Termodynamik og varme

Bogens emner er grundlaget for termodynamikken, kemiske reaktioner i ligevægt, fasediagrammer og elektrokemi. Begrebet affinitet er tillagt en central rolle gennem hele fremstillingen. Bogen giver en mere dybtgående indføring til faget end det gængse undervisningsmateriale.

Denne anvisning har til formål at danne et detaljeret overblik over de varmeisoleringsmaterialer, der på nuværende tidspunkt er på det danske marked, dels ved at beskrive væsentlige egenskaber, og dels hvordan materialerne kan anvendes i udvalgte bygningsdele. Først behandler anvisningen emnerne dokumentation og egenskaber for varmeisoleringsmaterialer som helhed for at lette sammenligningen på tværs af materialetyper. Det omfatter bl.a. deklarering og CE-mærkning, varmeledningsevne, brandtekniske egenskaber, fugttekniske egenskaber og bæreevne. Andre forhold af betydning for anvendelse af materialer til varmeisolering af bygninger, som livscyklusvurdering, tilsætningsstoffer og arbejdsmiljø, behandles også. Derefter beskrives 28 forskellige varmeisoleringsmaterialer hver for sig med fokus på egenskaber og typisk anvendelse. Anvisningen beskriver funktionskrav til ydervægge, terrændæk og tag med særligt fokus på, hvad man skal være opmærksom på ved anvendelse af materialer til varmeisolering, og eksempler på udformninger, der lever op til disse krav. Den viser også eksempler på forskellige konstruktioners klimapåvirkning for at illustrere, hvilken betydning valget af materialer har for en given bygningsdel ved en livscyklusvurdering. Afslutningsvis giver anvisningen eksempler på efterisolering af muret etagebyggeri. Anvisningen er rettet mod projekterende og udførende i byggebranchen, professionelle bygherrer, bygningsmyndigheder samt producenter og leverandører af isoleringsmaterialer. Anvisningen kan også anvendes i undervisningsøjemed.

Heat Transfer - Advances in Fundamentals and Applications explores new knowledge in the domain of fundamental and applied advances in heat transfer. This book specifically emphasizes advanced topics of heat transfer. Professionals, researchers, and academics working in various areas of heat transfer will find this a useful reference for finding new solutions to heat transfer problems. The book is organized into two sections on the fundamental advances in heat transfer and advances in applications of heat transfer. Chapters address inverse conduction problems, heat transfer enhancement during internal flows, shell-and-tube heat exchangers, heat transfer mechanisms in petroleum and geothermal wellbores, and other topics in the field.

Un motore diesel monocilindrico a quattro tempi (Kirloskar) è stato testato a pieno carico con il carburante miscelato alla velocità nominale di 1500 giri/min. Come carburante sono stati utilizzati MOME, MOEE e WCME miscelati al diesel in proporzioni del 5%, 10%, 15% e 20% in volume e diesel puro. Le prestazioni del motore (consumo specifico di carburante, efficienza termica al freno e potenza al freno) e le emissioni di scarico (HC, CO, CO2 e NOx) sono state misurate per valutare e calcolare il comportamento del motore diesel alimentato a biodiesel. I risultati mostrano che l'efficienza termica al freno del diesel è maggiore a tutti i carichi, seguita dalle miscele di estere metilico di Mahua e diesel. Sperimentalmente, l'efficienza termica al freno massima e il consumo specifico di carburante minimo sono stati riscontrati per miscele fino al 20% di estere metilico di olio di Mahua a tutti i carichi tra le miscele. Il consumo specifico di carburante è risultato addirittura inferiore a quello del diesel convenzionale per miscele fino al B20. Le emissioni di CO sono risultate inferiori a quelle del diesel, mentre si è registrato un leggero aumento dell'opacità dei fumi e degli NOx. Le riduzioni del consumo specifico di carburante al freno e delle emissioni di CO rendono la miscela di biodiesel B20 un carburante alternativo adatto al motore diesel.

