Showing 19 results for Delavar
Volume 0, Issue 0 (Articles accepted at the time of publication 2024)
Abstract
Over the past decades, research on language teacher engagement in action research (AR) has received a surge of interest. However, little research is available on how teachers’ experience contribute to their development of agency and professional performances through their participation in an AR program. Accordingly, this study explored the role of experience in five novice and five experienced language teachers’ development of agency and practice before, during, and after their engagement in an action research engagement program (AREP). To this end, we collected data via semi-structured interviews, reflective journals, and classroom observations. The findings revealed that novice and experienced teachers’ development of their agency and professional practice undergo similar trajectories. Moreover, the study argues that although experience affects teacher-researchers’ agentive role and performances, novice and experienced teachers go through similar paths as they engage in AR. However, the novice teachers became more oriented towards reflection-in-action during and after their engagement in AREP. Moreover, the novice teachers chose more AR tools and drew more on their AR experience which, in turn, facilitated their professional growth through tool transformation. We conclude the paper with implications for teacher education to better understand the role of AR in teachers’ agency development and professionalism.
Ali Delavar,
Volume 1, Issue 1 (3-1990)
Abstract
-
Ali Delavar,
Volume 2, Issue 3 (3-1991)
Abstract
-
Ali Delavar,
Volume 6, Issue 1 (3-1999)
Abstract
-
Volume 6, Issue 2 (Summer 2022)
Abstract
Research subject: In situ synthesis of nanoparticles due to greater impact on production mechanisms (such as reducing oil viscosity), uniform distribution of nanoparticles in reservoir fluids, no reduction in formation permeability due to no injection of nanofluids into the reservoir and also economic efficiency is more importance than other nanoparticle synthesis methods which are used in enhanced oil recovery (EOR) processes.
Research approach: In this study, the effect of in-situ synthesized of cerium oxide (CeO2) nanoparticles at low temperature on the oil recovery factor was investigated. For this purpose, water was considered as the based fluid for dispersion of synthesized nanoparticles. Also, in order to study the effect of nanoparticles concentration in the base fluid on the final oil recovery factor, several nanofluids were prepared at different concentrations of 0.01, 0.1, 0.25 and 0.5 wt.%. Finally, the prepared nanofluids were injected at the injection rate of 0.07 ml/h up to 1 PV into the micromodel and the amount of produced oil and the movement of the injected fluid in the porous medium were analyzed.
Main results: The results showed that the synthesized CeO2 nanoparticles in this study have appropriate performance to improve the oil recovery factor. The presence of small amounts of these nanoparticles (concentration of 0.01 wt. %), causes a significant increment in oil recovery factor (about 7%) compared to water injection alone. Also, the oil extraction coefficient increased by increasing the concentration of nanoparticles in the base fluid. So that for nanofluids with concentrations of 0.01, 0.1, 0.25 and 0.5 wt.%, the oil recovery factor were 25%, 38%, 43% and 45%, respectively. However, by increasing the concentration of nanoparticles in the base fluid, from an optimal amount onwards, the probability of particle deposition in the micromodel increased, the effect of nanoparticles on changing the hydrodynamic properties of the injected fluid and oil production mechanisms decreased.
Volume 7, Issue 4 (Fall 2018)
Abstract
The use of environmentally friendly methods is one of the new approaches in combating pathogens in aquaculture systems. The purpose of this research was the possibility evaluation of indirect use of Ag-NPs-coated porous ceramic in water filtration of culture system of shrimp post-larvae to control Vibrio harveyi. In this study, Ag-NPs-coated filters were characterized by various analytical techniques such as FTIR, XRD, ICP, and SEM. In this study, the antibacterial activity of Ag-NPs-coated on porous ceramic against mentioned bacteria via in vitro experiments Zone of inhibition test and Test tub test were determined. Then porous ceramic filter media used for water treatment. Therefore, the performance of the Ag-NPs-coated on porous ceramics in removing pathogenic bacteria was studied in two phases: In the first phase, V. harveyi was inoculated to the water and efficacy of filters of inhibition of bacteria was evaluated via total count of bacteria in the test water; in the second phase, the performance of the Ag-NPs-coated on porous ceramic was tested in the presence of shrimp larvae and efficacy of filters in inhibition of bacteria was evaluated via total count of bacteria, mortality rate, clinical signs, and also hepatopancreas and muscle culture. Based on the results, the highest zone of inhibition obtained in presence of Ag-NPs-coated porous ceramic modified by an aminosilane coupling agent, 3-Amino-Propyl-Triethoxysilane (APTES; the samples were immersed in the silver colloidal solution for 24h). The results of the flow test showed the highest bacteria removal efficiency from water with complete removal of the targeted pathogen. In the second phase, the results indicated a significant difference in decreasing of water bacteria, shrimp mortality and disease symptoms in treatment containing silver compounds compare to controls. According to results, Ag-NPs-coated porous ceramic have a high bacteria removal efficiency for the disinfection of water of culture system of shrimp to control Vibrio harveyi.
