bluuebunny/crossref_metadata_2025 huggingface dataset:
Combining Spitzer Parallax and Keck II Adaptive Optics Imaging to Measure the Mass of a Solar-like Star Orbited by a Cold Gaseous Planet Discovered by Microlensing
Authors: Beaulieu J.-P. , Batista V. , Bennett D. P. , Marquette J.-B. , Blackman J. W. , Cole A. A. , Coutures C. , Danielski C. , Prester D. Dominis , Donatowicz J. , Fukui A. , Koshimoto N. , Lončarić K. , Morales J. C. , Sumi T. , Suzuki D. , Henderson C. , Shvartzvald Y. , Beichman C.
Published: January 2018

To obtain accurate mass measurements for cold planets discovered by microlensing, it is usually necessary to combine light curve modeling with at least two lens mass–distance relations. The physical parameters of the planetary system OGLE-2014-BLG-0124L have been constrained thanks to accurate parallax effect between ground-based and simultaneous space-based Spitzer observations. Here, we resolved the source+lens star from sub-arcsecond blends in H-band using adaptive optics (AO) observations with NIRC2 mounted on Keck II telescope. We identify additional flux, coincident with the source to within 160 mas. We estimate the potential contributions to this blended light (chance-aligned star, additional companion to the lens or to the source) and find that 85% of the NIR flux is due to the lens star at H
L = 16.63 ± 0.06 and K
L = 16.44 ± 0.06. We combined the parallax constraint and the AO constraint to derive the physical parameters of the system. The lensing system is composed of a mid-late type G main sequence star of M
L = 0.9 ± 0.05 M
⊙ located at D
L = 3.5 ± 0.2 kpc in the Galactic disk. Taking the mass ratio and projected separation from the original study leads to a planet of M
p = 0.65 ± 0.044 M
Jupiter at 3.48 ± 0.22 au. Excellent parallax measurements from simultaneous ground-space observations have been obtained on the microlensing event OGLE-2014-BLG-0124, but it is only when they are combined with ∼30 minutes of Keck II AO observations that the physical parameters of the host star are well measured.
The HR 4796A Debris System: Discovery of Extensive Exo-ring Dust Material
Authors: Schneider Glenn , Debes John H. , Grady Carol A. , Gáspár Andras , Henning Thomas , Hines Dean C. , Kuchner Marc J. , Perrin Marshall , Wisniewski John P.
Published: January 2018

The optically and IR-bright and starlight-scattering HR 4796A ringlike debris disk is one of the most- (and best-) studied exoplanetary debris systems. The presence of a yet-undetected planet has been inferred (or suggested) from the narrow width and inner/outer truncation radii of its r = 1.″05 (77 au) debris ring. We present new, highly sensitive Hubble Space Telescope (HST) visible-light images of the HR 4796A circumstellar debris system and its environment over a very wide range of stellocentric angles from 0.″32 (23 au) to ≈15″ (1100 au). These very high-contrast images were obtained with the Space Telescope Imaging Spectrograph (STIS) using six-roll PSF template–subtracted coronagraphy suppressing the primary light of HR 4796A, with three image-plane occulters, and simultaneously subtracting the background light from its close angular proximity M2.5V companion. The resulting images unambiguously reveal the debris ring embedded within a much larger, morphologically complex, and biaxially asymmetric exo-ring scattering structure. These images at visible wavelengths are sensitive to and map the spatial distribution, brightness, and radial surface density of micron-size particles over 5 dex in surface brightness. These particles in the exo-ring environment may be unbound from the system and interacting with the local ISM. Herein, we present a new morphological and photometric view of the larger-than-prior-seen HR 4796A exoplanetary debris system with sensitivity to small particles at stellocentric distances an order of magnitude greater than has previously been observed.
Evidence of an Upper Bound on the Masses of Planets and Its Implications for Giant Planet Formation
Authors: Schlaufman Kevin C.
Published: January 2018

Celestial bodies with a mass of

have been found orbiting nearby stars. It is unknown whether these objects formed like gas-giant planets through core accretion or like stars through gravitational instability. I show that objects with

orbit metal-rich solar-type dwarf stars, a property associated with core accretion. Objects with

do not share this property. This transition is coincident with a minimum in the occurrence rate of such objects, suggesting that the maximum mass of a celestial body formed through core accretion like a planet is less than

. Consequently, objects with

orbiting solar-type dwarf stars likely formed through gravitational instability and should not be thought of as planets. Theoretical models of giant planet formation in scaled minimum-mass solar nebula Shakura–Sunyaev disks with standard parameters tuned to produce giant planets predict a maximum mass nearly an order of magnitude larger. To prevent newly formed giant planets from growing larger than

, protoplanetary disks must therefore be significantly less viscous or of lower mass than typically assumed during the runaway gas accretion stage of giant planet formation. Either effect would act to slow the Type I/II migration of planetary embryos/giant planets and promote their survival. These inferences are insensitive to the host star mass, planet formation location, or characteristic disk dissipation time.
Selective Disparity of Ordinary Chondritic Precursors in Micrometeorite Flux
Authors: Rudraswami N. G. , Fernandes D. , Naik A. K. , Shyam Prasad M. , Carrillo-Sánchez J. D. , Plane J. M. C. , Feng W. , Taylor S.
Published: January 2018

