bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of B‐Site Niobium‐Doped Pr0.4Sr0.6 (Co0.3Fe0.6)1‐xNbxO3‐δ (x=0, 0.05, 0.1, 0.2) Perovskites as Cathode Materials for Solid Oxide Fuel Cells
Authors: Xiaokaiti Pairuzha , Yu Tao , Yoshida Akihiro , Zuo Zhijun , Hao Xiaogang , Guan Guoqing , Abudula Abuliti
Published: May 2018

Perovskite materials of Pr0.4Sr0.6(Co0.3Fe0.6)1‐xNbxO3‐δ (PSCFNx, x=0, 0.05, 0.1, 0.2) were firstly synthesized as the cathode materials for solid oxide fuel cells (SOFCs) by doping niobium(Nb) at the B site of Pr0.4Sr0.6Co0.3Fe0.6O3‐δ using a solid state reaction method. The effect of Nb doping amount on the lattice structure, oxygen desorption and electrochemical properties of PSCFNx at different calcination temperatures were investigated. It is found that this material family had perfectly cubic structure based on the Pm‐3 m space group whose lattice size increased with x. These materials were thermally stable after calcination and showed desirable chemical compatibility with electrolyte in the condition of calcination at 1250 °C for 8 h under an air atmosphere. The optimum x value of 0.1 was found for the PSCFNx cathode materials, which had the minimum polarization resistance value of 0.018 Ωcm2 at 900 °C. As a result, the single cell with the PSCFN0.1 cathode delivered a power density of 0.731 Wcm−2 at 900 °C with humidified H2 (∼3% H2O) as the fuel and ambient air as the oxidant. It indicates that PSCFN0.1 should be a promising cathode material for the SOFCs.
Rapid In Situ Encapsulation of Laccase into Metal‐Organic Framework Support (ZIF‐8) under Biocompatible Conditions
Authors: Patil Pravin D. , Yadav Ganapati D.
Published: May 2018

In situ immobilization of laccase into metal‐organic framework (laccase‐MOF) was performed by assisting one‐pot synthesis strategy. A novel method to synthesize octahedral laccase‐MOF composite with enhanced thermostability is reported. The present work deals with entrapment of laccase into zeolitic imidazolate framework (ZIF‐8) by simply mixing solution of zinc acetate, 2‐methylimidazole, and laccase at room temperature (28 ± 2 °C). Fourier transform‐infrared spectroscopy (FT‐IR), Scanning electron microscopy (SEM), Thermogravimetric analysis (TGA), and Confocal scanning microscopy were employed to characterize laccase‐MOF composite. The thermostability of prepared composite was assessed concerning half‐life at varying temperatures which conferred 3.6‐fold enhancement over free enzyme. Also, kinetic studies of immobilized laccase showed a slightly higher Km and lower Vmax values along with the enhancement of thermodynamic parameters after non‐covalent interaction. Moreover, the immobilized laccase‐MOF maintained up to 48% of residual activity for seven subsequent cycles in batch mode, whereas the storage stability studies exhibited up to 83% up to 21 days of storage. Finally, FT‐IR data tool was employed to investigate the effect of encapsulation on fractions of secondary structure of protein.
Stability and Aromaticity of Some Superatomic Compounds Al3‐X (X=F, LiF2, BeF3, BF4)
Authors: Yu Ang‐yang
Published: May 2018

This work makes use of Al3 clusters and fluorine atom or its superhalogens (LiF2, BeF3, BF4) as the basic unit to design a new series of Aluminum clusters‐superatomic compounds Al3‐X (X=F, LiF2, BeF3, BF4) theoretically. The most stable orientation for Al3‐F can be found when one of the aluminum atoms in Al3 ring is adjacent to fluorine atom, whereas the best orientation between Al3 and superhalogen (LiF2, BeF3 or BF4) exists when one of the aluminum atoms in Al3 ring has the shortest distance with F−F bond in superhalogen (LiF2, BeF3 or BF4) ring. Large frontier molecular orbital energy gap and binding energy in these compunds, as well as Atoms‐In–Molecule theoretical analysis prove that there is good stability between Al3 and fluorine atom or its superhalogens (LiF2, BeF3, BF4). Additionally, aromaticity of Al3‐X compound has been confirmed by means of Nucleus‐independent chemical shift (NICS) calculation of Al3 ring in these compounds. This work can provide useful information for new materials synthesis, as well as fabrication of new superatomic compounds.
Hydrodeoxygenation of Octanoic Acid over the Mo–Doped CeO2‐Supported Bimetal Catalysts: The Role of Mo
Authors: Shen Pengxin , Wei Ruiping , Zhu M. Yanli , Pan Donghui , Xu Siquan , Gao Lijing , Xiao Guomin
Published: May 2018

Nonsulfided CeO2‐supported different metal catalysts were synthesized, characterized and evaluated in the hydrogenation of octanoic acid with a batch reactor at the temperature of 280 oC and initial H2 pressure of 3 MPa. The effect of Mo species was revealed by comparing Mo‐doped catalysts with Mo‐free catalysts. The catalytic results show that the CeO2 supported Ni catalyst doped with Mo exhibit much higher catalytic activity and octane selectivity than the catalysts without dopants. Additionally, the influences of Mo and Ni mass ratio on the conversion of octanoic acid and the selectivity of heptane and octane over CeO2‐based catalysts were also discussed. Ni species seemed beneficial for the deoxygenation reaction to form C7 alkane, while the doping of Mo favored the hydrodeoxygenation path to C8 alkane via dehydration‐hydrogenation of the octanol intermediate.
High Density of a New Fused Heterocycle: 7,8‐Dinitro‐4‐oxo‐4,6‐dihydropyrazolo[5, 1‐d][1, 2,3,5]tetrazine 2‐oxide and Its Energetic Salts
Authors: Zhao Bao‐Jing , Wang Piaopiao , Fu Wei , Li Chuan , Zhou Zhi‐Ming
Published: May 2018

