TY - JFULL ED - Engell, Lorenz ED - Siegert, Bernhard T1 - Schwerpunkt Synchronisation N2 - Nichts ist so aktuell wie die Gegenwart; gegenwärtig sein aber heißt gleichzeitig sein mit etwas anderem, und diese Gleichzeitigkeit muss immer eigens durch geeignete Operationen der Übertragung, der Überbrückung, der Abstimmung und ihre Werkzeuge hergestellt werden. So schlicht erklärt sich die grundlegende und aktuelle Relevanz des Themas der Synchronisierung ebenso wie seine kulturtechnische und medienphilosophische Ausformung. Die aktuelle medientheoretische und medienhistorische Aufmerksamkeit für die Verfertigung der Gegenwart (deren wichtigste Operation diejenige der Synchronisierung ist), wie sie sich auch im Jahresthema 2012/2013 der Forschungen am Internationalen Kolleg für Kulturtechnikforschung und Medienphilosophie (IKKM) niedergeschlagen hat, reagiert auf eine spezifische zeitphilosophische Spannungslage, die sich im Anschluss an die strukturale und poststrukturale sowie die systemtheoretische Differenztheorie einerseits und an eher empirische, phänomenale, aber auch technikhistorisch und -theoretisch relevante Sachverhalte andererseits ergeben hat. Den ersten Pol dieser Spannung bildet die Dekonstruktion der Präsenz, etwa, im Sinne Jacques Derridas, der Gleichzeitigkeit von Stimme und Ohr beim Sprechen, oder, im Sinne Deborah Eschs, der Live-Übertragung des Fernsehens. Den anderen Pol jedoch bilden die dennoch sich behauptenden phänomenalen und funktionalen Gleichzeitigkeitserfahrungen und -effekte. Sie umfassen etwa das Miterleben des Spielzuges im Sport, wie Hans Ulrich Gumbrecht es gefasst hat, und zahlreiche andere ästhetische, insbesondere erhabene Erfahrungen. Am anderen Ende der Skala gehören aber auch Prozesse wie die technische Einsteuerung und Abstimmung von Taktfrequenzen in Regelkreisen und Übertragungszusammenhängen zu den gültigen Formen effektiver Gleichzeitigkeit. Auch Verdichtungsvorgänge wie die mehr oder weniger instantane, ereignisbezogene wie ereignisförmige Bildung und Auflösung von Publika sind derlei relevante Präsenzeffekte. Die grundlegende Einsicht in die Gemachtheit und folglich Dekonstruierbarkeit der Gegenwart durch Synchronisierungs- und Desynchronisierungsoperationen jedenfalls widerstreitet nach medienwissenschaftlicher Überzeugung nicht ihrer Wirklichkeit im Sinne der Wirksamkeit – der lateinischen »actualitas«, als deren deutschsprachige Entsprechung die Scholastik des Mittelalters bei Meister Eckhart den Begriff der »Wirklichkeit« erst einführte. KW - Medienwissenschaft KW - Kulturwissenschaft Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20240507-48527 SN - 2366-0767 N1 - Lizenz CC-BY-NC-SA 3.0 VL - 2014 IS - 5.2014, Heft 2 PB - Felix Meiner Verlag CY - Hamburg ER - TY - JFULL ED - Engell, Lorenz ED - Siegert, Bernhard T1 - Focus Producing Places N2 - Producing places is a twofold topic. It can refer to places as sites that produce something, that are productive, that have operations unfold, or actions happen, or objects emerge. Or it can refer to the fabrication of places as specific entities themselves. With the extended availability and practicability of digital positioning, locating, and tracking systems, it has become evident that places are not just there, but that they are generated, that they are subject to mediatechnological operations and effects. Nonetheless, and at the same time, the aspect of places as being productive has also attracted considerable attention. Furthermore, in either perspective, a media-theoretical challenge has come up. It invests two different threads within the realm of conceptualizing not only space, but precisely place under conditions of media, both of them leading way back into the evolution of media societies and cultural technologies. KW - Medienwissenschaft KW - Kulturwissenschaft Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20240507-48519 SN - 2366-0767 N1 - Lizenz CC-BY-NC-SA 3.0 VL - 2014 IS - 5.2014, Heft 1 PB - Felix Meiner Verlag CY - Hamburg ER - TY - GEN A1 - Kleiner, Florian T1 - Charakterisierung des Einflusses der Wärmeleitfähigkeit von Kompositmaterialien auf die thermochemische Wärmespeicherung N2 - Mit dem stetigen Steigen des Anteils an erneuerbaren Energien wird der Einsatz von Speichern immer bedeutsamer. Neben der Speicherung elektrischer Energie ist die Speicherung anfallender solarer bzw. industrieller Wärme eine wichtige Herausforderung. Aufgrund der hohen Energiespeicherdichte kommt dabei der thermochemischen Wärmespeicherung eine entscheidende Rolle zu. Eine Klasse dieser Speichermaterialien bilden Kompositmaterialien, die aus einer offenporigen Matrix und einem