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Roll forming has been widely used to produce steel sheet with low formability such as Ultra High Strength Steel (UHSS). It allows the steel sheet to be formed through successive bending process into a desired shape which even cannot be formed by press brake forming. Although the process effectively improves the formability of UHSS, there still the remains accuracy issue such as springback, flair, bow and so on. Especially, springback of UHSS is one of the major challenges in roll forming process as much as press forming process. In this paper, the springback of 1.5 GPa grade steel in roll forming process was numerically investigated for automotive sill-side inner component. The material behavior was described by using the selected hardening models: isotropic hardening (Piecewise linear model), linear kinematic hardening (Prager model [6]), nonlinear kinematic hardening model (Yoshida-Uemori model [7]). A commercial software LS-DYNA was utilized for the analysis. Eighteen successive roll stages were modelled for the simulation. From the results, it was found that the springback prediction during roll forming process could be successfully achieved when the complicated material behaviors including Bauschinger effect, nonlinear transient hardening, and changeable unloading modulus are taken into account for the Finite Element (FE) simulation.

To simulate a complicated hydrodynamic phenomena in the surf zone, the SWASH model is used in Haeundae Beach. The SWASH model is well known as a model competing with the Boussinesq-type model in terms of near shore waves and wave-induced currents modelling. This study is aimed to the detailed analysis of seasonal waves and wave-induced current simulation in Haeundae Beach, where the representative seasonal wave conditions was obtained from hourly measured wave data in 2014 by Korea Hydrographic and Oceanographic Administration( KHOA). Incident wave conditions were given as irregular waves by JONSWAP spectrum. The calculated seasonal wave-induced current patterns were compared with the field observation data. In summer season, a dominant longshore current toward the east of the beach appears due to the effect of incident waves from the South and the bottom bathymetry, then some rip currents occurs at the central part of the beach. In the winter season, ESE incident waves generates a strong westward longshore currents. However, a weak eastward longshore currents appears at the restricted east side areas of the beach.

Although ultra-high strength steel (UHSS) sheets with tensile stress above 1.0 GPa have a great attention in the automotive industries for reducing the weight and improving fuel efficiency of auto-body, the poor formability of UHSS sheets is one of the main factors hindering their industrial application. Enhancing the formability is a very important and challenging problem to both automotive and manufacturing engineers. In this study, the electro-plastic effect, which is first discovered in 1960s, of ultra-high strength steel sheets is investigated to improve the formability. To begin with, a test system is built up to carry out the tensile test with heavy electric current flowing through the specimen. The evolutions of the flow stress and the electric resistivity are obtained using this test system. The significant decrease in the flow stress caused by the heavy flowing through current is observed.

In this study, a Hydro Co-Extrusion Process of Al-Mn/Al-Si hybrid alloys prepared by electromagnetic duo-casting was investigated. Sleeve of the duo-casted billets is 3003 Al-Mn alloy and core is 4004 Al-Si alloy. It is expected hydrostatic stress during the HCE process enhances formability of materials and minimize any defects in extruded billets due to different material properties between two Al alloys. The duo-casted billet was extruded at temperature of 423K and with extrusion ratio of 5. Finally, the effect of the HCE on microstructure of the billet was investigated by an optical microscope.

In this study, the variation of workability of semi-continuously casted and extruded ZK60A magnesium alloy was investigated. To determine the deformation capability of two different billets, uniaxial compression tests were conducted at elevated temperatures and two different strain rates. In addition, the microstructural evolution was investigated using electron backscatter diffraction (EBSD) to compare the microstructure before and after the extrusion. The formability of ZK60A depending on the microstructure is discussed based on the experimental results obtained in this study, and is compared with earlier research in the literature.

Red Liriope platyphylla (RLP) manufactured by two repeated steps (steaming and drying) stimulates the insulin secretion ability and glucose receptor signaling pathway in an animal model for type I diabetes. This study examined the levels of glucose and lipid metabolism-related factors in a useful animal model for type II diabetes with obesity following RLP treatment for 3 weeks to determine if RLP treatment affects the glucose concentration, insulin secretion and fatty acid oxidation. The following results were obtained: i) RLP contained a large amount of polyphenolic compounds; ii) insulin secretion was induced in RLP-treated OLETF rats, although there were no significant differences in body weight, glucose tolerance test and glucose concentration; iii) the RLP-treated OLETF rats showed a significant increase in adiponectin concentration but the concentration of triglyceride and LDL decreased compared to the vehicle-treated rats; iv) although the abdominal fat mass and adipocyte size did not change with RLP treatment, expression of the adipocyte marker genes and β-oxidation genes in fat tissue was recovered to the level of the LETO rats; v) fatty liver formation was reduced dramatically in the liver of the RLP-treated group compared to the vehicle-treated group; vi) the expression of adipocyte marker genes and the β-oxidation gene in the liver tissue were generally similar to those of the abdominal fat but PPAR-γ showed a reverse pattern in the RLP- and vehicle-treated OLETF rats. These results suggest that RLP may stimulate insulin secretion and a decrease in lipid in serum, and may also suppress fatty liver formation through the regulation of fatty acid oxidation. The data presented here highlight the possibility that RLP can be considered a candidate for the prevention or alleviation of obesity-related diseases.

