Download or read book Active Control of Fan Noise written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-02 with total page 54 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report describes the Active Noise Cancellation (ANC) System designed by General Electric and tested in the NASA Lewis Research Center's (LERC) 48 inch Active Noise Control Fan (ANCF). The goal of this study is to assess the feasibility of using wall mounted secondary acoustic sources and sensors within the duct of a high bypass turbofan aircraft engine for global active noise cancellation of fan tones. The GE ANC system is based on a modal control approach. A known acoustic mode propagating in the fan duct is canceled using an array of flush-mounted compact sound sources. The canceling modal signal is generated by a modal controller. Inputs to the controller are signals from a shaft encoder and from a microphone array which senses the residual acoustic mode in the duct. The key results are that the (6,0) was completely eliminated at the 920 Hz design frequency and substantially reduced elsewhere. The total tone power was reduced 6.8 dB (out of a possible 9.8 dB). Farfield reductions of 15 dB (SPL) were obtained. The (4,0) and (4,1) modes were reduced simultaneously yielding a 15 dB PWL decrease. The results indicate that global attenuation of PWL at the target frequency was obtained in the aft quadrant using an ANC actuator and sensor system totally contained within the duct. The quality of the results depended on precise mode generation. High spillover into spurious modes generated by the ANC actuator array caused less than optimum levels of PWL reduction. The variation in spillover is believed to be due to calibration procedure, but must be confirmed in subsequent tests. Pla, Frederic G. and Hu, Ziqiang and Sutliff, Daniel L. Glenn Research Center...

Download or read book NASA Historical Data Book written by Jane Van Nimmen and published by . This book was released on 1988 with total page 560 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1991 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Mohs Micrographic Surgery written by Keyvan Nouri and published by Springer Science & Business Media. This book was released on 2012-03-07 with total page 558 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is written for dermatologists, otolaryngologists, facial plastic surgeons and any physician who want to provide state of the art treatment for skin cancer patients. Considering the high incidence of non-melanoma skin cancers such as Basal Cell Carcinoma and Squamous Cell Carcinoma (accounting for over one million cases per year in the United States) and since Mohs Micrographic Surgery has become the treatment of choice for these skin cancers, the popularity of this technique has been increasing dramatically, worldwide.

Download or read book Hypertension and Cardiovascular Disease written by Emmanuel A. Andreadis and published by Springer. This book was released on 2016-09-20 with total page 392 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides comprehensive analysis into individualized patient care, and applying evidence‐based medicine while integrating basic medical knowledge with applied medicine. The Editor and the contributors not only discuss important issues on hypertension management and its deleterious consequences if it is not well‐controlled, but also highlight the important signaling pathways involved in the pathogenesis of hypertensive heart disease and cardiac hypertrophy.

Download or read book Scalable Shared Memory Multiprocessors written by Michel Dubois and published by Springer Science & Business Media. This book was released on 1992 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mathematics of Computing -- Parallelism.

Download or read book Major Research Topics in Combustion written by M.Y. Hussaini and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 668 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Institute for Computer Applications in Science and Engineer ing (ICASE) and NASA Langley Research Center (LaRC) brought together on October 2-4, 1989 experts in the various areas of com bustion with a view to expose them to some combustion problems of technological interest to LaRC and possibly foster interaction with the academic community in these research areas. The top ics chosen for this purpose were flame structure, flame stability, flame holding/extinction, chemical kinetics, turbulence-kinetics in teraction, transition to detonation, and reacting free shear layers. The lead paper set the stage by discussing the status and issues of supersonic combustion relevant to scramjet engine. Then the ex perts were called upon i) to review the current status of knowledge in the aforementioned ;:I. reas, ii) to focus on how this knowledge can be extended and applied to high-speed combustion, and iii) to suggest future directions of research in these areas. Each topic was then dealt with in a position paper followed by formal discussion papers and a general discussion involving the participants. The position papers discussed the state-of-the-art with an emphasis on key issues that needed to be resolved in the near future. The discussion papers crit ically examined these issues and filled in any lacunae therein. The edited versions of the general discussions in the form of questions from the audience and answers from the speakers are included wher ever possible to give the reader the flavor of the lively interactions that took place.

