High Irradiance Conditions Research Articles

Experimental comparison between various fitting approaches based on RMSE minimization for photovoltaic module parametric identification

One solution for online condition monitoring of photovoltaic (PV) modules is to identify single-diode model parameter values from measured current–voltage (I–V) curves. By this way, use of expensive thermal cameras and radiometric sensors utilized in traditional monitoring methods can be avoided. Unfortunately, most of the parameter identification methods require measurements of the operating conditions, i.e., irradiance and temperature. This article proposes a novel procedure for identification of the single-diode model parameter values along with the operating irradiance and temperature values from measured I–V curves without needing any other measurement. The only inputs of the proposed procedure are the I–V curve measurements at the actual operating conditions together with the parameter values of the module model in standard test conditions. The proposed procedure is experimentally validated using I–V curves of three PV module types measured from two different locations. Both the whole I–V curves or only a part of them, in a limited voltage range, are considered. Moreover, I–V curve measurements with an emulated increase of the series resistance are used to demonstrate the correctness of the identified series resistance values. It is shown that the procedure identifies the operating irradiance and temperature with high accuracy even during sharp irradiance transitions and low irradiance conditions and identifies series and shunt resistances very reliably under nearly constant high irradiance conditions. Moreover, for the first time, a comprehensive comparison of various fitting approaches based on root-mean-square error (RMSE) minimization, including two novel approaches, is presented. The results show that the different fitting approaches based on RMSE minimization affect the accuracy of the parameters identification in a different way, this meaning that the used fitting approach is a factor that should be considered when implementing model parameter identification by curve fitting.

Assessing the Hybridization of an Existing Geothermal Plant by Coupling a CSP System for Increasing Power Generation

Concentrated Solar Power (CSP) and geothermal energy systems are outlined as two of the most promising technologies for sustainable and reliable electricity generation. Several studies in the technical literature have pointed out that the hybridization of solar and geothermal energy sources could lead to a reduction of the levelized cost of energy (LCOE) of geothermal systems, as well as improving the capacity factor of CSP systems. However, the technical literature shows that the integration of solar thermal collectors does not present a positive impact in all scenarios analyzed. The present study aims to further analyze the competitiveness of the hybridization of solar and geothermal systems under high irradiation conditions such as those observed in the Andean region in northern Chile. The evaluation was carried out by coupling a thermodynamic model in Engineering Equation Solver (EES) with a solar thermal model in the System Advisor Model (SAM). The assessment considers the configuration of an existing geothermal plant, considering the design constraints associated with the actual operating conditions of the plant. The analysis is based on an energy and exergy assessment, allowing us to identify the efficiency of the subsystems introduced for the hybridization and assess the competitiveness of the hybrid schemes by an economic assessment in terms of the LCOE. The results show that the hybrid schemes allow a reduction of the LCOE of a geothermal stand-alone plant by about 10 USD/MWh, increasing the competitiveness of the geothermal system. However, a large variation on such a reduction is observed depending on the size of the solar field and the storage tank of the solar system.

Desert label development for improved reliability and durability of photovoltaic modules in harsh desert conditions

We present strong arguments and experimental findings for the definition of a photovoltaic module accelerated ageing procedure for high irradiance and desert conditions to create a Desert Label for the particular Atacama Desert climatic conditions. A special focus on high ultraviolet solar radiation dosage in combination with either damp heat, salt mist or aggressive thermal cycling are presented. Indoor experimental results, strengthened by outdoor monitoring of sister mini-modules at the Atacama Desert, allowed selecting the appropriate ageing tests while exploring the reliability and durability of a wide range of module configurations, including various typical encapsulants, high efficiency cell technologies and module designs, for industrial applications.

Chloroplast protease/chaperone AtDeg2 holds γ<sub>1</sub> subunit of ATP synthase in an unaggregated state under high irradiance conditions in Arabidopsis thaliana

Little data on the role played in vivo by chloroplast protein AtDeg2 as a chaperone is available. Therefore, we sought for chloroplast proteins protected from high irradiance-induced interprotein aggregation via disulphide bridges by AtDeg2 acting as a holdase. To reach this goal, we performed analyses which involved comparative diagonal electrophoreses of lysates of chloroplasts isolated from wild type (WT) plants and transgenic plants 35S:AtDEG2ΔPDZ1-GFP which expressed AtDeg2 lacking its chaperone activity but retaining the protease activity. The results of the analyses indicate that AtDeg2 acting as a holdase prevents a single chloroplast protein, i.e., the γ1 subunit of ATP synthase from long-term high irradiance-induced homodimerization mediated by disuplhide bridges and this allows us to better understand a complexity of physiological significance of AtDeg2 - the chloroplast protein of dual protease/chaperone activity.

