Engineering Commons^™

Effects Of Fiber Clustering On Fatigue Behavior Of Steel Fiber Reinforced Concrete Beams, Danying Gao, Zhiqiang Gu, Congjie Wei, Chenglin Wu, Yuyang Pang

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This paper investigated the effects of fiber clustering on fatigue behavior of steel-fiber-reinforced concrete (SFRC) beams with reinforcements by experimental and numerical analysis. The steel fiber volume fractions of beams were 0 vol%, 0.5 vol%, 1.0 vol%, and 1.5 vol%. One beam was tested under static loading, and eight beams under fatigue loading with different stress levels. Moreover, the fiber distribution in the cross section of concrete was experimentally characterized to understand the underlying mechanism. The results indicated that the fatigue life of beam increased with increasing fiber volume fraction from 0 to 1.0 vol% and decreased from 1.0 vol% …

Improved Predictive Modeling Techniques For Non-Linear Solder Material Behavior, Arman Millian Ahari

Dissertations and Theses

Accurate prediction of fatigue life of solder joints in electronic packaging applications becomes of critical importance as semiconductor device technology and manufacturing constraints grow in complexity. To gain visibility on IC device performance and reliability, thermo-mechanical simulation is performed based on a unified, viscoplastic material model, which is dependent on nine parameters.

In this study, an improved method of Anand parameter extraction, which involves curve-fitting non-linear experimental stress data, is proposed to improve the accuracy of numerical predictions for solder reliability. Theoretical equations for uni-axial stress-strain response and creep response are derived, then details on their relevance to experimental and …

Undrained Cyclic Loading Of Low Plasticity Silty Soils In The Pacific Northwest Using Laboratory And Field Cyclic Shear Testing, Angelica Melissa Preciado Reyes

Dissertations and Theses

The cyclic behavior of a fine-grained low plasticity silty soil (plasticity index of approximately 15) at a site in Portland, Oregon, is characterized using a field and laboratory cyclic shear test program. The field cyclic tests were performed using the NHERI@UTexas large mobile shakers T-Rex and Rattler. The laboratory tests were performed using resonant column torsional shear and cyclic direct simple shear devices. This testing program's results were used to evaluate the soil's potential to develop excess pore water pressure with cyclic shear strains ranging from 0.00001% to 3%. The laboratory cyclic test results are compared against field cyclic test …

The Return To Anisotropy Across A Jet In Crossflow, Gregory P. Sakradse

Dissertations and Theses

With data from experiments on a jet of air emitting from an orifice flush with the floor of a wind tunnel providing a transverse flow, analysis is conducted to extract information about the state of anisotropy in the Reynolds stress tensor. Inflow velocities are modulated across two distinct turbulence intensity regimes while holding jet exit conditions constant, providing an opportunity to isolate effects of both jet to crossflow velocity ratio, r and the effects of the turbulence carried by the crossflow. Anisotropy in the Reynolds stress tensor is examined through anisotropy invariant maps and evolution of the function F, …

Development Of A New Electro-Osmotic Consolidation Apparatus, Yenni Mariana Ramírez-Mazo, Juan Pablo Osorio, Sergio Agudelo

Conference papers

Electro-osmotic consolidation is a ground improvement technique in which a DC voltage is applied to the soil via electrodes, in order to drain the water contained in the pores increasing the effective stress, and thus improving the geotechnical properties of the soil. The technique increases the shear strength, reduces the compressibility, and changes the chemical composition of the saturated soft clayey and silty soils to which it can be applied. Electro-osmotic consolidation has been successfully applied in different projects worldwide. This paper presents the development of a new electro-osmotic consolidation apparatus built at Universidad de Antioquia. Tests were carried on …

Geological Origin As An Input Variable In Reliability-Based Designs: For An Accurate Exploration In Geotechnical Engineering, Juan Camilo Viviescas, Juan Pablo Osorio

Conference papers

Soil is one of the most difficult materials to characterize realistically, which partly explains the uncertainty between the designs and the geostructures real behavior. Different recommendations have arisen with respect to carrying out field investigations in order to reduce the uncertainties inherent to the soil. However, the field exploration and the implementation of sophisticated geotechnical models have proven to be insufficient to mitigate the geotechnical uncertainty. Therefore, Reliability-Based Designs (RBD) emerge as a decision-making tool through the definition of the probability of failure in conjunction with the typical Factors of Safety. RBD requires a previous understanding of the most appropriate …

