Search results for "Moi"
showing 10 items of 2109 documents
Moisture ingress in photovoltaic modules: A review
2021
Abstract Moisture ingress in photovoltaic (PV) modules is the core of most degradation mechanisms that lead to PV module power degradation. Moisture in EVA encapsulant can lead to metal grids corrosion, delamination and discolouration of encapsulants, potential induced degradation, optical and adhesion losses. The present work is a review of literature on the causes, effects, detection, and mitigation techniques of moisture ingress in PV modules. Literature highlights on determining the diffusivity, solubility, and permeability of polymeric components of PV modules via water vapour transmission rate tests, gravimetric, and immersion methods, have been presented. Electroluminescence, photolu…
Sorption properties of torrefied wood and charcoal
2014
AbstractPre-treating biomass by torrefaction is assumed to improve the material's storage properties because of reducing hydrophilicity. In order to assess the effect of sorption on storage properties, the adsorption of water vapour and capillary absorption of liquid water in torrefied and charred spruce and birch were studied. In addition, the chemical changes were evaluated through Fourier Transform Infrared (FT-IR) spectroscopy. Adsorption decreased notably as severity of treatment increased, as was expected due to degradation of the wood constituents, namely hemicelluloses and amorphous cellulose. Capillary absorption increased with increasing severity in spruce samples while birch show…
Multilayer modified NH<inf>4</inf>NO<inf>3</inf> granules with 3D nanoporous structure: Effect of the heat treatment regime o…
2017
The article is devoted to the investigation of the structure of macro- and mesopores on the surface and inside of modified NH4NO3 granules. The main quality indicators of modified NH4NO3 granules are presented and the relationship between the nanoporous structure of granules and the quality indicators is shown. Various thermodynamic conditions for obtaining a nanoporous structure of the surface and internal layers during the modification of granules are considered. The optimal regime for the uniformity of the temperature distribution in the vortex granulator is the regime of mixed motion of the drying agent. In this mode, mainly “modification” pores are formed, “mechanical” pores due to the…
New BODIPY derivatives with triarylamine and truxene substituents as donors for organic bulk heterojunction photovoltaic cells
2021
Abstract We have designed two new BODIPY derivatives, denoted as 6a and 6b, substituted with truxene moiety and triphenylamine (TPA) unit groups and have investigated their optical and electrochemical properties. Dyes 6a and 6b were employed as donor along with PC71BM or Y6 as acceptor for the fabrication of binary and ternary organic solar cells. After optimization of the binary and ternary active layers, we have achieved over all power conversion efficiency (PCE) of 11.37 % and 13.32% for 6a:PC71BM:Y6 and 6b:PC71BM:Y6 ternary organic solar cells, respectively, which are higher than the binary organic solar cells based on PC71BM or Y6 acceptor. The higher power conversion efficiency for te…
X-ray micro-tomography based FEM modelling of hygroexpansion in PLA composites reinforced with birch pulp fibres
2017
This article presents a microscale modelling approach coupled with X-ray computed micro-tomography for the evaluation of material properties of polylactic acid (PLA) reinforced by birch pulp fibers under the effect of moisture. The results in terms of elastic moduli and hygroexpansion deformation were found in good agreement with the measurements taken at different levels of water uptake.
Saddle-like, π-conjugated, cyclooctatetrathiophene-based, hole-transporting material for perovskite solar cells
2019
A flexible, saddle-like, π-conjugated skeleton composed of four fused thiophene rings forming a cyclooctatetrathiophene (CoTh) with four triphenylamines (CoTh-TTPA) is presented as a hole-transporting material (HTM) for perovskite solar cells. The new HTM shows a bright red color stemming from a direct conjugation between the TPA groups and the central CoTh scaffold. This results in a charge transfer band due to the combination of the weak acceptor moiety, the CoTh unit, and the electron-donating p-methoxytriphenylamine groups. CoTh-TTPA exhibits a suitable highest-occupied molecular orbital (HOMO) level in relation to the valence band edge of the perovskite, which ensures efficient hole ex…
Degradation and Recycling of Films Based on Biodegradable Polymers: A Short Review
2019
The environmental performance of biodegradable materials has attracted attention from the academic and the industrial research over the recent years. Currently, degradation behavior and possible recyclability features, as well as actual recycling paths of such systems, are crucial to give them both durability and eco-sustainability. This paper presents a review of the degradation behaviour of biodegradable polymers and related composites, with particular concern for multi-layer films. The processing of biodegradable polymeric films and the manufacturing and properties of multilayer films based on biodegradable polymers will be discussed. The results and data collected show that: poly-lactic…
Effect of Moisture Content on the Processing and Mechanical Properties of a Biodegradable Polyester
2021
This work is focused on the influence of moisture content on the processing and mechanical properties of a biodegradable polyester used for applications in injection molding. The pellets of the biodegradable polyester were exposed under different relative humidity conditions at a constant temperature before being compression molded. The compression-molded specimens were again placed under the above conditions before the mechanical testing. With all these samples, it is possible to determine the effect of moisture content on the processing and mechanical properties separately, as well as the combined effect of moisture content on the mechanical properties. The results obtained showed that th…
Cyclic moisture sorption and its effects on the thermomechanical properties of epoxy and epoxy/MWCNT nanocomposite
2019
The aim of this work was to reveal the moisture absorption&ndash
Transient Moiré rotation patterns in thin colloidal crystals
2010
A high resolution optical microscopy study on low salt charged sphere suspensions settling under gravity reveals the formation of AB-stacked triangular layers via different transient structures. In particular, metastable triangular Moire rotation patterns (formally corresponding to 1 × 1 Rα super structures) with rotation angles α = 27.8° and α = 38.2° are identified.