bluuebunny/crossref_metadata_2025 huggingface dataset:
Probing the effect of ferroelectric to paraelectric phase transition on the Ti-3d and O-2p hybridization in BaTiO3
Authors: Panchal Gyanendra , Choudhary R. J. , Yadav Satish , Phase D. M.
Published: June 2019

We report the modifications in the electronic properties of single phase polycrystalline BaTiO3 due to ferroelectric to paraelectric phase transition revealed by temperature dependent synchrotron based x-ray absorption and valence band spectroscopy. Valence band spectra show a strong temperature dependence of Ti-3d and O-2p hybridized states around the phase transition. It is observed that Ti-O hybridization is stronger in the paraelectric phase, which is also supported by multiplet calculations at the Ti L-edge. We also find a reduced crystal field value in the paraelectric phase than in the ferroelectric phase, which is caused by volume expansion and a reduction in tetragonal distortion.
Study of wall ablation on low-voltage arc interruption: The effect of Stefan flow
Authors: Huo Jindong , Selezneva Svetlana , Jacobs Linda , Cao Yang
Published: June 2019

Low-voltage circuit breakers provide essential protection for industrial and residential power installations, by taking advantage of the voltage drop at the electrode–plasma interface to force current zero. This is accomplished by using the magnetic force and unbalanced pressure on the arc as the contacts open to push the arc toward a stack of steel plates that break the arc into subarcs and thereby multiply the number of voltage drops. As the fault current can be high, substantial energy can be dissipated, which results in interactions among the arc and solid counterparts in terms of wall ablation and metal evaporation. In this study, ablation experiments are conducted to demonstrate its great influence on the arc voltage and on the pressure field. Significant progress has been accomplished in the computation of arc dynamics through the coupling of fluid motion with electromagnetics, although an important mechanism in arc breaking simulation, the effect of Stefan flow caused by species generation, has not been considered. We report out a numerical approach for taking into account the effect of Stefan flow, particularly for the breakers with high gasifying wall materials. This approach accounts for the diffusion induced convection due to added-in species from the evaporation surfaces, which will largely influence the flow field and the properties of the plasma mixture. Apart from the voltage drop, this mechanism plays an important role in simulating arc interruption. The ability of conducting Stefan flow computation further enhances the understanding of arc behaviors and improves the design of practically oriented low-voltage circuit breakers.
Effect of wall boundary on the scrape-off layer losses of high harmonic fast wave in NSTX and NSTX-U
Authors: Kim Eun-Hwa , Bertelli Nicola , Ono Masayuki , Valeo Ernest J. , Hosea Joel C. , Perkins Rory J.
Published: June 2019

We perform numerical simulations of high harmonic fast waves (HHFWs) in the scrape-off-layer (SOL) of National Spherical Torus Experiment (NSTX)/NSTX-U using a recently developed 2D full wave code. We particularly show that a realistic NSTX SOL boundary can significantly affect HHFW propagation and power losses in the SOL. In NSTX SOL boundaries, HHFW is easily localized near the antenna and propagates less to the SOL, and thus, less power is lost to the SOL. We also show that the lower SOL power losses occur when the SOL volume is smaller and the distance between the last closed flux surface and the antenna is shorter. We investigate the effect of electron density in front of the antenna and the ambient magnetic field strengths on the SOL power losses as well. Showing consistency with the experiments, SOL losses are minimized when the SOL density is near the critical density where the fast wave cutoff is open, and the plasma is strongly magnetized.
Kapitza thermal resistance characterization of epitaxial graphene–SiC(0001) interface
Authors: Hamaoui Georges , Dagher Roy , Cordier Yvon , Michon Adrien , Potiron Sylvain , Chirtoc Mihai , Horny Nicolas
Published: June 2019

This work presents the measurements of the Kapitza thermal boundary resistance (TBR) between two types of graphene monolayers epitaxially grown on the silicon face of SiC(0001) substrates by chemical vapor deposition. The studied systems consist of a graphene layer either separated from the bulk SiC by a carbon rich interface layer (called buffer layer BL) exhibiting a 63×63R30° surface reconstruction or quasifreestanding on the substrate, which will be referred to as QFSMG (for the quasifreestanding monolayer of graphene). The equivalent graphene monolayers' thermal resistances (ratio between the layer thickness and its thermal conductivity) and their respective TBR with the SiC substrates were characterized using a high frequency photothermal radiometry technique in order to distinguish the difference between the two interfaces. The results display a larger TBR through the BL compared to a lower one across the QFSMG. It is suggested that beyond generally used models, the presence of electronic coupling between the QFSMG and the SiC may create new channels for heat conduction at the interface. These results give new insights into the thermal transport at the nanoscale using epitaxial graphene monolayers for better usage in heat management applications (e.g., thermal diodes or thermal transistors).
Vibrationally resolved excitation, dissociation, and rotational cross sections of NH radical by electron-impact using the R-matrix method
Authors: Gupta Dhanoj , Baluja K. L. , Song Mi-Young
Published: June 2019

