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A zeolite membrane and polymer membranes were prepared for the enrichment of NF3 waste gas. NF3 is a strong greenhouse gas with a 100 year global warming potential (GWP) of >16,600, and is mostly used in the plasma enhanced chemical vapor deposition (PECVD) process as an etching and cleaning gas. First, dense polymer films using polysulfone, polyimide, AF-1600®, AF-2400®, PDMS (polymethylsiloxane), PTMSP (poly (1-trimethylsilyl-1-propyne)), and PTMSDPA (poly[1-phenyl-2-[p-(trimethylsilyl)phenyl]acetylene]) were prepared, and their N2/NF3 separation performance was studied. High N2/NF3 ideal selectivity was obtained from the polyimide and polysulfone films, but these modules were not attractive for the NF3 enrichment process because of their low N2/NF3 mixture gas selectivity. SAPO-34 membranes were then prepared and applied for the NF3 enrichment process. This membrane exhibited promising separation performance (>200 N2/NF3 selectivity, >6.7 × 10−8 N2 mol/m2/s/Pa) for the NF3 enrichment process. However, in order to deal with a high waste stream volume, it was necessary to greatly increase the membrane area. Potential zeolite membrane frameworks for NF3 enrichment have been proposed through membrane-based system design.

Summary Background Linezolid improves the treatment outcomes of multidrug-resistant tuberculosis substantially. We investigated whether use of linezolid instead of ethambutol increases the proportion of sputum culture conversion at 8 weeks of treatment in patients with pulmonary tuberculosis. Methods We did a phase 2, multicentre, randomised, open-label trial for patients with pulmonary tuberculosis at the three affiliated hospitals to Seoul National University and National Medical Center (Seoul–Seongnam, South Korea). Patients, aged 20–80 years, with a positive sputum for pulmonary tuberculosis, but without resistance to rifampicin, and current treatment administered for 7 days or fewer, were randomly assigned at a 1:1:1 ratio into three groups. The control group received ethambutol (2 months) with isoniazid, rifampicin, and pyrazinamide. The second group used linezolid (600 mg/day) for 2 weeks and the third group for 4 weeks instead of ethambutol for 2 months. We used a minimisation method to randomise, and stratified according to institution, cavitation on chest radiographs, and diabetes. The primary endpoint was the proportion of patients with negative culture conversion of sputum in liquid media after 8 weeks of treatment. The results of this trial were analysed primarily in the modified intention-to-treat population. The trial is registered with ClinicalTrials.gov, number NCT01994460. Findings Between Feb 19, 2014, and Jan 13, 2017, a total of 429 patients were enrolled and 428 were randomly assigned into either the control group (142 patients), the linezolid 2 weeks group (143 patients), or the linezolid 4 weeks group (143 patients). Among them, 401 were eligible for primary efficacy analyses. In the modified intention-to-treat analyses, negative cultures in liquid media at 8 weeks of treatment were observed in 103 (76·9%) of 134 control patients, 111 (82·2%) of 135 in the linezolid 2 weeks group, and 100 (75·8%) of 132 in the linezolid 4 weeks groups. The difference from the control group was 5.4% (95% CI −4·3 to 15·0, p=0·28) for the linezolid 2 weeks group and −1·1% (−11·3 to 9·1, p=0·83) for the linezolid 4 weeks group. Numbers of patients who experienced at least one adverse event were similar across the groups (86 [62·8%] of 137 in control, 79 [57·2%] of 138 in the linezolid 2 weeks group, and 75 [62·0%] of 121 in the linezolid 4 weeks group). Resistance to linezolid was not identified in any patient. Interpretation Higher rates of culture conversion at 8 weeks of treatment with short-term use of linezolid were not observed. However, safety analyses and the resistance profile suggested the potential role of linezolid in shortening of treatment for drug-susceptible tuberculosis. Funding Ministry of Health and Welfare, South Korea.

The thermally insulating, fire-retardant, smokeless and flexible polymer nanofiber is an incredibly important material for mankind. This polymer nanofiber is expected to breed technological innovations in applications such as thermally insulated clothing and building materials. Here, we propose an electrospinning process to fabricate silica aerogel-filled polymer nanofibers by modifying the typical sol–gel chemistry process for the synthesis of silica aerogel. Silica aerogel-filled polyvinylidene fluoride (PVdF) nanofiber webs, fabricated using the proposed process, were fire-retardant, smokeless and flexible; they also exhibited a low thermal conductivity of 0.028 W·m−1·K−1, which was 26.3% lower than that of pure PVdF nanofiber webs. To study the unique thermal characteristics of nanofibers theoretically, a micromechanics-based, two-scale multiphase model was proposed, with consideration of fiber structure including nano and micro pores. These developments make an important contribution to bringing silica aerogel products to everyday life.

Background Jefferson fractures, or burst fractures of the C1 vertebra, can be managed surgically or conservatively, depending on their stability. Methods We identified all patients who were treated for a C1 fracture at our institution between 1999 and 2016 for retrospective analysis. Patients with any other concurrent cervical fractures or nontraumatic etiology of fracture were excluded. Stability was defined as either lateral mass displacement ≥7 mm on computed tomography or presence of transverse atlantal ligament disruption on magnetic resonance imaging. We collected data on patients' demographic, clinical, and radiographic presentation and identified variables independently associated with instability at presentation and failure to achieve fusion at follow-up. Results We identified 65 patients. On multivariable regression, instability at presentation was independently associated with atlantodens interval (odds ratio [OR] 2.357, 95% confidence interval [CI] [0.0629–1.271], P = 0.099) and type 3 fracture (OR 6.081, 95% CI [1.068–34.612], P = 0.042). Failure to achieve fusion was independently associated with age (OR 1.226, 95% CI [1.007–1.495], P = 0.043), motor vehicle collision as mechanism of injury (OR 22834.3, 95% CI [3.135–1.66e8], P = 0.027), and type 2 fracture (OR 168.537, 95% CI [1.743–16292.92], P = 0.028). Type 3 fracture was positively associated with halo vest for management (OR 17.171, 95% CI [2.882–102.289], P = 0.002) and negatively associated with a rigid cervical collar for management (OR 0.0616, 95% CI [0.0104–0.3653], P = 0.002). All 4 patients who underwent surgery presented with unstable fracture (P = 0.0187). Conclusions Atlantodens interval, mechanism of injury, and fracture type affect Jefferson fracture management decisions and outcomes, including instability at presentation and fusion at follow-up. Most fractures were managed nonsurgically regardless of stability.

