How far from Just-in-time are Portuguese firms? A survey of its progress and perception.

As competition increases, Just-in-Time (JIT) manufacturing becomes an important issue in Portuguese industry. After a brief review of its history, elements, advantages and limitations, this paper presents the results of a postal questionnaire survey about JIT system sent to a sample of manufacturing firms in Portugal, with the aim of determining the degree of development, perception and status of JIT production in Portuguese industries. The findings suggest that the surveyed firms have a basic JIT perspective: a tool to reduce inventories, to increase quality and to eliminate waste. Despite the good perception of the JIT concept, less than 6% of the firms surveyed have the necessary conditions to successfully implement a JIT system.just-in-time, Portuguese industries, manufacturing

Does Order Negotiation Improve The Job-Shop Workload Control?

Work flows in a job-shop are determined not only by the release load and the time between release factors, but also by the number of accepted orders. There has been extensive research on workload and input-output control aiming at improving the performance of manufacturing operations in job-shops. This paper explores the idea of controlling the workload since the acceptance/rejection of orders stage. A new acceptance/rejection rule is proposed, and tests are conducted to study the sensitivity of job-shop performance to different order acceptance parameters, like the tolerance of the workload limit and the due date extension acceptance. It also evaluates the effect of the negotiation phase of the proposed acceptance rule on the job-shop performance using a simulation model of a generic random job-shop. The extensive simulation experiments allow us to conclude that having a negotiation phase prior to rejection improves almost all workload performance measures. We also conclude that different tolerances of the workload limit affect slightly the performance of the job-shop.job shop, order negotiation, workload control

Volume change in contractional kink bands; examples from the NNE-SSW Late Variscan kink bands of Portugal

Kink bands are usually associated to the late deformation stages in polydeformed areas, being developed in rocks that present a strong planar mechanical anisotropy (e.g. layering or cleavage). In Portugal, the Late Variscan deformation episode generates in Almograve and Abrantes regions (SW Iberian Massif), brittle to brittle-ductile NNE-SSW sinistral kink bands, which deflects and deforms the NNW-SSE regional trend related to the earlier tectonic events. These defection induces a counterclockwise rotation of subvertical primary layering/foliation in inner domains of the kink bands. The rotation inevitably distort previous structures, generating a complex structural pattern in response to kink folding mechanism, but with particular features in each case. In Almograve, within metric to decametric sinistral kink bands, a wide spectrum of structures were developed, including distinct fold patterns (among which flexural slip folds) and brittle to brittle-ductile shear zones. In the inner domains of the Abrantes metric kink band, a high strain pattern composed by 2nd order conjugate kink bands, acting as “strain slip cleavage” is found. The developed mesoscopic structures allows to calculate internal and external stress fields, showing a variation from the outer to inner domains of kink band. The stress field pattern also shows a rotation which is also similar to the exhibit rotation of structures within inner domains. This stress field variation should be related with the deformation mechanisms induced by rotation of primary layering. Indeed, the generated internal structures are clearly controlled by layer parallel shortening and layer parallel slip, which were the two main mechanisms responsible by accommodation of volume distortion within kink bands. This deformation was also conditioned by the rheology and heterogeneities of deformed sequence. As mentioned, during the development of kink bands, the strain is localized within kink band due the internal rotation of primary layering and/or simple shear parallel to kink boundaries. There are no evidences of kink band boundary migration, allowing to classify the kink bands as fixed hinge type III kink bands. In order to estimate the internal shortening parallel to layering during the rotation, it is proposed a new theoretical graphical method for type III kink bands, which allows an expedite shortening measurement based on angular parameters of kink bands. The proposal graphic shows that kink bands presents variable shortening ratio ranging between 5 to 25%. Some care should be used with such shortening values, because small variations in kink band angular values could occur, being induced either by slip in kink band boundaries or the layer parallel slip. However, the new method presents itself as an excellent approach method, as proved by the similar shortening calculated for real structures. The correct geometric analysis also allows to determine that shortening component is dissipated in the other two orthogonal directions, i.e. perpendicular do layering and in vertical direction

