bluuebunny/crossref_metadata_2025 huggingface dataset:
Exploitation of thermophoresis effect to prevent re-deposition of expelled particulates in laser assisted surface cleaning
Authors: Sai Prasad M. B. , Dwivedi Tatsat , Patil Gautam C. , Padma Nilaya J. , Biswas D. J.
Published: October 2012

Evidence in the improvement of the cleaning efficiency in the case of laser assisted surface decontamination wherein the phenomenon of thermophoresis has been exploited to prevent re-deposition of minute particulates is reported. The thermophoresis effect was made to set in by providing an appropriate temperature gradient in the vicinity of the laser exposed surface. The effectiveness of thermophoresis towards improving the laser assisted cleaning efficiency of polished stainless steel (SS) surface contaminated with copper telluride metal chalcogenide nanoparticles has been studied and compared with that obtained under ambient and dynamic vacuum conditions.
Ultra-high hydrogen storage capacity of Li-decorated graphyne: A first-principles prediction
Authors: Zhang Hongyu , Zhao Mingwen , Bu Hongxia , He Xiujie , Zhang Meng , Zhao Lixia , Luo Youhua
Published: October 2012

Graphyne, consisting of sp- and sp2-hybridized carbon atoms, is a new member of carbon allotropes which has a natural porous structure. Here, we report our first-principles calculations on the possibility of Li-decorated graphyne as a hydrogen storage medium. We predict that Li-doping significantly enhances the hydrogen storage ability of graphyne compared to that of pristine graphyne, which can be attributed to the polarization of H2 molecules induced by the charge transfer from Li atoms to graphyne. The favorite H2 molecules adsorption configurations on a single side and on both sides of a Li-decorated graphyne layer are determined. When Li atoms are adsorbed on one side of graphyne, each Li can bind four H2 molecules, corresponding to a hydrogen storage capacity of 9.26 wt. %. The hydrogen storage capacity can be further improved to 15.15 wt. % as graphyne is decorated by Li atoms on both sides, with an optimal average binding energy of 0.226 eV/H2. The results show that the Li-decorated graphyne can serve as a high capacity hydrogen storage medium.
Halo formation and self-pinching of an electron beam undergoing the Weibel instability
Authors: Khudik Vladimir , Kaganovich Igor , Shvets Gennady
Published: October 2012

The collisionless Maxwellization of the energy distribution of an electron beam undergoing Weibel filamentation instability in a dense background plasma is demonstrated. While binary collisions between discrete charged particles are usually responsible for establishing the Maxwell-Boltzmann distribution (MBD) of non-equilibrium plasmas, we demonstrate that the same effect is achieved through collective collisions between multiple beam filaments. The final state of the filaments’ merger is a single pinched beam surrounded by a wide halo. An analytic model for the equilibrated beam is developed and used to estimate spatial profiles of the pinched beam and its halo, the temperature, and the magnetic field. Results of analytical theory agree well with those of particle-in-cell simulations. Deviations from the MBD are explained by incomplete Maxwellization of the electrons with high and low transverse energies.
Effects of mechanical contact stress on magnetic properties of ferromagnetic film
Authors: Lee Sungae , He Muyang , Yeo Chang-Dong , Abo Gavin , Hong Yang-Ki , Ho You Jeong
Published: October 2012

Mechanical and magnetic degradation of ferromagnetic films under contact stress was systematically investigated through novel experiments and analytical simulations. Permalloy (Ni80Fe20) film was deposited onto silicon substrate, and two different thicknesses of permalloy film (50 nm for sample A and 300 nm for sample B) were examined in this study. Magnetic properties were obtained from B-H loop tracer hysteresis measurement, while the mechanical properties (i.e., hardness and elastic modulus) were measured using nanoindentation techniques. It was observed that the 50 nm thick permalloy film showed weaker magnetic strength (lower coercivity and saturation magnetic flux values) and lower hardness than the 300 nm thick permalloy film. To apply mechanical contact stress on the permalloy film samples, nanoscratch experiments were performed using ramp and constant loading scratch profiles. Then, the resulting mechanical degradation (surface physical damage) of the two samples was determined from atomic force microscope measurements, and the corresponding magnetic degradation was analyzed using magnetic force microscope measurements. It was found that the magnetic degradation was more sensitive to the applied contact stress than the mechanical degradation. Comparing the two permalloy film samples, it was observed that the 50 nm thick permalloy film showed more magnetic degradation under the same contact stress, which could be attributed to its lower material strength.
Numerical simulation of nonlinear acoustic streaming in a resonator using gas-kinetic scheme
Authors: Feng Heying , Zhang Xiaoqing , Peng Yehui , Chen Huanxin
Published: October 2012

