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Siedlungswasserwirtschaft
(2012)
Siedlungswasserwirtschaft
(2009)
Siedlungswasserwirtschaft
(2015)
Nachfolgende Ausführungen und Berechnungsbeispiele beziehen sich auf Kapitel 19 Siedlungswasserwirtschaft im „Wendehorst: Bautechnische Zahlentafeln 35. Auflage 2015“ (abgekürzt: BZ). Für den Bau von Anlagen der Siedlungswasserwirtschaft sind ebenso die Grundlagen der Hydraulik zu berücksichtigen. Aus diesem Grunde sind auch die entsprechenden Ausführungen zur Hydraulik zu beachten.
We present an electromechanically coupled Finite Element model for cardiac tissue. It bases on the mechanical model for cardiac tissue of Hunter et al. that we couple to the McAllister-Noble-Tsien electrophysiological model of purkinje fibre cells. The corresponding system of ordinary differential equations is implemented on the level of the constitutive equations in a geometrically and physically nonlinear version of the so-called edge-based smoothed FEM for plates. Mechanical material parameters are determined from our own pressure-deflection experimental setup. The main purpose of the model is to further examine the experimental results not only on mechanical but also on electrophysiological level down to ion channel gates. Moreover, we present first drug treatment simulations and validate the model with respect to the experiments.
Skizze
(2008)
Small Claims Regulation
(2017)
Stand 01.01.2022 sind in Deutschland 618.460 elektrisch angetriebene KFZ zugelassen. Insgesamt sind derzeit 48.540.878 KFZ zugelassen, was einer Elektromobilitätsquote von ca. 1,2 % entspricht. Derzeit werden Elektromobile über Ladestationen oder Steckdosen mit dem Stromnetz verbunden und üblicherweise mit der vollen Ladekapazität des Anschlusses aufgeladen, bis das Batteriemanagementsystem des Fahrzeugs abhängig vom Ladezustand der Batterie die Ladeleistung reduziert.
Solar sails are large and lightweight reflective structures that are propelled by solar radiation pressure. This chapter covers their orbital and attitude dynamics and control. First, the advantages and limitations of solar sails are discussed and their history and development status is outlined. Because the dynamics of solar sails is governed by the (thermo-)optical properties of the sail film, the basic solar radiation pressure force models have to be described and compared before parameters to measure solar sail performance can be defined. The next part covers the orbital dynamics of solar sails for heliocentric motion, planetocentric motion, and motion at Lagrangian equilibrium points. Afterwards, some advanced solar radiation pressure force models are described, which allow to quantify the thrust force on solar sails of arbitrary shape, the effects of temperature, of light incidence angle, of surface roughness, and the effects of optical degradation of the sail film in the space environment. The orbital motion of a solar sail is strongly coupled to its rotational motion, so that the attitude control of these soft and flexible structures is very challenging, especially for planetocentric orbits that require fast attitude maneuvers. Finally, some potential attitude control methods are sketched and selection criteria are given.
Concorde (Figure 9) is the only supersonic airliner which has been introduced into regular passenger service. It is still in service at British Airways and Air France without any flight accidents, and probably will stay in service for at least for ten more years.
Speicheroptimierung
(2011)
In dieser Lektion wurden beginnend mit der Darstellung des fundamentalen Wandels
des Gasmarktes die daraus folgenden Implikationen für die Einsatzweise von
Gasspeichern abgeleitet. Anschließend wurden zwei Bewertungs- und Steuerungsverfahren für einen Gasspeicher an den beiden Marktstufen Termin- und Spotmarkt methodisch vorgestellt und anhand von Beispielrechnungen illustriert.
Das Verfahren zur Bewertung und Steuerung im Terminmarkt stellt ein sehr
robustes und methodisch einfaches Verfahren dar. Hierbei wird die Saisonalität
der Forwardkurve bzw. deren Veränderungen arbitragefrei mithilfe des Speichers
ausgenutzt. Dieses Verfahren kann nicht den gesamten Zeitwert des Speichers
ausweisen. Es zieht in jedem Zeitpunkt nur die aktuellen Informationen der Forwardkurve zur Entscheidung heran. Es bildet aber keine bedingte Erwartung über
zukünftige Erträge und deren Beeinflussung durch die aktuelle Speicherfahrweise,
um hieraus eine optimale Entscheidung zu formulieren.
