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Several NiO/TiO2 composites fabricated by the impregnation method were employed as photocatalysts for the photoreduction of gaseous CO2 in this study. The characterizations of fabricated photocatalysts were observed by XRD, FE-SEM, EDS, N2 adsorption-desorption, and UV–vis spectroscopy. The distribution of Ni, Ti, and O atoms on the surface of these photocatalysts was demonstrated to be uniform, and the BET surface areas were varied slightly with the increase of NiO loading. Meanwhile, the absorption edge of fabricated photocatalysts was found to shift towards the visible region and the bandgap energy was decreased. The photocatalytic reaction was conducted in a continuous-flow reactor under UV irradiation. Methane was identified to be the main product and produced in the order: 10 wt% NiO/TiO2 > TiO2 > 20 wt% NiO/TiO2. The maximum methane yield reached at 4.69 mmol/gcatalyst over 10 wt% NiO/TiO2 and was twice higher than that of P-25. The formation of p-n junction significantly improved the photocatalytic activity of P-25. Furthermore, the proposed schematic diagram for photocatalytic CO2 reduction in the gaseous phase under NiO-TiO2 / UV process was introduced.

Chemical looping with oxygen uncoupling (CLOU) is an innovative alternative to conventional combustion. CuO/ZrO2 oxygen carriers were tested in this system for their effectiveness and resilience. Cupric oxide (CuO) was demonstrated to be a reliable oxygen carrier for oxygen-uncoupling with consistent recyclability even after 50 redox cycles in a thermogravimetric analyzer (TGA). The reduction of CuO to generate Cu2O and oxygen was observed to be improved markedly for experiments operated at higher temperatures; however, the oxidation of Cu2O by air to generate CuO was hindered for experiments carried out at elevated temperatures. The reduction rate of fabricated CuO/ZrO2 particles containing 40% CuO was enhanced with increasing temperature and decreased with increasing particle size for experiments operated in a fixed bed reactor. The geometrical contraction and Avrami-Erofe’ev models were demonstrated to be appropriate for describing the reduction and oxidation of CuO/ZrO2, respectively. The activation energies for the reduction and oxidation were determined to be 250.6 kJ/mol and 57.6 kJ/mol, respectively, based on experimental results in the temperature range between 850 and 1000 °C.

In order to verify the performance and safety of the solid-type breeding blanket concept, the thermal conductivity of the pebble bed is required as an essential parameter for design and analysis of the blanket. The hot wire, hot disk, guarded hot plate, and laser flash method are considered as measurement technique for the thermal conductivity of pebble bed. This study aims at the provision of the thermal conductivity of Li2TiO3 pebble bed, which is one of the candidates for tritium breeder material in the solid-type breeding blanket. The laser flash method was adopted due to its advantages compared with other methods, such as high accuracy and repeatability, easy sample preparation, absolute measurement technique, and so on. In this method, the thermal diffusivity is directly measured by the laser flash system, and then the thermal conductivity is obtained by multiplying density and specific heat to the measured thermal diffusivity. The thermal conductivity of the Li2TiO3 pebble bed with packing factor of 57% increased with increasing temperature up to 500 °C and was saturated to 1.3 W/m/K at more than 500 °C.

Dye-sensitized solar cells (DSSCs) are constructed on top of transparent conducting oxide (TCO) substrates that permit incident light to enter the cells and facilitate charge transport from back contact to the external circuit. The most common TCO substrate used in DSSCs, as well as other optoelectronic devices, is an F-doped tin oxide (FTO). Another tin oxide-based TCO is Indium tin oxide (ITO), which is also used in optoelectronic devices. However, zinc oxide-based TCOs –aluminum-doped zinc oxide (AZO) and gallium-doped zinc oxide (GZO) – were not used that much, especially in DSSCs. In the present work, we examined the suitability of four transparent conducting oxides – FTO, ITO, AZO, and GZO – for the application in DSSCs as substrate. We employed all four TCOs to fabricate platinized counter electrode (CE) for DSSCs in three different methods: thermal reduction of Pt precursor at 380 °C, chemical reduction of Pt precursor at 70 °C, and RF-sputtering Pt at room temperature. The cation-doped zinc oxide-based TCOs are not thermally and chemically stable. However, FTO, being anionic-doped tin oxide-based TCO, is the most thermally and chemically stable among the four TCOs studied in this work.

Purpose In this study, we aimed to evaluate the clinical validity of the modified tunneling technique using minimal soft tissue harvesting and volume-stable collagen matrix in the anterior mandible. Methods In total, 27 anterior mandibular teeth and palatal donor sites in 17 patients with ≥1 mm of gingival recession (GR) were analyzed before and after root coverage. For the recipient sites, vertical vestibular incisions were made in the interdental area and a subperiosteal tunnel was created with an elevator. After both sides of the marginal gingiva were tied to one another, a prepared connective tissue graft and volume-stable collagen matrix were inserted through the vestibular vertical incision and were fixed with resorbable suture material. The root coverage results of the recipient site were measured at baseline (T0), 3 weeks (T3), 12 weeks (T12), and the latest visit (Tl). For palatal donor sites, a free gingival graft from a pre-decided area avoiding the main trunk of the greater palatine artery was harvested using a prefabricated surgical template at a depth of 2 mm after de-epithelization using a rotating bur. In each patient, the clinical and volumetric changes at the donor sites between T0 and T3 were measured. Results During an average follow-up of 14.5 months, teeth with denuded root lengths of 1–3 mm (n=12), 3–6 mm (n=11), and >6 mm (n=2) achieved root coverage of 97.01%±7.65%, 86.70%±5.66%, and 82.53%±1.39%, respectively. Miller classification I (n=12), II (n=10), and III (n=3) teeth showed mean coverage rates of 97.01%±7.65%, 86.91%±5.90%, and 83.19%±1.62%, respectively. At the donor sites, an average defect depth of 1.41 mm (70.5%) recovered in 3 weeks, and the wounds were epithelized completely in all cases. Conclusions The modified tunneling technique in this study is a promising treatment modality for overcoming GR in the anterior mandible., Graphical Abstract

