Design and performance analysis of structural components for a Korean He Cooled Ceramic Reflector TBM in ITER

Korea has developed a Helium Cooled Ceramic Reflector (HCCR) Test Blanket Module (TBM) testing in ITER, which was considered one of the fusion DEMO-relevant blankets in Korea. The design and performance analysis of the TBM body have been carried out considering the uniqueness of the KO TBM and design requirements by the IO and KO design concept: (1) KO TBM has 4 sub-modules considering a post irradiation test (PIE) and its delivery. (2) A first wall (FW) design was changed into a 15 × 11 rectangular shape and its performance was confirmed by thermal-hydraulic and thermo-mechanical analyses using commercial ANSYS code. The results showed that the revised design model satisfied 1.5S_m and 3S_m of the allowable stress (S_m) in the RCC-MR code at the maximum stress region of the components for mechanical and thermo-mechanical analyses, respectively. (3) Considering the tritium breeding and cooling, a breeding zone (BZ) design was investigated. Three Li and Be layers, and one graphite layer, were proposed by the iteration, and the appropriate temperature distribution was obtained. The design for other components such as a side wall (SW) and back manifold (BM) is on-going considering 9 MPa of channel pressure and its functions of flow distribution as a manifold.     

Determination of free acetaldehyde in total blood for investigating the effect of aspartate on metabolism of alcohol in mice

The cerebral cortex of anaesthetised 2- to 12-day-old rats was superfused with artificial cerebrospinal fluid containing 100 mM acetate substituted for chloride to condition the brain for spreading depression (SD). After such superfusion, the earliest SD-like events were found at day 9 and full blown SD at day 10, whereas in the unconditioned brain the first SD occurred between days 12 and 15. Acetate conditioning of the cerebral cortex may be used to unmask neuronal and glial properties that are hidden in early stages of development.     

A new on-chip interconnect crosstalk model and experimentalverification for CMOS VLSI circuit design

A new, simple closed-form crosstalk model is proposed. The model is based on a lumped configuration but effectively includes the distributed properties of interconnect capacitance and resistance. CMOS device nonlinearity is simply approximated as a linear device. That is, the CMOS gate is modeled as a resistance at the driving port and a capacitance at a driven port. Interconnects are modeled as effective resistances and capacitances to match the distributed transmission behavior. The new model shows excellent agreement with SPICE simulations. Further, while existing models do not support the multiple line crosstalk behaviors, our model can be generalized to multiple lines. That is, unlike previously published work, even if the geometrical structures are not identical, it can accurately predict crosstalk. The model is experimentally verified with 0.35-μm CMOS process-based interconnect test structures. The new model can be readily implemented in CAD analysis tools. This model can be used to predict the signal integrity for high-speed and high-density VLSI circuit design     

Steam reforming of liquefied natural gas (LNG) for hydrogen production over nickel–boron–alumina xerogel catalyst

A series of mesoporous nickel–boron–alumina xerogel (x-NBA) catalysts with different boron/nickel molar ratio (x = 0–1) were prepared by an epoxide-driven sol–gel method. The effect of boron/nickel molar ratio on the catalytic activities and physicochemical properties of nickel–boron–alumina xerogel catalysts was investigated in the steam reforming of liquefied natural gas (LNG). All the mesoporous x-NBA catalysts showed similar surface area. Introduction of boron increased interaction between nickel and support. In addition, introduction of boron into x-NBA catalysts reduced methane activation energy and increased nickel surface area. Promotion of boron had a positive effect on the catalytic activity due to the increase of adsorbed methane and nickel surface area. The amount of adsorbed methane and nickel surface area exhibited volcano-shaped trends with respect to boron/nickel molar ratio. LNG conversion and hydrogen yield increased with increasing the amount of adsorbed methane and with increasing nickel surface area. Among the catalysts, 0.3-NBA, which retained the largest amount of adsorbed methane and the highest nickel surface area, showed the best catalytic performance. It was also revealed that x-NBA catalysts showed strong coke resistance during the steam reforming reaction.     

A fully integrated 24-dBm CMOS power amplifier for 802.11a WLAN applications

A fully integrated 24-dBm complementary metal oxide semiconductor (CMOS) power amplifier (PA) for 5-GHz WLAN applications is implemented using 0.18-/spl mu/m CMOS foundry process. It consists of differential three-stage amplifiers and fully integrated input/output matching circuits. The amplifier shows a P/sub 1/ of 21.8 dBm, power added efficiency of 13%, and gain of 21 dB, respectively. The saturated output power is above 24.1 dBm. This shows the highest output power among the reported 5-GHz CMOS PAs as well as completely satisfying IEEE 802.11a transmitter back off requirement.     

