• Title/Summary/Keyword: chemical analysis tests

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Simulation analysis on the separation characteristics and motion behavior of particles in a hydrocyclone

  • Xu, Yanxia;Tang, Bo;Song, Xingfu;Sun, Ze;Yu, Jianguo
    • Korean Journal of Chemical Engineering
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    • v.35 no.12
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    • pp.2355-2364
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    • 2018
  • We evaluated the effect of particle size and associated dynamics on a hydrocyclone separation process in order to understand the movement of the particle trajectories inside the hydrocyclone via numerical analysis, with particles of acid hydrolysis residues discharged in $TiO_2$ production via the sulfate method as a case study. The values obtained from the numerical simulation were successfully compared with those from experimental tests in the literature, allowing a description of the dynamics of the particles, their acting forces, and their relevant properties together with separation efficiency. The results showed that particle motion is jointly controlled by the drag force, the pressure gradient force and the centrifugal force. With increasing particle size, the influence of the drag force is weakened, whereas that of the centrifugal force and pressure gradient is strengthened. Factors including particle density, slurry viscosity, and inlet slurry flow rate also contribute to a clear and useful understanding of particle motion behavior in the hydrocyclone as a method for improving the separation efficiency.

Study on the Sun Screen Test Method using Elipsometer (분광타원해석기를 이용한 자외선 차단제의 평가방법 연구)

  • Kim, Joon-Woo;Lee, Jong-Soo;Lee, Ji-Hye;Choung, Suk-Jin
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.37 no.2
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    • pp.137-141
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    • 2011
  • Sunscreen is divided into the organic agent of UV absorption and inorganic agent of reflection. These are evaluated by sun protection factor (SPF) in-vivo test requiring high cost and time, while in-vitro tests are adopted commonly because of short test time, easy result collection. Generally, test method of SPF use SPF 290a by UV-vis spectrometer. The evaluate by SPF 290 has low reproducibility. Although analysis using UV-vis spectrometer has high reproducibility, it is hard to separated results of transmission, adsorption, and reflection. In this study, suggested method of elipsometer has some merit such as high reproducibility, easy separation of transmission/adsorption/re- flection, analysis using various incident angle. We tested the validity of elipsometer for SPF measurement, using commercially available sun-block (SPF 50).

Analysis of the Apparent Specific Gravity for Type-3 Dry Chemical Powder with the Changes in the Internal Pressure of Dry Chemical Extinguisher (분말소화기의 내부압력 변화에 따른 제3종 분말소화약제의 겉보기비중 실험 분석)

  • Ju-Dal, Son;Seo-young, Kim;Ha-sung, Kong
    • The Journal of the Convergence on Culture Technology
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    • v.9 no.3
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    • pp.607-617
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    • 2023
  • This study aims to analyze whether the performance of the fire extinguisher meets the criteria for the apparent specific gravity property test by calculating the change in internal pressure and the use period of the fire extinguisher as a new one with 5 years, recycled one with 5 years, a new one with 10 years, and a new one with 13 years, respectively. As a result of the experiment, when the internal pressure of the fire extinguisher was 0%, the first, second, and third arithmetic mean analysis of the dry chemical extinguisher according to the use period was found to be condemned. When the internal pressure of the fire extinguisher was 50%, it was measured as 130 ml in sample 12-08-new and analyzed as unsuitable. Also, sample 09-09-new of a new dry chemical extinguisher with 13 elapsed years measured 145ml, which was found inappropriate. All other dry chemical extinguishers were analyzed to be suitable. All were noted suitable when having normal internal pressure of the fire extinguisher, except for sample 09-06 of a new dry chemical extinguisher with 13 elapsed years, which was determined to be unsuitable caused by measuring as 131 ml for experimental value. As a result of experiments, some of the apparent specific gravity tests of dry chemical extinguishers from 10 years to 13 years have found that they are unsuitable for the performance of the fire extinguishers due to the massive phenomenon. Accordingly, it is necessary to reduce the endurance period of dry chemical extinguishers from 10 years to 7 years.

