bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental and theoretical approaches on thermal and structural properties of Zn doped BSCCO glass ceramics
Authors: Koralay H. , Hicyilmaz O. , Cavdar S. , Ozturk O. , Tasci A.T. 
Published: April 2016

AbstractThermal properties of Cu–Zn partially substituted Bi1.8Sr2Ca2Cu3.2-xZnxO10+δ(x = 0, 0.1 and 0.5) glass-ceramic systems have been investigated with the help of a differential thermal analyzer (DTA) by using Johnson-Mehl-Avrami-Kolmogorov (JMAK) approximation. Non-isothermal crystallization kinetics of the samples has been tested. The calculated values of activation energy of crystallization (E) and Avrami parameter (n) ranged between 306.1 and 338.3 kJ.mol-1and 1.29 and 3.59, respectively. Crystallization kinetics was compared following the partial substitution, before and after Zn doping of the sample. In addition, by using a scanning electron microscope (SEM) and X-ray powder diffractometer (XRD), structural properties of Zn doped BSCCO glass-ceramic samples were determined. Surface morphology of the samples was studied by SEM measurements. Lattice parameters and volume of the samples were calculated from the XRD measurements.
Colloidal nanocrystals for quality lighting and displays: milestones and recent developments
Authors: Erdem Talha , Demir Hilmi Volkan 
Published: April 2016

AbstractRecent advances in colloidal synthesis of nanocrystals have enabled high-quality high-efficiency light-emitting diodes, displays with significantly broader color gamut, and optically-pumped lasers spanning the whole visible regime. Here we review these colloidal platforms covering the milestone studies together with recent developments. In the review, we focus on the devices made of colloidal quantum dots (nanocrystals), colloidal quantum rods (nanorods), and colloidal quantum wells (nanoplatelets) as well as those of solution processed perovskites and phosphor nanocrystals. The review starts with an introduction to colloidal nanocrystal photonics emphasizing the importance of colloidal materials for light-emitting devices. Subsequently,we continue with the summary of important reports on light-emitting diodes, in which colloids are used as the color converters and then as the emissive layers in electroluminescent devices. Also,we review the developments in color enrichment and electroluminescent displays. Next, we present a summary of important reports on the lasing of colloidal semiconductors. Finally, we summarize and conclude the review presenting a future outlook.
Quantum Cascade Laser Frequency Combs
Authors: Faist Jérôme , Villares Gustavo , Scalari Giacomo , Rösch Markus , Bonzon Christopher , Hugi Andreas , Beck Mattias 
Published: April 2016

Abstract
It was recently demonstrated that broadband quantum cascade lasers can operate as frequency combs. As such, they operate under direct electrical pumping at both mid-infrared and THz frequencies, making them very attractive for dual-comb spectroscopy. Performance levels are continuously improving, with average powers over 100mW and frequency coverage of 100 cm-1 in the mid-infrared region. In the THz range, 10mW of average power and 600 GHz of frequency coverage are reported. As a result of the very short upper state lifetime of the gain medium, the mode proliferation in these sources arises from four-wave mixing rather than saturable absorption. As a result, their optical output is characterized by the tendency of small intensity modulation of the output power, and the relative phases of the modes to be similar to the ones of a frequency modulated laser. Recent results include the proof of comb operation down to a metrological level, the observation of a Schawlow-Townes broadened linewidth, as well as the first dual-comb spectroscopy measurements. The capability of the structure to integrate monothically nonlinear optical elements as well as to operate as a detector shows great promise for future chip integration of dual-comb systems.
Advancing colloidal quantum dot photovoltaic technology
Authors: Cheng Yan , Arinze Ebuka S. , Palmquist Nathan , Thon Susanna M. 
Published: April 2016

Abstract Colloidal quantum dots (CQDs) are attractive materials for solar cells due to their low cost, ease of fabrication and spectral tunability. Progress in CQD photovoltaic technology over the past decade has resulted in power conversion efficiencies approaching 10%. In this review, we give an overview of this progress, and discuss limiting mechanisms and paths for future improvement in CQD solar cell technology.We briefly summarize nanoparticle synthesis and film processing methods and evaluate the optoelectronic properties of CQD films, including the crucial role that surface ligands play in materials performance. We give an overview of device architecture engineering in CQD solar cells. The compromise between carrier extraction and photon absorption in CQD photovoltaics is analyzed along with different strategies for overcoming this trade-off. We then focus on recent advances in absorption enhancement through innovative device design and the use of nanophotonics. Several light-trapping schemes, which have resulted in large increases in cell photocurrent, are described in detail. In particular, integrating plasmonic elements into CQD devices has emerged as a promising approach to enhance photon absorption through both near-field coupling and far-field scattering effects. We also discuss strategies for overcoming the single junction efficiency limits in CQD solar cells, including tandem architectures, multiple exciton generation and hybrid materials schemes. Finally, we offer a perspective on future directions for the field and the most promising paths for achieving higher device efficiencies.
Crystal structure of 1α,7β-dihydroxy-11β-acetoxy-ent-7β,20-epoxykaur-16-en-15-one, C22H30O6
Authors: Liu Ya-Hua , Zhang Jing-Jie , Ye Jiang-Hai , Zhao Chen-Liang , Pan Lu-Tai 
Published: April 2016