In this work, the new fused heterocyclic compound 7,8‐dinitro‐4‐oxo‐4,6‐dihydropyrazolo[5, 1‐d][1, 2,3,5]tetrazine (HPCM) and its energetic salts were designed and synthesized. All energetic salts were fully characterized by 1H and 13C nuclear magnetic resonance spectroscopy, infrared spectroscopy, and elemental analysis. The structures of the sodium and 3,4,5‐triamino‐1,2,4,–triazolium salts were further confirmed by single‐crystal X‐ray diffraction. In addition, their key physicochemical properties such as density, thermal stability, and sensitivity towards impact and friction were also evaluated. The salts were thermally stable with decomposition temperatures ranging from 171 to 315 °C. Theoretical calculations associated with heats of formation and detonation performance were performed by Gaussian 03 and EXPLO5 v6.01 programs, respectively. All of the salts were found to have positive heats of formation. Taking both experimental and computational parameters into consideration, the fact that hydroxylammonium salt showed a high density (ρ=1.95 g cm–3), acceptable decomposition temperature (Td=171 °C), excellent detonation performance (P=39.4 Gpa, vD=9228 m s–1) and favorable impact and friction sensitivities (IS=19 J, FS=360 N), indacate that it has the potential to be used as a less sensitive high energy density material.
Synthesis, Electrochemical, Antibacterial and Anticancer Studies on Triazole‐Bridged Pyrrolidine‐Grafted Macrocycles via [3+2] Cycloaddition of Azomethin Ylide
Authors: Prabhakaran Perumal , Subaraja Mamangam , Rajakumar Perumal
Published: May 2018

An efficient and regioselective synthesis of triazole bridged pyrrolidine grafted macrocycle derivatives was accomplished by O‐alkylation, followed by aldol/Wittig reaction, click reaction with salicylaldehyde and finally by intramolecular 1, 3‐dipolar cycloaddition (1,3‐DC) to with azomethin ylide. The regio‐ and stereochemical outcome of the reaction was unambiguously established by single crystal X‐ray analysis of the cycloadducts. All the synthesized macrocycles exhibit irreversible oxidation reduction signals in cyclic voltammetry. Antioxidant property and antibacterial activity against Bacillus cereus and Klebsiella pneumoniae bacteria and anticancer activity against human adenocarcinoma breast cancer cell line cells (MCF‐7) revealed that all the pyrrolidine grafted macrocycles showed activity comparable to that of the standard drug.
Multiple Cores‐Shell Structured Cu@SiO2 Ultrathin Leaf‐Shaped Nanocomposite: Facile Fabrication and Excellent Selective Catalytic Hydrogenation Performance
Authors: Liu Jun , Liu Dan , Zhang Yingbo , Wang Jing , Li Hongmei , Zhou Li , Wu Shan
Published: May 2018

The facile preparation core‐shell structured Cu@SiO2 nanocomposites with high copper loading and dispersion still remains a difficult challenge. Herein, we report the efficient fabrication of a core‐shell structured Cu@SiO2 leaf‐shaped nanocatalyst which possesses multiple copper nanoplatelets with high content as cores and ultrathin mesoporous silica as shell. This catalyst exhibits excellent catalytic performance in gas phase catalytic hydrogenation of furfural (with furfural conversion of 97% and furfuryl alcohol selectivity of 98%) and liquid phase catalytic reduction of p‐nitrophenol to p‐aminophenol (with activity parameter =69.0×10−3 s−1 mg−1). This unique fabrication strategy is also successfully applied to synthesize multiple cores‐shell structured Ni@SiO2 nanosheet composite with uniform and ultrafine nickel particles and extremely high nickel loading. It is expected that this strategy can be expanded to other diverse multiple core‐shell architectures.
Synthesis and Magnetic Properties of L‐Alanine Capped CoFe2O4 Nanoparticles
Authors: Serrano‐García Raquel , Purcell‐Milton Finn , McCarthy Sarah , Gun'ko Yurii K.
Published: May 2018

Here we report a low cost scalable synthesis of L‐alanine capped CoFe2O4 magnetic nanoparticles, with excellent size tunability and magnetic properties. Samples were analyzed in details using electron microscopy, X‐ray powder diffraction and vibrational sample magnetometry. The magnetic nanoparticles have demonstrated excellent size distribution, uniformity and phase purity. It was found that the presence and concentration of L‐alanine ligand dramatically affects the size and morphology of the resulting CoFe2O4 nanoparticles, enabling size tunability from 120.5 to 11.3 nm. The magnetic moments of nanomaterials are ranging from 74 to 41 Am2kg−1, they are easily manipulated by an external magnetic field and show the onset of superparamagnetic behavior in the smaller nanoparticles prepared.
Structural Effects on Guest Binding in Cucurbit[8]uril‐Perylenemonoimide Host‐Guest Complexes
Authors: Aryal Gyan H. , ViK Ryan , Assaf Khaleel I. , Hunter Kenneth W. , Huang Liming , Jayawickramarajah Janarthanan , Nau Werner M.
Published: May 2018

