Optimized stencil print for low Ag paste consumption and high conversion efficiencies

We evaluate industrial-type PERC solar cells applying a dual printed front grid with stencil printed Ag fingers. We vary the Ag paste consumption for the finger print between 8.4 mg and 120.4 mg per 156 x 156 mm(2) wafer (weighted after printing before drying) by using polyurethane squeegees with different shore hardness as well as a metal squeegee and by varying the printing pressure to obtain different finger heights. The busbar consumes additional 19.5 mg Ag paste. We obtain average finger heights from 5.9 mu m up to 24.3 mu m for 55 mu m to 65 mu m wide fingers. The resulting PERC solar cells show an average efficiency of 20.2% for finger paste consumptions above 60 mg. In contrast, a strong reduction of the conversion efficiency with less than 60 mg finger paste consumption is observed since the increased series resistance reduces the FF. By analytical modelling, we compare the calculated series resistance to the experimental data and observe a good accordance for more than 40 mg finger paste consumption whereas the experimental series resistance slightly exceed the modelled values below 40 mg. In addition, we use numerical simulations to investigate the series resistance dependence on the finger height which shows higher experimental values for finger height below 10 mu m. The deviation of the measured series resistance and the two modelled cases is mostly due to inhomogeneous distribution of finger height profiles and finger interruptions on the solar cells with front finger paste consumption of less than 40 mg. For finger paste consumption below 60 mg, we find that also the specific contact resistance increases. A physical model of the root cause for this dependence still has to be found

Advancements in decadal climate predictability: the role of nonoceanic drivers

We review recent progress in understanding the role of sea ice, land surface, stratosphere, and aerosols in decadal-scale predictability and discuss the perspectives for improving the predictive capabilities of current Earth system models (ESMs). These constituents have received relatively little attention because their contribution to the slow climatic manifold is controversial in comparison to that of the large heat capacity of the oceans. Furthermore, their initialization as well as their representation in state-of-the-art climate models remains a challenge. Numerous extraoceanic processes that could be active over the decadal range are proposed. Potential predictability associated with the aforementioned, poorly represented, and scarcely observed constituents of the climate system has been primarily inspected through numerical simulations performed under idealized experimental settings. The impact, however, on practical decadal predictions, conducted with realistically initialized full-fledged climate models, is still largely unexploited. Enhancing initial-value predictability through an improved model initialization appears to be a viable option for land surface, sea ice, and, marginally, the stratosphere. Similarly, capturing future aerosol emission storylines might lead to an improved representation of both global and regional short-term climatic changes. In addition to these factors, a key role on the overall predictive ability of ESMs is expected to be played by an accurate representation of processes associated with specific components of the climate system. These act as “signal carriers,” transferring across the climatic phase space the information associated with the initial state and boundary forcings, and dynamically bridging different (otherwise unconnected) subsystems. Through this mechanism, Earth system components trigger low-frequency variability modes, thus extending the predictability beyond the seasonal scale

Transient climate simulations from the Maunder Minimum to present day: Role of the stratosphere

Transient climate simulations are performed covering the period from 1630 to 2000. A vertically extended version of a coupled atmosphere-ocean general circulation model is used, including a detailed representation of the stratosphere. One simulation is driven by changes in total solar irradiance due to solar activity as well as volcanic eruptions and changes in greenhouse gas (GHG) concentrations. A second simulation additionally includes changes in short-wave heating due to prescribed photochemical changes in ozone. The simulations are compared with reconstructions and other simulations employing less resolved stratosphere. The inclusion of the higher resolved stratosphere plays only a moderate role for the simulated climate variability on the hemispheric scale. Larger implications are found for regional scales. Both simulations reveal a shift of the North Atlantic Oscillation toward a more positive phase from the Maunder Minimum to present day, mainly attributed to anthropogenic increase in concentration of well-mixed GHG. Increase in GHG is related to a more disturbed stratospheric polar vortex resulting in an only moderate strengthening of tropospheric westerlies over Europe compared with the tropospheric version of the model. On multidecadal to centennial time scales the stratospheric solar forcing substantially contributes to the climate change signal in the stratosphere, and there is clear evidence for an impact on the tropospheric circulation

