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In recent years, a rapid pace of climate change is becoming evident by a marked increase in the frequency and intensity of weather extremes, and this trend is expected to continue with an increase in global warming for decades to come. The paper presents the non-homogeneous Poisson process as a basis to model an environmental load process induced by non-stationary climate conditions. The distribution of maximum load generated by a non-stationary process is derived, which explicitly accounts for the loading frequency and intensity amplification over time. Using this distribution, structural reliability can be computed for any given time interval in future. The paper shows that traditional measures like the return period, extreme percentiles, and the annual probability of failure, would vary with time under the changing climate. Examples presented in the paper show that a modest amplification of the load magnitude has a drastic negative effect on reliability than that of the frequency of loading. Probabilistic models presented in this paper will be useful in revising currently used "stationary" design codes and ensuring a consistent level of safety in the non-stationary climate. • Non-homogeneous Poisson process for non-stationary reliability analysis. • Consideration of time-dependent frequency and intensity of applied loads. • An accurate, finite time solution for the non-stationary extreme load distribution. • The concept of the return period is not useful in the changing climate. • A modest load amplification has a major negative effect on reliability. [ABSTRACT FROM AUTHOR]

Abstract: This paper investigates the impact of internal curing on the service life of high-performance concrete (HPC) bridge decks by using analytical models to predict the times to onset of corrosion, onset of corrosion-induced damage, and failure of decks. Three bridge deck design options were compared: (i) normal concrete deck; (ii) HPC deck with supplementary cementing materials (SCM); and (iii) HPC deck with SCM and internal curing. It was found that the use of internal curing can extend the service life of high-performance concrete bridge decks by more than 20years, which is mainly due to a significant reduction in the rate of penetration of chlorides in concrete as a result of reduced early-age shrinkage cracking and reduced chloride diffusion. Compared to normal concrete, HPC with SCM and internal curing was predicted to add more than 40years to the service life of bridge decks in severe environmental conditions. Life-cycle cost reductions of 40% and 63% were estimated when conventional HPC and internally-cured HPC were used in bridge decks instead of normal concrete, respectively, despite the fact that the in-place unit cost of internally-cured HPC can be 4% higher than that of conventionally-cured HPC, which in turn can be up to 33% higher than that of normal concrete. This is due to a longer service life and less frequent maintenance activities offered by low-permeability HPC bridge decks. [Copyright &y& Elsevier]

Abstract: In this paper, we give some results related to interaction mechanism between the elements V such as antimony or phosphorus with the metal indium. We used both powerful spectroscopy methods the Auger electron spectroscopy (AES) and the electron energy loss spectroscopy (EELS) for which the spectra were recorded in direct mode N(E). The antimony was evaporated on pure In metal or on cleaned InP surface involving the In metal because of its cleaning by the argon ion bombardment at low energy 300eV. The antimony flow composed of Sb4 species arrived with a thermal energy on the In metal surface. Such an energy was sufficient to their diffusion into the In matrix because of the low melting point of In metal (123°C). A nucleation phenomenon occurred between Sb4 and the In metal to form small islands of antimony metal in bulk. Further antimony evaporation enabled to increase the size of these islands towards the surface. However, the antimony evaporated on cleaned InP reacted chemically with the In metal distributed on the InP surface to form a thin layer of InSb. The inner stoichiometric layers of InP and the size of Sb4 species and also the stability of InP versus the temperature impeded the interdiffusion phenomenon of antimony to occur deeply into the InP matrix. The InSb layer played the role to stabilise the surface of the InP compound versus the heating at 450°C and the electron irradiation of 4KeV energy. But, the phosphorus evaporation on In metal or on cleaned InP led to form chemical bonds InP. The phosphorus flow included chemical species P and P2 with a thermal energy able to stimulate the chemical reactivity process between indium and phosphorus to form the InP compound. [Copyright &y& Elsevier]

Abstract: This paper presents results of the effect of electron beam irradiation under UHV conditions on InGaAs/GaAs and GaAsN/GaAs systems using Auger electron spectroscopy (AES) and the electron energy loss spectroscopy (EELS) as surface analytical techniques. The ternary compounds In0.53Ga0.47As and In0.2Ga0.8As were irradiated by an electron beam under identical conditions (5KeV; 10−3 Acm−2; for 60min). The results showed that the compound In0.53Ga0.47As was stable under electron irradiation whereas changes in the Auger signal In–M45N45N45 revealed that the electron beam had a significant effect on the compound In0.2Ga0.8As. GaAsN growth at 590°C on GaAs is believed to produce a surface containing defects that is chemically unstable when bombarded by electrons. It was found that heating this compound at 730°C stabilised the surface, protecting it from the effect of electron irradiation. [Copyright &y& Elsevier]

