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In this research stabilization and clarification of pomegranate juice were studied. This juice was analyzed and its effective constitutes in this process were determined and important factors in after haze production were evaluated. Pectinas enzyme was used for pectin elimination and optimized consumption amount, temperature and time were obtained as 110PPM, 50C, 60min. respectively. Clarifying materials such as Gelatin (70 g/ton), Kieselsol 15 % (250ml/ton) and Bentonite (250g/ton) were used and in each case optimum condition and their advantages have studied. Our work has shown that carbon active is not acceptable for pomegranate juice clarification. The process has the best result in low temperature (20C). Also, for the first time PVPP (polyvinylpolypyrrolidone) was applied to solve secondary hazes problems and to produce stable clarified juice whose satisfying results have reported. Its consumption amount was determined as 80 g/100 lit. .

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The use of enzymes in organic solvents has biotechnological and industrial importance. Organic solvents can decrease the stability of enzymes that is a challenge for the use of enzymes in organic media. There are several approaches such as protein engineering, chemical modification, and use of additives for stabilization of enzymes in organic solvents. In this study, activity and stability of trypsin were investigated in the presence of different organic solvents. Then the effect of sucrose on the stability of the enzyme was investigated in the absence and prescence of solvents. The result showed that the activity and stability of trypsin were decreased in the presence of organic solvents. DMF had a lowest effect on the activity and stability of the enzyme. The use of sucrose increased the stability of trypsin in the presence of organic solvents. The stabilization effect of sucrose in the presence of DMF was more than other solvents. Consequently, a mixture of DMF and sucrose is proposed for the use of trypsin in industrial applications.

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Cellulase enzyme has shown their potential application in different industry. cellulase immobilization is one of the different methods for enzymatic stabilization. An advantage of immobilization is enzymatic reusability, which have an economical advantage for enzyme using in industry. Properties of Chitosan as a support for enzyme immobilization are always considerable. Due to its unique biological properties such as biocompability, biodegradability and non-toxicity, chitosan is an attractive support for immobilization. In this investigation Aa-cel9A endoglucanase gene was cloned in pET28 (+) expression vector. Sequencing result had been proved gene cloning in vector. Then the constructed vector was transformed to Eshershia.Coli (BL21) cells and enzyme production was induced. The result obtained from SDS-PAGE analysis and enzymatic assay showed the recombinant protein has been expressed and protein purification was done with Ni-NTA column. Chitosan macrobeads were prepared by precipitation procedure. After immobilization of enzyme with glutaraldehyde as linker, enzyme immobilization has been proved with FTIR and Bradford analysis. The obtained result showed optimum condition for covalent immobization on support are 0.7% of glutaraldehyde concentration and sodium phosphate buffer with pH 7. Bradford analysis and enzymatic activity assay have proved 85% of enzyme molecules immobilized on support.

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Uricase or urate oxidase is an enzyme that converts uric acid (with low solubility) to 5-hydroxyisourate and finally to allantoin. The possibility of developing some diseases like gout and kidney stones will be increased in high levels of uric acid. Thus, uricase can be used as drug enzyme to reduce uric acid levels in the blood. The low stability of proteins (such as drug enzymes) is a challenge in the use of them. There are several approaches such as use of additives for protein stabilization. In this study, E. Coli BL21 (DE3) was transformed by pET28a (+) vector carrying Aspergillus flavus uricase gene. The recombinant protein was expressed and then purified by a Ni-NTA agarose chromatography column. After purification, the thermal stability of the purified enzyme was evaluated and then it stabilized by additives. The results showed that enzyme is active and purified very well. Thermal stability results indicated that uricase maintains its stability up to 20°C and then loses its stability. The half-life of enzyme was 30minutes at 40 °. The results of enzyme stabilization by 20% (v/w) concentration of glucose and sorbitol as well as by 20 % (v/v) of glycerol showed that glucose had the most stabilization effect on the uricase among the additives. The stability (half life) of enzyme was increased more than two times in the presence of glucose. Finally, we conclude that additives like glucose which increase surface tension have the most stabilization effect on the uricase enzyme stability.

