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Full-Text Articles in Engineering

Optimizing The Mechanical Properties Of Partially Yttria Stabilized Zirconia With Alumina Additions, Ramanaganapathy Kandaswamy Dec 2010

Optimizing The Mechanical Properties Of Partially Yttria Stabilized Zirconia With Alumina Additions, Ramanaganapathy Kandaswamy

All Theses

Zirconia is one of the extensively studied solid oxide ceramics with respect to its use in various industrial applications like electrolyte in fuel cells, sensors, refractories and exhaust chamber in automobile industry. It can be found from the literature 1-4 that are contradictory results on the mechanical properties when alumina is added. There are several factors like microstructure, phase composition and method of processing that affects the mechanical properties of the material. The focus of this research is to examine how hardness, tensile strength and other properties varies with alumina content and deduce the optimal amount of alumina that is …


Effect Of Sintering On Microstructure And Properties Of Hydroxyapatite Produced By Different Synthesizing Methods, N Monmaturapoj, C Yatongchai Dec 2010

Effect Of Sintering On Microstructure And Properties Of Hydroxyapatite Produced By Different Synthesizing Methods, N Monmaturapoj, C Yatongchai

Journal of Metals, Materials and Minerals

The aim of this study is to investigate the effect of the sintering schedule on microstructure and properties of hydroxyapatite which is produced by different synthesizing methods. Hence, wet-chemical precipitation and solid-state reaction were performed to prepare nano-sized hydroxyapatite (HA) powders. Powders were then uniaxially pressed and sintered by varying temperatures and times. XRD and SEM were used to identify phases and morphology. Density and porosity of the sintered sample were determined using the Archimedes technique. Flexural strength was measured by a universal testing machine. The results show that density and strength could be improved by increasing the sintering temperature …


Mix Design And Mechanical Properties Of Oil Palm Shell Lightweight Aggregate Concrete: A Review, Hilmi Mahmud Nov 2010

Mix Design And Mechanical Properties Of Oil Palm Shell Lightweight Aggregate Concrete: A Review, Hilmi Mahmud

Hilmi Mahmud

To build environmentally sustainable structures, especially in developing countries, the possibility of using some agricultural wastes and industrial by-products from different industries as construction materials will be highly desirable and has several practical and economic advantages. Oil palm shell (OPS) is a form of agricultural solid waste in the tropical regimes. Research over the last two decades shows that OPS can be used as a lightweight aggregate for producing structural lightweight aggregate concrete. The density of OPS concrete is around 20 - 25% lower than normal weight concrete. Generally, mechanical properties of OPS concrete are slightly lower than the other …


Structural And Mechanical Properties Of Nanostructured Tio2 Thin Films Deposited By Rf Sputtering Oct 2010

Structural And Mechanical Properties Of Nanostructured Tio2 Thin Films Deposited By Rf Sputtering

A.S. Md Abdul Haseeb

This study mainly aims to evaluate the effects of substrate temperatures on the mechanical properties of TiO2 thin films deposited on glass substrates by radio-frequency (RF) magnetron sputtering. All titania films possess anatase structure having a nodular morphology. AES results reveal that Si and Na ions from glass diffuse into TiO2 films at higher substrate temperatures. Micro-scratch and wear tests were conducted to evaluate their mechanical and tribological properties. The adhesion critical loads of TiO2 films deposited at room temperature, 200 and 300°C are found to be 1.51, 1.54 and 1.08N, respectively. Scratch hardness also increases from 11.5 to 13.6GPa …


Doping Dependence Of Electronic And Mechanical Properties Of Gase1−XTeX And Ga1−XInXSe From First Principles, Zs. Rak, S. D. Mahanti, K. C. Mandal, N. C. Fernelius Oct 2010

Doping Dependence Of Electronic And Mechanical Properties Of Gase1−XTeX And Ga1−XInXSe From First Principles, Zs. Rak, S. D. Mahanti, K. C. Mandal, N. C. Fernelius

Faculty Publications

No abstract provided.


