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The Japanese national project started on standardization of the test method of the DC critical current of superconducting cables. A round robin test of critical current measurement is carried out to survey underlying problems for the standardization. The sample cables are made of Bi-2223 tapes and the inner core conductor has two layers and the outer shield conductor is composed of a single layer. The diameter of the shield layer is about 40 mm and the length of the cable is 2.00 m. The critical current was determined by the electric field criterion of 1 μV/cm. The n value is also measured for the inner core and the outer shield conductor. Three institutes participated in the test for two sample cables. The obtained experimental relative standard deviation for the critical current at 77.30 K is in the range of 0.2 to 1.3%, and is sufficiently small. Hence, it can be said that the present method that is widely used is suitable as a standard test method. On the other hand, the experimental relative standard deviation of the value is in the range of 2.8 to 18.6%, which is relatively large. This is caused by the measurements done at different temperatures.

A large-scale demonstration test of a triaxial high-temperature superconducting (HTS) cable for a practical cable system was performed in a chemical plant of a private company. The 200 m-long HTS (REBCO: REBa2Cu3O7-δ) triaxial cable, which was manufactured by connecting 3 cables using 2 joints via a snake-shaped layout, was laid approximately 5 m higher than ground level, and the cable was cryocooled by circulating liquid nitrogen. For the preverification test, the rise-up test of the liquid nitrogen and the development of technology for bending the cable, joining it, as well as laying and installing it, were conducted. No leakage of liquid nitrogen at the terminal due to damage caused by heat shock or liquid nitrogen drop impact was observed. The pressure required for the liquid nitrogen to achieve a 5 m height was from 27.5 to 33 kPa, which is in good agreement with the calculated pressure of 33.6 kPa. The cooling rate was well controlled, and the desired level of 4 K/h was achieved. The economic challenges and methods of achieving market penetration were also discussed. The goal was to realize a superconducting cable for practical applications, and it was thought that the energy and costs necessary for cryocooling could be drastically reduced by using the existing cold system in the plant. In this way, it is expected HTS cables can achieve low costs and high energy-saving effects and penetrate markets in the future.

Bioleaching of arsenic (As)-rich, so-called “dirty” concentrates can produce additional Cu value from the flotation waste while simultaneously releasing toxic As. This study bioleached three such concentrates of varying pyrite/enargite ratios ([Py]/[Ena] = 0.7, 1.3 and 2.4) at a pulp density of 20%. The dissolution behavior of Cu and As in relation to the solution redox potential (Eh) was studied with and without activated carbon (AC) as a potential Eh-controlling catalyst. At this high pulp density, Eh was naturally suppressed, without a need for AC dosing, to

Sodium metabisulfite (MBS) was used in this study for selective flotation of chalcopyrite and molybdenite. Microflotation tests of single and mixed minerals were performed to assess the floatability of chalcopyrite and molybdenite. The results of microflotation of single minerals showed that MBS treatment significantly depressed the floatability of chalcopyrite and slightly reduced the floatability of molybdenite. The results of microflotation of mixed minerals demonstrated that the MBS treatment could be used as a selective chalcopyrite depressant in the selective flotation of chalcopyrite and molybdenite. Furthermore, the addition of diesel oil or kerosene could significantly improve the separation efficiency of selective flotation of chalcopyrite and molybdenite using MBS treatment. A mechanism based on X-ray photoelectron spectroscopy analysis results is proposed in this study to explain the selective depressing effect of MBS on the flotation of chalcopyrite and molybdenite.

The copper ore in Chilean copper porphyry deposits is often associated with molybdenum minerals. This copper–molybdenum (Cu–Mo) sulfide ore is generally mined from various locations in the mining site, thus, the mineral composition, oxidation degree, mineral particle size, and grade vary. Therefore, in the mining operation, it is common to blend the ores mined from various spots and then process them using flotation. In this study, the floatability of five types of Cu–Mo ores and the blending of these ores in seawater was investigated. The oxidation degree of these Cu–Mo ores was evaluated, and the correlation between flotation recovery and oxidation degree is presented. Furthermore, the flotation kinetics of each Cu–Mo ore were calculated based on a mineralogical analysis using mineral liberation analysis (MLA). A mineralogical prediction model was proposed to estimate the flotation behavior of blended Cu–Mo ore as a function of the flotation behavior of each Cu–Mo ore. The flotation results show that the recovery of copper and molybdenum decreased with the increasing copper oxidization degree. In addition, the recovery of blended ore can be predicted via the flotation rate equation, using the maximum recovery (Rmax) and flotation rate coefficient (k) determined from the flotation rate analysis of each ore before blending. It was found that Rmax and k of the respective minerals slightly decreased with increasing the degree of copper oxidation. Moreover, Rmax varied greatly depending on the mineral species. The total copper and molybdenum recovery were strongly affected by the degree of copper oxidation as the mineral fraction in the ore varied greatly depending upon the degree of oxidation.

