• 공업화학
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• 제16권6호
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• pp.760-767
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• 2005

소다석회유리 조성의 폐 유리를 발포유리의 원료로 활용하기 위하여 가수분해에 의해 수화된 폐유리를 발포시켜 발포유리의 제조를 시도하였다. 소다석회 유리 조성의 수화된 폐유리들은 판유리, 병유리 또는 그 색깔에 관계없이 발포조제로서 흑연의 량은 수화된 폐유리의 중량에 대한 중량비로 0.003, 소성온도 $925^{\circ}C$, 소성발포시간 10~20 min, 원료유리의 입도는 수화되기전의 유리의 입도로서 -325 mesh가 최적의 발포유리제조의 조건이었다. 상기의 조건하에 혼합된 폐유리의 수화유리를 발포시킨 결과 밀도 $0.2g/cm^3$이고 열전도도는 $0.05kcal/mh^{\circ}C$이 발포유리를 제조하였다.

• Animal Bioscience
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• 제35권7호
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• pp.1048-1058
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• 2022

Objective: The present study was to investigate the extraction conditions of dietary fiber from dried cassava pulp (DCP) and cassava distiller's dried grains (CDG) under different NaOH concentrations, and the Fourier transform infrared (FTIR) was used to determine the dietary fiber components. Methods: The dried samples (DCP and CDG) were treated with various concentrations of NaOH at levels of 2%, 4%, 6%, and 8% using a completely randomized design with 4 replications of each. After extraction, the residual DCP and CDG dietary fiber were dried in a hot air oven at 55℃ to 60℃. Finally, the oven dried extracted dietary fiber was powdered to a particle size of 1 mm. Both extracted dietary fibers were analyzed for their chemical composition and determined by FTIR. Results: The DCP and CDG treated with NaOH linearly or quadratically or cubically (p<0.05) increased the total dietary fiber (TDF) and insoluble fiber (IDF). The optimal conditions for extracting dietary fiber from DCP and CDG were under treatment with 6% and 4% NaOH, respectively, as these conditions yielded the highest TDF and IDF contents. These results were associated with the FTIR spectra integration for a semi-quantitative analysis, which obtained the highest cellulose content in dietary fiber extracted from DCP and CDG with 6% and 4% NaOH solution, respectively. The principal component analysis illustrated clear separation of spectral distribution in cassava pulp extracted dietary fiber (DFCP) and cassava distiller's dried grains extracted dietary fiber (DFCDG) when treated with 6% and 4% NaOH, respectively. Conclusion: The optimal conditions for the extraction of dietary fiber from DCP and CDG were treatment with 6% and 4% NaOH solution, respectively. In addition, FTIR spectroscopy proved itself to be a powerful tool for fiber identification.

• Journal of Animal Science and Technology
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• 제63권6호
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• pp.1433-1442
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• 2021

In this study, Saccharomyces cerevisiae culture fluid (SCCF) has been added to a diet of lactating dairy cows to attempt to improve the ruminal fermentation and potentially increase the dry matter intake (DMI) and milk yield. This study was conducted to investigate the effects of SCCF on the milk yield and blood biochemistry in lactating cows during the summer. Twenty-four Holstein dairy cows were randomly assigned to one of four treatments: (1) total mixed ration (TMR-1) (Control); (2) TMR-1 supplemented with SCCF (T1); (3) TMR-2 (containing alfalfa hay) (T2); and (4) TMR-2 supplemented with SCCF (T3). SCCF (5 ml/head, 2.0×10⁷ CFU/mL) was mixed with TMRs daily before feeding to dairy cows. The mean daily temperature-humidity index (THI) during this trial was 76.92 ± 0.51 on average and ranged from 73.04 to 81.19. For particle size distribution, TMR-2 had a lower >19 mm fraction and a higher 8-9 mm fraction than TMR-1 (p < 0.05). The type of TMR did not influence the DMI, body weight (BW), milk yield and composition, or blood metabolites. The milk yield and composition were not affected by the SCCF supplementation, but somatic cell counts were reduced by feeding SCCF (p < 0.05). Feeding SCCF significantly increased the DMI but did not affect the milk yield of dairy cows. The NEFA concentration was slightly decreased compared to that in the control and T2 groups without SCCF. Feeding a yeast culture of S. cerevisiae may improve the feed intake, milk quality and energy balance of dairy cows under heat stress.

