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The effect of various reinforcements on the ablative composites has been discussed in this paper. The ability of phenolic resin to reside a char layer at high temperatures is the main reason to select it as a matrix. Analysis of the physical ablation process of a composite and low thermal conductivity of zirconium oxide is performed to produce Resole/carbon fabrics composites coated with a thin film of zirconium at the back side of the specimens. Different materials, such as carbon fabrics, glass fabrics, and also silica and zirconium powders have been used as reinforcements for synthesis of the composites. The specimens were prepared with three sets of compositions. The first set was produced with 37.5 wt% of Resole and 62.5 wt% of reinforcements. Another set of specimens were produced with 40wt% Resole, 40 wt% of silica and 20 wt% of zirconium. To explore the ablation characteristics of the composites in terms of insulation index, erosion rate and microscopic pattern of ablation, an oxyacetylene torch flame with heat flux of 8.35 Mw/m2 at approximately 3000°C was used. It was found from ablation test that the erosion rates of the Resole/carbon fabric specimens are 20% lower than that of the other specimens. Additionally the high insulation index of the Resole/carbon fabrics coated with zirconium, indicates that these composites are the best ablative materials in the present study. SEM observations show that the thermo mechanical and thermo physical erosion effects are the most important factors that influence the ablation process. The proper adhesion between reinforcements and matrix is important to achieve improved ablative properties.

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Aims: In this study, gelatin was extracted from Siberian sturgeon waste and used in film making.
Materials and Methods: Gelatin was extracted using NaOH and HCl. After evaluating the extracted gelatin properties (bloom grade, pH, zeta test, melting and setting temperature and time), the edible film was prepared by using glycerol.
Findings: The results showed that the extraction efficiency of the gelatin was %20.06. The protein content, pH, degree of gel hardness, setting and melting temperature and time were 79.2 ± 0.6%, 4, 160.2 ± 0.4 g, 13.1 ± 0.2 ° C in 180.3 ± 0.5 seconds and 19.33 ± 0.5 ° C in 140.66 ± 0.5 seconds, respectively. Zeta potential indicated a positive surface charge in gelatin. The thickness, moisture, solubility, tensile strength, tensile strength and permeability tensile strengths properties of gelatin film reported 0.05 mm, %10.2 ± 1.5, %79 ± 3.7, 30.01 ± 0.7 MPa, %77.5 ± 3.6 and 3.5 ± 0 g mm/h mm²kpa×10^-6­, respectively. SEM images of the film showed smooth structure without cracking. Moreover, the FTIR result showed the formation of amide bands in the region of 3277.62, 1633.92, 1530.11 and 1236.49 cm^-1.
Conclusion: Due to the efficiency and properties of gelatin, and the mechanical and physical properties of the edible film, it can be used as a good candidate for the production of biodegradable films in food storage.

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In the present study, the structural and antioxidant properties of fucoidan extracted from macroalgae (Sargassum and Padina) from the Persian Gulf coast were evaluated. The fucoidan was extracted by ethanol and hot water and after calculating the extraction yield, DPPH radical scavenging activity, ferric reducing antioxidant power (FRAP), scanning electron microscopy (SEM), and its monosaccharides by HPLC method were examined. The yield of fucoidan in Sargassum (4.2 ± 0.00%) was higher than Padina (2.98 ± 0.28%) (P < 0.05). The IC50 of DPPH free radical scavenging in fucoidan extracted from Sargassum and Padina were 0.1 and 0.14 mg/ ml, respectively, which were higher than BHT as a commercial antioxidant (P < 0.05). The rate of FRAP in both samples increased with an increase in the concentration of fucoidan. The SEM results showed that fucoidan from both macroalgae had strong structural cohesion and irregular surfaces, but Padina had more surface protrusions. The glucose, mannose and xylose sugars in different amounts were detected by the HPLC method, in which the amount of glucose and xylose sugars were higher in the fucoidan derived-Sargassum (P < 0.05). According to the results of the present study, the fucoidan extracted from the Sargassum and Padina can be a good alternative to an industrial antioxidant in food

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In the recent years the use of phosphate fertilizer has been increased. On the other hand, the use of phosphate fertilizer causes change in micro-structure and geotechnical properties of clayey soils. This may raise the risk for groundwater contamination. The main objective of this paper is to study the permeability and microstructural change of clayey soils after interaction with phosphate fertilizer. To achieve the above mentioned objective, series of geo-environmental engineering experiments was performed and the process of interaction of bentonite with phosphate fertilizer is studied. The evaluation of permeability variations, sedimentation tests, plasticity properties, soil pH variations and results of XRD and SEM experiments show that the presence of phosphate fertilizer changes the clay soil microstructure. Based on the results of this study phosphate fertilizer causes a reduction on the quantity of intensity of basal spacing of montmorillonite. Consequently the permeability might increases around1000 times at the presence of 10 percent phosphate fertilizer.
 

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Abstract:
Background and Objective: Marl soils with their complex behavior can be found in different parts of the world, such as Spain, the United States, Italy, Britain, France, Canada, and the Gulf states. In Iran, also, Marls can be located in abundance in the marginal zones of the East Azerbaijan Province, Persian Gulf, Hormozgan, and Qeshm Island. Marl soils' engineering behavior and durability in dry and wet conditions are entirely different and cause challenges in construction projects. Marl-like soils are widely observed in different parts of the world. The behavioral characteristics of marl typically depend on the distribution and size of the particles and their plastic properties. Under dry conditions, the deformation of marl soil is due to the breakdown of particles and creating a new structure. However, when this type of soil is exposed to moisture, the aggregate bond will degrade and cause swelling in the soil and, at the same time, a change in its hardness and strength on the other hand, many polluting industries are located on marl soils. Usually, the pollution caused by these industries changes the pH and creates acidic and alkaline conditions in marl soils. Therefore, this study aims to study the effect of initial pH on the durability of marl soils from a microstructural perspective.
Materials and methods: In this regard, marl soils with different initial pHs were prepared by adding 1 M sodium alkali hydroxide (NaOH) and hydrochloric acid (HCl). Changes in geotechnical and geoenvironmental characteristics were investigated by macrostructural experiments (Atterberg Limits, permeability, and unconfined compressive strength, durability, and water absorption testing) as well as microstructural experiments (Laser diffraction particle size analysis (PSA), X-ray diffraction (XRD), X-ray fluorescence (XRF), carbonate percentage determination and scanning electron microscopy (SEM) images) and the effect of initial soil pH change on marl engineering behavior was investigated.
Results and discussions: One of the most important results of the present paper is the durability and stability of marl soils with initial pH ≤4 against moisture. Based on the SEM images and XRF analysis results, the formation of magnesium chloride in the structure of palygorskite and sepiolite has caused the stability of marl soils with initial pH≤ 4. Also, the initial strength of marl soil does not affect the durability of indentation.