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  • Chemistry  (3,704)
  • Fluid Mechanics and Thermodynamics
  • 2020-2024  (45)
  • 1945-1949  (3,703)
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  • 1
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    IntechOpen | IntechOpen
    Publication Date: 2024-04-05
    Description: Mineralogy includes thirteen chapters that discuss the methodology of specific mineralogical methods, the composition of minerals from different igneous rocks, and the composition of minerals from different sedimentary rocks.It contains detailed mineralogical studies from Africa, Asia, and Europe. Chapters present different scientific mineralogical methods and detailed descriptions of minerals from different magmatic and sedimentary rocks.
    Keywords: Chemistry ; thema EDItEUR::P Mathematics and Science::PN Chemistry::PNV Chemistry of minerals, crystals and gems
    Language: English
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  • 2
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    IntechOpen | IntechOpen
    Publication Date: 2024-04-05
    Description: Benzimidazole is a comprehensive survey of the known and new methods of benzimidazole synthesis, the spectral and theoretical aspects of existing benzimidazole derivatives, and the anticancer properties of a new class of benzimidazole derivatives. This book examines aspects and newer mechanisms of benzimidazoles containing heterocyclic moiety. Chapters report on anticancer properties of benzimidazole derivatives, novel methods of synthesis of benzimidazoles, versatile nature of the benzimidazoles, spectral and theoretical studies of benzimidazole derivatives, and medicinal importance and pharmacological aspects of benzimidazole derivatives.
    Keywords: Chemistry ; thema EDItEUR::P Mathematics and Science::PN Chemistry::PNN Organic chemistry
    Language: English
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  • 3
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    IntechOpen | IntechOpen
    Publication Date: 2024-04-05
    Description: Green Chemistry - New Perspectives is at the frontiers of this continuously evolving interdisciplinary science, and publishes research that attempts to reduce the environmental impact of the chemical enterprise by developing a technology base that is inherently non-toxic to living things and the environment. The book covers all aspects of green chemistry, including chemical synthesis, nano synthesis, eco-friendly processes, biomass, extraction techniques, environmental remediation, and energy, making it a unique reference resource. This will continue to encourage scientists around the world to develop novel synthetic methods or improve the existing ones to circumvent some of the problems and favours all aspects of green chemistry. This book is intended for academia, professionals, scientists, as well as graduate and undergraduate students without any geographical limitations.
    Keywords: Chemistry ; thema EDItEUR::P Mathematics and Science::PN Chemistry::PNN Organic chemistry
    Language: English
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  • 4
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    EDP SCIENCES
    Publication Date: 2024-04-05
    Description: Chemistry
    Keywords: Chemistry ; thema EDItEUR::P Mathematics and Science::PN Chemistry ; thema EDItEUR::P Mathematics and Science::PN Chemistry::PNN Organic chemistry::PNNP Polymer chemistry
    Language: French
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  • 5
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    EDP SCIENCES
    Publication Date: 2024-04-05
    Description: Chemistry
    Keywords: Chemistry ; thema EDItEUR::P Mathematics and Science::PN Chemistry ; thema EDItEUR::P Mathematics and Science::PN Chemistry::PNN Organic chemistry::PNNP Polymer chemistry ; thema EDItEUR::P Mathematics and Science::PN Chemistry ; thema EDItEUR::P Mathematics and Science::PN Chemistry::PNN Organic chemistry::PNNP Polymer chemistry
    Language: French
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  • 6
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    IntechOpen | IntechOpen
    Publication Date: 2024-04-05
    Description: This book consists of several selected chapters on important subjects in modern high-performance liquid chromatography (HPLC) and ultra-performance liquid chromatography (UPLC). The content addresses aspects related to both improvements in the mainstream HPLC/UPLC technology and utilization, as well as developments of exploratory new materials and equipment. The book presents useful details about the presented subjects as well as describes new applications and/or relevant case studies for each subject. It is addressed to a large audience of analytical chemists involved in separation science. Each chapter is authored by scientists with considerable field and academic experience.
    Keywords: Chemistry ; thema EDItEUR::P Mathematics and Science::PN Chemistry::PNF Analytical chemistry
    Language: English
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  • 7
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    EDP SCIENCES
    Publication Date: 2024-04-07
    Description: Chemistry
    Keywords: Chemistry ; thema EDItEUR::P Mathematics and Science::PN Chemistry ; thema EDItEUR::P Mathematics and Science::PN Chemistry::PNN Organic chemistry::PNNP Polymer chemistry
    Language: French
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  • 8
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    IntechOpen | IntechOpen
    Publication Date: 2024-04-05
    Description: Recent Advances in Chemical Kinetics provides a comprehensive overview of several types of chemical reactions. It includes six chapters that discuss solvent catalysis, customized flow reactors, p-conjugation in kinetics, kinetics of autoxidation, molecular chameleon for cations and anions, and internal clocks of atoms.
    Keywords: Chemistry ; thema EDItEUR::P Mathematics and Science::PN Chemistry::PNR Physical chemistry
    Language: English
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  • 9
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    Taylor & Francis | CRC Press
    Publication Date: 2024-03-31
    Description: Hydroxyapatite coatings are of great importance in the biological and biomedical coatings fields, especially in the current era of nanotechnology and bioapplications. With a bonelike structure that promotes osseointegration, hydroxyapatite coating can be applied to otherwise bioinactive implants to make their surface bioactive, thus achieving faster healing and recovery. In addition to applications in orthopedic and dental implants, this coating can also be used in drug delivery. Hydroxyapatite Coatings for Biomedical Applications explores developments in the processing and property characterization and applications of hydroxyapatite to provide timely information for active researchers and newcomers alike. In eight carefully reviewed chapters, hydroxyapatite experts from the United States, Japan, Singapore, and China present the latest on topics ranging from deposition processes to biomedical applications in implants and drug delivery. This book discusses: Magnetron sputtering and electrochemical deposition The modification of hydroxyapatite properties by sol–gel deposition to incorporate other elements found in natural bones, such as zinc, magnesium, and fluorine The use of pure hydroxyapatite in drug delivery applications The growth or self-assembly of hydroxyapatite on shape memory alloy Hydroxyapatite composite coatings—with carbon nanotubes, titanium dioxide (TiO2), and others—on the titanium alloy Offering valuable insights and a wealth of data, including numerous tables and figures, this is a rich source of information for research on hydroxyapatite coatings. Each chapter also covers material that provides an accessible stepping stone for those who are new to the field.
    Keywords: Pre-clinical medicine: basic sciences ; Chemistry ; Materials science ; thema EDItEUR::M Medicine and Nursing::MF Pre-clinical medicine: basic sciences ; thema EDItEUR::P Mathematics and Science::PN Chemistry ; thema EDItEUR::T Technology, Engineering, Agriculture, Industrial processes::TG Mechanical engineering and materials::TGM Materials science
    Language: English
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  • 10
    Publication Date: 2024-04-05
    Description: Chemiebezogene Kompetenzen werden bereits im Sachunterricht der Grundschule entwickelt und sollen im Chemieunterricht der Sekundarstufe I aufgegriffen und weiterentwickelt werden. Ziel dieser Studie war es, die chemiebezogenen Kompetenzen der Schülerinnen und Schüler in der Übergangsphase zwischen Sachunterricht und Chemieunterricht zu analysieren. In einer Ergänzungsstudie wurden zusätzlich sowohl die Auswirkungen der Schulschließungen aufgrund der SARS-CoV-II Pandemie auf die Kompetenzen der Schülerinnen und Schüler als auch der Einfluss einer veränderten Testadministration untersucht. Insgesamt wurden die Kompetenzen von 2262 Lernenden der Jahrgangsstufen 5 bis 9 zu drei Messzeitpunkten analysiert. Die Ergebnisse zeigen, dass die chemiebezogenen Kompetenzen sowohl zum Ende der Grundschulzeit als auch zu Beginn des Chemieunterrichts über alle Kompetenzbereiche hinweg sehr heterogen ausfallen. Dennoch sind sie zu Beginn des Chemieunterrichts in einigen Kompetenzbereichen höher ausgeprägt als zum Ende der Grundschulzeit. Nach den pandemiebedingten Schulschließungen waren die Kompetenzen ähnlich ausgeprägt wie in den gleichen Jahrgangsstufen vor den Schulschließungen. Eine während der Schulschließungen notwendige Bearbeitung der Testhefte von zu Hause aus führte vor allem bei den jüngeren Schülerinnen und Schülern zu besseren Testergebnissen als die Bearbeitung in der Schule. Um die Entwicklung chemiebezogener Kompetenzen in der Übergangsphase zu optimieren, sollte der Erwerb dieser Kompetenzen bereits im Sachunterricht einheitlicher gestaltet werden.
    Keywords: Science ; Chemistry ; Education ; thema EDItEUR::P Mathematics and Science::PN Chemistry ; thema EDItEUR::J Society and Social Sciences::JN Education
    Language: German
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  • 11
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    IntechOpen | IntechOpen
    Publication Date: 2024-04-05
    Description: Redox reactions are involved in biochemistry, energy, corrosion, and much more. In both biology and electrochemistry, the redox reaction is complex and varied. For example, redox shuttles in supercapacitors show aspects of molecular electrochemistry applied to electrode porosity. In pseudocapacitors, the formalism associated with their electrochemical response requires investigation and formalism. Similarly, the simple definition of redox potential opens fundamental questions about its measurement in solutions without supporting salts. This book illustrates the variety of redox reactions in its examination of the importance of redox molecules in the development of new electrical energy storage devices.
    Keywords: Chemistry ; thema EDItEUR::P Mathematics and Science::PN Chemistry::PNR Physical chemistry::PNRH Electrochemistry and magnetochemistry
    Language: English
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  • 12
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    Logos Verlag Berlin | Logos Verlag Berlin
    Publication Date: 2024-04-05
    Description: In 2005, the hybrid model was published by Prof. H.-D. Alber and Prof. P. Zhu as an alternative to the Allen-Cahn model for the description of phase field transformations. With low interfacial energy, it is more efficient, since the resolution of the diffuse interface is numerically broader for the same solution accuracy and allows coarser meshing. The solutions of both models are associated with energy minimisation and in this work the error terms introduced in the earlier publications are discussed and documented using one and two dimensional numerical simulations. In the last part of this book, phase field problems, initially not coupled with material equations, are combined with linear elasticity and, after simple introductory examples, a growing martensitic inclusion is simulated and compared with literature data. In addition to the confirmed numerical advantage, another phenomenon not previously described in the literature is found: with the hybrid model, in contrast to the examples calculated with the Allen-Cahn model, an inclusion driven mainly by curvature energy does not disappear completely. The opposite problem prevents inclusions from growing from very small initial configurations, but this fact can be remedied by a very finely chosen diffuse interface width and by analysing and adjusting the terms that generate the modelling errors. The last example shows that the hybrid model can be used with numerical advantages despite the above mentioned peculiarities.
