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In order to develop the scope of application of polymer materials in the preparation of drilling fluids, in this study, various blends of wheat starch and copolymer of sulfonated polyacrylamide were prepared and the rheology and compatibility behavior of samples under different salinity and aging conditions were evaluated. The rheological behavior of starch-polyacrylamide blends in tap water and saturated brine water showed that the viscosity of the samples increased with increasing concentration of polyacrylamide copolymer in the both media. However, starch-polyacrylamide blends in saturated brine had less viscosity than tap water. It was observed that in both tap water and salt water saturated conditions after 4 hours of aging at 90 ° C, the viscosity of most samples increased. Comparison of the curves for empirical viscosity data and prediction of the mixing rule showed that in both of tap water and salt saturated water, positive deviation from the mixing rule is observed, which indicates the compatibility between the blend components. By performing the aging process, although positive deviation was still observed, this positive deviation slightly decreased, which means the negative effect of aging on the compatibility of the starch- copolymer of sulfonated polyacrylamide blend.
In conclusion, the results of this study showed that the blend of starch- sulfonated polyacrylamide copolymer is compatible at high temperature (90 °C) and saturated NaCl salt wate. Moreover, in some samples, this compatibility exists even after aging.
 

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Analysis of signed biological networks has been an interest of some researchers in recent years. We consider communities and balanced clusters as two structural patterns that may reveal different structures in the networks. Although biological networks tend to structural balance, this study clarifies adhesive communities in some transcriptional networks of ecoli and yeast differ from the balanced clusters and have significantly more negative links in their structure. This difference may be used as an index in categorizing various systems' structure and function. Also we study the important role of the positive links between balanced clusters, even though the links between these clusters are mostly negative. Analyzing data of some Gene Regulatory Networks, shows that perturbing the genes located at these links, has a larger effect on the system and causes more distance from the initial equilibrium state. So, signed clustering and detecting the links between these clusters can be considered as an effective approach in detecting the functional units and the key components in the system. This can be useful in applications like gene targeting in drug synthesis.

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The main problem in strategic planning debate is not the formulation, but its implementation and execution. The main purpose of this research is to design a model for implementation and successful execution of strategies in hierarchical organizations. In term of goal this research is applied because it seeks for a framework to help implement and successfully implement a strategic plan. The method of collecting information from this research was library studies and conducted a deep interview with experts in field of the study. The methodology of this research is multi-grounded, so that after the stage of library studies, the variables related to implementation and execution of the strategy found in literature, identified by content analysis and grouped in two groups of individual and organizational factors. Based on these factors, an initial model provided. Then, using results of in-depth interviews with 30 experts (snowball method was used for sampling) familiar with the strategic management and planning, a model based on the factors based on interviewees have been developed. In this model also the factors are grouped in two levels: individual and organizational. The final model developed based on the combination of theoretical literature model and the model derived from the interviews and is presented in the form of a model consisting of the successful implementation and execution of strategy, as well as the results of its implementation and execution at the individual and organizational levels.

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Abstract: The influence of cement content increase on corrosion resistant behavior in concretes containing nano-SiO2 was experimentally studied. For comparison, the chloride diffusion of plain concrete and the concrete containing nano-SiO2 was also experimentally studied. The test results indicated that the corrosion resistance of concretes containing nano-particles is significantly improved. However, the index of diffusion chloride ion in the concretes containing nano-SiO2 is directly related to cement content in the mix. The SEM oservations revealed that the microstructure of concrete with nano-SiO2 is more uniform and compact than that of normal concrete, but higher pore size distribution was observed when cement content is increased, which in turn leads to the increase in the diffusion of choloride ion.

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This paper develops new results on the use of model predictive control to regulate the attitude of a ground station antenna. Two degree of freedom AZ-EL pedestal is considered as ground station antenna. Permanent Magnet Synchronous Motors are taken into consideration as the best choice for satisfaction of control objectives as actuators. The design is based on a two cascade controller consist of MPC and a simple feedback linearization, respectively. The proposed approach provides more smooth tracking and lower energy consumption with respect to analogous works. The model predictive controller employs integral action, resulting in zero steady-state error and load torque disturbance rejection. Realistic disturbances caused by wind and load is considered and applied to an industry-sized pedestal. The reference data of azimuth and elevation angles are chosen from a real tracking mission. The comparison of simulation results by typical PI controller, verify the effectiveness of the proposed method.

