bluuebunny/crossref_metadata_2025 huggingface dataset:
EVIDENCE FOR THE RAPID FORMATION OF LOW-MASS EARLY-TYPE GALAXIES IN DENSE ENVIRONMENTS
Authors: Liu Yiqing , Peng Eric W. , Blakeslee John , Côté Patrick , Ferrarese Laura , Jordán Andrés , Puzia Thomas H. , Toloba Elisa , Zhang Hong-Xin
Published: February 2016

We explore the environmental dependence of star formation timescales in low-mass galaxies using the [α/Fe] abundance ratio as an evolutionary clock. We present integrated [α/Fe] measurements for 11 low-mass (

) early-type galaxies (ETGs) with a large range of cluster-centric distance in the Virgo Cluster. We find a gradient in [α/Fe], where the galaxies closest to the cluster center (the cD galaxy, M87) have the highest values. This trend is driven by galaxies within a projected radius of 0.4 Mpc (0.26 times the virial radius of Virgo A), all of which have super-solar [α/Fe]. Galaxies in this mass range exhibit a large scatter in the [α/Fe]–σ diagram, and do not obviously lie on an extension of the relation defined by massive ETGs. In addition, we find a correlation between [α/Fe] and globular cluster specific frequency (S

N
), suggesting that low-mass ETGs that formed their stars over a short period of time were also efficient at forming massive star clusters. The innermost low-mass ETGs in our sample have [α/Fe] values comparable to that of M87, implying that environment is the controlling factor for star formation timescales in dense regions. These low-mass galaxies could be the surviving counterparts of the objects that have already been accreted into the halo of M87, and may be the link between present-day low-mass galaxies and the old, metal-poor, high-[α/Fe], high-S

N
stellar populations seen in the outer halos of massive ETGs.
INTERPLAY AMONG COOLING, AGN FEEDBACK, AND ANISOTROPIC CONDUCTION IN THE COOL CORES OF GALAXY CLUSTERS
Authors: Karen Yang H.-Y. , Reynolds Christopher S.
Published: February 2016

Feedback from the active galactic nuclei (AGNs) is one of the most promising heating mechanisms to circumvent the cooling-flow problem in galaxy clusters. However, the role of thermal conduction remains unclear. Previous studies have shown that anisotropic thermal conduction in cluster cool cores (CCs) could drive the heat-flux-driven buoyancy instabilities (HBIs) that reorient the field lines in the azimuthal directions and isolate the cores from conductive heating from the outskirts. However, how the AGN interacts with the HBI is still unknown. To understand these interwined processes, we perform the first 3D magnetohydrodynamic simulations of isolated CC clusters that include anisotropic conduction, radiative cooling, and AGN feedback. We find the following: (1) For realistic magnetic field strengths in clusters, magnetic tension can suppress a significant portion of HBI-unstable modes, and thus the HBI is either completely inhibited or significantly impaired, depending on the unknown magnetic field coherence length. (2) Turbulence driven by AGN jets can effectively randomize magnetic field lines and sustain conductivity at ∼1/3 of the Spitzer value; however, the AGN-driven turbulence is not volume filling. (3) Conductive heating within the cores could contribute to ∼10% of the radiative losses in Perseus-like clusters and up to ∼50% for clusters twice the mass of Perseus. (4) Thermal conduction has various impacts on the AGN activity and intracluster medium properties for the hottest clusters, which may be searched by future observations to constrain the level of conductivity in clusters. The distribution of cold gas and the implications are also discussed.
CONSTRAINTS ON FEEDBACK IN THE LOCAL UNIVERSE: THE RELATION BETWEEN STAR FORMATION AND AGN ACTIVITY IN EARLY-TYPE GALAXIES
Authors: Vaddi Sravani , O’Dea Christopher P. , Baum Stefi A. , Whitmore Samantha , Ahmed Rabeea , Pierce Katherine , Leary Sara
Published: February 2016

We address the relation between star formation and active galactic nucleus (AGN) activity in a sample of 231 nearby (0.0002 < z < 0.0358) early-type galaxies by carrying out a multi-wavelength study using archival observations in the UV, IR, and radio. Our results indicate that early-type galaxies in the current epoch are rarely powerful AGNs, with

for a majority of the galaxies. Only massive galaxies are capable of hosting powerful radio sources while less massive galaxies are hosts to lower radio power sources. Evidence of ongoing star formation is seen in approximately 7% of the sample. The star formation rate (SFR) of these galaxies is less than 0.1 M
⊙ yr−1. They also tend to be radio faint (

). There is a nearly equal fraction of star-forming galaxies in radio faint (

) and radio bright galaxies (

) suggesting that both star formation and radio mode feedback are constrained to be very low in our sample. We notice that our galaxy sample and the Brightest Cluster Galaxies follow similar trends in radio power versus SFR. This may be produced if both radio power and SFR are related to stellar mass.
THE RADIO/X-RAY CORRELATION AND BLACK HOLE FUNDAMENTAL PLANE FOR YOUNG RADIO SOURCES: IMPLICATIONS FOR X-RAY ORIGIN AND ACCRETION MODE
Authors: Fan Xu-Liang , Bai Jin-Ming
Published: February 2016

