Creep Properties of 9Cr and 14Cr ODS Tubes Tested by Inner Gas Pressure

Oxide-dispersion strengthened steels are promising materials for extreme service conditions including nuclear reactors core. In service conditions, nuclear fuel claddings are exposed to the fission gas pressure at temperatures about 700 °C. This paper presents novel results on ODS creep properties from a round robin of inner gas pressure creep test. A gas pressure creep test, simulating fission gas loading, was designed and achieved by four different European teams. Lifetime and specific behavior of ODS steel tube are prospected. Based on a mechanical clamping achieving gas tightness, short length tubes samples are tested by different laboratories. In situ laser measurements exhibit the radial expansion of ODS steel tubes before failure. Post-mortem, geometrical characterizations are performed to determine hoop strains at failure. A consistent creep lifetime is observed by all the teams even with slightly different testing apparatus and clamping systems. Under inner gas pressure, ODS steels exhibit a typical failure by leakage associated to a very small radial expansion. This behavior results from a brutal failure (burst) without evidence of tertiary creep stage. This failure mode of ODS cladding in creep conditions is consistently observed on all samples of the study. Inner gas pressure creep tests were compared, for the first time, by four European laboratories on ODS steel tube. This technique, simulating the fission gas pressure loading, is applied on small and mechanically clamped samples. This technique shows a remarkable consistency between the different laboratories results and demonstrates to be efficient for ODS steel cladding tube qualification. The results show a correlation between the creep properties and the microstructure.

     

Intermittent Hypoxic Therapy Inhibits Allogenic Bone-Graft Resorption by Inhibition of Osteoclastogenesis in a Mouse Model

Systemic Intermittent Hypoxic Therapy (IHT) relies on the adaptive response to hypoxic stress. We investigated allogenic bone-graft resorption in the lumbar spine in 48 mice. The mice were exposed to IHT for 1 week before surgery or 1 week after surgery and compared with controls after 1 and 4 weeks. Complete graft resorption was observed in 33–36% of the animals in the control group, but none in the preoperative IHT group. Increased bone-graft volume was demonstrated by micro-computed tomography in the preoperative IHT group after 1 week (p = 0.03) while a non-significant difference was observed after 4 weeks (p = 0.12). There were no significant differences in the postoperative IHT group. Increased concentration of immune cells was localized in the graft area, and more positive tartrate-resistant acid phosphatase (TRAP) staining was found in controls compared with IHT allogenic bone grafts. Systemic IHT resulted in a significant increase of the major osteoclast inhibitor osteoprotegerin as well as osteogenic and angiogenic regulators Tgfbr3, Fst3l, Wisp1, and Vegfd. Inflammatory cytokines and receptor activator of nuclear factor kappa-B ligand (RANKL) stimulators IL-6, IL-17a, IL-17f, and IL-23r increased after 1 and 4 weeks, and serum RANKL expression remained constant while Ccl3 and Ccl5 decreased. We conclude that the adaptive response to IHT activates numerous pathways leading to inhibition of osteoclastic activity and inhibition of allogenic bone-graft resorption.     

A rheo-optical apparatus for real time kinetic studies on shear-induced alignment of self-assembled soft matter with small sample volumes

In soft materials, self-assembled nanoscale structures can allow new functionalities but a general problem is to align such local structures aiming at monodomain overall order. In order to achieve shear alignment in a controlled manner, a novel type of rheo-optical apparatus has here been developed that allows small sample volumes and in situ monitoring of the alignment process during the shear. Both the amplitude and orientation angles of low level linear birefringence and dichroism are measured while the sample is subjected to large amplitude oscillatory shear flow. The apparatus is based on a commercial rheometer where we have constructed a flow cell that consists of two quartz teeth. The lower tooth can be set in oscillatory motion whereas the upper one is connected to the force transducers of the rheometer. A custom made cylindrical oven allows the operation of the flow cell at elevated temperatures up to 200 degrees C. Only a small sample volume is needed (from 9 to 25 mm(3)), which makes the apparatus suitable especially for studying new materials which are usually obtainable only in small quantities. Using this apparatus the flow alignment kinetics of a lamellar polystyrene-b-polyisoprene diblock copolymer is studied during shear under two different conditions which lead to parallel and perpendicular alignment of the lamellae. The open device geometry allows even combined optical/x-ray in situ characterization of the alignment process by combining small-angle x-ray scattering using concepts shown by Polushkin et al. [Macromolecules 36, 1421 (2003)].     

