Reducing the Impact of Uplift Pressures on the Base of a Concrete Dam by Configuration of Drainage Holes (Hypothetical Case Study)

A study of the impact of the uplift pressures upon base of a typical water retaining structure was presented. This work was conducted through numerical analysis by finite element method to evaluate the hydraulic uplift pressure distribution generated by the calculated flow. Also, the effects of position of either single or dual drainage holes on uplift pressures characteristic were included. A hypothetical case was solved for three types of drainage holes, and the reduction of uplift pressures were computed in each case, a comparison was presented and the results showed that it can produce the desired reduction in hydraulic uplift pressures by using two drainage holes at equidistance of 8m from upstream edge of structure floor

Wa-LiD: A new LiDAR simulator for waters

A simulator (Wa-LiD) was developed to simulate the reflection of LiDAR waveforms from water across visible wavelengths. The specific features of the simulator include (i) a geometrical representation of the water surface properties, (ii) the use of laws of radiative transfer in water adjusted for wavelength and the water’s physical properties, and (iii) modelling of detection noise and signal level due to solar radiation. A set of simulated waveforms was compared with observed LiDAR waveforms acquired by the HawkEye airborne and GLAS satellite systems in the near-infra red or green wavelengths and across inland or coastal waters. Signal-to-noise ratio (SNR) distributions for the water surface and bottom waveform peaks are compared with simulated and observed waveforms. For both systems (GLAS and HawkEye), Wa-LiD simulated SNR conform to the observed SNR distributions

Reactive Powder Concrete with Steel, Glass and Polypropylene Fibers as a Repair Material

Repairing of reinforced concrete structures is currently a major challenge in the construction industry and is being put back into operation with a slight loss in load carrying capacity. Damage occurs due to many factors that reduce the strength of concrete structures and their durability. The aim of this paper is study the compatibility between three types of reactive powder concrete with (steel fibre, glass fibre and polypropylene fibre) as a repair materials and normal strength concrete as a substrate concrete. Compatibility was investigated in three steps. First: individual properties for substrate concrete were studied, these are (slump test, compressive strength, splitting strength, and flexural strength) also, for repair material these are (compressive strength and flexural strength) were determined by using standard ASTM test methods. Second: bond strength of composite cylinder for substrate concrete with different repair materials were evaluated by using slant shear test. Third: compatibility was investigated by using composite prisms of substrate concrete with different repair materials under two-point loading (flexural strength test). From the experimental results concluded, bond strength between reactive powder concrete with glass fibre as a repair material and normal strength concrete as a substrate layer is higher (17.38Mpa) compared with RPC with steel fibre (13.13Mpa) and polypropylene fibre (14.31MPa). Also, it is more compatible due to flexural strength for composite prisms (having higher flexural strength (8.13MPa). Compared with steel fibre (7.44MPa) and polypropylene fibre (6.47MPa). These results due to RPC with glass fibre have good workability with suitable flowability and glass fibre have higher tensile strength compare with other fibre

Effects of vertical loading on lateral screw pile performance

The offshore wind energy sector faces new challenges as it moves into deeper water deployment. To meet these challenges, new and efficient foundation solutions are required. One potential solution is to upscale onshore screw piles but they require verification of performance for new geometries and demanding loading regimes. This paper presents a three-dimensional finite-element analysis investigation of screw pile behaviour when subjected to combined vertical and lateral loading in sand. In the investigation, the screw pile length and helical plate diameter were varied on piles with a fixed core diameter while subjecting the piles to combined axial and lateral loading. The results were compared with results from straight shafted piles with the same core diameter. The results of the analysis revealed that vertical compression loads increased the lateral capacity of the screw piles whereas vertical uplift loads marginally reduced the lateral capacity. The downside of this enhanced lateral capacity is that the screw piles experience higher bending moments. This suggests that, when using screw piles for offshore foundation applications, structures should be designed to maintain axial compressive loads on the piles and induced bending moments need to be adequately assessed when deciding on appropriate structural sections. </jats:p

Analysis of TerraSAR-X data and their sensitivity to soil surface parameters over bare agricultural fields

International audienceCette recherche a pour objectif de mettre en évidence la contribution des capteurs haute résolution pour une meilleure caractérisation de la surface du sol et pour analyser les effets de la polarisation et de l'angle d'incidence radar. L'objectif de cet article est d'analyser la sensibilité des données haute résolution Terrassar-X sur des sols sans couverture végétale et d'étudier la variabilité spatiale. Les relations entre le coefficient de rétrodiffusion et les paramètres du sol seront étudiés grâce aux images (TerraSAR, Ikonos, SPOT) ainsi que grâce aux mesures de terrain recueillies pendant plusieurs campagnes de terrain en hiver et printemps 2008-2009. Ce travail a été mené sur le bassin de l'Orgeval (France). / Our research aims to show the contribution of high resolution spatial sensors for a better characterization of soil surface, and to analyze polarization effects and radar incidence angle. The objective of this paper is to analyze the sensitivity of very high resolution TerraSAR-X radar data taken over bare soils, and to study the spatial variability. The relationship between backscattering coefficient and soil's parameters (moisture, surface roughness, and texture) will be examined by means of satellite images (TerraSAR, Ikonos, SPOT), as well as ground truth measurements, recorded during several field campaigns in the winter and spring of 2008 and 2009. This study is carried out on Orgeval catchment (France)

On chip interconnects for multiprocessor turbo decoding architectures

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Root extracts of Saussurea costus as prospective detoxifying food additive against sodium nitrite toxicity in male rats

Financiado para publicación en acceso aberto: Universidade de Vigo/CISUGThe goal of this study was to investigate the effects of three different extracts of Saussurea costus roots (ethanol, methanol, and water) as a food additive in alleviating the harmful effect of sodium nitrite in rat meals. Thirty-five adult male rats were divided into five groups as follows: control, sodium nitrite (NaNO2; 75 mg/kg BW, single oral dose), S. costus 70% ethanol, 70% methanol, and aqueous extracts (300 mg/kg BW), respectively for four weeks followed by a single dose of NaNO2 24h before decapitation. Results showed that the 70% ethanol extract of S. costus has a higher concentration of total phenolic content, total flavonoids, and antioxidant effect than the 70% methanol and water extracts. Rats pretreated with S. costus extracts reduced the harmful effects induced by NaNO2 and improved the hematological parameters, liver, and kidney function biomarkers as well as lipid profile as compared to the NaNO2 group. Furthermore, S. costus improved the histopathological alterations in the liver and kidney induced by NaNO2 and improved meat sensory evaluation. Conclusively, the 70% ethanol extract of S. costus roots is the most effective extract as an antioxidant against the toxicity of sodium nitrite in male rats and might be used safely as a natural additive in the food industry