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Full-Text Articles in Engineering

Influence Of Technological Parameters On The Chemical Composition Of Calcium Polyphosphates From Phosphorites Central Kyzylkum, Ulugberdieva Ziyada, Khujamberdiev Sherzod, Mirzakulov Kholtura, Usmanov Ilkham Apr 2020

Influence Of Technological Parameters On The Chemical Composition Of Calcium Polyphosphates From Phosphorites Central Kyzylkum, Ulugberdieva Ziyada, Khujamberdiev Sherzod, Mirzakulov Kholtura, Usmanov Ilkham

CHEMISTRY AND CHEMICAL ENGINEERING

The aim of the research was to study the effect of temperature, the ratio of P2O5EPA:P2O5PRM and the duration of calcination on the content of various forms of P2O5 in calcium polyphosphate. The effect of calcination temperature from 150 to 300 °C, the ratio of P2O5EPA:P2O5FRM from 2,15 to 4,50 and the duration of the process from 20 to 120 minutes on the changes in various forms of P2O5 were studied. It was shown that with increasing temperature to 200-250 °C the content of the total (ortho + poly) assimilable form of Р2О5 increases and then decreases ...


Esophageal Temperature Mapping And Monitoring Sheath, Nicole M. Rogers, Hillary Johnson, Alexander Silva Mar 2020

Esophageal Temperature Mapping And Monitoring Sheath, Nicole M. Rogers, Hillary Johnson, Alexander Silva

Biomedical Engineering

The purpose of this document is to provide a product development summary for an accessory device that joins an esophageal temperature probe and a mapping catheter together to be used during cardiac ablation. Catheter ablation therapy is performed in the left atrium, utilizing extremely hot or cold temperatures to create scar tissue and treat atrial fibrillation and other arrhythmias. The close positioning of the left atria adjacent to the esophagus presents a large risk as the extreme temperatures used during ablation can lead to esophageal damage or fistulas. This device is designed to integrate correlate data from the temperature probe ...


Room Management Web Application And Movement And Temperature Sensors, Visalbotr Chan, Huy Anh Duong Mar 2020

Room Management Web Application And Movement And Temperature Sensors, Visalbotr Chan, Huy Anh Duong

Computer Engineering

There are three main parts of this system: micro-controller, database, and website. Micro-controller detects motion of people walking in and out and It also measures room temperature and humidity in a confined space then updates collected data to the database. Our system’s database contains 6 main columns: room number, room capacity, number of students, temperature in Celsius, humidity in percent and date created. Finally, this database is queried by the website to display the information on the webpage. Users could also navigate on our site to check the most and least occupy rooms, and they can also search for ...


Field Assessment Of Interreplicate Variability From Eight Electromagnetic Soil Moisture Sensors, Tsz Him Lo, Daran Rudnick, Jasreman Singh, Hope Njuki Nakabuye, Abia Katimbo, Derek M. Heeren, Yufeng Ge Jan 2020

Field Assessment Of Interreplicate Variability From Eight Electromagnetic Soil Moisture Sensors, Tsz Him Lo, Daran Rudnick, Jasreman Singh, Hope Njuki Nakabuye, Abia Katimbo, Derek M. Heeren, Yufeng Ge

Biological Systems Engineering: Papers and Publications

Interreplicate variability—the spread in output values among units of the same sensor subjected to essentially the same condition—can be a major source of uncertainty in sensor data. To investigate the interreplicate variability among eight electromagnetic soil moisture sensors through a field study, eight units of TDR315, CS616, CS655, HydraProbe2, EC5, 5TE, and Teros12 were installed at a depth of 0.30 m within 3 m of each other, whereas three units of AquaSpy Vector Probe were installed within 3 m of each other. The magnitude of interreplicate variability in volumetric water content (θv) was generally similar between ...