The ab initio R-matrix method is employed to study the electronic excitation of low-lying target states, the dissociation cross sections, and the rotational cross sections of the NH radical by electron impact for energies up to 15 eV. We have included dynamic interaction in our scattering model that uses close coupling formalism. There are 24 target states whose vertical excitation energies are below 15 eV, which are included in the trial wavefunction of the entire scattering system. In our scattering model, two electrons are frozen in the 1σ2 configuration and the remaining six electrons are free to move in the molecular orbitals 2σ 3σ 4σ 5σ 6σ 1π and 2π. The cc-pVTZ Dunning basis sets are used to optimize the target structure and electron scattering. The vibrationally resolved cross sections for transition from the ground state X 3Σ− to excited state c 1Π are computed by scaling the corresponding electronic excitation cross section by Franck-Condon factors. These factors are evaluated by using accurate potential energy curves of the ground state and the c excited state. We have compared the excitation cross section for the optically allowed transition X 3Σ− to A 3Π computed using our scattering model with the corresponding cross section evaluated in Born approximation, and the agreement is quite good indicating that for a reasonably high transition moment and a low threshold of the excited state, the effects of correlation and polarization are not very significant. The dissociative excitation cross section by electron impact into atomic fragments N and H is also shown which are caused mainly by c 1Π and a purely repulsive state 1 5Σ−. We have also shown that the vibrational cross section evaluated in Born approximation for the fundamental transition 0–1 of the ground state is quite small as compared to the rotational cross sections. The rotational cross sections are computed for j = 0 to j′ = 0–5, and it is shown that the dipole induced transition is predominant with an order of magnitude higher than the pure rotational 0–0 cross section. We have detected many low-lying core-excited shape resonances and provided their resonance parameters which form an important input to estimate dissociative electron attachment cross sections.
Numerical method for nonlinear optical spectroscopies: Ultrafast ultrafast spectroscopy
Authors: Rose Peter A. , Krich Jacob J.
Published: June 2019

We outline a novel numerical method, called Ultrafast Ultrafast (UF2) spectroscopy, for calculating the nth-order wavepackets required for calculating n-wave mixing signals. The method is simple to implement, and we demonstrate that it is computationally more efficient than other methods in a wide range of use cases. The resulting spectra are identical to those calculated using the standard response function formalism but with increased efficiency. The computational speed-ups of UF2 come from (a) nonperturbative and costless propagation of the system time-evolution, (b) numerical propagation only at times when perturbative optical pulses are nonzero, and (c) use of the fast Fourier transform convolution algorithm for efficient numerical propagation. The simplicity of this formalism allows us to write a simple software package that is as easy to use and understand as the Feynman diagrams that organize the understanding of n-wave mixing processes.
Theory of photo-ionization defects in nano-porous SiC alloys
Authors: Tuttle Blair R. , Summers Tyler , Barger Colton , Noonan Joseph , Pantelides Sokrates T.
Published: June 2019

Photoionization experiments have aided in the characterization of defects in numerous materials including nanoporous silicon carbide (SiC) alloys. We report first-principles calculations of dangling bond defect levels in microscopic models of nanoporous SiC. We used hybrid density functional methods to determine the photoionization energies needed to excite electrons from carbon defects into the conduction bands of SiC alloys, including oxidized SiC. We also examine the energetics and electronic structure of carbon dangling bonds with and without oxygen nearest neighbor interactions. Oxidized carbon dangling bond defects have properties that are consistent with recent photoionization experiments in nanoporous oxidized SiC. Hyperfine calculations provide new predictions to be tested experimentally.
Numerical solution of predator-prey model with Beddington-DeAngelis functional response and fractional derivatives with Mittag-Leffler kernel
Authors: Ghanbari Behzad , Kumar Devendra
Published: June 2019

One of the major applications of the nonlinear system of differential equations in biomathematics is to describe the predator–prey problem. In this framework, the fractional predator–prey model with Beddington-DeAngelis is examined. This model is formed of three nonlinear ordinary differential equations to describe the interplay among populations of three species including prey, immature predator, and mature predator. The fractional operator used in this model is the Atangana–Baleanu fractional derivative in Caputo sense. We show first that the fractional predator–prey model has a unique solution, then propose an efficient numerical scheme based on the product integration rule. The numerical simulations indicate that the obtained approximate solutions are in excellent agreement with the expected theoretical results. The numerical method used in this paper can be utilized to solve other similar models.
Predict-first experiments and modeling of perturbative cold pulses in the DIII-D tokamak
Authors: Rodriguez-Fernandez P. , White A. E. , Howard N. T. , Grierson B. A. , Zeng L. , Yuan X. , Staebler G. M. , Austin M. E. , Odstrcil T. , Rhodes T. L. , Sciortino F. , Rice J. E. , Thome K. E. , Angioni C. , Fable E. , Meneghini O.
Published: June 2019

Cold pulses are introduced in Ohmic DIII-D tokamak plasmas via injection of impurities with a laser blow-off system, revealing for the first time in this machine a quick increase in core electron temperature shortly after the edge cold-pulse injection at low collisionality. The experimental results are consistent with predict-first simulations of heat transport enabled by the Trapped Gyro-Landau-Fluid transport model. Measurements of electron density evolution during the cold-pulse propagation are enabled by a high time resolution density profile reflectometer. The density evolution reveals the quick propagation of a pulse from edge to core, which is a mechanism to transiently increase core temperature in low-collisionality plasmas. Local transport simulations with measured density evolution demonstrate that the core temperature response can indeed be explained by the stabilization of Trapped Electron Mode turbulence at low collisionality, thus providing confidence that local transport modeling is enough to explain cold-pulse propagation and associated phenomenology.
Influence of the magnetic field sweeping rate on magnetic transitions in synthetic ferrimagnets with perpendicular anisotropy
Authors: Morgunov R. B. , Kunitsyna E. I. , Talantsev A. D. , Koplak O. V. , Fache T. , Lu Y. , Mangin S.
Published: June 2019

