Results 1 - 10 of 5681
Results 1 - 10 of 5681. Search took: 0.032 seconds
|Sort by: date | relevance|
[en] Gridded hourly temperature forecasts from the Bureau of Meteorology's Gridded Operational Consensus Forecasting (GOCF) system are combined in real time with the Australian Water Availability Project (AWAP) gridded daily temperature analyses to produce gridded daily maximum and minimum temperature forecasts with lead times from one to five days. These forecasts are compared against the historical record of AWAP daily temperature analyses (1911 to present), to identify regions where record or near-record temperatures are predicted to occur. This paper describes the GOCF/AWAP system, showing how the daily maximum and minimum temperature forecasts are prepared from the hourly forecasts, and how they are bias-corrected in real time using the AWAP analyses, against which they are subsequently verified. Using monthly climatologies of long-term daily mean, standard deviation and all-time highest and lowest on record, derived forecast products (for both maximum and minimum temperature) include ordinary and standardised anomalies, 'forecast - highest on record' and 'forecast - lowest on record'. Compensation for the climatological variation across the country is achieved in these last two products, which provide the necessary guidance as to whether or not record-breaking temperatures are expected, by expressing the forecast departure from the previous record in both 0C and standard deviations.
[en] The prediction of global sea-level rise is one of the major challenges of climate science. While process-based models are still being improved to capture the complexity of the processes involved, semi-empirical models, exploiting the observed connection between global-mean sea level and global temperature and calibrated with data, have been developed as a complementary approach. Here we investigate whether twentieth century sea-level rise could have been predicted with such models given a knowledge of twentieth century global temperature increase. We find that either proxy or early tide gauge data do not hold enough information to constrain the model parameters well. However, in combination, the use of proxy and tide gauge sea-level data up to 1900 AD allows a good prediction of twentieth century sea-level rise, despite this rise being well outside the rates experienced in previous centuries during the calibration period of the model. The 90% confidence range for the linear twentieth century rise predicted by the semi-empirical model is 13–30 cm, whereas the observed interval (using two tide gauge data sets) is 14–26 cm. (letter)
[en] Consumers are increasingly demanding the interior of cars to be comfortable even in the case of more economic commercial segments. Thus, the development of materials with thermoregulation properties has assumed renewed interest for these particular applications. An attempt has been made to prepare a multilayer PVC-based synthetic leather with paraffinic PCMs to be applied on a car seat. The thermal behaviour of the material was analysed using Alambeta apparatus, a thermo-camera and a thermal manikin. The results obtained show that the synthetic leather with incorporated PCMs gives cooler feeling and has higher reaction times regarding environmental temperature variations than the material without PCMs incorporation. Globally, the new designed material allowed greater thermal comfort to the cars´ inhabitants. In addition, the material quality was evaluated according to the standard of the customer, BMW 9,210,275; Edition / Version 4, 2010-10-01 revealing that the material meets all the requirements under test, except for the performance in terms of flexibility. (paper)
[en] Highlights: • VIRTIS(M)-VEX measurements are used to retrieve mesospheric temperature profiles. • Results for two independent retrieval methods (Chahine, Bayes) are compared. • Temperature profiles are in good agreement for both algorithms. • Corresponding standard deviations do not exceed 5 K for altitudes above 59 km. • Cold collar and hot polar regions are observed. We present vertical temperature profiles derived by two different retrieval methods from nighttime radiation measurements performed by VIRTIS(M)-VEx (Visible and Infrared Thermal Imaging Spectrometer, M channel—Venus Express). The Bayesian approach to the optimal estimation method and the relaxation method are applied in this study. This is a first attempt to present and compare results obtained from two independent methods. It allows us to be more convinced of our interpretation. After comparison of temperature profiles we conclude that both retrieval methods are able to sound the atmospheric layers higher than 59 km (In our conclusion we have no preference for any approach. Two methodologies are of equivalent value. Both methods resolve temperature inversions at high altitudes (∼84 km), the quality of fits for all observations is equally well. Only for the Bayesian approach, the retrieval uncertainty above 62 km up to 95 km is less than 2 K. A disadvantage of this method is the time-consuming calculation of weighting functions. The atmospheric temperatures over the “cold collar” region located at 60°S–75°S (60–70 km) are ∼10 K smaller than for latitudes poleward of 75°S (polar region). The cold collar region is seen very clearly in our results for both methods.
[en] The paper presents the results of characterization of the high-power quantum cascade lasers for 8 μm spectral range. Lasers demonstrate stable generation at room temperature with the maximum output peak power of ∼ 0.9 W per facet. (paper)
[en] We have studied the FMO, LHCII and PSII reaction center complex by electronic 2D spectroscopy. At ambient temperature the electronic coherences are too short lived to play any functional role in the natural energy transfer.
[en] Luminescent polymeric nanoparticles (LPNs) with aggregation-induced emission (AIE) feature have emerged as the most promising candidates for biological imaging owing to their unique AIE feature, great water dispersity, strong fluorescence, low cytotoxicity and biocompatibility. Although numerous successful strategies for construction of AIE-active LPNs have been developed, the preparation of dynamic linkages containing AIE-active LPNs based on multicomponent reactions has been rarely reported. In this work, we report a facile method for the formation of AIE-active LPNs via a one-pot conjugation of PEG-B(OH)2, 1-thioglycerol and AIE-active dye PhE-alc in short time under rather mild reaction conditions (e.g. ambient temperature, air atmosphere, absent of metal catalysts and in the present of water). The successful formation of AIE-active mPEG-PhE LPNs was confirmed by different characterization techniques in details. The great optical and biological properties certified their applicable for biological imaging application. More importantly, the novel method for the formation of AIE-active LPNs is rather simple, high efficiency and atom economy, which greatly enriched their practical biomedical applications. - Graphical abstract: A facile one-pot strategy based on the formation of dynamic bonds has been developed for the fabrication of luminescent polymeric nanoparticles with aggregation-induced emission feature. - Highlights: • Aggregation-induced emission luminescent polymeric nanoparticles • A one-pot multicomponent reaction • AIE-active LPNs containing dynamic linkages • The AIE-active LPNs are promising for biomedical applications.
[en] Single crystal X-ray and synchrotron X-ray powder diffraction have been used to probe the structure of Ba3NaIr2O9 from 300 K down to 20 K. Ba3NaIr2O9 is found to undergo a structural transition from hexagonal symmetry, P63/mmc, at ambient temperature to monoclinic symmetry, C2/c, at low temperature. The evolution of the unit cell volume upon cooling is indicative of a higher order structural transition, and the symmetry breaking becomes apparent as the temperature is decreased. The low temperature monoclinic structure of Ba3NaIr2O9 contains strongly distorted (NaO6) and (IrO6) octahedra in comparison to the room temperature hexagonal structure.
[en] The possibility of limiting the increase of the average earth atmospheric temperature to 2 Celsius degrees appears to belong to the past. Rich countries have succeeded in blocking or even reducing their emissions of greenhouse effect gases but they still rely heavily on fossil energies. As for developing countries their development is essentially based on fossil energies they use in a growing tendency. It is difficult to image how these trends could be reversed in a short time. In the article the carbon budget is defined as the cumulated quantity of carbon that will avoid exceeding a fixed value of temperature. For instance a 2 degrees increase of temperature correspond to a CO_2 concentration in the atmosphere of 450 ppm. In the case where nothing was done and that fossil energies were used until their exhaustion, the carbon budget would reach 657 ppm and the corresponding increase of temperature would be beyond 4 degrees. (A.C.)