Ice conditions for maritime traffic in the Baltic Sea in future climate

Ice conditions for maritime traffic in the Baltic Sea in past/present (1961–2005) and future climates (2006–2100) were investigated. To model the ice conditions, a state-of-the-art ocean model, Nemo-Nordic, with a coupled ice model, LIM3, was applied. The model is forced with downscaled atmospheric fields from two global climate models using two different greenhouse-gas concentration scenarios giving an ensemble of four realisations of possible future ice conditions. Even though ice extent will be reduced in future climate and ice seasons will become shorter, completely ice-free winters are unlikely during the present century. In future climate, the ice becomes thinner, thus fewer traffic restrictions will be needed, but with a large inter-annual variability. In future climate, the ice will also become more mobile

On the kinetics of high temperature oxidation of copper foils: governmentretains for itself, and others act- Ig on ils behalf, a paid-up, nonexclusive

A quantitative M SitU QEX4FS investigation revocable worldwide license in said article I ;eproduce, prepare derivative works, dLsnbute copies 10the public, and perform pubcly and display publicly, by or on behalf of Ie Government. N. Hilbrandt, S. WassermanH, Th. Buhrmester were resolved using high quality, high temperature CU20 and CUOstandards for CU-KXAFS and CU-KPCA [2] analysis. These were prepared from copper foils using the same experimental techniques as for the oxidation under study. As the reaction can be devided into a step-wise oxidation mechanism: we attempted to check 2 G + 0.502+ CU20 'CU20+0.502 + 2 Cuo whether the formation of CUO is kinetically inhibited (delayed) or whether it takes place simultaneously to the formation of CUZO.To achieve an optimal time resolution the QEXAI?S technique [3] was applied. This investigation was completed by XRD and SEM investigations on samples quenched within the oxidation period. eriments: The investigations were pediormed on commercially available copper foils (GOODFELLOW, thickness 7.8 M light testet ultra pure> 99.99'%o) in a high temperature iimace (770 K< T <1090 K) under continuous gas flow on beamlineROEMOII at HASYLAB. The QEXAFS experiments were carried out in transition geometry on specimens (size7x7 rnmf ixed in a specially constructed Pt-AlzOs-sample.During the heating and equilibration period the conditionswere establishedso that copper remains in the singlephase field [4]. The compositionof the gas mixtures thereby determines the oxygen activity. Ehher CO/CG or Ar/H2 gas mixtures were used. The metal oxidation was induced by fast increase of the oxygen activity to. 0.21 (air) using a mass flow controller system. To guarantee reproducibtity the reduction of CUOto metal after an oxidationrun was also ana.lysedfollowedby severaloxidation-reductionruns. Results and discussion: Between T=770 and 1090 K oxidation induced changes in the CU-Kabsorption coefficientcan be clearlyresolved Studies of the Thermodynamics of Extraction f-Elements Kenneth L. Nash Chemistry Division Argonne National Laboratory 9700 S. Cass Ave. Argonne, IL 60439-4831, U.S.A Abstract Though they were discovered in the 18th century, practical applications of individual lanthanides were not possible until the development of first ion exchange and later solvent extraction techniques. Today, solvent extraction using lipophilic organophosphorus complexants is the principal separation technique applied for lanthanide production by hydrometallurgy. Separations chemistry (coprecipitation, ion exchange, and solvent extraction) also was central to both the discovery of the individual actinides and to the preparation of samples of sufficient purity to allow elucidation of their chemical/physical properties. Solvent extraction, in the form of the PUREX process, has become the single most important separations process in actinide technology. In this report, the basic thermodynamics of extraction of actinide and lanthanide metal ions is discussed