We find that the young radio sources (gigahertz-peaked spectrum and compact steep spectrum radio sources) follow in the radio/X-ray correlation with

(

), and the fundamental plane of black hole activity with the form

and the intrinsic scatter

. The flatter coefficient between radio and X-ray bands denies the jet origin of the X-ray emission in these types of sources. Meanwhile, the higher ratio of X-ray luminosity to Eddington luminosity (

) suggests that the X-ray emission is produced by the hot corona coupling with the standard thin disk. The deviation with the radiative efficient fundamental plane proposed by Dong et al. is mainly due to the extended radio emission in young radio sources. This fundamental plane manifests that even the kiloparsec-scaled radio emission has a tight connection with the accretion process, and could be suitable for the radio-loud active galactic nuclei whose radio and X-ray emission are dominated by the extended jets and the radiative efficient accretion flow, respectively. Otherwise, the high-excitation galaxies and low-excitation galaxies do not have obvious distinctions in the radio/X-ray correlation and the fundamental plane.
THEORETICAL LIMITS ON MAGNETIC FIELD STRENGTHS IN LOW-MASS STARS
Authors: Browning Matthew K. , Weber Maria A. , Chabrier Gilles , Massey Angela P.
Published: February 2016

Observations have suggested that some low-mass stars have larger radii than predicted by 1D structure models. Some theoretical models have invoked very strong interior magnetic fields (of order 1 MG or more) as a possible cause of such large radii. Whether fields of that strength could in principle be generated by dynamo action in these objects is unclear, and we do not address the matter directly. Instead, we examine whether such fields could remain in the interior of a low-mass object for a significant amount of time, and whether they would have any other obvious signatures. First, we estimate the timescales for the loss of strong fields by magnetic buoyancy instabilities. We consider a range of field strengths and simple morphologies, including both idealized flux tubes and smooth layers of field. We confirm some of our analytical estimates using thin flux tube magnetohydrodynamic simulations of the rise of buoyant fields in a fully convective M-dwarf. Separately, we consider the Ohmic dissipation of such fields. We find that dissipation provides a complementary constraint to buoyancy: while small-scale, fibril fields might be regenerated faster than they rise, the dissipative heating associated with such fields would in some cases greatly exceed the luminosity of the star. We show how these constraints combine to yield limits on the internal field strength and morphology in low-mass stars. In particular, we find that for stars of 0.3 solar masses, no fields in flux tubes stronger than about 800 kG are simultaneously consistent with both constraints.
COMET 252P/LINEAR: BORN (ALMOST) DEAD?
Authors: Ye (叶泉志) Quan-Zhi , Brown Peter G. , Wiegert Paul A.
Published: February 2016

Previous studies have revealed Jupiter-family comet 252P/LINEAR as a comet that was recently transported into the near-Earth object (NEO) region in ∼1800 AD yet only being weakly active. In this Letter, we examine the “formed (almost) dead” hypothesis for 252P/LINEAR using both dynamical and observational approaches. By statistically examining the dynamical evolution of 252P/LINEAR over a period of 107 years, we find the median elapsed residency in the NEO region to be 4 × 102 years, which highlights the likelihood of 252P/LINEAR as an (almost) first-time NEO. With available cometary and meteor observations, we find the dust production rate of 252P/LINEAR to be on the order of 106 kg per orbit since its entry to the NEO region. These two lines of evidence support the hypothesis that the comet was likely to have formed in a volatile-poor environment. Cometary and meteor observations during the comet's unprecedented close approach to the Earth around 2016 March 21 would be useful for understanding of the surface and evolutionary properties of this unique comet.
Knowledge of sustainable development among geography students in Slovenia
Authors: Kovačič Gregor , Brečko Grubar Valentina
Published: February 2016

The paper presents the results of the survey conducted among geography students of the three public universities in Slovenia regarding their knowledge of sustainable development and the ways of gaining this knowledge. On the basis of 160 questionnaires, distributed mainly among the first-level students, we concluded that the students assess their knowledge of sustainable development as very good. However, they lack knowledge about social aspects of sustainable development. They gained most of their respective knowledge through formal education. The knowledge of sustainable development improves in the course of study years on the first level and particularly on the second level. This fact and the answers regarding connectedness of study programmes with the topic of sustainable development (also the courses mentioned by the students) show that sustainable development is well integrated into geography study programmes.
Anisotropic spaces in Romania: a case study of the Timiş-Cerna Corridor
Authors: Creţan Remus , Jucu Sebastian , Antoni Maria
Published: February 2016

This paper presents a critical discussion of Romania’s south-west, analyzing the proposal that the Timiş-Cerna Corridor should be systemically considered anisotropic. The aim of our paper is to test the possible anisotropic matrix system by using a methods approach based on interpreting human and material mobilities in the area. We use the theoretical framework of regional geography in a systemic context and specifically the concept of anisotropy defined as a territorial anomaly in homogenous and polarized regions, in order to reveal the social and physical relations in which anisotropy is embedded. Our results show that the Timiş-Cerna Corridor is an anisotropic area fitting the structural system of this specific type of space as the dynamics of flows inside the axis are asymmetrical, generating disparities, while transit flows are predominant.
Geomorphology and wine: the case of Malvasia in the Vipava valley, Slovenia
Authors: Jamšek Rupnik Petra , Čuš Franc , Šmuc Andrej
Published: February 2016

