Optimization of Xanthan Gum/Poly(acrylic acid)/Cloisite 15A Semi-IPN Hydrogels for Heavy Metals Removal

Journal of Polymers and the Environment - Semi-interpenetrating networks (semi-IPNs) of Xanthan gum/poly (acrylic acid) containing Cloisite 15A were prepared via radical polymerization using a...     

Adaptation of maize to climate change impacts in Iran

Adaptation is a key factor for reducing the future vulnerability of climate change impacts on crop production. The objectives of this study were to simulate the climate change effects on growth and grain yield of maize (Zea mays L.) and to evaluate the possibilities of employing various cultivar of maize in three classes (long, medium and short maturity) as an adaptation option for mitigating the climate change impacts on maize production in Khorasan Razavi province of Iran. For this purpose, we employed two types of General Circulation Models (GCMs) and three scenarios (A1B, A2 and B1). Daily climatic parameters as one stochastic growing season for each projection period were generated by Long Ashton Research Station-Weather Generator (LARS?WG). Also, crop growth under projected climate conditions was simulated based on the Cropping System Model (CSM)-CERES-Maize. LARS-WG had appropriate prediction for climatic parameters. The predicted results showed that the day to anthesis (DTA) and anthesis period (AP) of various cultivars of maize were shortened in response to climate change impacts in all scenarios and GCMs models; ranging between 0.5 % to 17.5 % for DTA and 5 % to 33 % for AP. The simulated grain yields of different cultivars was gradually decreased across all the scenarios by 6.4 % to 42.15 % during the future 100 years compared to the present climate conditions. The short and medium season cultivars were faced with the lowest and highest reduction of the traits, respectively. It means that for the short maturing cultivars, the impacts of high temperature stress could be much less compared with medium and long maturity cultivars. Based on our findings, it can be concluded that cultivation of early maturing cultivars of maize can be considered as the effective approach to mitigate the adverse effects of climate.     

Bio-based composites from waste agricultural residues

The main objective of this research was to study the potential of waste agricultural residues such as sunflower stalk, corn stalk and bagasse fibers as reinforcement for thermoplastics as an alternative to wood fibers. The effects of two grades (Eastman G-3003 and G-3216) of coupling agents on the mechanical properties were also studied. In the sample preparation, one level of fiber loading (30 wt.%) and three levels of coupling agent content (0, 1.5 and 2.5 wt.%) were used. For overall trend, with addition of both grades of the coupling agents, tensile, flexural and impact properties of the composites significantly improved, as compared with untreated samples. In addition, morphological study revealed that the positive effect of coupling agent on interfacial bonding. The composites treated with G-3216 gave better results in comparison with G-3003. This could be caused by the high melt viscosity of G-3003. In general, bagasse fiber showed superior mechanical properties due to its chemical characteristics.     

Environmental assessment of RAMseS multipurpose electric vehicle compared to a conventional combustion engine vehicle

The RAMseS project, financed by the European Commission under the 6th framework Program, has the purpose of developing a solar powered agricultural vehicle in order to replace the conventional vehicles based on internal combustion engines (ICE). In the present study, we report a comparison of life-cycle emission between two systems; a conventional ICE vehicle (ICEV) and the RAMseS electrical vehicle (EV). The study has been conducted by designing a specific model and using the SimaPro software. The results show that the RAMseS system is considerably more environmentally friendly than conventional ICE based system and that, specifically, it can avoid the emission of about 23 ton of CO_2equ per year. Regarding all other pollutants, we found that the RAMseS system is 2.6 times more efficient than the ICEV. The main contribution to emissions of the RAMseS system is due to the batteries which contribute for a 73% of the total. Therefore, further improvement can be obtained with the use of more advanced battery systems, not based on lead.     

Prediction of methanol loss in vapor phase during gas hydrate inhibition using Arrhenius-type functions

Gas hydrate formation in natural gas and NGL systems can block pipelines, equipment, and instruments, restricting or interrupting flow leading to safety hazards to production/transportation systems and to substantial economic risks. The amount of hydrate inhibitor to be injected not only must be sufficient to prevent freezing of the inhibitor water phase, but also must be sufficient to provide for the equilibrium vapor phase content of the inhibitor. The vapor pressure of methanol must be high enough so that significant quantities will vaporize. Therefore to estimate methanol vaporization losses, it is necessary to develop a new predictive tool. In this work, a simple correlation, which is a mathematically compact and reasonably accurate equation containing few tuned coefficients, is presented here for the prediction of methanol vaporization loss and vapor pressures of aqueous methanol solutions as a function of temperature and methanol mass fraction in aqueous solutions using a novel and theoretically meaningful Arrhenius-type asymptotic exponential function and Vandermonde matrix. The proposed correlation predicts the vapor pressures of aqueous methanol solutions for temperatures up to 100 °C and methanol vaporization loss for temperature between ?16 and 16 °C. Estimations are found to be in excellent agreement with the reliable data in the literature where the average absolute deviation from data is less than 1.5%. The tool developed in this study can be of immense practical value for the engineers and scientists to have a quick check on the methanol vaporization loss and vapor pressures of aqueous methanol solutions at various conditions without opting for any experimental measurements. In particular, chemical and process engineers would find the approach to be user-friendly with transparent calculations involving no complex expressions.