Engineering Commons^™

An Investigation And Understanding Of The Mechanical Response Of Palmyrah Timber, Hatim Sobier, Craig Menzemer, Tirumalai Srivatsan

Craig Menzemer

The Palmyrah tree flourishes in tropical areas around South East Asia, and particularly in Sri Lanka. Palmyrah is an important economic resource for the region, and has found use in structural applications for both residential dwellings and commercial buildings. While there is a great deal of local field experience with Palmyrah, the mechanical properties have not been well characterized or understood. In an effort to assist engineers with the design and efficient use of the timber, a study was undertaken to evaluate the mechanical response of Palmyrah and develop estimates of design allowable properties. Properties evaluated include static bending strength, …

Numerical Analysis Of Free-Edge Effect On Size-Influenced Mechanical Properties Of Single-Layer Triaxially Braided Composites, Chao Zhang, Wieslaw Binienda

Wieslaw K. Binienda

The mechanical properties of triaxially braided composites under transverse loads are found to be size-dependent, due to the presence of free-edge effect. Numerical studies of the mechanical behaviors of straight-sided coupon specimens and an infinitely large plate under both axial and transverse tension loads were conducted using a meso-scale finite element model. The numerical model correlates well with experimental results, successfully capturing the free-edge warping phenomena under transverse tension. Free-edge effect is observed as out-of-plane warping, and it can be correlated to the premature damage initiation in the affected area. The numerical results characterize the impact of free-edge effects on …

Mechanical Properties Of Intermetallic Compounds In Electrodeposited Multilayered Thin Film At Small Scale By Nanoindentation

Faculty of Engineering University of Malaya

Mechanical properties of intermetallic compounds (IMCs) which were formed in electrodeposited Cu/Sn and Cu/Ni/Sn multilayered thin film have been investigated. The layers of Cu, Sn and Ni were formed by electrodeposition technique using copper pyrophosphate, tin methanesulfonic and nickel Watts baths, respectively. After synthesis, samples were subjected to high temperature aging at 150 degrees C for 168 h. Two different types of intermetallics Cu3Sn and Cu6Sn5 were formed in Cu/Sn. After adding ultra-thin layer of Ni (70 nm) in between Cu and Sn layers, (Cu, Ni)(6)Sn-5 was formed after aging at similar condition to that of Cu/Sn. Tin whisker growth …

Joints Properties Of One Side Welded Of Ship Materials With Variation Of Angle Groove, Innovative Research Publications Irp India, Yustiasih Purwaningrum, Triyono No, Tri Syarifuddin, Isharyadi Di

Innovative Research Publications IRP India

Indonesian National Transportation Safety Commission based on data from the period 2003-2008 and The Study for the Maritime Traffic Safety System Development Plan states that 21% of the cause of the accident was the failure of Indonesian ship in the structure of the ship (hull structure). This study aimed to investigate the effect of variations in the angle groove of one side welding. Material used is low carbon steel LR grade A in a thickness 12 mm were welded using GMAW (Gas Metal Arc Welding) with a angle groove 20°, 40° and 60°. The physical properties examined with an optical …

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

Krishna C. Mandal

No abstract provided.

Modeling Of Electromechanical Behavior Of Woven Sic/Sic Composites, Xhenhai Xia, Thanyawalai Sujidkul, Jianbing Niu, Craig Smith, Gregory Morscher

Dr. Gregory N. Morscher

A coupled electro-mechanical model was developed to predict the mechanical behavior of woven SiC/SiC ceramic matrix composites and electrical resistance response to mechanical damages in the composites. The matrix is explicitly included in the model such that the matrix cracking and fiber break can be linked to the electrical resistance change during loading. The results show that the electrical resistance increases linearly with an increase of matrix crack density and the number of fiber breaks. The predictions are compared to the experimental results on 2D woven SiC/SiC ceramic composites. With proper materials parameters input, the models can accurately predict the …