Hematite supported on alumina or alumina/titania was fabricated to serve as an oxygen carrier in the chemical looping combustion (CLC) of charcoal. The reduction rate of Fe2O3/Al2O3 and Fe2O3/Al2O3/TiO2 particles increased with the reactor inlet’s CO concentration and displayed a slight effect from elevated operating temperatures. Applying the shrinking core model, the mass transfer coefficients (kg) for the reduction of Fe2O3/Al2O3 and Fe2O3/Al2O3/TiO2 by CO were found to be 0.16 and 0.22 mm s–1, respectively, and using the Fe2O3/Al2O3 and Fe2O3/Al2O3/TiO2 to combust charcoal resulted in carbon conversion rates of approximately 61.8% and 47.2%, respectively, when the inlet steam flow rate was set to 221.4 mmol min–1. Significantly, a higher inlet steam flow rate may not be advantageous when employing iron-based oxygen carriers. More heat was released during combustion with the Fe2O3/Al2O3 than with the Fe2O3/Al2O3/TiO2 due to a high flow rate for the former being used. When Fe2O3/Al2O3/TiO2 was used as the oxygen carrier, the particles, which contained a large percentage of Fe2O3, exhibited high reactivity to syngas (CO/H2); thus, less Fe2O3/Al2O3/TiO2 than Fe2O3/Al2O3 was required to combust the charcoal.

The design of diagnostics system for the Helium Cooled Ceramic Reflector (HCCR) Test Blanket System (TBS) has now progressed from generic approaches to the conceptual design integration phases. It is proposed to monitor the temperature, strain, magnetic field strength and neutron flux in selected positions of the corresponding Test Blanket Module (TBM). The temperature can be measured by thermocouple sensors to be integrated for the first wall and breeding zones of TBM. The strain will be monitored by appropriate gauges on the first wall of TBM. Several magnetic pick-up coils could be installed to measure magnetic field strength inside the TBM structure. For the neutron flux monitoring, pairs of Neutron Activation System (NAS) probes and Micro-Fission Chambers (MFCs) would be installed in the TBM structure. In this paper, a brief description on the proposed diagnostics system as well as the key components is presented, and the integration challenges of HCCR TBS diagnostics system are outlined.

Zirconia supported CuO oxygen carriers were prepared for carrying out chemical looping with oxygen uncoupling (CLOU) and chemical looping with air separation (CLAS) operation in a thermogravimetric analyzer (TGA), a fixed bed reactor and a moving bed reactor (MBR). In this study, graphite used as solid fuel for CLOU with CuO/ZrO2 oxygen carriers was also explored in a fixed bed reactor. 40 wt.% CuO/ZrO2 particles sintered at 1000 °C revealed reasonable reactivity without noticeable agglomeration as observed. For fixed bed operation, time required for graphite combustion with CuO/ZrO2 was decreased for experiments conducted at higher reaction temperatures. For experiments carried out in the moving bed reactor, the oxygen concentration and oxygen molar flow rate in the outlet stream can be adjusted by varying operating temperatures, CuO/ZrO2 flow rate, and carrier gas (N2) flow rate. Therefore, moving bed reactors are technically feasible to serve as fuel reactor for chemical looping with air separation.

The redox performances of 1–10 wt% Na-modified Fe2O3/Al2O3 oxygen carrier from seawater were investigated using syngas/air as reactive gases in the thermogravimetric analyzer (TGA) and lab-scaled semi-fluidized bed reactor (semi-FzBR). NaNO3(aq) as the source of sodium dopants to prepare Na-contained solution was implemented by an air atmospheric pressure plasma jet (Air-APPJ) process, which can increase the feasibility of seawater. For the prepared samples, the materials properties, including crystalline phases, surface morphologies, surface areas, and attrition loss performances were well correlated with the Na contents. The results indicated that the poor reduction kinetics and attrition resistance were obtained with the Na adjunction over 5 wt%, attributing to the sintering issue on excessive phases of Na2(Al, Fe)12O19 and Na(Al, Fe)O2 solid solution in the samples. Therefore, the slight incorporation of Na content in the Fe2O3/Al2O3 samples which improved the reduction rate was proved as the candidate oxygen carriers. Particularly, the Na content with 1 wt% in Fe2O3/Al2O3 sample (Na1FA32) can significantly promote the reduction behavior, thermal stability, and attrition resistance as compared to the raw Fe2O3/Al2O3 oxygen carrier. It is environmentally beneficial to use the Na1FA32 as oxygen carrier in a practical chemical looping combustion process.

Epitaxial SrRuO3 thin films were fabricated on (001) SrTiO3 substrates by using radio-frequency (RF) magnetron sputtering. The films were deposited on (001) SrTiO3 substrates with a 0.1°, 0.2°, 0.5° or 1.0° miscut angle. The fabrication temperatures of the SrRuO3 thin films were changed in the range of 500-650 °C for the miscut 0.1° (001) SrTiO3 substrates. X-ray diffraction confirmed cube-on-cube epitaxial structures of the SrRuO3 thin films on (001) SrTiO3. According to the atomic force microscopy (AFM) images, the SrRuO3 thin films, which had been deposited on miscut 0.1° (001) SrTiO3, grew by step flow along the miscut direction of the substrate. In case of higher miscut angle, the step height was higher than that of a single unit cell of SrRuO3 due to the step bunching process. The SrRuO3 thin films grown at 500 °C showed an island growth mode and those grown at temperatures higher than 550 °C showed a step flow growth mode.

