Metaheuristic optimal design of adaptive composite beams

The first author also wishes to thank the support of Project IPL/2019/MOCHVar/ISEL.The integration of active materials in composite structures confers them the capability of adapting its behaviour when submitted to loads, overcoming a merely passive response. This adaptive character can be further optimized if the adequate design variable parameters are identified and selected. This work presents a study on the use of a metaheuristic bio-inspired technique to optimize (non-)skewed adaptive composite beams where material properties vary along the length. The results illustrate the performance of the analysis-optimization package implemented as well as the possible range of behaviours, beyond the optimal configurations achieved for the set of case studies.publishersversionpublishe

FORMULATION AND IN VITRO EVALUATION OF RITONAVIR FLOATING TABLETS BY MELT GRANULATION TECHNIQUE

Objective: The purpose of this study was to formulate Ritonavir floating matrix tablets by melt granulation technique in order to prolong its gastric residence time thereby increasing its bioavailability. Methods: The Ritonavir tablets were prepared by melt granulation technique, using carriers such as Gelucire 43/01, Gelucire 50/02 and Geleol pellets alone or in combinations. Ethyl cellulose was used as drug release rate retarding agent and sodium bicarbonate was used as gas generating agent. The prepared granules were subjected to pre and post compressional parameters. The formulations were optimized on the basis of matrix integrity, duration of floating, swelling behavior and In vitro drug release. Results: The drug-excipients compatibility studies were performed by FT-IR and the study revealed that there is no drug excipients interaction. A combined matrix system containing Gelucire 43/01: Gelucire 50/02 with 1:1 concentration along with HPMC K 15 M shows good drug release pattern with less floating lag time and increased floating duration. Conclusion: The in vitro drug release pattern of Ritonavir floating tablets was fitted to different kinetic models which showed the highest regression for Zero order kinetics with Higuchi mechanism. Keywords: Gelucire 43/01, Gelucire 50/02, Geleol pellets, Swelling behavio

An optimization strategy for customized radiotherapy head immobilization masks

Este trabalho foi financiado pelo Concurso Anual para Projetos de Investigação, Desenvolvimento, Inovação e Criação Artística (IDI&CA) 2016 do Instituto Politécnico de Lisboa. Código de referência IPL/2016/SoftImob_ISELAn effective head immobilization is an important requirement in radiotherapy treatment sessions, although it may also be thought in the future as a precious aid in brain medical imaging. Thus, the present work is focused on the stiffness optimization of a customized head immobilization mask, modelled upon the head reconstruction surface based on computerized tomography images. This paper proposes a strategy supported by a metaheuristic optimization technique and a metamodeling approach for the whole mask, illustrated at its most unfavorable region occurring in the gnathion region.info:eu-repo/semantics/publishedVersio

A retrospective study on the prevalence of urinary tract infections in a tertiary care hospital in Sangareddy district of South India

Background: Urinary tract infections (UTI) affect the portion of the urinary tract including kidneys, ureters, bladder, and urethra, and are among the commonly acquired nosocomial infections. Diagnosis based on the culture and sensitivity profile of the organism is highly beneficial for appropriate antimicrobial therapy of the individual.Methods: A retrospective study of culture isolates obtained from urine samples from different departments of a tertiary care hospital was performed in the period January 2018 to March 2020 in the district of Sangareddy, Telangana, India.Results: A total 204 samples of 1886 exhibited significant growth of organisms i.e., ≥105 colony-forming units of bacteria per millilitre (CFU mL-1). The most common pathogen isolated was Escherichia coli (47.05%), followed by Klebsiella pneumoniae (15.68%), Staphylococcus aureus (10.78%), Pseudomonas aeruginosa (10.78%), Enterobacter spp. (7.84%) and, Candida albicans (7.84%). The presence of Gram-negative organisms was found to be more than Gram-positive organisms among the samples cultured. Resistance was found to be more towards Amoxicillin (57.14%), followed by oxacillin (34%), cefotaxime (23.62%), clarithromycin (12.08%), erythromycin (12.08%), azithromycin (9.34%), linezolid (3.84%) and vancomycin (2.19%).Conclusions: Increasing levels of antimicrobial resistance by uropathogens emphasize the importance of therapy based on the culture and sensitivity of the organisms. Many uropathogens exhibit multi-drugs resistance. Regular surveillance and monitoring are useful in controlling the increasing resistance

Effect of BaTiO3/CoFe2O4 micro-topological textures on the coupled static behaviour of magneto-electro-thermo-elastic beams in different thermal environment

The use of composite materials with multifunctional capabilities is an increasing requirement for structures or components where the sensory function is accompanied by the diagnosis and the actuation functions, such as autonomic, adaptive or self-sustaining systems. In this context, the present study aims to characterize the coupled response of magneto-electro-thermo-elastic (METE) beams made from Barium Titanate (BaTiO3) and Cobalt Ferric Oxide (CoFe2O4) composite having various micro-topological textures, as well as their static response when submitted to different temperature distribution profiles. To this purpose, a three-dimensional finite element accounting for the coupling between the multiple physical fields in presence, is developed and implemented. The spatial heterogeneous BaTiO3/CoFe2O4 microstructure is also assessed by considering typical Body Centered Cubic (BCC), Face Centered Cubic (FCC) and Simple Cubic (SC) spatial packing arrangements. A special attention is paid to the influence of these micro-topological structures on the pyroeffects and its contribution towards the direct and derived quantities of the METE beam. The results obtained, suggest that the composite heterogeneous microstructure have a relevant influence on the static response of the METE beam in thermal environment.info:eu-repo/semantics/publishedVersio

Mechanical behavior of a sandwich plate with aluminum foam core, using an image-based layerwise model

Functionally graded materials are an advanced type of composite materials whose properties’ spatial evolution can be designed through the definition of the spatial distribution of the constituent phases’ mixture. This feature is particularly important if specific non-homogeneous properties’ requirements are required without introducing abrupt phases’ transitions, as happens in laminated materials. Porosities’ distributions within these materials, may constitute a design requisite for some applications, such as medical implants, but can also be highly undesirable in other cases such as for aeronautical applications. Regardless the specific situation, its characterization is of high importance to the prediction of the resulting materials’ behavior. This work is focused on the static and free vibrations’ analysis of a sandwich plate with a porous aluminum foam core and outer aluminum skins. The porosities’ distribution is modeled by different fitting functions, based on data obtained from a preliminary image processing stage of X-ray CT image of the sandwich plate’ cross-section. A layerwise approach is considered for subsequent numerical simulations’ purpose, where the sandwich skins’ kinematics are modeled using the first order shear deformation theory, while the core is modeled by a higher order shear deformation theory. Fitting functions’ influence on the plate’ behavior is also assessed.info:eu-repo/semantics/publishedVersio