Numerical simulation of two-chamber plasma sources using finite element method

Numerical simulation of plasma sources is very important. Such models allows to vary different plasma parameters with high degree of accuracy. Moreover, they allow to conduct measurements not disturbing system balance.Recently, the scientific and practical interest increased in so-called two-chamber plasma sources. In one of them (small or discharge chamber) an external power source is embedded. In that chamber plasma forms. In another (large or diffusion chamber) plasma exists due to the transport of particles and energy through the boundary between chambers.In this particular work two-chamber plasma sources with argon and oxygen as active mediums were onstructed. This models give interesting results in electric field profiles and, as a consequence, in density profiles of charged particles.

A method to determine volatile contaminants in polyethylene terephthalate (PET) packages by HDC-GC-FID and its application to post-consumer materials

A simple and low cost method to determine volatile contaminants in post-consumer recycled PET flakes was developed and validated by Headspace Dynamic Concentration and Gas Chromatography-Flame Ionization Detection (HDC-GC-FID). The analytical parameters evaluated by using surrogates include: correlation coefficient, detection limit, quantification limit, accuracy, intra-assay precision, and inter-assay precision. In order to compare the efficiency of the proposed method to recognized automated techniques, post-consumer PET packaging samples collected in Brazil were used. GC-MS was used to confirm the identity of the substances identified in the PET packaging. Some of the identified contaminants were estimated in the post-consumer material at concentrations higher than 220 ng.g-1. The findings in this work corroborate data available in the scientific literature pointing out the suitability of the proposed analytical method.

Drumming toward communitas : a case study of facilitated recreational music making and the Arthurian method

The phenomenon of communitas has been described as a moment 'in and out of time' in which a collective of individuals may be experienced by one as equal and individuated in an environment stripped of structural attributes (Turner, 1 969). In these moments, emotional bonds form and an experience of perceived 'oneness' and synergy may be described. As a result of the perceived value of these experiences, it has been suggested by Sharpe (2005) that more clearly understanding how this phenomenon may be purposefully facilitated would be beneficial for leisure service providers. Consequently, the purpose of this research endeavor was to examine the ways in which a particular leisure service provider systematically employs specific methods and sets specific parameters with the intention of guiding participants toward experiences associated with communitas or "shared spirit" as described by the organization. A qualitative case study taking a phenomenological approach was employed in order to capture the depth and complexity of both the phenomenon and the purposefiil negotiation of experiences in guiding participants toward this phenomenon. The means through which these experiences were intentionally facilitated was recreational music making in a group drumming context. As such, an organization which employs specific methods of rhythm circle facilitation as well as trains other facilitators all over the world was chosen purposely for their recognition as the most respectable and credible in this field. The specific facilitator was chosen based on high recommendation by the organization due to her level of experience and expertise. Two rhythm circles were held, and participants were chosen randomly by the facilitator. Data was collected through observation in the first circle and participant- observation in the second, as well as through focus groups with circle participants. Interviews with the facilitator were held both initially to gain broad understanding of concepts and phenomenon as well as after each circle to reflect on each circle specifically. Data was read repeatedly to drawn out patterns which emerged and were coded and organized accordingly. It was found that this specific process or system of implementation lead to experiences associated with communitas by participants. In order to more clearly understand this process and the ways in which experiences associated with communitas manifest as a result of deliberate facilitator actions, these objective facilitator actions were plotted along a continuum relating to subjective participant experiences. These findings were then linked to the literature with regards to specific characteristics of communitas. In so doing, the intentional manifestation of these experiences may be more clearly understood for ftiture facilitators in many contexts. Beyond this, findings summarized important considerations with regards to specific technical and communication competencies which were found to be essential to fostering these experiences for participants within each group. Findings surrounding the maintenance of a fluid negotiation of certain transition points within a group rhythm event overall were also highlighted, and this fluidity was found to be essential to the experience of absorption and engagement in the activity and experience. Emergent themes of structure, control, and consciousness have been presented as they manifested and were found to affect experiences within this study. Discussions surrounding the ethics and authenticity of these particular methods and their implementation has also been generated throughout. In conclusion, there was a breadth as well as depth of knowledge found in unpacking this complex process of guiding individuals toward experiences associated with communitas. The implications of these findings contribute in broadening the current theoretical as well as practical understanding as to how certain intentional parameters may be set and methods employed which may lead to experiences of communitas, and as well contribute a greater knowledge to conceptualizing the manifestation of these experiences when broken down.

