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Full-Text Articles in Engineering

An Investigation On The Effects Of Cellulose Nanofibrils On The Performance Of Cement Based Composites, Hosain Haddad Kolour Dec 2019

An Investigation On The Effects Of Cellulose Nanofibrils On The Performance Of Cement Based Composites, Hosain Haddad Kolour

Electronic Theses and Dissertations

Cellulose nanofibrils (CNFs) are hydrophilic biodegradable nanoparticles (typically, less than 0.2 mm in length and 20-50 nm in width) that can be extracted from various plants, trees, and recycled paper stock. Their low density, low toxicity, relatively low cost, high aspect ratio, and high specific surface enable functionalization. In this work, the effects of CNFs on selected properties of cement paste, mortar, and concrete were investigated. For the cement pastes, rheology tests using a simple rheometer showed a reduction in workability as CNF dosage increased. Free shrinkage tests showed an increase in shrinkage at high w/c ratios but ...


Freeze-Thaw Resistance Of Concrete: Insight From Microstructural Properties, Sam Adu-Amankwah, Leon Black Dr, M Zajac, J Skoceck, M Ben Haha Nov 2019

Freeze-Thaw Resistance Of Concrete: Insight From Microstructural Properties, Sam Adu-Amankwah, Leon Black Dr, M Zajac, J Skoceck, M Ben Haha

International Conference on Durability of Concrete Structures

Composite cements offer low carbon alternatives to conventional CEM I. These binders also generally tend to perform better than CEM I in aggressive chemical environments. However, their freeze-thaw resistance, evident through surface scaling and internal damage is usually impaired. Postulated theories on freeze-thaw induced damage do not fully explain the origin of this weakness in composite cement concretes.

This paper systematically presents the phase assemblage changes associated with the freeze-thaw of concrete specimen made from composite cements with and without limestone. The freeze-thaw test was performed on concrete according to CIF method based on CEN/TR 15177 and the corresponding ...


Innovative Technologies In The Manufacture Of Compositive Lining Materials For Shoe Industry, X.N. Ahmadov, N.B. Mirzayev, U.M. Maksudova, Z. Abduraximov Sep 2019

Innovative Technologies In The Manufacture Of Compositive Lining Materials For Shoe Industry, X.N. Ahmadov, N.B. Mirzayev, U.M. Maksudova, Z. Abduraximov

Textile Journal of Uzbekistan

In recent years, the number of basic hygiene requirements for special-purpose shoes has increased the requirements for ensuring the comfortable properties of shoes. All these requirements for shoes are directly related to the materials of the upper and lining, as well as to the internal materials of the bottom of the shoe. These materials are in direct contact with the foot and the hygienic properties of the latter form the properties of the shoe itself. Currently, a number of high-tech composite materials are used as cushioning materials for the manufacture of leather products, characterized by a variety of means and ...


Hydcem: A New Cement Hydration Model, Niall Holmes, Denis Kelliher, Mark Tyrer Aug 2019

Hydcem: A New Cement Hydration Model, Niall Holmes, Denis Kelliher, Mark Tyrer

Conference papers

Hydration models are useful to predict, understand and describe the behaviour of different cementitious-based systems. They are indispensable for undertaking long-term performance and service life predictions for existing and new products for generating quantitative data in the move towards more sustainable cements while optimising natural resources. One such application is the development of cement-based thermoelectric applications.

HYDCEM is a new model to predict the phase assemblage, degree of hydration, heat release and changes in pore solution chemistry over time for cements undergoing hydration for any w/c ratio and curing temperatures up to 450C. HYDCEM, written in MATLAB, is aimed ...


Fabrication And Characterization Of AlₓCrcufeni₂ High-Entropy Alloys Coatings By Laser Metal Deposition, Wenyuan Cui, Xinchang Zhang, Lan Li, Yitao Chen, Tan Pan, Frank W. Liou Aug 2019

Fabrication And Characterization Of AlₓCrcufeni₂ High-Entropy Alloys Coatings By Laser Metal Deposition, Wenyuan Cui, Xinchang Zhang, Lan Li, Yitao Chen, Tan Pan, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

High-entropy alloys (HEAs) are becoming new hot spots in the metallic materials community, which are defined to contain equiatomic or close-to-equiatomic compositions. HEAs can possess many interesting mechanical properties, and in particular, they have the great potential to be used as coating materials requiring high hardness and wear resistance. In this study, the feasibility of fabrication AlₓCrCuFeNi₂ (x=0,0.75) HEAs was investigated via laser metal deposition from elemental powders. The microstructure, phase structure, and hardness were studied by an optical microscope, scanning electron microscopy with energy dispersive spectroscopy (SEM/EDS), electron backscatter diffraction (EBSD) and Vickers hardness tester ...


