• 한국축산식품학회지
• /
• 제39권4호
• /
• pp.668-676
• /
• 2019

This study aimed to investigate the effect of an electric field refrigeration (EFR) on the quality characteristics of pork loin including dry aging loss, pH, water holding capacity (WHC), cooking loss, color, shear force, thiobarbituric acid reactive substances (TBARS), and microbial growth during dry aging (0, 1, 2, 3, 4, 7, and 9 wk) in comparison with a commercial refrigerator (CR). Total plate counts (TPC) of the CR group approached 8.07 Log CFU/g at 2 wk of dry aging, thus indicating meat spoilage. Cooking loss, lightness, and shear force of EFR were significantly decreased (p<0.05) at subsequent aging weeks in both the EFR and CR. Aging loss, TPC, TBARS levels increased at subsequent aging weeks; however, pH values were not influenced by aging. At the same aging weeks (1 or 2 wk), the EFR group displayed significantly lower values (p<0.05) of aging loss, pH, TPC, and TBARS levels than the CR group. No significant differences in WHC, cooking loss, and shear force was observed until 2 wk of aging between the EFR and CR groups. The present results show that application of the EFR system improves the tenderness, color, and lipid oxidation stability of pork loin and extends its shelf life in comparison with a commercial refrigeration.

• 한국축산식품학회지
• /
• 제40권2호
• /
• pp.286-296
• /
• 2020

This study investigates the utilization of an electric-field-induced super cooling system in long-term dry aging of beef loin. Analyzed quality properties of dry-aged beef loin applied with electric field refrigeration (EFR) versus commercial refrigeration (CR). Quality properties was including aging loss, pH, water holding capacity (WHC), cooking loss, color, warner-bractzler shear force (WBSF), total plate count (TPC), and thiobarbituric acid reactive substances (TBARS). Aging loss of wk 1 EFR was significantly lower than CR (p<0.05). pH of EFR was slow change tendency compared CR. WHC of both aging methods were higher with increase in aging duration. Cooking loss of wk 1, 2, 4, and 10 EFR were significantly lower than CR (p<0.05). Lightness and redness of EFR was slow change tendency compared CR. However, yellowness of EFR was increased until wk 2, 3, and significantly decreased at wk 10 (p<0.05), but yellowness of CR was decreased until wk 3 and significantly increased with an increasing aging weeks (p<0.05). Both aging methods of WBSF was decreased with increase in aging weeks; however, wk 10 of CR was significantly lower than EFR (p<0.05). TPC after wk 3 EFR groups were significantly lower than CR groups (p<0.05), and TBARS of EFR groups were significantly lower than CR (p<0.05). The present results show that application of the EFR system for dry aging beef loin can extends its shelf life and induce changes of several aging properties in similar to commercial aging.

• 전기의세계
• /
• 제28권5호
• /
• pp.39-43
• /
• 1979

The aging of permittivity of a barium titanate dielectrics doped with La$_{2}$O$_{3}$ under zero and low DC field has been studied. The aging rate was decreased as the amount of La$_{2}$O$_{3}$ addition is increased to 3 mole%. The zero field aging rate of barium titahate doped with La$_{2}$O$_{3}$. 3TiO$_{2}$ was similar to that doped with La$_{2}$O$_{3}$.5V/mil DC field aging rate of La$_{2}$O$_{3}$.3TiO$_{2}$ doped sample, howeve, was lowered to that of La$_{2}$O$_{3}$ doped sample. When the phase transformation is occured from the paraelectric state to the ferroelectric state, 90.deg. domains are mucleated in order that the system becomes thermodynamically more stable. It is concluded that the aging phenomenon is occured as the dielectric constant is decreasing by the nucleation and growth of 90.deg. domains.

• 한국세라믹학회지
• /
• 제24권5호
• /
• pp.477-483
• /
• 1987

Cr2O3 doped Pb(Zr0.525 Ti0.475)O3 piezoelectric ceramics were prepared from reagent grade oxide mixture, PbO, ZrO2, TiO2 and Cr2O3. Piezoelectric and aging properties of specimens were measured for various additions of Cr2O3. Generally, it has been known that aging rate decreased with Cr2O3 addition by stabilizing the domain wall. But hysteresis loops showed that the domain destabilization was occurred at high electric field (larger than 10KV/cm). In smaller additions of Cr2O3 (0-0.2mol%), aging rate increased and microcracks were created with increasing poling filed due to increasing internal stress. In larger additions of Cr2O3(0.4∼0.6mol%), aging rate decreased with increasing poling field.

• 대한전기학회논문지:전기물성ㆍ응용부문C
• /
• 제51권2호
• /
• pp.62-67
• /
• 2002

This paper provides the results of accelerated aging test of 18kV ZnO lightning arresters to investigate the leakage current characteristics. It was impossible to establish the replacement criterion for field operating lightning arrester because conventional aging test was only focused on the aging of ZnO elements. In general, it is possible to replace the aged arresters before the failure in the field using the leakage current measurement because it must be increased by the aging. But we can not use the method because we don't know the characteristics of the installed lightning arresters. Therefore in this paper we applied operating voltage and accelerating cycle which consists of temperature and humidity to the arresters. Then we measured the variation of total and resistive leakage current and found out the characteristics of the acted lightning arresters.

• 한국세라믹학회지
• /
• 제46권2호
• /
• pp.219-223
• /
• 2009

Effects of MgO or $R_2O_3$(R:Dy, Ho, Yb) on the capacitance aging behavior of multilayer ceramic capacitors (MLCCs) based on $BaTiO_3$ dielectrics under DC electrical fields has been studied. At a DC field of 1 $V{/\mu}m$, the capacitance of MLCC specimens dropped immediately in a very short period (<10 s, the first stage) and then decreased continuously with time (the second stage). Mn doping significantly increased the aging rate in the second stage. The addition of MgO or $R_2O_3$ notably decreased the second stage aging rate of Mn-doped specimens. Yb doping gives rise to the lowest aging rate in the second stage, which is due to the larger population of defect dipoles associated with oxygen vacancies.

