Electrochemical measurement to examine influence of ions,DO, and pH on corrosion of early-generation conduits

ABSTRACT

In order to effectively implement measures against the adverse effects of large earthquakes on telecommunication conduits, it is important to elucidate which conduit is vulnerable. Telecommunication conduits consist of pipe bodies and joints, and as is well known the joints are weaker than the bodies against seismic loading. Hence, the seismic performance of the conduits depends on the performance of the joints. To maintain conduits properly, the corrosion rate of conduits' joint in the field must be determined. Several sites were selected and investigated for the amount of stagnant water in manholes. Next, the stagnant water test specimens were collected and observed for the extent of corrosion inside via a pipe camera, and subsequently analysed collected water test specimens. Moreover, the solution resistances and polarisation resistances using the AC impedance method and carbon steel coupons were measured. The experiments revealed differences between the measured values recorded at the different sites. It was also found that some data were related to corrosion on the inside of the conduits.

This paper is part of a supplementary issue from the 17th Asia-Pacific Corrosion Control Conference (APCCC-17).     

Iodine Excess as an Environmental Risk Factor for Autoimmune Thyroid Disease

The global effort to prevent iodine deficiency disorders through iodine supplementation, such as universal salt iodization, has achieved impressive progress during the last few decades. However, iodine excess, due to extensive environmental iodine exposure in addition to poor monitoring, is currently a more frequent occurrence than iodine deficiency. Iodine excess is a precipitating environmental factor in the development of autoimmune thyroid disease. Excessive amounts of iodide have been linked to the development of autoimmune thyroiditis in humans and animals, while intrathyroidal depletion of iodine prevents disease in animal strains susceptible to severe thyroiditis. Although the mechanisms by which iodide induces thyroiditis are still unclear, several mechanisms have been proposed: (1) excess iodine induces the production of cytokines and chemokines that can recruit immunocompetent cells to the thyroid; (2) processing excess iodine in thyroid epithelial cells may result in elevated levels of oxidative stress, leading to harmful lipid oxidation and thyroid tissue injuries; and (3) iodine incorporation in the protein chain of thyroglobulin may augment the antigenicity of this molecule. This review will summarize the current knowledge regarding excess iodide as an environmental toxicant and relate it to the development of autoimmune thyroid disease.     

Chemistry,Properties, and in Vitro and in Vivo Applications of 2′‐O‐Methoxyethyl‐4′‐thioRNA,a Novel Hybrid Type of Chemically Modified RNA

We report the synthesis, properties, and in vitro and in vivo applications of 2′‐O‐methoxyethyl‐4′‐thioRNA (MOE‐SRNA), a novel type of hybrid chemically modified RNA. In its hybridization with complementary RNA, MOE‐SRNA showed a moderate improvement of T_m value (+3.4 °C relative to an RNA:RNA duplex). However, the results of a comprehensive comparison of the nuclease stability of MOE‐SRNA relative to 2′‐O‐methoxyethylRNA (MOERNA), 2′‐O‐methyl‐4′‐thioRNA (Me‐SRNA), 2′‐O‐methylRNA (MeRNA), 4′‐thioRNA (SRNA), and natural RNA revealed that MOE‐SRNA had the highest stability (t_1/2>48 h in human plasma). Because of the favorable properties of MOE‐SRNA, we evaluated its in vitro and in vivo potencies as an anti‐microRNA oligonucleotide against miR‐21. Although the in vitro potency of MOE‐SRNA was moderate, its in vivo potency was significant for the suppression of tumor growth (similar to that of MOERNA).     

Evaluation method of dam behavior during construction and reservoir filling and application to real dams

In this paper we analyzed a real fill-type dam, named the Minami-Aiki Dam, to verify a numerical consolidation method with an elastoplastic model for unsaturated soils. The validities were conducted by comparing the analyzed and measured values during construction and impounding. The settlements calculated showed good agreement to those observed. Though the changing patterns of the measured and calculated pore water pressures were similar, the amounts of pore water pressures induced by the self-weights of embankment and the dissipation speeds were different. The earth pressures measured at the bottom of the core zone showed good agreement with those calculated. This method is valid for estimating behavior of fill-type dams during construction and impounding.     