Liquid Metal-Elastomer Soft Composites With Independently Controllable And Highly Tunable Droplet Size And Volume Loading, Ravi Tutika, Steven Kmiec, A. B. M. Tahidul Haque, Steve W. Martin, Michael D. Bartlett May 2019

Liquid Metal-Elastomer Soft Composites With Independently Controllable And Highly Tunable Droplet Size And Volume Loading, Ravi Tutika, Steven Kmiec, A. B. M. Tahidul Haque, Steve W. Martin, Michael D. Bartlett

Michael Bartlett

Soft composites are critical for soft and flexible materials in energy harvesting, actuators, and multifunctional devices. One emerging approach to create multifunctional composites is through the incorporation of liquid metal (LM) droplets such as eutectic gallium indium (EGaIn) in highly deformable elastomers. The microstructure of such systems is critical to their performance, however, current materials lack control of particle size at diverse volume loadings. Here, we present a fabrication approach to create liquid metal-elastomer composites with independently controllable and highly tunable droplet size (100 nm ≦ D ≦ 80 μm) and volume loading (0 ≦ φ ≦ 80%). This is achieved through a combination ...


A Study On Ultrasonic Energy Assisted Metal Processing : Its Correeltion With Microstructure And Properties, And Its Application To Additive Manufacturing., Anagh Deshpande May 2019

A Study On Ultrasonic Energy Assisted Metal Processing : Its Correeltion With Microstructure And Properties, And Its Application To Additive Manufacturing., Anagh Deshpande

Electronic Theses and Dissertations

Additive manufacturing or 3d printing is the process of constructing a 3-dimensional object layer-by-layer. This additive approach to manufacturing has enabled fabrication of complex components directly from a computer model (or a CAD model). The process has now matured from its earlier version of being a rapid prototyping tool to a technology that can fabricate service-ready components. Development of low-cost polymer additive manufacturing printers enabled by open source Fused Deposition Modeling (FDM) printers and printers of other technologies like SLA and binder jetting has made polymer additive manufacturing accessible and affordable. But the metal additive manufacturing technologies are still expensive ...


Intelligent Machine Learning: Tailor-Making Macromolecules, Yousef Mohammadi, Mohammad Reza Saeb, Alexander Penlidis, Esmaiel Jabbari, Florian J. Stadler, Philippe Zinck, Krzysztof Matyjaszewski Apr 2019

Intelligent Machine Learning: Tailor-Making Macromolecules, Yousef Mohammadi, Mohammad Reza Saeb, Alexander Penlidis, Esmaiel Jabbari, Florian J. Stadler, Philippe Zinck, Krzysztof Matyjaszewski

Faculty Publications

Nowadays, polymer reaction engineers seek robust and effective tools to synthesize complex macromolecules with well-defined and desirable microstructural and architectural characteristics. Over the past few decades, several promising approaches, such as controlled living (co)polymerization systems and chain-shuttling reactions have been proposed and widely applied to synthesize rather complex macromolecules with controlled monomer sequences. Despite the unique potential of the newly developed techniques, tailor-making the microstructure of macromolecules by suggesting the most appropriate polymerization recipe still remains a very challenging task. In the current work, two versatile and powerful tools capable of effectively addressing the aforementioned questions have been proposed ...


Intelligent Machine Learning: Tailor-Making Macromolecules, Yousef Mohammadi, Mohammad Reza Saeb, Alexander Penlidis, Esmaiel Jabbari, Florian J. Stadler, Philippe Zinck, Krzysztof Matyjaszewski Apr 2019

Intelligent Machine Learning: Tailor-Making Macromolecules, Yousef Mohammadi, Mohammad Reza Saeb, Alexander Penlidis, Esmaiel Jabbari, Florian J. Stadler, Philippe Zinck, Krzysztof Matyjaszewski

Faculty Publications

Nowadays, polymer reaction engineers seek robust and effective tools to synthesize complex macromolecules with well-defined and desirable microstructural and architectural characteristics. Over the past few decades, several promising approaches, such as controlled living (co)polymerization systems and chain-shuttling reactions have been proposed and widely applied to synthesize rather complex macromolecules with controlled monomer sequences. Despite the unique potential of the newly developed techniques, tailor-making the microstructure of macromolecules by suggesting the most appropriate polymerization recipe still remains a very challenging task. In the current work, two versatile and powerful tools capable of effectively addressing the aforementioned questions have been proposed ...