The concept of terroir incorporates interaction between geogenic and anthropogenic parameters and defines the typicity and quality of wine in a particular geographic area. Geomorphology represents one of the most important geogenic parameters of terroir. In 2008 we produced two wines from two different sites located within the same vineyard in the Vipava valley (Slovenia). Despite identical vine-growing and winemaking techniques, the two sites yielded grapes and wines of different quality. Both sites are identical in terms of macroclimate and bedrock, thus the differences are related to soil composition, drainage and microclimate, all directly linked to different geomorphic positions.
Être réfugié à Delhi
Authors: Baujard Julie
Published: February 2016

Bien que l’Inde ne reconnaisse pas légalement le statut international de réfugié, elle accueille de nombreuses personnes qui, parties sous la contrainte de leur pays d’origine, sollicitent un refuge légal auprès d’un autre État c’est-à-dire des réfugiés. Depuis son indépendance, en 1947, plusieurs grandes crises se sont produites dans la région sud-asiatique, générant un nombre important d’entrée sur son territoire : réfugiés de la partition du sous-continent en 1947, Tibétains depuis 1959, Chakma du Pakistan oriental au début des années 1960, Bengalis en 1971, Afghans à partir de 1979, Tamouls sri lankais depuis 1983, Birmans à partir de 1988, Bhoutanais dans les années 1990. Certains de ces réfugiés ont été ou sont accueillis dans des camps plus ou moins ouverts, tandis que d’autres vivent dans les campagnes et les villes indiennes, au sein de la population locale.
Qatar’s “White-collar” Indians
Authors: Kanchana Radhika
Published: February 2016

The paper is a descriptive narrative of the Indian expatriates in Qatar, covering two aspects. One dimension highlights the profile of the Qatari Indian community primarily in the white-collar occupations and the second dimension explores some of the differences of the group, in comparison with its counterpart in the United Arab Emirates (UAE). The basis for the work is a two-month fieldwork done as part of doctoral research in late 2009 (15 days in Qatar and the rest in the UAE). The region of Gulf Cooperation Council (GCC) collectively has a significant population of Indians in its total size of foreign migrants. All the countries share the practice of importing labour, extensively from the 1970s since the discovery of oil and the rapid development in the region. However, it is relevant to understand that the individual member countries (namely Saudi Arabia, Qatar, Oman, Bahrain, Kuwait, and United Arab Emirates) do not have the same typology with regard to the Indian-migrant group.
Network Former Mixing (NFM) Effects in Ion-Conducting Glasses - Structure/Property Correlations Studied by Modern Solid-State NMR Techniques
Authors: Eckert Hellmut
Published: February 2016

Glassy solid electrolytes are important integral components for all-solid-state devices for energy storage and conversion. The use of multiple network formers is an important part of their design strategy for specific applications. In many glass systems the interaction between the different network formers results in strongly non-linear variations in physical properties (network former mixing (NFM) effects), requiring a detailed understanding on a structural basis.The issues to be addressed involve both the structural organization and connectivities within the framework, the local environments and spatial distributions of the mobile ions, and the dynamical aspects of ion transport, to be discussed in relation to possible phase separation or nano-segregation effects. Besides Raman and X-ray photoelectron spectroscopies, solid state nuclear magnetic resonance (NMR) methods are particularly useful for providing detailed answers to such issues. The present review introduces the basic principles of modern solid state NMR methods and their applications to glass structure, with a particular focus on the characterization of network-former mixing effects in the most common lithium and sodium conducting oxide and chalcogenide glass systems. Based on the current state of the literature reviewed in the present work, some emerging general principles governing structure/property correlations are identified, to be tested by further experimenteation in the future.
Physical Insights on Charge Transport Mechanism and the LF Noise Behavior in Oxidized Si Structures with Ge Nanoclusters
Authors: Lysenko Vladimir , Gomeniuk Yurii V. , Kudina Valeriya N. , Garbar Nikolay , Kondratenko Sergey , Kozyrev Yurii N.
Published: February 2016

To ascertain physical mechanism of charge transport in Si/SiOx structures with Ge nanoclusters the measurements of their DC and AC conductivity, and also the low-frequency measurements were performed. It was revealed that in the temperatures range 110 – 250 K the characteristics measured are governed by the hopping mechanism of charge transport. The model proposed suggests that the charge hopping becomes possible due to the band of localized states inducing in the bandgap of silicon substrate when Ge nanoclusters are introduced. The model was used to estimate some parameters of hopping transport. Also, the analysis of the low-frequency noise measured for Si/SiOx structures with Ge nanoclusters allowed to ascertain the mechanism of charge hopping resulting in strong temperature dependence of the 1/f noise measured.
Silicon Nanocrystalline Nonvolatile Memory - Characterization and Analysis
Authors: Ievtukh Valerii , Nazarov A.
Published: February 2016