Fatty acids in microalgae and cyanobacteria in a changing world: Contrasting temperate and cold environments

Under the present changing climate conditions and the observed temperature increase, it is of high importance to understand its effects on aquatic microbial life, and organisms’ adaptations at the biochemical level. To adjust to temperature or salinity stress and avoid cell damage, organisms alter their degree of fatty acids (FAs) saturation. Thus, temperature is expected to have strong effects on both the quantity and quality of FAs in aquatic microorganisms. Here we review some recent findings about FAs sensitivity to climate change in contrasting environments. Overall, heat waves may induce changes in the relative abundance of polyunsaturated FAs (PUFA). However, the impact of the exposure to warming waters is different in temperate and polar environments. In cold marine waters, high concentration of omega-3 (ω3) FAs such as eicosapentaenoic acid (EPA) is promoted due to the activation of the desaturase enzyme. In this way, cells have enough energy to produce or activate antioxidant protection mechanisms and avoid oxidative stress due to heat waves. Contrastingly, under high irradiance and heat wave conditions in temperate environments, photosystems’ protection is achieved by decreasing EPA concentration due to desaturase sensitivity. Essential FAs are transferred in aquatic food webs. Therefore, any alteration in the production of essential FAs by phytoplankton (the main source of ω3) due to climate warming can be transferred to higher trophic levels, with cascading effects for the entire aquatic ecosystem.

HST/WFC3 Complete Phase-resolved Spectroscopy of White-dwarf-brown-dwarf Binaries WD 0137 and EPIC 2122

Abstract Brown dwarfs in close-in orbits around white dwarfs offer an excellent opportunity to investigate properties of fast-rotating, tidally locked, and highly irradiated atmospheres. We present Hubble Space Telescope Wide Field Camera 3 G141 phase-resolved observations of two brown-dwarf-white-dwarf binaries: WD 0137-349 and EPIC 212235321. Their 1.1–1.7 μm phase curves demonstrate rotational modulations with semi-amplitudes of 5.27% ± 0.02% and 29.1% ± 0.1%; both can be fit well by multi-order Fourier series models. The high-order Fourier components have the same phase as the first-order and are likely caused by hot spots located at the substellar points, suggesting inefficient day/night heat transfer. Both brown dwarfs’ phase-resolved spectra can be accurately represented by linear combinations of their respective day- and nightside spectra. Fitting the irradiated brown dwarf model grids to the dayside spectra require a filling factor of ∼50%, further supporting a hot spot dominating the dayside emission. The nightside spectrum of WD 0137-349B is fit reasonably well by non-irradiated substellar models, and the one of EPIC 21223521B can be approximated by a Planck function. We find strong spectral variations in the brown dwarfs’ day/night flux and brightness temperature contrasts, highlighting the limitations of band-integrated measurements in probing heat transfer in irradiated objects. On the color–magnitude diagram, WD 0137-349B evolves along a cloudless model track connecting the early-L and mid-T spectral types, suggesting that clouds and disequilibrium chemistry have a negligible effect on this object. A full interpretation of these high-quality phase-resolved spectra calls for new models that couple atmospheric circulation and radiative transfer under high-irradiation conditions.

A highly consistent and proficient class of multiport dc-dc converter based sustainable energy sources

ThePhotovoltaicsystem(PV) systems are reliable Renewable Energy Sources (RES) because to their efficiency under high irradiation conditions, low maintenance, and low pollution. Effective processes generate steady power. This new programme determines the dynamic performance of this technology's application to conduct a thorough feasibility utility grid is determined under different operational circumstances. However, integrating renewable energy into the alternating current system has challenges including voltage increases, synchronisation, and protection. With the DCDC converter, the power distribution system will be more reliable. The RES voltage level and storage needed by the static power DCDC converter must be maintained to preserve grid synchronisation. Because static converters are simple, they need a separate converter for stabilisation, increasing the circuit size. Compact size, centralised control, and energyefficient energy management are important features of Multiport Converters (MPC). The microgrid needs a backup battery to offset the intermittent nature of renewable energy sources. To ensure safety, isolation between the source and the load is required. Storage devices need a twoway power channel. An independent multiport converter is needed for the connected operation of the battery equipment and the utilisation of various renewable energy sources. The benefits of higher power density and separation of the nonisolation circuit allow for a smaller total circuit size. This paper summarises the multiport DCDC converter design for RES harvesting in a DC microgrid and makes research suggestions.

