1,982 research outputs found
Proceedings of SIRM 2023 - The 15th European Conference on Rotordynamics
It was our great honor and pleasure to host the SIRM Conference after 2003 and 2011 for the third time in Darmstadt. Rotordynamics covers a huge variety of different applications and challenges which are all in the scope of this conference. The conference was opened with a keynote lecture given by Rainer Nordmann, one of the three founders of SIRM “Schwingungen in rotierenden Maschinen”. In total 53 papers passed our strict review process and were presented. This impressively shows that rotordynamics is relevant as ever. These contributions cover a very wide spectrum of session topics: fluid bearings and seals; air foil bearings; magnetic bearings; rotor blade interaction; rotor fluid interactions; unbalance and balancing; vibrations in turbomachines; vibration control; instability; electrical machines; monitoring, identification and diagnosis; advanced numerical tools and nonlinearities as well as general rotordynamics. The international character of the conference has been significantly enhanced by the Scientific Board since the 14th SIRM resulting on one hand in an expanded Scientific Committee which meanwhile consists of 31 members from 13 different European countries and on the other hand in the new name “European Conference on Rotordynamics”. This new international profile has also been
emphasized by participants of the 15th SIRM coming from 17 different countries out of three continents. We experienced a vital discussion and dialogue between industry and academia at the conference where roughly one third of the papers were presented by industry and two thirds by academia being an excellent basis to follow a bidirectional transfer what we call xchange at Technical University of Darmstadt. At this point we also want to give our special thanks to the eleven industry sponsors for their great support of the conference. On behalf of the Darmstadt Local Committee I welcome you to read the papers of the 15th SIRM giving you further insight into the topics and presentations
Cardiovascular health: from cardiomyocyte electrostimulation to miRNA detection
Current methods of cell culture where electrical stimulation is applied during culture require a wired connection to a power supply to generate an electric field with which to stimulate the cells. This method is intrusive in a lab setting and does not conveniently allow for traditional cell culture techniques during stimulation, hence it is frequently omitted from cell culture protocols. The aim of this work is to demonstrate a novel method of electrical stimulation of cardiomyocytes using wireless bipolar electrochemical techniques. The work describes the design and characterisation of a wireless bipolar electrode and wireless bipolar electrochemical cell to facilitate wireless bipolar electrostimulation. By using a wireless connection more versatile experiments can be conducted on cells in culture while mitigating the contamination risk of a traditional wired stimulation platform.
Using a polypyrrole based conducting film doped with fibronectin molecules to facilitate the adherence and growth of cardiomyocytes on the bipolar electrode surface. Cell culture on a conductive film opens the possibility of future applications in electroceuticals by providing a wireless platform to deliver and electric field to cells in culture.
Demonstrating cell culture on conductive polymer with the application of electric fields allows for the study of healthy and disease cell populations in the presence of electrical stimuli. Biomarker monitoring during this work is important to characterise and understand the impact of stimuli on the cells in culture. As such, an electrochemical miRNA biosensor was also explored in this work. The assay was based on the detection of miRNA through hydrogen peroxide degradation. The assay was built of screen-printed electrodes as a method to characterise cell cultures. The ability to monitor biomarkers both in vitro and in vivo is important in generating an understanding of disease models and in the development of point-of-care testing capabilities
Selected problems of materials science. Vol. 2. Nano-dielectrics metals in electronics. Mеtamaterials. Multiferroics. Nano-magnetics
The textbook examines physical foundations and practical application of current electronics materials. Modern theories are presented, more important experimental data and specifications of basic materials necessary for practical application are given. Contemporary research in the field of microelectronics and nanophysics is taken into account, while special attention is paid to the influence of the internal structure on the physical properties of materials and the prospects for their use. English-language lectures and other classes on the subject of the book are held at Igor Sikorsky Kyiv Polytechnic Institute at the departments of “Applied Physics” and “Microelectronics” on the subject of materials science, which is necessary for students of higher educational institutions when performing scientific works.