Laser forming involves heating sheet metal workpiece along a certain path with a defocused laser beam directed irradiate to the surface. During laser forming, a transient temperature fields is caused by the irradiation and travelling of a laser beam. Consequently, thermal expansion and contraction take place, and allows the thermal-mechanical forming of complex shapes. This is a new manufacturing technique that forming metal sheet only by thermal stress. Therefore, the analysis of temperature fields and stress fields are very useful for studying the forming mechanism and controlling the accuracy of laser forming. The non-liner finite element solver, ABAQUS, is employed to solve the thermal-mechanical analysis. Using this model, the temperature and stress distribution of DP980 are analyzed. Numerical results agree well with the experimental results.

This research explores the micro-forming process of spiral groove pattern on Fluid Dynamic Bearing(FDB), which is utilized in precision driving part of the hard disk drive(HDD), using micro desktop forming system. While EDM and ECM process has been widely used to engrave the precision pattern which generates dynamic pressure on FDBs, micro forming process is newly proposed in this study to increase the productivity and to reduce the product costs. At first, desktop forming system is designed for spiral groove pattern forming. FE simulations are followed in order to evaluate the feasibility of micro-forming. The simulation results show that forming loads of 1,500Kgf is required to fabricate micro patterns with the depth of 15 μm. Finally the formability test is carried out with various forming loads. Deformed shapes and forming loads obtained from the test are compared with those from the analysis. The results fully demonstrate that micro pattern forming techniques are available to fabricate micro spiral groove patterns in FDB.

AZO (Aluminum doped Zinc Oxide) is widely used to produce transparent conductive coatings for liquid crystal displays, flat panel displays, plasma displays, touch panels, and electronic ink applications. The densification behavior of AZO powder is a critical factor related to the design of the compaction process. In this study, the densification behavior of AZO powder during cold compaction has been investigated in order to calibrate the modified Drucker-Prager Cap (DPC) model for FE simulations. A compaction test with a cylindrical die was carried out, and two failure tests were performed: the diameteral compression test and the uniaxial compression test. AZO compacts with various densities from the compact tests were used as specimens for the failure tests. Based on the experimental results, the parameters of the modified DPC model were determined through simple manipulations.

In this paper, finite element analyses of thread rolling process for the micro-sized screw with the diameter of 800 μm and the thread pitch of 200 μm are firstly carried out. For the finite element analysis of the thread rolling process, hardening behavior of SUS has been estimated by the compression and tensile tests. And then, process design has been conducted with the aid of simulations and the prototype of the micro screw finally has been fabricated. In order to verify the CAE based process design for micro-sized screws, the deformed shape and dimensions obtained from the CAE are compared with those from the experiment. The deformed shapes of the pitch part and the top part of threads can be demonstrated the feature of experimental result.

In this study, we isolated and characterized plant-associated lactic acid bacteria which are able to produce angiotensin-converting enzyme (ACE) inhibitory and antioxidative activities. Five lactic acid bacteria were isolated from plants (grape and leek), a plant-associated fermentative product (Kimchi) and Korean traditional alcohol (Dongdongju). Strains K-1 and K-21 from Kimchi, strain L-5 from leek, strain G-3 from grape, and strain D-3 from Dongdongju were identified as Pediococcus pentosaceus, Lactobacillus plantarum, Weissella cibaria, L. plantarum, and L. brevis, respectively, by 16S rRNA gene analysis. ACE inhibitory activities of isolated strains ranged from 44.3 to 71.9% in the MRS broth. G-3, L-5 and K-1 strains especially showed high ACE inhibitory activities (59.8-98.69%) in the MRS broth containing skim milk. DPPH radical scavenging activities of the strains were in the range of 42.5-82.7%. All strains showed varying levels of resistance in artificial gastric fluid (pH 2.5), retaining viability ranging from 42.2 to 88.1% after 3 hr of incubation. All strains showed high resistance to 0.3% oxgall after 24 hr of incubation; survival rates were in the range of 55.4-112.8%. Isolated strains were found to be antagonistic to some pathogens including Pseudomonas aeruginosa.

