---

Oil is one of the significant factors in promoting economic activities. Oil provides a considerable part of the government's revenue sources. The price of oil has always been fluctuating over the years for various reasons including political, social, and economic developments in countries. Since the price of oil affects different sectors of economy including the agricultural sector through the government budget and the revenue sources of the government, this study investigated the effect of positive and negative fluctuations in OPEC oil prices on the value added of the agricultural sector during 1990-2019. The new GAS method was used for estimating the OPEC oil price fluctuations and the NARDL method was used for estimating the long-term relationships between positive and negative OPEC oil price fluctuations on the value added of the agricultural sector. In addition to OPEC oil price fluctuations, other independent variables such as the consumer price index, employment in the agricultural sector, and the degree of trade openness were examined in the model. Based on the obtained results, the positive and negative fluctuations of OPEC oil prices in the long term had a negative effect on the value added of the agricultural sector. Furthermore, the degree of trade openness had a positive effect on the value added of the agricultural sector in a long term. results indicate that oil income is one of the most important issues that decline value added of agriculture sector and government should control this negative relation to develop agriculture as a vital sector of economic.

---

     The Oriental hornet, Vespa orientalis L. (Hymenoptera: Vespidae) is one of the most important and serious enemies of honeybees. In this study, the annual population dynamics and daily activity rhythm of Oriental hornet were examined, based on the number of adults trapped in an apiary located in Ahvaz (southwest of Iran) during a period of two years (January 2021 to December 2022). Samplings were performed using the box traps available in the market. The bait used in the traps was fresh chicken liver, with the traps checked daily in four time periods. The results revealed that the first overwintering queens (gynes) emerged in March and two population peaks of newly emerged hornet workers occurred during the year, one in July and the other in October. In late November and early December, no adult hornet was trapped. The daily activity rhythm of adult hornets was observed mostly during 9 - 12, almost twice as much as in the afternoon period (12 - 15). The lowest activity was recorded in the evening period and night (6 pm - 9 am). During both years of sampling, the seasonal abundance of adult hornets displayed a significant positive correlation with air temperature and a significant negative correlation with relative humidity. By comparing the result of our findings with other studies performed in the same and different climate zones, it can be hoped to present effective methods to control the population of V. orientalis, especially in areas that have extensive beekeeping.

---

Rapid increase in housing price has been a national difficulty for the people and public officials in recent years in Iran. Therefore, the study of factors affecting increased housing prices is of great importance. In this paper, the effects of some key variables, including land price, construction cost, the volume of bank loans to housing sector, exchange rate, stock price index, the number of residential buildings and household income on the price of housing have been studied in Kermanshah. For analyzing the effects of above-mentioned variables on price of houses, an auto regressive distributed lag model has been estimated using quarterly data over the period 1991-2009. Additionally, the error correction model was estimated in order to evaluate the adjustment speed of dynamic model to the long-run one. The estimation results indicate that the macroeconomic variables are of high power in explaining the behavior of house price and its fluctuations.

---

Since various economic sectors, in particular housing sector, need to bank loans, the variations in lending behavior of banks due to changes in key economic variables may jeopardize the sound economic activities. In this study the lending behavior of Bank Maskan of Iran was modeled by a Vector Auto-regression (VAR) model during 1991-2011. The results of long run Vector Error Correction Model (VECM) indicated that the broad money supply, inflation rate and stock price fluctuations have indirect effects on lending behavior of Bank Maskan, however the effect of exchange rate variations is positive. In addition, the results of short run VECM showed that variations in the broad money supply have direct effects on lending behavior of Bank Maskan, but inflation rate, exchange rate and stock price fluctuations have no significant effects.

---

Accurate measurement of unsteady pressure fluctuations along a surface requires experimental set up with high spacing resolution and high frequency domain. Therefore, in recent decades extensive studies have been conducted on remote microphone approach. In this method, instead of using flash mounted sensors, they installed remotely and connected to the model surface through one or several continuously connected tubes. Surface pressure fluctuations will travel within the tubing in the form of sound waves and they will be measured when passing over the remote pressure sensor, mounted perpendicular to the tubing. In the present study, an analytical solution of sound waves propagation inside the rigid tubes is used for modelling of the remote microphone system and to investigate the effects of its parameters on dynamic response. In order to verify the accuracy of proposed modeling, the dynamic response of a typical remote microphone has been obtained through experimental calibration. Comparing the analytical and experimental results indicates high accuracy of the analytical modeling. Results show that changes in tubing diameter leads to occurrence of resonance and creating harmonics in two frequency regions. The amplitude of low-frequency harmonics depends on the length of the damping duct and decreases with increasing of its length. Instead, the amplitude and frequency of high-frequency harmonics depend on the length of the first tube and they decrease with the increase of first tube length. Also, Increase of the first and second tube lengths lead to an increase in phase of dynamic response of the remote microphone system.