For master’s degree applicants in specialty 105 “Applied physics and nanomaterials”.Розглянуто фізичні основи та практичне застосування актуальних матеріалів електроніки. Подано сучасні теорії, наведено найважливіші експериментальні дані та специфікації основних матеріалів, які потрібні для практичного застосування. Враховано сучасні дослідження у галузі мікроелектроніки та нанофізики, при цьому особливу увагу приділено впливу внутрішньої структури на фізичні властивості матеріалів і на перспективи їх використання. Англомовні лекції та інші види занять за тематикою книги проводяться в КПІ ім. Ігоря Сікорського на кафедрах «Прикладна фізика» та «Мікро-електроніка» за напрямом матеріалознавство, що необхідно студентам вищих навчальних закладів при виконанні наукових робіт.
Для здобувачів магістратури за спеціальністю 105 «Прикладна фізика та наноматеріали»
Structural optimization in steel structures, algorithms and applications
L'abstract è presente nell'allegato / the abstract is in the attachmen
Towards light-driven catalysis in block copolymer micelles
Im Rahmen dieser Arbeit wurden die Synthese, Charakterisierung und Untersuchungen polymerbasierter, sogenannter „weicher“ Materie als Matrizen für lichtgetriebene Redoxreaktionen behandelt. Der erste Teil dieser Arbeit umfasste die Präparation von pH-responsiven Mizellen in Wasser auf Grundlage von maßgeschneiderten, amphiphilen Blockcopolymeren, wobei unter anderem die im hydrophilen Teil vorhandenen Liganden zur Anbindung von Übergangsmetallkomplexen genutzt wurden. Auf diese Weise konnten (photo)katalytisch aktive Zentren innerhalb der pH-sensitiven Corona der Mizellen integriert werden. Mit diesem Ansatz war es möglich, mittels Konformationsänderungen der Corona der Mizellen deren Aktivität in verschiedenen, photokatalytischen Systemen experimentell zu kontrollieren und mit theoretischen Modellen zu analysieren. Der zweite Teil dieser Abhandlung widmete sich der Verwendung eines alternativen, polaren und funktionalisierbaren Monomer zum Aufbau analoger Blockcopolymerarchitekturen in methanolischen Lösungen sowie einer Anwendung in photokatalytischen Prozessen. Es ließen sich auf der chemischen Struktur basierende Indizien einer weit über die bloße mechanische Integration hinausreichende Funktion der Matrix feststellen. Dies wurde auch durch eine gesamtheitliche Betrachtung beider Systeme herausgearbeitet. Der dritte Teil dieser Arbeit fokussierte sich auf photokatalytische Modellsysteme, um Fallstudien zur Reproduzierbarkeit in einem modularen Photoreaktor durchzuführen. Ein weiteres Modellsystem wurde für eine didaktische Anwendung zugänglich gemacht. Mit dieser Arbeit war es möglich einen substanziellen Beitrag zur weichen Materie-vermittelten lichtgetriebenen Katalyse zu leisten. Dies geschah sowohl durch die Präsentation von Konzepten zur Integration derartiger Systeme in weicher Materie als auch der resultierenden Möglichkeit stoffliche und energetische Mechanismen in solchen Matrizen nachzuvollziehen
Design and Development of a Multi-Frequency System for Microwave Heating
[ES] La utilización de sistemas de microondas para aplicaciones de calentamiento está muy extendida, principalmente por su uso en el calentamiento doméstico. El volumen de ventas del horno de microondas doméstico refleja un dato curioso: es el electrodoméstico más vendido en el mundo cada año. Por ello, el coste de producción del elemento principal, el magnetrón, presenta unos márgenes de beneficio imbatibles. Sin embargo, los avances en la fabricación de generadores de RF de alta potencia de estado sólido han puesto de manifiesto no solo las limitaciones de los sistemas basados en magnetrón sino también las grandes ventajas de la tecnología de transistores.
