bluuebunny/crossref_metadata_2025 huggingface dataset:
Study of GSLT in Curvature-Matter Coupling Gravity
Authors: Sharif Muhammad , Ikram Ayesha
Published: January 2018

In this work, we study the first and generalized second laws of thermodynamics at the apparent horizon of homogeneous and isotropic universe model in the context of f (G, T) gravity (G and T represent the Gauss-Bonnet invariant and trace of the energymomentum tensor, respectively). We formulate the corresponding field equations as well as determine the radius, temperature and entropy to analyze these laws. An extra term associated with entropy production is appeared in the first law due to the non-equilibrium treatment of thermodynamics. It is found that the universal condition is obtained to preserve the generalized second law of thermodynamics.
Entropy in Spacetime and Topological Hair
Authors: Hyun Young-Hwan , Kim Yoonbai
Published: January 2018

Global topological soliton of the hedgehog ansatz is added to de Sitter spacetime in arbitrary dimensions larger than three, and then thermodynamic law is checked at the cosmological horizon. All geometric and thermodynamic quantities are varied in the presence of a long-range interacting matter distribution with negative pressure, however the entropy-area relation is satisfied in the exact form. Its geometry involves deficit solid angle but maintains a single horizon which allows unique temperature normalization, different from the case of Schwarzschild-de Sitter spacetime.
Throat quantization of the Schwarzschild-Tangherlini(-AdS) black hole
Authors: Maeda Hideki
Published: January 2018

By the throat quantization pioneered by Louko and Mäkelä, we derive the mass and area/entropy spectra for the Schwarzschild-Tangherlini-type asymptotically flat or AdS vacuum black hole in arbitrary dimensions. Using the WKB approximation for black holes with large mass, we show that area/entropy is equally spaced for asymptotically flat black holes, while mass is equally spaced for asymptotically AdS black holes. Exact spectra can be obtained for toroidal AdS black holes in arbitrary dimensions including the three-dimensional BTZ black hole.
The first ICRANet catalog of binary-driven hypernovae
Authors: Pisani G. B. , Ruffini R. , Aimuratov Y. , Bianco C. L. , Karlica M. , Kovacevic M. , Moradi R. , Muccino M. , Penacchioni A. V. , Primorac D. , Rueda J. A. , Wang Y.
Published: January 2018

In a series of recent publications, scientists from ICRANet, led by professor Remo Ruffini, have reached a novel comprehensive picture of gamma-ray bursts (GRBs) thanks to their development of a series of new theoretical approaches. Among those, the induced gravitational collapse (IGC) paradigm explains a class of energetic, long-duration GRBs associated with Ib/c supernovae (SN), recently named binary-driven hypernovae (BdHNe).

BdHNe have a well defined set of observational features which allow to identify them. Among them, the main two are: 1) long duration of the GRB explosion, namely larger than 2 s in the rest frame; 2) a total energy, released in all directions by the GRB explosion, larger than 1052 ergs.

A striking result is the observation, in the BdHNe sources, of a universal late time power-law decay in the X-rays luminosity after 104 s, with typical decaying slope of ~ 1.5. This leads to the possible establishment of a new distance indicator having redshift up to z ~ 8.

Thanks to this novel theoretical and observational understanding, it was possible for ICRANet scientists to build the firstst BdHNe catalog, composed by the 345 BdHNe identified up to the end of 2016.
Baryonic Force for Accelerated Cosmic Expansion and Generalized U1b Gauge Symmetry in Particle-Cosmology
Authors: Khan Mehbub , Hao Yun , Hsu Jong-Ping
Published: January 2018

Based on baryon charge conservation and a generalized Yang-Mills symmetry for Abelian (and non-Abelian) groups, we discuss a new baryonic gauge field and its linear potential for two point-like baryon charges. The force between two point-like baryons is repulsive, extremely weak and independent of distance. However, for two extended baryonic systems, we have a dominant linear force α r. Thus, only in the later stage of the cosmic evolution, when two baryonic galaxies are separated by an extremely large distance, the new repulsive baryonic force can overcome the gravitational attractive force. Such a model provides a gauge-field-theoretic understanding of the late-time accelerated cosmic expansion. The baryonic force can be tested by measuring the accelerated Wu-Doppler frequency shifts of supernovae at different distances.
Quintessential inflation: A unified scenario of inflation and dark energy
Authors: Hossain Wali
Published: January 2018

Quintessential inflation unifies inflation and late time acceleration by a single scalar field. Such a scenario, with canonical and non-canonical scalar fields, has been discussed. The scalar field behaves as an inflaton field during inflation and as a quintessence field during late time. Also the predictions of the models has been compared with the recent Planck data.
GRB 110731A within the IGC paradigm
Authors: Primorac Daria , Ruffini Remo , Pisani Giovanni Battista , Aimuratov Yerlan , Biancol Carlo Luciano , Karlica Mile , Melon Fuksman Julio David , Moradi Rahim , Muccino Marco , Penacchioni Ana Virginia , Rueda Jorge Armando , Wang Yu
Published: January 2018

