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Articles 83251 - 83280 of 196768

Full-Text Articles in Engineering

Effect Of Arm Motion On Standing Lateral Jump Performance, Arif Ahmed Sohel Dec 2017

Effect Of Arm Motion On Standing Lateral Jump Performance, Arif Ahmed Sohel

Masters Theses

Previous jumping studies have examined the role of arm swing in vertical and horizontal long jump performance, but none have been found which studied the role of arm swing in standing lateral jumps. The purpose of this study was to investigate the effect of arm motion on standing lateral jump performance and to examine the biomechanical mechanisms that may explain differences in jump distance.

A series of lateral jump experiments was performed for two jump cases (free and restricted arms) in which six participants jumped laterally for maximum distance from two in-ground force platforms. A motion capture system collected 3D …


Query Expansion Techniques For Enterprise Search, Eric M. Domke Dec 2017

Query Expansion Techniques For Enterprise Search, Eric M. Domke

Masters Theses

Although web search remains an active research area, interest in enterprise search has waned. This is despite the fact that the market for enterprise search applications is expected to triple within the next six years, and that knowledge workers spend an average of 1.6 to 2.5 hours each day searching for information. To improve search relevancy, and hence reduce this time, an enterprise- focused application must be able to handle the unique queries and constraints of the enterprise environment. The goal of this thesis research was to develop, implement, and study query expansion techniques that are most effective at improving …


A Cfd Study Of A Multi-Element Front Wing For A Formula One Racing Car, Shardul C. Kachare Dec 2017

A Cfd Study Of A Multi-Element Front Wing For A Formula One Racing Car, Shardul C. Kachare

Masters Theses

Presently, one of the key factors in determining a success of an open wheel racecar such as Formula One or Indy car, is its aerodynamic efficiency. A modern racecar front wing can generate about 30% of the total downforce. The present study focuses on investigating the aerodynamic characteristics of such highly efficient multi-element front wing for a Formula One racecar by conducting a three-dimensional computational analysis using Reynolds Averaged Navier-Strokes model. A three-dimensional computational study is performed investigating predictive capability of the structured trimmer and unstructured polyhedral meshing model to generate a three-dimensional volume mesh for a multi-element front wing. …


Investigation On Ti6al4v-V-Cr-Fe-Ss316 Multi-Layers Metallic Structure Fabricated By Laser 3d Printing, Wei Li, Frank W. Liou, Joseph William Newkirk, Karen M. Brown Taminger, William J. Seufzer Dec 2017

Investigation On Ti6al4v-V-Cr-Fe-Ss316 Multi-Layers Metallic Structure Fabricated By Laser 3d Printing, Wei Li, Frank W. Liou, Joseph William Newkirk, Karen M. Brown Taminger, William J. Seufzer

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Joining titanium alloy and stainless steel is becoming an urgent need since their outstanding mechanical properties can be utilized integratedly. However, direct fusion joining of Ti6Al4V to SS316 can cause brittle Ti-Fe intermetallics which compromise join bonds’ mechanical properties. In this research, Laser 3D Printing was applied to explore a new Ti6Al4V to SS316 multi-metallic structure. A novel filler transition route was introduced (Ti6Al4V → V → Cr → Fe → SS316) to avoid the Ti-Fe intermetallics. Two experimental cases were performed for comparison to evaluate this novel route’s effect. In the first case, SS316 layer was directly deposited on …


Anodic Catalysts For Anion Exchange Membrane Fuel Cells, Aaron Joseph Roy Dec 2017

Anodic Catalysts For Anion Exchange Membrane Fuel Cells, Aaron Joseph Roy

Chemical and Biological Engineering ETDs

With a limited availability of energy resources from petroleum and other fossil fuels, as well as growing concerns relating to the environmental implications of fossil fuel emissions, non-carbon fuels which can be utilized in proton and anion exchange membrane fuel cells (PEMFC’s/AEMFC’s), such as hydrogen and hydrazine hydrate (HH), are becoming more attractive as alternative fuels. Historically, platinum and platinum group metal catalysts (PGM) have been used as cathode and anode catalyst materials for both PEMFC’s and AEMFC’s. Although these catalysts are the highest performing catalysts available for the conversion of hydrogen energy in fuel cells, the limited availability and …