Actualmente, los amplificadores de potencia de estado sólido han alcanzado una madurez suficiente como para competir en eficiencia, coste y calidad de la onda generada con el magnetrón. Las principales ventajas de los transistores son un reducido tamaño, tensiones de alimentación bajas, un espectro puro en frecuencia, un mayor tiempo de vida y el control digital directo. Los sistemas de microondas con esta tecnología están siendo introducidos en el mercado desde hace diez años, aunque las aplicaciones reales que los utilizan son escasas. La principal razón es la falta de diseños de aplicadores específicos para sacar el máximo provecho a las fuentes de estado sólido. , por tanto, es éste el objetivo de la tesis doctoral.
Los sistemas S2MH (Solid-State Microwave Heating) se presentan en esta disertación doctoral como una alternativa que ofrece un calentamiento mejorado. La posibilidad de seleccionar la frecuencia exacta, ajustar la potencia de salida y realizar barridos de fase de forma coherente con múltiples iluminadores proporcionan al sistema un control preciso del proceso de calentamiento. El resultado directo de éste es un calentamiento homogéneo y el uso de la tecnología de microondas en procesos de alto valor añadido y fuerte dependencia con la temperatura.
Esta tesis doctoral presenta el trabajo realizado en el diseño y fabricación de dos sistemas S2MH: el primero es un horno estático versátil para diferentes procesos químicos, y el segundo un horno de transporte para el secado de almendras. Estos dos sistemas están formados por el SSMGS (Solid-State Microwave Generator System), que incluye cuatro amplificadores de estado sólido (SSPA) con una generación de la onda coherente, y el aplicador.
Para el diseño del SSMGS se han tenido en cuenta los requisitos de potencia y frecuencia de cada aplicación. Se ha utilizado un SSMGS con cuatro PA de 250 W a 2,450 MHz para el horno de aplicaciones químicas, mientras que el secado de almendras necesita cuatro PA de 500 W a 915 MHz. Los dos sistemas de generación de microondas permiten un control individual o combinado de los parámetros de los cuatro módulos amplificadores, i.e., potencia, frecuencia y fase.
Todo el proceso de diseño ha sido llevado a cabo mediante modelado multi-físico, poniendo un especial cuidado en las propiedades termofísicas y dieléctricas de los alimentos y soluciones acuosas que tienen una importante dependencia con la temperatura. El comportamiento completo del sistema aplicador se ha estudiado con estas herramientas. Tras la fabricación de los dos prototipos o pruebas de concepto (PoC), los resultados obtenidos presentan un comportamiento similar al modelo y muestran, además, prometedoras mejoras frente a los sistemas actuales. El sistema de aplicaciones químicas presenta mejoras en la distribución de campo, independientemente de la aplicación y la carga. Y el sistema de secado de almendras proporciona un mayor control sobre el proceso evitando la pérdida de material por sobrecalentamiento.[CA] La utilització de sistemes de microones en aplicacions d'escalfament està molt estesa, principalment pel seu us en escalfament domèstic. El volum de ventes del forn de microones domèstic reflexa una informació curiosa: es l'electrodomèstic més venut anualment al món. Per això, el cost de producció del seu element principal, el magnetró, presenta uns marges de benefici imbatibles. No obstant això, els avanços en la fabricació de generadors de RF d'alta potencia d'estat sòlid han posat de manifest tant les limitacions dels sistemes basats en magnetró, com els grans avantatges de la tecnologia de transistors.
Actualment, els amplificadors de potència d'estat sòlid son el suficientment madurs com per competir en eficiència, cost i qualitat de l'ona generada amb el magnetró. Els principals avantatges dels transistors son les dimensions reduïdes, tensions d'alimentació baixes, un espectre pur en freqüència, major temps de vida i el control digital directe. Els sistemes de microones amb aquesta tecnologia estan sent introduïts al mercat des de fa deu anys, malgrat les aplicacions reals son escasses. El principal motiu és la falta de dissenys de aplicadors específics per obtindré el màxim profit de les fonts d'estat sòlid. , por tanto, es éste el objetivo de la tesis doctoral.
