subject:(Young s modulus)

1. Eckert, Matthias Bastian. Avaliação da influência da retração inicial no controlo da fissuração dos betões.

Degree: 2013, Universidade de Évora

URL: http://www.rcaap.pt/detail.jsp?id=oai:dspace.uevora.pt:10174/10911

► A fissuração em idade precoce reemergiu como um problema em betão/argamassa moderno, com o uso de materiais com altas resistências mecânicas. Este tipo de fissuração… (more)

▼ A fissuração em idade precoce reemergiu como um problema em betão/argamassa moderno, com o uso de materiais com altas resistências mecânicas. Este tipo de fissuração resulta da retração do betão, que quando associada a restrições internas e externas cria tensões, aumentando a suscetibilidade à fissuração. Distinguem-se vários tipos de retração: plástica, química, autogénea térmica e por secagem, que são influenciadas por fatores ambientais e fatores intrínsecos ao material. A fissuração permite o ingresso de agentes atmosféricos que conduzem a uma deterioração pré-matura do betão, cuja mitigação constitui a motivação desta tese de mestrado. O objetivo do trabalho experimental consiste em avaliar a influência dos tempos de presa na atuação de adições expansivas em betão autocompactável. Espera-se que diferentes estados de rigidez microestrutural modifiquem o efeito de expansão. Para esse fim foram executados ensaios de: trabalhabilidade, tempos de presa, resistência à compressão e tração, módulo de elasticidade, retração química e total, perda de peso e por último, o ensaio de anel. Os resultados do trabalho experimental mostram que o aumento dos tempos de presa prolongam a fase expansiva, o que levou à diminuição de retração e fissuração a médio prazo, mas a longo prazo não se verificou qualquer alteração da retração. Conclui-se que este estudo constitui uma informação importante para avaliar o efeito de retardadores de presa nas propriedades avaliadas e que a sua combinação com expansivos trás algumas melhorias na fissuração;## ABSTRACT: Evaluation of the Influence of Early Age Shrinkage on the Control of Concrete Cracking The early age cracking reemerged as a problem in modern concrete/mortar, with the use of high strength materials. This type of cracking results from the concrete shrinkage, when it is associated to selfand external-restraint it creates tensions, increasing the cracking susceptibility. There are discriminated several types of shrinkage: plastic, chemical, autogenous, thermal and drying, which are influenced by environmental factors and inherent factors to the material. The cracking allows the ingress of atmospheric agents that lead to pre-mature deterioration of concrete, whose mitigation is the motivation of this master thesis. The objective of the experimental work consists in evaluate the influence of setting-time on the performance of expansive admixtures in self-compacting concrete. It is expected that different states of microstructural stiffness modifies the expansion effect. For this purpose were executed tests for: workability; setting time; compressive and tensile-strength; Young's modulus; chemical and overall shrinkage; mass loss and finally the Ring Test. The results of the experimental work show that the increase of setting time extends the expansive phase, that leaves to an decrease of shrinkage and cracking at medium term, but at long term there was no change of the shrinkage. It can be concluded that this study constitutes an important information to evaluate the effect of… Advisors/Committee Members: Oliveira, Miguel José Pereira das D. S. de, Ribeiro, António Carlos Bettencourt Simões.

Subjects/Keywords: Fissuração; Módulo de elasticidade; Adições expansivas; Tempos de presa; Shrinkage; Cracking; Young´s modulus; Expansive admixtures; Setting time

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Eckert, M. B. (2013). Avaliação da influência da retração inicial no controlo da fissuração dos betões. (Thesis). Universidade de Évora. Retrieved from http://www.rcaap.pt/detail.jsp?id=oai:dspace.uevora.pt:10174/10911

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Eckert, Matthias Bastian. “Avaliação da influência da retração inicial no controlo da fissuração dos betões.” 2013. Thesis, Universidade de Évora. Accessed January 23, 2020. http://www.rcaap.pt/detail.jsp?id=oai:dspace.uevora.pt:10174/10911.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Eckert, Matthias Bastian. “Avaliação da influência da retração inicial no controlo da fissuração dos betões.” 2013. Web. 23 Jan 2020.

