The ULTRAFLOW spacer—an advanced feature of ATRIUM fuel assemblies for boiling water reactors

Critical power performance of reload fuel assemblies has a significant influence on economy in terms of fuel cycle costs and on operational flexibility of boiling water reactors. Well-known advantages in critical power performance attributed to the spacer design have been a stimulus for the development of a new spacer concept. The development was aimed at maximizing the effectiveness of phase separation in the subchannels of the fuel assemblies while minimizing the pressure drop across the spacers. Air-water tests at virtually atmospheric pressure and room temperature were used for a comparative qualitative study of the typical effects on subchannel and film flow downstream of various types of spacer. The most promising design concept proved to be the ULTRAFLOW^TM (Siemens trademark) spacer, which is an egg-crate-type spacer with swirl vanes. Critical power and pressure drop performance of the ULTRAFLOW spacer have been measured at the Karlstein test facility of Siemens. The results show that the critical power performance of this spacer is on an average 8% higher than that of the ring spacer and 16% higher than that of the egg-crate spacer without swirl vanes while its pressure drop is lower compared with the above types.     

Diagnosis of gastric cancer up to three years after negative upper gastrointestinal endoscopy

BACKGROUND AND STUDY AIMS: The degree of accuracy of gastroscopy for the detection of gastric cancer is poorly understood. The aim of this retrospective study was to determine the accuracy of gastroscopy by using cancer registry records. PATIENTS AND METHODS: Gastroscopic examinations (n = 37094) conducted between 1984 and 1989 were studied by linking them with hospital-based and population-based (Fukui Prefecture, Japan) cancer registry records between 1984 and 1992. False-negative gastroscopies that had been carried out within the three years preceding the diagnosis of gastric cancer were identified. RESULTS: The numbers of true-positive, false-positive, and false-negative examinations carried out were 659, six and 155, respectively. The sensitivity, specificity, positive predictive value, and negative predictive value were 81.0%, 100.0%, 99.1%, and 99.6%, respectively. The overall diagnostic accuracy of gastroscopy was 99.6%. There was little difference in sensitivity results between the patient groups with regard to reason for referral, type of endoscope used, experience of endoscopist, or location of gastric cancer. The percentage of tumours representing early gastric cancer, identified after false-negative gastroscopy, was lower for those situated in the cardia or gastric body than for those in the angular notch or the antrum. CONCLUSIONS: The accuracy of gastroscopy in the detection of gastric cancer is satisfactory, but false-negative results are sometimes obtained. We emphasize the importance of repeated endoscopic examination for the detection of gastric cancer.     

On the Design of a High-Performance LSI Circuit Digital Signal Processor for Communication

This paper describes the design of a highly efficient CMOS LSI circuit digital signal processor (FDSP3). To realize an operating cycle rate of 10 MHz and a throughput rate of 0.6 μs per second-order filter section, considerable care has been paid to the design of software structures and hardware circuitry. Basic program routines and some application examples are also shown. These examples illustrate the high efficiency of the developed DSP device.     

Three-dimensional gadolinium-enhanced dynamic MRI of whole liver using spectrally selected enhanced fast gradient recall sequence]

Although scribing has been used in ophthalmology for many years, the real benefits could not be realized until the entry of managed care into medicine in the United States. Everyone benefits in an office that uses scribes. The patient and the physician benefit by having a record that is much closer to being complete. The technician benefits as a result of becoming a pivotal reference for every patient encounter.     

Characterization of high- and low-molecular weight zinc-dependent acid phosphatases in bovine liver

We have purified two forms of Zn2+-dependent acid phosphatase (Zn2+-APase) from bovine liver, both of which require Zn2+ to hydrolyze the substrate p-nitrophenyl phosphate in an acidic environment. The apparent molecular weights of these two forms of Zn2+-APase were estimated to be about 100,000 and 62,000 by gel filtration, and about 44,000 and 31,000 by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate, respectively. The low-molecular weight (LMW) Zn2+-APase catalyzed the hydrolysis of myo-inositol-1-phosphate in the presence of 3 mM Mg2+ at physiological pH, but the high-molecular weight (HMW) enzyme did not. The LMW-Zn2+-APase of bovine liver was recognized by polyclonal antibodies developed against the Zn2+-APase of bovine brain, but the HMW-Zn2+-APase was not.     

