• Tribology and Lubricants
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• v.14 no.2
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• pp.21-25
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• 1998

This paper presents the experimental results of the friction characteristics of double liptype oil seals which show an improvement in sealing performance over single lip-type oil seals. The major differences between two oil seals are the number of contact lip, and seal materials; Nitrile Butadine Rubber(NBR) and urethane rubber. The measured results show that the friction torques of double lip seals show 12-17% increases compared with those of single lip-type seals. But the sealing performance and service life of double lip oil seals have been increased and stabilized due to an optimized design of the seal lip and material properties.

• Journal of Information Display
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• v.5 no.4
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• pp.7-11
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• 2004

Effects of base vacuum level on the electrical and optical characteristics of the plasma display panel (PDP) were investigated. The relationship between efficiency and base vacuum level before filling discharge gas was analyzed. For the base vacuum level of $1{\times}10^{-4}$ torr, firing voltage of a 2-inch diagonal PDP panel was 232 V at the discharge gas pressure of 400 torr and luminous efficiency was 1.5 lm/W at 180V sustaining pulse. On the other hand for $1{\times}10^{-6}$torr, the firing voltage was reduced to 215 V and luminous efficiency was improved considerably to 2.5 lm/W. We successfully demonstrated the smooth operation of tip-less PDP fabricated using vacuum in-line sealing method.

• Tribology and Lubricants
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• v.13 no.3
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• pp.56-62
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• 1997

Sealing an oil-air mixture plays important roles to have an enhanced lubrication for high speed spindle. High speed spindles require non-contact type sealing mechanism. In this study, an optimum seal design to minimize leakage is concerned in the aspect of flow control. This paper categorizes geometries of mostly used non-contact type seals and analyzes each leakage characteristics to minimize a leakage on sealing area. Effect of minimum clearance and its position are considered according to variation of detail geometry. The estimation of non-leaking property is determined by amount of pressure drop in the leakage path assuming constant leakage flow. To simulate an oil jet or oil mist type high speed spindle lubrication, the working fluid is regarded as two phases that are mixed flow of oil phase and air phase. Both of the turbulence and the compressible flow model were introduced in CFD(Computational Fluid Dynamics) analysis. Design parameters has been induced to minimize leakage in limited space, and a methodological study on geometrical optimization has been conducted.

• Tribology and Lubricants
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• v.20 no.5
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• pp.231-236
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• 2004

Sulfur Hexafluoride, S $F_{6}$ is widely used for leak detection and as a gaseous dielectric in transformers, condensers and circuit breakers. S $F_{6}$ gas is also effective as a cleanser in the semiconductor industry. This paper presents a numerical study of the sealing force of disk type seal in S $F_{6}$ gas safety valve. The sealing force on the disk seal is analyzed by the FEM method based on the Taguch's experimental design technique. Disk seals in S $F_{6}$ gas safety valve are designed with 9 design models based on 3 different contact length, compressive ratio and gas pressure. The calculated results of Cauchy stress and strain showed that the sealing characteristics of Teflon $^{ }$PTFE is more effective compared to that of FKM(Viton), which is related to the stiffness of the materials. And also, the contact length of the disk seal is important design parameter for sealing the S $F_{6}$ gas leakage in the safety valve.afety valve.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.23 no.6 s.165
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• pp.895-902
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• 1999

This paper deals with a numerical study of the tribological contact stress distributions of elastomeric lip seals for oscillating shafts when the sealing interference and band width between the lip ease or contact seals and the shaft are present. Using the finite element method the contact stress and band width of scraper seals are analyzed for the sealing interference including some nonlinearities such as geometrical nonlinearity, material nonlinearity and nonlinear contact boundary condition. The FEM results showed that the contact stress concentrated on the contacting lip zone between the contacting edge of lip and the shaft for the increased interference. In double lip scraper seals, ole maximum contact stress of the dust lip, which is used to exclude foreign contaminants is six times higher than that of the primary sealing lip, which is used to contain lubricants.