Vancouver:

Eckert MB. Avaliação da influência da retração inicial no controlo da fissuração dos betões. [Internet] [Thesis]. Universidade de Évora; 2013. [cited 2020 Jan 23]. Available from: http://www.rcaap.pt/detail.jsp?id=oai:dspace.uevora.pt:10174/10911.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Eckert MB. Avaliação da influência da retração inicial no controlo da fissuração dos betões. [Thesis]. Universidade de Évora; 2013. Available from: http://www.rcaap.pt/detail.jsp?id=oai:dspace.uevora.pt:10174/10911

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

The Ohio State University

2. Sivakumar, Lalitha. Effect of DDR2 on Rheology of Collagen type I Fibers.

Degree: MS, Biomedical Engineering, 2009, The Ohio State University

URL: http://rave.ohiolink.edu/etdc/view?acc_num=osu1243537065

► Collagen fibers in the vertebrate tissue are responsible for its tensile strength. A disruption in the morphological or rheological properties of collagen fibers is bound… (more)

▼ Collagen fibers in the vertebrate tissue are responsible for its tensile strength. A disruption in the morphological or rheological properties of collagen fibers is bound to impact tensile strength and contractility of tissues and affect physiological processes. Several collagen binding proteins have been shown to affect the morphology of collagen fibers. However little is understood about how these morphological changes affect the rheology of collagen fibers. It was recently established that binding of the discoidin domain receptor (DDR2) with collagen type I resulted in disruption of the native structure and morphology of collagen fibers. These results led us to investigate if DDR2 affects the rheological properties of collagen fibers. We used an analytical approach to determine the persistence length (PL) of collagen fibers using transmission electron microscope (TEM) images of immobilized collagen. The fluctuations in the curvature of collagen fibers formed in-vitro (with and without DDR2 or a control protein TrkB) were analyzed to ascertain their PL. For collagen fibers (15 µg/ml), we found a PL of 9.10 µm (± 0.33 µm) whereas collagen fibers formed in the presence of DDR2-Fc under similar conditions had a 40% reduction in PL to 5.20 µm (± 0.20 µm). These results show that DDR2 significantly reduced the PL of collagen fibers. We also found that PL for native collagen fibers increases monotonically as a function of collagen concentration with little dependence on fiber diameter. These results reveal that differences in PL are mainly due to the amount and/or density of collagen incorporated into the fibers. The PL values and fiber-diameter measurements were utilized to ascertain the Young’s Modulus (E) of collagen fibers formed in the presence and absence of DDR2. E for collagen fibers with and without DDR2 was 300 Pa (± 12 Pa) and 1300 Pa (± 47 Pa) respectively. Further collagen gel-contraction studies were carried out to evaluate how cells expressing the soluble or membrane anchored isoforms of DDR2 (and lacking the intracellular kinase domain of DDR2) affect contraction of collagen gels. Cells overexpressing DDR2 ECD and DDR2 /-KD inhibit contraction of collagen gels by ~30% and ~15% respectively in comparison to the untransfected cells. We elucidate that DDR2 reduces the PL and E of collagen fibers and decreases contractility of collagen fibers by osteoblast cells. Our results signify a physiological role of DDR2 in modulating matrix stiffness, which may be especially relevant in developing tissues and matrix remodeling. Advisors/Committee Members: AGARWAL, GUNJAN (Advisor).