In this work, nanocrystal nonvolatile memory devices comprising of silicon nanocrystals located in gate oxide of MOS structure, were comprehensively studied on specialized modular data acquisition setup developed for capacitance-voltage measurements. The memory window formation, memory window retention and charge relaxation experimental methods were used to study the trapping/emission processes inside the dielectric layer of MOS capacitor memory. The trapping/emission processes were studied in standard bipolar memory mode and in new unipolar memory mode, which is specific for nanocrystalline nonvolatile memory. The analysis of experimental results shown that unipolar programming mode is more favourable for nanocrystalline memory operation due to lower wearing out and higher breakdown immunity of the MOS device’s oxide. The study was performed for two types of nanocrystalline memory devices: with one and two silicon nanocrystalline 2D layers in oxide of MOS structure correspondingly. The electrostatic modelling was presented to explain the experimental results.
FePt Thin Films – Prospective Materials for Ultrahigh Density Magnetic Recording
Authors: Vladymyrskyi Igor A. , Oleshkevych Anna I. , Sidorenko S.I. , Makogon Yurii N.
Published: February 2016

Constant increase of magnetic recording density requires application of modern ferromagnetic materials with high value of magnetic anisotropy constant and coercivity. Thin films on the bases of L10-FePt ordered phase is one of such materials. However, practical application of such materials requires to solve a number of materials science problems such as decrease of ordered phase formation temperature, formation of its predominantly oriented grains and increase of coercivity. Factors that affect structure formation and properties of FePt based films have been examined in this study. A number of modern studies aimed on solving problems mentioned above have been analyzed.
Electron Transport through Thin SiO2 Films Containing Si Nanoclusters
Authors: Kizjak Anatoliy , Evtukh Anatoliy , Steblova Olga , Pedchenko Yuriy
Published: February 2016

The electron transport mechanisms through nanocomposite SiO2(Si) films containing Si nanoclusters into dielectric SiO2 matrix have been investigated. SiO2(Si) films were obtained by oxide assisted growth. At the first stage the SiOx films with different content of excess Si were deposited by LP CVD method. Second stage includes high temperature (T=1100 C) annealing of SiOx films that promotes formation of Si nanocrystals. Current transport through SiO2(Si) films were studied in temperature range 100-350 K. As it was observed the dominant mechanism of electron transport depends as on voltage and temperature. The Mott’s conductivity caused by traps near Fermi level was revealed in low-voltage range for all temperatures. At increasing the voltage the SCLC conductivity is observed for films with higher content of excess silicon while in case low content of Si the Pool-Frenkel mechanism dominates. The further increase in voltage results in a double carrier injection.
Development and Modeling of Thermal Energy Harvesting Setup
Authors: Domański Krzysztof , Prokaryn Piotr , Tomaszewski Daniel , Marchewka Michał , Grabiec Piotr
Published: February 2016

A setup for a thermal energy harvesting based on a conversion of a thermal energy into a mechanical energy followed by a conversion of the mechanical energy into an electric field energy has been developed. The key elements of such a setup are a bimetal spring and electrodes covered by electret layers with a permanent charge. The electrodes are kept at different temperatures. The bimetal spring exchanges the thermal energy with the "hot" and "cold" electrodes. The heating and cooling stimulates the spring vibratios. During the vibrations the spring acts as a common plate of two variable capacitors. The electrodes with the electret layers are the fixed plates of these capacitors. The charge induced continuously at the plates of the capacitors is transferred via a rectifying circuit to the external capacitor.Several aspects of the setup development have been considered, including different electret materials, different methods of the electret charging, and different load capacitors.A compact model of the charging effect has been also developed. It has been implemented in Qucs program, where it is represented as a so-called equation defined device component.
Selected Questions Related to Characterization of MEMS Structures Comprising PZT Piezo Layer
Authors: Zając Jerzy , Gutt Tomasz , Piasecki Tomasz , Grabiec Piotr
Published: February 2016

PZT (lead zirconium titanate) is an intermetallic compound exhibiting piezoelectric, ferroelectric, and pyroelectric properties. The perovskite crystallographic structure of the PZT is responsible for the above effects. MEMS structures with piezo layers can be used as sensors, actuators, or converters. The abilities of piezo materials to generate an electric charge as a response to stress and a change of shape as a response to electric field are very attractive in numerous applications. Cantilever structures with a mass attached can accordingly be used as energy harvesters converting energy of environment vibrations. Other applications of cantilevers are small displacement sensors or actuators in micro/nanoscale. Membrane structures can work as ultrasonic transducers. If properly shaped cavity is produced, the structure may be used as a part of ink printer head or as a pressure sensor.For physical description of piezo phenomena, constitutive equations in several forms are used. They work well for bulk piezoelectric, although for thin layers deposited on silicon or similar substrate, piezoelectric coupling coefficients must be redefined because of the interaction of thin piezo layer and thicker substrate.Typical electric characterization of piezo MEMS structures includes CV and IV measurements. QV (charge-voltage) hysteresis loop study is an additional method used for this characterization. Complex electromechanical methods are used for surveying piezoelectric coupling coefficients. These methods employ mechanic actuation and electric response Q measurements or AC electric V (voltage) excitation and measurement of mechanical response v (velocity). In the second case, a very precise tool for velocity evaluation is necessary. Such tool could be for example laser Doppler vibrometer, enabling measurements of picometer resolution in several MHz bandwidth. In many cases resonance features of structures have revealed themselves interesting and became a subject of the study. Some vibrometers make measurement of micro cantilever vibrations excited by Brownian movement of air particles possible.
Steep-Slope Devices: Prospects and Challenges
Authors: Gnani Elena , Baravelli Emanuele , Maiorano Pasquale , Gnudi Antonio , Reggiani Susanna , Baccarani Giorgio
Published: February 2016

