• Energy Research
• Other research products close
• AU close
• CL close

Abstract Body: Metal-halide perovskite solar cells (PSCs) are the most promising photovoltaic (PV) technology owing to their cost-effective processing, tunable energy band-gaps, long carrier diffusion lengths, unique defect tolerance, and ���self-healing��� capabilities. Despite considerable efforts, the physical mechanisms for the inferior stability of PSCs are not well understood. Some researchers propose that structural defects are the main source of deterioration because they serve as a channel for moisture/oxygen stressors. Others claim that grain boundaries are benign, and the degradation is attributed to trapped charges in the perovskite absorber itself. A robust measurement approach that can characterize individual microstructures (e.g., grain, grain boundary, interface) is required. Focused ion beam (FIB) milling is a well-established sample preparation method that can remove the surface roughness of polycrystalline thin-films. An atomically-smooth surface allows local optoelectronic measurements of a microstructured PV with minimum artifacts from its innate rough surface. While extremely useful, high-energy ion beams (< 30 keV) irradiated on a hybrid organic-inorganic PSC may induce structural damage and/or chemical degradation. In this work, we investigate possible beam damage on PSCs prepared by focused argon (Ar) ion-beam at various doses. In addition, we use Monte-Carlo simulations to estimate the thickness of the damage layer. Our PSC devices were fabricated in a multilayer configuration: Au (60 nm) / Spiro-OMeTAD (220 nm) / MAPbI3 (550 nm) / MoOx (5 nm) / ITO (200 nm). Here, MA is methylammonium, and Spiro-OMeTAD stands for 2,2',7,7'-Tetrakis [N, N-di(4-methoxyphenyl) amino]-9,9'- spirobifluorene. We performed a series of Ar ion milling processes at room temperature (Fischione Model 1060), with the incident beam irradiated at shallow angles of 1�� and 3��. The beam voltage was fixed at 4 kV, and the PSCs were milled for 5 min, 10 min, 15 min, and 20 min. At a first glance, we did not observe any notable changes with the samples milled at an incident beam angle of 1��. In contrast, the 3�� milled PSCs showed color changes with an increase of milling time. We are currently working on quantitative EDS (Energy Dispersive X-Ray Spectroscopy) analysis to obtain the evolution of I/Pb ratio at different ion beam doses. It has been reported in the literature that the decrease of the I/Pb from 3 to a lower value indicates compositional deterioration (i.e., MAPbI3 is partially converted to PbI2). To gain a deep understanding into the interaction of the Ar ion beam with PSCs, we performed Monte-Carlo Simulations. In our model, 20,000 Ar ions at 4 keV were irradiated into MAPbI3 layer at a shallow angle of 3�� and 30�� from the surface. The estimated damage layer was calculated based on the substrate displacement density. Using a constant contour representing 5 % of the peak damage density, we obtained the damage depth of 8 nm and 13 nm for the incident Ar+ beam angle of and, respectively. The integrated analysis based on the simulations and the EDS measurements are in progress. Our results provide qualitative information of possible beam damage of PSCs that can occur during sample preparation. We will discuss the mitigation strategies to minimize the beam damage while characterizing the microstructural properties of PSCs. This work was supported by the U.S. Department of Energy���s Office of Energy Efficiency and Renewable Energy (EERE) under the DE-FOA-0002064 program award number DE-EE0008985. The assistance of Utah Nanofab is also acknowledged.

The boron isotope systematics has been determined for azooxanthellate scleractinian corals from a wide range of both deep-sea and shallow-water environments. The aragonitic coral species, Caryophyllia smithii, Desmophyllum dianthus, Enallopsammia rostrata, Lophelia pertusa, and Madrepora oculata, are all found to have relatively high d11B compositions ranging from 23.2 per mil to 28.7 per mil. These values lie substantially above the pH-dependent inorganic seawater borate equilibrium curve, indicative of strong up-regulation of pH of the internal calcifying fluid (pH(cf)), being elevated by ~0.6-0.8 units (Delta pH) relative to ambient seawater. In contrast, the deep-sea calcitic coral Corallium sp. has a significantly lower d11B composition of 15.5 per mil, with a corresponding lower Delta pH value of ~0.3 units, reflecting the importance of mineralogical control on biological pH up-regulation. The solitary coral D. dianthus was sampled over a wide range of seawater pH(T) and shows an approximate linear correlation with Delta pH(Desmo) = 6.43 - 0.71 pH(T) (r**2 = 0.79). An improved correlation is however found with the closely related parameter of seawater aragonite saturation state, where Delta pH(Desmo) = 1.09 - 0.14 Omega(arag) (r**2 = 0.95), indicating the important control that carbonate saturation state has on calcification. The ability to up-regulate internal pH(cf), and consequently Omega(cf), of the calcifying fluid is therefore a process present in both azooxanthellate and zooxanthellate aragonitic corals, and is attributed to the action of Ca2+ -ATPase in modulating the proton gradient between seawater and the site of calcification. These findings also show that the boron isotopic compositions (d11Bcarb) of aragonitic corals are highly systematic and consistent with direct uptake of the borate species within the biologically controlled extracellular calcifying medium.

