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1.
Beylat, Delphine.
Contribution à l'étude du comportement dynamique aléatoire de structures libres et empilées sous séïsme : Contribution to the study of the random dynamic behaviour of free-standing flexible stacked structures under seismic excitation.
Degree: Docteur es, Matériaux et Génie Mécanique, 2020, Université Clermont Auvergne (2017-2020)
URL: http://www.theses.fr/2020CLFAC041 
► La stabilité des structures libres sous séismes est une question majeure dans l’évaluation de la sûreté des installations industrielles. Dans ces installations, certains équipements peuvent,…
(more)
▼ La stabilité des structures libres sous séismes est une question majeure dans l’évaluation de la sûreté des installations industrielles. Dans ces installations, certains équipements peuvent, en effet, ne pas être ancrés au sol, notamment dans les halls d’entreposage, ou être désolidarisés du sol le temps d’une opération de maintenance. Lors d’un séisme ces structures libres sont susceptibles de se renverser, de glisser, ou dans les cas les plus graves, de devenir des objets dits "missiles"pouvant blesser des personnes ou détériorer des équipements importants pour la sûreté lors d’un impact. Dans cette thèse, la
structure libre étudiée est une
structure industrielle représentant un empilement de trois paniers libres destinés au stockage de colis. La sensibilité inhérente au comportement non linéaire de telles structures, qui implique chocs et glissements, est une difficulté importante qui a pour conséquence que la démonstration de sûreté ne peut être envisagée que sous l’angle d’une approche probabiliste, essentiellement basée sur des calculs dynamiques temporels non linéaires. Pour ce faire, un premier modèle simplifié semi-analytique a été développé en s’inspirant de travaux récents de la littérature. Il permet d’obtenir une estimation rapide et globale de la réponse sismique de l’empilement en tenant compte des principaux phénomènes physiques qui se produisent sous une excitation unidirectionnelle.Pour obtenir plus de précision sur la réponse sismique de l’empilement, différents modèles « éléments finis » ont également été développés et une importante campagne expérimentale a été mise en oeuvre sur la table vibrante unidirectionnelle Vésuve du laboratoire EMSI du CEA de Saclay pour : (1) valider et calibrer, le cas échéant, les modèles numériques (analyses modale et sismique)et (2) évaluer la variabilité des réponses sismiques de la
structure, à la fois d’un point de vue expérimental et numérique.Les deux approches -numérique et expérimentale- couplées à une approche fiabiliste, ont été menées de front pendant cette thèse et ont permis de mettre en évidence plusieurs phénomènes.D’un point de vue déterministe, les conséquences du soulèvement de la base de l’empilement sur son comportement global ont été identifiées. Il s’agit typiquement de l’augmentation de sa fréquence apparente lorsque la base se soulève, cette fréquence correspondant à la fréquence du« mode fondamental » pour lequel la base est en rotation autour de l’un de ses points d’appui.Ce travail a également montré que l’ajustement des propriétés dynamiques des modèles est une tâche essentielle, mais délicate, pour obtenir une réponse non linéaire satisfaisante. En pratique,cela signifie qu’il est difficile de connaître a priori quelles sont ces propriétés dynamiques. Néanmoins,le modèle semi-analytique peut être une alternative pour évaluer rapidement la sensibilité des modèles par rapport aux principaux paramètres physiques, bien que, dans l’absolu, cette sensibilité puisse ne pas être du même ordre d’importance d’un modèle à l’autre.De plus, comme cela…
Advisors/Committee Members: Fogli, Michel (thesis director).
Subjects/Keywords: Structures libres; Structures flexibles; Séismes; Empilements; Basculements; Glissements; Analyse probabiliste; Sûreté; Fiabilité; Free standing structure; Flexible structure; Seismic; Stacked structure; Rocking; Sliding; Probabilistic analysis; Risk assessment studies; Reliability
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APA (6th Edition):
Beylat, D. (2020). Contribution à l'étude du comportement dynamique aléatoire de structures libres et empilées sous séïsme : Contribution to the study of the random dynamic behaviour of free-standing flexible stacked structures under seismic excitation. (Doctoral Dissertation). Université Clermont Auvergne (2017-2020). Retrieved from http://www.theses.fr/2020CLFAC041
Chicago Manual of Style (16th Edition):
Beylat, Delphine. “Contribution à l'étude du comportement dynamique aléatoire de structures libres et empilées sous séïsme : Contribution to the study of the random dynamic behaviour of free-standing flexible stacked structures under seismic excitation.” 2020. Doctoral Dissertation, Université Clermont Auvergne (2017-2020). Accessed April 17, 2021.
http://www.theses.fr/2020CLFAC041.