Traditionally, external hazards are considered in the design of a building through the various combinations of loads prescribed in relevant design codes and standards. It is often the case that the design is governed by a single dominant hazard at a given geographic location. This is particularly true for earthquake and wind hazards, both of which impart time-dependent dynamic loads on the structure. Engineers may nevertheless wonder if a building designed for one of the two dominant hazards will satisfactorily withstand the other. Prior studies have indicated that in some cases, when a building is designed for a single dominant hazard, it does not necessarily provide satisfactory performance against the other hazard. In this paper, we propose a novel framework that builds upon performance-based design requirements and determines whether the design of a building is governed primarily by a single hazard or multiple hazards. It integrates site-dependent hazard characteristics with the performance criteria for a given building type and building geometry. The framework is consistent with the burgeoning area of probabilistic risk assessment, and yet can easily be extended to traditional, deterministically characterized design requirements as illustrated herein.

The strain generated by photoresponsive polymer actuators under external applied loads is a key performance parameter. Herein, we investigated the photogenerated strain under uniaxial loads in densely crosslinked azobenzene-incorporated liquid crystalline polymer (azo-LCP) actuators. Spectral analysis indicated that the liquid crystalline (LC) moieties and incorporated azobenzene moieties behave independently under load. The degree of LC mesogen distortions decreased as the applied load increased, whereas azobenzene isomerization showed high tolerance towards the external load. Such stress-response differences led to universal “two-stage” photogenerated strain behavior, with rapid decreases under low applied loads and steady linear decreases under relatively high loads. More importantly, we found that light intensity has little influence on important parameters such as the loading stage and actuator failure stress. However, these properties could be optimized by changing the crosslinking density (either azobenzene or side-chain LC concentration) in the polymeric network.

Steam generator is one of the major components in a nuclear power plant, and it consists of thousands of thin-walled tubes. The operating record of the steam generators has indicated that a number of axial cracks due to stress corrosion have been frequently detected in the tubes. Since the tubes are closely related to the safety and also the efficiency of a nuclear power plant, an establishment of the appropriate repair criterion for the defected tubes and its applications are necessary. The objective of this paper is to develop an accurate repair criterion for the tubes with axial cracks. To do this, a thorough review is performed on the key parameters affecting the tube integrity, and then the probabilistic integrity assessment is carried out by considering the various uncertainties. In addition, the sizes of critical crack are determined by comparing the burst pressure of the cracked tube with the required performance criterion. Based on this result, the new repair criterion for the axially cracked tubes is defined from the reasonably conservative value such that the required performance criterion in terms of the burst pressure is able to be met during the next operating period.

We found that the thermal conductivity of the polycarbonate (PC) composite filled with both 9.9 wt% expanded graphite (EG) and 0.1 wt% multi-walled carbon nanotube (MWCNT) fillers was synergistically improved by 49% compared to that of the PC composite filled with 10 wt% EG alone. In order to induce the optimal internal structure favorable for thermal conduction by enhancing the dispersion of the second MWCNT fillers, we applied a two-step melt-compounding to fabricate composites using a MWCNT masterbatch based on a polymerizable oligomer resin, cyclic butylene terephthalate (CBT), which is characterized by ultra-low viscosity and excellent impregnability during initial melting. Three-dimensional (3D) non-destructive characterization using X-ray micro computed tomography (micro-CT) was utilized to demonstrate the synergistic enhancement and to verify dispersion and 3D thermal network of the fillers in the composites accurately. The synergistic enhancement was significantly affected by the formation of the efficient thermally conductive pathways and dispersion of the second MWCNT fillers.

The blisters formation and destruction induced by the deuterium ions on a polycrystalline tungsten were investigated with varying irradiation deuterium ion fluence from 3.04 × 1023 to 1.84 × 1025 D m−2 s−1 and an fixed irradiated ion energy of 100 eV in an electron cyclotron resonance plasma source, which was similar to the far-scrape off layer region in the nuclear fusion reactors. Target temperature was monitored during the irradiation. Most of blisters formed easily on the grain with (1 1 1) plane orientation which had about 250 nm in diameter. In addition, the areal number density of blisters increased with increasing the ion fluence under the surface temperature reaching to about 900 K. When the fluence exceeded 4.6 × 1024 D m−2, the areal number density of the blister decreased. It could be explained that the destruction of the blister was initiated by erosion at the boundary region where the thickness of blister lid was thin and the sputtering yield was high by oblique incident ions, resulting in remaining the lid open, e.g., un-eroded center dome. It is possible to work as a tungsten dust formation from the plasma facing divertor material at far-SOL region of fusion reactor.

The size of expanded graphite (EG) was controlled using a high-speed crusher because a hybrid of differently sized fillers can induce a synergistic enhancement of the thermal conductivity in polymer composites. We found that the thermal conductivity of a polymer composite filled with both 10 wt% EG and 10 wt% high-speed crusher treated EG (wEG) was synergistically improved by 12.0 and 20.7% compared to that of polymer composites filled with 20 wt% EG and 20 wt% wEG alone, respectively. A three-dimensional (3D) non-destructive analysis using X-ray micro-computed tomography (micro-CT) was applied to explain the synergistic enhancement and to identify the dispersion and 3D network of EG fillers in the composites accurately. According to the non-destructive analysis results, the synergistic enhancement was caused by the formation of efficient thermally conductive pathways due to the hybrid of the differently sized EG and wEG fillers.