In this paper, we discuss the problem of the input-output linearization method for the time-varying nonlinear systems with model uncertainties. The uncertainty of model is presented in all systems, the primary concern in the system analysis. In particular, in this study, while proving the input-output linearization theorem for time-varying nonlinear systems with uncertainty, the uncertainty bounded range of models is derived. It can be seen that the expansion of the input-output linearization for the time-invariant nonlinear system with uncertainty. The Algorithm is simulated and tested by MATLAB. The results show that this algorithm which is more effective routing protocol prolongs the network lifetime.

This paper is concerned with hole flangeability of steel sheet, which is evaluated by experiment and finite element analysis with respect to the hole processing condition. The hole flangeability of a material as a forming limit needs to be verified to predict and prevent the undesirable fracture during a flanging process. Hole expanding tests are carried out to identify the effect of hole processing conditions on the hole expanding ratio (HER), which is an indicator of the hole flangeability. Specimens with two different hole conditions are prepared: one is produced with punching process; and the other is reamed after punching to get smoother hole surface. Experimental results show that the facture mechanism and the HER are quite different with respect to the hole conditions. Thorough investigation of those effects is carried out with tensile tests of a specimen with notches. From the experiments, the fracture strain is obtained with different hole conditions and is used to determine the material constants of a new proposed ductile fracture criterion which is applied to finite element analyses of the hole flanging process for prediction of the HER. The experimental results are confirmed and reevaluated by the finite element analysis with the ductile fracture criterion.

For 5.0, 20.5, 50.0, and 75.0 mass % methyldiethanolamine (MDEA) aqueous solutions, solubilities of CO2 were measured at 323.15, 348.15, and 373.15 K, respectively. Isothermal absorption capacities of CO2 as a function of MDEA concentration are presented. Lastly, the absorption enthalpy of CO2 in 50.0 mass % MDEA solution was calculated to be 54 kJ·mol-1 CO2.

An elasto-plastic finite element method is adopted to simulate draw-bead formation and draw-in process through the draw-bead. The finite element method code has to deal with a proper contact algorithm and a stress evaluation algorithm, since the sheet metal undergoes large deformation and rotation with severe geometric changes. The simulation of draw-bead formation produces the distribution of stress and strain in deformed sheet metal along the bead as well as the punch force of a draw-bead. It also provides the resultant elongation of the sheet in the cavity region, which is the fundamental information as a boundary condition to analyze the complicated binder-wrap phenomena.

BACKGROUND/AIMS The purpose of this study was to estimate the prevalence of Barrett's esophagus (BE) and its association with reflux esophagitis (RE) and peptic ulcer disease detected by free charge endoscopy which was covered by the National Health Insurance at a secondary care hospital, and to compare the results of the biopsy of BE with that of cardiac intestinal metaplasia (CIM). METHODS A total of 4,002 patients underwent endoscopy from March 2010 to December 2012. BE was diagnosed if there was histologically proven specialized intestinal metaplasia, and CIM was diagnosed if intestinal metaplasia was accompanied with chronic gastritis. RESULTS Four hundred twenty four patients underwent endoscopic biopsy, and the prevalence of BE was 1.0% (42/4,002). The mean age and the proportion of males in BE were significantly higher than those of the rest of study population, and BE had slight tendency related to RE than the rest of study population. CIM was observed in 34 patients and BE and CIM showed similar results, regarding age, sex and association with RE. The mean length of endoscopic Barrett's mucosa of BE group was 9.2±5.1 mm, and it was similar to that of CIM. CONCLUSIONS The prevalence of BE in the secondary care hospital was not low, and old age and male sex were significantly associated with BE. Because BE was observed in about 10% of biopsied patients and CIM was observed in a similar percentage with BE, the precise targeted biopsy is warranted and the biopsy method should be reestablished through the large prospective study of multiple secondary care hospitals.

