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Articles 61 - 90 of 114

Full-Text Articles in Science and Technology Studies

Optimal Design For Energy-Efficient Per-Subcarrier Antenna Selection Mimo–Ofdm Wireless Systems, Ngoc Phuc Le, Le Chung Tran, Farzad Safaei Jan 2015

Optimal Design For Energy-Efficient Per-Subcarrier Antenna Selection Mimo–Ofdm Wireless Systems, Ngoc Phuc Le, Le Chung Tran, Farzad Safaei

Faculty of Engineering and Information Sciences - Papers: Part A

In this paper, we consider a novel optimal design for per-subcarrier antenna selection multi-input multi-output orthogonal frequency division multiplexing systems from an energy-efficiency perspective. The optimal number of antennas, i.e., the number of radio frequency chains, that needs to be built-in on a transmitter to achieve the maximum energy-efficiency is determined. Specifically, an optimization problem for maximizing the average energy-efficiency with respect to the number of antennas is formulated. To solve this optimization problem, we first derive a closed-form formula expressing the cost function (i.e., the average energy-efficiency) as a function of the number of antennas. Search algorithms are then …


Energy Spectra Considerations For Synchrotron Radiotherapy Trials On The Id17 Bio-Medical Beamline At The European Synchrotron Radiation Facility, Jeffrey C. Crosbie, Pauline Fournier, Stefan Bartzsch, Mattia Donzelli, Iwan Cornelius, Andrew W. Stevenson, Herwig Requardt, Elke Brauer-Krisch Jan 2015

Energy Spectra Considerations For Synchrotron Radiotherapy Trials On The Id17 Bio-Medical Beamline At The European Synchrotron Radiation Facility, Jeffrey C. Crosbie, Pauline Fournier, Stefan Bartzsch, Mattia Donzelli, Iwan Cornelius, Andrew W. Stevenson, Herwig Requardt, Elke Brauer-Krisch

Faculty of Engineering and Information Sciences - Papers: Part A

The aim of this study was to validate the kilovoltage X-ray energy spectrum on the ID17 beamline at the European Synchrotron Radiation Facility (ESRF). The purpose of such validation was to provide an accurate energy spectrum as the input to a computerized treatment planning system, which will be used in synchrotron microbeam radiotherapy trials at the ESRF. Calculated and measured energy spectra on ID17 have been reported previously but recent additions and safety modifications to the beamline for veterinary trials warranted a fresh investigation. The authors used an established methodology to compare X-ray attenuation measurements in copper sheets (referred to …


Working In Partnership To Develop Engineering Capacity In Energy Efficiency, Cheryl Desha, Duane A. Robinson, Alistair Sproul Jan 2015

Working In Partnership To Develop Engineering Capacity In Energy Efficiency, Cheryl Desha, Duane A. Robinson, Alistair Sproul

Faculty of Engineering and Information Sciences - Papers: Part A

Energy efficiency is a complex topic to integrate into higher education curricula, with limited success internationally or in Australia. This paper discusses one of the successful initiatives within the Energy Efficiency Training Program, which was jointly managed and implemented by the New South Wales Office of Environment and Heritage and Department of Education and Communities. The state government initiative aimed to increase the knowledge and skills of the New South Wales workforce, help business to identify and implement energy efficiency projects, and provide professional development for the training providers. Key sectors targeted included property, construction, manufacturing and services. The Program …


Synchrotron Radiation Based Experimental Determination Of The Optimal Energy For Cell Radiotoxicity Enhancement Following Photoelectric Effect On Stable Iodinated Compounds, S Corde, A Joubert, J F. Adam, A M. Charvet, J F. Le Bas, F Esteve, H Elleaume, J Balosso Feb 2014

Synchrotron Radiation Based Experimental Determination Of The Optimal Energy For Cell Radiotoxicity Enhancement Following Photoelectric Effect On Stable Iodinated Compounds, S Corde, A Joubert, J F. Adam, A M. Charvet, J F. Le Bas, F Esteve, H Elleaume, J Balosso

