Maximum Moduli of Sands Under Various Loadings

Maximum moduli are the primary parameter in the determination of wave velocities in soils. They can be evaluated from either laboratory or field testing. In general, the excitation loadings used in laboratory and field testing are different. The resonant column apparatus was used to study the effect of loading type on the maximum moduli of sands. Sinusoidal, random and impulse loading were used. Sand specimens were tested either longitudinally or torsionally with one of the three types of loading at low strain levels, and the low-amplitude moduli were measured. Maximum moduli of the specimens were obtained from the low-amplitude moduli. It was concluded that loading type has no effect on the maximum moduli of soils. Also, the maximum moduli at different confining pressures agreed well with published equations

Dynamic Youngis Modulus and Axial Strain Relationships

Equations of Young’s moduli of sands as a function of the axial strain amplitude for different types of dynamic loading were developed from a series of resonant column tests. Ottawa 20-30 sand specimens were excited longitudinally with one of three types of loading at three different confining pressures. In the sinusoidal tests, excitation signals were generated by a variable frequency sine-wave oscillator. In the random tests, input signals were generated by a white-noise generator and a pulse signal generator was used in the impulse tests. Input and output signals were analyzed by an FFT analyzer in the random and impulse loading tests. Under each type of loading it was found that the Young’s modulus normalized with the initial maximum Young’s modulus for the different confining pressures could be unified using a normalized axial strain with a reference axial strain for each loading type. Relationships that determine the variation of the Young’s modulus with the axial strain were developed for each type of loading

Combination of theoretical analysis and FTIR to study the photocurrent oscillation of Silicon in fluoride media

To deepening our knowledge of the behaviour of the silicon/electrolyte interface, a study of photocurrent oscillations on silicon in fluoride concentration c F =0.033 M is realized, and as a confirmation of the result the investigation is extrapolated to a variety of electrolyte compositions. The etch rates of anodic oxides in diluted fluoride solutions have been determined by using a new approach of the analysis of anodic current oscillations. The time dependent thickness of the anodic oxide has been measured by in-situ FTIR and can be simulated considering only the time dependent current and the etch rate.To deepening our knowledge of the behaviour of the silicon/electrolyte interface, a study of photocurrent oscillations on silicon in fluoride concentration c F =0.033 M is realized, and as a confirmation of the result the investigation is extrapolated to a variety of electrolyte compositions. The etch rates of anodic oxides in diluted fluoride solutions have been determined by using a new approach of the analysis of anodic current oscillations. The time dependent thickness of the anodic oxide has been measured by in-situ FTIR and can be simulated considering only the time dependent current and the etch rate

Fast Fashion Assessment Tool: A Case Study of a Moroccan Apparel Supply Chain

In order to increase their profit margins and international expansion, many international fashion brands implemented a new supply chain strategy named fast fashion. It is a strategy that aims to rapidly get the trendiest fashion clothes in the stores. Several Moroccan fashion retailers tried to copy the fast fashion business model in order to get a responsive supply chain and a high profit margin. Thus, they need a practical tool to ensure that the fast fashion elements are properly implemented. This paper develops an assessment tool using a maturity evaluation model. This maturity assessment tool has been tested at a Moroccan fast fashion retailer. This pilot test adopted a qualitative research methodology with data collected using semi-structured interviews from a single retailer case operating in Moroccan apparel industry. The fast fashion assessment tool enables fashion retailers managers to have a view of the implementation progression and to eventually locate problems and mobilise other tools and mechanisms to explore them

Nonparametric Bayesian-based recognition of solar irradiance conditions: Application to the generation of high temporal resolution synthetic solar irradiance data

International audienc

Adverse Effects of Condenser Cooling Seawater Temperature, Fouling, and Salinity on the Output Power and Thermal Efficiency of BWR NNPs

Increasing the thermal efficiency in newly designed power stations is a priority. Keeping the efficiency in existed plants close to the rated one is of paramount importance. This research contributes to investigating the adverse effects of changes in condenser seawater coolant characteristics, (temperature, fouling, and salinity), on the thermal performance of a Boiling Water Reactor Nuclear Power Plant (BWR) NPP. A mathematical model is developed to relate seawater cooling temperature, fouling, and salinity to output power and thermal efficiency. The model also explains the impact of the condenser performance on power and efficiency. The thermal efficiency of the considered BWR NPP is reduced by 2.26% for a combined extreme increases in the condenser cooling seawater temperature, fouling factor of seawater and treated boiler feed water, and salinity by 10 °C, 0.0002, 0.00001 m2K/W, and 100 g/kg, respectively. A rise in the condenser efficiency from 40 - 100 % results in an increase in the output power by 7.049%, and the thermal efficiency increases by about 2.62%. Conclusions are useful for reactor’s desig

