Properties of Phragmites australis for Insulating Concrete Application

The common reed, Phragmites australis, is a plant species quite similar to the currently used bio-based aggregates and available on most continents. The purpose of this work is to characterise this common reed and compare its properties to other plants already studied for building use. This study presents the different properties focussing on Phragmites australis chemical composition, hydrophobicity nature and how this character could be explained. To that end, wettability and also water adsorption measurements were carried out on plant flour and aggregates in comparison to miscanthus, wood and hemp shiv properties. Formulations based on reeds of different origins and using different binders (lime and earth) were tested in compression and with thermal conductivity measurements in order to evaluate the behaviour of the reed as a material for building use.

Quantifying the optimal thickness in polymer:fullerene solar cells from the analysis of charge transport dynamics and photoabsorption

We provide a semi-empirical equation that quantifies the optimal layer thickness in bulk heterojunction organic solar cells, which is based on time-of-flight and time-resolved microwave conductivity measurements and photoabsorption of a film.

The Transport Properties of Quasi–One-Dimensional Ba3Co2O6(CO3)0.7

We have performed combined elastic neutron diffuse, electrical transport, specific heat, and thermal conductivity measurements on the quasi–one-dimensional Ba3Co2O6(CO3)0.7 single crystal to characterize its transport properties. A modulated superstructure of polyatomic CO32− is formed, which not only interferes the electronic properties of this compound, but also reduces the thermal conductivity along the c-axis. Furthermore, a large magnetic entropy is observed to be contributed to the heat conduction. Our investigations reveal the influence of both structural and magnetic effects on its transport properties and suggest a theoretical improvement on the thermoelectric materials by building up superlattice with conducting ionic group.

Ultrathin Metal-Organic Framework Nanosheets and Devices

A few recent findings on ultrathin two-dimensional (2D) metal-organic frameworks (MOFs) were discussed in this spotlight review. MOFs are a class of materials with intriguing properties for possible applications in several fields ranging from catalysis to sensors and functional devices. To date, several synthesis strategies have been explored to derive crystalline 2D MOF structures. However, most synthetic strategies to obtain such materials remain underexplored. This highlighted review evaluated select synthesis strategies focused on deriving micron-sized 2D MOF crystals, emphasizing their rich chemistries. More importantly, the possibility of integrating the synthesized ultrathin 2D crystalline MOFs into the functional device and their electrical conductivity measurements are reviewed. Overall, this review provides the most recent outcomes in the ultrathin 2D MOF community and its influence on electronic devices.

Untersuchung von Ionischen Flüssigkeiten unter Stromfluss

Every year 23 % of the world energy consumption is caused by friction and wear. Especially now and in future bearings and gear boxes will be exposed to electrical currents so lubricants have to prevent the components from new damage mechanism. The usage of Ionic Liquids as conductible lubricant additives is in discussion for a longer period of time, but right now it was not investigated how these liquids could be affect by electrical currents itself. Generally, lubricants in industry are compounded by base oils, additives, and thickeners. All these ingredients are isolators and not able to discharge electrical currents. In these joint research project, different Ionic Liquids with different conductivities have been exposed to defined electrical currents. For that experiments a new current feed setup has been developed, where the liquids and model lubricants were exposed to electrical currents under temperature control. The influence on the liquids by the current feed was chemically quantified by using IR-Spectroscopy, rheology and conductivity measurements. The Ionic Liquids react, depending on their chemical structure, very different on the current feeds, some of them has been destroyed totally.

Thermal Conductivity of Detonation Nanodiamond Hydrogels and Hydrosols by Direct Heat Flux Measurements

The methodology and results of thermal conductivity measurements by the heat-flow technique for the detonation nanodiamond suspension gels, sols, and powders of several brands in the range of nanoparticle concentrations of 2–100% w/w are discussed. The conditions of assessing the thermal conductivity of the fluids and gels (a FOX 50 heat-flow meter) with the reproducibility (relative standard deviation) of 1% are proposed. The maximum increase of 13% was recorded for the nanodiamond gels (140 mg mL−1 or 4% v/v) of the RDDM brand, at 0.687 ± 0.005 W m−1 K−1. The thermal conductivity of the nanodiamond powders is estimated as 0.26 ± 0.03 and 0.35 ± 0.04 W m−1 K−1 for the RUDDM and RDDM brands, respectively. The thermal conductivity for the aqueous pastes containing 26% v/v RUDDM is 0.85 ± 0.04 W m−1 K−1. The dignities, shortcomings, and limitations of this approach are discussed and compared with the determining of the thermal conductivity with photothermal-lens spectrometry.

Characterization of European Medieval Silver Bars Using Micro X-ray Fluorescence, Conductivity Meter and Scanning Electron Microscopy

The objective of this paper is to use μ-X-ray fluorescence (XRF) analysis to evaluate the fineness and components of European Medieval Silver Bars samples. Conductivity measurements were used to assess the fineness and localization of the faults found in the samples. Because unevenness causes a change in conductivity, the tests were performed on the flattest areas of the Bars. Some rods, such as B3 and B9, have greater conductivity than others. All bars were subjected to the segregation test. In the instance of certain bars, it was not always practicable to categorically state that segregation had happened. There is no diminishing conductivity curve as one moves away from the zero height, as there is for bars B1, B8, and B9. As a result, there may be no solidification on these bars from Obverse to Reverse. A scanning electron microscope was used to record the following bars at various positions on the bars, and quantitative determinations were achieved using energy-dispersed XRF analysis through intensity measurements of the element-specific wavelength.