Yearly average performance of the principal solar collector types

The results of hour-by-hour simulations for 26 meteorological stations are used to derive universal correlations for the yearly total energy that can be delivered by the principal solar collector types: flat plate, evacuated tubes, CPC, collectors that track about one axis, collectors that track about two axes, and central receiver.The correlations are polynomials of first and second order in yearly average insolation, latitute, and threshold (= ratio of heat loss and optical efficiency). With these correlations the yearly collectible energy can be found by reading a single graph and multiplying the coordinates by the collector parameters. This simple method reproduces the results of hour-by-hour computer calculations with an accuracy (rms error) of 2 per cent for flat plates and 2–4 per cent for concentrators.This method can be applied to any system where the collectors operate year-round in such a way that no collected energy is discarded. This includes photovoltaic systems; solar-augmented industrial process heat systems; and solar thermal power systems. In addition, the method is recommended for rating collectors of different types or different manufacturers on the basis of yearly average performance. The method is also useful for evaluating the effects of collector degradation, the benefits of collector cleaning, and the gains from collector improvements (due to enhanced optical efficiency or decreased heat loss per absorber surface). For most of these applications, the method is accurate enough to replace a system simulation.     

Surface‐modified carbon black derived from used car tires as alternative,reusable, and regenerable catalysts for H2 release studies from sodium borohydride methanolysis

Carbon black (CB) obtained from used car tire rubbers were treated with concentrated sulfuric and nitric acids. The oxidized CB (CB‐COO‐Na⁺) is subsequently modified with epichlorohydrin (ECH) and amines including polyethylene imine (PEI). These modified CBs such as CB‐PEI are used as metal‐free catalysts in methanolysis of sodium borohydride (NaBH₄) to produce hydrogen. The hydrogen generation rate (HGR) of 3089 ± 44.69 mL.min^‐1.g^‐1 is accomplished at room temperature with CB‐PEI‐hydrochloric acid (HCl) catalyst. The resulting activation energy of 34.7 kJ/mol for the temperature range of ?20°C to +30°C compares favorably to most of alternative catalysts reported in literature while reaction catalyzing capabilities of CB‐PEI‐HCl particles extend to the subzero temperature range (?20°C‐0°C). The reuse and regeneration studies conducted for the CB‐PEI‐HCl catalyst showed that these catalysts do provide complete conversion at every use up to five consecutive runs and retain 50 ± 2.5% of the original hydrogen generation rate at the fifth consecutive reuse. The CBs‐based catalysts are fully regenerated with HCl treatment.     

Monovalent cation transporters at the plasma membrane in yeasts

Maintenance of proper intracellular concentrations of monovalent cations, mainly sodium and potassium, is a requirement for survival of any cell. In the budding yeast Saccharomyces cerevisiae, monovalent cation homeostasis is determined by the active extrusion of protons through the Pma1 H⁺-ATPase (reviewed in another chapter of this issue), the influx and efflux of these cations through the plasma membrane transporters (reviewed in this chapter), and the sequestration of toxic cations into the vacuoles. Here, we will describe the structure, function, and regulation of the plasma membrane transporters Trk1, Trk2, Tok1, Nha1, and Ena1, which play a key role in maintaining physiological intracellular concentrations of Na⁺, K⁺, and H⁺, both under normal growth conditions and in response to stress.     