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Inertial stabilization of a sensor mounted on non-stationary platforms is an important task in many applications such as image processing, astronomical telescopes, and tracking systems. For this purpose, some type of gimbaling arrangements is typically used. For implementing the LOS stabilization, usually a two-axes gimbal system is used which the sensor is mounted in the inner gimbal. The dynamic modeling and designing the control system for two axes gimbal system have been studied extensively, but there is a few works on three axes gimbal system. In this paper, the equation of motion for a three axes gimbal system is derived by the moment equation. The effect of angular velocities of the base into the gimbaled dynamic system and cross-coupling between gimbals are presented. In addition, some critical notes are presented for constructing the gimbal assembly. Moreover, a model based control strategy is proposed for controlling the gimbal dynamics.   .  

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Stability analysis of earth slopes is among the major issues raised in geotechnical engineering which has involved so many researchers in different parts of the world. When stability of an earth slope is suspected, it is necessary to take preventive measures before instability happens. The first step to maintain the stability of an earth slope is performing excavation in the slope crest or/and filling in the slope toe. This is the cheapest way (model) for stabilization of earth slopes. If the model cannot provide the required factor of safety, it is necessary to use other stabilization methods. Numerical and laboratory methods are useful for modeling earth slopes stabilization. Modeling the stability of earth slopes using numerical methods is a common practice in geotechnical engineering. Moreover, stabilization of earth slopes using piles has been practiced by many researchers by using numerical and analytical methods. Although numerical and analytical methods have special capabilities, laboratory modeling is more reliable. Hence, it is discussed in this article. Stabilization of earth slopes with reinforced concrete piles is one of the important concerns of geotechnical engineering. Application of numerical and analytical methods to stabilization of earth slopes using piles is an issue commonly discussed by various researchers. Optimal location of concrete pile for stabilization of earth slope by means of numerical and analytical methods, has been practiced by various researchers. Their efforts have led to various results raising the question of what the optimal place for installation of a pile is. It seems that no experimental studies are conducted in this regard, which is discussed in this article. Experimental studies conducted in this article have the potential to solve the problem caused by varying and sometimes contradictory results of numerical analyses performed to find the optimal pile location. In this article, an experimental analysis of a homogeneous sand earth slope is conducted. The slope is saturated through precipitation and failure after loading by installing the reinforced concrete pile in different locations. All of the experimental tests were modeled and compared using the limit equilibrium (LE) and finite element (FE) methods, which are compliant with each other. The results obtained by experimental tests show the optimal location for installing reinforced concrete pile in a homogeneous sand slope for achieving the highest factor of safety and reduce costs of stabilization. In the present article, the optimal pile location for slope stabilization is determined by conducting laboratory studies of a layer sand slope saturated through precipitation. The resultant failure mechanism leads to acceptable results that help choose the optimal location for pile installation. The slope is stabilized by repeating the test and installing the pile in the optimal location, which is the best place to install the pile. The FE method (Plaxis software) and LE method were used to confirm the laboratory tests as well.

