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Determination of interfacial fracture energy for 'pop-in' delaminations in a glass-epoxy system using the indentation method
摘要： The adhesion of coatings often controls the performance of the substrate-coating system. Certain engineering applications require an epoxy coating on a brittle substrate to protect and improve the performance of the substrate. Interfacial adhesion measurements of such systems provide a quantitative metric of that performance. Indentation experiments were performed to induce interfacial delaminations in a glass substrate-epoxy coating system. Delamination loads and radii were measured and applied to an analytical solution originally developed by Rosenfeld et al. (1990) to estimate the interfacial fracture energy of the substrate-coating adhesive bond. Results suggest an interfacial bond strength far exceeding that of similar previously studied glass-epoxy systems.
关键词： bonding,indentation,glass,coatings,epoxy,interfaces,fracture energy,adhesion
更新于2025-09-09 09:28:46
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[IEEE 2018 IEEE 7th World Conference on Photovoltaic Energy Conversion (WCPEC) (A Joint Conference of 45th IEEE PVSC, 28th PVSEC & 34th EU PVSEC) - Waikoloa Village, HI, USA (2018.6.10-2018.6.15)] 2018 IEEE 7th World Conference on Photovoltaic Energy Conversion (WCPEC) (A Joint Conference of 45th IEEE PVSC, 28th PVSEC & 34th EU PVSEC) - Fundamental Characterization of Anti-Soiling Coatings for PV Glass: Application of Small-Angle X-ray Scattering
摘要： When dust and other particulates accumulate on the surface of solar modules, the efficiency of these soiled modules is significantly reduced. Soiling is especially problematic in regions with little rain, where water resources for cleaning modules are scarce. To combat this issue, anti-soiling coatings, on the top-surface of solar modules, are beginning to enter the market. However, limited understanding of anti-soiling mechanisms and uncertainty in their durability has limited their deployment. Porous coatings are anticipated to discourage soiling because their rough surfaces reduce the strength and probability of dirt-to-coating bonds. However, the evolution of this morphology through soiling cycles is largely unknown. Here we present the use of small angle X-ray scattering (SAXS) to monitor the morphology of pristine and soiled, industry-sourced coatings. Initial soiling tests are performed using a standardized soil (AZ road dust) in the lab. This work demonstrates the effectiveness of SAXS in monitoring coating morphology despite the presence of soil surface layers. The capability of SAXS studies to be performed under various temperature, humidity, and soiling conditions sets it apart as a strong characterization tool for developing the understanding of functionality and degradation mechanisms of anti-soiling coatings for PV glass.
关键词： soiling,anti-soiling,materials forensics,small-angle X-ray scattering,anti-reflection,PV glass,coatings,self-cleaning
更新于2025-09-09 09:28:46
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Radiation induced luminescence properties of pure and Sn-doped 60ZnO.40P2O5 glass
摘要： We have investigated the optical properties and the ionising radiation induced luminescence of xSnO.(60?x)ZnO.40P2O5 (xSZP, x=0, 2·5 and 5) glasses prepared by a conventional melt-quenching method. In optical transmittance measurements, they exhibit 80–90% transparency from UV to visible wavelengths. The photoluminescence quantum yield of the 2.5SZP glass is 95%, with microsecond order decay constants, while that of the Sn-free glass is 3%, with a fast decay time of a few nanoseconds. The peak emission wavelength in scintillation spectra under x-ray irradiation is similar to that in photoluminescence, and appears at around 400 nm. The scintillation decay times of Sn-doped and Sn-free samples under x-ray exposure are a few μs and a few ns, respectively. The thermally stimulated luminescence glow curve was evaluated. For the Sn-doped sample, glow peaks were observed at 210 and 300°C, while the Sn-free sample showed a peak at 150°C. By conducting an initial rise method for trap analysis, the trap depth was found to be 5–10 meV. Optically stimulated luminescence was also examined, and a luminescence peak appeared at around 500 nm with 630 nm stimulation. Based on these results, we propose an energy level diagram of radiation induced luminescence in these glasses.
关键词： scintillation,photoluminescence,thermally stimulated luminescence,Sn-doped zinc phosphate glass,optically stimulated luminescence
更新于2025-09-09 09:28:46
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Ultrapure NIR-to-NIR Single Band Emission of β-PbF2: Yb3+/Tm3+ in Glass Ceramics
摘要： An ultrapure near infrared (NIR) emission entered at 800 nm upon 976 nm laser excitation (NIR-to-NIR) was observed in β-PbF2: Yb3+/Tm3+ glass ceramics (GCs). The ultrapure NIR-to-NIR single band emission originated from the 3H4 → 3H6 transition of Tm3+ with the ratio of NIR emission, and a blue band up to 9,633 was obtained. Through detailed analysis of the crystal structure and the energy transfer between Tm3+ and Yb3+, it is elucidated that the host lattice with low phonon energy cooperative with the energy mismatch results in a dramatic population of the 3H4 state as well as ultrapure NIR-to-NIR single band emission. Moreover, up-conversion (UC) emission properties and the decay lifetimes of β-PbF2: Yb3+/Tm3+ in GCs were explored thoroughly. The results illustrate that efficient cross relaxation (CR) processes between Tm3+ generate the energy redistribution in UC emission spectra, further concentrating energy to NIR emission. These two issues can be treated as crucial factors on ultrapure NIR-to-NIR single band emission in β-PbF2: Yb3+/Tm3+ in GCs. The ultrapure NIR-to-NIR single band emission through 976 nm laser excitation is advantageous for enhancing resolution and has potential application in bio-imaging fields.
