The Study of Surface Properties of Tokamak First Wall Using TiN Coated on Stainless Steel

Structural properties of the synthesized TiN thin film on 316L stainless steel (S.S.316L) were studied to determine its potential application as a protective layer for first wall of Tokamaks. For this purpose we deposited TiN on stainless steel 316L (TiN/S.S.316L) via DC magnetron sputtering method and annealing at 700 °C. Before and after exposure, samples were analyzed by using scanning electron microscopy (SEM), X-ray diffraction (XRD) and a spectrophotometer. The XRD analysis for studying crystalline structure of samples shows the position and intensity of XRD peaks has changed after exposing to 500 shots of Tokamak. It was found that the S.S.316L sample was severely damaged, its reflection dropped significantly but the SEM images show that plasma exposure has not created any cracks and lines on the surface of the TiN/S.S.316L sample and mass of dust particle has been assembled in some area of the sample.     

Performance Evaluation of Deteriorating Highway Bridges Located in High Seismic Areas

This paper studies the life-cycle performance and cost of reinforced concrete highway bridges subjected to earthquake ground motions while they are continuously exposed to the attack of chloride ions. The penetration of chloride ions into the concrete is simulated through a finite difference approach that takes into account all the parameters that can affect the corrosion process. From simulation results, the corrosion initiation time is predicted, and the extent of structural degradation is calculated over the entire life of the bridge. A group of detailed bridge models with various structural attributes are developed to evaluate the changes in the structural capacity and seismic response of corroded bridges. For the purpose of the probabilistic seismic risk assessment of bridges, the seismic fragility curves are generated and updated at regular time intervals. The time-dependent fragility parameters are employed to investigate the life-cycle cost of bridges by introducing a performance index that combines the effects of probable seismic events and chloride-induced corrosion. The proposed approach provides a multihazard framework that leads to more realistic performance and cost estimates.     

The 1968 Tehran master plan and the politics of planning development in Iran (1945–1979)

ABSTRACT

This paper traces the relationship between state development policies and planning Tehran’s urban development from 1945 until the 1979 Islamic Revolution. It shows how the geopolitical context of the Cold War, and the political agendas of multilateral and bilateral development agencies (i.e. the World Bank and the Ford Foundation), together with the specific circumstances of the national modernization of Iran, were decisive in shaping the Iranian planning administration and the emergence of a comprehensive master planning approach. Moreover, this study demonstrates the critical role of the Iranian technocratic elite and professional middle class in establishing planning institutions and advocating for a vision of progress and development. The focus here is on the formation of the ‘Plan Organization’ as the first modern planning institution in Iran, and the ways in which this institution played a key role in shaping Iranian expert culture and urban planning practices. By examining the links between national development policies and urban planning, this paper presents how comprehensive master planning emerged as the preferred model for the planning and development of Iranian cities. The focus here is on the design and implementation of Tehran’s 1968 Comprehensive Master Plan.     

On the distributed construction of a collision-free schedule in multi-hop packet radio networks

This paper introduces a protocol that distributively constructs a collision-free schedule for multi-hop packet radio networks in the presence of hidden terminals. As a preliminary step, each wireless station computes the schedule length after gathering information about the number of flows in its neighbourhood. Then, a combination of deterministic and random backoffs are used to reach a collision-free schedule. A deterministic backoff is used after successful transmissions and a random backoff is used otherwise. It is explained that the short acknowledgement control packets can easily result in channel time fragmentation and, to avoid this, the use of link layer delayed acknowledgements is advocated and implemented. The performance results show that a collision-free protocol easily outperforms a collision-prone protocol such as Aloha. The time that is required for the network to converge to a collision-free schedule is assessed by means of simulation.     

