731 research outputs found

    Sampling sufficiency for mechanical properties of wood

    Get PDF
    Based on most recently published studies, there is a large variability in both the mechanical properties of wood and sample sizes selected to evaluate them. This study aims to define sampling sufficiency for some mechanical properties of wood, which were bending strength, bending modulus, compressive strength, compressive modulus, hardness, and shear strength. The mechanical tests were carried out according to the ASTM D143 on wood samples cut from clonal Eucalyptus planted in southern Brazil. Sampling sufficiency was determined by an intensive computational method based on resampling of original data using Monte Carlo simulations. The experimental tests data conformed to the normal distribution and most of the obtained sufficient sample sizes determined by Monte Carlo simulation were above those sample sizes used in most already published studies. Furthermore, properties related to wood stiffness presented smaller variabilities than their respective properties associated with wood strength, leading to smaller sample sizes for the former cases

    Depinning of three-dimensional drops from wettability defects

    Full text link
    Substrate defects crucially influence the onset of sliding drop motion under lateral driving. A finite force is necessary to overcome the pinning influence even of microscale heterogeneities. The depinning dynamics of three-dimensional drops is studied for hydrophilic and hydrophobic wettability defects using a long-wave evolution equation for the film thickness profile. It is found that the nature of the depinning transition explains the experimentally observed stick-slip motion.Comment: 6 pages, 9 figures, submitted to ep

    Beyond technology: pottery reveals translocal social relations at a Bell Beaker Monumental Site in Central Europe

    Get PDF
    The Bell Beaker site near Brodek u Prostějova (Czechia) has yielded remains of a large timber construction accompanied by four symmetrical ritual deposits with numerous artefacts, including more than fifty ceramic vessels. Their decoration consists of incised patterns, in nineteen cases with preserved white inlaid incrustations. To investigate the social relations at this extraordinary site, a multi-analytical and micro-destructive approach was employed to determine the provenance and technology of the pottery and the composition of the white incrustations. The results indicate various origins for the pottery within the region and the presence of extra-regional fabrics and graphitic temper. The main raw materials for the white inlays were calcium carbonate (calcite), hydroxyapatite (bone), and bright clay. The mixing of decorative motifs and the variation in the shape and size of the beakers suggest unique manufacturing processes. These results lend support to the monumental site of Brodek serving as a ritual place for several communities from both local and wider areas.Introduction Materials and methods Results - Ceramic petrography and chemical composition White inlay incrustations - Micro Fourier transform infrared spectroscopy (μFTIR) - Micro X-ray diffraction (μXRD) - Scanning electron microscopy-electron dispersive spectroscopy (SEM-EDS) Metrics abd decoration analysis Discussion - Ceramic provenance and materials of white incrustations - Depositional semantics and ceramic patterns in the ritual features - Translocal social relationships and the circulation of ceramics and other artefacts Conclusio

    Wood Flour Modified by Poly(furfuryl alcohol) as a Filler in Rigid Polyurethane Foams: Effect on Water Uptake

    Get PDF
    The use of lignocellulosic fillers in rigid polyurethane foams (RPUFs) has been receiving great attention due to their good mechanical and insulation properties and the high sustainable appeal of the obtained cellular polymers, although high water uptakes are found in most of these systems. To mitigate this detrimental effect, RPUFs filled with wood flour (2.5% wt) were fabricated with the addition of furfuryl alcohol (FA) to create a polymer grafted with the wood filler. Two concentrations of FA (10 wt% and 15 wt%) were investigated in relation to the wood flour, and the RPUFs were characterized for cell morphology, density, compressive properties, thermal stability, and water uptake. The introduction of wood flour as a filler decreased the cell size and increased the anisotropy index of the RPUFs and, in addition to that, the FA grafting increased these effects even more. In general, there were no significant changes in both mechanical and thermal properties ascribed to the incorporation of the fillers. On the other hand, a reduction of up to 200% in water uptake was ascribed to the FA-treated fillers.This work was supported by the Coordination for the Improvement of Higher Education—CAPES (code 001), the National Council for Scientific and Technological Development—CNPq (Financial code 301758/2019-0) and the University of Basque Country (COLAB20/04)

    An evidence based clinical aid for cardiovascular disease

    Get PDF
    Copyright to Australian Family Physician. Reproduced with permission. Permission to reproduce must be sought from the publisher, The Royal Australian College of General Practitioners.Cardiovascular disease is the commonest cause of mortality in Australia, accounting for more than 30% of deaths. Hypertension, diabetes and lipid disorders account for 15.6% of the total problems encountered in general practice. Therefore all doctors should be familiar with well known risk factors for cardiovascular disease, as well as the benefits of interventions with them.Brian R McAvoy; Greg R Fulcher; John V Amerena; Greg W Conner; John F Beltrame; Graeme J Hankey; Anthony C Keech; Brian L Lloyd; Michael L Neale; Carol A Pollock; Krishna Sudhir; Robert D Waltham; Malcolm J Wes