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Transforming growth factor beta (TGF-β), is a small homodimeric signaling protein. The TGF-β isoforms (TGFβ1, β2 and β3) are involved in many cellular processes including growth inhibition, extracellular matrix remodeling, tissue development, cell migration, invasion and immune regulation. For research aims, TGFβs are overexpressed using recombinant eukaryotic cell or bacterial expression systems. For achieving an efficient purification of TGF-β by immobilized metal ion affinity chromatography (IMAC), a histidine tag was placed either at the C-terminal (C-TGFβ) or N-terminal (N-TGFβ) region of the sequence and the effect of His-tag on TGF-β structure has been studied by computational tools. Proteins 3D structures were modeled using MODELLER software and molecular dynamics simulation of native TGF-β and modelled proteins, N-TGFβ and C-TGFβ were studied in water by GROMACS package. Protein dynamics modeling indicated that the His-tag attached at the C-terminus but not at the N-terminus of the TGF-β can affect the fluctuations of amino acids and protein structure. It is concluded that the C-terminal tagging may cause distortion and misfolding in the structure.

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Objective: Escherichia coli is the most prevalent etiologic agent of urinary tract infections which is the cause of about 80% of cases. Enzymatic inactivation of aminoglycosides by aminoglycoside-modifying enzymes is the main mechanism of resistance to these antibiotics in Escherichia coli. The aim of this study was the detection of aac(3)-IIa gene among aminoglycoside resistant clinical isolates of E. coli using PCR method. Materials and Methods: After collection of 250 clinical isolates of E. coli, antibiotic susceptibility patterns of isolates were determined by disk diffusion method for gentamicin, amikacin, tobramycin, kanamycin and netilmicin by considering the CLSI principles. Chromosomal and plasmid DNA of the isolates were extracted using DNA extraction Kits and PCR method was used for detection of the aac(3)-IIa gene. Results: Results show that 96% of E. coli isolates were resistant to tobramycin, 90% resistant to kanamycin, 82% resistant to gentamicin, 30% resistant to netilmicin and 8% resistant to amikacin. aac(3)-IIa gene was detected in 54.83% of E. coli isolates. Conclusion: Because of high prevalence of resistance toward aminoglycoside antibiotics which is due to its transfer among bacteria by transferable elements such as transposons and plasmids. Therefor, tracing transfer routs among different bacteria is very important.

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Orthopedic plates are currently used in bone healing process. However they cause density loss because of the change in natural stress patterns.The aim of this study was to evaluate a newly developed bone plate using functional graded material in term of stress pattern. In the present study, 3D finite element models of tibial bone plate with variable stiffness of a graded material and traditional bone plates made of stainless steel and Ti alloy have been developed by using the ABAQUS software. Effects on the predicted stresses at the fracture site in the presence of a distance between the plate and fractured bone were also studied. For this purpose, a 3D model of tibia was created with the exact geometry of the real bone geometry by using CT scan images of a human left leg. Results showed that the bone plate with graded material offers less stress-shielding to the bone, providing a higher compressive stress at bone to induce accelerated healing in comparison with Ti alloy and stainless-steel bone plate. Results also showed that the use of non-contact plates provide a favorable mechanical environment for the following fracture healing.

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Customer churn management consist of three main phases: identifying churners, discovering the causes of churn and adapting appropriate strategies against this problem. Most of studies in this field focused on prediction of customer churn. Few studies about discovering causes of churn are just about testing primary hypothesis about probable causes. This study because of the shortage of previous studies in this field has made lots of innovations. Some of these innovations are: designing a new framework for discovering causes of churn and designing a hybrid approach from data mining and survey techniques which carried out without benchmarking from any similar study. Proposed framework includes four main steps: feature construction and selection, identification of churners, discovering the causes of churn, and validating the results. Current account customers of Keshavarzi Bank are selected as casestudy of this research and the required data is gathered trough questionnaire. The approach used for discovering causes of churn is extracting the rules which lead to churn in various clusters of customers. For this purpose, decision tree technique with target variable of churn label is utilized. Validating the results is carried out by testing it on validation data set and calculating the top lift and overall error rate. The extracted rules represent that there is a tendency to churn among big segment of keshavarzi's customers. The most important reason (specially among higher salary customers) is about manner of bank agents not reasons expressed by experts such as the way of lending or the profit of backup accounts.

