Engineering Commons^™

Performance Of Nevada’S Aggregates In Alkali-Aggregate Reactivity Of Portland Cement Concrete, Mohammad Shahidul Islam

UNLV Theses, Dissertations, Professional Papers, and Capstones

Alkali-aggregate reaction (AAR) is a form of distress that occurs in concrete and results in serviceability problems, cracks, spalling, and other deterioration mechanisms. There are two categories of AAR, namely, alkali-silica reaction (ASR) and alkali-carbonate reaction (ACR). Alkali-silica reaction is one of the most recognized deleterious phenomena in concrete, and has been a major concern since its discovery in the 1940s. The reaction which occurs between reactive silica or silicates present in some aggregates and alkalis of Portland cement produces an alkali-silica gel that expands in the presence of moisture resulting in concrete cracks. ACR is also a chemical reaction …

Assessment Of Impacts To Hydroclimatology And River Operations Due To Climate Change Over The Colorado River Basin, William Paul Miller

UNLV Theses, Dissertations, Professional Papers, and Capstones

This dissertation investigated the impacts of climate change to the hydroclimatology and river and reservoir management operations within the Colorado River Basin. Preliminary research indicated observed warming trends throughout the Colorado River Basin and corresponding seasonal trends to the magnitude and timing of runoff in the Colorado River Basin. Subsequent research investigated the changing character of precipitation and corresponding impacts to streamflow over the Colorado River Basin. Analysis of snowpack telemetry (SNOTEL) stations over the American West and Colorado River Basin indicated decreasing trends in annual snowpack, often at least at the 95% confidence interval. A shorter snowpack season was …

College Of Engineering Senior Design Competition Spring 2010, University Of Nevada, Las Vegas

Fred and Harriet Cox Senior Design Competition Projects

Each student in his or her senior year chooses, plans, designs, and prototypes a product in this required element of the curriculum. The senior design project encourages the student to use everything learned in the engineering program to create a practical, real-world solution to an engineering challenge.

A highlight of the year-long senior design project is the senior design competition. This competition, which usually takes place the week before finals each semester, helps focus the senior students on increasing the quality and potential for commercial application for their design projects.

Judges from local industry evaluate the projects on innovation, commercial …

A Concise Model Of 3x7 Wire Rope Used In Cable Guardrail Systems, Cody S. Stolle

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Wire rope is a versatile, flexible, high-strength member that is used in many mechanical systems. However, due to the complexity of wire rope, analytical investigations have been relatively limited. Previous attempts to create simplified models of wire rope were not validated with physical testing and used a cumbersome beam-and-shell or beam-and-solid method for simulating the wire rope. An improved LS-DYNA model of 19-mm diameter 3x7 wire rope commonly used in roadside cable guardrail installations has been developed. A Belytschko-Schwer beam element was selected along with material *MAT_166. Since wire rope displays internal damping due to friction of strands and wires, …

Manpower Cost Analysis Of A Distributed En Route Support Structure Versus A Consolidated En Route Support Structure, Phillip M. Rehmert

Theses and Dissertations

The United States military has developed an en route support structure for airlift requirements to deploy and sustain combat forces in conflict. The Air Mobility Command (AMC) is interested in determining the cost effectiveness of two distinctly different en route structures, in particular, the cost effectiveness of one large facility versus supporting combat forces with many smaller facilities. With the current operational tempo, continued analysis must be accomplished to determine if a smaller footprint is possible in the deployment and sustainment scenarios of conflicts seen today; conflicts more centered on a leaner and faster deployment force. This research examines the …

Rebuilding After Disaster - Engineering Lessons From The 2004 Tsunami, Liam Mccarton

Articles

On 26th December 2004 a magnitude 9 earthquake occurred off the west coast of northern Sumatra, Indonesia. The sudden and violent vertical displacement of the sea floor caused a disturbance to the overlying water column, which generated waves (tsunami) that propagated rapidly across the whole of the Indian Ocean. Typically, in open ocean waters, these waves have long wavelengths of the order of 200km and low trough to crest amplitudes. These properties allow them to conserve energy as they propagate over large distances. As the waves enter the shallower waters of coastal areas, their amplitude increases dramatically and their velocity …

