• Transactions of the Korean hydrogen and new energy society
• /
• v.26 no.3
• /
• pp.287-293
• /
• 2015

The current study has investigated the effects of biodiesel blended with gasoline on the spray characteristics in a Constant Volume Combustion Chamber (CVCC). With the concentration of 5, 10, 15 and 20% by volume, biodiesel was blended with commercial gasoline and performed on the macroscopic visualization test. Pure gasoline and biodiesel were also tested as the reference. The shadowgraph technique was conducted in the constant volume chamber. The spray images were recorded by a high speed video camera with frame speed 10,000 frame per second. Fuel injection was set at 800, 1000 and 1,350 bar with the simulated speed 1,500 and 2,000 rpm. The back pressure was controlled at 20 bar. The spray angle and penetration tip were measured and analyzed by using the image processing. At the high injection pressure, the spray penetration length with the simulated speed 1,500 rpm showed that B100 was lower than GB00-20 whereas the spray penetration length with the simulated speed 2,000 rpm exhibited that GB blends and B100 were insignificantly different. Due to biodiesel concentration, its effects on spray angles were observed throughout injection periods (T1, T2 and T3). At the simulated speed 1,500 rpm, the spray angle of GB blends and B100 presented the same pattern following injection timing. In addition, when the simulated speed increased to 2,000 rpm the different spray angle of all blends disappeared at main injection (T3).

• Journal of the Korean Society of Industry Convergence
• /
• v.10 no.2
• /
• pp.123-128
• /
• 2007

The demand for the precision rubber products has been rapidly increasing with the recent growth of industries. And the requirement for the productivity and the quality calls out for the injection molding machines with the precision machining ability as well as the high productivity. Especially modern automobile industry is in urgent need of developing injection molding machines for the high quality rubber products with high productivity. And the inability of the domestic companies to meet the standards causes importing foreign machines and as a result spending good amount of dollars. It is extremely important to develop competitive machines and strengthen the infrastructure of the related industries. In this paper the functions and the structure of a automatic multi-nozzle injection molding machine has been studied to set up a proper test system for the precision rate and the reliability of the machines, which can help build the machines to meet the request of the industry.

• The Journal of Engineering Geology
• /
• v.32 no.4
• /
• pp.643-659
• /
• 2022

Geologic sequestration technologies such as CCS (carbon capture and storage), EGS (enhanced geothermal systems), and EOR (enhanced oil recovery) have been widely implemented in recent years, prompting evaluation of the mechanical stability of storage sites. As fluid injection can stimulate mechanical instability in storage layers by perturbing the stress state and pore pressure, poroelastic models considering various injection scenarios are required. In this study, we calculate the pore pressure, stress distribution, and vertical displacement along a surface using commercial finite element software (COMSOL); fault slips are subsequently simulated using PyLith, an open-source finite element software. The displacement fields, are obtained from PyLith is transferred back to COMSOL to determine changes in coseismic stresses and surface displacements. Our sequential use of COMSOL-PyLith-COMSOL for poroelastic modeling of fluid-injection and induced-earthquakes reveals large variations of pore pressure, vertical displacement, and Coulomb failure stress change during injection periods. On the other hand, the residual stress diffuses into the remote field after injection stops. This flow pattern suggests the necessity of numerical modeling and long-term monitoring, even after injection has stopped. We found that the time at which the Coulomb failure stress reaches the critical point greatly varies with the hydraulic and poroelastic properties (e.g., permeability and Biot-Willis coefficient) of the fault and injection layer. We suggest that an understanding of the detailed physical properties of the surrounding layer is important in selecting the injection site. Our numerical results showing the surface displacement and deviatoric stress distribution with different amounts of fault slip highlight the need to test more variable fault slip scenarios.

