• Journal of Korean Neurosurgical Society
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• v.52 no.5
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• pp.472-475
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• 2012

Objective : The aim of this study is to establish the value of hand elevation test as a reproducible provocative test for the diagnosis of carpal tunnel syndrome (CTS). Methods : We had a prospective study of 45 hands of 38 patients diagnosed with CTS between April 2005 and February 2009. The diagnosis of CTS was based on the American Academy of Neurology clinical diagnostic criteria. Experimental and control group patients underwent Tinel's test, Phalen's test, carpal compression test and hand elevation test as provocative tests for CTS. Results : We used chi-square analysis to compare Tinel's test and Phalen's test, carpal compression test with hand elevation test. The sensitivity and specificity of the hand elevation test is 86.7% and 88.9% each. Tinel's test had 82.2% sensitivity and 88.9% specificity. Phalen's test had 84.4% sensitivity and 86.7% specificity. Carpal compression test had 84.4% sensitivity 82.2% specificity. Comparisons of sensitivity and specificity between hand elevation test and Tinel's test, Phalen's test, and carpal compression test had no statistically significant differences. To compare the diagnostic accuracies of four tests, the area under the non-parametric receiver operating character curve was applied. Conclusion : The hand elevation test has higher sensitivity and specificity than Tinel's test, Phalen's test, and carpal compression test. Chi-square statistical analysis confirms the hand elevation test is not ineffective campared with Tinel's test, Phalen's test, and carpal compression test.

• Geomechanics and Engineering
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• v.24 no.4
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• pp.349-358
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• 2021

The Brazilian test has been widely used to determine the indirect tensile strength of rock, concrete and other brittle materials. The basic assumption for the calculation formula of Brazilian tensile strength is that the elastic moduli of rock are the same both in tension and compression. However, the fact is that the elastic moduli in tension and compression of most rocks are different. Thus, the formula of Brazilian tensile strength under the assumption of isotropy is unreasonable. In the present study, we conducted Brazilian tests on flat disk-shaped rock specimens and attached strain gauges at the center of the disc to measure the strains of rock. A tension-compression bi-modular model is proposed to interpret the data of the Brazilian test. The relations between the principal strains, principal stresses and the ratio of the compressive modulus to tensile modulus at the disc center are established. Thus, the tensile and compressive moduli as well as the correct tensile strength can be estimated simultaneously by the new formulas. It is found that the tensile and compressive moduli obtained using these formulas were in well agreement with the values obtained from the direct tension and compression tests. The formulas deduced from the Brazilian test based on the assumption of isotropy overestimated the tensile strength and tensile modulus and underestimated the compressive modulus. This work provides a new methodology to estimate tensile strength and moduli of rock simultaneously considering tension-compression bi-modularity.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1994.03a
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• pp.139-148
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• 1994

An experimental study on material characterization and mechanical properties of SMC(Sheet Molding Compounds) compression molding parts was carried out. Simple compression test using grease oil as a lubricant was carried out to characterize flow stress of SMC at elevated temperatures. Two different mold temperatures, 130$^{\circ}C$ and 150$^{\circ}C$ and two different mold speeds, 15, 45mm/min were used for preparing the specimen of SMC compression molding parts. Surface roughness, tensile, and 3-point bending tests were used to determine the effects of molding temperatures and speeds on mechanical properties of compression molded SMC parts.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2001.05a
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• pp.13-15
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• 2001

Compression test has been used to measure material flow stress due to limited capability of tensile test at the fast strain rate. Since the frictional stress unavoidable during compression test should be properly eliminated from the measured stress, calibration of the measured stress by using friction factor has been made for the flow stress measurement. Also, calibrated stresses by interrupted and continuous compression tests have been compared with the true stress measured by tensile test at $0.2\%$ carbon steel.

• Journal of the Korean Wood Science and Technology
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• v.48 no.4
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• pp.450-457
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• 2020

Single pellet press technology allows for fast, low-cost, and small-scale tests to investigate pelletizing characteristics. We estimated proper compression ratios for five Korean domestic wood species through predicted relationships between pelletizing pressure P_x and compression ratio based on experimental data obtained from a single pellet press unit. The pressures required to obtain a 6-mm-diam pellet of density 1200 kg/㎥ were estimated as 111 MPa for Populus davidiana, 133 MPa for Robinia pseudoacacia, 136 MPa for Quercus mongolica, 97 MPa for Pinus densiflora, and 127 MPa for Pinus rigida. On the basis of these pressures, we estimated proper compression ratios to be within the range 7.676-8.410 for these species, and we found the compression ratios needed for hardwood species to be somewhat higher than those needed for softwood species to obtain the pellet density of 1200 kg/㎥.

