Mathematical and numerical modelling of soiling effects of photovoltaic solar panels on their electrical performance

With time, the photovoltaic solar panels naturally soiled from dust and other elements. These soils prevent light to reach solar cell and can reduce the long-term profitability. The study demonstrates the soiling effect on the electrical characteristics of panels, productivity and performance. A model simulation was developed in this direction in order to quantify and compare the performance of clean and dirty panels, the dust particles have been considered as spheres with an elliptical shadow on the panel. The results prove a power loss of 40% of a 0,224 mg/cm2 dust deposition in comparison with a clean panel at the maximum operating point MPP. This study describes the identified critical parameters governing the fouling of the PV panels

Flexible Smart Textile Coated by PVDF/Graphene Oxide With Excellent Energy Harvesting Toward a Novel Class of Self-Powered Sensors: Fabrication, Characterization and Measurements

Because of some of their diverse benefits, intelligent textiles have attracted a great deal of interest among specialists over the past decade. This paper describes a novel approach to the manufacture of intelligent piezoelectric polymer-based textiles with enhanced piezoelectric responses for applications that extract biomechanical energy. Here we report a highly scalable and ultrafast production of smart textile piezoelectric containing graphene oxide nanosheets (GONS) dispersed in polyvinylidene fluoride (PVDF). In this work, Cotton textiles (CT) were functionalized and by graphene oxide (GO), using PVDF as a binder to obtain a CT-PVDF-GO material. Tetraethyl orthosilicate (TEOS) was further grafted as a coating layer to improve the surface compatibility, resulting in the CT-PVDF-GO-TEOS composite. The research results show that the addition of GONS significantly improves PVDF's overall crystallization rate on CT. More specifically, the piezoelectric β-phase content (100 % higher F[β]) and crystallinity degree on the piezoelectric properties of composite cotton fiber has been improved effectively. Consequently, this fabricated piezo-smart textile has a glorious piezoelectricity even with comparatively low coating content of PVDF-GONS-TEOS. Based on it, the as-fabricated piezoelectric textile device has resulted in the output voltage of up to 13 mV for a given frequency (fm = 8 Hz) at fixed strain amplitude value (0.5 %). It is believed that this research may further reveal the field of energy harvesting for possible applications in the future.. In addition, the set of experimental results that illustrate the smart textile was carried out and discussed, and how it can be used as a wearable device source for this smart textile. Finally, the approach described in this study can also be used to construct other desirable designs, for a wearable low-consumption sensor, etc

Sn replacement influence on magnetic, electronic, thermodynamic, thermoelectric and transport properties in shandite compounds of Co

In this paper, we have investigated some physical properties of Co3In2−xSnxS2 (x = 0, 1, and 2) compounds. The doping in Co3In2S2, through chemical substitution of indium by tin as a low-cost neighboring element, affects their structural, electronic, magnetic, thermodynamic, and thermoelectric properties. The density functional theory (DFT) calculations show that indium substitution leads to a transition from weak-ferromagnetic metal (x = 0), to nonmagnetic semiconductor with low band gap energy at x = 1, and to a ferromagnetic half-metal at x = 2. The thermal properties, obtained by using the Gibbs code, were evaluated with temperature at various pressures from 0 to 20 GPa. The results demonstrated that chemical substitution in the studied materials affects their physical properties leading to an interest candidate for thermoelectric uses at ambient or at low temperature

