@article{MaurerRiekeSchemmetal.2023, author = {Maurer, Florian and Rieke, Christian and Schemm, Ralf and Stollenwerk, Dominik}, title = {Analysis of an urban grid with high photovoltaic and e-mobility penetration}, series = {Energies}, volume = {16}, journal = {Energies}, number = {8}, publisher = {MDPI}, address = {Basel}, issn = {1996-1073}, doi = {10.3390/en16083380}, pages = {18 Seiten}, year = {2023}, abstract = {This study analyses the expected utilization of an urban distribution grid under high penetration of photovoltaic and e-mobility with charging infrastructure on a residential level. The grid utilization and the corresponding power flow are evaluated, while varying the control strategies and photovoltaic installed capacity in different scenarios. Four scenarios are used to analyze the impact of e-mobility. The individual mobility demand is modelled based on the largest German studies on mobility "Mobilit{\"a}t in Deutschland", which is carried out every 5 years. To estimate the ramp-up of photovoltaic generation, a potential analysis of the roof surfaces in the supply area is carried out via an evaluation of an open solar potential study. The photovoltaic feed-in time series is derived individually for each installed system in a resolution of 15 min. The residential consumption is estimated using historical smart meter data, which are collected in London between 2012 and 2014. For a realistic charging demand, each residential household decides daily on the state of charge if their vehicle requires to be charged. The resulting charging time series depends on the underlying behavior scenario. Market prices and mobility demand are therefore used as scenario input parameters for a utility function based on the current state of charge to model individual behavior. The aggregated electricity demand is the starting point of the power flow calculation. The evaluation is carried out for an urban region with approximately 3100 residents. The analysis shows that increased penetration of photovoltaics combined with a flexible and adaptive charging strategy can maximize PV usage and reduce the need for congestion-related intervention by the grid operator by reducing the amount of kWh charged from the grid by 30\% which reduces the average price of a charged kWh by 35\% to 14 ct/kWh from 21.8 ct/kWh without PV optimization. The resulting grid congestions are managed by implementing an intelligent price or control signal. The analysis took place using data from a real German grid with 10 subgrids. The entire software can be adapted for the analysis of different distribution grids and is publicly available as an open-source software library on GitHub.}, language = {en} } @misc{SteuerDankertBernhardLangolfetal.2023, author = {Steuer-Dankert, Linda and Bernhard, Sebastian and Langolf, Jessica and Leicht-Scholten, Carmen}, title = {About the paradox of sustainable production and what we can do about it!}, series = {Joint SCORAI-ERSCP-WUR conference on transforming consumption-production systems toward just and sustainable futures (SCP23), July 5-8, 2023, Wageningen, The Netherlands}, journal = {Joint SCORAI-ERSCP-WUR conference on transforming consumption-production systems toward just and sustainable futures (SCP23), July 5-8, 2023, Wageningen, The Netherlands}, year = {2023}, abstract = {Sustainability is playing an increasingly important role. Not least due to the definition of the sustainable development goals (SDGs) in the framework of the agenda 2030 by the United Nations (UN) in 2015 (United Nations, n.d.), it has become clear that the cooperation of different actors is needed to achieve the defined 17 goals. Industry, as a global actor, has a special role to play in this. In the course of sustainable production processes and chains, the industry is confronted with the responsibility of reflecting