• Title/Summary/Keyword: Physical properties test

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Evaluation of Setting Time, Solubility, and Compressive Strength of Four Calcium Silicate-Based Cements (네 가지 규산 칼슘계 시멘트의 경화시간, 용해도, 압축강도 평가)

  • Yuji Jang;Yujin Kim;Junghwan Lee;Jongsoo Kim;Joonhaeng Lee;Mi Ran Han;Jongbin Kim;Jisun Shin
    • Journal of the korean academy of Pediatric Dentistry
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    • v.50 no.2
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    • pp.217-228
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    • 2023
  • This study aimed to compare the physical properties of 4 kinds of calcium silicate-based cements (CSCs): 2 kinds of powder-liquid mix type (RetroMTA® [RTMX] and Endocem® MTA Zr [EZMX]) and 2 kinds of premixed type (Well-RootTMPT [WRPR] and Endocem® MTA premixed [ECPR]) CSCs, respectively. Further, we assessed the setting times, solubility values, and compressive strengths of the cements. The shortest setting time was observed for EZMX (123.33 ± 5.77 seconds), followed by RTMX (146.67 ± 5.77 seconds), ECPR (260.00 ± 17.32 seconds), and WRPR (460.00 ± 17.32 seconds), respectively. The highest solubility was observed for WRPR (9.01 ± 0.55%), followed by RTMX (2.17 ± 0.07%), EZMX (0.55 ± 0.03%), and ECPR (0.17 ± 0.03%). Furthermore, the highest compressive strength was observed for ECPR (76.67 ± 25.67 Mpa), followed by WRPR (38.39 ± 7.25 Mpa), RTMX (35.07 ± 5.34 Mpa), and EZMX (4.07 ± 0.60 Mpa). In conclusion, the premixed type CSCs (WRPR and ECPR) exhibited longer setting times compared to the powder-liquid mix type CSCs (EZMX and RTMX). The solubility test showed that ECPR had the lowest solubility while WRPR had the highest solubility, with a statistically significant difference between them (p < 0.0083). Additionally, the compressive strength test showed that ECPR had the highest compressive strength, while EZMX had the lowest compressive strength, also with a statistically significant difference between them (p < 0.0083). ECPR is a promising material as it is premixed, eliminating the need for mixing time, and it has also demonstrated improved solubility and compressive strength, making it a potentially favorable option for clinical use.

Characteristics of Polyester Polymer Concretes Using Spherical Aggregates from Industrial By-Products (III) (Using an Atomizing Steel Slag as a Filler and Fine Aggregate) (산업부산물 구형골재를 사용한 폴리에스테르 폴리머 콘크리트의 특성(III) (아토마이징 제강슬래그를 충전재와 잔골재로 사용))

  • Hwang, Eui-Hwan;Kim, Jin-Man
    • Applied Chemistry for Engineering
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    • v.26 no.1
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    • pp.104-110
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    • 2015
  • It is known that polymer concretes are 8~10 times more expensive than ordinary Portland cement concretes; therefore, in the production of polymer concrete products, it is very important to reduce the amount of polymer binders used because this occupies the most of the production cost of polymer concretes. In order to develop a technology for the reduction of polymer binders, smooth and spherical aggregates were prepared by the atomizing technology using the oxidation process steel slag (electric arc furnace slag, EAFS) and the reduction process steel slag (ladle furnace slag, LFS) generated by steel industries. A reduction in the amount of polymer binders used was expected because of an improvement in the workability of polymer concretes as a result of the ball-bearing effect and maximum filling effect in case the polymer concrete was prepared using the smooth and spherical atomized steel slag instead of the calcium carbonate (filler) and river sand (fine aggregate) that were generally used in polymer concretes. To investigate physical properties of the polymer concrete, specimens of the polymer concrete were prepared with various proportions of polymer binder and replacement ratios of the atomized reduction process steel slag. The results showed that the compressive strengths of the specimens increased gradually along with the higher replacement ratios of the atomized steel slag, but the flexural strength showed a different maximum strength depending on the addition ratio of polymer binders. In the hot water resistance test, the compressive strength, flexural strength, bulk density, and average pore diameter decreased; but the total pore volume and porosity increased. It was found that the polymer concrete developed in this study was able to have a 19% reduction in the amount of polymer binders compared with that of the conventional product because of the remarkable improvement in the workability of polymer concretes using the spherical atomized oxidation steel slag and atomized reduction steel slag instead of the calcium carbonate and river sand.

