bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterisation of the high strain rate behaviour of tubular materials
Authors: Caisso Camille , Jacques Nicolas , El Malki Alaoui Aboulghit , Fresnel Harold , Demmouche Younes
Published: September 2018

Airbag gas generators used in the automotive industry are often fabricated from tubular materials. The present work deals with the development of split Hopkinson tensile bar (SHTB) tests for tubular samples. Tubular specimens were machined from the tubes. A specific gripping system was designed to install the samples between the incident and transmitter bars. The forces acting on the samplegrip assembly were measured using strain gages mounted on the bars. Strain gages were also placed on the specimen in order to obtain the local strain history. Finite element computations were carried out to assess the validity of the experimental setup. It was observed that, in some cases, a vibration of the gripping system may induce oscillations on the force signals. To limit this phenomenon, pulse shapers [1] were employed in order to obtain a smoother input wave. Several tests were performed for different impact velocities. Strain rates ranging between 100 and 700 s-1 were achieved. Quasi-static tensile tests were also carried out. From the results of the different experiments, it was found that the steel under investigation has significant strain-rate sensitivity. Using inverse analysis, parameters for the Zerilli-Armstrong constitutive model [2] were identified.
Experiment and finite element analysis of U-profile subjected to dynamic loading
Authors: Rund Martin , Mašek Martin , Džugan Jan , Konopík Pavel , Janovec Jiøí
Published: September 2018

The presented study deals with the FEM simulation of dynamic behaviour of U-profile crash under three point bent loading conditions verified by experimental investigations. The material ductile damage behaviour under wide strain rate region covering 0.001 – 1 000 s-1 was experimentally determined with the use of standard and micro tensile tests (M-TT). DIC systems were used for strain field measurements under quasi-static and dynamic loading conditions. Based on these experimental data, material model considering ductile damage was established in Abaqus/Explicit code. Additionally, also metallographic investigations were performed for the fracture behaviour description.
Strain rate influence on mechanical behavior of a single wire entangled material
Authors: Guérard Sandra , Girardot Jérémie , Viot Philippe
Published: September 2018

In a global context of energy saving, the ratio stiffness – mass is a key parameter for design of mechanical structures. To deal with this major concern, sandwich materials are finding an increasing use: the skins are designed to resist tensile and compressive stresses while the core needs to gather lightweight, shear stresses resistance and high mechanical energy absorption capacities. Firstly made of balsa wood, the core is nowadays classically realized using architectured materials (cellular materials, honeycombs, entangled materials, etc.). Entangled materials are architectured materials with tuneable properties, depending of the dedicated application. Several entangled materials already exist such as mineral or metallic wool; some of them are made of a single ductile metallic wire, entangled in all directions so that the final material becomes a porous continuous media. Such materials, which combine lightness and ductile behaviour, seem to be perfect candidates to dissipate energy during an impact. Compared to conventional materials such as balsa wood or honeycomb, a large amount of energy is indeed dissipated by friction coming from the numerous contacts due to the entanglement. The global aim of this work is focused on the study of energy dissipation mechanisms involved during impact as well as the correlation between architectural parameters of the material (wire diameter and material, volume fraction, etc.) and macroscopic behaviour. The first step that is presented here consists of an experimental investigation using dynamic compression tests to study macroscopic parameters (wire diameter, volume fraction, etc.) on absorbed energy.
Structure / Property (Constitutive and Dynamic Strength / Damage) Behavior of Additively Manufactured Tantalum
Authors: Gray George.T. , Livescu Veronica , Knapp Cameron , Jones David R. , Fensin Saryu , Chen Shuh-Rong , Cady Carl M. , Trujillo Carl P. , Martinez Daniel
Published: September 2018

For Certification and qualification of an engineering component generally involves meeting engineering and physics requirements tied to its functional requirements. In this paper, the results of a study quantifying the microstructure, mechanical behavior, and the dynamic damage evolution of Tantalum (Ta) fabricated using an EOS laser-powder-bed machine are presented. The microstructure and quasi-static mechanical behavior of the AM-Ta is detailed and compared / contrasted to wrought Ta. The dynamic damage evolution and failure response of the AM-Ta material, as well as wrought Ta, was probed using flyer-plate impact driven spallation experiments. The differences in the spallation response between the AM and wrought Ta were measured using in-situ velocimetry as well as post-mortem quantification of damage in “soft-recovered” samples. The damage evolution of the AM and wrought Ta were characterized using both optical metallography and electron-backscatter diffraction.
Deformation mechanisms and microplasticity of austenitic TRIP/TWIP steel under flyer plate impact
Authors: Eckner Ralf , Krüger Lutz , Motylenko Mykhaylo , Savinykh Andrey S. , Razorenov Sergey V. , Garkushin Gennady V.
Published: September 2018

