bluuebunny/crossref_metadata_2025 huggingface dataset:
Proper Motions of Sunspots’ Umbral Dots at High Temporal and Spatial Resolution
Authors: Goodarzi Hadis , Koutchmy Serge , Adjabshirizadeh Ali
Published: June 2018

To deepen the analysis of the photometric properties of the umbra of a sunspot, we study proper motions of small features such as umbral dots (UDs) inside a single sunspot observed by the Solar Optical Telescope of Hinode close to the disk center. We consider horizontal flows with high precision and details to study the transient motion behavior of UDs in short time intervals. Blue continuum images were first deconvolved with the point-spread function, such that the stray light is precisely removed and the original resolution is improved. Several images were co-added to improve the signal-to-noise ratio, keeping a reasonable temporal resolution and checking that the results are reproducible. The Fourier local correlation tracking technique is applied to the new corrected time sequence of images, and horizontal velocity maps were obtained both for the whole umbra (16″ × 12″) and for a high-resolution small region of the umbra (3.″5 × 3.″5) to study the smallest details of the velocity fields. We used two different Gaussian tracking windows (0.8 and 0.″2 ), which reveals two types of horizontal motions for umbral features. First, a global inner penumbra and peripheral umbra inward motion directed to the central parts is revealed as an overall proper motion of bright peripheral fine structures. Second, motions matching small cells inside the darkest parts of the umbra with apparent sink and source areas are revealed, suggesting possible upflows and downflows appearing in different bright and dark locations without a definite answer regarding their brightness identification with a convective or a buoyant cell.
A Systematic Spectral-timing Analysis of Kilohertz Quasi-periodic Oscillations in the Rossi X-Ray Timing Explorer Archive
Authors: Troyer Jon S. , Cackett Edward M. , Peille Philippe , Barret Didier
Published: June 2018

Kilohertz quasi-periodic oscillations or kHz QPOs occur on the orbital timescale of the inner accretion flow, and may carry signatures of the physics of strong gravity (c
2 ≃ GM/R) and possibly clues to constraining the neutron star equation of state. Both the timing behavior of kHz QPOs and the time-averaged spectra of these systems have been studied extensively, yet no model completely describes all the properties of kHz QPOs. Here, we present a systematic study of spectral-timing products of kHz QPOs from low-mass X-ray binary systems through the use of archival Rossi X-ray Timing Explorer/Proportional Counter Array data. For the lower kHz QPOs in 14 objects and the upper kHz QPOs in six objects, we were able to obtain correlated time lags as a function of QPO frequency and energy, as well as energy-dependent covariance spectra and intrinsic coherence. For the lower kHz QPOs, we find a monotonic decrease in lags with increasing energy, rising covariance to ∼12 keV, and near unity coherence at all energies. For the upper kHz QPOs, we find near zero lags, rising covariance to ∼12 keV, and less well-constrained coherence at all energies. These results suggest that while kHz QPOs are likely produced by similar mechanisms across the population of LMXBs, the lower kHz QPOs are likely produced by a different mechanism than the upper kHz QPOs.
The MALATANG Survey: The LGAS–LIR Correlation on Sub-kiloparsec Scale in Six Nearby Star-forming Galaxies as Traced by HCN J = 4 → 3 and HCO+ J = 4 → 3
Authors: Tan Qing-Hua , Gao Yu , Zhang Zhi-Yu , Greve Thomas R. , Jiang Xue-Jian , Wilson Christine D. , Yang Chen-Tao , Bemis Ashley , Chung Aeree , Matsushita Satoki , Shi Yong , Ao Yi-Ping , Brinks Elias , Currie Malcolm J. , Davis Timothy A. , Grijs Richard de , Ho Luis C. , Imanishi Masatoshi , Kohno Kotaro , Lee Bumhyun , Parsons Harriet , Rawlings Mark G. , Rigopoulou Dimitra , Rosolowsky Erik , Bulger Joanna , Chen Hao , Chapman Scott C. , Eden David , Gear Walter K. , Gu Qiu-Sheng , He Jin-Hua , Jiao Qian , Liu Dai-Zhong , Liu Li-Jie , Li Xiao-Hu , Michałowski Michał J. , Nguyen-Luong Quang , Qiu Jian-Jie , Smith Matthew W. L. , Violino Giulio , Wang Jian-Fa , Wang Jun-Feng , Wang Jun-Zhi , Yeh Sherry , Zhao Ying-He , Zhu Ming
Published: June 2018

We present

and

maps of six nearby star-forming galaxies, NGC 253, NGC 1068, IC 342, M82, M83, and NGC 6946, obtained with the James Clerk Maxwell Telescope as part of the MALATANG survey. All galaxies were mapped in the central 2′ × 2′ region at 14″ (FWHM) resolution (corresponding to linear scales of ∼0.2–1.0 kpc). The L
IR–L′dense relation, where the dense gas is traced by the

and the

emission, measured in our sample of spatially resolved galaxies is found to follow the linear correlation established globally in galaxies within the scatter. We find that the luminosity ratio, L
IR/L′dense, shows systematic variations with L
IR within individual spatially resolved galaxies, whereas the galaxy-integrated ratios vary little. A rising trend is also found between L
IR/L′dense ratio and the warm-dust temperature gauged by the 70 μm/100 μm flux ratio. We find that the luminosity ratios of IR/HCN (4–3) and IR/HCO+ (4–3), which can be taken as a proxy for the star formation efficiency (SFE) in the dense molecular gas (SFEdense), appear to be nearly independent of the dense gas fraction (f
dense) for our sample of galaxies. The SFE of the total molecular gas (SFEmol) is found to increase substantially with f
dense when combining our data with those on local (ultra)luminous infrared galaxies and high-z quasars. The mean

line ratio measured for the six targeted galaxies is 0.9 ± 0.6. No significant correlation is found for the

ratio with the star formation rate as traced by L
IR, nor with the warm-dust temperature, for the different populations of galaxies.
Cross-sectional Alignment of Polycyclic Aromatic Hydrocarbons by Anisotropic Radiation
Authors: Hoang Thiem , Lazarian A.
Published: June 2018