All known extraterrestrial dust (micrometeoroids) entering the Earth’s atmosphere is anticipated to have a significant contribution from ordinary chondritic precursors, as seen in meteorites, but this is an apparent contradiction that needs to be addressed. Ordinary chondrites represent a minor contribution to the overall meteor influx compared to carbonaceous chondrites, which are largely dominated by CI and/or CM chondrites. However, the near-Earth asteroid population presents a scenario with sufficient scope for generation of dust-sized debris from ordinary chondritic sources. The bulk chemical composition of 3255 micrometeorites (MMs) collected from Antarctica and deep-sea sediments has shown Mg/Si largely dominated by carbonaceous chondrites, and less than 10% having ordinary chondritic precursors. The chemical ablation model is combined with different initial chondritic compositions (CI, CV, L, LL, H), and the results clearly indicate that high-density (≥2.8 g cm−3) precursors, such as CV and ordinary chondrites in the size range 100–700 μm and zenith angle 0°–70°, ablate at much faster rates and lose their identity even before reaching the Earth’s surface and hence are under-represented in our collections. Moreover, their ability to survive as MMs remains grim for high-velocity micrometeoroids (>16 km s−1). The elemental ratio for CV and ordinary chondrites are also similar to each other irrespective of the difference in the initial chemical composition. In conclusion, MMs belonging to ordinary chondritic precursors’ concentrations may not be insignificant in thermosphere, as they are found on Earth’s surface.
Análise sensorial de iogurte elaborado com diferentes concentrações de extrato de café
Authors: Ribeiro João Felipe Alves , Bosi Mirela Guedes , Della Lucia Suzana Maria
Published: January 2018

O mercado consumidor tem aumentado seu interesse por alimentos benéficos à saúde. Um desses alimentos é o iogurte, que é muito apreciado por grande parte da população, por apresentar sabor suave e levemente ácido. Devido ao seu elevado consumo e importância econômica, o café é uma das bebidas mais importantes do Brasil. É apreciado em inúmeras variações em relação ao preparo da bebida, devido ao seu sabor e aroma característicos. O objetivo deste trabalho foi avaliar sensorialmente formulações desenvolvidas de iogurte sabor café. Foi realizado um teste de ordenação-preferência com quatro amostras de iogurte com diferentes concentrações de extrato de café (0,1; 0,3; 0,5 e 0,7 %), a fim de obter a formulação de iogurte preferida. Como as amostras testadas não diferiram significativamente em relação à preferência, a amostra selecionada para o teste de aceitação sensorial foi a que continha a menor concentração, 0,1 % de extrato de café, a fim de se minimizar o custo de produção. A formulação selecionada foi avaliada por meio do teste de aceitação em escala hedônica de nove pontos, obtendo uma boa aceitação entre os consumidores. Os resultados mostraram que o iogurte sabor café pode vir a atender a uma parcela do mercado, que busca por produtos diferenciados.
Técnicas e Materiais Empregados na Microencapsulação de Probióticos
Authors: Vaniski Rosane , Corti Daiane , Drunkler Deisy Alessandra
Published: January 2018

A microencapsulação é a tecnologia de envolver materiais sólidos, líquidos ou gasosos em pequenas cápsulas que liberam seu conteúdo sob condições controladas. Esta tecnologia tem sido utilizada para manter a estabilidade de probióticos durante o processamento e estocagem dos alimentos, além de aumentar a resistência no decorrer do trato digestório, possibilitando que estes cheguem ao intestino grosso com condições de sobrevivência e colonização. Durante o processo de microencapsulação, a escolha do material encapsulante é uma etapa de grande importância e deve se basear nas características do composto bioativo, da aplicação pretendida e do método de formação das partículas. Existem diversos técnicas que têm sido empregadas na elaboração de microcápsulas e a seleção do método mais adequado deve ser realizada com base nas propriedades físicas e químicas do material que será encapsulado e do agente encapsulante, analisando-se a finalidade de aplicação do ingrediente alimentício. O presente trabalho visa à revisão dos principais métodos e agentes encapsulantes utilizados na microencapsulação de microrganismos probióticos.
A dataset on the species composition of amphipods (Crustacea) in a Mexican marine national park: Alacranes Reef, Yucatan
Authors: Paz-Ríos Carlos , Simões Nuno , Pech Daniel
Published: January 2018

Alacranes Reef was declared as a National Marine Park in 1994. Since then, many efforts have been made to inventory its biodiversity. However, groups such as amphipods have been underestimated or not considered when benthic invertebrates were inventoried. Here we present a dataset that contributes to the knowledge of benthic amphipods (Crustacea, Peracarida) from the inner lagoon habitats from the Alacranes Reef National Park, the largest coral reef ecosystem in the Gulf of Mexico. The dataset contains information on records collected from 2009 to 2011. Data are available through Global Biodiversity Information Facility (GBIF).

