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2019

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Articles 1 - 30 of 1770

Full-Text Articles in Civil and Environmental Engineering

Remediating Soil For Successful Vegetation Establishment Along Nebraska Highways, Shad Mills, Martha Mamo, Walt Schacht, Humberto Blanco-Canqui Dec 2019

Remediating Soil For Successful Vegetation Establishment Along Nebraska Highways, Shad Mills, Martha Mamo, Walt Schacht, Humberto Blanco-Canqui

Nebraska Department of Transportation: Research Reports

Vegetation along roadsides is important to prevent soil erosion, provide habitat, and filter water running off the road. Vegetation close to the pavement along highways in Nebraska does not readily establish and persist. It is thought that the sodium and bulk density are the driving factors behind the lack of vegetation. After a construction project the shoulder is seeded into the compacted soil, and during winter salts can accumulate in the soil because of deicing agents being used. The purpose of our study was to determine if the sodium and bulk density are the driving factors of the vegetation cover. …


Land Use/Cover Change And Their Impacts On Streamflow In Kikuletwa Catchment Of Pangani River Basin, Tanzania, Upendo Msovu Dec 2019

Land Use/Cover Change And Their Impacts On Streamflow In Kikuletwa Catchment Of Pangani River Basin, Tanzania, Upendo Msovu

Tanzania Journal of Engineering and Technology (TJET)

Streamflow perturbation is highly prevalent in Kikuletwa catchment. However, little is known concerning land use/cover change (LULCC) with regard to streamflow perturbation in the catchment. This study aims to detect the historical and predict future LULCC and assess their impacts on streamflow amounts using the Soil and Water Assessment Tool (SWAT) model. Supervised classification of Landsat imagery data for 1985, 2000 and 2015 years was done in ERDAS 14 Imagine software. Future prediction of LULCC was done using Module for Land Use Change Evaluation (MOLUSCE) tool, a QGIS plug-in. An accuracy ranging from 79% to 82% was obtained for all …


The Potentials Of Faecal Sludge Treatment Using Local Conditioners In Tanzania: A Review, Doglas Benjamin1 Dec 2019

The Potentials Of Faecal Sludge Treatment Using Local Conditioners In Tanzania: A Review, Doglas Benjamin1

Tanzania Journal of Engineering and Technology (TJET)

Worldwide, every day human beings generate millions of tons of Faecal Sludge (FS), which is rich in water, nutrients, energy, and organic compounds. Yet FS is not being managed in a way that permits us to derive value from its reuse, while at the same time, millions of farmers struggle with depleted soils and lack of water. In most of the developing countries, energy for cooking is mainly derived from cutting of trees, either as wood or charcoal. Resource recovery and reuse from FS can create livelihoods, enhance food security, support green economies, reduce waste and contribute to cost recovery …


Prediction Of Haul Units’ Requirements For The Open Pit Mines Operating Towards Closure, Bartłomiej Skawina Dec 2019

Prediction Of Haul Units’ Requirements For The Open Pit Mines Operating Towards Closure, Bartłomiej Skawina

Tanzania Journal of Engineering and Technology (TJET)

The determination of haul units is one of the important steps in the equipment selection process. The process should aim at minimizing the operational costs and create an optimal match for the haulage system. When open pit mines operating towards closure, reducing the operational costs results in significant gaining, and the savings can be used to implement some of the closure plans. In this paper, the prediction of haul units for an open pit mine which operates towards the final pit limit was analysed using discrete event simulation and multiple linear regressions. The result shows that the changes in production …


Practical Approach For Removal Of Natural Organic Matter And Defluoridation Of Maji Ya Chai River Water: Use Of Acid Pre-Treated Bone Char And Coagulants, Godfrey Mbabaye Dec 2019

Practical Approach For Removal Of Natural Organic Matter And Defluoridation Of Maji Ya Chai River Water: Use Of Acid Pre-Treated Bone Char And Coagulants, Godfrey Mbabaye

Tanzania Journal of Engineering and Technology (TJET)

The removal of natural organic matter (NOM) and fluoride from Maji ya Chai River water (MCRW) using bone char (BC) and coagulants was investigated. Fine BC particles ranging from 0.045 to 0.2 mm were used in a 1 litre half-filled container, stirred at 300 rpm for 60 min followed by addition of a commercial coagulant and allowed to settle for 24 hours to remove NOM. MCRW practicable and affordable defluoridation method for removal of NOM through defluoridation with BC pre-treated with 0.3 N HCl followed by coagulation with Poly-aluminium chloride (PACl) is proposed. Reduction of fluoride from 21 mg/L to …


