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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.

The immunomodulating effect of phlorotannin was investigated in mice stimulated by ovalbumin. When analyzing the main components of phlorotannin concentrate (PTC) from Eisenia nipponica, seven phlorotannins [eckol, 6,6'-bieckol, 6,8'-bieckol, 8,8'-bieckol, dieckol, phlorofucofuroeckol (PFF)-A, and PFF-B] were detected. These phlorotannins accounted for approximately 80% of PTC. Oral administration of PTC to mice daily for 21 days reduced serum immunoglobulin E (IgE) and total IgG

Chapter 3 covers various electromagnetic phenomena. These include geometrical effects and dynamic phenomena that were not treated in Chap. 2. The rectifying effect in the DC current-voltage characteristics in a superposed AC magnetic field, flux jumps, surface irreversibility, and DC susceptibility in a varying temperature are also included. In addition, it is shown that an abnormal reduction in losses occurs, deviating from the prediction of the critical state model when an AC magnetic field is applied to a superconductor smaller than the pinning correlation length called Campbell’s AC penetration depth. This is attributed to the reversible motion of flux lines limited within pinning potential wells. In high-temperature superconductors the superconducting current sustained by flux pinning appreciably decays with time due to the thermal agitation of flux lines. This phenomenon, which is called flux creep, is also discussed. In extreme cases the critical current density is reduced to zero at some magnetic field called the irreversibility field. The principles used to determine the irreversibility field are described, and the result is applied to high-temperature superconductors in Chap. 8.

Chapter 7 covers the summation theories that predict the global pinning force density as a function of the elementary pinning force and number density of pinning centers. First, the statistical theory of Labusch is discussed. This theory predicted that the pinning force density has non-zero value for the elementary pinning force above the threshold value. This condition is identical with the condition of the hysteresis loss, and this theory is consistent with the dynamic theory. However, this theoretical prediction is significantly contradictory to experiments. Although the fundamental threshold problem was resolved by Larkin and Ovchinnikov, who showed that a long-range order does not exist in the flux line lattice, quantitative disagreements are sometimes found between their theory and experiments. In the coherent potential approximation theory the statistical method is used with taking into account the lack of long range order, and the compatibility of the threshold problem and the instability of flux motion is obtained. A detailed comparison is made between the theories and experiments. The saturation phenomenon observed in metallic superconductors at high fields is also introduced. The pinning potential energy important for the analysis of flux creep is also derived.

Chapter 8 covers the various properties of high-temperature superconductors. These superconductors show significant anisotropy due to the two-dimensional crystal structure composed of superconducting CuO2 layers and insulating block layers. This makes the states of flux lines extremely complicated. Various phase transitions of the flux line system to be pinned and the mechanisms responsible are reviewed. In particular, the transitions in which the pinning plays an important role, i.e., the order-disorder transition associated with the peak effect of critical current density and the glass-liquid transition associated with the irreversibility field, are discussed in detail. The influences on these transitions, not only of the flux pinning strength and the anisotropy of the superconductor, but also of the electric field and the specimen size are discussed. Y-123, Bi-2212, and Bi-2223, which have been developed for applications, are at the focus of the discussion, and their pinning properties and recent progress are introduced. In particular, the effect of nanorods introduced into Y-123 coated conductors as artificial pinning centers is reviewed.

The main advantage of superconductors, that these materials can transport electric current without energy dissipation, is achieved by the mechanism of flux pinning. Quantized flux lines that contain superconducting structure inside do not move under interaction with defects in the superconductor, even when the Lorentz force is present due to the current. As a consequence, no electromotive force appears, resulting in no energy dissipation. The mechanism of flux pinning is, in principle, reversible with respect to the motion of flux lines. The observed results are commonly irreversible, however, as described by the critical state model, which assumes that there is a balance between the Lorentz force and the irreversible pinning force. In this Chapter, the summation theory is introduced, which is used to analytically determine the critical current density, i.e., the maximum non-dissipative current density. The reason why the resultant electromagnetic phenomena become irreversible is clarified, even though the fundamental flux pinning mechanism is reversible. The irreversibility in flux pinning phenomena does not originate from the breaking of time reversal symmetry, but is of another type, such as friction, that is non-dissipative in stationary condition, although it causes energy dissipation in motion due to the applied force.

