Three-dimensional impurity transport modeling of neon-seeded and nitrogen-seeded LHD plasmas

Modeling of impurity-seeded plasma in Large Helical Device is presented for the first time by using the three-dimensional transport code EMC3-EIRENE. High and low recycling coefficients for impurity ions are assumed to include low and high absorption rates on wall surfaces due to low and high chemical activity of neon and nitrogen, respectively. Radiation power measured by two bolometer systems and particle flux measured by divertor probes installed in multiple toroidal sections are utilized to determine impurity amount in the plasma. The toroidal uniformity and the non-uniformity of a divertor flux reduction observed experimentally for neon and nitrogen seeding, respectively, are reproduced by the model. Validations by measurements and deviations between the model and the experiment are discussed

Delayed neuronal cell death in brainstem after transient brainstem ischemia in gerbils

<p>Abstract</p> <p>Background</p> <p>Because of the lack of reproducible brainstem ischemia models in rodents, the temporal profile of ischemic lesions in the brainstem after transient brainstem ischemia has not been evaluated intensively. Previously, we produced a reproducible brainstem ischemia model of Mongolian gerbils. Here, we showed the temporal profile of ischemic lesions after transient brainstem ischemia.</p> <p>Results</p> <p>Brainstem ischemia was produced by occlusion of the bilateral vertebral arteries just before their entry into the transverse foramina of the cervical vertebrae of Mongolian gerbils. Animals were subjected to brainstem ischemia for 15 min, and then reperfused for 0 d (just after ischemia), 1 d, 3 d and 7 d (n = 4 in each group). Sham-operated animals (n = 4) were used as control. After deep anesthesia, the gerbils were perfused with fixative for immunohistochemical investigation. Ischemic lesions were detected by immunostaining for microtubule-associated protein 2 (MAP2). Just after 15-min brainstem ischemia, ischemic lesions were detected in the lateral vestibular nucleus and the ventral part of the spinal trigeminal nucleus, and these ischemic lesions disappeared one day after reperfusion in all animals examined. However, 3 days and 7 days after reperfusion, ischemic lesions appeared again and clusters of ionized calcium-binding adapter molecule-1(IBA-1)-positive cells were detected in the same areas in all animals.</p> <p>Conclusion</p> <p>These results suggest that delayed neuronal cell death took place in the brainstem after transient brainstem ischemia in gerbils.</p

Effects of single therapeutic doses of promethazine, fexofenadine and olopatadine on psychomotor function and histamine-induced wheal- and flare-responses: a randomized double-blind, placebo-controlled study in healthy volunteers

Since most first-generation antihistamines have undesirable sedative effects on the central nervous systems (CNS), newer (second-generation) antihistamines have been developed to improve patients’ quality of life. However, there are few reports that directly compare the antihistaminic efficacy and impairment of psychomotor functions. We designed a double-blind, placebo controlled, crossover study to concurrently compare the clinical effectiveness of promethazine, a first-generation antihistamine, and fexofenadine and olopatadine, second-generation antihistamines, by measuring their potency as peripheral inhibitors of histamine-induced wheal and flare. Further, we investigated their sedative effects on the CNS using a battery of psychomotor tests. When single therapeutic doses of fexofenadine (60 mg), olopatadine (5 mg) and promethazine (25 mg) were given in a double-blind manner to 24 healthy volunteers, all antihistamines produced a significant reduction in the wheal and flare responses induced by histamine. In the comparison among antihistamines, olopatadine showed a rapid inhibitory effect compared with fexofenadine and promethazine, and had a potent effect compared with promethazine. In a battery of psychomotor assessments using critical flicker fusion, choice reaction time, compensatory tracking, rapid visual information processing and a line analogue rating scale as a subjective assessment of sedation, promethazine significantly impaired psychomotor function. Fexofenadine and olopatadine had no significant effect in any of the psychomotor tests. Promethazine, fexofenadine and olopatadine did not affect behavioral activity, as measured by wrist actigraphy. These results suggest that olopatadine at a therapeutic dose has greater antihistaminergic activity than promethazine, and olopatadine and fexofenadine did not cause cognitive or psychomotor impairment