Fifth Graders’ Creativity In Inventions With And Without Creative Articulation Instruction, Darcie K. Kress, Audrey C. Rule Nov 2017

Fifth Graders’ Creativity In Inventions With And Without Creative Articulation Instruction, Darcie K. Kress, Audrey C. Rule

Journal of STEM Arts, Crafts, and Constructions

Industry and authors of 21st Century Skill Frameworks are calling for student proficiency in creativity, problem-solving, innovation, collaboration, and communication skills. This project involved 13 fifth grade gifted students in inventing products for a specified audience with a set of given materials, time limit, and topic constraints. The complex, challenging project supports Next Generation Science Engineering Process Standard 3-5-ETS1-2 and applies concepts of plant and animal adaptations. The study had a counterbalanced, repeated measures design in which student made an initial invention during the pretest, then participated in two trials with one in the control condition and the other …


Challenging Elementary Learners With Programmable Robots During Free Play And Direct Instruction, Kimberly S. Mccoy-Parker, Lindsey N. Paull, Audrey C. Rule, Sarah E. Montgomery Nov 2017

Challenging Elementary Learners With Programmable Robots During Free Play And Direct Instruction, Kimberly S. Mccoy-Parker, Lindsey N. Paull, Audrey C. Rule, Sarah E. Montgomery

Journal of STEM Arts, Crafts, and Constructions

Computer programming skills are important to many current careers; teaching robot coding to elementary students can start a positive foundation for technological careers, develop problem-solving skills, and growth mindsets. This study, through a repeated measures design involving students in two classrooms at two widelyseparated grade levels (first graders aged 6-7 years and fifth graders aged 10-11 years), determined if allowing students to challenge themselves with coding exercises in the experimental condition resulted in greater learning and more positive attitudes than a more structured set of exercises provided by the teacher in the control condition. Background instruction in coding and using …


Reading Nonfiction Science Literature With And Without Arts Integration Activities, Elizabeth Mccartney, Catherine Mochal, Victoria Boyd, Audrey C. Rule, Sarah E. Montgomery Nov 2017

Reading Nonfiction Science Literature With And Without Arts Integration Activities, Elizabeth Mccartney, Catherine Mochal, Victoria Boyd, Audrey C. Rule, Sarah E. Montgomery

Journal of STEM Arts, Crafts, and Constructions

This study explores the integration of the arts into the teaching of science nonfiction texts during literacy instruction. Sixty-one elementary students (15 second graders, 25 third graders, and 21 fifth graders) attending schools of differing socio-economic levels participated in this study. The study examined the effects of artsintegration on student content knowledge, engagement level, and attitudes toward learning regarding science nonfiction texts. Throughout the eight-week study, students experienced both the traditional no-arts control condition and the experimental arts-integration condition in two-week segments for different science topics. Both conditions employed literacy strategies to teach comprehension of science nonfiction texts. The resulting …


Examining Natural Selection By Sketching And Making Models Of The Finches Of The Galapagos Islands, Phoebe J. Z. Pittman, Jolene K. Teske Nov 2017

Examining Natural Selection By Sketching And Making Models Of The Finches Of The Galapagos Islands, Phoebe J. Z. Pittman, Jolene K. Teske

Journal of STEM Arts, Crafts, and Constructions

This practical lesson describes how students in six eighth grade science classes participated in a lesson combining the National Core Arts Standards with the Next Generation Science Standards. The goal of the lesson was to provide visual representations of finch beak form and function so students could better understand genetic variation and how environmental pressures influence natural selection. Students sketched a finch with a large, medium, or small beak, corresponding to an experiment they had conducted with picking up different sizes of seeds with different sizes of binder clips. Using modeling with a variety of media, students created bird beaks …


