Analytical investigation of turbine erosion phenomena. Volume III - Effect of external variables on the erosion property of materials Interim technical report

Effect of external variables on erosion rates of turbine blade materials under impacting liquid drops and chemical dissolution of flowing liqui

GC-Recomposition-Olfactometry (GC-R) and multivariate study of three terpenoid compounds in the aroma profile of Angostura bitters.

Foods and beverage aroma results from multicomponent mixtures of volatile compounds present in the food that interact with olfactory receptors and produce a perceptual response in the brain. However, the perceptual interactions that occur when complex odor mixtures are combined are not well understood. Here we used Gas chromatography-Recomposition-Olfactometry (GC-R) to better understand the role that individual compounds have on the perceived sensory aroma of bitters. Bitters are the concentrated alcoholic extract of flavorful plant materials with a wide range of complex sensory and chemical aroma profiles that have not been extensively studied. Previously, we demonstrated that Angostura bitters are characterized by complex aroma attributes described as cola, ginger, orange peel, and black pepper and that the volatile composition of Angostura bitters is predominantly composed of terpenoids. Using GC-R to create in-instrument mixtures of the Angostura headspace extracts, the sensory attributes of Angostura extracts with linalool, α-terpinyl-acetate and caryophyllene omitted were evaluated. The omission experiments demonstrated direct and indirect effects of the individual compounds on the aroma attributes of Angostura bitters, through masking, additive, and synergistic interactions. Caryophyllene in particular, which was present in the headspace extracts at concentration only slightly above sensory threshold levels, had a large and unexpected impact on the sensory properties of the mixtures and may be most responsible for the aromas associated with the whole sample. The GC-R and statistical approaches used here provided valuable tools to reveal relationships among individual compounds and aroma attributes of foods that have not been currently theorized using existing analytical approaches

Indización, rezagos fiscales e inflación

This paper analyzes the dynamics of a model in which prices have inertia and, at the same time, inflation depends also on the fiscal deficit.

A Stochastic Continuous Time Model for Microgrid Energy Management

International audienceWe propose a novel stochastic control formulation for the microgrid energy management problem and extend previous works on continuous time rolling horizon strategy to uncertain demand. We modelize the demand dynamics with a stochastic differential equation. We decompose this dynamics into three terms: an average drift, a time-dependent mean-reversion term and a Brownian noise. We use BOCOPHJB for the numerical simulations. This optimal control toolbox implements a semi-Lagrangian scheme and handle the optimization of switching times required for the discrete on/off modes of the diesel generator. The scheme allows for an accurate modelling and is computationally cheap as long as the state dimension is small. As described in previous works, we use a trick to reduce the search of the optimal control values to six points. This increases the computation speed by several orders. We compare this new formulation with the deterministic control approach introduced in [1] using data from an isolated microgrid located in northern Chile

Long-term analysis of carbon dioxide and methane column-averaged mole fractions retrieved from SCIAMACHY

Carbon dioxide (CO<sub>2</sub>) and methane (CH<sub>4</sub>) are the two most important anthropogenic greenhouse gases contributing to global climate change. SCIAMACHY onboard ENVISAT (launch 2002) was the first and is now with TANSO onboard GOSAT (launch 2009) one of only two satellite instruments currently in space whose measurements are sensitive to CO<sub>2</sub> and CH<sub>4</sub> concentration changes in the lowest atmospheric layers where the variability due to sources and sinks is largest. <br><br> We present long-term SCIAMACHY retrievals (2003–2009) of column-averaged dry air mole fractions of both gases (denoted XCO<sub>2</sub> and XCH<sub>4</sub>) derived from absorption bands in the near-infrared/shortwave-infrared (NIR/SWIR) spectral region focusing on large-scale features. The results are obtained using an upgraded version (v2) of the retrieval algorithm WFM-DOAS including several improvements, while simultaneously maintaining its high processing speed. The retrieved mole fractions are compared to global model simulations (CarbonTracker XCO<sub>2</sub> and TM5 XCH<sub>4</sub>) being optimised by assimilating highly accurate surface measurements from the NOAA/ESRL network and taking the SCIAMACHY averaging kernels into account. The comparisons address seasonal variations and long-term characteristics. <br><br> The steady increase of atmospheric carbon dioxide primarily caused by the burning of fossil fuels can be clearly observed with SCIAMACHY globally. The retrieved global annual mean XCO<sub>2</sub> increase agrees with CarbonTracker within the error bars (1.80±0.13 ppm yr<sup>−1</sup> compared to 1.81±0.09 ppm yr<sup>−1</sup>). The amplitude of the XCO<sub>2</sub> seasonal cycle as retrieved by SCIAMACHY, which is 4.3±0.2 ppm for the Northern Hemisphere and 1.4±0.2 ppm for the Southern Hemisphere, is on average about 1 ppm larger than for CarbonTracker. <br><br> An investigation of the boreal forest carbon uptake during the growing season via the analysis of longitudinal gradients shows good agreement between SCIAMACHY and CarbonTracker concerning the overall magnitude of the gradients and their annual variations. The analysis includes a discussion of the relative uptake strengths of the Russian and North American boreal forest regions. <br><br> The retrieved XCH<sub>4</sub> results show that after years of stability, atmospheric methane has started to rise again in recent years which is consistent with surface measurements. The largest increase is observed for the tropics and northern mid- and high-latitudes amounting to about 7.5±1.5 ppb yr<sup>−1</sup> since 2007. Due care has been exercised to minimise the influence of detector degradation on the quantitative estimate of this anomaly

Extended family caring for children orphaned by AIDS: balancing essential work and caregiving in a high HIV prevalence nations.

While over 90 per cent of the 15 million children who have been orphaned by HIV/AIDS are cared for by family members, there is little information about whether adults can meet orphans' essential caregiving needs while working to economically survive. Using a survey we conducted in Botswana of 1033 working adults, we analyse the experience of adults who are caring for orphans. Over one-third of working adults were caring for orphans and many with few financial resources: 82% were living on household incomes below US$10 purchasing power parity adjusted per person per day. Because of their caregiving responsibilities, they were less able to supplement income with overtime, weekend, evening, or night work. At the same time caregiving responsibilities meant orphan caregivers spent fewer hours caring for their own children and other family members. Nearly half of orphan caregivers had difficulties meeting their children's needs, and nearly 75% weren't able to meet with children's teachers. Pay loss at work compounded the problems: One-quarter of orphan caregivers reported having to take unpaid leave to meet sick childcare needs and nearly half reported being absent from work for children's routine health care. This paper makes clear that if families are to provide adequate care for orphans while economically surviving there needs to be increases in social supports and improvements in working conditions