The acoustic streaming motion in a compressible air-filled two-dimensional cylindrical resonator driving by a piston is simulated by using the gas-kinetic scheme, and the effects of acoustic field intensity on the formation process of flow structure as well as streaming pattern are investigated numerically for the practical applications of high-intensity acoustic devices. Therefore, five cases with different excitation amplitudes are considered in simulation ranging from the linear to highly nonlinear regions. The validation of the developed model is verified by comparing the numerical results of streaming velocities with the theoretical ones for the linear case. The wave form of pressure and velocity and the transient flow field structure as well as the resulting streaming pattern are found to be strongly correlated to the excitation amplitude. Be observed for the linear case is a sine wave and a uniform of quasi-one-dimensional flow field as well as classical Rayleigh streaming. Periodic shock waves and strongly two-dimensional flow fields as well as the irregular acoustic streaming fields have been observed for the nonlinear cases. And some new physical phenomena have also been revealed for the highly nonlinear case, and these facts are that the wave form will deviate from typical “shock wave”-type toward a more distorted type, and at the same time, the two-dimensional transient flow fields are characterized by the changing flow direction and circulatory flow pattern, which are all correlated to a turbulent streaming with various scales of irregular and unsteady vortices throughout the resonator. Detailed explanations are provided for these nonlinear phenomena, and a critical Reynolds number for the transition to turbulence is also numerically obtained which is consistent with the experiment result from the previous publication. The present work has demonstrated that the gas-kinetic scheme is capable of resolving large Reynolds number of nonlinear acoustic problems with no any restriction on the nonlinearity level.
Pyramidal dislocation induced strain relaxation in hexagonal structured InGaN/AlGaN/GaN multilayer
Authors: Yan P. F. , Du K. , Sui M. L.
Published: October 2012

Due to the special dislocation slip systems in hexagonal lattice, dislocation dominated deformations in hexagonal structured multilayers are significantly different from that in cubic structured systems. In this work, we have studied the strain relaxation mechanism in hexagonal structured InGaN/AlGaN/GaN multilayers with transmission electron microscopy. Due to lattice mismatch, the strain relaxation was found initiated with the formation of pyramidal dislocations. Such dislocations locally lie at only one preferential slip direction in the hexagonal lattice. This preferential slip causes a shear stress along the basal planes and consequently leads to dissociation of pyramidal dislocations and operation of the basal plane slip system. The compressive InGaN layers and “weak” AlGaN/InGaN interfaces stimulate the dissociation of pyramidal dislocations at the interfaces. These results enhance the understanding of interactions between dislocations and layer interfaces and shed new lights on deformation mechanism in hexagonal-lattice multilayers.
First-principles study of electronic structure and magnetic properties of Cu-doped CeO2
Authors: Li Feng , Zhang Chang-wen , Zhao Mingwen
Published: October 2012

We performed first-principles calculations within density-functional theory to study the origin of the magnetism in Cu-doped CeO2. We show that the electron spin-polarization and the magnetic coupling are sensitive to the defect structures in Cu-doped CeO2. The substitution of a Cu atom for a Ce atom (CuCe) induces a local magnetic moment of 3.00 μB around per impurity, but the magnetic coupling between local magnetic moments is very weak. The defect complex consisting of a CuCe and a nearest-neighbor oxygen vacancy (VO) has low formation energy and thus high plausibility in Cu-doped CeO2. Although the local magnetic moment triggered by the CuCe-VO complex is only 1.00 μB per complex, strong ferromagnetic coupling between the defect complexes is achieved which can be attributed to a magnetic coupling chain formed by the strong p-d interaction between Cu and host O atoms.
Investigation of the light emission properties and carrier dynamics in dual-wavelength InGaN/GaN multiple-quantum well light emitting diodes
Authors: Liu Lei , Wang Lei , Liu Ningyang , Yang Wei , Li Ding , Chen Weihua , Chuan Feng Zhe , Lee Yueh-Chien , Ferguson Ian , Hu Xiaodong
Published: October 2012

Three dual-wavelength InGaN/GaN multiple quantum well (MQW) light emitting diodes (LEDs) with increasing indium content are grown by metal-organic chemical vapor deposition, which contain six periods of low-In-content MQWs and two periods of high-In-content MQWs. For the low-In-content MQWs of three studied samples, their internal quantum efficiency (IQE) shows a rising trend as the emission wavelength increases from 406 nm to 430 nm due to the suppression of carriers escape from the wells to the barriers. However, for the high-In-content MQWs, the sample IQE falls rapidly with a further increase of emission wavelength from 496 nm to 575 nm. Theoretical calculation reveals that the electron-hole wave function overlap in the high-In-content MQWs is reduced because of an increase in the internal polarization field as indium content is increased. In addition, time-resolved photoluminescence decay curves show that the carriers generated in the low-In-content MQWs can be effectively transferred to the high-In-content part through the reabsorption process. However, the transfer time gradually becomes longer as emission wavelength increases, which means a reduction of carrier transfer rate between the different indium content MQWs. Furthermore, nonradiative recombination is enhanced in the high-In-content MQWs with longer emission wavelength due to the decline of crystal quality. Therefore, the fast drop of IQE for high-In-content MQWs can be attributed to the increase of the internal polarization field, the decrease of carrier transfer efficiency, and the enhanced nonradiative recombination. This research has a certain guiding value for an understanding of the recombination mechanism in the InGaN/GaN MQWs and for achieving high quality multiple-wavelength LEDs with better performance.
Half-metallic ferromagnetism in (CrN)1/(GaN)1 (001) and (VN)1/(InN)1 (001) superlattices
Authors: Belmiloud N. , Zaoui A. , Ferhat M.
Published: October 2012

