929 resultados para Direct Strength Method and Experiments


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This paper proposes a model that accounts for “export platform” FDI – a form of FDI that is common in the data but rarely discussed in the theoretical literature. Unlike the previous literature, this paper’s theory nests all the typical modes of supply, including exports, horizontal and vertical FDI, horizontal and vertical export platform FDI. The theory yields the testable hypothesis that a decrease in either inter-regional or intra-regional trade costs induces firms to choose export platform FDI. The empirical analysis provides descriptive statistics which point to large proportions of third country exports of US FDI, and an econometric analysis, whose results are in line with the model’s predictions. The last section suggests policy implications for nations seeking to attract FDI.

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The new Spanish Regulation in Building Acoustic establishes values and limits for the different acoustic magnitudes whose fulfillment can be verify by means field measurements. In this sense, an essential aspect of a field measurement is to give the measured magnitude and the uncertainty associated to such a magnitude. In the calculus of the uncertainty it is very usual to follow the uncertainty propagation method as described in the Guide to the expression of Uncertainty in Measurements (GUM). Other option is the numerical calculus based on the distribution propagation method by means of Monte Carlo simulation. In fact, at this stage, it is possible to find several publications developing this last method by using different software programs. In the present work, we used Excel for the Monte Carlo simulation for the calculus of the uncertainty associated to the different magnitudes derived from the field measurements following ISO 140-4, 140-5 and 140-7. We compare the results with the ones obtained by the uncertainty propagation method. Although both methods give similar values, some small differences have been observed. Some arguments to explain such differences are the asymmetry of the probability distributions associated to the entry magnitudes,the overestimation of the uncertainty following the GUM

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The peak temperature in the corona of plasma ejected by a laser-irradiated slab is discussed in terms of a one-electron-temperature model. Both heat-flux saturation and pulse rise-time effects are considered;the intensity in the rising half of the pulse is approximated by a linear function of time, I(t) = Iot/r. The temperature is found to be proportional to (IQX2)273 and a function of I0X4/r. Above a certain value of I0X4/T, the plasma presents two characteristic temperatures (at saturation and at the critical surface) which can be identified with experimentally observed cold- and hot-electron temperatures. The results are compared with extensive experimental data available for both nd and CO2 lasers, I0(W'cnf2) X2 (/um) starting around 1012. The agreement is good if substantial flux inhibition is assumed (flux-limit factor f = 0.03), and fails for I0X2 above 1O1S. Results for both ablation pressure and mass ablation rate are also given.

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Complex three-dimensional waves of excitation can explain the observed cell movement pattern in Dictyostelium slugs. Here we show that these three-dimensional waves can be produced by a realistic model for the cAMP relay system [Martiel, J. L. & Goldbeter, A. (1987) Biophys J. 52, 807-828]. The conversion of scroll waves in the prestalk zone of the slug into planar wave fronts in the prespore zone can result from a smaller fraction of relaying cells in the prespore zone. Further, we show that the cAMP concentrations to which cells in a slug are exposed over time display a simple pattern, despite the complex spatial geometry of the waves. This cAMP distribution agrees well with observed patterns of cAMP-regulated cell type-specific gene expression. The core of the spiral, which is a region of low cAMP concentration, might direct expression of stalk-specific genes during culmination.

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Apresenta-se neste trabalho um estudo teórico-experimental sobre a instabilidade de perfis formados a frio submetidos à flexão. A instabilidade distorcional se faz comum na presença de tensões de compressão atuando sobre perfis enrijecidos e fabricados com aços de elevada resistência mecânica. A parte teórica abrange os métodos de cálculo analíticos e numéricos para a análise de instabilidade distorcional de perfis de seção aberta formados a frio. Na parte experimental inclui-se o estudo de perfis formados a frio com seções do tipo U enrijecidos submetidos aos ensaios à flexão. Nestes ensaios variou-se a altura de alma e espessura de chapa procurando-se abranger maior número de condições geométricas para análise da estabilidade distorcional. Inclui-se também a análise de instabilidade numérica dos perfis do programa experimental através do método de resistência direta via método das faixas finitas. Com base nos resultados experimentais, numéricos e na análise teórica do problema, verificou-se o procedimento adotado pela NBR14762/2001 e efetuou-se comparação entre curvas de resistência propostas para o dimensionamento de perfis formados a frio à flexão. Foi verificado que o fenômeno de instabilidade distorcional pode ser o estado limite último crítico para o dimensionamento dos perfis formados a frio.