Stéphanie Corde

This study was designed to experimentally evaluate the optimal X-ray energy for increasing the radiation energy absorbed in tumours loaded with iodinated compounds, using the photoelectric effect. SQ20B human cells were irradiated with synchrotron monochromatic beam tuned at 32.8, 33.5, 50 and 70 keV. Two cell treatments were compared to the control: cells suspended in 10 mg ml1 of iodine radiological contrast agent or cells pre-exposed with 10 mM of iodo-desoxyuridine (IUdR) for 48 h. Our radiobiological end point was clonogenic cell survival. Cells irradiated with both iodine compounds exhibited a radiation sensitisation enhancement. Moreover, it was energy dependent, with …


Adaptive Stochastic Energy Flow Balancing In Smart Grid, Hassan Shirzeh, Fazel Naghdy, Philip Ciufo, Montserrat Ros Jan 2014

Adaptive Stochastic Energy Flow Balancing In Smart Grid, Hassan Shirzeh, Fazel Naghdy, Philip Ciufo, Montserrat Ros

Dr Philip Ciufo

A smart grid can be considered as an unstructured network of distributed interacting nodes represented by renewable energy sources, storage and loads. The nodes emerge or disappear in a stochastic manner due to the intermittent nature of natural sources such as wind speed and solar irradiation. Prediction and stochastic modelling of electrical energy flow is a critical characteristic in such a network to achieve load balancing and/or peak shaving in order to minimise the fluctuation between off peak and peak demand by power consumers. Before contributing energy to the network, a node acquires information about other nodes in the grid …


Balancing Energy In The Smart Grid Using Distributed Value Function (Dvf), Hassan Shirzeh, Fazel Naghdy, Philip Ciufo, Montserrat Ros Jan 2014

Balancing Energy In The Smart Grid Using Distributed Value Function (Dvf), Hassan Shirzeh, Fazel Naghdy, Philip Ciufo, Montserrat Ros

Faculty of Engineering and Information Sciences - Papers: Part A

As the penetration of renewable energy resources increases in distribution networks, so does the need to manage these resources in an effective manner. Since these resources are installed to displace carbon-based generation and to provide an income stream to the resource owner, it is important that both installation objectives (as a minimum) can be met. With all of these renewable energy resources available, the opportunity also exists to assist with the energy management of this resource-rich distribution network. However, the renewable energy resources do not produce power in a deterministic manner. The available production depends on the time of day …


Development Of High Melting Temperature Microencapsulated Phase Change Material For Compacted Thermal Energy Storage Bed, Weiguang Su, Jo Darkwa, Georgios Kokogiannakis Jan 2014

Development Of High Melting Temperature Microencapsulated Phase Change Material For Compacted Thermal Energy Storage Bed, Weiguang Su, Jo Darkwa, Georgios Kokogiannakis

Faculty of Engineering and Information Sciences - Papers: Part A

In this paper a novel high temperature microencapsulated phase change material (MEPCM) based on paraffin as the core material and MF resin as the shell material has been developed with the in-situ polymerization method for solar hot water storage application. The results showed that the type of emulsifier could influence core material content, the encapsulation efficiency as well as the latent heat capacity. Based on the results and analysis the study has shown that energy storage density could be increased by as much as 59% if 60wt% of MEPCM 1 was to be used in the proposed compacted MEPCM-water bed …


Low-Energy Positron And Electron Scattering From Tetrahydrofuran And 3-Hydroxy-Tetrahydrofuran, James P. Sullivan, Luca Chiari, Emma Anderson, Wade Tattersall, Prasanga Palihawadana, J R. Machacek, Casten Makochekanwa, R P. Mceachran, Stephen J. Buckman, M J. Brunger, Gustavo Garcia, Francisco Blanco Jan 2014

Low-Energy Positron And Electron Scattering From Tetrahydrofuran And 3-Hydroxy-Tetrahydrofuran, James P. Sullivan, Luca Chiari, Emma Anderson, Wade Tattersall, Prasanga Palihawadana, J R. Machacek, Casten Makochekanwa, R P. Mceachran, Stephen J. Buckman, M J. Brunger, Gustavo Garcia, Francisco Blanco

Faculty of Engineering and Information Sciences - Papers: Part A

We present new cross section results from a joint experimental and theoretical investigation into low-energy positron and electron scattering from two targets of biological interest, namely tetrahydrofuran and 3-hydroxy-tetrahydrofuran. We compare and discuss the total, elastic and inelastic cross sections for these species in the light of potential positron and electron-induced damage in biomolecular systems.