We found that the thermal conductivity of polymer composites was synergistically improved by the simultaneous incorporation of graphene nanoplatelet (GNP) and multi-walled carbon nanotube (MWCNT) fillers into the polycarbonate matrix. The bulk thermal conductivity of composites with 20 wt% GNP filler was found to reach a maximum value of 1.13 W/m K and this thermal conductivity was synergistically enhanced to reach a maximum value of 1.39 W/m K as the relative proportion of MWCNT content was increased but the relative proportion of GNP content was decreased. The synergistic effect was theoretically estimated based on a modified micromechanics model where the different shapes of the nanofillers in the composite system could be taken into account. The waviness of the incorporated GNP and MWCNT fillers was found to be one of the most important physical factors determining the thermal conductivity of the composites and must be taken into consideration in theoretical calculations.

The ITER project is aimed at demonstrating the feasibility of fusion as one of the possible energy options. A layout optimization is one of the design concerns for maintaining safety and reliability of the piping, because some piping penetrating the buildings is subjected to large seismic displacements. The objective of this study is to determine an optimum layout for the radioactive liquid transfer piping to withstand a given seismic displacements combined with internal pressure and thermal expansion. To do this, a series of finite element analyses were performed for various layouts. In addition, the feasibility for utilizing the double-walled structure was investigated. Analysis result shows that effects of the internal pressure and thermal expansion on the total stress are very small compared to that of the seismic displacements. Also, the stress as well as the deformation of the double-walled piping is larger than that of the single-walled piping although the difference is not big. Based on this result, an optimum configuration, a spiral along with U shape, is suggested.

The anisotropic development of thermal conductivity in polymer composites was evaluated by measuring the isotropic, in-plane and through-plane thermal conductivities of composites containing length-adjusted short and long multi-walled CNTs (MWCNTs). The thermal conductivities of the composites were relatively low irrespective of the MWCNT length due to their high contact resistance and high interfacial resistance to polymer resins, considering the high thermal conductivity of MWCNTs. The isotropic and in-plane thermal conductivities of long-MWCNT-based composites were higher than those of short-MWCNT-based ones and the trend can accurately be calculated using the modified Mori-Tanaka theory. The in-plane thermal conductivity of composites with 2 wt% long MWCNTs was increased to 1.27 W/m·K. The length of MWCNTs in polymer composites is an important physical factor in determining the anisotropic thermal conductivity and must be considered for theoretical simulations. The thermal conductivity of MWCNT polymer composites can be effectively controlled in the processing direction by adjusting the length of the MWCNT filler.

Morphological changes of graphite plasma facing component (PFC) were investigated with various ion irradiation conditions which may change the sputtering yield and the scrape-off layer (SOL) plasma property. The experiments were carried out by using electron cyclotron resonance deuterium plasma with the conditions of electron density range of 2.5–3.5 × 10 11 cm −3 , electron temperature range of 3.3–4.1 eV, and ion energy range of 17–100 eV. The graphite morphology was changed from plane to conical tip with increasing ion energy and dose. In addition, morphological changes increase the sputtering yield due to the increase of local angle of ion incidence. The inflow of hydrocarbon causes the increase of electron density and the decrease of electron temperature due to its higher dissociation and ionization rates than those of deuterium. This result suggests that the morphological changes of graphite should be considered in the SOL plasma interaction with graphite PFC.

To investigate an interaction between one-dimensional nanostructures and UV light, we prepared one-dimensional TiO 2 nanowires (TiO 2 -NWs) and nanotubes (TiO 2 -NTs) as a high-efficiency UV protector. The TiO 2 -NWs with rutile phase showed ∼8.6 nm of diameter and ∼127.6 nm of length. The TiO 2 -NTs with anatase phase exhibited ∼6.5 nm diameter and ∼100 nm length. The specific surface areas of the TiO 2 -NWs and TiO 2 -NTs are ∼34.0 and ∼464.8 m 2 g −1 , respectively. In particular, the TiO 2 -NTs exhibited fairly uniform pore size of ∼5.3 nm. The optical characteristics such as UV-scattering and absorbing were compared by UV–vis spectrometry in the range of UVB and UVA. The TiO 2 -NWs and TiO 2 -NTs exhibited much improved absorbance in UVB and UVA region as compared to commercial TiO 2 . Furthermore, the TiO 2 -NTs exhibited much increased reflectance in UVA region.

Objective Our objective was to evaluate whether the enhancement pattern, measured by changes in the signal- (SNRs) and contrast-to-noise ratios (CNRs), of hepatocellular carcinomas (HCCs) on gadoxetic acid-enhanced MRI reflects tumor differentiation. Subjects and methods Two hundred eighty-five patients with 286 surgically-confirmed HCCs who underwent gadoxetic acid-enhanced MRI were included (11 grade I, 267 grade II, 7 grade III, and 1 grade IV tumor). Unenhanced and dynamic images with a T1-weighted 3D turbo-field-echo sequence were obtained. Relative signal intensities of the tumors with respect to surrounding liver were evaluated and the SNRs and CNRs were calculated. Results SNR measurements demonstrated a fluctuating pattern (an increase in the SNR, followed by a decrease and a subsequent increase [or a decrease in the SNR followed by an increase and a subsequent decrease]) in 282 of 286 (98.6%) tumors. The SNR measurements also showed a single-peak SNR in the arterial phase (1.0% [3/286]) and 3 min delayed images (0.3% [1/286]) followed by a decrease in 4 (1.4% [4/286]) grade II tumors. Nearly all tumors (88.1% [252/286]), 9 (81.8% [9/11]) grade I, 236 (88.4% [236/267]) grade II, 6 (85.7% [6/7]) grade III, and 1 (100% [1/1]) grade IV tumor showed maximum absolute CNRs with negative values, which were most commonly found in 20 min delayed images (67.5% [170/252]). The remaining 34 of 286 (11.9%) tumors showed maximum absolute CNRs with positive values. Conclusion Regardless of the tumor grades, the most common manifestation was a SNR with a fluctuating pattern with time and maximum absolute CNRs with negative values, which were most commonly noted in the hepatobiliary phase.

