bluuebunny/crossref_metadata_2025 huggingface dataset:
A GNS construction of three-dimensional abelian Dijkgraaf–Witten theories
Authors: Müller Lukas , Schweigert Christoph
Published: November 2017

We give a detailed account of the so-called “universal construction” that aims to extend invariants of closed manifolds, possibly with additional structure, to topological field theories and show that it amounts to a generalization of the GNS construction. We apply this construction to an invariant defined in terms of the groupoid cardinality of groupoids of bundles to recover Dijkgraaf–Witten theories, including the vector spaces obtained as a linearization of spaces of principal bundles.
Estimates for eigenvalues of ℒr operator on self-shrinkers
Authors: Huang Guangyue , Qi Xuerong , Li Hongjuan
Published: November 2017

Let [Formula: see text] be an [Formula: see text]-dimensional compact self-shrinker in [Formula: see text] with smooth boundary [Formula: see text]. In this paper, we study eigenvalues of the operator [Formula: see text] on [Formula: see text], where [Formula: see text] is defined by [Formula: see text] with [Formula: see text] denoting a positive definite (0,2)-tensor field on [Formula: see text]. We obtain “universal” inequalities for eigenvalues of the operator [Formula: see text]. These inequalities generalize the result of Cheng and Peng in [Estimates for eigenvalues of [Formula: see text] operator on self-shrinkers, Commun. Contemp. Math. 15(6) (2013), Article ID:1350011, 23 pp.]. Furthermore, we also consider the case that equalities occur.
Stability conditions and related filtrations for (G,h)-constellations
Authors: Terpereau Ronan , Zamora Alfonso
Published: November 2017

Given an infinite reductive algebraic group [Formula: see text], we consider [Formula: see text]-equivariant coherent sheaves with prescribed multiplicities, called [Formula: see text]-constellations, for which two stability notions arise. The first one is analogous to the [Formula: see text]-stability defined for quiver representations by King [Moduli of representations of finite-dimensional algebras, Quart. J. Math. Oxford Ser.[Formula: see text]2) 45(180) (1994) 515–530] and for [Formula: see text]-constellations by Craw and Ishii [Flops of [Formula: see text]-Hilb and equivalences of derived categories by variation of GIT quotient, Duke Math. J. 124(2) (2004) 259–307], but depending on infinitely many parameters. The second one comes from Geometric Invariant Theory in the construction of a moduli space for [Formula: see text]-constellations, and depends on some finite subset [Formula: see text] of the isomorphy classes of irreducible representations of [Formula: see text]. We show that these two stability notions do not coincide, answering negatively a question raised in [Becker and Terpereau, Moduli spaces of [Formula: see text]-constellations, Transform. Groups 20(2) (2015) 335–366]. Also, we construct Harder–Narasimhan filtrations for [Formula: see text]-constellations with respect to both stability notions (namely, the [Formula: see text]-HN and [Formula: see text]-HN filtrations). Even though these filtrations do not coincide in general, we prove that they are strongly related: the [Formula: see text]-HN filtration is a subfiltration of the [Formula: see text]-HN filtration, and the polygons of the [Formula: see text]-HN filtrations converge to the polygon of the [Formula: see text]-HN filtration when [Formula: see text] grows.
Paradox of integration — mean field approach
Authors: Kułakowski Krzysztof , Gronek Piotr , Borzì Alfio
Published: November 2017

Recently, a computational model has been proposed of the social integration, as described in sociological terms by Blau. In this model, actors praise or critique each other, and these actions influence their social status and raise negative or positive emotions. The role of a self-deprecating strategy of actors with high social status has also been discussed there. Here, we develop a mean field approach, where the active and passive roles (praising and being praised, etc.) are decoupled. The phase transition from friendly to hostile emotions has been reproduced, similarly to the previously applied purely computational approach. For both phases, we investigate the time dependence of the distribution of social status. There we observe a diffusive spread, which — after some transient time — appears to be limited from below or from above, depending on the phase. As a consequence, the mean status flows.
Curcumin Decreases Hyperphosphorylation of Tau by Down-Regulating Caveolin-1/GSK-3β in N2a/APP695swe Cells and APP/PS1 Double Transgenic Alzheimer’s Disease Mice
Authors: Sun Jieyun , Zhang Xiong , Wang Chen , Teng Zhipeng , Li Yu
Published: November 2017

Caveolin-1, the marker protein of membranal caveolae, is not only involved in cholesterol regulation, but also participates in the cleavage of amyloid [Formula: see text]-protein precursor (APP) and the generation of [Formula: see text]-amyloid peptide. It has been reported to be tightly related with Tau. In our previous studies, curcumin has been confirmed to play a neuroprotective role in Alzheimer’s disease (AD), but its effects on Caveolin-1, Tau and their correlation, and the mechanism is still unknown. As such, in the present study, N2a/WT cells, N2a/APP695swe cell and six-month-old APP/PS1 double transgenic mice were enrolled. After curcumin treatment, the expression of Caveolin-1, Tau and their relationship was detected, and the potential mechanisms were explored. The results showed that in the N2a/APP695swe cells, curcumin not only decreased the number of caveolae, but also made their membrane to be thinner; and curcumin could decreased the expression of phosphorylated Tau (P-Tau(ser404)/Tau) and Caveolin-1 ([Formula: see text]), but the expression of phosphorylated GSK-3[Formula: see text] (P-GSK-3[Formula: see text]/GSK-3[Formula: see text] was increased ([Formula: see text]). In APP/PS1 transgenic mice, the same results were observed. Taken together, our data suggest that curcumin may play an important role in AD via reducing Caveolin-1, inactivating GSK-3[Formula: see text] and inhibiting the abnormal excessive phosphorylation of Tau, which will provide a new theory for AD treatment with curcumin.
Minimal presentations of shifted numerical monoids
Authors: Conaway Rebecca , Gotti Felix , Horton Jesse , O’Neill Christopher , Pelayo Roberto , Pracht Mesa , Wissman Brian
Published: November 2017