A series of water‐soluble fluorescent perylene dyes (perylenemonoimides PMI1, PMI2, and PMI3) with two aromatic binding units (a perylene‐core and a phenyl group) as guest molecules for binding with cucurbit[8]uril (CB8) were synthesized. The guest structure was varied by modifying the phenyl group and the spacer between the two binding units. Differences in binding, self‐assembly, and optical properties of the corresponding host‐guest complexes were observed. At low micromolar concentrations, a highly emissive 1:1 CB8•PMI1 complex with high binding affinity (Ka=1.5 x 107 M–1) was formed in water. Interestingly, at higher concentrations of the CB8•PMI1 complex (e. g., >10–4 M), non‐emissive self‐assembled nanowires were formed. In comparison, the binding affinity of CB8•PMI2 and CB8•PMI3 was determined to be only 5.0 x 105 M–1 and 1.7 x 104 M–1, respectively. The host‐guest complexes with various binding affinities could serve as fluorescent displacement probes for the detection of a range of CB8‐binding guest analytes.
Catalytic Selective Hydrogenation and Cross Coupling Reaction Using Polyvinylpyrrolidone‐Capped Nickel Nanoparticles
Authors: Bathla Aadil , Pal Bonamali
Published: May 2018

This study signifies the size‐dependent catalytic activity of Ni‐nanocatalyst for the selective hydrogenation of cinnamaldehyde and Suzuki‐Miyaura cross‐coupling reaction. A series of polyvinylpyrrolidone capped nickel nanoparticles (NPs) with variation in their size are synthesized by polyol method. The morphological studies revealed that average size of Ni‐NPs (Ni‐NP1, Ni‐NP2, and Ni‐NP3) lies in the range of 10–12, 7–9, and 3–5 nm respectively. The optical measurements showed a significant blue shift in the absorption spectra for Ni‐NPs with decreasing particle size. The magnetic hysteresis loop revealed that the remanent magnetization (MR) decreases and coercivity (HC) increases with the decrease in particle size demonstrating a distinct size effect. The Ni‐NP3 was observed to possess higher surface area (79 m2g−1) and efficient activity for the selective hydrogenation of cinnamaldehyde to cinnamyl alcohol and also in the biphenyl formation via C−C cross‐coupling reaction relative to Ni‐NP1, Ni‐NP2, and commercially available Raney Ni.
Combining Whispering‐Gallery Mode Optical Biosensors with Microfluidics for Real‐Time Detection of Protein Secretion from Living Cells in Complex Media
Authors: Chen Ying‐Jen , Schoeler Ulrike , Huang Chung‐Hsuan (Benjamin) , Vollmer Frank
Published: May 2018

The noninvasive monitoring of protein secretion of cells responding to drug treatment is an effective and essential tool in latest drug development and for cytotoxicity assays. In this work, a surface functionalization method is demonstrated for specific detection of protein released from cells and a platform that integrates highly sensitive optical devices, called whispering‐gallery mode biosensors, with precise microfluidics control to achieve label‐free and real‐time detection. Cell biomarker release is measured in real time and with nanomolar sensitivity. The surface functionalization method allows for antibodies to be immobilized on the surface for specific detection, while the microfluidics system enables detection in a continuous flow with a negligible compromise between sensitivity and flow control over stabilization and mixing. Cytochrome c detection is used to illustrate the merits of the system. Jurkat cells are treated with the toxin staurosporine to trigger cell apoptosis and cytochrome c released into the cell culture medium is monitored via the newly invented optical microfluidic platform.
High‐Contrast SEM Imaging of Supported Few‐Layer Graphene for Differentiating Distinct Layers and Resolving Fine Features: There is Plenty of Room at the Bottom
Authors: Huang Li , Zhang Dan , Zhang Fei‐Hu , Feng Zhi‐Hong , Huang Yu‐Dong , Gan Yang
Published: May 2018

For supported graphene, reliable differentiation and clear visualization of distinct graphene layers and fine features such as wrinkles are essential for revealing the structure–property relationships for graphene and graphene‐based devices. Scanning electron microscopy (SEM) has been frequently used for this purpose where high‐quality image contrast is critical. However, it is surprising that the effect of key imaging parameters on the image contrast has been seriously undermined by the graphene community. Here, superior image contrast of secondary electron (SE) images for few‐layer graphene supported on SiC and SiO2/Si is realized through simultaneously tuning two key parameters—acceleration voltage (Vacc) and working distance (WD). The overlooked role of WD in characterizing graphene is highlighted and clearly demonstrated. A unified model of Vacc and WD dependence of three types of SE collected by the standard side‐attached Everhart‐Thornley (E‐T) SE detector is conceptually developed for mechanistically understanding the improved mass thickness contrast for supported few‐layer graphene. The findings reported here will have important implications for effective characterizations of atomically thick 2D materials and devices.
Ferroelectric Localized Field–Enhanced ZnO Nanosheet Ultraviolet Photodetector with High Sensitivity and Low Dark Current
Authors: Wang Peng , Wang Yang , Ye Lei , Wu Mingzai , Xie Runzhang , Wang Xudong , Chen Xiaoshuang , Fan Zhiyong , Wang Jianlu , Hu Weida
Published: May 2018

Zinc oxide (ZnO) nanosheets have demonstrated outstanding electrical and optical properties, which are well suited for ultraviolet (UV) photodetectors. However, they have a high density of intrinsically unfilled traps, and it is difficult to achieve p‐type doping, leading to the poor performance for low light level switching ratio and a high dark current that limit practical applications in UV photodetection. Here, UV photodetectors based on ZnO nanosheets are demonstrated, whose performance is significantly improved by using a ferroelectric localized field. Specifically, the photodetectors have achieved a responsivity of up to 3.8 × 105 A W−1, a detectivity of 4.4 × 1015 Jones, and a photocurrent gain up to 1.24 × 106. These device figures of merit are far beyond those of traditional ZnO ultraviolet photodetectors. In addition, the devices' initial dark current can be easily restored after continuous photocurrent measurement by using a positive gate voltage pulse. This study establishes a new approach to produce high‐sensitivity and low‐dark‐current ultraviolet photodetectors and presents a crucial step for further practical applications.
Mineral‐Templated 3D Graphene Architectures for Energy‐Efficient Electrodes
Authors: Zhang Mingchao , Chen Ke , Wang Chunya , Jian Muqiang , Yin Zhe , Liu Zhenglian , Hong Guo , Liu Zhongfan , Zhang Yingying
Published: May 2018

