bluuebunny/crossref_metadata_2025 huggingface dataset:
ACCRETION AND ORBITAL INSPIRAL IN GAS-ASSISTED SUPERMASSIVE BLACK HOLE BINARY MERGERS
Authors: Rafikov Roman R.
Published: August 2016

Many galaxies are expected to harbor binary supermassive black holes (SMBHs) in their centers. Their interaction with the surrounding gas results in the accretion and exchange of angular momentum via tidal torques, facilitating binary inspiral. Here, we explore the non-trivial coupling between these two processes and analyze how the global properties of externally supplied circumbinary disks depend on the binary accretion rate. By formulating our results in terms of the angular momentum flux driven by internal stresses, we come up with a very simple classification of the possible global disk structures, which differ from the standard constant

accretion disk solution. The suppression of accretion by the binary tides, leading to a significant mass accumulation in the inner disk, accelerates binary inspiral. We show that once the disk region strongly perturbed by the viscously transmitted tidal torque exceeds the binary semimajor axis, the binary can merge in less than its mass-doubling time due to accretion. Thus, unlike the inspirals driven by stellar scattering, the gas-assisted merger can occur even if the binary is embedded in a relatively low-mass disk (lower than its own mass). This is important for resolving the “last parsec” problem for SMBH binaries and understanding powerful gravitational wave sources in the universe. We argue that the enhancement of accretion by the binary found in some recent simulations cannot persist for a long time and should not affect the long-term orbital inspiral. We also review existing simulations of SMBH binary–disk coupling and propose a numerical setup which is particularly well suited to verifying our theoretical predictions.
ON THE NATURE OF HYDROSTATIC EQUILIBRIUM IN GALAXY CLUSTERS
Authors: Biffi V. , Borgani S. , Murante G. , Rasia E. , Planelles S. , Granato G. L. , Ragone-Figueroa C. , Beck A. M. , Gaspari M. , Dolag K.
Published: August 2016

In this paper, we investigate the level of hydrostatic equilibrium (HE) in the intracluster medium of simulated galaxy clusters, extracted from state-of-the-art cosmological hydrodynamical simulations performed with the Smoothed-Particle-Hydrodynamic code GADGET-3. These simulations include several physical processes, among which are stellar and active galactic nucleus feedback, and have been performed with an improved version of the code that allows for a better description of hydrodynamical instabilities and gas mixing processes. Evaluating the radial balance between the gravitational and hydrodynamical forces via the gas accelerations generated, we effectively examine the level of HE in every object of the sample and its dependence on the radial distance from the center and on the classification of the cluster in terms of either cool-coreness or dynamical state. We find an average deviation of 10%–20% out to the virial radius, with no evident distinction between cool-core and non-cool-core clusters. Instead, we observe a clear separation between regular and disturbed systems, with a more significant deviation from HE for the disturbed objects. The investigation of the bias between the hydrostatic estimate and the total gravitating mass indicates that, on average, this traces the deviation from HE very well, even though individual cases show a more complex picture. Typically, in the radial ranges where mass bias and deviation from HE are substantially different, the gas is characterized by a significant amount of random motions (

), relative to thermal ones. As a general result, the HE-deviation and mass bias, at a given distance from the cluster center, are not very sensitive to the temperature inhomogeneities in the gas.
CANDIDATE WATER VAPOR LINES TO LOCATE THE H2O SNOWLINE THROUGH HIGH-DISPERSION SPECTROSCOPIC OBSERVATIONS. I. THE CASE OF A T TAURI STAR
Authors: Notsu Shota , Nomura Hideko , Ishimoto Daiki , Walsh Catherine , Honda Mitsuhiko , Hirota Tomoya , Millar T. J.
Published: August 2016

Inside the H2O snowline of protoplanetary disks, water evaporates from the dust-grain surface into the gas phase, whereas it is frozen out onto the dust in the cold region beyond the snowline. H2O ice enhances the solid material in the cold outer part of a disk, which promotes the formation of gas-giant planet cores. We can regard the H2O snowline as the surface that divides the regions between rocky and gaseous giant planet formation. Thus observationally measuring the location of the H2O snowline is crucial for understanding the planetesimal and planet formation processes, and the origin of water on Earth. In this paper, we find candidate water lines to locate the H2O snowline through future high-dispersion spectroscopic observations. First, we calculate the chemical composition of the disk and investigate the abundance distributions of H2O gas and ice, and the position of the H2O snowline. We confirm that the abundance of H2O gas is high not only in the hot midplane region inside the H2O snowline but also in the hot surface layer of the outer disk. Second, we calculate the H2O line profiles and identify those H2O lines that are promising for locating the H2O snowline: the identified lines are those that have small Einstein A coefficients and high upper state energies. The wavelengths of the candidate H2O lines range from mid-infrared to sub-millimeter, and they overlap with the regions accessible to the Atacama Large Millimeter/sub-millimeter Array and future mid-infrared high-dispersion spectrographs (e.g., TMT/MICHI, SPICA).
PROSPECTS FOR CONSTRAINING THE SPIN OF THE MASSIVE BLACK HOLE AT THE GALACTIC CENTER VIA THE RELATIVISTIC MOTION OF A SURROUNDING STAR
Authors: Yu Qingjuan , Zhang Fupeng , Lu Youjun
Published: August 2016

