• Title/Summary/Keyword: internal curing

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Effect of Carbon on the Micro Structure and Hardness of Internally Hardened Ductile Cast Iron Roll (내부 경화형 구상흑연주철 롤 동체와 넥의 미세조직과 경도에 미치는 탄소 영향)

  • Sang-Mook Lee;Ki-Hang Shin;Byung-Chul Choi;Ki-Woo Nam
    • Journal of the Korean Society of Industry Convergence
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    • v.26 no.1
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    • pp.79-86
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    • 2023
  • This study was investigated the effect of carbon on the micro-structure and hardness of ductile cast iron roll with internal curing capacity. Spheroidal graphite existed at roll body with rapid cooling, but granular graphite existed at roll neck with slow cooling. The volume fraction of graphite increased at roll body with rapid cooling, That of roll neck with slow cooling decreased, but graphite size increased. The volume fraction of cementite decreased, but volume fraction increased. The cementite size was larger at roll neck than roll body. The hardness was decreased at roll body and roll neck due to volume fraction of cementite. The hardness of roll body was higher than roll neck.

Properties of Matrix According to the Replacement Ratio of Portland Cement-based Carbonation Sluge (시멘트 기반 탄화슬러지 치환율에 따른 경화체의 특성)

  • Kang, Yong-Mo;Lee, Hye-Eun;Lee, Sang Soo
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2021.05a
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    • pp.189-190
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    • 2021
  • Recently, the spread of intense social distancing and untact culture due to COVID-19 has increased the time spent indoors. In addition, according to the International Cancer Institute, fine dust was classified as a first-class carcinogen, a substance found to be carcinogenic, such as asbestos and benzene. As a result, interest in indoor air quality is increasing, and many studies are underway to reduce air pollutants. This study is a basic experiment of a board made to improve indoor air quality. The basic characteristics of the board, flexural strength and compressive strength, are analyzed and the results of the test are as follows. Experiments have shown that flexural strength and compressive strength tend to decrease as the replacement rate of hydrocarbons increases. It is believed that the strength of the sludge has decreased due to the increase in internal voids due to the increase in non-surface area, volume and diameter of microfiber as it undergoes the carbonation process. In addition, it is believed that the amount of moisture needed for curing during the mixing process was reduced due to the absorption of hydrocarbons.

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Hyeongok's Pyeongshintang was combined according to the theory for properties and tastes of herbal medicines (현곡(玄谷) 평신탕(平腎湯)의 구성한약과 그 기미배오(氣味配伍) 분석)