Abstract. The focus of this study is on the deformation mechanisms of high-alloy cast austenitic TRIP/TWIP steel with the nominal composition Fe-16Cr-6Mn-6Ni. Due to its chemical composition, the material exhibits a low stacking-fault energy of 17.5 mJ/m2which facilitates the formation of the deformation-induced γ (fcc) → ε (hep) → α’ (bcc) transformation. Consequently, the steel exhibits a tensile strength of 800 MPa with fracture elongation of 55 % under quasi-static loading. The experiments presented demonstrate the response of this steel to flyer-plate impact (FPI) at room temperature using two different test setups. In the first setup, laser interferometry measurements of the sample free surface were used for determination of the dynamic mechanical properties (Hugoniot elastic limit / HEL. spall strength) after impact with aluminium plates accelerated up to 650 m/s. In the second setup, an experimental shock testing device developed at the Freiberg High-Pressure Research Centre was used for impacting large cylindrical samples without the occurrence of spallation. Subsequently, microstructural investigations were carried out by scanning electron microscopy (SEM) and transmission election microscopy (TEM) in combination with diffraction techniques and magnetic martensite measurements. Their results facilitate the representation of a complete image of deformation mechanisms during shock wave loading.
Stress and Strain Rate Effects on Incipient Spall in Tantalum
Authors: Jones David R. , Fensin Saryu J. , Trujillo Carl P. , Martinez Daniel T. , Gray George T.
Published: September 2018

Spall fracture is a high-rate tensile damage phenomenon associated with impulsive and shock-load events. Typically, the material undergoes a sequence of compression followed by release into high rate (on the order of 104 s-1 and up) tension, causing voids to nucleate and grow, which can then coalesce into a crack and the material fails. We present a series of experiments on high purity, well characterized tantalum samples subjected to shock-loading via gas-gun plate impact. Through careful selection of the flyer-plate velocity and material we have independent control over the peak compressive stress and the tensile strain rate in the sample. At all times, the spall damage remains incipient, i.e. in the early stages of void formation and the material does not fully fracture. Velocimetry was used on the rear of the sample to record the wave-profiles and determine spall strength. Soft recovery and sectioning of the samples allowed the internal damage to be observed, quantifying the damage amount, distribution, and relationship to microstructural features with both optical and electron based microscopy.
Mechanical properties and strain rate sensitivity of 3D laserdeposited Ti-6Al-4V alloy
Authors: Woo Sanghyun , Lee Yerim , Park Leeju
Published: September 2018

Ti-6Al-4V has become the most common material in titanium alloy. Due to High specific strength, low density and excellent mechanical properties, it has been used in not only living, sports goods but also aerospace, defense industries. Usually these products have complex geometry, so there are a lot of limitations in general manufacturing process. Especially in weapon systems, applied loadings are severe therefore choice of materials is very important. 3D printing method is useful for manufacturing these complicated structure and suitable to discontinued, superannuated part of products. In this study, specimen for experiments is turned out by using 3d laser deposition technology which metal powder is injected into the focused beam of a high-powered laser. While lots of studies are mainly concerned with normal process, it is not commonly researched for metallic materials forming through 3D printing. In the 10-3~103/s strain rates range, two kinds of plate samples and LDAM Ti-6Al-4V were performed using universal testing machine and SHPB for dynamic material properties. Simplified Johnson-Cook constitutive equation parameters produced from these experiments.
Response of UHPFRCs in Tension under High Stress Rate
Authors: Dobruský Svatopluk , Forni Daniele , Cadoni Ezio
Published: September 2018

The paper presents a part of a full-experimental campaign characterizing various Ductal® mix designs (compressive strength of 150, 170, 210MPa) with various dosages of fibers (2% and 3.25%). The dynamic tests are performed by means of two Modified Hopkinson Bar devices with that are installed at the DynaMat Laboratory in Lugano. The tests, in tension at different velocities were performed on cylindrical notched specimens of 60mm in diameter and 60mm height (notch/radius = 0.20). The preliminary results present different rate sensitivity of the materials. Different behaviours are registered for the materials having matrix with special thermal curing respect to those cured as usual. An important increment of stress was obtained for the matrix where sand was partially replaced by Silica Fume. These results are the base for better understanding the mechanical behaviour in dynamic that will be obtained by further tests on Ultra-High Performance Fibre-Reinforced Concretes (various Ductal® classes). Such data will provide designers better overview of relevant properties of these materials for design of protective structures.
Impact Tensile Properties of Notched Titanium Alloy Bolt for Fairing Separation of Launch Vehicle
Authors: Shimanuki Hiroto , Yamada Hiroyuki , Kami Tsuyoshi , Yamasaki Yoshihiro , Ikaida Hiroshi , Kamita Toru , Amakawa Hiroaki , Nishimoto Miki , Kobayashi Hidetoshi
Published: September 2018

The payload fairing in Japan is fixed by a lot of notched bolts. These notched bolts were fractured by axial impact tensile using the explosive devices to separate the fairing. In this case, the stress waves and the oscillations propagate, which may seriously damage the satellites. In this study, the impact deformation and the fracture behavior of notched titanium alloy bolt was investigated using a split Hopkinson pressure bar method. The notched bolt specimen was made of commercial Ti-6Al-4V alloy. The maximum load value was increased with increasing the displacement rate. It can be said that the strain rate dependence of strength for Ti-6Al-4V alloy appeared. From the observation of fracture surface using a scanning electron microscope, compared with the quasi-static test, it was clear that the irregularities of the fractured surface at the impact tensile test became rough. Therefore, it was found that the brittle fracture was mainly observed due to the increase in displacement rate, which may mean that the mode of fracture changes from the transgranular to the intergranular. It was surmised that this change of fracture mode was caused by the high strain rate due to stress concentration of the notched part.
Temperature and strain rate dependent mechanical response of METCO 601 aluminium-polyester abradable seal coating
Authors: Pellegrino Antonio , Perez-Martin Maria Jesus , Dragnevski Kalin , Zumpano Giuseppe , Petrinic Nik
Published: September 2018