    Keywords: Science ; Chemistry ; Mathematics ; Science ; Physics ; thema EDItEUR::P Mathematics and Science::PN Chemistry ; thema EDItEUR::P Mathematics and Science::PB Mathematics ; thema EDItEUR::P Mathematics and Science::PH Physics
    Language: English
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  • 13
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    IntechOpen | IntechOpen
    Publication Date: 2024-04-05
    Description: We are living in a critical time, both for humanity and the planet, which has led us to look for more sustainable formulas to interact with the environment. One of the important changes in the design and operation of chemical processes is the search for environmentally friendly technologies. Supercritical carbon dioxide has been revealed as a promising environmentally friendly solvent that is energy efficient, selective and capable of reducing waste, making it a promising alternative to conventional organic solvents. However, reliable and versatile mathematical models of phase equilibrium thermodynamics are needed for the use of supercritical carbon dioxide in process design and viability studies. This book reviews experimental procedures for obtaining high-pressure phase equilibria data and describes the phase diagrams of binary mixtures and some thermodynamic models capable of determining the conditions of phase equilibria at high pressures. These concepts are applied to the components of the transesterification reaction of rac-2-pentanol with a vinyl ester, which is important in the pharmaceutical industry because (S)-2-pentanol can be obtained as a reaction product. This product is a key intermediate in the synthesis of drugs against Alzheimer’s disease.
    Keywords: Chemistry ; thema EDItEUR::P Mathematics and Science::PN Chemistry::PNR Physical chemistry
    Language: English
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  • 14
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    MDPI - Multidisciplinary Digital Publishing Institute
    Publication Date: 2024-04-05
    Description: Nanofibers, particularly those of a carbonaceous content, have received increased interest in the past two decades due to their outstanding physico-chemical characteristics and their possibility to form and contribute towards a plethora of potentially advantageous materials for consumer, industrial and medical applications. Despite this, and together with the numerous research studies and published articles that have sought to investigate these aspects, the potential impact of CNTs is still not understood. Whether or not nanofibers may be able to provide a sophisticated alternative to conventional materials is still debatable, whilst their effects upon both environmental and human health are highly equivocal. How nanofibers are conceived can determine how they may interact with different environments, such as the human body. Understanding each key step of the synthesis and production of nanofibers to their use within potential applications is therefore essential in gaining an insight into how they may be perceived by any biological system and environment. Thus, obtaining such information will enable all scientific communities to begin to realize the potential advantages posed by nanofibers. The aim of this Special Issue therefore, was to provide a collective overview of nanofibers; ‘from synthesis to application’. The Issue particularly focuses upon carbon-based nanofibers, but also highlights alternative nanofiber types. Emphasis is given holistically, with articles discussing the production routes of nanofibers, their plight during their life-cycle (origin to applied form and effects over time), as well as how nanofibers could either incite conflict, or provide aid to human and environmental health.
    Keywords: QD1-999 ; Toxicology ; Chemistry ; Biology ; Material Science ; Nanofibers ; Nanotechnology ; thema EDItEUR::P Mathematics and Science::PN Chemistry
    Language: English
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  • 15
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    IntechOpen | IntechOpen
    Publication Date: 2024-04-05
    Description: In recent decades, artificial porous structures have attracted increasing enthusiasm from researchers inspired by the fascinating molecular pores in nature and their unique biological functions. Although substantial achievements in porous materials have been realized, the construction of topologically designed pores is still challenging. Recently, the emergence of covalent organic frameworks (COFs), which are constructed based on organic and polymer chemistry, has made it possible to design artificial pores with controlled pore size, topology and interface properties. COFs are crystalline porous materials constructed by the precise reticulation of organic building blocks via dynamic covalent bonds. Distinct from non-covalent interactions which tend to produce isostructures, covalent bonds enable accurate pore design owing to their predetermined reaction pathways. In addition, the appropriate polycondensation of organic building units enables the formation of extended two-dimensional (2D) and three-dimensional (3D) polymer architectures with periodically ordered skeletons and well-defined pores. With their large surface area, tailorable structures, and tunable chemistry, COFs are regarded as potentially superior candidates for various applications including catalysis, energy storage and conversion, mass transport and biotechnology. This book examines the historic achievement of COFs, providing clear and comprehensive guidance for researchers on their structural design, synthetic protocols and functional exploration.
    Keywords: Chemistry ; thema EDItEUR::P Mathematics and Science::PN Chemistry::PNN Organic chemistry
    Language: English
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  • 16
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    IntechOpen | IntechOpen
    Publication Date: 2024-04-05
    Description: Fluoride covers a continuum of topics that are frequently studied in the broad area of fluoride (F) research. It provides an overview of the primary sources of environmental fluoride in typical high-fluoride environments and demonstrates the transitions and transformations that emerge and culminate in hydro-geochemical interactions that result in fluoride-fouling of large portions of the world’s water and agricultural resources. This way, the book pinpoints the connection between F enrichment of water sources and the prevalence of endemic fluorosis in certain areas of the world. In order to contribute to a better understanding of the global fluoride problem, new fluoride detection and quantification technologies are proposed with an in-depth analysis of emerging trends in the use of portable user-friendly devices in point-of-use measurements of water fluoride. This has been presented against the backdrop of a robust overview of traditional fluoride quantification methodologies that are still in wide application among the scientific communities. In addressing fluoride toxicities, which are not limited to dental and skeletal dilapidations, the authors have explored the role of natural antioxidants in ameliorating physiological fluoride-induced noxious effects in mammalian systems. Nonetheless, since community dependence on high-fluoride water due to a lack of alternative clean water sources remains to be the principal pathway of human fluoride over-exposure, a review chapter on F mitigation techniques applied all over the world is incorporated aiming at providing a succinct overview of water defluoridation techniques and strategies being used to combat the impacts of human F overexposure around the globe. Since every cloud has a silvery lining, the possibility of using ammonium fluorides as a novel reagent in mineral processing has been considered convenient industrial fluorinating agents, which present the possibility of complete regeneration that is not afforded by the reagents presently used in decomposing silicon component of the ores.
    Keywords: Chemistry ; thema EDItEUR::P Mathematics and Science::PN Chemistry::PNK Inorganic chemistry
    Language: English
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  • 17
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    IntechOpen | IntechOpen
    Publication Date: 2024-04-05
    Description: This book discusses the chemistry and applications of pyridine derivatives. The library of pyridine derivatives is growing steadily with numerous synthetic analogues already described and the identification of new, naturally occurring pyridine-based compounds. The book includes ten chapters organized into two parts. The first part focuses on the numerous types of reactions that arise from pyridine derivatives. The second part examines the pharmaceutical applications of pyridine derivatives as well as their usefulness as sensors for metal cations and extracting agents for platinum group metals.
    Keywords: Chemistry ; thema EDItEUR::P Mathematics and Science::PN Chemistry::PNN Organic chemistry
    Language: English
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  • 18
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    IntechOpen | IntechOpen
    Publication Date: 2024-04-05
    Description: The book discusses multiple issues associated with modern dosimetry in physics and treatment planning and how investigators from diverse world centers and institutions approach problem-solving in these important areas. It examines topics including pretreatment validation and factors affecting reference dosimetry. It also addresses unique issues affecting pediatric populations as well as the modern role of thermoluminescence validation. Several chapters discuss intensity modulation, including defining modern problems associated with both treatment planning and the definition of tumor and normal tissue contours. Furthermore, the book examines the role of imaging as both a vehicle to define tumor targets and normal tissue as well as a tool for dose validation.
    Keywords: Chemistry ; thema EDItEUR::P Mathematics and Science::PN Chemistry::PNR Physical chemistry::PNRL Nuclear chemistry, photochemistry and radiation
    Language: English
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  • 19
    Publication Date: 2024-04-05
    Description: Das selbstgesteuerte Experimentieren ist laut den nationalen Bildungsstandards sowie den Lehrplänen im Fach Chemie ein wichtiger Bestandteil der naturwissenschaftlichen Schulbildung. Offene Experimentierformen sind jedoch wenig etabliert. Um das selbstgesteuerte Experimentieren in die Unterrichtspraxis zu implementieren, wurde im Rahmen dieses Forschungsprojekts eine eintägige Lehrkräftefortbildung zur Konzeption von selbstgesteuerten Experimenten im Chemieunterricht durchgeführt. Dazu wurde ein literaturbasiertes Strukturierungskonzept entwickelt, mit dem die Lehrkräfte kochbuchartige Schulversuche zu selbstgesteuerten und kompetenzorientierten Experimenten mit beliebigen Öffnungsgraden modifizieren können. Begleitend zur Fortbildung wurde im Prä-Post-Follow-Up-Design das fachdidaktische Wissen der Teilnehmenden hinsichtlich der Planung von selbstgesteuerten Experimenten empirisch überprüft. Zur Erfassung dieses Konstrukts wurde ein neues Messinstrument literaturbasiert entwickelt und die Güte des Messinstruments evaluiert. Die Auswertungen zeigen, dass die Fortbildung hinsichtlich des fachdidaktischen Wissens der Lehrkräfte kurz- sowie langfristig lernförderlich ist und die Fortbildung von den Teilnehmenden positiv bewertet wird. Die Reliabilitätsanalyse sowie die Validierungsstudie zeigen, dass der Test sowohl reliabel als auch valide ist. In Folgestudien könnte die langfristige Verhaltensänderung der Lehrkräfte bezüglich der Implementierung des selbstgesteuerten Experimentierens in den Unterricht untersucht werden.
    Keywords: Science ; Chemistry ; Science ; Education ; thema EDItEUR::P Mathematics and Science::PN Chemistry ; thema EDItEUR::P Mathematics and Science::PD Science: general issues ; thema EDItEUR::J Society and Social Sciences::JN Education
    Language: German
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  • 20
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    IntechOpen | IntechOpen
    Publication Date: 2024-04-05
    Description: The book comprises 14 chapters covering all the issues related to water desalination. These chapters emphasize the relationship between problems encountered with the use of feed water, the processes developed to address them, the operation of the required plants and solutions actually implemented. This compendium will assist designers, engineers and investigators to select the process and plant configuration that are most appropriate for the particular feed water to be used, for the geographic region considered, as well as for the characteristics required of the treated water produced. This survey offers a comprehensive, hierarchical and logical assessment of the entire desalination industry. It starts with the worldwide scarcity of water and energy, continues with the thermal - and membrane-based processes and, finally, presents the design and operation of large and small desalination plants. As such, it covers all the scientific, technological and economical aspects of this critical industry, not disregarding its environmental and social points of view. One of InTech's books has received widespread praise across a number of key publications. Desalination, Trends and Technologies (Ed. Schorr, M. 2011) has been reviewed in Corrosion Engineering, Science & Technology – the official magazine for the Institute of Materials, Minerals & Mining, and Taylor & Francis's Desalination Publications. Praised for its “multi-faceted content [which] contributes to enrich it,” and described as “an essential companion...[that] enables the reader to gain a deeper understanding of the desalination industry,” this book is testament to the quality improvements we have been striving towards over the last twelve months.
    Keywords: Chemistry ; thema EDItEUR::P Mathematics and Science::PN Chemistry::PNF Analytical chemistry
    Language: English
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  • 21
    Publication Date: 2024-04-05
    Description: The Global Methane Initiative (GMI) is a voluntary international partnership that promotes methane recovery and reuse activities in developing and transition economies. The U.S. Department of State requested an evaluation of the activities and outcomes supported in whole or in part by its contributions to GMI to gauge its value added to the program.
    Keywords: Physics ; Environmental Science ; Chemistry ; thema EDItEUR::P Mathematics and Science::PN Chemistry ; thema EDItEUR::T Technology, Engineering, Agriculture, Industrial processes::TQ Environmental science, engineering and technology ; thema EDItEUR::R Earth Sciences, Geography, Environment, Planning::RB Earth sciences::RBP Meteorology and climatology
    Language: English
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  • 22
    Publication Date: 2024-04-04
    Description: This volume, occasioned by the centenary of the Fritz Haber Institute, formerly the Institute for Physical Chemistry and Electrochemistry, covers the institute's scientific and institutional history from its founding until the present. The institute was among the earliest established by the Kaiser Wilhelm Society, and its inauguration was one of the first steps in the development of Berlin-Dahlem into a center for scientific research. Its establishment was made possible by an endowment from Leopold Koppel, granted on the condition that Fritz Haber, well-known for his discovery of a method to synthesize ammonia from its elements, be made its director. The history of the institute has largely paralleled that of 20th-century Germany. It undertook controversial weapons research during World War I, followed by a "Golden Era" during the 1920s, in spite of financial hardships.