    Interpreting ambiguous ‘trace’ results in Schistosoma mansoni CCA Tests: Estimating sensitivity and specificity of ambiguous results with no gold standard

    Get PDF
    Background The development of new diagnostics is an important tool in the fight against disease. Latent Class Analysis (LCA) is used to estimate the sensitivity and specificity of tests in the absence of a gold standard. The main field diagnostic for Schistosoma mansoni infection, Kato-Katz (KK), is not very sensitive at low infection intensities. A point-of-care circulating cathodic antigen (CCA) test has been shown to be more sensitive than KK. However, CCA can return an ambiguous ‘trace’ result between ‘positive’ and ‘negative’, and much debate has focused on interpretation of traces results. Methodology/Principle findings We show how LCA can be extended to include ambiguous trace results and analyse S. mansoni studies from both Côte d’Ivoire (CdI) and Uganda. We compare the diagnostic performance of KK and CCA and the observed results by each test to the estimated infection prevalence in the population. Prevalence by KK was higher in CdI (13.4%) than in Uganda (6.1%), but prevalence by CCA was similar between countries, both when trace was assumed to be negative (CCAtn: 11.7% in CdI and 9.7% in Uganda) and positive (CCAtp: 20.1% in CdI and 22.5% in Uganda). The estimated sensitivity of CCA was more consistent between countries than the estimated sensitivity of KK, and estimated infection prevalence did not significantly differ between CdI (20.5%) and Uganda (19.1%). The prevalence by CCA with trace as positive did not differ significantly from estimates of infection prevalence in either country, whereas both KK and CCA with trace as negative significantly underestimated infection prevalence in both countries. Conclusions Incorporation of ambiguous results into an LCA enables the effect of different treatment thresholds to be directly assessed and is applicable in many fields. Our results showed that CCA with trace as positive most accurately estimated infection prevalence

    Tratamentos biológico e químico em sementes de Cedrela fissilis para controle de Rhizoctonia sp.

    Get PDF
    Neste trabalho, objetivou-se avaliar o efeito de um fungicida protetor e de um produto biológico, utilizados isoladamente e combinados, no controle de patógenos presentes em sementes de cedro (Cedrela fissilis), especialmente de Rhizoctonia sp. Anteriormente ao tratamento das sementes, parte das sementes foi previamente inoculada com Rhizoctonia sp., isolado de sementes de cedro, e parte recebeu os tratamentos sem a inoculação. Após, as sementes foram submetidas a tratamentos com produto biológico em pó à base de Trichoderma spp. (aplicado isoladamente), fungicida Captan em pó (também aplicado isoladamente), combinação dos dois produtos aplicados em uma dose considerada máxima (100%) e combinação de metade da dose de ambos os produtos (50%) e ainda a testemunha. As avaliações constaram dos testes de germinação, sanidade em papel-filtro, emergência e das avaliações de mudas. Nenhum tratamento conseguiu erradicar Rhizoctonia sp. das sementes inoculadas, porém o tratamento com 100% da dose de ambos os produtos reduziu sua incidência. A combinação de produto químico e biológico, apresenta-se como uma alternativa viável para o tratamento de sementes de cedro, especialmente no controle de Rhizoctonia sp

    A global fit to determine the pseudoscalar mixing angle and the gluonium content of the eta' meson

    Full text link
    We update the values of the eta-eta' mixing angle and of the eta' gluonium content by fitting our measurement R_phi = BR(phi to eta' gamma)/ BR(phi to eta gamma) together with several vector meson radiative decays to pseudoscalars (V to P gamma), pseudoscalar mesons radiative decays to vectors (P to V gamma) and the eta' to gamma gamma, pi^0 to gamma gamma widths. From the fit we extract a gluonium fraction of Z^2_G = 0.12 +- 0.04, the pseudoscalar mixing angle psi_P = (40.4 +- 0.6) degree and the phi-omega mixing angle psi_V = (3.32 +- 0.09) degree. Z^2_G and psi_P are fairly consistent with those previously published. We also evaluate the impact on the eta' gluonium content determination of future experimental improvements of the eta' branching ratios and decay width.Comment: 13 pages, 7 figures to submit to JHE

    Study of the a_0(980) meson via the radiative decay phi->eta pi^0 gamma with the KLOE detector

    Full text link
    We have studied the phi->a_0(980) gamma process with the KLOE detector at the Frascati phi-factory DAPhNE by detecting the phi->eta pi^0 gamma decays in the final states with eta->gamma gamma and eta->pi^+ pi^- pi^0. We have measured the branching ratios for both final states: Br(phi->eta pi^0 gamma)=(7.01 +/- 0.10 +/- 0.20)x10^-5 and (7.12 +/- 0.13 +/- 0.22)x10^-5 respectively. We have also extracted the a_0(980) mass and its couplings to eta pi^0, K^+ K^-, and to the phi meson from the fit of the eta pi^0 invariant mass distributions using different phenomenological models.Comment: 17 pages, 6 figures, submitted to Physics Letters B. Corrected typos in eq.
    corecore