Caracterización De La Variabilidad Del Recurso Eólico, Sergio Stiven Salamanca Forero Jan 2020

Caracterización De La Variabilidad Del Recurso Eólico, Sergio Stiven Salamanca Forero

Ingeniería Eléctrica

La generación de energía eléctrica a partir de fuentes renovables ha significado uno de los mayores avances tecnológicos en las últimas décadas, esto gracias a su aporte para disminuir la contaminación que se produce utilizando combustibles fósiles como fuente principal y además ofrecer un soporte en materia de seguridad energética. La tendencia de utilizar cada vez más alternativas de generación con energías renovables se encuentra en crecimiento permanente y por esto resulta de vital importancia estudiar más este campo para así lograr facilitar la integración de estas en la red actual.

En el presente trabajo se centra en un tipo ...


Effect Of Blending Amaranth Grain With Maize Kernels On Maize Weevil Control During Storage, Denis Bbosa, Thomas J. Brumm, Carl J. Bern, Kurt A. Rosentrater, D. Raj Raman Jan 2020

Effect Of Blending Amaranth Grain With Maize Kernels On Maize Weevil Control During Storage, Denis Bbosa, Thomas J. Brumm, Carl J. Bern, Kurt A. Rosentrater, D. Raj Raman

Agricultural and Biosystems Engineering Publications

Amaranth (Amaranthus spp.) is used as a vegetable, food, forage, and sometimes an ornamental. Amaranth grain has higher protein content than other cereals, making it a good choice for human consumption. Maize is among the three most widely grown grains in the world, but it can experience large postharvest losses during storage due to infestation by the maize weevil (Sitophilus zeamais). Due to the small size of amaranth seeds, this study postulated that amaranth grain can be blended with maize during storage to fill the intergranular spaces between maize kernels, reducing the overall void volume to minimize maize weevil movements ...


Establishment Of A Numerical Model For Sulfate Attacked Concrete Considering Multi-Factors, Shanshan Qin, Dujian Zou, Jun Jiang, Tiejun Liu Nov 2019

Establishment Of A Numerical Model For Sulfate Attacked Concrete Considering Multi-Factors, Shanshan Qin, Dujian Zou, Jun Jiang, Tiejun Liu

International Conference on Durability of Concrete Structures

Sulfate attack is one of the major durability problems of concrete structures, which is manifested by expansive cracks and deterioration of cement paste. In this study, a numerical model is proposed to predict the process of ionic diffusion into concrete under external sulfate attack. The chemical reaction and diffusion processes are considered in this model. Furthermore, the influence of calcium leaching, chemical activity of multi-ions, temperature and changes in porosity are also taken into account. The initial porosity and tortuosity are assumed to be homogeneous in concrete, and the chemical potential gradient is regarded as the driving force for ions ...


Effects Of Temperature And Curing Duration On The Stability Of Slag Cements In Combined Chloride-Sulphate Environments, Joseph Onah Ukpata, P. A. M. Basheer, Leon Black Nov 2019

Effects Of Temperature And Curing Duration On The Stability Of Slag Cements In Combined Chloride-Sulphate Environments, Joseph Onah Ukpata, P. A. M. Basheer, Leon Black

International Conference on Durability of Concrete Structures

This experimental study investigates the effects of temperature and curing duration on the stability of slag blended cement systems exposed at 20 °C and 38 °C to combined sodium chloride (30 g/L) – sodium sulphate (3 g/L) solutions. Two slags, designated as slag 1 and 2, having CaO/SiO2 ratios of 1.05 and 0.94, were respectively blended with Portland cement CEM I 52.5R at 30 wt.% replacement level. Mortar prisms and cubes with w/b ratio of 0.5 and binder/aggregate ratio of 1:3 were then prepared for length and mass changes. The ...