Freeze Extrusion Fabrication Of 13-93 Bioactive Glass Scaffolds For Bone Repair, Tieshu Huang, Nikhil D. Doiphode, M. N. Rahaman, Ming-Chuan Leu, B. Sonny Bal, D. E. Day Aug 2010

Freeze Extrusion Fabrication Of 13-93 Bioactive Glass Scaffolds For Bone Repair, Tieshu Huang, Nikhil D. Doiphode, M. N. Rahaman, Ming-Chuan Leu, B. Sonny Bal, D. E. Day

Materials Science and Engineering Faculty Research & Creative Works

There is an increasing demand for synthetic scaffolds with the requisite biocompatibility, internal architecture, and mechanical properties for the bone repair and regeneration. In this work, scaffolds of a silicate bioactive glass (13-93) were prepared by a freeze extrusion fabrication (FEF) method and evaluated in vitro for potential applications in bone repair and regeneration. The process parameters for FEF production of scaffolds with the requisite microstructural characteristics, as well as the mechanical and cell culture response of the scaffolds were evaluated. After binder burnout and sintering (60 min at 700°C), the scaffolds consisted of a dense glass network with interpenetrating …


Performance Of Nevada’S Aggregates In Alkali-Aggregate Reactivity Of Portland Cement Concrete, Mohammad Shahidul Islam May 2010

Performance Of Nevada’S Aggregates In Alkali-Aggregate Reactivity Of Portland Cement Concrete, Mohammad Shahidul Islam

UNLV Theses, Dissertations, Professional Papers, and Capstones

Alkali-aggregate reaction (AAR) is a form of distress that occurs in concrete and results in serviceability problems, cracks, spalling, and other deterioration mechanisms. There are two categories of AAR, namely, alkali-silica reaction (ASR) and alkali-carbonate reaction (ACR). Alkali-silica reaction is one of the most recognized deleterious phenomena in concrete, and has been a major concern since its discovery in the 1940s. The reaction which occurs between reactive silica or silicates present in some aggregates and alkalis of Portland cement produces an alkali-silica gel that expands in the presence of moisture resulting in concrete cracks. ACR is also a chemical reaction …


Photo-Cross-Linked Pdmsstar-Peg Hydrogels: Synthesis, Characterization, And Potential Application For Tissue Engineering Scaffolds, Yaping Hou, Cody Schoener, Katherine Regan, Dany Munoz Pinto, Mariah Hahn, Melissa Grunlan Mar 2010

Photo-Cross-Linked Pdmsstar-Peg Hydrogels: Synthesis, Characterization, And Potential Application For Tissue Engineering Scaffolds, Yaping Hou, Cody Schoener, Katherine Regan, Dany Munoz Pinto, Mariah Hahn, Melissa Grunlan

Dany J. Munoz Pinto

Inorganic−organic hydrogels with tunable chemical and physical properties were prepared from methacrylated star polydimethylsiloxane (PDMSstar-MA) and diacrylated poly(ethylene glycol) (PEG-DA) for use as tissue engineering scaffolds. A total of 18 compositionally unique hydrogels were prepared by photo-cross-linking, varying weight ratios of PEG-DA and PDMSstar-MA of different molecular weights (Mn): PEG-DA (Mn = 3.4k and 6k g/mol) and PDMSstar-MA (Mn = 1.8k, 5k, and 7k g/mol). Introduction of PDMSstar-MA caused formation of discrete PDMS-enriched microparticles dispersed within the PEG matrix. The swelling ratio, mechanical properties in tension and compression, nonspecific protein adhesion, controlled introduction of bioactivity, and cytotoxicity of hydrogels were …


Effect Of Aggregate Size And Proportion On Strength Properties Of Palm Kernel Shell Concrete, Hilmi Mahmud Jan 2010

Effect Of Aggregate Size And Proportion On Strength Properties Of Palm Kernel Shell Concrete, Hilmi Mahmud

