625 research outputs found

    Improving the dynamical behaviour of a laser cutting equipment by using a carbon fibre composite main structural runway frame

    Get PDF
    In order to improve the dynamic behaviour of an industrial laser cutting equipment a sandwich solution, using a carbon fibre reinforced polymer (CFRP) and polyester foam core, was implemented to construct its main runway structural frame, which supports the cutting head and major laser beam mirrors and lens. Nowadays, the commercial competiveness of laser cutting equipments is considerable enhanced by their higher cutting speed and precision, as well as, cost. With the recent available higher power laser beam generators and swifter motors quicker and powerful cuts may be already done. However, at accelerations of 3 and 4 g’s already enabled by linear motors, the lack of stiffness and high mass and consequent inertia of the traditional runway structural frames, made from steel and/or aluminium, do not allow achieving high required cutting precisions. Thus, the present study considered replacing those conventional materials by much lighter advanced CRFP composites to improve the dynamic performance of an existing laser cutting equipment. Advanced numeric Finite Element Method (FEM) calculations by using the ANSYS package software were made to verify the static and dynamic behaviours of the new composite structural frame and compare them to simulations made with the currently used steel solution. The composite structural frame processing method has been also studied and defined in this work. Furthermore, the composite laminate has been optimised by defining the better number of stacking layers and fibre orientations to be used, as well as, the foam core thickness. The failure of the new sandwich structural composite runway frame has been verified through the Tsai-Wu criterion. Finally, an economic analysis of the viability of the new composite solution adopted will be also presented.Adira, S

    Improving the dynamical behaviour of a laser cutting equipment by using a carbon fibre composite main structural runway frame

    Get PDF
    In order to improve the dynamic behaviour of an industrial laser cutting equipment a sandwich solution, using a carbon fibre reinforced polymer (CFRP) and polyester foam core, was implemented to construct its main runway structural frame, which supports the cutting head and major laser beam mirrors and lens. Nowadays, the commercial competiveness of laser cutting equipments is considerable enhanced by their higher cutting speed and precision, as well as, cost. With the recent available higher power laser beam generators and swifter motors quicker and powerful cuts may be already done. However, at accelerations of 3 and 4 g’s already enabled by linear motors, the lack of stiffness and high mass and consequent inertia of the traditional runway structural frames, made from steel and/or aluminium, do not allow achieving high required cutting precisions. Thus, the present study considered replacing those conventional materials by much lighter advanced CRFP composites to improve the dynamic performance of an existing laser cutting equipment. Advanced numeric Finite Element Method (FEM) calculations by using the ANSYS package software were made to verify the static and dynamic behaviours of the new composite structural frame and compare them to simulations made with the currently used steel solution.The composite structural frame processing method has been also studied and defined in this work. Furthermore, the composite laminate has been optimised by defining the better number of stacking layers and fibre orientations to be used, as well as, the foam core thickness. The failure of the new sandwich structural composite runway frame has been verified through the Tsai-Wu criterion. Finally, an economic analysis of the viability of the new composite solution adopted will be also presented

    A bending cell for small batches

    Get PDF
    This article presents the study that is done for the conception of an automated bending cell devoted to the processing of parts in small batches, gathering the real necessities of potential customers. Joining the maximum of possible information, on the present cells, is has been able to conceive an automated bending cell devoted to the bending of parts, with dif-ferent form, weight, thickness, etc., in small batches. To be able to reach the proposed objec-tives, the cell is equipped with auxiliary systems, such as ATC (Automatic Tool Change) allied to a tool warehouse, AGC (Automatic Gripper Change) with three different grippers, a repo-sition station, and a dedicated 7th axis in the press brake designed to dock a standard 6 axes robot, that provide to cell a sufficient grade of autonomy. Allied with the idea of creating a cell for small batches, is introduced the target of getting this cell at lower price as possible. Thus the cell acquires an extended application range very important for potential customers. To get real perception of the money saving when working with this automated bending cell comparisons between Man work times vs. machine work times in production of small batches have been made

    Estimativa da massa e volume de frutos de café usando métodos não destrutivos.

    Get PDF
    A avaliação do crescimento dos frutos do café é, normalmente, feita por coleta do fruto, inviabilizando a avaliação continua do mesmo fruto durante toda sua maturação. O objetivo deste trabalho foi estabelecer métodos não destrutivos, baseados em modelos de regressão, para estimar massas seca e fresca e volume de frutos de café a partir de medidas dos comprimentos longitudinal e transversal do fruto. O estudo foi conduzido em cafezal da cultivar IAPAR 59, sem irrigação, instalado na Estação Experimental do IAPAR em Londrina, PR. Foram tomadas as medidas de maior diâmetro longitudinal (comprimento), maior e menor diâmetro transversal (largura), volume, massa fresca e massa seca de frutos em diferentes estádios de desenvolvimento, e analisadas as correlações entre elas. Concluiu-se que as massas fresca e seca e o volume dos frutos podem ser estimados de forma eficiente e não destrutiva a partir de medidas de comprimento e largura

    Principles of condom provision programs in prisons from the standpoint of European prison health experts: a qualitative study