On The Turbulent Prandtl Number In Homogeneous Stably Stratified Turbulence, Subhas K. Venayagamoorthy, Derek D. Stretch

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

In this paper, we derive a general relationship for the turbulent Prandtl number Prt for homogeneous stably stratified turbulence from the turbulent kinetic energy and scalar variance equations. A formulation for the turbulent Prandtl number, Prt, is developed in terms of a mixing length scale LM and an overturning length scale LE, the ratio of the mechanical (turbulent kinetic energy) decay time scale TL to scalar decay time scale Tp and the gradient Richardson number Ri. We show that our formulation for Prt is appropriate even for non-stationary (developing) stratified flows, since it does not include the reversible contributions in …

Temporal Biomass Density And Filamentous Bacteria Effects On Secondary Settling, Patricia A. Jones

Civil Engineering ETDs

The activated sludge wastewater treatment process is the most common technology used today and solids separation is a critical and often problematic component of this technology. This leads to requirements for larger clarifiers, increased pumping costs of the diluted settled solids stream, and increased costs for solids treatment. For the past thirty years, the majority of the research in secondary settling problems has focused on the role of filamentous bacteria, and also factors such as floc size and shape. The effects of variable biomass density on settleability of biosolids produced in full scale activated sludge wastewater treatment systems has been …

Slides: Impacts Of Oil Shale On Carbon Emissions, Jeremy Boak

The Promise and Peril of Oil Shale Development (February 5)

Presenter: Dr. Jeremy Boak, Center for Oil Shale Technology & Research, Colorado School of Mines

43 slides

Design And Evaluation Of Steel Bridges With Double Composite Action, Rajan Sen, Steven Stroh, Niranjan Pai, Purvik Patel, Dennis Golabek

Civil and Environmental Engineering Faculty Publications

This report presents findings from a cooperative USF/URS/FDOT research study undertaken to develop design rules for double composite steel bridges. In the study, a 48 ft long, 16 ft wide, 4 ft. 10⅛ in. deep trapezoidal HPS 70W box section designed to AASHTO’s LRFD 2004 specifications was fabricated and tested. The section has an 8 in. thick top slab and a 7 in. thick bottom slab and represented the entire negative moment region of a full-size, continuous bridge. The specimen was tested to evaluate fatigue, service and ultimate provisions of the AASHTO code. Instrumentation was provided to monitor load, strain, …

Use Of Hydroclimatic Forecasts For Improved Water Management In Central Texas , Wenge Wei

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

Accurate seasonal to interannual streamflow forecasts based on climate information are critical for optimal management and operation of water resources systems. Considering most water supply systems are multipurpose, operating these systems to meet increasing demand under the growing stresses of climate variability and climate change, population and economic growth, and environmental concerns could be very challenging. This study was to investigate improvement in water resources systems management through the use of seasonal climate forecasts. Hydrological persistence (streamflow and precipitation) and large-scale recurrent oceanic-atmospheric patterns such as the El Niño/Southern Oscillation (ENSO), Pacific Decadal Oscillation (PDO), North Atlantic Oscillation (NAO), the …

Human And Embodied Energy Analysis Applied To Water Source Protection And Household Water Treatment Interventions Used In Mali, West Africa , R. Brendan Held

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

As water quality interventions are scaled up to meet the Millennium Development Goal of halving the proportion of the population without access to safe drinking water by 2015 there has been much discussion on the merits of household- and source-level interventions. This study furthers the discussion by examining specific interventions through the use of embodied human and material energy. Embodied energy quantifies the total energy required to produce and use an intervention, including all upstream energy transactions. This model uses material quantities and prices to calculate embodied energy using national economic input/output-based models from China, the United States and Mali. …

Development Of Advanced Finite Element Material Models For Cable Barrier Wire Rope, John D. Reid, Karla A. Lechtenberg, Cody S. Stolle