Bright gamma-ray burst (GRB) 110731A was simultaneously observed by Fermi and Swift observatories, with a follow up optical observation which inferred the redshift of z = 2.83. Thus, available data are spanning from optical to high energy (GeV) emission. We analyze these data within the induced gravitational collapse (IGC) paradigm, recently introduced to explain temporal coincidence of some long GRBs with type Ic supernovae. The case of binary-driven hypcrnova (BdHN) assumes a close system, which starts as an evolved core - neutron star binary. After the core-collapse event, the new NS - black hole system is formed, emitting the GRB in the process. We performed the time-resolved and time-integrated analysis of the Fermi data. Preliminary results gave isotropic energy Eiso = 6.05 × 1053 erg and the total P-GRB energy of Ep–GRB = 3.7 × 1052 erg. At transparency point we found a Lorentz factor Γ ~ 2.17 × 103 laboratory radius of 8.33 x 1013 cm, P-GRB observed temperature of 168 keV and a baryon load B = 4.35 × 10-4. Simulated light-curve and prompt emission spectra showed the average circum burst medium density to be n ~ 0.03 particles per cm3. We reproduced the X-ray light-curve within the rest-frame of the source, finding the common late power-law behavior, with α = –1.22. Considering these results, we interpret GRB 110731A as a member of a BdHNe group.
Equation of state with scale-invariant hidden local symmetry and gravitational waves
Authors: Lee Hyun Kyu
Published: January 2018

The equation of state (EoS) for the effective theory proposed recently in the frame work of the scale-invariant hidden local symmetry is discussed briefly. The EoS is found to be relatively stiffer at lower density and but relatively softer at higher density. The particular features of EoS on the gravitational waves are discussed. A relatively stiffer EoS for the neutron stars with the lower density induces a larger deviation of the gravitational wave form from the point-particle-approximation. On the other hand, a relatively softer EoS for the merger remnant of the higher density inside might invoke a possibility of the immediate formation of a black hole for short gamma ray bursts or the appearance of the higher peak frequency for gravitational waves from remnant oscillations. It is anticipated that this particular features could be probed in detail by the detections of gravitational waves from the binary neutron star mergers.
Colliding scalar pulses in the Einstein-Gauss-Bonnet gravity
Authors: Shinkai Hisaaki , Torii Takashi
Published: January 2018

We numerically investigated how the nonlinear dynamics depends on the dimensionality and on the higher-order curvature corrections in the form of Gauss-Bonnet (GB) terms, with a model of colliding scalar pulses in plane-symmetric space-time. We observed that a collision of large scalar pulses will produce a large-curvature region, of which the magnitude depends on αGB. The normal corrections (αGB > 0) work for avoiding the appearance of singularity, although it is inevitable.
New Views on Dark Matter from Emergent Gravity
Authors: Sun Sichun , Zhang Yun-Long
Published: January 2018

We discuss a scenario that apparent dark matter comes from the induced gravity in the (3+1)- dimensional spacetime, which can be embedded into one higher dimensional flat spacetime. The stress tensor of dark energy and dark matter is identified with the Brown-York stress tensor on the hypersurface, and we find an interesting constraint relation between the dark matter and dark energy density parameter and baryonic density parameter. Our approach may show a new understanding for Verlinde’s emergent gravity from higher dimensions. We also comment on some phenomenological implications, including gravitational wave solutions and MOND limit.
Bell Inequality from Holographic Gravity
Authors: Sun Sichun , Zhang Yun-Long
Published: January 2018

We study a holographic model of an EPR pair at the boundary of bulk gravity, and use Bell inequality as a sharp test of entanglement. By revealing how Bell inequality is violated by gravity in the bulk, our study sheds light on the entanglement of the original ER=EPR conjecture.
Exact Holography of Massive M2-brane Theories and Entanglement Entropy
Authors: Jang Dongmin , Kim Yoonbai , Kwon O-Kab , Tolla D. D.
Published: January 2018

We test the gauge/gravity duality between the N = 6 mass-deformed ABJM theory with Uk(N) × U-k(N) gauge symmetry and the 11-dimensional supergravity on LLM geometries with SO(4)=ℤk × SO(4)=ℤk isometry. Our analysis is based on the evaluation of vacuum expectation values of chiral primary operators from the supersymmetric vacua of mass-deformed ABJM theory and from the implementation of Kaluza-Klein (KK) holography to the LLM geometries. We focus on the chiral primary operator (CPO) with conformal dimension Δ = 1. The non-vanishing vacuum expectation value (vev) implies the breaking of conformal symmetry. In that case, we show that the variation of the holographic entanglement entropy (HEE) from it’s value in the CFT, is related to the non-vanishing one-point function due to the relevant deformation as well as the source field. Applying Ryu Takayanagi’s HEE conjecture to the 4-dimensional gravity solutions, which are obtained from the KK reduction of the 11-dimensional LLM solutions, we calculate the variation of the HEE. We show how the vev and the value of the source field determine the HEE.
Stability Analysis of Bulk Viscous Cosmology
Authors: Sharif M. , Mumtaz Saadia
Published: January 2018