darin eingelagerten Salzhydrat bestehen. Ausschlaggebend für eine hohe Speicherdichte ist bei dieser Materialklasse der schnelle Abtransport der durch Wasserdampfsorption entstandenen Wärme. Das entscheidende Kriterium für eine Anwendung als Speichermaterial ist somit die Wärmeleitfähigkeit des Materials. Im Rahmen der Arbeit wurden deshalb die Wärmeleitfähigkeiten ausgewählter Salze (NaCl, MgSO4 und ZnSO4) mit verschiedenen Kristallwassergehalten, Trägermaterialien wie Aktivkohle (Pellets und Pulver) und Zeolitpulver und an den daraus hergestellten Kompositmaterialien untersucht. Ziel war es außerdem Aussagen zu einer günstigen Materialkombination aus offenporigem Trägermaterial und Salzhydrat sowie eines geeigneten Porenfüllgrades zu treffen und Ansätze für die Modellierung der Wärmeleitfähigkeit der Komposite zu liefern. N2 - With the steady increase of renewable energies, the use of storage systems is becoming increasingly important. In addition to the storage of electrical energy, the storage of solar and industrial heat is an important challenge. Due to their high energy storage density, thermochemical heat storage materials are very promising. One class of these storage materials are composit materials, which consist of an porous matrix and an embedded salt hydrate. The decisive factor for a high storage density in this type of materials is the rapid removal of the heat generated by water vapor sorption. The decisive criterion for an application as a storage material is therefore the thermal conductivity of the material. The thermal conductivity of selected salts (NaCl, MgSO4 and ZnSO4) with different crystal water contents, carrier materials such as activated carbon (pellets and powder) and zeolite powder and the resulting composite materials were therefore investigated as part of the work. The aim was also to make statements on a favorable material combination of porous carrier material and salt hydrate as well as a suitable degree of pore filling and to provide approaches for modeling the thermal conductivity of the composites. KW - Wärmespeicher KW - Wärmeleitfähigkeit KW - Werkstoffkunde KW - Wärmespeicher KW - Wärmeleitfähigkeit KW - Hydratsalz KW - thermochemische Wärmespeicherung KW - thermochemical heat storage Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20210921-44968 ER - TY - THES A1 - Habtemariam, Abinet Kifle T1 - Numerical Demolition Analysis of a Slender Guyed Antenna Mast N2 - The main purpose of the thesis is to ensure the safe demolition of old guyed antenna masts that are located in different parts of Germany. The major problem in demolition of this masts is the falling down of the masts in unexpected direction because of buckling problem. The objective of this thesis is development of a numerical models using finite element method (FEM) and assuring a controlled collapse by coming up with different time setups for the detonation of explosives which are responsible for cutting down the cables. The result of this thesis will avoid unexpected outcomes during the demolition processes and prevent risk of collapsing of the mast over near by structures. KW - Abbruch KW - Finite-Elemente-Methode KW - Optimierung KW - Demolition KW - Guyed antenna masts KW - Explicit finite element method KW - Optimization Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20210723-44609 ER - TY - JOUR A1 - Chen, Zhen A1 - Schwing, Moritz A1 - Karlovšek, Jurij A1 - Wagner, Norman A1 - Scheuermann, Alexander T1 - Broadband Dielectric Measurement Methods for Soft Geomaterials: Coaxial Transmission Line Cell and Open-Ended Coaxial Probe JF - International Journal of Engineering and Technology N2 - Broadband dielectric measurement methods based on vector network analyzer coupled with coaxial transmission line cell (CC) and open-ended coaxial probe (OC) are simply reviewed, by which the dielectric behaviors in the frequency range of 1 MHz to 3 GHz of two practical geomaterials are investigated. Kaolin after modified compaction with different water contents is measured by using CC. The results are consistent with previous study on standardized compacted kaolin and suggest that the dielectric properties at frequencies below 100 MHz are not only a function of water content but also functions of other soil state parameters including dry density. The hydration process of a commercial grout is monitored in real time by using OC. It is found that the time dependent dielectric properties can accurately reveal the different stages of the hydration process. These measurement results demonstrate the practicability of the introduced methods in determining dielectric properties of soft