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The unique physicochemical properties of nanoscale plasmonic materials have attracted considerable attention in the fabrication of hybrid nano-bio structures because of their promising applications in biosensing, imaging, and controlled-release drug delivery. The purpose of this study was the synthesis of functionalized gold nanorods (GNRs) to both reduce the toxicity and increase the biocompatibility for further applications such as the design of a therapeutic nanocarrier for nucleic acid delivery to cancerous cells. In this study, GNRs were prepared by seed-mediated method and their surface was modified by polystyrene sulfonate (PSS) polymer. Then, peptide-functionalized GNRs was fabricated via ligand exchange method through the Au-S bond. The CTAB-GNRs and functionalized nanostructures were characterized using ultraviolet-visible spectrophotometry, transmission electron microscopy (TEM), and zeta potential measurement. Finally, the cytotoxicity effects of functionalized GNRs on Hela cells were studied by MTT assay. The optimal concentration of PSS and peptide, which did not cause any aggregation and morphological perturbations of the nanostructure were obtained 50μM and 1mM respectively. The survival percentage of treated Hela cells significantly increased by surface modification of GNRs with PSS and functionalization with peptide compared to CTAB-GNRs. While LC50 of functionalized GNRs was calculated 50nM, treated cells with the same concentrations of CTABGNRs survived less than 20%. Functionalization of GNRs increases its biocompatibility and improves applications of this nanostructure as a therapeutic carrier in cancerous cells.

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Counting the minimum number of differential active S-boxes is a common way to evaluate the security of block ciphers against differential and linear cryptanalysis. In this paper, we use mixed-integer linear programming (MILP)
to calculate minimum number of active S-boxes of the some Feistel structures. We focus on Type-II of Feistel structures
with four and six partitions and explain how to analyze them by MILP when they have more than one MDS2 matrices (like
Clefia) in their structure. Moreover, we propose a new four partitions Feistel structure with three multiple MDS matrices
which have more active S-boxes rather than Clefia structure. We also generalize Clefia structure in to six partitions Feistel
structure by three multiple MDS matrices for 192 bits block size. 

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The study of wave transmission over submerged obstacles and the flow pattern that formed around the obstacle has been always an important subject because of the affect directly on wave and the changes in wave energy that is crucial in the design of devices, which absorb wave’s energy and coastal breakwaters. In this research, the flow pattern induced by solitary wave passing over a submerged vertical thin plate has been studied. A wave maker piston has been used to generate the solitary wave and particle image velocimetry (PIV) technique has been used to flow visualization that this technique is non- introsire optic method, which can measure the fluid velocity with any changes in flow pattern. The study of the flow pattern visualization, velocity values and vorticity shows, at first the flow separation shear layer forms and the clockwise vortex generate at the rear edge of the obstacle before the wave arrives to the barrier. Then the vortex grows in size and cussed the water move upward like vertical jet on upstream. Then the fluid enters to the downstream and generates the counterclockwise vortex in this region, which is less than the first clockwise vortex in power that makes an important difference with the thick geometry researches. In addition, the non-dimensional horizontal components of fluid velocity at the time of shear layer formation at the rear edge of the plate have been studied and it has been compared with the case that the barrier is rectangular.

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In the current research, the effect of severe plastic deformation on microstructure and mechanical properties of Al-7075 alloy focusing on toughness was investigated. For this purpose, the Al-7075 alloy was subjected to ECAP process up to 4 passes by route BC at room temperature. Microstructure and fracture surface of the specimens were analyzed by optical and electron microscopy and mechanical properties were studied by hardness, tensile and impact tests. Dynamic and static toughness of the alloy were measured from the area under the stress-strain curve and impact test, respectively. The experimental data revealed that after 4 passes of ECAP, the grain size decreased from 40 µm to about 600 nm, and the hardness and strength of the specimen increased about 2 times in comparison with initial material. Static and dynamic toughness decreased about 62% and 30% after the first pass of ECAP, respectively. While, by increasing the pass number, the static toughness increased and dynamic toughness remained approximately constant. The fracture surface of specimens revealed that the fracture of all specimens was ductile. ECAP process caused a considerable increase in strength of Al-7075 (more than 100 percent), whereas, the toughness declined slightly during ECAP process (about 30 and 5 percent in dynamic and static toughness, respectively). So, it can be concluded that one the most advantages of ECAP process in comparison with common forming process is the notable improvement of strength without considerable sacrifice of toughness.

