Maschinenbau Allgemein

Die vorliegende Arbeit beschäftigt sich mit der Entwicklung eines makroskopischen Kontinuumsmodells zur Untersuchung des Einflusses des flexoelektrischen Effekts auf mikrostrukturelle Domänenumklappprozesse in ferroelektrischen Funktionskeramiken. Dabei ist von Interesse, ob in Piezokeramiken durch direkte Flexoelektrizität ein Polungsprozess in Gang gesetzt werden kann und ob durch indirekte Flexoelektrizität eine Verbesserung der aktorischen Eigenschaften eines IDE-Wafers möglich ist. The present work deals with the development of a macroscopic continuum model to investigate the influence of the flexoelectric effect on microstructural domain switching processes in ferroelectric ceramics. It is of interest whether direct flexoelectricity can initiate a poling process in piezoceramics and if indirect flexoelectricity can improve the actuator performance of an IDE wafer.

We investigate deep material networks (DMN). We lay the mathematical foundation of DMNs and present a novel DMN formulation, which is characterized by a reduced number of degrees of freedom. We present a efficient solution technique for nonlinear DMNs to accelerate complex two-scale simulations with minimal computational effort. A new interpolation technique is presented enabling the consideration of fluctuating microstructure characteristics in macroscopic simulations.

In practical applications related to machining a workpiece, the resonance frequency is always an important parameter and must be taken into account. The removal of material is inherent to the entire machining process, so variations in the mass of the workpiece exist. In addition, as part geometry changes, variations in stiffness in a given direction are also present. These two parameters determine the natural frequency of an object and, together with the damping factor, also determine the resonance frequency. In a milling process with tool rotation at constant speed, excitation values close to the resonance frequency of the workpiece (which is always changing as material is removed) can be reached at different times. This condition should be avoided, since a workpiece excited at its resonance frequency tends to reach large vibration amplitudes, which can be catastrophic for the process, resulting in a poor surface finish and, in more critical situations, catastrophic machine and tool failures. In order to avoid excitations under these conditions, numerical simulation is a valid process for predicting the frequencies of vibration.

Digitalisierung und Automatisierung bemächtigen sich schrittweise der Mobilität als Daseinsbedürfnis und des Verkehrssystems als leistende Infrastruktur. Die Ausrüstung der Fahrzeuge schafft veränderte Bedingungen für die Ausübung der Mobilität für alle verkehrsteilnehmenden Gruppen, wenn autonome Bewegungen von Fahrzeugen im öffentlichen Räumen angestrebt werden. Daher bedarf es der Stärkung der verkehrstheoretischen Grundlagen zur Meisterung der technologischen Herausforderungen als Ergänzung zur fahrzeugzentrierten Funktions- und Nutzenbetrachtung der Automobil-Branche. Hierzu sind die Einbettungen dieser Technologien nach Maßstäben herauszuarbeiten, die über den operativen Wirkungsbereich der im Kraftfahrzeug installierten Funktionalitäten hinausreichen. Damit werden verkehrspolitische Regulative der breiten Anwendung ebenso berührt wie verkehrsplanerische Detaillösungen vor Ort. Dadurch erweitert sich der Kreis der zu beteiligenden Fachdisziplinen erheblich. Nicht zuletzt sinddie von den technologischen Neuerungen betroffenen Mobilitätsgruppen anzusprechen. Die Testung der Einsatzfähigkeit der Automat-Funktionen und ihrer Systemintegration im Fahrzeug ist Kernaufgabe des Automotiv-Sektors, jedoch ist die Prüfung der Verkehrstauglichkeit bei der Benutzung öffentlicher Straßenräume eine gemeinsame Aufgabe im Dialog mit den Verkehrsinfrastrukturbetreibern und den Vertretungen der betroffenen Gruppen unter den Verkehrsteilnehmer*innen. Die solcherart adressierten Akteurskreise im Mobilitätssystem werden Anforderungen an die Operabilität und Sicherheit formulieren, um eine klaglose Integration in das alltägliche Verkehrsgeschehen im Straßennetz sicherzustellen. Schließlich gilt es, die relevanten Aspekte im Diskurs zu benennen und die Aufgabenstellungen in einem schrittweisen Zulassungspfade anzuordnen.