Mid-America Transportation Center: Final Reports and Technical Briefs

An improved LS-DYNA model of ¾-in. (19-mm) diameter 3x7 wire rope commonly used in roadside cable guardrail installations has been developed. A Belytschko-Schwer beam element was selected along with material *MAT_166. Numerical noise was reduced using part stiffness damping with a coefficient of 2%, and frequency range damping with a coefficient of 12%. The optimum element length based on timestep, accuracy, and computational cost was determined to be between 0.4 and 0.8 in. (10-20 mm). Dynamic component tests were conducted on wire rope to determine material properties. These tests were simulated and the results compared to the physical tests. The …

Climate Change Impacts On Water Demand And Salinity In California's Irrigated Agriculture, Gerrit Schoups, Edwin P. Maurer, Jan Hopmans

Civil, Environmental and Sustainable Engineering

This paper examines potential regional-scale impacts of climate change on sustainability of irrigated agriculture, focusing on the western San Joaquin Valley in California. We consider potential changes in irrigation water demand and supply, and quantify impacts on the hydrologic system, soil and groundwater salinity with associated crop yield reductions. Our analysis is based on archived output from General Circulation Model (GCM) climate projections through 2100, which were downscaled to the 1,400 km2 study area. We account for uncertainty in GCM climate projections by considering two different GCM's, each using three greenhouse gas emission scenarios. Significant uncertainty in projected precipitation creates …

The Challenges Of Wastewater Irrigation In Developing Countries, M. Qadir, D. Wichelns, L. Raschid-Sally, Peter G. Mccornick, P. Drechsel, A. Bahri, P. S. Minhas

Daugherty Water for Food Global Institute: Faculty Publications

The volume of wastewater generated by domestic, industrial, and commercial sources has increased with population, urbanization, improved living conditions, and economic development. The productive use of wastewater has also increased, as millions of small-scale farmers in urban and peri-urban areas of developing countries depend on wastewater or wastewater-polluted water sources to irrigate high-value edible crops for urban markets, often as they have no alternative sources of irrigation water. Undesirable constituents in wastewater can harm human health and the environment. Hence, wastewater irrigation is an issue of concern to public agencies responsible for maintaining public health and environmental quality. For diverse …

Considering Sustainability Factors In The Development Project Life-Cycle : A Framework For Increasing Successful Adoption Of Improved Stoves , Travis K. Ostrom

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

Indoor air pollution from combustion of solid fuels is the fifth leading contributor to disease burden in low-income countries. This, and potential to reduce environmental impacts, has resulted in emphasis on use of improved stoves. However, many efforts have failed to meet expectations and effective coverage remains limited. A disconnect exists between technologies, delivery methods, and long-term adoption.

The purpose of this research is to develop a framework to increase long-term success of improved stove projects. The framework integrates sustainability factors into the project life-cycle. It is represented as a matrix and checklist which encourages consideration of social, economic, and …

Post-Project Assessment And Follow-Up Support For Community Managed Rural Water Systems In Panama , Ryu Suzuki

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

The Environmental Health (EH) program of Peace Corps (PC) Panama and a non-governmental organization (NGO) Waterlines have been assisting rural communities in Panama gain access to improved water sources through the practice of community management (CM) model and participatory development. Unfortunately, there is little information available on how a water system is functioning once the construction is complete and the volunteer leaves the community. This is a concern when the recent literature suggests that most communities are not able to indefinitely maintain a rural water system (RWS) without some form of external assistance (Sara and Katz, 1997; Newman et al, …

Comparison Of Indian Ppp Construction Industry And European Ppp Construction Industry: Process, Thresholds And Implementation, Louis Gunnigan, Renuka Rajput

Conference papers

Abstract Since the 1990’s, there has been a rapid rise of Public Private Partnerships (PPPs) across the world. Governments in developing as well as developed countries are increasingly using this procurement method to bridge the much needed infrastructure gap. PPPs are seen as an important tool for producing an accelerated and larger pipeline of infrastructure investments, and catching up with the infrastructure deficit. Arguably, this is why developed and especially developing countries are very keen on PPP models. This paper will compare the PPP procurement process followed in Europe compared to India and presents a thorough review of literature on …

Mineralogy And Leaching Characteristics Of Coal Ash From A Major Brazilian Power Plant, Luis F.O. Silva, Colin R. Ward, James C. Hower, Maria Izquierdo, Frans Waanders, Marcos L.S. Oliveira, Zhongsheng Li, Rachel S. Hatch, Xavier Querol

