Study of Thermal Properties on the Different Layers Composing a Commercial Ceramic Tile

In this study the thermal conductivity of a commercial ceramic is determined considering that this property is an essential factor on the building materials. This is the primary indicator of the material suitableness for energy transfer, considering that this kind of construction supplies has many applications as thermal insulations. In this sense, we consider that a commercial tile is usually composed of three layers: substrate, a so-called engine layer, and an enamel layer. Likewise, the thermal properties of the different layers were obtained individually by using two photothermal techniques on the ceramic material; the ceramic tile density was obtained using the Archimedes method. The calculated values show a wide range of thermal conductivity values for the different layers, ranging from1.3 to 4 W m¡1K¡1

Electrical analysis of piezoelectric ceramics of BaTiO3 doped with Cu and Ag

En esta investigación se estudia el efecto de la incorporación de partículas metálicas de cobre (Cu) <75μm y plata (Ag) <100nm, ambas de forma esférica de la marca ALDRICH, en la matriz del cerámico de titanito de bario (BaTiO3). La fabricación de estos materiales se realizó mediante la técnica de polvos; a partir de una mezcla, en un molino de giro planetario formando composiciones químicas en polvo como: BaTiO3 + 1% Cu, BaTiO3 + 3% Cu, BaTiO3 + 1% Ag, BaTiO3 + 3% Ag, BaTiO3 + 1% Cu & Ag, BaTiO3 + 3% Cu & Ag, cada muestra fue de 10 g. Los polvos fueron sometidos a un proceso de prensado para su conformación en muestras de forma cilíndricas y finalmente sinterizadas en un horno eléctrico a una temperatura de 1240 °C. A los materiales se le determinaron sus propiedades eléctricas, así como la determinación de la permitividad relativa del material, la capacitancia y la obtención de sus diagramas de magnitud - frecuencia eléctricas usando un generador de funciones. Los resultados obtenidos muestran que la incorporación de partículas de Cobre y Plata como un reforzamiento metálico en una base cerámica de BaTiO3 modifica las propiedades eléctricas - ferroeléctricas y dieléctricas

Tools for soil understanding: Hot Ball method, XRD, and AC complex conductivity

AbstractThe social dependence on the soil to guarantee its fertility and ensure food security have generated poor management practices globally. Nevertheless, the soil is considered a fundamental factor in the transition towards a sustainable bioeconomy because of its societal importance due to the biomass source to produce value-added products. Soil thermal properties are critical factors because of the microclimate, so fertility and soil chemistry are controlled by the heat exchange between the soil and the surrounding; therefore, knowledge of these parameters is essential to crop planning better. Access to advanced techniques to monitor the growth and quality of crops in rural areas of the Latin American region is scarce. Several characterization techniques have been used to get soil thermal properties but are needed to provide open access to these techniques and obtain higher-resolution data. This study employs the so-called Hot Ball method to obtain thermal conductivity. The effect of particle size, thermal stability, and mineralogical composition on thermal conductivity is studied. Also, soil structure and electrical conductivity are studied. This study is expected to be a tool for making strategic decisions that lead to better planning of crops in the bioeconomy context. [Figure: see text

Thermal properties of maize seed components

AbstractMaize (Zea Mays L.) is one of the cereals most consumed worldwide, not only because of food uses but also because of its industrial uses. Physical processes are used when transforming maize industrially, particularly thermal processes are employed. Because of this, it is necessary to enhance the industrial procedures that constitute the grain processing chain. The additional information that allows advances in procedures and techniques in commodities like cereals gives an advantage to the food industry. The processes that involve temperature are benefiting of thermal properties knowledge. Therefore, maize thermal properties of each component are studied. Three standard varieties of maize seeds (GSV2, SLP, and P6) were thermally characterized. Photopyroelectric and open photoacoustic cell techniques were employed for characterization. The maize analyzed components were pericarp, endosperm (floury and vitreous), and germ. The outer maize layer’s pericarp presents the lowest thermal conductivity for GSV2 and P6 samples, whereas the P6 sample components have similar thermal conductivity values. The obtained results show a thermal impedance between some of the maize components. The presented information can be used to improve the maize thermal process transformation

Electrical response in poled (Bi0.5Na0.5)0.935Ba0.065TiO3 ceramics

A ferroelectric material (Bi0.5Na0.5)0.935Ba0.065TiO3 (BNBT) with a perovskite structure was poled and characterized by electrical impedance spectroscopy as a function of temperature, X-ray diffraction, and Rietveld refinement. The ac conductivity showed a low-frequency dispersion, supporting the idea of heterogeneous potential wells favored by Bi3þ, Naþ, and Ba2þ on the A site of the perovskite type of structure. The activation energies for ac conduction depended on the studied frequency. The permittivity and electrical modulus showed a distribution of the relaxation time associated with the delay in the orientation of the dipoles and an important contribution to the short-range conductivity

Sugar Concentration Measurement System Using Radiofrequency Sensor

A sugar solution measurement system was developed based on the dielectric properties of the sucrose molecule. An ac conductivity and tan &#948; study as a function of the frequency was performed to find the suitable frequency range for the measuring system. The results indicate that it is possible to obtain a better response of the sensor using the frequencies as the maxima peak in tan &#948; appears. Developed setup for sucrose solution was appropriate to measure in a 0.15 to 1 g/mL range with an experimental error of about 3%. The proposed system improves the measurement time over some other methods