Measurements of the flow and thermal characteristics of turbulent jets in cross flow

An experimental investigation of the flow, turbulence, and thermal characteristics of heated, cooled, and isothermal turbulent jets in cross flow is reported. The experiments were carried out in a water channel facility of the recirculation type. Hot or cold water was injected verically upward from a circular pipe located near the channel bottom to the cross-flowing stream in the channel. Hot- and cold-film anemometers along with appropriate linearizers, bridges, filters, and probes were used. A new signal analysis method was developed for resolving the complex three-dimensional structure of the mean turbulent flow field resulting from the interaction between the free stream and the jet. A rotatable probe technique was used to measure the size components of the Reynolds stress tensor in isothermal flows of any turbulence intensity. New expressions that correct for the temperature contamination of the velocity signals in nonisothermal flows were developed for both the linearized and unlinearized anemometer responses;Mean velocity and turbulence intensity data were obtained for the isothermal jet at jet-to-free stream velocity ratios of 2, 4, and 6 both in and outside the jet plane of symmetry. For the latter velocity ratio, a detailed analysis was carried out to reveal the details of the three-dimensional structure of the flow field. A similar analysis was made for the heated jet at a velocity ratio of 4. For this latter velocity ratio, the turbulent shear stresses, the turbulent RMS velocity fluctuations, the structural parameter, correlation coefficients, and the turbulent kinetic energy were obtained for the isothermal jet. Mean and RMS temperatures, on the other hand, were obtained for both heated and cooled jets. In the former case, velocity ratios of 1, 2, 4, and 7 were studied with a jet discharge temperature approximately 50(DEGREES)F to 75(DEGREES)F higher than the free stream temperature. In the latter case, velocity ratios of 1, 4, and 7 were employed with temperature differences of approximately -20(DEGREES)F and -50(DEGREES)F;The measurements reported in this study provide new information on the velocity, turbulence, and thermal field of turbulent jets in cross flow. These data should be useful for the development, improvement, and verification of better prediction methods and turbulence models for complex free shear flows

Morphology and taxonomy of the adult males of the family Pseudococcidae (Homoptera : Coccoidea)

Imperial Users onl

The dual education program in Egypt: a qualitative study on challenges and opportunities

The Mubarak Kohl Initiative – now called the Dual Education System is considered as one of the most successful intervention of active labor market programs (ALMPs) in Egypt. The Dual Education Program offers a unique type of education that includes on-the-job training. Students can learn, work and earn in addition to a guaranteed job opportunity upon graduation. The blue collar category is normally the poor people who suffer from a low social standard as well as low income. The Dual Education System mainly targets technical and vocational workers to promote their living standard. Technical and Vocational Education in Egypt occupies the least governmental attention in regards to its improvement and budget allocation. This thesis will give an overview on governmental expenditure on technical and vocational education in Egypt. Also, it will point out the importance of the Dual Education System initiative in promoting the vocational and technical professions in Egypt and providing better job opportunities for its graduates and how far this is actually accomplished in reality and the key behind the project\u27s sustainability. It will also point out the main lessons to be learnt from the Dual Education System, how it can be replicated by other interventions and how the program is evolving in its current scale-up phase. It will also show why preparatory students join the Dual Education System although they do not intend to continue in technical and vocational jobs

Low Complexity V-BLAST MIMO-OFDM Detector by Successive Iterations Reduction

V-BLAST detection method suffers large computational complexity due to its successive detection of symbols. In this paper, we propose a modified V-BLAST algorithm to decrease the computational complexity by reducing the number of detection iterations required in MIMO communication systems. We begin by showing the existence of a maximum number of iterations, beyond which, no significant improvement is obtained. We establish a criterion for the number of maximum effective iterations. We propose a modified algorithm that uses the measured SNR to dynamically set the number of iterations to achieve an acceptable bit-error rate. Then, we replace the feedback algorithm with an approximate linear function to reduce the complexity. Simulations show that significant reduction in computational complexity is achieved compared to the ordinary V-BLAST, while maintaining a good BER performance.Comment: 6 pages, 7 figures, 2 tables. The final publication is available at www.aece.r

Efficient and Privacy-Preserving Ride Sharing Organization for Transferable and Non-Transferable Services