Download or read book Understanding Mechanical Ventilation written by Ashfaq Hasan and published by Springer Science & Business Media. This book was released on 2010-02-01 with total page 554 pages. Available in PDF, EPUB and Kindle. Book excerpt: Simplify, simplify! Henry David Thoreau For writers of technical books, there can be no better piece of advice. Around the time of writing the first edition – about a decade ago – there were very few monographs on this s- ject: today, there are possibly no less than 20. Based on critical inputs, this edition stands thoroughly revamped. New chapters on ventilator waveforms, airway humidification, and aerosol therapy in the ICU now find a place. Novel software-based modes of ventilation have been included. Ventilator-associated pneumonia has been se- rated into a new chapter. Many new diagrams and algorithms have been added. As in the previous edition, considerable energy has been spent in presenting the material in a reader-friendly, conv- sational style. And as before, the book remains firmly rooted in physiology. My thanks are due to Madhu Reddy, Director of Universities Press – formerly a professional associate and now a friend, P. Sudhir, my tireless Pulmonary Function Lab technician who found the time to type the bits and pieces of this manuscript in between patients, A. Sobha for superbly organizing my time, Grant Weston and Cate Rogers at Springer, London, Balasaraswathi Jayakumar at Spi, India for her tremendous support, and to Dr. C. Eshwar Prasad, who, for his words of advice, I should have thanked years ago. vii viii Preface to the Second Edition Above all, I thank my wife and daughters, for understanding.

Download or read book Effects of Surface Chemistry on Hot Corrosion Life written by and published by . This book was released on 1985 with total page 54 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Steiner Tree Problem written by F.K. Hwang and published by Elsevier. This book was released on 1992-10-20 with total page 353 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Steiner problem asks for a shortest network which spans a given set of points. Minimum spanning networks have been well-studied when all connections are required to be between the given points. The novelty of the Steiner tree problem is that new auxiliary points can be introduced between the original points so that a spanning network of all the points will be shorter than otherwise possible. These new points are called Steiner points - locating them has proved problematic and research has diverged along many different avenues.This volume is devoted to the assimilation of the rich field of intriguing analyses and the consolidation of the fragments. A section has been given to each of the three major areas of interest which have emerged. The first concerns the Euclidean Steiner Problem, historically the original Steiner tree problem proposed by Jarník and Kössler in 1934. The second deals with the Steiner Problem in Networks, which was propounded independently by Hakimi and Levin and has enjoyed the most prolific research amongst the three areas. The Rectilinear Steiner Problem, introduced by Hanan in 1965, is discussed in the third part. Additionally, a forth section has been included, with chapters discussing areas where the body of results is still emerging.The collaboration of three authors with different styles and outlooks affords individual insights within a cohesive whole.

Download or read book Introduction to Mineral Exploration written by Charles Moon and published by Wiley-Blackwell. This book was released on 2006-01-23 with total page 496 pages. Available in PDF, EPUB and Kindle. Book excerpt: This new, up dated edition of Introduction to Mineral Exploration provides a comprehensive overview of all aspects of mineral exploration. Covers not only the nature of mineral exploration but also considers other factors essential to successful exploration, from target evaluation to feasibility studies for extraction and production. Includes six detailed case studies, selected for the range of different problems and considerations they present to the mineral explorationist. Features new chapters on handling mineral exploration data and a new case study on the exploration for diamonds. Essential reading for upper level undergraduates studying ore geology, mineral exploration, mining geology, coal exploration, and industrial minerals, as well as professional geologists. Artwork from the book is available to instructors online at www.blackwellpublishing.com/moon.