In this paper, we study phase space analysis of FRW universe model by taking a power-law model for bulk viscosity coefficient. An autonomous system of equations is developed by defining normalized dimensionless variables. We find corresponding critical points for di.erent values of the parameters to investigate stability of the system. It is found that the presence of power-law model of bulk viscosity appears as an e.ective ingredient to enhance the stability of the respective universe model.
Superradiant Phenomena for Spinor Fields in Rotating Black Hole Geometry
Authors: Kenmoku Masakatsu , Cho Yongmin , Shigemoto Kazuyasu , Yoon Jong-Hyuk
Published: January 2018

We derive the results (i) the ortho-normal and completeness relations for normal modes and (ii) non-existence of zero mode for spinor fields in rotating black hole geometry. From these results, we show that superradiant phenomena for spinor fields should be type 2: positive momentum on the horizon (pH > 0) and negative frequency at infinity (ω < 0).
Dilatonic dyon black hole solutions in the model with two Abelian gauge fields
Authors: Abishev Medeu , Ivashchuk Dmitry , Boshkayev Kuantay , Malybayev Algys
Published: January 2018

Dilatonic black hole dyon-like solutions in the gravitational 4d model with a scalar field, two 2-forms, two dilatonic coupling constants λi ≠ 0, i = 1,2, obeying λ1 ≠ − λ2 and sign parameter ε = ±1 for scalar field kinetic term are considered. Here ε = −1 corresponds to ghost scalar field. These solutions are defined up to solutions of two master equations for two moduli functions, when λi2 ≠ 1/2 for ε = −1. A set of bounds on gravitational mass and scalar charge are presented by using a certain conjecture on parameters of solutions, when 1 + 2λi2ε > 0, i = 1, 2.
Speed control of switched reluctance motor using genetic algorithm and ant colony based on optimizing PID controller
Authors: El-Sayed Ahmed Ibrahim Hassan , Said Sayed Ahmed Mohamed , Mohamed Awad Khaled
Published: January 2018

Proportional-Integral-Derivative control is the most used kind of control which provides the simplest and most effective solution to different kinds of control engineering applications. But until now PID controller is poorly tuned in real life and online applications. While most of PID tuning is done manually. Switched reluctance motor (SRM) has highly nonlinear characteristics since the developed/produced torque of the motor has a nonlinear function on both phase current and rotor position. These nonlinearities of the SRM drives make the conventional PID (proportional + integral + Derivative) controller a poor choice for application where high dynamic performance is desired under all motor operating conditions. research paper comes up with two artificial and hybrid techniques involving Genetic Algorithm (GA) and Ant Colony Optimization (ACO). Those techniques where used to tune the PID parameters for the switched reluctance motor (SRM) and its performance were compared with the conventional method of “Ziegler Nichols. The results obtained reflects that, the use of those algorithms based controller improves the performance of the whole process in terms of a fast set point tracking and regulatory changes and also provides an optimum stability for the system itself with a minimum overshoot on the output signal.
Wavelet Co-movement Significance Testing with Respect to Gaussian White Noise Background
Authors: Poměnková Jitka , Klejmová Eva , Malach Tobiáš
Published: January 2018

The paper deals with significance testing of time series co-movement measured via wavelet analysis, namely via the wavelet cross-spectra. This technique is very popular for its better time resolution compare to other techniques. Such approach put in evidence the existence of both long-run and short-run co-movement. In order to have better predictive power it is suitable to support and validate obtained results via some testing approach. We investigate the test of wavelet power cross-spectrum with respect to the Gaussian white noise background with the use of the Bessel function. Our experiment is performed on real data, i.e. seasonally adjusted quarterly data of gross domestic product of the United Kingdom, Korea and G7 countries. To validate the test results we perform Monte Carlo simulation. We describe the advantages and disadvantages of both approaches and formulate recommendations for its using.
Analysis of Relationship Between Personality and Favorite Places with Poisson Regression Analysis
Authors: Yoon Song Ha , Baek Kang Hwa
Published: January 2018

A relationship between human personality and preferred locations have been a long conjecture for human mobility research. In this paper, we analyzed the relationship between personality and visiting place with Poisson Regression. Poisson Regression can analyze correlation between countable dependent variable and independent variable. For this analysis, 33 volunteers provided their personality data and 49 location categories data are used. Raw location data is preprocessed to be normalized into rates of visit and outlier data is prunned. For the regression analysis, independent variables are personality data and dependent variables are preprocessed location data. Several meaningful results are found. For example, persons with high tendency of frequent visiting to university laboratory has personality with high conscientiousness and low openness. As well, other meaningful location categories are presented in this paper.
CFD Analysis of 2D Unsteady Flow Past a Square Cylinder at Low Reynolds Numbers
Authors: Li Zhenquan , Wood Robert
Published: January 2018

A study of the behaviour of flow past a square cylinder for Reynolds numbers 10 and 20 is presented. Open source software Navier2d in Matlab is used in this study. The investigation starts from a uniform initial mesh and then refine the initial mesh using a mesh refinement method which was proposed based on both qualitative theory of differential equations and the finite volume method implemented in Navier2d. The horizontal and vertical velocity component profiles and pressures are shown on the once refined meshes. The comparisons between the profiles and pressures are conducted to show the variations from Reynolds number 10 to 20. The twice refined meshes are also presented and these refined meshes provide the information where the behaviour of flow is complex.
A new off-lattice HP model with side-chains for protein folding problem
Authors: Todorin Ivan , Yanev Nicola , Traykov Metodi , Yurukov Borislav
Published: January 2018