Off Axis Compressive Response Of Ice-Templated Ceramics, Rahul Kumar Jujjavarapu Apr 2019

Off Axis Compressive Response Of Ice-Templated Ceramics, Rahul Kumar Jujjavarapu

Mechanical & Aerospace Engineering Theses & Dissertations

The off-axis compressive behavior of ice-templated ceramic was analyzed using experimental results and micro-mechanical model simulation. Ice-templated ceramics is a versatile processing technique used to manufacture anisotropic ceramic foam by exploiting the anisotropic growth characteristics and lamellar morphology. The ice-templating process results in processing-structure-property relationships determined by the microstructure. The processed alumina samples which were later manufactured by water jet machine from the freeze casting were tested under quasi-static off-axis loading conditions and were used to determine the mechanical properties of the material. Digital image correlation (DIC) was used to measure the strain response of ice-templated ceramic under off-axis loading ...


The Study Of Scandate Cathode And Its Characterization Under Various Stages Of Processing, Xiaomeng Zhang Jan 2019

The Study Of Scandate Cathode And Its Characterization Under Various Stages Of Processing, Xiaomeng Zhang

Theses and Dissertations--Chemical and Materials Engineering

Scandate cathode under various processing stages: scandia nano-powder, tungsten scandia mix powder, sintered and impregnated pellets, were characterized with techniques that included electron microscopy, EDS, XPS, and work function measurements. The size and shape uniformity of nano-scale scandia particles changed from round to square and polyhedron during heat treatment. Reduction in size and improvement in size uniformity as heat treating temperature increased were observed. When determining the highest Sc coverage, three assessment methods were used and with their combined results, it was concluded that set VII had the highest Sc at%. In the sintered pellets, it was observed with SEM ...


Liquid Metal-Elastomer Soft Composites With Independently Controllable And Highly Tunable Droplet Size And Volume Loading, Ravi Tutika, Steven Kmiec, A. B. M. Tahidul Haque, Steve W. Martin, Michael D. Bartlett Jan 2019

Liquid Metal-Elastomer Soft Composites With Independently Controllable And Highly Tunable Droplet Size And Volume Loading, Ravi Tutika, Steven Kmiec, A. B. M. Tahidul Haque, Steve W. Martin, Michael D. Bartlett

Materials Science and Engineering Publications

Soft composites are critical for soft and flexible materials in energy harvesting, actuators, and multifunctional devices. One emerging approach to create multifunctional composites is through the incorporation of liquid metal (LM) droplets such as eutectic gallium indium (EGaIn) in highly deformable elastomers. The microstructure of such systems is critical to their performance, however, current materials lack control of particle size at diverse volume loadings. Here, we present a fabrication approach to create liquid metal-elastomer composites with independently controllable and highly tunable droplet size (100 nm ≦ D ≦ 80 μm) and volume loading (0 ≦ φ ≦ 80%). This is achieved through a combination ...


Deformation Correlations And Machine Learning: Microstructural Inference And Crystal Plasticity Predictions, Michail Tzimas Jan 2019

Deformation Correlations And Machine Learning: Microstructural Inference And Crystal Plasticity Predictions, Michail Tzimas

Graduate Theses, Dissertations, and Problem Reports

The present thesis makes a connection between spatially resolved strain correlations and material processing history. Such correlations can be used to infer and classify prior deformation history of a sample at various strain levels with the use of Machine Learning approaches. A simple and concrete example of uniaxially compressed crystalline thin films of various sizes, generated by two-dimensional discrete dislocation plasticity simulations is examined. At the nanoscale, thin films exhibit yield-strength size effects with noisy mechanical responses which create an interesting challenge for the application of Machine Learning techniques. Moreover, this thesis demonstrates the prediction of the average mechanical responses ...