Effect of Reinforcing Fiber on Mechanical Properties and Chemical Resistance of Porous Concrete with Hwang-toh (황토를 포함한 다공성 식생콘크리트의 역학적 특성 및 내약품성에 미치는 보강섬유의 효과)

  • Lee, Jin-Hyung;Park, Chan-Gi;Park, Jong-Sik
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.31 no.2A
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    • pp.105-113
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    • 2011
  • This study evaluated the effects of fibers on the mechanical properties and chemical solution resistance of porous concrete with fiber type (jute, pulp, PVA and nylon fiber) and fiber volume fraction (0.0%, 0.1%, 0.2%, 0.3%). The tests that were carried out to analysis the properties of porous concrete included compressive strength, void ratio, pH value, and chemical solution exposure with varying type and volume fraction of fiber were conducted. The type and volume fraction of fiber also affected the void ratio, compressive strength, flexural strength and chemical solution exposure. Increased volume fractions of fiber resulted in improved properties of the compressive strength, flexural strength and void ratio. However, the difference between the measured pH value and chemical resistance of porous concrete with fiber type and volume fraction was not significant.

The Effect of Y at Ni-YSZ Catalysts for the Application to the Process of Methane Chemical-Looping Reforming (메탄을 이용한 매체 순환 개질 시스템을 위한 Ni-YSZ 촉매에서의 Y에 따른 촉매 반응 특성 연구)

  • KIM, HEESEON;JEON, YUKWON;HWANG, JUSOON;SONG, SOONHO;SHUL, YONG-GUN
    • Transactions of the Korean hydrogen and new energy society
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    • v.26 no.6
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    • pp.516-523
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    • 2015
  • Nickel based oxygen transfer materials supported on two different YSZs were tested to evaluate their performance in methane chemical-looping reforming. The oxygen transfer materials of YSZs were selected with different amount of the doped yittrium in the $ZrO_2$ structure. The yittrium of 8 mol% stabilized the zirconia oxide to a cubic structure compare to the 3 mol% doping, which is known to be a good for oxygen transfer. Various nickel amounts (16wt.%, 32wt.%, 48wt.%) were loaded on the selected supports. The nickel amount of 32% shows the optimized catalyst structure with good physical properties and reducibility from the XRD, BET and H2-TPR analysis, especially when the support of 8YSZ was used. From the methane chemical-looping reforming, hydrogen was produced by methane decomposition catalyzed by Ni on both YSZs. Comparing two YSZ supports of 3YSZ and 8YSZ during the cycling tests, the catalyst with 8YSZ (Ni 32%) exhibits not only the higher methane conversion and hydrogen production but also a faster reaction rate reaching to the stable point.

Acute and Subchronic Inhalation Toxicity Evaluation of Methyl Formate in Rats (Methyl formate의 랫드를 이용한 급성 및 아만성 흡입독성 평가)

  • Kim, Hyeon-Yeong;Lee, Sung-Bae;Han, Jeong-Hee;Kang, Min-Gu;Yang, Jeong-Sun
    • Environmental Analysis Health and Toxicology
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    • v.25 no.2
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    • pp.131-143
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    • 2010
  • We performed the tests of acute and subchronic inhalation toxicity of methyl formate, which has limited toxicological data in spite of its widespread use and enhanced hazard consequent on its high volatility. The median lethal concentration ($LC_{50}$) was evaluated to be above 5,000ppm(12.27 mg/L). In the test with subchronic inhalation, there are no deaths, but with reduction of body weight, food intake, organ weight by exposure to 400 (0.98 mg/L) and 1,600 (3.92 mg/L) ppm, dose-dependently. There were statistical differences in some hematological and blood biochemical parameters as compared to control (e.g. neutrophile and lymphocyte in the 1,600 ppm group, calcium and A/G in 1,600 ppm group). Methyl formate under the exposure of 1,600 ppm showed the respiratory findings with nasal, it was confirmed that the chemical has respiratory hazard with 1,600 ppm inhalation exposure, induces nasal epithelial atrophy, olfactory cell degeneration/regeneration and the contraction of olfactory cells, etc. According to the notification with Ministry of Labor (No. 2009-68) for classification, labeling and MSDS of chemicals, it is suggested for methyl formate to be classified as category 4 in acute (10.0$4\leq20.0$ mg/L), category 2 (0.2$\leq$1.0 mg/L/6h, 90 days) in specific target organ-repeated exposure.

