Digital Commons Network^™

To The Determination Of The Critical Circuit Speed Of The Sharing Drum, Kh. Kh. Igamberdiev, A.B. Mukhitdinov

Irrigation and Melioration

The article is devoted to the theoretical definition of the critical circumferential speed of the stripping drum of a kena harvester, which depends on the drum diameter, diameter and weight of the stems. It was determined from the equality of the change in the momentum of the stem during impact, i.e. from a shock impulse acting on the stem. The shock impulse is determined when the drum blade touches the stem in the process of stripping, which acts on the mass of the entire stem. The duration of the impact of the drum stripping on the stem was determined from …

Development Of An Algorithm For Optimization Of Continuous Technological Process Of Cultivation Of Microorganisms, Sh.R. Rakhmanov

Irrigation and Melioration

In article the analysis of possible modes of microalgae cultivation has been carried out. Two optimization algorithms are substantiated. The first one is based on the method of random search with an absolute bias, an algorithm for optimizing the process of cultivating microorganisms with continuous regeneration of the flow in one cultivator. The second is an algorithm for determining the optimal residence time of chlorella particles in multistage cultivators, focused on the method of dynamic programming, implemented in Wellman's recurrence relation. The developed algorithm for operational forecasting and automatic control of the chlorella cultivation process allows, under given production conditions …

Efficiency Of Using Graphic Software In The Design Of Hydrotechnical Structures, U.A. Nasritdinova, A.M. Khodjaev, Z.I. Kayumova

Irrigation and Melioration

The article examines the work of scientists engaged in research in this area in the design of hydrotechnic structures. The possibilities of design programs for the application of the results of scientific research in the educational process were used. Thanks to the design in these programs, practical tasks are carried out with the utmost precision. The use of computer technology in teaching the subject "Hydrotechnical structures" and the use of graphic software AutoCAD in the design of linear platforms for clothing, curved platforms for clothing from hydrotechnical structures are shown in 2D and 3D three-dimensional modeling.

Analysis Of Tensegrity Structures Using Abaqus, Kayla M. Allen

Honors College Theses

This project involves modeling and analysis of a tensegrity structure using the finite element approach utilizing the Abaqus software package. A tensegrity structure is a special type of assembly consisting of a series of straight solid members, arranged in various geometrical configurations in three-dimensional space and held together by series of cables. The developed finite element models for several tensegrity structures are included in this thesis report to better describe the project.

Feasibility Of Using A High-Power Electromagnetic Energy Harvester To Power Structural Health Monitoring Sensors And Systems In Transportation Infrastructures, Mohsen Amjadian, Anil K. Agrawal, Hani Nassif

Civil Engineering Faculty Publications

This paper investigates the feasibility of an electromagnetism energy harvester (EMEH) for scavenging electric energy from transportation infrastructures and powering of conventional sensors used for their structural health monitoring. The proposed EMEH consists of two stationary layers of three cuboidal permanent magnets (PMs), a rectangular thick aircore copper coil (COIL) attached to the free end of a flexible cantilever beam whose fixed end is firmly attached to the highway bridge oscillating in the vertical motion due to passing traffic. The proposed EMEH utilizes the concept of creating an alternating array of permanent magnets to achieve strong and focused magnetic field …

Understanding The Leaching Mechanism For Lead (Pb) Found In Components Of Locally Manufactured Handpumps In Eastern Madagascar, Nidhi Shah

USF Tampa Graduate Theses and Dissertations

This research sought to determine the lead leaching mechanism impacted by an inorganic scale observed from lead valve weights of the pitcher pump systems used in Tamatave, Madagascar. Based on previous research, these valve weights are considered to be a major source for high lead levels in pump water consumed by the residents. As a part of the study, Raman Spectroscopy, X-ray Fluorescence Spectroscopy (XRF) and Energy Dispersive Spectroscopy with Scanning Electron Microscope (SEM-EDS) were performed to address the objectives of this research. The pump component samples for the analysis were selected based on the amount and visual characteristics of …

The Prospect Of Microwave Heating: Towards A Faster And Deeper Crack Healing In Asphalt Pavement, Shi Xu, Xueyan Liu, Amir Tabakovic, Erik Schlangen

