bluuebunny/crossref_metadata_2025 huggingface dataset:
Laboratory implementation of electromagnetic torque based MRAS speed estimator for sensorless SMPMSM drive
Authors: Prabhakaran K.K. , Karthikeyan A. , Blaabjerg F.
Published: August 2019

This Letter proposes a simple electromagnetic torque based model reference adaptive system (MRAS) speed estimator for sensorless surface mount permanent magnet synchronous motor (SMPMSM) drive. The proposed estimator is formed using instantaneous measured and estimated electromagnetic torque. The proposed estimator is implemented for 1.5 kW laboratory prototype SMPMSM drive using field programmable gate array ALTERA cyclone II. Experimental results demonstrate the efficacy of the proposed scheme under different test conditions viz. different low‐speed regions and standstill at different load conditions with uncertainty in machine parameters. Results show that the estimator is stable in low‐speed regions and exhibits robustness against uncertainties in machine parameters.
Low complexity closed‐form covariance matrix and direct constant‐envelope waveforms design for MIMO radar transmit beampattern
Authors: Yu Wenqi , Cui Bingyu
Published: August 2019

Multiple‐input multiple‐output (MIMO) radar has many advantages over the phased‐array radar due to the waveform diversity, one of which is the greater flexibility to design the transmit beampattern. In this Letter, a low‐complexity transmit beampattern design method, considering constant envelope (CE) waveforms, is proposed for the uniform linear array MIMO radar. First, the authors parameterise the waveform covariance matrix as the integral form of continuous spatial variable, by exploiting the beamforming weight vector in the main lobe region, to derive the closed‐form solution of the waveform covariance matrix that fulfils positive semi‐definiteness and uniform elemental power constraints. The transmit beampattern designed by the proposed method has the spatial characteristics of low main lobe fluctuation and peak‐to‐sidelobe level, and further mathematical explanation is illuminated. Next, they directly use the parameterised expression of waveform covariance matrix, approximately transformed into a discrete form of the spatial variable based on the Riemann integral definition, to efficiently synthesise correlated CE waveforms. The proposed method can provide transmit beampattern performance comparable to existing methods with a lower computational cost and ensure the CE property of the waveforms. The performance of the proposed method is verified and analysed via numerical examples.
Holomorphic embedding load flow for unbalanced radial distribution networks with DFIG and tap‐changer modelling
Authors: Keihan Asl Dariush , Mohammadi Mohammad , Reza Seifi Ali
Published: August 2019

In this study, the holomorphic‐embedding method as a linear and non‐iterative method is developed and implemented to solve the load flow of the three‐phase unbalanced radial distribution networks. Previously, this method was used to solve the load flow problem of balanced transmission networks. The proposed methodology could be applied for a variety of unbalanced radial distribution networks with any number of buses and branches. The characteristics of unbalanced radial distribution networks including line coupling effects, unbalanced loads and unsymmetrical phases are considered in this study. The proposed method uses an unbalanced network structure and modifies the calculation approach of the admittance matrix. In this manner, an unbalanced network is modelled the same as the balanced networks. The tap‐changer, doubly‐fed induction generator (DFIG), and photovoltaic system are modelled in the admittance matrix or current injection vector. The performance of the proposed method is validated on the 19‐bus unbalanced radial distribution network. Finally, the effectiveness of the proposed method in solving the load flow problem is investigated.
Single sample description based on Gabor fusion
Authors: Chen Ting , Gao Tao , Zhao Xiangmo
Published: August 2019

Owing to lack of enough face image and invalidation of many traditional face recognition algorithms, face recognition with single training sample is really a great challenge. To solve the above problem, this study proposes a novel local weighted fusion Gabor (LWFG) algorithm. First, one single sample is segmented into a series of block sub‐images, and then, each of these sub‐images is decomposed into a series of multi‐resolution Gabor wavelets with multi‐orientation and multi‐scale. Second, different orientation Gabor wavelets with the same scale are fused. Next, different scale Gabor wavelets with the same orientation are fused according to the proposed fusion criterion. Third, the fusion Gabor feature histograms are calculated in each of the divided local regions. Meanwhile, every local region's information importance is measured by the proposed local image information content model. Finally, the fusion Gabor wavelet histograms are adaptively weighed by weighting map which calculated from information content model. This study conducted simulation experiments on different face databases under the different conditions including partial occlusion, expression change and illumination variation. The results indicated that the proposed LWFG algorithm is more effective with single training sample.
Close-in giant-planet formation via in-situ gas accretion and their natal disk properties
Authors: Hasegawa Yasuhiro , Yu Tze Yeung Mathew , Hansen Bradley M. S.
Published: August 2019

Aims. The origin of close-in Jovian planets is still elusive. We examine the in-situ gas accretion scenario as a formation mechanism of these planets.

Methods. We reconstruct natal disk properties from the occurrence rate distribution of close-in giant planets, under the assumption that the occurrence rate may reflect the gas accretion efficiency onto cores of these planets.