Download or read book Active Control of Fan Noise written by National Aeronautics and Space Adm Nasa and published by . This book was released on 2018-11 with total page 50 pages. Available in PDF, EPUB and Kindle. Book excerpt: An extension of a prior study has been completed to examine the potential reduction of aircraft flyover noise by the method of active noise control (ANC). It is assumed that the ANC system will be designed such that it cancels discrete tones radiating from the engine fan inlet or fan exhaust duct, at least to the extent that they no longer protrude above the surrounding broadband noise levels. Thus, without considering the engineering details of the ANC system design, tone levels am arbitrarily removed from the engine component noise spectrum and the flyover noise EPNL levels are compared with and without the presence of tones. The study was conducted for a range of engine cycles, corresponding to fan pressure ratios of 1.3, 1.45, 1.6, and 1.75. This report is an extension of an effort reported previously. The major conclusions drawn from the prior study, which was restricted to fan pressure ratios of 1.45 and 1.75, are that, for a fan pressure ratio of 1.75, ANC of tones gives about the same suppression as acoustic treatment without ANC. For a fan pressure ratio of 1.45, ANC appears to offer less effectiveness from passive treatment. In the present study, the other two fan pressure ratios are included in a more detailed examination of the benefits of the ANC suppression levels. The key results of this extended study are the following observations: (1) The maximum overall benefit obtained from suppression of BPF alone was 2.5 EPNdB at high fan speeds. The suppression benefit increases with increase in fan pressure ratio (FPR), (2) The maximum overall benefit obtained from suppression of the first three harmonics was 3 EPNdB at high speeds. Suppression benefit increases with increase in FPR, (3) At low FPR, only about 1.0 EPNdB maximum reduction was obtained. Suppression is primarily from reduction of BPF at high FPR values and from the combination of tones at low FPR, (4) The benefit from ANC is about the same as the benefit from passive treatment at fan pressure ra...

Download or read book Lasers and Masers written by and published by . This book was released on 1962 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Here Be Dragons written by David Koerner and published by Oxford University Press. This book was released on 2001-11-15 with total page 448 pages. Available in PDF, EPUB and Kindle. Book excerpt: A wealth of new astronomical techniques and space missions may provide this evidence early in the next century."--BOOK JACKET.

Download or read book Hansen Solubility Parameters written by Charles M. Hansen and published by CRC Press. This book was released on 2007-06-15 with total page 546 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hansen solubility parameters (HSPs) are used to predict molecular affinities, solubility, and solubility-related phenomena. Revised and updated throughout, Hansen Solubility Parameters: A User's Handbook, Second Edition features the three Hansen solubility parameters for over 1200 chemicals and correlations for over 400 materials including p

Download or read book Preliminary Determination of Epicenters written by and published by . This book was released on 1970 with total page 494 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Karl Fischer Titration written by Eugen Scholz and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 142 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Karl Fischer titration is used in many different ways following its publication in 1935 and further applications are continually being explored. At the present time we are experiencing another phase of expansion, as shown by the development of new titration equipment and new reagents. KF equipment increasingly incorporates microprocessors which enable the course of a titration to be programmed thus sim plifying the titration. Coulometric titrators allow water determinations in the micro gram-range: the KF titration has become a micro-method. The new pyridine-free re agents make its application significantly more pleasant and open up further possibili ties on account of their accuracy. To make the approach to Karl Fischer titrations easier, we have summarized the present knowledge in this monograph and we have complemented it with our own studies and practical experience. As this book should remain "readable", we have tried to keep the fundamentals to a minimum. Historical developments are only mentioned if they seem to be necessary for understanding the KF reaction. The ap plications are described more fully. Specific details which may interest a particular reader can be found in the original publications cited. The referenced literature is in chronological order as the year of publication may also prove informative. Thus, [6902] for example denotes 69 for 1969 being the year of publication and 02 is a non-recurring progressive number. The referenced litera ture includes summaries which we hope will be of help to find the "right" publica tion easily.