Conversion kinetics of container glass batch melting

Understanding the batch-to-glass conversion process is fundamental to optimizing the performance of glass-melting furnaces and ensuring that furnace modeling can correctly predict the observed outcome when batch materials or furnace conditions change. To investigate the kinetics of silica dissolution, gas evolution, and primary foam formation and collapse, we performed X-ray diffraction, thermal gravimetry, feed expansion tests, and evolved gas analysis of batch samples heated at several constant heating rates. We found that gas evolving reactions, foaming, and silica dissolution depend on the thermal history of the batch in a similar manner: the kinetic parameters of each process were linear functions of the square root of the heating rate. This kinetic similarity reflects the stronger-than-expected interdependence of these processes. On the basis of our results, we suggest that changes in furnace operating conditions, such as firing or boosting, influence the melting rate less than what one would expect without consideration of batch conversion kinetics.     

Investigation of ring-opening polymerization of 5-[2-{2-(2-methoxyethoxy)ethoxy}-ethoxymethyl]-5-methyl-1,3-dioxa-2-one by organometallic catalysts

To develop new polymer-based materials, the design of aliphatic carbonate has received attention and become a well-known cyclic monomer. In view of carbonate ring polymer scope, poly(trimethylene carbonate) (PTMC) has been continuously developed for further applications due to its unique degradability. PTMC bearing oligo ethylene glycol units, PTMCM-MOE3OM, were typically prepared via ring-opening polymerization (ROP) using amidine-based catalysts such as 1,8-diazabicyclo[5.4.0] undec-7-ene (DBU) and benzyl alcohol (BnOH) as an initiator. To improve the polymer molecular weight or other properties, several know-how synthetic catalysts based on organometallic complexes are under consideration as potential catalysts. With the existence of diverse classes of metallic complexes, the inorganic complexes were investigated for their catalytic activity based on tris(dimethylsilyl)amido chelating, bis(phenolate) chelating, and macrocyclic tetradentate (NNNN)-type cyclen chelating with a metal-core of tin (II), scandium (III), lutetium (III), and zinc (II). In this study, we found that involving a Zn(II) dimethylcyclen/alkoxide ligand and Mg complexes could accelerate the reaction and finish the polymerization under ambient conditions within 2 hr. Molecular weight reached 11,000 g/mol (40%) and 8,100 g/mol (> 96%). Subsequently, we concluded that Zn and Mg complexes were high reactivity for initiating the ROP of TMCM-MOE3OM upon steadily degree of polymerization.     

Nanoconfined (Bio)Catalysts as Efficient Glucose‐Responsive Nanoreactors

Herein, the design, synthesis, and characterization of bifunctional hybrid nanoreactors used for concurrent one‐pot chemoenzymatic reactions are shown. In the design, the enzyme, glucose oxidase, is wrapped with a peroxidase‐mimetic catalytic polymer. Hemin, the organic catalyst, is linked to the flexible polymeric scaffold through coordination to the imidazole groups that hang out the network. This spatial arrangement, which works as a metabolic channel, is optimized for cooperative chemoenzymatic reactions in which the enzyme catalyzes first. A deep characterization of the integrated nanoreactors demonstrates that the confinement of two distinct catalytic sites in the nanospace is very effective in one‐pot reactions. Moreover, besides its role as scaffold material, the polymeric mantel protects both the biocatalyst and the chemical catalyst from degradation and inactivation in the presence of organic solvents. Furthermore, the polymeric environment of the nanoreactors can be tailored in order to trigger the assembly of those into highly active heterogeneous hybrid catalysts. Finally, the new nanoreactors are applied to the efficient degradation of organic aromatic compounds using glucose as the only fuel.     

Effect of addition of corrosion inhibitors on corrosion behaviors of PCV material under diluted artificial seawater environment

ABSTRACT

Fukushima Daiichi nuclear power plants (1F) were damaged by unprecedented severe accident in the great east Japan earthquake, and seawater and freshwater had been injected as an emergency countermeasure for the core cooling. Although, the primary containment vessel (PCV) was not supposed to be exposed to diluted seawater, the PCV will be exposed to diluted seawater environment until fuel debris removal is completed. Therefore, it is necessary to establish a countermeasure of corrosion for the PCVs made of carbon steel. In this study, the effect of the addition of corrosion inhibitor, which is one of the corrosion countermeasures, was investigated by two types of corrosion tests. As a result of the immersion corrosion test, it was found that any of the three kinds of corrosion inhibitor could suppress corrosion of carbon steel. In addition, as a result of the inhibitor interim addition test, it was found that corrosion of carbon steel covered with corrosion products could be suppressed by optimizing the additive amount of corrosion inhibitor in the cooling water.     

