Engineering Commons^™

Effects Of Aluminium And Tungsten Co-Doping On The Optical Properties Of Vo2 Based Thin Films, Cephas J Lyobha, Nuru R Mlyuka, Margaret E Samiji

Tanzania Journal of Science

Aluminium and tungsten co-doped vanadium dioxide (VO2:W:Al) thin films were deposited by DC reactive magnetron sputtering technique. In this work we report on the effects of aluminium and tungsten co–doping on the optical properties of vanadium dioxide (VO2) based thin films with a view of combining both increased luminous transmittance (Tlum) and lowered transition temperature (τc). The effect of aluminium and tungsten co-doping on semiconductor-metal transition of vanadium dioxide films was investigated and compared with tungsten doped and undopedVO2films. Spectral transmittances of the films were obtained using Shimadzu SolidSpec-3700 DUV UV-VIS-NIR spectrophotometer. The results revealed that the transmittance of tungsten …

Hall Effect Parameters Of Aluminium And Tungsten Co-Doped Vo2 Thin Films, Mohamed Mussa, Nuru R Mlyuka, Margaret E Samiji

Tanzania Journal of Science

The Hall Effect parameters of Al and W co-doped VO2 thin films were studied in order to explain the effect of co-doping on the electrical properties of thermochromic VO2 films. The carrier concentrations and conductivity of the films were found to increase with increase in temperature while carrier mobility decreased reaching a minimum around the transition temperature then slightly rose and became stable at high temperatures. Tungsten doped films displayed higher carrier concentrations and conductivity on both sides of the metal insulator transition and lower mobility compared to undoped and Al and W co-doped VO2 thin films.

Optimization Of Zinc To Tin Ratio In A Sol Gel Precursor Solution On The Growth And Properties Of Annealed Czts Thin Films, Justine John Tibaijuka, Margaret E Samiji, Nuru R Mlyuka

Tanzania Journal of Science

CZTS thin films were deposited by sol–gel spin coating method using precursor solutions prepared by dissolving copper acetate dihydrate, zinc acetate dihydrate, tin chloride and thiourea in methanol and monoethylamine then annealed in RTP furnace at 500 °C. Sol–gel precursor solutions were prepared with different Zn/Sn in a precursor solution and were annealed at different time intervals; and their effects on the optical and electrical properties of CZTS (Cu2ZnSnS4) films were investigated. The optical band-gap values were estimated to be between 1.30 and 1.88 eV while the absorption coefficients were in the range of 104 cm–1 in the visible region. …

Spatial And Temporal Analysis Of Precipitation And Effective Rainfall Using Gauge Observations, Satellite, And Gridded Climate Data For Agricultural Water Management In The Upper Colorado River Basin, Mahyar Aboutalebi, Alfonso F. Torres-Rua, L. Niel Allen

Civil and Environmental Engineering Faculty Publications

Accurate spatial and temporal precipitation estimates are important for hydrological studies of irrigation depletion, net irrigation requirement, natural recharge, and hydrological water balances in defined areas. This analysis supports the verification of water savings (reduced depletion)from deficit irrigation of pastures in the Upper Colorado River Basin. The study area has diverse topography with scattered fields and few precipitation gauges that are not representative of the basin.Gridded precipitation products from TRMM-3B42, PRISM, Daymet, and gauge observations were evaluated on two case studies located in Colorado and Wyoming during the 2014–2016 irrigation seasons. First, the resolution at the farm level is discussed. …

Assessment Of Cooling And Heat Transfer Properties Of Quenchants With Matlab, Lemmy Meekisho, Rosa L. Simencio Otero, Jônatas M. Viscaino, D. Scott Mackenzie, George Totten, Lauralice C.F. Canale

Mechanical and Materials Engineering Faculty Publications and Presentations

There is ongoing interest for evaluating the potential of renewable base stocks, such as vegetable oils, to replace petroleum oils as metal quenchants. Perhaps the most critical part of this process is characterizing and comparing the cooling and heat transfer performance of potential quenchant candidates. In this work, cooling curves of two vegetable oils, palm oil and canola oil, were obtained along with a commercially available conventional and an accelerated petroleum quenchant using the so-called Tensi multiple thermocouple probe, with emphasis on the center probe emulating a small probe concept. The lumped-parameter approach was implemented in the MATLAB environment (Mathworks …