We study the effect of anisotropic radiation illumination on the alignment of polycyclic aromatic hydrocarbons (PAHs) and report that the cross-sectional mechanism of alignment earlier considered in terms of gas–grain interactions can also be efficient for the photon–grain interaction. We demonstrate this by first calculating the angle-dependence rotational damping and excitation coefficients by photon absorption followed by infrared emission. We then calculate the degree of PAH alignment for the different environments and physical parameters, including the illumination direction, ionization fraction, and magnetic field strength. For the reflection nebula (RN) conditions with unidirectional radiation field, we find that the degree of alignment tends to increase with increasing angle ψ between the illumination direction and the magnetic field, as a result of the decrease of the cross section of photon absorption with ψ. We calculate the polarization of spinning PAH emission using the obtained degree of alignment for the different physical parameters, assuming constant grain temperatures. We find that the polarization of spinning PAH emission from RNe can be large, between 5% and 20% at frequencies ν > 20 GHz, whereas the polarization is less than 3% for photodissociation regions. In realistic conditions, the polarization is expected to be lower owing to grain temperature fluctuations and magnetic field geometry. The polarization for the diffuse cold neutral medium is rather low, below 1% at ν > 20 GHz, consistent with observations by WMAP and Planck. Our results demonstrate that the RNe are the favored environment to observe the polarization of spinning dust emission and polarized mid-IR emission from PAHs.
Waves of Magnetic-field Variations Observed in a Flare-excited Sunquake Event
Authors: Zhao Junwei , Chen Ruizhu
Published: June 2018

We report on the detection of waves of magnetic-field variations that were associated with flare-excited sunquake waves. An X-9.3 flare that occurred on 2017 September 6 excited strong sunquakes, and the sunquake waves were observed sweeping across the flare’s host active region. This rare event gives us an unprecedented opportunity to study responses of magnetic field to passing sunquake waves. A wave of magnetic-field variations was observed in each of the two sunspots that the sunquake waves swept through, and the time–distance relations for the waves observed in magnetic field and Doppler velocity are similar. The phase relations measured between, as well as the oscillatory power distributions calculated from, the Doppler velocity variations and magnetic-field variations associated with the sunquake waves are compared with those obtained from the background waves in the same areas of the sunspot umbra and penumbra separately. The phase relations seem to favor the theory that the waves of magnetic variations are owing to opacity changes associated with the passing sunquake waves. The comparisons of phases and power distributions indicate that the background magnetic variations observed in sunspots are a combination of various wave modes, and fast magnetoacoustic waves only account for a fraction of those magnetic variations.
A NICER Spectrum of MAXI J1535–571: Near-maximal Black Hole Spin and Potential Disk Warping
Authors: Miller J. M. , Gendreau K. , Ludlam R. M. , Fabian A. C. , Altamirano D. , Arzoumanian Z. , Bult P. M. , Cackett E. M. , Homan J. , Kara E. , Neilsen J. , Remillard R. A. , Tombesi F.
Published: June 2018

We report on a Neutron star Interior Composition Explorer (NICER) observation of the Galactic X-ray binary and stellar-mass black hole candidate, MAXI J1535−571. The source was likely observed in an “intermediate” or “very high” state, with important contributions from both an accretion disk and hard X-ray corona. The 2.3–10 keV spectrum shows clear hallmarks of relativistic disk reflection. Fits with a suitable model strongly indicate a near-maximal spin parameter of

and a disk that extends close to the innermost stable circular orbit,

(1σ statistical errors). In addition to the relativistic spectrum from the innermost disk, a relatively narrow Fe K emission line is also required. The resolution of NICER reveals that the narrow line may be asymmetric, indicating a specific range of emission radii. Fits with a relativistic line model suggest an inner radius of

for the putative second reflection geometry; full reflection models suggest that radii a few times larger are possible. The origin of the narrow line is uncertain, but a warp likely provides the most physically plausible explanation. We discuss our results in terms of the potential for NICER to reveal new features of the inner and intermediate accretion disk around black holes.
Practical Tips for Facilitating Research in Clinical Nursing Practice
Authors: Kress Christine
Published: June 2018

Nursing research improves patient care, and clinical nurses have unique leadership perspectives regarding patient care and institutional needs. Clinical nurses involved in research are curious, are innovative, and implement the best practices. Many clinical nurses report lack of understanding of the research process, time, and institutional support as barriers to their involvement in research. This article presents practical strategies to encourage clinical nurses to develop and use research skills.

J Contin Educ Nurs.
2018;49(7):294–296.
A Qualitative Description of Nurses' Experiences With Incorporating Research Into Practice
Authors: Schuessler Zohreh , Castillo Leolin , Fessler Sheranda , Herrmann Robin , Kuntz Dora , Spencer Becky
Published: June 2018

Background:

Baccalaureate-prepared nurses should be competent in accessing, evaluating, and implementing research evidence into nursing practice. The purpose of this study was to gain insight into nurses' experiences in accessing, evaluating, and implementing research into practice.

Method:

Researchers conducted a qualitative descriptive study. Data were collected through in-depth interviews and field notes.