In this paper, we investigate the quality of constraining the spin of the massive black hole (MBH) at the Galactic center (GC) by using full general relativistic simulations of the motion of a surrounding star. We obtain the dependence mapping of the spin-induced signals on any spin direction of the MBH for given example stars, which indicates the feasibility to test whether the spin direction is the same as the normal of the young stellar disk located at the GC, and, further, to provide insights into the assembly history of the MBH. We demonstrate the quality of constraining the MBH spin that may be achieved, given any set of the astrometric and the redshift precisions of observational facilities. We find that in the ranges of the astrometric and the velocity precisions with 1–30 μas and 0.1–10

, an improvement in astrometric precision would be more effective at improving the quality of constraining the spin than an improvement in velocity precision. We obtain the parameter space of the semimajor axis and the eccentricity for the orbit of the target star that a high-precision constraint on the GC MBH spin can be obtained via the motion of the star. Our results show that the spin of the GC MBH can be constrained with a 1σ error ≲0.1 or even ≲0.02 by monitoring the orbital motion of a star, if existing as expected, with a semimajor axis ≲300 au and eccentricity ≳0.95 over a period shorter than a decade through future facilities.
EVOLUTION OF THE MAGNETIC FIELD LINE DIFFUSION COEFFICIENT AND NON-GAUSSIAN STATISTICS
Authors: Snodin A. P. , Ruffolo D. , Matthaeus W. H.
Published: August 2016

The magnetic field line random walk (FLRW) plays an important role in the transport of energy and particles in turbulent plasmas. For magnetic fluctuations that are transverse or almost transverse to a large-scale mean magnetic field, theories describing the FLRW usually predict asymptotic diffusion of magnetic field lines perpendicular to the mean field. Such theories often depend on the assumption that one can relate the Lagrangian and Eulerian statistics of the magnetic field via Corrsin’s hypothesis, and additionally take the distribution of magnetic field line displacements to be Gaussian. Here we take an ordinary differential equation (ODE) model with these underlying assumptions and test how well it describes the evolution of the magnetic field line diffusion coefficient in 2D+slab magnetic turbulence, by comparisons to computer simulations that do not involve such assumptions. In addition, we directly test the accuracy of the Corrsin approximation to the Lagrangian correlation. Over much of the studied parameter space we find that the ODE model is in fairly good agreement with computer simulations, in terms of both the evolution and asymptotic values of the diffusion coefficient. When there is poor agreement, we show that this can be largely attributed to the failure of Corrsin’s hypothesis rather than the assumption of Gaussian statistics of field line displacements. The degree of non-Gaussianity, which we measure in terms of the kurtosis, appears to be an indicator of how well Corrsin’s approximation works.
MEASUREMENT OF THE INTEGRATED SACHS–WOLFE EFFECT USING THE ALLWISE DATA RELEASE
Authors: Shajib Anowar J. , Wright Edward L.
Published: August 2016

One of the physical features of a dark-energy-dominated universe is the integrated Sachs–Wolfe (ISW) effect on the cosmic microwave background (CMB) radiation, which gives us a direct observational window to detect and study dark energy. The AllWISE data release of the Wide-field Infrared Survey Explorer (WISE) has a large number of point sources which span a wide redshift range, including where the ISW effect is maximized. AllWISE data are thus very well-suited for the ISW effect studies. In this study, we cross-correlate AllWISE galaxy and active galactic nucleus (AGN) overdensities with the Wilkinson Microwave Anisotropy Probe CMB temperature maps to detect the ISW effect signal. We calibrate the biases for galaxies and AGNs by cross-correlating the galaxy and AGN overdensities with the Planck lensing convergence map. We measure the ISW effect signal amplitudes relative to the ΛCDM expectation of A = 1 to be

for galaxies and

for AGNs. The detection significances for the ISW effect signal are

and

for galaxies and AGNs, respectively, providing a combined significance of

. Our result is in agreement with the ΛCDM model.
ANALYTICAL INVESTIGATION OF THE DECREASE IN THE SIZE OF THE HABITABLE ZONE DUE TO A LIMITED CO2 OUTGASSING RATE
Authors: Abbot Dorian S.
Published: August 2016

The habitable zone concept is important because it focuses the scientific search for extraterrestrial life and aids the planning of future telescopes. Recent work has shown that planets near the outer edge of the habitable zone might not actually be able to stay warm and habitable if CO2 outgassing rates are not large enough to maintain high CO2 partial pressures against removal by silicate weathering. In this paper, I use simple equations for the climate and CO2 budget of a planet in the habitable zone that can capture the qualitative behavior of the system. With these equations I derive an analytical formula for an effective outer edge of the habitable zone, including limitations imposed by the CO2 outgassing rate. I then show that climate cycles between a snowball state and a warm climate are only possible beyond this limit if the weathering rate in the snowball climate is smaller than the CO2 outgassing rate (otherwise stable snowball states result). I derive an analytical solution for the climate cycles including a formula for their period in this limit. This work allows us to explore the qualitative effects of weathering processes on the effective outer edge of the habitable zone, which is important because weathering parameterizations are uncertain.
SPECTRAL INTENSITIES OF ANTIPROTONS AND THE NESTED LEAKY-BOX MODEL FOR COSMIC RAYS IN THE GALAXY
Authors: Cowsik R. , Madziwa-Nussinov T.
Published: August 2016