A total of 110 amphipod species distributed in 93 nominal species and 17 generic species, belonging to 71 genera, 33 families and three suborders are presented here. This information represents the first online dataset of amphipods from the Alacranes Reef National Park. The biological material is currently deposited in the crustacean collection from the regional unit of the National Autonomous University of Mexico located at Sisal, Yucatan, Mexico (UAS-Sisal). The biological material includes 588 data records with a total abundance of 6,551 organisms. The species inventory represents, until now, the richest fauna of benthic amphipods registered from any discrete coral reef ecosystem in Mexico.
Influence of Teamwork on Health Care Workers' Perceptions About Care Delivery and Job Satisfaction
Authors: Dahlke Sherry , Stahlke Sarah , Coatsworth-Puspoky Robin
Published: January 2018

The aim of the current study was to examine the nature of teamwork in care facilities and its impact on the effectiveness of care delivery to older adults and job satisfaction among health care workers. A focused ethnography was conducted at two care facilities where older adults reside. Analysis of interviews with 22 participants revealed perceptions of teamwork and understandings about facilitators of and barriers to effective teamwork. Participants indicated that team relationships impacted care provided and job satisfaction. Participants also identified trust and reciprocity, communication, and sharing a common goal as critical factors in effective teamwork. In addition, participants identified the role of management as important in setting the tone for teamwork. Future research is needed to understand the complexity of supporting teamwork in residential settings given the challenges of culture, diversity, and individuals working multiple jobs. [
Journal of Gerontological Nursing, 44
(4), 37–44.]
Measurement of Nursing Home Culture Change: Systematic Review
Authors: Sturdevant Diana L. , Mueller Christine A. , Buckwalter Kathleen C.
Published: January 2018

Nursing home culture change (NHCC) aims to change the way care is provided in nursing homes. Valid and reliable measures are needed to evaluate the impact of NHCC on outcomes. The current systematic review provides an overview of instruments designed to measure NHCC and criteria for others to evaluate and choose instruments according to their own purpose. Ten instruments were identified that measure NHCC on an organizational level. Lack of development description hindered their assessment, and studies examining the relationship between NHCC and outcomes are rare. A common limitation of the instruments reviewed was the lack of psychometric testing; thus, their validity and reliability need further exploration.

[Res Gerontol Nurs. 2018; 11(2):103–112.]
El avance hacia la idiomatización del lenguaje pianístico a través de la edición de Clementi de las sonatas de D. Scarlatti (1791)
Authors: Cuervo Calvo Laura
Published: January 2018

Muzio Clementi es el editor de la primera publicación hasta ahora conocida para piano de las sonatas de Domenico Scarlatti: Scarlatti’s Chefs d’Oeuvre, for the Harpsichord or Piano forte [1791]. Esta obra contiene diez sonatas impresas del músico napolitano escogidas por Clementi de manuscritos del siglo XVIII a los que tuvo acceso. También contiene una sonata de Antonio Soler y otra sonata anónima.
La importancia de esta fuente radica en que posibilitó la difusión de una selección de sonatas de Scarlatti que antes solo eran accesibles a una minoría: Kk 378, 380, 490, 400, 475, 381, 206, 531, 462, 463; y además, que debido a numerosas revisiones editoriales específicas llevadas a cabo por Clementi para ser interpretadas al piano, presenta cambios significativos en el texto musical respecto a los manuscritos equivalentes.
A través del estudio de estas revisiones editoriales, se pretende aportar información sobre la práctica interpretativa de los instrumentos de tecla de finales del siglo XVIII, sobre las características de los pianos ingleses para los que Clementi realizó dicha revisión y sobre el avance del lenguaje idiomático específico del piano en esa época.
El teatro lírico como género difusor de las ideologías dominantes en torno a la Guerra de África (1859-1860)
Authors: García Torres Andrea
Published: January 2018

La mayor victoria propagandística e ideológica de la España isabelina fue la Guerra de África. La zarzuela juega aquí un papel importante para construir la imagen que se quiso dar entonces del país, y ello a pesar de que la mayoría de estas obras han tenido un éxito reducido. Aunque este trabajo no se plantea como un exhaustivo catálogo de obras, sí incorpora numerosos ejemplos en los que puede verse cómo los títulos de teatro lírico llevan implícito el mismo discurso oficial que difundía entonces el gobierno de O’Donnell. Contribuyen por ello en la construcción y difusión del imaginario colectivo que se implantó en España sobre los marroquíes y el avance colonial, e incluso del propio país dentro del contexto internacional. La supremacía moral, intelectual, religiosa y cultural de los españoles respecto a los musulmanes, junto al descrédito de éstos, articulan el discurso ideológico que se desprende también en este teatro.
Música y jardines en Granada. La impronta francesa de Debussy y Forestier en la creación artística española
Authors: Sanz García Laura
Published: January 2018

El objetivo de este artículo es ahondar en los aspectos que relacionan la creación de músicos y jardineros, españoles y franceses, en torno a la imagen de España, y la importancia del jardín en la inspiración visual de la música impresionista. Para ello se analizan los paralelismos temáticos y estilísticos existentes en la obra de dos artistas franceses, el músico Claude Debussy y el paisajista Jean-Claude Nicolas Forestier, en relación con el exotismo andalusí, y concretamente los jardines de Granada.
Al interés compartido por un imaginario que, para ambos creadores, representa la esencia de lo español, se une una misma intención renovadora y toda una serie de estilemas que traducen en términos artísticos su personal interpretación de Al-Andalus. Por otra parte, la influencia que tanto Debussy como Forestier ejercieron en los artistas españoles –como Falla y Javier de Winthysen–, conecta una vez más a Francia con el desarrollo de nuestras artes.
De este análisis interdisciplinar se deduce una sensibilidad común en el eje España-Francia y entre artes aparentemente tan alejadas como la música y la jardinería. Debussy y Forestier, así como sus “discípulos” españoles, pretenden combatir las imágenes románticas de España, utilizando el tópico hispanoárabe para renovar sus respectivos lenguajes, en la música y la arquitectura del paisaje, en la transición al siglo XX.
Algunos fragmentos de música española por la pianista Pilar Bayona. Análisis espectrográfico de su interpretación
Authors: Lorenzo Gracia Rubén
Published: January 2018