We learned that conductors are equipotential in the static condition in the last chapter. We determined the electric potential and electric field strength around a conductor and the distribution of electric charge were determined for simple cases. Most cases involve more than one conductor rather than a single conductor. In this chapter we cover a conductor system, which consists of two or more conductors.

If the \({\varvec{E}}\)-\({\varvec{B}}\) analogy, which is current in the present electromagnetism, is perfect, it seems to be natural that some magnetic material must exist that keeps the interior magnetic flux density \({\varvec{B}}\) zero, corresponding to a conductor that keeps its interior electric field \({\varvec{E}}\) zero. This is in fact a superconductor, which really exists. Hence, if someone would have assumed the existence of such a magnetic material based on this analogy in the 19th century, he would have predicted the superconductor, since it is possible to show that the electrical resistivity of this material must be zero by using Maxwell’s theory. The magnetic phenomena exhibited by superconductors correspond to electric phenomena exhibited by conductors in various aspects, including this point. In this chapter it is shown that introduction of the magnetic phenomena of superconductors into electromagnetism is inevitable to make the \({\varvec{E}}\)-\({\varvec{B}}\) analogy more rigorous. Reference [1] covers the topical area in this chapter.

In this chapter fundamental properties such as quantization of magnetic flux, the normal core in the central region in each packet of quantized magnetic flux, and the induced electric field under the motion of quantized magnetic flux driven by the Lorentz force are described by using the Ginzburg–Landau theory. These are important for understanding the electromagnetic characteristics of superconductors that will be introduced in Chap. 5. Reference [1] covers a wide area of the material in this chapter.

We previously found a lipophilic fraction of the methanol/chloroform extract of a brown alga, Eisenia nipponica, that had an antiallergic effect in a murine ear swelling test. In this study, we purified the active component from the lipophilic fraction using high performance liquid chromatography and analyzed the mass and nuclear magnetic resonance spectra. This uncovered the phlorotannin dieckol, which exhibited antiallergic effects in an ear swelling test using mice sensitized by arachidonic acid, 12-O-tetradecanoylphorbol-13-acetate, and oxazolone. Mechanistic investigations indicated that dieckol suppressed degranulation, chemical mediator release, and the expression of mRNA such as cyclooxygenase-2, interleukin-6, and tumor necrosis factor-α in rat basophilic leukemia-2H3 cells. In summary, we isolated dieckol from E. nipponica and demonstrated its antiallergic mechanisms. PRACTICAL APPLICATIONS: As the incidence of allergies increases worldwide, so too does the demand for food components with antiallergic and anti-inflammatory properties. Given this trend, we focused on a brown alga that displays a variety of bioactivities. Here, we have isolated dieckol from the antiallergic lipophilic fraction of E. nipponica and found that it possesses diverse physiological activities that may prevent lifestyle-related diseases. Consequently, dieckol or the alga containing this phlorotannin could be used as a health food ingredient to combat not only allergies, but also variety of disorders including the undesirable effects of aging.

The critical current of a coaxial cable made of Bi-2223 tapes was investigated to survey underlying problems, especially for the resistive voltage caused by current transfer, for the standardization of test method of the critical current of superconducting AC power cables. Five voltage taps were attached on the copper sheath of 80 mm long, which is used as a part of the current lead, on both ends for the inner conductor layer and outer shield layer. The current transfer was theoretically examined especially for the outer shield layer of a simple structure. The resistive component in the measured voltage was calculated as a function of the position of the voltage tap, and it can be shown that the critical current is correctly obtained using the electric field criterion after subtracting the resistive component, as is usually done in experiments. These results are compared with the observed results.

In this study, we designed a power cable based on the longitudinal magnetic field (LMF) effect using an iterative approximation method. An evaluation of the cable shows that it is more efficient than conventional-design power cables. A cable with four inner layers and four shield layers and a maximum winding angle of 30° had a current capacity of more than 10 kA. Based on calculation results, we fabricated a 2-m-long LMF power cable and a conventional-design power cable. Experimental results show that the proposed power cable can carry more current (8.8% more current per tape and 18% more current overall) than a conventional-design power cable due to the LMF effect. These results well agree with the theoretical calculation results.