Sredi faktorow, wliqüschih na äffektiwnost' fotoälektricheskih panelej, - peregrew. Pri powyshenii temperatury na 1°C äffektiwnost' fotoälektricheskoj paneli padaet na 1%. Cel'ü dannogo issledowaniq qwlqetsq razrabotka nowoj tehnologii dlq uluchsheniq äffektiwnosti fotoälektricheskih (PV) panelej. Dlq uluchsheniq äffektiwnosti fotoälektricheskih panelej byli predlozheny dwe tehnologii. Perwaq tehnologiq zaklüchaetsq w pokrytii paneli maslom dlq uluchsheniq pogloschaüschej sposobnosti powerhnosti paneli. Bylo ustanowleno, chto pokrytie fotoälektricheskoj paneli sloem masla Labovac tolschinoj 10 mm powyshaet äffektiwnost' fotoälektricheskoj paneli bolee chem na 6%. Vtoroj metod zaklüchaetsq w ispol'zowanii passiwnogo ohlazhdeniq. Process ohlazhdeniq byl usilen putem sozdaniq estestwennyh konwekcionnyh tokow. V monokristallicheskoj paneli byli proswerleny otwerstiq dlq togo, chtoby gorqchij wozduh s nizkoj plotnost'ü pod fotoälektricheskoj panel'ü podnimalsq cherez äti otwerstiq. Bylo obnaruzheno, chto srednqq raznica temperatur mezhdu panel'ü s otwerstiqmi i drugoj panel'ü bez otwerstij sostawlqet 5°C Dal'nejshie parametry byli izucheny s pomosch'ü CFD. Bylo obnaruzheno, chto temperatura fotoälektricheskoj paneli snizhaetsq po mere uwelicheniq kolichestwa otwerstij. Krome togo, raspolozhenie otwerstij wliqet na temperaturu fotoälektricheskih panelej.

This work proposes a new numerical approach for analyzing the behavior of fiber-reinforced materials, which have gained popularity in various applications. The approach combines theories and methods to model the fracture behavior of the polymeric matrix and the embedded fibers separately, and includes a modified plasticity model that considers the temperature-dependent growth of voids. Tests are conducted to explore different types and sequences of failure in long fiber-reinforced polymers.

This edited book provides an in-depth overview of carbon dioxide (CO2) transformations to sustainable power technologies. It also discusses the wide scope of issues in engineering avenues, key designs, device fabrication, characterizations, various types of conversions and related topics. It includes studies focusing on the applications in catalysis, energy conversion and conversion technologies, etc. This is a unique reference guide, and one of the detailed works is on this technology. The book is the result of commitments by leading researchers from various backgrounds and expertise. The book is well structured and is an essential resource for scientists, undergraduate, postgraduate students, faculty, R&D professionals, energy chemists and industrial experts.

In dieser Arbeit werden Bruchbildungs-, Kristallisations- und Kristallauflösungsprozesse in unterirdischen hydrothermalen Umgebungen auf Mikroebene numerisch untersucht. Für die Abbildung dieser Prozesse werden Phasenfeld-Modelle vorgestellt. Es werden Bildungsprozesse von Mineraladern in Kalksteinen und in quarzreichen Mikrostrukturen und Auflösungsprozesse von verschiedenen Mineralen modelliert, wobei verschiedene Einflussfaktoren auf die sich bildenden Kristallstrukturen untersucht werden. This work focuses on the numerical investigation of fracture formation, crystallization, and crystal dissolution processes in subsurface hydrothermal environments on microscale. Phase-field models are presented and applied to these processes. The formation of mineral veins in limestones and in quartz-rich microstructures are modeled to investigate different factors which influence the evolving crystal structure. Moreover, crystal dissolution processes of different minerals are modeled.

This book opens up a critical dimension to the field of industrial ecology. The book discusses the post COVID-19 trends in the field of industrial ecology and evolving practices adopted by firms for betterment of environment and society. The authors identify valuable lessons to be learned and present conceptual frameworks to guide future industrial ecology applications. Transforming industrial systems into closed-loop industrial ecosystems dramatically reduces the negative impact of industrial activities on the environment. Therefore, this book is important not only for operation management scholars but also those who are interested in ensuring an environmentally sustainable future.

Sheet Molding Compounds (SMC) are discontinuous fiber reinforced composites that are widely applied due to their ability to realize composite parts with long fibers at low cost. A novel Direct Bundle Simulation (DBS) method is proposed in this work to enable a direct simulation at component scale utilizing the observation that fiber bundles often remain in a bundled configuration during SMC compression molding.

Die nicht-konventionelle Bearbeitung spielt heutzutage eine wesentliche Rolle bei der Bearbeitung von Metallen. Bei der Zerspanung ist das Bearbeitungswerkzeug wichtig, wie z.B. bei der Lattenbearbeitung das Einpunktschneiden, so dass bei der magnetisch-abrasiven Bearbeitung die magnetischen Schleifmittel der entscheidende Schlüssel sind, da die gesamte Bearbeitung von der Leistung der magnetischen Schleifmittel abhängig ist. In diesem Buch wird die Herstellung von magnetischen Schleifmitteln durch einen Sinterprozess beschrieben.