MLA Handbook (7th Edition):
Beylat, Delphine. “Contribution à l'étude du comportement dynamique aléatoire de structures libres et empilées sous séïsme : Contribution to the study of the random dynamic behaviour of free-standing flexible stacked structures under seismic excitation.” 2020. Web. 17 Apr 2021.
Vancouver:
Beylat D. Contribution à l'étude du comportement dynamique aléatoire de structures libres et empilées sous séïsme : Contribution to the study of the random dynamic behaviour of free-standing flexible stacked structures under seismic excitation. [Internet] [Doctoral dissertation]. Université Clermont Auvergne (2017-2020); 2020. [cited 2021 Apr 17].
Available from: http://www.theses.fr/2020CLFAC041.
Council of Science Editors:
Beylat D. Contribution à l'étude du comportement dynamique aléatoire de structures libres et empilées sous séïsme : Contribution to the study of the random dynamic behaviour of free-standing flexible stacked structures under seismic excitation. [Doctoral Dissertation]. Université Clermont Auvergne (2017-2020); 2020. Available from: http://www.theses.fr/2020CLFAC041
2.
Alkan, Can.
Computational Studies on Evolution and Functionality of
Genomic Repeats.
Degree: PhD, Computing and Information Science, 2005, Case Western Reserve University School of Graduate Studies
URL: http://rave.ohiolink.edu/etdc/view?acc_num=case1120143436
► Human DNA consists of a large number of repeat sequences. The repeat sequences can be in the form of tandem repeats and interspersed repeats and…
(more)
▼ Human DNA consists of a large number of repeat
sequences. The repeat sequences can be in the form of tandem
repeats and interspersed repeats and cover more than 60% of the
human genome sequence. Segmental repeats are a result of
duplication events that have occurred during the evolution of human
genome. This dissertation presents an algorithmic and computational
study of the repeat sequences with emphasis on the identification
of the location and order of duplication events as well as the
identification of the responsible cellular mechanisms. A
complementary goal of this work is to study the effect of the
repeat sequences to gene regulation. Thus it provides a
comprehensive study of the evolution and function of repeat
sequences in the human genome. The primary example of tandem repeat
sequences in the human genome are the centromeric alpha-satellite
DNA that consists of arbitrary monomer pairs of size approximately
171bp. Although it is possible that alpha-satellite sequences
developed as a result of subsequent unequal crossovers only, no
formal computational framework had been developed to verify this
possibility. This thesis includes such a framework and reports on
experiments which imply that pericentromeric alpha-satellite
segments are evolutionarily distinct from the higher-order repeat
segments. Certain repeat sequences are not only interesting for
evolutionary studies but also have essential functional properties.
Recent studies demonstrate the existence of special antisense RNAs
used in post-transcriptional gene regulation through binding with
duplicate target sequences in the mRNA. These RNAs are known to be
synthesized naturally to control gene expression in C.elegans,
Drosophila and other organisms, or regulate plasmid copy numbers in
E.coli; they have also been artificially constructed to knock-out
genes of interest in humans and other organisms in order to find
out their functions as well as for other purposes. Several
computational methods can be used to predict the secondary
structure of a single RNA molecule, but no such algorithm exists
for reliably predicting the joint secondary
structure of two
interacting RNA molecules, or measuring the stability of such a
joint
structure. This dissertation presents a combinatorial
approach for solving the RNA-RNA interaction prediction problem
between an antisense RNA and its target mRNA. Three main models for
joint
structure prediction are introduced, and the proposed methods
are applied to discover targets for any given antisense RNA in
whole genomic and plasmid sequences.
Advisors/Committee Members: Sahinalp, S. Cenk (Advisor).
Subjects/Keywords: Computer Science; Joint Structure; monomers; RNA; Stacked Pair; Alpha-Satellite; Energy Models; Pair Energy
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APA ·
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CSE |
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Manager
APA (6th Edition):
Alkan, C. (2005). Computational Studies on Evolution and Functionality of
Genomic Repeats. (Doctoral Dissertation). Case Western Reserve University School of Graduate Studies. Retrieved from http://rave.ohiolink.edu/etdc/view?acc_num=case1120143436
Chicago Manual of Style (16th Edition):
Alkan, Can. “Computational Studies on Evolution and Functionality of
Genomic Repeats.” 2005. Doctoral Dissertation, Case Western Reserve University School of Graduate Studies. Accessed April 17, 2021.
http://rave.ohiolink.edu/etdc/view?acc_num=case1120143436.
MLA Handbook (7th Edition):
Alkan, Can. “Computational Studies on Evolution and Functionality of
Genomic Repeats.” 2005. Web. 17 Apr 2021.
