Analyse de l'écoulement dans la roue d'une turbine hydraulique axiale de type hélice : prise en considération du jeu de bout d'aube

Ce travail de mémoire présente la modélisation numérique et l'analyse de l'écoulement dans un seul passage de la roue d'une turbine hydraulique axiale de type hélice à l'aide du logiciel ANS YS CFX 11.0. Une approche Reynolds Averaged Navier-Stokes (RANS), basé sur le modèle Shear Stress Transport (SST), a été utilisée pour modéliser numériquement l'écoulement. Les simulations prennent en considération le jeu à l'extrémité des aubes. Souvent, le jeu est omis dans les simulations numériques dans les roues de turbines hydrauliques. Cependant, il donne lieu à l'écoulement de fuite interne et autres phénomènes turbulents, tel que le tourbillon de bout d'aube. La comparaison des simulations avec les mesures expérimentales réalisées dans la roue du modèle réduit de la turbine hélice démontrent que l'inclusion du jeu dans les simulations est essentielle pour mieux représenter les caractéristiques réelles de l'écoulement dans la roue de la turbine hélice et ainsi améliorer la prédiction de la performance de la roue d'une turbine hydraulique axiale

Gestión de residuos sólidos y la calidad ambiental de los pobladores del distrito de San Antonio – Lima, 2020

El presente trabajo de investigación, tuvo como objetivo general medir la relación que tiene la gestión de residuos sólidos y la calidad ambiental de los pobladores del distrito de San Antonio- Lima .2020. Así mismo, el trabajo se desarrolló en base a la percepción de los residentes sobre el manejo de residuos sólidos y como afecta al medio ambiente. El trabajo presenta un enfoque cuantitativo, de diseño no experimental de corte transversal y de nivel descriptivo correlacional. Siendo 380 pobladores del distrito de san Antonio de Jicamarca Anexo 22, la unidad de muestreo. Mismas que fueron encuestados por los dos instrumentos (cuestionarios) que sirvieron para medir cada variable y dimensión. Los resultados obtenidos muestran que existe una relación directa y significativa entre la gestión de residuos sólidos y la calidad ambiental. Esto se refleja en el coeficiente de correlación Rho de Spearman de 0.892

Results for the 2023 VIMS Industry Cooperative Surveys of the Mid-Atlantic Bight and Georges Bank Scallop Resource Areas

The Virginia Institute of Marine Science (VIMS) conducted high resolution sea scallop dredge surveys of the Mid-Atlantic Bight (MAB) and Georges Bank (GB) scallop resource areas during May–July 2023

Sistema Informático Web de Control de Eventos para el Centro de Convenciones del Hotel Chavín de Barranca, 2019

La presente tesis, tuvo por objetivo el desarrollo de un sistema informático web para el control de eventos en el Hotel Chavín de la provincia de Barranca, el motivo que nos inspiro para realizar este proyecto fue las necesidades específicas del negocio y ayudar a la difusión de su trabajo y razón social. La metodología del trabajo de acuerdo a la orientación de la investigación, es de tipo aplicada, de acuerdo a la técnica de contrastación, es de carácter descriptivo. No experimental de corte transversal. Se aplico la metodología RUP para la construcción de los diagramas de casos de usos para tener un mejor análisis del software, la base de datos está hecho con el programa gestor de base de datos MySQL, y lenguaje de programación PHP. Los resultados obtenidos en el presente informe, es el desarrollo de un sistema informático web para el control de eventos en el Hotel Chavín de la provincia de Barranca, la cual realiza el registro de diversos eventos y participantes, así como también los pagos de manera virtual.Tesi

Dual-Blind Deconvolution for Overlaid Radar-Communications Systems

The increasingly crowded spectrum has spurred the design of joint radar-communications systems that share hardware resources and efficiently use the radio frequency spectrum. We study a general spectral coexistence scenario, wherein the channels and transmit signals of both radar and communications systems are unknown at the receiver. In this dual-blind deconvolution (DBD) problem, a common receiver admits a multi-carrier wireless communications signal that is overlaid with the radar signal reflected off multiple targets. The communications and radar channels are represented by continuous-valued range-time and Doppler velocities of multiple transmission paths and multiple targets. We exploit the sparsity of both channels to solve the highly ill-posed DBD problem by casting it into a sum of multivariate atomic norms (SoMAN) minimization. We devise a semidefinite program to estimate the unknown target and communications parameters using the theories of positive-hyperoctant trigonometric polynomials (PhTP). Our theoretical analyses show that the minimum number of samples required for near-perfect recovery is dependent on the logarithm of the maximum of number of radar targets and communications paths rather than their sum. We show that our SoMAN method and PhTP formulations are also applicable to more general scenarios such as unsynchronized transmission, the presence of noise, and multiple emitters. Numerical experiments demonstrate great performance enhancements during parameter recovery under different scenarios.Comment: 26 pages, 13 figures, 1 tabl

Multi-Antenna Dual-Blind Deconvolution for Joint Radar-Communications via SoMAN Minimization

Joint radar-communications (JRC) has emerged as a promising technology for efficiently using the limited electromagnetic spectrum. In JRC applications such as secure military receivers, often the radar and communications signals are overlaid in the received signal. In these passive listening outposts, the signals and channels of both radar and communications are unknown to the receiver. The ill-posed problem of recovering all signal and channel parameters from the overlaid signal is terms as dual-blind deconvolution (DBD). In this work, we investigate a more challenging version of DBD with a multi-antenna receiver. We model the radar and communications channels with a few (sparse) continuous-valued parameters such as time delays, Doppler velocities, and directions-of-arrival (DoAs). To solve this highly ill-posed DBD, we propose to minimize the sum of multivariate atomic norms (SoMAN) that depends on the unknown parameters. To this end, we devise an exact semidefinite program using theories of positive hyperoctant trigonometric polynomials (PhTP). Our theoretical analyses show that the minimum number of samples and antennas required for perfect recovery is logarithmically dependent on the maximum of the number of radar targets and communications paths rather than their sum. We show that our approach is easily generalized to include several practical issues such as gain/phase errors and additive noise. Numerical experiments show the exact parameter recovery for different JRCComment: 40 pages, 6 figures. arXiv admin note: text overlap with arXiv:2208.0438

Factor Graph Processing for Dual-Blind Deconvolution at ISAC Receiver

Integrated sensing and communications (ISAC) systems have gained significant interest because of their ability to jointly and efficiently access, utilize, and manage the scarce electromagnetic spectrum. The co-existence approach toward ISAC focuses on the receiver processing of overlaid radar and communications signals coming from independent transmitters. A specific ISAC coexistence problem is dual-blind deconvolution (DBD), wherein the transmit signals and channels of both radar and communications are unknown to the receiver. Prior DBD works ignore the evolution of the signal model over time. In this work, we consider a dynamic DBD scenario using a linear state space model (LSSM) such that, apart from the transmit signals and channels of both systems, the LSSM parameters are also unknown. We employ a factor graph representation to model these unknown variables. We avoid the conventional matrix inversion approach to estimate the unknown variables by using an efficient expectation-maximization algorithm, where each iteration employs a Gaussian message passing over the factor graph structure. Numerical experiments demonstrate the accurate estimation of radar and communications channels, including in the presence of noise.Comment: 13 pages, 4 figure