Abstract
C22H30O6, orthorhombic, P212121 (no. 19), a = 5.979(4) Å, b = 16.735(12) Å, c = 20.323(15) Å, V = 2034(3) Å3, Z = 4, R
gt
(F) = 0.0498, wR
ref
(F
2
) = 0.1209, T = 293(2) K.
Crystal structure of 7β,14β,15β-trihydroxy-1α-acetoxy-7α,20-epoxy-ent-kaurane, C22H32O6
Authors: Lv Jun , Ye Jiang-Hai , Yang Li-Yong , Zhao Chen-Liang , Zhang Jing-Jie , Pan Lu-Tai 
Published: April 2016

Abstract
C22H30O6, monoclinic, P21 (no. 14), a = 9.111(3) Å, b = 9.535(3) Å, c = 11.331(4) Å, β = 92.703(4)°, V = 983.3(5) Å3, Z = 2, R
gt
(F) = 0.0418, wR
ref
(F
2) = 0.1152, T = 293 K.
Microencapsulación de aceite esencial de tomillo (Thymus vulgaris) en matrices poliméricas de almidón de ñame (Dioscorea rotundata) modificado
Authors: Matiz Melo Germán Eduardo , Fuentes López Katerin , León Méndez Glicerio 
Published: April 2016

<p>Los aceites esenciales son conocidos por sus numerosas actividades biológicas y organolépticas, pero su empleo suele verse limitado por su alta volatilidad y tendencia a degradarse. La microencapsulación es una estrategia válida para superar estos inconvenientes. En este trabajo se empleó almidón de ñame (D. rotundata), el cual fue sometido a procesos de hidrólisis y lipofilización, empleando anhídrido dodecenilsuccínico (DDSA); esto incrementó significativamente las capacidades captadora de aceite y emulsificante (tensoactiva) del almidón nativo, el cual se empleó para microencapsular aceite esencial de tomillo, que en estudios previos demostró potente actividad antibacteriana sobre las cepas involucradas en el desarrollo del acné. La microencapsulación se llevó a cabo por microparticulación lipídica sólida, seguida de emulsificación. Esta alcanzó una eficiencia superior al 98%, y el producto obtenido, desafiado en diversas pruebas, demostró capacidad de retener más del 90% del aceite esencial en condiciones de evaporación, evitando su oxidación y el cambio en su perfil de composición. Finalmente, las microcápsulas de aceites esenciales de tomillo, al ponerse en contacto con las bacterias del acné, mantuvieron su actividad bactericida. Los resultados de este trabajo aportan al desarrollo de formulaciones farmacéuticas, cosméticas y alimentarias estables y funcionales de aceites esenciales, al protegerlos de la evaporación y degradación.</p>
Estudio matemático de estabilidad del estado estacionario del desempeño del electrodo de la pasta de carbono, químicamente modificado por un líquido iónico, en la cuantificación del galato de propilo
Authors: Tkach Volodymyr V. , Ferreira Valdir Souza , Ojani Reza , Galeano Espínola Michel O. , Yagodynets’ Petró I. , De Rizzo da Matta Márcia H. 
Published: April 2016

<p>El comportamiento y el desempeño electroquímico del electrodo de pasta de carbono químicamente modificado por un líquido iónico (EPCQM), en la detección del galato de propilo, se investigaron matemáticamente desde el punto de vista de la estabilidad del estado estacionario. El modelo matemático correspondiente se analizó por medio de la teoría de estabilidad lineal y análisis de bifurcaciones. Los resultados de modelaje son comparados con los experimentales (para este sistema y<br />semejantes), bien como con los teóricos para otros casos.</p>
Conocimientos, actitudes, prácticas y educación sobre tuberculosis en estudiantes de una facultad de salud
Authors: Wilches Luna Esther Cecilia , Hernández Nasly Lorena , Hernández Orobio Olga Marina , Pérez Vélez Carlos Mario 
Published: April 2016

