► A PV module must be preconditioned prior to obtain measurements under STC. ► The dark deactivation of a CdTe PV module occurs in 10min. ► A cooling system is used to reduce the temperature effect ...in a measurement. ► A part of the initial degradation of a CIS PV module can be recovered.
Photovoltaic modules based on thin film technology are gaining importance in the photovoltaic market, and module installers and plant owners have increasingly begun to request methods of performing module quality control. These modules pose additional problems for measuring power under standard test conditions (STC), beyond problems caused by the temperature of the module and the ambient variables. The main difficulty is that the modules’ power rates may vary depending both on the amount of time they have been exposed to the sun during recent hours and on their history of sunlight exposure. In order to assess the current state of the module, it is necessary to know its sunlight exposure history. Thus, an easily accomplishable testing method that ensures the repeatability of the measurements of the power generated is needed.
This paper examines different tests performed on commercial thin film PV modules of CIS, a-Si and CdTe technologies in order to find the best way to obtain measurements. A method for obtaining indoor measurements of these technologies that takes into account periods of sunlight exposure is proposed. Special attention is paid to CdTe as a fast growing technology in the market.
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•Seasonal Pmax varied on a-Si +5.9% (thermal annealing effect) and −5.7% (light soaking effect).•The total three-year performance ratio of poly-Si was 1% higher than a-Si and ...CdTe.•Instantaneous temperature effect on a-Si maximum power was negligible.•Air mass dependence of a-Si and CdTe were −11.22%/AM and −4%/AM, respectively.
Three grid connected photovoltaic systems based on different PV technologies (poly-Si, a-Si and CdTe), operating under the same conditions were analysed to determine their degradation and the variation in seasonal performance. In addition to the intrinsically different degradation of each technology through indoor tests at standard test condition (STC), a deeper analysis of the variables affecting the fluctuations of the performance was performed. The performance seasonal fluctuations resulting from the solar spectrum and module temperature was studied during a single year (December 2014 to December 2015). A notable solar air mass spectrum dependence (−11.22%/AM) of the generated power but scarcely detectable instantaneous temperature dependence was observed in the a-Si array. In contrast, the poly-Si array suffered the highest power decline with an elevating temperature (−0.56%/°C). The CdTe array exhibited a tempered interaction with the solar spectrum (−4%/AM) and temperature (−0.25%/°C). Finally, the significant maximum power difference between two months (April and September) due to the thermal annealing and light soaking effects in the a-Si array is confirmed, where the quantified variation of these two effects were 5.9% and −5.7%, respectively.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
This work presents the projection for future photovoltaic (PV) module waste mass in Spain to 2050. The possible effect of the Spanish PV installation boom occurred in the period 2007–2008 is ...investigated. The PV waste mass is assessed on the basis of cumulative PV capacity projections considering a 100% renewable Spanish scenario in 2050. The failure probability of the installed PV capacity is modeled by means of a Weibull distribution function. Four degradation scenarios are used to take into account different reliability levels of PV technology. The initial PV capacity projections are corrected by including the repowering needs of the PV installations to 2050. The obtained results suggest that repowering could mean around 40–47% of the annual PV power installed in Spain in 2050. From these data a cumulative PV waste mass of the order of 700,000 tonnes would be expected in 2050. In the period from 2020 to 2030, a cumulative PV waste mass around 100,000 tonnes would be obtained due to the end-of-life of PV modules installed in 2007–2008. This would mean that the Spanish PV recycling sector should be prepared to manage large amounts of PV waste mass earlier than other European countries. Nevertheless, a national PV recycling industry could suffer a period of waste scarcity after the repowering of the 2007–2008 PV plants would be finished. In 2050, this industry would recover around 75% of the raw materials required to manufacture the PV modules demand in Spain. The obtained results also suggest that the minimum recycling targets proposed in the Spanish Royal Decree on Wastes of Electric and Electronic Equipments (WEEE) should be revised to long-term.
