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Full-Text Articles in Materials Science and Engineering

Micro-Mechanics Simulation Tool Optimization, Ruixuan Ren, Marisol Koslowski Aug 2014

Micro-Mechanics Simulation Tool Optimization, Ruixuan Ren, Marisol Koslowski

The Summer Undergraduate Research Fellowship (SURF) Symposium

Crystalline films grown epitaxially on substrates consisting of a different crystalline material are of considerable interest in optoelectronic devices and the semiconductor industry. One way to progress in this field is to develop simulation tools based on specially designed numerical method. A nanoHUB simulation tool was developed based on the phase field theory, which considers the propagation of dislocations inside the crystalline film. However, the current tool needs several improvements to be more realistic and user-friendly. First, the inputs of the simulation tool are adjusted so that the user can use this tool directly without any additional calculation. The output …


He+ Ion Irradiation On Tungsten Surface In Extreme Conditions, George I. Joseph, Jitendra Tripathi, Sivanandan S. Harilal, Ahmed Hassanein Aug 2014

He+ Ion Irradiation On Tungsten Surface In Extreme Conditions, George I. Joseph, Jitendra Tripathi, Sivanandan S. Harilal, Ahmed Hassanein

The Summer Undergraduate Research Fellowship (SURF) Symposium

Higher melting point (3695K), lower sputtering yield and most importantly, lower in-bulk, and co-deposit retention at elevated temperature makes tungsten (W) as a potential candidate for plasma-facing component (PFC) in the international thermonuclear experimental reactor (ITER)-divertor. Helium ion (He+) bombardment on W can cause wide variety of microstructural evolution, such as dislocation loops, helium holes/bubbles and fibre-form nanostructures (Fuzz) etc. In this work, 100 eV He+ ion irradiation, at temperature ranges from 500°C to 1000°C, will be performed on mechanically polished mirror like W surfaces. The surface modification and compositional analysis, due to ion irradiation, will be …


Investigation Of Fracture And Healing Behavior Of Thermoreversible Gels Via Oscillation Rheology, Krithika Subramaniam, Travis Thornell, Kendra Erk Aug 2014

Investigation Of Fracture And Healing Behavior Of Thermoreversible Gels Via Oscillation Rheology, Krithika Subramaniam, Travis Thornell, Kendra Erk

The Summer Undergraduate Research Fellowship (SURF) Symposium

Thermoreversible gels have the unique ability to self-heal, or repair themselves, once they are fractured. They are physically cross-linked, thus providing them with the capability to reform their broken bonds as a function of temperature. The objective of this project is to determine the extent of the gels’ recovery. If self-healing does in fact occur, these gels can be applied in various industries, including medicine for drug delivery or paints and coatings. The tri-block polymer poly(methyl methacrylate)-poly(n-butyl acrylate)-poly(methyl methacrylate) (PMMA-PnBA-PMMA) was heated and stirred with 2-ethyl-1-hexanol to create a polymer gel. Through the use of a rheometer, a shear stress …


Synthesis And Thermoelectric Properties Of Cusbs2, Tianyue Gao, Haiyu Fang, Yue Wu Aug 2014

Synthesis And Thermoelectric Properties Of Cusbs2, Tianyue Gao, Haiyu Fang, Yue Wu

The Summer Undergraduate Research Fellowship (SURF) Symposium

Copper antimony sulfide, CuSbS2 nanoparticles have a large potential of being a good thermoelectric material because they are made up of earth abundant elements. Thermoelectric materials can convert thermal energy into electricity, so that the wasted energy can be saved. Also, by using this earth abundant material, we can make thermoelectric materials much cheaper. The hypothesis of this study is that CuSbS2 could have a large Seebeck coefficient, one of the most important factors of thermoelectric materials, because of the complexity of its band structure. The other hypothesis is that thermal transport could be significantly suppressed through nanostructuring. There are …


Finite Element Analysis Of Bolted Connections Under Fire, Ke Liu, Qiaqia Zhu, Amit H. Varma Aug 2014

