Combustion Of A Polymer Pmma Sphere In Microgravity Classic Reprint

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Combustion Of A Polymer Pmma Sphere In Microgravity

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Author : Jiann C. Yang
language : en
Publisher:
Release Date : 1999

Combustion Of A Polymer Pmma Sphere In Microgravity written by Jiann C. Yang and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1999 with Combustion categories.

The video sequences revealed a number of dynamic events including bubbling and sputtering as well as soot shell formation and break-up during combustion of the spheres at reduced gravity. The ejection of combusting material from the burning spheres represents a fire hazard that must be considered at reduced gravity. The ejection was found to be sensitive to polymer type, but independent of oxygen concentration and pressure. The average value of the ejection frequency was found to be 3 Hz, 5 Hz, and 5 Hz for PMMA, PS, and PP, respectively. The velocities of the ejected material were estimated by tracking the material in two consecutive video frames. For the PP spheres, Va=2.3 (+/-1.2) cm/s (with 60 events observed). The ejected material appeared to decelerate at an average rate of ~40 cm/s2, and traverse an average distance of only 8 mm before burning to completion.

Combustion Of A Polymer Pmma Sphere In Microgravity

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Author : National Aeronautics and Space Adm Nasa
language : en
Publisher: Independently Published
Release Date : 2018-09-19

Combustion Of A Polymer Pmma Sphere In Microgravity written by National Aeronautics and Space Adm Nasa and has been published by Independently Published this book supported file pdf, txt, epub, kindle and other format this book has been release on 2018-09-19 with Science categories.

A series of low gravity, aircraft-based, experiments was conducted to investigate the combustion of supported thermoplastic polymer spheres under varying ambient conditions. The three types of thermoplastic investigated were polymethylmethacrylate (PMMA), polypropylene (PP). and polystyrene (PS). Spheres with diameters ranging from 2 mm to 6.35 mm were tested. The total initial pressure varied from 0.05 MPa to 0. 15 MPa whereas the ambient oxygen concentration varied from 19 % to 30 % (by volume). The ignition system consisted of a pair of retractable energized coils. Two CCD cameras recorded the burning histories of the spheres. The video sequences revealed a number of dynamic events including bubbling and sputtering, as well as soot shell formation and break-up during combustion of the spheres at reduced gravity. The ejection of combusting material from the burning spheres represents a fire hazard that must be considered at reduced gravity. The ejection process was found to be sensitive to polymer type. All average burning rates were measured to increase with initial sphere diameter and oxygen concentration, whereas the initial pressure had little effect. The three thermoplastic types exhibited different burning characteristics. For the same initial conditions, the burning rate of PP was slower than PMMA, whereas the burning rate of PS was comparable to PMMA. The transient diameter of the burning thermoplastic exhibited two distinct periods: an initial period (enduring approximately half of the total burn duration) when the diameter remained approximately constant, and a final period when the square of the diameter linearly decreased with time. A simple homogeneous two-phase model was developed to understand the changing diameter of the burning sphere. Its value is based on a competition between diameter reduction due to mass loss from burning and sputtering, and diameter expansion due to the processes of swelling (density decrease with heating) and bubble growth.

Microgravity Effects On Combustion Of Polymers

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Author : David B. Hirsch
language : en
Publisher:
Release Date : 2000

Microgravity Effects On Combustion Of Polymers written by David B. Hirsch and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2000 with Combustion categories.

NASA Glenn Research Center conducted a cooperative program with the Russian Space Agency Keldysh Research Center, with technical support provided by NASA Johnson Space Center White Sands Test Facility, to investigate polymer combustion in ventilated microgravity in a small combustion tunnel operated on the orbital station Mir. Reported here are ground test results on flammability characteristics of the test materials for verification of the data and conclusions of the space measurements. It was found that very low forced convective flows can sustain polymer combustion in microgravity. Shutoff of the flow, however, is likely to suppress the combustion, particularly if the fire is in the incipient phase and the oxygen concentration is sufficiently low. Relative flammability rankings obtained in ground tests focusing on limiting oxygen index and cone calorimeter heat-release tests would not apply to microgravity environments if the ranking criterion is the minimum forced-flow velocity required for sustained combustion. Convective flows caused by buoyancy in the ground NASA STD 6001 Test 1 far exceeded the minimum forced convective flows required to sustain microgravity combustion. Results indicate that this test provided conservative results for the materials tested in microgravity by sustaining their combustion in less severe oxygen concentration and total pressure conditions than those in which extinguishment occurred in quiescent microgravity environments.

