Partitioning of rare earths and some major elements in the Kizildere geothermal field, Turkey

Rare earth elements and yttrium (REY), Na⁺, K⁺, Cl⁻, and Ca²⁺ were determined in water, steam, mineral scale and rock samples from the Kizildere geothermal field, Turkey. The CO₂-rich parent fluid originates from a sequence of mica schists with marble intercalations. The chemistry of the parent fluid varies with location and time. The average REY composition of the fluids is derived by extrapolation to the lowest Ca concentrations. The apparent vapor–liquid partitioning factors for REY at 145 °C and 5 bar total absolute pressure are about 0.2, whereas for Ca²⁺, Na⁺, K⁺ and Cl⁻ they are <0.05, about 0.0005, 0.0005 and about 0.02, respectively. Apparent scale-liquid distribution coefficients for REY at 145 and 190 °C are about 0.15 and 0.55, whereas at 100 °C they increase from 0.3 (La) to 1.5 (Lu).     

An amino-alkyl siloxane oligomer as hydrophobation agent for particleboards used under high humidity conditions

In this study, an amino-alkyl siloxane oligomer was used as a hydrophobation agent in order to improve the behaviour of particleboards under moist and outdoor weathering conditions and to be compared to conventionally used paraffin waxes. Melamine-urea-phenol-formaldehyde (MUPF, 15.0 %) was used as adhesive and mixed with the hydrophobation agents at concentrations of 1, 3, and 5 % related to the dry particle mass. The siloxane oligomer improved the water-related properties (thickness swelling, water uptake, internal bond strength (IBS) and IBS after boil test) in comparison to a control without hydrophobation agent. It also tended to enhance bending strength, modulus of elasticity, and IBS compared to specimens containing wax. IBS after boil test was significantly higher at addition of 3 and 5 % siloxane than that of wax-added reference boards. Specimens with siloxane oligomer, however, displayed higher thickness swelling and water uptake than those with wax added. It is assumed that the siloxane oligomer is able to contribute to bonding via hydrogen and covalent bonds and particularly enhance wet strength, while waxes exclusively act by their non-polar nature and, thus, water repellent behaviour.     

Heterogeneous catalytic degradation of cyanide using copper-impregnated pumice and hydrogen peroxide

The main objective of this research was to investigate the oxidative destruction of free cyanide with hydrogen peroxide and copper-impregnated pumice as a heterogeneous catalyst. Original or copper-impregnated pumices added alone were not effective adsorbents of negatively charged cyanide ions due to incompatible surface interactions. Peroxide and original pumices added together were also ineffective in removing cyanide. However, for all of the three natural pumices tested with various particle size fractions, the use of copper-impregnated pumices and peroxide together significantly enhanced both the initial rate and extent of cyanide removal. Although copper-impregnated specific surface area was the major factor affecting the rate and extent of cyanide destruction for a particular pumice source with similar surface chemistries, the type of surface chemistry (i.e., specific functional groups) within different pumice sources also appears to be a very important factor. Lower rates and extents of cyanide removals were observed at pH 11 compared to pH 8 probably because of the negative impacts of alkaline conditions in terms of scavenging peroxide and forming more negatively charged pumice surfaces. Both the initial rate and ultimate extent of cyanide removals were generally higher at a temperature of 20 degrees C compared with those found at 10 degrees C. The use of copper-impregnated pumice as a light, cheap, readily available, natural, and porous heterogeneous catalyst either in completely mixed/suspended or fixed-bed reactor configurations may be an effective treatment technology for cyanide removal from solution. This new approach may minimize downstream metal removal problems experienced in conventional cyanide oxidation technologies.     

Experimental and code based study of beam-column behaviour of equal leg single-angles

This study intends to establish the behaviour of equal leg single-angles under bi-axial bending and compression experimentally and analytically using nonlinear finite element analysis techniques. In the experimental system, 100×100×10 nominally sized equal leg single-angles were tested. The legs of angles were placed in a flange-down position, and their axes were restrained laterally as a simply supported beam. These simply supported beams were loaded with a concentrated vertical load applied at the middle of the length and an axial load parallel to the beam axis until failure was reached. The FEM model of the experimental system was generated with ABAQUS software. Suitable finite element mesh configurations, boundary conditions and nonlinear analysis solution techniques were determined to identify the system behaviour. The test and ABAQUS software results were interpreted using some code specifications and one design procedure.     

