of Life Science
• /
• v.12 no.5
• /
• pp.589-594
• /
• 2002

Changes in the content of volatile terpenoids were investigated with heat-treated carrot. As heat treatment temperature became higher, the amount of volatile terpenoids decreased significantly. According to heat-treatment period, the volatile terpenoids, a-pinene and total terpenoids, decreased drastically during the initial 30-minutes of heat treatment but the rate of decrease slowed down afterwards. When changes in the content of volatile terpenoids in carrot juice were investigated according to sterilization temperature and period, the content decreased quickly with higher sterilization temperature. According to sterilization period, the content of volatile terpenoids decreased drastically during the initial 20-minutes of sterilization but decreased gradually afterwards. The amount of total terpenoids decreased more when sterilization was done at 10$0^{\circ}C$ for 20 minutes compared to sterilization at 6$0^{\circ}C$ and 8$0^{\circ}C$ for 60 min. In order to reduce the amount of volatile terpenoids in carrot juice, sterilization at high temperature for a short period of time would be more effective compared with sterilization at low temperature for a long period of time.

• Restorative Dentistry and Endodontics
• /
• v.45 no.2
• /
• pp.25.1-25.12
• /
• 2020

Objectives: This systematic review evaluated the influence of autoclave sterilization procedures on the cyclic fatigue resistance of heat-treated nickel-titanium (NiTi) instruments. Materials and Methods: A systematic search without restrictions was conducted in the following electronic databases: PubMed, Scopus, Web of Science, ScienceDirect, Cochrane, and Open Grey. The hand search was also performed in the main endodontic journals. The eligible studies were submitted to the methodological assessment and data extraction. Results: From 203 abstracts, a total of 10 articles matched the eligible criteria. After reading the full articles, 2 were excluded because of the absence of the heat-treated instruments in the experimental design and 3 due to the lack of a control group using heat-treated instruments without autoclave sterilization. From the 5 included studies, 1 presented a low risk of bias, 3 presented moderate and 1 high risk. It was observed heterogeneous findings in the included studies, with autoclave sterilization cycles increasing, decreasing or not affecting the cyclic fatigue life of heat-treated NiTi instruments. However, the retrieved studies evaluating the cyclic fatigue resistance of endodontic instruments presented different protocols and assessing outcomes, this variability makes the findings less comparable within and also between groups and preclude the establishment of an unbiased scientific evidence base. Conclusions: Considering the little scientific evidence and considerable risk of bias, it is still possible to conclude that autoclave sterilization procedures appear to influence the cyclic fatigue resistance of heat-treated NiTi instruments.

• The Korean Journal of Food And Nutrition
• /
• v.35 no.5
• /
• pp.343-352
• /
• 2022

Low alcohol (6%) wines were manufactured using Campbell Early. To develop the sterilization process of low alcohol wines, red wines were heat sterilized, and rose wines were nonthermal sterilized by concentration using potassium metasulfite and potassium sorbate. Samples were stored at 25℃ and quality characteristics were investigated by period. Results of this study revealed the pH of the samples after sterilization ranged from 3.15 to 3.19, and the total acidity of wines ranged from 0.011 to 0.024%. The free SO₂ contents of wines ranged from 13.00 to 29.678 mg/L, and the total SO₂ contents of wines ranged from 47.50 to 121.00 mg/L. L (lightness) of wines decreased whereas a (redness) and b(yellowness) increased. The hue value of wines ranged from 0.52 to 1.03, and decreased significantly(not including rose sweet wines). The color intensity of red and rose dry wines after sterilization increased, whereas red and rose sweet wines decreased. The DPPH radical scavenging activity of red wines and rose wines ranged between 75.50 to 89.23%, and 36.60 to 56.54%, respectively. The total polyphenol contents were 57.51~182.63 mg%. Results of this study provide scientific information to establish the sterilization process of low alcohol wines.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.39 no.1
• /
• pp.39-44
• /
• 2019

The effect of heat treatment on the sterilization and fatty acid compositions of silkworm powder was carried out under the guidance of Ministry of Food and Drug Safety. Food borne pathogens or microorganisms including E. coli, Salmonella spp., Listeria monocytogenes, Staphylococus aureus, Clostridium perfringens and aflatoxin, were not detected. The fatty acid composition was hardly changed after the silkworm powder was treated to a high temperature of $121^{\circ}C$. The low temperature sterilization of silkworm powder at $63^{\circ}C$ decreased the concentration of E. coli while high temperature sterilization at $121^{\circ}C$ has found no traces of microorganism.