Surface Analysis of Cr2O3‐, CoO‐, and Al2O3‐Doped Iron–Phosphate Glasses at High Temperature

Surface structures of iron–phosphate glasses were examined using X‐ray photoelectron spectroscopy (XPS). Cr₂O₃, CoO, and Al₂O₃ were introduced to the glass by the replacement of a part of Fe₂O₃, and the simulated fission products are also added. The obtained glasses showed high chemical durabilities by MCC‐1 test. In situ high‐temperature and room‐temperature XPS measurements were conducted on the polished sample surfaces and also those after 1‐week chemical durability test. Unique trends were observed in XPS spectra on heating and after the chemical durability test, respectively. Nature of the glass surface of iron–phosphate glasses was explained from the point of view of surface energy, and the origin of high chemical durability and the effect of chromium ions were discussed based on the changes on surface composition and valence states of transition‐metal ions.     

Application of the Antibody-Inducing Activity of Glycosphingolipids to Human Diseases

Glycosphingolipids (GSLs) are composed of a mono-, di-, or oligosaccharide and a ceramide and function as constituents of cell membranes. Various molecular species of GSLs have been identified in mammalian cells due to differences in the structures of oligosaccharides. The oligosaccharide structure can vary depending on cell lineage, differentiation stage, and pathology; this property can be used as a cell identification marker. Furthermore, GSLs are involved in various aspects of the immune response, such as cytokine production, immune signaling, migration of immune cells, and antibody production. GSLs containing certain structures exhibit strong immunogenicity in immunized animals and promote the production of anti-GSL antibodies. By exploiting this property, it is possible to generate antibodies that recognize the fine oligosaccharide structure of specific GSLs or glycoproteins. In our study using artificially synthesized GSLs (artGSLs), we found that several structural features are correlated with the antibody-inducing activity of GSLs. Based on these findings, we designed artGSLs that efficiently induce the production of antibodies accompanied by class switching and developed several antibodies that recognize not only certain glycan structures of GSLs but also those of glycoproteins. This review comprehensively introduces the immune activities of GSLs and their application as pharmaceuticals.     

GPU Acceleration for FEM-Based Structural Analysis

Graphic Processing Units (GPUs) have greatly exceeded their initial role of graphics accelerators and have taken a new role of co-processors for computation—heavy tasks. Both hardware and software ecosystems have now matured, with fully IEEE compliant double precision and memory correction being supported and a rich set of software tools and libraries being available. This in turn has lead to their increased adoption in a growing number of fields, both in academia and, more recently, in industry. In this review we investigate the adoption of GPUs as accelerators in the field of Finite Element Structural Analysis, a design tool that is now essential in many branches of engineering. We survey the work that has been done in accelerating the most time consuming steps of the analysis, indicate the speedup that has been achieved and, where available, highlight software libraries and packages that will enable the reader to take advantage of such acceleration. Overall, we try to draw a high level picture of where the state of the art is currently at.     

Relation of crack-induced current shunting to transport current and n-value in DyBCO-coated superconductor

Transport current and n-value of DyBCO-coated conductor pulled in tension were measured experimentally and their relation to crack-induced current shunting was analyzed with the partial crack-current shunting model. The following features were revealed. The shunting current increases with increasing transport current and with increasing crack size. At low voltage where shunting current is low, the transport current of cracked sample normalized with respect to the transport current in non-cracked state is described with the modified ratio of non-cracked area to overall cross-sectional area of superconducting layer. At high voltage where the shunting current is high, the normalized transport current becomes higher than the modified ratio of non-cracked area. The increase in shunting current with transport current (and voltage) leads to a decrease in n-value at high current (voltage). This phenomenon is enhanced by crack extension.     

Packed Powder as Superleak for Spin Pump Experiments in Superfluid 3He A1

Experimental exploration of highly spin-polarized states of liquid ³He by applying external magnetic field is limited by the availability of static magnetic field. In the “ferromagnetic” superfluid A₁ phase of liquid ³He there is an alternate method for boosting spin-polarization by the process of spin pumping without requiring such high magnetic field. The spin pumping in the A₁ phase takes advantage of a superleak (SL) acting simultaneously as a filter for both entropy and spin. The spin pump technique that uses the SL-spin filter and a mechanical actuator enables us to directly boost polarization of ³He. The amount of enhancement of spin polarization has been limited so far. We are now developing a new type of SL filter made of packed aluminum oxide powder (referred as PAP-SL), in order to achieve greater enhancement of spin polarization. Several kinds of the PAP-SL filter were constructed by pressing aluminum oxide powders into a cylinder holder. The packed structures were carefully characterized by a flow-rate-measurement, X-ray tomography, and mercury intrusion porosimetry. The preliminary result shows that the PAP-SL works as SL filter for the superfluid ³He.