In this study, a multi-objective optimal fuzzy control system for the response reduction of a wind-excited tall building has been proposed. A semi-active tuned mass damper (STMD) is used for vibration control of a 76-story benchmark building subjected to wind load. An STMD consists of a 100 kN magnetorheological (MR) damper and its natural period is tuned to the first-mode natural period of vibration of the example building structure. The damping force of the MR damper is controlled by a fuzzy logic controller. A multi-objective genetic algorithm is used for optimization of the fuzzy logic controller. Both the 75th floor acceleration response of the structure and the stroke of the STMD have been used as the objective functions for this multi-objective optimization problem. Because a multi-objective optimization approach provides a set of Pareto-optimal solutions, an engineer is able to select an appropriate design for the specific performance requirement. For a comparative study, a sky–ground hook control algorithm is employed for control of the STMD. Based on numerical results, it has been shown that the proposed control system can effectively reduce the STMD motion as well as building responses compared to the comparative sky–ground hook control algorithm. In addition, the control performance of the STMD controlled by the optimal fuzzy controller is superior to that of the passive TMD and is comparable to an active TMD, but with a significant reduction in power consumption.

We report shape-controlled Pd nanoparticles (G-Pd NPs) synthesized by means of polyol process using glycerol as a reducing agent with poly(vinyl pyrrolidone) as a capping agent in aqueous solution. The G-Pd NPs consist of triangular and hexagonal plates and decahedron with dominant {111} facets confirmed by X-ray diffraction analysis and field-emission transmission electron microscopy. In cyclic voltammograms, the G-Pd NPs exhibit such an improved formic acid electrooxidation due to the metallic nanophases with the dominant {111} facets without any serious agglomeration in comparison with commercial Pd/C.

The pure TiO2 and Ru-doped TiO2 nanoparticles obtained by means of hydrothermal process show one-dimensional nanowire (NW) structures with complete rutile phase confirmed by transmission electron microscopy and X-ray diffraction analysis. Using cyclic voltammetry in sulfuric acid solution, compared to the PtRu/TiO2-NW, the PtRu/Ru0.1Ti0.9O2-NW exhibits much higher current densities and thicker double layer region caused by an enhanced electrical conductivity of the NW and electrochemical properties of ruthenium element, respectively. For methanol electrooxidation, furthermore, the excellent catalytic activity and stability of the PtRu/Ru0.1Ti0.9O2-NW, as compared to that of the PtRu/TiO2-NW, may be due to improved electrical and electrochemical properties of the Ru0.1Ti0.9O2-NW support.

The cause of pancreatitis is unknown in as many as 30% of cases of recurrent acute pancreatitis, even after ERCP.To investigate the role of intraductal US (IDUS) for managing idiopathic recurrent pancreatitis (IRP).Prospective study.Tertiary referral hospital.Thirty-one patients with suspicious IRP with negative findings on ERCP.IDUS during ERCP.IDUS findings showing any possible cause of pancreatitis.IDUS revealed small bile duct stones (≤3 mm) in 5 patients (16.1%) and sludge in 3 patients (9.7%). The detection rate for a bile duct stone and sludge was significantly higher in patients with a dilated CBD than a nondilated CBD on ERCP (71.4 vs 12.5%; P.05). Recurrent pancreatitis did not develop in 7 of 8 patients with biliary stones or sludge after an endoscopic sphincterotomy (EST). Two patients (6.5%) demonstrated a small polypoid lesion on the distal end of the pancreatic duct. One patient underwent surgery for intra-ampullary cancer, and another one underwent EST without another attack of pancreatitis. Three patients (9.7%) showed evidence of chronic pancreatitis with small pancreatic stones and/or calcifications on IDUS.Small number of patients. IDUS results were not compared with those of conventional EUS. There was no reference standard for chronic pancreatitis as diagnosed by IDUS.IDUS identified a possible cause of idiopathic recurrent pancreatitis in 42% of patients with negative findings on ERCP. The IDUS-guided approach combined with ERCP and EST may be useful for decreasing recurring attacks of pancreatitis.

Atomic oxygen (AO) generation is experimentally and numerically investigated for in-situ plasma and post-plasma produced by dielectric barrier discharges (DBDs) for surface treatment. The AO generation in in-situ plasma inside a DBD reactor is closely related to the plasma characteristics depending on the applied voltage and O2 additive concentration, while the AO density distribution along the post-plasma ejected outside the reactor exit is influenced by the AO generation in the in-situ plasma, gas flow rate, and effluent distance. Contact angle measurements show that the metal surface characteristics, which are treated by in-situ plasma and post-plasma, respectively, are distinctive from each other depending on the AO densities.

The surface oxidation of metal is investigated through plasma treatments with an atmospheric-pressure dielectric barrier discharge (DBD) for comparison with a conventional thermal oxidation process. After the plasma treatment of a copper plate, the Cu surface was noted to have abundant CuO and Cu(OH)2 which act the part of hydrophilic functional elements. Highly improved wettability was also noted. When a greater amount of atomic oxygen is generated in the plasma by the DBD at a high applied voltage and a high O2 additive concentration, the hydrophilic functional elements become more abundant and therefore enhance the wettability of the oxidized surface.

We report polygonal Pd catalysts on carbon black synthesized by means of polyol process in the presence of poly(vinyl pyrrolidone) and NO 3 − ion. We find that the polygonal Pd/C has dominant {1 1 1} facets observed by X-ray diffraction method and transmission electron microscopy analysis. The current density for formic acid electrooxidation of polygonal Pd/C (1.908 mA cm −2 ) with controlled surface structures such as dominant {1 1 1} facets is much higher than Pd/C (0.478 mA cm −2 ) at 0 V. Furthermore, the polygonal Pd/C with controlled surface structures shows much improved performances in dye-sensitized solar cells (DSSCs) due to its highly thermal stability and enhanced catalytic activity for iodide reduction.