Biodegradable Nanocomposite Multifunctional Packaging Film For Fruits, Kalpani Y. Perera, Shubham Sharma, Dileswar Pradhan, Amit Jaiswal, Swarna Jaiswal

Articles

Biopolymers have been used in food packaging in recent years due to high pollution rates and decreased biodegradation of synthetic polymers. Chitosan (CH) and Sodium alginate (SA) are both biodegradable biopolymers with excellent film forming capability. TiO2 nanoparticles have high mechanical strength, degradation ability and antimicrobial properties, which are beneficial in food packaging. The aim of the current work is to develop the biodegradable multifunctional nanocomposite film for fruit (i.e., Pear) packaging applications. Bionanocomposite film was prepared by solvent casting method using CH-SA and various concentrations of TiO2. The multifunctional properties such as UV barrier, thermal, water retention, mechanical, chemical, …

Automatic Identification And Monitoring Of Plant Diseases Using Unmanned Aerial Vehicles: A Review, Krishna Neupane, Fulya Baysal-Gurel

Agricultural and Environmental Sciences Faculty Research

Disease diagnosis is one of the major tasks for increasing food production in agriculture. Although precision agriculture (PA) takes less time and provides a more precise application of agricultural activities, the detection of disease using an Unmanned Aerial System (UAS) is a challenging task. Several Unmanned Aerial Vehicles (UAVs) and sensors have been used for this purpose. The UAVs’ platforms and their peripherals have their own limitations in accurately diagnosing plant diseases. Several types of image processing software are available for vignetting and orthorectification. The training and validation of datasets are important characteristics of data analysis. Currently, different algorithms and …

Thermal Comfort Of Educational Spaces In Campus Buildings And Its Effect On The Functional Performance Case Study: University Of Garmian In The Kurdistan Region Of Iraq., Chrakhan Hama, Sherief Sheta, Mina Michel Samaan

Mansoura Engineering Journal

The Most important questions about the thermal comfort of educational spaces in campuses and its effect on the functional performance are simple ones. Why this subject important, Developing design standards for university buildings in the region to reach spaces that provide thermal comfort and high functionality, do educational spaces is lack thermal comfort requirements, and what is the effect of thermal comfort on the functionality of university educational buildings? Only by answering these questions can we develop design parameters to achieve the requirements of thermal comfort for education space users. The research about thermal comfort of educational spaces in campuses …

Stem For All Showcase Report, Bruce G. Bukiet, James M. Lipuma

STEM Month

This article and the associated STEM for all showcase submission video (https://www.youtube.com/watch?v=Clps427rdDc) was presented at the NSF 2021 STEM FOR ALL COVID, Equity & Social Justice Conference, May 11-18.

This article provides a description of the development of the STEM in your Home project in the STEM for Success initiative.

Unconventional Van Der Waals Heterostructures Beyond Stacking, Peter Sutter, Eli A. Sutter

Department of Electrical and Computer Engineering: Faculty Publications

Two-dimensional crystals provide exceptional opportunities for integrating dissimilar materials and forming interfaces where distinct properties and phenomena emerge. To date, research has focused on two basic heterostructure types: vertical van der Waals stacks and laterally joined monolayer crystals with in-plane line interfaces. Much more diverse architectures and interface configurations can be realized in the few-layer and multilayer regime, and if mechanical stacking and single-layer growth are replaced by processes taking advantage of self-organization, conversions between polymorphs, phase separation, strain effects, and shaping into the third dimension. Here, we highlight such opportunities for engineering heterostructures, focusing on group IV chalcogenides, a …

3d Printed Concrete & Polymer Concrete For Infrastructure Applications, Daniel Heras Murcia

Civil Engineering ETDs

Additive manufacturing technology has been established as one of the fastest-growing building technologies worldwide. Three-dimensional concrete printing (3DCP) has developed an increasing interest in the last decade due to its prospects as a transformative technology for industries such as the concrete precast. Besides the improvements in automation technologies in construction, traditional construction has faced considerable challenges: high accident rates, labor dependency, significant potential for automation, and high costs associated with the use of traditional formwork. In this context, three-dimensional concrete, also referred to as physical prototyping, is a novel construction technique in which the concrete is extruded layer-to-layer. 3DCP is …