Finite Element Analysis Of Bolted Connections Under Fire, Ke Liu, Qiaqia Zhu, Amit H. Varma

The Summer Undergraduate Research Fellowship (SURF) Symposium

Over the course of human history, fire disasters are one of the major catastrophes that causes loss of lives and properties. In order to ensure building safety against fire, civil engineers seek to understand the behavior of structures at high temperatures. Moreover, they need to study the behavior of bolted connections, given the important role it plays in steel structures. Sarraj (2007) proposed a plate-bearing computational model used to describe this behavior; however, it has never been experimentally verified. Prior to this specific project, a series of single-bolted connection tests at 400°C and 600°C were conducted in the Bowen Laboratory …


Polymer-Based Thermoelectric Devices, Stuart W. Hilsmier, Edward P. Tomlinson, Bryan Boudouris Aug 2014

Polymer-Based Thermoelectric Devices, Stuart W. Hilsmier, Edward P. Tomlinson, Bryan Boudouris

The Summer Undergraduate Research Fellowship (SURF) Symposium

Currently, over 50% of all energy generated in the US is lost as waste heat, and thermoelectric generators offer a promising means to recoup some of this energy, if their efficiency is improved. While organic thermoelectric materials lack the efficiency of their inorganic counterparts, they are composed of highly abundant resources and have low temperature processing conditions. Recently, a new class of redox-active polymers, radical polymers, has exhibited high electrical conductivity in an entirely amorphous medium. In addition, these radical polymers have a simple synthetic scheme and can be highly tunable to provide desired electrical properties. In this study, the …


Characterization Of Mechanical Properties Displayed In Body Armor Ballistic Fibers, Dawei Li, Matthew Hudspeth, Weinong Wayne Chen Aug 2014

Characterization Of Mechanical Properties Displayed In Body Armor Ballistic Fibers, Dawei Li, Matthew Hudspeth, Weinong Wayne Chen

The Summer Undergraduate Research Fellowship (SURF) Symposium

The current body armor systems manufactured using ballistic fibers are not performing as theoretical results predict and are causing injuries. The actual maximum projectile penetration speed that the body armor can endure is significantly lower than the theoretical maximum speed, thus causing a costly build-test relationship that is not aided with modeling design efforts. The main aim of this research is to determine the maximum penetration speeds for ballistic yarns and fabrics. Secondary aim is to examine the common assumption that during transverse impact, single fiber is under pure tension and shear stress is negligible. To examine aforementioned assumption, fibers …


Rheo-Piv Investigation Of Fracture And Self-Healing In A Triblock Copolymer Gel, Benjamin A. Helfrecht, Travis L. Thornell, Kendra A. Erk Aug 2014

Rheo-Piv Investigation Of Fracture And Self-Healing In A Triblock Copolymer Gel, Benjamin A. Helfrecht, Travis L. Thornell, Kendra A. Erk

The Summer Undergraduate Research Fellowship (SURF) Symposium

Physically associating polymer gels have shown the ability to heal after failure, making them promising candidates for various medical applications or consumer products. However, the processes by which these materials self-heal is not well-understood. This study seeks to explain the self-healing behavior of the triblock copolymer poly(methyl methacrylate)-poly(n-butyl acrylate)-poly(methyl methacrylate), or PMMA-PnBA-PMMA, by probing the material’s post-fracture behavior with rheometry and particle image velocimetry (PIV). The self-healing behavior was studied by deforming each gel in shear until failure multiple times with “recovery” periods in-between. PIV was used to verify the occurrence of each fracture in both time and space. Stress …


Simulation Of Bio-Inspired Porous Battery Electrodes, Raju Gupta, R. Edwin Garcia, Rui Tu Aug 2014

Simulation Of Bio-Inspired Porous Battery Electrodes, Raju Gupta, R. Edwin Garcia, Rui Tu