Coal Combustion and Gasification Products Journal Archive

The feed coals, fly ashes and bottom ashes collected from seven different units in a major Brazilian PF power plant have been subjected to comprehensive mineralogical, geochemical, and petrographic studies, to investigate the links between feed coal and ash characteristics. Ashes from two of the units were collected while the coal was being co-fired with oil as part of the boiler start-up procedure, allowing the impact of oil co-firing on ash characteristics also to be evaluated. High proportions of unburnt carbon and high proportions of retained sulphur were found in the fly ashes produced during oil co-firing, probably reflecting less …

A Survey Of China's Logistics Industry And The Impacts Of Transport Delays On Importers And Exporters, Zeyan Zhang, Miguel Andres Figliozzi

Civil and Environmental Engineering Faculty Publications and Presentations

In the last decades, China?s booming economy has greatly benefited from globalization and trade liberalization. China has found a niche as the world?s manufacturing centre and it is playing a crucial role in a growing number of global supply chains. This research focuses on the performance of international and domestic transport and logistics systems as perceived by Chinese importers and exporters. A broad literature review of Chinese meteoric logistics industry development is provided. Results and analysis of in?depth interviews with Chinese importers and exporters are presented. These interviews provide significant information regarding international freight transport chains, the impact of delays …

Comparison Of Traditional Standard Drainfield With Innovative B&G Treatment Bed For Nutrient Removal From Septic Tank Wastewater, Fahim Hossain

Electronic Theses and Dissertations

Nowadays people are more alert about conservation of water and water scarcity. The amount of usable water is decreasing due to unavailability of pure water for day to day use. Both surface and groundwater is contaminated by untreated wastewater discharged from improper onsite wastewater treatment system, nutrient laden agricultural runoff and increasing use of fertilizer in fields. This elevated nutrient level is increasing the maintenance and operation cost of water treatment plant. So it is an important task to remove those nutrients from wastewater and other water bodies by applying environmental friendly process. In the USA, about 25% homes are …

A Tool To Improve And Preserve Flexible Pavement At Intersections, Carlos Jesus Solis

Open Access Theses & Dissertations

Rural intersections originally constructed with thin untreated flexible base and hot mix or a two-course surface treatment tend to experience severe pushing, shoving and rutting. These failures cause an extremely rough surface that can cause damage to small vehicles and potentially cause motorists to lose control of their vehicles. These distresses almost always result in complete failure of the existing pavement that must be repaired several times during the life of the roadway by maintenance forces. In most cases, pavements constructed with the same materials and cross-sections adjacent to the intersection perform adequately.

The sources of and solutions for failure …

Water Resources, Health, And The Sustainability Of Interventions To Achieve Water And Sanitation Targets Of The Millennium Development Goals In A Changing World, Lauren M. Fry

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

This dissertation addresses sustainability of rapid provision of safe water and sanitation required to meet the Millennium Development Goals. Review of health-related literature and global statistics demonstrates engineers' role in achieving the MDGs. This review is followed by analyses relating to social, environmental, and health aspects of meeting MDG targets.

Analysis of national indicators showed that inadequate investment, poor or nonexistent policies and governance are challenges to global sanitation coverage in addition to lack of financial resources and gender disparity. Although water availability was not found to be a challenge globally, geospatial analysis demonstrated that water availability is a potentially …

Using Virtual Reality To Enhance Electrical Safety And Design In The Built Environment, Martin Barrett, Jonathan Blackledge, Eugene Coyle

Articles

Electricity and the inherent risks associated with its use in the built environment have long since been a priority for the electrical services industry and also the general public who must live and work in this environment. By its nature virtual reality has the advantage of being safe for both the user and equipment. In addition, it offers the user an opportunity to be exposed to a range of scenarios and conditions that either occur infrequently or are hazardous to replicate. This paper presents a prototype desktop virtual reality model, to enhance electrical safety and design in the built environment. …

Diapycnal Diffusivities In Homogeneous Stratified Turbulence, D. D. Stretch, S. K. Venayagamoorthy