Cinematherapy In Gifted Education Identity Development: Integrating The Arts Through Stem-Themed Movies, Timothy C. Kangas, Michelle Cook, Audrey C. Rule Nov 2017

Cinematherapy In Gifted Education Identity Development: Integrating The Arts Through Stem-Themed Movies, Timothy C. Kangas, Michelle Cook, Audrey C. Rule

Journal of STEM Arts, Crafts, and Constructions

Gifted students, because of their advanced development compared to peers, have emotional needs that require differentiated education programs. Asynchronous social and emotional development of gifted students often leads to identity issues. Cinematherapy can be used to help gifted students explore their identities through analysis of the actions of gifted characters in films. This practical article suggests STEM-themed movies with characters facing challenges useful for gifted student identity development. The Autonomous Learners Model is used to classify gifted learners in the movies to assist teachers in matching movies to the needs of gifted learners. Tables of STEM-themed movies with gifted characters …


How The Arts Standards Support Stem Concepts: A Journey From Stem To Steam, Ksenia S. Zhbanova Nov 2017

How The Arts Standards Support Stem Concepts: A Journey From Stem To Steam, Ksenia S. Zhbanova

Journal of STEM Arts, Crafts, and Constructions

This issue of the Journal of STEM Arts, Crafts, and Constructions is focused on the effects of integrating arts with STEM areas, an important and widely-considered topic in education today. This editorial provides an overview of the current state of the arts and STEM areas integration paradigm, an analysis of the benefits of the arts integration with the STEM subjects, and an overview of the history of the arts anchor standards. Comparison and connections between the National Arts Core anchor arts standards, the scientific method, engineering design process, and the 5E learning cycle are also illuminated. Summaries of the practical …


16-08 Does Location Matter? Performance Analysis Of The Affordable Housing Programs In Dallas-Fort Worth, Shima Hamidi, Somayeh Moazzeni, Jinat Jahan, Reza Sardari, David Weinreich Nov 2017

16-08 Does Location Matter? Performance Analysis Of The Affordable Housing Programs In Dallas-Fort Worth, Shima Hamidi, Somayeh Moazzeni, Jinat Jahan, Reza Sardari, David Weinreich

Transportation Research Center Reports

On June 2015, the Texas Department of Housing and Community Affairs lost a case in the U.S. Supreme Court due to their failure to provide equitable affordable housing under the Low Income Housing Tax Credit (LIHTC) program. The U.S. Supreme Court decision has shaken the affordable housing definition by highlighting the importance of location in housing affordability. To best assist low-income families, what should ‘high-opportunity areas’ concretely provide? First and foremost is transportation affordability.

Transportation is more than a sheer convenience for Americans. Looking solely at housing costs is a misleading measure of affordability and a disservice to low-income families. …


A High Accuracy Microwave Radiometric Thermometer To Measure Internal Body Temperature, Michael D. Grady Nov 2017

A High Accuracy Microwave Radiometric Thermometer To Measure Internal Body Temperature, Michael D. Grady

USF Tampa Graduate Theses and Dissertations

The Center for Disease Control and Prevention (CDC) released heat illness data which highlighted that ~29 heat stress hospitalizations and ~3 heat-related deaths occurred every day during the summer months within the US from years 2000 to 2014. Heatstroke- the most severe form of heat illness which oftentimes lead to death- has been cited to be entirely preventable if a timely intervention is introduced. This dissertation uses microwave radiometric thermometry to perform wireless non-invasive internal body temperature monitoring which can enable intervention methods that help to prevent deaths associated with heat-illness.