Bei der Bewertung gegenüber dem Spotmarkt mithilfe der Least-Squares-Monte-
Carlo-Simulation wird in einer stochastischen Optimierung dagegen der volle Zeitwert des Speichers und damit der gesamte Zusatznutzen der Flexibilität ermittelt. Hierdurch leiten sich auch wesentlich andere Hedging-Empfehlungen als im ersten Verfahren ab, um diesen zu sichern. Der Einsatz der beiden Verfahren im Alltag zur Bewirtschaftung des Speichers hängt insbesondere vom Know-how, den Speicherparametern und der Risikobereitschaft des Handels ab. Beide Strategien liefern hierzu Hedging-Empfehlungen ab, mit welchem der zugrunde liegende Wert gesichert werden kann. Risikoaverse Händler, die einen Großteil des inneren Wertes sichern wollen, könnten im Terminmarkt einen Großteil des Speichers mithilfe des „Intrinsic Rolling“-Verfahrens bewirtschaften. Sie würden hierdurch den saisonalen Spread in der Forwardkurve rollierend sichern. Gleichzeitig kann ein kleinerer Anteil mithilfe der stochastischen Optimierung und den damit verbundenen Ausübungsgrenzen gegenüber dem Spotmarkt bewirtschaftet werden.
In einem liquiden vollständigen Markt wird eine Steuerung des Speichers allein
gegenüber den vorhandenen Marktstufen vorgenommen und der Wert für alle
Marktteilnehmer objektiv messbar. Für den Fall, dass der Markt illiquide ist und
hierdurch z. B. eine Kundenlast nicht allein am Termin- und Spotmarkt jederzeit
gedeckt werden kann, erscheint es notwendig, den Speicher im Kontext einer Portfoliooptimierung zu bewerten. Dies wird in der nächsten Lektion vorgenommen.
Hierbei ist aber zu beachten, dass der Speicher dadurch eine individualisierte Wertkomponente erhält, die von der konkreten Ausgestaltung des jeweiligen Portfolios abhängt.
Stahlbau
(2012)
Stahlbau
(2005)
Stahlbau
(2012)
Stahlbau
(2015)
Es ist zwischen Stählen bis S460 und solchen mit höherer Streckgrenze zu unterscheiden. Stähle bis S460 sind auch für die plastische Tragwerksberechnung nach dem Fließgelenkverfahren zugelassen. Bei Stählen oberhalb S460 bis S700 ist neben der elastischen eine nichtlineare plastische Tragwerksberechnung unter Berücksichtigung von Teilplastizierungen von Bauteilen in Fließzonen möglich.
Stahlbau
(2015)
Stahlbau
(2009)
Die bauaufsichtliche Einführung der Eurocodes steht unmittelbar bevor. Für den Bereich des Stahl- und Spannbetonbaus soll die Anwendung zum 1. Juli 2012 verbindlich sein, d. h. mit diesem Stichtag sollte nur noch der Eurocode 2 (DIN EN 1992-1-1, Ausgabe Januar 2011) mit seinem zugehörigen nationalen Anhang (DIN EN 1992-1-1/NA, Ausgabe Januar 2011) Verwendung finden, die DIN 1045-1 wird zurückgezogen. Bereits seit März 2010 gilt eine Übergangsphase, ist der die Anwendung des Eurocodes alternativ zur DIN 1045-1 als bauaufsichtlich gleichwertige Lösung möglich.
Stahlbetonbau
(2012)
Stahlbetonbau
(2009)
Stahlbetonbau
(2015)
Das Kapitel Stahlbetonbau besteht aus einer Formelsammlung (Teil A) sowie einem Praxisbeispiel (Teil B). In dem Praxisbeispiel werden exemplarisch die erforderlichen Rechenschritte und Nachweise zur Bemessung im GZT und GZG nach Eurocode 2 [1] vorgestellt. Die Hinweise im Text beziehen sich, soweit nicht explizit erwähnt, auf Wendehorst, Bautechnische Zahlentafeln, 35. Auflage, „Stahlbeton- und Spannbetonbau nach Eurocode 2“ [2]. Die zum Praxisbeispiel zugehörigen Konstruktions- und Bewehrungszeichnungen stehen im Onlineportal zu diesem Buch zum kostenlosen Download bereit (siehe unter www.springer.com).
