Frequency response of an axial-flow compressor exposed to inlet pressure perturbations

Experimental results of a series of engine tests designed to obtain the stage dynamics of an eight-stage axial-flow compressor over the frequency range of 0.5 to 200 hertz are presented. The total pressure at the compressor face was varied by means of a secondary air jet system installed in the engine inlet and positioned to oppose the primary airflow. Total-pressure probes located at each compressor stage were used to obtain the frequency response of each compressor-stage total pressure to the average compressor-inlet total pressure. The engine operating conditions were chosen to illustrate the effects of changing the rotor speed, changing the exhaust nozzle area, and isolating the compressor discharge pressure perturbations from the fuel control and hence, the fuel flow

Study of turbojet combustor dynamics using sweep-frequency data

Sweep frequency nozzle pressure oscillation effects on turbojet combustor dynamic

Evaluating Interactive Visualization of Multidimensional Data Projection with Feature Transformation

There has been extensive research on dimensionality reduction techniques. While these make it possible to present visually the high-dimensional data in 2D or 3D, it remains a challenge for users to make sense of such projected data. Recently, interactive techniques, such as Feature Transformation, have been introduced to address this. This paper describes a user study that was designed to understand how the feature transformation techniques affect user’s understanding of multi-dimensional data visualisation. It was compared with the traditional dimension reduction techniques, both unsupervised (PCA) and supervised (MCML). Thirty-one participants were recruited to detect visual clusters and outliers using visualisations produced by these techniques. Six different datasets with a range of dimensionality and data size were used in the experiment. Five of these are benchmark datasets, which makes it possible to compare with other studies using the same datasets. Both task accuracy and completion time were recorded for comparison. The results show that there is a strong case for the feature transformation technique. Participants performed best with the visualisations produced with high-level feature transformation, in terms of both accuracy and completion time. The improvements over other techniques are substantial, particularly in the case of the accuracy of the clustering task. However, visualising data with very high dimensionality (i.e., greater than 100 dimensions) remains a challenge

Overlap Removal of Dimensionality Reduction Scatterplot Layouts

Dimensionality Reduction (DR) scatterplot layouts have become a ubiquitous visualization tool for analyzing multidimensional data items with presence in different areas. Despite its popularity, scatterplots suffer from occlusion, especially when markers convey information, making it troublesome for users to estimate items' groups' sizes and, more importantly, potentially obfuscating critical items for the analysis under execution. Different strategies have been devised to address this issue, either producing overlap-free layouts, lacking the powerful capabilities of contemporary DR techniques in uncover interesting data patterns, or eliminating overlaps as a post-processing strategy. Despite the good results of post-processing techniques, the best methods typically expand or distort the scatterplot area, thus reducing markers' size (sometimes) to unreadable dimensions, defeating the purpose of removing overlaps. This paper presents a novel post-processing strategy to remove DR layouts' overlaps that faithfully preserves the original layout's characteristics and markers' sizes. We show that the proposed strategy surpasses the state-of-the-art in overlap removal through an extensive comparative evaluation considering multiple different metrics while it is 2 or 3 orders of magnitude faster for large datasets.Comment: 11 pages and 9 figure

A 2012-es év a húszéves hazai felnőttszív-transzplantáció sikeréve - és ami mögötte van

The Hungarian adult heart transplant program, which started in 1992, has changed gradually in the past 20 years. After the early enthusiasm of the first cases it changed significantly and it became an organized programme. However, low donation activity and moderate referral numbers to the national transplant waiting list slowed down the process therefore, heart transplant numbers did not fulfill expectations in the early years. After a moderate increase in 2007 transplant numbers have dropped again until recently when Hungary partially joined Eurotransplant network. Excess fundamental resources allocated to cardiac transplantation by health care professionals and reorganizing transplant coordination as well as logistics forced dramatic changes in clinical management. In 2011 and 2012 major structural changes had been made at Semmelweis University. The newly established transplant intensive care unit and the initiation of mechanical circulatory support and assist device programme increased transplant numbers by 131% compared to previous years, as well as it resulted an 86.63% 30-day survival rate, hence last year was the most successful year of cardiac transplantation ever. Orv. Hetil., 2013, 154, 863-867

The idea of wilderness and United States land use policy: American Transcendentalism, preservation, and conservation, 1835-1914.