Economic Potential For Distributed Manufacturing Of Adaptive Aids For Arthritis Patients N The U.S., Nicole Gallup, Jennifer Bow, Joshua M. Pearce

Department of Materials Science and Engineering Publications

By 2040, more than a quarter of the U.S. population will have diagnosed arthritic conditions. Adults with arthritis and other rheumatic conditions earn less than average yet have medical care expenditures that are over 12% of average household income. Adaptive aids can help arthritis patients continue to maintain independence and quality of life; however, their high costs limit accessibility for older people and the poor. One method used for consumer price reduction is distributed manufacturing with 3-D printers. In order to assess if such a method would be financially beneficial, this study evaluates the techno-economic viability of distributed manufacturing of …

Quenchant Cooling Curves, Rewetting, And Surface Heat Flux Properties Of Vegetable Oils, Rosa L. Simencio Otero, Jônatas M. Viscaino, Jun Xu, Jianfeng Wu, George Totten, Lauralice C.F. Canale

Mechanical and Materials Engineering Faculty Publications and Presentations

Vegetable oils are currently used for biodegradable and renewable base stocks for quenchant formulation. However, there are relatively few references relating to their true equivalency, or lack thereof, comparative to the quenching performance of petroleum oil-based quenchant formulations. To obtain an overview of the variability vegetable oil quenching performance, the cooling curves and rewetting properties were determined, and the surface heat flux properties were calculated. The vegetable oils that were studied included canola, coconut, corn, cottonseed, palm, peanut, soybean, and sunflower oils. Cooling curves were obtained using the Tensi multiple-surface thermocouple 15 mm diameter by 45 mm cylindrical Inconel 600 …

Effect Of Subsurface Conditions On Flexible Pavement Behavior: Non-Destructive Testing And Mechanistic Analysis, Md. Fazle Rabbi

Boise State University Theses and Dissertations

The behavior of flexible pavements under traffic and environmental loading can be significantly affected by subsurface conditions. Inadequate support conditions under the surface can lead to excessive pavement deformations, often leading to structural and functional failure. This research effort focused on assessing the effects of base/subbase and subgrade layer conditions on flexible pavement behavior. The results of this study are presented in the form of two journal manuscripts.

The first manuscript focuses on utilizing pavement structural and functional evaluation data in making pavement rehabilitation decisions. Visual distress surveys and Falling Weight Deflectometer (FWD) testing are often carried out by agencies …

Foil Thrust Bearing With Pocket Grooves And Tailored Bump Stiffness Distribution For Improved Static Performance, Nguyen Thao Latray

Mechanical and Aerospace Engineering Dissertations - Archive

Gas foil thrust bearing is one of few axial bearing options for high speed turbomachinery systems. Its advantages include low cost, light weight, generous allowance for component mis-alignment and runout. However, the bearing has low load carrying capacity comparing to other types such as rigid gas bearing and magnetic bearing. This work explores two non-traditional design aspects to improve gas foil thrust bearing’s static performance. The bearing bump foil is redesigned to tailor to the bearing pressure profile; hence induces a more uniform gas film thickness. Simulation using independent elastic foundation model predicts the new tailored bump foil thrust bearing …

Integrating Global And Local Forecasting Resources And Methods For Flood Warning Systems In Central America And Caribbean Region, José Fidel Pérez

Theses and Dissertations

Hurricanes and tropical storms occur very frequently in the Central American and Caribbean Region (CA&CR). These extreme weather events produce a lot of rain and consequently a lot of flooding. Damages and loses have been estimated to amount to 13.4 billion dollars in the last ten years. Flood Warning Systems (FEWS) are a key preventive strategy to reduce risk. Technological progress is improving the resources made available for FEWS to be more viable. In spite of the international support for FEWS and the fast development of ICT, there are very few countries in the CA&CR that have succeeded in developing …

Global Renewable And Nonrenewable Energy Use Impact Assessment Of U.S. Manufacturing: An Integrated Cradle-To-Gate Lca And Dea Approach, Bahadir Ezici