A Gallery Of Combustion And Fire

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Author : Charles E. Baukal, Jr.
language : en
Publisher: Cambridge University Press
Release Date : 2020-09-03

A Gallery Of Combustion And Fire written by Charles E. Baukal, Jr. and has been published by Cambridge University Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2020-09-03 with Law categories.

The first book to present a full-color visual panorama of combustion images along with explanatory and tutorial overviews.

Polymer Chemistry

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Author : Timothy P. Lodge
language : en
Publisher: CRC Press
Release Date : 2020-07-14

Polymer Chemistry written by Timothy P. Lodge and has been published by CRC Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2020-07-14 with Science categories.

A well-rounded and articulate examination of polymer properties at the molecular level, Polymer Chemistry focuses on fundamental principles based on underlying chemical structures, polymer synthesis, characterization, and properties. It emphasizes the logical progression of concepts and provide mathematical tools as needed as well as fully derived problems for advanced calculations. The much-anticipated Third Edition expands and reorganizes material to better develop polymer chemistry concepts and update the remaining chapters. New examples and problems are also featured throughout. This revised edition: Integrates concepts from physics, biology, materials science, chemical engineering, and statistics as needed Contains mathematical tools and step-by-step derivations for example problems Incorporates new theories and experiments using the latest tools and instrumentation and topics that appear prominently in current polymer science journals The number of homework problems has been greatly increased, to over 350 in all The worked examples and figures have been augmented More examples of relevant synthetic chemistry have been introduced into Chapter 2 ("Step-Growth Polymers") More details about atom-transfer radical polymerization and reversible addition/fragmentation chain-transfer polymerization have been added to Chapter 4 ("Controlled Polymerization") Chapter 7 (renamed "Thermodynamics of Polymer Mixtures") now features a separate section on thermodynamics of polymer blends Chapter 8 (still called "Light Scattering by Polymer Solutions") has been supplemented with an extensive introduction to small-angle neutron scattering Polymer Chemistry, Third Edition offers a logical presentation of topics that can be scaled to meet the needs of introductory as well as more advanced courses in chemistry, materials science, polymer science, and chemical engineering.

Properties Of Polymers

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Author : D.W. van Krevelen
language : en
Publisher: Elsevier
Release Date : 2012-12-02

Properties Of Polymers written by D.W. van Krevelen and has been published by Elsevier this book supported file pdf, txt, epub, kindle and other format this book has been release on 2012-12-02 with Technology & Engineering categories.

Properties of Polymers: Their Correlation with Chemical Structure; Their Numerical Estimation and Prediction from Additive Group Contributions summarizes the latest developments regarding polymers, their properties in relation to chemical structure, and methods for estimating and predicting numerical properties from chemical structure. In particular, it examines polymer electrical properties, magnetic properties, and mechanical properties, as well as their crystallization and environmental behavior and failure. The rheological properties of polymer melts and polymer solutions are also considered. Organized into seven parts encompassing 27 chapters, this book begins with an overview of polymer science and engineering, including the typology of polymers and their properties. It then turns to a discussion of thermophysical properties, from transition temperatures to volumetric and calorimetric properties, along with the cohesive aspects and conformation statistics. It also introduces the reader to the behavior of polymers in electromagnetic and mechanical fields of force. The book covers the quantities that influence the transport of heat, momentum, and matter, particularly heat conductivity, viscosity, and diffusivity; properties that control the chemical stability and breakdown of polymers; and polymer properties as an integral concept, with emphasis on processing and product properties. Readers will find tables that give valuable (numerical) data on polymers and include a survey of the group contributions (increments) of almost every additive function considered. This book is a valuable resource for anyone working on practical problems in the field of polymers, including organic chemists, chemical engineers, polymer processers, polymer technologists, and both graduate and PhD students.

Principles Of Polymer Processing

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Author : Zehev Tadmor
language : en
Publisher: John Wiley & Sons
Release Date : 2013-12-02

Principles Of Polymer Processing written by Zehev Tadmor and has been published by John Wiley & Sons this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013-12-02 with Technology & Engineering categories.