Results:

Thirteen nurses participated in individual interviews. Themes that emerged included awareness, motivation—empowering change, and barriers to evidence-based practice implementation (EBP). Several experienced nurses expressed the importance of EBP in practice but could not provide clear definitions of EBP. Personal and organizational barriers negatively influence EBP implementation in clinical practice. Nurses could be motivated to use EBP if it were translated in an easy way to understand.

Conclusion:

The information derived from this study can be used to design learning opportunities that prepare practicing nurses to appropriately appraise research and integrate evidence into practice.

J Contin Educ Nurs.
2018;49(7):299–306.
“I Am Surprised at the Change in Me”: What Is It Like for Nurses to Be in the Process of Completing a Baccalaureate Degree in Nursing?
Authors: Reese Cynthia E. , Ruppel Kelly J. , Matulis Brittany , Wendler M. Cecilia
Published: June 2018

Background:

The percentage of nurses with a baccalaureate degree in nursing (BSN) affects patient morbidity and mortality, so health care organizations are encouraging staff nurses to finish their BSN degree. However, there is little data related to what it is like for RNs to return to school.

Method:

In this qualitative, descriptive study, 16 RN-to-BSN students were interviewed using naturalistic inquiry processes to gain an understanding of what it is like for students in the midst of an RN-to-BSN program.

Results:

Students encountered financial and work–life barriers to seeking BSN completion yet found it to be worth the effort. Indeed, they are “surprised at the change in” themselves.

Conclusion:

Support that could benefit RN-to-BSN students is detailed, including from employers (e.g., flexible scheduling), faculty (e.g., rapid feedback and grading), and students themselves (e.g., understand personal time constraints). More research is needed to determine the priorities of support that facilitates RN-to-BSN students.

J Contin Educ Nurs.
2018;49(7):307–314.
Direct Visualization of Suspensory Fixation Deployment in Knee Ligament Reconstructions Without Fluoroscopic Imaging
Authors: Skelley Nathan W. , Stannard James T. , Laupattarakasem Pat
Published: June 2018

The authors describe a technique for visualizing the deployment of femoral suspensory fixation during ligament reconstructions that avoids the need for intraoperative fluoroscopic radiographs. Many surgeons currently use intraoperative fluoroscopic radiographs to confirm satisfactory deployment of the suspensory button on the femur; however, this technique involves prolonged surgical time, additional costs, and radiation exposure to the surgical team and patient. The authors' technique uses novel leg and camera positioning to allow for direct visualization of the button deployment. This technique can greatly improve operating room efficiency, save money, and decrease radiation exposure during surgery. [
Orthopedics
. 2018; 41(4):e587–e590.]
Hemiarthroplasty Is an Option for Patients Older Than 70 Years With Glenohumeral Osteoarthritis
Authors: Werthel Jean-David , Schoch Bradley , Adams Julie E. , Schleck Cathy , Cofield Robert , Steinmann Scott P.
Published: June 2018

Hemiarthroplasty (HA) of the shoulder has several potential advantages over total shoulder arthroplasty (TSA), particularly in the elderly population. This study reviewed long-term results of HA and TSA in patients older than 70 years with glenohumeral osteoarthritis. During a 30-year period, 403 shoulders had undergone HA (n=74) or TSA (n=329) for glenohumeral osteoarthritis. Outcome measures included pain, range of motion, and postoperative modified Neer ratings. All patients were included in the mortality and revision analyses. A total of 289 shoulders (44 HAs and 245 TSAs; mean patient age, 75 years) with a minimum of 5 years of follow-up or follow-up until revision were included. Both groups showed significant improvements in pain, abduction, and external rotation. No significant differences were detected between groups in postoperative pain, range of motion, or modified Neer ratings. Operative time was significantly lower in the HA group. There was no statistically significant difference detected in implant revision-free survival between TSA and HA (hazard ratio, 3.09) or in overall survival hazard ratio. At long-term follow-up, both HAs and TSAs provided good function in the elderly population. Patients who underwent TSA and patients who underwent HA had similar results, but the latter had a shorter operative time and lower revision rate. Hemiarthroplasty is a reasonable option for patients older than 70 years with end-stage glenohumeral osteoarthritis. [
Orthopedics
. 2018; 41(4):222–228.]
The Prolonged Analgesic Efficacy of an Ultrasound-Guided Single-Shot Adductor Canal Block in Patients Undergoing Total Knee Arthroplasty
Authors: Zhang Yanzi , Tan Zhen , Liao Ren , Zhou Zongke , Kang Pengde , Cheng Xu , Huang Kun , Yang Jing , Shen Bin , Pei Fuxing , Wang Xiao , Yang Jing
Published: June 2018

In this prospective, randomized, placebo-controlled study, the authors compared the analgesic efficacy of the single-shot adductor canal block (SS-ACB) vs the continuous adductor canal block (C-ACB) with intermittent boluses during the 72-hour postoperative period. Seventy-five patients randomly received the following: a single shot of 20 mL of 0.5% ropivacaine preoperatively followed by intermittent saline boluses at 12 hours and 24 hours postoperatively (SS-ACB group); 20 mL of 0.5% ropivacaine preoperatively and 12 hours and 24 hours postoperatively (C-ACB group); or saline preoperatively and postoperatively (control group). The primary outcome was visual analog scale pain scores with movement on postoperative day 1. The dynamic pain scores of the 2 ACB groups were equivalent and were lower than those of the control group on postoperative day 1. Compared with the control group, the 2 ACB groups were less likely to use opioids on the operative day and the first 2 postoperative days. The patients in the control group and the C-ACB group exhibited less quadriceps muscle strength than those in the SS-ACB group on postoperative day 1. The time required for an SS-ACB was markedly shorter than that required for an indwelling adductor canal catheter. Further, each adductor canal catheter cost $80. Patients who received a single block reported more satisfaction with their pain-relief treatment. Given the similar analgesic effect but better quadriceps muscle strength, easier execution, and higher patient satisfaction, the SS-ACB may be more suitable for total knee arthroplasty patients than the C-ACB. [
Orthopedics
. 2018; 41(5):e607–e614.]
La insostenibilidad de la Universidad pública neoliberal: hacia una etnografía de la precariedad en la Academia
Authors: Pérez Marta , Montoya Ainhoa
Published: June 2018

