bluuebunny/crossref_metadata_2025 huggingface dataset:
Size effects on free vibration of heterogeneous beams
Authors: Hassanati Bahman , Wheel Marcus
Published: February 2018

In this paper the influence of microstructure on the free vibration of geometrically similar heterogeneous beams with free-free boundary conditions was numerically investigated by detailed finite element analysis (FEA) to identify and quantify any effect of beam size on transverse modal frequencies when the microstructural scale is comparable to the overall size. ANSYS Mechanical APDL was used to generate specific unit cells at the microstructural scale comprised of two isotropic materials with different material properties. Unit cell variants containing voids and inclusions were considered. At the macroscopic scale, four beam sizes consisting of one, two, three or four layers of defined unit cells were represented by repeatedly regenerating the unit cell as necessary. In all four beam sizes the aspect ratio was kept constant. Changes to the volume fractions of each material were introduced while keeping the homogenized properties of the beam fixed. The influence of the beam surface morphology on the results was also investigated. The ANSYS results were compared with the analytical results from solution to Timoshenko beam and nonlocal Timoshenko beam as well as numerical results for a Micropolar beam. In nonlocal Timoshenko beams the Eringen’s small length scale coefficients were estimated for some of the studied models. Numerical analyses based on Micropolar theory were carried out to study the modal frequencies and a method was suggested to estimate characteristic length in bending and coupling number via transverse vibration which verifies the use of Micropolar elasticity theory in dynamic analysis.
On displacement based non-local models for non-linear vibrations of thin nano plates
Authors: Chuaqui Tomás R. C. , Ribeiro Pedro
Published: February 2018

This paper addresses the formulation of displacement based, non-linear, plate models adopting Eringen's non-local elasticity, to study the modes of vibration of thin, nano plates. Plate models governed by ordinary differential equations of motion with generalized displacements as unknowns have some advantages over mixed type formulations, but difficulties arise in the development of such non-linear models when non-local effects are taken into account. To circumvent those difficulties, approximations of debatable justification can be imposed. Different approximations are discussed here and the accuracy of the best non-local, non-linear displacement based model achieved is put to test, by carrying out comparisons with a model based on Airy’s stress function.
Experimental studies of a single flexibly-mounted rod in a triangular rod bundle in cross-flow
Authors: Upnere Sabine , Jekabsons Normunds , Dementjevs Sergejs , Wohlmuther Michael
Published: February 2018

Experiments on flow-induced vibrations using a closely-packed triangular rod array with a pitch-todiameter ratio of 1.1 in water cross-flow was carried out at Paul Scherrer Institute. The bundle consists of 21 row of five rods in each one. Single flexibly-mounted test rod (TR) is in the fourth row in an otherwise fixed array. The test rod can freely move in the transverse and in-line direction. Two accelerometer sensors were attached at both ends of the TR to measure the rod response on the fluid flow. The effect of flow rate on the stability of the flexibly-mounted TR has been analysed. During experiments, it reveals a set of conditions and tendencies for the flow-induced vibration in the closely-packed multi-rod system.
Particular aspects regarding the effects of whole body vibration exposure
Authors: Picu Mihaela , Picu Laurentiu
Published: February 2018

This paper analyses the influence of whole-body vibrations on human performance; for this it was investigated how a group of men (20-29 years of age) and a group of woman (21–31 years of age) answered to specific requirements after being subjected to vertical vibrations under controlled laboratory conditions for 10-25 min. The vibrations were generated by a vibrant system with known amplitudes and frequencies. Accelerations were measured with NetdB - complex system for measuring and analysing human vibration and they were found in the range 0.4 - 3.1m/s2. The subjects’ performances were determined for each vibration level using specific tests. It can be concluded that exposure to vibrations higher than those recommended by ISO 2631 significantly disrupts how subjects responded to tests requirements.
State Switching of a Multistable Impacting System using PDLike Control
Authors: Liu Boying , Fung Wai-keung , Liu Yang
Published: February 2018

A new PD-like control law is proposed in this paper to control a multistable impacting system. This control law can switch the system from a current, undesired state to a desired one by using the differences of the displacement and velocity between the current and desired states. The control law can control the multistable system without affecting its original dynamics, and its stability is proved by using the Lyapunov direct method. Numerical results are compared with the results obtained by using the intermittent control studied in [1]. The proposed PD-like control shows a better performance in terms of the smoothness of its control signal, which is easier to be implemented in practical applications.
Real-Time Order Tracking of Gear Mesh Vibration in High Speed Planetary Gearboxes
Authors: Plöger Daniel Fritz , Zech Philipp , Rinderknecht Stephan
Published: February 2018

Possible approaches to real-time order tracking are discussed. Two methods for real-time order tracking are developed and validated experimentally for the entire audible spectrum. An adaptive heterodyne filter bank is compared to a direct integral transform. The performance of both methods is adequate for usage in an active vibration control (AVC) algorithm. Vold-Kalman filters are not suitable for AVC. The vibration data of three different planetary gearboxes is analyzed using order tracking. While some of the existing research could be reproduced, the data contradicts statements made by several authors. Lastly, the architecture of a novel AVC algorithm is sketched out.
Development of Approaches to Creation of Active Vibration Control System in Problems of the Dynamics for Granular Media
Authors: Khomenko Andrei P. , Kargapoltsev Sergey K. , Eliseev Andrey V.
Published: February 2018