geomaterials. KW - Impedanzspektroskopie KW - Electromagnetic properties of porous materials KW - Koaxialkabel KW - Dielectric spectroscopy KW - open-ended coaxial probe KW - coaxial transmission line KW - real-time monitoring KW - physicochemical properties of geomaterials Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20210408-43984 UR - http://www.ijetch.org/index.php?m=content&c=index&a=show&catid=58&id=838 VL - 2014 IS - volume 6, number 5 SP - 373 EP - 380 ER - TY - THES A1 - Kavrakov, Igor T1 - Structural Optimization of Composite Cross-Sections and Elements using Energy Methods N2 - Structural optimization has gained considerable attention in the design of structural engineering structures, especially in the preliminary phase. This study introduces an unconventional approach for structural optimization by utilizing the Energy method with Integral Material Behavior (EIM), based on the Lagrange’s principle of minimum potential energy. An automated two-level optimization search process is proposed, which integrates the EIM, as an alternative method for nonlinear structural analysis, and the bilevel optimization. The proposed procedure secures the equilibrium through minimizing the potential energy on one level, and on a higher level, a design objective function. For this, the most robust strategy of bilevel optimization, the nested method is used. The function of the potential energy is investigated along with its instabilities for physical nonlinear analysis through principle examples, by which the advantages and limitations using this method are reviewed. Furthermore, optimization algorithms are discussed. A numerical fully functional code is developed for nonlinear cross section, element and 2D frame analysis, utilizing different finite elements and is verified against existing EIM programs. As a proof of concept, the method is applied on selected examples using this code on cross section and element level. For the former one a comparison is made with standard procedure, by employing the equilibrium equations within the constrains. The validation of the element level was proven by a theoretical solution of an arch bridge and finally, a truss bridge is optimized. Most of the principle examples are chosen to be adequate for the everyday engineering practice, to demonstrate the effectiveness of the proposed method. This study implies that with further development, this method could become just as competitive as the conventional structural optimization techniques using the Finite Element Method. KW - Strukturoptimierung Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20190815-39593 ER - TY - JOUR A1 - Völker, Conrad A1 - Mämpel, Silvio A1 - Kornadt, Oliver T1 - Measuring the human body’s micro‐climate using a thermal manikin JF - Indoor Air N2 - The human body is surrounded by a micro‐climate which results from its convective release of heat. In this study, the air temperature and flow velocity of this micro‐climate were measured in a climate chamber at various room temperatures, using a thermal manikin simulating the heat release of the human being. Different techniques (Particle Streak Tracking, thermography, anemometry, and thermistors) were used for measurement and visualization. The manikin surface temperature was adjusted to the particular indoor climate based on simulations with a thermoregulation model (UCBerkeley Thermal Comfort Model). We found that generally, the micro‐climate is thinner at the lower part of the torso, but expands going up. At the head, there is a relatively thick thermal layer, which results in an ascending plume above the head. However, the micro‐climate shape strongly depends not only on the body segment, but also on boundary conditions: the higher the temperature difference between the surface temperature of the manikin and the air temperature, the faster the air flow in the micro‐climate. Finally, convective heat transfer coefficients strongly increase with falling room temperature, while radiative heat transfer coefficients decrease. The type of body segment strongly influences the convective heat transfer coefficient, while only minimally influencing the radiative heat transfer coefficient. KW - Raumklima KW - Mikroklima KW - Wärmeübertragung KW - Strömungsmechanik KW - thermal manikin KW - climate chamber KW - micro climate KW - heat transfer coefficient KW - CFD KW - thermography Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20181025-38153 UR - https://onlinelibrary.wiley.com/doi/abs/10.1111/ina.12112 N1 - This is the peer reviewed version of the following article: "Measuring the human body’s micro‐climate using a thermal manikin", which has been published in final form at https://doi.org/10.1111/ina.12112. