• Journal of Korean Neurosurgical Society
• /
• v.58 no.3
• /
• pp.304-307
• /
• 2015

Only a few cases of anterior longitudinal ligament (ALL) injury related with retropharyngeal hematoma without fracture have previously been reported. The treatment of choice for retropharyngeal hematoma is generally considered to be conservative care, but we believe that early surgery of this pathology would be better in certain situations. Here, we describe two cases with life-threatening large retropharyngeal hematomas related with ALL injuries and operated on at an early stage. Two previously healthy patients visited the emergency room with neck pain and dyspnea after falling. Serious neck swelling was observed and lateral neck X-ray showed severe widening of the prevertebral space. Due to dyspnea progression, emergency endotracheal intubation was performed. Although there was no primary cause of the retropharyngeal hematoma on preoperative examination, ALL tearing was intraoperatively confirmed during early surgery. The in-hospital evolutions of the patients were favorable after surgery. We should bear in mind the possibility of ALL injury and perform early surgery where possible given the earlier convalescence and good prognosis.

• Transactions of Materials Processing
• /
• v.14 no.1 s.73
• /
• pp.21-28
• /
• 2005

This paper is concerned with the quantitative effect of design parameters on a stamped part of the auto-body. The considered parameters in this paper are the blank holding force, the draw-bead force, the blank size which greatly affect the metal flow during stamping. The indicators of formability selected in this paper are failures such as tearing, wrinkling and the amount of springback. The stamping process of the front side inner member is simulated using the finite element analysis changing the design parameters. The numerical results demonstrate that the blank holding force cannot control the local metal flow during forming although it controls the overall metal flow. The modification of the initial blank size considering the punch opening line ensures the local wrinkling and reduces the amount of springback after forming. The restraining force of draw-bead controls the metal flow in the local area and reduces the amount of excess metal. It is noted that the parametric study of design parameters such as blank holding force, the blank size and the draw-bead are very important in the process design of the complicated member.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
• /
• 2010.04a
• /
• pp.195-206
• /
• 2010

Xylan can be applied to improve the strength properties of paper; however the optical properties, such as brightness, are decreased significantly. To solve that problem, an applicable bleaching process is therefore desired. The aim of this research was to investigate the impact of hydrogen peroxide bleaching on hardwood kraft pulp pretreated with birchwood xylan by measuring optical properties (whiteness, brightness, opacity) as well as physical properties (tensile index, tearing index, bulk) of handsheets made from the bleached pulp. Hydrogen peroxide bleaching, as a kind of totally chlorine free (TCF) bleaching method, is quite important industrially for chemical pulp. In our work, the process variables of peroxide bleaching including bleaching temperature, time, initial pH and $MgSO_4$ dosage were studied. The results showed that both good mechanical properties and optical properties could be achieved when the operating parameters were controlled properly and therefore hydrogen peroxide bleaching was proved to be a suitable method for bleaching hardwood kraft pulp with adsorption of birchwood xylan.

• Transactions of the Korean Society of Pressure Vessels and Piping
• /
• v.12 no.2
• /
• pp.34-39
• /
• 2016

This paper presents a method to quantify R-ratio effect on J-integral under large-amplitude cyclic loading condition. Generally, monotonic tearing resistance curves are used to assess stability of cracked nuclear piping under seismic loading. However, it is well known that fracture toughness decrease at cyclic loading condition, according to R-ratio. For this reason, it is important to quantify the J-R curves under cyclic loading condition. To quantify the R-ratio effect, correction method which was proposed by Tranchand is considered. This method considers crack opening area in order to calculate modified J-integral. This method leads to an increase of fracture toughness. At R=-0.5 case, this method is good agreement with monotonic J-R curves. However, results show that this method has a limit to apply a large R-ratio case.

• Journal of the Korean Applied Science and Technology
• /
• v.13 no.3
• /
• pp.137-144
• /
• 1996

Durable softening water repellents such as PODCW, PDDCW, and PEDCW were prepared by blending cationized polymers, fatty carbamide, waxes, and emulsifiers. The cationized polymers included poly (octadecyl methacrylate-co-2-diethylaminoethyl methacrylate) [PODC], poly (n-dodecyl methacrylate-co-2-diethylaminoethyl methacrylate) [PDDC]and poly (2-ethylhexyl methacrylate-co-2-diethylaminoethyl methacrylate) [PEDC]. After the PET fabrics were treated with these water repellents, water repellency, softness, and durability of the PET fabrics were examined by various methods : water repellency by the hydrostatic pressure and the contact angle methods, softness by crease recovery and tearing strength, and durability by washability, respectively. Rating of water repellency of PET fabrics treated with PODCW was $80^{+}$, but those treated with PDDCW and PEDCW were not high enough to be used in industry.