The article deals with the development of mathematical models and evaluation criteria of the vibration field in the dynamic interactions of the elements of the vibrational technological machines for the processes of vibrational strengthening of long-length parts with help of a steel balls working medium. The study forms a theoretical understanding of the modes of motions of material particles in interaction with a vibrating surface of the working body of the vibration machine. The generalized approach to the assessment of the dynamic quality of the work of vibrating machines in multiple modes of tossing, when the period of free flight of particles is a multiple of the period of the surface oscillations of the working body, is developed in the article. For the correction of vibration field of the working body, the characteristics of dynamic interactions of granular elements of the medium are taken into account using original sensors. The sensors that can detect different particularities of interaction of the granular medium elements at different points of the working body are proposed to evaluate the deviation from a homogeneous and one-dimensional mode of vibration field. Specially developed sensors are able to register interactions between a single granule, a system of granules in filamentous structures, and multipoint interactions of the elements in a close-spaced cylindrical structure. The system of regularization of the structure of vibration fields based on the introduction of motion translation devices is proposed using the multi-point sensor locations on the working body. The article refers to analytical approaches of the theory of vibration displacements. For the experimental data assessment, the methods of statistical analysis are applied. It is shown that the peculiar features of the motion of granular medium registered by the sensors can be used to build active control systems of field vibration.
Broadband frequency response of a nonlinear resonator with clearance for energy harvesting
Authors: Łygas Krystian , Wolszczak Piotr , Litak Grzegorz
Published: February 2018

We examine the response of an inverted pendulum excited harmonically with amplitude limiters. Such a nonlinear resonator is suggested to work in the transduction of ambient vibration energy into the electrical power through bending of the moving beam. Using a multibody model we follow rotation and bending of the elastic beam and we provide the solutions of various frequencies. We found that the corresponding bending is the largest for subharmonic solutions of beam oscillations.
Nonlinear Vibrations of a Mechanism for the Miller-Atkinson Cycle
Authors: Dragomir Ionuţ , Mănescu Bogdan , Stănescu Nicolae–Doru
Published: February 2018

The distribution mechanism for the Miller-Atkinson is presented based on some previous papers of the authors. The cam is obtained in an analytical way and the optimization procedure of its shape based on Jarvis March algorithm is also described. The non-linear vibrations of the mechanism are analytically obtained used the Fourier transformation and they are numerically validated for different types of cams.
The effect of nylon nanofibers on the dynamic behaviour and the delamination resistance of GFRP composites
Authors: Garcia Cristobal , Trendafilova Irina , Zucchelli Andrea , Contreras Justin
Published: February 2018

Vibrations are responsible for a considerable number of accidents in aircrafts, bridges and other civil engineering structures. Therefore, there is a need to reduce the vibrations on structures made of composite materials. Delamination is a particularly dangerous failure mode for composite materials because delaminated composites can lose up to 60% of their strength and stiffness and still remain unchanged. One of the methods to suppress vibrations and preventing delamination is to incorporate nanofibers into the composite laminates. The aim of the present work is to investigate how nylon nanofibers affect the dynamic behaviour and delamination resistance of glass fibre reinforced polymer (GFRP) composites. Experiments and numerical simulations using finite element modelling (FEM) analysis are used to estimate the natural frequencies, the damping ratio and inter-laminar strength in GFRP composites with and without nylon nanofibers. It is found that the natural frequencies of the nylon nano-modified composites do not change significantly as compared to the traditional composites. However, nano-modified composites demonstrated a considerable increase in damping ratio and inter-laminar shear strength due to the incorporation of nylon nanofibers. This work contributes to the knowledge about the mechanical and dynamic properties of glass fibre reinforced polymer (GFRP) composites with nylon nanofibers.
Triboelectric nanogenerator as self-powered impact sensor
Authors: Garcia Cristobal , Trendafilova Irina , de Villoria Roberto Guzman , del Río Jose Sánchez
Published: February 2018

In recent years, triboelectric nanogenerators (TENGs) are used to harvest mechanical energy from ambient environment. These devices convert ambient energies (e.g. vibrations, breathing-driven, impacts or human body motions) into electricity based on the triboelectric effect. Furthermore, some TENGs can be successfully employed as self-power active sensors because the electric response from the TENG is proportional to the magnitude of the mechanical motion. This study report on the design and development of a novel triboelectric nanogenerator, and its potential application as self-powered impact sensor. To prepare the TENG device, membranes of polyvinylidene fluoride (PVDF) and polyvinylpyrrolidone (PVP) nanofibers are sandwiched between copper electrode films and wrapped on PET films. The TENG works based on the triboelectric interaction between the membranes of nanofibers. After the preparation, the TENGs are subjected to several impacts by the drop-ball impact test. The purpose of the experiment is to analyse if the electric response of TENG is dependent on the energy of the impact. The results of the experiment are presented and discussed. The main contributions of this work are the preparation of a novel nanogenerator (TENG) based on the triboelectric interaction between polyvinylidene fluoride and polyvinylpyrrolidone sub-micron polymer fibers and the investigation of its potential use as a self-powered impact sensor.
Vibration Based Damage Detection of Rotating Beams
Authors: Stoykov Stanislav , Manoach Emil , Cao Maosen
Published: February 2018