Volume 8, Issue 2 (Spring 2022)
Abstract
Backgrounds: Candida albicans (C. albicans) as a fungal pathogen is part of the normal flora of the human body, which could cause various infections in patients with defective immune systems. Nowadays, there is a need to design and synthesis new drug formulations to overcome drug resistance in this genus. Thymoquinone (TQ) is the main ingredient in Nigella sativa, which has considerable antifungal properties. The aim of this study was to investigate the inhibitory effects of thymoquinone-zein nanoparticles (TQ-ZNPs) on C. albicans.
Materials & Methods: In the current study, TQ was encapsulated in zein (as a biodegradable carrier) and polyethylene glycol (PEG). The antifungal activity of TQ-ZNPs against C. albicans (ATCC 10231; standard strain) and their inhibitory effects on biofilm formation were examined using standardized broth microdilution and MTT assays, respectively. The total oxidant status (TOS) of C. albicans was assessed using colorimetric method, and the toxic effect of nanoparticles on peripheral blood mononuclear cells (PBMCs) was evaluated by MTT assay.
Findings: The minimum inhibitory concentration (MIC) of TQ-ZNPs was significantly reduced compared to that of free TQ. MIC values of TQ-ZNPs and free TQ were determined to be 7.4 and 50 µg/mL, respectively. Biofilm formation was inhibited, and oxidant production by fungal cells was increased. The findings of this study showed that TQ-ZNPs had no toxic effect on PBMCs.
Conclusion: This study results revealed that the synthesized nanoparticles had a good antifungal activity without any toxicity. The results demonstrated the superior efficiency of TQ-ZNPs over free TQ. Hence, this structure could be used to load hydrophobic drugs. However, more studies are needed to evaluate the beneficial properties of TQ-ZNPs.
Volume 10, Issue 2 (Spring 2019)
Abstract
Effluent from dairy industry has a high amount of nutrients such as nitrate and phosphate. In this work nitrate and phosphate removal from treated dairy wastewater in the presence of organic load was investigated. For this purpose, 400ml of synthetic wastewater was inoculated with 2ml of seed culture of microalgae Chlorella salina. During the growth period, nitrate and phosphate concentration in synthetic wastewater was measured for 1, 3, 5 and 7 days with the standard method (APHA). Results showed that removal of nitrate and phosphate by the microalgae from synthetic wastewater was 100% and 95%, respectively. Also, maximum biomass production in 7 days of experiment was about 0.7g/L. These values showed that Chlorella Salina could be potential candidates by showing their intrinsic merit for removal of phosphate and nitrate from dairy wastewater and can be used in treated outlet refinement from the dairy treatment plant to be used before entering to the environment.
Volume 14, Issue 10 (1-2015)
Abstract
In present paper the Inamuro Model based on free energy approach of the Lattice Boltzmann Method (LBM) was used to simulate the motion of bubble and coalescence of two bubbles under buoyancy force. By combining the Tanaka and Inamuro models, three-dimensional model of Inamuro was used in two-dimension for decreasing the computational cost. Firstly it was ensured that the surface tension effect and Laplace low for two density ratio 50 and 1000 were properly implemented. Secondly in next step, effect of governing dimensionless numbers problem such as Etvos number and Morton number on Reynolds number and terminal shape of bubble were investigated. Different flow patterns in various dimensionless numbers were obtained and by changing the dimensionless number, terminal change of bubble’s shape was seen. Finally, motion of two bubbles and terminal shape of coalescence of two bubbles were studied in different dimensionless number, which shape of first bubble was same to single bubble, but it was seen that second bubble experienced various shapes due to its location in wake of first bubble and less difference pressure on two sides of this bubble.