The evolution of the switching field between stable states in MgO/CoFeB/Ta/CoFeB/MgO/GaAs and Pt/Co/Ir/Co/Pt/Ta/SiO2 synthetic ferrimagnets with perpendicular anisotropy as a function of the magnetic field sweeping rate (MFSR) of 0.1–104 Oe/s has been studied. The most significant effect of the MFSR is an inversion of the interstate transition sequence. In the MgO/CoFeB/Ta/CoFeB/MgO/GaAs heterostructure, the increase in MFSR switches the dominant mechanism of magnetization reversal from propagation of domain walls to a nucleation of reversed magnetization areas. In Pt/Co/Ir/Co/Pt/Ta/SiO2, the MFSR affects the final domain state of the transition, starting from the initial antiparallel configuration of the synthetic ferrimagnet.
Direct simulation Monte Carlo applications to liquid-vapor flows
Authors: Frezzotti A. , Barbante P. , Gibelli L.
Published: June 2019

The paper aims at presenting Direct Simulation Monte Carlo (DSMC) extensions and applications to dense fluids. A succinct review of past and current research topics is presented, followed by a more detailed description of DSMC simulations for the numerical solution of the Enskog-Vlasov equation, applied to the study of liquid-vapor flows. Results about simulations of evaporation of a simple liquid in contact with a dense vapor are presented as an example.
High sensitivity hexagonal boron nitride lateral neutron detectors
Authors: Maity A. , Grenadier S. J. , Li J. , Lin J. Y. , Jiang H. X.
Published: June 2019

Hexagonal boron nitride (h-BN) thermal neutron detectors have demonstrated the highest detection efficiency among all solid-state detectors (at 58% for a detection area of 1 mm2 and 53% for a detection area of 9 mm2). However, scaling up the detector size of vertical h-BN detectors is challenging due to increased dark current, capacitance, and surface recombination with the increasing detection area. Here, we report the demonstration of a 29 mm2 thermal neutron detector fabricated from a freestanding 10B enriched h-BN epilayer of 90 μm in thickness with a detection efficiency of 50% by employing a lateral device geometry. The lateral detector geometry takes advantage of the unique layered structure of h-BN which naturally provides higher in-plane carrier mobilities than those in the vertical direction. Moreover, due to the reduced area of metals in contact with the h-BN material, the detrimental effects associated with the surface recombination at the metal contacts and device capacitance were reduced, which resulted in improved charge collection efficiency and signal to noise ratios. This work laid the ground work for scaling up to large size neutron detectors based on h-BN.
Acoustic wave transmission channel based on phononic crystal line defect state
Authors: Han Jianning , Tang Shuai , Wang Rui , Wang Wen
Published: June 2019

To generate directional transmission characteristics of acoustic waves, we constructed two abnormal transmission models based on the protocell. The simulation results showed that the band gap characteristic of the phononic crystal structure can be used to realize the directional transmission effect. We also found that the acoustic frequency has a great influence on the acoustic transmission characteristics of artificial acoustic structures. Because the artificial acoustic structure based on phononic crystals has the advantages of design flexibility, it can be customized according to the actual engineering application. Our results provided a new direction for engineering applications such as directional transmission of acoustic waves and acoustic diodes.
Dual mechanisms of posttranscriptional regulation of Tet2 by Let-7 microRNA in macrophages
Authors: Jiang Shuai , Yan Wei , Wang Shizhen Emily , Baltimore David
Published: June 2019

Significance

Macrophages function as sentinel cells, constantly monitoring the host environment for bacterial infection. They are activated by bacterial components and then secrete proinflammatory cytokines, such as interleukin (IL)-6. This is one of the body’s most effective weapons for fighting infections but must be rigidly controlled to avoid pathologic overresponse. Many factors have been shown to act as feedback regulators of inflammatory processes. Using both knockout and myeloid cell-specific transgenic mouse models, we report here that a physiological role of the microRNA let-7adf cluster is to promote IL-6 secretion by lipopolysaccharide-activated macrophages through down-regulating Tet2. This microRNA cluster represses Tet2 using two different mechanisms: direct targeting and indirect enhancement of succinate accumulation, a compound that represses Tet2.
Economics of the disintegration of the Greenland ice sheet
Authors: Nordhaus William
Published: June 2019

