143 research outputs found
Plantar Fasciitis: Platelet Rich Plasma vs. Corticosteroid injection
https://openriver.winona.edu/urc2018/1114/thumbnail.jp
VCE test bed engine for supersonic cruise research
Various design concepts for a variable cycle engine applicable to a supersonic, mixed mission propulsion system which would combine the merits of a turbofan at subsonic operating conditions with those of a turbojet for supersonic operating conditions are briefly examined. In particular the integration of the variable area bypass injector with the core driven (aft fan block) fan stage is discussed and the technical benefits of the configuration are summarized
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A FRAMEWORK AND ANALYTICAL APPROACH TO EVALUATE ALTERNATIVE VEHICLE MILES TRAVELED (VMT) FEE SYSTEMS
Since the fuel tax is a dwindling source of revenue, states need to find alternative funding sources. A vehicle miles traveled (VMT) fee has received serious consideration from a number of states and the federal government. What is missing from the VMT fee consideration is a framework for developing VMT fee systems and an analytical approach with which to study how well a proposed system conforms to the policies promulgated in the framework. This research strives to fill that void. The framework developed presents five areas of importance in VMT fee systems: 1. Revenue sufficiency; 2. Revenue stability; 3. Environmental Justice; 4. Low implementation cost; and 5. Security and privacy preservation. The analytical approach consists of two methods: 1. Use of NPV in order to evaluate the cost/benefit position of a proposed VMT fee system with respect to monetary and non-monetary but monetizable aspects; and 2. Use of an Index to evaluate all other aspects. To demonstrate the application of the framework and analytical approach, four VMT system designs were formulated, analyzed, and then compared to each other and to the fuel tax. The four VMT fee system designs are: 1. Alternative A where the total annual VMT is determined at the state inspection and charged for those miles; 2. Alternative B where the out-of-state VMT is deducted from the total annual VMT as determined at the annual state inspection and the fee charged for in-state VMT only; 3. Alternative C where a fee matrix is applied to GPS reported trip data so that fees may vary based on time and locale; and 4. Alternative D where there is a strategic implementation of Alternatives A, B, and C in that order and with two years separating the implementations. If added revenue is the main goal, then Alternative A is the best choice by being the lowest cost. If added revenue and the provision of a better strategy for alleviating such conditions as congestion, noise or air pollution or charging for higher quality roadways, then Alternatives C or D is the best fit. Alternative B performs best as a stepping-stone in Alternative D. All alternatives have better revenue sufficiency and stability than the fuel tax. The fuel tax exceeds all alternatives with respect to security and privacy preservation since no data, personal or otherwise, is recorded. Since security and privacy preservation are considered the weakest aspects of most VMT fee collection systems, added attention must be applied to incorporating design elements that cover aspects where breaches are possible such as in any data transmission, any computational and database processing, and billing/payment functions. The next step beyond this work is to study the construction of the fee matrix and exercise its use either in simulation or with actual data as collected by a stateâs department of transportation
Quand la politique change de scÚne : une analyse de la construction de l'identité discursive d'acteurs politiques à Tout le monde en parle
Analyse du refroidissement par film de la paroi de bout de pales d'une turbine en céramique à configuration renversée
Lâaugmentation de lâefficaciteÌ des turbines fonctionnant sur un cycle de Brayton reÌcupeÌreÌ passe par lâaugmentation de la tempeÌrature des gaz dâadmission. Cependant, les pales meÌtalliques doivent eÌtre massivement refroidies afin de supporter des tempeÌratures deÌpassant les 1600 K. Une nouvelle configuration utilisant des pales en ceÌramiques supporteÌes par une jante de composite et un moyeu flexible supporte des tempeÌratures de plus de 1600 K sans refroidir les pales. La configuration maintient les pales en compression durant la rotation de la turbine eÌvitant le bris de la ceÌramique lorsque soumise aÌ la tension. La jante de composite ne doit pas deÌpasser 600 K, neÌcessitant un systeÌme de refroidissement. Lâutilisation dâun refroidissement par film sur la paroi de bout de pales permet de reÌduire de 30 % le flux thermique traversant la paroi. Dans une configuration classique dâune turbine, les pales ne sont pas supporteÌes par leur bout, faisant en sorte quâaucune recherche ne porte sur le refroidissement par film de la paroi de bout de pales. Les multiples recherches faites sur le refroidissement par film des diffeÌrentes composantes dâune turbine montrent que la rotation de la turbine et la courbure des surfaces aÌ proteÌger influence lâefficaciteÌ du refroidissement par film.