Integrated fixed film activated sludge (IFAS) is an increasingly popular modification of conventional activated sludge, consisting of the addition of solid media to bioreactors to create hybrid attached/suspended growth systems. While the benefits of this technology for improvement of nitrification and other functions are well-demonstrated, little is known about its effects on biomass settleability. These effects were evaluated in parallel, independent wastewater treatment trains, with and without IFAS media, both at the pilot (at two solids residence times) and full scales. While all samples demonstrated good settleability, the Control (non-IFAS) systems consistently demonstrated small but significant (p0.05) improvements in settleability relative to the IFAS trains. Differences in biomass densities were identified as likely contributing factors, with Control suspended phase densityIFAS suspended phase densityIFAS attached phase (biofilm) density. Polyphosphate content (as non-soluble phosphorus) was well-correlated with density. This suggested that the attached phases had relatively low densities because of their lack of anaerobic/aerobic cycling and consequent low content of polyphosphate-accumulating organisms, and that differences in enhanced biological phosphorus removal performance between the IFAS and non-IFAS systems were likely related to the observed differences in density and settleability for the suspended phases. Decreases in solids retention times from 8 to 4 days resulted in improved settleability and increased density in all suspended phases, which was related to increased phosphorus content in the biomass, while no significant changes in density and phosphorus content were observed in attached phases.

In this study the integrated system for progressive collapse analysis, which can evaluate the damage level of every member and automatically construct the modified structural model for the next analysis step, has been developed. The existing nonlinear analysis program code OpenSees was used as a finite element solver in the integrated system for progressive collapse analysis. The developed integrated system includes a pre-processor with intuitive graphic user interfaces and a post-processor that can simulate the progressive collapse by 3D graphic animation. Using the developed integrated system, example structures subjected to a column failure were analyzed, and the behavior of the structures was investigated in the context of how to model the failed members and whether the dynamic effects are considered or not. The analysis results show that the dynamic amplification can be larger than two which is recommended by the GSA and DoD guidelines and the collapse mechanism depends greatly on the modeling technique for failed members.

The steam generator in a nuclear power plant is a large heat exchanger that uses heat from a reactor to generate steam to drive the turbine generator. Rupture of a steam generator tube can result in release of fission products to environment outside. Therefore, an accurate integrity assessment of the steam generator tubes with cracks is of great importance for maintaining the safety of a nuclear power plant. The steam generator tubes are supported at regular intervals by tube support plates and rotations of the tubes are restrained. Although it has been reported that the limit load for a circumferential crack is significantly affected by boundary condition of the tube, existing limit load solutions do not consider the restraining effect of tube support plate correctly. In addition, there are no limit load solutions for circumferential cracks in U-bend region with the effect of tube support plate. This paper provides detailed limit load solutions for circumferential cracks in top of tube sheet and the U-bend regions of the steam generator tube with the actual boundary conditions to simulate the restraining effect of the tube support plate. Such solutions are developed based on three-dimensional (3-D) finite element analyses. The resulting limit load solutions are given in a polynomial form, and thus can be simply used in practical integrity assessment of the steam generator tubes.

The effectiveness of a supervisory fuzzy control technique for reduction of seismic response of a smart base isolation system is investigated in this study. To this end, a first generation, base isolated, benchmark building is employed for numerical simulation. The benchmark structure under consideration has eight stories and an irregular plan. Furthermore it is equipped with low damping elastomeric bearings and magnetorheological (MR) dampers for seismic protection. The proposed control technique employs a hierarchical structure of fuzzy logic controllers (FLC) consisting of two lower-level controllers (sub-FLC) and a higher-level supervisory controller. One sub-FLC has been optimized for near-fault earthquakes and the other sub-FLC is well-suited for far-fault earthquakes. These sub-FLCs are optimized by use of a multi-objective genetic algorithm. Four objectives, i.e. reduction of peak superstructure acceleration, peak isolation system deformation, RMS superstructure acceleration and RMS isolation system deformation are used in a multi-objective optimization process. When an earthquake is applied to the benchmark building, each of the sub-FLCs provides different command voltages for the semi-active controllers and the supervisory fuzzy controller appropriately combines the two command voltages based on a fuzzy inference system in real time. Results from numerical simulations demonstrate that isolation system deformation as well as superstructure responses can be effectively reduced using the proposed supervisory fuzzy control technique in comparison with a sample clipped optimal controller.

Toxic organic contaminants frequently serve as growth substrates for bacteria. However, long-term exposure to the organic contaminants can result in significant stress or "injury" to bacterial cells such that bacteria may lose, either temporarily or permanently, their capacity to degrade a specific toxic organic contaminant. In order to understand the relationship between biodegradability and physiological conditions of bacteria after a prolonged exposure to a contaminant, biomass samples collected from a sand column experiment, with toluene as the carbon source, were analyzed for bacterial physiology and spatial population distribution in the porous media. The column was seeded with three bacterial isolates that perform aerobic (Pseudomonas putida F1), denitrifying (Thauera aromatica T1), and facultative (Ralstonia pickettii PKO1) degradation of toluene were analyzed. Total, viable but not culturable with toluene, and toluene-culturable cells were enumerated using 4'6-diamidino-2-phenylindole (DAPI) staining and plate counting methods. Comparison of three types of cell counts showed that toluene-culturable cells were less than 40% of the total cell numbers. However, viable colonies transferred to a toluene media after cultivation on rich media regained their ability to degrade toluene. This implies that the temporary loss of their toluene degradation capacity is either due to an intracellular accumulation of degradation by-products, which have to be consumed in order for the cells to degrade toluene, or it is possible that cells have shifted to degrade other substrates such as toluene degradation intermediates or organic materials resulting from cell turnover. Comparison of cell counts with toluene concentration showed no exponential increase in total and viable cell numbers, as reported for flat bed biofilm reactor experiments. The overall fraction of toluene-culturable cells was highest at the highest toluene concentration near the column inlet, which indicates that the observed temporary loss of toluene culturability was not solely caused by a direct toxic effect from the long-term exposure to toluene.