Reliability is defined as the ability of a system or component to function under specified settings for a stated period of time. It often plays a crucial role in the cost-effectiveness of a system. The sub-discipline of systems engineering that focuses on the capacity of equipment to function without failure is known as system reliability engineering. It deals with the prediction, prevention and management of high levels of engineering uncertainty and failure risks. Availability, testability, maintainability and maintenance fall under the umbrella of reliability engineering. It focuses on costs of failure resulting from system downtime, cost of spares, repair equipment, personnel and cost of warranty claims. Different approaches, evaluations, methodologies and advanced studies on system reliability have been included in this book. It elucidates the concepts and innovative models around prospective developments with respect to this field. As this field is emerging at a rapid pace, the contents of this book will help the readers understand the modern concepts and applications of the subject.

The impact of two non-uniform elastic rods is considered and a recursive method was developed that solves the inverse problem: Find the location-dependent impedance function of the impacting rod that generates a prescribed impact force. The developed method delivers exact solutions in closed-form. Moreover, a condition is derived which states if a physically meaningful solution exists. Finally, the underlying 1D model has been validated experimentally.

Im Rahmen dieser Arbeit wird der Erstarrungsprozess der Hochtemperaturwerkstoffe mit der Phasenfeldmethode untersucht. Die vorliegende Arbeit umfasst eine vollständige Untersuchungskette, die sich von der Modellierung der Materialsysteme, über die Durchführung repräsentativer Phasenfeldsimulationen, bis hin zur Analyse der sich entwickelnden Mikrostrukturen erstreckt. In this work, the solidification process of the high-temperature materials NiAl-34Cr und Nb-Si is investigated with the phase-field method. This work includes an entire investigation chain from the modeling of the material systems to the conduction of representative phase-field simulations, and finally to the analyzation of the resulting microstructures.

Für die Entwicklung neuer LKW ist es von Interesse, den subjektiv wahrgenommenen Fahrkomfort möglichst frühzeitig vor dem Bau realer Prototypen beurteilen und abstimmen zu können. Dazu sind objektive, messbare Kennwerte notwendig, welche den Fahrkomfort beschreiben und mit deren Hilfe dieser aus Messungen oder Simulationsergebnissen vorhergesagt werden kann. Im Rahmen der vorliegenden Arbeit werden entsprechende Kennwerte für drei ausgewählte komfortrelevante Schwingungsphänomene erarbeitet. A time efficient development process of new trucks includes an early development of ride comfort before real prototypes exist. Therefore it is necessary to determine objective and measurable characteristic values to predict the subjectively percepted ride comfort from measurement or simulation results. The aim of this work is the determination of objective characteristic values for three selected vibration phenomena and the prediction of their subjective evaluations.

Im Rahmen dieser Arbeit wurden Fahrhinweise entwickelt, die den Fahrer dabei unterstützen sollen, seine Fahraufgabe möglichst energieeffizient zu meistern. Bei den Fahrhinweisen handelt es sich um ein Fahrerassistenzsystem. Die Fahrhinweise wurden implementiert und in einer Probandenstudie auf ihrer Wirkungsweise überprüft. In this work, the author developed driver advices, that help the driver to perform his driving task in an efficient way. This advices are classified as a driver assistance system. They have been implemented and their influence on the driver has been investigated during a case study.

In der Erdölindustrie bezieht sich der Begriff "Heben" auf die Entnahme von Kohlenwasserstoffen aus dem Untergrund. Dieses Anheben von Erdölflüssigkeiten kann auf natürliche oder künstliche Weise erfolgen. Es gibt verschiedene Technologien und Techniken, die diesen Fluss an die Oberfläche fördern. Darüber hinaus ermöglicht die Fähigkeit, das Verhalten der Lagerstätten vorherzusagen, die Festlegung von Strategien zur Optimierung dieser Produktion. Das Buch "Ein Überblick über die Kohlenwasserstoffproduktion: Von der natürlichen zur künstlichen Erhebung" befasst sich in seinen Kapiteln mit der natürlichen und künstlichen Förderung von Kohlenwasserstoffen und behandelt spezifische Themen wie: die Mechanismen der Förderung, Reservenschätzungen, Modellierung und numerische Simulation von Lagerstätten, konventionelle künstliche Fördermethoden und Onshore- und Offshore-Ölförderanlagen.

In questo libro la gobba (o dosso) è un ostacolo di forma comune, che crea un gradiente di pressione avverso, e quindi, c'è una possibilità di separazione a valle di una gobba. Questa separazione porta ad un aumento del coefficiente di resistenza (Cd), che è indesiderabile. Questo corpo/forma ha guadagnato importanza negli ultimi tempi perché ci sono molti fenomeni di flusso in cui la maggior parte della perdita si verifica a causa della separazione su qualsiasi corpo o elemento sporgente su qualsiasi pianale. a) Include la revisione della letteratura, che consiste di due sottosezioni che si concentrano su gobba e generatori di vortici descrive la metodologia sperimentale compreso il flusso. b) Configurazione, strumentazione e procedura sperimentale con elaborazione dei dati per la presente indagine è la sezione risultati e discussione, c) Che dà dettagli dei risultati ottenuti nel corso di questo studio? Conclude la ricerca, e suggerisce i possibili progressi nel lavoro attuale per studi futuri.d) Quindi la gobba può essere trattata come un corpo di geometrie oblique e viene indagata nel presente per analizzare l'effetto del generatore di vortici per controllare il flusso turbolento. e) L'obiettivo del lavoro è quello di trovare sperimentalmente la posizione ottimale.

