Design, manufacture and evaluation of a new and simple mechanism for transmission of power between intersecting shafts up to 135 degrees (Persian Joint)

This paper introduces a new mechanism which is designed for the transmission of power between two intersecting shafts. The mechanism consists of one drive shaft and one driven shaft, six guide arms, and three connecting arms. The intersecting angle between the input shaft and the output shaft can be varied up to 135° while the velocity ratio between the two shafts remains constant. The research also includes a kinematic analysis and a simulation using Visual NASTRAN, Autodesk Inventor Dynamic and COSMOS Motion. The softwares showed that this mechanism can transmit constant velocity ratios at all angles between two shafts. By comparing the graphs of analytical analysis and simulation analysis, validity of equations was proved. Finally, by fabrication and evaluation of the mechanism it was shown that this mechanism can transmit constant velocity practically.     

Preparation and characterization of novel derivatives of chitosan and trimethyl chitosan conjugated with dipeptides and vitamin B12 as candidates for oral delivery of insulin

Chitosan and its derivatives are widely used in drug delivery systems due to their bio-degradebility, bio-compatibility and absorption enhancing properties. Many peptide and protein derived therapeutics cannot be administered through oral rout because of the proteolytic condition of gastro-intestinal tract and their low bio-availability. Insulin is a peptide drug which is widely used in diabetics as repeated daily injection. Due to the fact that there are receptors for didpeptides and vitamine B12 in small intestine, in this research work novel derivatives of chitosan and trimethyl chitosan conjugated with glycyl-glycine, alanyl-alaninie and vitamine B12 were synthesized and characterized. The structure of conjugates as well as substitution of different functional groups was confirmed by different instrumental analytical methods such as Fourier transform infrared, magnetic resonance, and X-ray diffraction spectroscopy. Nano-particles of aforementioned loaded with insulin were prepared and their size, surface electrical charge and morphology characterized and their release profile were studied. The results are promising and reveal that these new chitosan and trimethyl chitosan derivatives are potential vehicles for protein and peptide drug molecules.     

Assessment of immobilized cell reactor and microbial fuel cell for simultaneous cheese whey treatment and lactic acid/electricity production

Two biological methods for treatment of cheese whey and concentrated cheese whey were investigated in this research. As the first method, fermentation of cheese whey for production of lactic acid, in an immobilized cell reactor (ICR) was successfully carried out. The immobilisation of Lactobacillus bulgaricus was performed by the enriched cells cultured media harvested at exponential growth phase. Furthermore, the FTIR analysis has been done to prove the production of lactic acid. The COD removal during the continuous process for both whey and concentrated whey was above 70% which showed the capability of reaction for wastewater treatment. The cells were immobilised by sodium alginate as a perfect polymer in this regard. The maximum produced lactic acid from whey was 10.7 g l^?1 at 0.125 h^?1 and 19.5 g l^?1 from concentrated whey at 0.063 h^?1. Finally it can be concluded that the process is efficient for lactic acid production and COD removal simultaneously. As the second studied method, whey and concentrated cheese whey were used as the sources of carbon in a microbial fuel cell. The power densities of 188.8 and 288.12 mW m^?2 were recorded for whey-fed and concentrated whey-fed MFCs while the COD removal were 95% and 86% respectively. Biological wastewater treatment can be a very efficient alternative for traditional wastewater treatment which selecting any and or integrating of them depends on specific applications needed to be achieved.     

Effect of Silane-Coupling Modification on the Performance of chitosan-poly vinyl Alcohol-Hybrid Scaffolds in Bone Tissue Engineering

Silicon - Biocompatibility and biodegradability characteristics of some polymers make them an excellent candidate to fabricate porous scaffolds for tissue engineering applications. However, the...     