Master's Theses

In this thesis, U.S. manufacturing industries` global supply chain-linked energy use and economic output are investigated considering a total of 16 renewable and nonrenewable energy carriers. A multiregion input output (MRIO) framework is employed to conduct the global supply chain-linked energy use impact assessment. The study period was between 1995 and 2014 based on data availability. Thus, 20 MRIO models were developed. Each MRIO model consists of the 40 largest economies of the world and the rest of the world (ROW) as the 41st country. Each country’s economy was structured into 35 manufacturing and service industries based on the Worth …

Variable Rate Irrigation Using A Spatial Evapotranspiration Model With Remote Sensing Imagery And Soil Water Content Measurements, Sandeep Bhatti

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

Variable rate irrigation may help in intensification of agriculture by producing more yield per unit inputs. Real time spatial information about water balance components is important for designing VRI prescription maps. This work involved use of a spatial evapotranspiration model for studying spatial variability in an agricultural field at the Eastern Nebraska Research and Extension Center near Mead, Nebraska. Imagery from unmanned aerial systems and Landsat were used as input for the spatial evapotranspiration model. Other inputs into the model were soil water content measurements from neutron probes, weather data, crop data, previous irrigation prescriptions, and soil properties for the …

A Computational Analysis Of The Gradient Concentration Profile Of Deet And The Mosquito Behavioral Response, Brandon Carver

Master's Theses

DEET is a common active ingredient in most spatial repellents. DEET is also a volatile organic compound. DEET prevents mosquitoes from detecting and coming into contact with an human individual. Gas sensing technologies such as metal oxide semiconductor sensors can detect VOCs. The World Health Organization provides the majority of efficacy testing methods. This research adapts methods from the WHO and use of MOS sensors to further understand how and why DEET affects mosquitos. A custom developed system is used to measure DEET dissipation and observe mosquito behavioral response to the DEET. DEET dissipations and mosquito behavior is measured within …

Comparative Analysis Of Mosquito Trap Counts In The Peruvian Amazon: Effect Of Trap Type And Other Covariates On Counts And Diversity, George W. Peck, Fanny Castro-Llanos, Victor Lopez-Sifuentes, Erica Lindroth

Civil and Environmental Engineering Faculty Publications and Presentations

Efficient detection of multiple species of adult mosquitoes in various habitats using effective traps is a crucial 1st step in any disease prevention program. Novel trap types that target tropical vectors of human diseases require field testing in the habitat of the vector–disease system in question. This paper analyzes a series of mosquito trapping studies conducted at Mapacocha, San Juan Bautista District, Loreto, Peru, during August–September 2013 and April–May 2014. Six trap configurations were evaluated in forest and rural locations. Adult mosquito counts were analyzed using full Bayesian inference of multilevel generalized linear models and posterior probability point estimates of …

Simplified Approach For Structural Evaluation Of Flexible Pavements At The Network Level, Mena Souliman, Stefan Romanoschi, Samer Dessouky

Publications

Currently, there are few available simple procedures to identify structurally weak pavement sections utilizing Falling Weight Deflectometer (FWD) data at the network level (e.g., city, state or province). A simple method is required to determine the structural condition of pavement sections that can be directly implemented and automated in current pavement databases. The objective of this research study is to develop a simple analysis method to determine the structural condition of pavement sections utilizing the currently available non-destructive testing (NDT) deflection measurement devices at the network level that can be directly implemented and automated in the database of a typical …

A Flexible Service-Oriented Approach To Address Hydroinformatic Challenges In Large-Scale Hydrologic Predictions, Michael Antonio Souffront Alcantara

Theses and Dissertations

Water security is defined as a combination of water for achieving our goals as a society, and an acceptable level of water-related risks. Hydrologic modeling can be used to predict streamflow and aid in the decision-making process with the goal of attaining water security. Developed countries usually have their own hydrologic models; however, developing countries often lack hydrologic models due to factors such as the maintenance, computational costs, and technical capacity needed to run models. A global streamflow prediction system (GSPS) would help decrease vulnerabilities in developing countries and fill gaps in areas where no local models exist by providing …

Analyzing Large Workers’ Compensation Claims Using Generalized Linear Models And Monte Carlo Simulation, Fatemeh Davoudi Kakhki, Steven Freeman, Gretchen Mosher

