Safety design of Pb–Bi-cooled direct contact boiling water fast reactor (PBWFR)

In Pb–Bi-cooled direct contact boiling water small fast reactor (PBWFR), steam is generated by direct contact of feedwater with primary Pb–Bi coolant above the core, and Pb–Bi coolant is circulated by steam lift pump in chimneys. Safety design has been developed to show safety features of PBWFR. Negative void reactivity is inserted even if whole of the core and upper plenum are voided hypothetically by steam intrusion from above. The control rod ejection due to coolant pressure is prevented using in-vessel type control rod driving mechanism. At coolant leak from reactor vessel and feedwater pipes, Pb–Bi coolant level in the reactor vessel required for decay heat removal is kept using closed guard vessel. Dual pipes for feedwater are employed to avoid leak of water. Although there is no concern of loss of flow accident due to primary pump trip, feedwater pump trip initiates loss of coolant flow (LOF). Injection of high pressure water slows down the flow coast down of feedwater at the LOF event. The unprotected loss of flow and heat sink (ATWS) has been evaluated, which shows that the fuel temperatures are kept lower than the safety limits.     

An Enzymatic Assay Method for Bacterial Alpha-amylase Using a Glucose Determination-kit and Maltohexaose as the Substrate

Using maltohexaose G₆ as a substrate, a convenient analytical method for amylase-catalyzed hydrolytic reaction was developed by application of an enzymatic assay-kit (glucose oxidase-peroxidase) to measurement of glucose, produced on the reaction: G₆→G₅ + G. The initial velocity was confirmed to be proportional to the initial concentration of amylase, examined, ∼ 100 μm. The new method was found in a good correlation with the Nelson and Somogyi method. Rate assay was also examined: The initial velocity is proportional to the enzyme concentration, ∼ 30 μm. Hence, this enzymatic assay method is recognized to be convenient and useful for the measurement of α-amylase.     

High-throughput immunophenotyping by surface plasmon resonance imaging

Cell binding assays on antibody arrays permit the rapid immunophenotyping of living cells. The throughput of the analysis, however, is still limited due to our inability to perform parallel and quantitative detection of cells captured on the array. To address this limitation, we employed here an imaging technique based on surface plasmon resonance (SPR). SPR has been frequently used to monitor capture of proteins on antibody microarrays, while few cases were reported for capture of cells. Antibody arrays were prepared through the photopatterning of an alkanethiol monolayer on a gold-evaporated glass plate and the subsequent immobilization of various antibodies onto 4-9 separate spots created by photopatterning. A glass slip was mounted onto the array with a thin spacer to construct a parallel-plate chamber. Leukemia cells were injected into the chamber to conduct a binding assay, while refractive index changes at the vicinity of the array surface were monitored by SPR imaging. We observed that SPR signals were intensified on specific antibody spots but not on nonspecific spots. Confocal laser scanning microscopy revealed that the observed SPR signals were attributed to cell deformations caused by multivalent interactions with immobilized antibody, which effectively elevated the refractive index of a medium phase within an evanescent field. This effect could be suitably utilized to monitor quantitatively cell binding to multiple spots from a heterogeneous cell population.     

Synthesis and characterization of propylene‐α‐olefin random copolymers with isotactic propylene sequence. II. Propylene–hexene‐1 random copolymers

A series of novel hexene‐1–propylene random copolymers with isotactic sequence of propylene was synthesized with a MgCl₂‐supported Cr(acac)₃ catalyst. The molecular weight distribution of copolymers and homopolymers was considerably narrower than that of typical polyolefins produced by heterogeneous Ziegler–Natta catalysts. The crystallizability of the copolymers having a propylene‐unit content of more than 50 mol % drastically decreased with decreasing propylene‐unit content, and the copolymers with a propylene content of less than 50 mol % were completely amorphous. In the present novel type of random copolymers with crystallizable and noncrystallizable units, a single glass transition was observed between pure polypropylene and polyhexene‐1, and a major component was found to govern the final morphology and the mechanical characteristics. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2949–2954, 2004     

Synthesis of polyamides from sugar derived d-glucaric acid and xylylenediamines

d -Glucaric acid (GA) is the one of aldaric acids and is an important bio-based building block for polymers. In this study, poly(m-xylylene-acetyl glucaramide) and poly(p-xylylene-acetyl glucaramide) were synthesized from GA acetate and two kind of aromatic diamines by solution polymerization. The chemical structures of the polyamides were analyzed by nuclear magnetic resonance spectroscopy. The weight-average molecular weights ranged from 3.3 × 10³ to 1.15 × 10⁴ with a polydispersity of 1.6–1.9, depending on monomer ratio or monomer concentration in solution. The 10% decomposition temperature of the polymers was about 210 °C. Differential scanning calorimetry revealed that the polyamides exhibited no peaks attributed to crystallization or melting point, which indicated that the polyamides were amorphous. No crystalline pattern was observed in the X-ray diffractograms, supporting this result. Polarized optical microscopy observation revealed that the polyamides exhibited melting-like behavior at above 150 °C, which was attributed to glass-transition behavior. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47255.     