Thoroughly revised edition of the classic text on polymer processing The Second Edition brings the classic text on polymer processing thoroughly up to date with the latest fundamental developments in polymer processing, while retaining the critically acclaimed approach of the First Edition. Readers are provided with the complete panorama of polymer processing, starting with fundamental concepts through the latest current industry practices and future directions. All the chapters have been revised and updated, and four new chapters have been added to introduce the latest developments. Readers familiar with the First Edition will discover a host of new material, including: * Blend and alloy microstructuring * Twin screw-based melting and chaotic mixing mechanisms * Reactive processing * Devolatilization--theory, mechanisms, and industrial practice * Compounding--theory and industrial practice * The increasingly important role of computational fluid mechanics * A systematic approach to machine configuration design The Second Edition expands on the unique approach that distinguishes it from comparative texts. Rather than focus on specific processing methods, the authors assert that polymers have a similar experience in any processing machine and that these experiences can be described by a set of elementary processing steps that prepare the polymer for any of the shaping methods. On the other hand, the authors do emphasize the unique features of particular polymer processing methods and machines, including the particular elementary step and shaping mechanisms and geometrical solutions. Replete with problem sets and a solutions manual for instructors, this textbook is recommended for undergraduate and graduate students in chemical engineering and polymer and materials engineering and science. It will also prove invaluable for industry professionals as a fundamental polymer processing analysis and synthesis reference.

Extrusion

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Author : Harold F. Giles Jr
language : en
Publisher: William Andrew
Release Date : 2013-09-21

Extrusion written by Harold F. Giles Jr and has been published by William Andrew this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013-09-21 with Technology & Engineering categories.

The second edition of Extrusion is designed to aid operators, engineers, and managers in extrusion processing in quickly answering practical day-to-day questions. The first part of the book provides the fundamental principles, for operators and engineers, of polymeric materials extrusion processing in single and twin screw extruders. The next section covers advanced topics including troubleshooting, auxiliary equipment, and coextrusion for operators, engineers, and managers. The final part provides applications case studies in key areas for engineers such as compounding, blown film, extrusion blow molding, coating, foam, and reprocessing. This practical guide to extrusion brings together both equipment and materials processing aspects. It covers basic and advanced topics, for reference and training, in thermoplastics processing in the extruder. Detailed reference data are provided on such important operating conditions as temperatures, start-up procedures, shear rates, pressure drops, and safety. A practical guide to the selection, design and optimization of extrusion processes and equipment Designed to improve production efficiency and product quality Focuses on practical fault analysis and troubleshooting techniques

Polymer Process Engineering

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Author : R. Griskey
language : en
Publisher: Springer Science & Business Media
Release Date : 2012-12-06

Polymer Process Engineering written by R. Griskey and has been published by Springer Science & Business Media this book supported file pdf, txt, epub, kindle and other format this book has been release on 2012-12-06 with Technology & Engineering categories.

Polymers are ubiquitous and pervasive in industry, science, and technology. These giant molecules have great significance not only in terms of products such as plastics, films, elastomers, fibers, adhesives, and coatings but also less ob viously though none the less importantly in many leading industries (aerospace, electronics, automotive, biomedical, etc.). Well over half the chemists and chem ical engineers who graduate in the United States will at some time work in the polymer industries. If the professionals working with polymers in the other in dustries are taken into account, the overall number swells to a much greater total. It is obvious that knowledge and understanding of polymers is essential for any engineer or scientist whose professional activities involve them with these macromolecules. Not too long ago, formal education relating to polymers was very limited, indeed, almost nonexistent. Speaking from a personal viewpoint, I can recall my first job after completing my Ph.D. The job with E.I. Du Pont de Nemours dealt with polymers, an area in which I had no university training. There were no courses in polymers offered at my alma mater. My experience, incidentally, was the rule and not the exception.

Polymer Characterisation

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Author : B.J. Hunt
language : en
Publisher: Springer Science & Business Media
Release Date : 2012-12-06

Polymer Characterisation written by B.J. Hunt and has been published by Springer Science & Business Media this book supported file pdf, txt, epub, kindle and other format this book has been release on 2012-12-06 with Science categories.

Polymers continue to play an ever increasing role in the modern world. In fact it is quite inconceivable to most people that we could ever have existed of the increased volume and variety of materials without them. As a result currently available, and the diversity of their application, characterisation has become an essential requirement of industrial and academic laboratories in volved with polymeric materials. On the one hand requirements may come from polymer specialists involved in the design and synthesis of new materials who require a detailed understanding of the relationship between the precise molecular architecture and the properties of the polymer in order to improve its capabilities and range of applications. On the other hand, many analysts who are not polymer specialists are faced with the problems of analysing and testing a wide range of polymeric materials for quality control or material specification purposes. We hope this book will be a useful reference for all scientists and techno or industrial laboratories, logists involved with polymers, whether in academic and irrespective of their scientific discipline. We have attempted to include in one volume all of the most important techniques. Obviously it is not possible to do this in any great depth but we have encouraged the use of specific examples to illustrate the range of possibilities. In addition numerous references are given to more detailed texts on specific subjects, to direct the reader where appropriate. The book is divided into II chapters.