염지 온도와 기간이 삶은 돼지고기 등심의 이화학적 특성과 기호성에 미치는 영향

현재석,강희곤,김미숙,정인철,문윤희 한국축산식품학회 2003 한국축산식품학회지 Vol.23 No.1

식염농도 7%의 염지액을 이용하여 돼지고기 등심을 염지할 때에 염지온도와 기간이 염지육의 이화학적 특성과 기호성에 미치는 영향을 검토하였다. 열지온도 1$0^{\circ}C$에서 15일째에 염지육의 pH와 보수력이 현저히 저하되었다. 염지온도 1$0^{\circ}C$에서 염지액과 염지육 표면부위의 일반세균수는 12째에 현저히 많아졌으나 중심부위는 거의 검출되지 않았다. 임시 온도가 높을수록 염지기간에 관계없이 식염 침투가 빠르고 염지육 식염함량이 많아졌으며, 표면부위에 대한 중심분위의 식염함량 비율은 염지기간이 길수록 크게 나타났다. 염지육의 식염함량은 가열에 의하여 적어졌다. 염지 가열육의 짠맛과 풍미는 염지 초기에는 높은 온도에서, 후기에는 낮은 온도에서 우수하였다. 열지 가열육은 1$^{\circ}C$에서 12일, 5$^{\circ}C$에서 9일 염지하여 제조하면 기호성이 우수하였다. The effects of curing temperatures(1, 5 and 10$^{\circ}C$) and times on the chemical properties and palatability of cured pork loins which were cured in the 7% curing solution were investigated. The pork loins cured at 10$^{\circ}C$ curing temperature showed the decreased level of pH and water holding capacity up to 15 days of curing time. The growth of bacteria in the curing solution and surface region of cured loins, cured at 10$^{\circ}C$ were rapid after 12 days of curing. However, bacteria were not detected(<0.05${\times}$10$^2$ CFU/g) in the central region of cured loin until 15 days of curing. The penetration of salt into the central region of cured loins was faster at 10$^{\circ}C$ curing temperature than at lower curing temperatures for all curing times. The difference of salt contents between surface and central regions in the cured loins was less at higher temperature than at lower temperatures, and the difference decreased in boiling process for all curing times. The color fixation of the cured boiled loins was better at 5 and 10$^{\circ}C$ curing temperatures than at 1$^{\circ}C$. The sensory scores for saltiness and flavor of the cured boiled pork loins were higher at higher temperature than at lower temperatures until 9∼12 days of curing. Palatable cured boiled pork loins could be produced under the curing solution at low temperatures of 1 and 5$^{\circ}C$ for 12 and 9 days, respectively.

Effects of subsequent curing on chloride resistance and microstructure of steam-cured mortar

Hu, Yuquan,Hu, Shaowei,Yang, Bokai,Wang, Siyao Techno-Press 2020 Advances in concrete construction Vol.9 No.5

The influence of subsequent curing on the performance of fly ash contained mortar under steam curing was studied. Mortar samples incorporated with different content (0%, 20%, 50% and 70%) of Class F fly ash under five typical subsequent curing conditions, including standard curing (ZS), water curing(ZW) under 25℃, oven-dry curing (ZD) under 60℃, frozen curing (ZF) under -10℃, and nature curing (ZN) exposed to outdoor environment were implemented. The unsteady chloride diffusion coefficient was measured by rapid chloride migration test (RCM) to analyze the influence of subsequent curing condition on the resistance to chloride penetration of fly ash contained mortar under steam curing. The compressive strength was measured to analyze the mechanical properties. Furthermore, the open porosity, mercury intrusion porosimetry (MIP), x-ray diffraction (XRD) and thermogravimetric analysis (TGA) were examined to investigate the pore characteristics and phase composition of mortar. The results indicate that the resistance to chloride ingress and compressive strength of steam-cured mortar decline with the increase of fly ash incorporated, regardless of the subsequent curing condition. Compared to ZS, ZD and ZF lead to poor resistance to chloride penetration, while ZW and ZN show better performance. Interestingly, under different fly ash contents, the declining order of compressive strength remains ZS>ZW>ZN>ZD>ZF. When the fly ash content is blow 50%, the open porosity grows with increase of fly ash, regardless of the curing conditions are diverse. However, if the replacement amount of fly ash exceeds a certain high proportion (70%), the value of open porosity tends to decrease. Moreover, the main phase composition of the mortar hydration products is similar under different curing conditions, but the declining order of the C-S-H gels and ettringite content is ZS>ZD>ZF. The addition of fly ash could increase the amount of harmless pores at early age.