Assays of Maturity and Antifungal Activity against Plant Pathogen during the Animal Manure Composting Process (가축분 퇴비화 과정에서 부숙도 및 퇴비의 항균활성 검정)

  • Seo, Myung-Chul;So, Kyu-Ho;Park, Won-Mok
    • Korean Journal of Soil Science and Fertilizer
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    • v.32 no.3
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    • pp.285-294
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    • 1999
  • Changes of chemico-physical properties and mturitiy during pig manure composting were analysed using three kinds of bulking agents with rice hull(T1), rice hull and extruding hull mixture (T2, 1:1, v/v), and extruding hull(T3). During composting process, temperature of T1, T2 and T3 were maintained over $50^{\circ}C$ for 31, 21, and 35 days respectively. Organic matter content of each treatment was decreased from 82.2%, 82.0%, and 82.8% to 70.5%, 68.9% and 69.7% and pH increased to 8.85, 9.91, and 8.80, respectively. Total nitrogen content of all treatments gradually decreased, but C/N ratio, phosphorous, and potassium content did not, show any changes during composting process. Both germination rate and early growth were tested using radish seeds for composting maturity. From those results, it was concluded that all treatments were stabilized after 45th day and extruding hull(T3) added compost was superior to others. The test of suppressive effect showed that all treatment have no effect against Fusarium oxysporum, Alternaria altemata, Botrytis cinerea. Compost supplemented with rice hull showed an inhibitory effect after 30th days, while compost supplemented with rice hull and extruding hull(T2) had an inhibitory effect during all period against Rhizoctonia solani. But treatment with extruding hull(T3) added compost did not have any inhibitory effect against Rhizoctonia solani. Only 63th samples in T1 and T2 treatment showed inhibitory effect against Colletoerichum gloeosporioides. However, T3 did not. Suppressive effect of extracts from 67 kinds of composts was investigated in vitro against plant pathogens, such as Fusauum oxysporum. Alternaria alternata, Colletotrichum gloeospoioides, Rhizoctonia solani, and Botrytis cinerea. Thirty two of them showed inhibitory effect against more than one phytopathogen, nine against one pathogen, four against two, six against three, six against four, and seven against five.

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Physicochemical properties of dacquoise made with sugar or sugar replacements, tagatose, and erythritol (타가토스와 에리스리톨로 제조한 다쿠아즈의 물리화학적 특성 연구)

  • Lee, Na Ra;Kang, Suna;Kim, Ji Hyun;Kim, Ha Hyoung;Lee, Jung Ah;Park, Sunmin
    • Journal of Applied Biological Chemistry
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    • v.60 no.1
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    • pp.87-93
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    • 2017
  • The objective of this study was to investigate the physicochemical characteristics and sensory evaluation of dacquoise made with sugar or sugar replacement (tagatose, erythritol). Sugar (S) was replaced with tagatose (T), and sugar powder was replaced with tagatose (TS), and erythritol (TE). S showed the highest sugar contents compared with TS and TE (p <0.05) but there were no significant differences with T. There were not significant differences in specific gravity and spread factor among the sweeteners. S and T tended to have higher loss factors than TS & TE. The more tagatose was increased, the more the redness value increased compared with S, and sucrose showed similar tendency for lightness (redness; TS > T > TE > S, lightness; S > T > TS > TE). TE showed good results for physical characteristics whereas T was better in the sensory test. The above results bear out that tagatose and erythritol both are suitable as alternative sweeteners for making dacquoise, but tagatose was better. Tagatose appeared to be a better replacement for sucrose in baking dacquoise, and dacquoise with 33% of the sugar replaced tagatose (T) could be suitable for use by diabetic and obese people. 95.1% tagatose (TS) maybe appropriate for diabetic patients. In conclusion, tagatose is a suitable sugar replacement for making dacquoise.

