Synthèse et réalisations avec des zéros de transmission de filtres planaires miniaturisés à topologies fractales en substrat suspendu

Ce mémoire s'attache à proposer de nouvelles structures de filtrage planaires grâce aux itérations fractales et utilisant la technologie du substrat suspendu. Une technique de synthèse est développée. Elle permet dans un premier temps de caractériser les circuits prototypes passe-bas et passe-bande équivalents du filtre à concevoir. La matrice des coefficients de couplages peut ainsi être extraite à partir éléments des circuits équivalents. La synthèse permet de développer des filtres a réponse asymétrique, avec des zéros de transmission à gauche ou à droite de la bande passante, grâce aux rétro-couplages entre résonateurs non-adjacents. Les simulations électromagnétiques effectuées sous Momentum (ADS) permettent de caractériser les résonateurs miniaturisés fractals (facteur de qualité a vide, sensibilité aux tolérances...) et de déterminer les coefficients de couplages en fonction des gaps qui les séparent. Deux itérations fractales sont étudiées: l'itération de Minkowski appliquée à un résonateur bimode carré et l'itération de Hilbert appliquée à un résonateur linéique. Les résultats montrent surtout la possibilité de supprimer le premier harmonique grâce à ces itérations. Cinq exemples de réalisations sont montrés. Des filtres compacts avec de fortes rejections hors bande passante ont ainsi pu être conçus. Les résultats de mesure valident la synthèse et justifient l'intérêt de la miniaturisation par itération fractale.This thesis focuses on the development of new planar filtering structures using fractal iterations with the suspended substrate technology. A synthesis method is developed. It allows the characterization of equivalent lowpass and bandpass filter prototypes. The theoretical coupling coefficients matrix is extrapolated from the equivalent circuits' elements. The synthesis allows the development of asymmetrical frequency characteristics, with transmission zeroes on both sides of the passband, thanks to cross-couplings between non-adjacent resonators. Electromagnetic simulations carried out using Momentum (ADS) allow us to characterize miniaturized fractal resonators (unloaded quality factor, sensitivity...) and to determine the coupling coefficients along with their gap spacings. Two fractal iterations are studied; the Minkowski iteration is applied to a dual-mode square resonator and the Hilbert resonator is applied to a linear half-wavelength resonator. Results show the possibility to suppress the first harmonic thanks to these iterations. Five examples of realizations are presented. Compact filters with high out of band rejections are obtained. Measurement results validate the synthesis procedure and justify the interest of miniaturized filters using fractal iterations

Phytoremediation system for treating metals in ceramic industry wastewater

Phytoremediation system using aquatic plants is increasingly being applied by researchers due to its capability in metal removal. The study is aimed at evaluating the potential of selected aquatic plants by phytoremediation system to remove selected elements in ceramic industrial wastewater namely boron, copper, cadmium, chromium, ferum, manganese, and zinc. The system was tested with different types of plant, namely water hyacinth, water lettuce, and water spinach. Based on different plants, control and free flow method with hydroponic tank were applied in order to compare the effectiveness of circulation method by phytoremediation system. Phytoremediation system with applied volume of wastewater at 0.024m3 using three columns of phyto-rig was prepared to treat contaminants in ceramic wastewater using different plants within 11 days of treatment. Metal concentration analysis is determined by Inductively Coupled Plasma Mass Spectrometer (ICP-MS). The accumulation of contaminants in the plants was identified using Scanning Electron Microscope (SEM). Phytoremediation, which is a natural method, reduced the contaminants up to 90% by translocating metals in roots, leaves and shoots of the selected plants. Water hyacinth shows a ratio of removal percentage where Cr=Zn=Fe>Cd>Mn>Cu>B. Meanwhile, water lettuce shows removal percentage in the following order Fe=Zn>Cr=Cd>Mn>B>Cu. The ratio result of water spinach shows the removal whereZn>Cd>Fe>Mn>Cr>B>Cu. Based on the application of three types of plants, water hyacinth is the best phytoremediator as it can absorb high concentrations of contaminants. The concentration of metals in roots is much higher than in leaves and stems. This study successfully proved that these three plants are a good phytoremediator with high potential to remove contaminants in ceramic wastewater and will provide a useful guideline for on-site treatment

