Evaluation of the changes in working limits in an automobile assembly line using simulation

The aim of the work presented in this paper consists of the development of a decision-making support system, based on discrete-event simulation models, of an automobile assembly line which was implemented within an Arena simulation environment and focused at a very specific class of production lines with a four closed-loop network configuration. This layout system reflects one of the most common configurations of automobile assembly and preassembly lines formed by conveyors. The sum of the number of pallets on the intermediate buffers, remains constant, except for the fourth closed-loop, which depends on the four-door car ratio (x) implemented between the door disassembly and assembly stations of the car body. Some governing equations of the four closed-loops are not compatible with the capacities of several intermediate buffers for certain values of variable x. This incompatibility shows how the assembly line cannot operate in practice for x0,97 in a stationary regime, due to the starvation phenomenon or the failure of supply to the machines on the production line. We have evaluated the impact of the pallet numbers circulating on the first closed-loop on the performance of the production line, translated into the number of cars produced/hour, in order to improve the availability of the entire manufacturing system for any value of x. Until the present date, these facts have not been presented in specialized literature. © 2012 American Institute of Physics

Impact of technological facilitators in the design and artisanal production processes. The Guarda Ninhos Project - craft and design of Gonçalo’s basketry

This research project analyses the impact of the use of prototyping and digital manufacturing tools in the development of new products based on the theme of Gonçalo's basketwork, in Guarda, Portugal [1]. Guarda Ninhos is an inclusive entrepreneurship project, the aim of which was to develop, produce and promote new local handicraft products. Solutions based on the socio-cultural, ecological and economic heritage of this region, knowledge immaterial heritage and expertise of their communities. Reinventing the culture of this place as a way of creating social and economic value, with the people who live there, was the followed line of action. Based on the results obtained, an attempt was made to outline forms of cooperation between this type of artisanal activities, with the most recent concepts of "industry 4.0" and industrial development methodologies - namely, (A) verifying the beneficial impact that the use of prototyping and digital fabrication tools can play in the design process of these products, optimising the development and production processes without jeopardising the premises that define the artisanal product; (B) contributing to the registration of ancestral knowledge and consolidation of artisanal processes and (C) showing how a strategic plan that aims to bring together and sustain the interdisciplinary artisan-designer relationship can be implemented.info:eu-repo/semantics/publishedVersio

Super-roughening as a disorder-dominated flat phase

We study the phenomenon of super-roughening found on surfaces growing on disordered substrates. We consider a one-dimensional version of the problem for which the pure, ordered model exhibits a roughening phase transition. Extensive numerical simulations combined with analytical approximations indicate that super-roughening is a regime of asymptotically flat surfaces with non-trivial, rough short-scale features arising from the competition between surface tension and disorder. Based on this evidence and on previous simulations of the two-dimensional Random sine-Gordon model [Sanchez et al., Phys. Rev. E 62, 3219 (2000)], we argue that this scenario is general and explains equally well the hitherto poorly understood two-dimensional case.Comment: 7 pages, 4 figures. Accepted for publication in Europhysics Letter

Visualizing the 3D Polar Power Patterns and Excitations of Planar Arrays with Matlab

[Abstrac] This paper discusses the use of Matlab to create three-dimensional polar plots of the power patterns of planar arrays together with 3D plots of the amplitudes and phases of their excitations. A few lines of Matlab M-code suffice to create complex plots

Effects of Measurement Distance on Measurements of Symmetrically Shaped Patterns Generated by Line Sources

[Abstract] Symmetrically shaped patterns, generated by real continuous linear apertures derived from Taylor distributions, resemble Taylor sum patterns in regard to the distance-dependence of their sidelobe heights. Their ripple shows negligible near-field degradation. If the aperture distribution is complex, however, the ripple and sidelobe levels show previously unreported degradation behavior, including a lowering of the first sidelobe level

Variation in The Bandwidths of Pattern-Quality Parameters and Maximum Embedded Impedance among the Solutions to Shaped-Beam Synthesis Problems for Collinear Dipole Arrays

[Abstract] We investigated variation in the bandwidths of ripple, sidelobe level, -3 dB beamwidth, and maximum element embedded (active) impedance (|Z/sup e/|/sub max/) among multiple collinear dipole arrays radiating a given flat-topped beam pattern. The main finding was that ripple and sidelobe level bandwidths are much greater than when the dipoles are parallel

Replication of Micro Laser Textures by Injection Molding

AbstractIncreasingly micro technology becomes more important in order to develop new products with high added value. These new technologies known as micro allow us manufacturing precision components; these new micro components should work and take carrying out the functions previously performed by larger parts. Microinjection is one of these new technologies. This has the capacity to produce parts, for different materials both plastic and metal and for some industries and applications. The main objective in this paper is to determine the replicate microtextures capability for plastic injection molds. For our samples, ABS plastic is injected into four aluminum cavities with different laser textures performed in, using different technologies to get them. In order to analyze how mold texture affects parts, optical interferometry technique was selected to measure it. The superficial topography obtained was processed using MountainsMapTM software, in order to get the replicability of injected parts. It has also been used an electron microscopy (SEM) to evaluate the mold textures and injected parts in a photographically way

Cardiorespiratory and Metabolic Responses to Low-Intensity Blood-Flow Restricted Running

Low-intensity (LI) aerobic exercise with blood-flow restriction (BFR) increases heart rate (HR), oxygen consumption (VO2), and ratings of perceived exertion (RPE), sometimes to similar levels as high-intensity (HI) exercise. Distance runners may benefit from LI-BFR running in periods of reduced volume or intensity, possibly due to injury. PURPOSE: To compare HR, VO2, blood lactate (BLa), and RPE during LI-BFR running and HI running without BFR. METHODS: Fifteen female distance runners (age 23+4yrs, height 1.67+0.50m, body mass 57.6+5.7kg, VO2max 51.0+4.5mL•kg-1•min-1) completed three randomized 12-minute running conditions: LI control (40% VO2max), HI (80% VO2max), and LI-BFR (40% VO2max). VO2, HR, and RPE were measured at rest, and every 3-minutes. BLa was measured at rest, immediately-post (ImmPost), and 3-minutes post-exercise (3minPost). RESULTS: VO2 remained steady among each condition (p=0.075,ηp2=0.155). The average VO2 differed between the conditions (p\u3c0.001), as HI (39.4+3.9mL•kg-1•min-1) \u3e LI-BFR (25.3+2.6mL•kg-1•min-1) \u3e LI (22.5+3.1mL•kg-1•min-1). HR increased at the onset of exercise and differed between the conditions (p\u3c0.001,ηp2=0.745). The average HR for HI, LI-BFR, and LI were 166+8bpm, 142+13bpm, and 124+11bpm, respectively. BLa was similar in HI and LI-BFR ImmPost and 3minPost (p\u3e0.05), and both were higher than LI (p\u3c0.017). Average RPE in the HI and LI-BFR conditions were similar (p=0.236). CONCLUSION: HI elicits greater VO2 and HR responses than LI-BFR running, suggesting that HI would result in more robust long-term training responses. However, if one cannot engage in HI running because of injury and rehabilitation, LI-BFR running could be a feasible temporary alternative