Overall, this dissertation develops a comprehensive closed-form analytical radiometric …


Graph-Based Latent Embedding, Annotation And Representation Learning In Neural Networks For Semi-Supervised And Unsupervised Settings, Ismail Ozsel Kilinc Nov 2017

Graph-Based Latent Embedding, Annotation And Representation Learning In Neural Networks For Semi-Supervised And Unsupervised Settings, Ismail Ozsel Kilinc

USF Tampa Graduate Theses and Dissertations

Machine learning has been immensely successful in supervised learning with outstanding examples in major industrial applications such as voice and image recognition. Following these developments, the most recent research has now begun to focus primarily on algorithms which can exploit very large sets of unlabeled examples to reduce the amount of manually labeled data required for existing models to perform well. In this dissertation, we propose graph-based latent embedding/annotation/representation learning techniques in neural networks tailored for semi-supervised and unsupervised learning problems. Specifically, we propose a novel regularization technique called Graph-based Activity Regularization (GAR) and a novel output layer modification called …


Multi-Target Extension For Beacon Foraging Methods, Christopher Sanford, Ziong Jiao, Jae Oh Nov 2017

Multi-Target Extension For Beacon Foraging Methods, Christopher Sanford, Ziong Jiao, Jae Oh

Electrical Engineering and Computer Science - All Scholarship

Robotic foraging is a complex problem that encompasses both the problem of exploring an area and retrieval of targets. To solve this, biologically inspired algorithms have been proposed that handle the scenario when only one target exists, but requires extension to multiple targets. In both scenarios there exists problems of robot allocation and congestion, and we analyze ways of optimizing both allocation and minimizing congestion for our algorithms. We demonstrate the results through parameterized metrics and compare the improvements in each scenario.

This is a technical report on artificial intelligence, 2017, written by Sanford, Jiao, and Oh.


Multi-Dimensional Drought Risk Assessment Based On Socio-Economic Vulnerabilities And Hydro-Climatological Factors, Ali Ahmadalipour Nov 2017

Multi-Dimensional Drought Risk Assessment Based On Socio-Economic Vulnerabilities And Hydro-Climatological Factors, Ali Ahmadalipour

Dissertations and Theses

Drought is among the costliest natural hazards developing slowly and affecting large areas, which imposes severe consequences on society and economy. Anthropogenic climate change is expected to exacerbate drought in various regions of the globe, making its associated socioeconomic impacts more severe. Such impacts are of higher concern in Africa, which is mainly characterized by arid climate and lacking infrastructure as well as social development. Furthermore, the continent is expected to experience vast population growth, which will make it more vulnerable to the adverse effects of drought. This study provides the first comprehensive multi-dimensional assessment of drought risk across the …


Extending Motion Detection To Track Stopped Objects In Visual Multi-Target Tracking, Jacob H. White, Karl T. Salva, Randal W. Beard Nov 2017

Extending Motion Detection To Track Stopped Objects In Visual Multi-Target Tracking, Jacob H. White, Karl T. Salva, Randal W. Beard

Student Works

Various solutions to visual multi-target tracking have been proposed, but many of them are not capable of running in real time from a moving camera on an unmanned aerial vehicle (UAV). We present a tracker that runs in real time and tracks multiple objects while accounting for camera motion on a UAV. Our algorithm is capable of processing over 10 frames per second on a 1280x720 video sequence.

We utilize Recursive-RANSAC, an efficient algorithm for tracking multiple objects in clutter. Our work combines motion detection with optical flow and feature matching to allow stationary objects to be tracked. We use …


High Consequence Scenarios For North Korean Atmospheric Nuclear Tests With Policy Recommendations For The U.S. Government, Thomas S. Popik, Jordan T. Kearns, George H. Baker Iii, Henry F. Cooper, William R. Harris Nov 2017

High Consequence Scenarios For North Korean Atmospheric Nuclear Tests With Policy Recommendations For The U.S. Government, Thomas S. Popik, Jordan T. Kearns, George H. Baker Iii, Henry F. Cooper, William R. Harris