The Summer Undergraduate Research Fellowship (SURF) Symposium

Advancement of technology has led to the increase in use of electronic devices. However, longer life of the rechargeable battery used in electronic devices is one of the biggest issue and demand in the world of electronic devices at present. Battery's performance is affected by the orientation, arrangement, shape and size, and porosity of the materials out of which battery electrodes are made. The goal of this project is to develop a set of numerical libraries that allow developing material micro structures that will allow increasing the performance of rechargeable batteries. We focused on the development of an algorithm that …


Development Of Electron Microscopy Analysis And Simulation Tools For Nanohub, Mingxuan Lu, Chang Wan Han, Benjamin P. Haley, Volkan Ortalan Aug 2014

Development Of Electron Microscopy Analysis And Simulation Tools For Nanohub, Mingxuan Lu, Chang Wan Han, Benjamin P. Haley, Volkan Ortalan

The Summer Undergraduate Research Fellowship (SURF) Symposium

Electron microscopy has a crucial role in the field of materials science and structural biology. Although electron microscopy gives lots of important results and findings, some additional simulations and image processing/reconstruction is required to get more information from the data that are collected from the experiments. For this purpose, researchers are using IMOD1 and QSTEM2 for electron microscopy analysis and simulation. IMOD is a set of programs used for tomographic reconstruction and 3D visualization and QSTEM is used for quantitative simulations of TEM and STEM images. However, IMOD and QSTEM are hard to install or use for beginners …


Development Of A Nanomanufacturing Process To Produce Atomically Thin Black Phosphorus, Andrew Stephens, Zhe Luo, Xianfan Xu Aug 2014

Development Of A Nanomanufacturing Process To Produce Atomically Thin Black Phosphorus, Andrew Stephens, Zhe Luo, Xianfan Xu

The Summer Undergraduate Research Fellowship (SURF) Symposium

Atomically thin black phosphorus (phosphorene) has both unique and desirable properties that differ from bulk black phosphorus. Unlike graphene, phosphorene has a bandgap, which makes it potentially useful for applications in the next generation of transistors. Large-scale applications of phosphorene, like other 2D materials, are limited by current production methods. The most common method of making phosphorene is mechanical exfoliation, which can only produce small and irregular quantities. In this work we investigate a top-down method of producing phosphorene by using a scanning ultrafast laser to thin black phosphorus flakes. Because the bandgap of phosphorene increases as layers are removed, …


Surgical Adhesive From Mussel Mimetic Polymer, Jenna Desousa, Cori Jenkins, Jonathan Wilker Aug 2014

Surgical Adhesive From Mussel Mimetic Polymer, Jenna Desousa, Cori Jenkins, Jonathan Wilker

The Summer Undergraduate Research Fellowship (SURF) Symposium

Injuries involving damaged tissues are currently repaired through an invasive technique involving the use of screws, plates and sutures as support, which can damage these tissues. The biomedical field currently lacks an adhesive that can replace harmful implants. A surgical adhesive can provide a quick and easy alternative, which will minimize the risk of damaging healthy tissue in surgery. Inspiration for such materials can be found by looking at marine mussels as they are able to stick to nearly any surface, even in wet environments. Marine mussels affix themselves to different surfaces using adhesive plaques consisting of various proteins. Polymer …


Investigation Of The Performance Of Different Types Of Zirconium Microstructures Under Extreme Irradiation Conditions, Eric M. Acosta, Osman J. El-Atwani Aug 2014

Investigation Of The Performance Of Different Types Of Zirconium Microstructures Under Extreme Irradiation Conditions, Eric M. Acosta, Osman J. El-Atwani

The Summer Undergraduate Research Fellowship (SURF) Symposium

The safe and continued operation of the US nuclear power plants requires improvement of the radiation resistant properties of materials used in nuclear reactors. Zirconium is a material of particular interest due to its use in fuel cladding. Studies performed on other materials have shown that grain boundaries can play a significant role on the radiation resistant properties of a material. Thus, the focus of our research is to investigate the performance of different zirconium microstructures under irradiation conditions similar to those in commercial nuclear reactors. Analysis of the surface morphology of zirconium both pre- and post-irradiation was conducted with …


Characterization Of Swelling Ratio And Water Content Of Hydrogels For Cartilage Engineering Applications, Emily E. Gill, Renay S.-C. Su, Julie C. Liu Aug 2014