Effects of Application Method of Dairy Liquid Manure on Productivity of Silage Corn and Sorghum × Sudangrass Hybrid and Soil Characteristics (젖소액비 시용방법이 담근먹이 옥수수와 수수 × 수단그라스 잡종의 생산성 및 토양특성에 미치는 영향)

  • Shin, J.S.;Lee, H.H.;Shin, D.E.;Jo, Y.M.;Jung, E.S.;Lee, J.K.;Yoon, S.H.
    • Journal of The Korean Society of Grassland and Forage Science
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    • v.19 no.4
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    • pp.333-338
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    • 1999
  • The experiment was carried out to find the effects of the application method of dairy liquid manure on productivity of silage corn(P3352) and sorghum $\times$ sudangrass hybrid(P988) and physical and chemical properties of soil during 2 years at Suwon. Crude protein content of T1(Chemical fertilizer) was highest by 6.5%, 8.9% in both forage, respectively, but total digestible nutrient(TDN) percent of T3(dairy liquid manure, basal + chemical fertilizer, topdressing) was highest by 73.8%, 59.0% in both forage, respectively. In TND yield, it was little different between T1(9.5 MT/ha) and others(8.4~9.3 MT/ha) at silage corn, but T4(chemical fertilizer at basal + dairy liquid manure at topdressing) was highest as 13.3 MT/ha at sorghum $\times$ sudangrass hybrid(p<0.05). pH of the soil after experiment was lower than that of the soil before experiment in the both forages, but soil organic matter was high at after trial than before trial. Available phosphorous and exchangeable cation were not shown the regular trend in this experiment. Based on the results of this experiment, it was not shown among different application method for silage corn (P3352), but application of chemical fertilizer at basal and liquid manure at topdressing was good for sorghum $\times$ sudangrass hybrid(P988).

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Development of the Information Delivery System for the Home Nursing Service (가정간호사업 운용을 위한 정보전달체계 개발 I (가정간호 데이터베이스 구축과 뇌졸중 환자의 가정간호 전산개발))

  • Park, J.H;Kim, M.J;Hong, K.J;Han, K.J;Park, S.A;Yung, S.N;Lee, I.S;Joh, H.;Bang, K.S
    • Journal of Home Health Care Nursing
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    • v.4
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    • pp.5-22
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    • 1997
  • The purpose of the study was to development an information delivery system for the home nursing service, to demonstrate and to evaluate the efficiency of it. The period of research conduct was from September 1996 to August 31, 1997. At the 1st stage to achieve the purpose, Firstly Assessment tool for the patients with cerebral vascular disease who have the first priority of HNS among the patients with various health problems at home was developed through literature review. Secondly, after identification of patient nursing problem by the home care nurse with the assessment tool, the patient's classification system developed by Park (1988) that was 128 nursing activities under 6 categories was used to identify the home care nurse's activities of the patient with CAV at home. The research team had several workshops with 5 clinical nurse experts to refine it. At last 110 nursing activities under 11 categories for the patients with CVA were derived. At the second stage, algorithms were developed to connect 110 nursing activities with the patient nursing problems identified by assessment tool. The computerizing process of the algorithms is as follows: These algorithms are realized with the computer program by use of the software engineering technique. The development is made by the prototyping method, which is the requirement analysis of the software specifications. The basic features of the usability, compatibility, adaptability and maintainability are taken into consideration. Particular emphasis is given to the efficient construction of the database. To enhance the database efficiency and to establish the structural cohesion, the data field is categorized with the weight of relevance to the particular disease. This approach permits the easy adaptability when numerous diseases are applied in the future. In paralleled with this, the expandability and maintainability is stressed through out the program development, which leads to the modular concept. However since the disease to be applied is increased in number as the project progress and since they are interrelated and coupled each other, the expand ability as well as maintainability should be considered with a big priority. Furthermore, since the system is to be synthesized with other medical systems in the future, these properties are very important. The prototype developed in this project is to be evaluated through the stage of system testing. There are various evaluation metrics such as cohesion, coupling and adaptability so on. But unfortunately, direct measurement of these metrics are very difficult, and accordingly, analytical and quantitative evaluations are almost impossible. Therefore, instead of the analytical evaluation, the experimental evaluation is to be applied through the test run by various users. This system testing will provide the viewpoint analysis of the user's level, and the detail and additional requirement specifications arising from user's real situation will be feedback into the system modeling. Also. the degree of freedom of the input and output will be improved, and the hardware limitation will be investigated. Upon the refining, the prototype system will be used as a design template. and will be used to develop the more extensive system. In detail. the relevant modules will be developed for the various diseases, and the module will be integrated by the macroscopic design process focusing on the inter modularity, generality of the database. and compatibility with other systems. The Home care Evaluation System is comprised of three main modules of : (1) General information on a patient, (2) General health status of a patient, and (3) Cerebrovascular disease patient. The general health status module has five sub modules of physical measurement, vitality, nursing, pharmaceutical description and emotional/cognition ability. The CVA patient module is divided into ten sub modules such as subjective sense, consciousness, memory and language pattern so on. The typical sub modules are described in appendix 3.