    Keywords: Chemistry ; Chemistry ; Fritz Haber Institute ; thema EDItEUR::P Mathematics and Science::PD Science: general issues::PDX History of science
    Language: English
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  • 23
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    IntechOpen | IntechOpen
    Publication Date: 2024-04-05
    Description: Progress in agricultural, biomedical and industrial applications' is a compilation of recent advances and developments in gas chromatography and its applications. The chapters cover various aspects of applications ranging from basic biological, biomedical applications to industrial applications. Book chapters analyze new developments in chromatographic columns, microextraction techniques, derivatisation techniques and pyrolysis techniques. The book also includes several aspects of basic chromatography techniques and is suitable for both young and advanced chromatographers. It includes some new developments in chromatography such as multidimensional chromatography, inverse chromatography and some discussions on two-dimensional chromatography. The topics covered include analysis of volatiles, toxicants, indoor air, petroleum hydrocarbons, organometallic compounds and natural products. The chapters were written by experts from various fields and clearly assisted by simple diagrams and tables. This book is highly recommended for chemists as well as non-chemists working in gas chromatography.
    Keywords: Chemistry ; thema EDItEUR::P Mathematics and Science::PN Chemistry::PNF Analytical chemistry
    Language: English
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  • 24
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    IntechOpen | IntechOpen
    Publication Date: 2024-04-05
    Description: This book discusses electrocatalysis and electrocatalysts for energy, water electrolysis, water treatment, CO2 conversion, and green chemistry. It reviews various electrocatalysts and their properties and electrochemical performances. The first section of the book covers topics in direct alcohol fuel cells including Pt-based electrocatalysts as non-carbon electrode support materials and the development of electrocatalysts for direct methanol fuel cells. The second section of the book covers various topics in electrocatalysis and electrocatalysts for a cleaner environment, including electrocatalysts for the conversion of CO2 to valuable products and SYNGAS, electrocatalysts for water electrolysis, and much more.
    Keywords: Chemistry ; thema EDItEUR::P Mathematics and Science::PN Chemistry::PNR Physical chemistry::PNRH Electrochemistry and magnetochemistry
    Language: English
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  • 25
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    transcript Verlag | transcript Verlag
    Publication Date: 2024-04-04
    Description: Die Chemie büßt zugunsten physikalischer und lebenswissenschaftlicher Konzeptionen zunehmend an Deutungsmacht über die molekulare Welt ein. Sandra Lang untersucht, inwiefern die Ausdifferenzierung der chemischen Wissenschaften mit sich ebenfalls ausdifferenzierenden Zugriffen auf das Molekulare zusammenhängt. Anhand der vier exemplarischen Grenzfelder Materialwissenschaften, Biomedizin, Pharmazie und Quantenchemie und deren Narrative zur molekularen Eigenschaft der Chiralität veranschaulicht sie die transformative Phase der Chemie angesichts sich wandelnder Innovationsdispositive.
    Keywords: Chemie ; Chiralität ; Molekülkonzept ; Naturwissenschaften ; Grenzarbeit ; Interdisziplinarität ; Hybridität ; Wissenschaft ; Technik ; Wissenschaftssoziologie ; Techniksoziologie ; Wissenssoziologie ; Wissenschaftsgeschichte ; Soziologie ; Chemistry ; Chirality ; Molecule Concept ; Natural Sciences ; Border Work ; Interdisciplinarity ; Hybridity ; Science ; Technology ; Sociology of Science ; Sociology of Technology ; Sociology of Knowledge ; History of Science ; Sociology ; thema EDItEUR::P Mathematics and Science::PD Science: general issues::PDR Impact of science and technology on society ; thema EDItEUR::J Society and Social Sciences::JH Sociology and anthropology::JHB Sociology
    Language: German
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  • 26
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    IntechOpen | IntechOpen
    Publication Date: 2024-04-05
    Description: Surfactants are ubiquitous and have applications in diverse areas, including food, cosmetics, detergents, lubricants, enhanced oil recovery (EOR), and targeted drug delivery systems. Their wide diversity of applications owes to their unique structure, namely, a hydrophilic and a hydrophobic group present in the same molecule. Although most surfactants used industrially are synthetic, there is a growing need for natural surfactants, as the latter is obtainable from renewable sources and are less toxic and highly biodegradable in contrast to their synthetic counterparts. This book is a compilation of interesting articles by various experts that cover various applications of both synthetic and natural surfactants.
    Keywords: Chemistry ; thema EDItEUR::P Mathematics and Science::PN Chemistry::PNR Physical chemistry::PNRC Colloid chemistry
    Language: English
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  • 27
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    IntechOpen | IntechOpen
    Publication Date: 2024-04-05
    Description: The chemical sensor plays an essential role in the fields of environmental conservation and monitoring, disaster and disease prevention, and industrial analysis. A typical chemical sensor is a device that transforms chemical information in a selective and reversible way, ranging from the concentration of a specific sample component to total composition analysis, into an analytically useful signal. Much research work has been performed to achieve a chemical sensor with such excellent qualities as quick response, low cost, small size, superior sensitivity, good reversibility and selectivity, and excellent detection limit. This book introduces the latest advances on chemical sensors. It consists of 15 chapters composed by the researchers active in the field of chemical sensors, and is divided into 5 sections according to the classification following the principles of signal transducer. This collection of up-to-date information and the latest research progress on chemical sensor will provide valuable references and learning materials for all those working in the field of chemical sensors.
    Keywords: Chemistry ; thema EDItEUR::P Mathematics and Science::PN Chemistry::PNF Analytical chemistry
    Language: English
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    EDP SCIENCES
    Publication Date: 2024-04-05
    Description: Chemistry
    Keywords: Chemistry ; thema EDItEUR::P Mathematics and Science::PN Chemistry ; thema EDItEUR::P Mathematics and Science::PN Chemistry::PNN Organic chemistry::PNNP Polymer chemistry ; thema EDItEUR::P Mathematics and Science::PN Chemistry ; thema EDItEUR::P Mathematics and Science::PN Chemistry::PNN Organic chemistry::PNNP Polymer chemistry
    Language: French
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  • 29
    Publication Date: 2024-04-05
    Description: Chemistry
    Keywords: Chemistry ; thema EDItEUR::P Mathematics and Science::PN Chemistry ; thema EDItEUR::P Mathematics and Science::PN Chemistry::PNN Organic chemistry::PNNP Polymer chemistry ; thema EDItEUR::P Mathematics and Science::PN Chemistry ; thema EDItEUR::P Mathematics and Science::PN Chemistry::PNN Organic chemistry::PNNP Polymer chemistry
    Language: French
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  • 30
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    De Gruyter | De Gruyter
    Publication Date: 2024-04-11
    Description: Presents technologies and key concepts to produce suitable smart materials and intelligent structures for sensing, information and communication technology, biomedical applications (drug delivery, hyperthermia therapy), self-healing, flexible memories and construction technologies. Novel developments of environmental friendly, cost-effective and scalable production processes are discussed by experts in the field.
    Keywords: Science ; Chemistry ; Industrial & Technical ; Technology & Engineering ; Textiles & Polymers ; thema EDItEUR::T Technology, Engineering, Agriculture, Industrial processes::TD Industrial chemistry and manufacturing technologies::TDC Industrial chemistry and chemical engineering ; thema EDItEUR::T Technology, Engineering, Agriculture, Industrial processes::TG Mechanical engineering and materials::TGM Materials science
    Language: English
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  • 31
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    IntechOpen | IntechOpen
    Publication Date: 2024-04-05
    Description: Distillation is an important separation technique that has been used for many centuries to exploit the volatility differences between components in a mixture. The distillation process has many variations and applications. This book includes two sections on desalination and reactive distillation. It discusses desalination in the processes of solar and membrane distillation, with a focus on the reduction of energy costs to obtain potable water. It also discusses reactive distillation, which can be used in some cases to reduce the power duty in the separation process by using the reaction heat directly in the separation. The book includes cases of mathematical modeling, simulation, and optimization of the distillation process.
    Keywords: Chemistry ; thema EDItEUR::P Mathematics and Science::PN Chemistry::PNF Analytical chemistry
    Language: English
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  • 32
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    Logos Verlag Berlin | Logos Verlag Berlin
    Publication Date: 2024-04-05
    Description: Konsumgüter werden beispielsweise mit Slogans wie "Gut in Bio. Schlecht in Chemie." beworben. Dabei wird intendiert, sich gezielt von "Chemie" abzugrenzen und sich das positive Bild von "Natur" zu Nutze zu machen. Dies prägt die öffentliche Meinung und trägt zu einer antagonistisch-wertenden Sicht von "Chemie" und "Natur" bei. Dass Chemie als Naturwissenschaft der Beschreibung der Natur dient, um deren Stoffe und Stoffumwandlungen zu erklären, ist dem Laien selten bewusst. Chemie findet überall statt, insbesondere in der Natur! Genau an diesem Punkt setzt das Unterrichtskonzept "Chemie Pur - Unterrichten in der Naturglqq an. Ziel ist es, im Freiland, mit direkt vor Ort gewonnenen Naturstoffen, Umweltprozesse experimentell zu erarbeiten. Die projektbegleitende Evaluationsstudie stellte sich der Forschungsfrage, wie sich das Unterrichtskonzept auf das Fach- und Sachinteresse, auf die Naturverbundenheit sowie auf die Einstellung zu Chemie und Natur von Schülerinnen und Schülern der Sekundarstufe II auswirkt. Die Auswertung der Fragebogenergebnisse mit latenten Veränderungsmodellen haben gezeigt, dass die Intervention im Freiland das inhaltsbezogene Sachinteresse steigert und die Einstellung zu Chemie und Natur positiv beeinflusst sowie ein erhöhten Fachwissenszuwachs ermöglicht. Die gewonnenen Erkenntnisse können die Grundlage für die Entwicklung und Evaluation von good-practice-Ansätzen naturwissenschaftlicher Lernsituationen bilden. Das Unterrichtskonzept Chemie Pur leistet zudem einen Beitrag im Bereich Outdoor Education, um den Antagonismus von Chemie und Natur zu verringern.