Analysis Of Characteristics Of Parabolic And Parabolocylindrical Hubs, Comparison Of Data Obtained On Them, J.R. Kodirov, S.Sh. Khakimova, Sh.M. Mirzaev Aug 2019

Analysis Of Characteristics Of Parabolic And Parabolocylindrical Hubs, Comparison Of Data Obtained On Them, J.R. Kodirov, S.Sh. Khakimova, Sh.M. Mirzaev

Journal of Tashkent Institute of Railway Engineers

Solar energy technologies can be quickly deployed and have the potential for a global transfer of technology and innovation. In order to manufacture parabolic and parabolic cylindrical concentrators, an analytical review of these two types of solar devices was carried out and, after their creation, experiments were conducted on them in the season of maximum solar radiation. The article also presents data and their comparison for planning subsequent actions of research activities.


Design And Feasibility Of A Novel Sprinkler Control Algorithm For Swine Heat Stress Alleviation, Brett C. Ramirez, Steven J. Hoff, Jay D. Harmon Aug 2019

Design And Feasibility Of A Novel Sprinkler Control Algorithm For Swine Heat Stress Alleviation, Brett C. Ramirez, Steven J. Hoff, Jay D. Harmon

Brett Ramirez

No abstract provided.


Impact Of Cycloalkanes On Ignition Propensity Measured As Derived Cetane Number In Multi-Component Surrogate Mixtures, Dalton Odell Carpenter Jul 2019

Impact Of Cycloalkanes On Ignition Propensity Measured As Derived Cetane Number In Multi-Component Surrogate Mixtures, Dalton Odell Carpenter

Theses and Dissertations

Cycloalkanes are one type of hydrocarbons present in real jet fuels. The distinct cyclic structure of the cyclo-alkanes impacts the chemical kinetic behavior differently compared to n- and iso-alkanes. At high temperatures, thermal decomposition reactions dominate, producing n-alkyl radicals similar to the oxidation reactions of n-alkanes thus promoting the reactivity. Whereas in low temperatures, the presence of the ring structure essentially suppresses the formation of alkylhydroperoxy radicals (QOOH) from alkylperoxy radicals (RO2), thus exhibiting similar reactivity to iso-alkanes. In previous generations of surrogate fuels, the cyclo-alkane functional group were largely ignored due to low levels of cycloalkanes in traditional jet ...


Multi-Resolution Spatio-Temporal Change Analyses Of Hydro-Climatological Variables In Association With Large-Scale Oceanic-Atmospheric Climate Signals, Kazi Ali Tamaddun May 2019

Multi-Resolution Spatio-Temporal Change Analyses Of Hydro-Climatological Variables In Association With Large-Scale Oceanic-Atmospheric Climate Signals, Kazi Ali Tamaddun

UNLV Theses, Dissertations, Professional Papers, and Capstones

The primary objective of the work presented in this dissertation was to evaluate the change patterns, i.e., a gradual change known as the trend, and an abrupt change known as the shift, of multiple hydro-climatological variables, namely, streamflow, snow water equivalent (SWE), temperature, precipitation, and potential evapotranspiration (PET), in association with the large-scale oceanic-atmospheric climate signals. Moreover, both observed datasets and modeled simulations were used to evaluate such change patterns to assess the efficacy of the modeled datasets in emulating the observed trends and shifts under the influence of uncertainties and inconsistencies. A secondary objective of this study was ...


Using A Balloon-Launched Unmanned Glider To Validate Real-Time Wrf Modeling, Travis J. Schuyler, S. M. Iman Gohari, Gary Pundsack, Donald Berchoff, Marcelo I. Guzman Apr 2019

Using A Balloon-Launched Unmanned Glider To Validate Real-Time Wrf Modeling, Travis J. Schuyler, S. M. Iman Gohari, Gary Pundsack, Donald Berchoff, Marcelo I. Guzman

Chemistry Faculty Publications

The use of small unmanned aerial systems (sUAS) for meteorological measurements has expanded significantly in recent years. SUAS are efficient platforms for collecting data with high resolution in both space and time, providing opportunities for enhanced atmospheric sampling. Furthermore, advances in mesoscale weather research and forecasting (WRF) modeling and graphical processing unit (GPU) computing have enabled high resolution weather modeling. In this manuscript, a balloon-launched unmanned glider, complete with a suite of sensors to measure atmospheric temperature, pressure, and relative humidity, is deployed for validation of real-time weather models. This work demonstrates the usefulness of sUAS for validating and improving ...


