bluuebunny/crossref_metadata_2025 huggingface dataset:
Urban Science: Putting the “Smart” in Smart Cities
Authors: Shutters Shade T.
Published: September 2018

Increased use of sensors and social data collection methods have provided cites with unprecedented amounts of data. Yet, data alone is no guarantee that cities will make smarter decisions and many of what we call smart cities would be more accurately described as data-driven cities. Parallel advances in theory are needed to make sense of those novel data streams and computationally intensive decision support models are needed to guide decision makers through the avalanche of new data. Fortunately, extraordinary increases in computational ability and data availability in the last two decades have led to revolutionary advances in the simulation and modeling of complex systems. Techniques, such as agent-based modeling and systems dynamic modeling, have taken advantage of these advances to make major contributions to diverse disciplines such as personalized medicine, computational chemistry, social dynamics, or behavioral economics. Urban systems, with dynamic webs of interacting human, institutional, environmental, and physical systems, are particularly suited to the application of these advanced modeling and simulation techniques. Contributions to this special issue highlight the use of such techniques and are particularly timely as an emerging science of cities begins to crystallize.
Human Coronavirus Infections in Israel: Epidemiology, Clinical Symptoms and Summer Seasonality of HCoV-HKU1
Authors: Friedman Nehemya , Alter Hadar , Hindiyeh Musa , Mendelson Ella , Shemer Avni Yonat , Mandelboim Michal
Published: September 2018

Human coronaviruses (HCoVs) cause mild to severe respiratory diseases. Six types of HCoVs have been discovered, the most recent one termed the Middle East respiratory syndrome coronavirus (MERS-CoV). The aim of this study is to monitor the circulation of HCoV types in the population during 2015–2016 in Israel. HCoVs were detected by real-time PCR analysis in 1910 respiratory samples, collected from influenza-like illness (ILI) patients during the winter sentinel influenza survey across Israel. Moreover, 195 HCoV-positive samples from hospitalized patients were detected during one year at Soroka University Medical Center. While no MERS-CoV infections were detected, 10.36% of patients in the survey were infected with HCoV-OC43 (43.43%), HCoV-NL63 (44.95%), and HCoV-229E (11.62%) viruses. The HCoVs were shown to co-circulate with respiratory syncytial virus (RSV) and to appear prior to influenza virus infections. HCoV clinical symptoms were more severe than those of RSV infections but milder than influenza symptoms. Hospitalized patients had similar HCoV types percentages. However, while it was absent from the public winter survey, 22.6% of the patients were HCoV-HKU1 positives, mainly during the spring-summer period.
Rheology of Un-Sieved Concentrated Domestic Slurry: A Wide Gap Approach
Authors: Thota Radhakrishnan Adithya Krishnan , Van Lier Jules , Clemens Francois
Published: September 2018

Information on the rheology of domestic slurries is essential in designing pipeline transportation in novel sanitation systems. As concentrated slurries in their original collected state have wide particle size distribution, with particles up to 2 mm, a wide gap rheometer is used to acquire the rheograms. Rheograms obtained from a wide gap rheometer require a method to convert the rotational velocity to the shear rate, and this method must be robust to noisy data and yield stress in the slurry. For this purpose, a Tikhonov regularisation method is chosen as it suits the criteria the best. Using this, the rheograms are obtained for various total suspended solids (TSS) concentrations of slurries. A Herschel-Bulkley rheological model is used to represent the rheology of the slurries. The influence of the change in concentration of the slurries is represented through its influence on the Herschel-Bulkley parameters. The consistency index K exponentially increases with the concentration. The yield stress τ y , is 0 at low concentrations, and above 2.0% TSS (wt./wt.) exponentially increases with the concentration. The behaviour index n , is 1 at low concentrations, and above 2.6% TSS (wt./wt.) it decreases in an inverse power law with the concentration to reach a sort of plateau.
Identifying Surface Runoff Pathways for Cost-Effective Mitigation of Pollutant Inputs to Drinking Water Reservoir
Authors: Dąbrowska Jolanta , Dąbek Paweł B. , Lejcuś Iwona
Published: September 2018

Surface runoff (overland flow) is the main element of the water cycle and is also crucial in the delivery of phosphorus and nitrogen from catchments to water bodies. Watercourses and reservoirs in agricultural catchments are particularly vulnerable to the delivery of biogenic compounds via surface runoff. Forested riparian buffers are considered effective in reducing nutrients and sediment loads in runoff from agricultural areas. Regrettably, the concentration of surface runoff may significantly limit the buffering capacity of vegetation strips, as channelised overland flow tends to avoid buffers without making optimal use of their ability to retain nutrients and sediment. The aim of the undertaken research was to delineate surface runoff pathways from surrounding areas to a drinking water reservoir as well as to identify potential concentration spots of overland flow. The research was conducted for the Dobromierz drinking water reservoir (GPS N: 50°54′27″, E: 16°14′37″). The reservoir is situated in a submountain catchment, where rainfall is an important factor taking part in driving diffuse P and N loads from land to water. Presented GIS-based method using high resolution Digital Terrain Model obtained from Light Detection and Ranging (LiDAR) allowed to determine areas with a tendency for high accumulation (concentration) of overland flow in the direct catchment of the reservoir. As main surface runoff areas, three sites each exceeding 100 ha were designated. The analysis of spatial data also allowed to establish the risk of agricultural diffuse pollution transfer via channelised overland flow to the reservoir from individual accumulation areas. It was found that in the forested part of the catchment (serving as a riparian buffer) there is no visible tendency for concentration of surface runoff, but simultaneously the vegetation strip does not prevent the transfer of runoff waters from agricultural areas through the privileged pathways of concentrated flow.
Synergistic approach to polycycles through Suzuki–Miyaura cross coupling and metathesis as key steps
Authors: Kotha Sambasivarao , Meshram Milind , Chakkapalli Chandravathi
Published: September 2018

