• Restorative Dentistry and Endodontics
• /
• v.24 no.4
• /
• pp.614-622
• /
• 1999

Recent studies have implicated that more rostral components of the trigeminal spinal nucleus including subnucleus oralis (Vo) in orofacial nociceptive mechanisms. Since there is only limited electrophysiological evidence, the present study was initiated to characterize the receptive field and response properties of malls nociceptive neurons in chloralose/urethan-anesthetized rats. Single neuronal activity was recorded in right subnucleus oralis, and types of nociceptive neurons classified wide dynamic range (WDR), NS (nociceptive specific) and deep nociceptive (D) and the mechanoreceptive field (RF) and response properties were determined. A total of 34 nociceptive neurons could be subdivided into 17WDR neurons, 12NS neurons and 5D neurons. Vo nociceptive neurons had RF involving maxillary and/or mandibular divisions mainly located in the intraoral and/or perioral regions. Majority of Vo nociceptive neurons showed spontaneous activity less than 1Hz. The NS and D neurons activated only by heavy pressure and/or pinch stimuli had high mechanical thresholds compared to WDR neurons activated also by tactile stimuli. Vo nociceptive neurons showed a progressive increase of response to the graded mechanical stimuli. 39% of Vo nociceptive neurons received C-fiber electrical input as well as A-fiber electrical input from their RF, and 45% of them responded to electrical stimulation of the right maxillary first molar. 41% of Vo nociceptive neurons responded to noxious heat applied to their RF, and 18% of them showed an immediate burst of discharges following MO application to the right maxillary first molar pulp. These results indicate that Vo is involved in the transmission of nociceptive information mainly coming from intraoral or perioral region including tooth pulp.

• Restorative Dentistry and Endodontics
• /
• v.31 no.5
• /
• pp.344-351
• /
• 2006

The purpose of this study was to evaluate the thermal expansion characteristics of injectable ther-moplasticized gutta-perchas and a Resilon. The materials investigated are Obtura gutta-percha, Diadent gutta-percha, E&Q Gutta-percha Bar and Epiphany (Resilon). The temperature at the heating chamber orifice of an Obtura II syringe and the extruded gutta-percha from the tip of both 23- and 20-gauge needle was determined using a Digital thermometer. A cylindrical ceramic mold was fabricated for thermal expansion test, which was 27 mm long, with an internal bore diameter of 3 mm and an outer diameter of 10 mm. The mold was filled with each experimental material and barrel ends were closed with two ceramic plunger. The samples in ceramic molds were heated in a dilatometer over the temperature range from $25^{\circ}C$ to $75^{\circ}C$. From the change of specimen length as a function of temperature, the coefficients of thermal expansion were deter-mined. There was no statistical difference between four materials in the thermal expansion in the range from $35^{\circ}C$ to $55^{\circ}C$ (p > 0.05). However, Obtura Gutta-percha showed smaller thermal expansion than Diadent and Metadent ones from $35^{\circ}C$ to $75^{\circ}C$ (p < 0.05). The thermal expansion of Epiphany was similar to those of the other gutta-percha groups.

• The Journal of the Society of Stroke on Korean Medicine
• /
• v.13 no.1
• /
• pp.24-32
• /
• 2012

Object : The purpose of this study is to observe the correlation between change in pattern identification symptoms and scandinavian stroke scale in ischemic stroke patient who had receive traditional Korean medical treatment and conservative treatment. Methods : 43 subjects were recruited from patients with ischemic stroke within 30 days of onset. We chose the subjects who had at least one follow up session and had checked the score between last follow up session and first session in pattern identification and scandinavian stroke scale. We also assessed the correlation between pattern identification and scandinavian stroke scale. Results : There were significant negative correlation between pattern identification and scandinavian stroke scale in Fire-heat pattern and positive correlation in Dampness-phlegm pattern. Conclusions : This study provides evidence that collaborative treatment maybe effective in improving neurologic symptoms in ischemic stroke patients diagnosed as Fire-heat pattern. Further studies with larger scale and longer observation period, more neurologicscales scales, control group would be required.