Faculty Publications

Insurance practitioners rely on statistical models to predict future claims in order to provide financial protection. Proper predictive statistical modeling is more challenging when analyzing claims with lower frequency, but high costs. The paper investigated the use of predictive generalized linear models (GLMs) to address this challenge. Workers’ compensation claims with costs equal to or more than US$100,000 were analyzed in agribusiness industries in the Midwest of the USA from 2008 to 2016. Predictive GLMs were built with gamma, Weibull, and lognormal distributions using the lasso penalization method. Monte Carlo simulation models were developed to check the performance of predictive …

Swat Online: Development Of A Web-Based Decision Support System For The Soil And Water Assessment Tool, Spencer Dean Mcdonald

Theses and Dissertations

As satellite and climate modelling technology continues to improve and as climatological disasters and issues continue to impact the global community, climate data will increase in size and relevance. With this new influx of information, it is becoming more and more important for scientists to simply and concisely communicate their findings to both decision makers in governments and disaster preparedness organizations and also to the general public. The Soil and Water Assessment Tool (SWAT) is a powerful modelling tool that allows scientists to simulate essentially all of the physical processes involved in the water cycle. The data that SWAT produces …

Low Temperature Desiccants In Atmospheric Water Generation., Sunil Gupta

Electronic Theses and Dissertations

Surging global water demand as well as changes to weather patterns and over exploitation of natural water sources, such as ground water, has made potable water a critical resource in many parts of the World already – one rapidly heading towards a crisis situation. Desalination has been adopted as a solution – this is however energy intensive and impractical for most of the developing countries - those most in need of water. A renewable source of energy is solar thermal and solar photovoltaic. A plentiful source of water is the humidity in the atmosphere. This research is to push the …

Empathetic Computing For Inclusive Application Design, Kenny Choo Tsu Wei

Dissertations and Theses Collection (Open Access)

The explosive growth of the ecosystem of personal and ambient computing de- vices coupled with the proliferation of high-speed connectivity has enabled ex- tremely powerful and varied mobile computing applications that are used every- where. While such applications have tremendous potential to improve the lives of impaired users, most mobile applications have impoverished designs to be inclusive– lacking support for users with specific disabilities. Mobile app designers today haveinadequate support to design existing classes of apps to support users with specific disabilities, and more so, lack the support to design apps that specifically target these users. One way to resolve …

Design Of A Portable Biogas Purification And Storage System, Anilkumar Kosna

Masters Theses

Biogas is produced from the decomposition of organic materials like manure, sewage sludge or crop fodders in anaerobic digesters. It consists mainly of 40 – 75 % of methane (CH₄), 15 – 60 % of carbon dioxide (CO₂) and trace amounts of other components. The principle constituents of biogas are similar to natural gas. Natural gas has 87 – 97 % of methane (CH₄) and 0.1 – 1 % of carbon dioxide. Natural gas is known to be an alternative fuel with a wide range of applications. The commercial purification technologies exist for large-scale …

Use Of Pv/T Panels To Meet The Building Loads Of Light Commercialized Buildings, Sadhvi Arora

Masters Theses and Doctoral Dissertations

This thesis deals with the analysis of a Photo Voltaic Thermal (PV/T) panel that is capable of producing simultaneously electric power and low-grade heat energy by absorbing the solar energy striking on its surface. A simple mathematical model is developed to estimate the electric power and heat energy gained by the PV/T panel. A water-to-water heat pump is employed that operates by absorbing the low-grade heat energy obtained from PV/T panel, in its evaporator, in order to produce high temperature hot water in its condenser. The high temperature hot water thus produced can be employed to meet the winter heating …

Hidden Curriculum Awareness: A Comparison Of Engineering Faculty, Graduate Students, And Undergraduates, Idalis Villanueva, Marialuisa Di Stefano, Laura Gelles, Katherine Youmans

Engineering Education Faculty Publications

In order for an engineering academic body (e.g., facultyand students) to navigate their surroundings, they must first become aware of the hidden curriculum around them. Hidden curriculum represents how particular assumptions, values, attitudes, and beliefs about schooling manifests in practice. When understood, these types of lessons or messages allow students, faculty, and staff to more easily navigate the academic and socio-political customs needed for success.