    Keywords: Science ; Chemistry ; Science ; Education ; thema EDItEUR::P Mathematics and Science::PN Chemistry ; thema EDItEUR::P Mathematics and Science::PD Science: general issues ; thema EDItEUR::J Society and Social Sciences::JN Education
    Language: German
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  • 33
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    De Gruyter | De Gruyter
    Publication Date: 2024-04-05
    Description: Comprise definition of 1500 terms. Innovation from A to Z presents a glossary, including: Terms, older terms whose meanings have changed, acronyms, synonyms, famous names, selected abbreviations, and cross-references. A highly interdisciplinary approach incorporating strategy and entrepreneurship with technology and engineering sciences, economics, marketing, organizational behavior and theory. Ideal for engineers, managers, sales people and economists. Innovation Technology from A to Z Glossary of terms, including acronyms, synonyms, abbreviations, cross-references 1500 terms supplemented by figures and tables that clearly demonstrate the state-of-the-art in Innovation Technology
    Keywords: Science ; Chemistry ; Technology & Engineering ; Agriculture ; thema EDItEUR::P Mathematics and Science::PN Chemistry ; thema EDItEUR::T Technology, Engineering, Agriculture, Industrial processes::TV Agriculture and farming
    Language: English
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  • 34
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    EDP SCIENCES
    Publication Date: 2024-04-08
    Description: Chemistry
    Keywords: Chemistry ; thema EDItEUR::P Mathematics and Science::PN Chemistry::PNN Organic chemistry::PNNP Polymer chemistry
    Language: French
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  • 35
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    IntechOpen | IntechOpen
    Publication Date: 2024-04-05
    Description: Cyclodextrins (CDs) have attracted great interest from the research community as well as industries in an array of sectors because of their unique structural features. This book provides a comprehensive overview of CDs, beginning with their historical background. Chapters address such topics as the structure and physiochemical properties of CDs, advancements in the field, and potential applications of these materials in fields such as drug delivery and sensing. This book reveals new frontiers in the CD world and is a useful resource for organic, analytical, and supramolecular chemists as well as scientists engaged in biological and material sciences.
    Keywords: Chemistry ; thema EDItEUR::P Mathematics and Science::PN Chemistry::PNN Organic chemistry::PNNP Polymer chemistry
    Language: English
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  • 36
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    IntechOpen | IntechOpen
    Publication Date: 2024-04-05
    Description: The book presents a comprehensive overview of sorption, which is a multi-parametric separation process. It is extensively used in the removal of various pollutants from the tertiary stage of wastewater treatment, from leachates, etc. It discusses fundamental points of the technique as well as kinetic theories and isotherms. It also examines the synthesis and characterizations of all studied adsorbent materials to find their paths of sorption. Finally, it highlights the importance of having a cost-estimation plan for the synthesis of sorbent materials as well as predictions for their reusability.
    Keywords: Chemistry ; thema EDItEUR::P Mathematics and Science::PN Chemistry::PNR Physical chemistry::PNRX Surface chemistry and adsorption
    Language: English
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  • 37
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    EDP SCIENCES
    Publication Date: 2024-04-05
    Description: Chemistry;Materials science
    Keywords: Chemistry ; Materials science ; thema EDItEUR::P Mathematics and Science::PN Chemistry ; thema EDItEUR::P Mathematics and Science::PN Chemistry::PNN Organic chemistry::PNNP Polymer chemistry
    Language: French
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  • 38
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    The MIT Press | The MIT Press
    Publication Date: 2024-03-27
    Description: The original 1818 text of Mary Shelley's classic novel, with annotations and essays highlighting its scientific, ethical, and cautionary aspects. Mary Shelley's Frankenstein has endured in the popular imagination for two hundred years. Begun as a ghost story by an intellectually and socially precocious eighteen-year-old author during a cold and rainy summer on the shores of Lake Geneva, the dramatic tale of Victor Frankenstein and his stitched-together creature can be read as the ultimate parable of scientific hubris. Victor, “the modern Prometheus,” tried to do what he perhaps should have left to Nature: create life. Although the novel is most often discussed in literary-historical terms—as a seminal example of romanticism or as a groundbreaking early work of science fiction—Mary Shelley was keenly aware of contemporary scientific developments and incorporated them into her story. In our era of synthetic biology, artificial intelligence, robotics, and climate engineering, this edition of Frankenstein will resonate forcefully for readers with a background or interest in science and engineering, and anyone intrigued by the fundamental questions of creativity and responsibility. This edition of Frankenstein pairs the original 1818 version of the manuscript—meticulously line-edited and amended by Charles E. Robinson, one of the world's preeminent authorities on the text—with annotations and essays by leading scholars exploring the social and ethical aspects of scientific creativity raised by this remarkable story. The result is a unique and accessible edition of one of the most thought-provoking and influential novels ever written. Essays by Elizabeth Bear, Cory Doctorow, Heather E. Douglas, Josephine Johnston, Kate MacCord, Jane Maienschein, Anne K. Mellor, Alfred Nordmann
    Keywords: science fiction ; gothic ; horror ; European ; British ; literature ; fiction ; cautionary tale ; STEM ; science ; bioethics ; classic ; bicentennial ; Josephine Johnston ; Cory Doctorow ; Jane Maienschein ; Kate MacCord ; Alfred Nordmann ; Elizabeth Bear ; Anne K. Mellor ; Heather E. Douglas ; Frankenstein ; Creature ; Monster ; Mary Shelley ; Makers ; women in science ; science and anti-science ; values in science ; responsible innovation ; Industrial Revolution ; Mary Wollstonecraft ; William Godwin ; Percy Bysshe Shelley ; Galvanism ; Mount Tambora ; Myths ; Two Cultures ; epistolary novel ; Victor Frankenstein ; Geneva ; Prometheus ; Arctic ; Lord Byron ; John Polidori ; ghost stories ; Revisions ; Electricity ; Lightning ; Vitalism ; Chemistry ; Extinction ; Magnetism ; Moral responsibility ; Legal responsibility ; Social responsibility ; Consequences ; Obligations ; Ethics ; Maker Culture ; DIY ; Technology Adjacent Possible ; Facebook ; Surveillance ; Aristotle ; Fetal development ; Epigenesis ; Embryo ; Person ; Technoscience ; Alchemy ; uncanny valley ; animation ; complexity ; Morality ; Monstrosity ; Christianity ; Otherness ; Gender ; Nature ; Domestic Affections ; Women ; Sexuality ; Technical Sweetness ; Los Alamos ; Trinity Test ; Scientific Responsibility ; Nuclear Weapons ; adjacent possible ; synthetic biology ; robotics ; thema EDItEUR::F Fiction and Related items::FB Fiction: general and literary::FBC Classic fiction: general and literary ; thema EDItEUR::F Fiction and Related items::FL Science fiction::FLC Classic science fiction
    Language: English
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  • 39
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    Coimbra University Press
    Publication Date: 2022-01-31
    Description: This work brings together various contributions from experts in very diverse areas of knowledge, to discuss the theme ‘Light’ from various points of view. The subjects gathered in this work come from the areas of Physics, Philosophy, Transcendence, Chemistry, Optics, Literature, History of Sciences, History, Geography, International Relations, Biology, Psychology, Art, Cinema and Photography, Medicine and Museology. The texts partially reflect the contents presented at the interdisciplinary colloquium ‘Visões da Luz’ held in October 2015, on the occasion of the International Year of Light 2015, under the aegis of III-UC and open to academia and society, to teachers of the Basic and Secondary Education.
    Keywords: Geography ; Chemistry ; Literature ; Geology ; Light ; Optics ; Biology ; History ; Physics
    Language: Portuguese
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  • 40
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    IntechOpen | IntechOpen
    Publication Date: 2024-04-05
    Description: Carotenoids are natural and versatile secondary metabolites, most of them showing colours that vary from yellow to red. They are widespread among living beings where they are involved in many biological roles reporting beneficial actions. To date, more than 750 carotenoids have been described in nature. Humans cannot synthesize carotenoids de novo, thus they are mainly obtained through diet. In fact, carotenoids are consistently found in tissues or biological fluids where they play a beneficial decreasing the risk of developing some diseases.During the last half-century, significant advances in carotenoids research have been made. This book highlights new perspectives and applications of carotenoids including characterization and isolation of new compounds (including rare carotenoids), their production at a mid-large scale (involving new innovative approaches), and uses of carotenoids in different biotechnological fields like food science, biomedicine, and cosmetics.
    Keywords: Chemistry ; thema EDItEUR::P Mathematics and Science::PN Chemistry::PNN Organic chemistry
    Language: English
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  • 41
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    EDP SCIENCES
    Publication Date: 2024-04-05
    Description: Chemistry
    Keywords: Chemistry ; thema EDItEUR::P Mathematics and Science::PN Chemistry ; thema EDItEUR::P Mathematics and Science::PN Chemistry::PNN Organic chemistry::PNNP Polymer chemistry
    Language: French
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  • 42
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    IntechOpen | IntechOpen
    Publication Date: 2024-04-05
    Description: Infrared Spectroscopy - Perspectives and Applications is a compendium of contributions from experts in the field of infrared (IR) spectroscopy. This assembly of investigations and reviews provides a comprehensive overview of the fundamentals as well as the groundbreaking applications in the field. Chapters discuss IR spectroscopy applications in the food and biomedicine sectors and for measuring transport through polymer membranes, characterizing lignocellulosic biomasses, detecting adulterants, and characterizing enamel surface advancements. This book is an invaluable resource and reference for students, researchers, and other interested readers.
    Keywords: Chemistry ; thema EDItEUR::P Mathematics and Science::PN Chemistry::PNF Analytical chemistry::PNFS Spectrum analysis, spectrochemistry, mass spectrometry
    Language: English
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  • 43
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    Logos Verlag Berlin | Logos Verlag Berlin
    Publication Date: 2024-04-05
    Description: When auralizing moving sound sources in Virtual Reality (VR) environments, the two main input parameters are the location and radiated signal of the source. An array measurement-based model is developed to characterize moving sound sources regarding the two parameters in this thesis. This model utilizes beamforming, i.e. delay and sum beamforming (DSB) and compressive beamforming (CB) to obtain the locations and signals of moving sound sources. A spiral and a pseudorandom microphone array are designed for DSB and CB, respectively, to yield good localization ability and meet the requirement of CB. The de-Dopplerization technique is incorporated in the time-domain DSB to address moving source problems. Time-domain transfer functions (TDTFs) are calculated in terms of the spatial locations within the steering window of the moving source. TDTFs then form the sensing matrix of CB, thus allowing CB to solve moving source problem. DSB and CB are further extended to localize moving sound sources, and the reconstructed signals from the beamforming outputs are investigated to obtain the source signals. Moreover, localization and signal reconstruction are evaluated through varying parameters in the beamforming procedures, i.e. steering position, steering window length and source speed for a moving periodic signal using DSB, and regularization parameter, signal to noise ratio (SNR), steering window length, source speed, array to source motion trajectory and mismatch for a moving engine signal using CB. The parameter studies show guidelines of parameter selection based on the given situations in this thesis for modeling moving source using beamforming. Both algorithms are able to reconstruct the moving signals in the given scenarios. Although CB outperforms DSB in terms of signal reconstruction under particular conditions, the localization abilities of the two algorithms are quite similar. The practicability of the model has been applied on pass-by measurements of a moving loudspeaker using the designed arrays, and the results can match the conclusions drawn above from simulations. Finally, a framework on how to apply the model for moving source auralization is proposed.
