Built on the northeast fringes of Shiraz, Darvazeh Qor'an (literally the gate of Holy Koran) was not only a gate to the city, but also included symbolic meanings related to religious beliefs. It retained its symbolic function even after the walls of Shiraz were demolished towards the end of Qajar dynasty. Recently the narrow road to Shiraz was widened and the gate now stands eccentrically alongside the road as a common landmark. This article tries to throw light on one of the most important principles in creation of Persian Islamic architecture, i.e. the spiritual symbolism .It is emphasized that this phenomenological dimension should never be compromised in developments that emphasize only the tangible physical dimension.

After compressing and increasing the pressure of natural gas in compress station, it has high exergy pressure. The pressure of natural gas is decreased in reduction station by regulators, but this issue can waste exergy. Since energy resources are restricted and its price is increasing in one hand, the exergy analysis method of thermodynamic issue is brought out with economic issues on the other hand, therefore the exergy analysis method is considered as significant issue. This article addresses exergy analysis with using the governing thermodynamic equations and considering natural gas deviation from ideal state and the exergy analysis of natural gas in reduction city gate station (the station No. 1 of Semnan is considered as a case study). The amount of exergy waste is calculated and guideline for its reduction is presented. In accordance with carried out calculations, on the average 198.7 MW of exergy is wasted in the Pressure Reduction Station No.1 located in Semnan in the year of 2009, we can prevent to waste the 231.98KW of exergy with regulating the appropriate temperature of heater when it is working and the studied station.

2Introduction: Reliability is always of particular importance in system design and planning; thus, improving reliability is among the approaches for achieving a safe system. Simulation methods are widely used in system reliability assessment. Therefore, this study aims to assess the reliability of the City Gate Gas Station (CGS) using Monte Carlo Simulation (MCS). Material and Methods: This descriptive and analytical study was conducted in one of the CGSs of North Khorasan Province in 2021. The CGS process was carefully examined and its block diagram was plotted. Then, failure time data of CGS equipment were collected over 11 years and time between failures of subsystems was calculated. The failure probability distribution function of subsystems was determined using Easy Fit software and Kolmogorov-Smirnov test. Moreover, subsystems’ reliability was estimated by MCS. Finally, station reliability was calculated considering the series-parallel structure of the CGS. Results: The results revealed that the failure probability density distribution function of CGS subsystems was based on gamma and normal functions. The reliabilities of filtration, heater, pressure reduction system, and odorize were calculated as 0.97, 0.987, 0.98, and 0.992 respectively, and their failure rates were 0.000003477, 0.0000014937, 0.0000023062, and 0.0000009169 failures per hour respectively. The station reliability was calculated as 0.93. Conclusion: The failure probability distribution function and reliability assessment of subsystems were determined by data modeling and MCS respectively. Filtration and pressure reduction systems had the highest failure rate and required a proper maintenance program.

In the present study, the main purpose is the qualitative study on garbage collection in Tehran city. It has been done by qualitative research method. Semi-structured interview and purposeful sampling techniques were used in data collection. To do this, 15 people were interviewed and the sample size in the present study was determined based on theoretical saturation. Thematic analysis was used to analyze the data. Theme analysis was performed at 4 levels of primary, main, central and core themes. A total of 184 initial themes were extracted from all interviews. In the main coding stage, the following 9 main themes were merged. Escape from poverty in the origin and the inevitable choice of inferiority, society's view to garbage collectors, and high stress, strengthening the cycle of academic reluctance and illiteracy, physical and mental torment, unknown horizon and confusion of the Khojies, legal ambiguity and customary definitions and contracts, complaints from relevant institutions, the entry of the mafia and the formation of rent and corruption. Finally, these themes fall into two categories of social harmfulness of recycling and institutional exclusion and illegallity of the status of garbage collectors in the second distrect in the form of the core theme of the structure of socially harmful and institutionally illegal, waste phenomenon explained..

City gate stations are installed at gas network entries to decrease pressure along gas transmission pipelines from 1000 psi to roughly 250 psi. Since Joul-Thomson constant of natural gas is positive, the aforementioned decrease in pressure also results in a decrease in the temperature, making the existing water vapor in the gas to condense or even to freeze during cold seasons. Hence, indirect heaters are employed to somewhat raise the gas temperature to eliminate the possibility of freezing. A major portion of the resulting heat from gas combustion is transferred to the environment through a smokestack. In the present study, the purpose is recovering this lost energy by modeling the smokestack and calculating the parameters of its passing smoke parameters. To this end, a thermoelectric generator was designed for installation on the smokestack in these stations. According to the findings, more than 400 kW of electrical power may be generated using 90 high-efficiency modules of type TEG1-241-1. 4-1. 2 installed on a smokestack of 3 spaces.

Today more than ever, we need high-speed circuits with low occupancy and low power as an alternative to CMOS circuits. Therefore, we proposed a new path to build nanoscale circuits such as Quantum-dot Cellular Automata (QCA). This technology is always prone to failure due to its very small size. Therefore, designers always try to design fault-tolerant gates and provide methods to increase the reliability of QCA. By adding redundant cells, the possibility of some defects such as cell omission and cell addition is somewhat reduced. However, in the face of defects such as stuck-at 0/1 faults, Clock fault and bridging fault. We can greatly increase the fault tolerance by appropriate placement and using fault tolerant gates with a suitable structure. In this paper, we design the XOR/XNOR gate with the approach of preventing stuck-at 0/1 fault, clock fault, and bridging fault using the first NNI gate tolerating cell addition fault.

Gate Induced Drain Leakage (GIDL) current is one of the main leakage current components in Silicon on Insulator (SOI) MOSFET structure and plays an important role in the data retention time of DRAM cells. GIDL can dominate the drain leakage current at zero bias and will limit the scalability of the structure for low power applications. In this paper we propose a novel technique for reducing GIDL and hence off-state current in the nanoscale single gate SOI MOSFET structure. The proposed structure employs asymmetric gate oxide thickness, which can reduce GIDL current, and hence Ioff current to about 98% in comparison with the symmetric gate oxide thickness structure, without sacrificing the driving current and losing gate control over the channel. This technique is very simple in the fabrication point of view in CMOS technology.