In this research, the production possibility of TiC-Al2O3 nanocomposite, as a useful ceramic from commercially pure TiO2, aluminum powder and carbon black has been investigated. Routile (TiO2) with carbon black and aluminum were placed in a high energy ball mill and sampled during different milling times. Then, the ACTIVATED powders were synthesized at different temperatures in an atmosphere control tube furnace. Our results show that using this method has decreased the synthesizing temperature to 1000-1250oC by increasing the milling time. Also the width of X-ray patterns peaks, had made it apparent that, the size of produced TiC crystals was in order of nanometer. Furthermore it was detected that the lattice parameter deviated slightly from the standard size.

IntroductionACTIVATED carbon has a wide range of applications as a porous material in the liquid or gas phase adsorption process. The physical process of ACTIVATED carbon production is divided into two stages thermal decomposition and activation. In this study, only the activation stage has been studied because it is very important in the properties of ACTIVATED carbon being produced.The production of ACTIVATED carbon from horticultural waste not only leads to cheap production and supply of many industrial and environmental necessities but also reduces the amount of the produced solid waste. Iran produces about 94,000 tons of pistachio husk annually, which is a good raw material for the production of ACTIVATED carbon. The profitability index of ACTIVATED carbon production in Iran is equal to 3.63, which in the case of export, the profitability index will be tripled.Studies have shown that temperature, period, and activation gas flow are the key factors affecting burn-off and iodine number during ACTIVATED carbon production. Among the various activators tested, steam was found to be the most efficient, with the fastest activation time. For pistachio crops, the minimum iodine number required for economic efficiency is 600 mg g-1, while the highest specific surface area according to the BET test is 1062.2 m2 g-1.Materials and MethodsA Mannesmann tube made of 10 mm thick steel was used to construct the rotating reactor. To minimize heat loss during operation, the kiln body was insulated with a ceramic blanket capable of withstanding temperatures up to 1400°C. The kiln had a length and diameter of 190 cm and 48 cm, respectively, and operated at a temperature of 600°C, requiring approximately 25 kWh of energy for heating. CATIA V5 R21 software was employed to design the device, while ANSYS R20 software was used for thermal and MECHANICAL analysis. The rotary reactor was identified as a critical component due to the high levels of thermal and MECHANICAL stress it experiences. To address these issues, a thermal and fluid analysis was conducted, followed by a MECHANICAL analysis using the results from the prior step. Subsequently, experimental tests were performed on the actual model, and the results were analyzed using statistical methods, including the T-student test in IBM SPSS software.The central heating unit and its surroundings were modeled using ANSYS CFX to obtain valuable information on fluid velocity, radiant properties, and heat transfer within the kiln and surrounding area at an operating temperature of 650°C. The analysis revealed uniform steam flow velocity between the kiln and the heating unit. To accommodate longitudinal expansion resulting from heat stress, taller rollers were employed to allow freedom of movement in that direction, while the lateral movement was unrestricted. This arrangement allows the reactor length to increase under varying temperatures. The reactor's end was designed with grooves and pressure plates, incorporating abrasion and compression plates made from refractory fibers to effectively seal the device. Furthermore, telescopic movement of the parts compensates for expansion effects.Results and DiscussionThe operating temperature of the system was gradually increased to reduce thermal stresses in the reactor shell. This led to a maximum increment in a longitudinal increase of 11.75 mm. Results from five sets of experimental tests and five software analyses demonstrated no significant differences between the experimental and analytical results at a significance level of 5%. Based on the thermal contour analysis, the thickness of the insulation layer was determined to be 5 cm. To control the operating temperature of the device, two methods were employed: adjusting the flame length of the burner and using different types of exhaust outlets. These measures effectively reduced thermal stress on the device.ConclusionThermal and MECHANICAL analysis were useful methods for predicting heat distribution, thermal stresses, and potential dimensional changes in the ACTIVATED carbon reactor. To compensate for possible alterations in the reactor's length and diameter, abrasive plates and friction washers were implemented. Careful control of fuel input to the burner and regulation of exhaust gas flow helped effectively reduce thermal stresses on the device.

Alkali-ACTIVATED concretes with slag base as new materials could be used to achieve a healthy environment without pollutants such as greenhouse gases and to solve the problems of water shortage and groundwater resources and use by-products produced during the processing of materials such as iron, steel and copper alloys for construction projects. On the other hand, porous concretes have economic and environmental potentials such as preventing flooding, increasing groundwater reserves, decreasing the flow of surface water. Slag-based alkaliACTIVATED concretes have been synthesized by natural pozzolans and industrial wastes such as sodium silicate with alkaline silicate and alkali hydroxide solutions. In the current study, the performance of alkali-ACTIVATED porous concrete with the different amounts of sodium hydroxide molarity and the ratio of sodium hydroxide to sodium silicate has been investigated in terms of MECHANICAL properties such as compressive strength. The flexibility and permeability of the specimens were also investigated. The tests have been performed on 9 series of samples with three values of 8, 12 and 16 Molar of sodium hydroxide and three ratios of sodium silicate to sodium hydroxide 1, 2 and 3 under curing times of 7, 14 and 28 days. The test results show that the alkali-ACTIVATED porous concrete indicated a higher initial strength compared to conventional porous concretes. The compressive strength at curing time of 14 days and flexural strength at curing time of 7 days were about 75% of its strength at curing time of 28 days which is significant. The compressive and flexural strengths have been increased with the increasing of molarity and the ratio of sodium silicate to sodium hydroxide about 20 to 25% and 9 to 13%, respectively. However, the permeability decreases with the increasing of molarity of sodium hydroxide solution or the ratio of sodium silicate to sodium hydroxide.

