• Tribology and Lubricants
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• 제28권5호
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• pp.246-251
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• 2012

Disc brakes and brake linings are part of the braking system in automobiles; this system works due to the braking power between the disc and pad. Vehicle braking systems have complex environments due to the geometry of the disk and pad, the material properties, the braking conditions, etc. Braking energy is converted into thermal energy during the braking process, due to the frictional heat between the disc brake and pad. This heat is changed to a heat flux, which affects the thermal stress of the disc. The purpose of this study was to use the fluid dynamics software ANSYS CFX to investigate the inner flow characteristics of the air and the heat transfer of the disc, and to analyze the effects on the thermal stress of the disc brake.

• Computers and Concrete
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• 제23권5호
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• pp.303-309
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• 2019

This study investigates axisymmetric fractional vibration of an isotropic hyperelastic semi-linear thin disc with a view to examine effects of finite deformation associated with the material of the disc and effects of fractional vibration associated with the motion of the disc. The generalized three-dimensional equation of motion is reduced to an equivalent time fraction one-dimensional vibration equation. Using the method of variable separable, the resulting equation is further decomposed into second-order ordinary differential equation in spatial variable and fractional differential equation in temporal variable. The obtained solution of the fractional vibration problem under consideration is described by product of one-parameter Mittag-Leffler and Bessel functions in temporal and spatial variables respectively. The obtained solution reduces to the solution of the free vibration problem in literature. Finally, and amongst other things, the Cauchy's stress distribution in thin disc under finite deformation exhibits nonlinearity with respect to the displacement fields whereas in infinitesimal deformation hypothesis, these stresses exhibit linear relation with the displacement field.

• 한국동물위생학회지
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• 제18권2호
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• pp.163-176
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• 1995

Triphenyl Tetrazolium Chloride(TCC) reduction test is simple and sensitive to some residual antibiotics (especially to penicillin) in milk, but comparatively insensible to sulfo-namides. The volumn of sample is also large. Thus this study was undertaken to increase the detectable level of sulfonamides in raw milk. In this study, we used small transparent plastic hole and pulp disc instead of 10m1 test tube and made test medium in which was added 0.08%TTC, 0.3% agar, 10% skim milk, approximately $10^6$ CFU/ml streptococcus thermophilus and 5ppm Trimethoprim to enhance the sensitivity for sulfonamides The results of TCC reduction test by disc plate method were summarized as follows : 1. sensitivity to residual sulfonamides were much higher than official TCC reduction test. Detectable limites of sulfamethazine, sulfamerazine, sulfathiazole, sulfachloropy-ridazine, sulfadimethoxine, sulfamononethoxine, sulfadiazine and sulfaquinoxaline were 0.1-0.5ppm levels. 2. Detectable limites to some antibiotics were simillar or good than that of official method as 0.005-0.1ppm to three ${\beta}$ -lactams, 0.25-0.5ppm to one macrolide, 2-10ppm to three aminoglycosides, 0.2-0.5ppm to three tetracycline, 0.1-0.5ppm to chloramphenicol. 3. Only 0.1ml of milk was needed to test and the test medium could be stored appnoximatly 7days in the refrigerator. So test procedure was convenient than offcial method. 4. These results suggest that disc plate method is more useful to detect bacterial growth inhibition substances including sulfonamides in raw milk.

• 대한두경부종양학회지
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• 제19권1호
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• pp.25-33
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• 2003

Background and Objectives: The Herpes Simplex type 2 Defective Infectious Single Cycle virus (DISC virus) is attenuated virus originally produced as viral vaccines but are also efficient gene transfer vehicle. The main goals of this study were to examine the efficiencies of the gene transfer using DISC vectors for various head and neck squamous cell carcinoma cell lines and to evaluate the efficacy of vaccination with DISC virus carrying a immunomodulatory genes (GM-CSF) as cancer therapy in a organotopic oral cavity squamous cell cancer model. Materials and Methods : We determinated the gene transfer efficiency of DISC virus by x-gal stain method and proved gene and protein expression of DISC-GMCSF transfected SCCVII cells by RT-PCR and ELISA method. Also we evaluated the ex vivo vaccination effects of SCCVII/GMCSF (DISC-GMCSF transfected SCCVII vaccine) vaccine on preventing the recurrence of micro-residual tumor. After the vaccination of SCCVII/GMCSF, specific cytotoxic T-cell responses was evaluated by CTL assay. Results: At an MOI of 10 DISC virus showed 64-88% of transfection rates in various head and neck squamous cancer cell lines. SCCVII cells transduced by DISC virus vector (MOI=10) carrying the GM-CSF gene, produced 4.5 nanogram quantities of GM-CSF per $10^6$ cells. In vivo vaccination using tumor cells transduced ex vivo with DISC-GMCSF resulted in better protection rate against subsequent tumor recurrence in organotopic oral cavity cancer model. Although tumor free survival rate was not statistically significantly increased in vaccination group (p=0.078), tumor specific cytotocic T-cell responses were significantly increased in SCCVII/GMCSF vaccination group. Conclusion: These data demonstrate that; 1) The DISC virus vector is capable of efficient gene transfer to various head and neck squamous cancer cell lines, 2) GM-CSF secreting genetically modified tumor vaccine (SCCVII/GMCSF) efficiently protected against tumor recurrence in organotopic micro-residual oral cavity cancer model and produced tumor specific cytotoxic T-cell response. DISC virus-mediated, cytokine gene transfer may prove to be useful as a clinical therapy for head and neck cancers.