The effects of a short chilled storage period before freezing, frozen storage temperature, and freezing rate on lipid oxidation of bluefin tuna (Thunnus thynnus) meat during frozen storage were investigated. After 12-months storage, all samples had increased in peroxide value though they were less at the lower temperatures (−45 and −60°C). Peroxide values in all samples stored at −20°C increased after 3 months storage, particularly those processed and stored 51 h after harvest. The lowest increase in peroxide value occurred in the samples frozen rapidly 3 h after harvest. Vitamin E levels decreased faster during frozen storage at −20°C. There were no apparent differences in levels of triacylglycerides nor in n-3 fatty acid levels between treatments, storage periods, and storage temperatures. After 12-months storage, headspace oxidative volatiles were highest in samples stored at −20°C and lowest in those stored at −60°C. Lipid oxidation in tuna meat stored at −45°C is similar to that at −60°C, and...

This study investigated the anti-allergic effect of a diethyl ether fraction from dried Sargassum fusiforme. In vivo experiments showed that percutaneous administration of this fraction suppressed mouse ear swelling induced by three types of sensitizers (arachidonic acid, 12-O-tetradecanoylphorbol-13-acetate and oxazolone). At a dose of 0.1 mg/mouse, the suppression ratios were from 47 to 61 %. Oral administration of the fraction also suppressed mouse ear swelling. At a dose of 1 mg/mouse, the suppression ratios were from 69 to 92 % which were comparable to those obtained by the typical natural inhibitor, epigallocatechin gallate (EGCG). In vitro experiments were performed to elucidate the inhibitory effects of the fraction on the enzymatic activities (phospholipase A2, cyclooxygenase-2, lipoxygenase and hyaluronidase) involved in inflammation and degranulation in rat basophilic leukemia (RBL)-2H3 cells to understand the mechanism that underlies the suppression of mouse ear swelling. Similar to EGCG, the fraction inhibited the enzymatic activities tested and suppressed degranulation in RBL cells in a dose-dependent manner. Therefore, the active components present in this S. fusiforme fraction achieve the anti-inflammatory effects by inhibiting the enzymatic activities and degranulation in the ear of mice. Thus, S. fusiforme and its diethyl ether fraction could be useful ingredients in functional foods.

The critical current density (Jc) properties of the Artificial Pinning Center (APC) introduced YBa2Cu3O7 (YBCO) films in the longitudinal magnetic field were measured. Y2O3 or Y2BaCuO5 (Y211) was introduced as APCs to YBCO, and YBCO films with APC were fabricated on SrTiO3 single crystal substrate. The sizes of Y2O3 and Y211 were 5—10 nm and 10—20 nm, respectively. As a result, Jc enhancement in the longitudinal magnetic field was observed in Y2O3 introduced YBCO films. However, it was not observed in Y211 introduced YBCO films. Therefore, it was considered that Jc properties in the longitudinal magnetic field were affected by introducing of small size APC, and it was necessary that APC does not disturb the current pathway in the superconductor., 28th International Symposium on Superconductivity, ISS 2015, November 16-18, 2015, Tokyo, Japan

Innovative dc superconducting cables with higher current-carrying capacity than conventional cables were proposed in previous works. The superior property is brought about by the longitudinal magnetic field that enhances the critical current density. In this work, the current-carrying capacity of a three-layer cable composed of Bi-2223 tapes was theoretically calculated based on the measured critical current density in the longitudinal magnetic field. The obtained current-carrying capacity of the proposed cable is 13.2% higher in comparison with the conventional cable of the same size.

We proposed the innovative force-free superconducting cable with higher current-carrying capacity than conventional superconducting DC cables utilizing the longitudinal magnetic field effect that enhances the critical current density. That is, the critical current density can be enhanced by the longitudinal magnetic field that the conductor itself and the outer shield conductor produce. It means that, if the longitudinal magnetic field can be reduced, the critical current density is appreciably reduced, resulting in an accelerated resistive transition. Such situation can be realized by arranging the copper conductor layers in a suitable structure that transport currents when the superconductors are in resistive state. We propose to arrange the copper conductor layers in the inner and outer conductors to reduce the longitudinal magnetic field by twisting in opposite directions to respective superconducting layers in each conductor region. Various conditions of fault-current limiting can be achieved by arranging the winding angle of the copper layers. Discussion will be given on the fault-current limiting properties of the proposed cable.