3D graphene networks have shown extraordinary promise for high‐performance electrochemical devices. Herein, the chemical vapor deposition synthesis of a highly porous 3D graphene foam (3D‐GF) using naturally abundant calcined Iceland crystal as the template is reported. Intriguingly, the Iceland crystal transforms to CaO monolith with evenly distributed micro/meso/macropores through the releasing of CO2 at high temperature. Meanwhile, the hierarchical structure of the calcined template could be easily tuned under different calcination conditions. By precisely inheriting fine structure from the templates, the as‐prepared 3D‐GF possesses a tunable hierarchical porosity and low density. Thus, the hierarchical pores offer space for guest hybridization and provide an efficient pathway for ion/charge transport in typical energy conversion/storage systems. The 3D‐GF skeleton electrode hybridized with Ni(OH)2/Co(OH)2 through an optimal electrodeposition condition exhibits a high specific capacitance of 2922.2 F g−1 at a scan rate of 10 mV s−1, and 2138.4 F g−1 at a discharge current density of 3.1 A g−1. The hybrid 3D‐GF symmetry supercapacitor shows a high energy density of 83.0 Wh kg−1 at a power density of 1011.3 W kg−1 and 31.4 Wh kg−1 at a high power density of 18 845.2 W kg−1. The facile fabrication process enables the mass production of hierarchical porous 3D‐GF for high‐performance supercapacitors.
Light Sources and Photodetectors Enabled by 2D Semiconductors
Authors: Shang Jingzhi , Cong Chunxiao , Wu Lishu , Huang Wei , Yu Ting
Published: May 2018

The emerging 2D semiconductors have aroused increasing attention due to their fascinating fundamental properties and application prospects. Technical investigation of 2D semiconductor–based electronics and optoelectronics is paving the way to realizing practical applications, which opens up new opportunities to reshape the current semiconductor industry. Particularly, 2D semiconductor–based optoelectronics can be extensively utilized in the promising semiconductor and information industries, such as solid‐state lighting, on‐chip optical interconnects, quantum computing, and communication. Here, the research progress regarding the fabrication and characterization of rapidly growing light‐emitting devices and photodetectors enabled by 2D semiconductors is reviewed. According to different emission mechanisms, 2D semiconductor–activated light sources are classified into four types: excitonic light‐emitting diodes (LEDs), quantum LEDs, valley LEDs, and lasers. Moreover, photodetecting devices based on atomically thin MoS2, other 2D semiconductors, and van der Waals heterostructures are discussed, where diverse device structures, performance parameters, and working principles are compared. Furthermore, the remaining challenges in the realization of practical devices with desirable features are outlined and new research opportunities for 2D semiconductor optoelectronics are proposed.
Influence of Synthesis Conditions on Electrochemical Properties of P2‐Type Na2/3Fe2/3Mn1/3O2 for Rechargeable Na Batteries
Authors: Zhao Wenwen , Tsuchiya Yuka , Yabuuchi Naoaki
Published: May 2018

P2‐type Na2/3Fe2/3Mn1/3O2 samples are synthesized by solid‐state calcination with different conditions and the influence of synthesis conditions on the structural and electrochemical properties is systematically studied. By controlling the synthesis conditions, a fraction of O3‐type impurity phase is effectively decreased, and nearly stoichiometric P2 Na2/3Fe2/3Mn1/3O2 is successfully obtained by a two‐step calcination method. A voltage plateau of 2.5 V, which is attributed to the oxidation of Mn3+ to Mn4+, appears in initial charge profiles for quenched and one‐step calcined samples. In contrast, for the initial charge process, the voltage plateau of 2.5 V is not observed in the sample prepared in the two‐step calcination process, suggesting that Mn3+ is not contained in this sample. Charge/discharge mechanisms of nearly stoichiometric Na2/3Fe2/3Mn1/3O2 are also examined by X‐ray absorption spectroscopy and X‐ray diffractometry, and it is found that reversible redox reaction of Fe3+/Fe4+ and Mn3+/Mn4+ proceeds on electrochemical cycles. Moreover, stacking faults associated with metal layer glide on charge are more pronounced for P2 Na2/3Fe2/3Mn1/3O2 in comparison to the P2‐type Mn‐rich system, Na2/3Fe1/2Mn1/2O2. From these results, factors affecting electrode performance of sodium insertion materials are discussed.
Cobalt@Nitrogen‐Doped Porous Carbon Fiber Derived from the Electrospun Fiber of Bimetal–Organic Framework for Highly Active Oxygen Reduction
Authors: Bai Qing , Shen Feng‐Cui , Li Shun‐Li , Liu Jiang , Dong Long‐Zhang , Wang Zeng‐Mei , Lan Ya‐Qian
Published: May 2018