Overview of transport and MHD stability study: focusing on the impact of magnetic field topology in the Large Helical Device

The progress in the understanding of the physics and the concurrent parameter extension in the large helical device since the last IAEA-FEC, in 2012 (Kaneko O et al 2013 Nucl. Fusion 53 095024), is reviewed. Plasma with high ion and electron temperatures (Ti(0) ~ Te(0) ~ 6 keV) with simultaneous ion and electron internal transport barriers is obtained by controlling recycling and heating deposition. A sign flip of the nondiffusive term of impurity/momentum transport (residual stress and convection flow) is observed, which is associated with the formation of a transport barrier. The impact of the topology of three-dimensional magnetic fields (stochastic magnetic fields and magnetic islands) on heat momentum, particle/impurity transport and magnetohydrodynamic stability is also discussed. In the steady state operation, a 48 min discharge with a line-averaged electron density of 1 × 1019 m−3 and with high electron and ion temperatures (Ti(0) ~ Te(0) ~ 2 keV), resulting in 3.36 GJ of input energy, is achieved

Recycling of calcined carbonated cement pastes as cementitious materials: Proposed CCUS technology for calcium looping

In this study, calcined carbonated hydrated cement pastes (HCPs) were used to partially replace ordinary Portland cement (OPC) as a cementitious material. Calcined carbonated HCP can be derived from carbonated HCP after the release of CO2 for the carbon capture, utilization, and storage (CCUS). Calcined carbonated HCP was produced by calcining carbonated HCP at 1000 degrees C, also used in calcium looping. The crystal phase compositions of the HCP, carbonated HCP, and calcined carbonated HCP were identified. Various hardening and microstructural tests on the composite cement paste mixtures blended with calcined carbonated HCP were performed. The initial results showed that the HCP could sequester CO2, forming various calcium carbonates. After carbonated HCP calcination, the main nanocrystalline phases of calcium silicate hydrate (C-S-H) and calcium carbonate decomposed, forming lime and wollastonite. The 28-day compressive strength of the calcined carbonated HCP-OPC mixtures increased with the replacement ratio up to 20%, owing to the filler effect of wollastonite. The microstructural analysis revealed that the portlandite, C-S-H, and monocarboaluminate phases were formed after hydration. Finally, by recycling demolition waste, this study proposed a technology roadmap for CCUS to achieve this goal, and a life cycle assessment was conducted to evaluate and compare the environmental impacts of producing 1 t of calcined carbonated HCP-OPC mixtures and plain OPC paste

Prediction of the drying shrinkage of alkali-activated materials using artificial neural networks

Alkali-activated materials (AAMs) are qualitatively and quantitatively evaluated with an emphasis on the ultimate drying shrinkage. We systematically evaluated AAMs based on the mix design and curing conditions, utilizing a total of 452 AAM mixtures extracted from 44 papers. Finally, a predictive model for the ultimate drying shrinkage of AAMs was constructed using an artificial neural network (ANN) with high accuracy, in which the reactivity of binder, geopolymer paste volume, liquid-to-binder ratio, alkali activator modulus, aggregate volumetric ratio, curing temperature, relative humidity and specimen size were set as inputs. This model shows great generality by compiling various AAM mixtures and is easy-handling without preparation of samples for acquiring specific properties. Moreover, the efficiency of three commonly used models for predicting the drying shrinkage-the Bazant-Baweja model, Gardner and Lockman model, and multi-linear regression model-were evaluated and compared to the proposed ANN model, revealing a better prediction performance of ANN model. This study will advance the understanding of the drying shrinkage behaviors of AAMs and provide practical guidelines for designing AAM mixtures with high durability