Computational study of forced convective heat transfer in structured packed beds with spherical or ellipsoidal particles

Randomly packed bed reactors are widely used in chemical process industries, because of their low cost and ease of use compared to other packing methods. However, the pressure drops in such packed beds are usually much higher than those in other packed beds, and the overall heat transfer performances may be greatly lowered. In order to reduce the pressure drops and improve the overall heat transfer performances of packed beds, structured packed beds are considered to be promising choices. In this paper, the flow and heat transfer inside small pores of some novel structured packed beds are numerically studied, where the packed beds with ellipsoidal or non-uniform spherical particles are investigated for the first time and some new transport phenomena are obtained. Three-dimensional Navier–Stokes equations and RNG k–ε turbulence model with scalable wall function are adopted for present computations. The effects of packing form and particle shape are studied in detail and the flow and heat transfer performances in uniform and non-uniform packed beds are also compared with each other. Firstly, it is found that, with proper selection of packing form and particle shape, the pressure drops in structured packed beds can be greatly reduced and the overall heat transfer performances will be improved. The traditional correlations of flow and heat transfer extracted from randomly packings are found to overpredict the pressure drops and Nusselt number for all these structured packings, and new correlations of flow and heat transfer are obtained. Secondly, it is also revealed that, both the effects of packing form and particle shape are significant on the flow and heat transfer in structured packed beds. With the same particle shape (sphere), the overall heat transfer efficiency of simple cubic (SC) packing is the highest. With the same packing form, such as face center cubic (FCC) packing, the overall heat transfer performance of long ellipsoidal particle model is the best. Furthermore, with the same particle shape and packing form, such as body center cubic (BCC) packing with spheres, the overall heat transfer performance of uniform packing model is higher than that of non-uniform packing model. The models and results presented in this paper would be useful for the optimum design of packed bed reactors.     

A Study of Ozone Formation on the Surfaces of Electrodes

It had been previously thought that ozone production occurred in gaseous space, especially the space between electrodes. However, based on our research, we believe that may only be one of the ozone-producing processes. In this study, we aimed to confirm that a third body, which is present at the interface between oxygen gas and a metal electrode, works to compose ozone. Ozone was not observed in pure oxygen (400x10^?6 Nm³/min flow rate) when electrical discharge was supplied after approximately 6 months. The concentration of ozone increased (approximately 0.07 ppm) when nitrogen (approximately 20x10^?6 Nm³/min flow rate) was added to a gas-mixing chamber. A third body was required to produce ozone when an oxygen molecule and an oxygen atom collided. The same phenomenon was observed on the surface of a copper anode. A simulation confirmed this. Using an industrial ozone generator which utilized ceramic dielectrics and expanded metal electrodes, an increase in the temperature of the cooling water led to a proportional decrease in ozone concentration. After changing from the titanium electrode to a nickel electrode and an antimony electrode, we observed the difference in the enthalpy changes which were calculated using van't Hoff's formula. The antimony electrode increases the efficiency of the ozone generator to produce ozone. We have come to believe that ozone can be composed on the surface of a metal electrode.     

Precise Synthesis of Novel Ferrocene-Based Star-Branched Polymers by Using Specially Designed 1,1-Diphenylethylene Derivatives in Conjunction with Living Anionic Polymerization

The precise synthesis of novel ferrocene-based regular and asymmetric star-branched polymers by a methodology using specially designed 1,1-diphenylethylene derivatives in conjunction with living anionic polymerization of ferrocenylmethyl methacrylate (FMMA) is described. The methodology involves three reaction steps, i.e., (1) introduction of 3-(tert-butyldimethylsilyloxymethyl)phenyl (SMOP) group(s) at the polymer chain end or in-chain, (2) conversion of the SMOP group(s) to α-phenyl acrylate function(s), and (3) a linking reaction of the α-phenyl acrylate function(s) with the living anionic polymer of FMMA or methyl methacrylate. By developing this methodology, a variety of 3-arm \textAA^￠₂ {\text{AA}^{\prime}_{2}} , A₂B, AB₂, ABC and 4-arm A₄, A₃B, A₂B₂, A₂BC, and ABC₂ star-branched polymers with well-defined structures have been successfully synthesized. The A, B, and C segments are poly(FMMA), polystyrene, and poly(methyl methacrylate), respectively.     

Genetically encoded optical probe for detecting release of proteins from mitochondria toward cytosol in living cells and mammals

We developed a genetically encoded bioluminescence indicator for monitoring the release of proteins from the mitochondria in living cells. The principle of this method is based on reconstitution of split Renilla reniformis luciferase (Rluc) fragments by protein splicing with an Ssp DnaE intein. A target mitochondrial protein connected with an N-terminal fragment of Rluc and an N-terminal fragment of DnaE is expressed in mammalian cells. If the target protein is released from the mitochondria toward the cytosol upon stimulation with a specific chemical, the N-terminal Rluc meets the C-terminal Rluc connected with C-terminal DnaE in the cytosol, and thereby, the full-length Rluc is reconstituted by protein splicing. The extent of release of the target fusion protein is evaluated by measuring activities of the reconstituted Rluc. To test the feasibility of this method, here we monitored the release of Smac/DIABLO protein from mitochondria during apoptosis in living cells and mice. The present method allowed high-throughput screening of an apoptosis-inducing reagent, staurosporine, and imaging of the Smac/DIABLO release in cells and in living mice. This rapid analysis can be used for screening and assaying chemicals that would increase or inhibit the release of mitochondrial proteins in living cells and animals.