La négociation mixte : observation de la négociation d’une convention collective

Dans le domaine des relations industrielles, on a vu apparaître, ces dernières années, différents changements au niveau des relations du travail, notamment en matière de négociation collective. En effet, de nouvelles formes de négociation ont vu le jour en réponse aux changements qui se sont produits sur le marché du travail. De façon plus précise, les théoriciens se sont penchés, d’une part, sur des méthodes de négociation moins conflictuelles et les acteurs concernés par la négociation collective ont su les mettre en pratique, d’autre part. Cependant, bien que certains aient tenté de substituer ces méthodes plus coopératives à la négociation traditionnelle de façon intégrale, les théoriciens et praticiens se sont aperçus qu’il était plutôt difficile de les adopter à l’état pur et ce, de façon alternative à la négociation traditionnelle. Afin d’optimiser les gains mutuels lors de la négociation d’une entente, les négociateurs vont plutôt opter pour un usage combiné des méthodes plus traditionnelles et des nouvelles formes dites plus coopératives; on parle alors de négociation mixte. Toutefois, peu d’études portant sur la négociation mixte ont été conduites. Nous croyons néanmoins que cette forme de négociation est plus appropriée, notamment en raison de la nature des enjeux traités à l’occasion d’une négociation collective. S’insérant dans ce contexte, l’objet de notre recherche est donc l’étude, par l’entremise d’un cas particulier, de la négociation mixte. De façon plus précise, nous cherchons à évaluer la méthode de négociation adoptée lors de la négociation collective ayant eu lieu entre le Centre de la petite enfance Pomme Soleil (CPE) et le Syndicat des intervenantes en petite enfance de Montréal (SIPEM) – CSQ en 2005. Afin d’y parvenir, nous avons vérifié les propositions et hypothèses suivantes : (1) la nature du climat des négociations précédentes a une influence sur la méthode de négociation de type mixte adoptée par les parties au cours de la négociation de la convention collective, (2) la nature du climat des relations industrielles a une influence sur la méthode de négociation de type mixte adoptée par les parties au cours de la négociation de la convention collective, (3) le passage du temps a un effet de transition sur la méthode de négociation de type mixte qui manifeste une dominante intégrative dans les étapes initiales de la négociation et une dominante distributive dans les étapes finales, (4) les négociateurs ayant reçu une formation à la négociation basée sur la résolution de problèmes ou basée sur les intérêts adoptent une méthode de négociation de type mixte à dominante intégrative, (5) l’expérience des négociateurs patronal et syndical a une influence sur la méthode de négociation de type mixte adoptée par les parties au cours de la négociation de la convention collective, (6) la stratégie de négociation initiale adoptée par les parties a une influence sur la méthode de négociation de type mixte au cours de la négociation de la convention collective et (7) la négociation des clauses à incidence pécuniaire donne lieu à une méthode de négociation de type mixte à dominante distributive. Grâce aux résultats que nous avons recueillis par l’entremise de l’observation de la négociation collective entre le CPE Pomme Soleil et le SIPEM, mais principalement par le biais des entrevues, nous sommes en mesure d’affirmer que, conformément à notre question de recherche, la négociation fut mixte, à dominante intégrative. Cependant, la question salariale, bien qu’elle ne fut pas abordée à la table de négociation mais avec le gouvernement provincial, prit une tangente distributive. En ce sens, nous pouvons dire que la négociation fut mixte et ce, de façon séquentielle.

Efficient estimation using the characteristic function : theory and applications with high frequency data

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Les marques du diable et les signes de l'Autre : rhétorique du dire démonologique à la fin de la Renaissance

Comment le motif de la marque insensible du diable a-t-il pu se frayer un chemin au sein du discours théologique, juridique et médical de la fin de la Renaissance jusqu'à s'imposer comme une pièce essentielle du crime de sorcellerie? Selon quels mécanismes et à partir de quels systèmes de croyance cette marque corporelle en est-elle venue à connaître une si large diffusion et une aussi grande acceptation tant chez les gens du livres que parmi les couches populaires? En cette époque marquée par la grande chasse aux sorcières et le développement de l'investigation scientifique, l'intérêt que les savants portent à cette étrange sémiologie constitue une porte d'accès privilégiée pour aborder de front la dynamique du déplacement des frontières que la démonologie met en oeuvre au sein des différents champs du savoir. Cette thèse a pour objectif d'étudier le réseau des mutations épistémologiques qui conditionne l'émergence de la marque du diable dans le savoir démonologique français à la charnière des XVIe et XVIIe siècles. Nous examinerons par quels cheminements l'altérité diabolique s'est peu à peu intériorisée dans le corps et l'âme des individus sous l'influence grandissante des vertus de l'empirisme, de la méthode expérimentale et de l'observation. En analysant la construction rhétorique de la théorie des marques du diable et en la reliant aux changements qui s'opèrent sur la plateforme intellectuelle de l'Ancien Régime, nous entendons éclairer la nouvelle distribution qui s'effectue entre les faits naturels et surnaturels ainsi que les modalités d'écriture pour en rendre compte.