Results. We find that the resulting gas surface density profile becomes an increasing function of the distance from the central star with some structure at r ≃ 0.1 au. This profile is quite different from the standard minimum-mass solar nebula model, while our profile leads to better reproduction of the population of observed close-in super-Earths based on previous studies. We compute the resulting magnetic field profiles and find that our profiles can be fitted by stellar dipole fields (∝r−3) in the vicinity of the central star and large-scale fields (∝r−2) at the inner disk regions, either if the isothermal assumption breaks down or if nonideal magnetohydrodynamic effects become important. For both cases, the transition between these two profiles occurs at r ≃ 0.1 au, which corresponds to the period valley of giant exoplanets.

Conclusions. Our work provides an opportunity to test the in-situ gas accretion scenario against disk quantities, which may constrain the gas distribution of the minimum-mass extrasolar nebula.
Reversible Solid Oxide Cell (ReSOC) as flexible polygeneration plant integrated with CO2 capture and reuse
Authors: Buffo Giulio , Ferrero Domenico , Santarelli Massimo , Lanzini Andrea
Published: August 2019

This work presents the concept of a Reversible Solid Oxide Cell (ReSOC) system localized in an urban residential district. The system is operated as a polygeneration plant that acts as interface between the electricity grid and the local micro-grid of the district. The ReSOC plant produces hydrogen via electrolysis during periods of low electricity demand (i.e., low-priced electricity). Hydrogen is used for multiple city needs: public mobility (H2 bus fleet), electricity production delivered to the micro-grid during peak-demand hours, and heat (accumulated in a storage) provided to the local district heating (DH) network. An additional option analyzed is the use of part of the H2 to produce DME using CO2 captured from biogas obtained from municipal solid wastes. The DME is used for fueling a fleet of trucks for the garbage collection in the residential district. A traditional CO2 removal process based on liquid MEA thermally integrated with the ReSOC system is studied. A time-resolved model interfaces the steady-state operating points with the thermal storage and the loads (electrical, H2 buses, DME trucks, heat), implementing constraints of thermal and H2 self-sufficiency on the system. Neglecting the DME option, the average daily roundtrip electric efficiency is about 38%, while the annual efficiency, which includes H2 mobility and thermal energy to DH, reaches 68%. When the DME option is considered, the thermal demand for CO2 removal and conversion process reduces the heat availability for DH, while the need for additional H2 for DME synthesis increases the electricity consumption for water electrolysis: both these phenomena imply a reduction of system efficiency (-9%) proportional to DME demand.
A Test Rig for the Experimental Investigation of a MGT/SOFC Hybrid Power Plant Based on a 3kWel Micro Gas Turbine
Authors: Hohloch Martina , Herbst Melanie , Marcellan Anna , Lingstädt Timo , Krummrein Thomas , Aigner Manfred
Published: August 2019

A hybrid power plant consisting of a micro gas turbine (MGT) and a solid oxide fuel cell (SOFC) is a promising technology to reach the demands for future power plants. DLR aims to set up a MGT/SOFC hybrid power plant demonstrator based on a 3 kWel MTT EnerTwin micro gas turbine and an SOFC module with an electrical power output of 30 kWel from Sunfire. For the detailed investigation of the subsystems under hybrid conditions two separate test rigs are set up, one in which the MGT is connected to an emulator of the SOFC and vice versa. The paper introduces the set-up and the functionalities of the MGT based test rig. The special features are highlighted and the possibilities of the cyber physical system for emulation of a hybrid system are explained.
Design and setup of a low calorific SOFC off-gas combustion chamber for a pressurized MGT hybrid power plant test rig
Authors: Lingstädt Timo , Grimm Felix , Kutne Peter , Aigner Manfred
Published: August 2019

A demonstrator system for a hybrid power plant is currently being built at DLR, designed for an electrical power output level of 30 kW. Since the very low energy dense exhaust gas of the fuel cell anode side represents the fuel for the combustion chamber in this application, a low calorific SOFC off-gas combustor was developed at DLR specifically for this use case. With thorough investigations on the atmospheric test rig, the expected operational range of the combustor was quantified in preceding works. Now, a novel machine design, including dilution air with an adjustable air split configuration is derived to validate the gathered information on the micro gas turbine test rig under pressurized machine conditions. This work explains the design of the combustion system and addresses the different design features specifically implemented for this use case. Since simplifications had to be made for the atmospheric combustor prototype, a significant positive influence on the operational envelope is expected with the transition to the machine configuration.
Development of a new test rig for the analysis of hydrodynamic bearings for rotors of microGT
Authors: Niccolini Marmont Du Haut Champ Carlo Alberto , Stefani Fabrizio , Silvestri Paolo
Published: August 2019

