Mechanical properties and microstructures of rapidly solidified Al89.5Ni8Zr2.5 and Al88.5Ni8Ti3.5 alloys

Al89.5Ni8Zr2.5 and Al88.5Ni8Ti3.5 alloys extruded from their rapidly solidified powders have tensile strength more than 800 MPa and Young's modulus about 100 GPa. The extruded Al89.5Ni8Zr2.5 alloy is composed of -Al, Al3Ni and a metastable tetragonal Al3Zr, and the extruded Al88.5Ni8Ti3.5 alloy consists of -Al, Al3Ni and equilibrium Al3Ti. Through investigation on microstructure change of rapidly solidified Al89.5Ni8Zr2.5 and Al88.5Ni8Ti3.5 alloys with temperature, it is found that a new tetragonal Al3Zr phase, together with -Al and Al3Ni precipitates from the supersaturated -Al phase in the rapidly solidified Al89.5Ni8Zr2.5 alloy at around 603 K and an equilibrium Al3Ti, together with -Al and Al3Ni forms from the supersaturated -Al phase in the rapidly solidified Al88.5Ni8Ti3.5 alloy at about 523 K. The lattice parameters of the new metastable tetragonal Al3Zr phase were calculated to be a=0.3896 nm and c=0.9006 nm. Both the metastable tetragonal Al3Zr and equilibrium Al3Ti phases keep a nano grain size, less than 50 nm even at 773 K. The existence of the nano scale Al3Zr, Al3Ti phases and fine grains of -Al, Al3Ni phases is the reason that Al89.5Ni8Zr2.5 and Al88.5Ni8Ti3.5 alloys have the high strength. © 1998 Chapman & Hall     

Minimum void ratio characteristic of soils containing non-plastic fines

The minimum void ratio is an index widely used to indicate the contraction characteristics and the densest state of soils. The minimum void ratio obtained by the traditional test method has been utilized to represent the density of soils irrespective of their fines content despite the restriction (FC ≤ 5%). By considering the effect of the blow count, pore water, and their primary properties, the applicability of the minimum void ratio to soils containing fines was examined with an automatic tapping machine. It was confirmed that the blow count of the traditional method is not sufficient for soils with a high fines content. Furthermore, the presence of pore water had a significant effect on the minimum void ratio of soils containing fines. The characteristics of the cyclic minimum void ratio, which indicates the minimum void ratio obtained throughout the repetition of liquefaction and drainage, were also examined.     

A comparison of historical land-use change patterns and recommendations for flood plain developments in three delta regions in Southeast Asia

Historical land-cover changes in three delta regions in Southeast Asia are assessed by using selected Landsat images from 1990 to 2005. Potential inundation areas of the delta regions for different return periods are estimated by using digital elevation model data and extreme-value distribution of annual maximum river discharges. The results indicate significant changes of natural land cover within the potential inundation areas due to agricultural exploitation and industrialization. Implications for flood-mitigation policies are discussed. There is a clear need for sustainable land-use management strategies in all three areas.     

Reservoir Release Policy for Large Irrigation System

This paper describes the formulation of a model for optimized crop and water planning decisions in an irrigation system in Thailand. It facilitates consultation in which representatives of stakeholders, officials, farmers, and researchers can contribute to the decision making. Linear programming and the analytical hierarchy process are the principal modeling tools to optimize the collective system objectives: productivity, equity, and security. The results of the model are compared with observed events of one dry season. The optimized policy generated by the model suggested a diversified cropping pattern, which would decrease the water requirement by 16.4% and enhance net benefit per cubic meter of water used by 39.9%. The erratic water availability from the reservoir and the operational procedures inside the system are reviewed, analyzing historical data in terms of reliability, resiliency, and vulnerability. These include lack of proper assessment of available water, effective farmer organization, and prompt data processing and communication. Furthermore, for the effective implementation of an optimized irrigation policy, a water release pattern of the storage reservoir has been suggested.     

