| 1. |
- Akbar, Muhammad, et al.
(författare)
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Effect of sintering temperature on properties of LiNiCuZn-Oxide: a potential anode for solid oxide fuel cell
- 2019
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Ingår i: Materials Research Express. - : IOP PUBLISHING LTD. - 2053-1591. ; 6:10
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Tidskriftsartikel (refereegranskat)abstract
- Crystal structure and surface morphology play vital role in the performance of Solid Oxide Fuel cells (SOFCs) anode. Sufficient electrocatalytic activity and high conductivity are the key requirements for anode to enhance the electrochemical capability. In current work, sintering temperature effects are investigated on the properties of advanced LiNiCuZn-Oxide based electrode for solid oxide fuel cells (SOFCs). The powders were prepared by simple solid-state reaction method was followed by sintering at different temperatures (700 degrees C-1200 degrees C). Moreover, various characterization techniques have been employed to investigate the sintering temperatures effects on the crystallite size, morphology, particle size, energy band gap and absorption peaks. The energy gap (Eg) was observed to increase from 2.94 eV to 3.32 eV and dc conductivity decreased from 9.084 Scm(-1) to 0.46 Scm(-1) by increasing sintering temperature from 700 degrees C to 1200 degrees C. Additionally, the best fuel cell performance of 0.90 Wcm(-2) was achieved for LiNiCuZn-Oxide sintered at 700 degrees C using H-2/air as a fuel and oxidant and it decreased to 0.17 Wcm(-2) for powders sintered at 1200 degrees C. Based on these results, we can conclude that 700 degrees C is the best optimum temperature for these chemical compositions, where all parameters of electrode are as per SOFCs requirement.
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| 2. |
- Baloch, Naveed Khan, et al.
(författare)
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Defender : A Low Overhead and Efficient Fault-Tolerant Mechanism for Reliable on-Chip Router
- 2019
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Ingår i: IEEE Access. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 2169-3536. ; 7, s. 142843-142854
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Tidskriftsartikel (refereegranskat)abstract
- The ever-shrinking size of a transistor has made Network on Chip (NoC) susceptible to faults. A single error in the NoC can disrupt the entire communication. In this paper, we introduce Defender, a fault-tolerant router architecture, that is capable of tolerating permanent faults in all the parts of the router. We intend to employ structural modifications in baseline router design to achieve fault tolerance. In Defender we provide the fault tolerance to the input ports and routing computation unit by grouping the neighboring ports together. Default winner strategy is used to provide fault resilience to the virtual channel arbiters and switch allocators. Multiple routes are provided to the crossbar to tolerate the faults. Defender provides improved fault tolerance to all stages of routers as compared to the currently prevailing fault tolerant router architectures. Reliability analysis using silicon protection factor (SPF) and Mean Time to Failure (MTTF) metrics confirms that our proposed design Defender is 10.78 times more reliable than baseline unprotected router and then the current state of the art architectures.
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| 3. |
- Dong, Wenjing, et al.
(författare)
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All in One Multifunctional Perovskite Material for Next Generation SOFC
- 2016
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Ingår i: Electrochimica Acta. - : Elsevier. - 0013-4686 .- 1873-3859. ; 193, s. 225-230
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Tidskriftsartikel (refereegranskat)abstract
- Multifunctional roles of La0.2Sr0.25Ca0.45TiO3 (LSCT) perovskite material as anode, cathode, and electrolyte for low temperature solid oxide fuel cell (LT-SOFC) are discovered for the first time, and have been investigated via electrochemical impedance spectroscopy (EIS) and fuel cell (FC) measurements. LSCT resistance decreases prominently in FC environment as shown in this study. An improved performance was observed by compositing LSCT with samaria doped ceria (SDC) at 550 degrees C when the FC power density increased from tens of mW cm(-2) for the pure LSCT system up to hundreds of mW cm(-2). The improved conductivity of LSCT-SDC composite is highlighted. The multifunctionality of LSCT as cathode, anode and electrolyte could be attributed to different conducting behavior at high and low oxygen partial pressures and ionic conduction at intermediate oxygen partial pressures. These new discoveries not only indicate great potential for exploring multifunctional perovskites for the next generation SOFC, but also deepen SOFC science and develop new technologies.
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| 4. |
- Malik, Naveed ur Rehman, 1985-, et al.
(författare)
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Challenges of Real-Time Parameter Estimation of a DFIG using Synchrophasors
- 2015
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Ingår i: 2015 IEEE 15TH INTERNATIONAL CONFERENCE ON ENVIRONMENT AND ELECTRICAL ENGINEERING (IEEE EEEIC 2015). - : IEEE. - 9781479979929 ; , s. 1939-1944
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Konferensbidrag (refereegranskat)abstract
- This paper explores the challenges faced during the utilization of synchrophasors received from PMUs in order to estimate the parameters of a DFIG in a real-time. PMUs are installed at the stator and rotor terminals of an 11-KVA DFIG, in order to provide high resolution synchrophasor data at a reporting rate of 50 msgs/sec. These synchrophasors are processed in real-time using an embedded controller in order to measure and estimate the internal parameters of the generator, i.e., magnetization and leakage inductances. Closed-loop variable speed drive, active power and reactive power controls are implemented for the DFIG. This paper discusses the laboratory setup, control and parameter estimation experiments carried out on the DFIG. The testing process, challenges faced, and overall experimental findings are also presented.