One task of routing jobs in high radiation conditions

The problem of sequential bypass of megalopolises is investigated, focused on the problem of dismantling a system of radiation hazardous objects under constraints in the form of precedence conditions. The radiation impact on the performers is assessed by the doses received during movements and during the performance of dismantling works. The route problem of minimizing the dose load of workers carrying out dismantling in one or another sequence of operations is considered. The procedure for constructing an optimal solution using a variant of dynamic programming is investigated. On this basis, an algorithm is built, implemented on a PC. Examples of the numerical solution of a model problem for the minimum dose load are given.

A new mixed hardening methodology applied to a 28 nm FDSOI 32-bits DSP subjected to gamma radiation

This work presents the performance degradation of a 32-bit DSP fabricated with 28 nm FDSOI technology subjected to different levels of gamma radiation. A new mixed hardening methodology based on electrical compensation and thermal regeneration is applied to the irradiated devices to recover the degraded electrical characteristics induced by the total ionizing dose. The application of this new methodology seeks to extend the lifetime of FDSOI integrated circuits under high radiation conditions while keeping good reliability.

Analysis of microgrid integrated Photovoltaic (PV) Powered Electric Vehicle Charging Stations (EVCS) under different solar irradiation conditions in India: A way towards sustainable development and growth

The depleting fossil fuel and growing environmental concern have opened the doors for clean and green energy development using renewable energy sources. Also, the growing oil demand and carbon emissions have created a huge scope for Electric Vehicle (EV) usage across the world which has resulted in blooming EV market. Photovoltaic (PV) powered EV charging can substantially reduce the carbon foot prints when compared to the conventional utility grid based EV charging. The amalgamation of solar power and EV charging is one of the best methods in sustainable development for EV market. Recent statistics suggest that usage of EVs in different cities in India has proliferated and the development of the charging infrastructure is a big challenge for the densely populated country. Firstly, theoretical demand model and stochastic model for EV traffic and resource utilization pattern is developed. Secondly, the optimal configuration and techno-economic assessment of Solar powered EV Charging Station (EVCS) in microgrid is analyzed for four different Indian cities (Shillong, Bengaluru, Jaipur and Kashmir) with varied solar radiation conditions. Lastly, the environment benefits of solar PV powered EVCS are assessed and analyzed. The results demonstrate that the optimal configuration and investment efficiency in each urban area is greatly affected by the solar irradiation and feed-in-tariff (FIT) price of rooftop solar power. Kashmir with high solar irradiation conditions can invest in the solar EVCS compared to the other cities.

Performance evaluation of monocrystalline and polycrystalline silicon solar photovoltaic modules under low and high irradiance conditions in Kumasi, Ghana


 
 
 One of the biggest drawbacks of photovoltaic (PV) for many applications is the uncertainty in the energy output due to losses attributed to efficiency loss at low irradiance levels. In this study, the electrical performance of as received monocrystalline silicon (mono-c-Si) and polycrystalline silicon (poly-c-Si) PV modules were evaluated at high and low irradiance conditions in Kumasi, Ghana using I-V Tracer. The low irradiance level of 200W/m2 was achieved by covering the surface of the PV modules with a calibrated mesh screen. Maximum output power (Pmax) of 87.9 W and 136.7 W were recorded for the mono-c-Si and poly-c-Si modules at high irradiance respectively. The corresponding average values at low irradiance were 8.29 W and 12.13 W representing percentage reductions of 90.57% and 91.60% respectively for the two technologies. These results indicate that when irradiance drops to 200 W/m2 and below, the PV modules generate around only 10% of their nominal output power. This has implications for the number of modules that are required for installation in areas that experience many hours of low irradiance. Efficiency reductions of 64.4% and 59.01% for the mono-c-Si and poly-c-Si modules respectively at low irradiance is reported. The results also indicate that the mono-c-Si is affected more by light induced degradation effect than the poly-c-Si module after a few hours of exposure to the natural light. The novelty of this work is that knowledge of the performance at low irradiance will enable designers determine the number of modules required during the sizing of PV plants.
 
 

High-Performance and Radiation-Hardened Solution-Processed ZrLaO Gate Dielectrics for Large-Area Applications.