Abradable coatings are utilised as sacrificial materials in low-pressure compressor casings, and in intermediate and high pressure compressors and seals. The adoption of abradable coatings allows for the clearance between compressor blades and casing to be minimised, increasing the overall efficiency of the engine. Quasi-static and dynamic experiments at different temperatures are conducted to characterise the mechanical response of a thermally-sprayed abradable seal coating. The material is composed of an aluminium continuum matrix and fairly well-dispersed polyester particles. Stress versus strain histories are measured in uniaxial tension and compression at strain rates ranging from 10-3 to 102 s-1, via non-standard experimental techniques. The material displays sensitivity to the strain rate and to the imposed temperature. The mechanical behaviour is brittle in tension while it exhibits higher strains to failure in compression. The material is characterised by a pronounced tension/compression asymmetry.
Increased Frequency of Skin-to-Skin Contact Is Associated with Enhanced Vagal Tone and Improved Health Outcomes in Preterm Neonates
Authors: Marvin Megan , Gardner Fumiyuki , Sarsfield Kristin , Travagli R. , Doheny Kim
Published: September 2018

Objective An estimation of the individual's ability to cope with environmental adversity, that is, stress resiliency, can be extrapolated by measuring cardiac vagal tone, that is, high-frequency heart rate variability (HF-HRV); indeed, higher HF-HRV is associated with health and developmental advantages for preterm neonates. Previous studies show skin-to-skin contact (SSC) improves stress resiliency; however, linkages between SSC and HF-HRV on outcomes have not been assessed. We aimed to test the hypothesis that increased SSC frequency would enhance HF-HRV, reduce neonatal morbidity, and improve developmental outcomes.

Study Design Weekly electrocardiograms and clinical data were obtained from 101 preterm neonates. SSC frequency was determined from the electronic medical record.

Results At postnatal week 1, frequency of SSC and HF-HRV were positively correlated (p =.02); further, multiple stepwise regressions showed higher HF-HRV and SSC predicted reduced days on ventilation and oxygen, and shorter hospital stay (p < 0.001). Higher HF-HRV predicted lower postmenstrual age (PMA) at discharge (p < 0.01).

Conclusion Higher SSC frequency was associated with increased HF-HRV during the first postnatal week. SSC and HF-HRV uniquely predicted diminished neonatal morbidity throughout hospitalization. Additionally, HF-HRV uniquely predicted earlier PMA at discharge. Augmenting SSC early in life enhances stress resiliency and improves health outcomes.
Clinical Diagnosis of Placenta Accreta and Clinicopathological Outcomes
Authors: Hirshberg Jonathan , Stout Molly , Cahill Alison , Macones George , Tuuli Methodius , Rosenbloom Joshua
Published: September 2018

Objective To investigate the association between the intraoperative diagnosis of placenta accreta at the time of cesarean hysterectomy and pathological diagnosis.

Study Design This is a retrospective cohort study of all patients undergoing cesarean hysterectomy for suspected placenta accreta from 2000 to 2016 at Barnes-Jewish Hospital. The primary outcome was the presence of invasive placentation on the pathology report. We estimated predictive characteristics of clinical diagnosis of placenta accreta using pathological diagnosis as the correct diagnosis.

Results There were 50 cesarean hysterectomies performed for suspected abnormal placentation from 2000 to 2016. Of these, 34 (68%) had a diagnosis of accreta preoperatively and 16 (32%) were diagnosed intraoperatively at the time of cesarean delivery. Two patients had no pathological evidence of invasion, corresponding to a false-positive rate of 4% (95% confidence interval [CI]: 0.5%, 13.8%) and a positive predictive value of 96% (95% CI: 86.3%, 99.5%). There were no differences in complications among patients diagnosed intraoperatively compared with those diagnosed preoperatively.

Conclusion Most patients undergoing cesarean hysterectomy for placenta accreta do have this diagnosis confirmed on pathology. However, since the diagnosis of placenta accreta was made intraoperatively in nearly a third of cesarean hysterectomies, intraoperative vigilance is required as the need for cesarean hysterectomy may not be anticipated preoperatively.
Strukturierte Gewichtsreduktionsprogramme bei Adipositas: Welches Angebot für welchen Patienten!?
Authors: Keuthage W. , Schoppe T.
Published: September 2018