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Quantifying diapycnal mixing in stably stratified turbulence is fundamental to the understanding and modeling of geophysical flows. Data of diapycnal mixing from direct numerical simulations of homogeneous stratified turbulence and from grid turbulence experiments, are analyzed to investigate the scaling of the diapycnal diffusivity. In these homogeneous flows the instantaneous diapycnal diffusivity is given exactly by Kd= ∈ρ/ (∂ ρ /∂z)²where ∈ρ is the dissipation rate of density fluctuations, and ∂ ρ /∂z is the mean density gradient. The diffusivity Kd may be expressed in terms of the large-scale properties of the turbulence as K d = γLE …

Calibration Of Hdm-4 For Use In Pavement Management Systems (Pms), Nurdin Mushule

Tanzania Journal of Engineering and Technology (TJET)

One of major problems of road management in developing countries is the lack of decision making tools for preparing road maintenance programmes. This results in poor resource allocation and poor utilisation of existing assets. Pavement management systems (PMS) have been developed around the world in order to assist with the pavement management process in a co-ordinated and systematic manner. Some developed countries have derived pavement performance models that are suited to local conditions by setting up long term pavement performance studies. Conversely, most developing countries do not have the resources required to set up similar large-scale field experiments. However, validation …

Modelling The Impact Of Urbanization On Groundwater Using System Dynamic Technique. A Case Study Of Arusha Municipal Well Field In Northeastern Tanzania, Nimzihirwa Kashimbiri

Tanzania Journal of Engineering and Technology (TJET)

This paper is concerned with the impact of urbanization in aquifer well-system located in the Municipal area of Arusha city, Tanzania. A system dynamic (SD) model was built under VENSIM PLE workbench from twenty-five years (1978-2003) physical and non-physical data to simulate their interactions and relations. This involved use of mathematics ideas and concepts in studying the physical and non – physical components separately, and finally putting them together in new form (model) and study their relations. After model was found to be structurally complete and simulate properly by using the model and unit check tool of VENSIMPLE, parametric calibration …

Applied Climate-Change Analysis: The Climate Wizard Tool, Evan H. Girvetz, Chris Zganjar, George T. Raber, Edwin P. Maurer, Peter Kareiva, Joshua J. Lawler

Civil, Environmental and Sustainable Engineering

Background: Although the message of ‘‘global climate change’’ is catalyzing international action, it is local and regional changes that directly affect people and ecosystems and are of immediate concern to scientists, managers, and policy makers. A major barrier preventing informed climate-change adaptation planning is the difficulty accessing, analyzing, and interpreting climate-change information. To address this problem, we developed a powerful, yet easy to use, web-based tool called Climate Wizard (http://ClimateWizard.org) that provides non-climate specialists with simple analyses and innovative graphical depictions for conveying how climate has and is projected to change within specific geographic areas throughout the world. Methodology/Principal Findings: …

Identifying And Comparing Key Process Attributes For Sustainable Building Delivery In India And The U.S., Prashanth Palanisamy

All Theses

India is a rapidly developing nation with the associated brisk pace of construction. More sustainable building practices for construction in India would have social, environmental, and economic benefits. However, the key process attributes for successfully planning, designing, and constructing sustainable buildings in India are largely undefined. Other projects in India would benefit from a rigorous identification of these key process attributes which could help leapfrogging the sustainable building delivery in India to the best available practices.
Sustainable buildings require different delivery processes than traditional buildings; this can lead to process wastes due to unfamiliarity or incompatibility of the processes. These …

An Improved Cube Cell Assembly For The Use With High Pressure/High Temperature Cubic Apparatus In Manufacturing Polycrystalline Diamond Compact Inserts, Kevin Christian Bach

Theses and Dissertations

The goal for this research was to reduce the current manufacturing cost of the polycrystalline diamond compact (PDC) inserts utilized in the natural gas and oil drilling industry while not reducing their current performance. Polycrystalline Diamond is added to the tungsten-carbide (WC) substrates commonly utilized in these applications because of its greater wear and thermal resistance. With the current cube cell design for the high-pressure/high-temperature apparatus, it is necessary to bond an extra WC substrate to the polycrystalline diamond insert to achieve the sizes generally ordered by the customers. The problem of bonding the extra WC substrate was solved by …