The aim of the present work is to design a test rig suited to investigate the dynamic interaction between rotor and hydrodynamic journal bearings in micro gas turbines (microGT), i.e. with reference to small bearings (diameter in the order of ten millimeters). Particularly, the device is capable of measuring the journal location. Therefore, the journal motion due to rotor vibrations can be displayed, in order to assess performance as well as stiffness and damping of the bearings. The new test rig is based on Bently Nevada Rotor Kit (RK), but substantial modifications are carried out. Indeed, the relative radial clearance of the original RK bearings is about 2/100, while it is in the order of 1/1000 in industrial bearings. Therefore, the same RK bearings are employed in the new test rig, but a new shaft has been designed in order to reduce the original clearance. The new shaft enables us to study the bearing behaviour for different clearances, as it is equipped with interchangeable journals. The experimental data yielded by the new test rig are compared with numerical results. These are obtained by means of a suitable finite element (FEM) code developed by our research group. It allows the Thermo Elasto-HydroDynamic (TEHD) analysis of the bearing in static and dynamic conditions. In the present paper, bearing static performances are analysed in order to assess the reliability of the journal location predictions by comparing numerical and experimental results. Such comparisons are presented for both large and small clearance bearings of original and modified RK, respectively. Good agreement is found only for the modified RK equipped with small clearance bearings (relative radial clearance equal to 8/1000). Nevertheless, rotor alignment is quite difficult with small clearance bearings and a completely new test rig is designed for future experiments.
Performance Assessment of Bladeless Micro-Expanders Using 3D Numerical Simulation
Authors: Renuke Avinash , Traverso Alberto , Pascenti Matteo
Published: August 2019

This paper summarizes the development of fully 3D Computational Fluid Dynamics (CFD) analysis for bladeless air micro expander for 200 W and 3 kW rated power. Modelling of nozzle along with rotor is done using structured mesh. This analysis, for the first time, demonstrates the interaction between nozzle and rotor using compressible flow density-based solver. The Shear Stress Transport (SST) turbulence model is employed to resolve wall effects on the rotor and to determine the shear stress accurately. The results illustrate the flow field inside stator and rotor along with complicated mixing zone between stator and rotor. The comparison of rotor-stator CFD simulation results is done with experiments to preliminary validate the model. The losses in the turbine are discussed with the help of experimental and numerical data.
“Talking Phonics for Autism”: Developing A Multi-Purpose Touch Screen Technology Software Application Which Utilizes Sound Articulation Point to Teach Autistic Children
Authors: Basir Noriha , Mohamad Hashim Ameer Fuhaili , Abdullah Sharmini , Abdul Rahim Noor Asliza , Sabri Masturah , Yusuf Afifah Hanani , Harun Wan Norhaizar , Buragohain Dipima
Published: August 2019

This paper aims to examine the potentials of the multi-purpose touch screen technology application which utilizes a sound articulation point software called "TALKING PHONICS FOR AUTISM"as an alternative method of teaching phonics to autistic children. "TALKING PHONICS FOR AUTISM"is developed via a collaborative effort between the Centre of International Languages (CIL) and the School of Human Development and techno Communication (iKOM), University Malaysia Perlis (UniMAP). The reading skills of autism children are developed intofive (5) levels ofMalay reading comprehension skills. The first level consists of open syllables - vowels and consonants. The following consecutivethree levels comprised of closed syllables. The fourth level introduces vocal sequence while the fifth level constitutes of Malay language loans. The Malay-language dialect phonological theory by Tajul Aripin Kassin (2000) which is based on Clements &Keysher's (1980) Generative Booking Generic Fonology Model (CV) forms the theorectical framework of this paper.
Case study in training of diagnostics of mechanisms of psychological defense in a conflict situation
Authors: Sivrikova Nadezhda , Ptashko Tatyana , Chernikova Elena , Perebeynos Artem , Roslyacova Svetlana , Moiseyeva Elena
Published: August 2019

The relevance of a research is dictated by need of training of specialists in the field of management of the conflicts. Researchers recognize need of development of skills of overcoming barriers of effective resolution of conflicts. Defense mechanisms are such barriers. Creation a case study of training of definition of defense mechanisms in a conflict became a research objective. First, cases of video were created. Secondly, the scheme of the analysis of manifestations of mechanisms of protection in the conflict was created. The created cases were used for training of future specialists in management of the conflicts (23 people). The experimental plan with pre-post-testing and control group (13 people) was used for approbation of the created case study. Results of approbation a case study showed that it is an effective technique of formation of skills of definition of defense mechanisms in a conflict situation.
Features of the personality of the people identifying themselves with different generations
Authors: Sivrikova Nadezhda , Artemyeva Natalya , Sokolova Nadezhda , Moiseyeva Elena , Borodina Vera , Terekhov Anton
Published: August 2019

The issue of existence of real differences between generations is actively discussed by researchers. The discussion which is conducted in scientific community does not manage to respond to the practice request. Therefore, differences between generations need scientific studying. The purpose of this research is consisted in comparison of personal features of the Russians identifying themselves with different generations (Post-war, Soviet, Transitional and Post-Soviet). 212 people participated in a research. The generational identity of the people was decided upon the direct question of what generation they associate themselves with. The Russianspeaking version of the short questionnaire of the Big five (TIPI) was applied to studying of features of the identity of participants of a research. The obtained data confirm the idea that the representatives of the senior generations and the younger generations are more focused on collectivism values and on individualism values respectively.
“The Little Architects” workshop an active learning and teaching method for children in need
Authors: Povian Cristina Maria
Published: August 2019