A numerical monoid is an additive submonoid of the non-negative integers. Given a numerical monoid [Formula: see text], consider the family of “shifted” monoids [Formula: see text] obtained by adding [Formula: see text] to each generator of [Formula: see text]. In this paper, we examine minimal relations among the generators of [Formula: see text] when [Formula: see text] is sufficiently large, culminating in a description that is periodic in the shift parameter [Formula: see text]. We explore several applications to computation and factorization theory, and improve a recent result of Thanh Vu from combinatorial commutative algebra.
Knot adjacency from a surgical view of Alexander invariants
Authors: Nakanishi Yasutaka , Shimoda Masahiro
Published: November 2017

For two knots [Formula: see text] and [Formula: see text], [Formula: see text] is said to be [Formula: see text]-adjacent to [Formula: see text], if [Formula: see text] admits a knot diagram containing [Formula: see text] crossings such that crossing changes at any non-empty subset of them yield a knot diagram of [Formula: see text]. Using a surgical view of Alexander invariants, we will characterize the Alexander polynomials of knots which are [Formula: see text]-adjacent to the trivial knot.
EFFECT OF HEAT TREATMENT ON MICROSTRUCTURE AND CORROSION RESISTANCE OF Ni-B-W-Mo COATING DEPOSITED BY ELECTROLESS METHOD
Authors: MUKHOPADHYAY ARKADEB , BARMAN TAPAN KUMAR , SAHOO PRASANTA
Published: November 2017

The present work reports the deposition of a quaternary Ni-B-W-Mo coating on AISI 1040 medium carbon steel and its characterization. Quaternary deposits are obtained by suitably modifying existing electroless Ni-B bath. Composition of the as-deposited coating is analyzed by energy dispersive X-ray spectroscopy. The structural aspects of the as-deposited and coatings heat treated at 300[Formula: see text]C, 350[Formula: see text]C, 400[Formula: see text]C, 450[Formula: see text]C and 500[Formula: see text]C are determined using X-ray diffraction technique. Surface of the as-deposited and heat-treated coatings is examined using a scanning electron microscope. Very high W deposition could be observed when sodium molybdate is present in the borohydride-based bath along with sodium tungstate. The coatings in their as-deposited condition are amorphous while crystallization takes place on heat treatment. A nodulated surface morphology of the deposits is also observed. Vickers’ microhardness and crystallite size measurement reveal inclusion of W and Mo results in enhanced thermal stability of the coatings. Solid solution strengthening of the electroless coatings by W and Mo is also observed. The applicability of kinetic strength theory to the hardening of the coatings on heat treatment is also investigated. Corrosion resistance of Ni-B-W-Mo coatings and effect of heat treatment on the same are also determined by electrochemical techniques.
MORPHOLOGICAL AND MICROSTRUCTURAL CHARACTERISTICS OF HA COMPOSITE FILMS DEPOSITED BY PULSED LASER
Authors: ZHANG W. L. , SHI H. , WANG D. G. , CHEN C. Z.
Published: November 2017

The influence of oxygen atmosphere and substrate temperature on morphology and microstructure of the hydroxyapatite (HA) composite films prepared by pulsed laser deposition (PLD) was studied. According to the results of X-ray diffraction (XRD), scanning electron microscope (SEM), and Fourier transform infrared spectroscopy (FTIR), it was found that the phase compositions and the crystallinity of HA were affected by the oxygen pressure and substrate temperature. High oxygen pressure can increase the crystallinity of HA, and make random oriented HA gradually transform into [Formula: see text]-axis orientation, and decrease the Ca/P atomic ratio of the film. High substrate temperature can increase the crystallinity of films and the degree of c-axis orientation of HA, but increase the Ca/P atomic ratio slightly. Changes of oxygen pressure or substrate temperature have little influence on the surface morphology and thickness of film. Valuable HA composite film could be obtained at 600[Formula: see text]C under 5[Formula: see text]Pa O2atmosphere.
EFFECT OF POWER AND HYDROTHERMAL HEAT TREATMENT ON RF SPUTTERED COPPER OXIDE THIN FILMS
Authors: KAUR JASMEET , SINGH R.
Published: November 2017