Climatic change will affect crop yields and management. By the year 2050, the mean temperature could increase by 1.5 °C; and by the year 2100 between 1.0 to 3.5 °C. There are few studies on this subject in Chile. At the international level, estimated climatic changes in temperate and tropical zones could negatively affect wheat (Triticum vulgare L.) and corn (Zea mays L.) production, as examples. The objective of this study was to determine the relationship between agricultural systems and climatic change by using the Ricardian Method. Specific objectives were to evaluate and quantify the relationship of climatic variables (precipitation and temperature) with economic variables under several realities of farms, to simulate the impact of scenarios of climatic change, to propose general orientations of adaptation and to evaluate the Ricardian Method with Chilean data. Economic and productive information from farmers belonging to Technological Transfer Groups (GTT) of the Agricultural Research Institute (INIA) was collected. The Ricardian Method explained 37.6% of land value variation. The highest values were in areas with moderate temperatures and precipitation. Temperature had a lower relationship to land value than precipitation. Under specific conditions (type of producer, irrigation, extension) were detected behaviors that require further analysis. Upon simulating change of temperature and precipitation, the negative impacts on land value tended to be of lower magnitude than in other warmer regions. A tendency was observed for increased temperature to be beneficial, and a neutral to positive effect with less precipitation. The outputs could initially guide specific strategies of adaptation and mitigation

The potential contribution of kelp forests to blue carbon sinks is currently of great interest but interspecific variance has received no attention. In the temperate Northeast Atlantic, kelp forest composition is changing due to climate-driven poleward range shifts of cold temperate Laminaria digitata and L. hyperborea and warm temperate L. ochroleuca. To understand how this might affect the carbon sequestration potential of this ecosystem, we quantified interspecific differences in carbon export and decomposition alongside changes in detrital photosynthesis and biochemistry. We found that while warm temperate kelp exports up to 71% more carbon per plant, it decomposes up to 155% faster than its boreal congeners. Elemental stoichiometry and polyphenolic content cannot fully explain faster carbon turnover, which may be attributable to contrasting tissue toughness or unknown biochemical and structural defences. Faster decomposition causes the detrital photosynthetic apparatus of L. ochroleuca to be overwhelmed 20 d after export and lose integrity after 36 d, while detritus of cold temperate species maintains carbon assimilation. Depending on the photoenvironment, detrital photosynthesis could further exacerbate interspecific differences in decomposition via a potential positive feedback loop. Through compositional change such as the predicted prevalence of L. ochroleuca, ocean warming may therefore reduce the carbon sequestration potential of such temperate marine forests. Data are deposited as CSV files and can be opened with any data software. The code accompanying these data is deposited at github.com/lukaseamus/CSP alongside further usage information. We place no restrictions on data usage.

We report pollen, charcoal and diatom records from the upper 4 m of a core from Inle Lake, Myanmar, spanning the entire Holocene, to investigate the changing palaeoenvironments in which early agriculture developed. From 12,000 to 10,500 cal yr BP a grass swamp existed until it was flooded by rising lake levels, indicated by the onset of marl deposition at the site. The onset of higher lake levels coincided with a transition from conifer-rich forest to mixed deciduous-evergreen forest, and a reduction in local biomass burning. Lake levels remained high until 6400 cal yr BP, thereafter fluctuating with possible dry phases at 4050, 2400 and 1100 cal yr BP. Increased burning is apparent from 2200 cal yr BP inferred to represent the onset of human forest clearance to its very reduced state today. The Inle Lake record compares with Holocene sequences in China, Thailand and India and marine cores south of Myanmar, which similarly show a regional pattern of drier conditions in the early Greenlandian stage, followed by maximum lake levels in the early Northgrippian stage. Fluctuating lake levels are evident in the later Northgrippian and Meghalayan stages after 6000 cal yr BP. This pattern coincides with precessional reduction in summer insolation in the region, which weakens the Asian Monsoon. The present-day bare catchments of Inle Lake probably mostly resulted from forest destruction over the last 2000 years although hints of human presence can be inferred throughout the older record.

Although alcohol is known to be a carcinogen for humans, ethanol-genotoxicity studies are incomplete. Ethanol seems not to be a bacterial mutagen, but the results are conflicting in rodent assays. We investigate the genotoxicity in the bone marrow micronucleus (MN) test and in the dominant lethal mutation (DLM) assay using two long-term ethanol exposure protocols. In the MN test, mice consumed three doses (5, 10 and 15% v/v) for 32 weeks. MN induction was compared to two control groups of 5- and 38-week-old mice (the ages of the treated mice when the treatment was initiated and when they were killed, respectively). For the three groups treated with ethanol there was no significant increase in MN induction as compared to the first control group, but observed MN frequencies were significantly lower than in the 38-week-old control group. This suggests a protective effect against genotoxic damage caused by aging, probably due to ethanol action as a hydroxyl radical scavenger. In the DLM assay, male mice drank ethanol at 15% or 30% (v/v) for 20 weeks. In both groups the number of dead implants was similar to the control, but there was a significant reduction in total implants, indicating a pre-implantation loss.