Preparation And Characterisation Of Zno Thin Films Deposited By SILAR Method

Zinc oxide (ZnO) thin films were grown on glass and copper substrates by the Successive Ionic Layer Adsorption and Reaction (SILAR) technique. ZnO films are obtained by successive immersion of a substrate in an aqueous solution containing: ZnSO4 with different molarities, 6ml/100ml 13.15 M aqueous ammonia solution and in deionised water heated at different temperatures. We studied the structural, morphological and optical properties with the deposition parameters (pH, bath temperature, number of cycles…) The structural, morphological surface and optical properties of the films have been studied by using X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV-VIS-spectrophotometer. Effects of experimental parameters and heat treatment on the structural and optical properties were discussed. The X-ray diffraction analysis shows that the films are polycrystalline with zincite hexagonal structure with the preferential orientation of (002) plan. The study of surface morphology reveals that deposited ZnO films take many shapes: nanorods, nanoprisms, flower-like, needles, spindles and hexagonal structures. Obtained ZnO films exhibit a high transmittance of 90% in visible band, and optical band gap of 3.27 eV.Zinc oxide (ZnO) thin films were grown on glass and copper substrates by the Successive Ionic Layer Adsorption and Reaction (SILAR) technique. ZnO films are obtained by successive immersion of a substrate in an aqueous solution containing: ZnSO4 with different molarities, 6ml/100ml 13.15 M aqueous ammonia solution and in deionised water heated at different temperatures. We studied the structural, morphological and optical properties with the deposition parameters (pH, bath temperature, number of cycles…) The structural, morphological surface and optical properties of the films have been studied by using X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV-VIS-spectrophotometer. Effects of experimental parameters and heat treatment on the structural and optical properties were discussed. The X-ray diffraction analysis shows that the films are polycrystalline with zincite hexagonal structure with the preferential orientation of (002) plan. The study of surface morphology reveals that deposited ZnO films take many shapes: nanorods, nanoprisms, flower-like, needles, spindles and hexagonal structures. Obtained ZnO films exhibit a high transmittance of 90% in visible band, and optical band gap of 3.27 eV

Antidepressants are cytotoxic to rat primary blood brain barrier endothelial cells at high therapeutic concentrations

Antidepressants are commonly employed for the treatment of major depressive disorders and other psychiatric conditions. We investigated the relatively acute cytotoxic effects of three commonly prescribed antidepressants: fluoxetine, sertraline, and clomipramine on rat primary blood brain barrier endothelial cells over a concentration range of 0.1–100 μM. At therapeutic concentrations (0.1 μM) no significant cytotoxicity was observed after 4, 24, or 48 h. At high therapeutic to overdose concentrations (1–100 μM), antidepressants reduced cell viability in proportion to their concentration and exposure duration. At 1 μM, antidepressants significantly reduced mitochondrial membrane potential. At drug concentrations producing ~ 50% inhibition of cell viability, all drugs significantly reduced cellular oxygen consumption rates, activities of mitochondrial complexes I and III, and triggered a significant increase of lactate production. Fluoxetine (6.5 μM) and clomipramine (5.5 μM) also significantly lowered transcellular transport of albumin. The mechanism of cellular cytotoxicity was evaluated and at high concentrations all drugs significantly increased the production of reactive oxygen species, and significantly increased the activity of the pro-apoptotic caspases-3, 8, and 9. Comet assays revealed that all drugs were genotoxic. Pre-incubation of cells with glutathione significantly ameliorated antidepressant-induced cytotoxicity, indicating the potential benefit of treatment of overdosed patients with antioxidants

The role of oxidative stress in antipsychotics induced ovarian toxicity

This study tested the hypothesis that oxidative stress could be an underlying mechanism for APs-induced ovarian cytotoxicity and reproductive dysfunction. Rat ovarian theca interstitial cells (TICs) were isolated and treated with four APs [chlorpromazine (CPZ), haloperidol (HAL), risperidone (RIS) and clozapine (CLZ)]. MTT assay was used to test the effects of these antipsychotics on TICs viability and to estimate their 50% inhibitory concentrations (IC50s). The effects of APs (IC50s and 1 μM concentrations) on the activities of caspases-3, -8 and -9, reactive oxygen species (ROS) production, total intracellular glutathione and lipid peroxidation (LPO) in TICs were assessed. The effect of antioxidants (reduced glutathione (GSH) and quercetin) on the APs-induced cytotoxicity on TICs was investigated. MTT assay showed all APs to reduce TICs viability. CPZ, HAL and CLZ significantly increased the activity of caspases-3, -8 and -9 (P < 0.0001, < 0.0001 and < 0.01, respectively). All APs at IC50s significantly (P < 0.0001) increased ROS production, decreased total intracellular glutathione and increased LPO. MTT assay in the presence of antioxidants (reduced GSH (5 mM) or quercetin (50 mM)) showed each antioxidant to significantly inhibit the effects of APs at their IC50s on TICs viability. In conclusion, oxidative stress seems to be a possible mechanism for APs-induced ovarian and reproductive toxicity