• KSTLE International Journal
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• v.1 no.1
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• pp.59-62
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• 2000

This paper deals with an experimental study on the dynamic response of an elastomeric oil seal when the interferences between shaft and lip as well as the dynamic eccentricities are present. The dynamic response of seal lip in oil seals was observed with the aid of an image processing apparatus. The temperature of the seal lip edge, friction torque and the dynamic sealing gap between shaft and lip are measured at different conditions of the initial interference and the shaft eccentricity, The data were simultaneously measured under dynamic conditions. Experimental results show that, as the shaft speed is increased, S/e$_{d}$ has nearly reached a constant asymptotic value fur a certain range of shaft speeds. The results indicate that the gap separation between shaft and lip is provided due to the shaft eccentricity because the seal lip cannot follow quickly the radial displacements with increasing shaft speed.d.

• Korea Logistics Conference
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• v.13 no.2
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• pp.85-97
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• 2005

• Korea Information Processing Society Review
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• v.12 no.5
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• pp.66-74
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• 2005

• 한국환경농학회:학술대회논문집
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• 2011.07a
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• pp.207-222
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• 2011

Relationships between soil saturated hydraulic conductivity ($K_s$) and porosity (${\phi}$) have been developed over many years; however, use of these relationships for evaluating rain-induced seals is limited mainly because of difficulties in estimating seal pore-size characteristics. The objectives of this study were to evaluate the $K_s$ of soil surface seals over a range of thicknesses, where seal thickness was determined using a High-Resolution-Computed-Tomography (HRCT) scanner, and to investigate relationships between $K_s$ and ${\phi}$ of developing seals in samples with equivalent diameters (e.d.) ${\geq}15\;{\mu}m$. A Mexico silt loam soil was packed to a bulk density (${\rho}_b$) of $1.1\;Mg\;m^{-3}$ in cylinders 160-mm i.d. by 160-mm long and subjected to $61-mm\;h^{-1}$ simulated rainfall having a kinetic energy (KE) of $25\;J\;m^{-2}\;min^{-1}$ for 7.5, 15, 30, and 60 min to create a range in seal development. Thicknesses of the seal layers were determined by analysis of HRCT images of seals. The $K_s$ values of the seals were estimated using an effective $K_s$ value ($K_{s-eff}$). The $K_s-{\phi}$ relationship was described by a Kozeny and Carmen equation, $K_s=B{\phi}^n$; where B and n are empirical constants and n = 31. This approach explained 86% of the variation between $K_s$ and ${\phi}$ within the soil seals. Knowledge of surface seal information and hydraulic conductivity can provide useful information to use in management of sites prone to sealing formation.

• Design & Manufacturing
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• v.14 no.4
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• pp.1-10
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• 2020

The seal plays a role in preventing oil leakage when the lip and the rotating shaft come into contact with the fluid and air pressure. Recently, micro dimples or micro pockets are processed and used on the lubrication surfaces of thrust bearings, mechanical bearings, and piston rings. Compared to a smooth surface, micro dimples reduce friction and increase the life of parts. This paper analyzed various kinds of micro dimple shapes on the sealing surface, i.e. circle, rectangle, triangle, and trapezoid. For this purpose, Introduced the design of experiments to work out a micro dimple configuration, unlikely to be damaged from cracks and low in contact stress. As a result, the triangular dimple showed the best results. Optimal factors were dimple size 0.15 mm, dimple depth 0.0383 mm, dimple density 40%, and the maximum equivalent stress was 9.1455 MPa, and the maximum contact pressure was 9.6612 MPa. This paper analyzed the optimal shape of dimples by finite element analysis. As a research project, experiments and comparative analysis of micro dimple shapes are needed.

• Journal of Environmental Health Sciences
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• v.31 no.6
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• pp.457-466
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• 2005

Industrial plasticizers such as phthalates can induce peroxisome proliferation. A growing concern among environmental and health groups has arisen because phthalates such as di-2-ethy1hexy1 phthalate (DEHP) and DBP may cause hormonal disorders, reproductive toxicity, hepatocellular tumors, genital disorders owing to a capacity to bind estrogen receptors, and a low-dose toxic action during certain periods of fetal development. Phthalate esters are used extensively as a plasticizer for plastic manufacture such as PVC bags and medical devices. This study investigated the effects of leached components from spring water container's cap and seal film. Phthalates, e.g. dimethy1 phthalate (DMP), diethy1 phthalate (DEP), di-n-buty1 phthalate (DBP), benzy1buty1 phthalate (BBP), di-(2-ethy1hexy1) phthalate (DEHP), and bisphenol A (BPA) were measured in the spring water. The bisphenol A was not detected or below the detection limit on the leaching from cap, sealing or spring water. DEHP were detected 90-116 ppb on the leaching from seal after 2 weeks, and 0.48-0.51 ppb from the spring water after I week. BBP were measured from seal within 1 week 25.4-66 ppb and below 0.12 ppb from spring water within 2 days. DMP were detected from seal within 2 weeks 51-68.5 ppb and 0.12 ppb after 2 weeks. DEP were measured from seal within 2 weeks 48.1-141 ppb and the concentrations were increased by the time from 0.10 to 0.31 ppb at spring water. DBP were detected from the seal within 2 weeks 92.3-5100 ppb and the concentration were decreased by the time from 0.24 to 0.10 ppb at spring water. These results indicate that some phthalate esters contaminated with spring water using the intact cap and seal film. It is concluded that the measured levels of phthalates leaching from these materials might in vivo only be slightly less than 1/10 of the LOAEL.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.34 no.4
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• pp.11-16
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• 2011