Iron-based oxygen carriers supported on alumina or alumina/titania were prepared and evaluated for chemical looping combustion of methane. The reduction conversion of Fe2O3/Al2O3 and Fe2O3/Al2O3/TiO2 particles was markedly increased with increasing inlet concentration and was slightly enhanced by elevated operating temperatures. According to the shrinking core model, the mass transfer coefficients (kg) of Fe2O3/Al2O3 and Fe2O3/Al2O3/TiO2 reduction with methane are found to be 0.07 and 0.12 mm s−1. Complete combustion of methane is almost achieved for experiments conducted with Fe2O3/Al2O3 and Fe2O3/Al2O3/TiO2 operated as the Fe2O3/CH4 molar ratio reached about 5.4 and 4.4, respectively. Carbon deposition during methane combustion was avoided by using Fe2O3/Al2O3/TiO2 as an oxygen carrier. More heat was generated for the combustion of methane by Fe2O3/Al2O3/TiO2 oxygen carriers because methane more fully reacted with the Fe2O3 contained in the Fe2O3/Al2O3/TiO2 oxygen carriers.

Here, we report on reduced graphene oxide (rGO) electrode prepared by doctor-blading a viscous rGO paste on FTO substrate followed by sintering at 500 °C in argon and its application as a counter electrode (CE) of dye-sensitized solar cells (DSSCs). The paste was prepared by mixing rGO and ethyl cellulose in terpineol. The rGO was prepared from commercially available graphite flakes, which were first oxidized to graphene oxide (GO) by modified Hummers’ process and then the GO was reduced to rGO with hydrazine. Electrochemical analyses – cyclic voltammetry and electrochemical impedance spectroscopy – suggest that the performance of the rGO electrode towards I−/I3− is comparable to that of Pt electrode. Even though the catalytic performance of the rGO film towards the reduction of triiodide was not as good as thermally decomposed Pt electrodes, the overall series resistance of the rGO-based cell was similar to that of the Pt-based cell. When applied to DSSCs as a CE, the rGO electrode performs like a Pt electrode showing the prospect of replacing Pt with a metal-free all-carbon material.

Since the stress due to the thermal load on breeding blanket structure is one of the main design driver, the thermal conductivity is necessary input data for thermal-structural and thermo-hydraulic analyses performed in order to understand the heat transfer phenomena and estimate the thermal stress. Since for the functional materials of solid type breeding blanket a pebble-bed form is mainly adopted instead of a bulk form such as a block or a disk, it should be needed to measure the thermal conductivity of pebble-bed. In this study, the effective thermal conductivity of pebble-bed is measured by laser flash method, which is one of the various thermal conductivity measurement methods, because this method has several advantages such as a wide thermal conductivity range of the measurement and a small amount of pebbles. A sample holder considering the heat transfer mechanism from the laser source to pebble-bed has been specially designed in order to apply the laser flash technique to the pebble-bed sample and it has been validated by the experiments. This paper introduces preliminary results of the effective thermal conductivity on the pebble-bed using this sample holder.

TiO2 nanotube arrays (TNTs) were fabricated by anodization under various operational conditions. Dimensions of fabricated TNTs were significantly influenced by the temperature and water content of ...

Objective To evaluate the effect of different surgical techniques on primary stability, particularly in poor-quality bone with or without a crestal cortical bone. Materials and methods Three implant site preparation techniques-undersized drilling (UD), undersized drilling and coronal widening with a cortical drill (UD + CD), undersized drilling and coronal tapping with a cortical tap (UD + CT)-were compared in 2 different low-density polyurethane bone models either with or without the crestal cortical bone. Insertion torque values (ITVs) for each technique was recorded. Results Statistically significant difference was observed for all 3 surgical techniques. In the presence of a crestal cortical bone, the peak ITV for UD was the highest, UD + CT the second, and UD + CD the lowest. All peak ITVs remained significantly lower in the absence of a crestal cortical bone. Conclusion Our findings suggested that UD + CTmay be the most effective implant surgical technique to achieve an ideal primary stability in low-density bone with a thin crestal cortical bone layer. Also, this technique may prevent compression necrosis of the dense cortical bone.

Ultraviolet (UV) photofunctionalization has been suggested as an effective method to enhance the osseointegration of titanium surface. In this study, machined surface treated with UV light (M + UV) was compared to sandblasted, large-grit, acid-etched (SLA) surface through in vitro and in vivo studies. Groups of titanium specimens were defined as machined (M), SLA, and M + UV for the disc type, and M + UV and SLA for the implant. The discs and implants were assessed using scanning electron microscopy, confocal laser scanning microscopy, electron spectroscopy for chemical analysis, and the contact angle. Additionally, we evaluated the cell attachment, proliferation assay, and real-time polymerase chain reaction for the MC3T3-E1 cells. In a rabbit tibia model, the implants were examined to evaluate the bone-to-implant contact ratio and the bone area. In the M + UV group, we observed the lower amount of carbon, a 0&deg, degree contact angle, and enhanced osteogenic cell activities (p &lt, 0.05). The histomorphometric analysis showed that a higher bone-to-implant contact ratio was found in the M + UV implant at 10 days (p &lt, 0.05). In conclusion, the UV photofunctionalization of a Ti dental implant with M surface attained earlier osseointegration than SLA.

Using a conceptual design of the Korean helium cooled ceramic reflector (HCCR) test blanket module (TBM) including the TBM-shield for testing in ITER, a structural analysis with electro-magnetic (EM) loads is performed. From a previous analysis of the material magnetization due to the use of reduced activation ferritic-martensitic (RAFM) steel as the TBM structure material and EM analysis considering the major disruption of MD-I, MD-II, and MD-IV, the forces are obtained and used for the current structural analysis. The results indicate that the maximum stress occurs at the He purge line at the upper and lower region of the breeding zone (BZ) box including the graphite reflector region, which meets the design requirement. In addition, displacements are lower than the designed gaps from the TBM port plug (PP) frame. The results are provided to the load combination analysis.