Novel Algorithms For Complete Targets Coverage In Energy Harvesting Wireless Sensor Networks, Changlin Yang, Kwan-Wu Chin Jan 2014

Novel Algorithms For Complete Targets Coverage In Energy Harvesting Wireless Sensor Networks, Changlin Yang, Kwan-Wu Chin

Faculty of Engineering and Information Sciences - Papers: Part A

This paper addresses the problem of maximizing the network lifetime of rechargeable Wireless Sensor Networks (WSNs) whilst ensuring all targets are monitored continuously by at least one sensor node. The objective is to determine a group of sensor nodes, and their wake-up schedule such that within a time interval, one subset of nodes are active whilst others enter the sleep state to conserve energy as well as recharge their battery. We propose a Linear Programming (LP) based solution to determine the activation schedule of sensor nodes whilst affording them recharging opportunities and at the same time ensures complete target coverage. …


Low-Energy Electron Scattering From Α-Tetrahydrofurfuryl Alcohol, Luca Chiari, Darryl Jones, Penny Thoi, Michael J. Brungei, Gustavo Garcia, Francisco Blanco Jan 2014

Low-Energy Electron Scattering From Α-Tetrahydrofurfuryl Alcohol, Luca Chiari, Darryl Jones, Penny Thoi, Michael J. Brungei, Gustavo Garcia, Francisco Blanco

Faculty of Engineering and Information Sciences - Papers: Part A

We report on differential cross section results for low-energy electron collisions with the biologically relevant species a-tetrahydrofurfuryl alcohol. Electron-impact excitation measurements of the electronic states of a-tetrahydrofurfuryl alcohol were carried out at incident energies between 15-50 eV and for scattering angles in the range 20-90 degrees. Elastic differential cross section have also been calculated within the Independent Atom Model and using the Screening Corrected Additivity Rule approach at selected energies between 1-1000 eV.


A Noniterative Method To Estimate Load Carrying Capability Of Generating Units In A Renewable Energy Rich Power Grid, Md Abu Abdullah, Kashem M. Muttaqi, Ashish Agalgaonkar, Danny Soetanto Jan 2014

A Noniterative Method To Estimate Load Carrying Capability Of Generating Units In A Renewable Energy Rich Power Grid, Md Abu Abdullah, Kashem M. Muttaqi, Ashish Agalgaonkar, Danny Soetanto

Faculty of Engineering and Information Sciences - Papers: Part A

It is important to estimate the contribution of renewable generation units in the evaluation of system generation adequacy for power generation planning taking into account the demand and renewable generation correlation and uncertainty. The effective load carrying capability (ELCC) is usually used for this purpose. In this paper, a noniterative analytical method is proposed for estimating the peak load carrying capability (PLCC) and ELCC of conventional and renewable generation units. The proposed method is verified using the IEEE RTS and an electricity network in New South Wales, Australia, and the results are compared with other estimation methods. The results show …


Energy-Efficiency Analysis Of Per-Subcarrier Antenna Selection With Peak-Power Reduction In Mimo-Ofdm Wireless Systems, Ngoc Phuc Le, Le Chung Tran, Farzad Safaei Jan 2014

Energy-Efficiency Analysis Of Per-Subcarrier Antenna Selection With Peak-Power Reduction In Mimo-Ofdm Wireless Systems, Ngoc Phuc Le, Le Chung Tran, Farzad Safaei

Faculty of Engineering and Information Sciences - Papers: Part A

The use of per-subcarrier antenna subset selection in OFDM wireless systems offers higher system capacity and/or improved link reliability.However, the implementation of the conventional per-subcarrier selection schememay result in significant fluctuations of the average power and peak power across antennas, which affects the potential benefits of the system. In this paper, power efficiency of high-power amplifiers and energy efficiency in per-subcarrier antenna selection MIMO-OFDM systems are investigated. To deliver the maximum overall power efficiency, we propose a two-step strategy for data-subcarrier allocation.This strategy consists of an equal allocation of data subcarriers based on linear optimization and peak-power reduction via cross-antenna …