Characterization Of Swelling Ratio And Water Content Of Hydrogels For Cartilage Engineering Applications, Emily E. Gill, Renay S.-C. Su, Julie C. Liu

The Summer Undergraduate Research Fellowship (SURF) Symposium

Due to the high prevalence of arthritis and cartilage-related injuries, tissue engineers are studying ways to grow cartilage tissue replacements. Resilin, an elastomeric protein found in insect cuticles, is known for its extraordinary resilience and elasticity. In previous studies, recombinant resilin-based hydrogels, or cross-linked protein networks, exhibited potential for use in cartilage tissue scaffolds. Our lab successfully developed resilin-based proteins with a sequence based on the mosquito gene and showed that resilin-based hydrogels possess mechanical properties of the same order of magnitude as native articular cartilage. In addition, these mechanical properties can be controlled by changing the protein concentration. To …


Simulation Of Bio-Inspired Porous Battery Separators, Yumeng Xie, Edwin Garcia, Aniruddha Jana Aug 2014

Simulation Of Bio-Inspired Porous Battery Separators, Yumeng Xie, Edwin Garcia, Aniruddha Jana

The Summer Undergraduate Research Fellowship (SURF) Symposium

Li-Ion rechargeable battery is one of the most-used rechargeable batteries around the industry of the world. The battery is most used in most electronic devices, electrical cars. But the battery separator is one of the mainly problem that limits the service life. If we can find the way to improve the performance of the battery separator, we can highly increase the service life of the Li-Ion battery. The goal of the project 'Simulation of Bio-Inspired Porous Battery Separators' is to generate a tool for users in order to create computer models of bio-inspired porous structures that resemble porous separators layer …


Microstructure Development Of Granular System During Compaction, Chen Shang, Marcial Gonzalez Aug 2014

Microstructure Development Of Granular System During Compaction, Chen Shang, Marcial Gonzalez

The Summer Undergraduate Research Fellowship (SURF) Symposium

Granular materials is the second most manipulated material in the industry today. They are easy to transport and more and more newly developed materials cannot stand the process of traditional casting, like energetic materials and bio-materials, but will survive the powder compaction process. Having a better understanding of the microstructure development of granular systems during compaction process, especially for particles that will heavily deform under loading, will give an insight of how to better process the powders to produce materials with overall better performance comparing to bulk materials. The main theory and mechanism applied are Hertz law and nonlocal contact …


Biological Implications Of Satellite Cells For Scaffold-Based Muscle Regenerative Engineering, Maggie R. Del Ponte, Charter Chain, Meng Deng Dr., Feng Yue Dr., Shihuan Kuang Dr. Aug 2014

Biological Implications Of Satellite Cells For Scaffold-Based Muscle Regenerative Engineering, Maggie R. Del Ponte, Charter Chain, Meng Deng Dr., Feng Yue Dr., Shihuan Kuang Dr.

The Summer Undergraduate Research Fellowship (SURF) Symposium

Satellite cells are anatomically localized along the surface of muscle fibers and have been regarded as a population of muscle-specific progenitors that are responsible for muscle regeneration. In response to muscle injuries, satellite cells are activated to enter the cell cycle, then proliferate and differentiate into mature muscle cells to regenerate damaged myofibers. Unfortunately, this natural repair mechanism is interrupted in conditions such as muscle degenerative diseases or volumetric muscle loss. The function of stem cells is regulated by signals from their local microenvironment which is called the stem cell niche. Current satellite cell-based strategies such as direct cell transplantation …


The Role Of Metal Oxide Layers In The Sensitivity Of Lactate Biosensors Subjected To Oxygen-Limited Conditions, Elizabeth Andreasen, Lia Stanciu, Aytekin Uzunoglu Aug 2014

The Role Of Metal Oxide Layers In The Sensitivity Of Lactate Biosensors Subjected To Oxygen-Limited Conditions, Elizabeth Andreasen, Lia Stanciu, Aytekin Uzunoglu