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Sand and gravel materials are commonly use for structure layers of roads. These materials are providing from riverbeds and mines, which are usually far from the operation site area. While the process involves manipulation of riverbeds and mines it also has a significant cost, most of it in extraction, transportation, Gradation correction, fuel and machinery.Researches done in different countries are showing that in cases soil is in good quality, stabilized mixture of soil can be used instead of sand and gravel. These can reults a signifactnt amount of money saving by providing soil from near the road and eliminating the process of Gradation correction. However, there are resistance and inflammatory parameters of fine soils, which play an important, usually problematic, role in structure buildings. The abundance of fine-grained clayey soils in the country, have created serious problems in construction projects. One of the ways to modify or improve the properties of these soils is stabilizing. Lime as a stabilizer for fine-grained soils is famous. In this thesis, the effect of four chemical additives on the CBR strength of soil stabilized with lime is studied. In addition, effect of additives on properties such as swelling, water absorption and density of soil stabilized with lime is studied. These additives with names "Panplast R", "RB - PC 386", "RB - PC 375" and "Planicrete SP" as a lubricant and concrete superplasticizer have the desired effect on the chemical and physical properties of concrete. Moreover, the Cementation act of stabilized soil with lime is like cement. In this study, the effects of those additives on lime-stabilized soil are studied. First four different combinations of soil and different percentages of lime made. The results obtained optimized percentage of lime. Then optimized percentage of lime and different percentages of additives used to build the different samples. In order to avoid faults and testing errors, each combination made by two samples. All desired results were presente as mean values obtained from two samples. Total of 49 samples were built and tested. Due to determine the effect of curing time of each combination, two sample with 7-day curing time and two other with 14-day curing time are made. In order to preserve the moisture in the samples during the curing time they were stored in sealed thick nylon bags. After curing time for each sample for 96 hours at constant temperature water baths were maintaine to monitor inflation and the water absorption. After time the CBR test done. Finally, the Additives "Panplast-R" and "RB-PC 375" had a favorable impact on listed properties, so that the CBR result was 90% and 99%, the "RB-PC 386" was almost effectless, and the "Planicrete-SP" has shown Negative impact on the properties of interest. so that the CBR result was 65%.

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Expansive clayey soils, which are predominantly distributed throughout the world, have complicated behavior. Heaving and settling in these soils may pose considerable problems and severe damage to structures that come into their contact or constructed out of them and consequent distress to people if not adequately taken care of. Granulated blast furnace slag (GBFS) and basic oxygen furnace slag (BOS) are two types of by-product materials resulting from the manufacture of iron that are produced in large amount throughout the world. The proper disposal of such byproducts is one of the major issues for environmentalists since leaving them to the environment directly may cause health problems. Hence, the aim of this study is to investigate the potential use and effectiveness of expansive soils treatment using GBFS and BOS. To achieve the objectives, the admixtures were added to the clay smectite samples in proportion of 0 to 30% by weight and tests of the pH value, electrical conductivity (EC) measurement, Atterberg limits, swelling, unconfined compression strength (UCS) and X-ray diffraction analysis were performed on those samples at different curing period (i.e. 1, 3, 7, 14, 28, 45 and 90 days). Lime as a conventional additive was also used to evaluate the performance of GBFS and BOS. The results reveal that in the limited curing condition (i.e. less than 3 days) and with the addition of 20% slag, the swelling could be eliminated mainly due to the short term reactions (i.e. cation exchange and osmotic pressure increasing). On the other hand, based on the X-ray graphs it was found that with appropriate curing (more than 7 days) and due to the growth of the cementation compounds such as calcium silicate hydrates (CSH) and calcium aluminate hydrates (CAH), especially in samples containing BOS, the needed slag to control heave potential will be declined up to 4 times. The presented results indicate that highly expansive clayey soils can be stabilized satisfactorily by lime and following adequate curing due to development of the pozzolanic reaction. Beside, with a further increase in the lime content, the pozzolanic activity can not continuously take place and the excessive addition of lime caused a reduction in the mechanical capacity. On the other hand, the samples containing slag show a progressive increase in the strength with increasing the additive content and could overcome the difficulties associated with the use of lime. For example, the USC of smectite sample with 30% BOS and after 90 days of curing was almost 12 times higher than the untreated sample. However, in the presences of GBFS due to lower solubility and limitation of pozolanic activity the lower change was observed. The The macro and micro level experiments results of this study indicate that the utilization of iron and steel slags especially basic oxygen furnace slag (BOF) is a good alternative for lime stabilization which reduces the cost of soil treatment project and help the management of these byproducts.