Articles

Microwave heating has been shown to be an effective method of heating asphalt concrete and in turn healing the damage. As such, microwave heating holds great potential in rapid (1–3 min) and effective damage healing, resulting in improvement in the service life, safety, and sustainability of asphalt pavement. This study focused on the microwave healing effect on porous asphalt concrete. Steel wool fibres were incorporated into porous asphalt to improve the microwave heating efficiency, and the optimum microwave heating time was determined. Afterwards, the microwave healing efficiency was evaluated using a semi–circular bending and healing programme. The results show that …

Possibilities Of Using Silicate Rock Powder: An Overview, Claudete Gindri Ramos, James C. Hower, Erika Blanco, Marcos Leandro Silva Oliveira, Suzi Huff Theodoro

Center for Applied Energy Research Faculty and Staff Publications

This study evaluates the on use of crushed rocks (remineralizers) to increase soil fertility levels and which contributed to increase agricultural productivity, recovery of degraded areas, decontamination of water, and carbon sequestration. The use of these geological materials is part of the assumptions of rock technology and, indirectly, facilitates the achievement of sustainable development goals related to soil management, climate change, and the preservation of water resources. Research over the past 50 years on silicate rocks focused on soil fertility management and agricultural productivity. More recently, the combined use with microorganisms and organic correctives have shown positive results to mitigate …

An Analysis Of Suspended Sediment Dynamics In A Partially Mixed Estuary, Riyadh Hamad Muttaleb

Dissertations and Theses

The purpose of this work is to investigate via data analysis and numerical modeling the SPM (suspended particulate matter) dynamics of a heavily contaminated partially urban estuary, the Lower Passaic River estuary (LPR), NJ. Accordingly, I investigate the quantity and mechanics of variation of fine and coarse SPM in the LPR via data analysis. Data analysis focuses on the parameters that affect SPM dynamics at six moored stations occupied during the Fall and Spring seasons, from near the estuary mouth to tidal freshwater. A 3D hydrodynamic model (Delft3D-FM) is used to analyze the effects of estuary topography on the dynamic …

Engineering Students’ Perceptions Of Mathematical Modeling In A Learning Module Centered On A Hydrologic Design Case Study, Madeline F. Merck, Melissa A. Gallagher, Emad Habib, David G. Tarboton

Civil and Environmental Engineering Faculty Publications

Engineering students need to spend time engaging in mathematical modeling tasks to reinforce their learning of mathematics through its application to authentic problems and real world design situations. Technological tools and resources can support this kind of learning engagement. We produced an online module that develops students‚Äô mathematical modeling skills while developing knowledge of the fundamentals of rainfall-runoff processes and engineering design. This study examined how 251 students at two United States universities perceived mathematical modeling as implemented through the online module over a 5-year period. We found, subject to the limitation that these are perceptions from not all students, …

Applications Of Biomimicry In Construction And Architecture: A Bibliometric Analysis, Mugdha Praveen Kshirsagar Mrs, Sanjay Kantrao Kulkarni Dr, Ankush Kumar Meena Mr, Danby Caetano D’Costa Mr, Sushant Sunil Bhavsar Mr

Library Philosophy and Practice (e-journal)

Biomimicry can be considered to be a way of connecting the environment created by man to the natural world. Biomimicry is a science that, as a model, a measure and a tutor, looks to nature. Via site work, construction and everyday operations, biomimicry can be used to enhance the way the built environment is constructed. The main objective of this paper is to perform a bibliometric study of biomimicry-related literature in order to discover the growth of biomimicry as an architectural method in recent years. The time frame considered for this survey is between 1990 and 2020. The findings, however, …

Weather-Related Construction Delays In A Changing Climate: A Systematic State-Of-The-Art Review, Steven J. Schuldt, Matthew R. Nicholson, Yaquarri A. Adams Ii, Justin D. Delorit

Faculty Publications

Adverse weather delays forty-five percent of construction projects worldwide, costing project owners and contractors billions of dollars in additional expenses and lost revenue each year. Additionally, changes in climate are expected to increase the frequency and intensity of weather conditions that cause these construction delays. Researchers have investigated the effect of weather on several aspects of construction. Still, no previous study comprehensively (1) identifies and quantifies the risks weather imposes on construction projects, (2) categorizes modeling and simulation approaches developed, and (3) summarizes mitigation strategies and adaptation techniques to provide best management practices for the construction industry. This paper accomplishes …

