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Showing 636 results for Dynamic
Volume 0, Issue 0 (2-2024)
Abstract
The present case study had as its aim to uncover the diagnostic and instructional potential of dynamic assessment (DA) in the context of L2 writing during asynchronous computer-mediated communication (ACMC). More precisely, the study investigated the role of ACMC-based DA through e-mail in diagnosing and promoting low-proficiency L2 learners’ writing abilities in an Iranian EFL context. To this end, a case study design was adopted and three low-proficiency students of English as a Foreign Language (EFL) were selected to participate for a time span of ten weeks. The error analysis of learners’ performances in the pretest and posttest sessions led to the detection of a number of writing problems including the content, structural organization, grammatical accuracy, lexical appropriateness, and mechanics. A posterior examination of computer-mediated offline interactions led to the detection of a number of mediational strategies namely ask to revise, identify a problem area, specify the problem area, clarify the error kind, offer a choice and provide an explicit explanation as well as reciprocity patterns including unresponsive, growing autonomy and full autonomy which together helped diagnose the students' writing problems and trace their developmental trajectories. On implication side, it is argued that the ACMC-based DA serves as a strong diagnostic tool that makes a genuine understanding of L2 learners' writing abilities.
Keywords: dynamic assessment, sociocultural theory, asynchronous computer-mediated communication, writing
Volume 0, Issue 0 (8-2024)
Abstract
Aluminum nano-films are one of the functional elements that have various applications in different fields such as strengthening cement base materials, improving the performance and efficiency of concrete, and enhancing the mechanical and volumetric properties of clay. In this study, the mechanical responses of aluminum nano-film are investigated under uniaxial tensile and compressive tests using the molecular dynamics (MD) method. The initial configuration of the nano-film is constructed based on a 3D aluminum core—alumina shell model that provides a suitable description of surface oxidation in the nano-film. This model is useful to determine the influence of surface oxidation on the mechanical behavior of nan-film. Because of the accuracy and competency, the inter-atomic interactions are evaluated using the EAM+CTI potential, which is a hybrid potential consisting of two components, i.e., EAM and CTI potential, such that it can also take into account the electrostatic interactions between the atoms. After establishing the initial configuration, the energy minimization process is performed on the nano-film, and then its temperature and pressure are adapted to the environmental conditions through the relaxation process. The MD analysis is accomplished by the open-source LAMMPS software, and the visualization of outputs is performed by the open-source OVITO software. The periodic boundary condition is imposed on the lateral sides of the nano-film to eliminate the free surface effect of the atomistic analysis. The tensile and compressive tests are applied to the nano-film in accordance with the experimental tests, and the stress—strain curves are determined. The concept of Virial stress is employed to calculate the stress of the atomic model, which is equivalent to the conventional Cauchy stress in classical mechanics. In order to diminish the dynamic effects, deformation is incrementally applied to the nano-film, such that at each increment, a small strain is gently imposed, then the nano-film is relaxed under the deformed conditions, and finally the stress and strains are evaluated. The numerical simulations are verified by comparing them with experimental data, which demonstrates the acceptable accuracy of the obtained numerical results. The influence of various parameters such as the thickness and the percentages of oxide layers are investigated on the mechanical response and stress-strain curve of aluminum nano-film under the uniaxial tests. It is demonstrated that the thickness of the oxide layer significantly impacts the mechanical behavior, such that the hardness and energy absorption capacity of the nano-film is increased considerably by increasing the percentage of the oxide layer thickness. However, increasing the total thickness of the nano-film leads to a decrease in the Young’s modulus and elastic limit of the specimen. It is because of the decrease in the percentage of oxide layer thickness by increasing the total thickness of the nano-film. Point defects are one of the important imperfections in the crystal structures of atomic configuration that have a significant effect on the mechanical behavior of materials. In order to investigate the influence of point defects, different percentages of voids are generated by randomly omitting some atoms in the nano-film domain. The generated specimens are analyzed under the uniaxial tests, and their mechanical characteristics are evaluated. The numerical simulations demonstrate that the hardness of the nano-film is significantly reduced by increasing the point defects.