In this paper we note that the spectral intensities of antiprotons observed in Galactic cosmic rays in the energy range ∼1–300 GeV by BESS, PAMELA, and AMS instruments display nearly the same spectral shape as that generated by primary cosmic rays through their interaction with matter in the interstellar medium, without any significant modifications. More importantly, a constant residence time of ∼2.3 ± 0.7 million years in the Galactic volume, independent of the energy of cosmic rays, matches the observed intensities. A small additional component of secondary antiprotons in the energy range below 10 GeV, generated in cocoon-like regions surrounding the cosmic-ray sources, seems to be present. We discuss this result in the context of observations of other secondary components such as positrons and boron, and the bounds on anisotropy of cosmic rays. In the nested leaky-box model the spectral intensities of antiprotons and positrons can be interpreted as secondary products of cosmic-ray interactions.
Melanocytic Nevi in Children: A Review
Authors: Levy Rebecca , Lara-Corrales Irene
Published: August 2016

Common moles on the skin, known scientifically as melanocytic nevi, are seen frequently in the pediatric population. They are broadly grouped into two groups: congenital (generally present at birth or in infancy) or acquired. Congenital melanocytic nevi (CMN) are classified based on size and morphologic features. Neurocutaneous melanosis and melanoma represent two important complications, with overall risk affected by nevus size, location, appearance, and number of satellite lesions. Regular lifelong skin surveillance is required for high-risk CMN. Acquired melanocytic nevi (AMN) tend to appear in childhood and increase in number through adolescence. Risk factors for melanoma in children with moles include having more than 50 AMN, clinically atypical AMN, family history of melanoma, excessive ultraviolet light exposure, lightly pigmented skin, and immunosuppression. Children with risk factors should be monitored regularly. The periodic health examination presents an opportunity to perform total body skin examination to screen for concerning lesions and to provide anticipatory guidance about sun protection.

[
Pediatr Ann
. 2016;45(8):e293–e298.]
Vascular Lesions
Authors: Jahnke Marla N.
Published: August 2016

Vascular lesions in childhood are comprised of vascular tumors and vascular malformations. Vascular tumors encompass neoplasms of the vascular system, of which infantile hemangiomas (IHs) are the most common. Vascular malformations, on the other hand, consist of lesions due to anomalous development of the vascular system, including the capillary, venous, arterial, and lymphatic systems. Capillary malformations represent the most frequent type of vascular malformation. IHs and vascular malformations tend to follow relatively predictable growth patterns in that IHs grow then involute during early childhood, whereas vascular malformations tend to exhibit little change. Both vascular tumors and vascular malformations can demonstrate a wide range of severity and potential associated complications necessitating specialist intervention when appropriate. Evaluation and treatment of the most common types of vascular lesions are discussed in this article.

[
Pediatr Ann
. 2016;45(8):e299–e305.]
Innocent Heart Murmurs from the Perspective of the Pediatrician
Authors: Mesropyan Levon , Sanil Yamuna
Published: August 2016

Innocent heart murmurs are quite common in children and adolescents. These murmurs are physiologic in nature and are not associated with any structural heart disease. Not only does the idea of having a child with a murmur bring unnecessary unrest to families, but the child also often goes through numerous tests that could be avoided. It is critical to obtain a detailed history and perform a thorough physical examination to diagnose these innocent murmurs. This article reviews the different types of innocent murmurs, their characteristics, how they can be differentiated on the physical examination, and most importantly, how they can be differentiated from pathologic murmurs, which require referral to a pediatric cardiologist and additional testing.

[
Pediatr Ann
. 2016;45(8):e306–e309.]
El negocio del siglo. Los judeoconversos y la renta de la seda del Reino de Granada (siglo XVI)
Authors: Soria Mesa Enrique
Published: August 2016

La renta de la seda de Granada fue uno de los principales impuestos españoles durante la Época Moderna. La investigación en que se basa este artículo demuestra que la gran mayoría de los arrendadores de impuestos que encontramos en su gestión fueron parientes cercanos entre sí. Además, todos ellos fueron judeoconversos que no sólo se enriquecieron con esta actividad económica, sino que la utilizaron para progresar socialmente.
Finite Element Analysis of Pipe Bends under External Loads
Authors: S. Sumesh , Veerappan A. R. , Shanmugam S.
Published: August 2016

Pipelines are being used to convey different sorts of fluids from hazardous and toxic substances to high pressure steam. Piping systems are subjected to various external loads leading to major failures with gross plastic deformation. Pipe bends are incorporated into piping systems not only to change the direction of flow but also to provide flexibility, hence they are considered to be critical components and its safe design under various loads becomes important. Earlier studies of pipe bends utilized analytical methods to determine the plastic loads. The evolution of FEM and the advancements in computational capabilities have enabled analysts to generate large number of data which is expensive and time consuming with experimental investigations. In this chapter, the major studies on pipe bends by various researchers are explored. Different studies on pipe bends namely stress analysis and the influence of geometric shape imperfections are also presented.
Fuzzy Structural Analysis Using Surrogate Models
Authors: Balu A. S. , Rao B. N.
Published: August 2016

