Search results for: Mahsa Khajavi

Authors: Gelareh Changizi, Mahsa Khajavi, Ladan Shahhosseini

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Corporate-level strategy, or simply ‘parent strategy’, is a topic that has received much attention since the very early days of the strategic planning field. Since the multi level enterprises have different sub enterprises which deal with different business environments, we cannot define the same strategic perspective for all of them. Therefore, the determination of a perspective to manage and deal with affiliates of such enterprises is the main challenge. The parent strategy in mother enterprises' level has been analyzed in this research. A case study has been carried to comprehensively describe the proposed model.

Keywords: parent strategy, multi-business companies, performance evaluation, lifecycle

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Authors: Nimmy Maria Joseph, Muhammed Hafiludheen

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On September 16, a 22-year-old Iranian woman, Mahsa Amini, died in Tehran after she was arrested by the ‘Morality police’ for an accusation of not wearing a hijab according to the standards laid down by the Iran Government. Suspicions aroused as the incident happened while Mahsa Amini was under the custody of Iran police. People of Iran accused that she was severely beaten up by the police, which led to her death. This initiated an array of women-led protests in Iran, leading to the ignition of massive uproars in the country. The Law Enforcement Command of Iran reported that she collapsed due to a heart attack and not due to police brutality. However, as a result, Iran faced a series of conflicts between the Government of Iran and the civilians, especially women. The research paper presents the framing analysis of online news stories on Mahsa Amini’s death and the resultant protest in Iran. The researcher analysed the online news stories of two popular newspapers, Tehran Times (Iran) and The Wall Street Journal (USA). The focus of the study is to have a comparative analysis of the frames of the news stories used and find out their agenda-setting pattern. It helps to comprehend how the news stories of popular news organisations try to channelise the perception of their audience on social issues. The researcher analysed the news stories considering their frames, valence, polysemy, rhetoric devices, and technical devices.

Keywords: mahsa amini, iran protest, framing analysis, valence, rhetoric device, tehran times, the wall street journal

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Authors: Sofia Ahanj Sofia Ahanj, Mahsa Rahmani Mahsa Rahmani, Zahra Sadeghigol, Vida Nobakht Vida Nobakht

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Providing security in the electricity industry, as one of the vital infrastructures of the country, is one of the essential operations that must be taken in order to improve the security of the country. Resistant security strategies need to be regularly implemented as a dynamic process to improve security, and security evaluation is one of the most important steps in this process. Methodology in the field of evaluation in both technical and managerial dimensions is discussed in the laboratory. There are various standards in the field of general ICT technical-security evaluation. The most important are ISO / IEC 15408, ISO / IEC 27001 and NIST SP 800-53. In the present paper, these standards are first examined. Then, the standards and reports in the industrial field have been reviewed and compared, and finally, based on the results and special considerations of information and communication technology equipment in the electricity industry, the appropriate methodology has been presented.

Keywords: security standards, ISO/IEC 15408, ISA/IEC 62443 series, NIST SP 800-53, NISTIR 7628

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Authors: Farzad Khajavi, Farzaneh Jalilfar, Faranak Jafari, Leila Shokrani

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Formulation of Ranolazine in the form of extended-release tablet in 500 mg dosage form was performed using Eudragit L100-55 as a retarding agent. Drug-release profiles were investigated in comparison with the reference Ranexa extended-release 500 mg tablet. F₂ and f₁ were calculated as 64.16 and 8.53, respectively. According to Peppas equation, the release of drug is controlled by diffusion (n=0.5). The tablets were put into accelerated stability conditions (40 °C, 75% humidity) for 3 and 6 months. The dissolution release profiles and other physical and chemical characteristics of the tablets confirmed the robustness and stability of formulation in this condition.

Keywords: drug release, extended-release tablet, ranolazine, stability

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Authors: Mehrdad Nouri Khajavi, Gollamhassan Payganeh, Mohsen Fallah Tafti

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Fault diagnosis is an important aspect of maintaining rotating machinery health and increasing productivity. Many researches has been done in this regards. Many faults such as unbalance, misalignment, looseness, bearing faults, etc. have been considered and diagnosed with different techniques. Most of the researches in fault diagnosis of rotating machinery deal with single fault. Where as in reality faults usually occur simultaneously and it is, therefore, necessary to recognize them at the same time. In this research, two of the most common faults namely unbalance and misalignment have been considered simultaneously with different intensity and then identified and classified with the use of Multi-Layer Perception Neural Network (MLPNN). Processed Vibration signals are used as the input to the MLPNN, and the class of mixed unbalancy, and misalignment is the output of the NN.

