A geographic information system‐based model for economical and eco‐friendly high‐speed railway route determination using analytic hierarchy process and least‐cost‐path analysis

In this study, geographic information system (GIS)‐based network analysis and analytic hierarchy process (AHP) methods were applied to the Erzincan–Trabzon segment of the Turkish high‐speed railway (HSR) project. A new hybrid route, which considers both economic and environmental criteria, was created and compared with three different routes from various preconstruction studies. The route‐generating analysis included the eight parameters (criteria) of slope, geology, soil quality, rivers, protected areas, roads, land cover, and lakes. The optimum route for connecting the port of Trabzon to Turkey's interior via HSR was generated. The weights for determining the route were tested for sensitivity. The study demonstrated the efficiency of GIS and AHP integration in generating optimum routes for HSR projects according to given databases. All these GIS and AHP analyses were applied automatically with our novel GIS extension for determining optimum HSR routes. The final route has preserved cultural and historical structures, environmental integrity. The new hybrid route also decreased construction costs by approximately 12%, and the least‐cost‐path analysis confirmed the environmental efficiency of the route.     

Polyol Approach for the Synthesis of Water Soluble Mn3O4 Nanoparticles Using PEG

Polyethylene glycol (Mwt 400 and 10,000) stabilized Mn₃O₄ nanoparticles were synthesized via the thermal decomposition approach. Structural characteristics were evaluated by XRD, FT-IR, TGA, VSM, and TEM analysis. Crystallite sizes were calculated as 10±3 and 15±5?nm for PEG-400 and PEG-10,000 stabilized Mn₃O₄ NPs, respectively. FT-IR and TGA proved the presence of PEG on the surface of Mn₃O₄ NPs. Magnetization measurements carried out at room and low temperatures revealed the superparamagnetic nature of the Mn₃O₄ NPs. The blocking temperature was detected as 39?K and thermomagnetic irreversibility starts at 40?K. Both coercive field and saturation magnetization increases as temperature decreases below T _C. Reduced magnetization compared to its bulk value has been explained by spin canting and presence of disordered spins. It was observed that the effects of different molecular weight PEG on the magnetic properties of the Mn₃O₄ nanoparticles are more or less the same.     

Investigation of acetyl ferrocene migration from hydroxyl‐terminated polybutadiene based elastomers by means of ultraviolet–visible and atomic absorption spectroscopic techniques

Migration and leakage of some mobile components in rocket propellant produces an inhomogeneous composition region at which migration takes place, which can lead to premature detonation, changes in ballistic characteristics, and so on. It is, therefore, important to be able to predict the behavior of low‐molecular‐weight mobile additives and to control the leakage of them from the propellant. At this point, our chief interest was to study the magnitude of the migration and to understand the factors that influence the migration process. In this study, the migration of a ferrocene‐based burning‐rate catalyst [acetyl ferrocene (AcF)] a from hydroxyl‐terminated polybutadiene (HTPB) based elastomer in the presence of a plasticizer (dioctyl adipate) was examined in accelerated aging conditions at 60°C for various time intervals. We also tried to minimize the migration of AcF from the loaded to the unloaded part by using an extra barrier layer consisting of polyfunctional aziridine (AST D45+) in addition to the HTPB–toluene diisocyanate composition. The migration enhanced with aging of the AcF and the barrier effects of the layer with intensified crosslink density to this migration were studied extensively. The migration was monitored by both ultraviolet–visible and atomic absorption spectroscopy (AAS) methods. A comparison of the data obtained from both of these methods was also done. The two techniques were found to be in agreement, and the Fe determinations from both methods were highly correlated, suggesting that the data were reliable, although the AAS data were found to be symmetrically somewhat higher. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1654–1661, 2005     

FinFET domino logic with independent gate keepers

Scaling of single-gate MOSFET faces great challenges in the nanometer regime due to the severe short-channel effects that cause an exponential increase in the sub-threshold and gate-oxide leakage currents. Double-gate FinFET technology mitigates these limitations by the excellent control over a thin silicon body by two electrically coupled gates. In this paper a variable threshold voltage keeper circuit technique using independent-gate FinFET technology is proposed for simultaneous power reduction and speed enhancement in domino logic circuits. The threshold voltage of a keeper transistor is dynamically modified during circuit operation to reduce contention current without sacrificing noise immunity. The optimum independent-gate keeper gate bias conditions are identified for achieving maximum savings in delay and power while maintaining identical noise immunity as compared to the standard tied-gate FinFET domino circuits. With the variable threshold voltage double-gate keeper circuit technique the evaluation speed is enhanced by up to 49% and the power consumption is reduced by up to 46% as compared to the standard domino logic circuits designed for similar noise margin in a 32 nm FinFET technology.     