Ein Einzylinder-Viertakt-Dieselmotor (Kirloskar) wurde unter Volllast mit dem gemischten Kraftstoff bei einer Nenndrehzahl von 1500 U/min getestet. Als Kraftstoff wurden MOME, MOEE und WCME in Anteilen von 5, 10, 15 und 20 Volumenprozent mit Diesel und reinem Diesel gemischt. Die Motorleistung (spezifischer Kraftstoffverbrauch, thermischer Bremswirkungsgrad und Bremsleistung) und die Abgasemissionen (HC, CO, CO2 und NOx) wurden gemessen, um das Verhalten des mit Biodiesel betriebenen Dieselmotors zu bewerten und zu berechnen. Die Ergebnisse zeigen, dass der thermische Wirkungsgrad des Dieselmotors bei allen Lasten höher ist, gefolgt von Mischungen aus Mahua-Methylester und Diesel. Experimentell wurden der maximale thermische Wirkungsgrad und der minimale spezifische Kraftstoffverbrauch für Mischungen bis zu 20 % Mahua-Ölmethylester bei allen Lasten ermittelt. Der spezifische Kraftstoffverbrauch war bei Mischungen bis B20 sogar niedriger als der von herkömmlichem Diesel. Die CO-Emissionen waren geringer als bei Diesel, während die Rauchtrübung und die NOx-Emissionen leicht zunahmen. Die Verringerung des spezifischen Kraftstoffverbrauchs und der CO-Emissionen machen die Biodieselmischung B20 zu einem geeigneten alternativen Kraftstoff für Dieselmotoren.

Un moteur diesel monocylindre à quatre temps (Kirloskar) a été testé à pleine charge avec le carburant mélangé à la vitesse nominale de 1500 tr/min. Le MOME, le MOEE et le WCME ont été mélangés au diesel dans des proportions de 5 %, 10 %, 15 % et 20 %, en volume, et du diesel pur a été utilisé comme carburant. Les performances du moteur (consommation spécifique de carburant, rendement thermique au frein et puissance au frein) et les émissions de gaz d'échappement (HC, CO, CO2 et NOx) ont été mesurées afin d'évaluer et de calculer le comportement du moteur diesel fonctionnant au biodiesel. Les résultats montrent que le rendement thermique au frein du diesel est plus élevé à toutes les charges, suivi par les mélanges d'ester méthylique de Mahua et de diesel. Expérimentalement, l'efficacité thermique maximale du frein et la consommation spécifique minimale de carburant ont été trouvées pour des mélanges allant jusqu'à 20 % d'ester méthylique d'huile de Mahua à toutes les charges parmi les mélanges. La consommation spécifique de carburant s'est avérée encore plus faible que celle du diesel conventionnel pour les mélanges allant jusqu'à B20. Les émissions de CO se sont révélées inférieures à celles du diesel, tandis que l'opacité des fumées et les NOx ont légèrement augmenté. Les réductions de la consommation spécifique de carburant au frein et des émissions de CO ont fait du mélange de biodiesel B20 un carburant alternatif approprié pour les moteurs diesel.

Um motor diesel monocilíndrico a quatro tempos (Kirloskar) foi testado a plena carga com o combustível misturado à velocidade nominal de 1500 rpm. Foram utilizados como combustível MOME, MOEE e WCME misturados com gasóleo em proporções de 5%, 10%, 15% e 20%, em volume, e gasóleo puro. O desempenho do motor (consumo específico de combustível, eficiência térmica de travagem e potência de travagem) e as emissões de escape (HC, CO, CO2 e NOx) foram medidos para avaliar e calcular o comportamento do motor diesel a funcionar com biodiesel. Os resultados mostram que a eficiência térmica de travagem do diesel é mais elevada em todas as cargas, seguida das misturas de éster metílico de Mahua e diesel. Experimentalmente, a eficiência térmica máxima do travão e o consumo específico mínimo de combustível foram encontrados para misturas até 20% de éster metílico de óleo de mahua a todas as cargas entre as misturas. Verificou-se que o consumo específico de combustível era ainda mais baixo do que o do gasóleo convencional para misturas até B20. As emissões de CO foram inferiores às do gasóleo, tendo-se registado um ligeiro aumento da opacidade dos fumos e dos NOx. As reduções no consumo específico de combustível na travagem e nas emissões de CO tornaram a mistura de biodiesel B20 um combustível alternativo adequado para o motor diesel.

This book provides a solution to the problem with the energy concept. This problem manifests itself in the fact that physicists clearly diverge regarding the question of what energy is. Some define it but others state that we do not know what it is. Although this is a problem for physicists who need to explain the concept, it is not a problem for physics that can be solved by laboratory means. Penetrating into the origin of the notion of energy, this book offers a clear idea of what was discovered and what was invented to interpret the findings.Following the development of the concept, it provides an explanation of the trends in contemporary textbooks. The author's repetition, in his "History and Philosophy of Physics Laboratory", of Joule¿s famous experiment ¿ the paddle wheel experiment ¿ with a calorimeter as originally used by Joule and with a calorimeter as proposed in textbooks, is presented, yielding new insight into the phenomenon. Thus, science teachers andstudents will benefit from reading the book as well as historians, philosophers, students of the history and philosophy of science, and all who are interested in knowing about what it is that we call energy.

