bluuebunny/crossref_metadata_2025 huggingface dataset:
SiO2-assisted synthesis of layered MoS2/reduced graphene oxide intercalation composites as high performance anode materials for Li-ion batteries
Authors: Tronganh Nguyen , Yang Yaqing , Chen Fang , Lu Mengna , Jiang Yong , Gao Yang , Cheng Lingli , Jiao Zheng
Published: August 2016

Layered MoS2/reduced graphene oxide (MoS2/rGO) intercalation composites are synthesized via a SiO2-assisted hydrothermal method.
Promoting crystalline grain growth and healing pinholes by water vapor modulated post-annealing for enhancing the efficiency of planar perovskite solar cells
Authors: Ge Qian-Qing , Ding Jie , Liu Jie , Ma Jing-Yuan , Chen Yao-Xuan , Gao Xiao-Xin , Wan Li-Jun , Hu Jin-Song
Published: August 2016

Water vapor modulated post-annealing is a reproducible and easily-scalable method to promote the grain growth and heal the pinholes for efficient PSCs.
Eliminating fine-grained layers in Cu(In,Ga)(S,Se)2 thin films for solution-processed high efficiency solar cells
Authors: Zhao Dandan , Fan Qingmiao , Tian Qingwen , Zhou Zhengji , Meng Yuena , Kou Dongxing , Zhou Wenhui , Wu Sixin
Published: August 2016

An improved route to fabricate Cu(In,Ga)(S,Se)2 thin films is proposed for obtaining a large-grained layer throughout the films, which greatly facilitates the improvement of the performance of Cu(In,Ga)(S,Se)2 solar cells.
The influence of thickness, interpore distance and compositional structure on the optical properties of self-ordered anodic aluminum oxide films
Authors: Manzano C. V. , Best J. P. , Schwiedrzik J. J. , Cantarero A. , Michler J. , Philippe L.
Published: August 2016

The reflectance was found to depend on the thickness of the AAO films and significantly on the inter-pore distance (pore density). The chemistry of the system plays an important role regarding the optical properties.
Highly transparent electrorheological fluids of silica nanoparticles: the effect of urea modification
Authors: Hao Bo Nan , Guo Yun Xia , Liu Ying Dan , Wang Li-Min , Choi Hyoung Jin
Published: August 2016

Highly transparent electrorheological (ER) fluids with enhanced ER properties were prepared using urea-modified silica nanoparticles.
Synthesis and dielectric properties of nanocrystalline oxide perovskites, [KNbO3]1−x[BaNi0.5Nb0.5O3−δ]x, derived from potassium niobate KNbO3 by gel collection
Authors: Lombardi Julien , Pearsall Frederick , Li Wanlu , O'Brien Stephen
Published: August 2016

Inorganic materials synthesis techniques that can approach low temperature routes akin to chemical solution processing are attractive for their ability to prepare nanocrystalline oxides.
Fluorescent graphene-like carbon nitrides: synthesis, properties and applications
Authors: Wang Ai-Jun , Li Hua , Huang Hong , Qian Zhao-Sheng , Feng Jiu-Ju
Published: August 2016

FL GCNs are a type of promising graphene-like nanomaterials, due to their large specific surface area, good biocompatibility, and optoelectronic and catalytic features. Herein, we have systematically described the different synthetic routes, properties and applications of FL GCNs.
Optical and electrical characterization of electrospun Al-doped zinc oxide nanofibers as transparent electrodes
Authors: Cho Yu-Yu , Kuo Changshu
Published: August 2016

Electrospun AZO nanofibers with precise controls of compositions, fiber diameters and fiber depositions for transparent electrode applications.
High‐aspect ratio microchannels fabricated in fused silica hollow fibres using Tesla coil
Authors: Yu Z. , Stjernström M. , Laurell F.
Published: August 2016

A novel method to fabricate microchannels into fused silica capillaries and hollow fibres by a high‐voltage high‐frequency corona discharge induced by a Tesla coil is demonstrated. Channels as narrow as 2.2 μm are successfully made in capillaries with 2 μm inner and 125 µm outer diameters.
ESD protection design and enhancement in the power 60‐V n‐channel LDMOS by embedded‐SCR anode islands
Authors: Chen S.‐L. , Chen K.‐J. , Chen H.‐W.
Published: August 2016

An electrostatic discharge (ESD) strengthening design of high‐voltage (HV) n‐channel laterally diffused metal–oxide semiconductor (nLDMOS) transistors combined with embedded‐SCR anode islands is investigated. After a systematic layout implementation and analysis, the anti‐ESD robustness [or secondary breakdown current (It2)] of drain pnp‐arranged and SCR isolated‐type DUTs were higher than 7‐A (ESD reliability improvements of these nLDMOS‐SCR devices were more than 282.5% (199.2%) higher than that of the pure nLDMOS (pnp‐stripe) component. Also, it can be found that the ESD robustness of the pnp‐arranged type is greater than the npn‐arrangement. Therefore, an adequate architecture of an HV nLDMOS device embedded with an SCR (pnp‐arranged) and SCR isolated manner can gain high ESD‐reliability immunity.
Energy‐efficient resource allocation for device‐to‐device communication with WPT
Authors: Dai Haibo , Huang Yongming , Li Chunguo , Li Shidang , Yang Luxi
Published: August 2016