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This paper investigates the robust finite time stability and finite time stabilization for a class of uncertain switched systems which have time delay. The emphasis of the paper is on the cases where uncertainties are time varying and unknown but norm bounded. By using the average dwell time approach and multiple Lyapunov like functions, delay dependent sufficient conditions for finite time stability of uncertain switched systems with time delay in terms of a set of the linear matrix inequalities are presented. Then, the corresponding conditions are obtained for finite time stabilization of uncertain switched time delay systems via a state feedback controller. The controller is designed by virtue of the linear matrix inequalities and the cone complement linearization method. We solved the problem of uncertainty in uncertain switched time delay systems by resorting to Yakubovich lemma. Finally, numerical examples are provided to verify the effectiveness of the proposed theorem.
 

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In this paper, a method of tri-axial gravity gradient stabilization of satellite in circular orbit is proposed and investigated. In this method, only one actuator is employed. A satellite with varying-length boom is considered consisting of two rigid bodies having the freedom of moving in the boom direction. The only control input is the force between these two bodies to control the varying-length boom. The gravity gradient torque is considered as the only external torque acting on the satellite. The system is under-actuated and has Hamiltonian structure. So, the port-Hamiltonian approach is utilized. The equations of motion of the system are obtained in Hamiltonian formulation. The equilibrium points and their required control inputs are determined. The linearization around the equilibria is carried out and it can be seen that the linear dynamics of pitch-boom and roll-yaw are decoupled. Therefore, the roll-yaw dynamics is linearly uncontrollable. The method of energy shaping and damping injection is used for controller design. The conditions on the energy shaping control law to stabilize the system are determined. Further, the resulting closed-loop system is analyzed. The closed-loop system has center manifolds. Finally, the performance of the closed-loop system, convergence of state trajectory to the center manifold and its non-exponential convergence is shown by simulation.

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What should be considered at the beginning of any stabilization process besides slope safety is the minimization of expenses. Therefore, excavation on slope upstream and/or filling slope downstream and/or moderating slope angle are the primary and effective stabilization methods. If these methods cannot provide the desirable factor of safety it would be necessary to put effort in other methods such as increasing soil strength parameters, draining surface water and sub-surface (ground) water at embankments, and installing retaining walls and piles. Implementation of these solutions is usually costly and sometimes in order to achieve a desirable factor of safety it is necessary to combine one or several methods. Anyway, the aforementioned solutions are aimed at mitigating the driving force behind ruptures and/or increasing resistive forces. Slopes stabilization methods can be studied as empirical, analytical, and numerical methods. This classification has been so far used by researchers and has undergone numerous studies. One of the methods used for improving resistive forces is the installation of piles in earth slopes. Installing piles for stabilizing susceptible earth slope is an effective way of preventing the imbalance of force and instability. Stabilizing effect by using pile is provided by the passive resistance of the pile below the slip surface and load transfer from the sliding mass to the underlying stationary soil or rock formation through the piles due to soil arching mechanism. Moreover, slope stability and optimizing pile location by installing a row of piles have been studied by many researchers. The piles are embedded in the stable soil by the length 5D (D=pile diameter), because the zone of influence of each pile has been demonstrated not to exceed 5D and the length of the pile is restricted to 10D. In this paper a new method is presented for estimating of displacement and lateral force acting on stabilizing piles in earth slopes. The growth mechanism of lateral force acting on stabilizing piles in a row due to the surrounding ground undergoing plastic deformation is discussed, and its theoretical analysis is carried out considering the interval between the piles (Ito and Matsui, 1975). Several methods have been proposed to determine the force exerted on the pile in addition to having the merits, defects such as lack of accuracy required in a particular interval between the piles. In this paper with regarded to initial slip surface and acting force due to weight of failed soil is proposed lateral force acting on piles. 1. The assumptions are considered in this paper are, 2. The suitable location for installing of piles is middle of slope. 3. The pile behavior is considered as elastic. 4. The soil behavior is considered as elastoplastic. 5. The pile tip is embedded in the stable soil by the length 5D.