Zweifelsohne ist die Epidemie der Adipositas eine der Herausforderungen der kommenden Jahre und Jahrzehnte. In Deutschland stehen Adipösen aktuell keine flächendeckenden Therapieangebote zur Verfügung. Hauptgrund ist, dass Krankenkassen sich nur eingeschränkt und regional sehr unterschiedlich an den Kosten von Lebensstilprogrammen beteiligen. Der optionale Einsatz von Formulaprodukten und/oder telemedizinischen Angeboten kann helfen, die Versorgung Adipöser zu verbessern. Hierbei kommt sowohl die Entwicklung neuer Konzepte als auch die Erweiterung bereits etablierter Programme, wie z.B. DOC WEIGHT®, in Frage. Kostenträger verlangen – zu Recht – die Evaluation von Therapieprogrammen. Hierzu muss im Vorfeld die Finanzierung der Adipositastherapie sichergestellt werden. Werden mehrere Lebensstilprogramme parallel in einer Praxis angeboten, hat der Patient die Möglichkeit, das für ihn passende Programm auszuwählen. Im besonderen Maß profitieren Menschen mit
Typ-2-Diabetes von einem solchen Angebot. Insbesondere diabetologischen Schwerpunktpraxen bietet sich die Möglichkeit, ihr bisheriges Leistungsspektrum auszuweiten und die Versorgung ihrer Patienten zu verbessern.
A coupled focusing-defocusing complex short pulse equation: Multisoliton, breather, and rogue wave
Authors: Yang Jun , Zhu Zuo-Nong
Published: September 2018

Nonlinear Schrödinger equation, short pulse equation, and complex short pulse equation have important applications in nonlinear optics. They can be derived from the Maxwell equations. In this paper, we investigate a coupled focusing-defocusing complex short pulse equation. The bright-bright, bright-dark, and dark-dark soliton solutions of the coupled focusing-defocusing complex short pulse equation are constructed. Furthermore, the breather solutions are derived from the dark soliton solution. The rogue wave solutions are also constructed. The dynamics and the asymptotic behavior of the soliton solutions are analyzed, which reveals a fact that the bright-bright soliton collision can be either elastic or inelastic, but the bright-dark and dark-dark soliton collision can only be elastic.
Numerical investigation of a solar air heater comprising longitudinally finned absorber plate and thermal energy storage system
Authors: Josyula Tejaswi , Singh Satyender , Dhiman Prashant
Published: September 2018

In the present work, the thermal performance of a double glazed single pass solar air heater consisting of a longitudinally finned absorber plate on its top surface and attached to a phase change material (PCM) with its bottom surface is investigated, theoretically. Paraffin wax (Rubitherm RT42) is used as a PCM. The main idea of this solar air heater design is to use it during nocturnal hours or off sunshine hours. A computational heat transfer and fluid dynamics solution using an implicit scheme has been developed and employed to study the effects of the mass flow rate and number of fins on its thermal performance under transient conditions. The maximum outlet air temperature of the finned type solar air heater with latent heat storage is achieved as 40 °C, 37 °C, and 35 °C for mass flow rates of 0.01, 0.015, and 0.02 kg/s, respectively, and it is predicted that the system can be used for 14, 12, and 10 h after sunset at respective mass flow rates. The maximum daily average thermal efficiency is predicted to be 62.4% at a mass flow rate of 0.02 kg/s which is higher than the other designs considered in the present investigation.
An open and flexible digital phase-locked loop for optical metrology
Authors: Tourigny-Plante Alex , Michaud-Belleau Vincent , Bourbeau Hébert Nicolas , Bergeron Hugo , Genest Jérôme , Deschênes Jean-Daniel
Published: September 2018

This paper presents an open and flexible digital phase-locked loop optimized for laser stabilization systems. It is implemented on a cheap and easily accessible FPGA-based digital electronics platform (Red Pitaya) running a customizable open-source firmware. A PC-based software interface allows controlling the platform and optimizing the loop parameters remotely. Several tools are included to allow measurement of quantities of interest smoothly and rapidly. To demonstrate the platform’s capabilities, we built a fiber noise canceller over a 400 m fiber link. Noise cancellation was achieved over a 30 kHz bandwidth, a value limited mainly by the delays introduced by the actuator and by the round-trip propagation over the fiber link. We measured a total latency of 565 ns for the platform itself, limiting the theoretically achievable control bandwidth to approximately 225 kHz.
Cryo scanning transmission x-ray microscope optimized for spectrotomography
Authors: Leontowich A. F. G. , Berg R. , Regier C. N. , Taylor D. M. , Wang J. , Beauregard D. , Geilhufe J. , Swirsky J. , Wu J. , Karunakaran C. , Hitchcock A. P. , Urquhart S. G.
Published: September 2018

A cryo scanning transmission X-ray microscope, the cryo-STXM, has been designed and commissioned at the Canadian Light Source synchrotron. The instrument is designed to operate from 100 to 4000 eV (λ = 12.4 − 0.31 nm). Users can insert a previously frozen sample, through a load lock, and rotate it ±70° in the beam to collect tomographic data sets. The sample can be maintained for extended periods at 92 K primarily to suppress radiation damage and a pressure on the order of 10−9 Torr to suppress sample contamination. The achieved spatial resolution (30 nm) and spectral resolution (0.1 eV) are similar to other current soft X-ray STXMs, as demonstrated by measurements on known samples and test patterns. The data acquisition efficiency is significantly more favorable for both imaging and tomography. 2D images, 3D tomograms, and 4D chemical maps of automotive hydrogen fuel cell thin sections are presented to demonstrate current performance and new capabilities, namely, cryo-spectrotomography in the soft X-ray region.
Research on the selective adhesion characteristics of polydimethylsiloxane layer
Authors: Ye Xiangdong , Cai Dongbao , Ruan Xiaoguang , Cai Anjiang
Published: September 2018