---

Surface pressure fluctuations beneath turbulent boundary layer on a flat plate have complex physical behavior and due to its importance in acoustic noise generation, extensive studies have been devoted to predicting or measuring the surface pressure behavior. In the present study to investigate the surface pressure fluctuations under zero pressure gradient, a flat plate with a chord length of 580 mm has been used. All experiments were carried out in a subsonic wind tunnel and at three free-stream velocities: 10, 15 and 20 m/s. In order to measure unsteady pressure fluctuations, a condenser microphone is used as a pressure transducer. Moreover, various parameters of turbulent boundary layer are measured to provide the input variables of semi-empirical models. A single constant temperature hot-wire anemometer has been used for boundary layer measurement. Surface pressure spectra has been measured at various velocities and their collapse on a single curve by normalizing with different variables of turbulence boundary layer is studied. The results show that the best collapses in low and middle frequencies can be obtained by using mixed variables. However, in high frequency range the pressure spectra collapses when it is normalized by inner layer scales. Finally, after ensuring the accuracy of surface pressure spectra results, the efficiency of semi-empirical models for predicting turbulent boundary layer wall pressure spectra is evaluated. The results show the effectiveness of the Goody’s semi-empirical model for prediction of surface pressure spectra by using turbulent boundary layer parameters.

---

Today, the embankment dams are considered more prominent than concrete dams because of its formation and lower cost. According to the official site of the International Commission on Large Dams, embankment dams account for about 64 percent of the world's total dams. The results of the statistical analysis of the International Commission on Large Dams showed that the main cause of damage of half of the embankment dam is erosion that usually occurs during the first impounding of the dam reservoir. Therefore, the stability and leakage conditions of the embankment dam should always be examined. Moreover, the analysis showed that drying of the embankment dam due to drought and re-watering the reservoir is similar to the first dam impounding and therefore it is necessary to investigate it. One of the factors affecting the physical and mechanical properties of embankment dams is the effect of drying and wetting cycles of the core soil due to high fluctuations in reservoir water levels during prolonged dry periods and re-watering. In this study, the effects of frequent wetting and drying cycles of Doosti dam clay core were investigated. Investigation of the effect of frequent cycles of wetting and drying on compressive strength of soil showed that by applying drying and wetting cycles on specimens prepared from Doosti dam core borrow area, the compressive strength of specimens decreased. Increasing the number of wetting and drying cycles of the specimens increases the intensity of the compressive strength reduction of the specimens so that the greatest decrease in compressive strength occurred in the third cycle. Application of wetting and drying cycles on the specimens showed that application of such cycles reduced the amount of soil cohesion. The highest decrease in cohesion of the specimens occurred in the first three cycles and in the next four cycles, the intensity of cohesion parameter decreased. The cohesion of the specimens was reduced by 50% by applying six drying and wetting cycles. Results showed that with increasing number of drying – wetting cycles, there is no significant change in internal friction angle. Furthermore, the results of the hydraulic conductivity test showed that the application of six cycles of drying and wetting increased the hydraulic conductivity by 1.9 times. Furthermore, the characteristic curves obtained in this study showed different drying and wetting cycles, indicating that the percentage of volumetric water content in all cycles decreased due to increased suction. The soil-water characteristic curve also shifts downward with increasing number of wetting and drying cycles, decreasing soil water retention capacity and increasing the possibility of internal erosion and dam instability. Finally, Doosti dam numerical modeling was performed using GEOSTUDIO software in end of construction conditions and in two cases without drying and wetting cycle and with six drying and wetting cycles. The results obtained for numerical modeling in general were very consistent with Doosti dam instrument readings. Moreover, the results of the core settlement after the six drying and wetting cycles compared to the non-cycled state in numerical modeling showed a 38.3% increase in the dam core settlement.
 
 

---

Exchange rate is one of the most influential factors affecting Iran's macroeconomic variables. Exchange rate fluctuations in Iran have always been one of the major challenges for policymakers. On the other hand, many central banks today consider transparency as one of the main and vital priorities in achieving the effectiveness of monetary policy and communicating effectively with the people and being accountable. This transparency can affect macroeconomic expectations and the exchange rate. In this study, the effect of central bank transparency on exchange rate fluctuations is investigated using the ARDL method over the period 1981-2018. This study is based on analytical, applied and correlational research methods, which uses time-series econometric regression model. The transparency of the central bank, as independent variable, is measured by Dincer & Eichengreen index, and exchange rate fluctuations, as dependent variable, are constructed by GARCH method. The results show that the transparency of the central bank reduces exchange rate fluctuations in both short run and long run, and there is a long-term synergistic relationship between research variables.

---

Abstract The study area of this research line is the East coast of the Caspian Sea. The main objective of the study was to evaluate the shoreline past 59 years. To achieve this goal, in the Caspian Sea level fluctuations during the past 59 years were collected from available resources. And continue to monitor shoreline changes using satellite imagery landsat ETM 7 belonging to the years 1364,1370,1380,1390,1393 and 1334 aerial photographs and satellite images from 1389 Cartosat (IIRS -p5) was used. After extraction coastline coastline change the situation in the region was analyzed. The output maps showing the Caspian Sea level changes in time scale is short, so a greater role in the region's coastline change. Following the changes in the coastline, changes and displacement took place because of the heterogeneity of the morphology of the coastal area along the coast to study the impact of these changes has not been the same area. North Shore area due to the gentle slope toward the East Coast Miankaleh more sensitive to shocks is shown in blue. The study area of this research line is the East coast of the Caspian Sea. The main objective of the study was to evaluate the shoreline past 59 years. To achieve this goal, in the Caspian Sea level fluctuations during the past 59 years were collected from available resources. And continue to monitor shoreline changes using satellite imagery landsat ETM 7 belonging to the years