Surface Photometry of Early-type Galaxies in the Hubble Deep Field

The detailed surface photometry of a sample of early-type galaxies in the Hubble Deep Field is presented as part of a long-term project aimed to settle strong observational constraints to the theories modelling the evolution of elliptical galaxies from the early stages. The sample has been extracted, in the V_606 band, from the catalog by Couch (1996). The analysis of the luminosity and geometrical profiles, carried out on 162 candidates obeying our provisional selection criteria, resulted in a list of 99 'bona fide' early-type galaxies, for which accurate total magnitudes and effective radii were computed. The comparison with the magnitudes given by Williams et al.(1996) indicates that the automated photometry tends to underestimate the total luminosity of the ellipticals. The luminosity profiles of most of galaxies in our sample follow fairly well the deVaucouleurs law (`Normal' profiles). However, a relevant fraction of galaxies, even following the deVaucouleurs law in the main body light distribution, exhibit in the inner region a flattening of the luminosity profile not attributable to the PSF (`Flat' profiles) or, in some cases, a complex (multi-nucleus) structure (`Merger' profiles). The average ellipticity of galaxies belonging to the `Flat' and `Merger' classes is found to be significantly higher than that of the `Normal' galaxies. Moreover, even taken into account the relevant uncertainty of the outer position angle profiles, the amount of isophotal twisting of HDF ellipticals turns out to be significantly larger with respect to that of the local samples.Comment: 22 pages, LaTeX with laa.sty and psfig.sty macros + 28 embedded postscript figures. To appear in Astronomy and Astrophysics Supp

Preliminary validation of an indirect method for discharge evaluation of Pertuso Spring (Central Italy)

This paper deals with the results of the first year of the Environmental Monitoring Plan, related to the catchment project of Pertuso Spring, which is going to be exploited to supply an important water network in the South part of Roma district. The study area is located in the Upper Valley of the Aniene River (Latium, Central Italy), in the outcrop of Triassic-Cenozoic carbonate rocks, and belong to an important karst aquifer. Pertuso Spring is the main outlet of this karst aquifer and is the one of the most important water resource in the southeast part of Latium Region, used for drinking, agriculture and hydroelectric supplies. Karst aquifer feeding Pertuso Spring is an open hydrogeological system aquifer characterized by complex interactions and exchanges between groundwater and surface water which influence the aquifer water budget. Thus, evaluation of groundwater discharge from this karst spring can be affected by difficulties in performing measurements because of the insufficient knowledge about water transfer processes in the hydrological cycle and geometry of drainage conduits. The aim of this paper is to assess the interactions between karst aquifer feeding Pertuso Spring and Aniene River based on stream discharge measurements and water geochemical tracer data in order to validate an indirect method for karst spring discharge evaluation. As a matter of fact, in this paper, there are presented the results of the application of Magnesium as a reliable tracer of karst spring discharge. This indirect method is based on the elaboration of surface water discharge measurements in relationship with Mg2+ concentration values, determined as for groundwater, coming from Pertuso Spring, as for surface water sample, collected upstream and downstream of Pertuso Spring, along Aniene River streamflow. The application of Magnesium as an environmental tracer provides a means to evaluate discharge of Pertuso Spring, as it came up to be a marker of the mixing of surface water and groundwater. On the other hand, the Magnesium ion concentration provides information for the identification of groundwater flow systems and the main hydrogeochemical processes affecting the composition of water within the karst aquifers

High-Fidelity 1D and 2D Models for Static and Dynamic Analyses of Wind Turbine Rotor Blades

Wind energy is an essential renewable source to tackle the most critical environmental problems, such as global warming. Recently, the wind blade size has been increasing to maximize turbine efficiency. However, increased dimensions lead to further design challenges due to severe loadings - inertial and aerodynamic - and unavoidable manufacturing complexities. Therefore, extensive simulation campaigns covering as many operational conditions as possible become crucial for sustainable design and manufacturing. Various numerical tools for this purpose have been proposed to predict the response and damage levels of sizeable composite wind turbine blades. Within this context, this paper presents results based on the Carrera Unified Formulation (CUF) on various blade configurations. The CUF is a hierarchical formulation providing classical and higher-order beam, plate, and shell models using arbitrary kinematic expansions. The one-dimensional (1D) and two-dimensional (2D) CUF-based models can ensure a similar accuracy of three-dimensional (3D) solutions with considerable savings in computational efforts. The principle of virtual work and a finite element approximation is used to formulate both geometrically linear and nonlinear governing equations. The numerical results focus on static, dynamic, and failure analyses performed on composite wind turbine blades. The failure index evaluation uses a global/local approach that combines the CUF models with conventional FE solutions. In addition, future challenges related to health monitoring, damage detection, and developing a digital twin for structural verification will be discussed