Keywords: unbalance, parallel misalignment, combined faults, vibration signals

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Authors: H. Samadiyeh, R. Khajavi

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A new FD-based procedure, modal finite difference method (MFDM), is proposed for seismic wave propagation modeling, in which simulation is dealt with in the modal space. The method employs eigenvalues of a characteristic matrix formed by appropriate time-space FD stencils. Since MFD runs for different modes are totally independent of each other, MFDM can easily be parallelized while considerable simplicity in parallel-algorithm is also achieved. There is no requirement to any domain-decomposition procedure and inter-core data exchange. More important is the possibility to skip processing of less-significant modes, which enables one to adjust the procedure up to the level of accuracy needed. Thus, in addition to considerable ease of parallel programming, computation and storage costs are significantly reduced. The method is qualified for its efficiency by some numerical examples.

Keywords: Finite Difference Method, Graphics Processing Unit (GPU), Message Passing Interface (MPI), Modal, Wave propagation

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Authors: Seifoddini Hamid, Mardikoraeem Mahsa, Ghorayshi Roya

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Manufacturing facility location selection is an important strategic decision for many industrial corporations. In this paper, a new approach to the manufacturing location selection problem is proposed. In this approach, cluster analysis is employed to identify suitable manufacturing locations based on economic, social, environmental, and political factors. These factors are quantified using the existing real world data.

Keywords: manufacturing facility, manufacturing sites, real world data

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Authors: Amin Ranjbar, Amir Arsalan Jalili Zolfaghari, Amir Abolfazl Suratgar, Mehrdad Khajavi

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This paper describes two stages of learning-based fault detection procedure in alternators. The procedure consists of three states of machine condition namely shortened brush, high impedance relay and maintaining a healthy condition in the alternator. The fault detection algorithm uses Wigner-Ville distribution as a feature extractor and also appropriate feature classifier. In this work, ANN (Artificial Neural Network) and also SVM (support vector machine) were compared to determine more suitable performance evaluated by the mean squared of errors criteria. Modules work together to detect possible faulty conditions of machines working. To test the method performance, a signal database is prepared by making different conditions on a laboratory setup. Therefore, it seems by implementing this method, satisfactory results are achieved.

Keywords: alternator, artificial neural network, support vector machine, time-frequency analysis, Wigner-Ville distribution

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Authors: Farzad Khajavi, Farzaneh Jalilfar, Faranak Jafari, Leila Shokrani

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Formulation of gliclazide in the form of extended-release tablet in 30 and 60 mg dosage forms was performed using hypromellose (HPMC K4M) as a retarding agent. Drug-release profiles were investigated in comparison with references Diamicron MR 30 and 60 mg tablets. The effect of size of powder particles, the amount of hypromellose in formulation, hardness of tablets, and also the effect of halving the tablets were investigated on drug release profile. A mathematical model which describes hypromellose behavior in initial times of drug release was proposed for the estimation of hypromellose content in modified-release gliclazide 60 mg tablet. This model is based on erosion of hypromellose in dissolution media. The model is applicable to describe release profiles of insoluble drugs. Therefore, by using dissolved amount of drug in initial times of dissolution and the model, the amount of hypromellose in formulation can be predictable. The model was used to predict the HPMC K4M content in modified-release gliclazide 30 mg and extended-release quetiapine 200 mg tablets.

Keywords: Gliclazide, hypromellose, drug release, modified-release tablet, mathematical model

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Authors: Mahsa Karimpour, Martin Belusko, Ke Xing, Frank Bruno

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Traditionally the embodied energy of design choices which reduce operational energy were assumed to have a negligible impact on the life cycle energy of buildings. However with new buildings having considerably lower operational energy, the significance of embodied energy increases. A life cycle assessment of a population of house designs was conducted in a mild and mixed climate zone. It was determined not only that embodied energy dominates life cycle energy, but that the impact on embodied of design choices was of equal significance to the impact on operational energy.

