This study investigated how surface defects affect the fatigue performance of laser powder bed fusion (LPBF) Ti6Al4V(ELI) test specimens in as-built surface roughness and heat-treated conditions. ...Tensile and fatigue specimens were built in three orthogonal directions for testing. Fatigue testing was carried out to determine the maximum stress at which a run-out number of 5 million cycles to failure could be achieved. Fractured specimens were analysed and compared for crack initiation and propagation characteristics using scanning electron microscopy. Conclusions were drawn on the possibility of producing Ti6Al4V(ELI) aircraft components through LPBF.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Atomic layer deposition of SiO2 from tris(dimethylamino)silane (TDMAS) and ozone as precursors on Si(100) surfaces at near-room temperatures was studied by infrared absorption spectroscopy with a ...multiple internal reflection geometry. TDMAS can be adsorbed at OH sites on hydroxylated Si surfaces at room temperature. Ozone oxidation of the TDMAS-treated Si surface is effective in removing hydroaminocarbon adsorbates introduced during TDMAS adsorption at room temperature. After oxidation by ozone, treatment with H2O vapor at a substrate temperature of around 160AC causes regeneration of OH sites for TDMAS adsorption. Cycles involving TDMAS adsorption and ozonization at room temperature followed by H2O treatment at 160AC permit the buildup of layers of SiO2. The amount of residual hydroaminocarbon at the interface between the growing SiO2 film and the substrate can be reduced with the ozone treated Si surface as a starting surface.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
•Report on recent achievement of the SHARAQ spectrometer.•Demonstration of two ion optics modes for high-resolution spectroscopy.•Discussion on measured transport matrix elements by comparison with ...designed values.•Demonstration of event-by-event momentum tagging by the achromatic transport.•Achievement of momentum resolution of 1/8100 by the dispersion-matching transport.
The SHARAQ spectrometer and High-Resolution Beamline, which began operation in March 2009, have been put into use for six experiments using charge exchange reactions with radioactive isotope beams. For experiments at SHARAQ, detector developments and ion optics studies continue to improve performance in high-resolution nuclear spectroscopy. We have introduced improved timing resolution with CVD diamond detectors, high count-rate beamline tracking detectors and development of multi-particle detection by cathode-readout drift chambers. Ion-optics studies for the high-resolution achromatic (HA) and dispersion-matching (DM) transport modes are also reported here. Momentum tagging in the HA mode demonstrated an improvement in spectroscopic resolution with respect to the momentum spread of the radioactive beam. For the DM transportation mode, a momentum resolution of 1/8100 (FWHM) was achieved by taking into account the positions and angles of the beam at the third focal plane of BigRIPS.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
•Report on recent development of the polycrystalline CVD diamond detector.•Thin detector with extremely good timing resolution for time-of-flight measurements.•Irradiation experiment for examining ...the basic performance of the diamond detector.•Achievement of timing resolution of 30ps for intermediate-energy light ion beams.•Signal transfer systems with an optical fiber achieved a small jitter of 10.7ps.
The paper describes recent developments of diamond detector at CNS and discusses the timing signal transfer system suitable for optimizing its performance. The diamond detector is well known to have good properties as a radiation detector such as fast response and good radiation hardness. Consequently, it is an excellent candidate for serving as a high-resolution thin timing detector. CNS and NSCL/MSU started a collaboration to develop diamond detectors, and manufactured a detector with a size of 28 ×28mm2 and thickness of 200μm. An irradiation experiment of the detector was performed by using a 32-MeV α beam to check its basic performance. The CNS detector had almost 100% efficiency and a timing resolution of 27ps (σ). Jitter in long optical-fiber signal-transfer lines was examined and found to be 10.7ps (σ). Diamond detectors and signal transfer system using a optical fiber enable us to provide time-of-flight measurements with extremely high resolution.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Remote sensing offers a cost efficient means for identifying and monitoring wetlands over a large area and at different moments in time. In this study, we aim at providing ecologically relevant ...information on characteristics of temporary and permanent isolated open water wetlands, obtained by standard techniques and relatively cheap imagery. The number, surface area, nearest distance, and dynamics of isolated temporary and permanent wetlands were determined for the Western Cape, South Africa. Open water bodies (wetlands) were mapped from seven Landsat images (acquired during 1987 - 2002) using supervised maximum likelihood classification. The number of wetlands fluctuated over time. Most wetlands were detected in the winter of 2000 and 2002, probably related to road constructions. Imagery acquired in summer contained fewer wetlands than in winter. Most wetlands identified from Landsat images were smaller than one hectare. The average distance to the nearest wetland was larger in summer. In comparison to temporary wetlands, fewer, but larger permanent wetlands were detected. In addition, classification of non-vegetated wetlands on an Envisat ASAR radar image (acquired in June 2005) was evaluated. The number of detected small wetlands was lower for radar imagery than optical imagery (acquired in June 2002), probably because of deterioration of the spatial information content due the extensive pre-processing requirements of the radar image. Both optical and radar classifications allow to assess wetland characteristics that potentially influence plant and animal metacommunity structure. Envisat imagery, however, was less suitable than Landsat imagery for the extraction of detailed ecological information, as only large wetlands can be detected. This study has indicated that ecologically relevant data can be generated for the larger wetlands through relatively cheap imagery and standard techniques, despite the relatively low resolution of Landsat and Envisat imagery. For the characterisation of very small wetlands, high spatial resolution optical or radar images are needed. This study exemplifies the benefits of integrating remote sensing and ecology and hence stimulates interdisciplinary research of isolated wetlands.