    Keywords: Science ; Chemistry ; Technology & Engineering ; Construction ; Technology & Engineering ; thema EDItEUR::P Mathematics and Science::PN Chemistry ; thema EDItEUR::T Technology, Engineering, Agriculture, Industrial processes::TN Civil engineering, surveying and building::TNK Building construction and materials ; thema EDItEUR::T Technology, Engineering, Agriculture, Industrial processes::TB Technology: general issues
    Language: English
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  • 44
    Publication Date: 2024-04-05
    Description: Neuere Erkenntnisse zum Umsatzverhalten an Dieseloxidationskatalysatoren (DOCs) zeigen, dass das Umsatzverhalten von Schadstoffen vom Oxidationsgrad der verwendeten Edelmetallkatalysatoren abhängen kann. Dabei wird deutlich, dass sich der Oxidationsgrad bei typischen Abgaszusammensetzungen langsam und reversibel mit der Katalysatortemperatur ändert. Das kann bei periodischen Katalysatortemperaturänderungen zu einem ausgeprägten Hystereseverhalten führen. Bisherige Ergebnisse liegen insbesondere zum Verhalten der NO-Oxidation an Platin-Katalysatoren vor. Ziel der vorliegenden Arbeit ist es daher, die Untersuchungen auf seriennahe Pd- und PtPd-Mischkatalysatoren sowie auf andere abgastypische Schadstoffe, wie CO und Kohlenwasserstoffe, zu erweitern und dabei auch den Einfluss der Katalysatoralterung zu erfassen. Es wurde ein globalkinetisches Modell entwickelt und an die experimentellen Befunde angepasst. Dabei zeigte sich, dass es in der Regel möglich ist, das Umsatzverhalten bei reinen Pt- und Pd-Katalysatoren mit diesem örtlich eindimensionalen, makrokinetischen Zweiphasenmodell zutreffend zu beschreiben, wohingegen das Verhalten auf Pt/Pd-Mischkatalysatoren weniger gut simuliert werden kann. Dies ist vermutlich auf die heterogene Struktur der Pt/Pd-legierten Partikel zurückzuführen.
    Keywords: Science ; Chemistry ; Technology & Engineering ; Chemical & Biochemical ; thema EDItEUR::P Mathematics and Science::PN Chemistry ; thema EDItEUR::T Technology, Engineering, Agriculture, Industrial processes::TD Industrial chemistry and manufacturing technologies::TDC Industrial chemistry and chemical engineering
    Language: German
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  • 45
    Publication Date: 2023-03-08
    Description: © The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in LeClerc, H., Tompsett, G., Paulsen, A., McKenna, A., Niles, S., Reddy, C., Nelson, R., Cheng, F., Teixeira, A., & Timko, M. Hydroxyapatite catalyzed hydrothermal liquefaction transforms food waste from an environmental liability to renewable fuel. IScience, 25(9), (2022): 104916, https://doi.org/10.1016/j.isci.2022.104916.
    Description: Food waste is an abundant and inexpensive resource for the production of renewable fuels. Biocrude yields obtained from hydrothermal liquefaction (HTL) of food waste can be boosted using hydroxyapatite (HAP) as an inexpensive and abundant catalyst. Combining HAP with an inexpensive homogeneous base increased biocrude yield from 14 ± 1 to 37 ± 3%, resulting in the recovery of 49 ± 2% of the energy contained in the food waste feed. Detailed product analysis revealed the importance of fatty-acid oligomerization during biocrude formation, highlighting the role of acid-base catalysts in promoting condensation reactions. Economic and environmental analysis found that the new technology has the potential to reduce US greenhouse gas emissions by 2.6% while producing renewable diesel with a minimum fuel selling price of $1.06/GGE. HAP can play a role in transforming food waste from a liability to a renewable fuel.
    Description: This work was funded by the DOE Bioenergy Technology Office (DE-EE0008513), a DOE DBIR (DE-SC0015784) and the MassCEC. The authors thank WenWen Yao, Department of Environmental Science at WPI, for TOC analysis, Mainstream Engineering for heating value characterization of the oil and solid samples, Wei Fan for assistance in obtaining SEM images and, Julia Martin and Ronald Grimm for their assistance in collecting XPS data, and Jeffrey R. Page for his assistance with oil upgrading and analysis. HOL was partially funded for this work by NSF Graduate Research Fellowship award number 2038257. A portion of this work was performed at the National High Magnetic Field Laboratory Ion Cyclotron Resonance user facility, which is supported by the NSF Division of Materials Research and Division of Chemistry through DMR 16-44779 and the State of Florida.
    Keywords: Chemistry ; Chemical engineering ; Catalysis
    Repository Name: Woods Hole Open Access Server
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  • 46
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    In:  Other Sources
    Publication Date: 2019-07-12
    Description: The rate of heat transfer between a fluid stream in turbulent flow and a smooth, solid wall is largely controlled by the relatively high resistance of the laminar sublayer next to the wall. Although this laminar layer ii extremely thin, heat can be transferred through it only by molecular diffusion. Hence the resistance of this layer is very much greater than for a layer the same thickness farther out in the stream where turbulent exchange is the controlling factor. The thickness of the laminar layer is difficult to define precisely, since there is a gradual transition to the turbulent flow outside, but for the usual scale of many engineering applications almost half the temperature difference between the fluid and the wall occurs in a layer of a few thousands of an inch in thickness. When the wall is made of porous material and a coolant gas is forced through the wall into the stream, it has been found that a very small flow rate of the coolant is remarkably effective in keeping the wall at a low temperature. The coolant flow rate required is such as to give an average velocity normal cooling wall of the order of 1 per cent of the main stream velocity. This flow rate is so low that clearly the injected gas must act as an insulator rather than as a normal coolant. Because of its relatively low velocity, the injected gas can have very little influence on heat convection or momentum transfer in the turbulent stream, and its effect must be confined to the laminar sublayer. The possible influence of the coolant flow on the thickness of the laminar layer will be discussed in Section V.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: JPL-PR-4-50
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  • 47
    Publication Date: 2019-07-11
    Description: A large number of papers have been devoted to the problem of integration of equations of two-dimensional steady nonvertical adiabatic motion of a gas. Most of these papers are based on the application of the hodograph method of S. A. Chaplygin in which the plane of the hodograph of the velocity is taken as the region of variation of the independent variables in the equations of motion; the equations become linear in this plane. The exact integration of these equations is, however, obtained in the form of infinite series containing hypergeometric functions. The obtaining of such solutions and their investigation involves extensive computations. As a result, methods have been developed for the approximate integration of the equations of motion first transformed to a linear form. S. A. Chaplygin first pointed out such an approximate method applicable to flows in which the Mach number does not exceed 0.4.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1239 , Prikladnaia Matematika I Mekhanika, Tom XI
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  • 48
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    In:  CASI
    Publication Date: 2019-07-11
    Description: A study is made herein of the irrotational adiabatic motion of a gas in the transition from subsonic to supersonic velocities. A shape of the de Laval nozzle is given, which transforms a homogeneous plane-parallel flow at large subsonic velocity into a supersonic flow without any shockwaves beyond the transition line from the subsonic to the supersonic regions of flow. The method of solution is based on integration near the transition line of the gas equations of motion in the form investigated by S. A. Christianovich.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1236 , Prikladnaia Matematika I Mekhanika, Tom XI
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  • 49
    Publication Date: 2019-07-11
    Description: By means of characteristics theory, formulas for the numerical treatment of stationary compressible supersonic flows for the two-dimensional and rotationally symmetrical cases have been obtained from their differential equations.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1211 , ZWB Forschungsbericht; Rept-1581
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  • 50
    Publication Date: 2019-07-11
    Description: The turbulent flow in a conical diffuser represents the type of turbulent boundary layer with positive longitudinal pressure gradient. In contrast to the boundary layer problem, however, it is not necessary that the pressure distribution along the limits of the boundary layer(along the axis of the diffuser) be given, since this distribution can be obtained from the computation. This circumstance, together with the greater simplicity of the problem as a whole, provides a useful basis for the study of the extension of the results of semiempirical theories to the case of motion with a positive pressure gradient. In the first part of the paper,formulas are derived for the computation of the velocity and.pressure distributions in the turbulent flow along, and at right angles to, the axis of a diffuser of small cone angle. The problem is solved.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1137 , Central Aero-Hydrodynaical Institute Reports; Rept-462
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  • 51
    Publication Date: 2019-07-12
    Description: Strain gages were used to measure blade vibrations possibly causing failure in the 10-stage compressor of the 19XB jet-propulsion engine. The seventh and tenth stages were of great concern as a result of failures experienced by the manufacturer. Strain-gage records were obtained from all stages during acceleration, deceleration, and constant speed runs. Curves are presented herein showing the maximum allowable vibratory stress for a given speed, the change of the damping coefficient with the mounting of a strain gage at the base of the blade, the effect of rotor speed, on blade natural frequency, and the effect of the order of first bending-mode vibration on stress. It was found that for all stages the lower the order of vibration the higher the stress but no destructive vibrations were detected.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-RM-SE8A28
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  • 52
    Publication Date: 2019-07-12
    Description: An investigation has been conducted on a one-sixth segment of an annular turbojet combustor to determine the effects of modification in air-flow distribution and total-pressure loss on the performance of the segment. The performance features investigated during this series of determinations were the altitude operational limits and the temperature-rise efficiency. Altitude operational limits of the combustor segment, for the 19XB engine using the original combustor-basket design were approximately 38,000 feet at 17,000 rpm and 26,000 feet at 10,000 rpm. The altitude operational limits were approximately 50,000 feet at 17,000 rpm and 38,000 feet at 10,000 rpm for a combustor-basket design in which the air-passage area in the basket was redistributed so as to admit gradually no more than 20 percent of the air along the first half of the basket. In this case the total pressure loss through the combustor segment was not appreciably changed from the total-pressure loss for the original combustor basket design. Altitude operational limits of the combustor segment for the 19XB engine were above 52,000 feet at 17,000 rpm and were approximately 23,000 feet at 10,000 rpm for a combustor-basket design in which the distribution of the air-passage area in the basket was that of the original design but where the total-pressure loss was increased to 19 times the inlet reference kinetic pressure at an inlet-to-outlet density ratio of 2.4. The total-pressure loss for the original design was 14 times the inlet kinetic reference pressure at an inlet-to-outlet density ratio of 2.4.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-RM-SE7K16
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  • 53
    Publication Date: 2019-08-13
    Description: A heat-transfer investigation was conducted with air flowing through an electrically heated silicon carbide tube with a rounded entrance, an inside diameter of 3/4 inch, and effective heat-transfer length of 12 inches over a range of Reynolds numbers up to 300,000 and a range of average inside-tube-wall temperatures up to 2500 R. The highest corresponding local outside-tube-wall temperature was 3010 R.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA/RM-E9D12
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  • 54
    Publication Date: 2019-07-11
    Description: The calculation of the phenomena within the boundary layer of bodies immersed in a flow underwent a decisive development on the basis of L. Prandtl's trains of thought, stated more than forth years ago, and by numerous later treatises again and again touching upon them. The requirements of the steadily improving aerodynamics of airplanes have greatly increased with the passing of time and recently research became particularly interested in such phenomena in the boundary layer as are caused by small external disturbances. Experimental results suggest that, for instance, slight fluctuations in the free stream velocities as they occur in wind tunnels or slight wavelike deviations of outer wing contours from the prescribed smooth course as they originate due to construction inaccuracies may exert strong effects on the extent of the laminar boundary layer on the body and thus on the drag. The development of turbulence in the last part of the laminar portion of the boundary layer is, therefore, the main problem, the solution of which explains the behavior of the transition point of the boundary layer. A number of reports in literature deal with this problem,for instance, those of Tollmien, Schlichting, Dryden, and Pretsch. The following discussion of the behavior of the laminar boundary layer for periodically oscillating pressure variation also purports to make a contribution to that subject.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1228 , Ludwig Prandtl zum 70. Geburtstage, Schriften der Deutschen Akademie der Luftfahrtforschung, Publications of the Germany academy for Aviation Research; 247-255
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  • 55
    Publication Date: 2019-07-11
    Description: Some aerodynamic relations are derived which exist between two infinitely long airfoils if one is in a straight flow and the other in oblique flow, and both present the same profile in the direction of flow.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1158 , Deutsche Luftfahrtforschung, Forschungsbericht; Rept-1497
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  • 56
    Publication Date: 2019-07-11
    Description: At the request of the Junkers Aircraft and Engine Construction Company, Engine Division, Dessau Main Plant, an investigation was made using the interferometer method on the two turbine-blade profiles submitted. The interferometer method enables making visible the differences in density and consequently the boundary layers that develop when a flow is directed on the profile. Recognition of the points on the profile at which separation of flow occurs is thus possible. By means of the interference photographs the extent of the dead-water region may be ascertained. The size of the dead-water region provides evidence as to the quality of the flow and allows a qualitative estimate of the amount of the flow losses. Interference photographs thus provide means of judging the utility of profiles under specific operating conditions and provide suggestions for possible changes of profile contours that might help to improve flow relations. Conclusions may be drawn concerning the influence of the blade-spacing ratio, the inlet-air angle, and the connection between the curvature of the profile contour and the point of separation of the flow from the profile surface.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1171 , Deutsche Luftfahrtforschung, Untersuchungen und Mitteilungen; Rept-2096
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  • 57
    Publication Date: 2019-07-11