关键词： Energy mismatch,Fluoride nanocrystal doped with Tm3+,Glass ceramics,Single band,Cross relaxation
更新于2025-09-09 09:28:46
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Effect of PbO–B2O3–BaO–SiO2 glass additive on dielectric properties of Ba0.5Sr0.5TiO3 ceramics for radio-frequency applications
摘要： In this work, the effects of PbO–B2O3–BaO–SiO2 (PBBS) glass addition (in increasing wt%) into Ba0.5Sr0.5TiO3 (BST0) ceramic on sintering, phase, and dielectric properties of BST0 are studied. The Ba0.5Sr0.5TiO3 (BST0) ceramic was synthesized by the conventional solid-state reaction method, and the PbO–B2O3–BaO–SiO2(PBBS) glass was formed by melting and quenching process. The PBBS glass with different weight percentages (3, 5, 8 and 10 wt%)is added to BST0 ceramic (BST3, BST5, BST8, and BST10, respectively) as a sintering aid to reduce the sintering temperature. Addition of glass helps in better sintering at lower temperatures with the presence of liquid phase at the respective sintering temperatures. The results of liquid phase-sintered ceramics are compared with the BST0 ceramic sintered at 1523 K. The BST10 with 10 wt% glass showed the lowest sintering temperature of 1148 K. Rietveld refinement analysis of BST0 ceramic confirmed the formation of single phase with cubic crystal structure. X-ray diffraction patterns of all liquid phase-sintered ceramics showed that the glass has minimal reaction with the BST0 ceramic and does not affect the crystal structure. Dielectric characterization was performed within the temperature range 20–450 K and frequency range 1 kHz to 1MHz. It is revealed that the transition temperature shifted with different weight percentage of glass addition. All the compositions exhibit the paraelectric phase at room temperature. Dielectric properties were also measured in the microwave frequency range 8.5–11 GHz at room temperature.BST10shows the stable and highest dielectric constant (average value of εr = 27) with lowest dielectric loss (tanδ = ~0.121). Fourier transform infrared (FTIR) and Raman spectroscopy confirmed the formation of desired compositions by detecting molecular vibrations and chemical bonding. The synthesized ceramic is a low-cost candidate and can have potential uses in the radio-frequency applications.
关键词： Dielectric properties,Glass,Sintering,Transition Temperature,Calcination
更新于2025-09-09 09:28:46
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On the efficient Te4+→Yb3+ cooperative energy transfer mechanism in tellurite glasses: A potential material for luminescent solar concentrators
摘要： Te4+/Yb3+ co-doped 80%TeO2-20%Li2O glasses (amounts in mol%) were prepared by the conventional melt-quenching method in an ambient atmosphere, in order to investigate their optical characteristics for application in solar cells. An efficient near-infrared down-conversion mechanism was observed in these samples, involving the emission of two near infrared photons (at around 978 nm) after the absorption of one photon in the ultraviolet-blue region. This effect occurred by means of a process of cooperative energy transfer (CET) from Te4+ to Yb3+ ions. The CET efficiency (h CET) was calculated from radiative transitions (lifetime) and also by a new method, developed in this work, based on rate equations quantifying the non-radiative transitions (thermal effect) involved in the system. The two methods showed very good agreement, with h CET between 82-100% obtained for the sample prepared using a higher Yb3+ concentration (4 mol%). The results suggested that these tellurite materials could have potential applications in improving the efficiency of silicon-based solar cells.
