Transport Properties of Steam Curing Concrete Using Mineral Admixtures

Steam curing has been used widely in the precast concrete industry. However, investigations on steam curing concrete focused mainly on their strength development. Research on durability of steam curing concrete, particularly on mixes using mineral admixtures, is somewhat limited. In this study, transport properties and mechanical properties of concretes using mineral admixtures under different steam curing conditions were measured. Normal Portland cement, high early strength Portland cement, ground granulated blast-furnace slag and fly ash were used. Steam curing conditions were varied by changing the preliminary curing time, temperature drop rate and curing method after steam curing. Transport properties, such as oxygen gas diffusion coefficient and water diffusion coefficient were measured. Moreover, mechanical properties, such as compressive strength, static elastic modulus and dynamic elastic modulus were measured. From the experimental result, the degree of the influence that the differences in steam curing conditions give to transport properties varies according to the types of binder. It was confirmed that transport properties might decrease remarkably in comparison with the case of a standard steam curing condition

Characterization of the chromosomal inversion associated with the Koa mutation in the mouse revealed the cause of skeletal abnormalities

<p>Abstract</p> <p>Background</p> <p>Koala (<it>Koa</it>) is a dominant mutation in mice causing bushy muzzle and pinna, and is associated with a chromosomal inversion on the distal half of chromosome 15. To identify the gene responsible for the <it>Koa </it>phenotypes, we investigated phenotypes of <it>Koa </it>homozygous mice and determined the breakpoints of the inversion with a genetic method using recombination between two different chromosomal inversions.</p> <p>Results</p> <p>Skeletal preparation of <it>Koa </it>homozygotes showed marked deformity of the ribs and a wider skull with extended zygomatic arches, in addition to a general reduction in the lengths of long bones. They also had open eyelids at birth caused by a defect in the extension of eyelid anlagen during the embryonic stages. The proximal and distal breakpoints of the <it>Koa </it>inversion were determined to be 0.8-Mb distal to the <it>Trsps1 </it>gene and to 0.1-Mb distal to the <it>Hoxc4 </it>gene, respectively, as previously reported. The phenotypes of mice with the recombinant inverted chromosomes revealed the localization of the gene responsible the <it>Koa </it>phenotype in the vicinity of the proximal recombinant breakpoint. Expression of the <it>Trsps1 </it>gene in this region was significantly reduced in the <it>Koa </it>homozygous and heterozygous embryos.</p> <p>Conclusion</p> <p>While no gene was disrupted by the chromosomal inversion, an association between the <it>Koa </it>phenotype and the proximal recombinant breakpoint, phenotypic similarities with <it>Trps1</it>-deficient mice or human patients with <it>TRSP1 </it>mutations, and the reduced expression of the <it>Trsps1 </it>gene in <it>Koa </it>mice, indicated that the phenotypes of the <it>Koa </it>mice are caused by the altered expression of the <it>Trps1 </it>gene.</p

Astrocytic gliomas: MRI and pathological grade.

The relationship between MR configuration and pathological grade was studied in 41 histologically verified supratentorial astrocytic gliomas with a 0.5T superconductive MR system. The gliomas included 13 low-grade astrocytomas (LGAs), 14 anaplastic astrocytomas (AAs) and 14 glioblastoma multiformes (GBMs). MRI configurations were classified into nine criteria which were scored and statistically analyzed. The mean values of LGAs, AAs and GBMs were 0.45 +/- 0.31, 1.18 +/- 0.20 and 1.47 +/- 0.22. In each grade, MRI score increased as pathological grades increased (p &#60; 0.01-0.001). LGAs had significantly lower values than AAs in five of the nine criteria (55.6%); heterogeneity, cyst or necrosis, edema or mass effect, border definition, and the degree of contrast enhancement, and lower values than GBMs in eight criteria (88.9%) except for hemorrhage. Three criteria (33.3%), heterogeneity, cyst or necrosis, and flow void sign were significantly higher in GBMs than AAs. The four variables, heterogeneity, cyst or necrosis, edema or mass effect and border definition, proved to be important factors related to the pathological grade in a multiple regression analysis.</p

Damage to inorganic materials illuminated by focused beam of X-ray free-electron laser radiation

