• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.1
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• pp.23-31
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• 2011

At supercritical pressure, the physical properties of fluid change substantially and the heat transfer at a temperature similar to the critical or pseudo-critical temperature improves considerably; however, the heat transfer may deteriorate due to a sudden increase in the wall temperature at a certain condition of a mass and heat flux. In this study, the heat transfer rates in $CO_2$ flowing vertically upward and downward in a circular tube with a diameter of 4.57 mm under various conditions were calculated by measuring the temperature of the outer wall of the tube. The published heat transfer correlations were analyzed by comparing their prediction values with 7,250 experimental data. By introducing a buoyancy parameter, a heat transfer correlation, which could be applied only to a normal heat transfer regime, was extended such that it can be applied to regime of heat transfer deterioration. The published criteria for heat transfer deterioration were evaluated against the conditions obtained from the experiment in this study.

• Journal of the Mineralogical Society of Korea
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• v.15 no.3
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• pp.205-220
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• 2002

The gold-silver deposits in the Casado district were formed in the sheeted and stockwork quartz veins which fill the fault fractures in volcanic rocks. K-Ar dating of alteration sericite (about 70 Ma) indicates a Late Cretaceous age for ore mineralization. These veins are composed of quartz, adularia, carbonate, and minor of pyrite, sphalerite, chalcopyrite, galena, Ag-sulfosalts (argentite, pearceite, Ag-As-Sb-S system), and electrum. These veins are characterized by chalcedonic, comb, crustiform and feathery textures. Based on the hydrothermally altered mineral assemblages, regional alteration zoning associated with mineralization in the Gasado district is defined as four zones; advanced argillic (kaolin mineral-alunite-quartz), argillic (kaolin mineral-quartz), phyllic (quartz-sericite-pyrite) and propylitic (chlorite-carbonate-quartz-feldspar-pyroxene) zone. Phyllic and propylitic zones is distributed over the study area. However, advanced argillic zone is restricted to the shallow surface of the Lighthouse vein. Compositions of electrum ranges from 14.6 to 53.7 atomic % Au, and the depositional condition for mineralization are estimated in terms of both temperature and sulfur fugacity: T=245。$~285^{\circ}C$, logf $s_2$=$10^{-10}$ ~ $10^{-12}$ Fluid inclusion and stable isotope data show that the auriferous fluids were mixed with cool and dilute (158。~253$^{\circ}C$ and 0.9~3.4 equiv. wt. % NaCl) meteoric water ($\delta^{18}$ $O_{water}$=-10.1~8.0$\textperthousand$, $\delta$D=-68~64$\textperthousand$). These results harmonize with the hot-spring type of the low-sulfidation epithermal deposit model, and strongly suggest that Au-Ag mineralization in the Gasado district was formed in low-sulfidation alteration type environment at near paleo-surface.

• Journal of Korean Neurosurgical Society
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• v.30 no.5
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• pp.575-580
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• 2001

Purpose : In general, pineal region tumors are managed by using microsurgical approach or stereoctactic biopsy. However, in selected cases endoscopic approach to pineal lesions might prove to be as effective as microsurgery and less invasive. We report an alternative surgical strategy for managing certain patients with pineal neoplasms that allows treatment of the symptomatic hydrocephalus as well as tumor biopsy under direct vision in the same sitting. Materials and Methods : Twenty-two patients with pineal region tumors with associated hydrocephalus were treated in one session by endoscopic third ventriculostomy and endoscopic tumor biopsy at our institution from October 1996 to January 2000. All patients were retrospectively evaluated. Results : There was no operative mortality. There was one cause of significant bleeding during biopsy, but was controlled endoscopically, and the patient recovered completely without neurologic deficit resulting from intra-operative bleeding. The symptoms related to increased intracranial pressure(ICP) have resolved in all patients, and the need for a shunt is completely eliminated. Histological diagnosis was achieved in 21 of the 22 patients by this procedure. A biopsy was not obtained in one patient. Although this pineal region tumor was seen endoscopically, this could not be biopsied because of technical difficulties in working around an enlarged massa intermedia. The lesions included fourteen germinomas, three mixed germ cell tumors, and one each of the followings: pineocytoma, pineoblastoma, pineocytoma/pineoblastoma(intermediate type), meningioma, and low grade glioma. Five of the 22 patients subsequently underwent formal microsurgical tumor removal. Additional chemotherapy or radiotherapy could then be initiated according to the histological diagnosis. Conclusion : We consider that endoscopy affords a minimally invasive way of reaching three objectives by one-step surgery in the management of pineal region tumors with associated hydrocephalus : 1) cerebrospinal fluid(CSF) sample for analysis of tumour markers and cytology, 2) treatment of hydrocephalus by third ventriculostomy, and 3) several biopsy specimens can be obtained identifying tumors which will require further open surgery or adjuvant radiation and/or chemotherapy. However, complications and morbidities should be emphasized so as to be avoided with further technical experience.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.8
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• pp.8-13
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• 2018