    Description: The cavitation in nozzles on airfoils of various shape and on a sphere are experimentally investigated. The limits of cavitation and the extension of the zone of the bubbles in different stages of cavitation are photographically established. The pressure in the bubble area is constant and very low, jumping to high values at the end of the area. The analogy with the gas compression shock is adduced and discussed. The collapse of the bubbles under compression shock produces very high pressures internally, which must be contributory factors to corrosion. The pressure required for purely mechanical corrosion is also discussed.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1078 , Eidgenoessische Technische Hochschule
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  • 58
    Publication Date: 2019-07-11
    Description: This paper includes the following topics: 1) Characteristic differential equations; 2) Treatment of practical examples; 3) First example: Diffuser; and 4) Second Example: Nozzle.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1244 , Chapter 4, Technische Hoschschule Dresden, Archives No. 44; Rept-44/4
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  • 59
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    In:  CASI
    Publication Date: 2019-07-11
    Description: This paper contains a tabulation of functions of the Mach number which are frequently used in high-speed aerodynamics. The tables extend from M = 0 to M = 10.0 in increments of 0.01 and are based on the assumption that air is a perfect gas having a specific heat ratio of 1.400.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-RM-L7K26
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  • 60
    Publication Date: 2019-08-14
    Description: The conference on Turbojet-Engine Thrust-Augmentation Research was organized by the NACA to present in summarized form the results of the latest experimental and analytical investigations conducted at the Lewis Flight Propulsion Laboratory on methods of augmenting the thrust of turbojet engines. The technical discussions are reproduced herewith in the same form in which they were presented. The original presentation in this record are considered as complementary to, rather than substitutes for, the committee's system of complete and formal reports.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA Conference on Turbojet-Engine Thrust - Augmentation Research; Oct 28, 1948; Cleveland, OH; United States
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  • 61
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    In:  CASI
    Publication Date: 2019-07-13
    Description: The condensation of water vapor in an air consequences: acquisition of heat (liberated heat vaporization; loss of mass on the part of the flowing gas (water vapor is converted to liquid); change in the specific gas constants and of the ratio k of the specific heats (caused by change of gas composition). A discontinuous change of state is therefore connected with the condensation; schlieren photographs of supersonic flows in two-dimensional Laval nozzles show two intersecting oblique shock fronts that in the case of high humidities may merge near the point of intersection into one normal shock front.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1174 , Heeres-Versuchsstelle; 66/72
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  • 62
    facet.materialart.
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    In:  CASI
    Publication Date: 2019-07-13
    Description: The recent experiments by Jakob and Erk, on the resistance of flowing water in smooth pipes, which are in good agreement with earlier measurements by Stenton and Pannell, have caused me to change my opinion that the empirical Blasius law (resistance proportional to the 7/4 power of the mean velocity) was applicable up to arbitrarily high Reynolds numbers. According to the new tests the exponent approaches 2 with increasing Reynolds number, where it remains an open question whether or not a specific finite limiting value of the resistance factor lambda is obtained at R = infinity. With the collapse of Blasius' law the requirements which produced the relation that the velocity in the proximity of the wall varied in proportion to the 7th root of the wall distance must also become void. However, it is found that the fundamental assumption that led to this relationship can be generalized so as to furnish a velocity distribution for any empirical resistance law. These fundamental assumptions can be so expressed that for the law of velocity distribution in proximity of the wall as well as for that of friction at the wall, a form can be found in which the pipe diameter no longer occurs, or in other words, that the processes in proximity of a wall are not dependent upon the distance of the opposite wall.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1231 , Zeitschrift fuer Angewandte Matematik und Mechanik; 5; 2; 136-139
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  • 63
    facet.materialart.
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    In:  CASI
    Publication Date: 2019-07-13
    Description: The flow about a conical body of an ideal compressible fluid is considered. Assume that the velocity of the oncoming flow at infinity W is directed along the z-axis. The system of Cartesian coordinates x, y, z with origin at the vertex of the cone O is shown. From the considerations,of the dimensional theory, it may be found that along any ray issuing from O the components of the velocity u, v, W+w along the coordinate axes will maintain a constant value. It is further assumed that the conical body has such shape and disposition relative to the flow that u, v, and w are small in comparison with W.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1245 , Prikladnaya Matematika I Mekhanika; X; 513-520
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  • 64
    Publication Date: 2019-07-13
    Description: For a certain Mach number of the oncoming flow, the local velocity first reaches the value of the local velocity of sound (M = 1) at some point on the surface of the body located within the flow. This Mach number is designated the critical Mach number M(sub cr). By increasing the flow velocity, a supersonic local region is formed bounded by the body contour and the line of transition from subsonic to supersonic velocity. As is shown by observations with the Toepler apparatus, at a certain flow Mach number M 〉 M(sub cr) a shock wave is formed near the body that closes the local supersonic region from behind. The formation of the shock wave is associated with the appearance of an additional resistance defined as the wave drag. In this paper, certain features are described of the flow in the local supersonic region, which is bounded by the contour of the body and the transition line, and conditions are sought for which the potential flow with the local supersonic region becomes impossible and a shock wave occurs. In the first part of the paper, the general properties of the potential flow in the local supersonic region, bounded by the contour of the profile and the transition line, are established. It is found that at the transition line, if it is not a line of discontinuity, the law of monotonic variation of the angle of inclination of the velocity vector holds (monotonic law). An approximation is given for the change in velocity at the contour of the body. The flow about a contour having a straight part is studied. In the second part of the paper, an approximation is given of the magnitudes of the accelerations at the interior points of the supersonic region. With the aid of these approximations, it is shown that for profiles convex to the flow the breakdown of the potential flow,associated with an increase of the Mach number of the oncoming flow, cannot be due to the formation of an envelope of the characteristics within the supersonic region. On the basis of the monotonic law, the transitional Mach number M is found, beyond which the potential flow with local supersonic region becomes impossible.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1213 , Prikladnaya Matematika i Mekhanika; 10; 4; 481-502
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  • 65
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    In:  CASI
    Publication Date: 2019-07-13
    Description: In the present paper, the motion of a gas in a plane-parallel Laval nozzle in the neighborhood of the transition from subsonic to supersonic velocities is studied. In a recently published paper, F. I. Frankl, applying the holograph method of Chaplygin, undertook a detailed investigation of the character of the flow near the line of transition from subsonic to supersonic velocities. From the results of Tricomi's investigation on the theory of differential equations of the mixed elliptic-hyperbolic type, Frankl introduced as one of the independent variables in place of the modulus of the velocity, a certain specially chosen function of this modulus. He thereby succeeded in explaining the character of the flow at the point of intersection of the transition line and the axis of symmetry (center of the nozzle) and in studying the behavior of the stream function in the neighborhood of this point by separating out the principal term having, together with its derivatives, the maximum value as compared with the corresponding corrections. This principal term is represented in Frankl's paper in the form of a linear combination of two hypergeometric functions. In order to find this linear combination, it is necessary to solve a number of boundary problems, which results in a complex analysis. In the investigation of the flow with which this paper is concerned, a second method is applied. This method is based on the transformation of the equations of motion to a form that may be called canonical for the system of differential equations of the mixed elliptic-hyperbolic type to which the system of equations of the motion of an ideal compressible fluid refers. By studying the behavior of the integrals of this system in the neighborhood of the parabolic line, the principal term of the solution is easily separated out in the form of a polynomial of the third degree. As a result, the computation of the transitional part of the nozzle is considerably simplified.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1212 , Prikladnaya Matematika I Mekhanika; 10; 4; 503-512
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  • 66
    Publication Date: 2019-07-13
    Description: There are investigated the problems of the flow of a supersonic jet out of a vessel with plane side walls and the problem of the supersonic flow about a wedge when there is a zone of local subsonic velocities ahead of the wedge.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1155 , Bulletin de L'Academie des Sciences de L'URSS; 9; 121-143
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  • 67
    Publication Date: 2019-07-11
    Description: This paper makes the following assumptions: 1) The flowing gases are assumed to have uniform energy distribution. ("Isoenergetic gas flows," that is valid with the same constants for the the energy equation entire flow.) This is correct, for example, for gas flows issuing from a region of constant pressure, density, temperature, end velocity. This property is not destroyed by compression shocks because of the universal validity of the energy law. 2) The gas behaves adiabatically, not during the compression shock itself but both before and after the shock. However, the adiabatic equation (p/rho(sup kappa) = C) is not valid for the entire gas flow with the same constant C but rather with an appropriate individual constant for each portion of the gas. For steady flows, this means that the constant C of the adiabatic equation is a function of the stream function. Consequently, a gas that has been flowing "isentropically",that is, with the same constant C of the adiabatic equation throughout (for example, in origination from a region of constant density, temperature, and velocity) no longer remains isentropic after a compression shock if the compression shock is not extremely simple (wedge shaped in a two-dimensional flow or cone shaped in a rotationally symmetrical flow). The solution of nonisentropic flows is therefore an urgent necessity.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1187 , Rept-44/1
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  • 68
    Publication Date: 2019-07-11
    Description: The authors regret that due to the lack of time the investigations could not be carried out to a more finished form. Especially in the first part it was intended to include a few further applications and to use them in the general considerations of this part. In spite of the fact that the intentions of the authors could not be realized, the authors felt that it would serve the aims of the competition to present part I in its present fragmentary form. The topics include: 1) A Few General Remarks Covering the Prandtl-Busemann Method; and 2) Effect of Compressibility in Axially Symmetrical Flow around an Ellipsoid.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1233 , Lilienthal-Gesellschaft fuer Luftfahrtforschung Bericht S 13/1, Part 1; 40-68; Rept-13/1
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  • 69
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    In:  CASI
    Publication Date: 2019-07-11
    Description: In the present paper which deals with the heat transfer between the gas and the wall for large temperature drops and large velocities use is made of the method of Dorodnitsyn of the introduction of a new independent variable, with this difference, however, that the relation between the temperature field (that is, density) and the velocity field in the general case considered is not assumed given but is determined from the solution of the problem. The effect of the compressibility arising from the heat transfer is thus taken into account (at the same time as the effect of the compressibility at the large velocities). A method is given for determining the coefficients of heat transfer and the friction coefficients required in many technical problems for a curved wall in a gas flow at large Mach numbers and temperature drops. The method proposed is applicable both for Prandtl number P = 1 and for P not equal to 1.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1229 , Prikladnaya Matematika I Mekhanika, Tom X; 449-474
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  • 70
    Publication Date: 2019-07-11
    Description: The present report consists of two parts. The first part deals with the two-dimensional stationary flow in the presence of local supersonic zones. A numerical method of integration of the equation of gas dynamics is developed. Proceeding from solutions at great distance from the body the flow pattern is calculated step by step. Accordingly the related body form is obtained at the end of the calculation. The second part treats the relationship between the displacement thickness of laminar and turbulent boundary layers and the pressure distribution at high speeds. The stability of the boundary layer is investigated, resulting in basic differences in the behavior of subsonic and supersonic flows. Lastly, the decisive importance of the boundary layer for the pressure distribution, particularly for thin profiles, is demonstrated.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1189 , Lilienthal-Gesellschaft fuer Luftfahrtforschung Bericht S13/1 Teil; 7-24
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  • 71
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    In:  CASI
    Publication Date: 2019-07-11
    Description: There has been under development for the high-speed wind tunnel of the LFA an optical measuring arrangement for the qualitative and quantitative investigation of flow. By the use of interference measurements, the determination of density at the surface of the bodies being tested in the air stream and in the vicinity of these bodies can be undertaken. The results obtained so far in the simple preliminary investigations show that it is possible, even at a low Reynolds number, to obtain the density field in the neighborhood of a test body by optical means. Simple analytical expressions give the relation between density, pressure, velocity, and temperature. In addition to this, the interference measurement furnishes valuable data on the state of the boundary layer, that is, the sort of boundary layer (whether laminar or turbulent), as well as the temperature and velocity distribution.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1253 , Forschungsbericht; Rept-1167
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  • 72
    facet.materialart.