The Summer Undergraduate Research Fellowship (SURF) Symposium


Amperometric lactate biosensors are used to detect lactate concentration in blood and tissues, which is integral in identifying cyanide poisoning, septic shock, and athletic condition. The construction of lactate biosensors with high sensitivity, selectivity, and stability is imperative to diagnose and determine these medical conditions. Lactate detection is currently limited to oxygen-rich environments due to the fact that oxygen is a limiting factor in the lactate reaction. To circumvent this problem, researchers have developed mediators or alternate, oxygen-free enzymes to improve sensitivity. In our study, ceria (CeO2) with high oxygen storage capacity (OSC) was introduced to the enzyme …


Design And Fabrication Of A Novel Electrospinning System For Musculoskeletal Tissue Regeneration, Carter L. Chain, Maggie R. Del Ponte, Meng Deng, Feng Yue, Shihuan Kuang Aug 2014

Design And Fabrication Of A Novel Electrospinning System For Musculoskeletal Tissue Regeneration, Carter L. Chain, Maggie R. Del Ponte, Meng Deng, Feng Yue, Shihuan Kuang

The Summer Undergraduate Research Fellowship (SURF) Symposium

Disease and injury to human tissue, especially musculoskeletal tissue, is a prevalent concern to the public, affecting millions of people each year. Current treatment options involving autografts and allografts are hindered by limited availability and risk of immunogenicity, respectively. In order to overcome these limitations, a transdisiplinary regenerative engineering strategy has emerged with a focus on the development of biomimetic scaffolds that closely mimic the properties of the native tissues. For example, the structure of muscle tissue is characterized by oriented muscle fibers. However, fabrication of aligned nanofiber structures that mimic the anisotropic organization of muscle presents significant engineering challenges. …


Building Predictive Chemistry Models, Christopher Browne, Nicolas Onofrio, Alejandro Strachan Aug 2014

Building Predictive Chemistry Models, Christopher Browne, Nicolas Onofrio, Alejandro Strachan

The Summer Undergraduate Research Fellowship (SURF) Symposium

Density Functional Theory (DFT) simulations allow for sophisticated modeling of chemical interactions, but the extreme computational cost makes it inviable for large scale applications. Molecular dynamics models, specifically ReaxFF, can model much larger simulations with greater speed, but with lesser accuracy. The accuracy of ReaxFF can be improved by comparing predictions of both methods and tuning ReaxFF’s parameters. Molecular capabilities of ReaxFF were gauged by simulating copper complexes in water over a 200 ps range, and comparing energy predictions against ReaxFF. To gauge solid state capabilities, volumetric strain was applied to simulated copper bulk and the strain response functions used …


Dynamic Response Of Textile Material Under Transverse Impact, Yuchen Zheng, Matthew C. Hudspeth, Weinong W. Chen Aug 2014

Dynamic Response Of Textile Material Under Transverse Impact, Yuchen Zheng, Matthew C. Hudspeth, Weinong W. Chen

The Summer Undergraduate Research Fellowship (SURF) Symposium

Textile materials, such as Dyneema and Kevlar, are the major raw materials for state of the art military or personal security armor vests. However, in impact experiments, actual observed penetration speed is much lower than theoretically predicted penetration speed. Each armor vest is composed of high performance yarns which are woven together to form fabrics, which when stacked together form a vest. Understanding penetration behavior of yarns is essential to evaluate the performance of fabric, which will be useful for the design of better vests. The project is composed of three parts: static experiments, dynamic yarn experiments and dynamic fabric …


Fiber Length And Orientation In Long Carbon Fiber Thermoplastic Composites, Imad Hanhan, Connor Sullivan, Bhisham Sharma, Michael Sangid Aug 2014

Fiber Length And Orientation In Long Carbon Fiber Thermoplastic Composites, Imad Hanhan, Connor Sullivan, Bhisham Sharma, Michael Sangid

