Showing 127 results for zarei
Volume 24, Issue 10 (October 2024)
Abstract
This article focuses on the design, manufacturing, and dynamic modeling of a piezoelectric pneumatic servo valve based on a compliant mechanism. The use of piezoelectric actuators in these valves, due to their fast dynamic response and high precision, significantly improves the speed of pressure control. To this end, the structure of the pneumatic servo valve and the function of its components were initially investigated. To enhance the valve's orifice opening, a rhombus type compliant mechanism was designed to amplify the displacement range of the piezoelectric actuator. Subsequently, a comprehensive dynamic model of the system was presented. After identification and validating the proposed dynamics, the results of air pressure control for both steady and time-varying reference inputs were provided. Experimental results indicate that the proposed dynamic model for the manufactured valve has a maximum error of 25%. Additionally, frequency analysis results show that the valve has a dynamic bandwidth of 90 Hz and a natural frequency of 56 Hz, highlighting its applicability for high-frequency operations. The results of pressure control demonstrate a step response time of approximately 21 milliseconds at a pressure of 2 bar, indicating its capability to respond to rapid pressure changes. Furthermore, the ability to track input pressures with varying frequencies and amplitudes was also evaluated
Volume 25, Issue 2 (7-2021)
Abstract
In the organizational world, women have more opportunities to participate and compete with men. Despite the increasing participation of women in organizations, the advancement and entry of women into high positions faces obstacles known as the glass ceiling. In this regard, the present study was conducted with the aim of identifying barriers to the promotion of women using the qualitative Q method in the National Iranian Oil Company. Q statement were explored through 19 selected studies based on research protocols and media sources such as publications, newspapers, television programs, and conversations with experts and elites. Then, a questionnaire consisting of 39 cards and an answer sheet (Q diagram) was given to 43 experts who expressed their opinion based on a range of strongly agree (+4) to strongly disagree (4-). The collected data were analyzed by Q-type explorative factor analysis using SPSS software. The results showed that there are seven perceptions and mental groups about the obstacles faced by women in achieving managerial positions. In these mental models, the statements “less skill of women in political games”, “less ability of women to bear the psychological pressures of managerial jobs”, “family priority over work for women”, “Womenchr('39')s dependence on men in terms of geography and place of residence” “need a flexible work plan” were among the most important barriers to womenchr('39')s career advancement.
Volume 25, Issue 2 (Spring 2022)
Abstract
Deep brain stimulation (DBS) stands as an alternative treatment for drug-resistant temporal lobe epilepsies. In this study, we investigated the effects of both low- and high-frequency stimulation (LFS and HFS) of the olfactory bulb on locomotor activity and preferences for spending time in the central or border regions. Rats underwent a kindling procedure involving semi-rapid electrical stimulation (6 stimulations per day) of the hippocampal CA1 region. Fully kindled animals received LFS (1 Hz) or HFS (130 Hz) at four time points: 5 min, 6 h, 24 h, and 30 h after the last kindling stimulation. Subsequently, rats were placed in the open field chamber and allowed free, uninterrupted movement within the respective quadrant of the maze for a single 10-minute period. During this time, tracking software recorded movement, and locomotor activity as well as preferences for spending time in the central or border regions were evaluated. Overall, applying DBS in the olfactory bulb at both low and high frequencies decreased exploration time in the center and increased exploration time in the border for the rats. Furthermore, a higher intensity of HFS was more effective than a lower intensity of HFS in reducing anxiety or altering locomotor behavior. According to the results of the present study it may be suggested that applying DBS affects some aspects of the animals’ activity and therefore, the activity monitoring tests have to be done following DBS application.
