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Contrary to prevailing thought, the salt content of supernatants is found to dictate reactivity differences of different preparation methods of Rieke zinc toward oxidative addition of organohalides. This conclusion is established through combined single-particle microscopy and ensemble spectroscopy experiments, coupled with careful removal or keeping of the supernatants during Rieke zinc preparations. Fluorescence microscopy experiments with single-Rieke-zinc-particle resolution determined the microscale surface reactivity of the Rieke zinc in the absence of supernatants, thus pinpointing its inherent reactivity independent of the convoluting supernatant composition. In parallel experiments, scanning electron microscopy, energy-dispersive spectroscopy, X-ray photoelectron spectroscopy, and inductively coupled plasma-mass spectrometry characterized the zinc metal chemical composition at the bulk and single-particle levels. Proton nuclear magnetic resonance spectroscopy kinetics characterized bench-scale Rieke zinc reactivity in the presence and absence of different supernatants and exogenous salt additives. Together, these experiments show that the differences in reactivity from sodium-reduced vs lithium-reduced Rieke zinc arise from the residual salts in the supernatant rather than the differing salt compositions of the solids. This supernatant salt also determines the structure of the ultimate organozinc product, generating either the diorganozinc or monoorganozinc halide complex. That different organozinc complexes formed upon direct insertion to different preparations of Rieke zinc was not previously reported, despite Rieke zinc's widespread use. These findings impact organozinc-reagent and nanomaterial synthesis by showing that, unexpectedly, desired Rieke zinc reactivity can be achieved through simple addition of soluble salts to solutions that were used to prepare the metals─a substantially easier synthetic manipulation than solid composition and morphology control.

Yields of organoindium reagents synthesized from indium metal were previously reported to be highly dependent on metal batch and supplier due to the presence or absence of anticaking agent. Here, single-particle fluorescence microscopy established that MgO, an additive in some batches nominally for anticaking, significantly increased the physisorption of small-molecule organics onto the surface of the resulting MgO-coated indium metal particles. An inert and relatively nonpolar boron dipyrromethene fluorophore with a hydrocarbon tail provided a sensitive probe for this surface physisorption. SEM images revealed markedly different surface properties of indium particles either with or without MgO, consistent with their different physisorption properties observed by fluorescence microscopy. We further documented incomplete commercial bottle labeling regarding the presence and composition of this anticaking agent, both within our laboratory and previously in the literature, which may complicate reproducibility between laboratories. Trimethylsilyl chloride pretreatment, a step employed in a subset of reported synthetic procedures, removed the anticaking agent and produced particles with similar physisorption properties as commercial batches of indium powder distributed without the anticaking agent. These data indicate the possibility of an additional substrate/catalyst physisorption mechanism by which the anticaking agent may be influencing synthetic procedures that generate organoindium reagents from indium metal, in addition to simple anticaking.

Solvent effects are often difficult to understand in cases where reaction intermediates, and thus their differential behaviour in different solvents, are not directly observable by traditional ensemble analytical techniques. Herein, the sensitivity of single-particle fluorescence microscopy uniquely enables direct observation of organozinc intermediates and solvent effects on their build-up and persistence. When combined with NMR spectroscopy, these imaging data pinpoint the previously elusive mechanistic origin of solvent effects in the synthesis of widely used organozinc reagents. These findings characterize the acceleration of oxidative addition of the starting organoiodide to the surface of zinc metal in DMSO relative to THF, but once formed, surface intermediates display similar persistence in either solvent. The current studies are the first demonstration of a highly sensitive, single-particle fluorescence microscopy technique to pinpoint otherwise elusive solvent effects in synthetic chemistry.

This experiment was performed to investigate the effects of increases in passively acquired immunoglobulin G (IgG) by difructose anhydride (DFA) III supplementation on subsequent serum IgG concentration and health status in calves during the preweaning period. Thirty newborn female Holstein calves were paired by birth order, and 2 calves in each pair were fed 2 L of the same batch of colostrum within 2 h and at 10 h after birth, and followed by 2 L of the same batch of pooled colostrum at 20 h after birth. One calf from each pair was assigned to the control (n = 15) or treatment (n = 15) group. All calves in the treatment group received 18 g of DFA III at each feeding from birth to 7 d of age, whereas calves in the control group did not receive DFA III. Blood samples were collected before feeding at 0, 10, 20, and 36 h, and 4 and 7 d of age, and sampling was repeated at 7-d intervals thereafter until 49 d of age for serum IgG analysis. Calves were monitored daily for diarrhea and respiratory diseases. Serum IgG concentrations peaked at 36 h of age in both groups. Apparent efficiency of IgG absorption and peak serum IgG concentration were higher in the treatment group than in the control group. Using multiple regression analysis, we showed that peak serum IgG concentration in the newborn calves was positively correlated with colostral IgG concentration and DFA III supplementation. Moreover, peak serum IgG concentration (36 h of age) positively influenced subsequent serum IgG concentration until 35 d of age for all calves in both groups. The treatment group had higher serum IgG concentration from 20 h to 21 d of age than the control group. However, we detected no differences between the groups in number of calves with diarrhea or respiratory disease.