on the consequences of its own trade on an ecological, economic, and also social level and deriving measures that, according to the definition of sustainability (Hauff, 1987), will also enable future generations to satisfy their needs. While the ecological pillar of sustainability is already being addressed by different industrial initiatives (Deloitte, 2021), it is questionable to what extent the economic and, above all, the social pillars of sustainability also play a decisive role. Accordingly, it is questionable to what extent sustainability in its triad of social, ecological, and economic aspects is taken into account holistically at all, and thus to what extent the industry contributes to achieving the 17 goals defined by the UN. This paper presents a qualitative study that explores these questions. Interviewing 31 representatives from the manufacturing industry in Germany, results indicate a Paradox of Sustainable Production expressed by a theoretical reflection of the need for focusing on people in production processes on the one hand and a lack of addressing the social pillar of sustainability in concepts on the other hand. However, while it is a troublesome finding given the striking need for sustainable development (The-Sustainable-Development-Goals-Report-2022; Kropp 2019; von Hauff 2021; Roy and Singh 2017), the paradox directly lays out a path of resolving it. This is because, given its nature, we can see that we could resolve it via the implementation of strong educational efforts trying to help the respective people of the manufacturing industry to understand the holistic and interdependent character of sustainable development (The-Sustainable-Development-Goals-Report-2022).}, language = {en} } @article{HoffstadtCheenakulaNikolauszetal.2023, author = {Hoffstadt, Kevin and Cheenakula, Dheeraja and Nikolausz, Marcell and Krafft, Simone and Harms, Hauke and Kuperjans, Isabel}, title = {Design and construction of a new reactor for flexible biomethanation of hydrogen}, series = {Fermentation}, volume = {9}, journal = {Fermentation}, number = {8}, publisher = {MDPI}, address = {Basel}, issn = {2311-5637}, doi = {10.3390/fermentation9080774}, pages = {1 -- 16}, year = {2023}, abstract = {The increasing share of renewable electricity in the grid drives the need for sufficient storage capacity. Especially for seasonal storage, power-to-gas can be a promising approach. Biologically produced methane from hydrogen produced from surplus electricity can be used to substitute natural gas in the existing infrastructure. Current reactor types are not or are poorly optimized for flexible methanation. Therefore, this work proposes a new reactor type with a plug flow reactor (PFR) design. Simulations in COMSOL Multiphysics ® showed promising properties for operation in laminar flow. An experiment was conducted to support the simulation results and to determine the gas fraction of the novel reactor, which was measured to be 29\%. Based on these simulations and experimental results, the reactor was constructed as a 14 m long, 50 mm diameter tube with a meandering orientation. Data processing was established, and a step experiment was performed. In addition, a kLa of 1 h-1 was determined. The results revealed that the experimental outcomes of the type of flow and gas fractions are in line with the theoretical simulation. The new design shows promising properties for flexible methanation and will be tested.