• The Korean Journal of Pain
• /
• v.14 no.2
• /
• pp.176-180
• /
• 2001

Background: The aim of our study was to evaluate the antiemetic effects of intravenous dexamethasone in preventing continuously infused epidural morphine-related nausea and vomiting. Methods: Twenty-seven patients requiring general anesthesia for gastrectomy were enrolled in a randomized, double-blinded, and placebo-controlled study. At the end of surgery, all patients received epidural morphine 3 mg and were connected to an epidural morphine infusion pump for 2 days in order to relieve postoperative pain. Before the morphine injection, the dexamethasone group (n = 12) received IV dexamethasone 10 mg, whereas the saline group (n = 15) received IV saline. The incidence of nausea & vomiting, pruritus, back pain and VAS scores were assessed in the recovery room, and at 24 h and 48 h postoperatively. Results: There was no significant difference in the total incidence of nausea and vomiting, pruritus, back pain or in the VAS scores. However, there was no vomiting and no back pain in the dexamethasone group. Conclusions: Intravenous dexamethasone did not significantly decrease the total incidence of nausea or vomiting in patients receiving continuous epidural morphine for postoperative pain control. However, IV dexamethasone appears to decrease the severity of nausea, vomiting and back pain.

• Journal of Acupuncture Research
• /
• v.32 no.4
• /
• pp.203-211
• /
• 2015

Objectives : The purpose of this study was to assess the effectiveness of integrative Korean Medical treatments for patients with L-spine disk herniation that showed no response to Epidural Steroid Injections (ESI). Methods : In this study, we reviewed the medical records of ten patients who showed no improvement or relapsed after ESI. The patients each received more than three weeks of integrative treatments at Mokhuri Neck&Back Hospital. The Visual Analog Scale (VAS) and Oswestry Disability Index (ODI) was measured before and after treatment. A statistical analysis to compare before and after treatments was assessed using paired t-test the SPSS 12.0 Windows program. Results : After three weeks of treatment, patients showed a significant decrease in VAS and ODI scores compared to before receiving treatment. VAS scores decreased from $5.3{\pm}1.25$ to $1.9{\pm}0.99$ (p<0.001), and ODI scores decreased from $59.8{\pm}22.2$ to $32.7{\pm}14.11$ (p<0.001). Conclusions : Complex Korean Medical treatment showed effectiveness in the treatment of L-spine HIVD patients that showed no response to ESI, and more objective research is needed.

• Restorative Dentistry and Endodontics
• /
• v.14 no.2
• /
• pp.38-48
• /
• 1989

The purpose of this study was to investigate the proper consistency of root canal sealer needed in obtaining an efficient canal obturation in injection-thermoplasticized low-temperature ($70^{\circ}C$) gutta-percha method. The sealer was made by incorporating zinc oxide powder into $0.5m{\ell}$ of eugenol and then the $0.5m{\ell}$ of mixture slurry was placed between two flat glass plates. The consistency was determined by measuring the degree of spread of the slurry at loading the 120gm of weight from the top plate. The sealer was prepared according to P/L ratio corresponding to the acquired consistency of 65.45mm, 46.80mm, 28.95mm and 22.60mm. The distal roots were obtained by cutting off from 125 extracted human lower molars and the root canals were prepared by using step-back method. The prepared canals were coated with the sealers on their walls and obturated by using the injection-thermoplasticized low-temperature ($70^{\circ}C$) gutta-percha method. All specimens were immersed in 2% methylene blue dye solution for 48 hours at $37^{\circ}C$. Calipers was used to measured the dye penetration into the root canals from apical constrictions. The results were as follows : The canals obturated without sealer showed significantly more leakage than the canals obturated with sealer. Within the consistency from 65.45mm to 22.60mm, the sealer of 65.45mm appeared significantly better than that of 28.95mm and 22.60mm in the canals obturated by injection-thermoplasticized gutta-percha method, and better than that of 46.80mm without statistical significance.