Partiendo de una preocupación por la Universidad, que cada vez más se sostiene sobre contratos precarios, apuntamos posibles aspectos a abordar en futuros análisis de la precariedad en la academia, especialmente de sus dimensiones más invisibles, aquellas que se concretan en prácticas neoliberales a las que nos adherimos en nuestro quehacer cotidiano y que (nos) vulnerabilizan a la par que convierten el trabajo en la academia en una labor individual y de competición. Al hacerlo, pretendemos encontrar otro imaginario de la labor académica, y de la Universidad, que recupere lo público como proyecto común a la vez que se interrogue sobre su naturaleza.
Tácticas del cuerpo: activismo y resistencia en la ciudad en crisis
Authors: Diz Carlos
Published: June 2018

El cuerpo es para el activismo contemporáneo el primer territorio de resistencia. Mediante una etnografía multisituada, desarrollada de 2008 a 2012 en España y otros países europeos, el análisis de sus usos políticos permitirá pasar de las «técnicas del cuerpo» (observadas por Mauss) a las tácticas del cuerpo. Además, en un contexto internacional de crisis política y socioeconómica, la ciudad se vuelve no solo el escenario de la acción, sino aquello que está en juego. El objetivo es comprender las resistencias del activismo con base en las interrelaciones del cuerpo y la ciudad, sabiendo que cuanto más se extiende esta última más importancia adquiere el primero. De la antiglobalización a movimientos recientes como el 15M, el cuerpo y la ciudad ganan un peso considerable.
La courte histoire du cimetière mérovingien de Banneville-la-Campagne (Calvados, France)
Authors: Hincker Vincent , Mayer Aurélie
Published: June 2018

En 2009, une fouille préventive menée préalablement à des travaux routiers a permis d’étudier dans son intégralité une petite nécropole mérovingienne installée en bordure immédiate d’une voie en usage depuis l’âge du bronze. Cette nécropole comprend environ 70 inhumations et a été utilisée tout au plus sur quatre générations. C’est au début du second quart du vie siècle que les premières sépultures sont implantées. Le noyau primitif comprend la tombe d’un porteur d’épée accompagnée des sépultures d’une jeune femme adulte et de trois fillettes dotées d’objets de parures. À la génération suivante, l’orientation des sépultures change, comme l’atteste la disposition des tombes d’un second couple comprenant un porteur d’épée et une femme plus richement dotée que les autres sépultures contemporaines. L’utilisation du cimetière se poursuit jusqu’à l’aube du viie siècle, alors que le chemin qui le longe continue à être emprunté bien au delà. Le mobilier déposé auprès des défunts illustre une volonté d’afficher une aisance sans cependant en avoir réellement les moyens.
Vieux-Conches (Eure), un site castral et son environnement (xie-xviiie siècle)
Authors: Debaene Tanguy
Published: June 2018

Un relevé topographique du site fossoyé de Vieux-Conches, mené dans le cadre d’un master et d’un projet collectif de recherche sur les fortifications de terre de Haute-Normandie, a mis en lumière la grande richesse du site. Les données de prospection ont conduit à élargir l’étude au paysage, au village, à l’église et à l’examen des activités artisanales et agricoles dont des témoignages subsistent sur le terrain. Le relevé topographique a mis en évidence une structuration autour de trois ensembles distincts : un pôle castral, un enclos paroissial et une zone de labours/culture. Il a été complété par des nettoyages de surfaces ciblés qui ont permis, entre autre, de dresser le plan de l’église Saint-Ouen. L’étude du site prouve sa longue occupation (xie-xviiie siècle) et amène à une relecture des sources historiques disponibles.
La part des femmes dans le développement d’une historiographie royale et d’une pensée politique léonaises aux XIIe et XIIIe siècles
Authors: Martin Georges
Published: June 2018

Cette étude se situe à la confluence d’une histoire politique de l’historiographie et d’une histoire sociale des femmes de pouvoir. Elle est portée par le souci de discerner l’importance et, au préalable, les lieux d’une intervention politique des femmes dans les royaumes hispaniques médiévaux. Pour l’espace et la période considérés – le royaume de León aux XIIe et XIIIe siècles –, l’entreprise n’a rien de facile et oblige à prendre en compte, au-delà de quelques données positives, des éléments indiciels permettant de formuler des hypothèses défendables. Dans le cadre de ce questionnement et de ces contraintes, on suivra, sous les formes fondamentales du patronage et de l’incitation, les traces d’une contribution féminine à l’émergence d’une grande historiographie royale et, conséquemment, à l’élaboration d’une pensée politique, puisque, au cours de cette période, celle-ci trouva dans l’histoire sa meilleure expression. Accessoirement, ces quelques réflexions pourront aussi être versées au dossier de l’histoire de l’infantat et du monastère-collégiale de Saint-Isidore de León.
Les fantômes sont des choses qui arrivent
Authors: Delaplace Grégory
Published: June 2018