}, language = {en} } @article{CheenakulaHoffstadtKrafftetal.2022, author = {Cheenakula, Dheeraja and Hoffstadt, Kevin and Krafft, Simone and Reinecke, Diana and Klose, Holger and Kuperjans, Isabel and Gr{\"o}mping, Markus}, title = {Anaerobic digestion of algal-bacterial biomass of an Algal Turf Scrubber system}, series = {Biomass Conversion and Biorefinery}, volume = {13}, journal = {Biomass Conversion and Biorefinery}, publisher = {Springer}, address = {Berlin}, issn = {2190-6823}, doi = {10.1007/s13399-022-03236-z}, pages = {15 Seiten}, year = {2022}, abstract = {This study investigated the anaerobic digestion of an algal-bacterial biofilm grown in artificial wastewater in an Algal Turf Scrubber (ATS). The ATS system was located in a greenhouse (50°54′19ʺN, 6°24′55ʺE, Germany) and was exposed to seasonal conditions during the experiment period. The methane (CH4) potential of untreated algal-bacterial biofilm (UAB) and thermally pretreated biofilm (PAB) using different microbial inocula was determined by anaerobic batch fermentation. Methane productivity of UAB differed significantly between microbial inocula of digested wastepaper, a mixture of manure and maize silage, anaerobic sewage sludge, and percolated green waste. UAB using sewage sludge as inoculum showed the highest methane productivity. The share of methane in biogas was dependent on inoculum. Using PAB, a strong positive impact on methane productivity was identified for the digested wastepaper (116.4\%) and a mixture of manure and maize silage (107.4\%) inocula. By contrast, the methane yield was significantly reduced for the digested anaerobic sewage sludge (50.6\%) and percolated green waste (43.5\%) inocula. To further evaluate the potential of algal-bacterial biofilm for biogas production in wastewater treatment and biogas plants in a circular bioeconomy, scale-up calculations were conducted. It was found that a 0.116 km2 ATS would be required in an average municipal wastewater treatment plant which can be viewed as problematic in terms of space consumption. However, a substantial amount of energy surplus (4.7-12.5 MWh a-1) can be gained through the addition of algal-bacterial biomass to the anaerobic digester of a municipal wastewater treatment plant. Wastewater treatment and subsequent energy production through algae show dominancy over conventional technologies.}, language = {en} } @misc{SteuerDankertBernhardLangolfetal.2022, author = {Steuer-Dankert, Linda and Bernhard, Sebastian and Langolf, Jessica and Leicht-Scholten, Carmen}, title = {Managing change and acceptance of digitalization strategies - Implementing the vision of „Internet of Production" (IoP) in existing corporate structures}, series = {Textile Impulse f{\"u}r die Zukunft: Aachen-Dresden-Denkendorf International Textile Conference 2022 : 1. - 2. Dezember 2022, Eurogress Aachen}, journal = {Textile Impulse f{\"u}r die Zukunft: Aachen-Dresden-Denkendorf International Textile Conference 2022 : 1. - 2. Dezember 2022, Eurogress Aachen}, pages = {153 -- 153}, year = {2022}, abstract = {The vision of the Internet of Production is to enable a new level of crossdomain collaboration by providing semantically adequate and context-aware data from production, development \& usage in real-time.}, language = {en} } @article{SchuellerRuhlDinstuehlerSengeretal.2022, author = {Sch{\"u}ller-Ruhl, Aaron and Dinst{\"u}hler, Leonard and Senger, Thorsten and Bergfeld, Stefan and Ingenhag, Christian and Fleischhaker, Robert}, title = {Direct fabrication of arbitrary phase masks in optical glass via ultra-short pulsed laser writing of refractive index modifications}, series = {Applied Physics B}, volume = {128}, journal = {Applied Physics B}, number = {Article number: 208}, editor = {Mackenzie, Jacob}, publisher = {Springer}, address = {Berlin}, issn = {1432-0649 (Online)}, doi = {10.1007/s00340-022-07928-2}, pages = {1 -- 11}, year = {2022}, abstract = {We study the possibility to fabricate an arbitrary phase mask in a one-step laser-writing process inside the volume of an optical glass substrate. We derive the phase mask from a Gerchberg-Saxton-type algorithm as an array and create each individual phase shift using a refractive index modification of variable axial length. We realize