Pilar Bayona fue una figura relevante del piano en España durante el siglo XX que no ha sido estudiada hasta la fecha, desde el punto de vista técnico e interpretativo. Especialmente interesantes fueron sus interpretaciones de la música española.
En el presente trabajo realizo un análisis de algunos fragmentos que la pianista ha dejado grabados de este estilo. En mi análisis utilizo una metodología propia que permite realizar un diagnóstico objetivo de su interpretación mediante espectrogramas sonoros, imágenes y otras gráficas derivadas de ellos.
Organeros, músicos y empresarios: la familia De- Bernardi en Salamanca entre 1903 y 1932
Authors: Helvia García Martín Judith
Published: January 2018

A principios del siglo XX, Salamanca acogió a la que sería una de las familias cultural y musicalmente más activas de dicha ciudad durante las tres primeras décadas de la centuria: los De- Bernardi. Sus actividades como organeros, músicos, profesores y empresarios de la música, centradas en las figuras de Juan De- Bernardi y su hijo Luis, dejaron huella no solo en la ciudad mediante su participación en numerosos eventos culturales, sino también a través de la construcción y reparación de varios instrumentos en un área que abarca desde el norte de Portugal hasta el sur de Cáceres. Aquí reconstruimos, a través de la información contenida en fuentes hemerográficas locales, su trayectoria desde su llegada a Salamanca en 1903 hasta 1932.
Building Learning System for Content Knowledge and Social Knowledge
Authors: Syed Mustapha S.M.F.D
Published: January 2018

In the late 50’s or early 60’s, there were huge interests towards building learning systems for individual learning and they are called with various names such as Intelligent Tutoring System, Microworld, Computer Based Training, Computer Aided System, Intelligent Computer Aided Instruction and others. They are made to be different with regard to the technological approaches and the learning pedagogies, knowledge models and student models. Over the years, the interest of building learning systems has migrated from individual learning on content knowledge to community learning as the result of the recent Web 2.0 and Web 3.0 sociotechnological wave. The paper describes the work that was done to develop the learning system in both situations – content knowledge and social knowledge where the experiences mainly in capturing the knowledge and representing them are different
Enhanced Peer Assessment in MOOC Evaluation Through Assignment and Review Analysis
Authors: Alcarria Ramón , Bordel Borja , Martín de Andrés Diego , Robles Tomás
Published: January 2018

The rapid evolution of MOOCs in recent years has produced a change in the education of students and in the development of professional skills. There is an increasing pressure on universities to establish procedures for the recognition and certification of student participation in MOOCs. In order to guarantee that the evaluation procedures are in line with the quality of the procedures traditionally established in the university, a proposal for an enhanced peer assessment is required to allow a more precise review of the students' tasks and the assessments provided by his colleagues, considering procedures of verification of originality and a complete rubric for the peer review that takes into account reviewer’s history for a correct grade calibration. This paper describes the implementation of the evaluation tool, and an experimental validation that indicates that the majority of the students who have used the tool for the revision of assignments have generated grades closer to the revisions generated by the professors in the study.
Article retracted.
Authors: Editor Journal
Published: January 2018

This article has been retracted by the authors.
Role and Value of Learning Theories in the Area of Adaptive Educational Hypermedia Systems Incorporating Learning Styles
Authors: Tsortanidou Xanthippi , Karagiannidis Charalampos , Koumpis Adamantios
Published: January 2018

The purpose of this study was to investigate the pedagogical basis of Adaptive Educational Hypermedia Systems (AEHS) that incorporate Learning Styles concerning learning paradigms and learning theories through a meticulous review of the relevant published work. We investigated twenty (20) AEHS and analyze them comparatively to a variety of adaptivity determinants. Two are the pivotal points that are crucial in exploration of pedagogical approaches of these systems: the locus of control and the provided learning material. We conclude that these systems are based mostly on the learning paradigm of Cognitivism and Constructivism. In addition, we assume that the concept of learning theory is not such a narrow term, given that networked world imposes the concept of personal learning.
The Development of STEM Literacy Using the Learning Process of Scientific Imagineering through AR
Authors: Techakosit Somsak , Nilsook Prachyanun
Published: January 2018

The aim of this research was to 1) study the elements of STEM literacy for SIGAR and 2) study the development of STEM literacy by using SIGAR. The research methodology was divided into two phases: 1) reviewing literature on STEM literacy and studying each step of the SIGAR model. 2) Examining the suitability of the elements of STEM literacy and the development of STEM literacy by using SIGAR. The evaluation was undertaken by ten experts who hold doctoral degrees. The results showed that STEM literacy consisted of: 1) the ability to identify STEM problems, 2) the ability to seek new knowledge, 3) the application of the STEM concept, 4) the ability to solve problems using STEM, 5) the ability to communicate information relating to STEM, and 6) the ability to make decisions based on STEM. The experts also evaluated which step of SIGAR was most suitable for the development of the respective aspects of STEM literacy.
Designing and Evaluating the Use of Smartphones to Facilitate Online Testing in Second-Language Teacher Education (SLTE): An Auto-Ethnographic Study
Authors: Solihati Nani , Mulyono Herri
Published: January 2018

