Evaluation of rheological performance of a local modified bitumen by Styrene Butadiene Styrene polymer used in wearing course

In road construction, bitumen is the binder that gathered the different aggregates of road pavements. Bitumen, as a viscoelastic material, influences considerably the rheological behavior of bitumen concrete. The bitumen used in Algeria, showed its limits face to the traffic, which is increasing continuously. This research aims to valorize SBS polymer in wearing course by modifying a pure 35/50 bitumen. The present paper aims to study the polymer derived from styrene and butadiene (SBS) from the company Kraton Polymers International Ltd in the modification of a bitumen to improve its mechanical characteristics.To this end, the incorporation of SBS polymer was carried out according to two contents: 5.0 and 7.5% (by weight of asphalt), the objective being to evaluate the influence of this type of polymer on the rheological properties of the bitumen ordinary road including viscosity and modulus.The results reveal that the bitumen modified with 7.5% of SBS has better mechanical performance on the rigidity and the elasticity compared to the conventional bitumen. Recommendations have been made to implement a bitumen modification system to improve its quality and therefore the durability of bituminous pavements in the south of Algeria

Occurrence des sécheresses dans le bassin de la Medjerda (Tunisie)

La probabilité d'occurrence des sécheresses dans le bassin de la Medjerda (Tunisie) est calculée en se basant sur les totaux pluviométriques annuels de 35 postes sur une période de quarante ans. Les moments statistiques des volumes de déficits face à une demande en eau fixée sont estimés par la méthode des séries. Une fonction de répartition marginale des volumes de déficits est proposée, ainsi que des fonctions de répartition conditionnelles pour des durées sèches de un à six ans. Plusieurs lois de probabilité couramment utilisées en hydrologie sont étudiées. Des applications de ce modèle sont présentées.The probability of occurrence of drought in the Medjerda basin (Tunisia) is estimated using the stochastic process based on the measurement of total annual rainfalls taken in 35 stations over a period of 40 years.Marginal and conditional distributions of shortage volumes are analytically proposed at each location. Mean, standard deviation and skewness coefficients of shortage volumes are used for setting up a Person type III model. Then, similarly to I-D-F curves, drought duration curves are plotted within a given threshold. A general formulation of statistics of shortage volume population is given. It is expressed in terms of the position, the location and the scale parameters of the rainfall generator process, for a given threshold value. As an application, some useful distributions in hydrology are examined (Normal, Galton, Gamma, Weibull) and expected drought volumes are estimed.Model verification is performed using three stations of the basin for which the observed sample was extended to a period of 58 years. Comparison between observed and calculated statistics of shortage shows a good agreement. Expected shortage volumes are mapped using the average rainfall at each station as a threshold. A second threshold was based on an agricultural water demand. The corresponding water supply expected was mapped