We investigated beam characteristics of the thermal-birefringence compensated symmetric resonator which consists of two Nd:YAG laser rods with rod-end curvatures. Numerical analyses show that the stability and the beam quality in high-power operation region can be improved when the rod-ends are made in the form of negative lenses. In addition, the thermal birefringence in the symmetric two-rod resonator is well compensated in the overall stable range when the two rods are located closely to each other.

Porous TiO2 films were prepared by the micro-arc oxidation (MAO) of Ti plates, and their CO sensing properties at low concentrations (5–100 ppm) were investigated as an application for an air quality control sensor. The obtained rutile films exhibited the maximum CO gas response at 350 °C, which is typical for semiconductor-type gas sensors, and the Ra/Rg was ∼1.6 for 10 ppm CO (Ra: resistance in air, Rg: resistance in a sample gas). The magnitude of the gas response increased almost linearly with increasing the CO concentration from 5 to 100 ppm. The CO sensing performance of the TiO2 sensor in the presence of humidity was investigated and compared with that of a SnO2 sensor.

Two types of H2Ti3O7 powders were prepared by ion exchange and hydrothermal methods, and the H2 sensing properties of the H2Ti3O7-derived TiO2 sensors were examined. In the ion exchange method, Na2Ti3O7 was first synthesized via a solid-state reaction, and H2Ti3O7 was obtained from Na+/H+ exchange on Na2Ti3O7. H2Ti3O7 was also prepared via a hydrothermal reaction of TiO2 powder in a NaOH solution. The morphology, size, and phase evolution of H2Ti3O7 were found to be strongly dependent on the preparation methods. The TiO2 sensors fabricated by the H2Ti3O7 powders calcined at 700 °C (ion exchanged) exhibited an excellent gas response (S = 30,000) to 1.0% H2/N2 at 500 °C, which was three orders of magnitude higher than that of the hydrothermally synthesized powder and commercial anatase powder even though its specific surface area was smaller. The higher H2 gas response in the TiO2 sensor derived from the ion exchanged H2Ti3O7 is discussed in terms of the metastable β-TiO2 and anatase phases.

We theoretically investigate the characteristics of an unsymmetric resonator with single Nd:YAG rod to find the best condition for getting the highly efficient intracavity second harmonics. The beam quality is analyzed with ABCD matrixes including the thermal characteristic of Nd:YAG rod. The analysis is focused on stability, M 2 , beam waist and mode-volume of laser beam inside resonator. The results show that the smallest beam waist and a large TEM 00 mode-volume can be achieved when a Nd:YAG rod closely contacts one of the laser mirrors. This means that the second harmonics of intracavity type generated under these conditions can be highly efficient.

Full-scale experiments are carried out on a single-degree-of-freedom mass that is equipped with a hybrid base isolation system. The isolator consists of a set of four friction pendulum system (FPS) bearings and a magnetorheological (MR) damper. The 13,620 kg mass and its hybrid isolation system are subjected to various intensities of near- and far-fault earthquakes on a large shake table. The proposed fuzzy controller uses feedback from displacement or acceleration transducers attached to the structure to modulate resistance of the semi-active damper to motion. Results from several types of passive and semi-active control strategies are summarized and compared. The study shows that a combination of FPS bearings and an adjustable MR damper can provide robust control of vibration for a large full-scale structure undergoing a wide variety of seismic loads. Low power consumption, real-time feedback control, and fail-safe operation are validated in this study. A combination of the FPS bearings and the MR damper appears to offer significant possibilities for reduction of displacement and acceleration due to seismic load. A neuro-fuzzy model is used to represent behavior of the damper for various displacement, velocity, and voltage combinations that are obtained from a series of laboratory evaluation tests. Modeling of the FPS bearings is carried out with a nonlinear analytical equation and neuro-fuzzy training. Numerical simulation using neuro-fuzzy models of the MR damper and FPS bearings predict the response of the hybrid base isolation system very well. Results show that dynamic behavior of the FPS bearings and MR damper can be successfully estimated using these neuro-fuzzy models.

Highly oriented polycrystalline TiO2 films were grown on sapphire substrates with various orientations using rf magnetron sputtering, and the effects of the crystallographic orientation on the H2 and CO gas sensing performance were investigated. The orientation of the TiO2 films was strongly dependent on the substrate orientation such that (1 0 1)/(1 0 0), (1 0 1), (0 0 1), and (1 0 0) oriented TiO2 films were formed on ( 1 1 2 ¯ 0 ) (a-cut), ( 1 1 ¯ 0 2 ) (r-cut), ( 1 0 1 ¯ 0 ) (m-cut), and (0 0 0 1) (c-cut) Al2O3, respectively. A fine surface feature developed in the films grown on ( 1 1 2 ¯ 0 ) and ( 1 0 1 ¯ 0 ) Al2O3 and a rather rough surface was obtained in case of the ( 1 1 ¯ 0 2 ) Al2O3 substrate. The deposited TiO2 films showed a short response time and high gas response toward H2 and CO balanced with N2. The TiO2 film grown on ( 1 1 2 ¯ 0 ) Al2O3 exhibited the highest H2 gas response possibly due to the (1 0 0) orientation and high surface area. The (0 0 1) orientation of TiO2 showed the highest selectivity toward H2 against CO.