Reviewing The Potential And Constraints Of Modified Technology Options For Faecal Sludge Management In Dar Es Salaam, Tanzania, Amour Seleman Dec 2019

Reviewing The Potential And Constraints Of Modified Technology Options For Faecal Sludge Management In Dar Es Salaam, Tanzania, Amour Seleman

Tanzania Journal of Engineering and Technology (TJET)

Cities in the developing world face the challenge of safe management of faecal sludge because of rapid population growth that overwhelms the sanitation infrastructure and services. In developing countries, only 50% of faecal sludge (FS) generated is safely managed the remaining portion is haphazardly disposed of in the environment risking public health and environment. In response to the urgent need for safely managed sanitation services, technological options for containment, desludging and transportation of FS are being modified. This paper reviewed current desludging practices and the potential of modified technological options for addressing FSM at containment, desludging, and transportation in Dar …


Establishment Of Wildflower Islands To Enhance Roadside Health And Aesthetics, Walter Schacht, Judy Wu-Smart Dec 2019

Establishment Of Wildflower Islands To Enhance Roadside Health And Aesthetics, Walter Schacht, Judy Wu-Smart

Nebraska Department of Transportation: Research Reports

Wildflowers are crucial in the ecological function of the low-input roadside plant communities in terms of water andnutrient cycling, nutrient inputs such as nitrogen, total plant canopy cover, stand longevity, and provision of habitat for numerous small animals. Further, wildflowers provide critical foraging and nesting resources for birds, insects, and other wildlife. Unfortunately, habitat loss from agricultural and urban development has led to rapid population declines in wild bees and other pollinators across the US, thereby jeopardizing not only food production but also the sustainability of our natural landscapes (Kearns & Inouye, 1997). One way to mitigate wild bee decline …


Assessment Of Groundwater Resources In Siwa Oasis, Western Desert, Egypt, Noha H. Moghazy, Jagath J. Kaluarachchi Dec 2019

Assessment Of Groundwater Resources In Siwa Oasis, Western Desert, Egypt, Noha H. Moghazy, Jagath J. Kaluarachchi

Civil and Environmental Engineering Faculty Publications

One of the major challenges facing Egypt is limited water resources associated with rapid increase in population. In 1960s, Egyptian government started to use groundwater from the Nubian Sandstone Aquifer System (NSAS) in the Western Desert to expand agricultural sector. Siwa Oasis is the focus of this study to assess the efficiency of groundwater use and corresponding impacts from 1980 to 2012. Results show that from 1980 to 1998, withdrawal from poorly designed wells increased rapidly causing an increase in excess water about 336%. The increase of excess water with the usage of poor drainage produced lakes. Remote Sensing showed …


Removel Of Polluntants From Aqueous Solution Via Graphene Oxide/Magnesium Oxide Nanocomposites, Mahdi Heidarizad Dec 2019

Removel Of Polluntants From Aqueous Solution Via Graphene Oxide/Magnesium Oxide Nanocomposites, Mahdi Heidarizad

Civil and Environmental Engineering Theses and Dissertations

In this study, a series of graphene oxide/magnesium oxide nanocomposites (GO/MgO NCs) were synthesized and applied for the removal of Methylene Blue (MB) from aqueous solutions. The prepared NCs were characterized using scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and thermogravimetric analysis. The results showed that MgO particles were successfully layered on GO. The impacts of different experimental variables on the removal of MB including GO/MgO NCs dosage, pH, contact time, and initial MB concentration were investigated.

Thereafter, we investigate the mechanism and kinetics of ozonation processes in the presence of GO/MgO NCs as a catalyst …


Evaluation Of The Mechanisms And Effectiveness Of Nano-Hydroxides, Wood And Dairy Manure-Derived Biochars To Remove Fluoride And Heavy Metals From Water, Anna Rose Wallace, Wenjie Sun Dr, Chunming Su Dr Dec 2019

Evaluation Of The Mechanisms And Effectiveness Of Nano-Hydroxides, Wood And Dairy Manure-Derived Biochars To Remove Fluoride And Heavy Metals From Water, Anna Rose Wallace, Wenjie Sun Dr, Chunming Su Dr

Civil and Environmental Engineering Theses and Dissertations

The development of effective treatment processes for the removal contaminants, such as fluoride and heavy metals, from polluted water have been urgently needed due to serious environmental health and safety concerns. In this dissertation, a variety of materials including various (hydro)oxide nanomaterials, biochars and surface modified biochar were studied to evaluate their effectiveness and mechanism on removing fluoride or mixed heavy metals from water.