The exploitation of high‐efficiency, cost‐effective, and stable oxygen reduction reaction (ORR) electrocatalysts is extremely critical for energy storage and conversion technology. The transition metal carbonitrides have been investigated as an alternative to precious metal‐based catalysts. Here, a series of uniform Co nanoparticles encapsulated in nitrogen‐doped porous carbon fibers (Co@N‐PCFs for brevity) are designed and synthesized by directly carbonizing the ZnxCo1–x‐zeolitic imidazolate frameworks@polyacrylonitrile (ZnxCo1–x‐ZIFs@PAN) electrospun nanofibers. By precisely controlling the Zn/Co molar ratio in the ZnxCo1–x‐ZIFs precursor and carbonization temperature, a higher activity and stability ORR catalyst of Co@N‐PCF‐3 is prepared. The results reveal that Co@N‐PCF‐3 exhibits outstanding ORR activity outperformed commercial Pt/C with more positive half‐wave potential of −134 mV versus Ag/AgCl, high selectivity to four‐electron pathway (n ≈ 3.9), as well as remarkable stability and methanol tolerance. Remarkably, it is one of the highest ORR catalysts among the cobalt carbonitrides reported in the literature.
Synergistic Modifications of Side Chains and End Groups in Small Molecular Acceptors for High Efficient Non‐Fullerene Organic Solar Cells
Authors: Feng Huanran , Yi Yuan‐Qiu‐Qiang , Ke Xin , Zhang Yamin , Wan Xiangjian , Li Chenxi , Chen Yongsheng
Published: May 2018

Two new acceptor‐donor‐acceptor (A‐D‐A) type non‐fullerene acceptors, O‐NTIC and O‐NTNC, using hexacyclic naphthalene (cyclopentadithiophene) (NT) as the electron‐donating unit, and dicycanovinylindan‐1‐one (INCN) or phenyl‐fused dicycanovinylindan‐1‐one (NINCN) as the electron‐deficient unit, respectively, are synthesized. From the perspective of synthesis easiness and cost, para‐alkoxy‐phenyl is used as side chains of the NT core. It is worth noting that the introduction of para‐alkoxy‐phenyl unit could tune the molecular energy levels and lift the open‐circuit voltage (Voc). Compared with O‐NTIC, the introduction of extended end‐groups NINCN leads to a more ordered packing structure, much red‐shifted absorption and enhanced electron mobility of O‐NTNC. With polymer PBDB‐T as the donor, the organic solar cell (OSC) devices obtain a decent power conversion efficiency (PCE) of 9.1% for O‐NTIC and much improved PCE of 11.0% for O‐NTNC, respectively. Moreover, with a polythiophene derivative named PDCBT as the donor material, the PDCBT:O‐NTNC based device exhibits a PCE of 10.0%, among the highest PCEs for PDCBT devices. These results indicate that O‐NTNC has great potential on the application for high performance and low‐cost OSCs, and the extended end group NINCN as well as para‐alkoxy‐phenyl side chain substituted core could be promising units for the design of materials with high performance.
An integral boundary layer engineering model for vortex generators implemented in XFOIL
Authors: De Tavernier Delphine , Baldacchino Daniel , Ferreira Carlos
Published: May 2018

To assess and optimize vortex generators (VGs) for flow separation control, the effect of these devices should be modelled in a cost and time efficient way. Therefore, it is of interest to extend integral boundary layer models to analyse the effect of VGs on airfoil performance. In this work, the turbulent boundary layer formulation is modified using a source term approach. An additional term is added to the shear‐lag equation, to account for the increased dissipation due to streamwise vortex action in the boundary layer, forcing transition at the VG leading edge where applicable. The source term is calibrated and a semi‐empirical relation is set up and implemented in XFOIL. The modified code is capable of addressing the effect of the VG height, length, inflow angle, and chordwise position on the airfoil's aerodynamic properties. The predicted polars for airfoils with VGs show a good agreement with reference data, and the code robustness is demonstrated by assessing different airfoil families at a wide range of Reynolds numbers.
The existence results for a new 2‐D compressible fluid model with the horizontal thermal gradient effect
Authors: Yang Jiayan , Liu Ruikuan
Published: May 2018

Based on the Newton second law, the energy conservation law, the mass conversation law and the equation of state, a new 2‐D model for the motion of fluid flows with the horizontal thermal gradient effect is established. By using the characteristic method, the classic prior estimates and iterative technique, the local existence and uniqueness of strong solution for the new 2‐D model are proved.
Subleading Regge limit from a soft anomalous dimension
Authors: Brüser Robin , Caron-Huot Simon , Henn Johannes M.
Published: May 2018

Abstract

Wilson lines capture important features of scattering amplitudes, for example soft effects relevant for infrared divergences, and the Regge limit. Beyond the leading power approximation, corrections to the eikonal picture have to be taken into account. In this paper, we study such corrections in a model of massive scattering amplitudes in$$ \mathcal{N}=4 $$N=4super Yang-Mills, in the planar limit, where the mass is generated through a Higgs mechanism. Using known three-loop analytic expressions for the scattering amplitude, we find that the first power suppressed term has a very simple form, equal to a single power law. We propose that its exponent is governed by the anomalous dimension of a Wilson loop with a scalar inserted at the cusp, and we provide perturbative evidence for this proposal. We also analyze other limits of the amplitude and conjecture an exact formula for a total cross-section at high energies.
On the evolution process of two-component dark matter in the Sun
Authors: Chen Chian-Shu , Lin Yen-Hsun
Published: May 2018

Abstract

We introduce dark matter (DM) evolution process in the Sun under a two-component DM (2DM) scenario. Both DM species χ and ξ with masses heavier than 1 GeV are considered. In this picture, both species could be captured by the Sun through DM-nucleus scattering and DM self-scatterings, e.g. χχ and ξξ collisions. In addition, the heterogeneous self-scattering due to χ and ξ collision is essentially possible in any 2DM models. This new introduced scattering naturally weaves the evolution processes of the two DM species that was assumed to evolve independently. Moreover, the heterogeneous self-scattering enhances the number of DM being captured in the Sun mutually. This effect significantly exists in a broad range of DM mass spectrum. We have studied this phenomena and its implication for the solar-captured DM annihilation rate. It would be crucial to the DM indirect detection when the two masses are close. General formalism of the 2DM evolution in the Sun as well as its kinematics are studied.
Fish–prey interactions in, and associated data from, a temperate stream of the Yura River, Kyoto, Japan
Authors: Nakagawa Hikaru , Takemon Yasuhiro
Published: May 2018