General thermo-MECHANICAL behavior of composites reinforced by shape memory alloy fibers is predicted using a three-dimensional analytical microMECHANICAL method to consider the effect of fibers activation. Composite due to the microMECHANICAL method can be exposed to general normal and shear MECHANICAL and thermal loading which cause to activate the shape memory alloy fibers within polymeric matrix finally. Considering the capabilities of the presented microMECHANICAL model; the fibers arrangement within the matrix is simulated as square distribution. Representative volume element of the composite system consists of two-phases including shape memory alloys fibers and polymeric matrix which is exposed to axial cyclic MECHANICAL loading. In order to display the effect of fiber activation on the overall response of composite, the behavior of polymeric matrix is assumed elastic and shape memory alloy fibers is considered nonlinear inelastic based on 3-D Lagoudas model is simulated. The model is capable to predict the phase transformation and super elastic behavior of shape memory alloys. In order to develop thermo-MECHANICAL equations of the shape memory alloy in the unit cell model, Newton-Raphson nonlinear numerical solution method is used. In the results, the effects of significant parameters on the thermo-MECHANICAL response of composites are investigated and then the composite thermo-MECHANICAL response is demonstrated in the high and low temperature interval and the effect of shape memory alloy wire activation in the composite is addressed. The presented results show that the composite residual strain in MECHANICAL unloading decreases by enhancing temperature. Therefore, the composite residual strain approaches to zero when the temperature is higher than at which austenite transformation finishes. Comparison between the present research results with available previous researches shows good agreement.

The development of novel concretes, such as self-compacting concrete, and employing new materials, including alkali ACTIVATED slag and fly ash, seem necessary for environmental protection and sustainable development in infrastructure. In this study, alkali ACTIVATED slag and fly ash are employed as an alternative eco-friendly binder to produce self-compacting concrete. MECHANICAL and thermal properties (using a semi-adiabatic calorimeter) of alkali ACTIVATED- and cementitious-self compacting concretes with three binder contents (500–600–700 kg/m³) were compared. All mixes had a water-to-binder ratio of 0.45. The alkaline solutions used consist of sodium hydroxide and sodium silicate solutions with 5, 6, and 7% Na ions and a constant activator modulus (ratio of SiO₂/Na₂O) of one. The finding demonstrated that the workability of fresh self-compacting concrete with different binder content satisfied the EFNARC limitation. Mixes with 700 kg/m³ binder content had the highest compressive and tensile strength and modulus of elasticity. Generally, the peak temperature and heat production of cementitious mixes were 14% and 56% more than those of alkali-ACTIVATED mixes, respectively.

In this research elements of the raw materials used to form MoSi2-TiC nanocomposite. The plan in this Research procedure was based on combustion synthesis, MECHANICAL activation mechanism (MASHS). Initially Mo, Si, Ti and C elemental powder were weighed by stoichiometry ratio and were milled with weight ratio of ball to powder 5 to 1, 10 to 1 & 15 to 1, milling time 4, 8, 12 hours with 250 and 300 rpm by the planetary mill. After wards the milled powders were compacted to pellet form by uniaxial press and synthesized samples were done in an atmospheric argon controlled tubular furnace with a temperature between 700 – 1100oC. To identify phases, XRD analysis was used and to evaluate morphology, SEM and TEM images were used. XRD patterns from synthesized samples with (MASHS) method show a successful composite molybdenum disilicide - titanium carbide synthesis. Results show the best process conditions for synthesis MoSi2-TiC nanocomposite with MASHS method was: milling duration about 4 hours, ball to powder weight ratio 15 to 1, mill rotation speed 300 rpm, constant pressure press 300MPa and temperature 850oC. The grain size calculation by reitveld method showed the size of titanium carbide crystallite and molybdenum disilicide in optimum condition of approximately 28 nm and above 100 nm respectively. The images of SEM and TEM proved that a nanostructure composite has been synthesized.

Unbleached chemi-MECHANICAL pulp of 85% pulp yield and produced from hornbeam, beech and populus woods respectively by 3: 1: 1 ratio, was used for peroxide bleaching. Two bleaching systems, alkali peroxide (conventional bleaching) and ACTIVATED peroxide by TAED activator, were used for pulp bleaching. Bleaching treatments included different percentages of hydrogen peroxide and caustic soda consumption. In this research, the hydrogen peroxide consumption rate, pulp yield, process selectivity, bleached pulp brightness and bleaching effluent pollution load (COD) were investigated. Results showed that, brightness values were increased by bleach chemicals charge rising, in both bleaching systems, but the increasing trend was downward. Also, pulp yield was decreased by increase of chemical charges, but residual peroxide was raised. The ACTIVATED peroxide process compare to conventional process had lower efficiency and brightness improvement values of pulp were less than those of alkali peroxide process. But pulp yield and effluent pollution load was less by ACTIVATED peroxide bleaching.

Geopolymers are alumino-silicate polymer that formed by alkali activation of Si and Al rich materials. This paper describes the effects of different alkaline solution types and concentrations, modulus of sodium silicate and sodium silicate to alkaline solution ratio on the flowability and MECHANICAL properties of alkali ACTIVATED slag and the optimum activator has been determined for the slag-based geopolymers production. Results reveal that adding the sodium silicate largely enhances the workability and compressive strength of slag-based geopolymer paste. The optimum modulus of sodium silicate and sodium silicate to alkaline solution ratio to reach the maximum strength are 2. 33 and 0. 4 respectively. At 91 days of curing, the compressive strength of the optimum mixture of slag-based gepolymer is about 74 % more than the compressive strength of ordinary Portland cement paste.