The JT-60SA superconducting tokamak is being constructed under dual projects, the EU-JA international collaboration framework and Japanese national programme. To suppress magnetic field error to less than 0.01% with respect to the toroidal magnetic field for good confinement of plasma, QST has developed a precise onsite assembly technology of tokamak components such as vacuum vessel (VV) and toroidal magnetic field coils (TFC) with size of over 10-m scale. Prior to an onsite assembly, the assembly process is carefully simulated in a three dimension CAD model, through which the location and number of the reference points for the assembly are evaluated to determine each component position. In the onsite assembly, the tokamak components are positioned by measuring with the laser tracker of a 0.5 mm spatial resolution and assembled by adjusting with shims and splice plates. The onsite assembly of the VV 340° sector has been succeeded in an allowable accuracy of +8/−4 mm with the 10 m diameter by welding sectors, each of which was circumferentially segmented and manufactured by taking into account the deformation due to the welding. The remaining 20° sector will be installed after the TF coils installation. The metrology developed for the onsite assembly of the JT-60SA is expected to be applicable to ITER whose size is the double of JT-60SA.

The everyday environment brings to our sensory systems competing inputs from different modalities. The ability to filter these multisensory inputs in order to identify and efficiently utilize useful spatial cues is necessary to detect and process the relevant information. In the present study, we investigate how feature-based attention affects the detection of motion across sensory modalities. We were interested to determine how subjects use intramodal, cross-modal auditory, and combined audiovisual motion cues to attend to specific visual motion signals. The results showed that in most cases, both the visual and the auditory cues enhance feature-based orienting to a transparent visual motion pattern presented among distractor motion patterns. Whereas previous studies have shown cross-modal effects of spatial attention, our results demonstrate a spread of cross-modal feature-based attention cues, which have been matched for the detection threshold of the visual target. These effects were very robust in comparisons of the effects of valid vs. invalid cues, as well as in comparisons between cued and uncued valid trials. The effect of intramodal visual, cross-modal auditory, and bimodal cues also increased as a function of motion-cue salience. Our results suggest that orienting to visual motion patterns among distracters can be facilitated not only by intramodal priors, but also by feature-based cross-modal information from the auditory system.

The incidence of hypocalcemia increases in high-parity dairy cows because resorption of bone Ca is delayed in these animals, and they appear to have a reduced ability to absorb Ca from the intestine during the early postpartum period. Difructose anhydride (DFA) III has been shown to promote the absorption of intestinal Ca via a paracellular pathway. However, past studies have not reported this effect in peripartum dairy cows. Therefore, we investigated the effect of DFA III supplementation on Ca metabolism during the peripartum period to determine whether DFA III promotes intestinal Ca absorption via this route. Seventy-four multiparous Holstein cows were separated into DFA and control groups based on their parity and body weight. The feed of the DFA group was supplemented with 40g/d of DFA III from -14 to 6d relative to calving. The control group did not receive DFA III. At calving (0h relative to calving), serum Ca declined below 9mg/dL in both groups. However, serum Ca concentrations were greater in the DFA group than in the control group at 6, 12, 24, and 48h relative to calving, and the time required for serum Ca to recover to 9mg/dL during the postpartum period was shorter in the high-parity cows in the DFA group than in those in the control group. Parathyroid hormone concentrations increased immediately after calving in both groups and were greater in the control group than in the DFA group at 12 and 24h relative to calving. Serum 1,25-dihydroxyvitamin D concentrations increased at 0 and 12h relative to calving in both groups and were higher in the control group than in the DFA group at 72h relative to calving. Serum concentrations of the bone-resorption marker cross-linked N-telopeptide of type I collagen (NTX) were not different between the groups during peripartum period, and serum NTX in all cows was lower at 0, 6, 12, 24, 48, and 72h relative to calving than at -21, 4, and 5d relative to calving. Thus, DFA treatment induced faster recovery of serum Ca, although bone resorption was restrained. In conclusion, DFA III promotes intestinal passive Ca absorption via the paracellular pathway during the early postpartum period; this absorption is unaffected by aging.

SummaryThe everyday environment brings about many competing inputs from different modalities to our sensory systems. The ability to filter these multisensory inputs in order to identify and efficiently utilize useful spatial cues is necessary to detect and process the relevant information. In the present study, we investigate how feature-based attention affects the detection of motion across sensory modalities. We were interested to determine how subjects use intramodal, crossmodal auditory, and combined audiovisual motion cues to attend to specific visual motion signals. The results show that in most cases, both visual and auditory cues enhance feature-based orienting to a visual motion pattern that is presented among distractor patterns. Furthermore, in many cases, detection of transparent motion patterns was significantly more accurate after combined visual-auditory than unimodal attention cues. Whereas previous studies have shown crossmodal effects of spatial attention, our results demonstrate a spread of crossmodal feature-based attention cues, which have been matched for the detection threshold of the visual target. These effects were evident in comparisons between cued and uncued conditions, as well as in analyses comparing the effects of valid vs. invalid cues.

Requirements to control the large decrease in serum calcium (Ca) due to parturition and to increase the feed intake soon after parturition have been well accepted in dairy cows. This study was aimed to investigate the feed intake affected by serum Ca concentration with difructose anhydride (DFA) III supplement in dairy cows soon after parturition. Fourteen transition Holstein cows were divided into DFA and control (CONT) groups within 1 to 5 parity variations in each group. Measurement schedule for an individual cow was from 14 d before parturition to 7 d following parturition. The cows in DFA group were supplied 0.2 kg/head/d of DFA III feed containing 40 g of pure DFA III while the cows in CONT group received no DFA III. Other feeding procedures were the same for all cows in both groups. At parturition (d 0), serum Ca concentration sharply declined in both groups (p9.0 mg/dL) tended to be faster in DFA group (12 h) than in the CONT group (48 h), but the differences were not significant. Active ruminal contraction was observed in DFA group at following parturition of d 1 (p