Density functional theory calculations are performed to study the structural, electronic, and magnetic properties of zinc blende (CrN)1/(GaN)1 and (VN)1/(InN)1 superlattice in the (001) direction. Results show that (CrN)1/(GaN)1 and (VN)1/(InN)1 superlattice are half-metallic ferromagnets, with respectively a total magnetic moment of 6 μB and 4 μB. We also show that ferromagnetism comes essentially from the d orbitals of the Cr and V atoms, and the half metallic character is the fingerprint of the p-d hybridization of N and Cr(V) atoms.
The positive ion temperature effect in magnetized electronegative plasma sheath with two species of positive ions
Authors: Shaw A. K. , Kar S. , Goswami K. S.
Published: October 2012

The properties of a magnetized multi-component (two species of positive ions, negative ions and electrons) plasma sheath with finite positive ion temperature are studied. By using three fluid hydrodynamic model and some dimensionless variables, the ion (both lighter and heavier positive ions, and negative ions) densities, the ion (only for positive ions) velocities, and electric potential inside the sheath are investigated. In addition, the absence and presence of magnetic field and the orientation of magnetic field are considered. It is noticed that, with increase of positive ion temperature, the lighter positive ion density peaks increase only at the sheath edge and shift towards the sheath edge for both absence and presence of magnetic field. For heavier positive ions, in the absence of magnetic field, the density peaks increase at the sheath edge. But in the presence of magnetic field, the density fluctuations increase at the sheath edge. For both the cases, the density peaks shift towards the sheath edge.
Spatio-temporal evolution and breaking of double layers: A description using Lagrangian hydrodynamics
Authors: Kaw Predhiman , Sengupta Sudip , Singh Verma Prabal
Published: October 2012

The nonlinear development and collapse (breaking) of double layers in the long scale length limit is well described by equations for the cold ion fluid with quasineutrality. It is shown that electron dynamics is responsible for giving an “equation of state” with negative ratio of specific heats to this fluid. Introducing a transformation for the density variable, the governing equation for the transformed quantity in terms of Lagrange variables turns out exactly to be a linear partial differential equation. This equation has been analyzed in various limits of interest. Nonlinear development of double layers with a sinusoidal initial disturbance and collapse of double layers with an initial perturbation in the form of a density void are analytically investigated.
Topological insulator Bi2Te3 films synthesized by metal organic chemical vapor deposition
Authors: Cao Helin , Venkatasubramanian Rama , Liu Chang , Pierce Jonathan , Yang Haoran , Zahid Hasan M. , Wu Yue , Chen Yong P.
Published: October 2012

Topological insulator (TI) materials such as Bi2Te3 and Bi2Se3 have attracted strong recent interests. Large scale, high quality TI thin films are important for developing TI-based device applications. In this work, structural and electronic properties of Bi2Te3 thin films deposited by metal organic chemical vapor deposition (MOCVD) on GaAs (001) substrates were characterized via x-ray diffraction (XRD), Raman spectroscopy, angle-resolved photoemission spectroscopy (ARPES), and electronic transport measurements. The characteristic topological surface states with a single Dirac cone have been clearly revealed in the electronic band structure measured by ARPES, confirming the TI nature of the MOCVD Bi2Te3 films. Resistivity and Hall effect measurements have demonstrated relatively high bulk carrier mobility of ∼350 cm2/Vs at 300 K and ∼7400 cm2/Vs at 15 K. We have also measured the Seebeck coefficient of the films. Our demonstration of high quality topological insulator films grown by a simple and scalable method is of interests for both fundamental research and practical applications of thermoelectric and TI materials.
Formation of SiGe nanocrystals embedded in Al2O3 for the application of write-once-read-many-times memory
Authors: Wu Min-Lin , Wu Yung-Hsien , Lin Chia-Chun , Chen Lun-Lun
Published: October 2012

The structure of SiGe nanocrystals embedded in Al2O3 formed by sequential deposition of Al2O3/Si/Ge/Al2O3 and a subsequent annealing was confirmed by transmission electron microscopy and energy dispersive spectroscopy (EDS), and its application for write-once-read-many-times (WORM) memory devices was explored in this study. By applying a −10 V pulse for 1 s, a large amount of holes injected from Si substrate are stored in the nanocrystals and consequently, the current at +1.5 V increases by a factor of 104 as compared to that of the initial state. Even with a smaller −5 V pulse for 1 μs, a sufficiently large current ratio of 36 can still be obtained, verifying the low power operation. Since holes are stored in nanocrystals which are isolated from Si substrate by Al2O3 with good integrity and correspond to a large valence band offset with respect to Al2O3, desirable read endurance up to 105 cycles and excellent retention over 100 yr are achieved. Combining these promising characteristics, WORM memory devices are appropriate for high-performance archival storage applications.
Magnetocaloric properties of La(Fe,Si)13-based material and its hydride prepared by industrial mischmetal
Authors: Bao L. F. , Hu F. X. , Chen L. , Wang J. , Sun J. R. , Shen B. G.
Published: October 2012

Here, we choose La-Ce-Pr-Nd industrial mischmetal with low purity as raw material to prepare La(Fe,Si)13-based magnetocaloric material and its hydride. It is demonstrated that the introduced impurities in the starting materials do not impair the formation of NaZn13-type structure. The multi-replacement of La by magnetic atoms Ce,Pr,Nd enhances Curie temperature TC while keeps the strong itinerant electron metamagnetic behavior. As a result, good magnetocaloric (MCE) properties appear in La0.7(Ce,Pr,Nd)0.3Fe11.6Si1.4 (LRFS) compound. The incorporation of interstitial H atom remarkably reduces hysteresis loss while increases TC to 314 K. The effective refrigeration capacity after deducting hysteresis can be increased by ∼128% upon H doping.
Effect of radical fluorination on mono- and bi-layer graphene in Ar/F2 plasma
Authors: Tahara K. , Iwasaki T. , Matsutani A. , Hatano M.
Published: October 2012