Diverse Spectrum of Presentation of Coronary Slow Flow Phenomenon: A Concise Review of the Literature

The coronary slow flow phenomenon (CSFP) is a disease entity characterized by slow progression of angiographic contrast in the coronary arteries in the absence of stenosis in the epicardial vessels. CSFP has a diverse presentation from mild chest discomfort to ST-segment elevation myocardial infarction. It can also have severe morbidity and mortality implications and can significantly hamper the quality of life of those affected. In this paper we present two patients with CSFP highlighting the diverse spectrum of presentation. A concise review of the literature is also provided emphasizing the epidemiology, pathogenesis, diagnostic parameters, treatment modalities, and clinical significance of this phenomenon

Avaliação quantitativa e qualitativa das manifestações patológicas de um edifício residencial no Distrito Federal: estudo de caso

O escopo deste trabalho é levantar as manifestações patológicas por meio de métodos quantitativos e qualitativos da garagem, fachadas, pilotis e cobertura e reservatório superior de um edifício residencial situado na cidade de Brasília, DF. Foram levantadas todas as patologias nos locais inspecionados. Foi aplicada a metodologia Gde, desenvolvida no Programa de Pós-Graduação da Universidade Federal de Brasília, que possibilita quantificar o grau de deterioração de estruturas de concreto na estrutura da garagem. Assim como, foi aplicada a metodologia do Instituto Brasileiro de Avaliação e Perícia de Engenharia para inspeções prediais no pilotis, fachadas e cobertura e reservatório superior. Elaborou-se um plano de ação para a correção das manifestações encontradas. Além disso, o plano de ação estabeleceu a criticidade de cada dano de acordo com as normas do IBAPE e, na garagem, conforme a metodologia desenvolvida na Unb. O plano de ação servirá como base para situar o síndico quanto ao estado do edifício, e auxiliá-lo na decisão de quais ações de recuperação adotar e quando adotá-las

Masters of Resilience: The Impact of Internal Communication in International Technology Companies

Today's dynamic and unpredictable VUCA world raises the question of how organizations can react to sudden changes in the most resilient way. This paper examines the contribution of internal communication as a management function to building individual resilience and its impact on the organizational level. The literature review reveals a prevailing theoretical focus within the current state of research, further entailing a lack of empirical work on the contribution of internal communication to strengthening resilience. In order to fill this gap, twelve semi-structured interviews were conducted with internal communication experts from international technology companies. The findings confirm the contribution of internal communication to value creation by building resilience potential as an intangible success factor in an increasingly volatile market. Additionally, hypotheses for further quantitative testing are provided. The associated new understanding of the role of employees calls for a reorientation of internal communication itself

Pneumatosis cystoidis intestinalis presenting as bowel perforation, a rare entity

AbstractIntroductionPneumatosis cystoides intestinalis (PCI) is an uncommon condition. This following article describes a case of primary PCI presenting as acute abdomen due to perforation of a small bowel cyst.Presentation of caseThis following article describes the case of an 88 year-old woman admitted at the hospital with peritonitis and consequently operated for a presumed bowel ischemia and perforation. However surgical exploration revealed perforated PCI.DiscussionThe pathophysiology of secondary PCI is poorly understood. Gas produced by Gas-forming bacteria may enter the mucosal barrier due and consequently this gas accumulates within the bowel wall. Also malnutrition can prevent the digestion of carbohydrates, which leads to increased bacterial fermentation, and production of large volumes of gas leading to distention and ischemia and subsequently the submucosal dissection of gas. Colonoscopy is helpful in excluding other colonic lesions and it shows the submucosal cysts that have a typical dual appearance: multiple white small cysts coupled to a sub-atrophic mucosa or larger cysts (up to 3cm) with a reddened overlying mucosa.ConclusionThe treatment unless complicated should be conservative even in the presence of pneumoperitoneum, after excluding complications

