Design issues of a variable thermal resistance

Some years ago we have proposed a thermal mount with electronically variable thermal resistance [1]. In this earlier work the feasibility of such a structure has been demonstrated. Now we intend to realize this mount in a maturated form, suitable to the everyday use in the practice of package thermal qualification and modeling. The design of such a device raises a number of new questions and problems. The present paper is dealing with these problems and the possible solutions.Comment: Submitted on behalf of TIMA Editions (http://irevues.inist.fr/tima-editions

Evaluation of a locally homogeneous flow model of spray combustion

A model of spray combustion which employs a second-order turbulence model was developed. The assumption of locally homogeneous flow is made, implying infinitely fast transport rates between the phase. Measurements to test the model were completed for a gaseous n-propane flame and an air atomized n-pentane spray flame, burning in stagnant air at atmospheric pressure. Profiles of mean velocity and temperature, as well as velocity fluctuations and Reynolds stress, were measured in the flames. The predictions for the gas flame were in excellent agreement with the measurements. The predictions for the spray were qualitatively correct, but effects of finite rate interphase transport were evident, resulting in a overstimation of the rate development of the flow. Predictions of spray penetration length at high pressures, including supercritical combustion conditions, were also completed for comparison with earlier measurements. Test conditions involved a pressure atomized n-pentane spray, burning in stagnant air at pressures of 3, 5, and 9 MPa. The comparison between predictions and measurements was fair. This is not a very sensitive test of the model, however, and further high pressure experimental and theoretical results are needed before a satisfactory assessment of the locally homogeneous flow approximation can be made

Oxidation of 3,5-di-tert-butylcatechol and 2-aminophenol by molecular oxygen catalyzed by an organocatalyst

1,3,2-Oxazaphospholes are able to catalyze the oxidation of 3,5-di- tert -butylcatechol with 3 O 2 to the corresponding o -quinone and 2-aminophenol to 2-aminophenoxazine-3-one in methanol. In both the cases, an overall third order reaction rate equation and a new type of biomimetic organocatalyst for oxidation reactions was found. A one electron transfer of the phenolate, which is formed through the deprotonation of the substrates by the catalyst, to dioxygen seems to be rate-determining step

Intensity-based elastic registration incorporating anisotropic landmark errors and rotational information

Purpose: Thin-plate splines (TPS) represent an effective tool for estimating the deformation that warps one set of landmarks to another based on the physical equivalent of thin metal sheets. In the original formulation, data used to estimate the deformation field are restricted to landmark locations only and thus does not allow to incorporate information about the rotation of the image around the landmark. It furthermore assumes that landmark positions are known exactly which is not the case in real world applications. These localization inaccuracies are propagated to the entire deformation field as each landmark has a global influence. We propose to use a TPS approximation method that incorporates anisotropic landmark errors and rotational information and integrate it into a hierarchical elastic registration framework (HERA). The improvement of the registration performance has been evaluated. Methods: The proposed TPS approximation scheme integrates anisotropic landmark errors with rotational information of the landmarks. The anisotropic landmark errors are represented by their covariance matrices estimated directly from the image data as a minimal stochastic localization error, i.e. the Cramér-Rao bound. The rotational attribute of each landmark is characterized by an additional angular landmark, thus doubling the number of landmarks in the TPS model. This allows the TPS approximation to better cope up with local deformations. Results: We integrated the proposed TPS approach into the HERA registration framework and applied it to register 161 image pairs from a digital mammogram database. Experiments showed that the mean squared error using the proposed TPS approximation was superior to pure TPS interpolation. On artificially deformed breast images HERA, with the proposed TPS approximation, performed significantly better than the state-of-the-art registration method presented by Rueckert. Conclusion: The TPS approximation approach proposed in this publication allows to incorporate anisotropic landmark errors as well as rotational information. The integration of the method into an intensity-based hierarchical non-rigid registration framework is straightforward and improved the registration quality significantl