Nano-crystalline copper oxide films were deposited on quartz substrates by RF-magnetron sputtering in argon gas environment. The XRD patterns show Cu4O3 phase for films deposited at 50 and 60[Formula: see text]W of RF power. The film deposited at 70[Formula: see text]W shows existence of Cu4O3 and CuO phases, whereas film deposited at 100[Formula: see text]W of RF power consists of only CuO phase. Raman spectra and transmission electron microscopy (TEM) also confirm these results. Field emission scanning electron microscopy (FESEM) shows morphological changes in the film as a function of RF power. The optical band gap estimated from the transmission spectra of the films are 2.3 and 1.7[Formula: see text]eV for Cu4O3 and CuO phase, respectively. The hydrothermal heat treatment of the film leads to transformation of Cu4O3 to CuO phase in the film.
EFFECT OF LASER QUENCHING ON MICROSTRUCTURE AND PROPERTIES OF THE SURFACE OF TRACK MATERIALS
Authors: PING XUE-LONG , FU HAN-GUANG , WANG KAI-MING , SUN SHU-TING , JU JIANG , LIN JIAN , YI DA-WEI , XING ZHEN-GUO , LEI YONG-PING
Published: November 2017

With the rapid development of rail transit, the wear problem of track has become a serious challenge. Laser quenching is a new surface modification process, and it is expected to improve the service life of the track. Laser quenching was carried on the surface of rails by using 6[Formula: see text]kW fiber laser. The microstructure, hardness, wear resistance, and contact fatigue resistance (CFR) of the phase transformation hardening layer were studied by optical microscope (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD), microhardness tester, and wear tester. The results show that the microstructure of the hardened layer is composed of fine martensite and a small fraction of retained austenite. The microstructure of substrate is pearlite and ferrite. The hardness of rails quenched by the laser increased nearly two times than that of the un-treated track materials. When the laser power is 1000[Formula: see text]W, the depth of hardened layer reaches 0.8[Formula: see text]mm, and the wear resistance of hardened layer increases 167% than that of the substrate. The number, length, and depth of fatigue cracks decreased on the cross-section of worn rails after laser quenching, which indicates that laser quenching can improve the CFR of rails.
MECHANICAL PROPERTIES OF THE Fe-Al-Nb COATING BY DOUBLE GLOW PLASMA SURFACE METALLURGY
Authors: ZHANG ZELEI , YAO ZHENGJUN
Published: November 2017

The Q235 steel was covered by Fe–Al–Nb alloyed coating to improve the mechanical properties of the Q235 steel. This double glow plasma surface metallurgy (DGPSM) surface modification technique was carried out at 1023[Formula: see text]K and pressure of 38[Formula: see text]Pa for 4.5[Formula: see text]h. The surface morphology represented the typical Volmer–Weber mode, an island structure which was accumulated by numerous small particles, and most of the angles formed between three islands were about 120[Formula: see text] where there was no appreciable defect. Meanwhile, in the cross-sectional morphology of the Fe–Al–Nb coating, there was a deposition layer, a diffusion layer and two transition regions between the different adjacent interfaces, and the coating approximate 17[Formula: see text][Formula: see text]m was found to be metallurgically adhered to the Q235 steel. The basic mechanical properties of the Fe–Al–Nb coating and Q235 steel including the hardness, elastic modulus and friction performance were measured and compared. The results showed that the formation of Fe3Al, FeAl, and Fe2Nb intermetallic compounds and Nb carbides in the coating can enhance the mechanical properties of the treated sample. The nanoindentation tests indicated that the hardness and elastic modulus of Fe–Al–Nb coating were 8.08[Formula: see text]GPa and 260.03[Formula: see text]GPa which were much higher than Q235 steel. The sliding friction tests showed that Fe–Al–Nb coating significantly improved the friction performance of Q235 steel at the speed of 300, 600 and 900[Formula: see text]rpm with load 320[Formula: see text]g for 15[Formula: see text]min.
A STUDY ON SCAN SPEED RELATIONSHIP WITH MICROSTRUCTURAL EVOLUTION, PHASE COMPOSITION AND MICROHARDNESS OF Ni-CONTAINING INTERMETALLIC COATINGS ON Ti–6Al–4V USING LASER CLADDING TECHNIQUE
Authors: ADESINA O. S. , POPOOLA A. P. I. , PITYANA S. L. , OLORUNTOBA D. T.
Published: November 2017

Titanium alloys have been used for variety of engineering applications but their relatively low hardness and low thermal conductivity are shortcomings that have reduced their potential use. In this work, attempts have been made to study the effects of laser scanning speed and admixed fraction of reinforced Ni–Co powders on clad layer formation and its corresponding properties on Ti–6Al–4V. Laser power of 750[Formula: see text]W, beam size of 3[Formula: see text]mm with argon shield gas flow rate of 1.2[Formula: see text]L/min was made constant, while the powders were premixed and deposited on Ti–6Al–4V with varying compositions at different scanning speeds of 0.6 and 1.2[Formula: see text]m/min. The microstructural analysis, phase constituents and hardness properties of Ni–Co intermetallics reinforced clads were also examined. The morphology of the resultant coatings was analyzed using X-ray diffractometry (XRD) and scanning electron microscopy (SEM) equipped with energy dispersive spectrometry (EDS). The research results showed that laser cladding coatings displayed enhanced properties such as fine microstructure and good metallurgical bonding with the substrate containing minimal pores with respect to the substrate. Furthermore, the microstructure revealed the formation of various fractions of interdendritic compounds/intermetallics dispersed within the coating matrix which could be responsible for the increased hardness obtained. The average hardness of the coating was about 856[Formula: see text]HV [Formula: see text], which was about 2.5 times that of the substrate.
Lowest degree invariant second-order PDEs over rational homogeneous contact manifolds
Authors: Alekseevsky Dmitri V. , Gutt Jan , Manno Gianni , Moreno Giovanni
Published: November 2017