This account provides an overview of recent work, including our own contribution dealing with Suzuki–Miyaura cross coupling in combination with metathesis (or vice-versa). Several cyclophanes, polycycles, macrocycles, spirocycles, stilbenes, biaryls, and heterocycles have been synthesized by employing a combination of Suzuki cross-coupling and metathesis. Various popular reactions such as Diels–Alder reaction, Claisen rearrangement, cross-metathesis, and cross-enyne metathesis are used. The synergistic combination of these powerful reactions is found to be useful for the construction of complex targets and fulfill synthetic brevity.
Collaborative Efforts to Investigate Emissions From Residential and Municipal Trash Burning in India
Authors: Vreeland Heidi , Norris Christina , Shum Lauren , Pokuri Jaya , Shannon Emily , Raina Anmol , Tripathi Ayushman , Borse Dinesh , Patel Ankit , Dixit Pranjal , Bergin Michael H. , Stoner Brian R.
Published: September 2018

Emissions from trash burning represent an important component of regional air quality, especially in countries such as India where the practice of roadside, residential, and municipal trash burning is highly prevalent. However, research on trash emissions is limited due to difficulties associated with measuring a source that varies widely in composition and burning characteristics. To investigate trash burning in India, a collaborative program was formed among RTI, Duke University, and the India Institute of Technology (IIT) in Gandhinagar, involving both senior researchers and students. In addition to researching emission measurement techniques, this program aimed to foster international partnerships and provide students with a hands-on educational experience, culminating in a pilot study in India. Before traveling, students from Duke and IIT met virtually to design experiments. IIT students were able to visit proposed sites and offer specified knowledge on burning practices prior to the pilot study, allowing potential experiments to be iteratively improved. The results demonstrated a proof of concept of using a low-cost sensor attached to a commercial drone to measure emissions from a municipal dump site. In addition, for small-scale residential and roadside trash burning, a combustor was designed to burn trash in a consistent way. Results suggested that thermocouples and low-cost sensors may offer an affordable way for combustor designers to assess particulate emissions during prototype iterations. More experiences like this should be made available so that future research can benefit from the unique insights that come from having veteran researchers work with students and from forming international partnerships.
Reduction of Thermal Conductive Flux by Non-local Effects in the Presence of Turbulent Scattering
Authors: Emslie A. Gordon , Bian N. H.
Published: September 2018

The heat flux in a plasma is determined by the degree of anisotropy in the particle distribution function, which is in turn driven by gradients in the ambient density and temperature. When the mean free path at the thermal speed is substantially smaller than the scale length associated with the temperature variation, the heat flux simply depends on the local value of the temperature gradient. However, when the temperature scale length and mean free path are comparable, heat conduction becomes substantially non-local in character: the magnitude of the heat flux now depends on the overall temperature profile and is generally smaller than the locally determined value. In the presence of angular scattering associated with turbulence, the mean free path (and its velocity dependence) can be significantly smaller than its collisional value; this makes the expression for the heat flux more local in character, but also results in a heat flux that is lower than that obtained through a purely collisional analysis. Therefore, whether or not turbulence is present, the heat flux is generally smaller than the value obtained from a local collisional analysis. We here present an analytic expression for the conductive heat flux in terms of a convolution of the local heat flux with a non-local kernel function that incorporates both Coulomb collisions and turbulent scattering. We comment on the need to include both non-local and turbulent scattering effects in the modeling of quasi-static active region loops and in the conductive cooling of post-flare loops.
A Faraday Rotation Study of the Stellar Bubble and H ii Region Associated with the W4 Complex
Authors: Costa Allison H. , Spangler Steven R.
Published: September 2018

We utilized the Very Large Array to make multifrequency polarization measurements of 20 radio sources viewed through the IC 1805 H ii region and “Superbubble.” The measurements at frequencies between 4.33 and 7.76 GHz yield Faraday rotation measures (RMs) along 27 lines of sight to these sources. The RMs are used to probe the plasma structure of the IC 1805 H ii region and to test the degree to which the Galactic magnetic field is heavily modified (amplified) by the dynamics of the H ii region. We find that IC 1805 constitutes a “Faraday rotation anomaly,” or a region of increased RM relative to the general Galactic background value. The

due to the nebula is commonly 600–800 rad m−2. However, the observed RMs are not as large as predicted by simplified analytic models that include substantial amplification of the Galactic magnetic field within the shell. The magnitudes of the observed RMs are consistent with shells in which the Galactic field is unmodified, or increased by a modest factor, such as due to magnetic flux conservation. We also find that with one exception, the sign of the RM is that expected for the polarity of the Galactic field in this direction. Finally, our results show intriguing indications that some of the largest values of

occur for lines of sight that pass outside the fully ionized shell of the IC 1805 H ii region but pass through the Photodissociation Region associated with IC 1805.
Magnetic Fields in the Galactic Halo Restrict Fountain-driven Recycling and Accretion
Authors: Grønnow Asger , Tepper-García Thor , Bland-Hawthorn Joss
Published: September 2018

