Development of sputtered techniques for thrust chambers

Procedures for closing out coolant passages in regeneratively cooled thrust chambers by triode sputtering, using post and hollow Cu-0.15 percent Zr cathodes are described. The effects of aluminum composite filler materials, substrate preparation, sputter cleaning, substrate bias current density and system geometry on closeout layer bond strength and structure are evaluated. High strength closeout layers were sputtered over aluminum fillers. The tensile strength and microstructure of continuously sputtered Cu-0.15 percent Zr deposits were determined. These continuous sputtered deposits were as thick as 0.75 cm. Tensile strengths were consistently twice as great as the strength of the material in wrought form

Design and evaluation of a framework for cooperative and adaptive QoS control of DSRC network for road safety applications

Dedicated short-range communications (DSRC) are a promising vehicle communication technique for collaborative road safety applications (CSA). However, road safety applications require highly reliable and timely wireless communications, which present big challenges to DSRC based vehicle networks on effective and robust quality of services (QoS) provisioning due to the random channel access method applied in the DSRC technique. In this paper we examine the QoS control problem for CSA in the DSRC based vehicle networks and presented an overview of the research work towards the QoS control problem. After an analysis of the system application requirements and the DSRC vehicle network features, we propose a framework for cooperative and adaptive QoS control, which is believed to be a key for the success of DSRC on supporting effective collaborative road safety applications. A core design in the proposed QoS control framework is that network feedback and cross-layer design are employed to collaboratively achieve targeted QoS. A design example of cooperative and adaptive rate control scheme is implemented and evaluated, with objective of illustrating the key ideas in the framework. Simulation results demonstrate the effectiveness of proposed rate control schemes in providing highly available and reliable channel for emergency safety messages

Mixing-induced anisotropic correlations in molecular crystalline systems

We investigate the structure of mixed thin films composed of pentacene (PEN) and diindenoperylene (DIP) using X-ray reflectivity and grazing incidence X-ray diffraction. For equimolar mixtures we observe vanishing in-plane order coexisting with an excellent out-of-plane order, a yet unreported disordering behavior in binary mixtures of organic semiconductors, which are crystalline in their pure form. One approach to rationalize our findings is to introduce an anisotropic interaction parameter in the framework of a mean field model. By comparing the structural properties with those of other mixed systems, we discuss the effects of sterical compatibility and chemical composition on the mixing behavior, which adds to the general understanding of interactions in molecular mixtures.Comment: 5 pages, 5 figures, accepted by Phys. Rev. Let

Alterações em atributos físicos do solo decorrentes da rotação soja-pastagem, no sistema plantio direto.

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Design of the laboratory script by the students in chemistry practicals: Analysis of water

Comunicació presentada a INTED2018, 12th International Technology, Education and Development Conference. (March 5-7, 2018, Valencia, Spain).The laboratory practices during the Degree in Chemistry are currently designed so that the student must learn and execute a fully developed experimental protocol, previously written up by the professor, which contains all the information and requirements for the correct development of each laboratory session. Under these conditions, students do not need to take any initiative and, consequently, they do not put enough effort in reaching practical abilities with a well-based scientific criterion and do not try to think over the purpose of each lab operation, as well as the reason to use each material and/or each reagent. Thus, with the aim to promote a more active role of the students in their learning process and to improve their autonomy, a new laboratory practices design has been developed in this work, which follows methodologies on project-based cooperative learning: the students have been requested to elaborate themselves the laboratory script by pairs. With this innovative design, we pursue to involve the students in both elaboration and execution steps of the laboratory practicals, and then to increase their attention on them. Besides, the required bibliographic research would improve their knowledge about the studied topic and all aspects about the work at the laboratory. The practicals to-be-developed were related to the study of the physico-chemical quality of natural water, which has a high social relevance

Management of diversity in master classroom: an increasing challenge for science education in valencian universities