Computer-Aided Diagnosis Of Low Grade Endometrial Stromal Sarcoma (Lgess), Xinxin Yang, Mark Stamp

Faculty Research, Scholarly, and Creative Activity

Low grade endometrial stromal sarcoma (LGESS) accounts for about 0.2% of all uterine cancer cases. Approximately 75% of LGESS patients are initially misdiagnosed with leiomyoma, which is a type of benign tumor, also known as fibroids. In this research, uterine tissue biopsy images of potential LGESS patients are preprocessed using segmentation and stain normalization algorithms. We then apply a variety of classic machine learning and advanced deep learning models to classify tissue images as either benign or cancerous. For the classic techniques considered, the highest classification accuracy we attain is about 0.85, while our best deep learning model achieves an …

Human-Machine Communication: Complete Volume. Volume 3. Diffusion Of Human-Machine Communication During And After The Covid-19 Pandemic

Human-Machine Communication

This is the complete volume of HMC Volume 3. Diffusion of Human-Machine Communication During and After the COVID-19 Pandemic

What Will Affect The Diffusion Of Ai Agents?, James W. Dearing

Human-Machine Communication

For billions of people, the threat of the Novel Coronavirus SARS-CoV-2 and its variants has precipitated the adoption of new behaviors. Pandemics are radical events that disrupt the gradual course of societal change, offering the possibility that some rapidly adopted innovations will persist in use past the time period of the event and, thus, diffuse more rapidly than in the absence of such an event. Human-machine communication includes a range of technologies with which many of us have quickly become more familiar due to stay-athome orders, distancing, workplace closures, remote instruction, home-bound entertainment, fear of contracting COVID-19, and boredom. In …

The Role Of Vidura Chatbot In The Diffusion Of Knowcovid-19 Gateway, Kerk F. Kee, Prasad P. Calyam, Hariharan Regunath

Human-Machine Communication

The COVID-19 pandemic is an unprecedented global emergency. Clinicians and medical researchers are suddenly thrown into a situation where they need to keep up with the latest and best evidence for decision-making at work in order to save lives and develop solutions for COVID-19 treatments and preventions. However, a challenge is the overwhelming numbers of online publications with a wide range of quality. We explain a science gateway platform designed to help users to filter the overwhelming amount of literature efficiently (with speed) and effectively (with quality), to find answers to their scientific questions. It is equipped with a chatbot …

Communicative Development And Diffusion Of Humanoid Ai Robots For The Post-Pandemic Health Care System, Do Kyun David Kim, Gary Kreps, Rukhsana Ahmed

Human-Machine Communication

As humanoid robot technology, anthropomorphized by artificial intelligence (AI), has rapidly advanced to introduce more human-resembling automated robots that can communicate, interact, and work like humans, we have begun to expect active interactions with Humanoid AI Robots (HAIRs) in the near future. Coupled with the HAIR technology development, the COVID-19 pandemic triggered our interest in using health care robots with many substantial advantages that overcome critical human vulnerabilities against the strong infectious COVID-19 virus. Recognizing the tremendous potential for the active application of HAIRs, this article explores feasible ways to implement HAIRs in health care and patient services and suggests …

Our Future Arrived: Diffusion Of Human-Machine Communication And Transformation Of The World For The Post-Pandemic Era, Do Kyun David Kim, Gary Kreps, Rukhsana Ahmed

Human-Machine Communication

The world is getting into a new phase in history. For the first time, humans are verbally communicating and developing meaningful relationships with non-living objects. AI is a wormhole to open a gateway to the new world, and the COVID-19 pandemic prepared the world to transform its system to be an open system that responds to, communicates with, and utilizes the remnants coming out of the wormhole of the new world. Now, we urgently need to create a holistic discourse on how we can recognize, develop, or shape the identities of communicable machines as people develop a partnership with them. …

Perspectives On Computing Ethics: A Multi-Stakeholder Analysis, Damian Gordon, Ioannis Stavrakakis, Paul J. Gibson, Brendan Tierney, Anna Becevel, Andrea Curley, Michael Collins, William O'Mahony, Dympna O'Sullivan

Articles

Purpose:

Computing ethics represents a long established, yet rapidly evolving, discipline that grows in complexity and scope on a near-daily basis. Therefore, to help understand some of that scope it is essential to incorporate a range of perspectives, from a range of stakeholders, on current and emerging ethical challenges associated with computer technology. This study aims to achieve this by using, a three-pronged, stakeholder analysis of Computer Science academics, ICT industry professionals, and citizen groups was undertaken to explore what they consider to be crucial computing ethics concerns. The overlap between these stakeholder groups are explored, as well as whether …

