Engineering Commons^™

Evaluating The Impacts Of Water Conservation Policies On Water Demand, Availability And Outdoor Water Use In The Las Vegas Valley, Kamal Qaiser

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Las Vegas Valley, located in the arid Southern Nevada region, with a growing population, limited water resources, and a prolonged drought, faces a challenge in meeting its future water needs. Southern Nevada Water Authority (SNWA), the main water management agency in the Valley, is focusing on water conservation to reduce water demand. Current water use is 945 lpcd (250 gpcd) which SNWA aims to reduce to 752 lpcd (199 gpcd) by 2035. Presently the indoor outdoor water use proportion is about 40:60 in the Valley. An important component of the Valley's supply are the return flow credits which SNWA …

Investigation Of Potential Pathways And Multi-Cycle Bioregeneration Of Ion-Exchange Resin Laden With Perchlorate, Mohamadali Sharbatmaleki

UNLV Theses, Dissertations, Professional Papers, and Capstones

Ion-exchange (IX) is possibly the most feasible technology for perchlorate removal and perchlorate-selective and non-selective IX resins are commercially available for this purpose. The use of both resins has shortcomings. Selective resins are incinerated after one time use, and non-selective resins produce a regenerant waste stream that contains high concentration of perchlorate. A process involving directly contacting of spent IX resin containing perchlorate with perchlorate-reducing bacteria (PRB) to bioregenerate the resin has been developed and proven recently. In this process PRB biodegrade perchlorate ions which are attached to the functional groups of the resin.

Although its feasibility has been proven, …

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 …

Statistical Modeling And Analysis Of Injury Severity Sustained By Occupants Of Passenger Vehicles Involved In Crashes With Large Trucks, Ahmad Koupaenejad

UNLV Theses, Dissertations, Professional Papers, and Capstones

Crashes are the result of complex interactions between several factors representing driver, roadway, vehicle, and environmental characteristics. Understanding to what degree each factor contributes to the severity of a crash is not a simple task. The outcomes of crashes in the US have been an average of 42,000 deaths and 3 million injuries per year. To better understand the role of significant contributors to crashes, three sets of models using multinomial logit and one using ordered probit were calibrated. To calibrate these models, forty two independent predictor variables including driver/occupants characteristics, crash environment at the crash location, crash characteristics, and …

Seismic Evaluation Of Clark County Critical Bridges Using Nonlinear Static Procedures, Ahmad Said Saad

UNLV Theses, Dissertations, Professional Papers, and Capstones

Bridges are vital connective elements in community transportation systems. In the past, bridges have been severely damaged by earthquakes. However, with proper mitigation techniques, such as bridge retrofit, severe earthquake damage to bridges can be avoided. Since the 1970’s, design codes underwent major changes with regard to seismic analysis and design provisions of structures and bridges. Meanwhile, one third of the nation’s 600,000 inventoried highway bridges are considered as either structurally deficient or functionally obsolete.

This study is a part of the “Earthquakes in Southern Nevada” project. Earlier in this project, buildings and bridges in southern Nevada were studied in …

Mitigation Of Impact Vibrations Using Impedance Mismatch In Cylindrical Structures, Sachiko Sueki

UNLV Theses, Dissertations, Professional Papers, and Capstones

The focus of this work is to study the phenomenon of material impedance mismatch to determine its effect on the mitigation of high frequency accelerations in projectile and long bar structures within linear ranges of materials. In this study, the acceleration responses of structures with various materials and material combinations were studied experimentally, numerically and by the Finite Element Analysis (FEA). Air-gun tests conducted by the US Army Research Laboratory were modeled using FEA to simulate the acceleration pulse and shock waves experienced by artillery components during a launch. After the prototype of projectile was selected, further studies were conducted …

Parametric Study Of Stimulus-Response Behavior Incorporating Vehicle Heterogeneity In Car-Following Models, Saidi Siuhi

UNLV Theses, Dissertations, Professional Papers, and Capstones

The objective of this study was to develop a family of car-following models that address the shortcomings of car-following models developed by General Motors (GM) in the 1950s. The developed models consist of separate models for acceleration, deceleration, and steady-state responses for congested freeway traffic conditions. The study calibrated the models using individual vehicle trajectory data collected on a segment of Interstate 101 in Los Angeles, California. Furthermore, the study validated the models using individual vehicle trajectory data collected on a segment of Interstate 80 in Emeryville, California. The study used nonlinear regression with robust standard errors to estimate the …

Quantity-Based Cost Forecasting System For Street Construction Projects, Nipesh Pradhananga

UNLV Theses, Dissertations, Professional Papers, and Capstones

Construction projects typically are not withdrawn after going into the competitive bidding process. The decision of contracting authorities regarding which projects will proceed to the bidding stage depends, in part, upon the early estimates of probable cost. Efforts are made to make this estimate as realistic as possible. Irrespective of the estimate of probable cost, the actual project cost is established by the amount of the winning bid.

This study analyzed historical bid data of street construction projects undertaken by the Public Works Department, Clark County, Nevada, from 1991 through 2006. The focus of this study was on utilizing statistical …

Analysis Of A Caliche Stiffened Pile Foundation, Richard C. Stone Jr.

UNLV Theses, Dissertations, Professional Papers, and Capstones

Cemented carbonate deposits (known locally as "caliche") in Las Vegas have been used to support shallow and deep foundations with relatively high bearing pressures compared to soil. Most high rise structures in Las Vegas are founded on either a large mat or a long pile foundation. Recently, a new foundation type consisting of a short pile system bonded to shallow cemented layers was utilized for a large high rise building in Las Vegas and settlements during construction were recorded. The bonding of caliche layers together with short piles forms a caliche stiffened pile (CSP) foundation. The CSP foundation is unique …