Showing 6 results for Nikzad
Volume 4, Issue 2 (4-2012)
Abstract
Zoroastrians, Christians and Jews as "people of the Book" have lived in the Islamic lands and the Muslims, This coexistence has been subject to accept the conditions of the contract, namely “Ahlozummah” In the contract, provisions to create urban spaces and architecture by the minorities have been specified.
How and to what exlent contract provisions and obligations are reflected in the form of Iranian architecture and city spaces are, is the questions of this study. For this purpose, two historic Jewish neighborhood (Joyubareh) and the predominantly Christian (Julfa) were systematically studied. Selection of these neighborhoods was because they have been used continuously since the Safavid period and the architectural spaces have remained almost intact. Data analysis showed that the strength of jurists during the Safavidera, Iranian minorities living in the cities had no opportunity to implement the conditions stipulated in "Agreement of obligation".
Volume 10, Issue 3 (Fall 2020)
Abstract
Aims: Daylight has a great impact on the quality of indoor spaces, especially educational spaces. In educational spaces, visual comfort along with the use of daylight is of great importance. Therefore, the purpose of the present study is to evaluate the visual comfort in the classrooms.
Methods: Two indexes of illumination (lux) and Glare (DGP) were investigated to evaluate the visual comfort in 9 classrooms of 3 faculties from Polytechnic University of Shahrood. Attempts were made to examine at least one sample from each geographical direction. Cases were simulated in Grasshopper software via Honeybee plugin and then analyzed.
Findings: The evaluation of the Illumination (lux) index showed that only the class 2 in Mechanical Faculty was in accordance with Standards and in terms of DGP index, class 1 in Engineering Faculty was annoying at 10 and 14 o’clock in February. In the rest of the classes, the glare was due to reflective light and inappropriate lighting angle.
Conclusion: The results of the analysis showed that in the current situation, by making change in the spatial location of variables such as seats place and white board location relative to the position of windows, we can control the shading and better use of shades and light situations and can greatly improve the lighting quality of interior spaces. Also, the most important finding of the research is that the interior design of the space to create the connection between the light source and the layout and white board is not done by experts or is left to uninformed people.
Masood Aghakhani, Arash Nikzad,
Volume 15, Issue 7 (9-2015)
Abstract
One of the quality characteristics of welded joints in gas metal arc welding (GMAW) is weld height (WH). This paper highlights an experimental study carried out to develop a model using artificial neural network (ANN), to predict WH in GMAW in the presence of TiO2 nano-particles. For developing the model, the arc voltage, welding current, welding speed, percentage of Ar in Ar-CO2 mixture and thickness of TiO2 nano-particles were considered as input parameters and WBH as the response. A Doehlert design matrix was employed in the experiments to generate experimental data. The ANN model was developed and validated by conducting five extra runs. The remarkable outcome of this study is the mechanism of arc constriction due to interacting effects between welding input parameters and TiO2 nano-particles. Moreover, the results showed that increasing thickness of TiO2 nano-particles up to almost 0.9 mm increased weld height whereas, its further increase up to 1.0 mm, decreased weld height subsequently. In fact, this variation in weld height could be due to thermal dissociation of TiO2 nano-particles and CO2 releasing oxygen onto weld pool surface, which influenced its surface tension and consequently, changed direction of the Marangoni convection of fluid flow in weld pool and as a result, affected WH. For ANN technique, MSEtrain=0.0066, MSEvalidation=0.0063 and MSEtest=0.0093. Finally, it is to be concluded that ANN is an accurate technique for predicting weld height.
Volume 17, Issue 4 (1-2015)
Abstract
Objective: In order to improve the water solubility and bioavailability of curcumin in cancer therapy, we prepared and tested a novel waterborne cationic polyurethane (PU) as a nano-carrier for curcumin loading (CU-PU). We studied the effect of this prepared nano-drug on melanoma (F10B16) and fibroblasts cells (L929).
Methods: Morphology, size and cell internalization ability of the prepared nanoparticles were analyzed by zetasizer, SEM, AFM and fluorescent microscopy, respectively. We anticipated that curcumin was loaded in the hydrophobic core of the PU carrier. Next, the suitable dose and therapeutic effects of CU-PU for both skin cancer and normal cell lines were evaluated by the MTT assay and real-time PCR.
Results: The average diameters and polydispersity of the nanoparticles were 62.37 ± 1.7 nm and 0.080 ± 2.1 at 25 ̊C, respectively. The drug encapsulation efficiency was 87 ± 0.2%. The morphological analysis confirmed both a spherical shape and good dispersion without remarkable aggregation. The MTT assay results showed that the IC50 at 24 hours was 36.2 µM, whereas it was 25.4 µM at 48 hours. Real-time PCR results indicated that the CU-PU significantly decreased mRNA expressions of VEGF, Bcl-2, MMP-9 and COX-2 genes. An increase in mRNA expression of the BAX gene was also observed.