Effect of Steam Curing on Concrete Piles with Silica Fume

N. Yazdani,F. ASCE, M. Filsaime,T. Manzur 한국콘크리트학회 2010 International Journal of Concrete Structures and M Vol.4 No.1

Silica fume is a common addition to high performance concrete mix designs. The use of silica fume in concrete leads to increased water demand. For this reason, Florida Department of Transportation (FDOT) allows only a 72-hour continuous moist cure process for concrete containing silica fume. Accelerated curing has been shown to be effective in producing high-performance characteristics at early ages in silica-fume concrete. However, the heat greatly increases the moisture loss from exposed surfaces, which may cause shrinkage problems. An experimental study was undertaken to determine the feasibility of steam curing of FDOT concrete with silica fume in order to reduce precast turnaround time. Various steam curing durations were utilized with full-scale precast prestressed pile specimens. The concrete compressive strength and shrinkage were determined for various durations of steam curing. Results indicate that steam cured silica fume concrete met all FDOT requirements for the 12, 18 and 24 hours of curing periods. No shrinkage cracking was observed in any samples up to one year age. It was recommended that FDOT allow the 12 hour steam curing for concrete with silica fume.

이중경화법을 이용한 열개시제 및 광개시제가 배합된 황칠도료의 경화속도 촉진 및 물성향상 연구

황현득 ( Hyeon Deuk Hwang ),문제익 ( Je Ik Moon ),박초희 ( Cho Hee Park ),김현중 ( Hyun Joong Kim ),황백 ( Baik Hwang ) 한국목재공학회 2010 목재공학 Vol.38 No.4