In this study, the authors address the downlink resource (subchannels and power) allocation problem for device‐to‐device communication with wireless power transfer technique in a cellular network to improve the energy efficiency (EE). The considered problem is formulated as maximising the weighted EE and is solved by leveraging a game‐theoretic learning approach. Specifically, they first prove that an exact potential game applies to the resource allocation problem and there exists the best Nash equilibrium (NE) which is the optimal solution of the optimisation problem. Then, aiming to this optimisation problem with imperfect information, a robust and distributed learning algorithm is proposed and is proved that it can converge to the best NE. Finally, numerical results verify the effectiveness of the proposed scheme.
Dual‐hop signal space cooperative systems using multiple DF relays
Authors: Khan Muhammad Ajmal , Rao Raveendra K. , Wang Xianbin , Sheikh Asrar
Published: August 2016

In a dual‐hop relaying system without a direct link between the source and the destination, the source broadcasts information signal to the relay and relay broadcasts it to the destination, thus it uses two phases to transmit one symbol. This study proposes a novel scheme to incorporate signal space diversity into a dual‐hop relaying system with multiple decode‐and‐forward (DF) relays to enhance its spectral efficiency. The proposed dual‐hop signal space cooperative relaying scheme transmits two symbols in three phases while the conventional dual‐hop DF relaying system uses four phases to transmit the same two symbols. Therefore, the proposed scheme improves the spectral efficiency without additional complexity, bandwidth or transmit power. The proposed scheme is analysed over Rayleigh fading channel and error probability performance is derived. Moreover, an asymptotic approximation for the error probability is obtained to illustrate the impact of different system parameters and diversity gain. In addition, this study discusses the power allocation optimisation, relay position optimisation and the joint optimisation of both. Furthermore, closed‐form expression for the average channel capacity is derived. In the end, analytical results are compared and validated through Monte Carlo simulations.
Dynamic equivalent model of doubly fed wind farm during electromagnetic transient process
Authors: Jinxin Ouyang , Yanbo Diao , Di Zheng , Rui Yu , Xi Zhang , Xiaofu Xiong
Published: August 2016

The dynamic processes of a power system during grid fault are being changed by the large‐scale applications of wind generation. The transient characteristics of a single doubly fed induction generator (DFIG) have been widely researched. However, the overall characteristics of a wind farm have not been obtained because the existing models of a wind farm cannot cover the differences caused by normal instruction values, controller responses, and protections of the DFIGs. The equivalent model of a doubly fed wind farm used for the electromagnetic transient analysis is studied. The feature information of the stator short‐circuit current (SCC) of a DFIG was excavated based on transient behaviour analysis. The structure similarity indices are established to evaluate the envelope curves of the SCCs. A clustering method based on transient physical process is then proposed to distinguish coherent DFIGs. The equivalent model represented by a small number of DFIGs is obtained by aggregating coherent groups. The simulations indicate that the method effectively recognises transient state differences of the DFIGs. Thus, the model meets the requirements of the transient analysis.
Toward theoretical synthesis of biocomputer
Authors: Kuo Ting‐Yu , Lin Chun‐Liang , Charoenkit Natdanai , Chen Yang‐Yi , Preuksakarn Chakkrit
Published: August 2016

Increasing applications of fundamental biological gates have been successfully built during this decade. Proceeding to the current development, this study presents a genetic arithmetic and logical unit (ALU) design based on a series of genetic logic gates. The system level's architecture consists of three parts: temp register, ALU and accumulator register. Using the concept of the ALU on the digital computer, the authors present the fundamental function of the genetic ALU via full adder register and also build the bio‐storage devices to store data generated from the genetic ALU. The system in this study shows the capability of computing and storage on the biocomputer.
Treatment of Classic Syndromes in Idiopathic Focal Epilepsies in Childhood
Authors: Panayiotopoulos C. , Valeta Thalia
Published: August 2016

Of the classic syndromes of idiopathic (benign) focal epilepsies in childhood, more than half of children with Rolandic epilepsy and Panayiotopoulos syndrome do not need antiepileptic drug (AED) treatment. Monotherapy with carbamazepine, levetiracetam, sodium valproate, or clobazam is usually recommended for those with seizures that are unusually frequent (more than three), lengthy, distressing, or otherwise significantly interfering with the child's life. Other factors in favor of treatment include a short interval between the first three seizures, a younger age of onset (less than 4 years), or a presence of recurrent tonic–clonic seizures and diurnal seizures. In contrast to Rolandic epilepsy and Panayiotopoulos syndrome that may not need treatment, idiopathic childhood occipital epilepsy of Gastaut should be treated because seizures are frequent and secondarily generalized convulsions are probably unavoidable without medication. It is likely that all AEDs licensed as monotherapy for focal seizures and mainly carbamazepine and levetiracetam are suitable.

The electroencephalogram does not predict prognosis or AED treatment needs, though there are views supporting that interictal spikes have an adverse effect on cognition.