Concerns about the impact on large-scale earth systems have taken center stage in the scientific and economic analysis of climate change. The present study analyzes the economic impact of a potential disintegration of the Greenland ice sheet (GIS). The study introduces an approach that combines long-run economic growth models, climate models, and reduced-form GIS models. The study demonstrates that social cost–benefit analysis and damage-limiting strategies can be usefully extended to illuminate issues with major long-term consequences, as well as concerns such as potential tipping points, irreversibility, and hysteresis. A key finding is that, under a wide range of assumptions, the risk of GIS disintegration makes a small contribution to the optimal stringency of current policy or to the overall social cost of climate change. It finds that the cost of GIS disintegration adds less than 5% to the social cost of carbon (SCC) under alternative discount rates and estimates of the GIS dynamics.
Mangroves shelter coastal economic activity from cyclones
Authors: Hochard Jacob P. , Hamilton Stuart , Barbier Edward B.
Published: June 2019

Significance

Mounting evidence suggests that mangrove forests protect coastal communities during tropical storm events. Yet, no large-scale analysis exists documenting these storm protection benefits globally. We provide global evidence that mangroves shelter economic activity during tropical cyclone exposure and that this sheltering prevents otherwise permanent losses to economic activity. These findings reveal that even modest mangrove forest coverage has the capacity to provide tremendous storm protection services, which highlights the need for mangrove conservation in many vulnerable coastal communities that have prior received less attention.
The Cdk1/Cdk2 homolog CDKA;1 controls the recombination landscape in
Arabidopsis
Authors: Wijnker Erik , Harashima Hirofumi , Müller Katja , Parra-Nuñez Pablo , de Snoo C. Bastiaan , van de Belt Jose , Dissmeyer Nico , Bayer Martin , Pradillo Monica , Schnittger Arp
Published: June 2019

Significance

Cyclin-dependent kinases are the main drivers of the mitotic cell cycle. Here, we show that the activity of the main cell-cycle regulator in the model plant Arabidopsis, CDKA;1, also governs one of the most important processes in meiosis: the formation of meiotic cross-overs. We show that CDKA;1 activity especially affects the major class of meiotic cross-overs, known as class I cross-overs. We find that lowering kinase activity leads to a progressive loss of cross-overs, of which cross-overs near the chromosome ends are the last to disappear. Conversely, an increase of kinase activity increases the rate of cross-over formation.
Regulation of
Caenorhabditis elegans
neuronal polarity by heterochronic genes
Authors: Armakola Maria , Ruvkun Gary
Published: June 2019

Significance

The pattern of synaptic inputs and outputs of neurons is established during development and is maintained throughout adulthood. An unknown set of cellular mechanisms establishes and maintains these synaptic connections. We used
Caenorhabditis elegans
to discover genes that act in the pathway of axodendritic polarity of a particular well-studied neuron, the cholinergic motorneuron DA9. We discovered that heterochronic genes regulate neuronal polarity during development and in postmitotic neurons in adults. This work reveals that developmental timing genes regulate the polarity of these
C.elegans
motor neurons. Understanding at a mechanistic level how neuronal polarity pathways are maintained in adulthood suggests potential strategies for therapeutic intervention in neurodegenerative diseases and models of cognitive decline in vivo.
Olfactory sensory neurons mediate ultrarapid antiviral immune responses in a TrkA-dependent manner
Authors: Sepahi Ali , Kraus Aurora , Casadei Elisa , Johnston Christopher A. , Galindo-Villegas Jorge , Kelly Cecelia , García-Moreno Diana , Muñoz Pilar , Mulero Victoriano , Huertas Mar , Salinas Irene
Published: June 2019

Significance

Many pathogens exploit the olfactory route to gain entry into the host. Olfactory sensory neurons (OSNs) are responsible for the detection of chemical stimuli in the environment but are also continuously exposed to microorganisms. Here, we report the interaction between crypt neurons (unique OSNs present in fish) and fish rhabdoviruses, an interaction that led to fast immune responses and the recruitment of nonconventional CD8 T cells to the olfactory mucosa from the olfactory bulb. These previously unrecognized antiviral immune responses required neuronal activation and depended on the interaction between the TrkA receptor expressed by crypt neurons and the viral glycoprotein protein. Our results show the importance of sensory neurons in sensing and controlling viruses that invade the nasal mucosa.
Boundary mode lubrication of articular cartilage with a biomimetic diblock copolymer
Authors: Sun Zhexun , Feeney Elizabeth , Guan Ya , Cook Sierra G. , Gourdon Delphine , Bonassar Lawrence J. , Putnam David
Published: June 2019

Significance

Lubricin is a glycoprotein that protects cartilage in weight-bearing joints under boundary mode conditions, which defines the conditions under which physical cartilage damage takes place. The natural expression of lubricin decreases with age, and when the joint is damaged. Replacement of lubricin by intraarticular injection reestablishes boundary mode lubrication and can protect against osteoarthritis. However, the manufacture of lubricin is difficult. We set out to create a synthetic mimetic of lubricin by mimicking its structure and functional composition. The result is a diblock copolymer that reduces the coefficient of friction on cartilage, under boundary mode conditions, to a level equivalent to native lubricin. This paper reports coefficents of friction in a boundary mode system that are equivalent to lubricin.
Hydrodynamics control shear-induced pattern formation in attractive suspensions
Authors: Varga Zsigmond , Grenard Vincent , Pecorario Stefano , Taberlet Nicolas , Dolique Vincent , Manneville Sébastien , Divoux Thibaut , McKinley Gareth H. , Swan James W.
Published: June 2019