Performances of metal fluoride added carbon anodes with pre-electrolysis for electrolytic synthesis of NF3

Metal fluoride added carbon anodes treated by pre-electrolysis were investigated for electrolytic production of nitrogen trifluoride (NF₃) in molten NH₄F·KF·4HF at 100 °C. The conditions for pre-electrolysis were first optimized using a graphite sheet anode as a model anode. The formation of fluorine-graphite intercalation compounds (fluorine-GICs) with semi-covalent C–F bonds, (C_xF)_n, on the MgF₂ and CaF₂ added carbon anode surface was accelerated by pre-electrolysis at potentials less than 4.0 V. Critical current densities (CCD) on the MgF₂ added carbon anodes pre-electrolyzed under various conditions were determined, and the highest CCD was 290 mA cm⁻² obtained for that pre-electrolyzed at 3.5 V for 500 C cm⁻². This anode was successfully used in the electrolysis at 100 mA cm⁻² for 290 h and the maximum NF₃ current efficiency was 55%. From these results, it was concluded that the metal fluoride added carbon anode treated by pre-electrolysis has a high potential for electrolytic production of NF₃ at higher current density.     

Germanium recovery using polyphenol microspheres prepared by horseradish peroxidase reaction

BACKGROUND: The formation of polyphenol microspheres by the polymerization of 3‐methylcatechol was performed in a methanol/phosphate buffer solution using horseradish peroxidase (HRP), without the use of a surfactant or a water/oil interface, to be used for germanium recovery. RESULTS: The polyphenol microspheres were of diameter 1 mm. The functional group density of phenol group in the polymer was approximately 15 mol kg^?1 determined by the Folin‐Denis method. In batchwise experiments, the amount of germanium adsorbed was 0.23 mol kg^?1. CONCLUSION: Because germanium is a rare metal, a system for its recovery is required. Using the proposed system, continuous recovery of germanium can be achieved using multilayered microspheres. Copyright © 2011 Society of Chemical Industry     

A New Slip Frequncy Detector of an Induction Motor Utilizing Rotor Slot Harmonics

A method to detect slip frequency from rotor slot harmonics of a three-phase squirrel-cage induction motor is proposed. The rotor slot harmonic voltage Is obtained by summing the three phase voltages, and after being sampled with a multiple of the stator frequency, it is changed into slip frequency waves, from which a voltage proportional to the slip frequency is obtained. Sophisticated sampling techniques allow elimination of the third harmonic voltage induced in the sum of the three-phase voltages and also allow reduction of time constant of the slip frequency detector. Expenmental results show that the slip frequency detector has a good linearity in the range of slip frequency of about -50 to +30 percent of the stator frequency.     

Adhesion between polymer surface modified by graft polymerization and tissue during surgery using an ultrasonically activated scalpel device

In the field of surgery, achieving adhesion between a polymer implant and tissue poses a challenge considering that suturing is not appropriate for the stability of such implants. An ultrasonically activated scalpel that generates heat by mechanical vibration and promotes adhesion between a polymer implant and native tissue by pressing the two materials together has very good potential for application in the field. To determine the type of polymer that is suitable for the purpose, we investigated polyethylene (PE) and polystyrene (PS) films, the surfaces of which were activated by corona discharge. Graft polymerization was then performed on the corona‐treated surfaces to vary their properties. The corona‐treated PE and PS films grafted with poly(acrylic acid), poly(methacrylic acid), poly(vinyl benzylacrylic acid), and poly(hydroxylethyl acrylate), respectively, adhered to the tissue when the ultrasonically activated scalpel was applied. The heat generated by the mechanical vibration and the applied pressure enabled the carboxyl or hydroxyl groups to bond with the proteins in the extracellular matrix. We therefore concluded that it was possible to integrate this technique in the development of new types of polymer devices that could be stably implanted in a living body. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40885.