Auger electron spectroscopy and electron energy loss spectroscopy (EELS) have been used to characterize the oxide InPO4 whose thickness is about 10 A˚ as grown on the substrate InP (1 0 0). The behaviour of the surface was studied following either electron irradiation or heating in UHV. The high sensitivity of the EELS, showed a structural change of the surface after irradiation with electrons of 5 keV energy, InPO4 being sensitive to the electron beam. However, this surface oxide appeared to be stable when heated in UHV at 450°C. [Copyright &y& Elsevier]

We have used Auger and electron energy loss spectroscopy to study the effect of temperature on InGaAs and InPO4 grown on InP. The thickness of InPO4 is of about 10 Å whereas that of InGaAs is of about 800 Å. InPO4 is of great interest because it protects InP from loss of stoichiometry when heated to 450 °C. The InGaAs system heated at 450 °C seems to be unstable; metallic indium appears on the surface in conjunction with formation of GaAs. [Copyright &y& Elsevier]

Abstract: The goal of this research is to highlight the effectiveness of associating the spectroscopic methods EELS and EPES in the study of thin film grown on substrates. We use the great sensitivity of the Electron Energy Loss Spectroscopy (EELS) and the Elastic Peak Electron Spectroscopy (EPES) to study native InPO4 oxide of thin thickness (10Å) grown on InP by UV/ozone oxidation. By varying the primary energy of the electron beam and the incidence angle, we give interesting results related to the chemical and the physical analyses of InPO4/InP system. These spectroscopic methods reveal the homogeneity of the chemical composition of InPO4 on the surface. Furthermore, the electron irradiation of InPO4/InP leads to the breaking of chemical bonds between the species of InPO4 and InP to form a new oxide In2O3 on the surface. We show that the heating of InPO4/InP at 450°C in UHV allows a good reconstruction of the surface with elimination of defects on the surface and at the interface. Thus, the surface becomes more stable to impede all oxidation processes due to the electron beam irradiation even for a time as long as 30min. [Copyright &y& Elsevier]

Abstract: The interaction of ions with matter plays an important role in the treatment of material surfaces. In this paper we study the effect of argon ion bombardment on the InSb surface in comparison with the InP one. The Ar+ ions, accelerated at low energy (300eV) lead to compositional and structural changes in InP and InSb compounds. The InP surface is more sensitive to Ar+ ions than that of InSb. These results are directly inferred from the qualitative Auger electron spectra (AES) and electron energy loss spectroscopy (EELS) analysis. However, these techniques alone do not allow us to determine with accuracy the disturbed depth in Ar+ ions of InP and InSb compounds. For this reason, we combine AES and EELS with the simulation method TRIM (transport and range of ions in matter) to show the mechanism of interaction between the ions and the InP or InSb and hence determine the disturbed depth as a function of Ar+ energy. [Copyright &y& Elsevier]

• Updated probabilistic models for the annual maximum wind speed and the ground snow load depth for Canada. • Treated thunderstorm and non-thunderstorm winds in reliability analysis separately. • Calibrated new design wind and snow load and load combination factors for Canadian practice. • Calibrated and recommended load scaling factors accounting for climate change effects for the National Building Code of Canada. In the present study, an updating of the probabilistic models used for calibrating the wind load, snow load and companion load factors for the National Building Code of Canada (NBCC) are presented. The update of probabilistic models for the extreme wind speed and ground snow depth is based on historical climatological data over Canadian sites. For the updating of the statistics of the extreme wind speed, the effect of mixed wind climate (i.e., thunderstorm winds and non-thunderstorm winds) is considered. Reliability analysis is carried out based on this update by considering different load combinations. The results indicate that, for an improved reliability consistency, the use of a high return period to specify the environmental loads and with a unit load factor is preferable to the use of 50 year return period and a load factor greater than one for structural design code making, if the coefficient of variation of the extreme climatological elements is spatially varying. Most importantly, based on these findings and the results from the climate change modelling results, sets of load scaling factors accounting for climate change effects are calibrated for different regions in Canada. Both the use of the target reliability index for a 50-year design working life as well as of the target minimum required annual reliability index within each of the 50-year design working life are considered for the reliability-based calibration. Specific recommendations on the load and companion load factors are suggested for a future edition of NBCC. [ABSTRACT FROM AUTHOR]