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Research Subject: Poor mechanical strengths and lack of thermal stabilities of hydrogels confine their extensive practical applications in many areas. The growing scientific need for solving this problem and achievement to the hydrogels with improved properties has led to the design and production of the nanocomposite hydrogels.
Research Approach: The polymeric networks of nanocomposite hydrogels compared to the ordinary hydrogels have improved elasticity and rheological properties. Other points that increase the importance of structural studies of nanocomposite hydrogels are the high strength of these materials versus the application of external forces, as well as maintaining its structure against increasing of temperatures. In this regard, the type and amounts of nanomaterial, the preparation method and formation of hydrogel network have a significant role in improving the physical, chemical and biological properties of hydrogels, and, it must be noted that these parameters will depend on the application of nanocomposite hydrogels. This also highlights the need for the production of nanocomposite tailored hydrogels. Therefore, orientation of the range of nanomaterials, the preparation method and product identification, along with sufficient information on the application of these materials, might have an important role in ensuring the success of these materials, requiring comprehensive library research and studies on polymerization processes, morphology and rheology.
Main Results: In this review article, the scientific advances in the field of nanocomposite hydrogels, focusing on its types based on the type of nanoparticles, its properties, preparation methods, identification methods with a new perspective on rheology, thermal analysis and morphology is investigated. Finally, the applicability of these materials is collected in a comprehensive table in various fields such as tissue engineering, enhanced oil recovery, agriculture, and etc…

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Research subject: Expandable Poly Styrene (EPS) has many applications. This polymer prepared by the radical polymerization. This material has many uses in packaging and insulation industries Some of the properties of this polymer like low mechanical strength caused its applications to be limited. By adding some materials, these properties can be improved. Styrene Butadiene Styrene (SBS) is from the materials that which by adding it to the EPS it can improve its quality.
Research approach: In this research, EPS having different percentages of SBS (0, 0.01, 0.02, 0.03) in different conversion percentages (0.6, 0.63, 0.66, 0.69) has been prepared. Different tests like Impact Test, Modular Melt Flow test, Vicat Softening Temperature test, Tensile at Break test, K-value test, Rochwell Hardness test and Elongation at Break test are done on the prepared polymer. Laboratory gained data has been simulated by Multi-Layer Perceptron (MLP) method of artificial neural networks (ANN) and the simulated data covers the laboratory data perfectly.
Main Results: Investigating the tests show that in constant percentages of SBS in EPS with increase in conversion percentage of EPS, the numerical amount of the tests increases except MFI test (low MFI number means better quality). Increase in SBS percentage in the EPS, increases the properties of polymer. In addition, the results of simulation show that the laboratory data covers the the simulated data perfectly. The data obtained from the results of this reasearch can be used for predicting the data for the points which has not been tested. Adding SBS in different weight percentages of poly styrene in different conversion percentages in order to increase the properties of poly styrene has been used for the first time in this research and the laboratory data results in points which has not been tested has been acquired by applications of ANN.