Interfacial contribution to the dielectric response in semiconducting LaBiMn4/3Co2/3O6

Impedance measurements have been performed on a sintered polycrystalline sample of the perovskite LaBiMn4/3Co2/3O6. Colossal dielectric permittivity often is measured in this class of semiconducting materials as a result of extrinsic factors. Our results show that a large offset in the capacitance, measured on a series of samples with different thickness, is due to the interfacial polarization. This contribution then can be removed from the data, creating a general procedure for dielectric measurements in semiconducting samples.Comment: 13 pages, 4 figure

dentate nucleus t1 hyperintensity in multiple sclerosis

Gray matter (GM) damage, in terms of focal lesions,[1][1] "diffuse" tissue injury, and atrophy is a well-known feature of multiple sclerosis (MS). Recently, T1-hyperintensity on unenhanced T1-weighted sequences has been found in the dentate nuclei of patients with MS with severe disability an

mr imaging of gray matter involvement in multiple sclerosis implications for understanding disease pathophysiology and monitoring treatment efficacy

SUMMARY: Recent pathologic and MR imaging studies have challenged the classic view of MS as a chronic inflammatory-demyelinating condition affecting solely the WM of the central nervous system. Indeed, an involvement of the GM has been shown to occur from the early stages of the disease, to progress with time, and to be only moderately correlated with the extent of WM injury. In this review, we summarize how advances in MR imaging technology and methods of analysis are contributing to ameliorating the detection of focal lesions and to quantifying the extent of "occult" pathology and atrophy, as well as to defining the topographic distribution of such changes in the GM of patients with MS. These advances, combined with the imaging of brain reorganization occurring after tissue injury, should ultimately result in an improved understanding and monitoring of MS clinical manifestations and evolution, either natural or modified by treatment. Cereb : cerebellum Cho : choline CIS : clinically isolated syndromes DIR : double inversion recovery DTI : diffusion tensor imaging EDSS : Expanded Disability Status Scale FA : fractional anisotropy FLAIR : fluid-attenuated inversion recovery fMRI : functional MR imaging GM : gray matter L : left MD : mean diffusivity MS : multiple sclerosis MT : magnetization transfer MTR : magnetization transfer ratio NAA : N -acetylaspartate NAWM : normal-appearing white matter PM : premotor cortex PPMS : primary-progressive MS R : right RRMS : relapsing-remitting MS RT : relaxation time SII : secondary sensorimotor cortex SMA : supplementary motor area SMC : sensorimotor cortex SPM : statistical parametric mapping SPMS : secondary-progressive MS Thal : thalamus WM : white matte

dirty appearing white matter a disregarded entity in multiple sclerosis

In patients with multiple sclerosis (MS), the term dirty-appearing white matter (DAWM) refers to brain regions of intermediate signal intensity between those of focal lesions and normal-appearing white matter (NAWM) on T2-weighted and proton attenuation–weighted images.[1][1][][2][][3]–[4][4

TDNiCr (ni-20Cr-2ThO2) forging studies

Elevated temperature tensile and stress rupture properties were evaluated for forged TDNiCr (Ni-20Cr-2ThO2) and related to thermomechanical history and microstructure. Forging temperature and final annealed condition had pronounced influences on grain size which, in turn, was related to high temperature strength. Tensile strength improved by a factor of 8 as grain size changed from 1 to 150 microns. Stress-rupture strength was improved by a factor of 3 to 5 by a grain size increase from 10 to 1000 microns. Some contributions to the elevated temperature strength of very large grain material may also occur from the development of a strong texture and a preponderance of small twins. Other conditions promoting the improvement of high temperature strength were: an increase of total reduction, forging which continued the metal deformation inherent in the starting material, a low forging speed, and prior deformation by extrusion. The mechanical properties of optimally forged TDNiCr compared favorably to those of high strength sheet developed for space shuttle application

Arc melting and properties of two chromium- base alloys Final report

Arc melting, microstructure, mechanical properties and metallography of two chromium based alloy