Role Of The Compaction Energy Level On The Small Strain Stiffness Of A Silty Sand Soil Subjected To Wetting And Drying, A Heitor, B Indraratna, C Rujikiatkamjorn Jan 2014

Role Of The Compaction Energy Level On The Small Strain Stiffness Of A Silty Sand Soil Subjected To Wetting And Drying, A Heitor, B Indraratna, C Rujikiatkamjorn

Faculty of Engineering and Information Sciences - Papers: Part A

The dynamic properties of a soil are routinely quantified to describe its engineering behaviour under repeated loading. While the results of previous research studies indicate that the effect of changes in suction on the dynamic response is significant, only limited research has been engaged in the assessment of post-compacted changes in suction induced by cycles of wetting and drying. In this paper, aspects related to the dynamic properties with special reference to small strain shear modulus behaviour at different compaction energy levels are described and outlined. Particular emphasis is placed on the hysteric behaviour observed (i.e. amplitude of the hysteresis …


Adaptive Antenna Selection For Energy-Efficient Mimo-Ofdm Wireless Systems, Ngoc Phuc Le, Le Chung Tran, Farzad Safaei Jan 2014

Adaptive Antenna Selection For Energy-Efficient Mimo-Ofdm Wireless Systems, Ngoc Phuc Le, Le Chung Tran, Farzad Safaei

Faculty of Engineering and Information Sciences - Papers: Part A

In this paper, we investigate energy-efficiency in antenna selection OFDM-based systems. We show that an OFDM system with conventional antenna selection approaches, including per-subcarrier selection (i.e., selecting antennas independently for each subcarrier) and bulk-selection (i.e., choosing the same antennas for all subcarriers), suffers from a significant loss in energy-efficiency. To achieve a better energy-efficiency performance, we propose an adaptive antenna selection scheme where both the number of active RF (radio frequency) chains and the antenna indices are selected depending on the channel condition. This selection scheme could be implemented by exhaustive search. Moreover, we develop an algorithm that achieves a …


Support For The Integration Of Green Roof Constructions Within Chinese Building Energy Performance Policies, Georgios Kokogiannakis, Jo Darkwa Jan 2014

Support For The Integration Of Green Roof Constructions Within Chinese Building Energy Performance Policies, Georgios Kokogiannakis, Jo Darkwa

Faculty of Engineering and Information Sciences - Papers: Part A

Green roofs could act as a thermal buffer in buildings and offer potential energy savings. However, the energy benefits from green roofs are not usually properly recognised by traditional building energy regulations. Building energy regulations are traditionally over-simplistic during the assessment of the energy performance of complex building constructions. In the case of green roof designs, it is essential that the assessment mechanisms should not ignore the complex heat and moisture balances within the green roof layers. In this paper, dynamic energy modelling that considers the complexity within the green roof layers is adopted to guide policy makers in China …


A Combined Experimental And Simulation Method For Appraising The Energy Performance Of Green Roofs In Ningbo's Chinese Climate, Georgios Kokogiannakis, Jo Darkwa, Kate Yuan Jan 2014

A Combined Experimental And Simulation Method For Appraising The Energy Performance Of Green Roofs In Ningbo's Chinese Climate, Georgios Kokogiannakis, Jo Darkwa, Kate Yuan

Faculty of Engineering and Information Sciences - Papers: Part A

A passive means of lowering the energy demand of buildings is the application of green roofs. The complexity between heat and moisture exchanges in green roof layers and the large variations of green roof types make the need for experimental or simulation assessments necessary for quantifying the energy benefits from green roofs. The current treatment of green roofs in simulation programs is either over-simplistic, for example by ignoring heat and moisture exchanges such as evapotranspiration, or the more advanced models have limitations and require inputs that are rarely available in practice. In this paper a combination of experimental and modelling …


Development Of Databases For Facilitating Green Roof Energy Simulation Assessments, Aloysius Decruz, Georgios Kokogiannakis, Jo Darkwa, Kate Yuan, Paul Strachan Jan 2014

Development Of Databases For Facilitating Green Roof Energy Simulation Assessments, Aloysius Decruz, Georgios Kokogiannakis, Jo Darkwa, Kate Yuan, Paul Strachan

