Interfacial reaction between SAC305 and SAC405 lead-free solders and electroless nickel/immersion silver (ENImAg) surface finish

The different surface finish and solder size on printed circuit board strongly affect the formation of intermetallic compounds (IMCs) and solder joint reliability. Among of various surface finish in the electronic industry, electroless nickel/immersion gold is the most popular at the moment. However, because their black pad issues, electroless nickel/immersion silver (ENImAg) was developed as an alternative surface finish. Therefore, the effect on an interfacial reaction between lead-free solder and ENImAg surface finish using different solder ball size (Ø300μm, Ø500μm and Ø700μm) was investigated. All samples were subjected to an aging process with different aging times. The characterizations of IMC formation were examined by image analyzer, scanning electron microscopy and energy dispersive x-ray. The results showed that ENImAg finish was free from the black pad nickel. Subsequently, the solder ball size has a significant effect on the IMC formation and fracture surface of as-reflowed and aged solder joint. The IMC thickness of larger solder balls was found to be thicker (1.74 μm) than smaller solder balls (1.32 μm) during soldering. In contrast to aged solder joints, the smaller solder ball produced thicker (3.51 μm) IMC compared to bigger solder balls (2.47 μm). Furthermore, the fracture surface of smaller solder ball size showed ductile mode for both reflowed and aged solder joints. In addition, the solder joint on ENImAg surface finish displayed a thinner layer and smaller grain sizes compared to solder joint on bare copper

Design and Development of MY 2nd EYE for Visually Impaired Person

This paper discussed on design and development of electronic device by using warning system for visually impaired person usage which is called ‘MY 2 nd EYE’. This electronic device is designed to support and help the visually impaired person around this world to have their own confident in order to travel from one place to another place. This project is about developing of warning system by using a vibration motor as a warning device via microcontroller that received input from distance measurement sensor when detecting obstacle. The vibration motor is a best solution to warn the blind person because it uses touch sense of human when the system is run. In this system, there are four pieces of vibration motor are mounted to the gloves at different locations. Each location will have its own function that show different direction such as front, left, right and down. In this project, the effectiveness of the system gives command the direction of obstacle existence is very important and have been confirmed through simulation and experiment

Moving Control of Quadruped Hopping Robot Using Adaptive CPG Networks

This paper describes the moving control using the adaptive Central Pattern Generators (CPGs) including motor dynamic models for our developed quadruped hopping robot. The CPGs of each leg is interconnected with each other and by setting their coupling parameters can act as the flexible oscillators of each leg and adjust the hopping height of each leg to require stable hopping motion. The formation of the CPG networks are suitable not only to generate the continuous jumping motion but also can generate the moving motion in twodimensional, respectively. We also propose the reference height control system which including the maximum hopping height detector and Proportional Integral (PI)controller to achieve the reference jumping height. By using the proposed method, the hopping height of each leg can be control independently in order to make the posture of robot’s body incline ahead and move forward. We create MATLAB/Simulink model to conduct various types of experiments and confirmed the effectiveness of our proposed CPG model including the reference height control system to generate the stable moving performance while jumping continuously

Study Of The Relationship Between Delta Delay And Adjacent Parallel Wire Length In 45 Nanometer Process Technology

Hierarchical design spans the complete framework of a design flow from Register Transfer Level (RTL), synthesis, place and route, timing closure and various other analyses before sign-off. Finer geometries and increasing interconnect density however have resulted signal integrity becoming the key issue for Deep Sub-Micron design. Post silicon bug due to noise and signal integrity can be prevented and fixed at early stage of the IC design cycle. The purpose of this research is to establish a preventive measurement for adjacent wire that can travel in parallel for 45nm technology. The intention is to ensure that a complex design can be delivered to the market with accurate, fast and trusted analysis and provide sign-off solution. Main approach is to conduct the relationship study between delta delay and adjacent parallel wire in 45 nanometer (nm) process technology and provide a preventive measurement to limit the adjacent wire can travel in parallel. The design is explored thoroughly to study the relationship between delay noise and adjacent parallel wire. The correlation is translated into an equation to estimate the delay noise produced with a certain length of adjacent parallel wire

Leadership style in knowledge-based culture: The competitive advantage approach

In nowadays economy, knowledge becoming the primary bases of core competency and key to superior performance. Several reasons are advanced for the implementation of knowledge management (KM) within companies. These includes of the widespread digitalisation of business environments; the rise of time-based competition that require firms to learn as much as possible in very short periods; the globalization of operations; and the high incidence of mergers and takeovers. Thus, for these reasons, it is crucial for a company to explore any factors that can enhance the knowledge-based organization. The proper way in managing the knowledge will lead to firm’s competitive advantage achievement. In this paper, the leadership styles as important factors in enhance the practices of knowledge-based culture will be the main focused. Specifically, this paper is to address three main objectives. First objective is to discuss the important of leadership styles in association to organizational learning culture, the most excellent principal in order to manage and value knowledge. Secondly, this paper will explain the important of leadership styles in firm’s competitive advantage achievement. And lastly, this paper will further discuss the important of leadership role in inter-firm settings and it relationship to competitive advantage

