Parametric Modeling of Biomimetic Cortical Bone Microstructure for Additive Manufacturing (open access)

Parametric Modeling of Biomimetic Cortical Bone Microstructure for Additive Manufacturing

This articles presents a novel algorithm for generating in-silico biomimetic models of a cortical bone microstructure towards manufacturing biomimetic bone via additive manufacturing. The software provides a tool for physicians or biomedical engineers to develop models of cortical bone that include the inherent complexity of the microstructure.
Date: February 21, 2019
Creator: Robles Linares-Alvelais, José; Ramírez-Cedillo, Erick; Siller Carrillo, Héctor Rafael; Rodríguez, Ciro A. & Martínez-López, J. Israel
Object Type: Article
System: The UNT Digital Library

Construction Management Methods and Techniques in Army Tactical Shelter

Access: Use of this item is restricted to the UNT Community
This thesis presents a research effort aimed at developing using construction methods and techniques in army tactical shelter. The beginning step focuses on developing and identifying different activities and work breakdown structure applicable in shelter prototype. The next step focuses on identifying resource allocation. This include allocate resources based on the delivered project as per alternative one and for the second alternative as optimization, resource allocation modified and tried to level and minimize resource peak. In addition, the cost calculated for the whole project as well as for each WBS and activities which consider as alternative one and in the second alternative, cost mitigation applied according to available resources and adjusting predecessors and successors of each activity. In conclusion, two alternatives compared, available outcome presents, and future work suggested for the project team to continue this effort.
Date: December 2019
Creator: Yeganehtalab, Babak
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Fabrication and Testing of Biomimetic Microstructures for Walkway Tribometers (open access)

Fabrication and Testing of Biomimetic Microstructures for Walkway Tribometers

The main objective of this work is to give contribution in both additive manufacturing (AM) and tribometry derived from the application and study of materials available with the use of biomimetic designs. Additional contributions are determining what effects treatments for flooring surfaces may have on the dynamic coefficient of friction and the effects of these products on common surfaces. The validity of the proposed methodology for a proof of concept was demonstrated by comparing measured dynamic coefficient of friction for designs using standardized equipment and comparing these values to plantar skin tested using an accepted and standardized testing method that has been extensively researched and validated. Initial biomimetic designs and characteristics unique to each design were researched and compared. Eleven designs were selected to be fabricated, tested, and compared to select the most desirable applications for further investigation. Research into potential treatments commercially available for use was done to determine the efficacy of these products. Prototype sensor designs were selected and fabricated using direct light processing (DLP) technology. Examination of the measured values was done through an analysis of the variances in the response variable and comparisons using Fisher and Tukey pairwise comparison method. Future work recommendations are provided for …
Date: December 2019
Creator: Haney, Christopher Willard
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Design Method of Cold-Formed Steel Framed Shear Wall Sheathed by Structural Concrete Panel

Access: Use of this item is restricted to the UNT Community
The objective of this research is developing a new method of design for cold-formed steel framed shear wall sheathed by ¾" thick USG structural panel concrete subfloor using a predictive analytical model and comparing the results obtained from the model with those achieved from real testing to verify the analytical model and predicted lateral load-carrying capacity resulted from that. Moreover, investigating the impact of various screw spacings on shear wall design parameter such as ultimate strength, yield strength, elastic stiffness, ductility ratio and amount of energy dissipation is another purpose of this research.
Date: December 2019
Creator: Ashkanalam, Aida
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Cold-Formed Steel Member Connections Using BAC Screw Fasteners

Access: Use of this item is restricted to the UNT Community
In this project, the main research objective is intend to seek criteria for evaluating the capacity of BAC screw fasteners with mixed configuration of waterproof seal washer, sealer tape and different pre-drill holes to determine shear and tension strength values for the screws used in cold-formed steel connections. The thesis presents the design methods and test program conducted to investigate the behavior and strength of the screw connections in shear and tension test. Test results were compared with AISI design provisions to determine if new design equations will be developed for those screws used in BAC cooling tower applications. LRFD resistance factors and ASD safety factors were investigated to the proposed design equations.
Date: May 2019
Creator: Li, Xun
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Topology and Lattice-Based Structural Design Optimization for Additively Manufactured Medical Implants (open access)

Topology and Lattice-Based Structural Design Optimization for Additively Manufactured Medical Implants

Topology-based optimization techniques and lattice structures are powerful ways to accomplish lightweight components with enhanced mechanical performance. Recent developments in additive manufacturing (AM) have led the way to extraordinary opportunities in realizing complex designs that are derived from topology and lattice-based structural optimization. The main aim of this work is to give a contribution, in the integration between structural optimization techniques and AM, by proposing a setup of a proper methodology for rapid development of optimized medical implants addressing oseeointegration and minimization of stress shielding related problems. The validity of the proposed methodology for a proof of concept was demonstrated in two real-world case studies: a tibia intramedullary implant and a shoulder hemi prosthetics for two bone cancer patients. The optimization was achieved using topology optimization and replacement of solid volumes by lattice structures. Samples of three lattice unit cell configurations were designed, fabricated, mechanically tested, and compared to select the most proper configuration for the shoulder hemi prosthesis. Weight reductions of 30% and 15% were achieved from the optimization of the initial design of the tibia intramedullary implant and the shoulder hemiprosthesis respectively compared to initial designs. Prototypes were fabricated using selective laser melting (SLM) and direct light processing …
Date: May 2019
Creator: Peto, Marinela
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Microfluidic-Based Fabrication of Photonic Microlasers for Biomedical Applications (open access)

Microfluidic-Based Fabrication of Photonic Microlasers for Biomedical Applications

Optical microlasers have been used in different engineering fields and for sensing various applications. They have been used in biomedical fields in applications such as for detecting protein biomarkers for cancer and for measuring biomechanical properties. The goal of this work is to propose a microfluidic-based fabrication method for fabricating optical polymer based microlasers, which has advantages, over current methods, such us the fabrication time, the contained cost, and the reproducibility of the microlaser's size. The microfluidic setup consisted of microfluidic pumps and a flow focusing droplet generator chip made of polydimethylsiloxane (PDMS). Parameters such as the flow rate (Q) and the pressure (P) of both continuous and dispersed phases are taken into account for determining the microlaser's size and a MATLAB imaging tool is used to reduce the microlaser's diameter estimation. In addition, two applications are discussed: i) electric field measurements via resonator doped with Di-Anepps-4 voltage sensitive dye, and ii) strain measurements in a 3D printed bone-like structure to mimic biomedical implantable sensors.
Date: December 2019
Creator: Cavazos, Omar
Object Type: Thesis or Dissertation
System: The UNT Digital Library