Faculty of Engineering and Information Sciences - Papers: Part A

Assessments of the energy performance of green roofs have traditionally been performed with experimental and modelling procedures. Experimental green roof energy studies have significant disadvantages (expensive, time-consuming, cannot be generalised, etc.). On the other hand, modelling studies are often done with over-simplified models (for example, by ignoring the effect of moisture flows in the green roof layers) or with detailed models that require inputs which are often difficult to be obtained in practice and may involve a certain degree of uncertainty. This paper describes the methodologies for the development of databases that include data inputs that could be used within …


Climate Change Mitigation With Integration Of Renewable Energy Resources In The Electricity Grid Of New South Wales, Australia, Md Abu Abdullah, Ashish Agalgaonkar, Kashem M. Muttaqi Jan 2014

Climate Change Mitigation With Integration Of Renewable Energy Resources In The Electricity Grid Of New South Wales, Australia, Md Abu Abdullah, Ashish Agalgaonkar, Kashem M. Muttaqi

Faculty of Engineering and Information Sciences - Papers: Part A

The implementation of climate change mitigation strategies may significantly affect the current practices for electricity network operation. Increasing penetration of renewable energy generation technologies into electricity networks is one of the key mitigation strategies to achieve greenhouse gas emission reduction targets. Additional climate change mitigation strategies can also contribute to emission reduction thereby supplementing the renewable energy generation participation, which may be limited due to technical constraints of the network. In this paper, the penetration requirements for different renewable energy generation resources are assessed while concurrently examining other mitigation strategies to reduce overall emissions from electricity networks and meet requisite …


A Novel Approach For Ramp-Rate Control Of Solar Pv Using Energy Storage To Mitigate Output Fluctuations Caused By Cloud Passing, M J. E Alam, K M. Muttaqi, D Sutanto Jan 2014

A Novel Approach For Ramp-Rate Control Of Solar Pv Using Energy Storage To Mitigate Output Fluctuations Caused By Cloud Passing, M J. E Alam, K M. Muttaqi, D Sutanto

Faculty of Engineering and Information Sciences - Papers: Part A

The variability of solar irradiance with a high ramp-rate, caused by cloud passing, can create fluctuation in the PV output. In a weak distribution grid with a high PV penetration, this can create significant voltage fluctuations. Energy storage devices are used to smooth out the fluctuation using traditional moving average control. However, moving average does not control the ramp-rate directly; rather the ramp-rate depends on previous values of PV output. This paper proposes a strategy where the ramp-rate of PV panel output is used to control the PV inverter ramp-rate to a desired level by deploying energy storage (which can …


Optimal Energy For Cell Radiosensitivity Enhancement By Gold Nanoparticles Using Synchrotron-Based Monoenergetic Photon Beams, Wan Nordiana Rahman, Stephanie Corde, Naoto Yagi, Siti Aishah Abdul Aziz, Nathan Annabell, Moshi Geso Jan 2014

Optimal Energy For Cell Radiosensitivity Enhancement By Gold Nanoparticles Using Synchrotron-Based Monoenergetic Photon Beams, Wan Nordiana Rahman, Stephanie Corde, Naoto Yagi, Siti Aishah Abdul Aziz, Nathan Annabell, Moshi Geso

Faculty of Engineering and Information Sciences - Papers: Part A

Gold nanoparticles have been shown to enhance radiation doses delivered to biological targets due to the high absorption coefficient of gold atoms, stemming from their high atomic number (Z) and physical density. These properties significantly increase the likelihood of photoelectric effects and Compton scattering interactions. Gold nanoparticles are a novel radiosensitizing agent that can potentially be used to increase the effectiveness of current radiation therapy techniques and improve the diagnosis and treatment of cancer. However, the optimum radiosensitization effect of gold nanoparticles is strongly dependent on photon energy, which theoretically is predicted to occur in the kilovoltage range of energy. …


Australia's Transport Is Falling Behind On Energy Efficiency, Philip Laird Jan 2014

Australia's Transport Is Falling Behind On Energy Efficiency, Philip Laird

Faculty of Engineering and Information Sciences - Papers: Part A

Australia has scored poorly in the energy efficiency of its land transport, and is well behind other major economies, a recent international scorecard has revealed. That means Australians are using more energy to travel each kilometre than people in developed nations such as the US, and major emerging economies such as China, Brazil, and India.