The Galactic halo contains a complex ecosystem of multiphase intermediate-velocity and high-velocity gas clouds whose origin has defied clear explanation. They are generally believed to be involved in a Galaxy-wide recycling process, either through an accretion flow or a large-scale fountain flow, or both. We examine the evolution of these clouds in light of recent claims that they may trigger condensation of gas from the Galactic corona as they move through it. We measure condensation along a cloud’s wake, with and without the presence of an ambient magnetic field, using two- (2D) and three-dimensional (3D), high-resolution simulations. We find that 3D simulations are essential to correctly capture the condensation in all cases. Magnetic fields significantly inhibit condensation in the wake of clouds at t ≳ 25 Myr, preventing the sharp upturn in cold gas mass seen in previous non-magnetic studies. The magnetic field suppresses the Kelvin–Helmholtz instability responsible for the ablation and consequent mixing of a cloud with halo gas which drives the condensation. This effect is universal across different cloud properties (density, metallicity, velocity) and magnetic field properties (strength and orientation). Simple convergence tests demonstrate that resolving the gas on progressively smaller scales leads to even less condensation. While condensation still occurs in all cases, our results show that an ambient magnetic field drastically lowers the efficiency of fountain-driven accretion and likely also accretion from condensation around high-velocity clouds. These lower specific accretion rates are in better agreement with observational constraints compared to 3D, non-magnetic simulations.
The Relationship Between Lifestyle, Health Promotion Lifestyle Profile II And High Blood Pressure In University Students
Authors: Aynaci Gülden , Akdemir Ozlem
Published: September 2018

BACKGROUND: Identifying and controlling systemic arterial blood pressure is important in young people, and it is possible to reduce the frequency of systemic arterial hypertension by improving the lifestyle.
AIM: The aim of the study is to assess the relationship between healthy lifestyle behaviors and systemic blood pressure in university students.
MATERIALS: The study sample consisted of 200 university students from a state university in Edirne. Lifestyles and habits were evaluated with Health Promotion Lifestyle Profile II. Students’ blood pressure was measured from both arms twice.
RESULTS: The mean HPLP-II score of those who frequently feel good was significantly higher than those who rarely feel good. The mean score of those who frequently wake up between 06:00-09:00 in the morning was statistically significantly higher than those who wake up outside these hours. Those who perform social or artistic activities during their leisure times had a mean scale score higher than those who don’t perform. Although there wasn’t a statistically significant difference according to smoking status, the mean score of non-smokers was higher than smokers. The mean scale scores were higher in frequent salt users than non-frequent users; participants with low saturated fatty acid intake had higher scores than those with high intake, and rare fast food consumers had higher scores than frequent consumers. The statistically significant difference between blood pressure values of females and males was due to higher blood pressure in male students. Those working in a part-time job had higher blood pressure values than those who weren’t working. Among the students whose body mass indexes could be evaluated, there were differences in blood pressure values.
CONCLUSION: It has been observed in our study that health-related responsibilities and lifestyle behaviours increase with better leisure time activities, improved eating habits and a positive outlook on life. Turning youngs’ tendencies towards healthy lifestyle behaviours to habits can make them healthier, more collective and more productive regarding physical, social and psychological well-being.
Au creux de l’intime. Familles et sociabilités de l’entre-deux à Madagascar pendant la période coloniale (1896-1960)
Authors: Tisseau Violaine
Published: September 2018

Les unions entre Malgaches et étrangers ont joué jusqu’à la fin du xix e siècle un rôle important à la fois dans les processus d’intégration de ces derniers à Madagascar et dans le fonctionnement de réseaux commerciaux de longue distance. L’annexion de l’île modifie la place de ces alliances et des personnes qui en sont nées, les plaçant sous le regard souvent suspicieux des colonisateurs comme des colonisés. Pourtant, le métissage reste un moyen de mise en relation de différents types de réseaux. Je m’intéresserai aux unions entre Européens et Malgaches et à leurs descendants, en Imerina, pendant la période coloniale (1896-1960), qu’il s’agisse de concubinage ou de mariages régularisés. À travers l’analyse des registres d’état civil européens et surtout de récits de vie, je propose de montrer comment, au creux de l’intime, des réseaux européens et malgaches s’articulent, permettant la mobilité et l’ancrage territorial des individus. Pour cela, je mettrai en lumière la manière dont les migrants européens se constituent des réseaux familiaux et de sociabilités : par leur union avec des femmes malgaches, des Européens s’insèrent dans des réseaux locaux et, d’une génération à l’autre, leurs familles s’enracinent dans le territoire malgache. En parallèle, une fois installés, certains d’entre eux maintiennent des liens avec la métropole en faisant venir des membres de leur famille d’origine et en envoyant leurs enfants métis y poursuivre des études. Au fil du temps, des réseaux entre familles métisses se constituent, favorisés par la fréquentation d’établissements scolaires communs, le passage par des institutions recueillant des métis et l’exercice de professions similaires. Les familles métisses incarnent ainsi la connexion entre des sociabilités européennes et malgaches et dessinent une sociabilité de l’entre-deux, entre colonisateurs et colonisés.
Die Dreigroschenoper « Off-Broadway » (1954-1961). Marc Blitzsteins Bühnenfassung für das New Yorker Theater de Lys
Authors: Roger Christine
Published: September 2018