The trapped magnetic field properties in superconducting MgB2 bulk magnets with various kinds of shape such as a disk, a ring and a pair of disks were calculated by the finite element method (FEM). For simplicity, field cool magnetization was replaced by a simple magnetization process at constant temperature to obtain equivalent distribution of magnetic field, and the thermal equation in FEM was omitted. It was confirmed that the result of FEM agreed well with the result by analytical method in infinite long cylinder. We compared the trapped magnetic field property between FEM result and experimental result in reference in order to research the simple evaluation method of the trapped magnetic field of MgB2 bulk magnet. It was found that the result of FEM agreed with the experimental result and it can explain the distribution of trapped magnetic field of superconducting MgB2 bulk magnet. From these results, it was found that it was possible to be calculated in various kinds of shape with using simple evaluation by FEM. Therefore, the optimization of the maximum trapped magnetic field in superconducting MgB2 bulk magnet can be discussed., Proceedings of the 27th International Symposium on Superconductivity (ISS 2014) November 25-27, 2014, Tokyo, Japan

In this paper, a round robin test of residual resistance ratio (RRR) is performed for Nb3Sn composite superconductors prepared by an internal tin method by six institutes with the international standard test method described in IEC 61788-4. It was found that uncertainty mainly resulted from determination of the cryogenic resistance from the intersection of two straight lines drawn to fit the voltage versus temperature curve around the resistive transition. The measurement clarified that RRR can be measured with expanded uncertainty not larger than 5% with the coverage factor 2 by using this test method.

As a method of largely reducing the transmission loss in the electric power grid, superconducting direct current (DC) power transmission cable has been investigated. Using superconducting DC power transmission cables, large amounts of current and energy can be transferred compared to conventional copper cables. In this case, an alternating current (AC) is converted to DC and superposed AC which is known as ripple current, and the energy loss by the ripple current is generated. Therefore it is desired to estimate the energy loss density for the case of DC current and superposed AC current for a design of DC transmission cable system. In this study, the hysteresis loss for DC current of 2 kA rectified from 60 Hz alternating current is calculated using the Bean model, and coupling loss was also estimated. The diameter of the cable was 40 mm. The ripple currents generated by multi-pulse rectifiers, 6-pulse, 12-pulse, and 24-pulse were considered. It is found that the total AC loss including the hysteresis loss and the coupling loss is considerably smaller than the supposed heat loss of 0.5 W/m which is obtained with a newly developed cable., 26th International Symposium on Superconductivity (ISS 2013), November 18-20, 2013, Tokyo, Japan

The depairing current density in superconductors is theoretically investigated for magnetization and transport currents. It is found that the depairing current densities in both cases are higher than those predicted by Tinkham. One of the reasons for the higher current densities is that those are obtained at the transition point to the normal state, while Tinkham obtained in the superconducting state far from the transition boundary. Another reason is that the order parameter is larger than the equilibrium value, which contributes not only directly to a higher current density but also to a lower kinetic energy due to the current.

The high upper critical field and low anisotropy of the 122-type iron-based superconductor BaFe2As2 makes it promising for use in superconducting high field magnets. However, its critical current density (J c) in high magnetic fields needs to be further improved. Here we show that for the film prepared by pulsed laser deposition method by controlling the deposition parameters (higher substrate temperature and lower growth rate), the crystallinity of BaFe2(As0.66P0.33)2 (Ba122:P) matrix is improved while maintaining a high density of incoherent BaZrO3 (BZO) nanoparticles (NPs) which together lead to significantly increased self field J c. Our Ba122:P nanocomposite films also exhibit increased in-field J c, reduced angular anisotropy of J c and reduced detrimental effects of thermal fluctuations (creep rate) over a wide range of temperatures and magnetic field strength. The BZO NP doped Ba122:P films show high in-field J c over 2.1 MA cm−2 even at 4 K and 9 T (μ 0 H∣∣c), which is significantly higher than that of standard Ba122:P films and conventional alloy superconducting wires. To understand the contribution of the various pinning centers, we applied a simple model, which was developed for cuprates, to Ba122:P film with all the parameters used derived by fitting to a limited set of experimental data (no free parameters) such that temperature, angle and field properties at other experimental conditions are then calculated. This simple model fits very well to the experimental results in these two very different material systems. We discuss the effectiveness of natural defect and BZO NPs on the ratio of J c to the depairing current density. The superconducting properties for 122-type iron-based superconductors obtained through this work are considered promising for high-field applications.