• Geomechanics and Engineering
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• v.2 no.4
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• pp.303-319
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• 2010

The effect of grain crushing on the deformation of sand in 1D compression and 1D creep at high stresses was investigated theoretically and experimentally. An approach was proposed to formulate the process of grain crushing in sand in accordance with the laws of fracture mechanics and energy conservation. With this approach, the relation between the void ratio and the amount of grains crushed in 1D compression was derived. Laboratory test data were used to verify this derived relation. In addition, it was observed that there are similarities in evolution of grain size distribution in 1D compression and 1D creep tests. This implies that the changes in microstructure in sand under 1D compression and 1D creep are comparable.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2002.05a
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• pp.17-20
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• 2002

Recently tube hydroforming technology has been one of the most important technology in automotive industry in the point of saving weight and high quality for collision accidents. In this paper, experimental studies for axial compression tests of hydroformed tubes are performed to investigate the collapse absorption characteristics. The collapse absorption abilities are discussed and compared for as-received, hydroformed, and press formed tubes.

• Proceedings of the Korean Nuclear Society Conference
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• 1997.10a
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• pp.225-230
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• 1997

Discrete Wavelet Transforms (DWTs) are recent mathematics, and begin to be used in various fields. The wavelet transform can be used to compress the signal and image due to its inherent properties. We applied the wavelet transform compression and reconstruction to the neutron cross section data. Numerical tests illustrate that tile signal compression using wavelet is very effective to reduce the data saving spaces.

• The Journal of Korean Physical Therapy
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• v.23 no.6
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• pp.43-47
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• 2011

Purpose: The aim of this preliminary study was to use hand function tests to Hand dexterity levels provided by the type of compression garment and compression bandages in asymptomatic subjects and to collect baseline data for the comparison of hand functions in the patients with chronic arm lymphedema. Methods: The subjects of this study were 32 healthy volunteer female with a mean age of 45.8 years. Grip strength and hand functions were tested in three conditions-no compression, compression garment, and compression bandages-using the nine-hole peg test (NHPT), the box and block test (B&BT), Minnesota Manual Dexterity test (MMDT), and the hand-held Jamar dynamometer. Results: The grip strength was significantly low in the bandage condition (p<0.05). The performance in both compression groups (i.e., bandage and compression garment) decreased as the thickness of the compression material increased (p<0.05). Conclusion: The findings of this study suggest that grip strength and hand function scores are influenced by the characteristics of the compression applied. Future study is needed to determine the level of hand function between patients with chronic arm lymphedema and healthy individuals.

• Proceedings of the Korean Geotechical Society Conference
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• 1999.03a
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• pp.373-380
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• 1999

Consolidation settlements of soft clay are often large and potentially damaging to the structures. Currently, large-scale construction projects for airport and harbor etc. are in progress in Korea and many of these structures will be constructed on thick and soft clay layers. For this kind of ground condition, evaluation of consolidation settlement is required at every design and construction stages, and the magnitude of secondary compression appears to be larger than expected. Generally, the magnitude of secondary compression is evaluated by laboratory and in-situ consolidation tests or by empirical $C_{a/}$ $C_{c}$, relationship. The use of empirical value $C_{a/}$ $C_{c}$ may be economical, fast and powerful tool in estimating secondary consolidation settlement. However, the databases of the $C_{a/}$ $C_{c}$, for typical soft clays in Korea are insufficient. The purpose of this study is to investigate the relationship of $C_{a/}$ $C_{c}$ on marine clay near the southern sea in Korea. A series of incremental loading consolidation tests with measurement of pore water pressure were performed. It was found that the $C_{a/}$ $C_{c}$ of undisturbed marine clay is 0.0397. This value is similar to that proposed by Mesri and Castro(1987) on inorganic clay and silt. and silt. and silt.