Vancouver:
Alkan C. Computational Studies on Evolution and Functionality of
Genomic Repeats. [Internet] [Doctoral dissertation]. Case Western Reserve University School of Graduate Studies; 2005. [cited 2021 Apr 17].
Available from: http://rave.ohiolink.edu/etdc/view?acc_num=case1120143436.
Council of Science Editors:
Alkan C. Computational Studies on Evolution and Functionality of
Genomic Repeats. [Doctoral Dissertation]. Case Western Reserve University School of Graduate Studies; 2005. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=case1120143436
Virginia Tech
3.
Liu, Wenduo.
Alternative structures for integrated electromagnetic passives.
Degree: PhD, Electrical and Computer Engineering, 2006, Virginia Tech
URL: http://hdl.handle.net/10919/27419
► The demand for high power density keeps driving the development of electromagnetic integration technologies in the field of power electronics. Based on planar homogeneous integrated…
(more)
▼ The demand for high power density keeps driving the development of electromagnetic integration technologies in the field of power electronics. Based on planar homogeneous integrated structures, the mechanism of the electromagnetic integration of passives has been investigated with distributed-parameter models. High order modeling of integrated passives has been developed to investigate the electromagnetic performance. The design algorithm combining electromagnetic design and loss models has been developed to optimize and evaluate the spiral winding
structure. High power density of 480 W/in3 has been obtained on the prototype.
Due to the structural limitation, the currently applied planar spiral winding
structure does not sufficiently utilize the space, and the
structure is mechanically vulnerable. The improvement on structures is necessary for further application of integrated passives. The goal of this research is to investigate and evaluate alternative structures for high-power-density integrated passives. The research covers electromagnetic modeling, constructional study, design algorithm, loss modeling, thermal management and implementation technology
The symmetric single layer
structure and the
stacked structure are proposed to overcome the disadvantages of the currently applied planar spiral winding
structure. Because of the potential of high power density and low power loss, the
stacked structure is selected for further research. The structural characteristics and the processing technologies are addressed.
By taking an integrated LLCT module as the study case, the general design algorithm is developed to find out a set of feasible designs. The obtained design maps are used to evaluate the constraints from spatial, materials and processing technologies for the
stacked structure.
Based on the assumption of one-dimensional magnetic filed on the cross-section and linear current distribution along the longitudinal direction of the
stacked structure, the electromagnetic field distribution is analyzed and the loss modeling is made. The experimental method is proposed to measure the loss and to verify the calculation.
The power loss in the module leads to thermal issues, which limit the processed power of power electronics modules and thus limit the power density. To further improve the power handling ability of the module, the thermal management is made based on loss estimation. The heat extraction technology is developed to improve the heat removal ability and further improve the power density of integrated passives.
The experimental results verify the power density improvement from the proposed
stacked structure and the applied heat extraction technology. The power density of 1147 W/in3 (70 W/cm3) is achieved in the implemented LLCT module with the efficiency of 97.8% at output power of 1008W.
Advisors/Committee Members: van Wyk, Jacobus Daniel (committeechair), Odendaal, Willem Gerhardus (committee member), Wang, Fei Fred (committee member), Lu, Guo-Quan (committee member), Liu, Yilu (committee member).
Subjects/Keywords: Alternative structure; integrated passives; electromagnetic integration; asymmetric performance; high power density; design approach; implementation technology; heat extraction technology; loss measurement; stacked structure; interconnection; electromagnetic modeling
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APA ·
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APA (6th Edition):
Liu, W. (2006). Alternative structures for integrated electromagnetic passives. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/27419
Chicago Manual of Style (16th Edition):
Liu, Wenduo. “Alternative structures for integrated electromagnetic passives.” 2006. Doctoral Dissertation, Virginia Tech. Accessed April 17, 2021.
http://hdl.handle.net/10919/27419.
MLA Handbook (7th Edition):
Liu, Wenduo. “Alternative structures for integrated electromagnetic passives.” 2006. Web. 17 Apr 2021.
Vancouver:
Liu W. Alternative structures for integrated electromagnetic passives. [Internet] [Doctoral dissertation]. Virginia Tech; 2006. [cited 2021 Apr 17].
Available from: http://hdl.handle.net/10919/27419.
Council of Science Editors:
Liu W. Alternative structures for integrated electromagnetic passives. [Doctoral Dissertation]. Virginia Tech; 2006. Available from: http://hdl.handle.net/10919/27419
4.
Hawatmeh, Derar Fayez.
Three Dimensional Direct Print Additively Manufactured High-Q Microwave Filters and Embedded Antennas.