STUDENT ENGAGEMENT IN NURSING SCHOOL: A SECONDARY ANALYSIS OF THE NATIONAL SURVEY OF STUDENT ENGAGEMENT DATA

Student engagement has received considerable attention in higher education research because of the link between increased student knowledge, greater student satisfaction with educational experience, and increased student retention and persistence. The National Survey of Student Engagement (NSSE) has been used since 2000 to assess engagement in undergraduate college students. NSSE results have been used to gain an understanding about levels of academic engagement for freshman and senior college students. Institutions use NSSE results to make changes in policies and practices to improve undergraduate education. This comparative descriptive study examined levels of undergraduate nursing students’ engagement during college by conducting a secondary analysis of NSSE data. The overall aim of this study was to gain a better understanding of nursing students’ levels of engagement at two points in time and comparing two geographic regions, and how they spent their time while in college. In a 2007 report, the National Leadership Council for Liberal Education and America’s Promise (LEAP) identified ten innovative high-impact practices in higher education. Since then, these practices have been implemented across the nation and have been associated with gains in student learning and personal development (Kuh, 2008). This study compared senior nursing students’ levels of engagement before and after these high-impact practices were recommended to see if engagement levels in senior nursing students differed between 2003 and 2010. Astin’s student involvement theory was used as a guiding framework for this study to examine how nursing students engage in the learning process and what educational resources nursing students use to become involved in the learning process. Astin’s theory focuses on what the college student does to be an active participant in the learning process and describes the environmental influences on college student development. Although statistically significant, the differences between the 2003 and 2010 nationwide cohorts of nursing students for the Level of Academic Challenge and Student-Faculty Interaction benchmarks were trivial. Senior nursing students were equally as engaged in 2010 as they were in 2003. This finding suggests consistency and stability in nursing education with regard to the Level of Academic Challenge and Student-Faculty Interaction benchmarks. Senior nursing students from Kansas and Missouri were compared to senior nursing students from all other states. Senior nursing students from KS/MO were similar to students from all other states in relation to Level of Academic Challenge and Active and Collaborative Learning benchmarks and how they spent their time in a typical 7-day week. Although statistically significant, the difference between the KS/MO cohort of nursing students and cohort of nursing students from other states for the Student-Faculty Interaction benchmark was trivial. In general, senior nursing students in 2010 were as engaged in their education as they were in 2003, reflecting stability in nursing education during this same time period. Senior nursing students from KS/MO were as engaged and spent their time in a similar manner as senior nursing students from all other states. This indicates that nursing students from these Midwest states have similar educational engagement as nursing students from other states and nursing education in the Midwest is consistent with the rest of the country. These findings of stability and consistency over time and across regions of the US are encouraging for nursing education. Nurse educators and higher-education administrators can build upon this strong foundation and make concerted efforts to further increase engagement in nursing students

Prédétermination des débits maximaux de crue par simulation Monte-Carlo de la pluie nette