Photopolymerization and Properties of PCL-Based Biodegradable Molecularly Imprinted Polymers (PCL 기반 생분해성 분자 날인 고분자의 광중합 및 물성)

  • Kim, Sun-Hui;Lee, Kyung-Soo;Kim, Yong-Hoon;Choi, Woo-Jin;Kim, Beom-Soo;Kim, Eung-Kook;Kim, Dae-Su
    • Polymer(Korea)
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    • v.31 no.2
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    • pp.153-159
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    • 2007
  • Biodegradable molecularly imprinted polymers (MIPs) can be applied in the biomedical area of biosensors, drug delivery, etc. Therefore, in this study, biodegradable theophylline MIPs were synthesized via photopolymerization using a poly $(\varepsilon-caprolactone)$ (PCL) macromer as a cross-linker and their physical properties were investigated. The yield for the synthesis of the PCL macromer with terminal acrylate groups was ca. 78 mol%. The products were characterized by the combination of FT-IR and $^1H-NMR$ spectroscopic analyses. UV/Visible spectroscopic analysis for removing and rebinding theophylline was performed by monitoring the theophylline concentration in the solution. In vitro biodegradation tests of the theophylline MIPs performed in phosphate buffered saline (PBS) solution at $37^{\circ}C$ showed good biodegradability of the MIPs.

Development of the Highly Dispersed Palladium-Nickel Catalysts for Catalytic Partial Oxidation of Methane (메탄 부분산화 반응을 위한 고분산된 팔라듐-니켈 촉매 합성 및 반응)

  • Lee, Seunghyun;Jeon, Jonghyun;Kim, Juchan;Ha, Kyoung-Su
    • Korean Chemical Engineering Research
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    • v.59 no.2
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    • pp.269-275
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    • 2021
  • In this study, ordered mesoporous silica-supported Ni catalysts were prepared for catalytic partial oxidation of methane (CPOM) by using electroless nickel plating method. Unlike conventionally impregnated catalysts, the electrolessly-plated nickel catalyst showed that nickel was highly dispersed and formed stably on silica-supported surface. It was verified by TEM-EDS analysis. During the activity tests, the electrolessly-plated nickel was barely sintered and the amount of carbon deposition was very small. Consequently, the catalyst was far less deactivated, while the sintering was significantly observed in the cases of the catalysts prepared by the conventional impregnation method. Regarding the palladium-promoted catalysts, the reducibility of nickel was increased, and the reaction performances were enhanced in terms of CH4 conversion and H2/CO ratio of produced syngas.

Post buckling mechanics and strength of cold-formed steel columns exhibiting Local-Distortional interaction mode failure

