Search results for "Pact"
showing 10 items of 2355 documents
MR2543732 (2010g:46038) Colao, Vittorio; Trombetta, Alessandro; Trombetta, Giulio Hausdorff norms of retractions in Banach spaces of continuous funct…
2009
A retraction $R$ from the closed unit ball of a Banach space $X$ onto its boundary is called $k$-ball contractive if there is $k \ge 0$ such that $ \gamma_X(RA) \le k \gamma_X(A) $ for each subset $ A$ of the closed unit ball, where $\gamma_X$ denote the Hausdorff (ball) measure of noncompactness. In the paper under review the authors consider the problem of evaluating the Wo\'{s}ko constant, which is the infimum of all numbers $k$'s for which there is a $k$-ball contractive retraction from the closed unit ball onto the sphere, in Banach spaces of real continuous functions defined on domains which are not necessarily bounded or finite dimensional. The paper extends some previous results val…
Stochastic response of a fractional vibroimpact system
2017
Abstract The paper proposes a method to investigate the stochastic dynamics of a vibroimpact single-degree-of-freedom fractional system under a Gaussian white noise input. It is assumed that the system has a hard type impact against a one-sided motionless barrier, which is located at the system’s equilibrium position; furthermore, the system under study is endowed with an element modeled with fractional derivative. The proposed method is based on stochastic averaging technique and overcome the particular difficulty due to the presence of fractional derivative of an absolute value function; particularly an analytical expression for the system’s mean squared response amplitude is presented an…
First lamina hybridization of high performance CFRP with Kevlar fibers: Effect on impact behavior and nondestructive evaluation
2022
The impact behavior of a carbon-Kevlar hybrid composite, widely used in sport car manufacturing, was evaluated. To highlight the hybridization effect, comparative analyses were performed with the basic CFRP laminate having the same lay-up. Tensile, bending and low velocity impact tests, followed by nondestructive inspections, highlighted that Kevlar first lamina hybridization leads to an increment in specific impact strength, up to 55%. To assess the most reliable technique to detect the impact damage, nondestructive evaluation was performed by pulsed thermography, phased array ultrasonic technique, computed tomography and digital radiography. Phased array ultrasonic technique can be consid…
Carreras por montaña en la Comunitat Valenciana (1995-2019). Evolución, distribución territorial e incidencia en áreas naturales protegidas
2021
El rápido crecimiento de las carreras por montaña, ha motivado durante los últimos años su estudio. Aun son pocas las referencias bibliográficas que podemos encontrar a escala local, aunque algunas a nivel de España. Existen diferencias regionales, que demandan la necesidad de examinar este tipo de pruebas a una escala detallada. La Comunitat Valenciana, dada su extensión forestal y porcentaje de territorio montañoso (56 %), el número de espacios naturales (646) y superficie total protegida (40 %), se convierte en un buen ámbito de estudio. Una revisión bibliográfica y un análisis de la información recogida ha permitido determinar el número y la evolución de esta práctica en los últimos 25 …
Effects of Kinesiotape® taping on plantar pressure and impact acceleration during walking
2014
Summary Objectives The aim of this study was to analyse the plantar pressure pattern, contact time, stride rate and impact acceleration in the shank during walking with and without Kinesio Tape (KT®) placed on two muscle groups: peroneus and triceps surae. Methods Among the subjects, 29 (12 men, 17 women) participated in the study. KT® was placed on the triceps surae and peroneus and participants walked at two different speeds (V1: 0.73 m/s; V2: 1.30 m/s) with and without KT®. The pedobarographic system Biofoot IBV® 6.0 was used to analyse plantar pressure (mean peak pressure [kPa]) in 5 foot areas and the kinematic variables of the study (contact time [s]; stride rate [steps/second]). One …
I traffici illeciti nel Mediterraneo. Persone, stupefacenti, tabacco
2019
Attraverso la combinazione di ricerca criminologica e giuridico-normativa, e grazie anche alla collaborazione con esperti esterni (studiosi, magistrati, rappresentanti di istituzioni italiane e straniere), la ricerca da cui scaturisce il volume ha indagato le interazioni tra i diversi traffici illeciti e la criminalità organizzata nel bacino del Mediterraneo. In tale area, storicamente cruciale per la mobilità di persone e di beni, l’attenzione si è rivolta in particolare ai fenomeni del traffico e della tratta di persone, del traffico di stupefacenti e del contrabbando di sigarette. I contributi raccolti – unitamente al rapporto criminologico e ai cinque rapporti nazionali accessibili su w…
Ecosystem responses to land abandonment in Western Mediterranean Mountains
2017
Agricultural expansion in the Mediterranean resulted in plant and soil degradation due to the intensive use, climate conditions, and rugged terrain. After abandonment, the recovery of vegetation contributed to improvement in soil quality from a hydrological, pedological and geomorphological point of view. This paper shows three examples of ecosystem evolution in abandoned fields in Valencia, Murcia and Andalucia and the application of different methodological approaches that resulted in similar findings. In Valencia, the main responses were the recovery of vegetation after land abandonment and an increase in organic matter and infiltration capacity of soils. In Murcia, with the exception of…
Mount Etna volcano (Italy) as a major “dust” point source in the Mediterranean area
2016
Volcanic emissions represent one of the most relevant natural sources of trace elements to the troposphere. Due to their potential toxicity, they may have important environmental impacts from local to global scale. They can also severely affect the atmospheric and terrestrial environment at timescales ranging from a few to millions of years. Mt. Etna volcano is known as one of the largest global contributors of magmatic gases (CO2, SO2 and halogens) and particulate matter, including some toxic trace elements. The aim of this study is to characterize the chemical composition and the mineralogical features of the volcanogenic aerosol passively emitted from Mt. Etna. Twenty-five samples were c…
8000 years of coastal changes on a western Mediterranean island: A multiproxy approach from the Posada plain of Sardinia
2018
Abstract A multi-proxy palaeoenvironmental investigation was conducted to reconstruct the Holocene history of coastal landscape change in the lower Posada coastal plain of eastern Sardinia. In the Mediterranean region, coastal modifications during the Holocene have been driven by a complex interplay between climate, geomorphological processes and human activity. In this paper, millennial-scale human-sea level-environment interactions are investigated near Posada, one of the largest coastal plains in eastern Sardinia. Biostratigraphic and palynological approaches were used to interpret the chrono-stratigraphy exhibited by a series of new cores taken from the coastal plain. This new study elu…
Mid- and late-Holocene vegetation and fire history at Biviere di Gela, a coastal lake in southern Sicily, Italy
2009
The vegetation and fire history of few coastal sites has been investigated in the Mediterranean region so far. We present the first paleoecological reconstruction from coastal Sicily, the largest island in the Mediterranean Sea. We analysed pollen and charcoal in the sediments of Biviere di Gela, a lake (lagoon) on the south coast of Sicily. Our data suggest that the area became afforested after a marine transgression at ca. 7200 cal b.p. (5250 b.c.). Build-up of forest and shrublands took ca. 200–300 years, mainly with the deciduous trees Quercus, Ostrya and Fraxinus. Juniperus expanded ca. 6900 cal b.p. (4950 b.c.), but declined again 6600 cal b.p. (4650 b.c.). Afterwards, evergreen trees…