Estimation of Appropriate Process Parameters for a Plasma Electron Beam Re-Melting Process Using Finite Element Analysis

Metal additive manufacturing using electron beam melting (EBM) process applies electron beam for heating, sintering, and melting of powders to fabricate a three-dimensional component. The component may contain residual porosity internally and may be subjected to poor surface finish externally. To improve the quality of the surface finish and densification, re-melting is conducted. The purpose of this paper was to estimate the appropriate process conditions for a plasma electron beam remelting process using heat transfer finite element analyses (FEAs). The impact of the travel speed of table and thickness of the deposited part on temperature distributions were examined. The size of molten pool was estimated from the results of the thermal FEA. From the estimated size of molten pool, the travel speed of table and the hatch spacing between remelting tracks are discussed and selected as the appropriate process conditions for electron beam re-melting process from the perspective of minimum overlapping region of the molten pool

Search Tree Generation for the Exception Handling of E-Commerce Delivery Process

A business process management system (BPMS) offers the facility to define new processes or update the existing processes. However, exceptional or non-routine tasks require the intervention of domain experts or generation of the situation specific resolution process. This paper assumes that sufficient amount of business process exception handling cases are stored in the process repository. Since the retrieval of the best exception handling process requires good understanding about the exceptional situation, context awareness is an important issue. To facilitate the representation of the exceptional situation and to enable the selection of the best exception handling process, we adopted the `situation variable' and `decision variable' construct. A case example for exception handling in the e-commerce delivery process is provided to illustrate how the proposed construct works. We applied the C5.0 algorithm to build the optimum search tree

GaAs droplet quantum dots with nanometer-thin capping layer for plasmonic applications

We report on the growth and optical characterisation of droplet GaAs quantum dots with extremely-thin (11 nm) capping layers. To achieve such result, an internal thermal heating step is introduced during the growth and its role in the morphological properties of the quantum dots obtained is investigated via scanning electron and atomic force microscopy. Photoluminescence measurements at cryogenic temperatures show optically stable, sharp and bright emission from single quantum dots, at near-infrared wavelengths. Given the quality of their optical properties and the proximity to the surface, such emitters are ideal candidates for the investigation of near field effects, like the coupling to plasmonic modes, in order to strongly control the directionality of the emission and/or the spontaneous emission rate, crucial parameters for quantum photonic applications.Comment: 1 pages, 3 figure

Role of core needle biopsy as a first-line diagnostic tool for thyroid nodules: a retrospective cohort study

Purpose The purpose of this study was to evaluate the diagnostic efficacy of fine-needle aspiration (FNA), core needle biopsy (CNB), and combined FNA/CNB for the first-line diagnosis of thyroid nodules. Methods A total of 782 consecutive nodules that underwent simultaneous FNA and CNB were analyzed in this study. We compared the rate of inconclusive results and the diagnostic values for malignancy among FNA, CNB, and combined FNA/CNB. Results CNB showed a lower rate (10.2%) of inconclusive results than FNA (23.7%) (P<0.001). Combined FNA/CNB showed a lower rate (6.5%) of inconclusive results than FNA (all nodules, P<0.001; macronodules, P<0.001; and micronodules, P<0.001, respectively) or CNB (all nodules, P<0.001; macronodules, P<0.001; and micronodules, P=0.003, respectively). Combined FNA/CNB and CNB showed significantly higher sensitivity, accuracy, and diagnostic performance for malignancy as defined by criterion 1 (Bethesda category VI) or criterion 2 (Bethesda categories IV/V/VI) than FNA (P<0.001). However, there was no significant difference in the sensitivity, accuracy, or diagnostic performance between combined FNA/CNB and CNB (with criterion 1, P=0.063, P=0.063, and P=0.412, respectively; with criterion 2, P=0.500, P=0.500, and P=0.348, respectively). Conclusion CNB was found to be more effective than FNA for the diagnosis of thyroid nodules, and its sensitivity and diagnostic performance for malignancy were similar to those of combined FNA/CNB. CNB has the potential to be an effective alternative first-line diagnostic tool for thyroid nodules when performed by an experienced operator

A New Hardware Correlator in Korea: Performance Evaluation using KVN observations

