Engineering Commons^™

Dual-Axis Solar Tracker, Bryan Kennedy

All Undergraduate Projects

Renewable energies, and fuels that are not fossil fuel-based, are one of the prolific topics of debate in modern society. With climate change now becoming a primary focus for scientists and innovators of today, one of the areas for the largest amount of potential and growth is that of the capturing and utilization of Solar Energy. This method involves using a mechanical system to track the progression of the sun as it traverses the sky throughout the day. A dual-axis solar tracker such as the one designed and built for this project, can follow the sun both azimuthally and in …

Improving The Engineering Properties Of Pla For 3d Printing And Beyond, Carmen R. Rocha

Open Access Theses & Dissertations

Additive manufacturing (AM), now more commonly known as 3D printing, has been classified as efficient, fast, and practical in the prototyping sector of product development. In the work presented here, we will use one of the AM techniques known as Material extrusion 3D printing (ME3DP), which has all the advantages of AM. However, one of the biggest challenges facing ME3DP technologies is the limitation of the range of materials used by this technique. Acrylonitrile butadiene styrene (ABS) and poly-lactic acid (PLA) are currently the most common thermoplastics materials used in ME3DP because of their ability to melt and be reprocessed. …

Alkali-~Activated Fly Ash Binders: Feasibility As A Sustainable Alternative To Ordinary Portland Cement For Pre-~Cast Systems, Kimberly Sierra

UNLV Theses, Dissertations, Professional Papers, and Capstones

Fresh, load-dependent, transport, and durability properties of alkali-activated fly ash mortars were studied. The influences of activator concentration, solution-to-binder ratio, curing condition, activator type, and sodium silicate-to-total solution ratio on the properties of the studied alkali-activated mortars were examined. This study was divided in two phases. The first phase dealt with the use of sodium hydroxide as the sole activator. The second phase of the study was divided into two parts, both of which used a combination of sodium hydroxide and sodium silicate as the activator solution. Part I of phase II used elevated temperature curing conditions, whereas part II …

Sustainable Decolorization Of Reactive And Acid Dye Wastewater Using Photo-Fenton Oxidation Both With And Without Biodegradation: Laboratory And Field Studies, Marissa R. Jablonski

Theses and Dissertations

Photo-Fenton oxidation is an advanced oxidation process (AOP) used to degrade low-concentration textile dye wastewater using expensive chemicals. The technique has shown promise in laboratory-scale projects, but has not been scaled up sustainably to function for industry. Aerobic biodegradation is a common biological treatment method used in large-scale textile industrial applications that generates large amounts of hazardous biological waste. This waste is often left open to the elements and subsequently leaches into natural waterways or onto land. This is the first study of its kind to combine the two to treat cottage-scale industry-grade textile wastewater with a dye concentration of …

Methane Production By A Packed-Bed Anaerobic Digester Fed Dairy Barn Flush Water, Sean Richard Thomson

Master's Theses

Packed-bed digesters are an alternative to covered lagoon digesters for methane production and anaerobic treatment of dilute wastewaters such as dairy barn flush water. The physical media of packed-beds retain biofilms, often allowing increased treatment rates. Previous studies have evaluated several types of media for digestion of dilute wastewaters, but cost and media fouling have setback commercial development. A major operational cost has been effluent recirculation pumping.

In the present effort, a novel approach to anaerobic digestion of flush dairy water was developed at pilot-scale: broken walnut shells were used as a low-cost packed-bed medium and effluent recirculation was replaced …

An Investigation Of Waste Glass-Based Geopolymers Supplemented With Alumina, Mary U. Christiansen

Dissertations, Master's Theses and Master's Reports - Open

An increased consideration of sustainability throughout society has resulted in a surge of research investigating sustainable alternatives to existing construction materials. A new binder system, called a geopolymer, is being investigated to supplement ordinary portland cement (OPC) concrete, which has come under scrutiny because of the CO2 emissions inherent in its production.

Geopolymers are produced from the alkali activation of a powdered aluminosilicate source by an alkaline solution, which results in a dense three-dimensional matrix of tetrahedrally linked aluminosilicates. Geopolymers have shown great potential as a building construction material, offering similar mechanical and durability properties to OPC. Additionally, geopolymers have …

Sustainable Riparian Restoration - The Utilization Of Sewage Effluent To Construct Wetlands Along The Rio Grande: A String Of Pearls Approach To Replenishment, Michael Earl Landis

Open Access Theses & Dissertations

The Rio Grande, from Elephant Butte Dam to El Paso, has been transformed from a free-flowing wild river into a highly engineered irrigation system. The Rio Grande Project, authorized by Congress in 1905, mandated the Bureau of Reclamation to store and deliver water exclusively to farmers. The river, maintained by the International Boundary and Water Commission, has been straightened and channelized between levees. The laws and policies governing the use of the waters of the Rio Grande are prohibitive to ecological restoration. Prior Appropriation doctrine allows for the exclusive use of these waters.

One sustainable tactic for replenishing the denuded …

A Framework For Strategic Sustainable Supply Chain Design, Abril Paola Vazquez

Open Access Theses & Dissertations

Sustainable supply chain management has raised interest considerably in recent years; due to environmental concerns from society as well industries. There is a high interest in the industries to solve this problem but many of the frameworks are directed to specific situation or structure. A strategic sustainable supply chain design framework is presented with the purpose of providing many companies, including small and big industries, the means to maintain an eco-friendly operation. These include; industry plants, distribution centers, and retailers.