the variable axial length by superimposing refractive index modifications induced by an ultra-short pulsed laser at different focusing depth. Each single modification is created by applying 1000 pulses with 15 μJ pulse energy at 100 kHz to a fixed spot of 25 μm diameter and the focus is then shifted axially in steps of 10 μm. With several proof-of-principle examples, we show the feasibility of our method. In particular, we identify the induced refractive index change to about a value of Δn=1.5⋅10-3. We also determine our current limitations by calculating the overlap in the form of a scalar product and we discuss possible future improvements.}, language = {en} } @article{HeelDiktaBraekers2021, author = {Heel, Mareike van and Dikta, Gerhard and Braekers, Roel}, title = {Bootstrap based goodness‑of‑fit tests for binary multivariate regression models}, series = {Journal of the Korean Statistical Society}, volume = {51}, journal = {Journal of the Korean Statistical Society}, publisher = {Springer Nature}, address = {Singapur}, issn = {2005-2863 (Online)}, doi = {10.1007/s42952-021-00142-4}, pages = {28 Seiten}, year = {2021}, abstract = {We consider a binary multivariate regression model where the conditional expectation of a binary variable given a higher-dimensional input variable belongs to a parametric family. Based on this, we introduce a model-based bootstrap (MBB) for higher-dimensional input variables. This test can be used to check whether a sequence of independent and identically distributed observations belongs to such a parametric family. The approach is based on the empirical residual process introduced by Stute (Ann Statist 25:613-641, 1997). In contrast to Stute and Zhu's approach (2002) Stute \& Zhu (Scandinavian J Statist 29:535-545, 2002), a transformation is not required. Thus, any problems associated with non-parametric regression estimation are avoided. As a result, the MBB method is much easier for users to implement. To illustrate the power of the MBB based tests, a small simulation study is performed. Compared to the approach of Stute \& Zhu (Scandinavian J Statist 29:535-545, 2002), the simulations indicate a slightly improved power of the MBB based method. Finally, both methods are applied to a real data set.}, language = {en} } @article{BlankeHagenkampDoeringetal.2021, author = {Blanke, Tobias and Hagenkamp, Markus and D{\"o}ring, Bernd and G{\"o}ttsche, Joachim and Reger, Vitali and Kuhnhenne, Markus}, title = {Net-exergetic, hydraulic and thermal optimization of coaxial heat exchangers using fixed flow conditions instead of fixed flow rates}, series = {Geothermal Energy}, volume = {9}, journal = {Geothermal Energy}, number = {Article number: 19}, publisher = {Springer}, address = {Berlin}, issn = {2195-9706}, doi = {10.1186/s40517-021-00201-3}, pages = {23 Seiten}, year = {2021}, abstract = {Previous studies optimized the dimensions of coaxial heat exchangers using constant mass fow rates as a boundary condition. They show a thermal optimal circular ring width of nearly zero. Hydraulically optimal is an inner to outer pipe radius ratio of 0.65 for turbulent and 0.68 for laminar fow types. In contrast, in this study, fow conditions in the circular ring are kept constant (a set of fxed Reynolds numbers) during optimization. This approach ensures fxed fow conditions and prevents inappropriately high or low mass fow rates. The optimization is carried out for three objectives: Maximum energy gain, minimum hydraulic efort and eventually optimum net-exergy balance. The optimization changes the inner pipe radius and mass fow rate but not the Reynolds number of the circular ring. The thermal calculations base on Hellstr{\"o}m's borehole resistance and the hydraulic optimization on individually calculated linear loss of head coefcients. Increasing the inner pipe radius results in