Conclusion: Our result provided acceptable evidence for cell proliferation inhibition and the apoptotic effect of CU-PU on skin cancer cells. There were no adverse effects detected for normal cells.
Volume 20, Issue 140 (October 2023)
Abstract
The bleaching process is important in the refining operation of edible oils. In this study, bleaching parameters were changed to evaluate the best condition for optimizing of bleaching in corn and sunflower oils. For this purpose, the effect of time (15, 25, 35, 45, and 55 min), temperature (80, 90, 100, 110, and 120 °C), and bleaching clay concentration (0.4, 0.6, 0.8, 1, and 1.2%) was evaluated using response surface methodology as statistical design in 5 levels by Central composite design with the aim of reducing the consumption of bleaching clay. The studied factors were including carotenoids, sterols, tocopherols, pigment and cations. After optimization, the best conditions for bleaching of corn and sunflower oils was different. For corn oil, the best conditions was time 39.59 min, temperature 103.61 °C, and bleaching clay concentration 1%, which meet 67% of our expectations. For sunflower oil with the aim of reducing the consumption of bleaching clay, the best conditions were time 37.49 min, temperature 97.53 °C and bleaching clay concentration 1%, which satisfied 70% of our expectations. The practical results did not show any significant differences with obtained theory values using response surface methodology and confirmed these results.
Volume 24, Issue 3 (Autumn 2024)
Abstract
Introduction
Balance of payment (BOP) shocks are one of the most important factors causing instability in economies that rely heavily on raw material export. Due to its dependence on oil revenues, the Iranian economy has been affected by balance of payment impulses in different eras, which have led to the instability of the macro-economy, especially the fluctuation of exchange rate, and sometimes occurrence of currency crisis. In the literature of public finance, there are several types of taxes on financial transactions, each of which has been introduced according to a specific purpose. Nevertheless, these taxes have common characteristics that are considered as basis for their selection and implementation at some point of time, especially during the periods of financial crises. These include curbing fluctuations of financial markets, collecting fair taxes and the possibility of reducing tax evasion compared to other taxes as the most important features. Tobin's original idea was a double tax on currency transactions, which is due when the currency is bought and sold. The mentioned tax has a bias towards long-term investment and leads to moving away from short-term speculation and ultimately creating economic stability. In general, this tax can lead to its spending by increasing investment returns and increasing economic stability.
Methodology
One of the presented instruments in the literature of open macroeconomics in order to control excessive exchange rate fluctuations, especially when the economy is faced with exogenous negative impulses such as international sanctions, is to control capital outflow through the Tobin tax in the exchange rate market. In this study, by presenting a DSGE model for an open economy and compatible with the conditions of the Iranian economy, it was tried to evaluate the role of Tobin Tax in stabilizing macroeconomic variables. The focus was especially on evaluating the exchange rate in response to the shocks of the balance of payment in the framework of the managed floating exchange rate system. The presented model in this paper is simulated using the Dynare program that runs in MATLAB software. Daynar is able to find steady-state values for variables of the model and calculates impulse response paths of variables in case of economic shocks. At this stage, the pattern is written in the form of a Dynare file, which should have 5 sections that include the introduction of all variables (including endogenous and exogenous variables and parameters), the equations in the model, the initial values of the variables, and the available impulses. If all the steps above are done correctly, the Dynare program simulates the model and produces the impulse response functions for the variables of model against the included impulses and a summary of the moments of the simulated variables. Hence, in this study, it will be tried to evaluate the role of Tobin Tax in controlling the balance of payments innovations in the framework of the management floating exchange rate system.
Results and Discussion
The results of the analyzed variables show that with the negative shock of oil export, the output also decreases. Due to the decrease in the foreign exchange reserves, the real exchange rate has increased initially. With a decrease in the output and an increase in the real exchange rate, inflation increases at first. With a decrease in the amount of the output, also the consumption will decrease. Finally, with a decrease in the amount of the oil exports, the balance of payment has also been disturbed. The results of the impulse response functions of the oil export as a balance of payment shock showed that the application of Tobin Tax has reduced the variance of the exchange rate resulting from balance of payment shocks, which is in accordance with the economic literature. The obtained results have also shown that, Tobin tax has reduced the deviations of inflation and the output that the welfare loss function have decreased.
Conclusion
Therefore, according to the resuls, the policymaker can use the Tobin tax as a more transparent and efficient policy tool than quotas in the exchange rate market, which lead to provide more efficiency exchange rate market in mid and long-run.