TiO2 nanotube arrays (TNTs) were modified with copper indium sulfide (Cu/In/S) by successive ionic layer adsorption and reaction (SILAR) method. The field-emission scanning electron microscopy and X-ray photoelectron spectroscopy analysis demonstrated the presence of copper indium sulfide nanoparticles on the surface of the modified TNTs. The Cu/In/S-modified TNTs exhibited higher photocurrent density and photocatalytic activity than plain TNTs. The concentration of sulfur precursor was found to be an important factor on the composition of modified Cu/In/S films by SILAR. Some composition deviations were observed on the stoichiometry of the Cu/In/S-modified TNTs, which evidently affected the electrochemical characteristics of the modified TNTs. Experiments using the modified TNTs of composition close to the stoichiometric ratio of CuInS2 usually delivered higher photocatalytic decomposition of gaseous isopropyl alcohol in air streams and exhibited better stability during operation.

Fe_2O_3/Al_2O_3 and Fe_2O_3/TiO_2/Al_2O_3 oxygen carriers were fabricated and evaluated for chemical looping hydrogen generation (CLHG) using a TGA system and a fixed-bed reactor. Oxygen carriers were converted to around 33% in a fixed-bed reactor to ensure uniform reduction. The reduced oxygen carrier was tested for steam generation, where in all cases Fe_2O_3/Al_2O_3 displayed a better conversion than Fe_2O_3/TiO_2/Al_2O_3. It was found that increasing the reaction temperature from 800 to 850 °C had little effect for either oxygen carrier, but a further increase to 900°C resulted in an increased steam conversion. A higher steam flow rate caused a lower overall steam conversion but a higher H_2 production. A higher feed rate of reduced oxygen carrier let to a higher steam conversion up to a rate of 18.4 and 14.9 g min^(-1) for Fe_2O_3/Al_2O_3 and Fe_2O_3/TiO_2/Al_2O_3, respectively. A final comparison was performed with up to 50 redox cycles, where Fe_2O_3/Al_2O_3 showed superior reactivity in the first cycles but ended at a conversion of 54.6% with Fe_2O_3/TiO_2/Al_2O_3 ending at a conversion of 64.6%.

Iron-based oxygen carriers supported on alumina or alumina/titania were fabricated and evaluated for chemical looping combustion of isopropanol (IPA). Hydrogen is the major combustible gas generated by IPA decomposition prior to combustion with oxygen carriers at temperatures above 800°C. Nearly complete combustion (above 95%) of IPA was achieved for experiments conducted with fabricated Fe2O3/Al2O3 and Fe2O3/Al2O3/TiO2 operated at lower inlet IPA flow rates. Carbon deposition during the chemical looping combustion of IPA was minimized using Fe2O3/Al2O3/TiO2 as an oxygen carrier. The reduction of Fe2O3/Al2O3 and Fe2O3/Al2O3/TiO2 by hydrogen was markedly increased with increasing inlet hydrogen concentration (5–20%), and was not obviously influenced by operating temperature (875–925°C). According to the shrinking core model, the mass transfer coefficients (kg) of Fe2O3/Al2O3 and Fe2O3/Al2O3/TiO2 reduction with H2 were found to be 0.22 and 0.24 mm s–1, while the effective diffusion diffusivity (De) of Fe2O3/Al2O3 oxygen carriers was more easily depended on the oxygen carrier conversion. The higher reduction conversions obtained for experiments conducted with Fe2O3/Al2O3/TiO2 because it can be further reduced to FeO and Fe; comparing to those with Fe2O3/Al2O3, which is primarily reduced to FeO. Hydrogen molecules are found to diffuse more easily through the FeO product-layer on Fe2O3/Al2O3 than the FeO/Fe product-layer on Fe2O3/Al2O3/TiO2.

The application of controlled periodic illumination (CPI) using ultraviolet light-emitting diodes (UV-LED) for the photocatalytic reduction of CO2 in the aqueous phase was investigated in this study. The experiments were conducted with P-25 TiO2 as photocatalyst under the UV light intensity of 160 mW/cm2 with 60 min of total illumination time and pH 2. The target product of the photocatalytic reduction of CO2 by UV-LED process was methanol with the highest selectivity of 28.31 %. The reduction efficiency of CO2 and the reaction rate reached the highest value of 86.31 % and 15.76 × 10−5 M min−1, respectively, for experiment conducted with the smallest duty cycle of 0.09. The photonic efficiency was enhanced from 0.47 % to 2.7 % with decreasing duty cycle from 1.00 to 0.09. The electric energy saving increased significantly from 13.11%–93.34%, including with a decrease of electric energy per order from 139.68 to 10.71 kW h m-3 order-1 for experiments conducted with decreasing γ from 0.91 to 0.09. The photocatalytic reduction of CO2 in the aqueous phase was well modeled by the Langmuir-Hinshewood kinetic equation. Furthermore, the proposed mechanism for photocatalytic CO2 reduction in aqueous phase under CPI was introduced.