Volume 0, Issue 0 (8-2024)
Abstract
Masonry infills are generally assumed as non-structural elements in structural calculations and are not modeled. However, observations after past earthquakes have shown that masonry infills have significant effects on the seismic performance of structures and their seismic behavior should not be neglected. Additionally, the absence of masonry infills in the first story, which is common in structures for commercial and architectural reasons, has led to the occurrence of the soft story phenomenon in past earthquakes. The maximum interstory drift ratio (MD) is the most important criterion for assessing seismic damage and the occurrence of collapse in structures. In this study, the seismic performance of 3- and 9-story steel moment resisting frames (MRFs) with masonry infills was evaluated using a probabilistic framework considering the record-to-record variability. Two configurations were considered for the masonry infills including fully infilled and open ground story configurations. The seismic performance of the MRFs with these two configurations was compared to that of bare MRFs. The OpenSees software was employed for nonlinear modeling of the structures and masonry infills were modeled using single compression-only struts. The fundamental periods of structures with masonry infills significantly increase after the failure of the masonry infills. To evaluate these effects, Rayleigh damping was modeled using the conventional method and a modified method, which considers the severe elongation of fundamental period due the failure of infills, and the responses obtained from the two methods were compared. By performing incremental dynamic analyses using 78 far-field ground motion records, drift margin ratios (DMRs), drift fragility curves and mean annual frequencies of exceeding four MD levels of 0.7%, 2.5%, 5%, and 15% (λMD) were obtained for the structures. The MD levels of 0.7%, 2.5%, and 5% correspond to the performance levels of immediate occupancy, life safety, and collapse prevention, respectively. The MD level of 15% corresponds to the seismic collapse of the structures. The results indicate that the presence of masonry infills improves the drift performance of the MRFs with the fully infilled configuration. However, since the masonry infills experience failure at higher drift levels, their effectiveness decreases at these drift levels. Furthermore, the absence of masonry infills in the first story leads to the soft story phenomenon at lower drift levels, and therefore, the performance of the structures with the open ground story configuration is worse than that with the fully infilled configuration. It should be mentioned that at higher drift levels, due to the failure of masonry infills, the structures with the two configurations for infills have almost the same performance and close to the performance of the bare MRFs. The amplification of the soft story phenomenon in the 9-story structure causes the performance of the structure with the open ground story configuration given some drift levels to be even worse than that of the bare structure. For example, by using the modified damping method for the 3-story structure with the fully infilled configuration, the masonry infills reduce the λMD value given MD = 0.7% by 43%, but the reduction in the λMD given MD = 15% is 19%. Based on the results obtained, the conventional Rayleigh damping method in the technical literature underestimates the responses.
Volume 0, Issue 0 (8-2024)
Abstract
Horizontally curved bridges have been observed to suffer severe structural damage during past earthquakes so determining the seismic performance of curved bridges is crucial due to the complex dynamic behavior of these structures because of their irregular geometry and non uniform mass and stiffness distributions. Analyzing and plotting the capacity curve of these structures can be costly and time-consuming. As a result, many efforts have been made to simplify the structural models of these bridges and reduce the computational workload required for their analysis. This article presents a straightforward method to convert the multi-degree-of-freedom system of these structures into an equivalent single-degree-of-freedom system, ensuring that the capacity curve of the equivalent structure closely matches that of the original structure with minimal error. In this study, the OpenSees program was used to extract the stiffness and mass matrices of a curved bridge structure. These matrices were then condensed into one-by-one matrices for mass and stiffness using dynamic condensation equations. The characteristics of these matrices were applied to a single-degree-of-freedom stick model. In this model, the obtained mass is placed at the top of a stiff rod (stick), which is connected to the ground by a spring (zero-length element) with the equivalent stiffness obtained. A nonlinear static pushover analysis of the bridge structure was performed to obtain the capacity curve. An equivalent bilinear curve was then drawn, and the yield shear force and yield displacement were determined. The nonlinear behavior of the single-degree-of-freedom structure was modeled using the Steel02 material available in the OpenSees library by zero length element utilizing the yield shear force and yield displacement magnitudes of the curved bridge. The capacity curve of the stick model, which has a single degree of freedom, showed an error percentage of 7% compared to the bridge's capacity curve. This indicates acceptable compliance with the capacity curve of the main structure, making the stick model a viable alternative for repeated analysis of the curved bridge structure. This study also included a sensitivity analysis to investigate the effects of increasing the curvature radius and decreasing the curvature angle of the bridge on its capacity and effective mass. Due to the dynamic condensation of the curved bridge structure, the influence of all degrees of freedom was considered in the stiffness and mass matrices, unlike methods that rely solely on the first vibration mode for dynamic condensation. Comparing the capacity curve of each structure with that of an equivalent single-degree-of-freedom system revealed that the structure's capacity increases with a larger curvature radius. In contrast, the lowest capacity was observed in the straight bridge scenario. Additionally, modal analysis of the studied models showed that increasing the bridge's curvature radius leads to a longer structural period, while a decreasing curvature angle has a similar effect. However, the period of the straight bridge was longer than all the other models. Furthermore, as the curvature radius increased, the mass contribution percentage of the first mode in the translational x-direction decreased, whereas the translational mass contribution percentage in the y-direction and the rotational mass contribution around the z-axis increased.