For each simple Lie algebra [Formula: see text] (excluding, for trivial reasons, type [Formula: see text]), we find the lowest possible degree of an invariant second-order PDE over the adjoint variety in [Formula: see text], a homogeneous contact manifold. Here a PDE [Formula: see text] has degree [Formula: see text] if [Formula: see text] is a polynomial of degree [Formula: see text] in the minors of [Formula: see text], with coefficient functions of the contact coordinate [Formula: see text], [Formula: see text], [Formula: see text] (e.g., Monge–Ampère equations have degree 1). For [Formula: see text] of type [Formula: see text] or [Formula: see text], we show that this gives all invariant second-order PDEs. For [Formula: see text] of types [Formula: see text] and [Formula: see text], we provide an explicit formula for the lowest-degree invariant second-order PDEs. For [Formula: see text] of types [Formula: see text] and [Formula: see text], we prove uniqueness of the lowest-degree invariant second-order PDE; we also conjecture that uniqueness holds in type [Formula: see text].
High-dimensional limit theorems for random vectors in ℓpn-balls
Authors: Kabluchko Zakhar , Prochno Joscha , Thäle Christoph
Published: November 2017

In this paper, we prove a multivariate central limit theorem for [Formula: see text]-norms of high-dimensional random vectors that are chosen uniformly at random in an [Formula: see text]-ball. As a consequence, we provide several applications on the intersections of [Formula: see text]-balls in the flavor of Schechtman and Schmuckenschläger and obtain a central limit theorem for the length of a projection of an [Formula: see text]-ball onto a line spanned by a random direction [Formula: see text]. The latter generalizes results obtained for the cube by Paouris, Pivovarov and Zinn and by Kabluchko, Litvak and Zaporozhets. Moreover, we complement our central limit theorems by providing a complete description of the large deviation behavior, which covers fluctuations far beyond the Gaussian scale. In the regime [Formula: see text] this displays in speed and rate function deviations of the [Formula: see text]-norm on an [Formula: see text]-ball obtained by Schechtman and Zinn, but we obtain explicit constants.
Cycle characterization of the Aubry set for weakly coupled Hamilton–Jacobi systems
Authors: Ibrahim H. , Siconolfi A. , Zabad S.
Published: November 2017

We study a class of weakly coupled systems of Hamilton–Jacobi equations using the random frame introduced in [H. Mitake, A. Siconolfi, H. V. Tran and N. Yamada, A Lagrangian approach to weakly coupled Hamilton–Jacobi systems, SIAM J. Math. Anal. 48(2) (2016) 821–846; doi: https://doi.org/10.1137/15M1010841 ]. We provide a cycle condition characterizing the points of Aubry set. This generalizes a property already known in the scalar case.
Profile of solutions for nonlocal equations with critical and supercritical nonlinearities
Authors: Bhakta Mousomi , Mukherjee Debangana , Santra Sanjiban
Published: November 2017

We study the fractional Laplacian problem [Formula: see text] where [Formula: see text], [Formula: see text] and [Formula: see text] is a parameter. Here, [Formula: see text] is a bounded star-shaped domain with smooth boundary and [Formula: see text]. We establish existence of a variational positive solution [Formula: see text] and characterize the asymptotic behavior of [Formula: see text] as [Formula: see text]. When [Formula: see text], we describe how the solution [Formula: see text] blows up at an interior point of [Formula: see text]. Furthermore, we prove the local uniqueness of solution of the above problem when [Formula: see text] is a convex symmetric domain of [Formula: see text] with [Formula: see text] and [Formula: see text].
INNOVATIONS IN FINANCIAL INCLUSION OF THE URBAN POOR: A MODEL OF RAHAT CREDIT COOPERATIVE SOCIETY, INDIA
Authors: KULKARNI ANJALI
Published: November 2017

Most of the Asian countries face challenge of poverty which is linked with unemployment. Lack of assets and income make poor unable to invest for self employment or for knowledge /skill development leading to employment. Access to financial services may help people to come out of poverty through variety of ways like availing credit, insurance and saving facilities. In India, in spite of several initiatives for financial inclusion, field level data shows that by merely opening bank account the access to credit may not be there and financial inclusion in true sense may not happen. The microfinance movement had regional success in India. There are almost 35% urban poor in India indicating the need of innovations in financial services for them.

“Rahat Urban Credit Cooperative Society” was a initiative in 2008 of few persons belonging to Islam religion and believing on the teachings of Quran that the interest should not be taken. Though inspired by a particular religion the services are extended to all community groups. In today’s context when different religions are discussed for using the religious values/teachings negatively, Rahat will be a unique example how religious teachings can be utilized positively for society’s benefits. Since 2011, besides usual financial products, it gives interest free and collateral free loans for urban poor for self employment and for consumption purposes.