« J’aurais aimé écrire L’Opéra de quat’sous , mais comme je ne suis que son traducteur et adaptateur pour le public américain, je peux dire en toute franchise que cette œuvre tient du miracle », déclare le compositeur américain Marc Blitzstein à propos de la pièce de Kurt Weill et de Bertolt Brecht dans un essai publié dans la revue Musical Show en octobre 1962. Dix mois auparavant, le Theater de Lys (l’actuel Lucille Lortel Theater), un théâtre off-Broadway situé dans le quartier de Greenwich Village, avait déprogrammé son plus grand succès théâtral, après 2 707 représentations données devant 750 000 spectateurs durant sept ans. En 1954, le public new yorkais avait pris en passion L’Opéra de quat’sous , un engouement qui n’était pas sans rappeler la véritable « fièvre » déclenchée à Berlin et à travers toute l’Europe continentale à la fin des années 1920 par les mises en scène de cette « pièce avec musique ». Sept ans plus tard, la reprise américaine à petit budget, présentée en dehors du circuit traditionnel de diffusion des spectacles à New York, avait fini par éclipser Oklahoma ! , le grand événement théâtral de Broadway. Entre-temps, The Threepenny Opera était devenue l’une des productions à l’origine du développement des scènes off-Broadway comme nouveaux lieux alternatifs d’expérimentation théâtrale. À la fois projet artistique pointu et succès commercial tant inattendu qu’habilement exploité, l’adaptation de Die Dreigroschenoper est un jalon dans l’histoire théâtrale américaine du xx e siècle. Grâce au célèbre Mack the Knife , elle a récemment fait son entrée dans le Registre du patrimoine culturel américain.
« Faut-il que nous soyons gouvernés par un roi ? » La fable des arbres (Jg 9,8-15) entre la satire et l’apologie
Authors: Martins Francisco
Published: September 2018

Cet article reprend la question de la signification et de la fonction sociale de ladite fable des arbres (Jg 9,8-15). Ce texte demeure une véritable crux interpretum , comme le montre la brève description du status quaestionis . Analysant de manière systématique chacun des éléments de ce court récit, Francisco Martins concentre son étude sur les possibles implications de l’identification du avec un arbre du genre Zizyphus. Selon cette lecture, la satire du régime monarchique n’est pas le seul objectif de la fable : le « roi-ʾāṭād » est une figure de la mission qu’un tel régime peut assumer dans les espaces et les occasions de détresse.
OIT, justice sociale et mondes communistes. Concurrences, émulations, convergences
Authors: Kott Sandrine
Published: September 2018

Cette contribution vise à réinterroger les valeurs et choix fondamentaux de l’Organisation internationale du travail (OIT), à l’aune de sa relation d’opposition/complémentarité avec les mondes communistes. Le pluriel se justifie ici parce que, contrairement à l’image qui en a été construite et diffusée à des fins de propagande durant la guerre froide, le communisme est loin d’être un « monolithe ». Trois groupes occupent des positions différentes et font entendre une parole différenciée au sein de l’OIT ; ils dévoilent trois modalités de la relation entre l’Organisation et les mondes communistes qui permettent, en retour, de mettre en évidence trois caractéristiques de son action. Le mouvement communiste international témoigne d’abord d’une hostilité forte à l’égard d’une organisation dont il condamne la conception libérale de la justice sociale. Ensuite, à partir de 1934, mais surtout après la Seconde Guerre mondiale, les représentants des États socialistes militent pour des droits sociaux extensifs et favorisent ainsi la formulation d’un projet social réformateur. Enfin, à partir des années 1960, les cadres des régimes communistes utilisent l’expertise fournie et encouragée par l’OIT afin d’accroître la productivité du travail. Cette convergence productiviste interroge, in fine , l’idée même de justice sociale.
Utilisation of house fly maggots (Musca domestica) as replacement for fish meal in the diets ofClarias gariepinus juveniles
Authors: Ipinmoroti M.O. , Akanmu O.A. , Iyiola A.O.
Published: September 2018

Fish meal is widely used in commercial feed production because of its amino acids profile, and high protein content, however, its usage constitutes a major cost in fish feed production. It is therefore essential to source for a highly nutritious, cheap and readily available substitute which can supply the farmed fish with necessary dietary requirements for proper growth and development. The study utilised house fly maggots (Musca domestica) cultured from poultry waste at varying inclusion levels of 0 (no inclusion), 25, 50, 75 and 100% (maggot inclusions) to replace fish meal in the diets and replicated thrice. A total of 180Clarias gariepinus juveniles catfish with initial average weight of 10.11±0.12 g were stocked at 12 fish per tank, acclimatised for 2 weeks and fed twice daily at 3% body weight for a period of 12 weeks. The proximate composition of wet maggots showed the presence of favourable amino acids similar to fish meal but had lower crude protein content (47.45%) with high ether extract (22.23%) and moisture content (83.52%). The water quality parameters such as ammonia, temperature and dissolved oxygen were monitored daily and showed no significant difference (P<0.05) among the treatments and were tolerable for fish culture. Sampling of fish was done weekly, the growth and nutrient utilisation, economic indices and haematological studies were done and analysis of variance was used for the statistical analysis. It was observed that 75% inclusion of wet maggot gave better results and rapid utilisation and conversion of feed to flesh and was evident in the weight gain (50.71 g), lowest feed conversion ratio (1.04±0.04), highest specific growth rate (1.99±0.00 g/day) and cheap in terms of cost of production (₦ 172.12). This shows that 75% of wet maggots can be recommended as an inclusion level in commercial fish feed for adequate utilisation byC. gariepinus juveniles.
Apertura comercial y distribución de la renta en países en desarrollo: un análisis de la experiencia de Irlanda
Authors: Morillas Martínez Juan Rafael
Published: September 2018