Volume 0, Issue 0 (8-2024)
Abstract
Despite the particular importance of the subject of soil-structure interaction, unfortunately, this issue has received little attention from engineers, and seismic codes have not given much recommendation to consider its effects. Seismic wave frequencies vary continuously, and the stiffness of springs and damping of dampers connected to structural supports also vary with the loading frequency. To simplify time-domain numerical analysis, a constant target frequency can be used to keep stiffness and damping values constant. In the substructure method proposed in this study, the optimal target frequency is the one that yields results that most closely match those of a more accurate nonlinear 3D model analyzed using a direct method. A common simplification is to ignore the foundation’s non-linear response, justified by design requirements to prevent permanent deformation and the complexity of frequency-dependent soil behavior. Though not fully precise, this approach (considering soil heterogeneity and optimal target frequency) offers a forward-looking analysis and a basis for future nonlinear studies. This study presents a three-dimensional (3D) numerical model for analyzing the seismic response of soil-foundation-structure systems embedded in granular soil (with different relative densities) considering the effects of soil heterogeneity (With varying shear modulus with depth and compatible with the practical HSsmall model). The model is capable of accounting for the effects of loading frequency along with the radiation damping of the soil system and can integrate with the widely-used substructuring method considering an optimal target frequency. After verifying the proposed model, the dynamic equilibrium equations of the substructuring system were solved in the time domain using Matlab software. The target frequency was determined using i) Case 1: the fundamental frequency of the soil (or the dominant frequency of the excitations), ii) Case 2: the fundamental frequency of the structural system, iii) Case 3: the fundamental frequency of the soil-foundation-structure system; iv) Case 4: the fundamental frequency of structure with static stiffness and damping support (Case 4); and v) the fundamental frequency of fixed base structure and modified stiffness, and the results were compared together. A comparison of the impedance (dynamic stiffness and damping) of foundations situated on homogeneous and heterogeneous soil, as well as an investigation of the structural response in both cases, is another objective of this research. The analysis results demonstrated the accuracy of the proposed model and the acceptable calculation speed for estimating the dynamic response of structures located on heterogeneous soils under frequent operational earthquakes. The results also showed that with an increase in soil relative density, the seismic behavior of structures on homogeneous and heterogeneous granular soils converges. For instance, the response of the foundation on homogeneous soil bed with relative densities of 55%, 75%, and 95% is on average 23%, 19%, and 15% lower than that of heterogeneous soil, respectively. Additionally, for determining the target frequency, the use of frequency‐independent Kelvin–Voigt models (i.e., Cases 1-5) provides acceptable responses. According to the data presented in Table 4 and Figs. 9 and 10, the following conclusions can be drawn: 1) The soil's fundamental frequency (Case 1) yielded the least precise results. 2) While Case 3 offered the most favorable response, closely matching the direct method, determining the soil-structure system's fundamental frequency through complex integration in numerical software is often impractical. 3) Employing the target frequency in Case 2 produced more satisfactory results than Case 1. 4) Cases 4 and 5 generated nearly identical frequencies. Compared to Case 2, these cases enhanced response accuracy, bringing them closer to the best response (i.e., Case 3). Therefore, for practical applications, it is recommended to utilize the fundamental frequency from either Case 4 or Case 5 instead of the soil-structure system's fundamental frequency (Case 3) to establish the optimal target frequency.
Volume 0, Issue 0 (8-2024)
Abstract
Accurate analysis of bitumen behavior as a viscoelastic material and its natural phenomena such as aging are important issues in pavement engineering. Therefore, controlling the low and high temperature properties of bitumens is essential to prevent low temperature cracking and common high temperature distress in order to provide proper service throughout the pavement life. In this study, the aging phenomenon and its effects on the mechanical properties of bitumens were simulated using the Superpave method, namely the RTFOT method for short-term aging and the PAV method for long-term aging. In order to investigate the effect of repeated PAV cycles on the properties of bitumens, three types of bitumen with different penetration degrees of 40-50 (PG70-16), 60-70 (PG64-22) and 85-100 (PG58-28) were selected and three samples of each were subjected to one to three PAV aging times. The beam shear rheometer (BBR) test was performed at three temperatures from 0 to -12°C and the dynamic shear rheometer (DSR) at seven temperatures from 46 to 82°C. Based on the results obtained, the high temperature performance of the bitumens increased by a maximum of three grades and their low temperature performance increased by a maximum of two grades. In other words, the grading of the triple bitumens, after three times of PAV, became 82-4, 82-10, and 70-16, respectively. Also, the relationship between the high temperature performance properties of the aged bitumens and their chemical changes at different times of aging was investigated and their changes were examined to show the correlation between these properties. The results showed that the high temperature viscoelastic properties and the chemical aging index of the different bitumens had a strong linear relationship with a coefficient of determination (R2) of more than 0.9.
Volume 0, Issue 0 (12-2024)
Abstract
Aim and Introduction
There are many models and tools to communicate with the international economy and use its capacity to exploit for the benefit of the domestic economy. One of these famous models is the establishment of free zones and attracting international capital through these areas. According to the definition in the Kyoto Convention, a free economic zone is a part of the mainland where the exchange of goods is considered beyond the existing restrictions in the mainland and is not bound by the customs and tax laws of the mainland. Free zones have different economic regulations from other parts of the mainland. The differences can provide the basis for attracting capital, commercial prosperity, and economic growth. To grow and develop these areas, countries use various incentives such as legal, tax, customs, and financial incentives.
Methodology
The term general equilibrium in this method means that all the markets included in this structure must be in balance. In other words, the market settlement condition must be established. This means that in the general equilibrium model, all variables are assumed to be endogenous and non-constant, and this is contrary to the partial equilibrium structure, where the variables of other markets are assumed to be constant. This research analyzes the impact of customs exemption on imported goods in free zones in the form of the DSGE method with a neoclassical pproach. All the relationships necessary to explain the effectiveness of this incentive according to the theoretical foundations, the selected goals of the establishment of regions in Iran and their performance have been stated, and other relationships in other economic sectors have been considered to complete the model. The parameters of the model are also estimated according to the calibration method and using calculation software and econometric estimation. The performance of the model is evaluated by comparing the widths obtained from the simulation of the model and the torques of the real data. Finally, the simulation of the model can be seen by applying impulses.
