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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Effect of diaphragm wall construction on adjacent deep foundation

Mohamed, Ahmed Abdallah Elhashemy Zaki 08 March 2017 (has links) (PDF)
The need of using the underground space was limited in the human history, but in the last century and due to the increase of world population, the use of the underground space has become essential. Underground metro stations, deep garages, tunnels and basements, etc... are examples of using the underground space inside the cities. The use of underground space is conducted through deep excavation or tunneling. Several techniques are used to conduct the deep excavation and one of the most popular and well known techniques used for deep excavation is the diaphragm walling technique which is widely used specially inside the cities to safe space because it requires a very small space to conduct a deep reinforced concreted wall under the ground. However, the construction of such walls causes deformation of the surrounding ground and it could also affect the nearby existing structures. In some recorded cases the slurry trench failed and causes a great deformation which effect the nearby structures. However, Minor damages and cracks were observed in buildings near stable slurry trenches, because the soil deformation was high. The existing structures inside the cities have been constructed on shallow or deep foundations and this research was oriented to study the effect of diaphragm wall installation on the existing adjacent piled foundation. Very limited studies were made to investigate such an effect. At Cambridge university centrifuge model tests were conducted to investigate the effect of slurry reduction on single piles. Field observation was conducted in several projects and showed the settlement and deformation of buildings located on deep foundation during the diaphragm wall trenching. Numerical analysis was conducted using FLAC 3D to simulate the laboratory and the available field works. FLAC 3D is a commercial software and it depend in its analysis on finite difference method. The purpose of the simulation was to verify the used numerical analysis method. The results from the numerical analysis were in a good agreement with the available field data results, and they were also in good agreement with the laboratory test results regarding soil settlement but it was not in such good agreement when they were compared regarding the pile. Generally, from the verification the numerical analysis method is considered to be reliable. A parametric study was performed using the verified numerical analysis method. The flexible nature of the numerical analysis allows to simulate different cases and to study a variety of parameters. The output of the parametric study was the pile deflection, the bending moment and the shaft friction. The study was divided into three main parts while each part contains several parameter combinations. The first part studied the effect of the single and double panel(s) on the single pile group that has different piles numbers and formations. The second and third parts studied the effect of multiple panels on connected pile groups and piled raft foundation, respectively. Generally, the studied parameters can be divided into three main groups. The first is related to the trench which includes the panel dimension, the number of panels and the slurry level inside the panel. The effect of slurry pressure reduction at some levels inside the trench was also studied. The second group concerned the soil type and ground water level. The third group is related to the deep foundation which includes pile characteristics, location, and formation within the group. The results from the parametric study showed that the pile behavior was greatly affected by panel length, groundwater level, slurry level inside the trench and steadiness of the slurry pressure. The piles were also affected by the different stages of construction related to the pile location from the constructed panel. The piles within the group act together so they behave different from each other according to their position. The effect of the pile on the trench stability is presented through a simple analytical approach which is based on the wedge analysis. The analytical approach provided equations that calculate the factor of safety in two and three dimensions. The pile location was governing the equation that calculate the factor of safety because the pile could be fully inside the failure wedge or intersect with the failure surface. A comparative study was conducted to find out the effect of the different pile location and other parameters on the safety factor. Generally, this comparative study showed that the pile located within the failure wedge reduces the factor of safety, while the pile that intersects the failure surface could increase it. The pile row near a trench that contains piles inside the failure wedge and others intersects the failure surface act together to balance the failure wedge. The factor of safety results of some cases from the analytical approach were also compared with those calculated from the numerical analysis. In general, the factor of safety from the numerical analysis was higher than that calculated from the proposed analytical approach. This research helped to understand the trenching effect on the ground surface and on the nearby piled foundations. It provided charts that could help to predict the soil deformation and earth pressure coefficient which could be used in the design. It showed through the parametric study the precautions that should be taken into consideration during trenching process near piled foundation. This research provided a design method for the slurry trench panel near piled foundation.
2

Networks of Entrepreneurs Revisited. Dilemmatic Settings and Dysfunctional Effects during Company Foundation Processes

Fried, Andrea, Knoll, Michael, Duschek, Sigrid 06 August 2006 (has links) (PDF)
Many entrepreneurial research studies underline implicitly the positive evidence of a connection between the economic success and networks. However, any social relationship which an entrepreneur maintains does not necessarily have positive effects and consequently does not represent a capital to the new established organization. Dysfunctional effects result from the circumstance that the different actors have different, sometimes contrary requirements on networks. The aim of our article is to explore dilemmatic constellations within networks and to enable entrepreneurial founders or consultants to face the related challenges.
3