OBJECTIVES: Thiamine acts as a coenzyme (prosthetic group) after converting to thiamine pyrophosphate in crucial metabolic enzymes of pyruvate dehydrogenase, α-ketoglutarate dehydrogenase and transketolase. Theoretically, thiamine should not be consumed by an increase in the number of substrates for those enzymes. However, thiamine is often described to be consumed by excessive carbohydrate intake. Such a possible misunderstanding is assessed in the relevant literature. METHODS: The original paper (Elmadfa, et al. Int J Vitam Nutr Res 2001), which seems to mislead the reader into considering an increase in thiamine requirement for excessive carbohydrate intake, and the relevant papers were reviewed. RESULTS: The original paper demonstrated that increases in carbohydrate intake from 55% to 65% and 75% of total energy caused decreases in plasma and urine concentrations of thiamine, while erythrocyte transketolase activity remained unchanged. This seems to misleadingly support the idea that excessive carbohydrate intake increases the thiamine requirement for carbohydrate metabolism. It could be interpreted as the decreases of thiamine concentrations were observed only during an adaptation period. It was reported that diabetic patients had low plasma thiamine levels in association with increased renal clearance and fractional excretion of thiamine, without a decrease in erythrocyte transketolase activity (Thornalley, et al. Diabetologia 2007). As a similar case of possible misinterpretation, a case report (Watson, et al. Ir J Med Sci 1981) demonstrated that glucose loading precipitated thiamine deficiency in malnourished patients with latent thiamine deficiency. CONCLUSIONS: From the relevant literature, it is inferred that excessive carbohydrate intake in people without hyperglycemia could lead to a small increase, if any, in urinary thiamine excretion, but not to an increase in thiamine requirement for glucose metabolism. Even in the academic field, it seems that thiamine is often misunderstood to be consumed by excessive carbohydrate intake. FUNDING SOURCES: None.

Overcoming the slow-leaching kinetics of refractory primary copper sulfides is crucial to secure future copper sources. Here, the effect of carbon was investigated as a catalyst for a bioleaching reaction. First, the mechanism of carbon-assisted bioleaching was elucidated using the model chalcopyrite mineral, under specified low-redox potentials, by considering the concept of Enormal. The carbon catalyst effectively controlled the Eh level in bioleaching liquors, which would otherwise exceed its optimal range (0 ≤ Enormal ≤ 1) due to active regeneration of Fe3+ by microbes. Additionally, Enormal of ~0.3 was shown to maximize the carbon-assisted bioleaching of the model chalcopyrite mineral. Secondly, carbon-assisted bioleaching was tested for three types of chalcopyrite/enargite-bearing complex concentrates. A trend was found that the optimal Eh level for a maximum Cu solubilization increases in response to the decreasing chalcopyrite/enargite ratio in the concentrate: When chalcopyrite dominates over enargite, the optimal Eh was found to satisfy 0 ≤ Enormal ≤ 1. As enargite becomes more abundant than chalcopyrite, the optimal Eh for the greatest Cu dissolution was shifted to higher values. Overall, modifying the Eh level by adjusting AC doses to maximize Cu solubilization from the concentrate of complex mineralogy was shown to be useful.

A new ternary layered pnictide, Li1-xSn2+xP2, was synthesized by a solid-state reaction and its properties were examined to explore its potential as a multifunctional material. The compound crystallizes in a layered structure in the R-3m space group with buckled honeycomb Sn-P layers separated by mixed-occupation Li/Sn layers. Crystal structure analysis using synchrotron X-ray diffraction showed that the substitution degree of Li by Sn (x) is approximately 0.3. Local ordering of Li/Sn occupation was demonstrated using 31P nuclear magnetic resonance analysis. The lattice thermal conductivity of Li1-xSn2+xP2 was found to be relatively low (1.2 Wm−1K−1 at 525 K). The room-temperature electrical resistivity of Li1-xSn2+xP2 was found to be 0.3-0.4 mohm cm and metallic conductivity was observed down to 0.5 K. First-principles calculations demonstrated that the electronic structure and Fermi energy of Li1-xSn2+xP2 are significantly dependent upon x. Electrochemical measurements using a single-particle technique demonstrated the activity of Li1-xSn2+xP2 as an anode material for rechargeable Li-ion batteries.

We report on a systematic study of Hall effect using high quality single crystals of type-II Weyl semimetal WTe 2 with the applied magnetic field B//c . The residual resistivity ratio of 1330 and the large magnetoresistance of 1.5 × 10 6 % in 9 T at 2 K, being in the highest class in the literature, attest to their high quality. Based on a simple two-carrier model, the densities ( n e and n h ) and mobilities ( μ e and μ h ) for electron and hole carriers have been uniquely determined combining both Hall- and electrical-resistivity data. The difference between n e and n h is ~ 1% at 2 K, indicating that the system is in an compensated condition. The negative Hall resistivity growing rapidly below ~ 20 K is due to a rapidly increasing μ h /μ e approaching one. Below 3 K in a low field region, we found the Hall resistivity becomes positive, reflecting that μ h /μ e finally exceeds one in this region. These anomalous behaviors of the carrier densities and mobilities might be associated with the existence of a Lifshitz transition and/or the spin texture on the Fermi surface.

