Low fouling conditions in dead-end filtration: Evidence for a critical filtered volume and interpretation using critical osmotic pressure

This paper presents experiments showing the existence of a critical filtered volume (CFV) when operating colloid dead-end filtration. The CFV is here defined as the filtered volume below which there is no irreversible (with respect to a break in the filtration) fouling on the membrane surface: it has thus the same meaning as cross-flow critical flux but applied to a dead-end process. The existence of the CFV is demonstrated when filtering stable latex or clay suspensions in constant-flux filtration experiments with alternating rinses: in contradiction to the current view, an irreversible deposit is not formed as soon as dead-end filtration begins. This critical filtered volume is shown to be dependent on the suspension stability and to be fully linked to the permeate flux: for permeate fluxes of 80 and 110 l h−1 m−2 the CFV is, respectively, 82 and 65 l m−2 for latex particles. Analyses of results are made by depicting the transition between concentration polarisation and deposit formation considering a critical osmotic pressure, which appears to be a characteristic of the fouling potential of a suspension. The results are discussed in the light of how this concept could lead to an interesting way to control and develop a strategy to operate filtration in dead-end mode

Fourier Expansion of the Riemann zeta function and applications

We study the distribution of values of the Riemann zeta function $\zeta(s)$ on vertical lines $\Re s + i \mathbb{R}$, by using the theory of Hilbert space. We show among other things, that, $\zeta(s)$ has a Fourier expansion in the half-plane $\Re s \geq 1/2$ and its Fourier coefficients are the binomial transform involving the Stieltjes constants. As an application, we show explicit computation of the Poisson integral associated with the logarithm of $\zeta(s) - s/(s-1)$. Moreover, we discuss our results with respect to the Riemann and Lindel\"{o}f hypotheses on the growth of the Fourier coefficients.Comment: 21 page

Self-Partial and Dynamic Reconfiguration Implementation for AES using FPGA

This paper addresses efficient hardware/software implementation approaches for the AES (Advanced Encryption Standard) algorithm and describes the design and performance testing algorithm for embedded system. Also, with the spread of reconfigurable hardware such as FPGAs (Field Programmable Gate Array) embedded cryptographic hardware became cost-effective. Nevertheless, it is worthy to note that nowadays, even hardwired cryptographic algorithms are not so safe. From another side, the self-reconfiguring platform is reported that enables an FPGA to dynamically reconfigure itself under the control of an embedded microprocessor. Hardware acceleration significantly increases the performance of embedded systems built on programmable logic. Allowing a FPGA-based MicroBlaze processor to self-select the coprocessors uses can help reduce area requirements and increase a system's versatility. The architecture proposed in this paper is an optimal hardware implementation algorithm and takes dynamic partially reconfigurable of FPGA. This implementation is good solution to preserve confidentiality and accessibility to the information in the numeric communication

Local mechanical properties of bladder cancer cells measured by AFM as a signature of metastatic potential

International audienceThe rheological properties of bladder cancer cells of different invasivities have been investigated using a microrheological technique well adapted in the range [1 - 300 Hz] of interest to understand local changes in the cytoskeleton microstructure, in particular actin fibres. Drugs disrupting actin and actomyosin functions were used to study the resistance of such cancer cells. Results on a variety of cell lines were fitted with a model revealing the importance of two parameters, the elastic shear plateau modulus GN0 as well as the glassy transition frequency f_T. These parameters are good markers for invasiveness, with the notable exception of the cell periphery, which is stiffer for less invasive cells, and could be of importance in cancer metastasis

Effect of inoculation by Moroccan rock phosphate solubilizing rhizobia, Versus phosphorus fertilization, on the growth and the phosphorus uptake by Vicia faba