• 한국전기전자재료학회논문지
• /
• 제13권10호
• /
• pp.847-858
• /
• 2000

The aging characteristics of 2 kinds of 3 years field-aged distribution polymer insulators which were dismounted from 5 regions have been investigated by electrical test and material characterization. Although the tan $\delta$of specimens prepared from weathershed was increased with surface aging, the tan $\delta$and leakage current of real products had no difference between virgin and dismounted ones. Due to the aging, all dismounted polymer insulators had micro-cracks on the surface of weathershed and only the products of manufacturer B showed the reduction of OIT(oxidation induction time). But, there were no differences between virgin and dismounted products in contact angle and chemical structure. Therefore, it can be considered that the aging is only limited on the surface of dismounted polymer insulators and that NMR technique are very useful to evaluate the aging of polymer materials.

• Journal of Acupuncture Research
• /
• 제18권1호
• /
• pp.146-156
• /
• 2001

Objectrve : To research the trends of the study related to aging process, and to establish the direction of the study on aging process. Method : We reviewed the journal and essay about the aging process which are published as well in Korea as in foreign country. Results : 1. The study on the Oriental Medicine field can be classfied with the fourth. first, the study of single herb medication's effect on the aging process. second, the study of multiple herb medication's effect on the aging process. third, the study of herb-acupuncture solution's effect on the aging process. fourth, journal review. We find the fact that the study on the Oriental Medicine is concerned with pathology of deficiency syndrome of the kidneys, retention of phlegm and fluid, blood stasis. 2. On the Western Medicine field, mechanism and pathology of aging pracess primarily has been studied. The mechanism of aging process is classified with 'Wear and tear theory' and 'Genome-based theory'. Among the mechanism of aging process, 'Free radical theory' is the most important. Additionally 'Senescence-Accelerated Mouse' has been studied. 3. We review the journal published in foreign country and its subject was the following: first, moxibustion combined with acu-area skin allograft therapy for the aging was effective, second, the traditional chinese medicine bu-zhong-yi-qi-tang in mice have anti-aging effect. third, the overview Preventive geriatrics of Traditional chinese medicine. 4. We researched anti-aging effect study in the journal of the Korean Acupuncture and Moxibustion, and we found a few journal of Herb-acupuncture solution's anti-aging effect. Hereafter, it is necessory that we will study about relationship between acupuncture-moxibustion therpy and anti-aging effect using Senescence-Accelerated Mouse.

• KIEAE Journal
• /
• 제12권4호
• /
• pp.47-57
• /
• 2012

The purpose of this study is to develop an aging friendly guideline aging friendly outdoor exercise environment in Universal design aspect. The aim for this guideline is to suggest a creative method to cope with forthcoming aging society and meet the various demands of all park users. Documentary survey and field survey were used to extract notion of universal design and aging friendly design; based from the extracted notions three types of exercise environment were suggested, Small scale, Medium scale and Large scale. The significant of this guideline is as fallow: First, negative aspects of aging friendly design can be eliminated by adopting universal design; therefore the guideline can have social integration aspect. Second, reflected needs of residents can be suggested on the guideline; and it was extracted from documentary survey, PPP UD checklist and field survey. Third, classifying universal design and aging friendly design in one guideline can enhance ability to manage various composition of population. Fourth, by studying young child and old people's likeness and parallel resemblance, design guideline for forthcoming aging society can be suggested. Fifth, from three developed exercise environments, the guideline can be applied into different conditions of location. Sixth, canopy type design model can be very useful for old people.

• 한국도로학회논문집
• /
• 제18권3호
• /
• pp.1-9
• /
• 2016

PURPOSES : This study aims to show the difference of the binder aging level in the hot-mix asphalt (HMA) mixture after short-term aging (SA) under different aging conditions, such as mixture temperature and duration in hour. METHODS : Three SA times (i.e., 1 h, 2 h, and 4 h) at two temperatures (i.e., $160^{\circ}C$ and $180^{\circ}C$) were used for the normal mixtures prepared using a PG64-22 asphalt. The field long-term aging (LA) was simulated by applying the same LA procedure (65 h at $110^{\circ}C$) to all compacted specimens, prepared at the air void of 7% using each SA-treated mixture, in a convection oven. The binder aging level was measured in terms of large molecular size by gel-permeation chromatography (GPC) from the mixture and the absolute viscosity (AV) from the recovered binder. The aging levels were evaluated using those two properties after SA and LA, and then compared based on the normal SA (NSA) mixture (1 h at $160^{\circ}C$). The service life reduction caused by SA in various conditions was estimated based on the aging level of the field cores from different locations in various service lives. RESULTS : The results of the laboratory evaluation indicated that the binder of the mixture, which was treated at longer SA time and higher temperature, showed a significantly higher aging level than the NSA mixture. The binder aging level from a longer time, such as 2 h and 4 h SA, or at a higher temperature ($180^{\circ}C$), were estimated to be similar to that of the mixtures, which had already been in field service for several years. CONCLUSIONS : The HMA mixture should be produced at a moderate temperature, such as $160^{\circ}C$, and placed within a limited hauling and queuing time to avoid a significant short-term aging of the binder before placement in the field pavement. The SA for a longer time at a higher temperature than the NSA condition was found to be detrimental to the service life of the asphalt pavement.