723 research outputs found
Energy of a non-linear viscoelastic model compatible with fractional relaxation
Recently, a non-linear model of viscoelasticity based on Rational Extended
Thermodynamics was proposed in [arXiv:2312.05116]. This theory extends the
evolution of the viscous stress beyond the linear framework of the Maxwell
model to the non-linear realm, provided that the viscous energy function is
given. This work aims at establishing a possible constitutive law for the
viscous energy such that the relaxation modulus of the fractional Maxwell model
of order is contained within the solutions of the
(non-linear) relaxation experiment. Necessary and sufficient conditions for the
existence of this coincident solution are discussed, together with a numerical
evaluation of the viscous energy associated with the non-linear model.Comment: 8 pages, 3 figure
Kinds of blue : diversity in UN peacekeeping missions and civilian protection
For a given number of troops in a peace operation, is it advisable to have soldiers from a single country, or should the UN recruit peacekeepers from a variety of donor countries? Since 1990, the number of contributors to peace operations has grown threefold, and most operations have carried the mandate to protect civilians. This article explores the effect of diversity in the composition of a mission, measured by fractionalization and polarization indices, on its performance in protecting civilians in Africa in the period 1991â2008. It finds that mission diversity decreases the level of violence against civilians, a result that holds when geographic and linguistic distances between countries are considered
Peacekeeping effectiveness and Blue Helmetsâ distance from locals
United Nations (UN) peacekeeping missions are complex social organizations, with soldiers coming from several countries. In this environment, effective communication and interactions with local populations are often difficult, and establishing essential local support can be jeopardized when soldiers are culturally distant from local communities. At the same time, however, when local populations perceive peacekeepers as sufficiently distant or unbiased, the promotion of cooperation is enhanced. We explore whether cultural distanceâin terms of geography, language, and religionâand social distanceâin terms of economy and institutionsâbetween the peacekeepers and the local population improve the operational capabilities of a mission. We use monthly information on UN peacekeeping missionsâ composition from 1990 to 2015. We find that higher geographic and cultural distances correspond to higher levels of violence against civilians and higher battle deaths, whereas institutional and economic differences have the opposite effects, although these are less robust
Ruptured middle cerebral artery aneurysms. retrospective study and multivariate analysis of 105 patients treated by surgical clipping
Objective of the study: We analyze in this study only patients with surgically treated ruptured aneurysms in order to identify statistical significance of each predictive factor in terms of outcome of patients with ruptured MCAAs. Materials and methods: In this retrospective study, we analyzed 105 cases of ruptured MCAAs, admitted from January 2001 to December 2015 at Neurosurgical Department of Umberto I University Hospital of Rome, Italy. Predictive factors evaluated are: Patientâs features (age, sex, co-morbidities), aneurysmal location (proximal, bifurcation or distal) and size of aneurysmal dome (small, large or giant); surgical timing (ultra-early, early, delayed), and Intracerebral Hemorrhage (ICH) volume. For each parameter we calculated mean and standard deviation, covariance and relation coefficient (through the linear regression model). Results: The clinical evaluation of patients assessed through the World Federation of Neurological Surgeons (WFSN) grading scale, that is 5 for 37 patients (35.3%), 4 for 28 patients. In 40% of cases the maximum sac diameter was between 7 mm and 12 mm, while in 67% of the cases the aneurysms concerned the bifurcation of the middle cerebral artery. ICH was associated in 57 cases (54.3%). As far as outcome is concerned, at 3 months, 32 patients (30.47%) had a favourable outcome, while 73 (69.52%) patients had not favourable outcome. To one year, 46 patients (43.8%) had favourable outcomes, while 59 patients (56.19%) had not favourable outcome. The mean outcomes as mean mRS are significantly less favourable in patients with ICH. Conclusion: In MCAAs patients, the presence of ICH strongly affects the outcome with a marked increase in mortality and morbidity. Surgical timing significantly influences the outcomes and ultra-early surgery should always be taken into account
Soft Infrastructure as Landscape â A Methodology for the Assessment and Improvement of the User Experience of Soft Mobility
