Effect of compression overload on fatigue strength improved by ICR treatment

ICR (Impact Crack-closure Retrofit) treatment was developed for extending fatigue life of cracked steel structures by closing the fatigue crack opening. By applying the ICR treatment to as-welded condition, compressive stress remains at weld toe. Therefore, ICR treatment can be used for the improvement of fatigue strength of welded joint at the same level of the other fatigue strength improved techniques. If a compression overload is subjected after ICR treatment, however, the residual compressive stress at weld toe will shift the tensile stress region. Accordingly, improved fatigue strength of welded joints by ICR treatment will be reduced after the compression overloaded. In order to investigate the effect of the compression overload on fatigue strength improved by ICR treatment, fatigue tests of out-of-plane gusset specimens were carried out. As the results, fatigue strength improved by ICR treatment was hardly reduced under the compression overload condition of nominal stress of ?190 MPa.     

Elastic constants of langasite and alpha quartz at high temperatures measured by antenna transmission acoustic resonance

A method for measuring elastic constants of piezoelectric materials at high temperature up to 1224 K is proposed. It determines all independent elastic constants by measuring resonance frequencies of a rectangular parallelepiped piezoelectric specimen contactlessly using its own piezoelectricity with an antenna. Without using conventional contacting piezoelectric transducers, vibrational sources are excited directly in the specimen by the oscillating electric field. Capability of the method is demonstrated by measuring the elastic constants of langasite at high temperature up to 1224 K, and temperature coefficients of the elastic constants are determined. In addition, elastic constants of alpha quartz are measured at high temperature up to just below the alpha-beta phase transition temperature. Considering the local deformation with temperature increment, an interpretation based on the strain energy reduction is proposed for the unusual temperature dependence of C(66). Furthermore, the internal-friction tensor is measured, and the relationship between the observed anisotropy in internal friction and the structural evolution with temperature increment is discussed.     

Differential phase contrast x-ray microimaging with scanning-imaging x-ray microscope optics

A novel x-ray microimaging system that consists of a scanning microscope optics with a one-dimensional focusing (line-focusing) device and an imaging microscope optics with a one-dimensional objective is developed. These two optical systems are set normal to each other regarding the optical axis. A two-dimensional image is obtained with one-dimensional translation scan of the line probe. During scans, positional data in the normal to the scanning direction are obtained simultaneously with the imaging microscope optics. Differential phase contrast (DPC) image and absorption contrast (AC) image can be arbitrarily obtained by image processing after data acquisition. Preliminary experiment has been carried out by using a couple of one-dimensional Fresnel zone plate as the linear-focusing device and the one-dimensional objective. Two-dimensional DPC and AC images of test sample have been successfully obtained with 8 keV x-rays.     

Microstructural Characterization of Porous Silicon Carbide Membrane Support With and Without Alumina Additive

Porous silicon carbide (SiC) membrane supports sintered at 1500°–1800°C were prepared by cold isostatic pressing (CIP) under different pressures and using different amounts of alumina additive (0%–4%). The relationship between processing factors and pore size and microstructure was examined. Varying the sintering temperature, the CIP pressure and the amount of additive used were found to be effective for controlling pore size and microstructure. The pore size and particle size of the membrane support prepared without alumina were found to increase with increasing sintering temperature. This was attributed to surface diffusion. Densification of the undoped support did not occur, however, because of concurrent pore development. In the SiC membrane support containing 4% alumina, small particles and a pore size of around 100 nm were retained. This was because of the formation of a limited amount of SiO₂–Al₂O₃ liquid phase during sintering.     

Lead Evaluation of Tetrahydroquinolines as Nonsteroidal Selective Androgen Receptor Modulators for the Treatment of Osteoporosis

Tetrahydroquinoline (THQ) was deemed to be a suitable scaffold for our nonsteroidal selective androgen receptor modulator (SARM) concept. We adapted the strategy of switching the antagonist function of cyano‐group‐containing THQ (CN‐THQ) to the agonist function and optimized CN‐THQ as an orally available drug candidate with suitable pharmacological and ADME profiles. Based on binding mode analyses and synthetic accessibility, we designed and synthesized a compound that possesses a para‐substituted aromatic ring attached through an amide linker. The long‐tail THQ derivative 6‐acetamido‐N‐(2‐(8‐cyano‐3a,4,5,9b‐tetrahydro‐3H‐cyclopenta[c]quinolin‐4‐yl)‐2‐methylpropyl)nicotinamide ( 1 d ), which bears a para‐acetamide‐substituted aromatic group, showed an appropriate in vitro biological profile, as expected. We considered that the large conformational change at Trp741 of the androgen receptor (AR) and the hydrogen bond between 1 d and helix 12 of the AR could maintain the structure of the AR in its agonist form; indeed, 1 d displays strong AR agonistic activity. Furthermore, 1 d showed an appropriate in vivo profile for use as an orally available SARM, displaying clear tissue selectivity, with a separation between its desirable osteoanabolic effect on femoral bone mineral density and its undesirable virilizing effects on the uterus and clitoral gland in a female osteoporosis model.     