• Steel and Composite Structures
• /
• v.22 no.2
• /
• pp.353-368
• /
• 2016

This paper extends our recent work on the fatigue behavior of stud shear connectors in steel and recycled tyre rubber-filled concrete (RRFC) composite beams. A series of 16 fatigue push-out tests were conducted using a hydraulic servo testing machine. Three different recycled tyre rubber contents of concrete, 0%, 5% and 10%, were adopted as main variable parameters. Stress amplitudes and the diameters of studs were also taken into consideration in the tests. The results show that the fatigue lives of studs in 5% and 10% RRFC were 1.6 and 2.0 times greater of those in normal concrete, respectively. At the same time, the ultimate residual slips' values of stud increased in RRFC to highlight its better ductility. The average ultimate residual slip value of the studs was found to be equal to a quarter of studs' diameter. It had also been proved that stress amplitude was inversely proportional to the fatigue life of studs. Moreover, the fatigue lives of studs with large diameter were slightly shorter than those of smaller ones and using larger ones had the risk of tearing off the base metal. Finally, the comparison between test results and three national codes was discussed.

• Steel and Composite Structures
• /
• v.8 no.3
• /
• pp.179-200
• /
• 2008

This paper reports the results of a recent experimental study into the behavior of welded fin-plate connections to both hollow and concrete filled tubular (CFT) columns under shear. Experiments have been performed at both ambient and elevated temperatures with the aid of an electric kiln. The observed failure modes include fracture of the fin plate and tearing out of the tube around the welds. By considering the results of previously published research, the current design method for similar connections under purely tensile load, in CIDECT Guide 9, based on a deformation limit of 3% of the tube width is shown to be inadequate when evaluating the ultimate strength of such connections. By comparing the results from the current test program which failed in the fin-plate with Eurocode guidance for failure of a fin-plate alone under shear and bending load it is shown that the column face influences the overall connection strength regardless of failure mode. Concrete in-fill is observed to significantly increase the strength of connections over empty specimens, and circular column specimens were observed to exhibit greater strength than similarly proportioned square columns. A finite element (F.E.) model, developed using ABAQUS, is presented and validated against the experimental results in order that extensive parametric tests may be subsequently performed. When validating the model against elevated temperature tests it was found that using reduction factors suggested in published research for the specific steel grades improved results over applying the generic Eurocode elevated temperature steel strength reduction factors.

• Journal of Korean Neurosurgical Society
• /
• v.40 no.5
• /
• pp.384-386
• /
• 2006

Acute subdural hematoma is an exceptionally rare, but life-threatening complication of spinal anesthesia. The authors report here on a case of acute subdural hematoma in a 52-year-old male who underwent an arthroscopic knee joint operation under spinal epidural anesthesia due to tearing of the medial meniscus. He complained of headache after surgery. Computed tomography[CT] revealed acute subdural hematoma in the right fronto-tempo-parietal area. The headache progressed in spite of analgesics and bed rest; two weeks later, the CT showed subacute subdural hematoma with a mass effect. The patient improved after surgical decompression. The pathogenesis of subdural hematoma formation after dural puncture is discussed and we briefly review the relevant literature. Prolonged and severe postdural puncture headache[PDPH] should be viewed with suspicion and investigated promptly to rule out any intracranial complications. Immediate treatment of the PDPH with an epidural blood patch to prevent further CSF leakage should be considered.

• Journal of Korea Foundry Society
• /
• v.18 no.6
• /
• pp.570-577
• /
• 1998

An investigation has been conducted to describe solidification characteristics in Sn-Zn binary system and Sn-Zn-Ag ternary system added by Ag produced by the continuous casting process using heated mold as a basic study for developing Pb-free solder materials. To obtain the continuous casting rods with mirror surface and near net shape at higher casting speed, water flow rates must be increased and mold temperature must be lowered. However, surface tearing in the casting rods occured at lower continuous casting speed while break out occured at higher continuous casting speed even if optimum conditions such as water flow rate and heated mold temperature are determined. Primary ${\alpha}Sn$ and eutectic structure in unidirectioally solidified Sn-Zn alloys were finer with increased casting speed. But, directionality may not be expected for primary Zn in hypereutectic Sn-Zn alloy. It was found that the addition of $0.2{\sim}0.8%$ Ag promoted the growth of primary ${\alpha}Sn$ dendrites. The changes of tensile strength and elongation in Sn-Zn binary alloys were not observed while the increase of tensile strength and the decrease of elongation in Sn-Zn-Ag ternary alloys were observed with increased casting speed.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.44 no.2
• /
• pp.1-7
• /
• 2012

Hanji made of mulberry fibers has the lower printability due to their long fiber length, the diffusible property of ink, and low smoothness. This study was carried out to analyze the physical and optical properties of machine-made Hanji controlled by the different contents of paper mulberry 20, 40, 60, 80 and 100%. In this study, the results of comparing machine-made Hanji controlled by the different contents of $Paper$ $mulberry$ with commercial paper and inkjet coated paper are as following: Tearing strength of machine-made Hanji is higher than domestic paper and inkjet coated paper. By increasing paper mulberry contents of machine-made Hanji appeared that tensile strength increased and smoothness gradually decreased. Printability of machine-made Hanji is less than domestic paper and inkjet coated paper. However, there were significant possibility to use for printing paper.