Significance

Flows of particulate suspensions are ubiquitous in advanced technological applications, including coating of colloidal inks and paints, manufacturing of pharmaceuticals, and oil production. When particles aggregate due to attractive forces, flow can induce giant anisotropic concentration fluctuations. Surprisingly, shear flow between parallel plates organizes these fluctuations into periodically spaced, particle-rich stripes that are aligned perpendicularly to the flow direction. We use experiments and complementary simulations to build a universal stability criterion, demonstrating that hydrodynamic interactions alone drive this process of pattern formation independent of particle size, shape, and chemical composition. Such flow-induced patterning has potential applications in the production of a broad range of anisotropic structures for use in technologies such as flexible electronics and nanocomposites, 3D printing, and flow batteries.
Uncovering modern paint forgeries by radiocarbon dating
Authors: Hendriks Laura , Hajdas Irka , Ferreira Ester S. B. , Scherrer Nadim C. , Zumbühl Stefan , Smith Gregory D. , Welte Caroline , Wacker Lukas , Synal Hans-Arno , Günther Detlef
Published: June 2019

Significance

Can radiocarbon (
14
C) dating uncover modern forgeries? Radiocarbon dating has the potential to answer the question of when an artwork was created, by providing a time frame of the material used. In this study we show that with two microsamples (<500 μg), from both the canvas and the paint layer itself, a modern forgery could be identified. The canvas dating is consistent with the purported attribution to the 19th century; however, the
14
C age gained on the paint contradicts this as it offers clear evidence for a post-1950 creation. Thus the additional dating of the paint reveals the forger’s scheme where the repainting of an appropriately aged canvas was used to convey the illusion of authenticity.
The origins of specialized pottery and diverse alcohol fermentation techniques in Early Neolithic China
Authors: Liu Li , Wang Jiajing , Levin Maureece J. , Sinnott-Armstrong Nasa , Zhao Hao , Zhao Yanan , Shao Jing , Di Nan , Zhang Tian’en
Published: June 2019

In China, pottery containers first appeared about 20000 cal. BP, and became diverse in form during the Early Neolithic (9000–7000 cal. BP), signaling the emergence of functionally specialized vessels. China is also well-known for its early development of alcohol production. However, few studies have focused on the connections between the two technologies. Based on the analysis of residues (starch, phytolith, and fungus) adhering to pottery from two Early Neolithic sites in north China, here we demonstrate that three material changes occurring in the Early Neolithic signal innovation of specialized alcoholic making known in north China: (
i
) the spread of cereal domestication (millet and rice), (
ii
) the emergence of dedicated pottery types, particularly globular jars as liquid storage vessels, and (
iii
) the development of cereal-based alcohol production with at least two fermentation methods: the use of cereal malts and the use of moldy grain and herbs (
qu
and
caoqu
) as starters. The latter method was arguably a unique invention initiated in China, and our findings account for the earliest known examples of this technique. The major ingredients include broomcorn millet, Triticeae grasses, Job’s tears, rice, beans, snake gourd root, ginger, possible yam and lily, and other plants, some probably with medicinal properties (e.g., ginger). Alcoholic beverages made with these methods were named
li
,
jiu
, and
chang
in ancient texts, first recorded in the Shang oracle-bone inscriptions (ca. 3200 cal. BP); our findings have revealed a much deeper history of these diverse fermentation technologies in China.
Engineering the phototropin photocycle improves photoreceptor performance and plant biomass production
Authors: Hart Jaynee E. , Sullivan Stuart , Hermanowicz Paweł , Petersen Jan , Diaz-Ramos L. Aranzazú , Hoey David J. , Łabuz Justyna , Christie John M.
Published: June 2019

Significance

A key challenge for plant molecular biologists is to increase plant yield by altering photosynthetic productivity to secure food, energy, and environmental sustainability. In the model plant
Arabidopsis thaliana
, the plasma-membrane–associated phototropin kinases, phot1 and phot2, are activated by blue light and play important roles in regulating several responses that optimize photosynthetic efficiency. However, little effort has been made to target these pathways to increase plant growth. Here, we demonstrate that modifying the photocycle of phot1 and phot2 increases their sensitivity to light. Plants with these engineered phototropins exhibit more rapid and robust chloroplast movement responses and improved leaf positioning and expansion, leading to improved biomass accumulation under light-limiting conditions.
Adult sex ratio influences mate choice in Darwin’s finches
Authors: Grant Peter R. , Grant B. Rosemary
Published: June 2019

Significance

The adult sex ratio of populations is influenced by various social and environmental forces. When those forces result in an unequal sex ratio, the minority sex has greater reproductive opportunities than the majority sex. Here, we provide evidence of a flexible mating system of Darwin’s finches living in a fluctuating environment. Finches form social bonds that are monogamous, polygynous, or polyandrous, and also engage in extrapair mating (EPM). We show that unequal sex ratios are associated with extreme weather conditions, and they influence the frequency of changing mates within a breeding season and EPM. Results largely support the conclusions of comparative phylogenetic analyses, and provide insights into the early stages of evolutionary divergence from a presumed strictly monogamous mating system.
Qualifying insults, offensive epithets, slurs and expressive expletives
Authors: Cruz Manuel Padilla
Published: June 2019