Hilmi Mahmud

This paper presents information on the physical and mechanical properties of different sizes of palm kernel shells (PKS) used here as lightweight aggregates (LWA) and their influence on mechanical properties of palm kernel shell concrete (PKSC). Silica fume and fly ash were used as cementitious materials and all mixes had 1% superplasticizer on cement weight. It has been found that PKS consists of about 65 to 70% of medium size particles in the range of 5 to 10 mm. The other two sizes, namely, small (0-5 mm) and large (10-15 mm) sizes were found to influence the mechanical properties of …


Development Of Lightweight Concrete Using Industrial Waste Material, Palm Kernel Shell As Lightweight Aggregate And Its Properties, Hilmi Mahmud Jan 2010

Development Of Lightweight Concrete Using Industrial Waste Material, Palm Kernel Shell As Lightweight Aggregate And Its Properties, Hilmi Mahmud

Hilmi Mahmud

Agricultural industrial wastes produced after extracting palm oil from palm fruits known as palm kernel shell (PKS) are available in large quantities in Indonesia, Malaysia, Nigeria and other tropical countries. Malaysia is the second largest palm oil producing country in the world. This paper reports the results of an investigation conducted to utilize the PKS as lightweight aggregate to produce grade30 concrete with density of about 1850kg/m 3. The properties of both PKS and crushed granite aggregates were compared. The concrete produced using PKS referred to here after as palm kernel shell concrete (PKSC) and its properties were compared with …


Effect Of Aggregate Size And Proportion On Strength Properties Of Palm Kernel Shell Concrete, Zamin Jumaat Jan 2010

Effect Of Aggregate Size And Proportion On Strength Properties Of Palm Kernel Shell Concrete, Zamin Jumaat

Zamin Jumaat

This paper presents information on the physical and mechanical properties of different sizes of palm kernel shells (PKS) used here as lightweight aggregates (LWA) and their influence on mechanical properties of palm kernel shell concrete (PKSC). Silica fume and fly ash were used as cementitious materials and all mixes had 1% superplasticizer on cement weight. It has been found that PKS consists of about 65 to 70% of medium size particles in the range of 5 to 10 mm. The other two sizes, namely, small (0-5 mm) and large (10-15 mm) sizes were found to influence the mechanical properties of …


Designing A Whey Protein Based Material As A Scaffold For Bone Regeneration, Mia Dvora Jan 2010

Designing A Whey Protein Based Material As A Scaffold For Bone Regeneration, Mia Dvora

LSU Doctoral Dissertations

A novel gel material was designed and optimized for use as a bone tissue regeneration scaffold. Whey protein isolate (WPI), the primary component of the material, underwent considerable testing for conformity to a set of known material characteristics required for application in bone regeneration. WPI gels of different compositions were fabricated by thermally inducing gelation of high-concentration protein suspensions, and characterized for compressive strength and modulus, hydration swelling and drying properties, mechanical behavior change due to polysaccharide additives, and intrinsic pore network structure. The gels were also tested for their compatibility with MC3T3-E1 cells, and interactions such as cell adhesion, …


Comparison Of Mechanical And Bond Properties Of Oil Palm Kernel Shell Concrete With Normal Weight Concrete, Zamin Jumaat Dec 2009

Comparison Of Mechanical And Bond Properties Of Oil Palm Kernel Shell Concrete With Normal Weight Concrete, Zamin Jumaat

Zamin Jumaat

The comparison of the fresh, mechanical and bond properties of grade 30 lightweight concrete, namely oil palm kernel shell concrete (OPKSC) with normal weight concrete (NWC) of similar strength is presented in this paper. Oil palm kernel shell (OPKS), an industrial waste has been used as lightweight aggregates (LWA) in the OPKSC. In addition, mineral admixtures, 10% of silica fume and 5% fly ash have been used. The OPKSC produced a density reduction of about 20% compared to NWC. The addition of silica fume enhanced the compressive strength and thus OPKSC produced 28-day compressive strength up to 37 MPa. The …