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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.
151

Impact of Osmolytes and Cation on Actin Filament Assembly and Mechanics

Kalae, Abdulrazak 01 January 2023 (has links) (PDF)
Actin is a highly abundant protein in most eukaryotic cells. The assembly of actin monomers to double helical filaments is crucial for many cellular functions, including cell movement and cell division. Actin filament assembly in cells occurs in a crowded intracellular environment consisting of various molecules, including cations and organic osmolytes. Recent studies show that cation binding stiffens actin filaments, and a small organic osmolyte trimethylamine-N-oxide (TMAO) modulates filament assembly. However, how cations and TMAO combined affect actin filament mechanics is not understood. We hypothesize that depending on the concentrations of cations and osmolytes, there will be different effects on the stiffness and assembly of actin filaments. In this study, using TIRF we evaluate actin filament mechanics and assembly. Our findings indicate that when TMAO is present alone, it can increase the elongation rate and stiffness of actin filaments, however the inclusion of potassium levels alongside TMAO reduces the persistence length of actin filaments, suggesting a decrease in filament stiffness compared to the influence of TMAO alone. Furthermore, the elongation rate of actin filaments decreases when both TMAO and potassium ions are present. This study will help us better understand how cations and osmolytes together can affect actin filament mechanics in the living cells.
152

Mechanical Characterization of Anisotropic Fused Deposition Modeled Polylactic Acid Under Combined Monotonic Bending and Torsion Conditions

Santomauro, Aaron T 01 January 2019 (has links)
Mechanical strength of polylactic acid (PLA) is increasingly relevant with time because of its attractive mechanical properties and 3D printability. Additive manufacturing (AM) methods, such as fused deposition modeling (FDM), stereolithography (SLA), and selective laser sintering (SLS), serve a vital role in assisting designers with cheap and efficient generation of the desired components. This document presents research to investigate the anisotropic response of multi-oriented PLA subjected to multiple monotonic loading conditions. Although empirical data has previously been captured for multi-oriented PLA under tensile and compressive loading conditions, the data has yet to be applied with regard to a representative component geometry. The tensile and compressive empirical data were ultimately used to develop elastic and yield constitutive models which aided in the characterization of PLA under torsion and bending. This representative component geometry is expected to experience a combined torsion and bending load condition in an effort to address this integral gap in the mechanical properties of multi-oriented PLA. In addition to the acquired empirical data, finite element analysis (FEA) and analytical modeling are employed to supplement the accurate modeling of future component analysis. As a result of the proposed array of experiments, the torsional and bending capabilities of PLA are forecasted to vary based on the print orientation. Lastly, the broader impact of this work is dedicated to addressing the material's capability to operate in environments which possess significant torsion and bending such as model aircraft wings and shafts for remote controlled cars.
153

Preliminary characterization of physical and mechanical properties of species used in staircase manufactures

Grecca Turkot, Cristian 09 August 2019 (has links)
In Phase I of this study, the purpose was to compare mechanical and physical wood properties from current wood supplies to those from previous studies (Newlin and Wilson 1917, Markwardt and Wilson 1935, wood handbook 2010). The results indicate that minor changes have occurred in the hardwood species values from the previous two studies with a few exceptions. Differences, where they occurred, could be explained by the growth locations of each sample. Differences between pine values occurred for MOE and MOR, an increase in MOE and a decrease in MOR. The objective of Phase II was to correlate the non-destructive and destructive testing methods. The non-destructive test by longitudinal vibration wave can be used to predict the static modulus of elasticity since it is strongly correlated with the destructive static bending test for all the three methods used (A-Grader, FFT and Smart-Thumper).
154

Finite Element Method For The Cold Forming Of Copper Tubing

Batol, David Tello 04 August 2001 (has links)
The objective of this research is to simulate a pushorming operation for the manufacturing of copper tube elbows using the finite element method. This model may be useful in the design of tooling. The influences of lubricant type, the tube blank material, and a minute surface defect are considered in the model. Tensile tests of annealed copper specimens are conducted to derive stress-strain data, defining the material behavior of the copper tube blank. In addition, friction tests are performed to obtain static and dynamic friction coefficients for a wet and dry lubricant types, which are used in the forming process. The finite element study of the forming operation has proven to require a considerable amount of time for modeling and processing. The verification examples and the pushorming models demonstrate the ability of the finite element program to include: contact with friction, the actuating of hydraulically controlled components, buckling, and nonlinearity.
155

<i>In Vivo</i> Strains in the Femur of the Nine-Banded Armadillo (<i>Dasypus novemcinctus</i>)

Copploe, Joseph V., II 24 June 2014 (has links)
No description available.
156

Flanging and Bending of Advanced High Strength Steels

Srinivasan, Ganapathy January 2014 (has links)
No description available.
157

Investigation of fracture and springback in hot and cold forming

Kishore, Siddharth January 2014 (has links)
No description available.
158

Influence of Surface Finish on Bending Fatigue of Forged Steel Including Heating Method, Hardness, and Shot Cleaning Effects

McKelvey, Sean Ambrose 22 May 2011 (has links)
No description available.
159

Modern Craft: Linking Material, Process and Environment

Hilligoss, Peter Z. 28 July 2009 (has links)
No description available.
160

The boundary element method and its application to the analysis of bolted connections

Ichikawa, Kazuhiko January 1984 (has links)
No description available.

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