In this work, an overview is given on the prospects and challenges of two novel device concepts,namely the Tunnel FET (TFET) and the Superlattice FET (SL-FET). The optimization effort ofhomo- and hetero-junction TFETs carried out so far shows that these devices can provide an advantageover CMOS FETs only for very-low power and low-performance niche applications, so long asthe supply voltage is scaled below 300 mV. The required materials for homojunction TFETs are lowbandgap semiconductors, such as InAs and InGaAs; for heterojunction TFETs the best semiconductorpair appears to be (Al)GaSb-InAs. Several technological problems are still unsolved: poor qualityof the oxide interface with III-V materials and device variability are probably the most important. The SL-FET represents in principle a better device concept, as it provides outstanding performance and meets nearly all targets of the high performance (HP), low operating power (LOP) and low standby power (LSTP) of the ITRS at VDD = 0.4V. A suitably-designedInGaAs-InAlAs SL-FET has turned out to provide the best simulation results. However, the fabricationprocess of SL-FETs is much more complex, as it requires molecular epitaxy to deposit multiplelayers with a very strict control of their nanometric thickness. Besides, vertical devices can poseunexpected problems as far as layout organization and parasitics are concerned.
Photoelectric Phenomena and Photoelectric Characterization Methods of the MOS System - Basics and New Developments
Authors: Przewlocki Henryk M.
Published: February 2016

In this article photoelectric phenomena taking place in the MOS system will be discussed and the classical theory of these phenomena will be presented. This will be followed by pointing out some shortcomings of this theory and presentation of our contributions which eliminate these shortcomings and allow development of new MOS system characterization methods.
Micro- and Nanotextured Silicon for Antireflective Coatings of Solar Cells
Authors: Druzhinin Anatoly , Yerokhov Valery , Nichkalo Stepan , Berezhanskyi Yevhen
Published: February 2016

The paper deals with obtaining of textured silicon surfaces by chemical etching. As a result of experiments based on the modification and optimization of obtaining a textured silicon, several methods of chemical texturing of the crystalline silicon surface were developed. It was shown that modified isotropic and anisotropic etching methods are applicable to create a microrelief on the surface of silicon substrate. These methods in addition to their high conversion efficiency can be used for both mono- and multicrystalline silicon which would ensure their industrial use.
Optical and Electron-Beam Recording of Surface Relief’s Using Ge5As37S58–Se Nanomultilayers as Registering Media
Authors: Stronski Alexander , Achimova Elena , Paiuk Oleksandr , Meshalkin Alexei , Abashkin Vladimir , Lytvyn Oksana , Sergeev Sergei , Prisacar Alexander , Oleksenko Pavel , Triduh Genadii
Published: February 2016

Processes of e-beam and holographic recording of surface-relief structures using Ge5As37S58–Se multilayer nanostructures as registering media were studied in this paper. Optical properties of Ge5As37S58, Se layers and Ge5As37S58–Se multilayer nanostructures were investigated. Spectral dependencies of refractive index were analyzed within the frames of single-oscillator model. Values of optical band gaps for Ge5As37S58, Se layers and Ge5As37S58–Se multilayer nanostructures were obtained from Tauc dependencies. Holographic recording process depends on the polarization of the recording beams. Using e-beam and holographic recording diffraction gratings and other elements were recorded in Ge5As37S58–Se multilayer nanostructures.
Mathematical Model of Anisotropic Elastoplastic Material
Authors: Erisov Yaroslav A.
Published: February 2016

The work considers some techniques for defining the stress state during computer modelling of metal-forming processes. A mathematical model of anisotropic elastoplastic material has been developed and an algorithm of computing the stress-strain behavior according to this model has been described.
Virtual Material Model with the Given Crystallographic Orientation of the Structure
Authors: Grechnikov Fedor V. , Erisov Yaroslav A.
Published: February 2016

The article represents the theoretical basis for the generation of virtual material models with the given crystallographic orientation (CGO) of the structure in metals and alloys with the cubic crystal lattice. The obtained functional interrelations allow to take into consideration a metal sheet CGO in technological calculations of metal forming processes and, most significantly, a priori by means of calculations to determine the structure CGO meeting the requirements of increasing the materials formability and the product performance. It is given an example of the implementation of the calculated CGO of the structure while rolling can sheet from aluminum alloy 3104.
Combined Isothermal Drawing of Axissymmetrical Parts Made out of Anisotropic Materials in Mode of Short-Time Creeping
Authors: Yakovlev Sergey Sergeevich , Pilipenko Olga Vasilievna , Pasynkov Andrey Aleksandrovich
Published: February 2016

