mm-wave phased arrays in silicon with integrated antennas

This work demonstrates W-band integrated dipole antennas and a four channel phased transceiver implemented in IBM 130 nm silicon germanium BiCMOS process. The chip includes the complete receiver, transmitter, signal generation blocks, phase shifters, and on-chip dipole antennas. A hemispherical silicon lens with diameter of about one inch is also used to remove the substrate modes. Measurement results show a maximum antenna gain of about +8 dB

Key Information Retrieval in Hyperspectral Imagery through Spatial-Spectral Data Fusion

Hyperspectral (HS) imaging is measuring the radiance of materials within each pixel area at a large number of contiguous spectral wavelength bands. The key spatial information such as small targets and border lines are hard to be precisely detected from HS data due to the technological constraints. Therefore, the need for image processing techniques is an important field of research in HS remote sensing. A novel semisupervised spatial-spectral data fusion method for resolution enhancement of HS images through maximizing the spatial correlation of the endmembers (signature of pure or purest materials in the scene) using a superresolution mapping (SRM) technique is proposed in this paper. The method adopts a linear mixture model and a fully constrained least squares spectral unmixing algorithm to obtain the endmember abundances (fractional images) of HS images. Then, the extracted endmember distribution maps are fused with the spatial information using a spatial-spectral correlation maximizing model and a learning-based SRM technique to exploit the subpixel level data. The obtained results validate the reliability of the technique for key information retrieval. The proposed method is very efficient and is low in terms of computational cost which makes it favorable for real-time applications

Investigating the Effect of Mechanical Activation Parameters on Structural Changes and Leaching Rate of Molybdenite Concentrate

AbstractIn this research, mechanical activation (MA) was employed for leaching rate improvement of molybdenite concentrate in nitric acid media. These experiments were performed in two groups: with and without aluminum oxide (alumina). A full factorial design was used for each group of experiments. Leaching rate increment up to 5 times was observed only in 2hours activation procedure. XRD analysis demonstrated structural disordering in activated MoS2. TEM images showed that particle size has been reduced to nanoscale. The initial powder size was 80% between 2-44μm and dropped to about 10nm and 140nm in MA experiments with and without alumina, respectively. This size reduction would be the main reason of leaching rate enhancement which is more achievable in MA in presence of alumina. The results demonstrate that alumina has a motivating effect in activation procedure to achieve a nanostructure molybdenite. Analysis of variance revealed milling speed is the main parameter in MA without alumina, while, ball to powder ratio is the most important factor in MA procedure in presence of alumina on leaching rate

Existence of Positive Solutions for Multiterm Fractional Differential Equations of Finite Delay with Polynomial Coefficients

Existence of positive solutions has been studied by A. Babakhani and V. Daftardar-Gejji (2003) in case of multiterm nonautonomous fractional differential equations with constant coefficients. In the present paper we discuss existence of positive solutions in case of multiterm fractional differential equations of finite delay with polynomial coefficients

An innovative design of actuation mechanism for active seat suspension of an off-road vehicle

In recent years human-machine interaction attracts scientific community attention because of human quality and health issues. Driver seat should be designed so that it would ensure occupational health as well as increase work efficiency. The aim of this research is to maintain seat height at constant level with regard to chassis excitation at different levels of frequency and amplitude by means of new design of pneumatic actuation circuit. Sinusoidal function was used for base vibration since almost all of excitation functions can be derived from it. System response shows in low frequency/high amplitude and high frequency/low amplitude chassis vibration, transmissibility decreased about 60% and 40% compared to solid suspension respectivel

Recycled cobalt from spent Li-ion batteries as a superhydrophobic coating for corrosion protection of plain carbon steel

A new recycling and film formation scheme is developed for spent Li-ion batteries, which involves the combination of ascorbic-assisted sulfuric leaching and electrodeposition to fabricate a corrosion resistance superhydrophobic coating. The idea behind the simultaneous use of sulfuric and ascorbic is to benefit from the double effect of ascorbic acid, as a leaching reducing agent and as morphological modifier during electrodeposition. Quantum chemical calculations based on the density functional theory are performed to explain the cobalt-ascorbate complexation during the electrocristalization. The optimum parameters for the leaching step are directly utilized in the preparation of an electrolyte for the electrodeposition process, to fabricate a superhydrophobic film with a contact angle of > 150\ub0 on plain carbon steel. The potentiodynamic polarization measurments in 3.5 wt % NaCl showed that boric-pulsed electrodeposited cobalt film has 20-times lower corrosion current density and higher corrosion potential than those on the non-coated substrate

Synthesis of a Multilayer Ceramic Membrane Used for Hydrogen Separation at High Temperature

A multilayer composite ceramic membrane was prepared by depositing a nano-scale layer of SiO2 on top of a modified porous alumina support by chemical vapor deposition (CVD) method. The modification of the support was carried out by adding a graded layer of Al2O3 (γ-alumina phase), using sol-gel method. An optimized temperature of 700 K for intermediate layer calcination was gained by XRD analysis. Cross-sectional images obtained from SEM showed that the intermediate γ-alumina layer had a thickness of about 2 μm and the top selective silica layer was quite dense and uniform with a thickness of about 90-100 nm. Permeation tests showed a very good flux of 10-6-10-7 mol m-2 s-2 Pa-1 for H2 with selectivities over CO2, N2 and CH4 up to 500. By performing different tests with various deposition times, it was concluded that by changing CVD time from 3 h to 6 h H2/CO2 selectivity increased from 32 to 573, although H2  permeation flux reduced about 50 percent

Preparation of BaCe0.9Yb0.1O3-δ asymmetrical membrane for hydrogen separation at high tempratures

A mixed proton–electron conducting perovskite was synthesized by liquid-citrate method and the corresponding membrane was prepared by pressing followed by sintering. The hydrogen permeability of BaCe0.9Yb0.1O3-δ was studied as a function of temperature and hydrogen partial pressure (PH2) gradient. Using 100% dry hydrogen at 1173 K, the hydrogen permeation rate of dense membranes (1.63 mm thick) for a mixture of 60% H2/He was 0.000293 mol/(m2 s). The phase structure of powder was characterized by X-ray diffraction and thermogravimetry (TG). Scanning electron microscopy (SEM) was used to investigate the microstructure of sintered membrane. Activation energy estimated with Arrhenius equation was 29 kJ/mol