The early detection and localization of damages is essential for operation, maintenance and cost of the structures. Because the frequency of vibration cannot be controlled in real-life structures, the methods for damage detection should work for wide range of frequencies. In the current work, the equation of motion of rotating beam is derived and presented and the damage is modelled by reduced thickness. Vibration based methods which use Poincaré maps are implemented for damage localization. It is shown that for clamped-free boundary conditions these methods are not always reliable and their success depends on the excitation frequency. The shapes of vibration of damaged and undamaged beams are shown and it is concluded that appropriate selection criteria should be defined for successful detection and localization of damages.
Small-Scale Drilling Test Rig For Investigation of Axial Excitation On The Drilling Process
Authors: Austefjord A. , Blaylock S. , Forster I. , Sheehan M. , Wright C.
Published: February 2018

This paper describes the design, construction and operation of a small-scale drilling rig for the purpose of investigation of the effect of axial excitation on the drilling process. The rig is bench top in size and has been designed to drill small rock samples, whilst at the same allowing axial excitation to be induced into the drilling process. The rig has been designed to drill the rock without any drilling fluids – so allowing improved observation of the chip generation process. Additionally, the drilling weight on bit is applied via masses, so allowing greater representation of the dynamic behavior of the drilling process – i.e. capturing more natural frequencies. The results from the rig have been obtained over two frequency ranges – low frequency (0-50 Hz) and high frequency (50-250 Hz). Results show that improved rate of penetration is obtained with axial excitation – with low and high frequency optima occurring. These optima can be related to the behavior of the string in the two frequency ranges – in the low frequency range, the entire string acts in unison; whereas at high frequency, only the bit/rock system is active. As a result, it is concluded that for low frequency operation, only information about the drill string is required to optimize performance; whereas for high frequency operation, information about the bit/rock system is required to optimize performance. Observation of the chip generation process via high speed video has shown that during axial excitation, regular shaped bricks are ejected when compared with the typical wedge- shaped chips that are normally ejected during the drilling process. It is concluded that, during the axial excitation process, the chips are being ejected via a levering action, so allowing a more efficient and quicker process. MIT [1] provided background classes, project guidance and project review as part of an NOV/MIT advanced technology program. Larger scale lab tests and/or field tests are required to verify/validate these conclusions.
Die Rechtsfrage: An wen muss ich die Rechnung adressieren, wenn der Patient ein Kind ist?
Authors: Bossow Karsten
Published: February 2018

„Ich habe ein Therapiekind behandelt und die Rechnung auf das Kind ausgestellt. Nun weigert sich der – privat versicherte – Vater, die Rechnung zu bezahlen, weil er sich nicht angesprochen fühlt. Habe ich einen Fehler gemacht? An wen adressiere ich jetzt die Mahnung?“

Therapeutin aus Baden-Württemberg
Therapieprozess bei unbekanntem Krankheitsbild – Schritt für Schritt
Authors: Godau Kevin , Lang Rebecca , Wleklinski Svenja , Schug Corinna
Published: February 2018

In der Ergotherapie haben wir den Anspruch, professionell, klientenzentriert und evidenzbasiert vorzugehen. Auch bei Klienten mit einem uns unbekannten Krankheitsbild. Um das zu gewährleisten, durchlaufen wir den Clinical-Reasoning-Prozess von der Anmeldung des Klienten bis zu seiner Verabschiedung. Ein Erfahrungsbericht von Studierenden.
Slums, race and mental health in New York (1938–1965)
Authors: Doyle Dennis
Published: February 2018

Abstract

Claude Brown’s seminal 1965 memoir “Manchild in the Promised Land” appeared when Americans were trying to make sense of the Watts Rebellion of 1965. A “bildungsroman”, Brown’s autobiography details how he, a former juvenile delinquent and residential treatment center client, became a stable adult once he left his troubled Harlem neighborhood. This paper argues that Brown’s book revealed just how much liberal mid-twentieth century efforts to combat poverty and crime in segregated black communities by offering more mental health services struggled to fully grasp and address the relationship between mental health and environment. Between 1938 and 1965, officials and mental health experts with the Wiltwyck School for Boys, New York Domestic Relations Court and the New York Bureau of Child Guidance imagined that Harlem would become a more stable, law-abiding community if populated with emotionally healthier people. Methodologically, this paper compares the archival record of those programs’ goals with Brown’s memoir. Brown’s own experience as both a former charge of those institutions and a resident of Harlem led him to doubt that urban ghettoes were environmentally suited to support individuals struggling to overcome mental illness. In locating Brown’s recollection of his postwar youth within the context of local efforts to provide New York City’s black juvenile delinquents with psychiatric care in the postwar era, it becomes apparent that those liberal policies and programs were designed to produce therapeutic outcomes that proved difficult to sustain amid the challenging circumstances residents faced in socioeconomically depressed communities. As an intervention into the burgeoning literature on the US history of race and psychiatry, this research represents one of the first attempts to compare the intentions of mental health professionals seeking to improve the health care of African Americans and the perspectives of their African American clients.
Gallium diffusion in zinc oxide via the paired dopant-vacancy mechanism
Authors: Sky T. N. , Johansen K. M. , Riise H. N. , Svensson B. G. , Vines L.
Published: February 2018