You can thrive and excel when you’re working remotely, if you adopt the mindset, habits and tech tools of professionals who are even more productive outside the office: Learn to think like a “business of one,” and that entrepreneurial mindset will transform your experience of remote work.Remote work can be satisfying and productive—once you craft a strategy that taps into the unique advantages of working from home. After a year in which many of us plunged into remote work overnight, we finally have a chance to make thoughtful choices about how to combine remote and office work, and how to make the most of our days at home.Remote, Inc. gives you the strategies and tools you need to make remote work a valuable part of your renewed working life. Learn how to...- Gain control over how and when you work by focusing on objectives, not the 9-to-5 workday.- Wow your managers by treating them like valued clients.- Beat information overload by prioritizing important emails and messages.- Make online meetings purposeful, focused and engaging.- Build great relationships with your colleagues—whether at the next desk, or another city.- Find a balance between work from home, and life at home.- Make a remote work plan that lets you get the best from time at the office—and the best of home.Remote, Inc. takes you inside the mindset and habits of people who flourish while working outside the office some or all of the time: people who function like a “business of one.” That’s how productivity experts Robert C. Pozen and Alexandra Samuel describe the mindset that lets people thrive when they’re working remotely, whether full-time or in combination with time at the office. You can follow their lead by embracing the work habits and independence of a small business owner—while also tapping into the benefits of collegiality and online collaboration.

L'obiettivo principale di questo lavoro è quello di studiare l'effetto degli additivi sul comportamento in trazione e flessione del tessuto in fibra di Kevlar a livello di laminato per esplorare un materiale alternativo per la pelle del corpo esterno di applicazioni e macchine aerospaziali. Questo lavoro sperimentale indaga l'effetto della concentrazione di grafene nella resina epossidica sulle proprietà di trazione e di flessione del laminato in fibra di Kevlar di 4 mm di spessore. Il laminato è stato preparato utilizzando il metodo di laminazione a mano e su di esso è stato condotto un test. Diversi valori di proprietà di trazione e di flessione ottenuti dalla sperimentazione sono stati confrontati per i compositi laminati in fibra di Kevlar di tre diverse concentrazioni, fabbricati aggiungendo la polvere di grafene al bagno di resina.L'effetto della variazione di peso della concentrazione di grafene (5%, 6% e 7%) sul materiale preparato.Le proprietà meccaniche possono essere studiate con una macchina di prova universale (UTM) secondo gli standard ASTM. L'indagine analitica dei compositi può essere fatta nel software Autodesk fusion 360 ei risultati sperimentali sono stati tabulati e caratterizzati

We are pleased to present this book, which is a reprint of articles from the Special Issue entitled "Extraction Strategies to Recover Bioactive Compounds, Incorporation into Food, and Health Benefits" published online in the open access journal Foods (ISSN 2304-8158) from 2019 to 2020 (available at: https://www.mdpi.com/journal/foods/special_issues/extraction). Firstly, this book gathers studies addressing several strategies applied to obtain bioactive products and extracts, not only from food matrices but also from agri-food byproducts, which can serve as new natural additives, nutraceuticals, and functional ingredients for pharmaceutical, cosmetics, and food industries. In particular, free and bound phenolic compounds are explored in buckwheat, sesame, and olive leafy byproducts. Overall, these studies outline new valorization methods and offer new opportunities for alternative practices in the agro-industrial sector that help to migrate toward a circular bioeconomy model. This book also presents studies that predict bioactive components in fruits through mathematical tools and support the formulation of a novel beverage rich in resveratrol, a phenolic compound whose bioactivity is well recognized.

Carbon materials are one of the most fascinating materials because of their unique properties and potential use in several applications. They can be obtained from residues or by using advanced synthesis technologies like chemical vapor deposition. The carbon family is very broad, ranging from classical activated carbons to more advanced species such as carbon nanotubes and graphene. The surface chemistry is one of the most interesting aspects of this broad family of materials, which allows the incorporation of different types of chemical functionalities or heteroatoms on the carbon surface, such as O, N, B, S, or P, which can modify the acid–base character, hydrophobicity/hydrophilicity, or the electronic properties of these materials and, thus, determine the final application. This book represents a collection of original research articles and communications focused on the synthesis, properties, and applications of heteroatom-doped functional carbon materials.