Inhibition de la corrosion d'un acier au carbone par le Kemazur 1620

Dans cette étude, des mesures électrochimiques ont été utilisées pour caractériser l'efficacité inhibitrice du produit commercial Kemazur 1620, employé pour le traitement des eaux des circuits de refroidissement. L'influence de la concentration de ce composé ainsi que l'effet de la température du milieu ont été étudiés.Les courbes de polarisation ont été obtenues à l'aide d'un montage à trois électrodes. La méthode électrochimique a permis de déterminer la vitesse de corrosion en l'absence et en présence d'inhibiteur et par conséquent, le taux de protection. Ainsi, le Kemazur 1620 présente une très bonne efficacité pour une concentration de 2000 ppm. Entre 1000 et 2000 ppm, l'efficacité inhibitrice augmente de 56 à 91 %. En outre, l'efficacité inhibitrice du composé a été comparée à celle du nitrite de sodium.In this study, electrochemical measurements were carried out to characterize the inhibition efficiency of the commercial product Kemazur 1620, employed for water treatment in cooling circuits. The influence of parameters such as the concentration of the compound and the effect of the temperature on the behavior of the carbon steel / corrosion medium interface was studied. Polarization curves have been obtained by a three-electrode device. In the first part of this study, only the evolution of the corrosion rate as a function of concentration was examined. It has been shown from the polarization curves that the Kemazur 1620 presents a very good efficiency for a concentration of 2000 ppm. Between 1000 and 2000 ppm, the inhibition efficiency increases from 56 to 91 %. In a second part, the inhibition efficiency of the compound has been compared to an inhibitor used for similar uses

Expanding the Bandwidth of Rectangular Microstrip Antenna by Inserting a Slot

In this work we were able to improve the reflection coefficient S11 and bandwidth BW of a rectangular microstrip antenna fed by a coaxial cable firstly by adjusting a the feed point and secondly by inserting a rectangular slot in the radiating element The results obtained using the HFSS software, have been compared by those published. These results are very satisfying

Higher Education Strategy in Responding to the Generative AI Revolution Decolonising the Standard Response and Action Planning Protocols

Background: The Generative Artifical Intelligence (AI) revolution is here, and the availability of resources such as ChatGPT has triggered rapid responses, actions, and strategy to address the implications this has on education in the United Kingdom (UK). ChatGPT and other Generative AI provisions are viewed as both problematic and beneficial by Higher Education Institutes (HEI’s). Alongside HEI’s, Higher Education England (HEE) Technology Enhanced Learning (TEL) forums are just 1 of many additional UK national groups prioritising the discussion, Continual Professional Development (CPD), and strategical approaches to analysing Generative AI, in determining how it should be addressed in education and practice. In terms of standard practice at London South Bank University (LSBU), the planning of projects and research to explore new technology lies predominantly with those deemed as the most “skilled”, “technical” or “aware” of the technology. People who are in specific roles within the institute are expected to “lead” on strategy, and this onus of responsibility often remains with them throughout the process from start to finish. Recognising the imbalance of power and the benefits of privilege this practice could create, a decision was made to explore and propose re-design of the current protocols in place at LSBU. Aim: Demonstrate the inclusion of a Decolonising step at the earliest designing stage of the project, to influence a practice change in how a HEI could respond to major items affecting education and any subsequent action-planning or project designing. Method: 3 academic members of staff, and 3 undergraduate students, of Black, Asian, African or Minority ethnicity, will be recruited. Individual and group sessions will be conducted using Microsoft Teams. Sessions will involve the participants leading on the discussion and development of the project proposal and associated documents being used in the larger study. This will occur between 19th May – 1st June 2023, after which the project proposal will be registered with the LSBU research ethics committee and internal registration system (Haplo). The Decolonising strategy and effects will be appraised by an independent investigator making objective comparisons to a version of the project protocol originally written by the Principal Investigator as a lone researcher. Themes and major highlights to demonstrate these comparisons, will be presented as the outcome for this project. All results and recommendations will be ready for presentation by no later than 15th June 2023. Expected Outcomes: Recommendations based on the outcome could feasibly affect changes in the future strategy for responding to major items requiring adaptation and evolution in education/practices, and potential other general and/or specific response/action-planning protocols, at London South Bank University. Additional information: This project forms part of a larger LSBU Generative AI project to explore a potential solution to the issues surrounding Generative AI in Higher Education