decreased hydraulic losses in the inner pipe but increased losses in the circular ring. The net-exergy diference is a key performance indicator and combines thermal and hydraulic calculations. It is the difference between thermal exergy fux and hydraulic efort. The Reynolds number in the circular ring is instead of the mass fow rate constant during all optimizations. The result from a thermal perspective is an optimal width of the circular ring of nearly zero. The hydraulically optimal inner pipe radius is 54\% of the outer pipe radius for laminar fow and 60\% for turbulent fow scenarios. Net-exergetic optimization shows a predominant infuence of hydraulic losses, especially for small temperature gains. The exact result depends on the earth's thermal properties and the fow type. Conclusively, coaxial geothermal probes' design should focus on the hydraulic optimum and take the thermal optimum as a secondary criterion due to the dominating hydraulics.}, language = {en} } @article{GeorgStollenwerkReinkensmeieretal.2021, author = {Georg, J{\"o}rg Heiner and Stollenwerk, Dominik and Reinkensmeier, Sebastian and Jungbluth, Christian}, title = {„Smartes" Laden an {\"o}ffentlich zug{\"a}nglichen Lades{\"a}ulen - Teil 1: Quo vadis, Marktdesign?}, series = {Energiewirtschaftliche Tagesfragen : et ; Zeitschrift f{\"u}r Energiewirtschaft, Recht, Technik und Umwelt}, volume = {71}, journal = {Energiewirtschaftliche Tagesfragen : et ; Zeitschrift f{\"u}r Energiewirtschaft, Recht, Technik und Umwelt}, number = {1/2}, publisher = {ETV Energieverlag}, address = {Essen}, isbn = {0720-6240}, issn = {0013-743X}, pages = {64 -- 69}, year = {2021}, language = {de} } @article{StollenwerkReinkensmeierGeorgetal.2021, author = {Stollenwerk, Dominik and Reinkensmeier, Sebastian and Georg, J{\"o}rg Heiner and Jungbluth, Christian}, title = {„Smartes" Laden an {\"o}ffentlich zug{\"a}nglichen Lades{\"a}ulen - Teil 2: USER-Verhalten und -Erwartungen}, series = {Energiewirtschaftliche Tagesfragen : et ; Zeitschrift f{\"u}r Energiewirtschaft, Recht, Technik und Umwelt}, volume = {71}, journal = {Energiewirtschaftliche Tagesfragen : et ; Zeitschrift f{\"u}r Energiewirtschaft, Recht, Technik und Umwelt}, number = {3}, publisher = {ETV Energieverlag}, address = {Essen}, isbn = {0720-6240}, issn = {0013-743X}, pages = {38 -- 42}, year = {2021}, language = {de} } @inproceedings{DalguerRenaultChurilovetal.2016, author = {Dalguer, Luis A. and Renault, Philippe and Churilov, Sergey and Butenweg, Christoph}, title = {Evaluation of fragility curves for a three-storey-reinforced-concrete mock-up of SMART 2013 project}, series = {Transactions, SMiRT-23 : 23rd Conference on Structural Mechanics in Reactor Technology : Manchester, United Kingdom - August 10-14, 2015}, booktitle = {Transactions, SMiRT-23 : 23rd Conference on Structural Mechanics in Reactor Technology : Manchester, United Kingdom - August 10-14, 2015}, organization = {Conference on Structural Mechanics in Reactor Technology <23, 2015, Manchester>}, pages = {1 -- 9}, year = {2016}, language = {en} } @inproceedings{ButenwegRosinKubalski2013, author = {Butenweg, Christoph and Rosin, Julia and Kubalski, Thomas}, title = {Seismic response of conventional and base-isolated liquid storage tanks}, series = {International Conference on Earthquake Engineering : 29.-31.05.2013, Skopje, Mazedonien}, booktitle = {International Conference on Earthquake Engineering : 29.-31.05.2013, Skopje, Mazedonien}, organization = {International Conference on Earthquake Engineering <2013, Skopje>}, pages = {1 -- 8}, year = {2013}, language = {en} } @inproceedings{ButenwegKleemannAltayetal.2013, author = {Butenweg, Christoph and Kleemann, Anne and Altay, Okyay and Renault, Philippe}, title = {Simulation of impact-loads on reinforced concrete structural elements}, series = {22nd International Conference on Structural Mechanics in Reactor Technology 2013 : (SMiRT 22) ; San Francisco, California, USA, 18 - 23 August 2013}, booktitle = {22nd International Conference on Structural Mechanics in Reactor Technology 2013 : (SMiRT 22) ; San Francisco, California, USA, 18 - 23 August 2013}, organization = {International Conference on Structural Mechanics in Reactor Technology, SMIRT <22, 2013, San Francisco, Calif.