The case study focuses on understanding the community based business model and its impact on urban poor in terms of their financial needs by analyzing the financial performance. The study explores how 98% recovery rate for loans is there and how depositors are attracted for interest free product. It also tries to understand the use of social capital in provision of financial services for urban poor having inability to give collateral.

“Rahat” means relief. The present paper l brings out a Rahat model of financial services and inclusion of urban poor and try to understand how it has brought the relief in urban poor lives.
SOCIAL RETURN ON INVESTMENT FOR COMMUNITY-BASED ENTERPRISE IN SURABAYA CITY
Authors: PRATONO ALUISIUS HERY , SUYANTO  , MARCIANO DEDDY , ZURBRÜGG CHRISTIAN
Published: November 2017

This study aims to examine the social impact of a community-based enterprise model in Surabaya City. The analysis focuses on grass-root communities and highlights some technical challenges in order to develop a meta-theory with the intention of examining the underlying assumptions of the social return on investment. The social impact analysis is based on a social return on investment (SROI) approach, which involves community participation through focus group discussions. To avoid complexity, this study focuses on one year’s activities, which attributed monetary values to the social impact. It is argued in this study that the green and clean activities provide a return of 1.23 on the investment. This result demonstrates how the community-based social enterprise is feasible in achieving appropriate support. First, this study focuses on the community perspective during the observed time. The communities may experience different levels of capability and resources that contribute to the achievement of the programme. Secondly, there is a lack of literature that could provide financial analysis and there is no common accepted method for measuring the value of the social benefits. Beyond the SROI computation, this study highlights some technical challenges and misconceptions involved in measuring the social return on investment (SROI). Although there is considerable information available about the conceptual framework of SROI, there is great variability in how SROI is applied across interventions. This makes robust and consistent comparisons across social ventures difficult, while rendering the validity of SROI measures vulnerable to being contested.
Calculation of anharmonic effect on the dissociation of ethylene glycol
Authors: Li Qian , Yao Li , Lin S. H.
Published: November 2017

The unimolecular dissociation rate constants of ethylene glycol were examined using the MP2/6-311[Formula: see text]G(d,p) method based on the Rice–Ramsperger–Kassel–Marcus (RRKM) theory. The effect of anharmonicity on the dissociation rate constants was evaluated at 500–4000[Formula: see text]K temperatures of the canonical system and 25,182–50,235[Formula: see text]cm[Formula: see text] total energies of the microcanonical system. The comparison of the results showed that the H2O elimination reaction played a critical role in the decomposition processes of ethylene glycol. The results of the rate constant calculations indicated that the H2O elimination reaction dominated at low temperatures, whereas the direct C–C bond dissociation reaction (CH2OHCH2OH [Formula: see text] CH2OH[Formula: see text][Formula: see text][Formula: see text]CH2OH) dominated at high temperatures. For channel 1, CH2OH[Formula: see text][Formula: see text][Formula: see text]CH2OH, the anharmonic effect of the canonical system was not observed, while it became more obvious with the increasing total energies in the microcanonical system. For channels 2–5, CH3CHO[Formula: see text][Formula: see text][Formula: see text]H2O, CH2CHOH[Formula: see text][Formula: see text][Formula: see text]H2O, CH3OH[Formula: see text][Formula: see text][Formula: see text]CHOH, and CH2OHCHO[Formula: see text][Formula: see text][Formula: see text]H2, the anharmonic effect of canonical and microcanonical systems became more obvious with increasing temperatures and total energies. The comparison showed that, for channels 1 and 4, C–C bond dissociation and the anharmonic effect of the microcanonical system were more evident, whereas the anharmonic effect of the canonical system was more predominant for channels 2 (CH3CHO[Formula: see text][Formula: see text][Formula: see text]H2O), 3 (CH2CHOH[Formula: see text][Formula: see text][Formula: see text]H2O), and 5 (CH2OHCHO[Formula: see text][Formula: see text][Formula: see text]H2).
Noether symmetry of Palatini F(ℜ) gravity
Authors: Sk Nayem
Published: November 2017

In metric formalism, Noether symmetry of [Formula: see text] theory of gravity in vacuum and in the presence of pressureless dust yields [Formula: see text] along with the conserved current [Formula: see text] in Robertson–Walker metric and nothing else. However, Roshan and Shojai have claimed in [Palatini [Formula: see text] gravity and Noether symmetry, Phys. Lett. B 668 (2008) 238–240] that Noether symmetry in the context of Palatini [Formula: see text] theory of gravity admits [Formula: see text], (where [Formula: see text] is arbitrary) in matter domain era in Friedmann–Robertson–Walker universe. But, it has been shown that the conserved current obtained under the process does not satisfy the field equations in general. Here, it is shown that Noether Symmetry admits [Formula: see text] along with a conserved current [Formula: see text] in Palatini gravity. Thus, their claim is not right.
A path planning method for robot end effector motion using the curvature theory of the ruled surfaces
Authors: Güler Fatma , Kasap Emin
Published: November 2017

Using the curvature theory for the ruled surfaces a technique for robot trajectory planning is presented. This technique ensures the calculation of robot’s next path. The positional variation of the Tool Center Point (TCP), linear velocity, angular velocity are required in the work area of the robot. In some circumstances, it may not be physically achievable and a re-computation of the robot trajectory might be necessary. This technique is suitable for re-computation of the robot trajectory. We obtain different robot trajectories which change depending on the darboux angle function and define trajectory ruled surface family with a common trajectory curve with the rotation trihedron. Also, the motion of robot end effector is illustrated with examples.
Dirac and Klein–Gordon–Fock equations in Grumiller’s spacetime
Authors: Al-Badawi A. , sakalli I.
Published: November 2017

