An Application of Genetic Algorithm Search Techniques to the Future Total Exergy Input/Output Estimation

Since 1975, there has been a great deal of interest, particularly during the past decade, in the promising genetic algorithm (GA) and its application to various disciplines from medicine to cogeneration. However, the studies performed on energy-related GA modeling are relatively low in numbers. The main objective of the present study is to develop the exergy input/output estimation equations in order to estimate the future projections based on the GA notion. In this regard, the GA Future Total EXergy Input/Output Estimation Models (GAFTEXIEM/GAFTEXOEM) are used to estimate total exergy input/output demand of Turkey, which is selected as an application country, based on the economic and social indicators of gross domestic product (GDP), population, import, export and house production figures. The future prediction of Turkey's total exergy input/output values are projected between 2003 and 2023. It may be concluded that the models proposed here can be used as an alternative solution and estimation techniques to available estimation techniques. It is also expected that this study will be helpful in developing highly applicable and productive planning for energy policies.     

Solidification/Stabilization of Hazardous Wastes Containing Metals and Organic Contaminants

The potential of solidification/stabilization (S/S) technology for the safe disposal of hazardous wastes has wide spread recognition. The purpose of this study was to investigate the effectiveness of portland cement-based S/S technology for the safe disposal of hazardous wastes containing toxic metals and organic contaminants. As hazardous wastes, metal enriched mining residue, adsorbable organic halogens (AOX) containing pulp and paper sludge, and polychlorinated biphenyl (PCB) oil-contaminated soil were used. For S/S of waste, portland cement as a binding agent was mixed with wastes at different ratios. For initial waste characterization, contaminant concentrations and some physical waste characteristics such as particle-size distribution, Atterberg limits, specific gravity, and moisture content yielding the maximum compacted dry density were determined. Waste and cement mixtures were cured for 28 days after compacting the desired waste-cement mixtures at their predetermined optimum moisture contents yielding the corresponding maximum dry densities in cylindrical molds having a height of 71 mm and a diameter of 36 mm. At the end of the 28-day cure period, unconfined compressive strength and hydraulic conductivity measurements were conducted on the solidified samples. Subsequently, solidified samples were crushed for fractionation into two different aggregate sizes (between 1–2 and >2 mm) and subjected to the U.S. Environmental Protection Agency Toxicity Characteristic Leaching Procedure (TCLP). The effectiveness of S/S was assessed by comparing the chemical composition of leachates obtained from TCLP tests of untreated and treated, i.e., S/S waste samples, and comparing values of strength and hydraulic conductivity of solidified waste samples with regulatory requirements. For mining waste, effective application of S/S was achieved for most cases. AOX containing sludge yielded acceptable results in terms of strength and hydraulic conductivity but leachate AOX concentrations were above regulatory levels. The effectiveness of S/S for coarse textured-soils contaminated with a PCB oil was not satisfactory, especially at a cement:soil ratio less than 35%.     

Accuracy of Ground-Penetrating Radar for Concrete Pavement Thickness Measurement

Core extraction is the most common method for measuring concrete layer thickness in pavement construction. Although this method provides a very accurate thickness measurement, it is destructive, time-consuming, and does not provide adequate representation of the concrete layer thickness variability. Ground-penetrating radar (GPR) is a nondestructive evaluation technique that has been successfully used in several transportation applications, such as subsurface exploration and condition assessment. The main objective of this research is to investigate the accuracy and cost-effectiveness of using GPR in thickness measurement of concrete pavement for quality assurance purposes. A high-resolution 1.6-MHz ground-coupled antenna was used to perform grid scans and measure concrete thickness for several laboratory and field experiments. Results indicated that the use of metal objects underneath the concrete layer to improve bottom surface reflectivity was necessary for a reliable thickness measurement. Also, the use of calibration cores to determine the actual dielectric properties of the concrete was essential for accurate thickness calculation. An average accuracy of 98.5% was achieved when steel plates were used underneath the concrete layer and two cores were extracted for calibration. The effect of concrete age on GPR thickness measurement accuracy was also investigated.     

The mild oxidation of three Tertiary lignites

Three Tertiary lignites have been oxidized with nitrobenzene and sodium hydroxide at 200 °C in a sealed tube. A scheme of extraction has been used to separate the oxidation products and the resulting solutions have been characterized by their infra-red and ultraviolet absorption spectra and by spot tests. The products contain phenolic hydroxyl and carbonyl — rather than carboxyl — groups. Some of the solutions have been reduced and their n.m.r. spectra recorded. The oxidation procedure shows promise as a method of determining the structure of lignites.     

Hilbert–Huang Transform Based Approach for Measurement of Voltage Flicker Magnitude and Frequency

Voltage flicker is a non-stationary waveform for which direct spectral analysis is not appropriate. To overcome this difficulty, a Hilbert–Huang transform based technique is proposed here. Hilbert–Huang transform is a new signal processing method that can be used in the analysis of non-linear and non-stationary signals. In the suggested method, the recorded voltage signal is decomposed into Hilbert–Huang transform components, namely the empirical mode decomposition and intrinsic mode function components. These components are used in the calculation of the frequency and amplitude of voltage flicker. The clear success of empirical mode decomposition in depicting envelope variations of a sinusoidal waveform has been the main motivation for the adoption of Hilbert–Huang transform in flicker analysis. Simulations are performed over waveforms, including single- and multiple-flicker frequencies and flicker with harmonic, voltage sag, and voltage swell. The waveforms are selected as pure sinusoids, as well as harmonically rich voltage waveforms. Simulation results show that the proposed methodology constitutes a plausible way to analyze voltage flickers, making it an alternative to the available flicker analysis tools.     

Utilization of a triple hexagonal split ring resonator (SRR) based metamaterial sensor for the improved detection of fuel adulteration

Journal of Materials Science: Materials in Electronics - In this work, a triple hexagonal split ring resonator incorporated metamaterial sensor is proposed for the improved detection of fuel...