Polydimethylsiloxane (PDMS) is a widely used inexpensive, non-toxic material which has many advantages. But it is generally considered that PDMS does not adhere to the other substrates without the special treatments due to its low surface energy. However, in this paper, it is the first time that we found that the PDMS adhered on the silicon dioxide substrate to form an adhesive layer only by the routine cast molding process. The mechanism of the PDMS adhesion on the silicon dioxide substrate during the process was illustrated in detail. The smooth, thin, transparent, hydrophobic and selective PDMS adhesion layer can be used as a functional coating to improve the special performances of the micro/nano devices. Finally, as an example, a facile approach is proposed to realize the superhydrophobic surfaces by combining the SiO2 microstructure with the PDMS adhesion layer.
Two-photon imaging assisted by a thin dynamic scattering layer
Authors: Hong Peilong
Published: September 2018

We propose a two-photon imaging scheme with a thin dynamic scattering layer as the crucial imaging element. The constructive two-photon interference for direct imaging is built when the object is properly illuminated by an entangled two-photon source. We show that the proposed imaging scheme can be used for imaging an amplitude object with incoherent two-photon illumination, and the resolution reaches Heisenberg limit. Besides, the imaging for a phase object can also be achieved in the proposed imaging scheme with coherent two-photon illumination.
Epitaxial stabilization of pulsed laser deposited Srn+1IrnO3n+1 thin films: Entangled effect of growth dynamics and strain
Authors: Gutiérrez-Llorente Araceli , Iglesias Lucía , Rodríguez-González Benito , Rivadulla Francisco
Published: September 2018

The subtle balance of electronic correlations, crystal field splitting, and spin–orbit coupling in layered Ir4+ oxides can give rise to novel electronic and magnetic phases. Experimental progress in this field relies on the synthesis of epitaxial films of these oxides. However, the growth of layered iridates with excellent structural quality is a great experimental challenge. Here we selectively grow high quality single-phase films of Sr2IrO4, Sr3Ir2O7, and SrIrO3 on various substrates from a single Sr3Ir2O7 target by tuning background oxygen pressure and epitaxial strain. We demonstrate a complex interplay between growth dynamics and strain during thin film deposition. Such interplay leads to the stabilization of different phases in films grown on different substrates under identical growth conditions, which cannot be explained by a simple kinetic model. We further investigate the thermoelectric properties of the three phases and propose that weak localization is responsible for the low temperature activated resistivity observed in SrIrO3 under compressive strain.
Optical lattices with higher-order exceptional points by non-Hermitian coupling
Authors: Zhou Xingping , Gupta Samit Kumar , Huang Zhong , Yan Zhendong , Zhan Peng , Chen Zhuo , Lu Minghui , Wang Zhenlin
Published: September 2018

Exceptional points (EPs) are degeneracies in open wave systems with coalescence of at least two energy levels and their corresponding eigenstates. In higher dimensions, more complex EP physics not found in two-state systems is observed. We consider the emergence and interaction of multiple EPs in a four coupled optical waveguides system by non-Hermitian coupling showing a unique EP formation pattern in a phase diagram. In addition, absolute phase rigidities are computed to show the mixing of the different states in definite parameter regimes. Our results could be potentially important for developing further understanding of EP physics in higher dimensions via generalized paradigm of non-Hermitian coupling for a generation of parity-time devices.
Particle simulation of a magnetized plasma sheath with the magnetic field parallel to the wall
Authors: Li Dehui , Wang Shaojie
Published: September 2018

The plasma sheath in a magnetic field parallel to the wall is studied by particle in cell simulations. The simulation results show that the spatial structure of the sheath is determined by the ion Debye length, instead of the ion Larmor radius or the electron Debye length. The characteristic time of the magnetized plasma sheath formation is the ion cyclotron time.
Influence of mass and potential energy surface geometry on roaming in Chesnavich’s CH4+ model
Authors: Krajňák Vladimír , Wiggins Stephen
Published: September 2018

Chesnavich’s model Hamiltonian for the reaction CH4+→ CH3+ + H is known to exhibit a range of interesting dynamical phenomena including roaming. The model system consists of two parts: a rigid, symmetric top representing the CH3+ ion and a free H atom. We study roaming in this model with focus on the evolution of geometrical features of the invariant manifolds in phase space that govern roaming under variations of the mass of the free atom m and a parameter a that couples radial and angular motion. In addition, we establish an upper bound on the prominence of roaming in Chesnavich’s model. The bound highlights the intricacy of roaming as a type of dynamics on the verge between isomerisation and nonreactivity as it relies on generous access to the potential wells to allow reactions as well as a prominent area of high potential that aids sufficient transfer of energy between the degrees of freedom to prevent isomerisation.
Regimes of magnetic reconnection in colliding laser-produced magnetized plasma bubbles
Authors: Lezhnin K. V. , Fox W. , Matteucci J. , Schaeffer D. B. , Bhattacharjee A. , Rosenberg M. J. , Germaschewski K.
Published: September 2018