• Journal of the Korean Applied Science and Technology
• /
• v.28 no.1
• /
• pp.29-34
• /
• 2011

The sterilization of strain and algae in sea water was studied to see the possibility to apply the redox reaction of metal alloy to meet the international marine organization(IMO) regulation, which was to regulate deballasting concentration of strain and algae above 99% of sterilization. Two different kinds of brass were heat treated at different temperature and cooled rapidly to conserve the specific character of ${\beta}$ brass. Untreated Muntz metal showed the best result of antimicrobial rate in sea water, and 7:3 brass showed similar result to Muntz metal. Heavy metal elution rate was inversely proportional to the sterilization capability.

• The Korean Journal of Food And Nutrition
• /
• v.36 no.4
• /
• pp.334-339
• /
• 2023

To suppress mold generation of yujacheong, Penicillium chrysogenum LB31 was cultured, and spores were harvested and put into yujacheong. Antioxidant activity, useful ingredients, mold size and incidence were investigated while storing yujacheong for 30 days, after sterilization with different methods (nontreatment, ozone gas emission, heating after ozone gas emission and heating). The results showed that the content of narirutin, naringin, hesperidin, or neohesperidin, which are functional components of yuzu, increased as the storage period increased in all the treatment units. In addition, mold generation was not observed until the 15th day in the heat treatment group after ozone gas emission. As the treatment group emitted ozone gas. molds of 34.8 and 112 mm2 in size were observed on the 30th day. These results suggested that ozone sterilization can prevent microbial contamination, further extending the shelf life of yuzacheong and maintaining a fresh state.

• Culinary science and hospitality research
• /
• v.20 no.6
• /
• pp.254-261
• /
• 2014

In order to optimize process conditions for manufacturing retorted Kimchi soup by using stationary and rotary types systems were applied for sterilization process. For investigating the differences in heat penetration characteristics during sterilization, Kimchi soup was packed into retort pouches, and sterility ($F_0$ value) at various positions in the product was measured through a wireless $F_0$ sensor. Heat penetration characteristics were significantly affected by sterilization method. From data analysis, optimum ranges of sterilization temperature and time was determined to be $120.7^{\circ}C$, 13 min for rotary type and $120.7^{\circ}C$, 20 min for stationary type. At those conditions, they had similar sterility ($F_0$ value). The results showed that rotation provides faster heat penetration and more uniform sterility than various positions of the product. These results derived a lot of advantages from related industry. For instance, many of the more viscous semi-liquid products and heat sensitive natural products could be sterilized in the lager pouch sizes without overcooking or scorching. Hence, current study suggests that rotary type retort would make it possible not only to reduce processing times as 35~45%, but also to improve the quality of product as overall taste, flavor, color, and texture with significant difference (p<0.05).

• Journal of Biosystems Engineering
• /
• v.35 no.2
• /
• pp.108-115
• /
• 2010

This study was conducted to estimate the optimum temperature and required time for soil sterilization when heated water was circulated through underground heating pipes in the greenhouse which solar heat was influenced to the temperature of soil during the summer day. Two different types of heating pipes were used for the experiment. One was a polyethylene pipe(XL) and the other was a corrugated ring shaped stainless steel pipe(STS). The results of the studies were summarized as follows; By measuring the thermal characteristics of the XL and STS, it was examined that the average temperature differences of the inlet and outlet were $8.5^{\circ}C$ and $13.3^{\circ}C$, the average flowrates were 15.3 L/min and 5.6 L/min, and the average radiation powers were 9.1 kW and 4.1 kW, respectively. As results of the regression analysis of underground temperatures, when average soil temperature was$35^{\circ}C$, an average water temperature was $80^{\circ}C$, and XL was used, it was estimated that the possible heat transfer distance, the required time for heat transfer and heat flux to reach the underground temperature of $60^{\circ}C$ were 300 mm, 230 hours, and $7.57kW/m^2$, respectively.

• Journal of Environmental Health Sciences
• /
• v.8 no.1
• /
• pp.81-97
• /
• 1982

Ethylene oxide gas has been used as a cold sterilant for heat-sensitive medical equipments and as a fumigant for food for more than 30 years, and it is used more widely than radiation although radiation sterilization has made significant inroads in recent years. But according to recent studies of toxicities such as mutagenicity, haemolytic effect and possible carcinogenicity of Ethylene oxide (ETO) and its two main reaction products, Ethylene chlorohydrin (ETCH) and Ethylene glycol (ETG), Environmental Protection Agency in U.S.A. has suggested some regulations on residual gas in drug products and medical devices for human use. The mutagenic activity of ETO compared with that of X-ray has an equivalency of 1 ppm/hr for ETO as compared to 20 mrad for X-ray, and one could suggest the present maximum allowable concentration for ETO (50 ppm) should be 400 times lower than the radiation standard (2.5 mrad/hr). Although radiation sterilization has advantages of simplicity of operation and complete reliability, changes of physico-chemical properties with possible formation of toxic substances may occur. It is therefore necessary to make some regulations of our own for residual toxicities orginated from each sterilization method.