Que se passe-t-il lorsque les morts apparaissent, lorsque les fantômes se manifestent ? Par-delà la diversité des contextes, des époques et des approches adoptées, il s’agit ici d’envisager les fantômes non seulement comme des choses auxquelles on croit (ou non), mais aussi et surtout comme des choses qui arrivent, comme des événements. Par les institutions qu’ils mettent en branle, les doutes qu’ils occasionnent ou les solutions auxquelles ils donnent lieu, ces événements activent les solidarités, ravivent les conflits et tracent le contour des collectifs ; en un mot, ils contraignent les vivants à recomposer leur monde. Documenter une apparition invite non seulement à se demander ce qui apparaît – à décrire la forme que peuvent prendre les fantômes à travers le monde – mais aussi ce que les apparitions font apparaître – ce qu’un fantôme rend visible lors de son surgissement.
Les voisins invisibles
Authors: Kwon Heonik
Published: June 2018

Les fantômes de la guerre abondent dans les villages vietnamiens d’aujourd’hui. Les longues guerres que le pays a connues de 1945 à 1975 ont pris une dimension internationale et, de la même façon, les ruines qu’elles ont laissées parmi les vivants ont elles-mêmes un caractère transnational. Cet article explore l’art de vivre, au Vietnam, avec des identités historiquement spectrales et néanmoins culturellement bien réelles.
Archéologie des machines occultes
Authors: BAUDOUIN Philippe
Published: June 2018

Dans cet article, l’auteur propose d’étudier l’usage que les communautés spirites et savantes firent, entre 1870 et 1910, des machines, dans les protocoles expérimentaux conçus pour communiquer avec les défunts. En s’appuyant sur les récits d’expériences rapportés par différentes figures et institutions majeures de cette période, il s’agit de montrer le rôle ambivalent de la machine dans les techniques de communication post-mortem mises en place par la doctrine spirite, puis d’analyser les enjeux épistémologiques des dispositifs mis en œuvre par les scientifiques pour contrôler les phénomènes produits par les médiums, dans le cadre d’expériences menées au sein des sociétés d’études psychiques.
Multi-Documents Summarization Based on TextRank and its Application in Online Argumentation Platform
Authors: Xiong Caiquan , Li Xuan , Li Yuan , Liu Gang
Published: June 2018

In an Online Argumentation Platform, a great deal of speech messages are produced. To find similar speech texts and extract their common summary is of great significance for improving the efficiency of argumentation and promoting consensus building. In this article, a method of speech text analysis is proposed. Firstly, a heuristic clustering algorithm is used to cluster the speech texts and obtain similar text sets. Then, an improved TextRank algorithm is used to extract a multi-document summary, and the results of the summary are fed back to experts (i.e. participants). The method of multi-document summarization is based on TextRank, which takes into account the position of sentences in paragraphs, the weight of the key sentence, and the length of the sentence. Finally, a prototype system is developed to verify the validity of the method using the four evaluation parameters of recall rate, accuracy rate, F-measure, and user feedback. The experimental results show that the method has a good performance in the system.
Predicting Shoppers' Continuous Buying Intention Using Mobile Apps
Authors: Prashar Sanjeev , Gupta Priyanka , Parsad Chandan , Vijay T. Sai
Published: June 2018

The rapid penetration of smartphones and consumers' increased usage/dependence on mobile applications (apps) has ushered favorable opportunities for retailers as well as shoppers. The traditional brick-and-mortar as well as online retailers must attract shoppers to use mobile shopping apps. For this, it is pertinent for retailers to predict users' continuous intention to buy through apps. To address this question, the present study has applied four prominent binary classifiers - logit regression, linear discriminant analysis, artificial neutral network and decision tree analysis to develop predictive models. Findings of the study shall help the marketers in accurately forecasting shoppers' buying behaviour. Various indices have been used to check the predictive accuracy of four techniques. The outcome of the study shows that the models developed using decision tree analysis and artificial neutral network provide better results in predicting consumers' continuous intention to buy through app. Based on the findings, the paper has also provided implications for the retailers.
Principal-Agent Analysis on How Legal Risks Affect Audit Fees and Quality
Authors: Giat Yahel
Published: June 2018

This article develops a principal-agent multi-period model that ties legal risks, auditing fees and internal accounting practices. The principal is the auditing firm and the agent is the client firm. The client firm can improve its credibility by improving its internal auditing practices, which results in lower audit fees to the auditor firm. It is found that in equilibrium, there is a credibility threshold level that firms should meet and which depends on the legal risks associated with accounting practices and audit errors. If, as result of strict legislation, a firm is below the threshold it will pay above optimal auditing fees. In this case, the firm should make a single, immediate improvement to reach the optimal level. Additionally, only firms whose credibility is close to the threshold are affected if government increases legal scrutiny. More credible firms are not adversely affected by the stricter legal climate.
EFEITO DO SISTEMA FINANCEIRO NA EVIDENCIAÇÃO SOCIOAMBIENTAL DE EMPRESAS EM PAÍSES EMERGENTES E DESENVOLVIDOS
Authors: Soares Rômulo Alves , Pinheiro Alan Bandeira , Abreu Mônica Cavalcanti Sá de , Marino Pedro De Barros Leal Pinheiro
Published: June 2018

