Showing papers by "Mehdi Ardjmand published in 2013"

Lignocellulosic biomass to bioethanol, a comprehensive review with a focus on pretreatment

Abstract: Pretreatment technologies are aimed to increase enzyme accessibility to biomass and yields of fermentable sugars. In general, pretreatment methods fall into four different categories including physical, chemical, physico-chemical, and biological. This paper comprehensively reviews the lignocellulosic wastes to bioethanol process with a focus on pretreatment methods, their mechanisms, advantages and disadvantages as well as the combinations of different pretreatment technologies. Moreover, the new advances in plant “omics” and genetic engineering approaches to increase cellulose composition, reduce cellulose crystallinity, produce hydrolases and protein modules disrupting plant cell wall substrates, and modify lignin structure in plants have also been expansively presented.

Comparison of different ionic liquids pretreatment for barley straw enzymatic saccharification

Abstract: Recently, application of ionic liquids due to their special solvency properties as a promising method of pretreatment for lignocellulosic biomass has received much attention Chemical stability, temperature stability, non-flammability, low vapor pressure, wide liquidus range, and non-toxicity are among those unique properties These solvents are also known as green solvents due to non-toxicity and low vapor pressure The present study was set to compare the effect of five different ionic liquids namely, 1-ethyl-3-methyl imidazolium acetate, 1-ethyl-3-methyl imidazolium diethyl phosphate, 1-butyl-3-methyl imidazolium chlorides, 1,3-dimethyl imidazolium dimethyl phosphate, and 1-butyl-3-methylimidazolium-trifluoromethane sulfonate on barley straw in bioethanol production process The performance of ionic liquids was evaluated based on the change observed in chemical structure, crystallinity index, and cellulose digestibility Overall, 1-ethyl-3-methyl imidazolium acetate was found most effective in pretreating barely straw for bioethanol production To the best of our knowledge, the present study reports different ionic liquids; some for the first time, for barely straw pretreatment

Utilization of constructional lime as heterogeneous catalyst in biodiesel production from waste frying oil

Abstract: Waste frying oil as valueless material which is disposed to environment can be used as a promising feedstock to produce biodiesel. In this study, constructional lime was used as alkaline heterogeneous catalyst for biodiesel production from virgin and waste frying oil. After determining the best activation temperature for the catalyst (600 °C), transesterification reactions were carried out at 65 °C, MeOH to oil molar ratio of 12:1, and 1 wt% of activated constructional lime under vigorous mixing for 5 h. Yield of reactions for virgin and waste frying oil (2.17 % free fatty acid) and pretreated waste frying oil (0.918 % free fatty acid) were 87, 93.9, and 94 %, respectively. Transesterification of virgin frying oil and pretreated waste frying oil were done at 65 °C, MeOH to oil molar ratio of 6:1, and 1 wt% of KOH as catalyst under vigorous mixing for 2 h, for comparison. Yield of the reaction was 98.6 and 95.1 %, respectively. Therefore, when constructional lime is used as catalyst pretreatment of waste oil is not necessary.

Artificial Neural Networks Modeling of Release of Olanzapine From Glycerol Monooleate Matrices