Analysis Of The Spatial And Temporal Distribution Of Process Gases Within Municipal Biowaste Compost, Sylwia Stegenta, Karolina Sobieraj, Grzegorz Pilarski, Jacek A. Koziel, Andrzej Białowiec Apr 2019

Analysis Of The Spatial And Temporal Distribution Of Process Gases Within Municipal Biowaste Compost, Sylwia Stegenta, Karolina Sobieraj, Grzegorz Pilarski, Jacek A. Koziel, Andrzej Białowiec

Agricultural and Biosystems Engineering Publications

Composting processes reduce the weight and volume of biowaste and produce products that can be used in agriculture (e.g., as fertilizer). Despite the benefits of composting, there are also problems such as odors and the emission of pollutants into the atmosphere. This research aimed to investigate the phenomenon of process gas (CO, CO2, NO, O2) evolution within a large-scale municipal composter. The effects of turning frequency and pile location (outdoor vs. indoors) on process gas and temperature spatial and temporal evolution were studied in six piles (37‒81 tons of initial weight) over a six-month period. The ...


Future Changes Of Hydroclimatic Extremes In Western North America Using A Large Ensemble: The Role Of Internal Variability, Mohammad Hasan Mahmoudi Apr 2019

Future Changes Of Hydroclimatic Extremes In Western North America Using A Large Ensemble: The Role Of Internal Variability, Mohammad Hasan Mahmoudi

Electronic Thesis and Dissertation Repository

Increases in the intensity and frequency of extreme events in Western North America (WNA) can cause significant socioeconomic problems and threaten existing infrastructure. In this study we analyze the impacts of climate change on hydroclimatic extremes and assess the role of internal variability over WNA, which collectively drain an area of about 1 million km2. We used gridded observations and downscaled precipitation, maximum and minimum temperature from seven General Circulation Models (GCMs) that participated in the Coupled Model Intercomparison Project Phase 5 (CMIP5) and a large ensemble of CanESM2 model simulations (CanESM2-LE; 50 members) for this analysis. Spatial and ...


Analysis Of Adhesive Anchorage Systems Under Extreme In-Service Temperature Conditions, Rachel Wang Mar 2019

Analysis Of Adhesive Anchorage Systems Under Extreme In-Service Temperature Conditions, Rachel Wang

Masters Theses

Adhesive anchorage systems have found widespread use in structural applications, including bridge widening, concrete repair and rehabilitation, and barrier retrofitting. Because these applications typically require adhesive anchorage systems to be installed outdoors, the effects of climate conditions and day-to-day temperature fluctuations on adhesive behavior and performance should be considered. The purpose of this thesis is to simulate pullout tests of adhesive anchorage systems for threaded rod and reinforcing bars and to emulate effects under various temperature conditions through the use of finite element analysis. Results from the finite element simulation are then compared to the physical tests conducted at UMass ...


The Effect Of Cryogenic Thermal Cycling On Aging, Rejuvenation, And Mechanical Properties Of Metallic Glasses, Nikolai V. Priezjev Jan 2019

The Effect Of Cryogenic Thermal Cycling On Aging, Rejuvenation, And Mechanical Properties Of Metallic Glasses, Nikolai V. Priezjev

Mechanical and Materials Engineering Faculty Publications

The structural relaxation, potential energy states, and mechanical properties of a model glass subjected to thermal cycling are investigated using molecular dynamics simulations. We study a non-additive binary mixture which is annealed with different cooling rates from the liquid phase to a low temperature well below the glass transition. The thermal treatment is applied by repeatedly heating and cooling the system at constant pressure, thus temporarily inducing internal stresses upon thermal expansion. We find that poorly annealed glasses are relocated to progressively lower levels of potential energy over consecutive cycles, whereas well annealed glasses can be rejuvenated at sufficiently large ...