자주박격포는 보병에 의해 운용되는 도수운반 박격포와 달리 박격포를 전투차량에 탑재한 무기 체계이다. 자주박격포는 도수운반 박격포에 비해 Key Words: Self-Propelled Mortar(자주박격포), Multibody Dynamic Analysis(다물체동역학 해석), Interior Ballistic(강내탄도학), External Ballistic(강외탄도학), Accuracy of Fire(사격정확도) 초록: 본 연구에서는 자주박격포의 다물체동역학 모델을 만든 뒤, 포탄의 탄도학을 고려하여 시뮬레이션 하였다. 자주박격포 모델은 박격포 모델 및 차량 모델로 구성하였으며, 상용 다물체 해석 프로그램인 RecurDyn 을 사용하였다. 차량 모델은 6 자유도 강체플랫폼으로 모델링 하였으며, 박격포 발사 직후의 움직임에는 강내탄도학을 적용하였다. 강내탄도학 해석의 결과를 바탕으로, 포신을 떠난 후의 강외탄도 해석을 수행하였다. 몬테카를로 기법을 활용한 반복 해석으로 발사각과 차량 동특성에 의한 변동이 고려된 탄착점의 분산도를 구하여 사격정확도를 제시하였다. Abstract: For this research, the trajectory of a projectile was simulated via the multibody dynamics analysis of a self-propelled mortar. The dynamic model was composed of a mortar model and a vehicle model, and was simulated using the RecurDyn program. Interior ballistic was applied to the mortar model, and exterior ballistic was conducted by Matlab using the simulation results of the interior trajectory. Through repetitive Monte-Carlo simulations, the accuracy of the mortar was analyzed by considering variations in the aiming angle and vehicle dynamic response.

The characteristics and application of TiO2-supported Fe2O3 oxygen carriers were investigated for chemical looping combustion (CLC) and hydrogen generation (CLHG) in this study. Prepared Fe2O3/TiO2 oxygen carriers with 20–30 wt% of TiO2 were demonstrated to achieve satisfactory results even after 30-cycle operation by thermogravimetric analyzer (TGA). Oxygen carriers contain more than 33 wt% TiO2 were observed to be more porous and fragile after continuous high-temperature operation. Conversely, the reactivity of oxygen carriers contain less 10 wt% TiO2 was rapidly decayed after operated for merely 3 redox cycles because of their dense structure. The CO2 and H2 conversions through syngas combustion and steam oxidation, respectively, for experiments were demonstrated to be feasible using sieved oxygen carriers at higher operation temperatures from 400 to 1000°C in fixed bed reactor (FBR) system.

Rice husk used as solid fuel for chemical looping combustion (CLC) with Fe2O3/Al2O3 oxygen carriers was investigated in an annular dual-tube moving bed reactor (ADMBR). Nearly 100% of CO2 concentration and 92% fuel conversion were achieved for rice husk combustion conducted with Fe2O3/Al2O3 mass flow rates of 22.7 g/min. The introduction of rice husk/sawdust and rice husk/charcoal and mixtures enhanced the processing capacity because of the higher carbon content. The heat demands for ADMBR were estimated to be roughly 54% of input processing capacity released for both rice husk and rice husk/sawdust gasification, while about 19% of input processing capacity was released for rice husk/charcoal gasification. ADMBR is technically feasible to be served as the fuel reactor for rice husk combustion by CLC to achieve high fuel conversion under appropriate operating conditions without auxiliary fuel.

Korean Helium Cooled Ceramic Reflector (HCCR) Test Blanket Module (TBM) will be installed at the #18 equatorial port of the Vaccum Vessel in order to test the feasibility of the breeding blanket performance for forthcoming fusion power plant in the ITER TBM Program. Since ITER tokamak contains Vaccum Vessel and set of electromagnetic coils, the TBM as well as other components is greatly influenced by magnetic field generated by these coils. By the electromagnetic (EM) fast transient events such as major disruption (MD), vertical displacement event (VDE) or magnet fast discharge (MFD) occurred in tokamak system, the eddy current can be induced eventually in the conducting components. As a result, the magnetic field and induced eddy current produce extremely huge EM load (force and moment) on the TBM. Therefore, EM load calculation is one of the most important analyses for optimized design of TBM. In this study, a 20-degree sector model for tokamak system including central solenoid (CS) coil, poloidal field (PF) coil, toroidal field (TF) coil, vaccum vessel, shield blankets and TBM set (TBM, TBM key, TBM shield, TBM frame) is prepared for analysis by ANSYS-EMAG tool. Concerning the installation location of the TBM, a major disruption scenario is particularly applied for fast transient analysis. The final goal of this study is to evaluate the EM load on HCCR TBM during plasma major disruption.

It was indicated that tetragonal zirconia polycrystal (TZP) containing yttria (Y2O3) and niobium oxide (Nb2O5) ((Y,Nb)-TZP) could be an adequate dental material to be used at esthetically important sites. The (Y,Nb)-TZP was also proved to possess its osteogenic potential comparable with those conventional dental implant material, titanium (Ti). The objective of the current study was to characterize cellular response of human gingival fibroblasts (HGFs) to smooth and rough surfaces of the (Y,Nb)-TZP disc, which were obtained by polishing and sandblasting, respectively. Various microscopic, biochemical, and molecular techniques were used to investigate the disc surfaces and cellular responses for the experimental (Y,Nb)-TZP and the comparing Ti groups. Sandblasted rough (Y,Nb)-TZP (Zir-R) discs had the highest surface roughness. HGFs cultured on polished (Y,Nb)-TZP (Zir) showed a rounded cell morphology and light spreading at 6 h after seeding and its proliferation rate significantly increased during seven days of culture compared to other surfaces. The mRNA expressions of type I collagen, integrin α2 and β1 were significantly stimulated for the Zir group at 24 h after seeding. The current findings, combined with the previous results, indicate that (Y,Nb)-TZP provides appropriate surface condition for osseointegration at the fixture level and for peri-implant mucosal sealing at the abutment level producing a suitable candidate for dental implantation with an expected favorable clinical outcome.

