PbBi-cooled direct contact boiling water small reactor

A design concept of PbBi cooled direct contact boiling water small fast reactor (PBWFR) has been formulated with some design parameters identified. Water is injected into hot PbBi above the core, and direct contact boiling takes place in chimneys. Boiling bubbles rise due to buoyancy effects, which works as a lift pump for PbBi circulation. The generated steam passes through separators and dryers for the removal of PbBi droplets, and then flows into turbines for the generation of electricity. The system pressure of 7 MPa is as the same as that of the conventional boiling water reactors (BWRs). The outlet steam is superheated by 10°C to avoid the accumulation of condensate on a PbBi free surface in the reactor vessel. The control rods are inserted from above, which is different from the original concept. This insertion was chosen since the seal of steam at the top of the reactor vessel is technically much easier than the seal of PbBi at the bottom of the reactor vessel. The electric power of 150 MWe may be the maximum which is practically possible as a small reactor with economic competitiveness to conventional LWRs. A two-region core is designed. A decrease in reactivity was estimated to be 1.5%dk/kk′ for 15 years. A fuel assembly has 271 fuel rods with 12.0 mm in diameter and 15.9 mm in pitch in a hexagonal wrapper tube. The design limit of cladding temperature is specified to be 650°C for compatibility of cladding material with PbBi. As a result, the PbBi core outlet temperature becomes 460°C. The PbBi temperature rise in the core is 150°C. The conditions of the secondary coolant steam are as the same as those of conventional BWRs with thermal efficiency of 33%. The core is designed to have the breeding ratio of 1.1 and the refueling interval of 15 years as a reactor with a long-life core. Direct heat exchangers (DHX), reactor vessel air cooling systems (RVACS) and guard vessel are designed.     

Structure and properties of syndiotacticity‐rich poly(vinyl alcohol) prepared through saponification of drawn poly(vinyl trifluoroacetate) with gaseous ammonia

The structure and properties of syndiotacticity‐rich poly(vinyl alcohol) (s‐PVA) prepared through the saponification of drawn poly(vinyl trifluoroacetate) (PVTFAc) with gaseous ammonia were studied. The PVTFAc samples with s‐diad % of 59 and 64 were used. The s‐PVAs had low densities and showed X‐ray diagrams similar to the fiber diagram of PVA with indistinct 100, 101, 101¯, and 200 plane reflections and without the plane reflections seen at the equator of a typical fiber diagram, such as 001, 201, and 002. The s‐PVAs had melting points comparable to those of saponified and heat‐drawn samples, indicating a PVA with the typical fiber structure as seen in the X‐ray diagram of a sample. The intensity of the 916 cm⁻¹ band in the infrared spectrum related to syndiotactic diads decreased with drawing, suggesting an increase in the crystallinity. Crystals with more defects are thought to be produced in saponification. The s‐PVA films drawn 16 times and saponified had a Young's modulus and strength at break of 22 and 1.5 GPa for the sample from S‐59 and 14 and 1.2 GPa for the sample from S‐64, respectively. The crystallization‐sensitive band of 1145 cm⁻¹ in the infrared spectra of the saponified samples was weak. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 467–474, 2001     

Effect of cholestyramine on bile acid metabolism in conventional rats

Effects of cholestyramine on biliary secretion of cholesterol, phospholipids and bile acids and fecal excretion of sterols and bile acids were examined in Wistar male rats. Six rats were fed a basal diet, and the other six were fed a basal diet supplemented with 5% cholestyramine for eight days. Bile flow and biliary secretion of bile acids and phospholipids (per hour per rat) decreased with cholestyramine treatment, while biliary cholesterol secretion (per hour per rat) remained unchanged. In the biliary bile acid composition, a marked increase of chenodeoxycholic acid with a concomitant decrease of β-muricholic acid was observed in cholestyramine-treated rats. Fecal excretion of total sterols and bile acids increased about three-and four-fold, respectively, after cholestyramine treatment. The increase of fecal bile acids derived from cholic acid was more predominant than that derived from chenodeoxylcholic acid, resulting in an increase of the cholic acid group/chenodeoxycholic acid group ratio.     