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Human bones experience different modes of loading including tension, compression, bending, and torsion. The modes of loading depend on the activities done by the body. Regarding the crack shape and loading modes, by the time only the first mode of fracture has been studied in order to analyze the fracture toughness. However, it is necessary to analyze different modes of fracture in order to find more reliable results. In this research, finite element analysis and calculations for geometric coefficients were done to obtain the toughness of bone. Hence, first, second, and combined modes of fracture in cortical samples having cracks were studied numerically and experimentally. To this end, bovine tibia was used to make standard tensile samples for implementation in Arkan’s device. Some optimizations were made on the Arcan’s device. These were included of bone fixation in the device and ability of performing tests in different angels. Stress intensity factor (Kc) was obtained for different fracture modes. Results showed a decrease in KIc respect to change in loading angle while KIIc acted vice versa. Performing some extra optimizations, the device can be used for tortional fracture mode in a torsional test device.

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Mechanical behavior of articular cartilage is affected by many factors. Inhomogeneous distribution of proteoglycans and collagen fibers through the thickness causes some depth-wise behavior. Mechanical properties directly affect stress and deformation of the tissue. In previous studies complexities and variation in mechanical properties were ignored. The aim of the present study is to create a model close to real anatomy of articular cartilage in knee joint and to simulate its behavior under dynamic gate in the stance phase. A 3D finite element (FE) model was created. It was constructed considering femur and tibial cartilages as well as medial and lateral meniscus. In the FE model, a nonlinear isotropic viscoelastic material model used for cartilages and a linear anisotropic elastic one was chosen for meniscuses. As well, cartilages assumed saturated . Numerical simulations on the model showed that peak of maximum principal stress occurred in superficial layer. It was decreased through thickness. These expressed why osteoarthritis fall out in the exterior layers such superficial . The present study showed that hydraulic permeability variation in cartilage as a strain-dependent variable was negligible in dynamic loading. Also, results had a good agreement with experimental ones

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Determining how to assess learners and contents of e-learning are essential activities in its processes. These activities are conducted by a professor or teaching assistant and they determine student assessment methods, such as holding an online test or periodic homework assignment. if the organizers can be aware of the effectiveness of each activity in the quality of learning,then besides saving considerable time and resources to stakeholders courses, which transfer the content useful and realistic assessment of students and will ultimately improve e-learning. In this paper, first we use unsupervised techniques of data mining for clustering and describe the present status of learners, and extract hidden rules in e-learning data using rule mining and will discover the effective contents in desired results. Next, using supervised methods we predict results of courses. Using real data of an electronic course provided and with designing four different methods for data sampling and training system, predictions were performed and the methods were validated with an accuracy rate of 92.86%. We have shown that the methods of this study can help teachers for a better understanding of learners and impact of such training activities required, such as describe characteristics of learners based on the discovery of hidden patterns in the scores of their acquired and determine the most effective learning activities and decide about real measures of learners.