This paper reports on an auto-ethnographic study aiming to identify insights into the practice of using smartphone to facilitate online testing in context of second language teacher education (SLTE). In total of fifty-four pre-service teachers participated in the study. Two methods were employed to collect data, including observation and written-reflection. Additional data gathered from interview and students’ activity logs on the website were also used to triangulate the data collected through the initial methods. A thematic analysis were carried out to analyse the qualitative data. Findings of the study show that smartphone is viable as an electronic tool to facilitate online testing in SLTE context. More importantly, the use of Moodle as an online test platform fits both the teacher and the students’ needs on several aspects such as design, test structure, and online test activity. The study also highlights benefits and challenges of employing sequential and multiple attempt test modes and delayed feedback on online tests. Implications of the findings on the practice of online testing using smartphone in context of SLTE and further research in the field are also discussed.
Hoe hot is .brussels? Analyse van de introductie van de top level domeinnaam .brussels
Authors: Waty Margot , van Hooland Seth , Hengchen Simon , Coeckelbergs Mathias , De Wilde Max , Decroly Jean-Michel
Published: January 2018

De openstelling van de markt van de top level domeinnamen in 2012 bood nieuwe perspectieven voor bedrijven, overheden en privépersonen om een geografisch component op te nemen in de domeinnaam van hun website. Sindsdien werd er weinig tot geen onderzoek verricht om de introductie van de nieuwe top level domeinnamen (TLDN) te analyseren. Op basis van het specifieke geval van de TLDN .brussels, bespreekt dit artikel het empirisch onderzoek naar de mate waarin de openstelling van de markt van de top level domeinnamen de registratiepraktijken daadwerkelijk heeft beïnvloed. Door gebruik te maken van vrij beschikbare softwaretools, zoals OpenRefine en Natural Language Processing (NLP) methodes, werd het volledige corpus van de .brussels domeinnamen (6 300) vanuit kwantitatief oogpunt geanalyseerd. Op basis van een statistisch representatieve steekproef (592 domeinnamen), maakte een kwalitatieve interpretatie een verfijndere analyse mogelijk van de manier waarop de nieuwe TLDN in de praktijk wordt gebruikt. Op die manier geeft het artikel een gedetailleerd inzicht in de gevolgen van de recente wijzigingen van de regels inzake registratie van de domeinnamen. Dankzij deze analyse kunnen onderzoekers, beleidsmakers, investeerders en al wie om de identiteit van Brussel in de digitale wereld geeft, een beter inzicht krijgen van de stand van zaken van de .brussels TLDN.
The Variation of Plantar Temperature and Plantar Pressure during Shod Running with Socks or not
Authors: Wang Mei Zi , Song Yang , Fekete Gusztáv , Gu Yao Dong
Published: January 2018

Foot temperature can be affected by friction and contact pressure, in this study, we explored the specific changes of foot temperature under different friction conditions, running with socks versus no socks. The relationship between vertical loading force and foot temperature will also be investigated at the same time. Ten male recreational runners wore the same shoes and socks and were tested running 8km/h on a treadmill. The plantar temperature during running was recorded every 3 minutes for a total of 45 minutes. Post-run temperature change was recorded every 3 minutes for 12 minutes. The plantar pressure was recorded before running and at the first 15 minutes during running. The subjects with socks and no socks were tested on separate occasions. There were no significant differences found between the socks and no socks conditions. However, central metatarsal head, lateral metatarsal head, medial rearfoot and lateral rearfoot regions exist differences were reflected at the first 6minutes-12minutes of running. The foot temperature became more stable after 15minutes of running. Also, plantar pressure increased significantly in the hallux, other toes, first metatarsal head and central metatarsal regions. It also could conclude that lower initial temperature had a greater increase trend during the running start stage. When the ankle in plantarflexion stage, toe and forefoot regions showed a higher rise in temperature and also presented higher plantar pressure correspondingly.
Optimisation of a Reinforced Cement Spacer in Total Hip Arthroplasty
Authors: Salah Hichem , Bouziane Mohamed Mokhtar , Fekih S.M. , Bachir Bouiadjra Bel Abbès , Benbarek Smail
Published: January 2018

Infections total hip arthroplasty (THA) are common and can lead to serious complications for patients. Newly developed antibiotic spacers successfully eradicated infection in more than 90 percent of patients. However, the low mechanical strength of the orthopedic cement can be a serious handicap for the success of the surgical operation. The reinforcement of cement spacers with high strength materials can improve the efficiency of this type of surgery. In this study, the three-dimensional finite element method (FEM) is coupled with the experimental design method (EDM) to optimize the geometrical and mechanical properties of the reinforcement that can be applied to cements spacers. The obtained results show that the full stem reinforcement in bio-ceramic with a thickness of 8.2 mm can represent the optimal model to ensure good mechanical resistance of the cement spacer.
β-Dicalcium Silicate Cement Modified with β-Tricalcium Phosphate: In Vitro Bioactivity and Mechanical Strength
Authors: Bouregba Adil , Ez-Zaki Hassan , Sassi Omar , Diouri Adeljebbar
Published: January 2018