Generative Incubators

Roth, Steffen, Vordank, Tino 13 February 2007 (has links)
Starting the own business is sometimes a dream sometimes a nightmare but undoubtedly from a macro-economic perspective it is considered to be a promising concept to secure long-term economic growth and society’s welfare, at least in Germany. Strong efforts were made to support start ups and potential entrepreneurs to run their own business. A plethora of programs were launched which were supposed to facilitate the start up process – but reality is disenchanting: The published data in the 2004 GEM indicate that the idea of an entrepreneurial society in Germany is still far beyond its realization. Germany ranks 17th out of 31 GEM states in terms of “nascent entrepreneurs” and only 22nd regarding the “young entrepreneurs”. Compared to other GEM countries the German adults are considered to be more pessimistic in terms of entrepreneurial issues: The chances of establishing a successful business are evaluated lower than the years before. On the other hand the context factors which are considered to influence the start up opportunities especially in terms of governmental support and physical infrastructure were evaluated to be one of the best. Especially concerning the latter aspect strong efforts have been made to support entrepreneurs. In this context, and maybe because of - A “… post-1970s fascination with ‘high-tech’ regions worldwide” (Cooke/Leydesdorff 2006: 9), - A continuous liberalization of the world market and its impact on national production systems (which is well discussed in the context of the conversion of cooperatives), or - The dawn of the concept of national innovations systems (e.g. Lundvall 1988; Cozzens et al. 1990), For more than two decades, one promising concept of sustaining entrepreneurs was seen in the idea of incubators1 which mainly offer support in terms of infrastructure and funding opportunities. Meantime, we observe that questions emerge of how effective and efficient incubators work as one major instrument of macroentrepreneurial (Van de Veen 1995, Chiles/Meyer 2001) activities in order to facilitate start ups and to support the first steps of a new business from its start to its growth. The value of the incubator model as an effective means of technology and knowledge transfer especially from universities is continually discussed and questioned (Cunningham 1999). For example, a study run by Allen and Kahman (1985) concluded that incubators are tools for developing enterprises which create a positive environment for small businesses to succeed. Indeed, lots of studies brought up that incubators are an efficient and effective way to sustain spin-out processes and to contribute to regional development and prosperity. However, on the other hand some shortcomings are obvious: Finer and Holberton (2000) take into question the incubator model because it takes the initiative away from the start-up team. The paper refers to these observations. We assume by means of some international empirical studies that the functions of incubators are enhanced as a result of a (evolutional) learning process. On this basis we derive hypothesis about the dealing with the upcoming challenges and provide further research questions in an explorative way. Paragraph 2 introduces a three phased model of business incubators and classifies existing incubators. It will be obvious, that there is an increasing amount of functions that are allocated by incubators. Within paragraph 3 we examine recent developments from a macroeconomic perspective and contrast to this the evolution of incubators. Paragraph 4 presents two types of incubators that take these
4

Validierung eines hochzyklischen Akkumulationsmodells anhand von Modellversuchen an Monopiles mit einer großen Anzahl an Belastungszyklen

Satubach, Patrick, Machaček, J., Wichtmann, T. 21 July 2020 (has links)
The high-cycle accumulation (HCA) model of Niemunis et al. is applied for the simulation of model tests on monopiles subjected to high-cyclic loading with up to five million loading cycles. A new finite element program for geotechnical applications written by the authors is used for this purpose. The simulations with the HCA model show a good agreement with the deformations measured in the model tests.
5

Untersuchungen zum dynamischen Verhalten schwimmender Offshoregründungen

Adam, Frank 20 May 2015 (has links) (PDF)
Durch Umwandlung unterschiedlichster Formen von Energie in mechanische oder elektrische Energie wird die Menschheit seit Jahrhunderten bei der Umsetzung von Arbeitsprozessen im Alltag und bei der industriellen Nutzung unterstützt. Strömende Medien wie Wasser oder Wind gelten dabei als die ältesten Energielieferanten. Im Rahmen der Dissertation wird das Konzept einer zugspannungsverankerten Plattform für Offshore Windenergieanlagen (WEA) vorgestellt, wobei neben den, für diesen Plattformtyp typischen, vertikalen auch geneigte Verankerungselemente Verwendung finden. Diese Art der Verspannung einer zugspannungsverankerten Plattform, respektive ’Tension Leg Platfrom’ (TLP) ist bisher von keiner Quelle bekannt und stellt ein Alleinstellungsmerkmal dar. Folglich sollen Untersuchungen zum dynamischen Verhalten schwimmender Gründungen für Offshore WEA, im Speziellen zu einer TLP mit vertikalen und geneigten Ankerelementen, im Rahmen dieser Arbeit erstmalig vorgestellt werden. Die Plattform ist ein modular gestaltetes Tragwerk bestehend aus großen Rohren und mit integrierten zylindrischen Auftriebskörpern. Diese erzeugen im Transportzustand der Plattform vom Hafen zum Einsatzort und im Betriebszustand innerhalb eines Windparks den nötigen Auftrieb. Infolge der speziellen Art der Verspannung werden die Bewegungen der TLP durch die, aus den Belastungen resultierenden, Seildehnungen dominiert. Damit stellte die TLP im Vergleich zu anderen schwimmenden Gründungen ein bewegungsarmes System dar. Inhalt der hier vorgelegten Arbeit sind Untersuchungen zum dynamischen Verhalten schwimmender Offshoregründungen, im speziellen einer TLP für Windenergieanlagen. Es wurden unterschiedliche Tragstrukturen für TLP-Systeme entwickelt und im Rahmen von Modellversuchen getestet. Den Kern der Arbeit bildet der Vergleich des dynamischen Tragverhaltens der unterschiedlichen Plattformen unter Berücksichtigung der geometrischen und strukturellen Randbedingungen.
6