Keywords: building life cycle energy, embodied energy, energy design measures, low energy buildings

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Authors: Farzad Khajavi

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Recognition of the interaction between active pharmaceutical ingredients (API) and excipients is a pivotal factor in the development of all pharmaceutical dosage forms. By predicting the interaction between API and excipients, we will be able to prevent the advent of impurities or at least lessen their amount. In this study, we used principle component analysis (PCA) to predict the interaction between Gliclazide as a secondary amine with Lactose in pharmaceutical solid dosage forms. The infrared spectra of binary mixtures of Gliclazide with Lactose at different mole ratios were recorded, and the obtained matrix was analyzed with PCA. By plotting score columns of the analyzed matrix, the incompatibility between Gliclazide and Lactose was observed. This incompatibility was seen experimentally. We observed the appearance of the impurity originated from the Maillard reaction between Gliclazide and Lactose at the chromatogram of the manufactured tablets in room temperature and under accelerated stability conditions. This impurity increases at the stability months. By changing Lactose to Mannitol and using Calcium Dibasic Phosphate in the tablet formulation, the amount of the impurity decreased and was in the acceptance range defined by British pharmacopeia for Gliclazide Tablets. This method is a fast and simple way to predict the existence of incompatibility between excipients and active pharmaceutical ingredients.

Keywords: PCA, gliclazide, impurity, infrared spectroscopy, interaction

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Authors: Abbas Rezaei Samarin

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In October 2022, protests began following the death of Mahsa Amini and were followed by the deaths of those arrested by Iran's morality police which Iran's official media and foreign Persian-language satellite channels presented to the audience different narratives of how they were killed. These two types of media produced two different and sometimes conflicting narratives when faced with the news of a certain person's death, and the conflict is found between the narratives in some cases. This study has focused on the semiotics of these narratives, the interpretation of discourses supporting the narratives, and finally, their analysis within the framework of narrative theories. In the present study, the researcher has used a qualitative approach and has concluded that the narrative of both types of media is structured around the functions of the existing and ideal political system.

Keywords: narrative, iran, fake news, protests, manipulation of reality

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Authors: Farzad Khajavi

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Studies about the interaction between active pharmaceutical ingredients (API) and excipients are so important in the pre-formulation stage of development of all dosage forms. Analytical techniques such as differential scanning calorimetry (DSC), Thermal gravimetry (TG), and Furrier transform infrared spectroscopy (FTIR) are commonly used tools for investigating regarding compatibility and incompatibility of APIs with excipients. Sometimes the interpretation of data obtained from these techniques is difficult because of severe overlapping of API spectrum with excipients in their mixtures. Principal component analysis (PCA) as a powerful factor analytical method is used in these situations to resolve data matrices acquired from these analytical techniques. Binary mixtures of API and interested excipients are considered and produced. Peaks of FTIR, DSC, or TG of pure API and excipient and their mixtures at different mole ratios will construct the rows of the data matrix. By applying PCA on the data matrix, the number of principal components (PCs) is determined so that it contains the total variance of the data matrix. By plotting PCs or factors obtained from the score of the matrix in two-dimensional spaces if the pure API and its mixture with the excipient at the high amount of API and the 1:1mixture form a separate cluster and the other cluster comprise of the pure excipient and its blend with the API at the high amount of excipient. This confirms the existence of compatibility between API and the interested excipient. Otherwise, the incompatibility will overcome a mixture of API and excipient.

Keywords: API, compatibility, DSC, TG, interactions

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Authors: Mahsa Mahjoub Laleh, Nasser Dasht Peyma

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This paper explores Marie Jones’s Stones in His Pockets in the light of the postcolonial notion of hybridity. The play is a tragicomedy about a small village in Ireland where many of the locales are extras in a Hollywood film. The actions of the play revolve around a local teenager named Sean who has been vilipended by a famous film star. The Sean character commits suicide by drowning himself with stones in his pockets. This paper explored how the attempts to gain cultural identity is manifested in Marie Jones’s play and how authority causes a change in the culture and destiny of people. Apparently, the play demonstrates that the political, economic and social realities directly affect people’s destiny and identity.