Critical behavior of Pr

The critical behavior and magnetic properties of Pr0.65Sr0.35MnO3 (symbolized here by PSMO) were studied using Monte Carlo Simulation (MCS). The thermal bath algorithm and Ising model in which exchange interactions via the third nearest neighbor were used to calculate the magnetic and magneto-caloric properties. The effects of temperature (T) and external magnetic field (h) on the magnetic behavior of PSMO were examined. The results show that the Curie temperature (TC) is close to the experimental value. The magnetic entropy shows a maximum value around the TC that increases linearly with the increase of the external field. The critical behavior of the PSMO compound was studied by analyzing the magnetization isotherms and by exploiting Arrott plots. The obtained values of the critical exponents are β = 0.336, γ = 1.121, and δ = 4.335. These values are very close to those reported for the 3D-Ising model. The variation of maximum magnetic entropy ( ΔSmmax Δ S m max ) and relative cooling power (RCP) around the Curie temperature were calculated; the obtained values of ΔSmmax Δ S m max and those of RCP ranging from 3.612 and 92.7 for 1T to 6.191 and 209.9 for 5T, respectively. These results are sufficiently interesting to consider the PSMO compound as a promising candidate for magnetic refrigeration

Additive Manufacturing and Composite Materials for Marine Energy: Case of Tidal Turbine

International audienceThe global trend in additive manufacturing is the technology of three-dimensional (3D) printing with a high potential to avoid some of the weaknesses of conventional fabrication techniques. This new technology has been used to manufacture small tidal and wind turbines. In isolated areas, small turbines can be manufactured and assembled on-site for green energy production. The purpose of this document is to evaluate the thermomechanical behavior of a printed tidal turbine using Digimat-AM (Additive Manufacturing) with fused filament fabrication method. The finite element computes the mechanical deflection, temperature, residual stresses, and warpage fields of the printed part. The composites used during printing are thermoplastic polymers (acrylonitrile butadiene styrene, polyamide 6 [PA6], polyamide 12 [PA12], and polyetherimide [PEI]) reinforced with carbon and glass fillers in the form of fibers and beads (CF/GF and CB/GB). Through the simulation, one could show that the blade printed with PEI-CB/CF has excellent mechanical performance of low mechanical deflection and warpage, compared to PA6-CB/CF. In addition, the fiber-shaped fillers are better than the bead-shaped ones for the 3D printing process. In general, this study has shown the potential and feasibility of 3D printing as an excellent opportunity in the fabrication of small blades in the future, but more studies are required to understand this potential

Mechanical Homogenization of Transversely Isotropic CNT/GNP Reinforced Biocomposite for Wind Turbine Blades: Numerical and Analytical Study

One of the biggest problems facing the use of carbon nanotubes in reinforced composites is agglomeration within the matrix phase. This phenomenon—caused by Van der Waals forces—leads to dispersion problems and weakens the properties of the composites. This research presents a multi-stage homogenization approach used to investigate the influence of the aspect ratio, volume fraction, and agglomeration of the nanofillers on the effective mechanical properties of a polymer biocomposite containing randomly dispersed carbon nanotubes and graphene nanoplatelets. The first stage consisted in evaluating the properties of the reinforced polymers by the CNT/GNP. The second step consisted in combining the reinforced polymers with different natural and synthetic unidirectionally oriented fibers. It was found that agglomeration has a huge influence on the mechanical properties of the composite. The novelty of this work consisted of the consideration of the parameters influencing the elastic properties using different micromechanics approaches and numerical techniques

Mechanical Homogenization of Transversely Isotropic CNT/GNP Reinforced Biocomposite for Wind Turbine Blades: Numerical and Analytical Study

One of the biggest problems facing the use of carbon nanotubes in reinforced composites is agglomeration within the matrix phase. This phenomenon—caused by Van der Waals forces—leads to dispersion problems and weakens the properties of the composites. This research presents a multi-stage homogenization approach used to investigate the influence of the aspect ratio, volume fraction, and agglomeration of the nanofillers on the effective mechanical properties of a polymer biocomposite containing randomly dispersed carbon nanotubes and graphene nanoplatelets. The first stage consisted in evaluating the properties of the reinforced polymers by the CNT/GNP. The second step consisted in combining the reinforced polymers with different natural and synthetic unidirectionally oriented fibers. It was found that agglomeration has a huge influence on the mechanical properties of the composite. The novelty of this work consisted of the consideration of the parameters influencing the elastic properties using different micromechanics approaches and numerical techniques