Although quantitative data on interspecific interactions within complex food webs are essential for evaluation of assumptions, hypotheses, and predictions of ecological theories; empirical studies yielding quantitative data on complex food webs are very limited. Ecological information on body size, habitat use, and seasonality of the component species of food webs aids in determining the mechanisms of food web structures. Ideally, ecological information on component species should be obtained contemporaneously when used to describe quantitative food webs, but such observations and sampling strategies are labor intensive and thus have been rarely described. We conducted year‐round samplings of, and performed observations on, a temperate stream: the upper reaches of the Yura River, Kyoto, Japan. We derived quantitative data on the abundance, biomass, body mass, microhabitat use, and those seasonality of 7 fish species and 167 invertebrate taxa of the temperate stream food web. In addition, we estimated the per mass consumption rates of 7 predatory fish species, consuming 183 prey invertebrates, and the ratios between the per mass consumption rates of the 7 predatory fish species and the production rates of 78 prey invertebrates in each trophic link. All fishes and aquatic invertebrates were identified to species or lowest possible taxon. Our data may contribute to the construction of mathematical models explaining the behavior of stream communities/ecosystems.
Sources of Fluoride Contamination in Singrauli with Special Reference to Rihand Reservoir and its Surrounding
Authors: Usham A. L. , Dubey C. S. , Shukla D. P. , Mishra B. K. , Bhartiya G. P.
Published: May 2018

The Singrauli region is known for fluoride contamination and its effect on human population. In this work the possible sources of fluoride contamination in Rihand reservoir water is constrained. They include slurry water, fly ash and coal samples of various thermal power plants, coal seams and granites of the region. Petrographic study depicted the presence of fluoride bearing minerals - flour apatite in pink granite. Preliminary scanning electron microscope studies revealed presence of fluorine peak in coal samples. The chemical analysis confirmed the presence of fluoride in fly ash (12.6 mg/kg), drain water (5.34 mg/l), soil (6.1 mg/kg), coal (3.1 mg/kg). They confirmed the source of fluoride from coal of thermal power plant which utilized coal from Singrauli coal seam (1.6 mg/kg). Further the Rihand reservoir water is also enriched by fluoride contaminant (upto 4.7 mg/l). This contaminates groundwater of the area as well. The contaminated water used for drinking and agriculture affects health of inhabitants in the area. It is concluded that the main source of fluoride contamination in the study area is due to coal burnt in thermal power plant and pink granite formation of the area, both anthropogenic and geogenic sources are implied.
Assessment of Potential Alkali Aggregate Reactivity for Siliceous and Carbonate Aggregates: A Case Study
Authors: Ahmad M. , Ansari M. K. , Singh Rajesh , Sharma L. K. , Singh T. N. , Pires Sandra
Published: May 2018

Alkali-aggregate reactivity (AAR) involves a reaction between the pore solution of concrete and certain minerals found in some aggregates. To assess the potential AAR various physical and chemical tests are available and extensively used. The petrographic examination is the initial assessment that decides the further investigation for potential reactivity of an aggregate. A chemical approach is another option to assess the aggregate for potential AAR. The accelerated mortar bar method and concrete prism tests are other very important tests for determination of potential AAR of aggregates samples. However, a combination of the results of all the techniques provides most reliable results for potential AAR in aggregates. Moreover, each test represents the stepwise investigation and provides the decision for the test of next approach. Petrographic examination and chemical test methods are the quick decision-making methods for the estimation of potential AAR. In some cases, by these two methods, the aggregate can be selected and rejected confidently. However, for critical values or doubtful aggregates, further tests are necessary to develop a higher confidence level of the results. The present study comprises of the assessment of the alkali-reactivity of siliceous and carbonate aggregates using petrographic and chemical approaches. X-ray diffraction analysis was used as a complementary method to the petrographic evaluation. Moreover, under chemical approach, two separate test methods were used for siliceous and carbonate aggregates. The study also included a comparison between the petrographic examination and chemical analysis for the same aggregate samples and found significant results.
Hydrogeochemistry and Groundwater Quality Assessment for Drinking and Irrigation Purpose of Raipur City, Chhattisgarh
Authors: Khan Rubia , Jhariya D. C.
Published: May 2018

Groundwater is an important source of drinking and irrigation purpose and the greater part of the total populace relies on groundwater for survival. Present study investigates the hydrogeochemistry and groundwater quality of the study area for drinking and irrigation purpose. In this study, total 100 numbers groundwater samples were collected and analyzed using standard methods (APHA, 1995) during pre-monsoon period (May, 2016). In the study area, there is occurrence of mainly Ca+2–Mg+2–HCO3 and Ca+2-M+2-SO4–2 water type and the dominant cations and anions are Ca>Mg>Na>K>Fe=HCO3>Cl>CO3> SO4>Fe>F>NH3. The Gibbs plot shows that, hydrogeochemistry of ground-water is depending upon rock-water interaction. Present study, indicate that groundwater quality in the study area is suitable for irrigation and drinking purpose except some groundwater sample, which are showing high Nitrate, Iron, Sulphate, Ammonia and Calcium concentration.
Rock Slope Stability Assessment Using Geomechanical Classification and its Application for Specific Slopes along Kodaikkanal-Palani Hill Road, Western Ghats, India
Authors: Sujatha Evangelin Ramani , Thirukumaran V.
Published: May 2018