This thesis examines how Early American environmental groups— Romantic Transcendentalists, Preservationists, and Conservationists— interpreted wilderness. The paper argues nineteenth-century Romantic-Transcendental Preservationists Ralph Waldo Emerson, Henry David Thoreau, and later John Muir understood American Wilderness as an Eden that ought to be preserved and left untouched. In the early twentieth century, Forester Gifford Pinchot and President Theodore Roosevelt argued against preservationist attitudes toward wilderness, arguing wilderness ought to be wisely used in order to generate prosperity for current and future generations. The thesis illustrates how two different approaches to land use emerged as the United States responded to the impacts of Westward expansion: (1) the romantic-transcendental preservation ethic and (2) the resource conservation ethic. By analyzing preservation and conservation texts and congressional hearings regarding land use in policies in the West, the thesis tracks how wilderness became a symbol of American identity. During the Roosevelt Administration, the social contract between humans and nature was signed into law and ideas on wilderness were transformed into United States Land Use Policy. Gifford Pinchot and Theodore Roosevelt expanded the United States Public Land system and established federal protection of wilderness

A mechanikus keringéstámogatás életet ment - a műszívprogram első három évének tapasztalata a Semmelweis Egyetemen

INTRODUCTION: Since the celebration of the 20th anniversary of the first heart transplantation in Hungary in 2012 the emerging need for modern heart failure management via mechanical circulatory support has evolved. In May 2012 the opening of a new heart failure and transplant unit with 9 beds together with the procurement of necessary devices at Semmelweis University accomplished this need. AIM: The aim of the authors was to report their initial experience obtained in this new cardiac assist device program. METHOD: Since May, 2012, mechanical circulatory support system was applied in 89 cases in 72 patients. Indication for support were end stage heart failure refractory to medical treatment and acute left or right heart failure. RESULTS: Treatment was initiated for acute graft failure after heart transplantation in 27 cases, for end stage heart failure in 24 cases, for acute myocardial infarction in 21 cases, for acute postcardiotomy heart failure in 14 cases, for severe respiratory insufficiency in 2 cases and for drug intoxication in one case. Among the 30 survivor of the whole program 13 patients were successfully transplanted. CONCLUSIONS: The available devices can cover all modalities of current bridge therapy from short term support through medium support to heart transplantation or long term support and destination therapy. These conditions made possible the successful start of a new cardiac assist device program. Orv. Hetil., 2015, 156(13), 521-527

Using multidimensional projection techniques for reaching a high distinguishing ability in biosensing

Recent advances in the control of molecular engineering architectures have allowed unprecedented ability of molecular recognition in biosensing, with a promising impact for clinical diagnosis and environment control. the availability of large amounts of data from electrical, optical, or electrochemical measurements requires, however, sophisticated data treatment in order to optimize sensing performance. in this study, we show how an information visualization system based on projections, referred to as Projection Explorer (PEx), can be used to achieve high performance for biosensors made with nanostructured films containing immobilized antigens. As a proof of concept, various visualizations were obtained with impedance spectroscopy data from an array of sensors whose electrical response could be specific toward a given antibody (analyte) owing to molecular recognition processes. in addition to discussing the distinct methods for projection and normalization of the data, we demonstrate that an excellent distinction can be made between real samples tested positive for Chagas disease and Leishmaniasis, which could not be achieved with conventional statistical methods. Such high performance probably arose from the possibility of treating the data in the whole frequency range. Through a systematic analysis, it was inferred that Sammon's mapping with standardization to normalize the data gives the best results, where distinction could be made of blood serum samples containing 10(-7) mg/mL of the antibody. the method inherent in PEx and the procedures for analyzing the impedance data are entirely generic and can be extended to optimize any type of sensor or biosensor.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)GENOPROTConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Univ São Paulo, Inst Fis Sao Carlos, BR-13560970 São Paulo, BrazilUniv São Paulo, Inst Ciencias Matemat & Computacao, BR-13560970 São Paulo, BrazilUniv São Paulo, Fac Filosofia Ciencias & Letras Ribeirao Preto, BR-14040901 São Paulo, BrazilUniversidade Federal de São Paulo, Dept Biofis, Escola Paulista Med, UNIFESP, BR-04044020 São Paulo, BrazilUniv Fed Rondonia UNIR, Fundacao Oswaldo Cruz Fiocruz Noroeste, BR-76801974 Rondonia, BrazilUniversidade Federal de São Paulo, Dept Biofis, Escola Paulista Med, UNIFESP, BR-04044020 São Paulo, BrazilWeb of Scienc