Strategies of withdrawing medication in idiopathic focal epilepsies in childhood differ among experts, although all agree that there is no need to continue medication 1 to 3 years after the last seizure, and certainly not after the age of 14 years, when most benign childhood focal seizures remit, or age 16, when they are practically nonexistent.

In the acute stage of status epilepticus, control of the seizures is of paramount importance. Convulsive status epilepticus is a life threatening condition and should be terminated as soon as possible. Autonomic status epilepticus needs thorough evaluation for proper diagnosis and management. Benzodiazepines, intravenously, in rectal or buccal preparations are commonly used to terminate long lasting seizures and status epilepticus. Early parental treatment is more effective than late emergency treatment. Buccal midazolam is probably the first choice medication for out-of-hospital termination of status epilepticus.

Parental education and psychological support are the cornerstone of the optimal management because despite excellent prognosis, idiopathic focal epilepsies in childhood usually have a dramatic impact to parents.
On the nature of high field charge transport in reinforced silicone dielectrics: Experiment and simulation
Authors: Huang Yanhui , Schadler Linda S.
Published: August 2016

The high field charge injection and transport properties in reinforced silicone dielectrics were investigated by measuring the time-dependent space charge distribution and the current under dc conditions up to the breakdown field and were compared with the properties of other dielectric polymers. It is argued that the energy and spatial distribution of localized electronic states are crucial in determining these properties for polymer dielectrics. Tunneling to localized states likely dominates the charge injection process. A transient transport regime arises due to the relaxation of charge carriers into deep traps at the energy band tails and is successfully verified by a Monte Carlo simulation using the multiple-hopping model. The charge carrier mobility is found to be highly heterogeneous due to the non-uniform trapping. The slow moving electron packet exhibits a negative field dependent drift velocity possibly due to the spatial disorder of traps.
Invited Article: Four-mode semiconductor optical amplifier
Authors: Wen He , Alahmadi Yousef , LiKamWa Patrick , Xia Cen , Carboni Christian , Li Guifang
Published: August 2016

We demonstrate the first few-mode semiconductor optical amplifier (FM SOA) that supports up to four waveguide modes. We show that each of the modes are confined to the waveguide, overlapping the quantum wells with approximately the same amount, leading to equalized gain for each of the four waveguide modes.
Comparison of fully internally and strongly contracted multireference configuration interaction procedures
Authors: Sivalingam Kantharuban , Krupicka Martin , Auer Alexander A. , Neese Frank
Published: August 2016

Multireference (MR) methods occupy an important class of approaches in quantum chemistry. In many instances, for example, in studying complex magnetic properties of transition metal complexes, they are actually the only physically satisfactory choice. In traditional MR approaches, single and double excitations are performed with respect to all reference configurations (or configuration state functions, CSFs), which leads to an explosive increase of computational cost for larger reference spaces. This can be avoided by the internal contraction scheme proposed by Meyer and Siegbahn, which effectively reduces the number of wavefunction parameters to their single-reference counterpart. The “fully internally contracted” scheme (FIC) is well known from the popular CASPT2 approach. An even shorter expansion of the wavefunction is possible with the “strong contraction” (SC) scheme proposed by Angeli and Malrieu in their NEVPT2 approach. Promising multireference configuration interaction formulations (MRCI) employing internal contraction and strong contraction have been reported by several authors. In this work, we report on the implementation of the FIC-MRCI and SC-MRCI methodologies, using a computer assisted implementation strategy. The methods are benchmarked against the traditional uncontracted MRCI approach for ground and excited states of small molecules (N2, O2, CO, CO+, OH, CH, and CN). For ground states, the comparison includes the “partially internally contracted” MRCI based on the Celani-Werner ansatz (PC-MRCI). For the three contraction schemes, the average errors range from 2% to 6% of the uncontracted MRCI correlation energies. Excitation energies are reproduced with ∼0.2 eV accuracy. In most cases, the agreement is better than 0.2 eV, even in cases with very large differential correlation contributions as exemplified for the d-d and ligand-to-metal charge transfer transitions of a Cu[NH3]42+ model complex. The benchmark is supplemented with the investigation of typical potential energy surfaces (i.e., N2, HF, LiF, BeH2, ethane C–C bond stretching, and the ethylene double bond torsion). Our results indicate that the SC-scheme, which is successful in the context of second- and third-order perturbation theory, does not offer computational advantages and at the same time leads to much larger errors than the PC and FIC schemes. We discuss the advantages and disadvantages of the PC and FIC schemes, which are of comparable accuracy and, for the systems tested, also of comparable efficiency.
On the motion of viscous, compressible, and heat-conducting liquids
Authors: Feireisl Eduard , Novotný Antonín , Sun Yongzhong
Published: August 2016

We consider a system of equations governing the motion of a viscous, compressible, and heat conducting liquid-like fluid, with a general equation of state (EOS) of Mie-Grüneisen type. In addition, we suppose that the viscosity coefficients may decay to zero for large values of the temperature. We show the existence of global-in-time weak solution, derive a relative energy inequality, and compare the weak solutions with strong one emanating from the same initial data—the weak strong uniqueness property.
Time-delayed transition of normal-to-abnormal glow in pin-to-water discharge
Authors: Yoon S.-Y. , Byeon Y.-S. , Yoo S. , Hong E. J. , Kim S. B. , Yoo S. J. , Ryu S.
Published: August 2016