Fluorinated graphene has the possibility to achieve unique properties and functions in graphene. We propose a highly controlled fluorination method utilizing fluorine radicals in Ar/F2 plasma. To suppress ion bombardments and improve the reaction with fluorine radicals on graphene, the substrate was placed “face down” in the plasma chamber. Although monolayer graphene was more reactive than bilayer, fluorination of bilayer reached the level of ID/IG ∼ 0.5 in Raman D peak intensity at 532 nm excitation. Annealing fluorinated samples proved reversibility of radical fluorination for both mono- and bi-layer graphenes. X-ray photoelectron spectroscopy showed the existence of carbon-fluorine bonding.
Opto-fluidic velocimetry using liquid crystal microfluidics
Authors: Sengupta Anupam , Herminghaus Stephan , Bahr Christian
Published: October 2012

The coupling between flow and orientation of nematic liquid crystal molecules has been utilized to devise a non-intrusive opto-fluidic velocimetry technique on a microfluidic platform. The flow-induced reorientation of the liquid crystal molecules in a diverging channel possessing homeotropic surface anchoring produced distinct birefringent domains, directly observable through their interference colors, which are characteristic to the local flow velocity. The flow-induced effective birefringence was characterized using polarizing optical microscopy, confocal fluorescence polarizing microscopy, and particle tracking methods.
Parallel-leaky capacitance equivalent circuit model for MgO magnetic tunnel junctions
Authors: Sahadevan Ajeesh M. , Gopinadhan Kalon , Bhatia Charanjit S. , Yang Hyunsoo
Published: October 2012

The capacitance of MgO based magnetic tunnel junctions (MTJs) has been observed to be magnetic field dependent. We propose an equivalent circuit for the MTJs with a parallel-leaky capacitance (Cl) across the series combination of geometric and interfacial capacitance. The analysis of junctions with different tunneling magnetoresistance (TMR) values suggests higher Cl for low TMR junctions. Using Cole-Cole plots, the capacitive nature of MTJs is manifested. Fitting with Maxwell-Wagner capacitance model validates the RC parallel network model for MTJs and the extracted field dependent parameters match with the experimental values.
Mobilities of O2+ and O2− ions in femtosecond laser filaments in air
Authors: Polynkin Pavel
Published: October 2012

The operation of the capacitive plasma probe commonly used for measurements of plasma density in laser filaments and sparks in gases is analyzed. The probe is employed to measure absolute mobilities of O2+ and O2− ions produced through femtosecond laser filamentation in air.
Localized surface plasmon resonances in highly doped semiconductors nanostructures
Authors: N'Tsame Guilengui V. , Cerutti L. , Rodriguez J.-B. , Tournié E. , Taliercio T.
Published: October 2012

We demonstrate the occurrence of localized surface plasmon resonances (LSPRs) in periodic arrays of highly doped/un-doped InAsSb/GaSb semiconductor nanostructures, where highly doped InAsSb is degenerated and exhibits a metallic behavior while being lattice-matched onto GaSb. Reflectance spectroscopy allows investigating the impact of the geometrical and physical properties of both InAsSb and GaSb materials on the LSPR. Our results show that these InAsSb/GaSb nanostructures form the building blocks of metal-free, all-semiconductor infrared plasmonic devices.
Polarization dependant scattering as a tool to retrieve the buried phase information of surface plasmon polaritons
Authors: Crosbie S. , McClean É. , Zerulla D.
Published: October 2012

We report on an experimental and theoretical study demonstrating that the phase information of a surface plasmon polariton (SPP) can be retrieved by investigating the cross polarized scattered components in the SPP reflection channel. The method does not require traditional interferometric techniques, optical heterodyning, or polarimetry, instead the method is self referencing. Studies are performed for different excitation wavelengths (561 nm and 795 nm), providing an alternative access route to phase information for sensing applications while also offering a deeper understanding of the scattering behavior of SPPs.
Ultrasmall radial polarizer array based on patterned plasmonic nanoslits
Authors: Iwami Kentaro , Ishii Miho , Kuramochi Yuzuru , Ida Kenichi , Umeda Norihiro
Published: October 2012

We developed an ultrasmall radial or azimuthal polarization converter of size ranged from 10 to 100 μm. The converter consists of a half-wave plate divided into four quadrants, each of which is made of periodic gold nanoslits at different orientations in steps of 45°. The converter and its array were fabricated and followed by an evaluation with the Sénarmont method and the polarization microscopy. Due to the giant birefringence of the gold nanoslits, each slit segment achieved 180° retardation at the wavelength of 633 nm, and the conversion from linear to radial polarization was demonstrated.
Soft Spaces as Vehicles for Neoliberal Transformations of Strategic Spatial Planning?
Authors: Olesen Kristian
Published: October 2012

