A framework for closed-loop supply chains of reusable articles

Reuse practices contribute to the environmental and economical sustainability of production and distribution systems. Surprisingly, reuse closed-loop supply chains (CLSC) have not been widely researched for the moment. In this paper, we explore the scientific literature on reuse and we propose a framework for reusable articles. This conceptual structure includes a typology integrating under the reusable articles term different categories of articles (transportation items, packaging materials, tools) and addresses the management issues that arise in reuse CLSC. We ground our results in a set of case studies developed in real industrial settings, which have also been contrasted with cases available in existing literature.reverse logistics;case studies;closed-loop supply chains;returns managment

Prioritizing Replenishments of the Forward Reserve

Having sufficient inventories in the piece-picking area of a warehouse is an essential condition for warehouse operations. This requires a timely replenishment of the products from a reserve area in case they could run out of stock. In this paper we develop analytical models to arrive at priority rules for these replenishments in case replenishments and order picking are done simultaneously because of time pressure. This problem was observed in a warehouse of a large cosmetics firm. The priority rules are compared by means of simulation and regression. Finally we present the results o

MEGARA main optics opto-mechanics

MEGARA is the future integral-field and multi-object spectrograph for the GTC 10.4m telescope located in the Observatorio del Roque de los Muchachos in La Palma. INAOE is a member of the MEGARA Consortium and it is in charge of the Optics Manufacturing work package. In addition to the manufacturing of 73 elements, the work package includes the opto-mechanics i.e. the opto-mechanical design, manufacture, tests and integration of the complete assembly of the main optics composed by the collimator and camera subsystems. MEGARA passed the Optics Detailed Design Review in May 2013 and will have the Detailed Design Review of the complete instrument early 2014. Here we describe the detailed design of the collimator and camera barrels. We also present the finite elements models developed to simulate the behavior of the barrel, sub-cells and other mechanical elements. These models verify that the expected stress fields and the gravitational displacements on the lenses are compatible with the optical quality tolerances. The design is finished and ready for fabrication

MEGARA Optics: stain removal in PBM2Y prisms

MEGARA is the new integral-field and multi-object optical spectrograph for the GTC. For medium and high resolution, the dispersive elements are volume phase holographic gratings, sandwiched between two flat windows and two prisms of high optical precision. The prisms are made of Ohara PBM2Y optical glass. After the prisms polishing process, some stains appeared on the surfaces. For this, in this work is shown the comparative study of five different products (muriatic acid, paint remover, sodium hydroxide, aqua regia and rare earth liquid polish) used for trying to eliminate the stains of the HR MEGARA prisms. It was found that by polishing with the hands the affected area, and using a towel like a kind of pad, and polish during five minutes using rare earth, the stains disappear completely affecting only a 5% the rms of the surface quality. Not so the use of the other products that did not show any apparent result

Communicative competence: an initial assessment in student teachers

Este artigo tem como objetivo analisar as percepções sobre a competência comunicativa, nas funções de emissor e receptor, dos alunos docentes. Utilizou-se um delineamento descritivo-transversal não experimental com uma amostra de 184 estudantes selecionados por amostragem não probabilística. Um instrumento confiável foi aplicado para identificar as conquistas e limitações nas funções de receptor e emissor por meio da autoavaliação dos sujeitos nas dimensões de subcompetências linguísticas e pragmáticas. Os resultados indicam que as mulheres têm uma percepção um pouco melhor de suas habilidades de comunicação. Os alunos ensino fundamental valorizam,em alguns itens,melhores habilidades linguísticas do que os alunos que estudam na série infantil, além de serem considerados melhores receptores do que emissores. Sugere-se a necessidade de aprofundar a pesquisa e a integração da competência comunicativa nos programas de formação de professores.Este trabajo se propone analizar las percepciones sobre la competencia comunicativa, en las funciones emisor y receptor, de los estudiantes de magisterio. Se usó un diseño no experimental de tipo descriptivo-transversal con una muestra de 184 estudiantes seleccionada mediante un muestreo no probabilístico. Se aplicó un instrumento confiable para identificar los logros y limitaciones en las funciones de receptor y emisor a través de la autovaloración de los sujetos en las dimensiones de las subcompetencias lingüística y pragmática. Los resultados indican que las mujeres tienen una ligera mejor percepción de sus habilidades comunicativas. Los alumnos del grado de maestro de primaria valoran en algunos ítems unas mejores competencias lingüísticas que los alumnos que cursan el grado de infantil, yse consideraren mejores receptores que emisores. Se sugiere la necesidad de profundizar en la investigación e integración de la competencia comunicativa en los programas de formación de maestro.This article aims to analyze the perceptions of communicative competence in the roles of sender and receiver among student teachers. A non-experimental descriptive-cross-sectional design was used, with a sample of 184 students selected through non-probabilistic sampling. A reliable instrument was administered to assess the achievements and limitations in the roles of receiver and sender through self-assessment of the subjects in the dimensions of linguistic and pragmatic sub-competencies. The results indicate that women perceive their communication skills slightly better. In some items, Elementary school students value better linguistic skills than students studying in the preschool series, and they are considered better receivers than senders. Further research and integrating communicative competence into teacher formation programs are suggested