한반도 남부 일대에서 자생하는 황칠나무(Dendropanax morbifera Lev.) 수액으로부터 추출한 천연 도료인 황칠도료(Korean Dendropanax lacquer)는 예로부터 귀중한 예술품이나 투구, 화살, 활 등의 전쟁도구를 찬란한 황금색으로 도장하는데 사용되어 왔다. 경화 후 황금색의 투명한 도막을 형성하여 우수한 색상특성을 지니고 있을 뿐만 아니라 내후성, 내수성, 내식성 등이 우수하여, 보호도장으로써도 훌륭한 가치를 지니고 있다. 그러나 이러한 많은 장점에도 불구하고, 현대적인 여러 적용분야에 사용되지 못하고 있는 이유는 황칠도료의 생산량이 적고, 이로 인하여 가격이 매우 고가이고, 장시간의 경화시간이 소요되는 문제도 큰 원인으로 작용하고 있다. 한편 황칠 내에 광중합이 가능한 conjugated diene을 포함한 모노머가 있으며, 이러한 모노머는 일광 조사 조건 등에 의하여 짧은 시간에 단단하고 황금색을 띠는 도막을 형성할 수 있음이 보고된 바가 있다. 따라서 본 연구에서는 전통적인 황칠도료의 경화방법을 개선하고 경화속도를 촉진하기 위하여, 열개시제를 도입하여 열경화를 촉진하는 방법과 열개시제 및 광개시제를 동시에 도입하고 이중경화(dual curing)에 의해서 경화속도를 촉진하고자 하였다. 이러한 경화 속도 및 경화 거동은 적외선분광분석기(FT-IR)을 이용하여 -C=C- 이중결합 특성피크의 변화를 관찰하거나, 진자경도계(pendulum hardness tester)를 이용하여 표면 경도의 변화를 관찰함으로써 평가하였다. 또한 강체진자물성측정기(RPT)에 spot UV curing 장비를 도입하여 이중경화에 의한 경화 속도 촉진을 평가하였다. 본 연구의 결과 열개시제에 의하여 열경화가 촉진될 수 있을 뿐만 아니라, 이중경화에 의하여 경화속도를 향상시킬 수 있음을 확인하였다. 또한 이러한 황칠도료 경화 속도 촉진 방법을 활용하여 전통적인 영역에만 사용되어온 황칠도료를 현대적인 여러 적용분야에도 확대하여 사용할 수 있는 가능성을 제시하였다. The Korean Dendropanax lacquer, made from a natural resinous sap from Dendropanax morbifera Lev., was used as a golden and transparent varnish for the traditional artifacts (armor suits, helmets, arrowheads, etc.) to make them be brilliant golden color. The cured film of the lacquer has excellent protective properties such as weatherability, water resistance, and anticorrosive. But, one of disadvantages is that takes a long time and much energy to fulfill curing of the lacquer. The chemical constituents of the lacquer contained conjugated diene compounds as the photopolymerizable monomers. These monomers easily polymerized in sunlight to form golden-colored, hard-coating films in a short time. Photooxidation may be one of the most important reactions in the chemistry of the lacquer. Although the Korean Dendropanax Lacquer should be dried to a thoroughly dry stage to achieve optimal film properties, curing with elevated temperatures may be required for the protracted curing time at atmospheric temperature. So we intended to accelerate the curing rate of the lacquer by dual curing of thermal and radiation curing. The effect of thermal initiator on the thermal curing reaction was evaluated by monitoring the changes in double bond peak with FT-IR. Then the curing rate of the lacquer blended with thermal initiator and photoinitiator together was measured during dual curing using a RPT with UV spot curing machine. Thermal initiator not only accelerated the curing rate but also improved the physical property. And the curing rate of the Korean Dendropanax lacquer was improved by dual curing method of thermal and UV curing. According to these results, the application area of the Korean Dendropanax lacquer could be expanded to surface coatings for electronic devices such as mobile phones or electronics.

버어리종 잎담배 건조 환경 개선을 위한 건조실 개발 (I. 건조기간중의 미기상 변화)

차광호,장수원,양진철,오경환,신승구,조천준,Cha, Kwang-Ho,Jang, Soo-Won,Yang, Jin-Chul,Oh, Kyoung-Hwan,Shin, Seung-Ku,Jo, Chun-Joon 한국연초학회 2007 한국연초학회지 Vol.29 No.2

This study was carried out to investigate the changes of curing condition on microclimate of temperature, relative humidity during curing process of burley tobacco leaves. The developed facility, ridge opening type was designed to open the central top roof. The air-cured variety, (N. tabacum cv KB111) was normally grown at the Eumseong tobacco experimental station in 2007. Mean daily temperature of $3^{\circ}C$ in ridge opening type curing facility was lower than that of conventional, whereas mean daily relative humidity of 12.6 % RH was lower in conventional curing facility for the entire stage of curing. The frequency distribution of optimal air temperature at daytime was higher 37.5 % in ridge opening type curing facility than that of conventional, while that of optimal relative humidity was lower 8.2 %. In the ridge opening type curing facility, the excessive drying leaves were low, however the price per kilogram was high. These results suggest that the new developed curing facility may be applied to improved microclimate inside the curing facility for curing burley.