Shown are results of theoretical and experimental research of force modes and limit possibilities of the first and subsequent operations of combined isothermal drawing of axisymmetric parts made out of anisotropic materials through conic and radial matrixes in the mode of short-time creeping. Studied was straining of anisotropic material under conditions of short-time creeping. We ignore the elastic components of strain. We introduced potential straining speeds for an anisotropic body under conditions of short-time creeping. Found was the effect of technological parameters, anisotropy of mechanical properties, and of age-hardening upon the stress condition, the force modes of the operation, and upon the design margin of strain during the first and subsequent operations of combined drawing. Experimental research was carried out for the force conditions and possible limits of straining during the first and second operations of combined isothermal drawing with convex-face and conic matrices in the mode of short-time creeping. Comparing the results of theoretical and experimental research for force modes and strain limits during the first and subsequent operations of combined drawing has shown their satisfactory similarity (up to 5% - 10%).
Development of Methods and Research on High Voltage Capacitor Welding
Authors: Nescoromniy S.V. , Ageev S.O. , Strizhakov E.L.
Published: February 2016

The report shows the classification of methods of high-voltage capacitor welding (HVCW) with magnetic drive pulse applied to the preparation of joints such as "rod - drive" of non-ferrous metals and alloys.
Researches of processing methods of process of HVCW are provided.
The ranges of energetic, geometrical parameters are defined and dependences of durability of welded connections are given.
The hypothesis is offered and usage considerations on HVCW are made.
Computer Simulation of the Half-Tore Forming Process from a Ring Blank
Authors: Suleymanova Ilmira , Shlyapugin Aleksey , Erisov Yaroslav A.
Published: February 2016

This paper presents the theoretical foundations and methodology of the modeling process of forming a half ring alloy blank AMg5M in software product Pam-Stamp. At the following technological sizes of a half-tore: the blank radius 516.5 mm; hole’s radius R0=480.74 mm, distance from the generating circle center to the axis of rotation R1=714 mm, the generating circle radius Rp=93 mm, curvature radius of die Rd=16 mm, the process is stable. The results of numerical analysis of the drawing half-tore from the ring blank directed to determining the optimal process parameters are revealed. Modeling shows that the size of the holes in the blank has a significant influence on the distribution of strain along the generatrix of the stamped parts. Using the ring blank reduces the probability of wrinkling in the free areas.
Directional Thickness Alteration of a Thin-Walled Ring Blank Using Flanging and Forming for the Purpose of Receiving Conical Part
Authors: Demyanenko E.G. , Popov I.P.
Published: February 2016

In this article the flanging method of thin-walled ring blanks using the elastic punch and rigid die scheme is investigated. Presence of a cylindrical portion near the larger edge and a flat area at the side of the blank hole is mandatory. Such conditions allow producing conical parts with minimal thickness variation by altering height of the cylindrical portion. Conducted experimental studies showed that the minimal thickness variation values are not exceeding 16% for different materials and relative thicknesses less than 0,01.
SHS Metallurgy of NiAl-Based Alloy
Authors: Yukhvid V.I. , Alymov M.I. , Sanin Vladimir N. , Andreev D.E.
Published: February 2016

Highly caloric mixtures of metal oxides with reducing agents used in SHS metallurgy can burn at combustion temperatures well above the melting point of final products, which ensures formation of cast products. The data of basic research in the field allowed us to suggest methods for manufacturing new cast nickel aluminides based alloy.
Constructional Materials Quality Management According to the Scanning Thermal Analyzer
Authors: Mikheev V.A. , Doroshko G.P. , Ilyukhin V.N.
Published: February 2016

Structural material composition determine its structure not ambiguously. The physical and chemical nature of the linkage elements and materials of its parts act on the construction material structure and the final properties. The study of this connection in materials using the methods of physical and chemical analysis is based on the detection and measurement of continuous external influences and averaged thermal response. However, to control internal processes in the contact zones at the phase boundaries and structural elements not enough. In order to effectively control the quality of the construction material was found the solution to implement a comprehensive by the formation of a set of two alternative methods, in the form of a scanning thermal analyzer and a device for the rated thermal activation combine substances.
Efficiency Improvement of Metal Lathing by Using of an Evaluation Technique of Assembly Machine Tools Quality
Authors: Vasilega D.S. , Ostapenko M.S.
Published: February 2016

They defined conditions of use, calculated a composite index of quality for different tools, chose a machine tool according to its quality evaluation, calculated efficiency of processing by tools with different parameters for a certain production operation.
Structural Strength of Materials as a Factor to Ensure the Quality of Machine Parts
Authors: Frolova Elena , Trunov V. , Kuisokov Т.
Published: February 2016

In this paper, the influence on the structural strength of the three groups of factors: performance, technology and design, from the standpoint of their influence on the final quality details
Application of the Method of Performance Evaluation of the Production Process Design Using Associative Design
Authors: Klochkov Yury , Gazizulina Albina
Published: February 2016