>}, pages = {1 -- 10}, year = {2013}, language = {en} } @incollection{BorchertHeimannSchemm2011, author = {Borchert, J{\"o}rg and Heimann, Thorsten and Schemm, Ralf}, title = {Speicheroptimierung}, series = {Gashandel und Gasbeschaffung}, booktitle = {Gashandel und Gasbeschaffung}, publisher = {Euroforum Verl.}, address = {D{\"u}sseldorf}, publisher = {Fachhochschule Aachen}, pages = {1 -- 69}, year = {2011}, abstract = {In dieser Lektion wurden beginnend mit der Darstellung des fundamentalen Wandels des Gasmarktes die daraus folgenden Implikationen f{\"u}r die Einsatzweise von Gasspeichern abgeleitet. Anschließend wurden zwei Bewertungs- und Steuerungsverfahren f{\"u}r 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 Saisonalit{\"a}t der Forwardkurve bzw. deren Ver{\"a}nderungen 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 {\"u}ber zuk{\"u}nftige Ertr{\"a}ge und deren Beeinflussung durch die aktuelle Speicherfahrweise, um hieraus eine optimale Entscheidung zu formulieren. Bei der Bewertung gegen{\"u}ber 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 Flexibilit{\"a}t 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 h{\"a}ngt 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 H{\"a}ndler, die einen Großteil des inneren Wertes sichern wollen, k{\"o}nnten im Terminmarkt einen Großteil des Speichers mithilfe des „Intrinsic Rolling"-Verfahrens bewirtschaften. Sie w{\"u}rden hierdurch den saisonalen Spread in der Forwardkurve rollierend sichern. Gleichzeitig kann ein kleinerer Anteil mithilfe der stochastischen Optimierung und den damit verbundenen Aus{\"u}bungsgrenzen gegen{\"u}ber dem Spotmarkt bewirtschaftet werden. In einem liquiden vollst{\"a}ndigen Markt wird eine Steuerung des Speichers allein gegen{\"u}ber den vorhandenen Marktstufen vorgenommen und der Wert f{\"u}r alle Marktteilnehmer objektiv messbar. F{\"u}r 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 n{\"a}chsten Lektion vorgenommen. Hierbei ist aber zu beachten, dass der Speicher dadurch eine individualisierte Wertkomponente erh{\"a}lt, die von der konkreten Ausgestaltung des jeweiligen Portfolios abh{\"a}ngt.}, language = {de} } @inproceedings{KernDikta2009, author = {Kern, Alexander and Dikta, Gerhard}, title = {Probability of damage of electrical and electronic systems due to indirect lightning flashes - investigation of data from German insurance companies}, year = {2009}, abstract = {In the presented paper data collected from the field related to damage statistics of electrical and electronic apparatus in household are reported and investigated. These damages (total number approx. 74000 cases), registered by five German insurance companies in 2005 and 2006, were adviced by customers as caused by lightning overvoltages. With the use of stochastical methods it is possible, to reasses the collected data and to distinguish between cases, which are with high probability caused by lightning overvoltages, and those, which are not. If there was an indication for a direct strike, this case was excluded, so the focus was only on indirect lightning flashes, i.e. only flashes to ground near the structure and flashes to or nearby an incoming service line were investigated. The data from the field contain the location of damaged apparatus (residence of the policy holder) and the distances of the nearest cloud-to-ground stroke to the location of the damage registered by the German lightning location network BLIDS at the date of damage. The statistical data along with some complementary numerical simulations allow to verify the correspondence of the Standards rules used for IEC 62305-2 with the field data and to define some correction needs. The results could lead to a better understanding whether a damage reported to an insurance company is really caused by indirect lightning, or not.