버어리종 건조방법이 건엽의 품질에 미치는 영향

배성국,조천준,임해건,김요태 한국연초학회 1998 한국연초학회지 Vol.20 No.1

This study was conducted to obtain the basic information on the burley tobacco (Nicotiana tabacum L.) curing methods. The effects of the three kinds of curing methods on the dry weight losses during curing, chemical contents and physical properties of cured leaves, and organoleptic and smoking qualities were observed. The dry weight losses during curing was the highest in the stalk curing, and the lowest in the conventional priming. The longer the curing periods was, the more the loss of dry weight. The percent of the excessive dried leaves was high and the price per kilogram was low in the conventional priming. The chemical contents and the physical properties of the cured leaves in the conventional priming were similar to those of yellowing or browning stage of curing. But, the chemical contents and the physical properties of the cured leaves in the stalk curing were comparable to those of the air curing. The smoking quality was the best in the stalk curing.

버어리종 잎담배의 건조조건이 정유성분 조성에 미치는 영향

배성국,김도연,이윤환,김영회 한국연초학회 2002 한국연초학회지 Vol.24 No.2

This study was performed to investigate the influence of curing conditions on the composition of essential oil during curing process of burley tobacco leaves. The curing conditions were the primed curing in vinyl house (house-curing), air-curing barn (air-curing) and stalk-curing in conventional curing house (stalk-curing). Total 90 compounds are identified from the steam volatile oils of harvest and cured tobacco leaves by GC and GC-MS, respectively. The major components were neophytadiene, hexadecanoic acid, 3,8,13-duvatriene-1,5-diols, oxide-9-methylene-3,13-duvadienols, solanone, megastigma-4,6,8-trien-3-ones, phenylacetaldehyde, $\beta$-phenylethyl alcohol, indole, dihydroactinidiolide and phytol. The amount of alcoholic compounds was decreased more than approximately 50% in cured leaves without regard to the curing conditions. $\beta$-Phenylethyl alcohol and 3,8,13-duvatriene-1,5-diols were decreased more in air curing and stalk curing than in house curing. The amounts of phenylacetaldehyde, solanone, $\beta$-damascone, $\beta$ -damascenone, oxysolanone and megastigma-4,6,8-trien-3-ones as ketonic compounds, dihydroactinidiolide and indole as miscellaneous compounds in air-cured and stalk-cured tobacco leaves were 2 times higher than those in house-cured leaves, while esteric and acidic compounds were not changed largely in content by curing conditions.

