542 research outputs found

    A fuzzy-QFD approach for the enhancement of work equipment safety: a case study in the agriculture sector

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    The paper proposes a design for safety methodology based on the use of the Quality Function Deployment (QFD) method, focusing on the need to identify and analyse risks related to a working task in an effective manner, i.e. considering the specific work activities related to such a task. To reduce the drawbacks of subjectivity while augmenting the consistency of judgements, the QFD was augmented by both the Delphi method and the fuzzy logic approach. To verify such an approach, it was implemented through a case study in the agricultural sector. While the proposed approach needs to be validated through further studies in different contexts, its positive results in performing hazard analysis and risk assessment in a comprehensive and thorough manner can contribute practically to the scientific knowledge on the application of QFD in design for safety activities

    Hazard function deployment: a QFD-based tool for the assessment of working tasks–a practical study in the construction industry

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    Despite the efforts made, the number of accidents has not significantly decreased in the construction industry. The main reasons can be found in the peculiarities of working activities in this sector, where hazard analysis and safety management are more difficult than in other industries. To deal with these problems, a comprehensive approach for hazard analysis is needed, focusing on the activities in which a working task is articulated since they are characterized by different types of hazards and thus risk levels. The study proposes a methodology that integrates quality function deployment (QFD) and analytic network process methods to correlate working activities, hazardous events and possible consequences. This provides more effective decision-making, while reducing the ambiguity of the qualitative assessment criteria. The results achieved can augment knowledge on the usability of QFD in safety research, providing a basis for its application for further studies

    The Impact of Human Error in the Use of Agricultural Tractors: A Case Study Research in Vineyard Cultivation in Italy

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    Recently, standards and regulations concerning occupational safety have become more and more rigorous. Nevertheless, the number of accidents and victims has not decreased significantly, as reported by official statistics. In Italy, the agricultural sector is certainly one of the most affected by this situation, especially taking into account the occurrence of serious injuries and fatalities related to the use of tractors. The main reasons for such a situation can be ascribed to the peculiarities of agricultural operations. Therefore, when analyzing the root causes of agricultural accidents, a user-centered approach is needed in order to make the development of health and safety interventions easier and more effective. Based on this, the present paper proposes a practical case study research focused on integrating the factor of human error into the risk assessment procedures of agricultural activities in vineyard cultivation. Such an approach allowed us to consider the impact of human errorwhile performing work activities (e.g., the use of a tractor)on hazards and related hazardous events in a thorough manner. The proposed approach represents a novelty in the sector of the safety assessment of agricultural activities, providing a first valuable basis for further analysis and implementation by researchers and practitioners

    The Functional-Engineered Product-Service System (FEPSS) model

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    Throughout recent years, environmental perils have increased and awareness regarding such dangers has improved proportionally. In light of the growing concerns, and coupled with fiercer competition and legislation, product based solutions to meet present and future needs have been deemed insufficient to ensure the planet’s survival. Thus, the birth of integrated product-service offerings, where the product is associated to add-on services, enhancing its performance and achieving higher levels of value for the customer, as well as the manufacturer, with embedded ecological advantages. The service-oriented perspective of delivering solutions is known as Product-Service Systems (PSSs). However, despite advances in acknowledging the benefits that lie in adopting a PSS to answer consumer needs, a formal approach to developing PSS solutions is absent. This dissertation investigates the integration of product design and service design strategies into product-service offerings: overall processes for this integration are present, but the intricate steps of each phase are missing. A literature review examines the most dominant design approaches, as well as design frameworks to structure the PSS design process. The outcome of the review led to the absence of a generic design framework as existing design approaches and processes seemed adapted to a specific context and field. From the examination of the respective literature, we present a four-stage design process, entitled the Functional-Engineered Product-Service System (FEPSS) model, built on a design science approach. Ideation and task analysis, conceptual design, embodiment design, and validation and release are thoroughly detailed with the appropriate tools to define the elements of a PSS. The research then concentrates on the first two stages as they represent the core of PSS design and development process. Ideation and task analysis highlight the use of qualitative tools to define customer requirements, as well as quantitative ones, such as the Kano model, Quality Function Deployment (QFD), the fuzzy logic, and the Analytic Hierarchy Process (AHP) to prioritize these requirements and define the value-creating ones as the basis of the PSS design. Conceptual design presents two approaches to define PSS concepts. The first consists of a functional decomposition approach based on adapting morphological matrices (MMs) to a product-service extending traditional MMs to include the service elements and selection of stakeholders in a product-service integrated setting. The choice of the concept is determined according to a life cycle modelling that illustrates the environmental impact of the proposed concept(s) and compares it/them to the existing offering. The second opts for the QFD for PSS tool augmented by fuzzy logic and the AHP to determine the product and service components of the PSS. Then, the use of Axiomatic Design (AD) shows how a functional decomposition and QFD for PSS can be used to develop PSS modules. Four case studies conducted in the agricultural and biomedical field illustrate the use of the FEPSS and, in particular, its first two phases. The results achieved show the potential of such an approach when implementing a PSS approach, especially in the case of a manufacturer that wants to shift from producing products to providing integrated product-service offerings. At the same time, from a more general perspective, the research work highlighted the benefits of PSSs as they allow the achievement of more sustainable solutions without decreasing the customer values

    Incidence of primary hepatitis C infection and risk factors for transmission in an Australian prisoner cohort

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    Background. Hepatitis C virus (HCV) infection is common in prisoner populations, particularly those with a history of injecting drug use (IDU). Previous studies of HCV incidence have been based on small case numbers and have not distinguished risk event