Ce projet de maitrise vise aÌ expliquer comment le champ centrifuge creÌeÌ par la rotation de la turbine et la courbure de la paroi de bout de pales affectent le refroidissement par film. Une analyse de stabiliteÌ de gaz stratifieÌs, confineÌs entre deux parois et ayant une injection de gaz aÌ lâune des parois explique theÌoriquement comment la vitesse des gaz, le champ centrifuge et la vitesse dâinjection influencent la stabiliteÌ des gaz stratifieÌs. Le champ centrifuge augmente la plage de longueur dâonde de perturbations que peut toleÌrer le systeÌme sans eÌtre deÌstabiliseÌ, alors quâune diffeÌrence de vitesse entre les gaz deÌstabilise le systeÌme. La vitesse dâinjection doit eÌtre reÌduite au minimum puisquâelle deÌstabilise le systeÌme. Les reÌsultats de cette analyse ont eÌteÌ veÌrifieÌs expeÌrimentalement dans un canal courbeÌ. Les tests montrent que lâinjection normale aÌ lâeÌcoulement ne permet pas de stratifier deux gaz, alors quâune injection paralleÌle entraine une stratification qui prend plus de 37 aÌ se meÌlanger, soit plus du double de la longueur du rotor de la turbine eÌtudieÌe dans ce projet. Cependant, en raison du couplage entre la vitesse des gaz et le champ centrifuge quâimpose un canal courbeÌ, il est impossible dâobserver lâeffet du champ centrifuge et de la diffeÌrence de vitesse entre les gaz indeÌpendamment, indiquant la neÌcessiteÌ de concevoir un banc dâessai rotatif pour de futurs tests. Une analyse thermique du refroidissement par film de la paroi de bout de pales relie le flux thermique traversant la paroi au deÌbit massique de gaz de refroidissement et aÌ la tempeÌrature de la paroi. Cette analyse, fait le lien entre le refroidissement par film et le refroidissement par ailettes seÌparant la jante de composite de la paroi de bout de pales
Ăvaluation du risque pour la santĂ© publique associĂ© Ă l'intrusion en rĂ©seau de distribution suite Ă une baisse de pression transitoire
RĂSUMĂ La qualitĂ© de lâeau potable dĂ©livrĂ©e aux citoyens dĂ©pend bien sĂ»r de tous les efforts investis au niveau du traitement de lâeau brute, mais aussi de lâintĂ©gritĂ© du rĂ©seau de distribution. Bien que la municipalitĂ© Ă l'Ă©tude respecte tous les rĂšglements en matiĂšre de qualitĂ© de lâeau potable, une frĂ©quence de 20 Ă 30% supĂ©rieure de maladies gastrointestinales a Ă©tĂ© observĂ©e chez les citoyens consommant de lâeau du robinet, ayant sĂ©journĂ© dans le rĂ©seau de distribution, par rapport Ă ceux buvant de lâeau embouteillĂ©e Ă la sortie de lâusine de traitement alimentant ce mĂȘme rĂ©seau (Payment et al. 1997). Selon certains auteurs (Kirmeyer et al. 2001b, National Research Council of the National Academies 2006), les rĂ©parations de conduites et les Ă©pisodes de contamination transitoire constituent des voies dâentrĂ©e d'eau extĂ©rieure dans le rĂ©seau Ă risque Ă©levĂ©. Une dĂ©tĂ©rioration du signal Ă©lectrique Ă lâusine de production dâeau potable ou Ă un poste de surpression peut provoquer un arrĂȘt momentanĂ© des pompes en fonction, gĂ©nĂ©rant une onde de basses pressions, qui se propage dans le rĂ©seau et peut causer des pressions transitoires nĂ©gatives dans les rĂ©gions plus Ă©levĂ©es. De lâeau non traitĂ©e, provenant de la nappe phrĂ©atique peu profonde ou dâun Ă©gout/aqueduc fuyant, peut alors pĂ©nĂ©trer le rĂ©seau par lâintermĂ©diaire des fissures, des joints desserrĂ©s, et autres lieux de fuite. Lorsque la pression devient nĂ©gative, les ventouses s'actionnent en aspirant de l'air extĂ©rieur dans les conduites d'eau potable. Si ces ventouses sont submergĂ©es par de l'eau de ruissellement et/ou de l'eau souterraine inondant plusieurs chambres, c'est cette eau non traitĂ©e qui sera aspirĂ©e dans le rĂ©seau d'eau potable. Puisque des indicateurs de contamination fĂ©cale et des virus entĂ©riques ont Ă©tĂ© dĂ©tectĂ©s dans le sol, lâeau de tranchĂ©es et des chambres de vannes inondĂ©es (Karim et al. 2003, Besner et al. 2010), lâintrusion dans le rĂ©seau de l'eau se trouvant dans les environs dâune conduite ou dans une chambre de vanne Ă air prĂ©sente un risque de contamination.