Cysteinate oxygenation is intimately tied to the function of both cysteine dioxygenases (CDOs) and nitrile hydratases (NHases), and yet the mechanisms by which sulfurs are oxidized by these enzymes are unknown, in part because intermediates have yet to be observed. Herein, we report a five-coordinate bis-thiolate ligated Fe(III) complex, [FeIII(S2Me2N3-(Pr,Pr))]+ (2), that reacts with oxo atom donors (PhIO, IBX-ester, and H2O2) to afford a rare example of a singly oxygenated sulfenate, [FeIII(η2-SMe2O)(SMe2)N3(Pr,Pr)]+ (5), resembling both a proposed intermediate in the CDO catalytic cycle and the essential NHase Fe-S(O)Cys114 proposed to be intimately involved in nitrile hydrolysis. Comparison of the reactivity of 2 with that of a more electron-rich, crystallographically characterized derivative, [FeIIIS2Me2NMeN2amide(Pr,Pr)]− (8), shows that oxo atom donor reactivity correlates with the metal ion’s ability to bind exogenous ligands. Density functional theory calculations suggest that the mechanism of S-oxygenation does not proceed via direct attack at the thiolate sulfurs; the average spin-density on the thiolate sulfurs is approximately the same for 2 and 8, and Mulliken charges on the sulfurs of 8 are roughly twice those of 2, implying that 8 should be more susceptible to sulfur oxidation. Carboxamide-ligated 8 is shown to be unreactive towards oxo atom donors, in contrast to imine-ligated 2. Azide (N3−) is shown to inhibit sulfur oxidation with 2, and a green intermediate is observed, which then slowly converts to sulfenate-ligated 5. This suggests that the mechanism of sulfur oxidation involves initial coordination of the oxo atom donor to the metal ion. Whether the green intermediate is an oxo atom donor adduct, Fe-O═I-Ph, or an Fe(V)═O remains to be determined.

Difructose anhydride (DFA) III acts on intestinal epithelial tight junctions and promotes calcium absorption through the paracellular pathway in dairy cows. This trial was done to investigate the effects of DFA III supplementation on passive IgG transfer and serum IgG concentration in calves. Twenty-four newborn Holstein male calves were grouped as 12 pairs, with each pair receiving a separate batch of pooled colostrum (PC) from the first 2 milkings. One calf from each pair was allocated to the treatment group (n=12) and received 18g of DFA III in each feeding; the other calf was assigned to the control group (n=12) and did not receive DFA III. All calves were fed 2 L of PC per feeding at 1, 10, and 24 h after birth. Prefeeding blood samples taken at 0 h, 10 h, 24 h, 36 h, 4 d, and 7 d were analyzed for serum IgG concentration. Apparent efficiency of IgG absorption in the treatment group was higher compared to that in the control group. Serum IgG concentration of calves in the treatment group was higher for all sampling time points except for 0 h of age. Mean serum IgG concentrations in the treatment and control groups at 36 h of age were 22.3 and 17.7 g/L, respectively. Serum IgG concentration at 36 h of age was positively related with the IgG concentration in the PC in both groups, and it was higher in the treatment group than in the control group at the same IgG concentration in the PC. These results indicate that absorption of ingested IgG by endocytosis as well as a nonselected concentration gradient process of the paracellular pathway of the intestinal epithelium could be enhanced by DFA III supplementation. Supplementation of DFA III in PC containing various IgG concentrations could improve IgG absorption as well as calf serum IgG concentration.

The degradation and recovery behavior of the device performance on GaN LEDs (light emitting diodes) irradiated by 2-MeV electrons and 70-MeV protons are studied. The reverse current increases after irradiation, while the capacitance decreases. The device performance degradation is proportional with the fluence. For electron irradiation, the fluence rate also has an impact on the degradation. A low fluence rate shows larger degradation compared to a high fluence rate due to heat impact in the bulk. DLTS measurements reveal the DX center in the substrate before and after irradiation, and the concentration of DX center increases with fluence. The radiation damage for protons is larger than that of electron irradiation, which is caused by the difference of mass and the possibility of nuclear collisions resulting in the formation of lattice defects. After irradiation, the diode performance recovers by thermal annealing.

We report electromigration techniques for the fabrication of planar-type tunnel junctions with ferromagnetic nanogap system. In these techniques, by monitoring the current passing through the devices, we are easily able to obtain the planar-type Ni-Vacuum-Ni tunnel junctions. In this paper, magnetoresistance (MR) properties of the planar-type Ni-based tunnel junctions formed by stepwise feedback-controlled electromigration (SFCE) and field-emission-induced electromigration (activation) are studied. We performed the SFCE method for Ni nanoconstrictions connecting asymmetrical butterfly-shape electrodes. Furthermore, the activation technique was applied to Ni nanogaps with separations of 15-45 nm. MR ratio of the devices formed by the SFCE exhibited approximately 4% at 16 K . On the other hand, the devices fabricated by the activation showed MR ratio of above 300% at 16 K. These results suggest that it is possible to fabricate planar-type ferromagnetic tunnel junctions with vacuum barriers by electromigration techniques.