Several recent works investigate the performance of smart base isolation systems and show that they can reduce base drifts without accompanying increases in acceleration that are seen with conventional passive isolation systems. To date, many viable smart base isolation systems have been proposed. In this study, a novel friction pendulum system (FPS) and an MR damper are employed as the isolator and supplemental damping device, respectively, of the smart base isolation system. A fuzzy logic controller (FLC) is used to modulate the MR damper because the FLC has an inherent robustness and ability to handle non-linearities and uncertainties. A genetic algorithm (GA) is used for optimization of the FLC. The main purpose of employing a GA is to determine appropriate fuzzy control rules as well to adjust parameters of the membership functions. To this end, a GA with a local improvement mechanism is applied. This method is efficient in improving local portions of chromosomes. Neuro-fuzzy models are used to represent dynamic behavior of the MR damper and FPS. The effectiveness of the proposed method for optimal design of the FLC is judged based on computed responses to several historical earthquakes. It has been shown that the proposed method can find optimal fuzzy rules and the GA-optimized FLC outperforms not only a passive control strategy but also a human-designed FLC and a conventional semi-active control algorithm.

The nickel/cobalt bilayer salicidation technology which enables an agglomeration-free silicidation even on narrow-line poly gate was investigated and described in detail. Si/Ni/Co and Si/Co/Ni bilayer stack were evaluated and the effect of thickness ratio between Ni and Co on phase transformation and on thermal stability was examined and the optimum thickness ratio was extracted electrically. For the first time, the Ni/Co bilayer salicidation process was adopted in sub-40nm poly gate and consequently, the good gate poly resistance and leakage characteristics were obtained. Therefore, Ni/Co bilayer can be regarded as a suitable solution for salicide process in sub-40nm high performance devices.

Nb-doped BiFeO3 polycrystalline ceramics were synthesized by a solid-state reaction and their dielectric and magnetic properties were investigated. Nb-doping increased the electrical resistivity of BiFeO3 by approximately six orders of magnitude, which allowed the dielectric properties to be determined at room temperature. The room temperature dielectric constant was ∼100 and the electric hyteresis loops were not really saturated in the Nb-doped BiFeO3 ceramics. Nb-doped BiFeO3 also showed a ferromagnetic-like behavior with Mr=0.015 emu/g and Hc=500 Oe, which is similar to the solid solution system of BiFeO3 and BaTiO3. The coupling between electric dipole and magnetic dipole was estimated by determining the changes of the dielectric constant with the external magnetic field up to 90 kOe.

A highly sensitive H 2 gas sensor was prepared by the thermal oxidation of a Ti plate at 600–1000 °C. The H 2 sensitivity (the ratio of the resistances between N 2 and 1.0% H 2 balanced with N 2 ) of the oxidized TiO 2 increased exponentially with increasing oxidation temperature up to 900 °C but decreased drastically at 1000 °C. The maximum sensitivity to 1.0% H 2 was 1.2 × 10 6 , which is the highest value reported in the literature. The mechanism for the enhanced H 2 sensing was examined by investigating the phase, thickness and morphology of the oxidized TiO 2 layer and the sensor response time. The thermally oxidized specimens exhibited an approximately linear dependence of the sensitivity on the H 2 concentrations from 50 to 10,000 ppm, and excellent sensitivity (∼10 3 ) was still obtained in the sensor operated at temperatures as low as 150 °C.

In many cases, high-rise building structures are designed as a framed structure with shear walls that can effectively resist horizontal forces. Many of the high-rise apartment buildings recently constructed in the Asian region employ the box system that consists only of reinforced concrete walls and slabs as the structural system. In most of these structures, a shear wall may have one or more openings for functional reasons. It is necessary to use a refined finite element model for an accurate analysis of a shear wall with openings. But it would take a significant amount of computational time and memory if the entire building structure were subdivided into a finer mesh. Thus an efficient method that can be used for the analysis of a high-rise building structure with shear walls regardless of the number, size and location of openings in the wall is proposed in this study. The proposed method uses super elements, substructures and fictitious beams. Static and dynamic analyses of example structures with various types of opening were performed to verify the efficiency and accuracy of the proposed method. It was confirmed that the proposed method can provide results with outstanding accuracy requiring significantly reduced computational time and memory.

Heterotropic bacteria can degrade organic substrates utilizing different terminal electron acceptors. The sequence of electron acceptor utilization depends on the energy yield of the individual reaction pathway, which decreases as the redox potential decreases. Due to these differences in energy yield, and an inhibiting activity of oxygen on some enzymatic processes, the simultaneous utilization of oxygen and nitrate as terminal electron acceptors may not occur for many degradation processes, unless the oxygen concentration falls below a given threshold level (about 0.2 mg/l). Two sand column experiments were conducted, with toluene as the carbon source, and showed an apparent simultaneous utilization of oxygen and nitrate as electron acceptors in regions where the oxygen concentration was significantly higher (⩾1.1 mg/l) than the above mentioned threshold concentration. Results from aerobic and anaerobic plate-count analyses showed growth of both aerobes and denitrifiers in the zone of the column where simultaneous utilization of oxygen and nitrate was observed. From these observations, it was postulated that the porous media contained oxygen-free microlocations where the denitrifiers were able to degrade the toluene. To simulate the observed dynamics, a dual biofilm model was implemented. This model formulation assumes that the biofilm is composed of two distinct layers, where the outer layer is colonized by aerobic bacteria and the inner layer by denitrifying bacteria. The thickness of the aerobic layer is such that oxygen is depleted at the boundary of these two layers, resulting in oxygen-free microlocations that allows denitrification to proceed, even though oxygen is still present in the bulk fluid phase. The model simulations compared well to the experimental profiles. Model analyses indicated that changes in physical, chemical, and hydrologic parameters could change the length and location of the zone where at the macroscopic level, oxygen and nitrate are utilized simultaneously. Comparisons of the proposed model to macroscopic modeling approaches showed that a dual biofilm model is able to describe the simultaneous utilization of oxygen and nitrate more accurately.