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The Development of Theoretical Model for Relaxation Mechanism of Sup erparamagnetic Nano Particles (초상자성 나노 입자의 자기이완 특성에 관한 이론적 연구)

  • 장용민;황문정
    • Investigative Magnetic Resonance Imaging
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    • v.7 no.1
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    • pp.39-46
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    • 2003
  • Purpose : To develop a theoretical model for magnetic relaxation behavior of the superparamagnetic nano-particle agent, which demonstrates multi-functionality such as liver- and lymp node-specificity. Based on the developed model, the computer simulation was performed to clarify the relationship between relaxation time and the applied magnetic field strength. Materials and Methods : The ultrasmall superparamagnetic iron oxide (USPIO) was encapsulated with biocompatiable polymer, to develop a relaxation model based on outsphere mechanism, which was resulting from diffusion and/or electron spin fluctuation. In addition, Brillouin function was introduced to describe the full magnetization by considering the fact that the low-field approximation, which was adapted in paramagnetic case, is no longer valid. The developed model describes therefore the T1 and T2 relaxation behavior of superparamagnetic iron oxide both in low-field and in high-field. Based on our model, the computer simulation was performed to test the relaxation behavior of superparamagnetic contrast agent over various magnetic fields using MathCad (MathCad, U.S.A.), a symbolic computation software. Results : For T1 and T2 magnetic relaxation characteristics of ultrasmall superparamagnetic iron oxide, the theoretical model showed that at low field (<1.0 Mhz), $\tau_{S1}(\tau_{S2}$, in case of T2), which is a correlation time in spectral density function, plays a major role. This suggests that realignment of nano-magnetic particles is most important at low magnetic field. On the other hand, at high field, $\tau$, which is another correlation time in spectral density function, plays a major role. Since $\tau$ is closely related to particle size, this suggests that the difference in R1 and R2 over particle sizes, at high field, is resulting not from the realignment of particles but from the particle size itself. Within normal body temperature region, the temperature dependence of T1 and T2 relaxation time showed that there is no change in T1 and T2 relaxation times at high field. Especially, T1 showed less temperature dependence compared to T2. Conclusion : We developed a theoretical model of r magnetic relaxation behavior of ultrasmall superparamagnetic iron oxide (USPIO), which was reported to show clinical multi-functionality by utilizing physical properties of nano-magnetic particle. In addition, based on the developed model, the computer simulation was performed to investigate the relationship between relaxation time of USPIO and the applied magnetic field strength.

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Development of Immediate Face Lifting Technology for Reducing Wrinkles by Using Film-Forming Agent (피막 형성제를 이용한 즉각 리프팅 기술 개발)

  • Jun, Ji hyun;Ko, Eun ah;Han, Sang Gun;Kang, Hakhee
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.44 no.3
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    • pp.211-218
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    • 2018
  • Instant face lifting cosmetics contain various film forming agents for stretching the wrinkles on the skin surface. But, most of the film-forming polymers have sticky feels. And they are easily scrubbed out when skin is rubbed on. In this study, we focused on the influence of sodium silicate that has rapid film forming effect on skin surface and immediate wrinkle reducing effect. Sodium silicate, also known as water glass or soluble glass, is a compound containing sodium oxide and silica. Sodium silicate is a white powder that is readily soluble in water, producing an alkaline solution. Sodium silicate is stable in neutral and alkaline solutions. The sodium silicate solution hardens by drying in air and rapidly forms a thin film. When the solution is applied to the skin, the fine membrane coating is formed by water evaporation and ionic bond re-formation. It also makes the strong siloxane (Si-O) bonding on the skin surface. When these fixation properties are applied to cosmetics, they can give remarkable skin tightening effect. The sodium silicate solution can provide the lifting effect by forming a film on skin at a proper concentration. But, skin irritation may be caused with too high concentration of sodium silicate. We studied a desirable range of the sodium silicate concentration and combination with other fixatives for skin care formulation that has no sticky feels and no scrubbing out phenomenon. Immediate lifting gel was developed by using sodium silicate and various thickening systems. Among of the various thickeners, aluminum magnesium silicate showed the best compatibility with sodium silicate for rapid lifting effect. This instant physical lifting gel was confirmed as a low stimulating formula by skin clinical test.