Calcium-silicate cement mainly based on dicalcium-silicate (C2S) was synthesized by the mean of solid state reaction. Beta-C3P was added to C2S to obtain C2S-C3P. Zinc oxide and bismuth oxide was incorporated to prepare radioc cement. In this work, the bioactivity and the mechanical strength of the synthesized cement were investigated. The in vitro test was carried out by immersion of cement pastilles in the artificial saliva in different periods from 4 hours to 30 days. Whereas the mechanical strength of some samples was operated at 28 and 72 days. The specimens are characterized by X-ray diffraction , Infrared spectroscopy and scanning electron microscopy. The finding results indicated that hydroxyapatite may appear after 24 hours of soaking; it was also shown that the presence of C3P with a small amount of the cement can enhance the bioactivity and develop more resistance strength of cement. Moreover, the addition of zinc oxide and bismuth oxide increase the radiopacity of the cement. However, the mechanical strength enhances with the incorporation of the zinc oxide while decrease with bismuth oxide. It was concluded then that there is possibility of combining addition of C3P (10%) and an agent radiopacifiers ZnO/Bi2O3 (15%) with small amounts on C2S to obtain a cement with excellent bioactivity, good mechanical strength and significante radiopacity that makes this material a great candidate as a biomaterial for biomedical use.
Wireless Heart Abnormality Monitoring Kit Based on Raspberry Pi
Authors: Alfarhan Khudhur A. , Mashor Mohd Yusoff , Mohd Saad Abdul Rahman , Omar Mohammad Iqbal
Published: January 2018

Heart monitoring kits are only available for bedridden patients and the traditional heart monitoring kits have many wires that are obstacle patients’ mobility. Most of the existing heart monitoring kits can not detect heart diseases. Thus, the current study proposed a wireless heart monitoring kit to monitor patients with a heart abnormality. The proposed kit can detect and classify four arrhythmia types as well as normal ECG with high accuracy. The design and development of the wireless heart abnormality monitoring kit (WHAMK) in this research were divided into three stages. These stages are the development of an arrhythmias detection and classification method using artificial intelligence approach, design and implementation of the kit hardware, and design and coding of the kit software. Arrhythmias classification approach is divided into four stages, namely obtaining the electrocardiograph (ECG) signals, preprocessing, features extraction and classification. The features extraction method are based on statistical features. The library support vector machine (LIBSVM) was used to classify the ECG signals. The hardware of the kit is divided into two parts, namely ECG body sensor (EBS), and processing and displaying unit (PDU). EBS working on acquiring the ECG signal from patient's body. PDU working on processing the collected ECG signal, plotting it and detecting the arrhythmias. Arrhythmias classification approach was developed by using statistical features and LIBSVM. They were implemented in the software of the kit to enable it to detect the arrhythmias in the real-time and fully automatically. The kit can detect and classify four arrhythmia types as well as normal sinus rhythm (NSR). These types of arrhythmia are premature atrial contraction (PAC), premature ventricles contraction (PVC), Bradycardia and Tachycardia. The proposed kit gave a good accuracy for detecting and classifying Arrhythmia with the overall accuracy of 96.2%.
An Empirical Inquiry into Maintenance Work of Auto-Mechanics and its Relative Bearing on Road Traffic Accidents - A Developing Country Case, Ghana
Authors: Agbo Aaron Agbenyegah , Li Wen Feng , Zheng Lan Bo , Atombo Charles
Published: January 2018

Road traffic accidents are challenges the world is battling in recent times. Majority of increasing road fatalities occurs in developing countries. This study seeks to address part of the issues leading to mechanical failures and road traffic accidents in the developing countries with Ghana as a case study. The study model was validated with the use of a sample collected from 880 mechanics from six regions. The mechanics completed questionnaire measures of perception on used parts, brand new parts, mechanical failure, road accidents and demographic variables. In addition, observation and survey method were also used to collect the data on work quality. The result shows that mechanical failure and road traffic accident correlated positively with used parts and negatively correlated with brand new parts. The study model explained R2 = 0.46 and 0.65 of the variance in mechanical failure and road traffic accident respectively. The independent predictors of mechanical failure were age, gender, experience, perception about used parts and work quality. The predictors of road traffic accident were experience, mechanical failure, perception about brand new parts and work quality. We conclude that the mechanical failure and road traffic accidents could be attributed to non-use of genuine parts, poor work quality standard and poor supervision during and after repairs. Remedial measures addressing these issues could reduce road traffic accident in Ghana.
Models for Solving Integrated Planning and Scheduling Problem: Computational Comparison
Authors: Hassani Zineb Ibn Majdoub , El Barkany Abdellah , Jabri Abdelouahhab , El Abbassi Ikram
Published: January 2018

This article concerns the integration of planning and scheduling production system. Planning and scheduling are usually treated separately because of their complexity. Scheduling largely depends on the production quantities computed at the production planning level. However, ignoring scheduling constraints in the tactical level leads to inconsistent decisions. So, it is important to integrate planning and scheduling to efficiently manage operations and to determine a realistic production plan for a given sequence of jobs on each machine. In this paper, we present some approaches proposed to solve the problem and we realize a comparison between the two most interesting ones, using the standard solver CPLEX.
Incidence of Calcic, Sulfates and Phosphates Salts on the Coagulation-Flocculation of Organic Compounds by Aluminium Sulfate
Authors: Hecini Linda , Achour Samia
Published: January 2018