The category of insults comprises disparaging qualifying terms, derogatory epithets, racial/ethnic slurs and participle-like expletives. All of them channel speakers’ (negative) psychological states, so they are considered expressives. Despite the enormous interest that they have aroused, research has not duly addressed whether all types of insults communicate in the same manner, share the same nature and make a similar contribution to communication. This paper ventures some answers from a relevance-theoretic perspective. Relying on theshowing-sayingcontinuum and on theconceptual-proceduraldistinction, it argues that some insults merely show speaker’s meaning, others encode some conceptual load enabling them to communicate by saying and others communicate by an admixture of both. It also contends that some insults encode conceptual content and processing instructions, but others encode instructions alone. Their output, however, is complex, as it may trigger lexical-pragmatic processes adjusting the encoded conceptual load or psychological-state representations.
Is fin-tech the new panacea for poverty alleviation and local development? Contesting Suri and Jack’s M-Pesa findings published in Science
Authors: Bateman Milford , Duvendack Maren , Loubere Nicholas
Published: June 2019

Financial technology, or simply ‘fin-tech’, is increasingly seen as one of the key tools to facilitate poverty reduction and local economic development. One article in particular by Tavneet Suri and William Jack published in the leading publication Science has played a hugely influential role in promoting the fin-tech model in the global South using the example of Kenya’s iconic M-Pesa money transfer platform. The authors’ central claim is that M-Pesa has been instrumental in facilitating a major episode of poverty reduction. Our analysis shows that their analysis and claims are extremely problematic.
Isotope harvesting at FRIB: additional opportunities for scientific discovery
Authors: Abel E Paige , Avilov Mikael , Ayres Virginia , Birnbaum Eva , Bollen Georg , Bonito Greg , Bredeweg Todd , Clause Hannah , Couture Aaron , DeVore Joe , Dietrich Matt , Ellison Paul , Engle Jonathan , Ferrieri Richard , Fitzsimmons Jonathan , Friedman Moshe , Georgobiani Dali , Graves Stephen , Greene John , Lapi Suzanne , Loveless C Shaun , Mastren Tara , Martinez-Gomez Cecilia , McGuinness Sean , Mittig Wolfgang , Morrissey David , Peaslee Graham , Pellemoine Frederique , Robertson J David , Scielzo Nicholas , Scott Matthew , Severin Gregory , Shaughnessy Dawn , Shusterman Jennifer , Singh Jaideep , Stoyer Mark , Sutherlin Logan , Visser Ate , Wilkinson John
Published: June 2019

The upcoming Facility for Rare Isotope Beams (FRIB) at Michigan State University provides a new opportunity to access some of the world’s most specialized scientific resources: radioisotopes. An excess of useful radioisotopes will be formed as FRIB fulfills its basic science mission of providing rare isotope beams. In order for the FRIB beams to reach high-purity, many of the isotopes are discarded and go unused. If harvested, the unused isotopes could enable new research for diverse applications ranging from medical therapy and diagnosis to nuclear security. Given that FRIB will have the capability to create about 80% of all possible atomic nuclei, harvesting at FRIB will provide a fast path for access to a vast array of isotopes of interest in basic and applied science investigations. To fully realize this opportunity, infrastructure investment is required to enable harvesting and purification of otherwise unused isotopes. An investment in isotope harvesting at FRIB will provide a powerful resource for development of crucial isotope applications. In 2010, the United States Department of Energy Office of Science, Nuclear Physics, sponsored the first ‘Workshop on Isotope Harvesting at FRIB’, convening researchers from diverse fields to discuss the scientific impact and technical feasibility of isotope harvesting. Following the initial meeting, a series of biennial workshops was organized. At the fourth workshop, at Michigan State University in 2016, the community elected to prepare a formal document to present their findings. This report is the output of the working group, drawing on contributions and discussions with a broad range of scientific experts.
Nanosecond plasmas in water: ignition, cavitation and plasma parameters
Authors: Grosse K , Held J , Kai M , von Keudell A
Published: June 2019

Nanosecond plasmas in liquids play an important role in the field of decontamination, electrolysis or plasma medicine. The understanding of these very dynamic plasmas requires information about the temporal variation of species densities and temperatures. This is analyzed by monitoring nanosecond pulsed plasmas that are generated by high voltages (HVs) between 14 and 26 kV and pulse lengths of 10 ns applied to a tungsten tip with 50 μm diameter immersed in water. Ignition of the plasma causes the formation of a cavitation bubble that is monitored by shadowgraphy to measure the dynamic of the created bubble and the sound speed of the emitted acoustic waves surrounding this tungsten tip. The temporal evolution of the bubble size is compared with cavitation theory yielding good agreement for an initial bubble radius of 25 μm with an initial pressure of 5 × 108 Pa at a temperature of 1200 K for a HV of 20 kV. This yields an initial energy in the range of a few 10−5 J that varies with the applied HV. The dissipated energy by the plasma drives the adiabatic expansion of water vapor inside the bubble from its initial supercritical state to a low pressure, low temperature state at maximum bubble expansion reaching values of 103 Pa and 50 K, respectively. These predictions from cavitation theory are corroborated by optical emission spectroscopy. After igniting the nanosecond plasma, the electrical power oscillates in the feed line between HV pulser and plasma chamber with a ring down time of the order of 60 ns. These reflected pulses re-ignite a plasma inside the expanding bubble periodically. Broadband emission due to recombination and Bremsstrahlung becomes visible within the first 30 ns. At later times, line emission dominates. Stark broadening of the spectral lines of H
α
(656 nm) and OI (777 nm) is evaluated to determine both the electron density and the electron temperature in these re-ignited plasmas.
Proton transfer reaction time-of-flight mass spectrometric measurements of volatile compounds contained in peppermint oil capsules of relevance to real-time pharmacokinetic breath studies
Authors: Malásková Michaela , Henderson Ben , Chellayah Prema D , Ruzsanyi Veronika , Mochalski Paweł , Cristescu Simona M , Mayhew Chris A
Published: June 2019