This book focuses on nonextensive statistical mechanics, a current generalization of Boltzmann-Gibbs (BG) statistical mechanics.Conceived nearly 150 years ago by Maxwell, Boltzmann and Gibbs, the BG theory, one of the greatest monuments of contemporary physics, exhibits many impressive successes in physics, chemistry, mathematics, and computational sciences. Presently, several thousands of publications by scientists around the world have been dedicated to its nonextensive generalization. A variety of applications have emerged in complex systems and its mathematical grounding is by now well advanced.Since the first edition release thirteen years ago, there has been a vast amount of new results in the field, all of which have been incorporated in this comprehensive second edition. Heavily revised and updated with new sections and figures, the second edition remains the go-to text on the subject.A pedagogical introduction to the BG theory concepts and their generalizations ¿ nonlinear dynamics, extensivity of the nonadditive entropy, global correlations, generalization of the standard CLT¿s, complex networks, among others ¿ is presented in this book, as well as a selection of paradigmatic applications in various sciences together with diversified experimental verifications of some of its predictions. Introduction to Nonextensive Statistical Mechanics is suitable for students and researchers with an interest in complex systems and statistical physics.

Perovskite Solar Cells: Prospects of Commercialization considers the challenges, technological barriers, and opportunities facing the commercialization of perovskite solar cells.First, the book provides a brief overview of the history of perovskite solar cells in the context of therise of photovoltaics, and an overview of materials systems being considered for these technologies. Then, five main aspects of commercialization are examined, including performance, processability, sustainability, potential applications, and economics. The materials properties, including their merits and drawbacks, are discussed along with their relationship to commercial viability with the aim of identifying gaps for further growth in the area.This book is suitable for materials scientists and engineers in academia and industrial R&D interested.

Geothermal Energy Engineering: Technology Transfer from the Oil and Gas Industry focuses on geothermal energy technology, engineering, field, and operational topics as seen from an oil and gas industry perspective. To accelerate development of an important source of clean energy during the energy transition, proven oil and gas technologies can pivot towards geothermal energy production, for both power generation and direct heat applications. The book's chapters are written by world-renewed subject matter experts who address practical applications optimized in the oil and gas industry that can be adapted to accelerate geothermal energy production. The book progresses from an introduction to geothermal energy, cover types of geothermal and hybrid systems, address geothermal subsurface characterization, exploration, drilling, completion and production, facilities and project management, and includes analysis of technical and economic aspects of geothermal systems, gaps and future opportunities.

Transport and diffusion processes are central in numerous scientific and technical applications. Prominent examples are the temperature distribution in continuous media, the flow of liquids or gases, the dynamics of reaction-diffusion systems, or the concentration distributions in mixtures. The theoretical and numerical description of these systems is based on partial differential equations. The theory of non-equilibrium thermodynamics provides a frame to derive these equations from basic conservation laws and first principles. The first part of the textbook discusses the concept of equilibrium thermodynamics and its generalization to systems in local equilibrium. Thermodynamic fluxes are defined and caused by generalized forces. Finally, linear relations, the Onsager relations, between fluxes and forces allow for a closed description. In this way, conservation equations for mass (continuity), momentum (Euler or Navier-Stokes), and energy (temperature) are derived and solved analytically or numerically for several examples. The second part is based on the kinetic gas theory describing a classical many particle system. At the example of a perfect gas the conservation equations derived phenomenologically in the first part are thereby put on statistical grounds. The textbook addresses advanced Bachelor or Master students of physics, mechanical engineering and applied mathematics.

This book addresses research challenges in the rapidly developing area of nonequilibrium thermodynamics and fluctuation kinetics. This cross-disciplinary field comprises various topics, ranging from fundamental problems of nonequilibrium statistical mechanics and thermodynamics to multiple applications in plasma, fluid mechanics, nonlinear science, systems of dissipative particles, and high-Q resonators. The purpose of this book is to bring together world-leading experts in the above fields to initiate a cross-fertilization among these active research areas. The book is dedicated to and honours the memory of Professor Slava Belyi who passed away unexpectedly on May 20, 2020. He was pioneering the theory of nonequilibrium fluctuations, in particular the application of the Callen-Welton fluctuation-dissipation theorem to nonequilibrium systems and its generalization. This and related problems also feature in the book.