O estudo avalia a influência do sistema financeiro da Austrália, do Brasil, do Canadá e da Índia sobre a extensão da divulgação de informações de responsabilidade social corporativa (RSC) de empresas de setores ambientalmente sensíveis. Para esse fim, foram selecionadas empresas dos setores de utilidade pública, materiais básicos e de operações de petróleo e gás, da Austrália, do Brasil, do Canadá e da Índia, presentes na lista da Forbes 2000 do ano de 2008. O período analisado compreendeu os anos de 2007 a 2014. A variável dependente de pesquisa é a extensão da divulgação de informações de RSC, divididas em três dimensões: ambiental, social e total. As variáveis independentes utilizadas relacionam-se com o sistema financeiro, além de variáveis de controle relativas às características das empresas (tamanho e adoção das diretrizes da GRI). Essas variáveis tiveram como fonte os bancos de dados do World Bank, do World Economic Forum, das bolsas de valores da Austrália, do Brasil, do Canadá e da Índia, além das informações existentes nos relatórios anuais e de sustentabilidade. A análise é feita por meio de estatísticas descritivas, ANOVA e regressão linear. Os resultados apontam que a extensão da divulgação de RSC se relaciona positivamente com as características do sistema financeiro. O trabalho conclui que os gestores devem dar atenção à influência das características das estruturas institucionais que moldam o Sistema Nacional de Negócios ao estabelecerem suas estratégias relacionadas à RSC.
Effect of Variation of Injection Moulding Parameters on Static and Dynamic Material Characteristics of Filled Polymer Materials
Authors: Contos Vaclav
Published: June 2018

A Continuum (filled polymer) is inhomogeneous and anisotropic. The Continuum is used in an injection moulding simulation at first (generally unnewton type of fluid). Then the continuum is solid (after cooling) and it is possible to carry out ordinary structural analysis with it both static and dynamic. The solid continuum has different mechanical properties for each of discrete element. The consequent values of mechanical characteristics (after simulation of load) will generally have different values when influence of injection moulding is taken into account for analyses.
Mixed Convection Heat Transfer around a Tandem Circular Cylinders in Incompressible Downward Flow
Authors: Laidoudi Houssem , Makinde Oluwole Daniel
Published: June 2018

In this paper, we numerically examine the mixed convective flow around a confined tandem heated circular cylinders embedded in a vertical channel in order to determine exactly the effects of opposing thermal buoyancy and distance between cylinders (S) on the behavior of fluid flow and heat transfer rate. The dimensionless governing equations involving momentum, continuity and energy are obtained and solved in a steady laminar flow regime for the conditions:Re= 5 to 40 andS= 0 to 5d, at fixed values of Prandtl numberPr= 1, Richardson numberRi= 1 and blockage ratioβ= 1/5. The fluid flow and temperature field are illustrated in terms of streamline and isotherm contours. The average Nusselt number is also computed to quantify the effect of fluid flow and heat transfer characteristics on amount of heat transfer rate.
Numerical Investigation of Power-Law Fluid Flows and Heat Transfer inside of Curved Duct under Aiding Thermal Buoyancy
Authors: Bouzit Fayçal , Laidoudi Houssem , Blissag Bilal , Bouzit Mohamed , Guenaim Abdellah
Published: June 2018

This paper deals with a numerical investigation in order to predict correctly the combined effects of aiding thermal buoyancy and rheological flow behavior of power-law fluids on downward flow and heat transfer rate inside of 180° curved duct. The governing equations involving the momentum, continuity and the energy are solved in two-dimensions using the package called ANSYS-CFX. The computational results are depicted and discussed for the range of conditions as:Re= 40 to 1000,Ri= 0 to-1 andn= 0.4 to 1.2 at fixed value of Prandt number ofPr= 1. To interpret the found results, the flow structure and temperature field are shown in form of streamlines and isotherm contours. The average Nusselt number of the inner and outer walls of curved channel is calculated to determine the role of Reynolds number, Richardson number and power-law index. It is found that increase in strength of aiding buoyancy creates a counter rotating region in angle of 90 degrees of the duct.
The Effect of Glutaraldehyde on Hydroxyapatite-Gelatin Composite with Addition of Alendronate for Bone Filler Application
Authors: Putra Alfian Pramudita , Rahmah Annisa Aulia , Fitriana Nia , Rohim Sayyidati Aristifanniy , Jannah Miftakhul , Hikmawati Dyah
Published: June 2018

Based on data from Indonesian Health Ministry in 2009, osteoporosis case reached 19,7 % of the populations in Indonesia, especially women in menopause period. The treatment was performed by consuming bisphosphonate drugs per oral which was not effective since the absorption intake of the drug was only less than 55% of the intake dosage. Because of that, the bone filler which also has a function as drug delivery system was developed. The hydroxyapatite-gelatin bone filler with the addition of alendronate was studied. To increase the characteristics of this bone filler, glutaraldehyde was introduced in the composite as a crosslinking agent. The concentration of 0.25%, 0.5%, and 0.75% were used. The bone filler was then characterized based on FTIR test, morphology test, compressive strength test, cytotoxicity test, and degradation test. The FTIR result showed that there was no significant difference between the sample with and without glutaraldehyde since the crosslinking bond of glutaraldehyde and gelatin was C=N bond which also presented in the gelatin. The morphology of the samples depicted a bigger pore size for higher glutaraldehyde concentration which also supported by lower compressive strength. All the samples were non-toxic based on the cytotoxicity test which had cell viability more than 100%. The degradation tests showed that with the presence of glutaraldehyde in the bone filler could maintain its form longer than the bone filler without glutaraldehyde. In conclusion, the presence of glutaraldehyde could increase the characteristics of the hydroxyapatite-gelatin composite with the addition of alendronate as a bone filler candidate for osteoporotic bone.
Numerical Evaluation of Biomechanical Stresses in Dental Bridges Supported by Dental Implants
Authors: Boukhlif Amel , Merdji Ali , Della Noureddine , Ould Chikh El Bahri , Mukdadi Osama , Hillstrom Rajshree
Published: June 2018

