147 research outputs found
2d river flood modelling using Hec-ras 5.0
Flooding may occur as an overflow of water from water bodies, such as a river, lake or ocean, in
which the water overtops or breaks levees, resulting in some of that water escaping its usual
boundaries. Floods also occur in rivers when the flow rate exceeds the capacity of the river
channel.
Floods represent the deadliest natural hazard in Europe, resulting in loss of life, damage to buildings,
homes, business and structures such as bridges and roads. Since such consequences are highly
undesirable for human beings, the need to avoid or at least control them has become obvious.
This led to the appearance of hydrodynamic models, numerical tools able to simulate the flow
movement, also in case of flooding. Those models would let us know how the flow behaves in
certain situations and how to act in consequence in order to avoid those undesirable effects.
In April 2016, the new two-dimensional version of HEC-RAS has been released, the so-called
HEC-RAS 5.0. This version is especially interesting since all previous versions of HEC-RAS
had never been able to simulate flows in two dimensions. The main motivation of this document
is to analyse the functionality and workability of HEC-RAS 5.0 regarding two-dimensional
river flooding. In order to do so, three different work approaches have been carried out, with
further analysis of the correspondent results.
First, a detailed intercomparison between the main hydrodynamic models available has been
carried out in order to check the features of the new version of HEC-RAS next to another four
computational programs.
Second, the same case simulation has been performed at the same time for HEC-RAS 5.0 and
for Delft3D. The aim of this is to check the reliability and functionality of HEC-RAS new
version regarding to 2D river flood modelling next to an already developed two-dimensional
model such as Delft3D is. For this simulation, an ideal created prismatic channel has been
chosen in order to work in a basic scenario and two approaches have been analysed: steady nonflooding
and unsteady flooding cases.
Finally, and once its workability has been checked, a more complex case has been simulated
with HEC-RAS 5.0. In this case, the scenario is a real case study, consisting in a river flood in
the FluviĂ River, in Catalonia, Spain, with real data of a return period of 50 years, obtained
from Agència Catalana de l’Aigua (ACA) in 2009.
The results led to very sensitive output, realistic and similar to the expected and contrasted.
Thus, one can conclude that, despite small instabilities were found, HEC-RAS 5.0 is able to
perform simple 2D river flood modelling simulations at a similar level of the most advanced
two-dimensional programs, such as Delft3D. However, when it comes to very complex
simulations, some features, such as combination with transport of substances and water quality
or combination with sediment transport and morphological evolution, are not yet available in
two dimensions for HEC-RAS 5.0, so one would rather choose a more advanced model
Estudi sobre el transport de mercaderies per ferrocarril a Espanya: situaciĂł actual (2009) i perspectives a mig termini (2015)
L’objecte d’aquest estudi és analitzar la situació actual del transport de mercaderies per ferrocarril a Europa, en general, i a l’Estat espanyol, en concret.
Per a fer-ho, serĂ necessari descriure el marc legal corresponent resultant de les
reformes sectorials esdevingudes en els darrers anys, la planificaciĂł de les
respectives xarxes duta a terme per les administracions corresponents aixĂ com
la posició en que es troba el transport ferroviari de mercaderies en l’actualitat.
Per al cas espanyol, caldrà traçar el procés de liberalització viscut i fer una
radiografia de l’estat en que es troba a dia d’avui on hi apareguin els principals
agents del sector. AixĂ mateix, cal descriure algunes de les causes principals de
les diferències existents que responen a aspectes tècnics propis del ferrocarril.
Per últim, és objecte del present estudi proposar mesures i propostes d’actuació
que donin resposta a la problemĂ tica existent en quant a expectatives inicials
creades per la liberalitzaciĂł del transport de mercaderies per ferrocarril a Espanya aixĂ com la definiciĂł de perspectives a mig termini (horitzĂł 2015)
Xiu-Xiu, only a royal page?