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The lack of accessibility of high quality materials and the increased costs associated with the use of these materials will finally demand engineers to use local soils. In such cases, ground improvement performed reasonably in many conditions. Ground improvement can be defined as the procedure of increasing shear strength parameters and decreasing the permeability and compressibility of the soil. Different methods can be used to improve the geotechnical properties of the problematic soils such as loose sand that one of them is using additives. The stabilization of soils with cement is an attractive technique due to economic and environmental issues and avoiding the use of borrow materials from elsewhere. Cementation of sand results in increased brittle behavior as peak compression strength increases. The compressive strength of artificially cemented soils has been studied in the past by several investigators.A number of studies have also reported on the influence fiber, glass, fly ash, silica fume and nono particle on the mechanical behavior of cemented sands .However, to the author’s knowledge, there has been a little effort devoted to the research on the use of pozzolans such as natural zeolite as an addictive material to the cemented sands. Natural zeolite, an extender, has been investigated for use as cement and concrete improver by some researchers.
It is widely known and well emphasized that the cemented sand is one of economic and environmental topics in soil stabilization. In some instances, a blend of sand, cement and other materials such as fiber, glass, nano particle and zeolite can commercially available and effectively used in soil stabilization in road construction. In this investigation, zeolite and its effect on unconfined compression studied as one of addictive material to cement. Therefore, cilinopiolite kind of zeolite, Neka cement type II and Babolsar sand are used. A total number of 144 unconfined compression tests were carried out on 24 combination type of cement and zeolite include different cement percentages 2, 4, 6 and 8 percent of total dry weight of samples and replacement percent’s of 0, 10, 30, 50, 70 and 90 zeolite with cement based on 50,70 and 85% relative densities in7 and 28 days curing times. Results show that in 28 day curing time, by replacement percentage of 30 zeolite material by cement, the unconfined strength increased 20 to80% in comparison with cemented samples by increasing shear strain. For higher cement content and less compacted blends, these improvement rates are more. At the end, a power function fits presented to relate unconfined compressive strength (UCS) and zeolite-cement-soil parameters (porosity (n) and voids/ polynomial model of cement and zeolite voids).It is widely known and well emphasized that the cemented sand is one of economic and environmental topics in soil stabilization. In some instances, a blend of sand, cement and other materials such as fiber, glass, nano particle and zeolite can commercially available and effectively used in soil stabilization in road construction. In this investigation, zeolite and its effect on unconfined compression studied as one of addictive material to cement. Therefore, cilinopiolite kind of zeolite, Neka cement type II and Babolsar sand are used. A total number of 144 unconfined compression tests were carried out on 24 combination type of cement and zeolite include different cement percentages 2, 4, 6 and 8 percent of total dry weight of samples and replacement percent’s of 0, 10, 30, 50, 70 and 90 zeolite with cement based on 50,70 and 85% relative densities in7 and 28 days curing times. Results show that in 28 day curing time, by replacement percentage of 30 zeolite material by cement, the unconfined strength increased 20 to80% in comparison with cemented samples by increasing shear strain. For higher cement content and less compacted blends, these improvement rates are more. At the end, a power function fits presented to relate unconfined compressive strength (UCS) and zeolite-cement-soil parameters (porosity (n) and voids/ polynomial model of cement and zeolite voids).