The Summer Undergraduate Research Fellowship (SURF) Symposium

Carbon fiber composites have become popular in aerospace applications because of their lightweight yet strong material properties. The injection molding process can be used to produce discontinuous fiber composites using less time and resources than traditional methods, thereby broadening carbon fiber composites’ applications in different industries. Utilization of longer fibers offers more load carrying capability and superior strength properties for injected molded composites. Since the fiber length and the orientation distribution in Long Fiber Thermoplastics (LFTs) directly affects LFT composites’ material properties, there is a need to study the microstructure of LFTs and characterize fiber length and orientation distributions. Therefore, …


Bio-Inspired Helicoidal Composites: 3d Printing And Experiments, Michael E. Jones, Pablo Zavattieri, Nobphadon Suksangpanya Aug 2014

Bio-Inspired Helicoidal Composites: 3d Printing And Experiments, Michael E. Jones, Pablo Zavattieri, Nobphadon Suksangpanya

The Summer Undergraduate Research Fellowship (SURF) Symposium

Materials that are impact resistant enough for personal protection in sports, transport, and combat are not also lightweight, strong, tough, and impact tolerant. Nature can provide inspiration for novel materials that can meet these needs. The hierarchical composite of the stomatopod’s, or mantis shrimp’s, dactyl club has been shown to have high impact resistance and damage tolerance due to its helicoidal fiber reinforcement(1,2). Analyzing helicoidal composites of different pitch angles (angles between adjacent rows of fibers) under quasi-static, displacement-controlled loading has provided insights into the fracture mechanisms of the composite structure and how they affect the macroscopic properties of the …


Molecular Exploration Tool, Weiyi Cao, Nicolas Onofrio, Alejandro Strachan Aug 2014

Molecular Exploration Tool, Weiyi Cao, Nicolas Onofrio, Alejandro Strachan

The Summer Undergraduate Research Fellowship (SURF) Symposium

Density Functional Theory (DFT) which is based on quantum mechanics theory has been broadly used to compute the energy and the structure of molecules and solids. However, the DFT method is limited when running calculations for a large system and only thousands of atoms can be solved. Alternatively, Molecular Dynamics (MD) simulation can be used to investigate the properties of the atomic system for large systems in the classical mechanics approximation. When running the MD simulation, the electronic structure is approximated by Force Fields (FF) which can be parametrized against DFT calculations. Nevertheless, the accuracy of the MD results and …


Implementing The ‘Frozen Potential’ Approach On Adept To Analyze Thin Film Solar Cells, Abhirit Kanti, Raghu Vamsi Krishna Chavali, Mark S. Lundstrom Phd, Muhammad A. Alam Phd Aug 2014

Implementing The ‘Frozen Potential’ Approach On Adept To Analyze Thin Film Solar Cells, Abhirit Kanti, Raghu Vamsi Krishna Chavali, Mark S. Lundstrom Phd, Muhammad A. Alam Phd

The Summer Undergraduate Research Fellowship (SURF) Symposium

Thin film solar cells have higher absorption coefficients than traditional Silicon solar cells. This means that lesser material is required to produce the same power output for a given intensity of solar illumination. As a result, they are less expensive, easier to install and have a wider range of applications. Analyzing the performance of cells requires separating the current into the photocurrent and the injection current based on the ‘Superposition Principle’. For thin film solar cells, this cannot be done using the conventional method. This is because these components are interdependent, and so modeling one’s behavior requires understanding the other. …


Crack Propagation Simulation Tool, Nilofer Rajpurkar, Hojin Kim, Alejandro Strachan Aug 2014

Crack Propagation Simulation Tool, Nilofer Rajpurkar, Hojin Kim, Alejandro Strachan

The Summer Undergraduate Research Fellowship (SURF) Symposium

In the massively engineered world that exists today, understanding material behavior is of paramount importance in caring for human safety in design. Molecular dynamic simulations on crack propagation through materials allow visualization of material behavior under stress. The tool, developed by the nanoHUB group as a part of the Network for Computational Nanotechnology at Purdue University, makes performing such simulations accessible to undergraduate students, highly qualified researchers, and all those in between. First, the input deck for the simulation parameters was simplified from the complex, language-specific code into a simple, user-friendly Graphic User Interface (GUI). Several interesting example cases were …