Performance of distributed mechanisms for flow admission in wireless adhoc networks

Given a wireless network where some pairs of communication links interfere with each other, we study sufficient conditions for determining whether a given set of minimum bandwidth quality-of-service (QoS) requirements can be satisfied. We are especially interested in algorithms which have low communication overhead and low processing complexity. The interference in the network is modeled using a conflict graph whose vertices correspond to the communication links in the network. Two links are adjacent in this graph if and only if they interfere with each other due to being in the same vicinity and hence cannot be simultaneously active. The problem of scheduling the transmission of the various links is then essentially a fractional, weighted vertex coloring problem, for which upper bounds on the fractional chromatic number are sought using only localized information. We recall some distributed algorithms for this problem, and then assess their worst-case performance. Our results on this fundamental problem imply that for some well known classes of networks and interference models, the performance of these distributed algorithms is within a bounded factor away from that of an optimal, centralized algorithm. The performance bounds are simple expressions in terms of graph invariants. It is seen that the induced star number of a network plays an important role in the design and performance of such networks.Comment: 21 pages, submitted. Journal version of arXiv:0906.378

Improving Forage Production Quantity and Quality Using Native Legume Species in Semi-Arid Agrosilvopastoral System

Agrosilvopastoral systems provide a range of livelihood services, either directly through forage production or indirectly by the beneficial effects on soil conservation, nutrient cycling, pollutant filtering, and biodiversity enhancement. Hence, improved silvopastoral systems have ample scope to rehabilitate degraded pastures to sustain livestock production, which remains a strong pillar for the livelihoods of the agrosilvopastoral communities. To evaluate the impact of Hedysarum coronarium L. (sulla) reseeding on pasture productivity, plant cover and plant density in semi-arid silvopastoral systems, an experiment was carried out in Sbaihia Site, Zaghouan Governorate, Tunisia during 2018-2019 growing season. The experiment was laid out under a randomized complete block design having 3 treatments including reseeding sulla; protection from grazing and control (free grazing) with three replications per treatment. Preliminary results showed that there were significant differences (p\u3c 0.05) among the three treatments. Reseeded sulla and protected plots recorded 100% plant cover while the control plots had less than 60%. The estimated biomass for the reseeded plots was four times higher than the biomass production in the protected plots and eleven times higher than the control plots. The highest plant density was recorded in the reseeded plots (163.2 plants/m2), followed by the protected plots (30.6 plants/m2) while the lowest value was recorded in the control plots (29.8 plants/m2). Based on these findings, it is concluded that reseeding well-adapted native forage species has a great potential to improve productivity of semi-arid silvopastoral systems, which would contribute towards reducing the feeding cost and, therefore, enhancing the income of the agrosilvopastoral communities

