Dalimier E.,LLTech SAS |
Salomon D.,University of Monastir
Dermatology | Year: 2012
Background/Aims: Full-field optical coherence tomography (FFOCT) is a new imaging technology that can provide 3D micron-level resolution and is suited for high-resolution imaging of biological tissue. The aim of this study was to evaluate its capacity and potential for imaging human epidermis and dermis and various skin pathologies in ex vivo and in vivo conditions. Methods: Non-fixed and fixed samples of normal and pathological skin and normal in vivo skin were imaged with a FFOCT system and compared to histological slides. Results: The epidermis and adnexae, the collagen bundles of the dermis and the hypodermis could be identified through architectural and cellular details. The pathological structures were distinguished from the normal structures and corresponded to their histopathological organization. Conclusion: FFOCT is a novel technology in the field of skin imaging that has the potential to be a relevant complement to existing non-invasive imaging modalities for clinical and cosmetic applications. Copyright © 2012 S. Karger AG, Basel.
Daouas N.,University of Monastir
Applied Energy | Year: 2011
In Tunisian climate, both heating in winter and cooling in summer are required to reach comfort levels. Due to the significant increase in building energy consumption, insulation of external walls is recently applied with a thickness typically ranging between 4cm and 5cm regardless of structure and orientation of walls and of economic parameters. In the present study, optimum insulation thickness, energy saving and payback period are calculated for a typical wall structure based on both cooling and heating loads. Yearly transmission loads are rigorously estimated using an analytical method based on Complex Finite Fourier Transform (CFFT). Considering different wall orientations, the west and east facing walls are the least favourite in the cooling season, whereas the north-facing wall is the least favourite in the heating season. A life-cycle cost analysis over a building lifetime of 30years shows that the south orientation is the most economical with an optimum insulation thickness of 10.1cm, 71.33% of energy savings and a payback period of 3.29years. It is noted that wall orientation has a small effect on optimum insulation thickness, but a more significant effect on energy savings which reach a maximum value of 23.78TND/m2 in the case of east facing wall. A sensitivity analysis shows that economic parameters, such as insulation cost, energy cost, inflation and discount rates and building lifetime, have a noticeable effect on optimum insulation and energy savings. Comparison of the present study with the degree-days model is also performed. © 2010 Elsevier Ltd.
Bahloul R.,University of Monastir
Materials and Design | Year: 2011
The objective of this work is modelling and optimisation of sheet bending process by means of numerical simulation. One of the problems to be solved in the sheet metal forming processes of thin sheets is the taking into account of the effects of technological process parameters so that the part takes the desired mechanical characteristics. Accordingly, it has been a crucial research subject for designing bending tools guaranteeing an optimal performance of products in terms of mechanical properties and good rigidity. In this paper, we propose a numerical procedure allowing the definition of the optimal values of process parameters in flanging operation, which minimises the residual stresses and the material damage at the end of the bending phase. The concept of continuum damage mechanics fully coupled with elasto-plasticity has been retained to describe the progressive damage accumulation into the sheet metal. According to parametric investigation on the maximum stress and calculated damage values, it has been found that the punch-die clearance and the die radius have significant effects on mechanical behaviour of parts. An application of design of experiments was developed as a preliminary step for the optimisation of the process parameters by using response surface methodology. This model allows the identification of the influential parameters of an optimisation problem and the reduction of the number of evaluations of the objective function. © 2010 Elsevier Ltd.
Mnif W.,University of Monastir
Archives of environmental contamination and toxicology | Year: 2010
Endocrin-disrupting compounds (EDCs) are frequently found in wastewater treatment plants (WWTPs). So far, research has been mainly focused on the detection of estrogenic compounds and very little work has been carried out on other receptors activators. In this study, we used reporter cell lines, which allow detecting the activity of estrogen (ERalpha), androgen (AR), pregnane X (PXR), glucocorticoid (GR), progesterone (PR), mineralocorticoid (MR), and aryl hydrocarbon (AhR) receptors, to characterise the endocrine-disrupting profile of the aqueous, suspended particulate matter, and sludge fractions from three Tunisian WWTPs. The aqueous fraction exhibited estrogenic and androgenic activities. Suspended particulate matter and sludge extracts showed estrogenic, aryl hydrocarbon and pregnane X receptor activities. No GR, MR, or PR (ant) agonistic activity was detected in the samples, suggesting that environmental compounds present in sewage might have a limited spectrum of activity. By performing competition experiments with recombinant ERalpha, we demonstrated that the estrogenic activity detected in the aqueous fraction was due to EDCs with a strong affinity for ERalpha. Conversely, in the sludge fraction, it was linked to the presence of EDCs with weak affinity. Moreover, by using different incubation times, we determined that the EDCs present in suspended particulate matter and sludge, which can activate AhR, are metabolically labile compounds. Finally, we showed in this study that environmental compounds are mainly ER, AR, PXR, and AhR activators. Concerning AR and PXR ligands, we do not to know the nature of the molecules. Concerning ER and AhR compounds, competition experiments with recombinant receptor and analysis at different times of exposure of the AhR activation gave some indications of the compound's nature that need to be confirmed by chemical analysis.