Wind loads have great impact on many engineering structures. Wind storms often cause irreparable damage to the buildings which are exposed to it. Along with the earthquakes, wind represents one of the most common environmental load on structures and is relevant for limit state design. Modern wind codes indicate calculation procedures allowing engineers to deal with structural systems, which are susceptible to conduct wind-excited oscillations. In the codes approximate formulas for wind buffeting are specified which relate the dynamic problem to rather abstract parameter functions. The complete theory behind is not visible in order to simplify the applicability of the procedures. This chapter derives the underlying basic relations of the spectral method for wind buffeting and explains the main important applications of it in order to elucidate part of the theoretical background of computations after the new codes. The stochasticity of the wind processes is addressed, and the analysis of analytical as well as measurement based power spectra is outlined. Short MATLAB codes are added to the Appendix 3 which carry out the computation of a single sided auto-spectrum from a statistically stationary, discrete stochastic process. Two examples are presented.
This chapter describes three general strategies to master uncertainty in technical systems: robustness, flexibility and resilience. It builds on the previous chapters about methods to analyse and identify uncertainty and may rely on the availability of technologies for particular systems, such as active components. Robustness aims for the design of technical systems that are insensitive to anticipated uncertainties. Flexibility increases the ability of a system to work under different situations. Resilience extends this characteristic by requiring a given minimal functional performance, even after disturbances or failure of system components, and it may incorporate recovery. The three strategies are described and discussed in turn. Moreover, they are demonstrated on specific technical systems.
Styling
(2008)
Supersonic laminar flow
(1997)
Supersonic transports are very drag sensitive. Technology to reduce drag by application of laminar flow, therefore, will be important; it is a prerequisite to achieve very long range capability. In earlier studies it was assumed that SCTs would only become possible by application of laminar flow [376]. But today, we request an SCT to be viable without application of laminar flow in order to maintain its competitiveness when laminar flow becomes available for subsonic and supersonic transports. By reducing fuel burned, laminar flow drag reduction reduces size and weight of the aircraft, or increases range capability -whereas otherwise size and weight would grow towards infinity. Transition mechanisms from laminar to turbulent state of the boundary layer flow (ALT, CFI, TSI) function as for transonic transports, but at more severe conditions: higher sweep angles, cooled surfaces; higher mode instabilities (HMI) must at least be taken into account, although they may not become important below Mach 3. Hitherto there is a worldwide lack of ground test facilities to investigate TSI at the expected cruise Mach numbers between 1.6 and 2.4; in Stuttgart, Germany one such facility -a Ludwieg tube- is still in the validation phase. A quiet Ludwieg tunnel could be a favourable choice for Europe. But it will require a new approach in designing aircraft which includes improved theoretical predictions, usage of classical wind tunnels for turbulent flow and flight tests for validation.
This chapter introduces performance and acceptance testing and describes state-of-the-art tools, methods, and instruments to assess the plant performance or realize plant acceptance testing. The status of the development of standards for performance assessment is given.
The methodological discourse of mixed-methods research offers general procedures to combine quantitative and qualitative methods for investigating complex fields of research such as higher education. However, integrating different methods still poses considerable challenges. To move beyond general recommendations for mixed-methods research, this chapter proposes to discuss methodological issues with respect to a particular research domain. Taking current studies on the transition to higher education as an example, the authors first provide an overview of the potentials and limitations of quantitative and qualitative methods in the research domain. Second, they show the need for a conceptual framework grounded in the theory of the research object to guide the integration of different methods and findings. Finally, an example study that investigates transition with regard to the interplay of the individual student and the institutional context serves to illustrate the guiding role of theory. The framework integrates different theoretical perspectives on transition, informs the selection of the research methods, and defines the nexus of the two strands that constitute the mixed-methods design. As the interplay of individual and context is of concern for teaching and learning in general, the example presented may be fruitful for the wider field of higher education research.