Nitrogen oxides (NOx) have recently been very influential in the generation of ultrafine dust, which is of great social interest in terms of improving the atmospheric environment. Nitrogen oxides are generated mainly by the reaction of nitrogen and oxygen in air in a combustion gas atmosphere of high temperature in a combustion apparatus such as thermal power generation. Recently, research has been conducted on the combustion that recirculates the exhaust gas to the cylindrical burner by using a piping using a Coanda nozzle. In this study, three types of burners were carried out through computational fluid analysis. Case 1 burner with the outlet of the combustion gas to the right, Case 2 burner with both sides as gas exit, Case 3 burner with left side gas exit. The pressure, flow, temperature, combustion reaction rate and distribution characteristics of nitrogen oxides were compared and analyzed. The combustion reaction occurred in Case 1 and Case 2 burner in the right direction with combustion gas recirculation inlet and Case 3 burner in the vicinity of mixed gas inlet. The temperature at the outlet was about $100^{\circ}C$ lower than that of the other burners as the Case 2 burner was exhausted to both sides. The NOx concentration of Case 1 burner at the exit was about 20 times larger than that of the other burners. From the present study, it could be seen that it is effective for the NOx reduction to exhaust the exhaust gas to both side gas exits or to exhaust the exhaust gas to the opposite direction of inlet of recirculation gas.

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.2
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• pp.211-218
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• 2016

This study evaluated the effect of Candida norvegensis (C. norvegensis) viable yeast culture on in vitro ruminal fermentation of oat straw. Ruminal fluid was mixed with buffer solution (1:2) and anaerobically incubated with or without yeast at $39^{\circ}C$ for 0, 4, 8, 16, and 24 h. A fully randomized design was used. There was a decrease in lactic acid (quadratic, p = 0.01), pH, (quadratic, p = 0.02), and yeasts counts (linear, p<0.01) across fermentation times. However, in vitro dry matter disappearance (IVDMD) and ammonia-N increased across fermentation times (quadratic; p<0.01 and p<0.02, respectively). Addition of yeast cells caused a decrease in pH values compared over all fermentation times (p<0.01), and lactic acid decreased at 12 h (p = 0.05). Meanwhile, yeast counts increased (p = 0.01) at 12 h. C. norvegensis increased ammonia-N at 4, 8, 12, and 24 h (p<0.01), and IVDMD of oat straw increased at 8, 12, and 24 h (p<0.01) of fermentation. Yeast cells increased acetate (p<0.01), propionate (p<0.03), and butyrate (p<0.03) at 8 h, while valeriate and isovaleriate increased at 8, 12, and 24 h (p<0.01). The yeast did not affect cellulolytic bacteria (p = 0.05), but cellulolytic fungi increased at 4 and 8 h (p<0.01), whereas production of methane decreased (p<0.01) at 8 h. It is concluded that addition of C. norvegensis to in vitro oat straw fermentation increased ruminal fermentation parameters as well as microbial growth with reduction of methane production. Additionally, yeast inoculum also improved IVDMD.