Els sistemes S2MH es presenten en esta dissertació doctoral com una alternativa que ofereix un escalfament millorat. La possibilitat de seleccionar la freqüència exacta, ajustar la potència d'eixida i realitzar un rastreig de fase de forma coherent amb molts il·luminadors proporcionen al sistema un control precís del procés d'escalfament. El resultat directe d'aquest es un escalfament homogeni i el us de la tecnologia de microones en processos d'alt valor afegit i alta sensibilitat a la temperatura.
Aquesta dissertació doctoral presenta el treball realitzat en el disseny i fabricació de dos sistemes S2MH: el primer és un forn estàtic i versàtil per a diferent processos químics, i el segon es tracta d'un forn de transport per l'assecatge d'ametles. Tots dos sistemes estan formats pel SSMGS, que inclou quatre amplificadors d'estat sòlid (SSPA) amb generació coherent de l'ona, i l'aplicador.
Per al disseny del SSMGS s'han tingut en compte els requisits de potència i freqüència de cada aplicació. S'ha utilitzat un SSMGS amb quatre PA de 250 W a 2,450 MHz per al forn d'aplicacions químiques, mentre que per al d'assecat d'ametla es necessita quatre PA de 500 W a 915 MHz. Ambdós sistemes de generació de microones permeten un control individual o combinat dels paràmetres dels quatre mòduls amplificadors, i.e., potència, freqüència i fase.
Tot el procés de disseny ha sigut realitzat amb l'ajuda del modelat multi-físic, prestant una especial atenció a les propietats termofísiques i dielèctriques dels aliments i solucions aquoses, que tenen una important dependència de la temperatura. El comportament complet del sistema aplicador ha sigut estudiat amb estes ferramentes digitals. Després de la fabricació dels dos prototips o proves de concepte (PoC), els resultats obtinguts presenten un comportament similar al model i, a més a més, mostren millores prometedores front als sistemes actuals. El sistema d'aplicacions químiques presenta millores en la distribució de camp, independentment de l'aplicació i la càrrega. I el sistema d'assecatge d'ametlles proporciona un major control sobre el procés, evitant la pèrdua de material per sobreescalfament.[EN] Microwave systems are widely used for heating applications, mainly domestic food heating. The microwave oven sales figures place it as the first domestic appliance, giving its core element, the magnetron, an unbeatable production cost margin. However, recent improvements in RF high-power generator manufacturing have pointed out not only the limitations of these systems based on the magnetron but also the main benefits of the transistors technology.
Nowadays, solid-state power amplifiers are mature enough to compete in efficiency, cost and quality with the magnetron. Transistors' main benefits are their reduced size, low operation voltages, pure frequency spectrum, lifetime, and straightforward digital control. Microwave systems based on solid-state power amplifiers have been recently introduced, although the real applications making use of them are rare. The main issue is the lack of applicator designs for specific solid-state sources that fully exploit the mentioned advantages; therefore, this is the main objective of the present PhD thesis.
Solid-State Microwave Heating (S2MH) systems are presented in this PhD dissertation as an alternative that offers enhanced heating. Fine frequency selection, adjustable output power and coherent phase sweep in multiple outputs provide the system with accurate control over the heating process. The direct outcome of this control is the production of homogeneous heating and the application of microwave technology into high-added-value temperature-sensitive processes.
The complete design and manufacture of two S2MH systems have been carried out and presented in this PhD thesis. The two designed systems are a multi-process chemical lab batch oven and an almond drying conveyorized oven. These two systems are composed of the Solid-State Microwave Generator System (SSMGS), consisting of four Solid-State Power Amplifiers (SSPA) with coherent wave generation, and the applicator.