关键词： Te4+ ions,Thermal lens effect,Tellurite glass,Yb3+ ions,Down-conversion,Cooperative energy transfer
更新于2025-09-09 09:28:46
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Tuning magnetism in 0.25BaTiO3-0.75CoFe2O4 hetero-nanostructure to control ferroelectric polarization
摘要： In multiferroic composites, the strain-mediated magnetoelectric coupling is strongly dependent on the characteristics of interface between two (ferroelectric/ferromagnetic) mechanically coupled phases. In this paper, we have studied the magnetic ordering in 0.25BaTiO3-0.75CoFe2O4 (BTO-CFO) nanoparticles and the results are compared with pure CoFe2O4 (CFO) nanoparticles. The cubic spinel structure of CFO and tetragonal BTO is analyzed with X-ray diffraction pattern. The magnetic hysteresis measured at room temperature for both multiferroic BTO-CFO and pure CFO are quite different, that indicate magnetic ordering, which in BTO-CFO composite is changeable. Comparatively higher coercivity in pure CFO than BTO-CFO nanoparticles is observed at room temperature which suggested freezing out of thermal excitations and the onset of stable ferromagnetic ordering. The value of blocking temperature (corresponding to superparamagnetic state), TB is 385 K is observed in pure CFO and 355 K of BTO-CFO. However, the magnetic curve of zero field cooling magnetization is reasonably different than that observed in pure CFO, which is further studied with frequency dependent ac magnetic susceptibility measurement. It results into spin-canting and spin-glass states formation. The spin-glass transition temperature is calculated with both dynamical scaling and Vogel-Fulcher methods. The ferroelectric hysteresis is observed at room temperature is reasonably varied with applied magnetic field of 2, 4, 5, 6 kOe and the variation in the values of polarization and coercive field might be consistent with the observed magnetic hysteresis.
关键词： Multiferroic,Spin-glass,Magnetic ordering
更新于2025-09-09 09:28:46
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and above: Experiments and modeling in the optically-thick regime
摘要： This work presents the exploratory experimental results of a co-located solar receiver and thermal energy storage (TES) concept based on a pool of molten glass contained in a cavity, serving as solar receiver and TES medium simultaneously. Distinctive features of the system are the direct and volumetric absorption of solar radiation by the semi-transparent glass and a stationary TES medium. Only the charge cycle was studied, without a heat-removal system. Recycled soda-lime-silica (SLS) container glass of various colors was adopted as working medium in a setup tested at the ETH’s High Flux Solar Simulator (HFSS). A steady 3D heat transfer model of the experimental apparatus, which couples Monte-Carlo ray-tracing and CFD techniques, was developed and validated against the experimental results. The tests used the HFSS as the only energy source, with maximum radiative fluxes of 1.2 MWm?2 and power input of 1.5 kW directly absorbed by the glass, which reached measured temperatures of 1300 °C, while the maximum temperatures –as predicted by the model– exceeded 1500 °C. Such conditions were maintained for 5 to 10 h and no technical problems were encountered with the containment of the hot glass melt. These preliminary results demonstrate that silicate glasses are effective volumetric absorbers of solar radiation up to temperatures exceeding 1300 °C.
关键词： Concentrating Solar Power (CSP),Glass,Thermal Energy Storage (TES),GLASUNTES
更新于2025-09-09 09:28:46
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Gamma-Ray Dose Measurement with Radio-Photoluminescence Glass Dosimeter in Mixed Radiation Field for BNCT
摘要： Accelerator based neutron sources (ABNS) are being developed as the next generation neutron irradiation system for BNCT. From the ABNS, unnecessary gamma-rays will be generated by neutron capture reactions, as well as fast neutrons. To control the whole-body radiation dose to the patient, measurement of gamma-ray dose in the irradiation room is necessary. In this study, the objective is to establish a method to measure gamma-ray dose separately in a neutron/gamma mixed field by using RPL glass dosimeter. For this purpose, we proposed a lead filter method which uses a pair of RPL glasses with and without a lead filter outside. In order to realize this method, the basic characteristics of glass dosimeter was verified in the gamma-ray field, before adapting it in the mixture field. From the result of the experiment using the lead filter, the simulation result especially for the case with a lead filter overestimated the absorbed does obtained from measurement. We concluded that the reason of the discrepancy is caused by existence of gradient of the dose distribution in the glass, and the difference of sensitivity to low-energy photon between measurement and theory.
关键词： RPL glass dosimeter,BNCT,gamma-ray dose measurement,mixed radiation field,lead filter method
更新于2025-09-09 09:28:46
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ASAXS study of CaF <sub/>2</sub> nanoparticles embedded in a silicate glass matrix
摘要： The formation and growth of nanosized CaF2 crystallites by heat treatment of an oxyfluoride glass of composition 7.65Na2O–7.69K2O–10.58CaO–12.5CaF2–5.77Al2O3–55.8SiO2 (wt%) was investigated using anomalous small-angle X-ray scattering (ASAXS). A recently developed vacuum version of the hybrid pixel detector Pilatus 1M was used for the ASAXS measurements below the Ca K-edge of 4038 eV down to 3800 eV. ASAXS investigation allows the determination of structural parameters such as size and size distribution of nanoparticles and characterizes the spatial distribution of the resonant element, Ca. The method reveals quantitatively that the growing CaF2 crystallites are surrounded by a shell of lower electron density. This depletion shell of growing thickness hinders and finally limits the growth of CaF2 crystallites. Moreover, in samples that were annealed for 10 h and more, additional very small heterogeneities (1.6 nm diameter) were found.
关键词： silicate glass matrix,electron density,CaF2 nanoparticles,ASAXS,nanostructure
更新于2025-09-09 09:28:46