Transmit Power Distribution of Wireless Ad-hoc Networks with Topology Control

Topology control and routing protocols are used by designers of wireless packet data networks to lower the node degree, simplify routing and lower the nodes' energy consumption, while preserving strong connectivity. We assume a popular fading channel model and study the impact of several topology control schemes on the transmit power of nodes randomly distributed over a large area according to a Poisson point process, where each node controls the pattern of its one-hop neighbors by independently adjusting its transmit power. We provide the distribution of the transmit power of individual nodes under several different topology control algorithms, allowing designers to estimate the life time of battery energized devices, and the implications of choosing the nodes' peak transmit power. We also allow easy comparisons between several different topology control algorithms with respect to the nodes' power consumption.     

Critical Submergence for Multiple Pipe Intakes

The critical submergence for a group of multiple pipe intakes is predicted using a “superposition method” based on a potential flow solution. Experiments on groups of two, three, and four intakes were conducted. Experimental and theoretical results indicate that intakes in a group mutually influence the discharge into an individual intake. Therefore, the critical submergence for an intake in a group becomes larger than that for an isolated intake under identical flow conditions. The agreement between the theoretical and experimental results is found to be satisfactory.     

Implementation of a charge-based neural Euclidean classifier for a3-bit flash analog-to-digital converter

This paper describes the implementation of a Euclidean squared classifier with a charge based synaptic matrix and discriminator, based on a previously implemented Hamming classifier. The discriminator circuit is a generalized n-port version of the two-port differential charge-sensing amplifier that is conventionally used in DRAM's for bitline sensing. Both the quantifier and discriminator are implemented by charge based techniques, granting the simultaneous availability of high integration density, low power consumption, and high speed. The analog-to-digital (A/D) implementation was chosen to illustrate the network's classification characteristics, since A/D conversion can be interpreted as classifying an input in terms of A/D quantization levels. A detailed analysis of the classifier configuration is presented. Design issues are addressed at both the system and circuit levels, and some limitations are identified. Both simulation results and measurements of the implemented chip are presented to confirm the theoretical analysis. The circuit occupies an area of 500 μm×250 μm, operates with a single 5 V power supply, and consumes less than 1 mW of static power     

Critical Submergence for a Rectangular Intake

In this study, the critical submergence for a rectangular intake in a uniform canal flow is investigated. The potential solution for the combination of a line sink and a uniform flow is available and known as Rankine half-body. This study is based on the Rankine half-body. Theoretical and experimental results have indicated that, in general, the critical submergence for a rectangular intake can be predicted by means of a critical sink surface which consists of a critical cylindrical sink surface capped with two critical hemispherical sink surfaces at both ends. The effects of intake-duct pipe blockage and location of impervious boundaries on critical submergence of a rectangular intake are presented. Experiments were conducted on a rectangular intake sited in a dead-end uniform canal flow. The agreement between the theoretical and experimental results is found to be acceptable.     

Mechanics of porous-adsorbent materials

The paper is concerned with the mechanical effects of adsorption in porous materials. A field theory which is suitable for the study of non-uniform deformations of a body composed of a porous-adsorbent material in the presence of an adsorbable gas is developed.     

Artificial intelligence approach to classify unipolar and bipolar depressive disorders

Machine learning approaches for medical decision-making processes are valuable when both high classification accuracy and less feature requirements are satisfied. Artificial neural networks (ANNs) successfully meet the first goal with its adaptive engine, while nature-inspired algorithms are focusing on the feature selection (FS) process in order to eliminate less informative and less discriminant features. Besides engineering applications of ANN and FS algorithms, medical informatics is another emerging field using similar methods for medical data processing. Classification of psychiatric disorders is one of the major focus of medical informatics using artificial intelligence approaches. Being one of the most debilitating psychiatric diseases, bipolar disorder (BD) is frequently misdiagnosed as unipolar disorder (UD), leading to suboptimal treatment and poor outcomes. Thus, discriminating UD and BD at earlier stages of illness could therefore help to facilitate efficient and specific treatment. The use of quantitative electroencephalography (EEG) cordance as a biomarker has greatly enhanced the clinical utility of EEG in psychiatric and neurological subjects. In this context, the paper puts forward a study using two-step hybridized methodology: particle swarm optimization (PSO) algorithm for FS process and ANN for training process. The noteworthy performance of ANN–PSO approach stated that it is possible to discriminate 31 bipolar and 58 unipolar subjects using selected features from alpha and theta frequency bands with 89.89 % overall classification accuracy.