To determine the anti-allergic effects of Ecklonia kurome, the ethyl acetate fraction from an E. kurome (EEK) extract was compared to the ethyl acetate fraction from an Eisenia arborea (EEA) extract and epigallocatechin gallate (EGCG) for inhibitory effects on inflammation in experimental animals, degranulation in inflammatory lymphocytes and enzymatic activities involved in allergic reactions. EEK was found to inhibit mouse ear oedema by inflammatory inducers (arachidonic acid, 12-O-tetradecanoylphorbol-13-acetate and oxazolone) in a dose-dependent manner, through both topical and oral administrations. EEK also inhibited degranulation in rat basophilic leukaemia cells and enzymatic activities (cyclooxygenase-2, soybean lipoxygenase and phospholipase A2) in a dose-dependent manner. The effects of EEK were generally comparable of those of EEA and EGCG. Therefore, E. kurome and the components in EEK have the benefit of being used not only in common foods, but also more widely as a functional food resource i...

Hydroxy lipids (L-OH) and 4-hydroxy-2-hexenal (HHE) levels as well as other parameters such as lipid level, lipid class, fatty acid composition, and other aldehydes levels in the liver of diseased fish were investigated. Although significant differences in lipid level, lipid class, fatty acid composition, and other aldehyde levels were not always observed between normal and diseased fish, L-OH and HHE levels were significantly higher in the liver of the diseased fish than in that of the normal fish cultured with the same feeds under the same conditions. In the liver of puffer fish (Fugu rubripes) infected with Trichodina, L-OH and HHE levels significantly increased from 25.29 ± 5.04 to 47.70 ± 5.27 nmol/mg lipid and from 299.79 ± 25.25 to 1,184.40 ± 60.27 nmol/g tissue, respectively. When the levels of HHE and other aldehydes in the liver of the normal and diseased puffer fish were plotted, a linear relationship with a high correlation coefficient was observed between HHE and propanal (r 2 = 0.9447). Increased L-OH and HHE levels in the liver of the diseased fish and a high correlation between HHE and propanal in the liver of the normal and diseased fish were also observed in flat fish (Paralichthys olivaceus) infected with streptococcus, yellowtail (Seriola quinqueradiata) infected with jaundice, and amberjack (S. purpurascens) infected with Photobacterium damselae subsp. piscicida.

It is known from experimental data that the critical current of superconducting wires in a longitudinal magnetic field is higher than that in a transverse magnetic field. This property was proposed to apply to DC superconducting cables in our previous paper. Here, we propose a new calculation method of the current-carrying capacity for a new DC superconducting cable. An iteration method is used to calculate the magnetic field and critical current density in each layer and the current-carrying capacity of the cable. This enables us to calculate these quantities even for the cable with a different structure from the force-free one. When the critical current density increases with a longitudinal magnetic field, the optimal structure is found to be close to that of the force free cable. The optimal structure is obtained also when the critical current density decreases slightly with the longitudinal magnetic field. The reason for the enhanced current-carrying capacity even for such a case is a sufficiently larger critical current density in the longitudinal magnetic field than that in the transverse magnetic field., Proceedings of the 25th International Symposium on Superconductivity (ISS 2012) Advances in Superconductivity XXV , December 3-5, 2012, TOWER HALL FUNABORI, Tokyo, Japan

Changes in hydroxyl lipids (L-OHs; a stress level indicator), body weight, triglycerides, fatty acids, and free amino acids (FAAs) were investigated in Decapterus maraudsi caught by purse seine from two different ocean regions near Japan to determine the effect of short-term holding without feeding on the reduction in oxidative stress. In experiment 1, the L-OHs in the dorsal muscle significantly decreased by 9 d, whereas those in the liver decreased significantly by the end of the 33-d holding period. The body weight, lipid content, and triglyceride composition did not change significantly for 9 d and then decreased significantly by 33 d. Fatty acid composition of the dorsal muscle and liver did not change significantly within the holding period. The FAA content in the dorsal muscle did not change until 9 d and then decreased by 33 d. In experiment 2, the L-OHs in the dorsal muscle had significantly increased at 33 d, whereas the levels in the liver of the fish after transport to port were twice...