The exponential growth of computational power during the last few decades has enabled the finite element analysis of many real-life engineering systems which are too complex to be analytically solved in a closed form. In the traditional deterministic finite element analysis, system parameters such as mass, geometry and material properties are assumed to be known precisely and defined exactly. However, in practice most of the data used in the solution process of many practical engineering systems are either collected from experiments or acquired as empirical data from the past, which are usually ill defined, imprecise and uncertain in nature. This work presents a practical approach based on High Dimensional Model Representation (HDMR) for analyzing the response of structures with fuzzy parameters. The proposed methodology involves integrated finite element modelling, HDMR based surrogate model, and explicit fuzzy analysis procedures.
Application of Conventional Data Mining Techniques and Web Mining to Aid Disaster Management
Authors: Kumar Akshay , Mukherjee Alok Bhushan , Krishna Akhouri Pramod
Published: August 2016

Data mining techniques have potential to unveil the complexity of an event and yields knowledge that can create a difference. They can be employed to investigate natural phenomena; since these events are complex in nature and are difficult to characterize as there are elements of uncertainty involved in their functionality. Therefore, techniques that are compatible with uncertain elements can be employed to study them. This chapter explains the concepts of data mining and discusses at length about the landslide event. Further, the utility of data mining techniques in disaster management using a previous work was explained and provides a brief note on the efficiency of web mining in creating awareness about natural hazard by providing refined information. Finally, a conceptual framework for landslide hazard assessment using data mining techniques such as Artificial Neural Network (ANN), Fuzzy Geometric Mean Model (FGMM), etc. were chosen for description. It was quite clear from the study that data mining techniques are useful in assessing and modelling different aspects of landslide event.
A Dynamic and Scalable Decision Tree Based Mining of Educational Data
Authors: Vaghela Dineshkumar B. , Sharma Priyanka , Passi Kalpdrum
Published: August 2016

The explosive growth in the amount of data in the field of biology, education, environmental research, sensor network, stock market, weather forecasting and many more due to vast use of internet in distributed environment has generated an urgent need for new techniques and tools that can intelligently automatically transform the processed data into useful information and knowledge. Hence data mining has become a research are with increasing importance. Since continuation in collection of more data at this scale, formalizing the process of big data analysis will become paramount. Given the vast amount of data are geographically spread across the globe, this means a very large number of models is generated, which raises problems on how to generalize knowledge in order to have a global view of the phenomena across the organization. This is applicable to web-based educational data. In this chapter, the new dynamic and scalable data mining approach has been discussed with educational data.
Methodologies and Techniques of Web Usage Mining
Authors: Rao T. Venkat Narayana , Hiranmayi D.
Published: August 2016

Web usage mining attempts to discover useful knowledge from the secondary data obtained from the interactions of the users with the Web. It is the type of Web mining activity that involves the automatic discovery of out what users are looking for on the Internet. In this chapter methodology of web usage mining explained in detail which are data collection, data preprocessing, knowledge discovery and pattern analysis. The different Web Usage Mining techniques are described, which are used for knowledge and pattern discovery. These are statistical analysis, sequential patterns, classification, association rule mining, clustering, dependency modeling. Pattern analysis is needed to filter out uninterested rules or patterns from the set found in the pattern discovery phase.
Success Dimensions of ICTs in Healthcare
Authors: Kaur Pankaj Deep , Sharma Pallavi
Published: August 2016

During the last decades, the call for Information and Communication Technologies (ICTs) in healthcare has been augmented to endow with healthcare services at a global scale and to trim down medical errors that cost human lives. Enriched with explosive computing and high communicating power, ICTs like Internet, mobile telephony, and other enabled gadgets plays a prominent role in our day-to-day activities. With the potential to provide access to service for patients in difficult-to reach areas and facilitating medical record keeping and information sharing are the main considerations of leveraging ICTs in realm of clinical care. The insurgence of these innovating technologies into healthcare sectors is not only blurring the boundaries for the emergence of other new technologies but also causing a paradigm shift in providing acute and preventative care in public health. The main goal of this chapter is to offer readers an insight into how the emergence of ICTs have transformed healthcare sector by delivering cost-efficient and quality of care to patients.
Analysis of Electrocardiogram Data Compression Techniques
Authors: Pandey Anukul , Saini Barjinder Singh , Singh Butta , Sood Neetu
Published: August 2016

In this Chapter, a MATLAB-based approach is presented for compression of Electrocardiogram (ECG) data. The methodology employs in three different domains namely direct, transformed and parameter extraction methods. The selected techniques from direct ECG compression methods are TP, AZTEC, Fan, and Cortes. Moreover selected techniques from transformed ECG compression methods are Walsh Transform, DCT, and Wavelet transform. For each of the technique, the basic implementation of the algorithm was explored, and performance measures were calculated. All 48 records of MIT-BIH arrhythmia ECG database were employed for performance evaluation of various implemented techniques. Moreover, based on requirements, any basic techniques can be selected for further innovative processing that may include the lossless encoding.
An Analysis of a Lay Adjudication System and Open Judiciary
Authors: Kita Yumiko
Published: August 2016