In the Chapter 2, this study investigated the adsorptive removal of fluoride from water using various (hydro)oxide nanomaterials, focusing on ferrihydrite, hydroxyapatite (HAP) and brucite, which have the potential to be used as sorbents for surface …


Two Clamped Pipe Support Connections For Oil And Gas Brownfield Projects, Helen M. Claycomb Dec 2019

Two Clamped Pipe Support Connections For Oil And Gas Brownfield Projects, Helen M. Claycomb

LSU New Orleans Theses and Dissertations

In the oil and gas industry, brownfield projects focus on the modification of or addition to an existing production facility that is fully operational and operating. Welding is typically avoided on these projects. The drilling of holes in existing primary structural elements is also prohibited. Clamped connections are often used when adding additional services in a brownfield project. There are different types of clamped connections utilized when a new structural support must be attached to an existing vertical structural pipe. The short bolt clamped connection is a well-established connection and typically used on offshore projects. The U-bolt clamped connection is …


Wintertime Spatial Distribution Of Ammonia And Its Emission Sources In The Great Salt Lake Region, Alexander Moravek, Jennifer G. Murphy, Amy Hrdina, John C. Lin, Christopher Pennell, Alessandro Franchin, Ann M. Middlebrook, Dorothy L. Fibiger, Caroline C. Womack, Erin E. Mcduffie, Randy S. Martin, Kori D. Moore, Munkhbayar Baasandorj, Steven S. Brown Dec 2019

Wintertime Spatial Distribution Of Ammonia And Its Emission Sources In The Great Salt Lake Region, Alexander Moravek, Jennifer G. Murphy, Amy Hrdina, John C. Lin, Christopher Pennell, Alessandro Franchin, Ann M. Middlebrook, Dorothy L. Fibiger, Caroline C. Womack, Erin E. Mcduffie, Randy S. Martin, Kori D. Moore, Munkhbayar Baasandorj, Steven S. Brown

Civil and Environmental Engineering Faculty Publications

Ammonium-containing aerosols are a major component of wintertime air pollution in many densely populated regions around the world. Especially in mountain basins, the formation of persistent cold-air pools (PCAPs) can enhance particulate matter with diameters less than 2.5 µm (PM2.5) to levels above air quality standards. Under these conditions, PM2.5 in the Great Salt Lake region of northern Utah has been shown to be primarily composed of ammonium nitrate; however, its formation processes and sources of its precursors are not fully understood. Hence, it is key to understanding the emission sources of its gas phase precursor, ammonia …


Incorporation Of Unmanned Aerial Vehicle (Uav) Point Cloud Products Into Remote Sensing Evapotranspiration Models, Mahyar Aboutalebi, Alfonso F. Torres-Rua, Mac Mckee, William P. Kustas, Héctor Nieto, Maria Mar Alsina, Alex White, John H. Prueger, Lynn Mckee, Joseph Alfieri, Lawrence E. Hipps, Calvin Coopmans, Nick Dokoozlian Dec 2019

Incorporation Of Unmanned Aerial Vehicle (Uav) Point Cloud Products Into Remote Sensing Evapotranspiration Models, Mahyar Aboutalebi, Alfonso F. Torres-Rua, Mac Mckee, William P. Kustas, Héctor Nieto, Maria Mar Alsina, Alex White, John H. Prueger, Lynn Mckee, Joseph Alfieri, Lawrence E. Hipps, Calvin Coopmans, Nick Dokoozlian

Civil and Environmental Engineering Faculty Publications

In recent years, the deployment of satellites and unmanned aerial vehicles (UAVs) has led to production of enormous amounts of data and to novel data processing and analysis techniques for monitoring crop conditions. One overlooked data source amid these efforts, however, is incorporation of 3D information derived from multi-spectral imagery and photogrammetry algorithms into crop monitoring algorithms. Few studies and algorithms have taken advantage of 3D UAV information in monitoring and assessment of plant conditions. In this study, different aspects of UAV point cloud information for enhancing remote sensing evapotranspiration (ET) models, particularly the Two-Source Energy Balance Model (TSEB), over …