Combined innovation and export strategies of KIBS in different regional settings

This paper examines how KIBS establishments combine innovation and exports, and which factors are associated with these combinations. In particular, we hypothesize that KIBS establishments which both export and innovate will be over-represented in metropolitan regions, and under-represented in peripheral regions. Our analysis draws upon a sample of 429 innovative KIBS establishments in the province of Quebec (Canada). We show that strategies differ across space (but not as expected – metropolitan and peripheral strategies are similar), that T-KIBS’ strategies are associated with non-market information sources, and that P-KIBS' strategies are associated with information purchasing. P-KIBS’ and T-KIBS’ strategies vary with the performance of in-house R&D. Taken together, these results suggest that whereas KIBS’ choice of export and innovation strategies do not reflect their ‘hard’ or ‘soft’ nature, the factors associated with this choice do. The similarity between metropolitan and peripheral regions reflects the fact that Quebec’s resource-based peripheral economy is international and innovative.     

有效的过程控制改善湿部稳定性

对纸机湿部化学系统进行管理就要对影响该系统的因素进行控制，文章通过列举实例讨论了对留着率和电荷的控制。     

Influence of charged tail groups of self-assembled monolayers on electrodeposition of polyaniline

Self-assembled monolayers (SAMs) of thiols with three different tail groups, −COOH, −SO₃Na, and −NH₂, were used to modify the Au substrates for electrodepositing polyaniline (PANI). Electrochemical quartz crystal microbalance (EQCM) results indicated a slower rate of deposition of PANI on a SAM surface consisting of positively charged amine groups compared to polymerization on bare gold and on a SAM of carboxyl acid groups. The properties of the SAM layers are dependent on the pH value of the solutions, and are effective only at very low pH values (pH < 2). A layer of the positively charged amino groups in acidic solution acted as a barrier for electron transfer in electro-oxidation of aniline monomer. The positively charged SAM of amine groups also increased repulsion between the coupled aniline species and the electrode surface and in this way hindered electrodeposition. Modification of the surface with pre-patterned SAMs have been demonstrated to be a convenient and practical way to fabricate selectively deposited thin films of polyaniline.     

Gaucher Disease Diagnosis Using Lyso-Gb1 on Dry Blood Spot Samples: Time to Change the Paradigm?

For years, the gold standard for diagnosing Gaucher disease (GD) has been detecting reduced β-glucocerebrosidase (GCase) activity in peripheral blood cells combined with GBA1 mutation analysis. The use of dried blood spot (DBS) specimens offers many advantages, including easy collection, the need for a small amount of blood, and simpler transportation. However, DBS has limitations for measuring GCase activity. In this paper, we recount our cross-sectional study and publish seven years of experience using DBS samples and levels of the deacylated form of glucocerebroside, glucosylsphingosine (lyso-Gb1), for GD diagnosis. Of 444 screened subjects, 99 (22.3%) were diagnosed with GD at a median (range) age of 21 (1–78) years. Lyso-Gb levels for genetically confirmed GD patients vs. subjects negative to GD diagnosis were 252 (9–1340) ng/mL and 5.4 (1.5–16) ng/mL, respectively. Patients diagnosed with GD1 and mild GBA1 variants had lower median (range) lyso-Gb1, 194 (9–1050), compared to GD1 and severe GBA1 variants, 447 (38–1340) ng/mL, and neuronopathic GD, 325 (116–1270) ng/mL (p = 0.001). Subjects with heterozygous GBA1 variants (carrier) had higher lyso-Gb1 levels, 5.8 (2.5–15.3) ng/mL, compared to wild-type GBA1, 4.9 (1.5–16), ng/mL (p = 0.001). Lyso-Gb1 levels, median (range), were 5 (2.7–10.7) in heterozygous GBA1 carriers with Parkinson’s disease (PD), similar to lyso-Gb1 levels in subjects without PD. We call for a paradigm change for the diagnosis of GD based on lyso-Gb1 measurements and confirmatory GBA1 mutation analyses in DBS. Lyso-Gb1 levels could not be used to differentiate between heterozygous GBA1 carriers and wild type.