    Modeling the Subsurface Structure of Sunspots

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    While sunspots are easily observed at the solar surface, determining their subsurface structure is not trivial. There are two main hypotheses for the subsurface structure of sunspots: the monolithic model and the cluster model. Local helioseismology is the only means by which we can investigate subphotospheric structure. However, as current linear inversion techniques do not yet allow helioseismology to probe the internal structure with sufficient confidence to distinguish between the monolith and cluster models, the development of physically realistic sunspot models are a priority for helioseismologists. This is because they are not only important indicators of the variety of physical effects that may influence helioseismic inferences in active regions, but they also enable detailed assessments of the validity of helioseismic interpretations through numerical forward modeling. In this paper, we provide a critical review of the existing sunspot models and an overview of numerical methods employed to model wave propagation through model sunspots. We then carry out an helioseismic analysis of the sunspot in Active Region 9787 and address the serious inconsistencies uncovered by \citeauthor{gizonetal2009}~(\citeyear{gizonetal2009,gizonetal2009a}). We find that this sunspot is most probably associated with a shallow, positive wave-speed perturbation (unlike the traditional two-layer model) and that travel-time measurements are consistent with a horizontal outflow in the surrounding moat.Comment: 73 pages, 19 figures, accepted by Solar Physic

    Evidence for the exclusive decay Bc+- to J/psi pi+- and measurement of the mass of the Bc meson

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    We report first evidence for a fully reconstructed decay mode of the B_c^{\pm} meson in the channel B_c^{\pm} \to J/psi \pi^{\pm}, with J/psi \to mu^+mu^-. The analysis is based on an integrated luminosity of 360 pb$^{-1} in p\bar{p} collisions at 1.96 TeV center of mass energy collected by the Collider Detector at Fermilab. We observe 14.6 \pm 4.6 signal events with a background of 7.1 \pm 0.9 events, and a fit to the J/psi pi^{\pm} mass spectrum yields a B_c^{\pm} mass of 6285.7 \pm 5.3(stat) \pm 1.2(syst) MeV/c^2. The probability of a peak of this magnitude occurring by random fluctuation in the search region is estimated as 0.012%.Comment: 7 pages, 3 figures. Version 3, accepted by PR

    Jet energy measurement with the ATLAS detector in proton-proton collisions at root s=7 TeV

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    The jet energy scale and its systematic uncertainty are determined for jets measured with the ATLAS detector at the LHC in proton-proton collision data at a centre-of-mass energy of √s = 7TeV corresponding to an integrated luminosity of 38 pb-1. Jets are reconstructed with the anti-kt algorithm with distance parameters R=0. 4 or R=0. 6. Jet energy and angle corrections are determined from Monte Carlo simulations to calibrate jets with transverse momenta pT≄20 GeV and pseudorapidities {pipe}η{pipe}<4. 5. The jet energy systematic uncertainty is estimated using the single isolated hadron response measured in situ and in test-beams, exploiting the transverse momentum balance between central and forward jets in events with dijet topologies and studying systematic variations in Monte Carlo simulations. The jet energy uncertainty is less than 2. 5 % in the central calorimeter region ({pipe}η{pipe}<0. 8) for jets with 60≀pT<800 GeV, and is maximally 14 % for pT<30 GeV in the most forward region 3. 2≀{pipe}η{pipe}<4. 5. The jet energy is validated for jet transverse momenta up to 1 TeV to the level of a few percent using several in situ techniques by comparing a well-known reference such as the recoiling photon pT, the sum of the transverse momenta of tracks associated to the jet, or a system of low-pT jets recoiling against a high-pT jet. More sophisticated jet calibration schemes are presented based on calorimeter cell energy density weighting or hadronic properties of jets, aiming for an improved jet energy resolution and a reduced flavour dependence of the jet response. The systematic uncertainty of the jet energy determined from a combination of in situ techniques is consistent with the one derived from single hadron response measurements over a wide kinematic range. The nominal corrections and uncertainties are derived for isolated jets in an inclusive sample of high-pT jets. Special cases such as event topologies with close-by jets, or selections of samples with an enhanced content of jets originating from light quarks, heavy quarks or gluons are also discussed and the corresponding uncertainties are determined. © 2013 CERN for the benefit of the ATLAS collaboration

    Measurement of the inclusive and dijet cross-sections of b-jets in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector

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    The inclusive and dijet production cross-sections have been measured for jets containing b-hadrons (b-jets) in proton-proton collisions at a centre-of-mass energy of sqrt(s) = 7 TeV, using the ATLAS detector at the LHC. The measurements use data corresponding to an integrated luminosity of 34 pb^-1. The b-jets are identified using either a lifetime-based method, where secondary decay vertices of b-hadrons in jets are reconstructed using information from the tracking detectors, or a muon-based method where the presence of a muon is used to identify semileptonic decays of b-hadrons inside jets. The inclusive b-jet cross-section is measured as a function of transverse momentum in the range 20 < pT < 400 GeV and rapidity in the range |y| < 2.1. The bbbar-dijet cross-section is measured as a function of the dijet invariant mass in the range 110 < m_jj < 760 GeV, the azimuthal angle difference between the two jets and the angular variable chi in two dijet mass regions. The results are compared with next-to-leading-order QCD predictions. Good agreement is observed between the measured cross-sections and the predictions obtained using POWHEG + Pythia. MC@NLO + Herwig shows good agreement with the measured bbbar-dijet cross-section. However, it does not reproduce the measured inclusive cross-section well, particularly for central b-jets with large transverse momenta.Comment: 10 pages plus author list (21 pages total), 8 figures, 1 table, final version published in European Physical Journal
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