Volume 26, Issue 2 (Spring 2023)
Abstract
The escalating incidence of foodborne diseases caused by pathogenic bacteria presents a substantial global health concern. Microbial spoilage of food not only shortens product shelf life but also increases the risk of foodborne diseases. According to the World Health Organization, one in ten people worldwide falls ill after consuming contaminated food. While foodborne diseases are preventable, the implementation of effective strategies to control and prevent these illnesses remains a critical global challenge. The unique properties of both organic and inorganic nanoparticles have attracted significant attention in the food industry due to their potential to enhance nutritional, safety, and quality attributes of food products. A majority of foodborne infections are attributed to pathogens such as Salmonella, Listeria, Escherichia coli, Clostridium, and Campylobacter. Silver and silver-based compounds have been shown to exhibit potent antimicrobial activity against a broad spectrum of bacteria. The current body of knowledge regarding the application of silver nanoparticles for the elimination of foodborne pathogens is expanding rapidly, providing opportunities to explore their mechanisms of action, benefits, and limitations. This perspective aims to identify novel strategies for reducing the burden of foodborne diseases by critically evaluating the potential of silver nanoparticles. Furthermore, the potential health implications of silver nanoparticles for human consumption will be discussed to inform the development of effective policies for public health.
Volume 30, Issue 2 (Summer 2023)
Abstract
The main purpose of this paper is to identify the vocational support methods for new teachers worldwide. In this qualitative research with the emergence design, the technique of thematic analysis (Attride-Stirling) was used to analyze the themes of English papers on the Induction published from 2010 to 2020, and selected from three data-bases by using a systematic text review model. After using the MAXQDA software, the data were analyzed in the form of two comprehensive, six organized, and 29 basic themes. The results show that the informal Induction for new teachers includes two components of "out-school support" and "in-school support" that complement each other. The vocational support has made teachers more resilient and efficient. Accordingly, it is suggested that our new teachers and educational system use this global experience and to increase the efficiency and sustainability of new teachers, there capacities should be utilized in the communication networks of their living and working environment.
Volume 30, Issue 3 (6-2023)
Abstract
Glassmaking traces its history back to antiquity as is the case with several other crafts in Iran. The craft would culminate under the Sassanian rule, when an assortment of receptacles in different sizes, shapes, and functions came into popular use. The present study examines a sample of 29 pieces of Sassanian glass objects preserved in the Sanandaj Archaeological Museum. Deriving from clandestine excavations, no previous research has investigated these pieces. This descriptive and historical-analytical study draws upon comparisons with related museum objects and library research. The questions are: Which excavated sites in the Sassanian territory are to be examined for comparanda? What are the manufacturing techniques of the objects in question? To which part of the Sassanian time span do they date? What are the common forms as well as their functions and decorations? The sample appears to compare with the material from Mesopotamia (Tell Mahuz, Abu Skhair, Barghuthiat, and Kish) and Veh Ardashir, which were major centers of glass production at the time. The pieces were manufactured in free-blowing and mold-blowing techniques. Bowls are the common form, followed by bottles, unguentaria, juglets, and jars for ritual, cosmetic, and practical functions. The major decorations detected on the study sample include applied trails and facet cutting. The pieces can be assigned to two consecutive chronological extents: The first spans the onset of the Sassanian period (2nd century AD) to the 4th century AD, and the second encompasses the 4th century AD to the demise of the empire. Dispersion of such objects across the Sassanian Empire suggests that glassware represented a trade item at that time.
Volume 31, Issue 4 (11-2024)
Abstract
Clifford Geertz, one of the most prominent ideologues of the interpretative approach to religion and culture, is recognized as one of the most influential cultural anthropologists of the twentieth century in America. Geertz's approach is considered one of the most significant in the postmodern era. This paper, utilizing a descriptive-analytical method and, in some cases, content analysis, provides a brief overview of the meaning of culture from Geertz's perspective and its characteristics. It also offers a comprehensive and accurate portrayal of his views on religion, demonstrating that, from Geertz's standpoint, religion is akin to a cultural system and is closely associated with culture in its meaning, features, and anthropological significance. In Geertz's thought, culture and religion are intertwined. He believes that to understand culture, one must delve into symbols; rituals and religious activities are considered symbols. He sees religion as an ancient aspect of the larger culture of society, where the presence of rituals and numerous beliefs renders it symbolic. One of the essential concepts in Geertz's thought is "meaning," primarily because meanings form a closely related system, which is culture itself. One of the most important effects of the cultural approach to religion is the understanding of religion from the perspective of the modern subject and the transition from it. As this methodology reveals the understanding of religion in the modern period, it serves as a starting point for postmodern methodology in the study of religions, positioning itself as a vanguard in the future of religious studies.