The number of supporting dental implants is an important criterion for the surgical outcome of dental bridge fixation, which has considerable impact on biomechanical load transfer characteristics. Excessive stress at the bone–implant interface by masticatory loading may result in implant failure. The aim of this study was to evaluate the impact of the number of implants supporting the dental bridge on stress in neighboring tissues around the implants. Results of the study will provide useful information on appropriate surgical techniques for dental bridge fixation. In this study, osseointegrated smooth cylindrical dental implants of same diameter and length were numerically analyzed, using three-dimensional bone–implant models. The effect of the number of supporting implants on biomechanical stability of dental bridge was examined, using two, three and four supporting implants. All materials were assumed to be linearly elastic and isotropic. Masticatory load was applied in coron-apical direction on the external part of dental bridge. Finite Element (FE) analyses were run to solve for von Mises stress. Maximum von Mises stresses were located in the cervical line of cortical bone around dental implants. Peak von Mises stress values decreased with an increase in the number of implants that support the dental bridge. Results of this study demonstrate the importance of using the correct number of supporting implants to for dental bridge fixation.
Bonding Calcium Chloride and Calcium Nitrate into Stable Hydration Portland Cement Products: Stability Conditions of Calcium Hydrochloraluminates and Calcium Hydronitroaluminates
Authors: Plugin Andrii A. , Runova Raisa F.
Published: June 2018

A thermodynamic analysis of the reactions of calcium chloride and calcium nitrate with tricalcium aluminate when used as a hardening accelerator for portland cement, as well as decomposition reactions of calcium hydrochloraluminate (CHChA) and calcium hydronitroalyuminate (CHNA) formed during the hardening was performed. The conditions of stable existence of CHChA and CHNA in the cement matrix were established.
A Review on Application of Novel Solid Nanostructures in Drug Delivery
Authors: Faraji Habibollah , Nedaeinia Reza , Nourmohammadi Esmaeil , Malaekeh-Nikouei Bizan , Sadeghnia Hamid Reza , Ziapour Seyyed Payman , Sarkarizi Hoda Khoshdel , Oskuee Reza Kazemi
Published: June 2018

Nanotechnology as a multidisciplinary and scientific innovation plays an important role in numerous biomedical applications, such as molecular imaging, biomarkers and biosensors and also drug delivery. A wide range of studies have been conducted on using of nanoparticles for early diagnosis and targeted drug therapy of various diseases. In fact, the small size, customized surface, upgraded solubility, or multi-functionality of nanoparticles enabled them to interact with complex cellular functions in new ways which opened many doors and created new biomedical applications. These studies demonstrated that nanotechnology vehicles can formulate biological products effectively, and this nano-formulated products with a potent ability against different diseases, were represented to have better biocompatibility, bioaccessibility and efficacy, under in vitro and in vivo conditions.
Formation of Single-Walled Carbon Nanotube Buckybooks, Graphene Nanosheets and Metal Decorated Graphene
Authors: Awasthi Seema , Awasthi Kalpana , Srivastava O.N.
Published: June 2018

The various carbon nanostructures e.g. single-walled carbon nanotubes (SWCNTs) web, graphene nanosheets and metal nanoparticle decorated graphene sheets have been synthesized in large quantity by electrical arc discharge method under an argon atmosphere. The as-synthesized nanostructures were characterized by different characterization techniques such as XRD, SEM, TEM, Energy dispersive X-ray spectroscopy, Raman and FTIR spectroscopy. The SWCNT webs of length ~6 cm abundantly containing aligned SWCNTs have diameter of about 1.8 nm and form buckybook like structure. Few layer graphene (FLG) sheets were prepared by electric arc discharge of high purity graphite electrodes in a varying argon gas atmosphere (250-500T). The largest areal extent of graphene (with lowest number of layer i.e. four) has been found at 350T argon pressure. A one step method is also reported for the decoration of these graphene nanosheets with iron and nickel nanoparticles through arc discharge method.
The Optical Properties of β-Cyclodextrin-Assisted Synthesize Worm-Like Ag2S by One Step Hydrothermal Method
Authors: Li Mao Hua , Li Xiao Fei , Ran Wen Sheng , Yang Bo
Published: June 2018

The worm-like morphology of silver sulfide (Ag2S) was successfully prepared via hydrothermal reaction at 150°C by using silver nitrate (AgNO3) and thioacetamide(CH3CSNH2) as both the sliver sources and sulfur sources, β-cyclodextrin as the template agent, and water as the solvent. The worm-like of Ag2S are characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), x-ray diffraction (XRD), x-ray photoelectronspectroscopy (XPS), energy dispersivex-ray (EDX), high-resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SEAD). Ultraviolet-visible spectra (UV-vis) and photoluminescencespectroscopy (PL) were used in an optical study of the products. The results showed that the existence of β-cyclodextrin is crucial to the formation of worm-like Ag2S, and the optoelectronics test results showed that the sample have a broad absorption in ultraviolet and visible light region.
Additive Manufacturing of Ti-6Al-4V with Added Boron: Microstructure and Hardness Modification
Authors: Jackson Ben , Torrens Rob , Bolzoni Leandro , Yang Fei , Fry Mike , Mukhtar Aamir
Published: June 2018