Time-delayed transition of normal-to-abnormal glow was investigated in discharge between spoke-like pins and ultrapure water by applying AC-driven power at a frequency of 14.3 kHz at atmospheric pressure. The normal-to-abnormal transition can be recognized from the slope changes of current density, gas temperature, electrode temperature, and OH density. The slope changes took place in tens of minutes rather than just after discharge, in other words, the transition was delayed. The time-delay of the transition was caused by the interaction between the plasma and water. The plasma affected water properties, and then the water affected plasma properties.
An inexpensive technique for the time resolved laser induced plasma spectroscopy
Authors: Ahmed Rizwan , Ahmed Nasar , Iqbal J. , Baig M. Aslam
Published: August 2016

We present an efficient and inexpensive method for calculating the time resolved emission spectrum from the time integrated spectrum by monitoring the time evolution of neutral and singly ionized species in the laser produced plasma. To validate our assertion of extracting time resolved information from the time integrated spectrum, the time evolution data of the Cu II line at 481.29 nm and the molecular bands of AlO in the wavelength region (450–550 nm) have been studied. The plasma parameters were also estimated from the time resolved and time integrated spectra. A comparison of the results clearly reveals that the time resolved information about the plasma parameters can be extracted from the spectra registered with a time integrated spectrograph. Our proposed method will make the laser induced plasma spectroscopy robust and a low cost technique which is attractive for industry and environmental monitoring.
The transport characteristics of passing fast ions produced by nonlocal overlapping of drift island surfaces and magnetic island surfaces
Authors: Cao Jinjia , Gong Xueyu , Xiang Dong , Huang Qianhong , Yu Jun
Published: August 2016

The structure of the drift-island surface of passing fast ions (PFIs) is investigated in the presence of the resonant interaction with a magnetic island. Two overlapping regions of the drift-island surface and the magnetic island surface are found, one corresponding to local overlapping region and the other to non-local one. Here, the word “nonlocal” denotes that the resonances in the core plasma can have effects on the PFIs near the plasma boundary, while the “local” represents that the PFIs just near the resonant location are influenced. The nonlocal overlapping constructs a transport path along which the PFIs can become losses. There are three kinds of drift-island surfaces to join in forming the transport paths. A pitch angle region, which is called pitch angle gap, is found near the plasma boundary, where the drift-island surface cannot be formed and few PFIs are lost. The pitch-angle selective features of PFI losses are obtained by analyzing the three kinds of drift-island surfaces. The coupling between the crowd drift island surfaces and the collision can induce the prompt losses of PFIs and rapidly slowing down of PFI energy. The time of the prompt losses and the slowing down rate are calculated. Qualitatively, the theoretical results are in well agreement with the experimental observations in ASDEX Upgrade [M. García-Muñoz et al., Nucl. Fusion 47, L10 (2007)].
Buckling failure of square ice-nanotube arrays constrained in graphene nanocapillaries
Authors: Zhu YinBo , Wang FengChao , Wu HengAn
Published: August 2016

Graphene confinement provides a new physical and mechanical environment with ultrahigh van der Waals pressure, resulting in new quasi-two-dimensional phases of few-layer ice. Polymorphic transition can occur in bilayer constrained water/ice system. Here, we perform a comprehensive study of the phase transition of AA-stacked bilayer water constrained within a graphene nanocapillary. The compression-limit and superheating-limit (phase) diagrams are obtained, based on the extensive molecular-dynamics simulations at numerous thermodynamic states. Liquid-to-solid, solid-to-solid, and solid-to-liquid-to-solid phase transitions are observed in the compression and superheating of bilayer water. Interestingly, there is a temperature threshold (∼275 K) in the compression-limit diagram, which indicates that the first-order and continuous-like phase transitions of bilayer water depend on the temperature. Two obviously different physical processes, compression and superheating, display similar structural evolution; that is, square ice-nanotube arrays (BL-VHDI) will bend first and then transform into bilayer triangular AA stacking ice (BL-AAI). The superheating limit of BL-VHDI exhibits local maxima, while that of BL-AAI increases monotonically. More importantly, from a mechanics point of view, we propose a novel mechanism of the transformation from BL-VHDI to BL-AAI, both for the compression and superheating limits. This structural transformation can be regarded as the “buckling failure” of the square-ice-nanotube columns, which is dominated by the lateral pressure.
Upgrade of the tangentially viewing vacuum ultraviolet (VUV) telescope system for 2D fluctuation measurement in the large helical device
Authors: Wang Z. J. , Ming T. F. , Gao X. , Du X. D. , Ohdachi S.
Published: August 2016

A high-speed tangentially viewing vacuum ultraviolet (VUV) telescope system, using an inverse Schwarzschild-type optic system was developed to study fluctuations in the Large Helical Device (LHD). However, for the original system, the sampling rate was restricted to below 2000 Hz due to the low signal to noise (S/N) ratio in the experiment. In order to improve the S/N ratio, upgrade of the system was made. With this upgraded optical system, the maximum framing rate is improved to 6000 fps with a similar spatial resolution. Rotation of the m = 2 structure caused by the magnetohydrodynamic (MHD) instability is measured by the upgraded system. The spatial structure of the image is consistent with the synthetic image assuming the interchange mode type displacement of the flux surfaces.
Identification and mitigation of stray laser light in the Thomson scattering system on the Madison Symmetric Torus (MST)
Authors: Jacobson C. M. , Borchardt M. T. , Den Hartog D. J. , Falkowski A. F. , Morton L. A. , Thomas M. A.
Published: August 2016