Information of freight tracking and tracing is one of core elements in logistics point of view. We can monitor the vehicle or vessel where freights are loaded and get the in-transit data via GPS. However, security problem exists after the shipments are unloaded. RFID is well utilized for securing the container which products are stuffed into. International standard organization sets relevant specification and e-seal appears to be at issue. The paper investigates current status of corresponding technology and proposes the policy for development of logistics industry.

• Restorative Dentistry and Endodontics
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• v.44 no.2
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• pp.18.1-18.9
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• 2019

Objective: This study evaluated the presence of residual root canal filling material after retreatment using micro-computed tomography (micro-CT). Materials and Methods: Extracted human teeth (single- and double-rooted, n = 21/each; C-shaped, n = 15) were prepared with ProFile and randomly assigned to three subgroups for obturation with gutta-percha and three different sealers (EndoSeal MTA, EndoSequence BC sealer, and AH Plus). After 10 days, the filling material was removed and the root canals were instrumented one size up from the previous master apical file size. The teeth were scanned using micro-CT before and after retreatment. The percentage of remaining filling material after retreatment was calculated at the coronal, middle, and apical thirds. Data were analyzed using the Kruskal-Wallis test and Mann-Whitney U test with Bonferroni post hoc correction. Results: The tested sealers showed no significant differences in the percentage of remaining filling material in single- and double-rooted teeth, although EndoSeal MTA showed the highest value in C-shaped roots (p < 0.05). The percentage of remaining filling material of AH Plus and EndoSeal MTA was significantly higher in C-shaped roots than in single- or double-roots (p < 0.05), while that of BC sealer was similar across all root types. EndoSeal MTA showed the highest values at the apical thirds of single- and double-roots (p < 0.05); otherwise, no significant differences were observed among the coronal, middle, and apical thirds. Conclusions: Within the limitations of this study, a large amount of EndoSeal MTA remained after retreatment, especially in C-shaped root canals.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.6
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• pp.916-922
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• 2017

Security systems for inland cargo truck transportation are mostly limited to route tracking for safe and efficient transportation. With this route tracking system, the status of cargo trucks can be monitored easily within inland boundaries. In case of oil transportation by land, however, security systems ensuring transportation of a designated quantity of products have been subject to extensive research since thefts and substitution by a similar product in the transportation process have emerged as a social problem. Security devices installed in an oil tank truck must meet the explosion-proof performance standards and be applicable to varying types of trucks. Accordingly, a wireless electronic seal with RF communication functions is considered to be the most appropriate method, but e-seals on moving vehicles require such levels of performance and reliability that can overcome certain challenges including changing radio waves and topographical impediments. Considering these characteristics of oil tank trucks, this study proposes an stabilization method to enhance the RF communication performance of e-seals, based on radio simulation and experiment findings.

• Bulletin of the Korean Chemical Society
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• v.34 no.5
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• pp.1345-1348
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• 2013

We investigated the tribochemical and wear properties of Polytetrafluoroethylene (PTFE) based polymer matrix composites with nanoceramic (NC) ${\beta}$-sialon, and $Al_2O_3$ particles for the mechanical seal applications at low temperature. SEM showed that NC particles were homogeneously distributed in the polymer matrix and initiated the formation of the supramolecular spherulites around NC. From the temperature stimulated depolarization (TSD) current results, it was analyzed that the surface charge on nanoceramic affected the formation of the spherulites structure. 2 wt % $Al_2O_3$ NC did not degrade the mechanical properties of PTFE so that composites showed the similar values of tensile strength, elongation at the rupture and friction coefficient as those of neat PTFE. However, the composite with 2 wt % $Al_2O_3$ NC revealed the improved wear resistance, wear rate of 0.4-1.2 mg/h at room temperature and 0.28 mg/h at $-40^{\circ}C$, respectively, while the neat PTFE the 70-75 mg/h at room temperature and 70.3 mg/h at $-40^{\circ}C$.