The objective of this work is to evalute the coagulation-flocculation efficiency of the aluminum sulfate for the elimination of aromatic organic molecules (phenylalanine and catechol) in the presence of mineral salts of Ca2+ , SO42- and PO43-.Trials were conducted on the one hand on synthetic solutions of aromatic compounds in distilled water enriched by ions of calcium, sulphates and phosphate ions introduced in various forms (CaCl2 ; CaSO4 ; MgSO4 ; Na2SO4 ; NaH2PO4 ; KH2PO4), and on the other hand on Algerian drilling waters of different physicochemical characteristics. Results show that the addition of minerals salts seems to improve the yields of elimination of aromatic compounds tested and affects the optimal pH range of coagulation. The application of this process on mineralized waters (water drilling) leads to improve yields compared with those obtained in distilled water. It was also found that the process efficiency depends on the nature and the number of functional groups on the molecules and on their position relative to each other. The main mechanisms would be either a physical adsorption ,an exchange of ligand or a complexation on the floc surface of aluminum hydroxides.
Change of a Crack Propagation Rate in Fine-Grained Cement-Based Composites due to Partial Replacement of Aggregate by Ceramic Waste
Authors: Seitl Stanislav , Miarka Petr , Klusák Jan , Domski Jacek , Katzer Jacek , Šimonová Hana , Keršner Zbyněk
Published: January 2018

Concrete used in civil structures is usually made on cement-based matrix and natural aggregates (such as sand, gravel, crushed stone, etc.). Ceramic waste aggregate is considered as a perspective replacement of a part of natural aggregate in modern environmentally oriented building material. Concrete with natural aggregate partially replaced by ceramic waste aggregate usually show different mechanical characteristics than ordinary concrete. This paper introduces the pilot study of fatigue parameters of six concrete mixtures with various amount of ceramic waste. The experimentally obtain results are compared and discussed.
Input Value Correlation in Chloride Ion Ingress Modelling and Concrete Structures Reliability
Authors: Šomodíková Martina , Teplý Břetislav , Vořechovská Dita
Published: January 2018

The assessment of service life of a structure can be performed via mathematical modelling – either analytical or numerical and it can be viewed as a necessary pre-requisite for life-cycle engineering decisions. Many works concerning the modelling and testing of degradation effects for engineering systems are reported in the literature. The present paper discusses the degradation modelling of reinforced concrete structures and concentrates on the damage they sustain due to chloride ingress, namely a special aspect: the influence of statistical correlation among input variables on the reliability.
The Effect of Zinc on the Portland Cement Hydration
Authors: Šiler Pavel , Kolářová Iva , Másilko Jiří , Novotný Radoslav , Opravil Tomáš
Published: January 2018

Concrete is still the most commonly used building material. The main component of concrete is Portland cement. Due to increasing use of secondary products containing zinc, the amount of zinc in the clinker or in the secondary raw materials is increasing in recent years. Portland clinker can gain zinc from solid waste or tires which are widely used as a fuel for a burning in rotary kiln. In the case of secondary raw materials, zinc may be present in the primary material, where the manufacturing process leads to its removal and concentrating to "waste" which is used in the cement industry. The biggest problem with cement doped with zinc is the retardation of hydration and decreasing of mechanical properties. The main aim of this work is describing and evaluation of zinc effect on the course of Portland cement hydration.
Development of Sustainable Alternative Building Materials from Quarry Dust
Authors: Cohen Ehud , Bar Nes Gabriela , Peled Alva
Published: January 2018

The main goal of our work is to develop an alternative building material based on “zero waste” objective, thus creating commercially valuable products from materials that are otherwise high-volume waste products. Fine dolomitic quarry dust is a waste product manufactured in several millions of cubic tons each year in the mining industry of Israel. Our study examines a sustainable and useful solution to use this quarry dust (QD) as a part of fly ash based geopolymeric systems. Mechanical, thermal and chemical properties were examined and analyzed.
Design of Rapid Hardening Quaternary Zeolite-Containing Portland-Composite Cements
Authors: Sanytsky Myroslav , Kropyvnytska Tetiana , Kruts Taras , Horpynko Oleksander , Geviuk Iryna
Published: January 2018

The strength development of a quaternary Portland cement composite system containing blast-furnace slag, zeolitic tuff and limestone powder is presented. The composition and particle size distribution of the constituents are optimized by the incremental coefficient of the surface activity of the zeolite-containing Portland composite cements. Zeolitic tuff and limestone powder of high specific surface area lead to the increase of the surface activity of the entire system and a corresponding improvement in the performance of the cement.
Life Cycle Assessment of Natural Fibre Reinforced Cementitious Composites
Authors: Merta Ildikó , Mladenovič Ana , Turk Janez , Šajna Aljoša , Mauko Pranjić Alenka
Published: January 2018

Three cementitious composites containing different natural fibres (flax, hemp and sea-grass) were evaluated from an environmental perspective by means of Life Cycle Assessment (LCA) method applying the cradle-to-gate approach. The environmental impact of these composites was compared to that of cementitious composites reinforced with conventional synthetic polyacrilonitrile (PAN) fibres. The functional unit was the production of one cubic meter of cementitious composites ready-for-use. The results show that generally the environmental footprint of composite with synthetic fibres is bigger than the footprint of the composites with added natural fibres. Exceptions may only be the impacts on eutrophication and freshwater aquatic ecotoxicity, which are significantly affected by cultivation of crops. Flax and hemp cultivation is associated with emissions to soil and water. For this reason, the composite mixture with flax fibres has a significantly greater impact on eutrophication and freshwater aquatic ecotoxicity than the composite mixture with synthetic fibres. A cementitious composite mixture with sea-grass shows the lowest impacts in all impact categories. The entire life cycle of the studied composites was not included in this research since the life cycle of natural fibre composites is not straightforward and is highly dependent on the durability of the fibres within the matrix.
Inertization of Mine Tailing via Cold Consolidation in Geopolymer Matrix
Authors: Lancellotti Isabella , Kiventerä Jenni , Catauro Michelina , dal Poggetto Francesco , Illikainen Mirja
Published: January 2018