Evaluation of Strain Field Around Impacted Particles by Applying Electron Moiré Method

Recently, the thermal-spray community has focused considerable attention on cold-spray and warm-spray techniques, in which the temperatures of sprayed particles are kept below their melting point and adhesion occurs based on the impact phenomenon between a solid particle and a substrate. The mechanisms of adhesion are still unclear, but the degree of the mechanical deformation at the interface is considered to be a key factor influencing this mechanism. However, it is very difficult to directly measure the strain at the interface. Instead, in this work, the strain fields on a substrate around an impacted particle sprayed by warm-spray deposition were measured by applying electron Moiré method, and compared with numerical simulation results. This article is an invited paper selected from presentations at the 2007 International Thermal Spray Conference and has been expanded from the original presentation. It is simultaneously published in Global Coating Solutions, Proceedings of the 2007 International Thermal Spray Conference, Beijing, China, May 14-16, 2007, Basil R. Marple, Margaret M. Hyland, Yuk-Chiu Lau, Chang-Jiu Li, Rogerio S. Lima, and Ghislain Montavon, Ed., ASM International, Materials Park, OH, 2007.     

Determining temperature distribution on flank face of cutting tool

The temperature distribution of the tool flank face is measured by a simple method in this report. After drilling a small hole in the work, a fine metal wire (0.02 mm diam) is inserted and both the work and the wire are cut together. At the time of wire cutting, the end of the wire is in contact with the cutting edge and moves on the tool flank face. A thermoelectric couple is formed between the tool flank and the fine wire and then the temperature distribution on the tool flank face can be measured. Temperature distribution generally forms a trapezoid, regardless of cutting conditions and width of flank wear. The maximum temperature on tool flank is not affected by cutting condition.     

Optical properties of a total-reflection-type one-dimensionalphotonic crystal

We produced an asymmetric Fabry-Perot microcavity using total reflection, and its optical properties were investigated. The structure is considered to be a total-reflection-type 1-D photonic crystal. An electric-field enhancement of incident light in a defect layer installed inside the photonic crystal was observed by fluorescence emission from dye molecules doped into the defect layer division. We confirmed that the incident light intensity was strengthened by about 63 times in the defect layer     

Wireless Measurement System for Ground-borne Vibration and Vibration Amplifications in Buildings

The environmental impact on residents of buildings, such as adverse effect on sleep and physical discomfort is caused by ground-borne vibration sources such as rail transit systems, road traffic, construction sites, and industrial plants. To estimate the impact of these vibrations on the residents, it is necessary to measure the tri-axial vibrations in the vertical and horizontal directions of the buildings as specified in the international standard regulated by ISO 2631-2:2003. A wireless measurement system for simple and accurate measurement of building vibration was developed. Five wireless vibration measurement devices (installed together with a data recorder in the building) are controlled simultaneously by an outdoor mobile PC or a laboratory PC via wireless local area network and an Internet connection. It sends the vibration acceleration waveforms recorded in buildings over the wider internet communication system to the laboratory PC. The wireless measurement system was used for measuring vibration in two- and three-story detached houses of wooden or steel construction. The impact on the residents may be caused by the vibration amplifications associated with building structural resonances. The vibration amplifications in 120 houses were evaluated as ratios and level differences in 1/3 octave band vibration accelerations measured at the ground near the substructure and floors.     

Development of a gallium-doped germanium far-infrared photoconductor direct hybrid two-dimensional array

To our knowledge, we are the first to successfully report a direct hybrid two-dimensional (2D) detector array in the far-infrared region. Gallium-doped germanium (Ge:Ga) has been used extensively to produce sensitive far-infrared detectors with a cutoff wavelength of approximately equal to 110 microm (2.7 THz). It is widely used in the fields of astronomy and molecular and solid spectroscopy. However, Ge:Ga photoconductors must be cooled below 4.2 K to reduce thermal noise, and this operating condition makes it difficult to develop a large format array because of the need for a warm amplifier. Development of Ge:Ga photoconductor arrays to take 2D terahertz images is now an important target in such research fields as space astronomy. We present the design of a 20 x 3 Ge:Ga far-infrared photoconductor array directly hybridized to a Si p-type metal-oxide-semiconductor readout integrated circuit using indium-bump technology. The main obstacles in creating this 2D array were (1) fabricating a monolithic Ge:Ga 2D array with a longitudinal configuration, (2) developing a cryogenic capacitive transimpedance amplifer, and (3) developing a technology for connecting the detector to the electronics. With this technology, a prototype Ge:Ga photoconductor with a direct hybrid structure has shown a responsivity as high as 14.6 A/W and a minimum detectable power of 5.6 x 10(-17) W for an integration time of 0.14 s when it was cooled to 2.1 K. Its noise is limited by the readout circuit with 20 microV/Hz(1/2) at 1 Hz. Vibration and cooling tests demonstrated that this direct hybrid structure is strong enough for spaceborne instruments. This detector array will be installed on the Japanese infrared satellite ASTRO-F.