A novel hydrazine electrochemical sensor based on a zirconium hexacyanoferrate film-bimetallic Au–Pt inorganic–organic hybrid nanocomposite onto glassy carbon-modified electrode

This work describes the electrochemical behavior of zirconium hexacyanoferrate (ZrHCF) film immobilized on the surface of bimetallic Au–Pt inorganic–organic hybrid nanocomposite glassy carbon electrode and its electrocatalytic activity toward the oxidation of hydrazine. The electrode possesses a three-dimensional (3D) porous network nano architecture (NFs). The surface structure and composition of the sensor was characterized by scanning electron microscopy (SEM). Electrocatalytic oxidation of hydrazine on the surface of modified electrode was investigated with cyclic voltammetry and chronoamperometry methods and the results showed that the ZrHCF film displays excellent electrochemical catalytic activities toward hydrazine oxidation. The modified electrode indicated reproducible behavior and high level of stability during the electrochemical experiments.     

Performance of nanostructure Fe-Ag-ZSM-5 catalysts for the catalytic oxidation of volatile organic compounds: Process optimization using response surface methodology

Gas phase catalytic oxidation of ethyl acetate was studied in low concentration over Fe-Ag-ZSM-5 catalysts under atmospheric pressure. The effect of important parameters such as Ag loading, Fe loading, calcinations temperature and reaction temperature was investigated and the process conditions were optimized using response surface methodology (RSM) based on central composite design (CCD). The optimum condition for Ag loading, Fe loading, calcination temperature and reaction temperature was 5.17 wt%, 2 wt%, 580 °C and 350 °C, respectively. A maximum of 96% of ethyl acetate was removed under the optimum experimental conditions. The proposed model equation using RSM has shown good agreement with the experimental data, with a correlation coefficient (R²) of 0.949.     

Kernel-Based Positioning in Wireless Local Area Networks

The recent proliferation of location-based services (LBSs) has necessitated the development of effective indoor positioning solutions. In such a context, wireless local area network (WLAN) positioning is a particularly viable solution in terms of hardware and installation costs due to the ubiquity of WLAN infrastructures. This paper examines three aspects of the problem of indoor WLAN positioning using received signal strength (RSS). First, we show that, due to the variability of RSS features over space, a spatially localized positioning method leads to improved positioning results. Second, we explore the problem of access point (AP) selection for positioning and demonstrate the need for further research in this area. Third, we present a kernelized distance calculation algorithm for comparing RSS observations to RSS training records. Experimental results indicate that the proposed system leads to a 17 percent (0.56 m) improvement over the widely used K-nearest neighbor and histogram-based methods     

A simulated annealing algorithm for multi-manned assembly line balancing problem

Assembly line balancing problems with multi-manned workstations usually occur in plants producing high volume products (e.g. automotive industry) in which the size of the product is reasonably large to utilize the multi-manned assembly line configuration. In these kinds of assembly lines, usually there are multi-manned workstations where a group of workers simultaneously performs different operations on the same individual product. However, owing to the high computational complexity, it is quite difficult to achieve an optimal solution to the balancing problem of multi-manned assembly lines with traditional optimization approaches. In this study, a simulated annealing heuristic is proposed for solving assembly line balancing problems with multi-manned workstations. The line efficiency, line length and the smoothness index are considered as the performance criteria. The proposed algorithm is illustrated with a numerical example problem, and its performance is tested on a set of test problems taken from literature. The performance of the proposed algorithm is compared to the existing approaches. Results show that the proposed algorithm performs well.     

Fuzzy cognitive maps and cellular automata: An evolutionary approach for social systems modelling

One of the first decisions to be made when modelling a phenomenon is that of scale: at which level is the phenomenon most appropriately modelled? For some phenomena the answer may seem too obvious to warrant even asking the question, but other phenomena cover the gamut, from high to low levels of abstraction. This paper explores how two modelling approaches that are ‘at home’ at opposite ends of the abstraction spectrum can be combined to yield an evolutionary modelling approach that is especially apt for phenomena that cover a wide range in this spectrum.We employ fuzzy cognitive maps (FCMs) to model the interplay between high-level concepts, and cellular automata (CA) to model the low-level interactions between individual actors. The combination of these models carries both beyond their respective limitations: the FCM concept is extended beyond the derivation of equilibrium outcomes from static initial conditions, to time-evolving systems where conditions may vary; CA are extended beyond the emergence of patterns from local interactions, to systems where global patterns have local repercussions.The applicability of the methodology is demonstrated by modelling the spread of human immunodeficiency virus (HIV) in an environment in which injection drug users share paraphernalia.     

Fabrication of a highly selective Eu(III) membrane sensor based on a new S–N hexadentates Schiff''s base

A novel potentiometric membrane Eu (III) ion sensor is described based on a new S–N hexadentates Schiff's base, bis(thiophenol)butane2,3-dihydrazone (SNSB). The sensor exhibited a Nernstian response over a concentration range of 1.0 × 10⁻⁵ to 1.0 × 10⁻² M, with a detection limit of 5.0 × 10⁻⁶ M. The best performance was achieved with a membrane composition of 30% PVC, 63% o-nitrophenyloctyl ether (NPOE), 5% SNSB, and 5% (0.010 mmol) potassium tetrakis(p-chlorophenyl) borate (KTpClPB). It was found that in the pH range of 3.0–8.5, the potential response of the sensor was not affected by the pH. Furthermore, the electrode presented satisfactory reproducibility, very fast response time (<5 s), and relatively good discriminating ability for Eu(III) ions with respect to many common cations and lanthanide ions, including sodium, potassium, magnesium, calcium, copper, nickel, cobalt, zinc, lead, lanthanum, cerium, gadolinium, samarium, ytterbium, presidium, terbium, neodymium, holmium, erbium, thulium, lutetium, dysprosium, iron and chromium metal ions. The sensor was applied to the determination of fluoride ions in two mouth wash preparations and binary mixtures.     

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.     

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.