Preparation of hydrophilic dimethyl 5‐sodium sulfoisophthalate/poly(ethylene terephthalate) nanofiber composite membranes for improving antifouling properties

In this study, the effect of dimethyl 5‐sodium sulfoisophthalate (SSI) nanoparticles (NPs) on the antifouling properties of poly(ethylene terephthalate) (PET) electrospun nanofiber membranes (ENMs) was investigated through the ultrafiltration of C. I. Basic Blue 3. 3 dye. To reveal the tortuous effect of this additive on the antifouling properties, scanning electron microscopy was used for the characterization of the ENM structure and the optimization of the SSI NP content. Then, some selected physical and structural properties of the membrane, such as the porosity, moisture regain, contact angle, hydraulic permeability (L _p ), and mechanical properties, in the optimized range of SSI NP contents were investigated. Finally, the influence of this additive on the rejection and flux recovery ratio of the prepared membranes was considered. Consequently, the antifouling properties were assessed with consideration of all of the aforementioned parameters. The SSI/PET2 membrane (that with 0.02% w/w SSI NPs with respect to the total amount of PET polymer and SSI NPs), with an average nanofiber diameter of 450 nm, a porosity of 78.44%, a moisture regain of 9.34%, a contact angle of 86.48°, an L _p of 42,167 L h^?1 m^?2 bar^?1, a tensile strength of 4.66 ± 0.04 MPa, a flux recovery ratio of 15.3%, and a final rejection of 95%, showed a significant enhancement in the antifouling properties compared with pristine PET ENMs. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 44522.     

Synthesis and microstructural characterization of low to high molecular weight poly(vinylphosphonic acid)s: effect of molecular weight and temperature on acidity and polyelectrolyte behavior

Poly(vinylphosphonic acid) (PVPA) was synthesized by free radical polymerization of vinylphosphonic acid (VPA) in different solvents. Bromotrichloromethane as a chain transfer agent (CTA) was used in some experiments to control molecular weight of the PVPA. The effects of solvent type and initiator and CTA concentrations on the microstructure, molecular weight and stereoregularity of the resulting PVPA was extensively investigated by FTIR, ¹HNMR, ³¹PNMR and elemental analysis. Polymers with a number-average molecular weight (M_n) in the range of 1550 to 42,190 gmol^?1 were prepared. High molecular weight PVPA with M_n of 42,190 gmol^?1 was obtained from aqueous solution polymerization of VPA with initiator/monomer molar ratio of 0.16/100 at 80°C. Molecular weight decreased with increasing the concentration of initiator and CTA. ¹HNMR spectra were used to investigate tetrad sequences for the methylene protons of PVPA, from which stereochemical information of the polymer chain was obtained. Tetrad sequences were also calculated by Bernoullian probabilities. Moreover, the percent of head-to-head and tail-to-tail irregularities of the resulting PVPA were obtained to be in the range of 16.6–58% depending on the reaction conditions. The PVPA synthesized in acetic anhydride as a solvent had highest amount of the irregularities due to the high reaction rate, which does not allow controlling the structure. Furthermore, due to the importance of PVPA in the proton exchange membranes (PEMs), the effects of molecular weight and temperature on the acidity and titration behavior of PVPA polyelectrolyte were investigated. It was found that molecular weight has no significant effect on the acidity and dissociation of protons at operational conditions of degree of dissociation lower than 0.5. It was also found that by increasing the temperature, pH values were decreased, meaning that dissociation of protons and consequently the proton conductivity of PVPA membranes can be affected by temperature. Titration behavior of PVPA also showed that the PVPA has a behavior similar to a monoprotic acid.     

Male Aggregation Pheromone of Date Palm Fruit Stalk Borer Oryctes elegans

Laboratory and field investigations were carried out to characterize the chemical communication system of the date palm fruit stalk borer, Oryctes elegans, and to develop pheromone-based trapping in Eastern Iran. Adults of both sexes feeding on date palm pieces attracted conspecifics, whereas date palm alone was minimally attractive. Males were twice as attractive as females. More beetles were captured at the palm crown than at ground level. Odors from adults feeding on sugarcane were sampled and analyzed by gas chromatography and mass spectrometry. Whereas females did not emit sex specific volatiles, males emitted a blend of 4-methyloctanoic acid (1: major component) and ethyl 4-methyloctanoate (2), occasionally mixed with minor components: 4-methyloctanyl acetate (3), methyl 4-methyloctanoate (4), 4-methyloctanol (5), and nonanyl acetate (6). Electroantennography and field trapping experiments demonstrated that compound 1 is an essential component of the male aggregation pheromone of O. elegans. It was barely attractive by itself but synergistic with fresh date palm odor. It attracted many more beetles than any of compounds 2-6. The addition of one or several of compounds 2-6 to 1 did not improve trap captures. During the course of 2 years, we captured 4000 beetles, with a weekly average of 6.3 beetles/trap, and were able to monitor the seasonal flight of O. elegans. Our results provide the basis for developing mass trapping for control of this pest.     