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The use of synthetic antioxidants has reduced due to its harmful effects on consumer health. The present study was conducted to evaluate the antioxidant properties of Mentha pulegium as a source of natural antioxidants. In order to prepare extracts of Mentha pulegium from a methanol solution, a ratio of 5: 1 was used. The levels of tocopherol and phenolic compounds of the extracts were measured by spectrophotometric methods. Finally, methanolic extract of Mentha pulegium at concentrations of 400 ppm and 800 ppm was added to canola oil, and after heating for 24 hours at 180°C, color index, conjugated dienes value, acid value and peroxide value were evaluated to comparison with the sample containing TBHQ. The results showed that extract at concentration of 800ppm has thermal stabilization efficiency comparable to TBHQ(p<0.05). Therefore, Mentha extracts can be recommended as a potent source of natural antioxidants for the stabilization of canola oil or other unsaturated vegetable oils.
 

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Circular micro-plates are used in microelectromechanical systems (MEMS) such as micro-pumps and ultrasonic transducers due to their special geometry. One of the most important problems with electrostatic micro-actuators is pull-in instability which prevents large displacements. Stabilization in beyond pull-in displacements can be attained using an appropriate controller. This paper presents a position control problem for an electrostatic micro-actuator consisting two circular clamped micro-plates to enhance the stroke and speed up the input commands. To consider the modeling error and geometric uncertainties, a fuzzy controller is applied. First, the equation of the plates vibration is derived using Lagrange equation with single mode assumption. Fuzzy rule-base is constructed according to static and dynamic simulations. Genetic algorithm is utilized for finding the optimum parameters of the controller to accelerate accomplishing the commands. Finally, the maximum voltage of the plates is fitted with a function using the optimization results for full range gap commands. The performance of the fuzzy controller along with this function is depicted applying step, multiple step and chirp commands. The obtained results show that the objective has been met well.

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The increasing demand for engineered cut and fill slopes on construction goals has increased the need of understanding of analytical methods, investigation tools and the most important stabilization methods to solve slope stability problems. The first step to maintain the stability of an earth slope is performing excavation in the slope crest or/and filling in the slope toe. This is the cheapest way (model) for stabilization of earth slopes. If the model cannot provide the required factor of safety, it is necessary to use other stabilization methods. Numerical and laboratory methods are useful for modeling earth slopes stabilization. Modeling the stability of earth slopes using numerical methods is a common practice in geotechnical engineering. Moreover , stabilization of earth slopes using piles has been practiced by many researchers by using numerical and analytical methods. Application of numerical and analytical methods to stabilization of earth slopes using piles is an issue commonly discussed by various researchers. Although , numerical and analytical methods have special capabilities, laboratory modeling is more reliable. Stability slope analysis has attract lots of researchers attention all across the world and it shows the significance of this matter. When we are suspicious about stability of earth slopes, immediate actions and preventative steps should be used for suppression of instability occurrence. Many projects intersect in valleys and rides , which can be prone to slope stability problems. Natural slopes that have been stable for many years may suddenly fail because of many reasons, therefore finding useful techniques for these matters now days are a great concern for geotechnical engineers. In all earth slopes the primary way for stabilization is the excavation in slope crest and/or filling slope toes , if this action would not increase safety factor enough , other procedures should be applied. Three common styles of stabilization methods are ; vertical reinforcement (such as stone columns and piles) , horizontal reinforcement (like Geo - grids) , oblique reinforcement (such as nailing). Stability of natural slopes is one of important issues in Geotechnical engineering. using easy and economical methods for improving stability of slopes are one of the greatest challenges that face engineers. One of the common methods that is use for increasing the safety factor of slopes is stone columns. All of the experimental tests were modeled and compared using the limit equilibrium (LE) and finite element (FE) methods, which are compliant with each other. Understanding of soil property is crucial for analysis of earth slopes, in this study effect of cohesion in embankment is considered, and based on exact understanding of this property and performing laboratory modeling and by using finite element method software (PLAXIS2D) and finite difference method software (FLAC3D), results are achieved. The sand slope is saturated through precipitation and failure after loading by installing the stone column at the middle of slope. Experimental studies in this article have the potential to give valuable information about effects of embankment cohesion and penetration depth of stone column into the stiffer layer, in stability of stone column reinforced earth slopes.