The article is devoted to the application of the method of performance evaluation of the production process design, using associative design. A number of approaches to estimation of efficiency of associative design, which are based on estimates of the design timing, the number of imposed changes at appropriate stages of the product life cycle.
Multi-Block and Multi-Station Pulse-Magnetic Installations
Authors: Yusupov Rinat Yu. , Glushchenkov Vladimir
Published: February 2016

The paper describes principles of construction of multi-block and multi-station pulse-magnetic installations. Main requirements for selection of elements of energy storages of installations with high stored energy and high frequency of the discharging current are presented. Examples of hardware implementation of the installations are shown.
Determination of One-Channel Press Dies Operating Corbels
Authors: Kargin Vladimir Rodionovich , Kargin Boris Vladimirovich
Published: February 2016

The dimensions calculation methods of one-channel dies operating corbels for solid profiles pressing are described, these methods are based on similarity theory and dimensional analysis. According to these methods, setting dimensions of the operating corbel on the K profile section, it is possible to calculate operating corbels dimensions on each other section of the i profile, depending on their position relative to the die center, ensuring the outflow evenness. Calculation example of the die operating corbels for the pressing of the ribbed profile made of AV alloy is given.
Evaluation of Formability of Thin Sheet Metal from Mechanical Properties
Authors: Guk Sergey
Published: February 2016

The evaluation of formability for sheet metals by means of different tests such as hole-expansion and forming limit tests is widely used in industry. The experimental efforts for these tests and the scatter of the results are much higher than those for the identification of the mechanical properties of various material charges for the same material grade in tensile test. Difficulties in accurate formability evaluation for new steel grades, such as AHSS, have necessitated a review of the existing prediction methods. Consequently, a new formability criterion was developed from the statistical relations of parameters for approximately fifty steel grades in various thickness ranges. The criterion considers the combination of mechanical properties from the tensile testing as the yield strength, tensile strength and total elongation and plastic deformation energy in a single value. The quality ranking of different charges and coils was made by using of the criterion as well as, for comparison, other well-known criteria which are currently used in the industry. The results obtained involving the new formability criterion seems to be accurate for a wide range of material grades and thicknesses, from the viewpoint of automotive design requirements.
Material Flow in Mg-PSZ Particle Reinforced TRIP-Matrix-Composites due to Hot-Rolling
Authors: Pranke Katja , Guk Sergey
Published: February 2016

The material flow in particle reinforced metal-matrix-composites (MMC) had been investigated. The composite consisted of TRIP steel and magnesium stabilized ZrO2 particles (Mg‑PSZ) in volume fractions of 0 %, 5 % and 20 %. The basic materials were produced by hot-pressing and showed a very homogeneous particle distribution and a almost full density. Then the samples were cut to wedge shape and hot-rolled with a constant roll gap. Caused by the shape, the true strain increased over the length and reached a maximum of true strain of 0.6. The strain rate was set to be higher than 0.1 and lower than 10/ s. After rolling, it was possible to combine rolling force, true strain and the material flow due to the grid on the surface. With an increase in volume fraction of Mg‑PSZ the rolling force increases as well. Metallographic examinations were performed to determine and document the flow of particles within the composite due to true strain conditions. It was found that the particles flow with the base material and turn parallel to the rolling direction. This effect was measured using the degree of orientation of partially oriented linear structure elements Ω12, according to ASTM E 1268-01. The index was increasing with increasing true strain value. Further microscopic examination showed debonding of the interface between particles and matrix-material. For MMC’s having a volume fraction of 20 % Mg-PSZ a true strain at fracture of 0.5 to 0.6 was determined.
Engineered Wood Composite of Laminated Veneer Lumber: Physical and Mechanical Properties
Authors: Liew Kang Chiang , Grace Singan
Published: February 2016

Utilisation of forest plantation species such as Acacia hybrid has been used in wood-based industry as an alternative to solid wood that was usually attained from natural forest. While, the under-utilised species such as Mangifera sp. is not often been used as raw material for wood products, in this study, laminated veneer lumber (LVL) has been produced from Acacia hybrid and Mangifera sp. The physical and mechanical properties of LVL were determined and compared. For physical testing, the range value of moisture content was 9.41% to 14.56%, Density was 487.90 kg/m3 to 699.10 kg/m3, thickness swelling was between 0.20% to 6.05%, water absorption between 32.71% to 91.25%, and rate of delamination from 0% to 100%. Mangifera sp. LVL has higher moisture content, rate of delamination, and water absorbency. In mechanical testing, it is been found that Acacia hybrid LVL has overall higher strength compared to Mangifera sp. LVL, in terms of static bending strength (MOR and MOE), shear strength, and compression strength. Range of value for MOR was between 10.27 N/mm2 to 129.99 N/mm2, MOE between 1138 N/mm2 to 16472.93 N/mm2, shear strength between 0.43 N/mm2 to 3.40 N/mm2, and compression between 139.45 N/mm2 to 6749.74 N/mm2. For physical testing, the overall result of p-value for moisture content, water absorption, and delamination were significant at p ≤ 0.05, while density and thickness swelling were not significant at p ≥ 0.05. For overall result, the p-value for static bending strength (MOR and MOE) was significant at p ≤ 0.05 while for shear strength and compression strength were not significant at p ≥ 0.05.
Carbohydrate-Based Advanced Biomaterials for Food Sustainability: A Review
Authors: Valdés Arantzazu , Garrigós María Carmen
Published: February 2016