One of the European Commission's priorities in education is to reduce early school leaving to less than 10% across European countries by 2020. If, in some Member States, progress in effective policies is satisfactory in 2018, many countries are still far from achieving goal. Unfortunately, Romania is in the category which still has problems with this situation. The aim of this article is to analyze a case of educational program that uses active learning and teaching methods with children in need from rural areas of Romania. For almost ten years, the nongovernmental association "Alternative Education" organized summer schools for children in Timiș County. The paper describes and analyzes the creative workshop "The Little Architects", used by this association for the first time in the activities of the summer school in 2018, and presents the benefits of using active learning methodology in order to attract children to school and improve the percentage of early school leavers.
Reforms of the higher education system in Poland since 1989. Between tradition and challenges of the 21st century
Authors: Wojniak Justyna , Majorek Marta
Published: August 2019

The paper discusses changes within the academia in the context of political, social and economic transformation of 1989 in Poland. The considerations are based on the views and aims of higher education reflected in the university reforms that were undertaken between 1990 and 2018. The study is focused on political background of the reform concepts and on the regulations that were introduced, as well as on the contemporary trends shaping the education processes. The authors attempt to answer the question concerning the influence of Polish transformation process on the traditional mission of the university and its specific social and cultural role.
Global field, local approach − 20th century Polish education comparativists and their works
Authors: Włoch Anna , Wojniak Justyna
Published: August 2019

Comparative education as a pedagogical subdiscipline has developed in Poland in close connection with the history of education from the very beginning. The paper analyzes the main publications of leading Polish pedagogues of the 20th century, and the research has been based on source analysis. The aim of the paper is to present the achievements of Polish comparativists of 20th century and their contribution to the development of comparative education as a global field of research. The authors attempt to answer the question concerning the political context of Polish 20th century education comparativists' work, as scientific activity in Middle and Eastern Europe after World War II was strongly involved in political and. ideological terms. The result of the research is an indication of the participation of Polish pedagogues in an international community of researchers and Polish contribution to the development of comparative pedagogy as a scientific discipline.
The importance of using mannequin-training models in first aid learning: Case of avulsed tooth
Authors: Dolenc Eva , Slabe Damjan
Published: August 2019

The avulsion of permanent teeth is one of the most serious dental injuries, and correct emergency management is very important for the prognosis. Students of health care must be able to manage such emergency cases properly. Practical skill training on models can significantly improve the performance of students prior to the transition to a real patient. In Slovenia at the Faculty of Health Sciences at the University of Ljubljana, students get knowledge in the field of first aid, including tooth damage. The purpose is to evaluate the effectiveness of first aid training in case of teeth avulsion based on the mannequin-training model. Data collection took place in the context of experimental research methods. A group of students, who practice with the help of the mannequin-training model is better prepared to give first aid in case of tooth avulsion if the accident really happens, compared to a group that was studying without the model.
Gamification of design process in interior architecture education: Who? with whom? where? how?
Authors: Aşkın Gülsüm Damla
Published: August 2019

The design process in Interior Architecture education is the basis of all the studio courses and design-oriented courses. In this process, it is important for students to develop their creative thoughts and find different ideas. Students find it difficult to produce creative design ideas. As well as producing ideas, students also have difficulty in determining problem status and performing user analysis. In this respect, implementation of different methods and activities are important in the process. One of these methods is the integration of gamification into the design education. This education method was conducted as a workshop with a group of Interior Design students during the Spring term of 2018–2019 in İstanbul Şehir University. The students who took the project course for the first time were included in the research. In the workshop, firstly, the game ”Who? With Whom? Where? How?" was played manually, and the user ID was defined. Secondly, the results of the game were converted to the function scheme. After the study, a survey was conducted with the students. It was observed that the method of gamification increased the motivation of the students and offered more than one alternative in design process compared to the traditional thinking methods.
Den Stau beseitigen
Authors: Corts Magga
Published: August 2019

Ein dynamischer Austausch zwischen Organzellen und ihrer Umgebung gewährleistet eine physiologische Organfunktion. Es finden zahlreiche Prozesse statt, um negative Einflüsse auszugleichen und Homöostase aufrechtzuerhalten. Das Grundsystem impliziert die Endstrombahn, Bindegewebszellen und Nervenenden. Es reguliert das Zell-Milieu-Zusammenspiel. Eine funktionelle extrazelluläre Flüssigkeit ist eine Voraussetzung hierfür. Wenn arterielle, venöse, nervale oder lymphatische Zirkulationssysteme gestört sind, können sich verschiedene Krankheitsbilder entwickeln. Osteopathische Techniken bilden einen unterstützenden Therapiebaustein.
Decoration of Fibrin with Extracellular Chaperones
Authors: Talens Simone , Leebeek Frank W. G. , Veerhuis Robert , Rijken Dingeman C.
Published: August 2019

Background Many proteins bind to fibrin during clot formation in plasma. We previously identified by mass spectrometry the most abundant proteins that noncovalently bind to fibrin clots. Several of these proteins (e.g., apolipoprotein J/clusterin, haptoglobin, α2-macroglobulin, α1-antitrypsin) can act as extracellular chaperones.

Objective We hypothesize that clot-binding proteins may interact with fibrin as chaperones. The goal of this study is to test this hypothesis and to investigate the origin of the cross-β or amyloid structures in fibrin clots, which are associated with protein unfolding.