Findings
In this study, the simulation of customs duty exemption impulses in free zones shows that applying impulses to increase import exemptions to free zones, leads to an increase in foreign direct investment, an increase in capital accumulation, an increase in exports of free zones, and finally, an increase in employment. As the export in free zones increases, the export of products from the mainland decreases.
Discussion and Conclusion
The results of applying the impulse effect of reducing import tariffs in free zones indicate that the intensity of the increase in the exemption of import tariffs for goods to free zones leads to an increase in foreign direct investment, an increase in the amount of investment, an increase in capital accumulation, an increase in the export of free zones and finally, the increased employment rate. In terms of export and domestic production, with the application of tariff reduction, imports in free zones will increase and exports from the mainland will decrease, and due to the weight of exports from the mainland compared to free zones, the total exports of the country will decrease
There are many models and tools to communicate with the international economy and use its capacity to exploit for the benefit of the domestic economy. One of these famous models is the establishment of free zones and attracting international capital through these areas. According to the definition in the Kyoto Convention, a free economic zone is a part of the mainland where the exchange of goods is considered beyond the existing restrictions in the mainland and is not bound by the customs and tax laws of the mainland. Free zones have different economic regulations from other parts of the mainland. The differences can provide the basis for attracting capital, commercial prosperity, and economic growth. To grow and develop these areas, countries use various incentives such as legal, tax, customs, and financial incentives.
Methodology
The term general equilibrium in this method means that all the markets included in this structure must be in balance. In other words, the market settlement condition must be established. This means that in the general equilibrium model, all variables are assumed to be endogenous and non-constant, and this is contrary to the partial equilibrium structure, where the variables of other markets are assumed to be constant. This research analyzes the impact of customs exemption on imported goods in free zones in the form of the DSGE method with a neoclassical pproach. All the relationships necessary to explain the effectiveness of this incentive according to the theoretical foundations, the selected goals of the establishment of regions in Iran and their performance have been stated, and other relationships in other economic sectors have been considered to complete the model. The parameters of the model are also estimated according to the calibration method and using calculation software and econometric estimation. The performance of the model is evaluated by comparing the widths obtained from the simulation of the model and the torques of the real data. Finally, the simulation of the model can be seen by applying impulses.
Findings
In this study, the simulation of customs duty exemption impulses in free zones shows that applying impulses to increase import exemptions to free zones, leads to an increase in foreign direct investment, an increase in capital accumulation, an increase in exports of free zones, and finally, an increase in employment. As the export in free zones increases, the export of products from the mainland decreases.
Discussion and Conclusion
The results of applying the impulse effect of reducing import tariffs in free zones indicate that the intensity of the increase in the exemption of import tariffs for goods to free zones leads to an increase in foreign direct investment, an increase in the amount of investment, an increase in capital accumulation, an increase in the export of free zones and finally, the increased employment rate. In terms of export and domestic production, with the application of tariff reduction, imports in free zones will increase and exports from the mainland will decrease, and due to the weight of exports from the mainland compared to free zones, the total exports of the country will decrease
Volume 0, Issue 0 (12-2024)
Abstract
Aim and Introduction
The financial sector has seen considerable growth in many post World War II western economies. The consequences of the Great Financial Crisis of 2007-2009 displayed how large the reach of the industry is, and how actions taken by a few important role players, can harm the general public. It is due to the consequences of the Great Financial Crisis that the notion of reforming the banking sector came about. The call for reform occurred in the 1940s as well, after the Great Crash. It was here that Full Reserve Banking (FRB), the broad term for the proposed banking reform and the subject of this dissertation, originated.
The Great Crash ended a period of expansion and growth in the USA in the 1920s where credit was easily available, and the money supply grew. The subsequent Great Depression was an economic event of unprecedented dimensions (Temin, 2000). The years 1929-1933 held a stock market crash, a banking crisis, and a collapse of commodity prices. Friedman and Schwartz (1963) contended that the primary propagation mechanism of the Depression was the contraction in the US money supply, together with banking panics. There were three banking crises in that short period, and it was the failure of two large banks, the Bank of United States and Caldwell and Company, that caused most of the problem. These banks had undergone rapid credit expansion in the 1920s and collapsed under the pressure of the recession (Temin, 2000: 307). A response to the recession was to say that the root cause was bad banking practice and that stricter regulations should be imposed to prevent future crises. Regulation was introduced in The Glass-Steagall Act (1933) however, a more severe suggestion was that bank deposits should be fully backed by bank reserves, Full Reserve Banking, an approach proposed in the Chicago Plan.
The Chicago Plan was proposed by Henry Simons, Irving Fisher and others, to prevent another crisis. It proposed requiring banks to hold 100 per cent reserves. This would simultaneously curb the possibility of reckless lending, and eliminate the risk of bank runs, thereby eliminating the possibility of another banking crisis.
