Vapor‐induced swelling of supported methacrylic and siloxane polymer films: Determination of interaction parameters

White light reflectance spectroscopy is applied to monitor vapor‐induced thickness changes of polymer films, supported on suitable silicon substrates. Assuming unidirectional swelling due to the constraining support, the equilibrium volume swelling of four methacrylic polymers and two siloxane‐based copolymers upon exposure to various activities of water, methanol, ethanol, and ethyl acetate vapor, at 30°C is evaluated. The deduced sorption isotherms were fitted to the Flory‐Huggins equation and interaction parameters, as well as solubility coefficients at infinite solute dilution, were deduced for each binary system. The relative sorption capacity of the different classes of polymers toward the four vapors are in line with the expected solubility interactions between solvent and solute. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Energy‐efficient management using a traffic‐oriented routing scheme for cognitive radio networks

This paper elaborates on a traffic manipulation routing scheme that associates the moments of the traffic, targeting the maximization of the energy conservation, as well as the effective resource management of the network nodes. The energy conservation is achieved through the data flow coordination, in association with the data traffic volume and the resource exchange, between the nodes that exploit radio spectrum access in cognitive radio networking architectures. The routing scheme that is proposed in this paper interrelates the backward difference of traffic moments for each node based on a series model, together with the sleep‐time period, towards reflecting this measurement to the minimization of the nodes activity durations to achieve energy conservation. The effective operation of the routing scheme is achieved by exploiting a signalling mechanism that was adopted for the proper communication of the nodes over the available radio spectrum parts, such as the television white spaces. Simulation tests were conducted towards examining the validity of the proposed routing scheme via multiple performance evaluation experiments. Simulation results have shown the offered reliability and the efficiency of the proposed traffic‐aware scheme, in reference to the efficient energy consumption of the networking nodes and the minimization of the delays. Copyright © 2015 John Wiley & Sons, Ltd.     

Electrochemical oxidation of stabilized landfill leachate on DSA electrodes

The electrochemical oxidation of stabilized landfill leachate with 2960 mg L(-1) chemical oxygen demand (COD) over a Ti/IrO(2)-RuO(2) anode was investigated in the presence of HClO(4) as the supporting electrolyte. Emphasis was given on the effect of electrolysis time (up to 240 min) and temperature (30, 60 and 80°C), current density (8, 16 and 32 mA cm(-2)), initial effluent's pH (0.25, 3, 5 and 6), HClO(4) concentration (0.25 and 1M) and the addition of NaCl (20 and 100mM) or Na(2)SO(4) (20mM) as source of extra electrogenerated oxidants on performance; the latter was evaluated regarding COD, total carbon (TC), total phenols (TPh) and color removal. Moreover, the anode was studied by scanning electron microscopy and cyclic voltammetry. The main parameters affecting the process were the effluent's pH and the addition of salts. Treatment for 240 min at 32 mA cm(-2) current density, 80°C and the pH adjusted from its inherent value of 0.25 (i.e. after the addition of HClO(4)) to 3 yielded 90% COD, 65% TC and complete color and TPh removal at an electricity consumption of 35 kWh kg(-1) COD removed. Comparable performance (i.e. 75% COD reduction) could be achieved without pH adjustment but with the addition of 100mM NaCl consuming 20 kWh kg(-1) COD removed.     

Temperature and nonlinearity corrections for a photodiode array spectrometer used in the field

Temperature and nonlinearity effects are two important factors that limit the use of photodiode array spectrometers. Usually the spectrometer is calibrated at a known temperature against a reference source of a particular spectral radiance, and then it is used at different temperatures to measure sources of different spectral radiances. These factors are expected to be problematic for nontemperature-stabilized instruments used for in-the-field experiments, where the radiant power of the site changes continuously with the sun tilt. This paper describes the effect of ambient temperature on a nontemperature-stabilized linear photodiode array spectrometer over the temperature range from 5?°C to 40?°C. The nonlinearity effects on both signal amplification and different levels of radiant power have also been studied and are presented in this paper.     

Effects of lithography non-uniformity on device electrical behavior. Simple stochastic modeling of material and process effects on device performance

Understanding how lithographic material and processing, affect linewidth roughness (LWR), and finally device operation is of immense importance in future scaled MOS transistors. The goal of this work is to determine the impact of LWR on device operation and to connect material and process parameters with it. To this end, we examine the effects of photoresist polymer length and acid diffusion length on LWR and transistor performance. Through the application of a homemade simulator of the lithographic process, it is shown that photoresists with small polymer chains and small acid diffusion lengths form lines with low LWR and thus lead to transistors with more reliable electrical performance.     

Using areal interpolation methods in geographic information systems

This paper reports on a research project concerned with the areal interpolation problem — the problem of comparing different data sets when they have been made available for different zonal systems. Our approach is based on using additional information to guide the interpolation process. This paper emphasizes recent work applying the method to Poisson and binomially distributed data. There is also discussion of how the method can best be implemented in a geographic information system.     

Drifts exhibited by cryogenically cooled InSb infrared filtered detectors and their importance to the ATSR-2 and Landsat-5 Earth observation missions

The spectral responsivity of commercially available InSb detectors with low-pass cold filters attached to their cold shields for optimum operation in the 1.6-2.6 microm wavelength range is observed to drift slowly with time. These drifts are shown to arise because of a thin film of water-ice deposited on the cold low-pass filters mounted on the cold shields of the detectors. The temporal characteristics of these drifts are shown to strongly depend on wavelength. A model is proposed for the behavior of the water present in the Dewar vacuum, which can explain and predict the temporal characteristics of the observed drifts for all wavelengths. These observations are particularly relevant to space instruments that use cryogenically cooled IR filter radiometers for Earth observation. The temporal profile of drifts observed in missions such as Landsat-5 is identical to that observed in cryogenically cooled filtered InSb detectors during laboratory measurements. This study confirms that the deposition of a thin film of a material such as ice on the cold bandpass filters and windows is therefore the most likely source of the oscillatory drifts observed in the response of some of the channels of the ATSR-2, Landsat-4, and Landsat-5 Earth observation missions.     

Washing enhanced electrokinetic remediation for removal cadmium from real contaminated soil

The main objective of this study is to evaluate the combination of electrokinetic remediation and soil washing technology in order to remove cadmium from contaminated soil. This paper presents the results of an experimental research undertaken to evaluate different washing and purging solutions to enhance the removal of cadmium from a real contaminated soil during electrokinetic remediation. Two different experimental modules were applied in the laboratory. Soil was saturated with tap water, while acetic and hydrochloric acids, as well as ethylenediaminetetraacetic acid (EDTA) were used as purging solutions in the first module. Results show that there was a decrease of cadmium concentration near anode, but a significant increase in the middle of the cell, due to the increasing pH. Citric, nitric and acetic acids were used for soil washing and purging solutions in the second module. In this case, an 85% reduction of cadmium concentration was achieved. Therefore, results indicate that soil pH and washing solutions are the most important factors in governing the dissolution and/or desorption of Cd in a soil system under electrical fields.