Indoor air quality,air exchange rates,and radioactivity in new built temporary houses following the Great East Japan Earthquake in Minamisoma,Fukushima

This study measured air exchange rates, indoor concentrations of aldehydes and volatile organic compounds (VOCs), and radioactivity levels at 19 temporary houses in different temporary housing estate constructed in Minamisoma City following the Great East Japan Earthquake. The 19 surveyed houses represented all of the companies assigned to construct temporary houses in that Minamisoma City. Data were collected shortly after construction and before occupation, from August 2011 to January 2012. Mean air exchange rates in the temporary houses were 0.28/h, with no variation according to housing types and construction date. Mean indoor concentrations of formaldehyde, acetaldehyde, toluene, ethylbenzene, m/p‐xylene, o‐xylene, styrene, p‐dichlorobenzene, tetradecane, and total VOCs (TVOCs) were 29.2, 72.7, 14.6, 6.35, 3.05, 1.81, 7.29, 14.3, 8.32, and 901 μg/m³, respectively. The levels of acetaldehyde and TVOCs exceeded the indoor guideline (48 μg/m³) and interim target (400 μg/m³) in more than half of the 31 rooms tested. In addition to guideline chemicals, terpenes (α‐pinene and d‐limonene) and acetic esters (butyl acetate and ethyl acetate) were often detected in these houses. The indoor radiation levels measured by a Geiger–Müller tube (Mean: 0.22 μSv/h) were lower than those recorded outdoors (Mean: 0.42 μSv/h), although the shielding effect of the houses was less than for other types of buildings.     

EPR study of the electronic states of β′-(BEDT-TTF)(TCNQ)

β′-(BEDT-TTF)(TCNQ) is a compound of BEDT-TTF (=ET) and TCNQ molecules aligned orthogonally with each other, forming two-dimensional sheets and one-dimensional columns of 1/4-filled π band, respectively. It is known that the metal-insulator transition occurs at 330 K at ambient pressure. We have measured the electronic spin susceptibility by means of the EPR-NMR method at 50 MHz, and the angular dependence of g-factor and line width of EPR both at Q (34 GHz) and W (94 GHz) band. We successfully confirmed that the antiferromagnetic transition occurs in ET sheets and TCNQ columns, independently.     

Incoherent-scatter computed tomography with monochromaticsynchrotron x ray: feasibility of multi-CT imaging system forsimultaneous measurement-of fluorescent and incoherent scatter x rays

We describe a new system of incoherent scatter computed tomography (ISCT) using monochromatic synchrotron X rays, and we discuss its potential to be used in in vivo imaging for medical use. The system operates on the basis of computed tomography (CT) of the first generation. The reconstruction method for ISCT uses the least squares method with singular value decomposition. The research was carried out at the BLNE-5A bending magnet beam line of the Tristan Accumulation Ring in KEK, Japan. An acrylic cylindrical phantom of 20-mm diameter containing a cross-shaped channel was imaged. The channel was filled with a diluted iodine solution with a concentration of 200 μgI/ml. Spectra obtained with the system's high purity germanium (HPGe) detector separated the incoherent X-ray line from the other notable peaks, i.e., the iK_α and K_β1 X-ray fluorescent lines and the coherent scattering peak. CT images were reconstructed from projections generated by integrating the counts In the energy window centering around the incoherent scattering peak and whose width was approximately 2 keV. The reconstruction routine employed an X-ray attenuation correction algorithm. The resulting image showed more homogeneity than one without the attenuation correction     

Method for calculating temperature rise in cables in bridge ducts

To permit calculation of the power transmission capacity of cables carried in bridge ducts, methods for calculating the thermal resistance and capacity of a bridge and changes in the transient temperature of cables in bridge ducts are proposed. The validity of these methods is confirmed by tests on bridges. It is also found that the heat trapped in the duct can be estimated by a convection computation taking radiation into due consideration     

Repetition bend properties of Cu-Cr and Cu-Cr-Sn alloys

Repetition numbers of bending of Cu-0.81 wt% Cr, Cu-0.81 wt% Cr-0.14 wt% Sn and Cu-0.26 wt% Cr-0.10 wt% Sn alloys were investigated. After solution treatment, the first two types of copper alloys have a primary chromium phase; this is not so in the last alloy. The primary chromium phase does not influence the repetition numbers of bending of cold-rolled specimens; the repetition numbers of bending of specimens aged at 723 K for 1.8 × 10³ sec after cold rolling are higher than those of cold-rolled specimens. The cause of this is considered to be a recovery of work-hardening during ageing.