}, subject = {Blitzschutz}, language = {en} } @misc{Kaster2009, author = {Kaster, Jan Mathis}, title = {Untersuchungen zur Specklereduktion bei der Infrarot-Laser gest{\"u}tzten Ferndetektion von TNT-Oberfl{\"a}chenkontaminationen}, year = {2009}, abstract = {Das Ziel der vorliegenden Arbeit ist die Specklereduktion bei der Infrarotlaser-gest{\"u}tzten abbildenden Ferndetektion von TNT-Oberfl{\"a}chenkontaminationen. F{\"u}r die Detektion wird die Probenoberfl{\"a}che mit einem abstimmbaren Quantenkaskadenlaser bei verschiedenen Wellenzahlen im Spektralbereich von 1340cm-1 bis 1380cm-1 bestrahlt, w{\"a}hrend eine Infrarot-Kamera Bilder der bestrahlten Fl{\"a}che aufzeichnet. Diese Bilder werden dann so verarbeitet, dass im Ausgabebild die chemisch spezifische TNT-Absorption durch eine {\"A}nderung der Helligkeit {\"o}rtlich aufgel{\"o}st erkennbar werden. Da koh{\"a}rente Strahlung, welche beispielsweise an optisch rauen Oberfl{\"a}chen reflektiert wird, aufgrund der stochastischen Verteilung der Oberfl{\"a}chenrautiefe mit der einfallenden Strahlung lateral unterschiedlich interferiert, entsteht ein „Rauschen" in der aufgezeichneten Strahlungsleistungsverteilung, das sog. Speckle-Ph{\"a}nomen. Die Empfindlichkeit der oben skizzierten Lasergest{\"u}tzten Messtechnik wird im Wesentlichen durch diesen Effekt limitiert. Um die durch Laserspeckles verursachten Rauschanteile zu reduzieren, gibt es verschiedene M{\"o}glichkeiten. Durch Reduktion von zeitlicher und r{\"a}umlicher Koh{\"a}renz der Strahlung wird deren Interferenzf{\"a}higkeit reduziert und durch Variieren des Specklemusters w{\"a}hrend einer Bildaufzeichnung f{\"u}hren Mittelungen unkorrelierter Rauschanteile zu einer Specklekontrastreduktion. Letztere M{\"o}glichkeit resultiert daraus, dass Laserspeckles statistisch durch die Familie der Gammaverteilungen beschrieben werden k{\"o}nnen. Demnach verbessert sich das Signal-zu-Rausch-Verh{\"a}ltnis mit der Anzahl gemittelter, unkorrelierter Rauschmuster proportional zur Wurzel dieser Anzahl. Ein im MIR-Spektralbereich umsetzbarer Ansatz, der all diese M{\"o}glichkeiten ber{\"u}cksichtigt, wurde bereits 1971 von Lowenthal und Joyeaux vorgeschlagen und im Rahmen der vorliegenden Arbeit f{\"u}r den infraroten Spektralbereich adaptiert. Dazu wird die Strahlung mit zwei CVD-Diamant-Wafern moduliert; ein Wafer ist dabei station{\"a}r und der andere rotiert mit ca. 70Hz. In der vorliegenden Arbeit konnte mit diesem Ansatz eine Verbesserung des Signal-zu-Rausch-Verh{\"a}ltnisses in der betrachteten Strahlungsleistungs¬verteilung von urspr{\"u}nglich 3 auf etwa 45 erzielt werden. So konnten erstmals TNT-Kontaminationen von bis zu 10µg/cm² in einem Abstand von 5m abbildend nachgewiesen werden. Dies entspricht der Kontamination durch einen mit TNT leicht verunreinigten Fingerabdruck.}, subject = {Speckle}, language = {de} } @article{WettingfeldKernKraemeretal.2009, author = {Wettingfeld, J{\"u}rgen and Kern, Alexander and Kr{\"a}mer, Heinz-Josef and Thorm{\"a}hlen, Reyno}, title = {International anerkannte Blitzschutznormen : Ausgewogener und sicherer Schutz}, publisher = {Fachhochschule Aachen}, address = {Aachen}, year = {2009}, abstract = {Die Einleitung zur Norm DIN EN 62305-3 beschreibt klar und ein - deutig: Der vorliegende Teil der IEC 62305 behandelt den Schutz von baulichen Anlagen gegen materielle Sch{\"a}den und den Schutz von Personen gegen Verletzungen durch Ber{\"u}hrungs- und Schrittspannungen. Als das wesentlichste und effektivste Mittel zum Schutz von baulichen Anlagen gegen materielle Sch{\"a}den gilt das Blitz - schutzsystem (LPS).