Low Phosphorus availability in soil is worldwide a frequent major constraint for crops. Rhizobial strains, beneficial N2-fixing symbiotic partners of legumes, were reported to solubilize both organic and inorganic complex phosphates. Thus they may play a significant role as plant growth-promoting rhizobacteria (PGPR) in the biofertilization of crops. Natural rock phosphate may play a key role in sustainable agriculture, resulting in economic and environmental benefits. This work aims to evidence the capacity of rhizobial strains nodulating Vicia faba L. plants in Marrakech-Haouz region (Morocco) to solubilize Moroccan rock phosphate in vitro in either agar or liquid medium and to evaluate and compare the effect of these strains on growth and phosphorus uptake by V. faba plants of two Moroccan varieties (Defes and Aguadulce). Four rhizobial strains, contrasting for phosphate solubilization on agar medium, were further studied on liquid medium. RHOF147 and RHOF174 strains formed clear halos around colonies (1.37 cm and 1.2 respectively after 15 days); opposite RHOF170 and RHOF171 strains did not produce halo. The four strains were able to mobilize rock phosphate for growth in liquid medium (up to 0.59 mg/L of assimilated phosphorus). Lower pH values and most mobilized phosphorus production were registered for RHOF147 and RHOF174 strains. By screening the four rhizobial strains for growth on Chrome Azurol S (CAS) medium, only RHOF171 strain formed orange halo indicating its capacity to produce siderophores. Greenhouse experiments were undertaken including comparison of inoculated plants with these four rhizobial strains in the presence of rock phosphate as sole P source versus non-inoculated plants growing on KH2PO4 as sole P source (P-fertilized plants). Results show that the root length, the root dry weight and the ratio root /shoot dry weights were generally higher in the inoculated plants than in the P-fertilized plants, indicating the adaptation of the inoculated plants to phosphorus deficiency conditions. The effect of rock phosphate-solubilizing bacteria on plant growth depends on the symbiotic combination of the inoculated strain and the plant genotype. As for phosphorus uptake, rhizobial strains made phosphorus available to the plant at significant increased concentrations in some symbiotic combinations (e.g. Aguadulce-RHOF147). The use of selected symbiotic combinations having the capacity to solubilize rock phosphate may improve soil fertility and phosphorus availability to plants. (Résumé d'auteur

L’amnistie fiscale sous le prisme de la théorie de l’apparence en droit commercial : enjeux de l’absence de preuve formelle.

Résumé L’apparence désigne ce qui est visible, directement accessible aux sens, et à la fois trompeur. Articuler les deux sens permet de construire une théorie générale de l’apparence. Cette théorie est au cœur des règles juridiques de fond. En droit commercial, elle permet de protéger les tiers de bonne foi lorsqu’ils se fondent sur une apparence légitime, même en l’absence de preuves formelles telles qu’un acte ou un titre. Dans le contexte marocain actuel marqué par l’amnistie fiscale, ce mécanisme se heurte fréquemment à des lacunes documentaires : absence de justificatifs formels, irrégularités dans les transactions passées, pratiques illégales. Cette absence de preuves formelles engendre une problématique centrale liée à la capacité de la théorie de l’apparence à pallier ce manque dans le processus de la régularisation fiscale. Cette réflexion nous conduit à envisager une analyse rigoureuse des conditions de mobilisation de ce principe afin d’assurer une transparence commerciale et sociale de la sphère économique au Maroc.   Mots Clés : Apparence, Spéculation Abusive, Sécurisation, Stabilité Financière, Confiance Économique.    Résumé L’apparence désigne ce qui est visible, directement accessible aux sens, et à la fois trompeur. Articuler les deux sens permet de construire une théorie générale de l’apparence. Cette théorie est au cœur des règles juridiques de fond. En droit commercial, elle permet de protéger les tiers de bonne foi lorsqu’ils se fondent sur une apparence légitime, même en l’absence de preuves formelles telles qu’un acte ou un titre. Dans le contexte marocain actuel marqué par l’amnistie fiscale, ce mécanisme se heurte fréquemment à des lacunes documentaires : absence de justificatifs formels, irrégularités dans les transactions passées, pratiques illégales. Cette absence de preuves formelles engendre une problématique centrale liée à la capacité de la théorie de l’apparence à pallier ce manque dans le processus de la régularisation fiscale. Cette réflexion nous conduit à envisager une analyse rigoureuse des conditions de mobilisation de ce principe afin d’assurer une transparence commerciale et sociale de la sphère économique au Maroc.   Mots Clés : Apparence, Spéculation Abusive, Sécurisation, Stabilité Financière, Confiance Économique.   &nbsp

Mechanical Behavior of High-Performance Concrete under Thermal Effect

Several studies on the behavior of concrete at high temperatures are the subject of recent concerns, following the latest fires in various European tunnels. In these extreme conditions, significant degradations of concrete structures can be observed (peeling, cracking, breaking of the structure). A priori prediction of concrete behavior during this type of stress is therefore essential and is not possible without a good understanding of the different mechanisms of concrete damage at high temperatures. These mechanisms are often considered as the main causes of cracking and peeling of concrete subjected to high temperatures. Therefore, a fire can strongly modify the behavior of concrete and jeopardize the stability of concrete. In case of fires, it is necessary to know the instantaneous and residual behavior of concrete subjected to temperatures up to 1000°C. In this work we present a study of the mechanical performance of high-temperature high-performance concrete (HPC) exposed to four maximum temperatures, 200, 400, 600, and 900°C. The results obtained show that the mechanical strength at 28 days increases with the degree of temperature compared with that measured at 20°C. On the contrary, a clear decrease is observed between 600 and 900°C