With the growing interest in the use of breath volatiles in the health sciences, the lack of standardization for the sampling and analysis of exhaled breath is becoming a major issue leading to an absence of conformity, reproducibility and reliability in spectrometric measurements. Through the creation of a worldwide ‘peppermint consortium’, the International Association of Breath Research has set up a task force to deal with this problem. Pharmacokinetic studies are proposed, and a real-time analytical technique that is being used is proton transfer reaction-time-of-flight-mass spectrometry (PTR-ToF-MS). This paper presents details on how the volatile compounds contained in a peppermint oil capsule, and hence on breath, appear in a PTR-ToF-MS. To aid that study, the key volatiles in the headspace of peppermint oil were first identified using gas chromatography-mass spectrometry, notably: menthol, menthone, 1,8-cineole, menthofuran, limonene, α-pinene and β-pinene. A PTR-ToF-MS analysis of these compounds has been undertaken, divorced from the complexity of the peppermint oil matrix using ‘normal’ and ‘saturated’ humidity drift-tube conditions, with the latter used to mimic breath samples, and over a range of reduced electric fields. There are no characteristic product ions that can distinguish monoterpenes and 1,8-cineole, and hence, without pre-separation, a combined washout for these volatiles can only be provided. By operating the drift tube above about 130 Td, there are characteristic product ions for menthone, menthofuran and menthol, namely m/z 155.14 (protonated menthone), m/z 151.11 (protonated menthofuran), m/z 139.15 (loss of H2O from protonated menthol) and m/z 83.09 (a fragment ion, C6H11
+, from menthol). These have been used to monitor, with a high specificity, the temporal profile of these three compounds in breath following the ingestion of a peppermint oil capsule. To aid in the analyses, the proton affinities and gas-phase basicities for the key volatiles investigated have been determined using density functional theory.
Research Status and Control Measures of Transverse Cracks for Micro-alloyed Continuous Casting Billet
Authors: Li Qi , Wu Jian , Bao Li , Gu Yu
Published: June 2019

The transverse cracks of the micro-alloyed steel continuous casting billet seriously damage the quality of the continuous casting billet and cause great losses to the enterprise. The influence of the hot ductility, microstructure, and micro-alloying elements on transverse crack was discussed, which has been researched in-depth at home and abroad. Through a great deal of studies, various control measures of transverse crack are proposed, such as secondary cooling technology, chamfering mold, refining the surface structure of the casting slab, and double phase transformation process. However, the transverse cracks have not been fundamentally solved. Therefore, the formation mechanism and control measures of the transverse crack are summarized for providing with the idea of eliminating transverse crack.
Fabrication of Micro-Hole Array on Glass Material by Abrasive Jet Machining
Authors: Chao Choung-Lii , Wang Wan-Hsuan , Chao Tian-Ming , Chou Wen-Chen , Ma Kung-Jeng
Published: June 2019

Brittle materials such as glasses, silicon, and silicon carbide are normally categorized as difficult to machine materials for its high hardness and brittleness. However, they have attracted more and more attentions and been playing critical roles in many scientific/engineering applications for their advanced physic/optical/electronic properties. Micro-patterns such as micro-holes (array) of various sizes and shapes are frequently required to be generated on brittle materials. Many researchers have tried different approaches such as laser ablation, ultrasonic machining, and rotary ultrasonic machining to produce micro-holes in brittle materials. This research applied abrasive jet machining to fabricate micro-holes array on glass. Efforts have been made to investigate the effect of grit-size, stand-off distance, pressure on the material removal rate and the obtained holes accuracy. Micro-hole arrays of various shapes and with characteristic dimension ranging from 0.2 mm to 2 mm are successfully produced in glass plate of 0.4 mm thickness.
Aluminium Lined, Carbon Composite Overwrapped Pressure Vessel
Authors: Mujaheed Yunusa , Lei Zu , Dan Chen , Robert Tapa Arnauld
Published: June 2019

A numerical analysis of filament-reinforced internally pressurized cylindrical vessel with over-wrapped metallic liner is presented, the study deals with simulation of aluminium liner pressure vessel overwrapping by composite T800/epoxy was selected, ABAQUS Software was use in which 20 layers of composite were analysed. The stress state of the pressure vessel under the internal pressure of 33MPa was analysed, and the bursting strength was predicted to be 92.3MPa. MATLAB software was used to simulate the winding process, the 5 axis numerical control winding machine was used for the actual winding, and the fibres were arranged in a regular and uniform way, and the sliding phenomenon was not occurred. After solidifying, the bursting strength was 85.4MPa, and the difference between the actual value and the predicted value was 6.9%. The experimental results were in good agreement with the simulation results.
Characteristics of RF Magnetron Sputtered VO2 Thin Films for Potential Applications of Solar Control Coatings
Authors: Muslim Noormariah , Soon Ying Woan , Voo Nyuk Yoong
Published: June 2019