With this paper I analyse how policy agendas are being shaped and reshaped in new soft spaces emerging in Danish spatial planning at subnational scales, and how policy making in these soft spaces seeks to influence formal planning arenas. The paper demonstrates how the new soft planning spaces in Danish spatial planning primarily are concerned with promoting policy agendas centred on economic development, whilst doing limited work in filling in the gaps between formal scales of planning, as envisaged in the planning literature. Instead, soft spaces seem to add to the increasing pressures on statutory spatial planning, being used as vehicles for neoliberal transformations of strategic spatial planning. I therefore argue for a need to maintain a critical stance towards the emergence of soft spaces in spatial planning.
Divergent Pathways of Development: A Comparative Case Study of Human Well-Being in Two Thai Provinces
Authors: Parks Sarah
Published: October 2012

Over the last two decades there has been a growing interest in shifting the political focus from gross domestic product as an indicator of well-being to more pluralistic concepts. Correspondingly, approaches to development have also evolved. A case study of two neighboring Thai provinces, Samut Sakhon and Samut Songkhram, provides a means to examine divergent development pathways and the resulting differences in well-being. Samut Sakhon was influenced by traditional economic forces. By contrast, the United Nations Development Programme cited Samut Songkhram as a “showcase of the sufficiency economy”, although the extent to which the sufficiency economy philosophy was deliberately applied is unclear. Today, the gross provincial product is much higher in Samut Sakhon, but Samut Songkhram ranks higher on the human achievement index (HAI). In comparison with traditional economic indicators, the HAI provides a more realistic depiction of the provinces; however, the index has shortcomings in regards to social and environmental issues.
The Role of Cluster Policy on Leadership: Evidence from Two Pôles De Compétitivité
Authors: Menu Sabine
Published: October 2012

Since the late 1990s researchers have looked at cluster policies, highlighting multilevel governance processes and the resulting complexity for both public and private actors as well as measuring the impact of these policies on firms. From an institutional perspective I point out that this policy development calls for the study of the impact on leadership: have cluster policies played any role in leadership emergence in clusters? I take the launch of the Pôles de compétitivité in 2005 as an illustration. I first review the literature and point out the gaps in dealing with (cluster) leadership and the policy context. Second, I present comparative and empirical results of two clusters located in Brittany, France. Third, by discussing these results, I show the implications both for the study of French dirigisme (an interventionist and directive policy style) and for current research on cluster policies by outlining the emergence, dynamics, and limits of the leadership process.
Agronomic and economic evaluation of irrigation strategies on cotton lint yield in Australia
Authors: Cammarano Davide , Payero José , Basso Bruno , Wilkens Paul , Grace Peter
Published: October 2012

Cotton is one of the most important irrigated crops in subtropical Australia. In recent years, cotton production has been severely affected by the worst drought in recorded history, with the 2007–08 growing season recording the lowest average cotton yield in 30 years. The use of a crop simulation model to simulate the long-term temporal distribution of cotton yields under different levels of irrigation and the marginal value for each unit of water applied is important in determining the economic feasibility of current irrigation practices. The objectives of this study were to: (i) evaluate the CROPGRO-Cotton simulation model for studying crop growth under deficit irrigation scenarios across ten locations in New South Wales (NSW) and Queensland (Qld); (ii) evaluate agronomic and economic responses to water inputs across the ten locations; and (iii) determine the economically optimal irrigation level. The CROPGRO-Cotton simulation model was evaluated using 2 years of experimental data collected at Kingsthorpe, Qld The model was further evaluated using data from nine locations between northern NSW and southern Qld. Long-term simulations were based on the prevalent furrow-irrigation practice of refilling the soil profile when the plant-available soil water content is <50%. The model closely estimated lint yield for all locations evaluated. Our results showed that the amounts of water needed to maximise profit and maximise yield are different, which has economic and environmental implications. Irrigation needed to maximise profits varied with both agronomic and economic factors, which can be quite variable with season and location. Therefore, better tools and information that consider the agronomic and economic implications of irrigation decisions need to be developed and made available to growers.
Linking complex forest fuel structure and fire behaviour at fine scales
Authors: Loudermilk E. Louise , O'Brien Joseph J. , Mitchell Robert J. , Cropper Wendell P. , Hiers J. Kevin , Grunwald Sabine , Grego John , Fernandez-Diaz Juan C.
Published: October 2012

Improved fire management of savannas and open woodlands requires better understanding of the fundamental connection between fuel heterogeneity, variation in fire behaviour and the influence of fire variation on vegetation feedbacks. In this study, we introduce a novel approach to predicting fire behaviour at the submetre scale, including measurements of forest understorey fuels using ground-based LIDAR (light detection and ranging) coupled with infrared thermography for recording precise fire temperatures. We used ensemble classification and regression trees to examine the relationships between fuel characteristics and fire temperature dynamics. Fire behaviour was best predicted by characterising fuelbed heterogeneity and continuity across multiple plots of similar fire intensity, where impacts from plot-to-plot variation in fuel, fire and weather did not overwhelm the effects of fuels. The individual plot-level results revealed the significance of specific fuel types (e.g. bare soil, pine leaf litter) as well as the spatial configuration of fire. This was the first known study to link the importance of fuelbed continuity and the heterogeneity associated with fuel types to fire behaviour at metre to submetre scales and provides the next step in understanding the complex responses of vegetation to fire behaviour.
Chemical and dispersal characteristics of particulate emissions from forest fires in Siberia
Authors: Samsonov Y. N. , Ivanov V. A. , McRae D. J. , Baker S. P.
Published: October 2012

