Eng Hwa Yap

Dynamics of a piezoelectric beam subjected to water droplet impact with water layer formed on the surface

Rain impact energy harvesting using piezoelectric energy harvester has gained much attention recently. However, previous works have only considered the effect of single water droplet. In the case of raindrop, water would accumulate on the surface of the energy harvester and form a shallow water layer. This article models the dynamics of a piezoelectric beam, served as a raindrop energy harvester, subjected to water droplet impact with water layer formed on the surface. The impact of water droplet on the tip of the energy harvester is modelled as an impulsive force, and the water layer on the surface of the energy harvester is modelled as an added mass to the energy harvester. An attempt to model the force generated by the water ripple as a distributed load on the piezoelectric beam is presented. Numerical studies have been conducted based upon the proposed mathematical model verified by experimental results. The results showed that the presence of the water layer affects the output voltage and the dominant frequency of the energy harvester. It reveals that the effect of water (or rain) accumulation on the piezoelectric surface should be considered in deriving an optimal operating condition of such energy harvester.

Support for global warming mitigation and the use of CCS: A survey of the Malaysian public

The 2007 Nobel Peace prize was awarded to individuals and groups that had worked hard to address the impending threat of global warming. The award partly serves to highlight to the world the urgency and importance of the global warming issue to humanity. However, questions still remain on the actual public awareness level on global warming and the available technology for its mitigation. This study focused on a Malaysian perspective on these issues. The objectives were achieved with specifically developed questionnaires for gauging the awareness and support level of the respondents. Over a thousand surveys were distributed to the general public via a mix of online and printout survey forms. The responses to the survey were encouraging. Majority of the respondents have heard of or are aware about the global warming issue. Yet, the responses show that there is still a lack of understanding on the climate change drivers. CCS technology is also a rather new mitigation technology and many are still not clear about the details on the role of the technology. It was also noted that there is much support from the respondents with regard to the need for more effort to mitigate climate change, yet there is still some reluctance to contribute in monetary forms to the additional cost required for mitigation. This survey results clearly show that there is still a need to further disseminate information and knowledge on global warming to the general public. In order to minimize confusion and to gain support, details and facts with regards to mitigation technologies should also be part of a wider public education or outreach initiative.

Applied Engineering Failure Analysis: Theory and Practice

This book fills the gap between the traditional failure analysis theory and the actual conducts of the failure cases. The book demonstrates the main methodologies that have evolved from the 1970s to date. Calculation of engineering cases and estimation of system stress and strength are demonstrated in the chapters. A wide range of actual cases span a wide array of engineering fields, including power systems, metallurgy, mining, structures, and machines.

Axial Compression for Direct Capture of Carbon Dioxide (CO2)

One prospective method to retard the speed of climate change is Carbon Capture and Storage (CCS). It is known that reducing emissions through CCS on point sources can only slowdown the rate of increase of atmospheric CO2 concentration and not able to mitigate the CO2 that are already in the atmosphere by previous emissions. Hence, a complimentary method would be to extract CO2 directly from air – Direct Air Capture (DAC). This paper addresses a novel concept of DAC whereby an additional phase of axial compression is introduced to adapt atmospheric air to a level suitable for capture. An axial compression model was developed so that fluid simulation studies can be performed. These information are then utilized in a feasibility study to address several key issues: the additional energy penalty when applying axial compression and whether or not, increasing the capture input by compression would displace the elevated energy consumption.

Overview of Axial Compression Technology for Direct Capture of CO2

Carbon Capture and Storage (CCS) is one of the global leading methods that could potentially retard the speed of climate change. However, CCS on point sources can only slowdown the rate of increase of atmospheric CO2 concentration. In order to mitigate CO2 released by previous emissions, a more proactive alternative is proposed where CO2 is directly extracted and captured from air Direct Air Capture (DAC). This paper presents a technical overview from our current research of a novel DAC concept which features a phase of axial compression to adapt pre-capture atmospheric air to a level suitable for carbon capture. Also detailed in the paper is the feasibility study addressing several key issues: the energy consumption and overall capturing efficiency of the proposed DAC system.

Carbon capture and storage for developing economies: Yhe case for Malaysia

Climate change is fast becoming the environmental and energy concern of the world. There is a dilemma between the continued reliance on fossil fuel for energy and the pressing need to address the problem of greenhouse gas (GHG) emissions from combustion. A potential technology that allows for the consumption of fossil fuel with a minimized emission rate is Carbon Capture and Storage (CCS). Malaysia is a fast developing economy with a historical trend of high reliance on fossil fuel for its energy needs. Therefore, there is compelling motivation to consider CCS for the countrys GHG emission reduction initiative. This paper reviews the potential for carbon capture and storage (CCS) as a part of the climate change mitigation strategy for the Malaysian electricity sector using a technology assessment framework. The suitability and practicality of the technology was reviewed from a broad perspective with a consideration of Malaysia specific conditions. There had been a number of prior assessments on the suitability of CCS as a mitigation technology. Nonetheless, most of these assessments are typically more inclined towards the review from an economic viewpoint and are centered towards the case of developed economies. This study aims to fulfill this gap of knowledge and assess the technology from a broad sense in the Malaysia settings. It is apparent to this assessment that CCS has the potential to play an important role in Malaysias climate change mitigation strategy. However, this study also identified key criteria that would need to be in place for CCS to be an effective climate change mitigation technology for the case of Malaysia.

Dynamics of a piezoelectric energy harvester in a simulated rain environment

Rain impact energy harvesting has proven to be a feasible and potent source of alternative energy. This paper presents the development of a dynamical model for rain impact energy harvester using a piezoelectric beam in simulated rain environment. Most of the conducted works in literature were based on single droplet impact with fixed height and drop position. The main contribution of this paper is to extend the single droplet impact dynamical model by incorporating random drop sizes and drop positions. In this work, a rain simulator is used to generate artificial rain of different rain rates. Following our previous works, the water accumulation on the piezoelectric beam is modeled using added mass coefficient, and impact coefficient is integrated into the dynamical model to describe the post-impact dynamics of the droplet impact. The stochastic nature of the artificial rain is described using rain rate and drop size distribution. Two random number generators are integrated into the model, which are lognormally and uniformly distributed, to generate random numbers for droplet diameter and drop position respectively. The accuracy of the theoretical model is validated experimentally by considering four different rain rates.

System Dynamics of Electric Cars (EC) Usage and Support Infrastructure in Malaysia

Using system dynamics, this paper investigates the feasibility of implementing an integrated infrastructure for Electric Cars (EC) in Malaysia by understanding the intrinsic relationships, compounded effects and dynamics of policies, public knowledge, technology maturity, private investment and network of support infrastructure required upon its deployment in Malaysia. All key enablers are assumed to have a feedback relationship with the demand and the scale of overall EC sold. From the results, it can be concluded that governmental subsidies, environmental policies and effective marketing strategies are needed to support the EC market along technological advancements such as improvement in the ECs battery life.

System Dynamics of a Marine Renewable Energy Scheme (MRE) for Malaysia

MRE provides great potential for Malaysia, an emerging economy, to diversify its primary energy mix and ensuring the security of its energy supply. In this paper, the state-of-the-art of each MRE type is studied alongside hydrographical and geographical conditions of Malaysian waters. It is based upon this knowledge that an MRE scheme is proposed for Malaysia. However, introducing a complex MRE system into Malaysia’s energy pool requires in-depth understanding of key governing factors and the dynamic behaviours of its implementation using a systemic approach. Results from system dynamics modelling have identified key-enablers to fast-track the implementation of MRE in Malaysia.