Co-Carriage Of Metal And Antibiotic Resistance Genes In Sewage Associated Staphylococci, Atena Amirsoleimani, Gail M. Brion, Patrice Francois

Civil Engineering Faculty Publications

Controlling spread of resistance genes from wastewater to aquatic systems requires more knowledge on how resistance genes are acquired and transmitted. Whole genomic sequences from sewage-associated staphylococcus isolates (20 S. aureus, 2 Staphylococcus warneri, and 2 Staphylococcus delphini) were analyzed for the presence of antibiotic resistance genes (ARGs) and metal resistance genes (MRGs). Plasmid sequences were identified in each isolate to investigate co-carriage of ARGs and MRGs within. BLASTN analysis showed that 67% of the isolates carried more than one ARG. The carriage of multiple plasmids was observed more in CC5 than CC8 S. aureus strains. Plasmid …

Energy Dissipation Using Negative Stiffness Shells, Mohamed Elgawady, Yasser Darwish

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

A negative stiffness shell has a convex first position, but can transition or snap to a concave second position under a force applied to the exterior surface of the shell in the convex first position. During the transition, the shell exhibits negative stiffness that permits a large amount of energy to be absorbed. The negative stiffness shell can withstand a high initial force threshold prior to transitioning. In the second, concave position the shell can still resist force. Moreover, it is possible for the shell to revert back to the first, convex position with minimal plastic deformation for subsequent use. …

Impact Of Clay Stabilizer On The Methane Desorption Kinetics And Isotherms Of Longmaxi Shale, China, Zhong Hua Liu, Jia Chun Wang, Baojun Bai, Yan Ling Wang

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Knowing methane desorption characteristics is essential to define the contribution of adsorbed gas to gas well production. To evaluate the synthetic effect of a clay stabilizer solution on methane desorption kinetics and isotherms pertaining to Longmaxi shale, an experimental setup was designed based on the volumetric method. The objective was to conduct experiments on methane adsorption and desorption kinetics and isotherms before and after clay stabilizer treatments. The experimental data were a good fit for both the intraparticle diffusion model and the Freundlich isotherm model. We analyzed the effect of the clay stabilizer on desorption kinetics and isotherms. Results show …

On-Site/In Situ Continuous Detecting Ppb-Level Metal Ions In Drinking Water Using Block Loop-Gap Resonators And Machine Learning, Sangmin Oh, Imtiaz Hossen, Juan R. Luglio, Gusphyl Justin, James Richie, Henry Medeiros, Chung-Hoon Lee

Electrical and Computer Engineering Faculty Research and Publications

Microwave measurements and machine learning algorithms are presented to estimate metal ion concentrations in drinking water. A novel block loop gap resonator (BLGR) as a microwave probe is designed and fabricated to estimate Pb ion concentrations in city water as low as 1 ppb with an rms error of 0.18 ppb. No physical contact between the BLGR probe and the water sample allows on-site/in situ continuous detection of ppb-level metal ion concentrations. The S₁₁ raw data (amplitude and phase) from the BLGR are used to classify and estimate metal ion concentrations using a support vector regression algorithm. The performance …

Start With Simple Spacecraft: Cansat & Cricketsat, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Bob Twiggs titled "Start with Simple Spacecraft: CanSat & CricketSat" from September 22, 2021.

Simulation For A Mems-Based Ctrnn Ultra-Low Power Implementation Of Human Activity Recognition, Muhammad Emad-Ud-Din, Mohammad H. Hasan, Roozbeh Jafari, Siavash Pourkamali, Fadi M. Alsaleem

Durham School of Architectural Engineering and Construction: Faculty Publications

This paper presents an energy-efficient classification framework that performs human activity recognition (HAR). Typically, HAR classification tasks require a computational platform that includes a processor and memory along with sensors and their interfaces, all of which consume significant power. The presented framework employs microelectromechanical systems (MEMS) based Continuous Time Recurrent Neural Network (CTRNN) to performHAR tasks very efficiently. In a real physical implementation, we show that the MEMS-CTRNN nodes can perform computing while consuming power on a nano-watts scale compared to the micro-watts state-of-the-art hardware. We also confirm that this huge power reduction doesn’t come at the expense of reduced …