• Asian-Australasian Journal of Animal Sciences
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• v.33 no.7
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• pp.1096-1102
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• 2020

Objective: An experiment was conducted to evaluate the effects of Lonicera japonica extract (LJE) on milk production, rumen fermentation and blood biomarkers of energy metabolism, inflammation and oxidative stress during the perinatal period of Holstein dairy cows. Methods: Eighteen Holstein dairy cows were used in a complete randomized design experiment with 3 dietary treatments and 6 cows per treatment. All cows received the same basal total mixed ration (TMR) including a prepartal diet (1.35 Mcal of net energy for lactation [NE_L]/kg of dry matter [DM], 13.23% crude protein [CP]) from -60 d to calving and a postpartal diet (1.61 Mcal of NE_L/kg of DM, 17.39% CP) from calving to 30 days in milk (DIM). The 3 dietary treatments were TMR supplemented with LJE at 0 (control), 1 and 2 g/kg DM, respectively. LJE was offered from 21 d before calving to 30 DIM. Dry matter intake (DMI) and milk production were measured daily after calving. Milk and rumen fluid samples were collected on 29 and 30 d after calving. On -10, 4, 14, and 30 d relative to calving, blood samples were collected to analyze the biomarkers of energy metabolism, inflammation and oxidative stress. Results: Compared with control diet, LJE supplementation at 1 and 2 g/kg DM increased DMI, milk yield and reduced milk somatic cell count. LJE supplementation also decreased the concentrations of blood biomarkers of pro-inflammation (interleukin-1β [IL-1β], IL-6, and haptoglobin), energy metabolism (nonesterified fatty acid and β-hydroxybutyric acid) and oxidative stress (reactive oxygen metabolites), meanwhile increased the total antioxidant capacity and superoxide dismutase concentrations in blood. No differences were observed in rumen pH, volatile fatty acid, and ammonia-N (NH₃-N) concentrations between LJE supplemented diets and the control diet. Conclusion: Supplementation with 1 and 2 g LJE/kg DM could increase DMI, improve lactation performance, and enhance anti-inflammatory and antioxidant capacities of dairy cows during perinatal period.

• Asian-Australasian Journal of Animal Sciences
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• v.2 no.2
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• pp.115-121
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• 1989

A comparative slaughter feeding experiment with steer calves weighing 280 kg and a concurrent digestion trial with wether lambs was conducted to study the energy value of rice straw as influenced by ammonia treatment and mixing with alfalfa hay. Steers were ad libitum fed one of nine completely mixed experimental diets: basal (high concentrate); 25 or 50% of untreated rice straw (URS) or ammoniated (plastic covered bales, 4.6% $NH_3$ by weight) rice straw (ARS) proportionately replacing part of the basal; a 50:50 % mixture of URS or ARS and alfalfa replacing a proportion of the basal at 25 and 50%. Digestibility of the nine complete diets (pelleted to prevent sorting) was determined with four ad libitum fed lambs. Ammoniation increased crude protein level (from 3.6 to 10.8%) and in vitro dry matter digestibility of the rice straw by 15%. The improvement in DE, NEm and NEg by ammoniation of rice straw was 20, 52 and 117%, respectively. Ammoniation of rice straw fed as 50% of the diet improved gains over the diet containing 50% URS, but no significant influence on animal performance was observed when rice straw was fed at the 25% level. Each 10% addition of URS to basal diet decreased empty body gain of steers by 116 gram per day compared with a decrease of 70 gram per day when rice straw had been ammoniated. There was no beneficial effect of ammoniation when the roughage component of the diet was a 50:50 mixture of rice straw and alfalfa. Ammoniation of straw and inclusion of alfalfa generally increased the concentration of total volatile fatty acids in rumen fluid. Ammoniation resulted in reduced concentrations of acetic and propionic acid, but increased concentration of butyric acid. Digestibility of URS was improved by mixing with alfalfa. However, alfalfa hay did not influence digestibility of ARS. Diets in which ARS replaced the basal mixture at 25 and 50% had higher NEm and NEg values than comparable URS diets. The same pattern was observed in the straw: alfalfa mixtures, but differences between URS and ARS were significant only for the 50% roughage diets.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.1
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• pp.39-43
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• 2003

