Thermal treatment of waste photovoltaic module for recovery and recycling: Experimental assessment of the presence of metals in the gas emissions and in the ashes

The rapid expansion of the photovoltaic (PV) module market in the last years will determine in the near future a remarkable growth of corresponding waste. Then, the hazardous materials contained in the modules, such as Cd, Pb and Cr, could be released in the environment if the waste panels will not be handled adequately. Recycling processes of silicon crystalline panels, finalized to separate PV cells from the glass, involve the removal of the EVA (Ethylene Vinyl Acetate) layer through different methods, as the thermal treatment. During this treatment, some hazardous components can be released due to thermal degradation process. In this paper the metals released in the gas emissions and in the ashes due to the thermal treatment of modules were evaluated. For this purpose, three samples of crystalline panels were heated in furnace up to 600 °C and the complete degradation of the EVA was obtained. A mass balance between the sample and its components, before and after treatment, was performed in order to assess the weight loss percentage. Finally, after thermal treatment a qualitative analysis on the separated PV cell surface was performed by SEM-EDS (Scanning Electron Microscope equipped with Energy Dispersive Spectrometer).     

A Constitutive Equation of Thermoelasticity for Solid Materials

A new constitutive equation of thermoelasticity for crystals is presented based on the interatomic potential and solid mechanics at finite temperature. Using the new constitutive equation, the calculations for crystal copper and graphene are carried out under different loading paths at different temperatures. The calculated results are in good agreement with those of the previous thermoelasticity constitutive equation based on quantum mechanics, which clearly indicates that our new constitutive equation of thermoelasticity is correct. A lot of comparisons also show that the present theory is more concise and efficient than the previous thermal stress theory in the practical application.     

Hygrothermal deformation of orthotropic nanoplates based on the state-space concept

This paper deals with the investigation of the effect of hygrothermal conditions on the bending of nanoplates using Levy type solution model employing the state-space concept. The nanoplates are assumed to be subjected to a hygrothermal environment. The two-unknown function plate theory is used to derive the governing differential equations on the basis of Eringen's nonlocal elasticity theory. The governing equations contain the small scale effect as well as hygrothermal and mechanical effects. These equations are converted into a set of first-order linear ordinary differential equations with constant coefficients. Analytical solution of bending response for nanoplates under combinations of simply supported, clamped and free boundary conditions is obtained. Comparison of the results with those being in the open literature is made. The influences played by small scale parameter, temperature rise, the degree of moisture concentration, boundary conditions, plate aspect ratio and side-to-thickness ratio are studied.     

Computational analysis of thin coating layer failure using a cohesive model and gradient plasticity

Thermal barrier coatings (TBC) are widely used to prevent transient high temperature attack and allow components high durability. Due to strong inhomogeneous material properties the TBC failure often initiates near the interface between the brittle oxide layer and the ductile substrate. A reliable prediction of the TBC failure requires detailed information about the crack tip field and the consequent fracture criteria. In the present paper both cohesive model and gradient plasticity are used to simulate the failure process and to study interdependence of the interface stress distribution with the specific fracture energies. Computations confirm that combination of the two models is able to simulate different failure mechanisms in the TBC system. The computational model has the potential to give a realistic prediction of the crack propagation process.     

Spectral properties of diesel fuel droplets

Absorption spectra of several types of diesel fuel are studied experimentally. Index of refraction of these fuels is calculated using subtractive Kramers-Krönig analysis. The ageing process of fuels is simulated by prolonged boiling. Radiative properties of diesel fuel droplets are calculated using the Mie theory and a simplified approach, based on approximations of absorption and scattering efficiency factors. It is pointed out that the accuracy of the simplified approach is sufficient for practical applications in the visible and infrared ranges, for various types of diesel fuel, and for droplet radii in the range from 5 to 50 μm. The monodisperse approximation is shown to be applicable for the analysis of infrared radiative properties of realistic polydisperse diesel fuel sprays.     

正确选用热力管网保温材料的几个问题

介绍了做好热力管网保温应具备的有关知识和数据，以及宝钢蒸汽主干管网在采用四种保温材料下的经济保温层厚度和相对的节能效益，认为目前适于宝钢公司热源温度在６００℃以下较好的保温材料有新型矿渣棉制品和泡沫石棉板。     

Improving Wear Resistance of the Ni-base Thermal Spray-Welding Coating Using Rare Earths

ＩｍｐｒｏｖｉｎｇＷｅａｒＲｅｓｉｓｔａｎｃｅｏｆｔｈｅＮｉｂａｓｅＴｈｅｒｍａｌＳｐｒａｙＷｅｌｄｉｎｇＣｏａｔｉｎｇＵｓｉｎｇＲａｒｅＥａｒｔｈｓＺｈａｉＧｕａｎｇｊｉｅ（翟光杰）（ＩｎｓｔｉｔｕｔｅｏｆＰｈｙｓｉｃｓ，ＡｃａｄｅｍｉｃａＳｉ...     

功率电子器件用AlN陶瓷基板的研制

阐述了AlN陶瓷的烧结原理 ,分析了烧结工艺参数对大面积AlN基板性能的影响 ,成功研制出了高热导率(190W /m·K)、大面积 (14 0mm× 90mm)、翘曲度为 2 0 μm/5 0mm的AlN陶瓷基板。     

The Clausius inequality corrected for heat transfer involving radiation

The objective of this paper is to prove that the Clausius inequality must be re-stated to have general applicability for heat transfer involving radiative fluxes. The integrand (đQ/T) of the Clausius expression applies to heat conduction and convection, but does not hold for most radiative transfer scenarios, with the exception of reversible infinitesimal net blackbody radiation transfer. In other cases involving radiative transfer, the equality holds for a cycle even though irreversible heat addition by radiative transfer occurs. This is without the erroneous presumption of entropy destruction anywhere in the cycle. Thus, the Clausius inequality indicates reversibility for a cycle that includes an irreversible process. Further, in some radiative cases the quantity đQ/T, where T is the boundary temperature, is not the entropy transfer at the system boundary, and in fact, primarily represents entropy production within the system. It is also clear that in another case considered, the quantity đQ/T had no physical meaning whatsoever. Consequently, the Clausius expression has been re-stated so that it is applicable to cycles with processes involving any form of heat transfer. A new integrand (đQ_cc/T + đS_Net,Rad) is presented, allowing the Clausius inequality to generally apply to all heat transfer scenarios. The work in this paper emphasizes the need to re-state other fundamental equations allowing applicability to all heat transfer processes, and draws attention to the unique character of radiative entropy calculations.     

Thermal-lens and photo-acoustic methods for the determination of SiC thermal properties

In this paper we report the use of photothermal techniques such as Thermal lens (TL) spectrometry, Photoacoustic and heat capacity, ρc_p, to determine the thermo-optical parameters, such as thermal conductivity (K), thermal diffusivity (D), specific heat (c_p) and the optical path dependence with temperature (ds/dT), of an undoped polycrystalline 3C-SiC. To our knowledge, this is the first time that Thermal lens technique is used for wide band-gap systems. Results obtained for the polycrystalline sample with TL technique indicates that ds/dT is negative at room temperature. Moreover, the obtained values of thermal diffusivity and thermal conductivity are in good agreement with that found in the literature, indicating that the phototermal techniques can be used to obtain the referred parameters in circumstances where other techniques cannot be used, for example, in harsh environments.