En este trabajo se analizan los efectos distributivos de las estrategias de desarrollo basadas en la promoción de las exportaciones y la atracción de inversiones extranjeras. En concreto, se analizan las consecuencias de la estrategia de desarrollo seguida en Irlanda. Una larga tradición en economía y sociología del desarrollo ha mantenido que la apertura comercial tiene consecuencias igualitarias sobre la distribución de la renta en los países en vías de desarrollo. En este trabajo presento los fundamentos teóricos de esta afirmación y los discuto a la luz de las críticas realizadas por nuevas teorías del desarrollo. El análisis de la experíencia de Irlanda constituye un caso especialmente adecuado para probar empíricamente las proposiciones derivadas de ambas teorías.
Mercados de trabajo en la ciencia: balance de la investigación y propuesta de marco analítico
Authors: Fernandez Esquinas Manuel
Published: September 2018

El mercado de trabajo en las instituciones científicas, además de ser un proceso de compra-venta de fuerza de trabajo, es el ámbito en el que se produce la intersección entre los principios de funcionamiento de la ciencia contemporánea y los procedimientos de trabajo de los grupos y las organizaciones científicas, entre las capacidades y actitudes de los trabajadores y los criterios empleados para adaptarlos a los procesos del trabajo de investigación. Por ello, el mercado de trabajo constituye un elemento privilegiado para observar el fimcionamiento de la investigación científica en sus diversos marcos organizativos y es un factor clave en el desarrollo de cualquier sistema de I+D. En este trabajo se realiza una revisión de las principales aportaciones que han tratado el proceso de incorporación y movilidad de trabajadores científicos y la estructuración del sistema de ocupaciones en la ciencia, se expone un marco analítico que utiliza los conocimientos acumulados en este área de problemas y se desarrolla un esquema operativo para la investigación empírica de los diversos mercados de trabajo tanto en la ciencia académica como en la industrial.
Las consecuencias electorales de la movilización territorial: las estrategias del partido popular en la campaña de 1996
Authors: Criado Olmos Henar
Published: September 2018

En este artículo se analiza el impacto de las estrategias de movilización territorial en el voto de los electores. En concreto, se estudian los efectos de las visitas del candidato del partido, el gasto descentralizado y la inclusión de figuras conocidas en las listas provinciales, en el voto de los electores que residen en estas circunscripciones. Frente a los trabajos que analizan el impacto de las características individuales de los electores, se ha estimado un modelo multinivel que permite comprobar el efecto de las variables de movilización de los partidos en las circunscripciones.
Cambios en las pautas de fecundidad de la comunidad de Madrid. Los procesos de inmigración como factor explicativo
Authors: Cebrian Inmaculada , Iglesias Carlos , Moreno Gloria , Llorente Raquel
Published: September 2018

El artículo analiza los cambios observados en el índice de fecundidad de la Comunidad de Madrid (CM) que, tras años de constante reducción, comienza a crecer ligeramente a partir de 1995. Para ello, después de analizar el patrón de comportamiento de los nacimientos en la CM, considera dos factores explicativos altemativos: los cambios en la composición por edades de las mujeres madrileñas fértiles, y sus diferencias en términos de fecundidad, y el tamaño de la población inmigrante y su comportamiento reproductivo. Las conclusiones señalan que, a pesar de que la población inmigrante está desempeñando un papel de cierta importancia en la recuperación de la natalidad en la CM, no es el único factor que debe tenerse en cuenta. Las mujeres madrileñas entre 30 y 39 años, tras haber renunciado a la maternidad en edades más jóvenes, se plantean actualmente tener hijos, de forma que se observa un claro incremento de la tasa específica de fecundidad de este colectivo.
The Fabrication of Graphene-Reinforced Aluminum Composites by Powder Metallurgy and Uniaxial Pressing
Authors: Buasri Achanai , Prasanwon Chudeth , Boonsong Bhornwalan , Kohprasert Pantira , Loryuenyong Vorrada
Published: September 2018

This research studied the fabrication of graphene-reinforced aluminum composite via powder metallurgy and uniaxial pressing. The process started from mixing graphene with aluminum powder with various content of graphene (0.5, 1, 1.5, 2 and 4 wt.%) in acetone medium, followed by dispersion process at high frequency using an ultrasonic bath. The mixed composite powders were then formed into pellet and sintered at 600°C. The results showed that when graphene content in graphene reinforced aluminum composite is low (0.5wt.%, 1wt.% and 1.5wt.%), the hardness was enhanced. It was suspected that graphene could get into aluminum matrix and impede the grain growth of aluminum and dislocation movement. However, when excessive graphene content was added, graphene nanoplatelets tended to agglomerate, decreasing the hardness of composite. Similarly, the improvement of electrical and thermal conductivities was achieved with a low content of graphene. The well dispersion of graphene in aluminum matrix could facilitate the electron transport and to induce the pore reduction throughout the matrix.
Evaluation of Face Milling Operation Parameters on Surface Roughness of Crankcase Housing by Two Level Factorial Design with Center Points
Authors: Thanasuptawee Ukrit , Thakhamwang Chamrat , Siwadamrongpong Somsak
Published: September 2018