Distribution Expansion Planning Considering Reliability And Security Of Energy Using Modified Pso (Particle Swarm Optimization) Algorithm, Jamshid Aghaei, Kashem M. Muttaqi, Ali Azizivahed, Mohsen Gitizadeh Jan 2014

Distribution Expansion Planning Considering Reliability And Security Of Energy Using Modified Pso (Particle Swarm Optimization) Algorithm, Jamshid Aghaei, Kashem M. Muttaqi, Ali Azizivahed, Mohsen Gitizadeh

Faculty of Engineering and Information Sciences - Papers: Part A

Distribution feeders and substations need to provide additional capacity to serve the growing electrical demand of customers without compromising the reliability of the electrical networks. Also, more control devices, such as DG (Distributed Generation) units are being integrated into distribution feeders. Distribution networks were not planned to host these intermittent generation units before construction of the systems. Therefore, additional distribution facilities are needed to be planned and prepared for the future growth of the electrical demand as well as the increase of network hosting capacity by DG units. This paper presents a multiobjective optimization algorithm for the MDEP (Multi-Stage Distribution …


Comparative Analysis Of Dynamic Line Rating Models And Feasibility To Minimise Energy Losses In Wind Rich Power Networks, Mathew Simms, Lasantha Meegahapola Dec 2013

Comparative Analysis Of Dynamic Line Rating Models And Feasibility To Minimise Energy Losses In Wind Rich Power Networks, Mathew Simms, Lasantha Meegahapola

Dr Lasantha G Meegahapola

Wind power generation has indicated an exponential increase during last two decades and existing transmission network infrastructure is increasingly becoming inadequate to transmit remotely generated wind power to load centres in the network. The dynamic line rating (DLR) is one of the viable solutions to improve the transmission line ampacity during high wind penetration without investing on an additional transmission network. The main objective of this study is to identify the basic differences between two main line rating standards, since transmission network service providers (TNSPs) heavily depend on these two standards when developing their line rating models. Therefore, a parameter …


Dynamic Characteristics Of A Hybrid Microgrid With Inverter And Non- Inverter Interfaced Renewable Energy Sources: A Case Study, A V. Jayawardena, L G. Meegahapola, S Perera, D A. Robinson Dec 2013

Dynamic Characteristics Of A Hybrid Microgrid With Inverter And Non- Inverter Interfaced Renewable Energy Sources: A Case Study, A V. Jayawardena, L G. Meegahapola, S Perera, D A. Robinson

Dr Lasantha G Meegahapola

Microgrids are becoming important constituents of electric power distribution networks. Microgrids are typically comprised of both inverter interfaced (e.g. double-fed induction generator (DFIG), solar-photovoltaic (PV) system) and non-inverter interfaced (e.g. synchronous generator) renewable energy generators (REGs), hence their dynamic characteristics are significantly different from the conventional grids comprised of centralised synchronous generators. Different inherent characteristics of REGs, power dispatch levels, relative REG capacities, and external grid characteristics are some of the important features of significant interest in relation to microgrid dynamic behaviour. For this study a microgrid model was developed in DIgSILENT Power Factory based on the IEEE-13 bus system …


Conversion Of Greenhouse Gasses Into Energy, Sarah C. Rippe Sep 2013

Conversion Of Greenhouse Gasses Into Energy, Sarah C. Rippe

Social Sciences

No abstract provided.


Redefining Zero? A Critical Review Of Definitions Of Zero Energy Buildings And Zero Carbon Homes, Emma Elizabeth Heffernan, Wei Pan, Xi Liang, Pieter De Wilde Jan 2013

Redefining Zero? A Critical Review Of Definitions Of Zero Energy Buildings And Zero Carbon Homes, Emma Elizabeth Heffernan, Wei Pan, Xi Liang, Pieter De Wilde

Faculty of Engineering and Information Sciences - Papers: Part A

From 2016 all new homes in the UK will be required, by law, to be 'zero carbon'. However, the detail of the Zero Carbon Homes standard is still being developed. Internationally there has been much debate on a definition for zero energy; though a consensus has yet to emerge. This paper presents an overview and synthesis of the literature on such definitions. Through a critical review, a series of options for the determination of a 'zero energy' or 'zero carbon' balance are revealed; the extent to which each option fully accounts for the energy consumed is also considered. The results …


