Engineering Commons^™

Degradation Of High Performance Polymeric Fibers: Effects Of Sonication, Humidity And Temperature On Poly (P-Phenylene Terephthalamide) Fibers, Nelyan Lopez-Perez

Open Access Theses

High performance fibers are characterized by properties such as high strength and resistance to chemicals and heat. Due to their outstanding properties, they are used on applications under harsh environments that can degrade and decrease their performance. Fiber degradation due to different chemical and mechanical factors, is a process that begins at a microstructural level. Changes in the polymer’s chemical or physical structure can alter their mechanical properties. Knowledge of the structure-properties relationship and the effects of environmental chemical and physical factors over time, is crucial for the improvement and development of high performance fibers.

In this study ballistic fibers …

Formation Of Trihalomethanes (Thms) As Disinfection By-Products (Dbps) When Treated Municipal Wastewater Is Disinfected With Sodium Hypochlorite, Helene Kassouf

USF Tampa Graduate Theses and Dissertations

Disinfection is an essential process in the treatment of municipal wastewater before the treated wastewater can be discharged to the environment. Hillsborough County's Northwest Regional Water Reclamation Facility (NWRWRF) in Tampa, Florida, currently uses ultraviolet (UV) light for disinfection. However, this method has proven expensive to implement and maintain, and may not be effective if the light transmission is poor. For these reasons, Hillsborough County is considering switching from UV light to sodium hypochlorite for disinfection. However, hypochlorite (chlorine) disinfection has disadvantages as well, such as the production of disinfection by-products (DBPs) such as trihalomethanes (THM) and haloacetic acids (HAAs), …

Heat Of Fusion Of Primary Alcohol Confined In Nanopores, Harrisonn Griffin

Honors Theses

Melting behavior of physically confined 1-decanol in nano porous silica was probed using a Differential Scanning Calorimeter (DSC). In agreement with the Gibbs-Thomson prediction, we observe that the melting temperature of the confined 1-decanol scales inversely with the physical size of the pores. Contrary to the assumption used in developing the Gibbs-Thomson equation, however, the apparent heat of fusion decreases as the pore size decreases. Previously, several models have been proposed where interfacial layers of molecules do not participate in the phase transition and thereby would not contribute to the heat of fusion. While these could reconcile the seeming contradiction, …

The Effects Of Latency On 3d Interactive Data Visualizations, Allen Korenevsky

Master's Theses

Interactive data visualizations must respond fluidly to user input to be effective, or so we assume. In fact it is unknown exactly how fast a visualization must run to present every facet within a dataset. An engineering team with limited resources is left with intuition and estimates to determine if their application performs sufficiently well.

This thesis studies how latency affects users' comprehension of data visualizations, specifically 3D geospatial visualizations with large data sets. Subjects used a climate visualization showing temperatures spanning from the 19th to the 21st century to answer multiple choice questions. Metrics like their eye movements, time …

Bbq Grill Temperature Uniformity Study, Monty Dodge Jr, Samuel Melo

Mechanical Engineering

Bull Outdoor Products, Incorporated, a barbeque grill and outdoor kitchen manufacturer, sponsored this project with the intent of improving the temperature uniformity across the surface of their barbecue grills. For this project, the Cal Poly team of mechanical engineering students, Monty Dodge Jr. and Samuel Melo, used the Brahma grill head model with setups for both natural gas and propane. In order to determine exactly what the uniformity across the grill surface was, the student team designed a testing apparatus which would measure a grid of temperature locations one inch apart spanning an area 16 by 36 inches. Developing a …

Deflector Effects In Fixed Bed (Biomass) Combustors And Non-Combusting Packed Beds, Babak Rashidian

Theses: Doctorates and Masters

Combustion can be used to thermally process biomass fuels and yield both heat and power in a sustainable manner. At present, direct combustion of solid biomass is the primary approach for generating electricity and heat when these fuels are used at a commercial scale.

Deflectors have been used in the freeboard section of industrial combustors to reduce radiant heat loss through flue gases and for particle emissions abatement. Freeboard deflectors can also influence emissions and freeboard temperature distributions by changing the flow dynamics. Despite much research into laboratory scale biomass combustion and packed beds, there have been no systematic studies …

Oxidation Resistance Of Nanocrystalline 316l Stainless Steel Processed By High Pressure Torsion, Kevin J. Meisner

Williams Honors College, Honors Research Projects

High Pressure Torsion (HPT) is a materials processing method used to refine the grain size of metallic materials through the application of simultaneous axial and torsional strain. HPT is reported to result in nanocrystalline structure, which the current scientific literature suggests may improve the high temperature oxidation resistance by enhancing diffusion of solutes, particularly Cr, to the surface to form a protective external oxide scale. If oxidation resistance is improved, this possibly allows the use of 316L in oxidizing environments where more expensive alloys are typically used. However, the influence of grain refinement to nanoscale on various properties have been …

The Effects Of Micro-Dimple Texture On The Friction And Thermal Behavior Of A Point Contact, Utsav Kamleshbhai Parmar

Browse all Theses and Dissertations

This study investigates the effects of the micro-dimple texture on the friction and surface temperature performances of a ball-on-disk contact, operating under the speed and load ranges that cover typical gearing applications. Circular shaped micro-dimple arrays with different dimple center distances and dimple depths are implemented on the ball surface to quantify the impacts of these two parameters on the friction coefficient and the maximum ball surface temperature. In addition, the contacts of three surface texture combinations, namely micro-dimpled and polished ball surface versus polished disk surface, polished ball surface versus polished disk surface and ground ball surface versus ground …