Sintering Behaviour Of Natural Porous Hydroxyapatite Derived From Bovine Bone

Faculty of Engineering University of Malaya

The aim of this research is to study the properties of natural porous hydroxyapatite developed from bovine bone through a sintering process. Bovine bone samples were prepared and sintered in an air atmosphere at different temperatures ranging from 600 degrees C to 1000 degrees C. The sintered bodies were characterized to determine the phases present, bulk density, Ca/P ratio and Vickers hardness. In addition, the microstructural evolution of the sintered porous bodies was also examined. The results revealed that the thermal stability of the HA matrix was not disrupted and that all of the sintered bodies exhibited phase pure HA. …

Sintering Behaviour Of Natural Porous Hydroxyapatite Derived From Bovine Bone

Faculty of Engineering University of Malaya

The aim of this research is to study the properties of natural porous hydroxyapatite developed from bovine bone through a sintering process. Bovine bone samples were prepared and sintered in an air atmosphere at different temperatures ranging from 600 degrees C to 1000 degrees C. The sintered bodies were characterized to determine the phases present, bulk density, Ca/P ratio and Vickers hardness. In addition, the microstructural evolution of the sintered porous bodies was also examined. The results revealed that the thermal stability of the HA matrix was not disrupted and that all of the sintered bodies exhibited phase pure HA. …

Alternative Methods To Determine The Elastoplastic Properties Of Sintered Hydroxyapatite From Nanoindentation Testing

Faculty of Engineering University of Malaya

This study introduces alternative methods to determine the elastoplastic properties of bovine-derived Hydroxyapatite (HA) porous bone graft through a set of nanoindentation tests with a Berkovich indenter. Generally, experimental data obtained from nanoindentation tests are force displacement, hardness and elastic modulus. However, to determine plastic properties such as strength coefficient and work hardening exponent of bovine HA, analytical or inverse finite element models are required. In this paper, the effect of sintering temperature on these properties of HA is studied for the range of 1000-1400 degrees C. The direct and inverse Finite Element (FE) simulation models for nanoindentation tests were …

Enhancement Of The Mechanical Properties Of Lightweight Oil Palm Shell Concrete Using Rice Husk Ash And Manufactured Sand

Faculty of Engineering University of Malaya

This study explores the use of rice husk ash (RHA) and manufactured sand (M-sand) as replacements for cement and fine aggregate, respectively, in lightweight oil palm shell concrete (OPSC). In the first stage of this study, the effect of various cement replacement levels, with RHA (5%, 10%, 15%, and 20%) and 100% sand replacement with M-sand and quarry dust (QD), on the compressive strength of OPSC was investigated. The results showed that the highest compressive strength of OPSC of about 51.49 MPa was achieved with the use of 15% RHA and M-sand. In the second stage of the work, the …

Properties Of Zn-Bi Composite Coatings Prepared By Ionic Co-Discharge Deposition

Faculty of Engineering University of Malaya

Zn-Bi composite was synthesized by ionic co-discharge deposition and its properties were investigated. The results show that the Zn-Bi composite with the incorporation of Bi has a finer grain size than the pure Zn coating and improves the mechanical properties. The microhardness is increased by approximately two times simply by adding a small amount of Bi electrolyte into a Zn bath solution. A lower volume loss of the Zn-Bi composite coating compared with the pure Zn coating also indicates that the Zn-Bi coating has a better wear resistance. Link to Full-Text Articles : http://www.sciencedirect.com/science/article/pii/S1003632615635968

Conductive Concrete Overlay For Bridge Deck Deicing: Mixture Proportioning, Optimization, And Properties, Sherif Yehia, Christopher Tuan

Christopher Y. Tuan

Bridge pavement surfaces are prone to ice accumulation, making winter travel hazardous. Current practice is to use road salt and deicing chemicals, that cause damage to concrete and corrosion of reinforcing steel. A thin conductive concrete overlay can generate enough heat to prevent ice formation on a bridge deck. Conductive concrete is a cementitious admixture containing electrically conductive components that attain stable and high electrical conductivity. Due to the electrical resistance and impedance in conductive concrete, heat is generated when connected to a power source, and can be used for deicing or anti-icing. Conductive concrete is a relatively new material …