The ‘4 per mille Soils for Food Security and Climate’ was launched at the COP21 with an aspiration to increase global soil organic matter stocks by 4 per 1000 (or 0.4 %) per year as a compensation for the global emissions of greenhouse gases by anthropogenic sources. This paper surveyed the soil organic carbon (SOC) stock estimates and sequestration potentials from 20 regions in the world (New Zealand, Chile, South Africa, Australia, Tanzania, Indonesia, Kenya, Nigeria, India, China Taiwan, South Korea, China Mainland, United States of America, France, Canada, Belgium, England & Wales, Ireland, Scotland, and Russia). We asked whether the 4 per mille initiative is feasible for the region. The outcomes highlight region specific efforts and scopes for soil carbon sequestration. Reported soil C sequestration rates globally show that under best management practices, 4 per mille or even higher sequestration rates can be accomplished. High C sequestration rates (up to 10 per mille) can be achieved for soils with low initial SOC stock (topsoil less than 30 t C ha− 1), and at the first twenty years after implementation of best management practices. In addition, areas which have reached equilibrium will not be able to further increase their sequestration. We found that most studies on SOC sequestration only consider topsoil (up to 0.3 m depth), as it is considered to be most affected by management techniques. The 4 per mille number was based on a blanket calculation of the whole global soil profile C stock, however the potential to increase SOC is mostly on managed agricultural lands. If we consider 4 per mille in the top 1m of global agricultural soils, SOC sequestration is between 2-3 Gt C year− 1, which effectively offset 20–35% of global anthropogenic greenhouse gas emissions. As a strategy for climate change mitigation, soil carbon sequestration buys time over the next ten to twenty years while other effective sequestration and low carbon technologies become viable. The challenge for cropping farmers is to find disruptive technologies that will further improve soil condition and deliver increased soil carbon. Progress in 4 per mille requires collaboration and communication between scientists, farmers, policy makers, and marketeers.

The progression of climate warming will expose ectotherms to transient heatwave events and temperatures above their tolerance range at increased frequencies. It is therefore pivotal that we understand species’ physiological limits and the capacity for various controls to plastically alter these thresholds. Exercise training could have beneficial impacts on organismal heat tolerance through improvements in cardio-respiratory capacity, but this remains unexplored. Using juvenile Chinook salmon (Oncorhynchus tshawytscha), we tested the hypothesis that exercise training improves heat tolerance through enhancements in oxygen-carrying capacity. Fish were trained once daily at 60% of their maximum sustainable swim speed for 60 min. Tolerance to acute warming was assessed following three weeks of exercise training, measured as the critical thermal maximum (CTMax). CTMax measurements were coupled with examinations of the oxygen carrying capacity (haematocrit, haemoglobin concentration, relative ventricle size, and relative splenic mass) as critical components of the oxygen transport cascade in fish. Contrary to our hypothesis, we found that exercise training did not raise the CTMax of juvenile Chinook salmon with a mean CTMax increase of just 0.35°C compared to unexercised control fish. Training also failed to improve the oxygen carrying capacity of fish. Exercise training remains a novel strategy against acute warming that requires substantial fine-tuning before it can be applied to the management of commercial and wild fishes.

Reef managers cannot fight global warming through mitigation at local scale, but they can use information on thermal patterns to plan for reserve networks that maximize the probability of persistence of their reef system. Here we assess previous methods for the design of reserves for climate change and present a new approach to prioritize areas for conservation that leverages the most desirable properties of previous approaches. The new method moves the science of reserve design for climate change a step forwards by: (1) recognizing the role of seasonal acclimation in increasing the limits of environmental tolerance of corals and ameliorating the bleaching response; (2) including information from several bleaching events, which frequency is likely to increase in the future; (3) assessing relevant variability at country scales, where most management plans are carried out. We demonstrate the method in Honduras, where a reassessment of the marine spatial plan is in progress.

Rising temperatures pose a significant threat to the survival of ectothermic animals. Thermal physiological traits, including upper thermal limits, are proven useful traits to assess the vulnerability of ectotherms to changing temperatures. For instance, one may use upper thermal limits to estimate current and future thermal safety margins (i.e., the proximity of upper thermal limits to experienced temperatures), use this trait in coercion with other physiological traits in species distribution models, or investigate the plasticity, heritability and evolvability of these traits for buffering the impacts of changing temperatures. While datasets on thermal tolerance limits have been previously compiled, they often report single estimates for a given species, do not present measures of data dispersion, and are biased towards certain parts of the globe. In this project, we systematically searched the literature in seven languages and produced a dataset of over 3000 heat tolerance estimates for 616 amphibian species. I will first present how the dataset we compiled can be used to address various questions in ecophysiology, and its limitations. Indeed, despite its scope, this dataset also suffered from geographical biases and captured less than 10% of described amphibian species. Here, I will demonstrate how we can fill the missing parts of this puzzle using powerful imputation procedures and estimate the heat tolerance of most described amphibian species. I will then demonstrate how we used this comprehensive database to estimate the vulnerability of the worlds’ amphibians to current and projected temperatures.