Subjects/Keywords: Biomedical Research; collagen; fiber; discoidin domain receptor 2 (DDR2); persistence length; transmission electron microscopy; Young&8217; s modulus

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Sivakumar, L. (2009). Effect of DDR2 on Rheology of Collagen type I Fibers. (Masters Thesis). The Ohio State University. Retrieved from http://rave.ohiolink.edu/etdc/view?acc_num=osu1243537065

Chicago Manual of Style (16^th Edition):

Sivakumar, Lalitha. “Effect of DDR2 on Rheology of Collagen type I Fibers.” 2009. Masters Thesis, The Ohio State University. Accessed January 23, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1243537065.

MLA Handbook (7^th Edition):

Sivakumar, Lalitha. “Effect of DDR2 on Rheology of Collagen type I Fibers.” 2009. Web. 23 Jan 2020.

Vancouver:

Sivakumar L. Effect of DDR2 on Rheology of Collagen type I Fibers. [Internet] [Masters thesis]. The Ohio State University; 2009. [cited 2020 Jan 23]. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=osu1243537065.

Council of Science Editors:

Sivakumar L. Effect of DDR2 on Rheology of Collagen type I Fibers. [Masters Thesis]. The Ohio State University; 2009. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=osu1243537065

Case Western Reserve University

3. Harris, James Patrick. The Glia-Neuronal Response to Cortical Electrodes: Interactions with Substrate Stiffness and Electrophysiology.

Degree: PhD, Biomedical Engineering, 2011, Case Western Reserve University

URL: http://rave.ohiolink.edu/etdc/view?acc_num=case1320950439

► The overall goal of this work is to improve intracortical electrodes for chronic recordings from the brain. The studies in the dissertation examine material stiffness,… (more)

▼ The overall goal of this work is to improve intracortical electrodes for chronic recordings from the brain. The studies in the dissertation examine material stiffness, the tissue response, and electrode recording quality to enable improvements. Intracortical electrodes can improve the quality of life of patients with severe paralysis via brain machine interfaces (BMIs), but factors limit electrode widespread clinical usage. One factor of implanted intracortical electrodes is that the number of recorded signals decreases over time, limiting the longevity of electrodes. The decrease is hypothesized to be from the tissue response to the electrodes. In this dissertation, we investigate the tissue response and its effect on electrode recordings. Specifically, we examine the role of material stiffness on the tissue response. Recently developed, a mechanically adaptive nanocomposite decreases its stiffness from 5 GPa to 12 MPa in vitro. Confirming in vitro work, we show that the nanocomposite is stiff enough for insertion, but softer than traditional BMI electrodes after brain implantation. The nanocomposite enables our examination of the role of material stiffness on tissue response. Implanting the soft nanocomposite and surface-matched stiff microwire, we examine the effect of stiffness on tissue response. At one month, greater neural density around the nanocomposite versus the microwire accompanies changes in mechanically associated factors, intermediate filaments and extracellular matrix components. At two months, the neural densities are similar between implant types, and neural density around the nanocomposite is maintained despite macrophage activation. The soft nanocomposite modifies the tissue response, and therefore, we examine whether the tissue response affects neural recordings. By using lipopolysaccharide (LPS) to promote the inflammatory response, LPS-treated animals show an increase in non-neural cells and a decrease in the neural cells near the implant. Additionally, the quality of recordings is reduced in LPS-treated animals. Though further research is necessary, the results of this work support the hypothesis that a softer material can improve long-term neural recording. The work guides electrode development to improve electrodes to offer patients with severe paralysis and other neurological deficits a better quality of life. Advisors/Committee Members: Tyler, Dustin (Committee Chair).

Subjects/Keywords: Biomedical Engineering; Brain; Neural Prosthesis; micromotion; cellulose; Cell encapsulation; electrode; Inflammation; Mechanical properties; Nanocomposite; Young&8217; s Modulus; Insertion Force

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Harris, J. P. (2011). The Glia-Neuronal Response to Cortical Electrodes: Interactions with Substrate Stiffness and Electrophysiology. (Doctoral Dissertation). Case Western Reserve University. Retrieved from http://rave.ohiolink.edu/etdc/view?acc_num=case1320950439

Chicago Manual of Style (16^th Edition):

Harris, James Patrick. “The Glia-Neuronal Response to Cortical Electrodes: Interactions with Substrate Stiffness and Electrophysiology.” 2011. Doctoral Dissertation, Case Western Reserve University. Accessed January 23, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=case1320950439.

