• Biotechnology and Bioprocess Engineering:BBE
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• v.5 no.1
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• pp.65-70
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• 2000

An approximated analytical solution of mathematical model for the three phase fluidized bed bioreactor (TFBBR) was proposed using the linearization technique to describe oxygen utilization rate in wastewater treatment. The validation of the model was done in comparison with the experimental results. Satisfactory agreement was obtained in the comparison of approximated analytical solution and numerical solution in the oxygen concentration profile of a TFBBR. The approximated solutions for three modes of the liquid phase flow were compared. The proposed model was able to predict the biomass concentration, dissolved oxygen concentration the height of efficient column, and the removal efficiency.

• Steel and Composite Structures
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• v.4 no.2
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• pp.113-132
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• 2004

Double skin composite element (DSCE) is a novel form of construction comprising two skins of profiled steel sheeting with an infill of concrete. DSCEs are thought to be applicable as shear or core walls in a building where they can resist in-plane loads. In this paper, the behaviour of DSCE subjected to combined bending and shear deformation is described. Small-scale model tests on DSCEs manufactured from micro-concrete and very thin sheeting were conducted to investigate the flexural and shear behaviour along with analytical analysis. The model tests provided information on the strength, stiffness, strain conditions and failure modes of DSCEs. Detailed development of analytical models for strength and stiffness and their performance validation by model tests are presented.

• Steel and Composite Structures
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• v.18 no.3
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• pp.775-791
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• 2015

An analytical and experimental investigation is performed into the mechanical behavior of carbon-fiber/epoxy woven coned annular disk springs. An analytical approach is presented for predicting the deformation behavior of disk springs of specially orthotropic laminates with arbitrary geometric parameters. In addition, an analytical methodology is proposed for obtaining the deformation behavior of a stack of disk springs. The methodology is capable of accounting for parallel and series arrangements for uniform and irregular stacks. Element and assembly experimental results are used to validate the proposed method showing how to achieve flexible spring rates at various deflections ranges. This manuscript also provides guidelines for design and validation of disk spring assemblies.

• Analytical Science and Technology
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• v.26 no.2
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• pp.154-163
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• 2013

The maximum residue limits of pyrimisulfan is set as 0.05 mg/kg in rice in 2011, so very reliable and sensitive analytical method for pyrimisulfan residues is required for ensuring the food safety of pyrimisulfan residues in agricultural products. In this study, a rapid and sensitive analytical method was developed and validated using liquid chromatography electrospray ionization tandem mass spectrometry (LC-MS/MS) for the determination of herbicide pyrimisulfan residues in agricultural products. Average recoveries of pyrimisulfan ranged from 88.7 to 99.3% at the spiked level of 0.005 mg/kg and from 90.1 to 94.2% at the spiked level of 0.05 mg/kg, while the relative standard deviation was less than 10%. Linear range of pyrimisulfan was between 0.01~1.0 ${\mu}g/mL$ with the correlation coefficient ($r^2$) 0.999 and limit of quantification was 0.005 mg/kg. The results of method validation were satisfied Codex guideline. The results revealed that the developed and validated analytical method is possible for pyrimisulfan determination in agricultural product samples and will be used as an official analytical method.

• Food Science and Industry
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• v.55 no.1
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• pp.23-32
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• 2022

Processed foods using food additives designated as the other countries but not yet in Korea can be mixed and distributed among imported foods in Korea. Accordingly, it is necessary to develop an analysis method of undesignated food additives in order to continuously monitor. This paper introduced a study on the development and validation of analytical methods conducted in academia. The development of analytical methods was conducted using the analytical methods presented in previous studies. We first exhibited that simultaneous analysis of 12 food dyes was easy to reproduce, but the second introduced analytical method of emulsifiers cannot be utilized analysis using expensive equipment not provided in general laboratories, and it is difficult to reproduce due to the old publications. Therefore related national institutions, research and industry-academia circles need to constantly conduct research on the development of analytical methods for undesignated food additives.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.16 no.2
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• pp.91-100
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• 2006

The purpose of this study was to validate alternative method by using non-carcinogenic, and less toxic solvents than NIOSH analytical method 5524 for measuring the airborne MWFs in workplaces. In laboratory tests, the ETM solvents(mixture of same volume for ethyl ether, toluene, and ethanol) were selected. The alternative method of analyzing MWFs, referred to as the ETM solvent extraction method, showed 0.04 mg/sample as LOD, and 0.15 mg/sample as LOQ. The analytical precision (pooled CV, coefficient of variation) of the ETM solvent extraction method for analyzing the straight, soluble, semisynthetic, and synthetic metalworking fluid was 1.5%, 2.0%, 2.6%, 1.6%, respectively, which was similar to the precision (2.6%) of NIOSH analytical method (NIOSH 0500) for total dust. The analytical accuracy by recovery test, spiked mass calculated as extractable mass, was almost 100%. As the result of storage stability test, metalworking fluid samples should be stored in refrigerated condition, and be analyzed in two weeks after sampling. The 95% confidence limit of the estimated total standard error for the ETM solvent extraction method for analyzing the straight, soluble, semisynthetic, and synthetic metalworking fluid was ${\pm}12.6%$, ${\pm}12.5%$, ${\pm}14.0%$, and ${\pm}13.6%$, respectively, which satisfied the OSHA sampling and analytical criteria.