• 한국가스학회지
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• 제26권2호
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• pp.1-8
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• 2022

본 연구에서는 탄산염암 저류층에서 활용 가능한 GPTMS((3-Glycidoxypropyl)trimethoxysilane)-SiO₂ 나노유체를 제조하고 주입 효과를 분석하였다. 표면개질에 따른 나노입자의 구조적 변화를 확인하기 위해 푸리에변환적외선분광(Fourier transform infrared spectroscopy, FTIR) 분석을 수행했으며, 0.5 mmol/g 이상의 GPTMS 농도에서 실리카 입자의 표면개질을 의미하는 2,950 cm^-1의 C-H 신축 진동(C-H stretching vibration)을 확인하였다. 또한, 친유성 상태로 에이징된 석회석과 백운석을 대상으로 나노입자의 농도와 주입률에 따른 GPTMS-SiO₂ 나노유체의 코어유동 실험을 수행하였다. 나노유체 주입에 따라 최대 18.9%의 오일이 추가로 회수되었으며, 암석의 접촉각과 투과도 변화를 확인할 수 있었다. 이는 나노입자가 탄산염암 표면에 흡착됨에 따라 습윤도를 개선함과 동시에 공극에 영향을 준다는 것을 의미한다. 따라서, 제조된 나노유체는 탄산염암 저류층을 대상으로 한 석유회수증진의 주입유체로 사용될 수 있으며 습윤도, 투과도 변화와 같은 유체 유동물성 개선에 활용될 것으로 기대된다.

• 한국축산식품학회지
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• 제44권3호
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• pp.723-737
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• 2024

Yeast protein can be a nutritionally suitable auxiliary protein source in livestock food. The breakdown of proteins and thereby generating high-quality peptide, typically provides nutritional benefits. Enzyme hydrolysis has been effectively uesed to generate peptides; however, studies on the potential applications of different types of enzymes to produce yeast protein hydrolysates remain limited. This study investigated the effects of endo- (alcalase and neutrase) and exotype (flavourzyme and prozyme 2000P) enzyme treatments on yeast protein. Endotype enzymes facilitate a higher hydrolysis efficiency in yeast proteins than exotype enzymes. The highest degree of hydrolysis was observed for the protein treated with neutrase, which was followed by alcalase, prozyme 2000P, and flavourzyme. Furthermore, endotype enzyme treated proteins exhibited higher solubility than their exotype counterparts. Notably, the more uniform particle size distribution was observed in endotype treated yeast protein. Moreover, compared with the original yeast protein, the enzymatic protein hydrolysates possessed a higher content of β-sheets structures, indicating their higher structural stability. Regardless of enzyme type, enzyme treated protein possessed a higher total free amino acid content including essential amino acids. Therefore, this study provides significant insights into the production of protein hydrolysates as an alternative protein material.

• Asian-Australasian Journal of Animal Sciences
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• 제16권11호
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• pp.1610-1613
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• 2003

The aim of the experiment was to study the changes in the activities of various rumen fibre degrading enzymes due to the feeding of chemically treated mustard (Brassica campestris) straw in sheep. Mustard straw (MS) (<5 cm particle size) was treated either with urea (4% (w/w), or with 2% sodium hydroxide (NaOH), or with alkaline hydrogen peroxide (2% NaOH and 1.5% hydrogen peroxide ($H_2O_2$)) and/or supplemented with 2% (w/w) urea. Seven maintenance type rations were prepared using MS (70 parts) with molasses (5 parts) and concentrate (25 parts). They were untreated MS (CMS), urea treated MS (UMS), urea supplemented MS (MSUS), alkali treated MS (AMS), alkali treated and urea supplemented MS (AMS-US), alkali $H_2O_2$ treated MS (AHMS) and alkali $H_2O_2$ treated and urea supplemented MS (AHMS-US). They were then compressed into a complete feed block with the help of block making machine. Forty two male hoggets of Malpura breed sheep were equally distributed into each treatment group and (were) offered feed and water ad libitum. At the end of 21 days of feeding trial, rumen liquor was collected through stomach tube from three animals in each group at 0 h, 4 h, 8 h, 12 h of post feeding. Results showed that the level of enzyme varied from 8.52 to 11.12, 40.85 to 50.37, 3.22 to 3.78, 2.09 to 2.77 and 31.44 to 44.24 units/100 ml SRL respectively for carboxymethyl cellulase (CMCase), $\alpha$-amylase, microcrystalline cellulase (MCCase), filter paper (FP) degrading enzyme and $\alpha$-glucosidase. Processing of MS affected the enzyme activities, in a way, that NaOH and AHP treatment significantly reduced CMCase and FP degrading enzyme. The effect of urea treatment showed an increase in the activity of MCCase and $\alpha$-glucosidase. But the supplementation of urea increased the activity of CMCase, FP degrading enzyme and $\alpha$-glucosidase. The CMCase, $\alpha$-amylase, $\alpha$-glucosidase activities were highest at 4hr whereas MCCase and FP degrading enzyme had maximum activities at 12 h post feeding Results suggested that MS might need longer time in the rumen for its effective degradation.

