Critical analysis on the use of the shove test for investigating the shear-sliding behavior of brick masonry

The shove test (ASTM Standard C1531) is an experimental technique aimed at studying the shear-sliding behavior of brick masonry. It can be executed according to various testing methods that differ in the way the vertical compression load is applied and in the way bricks and/or joints are locally removed for inserting jacks. One of the most critical aspects is the correct evaluation of the compressive stress state on the sliding brick. The objective of the present paper is to investigate the capability of the shove test in determining the shear strength parameters of brick masonries and to highlight the main advantages and disadvantages of the various testing methods. To this aim, nonlinear numerical simulations of the shove test were performed by adopting a brick-to-brick modeling strategy. The 2D numerical model was calibrated and validated through comparisons with experimental results of triplet tests and shove tests. The numerical analyses allowed to understand the influence the different testing methods and the masonry mechanical properties, such as dilatancy, may have on the test results. Based on the numerical outcomes, correction factors were calibrated for the proper evaluation of the compressive stress state on the sliding brick. Improvements with regards to the experimental procedures, i.e. additional test phases and measurements, were also proposed to enhance the results interpretation

Chemical enrichment of the complex hot ISM of the Antennae galaxies: I. Spatial and spectral analysis of the diffuse X-ray emission

We present an analysis of the properties of the hot interstellar medium (ISM) in the merging pair of galaxies known as The Antennae (NGC 4038/39), performed using the deep, coadded ~411 ks Chandra ACIS-S data set. These deep X-ray observations and Chandra's high angular resolution allow us to investigate the properties of the hot ISM with unprecedented spatial and spectral resolution. Through a spatially resolved spectral analysis, we find a variety of temperatures (from 0.2 to 0.7 keV) and Nh (from Galactic to 2x10^21 cm^-2). Metal abundances for Ne, Mg, Si, and Fe vary dramatically throughout the ISM from sub-solar values (~0.2) up to several times solar.Comment: 33 pages, 18 figures, revised version accepted by Astrophysical Journal Supplement Serie

Regulatory Impact Assessment: A survey of selected developing and emerging economies

Regulatory impact assessment (RIA) involves a systematic appraisal of the social, economic and environmental impacts of proposed regulations and other kinds of policy instruments before they are adopted. A vast amount of academic literature in the last decade has charted the diffusion of RIA in OECD countries and EU member states. However, relatively little is known about the extent to which RIA has been adopted and implemented in developing countries. The last research attempting to shed light on this issue over a decade ago found that a number of were beginning to apply some form of regulatory assessment but that its development was at an early stage. Since then RIA has become almost universally adopted in OECD and EU member states as well as promoted as a tool for good (regulatory) governance in developing countries by international donors and organizations such as OECD, the International Finance Corporation of the World Bank Group (IFC). What, then, is the extent of RIA adoption and implementation in these countries today? This working paper addresses this question through a survey of RIA in 14 developing and emerging economies based on documentary analysis as well as semi-structured interviews with key stakeholders. The survey explores topics such as the legal and institutional framework of RIA, organizational capacity, and use of tools and methods (e.g. Cost Benefit Analysis). The results suggest that while an increasing number of developing countries have made efforts to introduce RIA in their decision making processes, these efforts have not yet led to a sustainable RIA system which significantly contributes to the good regulatory governance of these countries

Preventie op de camping:Resultaten van twee pilots in West-Brabant in het souterrain van de woningmarkt

Vanwege tekorten op de woningmarkt enerzijds en de moeizame exploitatie van recreatieparken anderzijds, is permanente bewoning op recreatieparken een structureel maatschappelijk verschijnsel geworden. Permanente bewoning is wettelijk niet toegestaan en kan samengaan met diverse vormen van sociale problematiek. De sociale crisis die ontstond op camping Fort Oranje is voor de GGD WestBrabant aanleiding geweest preventieve werkwijzen voor recreatieparken te ontwikkelen. Dit artikel beschrijft twee pilots die in dit verband werden opgezet. De ambitie was bewoners van recreatieparken in beeld te krijgen en waar nodig te ondersteunen, en om een stem te geven aan hun verhaal