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In the last decades, the development of nanotechnology has been rising and nanomaterials have been widely used in combination with many traditional materials. The prominent chemical and physical properties of nanomaterials enable them to play an important role in various applications such as modifying the structure of materials, improving the properties of composites, and manufacturing new multifunctional products. The building industry has not been exempted from this rule. Many studies have been carried out on the effect of nanoparticles on concrete performance and most of them demonstrated the improvement of concrete properties. There are a lot of studies on the effect of nanoclay on cement composites. However, there are little researches on the halloysite nanotube (HNT) effect, as subcategories of nanoclay, on the properties of cement composites. Halloysites are a kind of mineral clay which are often produced by air-induced erosion or by thermal transformation of ultramafic rocks, volcanic glasses, and pumice. They are chemically similar to kaolinite but, unit layers in halloysites are separated by a monolayer of water molecules. In general, halloysites have different shapes and exist in the plate, spherical, and tubular forms. The tubular structure is the dominant form of halloysite in nature. Chemically, the outer surface of the HNTs has properties similar to SiO2 while the inner cylinder core is related to Al2O3. Due to the tubular geometry, HNTs like carbon nanotubes could be classified as one-dimensional nanoparticles. Halloysite can grow into long multi-walled tubules, which morphologically resemble to multi-walled carbon nanotubes. In terms of dimensional characteristics, HNTs have an external diameter of about 30 to 190 nm, an inner diameter of about 10 to 100 nm and a length between 3 to 30 µm. Halloysite characteristics could be sum up as high length to diameter (L/D) ratio, high specific surface, large pore volume, low density in surface, and pozzolanic properties. Mechanical properties of HNTs could make them an ideal reinforcing additive to improve the mechanical properties of cement composites. In addition, due to the nano scale size of HNTs, they can play the role of filler and make a denser and stronger microstructure. Therefore, in this research, the effect of HNTs on the performance of cement mortar was evaluated and the workability and permeability of mortar samples containing 3% halloysite nanotubes were presented. The results indicated an increase of more than 28% of electrical resistance, a decrease of approximately 26% of water absorption rate, 23% reduction in water repellent, a decrease in the workability, and an increment in the rate of hydration of cement mortar due to the incorporation of 3% halloysite nanotube. These results indicate that halloysite nanotubes can be used as an appropriate nanoparticle to improve the properties of cementitious composites. The pozzolanic properties of HNTs enable them to decrease the permeability of cementitious matrices. Silicate of HNTs react with calcium ions of hydrated cement and increase the calcium silicate hydrate gel. This could lead to an enhancement in the durability of cementitious matrices. This paper can provide more insights on the application of nanoparticles with cementitious composites.

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Conventional construction cementitious composites typically contains cement, fine and gravel aggregate and additive in a specific ratio along with water. It is extensively used to bind the structural elements together like the bricks, stones, and concrete blocks, or end connection of the column and beam, and to develop a sufficient bond with the substrate as a repair cementitious composite, due to its several advantages, such as low cost, appropriate compressive strength, and easy access. However, some weaknesses of the cementitious mortar influence its performance under different conditions. For example, low tensile strength, brittle behavior, unacceptable performance against shrinkage cracks, and lack of resistance against stress concentration are some of these critical properties of the mortar, if not modified, the structures will be deteriorated in a short time. These deficiencies emerge from extravagance water, bleeding, plastic settlement, shrinkage stress and strain concentrations due to external limitations. When loads are applied and further increased, type of cracks grow and reach a critical condition, and catastrophic failure is precipitated. In this situation, the mortar will be exposed to severe damaging factors such as premature saturation, disadvantage of freeze-thaw, scaling, and corrosion of steel. In recent years, researchers in the field of concrete technology have focused on the using of a variety of fibers such as carbon, steel, glass, polypropylene and basalt fiber into the cementitious composites to improve their mechanical properties (especially their ductility behavior) and to some extent their durability. Accordingly, in the present study, the hybrid effect of different percentages of basalt and polypropylene fibers on the workability, mechanical behavior and durability properties of cementitious mortar was investigated. Polypropylene fibers are known in the field of reinforced concrete, but basalt fibers are a new potential additive in this field. In recent decades, researchers have studied more about basalt fibers because of their potential reinforcement properties in composite materials. The basalt fibers are an appropriate replacement for another fibers, including glass, steel, and carbon fibers in plenty of applications due to their excellent properties such as high mechanical properties specially tensile strength and flexural strength, good resistance to low and high temperature, low cost, durability, vibration resistance, high elasticity modules, great failure strain, acceptable persistence to chemical assault, impact load and fire with less toxic materials. Samples containing a hybrid composition of 0.05 and 0.125 percent (weight percent of total cement and aggregate) of the basalt and polypropylene fibers have been used in order to evaluate the effect of fibers so that a total of 4 types of mixed designs containing hybrids of basalt and polypropylene fibers were made and its results have been compared with a control sample. As expected, after analyzing the results, the fibers had no significant effect on the compressive strength of the cementitious composite, while the results of this study reported a favorable and remarkable performance of these fibers in increasing flexural and splitting tensile strength, as well as the water absorption of cementitious mortar is favorably decreased by the fiber. The sample containing 0.125% basalt and polypropylene fibers increased flexural and splitting tensile strengths by 28 and 23%, respectively. Also, the sample containing 0.125% basalt fiber and 0.05% polypropylene fibers resulted in 9.3% increase in compressive strength, 24% decrease in sorptivity and 15% water absorption. The results of the current study have shown that the simultaneous use of basalt and polypropylene fibers can improve significantly the mechanical behavior and durability properties of cementitious mortar, whereas according to the previous studies if each of these fibers is used separately, such a desirable result will not be obtained.