----------ABSTRACT Drinking water quality at the tap depends obviously upon the efforts committed at the treatment stage, but also upon the physical and hydraulic integrity of the distribution system. Although all drinking water standards were met by the studied distribution system, a 20 to 30% excess risk of gastrointestinal illnesses was associated with the consumption of tap water which travelled and aged in the distribution system, as compared with the consumption of drinking water bottled at the outlet of the treatment plant (Payment et al. 1997). Main repairs and transient contamination events are considered high-risk pathways for external water to enter the system (Kirmeyer et al. 2001b, National Research Council of the National Academies 2006). The deterioration of the electric signal at the water treatment plant or at the booster station can result in a pump trip, which will result in a low pressure wave. This downsurge wave will travel in the distribution system and may cause negative pressures in elevated areas. Under low or negative pressure conditions, untreated water originating from the shallow water table or a leaking sewer/water main can enter the distribution system pipes through cracks, loose fittings, corrosion holes, and other leakage orifices. When the pressure becomes negative, air vacuum valves are activated: they begin aspirating external air into water mains. If the outlet orifice of air vacuum valves is submerged by urban runoff water and/or groundwater flooding their valve vault, this untreated external water will be drawn into the drinking water distribution system. As indicators of fecal contamination have been detected in water main trenches and in flooded vaults (Karim et al. 2003, Besner et al. 2010), intrusion of such external water exposes the distribution system to a contamination risk
Negative pressures in full-scale distribution system: field investigation, modelling, estimation of intrusion volumes and risk for public health
International audienceVarious investigations encompassing microbial characterization of external sources of contamination (soil and trenchwater surrounding water mains, flooded air-valve vaults), field pressure monitoring, and hydraulic and transient analyses were conducted in the same distribution system where two epidemiological studies showing an increase in gastrointestinal illness for people drinking tap water were conducted in the 1990's. Interesting results include the detection of microorganisms indicators of fecal contamination in all external sources investigated but at a higher frequency in the water from flooded air-valve vaults, and the recording of 18 negative pressure events in the distribution system during a 17-month monitoring period. Transient analysis of this large and complex distribution system was challenging and highlighted the need to consider field pressure data in the process
Using nodal infection risks to guide interventions following accidental intrusion due to sustained low pressure events in a drinking water distribution system
Improving the risk models to include the possible infection risk linked to pathogen intrusion
into distribution systems during pressure-deficient conditions (PDCs) is essential. The objective of the
present study was to assess the public health impact of accidental intrusion through leakage points in
a full-scale water distribution system by coupling a quantitative microbial risk assessment (QMRA)
model with water quality calculations based on pressure-driven hydraulic analysis. The impacts on
the infection risk of different concentrations of Cryptosporidium in raw sewage (minimum, geometric
mean, mean, and maximum) and various durations of intrusion/PDCs (24 h, 10 h, and 1 h) were
investigated. For each scenario, 200 runs of Monte Carlo simulations were carried out to assess the
uncertainty associated with the consumersâ behavioral variability. By increasing the concentrations
of Cryptosporidium in raw sewage from 1 to 560 oocysts/L for a 24-h intrusion, or by increasing the
duration of intrusion from 1 to 24 h, with a constant concentration (560 oocysts/L), the simulated
number of infected people was increased by 235-fold and 17-fold, respectively. On the first day of the
1-h PDCs/intrusion scenario, a 65% decrease in the number of infected people was observed when
supposing no drinking water withdrawals during low-pressure conditions at nodes with low demand
available (<5%) compared to no demand. Besides assessing the event risk for an intrusion scenario,
defined as four days of observation, the daily number of infected people and nodal risk were also
modeled on diïżœerent days, including during and after intrusion days. The results indicate that, for
the case of a 1-h intrusion, delaying the start of the necessary preventive/corrective actions for 5 h
after the beginning of the intrusion may result in the infection of up to 71 people
Load-bearing in cortical bone microstructure: Selective stiffening and heterogeneous strain distribution at the lamellar level
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