Untersuchungen zum dynamischen Verhalten schwimmender Offshoregründungen

Adam, Frank 31 March 2015 (has links)
Durch Umwandlung unterschiedlichster Formen von Energie in mechanische oder elektrische Energie wird die Menschheit seit Jahrhunderten bei der Umsetzung von Arbeitsprozessen im Alltag und bei der industriellen Nutzung unterstützt. Strömende Medien wie Wasser oder Wind gelten dabei als die ältesten Energielieferanten. Im Rahmen der Dissertation wird das Konzept einer zugspannungsverankerten Plattform für Offshore Windenergieanlagen (WEA) vorgestellt, wobei neben den, für diesen Plattformtyp typischen, vertikalen auch geneigte Verankerungselemente Verwendung finden. Diese Art der Verspannung einer zugspannungsverankerten Plattform, respektive ’Tension Leg Platfrom’ (TLP) ist bisher von keiner Quelle bekannt und stellt ein Alleinstellungsmerkmal dar. Folglich sollen Untersuchungen zum dynamischen Verhalten schwimmender Gründungen für Offshore WEA, im Speziellen zu einer TLP mit vertikalen und geneigten Ankerelementen, im Rahmen dieser Arbeit erstmalig vorgestellt werden. Die Plattform ist ein modular gestaltetes Tragwerk bestehend aus großen Rohren und mit integrierten zylindrischen Auftriebskörpern. Diese erzeugen im Transportzustand der Plattform vom Hafen zum Einsatzort und im Betriebszustand innerhalb eines Windparks den nötigen Auftrieb. Infolge der speziellen Art der Verspannung werden die Bewegungen der TLP durch die, aus den Belastungen resultierenden, Seildehnungen dominiert. Damit stellte die TLP im Vergleich zu anderen schwimmenden Gründungen ein bewegungsarmes System dar. Inhalt der hier vorgelegten Arbeit sind Untersuchungen zum dynamischen Verhalten schwimmender Offshoregründungen, im speziellen einer TLP für Windenergieanlagen. Es wurden unterschiedliche Tragstrukturen für TLP-Systeme entwickelt und im Rahmen von Modellversuchen getestet. Den Kern der Arbeit bildet der Vergleich des dynamischen Tragverhaltens der unterschiedlichen Plattformen unter Berücksichtigung der geometrischen und strukturellen Randbedingungen.
7

Editorial Herbst 2017

29 July 2019 (has links)
No description available.
8

Goobi wird Verein

Bonte, Achim 08 January 2013 (has links) (PDF)
Mit der Gründung des Vereins „Goobi. Digitalisieren im Verein“ am 17. September 2012 hat das Wort „Goobi“ eine weitere Bedeutung erhalten. Goobi ist die verbreitetste Open Source-Software zur Produktion und Präsentation von Digitalisaten. Sie ist Markenzeichen für Plattformunabhängigkeit, Modularität, Mandantenfähigkeit, offene Schnittstellen und internationale Standards. Sie steht für umfassende Lösungen zur Boutique- und Massendigitalisierung sowie skalierbare Unterstützungsleistungen durch namhafte Firmen; und seit einigen Wochen ist Goobi nun also auch ein eingetragener Verein mit anerkannter Gemeinnützigkeit. [...]
9

Bestimmungsgründe von Existenzgründungen im Handwerk unter besonderer Berücksichtigung des sozioökonomischen Ansatzes / Basic conditions for start-ups in the crafts sector under consideration of the socioeconomic approach

Heyden, Maribel 08 July 2002 (has links)
No description available.
10

Literaturforum Bibliothek – Autoren aus Sachsen in sächsischen Bibliotheken

Tröml, Sibille, Palisch, Lucie 16 July 2014 (has links) (PDF)
Literatur wird gemeinhin als „geistige Nahrung“ erachtet. Doch bekanntlich gilt nicht nur der Prophet, sondern auch der Dichter im eigenen Land nicht immer viel. Im Mittelpunkt unserer Bemühungen um Fördermittel und bei der Planung des Projektes „Literaturforum Bibliothek – Autoren aus Sachsen in sächsischen Bibliotheken“ stand nd steht daher für uns, den Sächsischen Literaturrat e.V., die Gesamtheit der in Sachsen lebenden oder von hier stammenden Autoren und Übersetzer. Sie sind es, denen wir als sächsischer Landesdachverband für Literatur ein Podium bieten möchten, denn häufig geraten sie bei mehr als 90.000 Neuerscheinungen pro Jahr gerade auch in Sachsen aus dem Blick.

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