We conduct a multiparametric study of driven magnetic reconnection relevant to recent experiments on colliding magnetized laser-produced plasmas using particle-in-cell simulations. Varying the background plasma density, plasma resistivity, and plasma bubble geometry, the 2D simulations demonstrate a rich variety of reconnection behaviors and show the coupling between magnetic reconnection and the global hydrodynamical evolution of the system. We consider both the collision between two radially expanding bubbles where reconnection is seeded by the pre-existing X-point and the collision between two flows in a quasi-1D geometry with initially anti-parallel fields where reconnection must be initiated by the tearing instability. At a baseline case of low-collisionality and low background density, the current sheet is strongly compressed to below scale of the ion-skin-depth scale, and rapid, multi-plasmoid reconnection results. Increasing the plasma resistivity, we observe a collisional slow-down of reconnection and stabilization of plasmoid instability for Lundquist numbers less than approximately S ∼ 103. Second, increasing the background plasma density modifies the compressibility of the plasma and can also slow down or even prevent reconnection, even in completely collisionless regimes, by preventing the current sheet from thinning down to the scale of the ion-skin depth. These results have implications for understanding recent and future experiments, and signatures for these processes for proton-radiography diagnostics of these experiments are discussed.
The C(3P) + NO(X2Π) → O(3P) + CN(X2Σ+), N(2D)/N(4S) + CO(X1Σ+) reaction: Rates, branching ratios, and final states from 15 K to 20 000 K
Authors: Koner Debasish , Bemish Raymond J. , Meuwly Markus
Published: September 2018

The C + NO collision system is of interest in the area of high-temperature combustion and atmospheric chemistry. In this work, full dimensional potential energy surfaces for the 2A′, 2A″, and 4A″ electronic states of the [CNO] system have been constructed following a reproducing kernel Hilbert space approach. For this purpose, more than 50 000 ab initio energies are calculated at the MRCI+Q/aug-cc-pVTZ level of theory. The dynamical simulations for the C(3P) + NO(X2Π) → O(3P) + CN(X2Σ+), N(2D)/N(4S) + CO(X1Σ+) reactive collisions are carried out on the newly generated surfaces using the quasiclassical trajectory (QCT) calculation method to obtain reaction probabilities, rate coefficients, and the distribution of product states. Preliminary quantum calculations are also carried out on the surfaces to obtain the reaction probabilities and compared with QCT results. The effect of nonadiabatic transitions on the dynamics for this title reaction is explored within the Landau-Zener framework. QCT simulations have been performed to simulate molecular beam experiment for the title reaction at 0.06 and 0.23 eV of relative collision energies. Results obtained from theoretical calculations are in good agreement with the available experimental as well as theoretical data reported in the literature. Finally, the reaction is studied at temperatures that are not practically achievable in the laboratory environment to provide insight into the reaction dynamics at temperatures relevant to hypersonic flight.
The sine process under the influence of a varying potential
Authors: Bothner Thomas , Deift Percy , Its Alexander , Krasovsky Igor
Published: September 2018

We review the authors’ recent work where we obtain the uniform large s asymptotics for the Fredholm determinant D(s,γ)≔det(I−γKs↾L2(−1,1)), 0 ≤ γ ≤ 1. The operator Ks acts with kernel Ks(x, y) = sin(s(x − y))/(π(x − y)), and D(s, γ) appears for instance in Dyson’s model of a Coulomb log-gas with varying external potential or in the bulk scaling analysis of the thinned Gaussian unitary ensemble.
Detailed analysis reveals differences between single-crystal and polycrystalline nickel features
Authors: Liebendorfer Adam
Published: September 2018

Characterizing the secondary electron emission behavior of Ni(110), a single-crystal form of nickel, demonstrates potential implications for plasma-enhanced chemistry.
Performance, meat quality and fatty acid profile of broiler chickens fed mixed semi-purified glycerin
Authors: Garcia E. R. M. , Murakami A. E. , Ospina-Rojas I. C. , Guerra A. F. Q. G.
Published: September 2018

The aim of the present study was to evaluate the effects of the inclusion of mixed (animal and vegetable sources) semi-purified glycerin (MSPG) in broiler diets on performance, litter moisture, serum glycerol concentration, carcass and parts yields, meat quality, and the fatty acid profile. In total, 576 1-day-old male Cobb 500 broiler chicks were distributed in a completely randomised design into four treatments (0%, 2.5%, 5.0% and 7.5% dietary inclusion levels of MSPG, as-fed basis), with six replicate pens of 24 birds each. The apparent metabolisable energy corrected for nitrogen balance and energy metabolisability coefficient values of the MSPG were 12.33 MJ/kg DM and 81.61% respectively. There was no significant (P > 0.05) effect of the MSPG concentration on the performance, and carcass and parts yields or broiler meat-quality variables, except for thigh meat colour, in which the yellowness value (b*) decreased linearly (P < 0.05) with an increasing inclusion level of MSPG. Litter moisture and serum glycerol increased linearly (P < 0.05) and the lipid profile of the thigh and drumstick meat of broilers at 42 days of age was slightly altered (P < 0.05) with an increasing MSPG. Mixed semi-purified glycerin can be used at up to 7.5% in broiler diets without impairing performance, meat quality, carcass and parts yields from 1 to 42 days of age. However, special attention should be paid to litter moisture.
Structural conditions on complex networks for the Michaelis–Menten input–output response
Authors: Wong Felix , Dutta Annwesha , Chowdhury Debashish , Gunawardena Jeremy
Published: September 2018