This book is a basic textbook of comprehensive thermal science and energy utilization technologies, which is divided into two parts: Engineering Thermodynamics and Heat Transfer. Engineering Thermodynamics mainly introduces the basic concepts and laws of thermodynamics, thermophysical properties of commonly used working medium, analysis of typical thermal processes and cycles and ways to improve the cycle efficiency. Heat Transfer mainly introduces the basic laws of heat conduction, convection and radiation, together with the solving methods and technical measures to control the heat transfer process, and design and check methods for heat exchangers. This book absorbs the experience and advantages of similar textbooks, enriches the discussion of basic concepts and laws, and expands the scope of knowledge of thermal engineering. Whether the readers are students embarking on their academic journey or seasoned engineers seeking to enhance their understanding of thermal phenomena, "Thermal Engineering: Engineering Thermodynamics and Heat Transfer" is an indispensable resource that bridges theory with practice, offering invaluable insights into the complexities of thermal systems and their relevance to modern engineering challenges.

Für alle, die fasziniert vom Fliegen sind und ein tieferes Verständnis dafür entwickeln wollen, wie Vögel und Modellflugzeuge ihre Kreise in der Luft ziehen. Anschaulich und unterhaltsam führt der Autor in die komplexen Sachverhalte von Wirbel, Zirkulation und Auftrieb ein. Verständlich und begreifbar durch zahlreiche Diagramme und Videos. Es gelingt dem Autor die dem dynamischen Auftrieb zugrunde liegenden Gesetzmäßigkeiten besonders anschaulich darzustellen.

The thesis presents a systematic study of the Mpemba effect in a colloidal system with a micron-sized particle diffusing in a water bath. While the Mpemba effect, where a system's thermal relaxation time is a non-monotonic function of the initial temperature, has been observed in water since Aristotle's era, the underlying mechanism of the effect is still unknown. Recent studies indicate that the effect is not limited to water and has been studied both experimentally and numerically in a wide variety of systems. By carefully designing a double-well potential using feedback-based optical tweezers, the author demonstrates that an initially hot system can sometimes cool faster than an initially warm system. The author also presents the first observation in any system of another counterintuitive effect-the inverse Mpemba effect-where the colder of the two samples reaches the thermal equilibrium at a hot temperature first. The results for both the observations agree with theoretical predictions based on the Fokker-Planck equation. The experiments reveal that, for carefully chosen conditions, a strong version of both of the effects are observed where a system can relax to the bath temperature exponentially faster than under typical conditions.

"Introducing the state-of-the-art of hypervelocity shock tunnels, this complete reference features a variety of drivers and step-by-step introductions to their theories, physics, methods and testing. This book enables researchers and engineers in aerospace to design and improve wind tunnels that simulate flow qualities of real hypersonic flyers"--

This book gives an insight into the current developments in the field of continuum mechanics. Twenty-five researchers present new theoretical concepts, e.g., better inclusion of the microstructure in the models describing material behavior. At the same time, there are also more applications for the theories in engineering practice.In addition to new theoretical approaches in continuum mechanics and applications, the book puts an emphasis on discussing multi-physics problems.

Die phänomenologische Thermodynamik ist von wenigen grundlegenden Observablen, Konzepten, und Zusammenhängen bestimmt, die nicht einfach zu vermitteln sind, besonders dann, wenn die notwendige mathematische Vorstellung und Fähigkeit der Studierenden an Grenzen stößt. Das vorliegende Lehr- und Übungsbuch "Chemische Thermodynamik" vermittelt Studierenden im Haupt- und Nebenfach Chemie anschaulich polytrope Zustandsänderungen, Reaktions- und Phasengleichgewichte, Oberflächen und Grenzflächen sowie Verfahren und Vergleich von herkömmlicher und moderner Energiegewinnung und Bioenergetik. Ideal zur Prüfungsvorbereitung sind die rund 500 explizit gelösten Fragen und Aufgaben, u.a. zu idealen und realen Gasen, zur Bioenergetik etc., und der lerndidaktisch förderliche Anspruch auf Parallelität von prägnanter Fassung der Theorie und extensiver fächerintegrierender Übung. Neu in der 4., umfassend überarbeiteten und ergänzten Auflage: - Zusätzliche Kapitel zu schadstofffreien Emissionen, thermischer Analyse und Umwandlungsketten von grünem Wasserstoff als klimaneutraler Brennstoff der deutschen Energiewende. - Zusätzliche Übungsaufgaben und Lösungen. - Optimal zur Prüfungsvorbereitung und darüber hinaus.