School of Integrated Sciences - Faculty Scholarship

The government of North Korea has declared high-altitude EMP-capability to be a “strategic goal” and has also threatened an atmospheric test of a hydrogen bomb. Atmospheric nuclear tests have the potential to cripple satellites and the undersea cable networks critical to communication, and navigation necessary for trans-Pacific trade among the U.S., China, and other nations. When a nuclear warhead is detonated at high altitude, a series of electromagnetic pulses radiate downward within the line of sight of the blast. These pulses can disable equipment with miniature electronics and long conductors. Electric grid controls and transmission systems are especially vulnerable. Intense …


Blanking Clearance And Punch Velocity Effects On The Sheared Edge Characteristic In Micro-Blanking Of Commercially Pure Copper Sheet, Didin Zakariya Lubis, Ichsan Ristiawan Nov 2017

Blanking Clearance And Punch Velocity Effects On The Sheared Edge Characteristic In Micro-Blanking Of Commercially Pure Copper Sheet, Didin Zakariya Lubis, Ichsan Ristiawan

Journal of Mechanical Engineering Science and Technology (JMEST)

This study aims to identify the influences between clearance and punch velocity on the part edge quality of blanked parts. Experiments have been conducted using material copper, punch-die clearance and punch velocity variations. In order to determine the reachable punch-die clearance and punch velocity required for blanking. The quality of the part-edge characteristics shows that higher punch velocity and decreases clearance value can improve the part-edge quality, resulting in smaller burr height and rollover, and a larger shear zone. Furthermore, it could be observed that the part-edge quality improvement when blanking with high punch velocity is much more distinct for …


Formula Of Moulding Sand, Bentonite And Portland Cement To Improve The Quality Of Al-Si Cast Alloy, Andoko Andoko, Poppy Puspitasari, Avita Ayu Permanasari, Didin Zakaria Lubis Nov 2017

Formula Of Moulding Sand, Bentonite And Portland Cement To Improve The Quality Of Al-Si Cast Alloy, Andoko Andoko, Poppy Puspitasari, Avita Ayu Permanasari, Didin Zakaria Lubis

Journal of Mechanical Engineering Science and Technology (JMEST)

A binder is any material used to strengthen the bonding of moulding sand grains. The primary function of the binder is to hold the moulding sand and other materialstogether to produce high-quality casts. In this study, there were four binder compositions being tested, i.e. 5% bentonite + 5% Portland cement, 4% bentonite + 6% Portland cement, 6% bentonite + 4% Portland cement, and 7% bentonite + 3% Portland cement. Each specimen was measured for its compressive strength, shear strength, tensile strength and permeability. The highest compressive strength was obtained fromthe specimen composed of 6% bentonite+ 4% Portland cement. The highest …


Modeling Of Antenna For Deep Target Hydrocarbon Exploration, Nadeem Nasir, Noorhana Yahya, Hasnah Mohd Zaid, Afza Shafie, Norhisham Hamid Nov 2017

Modeling Of Antenna For Deep Target Hydrocarbon Exploration, Nadeem Nasir, Noorhana Yahya, Hasnah Mohd Zaid, Afza Shafie, Norhisham Hamid

Journal of Mechanical Engineering Science and Technology (JMEST)

Nowadays control source electromagnetic method is used for offshore hydrocarbon exploration. Hydrocarbon detection in sea bed logging (SBL) is a very challenging task for deep target hydrocarbon reservoir. Response of electromagnetic (EM) field from marine environment is very low and it is very difficult to predict deep target reservoir below 2km from the sea floor. This work premise deals with modeling of new antenna for deep water deep target hydrocarbon exploration. Conventional and new EM antennas at 0.125Hz frequency are used in modeling for the detection of deep target hydrocarbon reservoir. The proposed area of the seabed model (40km ´ …


Properties Of Brass Under Different Pouring Temperatures In Sand Casting Process, Poppy Puspitasari, Avita Ayu Permanasari, Andoko Andoko, Bayu Angga Pratama Nov 2017

Properties Of Brass Under Different Pouring Temperatures In Sand Casting Process, Poppy Puspitasari, Avita Ayu Permanasari, Andoko Andoko, Bayu Angga Pratama