As part of a larger study, a total of 224 participants across 57 engineering programs in the United States and Latin America were asked to comment on a survey that asked respondents about the expectations …

Water, Energy, And Carbon Footprints Of Bioethanol From The U.S. And Brazil, Mesfin Mekonnen, Thiago L. Romanelli, Chittaranjan Ray, Arjen Y. Hoekstra, Adam Liska, Christopher M. U. Neale

Adam Liska Papers

Driven by biofuel policies, which aim to reduce greenhouse gas (GHG) emissions and increase domestic energy supply, global production and consumption of bioethanol have doubled between 2007 and 2016, with rapid growth in corn-based bioethanol in the U.S. and sugar cane-based bioethanol in Brazil. Advances in crop yields, energy use efficiency in fertilizer production, biomass-to-ethanol conversion rates, and energy efficiency in ethanol production have improved the energy balance and GHG emission reduction potential of bioethanol. In the current study, the water, energy, and carbon footprints of bioethanol from corn in the U.S. and sugar cane in Brazil were assessed. The …

X-Search: An Open Access Interface For Cross-Cohort Exploration Of The National Sleep Research Resource, Licong Cui, Ningzhou Zeng, Matthew Kim, Remo Mueller, Emily Ruth Hankosky, Susan Redline, Guo-Qiang Zhang

Computer Science Faculty Publications

Background: The National Sleep Research Resource (NSRR) is a large-scale, openly shared, data repository of de-identified, highly curated clinical sleep data from multiple NIH-funded epidemiological studies. Although many data repositories allow users to browse their content, few support fine-grained, cross-cohort query and exploration at study-subject level. We introduce a cross-cohort query and exploration system, called X-search, to enable researchers to query patient cohort counts across a growing number of completed, NIH-funded studies in NSRR and explore the feasibility or likelihood of reusing the data for research studies.

Methods: X-search has been designed as a general framework with two loosely-coupled components: …

Wastewater In Context: Systems-Based Approaches To Improving Wastewater Infrastructure Transitions, Christine Prouty

USF Tampa Graduate Theses and Dissertations

Coastal communities and ecosystems around the world are some of those most vulnerable to the impacts of climate change. In particular, the wastewater treatment systems in these areas are on the forefront of the effects of increasing frequency, duration, and intensity associated with extreme weather events. As such, decision making about adopting new wastewater technologies or transitioning to an improved treatment portfolio is an important area of research for coastal communities because they are critically linked to the health of the nearby aquatic ecosystems (i.e. tourism, fishing, cultural heritage, climate protection).

The decision making process about technology adoption and transitions …

Web-Based Archaeology And Collaborative Research, Fabrizio Galeazzi, Heather Richards-Rissetto

Department of Anthropology: Faculty Publications

While digital technologies have been part of archaeology for more than fifty years, archaeologists still look for more efficient methodologies to integrate digital practices of fieldwork recording with data management, analysis, and ultimately interpretation.This Special Issue of the Journal of Field Archaeology gathers international scholars affiliated with universities, organizations, and commercial enterprises working in the field of Digital Archaeology. Our goal is to offer a discussion to the international academic community and practitioners. While the approach is interdisciplinary, our primary audience remains readers interested in web technology and collaborative platforms in archaeology

“New” Subjects In Mechatronics Management Education, Peter Kopacek

International Journal of Business and Technology

Process – and manufacturing automation as well as robotics are currently one of the fast growing fields in automation. Advanced process control, cyber-physical systems, industry 4.0 and “advanced robots” are no longer a headline. They are in realization. As a consequence of these developments new social, ethical and human questions appear.

Therefore this contribution is a first report about the continuous “modernization” of the Mechatronics Management BSc and MSc programs which are successful running at UBT. Both programs were developed in the framework of two TEMPUS projects from an international consortium from 2006 to 2009. Since that time new “buzzwords” …

Ship-Port Interface : Analysis Of The Cost-Effectiveness Of Cold Ironing At Mombasa Port, Ronald Ssali

World Maritime University Dissertations

No abstract provided.

Biofouling Impacts On The Environment And Ship Energy Efficiency, Adel Ali Desher

World Maritime University Dissertations

No abstract provided.