The Correlation Of Chloride Diffusion Coefficient And Concrete Maturity Value And Its Application In Hong Kong–Zhuhai–Macao Bridge Engineering, Pengping Li, Shengnian Wang, Jianbo Xiong, Rui Chai, Yu Yan Jul 2014

The Correlation Of Chloride Diffusion Coefficient And Concrete Maturity Value And Its Application In Hong Kong–Zhuhai–Macao Bridge Engineering, Pengping Li, Shengnian Wang, Jianbo Xiong, Rui Chai, Yu Yan

International Conference on Durability of Concrete Structures

The correlation of chloride diffusion coefficient and concrete maturity value within 56 days of curing was investigated by the chemically combined water content method, rapid chloride migration (RCM) test, and concrete maturity test. The experimental results showed that chloride diffusion coefficient of concretes decreased not only with increasing curing ages but also with increasing curing temperature, which can promote the hydration degree of cementitous materials. There is a significant correlation between the chloride diffusion coefficient of indoor cured specimens and the concrete maturity value when expressed as a power function (R2 = 0.976). In addition, the calculated values of …


Finite Volume Numerical Analysis Of The Thermal Property Of Cellular Concrete Based On Two And Three Dimensional X-Ray Computerized Tomography Images, She Wei, Yang Yonggan, Xie Deqing, Zhang Yunsheng Jul 2014

Finite Volume Numerical Analysis Of The Thermal Property Of Cellular Concrete Based On Two And Three Dimensional X-Ray Computerized Tomography Images, She Wei, Yang Yonggan, Xie Deqing, Zhang Yunsheng

International Conference on Durability of Concrete Structures

Cellular concrete is one kind of lightweight concrete, which are widely used in thermal insulation engineering project. In this study, a three dimensional (2D and 3D) finite-volume-based models was developed for analyzing the heat transfer mechanisms through the porous structures of cellular concretes under steady-state heat transfer condition and also for investigating the differences between 2D and 3D modeling results. 2D and 3D reconstructed pore networks were generated from the microstructural information measured by a 3D image captured by X-ray computerized tomography (X-CT). In addition, the 3D-computed value of the effective thermal conductivity was found to be in better agreement …


On Utilization Of Elliptical Rings In Assessing Cracking Tendency Of Concrete, Xiangming Zhou, Olayinka G. Oladiran, Wei Dong Jul 2014

On Utilization Of Elliptical Rings In Assessing Cracking Tendency Of Concrete, Xiangming Zhou, Olayinka G. Oladiran, Wei Dong

International Conference on Durability of Concrete Structures

A new experimental method by utilizing elliptical rings to replace circular rings recommended by ASTM and AASHTO was explored for assessing cracking potential of concrete and other cement-based materials under restrained condition. A series of thin and thick elliptical concrete rings were tested alongside circular ones until cracking. Cracking age, position, and propagation were carefully examined. It is found that thin elliptical rings with appropriate geometry can initiate cracks quicker than circular ones, which is desirable for accelerating the ring test. However, thick elliptical rings seem not to exhibit a desirable geometry effect of accelerating ring test compared with circular …


Influence Of Controlled Permeability Formwork On The Permeability Of Concrete, Wei Lin, Q. Jiang, J. Liu, J. Liu Jul 2014

Influence Of Controlled Permeability Formwork On The Permeability Of Concrete, Wei Lin, Q. Jiang, J. Liu, J. Liu

International Conference on Durability of Concrete Structures

Corrosion of steel reinforcement related to the intrusion of chloride ion is still the main threats to the durability of concrete structure, especially in marine environment. For the purpose of delaying the Cl concentration at the surface of steel reinforcement reaching the critical value leading to initial corrosion, the permeability of concrete is usually improved by optimizing the concrete mixture to achieve high compatibility as well as optimized pore structure. In recent years, controlled permeability formwork (CPF) which was originally developed to obtain much smoother surface of the concrete proves to promote the service performance of the concrete by …