This paper presents analyses of impacts of lay adjudicators' participation in criminal matters in Japan due to the introduction of the new lay adjudication system – the Citizen Judge System [Saiban-in Seido] – in 2009. Since the late twentieth century, the introduction of the lay adjudication system seems to have been in international movement democratising the criminal justice system. This paper is devoted to an evaluation of the new system in terms of the balance between the concepts of democracy and a fair trial with consideration of the citizen judge procedures and the role of the citizen judges. In view of the closed nature of the Japanese criminal procedures and secrecy in the citizen judge system, this study will point out the challenges which prevent the fulfilment of democratic values in the practice of the citizen judge system.
Consumer “Access to Justice” in EU in Low-Value Cross-Border Disputes and the Role of Online Dispute Resolution
Authors: Barral-Viñals Inmaculada
Published: August 2016

This paper examines consumer access to justice in the EU by analysing how Alternative Dispute Resolution (ADR) and Online Dispute Resolution (ODR) can improve this access, especially in the case of low-value cross-border disputes, which constitute the majority of consumer contract complaints. The discussion is based on a widened concept of open justice that not only seeks to provide greater transparency, but also greater participation and collaboration as a means to improve consumer access to justice. The approach deals with the subjective and objective obstacles to accessing justice and the role of participatory justice. Finally, the paper examines the decisions taken by the EU in its attempt to foster both ADRs and ODRs for consumer disputes and determines which obstacles have been eliminated in promoting access to justice.
East vs. West Approaches to Reporting Corporate Sustainability Strategies to the World
Authors: Kaplan Jensena , Montiel Ivan
Published: August 2016

This chapter applies Hofstede's cultural dimensions to compare how companies located in Western and Eastern regions present their corporate sustainability strategies to their stakeholders. We compare ten pairs of West-East companies and find that differences in the corporate sustainability strategies they report can be related to geo-political and socio-cultural differences as described by Hofstede. Our findings can serve as a tool for companies in both regions to gain a better understanding about which sustainability initiatives are of more concern, depending on the region they operate.
An Evaluation of the State of the CSR Field in Australia
Authors: de Burgh-Woodman Hélène , Bressan Alessandro , Torrisi Angela
Published: August 2016

While Corporate Social Responsibility (CSR) has become established in the managerial lexicon, its meaning and application varies according to geographical and sector contexts. In this chapter, we focus on the application of CSR across the banking and mining sectors in Australia to analyse the ways in which this managerial mechanism, with its theoretical underpinnings of social, environmental and economic balance, has been strategically appropriated and applied. We pose the key questions of how has CSR been implemented in Australia's largest industries and, secondarily, why has CSR not been more effective in transforming business practice in Australia? To demonstrate the alternative purposes to which CSR has been put, we use two case studies drawn from Australia's two most visible industries. The purpose of these case studies is to illustrate the larger conceptual ambiguity or fragmentation endemic to CSR and how this ambiguity affects its application – and therefore effectiveness – across different contexts.
Doing Good Doing Well
Authors: Hack-Polay Dieu , Qiu Haiyan
Published: August 2016

Corporate social responsibility (CSR) involves multi-faceted concerns and interested parties. The theoretical paper argues that pursuing CSR policies creates value for sustainable economic prosperity for the pulp and paper sector. The pulp and paper industry is one of the largest industrial sectors worldwide and plays a critical role in global development. As the fourth largest energy user and CO2 emitter, the industry is subject to the vicissitudes of global society and environment. Irresponsible pulp and paper operations are now shunned by various stakeholders, which ultimately affect their economic bottom lines. Sustainable operations bring continuity and competitiveness along with innovation, efficiency and social recognition to the industry. Using the criteria of the triple-bottom-line theory (economic, environmental and social), this paper demonstrates that a strong CSR framework and proactive initiatives add value to the pulp and paper business.
Multi-Stakeholder Initiatives and Corporate Social Responsibility in Global Value Chains
Authors: Hassan Ahmad , Lund-Thomsen Peter
Published: August 2016

In this chapter, we make a contribution to the literature on corporate social responsibility in global value chains that link dispersed consumers and importers in developed countries with local manufacturers, workers, and communities in developing countries. We create an integrated analytical framework and a methodology that can guide master-level and Ph.D. students as well as practitioners on how they may map the governance processes through which multi-stakeholder initiatives (MSIs) in global value chains are formulated, implemented, monitored as well as the impact that MSI standards have on the work conditions of those laboring at the base of global value chains. We use a stylized case study of fair trade in the football manufacturing industry in Pakistan to illustrate how the framework and the methodology might be applied to the empirical analysis of MSI governance processes and their impacts on workers' conditions in export-oriented industries in the South.
Fatigue and Cyclic Behavior of 304L Stainless Steel in the Presence of Boriding Surface Treatment
Authors: Allaoui Omar , Taleb Lakhdar
Published: August 2016