Volume 17, Issue 3 (Fall 2013)
Abstract
Malaria is a vector born disease caused by protozoan parasites of the genus Plasmodium that causes 300-500 million new infections and 1 million deaths annually.Before any anti-malarial campaign in Iran, about 60% of the population were living in malaria endemic areas and 4 to 5 million of them had malaria infection each year. By starting of the anti-malaria campaign, the number of infections decreased so that the number of malaria infected in Iran was 3000 people in 2009, 0/65 of them lived in Sistan & Baluchistan province. In the present study, for spatial modeling of the Annual Parasite Incidence (API) of malaria in Sistan & Baluchistan province, we applied a Geographical Weighted Regression (GWR) model to predict API by there independent climatic factors. The results indicated that the most important climatic factor for explaining API in Sistan & Baluchistan is annual rainfall as spatial factor, which is more important in the southern parts of the study area such as Chabahar and Nikshar. Temperature and relative humidity are of the second and third prioriies, respectively. The importance of these two climatic factors is higher in northern portion of the province. This model explained only 0.48 of API spatial variation (R2=0.48). Therefore, the non-climatic factors such as socioeconomic and lifestyle and the neighborhood position of this province with Afghanistan and Pakistan should also be considered in epidemiological survey of malaria in Sistan & Baluchistan province.
Volume 17, Issue 3 (5-2017)
Abstract
Magnetic levitation systems are widely used in various industries. These kind of systems are usually open-loop unstable and are described by highly nonlinear differential equations which present additional difficulties in controlling these systems in the presence of disturbance and sensor noise. We consider the stabilization and the tracking problems of a magnetic levitation system. In this paper an adaptive fractional order Backstepping sliding mode control schemes is proposed. Backstepping algorithm is based on the Lyapunov theory. The proposed controller in this paper is designed by a combination of a Backstepping algorithm, sliding mode control and fractional calculus to make more degree of freedom and robustness. The stability of the closed loop system is investigated by using the Lyapunov stability theorem and the new extension of Lyapunov stability theorem for fractional order systems. Simulations are performed to confirm the theoretical results of the proposed controller for the magnetic levitation system. The proposed controller is able to reject the sensor noise and disturbance with a chattering free control law. Finally the simulation results of the proposed controller are compared with the adaptive fast terminal sliding mode control.
Volume 17, Issue 10 (1-2018)
Abstract
Energy saving, low robot mass to carried mass ratio, more ability to work in various environments, easier delivery of parts and lower production costs in flexible robots make these robots more attractive than rigid robots to many researchers and industries. But due to nonlinearities in flexible robot system and high vibration in operation points and also more sensitivity against external disturbances, control of these robots is more difficult and complex. In this paper a controller for a flexible link manipulator based on fractional calculus is practically implemented. At first the dynamic model of a single flexible-link robot is introduced. Then various controllers such as fuzzy control, PID control, and fractional order PID torque control are practically implemented on a single flexible-link robot made in laboratory, and then the performance of each controllers in decreasing of arm vibration in final desired point and tracking error reduction are investigated. Further, to compare the robustness of the designed controllers, a same constant disturbance is applied to all controllers and their performance are compared. Finally, the simulation results and experimental results show that the fractional order PID torque controller has the best results among the implemented controllers.
Volume 18, Issue 2 (6-2015)
Abstract
Objective: Cutaneous leishmaniasis is an endemic disease in certain areas of Iran. The use of pentavalent antimony compounds as first line treatment has been reported, however they are associated with limitations and adverse events. Hence, an attempt to find a new, effective compound has been under consideration. This study examines the effect of Achillea biebersteinii afan as, a native plant in Iran, against Leishmania major promastigote and amastigote growth under in vitro conditions.
Methods: This experimental study was performed at Tarbiat Modares University in 1392.We extracted the essential oil of the Achillea biebersteinii afan plant by steam distillation and analyzed it by gas chromatography mass spectrograph. Then, we evaluated the effect of different concentrations (10%, 15%, 25% and 50%) of the oil on the growth of the promastigotes stage of Leishmania and infected macrophages that contained amastigotes under in vitro conditions. Effectiveness of the oil on promastigotes and amastigotes was assessed by direct count and the MTT assay. In all tests, each of the wells that contained culture media and parasites without drug were considered the control group. Data analyses were conducted with ANOVA.
Result: The MTT results indicated significant differences among the number of parasites in the control and case groups treated with 10%, 15%, 25%, and 50% of the oil within 24, 48 and 72 hours after culture. The concentration of 50% of the oil killed 66% of the macrophages that contained amastigotes after 72 hours.
Conclusion: Achillea biebersteinii afan oil was effective in killing Leishmania major promastigotes and infected macrophages that contained amastigotes. We have proposed to study the extract in vivo for treatment of cutaneous leishmaniasis lesions.