We study the Dirac and the chargeless Klein–Gordon–Fock equations in the geometry of Grumiller’s spacetime that describes a model for gravity of a central object at large distances. The Dirac equation is separated into radial and angular equations by adopting the Newman–Penrose formalism. The angular part of the both wave equations are analytically solved. For the radial equations, we managed to reduce them to one dimensional Schrödinger-type wave equations with their corresponding effective potentials. Fermions’s potentials are numerically analyzed by serving their some characteristic plots. We also compute the quasinormal frequencies of the chargeless and massive scalar waves. With the aid of those quasinormal frequencies, Bekenstein’s area conjecture is tested for the Grumiller black hole. Thus, the effects of the Rindler acceleration on the waves of fermions and scalars are thoroughly analyzed.
APPLYING ANSOFF’S GROWTH STRATEGY MATRIX TO INNOVATION CLASSIFICATION
Authors: GURCAYLILAR-YENIDOGAN TUGBA , AKSOY SAFAK
Published: November 2017

This study aims to determine innovation capacity of a firm and to investigate the correlations between performance outcomes and innovation types. In this study, a questionnaire-based survey was conducted to classify firms with respect to different novelty degrees of innovation activities in developing new products and the magnitude of market impact shortly after innovations have been introduced and then appraise the association between innovation types and performance outcomes. The data obtained from the Turkish industrial clusters show that the higher firm innovativeness in product and market with a wide-spread diffusion effect of innovations, the greater is the market and production performance. To the best of our knowledge, this study is one of the few studies applying the product-market growth matrix to determine/manage innovation portfolio of firms.
Spectral BEM for the Analysis of Wave Propagation and Fracture Mechanics
Authors: Li Jun , Khodaei Zahra Sharif , Aliabadi M. H.
Published: November 2017

This paper presents a spectral boundary element formulation for analysis of structures subjected to dynamic loading. Two types of spectral elements based on Lobatto polynomials and Legendre polynomials are used. Two-dimensional analyses of elastic wave propagation in solids with and without cracks are carried out in the Laplace frequency domain with both conventional BEM and the spectral BEM. By imposing the requirement of the same level of accuracy, it was found that the use of spectral elements, compared with conventional quadratic elements, reduced the total number of nodes required for modeling high-frequency wave propagation. Benchmark examples included a simple one-dimensional bar for which analytical solution is available and a more complex crack problem where stress intensity factors were evaluated. Special crack tip elements are developed for the first time for the spectral elements to accurately model the crack tip fields. Although more integration points were used for the integrals associated with spectral elements than the conventional quadratic elements, shorter computation times were achieved through the application of the spectral BEM. This indicates that the spectral BEM is a more efficient method for the numerical modeling of structural health monitoring (SHM) processes, in which high-frequency waves are commonly used to detect damage, such as cracks, in structures.
An Advanced Discrete Model with Applications in Medical Science
Authors: Para Bilal Ahmad , Jan Tariq Rashid
Published: November 2017

In this paper, we introduce a new discrete model by compounding two parameter discrete Weibull distribution with Beta distribution of first kind. The proposed model can be nested to different compound distributions on specific parameter settings. The model is a good competitive for zero-inflated models. In addition, we present the basic properties of the new distribution and discuss unimodality, failure rate functions and index of dispersion. Finally, the model is examined with real-life count data from medical sciences to investigate the suitability of the proposed model.
A Study on the Nucleation Mechanism of Nano-Scale Precipitates of 7055 Aluminum Alloy
Authors: Zhang Ping , Wang Youqiang
Published: November 2017

7055 aluminum alloy is a typical age-hardening alloy whose properties change with microstructural evolution as a result of heat treatment. In this paper, the microstructural evolution of the alloy after solid solution treatment and manual aging is examined using SEM, TEM and HADDF. The precipitation, nucleation and growth mechanisms of [Formula: see text] and [Formula: see text] phases are also analyzed. Results show that, as aging proceeds, the Al–Cu phase gradually enlarges and thickens the following precipitation sequence of supersaturated solid solution (SSSS) [Formula: see text] GPI zone [Formula: see text] GPII zone [Formula: see text] phase [Formula: see text] phase; some [Formula: see text] phases formed during aging, which have two different nucleation mechanisms: homogeneous nucleation and heterogeneous nucleation, the [Formula: see text] phases of the latter being marginally larger in size than those of the former. There is a transition in the transformation of (Al3Cu) in GPII zone into [Formula: see text]-phase (Al2Cu). The orientation relation between [Formula: see text] phase and Al matrix is (100)Al//(100)[Formula: see text], (010)Al//(010)[Formula: see text], (001)Al//(001)[Formula: see text]. According to this relationship, [Formula: see text] phase has three variants in the matrix: Variants 1, 2, and 3, which represent the [Formula: see text] phase along {100}Al, {010}Al and {001}Al. As [Formula: see text] phase has a special orientation relation with Al matrix (100)Al//(100)[Formula: see text], (010)Al//(010)[Formula: see text], (001)Al//(001)[Formula: see text], [Formula: see text] phase is distributed in disc form on {001}Al. Significantly larger [Formula: see text] phase can be observed. The orientation relation between S phase and Al matrix is [100]Al//[100]S, [021]Al//[010]S, [012]Al//[001]S. [Formula: see text] phase grows in step form for a period equaling to 1.75-fold unit cell of [Formula: see text]. As [Formula: see text] phase grows, the Cu atoms segregated on the edge of [Formula: see text] phase are gradually consumed.
Rings whose cozero-divisor graph has crosscap number at most two
Authors: Mallika A. , Kala R.
Published: November 2017

