4,662 research outputs found
Analysis of thermal field within an urban canyon with variable thermophysical characteristics of the building's walls.
In a typical urban configuration, a microclimatic analysis has been carried out. Using a CFD method, a N-S oriented urban street canyon, with a given H/W ratio, has been examined. The standard kâΔ turbulence model has been used to simulate a three-dimensional flow field and to calculate the thermo-fluid dynamics parameters that characterize the street canyon. In this study has been analyzed the thermal flow field when the walls of the building change the properties of solar radiation absorption, in particular for α=0.2 and α=0.8. Solar radiation considered is that of 21/07 in Milan in two different hours: at 11:00 a.m. and at 02:00 p.m. The study shows the importance of the thermophysical properties of a wall, in the development of the thermal field and flow field. This is a very important topic, in terms of improvement of well-being and the quality of the air within the cities, through the choice of materials and colors of the facades of buildings.
The GIS Architecture Elements for the Coastal Areas Along the Adriatic Sea
The study of the national and cross-border Adriatic coastal areas will be approached by using an interdisciplinary method. A comparative reading will focus on an analysis of the main variations undergone by the area and will try to define all the elements involved in those areas where a conflicting presence exists between high quality environmental factors on the one hand and anthropological aggression on the other. In this paper we present the aim of the GES.S.TER. project, that is the creation of a protocol for territorial analysis â namely the G.I.S.A.E. Adriatic (Geographical Information System for Activities along the Coast). The Project is financed by the Interreg IIIA Programme Adriatic Cross Border from 2004 to 2007 (prof. Donatella Cialdea is the Head of GESS.S.TER.). Moreover the Project will be a case-study analysed by the GISIG - Geographical Information Systems International Group. The areas covered by the project include the national Adriatic coast, in particular the coastal area of Molise, and the cross-border coasts of Albania and Croatia (both partners in the project). In the definition of the characteristics that a territorial information system of aid to the GES.S.TER project should have, the parameters for the collection of data and for the reordering of the information, which was already in our possession, have been established. Another necessary step has been that of revising and coordinating the existing sources, keeping in mind that the final purpose of the system is to define the objective landscape qualities, we find ourselves having to face the problem of combining, and consequently, comparing, information coming from different sources. Five resource systems have been selected: physical-environmental; landscape-visual; historical-cultural; agricultural-productive; Demographic-tourism. A further source of information comes from the analysis carried out during the drawing up of the Vast Area Environmental Landscape Territorial Plans and we have defined the criteria for the selection of the indicators. These indicators will be useful for an evaluation of transformations through time of the territories, in order to prepare the documents for the strategic environmental assessment procedures too.
electro mechanical endurance tests on smart fabrics under controlled axial and friction forces
Abstract The design, building and validation of machine for endurance tests on fabrics are described in this paper. The system is addressed to the reliability testing of smart fabrics with electrical conductivity. The development of e-textiles, in fact, requires innovative test benches for the evaluation of performances decay with load cycles accumulation; the proposed system is able to monitor the electro-mechanical parameters of fabric sample in the same time in order to support industrial development and predict failures on final applications
Braid Groups on Triangulated Surfaces and Singular Homology
Let denote the closed orientable surface of genus and fix an
arbitrary simplicial triangulation of . We construct and study a
natural surjective group homomorphism from the surface braid group on
strands on to the first singular homology group of with
integral coefficients. In particular, we show that the kernel of this
homomorphism is generated by canonical braids which arise from the
triangulation of . This provides a simple description of natural
subgroups of surface braid groups which are closely tied to the homology groups
of the surfaces
Obesity and kidney stone disease. A systematic review
INTRODUCTION: Currently, abdominal obesity has reached an epidemic stage and obesity represents an important challenge for worldwide health authorities. Epidemiologic studies have demonstrated that the stone risk incidence increases with Body Mass Index, through multiple pathways. Metabolic syndrome and diabetes are associated with an increased renal stones disease incidence. The aim of this systematic review was to investigate the prevalence, morbidity, risk factors involved in the association between obesity and urolithiasis.
EVIDENCE ACQUISITION: The search involved finding relevant studies from MEDLINE, EMBASE, Ovid, the Cochrane Central Register of Controlled Trials, CINAHL, Google Scholar, and individual urological journals between January 2001 and May 2017. The inclusion criteria were for studies written in the English language, reporting on the association between obesity and urinary stones.