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    In:  CASI
    Publication Date: 2019-07-11
    Description: It is known that compression shocks which lead from supersonic to subsonic velocity cause the flow to separate on impact on a rigid wall. Such shocks appear at bodies with circular symmetry or wing profiles on locally exceeding sonic velocity, and in Laval nozzles with too high a back pressure. The form of the compression shocks observed therein is investigated.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1150 , Deutsche Luftfahrtforschung; Rept-1850
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  • 73
    Publication Date: 2019-07-11
    Description: The characteristics of the position and form of the transition surface through the critical velocity are computed for flow through flat and round nozzles from subsonic to supersonic velocity. Corresponding considerations were carried out for the flow about profiles in the vicinity of sonic velocity.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1147 , Deutsche Luftfahrtforchung; Rept-1992
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  • 74
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    In:  CASI
    Publication Date: 2019-07-11
    Description: The flow laws of the actual flows at high Reynolds numbers differ considerably from those of the laminar flows treated in the preceding part. These actual flows show a special characteristic, denoted as turbulence. The character of a turbulent flow is most easily understood the case of the pipe flow. Consider the flow through a straight pipe of circular cross section and with a smooth wall. For laminar flow each fluid particle moves with uniform velocity along a rectilinear path. Because of viscosity, the velocity of the particles near the wall is smaller than that of the particles at the center. i% order to maintain the motion, a pressure decrease is required which, for laminar flow, is proportional to the first power of the mean flow velocity. Actually, however, one ob~erves that, for larger Reynolds numbers, the pressure drop increases almost with the square of the velocity and is very much larger then that given by the Hagen Poiseuille law. One may conclude that the actual flow is very different from that of the Poiseuille flow.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1218
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  • 75
    facet.materialart.
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    In:  CASI
    Publication Date: 2019-07-11
    Description: Contents include the following: Characteristic differential equations - initial and boundary conditions. Integration of the second characteristic differential equations. Direct application of Meyer's characteristic hodograph table for construction of two-dimensional potential flows. Prandtl-Busemann method. Development of the pressure variation for small deflection angles. Numerical table: relation between deflection, pressure, velocity, mach number and mach angle for isentropic changes of state according to Prandtl-Meyer for air (k = 1.405). References.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1243 , Chapter 3,Technische Hochschule Dresden, Archives No. 44/3; Rept-44/3
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  • 76
    Publication Date: 2019-07-11
    Description: Six, 3-inch-chord symmetrical airfoil sections having systematic variations in thickness and thickness location were tested at Mach numbers near flight values for propeller-shank sections. The tests, the results of which are presented in the form of schlieren photographs of the flow past each model and pressure-distribution charts for two of the model, were performed to illustrate the effects of compressibility on the flow past thick symmetrical airfoil sections. Representative flow photographs indicated that at Mach numbers approximately 0.05 above the critical Mach number a speed region was reached in which the flow oscillated rapidly and the separation point and the location of the shock wave were unstable. Fixing the transition on both surfaces of the airfoil was effective in reducing these rapid oscillations. The pressure distributions showed that the section normal-force coefficients for thick airfoils were very erratic at subcritical speeds; at supercritical speeds the section normal-force coefficients for the thick airfoils became more regular. Drag coefficients showed that considerable drag decreases can be expected by decreasing the model thickness ratio.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-RM-L6J17a
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  • 77
    Publication Date: 2019-07-11
    Description: A heat-transfer investigation was conducted with air flowing through an electrically heated silicon carbide tube with a rounded entrance, an inside diameter of 3/4 inch, and an effective heat-transfer length of 12 inches over a range of Reynolds numbers up to 300,000 and a range of average inside-tube-wall temperature up to 2500 R. The highest corresponding local outside-tube-wall temperature was 3010 R. Correlation of the heat-transfer data using the conventional Nueselt relation wherein physical properties of the fluid were evaluated at average bulk temperature resulted in a separation of data with tube-wall-temperature level. A satisfactory correlation of the heat-transfer data was obtained, however, by the use of modified correlation parameters wherein the mass velocity G (or product of average air density and velocity evaluated at bulk temperature P(sub b)V(sub b)) in the Reynolds number was replaced by the product of average air velocity evaluated at the bulk temperature and density evaluated at either the average inside-tube-wall temperature or the average film temperature; in addition, all the physical properties of air were correspondingly evaluated at either the average inside-tube-wall temperature or the average film temperature.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-RM-E9D12-Pt-3 , Rept-1115-Pt-3
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  • 78
    Publication Date: 2019-07-10
    Description: In the lecture series starting today author want to give a survey of a field of aerodynamics which has for a number of years been attracting an ever growing interest. The subject is the theory of flows with friction, and, within that field, particularly the theory of friction layers, or boundary layers. A great many considerations of aerodynamics are based on the ideal fluid, that is the frictionless incompressibility and fluid. By neglect of compressibility and friction the extensive mathematical theory of the ideal fluid, (potential theory) has been made possible. Actual liquids and gases satisfy the condition of incomressibility rather well if the velocities are not extremely high or, more accurately, if they are small in comparison with sonic velocity. For air, for instance, the change in volume due to compressibility amounts to about 1 percent for a velocity of 60 meters per second. The hypothesis of absence of friction is not satisfied by any actual fluid; however, it is true that most technically important fluids, for instance air and water, have a very small friction coefficient and therefore behave in many cases almost like the ideal frictionless fluid. Many flow phenomena, in particular most cases of lift, can be treated satisfactorily, - that is, the calculations are in good agreement with the test results, -under the assumption of frictionless fluid. However, the calculations with frictionless flow show a very serious deficiency; namely, the fact, known as d'Alembert's paradox, that in frictionless flow each body has zero drag whereas in actual flow each body experiences a drag of greater or smaller magnitude. For a long time the theory has been unable to bridge this gap between the theory of frictionless flow and the experimental findings about actual flow. The cause of this fundamental discrepancy is the viscosity which is neglected in the theory of ideal fluid; however, in spite of its extraordinary smallness it is decisive for the course of the flow phenomena.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1217
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  • 79
    Publication Date: 2019-07-12
    Description: Wind-tunnel tests of a full-scale model of the Republic XF-91 airplane having swept-back wings and a vee tail were conducted to determine both the stability and control characteristics of the model longitudinally, laterally, and directionally. Configurations of the model were investigated involving such variables as external fuel tanks, a landing gear, trailing-edge flaps, leading-edge slats, and a range of wing incidences and tail incidences.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-RM-SA9C04
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  • 80
    Publication Date: 2019-08-16
    Description: Characteristic methods for nonstationary flows have been published only for the special case of the isentropic flow up until the present, althought they are applicable in various places to more difficult questions too. This report derives the characteristic method for the flows which depend only on the position coordinates and time. At the same time the treatment of compression shocks is shown.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1196 , Zentrale fuer Wissenschaftliches Berichtswesen der Luftfahrtforschung des Generalluftzeugmeisters (ZWB); 1744
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  • 81
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    In:  CASI
    Publication Date: 2019-08-16
    Description: The investigation of the flow in a centrifugal pump indicated that the flow patterns in frictional fluid are fundamentally different from those in frictionless fluid. In particular, the dead air space adhering to the section side undoubtedly causes a reduction of the theoretically possible delivery head. The velocity distribution over a parallel circle is also subjected to a noticeable change as a result of the incomplete filling of the passages. The relative velocity on the pressure side of the vane, which for passages completely filled with active flow would differ little from zero even at comparatively lower than normal delivery volume, is increased, so that no rapid reverse flow occurs on the pressure side of the vane even for smaller delivery volume. It was established, further, that the flow ceases to be stationary for very small quantities of water. The inflow to the impeller can be regarded as radial for the operating range an question. The velocity triangles at the exit are subjected to a significant alteration in shape ae a result of the increased peripheral velocity, which may be of particular importance in the determination of the guide vane entrance angle.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1089 , Mitteilungen des Hydraulischen Instituts der Technischen Hochschule; 4; 1-27
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  • 82
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    In:  CASI
    Publication Date: 2019-08-15
    Description: On the basis of certain formulas recently established by L. Prandtl for the turbulent interchange of momentum in stationary flows, various cases of "free turbulence" - that is, of flows without boundary walls - are treated in the present report. Prandtl puts the apparent shearing stress introduced by the turbulent momentum interchange. This present report deals first with the mixing of an air stream of uniform velocity with the adjacent still air, than with the expansion or diffusion of an air jet in the surrounding air space.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1085 , Zeitschrift fuer angewandte Mathematik und Mechanik; 6; 1-12
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  • 83
    Publication Date: 2019-08-15
    Description: As a turbine rotor turns, the blades traverse the wake zones of the nozzle vanes. A periodic fluctuation of the pressure distribution around the circumference of the rotor blade is therefore caused. It was desired to investigate quantitatively this effect. At the same time, the magnitude of the force acting upon one profile of the rotor-blade lattice at various positions of this lattice relative to the nozzle lattice was to be determined.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1173 , Reports of the Lattice Conference: Berichte der Gittertagung; Mar 27, 1944 - Mar 27, 1944; Brunswick,; Germany|Berichte der Gittertagung; 95-100; M325/44g
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  • 84
    Publication Date: 2019-07-12
    Description: The heat losses from the envelope surface of a U.S. Navy K-type airship are evaluated to determine if the use of heat is a feasible means of preventing ice and snow accumulations on lighter-than-air craft during flight and when moored uncovered. Consideration is given to heat losses in clear air (no liquid water present in the atmosphere) and in probable conditions of icing and snow. The results of the analysis indicate that the amount of heat required in flight to raise the surface temperature of the entire envelope to the extent considered adequate for ice protection, based on experience with tests of heavier-than-air craft, is very large. Existing types of heating equipment which could be used to supply this quantity of heat would probably be too bulky and heavy to provide a practical flight installation. The heat requirements to provide protection for the nose and stern regions in assumed mild to moderate icing conditions appear to be within the range of the capacity of current types of heating equipment suitable for flight use. The amount of heat necessary to prevent snow accumulations on the upper surface of the airship envelope when moored uncovered under all conditions appear to be excessive for the heating equipment presently available for flight use, but could possibly be achieved with auxiliary ground heating equipment.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-RM-SA6L20
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  • 85
    Publication Date: 2019-07-13
    Description: Test results are present for cascades of airfoils in retarded flow and increasing pressure as corresponds to the case of the impeller of an axial propeller pump and propeller fan.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1190 , Transactions of the Society of Mechanical Engineers; 3; 13; 334-344
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  • 86
    facet.materialart.