Regionalization of Rainfall Intensity-Duration-Frequency using a Simple Scaling Model

Design storm is one of the most important tools to design hydraulic structures, hydrologic system and watershed management, mostly extracted by intensity- duration - frequency (IDF) curves for a given specific duration and return period. As for conventional methods to calculate IDF curves, the precipitation should be recorded for different durations so that foregoing curves can be extracted. Such data can be collected from rain gauge stations. In many areas, just daily precipitation data are available by which IDF curves cannot be extracted as per conventional methods. The aim of this research is to make IDF curves for short-term durations according to time scaling model as well as daily rainfalls. The relationships of this method are characterized with three variables including mean (μ ₂₄) and standard deviation (σ ₂₄) of daily rainfall intensity, and scaling exponent (H) by which all IDF curves might be drawn. The method used in present paper entails for less computational steps than conventional methods and by far has low parameters considerably than others in turn increases reliability. Scaling method is used to extract the IDF curves in rain-gauge stations in Khuzestan province located in southwest Iran and results proved the efficiency and robustness of the scaling method. Also ability of scaling concept method was examined in constructing of regional IDF.     

Daily Mean Streamflow Prediction in Perennial and Non-Perennial Rivers Using Four Data Driven Techniques

This study examines and compares the performance of four new attractive artificial intelligence techniques including artificial neural network (ANN), hybrid wavelet-artificial neural network (WANN), Genetic expression programming (GEP), and hybrid wavelet-genetic expression programming (WGEP) for daily mean streamflow prediction of perennial and non-perennial rivers located in semi-arid region of Zagros mountains in Iran. For this purpose, data of daily mean streamflow of the Behesht-Abad (perennial) and Joneghan (non-perennial) rivers as well as precipitation information of 17 meteorological stations for the period 1999–2008 were used. Coefficient of determination (R²) and root mean square error (RMSE) were used for evaluating the applicability of developed models. This study showed that although the GEP model was the most accurate in predicting peak flows, but in overall among the four mentioned models in both perennial and non-perennial rivers, WANN had the best performance. Among input patterns, flow based and coupled precipitation-flow based patterns with negligible difference to each other were determined to be the best patterns. Also this study confirmed that combining wavelet method with ANN and GEP and developing WANN and WGEP methods results in improving the performance of ANN and GEP models.     

People tracking using a network-based PTZ camera

In this paper, we propose a method for online upper body tracking using an IP PTZ camera. This type of camera uses a built-in Web server resulting in variable response times when sending control commands. Furthermore, communicating with a Web server involves network delays. Thus, because the camera is inside a control loop, the effective frame rate that can be processed by a computer vision method is irregular and in general low (2–6 fps). Our tracking method has been specifically designed to perform in such conditions. It detects, at every frame, candidate blobs using motion detection, region sampling, and region color appearance. The target is detected among candidate blobs using a fuzzy classifier. Then, a movement command is sent to the camera using the target position and speed. The proposed method can cope with low frame rate, and thus with large motion of the target, even in the case of a fast walk. Results show that our system has a good target detection precision (>88%) and low track fragmentation, and the target is almost always localized within 1/6th of the image diagonal from the image center.     

Effect of gelatin/agar bilayer film incorporated with TiO2 nanoparticles as a UV absorbent on fish oil photooxidation

This research evaluated the effect of gelatin/agar bilayer film and nanocomposites containing different concentrations of TiO₂ nanoparticles (0.5%, 1% and 2%) as ultraviolet (UV) and oxygen barriers on the oxidative stability of fish oil. Samples of fish oil covered with the bilayer films were stored under UV light or in darkness and with or without lids at 18 °C for 12 days. Oil quality in terms of peroxide values (PV), thiobarbituric acid (TBA), conjugated diene (CD), fatty acids profile and colour change (?E) was monitored during storage. Fish oil photooxidation was hindered by increasing TiO₂ concentration, so that nanocomposite containing 2% of the nanoparticles could control photooxidation, similar to the samples stored in darkness. Furthermore, upon studying both photooxidation and autoxidation, the highest amounts of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), as well as the lowest amount of changes in PV, TBA, CD and ?E, were observed in oils covered with the nanocomposites.     

New synthesis processes of polyetheramines: Comparison of three different developed amination routes

In this work, three different novel processes are reported for the preparation of polyetheramines (PEAs) from polyethylene glycols (PEGs) and polypropylene glycols (PPGs). The processes are the nucleophilic substitution, oxidation/reduction, and catalytic aminations. The novelties of the processes lay in environmentally friendly routes, the variety of possible precursors (i.e., PEG and PPG with different molecular weights), and extraction methods. The formation of the PEAs with no chain cleavage was confirmed by nuclear magnetic resonance (NMR) spectroscopy and gel permeation chromatography (GPC) results. Based on the comparison study, the nucleophilic substitution and catalytic aminations were the most efficient (conversion >90%) and shortest (yield >90%) methods, respectively. For nucleophilic substitution, the amination of PEG and PPG intermediates was performed in different solvent media due to the difference in solubility parameters of PEGs and PPGs. The catalytic route (using [Zn(tu)₃]SO₄/aqueous ammonia system) can be considered a green method; however, catalytic amination of the PPGs is impossible due to insolubility of PPGs in aqueous ammonia. Therefore, the oxidation/reduction method using Leuckart reaction appears to be the most environmentally friendly route for the amination of PPGs. Moreover, PEGs and PPGs with different molecular weights showed various behaviors during reaction and separation protocols.