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| 5. |
- Muhammad, Naveed, 1983-, et al.
(författare)
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Intention Estimation Using Set of Reference Trajectories as Behaviour Model
- 2018
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Ingår i: Sensors. - Basel : MDPI. - 1424-8220. ; 18:12
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Tidskriftsartikel (refereegranskat)abstract
- Autonomous robotic systems operating in the vicinity of other agents, such as humans, manually driven vehicles and other robots, can model the behaviour and estimate intentions of the other agents to enhance efficiency of their operation, while preserving safety. We propose a data-driven approach to model the behaviour of other agents, which is based on a set of trajectories navigated by other agents. Then, to evaluate the proposed behaviour modelling approach, we propose and compare two methods for agent intention estimation based on: (i) particle filtering; and (ii) decision trees. The proposed methods were validated using three datasets that consist of real-world bicycle and car trajectories in two different scenarios, at a roundabout and at a t-junction with a pedestrian crossing. The results validate the utility of the data-driven behaviour model, and show that decision-tree based intention estimation works better on a binary-class problem, whereas the particle-filter based technique performs better on a multi-class problem, such as the roundabout, where the method yielded an average gain of 14.88 m for correct intention estimation locations compared to the decision-tree based method. © 2018 by the authors
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| 6. |
- Muhammad, Naveed, 1983-, et al.
(författare)
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Predicting Agent Behaviour and State for Applications in a Roundabout-Scenario Autonomous Driving
- 2019
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Ingår i: Sensors. - Basel : MDPI. - 1424-8220. ; 19:19
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Tidskriftsartikel (refereegranskat)abstract
- As human drivers, we instinctively employ our understanding of other road users' behaviour for enhanced efficiency of our drive and safety of the traffic. In recent years, different aspects of assisted and autonomous driving have gotten a lot of attention from the research and industrial community, including the aspects of behaviour modelling and prediction of future state. In this paper, we address the problem of modelling and predicting agent behaviour and state in a roundabout traffic scenario. We present three ways of modelling traffic in a roundabout based on: (i) the roundabout geometry; (ii) mean path taken by vehicles inside the roundabout; and (iii) a set of reference trajectories traversed by vehicles inside the roundabout. The roundabout models are compared in terms of exit-direction classification and state (i.e., position inside the roundabout) prediction of query vehicles inside the roundabout. The exit-direction classification and state prediction are based on a particle-filter classifier algorithm. The results show that the roundabout model based on set of reference trajectories is better suited for both the exit-direction and state prediction.
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| 7. |
- Mushtaq, Naveed, et al.
(författare)
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Tuning the Energy Band Structure at Interfaces of the SrFe0.75Ti0.25O3-delta-Sm0.25Ce0.75O2-delta Heterostructure for Fast Ionic Transport
- 2019
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Ingår i: ACS Applied Materials and Interfaces. - : AMER CHEMICAL SOC. - 1944-8244 .- 1944-8252. ; 11:42, s. 38737-38745
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Tidskriftsartikel (refereegranskat)abstract
- Interface engineering holds huge potential for enabling exceptional physical properties in heterostructure materials via tuning properties at the atomic level. In this study, a heterostructure built by a new redox stable semiconductor SrFe0.75Ti0.25O3-delta (SFT) and an ionic conductor Sm0.25Ce0.75O2 (SDC) is reported. The SFT-SDC heterostructure exhibits a high ionic conductivity >0.1 S/cm at 520 degrees C, which is 1 order of magnitude higher than that of bulk SDC. When it was applied into the fuel cell, the SFT-SDC can realize favorable electrolyte functionality and result in an excellent power density of 920 mW cm(-2) at 520 degrees C. The prepared SFT-SDC heterostructure materials possess both electronic and ionic conduction, where electron states modulate local electrical field to facilitate ion transport. Further investigations to calculate the structure and electronic structure/state of SFT and SDC are done using density functional theory (DFT). It is found that the reconstruction of the energy band at interfaces is responsible for such enhanced ionic conductivity and cell power output. The current study about the perovskite-based heterostructure presents a novel strategy for developing advanced ceramic fuel cells.
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| 8. |
- Yaqoob, Muhammad Atif, et al.
(författare)
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Source Localization Using Virtual Antenna Arrays
- 2015
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Ingår i: 2015 International Conference on Localization and GNSS (ICL-GNSS). - 9781479998586
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Konferensbidrag (refereegranskat)abstract
- Using antenna arrays for direction of arrival (DoA) estimation and source localization is a well-researched topic. In this paper, we analyze virtual antenna arrays for DoA estimation where the antenna array geometry is acquired using data from a low-cost inertial measurement unit (IMU). Performance evaluation of an unaided inertial navigation system with respect to individual IMU sensor noise parameters is provided using a state space based extended Kalman filter. Secondly, using Monte Carlo simulations, DoA estimation performance of random 3-D antenna arrays is evaluated by computing Cramér-Rao lower bound values for a single plane wave source located in the far field of the array. Results in the paper suggest that larger antenna arrays can provide significant gain in DoA estimation accuracy, but, noise in the rate gyroscope measurements proves to be a limiting factor when making virtual antenna arrays for DoA estimation and source localization using single antenna devices.
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