In this study, there are three machining parameters consist of spindle speed, feed rate and depth of cut which were conducted through full factorial with four center points to determine the effect of machining parameters on the surface roughness and verify whether there is curvature in the model for CNC face milling process in an automotive components manufacturer in Thailand. The workpieces used semi-solid die casted ADC12 aluminum alloy crankcase housing which they were performed by the ARES SEIKI model R5630 3-axis CNC vertical machining center and face milling cutter with diameter of 63 millimeters. The surface roughness of face-milled was measured by the surface roughness tester. It was found that the greatest main effect influence to surface roughness was spindle speed, followed by feed rate and depth of cut at significance level of 0.05.
Manufacturing Technology of α-Fe Bonded Grinding Wheel Free Abrasive
Authors: Kuai Ji Cai , Ardashev Dmitry V. , Zhang Jia Qi , Zhang Hua Li
Published: September 2018

ELID ultra-precision grinding mirror surface can achieve nanometer precision. However, after the grinding wheel passivates the abrasive particles in electrolysis, it is easy to scratch the ultra-precision ELID grinding surface into the grinding process. In order to solve this problem, a non-abrasive grain α-Fe bonded grinding wheel is propose, which contains no abrasive particles. After electrolysis, oxide film is formed on the surface of the wheel. In ultra-precision ELID grinding, there is no abrasive particles involved, only the polishing effect of oxide film. There is no need to worry about the scratching of exfoliated abrasive particles that have been machined on ultra-precision ELID surfaces. Thus achieving extremely high surface accuracy.
Response of Osteoporotic Bone to the Implantation of Biphasic Calcium Phosphate (BCP) Bioceramics
Authors: Grisulonoks Aleksandrs , Salma Ilze , Salms Girts , Neimane Laura , Skagers Andrejs , Locs Janis
Published: September 2018

Osteoporosis is a chronic, metabolic and systemic skeletal disease characterized by low bone mineral density (BMD) and micro-architectural deterioration, resulting in increased bone fragility and fracture risk. Changes in the mineral structure occur due to aging or because of progressive pathologic processes such as osteoporosis, as well as in both aging and effects of bone diseases.
Modeling of Phases Adhesion in Composite Materials Based on Spring Finite Element with Zero Length
Authors: Sokolov Alexander Pavlovich , Schetinin Vitaliy Nikolaevich
Published: September 2018

A new numerical method for homogenization of elastic properties of dispersedly-reinforced composites was presented. The method takes into account special model of adhesive contact. Homogenization of properties was performed by averaging the solutions of boundary value problems on representative volume cell (RVC) using the finite element method (FEM). A new approach of calculation of components of effective tensor of elastic moduli was proposed. A heterogeneous finite element model with elements of two types was built: three-dimensional tetrahedron elements for every phases and spring element with zero-length for adhesion layer with zero-thickness. The results of homogenization of elastic properties of dispersedly-reinforced composites with variable stiffness of the adhesive layer between phases were obtained and analyzed. The homogenization results were compared with the available experimental data.
The Fabrication of Titanium Dioxide-Tin Oxide/Reduced Graphene Oxide Photoanodes for Dye-Sensitized Solar Cells
Authors: Loryuenyong Vorrada , Jindawattanawong Bodin , Jaroenkun Panpaporn , Supannakool Apichat , Buasri Achanai
Published: September 2018

This research studied the preparation of titanium dioxide (TiO2) composite films with the incorporation of tin oxide and reduced graphene oxide (SnO2-RGO) for uses as photoanodes in dye-sensitized solar cells (DSSCs). The experimental procedure started with the synthesis of graphene oxide by Hummer's method, followed by the preparation of SnO2-RGO composite materials by hydrothermal process. The resultant SnO2-RGO was sequentially mixed with TiO2 to prepare the composite films by doctor-blade method. The results indicated that the addition of graphene oxide into SnO2 could reduce the band gap, avoid the agglomeration, and improve the dispersion of tin oxide particles (SnO2). According to the efficiency tests of the obtained photoanodes, a small amount of RGO could significantly affect the DSSC’s performance. Without RGO, TiO2-SnO2 photoanodes exhibited very poor performance. This could be due to low dye-adsorption capability and low electron transfer ability. The addition of excess amount of RGO in photoanode could, however, lead to negative effects such as charge trapping and lower solar cell efficiency.
Highly Tm Doped Silica Optical Preform by MCVD - Chelate Vapor Delivery (Soot-Dopant Stepwise Technique)
Authors: Mat-Sharif K.A. , Omar Nasr Y.M. , Zulkifli M.I. , Muhd-Yassin S.Z. , Sin Y.K. , Abdul-Rashid H.A. , Tamchek N.
Published: September 2018