Efecto De La Inclusión De Residuo De Tóner En Las Propiedades Mecánicas, Físicas Y Químicas De La Pasta De Cemento, Jorge Andrés Iriarte Chacón, Johan Steve Montenegro Guevara Jan 2019

Efecto De La Inclusión De Residuo De Tóner En Las Propiedades Mecánicas, Físicas Y Químicas De La Pasta De Cemento, Jorge Andrés Iriarte Chacón, Johan Steve Montenegro Guevara

Ingeniería Civil

La investigación e implementación de residuos industriales o de uso general en el sector de la construcción, es un tema de estudio que se ha abordado por más de 40 años, tiempo en el cual se han investigado diversos materiales o residuos de los mismos, buscando darles un uso óptimo, para que de esta forma disminuyan su huella ambiental y contribuyan de alguna forma en la construcción de obras civiles, siendo esta una de las mejores alternativas ya que el cemento es uno de los materiales con más usos en campo, además que aportaría a la reducción de costos del ...


Generator Design: A Study Of Optimized Airflow, Rachel Wattleworth Jan 2019

Generator Design: A Study Of Optimized Airflow, Rachel Wattleworth

Williams Honors College, Honors Research Projects

The core goal of this project was to prototype, test, and evaluate a new type of fan for the Safran Electrical & Power air-cooled generators. The idea of a new fan being made for these two generators arose when they were not adhering to design requirements. A base mixed-flow fan was created to test on multiple generators. Upon creating a prototype, it will be tested to prove if it can increase the air flow, decrease temperatures, and increase power and life of the machines. They all proved to be successful and achieve the main objectives for this project. Data such as ...


Droplet Coalescence In An Emulsion To Support Process Scale-Up Of A Topical Ointment, Arya Ketabchi Haghighat Jan 2019

Droplet Coalescence In An Emulsion To Support Process Scale-Up Of A Topical Ointment, Arya Ketabchi Haghighat

Graduate Theses and Dissertations

The stability of a topical ointment primarily consisting of an emulsion of propylene glycol droplets dispersed in a continuous white petrolatum medium was studied using optical methods to monitor droplet size growth and phase separation when the ointment undergoes heating or fluid shear. To investigate the effects of shear, ointment at 32C was sheared using a transparent narrow-gap temperature-controlled Couette flow apparatus operated under laminar flow conditions and that provided approximately uniform shear rates. Optical microscopy was used to obtain time-dependent in-situ propylene glycol droplet size distributions, while simultaneously a wide-field lens and camera were used to detect gross ...


Agenator: An Open Source Computer-Controlled Dry Aging System For Beef, Soon Kiat Lau, Felipe Azevedo Ribeiro, Jeyamkondan Subbiah, Chris R. Calkins Jan 2019

Agenator: An Open Source Computer-Controlled Dry Aging System For Beef, Soon Kiat Lau, Felipe Azevedo Ribeiro, Jeyamkondan Subbiah, Chris R. Calkins

Biological Systems Engineering: Papers and Publications

Dry aging of beef is a process where beef is exposed to a controlled environment with the ultimate goal of drying the beef to improve its quality and value. Comprehensive investigations into the effects of various environmental conditions on dry aging are crucial for understanding and optimizing the process, but the lack of affordable equipment focused on data collection makes it difficult to do so. The Agenator was thus developed as an open source system with a suite of features for investigating dry aging such as: measuring and recording relative humidity, temperature, mass, air velocity, and fan rotational speed; precise ...


Short Beam Shear Strength Evaluations Of Gfrp Composites: Correlations Through Accelerated And Natural Aging, William Todd Barker Jan 2019

Short Beam Shear Strength Evaluations Of Gfrp Composites: Correlations Through Accelerated And Natural Aging, William Todd Barker

Graduate Theses, Dissertations, and Problem Reports

Fiber Reinforced Polymers (FRP) composites have been materials of interest in replacing or reinforcing steel, wood, and concrete, but lack of understanding of degradation under physical and chemical aging is a main concern. Through many years of research, the understanding of aging or durability of GFRPs has improved. To be able to evaluate aging related degradation rates, an accelerated aging methodology under varying environments is introduced. Accelerated aging is a concept used to age composites in a lab controlled environment under varying pH conditions (2 to 13) and temperatures (~ -20° to +160°F). Once acceleratedly aged testing is completed, Arrhenius ...