Keywords: cultural identity, hybridity, identity, postcolonial

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Authors: Mahsa Moteshakeri

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Morinda citrifolia L., a miracle fruit with common name of Noni, has been widely used as food and traditional medicine in the Polynesians culture. Current scientific evidences have proved the therapeautical and nutritional properties of this fruit so that its extensive production in tropical regions in recent years has emerged a competitive global Noni market mainly as a dietary supplement in the form of juice or tablet. However, there is not much record on the processing method applied on fresh fruit postharvest or even its mechanism of action in controlling diseases. This review aimed to provide a comprehensive data on phytochemicals, technical, and nutritional advances on Noni fruit and recent patents published, as well as medicinal properties of the fruit in order to benefit future investigations on this precious fruit either in industrial or therapeautical section.

Keywords: noni fruit, phytochemicals, therapeautic properties of fruit, nutritional properties of fruit

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Authors: Shirin Arefi

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In Iran, women and girls are treated as second class citizens and suffer from many discrimination and inequality such as compulsory Hejab, a phenomena which has required all women to wear the hijab head-covering since the 1979 Islamic revolution. Now, the crackdown of new government has caused a massive uproar in the country. The morality police also continue to curb the choices of women, and the latest unfortunate incidents accelerate the hardened rules. The author is going to survey the views and of women against compulsory Hejab and morality and chastity police arrests. The methodology is a qualitative one in which narratives of them are coded based on grounded theory and horizons of the process is explained by phenomenological research as well. The findings and results will show the current attitudes of women of Hejab and their reactions against morality police behaviors.

Keywords: compulsory hejab, morality police, people, arrest

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Authors: Mahsa Ja’fari, Mohammad R. Khosravi-Nikou, Mohsen Motavassel

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A comprehensive development towards the production of ultra-clean fuels as a feed stoke is getting to raise due to the increasing use of diesel fuels and global air pollution. Production of environmental-friendly fuels can be achievable by some limited single methods and most integrated ones. Oxidative desulfurization (ODS) presents vast ranges of technologies possessing suitable characteristics with regard to the Fenton process. Using toluene as a model fuel feed with dibenzothiophene (DBT) as a sulfur compound under various operating conditions is the attempt of this study. The results showed that this oxidative process followed a pseudo-first order kinetics. Removal efficiency of 77.43% is attained under reaction time of 40 minutes with (Fe⁺²/H₂O₂) molar ratio of 0.05 in acidic pH environment. In this research, temperature of 50 °C represented the most influential role in proceeding the reaction.

Keywords: design of experiment (DOE), dibenzothiophene (DBT), optimization, oxidative desulfurization (ODS)

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Authors: Mahsa Mafi

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Encapsulation of Micrococcus Luteus (M. Luteus) in polymeric composites has been employed for the bioremediation, sequestration of metals and for the biodegradation of chemical pollutants and toxic components in waste water. Polymer composites in the form of nonwovens of nanofibers, or core/shell particles can provide a bacterial friendly environment for transfer of nutrients and metabolisms, with the least leakage of bacteria. M. Luteus is encapsulated in a hydrophilic core of poly (vinyl alcohol), following by synthesis or coating of a proper shell as a support to maintain the chemical and mechanical strength. The biological activity of bacteria is confirmed by Live/Dead analysis and agar plate tests. SEM and TEM analysis were utilized for morphological studies of polymer composites. As a result of the successful encapsulation of the alive bacteria in polymers, longer storage time in their functional state were achieved.

Keywords: Polymer composites, Bacteria encapsulation, Bioremediation, Waste water treatment

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Authors: Mazyar Ahrari, Ramin Khajavi, Mehdi Kamali Dolatabadi, Tayebeh Toliyat, Abosaeed Rashidi

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Fabric as the first and most common layer that is in permanent contact with human skin is a very good interface to provide coverage, as well as heat and cold insulation. Phase change materials (PCMs) are organic and inorganic compounds which have the capability of absorbing and releasing noticeable amounts of latent heat during phase transitions between solid and liquid phases at a low temperature range. PCMs come across phase changes (liquid-solid and solid-liquid transitions) during absorbing and releasing thermal heat; so, in order to use them for a long time, they should have been encapsulated in polymeric shells, so-called microcapsules. Microencapsulation and nanoencapsulation methods have been developed in order to reduce the reactivity of a PCM with outside environment, promoting the ease of handling, decreasing the diffusion and evaporation rates. Methods of incorporation of PCMs in textiles such as electrospinning and determining thermal properties had been summarized. Paraffin waxes catch a lot of attention due to their high thermal storage density, repeatability of phase change, thermal stability, small volume change during phase transition, chemical stability, non-toxicity, non-flammability, non-corrosive and low cost and they seem to play a key role in confronting with climate change and global warming. In this article, we aimed to review the researches concentrating on the characteristics of PCMs and new materials and methods of microencapsulation.