완속기시(Soft-start)광조사 방식이 복합레진의 중합 및 수축응력에 미치는 효과

위유민,오유향,이난영,이창섭,이상호 大韓小兒齒科學會 2005 大韓小兒齒科學會誌 Vol.32 No.2

본 연구에서는 기존의 할로겐 광중합기를 이용하여 40초간 조사하여 복합레진을 중합한 경우와 플라즈마 광중합기를 이용한 고강도의 중합 및 완속기시 중합 방식, 그리고 LED 광중합기를 이용한 통법의 중합과 완속기시 중합 방식으로 복합레진을 중합하여 발생되는 수축응력을 비교하고 미세경도를 측정하여 중합도를 평가하였다. 내경 7mm, 외경 10mm의 아크릴릭 주형을 제작하고 외면에 스트레인게이지를 부착 시킨 뒤 각각의 광원에 따른 중합모드로 광중합 하였다. 광조사 시점부터 1초 간격으로 600초간 수축응력을 측정하였으며, 중합 24시간 후 각 군의 미세경도를 측정하여 통계 분석하였다. 수축응력 측정 후 시편을 종단하여 주사전자현미경으로 레진수복물과 아크릴릭 주형 계면을 관찰하였다. 이상의 실험을 통해 얻은 결과는 다음과 같다. 1. 플라즈마 광과 LED 광원의 완속기시 중합방식은 각각의 기본 중합방식에 비해 중함 10분 후에 수축응력 감소를 보였다(P<0.05). 2. 완속기시 중합방식의 플라즈마 광이 가장 낮은 수축응력을 보였으나 미세경도 또한 가장 낮았다(P<0.05). 3. 완속기시 중합방식의 LED 광중합은 기존의 할로겐 광과 LED 광중합 방법에 비하여 낮은 수축응력을 보였다(P<0.05). 4. 완속기시 중하장식의 LED 광으로 조사한 시편의 미세경도는 단일광도로 조사한 할로겐 광과 LED 광중합과 비교하여 유의할만한 차이가 나타나지 않았다(P>0.05). 5. 기존의 할로겐 장과 완속기시 중합방식의 LED로 중합한 시편이 플라즈마 광과 단일강도의 LED로 조사한 군보다 더 나은 번연봉쇄를 보였다. The purpose of this study was to evaluate the influence of soft-start light curing on contraction stress and hardness of composite resin. Composite resin mold was cured using the one-step continuous curing method with three difference light sources; conventional halogen light curing for 40 seconds at 400 mw/㎠, plasma arc light curing for 6 seconds at 1300 mW/㎠ and LED light curing for 10 seconds at 700 mW/㎠. For the soft-start curing method 2 seconds light exposure at 650 mW/㎠ followed by 3 seconds at 1300 mW/㎠ and exponential increase with 5 seconds followed by 10 seconds at 700 mW/㎠ were used. Contraction stress was measured using strain gauge method and Vickers hardness was measured 24 hours after polymerization at the top and bottom of specimens. Resin-acrylic interfaces were observed using a scanning electron micro scope(SEM). The results of present study can be summarized as follows: 1. Contraction stresses at 10 min after polymerization were significantly reduced with the soft-start curing both in plasma and LED light sources(P<0.05). 2. Plasma light curing with soft-start resulted in not only the lowest contraction stress, but also the lowest hardness (P<0.05). 3. LED light curing with soft-start showed lower contraction stress than the one-step continuous halogen and LED light curing(P<0.05). 4. Micro hardness of specimens cured by LED light with soft-start was equivalent to that of cured by the one-step continuous halogen and LED light(P>0.05). 5. Curing by LED light with soft-start and conventional halogen light resulted in better marginal sealing than plasma light and one-step LED light curing.

촉진양생이 콘크리트의 28일 압축강도에 미치는 영향에 관한 연구

최세규,유승룡,김생빈 한국콘크리트학회 1996 콘크리트학회지 Vol.8 No.4

기존의 촉진양생 연구는 1960~1970년대에 주로 실행된 것으로, 전체 증기양생기간이 18시간 또는 24시간인 경우에 대하여 연구되었고, 상기 연구 결과는 수동식 항온항습조를 사용하였으므로 온도상승구배의 효과에 대하여 명확한 규명을 할 수 없다고 판단되었다. 따라서 국내 PC공장 여건에서 그 직접적인 적용이 불가능한 실정이다. 본 연구는 효과적인 콘크리트 촉진양생에 대한 기본 자료를 정립할 목적으로, 국내 PC 공장에서 사용하는 배합표를 근거로 시험공시체를 제작한 후, 각 해당 양생주기 조건을 변화시켜 가면서 실험하였다. 탈형시 및 수중양생 재령28일의 측정하고 비교 검토한 결과, 재령 28일 후 설계강도값을 초과하는 가장 효과적인 촉진양생조건, 본 실험조건 하에서 전양생시간은 커다란 영향을 미치지 않았으며, 온도상승구배는 $30^{circ}C/hr$ 이하로, 최고양생온도는 $82^{\circ}C$이하로 양생해야 하며, 또한 촉진양생 후 2차 양생으로 강도증진을 도모함이 촉진양생의 효과를 증대시킬 수 있다고 판단되었다. The pulished works on Accelerated Curing Effect were generally performed around from 1960 to 1970th century for 18 to 24 hours - total curing periods. It is not possible to define the effect of temperature rise because those results were obtaine mainly by using the manually operated steam-curing tank. Thus, it may not be available to apply those data immediately on the domestic PC wall production line. The testing specimens were made from the standard mix proportion according to those of domestic PC factories to establish a basic data for the Accelerated Curing Effect. The experimental tests were conducted according to the conditions of each sub-curing periods. By comparing the results of compression tests on de-molded and 28-day water-curing specimens, we find that the most effective curing condition to obtain more than the required design strength after 28 day of water curing may be as follows: the presteaming period does not affect seriously and less than$30^{circ}C/hr$- the rate of temperature rise andless than $82^{circ}C$ - maximum temperature are necessary. It seems that post-curing procedure is very important factor to increase the effect of accelerated curing.