Elevated Temperature Progressive Damage And Failure Of Duplex Stainless Steel, Darren P. Luke Dec 2018

Elevated Temperature Progressive Damage And Failure Of Duplex Stainless Steel, Darren P. Luke

Civil Engineering ETDs

Ductile failure of metals has been the focus of research efforts within academia and industry for many years since it is tremendously important for understanding the failure of structures under extreme loading conditions. However, limited research has been dedicated to elevated temperature ductile failure, which is critical for evaluating catastrophic events such as industrial, structural or shipping vessel fires. A detailed investigation was conducted on the structural response of Duplex Stainless Steel at elevated temperatures. The temperature dependence of elastic modulus, yield strength, ultimate strength, and ductility was measured up to 1000°C and a continuum damage plasticity model was ...


Experimental Testing And Modeling Of Partial Nitrification At Different Temperatures, Xiaoguang Liu Dec 2018

Experimental Testing And Modeling Of Partial Nitrification At Different Temperatures, Xiaoguang Liu

Electronic Thesis and Dissertation Repository

Nitrogen in wastewater treatment plant effluents has adverse environmental effects on aquatic systems. Excessive concentrations of nitrogen in water bodies can result in the depletion of dissolved oxygen, deterioration of water quality, and shifts of biotic community. Conventional biological nitrogen removal (BNR) processes consume high energy for nitrification and require external carbon for denitrification. Alternatively, partial nitrification is of interest as an emerging technology for its lower need of organic carbon addition and cost savings in aeration. In this study, the main objectives are: 1- developing a mathematical model involving operational parameters for the determination of successful partial nitrification conditions ...


Duty-Cycle Based Physical Unclonable Functions (Pufs) For Hardware Security Applications, Mahmood Javed Azhar Nov 2018

Duty-Cycle Based Physical Unclonable Functions (Pufs) For Hardware Security Applications, Mahmood Javed Azhar

Graduate Theses and Dissertations

Duty cycle and frequency are important characteristics of periodic signals that are exploited to develop a variety of application circuits in IC design. Controlling the duty cycle and frequency provides a method to develop adaptable circuits for a variety of applications. These applications range from stable on-chip clock generation circuits, on-chip voltage regulation circuits, and Physical unclonable functions for hardware security applications. Ring oscillator circuits that are developed with CMOS inverter circuits provide a simple, versatile flexible method to generated periodic signals on an IC chip. A digitally controlled ring oscillator circuit can be adapted to control its duty cycle ...


Slow Relaxation Dynamics In Binary Glasses During Stress-Controlled, Tension-Compression Cyclic Loading, Nikolai V. Priezjev Oct 2018

Slow Relaxation Dynamics In Binary Glasses During Stress-Controlled, Tension-Compression Cyclic Loading, Nikolai V. Priezjev

Mechanical and Materials Engineering Faculty Publications

The effect of cyclic loading on relaxation dynamics and mechanical properties of metallic glasses is studied using molecular dynamics simulations. We consider the Kob-Andersen three-dimensional binary mixture rapidly cooled across the glass transition and subjected to thousands of tension-compression cycles in the elastic range. It was found that during cyclic loading at constant pressure, the system is relocated to progressively lower levels of the potential energy, thus promoting greater densification and higher strength. Furthermore, with increasing stress amplitude, the average glass density increases and the minimum of the potential energy becomes deeper, while the elastic modulus is reduced. The typical ...