An Analysis Of Energy Consumption And The Use Of Renewables For A Small Drinking Water Treatment Plant, Saria Bukhary, Jacimara Batista, Sajjad Ahmad Dec 2019

An Analysis Of Energy Consumption And The Use Of Renewables For A Small Drinking Water Treatment Plant, Saria Bukhary, Jacimara Batista, Sajjad Ahmad

Civil and Environmental Engineering and Construction Faculty Research

One of the pressing issues currently faced by the water industry is incorporating sustainability considerations into design practice and reducing the carbon emissions of energy-intensive processes. Water treatment, an indispensable step for safeguarding public health, is an energy-intensive process. The purpose of this study was to analyze the energy consumption of an existing drinking water treatment plant (DWTP), then conduct a modeling study for using photovoltaics (PVs) to offset that energy consumption, and thus reduce emissions. The selected plant, located in southwestern United States, treats 0.425 m3 of groundwater per second by utilizing the processes of coagulation, filtration, and disinfection. …


Rheological Models For Non-Newtonian Viscosity Of Modified Asphalt Binders And Mastics, Aboelkasim Diab, Zhanping You, Xuelian Li, Jorge Carvalho Pais, Xu Yang, Siyu Chen Dec 2019

Rheological Models For Non-Newtonian Viscosity Of Modified Asphalt Binders And Mastics, Aboelkasim Diab, Zhanping You, Xuelian Li, Jorge Carvalho Pais, Xu Yang, Siyu Chen

Michigan Tech Publications, Part 1

This paper is aimed at providing a comprehensive experimental work on the viscosity behavior of different modified asphalt binders and mastics, as well as exploring mathematical representations of the results in attempts to predict the viscosity and flow behaviors according to Vinogradov-Malkin and Phillips-Deutsch models. The modified asphalt binders were prepared in the unaged and aged states using styrene-butadienestyrene (SBS), ethylene-vinyl acetate (EVA), and crumb rubber (CR); while the hydrated lime (HL) and fly ash (FA) were selected to produce the binder-filler mastics. To widen the study findings, the additives (polymers, rubber, and fillers) were applied at different possible levels …


Effect Of Recycled Concrete Aggregates On The Long-Term, Elastic, Total Deflection And Strength Of Precast Prestressed Hollow Core Concrete Slabs, Lizeth Marisol Gomez Santana Dec 2019

Effect Of Recycled Concrete Aggregates On The Long-Term, Elastic, Total Deflection And Strength Of Precast Prestressed Hollow Core Concrete Slabs, Lizeth Marisol Gomez Santana

Civil Engineering Theses

Concrete constitutes the largest portion of construction and demolition waste generated each year in the United States. The Environmental Protection Agency (EPA) estimates that the total production of construction and demolition of concrete waste during 2015 was 381.8 million tons. In order to reduce the economic and environmental effects of waste concrete, researchers have begun to incorporate it into concrete mixtures. However, the inherent variability in mechanical properties between RCA sources makes it difficult to quantify the maximum permissible replacement of natural aggregate and the end-result properties of concrete. This project investigates the use of recycled concrete aggregates (RCA) obtained …


Protocol Efficiently Measuring The Swelling Rate Of Hydrogels, Katherine Zhang, Wuxiang Feng, Congrui Jin Dec 2019

Protocol Efficiently Measuring The Swelling Rate Of Hydrogels, Katherine Zhang, Wuxiang Feng, Congrui Jin

Department of Civil and Environmental Engineering: Faculty Publications

Hydrogels are polymeric materials which can swell in water and retain a significant fraction of water within their structure without dissolving in water. Swelling rate is one of the most important properties of hydrogels. To measure the swelling rate, the profile of swelling capacity versus time of a hydrogel sample is obtained by performing free-absorbency capacity measurements at consecutive time intervals. Traditionally, either the tea-bag method, the sieve method, or the filtration method is used for the free-absorbency capacity measurements depending on the amount of the available sample and the desired precision. However, each method has its own systematic drawbacks. …


Concentrations, Sources, And Health Risks Of Particulate Matter In Southeast Us.: Current Status And Future Changes, Fenglin Han Dec 2019

Concentrations, Sources, And Health Risks Of Particulate Matter In Southeast Us.: Current Status And Future Changes, Fenglin Han