• Restorative Dentistry and Endodontics
• /
• v.32 no.6
• /
• pp.522-529
• /
• 2007

The purpose of this study was to compare the apical leakage of the root canal filled with the System B and the EndoTwinn(the combined application of heat and ultrasonic vibration). Sixty extracted premolars with straight root were cleaned and shaped to size 35. Group SB was obturated using System B and Group ET was filled with EndoTwinn. A size 35 of 0.06 tapered gutta-percha and Adseal were used and the plugger which could be introduced to 4 mm short of working length was selected in the obturation procedure. As the positive control, Group PC was not filled. In Group SB, ET and PC, all external surfaces of each tooth were coated with nail varnish leaving only 1 mm area around the apical foramen. In the negative control of Group NSB and Group NET, all of external tooth surface including apical foramen was coated with the nail varnish. The specimens were immersed in methylene blue dye solution for 2 days. Then the specimens were sectioned at each 1 mm from apex to 5 mm level. The final score of one specimen was given by summing up of the points at all levels. The dye leakage of Group ET was significantly less than that observed in Group SB (p < 0.05). And the frequency of gutta-percha pulling out from root canal when the plugger was removed was more often with the System B than with EndoTwinn but there was no significant difference.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.19 no.1
• /
• pp.9-17
• /
• 2015

The basic flow configuration is composed of a plane, double shear layer where relatively thin mid gas layer is sandwiched between air and fuel stream. The present study describes numerical investigations concerning the combustion enhancement according to a variation of mid layer thickness. In this case, the effect of heat release in turbulent mixing layers is important. For the numerical solution, a fully conservative unsteady $2^{nd}$ order time accurate sub-iteration method and $2^{nd}$ order TVD scheme are used with the finite volume method including k-${\omega}$ SST model. The results consists of three categories; single shear layer consists of fuel and air, inert gas sandwiched between fuel and air, cold fuel gas sandwiched between fuel and air. The numerical calculations has been carried out in case of 1, 2, 4 mm of mid layer thickness. The height of total gas stream is 4 cm. The combustion region is broadened in case of inert gas layer of 2, 4 mm thickness and cold fuel layer of 4 mm thickness compared with single shear layer.

• Nuclear Engineering and Technology
• /
• v.41 no.10
• /
• pp.1263-1274
• /
• 2009

Several experimental tests to simulate a reflood phase of a cold-leg LBLOCA of the APR1400 have been performed using the ATLAS facility. This paper describes the related experimental results with respect to the thermal-hydraulic behavior in the core and the system-core interactions during the reflood phase of the cold-leg LBLOCA conditions. The present descriptions will be focused on the LB-CL-09, LB-CL-11, LB-CL-14, and LB-CL-15 tests performed using the ATLAS. The LB-CL-09 is an integral effect test with conservative boundary condition; the LB-CL-11 and -14 are integral effect tests with realistic boundary conditions, and the LB-CL-15 is a separated effect test. The objectives of these tests are to investigate the thermal-hydraulic behavior during an entire reflood phase and to provide reliable experimental data for validating the LBLOCA analysis methodology for the APR1400. The initial and boundary conditions were obtained by applying scaling ratios to the MARS simulation results for the LBLOCA scenario of the APR1400. The ECC water flow rate from the safety injection tanks and the decay heat were simulated from the start of the reflood phase. The simulated core power was controlled to be 1.2 times that of the ANS-73 decay heat curve for LB-CL-09 and 1.02 times that of the ANS-79 decay curve for LB-CL-11, -14, and -15. The simulated ECC water flow rate from the high pressure safety injection pump was 0.32 kg/s. The present experimental data showed that the cladding temperature behavior is closely related to the collapsed water level in the core and the downcomer.

