Micromechanical Studies of 4n Gold Wire for Fine Pitch Wirebonding

This study focuses towards typical micromechanical properties such as strength, yield point, Young’s Modulus, strain, shapes of fracture end and element analysis, atomic percentage of Ca of 4N gold (Au) wire using microstructures and composition observation, micro-tensile test and depth sensing indentation technique. A series of micro-tensile test were performed with different strain rate values of 10˚-10-4 min-1 on to a 25.4 μm diameter plain gold wire. The nanoindentation with 20 mN maximum load was indented on a near fracture end of a gold wire specimen, for which this test was carried out after the micro-tensile test. The stress-strain curves were used to characterize the 4N purity gold wire. The shapes of fracture end of gold wire after micro tensile test were carried out using Scanning Electron Microscopic (SEM). The finding showed that the mechanical properties of ultra-fine gold wire was in the proportional relationship with the increment of the strain rate value. It is suggested that micromechanical behaviour gave the effect for the wirebonding process in order to characterize the wire loop control and strengthen the wire loop to avoid the wire sweep

An Improved Detection and Classification Technique of Harmonic Signals in Power Distribution by Utilizing Spectrogram

This paper introduces an improved detection and classification technique of harmonic signals in power distribution using time-frequency distribution (TFD) analysis which is spectrogram.  The spectrogram is an appropriate approach to signify signals in jointly time-frequency domain and known as time frequency representation (TFR). The spectral information of signals can be observed and estimated plainly from TFR due to identify the characteristics of the signals. Based on rule-based classifier and the threshold settings that referred to IEEE Standard 1159 2009, the detection and classification of harmonic signals for 100 unique signals consist of various characteristic of harmonics are carried out successfully. The accuracy of proposed method is examined by using MAPE and the result show that the technique provides high accuracy. In addition, spectrogram also gives 100 percent correct classification of harmonic signals. It is proven that the proposed method is accurate, fast and cost efficient for detecting and classifying harmonic signals in distribution system

Effect of annealing, thickness ratio and bend angle on springback of AA6061-T6 with nonuniform thickness section

Non-uniform thickness section section is considered one of the most effective approaches to reduce automotive part weight. Reduction in term of mass and size result in less fuel consumption and greenhouse gases. Thickness is the most significant parameter to formability, therefore forming a section with non-uniform thickness becomes a great challenge. Improper process and incorrect decision may lead to severe defect and one of the main concerns is the springback. This study will focus on springback behaviour of non-uniform thickness AA6061 strip with complex profile using Taguchi Method. Profile projector (PC 3000) is used to measure the spring back and two-line technique is applied to measure angles (after loading) between two lines. Three parameters (i.e. annealing temperature, thickness ratio and bend angle) are studied, and results determine that the most significant parameter is bend angle, followed by thickness ratio, and then by the annealing temperature of the specimen during bending process

Observing the behaviour of reinforced magnesium alloy with carbon-nanotube and lead under 976 m/s projectile impact / M.F. Abdullah ...[et al.]

This paper presents the effects of reinforced magnesium alloy, AZ31B with carbon-nanotube (CNT) and lead (Pb), in terms of ballistic resistance. Magnesium alloys possess high energy absorption capability for impact resistance. However, its capability is limited and needs to be enhanced to resist ballistic impacts. The addition of a reinforcement material within the magnesium alloy, such as CNT or Pb, can improve impact resistance. This study is divided into two ballistic test methods, namely experiment and simulation. The samples involved are the original AZ31B and reinforced AZ31B with CNT and Pb. The projectile type used for ballistic testing was a 5.56 mm FMJ NATO at a velocity of 976 m/s and the thickness of the plate was 25 mm. The aim is to study the ability of the plate against the ballistic resistance. The ballistic experiment utilises a high speed camera, at 100,000 fps, to capture the impact occurring on the plate’s surface. A Cowper-Symonds model is used for the ballistic simulation and indicates the ballistic resistance of the reinforced AZ31B with increments of CNT and Pb. The velocity of the projectile penetrating through the plate was reduced by over 45% compared to the original AZ31B alloy. Reinforcement using CNT and Pb on AZ31B improved the ballistic resistance behaviour and therefore, this material is suitable for use on ballistic panel