A HP like nonlinear programming model and a “brutforce” algorithm is proposed. The model takes into account highest degree of complexity – different size of radiuses of side-chains, mentioned below as radicals, and two stages of the algorithm, including random structure initially and subsequent purposeful folding process according to the physical forces and energies. The very preliminary computational runs favourably demonstrate the adequateness of the model and the efficiency of the algorithm.
Adaptive Collaborative Quantum-Inspired Evolutionary Algorithm for Global Numerical Functions
Authors: Liang Zhou , Ming Shao , Chengqian Ma
Published: January 2018

A novel adaptive collaborative quantum-inspired evolutionary algorithm (ACQEA) is proposed by combining the collaborative evolution and adaptive mutation mechanism together in this paper. In ACQEA, the whole population will be divided into multi sub-populations which can complete the evolution independently, and then the collaborative evolution mechanism is used to make these multi sub-populations full exchange their evolution information in operation process. In addition, the adaptive mutation and update strategies are implemented in order to give ACQEA the power to explore its search space on the basis of characteristic information of the elite individual and corresponding population diversity. Finally, the proposed ACQEA is compared with existing quantum evolution algorithm (QEA) in solving global numerical functions and the experiments results verify that the advantages of ACQEA on convergence rate and searching accuracy.
Statistical analysis of ambient air PM10 contami-nation during winter periods for Ruse region, Bulgaria.
Authors: Tsvetanova Irina , Zheleva Ivanka , Filipova Margarita , Stefanova Antoaneta
Published: January 2018

The sources of dust on the territory of Ruse region, Bulgaria are industry, transport and domestic heating by solid fuel. PM10 (particulate matter with a diameter between 2.5 and 10 μm) levels for Ruse mark a significant increase during the autumn-winter period compared to the levels during the spring-summer period [1]. Obviously there is a relationship between PM10 contamination levels and ambient air temperature. The lower the temperatures are, the higher the PM10 levels are. The biggest peak of PM10 levels for the autumn-winter period is usually observed in January months. It is in January that the number of days in which there is exceedance of the limit values of the PM10 levels is maximum observed. Also in January months the day and night temperatures are the lowest and usually they do not pass 0°C for many days of the month. To understand better this relationship we provide a statistical analysis of ambient air PM10 contamination during winter periods. Correlations between the measured PM10 values and the respective temperatures measured for January months for different years are presented. Descriptive statistics of PM10 and some atmospheric characteristics as well as linear regression analysis are calculated and commented in the paper.
Order parameter profiles in a system with Neumann – Neumann boundary conditions
Authors: Vassilev Vassil M. , Dantchev Daniel M. , Djondjorov Peter A.
Published: January 2018

In this article we consider a critical thermodynamic system with the shape of a thin film confined between two parallel planes. It is assumed that the state of the system at a given temperature and external ordering field is described by order-parameter profiles, which minimize the one-dimensional counterpart of the standard ϕ4 Ginzburg–Landau Hamiltonian and meet the so-called Neumann – Neumann boundary conditions. We give analytic representation of the extremals of this variational problem in terms ofWeierstrass elliptic functions. Then, depending on the temperature and ordering field we determine the minimizers and obtain the phase diagram in the temperature-field plane.
Evaluation by nanoindentation of technological products manufactured by pulse injection molding process
Authors: Natova Margarita , Ivanov Ivan , Cherneva Sabina , Datcheva Maria , Iankov Roumen
Published: January 2018

During conventional polymer injection molding, flow- and weld lines can arise at the molded parts caused by disturbed polymer melt flow when it crosses different parts of the equipment. Such processed plastic goods have discrete zones of inhomogeneities of very small dimensions. In order to stabilize the melt flow and to equalize dimensions of such defective products, an approach for pulse injection molding is applied during production of polymer packagings. Testing methods used for evaluation of macromechanical performance of processed polymer products are not readily applicable to estimate the changes in visual surface obtained during pulse injecting. To overcome this testing inconvenience the performance of processed packagings is evaluated by nanoindentation. Using this method, a quantitative assessment of the polymer properties is obtained from different parts of technological products.
A case study of the plasma in the magneto-sheath using the numerical magnetosheath-magnetosphere model and THEMIS measure-ments
Authors: Dobreva Polya , Nitcheva Olga , Kartalev Monio
Published: January 2018

This paper presents a case study of the plasma parameters in the magnetosheath, based on THEMIS measurements. As a theoretical tool we apply the self-consistent magnetosheath-magnetosphere model. A specific aspect of the model is that the positions of the bow shock and the magnetopause are self-consistently determined. In the magnetosheath the distribution of the velocity, density and temperature is calculated, based on the gas-dynamic theory. The magnetosphere module allows for the calculation of the magnetopause currents, confining the magnetic field into an arbitrary non-axisymmetric magnetopause. The variant of the Tsyganenko magnetic field model is applied as an internal magnetic field model. As solar wind monitor we use measurements from the WIND spacecraft. The results show that the model quite well reproduces the values of the ion density and velocity in the magnetosheath. The simlicity of the model allows calulations to be perforemed on a personal computer, which is one of the mean advantages of our model.
Wetting of doubly periodic rough surfaces in Wenzel’s regime
Authors: Iliev Stanimir , Pesheva Nina , Iliev Pavel
Published: January 2018