In this work, a simple and a straight-forward approach to derive the parameters of dye-sensitized solar cells (DSSCs) in terms of single diode model is discussed. The parameters are extracted exclusively from single current density–voltage (j–V) curve with some common assumptions. The technique does not require smoothing of the j–V curve by means of polynomial fitting as well as iterative calculation of the diode model equation. The data obtained from this method are compared with that obtained from least square fitting and the combined analyses of electrochemical impedance spectroscopy (EIS) and j–V data for two different DSSCs. The method is suitable for routine analysis of DSSCs.

Chemical looping hydrogen generation (CLHG), as a new technology involved in chemical looping combustion (CLC) process and steam-iron process, has attracted attention for clean energy generation and efficient energy conversion. A systematic investigation of spinel NiFeAlO4 has led to characterization of a well-defined self-supported oxygen carrier which was prepared by solid state reaction. The redox behavior of NiFeAlO4 shows the enhancement on the resistance to agglomeration exceeding previously reported CLC process using similar compositions including Fe2O3, NiO and NiFe2O4 without any inert support. Moreover, the high CO2 conversion and H2 generation by NiFeAlO4 oxygen carrier under a fixed-bed reactor (FxBR) were obtained. The reaction mechanism of NiFeAlO4 subjected to the isothermal stepwise reduction in a sequence of varying durations by XRD was also demonstrated, which provided with a novel function of self-supported and agglomeration-resistant characteristic in the oxygen carrier system.

In this study, the bone regeneration efficacy of dehydrothermally (DHT) cross-linked collagen membrane with or without a bone graft (BG) material was evaluated in a critical-sized rat model. An 8-mm-diameter defect was created in the calvaria of 40 rats, which were randomized into four groups: (1) control; (2) DHT; (3) BG; and, (4) DHT + BG. Evaluations were made at 2 and 8 weeks after surgery using micro-computed tomographic (micro-CT), histological, and histomorphometric analyses. Micro-CT analysis showed an increase in the new bone volume (NBV) of the BG and DHT + BG groups at 2 weeks after surgery, representing a significant difference (p < 0.05). At 8 weeks after surgery, the NBV increased in all four groups. However, larger NBVs were observed in the BG and DHT + BG groups, and a significant difference was no longer observed between the two groups. Histologic analysis demonstrated that the graft materials sustained the center of the defect in the BG and DHT + BG groups, which was shown in histomorphometric analysis as well. These results suggest that DHT membrane is a safe biomaterial with adequate tissue integration, and has a positive effect on new bone formation. Moreover, the best effects were achieved when DHT was used in conjunction with BG materials.

Polyurethane (PU) and polypropylene (PP) particles were evaluated as solid fuels in chemical looping combustion (CLC) for treatment of waste plastics as well as power generation. An annular duel-tube moving bed reactor (ADMBR) was used as fuel reactor for decomposition and combustion of PU and PP particles. CO and H 2 were the major components of fuel gas generated by decomposition of PU and PP particles in the ADMBR. Complete conversion of plastic particles and 100% CO 2 yield of fuel gas were achieved as oxygen carrier-to-fuel ratio of PU and PP particles reached 1.86 and 6.56, respectively. The heat demands for ADMBR were calculated to be 21% and 52% of output processing capacity by heat consumptions of fuel decomposition in the fuel reactor of CLC system, respectively. ADMBR is technically feasible as fuel reactor for PU and PP combustion to achieve high conversion efficiency without auxiliary fuel by CLC.

Korea plans to test a Helium Cooled Ceramic Reflector (HCCR) Test Blanket Module (TBM) in ITER. The HCCR TBM adopts a four sub-module concept considering the fabricability and the transfer of irradiated TBM for post irradiation examination. Each sub-module has seven-layer breeding zone, including three neutron multiplier layers packed with beryllium pebbles, three lithium ceramic pebble bed packed tritium breeder layers, and a reflector layer packed with graphite pebbles. Based on this configuration, neutronic and electromagnetic calculations were performed and their results were applied for the conceptual design of HCCR TBM that considers manufacturing feasibility. Also, a design and safety analysis of HCCR Test Blanket System (TBS) was performed using integrated design tools modifying nuclear system codes for helium coolant and tritium behavior evaluation. The Advanced Reduced Activation Alloy (ARAA) is being developed as a structural material. A total of 73 candidate ARAA alloys were designed and their out-of-pile performance was evaluated. The graphite pebbles as the neutron reflector were fabricated by using mechanical machining and grounding method with the surface coated with SiC. The hydrogen permeation characteristics of structural materials were evaluated using the Hydrogen PERmeation (HYPER) facility. The recent design and R&D progress on these areas are addressed in this paper.

Fe2TiO5 was studied for the reduction mechanism in chemical looping process. Fe2TiO5 pellets were reduced by syngas that demonstrated highest reduction rate in the beginning of reduction period from Fe2TiO5 to FeTiO3 and Fe2TiO4. The reduction of Fe2TiO5 is suggested in sequence from Fe2TiO4, FeTiO3 to Fe. Fe2TiO5 pellets performed reasonable reactivity and steady recyclability after continuous 100 redox cycles. The increased surface area and decreased mechanical strength for pellets operated after 30 redox cycles was due to formation of cracks and porous structures. Moreover, Fe2O3/TiO2 was the major crystalline phase existed in the pellets after 30 redox cycles. Fe2TiO5 attributed high syngas conversion in the fixed bed reactor due to high equilibrium constants. The completed reduced form of Fe2TiO5 oxygen carriers, Fe/TiO2, demonstrated hydrogen generation by steam oxidation, and the Fe was oxidized to Fe3O4 and FeTiO3 in the fixed bed reactor.