LED 광중합기의 조사 mode가 복합레진의 미세경도 및 수축응력에 미치는 영향

박인호,오유향,이난영,이창섭,이상호 大韓小兒齒科學會 2005 大韓小兒齒科學會誌 Vol.32 No.2

이 연구의 목적은 LED 광중합기(Elipar Freelight 2?, 3M-ESPE, USA)의 조사 mode에 따른 복합레진(Supreme?, Filtek Flow?, 3M-ESPE USA)의 수축응력과 미세경도를 평가하는 것이다. 수축응력을 측정하기 위해 스트레인 게이지가 사용되었다. 표본은 조사 mode와 충전방법에 따라 6개의 군으로 나누어졌다. A군: Filtek Flow?이장, Supreme? 충전, 10초 광중합, B군: Filtek Flow?이장, Supreme? 충전, 15초 광중합, C군: Filtek Flow?이장, Supreme?충전, 15초 soft start 광중합, D군 Supreme? 충전, 10초 광중합, E군: Supreme?충전, 15초 광중합, F군: Supreme?충전, 15초 soft start광중합. 스트레인 게이지를 아크릴릭 링에 부착하고 strain meter에 연결한 후 광중합하고 10분 동안 1초 간격으로 측정하고 기록하였다. 24시간 후에 각각 표본의 미세경도를 측정하였다. 결과는 ANOVA와 Tukey test를 이용해 통계학적으로 분석하였다. 결과는 다음과 같았다. 1. Soft start curing 했을 때 수축응력 이 낮았다(p<0.05). Flow able resin을 이장한 군에서는 효과가 없었다. 2. 10초간 조사한 군은 15초간 조사한 군에 비해 수축응력이 적었다(p<0.05) 3. 미세경도 측정결과 상면과 하면에서 각 군 간에 차이는 없었다(p>0.05). 하지만, 하면의 미세경도가 상면에 비해 80%에 이르지 못했다. The purpose of this study was to evaluate the polymerization contraction and the micro hardness of composite resin(Supreme?, Filtek Flow?, 3M-ESPE, USA) according to irradiation modes of LED curing unit(Elipar Freelight?, 3M-ESPE, USA). The strain guage method was used for determination of polymerization contraction. Sample were divided by 6 groups according to curing modes and filling method. Group A: Supreme?, Filtek Flow? lining, 10seconds curing, Group B: Supreme?, Filtek Flow? lining, 15seconds curing, Group C: Supreme?, Filtek Flow? lining, 15seconds soft start curing, Group D: Supreme? only, 10seconds curing, Group E: Supreme? only, 15seconds curing, Group F: Supreme? only, 15seconds soft start curing Preparations of acrylic molds were followed by filling and curing. Strain guage attached to each sample were connected to a strain meter. Measurements were recorded at each second for the total of 10 minutes including the periods of light application. And micro hardness of each group after 24hours from light irradiation were measured. Obtained data were analyzed statistically using Repeated measures ANOVA and Tukey test. The results of the present study are as follows: 1. In flow able resin liner group, soft start curing group was not found decrease of polymerization contraction. But, In Supreme only filling group, the lowest polymerization contraction was found in soft start curing group. 2. 10 seconds curing group showed statistically significant reduction of polymerization contraction compared with 15 seconds curing group(p<0.05). 3. The micro hardness values of each group not revealed significant difference(p>0.05). But, lower surface micro hardness was not reached 80% of upper surface micro hardness.