Ride-sharing allows multiple persons to share their trips together in one vehicle instead of using multiple vehicles. This can reduce the number of vehicles in the street, which consequently can reduce air pollution, traffic congestion and transportation cost. However, a ride-sharing organization requires passengers to report sensitive location information about their trips to a trip organizing server (TOS) which creates a serious privacy issue. In addition, existing ride-sharing schemes are non-flexible, i.e., they require a driver and a rider to have exactly the same trip to share a ride. Moreover, they are non-scalable, i.e., inefficient if applied to large geographic areas. In this paper, we propose two efficient privacy-preserving ride-sharing organization schemes for Non-transferable Ride-sharing Services (NRS) and Transferable Ride-sharing Services (TRS). In the NRS scheme, a rider can share a ride from its source to destination with only one driver whereas, in TRS scheme, a rider can transfer between multiple drivers while en route until he reaches his destination. In both schemes, the ride-sharing area is divided into a number of small geographic areas, called cells, and each cell has a unique identifier. Each driver/rider should encrypt his trip's data and send an encrypted ride-sharing offer/request to the TOS. In NRS scheme, Bloom filters are used to compactly represent the trip information before encryption. Then, the TOS can measure the similarity between the encrypted trips data to organize shared rides without revealing either the users' identities or the location information. In TRS scheme, drivers report their encrypted routes, an then the TOS builds an encrypted directed graph that is passed to a modified version of Dijkstra's shortest path algorithm to search for an optimal path of rides that can achieve a set of preferences defined by the riders

Effect of dexamethasone on daily fetal movement, umbilical and middle cerebral arteries Doppler and cardiotocogram

Background: Preterm birth is a leading cause of perinatal death and disability and is an important public health problem globally. There is more work to be done regarding steroids effect, especially with the variations among demography and pathological conditions affecting mothers. The aim of this study was to investigate the effect of dexamethasone on healthy fetuses, observing the effects on MCA and UA Doppler velocity waveforms and cardiotocography, correlating them with fetal movement.Methods: This prospective cross-sectional study was conducted in Ain Shams University Maternity Hospital, starting from April 2020 till December 2020. One hundred and ten women was recruited for the study. All women undergo elective cesarean section before 39 weeks of gestation. UA and MCA Doppler values were taken; nonstress test was recorded and fetal movements were counted after a single course of dexamethasone.Results: Our results included decrease in MCA PI, decrease in foetal movement count on the second day of dexamethasone injection, increase of short-term variability and direct correlation between the MCA RI and UA PI with the fetal movements decrease on the 5th day of dexamethasone injection.Conclusions: There are definitely cardiovascular changes that occur after dexamethasone administration, presented by increase in MCA blood flow and increase in FHR short term variability.

Emancipatory Education between Literature and Cultural Studies

La tesi, seguendo il percorso suggerito dal titolo, si propone di costruire una base teorica, indagando, non solo nel contesto italiano ma anche a livello mondiale, la portata formativa ed educativa dell’insegnamento delle letterature contemporanee, soprattutto nelle lezioni di lingua, letteratura e traduzione. La tesi è divisa in quattro capitoli che vanno a mettere a fuoco parallelismi e traiettorie fra il profilo biografico, l’intellettuale e sociopolitico. Tale profilo costituisce il filo rosso della tesi, che mira a realizzare una mappatura delle principali tesi e pratiche delle figure prese in esame, con una particolare attenzione all’insegnamento della letteratura. Le figure di riferimento sono Gramsci, don Lorenzo Milani, Paulo Freire e Spivak. Di ognuna viene tracciato un profilo biografico, un panorama degli snodi principali delle singole posizioni in merito alla questione dell’educazione, aprendo poi la riflessione alle pratiche possibili da attuarsi nel contesto odierno.The thesis, following the path suggested by the title, aims to build a theoretical basis, investigating, not only in the Italian context but also at a global level, the formative and educational scope of the teaching of contemporary literature, especially in language, literature and translation lessons. The thesis is divided into four chapters that focus on parallels and trajectories which, intersecting the biographical, intellectual and socio-political dimensions, are questioned as a function of the production of a new formative and educational profile. This profile constitutes the red thread of the thesis, which aims to map the main theses and practices of the figures under consideration, with particular attention to the teaching of literature. The figures of reference are Gramsci, Don Lorenzo Milani, Paulo Freire and Spivak. A biographical profile is drawn for each one, a panorama of the main points of the individual positions on the issue of education, then opening reflection to possible practices to be implemented in today's context