This study was completed to determine the effects of potato pulp silage (PPS) as a diet supplement on the composition of milk fatty acids in grazing dairy cows in comparison to a barley grain supplement. Eight late lactation Holstein dairy cows were fed grazing based diets supplemented with 150 g/kg of PPS (‘PPS’) as a substitute for barley (‘barley’), and grazed on 4.3 ha swards, mainly containing orchard grass, for 56 days. Total dry matter (DM) and pasture DM intake and milk yields, as well as milk composition, did not differ between treatments. The linolenic acid intake did not differ (329 g/day vs. 323 g/day DM). The trans11C18:1vaccenic acid (VA) concentration in blood was higher in cows fed PPS (2.4 g/100 g FA) compared to those fed barley (1.9 g/100 g FA). There were no differences between treatments in the cis9trans11conjugated linoleic acid (CLA) concentration in blood. The short-chain and medium-chain fatty acids in milk also did not differ between treatments. The VA concentration in milk was increased in cows fed PPS (2.32 g/100 g FA) compared to those fed barley (1.84 g/100 g FA), and CLA was higher in cows fed PPS (1.25 g/100 g FA) than those fed barley (0.95 g/100 g FA). Milk CLA concentration was positively correlated to blood VA concentration. Results suggest that an increase in milk CLA concentration is related to an increase of the VA concentration in blood by Δ9-desaturase in mammary glands in the PPS fed compared to barley fed groups.

Variations in conjugated linoleic acid (CLA) concentrations in Holstein dairy cows milk, depending on feeding systems in different seasons was investigated. Milk samples were collected from Holstein dairy cows, which either grazed for whole days (WG), only daylight hours (TG), or were offered a total mixed ration (TMR) and experienced no grazing (NG), from April to December of 2005. In April, November and December, the cows in TG and WG treatments received grass silage and some concentrate, while from May to October, the cows grazed on temperate pasture. The cows in NG treatment received the TMR throughout the season. The major fatty acid obtained in the pastures was linolenic acid. There was no significant difference in the pasture's linolenic acid concentrations from May to September, but there was a significant decrease in October. However, the linolenic acid concentrations obtained in the pasture were always much higher than those obtained from the TMR. Linoleic acid was also the major fatty acid in the TMR, but these concentrations were higher in the TMR than in the pasture. There was no significant difference in milk cis9trans11CLA (c9t11CLA) concentrations between the three feeding systems while the cows were fed on conserved pasture in April, November and December. Although c9t11CLA concentrations were lower in the TMR, it was found that the cows which grazed in fresh pasture experienced significantly higher concentrations of c9t11CLA in their milk than those which received only TMR. It was also found that cows in the WG treatment experienced higher c9t11CLA concentrations than those in the TG treatment. In the WG and TG treatments, c9t11CLA concentrations were highest in June, after which, they gradually decreased (p 0.05) with season. Overall, trans11C18:1 and c9t11CLA were greatly influenced by season, with higher variation in the WG treatment than in the TG treatment and no variation in the NG treatment. (Key Words : Feeding System, Seasonal Change, Conjugated Linoleic Acid, Milk Fatty Acids Composition)

The degradation and recovery behavior of device performance on GaAlAs LEDs (Light emitting diodes) irradiated by 2-MeV electrons and 70-MeV protons are investigated. The reverse current increases after irradiation, while the capacitance decreases. The device performance degradation is proportional with fluence. For electron irradiation, fluence rate is also effective for degradation. Low fluence rate shows more large degradation compared to high fluence rate resulting from heat impact in bulk. DLTS measurement reveals the DX center in epitaxial substrate, and this spectrum increases with fluence. The radiation damage of proton is larger than that of electron irradiation, which is caused by the difference of mass and possibility of nuclear collision for the formation of lattice defects. After irradiation, the device performance recovers by thermal annealing.

Ensiling of the by-product of daikon or Oriental radish (Raphanus sativus), a popular root vegetable in East Asia, as a viable preservation method and potential animal feed resource was investigated. Two separate experiments were carried out: the first involved a study of the chemical and some intrinsic pre-ensiling characteristics of daikon as a prelude to ensiling of daikon by-product. The high moisture content of daikon by-product was adjusted first with wheat straw as a sole absorbent and inoculated with or without Lactobacillus plantarum (LP), a lactic acid culture, the monitoring of fermentation products and microbial development in the silages with days in ensilage and the study of the aerobic stability after 6 days. The second investigated the use of dried beet pulp, bean stalks and husks and wheat bran as alternate in-silo effluent absorbents followed by silage intake and preference test with sheep. While ensiling daikon with or without LP produced well fermented silage, a major limitation is the high effluent production and consequent nutrient losses; incorporation with dry materials is sine qua non for its preservation by ensilage. Silages were stable after 4 days of aerobic exposure but began to deteriorate after 5 days especially with daikon added with the wheat straw absorbent. Wheat straw retained effluent most followed by bean stalks and husks, and dried beet pulp in that order, while wheat bran showed poor effluent retention capacity. Dried beet pulp/daikon mixture silage was best in terms of feed intake and preference.

Three Holstein steers fitted with ruminal and duodenal cannulae were fed grass silage-based diets supplemented with potato pulp silage as a substitute for rolled corn at levels of 0%, 50% and 100% on a DM basis in a 3x3 Latin square design to investigate the effect of potato pulp silage on nitrogen (N) utilization in ruminants. Organic matter (OM) intake, and rumen and total tract digestibilities did not differ among treatment diets. Rumen and post-rumen starch digestibilities were similar among treatments, although starch intake decreased (p 0.05) in ruminal N utilization and non-ammonia N supply to the duodenum of steers fed grass silage supplemented with potato pulp silage as a substitute for rolled corn. There were no treatment differences (p>0.05) in rumen pH, volatile fatty acid (VFA) concentration or the molar percentages of acetate and propionate. The ammonia-N concentration in rumen fluid tended to decrease (p

The temperature control system of the large-size plasma grid has been developed to realize the long pulse production of high-current negative ions for JT-60SA. By using this prototype system for the JT-60SA ion source, 15 A negative ions has been sustained for 100 s for the first time, which is three times longer than that obtained in JT-60U. In this system, a high-temperature fluorinated fluid with a high boiling point of 270 degree Celsius is circulated in the cooling channels of the plasma grids (PG) where a cesium (Cs) coverage is formed to enhance the negative ion production. Because the PG temperature control had been applied to only 10% of the extraction area previously, the prototype PG with the full extraction area (110 cm × 45 cm) was developed to increase the negative ion current in this time. In the preliminary results of long pulse productions of high-current negative ions at a Cs conditioning phase, the negative ion production was gradually degraded in the last half of 100 s pulse where the temperature of an arc chamber wall was not saturated. From the spectroscopic measurements, it was found that the Cs flux released from the wall might affect to the negative ion production, which implied the wall temperature should be kept low to control the Cs flux to the PG for the long-pulse high-current production. The obtained results of long-pulse production and the PG temperature control method contributes the design of the ITER ion source.