MLA Handbook (7^th Edition):

Harris, James Patrick. “The Glia-Neuronal Response to Cortical Electrodes: Interactions with Substrate Stiffness and Electrophysiology.” 2011. Web. 23 Jan 2020.

Vancouver:

Harris JP. The Glia-Neuronal Response to Cortical Electrodes: Interactions with Substrate Stiffness and Electrophysiology. [Internet] [Doctoral dissertation]. Case Western Reserve University; 2011. [cited 2020 Jan 23]. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=case1320950439.

Council of Science Editors:

Harris JP. The Glia-Neuronal Response to Cortical Electrodes: Interactions with Substrate Stiffness and Electrophysiology. [Doctoral Dissertation]. Case Western Reserve University; 2011. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=case1320950439

4. Danoglidis, Panagiotis. Ανάπτυξη πολυλειτουργικών δομικών υλικών ενισχυμένων με νανοσωλήνες και νανοΐνες άνθρακα με επιλεκτικά αναβαθμισμένες μηχανικές και ηλεκτροχημικές ιδιότητες: βελτιστοποίηση της ακαμψίας θραύσης και της ικανότητας ανίχνευσης παραμορφώσεων και ρωγμών.

Degree: 2018, Democritus University of Thrace (DUTH); Δημοκρίτειο Πανεπιστήμιο Θράκης (ΔΠΘ)

URL: http://hdl.handle.net/10442/hedi/43630

► Cement based materials exhibit extremely brittle failure, low tensile strength, low strain capacity and are susceptible to cracking. These characteristics are serious shortcomings that not… (more)

▼ Cement based materials exhibit extremely brittle failure, low tensile strength, low strain capacity and are susceptible to cracking. These characteristics are serious shortcomings that not only impose constraints in structural design, but also affect the long term durability of structures and their performance in a life-cycle perspective. Current solutions for new concrete constructions, as recommended and enforced by design codes, has made significant progress in increasing the compressive strength of concrete leading to high strength and performance cement-based materials. However, these types of materials are characterized by increased brittleness and at the same time exhibiting low resistance to cracking.The present Doctoral Thesis entitled: “Functionally graded cement based nanocomposites with advanced mechanical properties and self-sensing ability” was highly motivated by the idea of developing high-performance and advanced self-sensing cementitious materials that could effectively be used as construction materials and at the same time exhibit self-sensing capability to monitor their strain and cracking. To increase the life of a structure, delaying the micro and macro cracking and increasing fracture resistance is very important. This can be achieved by using fibers at the nano scale: as all cracks are formed at the nano scale level, to suppress the initiation and growth of these cracks, the use of nanoscale fibers can enable notable structural concepts. The overall object of the Ph.D. thesis is to develop new high performance nanomodified cement based nanocomposites with substantially increased flexural strength, stiffness and toughness as well piezoresistive response. To achieve this, the cement based materials were reinforced at the nanoscale, by incorporating carbon nanotubes (CNTs) and carbon nanofibers (CNFs), as well as at the microscale by incorporating polypropylene (PP) microfibers.Carbon nanotubes and carbon nanofibers exhibit superior mechanical and electrical properties. Their supreme stiffness, high strength and aspect ratio make them excellent reinforcing candidate materials, offering outstanding improvements in the mechanical properties. Reinforcement at the nanoscale, in addition to providing fracture resistance, can also beneficially alter the nanostructure of cement based materials. Nanoscale carbon fibers are also highly conductive materials and when subjected to various deformations they have the ability to record electromechanical changes, expressing a linear and reversible piezoresistive response. As carbon nanoscale fibers adhere together due to van der Waals forces, agglomerates or bundles are formed that make their dispersion difficult and laborious. Konsta-Gdoutos et al. has focused on solving the major challenge associated with the incorporation of CNTs and CNFs in cementitious matrix in order to manufacture nanocomposites with good dispersion of CNTs/CNFs at a reasonably low volume fraction. At early research, cement pastes reinforced with small amount of CNTs and CNFs were…