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The use of recycled materials in Portland cement concrete (PCC) has become more and more popular in recent years. Most recycled materials applied in PCC are used to replace coarse aggregates, fine aggregate, or act as cementitious additives. When using recycled materials in PCC, it is desirable that the properties of the concrete can also be improved. Plain PCC, while typically having high strength, generally possesses very low post failure toughness, which may cause abrupt failure of structures and short pavement life. Reclaimed or recycled asphalt pavements (RAP) have been routinely used in the construction of pavement granular bases and hot-mix asphalt concrete. RAP is the removed and/or processed asphalt pavement materials containing both aged asphalt and aggregates. The asphalt coated on the surface of the aggregates typically forms a film with a thickness between six to nine microns. The use of RAP in PCC, though seems to be a viable solution to improve the toughness, has received little attention by research communities. Cementitious systems incorporating polymers have received considerable inter- national attention, especially over the last 30 years or so. The reason for this interest can be attributed to the improved engineering properties when compared to the unmodified materials, e.g. tensile/flexural strength, toughness and durability, the latter including resistance to carbonation, chloride penetration, and frost damage. Additionally, these systems may be used as repair materials where a good bond with the existing concrete or steel is required. Many polymer concrete combinations are available. Polymer-modified cement mortar and concrete (PMC): polymer particles in the form of a latex or redispersible powder are added to a fresh cementitious mix which is then cured. The most commonly used latexes are aqueous suspensions of styrene- butadiene-rubber (SBR) and various acrylics (Ac) containing 45±50% polymer solids. In SBR, the ratio of styrene to butadiene governs the properties of the polymer, with 60±65% styrene giving a good balance. Higher styrene contents would improve compressive and tensile strengths but reduce adhesion and raise the minimum film-forming temperature (MFT). In this study, the effect of SBR latex and silica fume on the mechanical strength (compressive, bending, and splitting tensile strength, elasticity modulus, toughness index), permeability (water penetration, rapid chloride penetration (RCPT), electrical specific resistivity) and microstructure of concrete made with recycled asphaltic aggregates to replaced with natural coarse aggregate (33%, 66% and 100% by weight) were studied. Results showed that the adding of latex and silica fume significantly increased mechanical strength and decrease permeability of concrete mixes. quality and microstructure of interfacial transition zone (ITZ) between aggregate- cementitious matrix by use of scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy analysis (EDX) was evaluated. SEM images showed that the mixtures containing latex and silica fume had uniform and smooth structure at surface aggregate- cementitious matrix, and also EDX analysis represents reducing the thickness of ITZ and the calcium to silicon ratio. For assessment of latex effect mechanism on compressive strength, three different type of curing on cube mixtures were applied. The results showed that compressive strength of specimens cured at temperatures significantly increased, which indicates of heating- help to formation polymeric membrane in specimens containing latex.

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The aim of this research was to prepare a nanocomposite film based on Barhang (Plantago major L) seed gum. Zinc oxide (ZnO) and cellulose nanofiber (CNF) nanoparticles at the concentrations of 4 and 8% w/w were incorporated for improving the morphological, structural, thermal, water vapor permeability and mechanical properties of films. The FT-IR results confirmed the occurring of new interactions between nanoparticles and mucilage polysaccharides. XRD results indicated that the effect of ZnO on semi-crystalline structure of Barhang film is higher than the effect of CNF. The neat film has a smoth surface, but the roughness increased by addition of nanoparticles. According to TGA results, the thermal stability of films was affected by incorporation of nanoparticles, but the effect of CNF on improving the thermal stability of film was more than ZnO. The addition of nanoparticles at the concentration of 4% had no effect on the thickness of films but by increasing to 8%, the thickness increased. Moisture content and moisture absorption of films was also decreased significantly by incorporation of nanoparticles. The water vapor permeability of films was dependent on the concentration of nanoparticles and at 4%, it decreased significantly but at 8% concentration, the permeability increased again due to the aggregation of nanoparticles and their hydrophilic nature. The water contact angle of films’ surface increased by addition of ZnO but the CNF caused to decrease this value due to its hydrophilicity. The effect of CNF on improving the mechanical properties of films was better than ZnO. The CNF had the most effect on increasing tensile strength, elastic modulus and elongation to break. In general, this research indicated that by using organic and inorganic nanoreinforcements, the improving of the properties of Barhang seed gum based films is possible and the effect of CNF is more than ZnO. 
 

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New surgical technologies are continuously being developed to enhance control during operations and mitigate injuries resulting from surgical procedures. One such advancement is the ultrasonic laparoscopic surgical tool known as the ultrasonic scalpel, which is designed to minimize surgery-related injuries when used alongside conventional tools. Establishing optimal input parameters for this ultrasonic instrument not only enhances operational reliability but also decreases the risk of resultant injuries. Ongoing research investigates the impact of varying power and duration of ultrasonic vibrations, along with the equivalent energy input into the blood vessel during surgery, on tissue mechanical characteristics and thermal effects. This study assesses the ability of sheep carotid artery tissues to withstand blood pressure within the vessel and examines thermal damage through pressure testing and optical imaging. Findings indicate that maintaining constant time at specific power yields maximum pressure tolerance at optimal power levels. However, varying the time at specific power settings produces different effects. For instance, the highest blood pressure resistance, at 1100 mmHg, was observed at 44 Watt of power over a 10 second duration at 10 newton. Furthermore, results demonstrate that increased energy input correlates with heightened thermal damage to surrounding tissues during the operation.