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Nondestructive Evaluation Of 3d Printed, Extruded, And Natural Polymer Structures Using Terahertz Spectroscopy And Imaging, Alexander T. Clark

Dissertations

Terahertz (THz) spectroscopy and imaging are considered for the nondestructive evaluation (NDE) of various three-dimensional (3D) printed, extruded, and natural polymer structures. THz radiation is the prime candidate for many NDE challenges due to the added benefits of safety, increased contrast and depth resolution, and optical characteristic visualization when compared to other techniques. THz imaging, using a wide bandwidth pulse-based system, can evaluate the external and internal structure of most nonconductive and nonpolar materials without any permanent effects. NDE images can be created based on THz pulse attributes or a material’s spectroscopic characteristics such as refractive index, attenuation coefficient, or …

Hydrophobically Modified Isosorbide Dimethacrylates As Biomaterials For Bisphenol A Free Dental Fillings, Bilal Marie

Dissertations

Amalgam and Bisphenol A glycerolate dimethacrylate (BisGMA) are the main dental filling materials in use today. Because of the negative perception of amalgam and its lower esthetic appeal, as well as the desire to replace the endocrine disruptor Bisphenol A, which is the building block of BisGMA, there has been a critical need to search for safer alternatives to these dental filling materials.

Isosorbide is a sugar-based molecule generally recognized as safe. It has been extensively studied as a replacement to the Bisphenol A core in various materials. However, isosorbide is extremely hygroscopic, and water uptake in dental fillings causes …

Dental Professionals Occupational Noise Exposure And Its Auditory And Non-Auditory Effects, Alexis Frees

Theses

The purpose of this study was to assess noise exposure and its auditory and non-auditory effects on workers in five clinical departments in the School of Dental Medicine at Rutgers Biomedical Health Sciences Campus in Newark, New Jersey. The study included environmental noise level measurement, dental instrument sound level measurement, personal noise dosimetry and a questionnaire survey to assess non-auditory effects. Octave band analysis of environmental noise levels showed that they are slightly above the standard noise criteria for clinics, and measurements from six dental instruments confirm that they contribute higher sound pressure levels at the frequencies of 1000, 2000, …

Using Structural And Semantic Methodologies To Enhance Biomedical Terminologies, Zhe He

Dissertations

Biomedical terminologies and ontologies underlie various Health Information Systems (HISs), Electronic Health Record (EHR) Systems, Health Information Exchanges (HIEs) and health administrative systems. Moreover, the proliferation of interdisciplinary research efforts in the biomedical field is fueling the need to overcome terminological barriers when integrating knowledge from different fields into a unified research project. Therefore well-developed and well-maintained terminologies are in high demand. Most of the biomedical terminologies are large and complex, which makes it impossible for human experts to manually detect and correct all errors and inconsistencies. Automated and semi-automated Quality Assurance methodologies that focus on areas that are more …

Thermochemical Properties Of C3 To C5 Unsaturated Carbonyl Alkenes: Enthalpies Of Formation, Entropy, Heat Capacity, Bond Enthalpy, Ruiqi Jian

Theses

α,β and α-γ unsaturated carbonyl compounds are important classes of carbonyl compounds with the general structure R-(O=C)-Cα=Cβ-R’ and R-(O=Cγ)-Cβ-Cα=Cβ-R’. These compounds are utilized in industry and are also produced as intermediates of hydrocarbon oxidation in chemistry of the atmosphere and in combustion. These unsaturated carbonyls are common environmental pollutants, are frequently associated with adverse effects, and are considered to play an important role in human cancer. Their stability, thermochemical properties are important to understanding their reaction paths in atmospheric, combustion and bio related environments. Enthalpy, entropy, and heat capacity of unsaturated alkene molecules, and radicals corresponding to hydrogen atom …

Understanding The Origins Of Metastability In Thin Film Growth; Tantalum And The Early Group Vb-Vib Metals, Neme Okechukwu Nnolim

Dissertations

Tantalum (Ta) is a metal that is highly prized for its applications in a variety of industries, including the microelectronics industry, where it is largely used in thin film modifications in order to achieve various electronic, magnetic and structural capabilities in solid-state devices. Ta frequently forms metastable phases, including the well-known ß-phase, during the preparation of thin Ta films by standard film deposition methods such as sputtering and electro-deposition. In order to gain insight into Ta metastable phase formation, the Bain transformation mechanism is studied for Ta and the neighboring body centered cubic (bcc) transition metals in Groups 5 and …

Synthesis Of Bisphenol A Bis-2-Hydroxypropylmethacrylate (Bisgma) And Diethylchlorophosphate And 2-Hydroxyethylmethacrylate (Decp-Hema) And Preparation Of Dental Adhesives, Da Xie

Theses

BisGMA and DECP-HEMA were separately synthesized from Bisphenol A and glycidyl methacrylate and from diethylchlorophosphate and 2-hydroxyethyl-methacrylate. The structure of the monomer, BisGMA, was further analyzed by means of chromatography, VPO, IR, FTIR and GC-MASS.

Based on the main monomers, BisGMA, DECP-HEMA and an organosilane compound, a dental adhesive has been formulated. Although the tervile strength of the adhesive has been found to be not as good as the adhesive formulated by a previous worker (student), its applicability to teeth is more suitable for clinic practice.

Preparation And Testing Of Novel Dental Adhesives Based On Bis- Gma/Tegdma Monomer System, Deyun Sun

Theses

In this study, polymerizable phosphonate adhesives synthesized from Diethylchloro-phosphate and 2-Hydroxyethylmethylacrylate and formulated with G-methacryloxy-propyltrimethoxy silane is used in Bis-GMA/TEGDMA monomer system. All the raw materials and finished products are characterized with infrared spectra, vapor pressure osmometry, viscosity and gel test. The bonding strength to tooth materials is determined by Instron machine. The work emphasizes applying polymeric organic phosphonate adhesive to Bis-GMA/TEGDMA monomer system and investigates the appropriate conditions for the crosslinking of Bis-GMA/TEGDMA monomer system. Average bonding strength of 744 psi to enamel and 600 to dentine are ob¬tained in comparision to 550 psi to enamel for phosphonate/silane/MMA/PMMA and …