Investigation of photocatalytic degradation of clindamycin antibiotic by using nano-ZnO catalysts

The photocatalytic degradation of clindamycin (CLM) was studied by a batch reactor using UV irradiation and ZnO catalyst. The effects of several parameters such as pH, catalyst loading, light intensity and irradiation time were evaluated in the removal process. The results showed that the degradation of CLM was effective in alkaline conditions. The optimum catalyst loading in an aqueous solution containing 25 mM of CLM and UV lamp of 50 W was observed at 3.0 g/L of catalyst loading. The process followed pseudo-first order kinetics, and the apparent rate constant (k) decreased with increasing the initial concentration of CLM. The photocatalytic process had higher removal efficiency in synthetic than actual wastewater in optimum conditions.     

Facile Synthesis Optimization and Structure Characterization of Zinc Tungstate Nanoparticles

The study involves a direct precipitation method developed for the facile and efficient synthesis of ZnWO₄ nanoparticles. Effects of various parameters such as zinc and tungstate ion solution concentrations, flow rate of reagent addition, and reactor temperature on diameter of synthesized zinc tungstate nanoparticles were investigated experimentally by the aid of orthogonal array design. The findings of the study revealed that the diameter of the produced ZnWO₄ nanoparticles can be fine-tuned through the adjustment of the reaction parameters, including zinc and tungstate ion solution concentrations and the reaction temperature, and at optimum conditions of synthesis procedure, the size of the produced zinc tungstate particles was about 33 nm. Finally, scanning electron microscopy, X-ray diffraction, FTIR, and photoluminescence techniques were used for structural and morphological characterization of the product, so as to monitor the role of the mentioned parameters on the targeted properties in the product.     

An auditory illusion predicted from a weighted cross-correlation model of binaural interaction.

In humans, the lateral movement of an acoustic source produces dynamic changes in the relative sound-pressure level and time of arrival of the acoustic wave at the 2 ears. The dynamic nature of these cues is assumed to play an important role in the perception of lateral motion. A phenomenon of auditory motion is reported whose lateral direction and relative velocity may be specified while interaural differences are kept constant. The stimulus producing this percept is a narrowband waveform whose instantaneous bandwidth is a cosine function of time. This phenomenon is predicted from a model of cross-correlation that estimates the running position of an image from a weighted combination of 2 variables: (a) magnitude of interaural delay, with smaller delays receiving more weight, and (b) consistency of interaural information across frequency. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

PEMFC catalyst layers: the role of micropores and mesopores on water sorption and fuel cell activity

The effects of carbon microstructure and ionomer loading on water vapor sorption and retention in catalyst layers (CLs) of PEM fuel cells are investigated using dynamic vapor sorption. Catalyst layers based on Ketjen Black and Vulcan XC-72 carbon blacks, which possess distinctly different surface areas, pore volumes, and microporosities, are studied. It is found that pores <20 nm diameter facilitate water uptake by capillary condensation in the intermediate range of relative humidities. A broad pore size distribution (PSD) is found to enhance water retention in Ketjen Black-based CLs whereas the narrower mesoporous PSD of Vulcan CLs is shown to have an enhanced water repelling action. Water vapor sorption and retention properties of CLs are correlated to electrochemical properties and fuel cell performance. Water sorption enhances electrochemical properties such as the electrochemically active surface area (ESA), double layer capacitance and proton conductivity, particularly when the ionomer content is very low. The hydrophilic properties of a CL on the anode and the cathode are adjusted by choosing the PSD of carbon and the ionomer content. It is shown that a reduction of ionomer content on either cathode or anode of an MEA does not necessarily have a significant detrimental effect on the MEA performance compared to the standard 30 wt % ionomer MEA. Under operation in air and high relative humidity, a cathode with a narrow pore size distribution and low ionomer content is shown to be beneficial due to its low water retention properties. In dry operating conditions, adequate ionomer content on the cathode is crucial, whereas it can be reduced on the anode without a significant impact on fuel cell performance.     