Methods and Results A thioflavin T assay was used to detect cross-β structures. A steadily increasing amount was measured in the fibrinogen fraction of plasma during heat stress, a standard treatment to induce unfolding of proteins. Heat-stressed plasma was clotted and clot-bound proteins were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The results showed that the amounts of the clot-bound proteins were related to the duration of the heat stress. This indicates that cross-β structures in unfolded fibrin(ogen) are involved in clot binding of the proteins, which supports our chaperone hypothesis. A contributing role of fibrin formation itself was studied by clotting purified fibrinogen with thrombin in the presence of thioflavin T. The fluorescence intensity increased in time in the presence of thrombin, but did not increase in its absence. This provides evidence for the generation of cross-β structures during fibrin formation.

Conclusion Fibrin clots generated in plasma are decorated with extracellular chaperones. The binding of these chaperones involves cross-β structures originating both from unfolded fibrinogen and from fibrin formation.
A versatile dark-field acoustic-resolution photoacoustic microscopy system aided by 3D printing
Authors: Wen Chenyao , Zhao Lingyi , Han Tao , Li Wenzhao , Zhang Guangjie , Li Changhui
Published: August 2019

Since the dark-field acoustic-resolution photoacoustic microscopy (AR-PAM) was invented over one decade ago, its powerful imaging capability made this system successful. In this work, we designed and tested an AR-PAM system whose key parts are relied on 3D printing and fiber bundles. This new design not only makes it much simpler to develop a robust PAM system, but also the illumination angle is adjustable to aid for different applications. Our simulation study and phantom experiments demonstrated that this design has the comparable performance with traditional dark-field AR-PAM.
Discussing the extension and applications of a variational approach with deformed derivatives
Authors: Leopoldino Andressa P. C. , Weberszpil José , Godinho Cresus F. L. , Helayël-Neto José Abdalla
Published: August 2019

One has recently presented an extension of the standard variational calculus to include the presence of deformed derivatives, both in the Lagrangian of systems of particles and in the Lagrangian density of field-theoretic models. Classical Euler-Lagrange equations and the Hamiltonian formalism have been reassessed in this approach. Whenever applied to a number of physical systems, the resulting dynamical equations come out to be the correct ones found in the literature, especially with mass-dependent and with nonlinear equations for classical and quantum-mechanical systems. In the present contribution, one extends the variational approach, including a piecewise form of deformed derivatives to study higher-order dissipative systems and to obtain, as an option, deformed equations as well. Applications to concrete situations are contemplated, such as an accelerated point charge—this is the problem of the Abraham-Lorentz-Dirac force—stochastic dynamics like the Langevin, the advection-convection-reaction and Fokker-Planck equations, the Korteweg-de Vries equation, the Landau-Lifshitz-Gilbert problem, and the Caldirola-Kanai Hamiltonian and heat transfer equation of the Fourier and non-Fourier types. By considering these different examples, it is shown that the formulation proposed in this paper may be a simple, but promising, path for dealing, for example, with dissipative, nonlinear, stochastic systems and the anomalous heat transfer problem, by adopting a variational approach.
Fermi surface complexity, effective mass, and conduction band alignment in n-type thermoelectric Mg3Sb2 – xBix from first principles calculations
Authors: Zhang Jiawei , Iversen Bo Brummerstedt
Published: August 2019

Using first principles calculations, we study the conduction band alignment, effective mass, and Fermi surface complexity factor of n-type Mg3Sb2 – xBix (x = 0, 1, and 2) from the full ab initio band structure. We find that with an increase in the Bi content, the K and M band minima move away from the conduction band minimum CB1 while the singly-degenerate Г band minimum shifts rapidly downward and approaches the conduction band minimum. However, the favorable sixfold degenerate CB1 band minimum keeps dominating the conduction band minimum and there is no band crossing between the Г and CB1 band minima. In addition, we show that the connection of the CB1 carrier pockets with the energy level close to the band minimum M can strongly enhance the carrier pocket anisotropy and Fermi surface complexity factor, which is likely the electronic origin for the local maximum in the theoretical power factor. Our calculations also show that the density of states effective mass, Seebeck coefficient, and Fermi surface complexity factor decrease with an increase in the Bi content, which is unfavorable to the electrical transport. In contrast, reducing the conductivity effective mass with an increase in the Bi content is beneficial to the electrical transport by improving carrier mobility and weighted mobility as long as the detrimental bipolar effect is insignificant. As a result, in comparison with n-type Mg3Sb2, n-type Mg3SbBi shows higher power factors and a much lower optimal carrier concentration for the theoretical power factor at 300 K, which can be easily achieved by the experiment.
Thermal collapse of a skyrmion
Authors: Derras-Chouk Amel , Chudnovsky Eugene M. , Garanin Dmitry A.
Published: August 2019