Approximately 20 experimental fires were conducted on forest plots of 1–4 ha each in 2000–07 in two types of boreal forests in central Siberia, and 18 on 6 × 12-m plots in 2008–10. These experiments were designed to mimic wildfires under similar burning conditions. The fires were conducted in prescribed conditions including full documentation on pre-fire weather, pre-fire and post-fire forest fuels, fire intensities, and other biological, physical and chemical parameters. The amount of particulate matter emitted during a typical fire averaged 0.6 t ha–1 and ranged within 0.2–1.0 t ha–1 depending on burning conditions. Particulates accounted for ~1–7% of the total mass of the consumed biomass during a typical forest fire (10–30 t ha–1 based on our data from 2000–07). Most of the particulate matter consists of organic substances, 77% on average, with a range of 70–90%. Elemental carbon averaged 8%, with a range of 2–18%. Trace element compositions and amounts of particulates indicate that there was no actual difference in the element emissions sampled from the fires conducted in the two forest types (6–8% in larch forest and 8% in pine forest). Most of the particulate matter, 90–95%, consists of submicrometre and near-micrometre particles ~0.1–5 μm in diameter.
Identifying location and causality of fire ignition hotspots in a Mediterranean region
Authors: Gonzalez-Olabarria José Ramón , Brotons Lluis , Gritten David , Tudela Antoni , Teres José Angel
Published: October 2012

Fire ignitions tend to be spatially aggregated depending on their causality. In highly populated regions, such as the northern Mediterranean basin, human activities are the main cause of ignitions. The ability to locate zones with an intense and recurrent history of fire occurrence and identify their specific cause can be helpful in the implementation of measures to reduce the problem. In the present study, kernel methods, non-parametric statistical methods for estimating the spatial distribution of probabilities of point-based data, are used to define ignition hotspots based on historical records of fire ignitions in Catalonia for the period 1995–2006. Comparison of the cause of the ignitions within the area of the hotspots enabled analysis of the relation between the cause of the ignitions and the occurrence of hotspots. The results obtained highlighted that the activity of arsonists showed strong spatial clustering, with the share of intentionally caused ignitions within the hotspot areas accounting for 60.1% of the fires, whereas for the whole of Catalonia they only represented 24.3%. The findings of the study provide an opportunity to optimally allocate law-enforcement and educational resources within hotspot areas.
Householder decision-making under imminent wildfire threat: stay and defend or leave?
Authors: McLennan Jim , Elliott Glenn , Omodei Mary
Published: October 2012

The study examined aspects of decision-making that distinguish between those who stay and defend their property and those who leave for an assumed safer location when a community comes under imminent threat from a severe wildfire. The data were obtained from field interviews with 49 survivors of the Murrindindi wildfire (Victoria, Australia, 7 February 2009) in which 38 people perished and that destroyed the small township of Marysville. Uncertainty about the level of threat was a major feature of the decision-making context in the period immediately preceding the impact of the fire. The majority of those who stayed and defended did so because they were committed to this plan of action. For most of those who left, the action of leaving was triggered by realisation of the severe threat posed by the intensity or location of the fire.
Humanities: the unexpected success story of the twenty-first century
Authors: Davis Virginia
Published: October 2012

Humanities within universities faced challenges in the latter half of the twentieth century as their value in the modern world was questioned. This paper argues that there is strong potential for the humanities to thrive in the twenty-first century university sector. It outlines some
of the managerial implications necessary to ensure that this potential is delivered. Study of humanities provides an education offering skills to tackle the problems facing the twenty-first century world. The importance of clear communication of the value of the humanities to different constituencies,
especially policy makers, institutional governing bodies and prospective students is emphasised.
EARLY SCIENCE WITH THE KOREAN VLBI NETWORK: THE QCAL-1 43 GHz CALIBRATOR SURVEY
Authors: Petrov Leonid , Lee Sang-Sung , Kim Jongsoo , Jung Taehyun , Oh Junghwan , Sohn Bong Won , Byun Do-Young , Chung Moon-Hee , Je Do-Heung , Wi Seog-Oh , Song Min-Gyu , Kang Jiman , Han Seog-Tae , Lee Jung-Won , Kim Bong Gyu , Chung Hyunsoo , Kim Hyun-Goo
Published: October 2012

This paper presents the catalog of correlated flux densities in three ranges of baseline projection lengths of 637 sources from a 43 GHz (Q band) survey observed with the Korean VLBI Network. Of them, 14 objects used as calibrators were previously observed, but 623 sources have not been observed before in the Q band with very long baseline interferometry (VLBI). The goal of this work in the early science phase of the new VLBI array is twofold: to evaluate the performance of the new instrument that operates in a frequency range of 22–129 GHz and to build a list of objects that can be used as targets and as calibrators. We have observed the list of 799 target sources with declinations down to −40°. Among them, 724 were observed before with VLBI at 22 GHz and had correlated flux densities greater than 200 mJy. The overall detection rate is 78%. The detection limit, defined as the minimum flux density for a source to be detected with 90% probability in a single observation, was in the range of 115–180 mJy depending on declination. However, some sources as weak as 70 mJy have been detected. Of 623 detected sources, 33 objects are detected for the first time in VLBI mode. We determined their coordinates with a median formal uncertainty of 20 mas. The results of this work set the basis for future efforts to build the complete flux-limited sample of extragalactic sources at frequencies of 22 GHz and higher at 3/4 of the celestial sphere.
Multiferroic properties of Ba2+ and Gd3+ co-doped bismuth ferrite: magnetic, ferroelectric and impedance spectroscopic analysis
Authors: Das Rajasree , Sarkar Tanushree , Mandal K
Published: October 2012