Over the past years, the nominal capacity of the supply of bank facilities has increased significantly, and the main increase in bank assets has come from the increase in granting facilities. On the liabilities side of the banks' balance sheets, non-governmental sector deposits (due to paying high interest rates to depositors) during the year 2013 to 2022 has increased by 33.6% on average.
Statistical evidence shows that the real sector of the economy has not benefited much from the expansion of the banking network's balance sheet and the allocation of bank resources has not led to economic growth. On the other hand, it can be seen that the liquidity created by the banking system has not been absorbed by the real sector of the economy and its effects have been manifested in nominal variables in the form of price increases or turbulences in the currency market and other assets. The average growth of real GDP (without oil) during the years 2013 to 2022 was about 1.6 percent.
In general, it can be seen that due to the endogenous nature of money, the central bank has not had a significant success in controlling the growth of monetary aggregates through controlling the growth of the monetary base and its components (statistical evidence in recent decades confirms this); So that the credibility of the central bank's monetary policies has been challenged and the economy has been exposed to continuous threats of inflation and monetary and financial instabilities.
Methodology
This study will employ several techniques for gathering data, including a library type, a documentary branch, and the use of databases, such as those of the Central Bank of the Islamic Republic of Iran and the World Bank. Based on the characteristics of the Iranian economy under fractional & full reserve banking, a random dynamic general equilibrium model was developed for the period 1991-2021. Typical econometric methods are also used to evaluate the hypotheses. This has enabled assessing the effects of the exchange rate shock under two scenarios. It should be noted that the models were estimated in the dynare program space under MATLAB software.
Findings
The exchange rate shock has a negative effect on the consumption of the private sector at real prices, probably due to an increase in import prices. This has led to a decrease in the import of goods. Since imports form a part of the consumption for the private sector, therefore, the consumption by this sector decreases by about 0.5 percent. The Exchange rate shock has had a positive effect on the net foreign exchange reserves of the central bank. The growth rate of the monetary base is also affected by the currency shocks. With the increase in the exchange rate, although the central bank first reacts to the inflationary conditions resulting from the currency shocks through the currency reaction function and reduces the base monetary growth rate, but this situation is not very durable and finally the monetary base growth rate will increase by about 0.4 percent.
If these resources enter the banking system, due to the 100 percent reserve, it has led to the crediting of the banks, and as a result, inflation and final costs have decreased. But in fractional reserve banking, banks create money by attracting deposits, which in turn creates money by them. As a result of this jump, inflation and the final cost will increase.
The exchange rate shock also increases inflation because with the increase in the nominal growth rate of the exchange rate, the marginal cost of each import unit increases and finally the country's inflation increases by 0.7 percent.
Discussion and Conclusion
The purpose of this research is to investigate the effects of exchange rate impulse on the macroeconomic variables of Iran's economy in the conditions of partial and full reserve banking. To achieve this goal, a new Keynesian stochastic dynamic general equilibrium model was designed considering fractional and full reserve banking system (FRB). The realities of the Iranian economy are considered, and then the effects of exchange rate shocks under two types of banking are investigated. After determining the input values of the model and estimating the parameters using the seasonal data of Iran's economy during the period of 1991-2022 using the Bayesian estimation method, the results obtained from the simulation of the model variables indicate the validity of the model in describing the fluctuations of the Iranian economy. The results of the model indicate that, as a result of the exchange rate shock, the growth rate of the monetary base and consequently the amount of money is affected. Under full reserve banking, due to the full reserve of deposits, this has led to a lower increase in inflation and final cost. However, in partial reserve banking, due to the less control of the banking system, despite having two tools to control the growth of the monetary base and the nominal exchange rate, it will create higher fluctuations in the inflation rate and other macroeconomic variables. In other words, the study model has been slightly different from the basic model in the face of the currency impulse, both in terms of the amplitude and the length of the fluctuation
The financial sector has seen considerable growth in many post World War II western economies. The consequences of the Great Financial Crisis of 2007-2009 displayed how large the reach of the industry is, and how actions taken by a few important role players, can harm the general public. It is due to the consequences of the Great Financial Crisis that the notion of reforming the banking sector came about. The call for reform occurred in the 1940s as well, after the Great Crash. It was here that Full Reserve Banking (FRB), the broad term for the proposed banking reform and the subject of this dissertation, originated.
The Great Crash ended a period of expansion and growth in the USA in the 1920s where credit was easily available, and the money supply grew. The subsequent Great Depression was an economic event of unprecedented dimensions (Temin, 2000). The years 1929-1933 held a stock market crash, a banking crisis, and a collapse of commodity prices. Friedman and Schwartz (1963) contended that the primary propagation mechanism of the Depression was the contraction in the US money supply, together with banking panics. There were three banking crises in that short period, and it was the failure of two large banks, the Bank of United States and Caldwell and Company, that caused most of the problem. These banks had undergone rapid credit expansion in the 1920s and collapsed under the pressure of the recession (Temin, 2000: 307). A response to the recession was to say that the root cause was bad banking practice and that stricter regulations should be imposed to prevent future crises. Regulation was introduced in The Glass-Steagall Act (1933) however, a more severe suggestion was that bank deposits should be fully backed by bank reserves, Full Reserve Banking, an approach proposed in the Chicago Plan.