3D printing: rapid manufacturing of a new small-scale tidal turbine blade

International audienceThe 3D printing technology used for small tidal and wind turbines has great potential to change and overcome certain weaknesses in traditional manufacturing techniques. In rural areas and isolated communities, small turbine systems could be locally fabricated and assembled by using additive manufacturing machines and also can be employed to decrease residential energy consumption. The objective of the paper is to study the thermomechanical performance of 3D printing of a small-scale tidal turbine blade and their process using Digimat-AM because more research efforts are needed in this area. In this work, the tidal turbine blade is printed by using the selective laser sintering (SLS) method with polyamide 12 (PA12) and polyether ether ketone (PEEK) polymers reinforced by carbon beads (CB) and glass beads (GB). This research examines conceptual considerations of small tidal turbines including material properties and aerodynamic parameters. Once the finite element evaluation has been completed, the deflection, residual stresses, temperature distribution, and the deformed blade or warpage can be obtained. It is concluded that PA12-CB has warpage higher than PA12-GB by 3.78%, and PEEK-CB has warpage lower than PEEK-GB by 8.4%. Also, the warpage of PA12-CB is lower than PEEK-CB by 10.31%, and the warpage of PA12-GB is lower than PEEK-GB by 20.95%. Therefore, the lowest warpage is observed for PA12-GB. Finally, the results showed that 3D printing presents an excellent opportunity in the design and development of tidal energy systems in the future

Mechanical Properties of a Biocomposite Based on Carbon Nanotube and Graphene Nanoplatelet Reinforced Polymers :: Analytical and Numerical Study

International audienceBiocomposites based on thermoplastic polymers and natural fibers have recently been used in wind turbine blades, to replace non-biodegradable materials. In addition, carbon nanofillers, including carbon nanotubes (CNTs) and graphene nanoplatelets (GNPs), are being implemented to enhance the mechanical performance of composites. In this work, the Mori–Tanaka approach is used for homogenization of a polymer matrix reinforced by CNT and GNP nanofillers for the first homogenization, and then, for the second homogenization, the effective matrix was used with alfa and E-glass isotropic fibers. The objective is to study the influence of the volume fraction Vf and aspect ratio AR of nanofillers on the elastic properties of the composite. The inclusions are considered in a unidirectional and random orientation by using a computational method by Digimat-MF/FE and analytical approaches by Chamis, Hashin–Rosen and Halpin–Tsai. The results show that CNT- and GNP-reinforced nanocomposites have better performance than those without reinforcement. Additionally, by increasing the volume fraction and aspect ratio of nanofillers, Young’s modulus E increases and Poisson’s ratio ν decreases. In addition, the composites have enhanced mechanical characteristics in the longitudinal orientation for CNT- reinforced polymer and in the transversal orientation for GNP-reinforced polymer

Study of copper removal by modified biomaterials using the response surface methodology, DFT Calculation, and molecular dynamic simulation

International audienceCopper removal by adsorption from an aqueous solution was tested onto the Oyster Shells (OS) powder as an inexpensive adsorbent material. The effect of process parameters such as pH, initial pollutant concentration, adsorbent mass, and contact time on the copper removal in batch experiments conditions was investigated using an experimental design methodology to determine the optimal conditions for copper treatment. Adsorbent content, initial concentration of copper, pH, and contact time for maximum Cu(II) removal (82.58 %) were optimized and were found to be 2 g, 150 mg.l−1, 5.5, and 2.5 h, respectively. The adsorption equilibrium data followed the Langmuir isotherm model, whereas the pseudo-second-order equation was the best applicable kinetic model to describe the adsorption of Copper onto OS powder. The study concluded that the OS has potential application as an adsorbent to remove toxic heavy metals such as copper from industrial wastewater. Aside from experimental methods, theoretical methods such as DFT simulations, molecular dynamics simulations, and the radial distribution method were employed to uncover parameters regulating the effectiveness of the examined adsorbate