Thermal collapse of an isolated skyrmion on a two-dimensional spin lattice has been investigated. The method is based upon solution of the system of stochastic Landau-Lifshitz equations for up to 104 spins. The recently developed pulse-noise algorithm has been used for the stochastic component of the equations. The collapse rate follows the Arrhenius law. Analytical formulas derived within a continuous spin-field model support numerically-obtained values of the energy barrier. The pre-exponential factor is independent of the phenomenological damping constant that implies that the skyrmion is overcoming the energy barrier due to the energy exchange with the rest of the spin system. Our findings agree with experiments, as well as with recent numerical results obtained by other methods.
Scattering off molecules far from equilibrium
Authors: Yong Haiwang , Ruddock Jennifer M. , Stankus Brian , Ma Lingyu , Du Wenpeng , Goff Nathan , Chang Yu , Zotev Nikola , Bellshaw Darren , Boutet Sébastien , Carbajo Sergio , Koglin Jason E. , Liang Mengning , Robinson Joseph S. , Kirrander Adam , Minitti Michael P. , Weber Peter M.
Published: August 2019

Pump-probe gas phase X-ray scattering experiments, enabled by the development of X-ray free electron lasers, have advanced to reveal scattering patterns of molecules far from their equilibrium geometry. While dynamic displacements reflecting the motion of wavepackets can probe deeply into the reaction dynamics, in many systems, the thermal excitation embedded in the molecules upon optical excitation and energy randomization can create systems that encompass structures far from the ground state geometry. For polyatomic molecular systems, large amplitude vibrational motions are associated with anharmonicity and shifts of interatomic distances, making analytical solutions using traditional harmonic approximations inapplicable. More generally, the interatomic distances in a polyatomic molecule are not independent and the traditional equations commonly used to interpret the data may give unphysical results. Here, we introduce a novel method based on molecular dynamic trajectories and illustrate it on two examples of hot, vibrating molecules at thermal equilibrium. When excited at 200 nm, 1,3-cyclohexadiene (CHD) relaxes on a subpicosecond time scale back to the reactant molecule, the dominant pathway, and to various forms of 1,3,5-hexatriene (HT). With internal energies of about 6 eV, the energy thermalizes quickly, leading to structure distributions that deviate significantly from their vibrationless equilibrium. The experimental and theoretical results are in excellent agreement and reveal that a significant contribution to the scattering signal arises from transition state structures near the inversion barrier of CHD. In HT, our analysis clarifies that previous inconsistent structural parameters determined by electron diffraction were artifacts that might have resulted from the use of inapplicable analytical equations.
Interpreting the electron temperature inferred from x-ray continuum emission for direct-drive inertial confinement fusion implosions on OMEGA
Authors: Cao D. , Shah R. C. , Regan S. P. , Epstein R. , Igumenshchev I. V. , Gopalaswamy V. , Christopherson A. R. , Theobald W. , Radha P. B. , Goncharov V. N.
Published: August 2019

In this paper, we present a theoretical framework for interpreting the hot-spot electron temperature (Te) inferred from hard (10- to 20-keV) x-ray continuum emission for inertial confinement fusion implosions on OMEGA. We first show that the inferred Te represents the emission-weighted, harmonic mean of the hot-spot Te distribution, both spatially and temporally. A scheme is then provided for selecting a photon energy of which the emission weighting approximates neutron weighting. Simulations are then used to quantify the predicted relationship between the inferred Te, neutron-weighted Ti, and implosion performance on OMEGA. In an ensemble of 1-D simulations, it was observed that hot-spot thermal nonequilibrium precluded a sufficiently unique mapping between the inferred Te and neutron-weighted Ti. The inferred Te and hard x-ray yield's sensitivity to implosion asymmetry was studied using a 3-D simulation case study with low-harmonic-mode perturbations (i.e., laser beam power imbalance, target offset, and beam port geometry departures from spherical symmetry) and laser imprint (lmax = 200).
Charge transport mechanism in periodic mesoporous organosilica low-k dielectric
Authors: Gismatulin A. A. , Gritsenko V. A. , Seregin D. S. , Vorotilov K. A. , Baklanov M. R.
Published: August 2019

Periodic mesoporous organosilicas are promising insulating materials for multilevel interconnects of integrated circuits because of their unique structural and mechanical properties. Therefore, understanding of their electrical characteristics, particularly the charge transport mechanism, is important. It is generally accepted that the thin dielectric film charge transport is limited by the Frenkel effect. In our work, the charge transport of the periodic mesoporous organosilica structure is analyzed with four volume-limited charge transport models. It is established that the Frenkel model of Coulomb trap ionization, the Hill-Adachi model of overlapping Coulomb potentials and the Makram-Ebeid and Lannoo model of multiphonon isolated traps ionization quantitatively, do not describe the charge transport of the periodic mesoporous organosilica low-k dielectric. The Nasyrov-Gritsenko model gives a consistent explanation of the charge transport of the periodic mesoporous organosilica low-k structure at different temperatures with the trap concentration N = 5.4 × 1020 cm−3 and effective mass m* = 0.82 me. The thermal trap energy Wt = 1.6 eV and the optical trap energy Wopt = 3.2 eV obtained from the simulation by the Nasyrov-Gritsenko model correspond to the Si-Si defect.
The significance of grain morphology and moisture content on the response of silica sand to ballistic penetration
Authors: Perry J. I. , Braithwaite C. H. , Taylor N. E. , Jardine A. P.
Published: August 2019