    Unknown
    In:  CASI
    Publication Date: 2019-07-13
    Description: With water as driving medium and delivered medium in a device similar to a simple jet apparatus, the pressure and velocity fields of the mixing zone were explored with a pitot bar; the ratio of delivered to driving volume ranged between the values 0, 1, 2, and 4. An attempt was also made to analyze the mixing flow mathematically by integration of the equation of motion, with the aid of conventional formulas for the turbulent shearing stress, but this succeeded only approximately for the very simplified case that a driving jet is introduced in an unlimited parallel flow, while the pressure over the whole mixing field is assumed to be constant. In spite of these dissimilar assumptions for the theory and the experiment, the form of the measured and the computed velocity profiles indicates a very high degree of approximation. The pressure rise, which was approximated by Flugel's formulas, disclosed good agreement with the measured values.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1096 , Forschung auf dem Gebiete des Ingenieurwesens; 12; 1; 16-30
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  • 87
    facet.materialart.
    Unknown
    In:  CASI
    Publication Date: 2019-07-13
    Description: The characteristics introduced by the turbulence in the process of the flame propagation are considered. On the basis of geometrical and dimensional considerations an expression is obtained for the velocity of the flame propagation in a flow of large scale of turbulence.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1110 , Journal of Technical Physics; 13; 10-Sep
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  • 88
    Publication Date: 2019-07-13
    Description: On the basis of photographic pictures the laminar flow at a pipe inlet was measured and compared with other measurements and computational results. The test setup is described in detail, and a series of the pictures obtained for turbulent flow is given.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1109 , Forschung auf dem Gebiete des Ingenieurwesens; 8; Pt 1; 42-47
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  • 89
    Publication Date: 2019-07-13
    Description: The present report deals with the effect of turbulence on the propagation of the flame. Being based upon experiments with laminar as well as turbulent Bunsen flames, both the physico-chemical and the hydro-dynamical aspects of the problem are analyzed. A number of new deductions, interesting from the point of view of engine combustion and other very rapidly changing flame reactions, are made.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1112 , Zeitschrift fuer Elektrochemie und Angewandte Physikalische Chemiw; 46; 11; 601-626
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  • 90
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Diethyl silicon dichloride was prepared by a Grignard synthesis and purified highly. The material in various stages of purification was hydrolyzed and then polymerized. The properties of the hydrolyzate and of the final polymer depended markedly upon the degree of purification of the dichloride. The reaction of diethylsilicanediol with phosphorous pentoxide was also studied; the predominating reaction appears to involve entrance of the pentoxide into the polymeric structure, rather than a simple acceleration of the polycondensation reaction by the removal of water.
    Additional Material: 3 Ill.
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  • 91
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 1 (1946), S. 127-145 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: This and a following article review the literature from 1910-1945 on polymerization of olefins and diolefins in suspension and emulsion, and present a number of new measurements not published to date. The subject is considered mainly from the point of view of scientific information on the mechanism of polymerization in aqueous suspensions and emulsions, but brief mention is also made of the more important disclosures in the patent literature. The new data presented in this article refer to (1) initial rates of polymerization of styrene, methyl methacrylate, vinyl acetate and acrylonitrile in aqueous suspensions and in soap emulsions as a function of catalyst concentration, temperature, and soap concentration; (2) influence of water-soluble activators, such as sodium bisulfite; (3) influence of initial size of monomer droplets on initial rates of monomer consumption; (4) study, with the aid of the electron microscope, of size of monomer droplets and polymer particles throughout polymerization; and (5) a few experiments on side reactions in the domain of higher conversions. No attempt is made in this paper to review and appraise the very large number of recent patents (from about 1930 on), which protect special procedures on the use of various promoting, regulating, or modifying ingredients. A complete digest of this practice does not exist at present, but reference may be made to the excellent chapter on emulsion polymerization in the book of Talalay and Magat (55), to the very valuable compilation of patents by Hosch in “India Rubber World” (27), and to the enumeration of a selected number of patents in the book of Scheiber (50) on pages 210-213.
    Additional Material: 13 Ill.
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  • 92
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 1 (1946), S. 329-339 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A series of experiments on the elastic behavior of various textile materials was carried out. All results are described with the aid of a mechanical model. For this purpose it is necessary to introduce the possibility of a blockade of a part of the model. The elastic properties are characterized by the values of seven independent fundamental constants of the model. The value of one of these constants associated with the blockade can be determined experimentally in a direct way; it is found to be independent of the moisture content. The most important properties of the model correspond with the molecular image of Hermans.
    Additional Material: 11 Ill.
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  • 93
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 1 (1946), S. 353-363 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Mixtures of butadiene and dimethylbutadiene with varying quantities of styrene and acrylonitrile have been copolymerized under various catalytic conditions at 100°C. The formation of cyclic dimers from dienes and vinyl compounds is, in some cases, much more pronounced than the dimerization of the dienes alone. Since the latter is also a kind of Diels-Alder reaction, a series with increasing dienophilic properties can be established from a comparison of the yields of cyclic dimers. From solubility and swelling experiments it is evident that the polymers prepared from butadiene and the vinyl compounds and those from dimethylbutadiene and acrylonitrile are true copolymers. The mechanical properties of the copolymers from butadiene and increasing amounts of a vinyl compound change gradually from those of a rubber to those of the polyvinyl compound. The copolymers from a mixture containing 30% styrene or acrylonitrile are very similar, respectively, to Buna S and Perbunan. Copolymers of the same composition from dimethylbutadiene and acrylonitrile, on the other hand, form a new class of thermoplastics with a much higher temperature of elasticity.
    Additional Material: 12 Ill.
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  • 94
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 1 (1946), S. 364-379 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The copolymerization in emulsion of butadiene with varying amounts of styrene and acrylonitrile and of dimethylbutadiene with the latter vinyl compound has been studied on a laboratory scale. An essential difference between polymeric vinyl compounds and polydienes is the olefinic character of the latter, which leads to typical secondary changes in the polymers originally formed during the completion of the reaction. Such changes are of fundamental importance for the ultimate mechanical properties of polymers and copolymers based on dienes. After a brief discussion of the general theoretical line of thought serving as a base for our experiments, the influence of various factors on the rate of polymerization is pointed out and demonstrated by experiments. The changes in the nitrogen content of copolymers from acrylonitrile and the yields as a function of the reaction time have also been studied. From an investigation of some physical properties, such as solubility and swelling, the existence of true copolymers (of unknown irregularity) has been established. Copolymers from dimethylbutadiene and acrylonitrile represent a new class of olefinic thermoplastics resembling gutta-percha. Abbreviations used are BP (benzoyl peroxide) and DAB (diazoaminobenzene).
    Additional Material: 13 Ill.
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  • 95
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 1 (1946), S. 380-388 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The transversal dimension of the statistical coil formed by a long-chain molecule in solution or in bulk rubber is independent of the longitudinal dimension, h1, of the coil as long as h1 is small compared with the length of the stretched molecule. On the other hand, the lateral dimension of a coil whose longitudinal vector, h1, is oriented in the direction of stretch undergoes a forced contraction during the deformation of bulk rubber. The forced contraction of the transversal dimension is therefore supplying an extra contribution to the entropy change. Its amount has been estimated in earlier work and it influences the numerical factor occurring in the formula connecting the strain-stretch relation for rubber with the molecular weight of the net fragments.
    Additional Material: 1 Ill.
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  • 96
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The course of the reactions of benzoyl peroxide with cyclohexane and cyclohexene may be accounted for by a mechanism involving free radicals and radical chain reactions. With cyclohexane, the average length of the chain hardly exceeds one step and one mole of hydrocarbon reacts with one mole of peroxide. With cyclohexene, chains of two and three steps also occur and about two and one-half moles of hydrocarbon per mole of peroxide take part in the reaction. It is shown that this is due to the one-sided addition of the primary radicals (originating from the peroxide) to the double bond, yielding a new radical without a double bond which can in turn react in the same way with another unsaturated molecule, thus giving rise to polycyclic compounds (chain formation). This polymerization reaction is, however, soon halted by a competitive side reaction involving substitution of the α- (or β)-methylene group, which leaves the double bond intact. In polymerizable vinyl derivatives in which no reactive α-methylene group is present, the competitive reaction cannot occur and the radical chain reaction continues to form a growing chain of interlinked monomeric molecules with annihilation of the double bonds. The two terminal groups of the macromolecules of the final polymerizate are radicals originating from the peroxide used as a catalyst. If a solvent is used, radicals of the latter may also appear occasionally as terminal groups of the polymer. The mechanism of the catalytic action of diacyl peroxides in the polymerization of vinyl derivatives is thus clarified. The molecule linking reaction induced by free radicals in unsaturated compounds also provides an explanation of the action of benzoyl peroxide as a rubber vulcanizer; the peroxide radicals are found as substituents in the rubber molecule.
    Additional Material: 5 Tab.
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  • 97
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 1 (1946), S. 434-436 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: By suitable alteration of the exponent the fit of viscosity-concentration data by a Philippoff type equation may be substantially improved. For a series of cellulose acetate solutions the exponent of best fit appears to be related to the physical properties and chemical type of the solvent.
    Additional Material: 2 Tab.
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  • 98
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
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  • 99
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 1 (1946), S. 175-182 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The ultraviolet absorption of polystyrene, with maximum absorption at 262 mμ, is due to the presence of phenyl residues in the polymer. The specific extinction coefficient is constant, i.e., independent of the molecular weight of the polymer. This shows that the extinction of the phenyl residues is additive. On the basis of this fact, it is shown that the styrene content of a butadiene-styrene copolymer (such as GR-S rubber) can be determined by ultraviolet spectrophotometry. The relative precision of the determination is about 1%, the probable relative accuracy is about 3%.
    Additional Material: 3 Ill.
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  • 100
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A micromethod is described for density determinations of artificial cellulose fibers by the floating method, in carbon tetrachloride in a dry and air-free atmosphere, permitting an accuracy of one part per thousand. The density is derived from the temperature at which the samples neither sink nor float. This temperature varies, with the kind of fiber, between 45° and 65°C. Measurements of the refractive power were carried out simultaneously. The refractivity calculated according to Gladstone and Dale yields slightly lower figures than those found for model fibers in the preceding communication (Part II). The average difference amounts to seven parts per thousand and is ascribed to a systematic error in the density determinations, due to a slight absorption of carbon tetrachloride by the fibers at elevated temperatures. This explanation is supported by experiments. The density of native ramie, of contracted and reoriented ramie, and of several series of rayon fibers spun with increasing stretch, is given. The conclusion is reached that the density is a measure of the percentage of crystalline substances in the fiber and it is shown that there is a correlation between density and sorptive capacity toward water vapor. The percentage of crystalline matter is estimated to be 55-60% in native ramie and 20-25% in rayon.
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