Isochronal and isothermal diffusion experiments of gallium (Ga) in zinc oxide (ZnO) have been performed in the temperature range of 900–1050 °C. The samples used consisted of a sputter-deposited and highly Ga-doped ZnO film at the surface of a single-crystal bulk material. We use a novel reaction diffusion (RD) approach to demonstrate that the diffusion behavior of Ga in ZnO is consistent with zinc vacancy (VZn) mediation via the formation and dissociation of GaZnVZn complexes. In the RD modeling, experimental diffusion data are fitted utilizing recent density-functional-theory estimates of the VZn formation energy and the binding energy of GaZnVZn. From the RD modeling, a migration energy of 2.3 eV is deduced for GaZnVZn, and a total/effective activation energy of 3.0 eV is obtained for the Ga diffusion. Furthermore, and for comparison, employing the so-called Fair model, a total/effective activation energy of 2.7 eV is obtained for the Ga diffusion, reasonably close to the total value extracted from the RD-modeling.
Single crystal to polycrystal neutron transmission simulation
Authors: Dessieux L. L. , Stoica A. D. , Bingham P. R.
Published: February 2018

A collection of routines for calculation of the total cross section that determines the attenuation of neutrons by crystalline solids is presented. The total cross section is calculated semi-empirically as a function of crystal structure, neutron energy, temperature, and crystal orientation. The semi-empirical formula includes the contribution of parasitic Bragg scattering to the total cross section using both the crystal’s mosaic spread value and its orientation with respect to the neutron beam direction as parameters. These routines allow users to enter a distribution of crystal orientations for calculation of total cross sections of user defined powder or pseudo powder distributions, which enables simulation of non-uniformities such as texture and strain. The spectra for neutron transmission simulations in the neutron thermal energy range (2 meV–100 meV) are presented for single crystal and polycrystal samples and compared to measurements.
Engineered Gd-Co based multilayer stack to enhanced magneto-caloric effect and relative cooling power
Authors: Tadout M. , Lambert C.-H. , El Hadri M. S. , Mounkachi O. , Benyoussef A. , Hamedoun M. , Benaissa M. , Mangin S.
Published: February 2018

Magnetic refrigeration based on the magneto-caloric effect is one of the best alternatives to compete with vapor-compression technology. The viability of a magnetic refrigeration system for magnetic cooling can be tested by exploiting the materials in various forms, ranging from bulk to nanostructured materials. In order to achieve a wide refrigerating temperature range in magnetic refrigeration, we study in this paper a 100 nm-thick Gd-Co alloys-based multilayer stack. The stack is made of four individual Gd-Co alloy layers with different values of concentration and Curie temperature (TC). A magnetic entropy change associated with the second-order magnetic phase transition was determined from the magnetic isotherms. Moreover, the relative cooling power (RCP) of the studied Gd-Co-based multilayer is enhanced compared to the one of bulk Gd, and reaches a value of 200 J/kg. Such an enhancement of the RCP is not due to an enhanced maximum variation of entropy, but this is due to a much broader magnetic entropy peak. This study demonstrates the potential of nanostructured Gd-Co multilayer stack for magnetic cooling applications.
Quantum diffusion of H/D on Ni(111)—A partially adiabatic centroid MD study
Authors: Hopkinson A. R. , Probert M. I. J.
Published: February 2018

We present the results of a theoretical study of H/D diffusion on a Ni(111) surface at a range of temperatures, from 250 K to 75 K. The diffusion is studied using both classical molecular dynamics and the partially adiabatic centroid molecular dynamics method. The calculations are performed with the hydrogen (or deuterium) moving in 3D across a static nickel surface using a novel Fourier interpolated potential energy surface which has been parameterized to density functional theory calculations. The results of the classical simulations are that the calculated diffusion coefficients are far too small and with too large a variation with temperature compared with experiment. By contrast, the quantum simulations are in much better agreement with experiment and show that quantum effects in the diffusion of hydrogen are significant at all temperatures studied. There is also a crossover to a quantum-dominated diffusive regime for temperatures below ∼150 K for hydrogen and ∼85 K for deuterium. The quantum diffusion coefficients are found to accurately reproduce the spread in values with temperature, but with an absolute value that is a little high compared with experiment.
Blowup criterion and persistent decay for a modified Camassa-Holm system
Authors: Wei L. , Wang Y.
Published: February 2018