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This paper describes the design, tuning, and extensive field testing of an admittance-based Autonomous Loading Controller (ALC) for robotic excavation. Several iterations of the ALC were tuned and tested in fragmented rock piles—similar to those found in operating mines—by using both a robotic 1-tonne capacity Kubota R520S diesel-hydraulic surface loader and a 14-tonne capacity Atlas Copco ST14 underground load-haul-dump (LHD) machine. On the R520S loader, the ALC increased payload by 18 % with greater consistency, although with more energy expended and longer dig times when compared with digging at maximum actuator velocity. On the ST14 LHD, the ALC took 61 % less time to load 39 % more payload when compared to a single manual operator. The manual operator made 28 dig attempts by using three different digging strategies, and had one failed dig. The tuned ALC made 26 dig attempts at 10 and 11 MN target force levels. All 10 11 MN digs succeeded while 6 of the 16 10 MN digs failed. The results presented in this paper suggest that the admittance-based ALC is more productive and consistent than manual operators, but that care should be taken when detecting entry into the muck pile

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[Introduction.] Over the last two years, not only inside but also outside the framework of the EU treaties, far reaching measures have been taken at the highest political level in order to address the financial and economic crisis in Europe and in particular the sovereign debt crisis in the Euro area. This has triggered debates forecasting the “renationalisation of European politics.” Herman Van Rompuy, the President of the European Council, countered the prediction that Europe is doomed because of such a renationalisation: “If national politics have a prominent place in our Union, why would this not strengthen it?” He took the view that not a renationalisation of European politics was at stake, but an Europeanization of national politics emphasising that post war Europe was never developed in contradiction with nation states.1 Indeed, the European project is based on a mobilisation of bundled, national forces which are of vital importance to a democratically structured and robust Union that is capable of acting in a globalised world. To that end, the Treaty of Lisbon created a legal basis. The new legal framework redefines the balance between the Union institutions and confirms the central role of the Community method in the EU legislative and judiciary process. This contribution critically discusses the development of the EU's institutional balance after the entry into force of the Treaty of Lisbon, with a particular emphasis on the use of the Community Method and the current interplay between national constitutional courts and the Court of Justice. This interplay has to date been characterised by suspicion and mistrust, rather than by a genuine dialogue between the pertinent judicial actors.

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In this short review, we provide some new insights into the material synthesis and characterization of modern multi-component superconducting oxides. Two different approaches such as the high-pressure, high-temperature method and ceramic combinatorial chemistry will be reported with application to several typical examples. First, we highlight the key role of the extreme conditions in the growth of Fe-based superconductors, where a careful control of the composition-structure relation is vital for understanding the microscopic physics. The availability of high-quality LnFeAsO (Ln = lanthanide) single crystals with substitution of O by F, Sm by Th, Fe by Co, and As by P allowed us to measure intrinsic and anisotropic superconducting properties such as Hc2, Jc. Furthermore, we demonstrate that combinatorial ceramic chemistry is an efficient way to search for new superconducting compounds. A single-sample synthesis concept based on multi-element ceramic mixtures can produce a variety of local products. Such a system needs local probe analyses and separation techniques to identify compounds of interest. We present the results obtained from random mixtures of Ca, Sr, Ba, La, Zr, Pb, Tl, Y, Bi, and Cu oxides reacted at different conditions. By adding Zr but removing Tl, Y, and Bi, the bulk state superconductivity got enhanced up to about 122 K.

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In marine environments, sediments from different sources are stirred and dispersed, generating beds that are composed of mixed and layered sediments of differing grain sizes. Traditional engineering formulations used to predict erosion thresholds are however, generally for unimodal sediment distributions, and so may be inadequate for commonly occurring coastal sediments. We tested the transport behavior of deposited and mixed sediment beds consisting of a simplified two-grain fraction (silt (D50 = 55 µm) and sand (D50 = 300 µm)) in a laboratory-based annular flume with the objective of investigating the parameters controlling the stability of a sediment bed. To mimic recent deposition of particles following large storm events and the longer-term result of the incorporation of fines in coarse sediment, we designed two suites of experiments: (1) "the layering experiment": in which a sandy bed was covered by a thin layer of silt of varying thickness (0.2 - 3 mm; 0.5 - 3.7 wt %, dry weight in a layer 10 cm deep); and (2) "the mixing experiment" where the bed was composed of sand homogeneously mixed with small amounts of silt (0.07 - 0.7 wt %, dry weight). To initiate erosion and to detect a possible stabilizing effect in both settings, we increased the flow speeds in increments up to 0.30 m/s. Results showed that the sediment bed (or the underlying sand bed in the case of the layering experiment) stabilized with increasing silt composition. The increasing sediment stability was defined by a shift of the initial threshold conditions towards higher flow speeds, combined with, in the case of the mixed bed, decreasing erosion rates. Our results show that even extremely low concentrations of silt play a stabilizing role (1.4% silt (wt %) on a layered sediment bed of 10 cm thickness). In the case of a mixed sediment bed, 0.18% silt (wt %, in a sample of 10 cm depth) stabilized the bed. Both cases show that the depositional history of the sediment fractions can change the erosion characteristics of the seabed. These observations are summarized in a conceptual model that suggests that, in addition to the effect on surface roughness, silt stabilizes the sand bed by pore-space plugging and reducing the inflow in the bed, and hence increases the bed stability. Measurements of hydraulic conductivity on similar bed assemblages qualitatively supported this conclusion by showing that silt could decrease the permeability by up to 22% in the case of a layered bed and by up to 70% in the case of a mixed bed.

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Mode of access: Internet.

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Mode of access: Internet.