The consolidation via geopolymerisation is a room temperature alkaline chemical reaction of condensation between SiO2 and AlO2 monomers. Such a matrix can retain a large number of cations to compensate for the Al+3 in place of Si+4 in the tetrahedra. Arsenic-rich mine tailings from a gold mining site were activated with NaOH solution and commercial Na-Silicate (Na2O/SiO2 = 3) to produce a no-hazardous final material. Granulated blast furnace slag and metakaolin were used as co-binders to optimize the formulations. Leaching test was used to evaluate the inertization capability of the matrix after curing times of 7 and 28 days. The leaching results show that increasing curing time there is a significant decrease of As leaching due to the better consolidation of the material. Leaching of Cu, V, Ba and Zn significantly decrease, while Ni and Cr remain almost constant and Sb slightly increases.
Influence of Polymer Additives on Mechanical Fracture Properties and on Shrinkage of Alkali Activated Slag Mortars
Authors: Mikhailova Olesia , Šimonová Hana , Topolář Libor , Rovnaník Pavel
Published: January 2018

Alkali-activated slags represent an alternative to ordinary Portland cement due to reducing the environmental impact of the building industry. In spite of the numerous advantages of alkali activated slag mortars, alkali-activated aluminosilicates have big disadvantage – high value of shrinkage followed by formation of microcracks. This effect is caused by both autogenous and drying shrinkage and it finally results in volume contraction, microcracking and deterioration of the mechanical fracture properties. Therefore, using various types of polymer admixtures can overcome these problems. The aim of this paper is to present the effect of shrinkage-reducing admixture Peramin® SRA 40, polymer polyethylene glycol 1000 and polypropylene glycol on shrinkage and mechanical fracture characteristics of alkali-activated slag mortars. These admixtures were used in amount 0–2.0% weight of slag. The results showed that with increasing content of admixtures compressive and flexural strength decreased. Fracture tests with acoustic emission activity during this testing were carried out. Addition of 2% Peramin® SRA decreased shrinkage by 55%, but with 1% of Peramin® SRA the shrinkage was reduced only by 10%. Specimen with 1% of Peramin® is the most durable material, but more brittle compared to specimens with 1 and 2% of polypropylene glycol.
Shrinkage Behavior of Alkali-Activated Slag Cement Pastes
Authors: Omelchuk Vladyslav , Ye Guang , Runova Raisa F. , Rudenko Igor
Published: January 2018

Nowadays, alkali-activated cements (AACs) are the most promising alternatives to ordinary portland cement (OPC). Such cements characterized by better strength and corrosion resistance that determine improved durability of materials based on them. However, the shrinkage of AAC systems is noticeably higher compared with OPC. The purpose of this work was to study the shrinkage behavior of alkali-activated slag cement (AASC) pastes. To improve early age performance of AASCs – OPC and Ca(OH)2, as mineral additives, were added to the designed cement mixtures. The properties, like, flexural and compressive strength of cement mortars, chemical shrinkage, autogenous shrinkage and drying shrinkage of cement pastes were studied. The results showed that the chemical shrinkage, autogenous shrinkage and drying shrinkage at 28 days were between 0.064 – 0.074 ml/g, 4.5 – 7.9 mm/m and 3.3 – 4.9 mm/m, respectively. The relationship between the nature of alkaline components, the type of mineral additives and the shrinkage behavior of cements were discussed.
Pore Solution Composition and Solubility of Alkali-Activated Fly Ash
Authors: Zuo Yi Bing , Nedeljković Marija , Ye Guang
Published: January 2018

Pore solution of hardened alkali-activated fly ash paste was extracted by the steel-die method. The aqueous phase composition of pore solution was analyzed using ICP-OES analysis technique. The results show that the concentrations of Si, Al, Ca, K and OH- decrease with curing time regardless of the curing temperatures (40°C/60°C) and alkaline activators (sodium hydroxide with/without sodium silicate). On the contrary, the concentration of S increases with curing time. A higher temperature curing decreases the solubility of Si, Al, Ca and K in the alkali-activated fly ash, while it doesn’t show much influence on the solubility of S. The plot of the concentration of Al versus the concentration of Si displays a quasi-linear logarithmic relationship. This relationship implies congruent removal of Si and Al from the frameworks of fly ash.
Influence of Calcined Mine Tailings on the Properties of Alkali Activated Slag Mortars
Authors: Kotwica Łukasz , Chorembała Marcin , Kapeluszna Ewa , Stępień Piotr , Deja Jan , Illikainen Mirja , Gołek Łukasz
Published: January 2018

Influence of copper mine tailings on properties of soda activated ground granulated blast furnace slag mortars and pastes was investigated. Calcination of copper mine tailings was found to be a method of increasing their pozzolanic activity. Material calcined at 750°C possessed highest pozzolanic activity. So obtained material can be used as a partial substitution of ground granulated slag in soda activated blends. Introduction of calcined copper mine tailings decrease strength up to 28 days, but after 56 days strength results are similar or even higher comparing to control samples. Phase composition of hydrated material is not affected significantly by the presence of calcined copper mine tailings.