Keywords: thermoregulation, microencapsulation, phase change materials, thermal energy storage, nanoencapsulation

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Authors: Mahsa Ghorbani Jazin

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The insurance industry has a prominent place in the economy of every country in the world. Fire insurance policies are types of non-life insurance, which protect insureds against financial losses of fire and related risks. In this paper, factors that are affecting the demand for fire insurance in Iran have been examined. Due to this reason, information and data have been collected during the period 1989-2019. In this research, the final model was estimated. The obtained results represent that as the population and literacy rate increase, people are more willing to purchase fire insurance. On the other hand, the actual per capita income has a negative influence on the demand for this type of insurance. Also, the amount of compensation that is paid in losses can be assumed as an indirect advertisement for fire insurance and attracts people to buy this policy. Finally, the new technology in the insurance industry is examined as a new underestimated way for increasing demand, especially in Iran.

Keywords: fire insurance, demand, per capita income, literacy rate, population, compensation paid, Insurtech

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Authors: M. N. Khajavi, S. Nasiri, E. Farokhi, M. R. Bavir

Abstract:

Alcohol fuels are renewable, have low pollution and have high octane number; therefore, they are important as fuel in internal combustion engines. Percentage detection of these alcoholic fuels with gasoline is a complicated, time consuming, and expensive process. Nowadays, these processes are done in equipped laboratories, based on international standards. The aim of this research is to determine percentage detection of different fuels based on vibration analysis of engine block signals. By doing, so considerable saving in time and cost can be achieved. Five different fuels consisted of pure gasoline (G) as base fuel and combination of this fuel with different percent of ethanol and methanol are prepared. For example, volumetric combination of pure gasoline with 10 percent ethanol is called E10. By this convention, we made M10 (10% methanol plus 90% pure gasoline), E30 (30% ethanol plus 70% pure gasoline), and M30 (30% Methanol plus 70% pure gasoline) were prepared. To simulate real working condition for this experiment, the vehicle was mounted on a chassis dynamometer and run under 1900 rpm and 30 KW load. To measure the engine block vibration, a three axis accelerometer was mounted between cylinder 2 and 3. After acquisition of vibration signal, eight time feature of these signals were used as inputs to an Adaptive Neuro Fuzzy Inference System (ANFIS). The designed ANFIS was trained for classifying these five different fuels. The results show suitable classification ability of the designed ANFIS network with 96.3 percent of correct classification.

Keywords: internal combustion engine, vibration signal, fuel composition, classification, ANFIS

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Authors: Mahsa Faramarzi Asli, Mina Sarabi

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The important issues that are addressed in most advanced industrial countries in recent decades, discussion of minimizing heat losses through the buildings. And the most influential parameters in the calculation of building energy consumption, is heat exchange, which takes place between the interior and outer space. One of the solutions to reduce heat loss is using materials with low thermal conductivity. The purpose of this article, is the effect of using some frontages with nano-concrete photo catalytic precast materials for reducing energy consumption in buildings. For this purpose, estimating the energy dissipation through the facade built with nano-concrete photo catalytic precast materials on a sample building in Tabriz city by BCS 19 software ( topic 19 simulation) is done and the results demonstrate reduce heat loss through the facade nano- concrete.

Keywords: nano materials, optimize energy consumption, themal, stability

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Authors: Sajad Shokohuyar, Mahsa Zomorrodi Anbaji, Saghar Pouyan Shad

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According to fast technology growth, modern banking tries to decrease going to banks’ branches and increase customers’ consent. One of the problems which banks face is securing customer’s password. The banks’ solution is one time password creation system. In this research by adapting from acceptance of technology model theory, assesses factors that are effective on banking in Iran especially in using one time password machine by one of the private banks of Iran customers. The statistical population is all of this bank’s customers who use electronic banking service and one time password technology and the questionnaires were distributed among members of statistical population in 5 selected groups of north, south, center, east and west of Tehran. Findings show that confidential preservation, education, ease of utilization and advertising and informing has positive relations and distinct hardware and age has negative relations.