Enhanced magnetoelectric coupling is observed in bismuth ferrite samples, co-doped with non-magnetic Ba and magnetic Gd ions replacing Bi and Fe, respectively. Distortion in Fe–O octahedra has a significant effect on the magnetic properties of the samples. Ferromagnetic signature is found to increase significantly in the co-doped samples with respect to the only-Gd-doped sample both at 80 and 300 K. The co-doped samples show enhanced electric polarization as well as the highest resistivity at room temperature, which might be due to the reduction in the leakage current and oxygen vacancy in the compositions. An interesting correlation between the antiferromagnetic Néel temperature (T
N) of bismuth ferrite and the temperature-dependent dielectric constant is observed in all samples. Bi0.9Ba0.1Fe0.95Gd0.05O3 ceramic possesses maximum coupling between electric dipole and magnetic dipole with an estimated magnetodielectric effect MD ([ε
r(H) − ε
r (0)]/ε
r (0)) ∼ 380 at an applied field of 6 kOe. Impedance spectroscopy in the frequency range 40–107 Hz and temperature within 30–300 °C suggests that grain relaxation is dominant in the samples. Electrical parameters (such as capacitance and resistance) of the grains are determined using the real and imaginary parts of impedance (Z′ and Z″) and the electrical modulus (M′ and M″) plot. The results of electrical conductivity indicate a correlated barrier hopping conduction mechanism in the samples.
Strain-modulated magnetocapacitance of vertical ferroelectric–ferromagnetic nanocomposite heteroepitaxial films
Authors: Wu Huaping , Xu Bin , Liu Aiping , Chai Guozhong
Published: October 2012

The strain-mediated magnetocapacitance (MC) of 1–3-type vertical ferroelectric–ferromagnetic nanocomposite films epitaxially grown on different cubic substrates is theoretically calculated using the nonlinear thermodynamic theory combined with elastic theory. The dependences of relative dielectric constant and strain sensitivity of permittivity for the ferroelectric film on the in-plane and out-of-plane misfit strains are obtained. Our results show that the MC effect strongly depends on the in-plane misfit strain and ferromagnetic volume fraction in the nanocomposite films. The calculated MC for the BaTiO3–CoFe2O4 nanocomposite film grown on the SrTiO3 substrate is consistent with the experimental result. Furthermore, a giant MC, which is enhanced by 1–2 orders of magnitude than those reported in experiments, can be obtained for the BaTiO3–CoFe2O4 system grown on the MgO substrate near the transition from the aa-phase to the r-phase. Our result provides a new method for the design of multiferroic nanocomposites with colossal MC effect by optimizing the ferromagnetic phase and substrate types to realize their applications in magnetic-field-controlled electric devices, such as magneto-oscillators, magnetovaractors and magnetoelectric sensors.
An ab initio molecular dynamics study: liquid-Al/solid-TiB2 interfacial structure during heterogeneous nucleation
Authors: Zhang H L , Han Y F , Dai Y B , Wang J , Sun B D
Published: October 2012

The structural properties of the liquid/solid interface between a TiB2 substrate and Al melts during a nucleation process are investigated using ab initio molecular dynamics simulation at 2 K undercoolings. Different ordered structures are formed on the interfaces with different terminations of TiB2 (0 0 0 1) surface, which determines the nucleant potency of TiB2 particles. It is found that five Al layers stacking like fcc-Al (1 1 1) planes on the Ti-terminated surface naturally extend into the liquid region, which is helpful in effective heterogeneous nucleation. In contrast, the heterogeneous nucleation of α-Al on the B-terminated surface is frustrated by both the AlB2-like structure formed within the first Al layer and the area with sparse Al atoms between the localized Al layer and liquid regions. An evaluation factor based on the Z-directional projection is proposed to quantitatively characterize the in-plane ordering, which could draw a clear boundary between the quasi-solid region and the liquid phase in the liquid/solid interface system.
Preparation and thermoelectric properties of sintered n-type K8M8Sn38 (M = Al, Ga and In) with the type-I clathrate structure
Authors: Hayashi M , Kishimoto K , Akai K , Asada H , Kishio K , Koyanagi T
Published: October 2012

The maximum dimensionless figures-of-merit ZT
max were 0.13 at 410 K for K8Al8Sn38, 0.25 at 440 K for K8Ga8Sn38 and 0.21 at 420 K for K8In8Sn38, where their room temperature (RT) mobilities were 4.1 cm2 V−1 s−1, 31.0 cm2 V−1 s−1 and 9.8 cm2 V−1 s−1, respectively, their RT effective masses were 4.3, 1.8 and 3.2 m
e, respectively, and their RT lattice thermal conductivities were 12 mW cm−1 K−1, 14 mW cm−1 K−1 and 13 mW cm−1 K−1, respectively. The analysis of the measured transport properties suggested that these samples suffered from grain boundary scattering at lower temperatures and from alloy disorder scattering and acoustic phonon scattering at higher temperatures. In particular, such a low mobility of the K8Al8Sn38 sample was considered to be caused by strong alloy disorder scattering. Band structure calculations demonstrated that, in order of K8Ga8Sn38, K8In8Sn38 and K8Al8Sn38, their conduction band edges were sharper and their band structures near the gaps were more similar to that of K8Sn46. These features were well consistent with their measured effective masses and mobilities.
Diffusion of Si and C atoms on and between graphene layers
Authors: Xian Lede , Chou M Y
Published: October 2012