The Chicago Plan was proposed by Henry Simons, Irving Fisher and others, to prevent another crisis. It proposed requiring banks to hold 100 per cent reserves. This would simultaneously curb the possibility of reckless lending, and eliminate the risk of bank runs, thereby eliminating the possibility of another banking crisis.
Over the past years, the nominal capacity of the supply of bank facilities has increased significantly, and the main increase in bank assets has come from the increase in granting facilities. On the liabilities side of the banks' balance sheets, non-governmental sector deposits (due to paying high interest rates to depositors) during the year 2013 to 2022 has increased by 33.6% on average.
Statistical evidence shows that the real sector of the economy has not benefited much from the expansion of the banking network's balance sheet and the allocation of bank resources has not led to economic growth. On the other hand, it can be seen that the liquidity created by the banking system has not been absorbed by the real sector of the economy and its effects have been manifested in nominal variables in the form of price increases or turbulences in the currency market and other assets. The average growth of real GDP (without oil) during the years 2013 to 2022 was about 1.6 percent.
In general, it can be seen that due to the endogenous nature of money, the central bank has not had a significant success in controlling the growth of monetary aggregates through controlling the growth of the monetary base and its components (statistical evidence in recent decades confirms this); So that the credibility of the central bank's monetary policies has been challenged and the economy has been exposed to continuous threats of inflation and monetary and financial instabilities.
Methodology
This study will employ several techniques for gathering data, including a library type, a documentary branch, and the use of databases, such as those of the Central Bank of the Islamic Republic of Iran and the World Bank. Based on the characteristics of the Iranian economy under fractional & full reserve banking, a random dynamic general equilibrium model was developed for the period 1991-2021. Typical econometric methods are also used to evaluate the hypotheses. This has enabled assessing the effects of the exchange rate shock under two scenarios. It should be noted that the models were estimated in the dynare program space under MATLAB software.
Findings
The exchange rate shock has a negative effect on the consumption of the private sector at real prices, probably due to an increase in import prices. This has led to a decrease in the import of goods. Since imports form a part of the consumption for the private sector, therefore, the consumption by this sector decreases by about 0.5 percent. The Exchange rate shock has had a positive effect on the net foreign exchange reserves of the central bank. The growth rate of the monetary base is also affected by the currency shocks. With the increase in the exchange rate, although the central bank first reacts to the inflationary conditions resulting from the currency shocks through the currency reaction function and reduces the base monetary growth rate, but this situation is not very durable and finally the monetary base growth rate will increase by about 0.4 percent.
If these resources enter the banking system, due to the 100 percent reserve, it has led to the crediting of the banks, and as a result, inflation and final costs have decreased. But in fractional reserve banking, banks create money by attracting deposits, which in turn creates money by them. As a result of this jump, inflation and the final cost will increase.
The exchange rate shock also increases inflation because with the increase in the nominal growth rate of the exchange rate, the marginal cost of each import unit increases and finally the country's inflation increases by 0.7 percent.
Discussion and Conclusion
The purpose of this research is to investigate the effects of exchange rate impulse on the macroeconomic variables of Iran's economy in the conditions of partial and full reserve banking. To achieve this goal, a new Keynesian stochastic dynamic general equilibrium model was designed considering fractional and full reserve banking system (FRB). The realities of the Iranian economy are considered, and then the effects of exchange rate shocks under two types of banking are investigated. After determining the input values of the model and estimating the parameters using the seasonal data of Iran's economy during the period of 1991-2022 using the Bayesian estimation method, the results obtained from the simulation of the model variables indicate the validity of the model in describing the fluctuations of the Iranian economy. The results of the model indicate that, as a result of the exchange rate shock, the growth rate of the monetary base and consequently the amount of money is affected. Under full reserve banking, due to the full reserve of deposits, this has led to a lower increase in inflation and final cost. However, in partial reserve banking, due to the less control of the banking system, despite having two tools to control the growth of the monetary base and the nominal exchange rate, it will create higher fluctuations in the inflation rate and other macroeconomic variables. In other words, the study model has been slightly different from the basic model in the face of the currency impulse, both in terms of the amplitude and the length of the fluctuation
Volume 0, Issue 2 (8-2011)
Abstract
We measured the impacts of coastal modification on beach erosion and beach retreat conditions, selecting the Miankaleh Region as an example of a complex high-pressure free zone with high levels of engineering and tourism activity. Nine sampling transects, stretching from the shoreline to a 10 meter depth, were defined and 36 sediment samples were collected from the sea bed at depths of 1, 3, 5, and 10 m. After conducting laboratory tests, data were analyzed in terms of sediment dynamic parameters such as grain size, sediment size distribution, mean, median, skewness, kurtosis, standard deviation, and mineral composition. Beach structure and morphodynamic conditions were assessed in the Miankaleh region, by means of satellite image interpretation and field surveys. Results show that from 1978 until the present the average rate of beach retreat rapidly increased due to sea level rise and coastal constructions that have resulted in a progressive increase in sea level height in this region. Erosion vulnerability hazards have also increased in the eastern part of the study area and deposition processes have developed in the western Amirabad region.