Marqueurs chromosomiques: à propos d'un cas

Les marqueurs chromosomiques peuvent être définis comme des petits chromosomes de structure anormale présents en addition aux 46 chromosomes humains connus. C'est un groupe hétérogène d'anomalies de structure chromosomique pouvant être avec ou sans conséquence phénotypique. Plusieurs tentatives sont réalisées afin de retrouver une corrélation génotype-phénotype lors de la présence d'un marqueur chromosomique. L'identification du marqueur, son origine et sa structure suit une stratégie bien codifiée actuellement allant d'abord de l'orientation clinique suivie des techniques de cytogénétique conventionnelle (caryotype métaphasique standard, bandes C, NOR) et de cytogénétique moléculaire (M-FISH, CGH, CGH array) puis une détection par des techniques plus ciblées (painting, sondes locus spécifique). Cet ensemble permet une meilleure analyse et correspondance clinico-génétique. Nous rapportons le cas d'un nourrisson présentant une dysmorphie faciale avec un retard psychomoteur dont l'analyse cytogénétique a révélé la présence d'un marqueur chromosomique avec un caryotype métaphasique 47,XX,+mar. A travers cette observation, nous mettons en valeur le rôle de la cytogénétique conventionnelle et moléculaire dans le diagnostic des syndromes dysmorphiques permettant une meilleure prise en charge du patient et un conseil génétique adéquat pour sa familleKey words: Marqueurs chromosomiques, anomalie chromosomique, analyse cytogénétique, dysmorphi

Two-phase piecewise homogeneous plane deformations of a fibre-reinforced neo-Hookean material with application to fibre kinking and splitting

Two-phase piecewise homogeneous plane deformations are examined in respect of a neo-Hookean matrix material reinforced with embedded aligned fibres characterized by a single stiffness parameter. The deformations are interpreted in terms of fibre kinking and fibre splitting. Previous work has shown that such a transversely isotropic material can lose ellipticity if the reinforcing stiffness is sufficiently large and the fibre direction is sufficiently compressed. In particular, it was shown that the associated failure modes are characterised by the emergence of weak surfaces of discontinuity that are normal to the fibre direction (the onset of fibre kinking) or parallel to the fibre direction (the onset of fibre splitting). Here, the analysis of strong surfaces of discontinuity, developing from weak ones, is studied. The considered model can give rise to piecewise smooth plane deformations separated by a plane stationary surface of discontinuity, interpreted as either kinking or splitting. Attention is restricted to (plane) deformations in which, on one side of the surface of discontinuity, the load axis is aligned with the fibre axis. Then the fibre stretch on this side of the discontinuity is a natural load parameter. The ellipticity status of the two-phase piecewise homogeneous plane deformations is shown to span all four possible ellipticity/non-ellipticity permutations. If both deformation states are elliptic, then a suitable intermediate deformation is shown to be non-elliptic. Moreover, it is shown that the mechanism is dissipative, and maximally dissipative quasi-static failure motion is examined in respect of both kinking and splitting. It follows that, firstly, surfaces of discontinuity perpendicular to the fibre direction, associated with fibre kinking, are nucleated followed by surfaces of discontinuity parallel to the fibre direction, associated with fibre splitting. With respect to kinking, such maximally dissipative kinks nucleate only in compression as weak surfaces of discontinuity, with the subsequent motion converting non-elliptic deformation to elliptic deformation

Investigation of Rheological and Geometric Properties Effect on Nonlinear Behaviour of Fluid Viscous Dampers

Global approval of the use of fluid viscous dampers to control the buildings response against dynamic loadings is growing. The idea behind incorporating additional dampers is that they will reduce most of the energy that is transmitted to the building during shaking event. The objective of this work is to identify and enhance the design parameters that control the nonlinear behaviour of fluid viscous damper subjected to sinusoidal excitation. For this, a numerical model of the flow inside the dissipater has been carried out based on finite volume method. A novel approach has been adopted to simulate elastic behaviour of the fluid, taking into account its compressibility by using the Murnaghan equation of state. A comparison between the calculations of the proposed model and the experimental tests was carried out. The model proved to be sufficiently accurate. A fluid flow analysis was then conducted to fully understand the internal mechanism of the damper. A parametric study was then performed by varying aspects such as dimensions, geometric relationships between components and fluid properties in order to better understand their effect on the non-linear behaviour of the device.  The results highlight the relationship between the parameters governing the shear thinning behaviour of the fluid and the non-linearity exponent of the damper. This makes it possible to better control the non-linear behaviour of the device by selecting the appropriate silicone oil and the appropriate geometric dimensions of its components