Fabrication and characterization of Ru-doped LiCuFe2O4 nanoparticles and their capacitive and resistive humidity sensor applications

Polycrystalline ruthenium-doped lithium-copper-ferrite ( Ru-LiCuFe2O4) nanoparticles (NPs) are synthesized using a simple and cost-effective chemical co-precipitation method and annealed at different temperatures for increasing the crystallinity. The transmission and scanning electron microscopy images have confirmed the presence of soft agglomerations and cuboids for the samples annealed at 1100 °C. X-ray photoelectron results along with Raman spectra have collectively demonstrated the presence of Ru in the structure of Ru-LiCuFe2O4 NPs. The dielectric properties of as-synthesized Ru-LiCuFe2O4 NPs are investigated using LCR meter where the smaller NPs demonstrates a higher dielectric constant. Also, the results of magnetic measurements of annealed Ru-LiCuFe2O4 NPs have corroborated a soft magnetic nature due to the pinning sites that endow lower coercivity, remanence and saturation magnetization than that of the pristine one. The variation of permittivity and electrical resistivity with respect to frequency under humidity conditions suggested that this material has a potential to use as capacitive and resistive humidity sensor. The results of this study open the doors for utilization of metal-doped magnetic ferrites for humidity sensing application

Results from the kaonic hydrogen X-ray measurement at DAFNE and outlook to future experiments

The $\overline{K}N$ system at rest plays a key role for the understanding of strong interaction of hadrons with strangeness involved. The experiment SIDDHARTA used X-ray spectroscopy of kaonic atoms to measure the strong interaction induced shift and width of the ground state. It was the first experiment on kaonic He3 and deuterium ever, kaonic hydrogen was measured with improved precision resulting in \epsilon_{1s} = -283 \pm 36 \mbox{(stat)} \pm 6 \mbox{(syst)} eV and \Gamma_{1s} = 541 \pm 89 \mbox{(stat)} \pm 22 \mbox{(syst)} eV. Additionally a scheme for an improved future experiment on kaonic deuterium is introduced in this contribution

Annealing Temperature Effects on Humidity Sensor Properties for Mg_0.5W_0.5Fe₂O₄ Spinel Ferrite

The effects of annealing temperature on the structural, physical and humidity sensing properties of stoichiometric Mg0.5W0.5Fe2O4 spinel ferrite are investigated. In order to highlight the influence of sintering temperature on the structural, magnetic and electrical properties, ferrite samples were sintered for 2 h at 850 °C, 900 °C, 950 °C, 1000 °C and 1050 °C and the physical properties and humidity influence on magnesium-tungsten ferrite materials were analyzed. X-ray diffraction investigations confirmed the formation of magnesium-tungsten ferrite in the analyzed samples. SEM micrographs revealed the influence of annealing temperature on the microstructures of the samples and provided information related to their porosity and crystallite shape and size. This material, treated at different temperatures, is used as an active element in the construction of capacitive and resistive humidity sensors, whose characteristics were also investigated in order to determine the most suitable sintering temperature

Influence of Sb³⁺ Cations on the Structural, Magnetic and Electrical Properties of AlFeO₃ Multiferroic Perovskite with Humidity Sensors Applicative Characteristics

The effects of Sb3+ cations substitution on the structural, magnetic and electrical properties of Al1−xSbxFeO3 multiferroic perovskite are investigated. The partial or total substitution of Al3+ cations with Sb3+ cations, in stoichiometric composition Al1−xSbxFeO3 (x = 0.00, 0.25, 0.50, 0.75 and 1.00) were made in order to identify composite materials with sensors applicative properties. Multiferroic perovskite samples were prepared following technology of the ceramic solid-state method, and the thermal treatments were performed in air atmosphere at 1100 °C temperature. The X-ray diffraction studies have confirmed the phase composition of samples and scanning electron microscopy the shape of the crystallites has been evidenced. The perovskite material was subjected to representative magnetic investigations in order to highlight substitutions characteristics. Investigations on electrical properties have evidenced the substitution dependence of relative permittivity and electrical resistivity under humidity influence and the characteristics of humidity sensors based on this material. The results are discussed in term of microstructural changes induced by the substitutions degree and its sensor applicative effects

Some Spinel Oxide Compounds as Reducing Gas Sensors

Four spinel ferrites, MFe2O4 (M = Cu, Cd, Zn and Ni), having various grain sizes (100 – 700 nm) were prepared by sol-gel-selfcombustion and their sensing properties to reducing gases were investigated. The gas sensing characteristics were obtained by measuring the sensitivity as a function of various controlling factors, like operating temperature, composition and concentration of the gas, and finally the response time. The sensitivity of four ferrites to reducing gases like acetone, ethanol and LPG was been compared. It was revealed that CuFe2O4 is the most sensitive to LPG and ZnFe2O4 can be used as a sensor to selectively detect ethanol vapors in air. The strong interaction between ethanol and porous ZnFe2O4 can explain the selective sensitivity to ethanol and negligible sensitivity to the other reducing gases

Humidity sensors applicative characteristics of granularized and porous Bi 2 O 3 thin films prepared by oxygen plasma-assisted pulsed laser deposition

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MAGNETIC WOVEN FABRICS - PHYSICAL AND MAGNETIC PROPERTIES

A coated material is a composite structure that consists of at least two components: base material and coating layer. The purpose of coating is to provide special properties to base material, with potential to be applied in EMI shielding and diverse smart technical fields. This paper reports the results of a study about some physical and magnetic properties of coated woven fabrics made from cotton yarns with fineness of 17 metric count. For this aim, a plain woven fabric was coated with a solution hard magnetic polymer based. As hard magnetic powder, barium hexaferrite (BaFe12O19) was selected. The plain woven fabric used as base has been coated with five solutions having different amounts of hard magnetic powder (15% - 45%) in order to obtain five different magnetic woven fabrics. A comparison of physical properties regarding weight (g/m2), thickness (mm), degree of charging (%) and magnetic properties of magnetic woven samples were presented. Saturation magnetizing (emu/g), residual magnetizing (emu/g) and coercive force (kA/m) of pure hard magnetic powder and woven fabrics have been studied as hysteresis characteristics. The magnetic properties of the woven fabrics depend on the mass percentage of magnetic powder from coating solution. Also, the residual magnetism and coercive field of woven fabrics represents only a part of bulk barium hexafferite residual magnetism and coercive field

Urban Shrinking Cities in Romania and The Netherlands—A Possible Policy Framing

In the last decades of the 20th century, the patterns of urban shrinkage defined a worldwide phenomenon. They are visible in all developed regions, especially in Central and Eastern Europe, on the background of the economic growth trajectories and social health improvements. Despite this fact, the public discourse in a post-socialist country such as Romania is only focused on urban decline and its demographic dynamics sliding, when in fact urban shrinkage is more advanced, even to the point of becoming a selective phenomenon in developed countries such as The Netherlands. Our focus on urban shrinkage was driven by the fact that Romania can develop a policy framing regarding urban shrinkage, using example practices from a developed country such as The Netherlands. Moreover, it can learn how to deal with urban shrinkage effects by establishing certain differences which can cope with veritable lessons from both sides. This paper firstly investigates the urban shrinkage phenomenon observed in three cities in Romania and in three cities in The Netherlands. Secondly, it presents an analysis of demographic statistical data using the shift-and-share method to emphasize the persistence of urban shrinkage in the age structure of the total population of shrinking cities from both regions. Thirdly, it offers some lessons from both countries, finally presenting a mutual learning framework that can be applied to other regions in Europe