Let [Formula: see text] be a commutative ring with identity. The cozero-divisor graph of [Formula: see text], denoted by [Formula: see text], is a graph whose vertex set is [Formula: see text], the set of all non-zero and non-unit elements of [Formula: see text]. Two distinct vertices [Formula: see text] and [Formula: see text] in [Formula: see text] are adjacent if and only if [Formula: see text] and [Formula: see text]. The Crosscap of a graph [Formula: see text], denoted by [Formula: see text], is the minimum integer [Formula: see text] such that the graph can be embedded in the non-orientable surface [Formula: see text]. The planar graph is called [Formula: see text]-outerplanar if removing all the vertices incident on the outer face yields a [Formula: see text]-outerplanar. The Outerplanarity index of a graph [Formula: see text] is the smallest [Formula: see text] such that [Formula: see text] is [Formula: see text]-outerplanar. In this paper, we characterize the class of rings [Formula: see text] (up to isomorphism) for which [Formula: see text]. Further we characterize all finite rings [Formula: see text] (up to isomorphism) for which [Formula: see text] has an outerplanarity index two.
Assessment of Dimensionless Correlations for Prediction of Refrigerant Mass Flow Rate Through Capillary Tubes — A Review
Authors: Rasti Mehdi , Jeong Ji Hwan
Published: November 2017

Capillary tubes are widely used as expansion devices in small-capacity refrigeration systems. Since the refrigerant flow through the capillary tubes is complex, many researchers presented empirical dimensionless correlations to predict the refrigerant mass flow rate. A comprehensive review of the dimensionless correlations for the prediction of refrigerants mass flow rate through straight and coiled capillary tubes depending on their geometry and adiabatic or diabatic capillary tubes depending on the flow configurations has been discussed. A comprehensive review shows that most of previous dimensionless correlations have problems such as discontinuity at the saturated lines or ability to predict the refrigerant mass flow rate only for the capillary tube subcooled inlet condition. The correlations suggested by Rasti et al. and Rasti and Jeong appeared to be general and continuous and these correlations can be used to predict the refrigerant mass flow rate through all the types of capillary tubes with wide range of capillary tube inlet conditions including subcooled liquid, two-phase mixture, and superheated vapor conditions.
Pseudo Bond Graph Model of Thermal Transfers Supported by an Outside Cold Airflow of a Refrigerator to Improve Its Performance
Authors: Aridhi Emna , Abbes Mehdi , Mami Abdelkader
Published: November 2017

This paper aims to prove the efficiency of using the naturally free and abundant cold airflow to improve the cooling inside a household refrigerator and to reduce the energy consumption in Nordic and high altitude countries. The cold airflow is spread out in a cavity covering the side wall of the appliance. This cavity is also connected to the cold outdoor environment through inlet and outlet ducts. For that purpose, a pseudo bond graph (BG) model is proposed to model this installation. It represents the thermal transfers by forced convection in the cavity and the ducts with the ambient and outdoor surroundings. The internal air temperature is computed according to the evaporator temperature and the outside cold airflow that is also computed according to the outside temperature. The simulation results show that the cooling process was speeded up by about 39% and the duration of the compressor functioning was reduced by about 10[Formula: see text]h and 8[Formula: see text]min, which allows reducing the total energy use by 0.88[Formula: see text]kWh, and thus achieving an energy saving of about 34.61%. Experimental data of the outside airflow temperature in Canada during 28 hours in January 2017 are used in the model and allow an energy saving of about 40%.
Quadrotor Thrust Vectoring Control with Time and Jerk Optimal Trajectory Planning in Constant Wind Fields
Authors: Silva João Paulo , De Wagter Christophe , de Croon Guido
Published: November 2017

This paper proposes a trajectory planning and control strategy to optimally visit a given set of waypoints in the presence of wind. First, aerodynamic properties of quadrotors which affect trajectory planning and tracking performance are investigated. Blade flapping, induced and parasitic drag are derived and an extended method to identify all coefficients from flight test data is developed. Then, a three-step approach is suggested to optimize the trajectory. These steps reduce the size of the optimization problem and thereby increase computational efficiency while still guaranteeing near optimal results. The trajectories are optimized for minimal aerodynamic drag and minimal jerk. The derived smooth trajectory generation is compared with traditional trajectory planning consisting of discrete point to point tracking followed by low-pass filtering. The new trajectories yield a clear reduction in maximal needed thrust and in Euler angle aggressiveness. A thrust vectoring controller is designed, which exploits the a priori trajectory information and identified aerodynamic properties. Its performance is compared to a standard PID controller and results show a reduction in tracking delay and an increase in thrust and attitude angle margins, which overall enable faster flight.
Determination of water flow through clayey slurries using computed micro-tomography
Authors: Ito Maki , Azam Shahid
Published: November 2017