Linear infrastructure networks like roads play a vital role in the socio-economic development of hill towns centered on tourism. Stability of the slopes along the hill roads are therefore a major concern and slope failures lead to disruption of traffic and loss of property/life or both. This study analyses the stability of cut-slopes along the Kodaikkanal – Palani hill road in the Western Ghats, India using rock mass classification systems like rock mass rating (RMR), slope mass rating (SMR) and continuous slope mass rating (CSMR). These geomechanical classifications provide a preliminary assessment of rock quality based on rock strength, discontinuity properties, hydrogeological condition of the slopes and slope stability based on the inherent rock strength parameters, discontinuity orientation and method of excavation. The results showed that both rock quality and discontinuity orientation contribute to type of failure in rock slopes with RMR > 40. SMR results are conservative while CSMR classification is matches more closely to the failures obtained from the field survey. CSMR classification represents continuous slope stability conditions and hence are more suitable for development of spatial database. Cutting of roads, thereby, steepening slopes has a definite influence on the stability of slopes.
Mineralogy and Geochemistry of Sedimentary Huntite Deposits in the Egirdir-Hoyran Lake Basin of Southern Turkey
Authors: Kuscu Mustafa , Cengiz Oya , Kahya Asuman
Published: May 2018

>The sediment-hosted huntite-magnesite deposits are located in the Egirdir-Hoyran lake basin in the Isparta Angle (southern Turkey). The deposits occur at two different localities in the region: (1)Kemersirti huntite deposit, (2) Köytepe huntite-magnesite deposit. The huntite-magnesite occurrences are found in shallow lacustrine rocks of the Miocene-Pliocene Kizilcik Formation and formed as a result of Neogene tectonic activity. Based on X-ray diffraction and scanning electron microscopic studies, the mineral assemblage of huntite deposits contains mostly huntite, less magnesite, dolomite, very little calcite, illite, simectite, brucite, and quartz in the Kemersirti area but contain huntite, magnesite, dolomite, and calcite in the Köytepe area.

In the huntite and magnesite-bearing huntite samples, MgO varies from 32.70 to 37.95 wt. %, CaO from 7.83 to 15.10 w.t. %, and SiO2 from 0.99 to 10.60 w.t. %. Ba and Sr are dominant minor elements in the deposits. Ba and Sr for huntite and magnesite bearing huntite in the study area vary from 11 to 233 ppm and from 325 to 765 ppm, respectively. As, U, Zr, V and Ce contents ranged from 11.5-146 ppm, 0.5-3.7 ppm, 1.4-13.2 ppm, 7-34 ppm, and 0.9-2.7 ppm respectively. The huntite-magnesite is characterized by relatively lower Ni (0.5-2.4 ppm) and Co (0.5-1.1 ppm) contents. The huntite and magnesite-bearing huntite occurrences have higher Ba, Sr, As, Zr, V, and U contents than those of the other elements. The δ13C isotope values vary between 7.8‰ to 8.8‰ PDB for huntite+magnesite, 8.2‰ PDB for huntite, 1.4‰ PDB for magnesite+dolomite, and 4.0‰ PDB for limestone from deposits in the study area. The δ18O isotope values of the huntite deposits ranged from 30.4 to 35.5‰ SMOW for huntite+magnesite, 32.4‰ SMOW for huntite, 29.8‰ SMOW for magnesite+ dolomite, and 26.9‰ SMOW for limestone.

The presence of nodular huntite and the abundance of gastropod, ostracoda and Chura shells in the carbonate units indicate that the huntite occurrences are precipitated at shallow, alkaline (8.5-9.5 pH) and lower temperature (approximately 25°C) lake conditions. The Mg++, Ca++ and Si++ ions for the huntite formation were derived from the surrounding rocks such as ultrabasic rocks, dolomite, dolomitic limestone, and limestone in the Egirdir-Hoyran lake basin. Also, the C isotope ratios indicate that the CO2 source for the huntite formations results to sedimentary basin from metamorphic CO2, carbonate rocks, fresh water carbonates, and ground water. The source of oxygen for the huntite formation may come from marine limestone, fresh water carbonates and meteoric water.
The sources of Russia’s fear of NATO
Authors: Tsygankov Andrei P.
Published: May 2018

The paper analyzes Russia’s perception of NATO since the beginning of its eastern enlargement. Russia’s reaction to the enlargement evolved from attempts to diffuse its potential damage through a limited cooperation to passive and then active policies of containment. The latter have resulted in a risky behavior with respect to the alliance and a concentration of Russian military on the Western border. Two factors can assist us in explaining Russia’s evolving perception of NATO from a potential partner to a renewed military threat — the historical experience of viewing the alliance, and theWest in general, as potentially threatening and the post-Cold war interaction with NATO that served to strengthen the historically developed perception. As of today, Russia has learned from its interaction with the alliance that NATO remains a principle threat to Russia’s national security and that through the alliance’s expansion the West seeks to exercise its cultural, economic, and political domination in Eurasia.
MODELLING AND ESTIMATING INDIVIDUAL AND FIRM EFFECTS WITH COUNT PANEL DATA
Authors: Angers Jean-François , Desjardins Denise , Dionne Georges , Guertin François
Published: May 2018

We propose a new parametric model for the modelling and estimation of event distributions for individuals in different firms. The analysis uses panel data and takes into account individual and firm effects in a non-linear model. Non-observable factors are treated as random effects. In our application, the distribution of accidents is affected by observable and non-observable factors from vehicles, drivers and fleets of vehicles. Observable and unobservable factors are significant to explain road accidents, which mean that insurance pricing should take into account all these factors. A fixed effects model is also estimated to test the consistency of the random effects model.
Academic Standards or Academic Imperialism? Zimbabwean perceptions of hegemonic power in the global construction of knowledge
Authors: Jeater Diana
Published: May 2018

