• Advances in concrete construction
• /
• 제11권4호
• /
• pp.315-321
• /
• 2021

In this article, an analytical solution of the dynamical behavior in an orthotropic non-homogeneity elastic material using for elastodynamics equations is investigated. The effects of the magnetic field, the initial stress, and the non-homogeneity on the radial displacement and the corresponding stresses in an orthotropic material are investigated. The analytical solution for the elastodynamic equations has solved regarding displacements. The variation of the stresses, the displacement, and the perturbation magnetic field have shown graphically. Comparisons are made with the previous results in the absence of the magnetic field, the initial stress, and the non-homogeneity. The present study has engineering applications in the fields of geophysical physics, structural elements, plasma physics, and the corresponding measurement techniques of magneto-elasticity.

• 한국강구조학회 논문집
• /
• 제28권3호
• /
• pp.173-183
• /
• 2016

본 연구에서는 HSA800 강재의 7종의 각종 시험을 실시하여 다양한 소재특성을 확인하였으며, 강도에 대한 균질성의 정량적 기준을 제안하였다. 또한 HSA800 강재가 강도에 대한 균질성의 기준을 만족하는지 검토하였다. 시험결과 HSA800 강재의 1/4지점의 소재 특성은 KS를 만족하며, 우수한 방향성, 저온에서의 내충격성이 나타났다. 또한, 제안한 강재의 강도에 대한 균질성의 기준을 만족하였다. 그러나, 마이크로조직시험 결과 2/4 지점에서 일부의 경우 조직이 뭉쳐있는 형태로 확인되어 주의가 요망된다.

• Structural Engineering and Mechanics
• /
• 제55권4호
• /
• pp.871-884
• /
• 2015

In the present study, separate and combined effects of rotary inertia, shear deformation and material non-homogeneity (MNH) on the values of natural frequencies of the simply supported beam are examined. MNH is characterized considering the parabolic variations of the Young's modulus and density along the thickness direction of the beam, while the value of Poisson's ratio is assumed to remain constant. At first, the equation of the motion including the effects of the rotary inertia, shear deformation and MNH is provided. Then the solutions including frequencies of the first three modes for various combinations of the parameters of the MNH, depth to length ratios, and shear corrections factors are reported. To show the accuracy of the present results, two comparisons are carried out and good agreements are found.

• 한국환경과학회지
• /
• 제28권11호
• /
• pp.1033-1040
• /
• 2019

The National Environmental Specimen Bank (NESB) has set up a plan to develop reference materials in the facility for assuring analytical quality and validating analytical methods for its monitoring samples. Some of the crucial characteristics that reference materials must consist of are homogeneity and stability of both intra and inter-bottles. In this study, we examined the homogeneity and stability of cryogenically-milled muscle samples, from Common Carp (Cyprinus carpio) for total mercury. Homogeneity was tested using ANOVA analysis and regression analysis was used to test short-term stability. The variations of total mercury concentration did not significantly differ between the intra and the inter-bottle (F=0.8, p=0.37). Additionally, relative standard deviation of the total mercury concentration showed low values (2.28%). For the short-term stability test, total mercury variations were not statistically significant as demonstrated by the result of the regression analysis (F ratio = 3.11, p = 0.18). This suggests that the cryogenic-milling process has statistically proven the degree of homogeneity and short-term stability for samples of carp muscles in the chemical analysis for total mercury.

• Mass Spectrometry Letters
• /
• 제14권4호
• /
• pp.166-172
• /
• 2023

The utilization of methyl 2-aminobenzoate as a biocide and pesticide has raised concerns regarding its potential toxicity. To assess its safety, it is crucial to determine its quantity and related toxicity using reference materials (RMs) or certified reference materials (CRMs). As an RM and CRM containing methyl 2-aminobenzoate within a biocidal product matrix is currently unavailable, this study aimed to produce a high-quality RM containing methyl 2-aminobenzoate, ensuring its homogeneity and stability, following the ISO Guide 35 and ISO 17034. The study determined that the produced RM exhibited homogeneity, as indicated by a calculated F-value (1.91) smaller than the critical F-value (3.02). In the assessment of isochronous short-term stability, the slope of the linear regression for the RM showed no statistically significant difference from zero when stored at temperatures of 4, 18, and 60 ℃ for 4 weeks. Regarding classical long-term stability, the RM demonstrated sustained stability over the course of one year when stored at 4 ℃. This study has successfully developed an RM for monitoring methyl 2-aminobenzoate in biocides and pesticides. Its quality underwent rigorous evaluation, confirming both homogeneity and stability.

• Geomechanics and Engineering
• /
• 제25권4호
• /
• pp.331-339
• /
• 2021

In this work, an analytical solution is provided for the dynamical response of an orthotropic non-homogeneous elastic material. The present study has engineering applications in the fields of geophysical physics, structural elements, plasma physics, and the corresponding measurement techniques of magneto-elasticity. The analytical performances for the elastodynamic equations has been solved regarding displacements. The influences of the rotation, the magnetic field, the non-homogeneity based radial displacement and the corresponding stresses in an orthotropic material are investigated. The variations of the stresses, the displacement, and the perturbation magnetic field have been illustrated. The comparisons is performed using the previous solutions in the magnetic field absence, the non-homogeneity and the rotation.

