Three-dimensional analysis of the Pratt and Whitney alternate design SSME fuel turbine

The three dimensional viscous time-mean flow in the Pratt and Whitney alternate design space shuttle main engine fuel turbine is simulated using the average passage Navier-Stokes equations. The migration of secondary flows generated by upstream blade rows and their effect on the performance of downstream blade rows is studied. The present simulation confirms that the flow in this two stage turbine is highly three dimensional and dominated by the tip leakage flow. The tip leakage vortex generated by the first blade persists through the second blade and adversely affects its performance. The greatest mixing of the inlet total temperature distortion occurs in the second vane and is due to the large leakage vortex generated by the upstream rotor. It is assumed that the predominant spanwise mixing mechanism in this low aspect ratio turbine is the radial transport due to the deterministically unsteady vortical flow generated by upstream blade rows. A by-product of the analysis is accurate pressure and heat loads for all blade rows under the influence of neighboring blade rows. These aero loads are useful for advanced structural analysis of the vanes and blades

Measurements of the unsteady flow field within the stator row of a transonic axial-flow fan. 1: Measurement and analysis technique

This two-part paper presents laser anemometer measurements of the unsteady velocity field within the stator row of a transonic axial-flow fan. The objective is to provide additional insight into unsteady blade-row interactions within high speed compressors which affect stage efficiency, energy transfer, and other design considerations. Part 1 describes the measurement and analysis techniques used for resolving the unsteady flow field features. The ensemble-average and variance of the measured velocities are used to identify the rotor wake generated and unresolved unsteadiness, respectively. (Rotor wake generated unsteadiness refers to the unsteadiness generated by the rotor wake velocity deficit and the term unresolved unsteadiness refers to all remaining contributions to unsteadiness such as vortex shedding, turbulence, mass flow fluctuations, etc.). A procedure for calculating auto and cross correlations of the rotor wake generated and unresolved unsteady velocity fluctuations is described. These unsteady-velocity correlations have significance since they also result from a decomposition of the Navier-Stokes equations. This decomposition of the Navier-Stokes equations resulting in the velocity correlations used to describe the unsteady velocity field will also be outlined in this paper

Urological procedures in Central Europe and the current reality based on the national registries of Czech Republic, Hungary, and Poland (2012 status)

INTRODUCTION: In recent years, the laparoscopic approach in oncologic urology seems more attractable to the surgeons. It is considered to have the same oncologic quality as open surgery, but is less invasive in patients. It is used widely in all of Europe, but with various frequency. The aim of the study was to present a various amount of oncourological procedures from three neighbouring countries - Poland, Czech Republic and Hungary. Prostatectomy, cystectomy, nephrectomy and tumorectomy (Nephron Sparing Procedures - NSS) were presented as a list of procedures prepared from the national registry. MATERIAL AND METHODS: The total amount of procedures was presented, as well as the LO (Lap to Open procedures) index, P/P (procedures/population) index, ratio of cystectomy/population, and cystectomy/TURBT. RESULTS: In the Czech Republic, the most complex procedures are performed (laparoscopic/robotic prostatectomy, NSS LAP, LAP nephrectomy) in the majority when analysing the country's population. In Hungary and Czech Republic, there are more laparoscopic/robotic radical prostatectomies performed, than open ones. In Poland the largest number of cystectomies is performed when analysing the country's population, but it is difficult to explain the much higher ratio of 6.57 TUR/one cystectomy. In the Czech Republic this procedure is performed in almost one quarter of the patients (23.36%). Interestingly, in Hungary the cystectomy with pouch creation is performed in about 67.65% cases. The highest reimbursement for surgical procedure is present in the Czech Republic with approximately 20-40% more than when compared to Poland or Hungary. CONCLUSIONS: The definitive leader in Central Europe (based on the national registry) is the Czech Republic, where the most complex procedures are performed (laparoscopic/robotic prostatectomy, NSS LAP, LAP nephrectomy) in biggest amounts when analysing the country's population. Explanation of such circumstances, can be the higher reimbursement rate for surgical procedure in this country

Effects of photoperiod on boll weevil (Coleoptera: Curculionidae) development, survival, and reproduction