EVIDENCE SYNTHESIS: The underlying pathophysiology of stone formation in obese patients is thought to be related to insulin resistance, dietary factors, and a lithogenic urinary profile. Uric acid stones and calcium oxalate stones are observed frequently in these patients. Insulin resistance is thought to alter the renal acid-base metabolism, resulting in a lower urine pH, and increasing the risk of uric acid stone disease. Obesity is also associated with excess nutritional intake of lithogenic substances and with an increase in urinary tract infection incidence. Recent studies highlighted that renal stone disease increases the risk of myocardial infarction, progression of chronic kidney disease, and diabetes. Contemporary, bariatric surgery has been shown to be associated with hyperoxaluria and oxalate nephropathy. Certainly, the many health risks of obesity, including nephrolithiasis, will add more burden on urologists and nephrologists.
CONCLUSIONS: Obesity related nephrolithiasis seems to necessitate weight loss as primary treatment, but the recognition of the associated complications is necessary to prevent induction of new and equally severe medical problems. The optimal approach to obesity control that minimizes stone risk needs to be determined in order to manage obesity-induced renal stones disease
Complex frequency band structure of periodic thermo-diffusive materials by Floquet-Bloch theory
This work deals with the micromechanical study of periodic thermo-diffusive
elastic multi-layered materials, which are of interest for the fabrication of
solid oxide fuel cells (SOFCs). The focus is on the dynamic regime, that is
investigating the dispersive wave propagation within the periodic material. In
this framework, a generalization of the Floquet-Bloch theory is adopted, able
to determine the complex band structure of such materials. The infinite
algebraic linear system, obtained by exploiting both bilateral Laplace
transform and Fourier transform, is replaced by its finite counterpart,
resulting from a proper truncation at a finite number of considered equations.
A regularization technique is herein useful to get rid of the Gibbs phenomenon.
The solution of the problem is, finally, found in terms of complex angular
frequencies, corresponding to a finite sequence of eigenvalue problems for
given values of the wave vector. The paper is complemented by numerical
examples taking into account thermo-mechanical coupling. The overall behaviour
is found to be strongly influenced by the interaction between thermal and
mechanical phenomena
Effect of melatonin administration prior to calving on milk secretion in the next lactation in dairy cows
This study evaluated the effects of
melatonin administration 60 days prior to
expect calving (drying-off period) on milk yield
during the next lactation. Sixty dairy cows were
treated with subcutaneous melatonin implants
during summer (n=30) or winter (n=30) period.
Another 60 animals were not treated and
served as the control. There were no differences
in the average milk yield between treated and
untreated animals (44.5±3.7 and 44.8±5.0 kg/day
for melatonin and control cows, respectively).
There was an effect of season with a higher
winter milk yield than in summer (43.8±5.0
and 47.1±3.0 kg/day for melatonin and control
groups, respectively). The interaction between
melatonin and season showed no significant
effect; however, during winter, milk yield
tended to be higher (P=0.06) in control cows
than in melatonin treated cows (45.3±3.7 and
49.2±3.0, respectively). This study indicates that
treatment with melatonin prior to calving did
not modify milk yield during the following
lactation. Only a tendency for a reduction
in milk yield during winter was observed in
melatonin treated cows
Extended endoscopic endonasal transsphenoidal approach to the suprasellar area: Anatomic considerations - Part I
INTRODUCTION: Interest in using the extended endonasal transsphenoidal approach for management of suprasellar lesions, with either a microscopic or endoscopic technique, has increased in recent years. The most relevant benefit is that this median approach permits the exposure and removal of suprasellar lesions without the need for brain retraction. MATERIALS AND METHODS: Fifteen human cadaver heads were dissected to evaluate the surgical key steps and the advantages and limitations of the extended endoscopic endonasal transplanum sphenoidale approach. We compared this with the transcranial microsurgical view of the suprasellar area as explored using the bilateral subfrontal microsurgical approach, and with the anatomy of the same region as obtained through the endoscopic endonasal route. RESULTS: Some anatomic conditions can prevent or hinder use of the extended endonasal approach. These include a low level of sphenoid sinus pneumatization, a small sella size with small distance between the internal carotid arteries, a wide intercavernous sinus, and a thick tuberculum sellae. Compared with the subfrontal transcranial approach, the endoscopic endonasal approach offers advantages to visualizing the subchiasmatic, retrosellar, and third ventricle areas. CONCLUSION: The endoscopic endonasal transplanum sphenoidale technique is a straight, median approach to the midline areas around the sella that provides a multiangled, close-up view of all relevant neurovascular structures. Although a lack of adequate instrumentation makes it impossible to manage all structures that are visible with the endoscope, in selected cases, the extended endoscopic endonasal approach can be considered part of the armamentarium for surgical treatment of the suprasellar area
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