• Toxicological Research
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• v.31 no.3
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• pp.299-305
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• 2015

An HPLC analytical method was validated for the quantitative determination of biogenic amines in agricultural products. Four agricultural foods, including apple juice, Juk, corn oil and peanut butter, were selected as food matrices based on their water and fat contents (i.e., non-fatty liquid, non-fatty solid, fatty liquid and fatty solid, respectively). The precision, accuracy, recovery, limit of detection (LOD) and quantification (LOQ) were determined to test the validity of an HPLC procedure for the determination of biogenic amines, including tryptamine, ${\beta}$-phenylethylamine, putrescine, cadaverine, histamine, tyramine, spermidine and spermine, in each matrix. The LODs and LOQs for the biogenic amines were within the range of 0.01~0.10 mg/kg and 0.02~0.31 mg/kg, respectively. The relative standard deviation (RSD) of intraday for biogenic amine concentrations ranged from 1.86 to 5.95%, whereas the RSD of interday ranged from 2.08 to 5.96%. Of the matrices spiked with biogenic amines, corn oil with tyramine and Juk with putrescine exhibited the least accuracy of 84.85% and recovery rate of 89.63%, respectively, at the lowest concentration (10 mg/kg). Therefore, the validation results fulfilled AOAC criteria and recommendations. Subsequently, the method was applied to the analysis of biogenic amines in fermented agricultural products for a total dietary survey in Korea. Although the results revealed that Korean traditional soy sauce and Doenjang contained relatively high levels of histamine, the amounts are of no concern if these fermented agricultural products serve as condiments.

• Mass Spectrometry Letters
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• v.10 no.1
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• pp.38-42
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• 2019

Damaurone D belongs to the genus Rosa and is a traditional medicinal product used for the treatment of depression, inflammation, and infectious diseases. The purpose of this study was to develop a simple liquid chromatography-tandem mass spectrometry method for the detection of damaurone D in rat plasma and to demonstrate its application in pharmacokinetic studies. Damaurone D and berberine (internal standard) were extracted with acetonitrile using a protein precipitation method. Mass transition was monitored in multiple reaction monitoring mode at m/z $323.2{\rightarrow}267.0$ for damaurone D and m/z $336.1{\rightarrow}320.0$ for berberine in positive ion mode. Analytical validation was conducted by evaluating the specificity, linearity, accuracy, precision, matrix effect, extraction recovery, and stability. The calibration curves were linear over 2-1000 ng/mL. The intra- and inter-day precision and accuracy of quality control samples were 4.79-13.33% and 86.23-102.75%, respectively. The matrix effect and extraction recovery were 96.11-98.47% and 96.11-102.25%, respectively. In the pharmacokinetic study after intravenous administration of damaurone D at a dose of 3 mg/kg in rats, the area under the curve and clearance of damaurone D in rat plasma were $16750.26{\pm}2676.10min{\cdot}ng/mL$ and $182.44{\pm}31.36mL/min/kg$, respectively.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.9
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• pp.1091-1096
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• 2017

The aim of this study was the validation of a modified analytical method for determination of oxypaeoniflorin and paeoniflorin in Moutan Cortex Radicis extract. For validation of the analytical method, we modified established analytical methods and validated improvement. For validation, the specificity, linearity, precision, accuracy, limit of detection (LOD), and limit of quantification of oxypaeoniflorin and paeoniflorin were measured by high performance liquid chromatography. The results show that the correlation coefficients of the calibration curve for oxypaeoniflorin and paeoniflorin were 1.0000 and 0.9998, respectively. The LOD for oxypaeoniflorin and paeoniflorin were $0.23{\mu}g/mL$ and $0.25{\mu}g/mL$, respectively. The inter-day and intra-day precision values of oxypaeoniflorin and paeoniflorin were 0.70~3.19% and 1.74~2.43%, and 0.32~0.92% and 0.62~2.28%, respectively. The inter-day and intra-day accuracies of oxypaeoniflorin and paeoniflorin were 98.33~102.11% and 97.72~118.12%, and 98.44~101.56% and 97.10~112.00%, respectively. Therefore, the analytical method was validated for the detection of oxypaeoniflorin and paeoniflorin in Moutan Cortex Radicis.

• Smart Structures and Systems
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• v.26 no.3
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• pp.391-401
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• 2020

The present article reports the feasibility of the electrical energy generation from ambient low-frequency vibration using a piezoelectric material mounted on a bimorph cantilever beam actuator. A corresponding higher-order analytical model is developed using MATLAB in conjunction with finite element method under low-frequency with both damped and undamped conditions. An alternate model is also developed to check the material and dimensional viability of both piezoelectric materials (mainly focussed to PVDF and PZT) and the base material. Also, Genetic Algorithm is implemented to find the optimum dimensions which can produce the higher values of voltage at low-frequency frequencies (≤ 100 Hz). The delamination constraints are employed to avoid inter-laminar stresses and to increase the fracture toughness. The delamination has been done using a Teflon sheet sandwiched in between base plates and the piezo material is stuck to the base plate using adhesives. The analytical model is tested for both homogenous and isotropic material characteristics of the base material and extended to investigate the effect of the different geometrical parameters (base plate dimensions, piezo layer dimensions and placement, delamination thickness and placement, excitation frequency) on the model responses of the bimorph cantilever beam. It has been observed that when the base material characteristics are homogenous, the efficiency of the model remains higher when compared to the condition when it is of isotropic material. The necessary convergence behaviour of the current numerical model has been established and checked for the accuracy by comparing with available published results. Finally, using the results obtained from the model, a prototype is fabricated for the experimental validation via a suitable circuit considering Glass fibre and Aluminium as the bimorph material.