Simultaneous Absolute Timing of the Crab Pulsar at Radio and Optical Wavelengths

The Crab pulsar emits across a large part of the electromagnetic spectrum. Determining the time delay between the emission at different wavelengths will allow to better constrain the site and mechanism of the emission. We have simultaneously observed the Crab Pulsar in the optical with S-Cam, an instrument based on Superconducting Tunneling Junctions (STJs) with $\mu$s time resolution and at 2 GHz using the Nan\c{c}ay radio telescope with an instrument doing coherent dedispersion and able to record giant pulses data. We have studied the delay between the radio and optical pulse using simultaneously obtained data therefore reducing possible uncertainties present in previous observations. We determined the arrival times of the (mean) optical and radio pulse and compared them using the tempo2 software package. We present the most accurate value for the optical-radio lag of 255 $\pm$ 21 $\mu$s and suggest the likelihood of a spectral dependence to the excess optical emission asociated with giant radio pulses.Comment: 8 pages; accepted for publication in Astronomy and Astrophysic

Chemical enrichment of the complex hot ISM of the Antennae Galaxies: II. Physical properties of the hot gas and supernova feedback

We investigate the physical properties of the interstellar medium (ISM) in the merging pair of galaxies known as The Antennae (NGC 4038/39), using the deep coadded ~411 ks Chandra ACIS-S data set. The method of analysis and some of the main results from the spectral analysis, such as metal abundances and their variations from ~0.2 to ~20-30 times solar, are described in Paper I (Baldi et al. submitted). In the present paper we investigate in detail the physics of the hot emitting gas, deriving measures for the hot-gas mass (~10^ M_sun), cooling times (10^7-10^8 yr), and pressure (3.5x10^-11-2.8x10^-10 dyne cm^-2). At least in one of the two nuclei (NGC 4038) the hot-gas pressure is significantly higher than the CO pressure, implying that shock waves may be driven into the CO clouds. Comparison of the metal abundances with the average stellar yields predicted by theoretical models of SN explosions points to SNe of Type II as the main contributors of metals to the hot ISM. There is no evidence of any correlation between radio-optical star-formation indicators and the measured metal abundances. Although due to uncertainties in the average gas density we cannot exclude that mixing may have played an important role, the short time required to produce the observed metal masses (<=2 Myr) suggests that the correlations are unlikely to have been destroyed by efficient mixing. More likely, a significant fraction of SN II ejecta may be in a cool phase, in grains, or escaping in hot winds. In each case, any such fraction of the ejecta would remain undetectable with soft X-ray observations.Comment: 29 pages, 6 figures, accepted by the Astrophysical Journa

The Shearing HI Spiral Pattern of NGC 1365

The Tremaine-Weinberg equations are solved for a pattern speed that is allowed to vary with radius. The solution method transforms an integral equation for the pattern speed to a least squares problem with well established procedures for statistical analysis. The method applied to the HI spiral pattern of the barred, grand-design galaxy NGC 1365 produced convincing evidence for a radial dependence in the pattern speed. The pattern speed behaves approximately as 1/r, and is very similar to the material speed. There are no clear indications of corotation or Lindblad resonances. Tests show that the results are not selection biased, and that the method is not measuring the material speed. Other methods of solving the Tremaine-Weinberg equations for shearing patterns were found to produce results in agreement with those obtained using the current method. Previous estimates that relied on the assumptions of the density-wave interpretation of spiral structure are inconsistent with the results obtained using the current method. The results are consistent with spiral structure theories that allow for shearing patterns, and contradict fundamental assumptions in the density-wave interpretation that are often used for finding spiral arm pattern speeds. The spiral pattern is winding on a characteristic timescale of ~ 500 Myrs.Comment: Accepted for publication in The Astrophysical Journa