A 3x3 factorial design experiment was conducted to investigate the effect of temperature and duration of storage on the fermentation quality of potato pulp ensiled with two fungal inoculants under laboratory conditions. The inoculants, Rhizopus oryzae (R) and Amylomyces rouxii (A) were each added to potato pulp material to contain at least 1×10 6 CFU/g fresh matter, and silages without additives served as controls. The silages were stored under three temperature regimes; 4, 12 and 25°C. Three silos per treatment from every temperature regime were opened on days 7, 24 and 40 days after ensiling to investigate treatment effects on fermentation quality, starch and sugar concentrations. Increase in temperature and duration of storage had a positive significant effect (p 0.05) on the fermentation quality of the silages. Sugar concentration in the silages decreased with increase in temperature (p

The present objective of the 1 MeV electrostatic accelerator R&D for the ITER NB system is the acceleration of ampere class negative ion beams at the required current density (200 A m−2) up to the beam energy of 1 MeV. To produce such high current density H− ions, the KAMABOKO negative ion source was operated under high power arc discharge (≤40 kW) and with Caesium seeding for enhancement of the negative ion surface production. The H− ion beams of 146 A m−2 (total ion current: 0.2 A) have been obtained stably at the beam energy of 836 keV (pulse length: ≥0.2 s). The pulse length was limited due to the power density of the beams, which is more than twice as high as those of the existing negative ion based NB systems (JT-60U and LHD). A preliminary measurement of beam optics showed a beamlet divergence of ≈5 mrad even in the beams of such high power density. The Bremsstrahlung generation as a consequence of electron acceleration was estimated. A discussion then follows for photoelectron production and possible breakdowns in insulators for the acceleration of higher current negative ions.

The 500 keV negative-ion based neutral beam injector for JT-60U started operations in 1996. The availability of the negative ion based neutral beam injection system has been improved gradually by modifying the ion source and optimizing its operation parameters. Recently, the extension of the pulse duration up to 30 s has been intended to study quasi-steady state plasma on JT-60U. The most serious issue is to reduce the heat load on the grids for long pulse operation. Two modifications have been proposed to reduce the heat load. One is to suppress the spread of beamlet-bundle which may be caused by beamlet–beamlet interaction in the multi-aperture grid due to the space charge force. Indeed, the investigation of the beam deflection, which was measured by the infrared camera on the target plate set 3.5 m away from the grid, indicates that the spread of beamlet-bundle is in proportion to the current density. Field-shaping plates were attached on the extraction grid to modify the local electric field. The plate thickness was optimized to steer the beamlet deflection. The other is to reduce the stripping loss, where the electron of the negative ion beam is stripped and accelerated in the accelerator and then collides with the grids. The ion source was modified to reduce the pressure in the accelerator column to suppress the beam-ion stripping loss. To date, long pulse injection of 19 s of 1.5–1.6 MW at a high energy beam of 360 keV, 9–10 A for D− has been obtained by one ion source with these modifications.

In the negative ion based neutral beam injector (N-NBI) for JT-60U, an extension of the pulse duration up to 30 s has been intended to study quasi-steady state plasmas, where the NBI pulse duration is significantly longer than the plasma current diffusion time. Achieving long pulse injection requires a reduction of the heat load on the grids of the ion source. The ion source was modified to reduce the pressure within the grid structure by increasing the vacuum conductance of the acceleration grids. The acceleration efficiency was improved from 0.74 to 0.79. The heat load of the grounded grid, which was the main heat load of the acceleration grids, decreased from 9.2 to 7.0% at a constant arc chamber pressure of 0.3 Pa. These improvements seemed to be caused by the reduction of beam ion stripping loss. Up to now, a long pulse injection of 17 s at the power of 1.6 MW with beam energy of 366 keV was obtained by using one ion source. The temperature rise of the cooling water from the grounded grid saturated at less than 35 °C during operation, so the heat load of the grid is significantly reduced for steady state operation at this power level.

The origin of the beam non-uniformity, that is one of the key issues in JT-60 negative ion sources, was experimentally examined by measuring correlations between the intensity of the H− ion beam and plasma parameters, such as an electron temperature and plasma density in the JAERI 10 A negative ion source. The ion source was operated without cesium. Although a uniform filter field was applied, the electron temperature near plasma grid (PG) was higher than 1 eV in the upper half region of the longitudinal direction, where the spatial beam intensity decreased rapidly. This indicates that the beam non-uniformity is caused by a higher electron temperature than 1 eV, namely, by a leakage of the high-energy electrons toward the PG. To investigate the path of high-energy electrons leaking into the PG, a metal plate of 50 mm × 50 mm was placed in the plasma. By placing the plate in a weak magnetic field of

R&D pertaining to a 1 MeV accelerator and a large negative ion source has been carried out at the Japan Atomic Energy Research Institute for the ITER neutral beam system. The R&D is, at present, progressing towards: (1) 1 MeV acceleration of H− ion beams at the ITER relevant current density of 200 A m−2 and (2) improvement of uniform negative ion production over wide extraction area in large negative ion sources. Recently, H− ion beams of 1 MeV and 140 mA level have been generated with a substantial beam current density (100 A m−2). In the uniformity study, it was clarified that the electron temperature in the ion extraction region was locally high (>1 eV), which resulted in the destruction of negative ions at a high reaction rate. Interception of fast electrons leaking through a transverse magnetic field called 'magnetic filter' has been found to be effective in lowering the local electron temperature, followed by an improvement of negative ion beam profile.