Chatti S.,University of Monastir
Computers and Structures | Year: 2010
Commonly finite element analysis uses hypoelastoplastic (HEP) formulation to simulate forming processes and springback. In this study an elastoplastic (EP) formulation in finite strains is used. In the case of large elastic domain it has been found that the HEP law leads to oscillatory responses in shear test. Furthermore we show that the use of this law in springback simulation needs many increments to obtain an accurate solution. Alternatively, the use of an EP law gives a non-oscillatory solution in shear test and it needs a few numbers of increments in springback simulations to obtain accurate results. © 2010 Elsevier Ltd. All rights reserved.
Omri A.,University of Monastir
Renewable and Sustainable Energy Reviews | Year: 2014
In this paper, an extensive review of the rapidly growing in the literature on the nexus between economic growth and four types of energy consumption: total energy consumption, electricity consumption, nuclear consumption, and renewable consumption. The various hypotheses associated with the causal interaction between these variables along with a survey of the empirical literature are also discussed. The survey focuses on country coverage, periods, modeling techniques, and empirical conclusions. A general observation from these studies that results are found to be sensitive to methodology and type of energy considered. The empirical results for the specific countries surveyed show that (i) for energy consumption-growth nexus: 29% supported the growth hypothesis, 27% the feedback hypothesis, 23% the conservation hypothesis, and 21% the neutrality hypothesis; (ii) for the electricity consumption-growth nexus: 40% supported the growth hypothesis, 33% the feedback hypothesis, and 27% conservation hypothesis; (iii) for the nuclear consumption-growth nexus: 60% supported the neutrality hypothesis, and 40% the growth hypothesis; and (iv) for the renewable consumption-growth nexus: 40% supported the neutrality hypothesis, 40% the conservation hypothesis, and 20% the growth hypothesis. These mixed results may be attributed to the different used data, selected variables, and econometric approaches undertaken. © 2014 Elsevier Ltd.
La Scola B.,University of Monastir
Expert Review of Molecular Diagnostics | Year: 2011
MALDI-TOF mass spectrometry (MS) on intact cells is at the forefront of a new revolution in the routine identification of microorganisms in clinical microbiology laboratories. In addition to its high accuracy for identification, it provides results in just a few minutes. As correct and timely diagnoses are pivotal for the management of bloodstream infections, MALDI-TOF MS has the potential to replace or at least complement other methods for microorganism identification in bloodstream infections. With the improvement of databases and software, this method has an accurate identification rate of nearly 100% on nearly all agar-grown microorganisms and more than 80% on positive blood culture broth tests. Even if it is highly efficient now, after a decade of developments, the technique is currently still under improvement. It lacks standardization and exhaustive databases or more efficient softwares that are currently under development. Even now, both the technology itself and the reagents are improving significantly. Thus, it is likely that identifications will become more accurate in the future, especially on more complex fluids, such as blood culture broth. © 2011 Expert Reviews Ltd.
Chastel C.,University of Monastir
Frontiers in Physiology | Year: 2012
In dengue virus infections the asymptomatic cases are much more frequent than the symptomatic ones, but their true role in the introduction and subsequent spread of dengue viruses in non-endemic regions remains to de clarified. We analyzed data from English and French literatures to assess if viremia in asymptomatic dengue infections might be sufficient to represent a true risk. During outbreaks of dengue a large number of individuals are infected and since viremia levels in symptomatic patients are known to vary by many orders of magnitude, it is reasonable to augur that a proportion of asymptomatic cases might reach levels of viremia sufficient to infect competent mosquitoes. In addition, a number of newways of contamination in man by dengue viruses were recently described such as blood transfusion, bone marrow transplantation, and nosocomial infections that may be worth considering. © 2012 Chastel.
Belgacem B.G.,University of Monastir
Energy for Sustainable Development | Year: 2012
Water pumping system is one of the most economically viable photovoltaic applications in remote areas especially in developing countries. For the favorable solar radiation conditions in Tunisia (3000h of solar radiation per year) and an average daily solar radiation intensity exceeding 6kWh/m 2/day, solar water pumping for domestic use, for irrigation and cattle watering can be critically important, and the value of a PV water pumping system in these circumstances can far exceed its costs. Four NE 42-30 Pleuger submersible pumps were installed at four different locations in the region of Kairouan (36.5° N, 10.11° E), 150. km south of Tunis. Three of these pumps were supplied by 2.1. kWp AEG PV modules, while the fourth was supplied by 2.8. kWp AEG PV modules. Prior to its installation, the subsystem (inverter, motor and pump) had been tested with a linear source in accordance with frequency and head. The subsystem starts when its output frequency and voltage achieve 35. Hz and about 60% of the nominal voltage of the asynchronous motor. As illustrated in this work, performance tests (with linear source) and performance tests (with PV source) carried out while operating the system under local climatic conditions are well matched. At constant head pumping, the maximum overall efficiency of the system is 3.7% and the mean efficiency over this period is 2.5%. © 2012 International Energy Initiative.
STMicroelectronics and University of Monastir | Date: 2012-04-18
A deserializer circuit includes demultiplexer circuitry configured to receive serial data from an input and output a plurality of divided data outputs, and multiplexer circuitry configured to receive a first logic level at a first input of said multiplexer circuitry, and receive a second logic level at a second input of said multiplexer circuitry and receive one of said divided data outputs at a control input of said multiplexer circuitry. The outputs of the multiplexer circuitry produce the received serial data in a parallel form.