Open Access. Powered by Scholars. Published by Universities.®
Science and Technology Studies Commons™
Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 9 of 9
Full-Text Articles in Science and Technology Studies
Bottom-Up Microfabrication Process For Individually Controlled Conjugated Polymer Actuators, Alexandre Khaldi, Ali Maziz, Gursel Alici, Geoffrey M. Spinks, Edwin W. Jager
Bottom-Up Microfabrication Process For Individually Controlled Conjugated Polymer Actuators, Alexandre Khaldi, Ali Maziz, Gursel Alici, Geoffrey M. Spinks, Edwin W. Jager
Faculty of Engineering and Information Sciences - Papers: Part A
Handling of soft and fragile sub-millimeter sized samples such as cells and tissues requires new tools that allow delicate manipulation. Conducting polymer actuators show unique characteristics suitable to driving such manipulators, however despite their potential, the current fabrication method of the trilayer structures does not allow constructing advanced micromanipulators operating in air using this technology. Here we show a novel bottom-up microfabrication process for conjugated polymer trilayer actuators using various solid polymer electrolytes. In addition, the process design integrates contact pads, which has been an issue for small scale conducting polymer actuators. The microfabrication process starts with a patterned layer …
Ambient Controlled Synthesis Of Advanced Core-Shell Plasmonic Ag@Zno Photocatalysts, Jinyan Xiong, Qiao Sun, Jun Chen, Zhen Li, S X. Dou
Ambient Controlled Synthesis Of Advanced Core-Shell Plasmonic Ag@Zno Photocatalysts, Jinyan Xiong, Qiao Sun, Jun Chen, Zhen Li, S X. Dou
Faculty of Engineering and Information Sciences - Papers: Part A
Plasmonic Ag@ZnO core-shell hybrids, including hetero-nanowires and hetero-nanoparticles, have been synthesized at room temperature for application in photocatalysis. The morphology, size, crystal structure, and composition of the products were investigated by X-ray diffraction, scanning and transmission electron microscopy, X-ray photoelectron spectroscopy, and ultraviolet-visible spectroscopy. It was found the concentration of Zn(NO3)2·6H2O and the amount of water play crucial roles in the formation of Ag@ZnO core-shell hybrids. The resultant Ag@ZnO core-shell hybrids exhibit much higher photocatalytic activity and stability towards degradation of organic contaminants than pure ZnO nanocrystals under solar light irradiation. The one-dimensional (1D) core-shell hetero-nanowires prepared under optimal conditions …
Controlled And Scalable Torsional Actuation Of Twisted Nylon 6 Fiber, Shazed Aziz, Sina Naficy, Javad Foroughi, Hugh Ralph Brown, Geoffrey M. Spinks
Controlled And Scalable Torsional Actuation Of Twisted Nylon 6 Fiber, Shazed Aziz, Sina Naficy, Javad Foroughi, Hugh Ralph Brown, Geoffrey M. Spinks
Faculty of Engineering and Information Sciences - Papers: Part A
Large-scale torsional actuation occurs in twisted fibers and yarns as a result of volume change induced electrochemically, thermally, photonically, and other means. A quantitative relationship between torsional actuation (stroke and torque) and volume change is here introduced. The analysis is based on experimental investigation of the effects of fiber diameter and inserted twist on the torsional stroke and torque measured when heating and cooling nylon 6 fibers over the temperature range of 26-62 °C. The results show that the torsional stroke depends only on the amount of twist inserted into the fiber and is independent of fiber diameter. The torque …
Stability Enhancement Of Magnetic Levitation Ball System With Two Controlled Electomagnets, Hai Huang, Haiping Du, Weihua Li
Stability Enhancement Of Magnetic Levitation Ball System With Two Controlled Electomagnets, Hai Huang, Haiping Du, Weihua Li
Faculty of Engineering and Information Sciences - Papers: Part A
Magnetic levitation ball system is a highly nonlinear and unstable system. If the system is linearised at the equilibrium point, the achievable balance range of the magnetically levitated ball is very short with one electromagnet. This paper presents an improved magnetic levitation ball system, that contains two electromagnets, where one electromagnet is set above the magnetic ball for pulling, and another one is set under the magnetic ball for pushing. In addition, this paper applies a 2-DOF (degree-of-freedom) PID (proportional-integral-derivative) controller instead of 1-DOF PID for the control of the two electromagnets so that they can work corporately to make …
Controlled Fabrication Of Si Nanoparticles On Graphene Sheets For Li-Ion Batteries, Shenmin Zhu, Chengling Zhu, Jun Ma, Qing Meng, Zaiping Guo, Ziyong Yu, Tao Lu, Yao Li, Di Zhang, Woon Ming Lau