    Get PDF
    Background Condom provision is one of the most effective harm reduction interventions to control sexually transmitted infections (STIs) including HIV/AIDS and viral hepatitis in prisons. Yet, very few countries around the world provide prisoners with condoms. The present study aimed to elucidate principles of effective prison-based condom programs from the perspective of European public health and prison health experts. Methods As a part of the “Joint Action on HIV and Co-infection Prevention and Harm Reduction (HA-REACT)” twenty-one experts from the field of prison health from eight European countries were invited to discuss the principles of condom provision programs in prisons within two focus groups. The audio records were transcribed verbatim, coded, categorized, and analyzed using thematic analysis method. Results Six components emerged from the analysis as essential for successful condom programs in prisons: (1) highlighting the necessity of condom provision in prisons, (2) engagement of internal and external beneficiaries in all stages of designing and implementing the program, (3) conducting a pilot phase, (4) condom program in a comprehensive package of harm reduction interventions, (5) vending machine as the best method of condom distribution in prisons and (6) assuring the sustainability and quality of the intervention. Conclusion Results of the present study can help prison health policy makers to design and conduct acceptable, accessible and high-quality prison-based condom provision programs, and consequently to mitigate the burden of STIs in prisons. Having access to high-quality healthcare services including condom provision programs is not only the right of prisoners to health, but also is a move towards achieving the sustainable development goal 3 of “leaving no one behind.”Open Access funding enabled and organized by Projekt DEAL

    cis-Regulatory Requirements for Tissue-Specific Programs of the Circadian Clock

    Get PDF
    SummaryBackgroundBroadly expressed transcriptions factors (TFs) control tissue-specific programs of gene expression through interactions with local TF networks. A prime example is the circadian clock: although the conserved TFs CLOCK (CLK) and CYCLE (CYC) control a transcriptional circuit throughout animal bodies, rhythms in behavior and physiology are generated tissue specifically. Yet, how CLK and CYC determine tissue-specific clock programs has remained unclear.ResultsHere, we use a functional genomics approach to determine the cis-regulatory requirements for clock specificity. We first determine CLK and CYC genome-wide binding targets in heads and bodies by ChIP-seq and show that they have distinct DNA targets in the two tissue contexts. Computational dissection of CLK/CYC context-specific binding sites reveals sequence motifs for putative partner factors, which are predictive for individual binding sites. Among them, we show that the opa and GATA motifs, differentially enriched in head and body binding sites respectively, can be bound by OPA and SERPENT (SRP). They act synergistically with CLK/CYC in the Drosophila feedback loop, suggesting that they help to determine their direct targets and therefore orchestrate tissue-specific clock outputs. In addition, using in vivo transgenic assays, we validate that GATA motifs are required for proper tissue-specific gene expression in the adult fat body, midgut, and Malpighian tubules, revealing a cis-regulatory signature for enhancers of the peripheral circadian clock.ConclusionsOur results reveal how universal clock circuits can regulate tissue-specific rhythms and, more generally, provide insights into the mechanism by which universal TFs can be modulated to drive tissue-specific programs of gene expression

    Substituting conventional steel alloys by carbon fibre composites in structural parts of an existing laser cutting equipment

    Get PDF
    In the present work, a finite element (FE) analysis was employed to validate the use of advanced carbon fibre composites as replacement of traditional low-alloy steel in the construction of the main runway frame structure of a laser cutting equipment currently available in the market. This new composite solution was adopted to increase the current laser equipment precision and cutting speed. The main objective was to enhance the machine cutting performance by using much stiffer and lighter main structural runway frames to support the machine cutting head and all major laser beam mirrors and lens, which allows decreasing dramatically the inertial and vibration efforts developed in service through the use of carbon fibre composites. The paper presents, compares and discusses the mechanical and dynamical behaviour obtained in the FE simulations made by using both solutions, the current one based on a steel frame and the new innovative composite adopted structure. The processing method to be used in the production of the innovative composite structure is also proposed. Finally, as production costs may also have an important impact on final equipment commercial price and acceptation, an economical study considering both manufacturing situations (currently used and new one) are discussed

    Portuguese validation of the Cambridge pulmonary hypertension outcome review (CAMPHOR) questionnaire

    Get PDF
    BACKGROUND: Patients with pulmonary arterial hypertension (PAH) and other forms of precapillary pulmonary hypertension (PH) have impaired quality of life (QoL). The Cambridge Pulmonary Hypertension Outcome Review (CAMPHOR) is a PH-specific patient-reported outcome measure that assesses symptoms, activity limitations and QoL. It was originally developed in UK-English. The main objective of this study was to create an adaptation of the CAMPHOR suitable for a Portuguese-speaking population. METHODS: A multi-step approach was followed: bilingual and lay panel translation; cognitive debriefing interviews; and psychometric testing in repeated postal surveys (2 weeks apart) including assessment of internal consistency, reproducibility and validity. The Nottingham Health Profile (NHP) questionnaire was used as a comparator instrument to test convergent validity. RESULTS: The CAMPHOR was translated without difficulty by the two panels. Cognitive debriefing interviews showed the questionnaire was easily understood and considered relevant to patients' experience with their illness. Psychometric evaluation was performed with 50 PAH patients (47 ± 14 years, 37 women). Cronbach's alpha coefficients showed good internal consistency for the three CAMPHOR scales [Symptoms = 0.95; Activities = 0.93 and QoL = 0.94]. Test-retest coefficients showed that all scales had excellent reliability (Symptoms = 0.94; Activities = 0.89 and QoL = 0.93), indicating low levels of random measurement error. The CAMPHOR correlated as expected with the NHP. The magnitude of correlations followed a similar pattern to those in the original development study. The CAMPHOR also exhibited evidence of known group validity in its ability to distinguish between self-reported severity and general health groups. CONCLUSIONS: A valid and reliable version of the CAMPHOR questionnaire for the European Portuguese-speaking population was developed and is recommended for use.info:eu-repo/semantics/publishedVersio
    corecore