Elevated Highways and its Lost Spaces: A Review of Kuala Lumpur’s seldom seen

The development of the urban highway in and around the city has created vast quantities of left over spaces that seldom integrated into formal planning and design. Vague on purpose, the interstitial spaces formed from these concrete “rivers” are referred as lost spaces. This paper aims to explore the urban interstices and investigate its possible usage. Site observation and photographic recordings of a case study were employed. The site characteristics were recorded in which findings suggested that the interstitial spaces have the potential to be planned and designed to cater adjacent community needs and usage

Cross-country comparison of engagement in apprenticeships: A conceptual analysis of incentives for individuals and firms

Purpose: A fundamental assumption of the apprenticeship model is that there are benefits to both employers and individual learners. This paper offers a broad conceptual interrogation of an inherent assumption in the apprenticeship model, in that it provides incentives for participation to both individual learners and employers. Approach: This study combines the analysis of literature and available data and draws upon apprenticeship models in ten nations: Australia, Brazil, Denmark, Egypt, England, Finland, Germany, India, Malaysia and South Africa. Findings: For individuals, incentives to undertake apprenticeship may be linked to the process and outcomes of that learning, such as the appeal of learning through doing; the opportunities for occupational socialization; the possibility of progression to employment or to additional education; and learning while earning. The analysis of incentives for employers shows a range of reasons related to their short-term interests and the needs of the production processes, technologies, and associated skills; longer-term benefits for the company’s staffing strategy; and the opportunity to make a contribution to the wider education and economic systems. Despite all the potential incentives, many firms consider apprenticeships too costly, risky, and complex to justify the investment. However, when firms are making decisions under the umbrella of chambers or associations, they are more likely to coordinate their skills investment strategies around collectively beneficial outcomes. Conclusion: The links to the labour market and specifically to employers are a key challenge for sustaining apprenticeship systems, as well as for the task of researching them. As such, policy maker (and researcher) engagement with apprenticeship should account for the capacity and commitment of employers. Another key challenge for apprenticeship is related to the relative attractiveness of this pathway within E&T and labour market system for individuals. What is clear from this study is that the development of a strong apprenticeship system requires the buy-in of both employers and individual learners, and as such the necessity to identify and effectively implement incentives cannot be underestimated. Governments can play a key role in realizing the potential incentives for both employers and learners, thereby yielding benefits of all parties engaged in apprenticeships

Numerical Investigation Of Stagnation Point Flow Over a Stretching Sheet With Convective Boundary Conditions

In this study, the mathematical modeling for stagnation point flow over a stretching surface with convective boundary conditions is considered. The transformed boundary layer equations are solved numerically using the shooting method. Numerical solutions are obtained for the skin friction coefficient, the surface temperature as well as the velocity profiles. The features of the flow and heat transfer characteristics for various values of the Prandtl number, stretching parameter and conjugate parameter are analyzed and discussed

Exploratory Study on Navigation System for Visually Impaired Person

Direction is arguably the most pressing concern for visually impaired person. Nevertheless, we lack a convenient navigation system to guide a visually impaired person using point to point direction to reach desired destination independently while walking on tactile paving. Accessibility of this navigation system must be convenient and simple for visually impaired people. In order to provide an efficient and user friendly assistive tool, it is proposed to design and develop a navigation system using Radio Frequency Identification (RFID) to guide the visually impaired walking on tactile paving. Path planning algorithm will be implemented in this project to give the shortest path and direction as a navigation guide for visually impaired people. This project will directly contribute to society by making available a convenient navigation system for visually impaired people for a better lifestyle

Control of Maximum Power Point Tracking for Stand-Alone Photovoltaic System Using Voltage Comparison Technique

This paper proposed the other method to control of maximum power point tracker for stand- alone photovoltaic system using closed-loop voltage mode control algorithm. Approach: The PV module was modeled based on the parameters obtained from a commercial PV data sheet while voltage mode control was modeled using simulink block model. A DC-DC boost converter was chosen to regulate the DC voltage from the PV module. The voltage mode control maximum power point tracking model was simulated under a constant and a variable change of solar irradiance and temperature. The perturb and observe maximum power point tracker model was developed and compared with this proposed method in order to validate the performance of output results. Results: Results showed that the voltage mode control maximum power point tracking model yields the similar performance as produced by the photovoltaic system controlled by perturb and observe maximum power point tracking algorithm simulation in terms of the voltage, current and power generated under the changing irradiant and temperature condition. Conclusion/Recommendations: The voltage mode control technique is possible to be implemented which yields the similar performance as the results from conventional MPPT method