• Asian-Australasian Journal of Animal Sciences
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• 제29권3호
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• pp.444-454
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• 2016

This study was designed to examine the characteristics of sawdust and cocopeat bedding materials, including physicochemical properties (Exp. I) and on-farm trial (Exp. II). In Exp. I, the proportion of particle size was in the order of sawdust>cocopeat India>cocopeat Vietnam (p<0.05), and cocopeat contained higher proportion of small particles ($250{\mu}m$+below $250{\mu}m$) than sawdust, causing a dust production problem. Bulk density was cocopeat India>cocopeat Vietnam>sawdust (p<0.05), thus cocopeat treatments showed 4.4 times higher bedding cost than sawdust. The water absorption rates were 702.0% in cocopeat India, 678.3% in cocopeat Vietnam, and 444.0% in sawdust, showing cocopeat had approximately 1.5 times higher water absorption rate than sawdust. Moisture evaporation rates after 12 h of air blowing (2.00 m/s) were higher (p<0.05) in cocopeat Vietnam (80.4%) than sawdust (71.2%) and cocopeat India (72.8%). In vitro ammonia emissions were higher (p<0.05) in sawdust ($2.71mg/m^2/h$) than cocopeat India ($1.59mg/m^2/h$) and Vietnam ($1.22mg/m^2/h$), and total ammonia emissions were higher (p<0.05) in sawdust ($37.02mg/m^2$) than cocopeat India ($22.51mg/m^2$) and Vietnam ($13.60mg/m^2$). In Exp. II, an on-farm trial was conducted with 48 Hanwoo cattle in 16 pens using the same bedding materials as in Exp. I, with fan (blowing 2.00 m/s) and no fan treatments, and feed bunk side (FB) and water supply side (WS) within a pen (4.5 m, $width{\times}9.0m$, length). Beddings were replaced with fresh bedding materials when moisture concentrations were over 65%. No interactions among treatments were detected for moisture concentration and increment rates, and ammonia concentrations, but a significant effect was observed (p<0.01) for each of the treatments. Both concentrations and increment rate of moisture were higher (p<0.01) in the beddings without fan than with fan. Moisture concentrations and increment rate within a pen were also higher (p<0.01) in FB than WS. Thus, the whole no-fan-FB and sawdust-fan-FB were replaced with fresh bedding material between 4 to 5 experimental weeks. The ammonia concentrations and pH of beddings were not significantly different among treatments. Therefore, using cocopeat bedding with a blowing fan can extend twice the bedding utilization period, and WS within a pen showed twice the bedding-life compared to FB. Despite the outstanding characteristics of cocopeat compared with sawdust, using cocopeat as an alternative for sawdust bedding is not recommended for cattle management, considering it has 4.4 times higher bedding cost and a dust production problem.

• 청정기술
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• 제13권1호
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• pp.34-45
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• 2007

고지혈증 치료제로 잘 알려져 있는 난용성 약물인 심바스타틴(simvastatin)을 대상으로 디클로로메탄을 용매로 사용하고 초임계 이산화탄소를 역용매로 사용하는 초임계 역용매 재결정법에 의해 약물 미세입자를 제조할 때, 운전 조건을 설정하는데 활용될 수 있는 가이드 라인을 제공하기 위하여 simvastatin/디클로로메탄/초임계 이산화탄소 3성분계 혼합물의 상거동을 연구하였다. 가변부피 투시 셀이 장착된 고압 상평형 장치를 사용하여 여러 가지 조건에서 3성분계 혼합물의 구름점(cloud point)을 측정함으로서 디클로로메탄과 초임계 이산화탄소의 혼합용매에서 simvastatin의 용해도를 온도, 압력, 용매 조성의 함수로 결정하였다. 주어진 온도에서 Simvastatin 약물의 용해도는 디클로로메탄의 조성과 압력이 증가할수록 온도가 감소할수록 증가하였다. 상거동 데이터를 바탕으로 교반기가 설치된 실린더 모양의 고압 용기에서 초임계 역용매 재결정 공정을 이용하여 simvastatin 약물을 미세입자로 제조하는 연구를 수행하였다. 운전 조건인 압력 ($8{\sim}12\;MPa$), 온도(303.15 K, 313.15 K), 이산화탄소 공급 속도, 교반 속도 (최대 3,000 rpm)를 변화시키면서 simvastatin 미세입자를 제조함으로써 재결정되는 약물 입자의 크기와 모양에 미치는 공정 변수들의 영향을 관찰하였다.