  • Tsung, Pei-Chin;Song, Choon-Ho;Kim, Bo-Kyung;Xie, Chun-Jiao;Shin, Woo-Jin;Park, Dong-Il;Shin, Soon-Shik
    • Herbal Formula Science
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    • v.16 no.2
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    • pp.91-100
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    • 2008
  • Background and Objectives : There are three kinds of formulas for purging the kidney to cure its sthenic syndrome based on the types of preparation formulas : Sashintang, Sashinhwan and Sashinsan. There are 4 kinds of Sashintang, 1 kind of Sashinhwan and 1 kind of Sashinsan. Combination of herbal medicines, carried out in formulas for purging the kidney, consists of various kinds depending on medical scientists' personal experience in medical treatment without any general principles, which makes it difficult to apply it to clinical use. The objectives of this study lie in theoretical establishment of Pyeongshintang for curing the sthenic syndrome of kidney through analyzing the component medicines and combination principles of Hyeongok's Pyeongshintang, and furthermore, maximizing the clinical use of Pyeongshintang. Methods : This study analyzed the component medicines and combination principles of Hyeongok's Pyeongshintang based on the theory for properties and tastes of herbal medicines from the "Yellow Emperor's Canon of Internal Medicine", the theory for principal herbal medicine, assistant herbal medicine, adjuvant herbal medicine, dispatcher herbal medicine, and the five elements doctrine. Hyeongok's Pyeongshintang is an odd prescription, composed of 7 kinds of ingredients : No.1 Rhizoma Alismatis (2don;7.5g), No.2 Poria (1don;3.75g), No.3 Radix Paeoniae Alba (1don), No.4 Fructus Chaenomelis (1don), No.5 Polyporus (1don), No.6 Cortex Cinnamomi (1don), and No.7 Radix Glycyrrhizae (1don) Results : There are three methods for curing the sthenic syndrome of kidney according to the five elements doctrine : purging the kidney, purging the liver and invigorating the spleen. First, if you suffer from the sthenic syndrome of the kidney, you need to purge your kidney. There are two available methods, including taste and property purgation according to the theory for properties and tastes of herbal medicines. They each imply the salty taste and the hot property purge the kidney. In the case of taste purgation, two herbal medicines with salty taste, Rhizoma Alismatis and Poria, are combined into the principal and assistant herbal medicine, respectively. For property purgation, two herbal medicines with the hot property, Polyporus and Cortex Cinnamomi, are combined into adjuvant herbal medicines. Secondly, if you suffer from the sthenic syndrome of the kidney, you need to purge your liver which is child in the mother-child relationship in inter-promotion among the five elements. There are two methods to purge the liver, including taste and property purgation according to the theory for properties and tastes of herbal medicines. They each mean the sour taste and the cool property purge the liver. Therefore, it is important to use sour herbal medicines for taste purgation and cool ones for property purgation. Both sour and cool herbal medicines, Radix Paeoniae Alba and Fructus Chaenomelis, are combined into adjuvant herbal medicines. Lastly, if you suffer from the sthenic syndrome of the kidney, you need to invigorate your spleen which is an element being surpassed in the relationship between the elements surpassed and ones not surpassed in inter-restraint among the five elements. There are two methods to invigorate the spleen, which include taste and property invigoration according to the theory for properties and tastes of herbal medicines. Taste invigoration means to invigorate the spleen with sweet taste and property invigoration to invigorate the spleen with warm property. Therefore, it is important to use sweet herbal medicines for taste invigoration and warm ones for property invigoration. Both sweet and warm herbal medicines, Polyporus and Cortex Cinnamomi, were combined to invigorate the spleen and purge the kidney. In addition, Radix Glycyrrhizae are combined as dispatcher herbal medicine, harmonizing all the herbal medicines composing the formula. Conclusions : First, to cure the sthenic syndrome of the kidney, the methods of purging the kidney and the liver, and invigorating the spleen should be used according to the five elements doctrine. Secondly, herbal medicines appropriate for those treatment methods should be chosen according to the theory for properties and tastes of herbal medicine and thirdly, the combination of those herbal medicines should be carried out according to the theory for principal herbal medicine, assistant herbal medicine, adjuvant herbal medicine, dispatcher herbal medicine. As a good example, Hyeongok's Pyeongshintang is combined according to the above theories. In conclusion, this formula was created by applying to the theory for properties and tastes of herbal medicines.

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An Advanced Assessment Strategy of Thermal Cracks Induced by Hydration Heat and Internal Restraint (내부구속에 의한 수화열 균열의 개선된 평가 방법)

  • Jeon, Se-Jin;Choi, Myoung-Sung;Kim, Young-Jin
    • Journal of the Korea Concrete Institute
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    • v.18 no.5 s.95
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    • pp.677-685
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    • 2006
  • Control of the temperature difference across a section is an effective strategy to minimize the hydration-heat-induced cracks for the structures where internal restraint is dominant. The domestic code, however, overestimates probability of the crack occurrence judging from the foreign codes and construction experiences of real structures. Therefore, the background of the equation presented in the domestic code was investigated step by step to examine validity of the equation, and, as a result, it was found that the equation is established on a basis of simple elastic model where the change of elastic modulus in an early age is not considered. An advanced assessment strategy was proposed taking into account the hypoelastic model which corresponds to an incremental constitutive equation. The presented procedure resulted in an increased crack index, i.e. decreased crack risk, the value of which depends on various conditions of the mix and structures. Also, a prediction equation of the temperature difference was proposed which can readily consider the effect of the curing condition and ambient temperature in a hand calculation. For further study, the assessment equation may be more classified to strictly consider the characteristics of the mix and structures if the analytical and experimental data are accumulated.