Effects Of Heat Treatment On Oil Palm Shell Coarse Aggregates For High Strength Lightweight Concrete, Hilmi Mahmud

Hilmi Mahmud

In this study, the effects of heat treatment on oil palm shell (OPS) coarse aggregates are evaluated for high strength lightweight concrete (HSLWC). OPS coarse aggregates are subjected to heat treatment at two temperature settings (60 and 150. °C) and duration of heat treatment (0.5 and 1. h). The reduction in density is found to be within the range of HSLWC when heat-treated OPS aggregates are added into the oil palm shell concrete (OPSC). The results reveal that workability of the OPSC increases with an increase in temperature and duration of heat treatment of the OPS aggregates. It is found …

Engineering Properties Of Oil Palm Shell Lightweight Concrete Containing Fly Ash, Hilmi Mahmud

Hilmi Mahmud

The effect of cement replacement with type F fly ash at 0%, 10%, 30% and 50% on some engineering properties of an oil palm shell (OPS) high strength lightweight concrete was investigated. The properties studied include workability, density, compressive strength, splitting tensile strength, flexural strength, water absorption and drying shrinkage. The effect of initial water curing periods of 2, 4 and 6. days after demoulding and air drying environment on the 28-day compressive strength was also investigated. The test results showed that even with 50% substitution of cement with fly ash, a low cost grade 30 OPS lightweight concrete can …

Electrodeposition Of Lead-Free Solder Alloys

A.S. Md Abdul Haseeb

Purpose - The purpose of this paper is to enhance the understanding on the electrodeposition of various lead (Pb)-free solder alloys, so that new studies can be carried out to solve processing issues. Design/methodology/approach - The paper reviews the available reports on the electrodeposition of tin (Sn)-based solder systems and identifies the challenges in this area. Findings - Compositional control remains a major challenge in this area, where the achievement of desired composition for binary and ternary alloys is subjected to uncertainties. The use of chelating agents in the bath and optimization of parameters can assist the achievement of near-desired …

Failure Analysis Of Superheater Tube Supports Of The Primary Reformer In A Fertilizer Factory

A.S. Md Abdul Haseeb

Eutectic Sn-Bi alloy is gaining considerable attention in the electronic packaging industry because of its favorable properties such as low melting temperature, good wettability, and good mechanical properties. Miniaturization of electronic devices requires small solder bumps, a few tens of micrometers in diameter. Electrodeposition is a reliable technique for the deposition of small volume of solder. This work focuses on the formation of eutectic Sn-Bi solder by reflowing a metal stack containing sequentially electrodeposited Sn and Bi layers. The effects of layering sequence on the composition and microstructure of the resulting alloy is investigated. Irrespective of the layering sequence, a …

Effect Of Applied Uniaxial Stress On Rate And Mechanical Effects Of Cross-Linking In Tissue-Derived Biomaterials, Debbie Chachra, Paul Gratzer, Christopher Pereira, J. Lee

Debbie Chachra

Conformational changes in collagen fibrils, and indeed the triple helix, can be produced by application of mechanical stress or strain. We have demonstrated that the rate of cross-linking in glutaraldehyde and epoxide homobifunctional reagents can be modulated by uniaxial stress (strain). Two poly(glycidyl ether) epoxides were used: Denacol^® EX-810 (a small bifunctional reagent), and Denacol EX-512 (a large polyfunctional reagent). To prevent any possible effect from being masked by saturation of cross-linking sites, bovine pericardium was cross-linked to such an extent that the increase in collagen denaturation temperature, T_d, was one-half of the maximal rise achievable with …

Lumbar Vertebral Density And Mechanical Properties In Aged Ovariectomized Rats Treated With Estrogen And Norethindrone Or Norgestimate, Carla Vanin, Neil Maclusky, Debbie Chachra, Mehran Kasra, Marc Grynpas, Robert Casper

Debbie Chachra

OBJECTIVE: This study was designed to investigate the effects of estrogen alone or combined with two different progestins, norethindrone or norgestimate, on bone density and compressive mechanical properties in an aged rat model.

