• Mass Spectrometry Letters
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• v.14 no.4
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• pp.166-172
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• 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.

• International Journal of Naval Architecture and Ocean Engineering
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• v.12 no.1
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• pp.943-956
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• 2020

In this study, the motion control problem of the vessel towed by a towing ship (tugboat) is considered. The non-powered towed ship is dragged by the towing ship. Even though the towed ship is equipped with propulsion systems, they cannot be used at low or constant speeds due to safety issues. In narrow canals, rivers, and busy harbor areas especially, where extreme tension is required during towing operation, the course stability of the towed vessel depends on the towing ship. Therefore, the authors propose a new control strategy in which the rudder system of the towed vessel is activated to provide its maneuverability. Based on the leader-follower system configuration, a nonlinear mathematical model is derived and a back-stepping control is designed. By simulation and experiment results with a comparison study, the usefulness and effectiveness of the proposed strategy are validated.

• Journal of Fisheries and Marine Sciences Education
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• v.29 no.3
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• pp.857-868
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• 2017

The basic safety training for fisheries is being conducted to cope with an emergency situation and prevent the maritime accidents. A new joined person must be educated the safety training and a refresher must be completed the refresher training course every 5 year in according to the STCW-F and seafarers' Act. In order to achieve the objectives of marine safety training, it is necessary to distinguish the trainees by ship's type and the courses should be implemented in consideration of safety equipment of fishing vessels. However, since the classification criteria of seafarers' Act are unclear, the officer of fishing vessels which is over G/T 25 tons has been trained through the same course and curriculum for merchant ship's seafarers. About 80 % of domestically registered fishing vessels are small size ships(less than 100 tons) and there is not many safety equipment required by law. In case of marine accidents such as collision, the small vessel losses its buoyancy and stability caused by damage of hull. despite fisheries fall into the sea during fishing work in bad weather on the deck, there was no safety equipment by law. So fisheries must be trained by a safety training course suitable for fishing vessel. The purpose of this study is to develope the suitable course for fisheries by analysis current curriculum and rules. so suggested the basic safety training course for fisheries and institutional improvement.

• Journal of the Society of Naval Architects of Korea
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• v.34 no.4
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• pp.1-11
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• 1997

When a barge is towed by a tug boat using a tow line, the barge is frequently subject to a large sway motion induced from its inherent yaw motions. This large sway motion combined with external forces due to winds and waves may makes the towing to be difficult or even dangerous. It has been reported that in worse situations, barges or tugs are capsized. In addition, the large sway motion of the towed barge gives a menace to the safety of ships navigating nearby. This paper is the results of the experimental investigation into the course stability of an 8,000 DWT barge using a Towing Tank and a Circulating Water Channel. Various skegs are designed and course stability tests for the barge with skegs are conducted in calm water and in irregular waves. It is observed that an effective skeg attached to the barge enables the sway motion to be zero while the sway amplitude of the bare hull is around 10 times its breadth.

• Biotechnology and Bioprocess Engineering:BBE
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• v.7 no.4
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• pp.225-230
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• 2002

Experiments on deactivation kinetics of immobilized lipase enzyme from Candida cyl-indracea were performed in stirred bath reactor using rice bran oil as the substrate and temperature as the deactivation parameter. The data were fitted In first order deactivation model. The effect of temperature on deactivation rate was represented by Arrhenius equation. Theoretical equations were developed based on pseudo-steady state approximation and Michaelis -Menten rate expression to predict the time course of conversion due to enzyme deactivation and apparent half-life of the immobilized enzyme activity in PFR and CSTH under constant feed rate polity for no diffusion limitation and diffusion limitation of first order. Stability of enzyme in these continuous reactors was predicted and factors affecting the stability were analyzed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1997.04a
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• pp.55-59
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• 1997

Investigation is performed on the stability of general form of dynamic system whose damping and stiffness are varying in irregular manner along time, which is a preliminary result in the course of research on the characteristic and the control of the stochastic system. The governing equation of the 'parametric' system is derived via F-P-K approach in stochastic sense. The influence on the stability due to the magnitude of auto power spectral density and cross power spectral density of random variation of system parameters is studied and the region is surveyed.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2003.10a
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• pp.73-77
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• 2003