Development of one pass sea water reverse osmosis module “Hollosep”

CTA hollow fiber membranes with high performance, especially high salt rejection, have been developed for one pass sea water desalination by reverse osmosis.Performances of modules have been studied relating to sea water desalination and are discussed in terms of hollow fiber membrane and module configuration.High salt rejection makes it possible to operate under severe operating conditions of high product water recovery and high salinity sea water.Operating costs are discussed with regard to product water recovery.     

Subzero Nonfreezing Hypothermia with Insect Antifreeze Protein Dramatically Improves Survival Rate of Mammalian Cells

Cells for therapeutic use are often preserved at +4 °C, and the storage period is generally limited to 2–3 days. Here, we report that the survival rate (%) of mammalian cells is improved to 10–20 days when they are preserved with a subzero supercooled solution containing the antifreeze protein (AFP), for which an ability to stabilize both supercooled water and cell membrane integrity has been postulated. We chose adherent rat insulinoma (RIN-5F) cells as the preservation target, which were immersed into −5 °C-, −2 °C-, or +4 °C-chilled “unfrozen” solution of Euro-Collins or University of Washington (UW) containing the AFP sample obtained from insect or fish. Our results show that the survival rate of the cells preserved with the solution containing insect AFP was always higher than that of the fish AFP solution. A combination of the −5 °C-supercooling and insect AFP gave the best preservation result, namely, UW solution containing insect AFP kept 53% of the cells alive, even after 20 days of preservation at −5 °C. The insect AFP locates highly organized ice-like waters on its molecular surface. Such waters may bind to semiclathrate waters constructing both embryonic ice crystals and a membrane–water interface in the supercooled solution, thereby protecting the cells from damage due to chilling.     

Fabrication of Highly Porous Alumina Prepared by Gelation Freezing Route with Antifreeze Protein

Macroporous alumina ceramic monolith was fabricated by the novel gelation freezing method with antifreeze protein (AFP). The gelation freezing route with AFP is a simple and efficient way to produce macrocellular ceramics with tailored and uniform pore architecture as well as high porosity.     

Diffusion bonding of SiC ceramics with interlayers of metallic titanium foils and PVD titanium coatings

Silicon carbide (SiC) is a candidate material for high-temperature structural aerospace applications due to its thermal and mechanical properties. Joining technologies enable the fabrication of complex shaped components needed for such applications. Various interlayers and processing conditions were used to form diffusion bonds between SiC substrates. Interlayers of titanium (Ti) foils and physically vapor deposited Ti coatings were used in the thicknesses of 10 and 20 μm with processing hold times of 1, 2, and 4 h. Polished cross sections of resulting diffusion bonds were analyzed using scanning electron microscopy (SEM) coupled with energy-dispersive spectroscopy (EDS) and using transmission electron microscopy (TEM). From the TEM analysis, selected-area diffraction patterns for Ti₃SiC₂, Ti₅Si₃C_x, and TiSi₂ were observed. Moreover, TiC and an unknown phase were present in diffusion bonds formed with metallic titanium foil. From the SEM/EDS analyses, intermediate phases of Ti₅Si₃C_x and TiC were found to be present in microcracked diffusion bonds. With the thinner Ti interlayers and/or longer processing time, microcracking was alleviated or eliminated due to the presence of the more stable and lower thermal expansive phases of Ti₃SiC₂ and TiSi₂. Detailed analysis of microstructures and the probable phases that formed in the bonded regions is presented.