The purpose of this study was to develop a clear understanding of water flow through clayey slurries. Computed micro-tomography was used to quantify slurry constituents and validate index properties and hydraulic conductivity. An image analysis method was developed to capture the mechanics of flow through clayey slurries that are difficult to quantify through conventional measurement techniques. A
solids ratio
was defined to identify actual flow paths within a mixture of the solids, water and hydrated grains
.
Likewise, hydraulic radius was re-defined to describe water flow paths (pore throat) thereby eliminating the measurement of shape factor and tortuosity. More importantly, hydraulic conductivity calculated through the new method (and based on Poiseuille's law) corroborated well with the empirical method of Pane & Schiffman (1997) for flocculated slurries.
Engineering geology and tunnelling in the Limmo Peninsula, East London
Authors: Linde-Arias Emilio , Harris David , Ghail Richard
Published: November 2017

The Limmo Peninsula site has some of the most complex geology of London's Crossrail project and was the launching point for four tunnel boring machines (TBMs) to allow construction of Crossrail's eastern running tunnels. It is located in East London,
c.
2 km east of the Canary Wharf business district, adjacent to the River Lea. It consists of a ventilation shaft, an auxiliary shaft, two sprayed concrete lining (SCL) tunnels interconnecting the shafts and four SCL adits for assisting in the launching of the TBMs. As part of the design requirements, some geological formations had to be depressurized from surface wells. The site is geologically complex: it is in the vicinity of a drift-filled hollow and it is located within the area of influence of several tectonic features. A geological ground model developed from important new information obtained during the design stage ground investigations and from direct observations conducted during construction stages reveals an inverted transtensional flower structure (i.e. it is now a transpressional restraining bend). Of special interest are the unusually low values of undrained shear strength of the London Clay associated with the tectonic setting.
Seer
Authors: Diegues Nuno , Romano Paolo , Garbatov Stoyan
Published: November 2017

The ubiquity of multicore processors has led programmers to write parallel and concurrent applications to take advantage of the underlying hardware and speed up their executions. In this context, Transactional Memory (TM) has emerged as a simple and effective synchronization paradigm, via the familiar abstraction of atomic transactions.

After many years of intense research, major processor manufacturers (including Intel) have recently released mainstream processors with hardware support for TM (HTM).

In this work, we study a relevant issue with great impact on the performance of HTM. Due to the optimistic and inherently limited nature of HTM, transactions may have to be aborted and restarted numerous times, without any progress guarantee. As a result, it is up to the software library that regulates the HTM usage to ensure progress and optimize performance. Transaction scheduling is probably one of the most well-studied and effective techniques to achieve these goals.

However, these recent mainstream HTMs have some technical limitations that prevent the adoption of known scheduling techniques: unlike software implementations of TM used in the past, existing HTMs provide limited or no information on which memory regions or contending transactions caused the abort.

To address this crucial issue for HTMs, we propose S
eer
, a software scheduler that addresses precisely this restriction of HTM by leveraging on an online probabilistic inference technique that identifies the most likely conflict relations and establishes a dynamic locking scheme to serialize transactions in a fine-grained manner. The key idea of our solution is to constrain the portions of parallelism that are affecting negatively the whole system. As a result, this not only prevents performance reduction but also in fact unveils further scalability and performance for HTM. Via an extensive evaluation study, we show that S
eer
improves the performance of the Intel’s HTM by up to 3.6×, and by 65% on average across all concurrency degrees and benchmarks on a large processor with 28 cores.
Toward Optimal Self-Adjusting Heaps
Authors: Elmasry Amr
Published: November 2017

We give a variant of the pairing heaps that achieves the following amortized costs:
O
(1) per
find-min
and
insert
,
O
(log log
n
) per
decrease-key
and
meld
,
O
(log
n
) per
delete-min
; where
n
is the number of elements in the resulting heap on which the operation is performed. These bounds are the best known for any self-adjusting heap and match two lower bounds, one established by Fredman and the other by Iacono and Özkan, for a family of self-adjusting heaps that generalizes the pairing heaps but do not include our variant. We further show how to reduce the amortized cost for
meld
to be paid by the other operations, on the expense of increasing that of
delete-min
to
O
(log
n
+ log log
N
), where
N
is the total number of elements in the collection of heaps of the data structure (not just the heap under consideration by the operation).
Sport science internships for learning: a critical view
Authors: Malone James J.
Published: November 2017

Sport science has gained vast popularity with students who have an interest in both physiology and the underpinning mechanisms of exercise concerning performance and health. The high numbers of graduates each year, coupled with the low number of graduate positions working in sports, has led to a high level of competition between students. To stand out from the crowd, sport science students may undertake an internship placement as part of their course, designed to enhance theoretical, practical, and soft skills in an applied setting. In the present article, we highlight some of the positives and negatives of sport science internships and ways in which they can be implemented and facilitated. Suggestions have also been provided to make students more aware of the reality of working in professional sports, which includes awareness of the potential for long and unsociable hours of work.