• 한국환경농학회지
• /
• 제35권3호
• /
• pp.223-233
• /
• 2016

BACKGROUND: This study was to develop a analytical reference material including twenty pesticides in tomato. To use it for proficiency test, the suitability of homogeneity, storage stability, assigned values and uncertainty for analytical reference material were important.METHODS AND RESULTS: In order to develop a analytical reference material of tomato for multi-residue analysis of pesticides, twenty-pesticides were treated in tomato and the samples were frozen and homogenized. The homogeneity, stability, assigned value and uncertainty were calculated according to the requirements of the KS A ISO Guide 35, KS Q ISO 13528 and EURL-PT protocol. The values of the within-bottle standard variation(s_wb) and the between-bottle standard variation(s_bb) were 0.9~6.5% of assigned value and the uncertainty(u*_bb) due to inhomogeneity was also calculated as 0.6~1.9% for all pesticides. This indicated that it was satisfactory to be used as a analytical reference material. The storage stabilities of twenty-pesticides at room temperature and freezing conditions were assessed according to the requirement of the KS Q ISO Guide 35. All pesticides were stable at room temperature (20~30℃) for 8 days and freezing (-20℃) for 23 days.CONCLUSION: The feasibility of analytical reference material for pesticide multi-residue analysis in a tomato matrix was investigated. Homogeneity of within/between-bottle, uncertainty and stabilities at room temperature and freezing condition were satisfactory for a use of proficiency test and quality control. From these results, a analytical reference material would be applicable to monitor the proficiency test of pesticide analysis organizations to improve the reliability and consistency.

• Agricultural and Biosystems Engineering
• /
• 제1권1호
• /
• pp.49-53
• /
• 2000

A magnet assembly is a critical element of a nuclear magnetic resonance(NMR) based sensor. Magnetic flux density and homogeneity are essential to its optimum performance. Geometry and magnet material properties determine the magnetic flux density and homogeneity of the assembly. This study was carried out to develop the design for a magnet assembly. A 2-D finite element model for the magnetic assembly was developed using ANSYS and evaluated the effects of adding shimming frames and steel bars in the corners of the rectangular steel cover which surrounded the magnet. The assembly was manufactured and evaluated. According to the ANSYS model, modified pole frames increased magnetic flux density by 8.3% and increased homogeneity by 83%. Addition of steel bars in the corners increased the magnetic flux density by 1%, and improved homogeneity up to three times. The difference between simulated and measured magnetic flux densities at the center point of the air gap was within 2.4%.

• 대한방사선치료학회지
• /
• 제29권1호
• /
• pp.19-26
• /
• 2017

목 적: 양성자 치료계획에서 metal 재질의 fiducial marker에 의한 선량 계산오차를 최소화하려면 density override의 적용은 매우 중요하다. 하지만 실제 metal 재질로 density override을 할 경우 정확한 contouring 및 range compensator 제작에 어려움이 있기에 본 연구에서는 fiducial marker의 주변 재질로 density override를 시행하고 fiducial marker의 위치, 재질, beam의 개수에 따른 선량분포를 비교, 분석하여 평가하고자 한다. 대상 및 방법: Water phantom을 이용하여 fiducial marker의 위치를 proton beam의 최대 비정 끝에서부터 1.5, 2.5, 4.0, 6.0 cm로 설정하고 재질로는 gold, steel, titanium으로 설정하여 실제 metal 재질 및 주변 재질로 density override를 적용한 치료계획을 세웠다. 또한 본원에서 양성자치료를 받은 간암 환자 1명을 선정하여 proton beam의 최대 비정 끝에서부터 0, 1.5, 3.5 cm로 설정하고 재질로는 gold, steel, titanium으로 설정하여 치료계획을 세웠다. Fiducial marker의 재질, 위치 및 beam의 개수에 따른 PTV 내에 Homogeneity Index(HI), Conformity Index(CI), 종양에 가장 근접한 Organ At Risk(OAR)인 Esophagus의 maximum dose을 평가 지표로 설정하고 비교 분석하였다. 결 과: Water phantom 및 간암 환자를 대상으로 한 치료계획에서 fiducial marker의 위치에 따른 Homogeneity Index를 분석한 결과 실제 metal 재질로 density override 했을 때보다 주변 재질로 density override했을 때 Homogeneity Index가 감소했으며 주변 재질의 density override에서 하나의 beam에 대해서는 최대 비정 끝에서 멀리 위치할수록, 두 개 이상의 beam에서는 isocenter에 가까이 위치할수록 Homogeneity Index가 증가하였다. Fiducial marker의 위치에 따른 Conformity Index 및 종양 주위 OAR의 maximum dose를 분석한 결과 주변 재질로 density override 했을 때 Conformity Index는 1에 가까웠으며 OAR의 maximum dose는 크게 감소했다. 결 론: 일반적으로 임상에서 사용하는 작은 fiducial marker에 대해서 실제 metal 재질이 아닌 주변 재질로 density override 했을 때 선량 균등도 및 target coverage를 높이는 동시에 주변 정상조직에 대한 선량을 줄일 수 있었다. 따라서 fiducial marker을 최대한 피해서 치료계획을 세우는 것이 바람직하지만 beam path 상에 fiducial marker가 있는 경우 주변 재질의 density override 시행함으로써 보다 정밀한 양성자 치료 효과를 기대할 수 있을 것으로 사료된다.

• Advances in materials Research
• /
• 제9권2호
• /
• pp.155-170
• /
• 2020

In this paper, using the recently introduced analytical approach for the analysis of mass and heat transfer during film growth in reactors for epitaxy from the gas phase, these processes are analyzed taking into account natural convection and the possibility of changing the rate of chemical interaction between reagents. As a result of the analysis, the conditions under which the homogeneity of the grown epitaxial layers increases with a change in the values of the parameters of the growth process are formulated.