In this paper, we study a modified two-component Camassa-Holm system modeling shallow water waves moving over a linear shear flow. We demonstrate a condition on the initial data that lead to finite time blow-up of solutions. By moderate weight functions from time-frequency analysis, we provide persistence results for solutions of the system in weighted Lp-spaces for a large class of moderate weights.
Renner-Teller effects in the photoelectron spectra of CNC, CCN, and HCCN
Authors: Coudert Laurent H. , Gans Bérenger , Garcia Gustavo A. , Loison Jean-Christophe
Published: February 2018

The line intensity of photoelectron spectra when either the neutral or cationic species display a Renner-Teller coupling is derived and applied to the modeling of the photoelectron spectra of CNC, CCN, and HCCN. The rovibronic energy levels of these three radicals and of their cations are investigated starting from ab initio results. A model treating simultaneously the bending mode and the overall rotation is developed to deal with the quasilinearity problem in CNC+, CCN+, and HCCN and accounts for the large amplitude nature of their bending mode. This model is extended to treat the Renner-Teller coupling in CNC, CCN, and HCCN+. Based on the derived photoelectron line intensity, the photoelectron spectra of all three molecules are calculated and compared to the experimental ones.
Soret forced Rayleigh scattering instrument for simultaneous detection of two-wavelength signals to measure Soret coefficient and thermodiffusion coefficient in ternary mixtures
Authors: Matsuura H. , Nagasaka Y.
Published: February 2018

We describe an instrument for the measurement of the Soret and thermodiffusion coefficients in ternary systems based on the transient holographic grating technique, which is called Soret forced Rayleigh scattering (SFRS) or thermal diffusion forced Rayleigh scattering (TDFRS). We integrated the SFRS technique and the two-wavelength detection technique, which enabled us to obtain two different signals to determine the two independent Soret coefficients and thermodiffusion coefficients in ternary systems. The instrument has been designed to read the mass transport simultaneously by two-wavelength lasers with wavelengths of λ = 403 nm and λ = 639 nm. The irradiation time of the probing lasers is controlled to reduce the effect of laser absorption to the sample with dye (quinizarin), which is added to convert the interference pattern of the heating laser of λ = 532 nm to the temperature grating. The result of the measurement of binary benchmark mixtures composed of 1,2,3,4-tetrahydronaphthalene (THN), isobutylbenzene (IBB), and n-dodecane (nC12) shows that the simultaneous two-wavelength observation of the Soret effect and the mass diffusion are adequately performed. To evaluate performance in the measurement of ternary systems, we carried out experiments on the ternary benchmark mixtures of THN/IBB/nC12 with the mass fractions of 0.800/0.100/0.100 at a temperature of 298.2 K. The Soret coefficient and thermodiffusion coefficient agreed with the ternary benchmark values within the range of the standard uncertainties (23% for the Soret coefficient of THN and 30% for the thermodiffusion coefficient of THN).
FDTD simulation of radar cross section reduction by a collisional inhomogeneous magnetized plasma
Authors: Foroutan V. , Azarmanesh M. N. , Foroutan G.
Published: February 2018

The recursive convolution finite difference time domain method is addressed in the scattered field formulation and employed to investigate the bistatic radar cross-section (RCS) of a square conductive plate covered by a collisional inhomogeneous magnetized plasma. The RCS is calculated for two different configurations of the magnetic field, i.e., parallel and perpendicular to the plate. The results of numerical simulations show that, for a perpendicularly applied magnetic field, the backscattered RCS is significantly reduced when the magnetic field intensity coincides with the value corresponding to the electron cyclotron resonance. By increasing the collision frequency, the resonant absorption is suppressed, but due to enhanced wave penetration and bending, the reduction in the bistatic RCS is improved. At very high collision frequencies, the external magnetic field has no significant impact on the bistatic RCS reduction. Application of a parallel magnetic field has an adverse effect near the electron cyclotron resonance and results in a large and asymmetric RCS profile. But, the problem is resolved by increasing the magnetic field and/or the collision frequency. By choosing proper values of the collision frequency and the magnetic field intensity, a perpendicular magnetic field can be effectively used to reduce the bistatic RCS of a conductive plate.
Optimized lighting method of applying shaped-function signal for increasing the dynamic range of LED-multispectral imaging system
Authors: Yang Xue , Hu Yajia , Li Gang , Lin Ling
Published: February 2018

This paper proposes an optimized lighting method of applying a shaped-function signal for increasing the dynamic range of light emitting diode (LED)-multispectral imaging system. The optimized lighting method is based on the linear response zone of the analog-to-digital conversion (ADC) and the spectral response of the camera. The auxiliary light at a higher sensitivity-camera area is introduced to increase the A/D quantization levels that are within the linear response zone of ADC and improve the signal-to-noise ratio. The active light is modulated by the shaped-function signal to improve the gray-scale resolution of the image. And the auxiliary light is modulated by the constant intensity signal, which is easy to acquire the images under the active light irradiation. The least square method is employed to precisely extract the desired images. One wavelength in multispectral imaging based on LED illumination was taken as an example. It has been proven by experiments that the gray-scale resolution and the accuracy of information of the images acquired by the proposed method were both significantly improved. The optimum method opens up avenues for the hyperspectral imaging of biological tissue.
Rehearsing the crisis
Authors: Coleman Stephen
Published: February 2018

