2,517 research outputs found

    A brief study of some aspects of early father-child relationship

    Full text link
    Thesis (M.S.)--Boston Universit

    Markov Chain Monitoring

    Full text link
    In networking applications, one often wishes to obtain estimates about the number of objects at different parts of the network (e.g., the number of cars at an intersection of a road network or the number of packets expected to reach a node in a computer network) by monitoring the traffic in a small number of network nodes or edges. We formalize this task by defining the 'Markov Chain Monitoring' problem. Given an initial distribution of items over the nodes of a Markov chain, we wish to estimate the distribution of items at subsequent times. We do this by asking a limited number of queries that retrieve, for example, how many items transitioned to a specific node or over a specific edge at a particular time. We consider different types of queries, each defining a different variant of the Markov chain monitoring. For each variant, we design efficient algorithms for choosing the queries that make our estimates as accurate as possible. In our experiments with synthetic and real datasets we demonstrate the efficiency and the efficacy of our algorithms in a variety of settings.Comment: 13 pages, 10 figures, 1 tabl

    An integrated approach project for the revaluation of a traditional sourdough bread production chain

    Get PDF
    The influence of organic and conventional farming systems on the performance of a panel of old and modern Italian bread wheat varieties has been evaluated, with the aim to individuate an agronomic protocol suitable for the production of a sourdough bread traditionally prepared in a hill zone of Emilia-Romagna. The agronomic and technological characterisation of the wheat samples obtained in organic and conventional farming conditions has been done and the sensorial qualities of the sourdough bread obtained have been evaluated

    Residual stress of as-deposited and rolled Wire + Arc Additive Manufacturing Ti–6Al–4V components

    Get PDF
    Wire + arc additive manufacturing components contain significant residual stresses, which manifest in distortion. High-pressure rolling was applied to each layer of a linear Ti–6Al–4V wire + arc additive manufacturing component in between deposition passes. In rolled specimens, out-of-plane distortion was more than halved; a change in the deposits' geometry due to plastic deformation was observed and process repeatability was increased. The Contour method of residual stresses measurements showed that although the specimens still exhibited tensile stresses (up to 500 MPa), their magnitude was reduced by 60%, particularly at the interface between deposit and substrate. The results were validated with neutron diffraction measurements, which were in good agreement away from the baseplate

    Polaron Effects on Superexchange Interaction: Isotope Shifts of TNT_N, TCT_C, and TT^* in Layered Copper Oxides

    Full text link
    A compact expression has been obtained for the superexchange coupling of magnetic ions via intermediate anions with regard to polaron effects at both magnetic ions and intermediate anions. This expression is used to analyze the main features of the behavior of isotope shifts for temperatures of three types in layered cuprates: the Neel temperatures (TNT_N), critical temperatures of transitions to a superconducting state (TCT_C), and characteristic temperatures of the pseudogap in the normal state (TT^*).Comment: 4 pages, 1 figur

    Nucleation and Growth Dynamics of the α-Al / β-Al5FeSi Eutectic in a Complex Al-Si-Cu-Fe Alloy

    Get PDF
    Secondary-sourced recycled aluminium alloys can exhibit high levels of different impurities. It is well known that the presence of iron, the most common impurity, can lead to the formation of hard and brittle intermetallic phases which are detrimental to the machining properties and the mechanical behaviour of the material in service. The purpose of this work is to study the nucleation and growth of the β-Al5FeSi intermetallic phase in the framework of the eutectic reaction: Liquid → α-Al + β-Al5FeSi. In situ X-ray microtomography has been used to investigate the formation of the irregular eutectic β-phase plates during the solidification at low cooling rate of an Al-8Si-4Cu-0.8Fe alloy. The results show that only a few plates form, nucleating early near the sample surface. Next, growth occurs very rapidly in the principal growth direction and slowly in the thickness direction. The plates are highly branched and appear to form as a divorced eutectic, i.e. not coupled with the α-Al. These features are inconsistent with the common irregular eutectic solidification theory based on the Jackson and Hunt model

    Selection of cellulolytic fungi isolated from diverse substrates.

    Get PDF
    The aim of the present work was to select filamentous fungi isolated from diverse substrates to obtain the strains with potential to produce the hydrolytic enzymes. From a total of 215 strains, seven strains from the soils, six from the plants and one from sugarcane bagasse were selected and identified as belonging to the Trichoderma, Penicillium and Aspergillus genera. The best hydrolytic activities obtained by semi-solid fermentation using these strains were approximately: 35; 1; 160; 170 and 120 U/gdm (CMCase, FPase, ?-glucosidase, xylanase and polygalacturonase, respectively), demonstrating their potential to synthesize the enzymes compared with the results reported in the literature
    corecore