In this work, we will study the cyclic behavior (tension-compression under strain control) and the fatigue of 304L austenitic SS after application of a boriding thermochemical treatment. 304L specimens was borided in a solid medium at 900 °C for 4 hours. The phase analysis of boride layers formed at the surface was performed by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD). The obtained results show that the layers formed on 304L steel contained the following boride phases FeB, Fe2B, CrB, Cr2B, NiB and Ni2B. The fatigue tests show that the boriding treatment improves the life a factor which may be greater than four. The borided specimens show a negative average stress during cycling which may explain the increase of fatigue life. Analysis of the fracture surface by SEM show that crack initiation takes place in the substrate rather than in the boron-treated area.
Effect of Pre-Deformation on the Cyclic Behavior and Fatigue of 304L SS
Authors: Taleb Lakhdar , Kpodekon Crescent
Published: August 2016

This study deals with the effect of the loading history on the cyclic behavior and the fatigue life of a 304L stainless steel at room temperature. The experiments have been performed using two specimens’ categories. The first one (virgin) has been submitted to only classical fatigue tests while in the second category, prior to the fatigue test; the specimen was subjected to a pre-hardening process under either monotonic or cyclic strain control. Cyclic softening followed by cyclic hardening are observed for the virgin specimens while only cyclic softening is exhibited by the pre-hardened specimens. The obtained results show that fatigue life is strongly influenced by the pre-hardening: the latter seems beneficial under stress control but detrimental under strain control, even in the presence of a compressive mean stress. The results are discussed regarding the cyclic evolution of the elastic modulus as well as the isotropic and kinematic parts of the strain hardening in different configurations: with or without pre-hardening, stress or strain control.
Study of DP590 High-Strength Steel Sheet Cruciform Specimen for Biaxial Tensile
Authors: Lei Yu , Meng Zheng Hua , Huang Shang Yu , Hu Jian Hua , Zhou Meng Cheng , Dong Guo Xu
Published: August 2016

Several different DP590 high-strength steel sheet cruciform specimens were tested by biaxial tensile experiment system. According to the experimental results, an appropriate cruciform specimen could be used for biaxial tensile pre-strain was selected to be optimized. The effects of the number and location of slits were discussed through ANSYS software numerical analysis. The biaxial tensile properties of DP590 high-strength steel sheet were obtained by the biaxial tensile test system. The results show that the uniform deformation area of the cruciform specimen center is about 80%, and the maximum biaxial tensile pre-strain is nearly 3.14%.
Analyses about the Anisotropic Behavior of a 2017A Aluminum Alloy
Authors: Brik Mouaad , Chabane Chaouche Malek , Taleb Lakhdar
Published: August 2016

The study presented in this paper uses a multi-mechanism model (MM) in order to simulate the cyclic behavior of an anisotropic aluminum alloy 2017A subjected to complex loading. Two sets of parameters were used. The first set is proposed in [1]; it is identified considering cyclic tests performed under strain control following proportional and non-proportional paths. The second set of parameters has been identified recently on a larger database [2]. In this work, we propose to evaluate the capability of the according to the set of parameters under consideration. Note that the identification process in both cases was performed using strain controlled experiments while the evaluation of the model uses stress controlled experiments.
Investigation of Structural, Optical an Electrical Characterization of AZO Films Used for Solar Cells
Authors: Song Chao , Lin Zhen Xu , Zhang Yi , Wang Xiang , Guo Yan Qing , Song Jie , Huang Rui
Published: August 2016

Transparent conductive Al-doped ZnO (AZO) thin films used as transparent conductive oxide (TCO) electrode layers for thin film solar cells were deposited on quartz substrate by radio frequency (RF) magnetron sputtering. After deposition, the samples were annealed at various temperatures. The structural, electrical, and optical properties of these films have been analyzed as a function of the annealing temperature. All of these samples exhibit strong (002) diffraction peaks and the average transmittance in visible range is about 85%. The crystallinity of films together with some changes of the electrical resistance has been improved after thermal annealing. The best characteristics have been obtained at 400 °C, where the lowest resistivity is 2.4×10-3 Ω cm and the optical band gap is 3.22 eV.
Design of Complex Component for Determination of a CNC Milling Machines Accuracy
Authors: Moravčíková Jana , Pokorný Peter
Published: August 2016

The article is focused on the design of complex component to determine competence CNC milling machines designed to produce shapes with geometric tolerances by observing the shape, orientation and position of the standard EN ISO 1101. 3D model of a technological process for the production of complex components, it will contain the complete design of tools and cutting parameters for individual milling strategy, select clamping and workpiece material, a preview of the generated routing strategies and paths cut surface after each of their simulated. For milling machines with the so-called measurement system for machine OMM (On Machine Measurement), the proposal for a comprehensive parts serve as a reference in determining the accuracy of their measurements of geometric and dimensional tolerances. The main activity of systems OMM is the replace of the tool clamped in the spindle of milling machines with special touch probe which senses by the touch surface contours of produced parts.
The Effect of Substrate Surface Condition on Atomic Layer Deposited Alumina Passivation Films
Authors: Xiang Yu Ren , Zhou Chun Lan , Wang Wen Jing
Published: August 2016