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. IS - 24, 6 SP - 567 EP - 579 ER - TY - JOUR A1 - Massaretti, Pier Giorgio T1 - Dagli inizi dell’urbanismo teorico alla città moderna. Visioni urbanistiche del totalitarismo – Italia JF - Anthologie zum Städtebau. Das Phänomen Großstadt und die Entstehung der Stadt der Moderne N2 - La prima edizione di questo testo è apparsa, in tedesco, nel volume II.2.: Anthologie zum Städtebau. Das Phänomen Großstadt und die Entstehung der Stadt der Moderne, a cura di Vittorio Magnago Lampugnani, Katia Frey, Eliana Perotti, con il sostegno di Departement Architektur der Eidgenössischen Technischen Hochschule, Zürich (Gebr. Mann Verlag, Berlin 2014, pp. 1307-1390). Previ specifici accordi con l’editore, viene qui presentata la versione originaria, in italiano, dell’intero capitolo: Modernität und Emphase. Städtebau im italienischen Faschismus, e comprendente: i) una capiente saggio introduttivo – in una versione più ampia ed articolata (comprensiva della “Bibliografia sistematica”, di riferimento) del testo in tedesco; ii) la versione in italiano del repertorio antologico di riferimento – e comprensiva di una “Scheda introduttiva”, sull’Autore-Opera, e di una selezione del testo in esame. KW - Städtebau Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20170529-32228 SP - 1 EP - 45 ER - TY - CHAP A1 - Massaretti, Pier Giorgio T1 - La ri-fondazione della Libia balbiana (1933-1939). Il poderoso racconto fotografico dei “Ventimila” T2 - Città mediterranee in trasformazione N2 - La prima edizione di questo testo è apparsa negli atti del VI Convegno Internazionale di Studi del CIRICE – Centro Interdipartimentale di Ricerca sull’Iconografia della Città Europea − Università di Napoli Federico II, (Napoli, 13-15 marzo 2014), dal titolo: Città mediterranee in trasformazione. Identità e immagine del paesaggio urbano tra Sette e Novecento, a cura di A. Buccaro e C. de Seta (Collana: Polis, 6; Napoli: Edizioni Scientifiche Italiane, 2014; pp. 1216; ISBN 9788849528145), all’interno della sessione 7, Le trasformazioni del paesaggio urbano nella fotografia e nella cinematografia, coordinatori: F. Capano, M. Iuliano, pp. 1085-1098. Il Convegno, aperto a studiosi di ambito nazionale e internazionale, si poneva l’obiettivo di fare il punto sulla storiografia riguardante la città mediterranea in età contemporanea, con particolare riferimento alla sua identità, struttura e immagine, dall’inizio dell’industrializzazione all’età post-illuminista e borghese, fino ai temi inerenti l’evoluzione/involuzione del territorio e del paesaggio post-industriale, nonché lo sviluppo del modello turistico tra Otto e Novecento. KW - Städtebau Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20170529-32234 ER - TY - JOUR A1 - Zhuang, Xiaoying A1 - Huang, Runqiu A1 - Liang, Chao A1 - Rabczuk, Timon T1 - A coupled thermo-hydro-mechanical model of jointed hard rock for compressed air energy storage JF - Mathematical Problems in Engineering N2 - Renewable energy resources such as wind and solar are intermittent, which causes instability when being connected to utility grid of electricity. Compressed air energy storage (CAES) provides an economic and technical viable solution to this problem by utilizing subsurface rock cavern to store the electricity generated by renewable energy in the form of compressed air. Though CAES has been used for over three decades, it is only restricted to salt rock or aquifers for air tightness reason. In this paper, the technical feasibility of utilizing hard rock for CAES is investigated by using a coupled thermo-hydro-mechanical (THM) modelling of nonisothermal gas flow. Governing equations are derived from the rules of energy balance, mass balance, and static equilibrium. Cyclic volumetric mass source and heat source models are applied to simulate the gas injection and production. Evaluation is carried out for intact rock and rock with discrete crack, respectively. In both cases, the heat and pressure losses using air mass control and supplementary air injection are compared. KW - Energiespeicherung KW - Druckluft KW - Kaverne KW - Modellierung Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20170428-31726 ER - TY - JOUR A1 - Völske, Michael A1 - Gollub, Tim A1 - Hagen, Matthias A1 - Stein, Benno T1 - A keyquery-based classification system for CORE JF - D-Lib Magazine N2 - We apply keyquery-based taxonomy composition to compute a classification system for the CORE dataset, a shared crawl of about 850,000 scientific papers. Keyquery-based taxonomy composition