Keywords: security, electronic banking, one time password, information technology

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Authors: Amir Masoud Dabagh, Mahsa Khaleghi

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The world has entered a new phase of cultural, social, economic, and so on in the last two centuries. Apart from its positive benefits and achievements to the world, it has also incurred many costs, most of which can be mentioned as destroying or at least diminishing the role of the costumes, traditions and authentic culture of the past communities. Understanding what lasts in traditional arts is vital and worthy of study because receiving it and embracing art and forms of art using that last the artistic creation removes the age-old color and smell of its face, making it immortal and persistent in all ages. This paper attempts to present traditional art concepts and solutions for interior design with the approach of handicrafts recreation as a symbol and manifestation of national identity and proof of ancient civilizations, which is at the center of tourists' attention today. The research method is a descriptive-analytical one that first explores the theoretical foundations of research, which are the concepts of recreation and traditional arts, and analyzes the process of recreation that conceals the recollection of past experiences as well as the dynamics and creativity.

Keywords: recreation, handicrafts, interior design, concept, traditional arts

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Authors: Mahsa Pishdar

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Food traceability through the supply chain is facing increased demand. IoT and blockchain are among the tools under consideration in the Industry 4.0 era that could be integrated to help implementation of the Circular Economy (CE) principles while enhancing food traceability solutions. However, such tools need intellectual system, and infrastructureto be settled as guidance through the way, helping overcoming obstacles. That is why the critical success factors for implementing Industry 4.0 and circular economy principles in food traceability concept are analyzed in this paper by combination of interval type 2 fuzzy Worst Best Method and Measurement Alternatives and Ranking according to Compromise Solution (Interval Type 2 fuzzy WBM-MARCOS). Results indicate that “Knowledge of Industry 4.0 obligations and CE principle” is the most important factor that is the basis of success following by “Management commitment and support”. This will assist decision makers to seize success in gaining a competitive advantage while reducing costs through the supply chain.

Keywords: food traceability, industry 4.0, internet of things, block chain, best worst method, marcos

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Authors: Mahsa Mahtab, Morteza Habibi

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The effect of different anode tip geometries on the intensity of soft and hard x-ray emitted from a 4 kJ plasma focus device is investigated. For this purpose, 5 different anode tips are used. The shapes of the uppermost region of these anodes have been cylindrical-flat, cylindrical-hollow, spherical-convex, cone-flat and cone-hollow. Analyzed data have shown that cone-flat, spherical-convex and cone-hollow anodes significantly increase X-ray intensity respectively in comparison with cylindrical-flat anode; while the cylindrical-hollow tip decreases. Anode radius reduction at its end in conic or spherical anodes enhance SXR by increasing plasma density through collecting a greater mass of gas and more gradual transition phase to form a more stable dense plasma pinch. Also, HXR is enhanced by increasing the energy of electrons colliding with the anode surface through raise of induced electrical field. Finally, the cone-flat anode is introduced to use in cases in which the plasma focus device is used as an X-ray source due to its highest yield of X-ray emissions.

Keywords: plasma focus, anode tip, HXR, SXR, pinched plasma

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Authors: Mahsa Namvari, Kari Ullakko

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It is well-known that the Co-doping of ferromagnetic shape memory alloys (FSMAs) is a crucial tool to control their multifunctional properties. The present work investigates the use of small quantities of Co to fine-tune the transformation, structure, microstructure, mechanical and magnetic properties of the polycrystalline Ni₄₉.₈Mn₂₈.₅Ga₂₁.₇ (at.%) alloy, At Co concentrations of 1-1.5 at.%, a microstructure with an average grain size of about 2.00 mm was formed with a twin structure, enabling the experimental observation of magnetic-field-induced twin variant rearrangement. At higher levels of Co-doping, the grain size was essentially reduced, and the crystal structure of the martensitic phase became 2M martensite. The decreasing grain size and changing crystal structure are attributed to the progress of γ-phase precipitates. Alongside the academic aspect, the results of the present work point to the commercial advantage of fabricating 10M Co-doped Ni-Mn-Ga actuating elements made from large grains of polycrystalline ingots obtained by a standard melting facility instead of grown single crystals.

