Development of an object-oriented finite element program: application to metal-forming and impact simulations

During the last 50 years, the development of better numerical methods and more powerful computers has been a major enterprise for the scientific community. In the same time, the finite element method has become a widely used tool for researchers and engineers. Recent advances in computational software have made possible to solve more physical and complex problems such as coupled problems, nonlinearities, high strain and high-strain rate problems. In this field, an accurate analysis of large deformation inelastic problems occurring in metal-forming or impact simulations is extremely important as a consequence of high amount of plastic flow. In this presentation, the object-oriented implementation, using the C++ language, of an explicit finite element code called DynELA is presented. The object-oriented programming (OOP) leads to better-structured codes for the finite element method and facilitates the development, the maintainability and the expandability of such codes. The most significant advantage of OOP is in the modeling of complex physical systems such as deformation processing where the overall complex problem is partitioned in individual sub-problems based on physical, mathematical or geometric reasoning. We first focus on the advantages of OOP for the development of scientific programs. Specific aspects of OOP, such as the inheritance mechanism, the operators overload procedure or the use of template classes are detailed. Then we present the approach used for the development of our finite element code through the presentation of the kinematics, conservative and constitutive laws and their respective implementation in C++. Finally, the efficiency and accuracy of our finite element program are investigated using a number of benchmark tests relative to metal forming and impact simulations

Pattern of Reaction Diffusion Front in Laminar Flows

Autocatalytic reaction between reacted and unreacted species may propagate as solitary waves, namely at a constant front velocity and with a stationary concentration profile, resulting from a balance between molecular diffusion and chemical reaction. The effect of advective flow on the autocatalytic reaction between iodate and arsenous acid in cylindrical tubes and Hele-Shaw cells is analyzed experimentally and numerically using lattice BGK simulations. We do observe the existence of solitary waves with concentration profiles exhibiting a cusp and we delineate the eikonal and mixing regimes recently predicted.Comment: 4 pages, 3 figures. This paper report on experiments and simulations in different geometries which test the theory of Boyd Edwards on flow advection of chemical reaction front which just appears in PRL (PRL Vol 89,104501, sept2002

Comparison of the efficiency of the nebulization of salbutamol, epinephrine and normal saline on treatment of bronchiolitis

Background: Bronchiolitis is a frequent cause of hospitalization. Despite the frequency of this pathology, there is not a single, widely practiced evidence-driven treatment especially using of nebulization. Present purpose was to compare which is efficient: nebulized salbutamol, epinephrine or normal saline.Methods: We have preceded to a prospective study from January 1st 2011 to March 31st 2012 including children between 29 days old and 2 years old.Results: We have included 90 patients divided in three groups and received nebulized salbutamol, epinephrine or normal saline. There was no real difference in the variables of the groups: clinical score, oxygen saturation, heart rate, temperature and weight but the hospitalization duration was shorter in the group who have been cured by normal salineConclusions: This study shows that salbutamol, epinephrine and normal saline can be used in the same situation but the normal saline has more advantages because of his low coast and the absence of risk of side effects

University Students Dealing with Sexually Transmitted Infections and HIV/AIDS: Knowledge and Practice, a Cross-sectional study Conducted in Fianarantsoa, Madagascar

This study aimed to evaluate the Knowledge and attitude of the academic students about sexually transmitted infections and HIV at the university of Fianarantsoa in 2018. Materials and methods: This was an analytical cross-sectional study conducted among undergraduate students at the University Andrainjato-Fianarantsoa. Knowledge was assessed using a score where each correct answer was given one point. Results: 1035 students were included, 67.7% (n=701) had good knowledge about STIs, and HIV/AIDS. Sexual transmission (83.9%; n=868) was the most known. On multivariate analysis, being a student at the faculty of medicine (p<0.001, aOR 137.3 [19.1-988]), faculty of Letters (p<0.001, aOR 4.5 [2.8-7.2)]), or the Normal Graduate School (NGS) (p<0.001, aOR 6.7 [3.3-13.7]), being tested for HIV before (p= 0.002, aOR 1.6 [1.2-2.2]) constitute the major factor of good knowledge about the sexual infections. The majority (71.8%, n=743) have had sexual intercourse before, and the median age of first sexual activities was 18 years (17-20). The use of Condoms (44.4%, n=460) was the most practiced in the STIs prevention method, followed by fidelity (19.8%; n=205) and abstinence (11.4%, n=118). Among the students, 29.3% (302) had high-risk sexual behavior in the last 3 months. Conclusion: The proportion of academic students with good knowledge of STIs and HIV is not satisfactory. There was a discordance between the knowledge of STI prevention and the daily university practice of the students