The Thomson scattering diagnostic on the Madison Symmetric Torus (MST) records excessive levels of stray Nd:YAG laser light. Stray light saturates the 1064 nm spectral channel in all polychromators, which prevents absolute electron density measurements via Rayleigh scattering calibration. Furthermore, stray light contaminates adjacent spectral channels for r/a ≥ 0.75, which renders the diagnostic unable to make electron temperature measurements at these radii. In situ measurements of stray light levels during a vacuum vessel vent are used to identify stray light sources and strategies for reduction of stray light levels. Numerical modeling using Zemax OpticStudio supports these measurements. The model of the vacuum vessel and diagnostic includes synthetic collection optics to enable direct comparison of measured and simulated stray light levels. Modeling produces qualitatively similar stray light distributions to MST measurements, and quantifies the mitigation effects of stray light mitigation strategies prior to implementation.
Optimal thickness of silicon membranes to achieve maximum thermoelectric efficiency: A first principles study
Authors: Mangold Claudia , Neogi Sanghamitra , Donadio Davide
Published: August 2016

Silicon nanostructures with reduced dimensionality, such as nanowires, membranes, and thin films, are promising thermoelectric materials, as they exhibit considerably reduced thermal conductivity. Here, we utilize density functional theory and Boltzmann transport equation to compute the electronic properties of ultra-thin crystalline silicon membranes with thickness between 1 and 12 nm. We predict that an optimal thickness of ∼7 nm maximizes the thermoelectric figure of merit of membranes with native oxide surface layers. Further thinning of the membranes, although attainable in experiments, reduces the electrical conductivity and worsens the thermoelectric efficiency.
CMOS-compatible catalytic growth of graphene on a silicon dioxide substrate
Authors: Lee Jae-Hyun , Kim Min-Sung , Lim Jae-Young , Jung Su-Ho , Kang Seog-Gyun , Shin Hyeon-Jin , Choi Jae-Young , Hwang Sung-Woo , Whang Dongmok
Published: August 2016

We report the direct growth of graphene on a dielectric SiO2 surface by utilizing complementary metal oxide semiconductor compatible germane as a gas-phase catalyst. Results of Raman spectroscopy and XPS confirmed that the synthesized graphene consist of a sp2 hybridized carbon network. We were able to fabricate graphene field effect transistors without the wet etching process, and the calculated mobility was ∼160 cm2/V·s at high carrier concentration (n = 3 × 1012 cm−2). Furthermore, the crystallinity and morphology of graphene is easily controlled from single-layer graphene to graphene nanowall structures by adjusting the reaction conditions. The results of this study verify the promising catalytic graphene growth method on a non-catalytic insulating surface without metal contaminations.
A novel method to determine trimethylantimony concentrations in plant tissue
Authors: Mestrot Adrien , Ji Ying , Tandy Susan , Wilcke Wolfgang
Published: August 2016

Environmental contextAntimony enters the soil mostly through mining and shooting activities and can thereafter be taken up by plants. In the soil, antimony may undergo several transformations such as biomethylation, leading to the formation of trimethylantimony. Here, we measured for the first time the uptake and translocation of trimethylantimony in a plant using a new extraction and analysis method.
AbstractAntimony (Sb) is a relevant pollutant that can be found in elevated concentrations in soils near Sb mines and at shooting ranges. In soils, Sb occurs as trivalent Sb, SbIII, pentavalent Sb, SbV, or trimethylantimony, TMSb ((CH3)3SbO), the latter being the result of microbial biomethylation. It is important to understand the transfer of Sb species from soil to plants to assess the role of Sb in the food chain. However, this research has historically been hampered by the lack of suitable extraction and analytical methods. In this study, we validated an efficient and reliable extraction technique using oxalic acid and ascorbic acid (72.6±1.3% of Sb extracted) as well as a high-pressure liquid chromatography–inductively coupled plasma mass spectrometry (HPLC-ICP-MS) speciation analysis method to assess the uptake of TMSb in ryegrass (Lolium perenne L.), a common pasture plant, in a hydroponics experiment. Our results show that TMSb and SbIII are not converted to other species during extraction and that TMSb is taken up by ryegrass roots and translocated to the shoots. Our study also points at specific methylation–demethylation mechanisms occurring in the plant. Moreover, an unknown Sb species was found in the shoots of TMSb-treated plants, highlighting the need for further research. These new extraction and speciation methods will enable researchers to study the soil–plant transfer of organo-Sb compounds in a reliable and consistent manner.
The domesticated brain: genetics of brain mass and brain structure in an avian species
Authors: Henriksen R. , Johnsson M. , Andersson L. , Jensen P. , Wright D.
Published: August 2016