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Essential oils and extracts of black cumin have been attracted researchers in the field of protection of raw and processed food due to their antimicrobial and antioxidant compounds. In the current study, the chemical composition, antibacterial and antioxidant properties of black cumin essential oil extracted by Clevenger and ultrasound assisted (frequencies 37 and 80 kHz and 70 and 100% power) methods were performed and the optimization of extraction conditions according to the chemical properties of the essential oil. Antibacterial properties of black cumin essential oil against E.coli and S.aureus were measured by measuring the minimum inhibitory concentration and the minimum lethal concentration of pathogenic bacteria using micro-plate method. The antioxidant activity of essential oil was measured by examining the percentage of DPPH free radical scavenging. The results of analysis of black cumin essential oil by GCMS showed that the main composition of black cumin essential oil extracted by Clevenger method was γ-terpene with 30.03% and in ultrasound method was 31.04%. The highest efficiencies of essential oils and extracts obtained by Clevenger method were 2.04 and 0.75%, respectively, and in ultrasound method (80/100) for essential oils and extracts were 2% and 1%, respectively. The results showed that S.aureus was the most sensitive and E.coli the most resistant bacteria to cumin essential oil. Therefore, it can be stated that the extraction of black cumin essential oil by ultrasound method (80/100) could have the greatest effect on the extraction of essential oils and extracts and can be used to protect food against various systems. Benefit from oxidative and microorganisms that cause infections and food poisoning.

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Petroleum industry of Iran has provided one of the best opportunities for employees, but occupational exposures leading to chronic diseases such as cancer are high in the field. Ministry of Petroleum has owned an organization, which covers the personnel with health insurance, called “Petroleum Industry Health Organization” (PIHO). PIHO and Health, Safety & Environment (HSE) units play significant roles in providing the employees with health services. However, there is lack of a unique system specifying occupational cancer control. Cancer is a major cause of morbidity and mortality worldwide. On the other hand, negative impressions of cancer and heavy costs of patient’s treatment have forced the ministry to pay appropriate attention to this chronic disease. This paper aims to identify structure and design a framework for a system to occupational cancer control in Iranian petroleum industry. Due to the vast dynamic complexities (multi-dimension nature of cancer, joint exposures, and the delay between exposure and incidence) and behavioral complexities (various stakeholders and actors) in the problem, we have adopted Soft System Methodology (SSM) in order to study the current situation. We reached an agreement with the problem owner on a rich picture, CATWOE analysis, and a root definition on how this surveillance system would be considering the real world circumstances.The results were obtained through many sessions with problem stakeholders even with conflicting interests. The results revealed that it is necessary to make some changes in the actors’ information systems (occupational hygiene and medicine, hospitals and the ministry’s Pension Organization), with an emphasis on identifying and analyzing carcinogens and cancer patients in order to improve the problem situation.

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These days, investigation on using acoustofluidic microchannels in separation of microparticles and cells is under consideration. Working under optimum efficiency, these microchannels should be designed and manufactured truly. In this work, a new methodology for designing and manufacturing of acoustofluidic microchannels are explained. Then, a metallic microchannel with 2-nodes of pressure wave based on this method was developed. For mass production purpose, a low cost and reliable method which is CNC micromachining is used. Also, to conduct the heat generated by the wave, this microchannel was made out of aluminum and then polishing technique is applied. Then, the performance of this microchannel in agglomerating of human blood cells and BT-20 breast cancer cells to nodal lines was experimentally studied. The results showed that the applied design and manufacturing technique are suitable. Although some tests were performed to find temperature rise of microchannel due to damping effect, it was found that true design method and also using metals with high thermal conductivity can prevent the temperature increase to the point beyond which living cells will be hurt.

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In the past four decades, new approaches and methodologies have been developed to solve unstructured and messy problems with various stakeholders. Among these methods, soft system methodologies, cognitive mapping, and strategic choice approach are specifically worthy to be heeded. The methods mentioned above, which have a precise structure and clear framework, are often categorized as soft operations research or problem structuring methods. Today, there is ample literature on soft research and it is taught in many operations research/management science courses of reputable universities. Methods of research on soft OR are rooted in soft system thinking and belong to the interpretative/learning paradigm. Nonetheless, assigning a clear and precise boundary between hard and soft OR techniques is not easily feasible, for most of these techniques– based on their application in different situations – can be classified as both hard and soft. The aim of this research is to investigate the origins and current position of soft methodology of operations research and probe into its theoretical basis. A comparison between the trend of OR in the US and UK clearly demonstrates the differences in soft and hard approaches. Generally, it can be concluded that soft and hard approaches of OR are complementary: soft methods are exploited in forming the structure (configuration) of a problem and hard methods are utilized in solving it.
 
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