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Today, investigations on degradation and failure mechanisms in solar cells are often based on accelerated ageing tests (AAT), where failure effects are reproduced and quantified within a much shorter time period than the actual lifetime. This paper presents a study upon a novel approach of AAT for high concentration photovoltaic (HCPV) cells. The intended approach aims to overcome several limitations encountered in most of the AAT adopted up today, proposing the use of an alternative experimental set-up for performing nearly 400 times faster and more realistic thermal cycles, under real sun conditions (irradiation cycling), without the involvement of any environmental chamber. The cumulative impact of such very rapid irradiation/thermal cycles on the ageing of HCPV assemblies can be determined, both quantitatively and qualitatively, by evaluating specific pre-ageing and post-ageing diagnostic measurements by means of I – V characterization and scanning acoustic microscopy (SAM). The proposed irradiation/thermal cycling arrangement was successfully employed for performing accelerated ageing of both HCPV assemblies (cell receiver and heat sink) and bare HCPV cell receivers. Ultimate goal of this AAT approach is to provide the basis for a future work on the reliability analysis of the main degradation mechanisms and failure propagation in HCPV cell assemblies. [ABSTRACT FROM AUTHOR]

Abstract: The ice-loaded Labrador Current (LC) is an important component of the western North Atlantic circulation that influences the position and strength of the northern limb of the North Atlantic Current (NAC). This flow of cold and fresh Polar Waters originating from the Arctic has a marked impact on the North Atlantic climate, yet little is known about its variability beyond the instrumental period. In this study, we present the first sub-decadal alkenone-based 2000-year long sea-surface temperature (SST) records from the western Labrador Sea, a climatically crucial region at the boundary between the LC and the NAC. Our results show a clear link between the LC strength and the Northern Annular Mode (NAM), with a stronger NAM and a more vigorous LC during the Medieval Climate Anomaly (MCA). This suggests enhanced LC activity upon future global warming with implications for the Atlantic meridional overturning circulation (AMOC). [Copyright &y& Elsevier]

Evaluates the long-chain alkenones, unsaturated methyl and ethyl ketones, collected in the northwestern Mediterranean Sea. Establishment of calibration slope; Observation of alkenones distribution; Effect of water temperature on distribution of alkenones.

Abstract: The Uk′ 37 record and coccolithophorid remains in sediments from the early Pliocene Sicilian Trubi Formation (Punta di Maiata) have been estimated to assess the possible influence of changes in the alkenone-producing coccolithophorids on the Uk′ 37–temperature relationship. The samples were dominated by small Reticulofenestra (R. minuta and R. minutula) and the C37 and C38 methyl and ethyl unsaturation ratios (Uk′ 37, Uk 38Me and Uk 38Et) were similar to those found in modern populations (E. huxleyi and G. oceanica). Those results suggest that the Early Pliocene small Reticulofenetrids had a similar temperature sensitivity of Uk′ 37 to that found in present day. These results support the application of the Uk′ 37 modern calibrations to reconstruct SST at least back in the Pliocene. [Copyright &y& Elsevier]

Abstract: Paleohydrological changes in the southern South China Sea (SCS) combined with clay mineralogy have been investigated along core MD01-2393 recovered off the Mekong River mouth in order to assess the impact of sea level and East Asian monsoon rainfall intensity on erosion and weathering during the last 25,000yr. SSTs and δ 18O values determined on Globigerinoides ruber were used to estimate past changes of local seawater oxygen isotope (δ 18Ow). The close position of the studied core to the Mekong River mouth at sea level lowstand likely played a role in the δ 18Ow fluctuations resulting from changes of the monsoon rainfall and runoff into the Mekong River basin. The smectite/(illite+chlorite) and kaolinite/(illite+chlorite) ratios combined with the illite chemistry index during the Holocene show higher chemical weathering of detrital material originating mainly from the lower reach of the Mekong River. At shorter time scales, periods of strong monsoon rainfall are associated with an intensification of erosion of the Mekong River lowland favoured by the development of incised-valley systems inducing higher inputs of detrital material from the lower relative to the upper reach of the Mekong River. Our findings imply a rapid response of erosion processes of the Mekong River basin to the monsoon rainfall intensity changes. [Copyright &y& Elsevier]