We report results of the performance evaluation of a new hardware correlator in Korea, the Daejeon correlator, developed by the Korea Astronomy and Space Science Institute (KASI) and the National Astronomical Observatory of Japan (NAOJ). We conducted Very Long Baseline Interferometry (VLBI) observations at 22~GHz with the Korean VLBI Network (KVN) in Korea and the VLBI Exploration of Radio Astrometry (VERA) in Japan, and correlated the aquired data with the Daejeon correlator. For evaluating the performance of the new hardware correlator, we compared the correlation outputs from the Daejeon correlator for KVN observations with those from a software correlator, the Distributed FX (DiFX). We investigated the correlated flux densities and brightness distributions of extragalactic compact radio sources. The comparison of the two correlator outputs show that they are consistent with each other within $<8\%$, which is comparable with the amplitude calibration uncertainties of KVN observations at 22~GHz. We also found that the 8\% difference in flux density is caused mainly by (a) the difference in the way of fringe phase tracking between the DiFX software correlator and the Daejeon hardware correlator, and (b) an unusual pattern (a double-layer pattern) of the amplitude correlation output from the Daejeon correlator. The visibility amplitude loss by the double-layer pattern is as small as 3\%. We conclude that the new hardware correlator produces reasonable correlation outputs for continuum observations, which are consistent with the outputs from the DiFX software correlator.Comment: 13 pagee, 9 figures, 3 tables, to appear in JKAS (received February 9, 2015; accepted March 16, 2015

Six-Month Comparison of Coronary Endothelial Dysfunction Associated With Sirolimus-Eluting Stent Versus Paclitaxel-Eluting Stent

ObjectivesThis study was designed to investigate whether endothelial dysfunction is related to drug-eluting stent (DES) implantation at 6 months after stenting.BackgroundCurrent available DES could delay vessel healing and subsequently impair endothelial function.MethodsEndothelial function was estimated at 6-month follow-up in 75 patients (31 men, mean age 62.1 years) with a DES (39 sirolimus-eluting stents [SES], 36 paclitaxel-eluting stents [PES]), and 10 patients with a bare-metal stent (BMS) to the left anterior descending artery, by incremental acetylcholine (Ach) infusion (20 μg/min, 50 μg/min, 100 μg/min) and nitrate (200 μg/min) into the left coronary ostium. Vascular responses were quantitatively measured in arterial segments 5 mm proximal and distal to DES and compared with corresponding segments in the BMS group and midsegments in the left circumflex artery as a reference nonstented artery. All antianginal agents were withheld for at least 72 h before coronary angiography.ResultsGreater vasoconstriction to Ach was observed in both the SES and PES groups than in the BMS group or control segments of left circumflex artery. Vasoconstriction to Ach was more prominent in arterial segments distal to stents in both SES and PES groups compared with those in the BMS group (p &lt; 0.001). The degree of vasoconstriction to Ach was similar between the SES and PES groups. Endothelium-independent vasodilatation to nitrate did not differ significantly between the study groups.ConclusionsAbnormal vasoconstriction to Ach was found in the SES and PES groups, especially in arterial segments distal to DES at 6 months after stenting, which suggests that DES has a potential long-term adverse effect on local coronary endothelial dysfunction

Bare-metal stents versus drug-eluting stents in large (≥3.5mm) single coronary artery: Angiographic and clinical outcomes at 6 months

SummaryBackgroundAlthough drug-eluting stents (DES) have been shown to dramatically reduce restenosis and improve the rate of event-free survival in large randomized trials, the benefit of DES appears to be limited to restenosis. In large arteries, it is not clear which type of stent is more superior in angiographic and clinical outcomes between DES and bare-metal stents (BMS). We compared the angiographic and clinical outcomes of DES versus BMS in large arteries (≥3.5mm).MethodTwo hundred and forty patients from March 2002 to March 2007 received stents; 196 patients were treated with DES (44.9% sirolimus-eluting stents; 43.9% paclitaxel-eluting stents; 11.2% zotarolimus-eluting stents) and 44 with cobalt–chromium BMS for single de novo lesions in a large vessel. All subjects received aspirin, clopidogrel, and/or cilostazol as the standard antiplatelet regimen. The angiographic and clinical outcomes were evaluated at 6 months.ResultsFor the baseline characteristics, there were no significant differences between the DES and BMS groups. In addition, for the initially implanted stent there was no difference in the length, stent diameter, and lesion site between the two groups. After 6 months, the follow-up angiogram showed that in-stent diameter restenosis and late loss was more common with BMS than DES (39±21% vs. 19±17%, p=0.007; 1.44±0.83mm vs. 0.62±0.58mm, p=0.009, respectively). However, the target-lesion revascularization/target-vessel revascularization, and total major adverse cardiac events showed no significant differences between the groups (5.3% vs. 3.6%, p=0.62; 5.3% vs. 4.6%, p=0.86, respectively).ConclusionThe DES and cobalt–chromium BMS placed in large coronary arteries showed equally favorable 6-month clinical outcomes, although the 6-month angiographic results appeared more favorable in the DES group than in the BMS group