In this work we present preliminary results from our numerical study of the shapes of a liquid meniscus in contact with doubly sinusoidal rough surfaces in Wenzel’s wetting regime. Using the full capillary model we obtain the advancing and the receding equilibrium meniscus shapes for a broad interval of surface roughness factors. The contact angle hysteresis is obtained when the three-phase contact line is located on one row (block case) or several rows (kink case) of physical defects. We find that depending on the mutual disposition of the contact line and the lattice of periodic defects, different stick-slip behaviors of the contact line depinning mechanism appear, leading to different values of the contact angle hysteresis.
Numerical investigation of high temperature synthesis gas premixed combustion via ANSYS Fluent
Authors: Pashchenko Dmitry
Published: January 2018

A numerical model of the synthesis gas pre-mixed combustion is developed. The research was carried out via ANSYS Fluent software. Verification of the numerical results was carried out using experimental data. A visual comparison of the flame contours that obtained by the synthesis gas combustion for Re = 600; 800; 1000 was performed. A comparison of the wall temperature of the combustion chamber, obtained with the help of the developed model, with the results of a physical experiment was also presented. For all cases, good convergence of the results is observed. It is established that a change in the temperature of the syngas/air mixture at the inlet to the combustion chamber does not significantly affect the temperature of the combustion products due to the dissipation of the H2O and CO2 molecules. The obtained results are of practical importance for the design of heat engineering plants with thermochemical heat recovery.
Identification of the influence of the heating upon the heat transfer during pyrolysis process used for End-of-Life tires treatment
Authors: Zheleva Ivanka , Georgiev Ivan , Filipova Margaritka
Published: January 2018

End-of-Life tires (EOLT) are waste that does not practically decompose in nature and because of this their sound treatment is needed for environment protection. One of the possible methods for such a treatment is pyrolysis process. Globally, around 23% of all EOLT are processed through pyrolysis, whereas in the Republic of Bulgaria only 5% are processed by pyrolysis. This shows that for Bulgaria this method pyrolysis still has a good potential for development and further research. In our previous paper [1], an adequate mathematical model of non-stationary heat transfer during pyrolysis used for the treatment of end-of-life tires has been developed. A numerical algorithm has been also developed in MATLAB to solve the respective mathematical initial and boundary value problems. In this study on the base of the previously developed model we examine the temperature regimes in the pyrolysis station with three cameras and their strong dependence upon the characteristics of the initial heating. Results for the temperature fields, temperature isolines and gradients for different kind of initial heating of the process are presented and commented.
Human upper limb manipulator mass center motion and mass moments of inertia variation
Authors: Nikolova Gergana , Dantchev Daniel , Kazakoff Alexander
Published: January 2018

Motion control is complicated for people having traumas or neurological diseases. An underlying assumption in our work is that the motion of healthy people is optimal with respect to positioning accuracy, movement response, and energy expenditure. In this paper, a new approach for determination of the human upper limb mass-inertial characteristics is presented by using the 3D geometrical mathematical modeling analysis approach. Two examples will be given to illustrate the main features and advantages of the proposed design concepts. The objective of the work presented in this paper is a determination of the mass properties of a two joints human upper limb manipulator. Results are aimed to have application in an exoskeleton design, the design of manipulation system and external manipulation system, serving people with some motion difficulties, as well as in sport and rehabilitation.
CAD Design of Human Male Body for Mass–Inertial Characteristics Studies
Authors: Nikolova Gergana , Kotev Vladimir , Dantchev Daniel
Published: January 2018

The aim of the present research is to present a 16-segmental biomechanical model of the Bulgarian male to determine the mass-inertial characteristics of the body of the Bulgarian male based on parameters available in the literature and its 3D generation within SolidWorks software. The motivation of the research is to support mainly sport, rehabilitation, wearable robots and furniture design users. The proposed CAD model of the human body of men is verified against the analytical results from our previous investigation, as well as through comparison with data available in the provided references. In this paper we model two basic human body positions: standing position and sitting with thighs elevated. The comparison performed between our model results and data reported in literature gives us confidence that this model can be reliably used to calculate the mass-inertial characteristics of male body at any postures of the body that is of interest. Therefore, our model can be used to obtain data for positions which the human body has to take in everyday live, in sport, leisure, including space exploration, for investigating criminology cases – body fall, car crash, etc. The model is suitable for performing computer simulation in robotics, medicine, sport and other areas.
Investigation of the structure, phase composition and physical-mechanical characteristics of high-strength laminated materials which contain corrosion-resistant steels with high nitrogen content
Authors: Putilova Evgeniia , Gorkunov Eduard , Zadvorkin Sergey
Published: January 2018