Abstract: SUMMARY The main major of this project was employed the artificial neural networks (ANNs) to create a model to prediction of drug release and to optimize the controlled release formulation of controlled release mechanism of Olanzapine by using Glycerol monooleate (GMO) and Poly ethylene glycol (PEG) as plasticizer to determine the effects independent variable on responses. The weight ratio GMO/Water (w/w) and weight ratio PEG (300)/GMO (w/w) and percentage of Olanzapine (OZ) as independent variables and dependent variables consists of particle size, entrapment efficacy, maximum percentage of release and accuracy of prediction data were assayed by the mean squared error (MSE) or root mean squared error (RMSE). The ability and suitability of all algorithms were in the order of: LM>BR> GD> BFGS INTRODUCTION Artificial neural networks (ANNs) is a learning system relied on a computational method that can simulate the neurological accomplishing ability of the human brain and can design a best fitting and model based on a non-linear relationship between independent factors and pharmaceutical responses by means of iterative training of data and optimization of the results to reduce the network error. The artificial neural networks have been successfully used to different media of pharmaceutical or medical science in recent years (1-2). The ANNs may be used for optimization and control and modeling process and it designed an internal model based on relationships between databases. Artificial neural networks obtained much interest and application in controlled release to predict the structure and optimal condition, and to overcome limitation of traditional statistical techniques and the responses of development in recent years contains of ; the parallel processing which resulted feasible usage and good capability of generated models also have the potential to solve the complex process (3). ANN models employed to generate appropriate regression and performance with negligible error in very short time. The ANNs used to predict the optimum concentration of a fatty alcohol for formulating a stable O/W emulsion and to generate suitable formulation with correlation coefficient 0.9445, by testing various network topology and changes of parameters (4). EXPERIMENTAL METHODS The Matlab software was applied to simulate the model and to investigate the effect of variables on responses. In this study, a feed forward network, type of multi layer ANN as shown in Fig.1, was considered for the prediction of entrapment efficacy, particle size and maximum release of drug in gel system. At first, input and output data were restricted in rang of 0 to 1 and normalized so that we have prevented the removal of small values compared to large quantities. From the prepared gels, 12 of the individual sets of substances were selected as training data set to train the network and the remaining data set were applied as testing data set to check the accuracy and quality of generated model. Fig.1. Feed-forward artificial neural networks First experiments with some initial estimation and different algorithms were implemented and their performances were studies as follows:

Kinetic, Isotherm Study of Nickle Adsorption from Colored Wastewater Using Polypyrrol/ Polyvinyl Alcohol Composite

Abstract: 2 Abstract: Recent project deals to study the adsorption of Ni ions from colored wastewater using adsorbents composite polypyrrol based on polyvinyl alcohol. These experiments were conducted in a batch system. Identification of the synthesized adsorbents was performed by SEM (Scanning Electron Microscope) & FTIR (Fourier transform infrared). Effect of the experimental parameters pH, contact time and dose of adsorbent base on the surface adsorption of colored wastewater has been studied. According to results, optimum pH fo r absorption of Ni by mentioned absorbent was 3. Absorption increased with increasing contact time and after 14 min reached to equilibrium state. Optimum dose of adsorbents has been reported 0.4 grams. The obtained equilibrium data in the initial concentration of Ni in the studied temperature range has a good adaptation with Freundlich isotherm. Evaluation of experimental data Indicated that the surface adsorption of Ni follows the pseudo-second order equation. Conducting polymer matrices provide an interesting polymerization of pyrrole in the presence of organic or and useful focus for expansion of the fields of polymeric inorganic substances. Other useful approach for the reagent research and molecular engineering. They are improvement of the processability and the mechanical electrically conductive which makes their use as meta l properties of insoluble polymers is the blending with replacement materials of some interest. Conductive soluble matrix polymers. Blending is an important electro-active polymers such as polypyrrole (PPy) process for developing industrial applications o f possess some unique chemical and electrochemical polymeric materials and compatibility among components properties. PPy is attractive as an electrically conducting has a marked influence on the resulting physical polymer because of its relative ease of synthesis. properties of polymer blends (7). Blending improves the Bulk quantities of PPy can be obtained as fine powders mechanical and thermal properties of the individual using the oxidative polymerization of the monomer by polymer.Poly(vinyl alcohol) is a non toxic, water soluble, selected transition metal ions in water or various other synthetic polymer with its excellent film forming solvents (1-3). The insolubility in common solvents and properties. While PVA itself has poor metal ion binding infusibility of conducting polymers, in general, make capacity, sorption properties of PVA can be enhanced them poorly processable either by solution technique or by grafting with suitable binding sites. PVA is cheap and by melt processing methods (4, 5). Improvement of these its physic- chemical properties can be enhanced b y material properties can be achieved either by formin g simultaneous cross- linking and grafting. The removal of copolymers of pyrrole, or by forming PPy composites or toxic heavy metals such as cadmium, copper, lead, nickel, blends with commercially available polymers or inorganic mercury and zinc from aqueous environment has received materials which offer better mechanical and optical considerable attention in recent years due to their toxicity route for creating PPy composites is the in situ