STUDY DESIGN: Twenty 11-month-old female Sprague-Dawley rats were sham operated (intact control) and 80 wee overiectomized. Three groups of 20 ovariectomized rats were implanted with Silastic silicon rubber (Dow Corning, Midland, Mich.) capsules containing 5% estradiol (wt/wt) in cholesterol. All rats in the intact control (group 1) and the ovariectomized (group 2) and the first of the overiectomized plus estrogen (group 3) groups were injected subcutaneously daily …

The Effect Of Different Hormone Replacement Therapy Regimens On The Mechanical Properties Of Rat Vertebrae, Debbie Chachra, M. Kasra, Carla Vanin, N. Maclusky, R. Casper, Marc Grynpas

Debbie Chachra

The purpose of this study was to examine the effects of estrogen replacement, in concert with three different progestin regimens, on the mechanical properties of rat lumbar vertebrae. Ninety-two Sprague-Dawley rats (11 months old) were divided into six groups for treatment. The first group was an intact control, the second group (OVX) was ovariectomized only, and the third group (estrogen-only) was ovariectomized and received continuous estrogen through a 17-estradiol implant. The remaining groups were ovariectomized and received estrogen and progestin (norethindrone, NET) therapy; 3 g of NET was injected daily (estrogen plus continuous NET), or 6 g of NET was …

A New Tool To Assess The Mechanical Properties Of Bone Due To Collagen Degradation, C. Wynnyckyj, S. Omelon, K. Savage, M. Damani, Debbie Chachra, Marc Grynpas

Debbie Chachra

Current clinical tools for evaluating fracture risk focus only on the mineral phase of bone. However, changes in the collagen matrix may affect bone mechanical properties, increasing fracture risk while remaining undetected by conventional screening methods such as dual energy x-ray absorptiometry (DXA) and quantitative ultrasound (QUS). The mechanical response tissue analyzer (MRTA) is a non-invasive, radiation-free potential clinical tool for evaluating fracture risk. The objectives of this study were two-fold: to investigate the ability of the MRTA to detect changes in mechanical properties of bone as a result of treatment with 1 M potassium hydroxide (KOH) and to evaluate …

Lightweight Aggregate Concrete Fiber Reinforcement - A Review, Hilmi Mahmud

Hilmi Mahmud

The higher brittleness and lower mechanical properties of lightweight aggregate concrete (LWAC) compared to normal weight concrete (NWC) at the same compressive strength has prevented it from being widely used in the construction industry despite its many advantages. Studies have shown that the use of fibers in LWAC is an appropriate solution to resolve such problems. This paper reviews the influence of the addition of fibers on the properties of different types of LWAC. These properties include the workability, compressive strength, stress-strain behavior, tensile strength, modulus of elasticity, and compressive and flexural toughness. Generally, the inclusion of fibers in LWAC, …

A New Method Of Producing High Strength Oil Palm Shell Lightweight Concrete, Hilmi Mahmud

Hilmi Mahmud

This paper presents a new method to produce high strength lightweight aggregate concrete (HSLWAC) using an agricultural solid waste, namely oil palm shell (OPS). This method is based on crushing large old OPS. Crushed OPS are hard and have a strong physical bond with hydrated cement paste. The 28 and 56. days compressive strength achieved in this study were about 53 and 56. MPa, respectively. Furthermore, it was observed that it was possible to produce grade 30 OPS concrete without the addition of any cementitious materials. Compared to previous studies, significantly lower cement content was used to produce this grade …