• Geomechanics and Engineering
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• 제34권1호
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• pp.103-113
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• 2023

This study focused on understanding the relationship between the design of a tunnel boring machine disc cutter ring and its rock-breaking efficiency, as well as the applicable conditions of different cutter ring types. The discrete element method was used to establish a numerical model of the rock-breaking process using disc cutters with different ring types to reveal the development of rock damage cracks and variation in cutter penetration load. The calculation results indicate that a sharp-edged (V-shaped) disc cutter penetrates a rock mass to a given depth with the lowest load, resulting in more intermediate cracks and few lateral cracks, which leads to difficulty in crack combination. Furthermore, the poor wear resistance of a conventional V-shaped cutter can lead to an exponential increase in the penetration load after cutter ring wear. In contrast, constant-cross-section (CCS) disc cutters have the highest quantity of crack extensions after penetrating rock, but also require the highest penetration loads. An arch-edged (U-shaped) disc cutter is more moderate than the aforementioned types with sufficient intermediate and lateral crack propagation after cutting into rock under a suitable penetration load. Additionally, we found that the cutter ring wedge angle and edge width heavily influence cutter rock-breaking efficiency and that a disc cutter with a 16 to 22 mm edge width and 20° to 30° wedge angle exhibits high performance. Compared to V-shaped and U-shaped cutters, the CCS cutter is more suitable for soft or medium-strength rocks, where the penetration load is relatively small. Additionally, two typical case studies were selected to verify that replacing a CCS cutter with a U-shaped or optimized V-shaped disc cutter can increase cutting efficiency when encountering hard rocks.

• 동의생리병리학회지
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• 제21권1호
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• pp.231-234
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• 2007

Dichlororinated bibenzyl compound (4) has been isolated from the New Zealand liverwort. This compound was elucidated using 1D/2D-NMR and mass spectral method. The compound (3) inhibited the growth of the Gram positive bacterium Bacillus subtilis ATCC 19659, (2 mm inhibition zone and 2 mm inhibition zone at 30 ${\mu}$g/disc), Candida albicans ATCC 14053, (2 mm inhibition zone and 2 mm inhibition zone at 30 ${\mu}$g/disc), and the dermatophytic fungi Trichophyton mentagrophytes ATCC 28185, (12 mm inhibition zone at 30 ${\mu}$g/disc) and Cladosporium resinae ATCC 52833 (2 mm inhibition zone at 30 ${\mu}$g/disc). This bibenzyl compound (4) exhibited antimicrobial activity.

• 한국철도학회논문집
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• 제9권6호
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• pp.677-681
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• 2006

In general, the braking system of high speed train has an important role for the safety of the train. To stop the train safely at its pre-decided position, it is necessary to combine the various brakes properly. The Korean high speed train (HSR-350x) has adopted a combined electrical and mechanical (friction) braking system. In this study, the measuring method that can obtain the disc braking forces and friction coefficient between disc and pad during on-line test of HSR-350x has been suggested and verified through the comparison of the results obtained from this method and those of the results of the dynamo-tests.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 춘계학술대회논문집
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• pp.177-182
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• 2004

Electronic products are subjected to many different types of shock environment. As the Optical Disc Drive (ODD) market grows, the number of failures related to shock increases. Therefore, it is necessary to improve the performance of cushion package as well as the product design. Cushion materials such as expanded polystyrene are often used to protect electronic products from shock environment. In this paper, the drop analysis of the cushion package f3r optical disc drives was carried out with the explicit method of LS-DYNA and verified by the drop test. For the optimization of package, response surface approximation model was created using central composite design. As a result, cushioning performance was improved under the critical condition and practical design guidelines of cushion package were suggested.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 추계학술대회논문집A
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• pp.665-670
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• 2000

The paper presents the dynamic instability of a disc brake pad subjected to distributed friction forces. A brake pad can be modeled as a beam with two translational springs. The study of this prototypical model is intended to provide a fundamental understanding of disc brake pad instabilities. Governing equations of motion are derived form energy expressions and their corresponding solutions are obtained by employing the finite element method. The critical distributed friction force and the instability regions are demonstrated by changing two translational spring constants. Finally, the changes of eigen-frequencies of a beam determining instability types are investigated for various combinations of two spring constants.

• 정보저장시스템학회논문집
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• 제1권1호
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• pp.53-57
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• 2005

In order to measure signal quality of optical disc such as CD or DVD, jitter is used traditionally. The signal attained from a disc by optical pick-up is processed by analog circuits. And then, binary signal can be obtained by using proper silcer. After the signal is changed into binary format, jitter is calculated as a time difference between the binary signal and the reference time. Jitter is used to express the signal quality. In this paper, a new method that is able to offer more precise measurement of the signal quality fur high density optical disc than the jitter is proposed. We named it LPSNR (Level Peak Signal to Noise Ratio). The relationship between bER (bit error rate) and LPSNR is shown in the paper.