New alkali-soluble aromatic polyimides were prepared by a direct one-step polycondensation of 3,6-di(4-carboxyphenyl)pyromellitic dianhydride with common aromatic diamines in the presence of isoquinoline at 170 °C. The obtained polymers with inherent viscosities of the 0.62–1.01 g/dl range were all amorphous and highly soluble in dilute aqueous NaOH and tetramethylammonium hydroxide. Upon heating in TGA, the carboxylic acid groups degraded away at lower temperatures and the chain backbone did at higher temperatures. In DSC, no glass transition could be detected before decomposition. The alternating multilayer nano-films from the polyimides and poly(ethyleneimine) were prepared by the molecular self-assembly method and characterized by ellipsometry and X-ray reflectivity.

We propose and numerically investigate a method to remove a narrow unstable zone invaded in the stable region of a two-rod resonator with a thermal birefringence compensator. The method is based on the modification of the two thermal focal lengths of a laser rod for radial and tangential polarizations using an additional lens. This is done by installing the additional lens at the center of the plane-parallel symmetric resonator. We find that the wide stable region without the narrow unstable zone is achieved when the focal length of the additional lens is approximately equal to the half length of the resonator.

The box system that consists of reinforced concrete walls and slabs is adopted for many high-rise apartment buildings recently constructed. In an apartment building, shear walls may have one or more openings for functional reasons. Some researches on the analysis of shear wall with openings were performed, but some restrictions prevent those research results from being applied to the practical analysis and design procedure. It is necessary to use fine mesh finite element models for an accurate analysis of a box system structure with openings. But it would take a significant amount of computational time and memory if the entire building structure were subdivided into a finer mesh. An efficient analysis method that can be used regardless of the number, size and location of openings is proposed in this study. The analysis method uses super elements developed using the matrix condensation technique. Static and dynamic analyses of example structures having various types of openings were performed to verify the efficiency and accuracy of the proposed method. The analyses of example structures demonstrated that the proposed method can be used for the analysis of a shear wall structure with openings. Outstanding accuracy in analysis could be achieved with drastically reduced computational time and memory.

The dependence of structural properties and surface morphology of Cu–In alloy layers on the composition and sputtering deposition sequence were investigated by X-ray diffraction, scanning electron microscopy and energy-dispersive X-ray spectroscopy. The properties of the co-sputtered alloy layers changed abruptly around the composition boundary when the Cu/In ratio reached 1/2. This can be explained by the effective heat of formation (EHF) model, which has been used to predict the sequence of phase formation for metal diffusion couples. The use of a co-sputtered alloy layer with a high In concentration was not suitable for fabricating solar cells, because the film had a very rough morphology due to large In islands formed on the CuIn2 phase. However, it was possible to minimize this phase by In sputtering followed by co-sputtering with a Cu/In ratio of 1 (Cu–In/In/Glass). This permitted the fabrication of a homogeneous Cu–In alloy layer, which was not possible through the simple co-sputtering.

Box system structures, composed of only reinforced concrete walls and slabs, have been recently adopted for many high-rise apartment buildings. Commercial software such as ETABS, commonly used for the analysis of high-rise apartment buildings, assumes a rigid diaphragm for floor slabs. The flexural stiffness of slabs is generally ignored in the analysis. This assumption may be reasonable for the analysis of framed structures. In box system structures like apartment buildings, however, the floor slabs may have a significant influence on the lateral response of the structures. If the flexural stiffness of slabs in a box system structure is totally ignored, the lateral stiffness may be significantly underestimated. In reality, the cracked section property of a slab will determine the amount of its flexural stiffness that will be included in the analysis. In order to include the flexural stiffness of slabs, the slab needs to be modeled with plate elements. If the slab is subdivided into many plate elements while keeping each shear wall with a large element (as generally modeled with commercial software), the compatibility condition will not be satisfied at the interface of the slab and the shear wall. To enforce the compatibility condition at the interface, a fictitious beam is introduced. It would cost a significant amount of analysis time and computer memory to model the floor slab with many subdivided plate elements in every floor of a high-rise building. In this study, an efficient method is proposed to analyze high-rise box system structures considering the effects of floor slabs. The proposed method will reduce computational time and memory in the analysis by using the substructuring technique and matrix condensation.

We investigate the effect of distance between two rods of a double laser-head resonator on stability and beam quality. The characteristics are analyzed in terms of the beam propagation factor ( M 2 ) and TEM 00 mode volume. The results show that, in a thermal-birefringence compensation scheme, low M 2 value can be achieved when each rod is, respectively, placed near each laser mirror. And we find that the distance between two inner principal planes of two rods should be near the sum of the thermal focal lengths to compensate a thermal birefringence as well as to get high power without optical damage.

Background: There was limited data about the clinical and ECG characteristics for prediction of new-onset LV dysfunction in patients with frequent idiopathic VPCs >10% in the long-term follow up. Methods: The Kosin University 24-hours holter monitoring, echocardiography, ECG database were reviewed

Microwave-assisted hydrothermal reaction to prepare barium titanate (BaTiO3) particles using titanium acylate precursors was investigated. Experimental variables taken into account in this study were the reaction type (reflux and autoclave), the reaction time and the Ba to Ti ratio in sol solutions. Autoclave reactions were more effective than reflux reactions in terms of time and barium utilization efficiency. In both type reactions, the variation in Ba to Ti ratio in sol solutions led to substantial changes in particle morphology as well as Ba:Ti stoichiometry in resulting particles. Mechanisms for those changes were proposed. Characterization of synthesized particles were performed via SEM, XRD, Raman, XPS and elemental analysis based on ICP.

The threshold and reflectivity of the stimulated Brillouin scattering (SBS) were investigated in an excited laser gain medium. The SBS in a steady-state was modeled numerically and its results for the threshold and reflectivity were compared with experimental results of SBS in a Rhodamine 6G solution pumped by a frequency-doubled Nd:YAG laser. It is demonstrated that the reflectivity has the maximum value at a certain intensity of an incident laser beam.