AbstractHow could Soft Infrastructure qualify the landscape around them? This study aims to provide a methodological framework for the analysis and for the design of cycling paths as a mean to discover the landscape and its qualities. The research project used case studies from the Western United States and in particular the city of Eugene, Oregon to envision a methodology to qualify Cycling Paths in the Landscape
Effect of the dispersion of the chromophore on the optical performances of polarizers from polyethylene and 5â-thio-(3-butyl)nonyl-2,2â:5â,2â-terthiophene
A new polyethylene-compatible terthiophene chromophore, 5"-thio-(3-butyl) nonyl-2,2':5',2"-terthiophene, with melting point lower than 0degreesC was prepared and used for linear polarizers based on ultra-high-molecular-weight polyethylene (UHMWPE). Differential scanning calorimetry and scanning electron microscopy indicate that the new chromophore is dispersed uniformly in films of UHMWPE obtained by casting from solution. The films show excellent dichroic properties (dichroic ratio 30) at rather low drawing ratio (approximate to20). Moreover, qualitative agreement is observed with the Ward pseudo-affine deformation schem
Multimodal Argument Mining: A Case Study in Political Debates
We propose a study on multimodal argument mining in the domain of political debates. We collate and extend existing corpora and provide an initial empirical study on multimodal architectures, with a special emphasis on input encoding methods. Our results provide interesting indications about future directions in this important domain
Linear low density polyethylene (LLDPE) films containing perylene dyes as stress-strain luminescent indicators
Linear low density polyethylene (LLDPE) films containing different concentrations of perylene (P) chromophores have been prepared by solution-casting and compression-moulding. The light emission features of the films depend on P concentration and polymer films deformation. A well-defined band attributed to the formation of micro/ nano-structured perylene chromophoric aggregates is observed with more than 0.1 wt.% of P in the film. The occurrence of this phenomenon changed the emission colour of the films from a bright blue (non- interacting dyes) to low intense pale yellow (interacting dyes) colour. During film drawing the LLDPE macromolecules reorganization is able to break the P supramolecular organization, leading to the prevalence of the blue emission of monomeric P. The optical behaviour of perylene dyes acting as internal stress- strain luminescent indicators for polyethylene films, provides a powerful tool to detect macromolecular organization
Polymer Nanocomposites Containing Anisotropic Metal Nanostructures as Internal Strain Indicators
Polymer/metal nanocomposite containing intrinsically anisotropic metal nanostructures such as metal nanorods and nanowires appeared extremely more sensitive and responsive to mechanical stimuli than nanocomposites containing spherical nanoparticles. After uniaxial stretching of the supporting polymer matrix (poly(vinyl alcohol)), the elongated silver nanostructures embedded at low concentration into the polymer matrix (<1 wt % of Ag) assume the direction of the drawing, yielding materials with a strong dichroic response of the absorption behavior. Accordingly, the film changed its color when observed under linearly polarized light already at moderate drawings. The results obtained suggest that nanocomposite films have potential in applications such as color polarizing filters, radiation responsive polymeric objects and smart flexible films in packaging applications
Julolidine fluorescent molecular rotors as vapour sensing probes in polystyrene films
We introduce a new sensing polymer system for detection of volatile organic compounds (VOCs) based
on the optical response of polystyrene (PS) films doped with julolidine fluorescent molecular rotors
(FMRs). The julolidine FMRs exhibited viscosity-dependent changes in the fluorescence intensity, that
was enhanced when glycerol was added to ethanol solutions and when they were dispersed in PS films.
Thus, reduction in medium mobility slowed down internal motions and allowed for a major radiative
decay pathway. The FMR/PS films were exposed to several VOCs, and showed a significant decrease in
fluorescence emission when exposed to chloroform, whereas a negligible variation in their emission
occurred when methanol was utilized. This vapour sensing behaviour was much more evident when a
perfluorodecyl chain was linked to the julolidine core being the molecule segregated at the film surface.
This responsive behaviour was affected by solvent composition and its reproducible response was easily
determined by luminescence experiments
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