Titanium alloy composites with titanium boride (TiB) discontinuous reinforcement have shown improved performance in terms of strength, stiffness, and hardness. Producing this composite through selective laser melting (SLM) can combine the advantages of freeform design with the ability to produce TiB reinforcement in-situ. In this study, SLM was used to consolidate a pre-alloyed Ti-6Al-4V (Ti64) and amorphous boron (B) powder mixture with the intent of producing 1.5wt% TiB reinforcement in a Ti64 matrix. The processing parameters of laser power and scanning speed were investigated for their effect on the density, microstructures, and hardness of the composite material. The results showed that the boron and Ti64 composite could achieve a density greater than 99.4%. Furthermore, it was found that processing parameters changed the microstructural features of the material. The higher the energy density employed the more homogenous the distribution of boron modified material. Macro features were also observed with laser paths being clearly evident in the subsurface microstructure. Micro-hardness testing and density measurement also showed a corresponding increase with increasing energy density. Maximum hardness of 392.4HV was achieved in the composite compared to 354.2HV in SLM fabricated Ti64.
Optimizing HIP and Printing Parameters for EBM Ti-6Al-4V
Authors: Eklund Anders , Ahlfors Magnus , Bahbou Fouzi , Wedenstrand Jouni
Published: June 2018

An investigation of HIP parameters for EBM Ti-6Al-4V has been performed with the aim to maximize the strength of the HIPed material. A lower HIP temperature of 800 °C and a higher pressure of 200 MPa gives the highest strength and is also enough to eliminate all internal defects. By printing material with intentionally induced porosity combined with an optimized HIP cycle the highest strength can be obtained.
Titanium-Tantalum Alloy Powder Produced by the Plasma Rotating Electrode Process (PREP)
Authors: Yin Jin Gou , Chen Gang , Zhao Shao Yang , Tan Ping , Li Zheng Feng , Wang Jian , Tang Hui Ping
Published: June 2018

Microstructure of Ti-28Ta powders produced by plasma rotating electrode process (PREP) was investigated by using scanning electron microscopy (SEM), optical microscopy (OM), and transmission electronic microscopy (TEM). Phase constituent of the PREP Ti-28Ta powders was analyzed by X-ray diffraction (XRD). It was found that microstructure of the PREP Ti-28Ta powders was dependent on the powder particle sizes. Predominant martensitic α”, some metastable β and trace athermal ω phases were observed in the powders with the small diameter. While, phase constituent of the PREP Ti-28Ta powders with the large particle size was predominant metastable β, some martensitic α” and trace athermal ω. With the reduction of the powder particle size, the amount of martensitic α” increased and the metastable β decreased. The martensitic α” was formed preferentially on the metastable β grain boundaries of the PREP Ti-28Ta powders. The increase of α” phase and decrease of β with reduction of the powder particle size is attributed to the increase of the volume of the grain boundaries due to the grain refinement.
Joint Effect of Steel Addition and Press-and-Sinter on the Properties of Low-Cost PM Ti Alloys
Authors: Bolzoni Leandro , Ruiz-Navas Elisa Maria , Gordo Odériz Elena
Published: June 2018

Cheap alloying elements and creative processing techniques are a way forward to open up more industrial opportunities for Ti in sectors where it is not extensively applied yet, rather than in aerospace and biomedical applications. This study focuses on understanding the joint effect of using a commercial steel powder to add Fe to pure Ti and its processing by press-and-sinter on the behaviour of low-cost PM Ti alloys. It is found that the calibrated addition of steel permits to develop new low-cost Fe-bearing Ti alloys that can satisfactorily be produced using the blending elemental PM approach. Densification of the samples and homogenization of the chemical composition are enhanced by the high diffusivity of Fe. The low-cost α+β alloys reach comparable physical and mechanical properties to those of wrought-equivalent PM Ti alloys, such as Ti-6Al-4V, and are therefore promising candidates for load-bearing lightweight products.
A Simple and Economical Device to Process Ti Cylinders with Elongated Porosity by Freeze-Casting Techniques: Design and Manufacturing
Authors: Muñoz Paloma Trueba , Suárez Joaquín R. Bascón , Beltrán Ana M. , Rodriguez-Ortiz José Antonio , Hernández Yadir Torres , Palacio Juan José Pavón , Álvarez Esteban Alonso , Dunand David C.
Published: June 2018

Nowadays, the development of materials with gradient porosity is an important aim for many applications, especially in the field of bone tissue replacement. This research work shows the design and manufacture of a simple and economical device to process Ti cylinders with elongated and high interconnected porosity by freeze-casting techniques. The influence of the vessel material on the internal lamellar structure of the porous Ti samples is also studied. The device has been validated with: (i) a thermal gradient from-10 °C at the cold surface to 20 °C at the hot surface; and (ii) a cylindrical vessel with 12 mm diameter of alumina or Teflon. These working conditions have allowed maintaining the freezing conditions during the full process (alumina vessel: 30 minutes; Teflon vessel: 3 hours). After the solidification of the Ti aqueous suspension, the ice is sublimated (24 hours at-50 °C and 0.070 mbar). Then, the resulting powder is sintered (1150 °C for 5 h at high vacuum ~ 10-5 mbar), obtaining the porous Ti sample with the final structural strength. Finally, a detailed study of the most relevant porosity features is performed: porosity ratio and interconnectivity degree by Archimedes’ method, and size and shape of the pores by image analysis at three different zones along the longitudinal cross section. The results indicate the viability of the device to enhance the directional freezing and thus, the elongated porosity. Teflon vessel present the best results, with an average porosity ratio and porosity size of 39.5 % and 123.3 μm, respectively. This suggests an optimal biomechanical and bifunctional balance of this porous material.