}, subject = {Blitzschutz}, language = {de} } @inproceedings{KernBeierlZischank2009, author = {Kern, Alexander and Beierl, Ottmar and Zischank, Wolfgang}, title = {Calculation of the separation distance according to IEC 62305-3: 2006-10 - Remarks for the application and simplified methods}, year = {2009}, abstract = {[Paper of the X International Symposium on Lightning Protection 9th - 13th November, 2009 - Curitiba, Brazil. 6 pages] The international standard IEC 62305-3, published in 2006, requires as an integral part of the lightning protection system (LPS) the consideration of a separation distance between the conductors of the LPS and metal and electrical installations inside the structure to be protected. IEC 62305-3 gives two different methods for this calculation: a standard, simplified approach and a more detailed approach, which differ especially regarding the treatment of the current sharing effect on the LPS conductors. Hence, different results for the separation distance are possible, leading to some discrepancies in the use of the standard. The standard approach defined in the main part (Clause 6.3) and in Annex C of the standard in some cases may lead to a severe oversizing of the required separation distance. The detailed approach described in Annex E naturally gives more correct results. However, a calculation of the current sharing amongst all parts of the air-termination and downconductor network is necessary, in many cases requiring the use of network analysis programs. In this paper simplified methods for the assessment of the current sharing are presented, which are easy to use as well as sufficiently adequate.}, subject = {Blitzschutz}, language = {de} } @inproceedings{BehrensFrentzelKern2009, author = {Behrens, J{\"o}rg and Frentzel, Ralf and Kern, Alexander}, title = {Simulation der transienten Spannungsverl{\"a}ufe im Eigenbedarfsnetz eines Großkraftwerks bei einem kraftwerksnahen Blitzeinschlag in die Hochspannungs-Freileitung}, isbn = {978-3-8007-3197-8}, year = {2009}, abstract = {8. VDE/ABB-Blitzschutztagung, 29. - 30. Oktober 2009 in Neu-Ulm. Blitzschutztagung <8, 2009, Neu-Ulm> Berlin : VDE Verl. 2009 Großkraftwerke k{\"o}nnen durch Blitzentladungen mit potentiellen Auswirkungen auf deren Verf{\"u}gbarkeit und Sicherheit gef{\"a}hrdet werden. Ein sehr spezielles Szenario, welches aus aktuellem Anlass zu untersuchen war, betrifft den kraftwerksnahen Blitzeinschlag in die Hochspannungs-Freileitung am Netzanschluss der Anlage. Wird nun noch ein sogenannter Schirmfehler unterstellt, d.h. der direkte Blitzeinschlag erfolgt in ein Leiterseil des Hoch- bzw. H{\"o}chstspannungsnetzes und nicht in das dar{\"u}ber gespannte Erdseil, so bedeutet dies eine extreme elektromagnetische Einwirkung. Der vorliegende Beitrag befasst sich mit der Simulation eines solchen Blitzeinschlages und dessen Auswirkungen auf den Netzanschluss und die Komponenten der elektrischen Eigenbedarfsanlagen eines Kraftwerks auf den unterlagerten Spannungsebenen. Die dabei gewonnenen Erkenntnisse lassen sich ohne Einschr{\"a}nkungen auf Industrieanlagen mit Mittelspannungs-Netzanschluss und ohne eigener Stromversorgung {\"u}bertragen.}, subject = {Blitzschutz}, language = {de} } @inproceedings{GellertNordaButenweg2008, author = {Gellert, Christoph and Norda, Hannah and Butenweg, Christoph}, title = {Nonlinear behaviour of masonry under cyclic loading}, series = {7th European Conference on Structural Dynamics, EURODYN 2008 : 7-9 July 2008, Southampton}, booktitle = {7th European Conference on Structural Dynamics, EURODYN 2008 : 7-9 July 2008, Southampton}, organization = {European Conference on Structural Dynamics, EURODYN <7, 2008, Southampton>}, pages = {1 -- 12}, year = {2008}, language = {en} }