•Multi-wire drift chambers were developed for high intensity beams of 1MHz.•Low-pressure gas is used to minimize the effect of multiple scattering.•Tracking efficiencies reached almost 90% for Z from ...2 to 7.•Position resolution of 300μm was achieved for beams of 1MHz.
Low-pressure multi-wire drift chambers have been developed to track high-intensity radioactive isotope beams at the energies of around 200MeV/nucleon. In order to minimize the effect of multiple scattering by radioactive isotope beam, the thickness of the detectors were minimized by using isobutane gas at low pressure (10kPa). The performance of the position resolution, the tracking efficiency, and the beam intensity capability were evaluated as a function of atomic number and applied voltage. As a result, an overall position resolution of 300 μm was achieved for radioactive isotope beams with an intensity of 1MHz. The details of the design specifications and performances of the low-pressure multi-wire drift chambers are described.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
7.
BigRIPS as a high resolution spectrometer for pionic atoms Nishi, T.; Berg, G.P.A.; Dozono, M. ...
Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms,
12/2013, Volume:
317
Journal Article
Peer reviewed
We are presently working on a new project ‘pionic atom factory project’ at RIBF. The project aims at precision spectroscopy of the energy spectrum of the pionic atom for a wide range of elements, ...using missing-mass spectroscopy of the (d,3He) reaction near the π- emission threshold. For this project, we developed a new ion optics for BigRIPS using the dispersion-matching method. In this optics the BigRIPS beam line is used as a high resolving-power forward angle spectrometer to momentum-analyze 3He. We are aiming for a spectral resolution of <400keV (FWHM). An overview of the new optics and the result of a pilot experiment are reported.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Transforming growth factor (TGF)-β regulates many aspects of wound repair including inflammation, chemotaxis, and deposition of extracellular matrix. We previously showed that epithelialization of ...incisional wounds is accelerated in mice null for Smad3, a key cytoplasmic mediator of TGF-β signaling. Here, we investigated the effects of loss of Smad3 on healing of wounds in skin previously exposed to ionizing radiation, in which scarring fibrosis complicates healing. Cutaneous wounds made in Smad3-null mice 6 weeks after irradiation showed decreased wound widths, enhanced epithelialization, and reduced numbers of neutrophils and myofibroblasts compared to wounds in irradiated wild-type littermates. Differences in breaking strength of wild-type and Smad3-null wounds were not significant. As shown previously for neutrophils, chemotaxis of primary dermal fibroblasts to TGF-β required Smad3, but differentiation of fibroblasts to myofibroblasts by TGF-β was independent of Smad3. Previous irradiation-enhanced induction of connective tissue growth factor mRNA in wild-type, but not Smad3-null fibroblasts, suggested that this may contribute to the heightened scarring in irradiated wild-type skin as demonstrated by Picrosirius red staining. Overall, the data suggest that attenuation of Smad3 signaling might improve the healing of wounds in previously irradiated skin commensurate with an inhibition of fibrosis.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The spectroscopy of deeply bound pionic atoms provides a way to understand the restoration of chiral symmetry breaking at finite density. We have been performing a series of experiments of ...missing-mass spectroscopy of the (d,3He) reaction at RIBF to investigate pionic atoms of several Sn isotopes. As a first step, we conducted a pilot experiment to measure deeply bound pionic states of 121Sn and successfully observed the deeply bound pionic states. In addition to the experiment at RIBF, we are planning the spectroscopy of deeply bound pionic atoms in inverse kinematics and conducted a feasible study by simulations. We showed that by using a deuterium gaseous active target TPC and silicon detectors, the Q-value resolution is about 500 keV (FWHM) and the yield of the pionic 1s state is 20 counts/day, indicating the experiment is feasible.
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