University Students Dealing with Sexually Transmitted Infections and HIV/AIDS: Knowledge and Practice, a Cross-sectional study Conducted in Fianarantsoa, Madagascar

This study aimed to evaluate the Knowledge and attitude of the academic students about sexually transmitted infections and HIV at the university of Fianarantsoa in 2018. Materials and methods: This was an analytical cross-sectional study conducted among undergraduate students at the University Andrainjato-Fianarantsoa. Knowledge was assessed using a score where each correct answer was given one point. Results: 1035 students were included, 67.7% (n=701) had good knowledge about STIs, and HIV/AIDS. Sexual transmission (83.9%; n=868) was the most known. On multivariate analysis, being a student at the faculty of medicine (p<0.001, aOR 137.3 [19.1-988]), faculty of Letters (p<0.001, aOR 4.5 [2.8-7.2)]), or the Normal Graduate School (NGS) (p<0.001, aOR 6.7 [3.3-13.7]), being tested for HIV before (p= 0.002, aOR 1.6 [1.2-2.2]) constitute the major factor of good knowledge about the sexual infections. The majority (71.8%, n=743) have had sexual intercourse before, and the median age of first sexual activities was 18 years (17-20). The use of Condoms (44.4%, n=460) was the most practiced in the STIs prevention method, followed by fidelity (19.8%; n=205) and abstinence (11.4%, n=118). Among the students, 29.3% (302) had high-risk sexual behavior in the last 3 months. Conclusion: The proportion of academic students with good knowledge of STIs and HIV is not satisfactory. There was a discordance between the knowledge of STI prevention and the daily university practice of the students

Molecular characterization of commensal Escherichia coli adapted to different compartments of the porcine gastrointestinal tract

The role of Escherichia coli as a pathogen has been the focus of considerable study, while much less is known about it as a commensal and how it adapts to and colonizes different environmental niches within the mammalian gut. In this study, we characterize Escherichia coli organisms (n=146) isolated from different regions of the intestinal tracts of eight pigs (dueodenum, ileum, colon, and feces). The isolates were typed using the method of random amplified polymorphic DNA (RAPD) and screened for the presence of bacteriocin genes and plasmid replicon types. Molecular analysis of variance using the RAPD data showed that E. coli isolates are nonrandomly distributed among different gut regions, and that gut region accounted for 25% (

The Effect of Keyboard-Based Word Processing on Students With Different Working Memory Capacity During the Process of Academic Writing

This study addresses the current debate about the beneficial effects of text processing software on students with different working memory (WM) during the process of academic writing, especially with regard to the ability to display higher-level conceptual thinking. A total of 54 graduate students (15 male, 39 female) wrote one essay by hand and one by keyboard. Our results show a beneficial effect of text processing software, in terms of both the qualitative and quantitative writing output. A hierarchical cluster analysis was used to detect distinct performance groups in the sample. These performance groups mapped onto three differing working memory profiles. The groups with higher mean WM scores manifested superior writing complexity using a keyboard, in contrast to the cluster with the lowest mean WM. The results also point out that more revision during the writing process itself does not inevitably reduce the quality of the final output

Win-win opportunities combining high yields with high multi-taxa biodiversity in tropical agroforestry

Resolving ecological-economic trade-offs between biodiversity and yields is a key challenge when addressing the biodiversity crisis in tropical agricultural landscapes. Here, we focused on the relation between seven different taxa (trees, herbaceous plants, birds, amphibians, reptiles, butterflies, and ants) and yields in vanilla agroforests in Madagascar. Agroforests established in forests supported overall 23% fewer species and 47% fewer endemic species than old-growth forests, and 14% fewer endemic species than forest fragments. In contrast, agroforests established on fallows had overall 12% more species and 38% more endemic species than fallows. While yields increased with vanilla vine density and length, non-yield related variables largely determined biodiversity. Nonetheless, trade-offs existed between yields and butterflies as well as reptiles. Vanilla yields were generally unrelated to richness of trees, herbaceous plants, birds, amphibians, reptiles, and ants, opening up possibilities for conservation outside of protected areas and restoring degraded land to benefit farmers and biodiversity alike