University cultures in the Global North generate powerful definitions of what constitutes “knowledge” and “good research.” When we ask who gets to represent the “African perspective,” we find it is decreasingly an African. This article argues that resource inequalities alone cannot explain this exclusion of African scholarship. Hegemonic academic standards undervalue the more positivist research orientation found in southern African universities. The struggle is not over the validity of that orientation, but over who has the power to validate it. This analysis is based upon interviews with senior university research managers in Zimbabwe and on a public roundtable on Structural Inequalities in Global Academic Publishing.
A Bibliometric Profile of Disaster Medicine Research from 2008 to 2017: A Scientometric Analysis
Authors: Zhou Liang , Zhang Ping , Zhang Zhigang , Fan Lidong , Tang Shuo , Hu Kunpeng , Xiao Nan , Li Shuguang
Published: May 2018

This study analyzed and assessed publication trends in articles on “disaster medicine,” using scientometric analysis. Data were obtained from the Web of Science Core Collection (WoSCC) of Thomson Reuters on March 27, 2017. A total of 564 publications on disaster medicine were identified. There was a mild increase in the number of articles on disaster medicine from 2008 (n=55) to 2016 (n=83). Disaster Medicine and Public Health Preparedness published the most articles, the majority of articles were published in the United States, and the leading institute was Tohoku University. F. Della Corte, M. D. Christian, and P. L. Ingrassia were the top authors on the topic, and the field of public health generated the most publications. Terms analysis indicated that emergency medicine, public health, disaster preparedness, natural disasters, medicine, and management were the research hotspots, whereas Hurricane Katrina, mechanical ventilation, occupational medicine, intensive care, and European journals represented the frontiers of disaster medicine research. Overall, our analysis revealed that disaster medicine studies are closely related to other medical fields and provides researchers and policy-makers in this area with new insight into the hotspots and dynamic directions. (Disaster Med Public Health Preparedness. 2019;13:165–172)
Entrepreneurship as worship: A Malay Muslim perspective
Authors: Sidek Farhana , Pavlovich Kathryn , Gibb Jenny
Published: May 2018

While Islam is the second largest religion in the world with 1.6 billion Muslims, there are variations in the interpretations of that law (i.e., Sharia). This diversity and variation may hold the key in explaining the different behaviours among Muslim entrepreneurs because of their views on the concept of work as worship. In this study, we examine how Malay entrepreneurs are guided in their sourcing and shaping of entrepreneurial opportunities through Shafii practice. Our contributions include identifying five central values that guided the participant’s sourcing of opportunities: Fardhu Kifayah (communal obligation), Wasatiyyah (balanced), Dakwah1 (the call of joining the good and forbidding the bad), Amanah (trust), and Barakah (blessings). We also contribute to the entrepreneurship literature by demonstrating how these macro-level values of worship gave the entrepreneurs confidence in creating their new ventures.
Emotions and failure in academic life: Normalising the experience and building resilience
Authors: Edwards Marissa S , Ashkanasy Neal M
Published: May 2018

While a wealth of evidence exists about failure in organisational settings and the emotions evoked by failure, researchers have paid less attention to failure and its related emotional consequences in academic life. Given that failure is often a cause of significant stress, which in turn can lead to damaging consequences, we argue that this is an issue deserving of greater consideration. In this article, we adopt Ashkanasy’s five-level model of emotion in organisations, and explore the potential role of emotions in academics’ experiences of failure at five levels: within-person, between-persons, interpersonal interactions, groups and teams (and leadership), and organisation-wide. In doing so, we draw on findings from scholarly literature, anecdotal evidence, and our own experiences as academics to build arguments. Following discussion of the model, we suggest how academics might begin to normalise the experience of failure in academia and to build resilience in the coming generations of young scholars.
Monitoring and simulation of hydrothermal conditions indicating the deteriorating stability of a perennially frozen moraine dam in the Himalayas
Authors: WANG XIN , YANG CHENGDE , ZHANG YANLIN , CHAI KAILGUO , LIU SHIYIN , DING YONGJIAN , WEI JUNFENG , ZHANG YONG , HAN YONGSHUN
Published: May 2018

Thermal and hydrological dynamics and their impacts on the stability of a moraine dam were analyzed and simulated for the Longbasaba Lake in the Himalaya, based on soil temperature, moisture and heat flux data observed at different depths in the dam from 2012 to 2016. Annual average heat income is greater than heat expenditure on the dam surface. The mean annual temperature at observed the depths of 0–150 cm is >0°C, although the average annual air temperature was −3.6°C over the dam, indicating a relatively larger temperature difference between moraine dam and air. The volumetric soil moisture content is relatively low with an annual average of 5%, peaking after the snow cover melting and active layer thawing. Simulation results indicate that the average yearly maximum thawing depth has been ~0.3 m deeper than the average yearly maximum freezing depth during the observation period. In the past 55 years, the yearly maximum thawing depth has increased, while yearly maximum freezing depth has decreased, implying that the permafrost in the dam has been deteriorating. The annual surplus heat and increasing permafrost thawing depth will result in further deterioration of permafrost and melting of buried ice in the dam, thereby decreasing its stability.
Smiles, turnout, candidates, and the winning of district seats
Authors: Asano Masahiko , Patterson Dennis P.
Published: May 2018

Research has shown that a candidate’s appearance affects the support he or she receives in elections. We extend this research in this article in three ways. First, we examine this relationship further in a non-Western context using 2015 local elections in Japan. Next, we show that this positive relationship is more complicated depending on the characteristics of the election under consideration. Specifically, we distinguished election contests by levels of turnout and found that despite a positive relationship between turnout and the extent to which smiling increases a candidate’s support levels, the marginal increase in support declined as turnout increased and, in fact, became negative when some high-turnout threshold was crossed. Finally, we show that the number of candidates competing in an election is negatively related to the impact of a candidate smiling, confirming research conducted by the Dartmouth Group.