Journal of Mechanical Engineering Science and Technology (JMEST)

This study aimed to determine the toughness of casts produced by the sand casting process at various temperatures against brass, and to investigate the structure contained in the cast madeusing abrass metal mould. This study was experimental research that observed the results of a treatment applied to a specimen group. This pre-experimental study usedthe one-shot case study model in which a group of samples was given treatment. The results showed that the specimen poured at 900°C exhibiteda microstructure consisting ofgood Cu-Zn content, while that at 700°Chad the least Cu content. It indicates that the higher the temperature used for metal …


Development Of A Ferrite-Based Electromagnetic Wave Detector, Muhammad Hanis Bin Zakariah, Poppy Puspitasari, Nur Azliza Ahmad Nov 2017

Development Of A Ferrite-Based Electromagnetic Wave Detector, Muhammad Hanis Bin Zakariah, Poppy Puspitasari, Nur Azliza Ahmad

Journal of Mechanical Engineering Science and Technology (JMEST)

Direct detection of hydrocarbon by an active source using electromagnetic (EM) wave termed Sea Bed Logging (SBL) has shown very promising results. However, currently available electromagnetic wave technology has a number of challenges including sensitivity and lapsed time. Our initial response to this issue is to develop a ferrite-based EM wave detector for Sea Bed Logging (SBL). Ferrite bar and copper rings in various diameters were used as detector 1 (D1). For Detector 2 (D2), toroid added with copper wires in different lengths at the centre of it were used. The first experiment is to determine the inductance and resistance …


Thermogravimetric And Kinetic Analysis Of Cassava Starch Based Bioplastic, Nanang Eko Wahyuningtiyas, Heru Suryanto, Eddy Rudiyanto, Sukarni Sukarni, Poppy Puspitasari Nov 2017

Thermogravimetric And Kinetic Analysis Of Cassava Starch Based Bioplastic, Nanang Eko Wahyuningtiyas, Heru Suryanto, Eddy Rudiyanto, Sukarni Sukarni, Poppy Puspitasari

Journal of Mechanical Engineering Science and Technology (JMEST)

Cassava starch based bioplasticfor packaging application has great potency because of the various starchproducing plants in Indonesia.Bioplasticcan contribute to reduce the dependence on fossil fuels andpetroleumthat can solve the environmentalproblem.Thepurpose of this research is to find out the thermal decomposition and the activation energy of cassava starch based bioplastic. The methods weresynthesis bioplastic with cassava starch as main component and glycerol as plasticizer. The thermogravimetry analysis was conducted to obtain the decomposition process mechanism of bioplastic and the heating valueof bioplasticwas measured using theadiabatic bomb calorimetric. Data analysis was conducted using a fitting model approach with an acikalin method to …


Compositional And Structural Evolution During Ball Milling Of Ti-Based Metallic Glass Powder, Yanuar Rohmat Aji Pradana Nov 2017

Compositional And Structural Evolution During Ball Milling Of Ti-Based Metallic Glass Powder, Yanuar Rohmat Aji Pradana

Journal of Mechanical Engineering Science and Technology (JMEST)

Ti42Zr40Ta3Si7.5Sn7.5metallic glass powder prepared for subsequent consolidation by hot pressing were produced by high energy ball milling from amorphous ribbon and both of the compositional and structural evolution on milled powders were studied using XRD and DSC analyses. By using WC vial and balls, the abrasion of milling media occurred causing WC contamination on < 105 µm milled powder after 2 cycles of milling. Based on DSC analysis, the contamination clearly reduced theΔTxof the alloy up to 48%. On the other hand, the contamination were overcome after milling using SS vial and balls, proved by no crystal peak observed on XRD pattern of all milling cycle levels. However, the thermal stability was noticed to be decreased implying the presence of nanocrystals on the amorphous powder after ball milling and the nanocrystal amount tend to be higher when more milling cycles were applied.