Effect of addition of two bacteria inoculants at ensiling on the fermentation quality, change in nutrient composition and the nutritive value of potato pulp silage (PPS) was investigated. Two separate experiments were carried out on a laboratory scale using two bacterial inoculants: Lactobacillus rhamnosus alone (L), Rhizopus oryzae alone (R) and a combined application of the two inoculants (R + L). The first involved a study on the time course changes in fermentation characteristics and nutrient composition of the silage, while the second focused on the chemical composition after 50 days of ensilage. The nutritive value of PPS was studied in vivo digestibility trial using sheep in a 4 × 4 Latin square design. In both investigations, R decreased (P 0.05) on the digestibility of PPS. The results show that potato pulp can ensile well with or without bacterial inoculants. The high nutritive value of PPS (about 720 g/kg DM Abbreviations: ADF, acid detergent fiber; aNDF, neutral detergent fiber; BW, body weight; CFU, colony forming units; CP, crude protein; DE, digestible energy; DM, dry matter; EE, ether extract; GE, gross energy; L, Lactobacillus rhamnosusalone; LDH, lactate dehydrogenase; MJ/kg DM, mega joules per kilogram dry matter; NARO, National Agricultural Research Organization, (Japan); OM, organic matter; PPS, potato pulp silage; R, Rhizopus oryzaealone; R + L, Rhizopus oryzaeand Lactobacillus rhamnosuscombined inoculant; SEM, standard error of the mean; SBM, soybean meal; TDN, total digestible nutrients; VFA, volatile fatty acid

The ITER NB System consists of two injectors each delivering 16.7 MW to the plasma in the form of neutral deuterium atoms accelerated at 1 MeV. Each injector has a single negative ion source connected to a 1 MV electrostatic accelerator. The accelerated negative ions pass through a neutraliser, then an electrostatic deflection system, where residual ions, exiting after neutralisation, are dumped. The neutral part of the beam continues to the torus through a duct connecting to the torus vessel. The 1 MV bushing is an insulated cylindrical, feedthrough (about 2 m in diameter and 2.5 m in height), which forms the physical boundary between the gas-insulated transmission line and the torus primary vacuum. An innovative design has been developed fulfilling all the requirements, including 1 MV class insulation in vacuum for a large number of services, vacuum compatibility, operation under neutrons and gamma radiation, safety requirements for pressure containment. In particular, the design allows a nitrogen pressurised guard volume that prevents any leakage of the external insulation gas (sulphur hexaflouride, potentially damaging for platinum/palladium catalysts of the tritium recovery system) inside the torus primary vacuum, and relieves the alumina insulator from substantial structural functions. The article describes the design, the selection of the materials and the mechanical analyses. To validate the design a reduced scale prototype, including all the relevant mechanical and electrical features of the bushing insulator, has been successfully manufactured and tested. The article reports an overview of this development.

The negative-ion based neutral beam injection system developed by JAERI for JT-60U has been intended to generate a 500 keV and 10 MW beam for 10 seconds with two ion sources. Technical efforts to d...

Two pilot facilities of advanced negative-ion-based neutral beam injection heating system have been working successfully on the JT-60U tokamak and the LHD heliotron in Japan. These were the first applications of negative-ion technology to the production of high current neutral beam for plasma heating as well as current drive. High energy deuterium beam of 400 keV (5.8 MW) was injected in JT-60U for efficient current drive, and high power hydrogen beam of 9.0 MW (160 keV) was injected in LHD producing high performance plasmas. These results demonstrate the feasibility of negative ion beam system for future fusion reactors such as ITER.

High energy accelerator and high current ion source development have been carried out at JAERI for negative-ion based neutral beam (N-NB) systems of JT-60U and ITER. One of R&D issues on the ITER prototype 5-staged electrostatic accelerator was voltage holding capability of the accelerator insulator column. By installing a stress ring, which reduces electric field concentration at the triple junction (interface of metal flange, insulator, and vacuum), 300 kV is held at each stage instead of rated voltage of 200 kV. At present the accelerator insulator column sustains 900 kV stably with the rings in all five stages. In the JT-60U N-NB system, a beamlet deflection by distorted electric field was found at the bottom of the extractor. Correcting the distorted field, reduction in beam divergence was confirmed for the overall beam. As the result, the heat load on the NB port limiter of JT-60U, located about 20 m away from the accelerator, was reduced to less than a half of the previous value before the correction. Consequently, we have succeeded in 10 s continuous injection of H 0 beam with the NB power of 2.6 MW at 355 keV.