can be understood as a two-phase hierarchical document clustering technique that utilizes search queries as cluster labels: In a first phase, the document collection is indexed by a reference search engine, and the documents are tagged with the search queries they are relevant—for their so-called keyqueries. In a second phase, a hierarchical clustering is formed from the keyqueries within an iterative process. We use the explicit topic model ESA as document retrieval model in order to index the CORE dataset in the reference search engine. Under the ESA retrieval model, documents are represented as vectors of similarities to Wikipedia articles; a methodology proven to be advantageous for text categorization tasks. Our paper presents the generated taxonomy and reports on quantitative properties such as document coverage and processing requirements. KW - Massendaten KW - Taxonomie KW - Dynamic Taxonomy Composition, Keyquery, Classification Systems, Reverted Index, Big Data Problem Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20170426-31662 ER - TY - JOUR A1 - Nagel, Falk A1 - Simon, Flaviu A1 - Kümmel, Benjamin A1 - Bergmann, Jean Pierre A1 - Hildebrand, Jörg T1 - Optimization Strategies for Laser Welding High Alloy Steel Sheets JF - Physics Procedia N2 - A known phenomenon during laser welding of thin sheets is the deformation caused by thermally induced stresses. This deformation can result in a change of the gap width between the welded parts, which leads to an unstable welding process. Inducing displacements by using a second heat source will compensate for the change in gap width, hence optimizing the welding process. The base material is 1 mm thick austenitic stainless steel 1.4301, which is welded by a CO2 laser. The second heat source is a diode laser. The gap between the welded parts was set between 0.05 mm and 0.1 mm. The influence of the second heat source on the welding process and the welding result is described. The usage of a second heat source allows a higher gap width to be set prior to the welding process. The results of the numerical simulation were found to be corresponding to those of the experiments. KW - Edelstahl KW - Laserschweißen KW - Laser Welding; CO2; Diode; Distortion; Finite Element Analysis; Thermal Analysis; Mechanical Analysis; Numerical Model Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20170425-31554 SP - 1242 EP - 1251 ER - TY - JOUR A1 - Motra, Hem Bahadur A1 - Hildebrand, Jörg A1 - Dimmig-Osburg, Andrea T1 - Assessment of strain measurement techniques to characterise mechanical properties of structural steel JF - Engineering Science and Technology, an International Journal N2 - Strain measurement is important in mechanical testing. A wide variety of techniques exists for measuring strain in the tensile test; namely the strain gauge, extensometer, stress and strain determined by machine crosshead motion, Geometric Moire technique, optical strain measurement techniques and others. Each technique has its own advantages and disadvantages. The purpose of this study is to quantitatively compare the strain measurement techniques. To carry out the tensile test experiments for S 235, sixty samples were cut from the web of the I-profile in longitudinal and transverse directions in four different dimensions. The geometry of samples are analysed by 3D scanner and vernier caliper. In addition, the strain values were determined by using strain gauge, extensometer and machine crosshead motion. Three techniques of strain measurement are compared in quantitative manner based on the calculation of mechanical properties (modulus of elasticity, yield strength, tensile strength, percentage elongation at maximum force) of structural steel. A statistical information was used for evaluating the results. It is seen that the extensometer and strain gauge provided reliable data, however the extensometer offers several advantages over the strain gauge and crosshead motion for testing structural steel in tension. Furthermore, estimation of measurement uncertainty is presented for the basic material parameters extracted through strain measurement. KW - Baustahl KW - Werkstoffprüfung KW - Zugversuch KW - Affecting factors; Measurement uncertainty; Materials testing; Quantitative comparison; Strain comparison; Tensile test Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20170425-31540 SP - 260 EP - 269 ER - TY - JOUR A1 - Masood, R. A1 - Kharal, M. K. N. A1 - Nasir, A.R. T1 - Is BIM Adoption Advantageous for Construction Industry of Pakistan? JF - Procedia Engineering N2 - Lack of Information technology applications on construction projects lead to complex