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In this study an agar/gelatin bilayer film was produced from agar and gelatin monolayers using the casting method in two phases. Then, the characteristics of this bilayer film, including water vapor permeability (WVP), water solubility, water absorption, mechanical and optical properties were compared with those of monolayer films. The results showed that  WVP of the bilayer film (3.25×10^-10 g/msPa)  was significantly lower than the agar (3.90 × 10^-10 g/msPa), and gelatin (4/32×10^-10 g/msPa). Absorption of UV light by bilayer film was significantly higher than the single-layer agar and gelatin films. Although the tensile strength of the bilayer film (10.8 MPa) was higher than the single-layer gelatin (2.86 MPa), it was lower than the single layer of agar film (30.49 MPa) (P<0.05). In conclusion, some properties of agar and gelatin films can be improved by making bilayers film of both biopolymers. 

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In this study two film-forming formulations were prepared. First one was prepared by slowly adding 5gr of sodium alginate & 45gr of dextrose monohydrate in 270ml of distilled water which constantly stirred. Second formulation was as the firs one, but we substituted dextrose monohydrate by maltodextrine and added 20gr glycerol in 210ml distilled water. 50cc film solutions were extended on the 30*40cm polexy glass plates which covered by polyethylene selofan. Films dried after 45h in 23±2˚c & RH50±5%. The dried film layers were immersed for 30" in second solution that was prepared by slowly adding 2.74gr of calcium choloride & 0.9gr of carboxy methylcellulose in 49ml of distilled water which constantly stirred. Film thickness was measured using a digital micrometer at a 0.001mm accuracy. Mechanical properties including tensile strength (TS) and elongation at break (E) were evaluated by a Instron Machin (Zwick, ModelZ 2.5). Results had no statistical significant differences between 2 film formulations. Physical properties including WVP (Water Vapor Permeability) & OTR (Oxygen Transformation Rate) were measured. WVP results had no statistical significant differences between 2 film formulations but OTR in second formulation had a significant decrease. Finally, by all aspects like decrease moisture loss, lipid & myoglobin oxidation, volatile compounds loss and volatile compounds absorb during storage, we recognize second film formulation as a suitable one.

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Concrete properties are dependent on many parameters such as ingredients, production and technology, construction methods and curing conditions that have made concrete as a complex and unpredictable material. But these are virtually ignorable against its precious advantageous and precise studies on above parameters may help us to produce concretes with our desirable properties. Ingredients are of those important parameters that play an essential role. Therefore it is seriously important to have enough knowledge about ingredients, their combined effects and interactions and also effects of their properties on concrete properties. Pozzolan materials can help us to achieve desirable characteristics of concrete and develop its mechanical and physical parameters, hence they are used widely. Improvement of mechanical parameters, permeability reduction, and durability increase are among their fabulous benefits of application. They are deemed as essential ingredients of high durable and strength concretes. Pozzolan weighted ratio is major parameters which develop a homogenous and united medium and improve the physical and mechanical parameters of concrete. The effects of pozzolan on physical and mechanical properties of concrete, moreover it’s specifications, depend on the parameters of other ingredients, such as type of aggregates, particle size distribution of aggregates, fineness modulus of fine aggregates, water-cement ratio, cement type and ect. Then study of combined effects of pozzolan specifications and parameters of other ingredients is inevitable for achieving to a concrete with ideal parameters. As we know, microsilica is the most popular pozzolan material which is used widely and it’s parameters and other ingredients parameters (such as type of aggregates, particle size distribution of aggregates, fineness modulus of fine aggregates, water-cement ratio, cement type and ect) have combined effects on the variation of concrete physical and mechanical parameters. So, in this study we selected microsilica as a pozzolan to determine the combined effects of its weighted ratio content, fineness modulus of fine aggregates and water-cement ratio on physical and mechanical properties of concrete. In this study, the combined effects of microsilica weighted ratio content, fineness modulus and water-cement ratio on physical and mechanical properties of concrete were investigated. For determination the effects of microsilica weighted ratio content on concrete parameters in different water-cement ratios and particle size distributions, 5 different microsilica weighted ratio contents, 3 water-cement ratios and 3 particle size distributions, were selected and totally 45 mix designs were prepared and subjected to slump test and compressive strength, tensile strength and modulus of elasticity tests. Obtained results show a direct relationship between microsilica weighted ratio content and physical and mechanical properties of concrete. Increase in microsilica content from 0% to 10 % in all water-cement ratios and fineness modulus, leads to slump decrease and mechanical parameters increase, while from 10 % to 20 % of microsilica content, mechanical properties fall down, but the reduction trend of slump continues. Also it can be seen that the effect of different weighted of microsilica, on physical and mechanical properties of concrete, reduces by increasing in water-cement ratio and intensifies with increment of fineness modulus of fine aggregates.

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The aim of this study was to explore the minimum amount of urea formaldehyde (UF) resin content and optimum particleboard density while maintaining boards’ quality to reduce production costs. Board density at three levels (520, 620 and 720 kg m^-3) and resin content (6, 7 and 8%) were variable parameters. Stepwise multivariate linear regression models were used to evaluate the influence of board density and resin content on board properties and to determine the most effective parameter. In order to obtain the optimum board density and minimum resin content, contour plots were drawn. Regression models indicated that both board density and resin content were included in Modulus of Rupture (MOR) and Modulus of Elasticity (MOE) models based on the degree of their importance. Internal Bond (IB) model only had one step and resin content positively affected it. The results obtained from contour plots revealed that manufacturing poplar particleboards with density ranging from 600 to 650 kg m^-3 and 6% resin would result in boards with mechanical properties within those required by the corresponding standard. Thickness swelling (TS) values were slightly higher (poorer) than the requirements. The panels required additional treatments such as using adequate amount of water resistant materials to improve thickness swelling after 2 and 24 hours of immersion.