The design of the SSMGS has been carried out according to the power and frequency requirements of the application. A 4 x 250 W SSPA at 2,450 MHz SSMGS has been used for the chemical processes oven, while the almond drying application needs 4 x 500 W SSPA at 915 MHz. Both SSMGS allow the individual or combined digital control of the parameters of the four amplifying modules, i.e., power, frequency and phase.
Multiphysics modelling has been thoroughly studied with special attention to the temperature-dependent thermophysical and dielectric properties of food and liquid solutions. The overall applicators' behaviour has been analysed with this tool. After completing the two PoC (Proof of Concept), the results show good agreement with the models. Both PoCs have shown promising improvements to the current state-of-the-art systems. The chemical applications PoC shows electromagnetic field distribution improvements, independent of the application or load. On the other hand, the almonds drying system provides increased control over the process avoiding material losses through overheating.Santón Pons, P. (2022). Design and Development of a Multi-Frequency System for Microwave Heating [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/19132
Advanced Nanomaterials for Electrochemical Energy Conversion and Storage
This book focuses on advanced nanomaterials for energy conversion and storage, covering their design, synthesis, properties and applications in various fields. Developing advanced nanomaterials for high-performance and low-cost energy conversion and storage devices and technologies is of great significance in order to solve the issues of energy crisis and environmental pollution. In this book, various advanced nanomaterials for batteries, capacitors, electrocatalysis, nanogenerators, and magnetic nanomaterials are presente
WiGlove : A Passive Dynamic Orthosis for Home-based Post-stroke Rehabilitation of Hand and Wrist
Stroke survivors often experience varying levels of motor function deficits in their hands
affecting their ability to perform activities of daily life. Recovering their hand functions
through neurorehabilitation is a significant step in their recovery towards independent
living. Home-based rehabilitation using robotic devices allows stroke survivors to train at their
convenience independent of factors such as the availability of therapists’ appointments and the
need for frequent travel to outpatient clinics. While many robotic solutions have been proposed
to address the above concerns, most focus on training only the wrist or the fingers, neglecting
the synergy between the two. To address this, the WiGlove was co-designed to allow hemiparetic
stroke survivors to train both the wrist and fingers in the comfort of their homes.
The central hypothesis of this work is to investigate if a device designed using user-centred
methods featuring aspects of usability such as easy donning and doffing and wireless operation,
can act as a feasible tool for home-based rehabilitation of the hand and wrist following stroke. In
order to aid this investigation, we tackled this task in three stages of usability and feasibility
evaluations.
Firstly, healthy participants tried the current state of the art, the SCRIPT Passive Orthosis, as
well as the WiGlove, in a counterbalanced, within-subject experiment and attested to WiGlove’s
improvement in several aspects of usability such as ease of don/doffing, suitability for ADL,
unblocked natural degrees of freedom, safety and aesthetic appeal. Subsequently, a heuristic
evaluation with six stroke therapists validated these improvements and helped identify issues
they perceived to potentially affect the device’s acceptance. Integrating this feedback, the updated
WiGlove was subjected to a six-week summative feasibility evaluation with two stroke survivors,
with varying levels of impairment, in their homes without supervision from the therapists.
Results from this study were overwhelmingly positive on the usability and acceptance of the
WiGlove. Furthermore, in the case of the first participant who trained with it for a total of 39
hours, notable improvements were observed in the participant’s hand functions. It showed that
even without a prescribed training protocol, both participants were willing to train regularly
with the WiGlove and its games, sometimes several times a day. These results demonstrate that
WiGlove can be a promising tool for home-based rehabilitation for stroke survivors and serve as
evidence for a larger user study with more participants with varying levels of motor impairments
due to stroke.
The findings of this study also offer preliminary evidence supporting the effectiveness of
training with the WiGlove, particularly in the case of the first participant, who exhibited a
significant reduction of tone in the hand as a result of increased training intensity. Owing to the
participant’s satisfaction with the device, it was requested by him to extend his involvement in
the study by using the WiGlove for a longer duration which was facilitated
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