flow of data during project life cycle. Building Information Modeling (BIM) has gained attention in the Architectural, Engineering and Construction (AEC) industry, envisage the use of virtual n-dimensional (n-D) models to identify potential conflicts in design, construction or operational of any facility. A questionnaire has been designed to investigate perceptions regarding BIM advantages. Around 102 valid responses received from diversified stakeholders. Results showed very low BIM adoption with low level of ‘Buzz’. BIM is a faster and more effective method for designing and construction management, it improves quality of the design and construction and reduces rework during construction; which came out as the top thee advantages according to the perception of AEC professionals of Pakistan.BIM has least impact on reduction of cost, time and human resources. This research is a bench mark study to understand adoption and advantageous of BIM in Pakistan Construction Industry. KW - Building Information Modeling KW - Bauindustrie KW - Pakistan KW - BIM, BIM Adoption, BIM Advantages , Construction Industry, Pakistan Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20170425-31509 SP - 229 EP - 238 ER - TY - JOUR A1 - Linnow, Kirsten A1 - Niermann, Michael A1 - Bonatz, Dennis A1 - Posern, Konrad A1 - Steiger, Michael T1 - Experimental Studies of the Mechanism and Kinetics of Hydration Reactions JF - Energy Procedia N2 - The mechanism and the kinetics of hydration reactions are important for the application of a salt hydrate as a thermochemical heat storage material. MgSO4·H2O and Na2SO4 were chosen in this study because they are both promising candidates for such an application. Considering that the hydration of these salts yields MgSO4·7H2O and Na2SO4·10H2O as the reaction products, the maximum overall heat effect can be calculated from the heat of condensation of water vapor (44 kJ mol–1) and the heats of hydration of 75 kJ·mol-1 (for MgSO4·H2O) and 81 kJ mol-1 (for Na2SO4). Based on the densities of the two hydrated phases, this results in the very high theoretical energy densities of 2.3 GJ·m-3 and 2.4 GJ·m-3, respectively, for MgSO4·7H2O and Na2SO4·10H2O. Not only the energy density is important for the dimensioning of a storage system, but also the kinetics of hydration reactions play a major role for the application as storage material. In the present study, hydration reactions under varying climatic conditions were investigated by using water vapor sorption measurements and in-situ Raman microscopy. Using the phase diagrams, it can be clearly shown that the mechanism and the kinetics depend on the climatic conditions. Below the deliquescence humidity of the lower hydrated phase the hydration proceeds as solid state reaction, whilst above the deliquescence humidity a through solution mechanism takes place. KW - Wärmespeicherung KW - Hydratation KW - Magnesiumsulfat KW - Natriumsulfat KW - hermochemical heat storage, hydration mechanism, magnesium sulfate; sodium sulfate Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20170425-31484 SP - 394 EP - 404 ER - TY - JOUR A1 - Le, Ha Thanh A1 - Nguyen, Sang Thanh A1 - Ludwig, Horst-Michael T1 - A Study on High Performance Fine-Grained Concrete Containing Rice Husk Ash JF - International Journal of Concrete Structures and Materials N2 - Rice husk ash (RHA) is classified as a highly reactive pozzolan. It has a very high silica content similar to that of silica fume (SF). Using less-expensive and locally available RHA as a mineral admixture in concrete brings ample benefits to the costs, the technical properties of concrete as well as to the environment. An experimental study of the effect of RHA blending on workability, strength and durability of high performance fine-grained concrete (HPFGC) is presented. The results show that the addition of RHA to HPFGC improved significantly compressive strength, splitting tensile strength and chloride penetration resistance. Interestingly, the ratio of compressive strength to splitting tensile strength of HPFGC was lower than that of ordinary concrete, especially for the concrete made with 20 % RHA. Compressive strength and splitting tensile strength of HPFGC containing RHA was similar and slightly higher, respectively, than for HPFGC containing SF. Chloride penetration resistance of HPFGC containing 10–15 % RHA was comparable with that of HPFGC containing 10 % SF. KW - Hochfester Beton KW - Verarbeitungseigenschaft KW - Druckfestigkeit KW - high performance fine-grained concrete, rice husk ash, workability, compressive strength, splitting tensile strength, chloride penetration