Evolving Tides Aggravate Nuisance Flooding Along The U.S. Coastline., Sida Li, Thomas Wahl, Stefan A. Talke, David A. Jay, Philip M. Orton, Xinghui Liang, Guocheng Wang, Lintao Liu

Civil and Environmental Engineering Faculty Publications and Presentations

Nuisance flooding (NF) is defined as minor, nondestructive flooding that causes substantial, accumulating socioeconomic impacts to coastal communities. While sea-level rise is the main driver for the observed increase in NF events in the United States, we show here that secular changes in tides also contribute. An analysis of 40 tidal gauge records from U.S. coasts finds that, at 18 locations, NF increased due to tidal amplification, while decreases in tidal range suppressed NF at 11 locations. Estuaries show the largest changes in NF attributable to tide changes, and these can often be traced to anthropogenic alterations. Limited long-term measurements …

Volcanic Emissions And Atmospheric Pollution: A Study Of Nanoparticles, Erika M. Trejos, Luis F. O. Silva, James C. Hower, Eriko M. M. Flores, Carlos Mario González, Jorge E. Pachón, Beatriz H. Aristizábal

Center for Applied Energy Research Faculty and Staff Publications

The influence of emissions of an active volcano on the composition of nanoparticles and ultrafine road dust was identified in an urban area of the Andes. Although many cities are close to active volcanoes, few studies have evaluated their influence in road dust composition. Air quality in urban areas is significantly affected by non-exhaust emissions (e.g. road dust, brake wear, tire wear), however, natural sources such as volcanoes also impact the chemical composition of the particles. In this study, elements from volcanic emissions such as Si > Al > Fe > Ca > K > Mg, and Si—Al with K were identified as complex hydrates. …

Accelerated Controller Tuning For Wind Turbines Under Multiple Hazards, Aly Mousaad Aly, Milad Rezaee

Faculty Publications

During their lifecycle, wind turbines can be subjected to multiple hazard loads, such as high-intensity wind, earthquake, wave, and mechanical unbalance. Excessive vibrations, due to these loads, can have detrimental effects on energy production, structural lifecycle, and the initial cost of wind turbines. Vibration control by various means, such as passive, active, and semi-active control systems provide crucial solutions to these issues. We developed a novel control theory that enables semi-active controller tuning under the complex structural behavior and inherent system nonlinearity. The proposed theory enables the evaluation of semi-active controllers’ performance of multi-degrees-of-freedom systems, without the need for time-consuming …

An Analysis Of Various Hydrogen Production Methods For Fleet Vehicle Fuel, Eugene J. Denezza Ii

Theses and Dissertations

As conflict, the environment, and politics cause changes around the world, the United States Air Force is pursuing a diversification of drop-in and alternative fuel sources. Hydrogen fuel cells for vehicles are gaining popularity worldwide. Yet, how to best produce hydrogen gas still remains a question. This thesis will provide an overview of various hydrogen production methods and their respective environmental impacts, costs, efficiencies, and viability; and will perform sensitivity analysis to determine an optimal solution. The optimal production method is Thermolysis followed by Steam Reformation of Landfill or Natural Gas, Coal Gasification, and PEM Electrolysis. Based on varying requirements …

Evaluation Of Efficient Water Reuse Technologies For Sustainable Forward Operating Bases, Kelsie L. Crouch

Theses and Dissertations

A secure water source is essential to the resiliency and readiness of military installations and contingency operation locations, especially those located in the dry climates the US military operates in today. There are multiple issues of concern when identifying water sources, such as security, cleanliness, accessibility, and sustainability. Water resources pose a potential vulnerability to mission readiness in a remote, agile environment, such as a forward operating base (FOB). Having a secure water resource helps facilitate mission readiness in the contingency environment, offering the opportunity to be more resilient and cost-effective. Current water treatment technologies present the possibility to perform …

Conversion From Coal To Natural Gas At Wright Patterson Air Force Base: An Analysis And Case Study, Tyler A. Ferry