Domino structures as a local accommodation process in heterogeneous shear zones

Usually, deformation in rocks is heterogeneously distributed, concentrating on planar zones located between rigid blocks, named shear zones. The geometry and kinematic criteria analysis becomes essential to understand the shear zones dynamics; the dominoes are one of the structures which can be used as a shear kinematic criteria. However, for the application of these structures as kinematic criteria, it is necessary a careful analysis of the tectonic environment associated with these structures. These structures are developed under ductile-brittle to brittle regimes associated to a non-coaxial deformation and obeying Coulomb criterion for failure (Jaeger & Cook, 1981). Dominoes are characterized by the clear predominance of one shear family, that induces the block rotation during the deformation process. These structures are commonly associated to extensive regimes and in strike-slip environments their development is poorly known. In such non coaxial wrench domains, these structures are frequently interpreted as asymmetric boudins at mesoscale. Current work, in Abrantes region (Central Portugal), emphasizes the presence of two major Variscan deformation phases. The second one (D2) is associated with a NW-SE right-lateral non-coaxial shear component; This deformation increase to West, when approaching the Porto-Tomar-Ferreira do Alentejo shear zone, which leads to consider that this dextral first order shear was responsible by D2. The D2 structures are mostly right-lateral shear zones, developed at all scales, affecting clearly the first deformation phase structures. The D2 structures present a heterogeneous development with simple shear dominated transpression domains, alternating with domains that exposing pure shear dominated transpression. Locally, in simple shear dominated transpression domains, it is possible to see a complex Sfabric, characterized by the presence of several families of planar strucures, which accommodates the internal shear zone stress. This fabric is constrained to decimetric layer with well-defined borders and extensively laminated. It’s possible to separate four families of planar structures given our geometry and kinematics: (1) main shear represents NNW-SSE right-lateral kinematics, parallel to the previous anisotropy (S1). This shear acts like a rigid barrier and the other families don’t cut this shear. (2) Shear family 1 are conjugate NNE-SSW to N-S left-lateral shears. Near the main shear the shear orientation is variable. (3) Shear family 2 are NE-SW to E-W left lateral shears, delimiting centimetric to milimetric blocks. This blocks exhibits rotation. It is possible to show more than one generation of shears. (4) Shear family 3 are NNE−SSW shears, with main shear synthetic kinematics. These family behave as c’-bands and have a punctual development. Associated with this S-tectonite, appears cohesive fault rocks (cataclasite; e.g. Sibson, 1977). Cataclasite is characterized by distributed fracture and grain size reduction throughout shears. Therefore the blocks have rigid rotation in a plastic matrix (cataclasite); this heterogeneous flow accommodates the overlaps and gaps creation due the shear zones activity. The cataclastic flow is located near the main shear and shear family 1, yielding a crush zone. The field data shows that the domino spinning is result from dual acting between main shear and family 1 shear

Accommodation structures during kink bands evolution; quantitative methods applied to Late Variscan deformation of Portugal

Kink bands are common in rocks with a strong planar mechanical anisotropy, being generally developed in polydeformed areas during the late stages of deformation, in brittle to brittle-ductile conditions. In the Late Variscan deformation events in the Iberian Massif, several kink band structures were developed in association to the NNE-SSW sinistral strike-slip faults, which are induced by the Laurentia and Gondwana E-W dextral collision on Carboniferous times. Within two metric-scale kink bands, several 2nd order structures are generated in response to internal shortening during layering rotation. The present paper describes the internal geometry and kinematics of these type III fixed hinges kinks bands, discussing their deformation mechanisms. In order to quantify the internal shortening within kink bands, a new graphical method, using simple angular parameters, is proposed. This graphical approach applied to the studied kink bands allows their internal shortening to be quantified; it ranges between 12 to 18%. The genesis of 2nd order structures within kink bands results from the accommodation of the internal layer distortion during kink bands progressive deformation and is controlled by two main deformation processes: layer parallel shortening and layer parallel slip