The initial stability of a dental implant is known to be an indicator of osseointegration at immediate loading upon insertion. Implant designs have a fundamental role in the initial stability. Although new designs with advanced surface technology have been suggested for the initial stability of implant systems, verification is not simple because of various assessment factors. Our study focused on comparing the initial stability between two different implant systems via design aspects. A simulated model corresponding to the first molar derived from the mandibular bone was constructed. Biomechanical characteristics between the two models were compared by finite element analysis (FEA). Mechanical testing was also performed to derive the maximum loads for the two implant systems. CMI IS-III active (IS-III) had a more desirable stress distribution than CMI IS-II active (IS-II) in the surrounding bone region. Moreover, IS-III decreased the stress transfer to the nerve under the axial loading direction more than IS-II. Changes of implant design did not affect the maximum load. Our analyses suggest that the optimized design (IS-III), which has a bigger bone volume without loss of initial fixation, may minimize the bone damage during fixture insertion and we expect greater effectiveness in older patients.

The degree of misfit between a prosthesis and its supporting implants is a major concern in screw-retained prostheses because it can lead to screw loosening or mechanical failure of implant components. On the other hand, the difficulty of removing subgingival excess cement and the irretrievability of the superstructure are major drawbacks to cement-retained prostheses. A newly designed screw- and cement-retained prosthesis (SCRP) may solve these problems with its passivity, retrievability, and ease in the complete removal of excess cement, giving it the advantages of both screw-retained and cement-retained prostheses. This prosthetic system is mainly composed of a cement-retained framework with screw holes on the occlusal surface and specially designed cementable abutments for multiunit prostheses. The principle and structure of the SCRP system is described in this article.

Chemical-looping combustion (CLC) of fossil fuel has a potential to generate power with achieving the inherent CO2 capture by means of an oxygen carrier (OC) that is circulated between air and fuel reactors. In this article, a composite oxygen carrier with highly redox reactivity for chemical-looping combustion process was first synthesized using nickel nitrate and iron nitrate as precursors in a sol–gel process, respectively. Materials characterization of the prepared OC samples were investigated by X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) surface area measurements, scanning electron microscopy (SEM), and energy dispersive X-ray (EDX). The reactivity of the oxygen carrier in CLC process was evaluated by a thermogravimetric analyzer by alternating methane and air. The prepared nickel–iron composites oxygen carrier exhibited excellent oxygen-transfer capability both in the fuel and air reactors than pure Fe2O3, NiO, NiFe2O4, and physically mixed Fe2O3–NiO samples. The synergistic effect between Fe and Ni cations can enhance the reduction rate of iron oxide; meanwhile, it also improves the oxidation reaction rate of metallic nickel. The different migration behaviours of iron and nickel under the reducing and oxidizing atmospheres were observed by XRD and EDX, respectively. Finally, twenty-cycles of redox reaction demonstrated that composites oxygen carrier loaded on the SiC inert support had excellent redox activity and sintering resistance and consequently was capable of the CLC process.

Korea plans to install and test Helium Cooled Ceramic Reflector (HCCR) Test Blanket Module (TBM) in the ITER, because the HCCR blanket concept is one of options of the DEMO blanket. Currently, many design and R&D activities have been performed to develop the Korean HCCR TBM. An integrated design tool for a fusion breeder blanket has been developed based on nuclear technologies including a safety analysis for obtaining a license for testing in the ITER. A half-scale sub-module mockup of the first wall with the manifold was fabricated, and the manufacturability and thermo-hydraulic performances were evaluated. High heat load and helium cooling test facilities have been constructed. Next, the recent status of TBM material development in Korea was introduced including Reduced Activation Ferritic Martensitic (RAFM) steel, lithium ceramic pebbles and silicon carbide (SiC) coated graphite pebbles. Several fabrication methods of RAFM steel, lithium ceramic pebbles, and silicon carbide coating on graphite pebbles were investigated. Recent design and R&D progress on these areas are introduced here.

The aim of this study is to fabricate TiO 2 nanotubes arrays (TNTs) with smooth homogenous morphology by the anodization of titanium foil in fluorine-contained electrolytes. A series of materials analysis techniques, such as field-emission scanning electron microscopy, potentiostat/galvanostat and X-ray diffractometer, are used to characterize the surface morphology, phase formation, lattice parameters and the induced photocurrent intensity of TNTs. As the experimental results, the tube dimension of TNTs is found to be determined by the migration and diffusion of ions in the electrolyte corresponding to the concentration profiles of oxygen-containing anionic species and hydrogen ions within the TiO 2 nanotubes. High-aspect-ratio TNTs with a superior degree of regularity and homogeneity are favored to be formed in the fluoride-contained ethylene glycol solutions due to the suppression of pH bursts and local ions concentration fluctuations during anodization in the highly viscous electrolytes. To compare the NO reduction by photo-SCR using spherical TiO 2 (P25) and tubular TiO 2 , the performance of NO reduction by photo-SCR is significantly affected by the available surface area (active sites) of TiO 2 rather than the crystal composition of TiO 2 .

Material is a crucial factor for the restoration of the tooth or periodontal structure in dentistry. Various biomaterials have been developed and clinically applied for improved periodontal tissue regeneration and osseointegration, especially in periodontology and dental implantology. Furthermore, the biomimetic approach has been the subject of active research in recent years. In this review, the most widely studied biomaterials (bone graft material, barrier membrane, and growth or differentiation factors) and biomimetic approaches to obtain optimal tissue regeneration by making the environment almost similar to that of the extracellular matrix are discussed and specifically highlighted.