Volume 1, Issue 1 (12-2017)
Abstract
The adsorption of polymeric systems onto reservoir rock through altering the wettability of rock surface improves oil recovery and reduces the unwanted water production. . In this study, the adsorption behavior of dilute polymeric systems based on sulfonated polyacrylamide on the glass particles surfaces (representative of sandstone reservoirs) was investigated and the effect of this phenomenon on changing their surface properties was examined. Results show that crosslinked polymeric samples have lower adsorption on glassy surface comparing with uncrosslinked sulfonated polyacrylamide solution. Furthermore, the contact angle tests results showed that crosslinked samples change the surface property of glass particle less than sulfonated polyacrylamide solution. In addition the Langmuir isotherm model fitted the isotherm data better than the Freundlich model for these dilute polymeric systems. Furthermore, study of the thermodynamic of adsorption showed that their adsorption behavior on glassy surfaces is a spontaneous and exothermic process.
Volume 1, Issue 1 (3-2023)
Abstract
Low Intensity Magnetic Separators (LIMS) are widely used in research and industry. The design of this separator is based on drum rotation inside a tank media, so that a permanent magnets placing inside the drum as an angle form, produces a magnetic field. In this study, the behavior of magnetic and none-magnetic particles of a pulp, flowing through a magnetic field in the wet LIMS, was simulated and validated by experimental results. The magnetic field variables were calculated in an FEM based simulator (COMSOL Multiphysics); while particles’ tracking was done applying CFD numerical method, enhanced by discrete phase model (DPM). The difference between the results of the simulation and the magnetic separation experimental test (recovery of magnetic particles in the concentrate product) was 16.4%. In order to quantify the results of the simulation, magnetic separation simulation was performed by changing two variables affecting the magnetic separation process (variables of particle size of the input pulp feed particles and solid percentage of input pulp) and corresponding experiments. Comparison of laboratory and simulation results showed that the trend of simulation results is consistent with laboratory results of the weight recovery (in both variables under study), so that the maximum simulation error is related to the size of 125 microns (16.5 %) and the lowest simulation error was in 180 microns (11.4 %). Also, the lowest simulation error in the weight recovery prediction was related to the pulp feed solid percentage of 15% (equivalent to 14%) and the highest simulation error was in 30% pulp feed solid percentage (16.9 %). This proposes that FEM-DPM-CFD coupling model, can be applied for simulation, optimization, design and construct
Volume 1, Issue 2 (3-2018)
Abstract
Nowadays, investigating and researching on energetic polymers in order to increase mechanical, thermodynamic, and detonational properties of them have been highly regarded. One of these energetic polymers is GAP. In this paper, molecular dynamics simulation has been used to compare the properties of GAP and GTP energetic polymers. GTP, in principle is the modified form of GAP, in which functional group of triazolium methyl nitrate has been added instead of azide. The mechanical properties of GAP is a challenging topic in the field of energetic materials. Due to the attributes of the 3 azoliom methyl nitrate ring, the mechanical and thermodynamic properties of GTP are expected to be higher than GAP. The results obtained by molecular dynamics simulation showed that GTP is a stable material and its mechanical properties such as Young, and shear modulus compared to GTP have been decreased 27% and 32% respectively, and bulk modulus, Poisson coefficient, and K/G ratio compared to GTPhave been increased 17%, 42%, and 71% respectively. It was also found that the detonation speed, detonation pressure, and oxygen balance of energetic polymer compared to GAP, have been increased 5%, 14%, and 21% respectively. As a result, usage of GTP will increase as a modified GAP material in applications such as clean and chlorine-free propellants for the solid propellant rockets and also safety systems of automobiles.
Volume 1, Issue 2 (9-2020)
Abstract
In addition to diagnostic measures in the early stages of the widespread disease of COVID-19, prevention of the presence of individuals in high-risk environments, along with the proper distribution of population and services, is also effective in controlling the spread of the disease. The epidemic model, is based on population and movement. The aim is to introduce hazardous maps at the outbreak of corona disease and to explain the framework for their preparation and application based on issues related to resident behaviors. This research has been done by the method of logical reasoning and by analytical study of the existing samples, the components that are effective in preparing these maps and updating them. To this end, after the typology of the maps, the results evaluation criteria were validated from the perspective of the outputs. According to the research results, the dynamics of human movement data are key to estimating spatial interactions in these maps; Because of the social distance, staying home, and closing down jobs, fundamental changes occur in individual and group movements. Using different sources of information can be provided, the platform for participation of different groups of users using mapping maps is provided with an active and inactive demographic approach and increased efficiency. The development of such maps is a collaboration between the fields of epidemiology, health, environmental psychology, and public planning and design, especially urban design, to ensure that integrated studies based on the dynamics of location-based behaviors greatly enhance the validity of the maps.