Internal warehouse management system in Tabaqueira (Philip Morris International)

Estágio realizado na Tabaqueira (Philip Morris International), e orientado pelo Eng. António Marcelo GonçalvesTese de mestrado integrado. Engenharia Industrial e Gestão. Universidade do Porto. Faculdade de Engenharia. 201

Novas moléculas antivirais, que futuro?

A Virologia é uma área em expansão, através desta conseguiu-se caracterizar os vírus conhecidos atualmente. Estes possuem características comuns entre eles, tais como ácido nucleico ou uma cápside e outras que são característica apenas de alguns, por exemplo, invólucro. Os vírus são ainda parasitas intracelulares obrigatórios e necessitam da maquinaria do hospedeiro para se replicarem e provocar uma infeção. No âmbito das inúmeras doenças provocadas por vírus a ciência tem-se dedicado á investigação de formas de combater estes parasitas capazes de provocar grandes danos nas populações. Das moléculas abordadas, algumas já existiam e apenas se descobriu a sua ação antiviral ate então desconhecida, por outro lado novas moléculas têm sido exploradas com resultados terapêuticos animadores, contudo é ainda necessário mais tempo e mais investigação. A procura de novas formas/moléculas para combater os vírus exige tempo, dedicação e tem custos elevados, para isso são necessários meios, paciência e apoios. Apesar de tudo têm surgido resultados prometedores nesta área de investigação o que representa esperança num futuro melhor.The Virology is a growing area, through this we were able to characterize the currently known viroses. These have common characteristics between them, such as nucleic acid or capsid and others that are characteristic of only some, for example, housing. Viroses are obligate intracellular parasites and still require the machinery of the host to replicate and cause an infection. Within the numerous diseases caused by viruses science has been dedicated to research ways to combat these parasites capable of causing extensive damage in populations. Addressed some of the molecules existed and only discovered its antiviral action until then unknown, on the other hand new molecules have been explored with promising therapeutic results, yet it is still needed more time and research. The search for new forms/molecules to combat the virus requires time, dedication and has high cost, to that it is necessary means, patience and support. After all there have been promising results in this area of research which represents hope for a better future

How do I design a location-dependent application?

The generalisation of the Internet and the recent technological developments in embedded systems and wireless networks contribute to the realisation of a vision where access to information is possible at any moment and from anywhere. This is particularly attractive with information that is relevant to a specific geographic location. Applications that rely on location-based services to provide information to mobile users, or that support interaction with real devices in the user neighbourhood, are called location-dependent applications and enhance the relationship between mobile users and a specific geographic location. However, the design of such applications breaks with the existing paradigms and methodologies as the mobile devices and the wireless communication infrastructures have characteristics that are very different from those of desktop computers and wired communication systems. The Around architecture is an open and extensible framework for location-based services that allows network services to be associated with specific geographic locations. By using this architecture applications can select services that are relevant for specific locations. Within the context of the Around project we have developed a prototype system with multiple location-based services and an application that accesses these services to provide information related to a town transportation system. This paper reports on the design and development of this location-based application. Its design raised several new issues, going from the computational model to the interface paradigm, which are also discussed in this paper. The developed application is composed of several modules: a set of agents which are autonomous units with the knowledge necessary to select and use location-based services in a specific thematic area (e.g. transportation); an HTML output area based on a browser metaphor; and a location-context module responsible for determining the user context. The results show that an application architecture based on a modular approach turns to be very flexible as it becomes very easy to extend its functionality by simply adding or changing the agents that deal with each location-based service.Fundação para a Ciência e a Tecnologia (FCT) - (PRAXIS/P/EEI/14267/1998)