Comunicació presentada a INTED2018, 12th International Technology, Education and Development Conference. (March 5-7, 2018, Valencia, Spain).Currently, many foreign students study a Master degree at the Valencian Universities. We can find students, which have immigrated to Spain in the recent years, and then have partially or fully follow the Spanish curricula (High School and/or Grade), and others which have come specifically to study the Master, attracted by the reputation of the Universities and the job and way-of-life offered by the country, and then have achieved their Grade in their countries. This has increased the diversity of the students in the classrooms, related to the ethnic origin, mother language, study practices, background and integration in the society. The present work gives an overview on how students and teacher manage the heterogeneity and diversity in a Master classroom related to chemistry. The term “diversity” is first detailed prior to discussing explicit studies. Different aspects of diversity are stated. The personal experience of the foreign students to adapt to the Spanish courses and environment was investigated. The actions taken by the lecturer to take advantage of diversity and minimize its negative effects were examined. A comparison between the academic results obtained by international and national students is given. Finally, the attention will be focused on language, study practices and background, since these dimensions are frequently discussed in the Valencian context. The implications and opportunities that offer diversity for national but also for international science research are presented

High submicellar liquid chromatography

Surfactant addition above the critical micellar concentration (CMC), in reversed-phase liquid chromatography (RPLC), was proposed as a way to modify the selectivity and analysis time, giving rise to a chromatographic mode called micellar liquid chromatography (MLC). However, solutions containing only surfactant are too weak and yield poor peak shape. This was remediated by the addition of a small amount of organic solvent. To preserve the existence of micelles, in MLC high contents of organic solvent are avoided. Nevertheless, there is no reason to neglect the potentiality of mobile phases containing a surfactant above its CMC in water and a high organic solvent content (without micelles). This chromatographic mode has been called high submicellar liquid chromatography (HSLC). Several reported procedures show that the combination of stronger elution strength, larger selectivity and improved peak shape, with respect to MLC and conventional RPLC, makes HSLC a promising chromatographic mode to achieve in practical times separations of compounds unresolved or highly retained with other RPLC modes. Some insights on the interactions that occur inside the chromatographic column, the modification of the stationary and mobile phases, retention modeling, and chromatographic performance in HSLC are here offered, in comparison to MLC and conventional RPLC

Implantación de las buenas prácticas de laboratorio en la asignatura "Química para las Ingenierias" en la Universitat Jaume I

Comunicación presentada en la V Jornada Nacional sobre Estudios Universitarios, celebrades en la Universitat Jaume I (Castellón, España), los dies 12 y 13 de Noviembre de 2015.En el presente artículo, se detalla la implementación de las Buenas Prácticas de Laboratorio (BPL) en el laboratorio de la asignatura «Química para las Ingenierías» (EX1006), impartida en varios grados de ingeniería (Agroalimentaria y del Medio Ambiente, Mecánica, Eléctrica, Tecnologías Industriales y Química) de la Universitat Jaume I. Las BLP son un conjunto de normas y procedimientos operativos acerca de la forma adecuada de organizar y trabajar en el laboratorio en una amplia variedad de disciplinas científicas, incluida la química. El principal objetivo de las BPL es asegurar la fiabilidad, estabilidad y calidad de los resultados. Para ello, se indica cómo el procedimiento experimental debe ser planificado, ejecutado, supervisado, anotado, registrado y archivado. Asimismo, proporciona recomendaciones para la gestión del laboratorio, en especial para minimizar el vertido de residuos tóxicos, e incrementar la seguridad laboral en el laboratorio. Varias organizaciones y agencias internacionales (industria farmacéutica, la Organización para la Cooperación y el Desarrollo Económicos, US Food and Drug Administration y la Comisión Europea), han desarrollado y promulgado varios conjuntos de normas BLP. La Universitat Jaume I considera que un conocimiento profundo y una aplicación adecuada de las BPL son muy importantes para desarrollar un trabajo correcto en el laboratorio químico. Por ello, los estudiantes de química deben ser conscientes desde el primer curso académico de su relevancia, así como conocer las normas principales y la forma de aplicarlas en el laboratorio. Por ello, las BPL se han incluido en la guía docente de la asignatura de Laboratorio de Química para las Ingenierías (1er curso académico) Además, los profesores deben centrarse en las BLP al impartir la docencia, para un correcto aprendizaje por parte de los estudiantes. Se requirió a los estudiantes que evaluasen el proceso de implantación y mostrasen su grado de aceptación de las BPL, mediante un cuestionario global de la asignatura. Como resultado final, se puede remarcar que los estudiantes comprendieron la utilidad de las BPL y la importancia de conocerlas para su futuro laboral, así como la necesidad de su inclusión en la guía docente de las asignatura de laboratorios de química