As brain size usually increases with body size it has been assumed that the two are tightly constrained and evolutionary studies have therefore often been based on relative brain size (i.e. brain size proportional to body size) instead of absolute brain size. The process of domestication offers an excellent opportunity to disentangle the linkage between body and brain mass due to the extreme selection for increased body mass that has occurred. By breeding an intercross between domestic chicken and their wild progenitor, we address this relationship by simultaneously mapping the genes that control inter-population variation in brain mass and body mass. Loci controlling variation in brain mass and body mass have separate genetic architectures and are therefore not directly constrained. Genetic mapping of brain regions in the intercross indicates that domestication has led to a larger body mass and to a lesser extent a larger absolute brain mass in chickens, mainly due to enlargement of the cerebellum. Domestication has traditionally been linked to brain mass regression, based on measurements of relative brain mass, which confounds the large body mass augmentation due to domestication. Our results refute this concept in chicken and confirm recent studies that show that different genetic architectures underlie these traits.
Single-Channel Recording of Ligand-Gated Ion Channels
Authors: Plested Andrew J.R.
Published: August 2016

Single-channel recordings reveal the microscopic properties of individual ligand-gated ion channels. Such recordings contain much more information than measurements of ensemble behavior and can yield structural and functional information about the receptors that participate in fast synaptic transmission in the brain. With a little care, a standard patch-clamp electrophysiology setup can be adapted for single-channel recording in a matter of hours. Thenceforth, it is a realistic aim to record single-molecule activity with microsecond resolution from arbitrary cell types, including cell lines and neurons.
Structures ofN-acetyl-DL-isoleucine,N-acetyl-DL-alloisoleucine and their ammonium salts; role of ammonium ions in crystal structure formation
Authors: Yajima Tatsuo , Kimura Makiko , Hori Yoshihiro , Shiraiwa Tadashi
Published: August 2016

The crystal structures ofN-acetyl-DL-isoleucine,N-acetyl-DL-alloisoleucine and their ammonium salts show that these four compounds exist as racemic compounds around room temperature. The two ammonium salts are arranged around a 21screw axis, forming a helical column which consists of ammonium ions and single enantiomeric anions similar to the crystals of the ammonium salts of optically activeN-acetyl-L-isoleucine andN-acetyl-D-alloisoleucine. The ammonium ion and the carboxylate ion in the helix are connected by three hydrogen bonds, the fourth hydrogen bond being formed between the ammonium ion and an external acetyl amino group of the neighboring helical column. The fourth hydrogen bond is formed between the ammonium ion and an external acetyl amino group of the neighboring 21column. AmmoniumN-acetyl-DL-alloisoleucinate was revealed to exist as an unstable racemic compound due to conformational similarity between the racemic and optically active compounds in the solid state and was optically resolved by fractional crystallization at 293 K.
Organic crystal polymorphism: a benchmark for dispersion-corrected mean-field electronic structure methods
Authors: Brandenburg Jan Gerit , Grimme Stefan
Published: August 2016

We analyze the energy landscape of the sixth crystal structure prediction blind test targets with variousfirst principlesandsemi-empiricalquantum chemical methodologies. A new benchmark set of 59 crystal structures (termed POLY59) for testing quantum chemical methods based on the blind test target crystals is presented. We focus on different means to include London dispersion interactions within the density functional theory (DFT) framework. We show the impact of pairwise dispersion corrections like the semi-empirical D2 scheme, the Tkatchenko–Scheffler (TS) method, and the density-dependent dispersion correction dDsC. Recent methodological progress includes higher-order contributions in both the many-body and multipole expansions. We use the D3 correction with Axilrod–Teller–Muto type three-body contribution, the TS based many-body dispersion (MBD), and the nonlocal van der Waals density functional (vdW-DF2). The density functionals with D3 and MBD correction provide an energy ranking of the blind test polymorphs in excellent agreement with the experimentally found structures. As a computationally less demanding method, we test our recently presented minimal basis Hartree–Fock method (HF-3c) and a density functional tight-binding Hamiltonian (DFTB). Considering the speed-up of three to four orders of magnitudes, the energy ranking provided by the low-cost methods is very reasonable. We compare the computed geometries with the corresponding X-ray data where TPSS-D3 performs best. The importance of zero-point vibrational energy and thermal effects on crystal densities is highlighted.
Crystal structure prediction: are we there yet?
Authors: Cruz-Cabeza Aurora J.
Published: August 2016

This contribution comments on the advances of the latest Crystal Structure Prediction blind test and the challenges still lying ahead.
Are board characteristics relevant for banking efficiency? Evidence from the US
Authors: Titova Yulia
Published: August 2016

Purpose

This paper aims to examine whether board-related characteristics matter for cost efficiency in banking sector.

Design/methodology/approach

This study uses a sample of publicly traded US commercial banks and savings institutions to estimate a relationship between cost efficiency measured by stochastic frontier analysis and a set of board-related characteristics for the period 2007-2013.

Findings

An inverted U-shape relation is found between board size and efficiency. Thus, there is a trade-off between costs and benefits of larger boards. Optimal board size is higher for banks with more complex operations. This study also observed an inverted U-shape relation between board independence and cost efficiency. The banks where the Chairman also executes the CEO responsibility show lower efficiency. However, a higher proportion of independent board members in banks with unitary leadership structure may mitigate the conflict of interest and lower efficiency stemming from CEO duality.