Cloud Point-Dispersive Liquid–Liquid Microextraction for Extraction of Organic Acids from Biological Samples

A new method combining cloud point extraction (CPE) with dispersive liquid–liquid microextraction (DLLME) named “cloud point‐dispersive liquid–liquid microextraction (CP‐DLLME)” was presented in this work for the first time for the determination of organic acids as model compounds in biological samples using high performance liquid chromatography and UV detection (HPLC–UV). Water (disperser solvent) containing tert‐octylphenol ethoxylate (7.5EO) as extraction solvent, was rapidly injected into a warmed sample solution and cloudy state formed immediately. After that, phase separation was performed by centrifugation. The surfactant‐rich phase was diluted with acetonitrile and injected into a HPLC–UV apparatus. The influence of several important parameters on the extraction efficiencies was evaluated. Under optimized experimental conditions, the calibration graphs were linear in the range of 0.06–1,500 µg L^?1 for target analytes. Coefficient of determination (r²) ranged from 0.9985 to 0.9994. The limits of detection were in the range of 0.05–17.1 µg L^?1. The new method was successfully applied with satisfactory results for analysis of target analytes in spiked samples. The relative mean recoveries of the spiked samples ranged from 91.8 to 107.1 % with relative standard deviations in the range of 2.1 to 4.3 %.     

Spam query detection using stream clustering

Nowadays, search engines play a gateway role for users to access their needed information in the Web. However, malicious users can also use them to facilitate their attacks by submitting excessive amounts of bot-generated queries, called spam queries. In this paper, we propose a novel semi-supervised method which can effectively detect spam queries in a practical manner. We first train a model to characterize normal and malicious users, using the linguistic properties of queries as well as the behavioral characteristics of users and IP addresses. Then, we use the trained model to predict the label of arriving requests with a fast and efficient algorithm which works based on the stream clustering approach. The results of our evaluation with the real log of a local search engine show that the proposed algorithm yields an accuracy of about %94, while incurring a low response-time and memory overhead.     

Investigation on performance of microbial fuel cells based on carbon sources and kinetic models

Substrate concentration has great influence on the electrical performance of a microbial fuel cell (MFC). In this study, date syrup with a high sugar content and diversified types of nutrients was used as a substrate in a dual‐chambered MFC. The results obtained were compared with glucose as a conventional substrate for power generation. A pure culture of Saccharomyces cerevisiae was used as a biocatalyst in the anode chamber and potassium ferricyanide as an oxidizing agent in the cathode side. Maximum power density of 65 mW/m² was obtained in an MFC operated with date syrup at an equivalent total carbohydrate content of 6 g/l. When the electron acceptor in the cathode side was replaced with potassium permanganate, power density was increased almost 2.5‐fold and reached 234 mW/m². The system was loaded with low to high concentrations of sugar (1–7, 10, 20 and 30 g/l). However, at high concentrations of substrates, an inverse relationship with the MFC electrical performance was observed, which was most probably due to substrate inhibition in the MFC. Substrate inhibition models were applied to investigate inhibition kinetic from an electrical point of view. Tessier, Aiba and Haldane as inhibition models were well fitted with experimental data (R² = 0.98–0.99). The tested models revealed that the inhibitory effect for the substrate can be described in terms of model parameters. In order to evaluate the effect of the concentration of substrates on electrical performance, different inhibition concentrations were suggested by the models with respect to electrical responses achieved in the MFC. Copyright © 2012 John Wiley & Sons, Ltd.     

Preparation,characterization and photochemical degradation of dyes under UV light irradiation by inorganic–organic nanocomposite

An inorganic–organic nanocomposite consisting of 12-tungstophosphoric acid (H₃PW₁₂O₄₀) supported on Polyaniline (PANI) has been successfully synthesized by one-step and two-step methods. X-ray diffraction, Fourier-transformed infrared spectroscopy, scanning electron microscopy and electronic absorption spectroscopy indicated that the Polyphosphotungstate (PPT) was chemically attached to the PANI support; the primary Keggin structure remained intact. The photocatalytic and sonocatalytic activity of PPT/PANI was tested by degradation of organic dyes such as Methylene Blue, Rhodamin B, Bromothymol Blue, Methyl Orange and Nylosan Black 2-BC in aqueous solution; the nanocomposite showed higher photocatalytic and sonocatalytic activity than pure polyphosphotungstate or pure PANI.     

Application of ANN and RSM techniques for modeling electrospinning process of polycaprolactone

Neural Computing and Applications - Due to increasing application of nanofibers in many research fields, comprehensive knowledge of the electrospinning process as the most popular method of fiber...