Radiation hardness is important for electronics operating in harsh radiation environments such as outer space and nuclear energy industries. In this work, radiation-hardened solution-processed ZrLaO thin films are demonstrated. The radiation effects on solution-processed ZrLaO thin films and InOx/ZrLaO thin-film transistors (TFTs) were systemically investigated. The Zr0.9La0.1Oy thin films demonstrated excellent radiation hardness with negligible roughness, composition, electrical property, and bias-stress stability degradation after radiation exposure. The metal-oxide-semiconductor capacitors (MOSCAPs) based on Zr0.9La0.1Oy gate dielectrics exhibited an ultralow flat band-voltage (VFB) sensitivity of 0.11 mV/krad and 0.19 mV/krad under low dose and high dose gamma irradiation conditions, respectively. The low dose condition had a 103 krad (SiO2) total dose and a 0.12 rad/s low dose rate, whereas the high dose condition had a 580 krad total dose and a 278 rad/s high dose rate. Furthermore, InOx/Zr0.9La0.1Oy thin-film transistors (TFTs) exhibited a large Ion/Ioff of 2 × 106, a small subthreshold swing (SS) of 0.11 V/dec, a small interface trap density (Dit) of 1 × 1012 cm-2, and a 0.16 V threshold shift (ΔVTH) under 3600 s positive bias-stress (PBS). InOx/Zr0.9La0.1Oy TFT-based resistor-loaded inverters demonstrated complete swing behavior, a static output gain of 13.3 under 4 V VDD, and an ∼9% radiation-induced degradation. Through separate investigation of the radiation-induced degradation on the semiconductor layer and dielectric layer of TFTs, it was found that radiation exposure mainly generated oxygen vacancies (Vo) and increased electron concentration among gate oxide. Nevertheless, the radiation-induced TFT instability was mainly related to the semiconductor layer degradation, which could be possibly suppressed by back-channel passivation. The demonstrated results indicate that solution-processed ZrLaO is a high-potential candidate for large-area electronics and circuits applied in harsh radiation environments. In addition, the detailed investigation of radiation-induced degradation on solution-processed high-k dielectrics in this work provided clear inspiration for developing novel flexible rad-hard dielectrics.

Study on Shell Mode Vibration Characteristics of Reactor Core Barrel Based on Analysis of Pressure Vessel Vibration Signal

The vibration state of reactor core barrel is directly related to the safe operation of the core. However, the barrel is under high temperature and high radiation conditions, so it is impossible to measure the barrel vibration by a sensor directly installed on the barrel. In this paper, the accelerometer installed on the pressure vessel is used to indirectly monitor the barrel vibration. The coherence spectrum, auto-power spectrum and cross-power spectrum of vibration signal of pressure vessel with multiple nuclear units are analyzed to provide the shell mode vibration frequency and amplitude of the barrel. As shown by comparison, the analysis results approximate to the measured values from the test of Qinshan NPP Phase II Unit 1. The study results show that the shell mode vibration characteristics of the core barrel can be effectively identified by the monitoring and analysis of the pressure vessel vibration signals, which provides a foundation for the evaluation of the core barrel conditions.

Multi-scale fracture probability analysis of tungsten monoblocks under fusion conditions

Plasma facing components inside future nuclear fusion reactors are subjected to a high heat load and intense irradiation conditions. Using advanced computational material models, several problems can be solved that reflect tungsten monoblocks under fusion relevant loading scenarios. This allows for the identification of the conditions under which material failure is probable. The material model and parameters are identified such that the mechanical behaviour is in accordance with the homogenized behaviour of a previously developed crystal plasticity model on the microscopic scale. The heterogeneous stress field that follows is analysed in order to assess the probability of material failure, which is typically reflected by unstable crack propagation. Since fracture is an inherently multi-scale problem, critical regions are analysed in detail by means of a representative volume element. The resulting analysis reveals that in case the stress relaxation in the monoblock under the applied static heat load is complete, the probability of unstable crack propagation can reach values close to 35%. Finally, the impact of prolonged neutron irradiation is simulated by means of a cluster dynamics model. Although irradiation drastically increases the brittleness of tungsten, its impact on the overall monoblock performance remains limited. • The performance of tungsten monoblocks under fusion conditions is investigated. • Failure is predicted by application of the weakest-link theory on two length scales. • Stress relaxation increases the risk of failure upon shut down of the heat source. • The impact of neutron irradiation on the failure probability is shown to be limited.