Dietary fatty acid including mainly palmitic acid and stearic acid was fed to fattening cattle and its effect on body weight gain, plasma lipid contents and rumen liquid fermentation in vitro was examined. In expt. 1, the effect of dietary fatty acid on body weight gain and plasma lipid concentrations was examined. In the control diet group, cattle were fed 1 kg/day of rice straw and concentrate which satisfied the requirement. In the fatty acid group, cattle were given 250 g/d of fatty acid with the same diet of the control diet group. In the excess concentrate group, cattle were given the same diet of the control diet group plus 735 g/d of concentrate corresponding to the same TDN of 250 g/d of fatty acid. Diets were given for 7 days. Body weight gain of cattle given dietary fatty acid was significantly greater than that of cattle fed only rice straw and concentrate. When dietary fatty acid was added to cattle feed, plasma NEFA and HDL-cholesterol concentrations increased. In expt. 2, the influence of dietary fatty acid on gas production and VFA profile in the rumen liquid was investigated in vitro. In the control group, 10 mg of rice straw and 90 mg of concentrate were incubated in the rumen fluid. In the excess concentrate group, 10 mg of rice straw and 97.5 mg of concentrate were incubated. In the fatty acid group, 10 mg of rice straw, 90 mg of concentrate and 2.5 mg of fatty acids were incubated. The rumen liquid mixed with feed materials was incubated for 24 h and the cumulative gas volume was measured. The VFA profile was also measured. Cumulative gas volume in the rumen liquid with fatty acid was equal to the control. Excess concentrate increased cumulative gas volume compared to the fatty acid group. There was no significant difference in total VFA concentration between experimental diet groups. It is suggested that dietary fatty acid has the potency to improve growth performance in fattening cattle without failure in rumen fermentation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.5
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• pp.16-21
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• 2017

The aim of this study was to utilize ferronickel slag produced in the manufacture of stainless steel as a flowable backfill material for underground use using crushed fine powder. Experimental combinations were made using two components: Case A (sand) and Case B (soil). The optimal mixing ratio of Case A was sand (58.4%), ferronickel slag fine powder (21.6%), cement (1.8%), and water (18.2%). In the case of B, the optimal mixing ratio was determined to be soil (53.0%), ferronickel slag fine powder (20.0%), cement (1.7%), and water (25.3%). The uniaxial compressive strength of case A, which is a mixture of ordinary sand and ferronickel slag powder, was relatively larger than that of case B using soil. In addition, the strength of the specimen increased with increasing curing time. The uniaxial compressive strength tended to increase with increasing curing time. In addition, the unconfined compression strength of the fluid backfill material using common sand as the main material was relatively larger than that of the mixed material using soil as the main material. In case A, the uniaxial compressive strength ranged from 0.17-0.33 MPa, 0.21-0.39 MPa, and 0.19-0.40 MPa, respectively, at curing times of 7, 14, and 28 days. From the experimental results, it was concluded that the ratio of FNS powder and cement mixture was the most appropriate for Case A3. Case B, which used soil as the main material, showed a similar tendency to Case A. As a result of the dissolution test for evaluating the environmental harm of the FNS fine powder, there was no dissolution of substances harmful to the environment.

• Journal of the Korean Arthroscopy Society
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• v.17 no.1
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• pp.38-43
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• 2013

Purpose: To evaluate the efficiency of arthroscopic treatment for infected total knee arthroplasty (TKA), and to investigate the factors affecting the outcomes. Materials and Methods: We analyzed 17 cases which underwent arthroscopic treatment to treat infection after TKA. After confirming infection by hematologic examination and analysis of joint fluid, we performed arthroscopic debridement, synovectomy and irrigation with normal saline mixed with antibiotics. Through routine examination after operation, we checked failure of treatment or recurrence of infection. If there is no recurrence until 2 years after the operation, we considered it as a success of treatment. Results: Of the 17 cases taken arthroscopic treatment, 13 cases were treated successfully with primary arthroscopic treatment only, but 4 cases had to undergo re-operation because of persistence or recurrence of infection. Analyzing the factors affecting the results, we found that symptom duration of the re-operation group is longer than the treated group after arthroscopy (p<0.05). Conclusion: Arthroscopic treatment can be effective when we performed appropriate selection of patients, careful and extensive arthroscopic irrigation and debridement, and suitable use of antibiotics. However, we have to do early arthroscopic surgery as soon as possible when infection after TKA is suspected.