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Clayey soils usually have low bearing capacity, high compressibility, shrinkage and swell characteristics. Several methods have been adopted to improve the geotechnical properties of such soils. Soil stabilizing by chemical materials is one of the most common methods for treating fine grained soils. Lime has been used to improve some mechanical and plastic properties of fine grained soils since many years ego. In recent years some studies has been also carried out to investigate the influence of adding pozzolany materials on the geotechnical properties of lime – treated clayey soils. Geotechnical behavior of clayey soils depends on chemistry of pore fluid. When drinking water is used to provide the needed moisture of soil in the laboratory, it will be lead to incorrect interpretation in engineering properties of soil where specific water such as sea water is utilized. Therefore, if the undrinkable water has been used to provide soil moisture, it is necessary to examine the behavior characteristics of the materials by the same water. For example, presence of some sulphates in the soil stabilized with lime leads to problems such as reduction of strength and increase of swelling in clay. In this laboratory study, effect of sea water on strength of stabilized kaolinite has been investigated by conducting several unconfined compression tests. The specimens were prepared at fore percentage of lime and pozzolan (i.e.0%,1%,3%,5%) by weight of dry soil and distilled water and three saline water which were taken from Caspian Sea, Persian Gulf and Urmia Lake. for every combination ,weight of each material was determined exactly based on the optimum moisture content and maximum dry density which is obtained from the standard proctor compaction test. Clay and lime and pozzolan were mixed in dry condition properly and then water was added gradually. Afterwards, the mixtures were kept in plastic bags for 24 hours. Weight of each specimen was determined in accordance with given specific volume and obtained maximum dry density from compaction test. This weight was divided into four portion and each portion was compacted in 20 mm layer in a PVC mold . The specimens were cured in a oven having a temperature about 35 ֠ C for 3, 7 and 14 days. After each curing time a extruder was used to remove the specimens from the molds with constant rate vertically to avoid bending and formation of tensile cracks. Then the specimens were immediately tested under strain controlled at constant loading rate of 1.0 mm per minute , according to requirements of ASTM D 2166. For each combination , three specimens were examined to assure repeatability of results. The results of conducted experiments indicate that unconfined strength of samples without additives (lime and pozzolan) prepared by sea water are higher than specimens containing distilled water. For the samples containing Urmia lake water, the unconfined strength were higher than the other samples. Also, for the specimens in which additive has been used, the strength of the samples containing Caspian Sea and Persian Gulf water were more than that with distilled water and the strength of samples containing Urmia lake water was less because of differences in the concentration of salts existed in the water . Finally, the results show that water minerals are higher in Urmia lake water, Persian Gulf and Caspian Sea, respectively.

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One of the main topics in the field of robotics is the motion control of wheeled mobile robots. Motion control encompasses trajectory tracking and point stabilization problems. In this paper these control problems will be considered for the tractor-trailer wheeled robots and a predictive control algorithm is developed for solving these problems. Therefore first kinematic model of the tractor_trailer robot is developed. Next, reference trajectories is produced for the system. Subsequently, predictive control law is designed for the trajectory tracking and point stabilization problems. Predictive control based on the known values of reference trajectories in the future, produces the control inputs in present time. Consequently the error signal with respect to the reference trajectory in future will be used in order to control the system at the present instant of time. This method is developed for solving the aforementioned control problems and is employed on the tractor_trailer wheeled robot. As can be seen from the results, the proposed control algorithm steer the wheeled robot asymptotically follow reference trajectories. Obtained results from the implementation of the proposed method for solving trajectory tracking and point stabilization problems, demonstrate the effectiveness of the presented algorithm.