Charge transport in single crystal CVD diamond studied at high temperatures

The capability of single crystal diamonds to maintain their unique electronic properties even at high temperatures is, in particular, relevant for its applications as a radiation detector. In order to explore characteristics of charge transport at high temperatures (up to 450 ∘C), diamond was exposed to MeV energy ions, both, to induce radiation damage and to probe subsequent influence on detector’s properties. Dependence of mobility-lifetime product with temperature has been obtained for electrons and holes. For holes, mu-tau displays a linear degradation with rising temperature, while for electrons, change with temperature is less evident. Furthermore, deep trapping levels induced in the material by radiation damage, were studied through time-resolved charge signals. Detrapping time was extracted from this data. Hole trap level, with the activation energy of 0.53 ± 0.01 eV has been detected in the regions of the diamond detector previously irradiated by 5 MeV damaging proton beam, but not in the pristine regions. This indicates that the trap was formed due to defect induction during radiation damage exposure. Activation of this deep level is important for charge transport performance in diamond detectors operating at high temperatures and high radiation conditions.

Study of aerosol optical properties at two urban areas in the north of Vietnam with the implication for biomass burning impacts.

The spatiotemporal distribution and characterization of aerosol optical properties in the north of Vietnam were investigated extensively using the long-term measurements obtained from Moderate Resolution Imaging Spectroradiometer (MODIS) (from 2010 to 2019) and two Aerosol Robotic Network (AERONET) stations (Nghia Do, Hanoi City, from 2010 to 2019 and Son La from 2012 to 2019) located in fast-developing urban areas. This study also analyzed the tendency of AOD over different wavelengths as well as the influences of meteorological parameters and boundary layer height (BLH) on AOD and Ångström exponent (AE). The annual mean AOD500 at Nghia Do and Son La stations were 0.81 and 0.78, respectively. Our results revealed the existence of particles emitted from anthropogenic activities in Hanoi and Son La with the dominance of fine particles (more than 90% of the AE440-870 were larger than 1). Besides, a high percentage of AE440-870 larger than or approximately 1.5 during the dry and transition months in Son La indicated the existence of biomass-burning aerosol particles due to forest fires and burning of agriculture residuals. The classification results for aerosol types showed the presence of both biomass burning and urban/industrial aerosol types at Nghia Do and Son La sites. Among the investigated meteorological parameters, surface solar radiation expressed a significant correlation with AE440-870 in all three seasons at the two sites due to the secondary formation of fine particles induced by the high solar radiation condition. The impacts of meteorological parameters and BLH on AOD were not observed simultaneously during three seasons at Nghia Do and Son La stations.

Overirradiance effect on the electrical performance of photovoltaic systems of different inverter sizing factors

The optimization of the installation characteristics of photovoltaic (PV) generators guarantee greater generation of electric energy and a better distribution of solar irradiation of the PV modules; on the other hand, to determine the sizing factor- SFI, one must take into account the saturation losses of the AC output during conditions of high irradiance and overheating of the inverters. Based on the behavior of the measured solar irradiance, there are several rapid oscillations, and over the days, most of the measured curves are superior to the clear sky model, caused by a transient effect of the atmospheric boundary layer. Two photovoltaics systems–SFCR, were analyzed using the same model and inverter power but with a different inverter design factor. The SFCR were installed in southern Brazil 30 km apart. According to the inverter operating temperature monitoring data, it was also possible to prove the occurrence of the overtemperature to which the inverter with lower SFI is subjected, reaching operating temperatures on the order of 80 °C. SFCR A had higher solar radiation of 4.2% over the year compared to SFCR B; however, SFCR B had a higher final yield of 11.86%. In this way, PV systems with undersized inverters will be losing electricity generation, in addition to reducing their useful life due to component stress, resulting in inverter changes over the life of the PV system.

Application and Analysis of Bipolar Membrane Electrodialysis for LiOH Production at High Electrolyte Concentrations: Current Scope and Challenges.

The objective of this work was to evaluate obtaining LiOH directly from brines with high LiCl concentrations using bipolar membrane electrodialysis by the analysis of Li+ ion transport phenomena. For this purpose, Neosepta BP and Fumasep FBM bipolar membranes were characterized by linear sweep voltammetry, and the Li+ transport number in cation-exchange membranes was determined. In addition, a laboratory-scale reactor was designed, constructed, and tested to develop experimental LiOH production tests. The selected LiCl concentration range, based on productive process concentrations for Salar de Atacama (Chile), was between 14 and 34 wt%. Concentration and current density effects on LiOH production, current efficiency, and specific electricity consumption were evaluated. The highest current efficiency obtained was 0.77 at initial concentrations of LiOH 0.5 wt% and LiCl 14 wt%. On the other hand, a concentrated LiOH solution (between 3.34 wt% and 4.35 wt%, with a solution purity between 96.0% and 95.4%, respectively) was obtained. The results of this work show the feasibility of LiOH production from concentrated brines by means of bipolar membrane electrodialysis, bringing the implementation of this technology closer to LiOH production on a larger scale. Moreover, being an electrochemical process, this could be driven by Solar PV, taking advantage of the high solar radiation conditions in the Atacama Desert in Chile.