Ewolucja klimatu od późnego Minimum Maundera (1675–1715) do dzisiaj, ze szczególnym uwzględnieniem Polski

Pogoda i warunki klimatyczne zimą w Europie są związane ze zmiennością wielkoskalowej cyrkulacji atmosferycznej. W Polsce na wahania temperatury w zimie z roku na rok duży wpływ ma Oscylacja Północnoatlantycka. W artykule określono przebieg klimatyczny zimy w Polsce od Minimum Maundera (1700 r.) do końca XX wieku na podstawie symulacji klimatu chwilowym, sprzężonym modelem ogólnej cyrkulacji atmosferycznej. Model stanowi pionową, rozszerzoną wersję modelu ECHO-G i obejmuje stratosferę i mezosferę. Okazuje się, że długookresowa zmiana aktywności Słońca i antropogeniczne stężenie gazów cieplarnianych wpływa na Oscylację Północnoatlantycką (NAO), poprzez zmiany średniego ciśnienia na poziomie morza. Średnia temperatura w Polsce podczas późnego Minimum Maundera (1675-1715) była niższa o ponad 2 K niż współcześnie (1960-1990), na skutek czego średnia temperatura na półkuli północnej będzie jeszcze wyższa

Evaluation of the SMHI coupled atmosphere-ice-ocean model RCA4-NEMO

Den regionala kopplade atmosfär-is-havsmodellen RCA4-NEMO som utvecklats vid SMHI, utvärderas baserat på en ERA40-återanalys. Utvecklingen av den regionala klimatmodellen fortsätter men en första utvärdering presenteras här för att informera om aktuell status.RCA4-NEMO i aktuell status innehåller två modellkomponenter. Den regionala atmosfärsmodellen RCA4 täcker hela Europa och är tvåvägskopplad till en is-hav-modell för Nordsjön och Östersjön baserat på NEMO. Den används för tillfället för nedskalning av CMIP5-scenarier för detta århundrade för Nordsjön och Östersjön. Som en del av utvärderingen av RCA4-NEMO presenteras en analys och diskussion av hindcast-körning 1970-1999. Modellresulaten jämförs med observationsdata. Temperatur nära ytan och värmeflödet är förhållandevis bra vid en jämförelse med in-situ-mätningar och skattningar baserade på satellitdata. Salthalt och färskvattenutbyte är dock mindre bra. Momentumflödet från atmosfär till hav identifieras som en kritisk process i kopplingen mellan modellerna. Med undantag för färskvattensutbytet mellan atmosfär och hav är de klimatologiska egenskaperna nära ytan och motsvarande flöden jämförbara med klimatologiska observationer för perioden 1970-1999.AbstractThe regional, coupled atmosphere-ice-ocean model RCA4-NEMO developed at the SMHI is evaluated on the basis of an ERA40 hindcast. While the development of the regional climate model is continuing a first assessment is presented here to allow for an orientation about the status guo. RCA4-NEMO in its present form consists of two model components. The regional atmosphere model RCA4 covers the whole of Europe and is interactvely coupled to a North Sea and Baltic Sea ice-ocean model based on NEMO. RCA4-NEMO is currently being used to downscale CMIP5 scenarios for the North Sea and Baltic Sea region for this century. As a part of the validation of RCA4-NEMO we present an analysis and discussion of the hindcast period 1970-1999. The model realization is compared to observational records. Near surface temperatures and heat fluxes compare reasonably well with records of in-situ measurments and satellite derived estimates. For salinities and freshwater fluxes the agreement with observations in not satisfactory yet. The momentum fluxes transferred from the atmosphere to the ice-ocean model are identified as on of the sensitive processes in the coupling of both model components. Except for the freshwater exchange between atmosphere and ocean the climatological near surface properties and corresponding fluxes compare well with climatological estimates for the period 1970-1999