Local Insulin-Derived Amyloidosis Model Confronted with Silymarin: Histological Insights and Gene Expression of MMP,TNF-α, and IL-6

Amyloidosis is a heterogeneous group of protein deposition diseases associated with the presence of amyloid fibrils in tissues. Analogs of insulin that are used for treating diabetic patients (including regular insulin) can form amyloid fibrils, both in vitro and in vivo as reported in patients. The main purpose of this study was the induction of localized insulin-generated amyloidosis and the observation of silymarin effects on this process. In order to obtain amyloid structures, regular insulin was incubated at 37 °C for 24 h. Congo red absorbance and transmission electron microscopy images validated the formation of amyloid fibrils. Those fibrils were then injected subcutaneously into rats once per day for 6, 12 or 18 consecutive days in the presence or absence of silymarin, and caused development of firm waxy masses. These masses were excised and stained with Hematoxylin and Eosin, Congo red and Thioflavin S. Histological examination showed adipose cells and connective tissue in which amyloid deposition was visible. Amyloids decreased in the presence of silymarin, and the same effect was observed when silymarin was added to normal insulin and injected subsequently. Furthermore, plasma concentrations of MMP2, TNF-α, and IL-6 inflammatory factors were measured, and their gene expression was locally assessed in the masses by immunohistochemistry. All three factors increased in the amyloidosis state, while silymarin had an attenuating effect on their plasma levels and gene expression. In conclusion, we believe that silymarin could be effective in counteracting insulin-generated local amyloidosis.     

Modeling groundwater nitrate concentrations using spatial and non-spatial regression models in a semi-arid environment

Nitrate nitrogen (NO₃^--N) from agricultural activities and in industrial wastewater has become the main source of groundwater pollution, which has raised widespread concerns, particularly in arid and semi-arid river basins with little water that meets relevant standards. This study aimed to investigate the performance of spatial and non-spatial regression models in modeling nitrate pollution in a semi-intensive farming region of Iran. To perform the modeling of the groundwater's NO₃^--N concentration, both natural and anthropogenic factors affecting groundwater NO₃^--N were selected. The results of Moran's I test showed that groundwater nitrate concentration had a significant spatial dependence on the density of wells, distance from streams, total annual precipitation, and distance from roads in the study area. This study provided a way to estimate nitrate pollution using both natural and anthropogenic factors in arid and semi-arid areas where only a few factors are available. Spatial regression methods with spatial correlation structures are effective tools to support spatial decision-making in water pollution control.     

轴向和循环荷载组合下夹角对纤维复合材料包裹钢筋混凝土梁柱节点性能的影响

通过数字分析,研究轴向和循环荷载作用下夹角对采用碳纤维复合包裹的钢筋混凝土梁柱节点的剪力和延性的影响。对于梁柱节点,建立了三维非线性有限元模型并采用Marc．Mentat^TM 2001有限元分析软件进行模拟。采用已有文献中纤维增强复合材料包裹梁柱节点试验研究所提供的资料,对有限元模型的精度进行评估。用有限元方法分析不同夹角配置的碳纤维增强复合聚合物包裹加固的3个梁—柱节点的性能。分析结果显示：与水平轴成±45°,连续4层包裹纤维增强复合聚合物,对于提高轴向和循环荷载组合下梁—柱节点的剪力和延性,是最好的设计方案。     

A hybrid GA-simulation approach to improve JIT systems

This study presents a hybrid approach involving genetic algorithms (GAs) as an optimisation search technique and a simulation model, representing the dynamic behaviour of a system and its limitations, to improve an existing just-in-time (JIT) manufacturing system. To achieve the objective, first, the existing system is modelled and simulated (by considering the system's limitations and its dynamic behaviour). Second, the integrated simulation model is tested and validated by analysis of variance. Third, the hybrid GA-simulation approach is used in an interactive manner to determine the optimal/near-optimal number of kanban cards in different stations of the existing JIT system. The presented hybrid approach is tested and applied to an auto industry production line. Furthermore, it is compared with the practical JIT through analysis of variance (ANOVA) and the results show improvements in the average daily production rate, the average resource utilisation and the average cycle time but some deterioration in the average queue length and in-process inventory is inevitable.     

Current Approaches in Improving Hemocompatibility of Polymeric Membranes for Biomedical Application

Suitable membranes for blood‐contacting medical applications need to be resistant in confrontation with blood proteins and cells, while possessing high blood compatibility and permeability at the same time. Herein, an overview of the recent advances and strategies that have been used to enhance the hemocompatibility of polymeric membranes is provided. The review focuses on two modification strategies: (i) physical modifications and (ii) chemical modifications. It also highlights the current progress in the design of hemocompatible‐functionalized membranes for biomedical applications. Subsequently, the commonly applied biocompatibility tests are also discussed and finally the future perspectives of the application of polymeric membranes in the biomedical field are presented.