The herb Liriope platyphylla (LP) has been considered to have curative properties for diabetes, asthma and neurodegenerative disorders. To examine the effects of steaming time and frequency of manufactured red LP (RLP) on the nerve growth factor (NGF) secretion ability and NGF receptor signaling pathway, the NGF concentration, cell differentiation, NGF signaling pathway and calcium concentration were analyzed in neuronal cells treated with several types of LPs manufactured under different conditions. The maximum NGF secretion was observed in B35 cells treated with 50 µg/ml LP extract steamed for 9 h (9-SLP) and with two repeated steps (3 h steaming and 24 h air-dried) carried out 7 times (7-SALP). No significant changes in viability were detected in any of the cells treated with the various LPs, with the exception of 0-SLP and 0-SALP. In addition, PC12 cell differentiation was induced by treatment with the NGF-containing conditional medium (CM) collected from the RLP-treated cells. The levels of TrkA and extracellular signal-regulated kinase (ERK) phosphorylation in the high affinity NGF receptor signaling pathway were significantly higher in the cells treated with 3-SLP or 1-SALP/3-SALP CM compared with those treated with the vehicle CM. In the low affinity NGF receptor pathway, the expression levels of most components were higher in the 9-, 15- and 24-SALP CM-treated cells compared with the vehicle CM-treated cells. However, this level was significantly altered in cells treated with 3-SALP CM. Furthermore, an examination of the RLP function on calcium regulation revealed that only the LP- or RLP-treated cells exhibited changes in intracellular and extracellular calcium levels. RLP induced a significant decrease in the intracellular calcium levels and an increase in the extracellular calcium levels. These results suggest the possibility that steaming-processed LP may aid in the relief of neurodegenerative diseases through the NGF secretion ability and NGF signaling pathway.

In oriental medicine, Liriope platyphylla (LP) has long been regarded as a curative herb useful for the treatment of diabetes, asthma, and neurodegenerative disorders. The principal objective of this study was to assess the effects of steaming time and frequency for manufactured Red LP (RLP) on insulin secretion ability and insulin receptor signaling pathway. To achieve our goal, several types of LPs manufactured under different conditions were applied to INS cells and streptozotocin (STZ)-induced diabetic ICR mice, after which alterations in insulin concentrations were detected in the culture supernatants and sera. The optimal concentration for the investigation of insulin secretion ability was found to be 50 ug/mL of LP. At this concentration, maximum insulin secretion was observed in the INS cells treated with LP extract steamed for 3 h (3-SLP) with two repeated steps (3 h steaming and 24 h air-dried) carried out 9 times (9-SALP); no significant changes in viability were detected in any of the treated cells. Additionally, the expression and phosphorylation levels of most components in the insulin receptor signaling pathway were increased significantly in the majority of cells treated with steaming-processed LP as compared to the cells treated with LP prepared without steaming. With regard to glucose transporter (GLUT) expression, alterations of steaming time induced similar responses on the expression levels of GLUT-2 and GLUT-3. However, differences in steaming frequency were also shown to induce dose-dependent responses in the expression level of GLUT-2 only; no significant differences in GLUT-3 expression were detected under these conditions. Furthermore, these responses observed in vitro were similarly detected in STZ-induced diabetic mice. 24-SLP and 9-SALP treatment applied for 14 days induced the down-regulation of glucose concentration and upregulation of insulin concentration. Therefore, these results indicated that the steaming processed LP may contribute to the relief of diabetes symptoms and should be regarded as an excellent candidate for a diabetes treatment.

Pseudoaneurysm is a life-threatening complication of chronic or acute pancreatitis. This study was undertaken to evaluate the clinical features of pseudoaneurysm complicating pancreatitis.We reviewed the medical records of 7 patients diagnosed as pseudoaneurysms with chronic pancreatitis in Korea University Guro and Anam Hospital from January 1995 to March 2006 and analyzed their demographics, clinical courses and outcomes.All patients were men and mean age was 54.6 years (range, 43-67 years). All the cases occurred in the setting of chronic alcoholic pancreatitis complicated by pseudocyst. Abdominal pain was the unique initial clinical symptom in 5 cases, hematemesis in 1 case, and simultaneous abdominal pain with hematemesis in 1 case. Bleeding into pseudocyst developed in 5 cases, flowing into duodenum through pancreatic duct in 1 case and rupture into the descending colon in 1 case. Mean duration between onset of symptom and diagnosis of pseudoaneurysm was 7.8 days (range, 1-23 days). Six cases were diagnosed by abdominal computed tomography disclosing characteristic finding of focal high density area in the pseudocyst. Pulsed doppler abdominal sonography was performed before computed tomography in 3 cases and results were negative in 2 cases. Transcatheter arterial embolizations were initially performed in 6 cases, and there was no recurrent bleeding except one case of splenic infarction. Distal pancreatectomy was initially performed in 1 case.Pseudoaneurysms complicating chronic pancreatitis shows various clinical features. Transcatheter arterial embolization can be recommended as a primary therapeutic modality.