Fabrication and Characterization of Transparent Conductive Film based on Bacterial Cellulose (Bacterial cellulose를 기반으로 하는 투명전도성막의 제조 및 특성평가)

  • Yim, Eun-Chae;Kim, Seong-Jun;Kee, Chang-Doo
    • Korean Chemical Engineering Research
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    • v.51 no.6
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    • pp.766-773
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    • 2013
  • A transparent film was fabricated based on bacterial cellulose (BC), BC has excellent physical strength and stability at high temperature and it is an environmental friendly flexible material. In order to improve the conductivity, silver nanowire (AgNW) and/or graphene were introduced to the BC membrane. The aspect ratio of the AgNW synthesized in this study was 214, with a length of $15{\mu}m$ and width of 70 nm. The higher aspect ratio improved the conductivity by reducing the contact resistance. The thermal and electrical properties of 7 types of films prepared were investigated. Each film was fabricated with rectangular shape ($2mm{\times}2mm{\times}50{\mu}m$). The films were scored with a net shape by a knife, and filled with AgNW and graphene to bestow conductivity. The film filled with AgNW showed favorable electrical characteristics with a thickness of $350{\mu}m$, electron concentration of $1.53{\times}10^{19}$, electron mobility of $6.63{\times}10^5$, and resistivity of 0.28. The film filled with graphene had a thickness of $360{\mu}m$, electron concentration of $7.74{\times}10^{17}$, electron mobility of 0.17, and resistivity of 4.78. The transmittances at 550 nm were 98.1% and 80.9%, respectively. All the films were able to light LEDs bulbs although their brightness differed. A thermal stability test of the BC and PET films at $150{\pm}5^{\circ}C$ showed that the BC film was more stable, whereas the PET film was quickly banded. From these results, it was confirmed that there it is possible to fabricate new transparent conductivity films based on BC.

Effects of Dietary Crude Protein Level on Growth and Meat Quality of Korean Native Goats (사료의 조단백질 수준이 육성기 흑염소의 발육과 육질에 미치는 영향)

  • Choi, S.H.;Kim, S.W.;Park, B.Y.;Sang, B.D.;Kim, Y.K.;Myung, J.H.;Hur, S.N.
    • Journal of Animal Science and Technology
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    • v.47 no.5
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    • pp.783-788
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    • 2005
  • This study was conducted to investigate the optimal CP level in growing goat kids. Forty male goats were divided into four treatment groups fed diets containing CP 12, 14, 16, and 18% of concentrate feed, and rice straw, respectively. Results are summarized as follows. Average daily gain’s(ADG) of groups fed diets with CP 14% and CP 18% were 84.0 and 83.0g/d each, which were higher than group fed diets with CP 12% grown at 69.2g of ADG(P<0.05). Daily feed intakes of concentrate and rice straw were 590g and 45g each and there was no difference found between treatments. The amounts of feed required for body weight gain(g) were similar in the range of 7.0-7.3 for groups fed diets with CP 14%, 16% or 18%. But the group fed diets with CP 12% required somewhat more feed for gain at 8.8g. Dressing percentage of groups fed diet with CP 12% was 61.7%, which was higher than groups fed diets with CP 14% or CP 18%(P<0.05) but similar to that fed diet with CP 16%. Meat percentage from goats fed diet with CP 16% was 51.7%, which were higher than goats fed diets with CP 12% or CP 14%(P<0.05). Fat deposition of CP 12% group was higher than the other groups(P<0.05). Percentage of bone weight averaged 17.0% without any difference among treatment groups. Shear force and cooking loss, which are physical properties of goat meats, were lower in CP 16% and CP 14% groups than the other two groups. Water holding capacity of goats meats from CP 16% was higher than those from CP 18% group(P<0.05). Results from panel test showed that juiciness of meats from CP 16% group was higher than those from CP 12% group(P<0.05). Meats from CP 16% also was tested to be more tender than meats from the other groups. Results from this work suggest that the optimum crude protein level in growing goat's concentrate is 14-16% and that increase above this level seems not to improve meat production.