Universiti Teknologi Malaysia

About: Universiti Teknologi Malaysia is a education organization based out in Johor Bahru, Malaysia. It is known for research contribution in the topics: Membrane & Adsorption. The organization has 21644 authors who have published 39500 publications receiving 520635 citations.

Distributed and Collaborative Beamforming in Wireless Sensor Networks: Classifications, Trends, and Research Directions

Abstract: Distributed and collaborative beamforming (DCBF) scheme in wireless sensor networks (WSNs) is receiving new-found interest in recent times due to the rapid advancements in wireless technology and embedded systems. Although studies on distributed and collaborative beamforming have been carried out for more than ten years, the DCBF was initially considered impractical due to high complexity and hardly achievable requirements. It gained prominence only in the past few years as small wireless communication electronic sensors with high processing capability became easily available. Recent works showcasing distributed and collaborative beamforming as a suitable solution for 5G communication systems such as mm-wave communication and machine to machine communications has further ignited the interest in this research field. Motivated by these factors, this paper presents a survey on the research trends of distributed and collaborative beamforming in WSNs. We provide classifications of the DCBF research areas and conduct an extensive review of the various proposals which have appeared in the literature for each classification. This survey uncovered that majority of existing research can be broadly divided into four major research trends: beampattern analysis, power and lifetime optimization, synchronization, and finally, prototype design. The inherent features, constraints and challenges of each research category in the distributed and collaborative beamforming are presented and the lessons learned from the shortcomings of previous research are summarized. Finally, this paper has unveiled open research directions in the field of distributed and collaborative beamforming in WSNs.

A Survey of Routing Protocols in Wireless Body Sensor Networks

Abstract: Wireless Body Sensor Networks (WBSNs) constitute a subset of Wireless Sensor Networks (WSNs) responsible for monitoring vital sign-related data of patients and accordingly route this data towards a sink. In routing sensed data towards sinks, WBSNs face some of the same routing challenges as general WSNs, but the unique requirements of WBSNs impose some more constraints that need to be addressed by the routing mechanisms. This paper identifies various issues and challenges in pursuit of effective routing in WBSNs. Furthermore, it provides a detailed literature review of the various existing routing protocols used in the WBSN domain by discussing their strengths and weaknesses.

Methanation of carbon dioxide on metal-promoted mesostructured silica nanoparticles

Abstract: a b s t r a c t Metal-promoted mesostructured silica nanoparticles (MSN) have been studied for CO2 methanation under atmospheric pressure. In term of activities, high activity was observed on Rh/MSN, Ru/MSN, Ni/MSN, Ir/MSN, Fe/MSN and Cu/MSN at and above 623 K. However, on an areal basis, Ni/MSN was the most active catalyst, while Ir/MSN was the poorest catalyst. The catalysts have also been studied for elu- cidation of the role of each metal, MSN and metal/MSN in CO2 methanation by in situ FTIR spectroscopy studies. Firstly, CO2 and H2 was adsorbed and dissociated on metal sites to form CO, O and H atoms, followed by migration onto the MSN surface. The dissociated CO then interacted with oxide surfaces of MSN to form bridged carbonyl and linear carbonyl, while the presence of H atom facilitated the formation of bidentate formate. These three species could be responsible for the formation of methane. However, the bidentate formate species could be the main route to formation of methane. MSN support has been found to play an important role in the mechanism. MSN support served the sites for carbonyl species which act as precursors to methane formation. These results provided new perspectives in the catalysis, particularly in the recycling of CO2. © 2014 Elsevier B.V. All rights reserved.