In this work, we studied the structure, phase composition, mechanical and magnetic properties of structural steel clad with corrosion-resistant steels with varying degrees of austenite stability in order to determine the possibility of using magnetic methods for diagnostics the current state of such materials.
The interrelationships of magnetic and magneto acoustic-emission characteristics of heat-treated steels of various chemical composition
Authors: Kostin Vladimir , Serbin Evgeniy , Vasilenko Olga
Published: January 2018

The relationship between the amplitude of magnetoacoustic emission and the residual magnetic induction of the materials is shown. The dependence of magnetoacoustic emission (MAE) on the frequency of magnetization reversal of a group of steels of different chemical composition was investigated. In all the investigated cases, the MAE amplitude maximum corresponds to a field frequency of 3-5 Hz. The magnetic properties of two groups of steels subjected to various thermal treatments have been studied. It is shown that the residual magnetic induction of steels is a sufficiently universal parameter for controlling softening thermal treatments and that the amplitude of magnetoacoustic emission can be used as a testing parameter in scanning systems of structurescopy of ferromagnetic steels.
Methods for evaluation of mechanical stress condition of materials
Authors: Mirchev Yordan , Chukachev Pavel , Mihovski Mitko
Published: January 2018

Primary attention is given to the following methods: method by drilling cylindrical holes (drill method) and integrated ultrasonic method using volume (longitudinal and transverse), surface, and sub-surface waves. Drill method allows determination of residual mechanical stress in small depth of material surfaces, assessing type, size, and orientation of principal stresses. For the first time, parallel studies are carried out of mechanical stress in materials using the electroacoustic effect of volume, surface and sub-surface waves on the one hand, and effective mechanical stresses on the other. The experimental results present electroacoustic coefficients for different types of waves in the material of gas pipeline tube of 243 mm diameter and 14 mm thickness. These are used to evaluate mechanical stresses in pipelines, according to active GOST standards.
Protocole orthodontique et chirurgical : systématisation de la consultation d'annonce et apport de la médecine intégrative
Authors: Racy Emmanuel , Le Norcy Elvire
Published: January 2018

Introduction : La consultation d'annonce est une des périodes clefs dans la réalisation d'un protocole orthodontique et chirurgical. Cette consultation doit non seulement comprendre un diagnostic clinique esthétique et orthodontique, mais également une analyse fine de la psychologie du patient et de sa famille avant de proposer un plan de traitement. La médecine intégrative, évolution récente de la médecine dans le cadre de la relation médecin-malade, a démontré l'impact sur la guérison du relationnel soignant-soigné. Matériels et méthodes : Que ce soit pour l'observance du traitement, la gestion du stress pré- et post-opératoire ou plus simplement l'acceptation de la chirurgie dans le plan de traitement, la collecte d'informations préalables sur le psychisme du patient et son intégration à la décision finale font maintenant partie des bonnes pratiques. La tenue parfaite d'un dossier systématisé montrant que le patient a été considéré dans sa globalité, et non pas seulement par le diagnostic de sa dysmorphose, est un élément déterminant de la qualité de la prise en charge.
Impact of Surgical Margin in Skull Base Surgery for Head and Neck Sarcomas
Authors: Matsumoto Fumihiko , Miyakita Yasuji , Mori Taisuke , Shimoi Tatsunori , Murakami Naoya , Yoshida Akihiko , Arakawa Ayumu , Omura Go , Fukasawa Masahiko , Matsumoto Yoshifumi , Matsumura Satoko , Itami Jun , Narita Yoshitaka , Yoshimoto Seiichi , Kobayashi Kenya
Published: January 2018

Objective This study aimed to determine the adequate resection margin in skull base surgery for head and neck sarcoma.

Design We retrospectively reviewed 22 sarcomas with skull base invasion. Induction chemotherapy, followed by surgery and postoperative radiotherapy and adjuvant chemotherapy, was performed in 18 patients with chemosensitive sarcomas, and surgery with or without postoperative radiotherapy was performed in four patients with chemoresistant sarcomas. Radical resection was performed in patients with chemosensitive sarcomas with a poor response to induction chemotherapy and in patients with chemoresistant sarcomas. Conservative resection with close surgical margin was performed in patients with chemosensitive sarcomas with a good response to induction chemotherapy.

Setting and Participants This single-centered retrospective study included patients from the National Cancer Center Hospital, Japan.

Results The response to induction chemotherapy was significantly associated with the 3-year local control rate (LCR; good response versus poor response: 100% versus 63%, p = 0.048). Patients with a good response to chemotherapy had a favorable local prognosis even when the local therapy was conservative resection. In radical skull base surgery, patients whose surgical margins were classified as “wide margin positive” had significantly poorer 3-year LCR than did patients with “margin negative” or “micro margin positive” margins (25% versus 83%, p = 0.014).