Subjects/Keywords: Νανοσωλήνες άνθρακα; Νανοίνες άνθρακα; Ακαμψία θραύσης; Ικανότητα απορρόφησης ενέργειας; Μέτρο ελαστικότητας; Ειδική ηλεκτρική αντίσταση; Ηλεκτροχημική χωρητικότητα; Πιεζοαντιστατική απόκριση; Carbon nanotubes; Carbon nanofibers; Fracture toughness; Energy absorption capability; toughness indices; Young`s modulus; Resistivity; Capacitance; Piezoresistive response

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Danoglidis, P. (2018). Ανάπτυξη πολυλειτουργικών δομικών υλικών ενισχυμένων με νανοσωλήνες και νανοΐνες άνθρακα με επιλεκτικά αναβαθμισμένες μηχανικές και ηλεκτροχημικές ιδιότητες: βελτιστοποίηση της ακαμψίας θραύσης και της ικανότητας ανίχνευσης παραμορφώσεων και ρωγμών. (Thesis). Democritus University of Thrace (DUTH); Δημοκρίτειο Πανεπιστήμιο Θράκης (ΔΠΘ). Retrieved from http://hdl.handle.net/10442/hedi/43630

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Danoglidis, Panagiotis. “Ανάπτυξη πολυλειτουργικών δομικών υλικών ενισχυμένων με νανοσωλήνες και νανοΐνες άνθρακα με επιλεκτικά αναβαθμισμένες μηχανικές και ηλεκτροχημικές ιδιότητες: βελτιστοποίηση της ακαμψίας θραύσης και της ικανότητας ανίχνευσης παραμορφώσεων και ρωγμών.” 2018. Thesis, Democritus University of Thrace (DUTH); Δημοκρίτειο Πανεπιστήμιο Θράκης (ΔΠΘ). Accessed January 23, 2020. http://hdl.handle.net/10442/hedi/43630.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Danoglidis, Panagiotis. “Ανάπτυξη πολυλειτουργικών δομικών υλικών ενισχυμένων με νανοσωλήνες και νανοΐνες άνθρακα με επιλεκτικά αναβαθμισμένες μηχανικές και ηλεκτροχημικές ιδιότητες: βελτιστοποίηση της ακαμψίας θραύσης και της ικανότητας ανίχνευσης παραμορφώσεων και ρωγμών.” 2018. Web. 23 Jan 2020.

Vancouver:

Danoglidis P. Ανάπτυξη πολυλειτουργικών δομικών υλικών ενισχυμένων με νανοσωλήνες και νανοΐνες άνθρακα με επιλεκτικά αναβαθμισμένες μηχανικές και ηλεκτροχημικές ιδιότητες: βελτιστοποίηση της ακαμψίας θραύσης και της ικανότητας ανίχνευσης παραμορφώσεων και ρωγμών. [Internet] [Thesis]. Democritus University of Thrace (DUTH); Δημοκρίτειο Πανεπιστήμιο Θράκης (ΔΠΘ); 2018. [cited 2020 Jan 23]. Available from: http://hdl.handle.net/10442/hedi/43630.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Danoglidis P. Ανάπτυξη πολυλειτουργικών δομικών υλικών ενισχυμένων με νανοσωλήνες και νανοΐνες άνθρακα με επιλεκτικά αναβαθμισμένες μηχανικές και ηλεκτροχημικές ιδιότητες: βελτιστοποίηση της ακαμψίας θραύσης και της ικανότητας ανίχνευσης παραμορφώσεων και ρωγμών. [Thesis]. Democritus University of Thrace (DUTH); Δημοκρίτειο Πανεπιστήμιο Θράκης (ΔΠΘ); 2018. Available from: http://hdl.handle.net/10442/hedi/43630