The method of fundamental solutions is applied to the approximate computation of interior transmission eigenvalues for a special class of inhomogeneous media in two dimensions. We give a short approximation analysis accompanied with numerical results that clearly prove practical convenience of our alternative approach.
The problem of creation and use of sorption materials is of current interest for the practice of the modern medicine and agriculture. Practical importance is production of a biostimulant using a carbon sorbent for a significant increase in productivity, which is very relevant for the regions of Kazakhstan. It is known that a plant phytohormone—fusicoccin—in nanogram concentrations transforms cancer cells to the state of apoptosis. In this regard, there is a scientific practical interest in the development of a highly efficient method for producing fusicoccin from extract of germinated wheat seeds. According to the results of computer modeling, cleaning composite components of fusicoccin using microporous carbon adsorbents not suitable as the size of the molecule of fusicoccin more than micropores and the optimum pore size for purification of constituents of fusicoccin was determined by computer simulation.
We present a robotic tool that autonomously follows a conversation to enable remote presence in video conferencing. When humans participate in a meeting with the help of video conferencing tools, it is crucial that they are able to follow the conversation both with acoustic and visual input. To this end, we design and implement a video conferencing tool robot that uses binaural sound source localization as its main source to autonomously orient towards the currently talking speaker. To increase robustness of the acoustic cue against noise we supplement the sound localization with a source detection stage. Also, we include a simple onset detector to retain fast response times. Since we only use two microphones, we are confronted with ambiguities on whether a source is in front or behind the device. We resolve these ambiguities with the help of face detection and additional moves. We tailor the system to our target scenarios in experiments with a four minute scripted conversation. In these experiments we evaluate the influence of different system settings on the responsiveness and accuracy of the device.
Themen
(2019)
Thermal management in E-carsharing vehicles - preconditioning concepts of passenger compartments
(2015)
The issue of thermal management in electric vehicles includes the topics of drivetrain cooling and heating, interior temperature, vehicle body conditioning and safety. In addition to the need to ensure optimal thermal operating conditions of the drivetrain components (drive motor, battery and electrical components), thermal comfort must be provided for the passengers. Thermal comfort is defined as the feeling which expresses the satisfaction of the passengers with the ambient conditions in the compartment. The influencing factors on thermal comfort are the temperature and humidity as well as the speed of the indoor air and the clothing and the activity of the passengers, in addition to the thermal radiation and the temperatures of the interior surfaces. The generation and the maintenance of free visibility (ice- and moisture-free windows) count just as important as on-demand heating and cooling of the entire vehicle. A Carsharing climate concept of the innovative ec2go vehicle stipulates and allows for only seating areas used by passengers to be thermally conditioned in a close-to-body manner. To enable this, a particular feature has been added to the preconditioning of the Carsharing electric vehicle during the electric charging phase at the parking station.
Nanotubular tobacco mosaic virus (TMV) particles and RNA-free lower-order coat protein (CP) aggregates have been employed as enzyme carriers in different diagnostic layouts and compared for their influence on biosensor performance. In the following, we describe a label-free electrochemical biosensor for improved glucose detection by use of TMV adapters and the enzyme glucose oxidase (GOD). A specific and efficient immobilization of streptavidin-conjugated GOD ([SA]-GOD) complexes on biotinylated TMV nanotubes or CP aggregates was achieved via bioaffinity binding. Glucose sensors with adsorptively immobilized [SA]-GOD, and with [SA]-GOD cross-linked with glutardialdehyde, respectively, were tested in parallel on the same sensor chip. Comparison of these sensors revealed that TMV adapters enhanced the amperometric glucose detection remarkably, conveying highest sensitivity, an extended linear detection range and fastest response times. These results underline a great potential of an integration of virus/biomolecule hybrids with electronic transducers for applications in biosensorics and biochips. Here, we describe the fabrication and use of amperometric sensor chips combining an array of circular Pt electrodes, their loading with GOD-modified TMV nanotubes (and other GOD immobilization methods), and the subsequent investigations of the sensor performance.