Volume 22, Issue 1 (6-2018)
Abstract
This study is aimed to determine individual, psychological and organizational factors contribution in predicting Karaj municipality staff competence. Research methodology is descriptive and correlational where population included all staff in municipality in the 2014-2015. For research sample 300 employees were selected using stratified sampling. Designed standard questionnaire included: a) creativeness, b) Haplin & Kraft organizational climate competency assessment cite, d) Spritzer & Mishra psychological empowerment, e) Salovi & Mayer emotional intelligence & f) job motivation. Cronbach alpha coefficient for reliability testing was suitable. Regression results showed that personal characteristics couldn't predict competency significantly, and just psychological empowerment & emotional intelligence could predict employee competency significantly & organizational characteristics could predict competency significantly.
One of the scientific offers obtained from this research is that the managers of Karaj municipality can increase the level of efficiency of their organization by increasing the level of employee’s competency based on the contribution and influencing each individual, psychological and organizational factors. Results of this research can use for improving employees competency.
Volume 23, Issue 5 (Winter 2021)
Abstract
Objective : In the present study the effect of aqueous extract of
Fumaria which is a native Iranian herb on the promastigote and amasstigot under In vitro and In vivo condition.
Materials and Methods: The aqueous extract of the plant was prepared, then it was evaluated the effect of different concentration of aqueous extract under
In vitro condition on promastigotes, uninfected macrophages and macrophages infected with amastigotes by counting, MTT and Flow Cytometyry were evaluated. IC50 was calculated for promastigotes. Also, the effects of aqueous extracts of
Fumaria ointment on lesions caused by
Leishmani major in
BALB /
c mice were examined.
Results: The calculated IC50 of Funaria extract on promastigotes after 72 h was 304.17 µg/ml. The effects of
Fumaria extract showed effective limitation on lesion size. The survival rate for treated mice with Fumaria extract showed significant differences with control groups.
Conclusion: The results showed that
aqueous extract of Fumaria has antileishmanial effects in vitro and invivo condition. Also aqueous extract of Fumaria showed low toxicity against macrophages than pentavalent antimonials.
Volume 24, Issue 2 (6-2024)
Abstract
Dams are one of the best ways to store water in the long term. In general, it is important to increase the coefficient of water passage, more energy loss, and of course, to reduce scour downstream of dams and hydraulic structures and overflows. Weirs are part of hydraulic structures that allow more flow to pass over them during floods. Crump spillway also improves and protects the body of dams and spillway by passing excess flow during floods. Increasing the energy loss prevents the flow rate and scour or reduces the scour and prevents cracking and overturning of the crump weir. Many people have done valuable studies on the water transfer coefficient of crump weirs, but a review of previous research shows that few researchers have investigated the energy dissipation of crump weirs. Also, the energy dissipation in free flow and submerged states in Crump weirs has not been investigated. One of the conditions that can lead to an increase in energy loss is the presence of obstacles in the downstream slope of crump spillways. To better understand these cases, in this research, Crump spillways with different heights and slopes upstream and downstream were used. Also, the existence of the block (baffle) and the free and immersed states of the flow were investigated to estimate the energy losses. Experiments were carried out in a flume 10 meters long, 0.6 meters wide and 1.2 meters high. The flow is supplied by a pool tank and a pump. The flow is calmed down by flow relaxers and then reaches the overflow in 6 meters. To evaluate the effect of the slope and height of the spillway, three spillway models with a height of 0.15 meters and one spillway with a height of 0.2 meters and with different slopes upstream and downstream of the spillway were used. The flow rates used are 0.03, 0.035, 0.04, 0.045 and 0.05 cubic meters per second. By setting the appropriate engine speed for the pump, the flow rate entered the laboratory flume through the tank and the water depth was measured with the sensors installed on the top of the flume. The results showed that with the increase in the height of the overflows, the amount of energy loss decreases. The amount of energy loss in free flow mode with baffle is higher than the amount of energy loss in free flow mode without baffle. The amount of energy loss in submerged flow mode is lower than the amount of energy loss in free flow mode. As the downstream angle of the overflow decreases, the energy loss increases. By reducing the upstream angle of the overflow, energy loss is reduced. The amount of energy loss in free flow mode in type A, B, C and D spillways is 33.29, 33.83, 39.77 and 27.32% respectively. A general relationship was presented to calculate the amount of energy loss in crump weirs. In this relationship, there is a coefficient that is a function of free flow without baffle, submerged flow and free flow with baffle.