Past and present environmental conditions over the Holocene along the Algerian coast involve complex atmosphere-hydrosphere-biosphere interactions and anthropogenic activities on adjacent watersheds. Atlantic Ocean surface waters entering the western Mediterranean Sea at the Gibraltar Strait create the Algerian Current, which flows along the North African coast in a succession of strong and large-scale eddies. Deep-water upwelling plumes are other recurrent hydrological features of the Algerian margin affecting regional environmental features. However, vegetation and paleohydrological changes that have occurred over the Holocene have not yet been described. To bridge this gap, a suite of paleoclimate proxies was analysed in marine core MD04–2801 (2067 m water depth) at a secular-scale resolution over the last 14 kyrs BP. Terrestrial (pollen grains) and marine (dinoflagellate cysts or dinocysts) palynological assemblages, as well as sedimentological (grain-size analysis and XRD-based quantitative analysis of clay minerals) and biomarkers (alkenones and n-alkanes), were determined to explore the links between past sea surface hydrological conditions and regional environmental changes on nearby watersheds. The over-representation of heterotrophic dinocyst taxa (Brigantedinium spp.) indicates strong planktonic productivity in the study area. Results shows that the links between dryness on land and surface hydrological conditions are expressed by: (i) recurrent upwelling cells during the relatively dry climate conditions of the Younger Dryas (12.7 to 11.7 ka BP), the Early Holocene (11.7 to 8.2 ka BP) and from 6 ka BP onwards, (ii) enhanced fluvial discharges between 8.2 and 6 ka BP during the African Humid Period concomitant with the colonization of coastal lands by Mediterranean forest. Middle to Late Holocene transition around 4.2 ka BP characterizes by the intense event reffered to here as the Algerian Mega Drought (4.3 to 3.9 ka BP). • Land-sea multiproxy approach on the Algerian Margin over the last 14 kyrs. • Productivity regimes closely associated with the vigour of the Algerian Current. • Settlement of modern production conditions since 3 ka BP. • First record of the Algerian Mega Drought event between 4.3 and 3.9 ka BP. • NPP fingerprint in marine sediments related to erosion and river runoff. [ABSTRACT FROM AUTHOR]

Abstract: The Nd isotopic composition of the aragonite skeleton of fossil deep-sea corals (Lophelia pertusa, Madrepora oculata and Desmophyllum dianthus) located in the northeastern Atlantic at water depths between 635 and 1300m was investigated to reconstruct changes in the Atlantic mid-depth gyre circulation during the past millennium. The coral εNd values varied systematically from −11.8 to −14.4 during the past 1500years, reflecting variations in seawater εNd and thus water mass provenance. Low εNd values (εNd=−14) occurred during the warm Medieval Climatic Anomaly (MCA) (between 1000AD and 1250AD) and during the most recent period (1950AD to 2000AD), interrupted by a period of significantly higher εNd values (~−12.5) during the Little Ice Age (LIA) (between 1350AD and 1850AD). One long-lived branching coral even recorded an abrupt systematic rise from low to high εNd values around 1250AD over the course of its 10-year growth period. These variations are interpreted to result from variable contributions of the subpolar and subtropical Atlantic intermediate water masses, which today are characterized by εNd values of −15 and ~−11, respectively. The low εNd values observed during the warm MCA and during recent times imply a strong eastward extension of the mid-depth subpolar gyre (SPG) induced by a dominant positive phase of the North Atlantic oscillation (NAO). During the LIA, water from the subtropical gyre (STG) and potentially from the Mediterranean Sea Water (MSW) propagated further northward, as indicated by the higher coral εNd values. This pattern suggests a negative mean state of the NAO during the LIA, with weaker and more southerly located Westerlies and a westward contraction of the SPG. Variations in the contributions of the two gyres imply changes in the heat and salt budgets at intermediate depths during the past millennia that may have contributed to changes in the properties of North Atlantic inflow into the Nordic Seas and thus deep-water formation. [Copyright &y& Elsevier]

Radiocarbon dates and marine tephra suggest that the upper 10 m of core MD99-2274 off North Iceland extends from ∼0 to ∼65 ka BP. A multi-proxy sediment and biomarker study at a ∼0.5 ky resolution is used to derive a paleoclimate scenario for this area of the southwestern Nordic Seas, which during the Holocene had intermittent excursions of icebergs and a seasonal cover of drifting sea ice across the site. The sortable silt mean size (S̅S̅) suggests a bottom current (1000 m depth) flow speed maximum to minimum range of ∼8 cm/s during Marine Isotope Stages 2–3, but the data are unreliable for the Holocene. Slow-down in flow speeds may be associated with massive ice and water discharges linked to the Hudson Strait ice stream (H-events) and to melt of icebergs from Greenland in the Nordic seas where convection would have been suppressed. Five pulses of sediment with a distinct felsic component are associated with iceberg transport from E/NE Greenland. Sea ice, open water and sea surface temperature (SST) biomarker proxies (i.e. IP 25 , HBI III, brassicasterol and alkenones) all point towards near-perennial sea ice cover during MIS 3 and 2, rather than seasonal sea ice or open water conditions. Indeed, our biomarker and sediment data require that the seas north of Iceland experienced a nearly continuous cover of sea ice, together with icebergs calved from ice stream termini, which drifted southward. The cross-correlation of the quartz % records between MD99-2274 and the well-dated core PS2644 in Blosseville Basin indicates significant coherence in the records at a multi-millennial (∼8 ky) timescale. A transition to open ocean conditions is evident from the early Holocene onwards, albeit with the occurrence of some drift ice and icebergs. • Multi-proxy biogeochemical, grain-size, and mineral analysis. • MIS 2 and 3 record of sea ice cover and ice-rafting in the Iceland Sea. • HBI, sterol and alkenone biomarkers point to extensive sea ice during MIS 3 and MIS 2. • Episodes of quartz input linked to a NE source (s). • Bottom currents at 1000 m depth combine THC Nordic outflow and saline density flow. [ABSTRACT FROM AUTHOR]