The dynamic response of sand is of interest for a wide range of applications, from civil engineering to asteroid impact, in addition to defense and industrial processes. Granular dynamics are controlled by a complex network of intergrain force chains; yet, our understanding of how grain morphology, moisture, rate, and loading geometry affect the response to rapid compaction remains limited. Here, we show how just 1% moisture can significantly reduce penetration resistance in silica sand, while smoother-grained material—with a similar bulk density, grain size, and mineralogy—exhibits markedly improved stopping power. Cylindrical targets are impacted by spherical steel projectiles, with Digital Speckle Radiography employed to determine both the penetration depth and the sand bed displacement at a series of incremental time steps after impact. The results provide substantial insight into how slight adjustments to grain-grain contact points can affect the bulk dynamic response of brittle granular materials.
Isothermal adsorption of polyampholytes on charged nanopatterned surfaces
Authors: Bakhshandeh Amin , dos Santos Alexandre P. , Diehl Alexandre , Levin Yan
Published: August 2019

We investigate the adsorption of neutral polyampholytes on charged nanopatterned surfaces. The surfaces have charged domains but are overall neutral. To perform efficient simulations, we use an approach which combines the explicit form of the interaction potential between the polyampholyte monomers and the surface with a 3d Ewald summation method. We observe that the amount of adsorption and the structure of the adsorbed polyampholytes depend strongly on the surface pattern, the relative size of the surface domains, and the charge distribution along the polyampholyte backbone.
Carboxylated carbon nanotubes-graphene oxide aerogels as ultralight and renewable high performance adsorbents for efficient adsorption of glyphosate
Authors: Liu Hao , Wang Xueying , Ding Chaofan , Dai Yuxue , Sun Yuanling , Lin Yanna , Sun Weiyan , Zhu Xiaodong , Han Rui , Gao Dandan , Luo Chuannan
Published: August 2019

Environmental contextGlyphosate is a highly effective and widely used organophosphorus pesticide, but its residues can harm the environment and human health. We report a carboxylated carbon nanotubes-graphene oxide aerogel that can efficiently remove glyphosate from water. This technology has great application prospects in dealing with water contaminated with glyphosate.
AbstractGlyphosate, an organophosphorus pesticide, has received considerable attention in recent years owing to its carcinogenic potency. The technologies that remove glyphosate in the environment, especially in water, are important. In this work, we prepare a carboxylated carbon nanotubes-graphene oxide aerogel (cCNTs-GA) by the freeze-drying method for the adsorption of glyphosate. The prepared aerogel exhibits an ultra-low density (7.30mgcm−3), good morphology and strong mechanical strength. Meanwhile, a NaOH solution (0.5molL−1) is selected as an eluent and the adsorption parameters for the adsorption of glyphosate are optimised. The properties of the adsorbents after multiple repetitions and the adsorption mechanism of the cCNTs-GA are also studied. The results show that the adsorbent can be recycled more than 20 times and maintains a good adsorption performance. The maximum adsorption capacity of glyphosate at pH 3 is calculated from the Langmuir isotherm model (546mgg−1 at the temperature of 298K), and the cCNTs-GA exhibits a high adsorption affinity and adsorption capacity for glyphosate, as determined by the partition coefficient (PC). The pseudo-second-order kinetic model fits well to the dynamic behaviour. The equilibrium adsorption process follows the Langmuir isotherm model and the adsorption process is mainly controlled by the intraparticle diffusion model. Furthermore, thermodynamic analysis indicates that the adsorption of glyphosate on the cCNTs-GA is exothermic and spontaneous. The adsorbent is used to remove glyphosate from waste water and the adsorption capacity of the cCNTs-GA for glyphosate is higher than other adsorbents, which indicates that the developed adsorbent has a great potential application in environmental pollution treatment.
World Health Organization Global Gonococcal Antimicrobial Surveillance Program (WHO GASP): review of new data and evidence to inform international collaborative actions and research efforts
Authors: Unemo Magnus , Lahra Monica M. , Cole Michelle , Galarza Patricia , Ndowa Francis , Martin Irene , Dillon Jo-Anne R. , Ramon-Pardo Pilar , Bolan Gail , Wi Teodora
Published: August 2019

