Systematic approach furthering confirmation measures of safety critical automotive systems

Different system elements are developed independently from diverse suppliers and teams before being integrated together into safety critical automotive systems such as steering or braking systems by a manufacturer. It must be guaranteed that, despite this independent development, the achievement of the safety requirements for the overall system can be demonstrated. The necessary agreements and the integration of the necessary safety information for the overall system generate higher extra costs. In order to reduce development time and cost, systematic reuse can be a solution to engineering the required artifacts. Reassessment represents an additional source of cost. Even small modifications of a system or exchanging a component after it has been certified necessitates a reassessment. The effort required for reassessment, in many cases reaches the original effort of certification for the complete system or even exceeds it. To minimize the effort and cost of a reassessment, this paper introduces a theoretical foundation of a model-based engineering approach to reuse a safety case and change only the modified parts. This paper presents a reusability framework to support the distributed development environment together with the different composition scenarios with respect to ISO26262. A further benefit of this approach is that for development of variants in product-line, the Safety assessment process can now be easily expressed and managed

The partial oxidation of methane over Pd/Al2O3 catalyst nanoparticles studied in-situ by near ambient-pressure x-ray photoelectron spectroscopy

Near ambient-pressure X-ray photoelectron spectroscopy (NAP-XPS) is used to study the chemical state of methane oxidation catalysts in-situ. Al2O3{supported Pd catalysts are prepared with different particle sizes ranging from 4 nm to 10 nm. These catalysts were exposed to conditions similar to those used in the partial oxidation of methane (POM) to syn-gas and simultaneously monitored by NAP-XPS and mass spectrometry. NAP-XPS data show changes in the oxidation state of the palladium as the temperature in- creases, from metallic Pd0 to PdO, and back to Pd0. Mass spectrometry shows an increase in CO production whilst the Pd is in the oxide phase, and the metal is reduced back under presence of newly formed H2. A particle size effect is observed, such that CH4 conversion starts at lower temperatures with larger sized particles from 6 nm to 10 nm. We find that all nanoparticles begin CH4 conversion at lower temperatures than polycrystalline Pd foil

Metal dispersion, accessibility and catalytic activity in methane oxidation of mesoporous templated aluminosilica supported palladium

International audiencePalladium catalysts using templated mesostructured porous silicas and aluminosilicas of MCM-41 type as supports were synthesized with various metal loadings and particle sizes as well as different metal accessibilities to the reactants. The metal was deposited by reacting an aqueous solution of [Pd(NH3)4]2+ complexes with the support, the template of which was partially extracted. The evolution of the support characteristics was monitored at different steps of preparation using X-ray diffraction (XRD), N2 physisorption and transmission electron microscopy (TEM). Particle size and metal accessibility were evaluated combining information from XRD line broadening, TEM observations, UV–visible spectra and H2 uptakes. The PdO reducibility was investigated using temperature-programmed reduction (TPR). In the templated mesoporous aluminosilicate, 27Al-MAS-NMR revealed that Al3+ occupied mostly tetrahedral sites, a fraction of which adopted an octahedral environment in the presence of palladium. According to the light-off curves, the catalytic methane oxidation activity is enhanced in pure silica supports where partial pore wall collapse has occurred. In contrast, for aluminosilica supports the beneficial effect of Al3+ on metal dispersion and catalytic activity was counterbalanced by partial metal encapsulation. Optimizing palladium particle size and avoiding as much as possible metal encapsulation give rise to catalysts more active than the conventional alumina supported palladium catalysts

Accurate global potential energy surface for the H + OH+ collision

International audienceWe mapped the global three-dimensional potential energy surface (3D-PES) of the water cation at the MRCI/aug-cc-pV5Z including the basis set superposition (BSSE) correction. This PES covers the molecular region and the long ranges close to the H + OH+(X3Σ-), the O + H2 +(X2Σg +), and the hydrogen exchange channels. The quality of the PES is checked after comparison to previous experimental and theoretical results of the spectroscopic constants of H2O+( X̄2B1) and of the diatomic fragments, the vibronic spectrum, the dissociation energy, and the barrier to linearity for H2O+(X̄2B 1). Our data nicely approach those measured and computed previously. The long range parts reproduce quite well the diatomic potentials. In whole, a good agreement is found, which validates our 3D-PES

Correlation between physical properties and growth mechanism of In

Indium sulfide (In2S3) thin films were grown on ITO-coated glass substrate using the electrodeposition method. The effect of the deposition time on the structural, morphological, optical and electrical properties of the as-grown In2S3 thin films was studied. XRD spectra of the obtained films reveal the polycrystalline nature of (β-In2S3) with a tetragonal crystal structure along the (109) plane, and exhibit a sharp transition to the (0012) plane when the deposition time is extended beyond 20 min. Using atomic force microscope (AFM), the surface morphology shows a remarkable change in the grain size, thickness, and surface roughness when varying the deposition time. UV-VIS spectrophotometer show that the optical band gap values of In2S3 decrease from about 2.82 to 1.93 eV by extending the electrodeposition duration from 5 to 20 min. All films were found to have an n-type character with a lower electrical resistivity of about 1.8×10-3 Ω cm for films deposited at 20 min

Quantifying Food Loss and Waste in Saudi Arabia

Using the FAO model calculations proposed by Gustavsson et al. (2013) and FAO (2014), food loss and waste (FLW) is measured in Saudi Arabia with a special focus on wheat, rice, dates, poultry, vegetables, fruits, fish, and meat. Results show that the overall FLW rate is 33.1%, where the food loss rate is 14.2%, and the food waste rate is 18.9%. Acceding to the disaggregated results, we find that FLW rates are distributed as follows: 29.7% for wheat, 33.6% for rice, 21.4%, for dates 29.1% for poultry, 39.5% for vegetables, 39.6% for fruits, 33% for fish, and 31.3% for meat. The Sustainable Development Goal (SDG 12.3) target is to reduce the rates of food loss and waste by 50% in 2030, and to help achieve that goal, we employed a nonlinear optimisation simulation model with the objective function of reducing FLW by 50% over the period 2020–2030. Based on the findings achieved, recommendations are made to cover the various aspects of the whole food supply chain (FSC) and to aim at more efficiency and higher levels of productivity. Our findings have significant implications by estimating the FLW baseline indicator and providing the different stakeholders of FSC with the optimal actions to do to reduce FLW rates