This chapter considers the 2008 global financial crisis as an example of how crises are imagined and scripted as political projects before they are mediated as a social reality. It argues that the articulation of this reality was discursively constructed and selectively mediated and that it is impossible to think about how crises are imagined and debated without thinking about the discursive constraints that frame their construction.
The visual construction of political crises
Authors: Lorenzo-Dus Nuria , Smith Philippa
Published: February 2018

This chapter examines the visual construction of social actors (elite and non-elite) in all the news stories about political crises published by the British broadsheet The Independent between 2008 and 2014. Our findings show that the practices involved in the construction of political crises are overwhelmingly linked to oral communication. Yet the kind of oral communication through which political crises are visually rendered varies significantly according to the (non)elite status of the groups being visually framed. Whereas elite groups are visually constructed as dealing with political crises through measured, rational talk, non-elite groups are visually represented as either handling political crises in aggressive ways or as being their hopeless recipients. Our findings also support the thesis that the concept of crisis has undergone a process of ‘semantic inflation’ in postmodernity.
Impending crisis in Scotland
Authors: Higgins Michael
Published: February 2018

This chapter looks at the management of political instability across the political and media spheres before and after the 2014 Scottish independence referendum, and prior to the UK’s vote to exit the European Union. Looking first at a selection of political speeches, the chapter finds those politicians opposed to independence construct constitutional change as impending crisis, whereas speeches from a pro-independence position articulate the pursuit of a new political settlement as a means of crisis aversion at an EU and international level. In turning the analysis to a media context, the Scottish newspapers, all of which were opposed to independence, emphasise the threat of upheaval, and extend the crisis frame onto coverage of the economy and the National Health Service. Overall, while explicit references to crisis are comparatively unusual amongst politicians and across media, the chapter suggests the tactical use of a “crisis” frame is an important component of political discourse in times of constitutional uncertainty.
Fabrication of a robust superhydrophobic polyurethane sponge for oil–water separation
Authors: Cheng Qianhui , Liu Changsong , Liu Shengyou
Published: February 2018

In this study, a robust superhydrophobic ZnO microparticle coating was applied to the surface of a polyurethane sponge through a simple solvothermal and chemical vapour deposition method. The thickly hierarchical ZnO microparticle and the long chain alkyl of hexadecyltrimethoxysilane make the sponge exhibit excellent superhydrophobicity and superoleophilicity. By combining excellent superwetting characteristics and a larger surface area, the resulting sponges exhibited high oil-absorption capacity and selectivity for oil–water separation. The durability of the sponge was investigated by two methods, one is ultrasonication in acetone and hexane, the other is anti-resistance in acid and alkali solution. Reusability was tested by repeated absorption–desorption processes. Owing to the good adhesion between the coating and the sponge, the as-prepared sponge shows high durability and reusability. Moreover, the sponge can degrade toxic methylene blue under ultraviolet light irradiation. Therefore, this paper offers a simple and low-cost strategy for the fabrication of absorption materials.
Surface mechanical coating of Cu plate by Cu Al powders
Authors: Farahbakhsh Iman , Mashimo Tsutomu
Published: February 2018

Through Surface Mechanical Coating (SMC), a plate of pure Cu was successfully coated using of Al-50-wt% Cu during mechanical alloying. Effect of milling time and heat treatment on formation of coating at 1050 °C was investigated. Compositional and microstructural study of the coating and its properties were conducted by means of X-Ray Diffraction (XRD), Micro-focus XRD, Scanning Electron Microscopic (SEM), Electron Probe Micro-Analyzer (EPMA), Transition Electron Microscopic (TEM), and Vickers Microhardness test. Analyses results showed that Al4Cu9, Cu(Al), and AlCu3 phases were formed. The results also showed that heating causes the composite coating created by SMC to be replaced with moderate concentrations of Cu and Al. Through heat treatment, coating hardness will be reduced to even half, while thickness has a twofold increase. As milling time rises, atomic diffusion depth for heated samples will be raised also. TEM investigations approved the presence of amorphous phase and 10nm grain size.
Same but different: pleiotropy in centrosome-related microcephaly
Authors: O’Neill Ryan S. , Schoborg Todd A. , Rusan Nasser M.
Published: February 2018

An intimate link between centrosome function and neurogenesis is revealed by the identification of many genes with centrosome-associated functions that are mutated in microcephaly disorders. Consistent with the major role of the centrosome in mitosis, mutations in these centrosome-related microcephaly (CRM) genes are thought to affect neurogenesis by depleting the pool of neural progenitor cells, primarily through apoptosis as a consequence of mitotic failure or premature differentiation as a consequence of cell cycle delay and randomization of spindle orientation. However, as suggested by the wide range of microcephaly phenotypes and the multifunctional nature of many CRM proteins, this picture of CRM gene function is incomplete. Here, we explore several examples of CRM genes pointing to additional functions that contribute to microcephaly, including regulation of cell cycle signaling, actin cytoskeleton, and Hippo pathway proteins, as well as functions in postmitotic neurons and glia. As these examples are likely just the tip of the iceberg, further exploration of the roles of microcephaly-related genes are certain to reveal additional unforeseen functions important for neurodevelopment.
Chinese and British Diplomatic Gifts in the Macartney Embassy of 1793
Authors: Harrison Henrietta
Published: February 2018