Degree: 2018, University of South Florida
URL: https://scholarcommons.usf.edu/etd/7165
► The need for miniaturized, and high performance microwave devices has focused significant attention onto new fabrication technologies that can simultaneously achieve high performance and low…
(more)
▼ The need for miniaturized, and high performance microwave devices has focused significant attention onto new fabrication technologies that can simultaneously achieve high performance and low manufacturing complexity. Additive manufacturing (AM) has proven its capability in fabricating high performance, compact and light weight microwave circuits and antennas, as well as the ability to achieve designs that are complicated to fabricate using other manufacturing approaches. Direct print additive manufacturing (DPAM) is an emerging AM process that combines the fused deposition modeling (FDM) of thermoplastics with micro-dispensing of conductive and insulating pastes. DPAM has the potential to jointly combine high performance and low manufacturing complexity, along with the possibility of real-time tuning.
This dissertation aims to leverage the powerful capabilities of DPAM to come-up with new designs and solutions that meet the requirements of rapidly evolving wireless systems and applications. Furthermore, the work in this dissertation provides new techniques and approaches to alleviate the drawbacks and limitations of DPAM fabrication technology. Firstly, the development of 3D packaged antenna, and antenna array are presented along with an analysis of the inherent roughness of 3D printed structures to provide a deeper understanding of the antenna RF performance. The single element presents a new volumetric approach to realizing a 3D half-wave dipole in a packaged format, where it provides the ability to keep a signal distribution network in close proximity to the ground plane, facilitating the implementation of ground connections (e.g. for an active device), mitigating potential surface wave losses, as well as achieving a modest (10.6%) length reduction. In addition, a new approach of implementing conformal antennas using DPAM is presented by printing thin and flexible substrate that can be adhered to 3D structures to facilitate the fabrication and reduce the surface roughness. The array design leverages direct digital manufacturing (DDM) technology to realize a shaped substrate structure that is used to control the array beamwidth. The non-planar substrate allows the element spacing to be changed without affecting the length of the feed network or the distance to the underlying ground plane.
The second part describes the first high-Q capacitively-loaded cavity resonator and filter that is compatible with direct print additive manufacturing. The presented design is a compromise between quality factor, cost and manufacturing complexity and to the best of our knowledge is the highest Q-factor resonator demonstrated to date using DPAM compatible materials and processes. The final version of the single resonator achieves a measured unloaded quality factor of 200-325 over the frequency range from 2.0 to 6.5 GHz. The two pole filter is designed using a coupled-resonator approach to operate at 2.44 GHz with 1.9% fractional bandwidth. The presented design approach simplifies evanescent-mode filter fabrication, eliminating…
Subjects/Keywords: 3D-printing; Dipole; Picosecond laser machining; Quality factor; Array; Non-planar; Capacitively-loaded cavity; Evanescent-mode; Stacked structure; Vertically Coupled; Electrical and Computer Engineering; Electromagnetics and Photonics
…29
Figure 3.18 Array structure (a) Total structure (b) Feeding network… …37
Figure 4.2
Evanescent-mode resonator structure… …59
Figure 4.26 Vertically-stacked capacitively-loaded cavity filter
(all dimensions… …61
Figure 4.28 Fabrication and assembly steps of the vertically-stacked filter… …62
Figure 4.29 Fabricated vertically-stacked filter…
Record Details
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APA ·
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MLA ·
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CSE |
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Manager
APA (6th Edition):
Hawatmeh, D. F. (2018). Three Dimensional Direct Print Additively Manufactured High-Q Microwave Filters and Embedded Antennas. (Thesis). University of South Florida. Retrieved from https://scholarcommons.usf.edu/etd/7165
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Hawatmeh, Derar Fayez. “Three Dimensional Direct Print Additively Manufactured High-Q Microwave Filters and Embedded Antennas.” 2018. Thesis, University of South Florida. Accessed April 17, 2021.
https://scholarcommons.usf.edu/etd/7165.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Hawatmeh, Derar Fayez. “Three Dimensional Direct Print Additively Manufactured High-Q Microwave Filters and Embedded Antennas.” 2018. Web. 17 Apr 2021.
Vancouver:
Hawatmeh DF. Three Dimensional Direct Print Additively Manufactured High-Q Microwave Filters and Embedded Antennas. [Internet] [Thesis]. University of South Florida; 2018. [cited 2021 Apr 17].
Available from: https://scholarcommons.usf.edu/etd/7165.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Hawatmeh DF. Three Dimensional Direct Print Additively Manufactured High-Q Microwave Filters and Embedded Antennas. [Thesis]. University of South Florida; 2018. Available from: https://scholarcommons.usf.edu/etd/7165
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
. 
Open Access Theses and Dissertations