A Study on the prescriptions of 『Sanbeon-bang(刪繁方)』 (『산번방(刪繁方)』의 의방(醫方)에 관한 연구)

  • Kim, Do-Hoon;Jeong, Chang-Hyun
    • The Journal of Korean Medical History
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    • v.17 no.2
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    • pp.111-127
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    • 2004
  • This paper is mainly on the rsearch of the prescriptions of "Sanbeon-bang(刪 繁方)". For the research of prescription, investigated "Sanbeon-bang" from the side of symptoms of a disease, number of drugstuffs, table of contents, drugstuffs and acupuncture and moxibustion. With these investigation, made out a few tables, and with these tables made an attempt to understand the whole prescriptions of "Sanbeon-bang". "Sanbeon-bang" is of rich contents in internal medicine. Among internal medicine, related to Oro-Yukgeuk-Chilsang(五勞-六極-七傷) was most abundant. So we can guess "Sanbeon-bang" was a medical book specialized in exhaustion syndromes. It also deals with the Samcho-syndromes, as investigate from medical comments, has the perfect system of prescription in relative. From the investigation of the combination of drugstuffs, ascertained that, the number of simple prescription composed of one drugstuff was 38, combinational prescription composed of two drugstuffs was 9, minor prescription composed of three to five drugstuffs was 47, midum prescription composed of six to ten drugstuffs was 95, major prescription composed of eleven to twenty drugstuffs was 45, and mixed prescription composed over twenty drugstuffs was 1. Mentionable unique prescriptions in internal use were the forms of keeping in mouth. In external use they were fumigants, suppositories, powdered medicines, spraying the granular medication into the nasal cavity and eyedrops. And were abundant in soft extract(ointment) and plaster. In addition, there were the recordings of 18 types of cellulitis, types of incurable cellulitis and curing an illness by a charm. By the way, when comparing "Sanbeon-bang" with "Cheongeum-bang", all of which was quoted a lot in "Oedaebiyo-bang", "Cheongeum-bang" rather took medical comments of "Sanbeon-bang" than prescription. Although there were some prescriptons in "Sanbeon-bang" at the same category, "Cheongeum-bang" took another prescriptions which are more complexed than those of "Sanbeon-bang". In the same way, when comparing "Cheongeum-bang" with "Sonjinin-Cheongeum-bang(孫眞人千金方)", which didn't go through the correction of GyojeongUiseoguk of Bug-Song goverment, "Cheongeum-bang" often didn't take the prescriptions of "Sonjinin-Cheongeum-bang". Hence we can guess, "Cheongeumyo-bang" may have added a lot of prescriptions when undergoing the correction of of GyojeongUiseoguk. The total number of species of drugstuffs in "Sanbeon-bang" from the investigation was 284. The plant drugs were 208 species, the animal were 31 species, the minerals were 19 species and the other were 26 species. The prescriptions related to acupuncture and moxibustion in "Sanbeon-bang" were only moxibustional prescriptions. Which appeared one time per exhaustion and steaming of bone syndrome, Oro-Yukgeuk-Chilsang and Samcho syndrome. Appeared six times in muscle syndromes. But I cannot imagine the original form of acupuncture and moxibustion in "Sanbeon-bang" for deficiency of data.

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A Study on the '$\bar{A}yurveda$' (아유르베다'($\bar{A}yurveda$)에 관한 소고(小考))

  • Kim, Ki-Wook;Seo, Ji-Young;Park, Hyun-Kuk
    • The Journal of Dong Guk Oriental Medicine
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    • v.10
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    • pp.161-175
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    • 2008
  • The '$\bar{A}yurveda$', Buddhistic medicine, and the present of traditional medicine can be summed up as thus. 1. The '$\bar{A}yurveda$' is a transliteration of the Sanskrit Ayur - veda and is a compound of the words 'Ayus(life)' and 'Veda(knowledge)' and means "The study of life", which means the preservation of health and the understanding and curing of diseases. 2. The '$\bar{A}yurveda$', which originated from ancient experience, was recorded in Sanskrit, which was a theorization of knowledge, and also was written in verses to make memorizing easy, and made medicine the exclusive possession of the Brahmin. The first annotations were 1060 for the "Charaka", 1200 for the "Sushruta", 1150 for the "Ashtanga Sangraha samhita", and 1100 for the "Nidana". The use of various mineral medicines in the "Charaka" or the use of mercury as internal medicine in the "Ashtanga Sangraha samhita", and the palpation of the pulse for diagnosing in the '$\bar{A}yurveda$' and XiZhang' medicine are similar to TCM's pulse diagnostics. The coexistence with Arabian 'Unani' medicine, compromise with western medicine and the reactionism trend restored the '$\bar{A}yurveda$ today. 3. When we look at the present of the education and research of the '$\bar{A}yurveda$', after gaining independence from England, India set up a modern education system of the '$\bar{A}yurveda$' and set it on an equal position with western medicine. According to the 1976 study the '$\bar{A}yurveda$' is taught in a 5 and a half year university curriculum, and the main textbooks are the Charaka - samhita("開羅迦集" - internal medicine), Sushruta-samhita("妙聞集", surgery), Madhavanidana(diagnostics), 3 volumes of Bhavaprakasa(pharmacology internal medicine, mineral medicine}, Rajanighantu (pharmacology), $Vrks\bar{A}yurveda$(plant therapy), Mahabharata(military medicine), Arthasastra(forensic medicine, toxicology) Kamasastra(science of intercourse), etc. in 10 subjects and there are 232227 certified doctors that have graduated from the 95 colleges and passed the exams.