Stability rating of KSR-III rocket engine is conducted based on stability rating tests in the course of development of KSR-III rocket engine. Rocket engine is approved to have combustion stabilization ability when it can suppress the external perturbation or pressure oscillation with finite amplitude and recover the original stable combustion. Rocket engine in flight nay be perturbed with unexpectedly large amplitude and thus a designer should not only assure combustion stabilization ability of the engine but also quantify the stabilization capacity. For this, several quantitative parameters and their evaluation are introduced. To verify dynamic stability of KSR-III rocket engine, five stability rating tests have been conducted. Based on these test results, such parameters are quantified and thereby, the stabilization capacity of KSR-III rocket engine is evaluated.

• Journal of Engineering Education Research
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• v.16 no.1
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• pp.27-34
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• 2013

The purpose of this study is to analyze work values of undergraduates according to major and gender. The result of this research is following. First, undergraduates from engineering and social science department took a very serious view of achievement and leasure of body and mind in work values. Second, undergraduates made much of achievement, job stability, leasure of body and mind, economic compensation and reputation. And undergraduates thought that internal value orientation was more important than external value orientation. Third, two groups had significant difference in service, knowledge pursuit, patriotism, economic compensation, reputation, and indoor activity. Fourth, the result of this analysis according to gender is following. Male undergraduates made much of leasure of body and mind, achievement, job stability, knowledge pursuit, and economic compensation in order. But female undergrduates made much of economic compesation, leasure of body and mind, achievement, and job stability in order. Fifth, that undergraduates make little of domain of service and patriotism gives a suggestion as to improvement of course education. As a result, this study is suggestive of instruction and advice in course search curriculum.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.7
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• pp.800-806
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• 2016

The maneuverability of a tugboat is affected by the slewing motion of a barge while the tug is navigating with the barge in water. Therefore, it is necessary to reduce the slewing motion of the barge to allow for safe towing work. In this study, a water tank experiment was performed to examine the factors affecting the slewing motion of a barge and improve course stability. The characteristics of slewing motion vary according to bow shape. Three barge models, each with a different bow shape, were selected as experimental subjects. A comprehensive analysis was performed to study the effects of various factors on the slewing motion of a barge such as the presence of a skeg and bridle, towing speed, and the length of the towline. The effect of the location of the skeg varied according to bow-hull form. The slewing motion of the barge decreased as the length of the towline increased, and this decrease was even greater when a bridle was connected to the towline. In addition, the slewing motion decreased significantly as the length of the bridle increased. The slewing angles did not show significant change with respect to towing speed.

• Journal of the Korea Fashion and Costume Design Association
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• v.24 no.2
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• pp.1-10
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• 2022

The purpose of this study is to analyze the structural properties of 100% wool fabrics knitted with various stitch types and to evaluate dimensional stability from shrinkage in wet cleaning and drying. Materials were weft-knitted from twenty-four different stitches with 7 gauge using a computerized flatbed knitting machine. Weight, thickness, density, and length were measured. A domestic washing machine and a tumble dryer were used for the shrinkage test. The results are as follows: Knitted fabrics were divided into 3 groups based on weight per unit area. Porous knits show light weight whilst milano, pintuck, rib stitches belong to the heaviest group. A positive correlation between weight and thickness was found and the same result was obtained for wale density and weight. Dimensional shrinkage of knitted fabrics was increased during repetitive wet cleaning and drying regardless of knit stitches. Especially, fabrics knitted with float, tuck, cable, and links & links stitches samples were contracted more than 15% in the first treatment whereas 2x1 rib stitch showed 1% shrinkage rate. Fisherman and milano stitches contracted in both course and wale direction with similar shrinkage rates. However, porous knits with float and tuck stitches shrank in course direction by 20% as well as cable samples contracted from 5% to 20% after repeated washing and drying. On the other hand, 30% and 15% contraction of wale direction occurred in orderly float and links & links stitches, respectively. Machine dried knits have a higher shrinkage rate than air-dried knits, but the drying method did not affect to the direction of contraction. In conclusion, variations of knit, tuck, and float stitches affect knit construction and dimensional stability from shrinkage in wet cleaning and drying of wool knitted fabrics.