This paper presents the progress in the fabrication of highly doped thulium silica fiber. As much as 5.3 wt. % Tm alongside 7.1 wt. % Al (co-dopant) were incorporated into silica preform. The preform was fabricated using the Modified Chemical Vapor Deposition (MCVD)-chelate vapor delivery with soot-dopant stepwise technique. The preform was analyzed for several key properties such as refractive index variation along deposition length, dopants distribution profiles and UV-Vis absorption. The results showed a homogeneous dopants distribution with 4% RSD in the longitudinal refractive index along a 40 cm preform length. The UV-Vis absorption spectrum exhibited a strong absorption peak at 790 nm attributed to Tm 3H4 energy manifold.
Characterization of Crystalline Cu2SnS3 Synthesized via Low Temperature Solvothermal Method
Authors: Latif Mohamed S. Abdel , Shaalan Dr. Nagih , El-Moneim Ahmed Abd
Published: September 2018

Cu2SnS3 flower-like nanoparticles consisted of nanoflakes were successfully produced using solvothermal technique at 120°C for 12 h. The precursors used in this process were CuCl2.2H2O, SnCl2.2H2O, and thiourea with dimethyl sulfoxide (DMSO) as a solvent. The results showed that the as-obtained product was triclinic Cu2SnS3 with secondary phases CuS and SnS, and after annealing process, a pure triclinic was obtained. The crystal structure of the obtained samples was investigated by X-ray diffraction which assured the obtained data and the average crystallite size of as-prepared and annealed CTS was found to be 18.42 and 31.6 nm, respectively. Scanning electron microscopy (SEM) showed that the surface morphology has the shape of flower like consisted of nanoflakes. The transmission electron microscope (TEM) displayed the formation of sheets. The band gap was measured using UV-Vis absorption spectroscopy and found that the as-prepared sample has 1.97 eV band gap, which obtained for various phases CuS and SnS. However, this band was changed to 1.26 eV upon the heat treatment at 500°C for 10 minutes. This value of Eg is comparable with the value reported by other literatures.
Manufacturing Refractory Bricks Using Exhaust Dust from Foundry Industries
Authors: dos Santos Antonio Vanderlei , Przyczynski Renato , Anibele Tatieli Pivoto , Marchetti Mauro Cesar
Published: September 2018

The exhaust dust is an industrial waste that results from the sand molded casting process in the foundry sector. The metal casting industry plays an important role in the reduction of the environmental impact by recycling industrial waste. The idea of manufacturing thermally resistant refractory bricks made of exhaust dust from the foundry industry has motivated managers and researchers. The purpose of this study is to analyze the manufacturing process of refractory bricks made of 10, 20 and 30% exhaust dust and their properties. The dust was analyzed by using the SEM/EDX and XRD techniques. Results show that the specimens used in this study did not meet the required water absorption specifications. However, the 10% and 20% samples presented a desirable porosity. The manufactured bricks were classified as dense, insulating and semi-insulated, respectively. In relation to compression resistance the rupture stress proved to be lower than the level of stress detected in commercial bricks. The temperature test showed that bricks made of exhaust dust cannot be considered refractory for commercial purposes. Although the exhaust dust does have some refractory properties it still cannot be used as raw material in the manufacturing of refractory bricks since it does not meet all the necessary specifications as proposed by this study.
Characterization of Bamboo Charcoal Prepared Using Oil Barrel Kiln
Authors: Yordsri Visittapong , Thanachayanont Chanchana , Junin Chabaiporn , Keratipaiboon Nuttakorn , Tabai Pairat , Rodchom Mana , Jongthammanurak Samerkhae , Ninwilai Phetcharaporn , Seraphin Supapan , Boothroyd Chris
Published: September 2018

Charcoal consists mostly of carbon materials prepared by carbonization, i.e., traditionally by pyrolysis [1,2] of wood pieces in a kiln. At a high enough temperature and an absence of oxygen [3], high-quality charcoal with low resistance can be produced. A possible application of the low-resistivity charcoal is as an electrode material for electrochemical devices. In this research, bamboo waste was used to produce low-resistance bamboo charcoal. During heating, the temperature gradually increased up to 700°C, was kept approximately constant overnight, and was left to cool down to room temperature. Then, the charcoal bamboo pieces were obtained. A rough temperature-resistivity map was constructed. The bamboo charcoals were divided into 3 resistivity ranges, namely, 20, 100 and 1000 ohm.cm-1. Transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy and microEDX (energy dispersive X-ray spectroscopy), were conducted for charcoal morphology and spectroscopic characterization [4-6]. The morphological results from SEM did not show any significant differences among bamboo charcoals with different resistivity. DF-STEM and EDS-STEM mapping revealed impurities inside the bamboo charcoal. Elemental analysis of micro areas showed weight percentage of carbon and other impurities in the bamboo charcoals. The 20 ohm.cm-1 bamboo charcoal was the best among all resistivity studied in terms of purity and main carbon structure. Decreasing the impurity content was found to be one of the essential parameters to obtain low resistivity bamboo charcoal. It was concluded that improving the stability and condition of the burning process in the conventional kiln was necessary in order to get a high yield of low resistance bamboo charcoals.
Effects of Sintering Temperature on Phase, Physical Properties and Microstructure of Ca3Co4O9 Ceramic
Authors: Wannasut Pimpilai , Prayoonphokkharat Poom , Keawprak Nittaya , Jaiban Panupong , Watcharapasorn Anucha
Published: September 2018