Shear Behaviour Of Reinforced Palm Kernel Shell Concrete Beams, Hilmi Mahmud

Hilmi Mahmud

The shear behaviour of palm kernel shell concrete (PKSC) beams prepared using palm kernel shell (PKS) as lightweight aggregate (LWA) is reported here. The shear strength of grade 30 PKSC with a density of 1850 kg/m(3) was found 24% higher than the corresponding normal weight concrete (NWC). Good aggregate interlock in PKSC was evident as it produced shorter jagged cracks compared to longer plain cracks of NWC. Further, PKSC was able to produce twice as many flexural and shear cracks compared to NWC. Tension stiffening between the tensile cracks of PKSC enhanced flexural rigidity and dowel action. The non-linear numerical …

Enhancement And Prediction Of Modulus Of Elasticity Of Palm Kernel Shell Concrete, Hilmi Mahmud

Hilmi Mahmud

This paper presents results of an investigation conducted to enhance and predict the modulus of elasticity (MOE) of palm kernel shell concrete (PKSC). Scanning electron microscopic (SEM) analysis on palm kernel shell (PKS) was conducted. Further, the effect of varying sand and PKS contents and mineral admixtures (silica fume and fly ash) on compressive strength and MOE was investigated. The variables include water-to-binder (w/. b) and sand-to-cement (s/. c) ratios. Nine concrete mixes were prepared, and tests on static and dynamic moduli of elasticity and compressive strength were conducted. The SEM result showed presence of large number of micro-pores on …

High-Strength Rice Husk Ash Concrete Incorporating Quarry Dust As A Partial Substitute For Sand, Hilmi Mahmud

Hilmi Mahmud

Quarry dust is a by-product from the granite crushing process in quarrying activities. This paper presents the findings from experimental work undertaken to evaluate the suitability of quarry dust as a partial substitute for sand in high-strength concrete (HSC) containing rice husk ash (RHA). Two grades of HSC mixes, to achieve 60 MPa and 70 MPa at 28 days, were designed with and without the incorporation of RHA. Quarry dust was then used in the mixes containing RHA as a partial substitute for sand, in quantities ranging from 10% to 40%. The slump of the fresh concrete and the compressive …

Understanding The Effects Of Addition Of Copper Nanoparticles To Sn-3.5 Ag Solder

A.S. Md Abdul Haseeb

Purpose - The purpose of this paper is to focus on the fabrication of SAC nanocomposites solder and discuss the effects of nanoCu addition on the structure and properties of resulted nanocomposite solder. Design/methodology/ approach - Ball milling is a nonequilibrium processing technique for producing composite metal particles with submicron homogeneity by the repeated cold welding and fracture of powder particles. This method is believed to offer good processablity, precise control over the solder composition, and produce more homogeneous mixture. Findings - It is found that the melting temperature, the wetting behaviour, and hardness are improved when the Cu nanoparticles …

A New Method Of Producing High Strength Oil Palm Shell Lightweight Concrete, Zamin Jumaat

Zamin Jumaat

This paper presents a new method to produce high strength lightweight aggregate concrete (HSLWAC) using an agricultural solid waste, namely oil palm shell (OPS). This method is based on crushing large old OPS. Crushed OPS are hard and have a strong physical bond with hydrated cement paste. The 28 and 56 days compressive strength achieved in this study were about 53 and 56 MPa, respectively. Furthermore, it was observed that it was possible to produce grade 30 OPS concrete without the addition of any cementitious materials. Compared to previous studies, significantly lower cement content was used to produce this grade …

Influence Of Co2 Laser Radiation On The Mechanical Properties Of Portland Cement Pastes, Maria Del Rosario Moreno-Virgen, Juan José Soto-Bernal, José A. Ortíz-Lozano, Adrian Bonilla-Petriciolet, José Vega-Duran, Rosario González-Mota, José Pineda-Piñon

Adrian Bonilla-Petriciolet

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

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 …