Une méthodologie a été proposée pour la prédétermination des débits à partir de la pluviométrie. Il s’agit d’associer, en entrée, les simulations Monte Carlo de hyétogrammes de pluie nette avec un modèle d’hydrogramme unitaire à base de géomorphologie pour obtenir des hydrogrammes simulés en sortie. À la fin des simulations, l’analyse statistique des sorties permet d’apprécier l’étendue de la variabilité de la réponse du bassin aux événements pluvieux et de caractériser les débits et les temps de pointe. Un total de 44 simulations ont été menées pour chacun des 15 événements observés pour un petit bassin versant situé en Tunisie centrale. L’analyse des hydrogrammes générés a montré une assez faible dispersion des débits de pointe, d’une simulation à l’autre, pour un événement donné, et a mis en évidence la dissymétrie des distributions des débits et temps de pointe. L’exploitation des résultats de l’ensemble des simulations permet de dégager des relations empiriques caractérisant le comportement du bassin selon les débits de pointe, les temps de pointe, les temps de base et les volumes écoulés.The predetermination of peak discharges and flood volumes of ungauged basins is an important aspect of the management of surface waters, protection against floods, water supply, etc. In this study, a method is proposed for the predetermination of discharges from rainfall data. The method associates effective rainfall obtained from Monte Carlo Simulations (MCS) with a unit hydrograph based on geomorphology. The unit hydrograph (UH) based on geomorphology is selected knowing that the parameters can be obtained from topographic charts, soil charts and ground occupation charts, as well as from soil data. The UH used was produced from the Nash cascade model in which the scale and shape parameters were taken from the literature. These parameters depend on the hydrographical network, the Horton ratios and the average peak flow velocity, which is assumed to be constant throughout the network and with respect to time. The average peak flow velocity can be expressed as a function of 1) geomorphologic parameters such as the total surface area of the basin, the slope of the highest order stream, the Manning-Strickler coefficient, the width of the channel, the kinematic wave parameter of the highest order stream and the length of the main channel, and 2) the effective rainfall intensity and duration.With respect to effective rainfall intensities, the idea is to consider the effective rainfall as a vector of the parameters of the hydrological model, and then to use the MCS method to generate the corresponding components. The proposed simulation framework includes: 1) the specification of the data for which the geomorphologic parameters and the time increments are fixed for all simulations, whereas the duration of the total rainfall and the effective rainfall volume vary from one event to another, and constitute constraints determining whether or not simulations should be rejected, 2) the random drawing of effective rainfall intensities and durations, 3) the computation of resulting hydrographs and 4) the analysis of the simulated hydrographs, where the hydrographs are first simulated for each event and then simulated in their entirety to highlight indicators to characterize outputs.In order to statistically interpret the simulated hydrographs, the generated peak discharges were classified for each event, and their 25th, 50th and 75th percentiles were analyzed. The same treatment was applied to the simulated times to attain peak values. The use of the 25th and 75th percentiles makes it possible to evaluate the extent of the 50% interval of the simulated discharges, whereas the median and the mode make it possible to position values representative of the distribution of the generated discharges. The hydrographs are assumed have the same “recurrence” as their peak discharge. Hydrograph generation by the MCS method is a two step process: 1) the generation of effective rainfall intensities based on the assumption that the total volume is observed, and 2) the convolution of the unit hydrograph resulting from each interval of effective rainfall.The study site, Saddine1, is a small catchment with a surface area of 384 hectares. It is located adjacent to Makthar in Tunisia (northern latitude 35°48’06’’ and longitude 9°04’ 09’’) in a mountainous zone. The catchment is controlled by a small headwater dam and was monitored from 1992 to 1999. Observed over periods of five minutes, the maximum rainfall intensity was 324 mm/h and the minimal intensity was 10 mm/h. The maximum total rainfall recorded for an event was of 106 mm. The longest duration for an event was of approximately 5 hours (299 min) and shortest was 12 minutes. A great disparity in the volumes was also noted: the maximum volume observed was 67,200 m3 whereas the minimum was 1,275 m3. The peak discharges of the recorded hydrographs were very variable with a minimum/maximum ratio of about 1/1370. Indeed the maximum discharge observed was 85.6 m3/s, and the minimum discharge only 0.062 m3/s. The time to attain peak flows for the rainfall events varied from 10 to 120 minutes. The effective rainfall intensities were calculated using the infiltration index method, ϕ, which remains a method still largely used in spite of its rudimentary character. The effective rainfalls estimated for each event varied from 0.3 mm with 17.5 mm.Before using the MCS, the model was calibrated. The results of the calibration analysis showed that the calculated hydrographs were reasonable comparable to the observed hydrographs. In addition to the shape, the peak discharge and the peak time reconstitutions were satisfactory. A total of 44 simulations were carried out for each of the 15 events observed, of which 13 allowed for the identification of the distributions of effective rainfall intensities and durations. The remaining two events were used for the validation of the approach. The analysis of the generated hydrographs showed a rather weak dispersion of the peak output from one simulation to another, for a given event. Moreover, the discharges and times to attain peak discharge resulting from the generated hydrographs followed a dissymmetrical distribution. The observed values of the peak discharges and times to attain peak discharge represent realisations of output simulations with different probabilities of occurrence. In order to capitalize on the model, relationships between simulated peak discharges, times to peak discharge, base times and volumes were constructed

Poboljšanje tehnoloških svojstava i terapeutskog potencijala kus-kusa dodatkom tradicijskog preparata Issoufera: tradicionalna biljna medicina

