Chronic Stress Induces Sex-Specific Alterations in Methylation and Expression of Corticotropin-Releasing Factor Gene in the Rat

Contains fulltext : 91627.pdf (publisher's version ) (Open Access

Tien jaar ervaring met de Europese Kaderrichtlijn Water: Ambities en Ambivalenties

Item does not contain fulltex

Tien Jaar Ervaring met de Europese Kaderrichtlijn Water: ambities en ambivalenties

De Kaderrichtlijn Water (KRW) is een van de belangrijkste en meest omvattende milieurichtlijnen in het hedendaagse waterbeheer. De richtlijn vraagt onder meer om een (internationale) stroomgebiedbenadering, actieve betrokkenheid van belanghebbenden, het terugwinnen van kosten voor waterdiensten en stelt ecologische en chemische kwaliteitsdoelen voor alle Europese oppervlakte- en grondwateren centraal. Ze is in deze aspecten vernieuwend. Er is lang en op hoog politiek niveau over deze richtlijn onderhandeld en dit heeft geresulteerd in een complex aan spelregels die tevens multi-interpretabel zijn. Dit betreft zowel de organisatorische als de inhoudelijke kant van de KRW. De beoogde ambities en innovaties van de KRW worden dan ook gekenmerkt door ambivalentie. Daarnaast laat de Europese Unie veel over aan de lidstaten, waardoor vele keuzes pas tijdens het implementatieproces gemaakt worden. De KRW is een invloedrijke en soms ingrijpende richtlijn. Tegelijkertijd is het niet verbazingwekkend dat bestuurders en waterbeheerders in Nederland en Vlaanderen worstelen met de vertaling van de voorschriften naar de dagelijkse praktijk. In deze bundel presenteren waterbeheerders en onderzoekers uit Nederland en Vlaanderen essays over verschillende elementen uit het KRW proces. De essays zijn tot stand gekomen in discussies tussen onderzoekers, beleidsmakers en –adviseurs van verschillende organisaties, die gezamenlijk hebben teruggekeken op 10 jaar KRW. In hun bijdragen belichten zij de ambities en ambivalenties telkens vanuit hun eigen praktijk. De observaties, lessen en aanbevelingen voor de toekomst in deze bundel zijn bedoeld voor al diegenen die bij de uitvoering van de richtlijn betrokken zijn, er direct of indirect belang bij hebben, er onderzoek naar doen of geïnteresseerd zijn in het hedendaagse waterbeheer

Slow Shallow Energy States as the Origin of Hysteresis in Perovskite Solar Cells

Organic-inorganic metal halide perovskites have attracted a considerable interest in the photovoltaic scientific community demonstrating a rapid and unprecedented increase in conversion efficiency in the last decade. Besides the stunning progress in performance, the understanding of the physical mechanisms and limitations that govern perovskite solar cells are far to be completely unravelled. In this work, we study the origin of their hysteretic behaviour from the standpoint of fundamental semiconductor physics by means of technology computer aided design electrical simulations. Our findings identify that the density of shallow interface defects at the interfaces between perovskite and transport layers plays a key role in hysteresis phenomena. Then, by comparing the defect distributions in both spatial and energetic domains for different bias conditions and using fundamental semiconductor equations, we can identify the driving force of hysteresis in terms of slow recombination processes and charge distributions.Photovoltaic Materials and Device

Opto-electrical modelling and roadmap for 2T monolithic Perovskite/CIGS tandem solar cells

Two terminal (2T) perovskite/copper-indium-gallium-selenide (CIGS) tandem solar cells combine high conversion efficiency with lightweight flexible substrates which can decrease manufacturing and installation costs. In order to improve the power conversion efficiency of these tandem solar cells, the use of advanced simulation tools is crucial to estimate the loss mechanisms. In this regard, most of the available simulation works on tandem solar cells are oriented to minimize optical losses and assuming simplifications for the electrical simulations in particular in the top and bottom cell interconnection at the so-called tunnel recombination junction (TRJ) neglecting the inner physics of the complete tandem device. Therefore, the effect of charge exchange mechanism between top and bottom soler cells on the external parameters of a tandem devices is not fully understood yet. In this work, we present an experimentally validated opto-electrical model based on the fundamental semiconductor equations for the study of loss mechanisms of a reference perovskite/CIGS solar cell. Different from other numerical works, because our simulation platform includes the fundamental working mechanisms of the layers comprising the TRJ, we can properly calculate the losses related to it. We firstly present the calibration and validation of our opto-electrical model with respect to three fabricated reference solar cells: top cell only, bottom cell only and tandem device. Then, we use the calibrated model to evaluate main loss mechanisms affecting the baseline tandem device. Finally, we use the model to propose a roadmap for the optimization of monolithic perovskite/CIGS tandem solar cells.Photovoltaic Materials and DevicesEthics & Philosophy of Technolog

Optical characterization of poly-SiO_x and poly-SiC_x carrier-selective passivating contacts

The optical modelling for optimizing high-efficiency c-Si solar cells endowed with poly-SiOx or poly-SiCx carrier-selective passivating contacts (CSPCs) demands a thorough understanding of their optical properties, especially their absorption coefficient. Due to the mixed phase nature of these CSPCs, spectroscopic ellipsometry is unable to accurately detect the weak free carrier absorption (FCA) at long wavelengths. In this work, the absorption coefficient of doped poly-SiOx and poly-SiCx layers as function of oxygen and carbon content, respectively, was obtained for wavelengths (300–2000 nm) by means of two alternative techniques. The first approach, photothermal deflection spectroscopy (PDS), was used for layers grown on quartz substrates and is appealing from the point of view of sample fabrication. The second, a novel inverse modelling (IM) approach based on reflectance and transmittance measurements, was instead used for layers grown on textured c-Si wafer substrates to mimic symmetrical samples. Although the absorption coefficients obtained from these two techniques slightly differ due to the different used substrates, we could successfully measure weak FCA in our CSPCs layers. Using an in-house developed multi-optical regime simulator and comparing modelled reflectance and transmittance with measured counterparts from symmetrical samples, we confirmed that with increasing doping concentration FCA increases; and found that the absorption coefficients obtained from IM can now be used to perform optical simulations of these CSPCs in solar cells.Photovoltaic Materials and DevicesElectrical Sustainable Energ