Culture-led regeneration of Istanbul waterfront: Golden Horn Cultural Valley Project

The regeneration of declining waterfronts has been one of the crucial tasks of urban policy since the 1970s; whereas culture has become an important theme as means for responding to the socio-economic decline that waterfronts have been facing through the re-functioning of abandoned factories and warehouses, the rehabilitation of historic neighborhoods and the utilization of events and amenities. At the same time, many academics are critical on the attempts to reform post-industrial spaces of consumption in creating privatized spaces and commodified cultures excluding social milieu. Within this context, the research attempts to discuss the contribution of culture-led approaches in the regeneration of Istanbul waterfront by using a case study of the Golden Horn Cultural Valley Project (GHCVP) as empirical evidence. The GHCVP is not only one of the most important indicators of wider governmental emphasis on culture as a way of reviving Istanbul’s waterfront; but also it provides major discussions and claims on the impact of these developments, especially those regarding the historic environment, local community and economy. The results of this research respond to questions about what makes waterfront regeneration a success and what role the culture-led approaches should play in the process of waterfront regeneration.     

Instrumented indentation and scratch testing evaluation of tribological properties of tin-based bearing materials

This paper describes a study of some fundamental tribological behavior of two different tin-based bearing materials using scratch and Martens hardness techniques. The scratch test results obtained from the two different tin-based bearing materials were correlated with a function of scratch hardness and coefficient of friction. It is easily observed that the friction coefficients of WM5 are lower than those of WM2 under all scratch test conditions. Beside this, it is clearly distinguished that both materials give higher friction coefficients at higher normal loads and scratch velocities. Also it is found that scratch hardness values of the WM5 materials are higher than WM2 generally. Moreover, optical microscopy was used to determine the scratch hardness of two different tin-based bearing materials by examining the scratch widths. Scanning electron microscopic observations of two different tin-based bearing materials were performed in order to identify the scratch-deformation mechanisms and trace morphology. Beside scratch tests, Martens hardness tests were carried out to evaluate the indentation of materials by considering both the force and displacement during plastic and elastic deformation. By monitoring the complete cycle of increasing and removal of the test force, hardness values were determined.     

Overall equipment effectiveness when production speeds and stoppage durations are uncertain

Evaluation of manufacturing equipment performance has been very important in production-related functions such as planning, scheduling, and maintenance. Nevertheless, low accuracy of performance measurements can mislead decision makers. In this study, overall equipment effectiveness (OEE) is considered as a performance indicator of manufacturing equipment. In practice, components of OEE may consist of uncertainty due to manual or semi-automatic measurement systems. As a consequence, true performance of equipment may be masked by the uncertainty of measurements. In this study, two types of uncertainty are considered in production speed and stoppage duration measurements, which are used in calculating OEE components. When the measurements have uncertainty due to use of linguistic terms or some minor stoppages, idling, or speed losses being ignored, fuzzy arithmetic is used as a method to handle uncertainty. In some low accuracy cases, best guess interval estimates of operators may better reflect the state than just providing a point estimate. For such cases, interval arithmetic is used as a method to handle uncertainty. Implementation of the methods are illustrated using two real-world examples and a software is provided for practitioners. Proposed methods help making better informed decisions using OEE under measurement uncertainty of production speed and stoppage durations.     

A complementary electrochromic device with highly improved performance based on brick-like hydrated tungsten trioxide film

Uniform and well adhesive nanostructured hydrated tungsten trioxide (3WO3 x H2O) films were grown on fluorine doped tin oxide (FTO) substrate via a facile and template-free crystal-seed-assisted hydrothermal method by addition of ammonium sulfate ((NH4)2SO4) and hydrogen peroxide (H2O2). X-ray diffraction (XRD) studies indicated that the films are of orthorhombic structure. Scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM) analysis showed that the film was composed of brick-like nanostructures with a preferred growing direction along (002). The influence of seed layer, (NH4)2SO4 and H2O2 on the products were also studied. The film showed good cyclic stability, comparable switching speed and coloration efficiency (30.1 cm2 C(-1)). A complementary electrochromic device based on the film and Prussian blue depicted highly improved color contrast, coloration/bleaching response (1.8 and 3.7 s respectively) and coloration efficiency (164.6 cm2 C(-1)).