The operation of an accelerator at low pressure is an essential requirement to reduce the stripping loss of negative ions, which, in turn, results in high efficiency of the neutral beam systems. For this purpose, a vacuum insulated beam source (VIBS) has been developed at Japan Atomic Energy Research Institute, which reduces the gas pressure in the accelerator by enhanced gas conductance through the accelerator. The VIBS achieves a high voltage insulation of 1 MV by immersing the whole structure of the accelerator in vacuum with a long (~1.8 m) insulation distance. Results of the voltage holding test using a long vacuum gap of 1.8 m indicate that a transition from vacuum discharge to gas discharge occurs at around 0.2 Pa m in the long vacuum gap. So far, the VIBS succeeded in accelerating a 20 mA (H−) beam up to 970 keV for 1 s. It has been demonstrated that the high voltage holding capability of the 1 MV bushing surrounding the VIBS accelerator could be drastically improved by installing new large stress rings that reduces the electric field concentration at the triple junction. After implementing this change, the VIBS sustained 1 MV stably for more than 1200 s. Acceleration of ampere class H− beams at high current density is to be started soon to demonstrate ITER relevant beam optics. The operation of a negative ion source at low pressure is also essential to reduce the stripping loss. However, it was not very easy to attain high current density H− ions at low pressure, since the destruction cross-section of the negative ion becomes large if the electron temperature is >1 eV in low pressure discharge. Using a strong magnetic filter to lower the electron temperature, and introducing higher arc discharge power to compensate for the reduction of plasma density through the filter, an H− ion beam of 310 A m−2 was extracted at a very low pressure of 0.1 Pa. This satisfies the ITER requirement of current density at one-third of the ITER design pressure (0.3 Pa).

The injection performance of the negative-ion based NBI (N-NBI) system for JT-60U has been improved by correcting beamlet deflection and improving spatial uniformity of negative ion production. Beamlet deflection at the peripheral region of the grid segment due to the distorted electric field at the bottom of the extractor has been observed. This was corrected by modifying the surface geometry at the extractor to form a flat electric field. Moreover, beamlet deflection due to beamlet–beamlet repulsion caused by space charge was also compensated for by extruding the edge of the bottom extractor. This resulted in a reduction of the heat loading on the NBI port limiter. As a result of the improvement above, continuous injection of a 2.6 MW H0 beam at 355 keV has been achieved for 10 s. Thus, long pulse injection up to the nominal pulse duration of JT-60U was demonstrated. This has opened up the prospect of long pulse operation of the negative-ion based NBI system for a steady-state tokamak reactor. So far, a maximum injection power of 5.8 MW at 400 keV, with a deuterium beam, and 6.2 MW at 381 keV, with a hydrogen beam, have been achieved in the JT-60U N-NBI. Uniformity of negative ion production was improved by tuning the filament emission current so as to direct more arc power into the region where less negative ion current was extracted.

Japanese contributions to ITER engineering design activities are presented, together with an introduction of the objectives and design of the ITER, whose program has been carried out through intern...

A vacuum insulated beam source (VIBS), where all the components including the negative ion source and the acceleration grids are immersed in the vacuum, has been designed at Japan Atomic Energy Research Institute. The beam source is characterized by high gas flow conductance that reduces stripping losses of negative ions in the accelerator and improves the acceleration efficiency. The gas flow in VIBS was calculated using a 3-D Monte-Carlo code. At a typical operating pressure of 0.3 Pa in the negative ion source, the stripping loss of D − ions in VIBS is about 23%, which is about half of stripping loss in the gas insulated beam source (GIBS) that was designed in the ITER-FDR design. The acceleration efficiency is improved from 84 to 94%. To enhance the acceleration efficiency further, the possibility for reducing the operating pressure was experimentally studied. It was found the negative ion production in the KAMABOKO source adopted for ITER is dominated by surface production, therefore, the operating pressure can be reduced by improving plasma confinement. It is predicted that the operating pressure in KAMABOKO source can be reduced to 0.15 Pa, where the stripping loss and the acceleration efficiency in VIBS are improved to be 13 and 97%, respectively.

The neutral beam (NB) system in ITER-FEAT provides heating and current drive (H&CD) by two NB injectors, each delivering 16.7 MW of D 0 beam to the plasma at 1 MeV. The NB system retains the basic concept of the ITER 1998 design, but there are certain modifications that will be described: the beam transmission is improved by a four beam channel design of the neutralizer and the RID. Also the layout of the NB injector integrated in ITER allows both on- and off-axis current drive. The improved performance of the NB system is discussed from the system efficiency and the current drive capability points of view.

Heat loading of acceleration grids has been investigated using a JAERI 400 keV negative hydrogen ion source, which has a three-stage multiaperture accelerator. To investigate the effect of beamlet steering on the heat loading, the apertures in the grounded grid were displaced up to 5 mm. The steering angle increased linearly with the displacement distance of the grid. The obtained steering angle was 7.5 mrad at the displacement distance of 5 mm. It was confirmed that the steering angle agrees well with the thin lens theory. Degradation of beam optics due to the steering was not observed. The heat load of the grounded grid was scarcely changed up to the displacement distance of 2 mm and then increased from 2.5% to 8% of the total input power when the grid was displaced from 2.5 to 5 mm. Heat loads of the other unsteered grids were not changed.

Critical heat flux (CHF) tests on a new type of rectangular cooling tube, ‘saw-toothed fin duct, SFD’ for high heat flux components were performed under one-sided heating conditions. The tube has internal triangle fins at the heating side to enhance the CHF characteristics. Hydraulic conditions were as follows: axial flow velocity ranged from 2 to 12 m/s. Local pressure at the center of the test sample was 1 MPa and inlet water temperature was 21–25 °C. In the present work, SFD, which has a fin height of 3.46 mm and an installation angle of the fin of 70°, results in the highest CHF of 43 MW/m2 at the axial flow velocity of 10 m/s. This value is 1.3 times higher than that obtained with a Hypervapotron.