Volume 1, Issue 2 (7-2023)
Abstract
Hydrodynamic factors have been proved to effectively influence the high-performance heap leaching, hence this study evaluates them on column bioleaching of low grade uranium ore. Response surface methodology (RSM) was applied to predict the behavior of effective parameters particle size, irrigation rate, aeration rate and their interactions in the bioleaching process. Obtained results showed that the best model for the recovery of each metal was the quadratic model. The maximum values of uranium recovery at the optimum condition, (d80
Volume 1, Issue 4 (12-2012)
Abstract
Volume 1, Issue 4 (12-2012)
Abstract
Because of the strategic importance of avionic sector, being on technology edges, high spillovers to other sectors and high employment rate of this sector, aerospace policymakers have been focused on that during recent years and they have emphasized on the necessity of technological capability improvement in the avionic firms. Therefore, this article tries to answer this important question how to present an appropriate model for technological capability improvement in avionic firms. Hence, after establishment of a conceptual model, the survey and analysis of data extracted from 111 knowledge based firms of avionic sector were done. As well, direction and intensity of relations among latent variables were investigated using structural equation models. Finally, the model of technological capability improvement for avionic firms along with related consequences and suggestions were presented.
Volume 2, Issue 1 (5-2012)
Abstract
Abstract The present Research as” Design Business Agility Dynamic Model in manufacturing organization with dynamic systems approach”was performed . Initially the literature review discussed. The data gathered in this stage provided us with the possibility to present a conceptual framework for the study. Subsequently, through interviewing with experts, some indices for evaluating the variables in the model were identified. On the following stage, a questionnaire was developed. The questionnaire included 116 items, based on a 7-point Likert scale. After determining the validity and reliability of the results of the research revealed that agility capability, agility outcomes, and the internal supply chain of the organizations were less affected by environmental factors than agility enablers. The environmental drives by means of agility enablers, supply chain processes, agility capabilities and agility outcomes influence organizations Then, design Agility Dynamic Model and evaluated effect of changes in environmental drives and Policy of executives on organizational agility results After determining the validity and reliability of the results of the research revealed that agility capability, agility outcomes, and the internal supply chain of the organizations were less affected by environmental factors than agility enablers. The environmental drives by means of agility enablers, supply chain processes, agility capabilities and agility outcomes influence organizations Then, design Agility Dynamic Model and evaluated effect of changes in environmental drives and Policy of executives on organizational agility results
Volume 2, Issue 1 (5-2012)
Abstract
Abstract The present Research as” Design Business Agility Dynamic Model in manufacturing organization with dynamic systems approach”was performed . Initially the literature review discussed. The data gathered in this stage provided us with the possibility to present a conceptual framework for the study. Subsequently, through interviewing with experts, some indices for evaluating the variables in the model were identified. On the following stage, a questionnaire was developed. The questionnaire included 116 items, based on a 7-point Likert scale. After determining the validity and reliability of the results of the research revealed that agility capability, agility outcomes, and the internal supply chain of the organizations were less affected by environmental factors than agility enablers. The environmental drives by means of agility enablers, supply chain processes, agility capabilities and agility outcomes influence organizations Then, design Agility Dynamic Model and evaluated effect of changes in environmental drives and Policy of executives on organizational agility results The environmental drives by means of agility enablers, supply chain processes, agility capabilities and agility outcomes influence organizations Then, design Agility Dynamic Model and evaluated effect of changes in environmental drives and Policy of executives on organizational agility resultsوThen, design Agility Dynamic Model and evaluated effect of changes in environmental drives and Policy of executives on organizational agility results
Volume 2, Issue 2 (9-2018)
Abstract
In this study, the effects of drying temperature and mechanical pressure on the surface structure and dynamical properties of polyaniline (PAni) were studied. PAni was synthesized through the aniline polymerization process in the presence of ammonium persulfate in acidic medium and normal methyl-2-pyrrolidine solution. The obtained solution was dipped on a substrate of quartz glass. Atomic force microscopy (AFM) analysis based on nano-indentation tests were used to determine the values of hardness, Young’s modulus and Poisson’s ratio of the films. The results of the analysis of the scanning electron microscope demonstrated that the surface morphology of the film is changed from a fiber-to-interconnected cross-linked networkby increasing the drying temperature. The transmission electron microscope analysis showed that the diameter of the fibers on the surfaces dried at 318 K and 418 K was 18 and 30 nm, respectively. AFM results showed that the mean surface roughness of PAni film at 318 K without mechanical pressure was 63 nm, while for the film pressed at 5 MPa was less than 35 nm. Thermo-mechanical analysis showed that the glass transition temperature of the PAni film prepared without mechanical pressure and the film pressed at 5 MPa were 386 K and 378 K, respectively. Investigating the temperature dependence and applied pressure on the film surface in determining the viscoelastic properties of the PAni nanostructured film can provide readers with appropriate information about the storage and loss modulus of the film and the activation energy of the polymer layer during the thermal decomposition process.
Volume 2, Issue 4 (10-2000)
Abstract
This paper shows the role of the general dynamic model in empirical research of production technology in agriculture. The model is a first order autoregressive multivariate specification, first developed by Anderson and Blundell. This model is general enough to nest several simpler dynamic as well as static models within it. Therefore, it provides a framework for applying classical testing procedures and identifying the appropriate specification in the empirical econometric model of production. The usefulness of the general dynamic model is shown by estimating the production structure in the Iranian crop sector. The results indicate that the Iranian crop production is best characterized by a long-run static model derived from a non-homothetic translog specification which incorporates non-neutral technological change and allows for structural change after the Islamic Revolution of 1979.