Keywords: Ni-Mn-Ga, ferromagnetic shape memory, martensitic phase transformation, grain growth

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Authors: Maryam Azimi, Amin Banitalebi-Dehkordi, Yuanyuan Dong, Mahsa T. Pourazad, Panos Nasiopoulos

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While there exists a wide variety of Low Dynamic Range (LDR) quality metrics, only a limited number of metrics are designed specifically for the High Dynamic Range (HDR) content. With the introduction of HDR video compression standardization effort by international standardization bodies, the need for an efficient video quality metric for HDR applications has become more pronounced. The objective of this study is to compare the performance of the existing full-reference LDR and HDR video quality metrics on HDR content and identify the most effective one for HDR applications. To this end, a new HDR video data set is created, which consists of representative indoor and outdoor video sequences with different brightness, motion levels and different representing types of distortions. The quality of each distorted video in this data set is evaluated both subjectively and objectively. The correlation between the subjective and objective results confirm that VIF quality metric outperforms all to their tested metrics in the presence of the tested types of distortions.

Keywords: HDR, dynamic range, LDR, subjective evaluation, video compression, HEVC, video quality metrics

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Authors: Mehdi Sheikhi, Marjan Nassiri-Asl, Esmail Abbasi, Mahsa Shafiee

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Various synthetic derivatives of natural flavonoids are known to have neuroactive properties. The present study aimed to investigate the effects of vitexin (5, 7, 4-trihydroxyflavone-8-glucoside), a flavonoid found in such plants as tartary buckwheat sprouts, wheat leaves phenolome, Mimosa pudica Linn and Passiflora spp, on scopolamine-induced memory impairment in rats. To achieve this goal, we assessed the effects of vitexin on memory retrieval in the presence or absence of scopolamine using a step-through passive avoidance trial. In the first part of the study, vitexin (25, 50, and 100 μM) was administered intracerebroventricularly (i.c.v.) before acquisition trials. In the second part, vitexin, at the same doses, was administered before scopolamine (10 μg, i.c.v.) and before the acquisition trials. During retention tests, vitexin (100 μM) in the absence of scopolamine significantly increased the stepthrough latencies compared to scopolamine. In addition, vitexin (100 μM) significantly reversed the shorter step-through latencies induced by scopolamine (P < 0.05). These results indicate that vitexin has a potential role in enhancing memory retrieval. A possible mechanism is modulation of cholinergic receptors; however, other mechanisms may be involved in its effects in acute exposure.

Keywords: flavonoid, memory retrieval, passive avoidance, scopolamine, vitexin

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Authors: Mahsa Kangazian Kangazi, Ali Akbar Ghareh Aghaji, Majid Montazer

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Nowadays, silica nanofibers are highly regarded among the inorganic nanofibers due to the high reactivity and availability of silicon compounds in nature. Sol-gel process is required for electrospinning of silica nanofibers in which a metal alkoxide is hydrolyzed, and the viscosity is increased. In this study, silica nanofibers containing silver nanoparticles were synthesized and electrospun from a mixture of silica sol with an easy spinnable polymer (PVA) as an additive. The silica sol contains tetraethyl orthosilicate (TEOS), silver nitrate, distilled water, nitric acid, and ethanol. Nanofibers were formed through electrospinning setup. The nanofibers were calcinated to remove the solvent and additive polymer. Consequently, pure silica nanofibers were produced. FTIR analysis indicated entire removal of polyvinyl alcohol from the structure and formation of silan groups. The presence of silver, silica and oxygen was confirmed by EDX. Also, XRD patterns revealed the presence of silver nanoparticles with a mean crystal size of 18 nm. FESEM images showed that adding silver nitrate into the sol-gel, resulted in lower nanofibers diameter from 286 to 136 nm. Furthermore, the electrospun nanofibers were more resistance in acidic media than alkaline media.

Keywords: in situ synthesis of silver nanoparticles, silica nanofibers, sol-gel, tetraethyl orthosilicate

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