Conclusion Conservative resection with close surgical margins might be acceptable for chemosensitive sarcomas with a good response to chemotherapy. Resection margin status was an important predictive factor for local recurrence after radical skull base surgery. Microscopic microresidual tumor might be controlled by postoperative treatment.
Molecular dynamics investigation of water-exchange reactions on lanthanide ions in water/1-ethyl-3-methylimidazolium trifluoromethylsufate ([EMIm][OTf])
Authors: Tu Yi-Jung , Lin Zhijin , Allen Matthew J. , Cisneros G. Andrés
Published: January 2018

We report a kinetic study of the water exchange on lanthanide ions in water/[1-ethyl-3-methylimidazolium][trifluoromethylsufate] (water/[EMIm][OTf]). The results from 17O-NMR measurements show that the water-exchange rates in water/[EMIm][OTf] increase with decreasing size of the lanthanide ions. This trend for water-exchange is similar to the previously reported trend in water/1-ethyl-3-methylimidazolium ethyl sulfate (water/[EMIm][EtSO4]) but opposite to that in water. To gain atomic-level insight into these water-exchange reactions, molecular dynamics simulations for lanthanide ions in water/[EMIm][OTf] have been performed using the atomic-multipole-optimized-energetics-for-biomolecular-application polarizable force field. Our molecular dynamics simulations reproduce the experimental water-exchange rates in terms of the trend and provide possible explanations for the observed experimental behavior. The smaller lanthanide ions in water/[EMIm][OTf] undergo faster water exchange because the smaller lanthanide ions coordinate to the first shell [OTf]− anions more tightly, resulting in a stronger screening effect for the second-shell water. The screening effect weakens the interaction of the lanthanide ions with the second-shell water molecules, facilitating the dissociation of water from the second-shell and subsequent association of water molecules from the outer solvation shells.
Description of nonideal Lorentz transformation for electromagnetic nulls
Authors: Yang Shu-Di , Wang Xiao-Gang
Published: January 2018

To identify characteristic topological features of the electromagnetic field in an arbitrary reference frame, Lorentz transformation properties of an electromagnetic field near a null point are explored under certain constraints, in different nonideal magnetohydrodynamics (MHD) situations for linear nulls, showing violations of topology accordingly. It is shown that Newcomb's condition for conservation of covariant magnetic surfaces does not necessarily mean conservation of field line topology under Lorentz transformation. Characterizations of the violation of magnetic topology under Lorentz transformation are given. A method describing local magnetic null webs by combination of the first and second order Taylor expansions is also proposed, whose transformation properties with possible nonideal influences are discussed in the frame of resistive MHD. These results are important for establishing a reasonable range of the fieldline picture and thus the dynamical analysis based on magnetic fieldlines.
On the possibility of superluminal energy propagation in a hyperbolic metamaterial of metal-dielectric layers
Authors: Luan Pi-Gang , Wu Jie-Luen
Published: January 2018

The energy propagation of electromagnetic fields in the effective medium of a one-dimensional photonic crystal consisting of dielectric and metallic layers is investigated. We show that the medium behaves like Drude and Lorentz medium, respectively, when the electric field is parallel and perpendicular to the layers. For arbitrary time-varying electromagnetic fields in this medium, the energy density formula is derived. We prove rigorously that the group velocity of any propagating mode obeying the hyperbolic dispersion must be slower than the speed of light in vacuum, taking into account the frequency dependence of the permittivity tensor. That is, it is not possible to have superluminal propagation in this dispersive hyperbolic medium consisting of real dielectric and metallic material layers. The propagation velocity of a wave packet is also studied numerically. This packet velocity is very close to the velocity of the propagating mode having the central frequency and central wave vector of the wave packet. When the frequency spread of the wave packet is not narrow enough, small discrepancy between these two velocities manifests, which is caused by the non-penetration effect of the evanescent modes. This work reveals that no superluminal phenomenon can happen in a dispersive anisotropic metamaterial medium made of real materials.
Molecular dynamics based enhanced sampling of collective variables with very large time steps
Authors: Chen Pei-Yang , Tuckerman Mark E.
Published: January 2018

Enhanced sampling techniques that target a set of collective variables and that use molecular dynamics as the driving engine have seen widespread application in the computational molecular sciences as a means to explore the free-energy landscapes of complex systems. The use of molecular dynamics as the fundamental driver of the sampling requires the introduction of a time step whose magnitude is limited by the fastest motions in a system. While standard multiple time-stepping methods allow larger time steps to be employed for the slower and computationally more expensive forces, the maximum achievable increase in time step is limited by resonance phenomena, which inextricably couple fast and slow motions. Recently, we introduced deterministic and stochastic resonance-free multiple time step algorithms for molecular dynamics that solve this resonance problem and allow ten- to twenty-fold gains in the large time step compared to standard multiple time step algorithms [P. Minary et al., Phys. Rev. Lett. 93, 150201 (2004); B. Leimkuhler et al., Mol. Phys. 111, 3579–3594 (2013)]. These methods are based on the imposition of isokinetic constraints that couple the physical system to Nosé-Hoover chains or Nosé-Hoover Langevin schemes. In this paper, we show how to adapt these methods for collective variable-based enhanced sampling techniques, specifically adiabatic free-energy dynamics/temperature-accelerated molecular dynamics, unified free-energy dynamics, and by extension, metadynamics, thus allowing simulations employing these methods to employ similarly very large time steps. The combination of resonance-free multiple time step integrators with free-energy-based enhanced sampling significantly improves the efficiency of conformational exploration.
Large hh-lh splitting energy for InAs/AlSb/GaSb based N-structure photodetectors
Authors: Akel K. , Hostut M. , Tansel T. , Ergun Y.
Published: January 2018