Research limitations/implications

This study’s evidence supports the Basel Committee on Banking Supervision emphasis on advising a board composition that provides for a sufficient degree of director independence.

Practical Implications

The results are relevant for banks and their external and internal stakeholders. Banks may adjust their current board characteristics to increase the board effectiveness. Externally, potential investors can evaluate the quality of corporate governance of banks before making investment decisions. The empirical findings can also be useful for regulators imposing corporate governance codes in banking.

Originality/value

To the best of the authors’ knowledge, this is the first paper to provide empirical evidence on the impact of board characteristics on bank efficiency for a wide panel of US banks. Additionally, a comprehensive set of board-related variables is used.
Does corporate governance beget firm performance in Fortune Global 500 companies?
Authors: Malik Muhammad Shaukat , Makhdoom Durayya Debaj
Published: August 2016

Purpose

This paper aims to determine the impact of corporate governance practices on the financial outcomes of Fortune Global 500 Companies, thus covering impact of geographical differences (USA and non-USA) as well.

Design/methodology/approach

The study is a quantitative research based on a positivist paradigm using deductive reasoning and secondary data collection. Data collection has been done from secondary sources (annual reports, Edgar submissions and financial statistics from renowned financial databases such as yahoo.finance, Bloomberg, Ycharts statistics and Morningstar. Data were collected for 8 years (2005-2012).

Findings

The study found a strong positive relationship between corporate governance and firm performance. Smaller board sizes are found to generate better firm performance in Fortune Global 500 Companies. Frequency of board meetings have also been found to have inverse relationship with firm performance. The study supports board independence to improve transparency in board decision-making process. CEO compensation has been found to have inverse relationship with firm performance. The robustness of our results has been measured with the usage of three dependent variables, and we have found same results with varying significance level.

Research limitations/implications

Due to selection of globally broad sample set qualitative aspects of corporate governance could not be covered. Nevertheless, there is a need to go beyond the quantitative techniques (secondary data) of measuring corporate governance mechanisms.

Practical implications

The population set is unique combination of big players and global diversification. Hence, the corporate governance practices of these firms as understood from the results of this study can be bench-marked for emerging corporates of varying global context.

Originality/value

The research is original and unique as it significant and globally diverse population of Fortune Global 500 Companies over a period of 8 years for 11 variables of interest. Results are helpful in bench marking for the rest of market players.
Numerical solution of MHD Sisko fluid over a stretching cylinder and heat transfer analysis
Authors: Malik M.Y. , Hussain Arif , Salahuddin T. , Awais M.
Published: August 2016

Purpose

– The purpose of this paper is to examine the Sisko fluid model over a stretching cylinder with heat transfer and magnetohydrodynamics.

Design/methodology/approach

– The boundary layer approach is employed to simplify the governing equations. Suitable similarity transformations are used to transform the governing partial differential equations into ordinary differential equations. In order to solve this system of ordinary differential equations numerically, shooting method in conjunction with Runge-Kutta-Fehlberg method is used.

Findings

– The effects of physical parameters involved in velocity and temperature profiles are shown through graphs. It is observed that Sisko fluid parameter and curvature parameter enhances fluid velocity while motion of fluid is retarded by increasing magnetic field strength. Additionally temperature of fluid raise with curvature parameter while it fall down for larger values of Prandtl number. Skin friction coefficient and Nusselt number are computed and presented in graphs and tables for further analysis. It can be seen that curvature parameter increases both skin friction and Nusselt number while magnetic field and Prandtl number decayed skin friction and Nusselt number, respectively. Also Sisko parameter enlarges skin friction coefficient. The accuracy of solution is verified by comparing it with existing literature.

Originality/value

– The computed results are interested for industrial and engineering processes, especially in cooling of nuclear reactors.
Propagation of plane waves of magneto-thermoelastic medium with voids influenced by the gravity and laser pulse under G-N theory
Authors: Othman Mohamed Ibrahim A , Hilal Mohamed I. M.
Published: August 2016

Purpose

– The purpose of this paper is to investigate the influence of the gravity and the magnetic fields on the plane waves in a homogenous, linear and isotropic thermoelastic medium subjected to the laser pulse heating.

Design/methodology/approach

– The problem has been solved analytically and numerically by using the normal mode analysis.

Findings

– Numerical results for the temperature, the displacement components, the stress components and the volume fraction were presented graphically and analyzed the results. The graphical results indicate that the effect of gravity and magnetic fields are observable physical effects on the porous thermoelastic material heated by a laser pulse. Comparisons are made with the results in the absence and presence of the gravity and the magnetic fields, also at various times.

Originality/value

– In the present work, the authors shall formulate a 2-D problem for the propagation of plane waves on the porous thermoelastic material influenced by the gravity and the magnetic fields subjected to a laser pulse heating act as a thermal shock. A comparison is also made between the two types II and III of Green-Naghdi theory in the absence and the presence of the gravity and the magnetic fields. Such problems are very important in many dynamical systems.
Thermal radiation effects on creep behavior of the turbine blade
Authors: Abdollahzadeh Jamalabadi Mohammad yaghoub
Published: August 2016

Purpose

– The purpose of this paper is to find the time dependent thermal creep stress relaxation of a turbine blade and to investigate the effect thermal radiation of the adjacent turbine blades on the temperature distribution of turbine blade and creep relaxation.