<p>Determinar los conocimientos, actitudes, prácticas y educación relacionados con Tuberculosis, así como la reactividad a la prueba cutánea de tuberculina de estudiantes de último año de una facultad de salud.</p><p><strong>Método</strong> Se realizó un estudio transversal utilizando un cuestionario diseñado y validado por los investigadores para indagar los conocimientos, actitudes, prácticas y educación relacionados con tuberculosis en 193 estudiantes de último año de los programas de medicina, enfermería, odontología, fisioterapia, fonoaudiología, terapia ocupacional, laboratorio clínico y atención pre-hospitalaria. Se realizó la prueba cutánea de tuberculina en 153 de los encuestados.</p><p class="MsoNormal" style="text-align: justify; line-height: 150%;"><strong>Resultados</strong> Aunque la mayoría de los encuestados calificaron como suficiente la educación recibida sobre tuberculosis, los resultados sobre conocimientos no apoyan esta percepción: 35,2 % de los estudiantes no identificaron apropiadamente los factores de riesgo para tuberculosis nosocomial, solo 33,7 % conocían la incidencia de tuberculosis en el país y un 1,6 % de los encuestados identificó apropiadamente el tratamiento de primera línea para tuberculosis. En cuanto a las prácticas, un 50 % de los encuestados admitió que realizaría la atención de un paciente con tuberculosis sin máscara de alta eficiencia. De acuerdo a la prueba cutánea de tuberculina, 35 % de los estudiantes tenía tuberculosis latente.</p><p class="MsoNormal" style="text-align: justify; line-height: 150%;"><strong>Conclusiones</strong> Los resultados indican que existen oportunidades para mejorar la educación que reciben los estudiantes de esta facultad con respecto a la tuberculosis, además es necesario mejorar las medidas de protección en los contextos en que se llevan a cabo las prácticas de los estudiantes para reducir el riesgo de conversión.</p>
Seroprevalencia de anticuerpos a virus del sarampión, rubeola, parotiditis, hepatitis B y los tres serotipos de poliovirus, en niños de Quindío, Colombia
Authors: Gonzalez de Sch María Mercedes , Giraldo Garcia Alejandra María , Padilla Sanabria Leonardo , Sarmiento Perez Luis , Rey-Benito Gloria Janneth , Castaño Jhon Carlos 
Published: April 2016

<p>Determinar la seroprevalencia de anticuerpos a virus de sarampión, rubeola, parotiditis, hepatitis B y los tres serotipos de poliovirus en población infantil del Departamento del Quindío, Colombia.</p><p><strong>Métodos</strong> Se colectaron muestras de sangre de 170 niños en edades comprendidas entre los cinco y nueve años de nueve departamentos del Quindío. Se determinó la presencia de anticuerpos tipo IgG para sarampión, rubeola y parotiditis mediante un ELISA indirecto comercial. La inmunidad contra la poliomielitis se determinó por la presencia de anticuerpos neutralizantes a poliovirus según los métodos recomendados por OMS.</p><p><strong>Resultados </strong>De los 170 niños estudiados, 169 (99,41 %), 170 (100 %), and 167 (98,2 %) fueron seropositivos a poliovirus 1, poliovirus 2, y poliovirus 3, respectivamente. El título promedio geométrico de anticuerpos fue 178 para poliovirus tipo 1, 120 para el tipo 2 y 56 para el tipo 3. De los 170 niños, el 96,47 % estuvo protegido contra parotiditis y rubeola y el 86,47 % contra sarampión. Se demostró respuesta serológica positiva contra el virus de la hepatitis B solamente en el 62,35 % de las muestras.</p><p><strong>Conclusiones</strong> El programa de inmunización en el Quindío permitió la seroprotección contra los tres serotipos de la polio, rubeola y parotiditis. Sin embargo, la población infantil no está completamente protegida contra la infección con sarampión y virus de la hepatitis B.</p>
Tecnologías de internet (de Arpanet a la 3G)
Authors: López Rubio Gustavo 
Published: April 2016