Significance

The Michaelis–Menten (MM) formula arose to explain simple enzyme behavior. It has since been found to describe input–output responses in several other biological contexts. Its ubiquity has been surprising and poorly understood. Here, we use the graph-based “linear framework” to show how the MM formula arises whenever appropriate structural conditions are satisfied, both at thermodynamic equilibrium and when energy is being dissipated. These conditions are based on separating the graph into two parts and constraining how and where the input variable appears. The conditions do not depend on parameter values and allow many of the details to be arbitrary. This explains the ubiquity of the MM formula and substantially generalizes previous results.
Mutually inhibitory Ras-PI(3,4)P
2
feedback loops mediate cell migration
Authors: Li Xiaoguang , Edwards Marc , Swaney Kristen F. , Singh Nilmani , Bhattacharya Sayak , Borleis Jane , Long Yu , Iglesias Pablo A. , Chen Jie , Devreotes Peter N.
Published: September 2018

Significance

Cell migration is central in physiological and pathological conditions such as immune response and cancer metastasis. The excitable network hypothesis can account for recent observations of propagating waves of signal transduction and cytoskeleton events as well as behaviors of migrating cells. However, the molecular feedback loops involved in these networks that bring about excitability are poorly understood. Here, we provide evidence for a positive-feedback loop based on a mutual inhibitory interaction between Ras and phosphatidylinositol (3,4)-bisphosphate [PI(3,4)P
2
]. Our results uncover an important role of PI(3,4)P
2
in the regulation of Ras activity, which may extend well beyond cell migration.
Collective shadows on the sociodrama stage
Authors: Ulon Siyat , Brooks Robin McCoy
Published: September 2018

Jung was not interested in exploring group dynamics within the many dimensions of concrete social reality that the authors claim also contributes to how we are formed as individuals in addition to psychical phenomena. Our interactions with these concrete and psychical phenomena have lingering effects on both the individual and the intersecting social worlds to which we are inured across the planet and through time. The authors argue that sociodrama facilitates the exploration of uncritically held ideological belief structures that are influenced by these interactions that can hinder our ability to bear responsibility for our transactions within any collective. The authors’ theoretical assumptions that support sociodramatic exploration within an academic conference environment are elaborated, including details about a diversity sociodramatic exploration the authors conducted during the International Association for Jungian Studies (IAJS) conference in Cape Town, South Africa in 2017. The article further includes a depiction and critique of this sociodramatic demonstration that occurred as an example of its applicability in conferences such as this one.
Intronless mRNAs transit through nuclear speckles to gain export competence
Authors: Wang Ke , Wang Lantian , Wang Jianshu , Chen Suli , Shi Min , Cheng Hong
Published: September 2018

Nuclear speckles (NSs) serve as splicing factor storage sites. In this study, we unexpectedly found that many endogenous intronless mRNAs, which do not undergo splicing, associate with NSs. These associations do not require transcription, polyadenylation, or the polyA tail. Rather, exonic splicing enhancers present in intronless mRNAs and their binding partners, SR proteins, promote intronless mRNA localization to NSs. Significantly, speckle targeting of mRNAs promotes the recruitment of the TREX export complex and their TREX-dependent nuclear export. Furthermore, TREX, which accumulates in NSs, is required for releasing intronless mRNAs from NSs, whereas NXF1, which is mainly detected at nuclear pores, is not. Upon NXF1 depletion, the TREX protein UAP56 loses speckle concentration but coaccumulates with intronless mRNAs and polyA RNAs in the nucleoplasm, and these RNAs are trapped in NSs upon UAP56 codepletion. We propose that the export-competent messenger RNP assembly mainly occurs in NSs for intronless mRNAs and that entering NSs serves as a quality control step in mRNA export.
Mechanical principles of nuclear shaping and positioning
Authors: Lele Tanmay P. , Dickinson Richard B. , Gundersen Gregg G.
Published: September 2018

Positioning and shaping the nucleus represents a mechanical challenge for the migrating cell because of its large size and resistance to deformation. Cells shape and position the nucleus by transmitting forces from the cytoskeleton onto the nuclear surface. This force transfer can occur through specialized linkages between the nuclear envelope and the cytoskeleton. In response, the nucleus can deform and/or it can move. Nuclear movement will occur when there is a net differential in mechanical force across the nucleus, while nuclear deformation will occur when mechanical forces overcome the mechanical resistance of the various structures that comprise the nucleus. In this perspective, we review current literature on the sources and magnitude of cellular forces exerted on the nucleus, the nuclear envelope proteins involved in transferring cellular forces, and the contribution of different nuclear structural components to the mechanical response of the nucleus to these forces.
Myoepithelial crowd control of cancer cells
Authors: Goodwin Katharine , Nelson Celeste M.
Published: September 2018

Smooth muscle–like cells can actively remodel epithelia, a mechanism common across developing tissues. In this issue, new work from Sirka et al. (2018. J. Cell Biol. https://doi.org/10.1083/jcb.201802144) demonstrates a novel mechanism for tumor suppression by smooth muscle–like myoepithelial cells of the mammary gland.
Preliminary assessment of the solar resource in the United Kingdom
Authors: Dhimish Mahmoud , Holmes Violeta , Mather Peter , Sibley Martin
Published: September 2018

