Effect of surface roughness on the 0.66-micron normal spectral emittance of vapor-deposited rhenium from 1500 deg K to 2100 deg K

Surface roughness effects on normal spectral emittance of vapor deposited rheniu

Social Interactions in Schooling

We exploit the 1980 earthquake in southern Italy and the subsequent relief from mandatory military service granted to all males in the regions hit by the seism to estimate the strength of endogenous social interactions in schooling achievements. Preliminary results point to a significant and strong effect of interactions not mediated by marketsEndogenous interactions, schooling, peer-effect.

Chiral three-nucleon forces and the evolution of correlations along the oxygen isotopic chain

The impact of three-nucleon forces (3NFs) along the oxygen chain is investigated for the spectral distribution for attachment and removal of a nucleon, spectroscopic factors and matter radii. We employ self-consistent Green's function (SCGF) theory which allows a comprehensive calculation of the single particle spectral function. For the closed subshell isotopes, $^{14}$O, $^{16}$O, $^{22}$O, $^{24}$O and $^{28}$O, we perform calculations with the Dyson-ADC(3) method. The remaining open shell isotopes are studied using the newly developed Gorkov-SCGF formalism up to second order. We produce plots for the full-fledged spectral distributions. The spectroscopic factors for the dominant quasiparticle peaks are found to depend very little on the leading order (NNLO) chiral 3NFs. The latters have small impact on the calculated matter radii, which, however are consistently obtained smaller than experiment. Similarly, single particle spectra tend to be diluted with respect to experiment. This effect might hinder, to some extent, the onset of correlations and screen the quenching of calculated spectroscopic factors. The most important effects of 3NFs is thus the fine tuning of the energies for the dominant quasiparticle states, which govern the shell evolution and the position of driplines. Although present chiral NNLO 3NFs interactions do reproduce the binding energies correctly in this mass region, the details of the nuclear wave function remain at odd with the experiment showing too small radii and a too dilute single particle spectrum, similar to what already pointed out for larger masses. This suggests a lack of repulsion in the present model of NN+3N interactions which is mildly apparent already for masses in the A=14--28 range.Comment: 13 pages, accepted for publication on Phys. Rev.

The Liabilities of Sureties

This paper provides an overview of when a surety may be released from his or her obligations under a guarantee following a material variation to the principal lending contract. Part I frames the overall discussion by reviewing the role and importance of guarantees in contemporary commerce, outlining the central tenets of guarantee obligations, and distinguishing them as a subset of indemnities. Part II reviews how sureties have traditionally enjoyed a favoured status at law as well as what, in law, is considered to constitute a material variation. Part III introduces and sets out a longstanding rule governing the liability of sureties following a material variation to the principal contract. Part III examines the decisions of the Supreme Court of Canada in Manulife Bank of Canada v Conlin and the Ontario Court of Appeal in Bank of Montreal v Negin and illustrates how the courts, under similar factual circumstances, arrived at conflicting outcomes. Part III summarizes the jurisprudence in Ontario following these decisions to show that most decisions have distinguished the Supreme Court of Canada’s judgment in Conlin on the grounds that later guarantees have not been prone to the same inconsistencies. This argument is bolstered by an in-depth review of the Ontario Court of Appeal’s recent decision in Royal Bank of Canada v Samson Management & Solutions, wherein the Court distinguished that case from Conlin and held the surety liable under her guarantee

Toward the Ab-initio Description of Medium Mass Nuclei

As ab-initio calculations of atomic nuclei enter the A=40-100 mass range, a great challenge is how to approach the vast majority of open-shell (degenerate) isotopes. We add realistic three-nucleon interactions to the state of the art many-body Green's function theory of closed-shells, and find that physics of neutron driplines is reproduced with very good quality. Further, we introduce the Gorkov formalism to extend ab-initio theory to semi-magic, fully open-shell, isotopes. Proof-of-principle calculations for Ca-44 and Ni-74 confirm that this approach is indeed feasible. Combining these two advances (open-shells and three-nucleon interactions) requires longer, technical, work but it is otherwise within reach.Comment: Contribution to Summary Report of EURISOL Topical and Town Meetings, 15-19 October 2012; missing affiliations added and corrected errors in Tab