Construction Effects On The Side Shear Of Drilled Shafts, Lucas Caliari De Lima Nov 2017

Construction Effects On The Side Shear Of Drilled Shafts, Lucas Caliari De Lima

USF Tampa Graduate Theses and Dissertations

Design methods for side shear of drilled shafts, including the resistance factors that should be applied, do not account for any specific construction procedure. Instead, design often relies on analysis of case studies which include all construction methods used in each geomaterial type (e.g. clays, sands and rocks), or on parametric analysis. Nonetheless, literature suggests that different construction procedures result in varying side shear.

This research investigated 2 types of construction: (1) slurry stabilization in sandy soils using bentonite and polymer products that are commonly used on the field, with exposure times from near 0h to 96h, and (2) temporary …


Bridge Build, Andrew Little Nov 2017

Bridge Build, Andrew Little

Student Scholarship

Bridge build design that includes not only a building process, but a research paper to make the best build possible as well.


Quantifying Effectiveness Of Streambank Stabilization Practices On Cedar River, Nebraska, Naisargi Dave, Aaron R. Mittelstet Nov 2017

Quantifying Effectiveness Of Streambank Stabilization Practices On Cedar River, Nebraska, Naisargi Dave, Aaron R. Mittelstet

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Excessive sediment is a major pollutant to surface waters worldwide. In some watersheds, streambanks are a significant source of this sediment, leading to the expenditure of billions of dollars in stabilization projects. Although costly streambank stabilization projects have been implemented worldwide, long-term monitoring to quantify their success is lacking. There is a critical need to document the long-term success of streambank restoration projects. The objectives of this research were to (1) quantify streambank retreat before and after the stabilization of 18 streambanks on the Cedar River in North Central Nebraska, USA; (2) assess the impact of a large flood event; …


Bond Of Steel Reinforcement With Microwave Cured Concrete Repair Mortars, P. S. Mangat, Shahriar Abubakri, Konstantinos Grigoriadis Nov 2017

Bond Of Steel Reinforcement With Microwave Cured Concrete Repair Mortars, P. S. Mangat, Shahriar Abubakri, Konstantinos Grigoriadis

Henry M. Rowan College of Engineering Departmental Research

This paper investigates the effect of microwave curing on the bond strength of steel reinforcement in concrete repair. Pull-out tests on plain mild steel reinforcement bars embedded in four repair materials in 100 mm cube specimens were performed to determine the interfacial bond strength. The porosity and pore structure of the matrix at the steel interface, which influence the bond strength, were also determined. Test results show that microwave curing significantly reduces the bond strength of plain steel reinforcement. The reduction relative to normally cured (20 °C, 60% RH) specimens is between 21 and 40% with low density repair materials …


Ptfe-Based Microreactor System For The Continuous Synthesis Of Full-Visible-Spectrum Emitting Cesium Lead Halide Perovskite Nanocrystals, Chengxi Zhang, Weiling Luan, Yuhang Yin, Fuqian Yang Nov 2017

Ptfe-Based Microreactor System For The Continuous Synthesis Of Full-Visible-Spectrum Emitting Cesium Lead Halide Perovskite Nanocrystals, Chengxi Zhang, Weiling Luan, Yuhang Yin, Fuqian Yang

Chemical and Materials Engineering Faculty Publications

Colloidal perovskite nanocrystals comprised of all inorganic cesium lead halide (CsPbX3, X = Cl, Br, I or a mixture thereof) have potential as optical gain materials due to their high luminescence efficiency. In this work, cesium lead halide nanocrystals are continuously synthesized via a microreactor system consisting of poly(tetrafluoroethylene) (PTFE) capillaries. The synthesized nanocrystals possess excellent optical properties, including a full width at half maximum of 19–35 nm, high fluorescence quantum yield of 47.8–90.55%, and photoluminescence emission in the range of 450–700 nm. For the same precursor concentrations, the photoluminescence emission peak generally increases with increasing reaction temperature, …