Preparation of V/ZrO2 catalysts by the sol-gel method: Physical and structural characterization

Some zirconia-supported vanadium oxides have been prepared by sol-gel method and characterized by different techniques. The vanadium content exerts an effect on the area and pore-size of precursors and samples calcined. The presence of vanadium also affects the decomposition of precursors into ZrO₂ and to its phase transformation, as well as the formation of fibres, as shown by SEM-EDX. XPS analyses show the presence of two species of vanadium at the surface, V^5– and V⁴⁺, the percentage of each one depending on the load of vanadium in the catalyst.     

A network analyzer-based tissue characterization system

A novel ultrasound tissue characterization system is described which utilizes a network analyzer, S-parameter test set, 180° hybrid junction, and a mock transducer circuit to exploit the wide-band potential of a commercial piezoelectric polymer transducer. The relatively short round-trip pulselength achieved using the system (70 ns in water) is compared to that obtained using a high-frequency pulser/receiver and the same transducer (130 ns in water). Finally, the in vitro acoustic response of a section of neonate porcine carotid artery obtained using the network analyzer-based system is reported, along with histologic results for the same vessel     

Educational experiments in machine vision

We present a set of four educational experiments in machine vision. These were designed to run on low-cost hardware which is yet powerful enough to serve in genuine industrial applications of machine vision. The experiments introduce students to thresholding, connected component analysis, Hough transforms, stereo vision, and color coordinate systems. The programming involved is close enough to the hardware to expose students to real-time processing techniques and prepares them to tackle the type of problems they will face in field applications of machine vision. The experiments are: locate coins in an image, identify their denominations, and count the amount of money present; extract the straight edges of a cube by the Hough transform technique; extract three-dimensional (3-D) information from left and right images of the same cube; and transform color images from RGB to HSI coordinates and visually assess the results     

Pressure ulcer development

VDD pacing follow-up is similar in pediatric and adult patients. Atrial and ventricular pacing parameters are stable during 2-year follow-up in children, and single-pass lead VDD pacing is recommended when the sinus node function is normal.