Emr: A New Metric To Assess The Resilience Of Directional Mmwave Channels To Blockages, Faith Erden, Ozgur Ozdemir, Ismail Guvenc, David W. Matolak

Faculty Publications

Millimeter-wave (mmWave) communication systems require narrow beams to compensate for high path loss and to increase the communication range. If an obstacle blocks the dominant communication direction, alternative paths (directions) should be quickly identified to maintain reliable connectivity. In this paper, we introduce a new metric to quantify the Effective Multipath Richness (EMR) of a directional communication channel in the angular domain. In particular, the proposed metric takes into account the strength and spatial diversity of the resolved Multipath Components (MPCs), while also considering the beamwidth of the communication link and the blockage characteristics. The metric is defined as a …

Characterization Of Tea (Camellia Sinensis) Granules For Quality Grading Using Computer Vision System, Md Towfiqur Rahman, Sabiha Ferdous, Mariya Sultana Jenin, Tanjina Rahman Mim, Masud Alam, Muhammad Rashed Al Mamun

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Tea (Camellia sinensis) has been found as an important medicinal beverage for human which is consumed all over the world. Primarily, the majority of tea is being cultivated in Asia and Africa, however it is commercially produced by more than 60 countries. Though substantial amount is produced, its processing system is still underdeveloped which leads to decrease in export opportunity as well as low monetary value. Moreover, the traditional method of tea grading and sorting is laborious, inefficient, and costly which ultimately produces the low-quality heterogeneous products. Processing and grading of tea granules after drying is very important …

Assessment Of A Program For Sars-Cov-2 Screening And Environmental Monitoring In An Urban Public School District, John Crowe, Andy T. Schnaubelt, Scott Schmdit Bonne, Kathleen Angell, Julia Bai, Teresa Eske, Molly Nicklin, Catherine Pratt, Bailey White, Brodie Crotts-Hannibal, Nicholas Staffend, Vicki Herrera, Jeramie Cobb, Jennifer Connor, Julie Carstens, Jonell Tempero, Lori Bouda, Matthew Ray, James V. Lawler, W Scott Campbell, John-Martin Lowe, Joshua Santarpia, Shannon Bartelt-Hunt, Michael Wiley, David Brett-Major, Cheryl Logan, Jana Broadhurst

Department of Civil and Environmental Engineering: Faculty Publications

IMPORTANCE Scalable programs for school-based SARS-CoV-2 testing and surveillance are needed to guide in-person learning practices and inform risk assessments in kindergarten through 12th grade settings. OBJECTIVES To characterize SARS-CoV-2 infections in staff and students in an urban public school setting and evaluate test-based strategies to support ongoing risk assessment and mitigation for kindergarten through 12th grade in-person learning. DESIGN, SETTING, AND PARTICIPANTS This pilot quality improvement program engaged 3 schools in Omaha, Nebraska, for weekly saliva polymerase chain reaction testing of staff and students participating in in-person learning over a 5-week period from November 9 to December 11, 2020. …

Optimal Placement Of Fuses And Switches In Active Distribution Networks Using Value-Based Minlp, N. Gholizadeh, S.H. Hosseinian, M. Abedi, Hamed Nafisi, P. Siano

Articles

Contingency conditions in distribution networks create financial losses for different parts of the system including electricity customers, electricity retailers, distributed generation (DG) units, etc. Therefore, protective device allocation methods have been introduced in recent years to enhance the reliability of the power system. In this study, a new formulation is proposed to find the optimal places of sectionalizing switches and fuses while taking the financial loss of both electricity customers and DG units into account. The current method has the flexibility to consider DG effect on any location of the network and its islanded operation in case of contingencies. Moreover, …

Flexible Mold For Microstructures Replication, Zefu Ren, Dae Won Kim

Student Works

Space debris has been a growing concern in space exploration sector. To combat this issue, biomimicry is utilized to create a gecko’s feet microstructure that will be attached to a gripper or robotic arm. This will enable capture of debris through the use of dry adhesive microstructure. However, the production of such microstructures is expensive which hinders their implementation. The objective of this research is to develop an advanced fabrication process to mass produce gecko’s feet microstructure with soft polymer mold. The possibility of using different coating methods with coating materials will be justified. The process of fabricating mold and …