The boomerang returns? Accounting for the impact of uncertainties on the dynamics of remanufacturing systems

Recent years have witnessed companies abandon traditional open-loop supply chain structures in favour of closed-loop variants, in a bid to mitigate environmental impacts and exploit economic opportunities. Central to the closed-loop paradigm is remanufacturing: the restoration of used products to useful life. While this operational model has huge potential to extend product life-cycles, the collection and recovery processes diminish the effectiveness of existing control mechanisms for open-loop systems. We systematically review the literature in the field of closed-loop supply chain dynamics, which explores the time-varying interactions of material and information flows in the different elements of remanufacturing supply chains. We supplement this with further reviews of what we call the three ‘pillars’ of such systems, i.e. forecasting, collection, and inventory and production control. This provides us with an interdisciplinary lens to investigate how a ‘boomerang’ effect (i.e. sale, consumption, and return processes) impacts on the behaviour of the closed-loop system and to understand how it can be controlled. To facilitate this, we contrast closed-loop supply chain dynamics research to the well-developed research in each pillar; explore how different disciplines have accommodated the supply, process, demand, and control uncertainties; and provide insights for future research on the dynamics of remanufacturing systems

Gran Telescopio Canarias observations of an overdense region of Lyman α emitters at z = 6.5

We present the results of our search near the end of the Reionization Epoch for faint galaxies. This has been done using very deep OSIRIS images obtained at the Gran Telescopio Canarias (GTC). Our observations focus around two close, massive Lyman α emitters (LAEs) at redshift 6.5, discovered in the SXDS field within a large-scale overdense region. The total GTC observing time in three medium band filters (F883w35, F913w25 and F941w33) is over 34 h covering 7.0 × 8.5 arcmin2 (or ∼30 000 Mpc3 at z = 6.5). In addition to the two spectroscopically confirmed LAEs in the field, we have identified 45 other LAE candidates. The preliminary luminosity function derived from our observations, assuming a spectroscopic confirmation success rate of 2/3 as in previous surveys, suggests this area is about 2 times denser than the general field galaxy population at z = 6.5. If confirmed spectroscopically, our results will imply the discovery of one of the earliest protoclusters in the Universe, which will evolve to resemble the most massive galaxy clusters today

MEGARA anti-reflective coatings: theoretical and observed throughput estimations

MEGARA is the new integral field unit (IFU) and multi-object (MOS) spectrograph successfully commissioned at Gran Telescopio Canarias, in August 2017. MEGARA provides spectral resolutions R (fwhm) similar to 6000, 12000 and 20000, via volume phase holographic gratings, at very high efficiency in both IFU and MOS modes. In the case of MEGARA main optics and pupil elements optics, the surfaces in contact with air have an anti-reflective (AR) coatings to minimize the Fresnel losses at the interface glass-air. In this work we present the designs and calculation of the total throughput of the optical system based in the transmission measurements of the AR coated witness samples. The results reflect the benefits of having implemented customized AR coatings for the mean angle of incidence on each surface as the measured throughput was better than the requirements. We analyze the effects of the pupil elements AR coatings for each spectral configuration