Properties of vanadium dioxide or vanadia (VO2) thin films prepared using radio frequency (RF) magnetron sputtering with a pure VO2 target were analysed. The properties consisted of crystal structure, surface topography, surface morphology as well as optical and thermochromic properties of VO2 thin films. The deposition was conducted in an argon atmosphere of flow rate of 30 sccm, substrate temperature of 500 °C and RF sputtering power of 100 W. The film, which was deposited with film thickness of 50 nm, exhibited a single orientation of (110) orientation. The film surface featured quite homogeneous and continuous surface topography, and spherical-like grains that represented grains in VO2(M) phase. The film had low surface roughness resulting in quite high optical transmittance and relatively low optical reflectance, at room temperature throughout visible and near-infrared regions. Meanwhile, the film also showed a phase transition at ∼65.0 °C with hysteresis width of 38 °C.
Very High Cycle Fatigue Behaviour of the 316L Weldment Fabricated By Laser Butt-Welding
Authors: Xiong Z H , Ma X F , Qi X Y
Published: June 2019

In nuclear industry, 316L weldments are widely used in components fabricating, which usually suffer from very-high-cycle fatigue. Therefore, the very high cycle fatigue (VHCF) behaviour of 316L weldment fabricated by laser butt-welding joint were studied using an ultrasonic fatigue testing system. The microscopic examination indicated that an evident pore is observed in the weld seam and the fine columnar-dendrite structure is formed in the central part of the weld seam. Near the weld interface in the weld seam, the weld microstructure shows larger columnar-dendrite. The hardness distribution of the weldment is to coincide with the characteristic of the microstructure. In the central part of the weld seam, the hardness is the highest, and is the lowest in the base metal. Fatigue failure still occurred in the VHCF regime. The fatigue crack initiated from the internal pores caused by laser butt-welding. Although the fatigue strength of weld seam might be decreased due to the pore, the fatigue strength of the weldment was the same as the base metal in this research. That is, the defect with a certain size in the weld seam does not affect the strength of the weldment.
Numerical Simulation Analysis of Surfacing Temperature Field of Pulling-straightening Roller
Authors: Luyang Jie , Hua Chen , Liyan Wang
Published: June 2019

In this paper, the ANSYS software thermal analysis is used to simulate the 0Cr13Ni4MoN surfacing process of the pulling-straightening roller. The Gaussian model was selected as the heat source model, and the direct solution method was used to calculate the temperature field of the surfacing process. The effects of preheating temperatures of 250°C, 300°C and 350°C on the temperature field of the pulling-straightening roller were discussed. The results show that the preheating temperature range of 250∼350°C gives a uniform temperature field.
Optimization Techniques and Multi-Objective Analysis in Hybrid Solar-Wind Power Systems for Grid-Connected Supply
Authors: Alaaeddin M. H. , Zakaria A. , Jani J.M. , Seyajah N.
Published: June 2019

Renewable energy has become a vital source for generating electricity, mitigating greenhouse gas emissions, and eliminating the reliance on non-renewable forms of energy. This work highlights on the urgent need for clean, efficient, and resilient energy sources through the development of advanced optimization methods. The hybrid solar-wind systems are meant to maximize power generation. Complexity arises when determining the optimum design, size, functionality, materials, distribution, and mechanism of each system as they are combined to ensure system reliability and optimal outcomes. The development of the new optimization methods (such as genetic algorithms, heuristic approaches, and particle swarm techniques) was generated to overcome the encountered barriers in traditional or classical approaches; such as in iterative techniques and linear programming methods. Additionally, the multi-objective analysis has been involved in various studies where vectors, criteria, and alternatives are applied with respect to the main objectives. However, further research efforts are encouraged to innovatively optimize hybrid solar-wind systems; including the optimization of hybrid solar-wind sizing (HSWS), design, capacity, battery storage, energy distribution systems and techno-economical considerations.
Design, Modeling and Analysis of a XY Nanopositioning Stage for High Speed Scanning
Authors: Lin Shenglong , Zhang Xianmin , Zhu Benliang
Published: June 2019

In order to increase the imaging speed of scanning probe microscopy (SPM), especially atomic force microscopy (AFM) where needs a high-bandwidth moving stage possessing high resonant frequency and low cross-coupling, the paper proposes a kind of XY nanopositioning stage achieving about 10kHz resonant frequency, 15um×15um workspace and well decoupled performance. Considering the design objective, a compliant nanopositioning stage is built with doubly clamped beam and parallelogram hybrid beam for overcoming the problem of low natural frequency and cross-coupling performance. By establishing mathematical model of the proposed stage including stiffness model and resonant frequencies model, the paper solves the highest natural frequency with its optimal dimensions of beams by applying optimization. Finally the designed stage is imported to Workbench for the validation of mathematical model by simulation, where presents the FEA results can nicely match the analytical results.