Activity of 50 Long-Period Comets Beyond 5.2 AU

Remote investigations of the ancient solar system matter has been traditionally carried out through the observations of long-period (LP) comets that are less affected by solar irradiation than the short-period counterparts orbiting much closer to the Sun. Here we summarize the results of our decade-long survey of the distant activity of LP comets. We found that the most important separation in the dataset is based on the dynamical nature of the objects. Dynamically new comets are characterized by a higher level of activity on average: the most active new comets in our sample can be characterized by afrho values >3--4 higher than that of our most active returning comets. New comets develop more symmetric comae, suggesting a generally isotropic outflow. Contrary to this, the coma of recurrent comets can be less symmetrical, ocassionally exhibiting negative slope parameters, suggesting sudden variations in matter production. The morphological appearance of the observed comets is rather diverse. A surprisingly large fraction of the comets have long, teniouos tails, but the presence of impressive tails does not show a clear correlation with the brightness of the comets.Comment: 21 pages, 4 figures, accepted for publication in A

ArCo: the Italian Cultural Heritage Knowledge Graph

ArCo is the Italian Cultural Heritage knowledge graph, consisting of a network of seven vocabularies and 169 million triples about 820 thousand cultural entities. It is distributed jointly with a SPARQL endpoint, a software for converting catalogue records to RDF, and a rich suite of documentation material (testing, evaluation, how-to, examples, etc.). ArCo is based on the official General Catalogue of the Italian Ministry of Cultural Heritage and Activities (MiBAC) - and its associated encoding regulations - which collects and validates the catalogue records of (ideally) all Italian Cultural Heritage properties (excluding libraries and archives), contributed by CH administrators from all over Italy. We present its structure, design methods and tools, its growing community, and delineate its importance, quality, and impact

A Test of Independence in Two-Way Contingency Tables Based on Maximal Correlation

Cataloged from PDF version of article.Maximal correlation has several desirable properties as a measure of dependence, including the fact that it vanishes if and only if the variables are independent. Except for a few special cases, it is hard to evaluate maximal correlation explicitly. We focus on two-dimensional contingency tables and discuss a procedure for estimating maximal correlation, which we use for constructing a test of independence. We compare the maximal correlation test with other tests of independence by Monte Carlo simulations. When the underlying continuous variables are dependent but uncorrelated, we point out some cases for which the new test is more powerful

The Szemeredi-Trotter Theorem in the Complex Plane

It is shown that $n$ points and $e$ lines in the complex Euclidean plane ${\mathbb C}^2$ determine $O(n^{2/3}e^{2/3}+n+e)$ point-line incidences. This bound is the best possible, and it generalizes the celebrated theorem by Szemer\'edi and Trotter about point-line incidences in the real Euclidean plane ${\mathbb R}^2$.Comment: 24 pages, 5 figures, to appear in Combinatoric

Suicide methods in Europe: a gender-specific analysis of countries participating in the "European Alliance Against Depression"

Objective: To identify the most frequent gener-specific suicide methods in Europe. Design: Proportions of seven predominant suicide methods utilised in 16 countries participating in the European Alliance Against Depression (EAAD)were reported in total and cross-nationally. Relative risk (RR)relating to suicide methods and gender was calculated. To group countries by pattern of suicide methods, hierarchical clustering was applied. Setting and participants: Data on suicide methods for 119 122 male and 41 338 female cases in 2000-4/5 from 16 EAAD countries, covering 52% of European population were obtained. Results: Hanging was the most prevalent suicide method among both males (54.3%) and females (35.6%). For males, hanging was followed by firearms (9.7%) and poisoning by drugs (8.6%); for females, by poisoning by drugs (24.7%)and jumping from a high place (14.5%). Only in Switzerland did hanging rank as second for males after firearms. Hanging ranked first among females in eight countries, poisoning by drugs in five and jumping from a high place in three. In all countries, males had a higher risk than females of using firearms and hanging and a lower risk of poisoning by drugs, drowning and jumping. Grouping showed that countries might be divided into five main groups among males; for females, grouping did not yield clear results. Conclusions: Research on suicide methods could lead to the development of gender-specific intervention strategies. Nevertheless, other approaches, such as better identification and treatment of mental disorders and the improvement of toxicological aid should be put in place