This study investigated the effects of sintering temperature on phase, physical properties and microstructure of calcium cobalt oxide (Ca3Co4O9 or CCO) ceramic. CCO powder was prepared with using the mixed oxide method and calcined at 750°C for 24 h. The ceramics were prepared by sintering the powder at 900, 950, 1000 and 1050°C under a normal air atmosphere for 24 h. A maximum density of 4.02 g/cm3 (~92% relative density) with 12% linear shrinkage was obtained in the sample sintered at 1000°C. XRD patterns of the CCO ceramics indicated pure phase with no detected impurity. SEM images of the ceramics showed plate-like shaped grains. The average grain size value gradually increased as the sintering temperature increased, and reached a maximum value of 8.95 mm at the sintering temperature of 1000°C. The deviation from stoichiometric composition for the samples sintered at low sintering temperatures may be due to the low sample density which in turn affected the EDS analysis results.
Microscopy and Microanalysis of Zinc-Magnesium Alloys Related to Their Microhardness and Electrochemical Behavior in KOH Solution
Authors: Nusen Sankum , Komboonchoo Sunsanee , Yottawee Noppadol , Chairuangsri Torranin
Published: September 2018

Zn-Mg alloys containing up to 5.28 wt.%Mg were prepared by gravity casting. Light and scanning electron microscopy with energy-dispersive X-ray spectrometry were used to characterize their as-cast microstructure as compared to that of pure zinc. The alloy with 3.60 wt.%Mg was found to be eutectic. Phase identification by X-ray diffractometry suggested that the eutectic Mg-rich phase wasMg2Zn11 with two types of intermetallic compounds, including Mg2Zn11 and MgZn2, present in the alloy with 5.28 wt.%Mg. The microhardness increased with increasing Mg content from 41 HV for pure zinc to 266 HV for the alloy with 5.28 wt.%Mg. The electrochemical behavior of the alloys was studied by potentiodynamic polarization test at room temperature using 8.5 M KOH solution as electrolyte. Hydrogen evolution was generally postponed for the cases of Zn-Mg alloys as compared to pure zinc. The corrosion potential (Ecorr) was not significantly affected by Mg addition into Zn, while the corrosion current density (icorr) was significantly increased, especially for the case of the alloy with 3.60 wt.%Mg, as compared to that of pure zinc. It can be proposed that, due to its relatively higher hydrogen overpotential and uniform corrosion in KOH solution, the eutectic alloy with 3.60 wt.%Mg can be an alternative to pure zinc for use as anode in applications related to alkaline electrolyte.
Microstructure and Tempering Behaviour of 28Cr-2.5C-1W Cast Irons
Authors: Yeekew Sasitorn , Wiengmoon Amporn , Chairuangsri Torranin , Pearce John T.H.
Published: September 2018

In this work, the effects of 1 wt.% tungsten addition and variation in tempering times on the microstructure and hardness of nominal 28 wt.%Cr high chromium irons were investigated. As-cast samples were destabilised at 1050 °C for 4 hours and then hardened by air cooling. Tempering after destabilisation was carried out at 450 °C for 2, 4 and 6 hours followed by air cooling. X-ray diffractometry, light microscopy and scanning electron microscopy were used to characterize the microstructures of the irons. The results show that the as-cast microstructure of the iron without W addition consisted of primary austenite dendrites with eutectic M7C3 and eutectic austenite partially transformed to martensite. The iron with 1 wt.%W addition contained primary M7C3 and eutectic M7C3 in an austenite matrix. Destabilisation treatment of the austenite matrix in both irons allowed precipitation of secondary carbides and transformation to martensite during air cooling. Phase transformation of eutectic M7C3 was also found in the iron with W addition. The formation of primary M7C3 in the 1 wt.%W iron increased the as-cast macro-hardness from 500 (no W) to 576 HV30. Destabilisation increased the macro-hardness up to 736 (no W) and 780 HV30 (1 wt.%W) since secondary carbide precipitation allowed austenite to transform to essentially martensitic matrices. At longer tempering times, the macro-hardness further increased up to about 820 HV30.
Physical, Dielectric Properties and Micro-Hardness of the (Ba0.90Ca0.10)0.90(Na0.50Bi0.50)0.10TiO3 Ceramics Prepared by Molten Salt Method
Authors: Warangkanagool Chompoonuch
Published: September 2018

In this study, the physical properties, dielectric properties, and micro-hardness of (Ba0.90Ca0.10)0.90(Na0.50Bi0.50)0.10TiO3 or BCT-NBT ceramics prepared by molten salt method with various sintering temperatures were investigated. The powders were calcined at 500-1100°C for 4 h with heating rate of 5°C/min. It was found that the optimum calcination condition was 1000°C for 4 h. These powders were pressed and sintered at 1200-1400°C for 3 h with a heating rate of 5°C/min. The microstructure was examined by scanning electron microscope (SEM). The density of the sintered samples was measured by Archimedes method with distilled water as the fluid medium. Dielectric properties were examined by LCR meter. The micro-hardness of the BCT-NBT ceramics was determined using the Vickers and Knoop indentation techniques. The results showed that the average grain sizes increased with increasing sintering temperatures. At sintering temperatures higher than 1200°C, the fracture mode changed from partial intra-granular to mainly intra-granular. The sintering temperature at which the density, dielectric and hardness properties were maximal was 1350°C. The highest density was about 5.4 g/cm3, and the Vickers and Knoop micro-hardnesses were 6.6 and 6.4 GPa, respectively. The dielectric constant at the Curie temperature was 3682 and the dielectric loss was 0.01 at 1 kHz frequency.