Adsorption characteristics and separation of Cr(III) and Cr(VI) on hydrous titanium(IV) oxide

A hydrous titanium(IV) oxide was prepared to study the adsorption characteristics and the separation of chromium species. Batch sorption studies have been carried out to determine the effect of pH on the sorption of Cr(III) and Cr(VI) on hydrous TiO2. An excellent separation efficiency of Cr(III) and Cr(VI) was obtained at pH 2. The adsorption percentage of Cr(VI) was above 99%, whereas that of the Cr(III) was less than 1% at this pH. The adsorption isotherm of Cr(VI) on hydrous TiO2 at pH 2 was in good agreement with the Langmuir isotherm. The maximum adsorption capacity of Cr(VI) on TiO2 was 5 mg g(-1). The rate of adsorption of Cr(VI) by hydrous TiO2 with average particle diameter 250 and 500 microm has been studied under particle diffusion controlled conditions. The diffusion coefficients of Cr(VI) for both hydrous TiO2 having average particle diameter of 250 and 500 microm was calculated at pH 2 as 3.84 x 10(-10) m2 s(-1) and 8.86 x 10(-10) m2 s(-1), respectively.     

Effect of growth rate and lamellar spacing on microhardness in the directionally solidified Pb-Cd, Sn-Zn and Bi-Cd eutectic alloys

Lead-cadmium, Zinc-tin and Bismuth-cadmium of (99.99%) high purity eutectic alloys were melted in a graphite crucible under vacuum atmosphere. These eutectic alloys were directionally solidified upward with a constant temperature gradient G and different growth rates V in the Bridgman type directional solidification furnace. The lamellar spacings and microhardness H _V were measured from both transverse section and longitudinal section of the specimen. The variations of H _V with respect to V and have been determined by using the linear regression analysis method. H _V values increase with the increasing values of V and decrease with the increasing values. The Hall-petch type relationships obtained in this work have been compared with the previous works.     

Integrated optimal topology design and shape optimization using neural networks

In this paper, neural network- and feature-based approaches are introduced to overcome current shortcomings in the automated integration of topology design and shape optimization. The topology optimization results are reconstructed in terms of features, which consist of attributes required for automation and integration in subsequent applications. Features are defined as cost-efficient simple shapes for manufacturing. A neural network-based image-processing technique is presented to match the arbitrarily shaped holes inside the structure with predefined features. The effectiveness of the proposed approach in integrating topology design and shape optimization is demonstrated with several experimental examples.     

Antagonistic effect on Listeria monocytogenes and L. innocua of a bacteriocin-like metabolite produced by lactic acid bacteria isolated from sucuk

Two Lactobacilli and four Pediococci strains producing bacteriocin-like metabolities isolated from sucuk were tested with agar spot tests and well diffusion assays for their inhibitory activity against 16 Listeria strains, also isolated from sucuk. The production of organic acids and hydrogen peroxide limited, L. sake Lb 706 (used as a bacteriocin producer strain) and the isolated lactic acid bacteria (LAB) showed inhibitory activity against all of the Listeria strains, while L. sake Lb 706-A (used as a bacteriocin non-producer mutant) had the same effects against only two Listeria monocytogenes strains (51, 52) in agar spot tests. In the well diffusion assays, while L sake Lb 706 and four Pediococci isolates (413, 416, 419, 446) exhibited inhibitory activity against all of the Listeria strains tested, L. sake Lb 706-A and two of the Lactobacilli isolates (77, 116) showed no effect on the Listeria strains tested.     

Low-Power Tunable Analog Circuit Blocks Based on Nanoscale Double-Gate MOSFETs

We illustrate unique examples of low-power tunable analog circuits built using independently driven nanoscale DG-MOSFETs, where the top gate response is altered by application of a control voltage on the bottom gate. In particular, we provide examples for a single-ended CMOS amplifier pair, a Schmitt trigger circuit and a operational transconductance amplifier C filter, circuit blocks essential for low-noise high-performance integrated circuits for analog and mixed-signal applications. The topologies and biasing schemes explored here show how the nanoscale DG-MOSFETs may be used for efficient, tolerant and smaller circuits with tunable characteristics.     

Nearest neighbor weighted average customization for modeling faces

In this paper, we present an anatomically accurate generic wireframe face model and an efficient customization method for modeling human faces. We use a single 2D image for customization of the generic model. We employ perspective projection to estimate 3D coordinates of the 2D facial landmarks in the image. The non-landmark vertices of the 3D model are shifted using the translations of k nearest landmark vertices, inversely weighted by the square of their distances. We demonstrate on Photoface and Bosphorus 3D face data sets that the proposed method achieves substantially low relative error values with modest time complexity.     

Carbon nanotube/boehmite-derived alumina ceramics obtained by hydrothermal synthesis and spark plasma sintering (SPS)

Preparation, structure and properties of hydrothermally treated carbon nanotube/boehmite (CNT/γ-AlOOH) and densification with spark plasma sintering of Al₂O₃ and CNT/Al₂O₃ nanocomposites were investigated. Hydrothermal synthesis was employed to produce CNT/boehmite from an aluminum acetate (Al(OH)(C₂H₃O₂)₂) and multiwall-CNTs mixture (200 °C/2 h.). TEM observations revealed that the size of the cubic shape boehmite particles lies around 40 nm and the presence of the interaction between surface functionalized CNTs and boehmite particles acts to form ‘nanocomposite particles’. Al₂O₃ and CNT/Al₂O₃ compact bodies were formed by means of spark plasma sintering (SPS) at 1600 °C for 5 min using an applied pressure of 50MPa resulting in the formation of stable α-Al₂O₃ phase and CNT–alumina compacts with nearly full density. It was also found that CNTs tend to locate along the alumina grain boundaries and therefore inhibit the grain coarsening and cause inter-granular fracture mode. The DC conductivity measurements reveal that the DC conductivity of CNT/Al₂O₃ is 10^?4 S/m which indicate that there is a 4 orders of magnitude increase in conductivity compared to monolithic Al₂O₃. The results of the microhardness tests indicate a slight increase in hardness for CNT/Al₂O₃ (28.35 GPa for Al₂O₃ and 28.57 GPa for CNT/Al₂O₃).     

Determination of photoinitiated polymerization of multifunctional acrylates with acetic acid derivatives of thioxanthone by RT-FTIR

Photopolymerization of multifunctional acrylates with 2-thioxanthone-thioacetic acid (TXSCH₂COOH) and 2-(carboxymethoxy) thioxanthone (TXOCH₂COOH) as the one-component photoinitiator has been investigated by real-time Fourier transform infrared (RT-FTIR) spectroscopy. The photobleaching of these one-component nature initiators was performed in air. The irradiation time for total bleaching was 240 s for TXSCH₂COOH and 540 s for TXOCH₂COOH.