Aluminum oxide (Al2O3) films have been wildly investigated due to the excellent surface passivation for the electrical device. Both hydrogen-terminated and pre-oxidized silicon surfaces were prepared before Al2O3 films deposition. Combining chemical environment analysis with the effective minority lifetime data, the effect of the surface conditions on the Al2O3 films passivation was discussed. The HF sample with hydrogen-terminated substrate surface had a higher minority carrier lifetime (about 721 μs) than the H2SO4+H2O2 sample with pre-oxidized substrate surface (about 631 μs). The H atoms played an important role in improving the passivation effect. And the importance of the interfacial oxide layer to Al2O3 films passivation was validated too.
Morphology Control and Upconversion Enhancement in NaYF4:Yb3+,Er3+ Crystals via Ca2+ Ions Doping
Authors: Wang Min , Wu Jing , Chen Zhong Sheng
Published: August 2016

Pure hexagonal NaYF4:Yb3+,Er3+ crystals via doping with Ca2+ ions have been successfully prepared by a facile hydrothermal method. The morphology of the crystals was changed from microrods to microprisms. The upconversion (UC) luminescence properties of the as-prepared samples were investigated in detail.
The Influence of Geology Factor on Alkaline Surfactant Polymer Flood Effect and the Corresponding Strategy
Authors: Ye Peng , Zhang Dong , Zhong Lian Bin , Wang Guang , Fu Bin , Jin Hong Guang
Published: August 2016

This study gives the influence laws of abandoned channel, in-layer interlayer, sand body contact relationship on the development effect of the Alkaline Surfactant Polymer (ASP) flooding based on the data of the industry promotion block ( Pu I32、Pu I33 sedimentation), and give out corresponding adjustment strategy at the same time. The result shows that: The ‘abruptly abandoned’ channels have a bad connection with the main channel and possesses a far lower reservoir producing degree (16.1%) than the ‘gradually-abandoned’ channels (79.9%). The injection wells located upon the channel sand need high concentration inject fluid with lower injection rate to handle the polymer breakthrough; The injection wells located between the channels need lower concentration injection; The injection wells located upon the abandoned channels firstly need high concentration injection to achieve the profile control and then inject low concentration fluid to adjust low permeable sublayer; The production wells located upon abandoned channels need timely fracturing measures.
By July 2014, water content of this area is 90.7%, oil recovery improved 18.08% and is expected to reach 22.0%. Similar the success experience we get from this area can guide the study of block geologic factors that affect development result and has important guiding significance to the implementation of pointed development adjustment.
Structure and Properties of Dyes in Coloration of Textiles: Application of Fragment Approach
Authors: Telegin Felix Y. , Ran Jian Hua , Morshed Mainul , Pervez Md. Nahid , Sun Li , Zhang Cong , Priazhinikova Viktoriia G.
Published: August 2016

The paper reports the results of QSPR analysis of several problems of coloration of textiles, including light fastness of azo benzothiazole and indigoid dyes, ionization of hydroxyl groups in mordant dyes forming complexes with polyvalent metal ions and rate reactions of organic substances with OH radical during catalytic oxidizing of pollutants. Multiple linear regression models are built with the use of fragment descriptors. The role of different molecular fragments is discussed emphasizing the mechanism of the phenomena and ways of application in coloration technology.
One-Pot, Low-Temperature Preparation of Pyrochlore-Like Na2Ta2O6 Nanocrystals by Solvothermal Synthesis
Authors: Jiang Qing Song , Gao Jian , Yuan Hai Feng , Ding Lu Rong , Yi Lin
Published: August 2016

In this paper, pyrochlore-like Na2Ta2O6 nanocrystals have been successfully synthesized in mixed solvents (water-ethanol) by a single-step and low-temperature solvothermal method. During the synthesis process, tantalum chloride and sodium hydroxide are used as starting materials; diethanolamine is acted as a stabilizer. The influence of alkaline concentration, reaction temperature and time on the crystallinity and morphology of Na2Ta2O6 nanocrystals is investigated in detail. The samples are characterized by X-ray diffraction and transmission electron microscope. The results show that the pure-phase pyrochlore-like Na2Ta2O6 nanocrystals can be formed with 10.5 mmol sodium hydroxide at 353K for 12 h.
Online Prediction and Verification of Cured Quality of Advanced Composites in Autoclave Process
Authors: Zhang Yong An , Zhan Li Hua
Published: August 2016

The strain in curing process of composite part would be influenced by curing compaction, resin flow, curing action and tool-part interaction, meanwhile these factors would also influence the final cured quality of composite part. In this paper, FBG(fiber Bragg grating) sensors are used to in-situ monitoring the strain of composite parts, which are cured in four different pressure situation by autoclave: 0.0Mpa,0.2Mpa,0.4Mpa,0.6MPa. by analyzing the strain change rule, the part quality is predicted, then the predictive result is compared with some verification method: measurement of part’s boundary dimension, ultrasonic phased array scanning, metallographic analysis. The result shows that, the prediction is consistent with verification, the in-situ monitoring method by using FBG sensor is available for predicting cured quality of composite parts accurately: increase curing pressure is benefit of part compaction, resin flow, and reduce delamination,pores in composite part, finally improving the part quality dramatically.
Compound Mutation Breeding of Streptococcus equi JC-63 for Producing High Molecular Weight Hyaluronic Acid and Optimization of Culture Conditions
Authors: Zhang Rong Hu , Feng Jian Cheng
Published: August 2016