resistance Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20170425-31477 SP - 301 EP - 307 ER - TY - JOUR A1 - Ataollahi Oshkour, Azim A1 - Talebi, Hossein A1 - Seyed Shirazi, Seyed Farid A1 - Bayat, Mehdi A1 - Yau, Yat Huang A1 - Tarlochan, Faris A1 - Abu Osman, Noor Azuan T1 - Comparison of various functionally graded femoral prostheses by finite element analysis JF - Scientific World Journal N2 - This study is focused on finite element analysis of a model comprising femur into which a femoral component of a total hip replacement was implanted. The considered prosthesis is fabricated from a functionally graded material (FGM) comprising a layer of a titanium alloy bonded to a layer of hydroxyapatite. The elastic modulus of the FGM was adjusted in the radial, longitudinal, and longitudinal-radial directions by altering the volume fraction gradient exponent. Four cases were studied, involving two different methods of anchoring the prosthesis to the spongy bone and two cases of applied loading. The results revealed that the FG prostheses provoked more SED to the bone. The FG prostheses carried less stress, while more stress was induced to the bone and cement. Meanwhile, less shear interface stress was stimulated to the prosthesis-bone interface in the noncemented FG prostheses. The cement-bone interface carried more stress compared to the prosthesis-cement interface. Stair climbing induced more harmful effects to the implanted femur components compared to the normal walking by causing more stress. Therefore, stress shielding, developed stresses, and interface stresses in the THR components could be adjusted through the controlling stiffness of the FG prosthesis by managing volume fraction gradient exponent. KW - Finite-Elemente-Methode KW - Hüftgelenk KW - Funktioneller Gradientenwerkstoff Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20170413-31194 ER - TY - JOUR A1 - Amani, Jafar A1 - Saboor Bagherzadeh, Amir A1 - Rabczuk, Timon T1 - Error estimate and adaptive refinement in mixed discrete least squares meshless method JF - Mathematical Problems in Engineering N2 - The node moving and multistage node enrichment adaptive refinement procedures are extended in mixed discrete least squares meshless (MDLSM) method for efficient analysis of elasticity problems. In the formulation of MDLSM method, mixed formulation is accepted to avoid second-order differentiation of shape functions and to obtain displacements and stresses simultaneously. In the refinement procedures, a robust error estimator based on the value of the least square residuals functional of the governing differential equations and its boundaries at nodal points is used which is inherently available from the MDLSM formulation and can efficiently identify the zones with higher numerical errors. The results are compared with the refinement procedures in the irreducible formulation of discrete least squares meshless (DLSM) method and show the accuracy and efficiency of the proposed procedures. Also, the comparison of the error norms and convergence rate show the fidelity of the proposed adaptive refinement procedures in the MDLSM method. KW - Elastizität KW - Fehlerabschätzung KW - MDLSM method Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20170413-31181 ER - TY - JOUR A1 - Adamatzky, Andrew A1 - Schubert, Theresa T1 - Slime mold microfluidic logical gates JF - Materials Today N2 - We demonstrate how logical operations can be implemented in ensembles of protoplasmic tubes of acellular slime mold Physarum polycephalum. The tactile response of the protoplasmic tubes is used to actuate analogs of two- and four-input logical gates and memory devices. The slime mold tube logical gates display results of logical operations by blocking flow in mechanically stimulated tube fragments and redirecting the flow to output tube fragments. We demonstrate how XOR and NOR gates are constructed. We also exemplify circuits of hybrid gates and a memory device. The slime mold based gates are non-electronic, simple and inexpensive, and several gates can be realized simultaneously at sites where protoplasmic tubes merge. KW - Physarum polycephalum KW - protoplasmic tubes, Nucleolus-Organisator-Region Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20170413-31168 SP - 86 EP - 91 ER - TY - RPRT A1 - König, Reinhard A1 - Tapias, Estefania A1 - Schmitt, Gerhard T1 - New Methods in Urban Analysis and Simulation: Documentation of the teaching results from the spring semester 2014 N2 - Documentation of the teaching results from the spring semester 2014 at ETH Zurich KW - Städtebau Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20160121-25154 ER -