Particle Size-Dependent Microstructure, Hardness And Electrochemical Corrosion Behavior Of Atmospheric Plasma Sprayed Nicrbsi Coatings, Peng Sang, Liang-Yu Chen, Cuihua Zhao, Ze-Xin Wang, Haiyang Wang, Sheng Lu, Dongpo Song, Jia-Huan Xu, Lai-Chang Zhang Jan 2019

Particle Size-Dependent Microstructure, Hardness And Electrochemical Corrosion Behavior Of Atmospheric Plasma Sprayed Nicrbsi Coatings, Peng Sang, Liang-Yu Chen, Cuihua Zhao, Ze-Xin Wang, Haiyang Wang, Sheng Lu, Dongpo Song, Jia-Huan Xu, Lai-Chang Zhang

ECU Publications Post 2013

Particle size is a critical consideration for many powder coating-related industries since it significantly influences the properties of the produced materials. However, the effect of particle size on the characteristics of plasma sprayed NiCrBSi coatings is not well understood. This work investigates the microstructures, hardness and electrochemical corrosion behavior of plasma sprayed NiCrBSi coatings synthesized using different-sized powders. All coatings mainly consist of Ni, N3B, CrB, Cr7C3 and Cr3C2 phases. The coatings produced by small particles (50–75 μm) exhibit lower porosity (2.0 ± 0.8%). Such coatings show a higher fraction (15.5 vol.%) of the amorphous phase and ...


Phase Separation And Enhanced Wear Resistance Of Cu88fe12 Immiscible Coating Prepared By Laser Cladding, Shuzhen Zhao, Shengfeng Zhou, Min Xie, Xiaoqin Dai, Dongchu Chen, Laichang Zhang Jan 2019

Phase Separation And Enhanced Wear Resistance Of Cu88fe12 Immiscible Coating Prepared By Laser Cladding, Shuzhen Zhao, Shengfeng Zhou, Min Xie, Xiaoqin Dai, Dongchu Chen, Laichang Zhang

ECU Publications Post 2013

In order to eliminate the microstructure segregation of Cu–Fe immiscible alloys which characterized with a liquid miscible gap, the Cu88Fe12 (wt.%) immiscible coating was prepared by laser cladding. The phase separation characteristic and wear resistance of the Cu88Fe12 (wt.%) immiscible coating were also investigated. The results show that the size of the milled Cu88Fe12 composite powder is reduced comparing to that of the un-milled powder due to fracturing during mechanical milling. Moreover, the demixing or delamination disappears in the Cu88Fe12 immiscible coating and a large amount of face-centered-cubic (fcc) γ-Fe and body-centered-cubic (bcc) α-Fe particles are dispersed in the ...


Nanoindentation Characterization On Local Plastic Response Of Ti-6al-4v Under High-Load Spherical Indentation, Yan Wen, Lechun Xie, Zhou Wang, Liqiang Wang, Weijie Lu, Laichang Zhang Jan 2019

Nanoindentation Characterization On Local Plastic Response Of Ti-6al-4v Under High-Load Spherical Indentation, Yan Wen, Lechun Xie, Zhou Wang, Liqiang Wang, Weijie Lu, Laichang Zhang

ECU Publications Post 2013

After high-load spherical indentation treatment, the variations of hardness on the plastic zone of Ti-6Al-4V were investigated via nanoindentation method. The hardness within the center of plastic zone was measured by nanoindenter, and the magnitude decreased gradually along the depth, which were caused by the different extent of plastic deformation under the residual imprint. The microstructure of indentation were observed using scanning electron microscope (SEM) before and after surface etching, and the results showed that the microhardness revealed the average hardness of α and β phases of Ti-6Al-4V. The maximum hardness reached 6.438 GPa in the depth of 132 ...


Beta-Type Ti-Nb-Zr-Cr Alloys With Large Plasticity And Significant Strain Hardening, Syed F. Jawed, Chirag D. Rabadia, Y. J. Liu, L. Q. Wang, Y. H. Li, X. H. Zang, Laichang C. Zhang Jan 2019

Beta-Type Ti-Nb-Zr-Cr Alloys With Large Plasticity And Significant Strain Hardening, Syed F. Jawed, Chirag D. Rabadia, Y. J. Liu, L. Q. Wang, Y. H. Li, X. H. Zang, Laichang C. Zhang

ECU Publications Post 2013

A series of Ti-25Nb-8Zr-xCr (x = 0, 2, 4, 6, 8 wt%) alloys were designed based on DV-Xα cluster method and e=a-Δr diagram with an anticipation to obtain high plasticity and significant strain hardening. The designed alloys were produced through cold crucible levitation melting technique in order to effectively investigate their micro-structures and mechanical properties. The addition of Cr significantly enhances the β stability in the microstructures of the Ti-25Nb-8Zr-xCr alloys. Both yield strength and hardness of the studied alloys increase due to the effect of solid-solution strengthening. By contrast, the plasticity, maximum strength and strain hardening rate are influenced ...