Solar radiation resources data are the foundation of knowledge for programs of large-scale deployment of solar energy technologies. This article summarizes the analysis of a new weather stations network in the United Kingdom. The analysis used three years (January 2015–December 2017) of data from 27 weather stations distributed across the country. The data comprises global horizontal irradiance (GHI), diffuse horizontal irradiance, direct normal irradiance and the ambient temperature. Network design, implementation and data quality assurance are described to document the network extent and quality. From all observed datasets, we found that Plymouth (located in southwest England) has the dominant GHI and ambient temperature among all other 26 locations. The least GHI is observed for Aberdeen (located in northeast Scotland) estimated at 77.3 kWh/m2. The least average ambient temperature is equal to 9.1°C; the data were detected by the weather station located in the capital of Scotland (Edinburgh). Although continued measurements are needed to understand the interannual resource variability, the current study should have significant applications for preliminary technology selection, power plant modeling and resource forecasting.
A Predictive Visual Analytics Evaluation Approach Based on Adaptive Neuro-Fuzzy Inference System
Authors: Amri Saber , Ltifi Hela , Ben Ayed Mounir
Published: September 2018

The evaluation of visual analytics (VA) is a challenging field enabling analysts to get insight into diverse data types and formats. It aims at understanding events described by data and supporting the knowledge discovery process by integrating different data analysis methods. Recently, the evolution of intelligent decision support systems has enabled the inductive and predictive approaches of data analysis to make important decisions faster with a higher level of confidence and lower uncertainty. This paper introduces a new and intelligent evaluation method of VA that understands the users’ work as well as the features of their environments including vagueness, uncertainty and ambiguity due to workload. To this end, we apply an adaptive neuro-fuzzy inference system (ANFIS) to get quantitative and qualitative measures and determine the lowest evaluation score with better approximation. By combining fuzzy logic, used to deal with the inaccuracies and uncertainty problems during the evaluation process, and neural network, used to solve the problem of continuous changes in assessment environments with the delivery of adaptive learning content. By using the ANFIS approach that allows accurate prediction of evaluation scores, the proposed method seems more efficient compared to the recent evaluation methodology.
Adaptation strategies of coastal fishing communities as species shift poleward
Authors: Young Talia , Fuller Emma C , Provost Mikaela M , Coleman Kaycee E , St. Martin Kevin , McCay Bonnie J , Pinsky Malin L
Published: September 2018

In this period of environmental change, understanding how resource users respond to such changes is critical for effective resource management and adaptation planning. Extensive work has focused on natural resource responses to environmental changes, but less has examined the response of resource users to such changes. We used an interdisciplinary approach to analyse changes in resource use among commercial trawl fishing communities in the northwest Atlantic, a region that has shown poleward shifts in harvested fish species. We found substantial community-level changes in fishing patterns since 1996: southern trawl fleets of larger vessels with low catch diversity fished up to 400 km further north, while trawl fleets of smaller vessels with low catch diversity shrank or disappeared from the data set over time. In contrast, trawl fleets (of both large and small vessels) with higher catch diversity neither changed fishing location dramatically or nor disappeared as often from the data set. This analysis suggests that catch diversity and high mobility may buffer fishing communities from effects of environmental change. Particularly in times of rapid and uncertain change, constructing diverse portfolios and allowing for fleet mobility may represent effective adaptation strategies.
Do I Look and Sound Religious? Interviewer Religious Appearance and Attitude Effects on Respondents’ Answers
Authors: Mneimneh Zeina N , de Jong Julie , Cibelli Hibben Kristen , Moaddel Mansoor
Published: September 2018

Research has shown that interviewers can significantly affect survey respondents’ reported attitudes and behaviors. Several interviewer characteristics have been found to partially explain variation in respondents’ answers across interviewers, particularly when questions are related to interviewers’ observable characteristics such as gender, race, and age. However, less is known about if and how interviewers’ religious appearance and religious attitudes affect survey responses and, more specifically, reports about religious attitudes. Collecting accurate information on religious attitudes is important, given the sensitivity of this information across the globe and the growing interest in understanding religious perceptions and misconceptions. This paper is the first to investigate (a) the independent effects and the interplay between interviewers’ religious veil status and interviewers’ religious attitudes on respondents’ reported religious attitudes and (b) the magnitude of the interviewer variance explained by interviewers’ religious characteristics. The data comes from a nationally representative survey of religious and political attitudes in Tunisia carried out in 2013. Data from the survey also includes information about interviewers’ characteristics (including veil status for females) and interviewers’ own religious attitudes based on their responses to the same survey questions asked of respondents. Results showed that respondents interviewed by veiled female interviewers reported greater religiosity than respondents interviewed by unveiled female interviewers. Equally important were interviewers’ religious attitudes, which also independently affected the corresponding attitudes of respondents and explained a substantial percentage of the between-interviewer variance for several outcomes. The effect of interviewers’ attitudes on respondents’ attitudes was not stronger among veiled interviewers. Our investigation also revealed that the effect of interviewers’ attitudes on respondents’ reported attitudes operated somewhat differently for male and female respondents depending on the specific survey items. Future studies are needed to explore the mechanism(s) underlying these effects.