A strain of mutant Streptococcus equi JC-63, which can produce high molecular weight hyaluronic acid, was obtained from compound mutation breeding of Streptococcus equi JC-0 using 5-Bromouracil, UV rays and nitrosoguanidine as mutagenic agents. After inoculation for 25 generations, Streptococcus equi JC-63 showed inheritance stability, but not hemolysis. The culture conditions for producing HMW-HA were optimized in a 1-L shake flask through multi-factor orthogonal tests. Results showed the optimum ratio of fermentation medium comprised 50 g/L sucrose, 80 g/L corn steep liquor, 10 g/L glucose, 2 g/L MgSO4, 2 g/L NaHCO3, 2 g/L Na2HPO4, and 0.1 g/L UTP. Under these fermentation conditions, the molecular weight of the produced HA was 2.76 × 106 Da, and HA yield reached 4.12 g/L.
Machining and Characterization of Deep Micro Holes on Super Alloy Processed by Millisecond Pulsed Laser
Authors: Wang Yun Long , Zhu Lin Zhong , Chen Cai Yan , Liu Zhi Chen , Ren Wei Xin , Wang Liang
Published: August 2016

In this study, a series of deep micro holes were machined on thick GH4169 super alloy by the trepan drilling, using a millisecond pulsed laser which equipped to the numerical control processing system. The microstructure of the holes including surface and longitudinal morphologies, diameter, taper, circularity, micro cracks and recast layer were systematically characterized. The surface morphology and the longitudinal section of the drilled holes were observed by Scanning Electron Microscope and 3D Laser Scanning Confocal Microscope. The method of Minimum circumcircle method was employed to evaluate the entrance and exit end circularity. The results showed that the melt and spattering accumulating around the holes decreased with the augment of laser power. The diameter of the entrance showed an increasing tendency with the growing of laser power, but the exit end was not seriously affected by the power. The micro cracks and recast layer could be found obviously, the micro cracks appeared in those zones which thermal stress concentrated, the thickness of recast layer is about 20μm and the taper and circularity were optimized at a laser power of 80-100W.
Effect of Nano-CaCO3/Limestone Powder Composite on the Early Age Cement Hydration Products
Authors: Yang Hua Shan , Che Yu Jun , Zhang Man
Published: August 2016

In this study, the effect of surface structure of nanoCaCO3/limestone powder composite particles (NC/LS) on the hydration products of cement at early age is investigated. The surface structure of NC/LS is observed by field emission scanning electron microscope (FE-SEM) and compared with original limestone powders. X-ray diffraction (XRD) is used to investigate the types of hydration products and calculate the Ca (OH)2 (CH) particle size and crystal orientation degree. Additionally, FE-SEM and atomic force microscopy (AFM) are applied to observe the particle size, shape and distribution of hydration products. The results reveal that the nanoCaCO3 particles are distributed throughout the surface of limestone powders, and therefore successfully formed NC/LS. Secondly, the particle size, morphology and distribution of the cement hydration products are affected by the surface structure of NC/LS, so the microstructure of hardened cement paste at early age is enhanced.
Study on the Effect of Condensate-Type and Copolymer-Type Combined Superplasticizers on Hydration of Cement
Authors: Pan Yun Feng , Jiang Ya Qing , Zhang Si Jia
Published: August 2016

For the limitation of single-component superplasticizer, condensate-type and copolymer-type combined superplasticizers were prepared. The adsorption of compound superplasticizers on cement paste was tested by Total Organic Carbon (TOC) measurement. Influences of superplasticizers on early hydration process of cement and Organo-mineral phase formation were studied by X-Ray Diffraction Analysis (XRD), Scanning Electron Microscope analysis (SEM) and so on. The results show that owing to the electrostatic repulsion and steric effect cooperative mechanism, condensate-type and copolymer-type combined superplasticizers reduce the superplasticizers adsorption in cement minerals and its hydration products surface, delay the process of hydration of C3A, form Organic-Layered double hydroxides (LDH), increase the early chemical shrinkage and promote the growth of cement early hydration and Ettringite
Test Study on the Compressive Strength Properties of Compacted Clayey Soil
Authors: Liu Han Bing , Zhang Hu Zhu , Wang Jing
Published: August 2016

In order to study the effect of water content, degree of compaction and stress state on bearing capacity of subgrade, the engineering compacted clayey soil was taken as the subject investigated, regulation of compressive strength changing with water content, degree of compaction and confining pressure were analyzed through triaxial compression test, and function relationships between compressive strength and water content, degree of compaction and stress state were fitted based on the test data. Results show that effects of water content, degree of compaction and confining pressure on compressive strength properties of subgrade compacted clayey soil are all remarkably. The compressive strength decreases according to a quadratic function with the increase of water content, as well as increases in accordance with a quadratic function with the increase of the degree of compaction, and increases linearly with the increase of confining pressure. Improving the construction compaction standard properly, adopting the essential lateral confinement measure and keeping a lower water content of the subgrade in service can improve the bearing capacity and stability of the highway subgrade.