Antimicrobial resistance (AMR) in Neisseria gonorrhoeae is a serious public health problem, compromising the management and control of gonorrhoea globally. Resistance in N. gonorrhoeae to ceftriaxone, the last option for first-line empirical monotherapy of gonorrhoea, has been reported from many countries globally, and sporadic failures to cure especially pharyngeal gonorrhoea with ceftriaxone monotherapy and dual antimicrobial therapies (ceftriaxone plus azithromycin or doxycycline) have been confirmed in several countries. In 2018, the first gonococcal isolates with ceftriaxone resistance plus high-level azithromycin resistance were identified in England and Australia. The World Health Organization (WHO) Global Gonococcal Antimicrobial Surveillance Program (GASP) is essential to monitor AMR trends, identify emerging AMR and provide evidence for refinements of treatment guidelines and public health policy globally. Herein we describe the WHO GASP data from 67 countries in 2015–16, confirmed gonorrhoea treatment failures with ceftriaxone with or without azithromycin or doxycycline, and international collaborative actions and research efforts essential for the effective management and control of gonorrhoea. In most countries, resistance to ciprofloxacin is exceedingly high, azithromycin resistance is present and decreased susceptibility or resistance to ceftriaxone has emerged. Enhanced global collaborative actions are crucial for the control of gonorrhoea, including improved prevention, early diagnosis, treatment of index patient and partner (including test-of-cure), improved and expanded AMR surveillance (including surveillance of antimicrobial use and treatment failures), increased knowledge of correct antimicrobial use and the pharmacokinetics and pharmacodynamics of antimicrobials and effective drug regulations and prescription policies (including antimicrobial stewardship). Ultimately, rapid, accurate and affordable point-of-care diagnostic tests (ideally also predicting AMR and/or susceptibility), new therapeutic antimicrobials and, the only sustainable solution, gonococcal vaccine(s) are imperative.
Corrigendum to: The effect of woody fuel characteristics on fuel ignition and consumption: a case study from a eucalypt forest in south-west Western Australia
Authors: Hollis J. J. , McCaw W. L. , Cruz M. G.
Published: August 2019

Coarse woody debris (>0.6cm in diameter) is an important component of the fuel complex in Australian eucalypt forests, influencing both fire behaviour, smoke production and post-fire ecological processes. We investigated how physical characteristics of woody fuel affected ignition and consumption during an experimental fire where the fuel complex characteristics, fire weather and fire behaviour varied within a narrow range. Decay status, bark condition, arrangement, suspension and extent of charring were classified for 2866 coarse woody fuel particles. We used generalised linear model (GLM) analysis to explain ignition success and the extent of consumption of individual particles, with a focus on larger diameter fuels (>7.5cm in diameter), which comprised 83% of the woody fuel load and 94% of the woody fuel consumed during the flaming and smouldering stages of combustion. Ignition success was best explained by a model that included fuel arrangement (a surrogate of fuel proximity), suspension and decay status. The extent of fuel consumption was greater for pieces in advanced stages of decay, but suspension (inversely related) and arrangement (directly related) also affected the outcome. Forest management practices, previous fire history and other natural disturbances are likely to influence the distribution of pre-fire diameters and suspension classes that characterise large woody fuels at a site, and will therefore influence woody fuel consumption. This has practical implications for quantifying heat release and atmospheric emissions from fires burning in forests with different management histories.
Rolling back the right to strike: amendments to South Africa’s Labour Relations Act and their implications for working-class struggle
Authors: Runciman Carin
Published: August 2019

The South African National Assembly recently passed amendments to the Labour Relations Act which will roll back the right to strike. This briefing will analyse the amendments, their implications and what they tell us about the state of the labour movement, the possibilities for trade union revival and the state working-class struggle in South Africa today.
Research on the Dynamic Characteristics of the High Air Speed Nozzle in Isentropic Flow
Authors: Xiang Dong , Wang Yingting , Li Chenjing
Published: August 2019

The application of microsatellites has been development with the continuous expansion of space missions in resents years. The microsatellites have several characteristics such as light weight, small size and low cost. The platform flotation table is one of the simulation ways on the ground. With the continuous development of space technology, satellite ground simulation platform flotation table as a key technology which attracts lots of researchers. In this paper, the highspeed nozzle has been analyzed based on the research of Laval nozzle. The state of shock waves can be researched by the Laval nozzle and the air speed from the nozzle can be calculated. The flow field of the high speed nozzle has been simulation by the FLUENT software. The nozzle mode has been built by the GAMBIT and the model is meshed in structured grid. The simulation result shows that the air in the nozzle has many speeds in different place. The stable speeds are 390 m/s and 150m/s in the larynx and trailing end position.The maximum are reached into the nozzle and the speed is 578m/s, which is deviated from the theoretical analysis. At the constant pressure of 4 bar, the mass of nozzle flow is 0.000318758 kg/s. The mass of outlet flow is 0.000318798 kg/s, and the calculation error is 10-8. The thrust of the nozzle is also stable at 3ms, and its stability value is 50.1 mN. The maximum force of the outlet is 176 mN before the nozzle reaches stability. The simulation result can guided for the nozzle design and itis more significance for the high precision control and measurement of nozzles.
Modeling Investigation of Concurrent-flow Chemical Extraction Process
Authors: Nie Miaomiao , Tan Jing , Deng Wen-Sheng , Su Yue-Feng
Published: August 2019

In this study, modeling investigation of mass transfer in concurrent-flow chemical extraction process is carried out. Continuum Model is used to describe mass transfer process. Concentration curves in organic droplet and aqueous liquid film are firstly calculated and rate-limiting step is determined to be mass transfer of solute in aqueous phase. Mass transfer performance in aqueous phase is further calculated. Volumetric mass transfer coefficient and volumetric mass transfer coefficient during mass transfer time before solute concentration decreases to 5%, are calculated for evaluating mass transfer characteristics. The effect of organic droplet size is studied. The result demonstrates that increase in aqueous/organic volume ratio significantly decreases mass transfer performance, decrease in droplet size enhances mass transfer process through both reducing mass transfer resistance and increasing contacting area.