Controlled Fabrication Of Si Nanoparticles On Graphene Sheets For Li-Ion Batteries, Shenmin Zhu, Chengling Zhu, Jun Ma, Qing Meng, Zaiping Guo, Ziyong Yu, Tao Lu, Yao Li, Di Zhang, Woon Ming Lau
Faculty of Engineering and Information Sciences - Papers: Part A
A new route is presented for the synthesis of Si nanoparticle/Graphene (Si-Gr) composite by a sonochemical method and then magnesiothermic reduction process. During the process, silica particles were firstly synthesized and deposited on the surface of graphene oxide (SiO2-GO) by ultrasonic waves, subsequent low-temperature magnesiothermic reduction transformed SiO 2 to Si nanoparticles in situ on graphene sheets. The phase of the obtained materials was influenced by the weight ratio of Mg to SiO 2-GO. With the optimized ratio of 1 : 1, we can get Si nanoparticles on Gr sheets, with the average particle size of Si around 30 nm. …
Enhancing Mechanical Properties Of A Low-Carbon Microalloyed Cast Steel By Controlled Heat Treatment, Jingwei Zhao, Jeong Hun Lee, Yong Woo Kim, Zhengyi Jiang, Chong Soo Lee
Enhancing Mechanical Properties Of A Low-Carbon Microalloyed Cast Steel By Controlled Heat Treatment, Jingwei Zhao, Jeong Hun Lee, Yong Woo Kim, Zhengyi Jiang, Chong Soo Lee
Faculty of Engineering and Information Sciences - Papers: Part A
In the present work, detailed studies were made on the optimization of microstructure and mechanical properties of a low-carbon microalloyed cast steel through control of heat treatment conditions. Specimens were austenitized at temperatures ranging from 950 to 1200 °C for 2 h followed by different cooling methods (furnace, air and water). For analyzing the effect of holding time on mechanical properties, some cast specimens were austenitized at 1100 °C for different times followed by furnace cooling. After heat treatment, mechanical tests were employed to evaluate the room temperature Charpy impact and tensile properties. The characterization of complex precipitates formed during …
A Secure Elliptic Curve Based Rfid Ownership Transfer Scheme With Controlled Delegation, Shu Cheng, Vijay Varadharajan, Yi Mu, Willy Susilo
A Secure Elliptic Curve Based Rfid Ownership Transfer Scheme With Controlled Delegation, Shu Cheng, Vijay Varadharajan, Yi Mu, Willy Susilo
Faculty of Engineering and Information Sciences - Papers: Part A
In practical applications, the owner of an RFID-tagged item canchange. In this paper, we propose a new RFID ownership transfer protocol using elliptic-curve cryptography. The paper first considers security and privacy requirements in the ownership transfer process. Then the paper provides a detailed description of our ownership transfer scheme outlining various protocol phases. Key features of the proposed scheme are that it allows controlled delegation and authorisation recovery, and the ownership transfer is achieved without a trusted third party. We describe a security analysis of the proposed scheme and demonstrate that it meets the desired security and privacy requirements. We …
Multi-Level Controlled Signature, Pairat Thorncharoensri, Willy Susilo, Yi Mu
Multi-Level Controlled Signature, Pairat Thorncharoensri, Willy Susilo, Yi Mu
Faculty of Engineering and Information Sciences - Papers: Part A
In this work, we present and establish a new primitive called Multi-level Controlled Signature. This primitive allows a signer to specify a security level to limit the verifiability of the signature. This primitive works as follows. Without losing generality, we assume the security levels of a group of users are defined in ascending order, where “A” represents the lowest security level and “Z” represents the highest security level, respectively. When a signer signs a message by specifying a security level “C”, all users who have a security level greater than “C” will be able to verify while other users whose …
Low Temperature Synthesis Of Al-Aln Composites From A Nanostructure Made By Controlled Magneto-Ball Milling Of Al In Ammonia, Andrzej Calka, J I. Nikolov, G H. J Wantenaar
Low Temperature Synthesis Of Al-Aln Composites From A Nanostructure Made By Controlled Magneto-Ball Milling Of Al In Ammonia, Andrzej Calka, J I. Nikolov, G H. J Wantenaar
Faculty of Engineering and Information Sciences - Papers: Part A
The formation of an AlN compound in ball milled Al powder in ammonia was studied. In this work a magneto‐ball milling device with controlled ball movement was used. The end milling product was an Al based nanostructure. This product can be transformed into an AlN‐Al nanocomposite upon heating below the melting point of Al. It was found that the level of unreacted Al is dependent on milling time. The maximum amount of AlN was 88.28 wt %. The structure of as‐milled and annealed samples was investigated using x‐ray diffractometry and transmission electron microscopy. Differential thermal analysis was performed on as‐milled …