The quality and safety of processed food strongly depend on their packaging and the protection that it provides. The increasing accumulation of synthetic non-biodegradable plastics in the environment represents a threat to the natural habitats. This has lead companies and researchers to explore different ways to develop bio-based polymers made from a variety of agricultural commodities and/or food waste products. Recently, plant-based polysaccharides such as hemicelluloses and celluloses have attracted attention as replacements for petroleum-based materials. In this context, the cell wall composition determines the quality of most plant-based products used in modern human societies. Nutritional and processing properties of plant-based foods are heavily influenced by wall properties. Fibres for textiles, paper manufacture, timber products and now, for fuel and bio-composites manufacture, are largely composed of, or derived from, walls. As the largest source of renewable carbon, plant cell walls have a critical future role in providing transport fuels, food security, functional foods to improve human health, and as raw materials for industrial processes. The use of cellulose materials as polysaccharides source offers the possibility of obtaining new advanced biomaterials for fresh or processed foods sustainability. In this review, the cell wall metabolism, extraction and hydrolyzation of polysaccharides in different microorganisms and plants, and their application for the development of new carbohydrate-based advanced biomaterials that can be applied for the food industry are reported.
Synthesis and Characterization of Zirconium-Resorcinol Phosphate; A New Hybrid Cation Exchanger and Dye Adsorbent for Water Treatment
Authors: Fathima Syeed Zeeshaan , Pandith Altaf Hussain
Published: February 2016

Synthesis and characterization of a new hybrid ion exchange material Zirconiumresorcinol Phosphate (ZrRP) is reported in this study. Synthetic conditions such as reactant concentrations and mixing volume ratio were varied to optimize the ion exchange properties of this material. The material has Na+ ion exchange capacity equal to 1.7 meq/g (dry). X-ray diffraction spectra suggest that it is amorphous in nature. This ion-exchanger was also characterization by SEM, IR and TGA-DTG. Various studies such as determination of ion exchange capacity, elution behaviour and pH titration has been performed for different metal ions such as K+, Ca2+, Sr2+, Mg2+, Ni2+, Cd2+. This material has potential application for removal of these ions from the aqueous systems. Effect of anionic (SDS) and nonionic (TX-100) surfactants has also been studied on the adsorption behavior of ZrRP. The material has been found to be selective for Mg2+and Cd2+. We also found that the material showed remarkable adsorption behavior towards some dyes like malachite green and methylene blue.
An M1-like Macrophage Polarization in Decidual Tissue during Spontaneous Preterm Labor That Is Attenuated by Rosiglitazone Treatment
Authors: Xu Yi , Romero Roberto , Miller Derek , Kadam Leena , Mial Tara N. , Plazyo Olesya , Garcia-Flores Valeria , Hassan Sonia S. , Xu Zhonghui , Tarca Adi L. , Drewlo Sascha , Gomez-Lopez Nardhy
Published: February 2016

Decidual macrophages are implicated in the local inflammatory response that accompanies spontaneous preterm labor/birth; however, their role is poorly understood. We hypothesized that decidual macrophages undergo a proinflammatory (M1) polarization during spontaneous preterm labor and that PPARγ activation via rosiglitazone (RSG) would attenuate the macrophage-mediated inflammatory response, preventing preterm birth. In this study, we show that: 1) decidual macrophages undergo an M1-like polarization during spontaneous term and preterm labor; 2) anti-inflammatory (M2)-like macrophages are more abundant than M1-like macrophages in decidual tissue; 3) decidual M2-like macrophages are reduced in preterm pregnancies compared with term pregnancies, regardless of the presence of labor; 4) decidual macrophages express high levels of TNF and IL-12 but low levels of peroxisome proliferator–activated receptor γ (PPARγ) during spontaneous preterm labor; 5) decidual macrophages from women who underwent spontaneous preterm labor display plasticity by M1↔M2 polarization in vitro; 6) incubation with RSG reduces the expression of TNF and IL-12 in decidual macrophages from women who underwent spontaneous preterm labor; and 7) treatment with RSG reduces the rate of LPS-induced preterm birth and improves neonatal outcomes by reducing the systemic proinflammatory response and downregulating mRNA and protein expression of NF-κB, TNF, and IL-10 in decidual and myometrial macrophages in C57BL/6J mice. In summary, we demonstrated that decidual M1-like macrophages are associated with spontaneous preterm labor and that PPARγ activation via RSG can attenuate the macrophage-mediated proinflammatory response, preventing preterm birth and improving neonatal outcomes. These findings suggest that the PPARγ pathway is a new molecular target for future preventative strategies for spontaneous preterm labor/birth.