Effects of photoperiod on development, survival, feeding, and oviposition of boll weevils,Anthonomus grandis grandis Boheman, were assessed under five different photophases (24, 14, 12, 10, and 0 h) at a constant 27°C temperature and 65% RH in the laboratory. Analyses of our results detected positive relationships between photoperiod and puncturing (mean numbers of oviposition and feeding punctures per day), and oviposition (oviposition punctures/oviposition+feeding punctures) activities, and the proportion of squares attacked by boll weevil females. When boll weevil females developed in light:darkness cycles, they produced a significantly higher percentage of eggs developing to adulthood than those developed in 24-h light or dark conditions. In long photoperiod (24:0 and 14:10 h), the number of female progeny was significantly higher and their development time was significantly shorter than those developed in short photoperiod (0:24 and 10:14 h). Lifetime oviposition was significantly highest at 12- and 14-h photophase, lowest at 0- and 10-h photophase, and intermediate at 24 h of light. Life table calculations indicated that boll weevil populations developed in a photoperiod of 14:10 and 12:12 (L:D) h will increase an average of two-fold each generation (Ro) compared with boll weevils developed in 24:0- and 10:14-h photoperiods and 15-fold compared with those at 0:24 h. Knowledge of the photoperiod-dependent population growth potential is critical for understanding population dynamics to better develop sampling protocols and timing insecticide applications

Ultrafast proton coupled electron transfer (PCET) dynamics in 9-anthranol-aliphatic amine system

Femtosecond infrared absorption studies strongly suggest that photoexcited 9-anthranol takes part in an ultrafast electron transfer (ET) reaction in electron-donating triethylamine solvent, but that ultrafast proton coupled electron transfer (PCET) occurs in diethylamine solvent

Social Welfare in One-Sided Matching Mechanisms

We study the Price of Anarchy of mechanisms for the well-known problem of one-sided matching, or house allocation, with respect to the social welfare objective. We consider both ordinal mechanisms, where agents submit preference lists over the items, and cardinal mechanisms, where agents may submit numerical values for the items being allocated. We present a general lower bound of $\Omega(\sqrt{n})$ on the Price of Anarchy, which applies to all mechanisms. We show that two well-known mechanisms, Probabilistic Serial, and Random Priority, achieve a matching upper bound. We extend our lower bound to the Price of Stability of a large class of mechanisms that satisfy a common proportionality property, and show stronger bounds on the Price of Anarchy of all deterministic mechanisms

Gaussian limits for multidimensional random sequential packing at saturation (extended version)

Consider the random sequential packing model with infinite input and in any dimension. When the input consists of non-zero volume convex solids we show that the total number of solids accepted over cubes of volume $\lambda$ is asymptotically normal as $\lambda \to \infty$. We provide a rate of approximation to the normal and show that the finite dimensional distributions of the packing measures converge to those of a mean zero generalized Gaussian field. The method of proof involves showing that the collection of accepted solids satisfies the weak spatial dependence condition known as stabilization.Comment: 31 page

Overview of experimental critical point search

The existence and location of the QCD critical point is an object of vivid experimental and theoretical studies. Rich and beautiful data recorded by experiments at SPS and RHIC allow for a systematic search for the critical point - the search for a non-monotonic dependence of various correlation and fluctuation observables on collision energy and size of colliding nuclei.Comment: The 18th International Conference on Strangeness in Quark Matter (SQM 2019) proceedings, 8 pages, 8 figure

KATANA - a charge-sensitive triggering system for the Sπ\piRIT experiment

KATANA - the Krakow Array for Triggering with Amplitude discrimiNAtion - has been built and used as a trigger and veto detector for the S$\pi$RIT TPC at RIKEN. Its construction allows operating in magnetic field and providing fast response for ionizing particles, giving the approximate forward multiplicity and charge information. Depending on this information, trigger and veto signals are generated. The article presents performance of the detector and details of its construction. A simple phenomenological parametrization of the number of emitted scintillation photons in plastic scintillator is proposed. The effect of the light output deterioration in the plastic scintillator due to the in-beam irradiation is discussed.Comment: 14 pages, 11 figure