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In this study, stabilization attitude control of a rigid satellite with on-off thrusters using pulse-width pulse-frequency (PWPF) modulator is investigated in presence of sensor noise. The preferred regions of the PWPF modulator parameters and stabilization control gain are obtained based on the two performance indices of the fuel consumption and the total number of thruster firings. The analyses include tumbling, detumbling, and stabilization block as an internal loop of the satellite pointing mode. The design parameters are reduced by using the quasi-normalized equations of PWPF modulator. Therefore, the preferred regions are extracted based on search method in terms of grouped parameters, regardless of the value of each parameter, separately. In quasi-normalized form, the computational burden is considerably decreased, especially in the statistical analysis in the presence of sensor noise. The parametric study is carried out with/without sensor noise. The parameters are also tuned using multi-objective optimization with genetic algorithm for stabilization mode without sensor noise. In the presence of sensor noise, the behaviors of the parameters are plotted versus the noise power spectral density. In order to better specify the preferred regions, each quasi-normalized design curve is plotted for a specified value of the input noise power spectral density. The parameters of the satellite attitude control system are suggested to be tuned/optimized within the preferred regions of the parameters in the stabilization loop as an internal loop.

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Abstract: Introduction: Solidification and stabilization of heavy metal contaminants is recognized as the technology to prevent transfer of contaminants to the lower layers of soil and groundwater. A noticeable increase in distribution of heavy metal contaminants in recent years highlights the importance of effective methods for engineering disposal of industrial wastes. The most important challenge ahead of this endeavor is perhaps the determination of right framework and mechanism of action. Precise mechanism of mobility of contaminants can be grasped by gaining accurate and comprehensive understanding about system behavior and evaluating it from the nano- and micro-structure perspectives. Nano- and micro-sized clay particles can be used effectively as adsorbents of many contaminants (e.g. heavy metal ions and organic compounds) in sewage and wastewater. Moreover, as clay soils have high cation exchange capacity (CEC), they provide appropriate conditions for cation exchange and create considerable capacity to retain heavy metal contaminants. In spite of conducting extensive studies on stabilizing contaminants by the use of cement, inadequate attentions have been paid to microstructure study of interaction process of clay particles, heavy metal ions, and cement, specifically in cement hydration process in different time intervals. Based on this, the present research aims to study the interaction process of clay particles, heavy metal contaminants, and cement over time from the perspective of microstructure. This include the investigation of the effect of presence of heavy metal on cement hydration process and formation of nano-structure calcium silicate hydrate (C-S-H). Material and method: In this study, the behavioral tests were conducted on natural clay soil collected from the Qazvin Plain, Iran. The purpose of this selection was to determine geotechnical-environmental properties and contaminant adsorption-retention capability of samples of natural clay with average specific surface area and CEC and the effects of natural clay on the solidification and stabilization process. The majority of experiments of this study were conducted based on ASTM standards and geotechnical-environmental test guidelines of McGill University (Canada). Density and pH of clay samples were determined in accordance with ASTM, D854 and ASTM, D4972 standards. Soil carbon content was determined by titration. Specific surface area (SSA) of the soil was measured using EGME solution. The cation exchange capacity (CEC) of the soil was determined using 0.1 M barium chloride solution. Meanwhile, different concentrations of heavy metal contaminant (zinc) and different percentages of Portland cement were added to natural clay. The interaction process was analyzed experimentally by examining pH changes and evaluating microstructure study (XRD). Result and discussion: According to laboratory results obtained in this study, the high specific surface area of C-S-H nanostructure improves the adsorption characteristics and leads to better filling of pores. It also improves the retention capability by decreasing the mobility of heavy metal contaminants via encapsulation of their ions (solidification). The results show that formation of C-S-H nanostructure improves absorption features due to high specific surface area and decreases mobility of the heavy metal ions through their encapsulation (solidification). In addition, the presence of the heavy mental contaminant (zinc) reduces formation of C-S-H nanostructure so that the presence of 25 cmol/kg-soil of heavy metal ion (zinc) decreases peak intensity of C-S-H nanostructure about 160 CpS.