LSU Doctoral Dissertations

Evaluation of long-term air quality trends and prediction of future air quality may help to design and demonstrate effectiveness of control strategies and guide future air quality management. As one of the six criteria air pollutants (CAPs) regulated by the US Environmental Protection Agency (EPA), particulate matter with aerodynamic diameter of 2.5 µm or less (PM2.5) is of great interests since it has adverse effects on human health, visibility and climate. This study aims to understand the current status and future changes in concentrations, sources, and health risks of PM2.5 in Southeast US. Firstly, observations were analyzed …


2019 Fall Engr333 Project Final Report, Megan Black, Evan Block, Jacob Deysher, Zach Erickson, Peter Atma, John Macy, Paul Steenwyk, Justin Skaggs, Justin Eekhoff, Adam Marquardt, Alan Samdel, Nathan Van Wyhe, Zach Ashenfelter, Brett Ermer, Clayton Lockwood, Ryan Schierbeek, Andrew Zerull, Matthew Buist, Hannah Chilkiewicz, Nathan Hall, Holly Straup, Ivy Chipinda, Andrew Huston, Peter Oh, Tony Vander Ploeg, Josh Hallenbeck, Cameron Ilbrink, Bridget Pertzsch, Lillie Spackman, Zuber Abdella, Michael Merz, Nathan Schuten, Abigail Willson, William Benneh, Marcus Gelder, Steven Vanast, Tyler Johnson, Christopher Pappageorge, Trevor Sando Dec 2019

2019 Fall Engr333 Project Final Report, Megan Black, Evan Block, Jacob Deysher, Zach Erickson, Peter Atma, John Macy, Paul Steenwyk, Justin Skaggs, Justin Eekhoff, Adam Marquardt, Alan Samdel, Nathan Van Wyhe, Zach Ashenfelter, Brett Ermer, Clayton Lockwood, Ryan Schierbeek, Andrew Zerull, Matthew Buist, Hannah Chilkiewicz, Nathan Hall, Holly Straup, Ivy Chipinda, Andrew Huston, Peter Oh, Tony Vander Ploeg, Josh Hallenbeck, Cameron Ilbrink, Bridget Pertzsch, Lillie Spackman, Zuber Abdella, Michael Merz, Nathan Schuten, Abigail Willson, William Benneh, Marcus Gelder, Steven Vanast, Tyler Johnson, Christopher Pappageorge, Trevor Sando

ENGR 333

Today, many institutions and individuals see energy efficiency as an important issue; reducing energy consumption is thought to decrease demand for fossil fuels and consumes energy more sustainably. However, while more efficient devices can save users both energy and money, they do not always result in less energy use as a society. This discrepancy between expected and actual energy savings is called the rebound effect. This can be a result of several factors: increased use of the device drawing more energy, manufacturers using more energy to create the new device, or money saved by the users being respent in the …


Strengthening Of Corroded Steel Structures Using Cfrp – An Experimental Review, Ghada El-Mahdy Ph.D., P.Eng, Abdallah H. Yassin, Abdel El Rahman Khaled Dec 2019

Strengthening Of Corroded Steel Structures Using Cfrp – An Experimental Review, Ghada El-Mahdy Ph.D., P.Eng, Abdallah H. Yassin, Abdel El Rahman Khaled

Civil Engineering

Fibre reinforced polymers (FRP) have been widely used to strengthen reinforced concrete structures, however, nowadays their use to strengthen steel structures is under investigation. In particular, the need to strengthen corroded steel structures found in aggressive environments, such as marine environments, which have undergone a reduction in cross-sectional area and hence a reduction in their load-carrying capacity is in need of studying. The main problems that arise when using carbon fibre reinforced polymer (CFRP) sheets to strengthen steel structures is the weakness in the interfacial bond between the CFRP and the steel surface, the thinness of CFRP sheet, and the …


Sway And No-Sway Behaviour Of Pitched Roof Portal Frames Composed Of Cold-Formed Steel Sections, Ghada El-Mahdy Ph.D, P.Eng., Maged Tawfick Hanna Ph.D Dec 2019

Sway And No-Sway Behaviour Of Pitched Roof Portal Frames Composed Of Cold-Formed Steel Sections, Ghada El-Mahdy Ph.D, P.Eng., Maged Tawfick Hanna Ph.D

