The effects of thermistor linearization techniques on the T-history characterization of phase change materials

Phase Change Materials (PCMs) are increasingly being used in the area of energy sustainability. Thermal characterization is a prerequisite for any reliable utilization of these materials. Current characterization methods including the well-known T-history method depend on accurate temperature measurements. This paper investigates the impact of different thermistor linearization techniques on the temperature uncertainty in the T-history characterization of PCMs. Thermistor sensors and two linearization techniques were evaluated in terms of achievable temperature accuracy through consideration of both, non-linearity and self-heating errors. T-history measurements of RT21 (RUBITHERM ® GmbH) PCM were performed. Temperature measurement results on the RT21 sample suggest that the Serial-Parallel Resistor (SPR) 1 linearization technique gives better uncertainty (less than ±0.1°C) in comparison with the Wheatstone Bridge (WB) 1 technique (up to ±1.5°C). These results may considerably influence the usability of latent heat storage density of PCMs in the certain temperature range. They could also provide a solid base for the development of a T-history measuring device. © 2012 Elsevier Ltd. All rights reserved

Synthesis and Application of Domestic Glassy Carbon TiO2 Nanocomposite for Electrocatalytic Triclosan Detection

Nanoparticles of TiO2 are suitable for many catalytic and photocatalytic applications due to their extraordinary properties such as superhydrophobicity, semiconductivity, electron-rich, and environmental compatibility. The main crystalline phases of TiO2, anatase, and rutile possess different crystal structures, crystallinity, crystalline sizes, and specific surface areas, and these characteristics directly affect the catalytic performance of TiO2. In the present study, domestic carbon material enhanced with TiO2 nanoparticles was synthesized and used for the construction of a modified carbon paste electrode. The electrocatalytic activity of the modified electrodes was investigated depending on the TiO2 crystalline phases in the electrode material. Furthermore, the obtained working electrode was utilized for triclosan detection. Under optimized experimental conditions, the developed electrode showed a submicromolar triclosan detection limit of 0.07 µM and a wide linear range of 0.1 to 15 µM. The relative standard deviations for repeatability and reproducibility were lower than 4.1%, and with satisfactory selectivity, the proposed system was successfully applied to triclosan monitoring in groundwater. All these results confirm that the sustainable production of new and domestically prepared materials is of great benefit in the field of electrocatalysis and that the morphology of such produced materials is strongly related to their catalytic properties

Popis slapoljuba (Insecta: Coleoptera: Elmidae) Hrvatske s napomenama

In this paper an annotated checklist of Croatian riffle beetles is presented. It is a result of a literature review, revision of museum collections, implementation of results from various environmental impact and baseline studies, as well as field investigations throughout Croatia from 2002–2013. Altogether 23 species in eight genera of Elmidae were identified. Five species are new for the Croatian fauna: Elmis rioloides (Kuwert 1890), Esolus angustatus (Müller 1821), E. pygmaeus (Müller 1806), Oulimnius tuberculatus (Müller 1806) and Stenelmis consobrina Dufour 1835. Furthermore, the occurrence of Elmis aenea (Müller 1806) in Croatia is confirmed.U ovom je radu dat popis slapoljuba Hrvatske s napomenama o njihovoj biologiji i staništima u Hrvatskoj. Rezultat je pregleda literature, uvida u muzejske zbirke, implementacije rezultata stručnih studija i elaborata, kao i prikupljanja vodenih kornjaša tijekom raznih terenskih istraživanja duž Hrvatske u razdoblju od 2002. do 2013. godine. Ukupno su utvrđene 23 vrste slapoljuba s pet novih vrsta za faunu Hrvatske: Elmis rioloides (Kuwert 1890), Esolus angustatus (Müller 1821), E. pygmaeus (Müller 1806), Oulimnius tuberculatus (Müller 1806) i Stenelmis consobrina Dufour 1835. Potvrđena je i prisutnost vrste Elmis aenea (Müller 1806) u Hrvatskoj

The development of Serbian aviation and aviation signal stations and their significance on the Salonica front

The development of human society and human conscience has contributed to the general progress in different spheres. Man, observing the surroundings, has always tended to adjust the environment to his needs. Thus, at one point, looking into the sky, he experienced a desire to fly in the vast space above him and be free like a bird. Such ideas have not just been a dream, but represented a need to test the human capabilities, too. Hence he has started, initially in a primitive way, and later with more sophistication, to contrive mechanisms, which would take him into free and yet unexplored sky. The first balloon flight was performed out in the long gone year of 1783, when the Montgolfier brothers flew over Paris. George Cayley, an English engineer, carried out several flights between 1804 and 1853. He was the first to construct a flying machine with fixed wings and separate systems for take-off, motion and control. In 1874 Felix du Temple de la Croix, a navy officer, constructed a flying device resembling the wings of a bird, with a wheel retracting into the base, a propeller and a 6 HP motor. Clement Ader, a French engineer, constructed in 1890 a flying device called Eole powered by a steam engine with four cylinders, 20 HP and four propellers. Otto Lilienthal, a German civil engineer, managed to perform the first safe flight in history. His scientific approach was adopted by the Wright brothers. Orville and Wilbur Wright constructed the first 'successful' airplane in the world, whose flight on 17 December 1903 was fully controlled. Later on, they developed a fixed airplane wing and introduced electronic adjustments in the airplane

The Impact of One Heat Treated Contact Element on the Coefficient of Static Friction

The subject of the paper includes theoretical considerations, the conducting of experimental tests, and the analysis of exposed test results related to determination of the coefficient of static friction of previously heat-treated contact pairs. One contact element is previously, before the procedure of determining the coefficient of static friction, heated at temperatures in the range of ambient temperature to 280°C and then cooled down to ambient temperature. The results of experimental tests of five different materials show that depending on the heat treatment of one contact element, there is a significant decrease in the coefficient of static friction. The authors of the paper consider that the reasons for the decreasing coefficient of static friction are related to oxide formation and changes in the surface layer of the contact element which is previously heat-treated

VSCAN: An Enhanced Video Summarization using Density-based Spatial Clustering

In this paper, we present VSCAN, a novel approach for generating static video summaries. This approach is based on a modified DBSCAN clustering algorithm to summarize the video content utilizing both color and texture features of the video frames. The paper also introduces an enhanced evaluation method that depends on color and texture features. Video Summaries generated by VSCAN are compared with summaries generated by other approaches found in the literature and those created by users. Experimental results indicate that the video summaries generated by VSCAN have a higher quality than those generated by other approaches.Comment: arXiv admin note: substantial text overlap with arXiv:1401.3590 by other authors without attributio

The Study of Capacitance Change during Electrolyte Penetration through Carbon-Supported Hydrous Ruthenium Oxide Prepared by the Sol-Gel Procedure

The changes in capacitive behavior of C/HxRuOy composite material prepared by impregnating the Vulcan® XC 72R carbon black with oxide sols of different particle size are investigated as the electrolyte penetrates through the thin layer of the Nafion®-covered composite. The techniques of cyclic voltammetry and electrochemical impedance spectroscopy are used. Results of the investigation reveal the influence of potential cycling and the exposure time to the electrolyte on registered capacitive characteristics of composite. The cycling in a wide potential range causes the decrease in energy storage ability which depends on oxide particle size. Impedance measurements, however, show that the ability initially decreases and subsequently increases during exposure to the electrolyte as the consequence of the presence of Nafion® top-layer. Due to wettability and resistance issues, Nafion® top-layer can affect the pseudo-capacitive characteristics, and the energy storage ability of the composite consequently decreases