Terrassa es una ciutat de tradicions de tot tipus com el jazz, l’hoquei herba, els castells, i el
patge Xiu-Xiu. D’aquest últim personatge, possiblement pel seu carà cter mà gic, se sap ben
poca cosa. Aquest Ă©s el motiu principal que em motiva per esbrinar el seu naixement, el
context històric, qui son els pares, quina motivació els va moure a fer-ho, i en la mida que ha
estat possible, aglutinar en un sol treball totes les dades disperses que existeixen.Terrassa is a city of traditions of all kinds, like jazz, field hockey, castells (human towers), and
the royal page Xiu-Xiu. Of this last character, possibly because of his magical character, we
know very little. This is the main reason that motivates me to find out his birth, the historical
context, who are the parents, what motivation moved them to do it, and to extend as much as
possible, to bring together in a single work all the scattered data that exist
Acceleració d'algoritmes de clustering mitjançant targetes grà fiques
En aquest projecte s'ha estudiat com es comporten diferents algoritmes de clustering amb diferents opotimitzacions de CUDA. Concretament s'han estudiat com funcionen l'algoritme k-means i k-centers amb les optimitzacions de Shared Memory i quan garantim els accessos coalesced
Thermal response of Sanabria lake to global change (NW Spain)
Are large water bodies able to act as sensors of global change? As accumulators of water and heat, some of their thermal characteristics might be altered by long term (decadal) hydrometeorological changes and thus may be used as indicators of the effects of global change on fluvial ecosystems. This work focuses on the effect of global change (climate change plus water quantity and land use changes) in the internal organization of Sanabria Lake, specifically in its thermal annual cycle. The existence of temporal trends in the thermal behaviour of the lake was investigated based on the water temperature profiles are available since 1986. Data analyses include the non-parametric Mann-Kendall trend test and the Sen slope estimate to evaluate long term and seasonal patterns of hydrometeorological and in-lake thermal variables. The main results surprisingly point to a net lake cooling that could be explained by a stronger thermocline and a weaker vertical transfer of heat to the hypolimnion during the stratification period. These results contribute to understand and quantify the effects of global change on Iberian freshwater bodies.Peer ReviewedPostprint (published version
Retaining or excising the supraspinatus tendon in complex proximal humeral fractures treated with reverse prosthesis: a biomechanical analysis in two different designs
Purpose:
We aimed to biomechanically evaluate the effect of the supraspinatus tendon on tuberosity stability using two different reverse shoulder arthroplasty (RSA) models for complex proximal humeral fractures (PHFs)
Methods:
Four-part proximal humeral fractures were simulated in 20 cadaveric shoulders. Two different RSA designs were implemented: a glenosphere-medialized model and a glenosphere-lateralized model. Tuberosities were reconstructed, and displacement of bony fragments was measured (mm) by placing three sensors: in the humeral diaphysis (D), in the greater tuberosity (GT), and in the lesser tuberosity (LT). Axial forces were induced and measured in Newton (N). The test was performed twice in each specimen, with and without the supraspinatus tendon. The regression line (RL) was measured in mm/N.
Results:
In the medialized model, the GT–D displacement was greater in the supraspinatus preserving model than that in the tendon excision model (p<0.001), as well as for the LT–D displacement (p<0.001). In the lateralized model, GT–D displacement and GT–LT distance were greater in the preserving model than that in the excision model (p<0.001, p=0.04).
Conclusion:
The supraspinatus tendon resection leads to a more biomechanically stable tuberosity construct when performing RSA for PHFs, while the rest of the rotator cuff tendons (infraspinatus and teres minor) are retained in the greater tuberosity.Peer ReviewedPostprint (author's final draft
Efficacy of liposomal amphotericin B and anidulafungin using an antifungal lock technique (ALT) for catheter-related Candida albicans and Candida glabrata infections in an experimental model
Liposomal amphotericin B; Antifungal lock technique; Candida albicansAmfotericina B liposomal; Tècnica de bloqueig antifúngic; Candida albicansAnfotericina B liposomal; Técnica de bloqueo antifúngico; Candida albicansOBJECTIVE:
The aims of this study were as follows. First, we sought to compare the in vitro susceptibility of liposomal amphotericin B (LAmB) and anidulafungin on Candida albicans and Candida glabrata biofilms growing on silicone discs. Second, we sought to compare the activity of LAmB versus anidulafungin for the treatment of experimental catheter-related C. albicans and C. glabrata infections with the antifungal lock technique in a rabbit model.
METHODS:
Two C. albicans and two C. glabrata clinical strains were used. The minimum biofilm eradication concentration for 90% eradication (MBEC90) values were determined after 48h of treatment with LAmB and anidulafungin. Confocal microscopy was used to visualize the morphology and viability of yeasts growing in biofilms. Central venous catheters were inserted into New Zealand rabbits, which were inoculated of each strain of C. albicans and C. glabrata. Then, catheters were treated for 48h with saline or with antifungal lock technique using either LAmB (5mg/mL) or anidulafungin (3.33mg/mL).
RESULTS:
In vitro: anidulafungin showed greater activity than LAmB against C. albicans and C. glabrata strains. For C. albicans: MBEC90 of anidulafungin versus LAmB: CA176, 0.03 vs. 128 mg/L; CA180, 0.5 vs. 64 mg/L. For C. glabrata: MBEC90 of anidulafungin versus LAmB: CG171, 0.5 vs. 64 mg/L; CG334, 2 vs. 32 mg/L. In vivo: for C. albicans species, LAmB and anidulafungin achieved significant reductions relative to growth control of log10 cfu recovered from the catheter tips (CA176: 3.6±0.3 log10 CFU, p≤0.0001; CA180: 3.8±0.1 log10 CFU, p≤0.01). For C. glabrata, anidulafungin lock therapy achieved significant reductions relative to the other treatments (CG171: 4.8 log10 CFU, p≤0.0001; CG334: 5.1 log10 CFU, p≤0.0001).
CONCLUSIONS:
For the C. albicans strains, both LAmB and anidulafungin may be promising antifungal lock technique for long-term catheter-related infections; however, anidulafungin showed significantly higher activity than LAmB against the C. glabrata strains
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