A 0.5 V single power supply operated high-speed boosted andoffset-grounded data storage (BOGS) SRAM cell architecture

This paper proposes a 0.5 V/100 MHz/sub-5 mW-operated 1-Mbit SRAM cell architecture which uses a boosted and offset-grounded data storage (BOGS) scheme. The key target of BOGS is to minimize the charge amount supplied from the embedded charge pump circuits, which are required to boost the effective gate to source voltage (V₀=V_GS-V_T) up to 0.8 V necessary to achieve 100 MHz operation even at 0.5 V single power supply. Thus, the key low-power strategy of BOGS is “putting the right (higher efficiency) boosted power-supply from charge pump circuit into the right position (less power consumed transistor) in a SRAM cell.” This paper is focused on why BOGS can realize a greater savings of the charge amount supplied from the boosted power-line and can reduce the power dissipation to ⩽1/30.4 and ⩽1/3.9 compared to the previously reported negative source-line drive (NSD) scheme and negative word-line drive (NWD) scheme, respectively, while achieving a 0.5 V/100 MHz operation     

Microprocessor-Based Stabilizing Control Equipment for Survival of Isolated Mid-City Power System

This paper describes the recently developed microprocessor-based stabilizing control equipment for survival of isolated mid-city power system having heavy load and large shunt capacitance (Underground cables) of TOKYO ELECTRIC POWER COMPANY (TEPCO). The active power balance and voltage stabilizing control scheme is realized by high-speed control of the 66KV load feeders, shunt reactors, shunt capacitors and 275KV & 154KV underground transmission cables dispersed in the power system.     

Development of stone tool use by wild chimpanzees (Pan troglodytes).

At the age of 3.5 years, wild chimpanzees at Bossou, Guinea, begin to use hammer and anvil stones to crack oil-palm nuts to get the kernels. To clarify the developmental processes, the authors did a field experiment in which stones and oil-palm nuts were provided. Infant chimpanzees' stone–nut manipulation was observed and video recorded. Data were collected from 3 infants younger than 4 years old from 1992 to 1995. The authors analyzed 692 episodes of infants' stone–nut manipulation and 150 episodes of infants' observation of nut cracking performed by adults. Infants observed other chimpanzees' nut cracking and got the kernels from them. The stone–nut manipulation developed from a single action on a single object to multiple actions on multiple objects. Although infant chimpanzees at the age of 2.5 years already acquired basic actions necessary for nut cracking, they did not combine the actions in an appropriate sequence to perform actual nut cracking. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An implementation of a CMA adaptive array for high speed GMSKtransmission in mobile communications

The hardware implementation of an adaptive array as a technique for compensating multipath fading in mobile communications is described. The number of the antenna elements is four. The target communication system is modulated by 256 kbps Gaussian-filtered minimum shift keying (MSK) and has a time-division multiplexing (TDM) architecture with 24 time slots. Based on the digital beamforming concept, all of the signals and the array weights are digital-signal processed. The constant modulus algorithm (CMA) is employed for weight optimizing. In an additive white Gaussian noise channel, this system has 5.6-dB gain in an energy-per-bit-to-noise-density ratio at a bit error rate (BER) of 1.0×10^-3, compared with a single antenna system. The result of the basic field test shows that the gain at a BER of 1.0×10^-3 reaches 22.3 dB in a nonselective, slow Rayleigh fading channel given a 5 Hz maximum Doppler shift     

A practical design procedure for circularly polarized printed arrays using high frequency CAE

A practical design procedure for a circularly polarized printed array antenna composed of strip dipoles and slots (CP-PASS) is presented. CP-PASS is a kind of series-fed array, and the equivalent circuit model of CP-PASS is simplified to be suitable for a computer-aided design (CAD) package. Some experimental results of a new strip element excited by a stripline and a 9-element set CP-PASS are also presented.     

Gold-nanoparticle-assisted oligonucleotide immobilisation for improved DNA detection

Colloidal gold nanoparticles are investigated as a potential scaffold for the assisted immobilisation of probe oligonucleotides on silicon surfaces. A preliminary study is devoted to the examination of the immobilisation of DNA-modified gold nanoparticles as a function of time, concentration, salt and pH. The DNA-modified nanoparticles self-assembled onto solid surfaces in a three-dimensional self-assembled architecture. The functionalised surfaces are evaluated in diagnostic assays, where their potential to improve the efficiency of the hybridisation reaction is tested. The system utilising DNA-modified nanoparticles produced an enhancement in the hybridisation efficiency and the sensitivity limit by a factor 10 to 100 as compared to a conventional DNA immobilisation system on a planar surface.