  • Muthuraj, Hareesh;Sekar, S.K.;Mahendran, Mahen;Deepak, O.P.
    • Structural Engineering and Mechanics
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    • v.64 no.5
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    • pp.621-640
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    • 2017
  • This paper reports the numerical investigation conducted to study the influence of Local-Distortional (L-D) interaction mode buckling on post buckling strength erosion in fixed ended lipped channel cold formed steel columns. This investigation comprises of 81 column sections with various geometries and yield stresses that are carefully chosen to cover wide range of strength related parametric ratios like (i) distortional to local critical buckling stress ratio ($0.91{\leq}F_{CRD}/F_{CRL}{\leq}4.05$) (ii) non dimensional local slenderness ratio ($0.88{\leq}{\lambda}_L{\leq}3.54$) (iii) non-dimensional distortional slenderness ratio ($0.68{\leq}{\lambda}_D{\leq}3.23$) and (iv) yield to non-critical buckling stress ratio (0.45 to 10.4). The numerical investigation is carried out by conducting linear and non-linear shell finite element analysis (SFEA) using ABAQUS software. The non-linear SFEA includes both geometry and material non-linearity. The numerical results obtained are deeply analysed to understand the post buckling mechanics, failure modes and ultimate strength that are influenced by L-D interaction with respect to strength related parametric ratios. The ultimate strength data obtained from numerical analysis are compared with (i) the experimental tests data concerning L-D interaction mode buckling reported by other researchers (ii) column strength predicted by Direct Strength Method (DSM) column strength curves for local and distortional buckling specified in AISI S-100 (iii) strength predicted by available DSM based approaches that includes L-D interaction mode failure. The role of flange width to web depth ratio on post buckling strength erosion is reported. Then the paper concludes with merits and limitations of codified DSM and available DSM based approaches on accurate failure strength prediction.

BEEF MEAT TRACEABILITY. CAN NIRS COULD HELP\ulcorner

  • Cozzolino, D.
    • Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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    • 2001.06a
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    • pp.1246-1246
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    • 2001
  • The quality of meat is highly variable in many properties. This variability originates from both animal production and meat processing. At the pre-slaughter stage, animal factors such as breed, sex, age contribute to this variability. Environmental factors include feeding, rearing, transport and conditions just before slaughter (Hildrum et al., 1995). Meat can be presented in a variety of forms, each offering different opportunities for adulteration and contamination. This has imposed great pressure on the food manufacturing industry to guarantee the safety of meat. Tissue and muscle speciation of flesh foods, as well as speciation of animal derived by-products fed to all classes of domestic animals, are now perhaps the most important uncertainty which the food industry must resolve to allay consumer concern. Recently, there is a demand for rapid and low cost methods of direct quality measurements in both food and food ingredients (including high performance liquid chromatography (HPLC), thin layer chromatography (TLC), enzymatic and inmunological tests (e.g. ELISA test) and physical tests) to establish their authenticity and hence guarantee the quality of products manufactured for consumers (Holland et al., 1998). The use of Near Infrared Reflectance Spectroscopy (NIRS) for the rapid, precise and non-destructive analysis of a wide range of organic materials has been comprehensively documented (Osborne et at., 1993). Most of the established methods have involved the development of NIRS calibrations for the quantitative prediction of composition in meat (Ben-Gera and Norris, 1968; Lanza, 1983; Clark and Short, 1994). This was a rational strategy to pursue during the initial stages of its application, given the type of equipment available, the state of development of the emerging discipline of chemometrics and the overwhelming commercial interest in solving such problems (Downey, 1994). One of the advantages of NIRS technology is not only to assess chemical structures through the analysis of the molecular bonds in the near infrared spectrum, but also to build an optical model characteristic of the sample which behaves like the “finger print” of the sample. This opens the possibility of using spectra to determine complex attributes of organic structures, which are related to molecular chromophores, organoleptic scores and sensory characteristics (Hildrum et al., 1994, 1995; Park et al., 1998). In addition, the application of statistical packages like principal component or discriminant analysis provides the possibility to understand the optical properties of the sample and make a classification without the chemical information. The objectives of this present work were: (1) to examine two methods of sample presentation to the instrument (intact and minced) and (2) to explore the use of principal component analysis (PCA) and Soft Independent Modelling of class Analogy (SIMCA) to classify muscles by quality attributes. Seventy-eight (n: 78) beef muscles (m. longissimus dorsi) from Hereford breed of cattle were used. The samples were scanned in a NIRS monochromator instrument (NIR Systems 6500, Silver Spring, MD, USA) in reflectance mode (log 1/R). Both intact and minced presentation to the instrument were explored. Qualitative analysis of optical information through PCA and SIMCA analysis showed differences in muscles resulting from two different feeding systems.

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