Volume 24, Issue 4 (10-2024)
Abstract
Labyrinth weirs are of the non-linear weirs whose discharge coefficient is higher than similar linear weirs. These weirs have a simple structure. They are mainly made in rectangular, trapezoidal, triangular and semicircular shapes. Investigating the amount of energy loss in these high-efficiency weirs has become very important for engineers in recent years. The experiments were carried out in a flume with a length of 10 meters, a width of 0.6 meters and a height of 0.8 meters. The flow is fed by a pump with an error of 0.01% by three surface tanks and after passing through the flow relaxers into the flume. In this research, four sinusoidal labyrinth weirs were used to check the amount of energy loss. The first spillway has a crown length of 1.3 meters, the second spillway has a crown length of 1.5 meters, the third spillway has a crown length of 1.55 meters, and the fourth spillway has a crown length of 1.6 meters. Also, the first and second weirs have a height of 0.15 meters and the width ratio of the inlet to the outlet is 6.86, and the third and fourth weirs have a height of 0.18 meters and the width ratio of the inlet to the outlet is 7.67. The flow depth in the upstream and downstream of the weir was taken by a point gauge with an error of 1 mm. Weirs are installed at a distance of 5.5 meters from the beginning of the channel. The downstream depth of the spillway was not artificially adjusted by the end valve of the laboratory flume. The weirs are made of wood and wood glue was used for their impermeability. The flow is transferred downstream over the sinusoidal edges of the weir like a curved slide or similar to peak weirs. Also, due to the sinusoidal nature of the weirs, the flow will be transferred downstream faster next to the walls. At the edge of the keys, a local vacuum is created. As the flow rate increases, the available air volume increases. At the downstream of the inlet and outlet keys, a vortex and rotation of the flow is formed, which increases in strength as the flow speed increases. The reason for the formation of vortices is the interference of the falling flow from each sinus. Due to the sinusoidal nature of the flow and the indentations and protrusions in the weir, the flow enters the downstream with a curve and the outflow from each sinus is mixed with the outflow from the other sinus. Also, at the beginning of the outlet keys, a small submerged area is formed, which increases in length and moves downstream as the flow rate increases. In front of the inlet keys, two relatively strong hydraulic jumps are formed, and after that the flow is transferred downstream more calmly. The results were that by increasing the flow rate or increasing the depth of the flow upstream of the weir, the energy loss decreased. Also, the amount of energy loss increases with the effective length of weirs. By increasing the ratio of the width of the input keys to the width of the weir output keys, the amount of energy loss increases. Also, by increasing the ratio of flow depth plus height, such as kinetic energy upstream of the weir to the height of the weir, the amount of energy loss decreases. The amount of energy loss is the highest in the fourth weir and the third weir, respectively. On average, with a 20% increase in the height of the weir, the amount of energy loss increases by 23.2%. Also, the average energy loss in type A, B, C, and D weirs is 42.3, 47.2, 57.9, and 58.6, respectively.
Volume 25, Issue 1 (4-2019)
Abstract
Academic engagement is crucial for the accomplishment of education and success in it, yet, with respect to existing challenges in the course of education, some students encounter with problems in this area. The main purpose of the present research is to promote academic engagement by using the stress inoculation training for students where academic stress and academic exhaustion play intermediary roles. For this purpose, we used a pretest-posttest design with a control group. 40 students were selected through a convenience sampling and randomly assigned to control and experimental groups. The experimental group was trained for 8 sessions of 120 minutes each. The groups were evaluated at three stages: pre-test, post-test, and follow-up. For data analysis, structural equation models with partial least squares approach were used in the form of the MIMIC model. The results showed that the stress inoculation training can firstly reduce academic exhaustion and academic stress significantly and in the second step can increase academic engagement indirectly and promote it. The follow-up model also confirmed these effects. In sum, the conceptual model of research explained 70% of academic engagement variance in the post-test phase as well as 38% in the follow-up phase which indicate the importance and effectiveness of Mindfulness Program.
Volume 30, Issue 1 (Spring 2022)
Abstract
Receiving the Qur’an as a literary text is one of the epistemological responses of scholars to this text in the twentieth century. This kind of reception has a long history in the Islamic heritage, especially in the studies of Qur’anic commentators and scholars, but there are fundamental differences between the literary reading of the Qur’an in the past and in the present. These differences arise from the methods used to analyze and study the literary text. If we look at the Qur’an as a literary text from the perspective of modern theories, we encounter with challenges because the literary text, under in this view, is considered an open and pluralistic text in terms of meaning, during its formation and reception. This article examines the challenges raised by receiving the Qur’an as a literary text in light of "Reception Theory". In this regard, it is observed that the principle of coherence provides us with a criterion for distinguishing interpretations close and far from the truth of the Qur’an and contributes to framing the reader's participation in the process of reading the Qur'an as a literary text from the perspective of modern theories.