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Physical Properties of Lightweight and Normal Weight Concretes due to Water-Cement Ratio Changes (물-시멘트비 변화에 따른 경량콘크리트와 일반콘크리트의 물리적 성질)

  • Lee, Chang-Soo;Kim, Jae-Nam;Lim, Youn;Ma, Moon-Hak
    • Journal of the Korean Society of Hazard Mitigation
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    • v.9 no.4
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    • pp.11-20
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    • 2009
  • By using the artificial lightweight aggregate for the natural aggregate depletes and destruction of environment and the application of lightweight concrete in structure, the lightweight concrete is manufactured. The fundamental characteristics by the waterbinder ratio was evaluated. It is suggested the method to control of pre-absorbed water of the lightweight aggregate. Lightweight concrete with pre-absorbed aggregate has similar characteristics compared to normal weight concrete regardless of water-binder ratio. According to the water-binder ratio, the drying condition, and the rebar, the unit mass of the lightweight concrete showed the reduction of 14.6${\sim}$21.0% as the range of 1,668${\sim}$1,998 $kg/m^3$ in comparison to the normal weight concrete. The lightweight aggregate pre-absorbed water showed the deferent evaporation quantity according to the water-binder ratio. As the water-binder ratio is lower, the oven dry vapour water is larger, therefore the internal curing water is increasing. In the same water-binder, comparing the normal concrete the lightweight concrete shows lower compressive strength which is due to the different strength of an aggregate. In the air dry curing, the normal weight concrete has a lower strength improvement effect in w/c 0.3 than the ratio 0.4 and 0.5. However, the strength improvement effect has increasing as the water-binder ratio was low in the light concrete.

(Photosensitive Polymers VII) Mechanism of Photosensitized Curing Reaction of Cinnamoylated Polymers ((感光性 高分子에 關한 硏究 VII) Cinnamoylated Polymers의 光增感 硬化反應機構)

  • Kim, Kwang-Sup;Shim, Jyong-Sup
    • Journal of the Korean Chemical Society
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    • v.10 no.4
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    • pp.166-174
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    • 1966
  • The multistep mechanism of photosensitized curing reaction cinnamoylated photosensitive polymer is proposed from the energy level diagram of cinnamic acid and sensitizer, and from the fact that excess of sensitizer brings the sensitivity to a limiting value etc. Various factors which have effects on the ability of sensitizer are also discussed. The mechanism involves following steps: activation to the first excited singlet states of cinnamoyl group(C) and sensitizer(S) by their absorption of photon, their intersystem crossing to the lowest triplet state, bimolecular internal quenching by formation of excimer of sensitizer, triplet excitation energy transfer and intermolecular addition between cinnamoyl group in ground state and that in triplet state. The rate equation derived from this mechanism is $-\frac{d[C]}{dt} = \frac{K_1[C]}{K_2 + [C]}[\frac{I^c_{abs}}{K_3 + [S]} + \frac{K_4[C]}{(K_5 + [C])(K_6 + [S])}(I^s_{abs} + \frac{K_7I^c_{abs}[S]}{K_8 + [S]})]$ where $I^c_{abs}\;and\;I^s_{abs}$: the rates of absorption of photon by cinnamoyl group and sensitizer $K_n$: Constants. It is proved with the cinnamate of poly(glyceryl phthalate)(PGC) in the absence of sensitizer using the infrared analytical method and successfully applied for the experimental data reported on the effects of the degree of cinnamoyl esterification and the concentration of sensitizer upon the sensitivity.