Highly-ordered TiO2 nanotube arrays (TNTs) were prepared by anodisation in ethylene electrolytes containing 0.2–0.7 wt% NH4F. The dimension, chemical composition and optical characterisation of prepared TNTs were determined by the field-emission scanning electron microscopy, X-ray photoelectron spectroscopy and photoluminescence spectroscopy, respectively. Both the length and inner diameter of the prepared TNTs were increased with increasing NH4F concentration of electrolyte because of the faster electrochemical dissolution rate of TiO2. However, dimension of TNTs approached stable lengths and inner diameters as the NH4F concentration was higher than 0.3 wt%. The presence of Ti3+ state was observed for TNTs prepared with increasing NH4F concentration because of the charge compensation of the substitution of fluoride ions for oxygen ions. TNTs prepared in the electrolytes containing higher NH4F concentrations exhibited superior performance on the photocatalytic decomposition of Acid Red 4 possibly because more fluorides incorporated with TNTs to inhibit the recombination of electron–hole pairs.

Several R&Ds are being performed for Korean helium cooled solid breeder (HCSB) test blanket module (TBM) in the field of hydrogen isotopes permeation characteristics measurement in the helium purge line, joining technologies of structural materials, breeder pebble materials development, and the measurement of pebble bed characteristics. Electron beam welding for reduced activated ferritic–martensitic (RAFM) steel is evaluated to find optimal welding conditions. Also, a hydrogen permeation measurement apparatus is newly installed for the evaluation of the permeation barrier characteristics of stainless steel and RAFM steels. Two fabrication methods of lithium orthosilicate pebbles are investigated using slurry droplet methods. As methods of silicon carbide coating on the graphite pebble, microwave coating and chemical vapor deposition coating are evaluated. Two apparatuses are established to assess the thermo-mechanical properties of graphite and breeder pebble beds. The current status of R&D activities on these areas is introduced and the main progresses are addressed in this paper.

This paper describes the effect of polyhedral oligomeric silsesquioxane (POSS) in anisotropic conductive films (ACFs) composition on the material properties and reliability of ACF interconnections for chip-on-glass (COG) applications. Series of POSS modified ACFs containing 0wt%, 2wt%, 4wt%, 6wt% and 8wt% contents of octa-methacrylated POSS were formulated and characterized. The POSS added in the formulations favorably affected on the materials properties of ACFs by lowering coefficient of thermal expansion (CTE) and increasing modulus (E′). In addition, an increase in the POSS contents led to higher curing density and, as a result, thermo-mechanical properties of ACFs were improved. But, the adhesion strength of ACF materials was decreased with the POSS content, due to higher modulus originated from octa-functional POSS. The reliability performances of COG assemblies using POSS modified ACFs were also investigated. In conclusion, the materials properties and module reliability of COG assemblies were impr...

R&D activities currently being undertaken for Korean Helium Cooled Solid Breeder (HCSB) Test Blanket Module (TBM) include joining technologies of structural materials, breeder pebble material development, and measurement of pebble bed characteristics. The joining performance of ferritic–martensitic steel is evaluated. TIG welding for ferritic–martensitic steel is evaluated to find welding conditions with two different current modes. The fabrication methods of lithium silicate powder and lithium titanate pebble are under development using special process. The Li2TiO3 pebbles showing an average diameter of 1.8 mm was fabricated by water-based sol–gel method. The Li4SiO4 powder with the particle size of about 200 nm was synthesized by PVA polymer solution method. The method of silicon carbide coating on the graphite pebble is investigated, and its possibility is verified based on the coating results on the graphite plate. Sputtered SiC coating layer was crystallized by high temperature heat treatment. The measurement method and database of the thermal properties of the pebble and pebble bed are important for the design of TBM as well as breeding blanket. The initial characteristics of the pebbles are assessed measuring the effective thermal diffusivity of graphite pebble by laser flash method.

Thermo-hydraulic design of test blanket module (TBM) is challenging in that each component of TBM should be properly controlled within narrow temperature margins in the extreme conditions such as high heat flux from plasma and volumetric heat generation due to neutron irradiation. This paper presents thermo-hydraulic analysis results on the Korean helium cooled solid breeder (HCSB) TBM with the updated design. In the previous study, computation was performed on the TBM model with assumption that the coolant is uniformly distributed at back manifolds, without including the back manifolds in the computational model. In the present study, the updated configuration of the back manifolds is introduced. Flow distribution in each manifold is investigated as well as flow characteristics. Then, thermo-hydraulic analysis on the TBM model is carried out with flow distributions calculated from the flow analysis results on the back manifolds. It is found that the current manifolds are reasonably designed so that the TBM components are effectively cooled against associated thermal loads.

Korea is developing a Helium Cooled Solid Breeder Test Blanket Module for ITER. The primary candidate structural material is a Reduced Activation Ferritic/Martensitic steel. The complex TBM structure requires developing joining technologies for successful fabrication. The characteristics of Tungsten Inert Gas welding and Hot Isostatic Pressing joining of RAFM steel were investigated. Metallurgical examinations showed that the steel grain size was increased after HIP joining and recovered by post joining heat treatment. Both TIG welding and HIP joining are found to be acceptable for ITER TBM based on mechanical tests and microstructure examination.

Thin films of pure TiO2, silver-deposited TiO2, and platinum-deposited TiO2 were prepared on quartz substrates by a dip-coating process for the photodecomposition of o-cresol under light emitting diodes (LEDs) irradiation instead of a traditional lamp. In this work, effects of noble metal doping, periodic illumination, and LEDs wavelength on the photoactivity, electrical energy consumption, and quantum yield were explored in an effort to better understand the roles of noble metal and LEDs characterization in photocatalytic reactions. Degradation of o-cresol under LED irradiation increased with the decreased wavelength of LEDs, due to the higher power energy of a photon. Pt/TiO2 films on quartz substrates prepared by a photodeposition method exhibited excellent optical characteristics, energy savings, and visible light–induced photocatalytic properties compared with Ag/TiO2 and pure TiO2 (P25). EEO increased from 22 to 31 kWh/m3/order indicating that energy consumption for periodic illumination wa...