• Resources Recycling
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• v.14 no.4 s.66
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• pp.22-33
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• 2005

Four sheet-shaped and one soft-shaped self-sealing waterproof materials were prepared to recycle some GRT(Ground Rubber Tires). Their physical properties were tested to consider characteristics of them. The self-sealing waterproof materials were consisted of GRT/super absorbent polymer(SAP)/binder and mold by a hot press after mixing with a batch-typed internal mixer. The average size of GRT particles was -40 mesh, SAPs were commercial GE-500F and poly(AM-SAS-AA) prepared in this work. Binders were PU. EVA, LDPE, SBR, and poly(2-EHA). And PU film was attached to improve the properties of waterproof materials. Characteristics of self-sealing waterproof materials consisted of by GRT/GE-500F/EV-600/PU film and GRT/GE-500F/SBR(vulcanization)/PU film among the developed self-sealing waterproof materials were similar to the commercial products. And properties of the soft-shaped self-sealing waterproof materials consisted of by GRT/GE-500F/Po1y(2-EHA) and CRT/Poly(AM-SAS-AA)/poly(2-EHA) were improved within from four times to twenty times compared to the one oi the commercial products.

• Journal of Information Display
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• v.4 no.3
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• pp.6-11
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• 2003

We have fabricated a carbon nanotube field emission display (CNT-FED) panel with a 2-inch diagonal size by using a screen printing method and vacuum in-line sealing technology. The sealing temperature of the panel was around 390$^{\circ}C$ and the vacuum level was obtained with 1.4x$10^{-5}$torr at the sealing. When the field emission properties of a fabricated and sealed CNT-FED panel were characterized and compared with those of the unsealed panel which was located in a test chamber of vacuum level similar with the sealed panel. As a result, the sealed panel showed similar I-V characteristics with unsealed one and uniform light emission with very high brightness at a current density of 243 ${\mu}A/cm^2$, obtained at the electric field of 10 V/${\mu}m$.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.9
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• pp.571-576
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• 2015

In this study, we developed a lead-free $P_2O_5-V_2O_5-ZnO$ glass frit for sealing OLED using laser irradiation. The frit satisfied the characteristics required for laser sealing such as low glass transition temperature, low coefficient of thermal expansion (CTE), high water-resistance, and high absorption at the wavelength of the laser beam. Ceramic fillers were added to the glass frit in order to further reduce and match its CTE with that of the commercial glass substrate. The addition of Zirconium Tungsten Phosphate (ZWP) to the frit yielded the most desirable results, reducing the CTE to $45.4{\times}10^{-7}/^{\circ}C$, which is very close to that of the glass substrate ($44.0{\times}10^{-7}/^{\circ}C$). Successful formation of a solid sealing layer was observed by optical and scanning electron microscopy.

• Asian-Australasian Journal of Animal Sciences
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• v.33 no.7
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• pp.1103-1112
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• 2020

Objective: To measure whether a microbial additive could effectively improve the fermentation quality of delayed-sealing (DS) silage, we studied the effects of inoculants of lactic acid bacteria (LAB) and cellulase enzyme on microbial populations, ensiling characteristics, and spoilage loss of DS silage of Napier grass in Africa. Methods: Quick-sealing (QS) and DS silages were prepared with and without LAB (Lactobacillus plantarum) inoculant, cellulase enzymes, and their combination. The QS material was directly chopped and packed into a bunker silo. The DS material was packed into the silo with a delay of 24 h from harvest. Results: In the QS silage, LAB was dominant in the microbial population and produced large amounts of lactic acid. When the silage was treated with LAB and cellulase, the fermentation quality was improved. In the DS silage, aerobic bacteria and yeasts were the dominant microbes and all the silages were of poor quality. The yeast and mold counts in the DS silage were high, and they increased rapidly during aerobic exposure. As a result, the DS silages spoiled faster than the QS silages upon aerobic exposure. Conclusion: DS results in poor silage fermentation and aerobic deterioration. The microbial additive improved QS silage fermentation but was not effective for DS silage.

• Korean Journal of Materials Research
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• v.1 no.4
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• pp.221-228
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• 1991

In this study we have investigated the sealing characteristics of glasses suitable for producing the magnetic gap of the ferrite head cores which have been widely used for VTR and computer magnetic heads. $PbO-B_2O_3$ g1asses were evaluated by measuring microhardness, thermal expansion coefficient and sliding wear resistance. Concentration distribution of elements at the interface was observed by WDS. wettability was measured by high temperature microscopy. The results were as follows ; 1. In sealing glasses of $PbO-B_2O_3$ system, thermal expansion coefficient and wear volume were increased with increasing PbO content, and were decreased with increasing $B_2O_3$ content. 2. The contact angle of $PbO-B_2O_3$ Systems was mainly influenced by PbO content. 3. The sealing temperature showed a tendency to decrease proportionally with the increase of the coefficient of thermal expansion. 4. The diffusion at the interface between Mn-Zn single crystal ferrite and sealing glasses of $PbO-B_2O_3$ system was dominated by small amount of diffusion of ferrite content into glass part, which was very little affected by sealing heat treatment time.