New hardware architecture for fast raster image generation

Describes a new hardware architecture known as an edge painting tree (EPT) pipelined binary trees for fast generation of scanline images for raster scan graphics targeted for surface or solid modelling. The hardware complexity of EPT is much smaller than that of earlier raster graphics engines owing to the use of 1 bit logic rather than log₂ P bit logic where P is the number of pixels per scanline     

Effect of processing conditions on functional properties of collagen powder from skate (<Emphasis Type="Italic">Raja kenojei</Emphasis>) skins

Optimum conditions for collagen extraction from skate (Raja kenojei) skins with various liming concentrations, extraction solution pH, extraction temperature and time, and functional properties were investigated. The optimum conditions for collagen extraction are as combination of place the skins in a lime solution of 0.15 N of NaOH, extract with 5 volumes water (pH 4.0) for 4 hr at 40°C, filter, centrifuge, and lyophilize to obtain collagen powder. The characteristics of skate skin collagen obtained under optimum extraction conditions were: solubility 82.7%, turbidity 0.28, and Hunter color L, a, and b values were 88.4, 0.92, and 11.2, respectively. On the other hand, the acidic pH values (3.0 and 5.0) of collagen were more resistant to precipitation upon extended heating.     

Prevalence and characteristics of Escherichia coli O26 and O111 from cattle in Korea

Enterohemorrhagic Escherichia coli (EHEC) is an important cause of diarrhea, hemorrhagic colitis and hemolytic uremic syndrome worldwide. E. coli O26 and O111 are the serotypes most frequently isolated from human EHEC infections in Korea. Cattle are considered to be the major sources of E. coli O26 and O111. This study investigated the prevalence of E. coli O26 and O111 in fecal samples from cattle in Korea from April 2002 to March 2004. Out of 809 samples, 54 (6.67%), 37 (4.57%), and 16 (1.98%) tested positive for O26, O111, and both O26 and O111, respectively. Most of the E. coli O26 and O111 strains were isolated from May to October of each year. PCR analysis of the EHEC virulence markers revealed that most of the E. coli O26 and O111 isolates were positive for ehxA, eaeA and stx1 and/or stx2. These results suggest that the majority of Korean E. coli O26 and O111 isolates from cattle can cause serious diseases in humans.     

CFD-assisted scaling methodology and thermal-hydraulic experiment for a single spent fuel assembly

A computational fluid dynamics (CFDs)-assisted scaling methodology is proposed for a TN24P cask (Creer et al., 1987). In the proposed methodology, the height and the number of assemblies were scaled down based, respectively, on the integral scaling criteria by Ishii and Kataoka (1984) for a natural-circulation loop under single phase flow and on the concept of an insulator on the surface of the basket. The controlling scaling parameters for the TN24P cask (the scaling ratio of the heat flux, 1.6; the thickness and conductivity of the insulator, 9 mm and 0.05 W/m K, respectively) were estimated by comparing the results of a TN24P cask experiment (Creer et al., 1987) with those of a CFD simulation of a TN24P cask scaled down, using Fluent code. Based on the proposed scaling methodology and its scaling parameters, a thermal-hydraulic experiment with a half-height single assembly was carried out. The experiment was analyzed in comparison with a CFD simulation to validate the proposed CFD models in Fluent code. The results showed good agreement for the peak cladding temperature (215 °C from the experiment, 212 °C from the CFD). It is regarded that the proposed scaling methodology was reasonably validated as maintaining the similarity of the temperature gradient and the peak cladding temperature.     

R&D activities of the liquid breeder blanket in Korea

A liquid breeder blanket has been developed in parallel with the International Thermonuclear Experimental Reactor (ITER) Test Blanket Module (TBM) program in Korea. The Korea Atomic Energy Research Institute (KAERI) has developed the common fields of a solid TBM such as design tools, structural material, fabrication methods, and He cooling technology to support this concept for the ITER. Also, other fields such as a liquid breeder technology and tritium extraction have been developed from the designed liquid TBM. For design tools, system codes for safety analysis such as Multi-dimensional Analysis of Reactor Safety (MARS) and GAs Multi-component Mixture Analysis (GAMMA) were developed for He coolant and liquid breeder. For the fabrication methods, Ferritic Martensitic Steel (FMS) to FMS and Be to FMS joinings with a Hot Isostatic Pressing (HIP) were developed and verified with a high heat flux test of up to 0.5–1.0 MW/m². Moreover, three mockups were successfully fabricated and a 10-channel prototype is being fabricated to make a rectangular channel FW. For the integrity of the joining, two high heat flux test facilities were constructed, and one using an electron beam has been constructed. With the 6 MPa nitrogen loop, a basic heat transfer experiment for code validation was performed. From the verification of the components such as preheater and circulator, a 9 MPa He loop was constructed, and it supplies high temperature (500 °C) and pressure (8 MPa) He to the high heat flux test facility. For an electromagnetic (EM) pump development for circulating the liquid breeder, magnetohydrodynamic (MHD) experiment, and flow corrosion test, a PbLi breeder loop was constructed. From the performance test, the EM pump and magnet show their capability, and flow and static corrosion tests including oxide coating for corrosion protection were performed. For tritium extraction from the liquid breeder, a gas–liquid contact method was adopted and a tritium extraction chamber was constructed. For measurement of the tritium amount in the liquid breeder, permeation sensors have been developed.