The growth of epitaxial graphene on SiC surfaces is accompanied by the evaporation of Si atoms during the growth process. The continuous loss of Si atoms takes place even after the surface graphene layers are formed. Understanding the atomic transport process involved is critical in establishing a growth mechanism to model and control the process. Using density functional theory, we have calculated the potential energy variation and studied the diffusion of Si and C atoms on a single layer of graphene and between graphene sheets. Our results show that Si atoms can move almost freely on graphene and between graphene layers, while C atoms have much larger diffusion barriers. This work provides a detailed description of the energetics of relevant processes in the growth of epitaxial graphene on SiC surfaces.
On a class of hereditary crossed-product orders
Authors: Kauta John
Published: October 2012

In this brief note, we revisit a class of crossed-product orders over discrete valuation rings introduced by D. E. Haile. We give simple but useful criteria, which involve only the two-cocycle associated with a given crossed-product order, for determining whether such an order is a hereditary order or a maximal order.
On the existence of strong travelling wave profiles to 2×2 systems of viscous conservation laws
Authors: Ohwa Hiroki
Published: October 2012

We consider strong travelling wave profiles for a class of

2
×
2

2\times 2

viscous conservation laws. Our main assumption is that the product of nondiagonal elements within the Fŕechet derivative (Jacobian) of the flux is nonnegative. By using the regularization method improved by the author, we prove the existence of strong travelling wave profiles for those systems.
Prologue
Authors: Gooptu Suparna
Published: October 2012

Cornelia Sorabji was the first woman to study law in Oxford, the second Indian woman barrister, and among the first Indian women to practise at the Calcutta High Court, to be appointed to a senior bureaucratic office under the British government, and to protect the interests of the purdahnashins. To strike a balance between her pioneering role as a lawyer and her individualism, and political and social conservatism, a personality like Cornelia needed supportive emotional anchors in her life, with whom she could share her ‘unconventionality’ and consequent isolation. Her personal relationship with Harrison Falkner Blair and Elena Rathbone may make one ponder as to why she chose to remain single, although she had a romantic idea of marriage and thought it to be a source of strength and sustenance. The irony of Cornelia's life was that she failed to see any legitimacy in the democratic and nationalist aspirations of the Indian people.
The Oxford Days: 1889–93
Authors: Gooptu Suparna
Published: October 2012

This chapter first addresses the entry of women into higher education and professions in England. It specifically deals with Cornelia Sorabji in Somerville Hall, Oxford. When she joined Somerville Hall, she was not sure what course she would pursue. Her Oxford experience proved to be crucial in making her what she was to become. She also did become the first woman to study for the BCL at Oxford, a major landmark in the history of women's entry into higher education. Oxford treated Cornelia as an ‘exception’. She had the privilege of being inducted into the Oxford elite circle from her initial days at the university, and she took pride in this fact. The patronage that Cornelia received at Oxford was largely because of its multiple involvements with the sustenance of the Empire. Moreover, her response to the male bias in Oxford is revealed. Additionally, it covers the new Toryism, authoritarian liberalism and faith in the Empire. Once Cornelia had completed her studies in Oxford, life appeared to be more difficult than she expected.
In Colonial Bureaucracy
Authors: Gooptu Suparna
Published: October 2012

This chapter first provides a discussion on legal help to the purdahnashins and extensions of the authority of the Empire. Cornelia Sorabji's duties as the lady legal adviser to the court of wards comprised legal as well as non-legal functions. An important implication of her role as an intermediary between the government and her wards was the extension of imperial authority to the court of wards' estates. It also addresses Cornelia and the purdahnashins of Bengal. It then deals with Cornelia's imagined sisterhood of purdahnashins. Working with the purdahnashins, she developed a deep admiration for them. The English women and the purdahnashins of Bengal are reported. In general, Cornelia's work in colonial bureaucracy clearly reveals how, being a pioneer, she too had to convince the authorities of the value and worth of her work, and fight for its proper recognition, in vain.
At the Calcutta High Court
Authors: Gooptu Suparna
Published: October 2012

This chapter begins by considering Cornelia Sorabji as she fights male bias in the legal profession. She became a victim of the reluctance of the Calcutta Bar to enlarge its membership, though in theory, it was a time when the Bar, hitherto based on the exclusive privileges of a few, was undergoing a crucial transformation. Her determination to undo the predominant gender discrimination in society and pave the way for the next generation of women, for a new professional life, encouraged her to keep her spirits high even in her most despondent moments. In the profession, Cornelia also had to fight the ‘old boys' network’ among British and Indian men, which largely determined success in the legal profession. Moreover, the issue of professional morality is explained. Furthermore, her sources of emotional sustenance in professional life are shown.