Energy-Loss Rate Of A Fast Particle In Two-Dimensional Semiconductors With Rashba Spin-Orbit Coupling, Wei Feng, Asya Tawfiq, J.C Cao, Chao Zhang Jan 2013

Energy-Loss Rate Of A Fast Particle In Two-Dimensional Semiconductors With Rashba Spin-Orbit Coupling, Wei Feng, Asya Tawfiq, J.C Cao, Chao Zhang

Faculty of Engineering and Information Sciences - Papers: Part A

The energy-loss rate (ELR) of a charged particle in a two-dimensional semiconductor with Rashba spin-orbit coupling is studied. Our model takes into account of the temperature and density dependence of the electronic properties of the Rashba system. The energy and temperature dependence of the ELR are presented. It is found that a finite Rashba spin-orbit coupling offers a mechanism of tuning the mean scattering time in narrow-gap semiconductors. With a change of Rashba parameter of around 3 times, the mean scattering time can change by one to two orders of magnitude. © 2013 American Institute of Physics.


Energy Loss Rate Of A Charged Particle In Hgte/(Hgte, Cdte) Quantum Wells, Qinjun Chen, Yee Sin Ang, Xiaolin Wang, R A. Lewis, Chao Zhang Jan 2013

Energy Loss Rate Of A Charged Particle In Hgte/(Hgte, Cdte) Quantum Wells, Qinjun Chen, Yee Sin Ang, Xiaolin Wang, R A. Lewis, Chao Zhang

Faculty of Engineering and Information Sciences - Papers: Part A

The energy loss rate (ELR) of a charged particle in a HgTe/(HgTe, CdTe) quantum well is investigated. We consider scattering of a charged particle by the bulk insulating states in this type of topological insulator. It is found that the ELR characteristics due to the intraband excitation have a linear energy dependence while those due to interband excitation depend on the energy exponentially. An interesting quantitative result is that for a large range of the incident energy, the mean inelastic scattering rate is around a few terahertz.


On The Residual Energy Toughness Of Prestressed Concrete Sleepers In Railway Track Structures Subjected To Repeated Impact Loads, Sakdirat Kaewunruen, Alexander Remennikov Jan 2013

On The Residual Energy Toughness Of Prestressed Concrete Sleepers In Railway Track Structures Subjected To Repeated Impact Loads, Sakdirat Kaewunruen, Alexander Remennikov

Faculty of Engineering and Information Sciences - Papers: Part A

Installed as the crosstie beam support in railway track systems, the prestressed concrete sleepers (or railroad ties) are designed in order to carry and transfer the wheel loads from the rails to the ground. It is nowadays best known that railway tracks are subject to the impact loading conditions, which are attributable to the train operations with either wheel or rail abnormalities such as flat wheels, dipped rails, etc. These loads are of very high magnitude but short duration, as well as there exists the potential of repeated load experience during the design life of the prestressed concrete sleepers. These …


Cross-Section Calculations For Positron Scattering From Pyrimidine Over An Energy Range From 0.1 To 10000 Ev, A G. Sanz, M C. Fuss, F Blanco, Z Masin, J D. Gorfinkiel, R P. Mceachran, M J. Brunger, G Garcia Jan 2013

Cross-Section Calculations For Positron Scattering From Pyrimidine Over An Energy Range From 0.1 To 10000 Ev, A G. Sanz, M C. Fuss, F Blanco, Z Masin, J D. Gorfinkiel, R P. Mceachran, M J. Brunger, G Garcia

Faculty of Engineering and Information Sciences - Papers: Part A

We report a computational investigation of positron scattering by pyrimidine (C4H4N2) in the gas phase. Integral and differential cross sections have been calculated over a broad energy range by employing two distinct ab initio quantum scattering methods: the R-matrix method and a corrected form of the independent-atom representation, at low and high energies, respectively. Since pyrimidine is a strong polar molecule further dipole-induced excitations have been calculated in the framework of the first Born approximation. Good agreement is found between the different computational models and fair agreement is found with prior experimental results.