Recently CeOBiS2 system without any fluorine doping is found to show superconductivity posing question on its origin. Using space resolved ARPES we have found a metallic phase embedded in the morphological defects and at the sample edges of stoichiometric CeOBiS2. While bulk of the sample is semiconducting, the embedded metallic phase is characterized by the usual electron pocket at X point, similar to the Fermi surface of doped BiS2-based superconductors. Typical size of the observed metallic domain is larger than the superconducting correlation length of the system suggesting that the observed superconductivity in undoped CeOBiS2 might be due to this embedded metallic phase at the defects. The results also suggest a possible way to develop new systems by manipulation of the defects in these chalcogenides with structural instability.

The bulk electronic structure of ${T}_{d}$-${\mathrm{MoTe}}_{2}$ features large hole Fermi pockets at the Brillouin zone center ($\mathrm{\ensuremath{\Gamma}}$) and two electron Fermi surfaces along the $\mathrm{\ensuremath{\Gamma}}\text{\ensuremath{-}}X$ direction. However, the large hole pockets, whose existence has important implications for the Weyl physics of ${T}_{d}$-${\mathrm{MoTe}}_{2}$, has never been conclusively detected in quantum oscillations. This raises doubt about the realizability of Majorana states in ${T}_{d}$-${\mathrm{MoTe}}_{2}$, because these exotic states rely on the existence of Weyl points, which originated from the same band structure predicted by density functional theory (DFT). Here, we report an unambiguous detection of these elusive hole pockets via Shubnikov--de Haas (SdH) quantum oscillations. At ambient pressure, the quantum oscillation frequencies for these pockets are 988 and 1513 T, when the magnetic field is applied along the $c$ axis. The quasiparticle effective masses ${m}^{*}$ associated with these frequencies are 1.50 and 2.77 ${m}_{e}$, respectively, indicating the importance of Coulomb interactions in this system. We further measure the SdH oscillations under pressure. At 13 kbar, we detected a peak at 1798 T with ${m}^{*}=2.86{m}_{e}$. Relative to the oscillation data at a lower pressure, the amplitude of this peak experienced an enhancement, which can be attributed to the reduced curvature of the hole pockets under pressure. Combining our experimental data with $\text{DFT}+U$ calculations, where $U$ is the Hubbard parameter, our results shed light on why these important hole pockets have not been detected until now.

We report the Se substitution effects on the crystal structure, superconducting properties, and valence states of self-doped BiCh2-based compound CeOBiS2-xSex. Polycrystalline CeOBiS2-xSex samples with x = 0-1.0 were synthesized. For x = 0.4 and 0.6, bulk superconducting transitions with a large shielding volume fraction were observed in magnetic susceptibility measurements; the highest transition temperature (Tc) was 3.0 K for x = 0.6. A superconductivity phase diagram of CeOBiS2-xSex was established based on Tc estimated from the electrical resistivity and magnetization measurements. The emergence of superconductivity in CeOBiS2-xSex was explained with two essential parameters of in-plane chemical pressure and carrier concentration, which systematically changed with increasing Se concentration., Comment: 15 pages, 8 figures

Recently, we reported the observation of superconductivity at ~0.5 K in a La2O2M4S6-type (M: metal) layered compound La2O2Bi3AgS6, which is a layered system related to the BiS2-based superconductor system but possesses a thicker Bi3AgS6-type conducting layer. In this study, we have developed the La2O2Bi3AgS6-type materials by element substitutions to increase the transition temperature (Tc) and to induce bulk nature of superconductivity. A resistivity anomaly observed at 180 K in La2O2Bi3AgS6 was systematically suppressed by Sn substitution for the Ag site. By the Sn substitution, Tc increased, and the shielding volume fraction estimated from magnetization measurements also increased. The highest Tc (=2.3 K) and the highest shielding volume fraction (~20%) was observed for La2O2Bi3Ag0.6Sn0.4S6. The superconducting properties were further improved by Se substitutions for the S site. By the combinational substitutions of Sn and Se, bulk-superconducting phase of La2O2Bi3Ag0.6Sn0.4S5.7Se0.3 with a Tc of 3.0 K (Tconset = 3.6 K) was obtained.

Hyponatremia is a common but important electrolyte disorder mostly complicated with other diseases. Recently, we experienced a case of a hypertensive patient in her seventies taking a thiazide diuretic, who presented with disorientation due to severe hyponatremia (serum sodium level, 104 mmol/l) on admission. Taking this opportunity, patients with profound hyponatremia (