High-Speed,SAD Based Wavefront Sensor Architecture Implementation on FPGA

Wavefront aberrations caused by turbulent or rapidly changing media can considerably degrade the performance of an imaging system. To dynamically compensate these wavefront distortions adaptive optics is applied. We developed an affordable adaptive optic system which combines CMOS sensor and Liquid Crystal on Silicon (LCOS) display technology with the Field Programmable Gate Arrays (FPGA) devices parallel computing capabilities. A high-speed, accurate wavefront sensor is an elemental part of an adaptive optic system. In the paper, an efficient FPGA implementation of the Sum of Absolute Differences (SAD) algorithm, which accomplishes the correlation-based wavefront sensing, is introduced. This architecture was implemented on a Spartan-3 FPGA which is capable of real-time (>500 fps) measuring the incoming wavefront.     

Real time analysis of brain tissue by direct combination of ultrasonic surgical aspiration and sonic spray mass spectrometry

Direct combination of cavitron ultrasonic surgical aspirator (CUSA) and sonic spray ionization mass spectrometry is presented. A commercially available ultrasonic surgical device was coupled to a Venturi easy ambient sonic-spray ionization (V-EASI) source by directly introducing liquified tissue debris into the Venturi air jet pump. The Venturi air jet pump was found to efficiently nebulize the suspended tissue material for gas phase ion production. The ionization mechanism involving solely pneumatic spraying was associated with that of sonic spray ionization. Positive and negative ionization spectra were obtained from brain and liver samples reflecting the primary application areas of the surgical device. Mass spectra were found to feature predominantly complex lipid-type constituents of tissues in both ion polarity modes. Multiply charged peptide anions were also detected. The influence of instrumental settings was characterized in detail. Venturi pump geometry and flow parameters were found to be critically important in ionization efficiency. Standard solutions of phospholipids and peptides were analyzed in order to test the dynamic range, sensitivity, and suppression effects. The spectra of the intact tissue specimens were found to be highly specific to the histological tissue type. The principal component analysis (PCA) and linear discriminant analysis (LDA) based data analysis method was developed for real-time tissue identification in a surgical environment. The method has been successfully tested on post-mortem and ex vivo human samples including astrocytomas, meningeomas, metastatic brain tumors, and healthy brain tissue.     

Profiles of Work Function Shifts and Collective Charge Transfer in Submonolayer Metal–Organic Films

Vacuum level shifts Δ(d) at metal–organic (m–O) interfaces indicate the formation of surface dipoles for film thickness d ≤ d_ML up to a monolayer (ML). Shifts or profiles Δ(θ) of submonolayer films are nonlinear in the coverage θ = d/d_ML ≤ 1, which points to cooperative interactions between adsorbed molecules. Adsorption with weak nonspecific bonding is modeled as charge transfer (CT) between molecules M and localized surface states S of the metal. The dipole μ₀ of ions S^?M⁺ or S⁺M^? gives upper bounds for the vacuum level shift ? ₀ and dipole–dipole repulsion V₀ at θ = 1. Partial CT ρ(θ) < 1 is found self consistently and accounts for published profiles Δ(θ) of representative planar and nonplanar molecules with d_ML～ 4 and ～10 Å. Initial adsorption at θ ～ 0 has considerable ionic character, ρ(0) ～ 1/2, that decreases to ρ(1) ～ 1/10 at θ = 1. Planar molecules with small μ₀ and V₀ have slightly nonlinear profiles while molecules with large μ₀ and V₀ have highly nonlinear Δ(θ). Collective CT is a phenomenological model for m–O interfaces with nonspecific bonding. The CT model is contrasted to fixed dipoles on the surface, to calculations of Δ(1) and to simulations of sub‐ML films.     

Layer-by-layer assembly of TiO2 nanowire/carbon nanotube films and characterization of their photocatalytic activity

We report on the layer-by-layer (LbL) formation of TiO(2)-MWNT-TiO(2) coatings on quartz with either trititanate derived TiO(2) nanowires or Degussa P25 as the photocatalytically active material. The optimized deposition sequence is discussed in detail and the morphology of the prepared coatings is analyzed by SEM and XRD. The heterogeneous photocatalytic performance of the coatings was tested in the methyl orange oxidation reaction. The apparent first order rate constant fell in the 0.01-0.20 h(-1) range over a 2.5 × 2.5 cm(2) film depending on the type and the thickness of the titanate coating. Building a multiwall carbon nanotube layer into the middle of the layer improved the photocatalytic activity for each material for all of the studied thicknesses. P25 based films performed 2-5 times better than TiO(2) nanowire films; however, the pores in the P25 based films were largely blocked because the isotropic P25 nanoparticles form closely packed layers by themselves and even more so with the comparably sized multiwall carbon nanotubes. Therefore, films derived from titanate nanowires appear to be more suitable for use as multifunctional, photocatalytically active filtration media.     

Cultivation and characterization of pterygium as an ex vivo study model for disease and therapy

Purpose

Development of ex vivo model to study pathogenesis, inflammation and treatment modalities for pterygium.

FE Macro/Micro Models for Contact Temperature Prediction at Steel/Composite Interfaces

Finite element (FE) contact and thermal macro/micro models have been developed to study the real thermal behavior of a fiber/matrix microstructure under sliding motion of a steel asperity. At first the contact parameters were evaluated using an approximate contact technique, followed by a transient thermal FE evaluation. The latter considers the heat partition between the steel asperity and the real fiber/matrix microenvironment of a normally oriented carbon fiber/polyether ether ketone composite. The temperature results obtained were compared with those representing a macroscopic approach.     

Modified parameter-setting-free harmony search (PSFHS) algorithm for optimizing the design of reinforced concrete beams

Structural and Multidisciplinary Optimization - The design of RC members with nontraditional methods is demanding due to the large number of unknown variables inherent in the design process. The...     

A Simple Environmentally-friendly Method for the Selective Synthesis of 1,5-benzodiazepine Derivatives using Zeolite Catalyst

The modified small pore size zeolite E4a has been found to be an efficient catalyst for the regioselective synthesis of 2,3-dihydro-1H-1,5-benzodiazepines from o-phenylenediamine and ketones. This method is simple, cheap, environmentally-friendly and give the benzodiazepines in high yield.     

CS2 Poisoning of Size-Selective Cubooctahedral Pd Particles in Styrene Hydrogenation

Copper, manganese and iron phthalocyanines were found to be highly efficient catalysts for cyclopropanation of olefins using ethyldiazoacetate as carbene precursor. In general copper(II)-phthalocyanine was found to be the most active catalyst followed by the Mn(II)Pc and Fe(II)Pc. Ni(II)Pc and Co(II)Pc were found to be the less active catalysts for this reactions.