• 에너지공학
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• 제13권4호
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• pp.281-290
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• 2004

석탄 가스화기에서 1000시간 이상 사용된 Cr$_2$O$_3$-Al$_2$O$_3$-ZrO$_2$ 내화물의 결정구조, 화학성분, 미세구조를 분석하여 석탄 슬래그에 의한 화학적 침식 메카니즘을 규명하였다 크로미아 내화물의 침식은 슬래그의 FeO와 $Al_2$O$_3$이 Cr$_2$O$_3$과 반응하며 일어나는 것으로 추정된다. 1차적으로 내화물의 슬래그 접촉면에서 슬래그의 FeO와 Cr$_2$O$_3$가 반응하여 FeCr$_2$O$_4$를 형성한다. 슬래그의 FeO가 모두 소모된 후 슬래그의 $Al_2$O$_3$이 Cr$_2$O$_3$ 입자와 반응하여 (Al, Cr)$_2$O$_3$를 형성하고, (Al, Cr)$_2$O$_3$상은 가장자리로부터 깨어져 미세한 입자를 형성한다. Cr$_2$O$_3$의 침식정도는 입자 크기와 치밀도에 따라 달라지며, 입자가 클수록, 치밀도가 높을수록 내침성이 증가하였다. ZrO$_2$는 화학적 성분의 변화 없었으나 슬래그 접촉면 부근에서 상 경계의 굴곡이 심해지거나 입자가 절단되는 물리적 침식의 영향을 받는다. 슬래그의 침투도는 일반적으로 석탄 주입구에서 아래로 내려갈수록 증가하나 슬래그 tap에서는 감소하였다.

• 멤브레인
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• 제18권1호
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• pp.65-74
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• 2008

자연산 유기물과 미세 입자는 분리막을 이용한 수처리 공정에서 반드시 제거되어야 하는 주요한 물질이다. 특히 휴믹물질은 막오염을 일으키는 자연산 유기물의 대표적인 물질로 알려져 있어 막여과 정수처리와 관련된 많은 연구에서 정수 원수를 모사하기 위해 이용되고 있다. 본 연구에서는 휴믹산 용액과 자연수의 한외여과시 막여과 및 세척 특성을 비교 분석하여 분리막 모듈의 실제 정수 원수 적용시 휴믹산 용액을 이용한 모사수가 가지는 대표성을 검토하고자 하였다. 정수원수의 막투과도는 5 mg/L 휴믹산 용액의 여과와 거의 같은 양상을 보였으나 유기물 및 탁도 제거율 측면에서 차이를 보였다. 용존성 유기물의 제거율은 휴믹산 용액에 비해 자연수의 제거율이 아주 낮으며 자연수 내에 존재하는 유기물은 분리막에 의해 거의 제거되지 않음을 알 수 있었다. 모사수의 제거율이 상대적으로 높게 나타난 이유는 유입수 내 유기물의 분자량 분포와 $UV_{254}$ 및 SUVA 값으로부터 휴믹산 용액 내 유기물의 크기 배제 및 소수성 흡착 때문인 것으로 사료된다. 미세입자 제거의 경우 입자 분포에 있어서 상대적으로 작은 크기의 카올린을 함유한 모사수가 자연수에 비해 한외여과 처리수의 탁도가 더 낮게 나타났다. 이는 입자 크기 자체보다는 입자의 형태가 분리막에 의한 입자 제거에 영향을 미치는 것으로 추정된다. 또한 화학세정을 통한 막성능 회복률의 경우 비슷한 막투과도를 보이며 오염을 일으킨 경우에도 모사수가 자연수에 비해 다소 높은 회복률을 보였고, 이 또한 모사수의 한계를 드러낸다고 하겠다.