Theses and Dissertations

Over the last 20 years, natural gas has replaced coal as the preferred fossil fuel for heat and power generation across the United States, due to its increased prevalence, lower cost, and reduced environmental impacts. While most conversion decisions are driven by cost savings, proponents of energy transitions often cite emissions reductions as a tangential benefit. Over the same time, climate change and its impact on the environment and society have come to the forefront of scientific inquiry. One example of the transition from coal to natural gas can be found in Dayton, Ohio. Wright Patterson Air Force Base (WPAFB) …

Fluid Dynamics Modeling For Per- And Polyfluoroalkyl Substances Removal In Legacy Fire Suppression Systems, Jacob G. Spaulding

Theses and Dissertations

Legacy per- and polyfluoroalkyl substances (PFASs) exist in the form of aqueous film-forming foams within hangar fire suppression systems throughout the country, posing a threat to both surrounding environments as well as local populations. The United States (US) Department of Defense (DoD), in conjunction with the US Environmental Protection Agency (EPA), is investigating best practices to flush out existing contaminants prior to disposal and replacement with a less environmentally harmful replacement. While current procedures dictate a triple rinse of the entire system to yield contaminant levels acceptable to the DoD, the practice has never truly been tested. Designed as a …

Climate-Informed Prediction And Forecast Modeling Of Installation Total Energy Consumption, Scott C. Weiss

Theses and Dissertations

Climate variability is an external and stochastic factor that causes energy demand uncertainty. Energy managers can use climate-based models to understand future trends of energy demand and to adjust operations, policy, and budgets accordingly. This research focuses on 1) identifying how climate attributes impact energy use, 2) creating a historically informed statistical modeling framework to skillfully predict energy use, and 3) forecasting future changes to energy use and costs, using CMIP5 temperature projections, at the campus level. After synthesizing the existing breadth of research on climate-informed energy modeling, a skillful, unbiased, climate-informed total energy consumption prediction model is developed for …

Improving Airfield Pavement Degradation Prediction Skill With Local Climate And Traffic, Evan M. Fortney

Theses and Dissertations

Airfield pavements are a critical component of the global transportation network that provide a platform for national defense. Preventative and corrective maintenance activities are founded upon accurate expectations of degradation. The leading pavement management software creates degradation predictions from pavement groups using age as the IV and current state conditions as the DV. For this work, a framework is created and implemented that utilizes a PCR model to build upon accepted practices for degradation modeling to enhance and possibly augment future prediction capabilities. The model was applied to pairs of location and pavement family and reveals several findings: the selected …

Comparing The Environmental Impacts Of Using Mass Timber And Structural Steel, Khang Hoang Nguyen, Steelee Knight Morgan

Construction Management

Although mass timber has seen a gradual rise in demand in the past, there has been a lack of extensive research on the environmental impacts of using mass timber as a primary structural framing material. This paper compares structural steel, and mass timber’s total embodied carbon emissions. Accurate estimates were made using plans and specs for different projects retrieved from semi-structured interviews. The estimates were input through the EC3 Calculator to provide extensive total carbon emissions measurements between each construction material. Using structural steel framing increased the project’s overall environmental impact by roughly 84% compared to using mass timber. The …

Impact Of Multiple Waves Of Covid-19 On Healthcare Networks In The United States, Emad M. Hassan, Hussam N. Mahmoud

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The risk of overwhelming hospitals from multiple waves of COVID-19 is yet to be quantified. Here, we investigate the impact of different scenarios of releasing strong measures implemented around the U.S. on COVID-19 hospitalized cases and the risk of overwhelming the hospitals while considering resources at the county level. We show that multiple waves might cause an unprecedented impact on the hospitals if an increasing number of the population becomes susceptible and/or if the various protective measures are discontinued. Furthermore, we explore the ability of different mitigation strategies in providing considerable relief to hospitals. The results can help planners, policymakers, …

Renewable Energy Generation And Ghg Emission Reduction Potential Of A Satellitewater Reuse Plant By Using Solar Photovoltaics And Anaerobic Digestion, Jonathan R. Bailey, Saria Bukhary, Jacimaria R. Batista, Sajjad Ahmad