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Cementitious composites are mainly used in the construction industry due to their good characteristics such as low cost, acceptable compressive strength, and easy access. However, there are many weaknesses in these materials, including low tensile strength, brittle behavior, and unacceptable durability (service life), which need to be improved to achieve more sustainable constructions. Nowadays, the using of nanotechnology have been growing and nanomaterials have been widely used in compound with a multitude of conventional materials. The outstanding chemical and physical properties of nanomaterials enable them to play a key role in various applications, such as modifying the material structure, ameliorating the properties of the material, and manufacturing modern multifunctional products. Recent advances in nanotechnology have led to produce nano-sized particles that can improve the durability performance of construction materials. Nanoparticles such as nano-silica, nano-Fe₂O₃, nano-clay, carbon nanotube (CNT), nano-Al₂O₃, nano-TiO₂, and graphene oxide have been used to enhance the properties of cementitious composites. The performance of halloysite nanotube on the characteristics of cementitious composites has been studied less than other nanomaterials. Although the positive effects of nanomaterials such as halloysite nanotube (HNT) on the properties of cementitious composites have been proven, the very important issue of the correct and proper dispersion of nanomaterials in the cementitious environment has not been studied acceptably. The high surface energy and interparticle forces, including van der Waals, hydrogen bonding, and electrostatic interactions, make the nanomaterials highly susceptible to agglomeration. The aggregates of nanomaterials not only decrease their benefit but also act as potential weak spots in cementitious composites that can cause stress concentration, therewith diminishing the mechanical properties of cementitious composites. In this regard, the current paper investigated the effective factors on the agglomeration of halloysite nanotube (HNT) in the cementitious alkaline environment. Finally, this paper presented an approach for solving the problem of HNT agglomeration. Results showed that Ca²⁺, K⁺, and Na⁺ ions as alkaline agents of cement environment are the main factors to provide a state for HNT agglomeration. Among them, Ca²⁺ has more effect in agglomeration of halloysite nanotube due to the bridging effect between halloysite particles. From the results, the dispersion of HNT made better with increasing the alkalinity of cement environment until pH=11, while after this pH, the agglomeration of HNT started and the intense of agglomeration raised with the increase of pH, where it reached a maximum value at pH=13.5. Common approaches to nanoparticle dispersion are through physical methods (e.g., ultrasonic, high shear mixing, ball milling, etc.) and chemical methods (e.g., chemical modification of nanoparticle surfaces, use of dispersants such as surfactants, etc.). For the cementitious systems, a combination of ultrasonic and surfactant is mostly suggested. In this research, the effect of various surfactants on overcoming the agglomeration of halloysite nanotube in the cementitious environment was studied. The results indicated that the Polycarboxylate-based surfactant has better performance on improving the dispersion of HNT compared to that of other surfactants. Furthermore, incorporation of 3 wt% HNT enhanced the compressive, flexural and sorptivity of plain mortar up to 26, 22, and approximately 28%, respectively. The outcomes of the current paper display the fact that it is necessary to have special attention on the subject of the proper dispersion of nanomaterials in the cementitious environment for achieving the maximum efficiency of nanomaterials.