•Repowering of Spanish PV plants could mean 40–50% of the PV power installed in 2050.•A cumulative PV waste mass of the order of 700,000 tonnes would be expected in 2050.•Large amounts of PV waste could arise in Spain earlier than other EU countries.•Irregular evolution of Spanish PV capacity could lead to a period of waste scarcity.•Minimum recycling targets in WEEE regulation could be oversized for PV waste.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
A conventional photovoltaic module has been prepared with the purpose of accessing its cells either individually or associated. Measurements of every cell and of the whole module have been performed ...in direct and reverse bias, with the objective of documenting the scattering in cell parameters, working point of the cells and shading effects. Several shading profiles have been tested, and the influence of the reverse characteristic of the shaded cell in module output is stressed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
In this work, synthesis of copper/reduced graphene oxide composites to increase the electrical conductivity of copper matrix has been carried out. Pure copper particles were mixed with 0.28 wt%, ...1.1 wt% and 2.5 wt% graphene oxide (GO) contents. Different reduction methods were chosen to synthetize the Cu/rGO composite material: chemical reduction with hydrazine, thermal treatment at 815 °C in argon atmosphere. Characterization of the Cu/rGO composite disks was carried out by optical microscopy, scanning electron microscopy, X-ray photoelectron spectroscopy and Raman spectroscopy. Vickers Hardness and the electrical conductivity measured by Van der Pauw method of the Cu/rGO composites were analyzed. All the Cu/rGO disks showed lower hardness values than the Cu matrix. Microstructure of Cu/rGO composites is dominated by the presence of pores where GO agglomerates are accumulated and whose distribution and magnitude depends on the weight percentage of GO and the reduction process. Porosity percentage and pore size of Cu/rGO disks increase with GO content. Combination of chemical reduction with thermal treatment provides the most homogeneous microstructures with the smallest pore size and porosity percentage. Combination of both reduction treatments promotes more pathways for carrier transport within the reduced graphene oxide network structure, expanding areas of long-range conjugated structures and, consequently, increasing the electrical conductivity in the rGO/copper composites. Our research evidences that the Cu/rGO composites after chemical and thermal reduction increases the electrical conductivity, independently on the GO content, with respect to the pure copper matrix.
•Effective chemical-thermal reduction of graphene oxide in copper matrix is achieved.•C/O ratio of 6.9 in Cu/rGO composites after reduction treatments is obtained.•Increased electrical conductivity in Cu/rGO due to long-range sp2 structures.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
► Chemical conversion treatment in HF slows down biodegradation of Mg materials. ► In cell culture medium, MgF
2 coating retards corrosion process for at least a week. ► Coated cast Mg and AZ31 are ...promising candidates for biodegradable implants.
Mg-based materials are especially attractive as biodegradable implants, although they degrade so fast in physiological media that corrosion protection is needed. In this work, biodegradation kinetics of powder metallurgy Mg, cast Mg and AZ31 alloy were evaluated by EIS measurements in cell culture medium (DMEM), which simulates closely the physiological media. To reduce their degradation rate, a chemical conversion treatment in HF was applied to form MgF
2 coatings. Results confirmed that this coating slows down the biodegradation rate, especially when formed on cast Mg and AZ31, retarding the corrosion process in the cell culture medium for at least a week.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Between 2010 and 2022, there has been a significant increase in photovoltaic (PV) solar energy installations, driven by factors such as cost reductions, technological advances, policy support and ...innovative financing approaches. However, this rapid growth has created a significant challenge in the form of increased PV waste generation, coinciding with global commitments to achieve carbon neutrality by 2050. The potential for reuse of decommissioned PV modules represents an environmentally sustainable way forward that requires a comprehensive assessment of technical, economic, environmental and regulatory considerations. This study focuses on evaluating the impact of defects in partially repaired PV modules from Spanish installations on their power output and efficiency, with the aim of developing strategies to increase reuse and reduce environmental impact. The research focuses on 23 crystalline silicon modules and uses established techniques to evaluate their operational condition, detect defects and assess potential safety risks. Among the defects observed, moisture-induced degradation (MID) emerges as the most prevalent, followed by cracked cells and disconnected areas in cells across different technologies. Notably, despite the presence of defects, approximately 87 % of these modules have a power loss of less than 20 %.
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•Reusing partially repaired PV modules is an environmentally sustainable solution.•Moisture-induced degradation (MID) is the most prevalent failure.•Despite defects, 87% of the tested modules exhibited a power loss of under 20%.•Characterising modules ensure long-term viability and PV circularity.•Regulations are necessary to stimulate the second-hand modules market.
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•Complete restoration of graphene structure is not achieved by electrochemical methods.•Reduction of GO on CoCr resulted in residual CO and CO groups in graphene network.•Presence of ...oxy-functional groups caused structural disorder in graphene network.•Reduction at −2.1 V reveals Raman shifts due to CoCr in ErGO/CoCr Raman spectra.