This paper looks at the choice, reception and afterlife of both the Chinese and the British gifts given during Britain’s first embassy to China. Earlier studies have tended to fault the Qing court for understanding the gifts they received as tribute and failing to appreciate the scientific items given by the British. However, gift-giving was a highly charged political issue in the domestic politics of both countries at this time and the terms in which the argument was conducted differed widely. This paper argues that the Chinese term that has been translated into the English ‘tribute’ did not have the same resonance in China, and that instead the gifts were received by both sides as part of the negotiations that accompanied the embassy. The most successful gifts in this context were those with an accepted monetary value in the existing trade between the two countries, notably high-quality textiles. British military gifts were also of importance in shaping the outcome of the embassy. However, attempts to use the gifts to present the culture or wider philosophical outlook of the giver were much less successful in this diplomatic context. After the embassy ended the vast majority of gifts given by both sides became exotic items in royal collections where they added to the glory of the recipient rather than that of the donor.
Reconstruction of Lorentzian Manifolds from Boundary Light Observation Sets
Authors: Hintz Peter , Uhlmann Gunther
Published: February 2018

On a time-oriented Lorentzian manifold (M, g) with nonempty boundary satisfying a convexity assumption, we show that the topological, differentiable, and conformal structure of suitable subsets S ⊂ M of sources is uniquely determined by measurements of the intersection of future light cones from points in S with a fixed open subset of the boundary of M; here, light rays are reflected at ∂M according to Snell’s law. Our proof is constructive, and allows for interior conjugate points as well as multiply reflected and self-intersecting light cones.
Moduli Spaces of Representations of Special Biserial Algebras
Authors: Carroll Andrew T , Chindris Calin , Kinser Ryan , Weyman Jerzy
Published: February 2018

We show that the irreducible components of any moduli space of semistable representations of a special biserial algebra are always isomorphic to products of projective spaces of various dimensions. This is done by showing that irreducible components of varieties of representations of special biserial algebras are isomorphic to irreducible components of products of varieties of circular complexes and therefore normal, allowing us to apply recent results of the second and third authors on moduli spaces.
Clinical Surveillance and Evaluation of Suspected Ebola Cases in a Vaccine Trial During an Ebola Epidemic: The Sierra Leone Trial to Introduce a Vaccine Against Ebola
Authors: Conteh Muhammad-Abbas , Goldstein Susan T , Wurie Haja R , Gidudu Jane , Lisk Durodami Radcliffe , Carter Rosalind J , Seward Jane F , Hampton Lee M , Wang David , Andersen Lauren E , Arvay Melissa , Schrag Stephanie J , Dawson Peter , Fombah Augustin E , Petrie Carey R , Feikin Daniel R , Russell James B W , Lindblad Robert , Kargbo S A S , Samai Mohamed , Mahon Barbara E
Published: February 2018

The Sierra Leone Trial to Introduce a Vaccine Against Ebola (STRIVE), an Ebola vaccine trial conducted during the 2014–2016 Ebola epidemic, coordinated with the Sierra Leone national response to identify Ebola cases among trial participants. The early symptoms of Ebola are similar to common vaccine reactions, so it was important to differentiate these to avoid unnecessary referral to an Ebola facility and an increased risk of Ebola exposure. STRIVE developed a modified version of the national case definition and case management algorithm to distinguish between symptoms associated with both Ebola and vaccination with the candidate Ebola vaccine (rVSV∆G-ZEBOV-GP) from those typically associated only with Ebola. For participants who presented ≤48 hours after vaccination, we used the more stringent modified case definition to trigger referral for Ebola evaluation. Participants whose symptoms did not meet case definitions could also be referred to an Ebola facility, based on clinical judgment. No Ebola cases were diagnosed among the 8651 STRIVE participants. Fifty participants were evaluated for Ebola, of whom 34 (68%) were tested after vaccination; 22 deceased participants, all of whom underwent postmortem Ebola testing, as required during the Ebola epidemic, and had negative test results, were excluded from analysis. Seven of 34 participants (21%) had symptom onset ≤48 hours after vaccination, of whom 3 met the modified case definition. The most common diagnosis among those evaluated for Ebola was malaria. STRIVE demonstrates the feasibility of conducting Ebola surveillance among persons vaccinated with rVSV-ZEBOV during an Ebola epidemic and introduces a modified case definition and case management algorithm to distinguish vaccine reactions from early symptoms of Ebola that may be useful for reducing unnecessary Ebola evaluations among persons vaccinated during Ebola outbreaks.