Improved antifouling resistance of electrochemical water quality sensors based on Cu2O-doped RuO2 sensing electrode

Improvement in both sensor's characteristics and antifouling resistance has been achieved by utilising Cu₂O as a dopant to the sub-micron-sized RuO₂ sensing electrode (SE) of the water quality sensors. 20 mol% Cu₂O-doped RuO₂-SE has exhibited a linear response to dissolved oxygen (DO) between 0.5 and 8.0 ppm at various temperatures with the sensitivity slope of −46 mV/decade. This paper describes the structural properties and characteristics of thin-film Cu₂O-doped RuO₂-SE subjected to a field trial in sewerage environment for three months. Selectivity measurements revealed that the presence of PO₄³⁻, SO₄²⁻, Ca²⁺, Mg²⁺, Li⁺, NO³⁻, F⁻, Na⁺, K⁺ and Cl⁻ in the test solution had no significant effect on the sensor's emf. Long-term stability test in harsh sewerage environment demonstrated that the Cu₂O-doped RuO₂-SE possesses improved antifouling resistance compared to RuO₂-SE. Morphology and crystalline structure of Cu₂O-doped RuO₂-SE were studied by scanning electron microscopy (SEM), X-ray diffraction (XRD) technique and Raman spectroscopy.     

Generalized uncertainty principle and the Ramsauer-Townsend effect

The scattering cross-section of electrons in noble gas atoms exhibits a minimum value at electron energies of approximately 1 eV. This is the Ramsauer-Townsend effect. In this letter, we study the Ramsauer-Townsend effect in the framework of the Generalized Uncertainty Principle.     

Application of soft granulation theory to permeability analysis

In this paper, information granulation theory is applied to the design of rock engineering flowcharts. Firstly, an overall flowchart based on information granulation theory has been proposed. Information granulation theory, in crisp (non-fuzzy) or fuzzy format, can take into account engineering experiences (especially in fuzzy shape—incomplete or/and superfluous information), or engineering judgments, in each step of design procedure, while the suitable modeling instruments are employed. In this manner and to extension of soft modeling instruments, using combinations of self-organizing map (SOM), neuro-fuzzy inference system (NFIS) and rough set theory (RST) crisp and fuzzy granules, from monitored data sets are obtained. The main underlined core of our algorithms is balancing of crisp (rough or non-fuzzy) granules and sub-fuzzy granules, within non-fuzzy information (initial granulation) upon the “open–close iterations”. Using different criteria on balancing best granules (information pockets) are obtained. The method has been illustrated on a data set of in-situ permeability measurements in rock masses in Shivashan dam, Iran.     

Aqueous synthesis of interconnected ZnO nanowires using spray pyrolysis deposited seed layers

Interconnected ZnO nanowires were grown in a two-stage process, using spray pyrolysis deposited ZnO seed layers as a nucleation platform for subsequent hydrothermal growth. We present a comparison between the effect of these spray pyrolysis deposited seed layers and well-ordered sputter deposited seed layers, along with their respective ZnO nano-morphologies that were obtained via hydrothermal growth. It will be shown that the growth of interconnected ZnO nanowires was influenced by the physical and crystallographic orientations of the underlying seed crystallites. Sputtered seed layers resulted in fairly vertical nanorods which were approximately 80 nm in width, while seed layers deposited by spray pyrolysis resulted in arrays of interconnected ZnO nanowires measuring approximately 15 nm in width.     

Dynamic fixation and active perception

Fixation is the link between the physical environment and the visual observer, both of which can be dynamic. That is, dynamic fixation serves the task of preserving a reference point in the world, despite relative motion. In this respect, fixation is dynamical in two senses: in response to voluntary changes of fixation point or attentive cues-gaze shiftings, and in response to the desire to compensate for the retinal slip-gaze holding.The work presented here, addresses the vergence movement and preservation of binocular fixation during smooth pursuit. This movement is a crucial component of fixation. The two vergence processes, disparity vergence and accommodative vergence, are described; a novel algorithm for robust disparity vergence and an active approach for blur detection and depth from defocus are presented. The main characteristics of the disparity vergence technique are the simplicity of the algorithm, the influence of both left and right images in the course of fixation and the agreement with the fixation model of primates. The major characteristic of the suggested algorithm for blur detection is its active approach which makes it suitable for achieving qualitative and reasonable depth estimations without unrealistic assumptions about the structures in the images.The paper also covers the integration of the two processes disparity vergence and accommodation vergence which are in turn accomplished by an integration of the disparity and blur stimuli. This integration is accounted for in both static and dynamic experiments.