MELD-Na (model for end-stage liver disease with incorporation of serum sodium) was suggested to provide better survival prediction than MELD alone for patients with end stage liver disease. However, there is no data verifying the usefulness of MELD-Na for predicting short term mortality of cirrhotic patients in Korea. This study was aimed to determine whether MELD-Na would be more accurate in predicting short term mortality than other scoring systems such as Child-Turcotte-Pugh (CTP) or MELD.Data from 355 patients admitted due to liver cirrhosis were retrospectively reviewed. The cumulative survival rates were obtained. Prediction of mortality rate for three months and one year were analyzed using the area under the receiver's operating characteristics curve (AUC).One hundred patients (28%) died during the study period. All of the three systems showed significant differences in the cumulative survival rate according to the scores on admission (p0.001). The AUC of CTP, MELD, and MELD-Na in predicting three-months mortality were 0.828, 0.845, and 0.862 (p0.05), and the AUC of each score system for death within one year were 0.792, 0.800, and 0.831, respectively (p0.05). The AUC of MELD-Na in predicting short term death were the highest, although it was not statistically significant. Multivariate analysis showed that only MELD-Na was significantly related to three-month mortality (p=0.012).MELD-Na is more appropriate in predicting short term mortality, but larger scale studies are needed to confirm the superiority of MELD-Na to MELD and CTP in patients with liver cirrhosis.

A roller straightening process is a metal forming technique to improve the geometric quality of products such as straightness and flatness. The geometrical quality can be enhanced by eliminating unnecessary deformations produced during upstream manufacturing processes and minimizing any detrimental internal stress during the roller straightening process. The quality of steel cords can be achieved by the roller straightening depends the process parameters. Such process parameters are the roll intermesh, the roll pitch, the diameter of rolls, the number of rolls and the applied tension. This paper is concerned with the design optimization of the roller straightening process for steel cords with the aid of elasto‐plastic finite element analysis. Effects of the process parameters on the straightness of the steel cord are investigated by the finite element analysis. Based on the analysis results, the optimization of the roller straightening process is performed by the response surface method. The roller straightening process using optimum design parameters is carried out in order to confirm the quality of the final products.

Hepatorenal syndrome is a severe complication of cirrhosis, leading to death in more than 90% of cases in the absence of liver transplantation. Several treatments have been attempted as a bridge to liver transplantation. Among such treatments, terlipressin is a nonselective V1 vasopressin agonist. When comparing with ornipressin, it is known to have a similar vasoconstricting potency, but much less ischemic complication. We report a case of gangrene on toes and necrosis on the infusion site of left hand which developed after the use of terlipressin due to hepatorenal syndrome in a 41-year-old-man with liver cirrhosis. Ischemic complication of terlipressin is rare and there has been no case report in Korea. Although it is rare, we must pay attention to the peripheral ischemic complication of terlipressin.

Liriope platyphylla (LP) has long been regarded as a curative herb for the treatment of diabetes, asthma, and neurodegenerative disorders. To examine the therapeutic effects of Red LP (RLP) manufactured by steaming process on neurodegenerative disorders, significant alteration of the key factors influencing Alzheimer's Disease (AD) was detected in NSE/hAPPsw transgenic (Tg) mice after RLP treatment. The concentration of nerve growth factor (NGF) in serum increased in RLP-treated NSE/hAPPsw Tg mice compared with vehicle-treated Tg mice. However, downstream effectors of the NGF receptor signaling pathway, including TrkA and p75(NTR) proteins, were suppressed in RLP-treated NSE/hAPPsw Tg mice. Especially, Tg mice showed decreased levels of TrkA, p75(NTR), and RhoA expression. Production of Aβ-42 peptides was lower in RLP-treated NSE/hAPPsw Tg mice than in vehicle-treated Tg mice. Further, analysis of γ-secretase components showed that Aβ-42 peptide expression was downregulated. Of the four components, the expression of APH-1 and Nicastrin (NCT) decreased in RLP-treated NSE/hAPPsw Tg mice, whereas expression of PS-2 and Pen-2 was maintained or increased within the same group. Overall, these results suggest that RLP can help relieve neurodegenerative diseases, especially AD, through upregulation of NGF secretion ability, activation of NGF signaling pathway, downregulation of Aβ-42 peptide deposition, and alteration of γ-secretase components.

Equations for wave kinematics and wave dynamics based on small amplitude wave theory have been used in the prediction of wave deformations and wave-indused currents. However, the applicability of the linear wave theory is questionable in a river mouth where forced wave breaking and strong wave-current interaction take place. A numerical model based on the non-linear dispersive wave theory has been developed, the results by this model was compared with the values of the experiments and the linear theory. Wave transformations including shoaling, wave-current interaction and wave breaking by the model showed a good agreement with the experimental result. In the prediction of wave-induced currents, the excess momentum flux (Pxx) computed by the model has more reasonable value than the radiation stress ( Sxx) calculated by the small amplitude wave theory.