Market frictions in entrepreneurial innovation: Theory and evidence

We propose a model of entrepreneurial innovation that rationalizes its pattern of boom and bust. In the model, a successful entrepreneurial project is the result of a search and matching process between entrepreneurs and capitalists. A strategic complementarity between the entrepreneurs\u2019 demand for funds and the capitalists\u2019 supply arises both on the extensive and on the intensive margin. Using data from the Global Entrepreneurship Monitor, and collecting data on the venture capital market of 23 OECD countries plus China for the period 2007\u20132015, we find robust evidence of complementarity across the two sides of the market. We also provide a quantitative estimate of a multiplier effect originating from such complementarity

Development and calibration of a 1D thermo-fluid dynamic model of ventilation in tunnels

In complex, large civil infrastructures where ventilation has a crucial role for the safety of users in both normal operation and hazardous scenarios, the correct prediction of flow and heat transfer parameters is of fundamental importance. While full 3D simulation is applicable only to a limited extent, and the resort to 1D modeling is a common practice in both design and evaluation phases, the limitation of such models lies in the choice of transfer parameters, such as friction loss coefficients and heat transfer coefficients. In this work, an original approach based on the Finite Volume integration of the 1D flow and energy equations is presented. Such equations are to be solved on a network of ducts, representing the ventilation system in the 11.6 km long Mont Blanc Tunnel with a spatial resolution of 10 m. A preliminary calibration of a set of friction loss coefficients against a rich experimental dataset collected throughout a dedicated set of in situ tests is of particular concern here, as it is carried out by means of genetic optimization algorithms. Predictions of the flow field are in remarkable agreement with the experimental data, with an overall RMS error of - 0.42 m/s. Further refinements and possible parameter choices are also discussed

An integrated approach for the analysis and modeling of road tunnel ventilation. Part I: Continuous measurement of the longitudinal airflow profile

The knowledge of the flow field inside road tunnels under normal operation, let alone fire conditions, is only approximate and partial. The reason is that while the full three-dimensional, unsteady problem is out of reach of numerical methods, on the other hand accurate measurement of the airflow in road and railway tunnels constitutes an extremely demanding task. The present work, structured as a twofold study, takes up the challenge and proposes an original integrated experimental and numerical approach for the analysis and modeling of flow inside a road tunnel and its ventilation systems, aiming at defining a methodology for the creation of “digital twins” of the system itself, on which advanced ventilation and smoke control strategies can be tested and fine-tuned. In this first part, an innovative experimental facility for the continuous acquisition of the longitudinal velocity profile along the whole length of a road tunnel has been designed and built. The facility consists of a survey rake with five bidirectional vane anemometers, which is mounted on a small electric vehicle that can travel through the tunnel at constant speed. This paper reports the design procedure of the measurement facility, with particular focus on the conception and realization of the vehicle carrying the survey rake. Results of the first experimental campaign carried out under the 11611 meters long Mont Blanc road tunnel are presented to corroborate the validity of the approach adopted and the accuracy of the measurement chain

An integrated approach for the analysis and modeling of road tunnel ventilation. Part II: Numerical model and its calibration

The present work represents the second and final part of a twofold study aiming at the definition and validation of an integrated methodology for the analysis and modeling of road tunnel ventilation systems. A numerical approach is presented, based on the Finite Volume integration of the 1D mechanical and thermal energy conservation equations on a network of ducts, representing the ventilation system of the 11.6 km long Mont Blanc Tunnel. The set of distributed and concentrated loss coefficients, representing dissipation of mechanical energy by friction in each part of the ventilation system, is calibrated against a rich experimental dataset, collected throughout a dedicated set of in situ tests and presented in the first part of the work. The calibration of the model is carried out by means of genetic optimization algorithms. Predictions of the flow field using the calibrated parameters are in remarkable agreement with the experimental data, with an overall RMS error of \ub1 0.27 m/s, i.e. of the same order of the accuracy of the measurement probes. Further validation against a selection of field data recorded by the tunnel monitoring and control system is brought forward, highlighting the robustness and potential general applicability of the proposed approach