In the engineering design of a negative-ion beam source for a high-power neutral beam injection (NBI) system, one of the most important issues is thermo-mechanical design of acceleration grids for producing several tens of MW ion beams. An acceleration grid for the international thermonuclear experimental reactor–neutral beam injection (ITER–NBI) system will be subjected to the heat loading as high as 1.5 MW. In the present paper, thermo-mechanical characteristics of the acceleration grid for the ITER–NBI system were analyzed. Numerical simulation indicated that maximum aperture-axis displacement of the acceleration grid due to thermal expansion would be about 0.7 mm for the heat loading of 1.5 MW. From the thin lens theory of beam optics, beamlet deflection angle by the aperture-axis displacement was estimated to be about 2 mrad, which is within the requirement of the engineering design of the ITER–NBI system. Numerical simulation also indicated that no melting on the acceleration grid would occur for a heat loading of 1.5 MW, while local plastic deformation would happen. To avoid the plastic deformation, it is necessary to reduce the heat loading onto the acceleration grid to less than 1 MW.

Neutronics of the neutral beam (NB) injector for international thermonuclear experimental reactors (ITER) was analyzed by two- and three-dimension (3-D) codes, and their results were then compared. The neutron flux on the beam line axis obtained by the 2-D code agrees with that by the 3-D code within 30%. The shutdown dose rate around the NB injector was estimated by the 2-D model developed by taking into consideration both the plasma operation pattern and the scenario. The dose rate at 106 s after the shutdown around the NB injector was estimated to be 40 μSv/h, which allows for hands-on maintenance during the shutdown period.

The article reports on the progress made by the ITER European Home Team in strong interaction with the ITER Joint Central Team and the Japan Atomic Energy Research Institute regarding several key aspects of the beam source for the ITER injectors: (1) Integration of the SINGAP accelerator into the ITER injector design. This is a substantially simpler concept than the multiaperture, multigap (MAMuG) accelerator of the ITER NBI reference design that has the potential for significant cost savings and that avoids some of the weaknesses of the reference design such as the need for intermediate high voltage potentials from the high voltage power supply and pressurized gas insulation. (2) High energy negative ion acceleration using a SINGAP accelerator. (3) Long pulse (i.e. >1000 s) negative ion source operation in deuterium. (4) RF source development, which could reduce the scheduled maintenance of the ITER injectors (as it uses no filaments), and simplify the transmission line and the auxiliary power supplies for the ion source.

Intense negative ion source producing multimegawatt hydrogen/deuterium negative ion beams has been developed for the neutral beam injector (NBI) in TOKAMAK thermonuclear fusion machines. Negative ions are produced in a cesium seeded multi-cusp plasma generator via volume and surface processes, and accelerated with a multistage electrostatic accelerator. The negative ion source for JT-60U has produced 18.5 A/360 keV (6.7 MW) H− and 14.3 A/380 keV (5.4 MW) D− ion beams at average current densities of 11 mA/cm2 (H−) and 8.5 mA/cm2 (D−). A high energy negative ion source has been developed for the next generation TOKAMAK such as the International Thermonuclear Experimental Reactor (ITER). The source has demonstrated to accelerate negative ions up to 1 MeV, the energy required for ITER. Higher negative ion current density of more than 20 mA/cm2 was obtained in the ITER concept sources. It was confirmed that the consumption rate of cesium is small enough to operate the source for a half year in ITER-NBI without maintenance.

The surface of concrete structures is subject to abrasion when they are constructed in sea water where ice movement is active. Abrasion occurs due to the friction force between ice sheets and the structure caused by the ice force working on the structure.Over the past ten years we have been conducting experiments with many types of concrete and their possible coating materials to find their characteristics of abrasion due to movements of ice sheets. In this experiment we calculated the abrasion rates (average amount of abrasion per 1km movement of ice sheets) of various kinds of stone needed to estimate the abrasion amount due to movements of ice sheets which contain sand particles or not, and we also clarified the mechanism of abrasion.

Neutral beam injection has been the most successful scheme used to heat magnetically confined plasmas studied in controlled nuclear fusion research, and neutral beams are a candidate to heat to ignition the International Tokamak Experimental Reactor (ITER). This article describes the system which is presently being designed in Europe, Japan, and Russia, with coordination by the Joint Central Team of ITER at Naka, Japan. The proposed system consists of three negative ion based neutral injectors, delivering a total of 50 MW of 1 MeV D0 to the ITER plasma for pulse length of ≳1000 s. The proposed injectors each use a single caesiated volume arc discharge negative ion source, and a multigrid, multiaperture accelerator, to produce about 40 A of 1 MeV D−. This will be neutralized in a subdivided gas neutralizer, which has a conversion efficiency of about 60%. The charged fraction of the beam emerging from the neutralizer is dumped onto the water‐cooled surfaces making up the electrostatic residual ion dump. A w...

Development of an electrostatic accelerator for 1 MeV, 1 ampere class H− ion beams has been carried out as a Proof-of-Principle (PoP) of high current accelerators required in neutral beam system of fusion reactors such as ITER. A unique feature of such fusion oriented accelerators is to utilize vacuum insulation not only inside but also outside of the accelerator for high voltage insulation, since conventional gas insulation is not applicable due to excess radiation induced conductivity in the gas. The PoP accelerator is surrounded by an insulator stack as a vacuum boundary with a vacuum gap of 50 mm all around the accelerator. One of the key technologies to achieve insulation of MV voltage was reduction of electric field strength at triple junction of the insulator (made of FRP, fiber reinforced plastic) stack. By lowering the stress to 1.7 kV/mm, the accelerator sustained 1 MV stably for more than 2 hours. By tuning the ion source with/without cesium under stable accelerator operation, the PoP accelerat...