Clinical Trials Registration

ClinicalTrials.gov [NCT02378753] and Pan African Clinical Trials Registry [PACTR201502001037220].
Probiotic treatment during neonatal age provides optimal protection against experimental asthma through the modulation of microbiota and T cells
Authors: Nunes Caroline Fraga , Nogueira Jeane S , Vianna Pedro Henrique Oliveira , Ciambarella Bianca Torres , Rodrigues Patrícia Machado , Miranda Karla Rodrigues , Lobo Leandro Araújo , Domingues Regina Maria Cavalcanti Pillotto , Busch Mileane , Atella Georgia Correa , Vale André Macedo , Bellio Maria , Nóbrega Alberto , Canto Fábio B , Fucs Rita
Published: February 2018

The incidence of allergic diseases, which increased to epidemic proportions in developed countries over the last few decades, has been correlated with altered gut microbiota colonization. Although probiotics may play a critical role in the restoration of gut homeostasis, their efficiency in the control of allergy is controversial. Here, we aimed to investigate the effects of probiotic treatment initiated at neonatal or adult ages on the suppression of experimental ovalbumin (OVA)-induced asthma. Neonatal or adult mice were orally treated with probiotic bacteria and subjected to OVA-induced allergy. Asthma-like symptoms, microbiota composition and frequencies of the total CD4+ T lymphocytes and CD4+Foxp3+ regulatory T (Treg) cells were evaluated in both groups. Probiotic administration to neonates, but not to adults, was necessary and sufficient for the absolute prevention of experimental allergen-induced sensitization. The neonatally acquired tolerance, transferrable to probiotic-untreated adult recipients by splenic cells from tolerant donors, was associated with modulation of gut bacterial composition, augmented levels of cecum butyrate and selective accumulation of Treg cells in the airways. Our findings reveal that a cross-talk between a healthy microbiota and qualitative features inherent to neonatal T cells, especially in the Treg cell subset, might support the beneficial effect of perinatal exposure to probiotic bacteria on the development of long-term tolerance to allergens.
CD28 co-stimulation is dispensable for the steady state homeostasis of intestinal regulatory T cells
Authors: Wakamatsu Ei , Omori Hiroki , Tabata Yuki , Akieda Yuki , Watanabe Shiho , Ogawa Shuhei , Abe Ryo
Published: February 2018

It is well-established that CD28 co-stimulation is required for the development and the proliferation of thymus-derived regulatory T cells (tTregs). Meanwhile, the role of CD28 co-stimulation in the homeostasis of peripherally derived Tregs (pTregs) remains unclear. To clarify this issue, we analyzed Tregs in small and large intestines (SI and LI), the principle sites of pTreg development. Interestingly, and different from in the thymus, Tregs were abundant in the intestines of CD28−/− mice, and most of them were phenotypically pTregs. We showed that CD28−/− naive T cells differentiated into pTregs in the LI after oral exposure to antigens and that CD28−/− pTregs in the LI had the same highly proliferative activity as CD28+/− cells. CD28−/− pTregs acquired these Treg-specific features at transcriptional and epigenetics levels. On the other hand, some immune suppressive molecules were down-regulated in CD28−/− pTregs. Correspondingly, the suppressive activity of CD28−/− pTregs was weaker than CD28+/+ cells. These results indicate that the homeostasis of pTregs in the intestines is maintained even in the absence of CD28, whereas CD28 is required for the maximal suppressive activity of intestinal pTregs.
Neck Remnants and the Risk of Aneurysm Rupture After Endovascular Treatment With Coiling or Stent-Assisted Coiling: Much Ado About Nothing?
Authors: Munich Stephan A , Cress Marshall C , Rangel-Castilla Leonardo , Sonig Ashish , Ogilvy Christopher S , Lanzino Giuseppe , Petr Ondra , Mocco J , Morone Peter J , Snyder Kenneth V , Hopkins L Nelson , Siddiqui Adnan H , Levy Elad I
Published: February 2018

BACKGROUND

Neck remnants are not uncommon after endovascular treatment of cerebral aneurysms. Critics of endovascular treatments for cerebral aneurysms cite neck remnants as evidence in favor of microsurgical clipping. However, studies have failed to evaluate the true clinical significance of aneurysm neck remnants following endovascular therapies.

OBJECTIVE

To assess the clinical significance of residual aneurysm necks and to determine the rate of subsequent rupture following coiling or stent-assisted coiling of cerebral aneurysms.

METHODS

We retrospectively reviewed the records of 1292 aneurysm cases that underwent endovascular treatment at 4 institutions. Aneurysms treated by primary coiling or stent-assisted coiling were included in the study; those treated by flow diversion were excluded Aneurysms with residual filling (i.e., Raymond–Roy Occlusion Classification II, neck remnant; or III, residual aneurysm filling) were assessed for their risk of subsequent rupture.

RESULTS

A total of 626 aneurysms were identified as having residual filling immediately posttreatment. Of these, 13 aneurysms (2.1%) ruptured during the follow-up period (mean 7.3 mo; range 1-84 mo). Eleven of the 13 (84.6%) were ruptured at presentation. Rupture at presentation, the size of the aneurysm, and the increasing age of the patient were predictive of posttreatment rupture.

CONCLUSION

We found that unruptured aneurysms with residual necks following endovascular treatment posed a very low risk of rupture (0.6%). However, patients presenting with ruptured aneurysms had a higher risk of rerupture from a neck remnant (3.4%). These results highlight the importance of achieving complete angiographic occlusion of ruptured aneurysms.