Influence of soda lime glass addition on the dielectric properties of CCTO ceramics

The dielectric properties of CCTO ceramics with soda-lime glass addition was investigated. The addition of soda lime glass was varied from 0 - 0.05 wt.% by solid-state reaction. Both XRD patterns of CCTO and CCTO-glass sintered samples showed the formation of CCTO phase with minor peaks of CuO phase, respectively. The phase area analysis of CCTO and CCTOglass proved that the CCTO phase was found to be decreased while the grain boundaries area of CuO + glass was then increased after the addition of soda-lime glass. The dielectric properties of corresponding samples indicated that both εr and tan δ were reduced with glass addition. Thus, it shows that the soda lime glass addition has a significant effect on dielectric properties of CCTO ceramics

AEO7 Surfactant as an Eco-Friendly Corrosion Inhibitor for Carbon Steel in HCl solution

The impact of AEO7 surfactant on the corrosion inhibition of carbon steel (C-steel) in 0.5 M HCl solution at temperatures between 20 °C and 50 °C was elucidated using weight loss and different electrochemical techniques. The kinetics and thermodynamic parameters of the corrosion and inhibition processes were reported. The corrosion inhibition efficiency (IE%) improved as the concentration of AEO7 increased. In addition, a synergistic effect was observed when a concentration of 1 × 10 −3 mol L −1 or higher of potassium iodide (KI) was added to 40 µmol L −1 of the AEO7 inhibitor where the corrosion IE% increased from 87.4% to 99.2%. Also, it was found that the adsorption of AEO7 surfactant on C-steel surface followed the Freundlich isotherm. Furthermore, electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization measurements indicated that AEO7 was physically adsorbed on the steel surface. The surface topography was examined using an optical profilometer, an atomic force microscope (AFM), and a scanning electron-microscope (SEM) coupled with an energy dispersion X-ray (EDX) unit. Quantum chemical calculations based on the density functional theory were performed to understand the relationship between the corrosion IE% and the molecular structure of the AEO7 molecule. © 2019, The Author(s).This publication was supported by Qatar University Internal Grant N° GCC-2017-012. The findings achieved herein are solely the responsibility of the authors. The authors gratefully thank the Center for Advanced Materials at Qatar University and the Chemistry Department at Cairo University for their support. The permanent address of Dr. Mohamed F. Shibl is Chemistry Department, Faculty of Science, Cairo University, Giza 12613, Egypt.Scopu

Characterising Ballistic Limits of Lightweight Laminated-Structure as a Protective Panel for Armoured Vehicle / N.A. Rahman...[et al.]

This study investigates the ballistic performance of aluminium alloy Al7075-T6 and magnesium alloy AZ31B served as the intermediate layer in triple-layered laminated panel using computational analysis. Aluminium and magnesium alloys offer a considerably potential for reducing the weight of an armoured vehicle body due to low densities and high energy absorption capabilities. The poor ballistic performance of these materials can be improved by layering with the high strength steel, Ar500. A commercial explicit finite element code was implemented to develop triple-layered panels impacted by a 7.62 mm armour piercing projectile at velocity range of 900 to 950 m/s. Two models were constructed where aluminium alloy and magnesium alloy served as intermediate layer in the first model and the second model respectively. The ballistic performance of each model in terms of ballistic limit velocity and depth of penetration was evaluated. Considering the 25% existing armour vehicle weight reduction, it was found that magnesium alloy has equivalent ballistic limit to that of aluminium alloy which is at 1020 m/s. At the standard projectile velocity, aluminium stopped the projectile at 24 mm depth and magnesium stopped at 25 mm. Thus, lightweight materials can be suitable combinations for designing lighter armoured vehicle panel without neglecting its ballistic performance