جواد امامی

Foot and mouth disease (FMD) is the most significant livestock disease in the world and can cause great economic losses to the population of domestic ruminants. This study aims to investigate the economic impacts of FMD on dairy farms in West Azerbaijan province during the period of 2017-18.

Employing a questionnaire survey, this study covered all industrial dairy farms affected by the disease in eight units during the specified period. The results underwent descriptive analysis using Excel software version 2013 and SPSS version 18.

Absolute (in million Rials) and relative (percent) losses attributable to FMD were categorized as follows: mortality losses amounted to 2,170 million Rials (60.6%), distress sale of livestock reached 713 million Rials (19.9%), treatment incurred 288.65 million Rials (8.1%), short-term reduction of milk production accounted for 193.35 million Rials (5.4%), extra labor costs totaled 152.4 million Rials (4.3%), abortion amounted to 35 million Rials (1%), and sampling costs were 32 million Rials (0.9%). The total losses from FMD in dairy industrial farms were estimated at 3584.4 million Rials, equivalent to 38,758 dollars at the average exchange rate of one dollar to 92,487 Rials in 2018.

The substantial investment in dairy farms amplifies the economic impact of FMD, resulting in prolonged recovery periods and contributing to a decline in livestock and dairy production in the province and the country.

In complicated systems such as satellites, each subsystem's design can affect the design of the overall system. In the design procedure, the effect of each technology on the other components should be determined. Because of the increase in space trash, the propulsion subsystems are introduced to avoid collision in space. One of the methods to attain high altitude orbits is flight maneuvers using propulsion systems. Several types of propulsion systems are utilized in satellites. Resistojets can be employed as low-cost propulsion systems for satellites because they do not use complicated technologies. In the present research, a resistojet propulsion system is designed for a CubeSat for the mission of orbital altitude reduction. The propellant is selected considering all properties. The design of the nozzle and the heater is also introduced. The overall layout of the system is presented. In the end, an algorithm is proposed for electrical propulsion systems for a specified mission.

More than 85% of the West Azerbaijan ruminant population are kept in households in villages. Every year some of these livestock suffer severe economic losses due to Foot and Mouth Disease (FMD). The extent of these losses has not yet been investigated. One of the major direct and visible losses of FMD is the decline in milk yield, which has so far only been studied in a dairy herd in southern Iran. The present survey investigated the short-term reduction of milk production in households in villages using a questionnaire survey method. 111 cattle and 24 sheep and goats keeping  households that had reduced milk production due to FMD were studied. The mean milk production in cows from the first to fourth week after disease decreased by 42.3%, 50.7%, 44.8% and 35.5% respectively, and in sheep and goats, 49%, 41%, 36% and 26%, respectively. Mean loss of milk production per affected cow was 4,471,902 Rials, per affected household was 18,330,771 Rials and the total milk loss of affected cows of survey in disease period was 2,034,715,600 Rials. Mean milk loss per affected sheep and goats was 723,635.9 Rials, per affected households was 27,136,345.8 Rials and total milk loss of affected sheep and goats in disease period was 651,272,300 Rials, which was 43.3% of the total cow milk production and 38% of sheep and goats milk production in households, which is considered to be a serious loss.

This article provides a comprehensive critique and analysis of Ayatollah Beheshti's theory on the role of the people in governance and its impact on the electoral system of the Islamic Republic of Iran. Beheshti's theory, as one of the fundamental principles of the Iranian Constitution, emphasizes religious democracy and the active participation of the people in political decision-making. This article examines the historical and intellectual background of this theory and analyzes its strengths and weaknesses. Among its strengths are the integration of democratic principles with Islamic values and the institutionalization of public participation. However, challenges such as the conflict between religious democracy and the guardianship of the jurist (Velayat-e Faqih) and practical limitations in electoral processes are identified as key weaknesses. The article also assesses the extent to which Beheshti's theory aligns with the social and political realities of the Islamic Republic and offers suggestions for its development or revision. The findings indicate that, despite its significant strengths, Beheshti's theory requires review and reform to fully achieve the goals of religious democracy and adapt to contemporary conditions.

In order to achieve a thermal neutron beam for neutron radiography applications, a new neutron collimator has been designed, installed and characterized at Tehran Research Reactor (TRR). TRR is a 5 MW, open pool and light water coolant reactor with seven beam tubes. Neutron collimator that is an important part of neutron radiography system was installed in the six inch E beam tube. Collimator design was performed using MCNPX code. To improve the beam quality, polycrystalline bismuth as gamma filter and graphite as fast neutron moderator were used. Based on this design, the L/D of the system ranges between 150 to 250. The neutron flux at the image plane can be varied from 2.6x106 n cm-2 s-1 to 6.5x106 n cm-2 s-1. Preliminary measurements of the neutron beam were performed using foil activation method and TLD700 dosimeter for measuring neutron flux and gamma dose rate respectively after installation of the collimator in the beam tube. Results show that the measurements are in a good similarity with calculations and also the obtained beam has a good quality for neutron radiography applications and the parameters of this beam is comparable with other neutron radiography systems around the world.