Phase of flight identification in general aviation operations

Identifying phases of flight in General Aviation can help in identifying safety events, which are events which may result in the aircraft being in a hazardous state. Unlike commercial operations that have well-defined phases of flight such as taxi, takeoff, climb, cruise, descent, approach, and landing, GA missions have more hard-to-identify phases of flight. For example, pilot training missions can involve multiple “touch-and-go” maneuvers, which make it difficult to define a distinct cruise phase during the patterns. Here, we present an algorithm to automatically identifying phases of flight in GA. The method includes an algorithm to tailor the phase of flight identification for flights from different regions. We demonstrate our approach on 376 different flights from Cirrus SR20 and Cessna C172 aircraft equipped with a Garmin G1000 avionics system

Kinetic modeling of polyurethane pyrolysis using non-isothermal thermogravimetric analysis

International audienceThe pyrolysis of polyurethane was studied by dynamic thermogravimetry analysis (TGA). Thestudied polyurethane is used as organic binder in casting process to make sand cores and molds. Asemi-empirical model is presented that can be used to describe polyurethane pyrolysis occurringduring TGA experiments. This model assumes that the polyurethane is pyrolysed by severalparallel independent reactions. The kinetic parameters of polyurethane pyrolysis were evaluatedby fitting the model to the experimental data obtained by TGA over a wide variety of heatingrates. A nonlinear least-squares optimization method is employed in the fitting procedure. Ahybrid objectives based simultaneously on the mass (TG) and mass loss rate (DTG) curves hasbeen used in the least-squares method. The values of the activation energy obtained by the nonlinearfitting were then recalculated by the methods of Kissinger and Friedmand. Furthermore,the parameters obtained in the present paper were then compared with those reported in theliterature

A Sobolev Poincar\'e type inequality for integral varifolds

In this work a local inequality is provided which bounds the distance of an integral varifold from a multivalued plane (height) by its tilt and mean curvature. The bounds obtained for the exponents of the Lebesgue spaces involved are shown to be sharp.Comment: v1: 27 pages, no figures; v2: replaced citations of the author's dissertation by proofs, material of sections 1 and 3 reorganised, slightly more general results in section 2, some remarks, some discussion and some references added, 40 pages, no figure

Geothermal contribution to the energy mix of a heating network when using Aquifer Thermal Energy Storage: modeling and application to the Paris basin

International audienceAquifer Thermal Energy Storage (ATES) is a promising solution for reducing the time mismatch between energy production and demand in urban environments, and recent successful experiences suggest that technical issues can be overcome. The Paris area is a priori a favorable region, since there is locally a surplus of heat production during the summer, an appropriate geological reservoir and both existing and projected district heating networks. This article focuses on a remaining issue: estimating the geothermal contribution to the energy mix of a district heating network over time when using an ATES. This result would then enable estimating the fuel cost savings obtained by avoiding the consumption of expensive energies during the winter retrieval. This work considers an ATES made of two reversible wells reaching the Dogger aquifer and providing energy to a new low-temperature district heating network heating 7,500 housing-equivalents. Non-geothermal energy sources with fluctuating prices over time are used for winter peak demand and for summer heat storage. The temperature of brine unloading at the hot and cold wells is simulated and the adequacy of this geothermal system to meet the load is studied in order to evaluate the time dependent energy mix of the network. Results suggest that in average over the 30 years of operation, the ATES delivers 54 GWh per year to the heating system, i.e. a power of 9.5 MW during the 34 unloading winter weeks. The geothermal energy share in the energy mix is 70%, higher than the 50% possible with a conventional geothermal doublet. The ratio of energy delivered by the ATES divided by energy spent for storage reaches 143%, and is only slightly reduced to 137% when the cold storage is located on an existing cold plume created by past geothermal energy operations

Effect of Introduction of Female and Male Urine Pheromones on Estrous Cycle Length and Progestogen and Testosterone Metabolite Concentration in Captive Red River Hogs (Potamochoerus Porcus) in North American Zoos

Captive red river hogs (RRH) have variable reproductive success yet potential causes are unknown. We hypothesized that non-breeding females would cycle or cycle more regularly and non-breeding males with low libido would increase concentrations of fecal testosterone metabolites in response to urine pheromone exposure. Female estrous cycles and progestogen metabolite (P4) concentrations and male testosterone metabolite (T) concentrations were compared between: 1) proven-breeder pairs (control(C); male n=3; female n=4), 2) new pairs (new male(NM); male n=4; female n=4), and 3) pairs exposed to pheromones (pheromone(P); male n=3; female n=3). Fecal samples were collected 3-5 times per week for a year. P animals had baseline sampling (6 months), followed by 2.5 month exposure to sow urine, 2-4 week wash-out, and 2.5 month exposure to boar urine. Fecals were extracted and assayed for P4 and T with ELISAs. Results were assessed for normality with PROC GLM (SAS, Cary, N.C.) and non-normal data transformed with repeated measures ANOVA (P4/T) or one-way ANOVA (cycles). There was a trend for P female’s estrous cycle length to elongate (P baseline: 15.7 ± 1.5 days; P post-male: 19.3 ± 3.1 days; p=0.07) and for P male T concentrations to increase (+336.1±1.4 ng/g feces) in response to male urine pheromones. Pregnancies occurred in 2/3 C, 1/4 NM, with pseudopregnancy/pregnancy loss noted in 1/3 C and 2/3 NM females. The luteal phase P4 concentration for non-pregnant females was highest in P females and lowest in NM females (P: 3945.6 ± 158.3 ng/g feces; C: 3291.6 ± 196.3 ng/g feces; NM: 2884.5 ± 144.1 ng/g feces). Overall T concentration for males was highest in P males and lowest in NM males (P: 909.6 ± 365.3 ng/g feces; C: 427.5 ± 353.8 ng/g feces; NM: 325.4 ± 283.2 ng/g feces). A season and treatment interaction (p<0.0001) for males and females, and acyclicity of females from August-December suggest that season confounded the results. Females housed with pregnant females were acyclic or experienced pseudopregnancy/pregnancy loss, suggestive of female reproductive suppression. In conclusion, urine pheromones may manipulate reproduction in captive RRH and consideration of the number of female RRH in housing is warranted

Mélanges et documents - La Sociologie de M. Durkheim et l’Histoire des religions

La Revue de l’Histoire des Religions avait bien voulu me demander le compte rendu de deux ouvrages récents qui se réclament de la même méthode, tout en différant de valeur : Les formes élémentaires de la Religion par M. Émile Durkheim et The sociological value of Christianity par M. Georges Chatterton Hill. Il me sera permis d’en rattacher l’examen à un exposé général des vues professées par une école dont on peut rejeter les conclusions et même le point de départ, mais dont on doit reconnaît..