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Postharvest Handling and Marketing Management for Making High Salability of Sweetpotatoes (상품성 제고를 위한 고구마 수확 후 관리 및 출하기술)

  • Jeong, Byeong-Choon
    • Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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    • 2001.06a
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    • pp.51-64
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    • 2001
  • The qualities including taste of sweetpotato stored during the winter which can display in the spring market in Korea are affected by availability of storage for the roots. In order to make high storage availability of sweetpotato, the postharvest handlings should be done thoroughly from the moment of harvest until shipping them to the market. A lot of procedures that must be handled carefully for improving postharvest management are as follows; digging, trimming, gathering, putting in storage containers, carrying them from field to house, curing, storing, washing, drying, selecting marketable roots, packing and shipping to the market, etc.. Sweetpotatoes have a high moisture content, and a relatively thin and delicate skin, and are sensitive to chilling, so careless postharvest handling can lead to both quantitative and qualitative losses which may be extremely high in some circumstances. From now on research has concentrated on the improvement of postharvest conditions to increase yield and lower disease rates. Storage, which makes sweetpotatoes available through out the year, benefits both the producer and the consumer. Seven very important points must be needed in order to get the best quality marketable roots in the storing of sweetpotatos : $\circled1$The storage house must be clean and sanitary, $\circled2$The crop must be harvested before the first frost to avoid low-temperature injury, $\circled3$Particular care must be taken to avoid cutting, bruising, or other injuries of the sweetpotatoes during digging, picking up, grading, placing in containers, and moving to the storage house, $\circled4$Select sound, disease-free roots for storage $\circled5$Sweetpotatoes should be stored in properly stacked containers $\circled6$Cure immediately after harvest, preferably at 32∼33$^{\circ}C$ and 90 to 95 percent relative humidity for 4 to 7 days, After curing the temperature should be reduced to 13$^{\circ}C$ to 16$^{\circ}C$ by ventilating the storage with outside air. $\circled7$Store at 12$^{\circ}C$ to 14$^{\circ}C$ and a relative humidity of 80 to 85 percent. Storage houses should be located on suitable sites and should be tightly constructed and insulated so that temperature and humidity will be uniform. Sweetpotatoes are usually not washed and graded, and lately sometimes washed, graded, waxed, before being shipped to market. Consumer packaging of sweetpotatoes in paper boxes(10-15kg) or film bags is done mainly to aid marketing. The shelf life of washed roots in consumer packs in only 1 to 2 weeks. Weight loss of roots during marketing is much less in perforated film bags than in mesh and paper bags. Perforation of 0.8 to 1kg polyethylene bags with about six 6mm holes is essential ; to lower the internal relative humidity and avoid excessive sprouting, rooting, and dampness. Development and use of better postharvest handling with good storage facilities or marketing methods can minimize sweetpotate losses and has an effect of indirectly increasing productivity and farmer’s income.

Experimental Study for Evaluating Early Age Shrinkage of Mortar for 3D Printing (3D 프린팅용 모르타르의 초기재령 수축거동 평가를 위한 실험적 연구)

  • Seo, Eun-A;Yang, Keun-Hyeok;Lee, Ho-Jae
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.26 no.2
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    • pp.76-83
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    • 2022
  • Since the 3D printing mortar is exposed to the atmosphere immediately after printing, moisture is largely evaporated from the surface of the layer. The evaporation of moisture on the surface of the layer greatly causes drying shrinkage and increases the risk of cracking and damage to the structure due to drying shrinkage. This study experimentally evaluated the shrinkage behavior of the initial age using the mortar used for 3D printing. The change in shrinkage was evaluated by comparing the shrinkage of the specimen cured by the sealing method and the atmospheric exposure method. In addition, compared with the case where type 1 cement was used 100%, the shrinkage amount was evaluated when 20% of fly ash was replaced and 10% of silica fume was used. In particular, the effect of three chemical admixtures applied using 3D printing on shrinkage was evaluated experimentally. When fly ash and silica fume were used, the shrinkage amount increased by 60 - 110% compared to the case when type 1 cement was used. The application of viscosity modifiers and shrinkage reducers reduced the shrinkage by at least 18% and at most 70% depending on the curing conditions. The temperature of the specimen temporarily decreased to 15 ℃ at the beginning of curing, and the correlation between the internal temperature of the specimen and the shrinkage behavior was observed.