Increase in secondary organic aerosol in an urban environment

Abstract. The evolution of fine aerosol (PM1) species as well as the contribution of potential sources to the total organic aerosol (OA) at an urban background site in Barcelona, in the western Mediterranean basin (WMB) was investigated. For this purpose, a quadrupole aerosol chemical speciation monitor (Q-ACSM) was deployed to acquire real-time measurements for two 1-year periods: May 2014–May 2015 (period A) and September 2017–October 2018 (period B). Total PM1 concentrations showed a slight decrease (from 10.1 to 9.6 µg m−3 from A to B), although the relative contribution of inorganic and organic compounds varied significantly. Regarding inorganic compounds, SO42-, black carbon (BC) and NH4+ showed a significant decrease from period A to B (−21 %, −18 % and −9 %, respectively), whilst NO3- concentrations were higher in B (+8 %). Source apportionment revealed OA contained 46 % and 70 % secondary OA (SOA) in periods A and B, respectively. Two secondary oxygenated OA sources (OOA) were differentiated by their oxidation status (i.e. ageing): less oxidized (LO-OOA) and more oxidized (MO-OOA). Disregarding winter periods, when LO-OOA production was not favoured, LO-OOA transformation into MO-OOA was found to be more effective in period B. The lowest LO-OOA-to-MO-OOA ratio, excluding winter, was in September–October 2018 (0.65), implying an accumulation of aged OA after the high temperature and solar radiation conditions in the summer season. In addition to temperature, SOA (sum of OOA factors) was enhanced by exposure to NOx-polluted ambient and other pollutants, especially to O3 and during afternoon hours. The anthropogenic primary OA sources identified, cooking-related OA (COA), hydrocarbon-like OA (HOA), and biomass burning OA (BBOA), decreased from period A to B in both absolute concentrations and relative contribution (as a whole, 44 % and 30 %, respectively). However, their concentrations and proportion to OA grew rapidly during highly polluted episodes. The influence of certain atmospheric episodes on OA sources was also assessed. Both SOA factors were boosted with long- and medium-range circulations, especially those coming from inland Europe and the Mediterranean (triggering mainly MO-OOA) and summer breeze-driven regional circulation (mainly LO-OOA). In contrast, POA was enhanced either during air-renewal episodes or stagnation anticyclonic events.

Plant functional traits explain species abundance patterns and strategies shifts among saplings and adult trees in Araucaria forests

AbstractSpecies‐rich communities are composed of several locally rare and a few abundant species. A trait‐based approach can derive general explanations for such species abundance distribution. However, for tree species in forests, the intraspecific variation of traits associated with the ontogeny and understory/canopy conditions must be considered. Here, we quantified intraspecific variation of leaf traits across saplings and adults in trees and tested if leaf and/or regenerative traits mediate the species abundance distribution of saplings and adults, and if saplings abundance also determines the abundance of adults in tree communities of Araucaria forests in Southern Brazil. We found intraspecific variation for specific leaf area (SLA) and leaf dry matter content (LDMC), but not for leaf area (LA). Adults have higher LDMC and lower SLA than saplings, suggesting a shift in investment strategies. Species abundant in saplings were associated with larger LA, whereas abundant species in the adults had lower SLA and LA and a larger number of seeds per fruit. The abundance of saplings also contributed to explaining the abundance of species as adults. Saplings experience low light availability in the understory, larger leaves are essential to maximising light capture. On the other hand, adult trees face high irradiation, windy and frost exposure conditions; species with lower SLA reach higher abundance. Regenerative traits were only relevant for the model of adults. Species abundance distribution in forests is related to functional traits, but the relationship is distinct for saplings and adults as leaf traits vary according to the ontogenetic stage and/or the environmental conditions imposed to individuals. In addition, we suggest the assembly of trees in the upper forest stratum is not only mediated by abiotic and biotic filters that favour some leaf and regenerative attributes, but also by lasting effects of variables that filtered out individuals in former development stages.