Civil Engineering

Cold-formed sections buckle locally and distortionally in combination with overall buckling of the member. When these sections are incorporated into a portal frame structure, this combination of buckling modes affects the overall buckling behaviour of the portal frame. The objective of this paper is to study the effect of local and distortional buckling on the overall behaviour of portal frames. The portal frames studied have a span of 10 m and an eave height of 3 m with a roof pitch of 1:10. Two frames are studied the first with one intermediate interconnector at the midpoints of the column and …


Human-Infrastructure Interfaces (Hii) Enabled Using Augmented Reality (Ar), Dilendra Maharjan Dec 2019

Human-Infrastructure Interfaces (Hii) Enabled Using Augmented Reality (Ar), Dilendra Maharjan

Civil Engineering ETDs

The modern industrial society is built upon the productivity of advanced computing and agile machines assisting the human workforce to perform their tasks more effectively, accurately and efficiently. The industrial revolution termed as "Industry 4.0" is based on the intelligence of machines working with humans in a collaborative work-space. Contrarily, infrastructure management has relied on the human for making day to day decisions. New emerging technologies can assist during infrastructure inspections, to quantify structural condition with more objective data. However, today's’ owners agree in trusting the inspector's decision in the field over data collected with sensors. If data collected in …


Using Nano- And Micro- Structural Materials For Concrete Environmental Applications, Hala Nabeel Elia Dec 2019

Using Nano- And Micro- Structural Materials For Concrete Environmental Applications, Hala Nabeel Elia

Theses and Dissertations

Utilized globally in the construction industry, concrete is an integral component of homes, roads, airports, skyscrapers, and tunnels. Traditional concrete components are cement, fine aggregate (sand), coarse aggregate (gravel or crushed stone), and water. When cement and water compound together they will make a paste which binds all the aggregates together to make the concrete. Unfortunately, every one ton of cement manufactured emits 0.9 ton of CO2into the air. The goal of this two-part work was to obtain an environmentally friendly concrete. The first part used supplementary cementitious materials (SCM), fly ash and silica fume, to create concrete with high …


Evaluation Of A Novel Remote Displacement Sensor Prototype Using Video And Laser-Based Technology For Civil Infrastructure Applications, Nicholas J. Brown Dec 2019

Evaluation Of A Novel Remote Displacement Sensor Prototype Using Video And Laser-Based Technology For Civil Infrastructure Applications, Nicholas J. Brown

Civil and Environmental Engineering Master's Project Reports

Deflection measurements on structures, especially with regards to long-term monitoring, continues to be a challenge with current sensor technologies. Material degradation and changes in the mechanical properties due to aging (for example, creep and shrinkage in concrete bridges) directly impact the deflections exhibited by a structure. In this article we introduce and discuss the evaluation of a novel laser and video-based displacement sensor prototype to monitor displacements and rotations in structures remotely. The sensor is both inexpensive, using off-the shelf components, but also accurate and practical for situations that do not allow the use of conventional displacement sensors, which require …


In-Plane Vibration Of Hammerhead Resonators For Chemical Sensing Applications, Luke A. Beardslee, Christopher Carron, Kemal S. Demirci, Jonathan Lehman, Steven Schwartz, Isabelle Dufour, Stephen M. Heinrich, Fabien Josse Phd, Oliver Brand Dec 2019

In-Plane Vibration Of Hammerhead Resonators For Chemical Sensing Applications, Luke A. Beardslee, Christopher Carron, Kemal S. Demirci, Jonathan Lehman, Steven Schwartz, Isabelle Dufour, Stephen M. Heinrich, Fabien Josse Phd, Oliver Brand

Civil and Environmental Engineering Faculty Research and Publications

Thermally excited and piezoresistively detected in-plane cantilever resonators have been previously demonstrated for gas- and liquid-phase chemical and biosensing applications. In this work, the hammerhead resonator geometry, consisting of a cantilever beam supporting a wider semicircular “head”, vibrating in an in-plane vibration mode, is shown to be particularly effective for gas-phase sensing with estimated limits of detection in the sub-ppm range for volatile organic compounds. This paper discusses the hammerhead resonator design and the particular advantages of the hammerhead geometry, while also presenting mechanical characterization, optical characterization, and chemical sensing results. These data highlight the distinct advantages of the hammerhead …


Flood Dynamics In The Portland Metropolitan Area, Past, Present, And Future, Lumas Terence Helaire Dec 2019