Design/methodology/approach

– For this analysis, the creep flow behavior of Moly Ascoloy in operational temperature of gas turbine in full scale geometry is studied for various thermal radiation properties. The commercial software is used to pursue a coupled fields analysis for turbine blades in view of the structural force, materials kinematic hardening, and steady-state temperature field.

Findings

– During steady-state operation, the thermal stress was found to be decreasing, whereas by considering the thermal radiation this rate was noticed to increase slightly. Also by increase of the distance between stator blades the thermal radiation effect is diminished. Finally, by decrease of the blade distance the failure probability and creep plastic deformation decrease.

Research limitations/implications

– This paper describes the effect of thermal radiation in thermal-structural analysis of the gas turbine stator blade made of the super-alloy M-152.

Practical implications

– Blade failures in gas turbine engines often lead to loss of all downstream stages and can have a dramatic effect on the availability of the turbine engines. There are many components in a gas turbine engine, but its performance is highly profound to only a few. The majority of these are hotter end rotating components.

Social implications

– Three-dimensional finite element thermal and stress analyses of the blade were carried out for the steady-state full-load operation.

Originality/value

– In the previous works the thermal radiation effects on creep behavior of the turbine blade have not performed.
The Effect of Local Hydration Environment on the Mechanical Properties and Unloaded Temporal Changes of Isolated Porcine Annular Samples
Authors: Gruevski Kristina M. , Gooyers Chad E. , Karakolis Thomas , Callaghan Jack P.
Published: August 2016

Preventing dehydration during in vitro testing of isolated layers of annulus fibrosus tissue may require different test conditions than functional spine units. The purpose of the study was twofold: (A) to quantify changes in mass and thickness of multilayer annulus samples in four hydration environments over 120 min; and (B) to quantify cycle-varying biaxial tensile properties of annulus samples in the four environments. The environments included a saline bath, air, relative humidity control, and misting combined with controlled humidity. The loading protocol implemented 24 cycles of biaxial tensile loading to 20% strain at a rate of 2%/s with 3-, 8-, and 13-min of intermittent rest. Specimen mass increased an average (standard deviation) 72% (11) when immersed for 120 min (p < 0.0001). The air condition and the combined mist and relative humidity conditions reduced mass by 45% (15) and 25% (23), respectively, after 120 min (p < 0.0014). Stress at 16% stretch in the air condition was higher at cycle 18 (18 min of exposure) and cycle 24 (33 min of exposure) compared to all other environments in both the axial and circumferential directions (p < 0.0460). There was no significant change in mass or thickness over time in the relative humidity condition and the change in circumferential stress at 16% stretch between cycles 6 and 24 was a maximum of 0.099 MPa and not statistically significant. Implementation of a controlled relative humidity environment is recommended to maintain hydration of isolated annulus layers during cyclic tensile testing.
A Multiscale Approach for Nonlinear Dynamic Response Predictions With Fretting Wear
Authors: Armand J. , Pesaresi L. , Salles L. , Schwingshackl C. W.
Published: August 2016

Accurate prediction of the vibration response of aircraft engine assemblies is of great importance when estimating both the performance and the lifetime of their individual components. In the case of underplatform dampers, for example, the motion at the frictional interfaces can lead to a highly nonlinear dynamic response and cause fretting wear at the contact. The latter will change the contact conditions of the interface and consequently impact the nonlinear dynamic response of the entire assembly. Accurate prediction of the nonlinear dynamic response over the lifetime of the assembly must include the impact of fretting wear. A multiscale approach that incorporates wear into the nonlinear dynamic analysis is proposed, and its viability is demonstrated for an underplatform damper system. The nonlinear dynamic response is calculated with a multiharmonic balance approach, and a newly developed semi-analytical contact solver is used to obtain the contact conditions at the blade–damper interface with high accuracy and low computational cost. The calculated contact conditions are used in combination with the energy wear approach to compute the fretting wear at the contact interface. The nonlinear dynamic model of the blade–damper system is then updated with the worn profile and its dynamic response is recomputed. A significant impact of fretting wear on the nonlinear dynamic behavior of the blade–damper system was observed, highlighting the sensitivity of the nonlinear dynamic response to changes at the contact interface. The computational speed and robustness of the adopted multiscale approach are demonstrated.
A parametric vocal fold model based on magnetic resonance imaging
Authors: Wu Liang , Zhang Zhaoyan
Published: August 2016

This paper introduces a parametric three-dimensional body-cover vocal fold model based on magnetic resonance imaging (MRI) of the human larynx. Major geometric features that are observed in the MRI images but missing in current vocal fold models are discussed, and their influence on vocal fold vibration is evaluated using eigenmode analysis. Proper boundary conditions for the model are also discussed. Based on control parameters corresponding to anatomic landmarks that can be easily measured, this model can be adapted toward a subject-specific vocal fold model for voice production research and clinical applications.