• Nuclear Engineering and Technology
• /
• v.27 no.3
• /
• pp.344-357
• /
• 1995

The gap conductance between the fuel and the sheath depends strongly on the gap width and has a significant influence on the amount of initial stored energy. The modified Ross and Stoute gap conductance model in ELESTRES is based on a simplified thermal deformation model for steady-state fuel temperature calculations. A review on a series of experiments reveals that fuel pellets crack relocate, and are eccentrically positioned within the sheath rather than solid concentric cylinders. In this paper, the hue recently-proposed gap conductance models (offset gap model and relocated gap model) are described and are applied to calculate the fuel-sheath gap conductances under experimental conditions and normal operating conditions in CANDU reactors. The good agreement between the experimentally-inferred and calculated gap conductance values demonstrates that the modified Ross and Stoute model was implemented correctly in ELESTRES. The predictions of the modified Ross and Stoute model provide conservative values for gap heat transfer and fuel surface temperature compared to the offset gap and relocated gap models for a limiting power envelope.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.32 no.4
• /
• pp.215-222
• /
• 2019

The heat conduction problem with discontinuous material coefficients generally consists of the conservative equation, boundary condition, and interface condition, which should be additionally satisfied in the solution procedure. This feature often makes the development of new numerical schemes difficult as it induces a layered singularity in the solution fields; thus, a special approximation is required to capture the singular behavior. In addition to the approximation, the construction of a total system of equations is challenging. In this study, a wedge function is devised for enriching the approximation, and the interface condition itself is embedded in the moving least squares(MLS) derivative approximation to consistently satisfy the interface condition. The heat conduction problem is then discretized in a strong form using the developed derivative approximation, which is named as the interface immersed MLS difference method. This method is able to efficiently provide a numerical solution for such interface problems avoiding both numerical quadrature as well as extra difference equations related to the interface condition enforcement. Numerical experiments proved that the developed numerical method was highly accurate and computationally efficient at solving the heat conduction problem with interfacial jump as well as the problem with a geometrically induced interfacial singularity.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.29 no.9 s.240
• /
• pp.1049-1056
• /
• 2005

A conservative pressure-based finite-volume numerical method has been developed for computing flow and heat transfer by using an unstructured grid system. The method admits arbitrary convex polyhedra. Care is taken in the discretization and solution procedures to avoid formulations that are cell-shape-specific. A collocated variable arrangement formulation is developed, i.e. all dependent variables such as pressure and velocity are stored at cell centers. Gradients required for the evaluation of diffusion fluxes and for second-order-accurate convective operators are found by a novel second-order accurate spatial discretization. Momentum interpolation is used to prevent pressure checkerboarding and the SIMPLE algorithm is used for pressure-velocity coupling. The resulting set of coupled nonlinear algebraic equations is solved by employing a segregated approach, leading to a decoupled set of linear algebraic equations fer each dependent variable, with a sparse diagonally dominant coefficient matrix. These equations are solved by an iterative preconditioned conjugate gradient solver which retains the sparsity of the coefficient matrix, thus achieving a very efficient use of computer resources.

• Steel and Composite Structures
• /
• v.13 no.4
• /
• pp.309-325
• /
• 2012

The risk of progressive collapse in steel framed buildings under fire conditions is gradually rising due to the increasing use of combustible materials. The fire resistance of such steel framed buildings is evaluated by fire tests. Recently, the application of performance based fire engineering makes it easier to evaluate the fire resistance owing to various engineering techniques and fire science. The fire resistance of steel structural members can be evaluated by the comparison of the limiting temperatures and maximum temperatures of structural steel members. The limiting temperature is derived at the moment that the failure of structural member results from the rise in temperature and the maximum temperature is calculated by using a heat transfer analysis. To obtain the limiting temperatures for structural steel of grades SS400 and SM490 in Korea, tensile strength tests of coupons at high temperature were conducted. The limiting temperatures obtained by the tensile coupon tests were compared with the limiting temperatures reported in the literature and the results of column fire tests under four types of loading with different load ratios. Simple limiting temperature formulas for SS400 and SM490 steel based on the fire tests of the tensile coupons are proposed. The limiting temperature predictions using the proposed formulas were proven to be conservative in comparison with those obtained from H-section and hollow section column fire tests.