We investigate the band properties of InAs/AlSb/GaSb (N-structure) and InAs/GaSb material based type II superlattice (T2SL) photodedectors. The superlattice empirical pseudopotential method is used to define band-structures such as the bandgap and heavy hole-light hole (hh-lh) splitting energies in the mid-wavelength infrared range (MWIR) and long wavelength range (LWIR). The calculations are carried out on the variation of AlSb/GaSb layer thickness for (InAs)10.5/(AlSb)x/(GaSb)9-x and the variation of InAs layer thickness for (InAs)x/(AlSb)3/(GaSb)6 T2SL structures at 77 K. For the same bandgap energy of 229 meV (5.4 μm in wavelength), hh-lh splitting energy is calculated as 194 meV for the (InAs)7.5/(AlSb)3/(GaSb)6 structure compared to the (InAs)10.5/(GaSb)9 structure with hh-lh splitting energy of 91 meV within the MWIR. Long wavelength performance of InAs/AlSb/GaSb structure shows superior electronic properties over the standard InAs/GaSb T2SL structure with larger hh-lh splitting energy which is larger than the bandgap energy. The best result is obtained for (InAs)17/(AlSb)3/(GaSb)6 with the minimum bandgap of 128 meV with hh-lh splitting energy of 194 meV, which is important for suppressing the Auger recombination process. These values are very promising for a photodetector design in both MWIR and LWIR in high temperature applications.
Graphene-like layers as promising chemiresistive sensing material for detection of alcohols at low concentration
Authors: Gargiulo Valentina , Alfano Brigida , Di Capua Roberto , Alfé Michela , Vorokhta Mykhailo , Polichetti Tiziana , Massera Ettore , Miglietta Maria Lucia , Schiattarella Chiara , Di Francia Girolamo
Published: January 2018

In the manifold of materials for Volatile Organic Compound (VOC) sensing, graphene related materials (GRMs) gain special attention thanks to their versatility and overall chemico-physical tunability as a function of specific applications. In this work, the sensing performances of graphene-like (GL) layers, a new material belonging to the GRM family, are tested against ethanol and n-butanol. Two typologies of GL samples were produced by employing two different approaches and tested in view of their application as VOC sensors. The experiments were performed under atmospheric pressure, in dry air, and at room temperature and demonstrated that the sensing capabilities are related to the film surface features. The results indicated that GL films are promising candidates for the detection of low concentrations of VOCs at room temperature. The present investigation thus paves the way for VOC sensing optimization using cost-effective and easily scalable materials.
Tensor-decomposed vibrational coupled-cluster theory: Enabling large-scale, highly accurate vibrational-structure calculations
Authors: Madsen Niels Kristian , Godtliebsen Ian H. , Losilla Sergio A. , Christiansen Ove
Published: January 2018

A new implementation of vibrational coupled-cluster (VCC) theory is presented, where all amplitude tensors are represented in the canonical polyadic (CP) format. The CP-VCC algorithm solves the non-linear VCC equations without ever constructing the amplitudes or error vectors in full dimension but still formally includes the full parameter space of the VCC[n] model in question resulting in the same vibrational energies as the conventional method. In a previous publication, we have described the non-linear-equation solver for CP-VCC calculations. In this work, we discuss the general algorithm for evaluating VCC error vectors in CP format including the rank-reduction methods used during the summation of the many terms in the VCC amplitude equations. Benchmark calculations for studying the computational scaling and memory usage of the CP-VCC algorithm are performed on a set of molecules including thiadiazole and an array of polycyclic aromatic hydrocarbons. The results show that the reduced scaling and memory requirements of the CP-VCC algorithm allows for performing high-order VCC calculations on systems with up to 66 vibrational modes (anthracene), which indeed are not possible using the conventional VCC method. This paves the way for obtaining highly accurate vibrational spectra and properties of larger molecules.
Depletion-mode quantum dots in intrinsic silicon
Authors: Amitonov Sergey V. , Spruijtenburg Paul C. , Vervoort Max W. S. , van der Wiel Wilfred G. , Zwanenburg Floris A.
Published: January 2018

We report the fabrication and electrical characterization of depletion-mode quantum dots in a two-dimensional hole gas (2DHG) in intrinsic silicon. We use fixed charge in a SiO2/Al2O3 dielectric stack to induce a 2DHG at the Si/SiO2 interface. Fabrication of the gate structures is accomplished with a single layer metallization process. Transport spectroscopy reveals regular Coulomb oscillations with charging energies of 10–15 meV and 3–5 meV for the few- and many-hole regimes, respectively. This depletion-mode design avoids complex multilayer architectures requiring precision alignment and allows us to adopt directly best practices already developed for depletion dots in other material systems. We also demonstrate a method to deactivate fixed charge in the SiO2/Al2O3 dielectric stack using deep ultraviolet light, which may become an important procedure to avoid unwanted 2DHG build-up in Si MOS quantum bits.