A pesar de que Internet es una herramienta ampliamente utilizada, su conocimiento técnico queda reducido a ingenieros y profesionales de telecomunicación y tecnologías de información. Por eso, su funcionamiento, "grosso modo", supone una gran laguna para la mayor parte de las personas que la utilizan, aunque lo hagan frecuentemente. Tal vez esto sea debido a que "Internet es fácil de usar pero difícil de comprender".1 y como para comprender algo es preciso conocerlo previamente, cabe preguntarse:
¿Qué es Internet? Una buena respuesta nos la da Harley Hahn: "¿Es posible que haya un impulso biológico que nos incite a crear computadoras? Creo que no. Pero una vez hemos desarrollado estos extraños y maravillosos esclavos, lo más seguro es que haya un programa genético irresistible que nos invita a continuar. En nuestro interior, hay una voz que oímos sólo subconscientemente y sólo como una especie; una voz que nos ordena tomar estas computadoras, conectarlas mediante redes y (...) comunicarnos.
Esto nos lleva a la segunda idea: cuando conectamos computadoras, indudablemente estamos creando algo que es mucho más importante que la suma de sus partes. Como hemos dicho, Internet se compone de millones de personas, pero 1as computadoras no son importantes; las utilizamos, solamente para ejecutar nuestros programas (esto es, para que sigan nuestras instrucciones).
Un análisis provincial comparativo de la localización de actividades profesionales en áreas rurales
Authors: Polo Inmaculada , Paniagua Ángel 
Published: April 2016

Los Servicios a empresas están considerados como la nueva fuente de empleo por la gran flexibilidad que presentan. Estos servicios cubren actividades demandadas desde las muy cualificadas hasta las menos, consiguiendo servicios de gran calidad con gran flexibilidad en la producción y por tanto en el empleo, variables predominantes en el entorno económico actual. El crecimiento de estos servicios se ve potenciado por las distintas actividades laborales nuevas que van surgiendo, orientadas principalmente hacia un trabajo autónomo y distintos proyectos individuales.
Tanto el trabajo autónomo como el teletrabajo es una de las soluciones que se están buscando en los países europeos para intentar reducir los altos índices de desempleo, enfocándolos principalmente a la incorporación al mercado laboral de la mujer, siendo el que más aceptación tiene el trabajo a tiempo parcial (Rubalcaba, 2001).
Las distintas oportunidades de empleo varían según el tipo de país con diferencias notables en relación a las condiciones del mercado laboral, factores culturales y trabajo autónomo. Como han indicado Hoggart y Paniagua (2001), durante el período 1995-
1999 el crecimiento total del número de empresas en España subió hasta el 9,5% en lugares con menos de 10.000 habitantes comparado con el 8,7% de los grandes núcleos. No hay una gran diferencia aquí, pero para compañías de los sectores profesional y servicios las cifras fueron 41,3% y 27,3%.
Sensory and Quality Evaluation of Mayonnaise and its Effect on Storage Stability
Authors: Pradhananga Mahalaxmi , Adhikari Babita 
Published: April 2016

This study aimed to evaluate the addition of skim milk powder to replace egg yolk in preparation of mayonnaise. Egg yolk was pasteurized at 150ºF (65.6ºC) about 1 minute for its safety. Mayonnaise was prepared from sunflower oil with the level varied from 65-75% and egg yolk from 9-15%. Mayonnaise made from 70% oil and 12% egg yolk was found to be best. Then skim milk powder (SMP) was added to replace 12% egg yolk in the ratios 0:100, 25:75, 50:50, 75:25 and 100:0 other constituents remaining constant. Sensory evaluation demonstrated that mayonnaise substituted with 25% skim milk powder was best. The chemical composition of the product, as well as fatty acid composition and peroxide value was analyzed. Coliform and Salmonella was not detected in microbial analysis. Sensory studies for its storage stability confirmed that the product was acceptable up to 28th days at refrigerate temperature whereas sample stored in room temperature was deteriorated after 14th days. Sunsari Technical College Journal 2015, 2(1):48-53
Investigation of resistance spot welds between DP450 steel and aluminum alloys
Authors: Akinay Yuksel , Hayat Fatih 
Published: April 2016

Abstract
In this study, the resistance spot weldability of DP450 steel and aluminum alloys (AA1050, AA6061 and AA7075) was investigated and the interfacial characteristics of fracture zones was examined via microanalysis, scanning electron microscopy and energy dispersive spectroscopy (EDX). In addition, tensile shear load tests and hardness tests were performed to determine the mechanical properties and fracture behavior of welded joints. These results suggest that the tensile shear strength of the DP450/AA1050 and DP450/AA7075 joints was not affected by the reaction layer formed at the welding interface. This indicates that the spot weldability of DP450/AA6061 is better than DP450/AA1050 and DP450/AA7075 Al alloys.
Effect of Ni on the mechanical behavior of a high-Mn austenitic TWIP steel
Authors: Akinay Yuksel , Hayat Fatih 
Published: April 2016