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Delft University of Technology

5. He, H. Computational Modelling of Particle Packing in Concrete.

Degree: 2010, Delft University of Technology

URL: http://resolver.tudelft.nl/uuid:e54870ba-7db7-41cd-86f1-97c485500b34 ; urn:NBN:nl:ui:24-uuid:e54870ba-7db7-41cd-86f1-97c485500b34 ; urn:NBN:nl:ui:24-uuid:e54870ba-7db7-41cd-86f1-97c485500b34 ; http://resolver.tudelft.nl/uuid:e54870ba-7db7-41cd-86f1-97c485500b34

► Physical particle packing is becoming a hot topic in concrete technology as more and more types of granular materials are used in concrete either for… (more)

Subjects/Keywords: particle packing; image analysis; DEM; packing density; coordination number; FEM; the Youngs modulus; Fracture behaviour; self-healing

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

He, H. (2010). Computational Modelling of Particle Packing in Concrete. (Doctoral Dissertation). Delft University of Technology. Retrieved from http://resolver.tudelft.nl/uuid:e54870ba-7db7-41cd-86f1-97c485500b34 ; urn:NBN:nl:ui:24-uuid:e54870ba-7db7-41cd-86f1-97c485500b34 ; urn:NBN:nl:ui:24-uuid:e54870ba-7db7-41cd-86f1-97c485500b34 ; http://resolver.tudelft.nl/uuid:e54870ba-7db7-41cd-86f1-97c485500b34

Chicago Manual of Style (16^th Edition):

He, H. “Computational Modelling of Particle Packing in Concrete.” 2010. Doctoral Dissertation, Delft University of Technology. Accessed January 23, 2020. http://resolver.tudelft.nl/uuid:e54870ba-7db7-41cd-86f1-97c485500b34 ; urn:NBN:nl:ui:24-uuid:e54870ba-7db7-41cd-86f1-97c485500b34 ; urn:NBN:nl:ui:24-uuid:e54870ba-7db7-41cd-86f1-97c485500b34 ; http://resolver.tudelft.nl/uuid:e54870ba-7db7-41cd-86f1-97c485500b34.

MLA Handbook (7^th Edition):

He, H. “Computational Modelling of Particle Packing in Concrete.” 2010. Web. 23 Jan 2020.

Vancouver:

He H. Computational Modelling of Particle Packing in Concrete. [Internet] [Doctoral dissertation]. Delft University of Technology; 2010. [cited 2020 Jan 23]. Available from: http://resolver.tudelft.nl/uuid:e54870ba-7db7-41cd-86f1-97c485500b34 ; urn:NBN:nl:ui:24-uuid:e54870ba-7db7-41cd-86f1-97c485500b34 ; urn:NBN:nl:ui:24-uuid:e54870ba-7db7-41cd-86f1-97c485500b34 ; http://resolver.tudelft.nl/uuid:e54870ba-7db7-41cd-86f1-97c485500b34.

Council of Science Editors:

He H. Computational Modelling of Particle Packing in Concrete. [Doctoral Dissertation]. Delft University of Technology; 2010. Available from: http://resolver.tudelft.nl/uuid:e54870ba-7db7-41cd-86f1-97c485500b34 ; urn:NBN:nl:ui:24-uuid:e54870ba-7db7-41cd-86f1-97c485500b34 ; urn:NBN:nl:ui:24-uuid:e54870ba-7db7-41cd-86f1-97c485500b34 ; http://resolver.tudelft.nl/uuid:e54870ba-7db7-41cd-86f1-97c485500b34

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