Flood Dynamics In The Portland Metropolitan Area, Past, Present, And Future, Lumas Terence Helaire

Dissertations and Theses

The Portland area has an extensive flood history since it was founded in 1845. In the late 19th century, the Portland area was prone to flooding from snowmelt freshets (3-6 months duration) and brief winter rain or rain-on-snow events. Since that time the magnitude of spring freshets has been curtailed by 45% due to climate change, flow diversions, and reservoir management. Along with changes in hydrology, the bathymetry of the Lower Columbia River has been altered by the dredging of the navigation channel, diking, and land reclamation. To understand how these changes in hydrology and bathymetry have affected tidal and …


Treatment Of Perchlorate And Multiple Oxyanions: Chemical And Biological Investigations, Mark Elkouz Dec 2019

Treatment Of Perchlorate And Multiple Oxyanions: Chemical And Biological Investigations, Mark Elkouz

UNLV Theses, Dissertations, Professional Papers, and Capstones

Groundwater contamination with oxyanions is an issue that must be addressed for environmental, ecological and societal reasons. Chemical and biological treatment methods of reduction are already known and practiced, but the simultaneous presence of multiple oxyanions can add complicating effects to treatment sequence and efficacy. This research was concerned with the investigation of the chemical reductive treatment of Cr(VI) using both calcium polysulfide (CaSx) and ferrous sulfate (FeSO4), and the biological reductive treatment of chlorate, Cr(VI), nitrate and perchlorate using multiple organic substrates. The chemical treatment phase consisted of initial jar tests, using CaSx and FeSO4, followed by a laboratory …


Examining The Effectiveness Of A 4d Schedule And A Virtual Reality Model On A Modular Project: Unlv Solar Decathlon Case, Rajarshi Ghimire Dec 2019

Examining The Effectiveness Of A 4d Schedule And A Virtual Reality Model On A Modular Project: Unlv Solar Decathlon Case, Rajarshi Ghimire

UNLV Theses, Dissertations, Professional Papers, and Capstones

The use of a 4D schedule as technological advancement has brought significant improvement to the planning and execution of construction projects, through visualizing stepwise construction progress, following a sequence of pre-planned activities, and finalizing a baseline schedule with necessary changes. Moreover, the application of virtual reality (VR) to create interactive 3D models of a planned structure has made it possible to make a detailed planning of any construction project. Because of these benefits, the use of 4D schedules and VR in the construction industry has increased drastically, leading to improved planning and execution. However, past studies have given little attention …


Alkali-Silica Reactivity Of Mortars Containing Natural Pozzolan, Arash Kian Dec 2019

Alkali-Silica Reactivity Of Mortars Containing Natural Pozzolan, Arash Kian

UNLV Theses, Dissertations, Professional Papers, and Capstones

Alkali-silica reactivity is one of the most recognized deleterious phenomena in Portland cement concrete resulting in cracks, spalling, and other deleterious mechanisms.

The aim of this study was (i) to assess the extent of reactivity of the aggregates, quarried from seven different sources, suspected of being conducive to ASR, and (ii) to compare the effectiveness of industrial (Class F fly ash) and natural pozzolans in mitigation of alkali-silica reactivity of the studied aggregates. To this end, seven aggregate sources, four natural pozzolan sources, and one source of Class F fly ash were used. ASTM Type V Portland cement was replaced …


Design Of Efficient Carbon-Based Adsorbents For The Removal Of Organic And Inorganic Water Contaminants, Sayedeh Soroosh Mortazavian Dehkordi Dec 2019

Design Of Efficient Carbon-Based Adsorbents For The Removal Of Organic And Inorganic Water Contaminants, Sayedeh Soroosh Mortazavian Dehkordi

UNLV Theses, Dissertations, Professional Papers, and Capstones

Granular activated carbon (AC) and biochar (BC) are two carbon-based adsorbents commonly used for water and wastewater treatment. However, these adsorbents have drawbacks that suppress their aqueous contaminants removal efficiency. Their major disadvantages are that AC has low selectivity and reusability potential, and BC has a hydrophobic nature.

The scope of this dissertation is to enhance the performance of commonly-used carbon-based adsorbents for the removal of organic and inorganic water contaminants and to understand the interactive mechanism of contaminants’ ions/molecules with adsorbents. Hexavalent chromium (Cr(VI)) and trichloroethylene (TCE) are two types of inorganic and organic water contaminants, respectively, which are …