Arteriovenous Malformations of the Posterior Fossa : Focus on Surgically Treated Patients Presenting with Hemorrhage

BACKGROUND: Arteriovenous malformations (AVMs) of the posterior fossa are demanding lesions that often present with rupture. Studies including outcome analyses in surgically operated patients with ruptured infratentorial AVMs are scarce. Certain anatomic and demographic features have shown associations with postoperative outcomes. METHODS: Eighty-six patients with infratentorial AVM were collected from our AVM database. Fifty-four patients were admitted from 1990 onward, and their demographic, lesion, and treatment characteristics were analyzed. The cohort was further refined to 38 consecutive patients with surgically treated ruptured infratentorial AVM admitted to our center between 1990 and 2014, and statistical analyses of factors influencing outcomes were conducted. RESULTS: Twenty-seven patients (69%) had a favorable outcome at early follow-up and 24 (67%) had a favorable outcome at final follow-up. Factors associated with poor outcome in early recovery on univariate analyses were deep venous drainage of the lesion (odds ratio (OR 5.3; P = 0.037) and high Hunt & Hess score (P = 0.003). In the multivariate model, independent predictors for poor outcome were deep venous drainage (OR, 14.5; P = 0.010) and older age at admission (OR, 1.06; P = 0.028). The sole independent predictor for poor outcome at last follow-up was deep venous drainage (OR, 5.00; P = 0.046). The total follow-up time was 370 person-years. CONCLUSIONS: AVMs of the posterior fossa usually present with rupture and thus require prompt clinical treatment. The majority of surgically treated patients recover favorably. Our data show that venous drainage patterns have the greatest influence on the patient's postoperative condition. Other influencing factors include the severity of hemorrhage and patient age at admission.Peer reviewe

Parameters Variation to Estimate Performance Characteristics of 3-Phase Asynchronous Motor

The 3-phase asynchronous squirrel cage motors (SCIM) are main competitor machines placed instead of other motors in the commercial and industrial fields. The stator and rotor material selection and construction topology influence the electrical machine design. The results illustrated with the motor of a 15 KW, variable controlled speed, for the constant frequency of 50 Hz or 60 Hz. The motor parameters created inside the simulation model must be matched with the value of a standard parameter for SCIM to achieve a high dynamic response. This work examines the effect of the parameters variation for synchronous motor on the performance characteristics at starting point and at a load change for different time and speed regions. Changing of the rotor power is taken into consideration, this occurs with dynamic change of the hydraulic pump load from the valve. In the industrial applications, production, and manufacturing, till present there are still struggles to find the most holistic environment of the SCIM to achieve its efficiency at the lowest cost and same time control the motor performance, so we predicted the method of reducing the most effective motor parameters to improve the efficiency. The offline method used the SCIM parameters to calculate the time-varying current, torque, and rotor speed. The results illustrated that this method was fully consistent with the experiment tests and the standard theoretical values. A MATLAB program is used to simulate this study. The simulation model proved the feasibility of the proposed method with encouraging performance

Synthesis and electronic properties of alkyl- and alkyloxy-curcuminoids

Two series of p-alkyl- and p-alkoxy-substituted curcuminoids were synthesized. The validity of the proposed structures was checked on the basis of their high resolution mass spectra as well as NMR, IR and electronic spectra. The spectra were essentially similar for both series. NMR, IR and electronic spectra showed that the compounds exist mainly or exclusively as the enolic tautomer in their solutions. Theoretical study for the electronic spectra was conducted to account for the origins of the electronic transitions that are responsible for the UV-VIS bands. The theoretical calculations were done at the B3LYP/6-31G(d) level of theory and predicted that the similarity of the electronic spectra is may be due to the close resemblance of their molecular orbitals