Civil and Environmental Engineering and Construction Faculty Research

Wastewater treatment is a very energy-intensive process. The growing population, increased demands for energy and water, and rising pollution levels caused by fossil-fuel-based energy generation, warrants the transition from fossil fuels to renewable energy. This research explored the energy consumption offset of a satellite water reuse plant (WRP) by using solar photovoltaics (PVs) and anaerobic digestion. The analysis was performed for two types of WRPs: conventional (conventional activated sludge system (CAS) bioreactor with secondary clarifiers and dual media filtration) and advanced (bioreactor with membrane filtration (MBR)) treatment satellite WRPs. The associated greenhouse gas (GHG) emissions were also evaluated. For conventional …

Operational Structural Damage Identification Using De-Noised Modal Feature In Machine Learning, Chen Shilei

Student Works (2020-2029)

Structural damage can severely affect the safety and functionality of the structure and lead to economic loss. Vibration-based structural damage detection has raised continuous interest over the decades, as a non-destructive way to provide warnings and predict certain faults at early stages. Compared with conventional modal parameters such as the natural frequency and mode shape, the upstream modal data, namely the frequency response function (FRF), can be a better alternative, because it is rich in modal information and can be easily obtained. However, the FRF is usually measured through experimental modal analysis (EMA) when the test object is in shut-down …

Open-Field Scale-Model Experiments Of Fire Whirls Over L-Shaped Line Fires, Yuto Iga, Kazunori Kuwana, Kozo Sekimoto, Yuji Nakamura

Progress in Scale Modeling, an International Journal

This paper presents the results of open-field scale-model experiments of fire-whirl formation over line fires. L-shaped line fires were burned in crosswinds, and the processes of fire-whirl formation were observed. The flame height was measured using an image-processing technique, while two-dimensional velocity components were measured at two different locations using ultrasonic anemometers. Two tests were selected for comparison: test A, in which intense fire whirls repeatedly formed, and test B, in which no whirls were observed. In test A, the wind flow was bent by the fire plume, creating swirling flows near the burning area, thereby forming fire whirls. On …

Effect Of Reduced Plume Entrainment On The Burning Rate Of Porous Fuel Beds, Sara Mcallister

Progress in Scale Modeling, an International Journal

Large outdoor fires often exhibit unexpected fire behavior, particularly compared with much smaller fires. Understanding the difference between large- and small-scale fires is of importance for both fire behavior predictions and safety. Large fires are often characterized by very tall plumes that can extend to the stratosphere. Particularly as the actively burning area increases, plumes in large-scale fires likely entrain relatively little and may act in a similar fashion to a chimney. To explore the possible changes in burning rate due to the chimney effect, experiments were conducted with wood cribs burned with a chimney of variable height. The burning …

How A Low-Cost Method For Cumulative Water-Sampling Shows Need For Improvement Of Legal Public-Contact Standards In The United States, Samuel C. Kessler

Grawemeyer Colloquium Papers

Across the world, it is estimated that 4.5 billion people live near water sources “impaired” for use or contact. Standards for human-interaction are established by international organizations such as the WHO, and legislative bodies from national to local levels with jurisdiction over the quality of our waterways to ensure public & environmental health. Standards are often assessed from “grab-samples” taken from a waterbody at a certain time, with a minimum number analyzed. Water-quality standards in the United States are enforced under the Clean Water Act (CWA) via the Environmental Protection Agency (EPA), applying to “waters of the United States” (WOTUS). …

Historical Contingency In Microbial Resilience To Hydrologic Perturbations, Hyun-Seob Song, James C. Stegen, Emily B. Graham, Timothy D. Scheibe

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Development of reliable biogeochemical models requires a mechanistic consideration of microbial interactions with hydrology. Microbial response to and its recovery after hydrologic perturbations (i.e., resilience) is a critical component to understand in this regard, but generally difficult to predict because the impacts of future events can be dependent on the history of perturbations (i.e., historical contingency). Fundamental issues underlying this phenomenon include how microbial resilience to hydrologic perturbations is influenced by historical contingency and how their relationships vary depending on the characteristics of microbial functions. To answer these questions, we considered a simple microbial community composed of two species that …

T144, Pingxin Xia, Longtan Shao, Wen Deng

Stress-State Dependency of the Deformation Ratio of Quasi-Elastic Granular Soils under Cyclic Loading -- Raw Data

‘T’ series spreadsheets are the raw data of all tests. (The data in this series are overall stress and strain information).

Supporting information