Evaluation Of Tseb Turbulent Fluxes Using Different Methods For The Retrieval Of Soil And Canopy Component Temperatures From Uav Thermal And Multispectral Imagery, Héctor Nieto, William P. Kustas, Alfonso F. Torres-Rúa, Joseph G. Alfieri, Feng Gao, Martha C. Anderson, W. Alex White, Lisheng Song, María Del Mar Alsina, John H. Prueger, Mac Mckee, Manal Elarab, Lynn G. Mckee Sep 2018

Evaluation Of Tseb Turbulent Fluxes Using Different Methods For The Retrieval Of Soil And Canopy Component Temperatures From Uav Thermal And Multispectral Imagery, Héctor Nieto, William P. Kustas, Alfonso F. Torres-Rúa, Joseph G. Alfieri, Feng Gao, Martha C. Anderson, W. Alex White, Lisheng Song, María Del Mar Alsina, John H. Prueger, Mac Mckee, Manal Elarab, Lynn G. Mckee

AggieAir Publications

The thermal-based Two-Source Energy Balance (TSEB) model partitions the evapotranspiration (ET) and energy fluxes from vegetation and soil components providing the capability for estimating soil evaporation (E) and canopy transpiration (T). However, it is crucial for ET partitioning to retrieve reliable estimates of canopy and soil temperatures and net radiation, as the latter determines the available energy for water and heat exchange from soil and canopy sources. These two factors become especially relevant in row crops with wide spacing and strongly clumped vegetation such as vineyards and orchards. To better understand these effects, very high spatial resolution remote-sensing data from ...


Rheological Properties Of Warm Mix Asphalt Binders And Warm Mix Asphalt Binders Containing Polyphosphoric Acid, Jun Liu, Kezhen Yan, Jenny Liu Sep 2018

Rheological Properties Of Warm Mix Asphalt Binders And Warm Mix Asphalt Binders Containing Polyphosphoric Acid, Jun Liu, Kezhen Yan, Jenny Liu

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This paper presents the laboratory investigation of properties of warm mix asphalt (WMA) binders and WMA binders containing polyphosphoric acid (PPA).Two types of warm mix additives were used to produce the WMA binders. Superpave tests were carried out on original and short-term aged binders through the rotational viscometer, the dynamic shear rheometer (DSR), and the bending beam rheometer (BBR). The results indicated that the WMA binders with different warm mix additives showed different viscosity values, however, the addition of PPA remarkably increased the viscosity values of these two kinds of WMA binders used, in the present study, to a ...


Temperature Effects On Helium Filled Soap Bubble Particle Tracking Velocimetry., Michael C. Blum Aug 2018

Temperature Effects On Helium Filled Soap Bubble Particle Tracking Velocimetry., Michael C. Blum

Electronic Theses and Dissertations

Helium Filled Soap Bubble (HFSB) Particle Tracking Velocimetry (PTV) methods are becoming increasingly popular as they provide a low cost, safe option for reliable flow visualization. Several studies have been conducted to understand the accuracy of such systems under normal temperatures and pressures; however, no such studies to date have examined accuracy of HFSB PTV at high temperatures. The goal of this study is to characterize the capability of HFSB PTV methods to visualize air flow through a rectangular duct at elevated temperature. A heated wind tunnel was designed to heat up to 150 m3/h of 25 °C ...


The Yielding Transition In Periodically Sheared Binary Glasses At Finite Temperature, Nikolai V. Priezjev Jul 2018

The Yielding Transition In Periodically Sheared Binary Glasses At Finite Temperature, Nikolai V. Priezjev

Mechanical and Materials Engineering Faculty Publications

Non-equilibrium molecular dynamics simulations are performed to investigate the dynamic behavior of three-dimensional binary glasses prepared via an instantaneous quench across the glass transition. We found that with increasing strain amplitude up to a critical value, the potential energy approaches lower minima in steady state, whereas the amplitude of shear stress oscillations becomes larger. Below the yielding transition, the storage modulus dominates the mechanical response, and the gradual decay of the potential energy over consecutive cycles is accompanied by reduction in size of transient clusters of atoms with large nonaffine displacements. In contrast, above the yield strain, the loss modulus ...