In the present work, the characterization of Electrochemically Reduced Graphene Oxide (ErGO) films on a biomedical grade CoCr alloy has been performed. The direct electrodeposition process was carried out by means of two electrochemical techniques: chronoamperometry and cyclic voltammetry experiments, both taking into account the influence of oxygen in the solution. Characterization of the resulting ErGO films on CoCr alloys was carried out by SEM, AFM, Raman spectroscopy and XPS. Both electrochemical reduction procedures led to the deposition of graphene-based films on the CoCr surfaces after the partial removal of the oxygenated functional groups present in the graphene network of the starting material. The deconvolution of the XPS high-resolution C1s and O1s spectra mainly showed Csp2 bonding and the presence of CO and CO residual groups covering the CoCr surface. Moreover, the ErGO films that were stacked on the CoCr surfaces exhibited non-uniform thickness reaching values corresponding to the presence of 80 layers of the graphene material. In addition, Raman spectroscopy revealed a certain structural disorder in the ErGO films deposited by means of the different electrochemical techniques investigated. This fact was more evident on the film from the chronoamperometric experiments, as the fastest electrochemical reduction rate provided by the application of a high reduction potential (−2.1 Vvs. Ag/AgCl) could induce the development of defects in the resulting film, so the peaks corresponding to the CoCr substrate could be observed.
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The optimum sizing ratio of the photovoltaic (PV) array capacity, compared to the nominal inverter input capacity, was determined in grid-connected PV (GCPV) systems from two points of view: ...energetic and economic. The optimum ratio was determined by both empirical and analytical approaches, and based on two PV arrays connected to their inverters, plus three simulated inverters.
The flatness of the optimum-energy region due to the inverter characteristics was decreased when economic factors were taken into account. The energetic and economic optimum sizing intervals were defined as the sizing regions causing less than 1% losses from their corresponding optimum points. Subsequently, a compound optimum sizing interval was proposed to maximise the energy injected to the grid and minimise economic costs simultaneously. The results showed that the GCPV system with lower specific DC power generation (kWDC/kWp) and inverter/module cost ratio presented a wider interval (1.12–1.25) than the interval (1.17–1.19) of the system with higher specific DC power generation and cost ratio, for all the analysed inverters. Finally, the optimum sizing ratio was completed by considering a PV module degradation rate of 1%/year, which resulted in a 10% increase in the optimum sizing ratio for a 20-year lifetime.
•An optimum sizing ratio interval benefiting in both energy and economy is proposed.•The clipping effect of undersized inverter is interpreted.•An accurate inverter efficiency model is used and assessed.•Inverter characteristics affected AC output more than sizing ratio.•1% degradation rate and 20-year lifetime lead to a 10% rise of optimum sizing ratio.
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Bovine in vitro endometrial models that resemble tissue function in vivo are needed to study infertility, long-term uterine alterations induced by pathogens and impact of endocrine disruptor ...chemicals on reproductive function and other reproductive system complications that cause high economic losses in livestock species. The present study aimed to generate an innovative, reproducible, and functional 3D scaffold-based model of the bovine endometrium structurally robust for long term-culture. We developed a multicellular model containing both endometrial epithelial and stromal cells. Epithelial cells organized to form a luminal-like epithelial layer on the surface of the scaffold. Stromal cells produced their own extracellular matrix forming a stable subepithelial compartment that physiologically resembles the normal endometrium. Both cell types released prostaglandin E
2
and prostaglandin F
2α
following a treatment with oxytocin and arachidonic acid. Additionally signal pathways mediating oxytocin and arachidonic acid stimulation of prostaglandin synthesis were analyzed by real time PCR (RT-PCR).
Oxytocin receptor
(
OXTR
),
prostaglandin E
2
receptor 2
(
EP2
),
prostaglandin E
2
receptor 4
(
EP4
),
prostaglandin F receptor
(
PTGFR
),
prostaglandin E synthase
(
PTGES
), PGF-synthase (
PGFS
) and prostaglandin-endoperoxide synthase 2 (
COX-2
) expression was detected in both control and treatment groups, however, only significant changes in abundance of
OXTR
mRNA transcripts were found. The results obtained by this study are a step forward in bovine in vitro culture technology. This 3D scaffold-based model provides a platform to study regulatory mechanisms involved in endometrial physiology and can set the basis for a broader tool for designing and testing novel therapeutic strategies for recurrent uterine pathologies.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
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