Enrichment of food is a strategy to reduce the incidence of deficiencies in micronutrients in a population. Couscous is widely consumed in Algeria, thus the objective of this study was to obtain an enriched couscous with enhanced therapeutic potencies and with good physicochemical, technological, and microbiological characteristics. Three mass ratios of the traditional preparation Issoufer (10, 20, and 30 %) were added to wheat couscous, and then compared with a control couscous made 100 % of semolina. A significant (p < 0.05) increase was noticed in the ash, proteins, lipids, carbohydrates, phenolic compounds, flavonoids, and anti-radical activity values, for all the mass ratios of Issoufer powder. In contrast, the moisture and pH-value revealed a significant (p < 0.05) decrease in Issoufer powder. The acute toxicity study revealed no lethal effects and behavioural signs of toxicity at the tested doses (100, 250, 500, and 750 mg kg–1) of the extract of Issoufer during the 5 days of observation. The results of antibacterial activity showed diameters of inhibition zones had achieved 29.90±0.60 mm. Based on obtained results, Issoufer powder can be considered a good ingredient to develop functional couscous naturally enriched of secondary metabolites, and can be used in the prevention of several diseases, as well as used in the food industry.Obogaćivanje hrane je način da se smanji učestalost nedostataka mikronutrijenata u populaciji. Kus-kus je namirnica koja se u Alžiru konzumira u velikoj mjeri. Stoga je cilj ovog istraživanja bio dobiti obogaćeni kus-kus s poboljšanim terapeutskim potencijalom i dobrim fizikalno-kemijskim, tehnološkim i mikrobiološkim karakteristikama. Pšeničnom kus-kusu dodan je tradicionalni pripravak Issoufer (10, 20 i 30 %), te je smjesa uspoređena s kontrolnom čistom kus-kus krupicom. Znatno povećanje (p < 0,05) pepela, proteina, lipida, ugljikohidrata, fenolnih spojeva, flavonoida i anti-radikalne aktivnosti, zabilježeno je kod svih smjesa s dodanim Issoufer pripravkom. S druge strane, znatno (p < 0,05) su se smanjili udio vlage te pH-vrijednost. Studija akutne toksičnosti nije pokazala smrtonosne učinke i znakove toksičnosti pri ispitanim dozama ekstrakta Issoufera (100, 250, 500 i 750 mg kg–1) tijekom pet dana promatranja. Rezultati antibakterijske aktivnosti pokazali su da su promjeri zona inhibicije dosegli vrijednost od 29,90 ± 0,60 mm. Na temelju dobivenih rezultata, Issoufer prah može se smatrati dobrim sastojkom za razvoj funkcionalnog kus-kusa prirodno obogaćenog sekundarnim metabolitima te se može upotrebljavati za prevenciju više bolesti, ali i u prehrambenoj industriji

Deep Learning Approaches for Data Augmentation in Medical Imaging: A Review

Deep learning has become a popular tool for medical image analysis, but the limited availability of training data remains a major challenge, particularly in the medical field where data acquisition can be costly and subject to privacy regulations. Data augmentation techniques offer a solution by artificially increasing the number of training samples, but these techniques often produce limited and unconvincing results. To address this issue, a growing number of studies have proposed the use of deep generative models to generate more realistic and diverse data that conform to the true distribution of the data. In this review, we focus on three types of deep generative models for medical image augmentation: variational autoencoders, generative adversarial networks, and diffusion models. We provide an overview of the current state of the art in each of these models and discuss their potential for use in different downstream tasks in medical imaging, including classification, segmentation, and cross-modal translation. We also evaluate the strengths and limitations of each model and suggest directions for future research in this field. Our goal is to provide a comprehensive review about the use of deep generative models for medical image augmentation and to highlight the potential of these models for improving the performance of deep learning algorithms in medical image analysis

Firm’s Networking Competencies: Learning Orientation, Degree Of Internationalisation And The Role Of Strategic Motivation

In the current environmental context, organisations are facing tremendous pressure caused by several factors like globalisation and technological development. Consequently, firms are looking for different business models to deal with these issues. Inter-firm collaboration has been revealed as a prime source for developing distinctive competencies. Within this context, the research proposes networking competencies for firms to sustain their international growth. More specifically, this study examines the impact of learning orientation on firm networking competencies, and firm’s degree of internationalization as an outcome the firm networking competencies. The research, also, investigate the moderating role of strategic motivations using the social exchange theory and contingency theory. A model depicting relationships between these variables was developed based on the literature review. Adopting survey method, the model was tested using data gathered from 137 firms operating in the Malaysian manufacturing industry. The results reveal that two antecedents are positively related to the firm networking competencies. The results also indicate that firm networking competencies are significant predictors of the firm degree of internationalisation. Based on the findings theoretical contributions, implications were discussed for managers and policymakers. Finally, the study concludes with a number of limitations and directions for future research