Distribution of elements in Ni-Mo-TiC alloy processed under microgravity conditions

Ni-Mo-TiC particle-strengthened alloy was processed through melting-pressing treatment of hot-pressed samples under microgravity environments by sounding rocket flight. The distributions of titanium carbide particles and elements in the alloy sample obtained were analysed using microscopy and micro Auger electron spectroscopy. The objective of this analysis was mainly to clarify the elemental distribution in the titanium carbide particle. Analysis was also carried out on the melting-pressing treated and hot-pressed samples for comparison. Analytical results showed that titanium carbide particles are uniformly distributed by the processing under microgravity and that stable mutual diffusion reaction had progressed there.     

A Novel Stacked Array Antenna with Uni-planar Compact EBG Reflector

Most broadband microstrip antennae are implemented in the form of slot structure or laminate structure,which provide a broad impedance bandwidth and meanwhile bring large sidelobes and backlobes. A novel uni-planar compact electromagnetic band-gap( EBG) structure is proposed, which shows excellent performance when applied to broadband stacked or aperture coupled microstrip array antennae. The test results indicate that,the directivity is effectively improved,and the front-to-back ratio is increased,and the thickness of the antenna is reduced. These improvements make this structure better used in airborne antennae.     

An approach for ergonomic design of mouse wheel

A new method for ergonomic design of a computer mouse is proposed in this paper.In the method,the movements of joints and tip of the forefinger during operating a mouse was captured by a high-speed video camera.The captured videos were analyzed and an algorithm was developed to decide the size and location of the mouse wheel according to ergonomic principles.The algorithm was then coded in a software package with Visual C++ and OpenGL languages.Results of the calculation and simulation agreed well with those of the experiments.The software can also be used for shape design of mouse body,buttons and their layouts.     

On cavitation occurrence in perforated plates

The hydraulics of perforated plates has a large impact on the design of water systems; particularly, estimating the inception of cavitation is fundamental for correctly assessing the performances of these devices. The work is focused on the onset of cavitation, as defined by means of the incipient cavitation number. Objects of discussion are the experimental evidences collected in two large laboratory campaigns, in which different plates with equivalent diameter ratio between 0.17 and 0.60, relative thickness between 0.11 and 4.40, and number of holes between 1 and 15 were tested. Literature experimental data, previously checked for consistency, have been added to ours in order to enlarge the experimental database. Such database was firstly employed for investigating the dependence of the incipient cavitation number upon the most relevant parameters and then for providing a formula for its estimation. In details, we propose a new correlation – based on the formula of Tullis (1993) – relating the incipient cavitation number to the discharge coefficient showing a satisfactory agreement with all the available data and therefore having a quite large applicability.     

Long-term irradiation effects of visible light on amorphous carbon nitride films

The effect of long-term visible-light irradiation on the photo-induced deformation of amorphous carbon nitride (a-CN_x) films was investigated. a-CN_x films were deposited on SiO₂ substrates (30 × 2 × 0.05 mm³) using reactive radio frequency magnetron sputtering. Deformation of the a-CN_x films was measured using continuous wave (CW) or pulsed monochromatic light with a wavelength of 470 nm. Pulsed light irradiation was applied for a total of 60 min with an on/off pulse period of 60 s, while CW light irradiation was performed for 120, 190, and 759 min with different light intensities so that the total photon flux remained constant. In all cases, the extent of photo-induced deformation of the a-CN_x films before and after irradiation did not change. The chemical bonding states determined from X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy analyses indicated no significant changes after illumination. In addition, electron spin resonance (ESR) spectroscopy measurements indicated that there was no increase in the defect density after illumination. The long-term stability of a-CN_x films is one of the main advantages for their use in light-driven microactuator systems.     

A rigorous calculation of the critical point from the fundamental equation of state for the water + ammonia mixture

The critical point of the water + ammonia mixture was calculated directly from the Helmholtz free energy formulation. The calculation was performed according to the critical point criteria expressed in terms of the derivatives of the Helmholtz free energy with respect to mole numbers. Smooth critical locus linking between the critical points of pure water and ammonia was obtained. The critical locus showed a good agreement with the most reliable experimental data. Simple correlations for the critical temperature, pressure, and molar volume for a given composition were developed. The information obtained in this study is helpful for design and simulation of the cycles using the water + ammonia mixture as working fluid.     

Environmental remediation by an integrated microwave/UV illumination method. V. Thermal and nonthermal effects of microwave radiation on the photocatalyst and on the photodegradation of rhodamine-B under UV/Vis radiation

The photocatalyzed degradation (PD) of the cationic rhodamine-B (RhB) dye was examined in aqueous TiO2 dispersions using UV/Vis illumination assisted by microwave radiation (PD/MW). The initial degradation by the PD/MW method is compared to the PD method and to the thermally assisted PD method using conventional heating (PD/TH). Total organic carbon (TOC) assays show that the efficiency of complete mineralization of the dye follows PD/MW > PD/TH > PD > MW. In all cases, microwave radiation alone had no effect on the loss of TOC. The degradation involving microwave radiation was especially efficient when coupled to UV irradiation. By contrast, the extent of degradation of RhB involving suitable excited states through visible irradiation of the dye was rather inefficient when coupled to microwave radiation. Contact angle measurements on the TiO2 photocatalyst particles indicate that microwave radiation also causes an increase in the hydrophobic character of the TiO2 surface, with consequences on the adsorption mode of the dye substrate and thus on the overall mechanism of degradation. Deethylated RhB intermediates were identified by an electrospray ESI ionization mass spectral technique in the positive ion mode and subsequently confirmed by HPLC/absorption spectroscopy. Computer simulations led to estimates of frontier electron densities of all atoms of the RhB structure, affording inferences as to the position of radical attack on RhB. The nitrogen atoms of the dye were all converted to NH4+ ions. The major difference between the thermally assisted PD/TH method and the microwave-assisted PD/MW method showed that nonthermal effects from the microwave radiation impact significantly on the nature of the photocatalyst surface. These effects led to a more efficient photodegradation and mineralization of the dye substrate.     

Impacts of city-block-scale countermeasures against urban heat-island phenomena upon a building’s energy-consumption for air-conditioning

This study quantifies the possible impacts of urban heat-island countermeasures upon buildings’ energy use during summer in Tokyo metropolis. Considering the dependency of the buildings air temperature upon the local urban canopy structure, Tokyo urban canopies were classified in the city-block-scale using the sky-view factor (svf). Then, a multi-scale model system describing the interaction between buildings’ energy use and urban meteorological conditions was applied to each classified canopy.