X-ray free-electron lasers (XFELs) that utilize intense and ultra-short pulse X-rays may damage optical elements. We investigated the damage fluence thresholds of optical materials by using an XFEL focusing beam that had a power density sufficient to induce ablation phenomena. The 1 μ4m focusing beams with 5.5 keV and/or 10 keV photon energies were produced at the XFEL facility SACLA (SPring-8 Angstrom Compact free electron LAser). Test samples were irradiated with the focusing beams under normal and/or grazing incidence conditions. The samples were uncoated Si, synthetic silica glass (SiO2), and metal (Rh, Pt)-coated substrates, which are often used as X-ray mirror materials.Takahisa Koyama, Hirokatsu Yumoto, Kensuke Tono, Tadashi Togashi, Yuichi Inubushi, Tetsuo Katayama, Jangwoo Kim, Satoshi Matsuyama, Makina Yabashi, Kazuto Yamauchi, and Haruhiko Ohashi "Damage to inorganic materials illuminated by focused beam of x-ray free-electron laser radiation", Proc. SPIE 9511, Damage to VUV, EUV, and X-ray Optics V, 951107 (12 May 2015); https://doi.org/10.1117/12.218277

Damage threshold of coating materials on x-ray mirror for x-ray free electron laser

We evaluated the damage threshold of coating materials such as Mo, Ru, Rh, W, and Pt on Si substrates, and that of uncoated Si substrate, for mirror optics of X-ray free electron lasers (XFELs). Focused 1 μm (full width at half maximum) XFEL pulses with the energies of 5.5 and 10 keV, generated by the SPring-8 angstrom compact free electron laser (SACLA), were irradiated under the grazing incidence condition. The damage thresholds were evaluated by in situ measurements of X-ray reflectivity degradation during irradiation by multiple pulses. The measured damage fluences below the critical angles were sufficiently high compared with the unfocused SACLA beam fluence. Rh coating was adopted for two mirror systems of SACLA. One system was a beamline transport mirror system that was partially coated with Rh for optional utilization of a pink beam in the photon energy range of more than 20 keV. The other was an improved version of the 1 μm focusing mirror system, and no damage was observed after one year of operation.Takahisa Koyama, Hirokatsu Yumoto, Takanori Miura, Kensuke Tono, Tadashi Togashi, Yuichi Inubushi, Tetsuo Katayama, Jangwoo Kim, Satoshi Matsuyama, Makina Yabashi, Kazuto Yamauchi, and Haruhiko Ohashi, "Damage threshold of coating materials on x-ray mirror for x-ray free electron laser", Review of Scientific Instruments 87, 051801 (2016) https://doi.org/10.1063/1.4950723

Dynamics of the photoinduced insulator-to-metal transition in a nickelate film

The control of materials properties with light is a promising approach towards the realization of faster and smaller electronic devices. With phases that can be controlled via strain, pressure, chemical composition or dimensionality, nickelates are good candidates for the development of a new generation of high performance and low consumption devices. Here we analyze the photoinduced dynamics in a single crystalline NdNiO$_3$ film upon excitation across the electronic gap. Using time-resolved reflectivity and resonant x-ray diffraction, we show that the pump pulse induces an insulator-to-metal transition, accompanied by the melting of the charge order. Finally we compare our results to similar studies in manganites and show that the same model can be used to describe the dynamics in nickelates, hinting towards a unified description of these photoinduced phase transitions.Comment: 17 pages, 6 figure

All-optical seeding of a light-induced phase transition with correlated disorder

Ultrafast manipulation of vibrational coherence is an emergent route to control the structure of solids. However, this strategy can only induce long-range correlations and cannot modify atomic structure locally, which is required in many technologically-relevant phase transitions. Here, we demonstrate that ultrafast lasers can generate incoherent structural fluctuations which are more efficient for material control than coherent vibrations, extending optical control to a wider range of materials. We observe that local, non-equilibrium lattice distortions generated by a weak laser pulse reduce the energy barrier to switch between insulating and metallic states in vanadium dioxide by 6%. Seeding inhomogeneous structural-fluctuations presents an alternative, more energy efficient, route for controlling materials that may be applicable to all solids, including those used in data and energy storage devices

Response to Comment on “Maxima in the thermodynamic response and correlation functions of deeply supercooled water”

Caupin et al. have raised several issues regarding our recent paper on maxima in thermodynamic response and correlation functions in deeply supercooled water. We show that these issues can be addressed without affecting the conclusion of the paper.113Ysciescopu