• The Korean Journal of Pain
• /
• v.22 no.3
• /
• pp.229-233
• /
• 2009

Background: Sacroiliac (SI) joint pain is a challenging condition that causes lower back or buttock pain; however, there is no universally accepted long-term treatment. There have been several reports of ligament prolotherapy for SI joint pain, but these have had inconsistent results, probably due to the lack of a specific diagnosis for patient selection and variability in the volume, number and sites of injection. Therefore, this study was conducted to assess the efficacy of intraarticular prolotherapy for relieving SI joint pain diagnosed by local anesthetic intraarticular injection. Methods: Twenty-two patients with SI joint pain confirmed by 50% or more improvement in response to local anesthetic block underwent intraarticular prolotherapy with 25% dextrose water every other week three times. The numeric rating scale (NRS) for pain and Oswestry disability index (ODI) were assessed at the initial visit and after completion of a series of prolotherapy and the NRS was checked during monthly follow-up sessions to evaluate the long-term effectiveness of this technique. Results: Twenty patients completed prolotherapy and followed up as scheduled. The NRS and ODI were significantly improved from 6 (4-8) and $34.1{\pm}15.5$ to 1 (0-3) and $12.6{\pm}9.8$ (P < 0.01), respectively, at 1 month after prolotherapy. The mean duration of pain relief of 50% or more was 12.2 months (95% CI, 10.0-14.3) as determined by Kaplan-Meier survival analysis. Conclusions: Intraarticular prolotherapy provided long-term relief of sacroiliac joint pain and may have more benefits than ligament prolotherapy or neurolysis.

• The Korean Journal of Pain
• /
• v.19 no.2
• /
• pp.261-265
• /
• 2006

A vertebral compression fracture can cause chronic back pain, and may also result in progressive kyphosis. The traditional treatments of a vertebral compression fracture include bed rest, analgesics and bracing. Balloon kyphoplasty can restore the vertebral height and allow safe bone cement injection into the cavity made by the balloon, which significantly reduces the risk of cement leakage compared to vertebroplasty. An 82-year-old female patient suffered from severe low back pain. Due to the intractable pain and immobility, which could not be relieved by conventional care, as well as the empty vertebral body associated with communicated fractures of the vertebral surfaces, balloon kyphoplasty, with a thicker bone cement injection than usual with balloon kyphoplasty, was chosen. The preoperative intractable pain and immobility were dramatically relieved soon after the procedure, without any complications.

• The Korean Journal of Pain
• /
• v.4 no.2
• /
• pp.152-156
• /
• 1991

Cervical radiculopathy has been recognized as a common cause of neck, shoulder, and arm pain. It was conventionally treated with rest, traction, cervical collars, manipulation, transcutaneous electrical nerve stimulation, and nonsteroidal anti-inflammatory drugs with varying results. Surgery has not always been successful so the idea of epidural steroid injection was developed as in the case of lumbar epidural injections, for the treatment of low back pain and sciatica. Thirty one patients with evidence of cervical radiculopathy were treated with injections of triamcinolone acetate into the cervical epidural space. The effect of the steroid injection could be evaluated in twenty one patients who received epidural injections more than twice. No improvement was seen in 6 patients and 15 patients showed good to excellent pain relief for a week to over 6 months. Epidural steroid injection seems to have a positive role in the treatment of cervical radiculopathy.

• Journal of Pharmacopuncture
• /
• v.4 no.1
• /
• pp.65-84
• /
• 2001

We recently demonstrated that bee venom (BV) injection into acupoint (i.e. Zusanli) produced more potent anti-inflammatory and antinociciptive effect in Freunds adjuvant induced rheumatoid arthritis (RA) model as compared with that of non-acupoint injection(i.e back). However, the precise components underlying BV-induced antinociceptive and/or anti-inflammatory effects have not been fully understood. Therefore, we further investigated the anti-arthritic effect of BV after extracting the whole BV according to solubility (water soluble: BVA, ethylacetate soluble: BVE). Subcutaneous BVA treatment (0.9 mg/kg/day) into Zusanli acupoint was found to dramatically inhibit paw edema and radiological change (i.e. new bone proliferation and soft tissue swelling) caused by Freunds adjuvant injection. In addition, the increase of serum interleukin-6 by RA induction was normalized by the BVA treatment as similar with that of non-arthritic animals. On the other hand, BVA therapy significantly reduced arthritis induced nociceptive behaviors (i.e., nociceptive score for mechanical hyperalgesia and thermal hyperalgesia). Furthermore, BVA treatment significantly suppressed adjuvant induced Fos expression in the lumbar spinal cord at 3 weeks post-adjuvant injection. However, BVE treatment (0.05 mg/kg/day) has not any anti-inflammatory and anti-nociceptive effect on RA. Based on the present results, we demonstrated that BVA might be a effective fraction in whole BV for long-term treatment of RA-induced pain and inflammation. However, it is clear necessary that further fraction study about BVA was required for elucidating an effective component of BVA.