Abstract
The effect of Ni on the mechanical properties and microstructure of twinning induced plasticity (TWIP) steels were investigated in this study. TWIP 1 (0.6 C, 24 Mn) and TWIP 2 (0.6 C, 24 Mn, 1 Ni) steels were fabricated and annealed at 700, 800 and 900 °C for 150 minutes and then air-cooled. The results revealed that the Ni containing steel (TWIP 2) exhibits a higher yield strength and tensile strength than the steel TWIP 1. Carbide precipitations have been detected in the microstructure of TWIP 1 and TWIP 2 specimens annealed at 700 °C. However, the microstructure of the steel TWIP 1 annealed at 800 and 900 °C was fully austenitic and some grains included twins. It turned out that with the addition of Ni, the formation of twinning decreased in consequence of the annealing at 800 and 900 °C.
Microstructures and properties of Cr–Cu/W–Cu bi-layer composite coatings prepared by mechanical alloying
Authors: Zhang Jiaping , Feng Xiaomei , Shen Yifu , Chen Cheng , Duan Cuiyuan 
Published: April 2016

Abstract
Cr–Cu/W–Cu bi-layer coatings with composite structures were fabricated by means of mechanical alloying. The Cr–Cu layer and the W–Cu layer were deposited successively and the as-synthesized bi-layer coating was made up of an inner Cr–Cu layer and an outer W–Cu layer. Microstructures, chemical and phase compositions of the as-prepared coatings were characterized. The results indicated that the bonding between the inner coating and the substrate was improved with the increase of Cu in the raw powder. The annealing treatment of the inner Cr–Cu layer was beneficial to the bonding between the inner Cr–Cu coating and the outer W–Cu coating layer. Mechanical properties such as microhardness, friction and wear resistance were tested. The as-synthesized coating could effectively improve the hardness and wear resistance of the Cu substrate.
Simulation analysis on impurity distribution in mc-Si grown by directional solidification for solar cell applications
Authors: Ganesan Nagarajan Somi , Manickam Srinivasan , Karuppanan Aravinth , Perumalsamy Ramasamy 
Published: April 2016

Abstract
We carried out global transient simulation of impurity distribution in multi-crystalline silicon grown by directional solidification using appropriate software. Non-metallic impurities such as carbon, nitrogen and oxygen originate from the furnace parts and each impurity atom was segregated into the mc-Si ingot based on their solubility in the crystal. During the solidification process the temperature distribution causes melt fluctuation in the Si melt, which is controlled by applying an external body force that leads to a uniform distribution of impurity atoms. Here the uniform distribution of impurity atoms was obtained by rotating the crucible at 10 rpm and the investigations were also carried out without crucible rotation and with a crucible rotation rate of 3 rpm. In this paper we have analyzed the segregation of non-metallic impurity atoms and chemical reactions between the impurity atoms, wherein three types of simulations were carried out and their results analyzed.
Friction stir welding of foamable AlSi7 reinforced by B4C
Authors: Uzun Arif , Turker Mehmet 
Published: April 2016

Abstract
Friction stir welding was successfully performed on B4C-reinforced foamable AlSi7 materials produced via a powder metallurgy route. Starting materials of 1 wt.% TiH2, 7 wt.% Si and 6 wt.% B4C were mixed with aluminum matrix powder. Mixed powders were then pressed, extruded and rolled for the production of foamable materials. Microstructural and macrostructural examination along with microhardness and tensile tests were performed to evaluate the weld zone characteristics of foamable materials welded by friction stir welding. Tunnels or needle-shaped gaps were observed in the macrostructures of the weld zones of samples joined at 1 250 rpm and 2 000 rpm rotational speeds. Moreover, the rough surface in the welding zone of materials decreased with increasing rotational speed. Defect-free joints were observed for samples at 1 600 rpm rotational and 40 mm min−1 traverse speeds. There was no significant difference between the microstructures of the weld zone and the base material in terms of particle size and distribution. It was observed that the B4C particles in the nugget zone were partly directed or clustered as a result of the physical mixing. Ultimate tensile strength values of B4C-reinforced foamable AlSi7 materials joined by friction stir welding were found to be lower compared to the base material. The maximum ultimate tensile strength of 135 MPa was obtained at a 1 600 rpm rotational speed and 40 mm min−1 traverse speed. The minimum tensile strength in the samples of 95 MPa was obtained at a 1 250 rpm rotational speed and 80 mm min−1 traverse speed. In all welding conditions, the hardness in the nugget zone increased compared to the base material.