Le phénomène d’influence entre pairs : observation des interactions sociales à l’intérieur de groupes d’entraînement aux habiletés sociales impliquant des élèves ayant des troubles du comportement et des pairs aidants sans trouble du comportement

Récemment, un nombre grandissant de jeunes ayant des troubles du comportement ont été intégrés dans les classes régulières. Afin de soutenir cette intégration, plusieurs programmes d’intervention ont émergé et été implantés dans les écoles québécoises. Parmi ces programmes, on retrouve le programme l’Allié, qui se distingue des autres, notamment, par l’utilisation de pairs aidants. Ce cadre d’intervention prometteur soulève cependant certains questionnements sur la possibilité d’influence négative entre les jeunes. L’objectif de l’étude est de décrire, dans une approche comportementale, le processus d'influence entre pairs. Une méthodologie d’observation systématique des interactions sociales est privilégiée. Les résultats indiquent qu’il n’y a pas eu d’influence négative dans les groupes l’Allié. Les comportements perturbateurs ont eu plus de chances de cesser lorsque les participants les ont ignorés, que lorsque les pairs ont réagi à ces comportements. L’ignorance intentionnelle d’un comportement semble donc constituer un processus d’influence important dans les groupes de jeunes.

Aportes del Aprendizaje Basado en Problemas (ABP) en la enseñanza de la Fisiología Animal en un programa de Zootecnia

En partant de quelques difficultés observées autour des aspects de la conceptualisation technoscientifique et de l’intégration de la de la théorie et la pratique dans l’apprentissage de la physiologie animale chez les étudiants du programme de Zootechnie de l’Université Nationale de Colombie, siège Medellín, cette recherche propose une stratégie didactique s’appuyant sur la méthode de l’Apprentissage Basé sur les Problèmes (ABP), appliquée spécifiquement aux sujets de thermorégulation et stress physiologique des animaux domestiques. Dans cette étude de cas on a travaillé avec un échantillon de huit étudiants à qui on a présenté dès la première session un problème didactique pour être résolu à travers le cours. Afin d’évaluer le processus on a réalisé trois enquêtes nommées Épreuves de Niveau de Formulation (NF) réalisées à différents moments de l’essai : l’une avant de commencer avec le sujet (NF 1), l’autre après la troisième classe théorique donnée et avant de faire la pratique sur le terrain (NF 2), et l’autre à la fin du processus (NF 3). Finalement on a réalisé des entretiens individuels avec chaque étudiant afin de connaître sa perception concernant la méthode. L’information obtenue a été soumise à une analyse qualitative et par des correspondances, par le biais du programme QDA Miner à travers de la révision et codification des textes provenants des enquêtes et de l’entretien individuel, complétés à leur tour par des observations sur le terrain, en analysant le changement conceptuel, la relation théorie-pratique et les correspondances entre les variables et les catégories établies. Parmi les principaux résultats obtenus on souligne le fait qu’après avoir appliqué l’ABP dans ce cours de Physiologie Animale le changement conceptuel a été favorisé et le problème formulé a servi comme connecteur entre la théorie et la pratique. En outre, on a observé la fusion des connaissances préalables avec les nouveaux acquis, l’apprentissage significatif, l’amélioration du niveau de formulation et l’augmentation de la scientificité des définitions; également il a mené à la solution viii de problèmes et à surmonter les obstacles épistémologiques comme la pluridisciplinarité et la non-linéarité. Il reste comme recommandation celle d’évaluer cette méthode dans d’autres sujets de la Physiologie Animale, dans d’autres sciences, dans des échantillons d’une taille majeure, ainsi comme approcher le sujet de l’évaluation appliquée directement à cette méthode.

Observation of Multiphoton Process in Liquid CS2 Using Pulsed Photoacoustic Technique

Pulsed photoacoustic measurements have been carried out in liquid CS2 using 532 nm radiation from a frequency doubled Nd:YAG laser. Variation of signal amplitude with laser fluence clearly indicates the role of multiphoton processes in the generation of photoacoustic effect. It is also shown that four photon induced dissociation and five photon induced ionization are likely processes in CS2 and 532 nm radiation.

Development of Free Space Method for Material Characterisation and GPR Study & A Case Study on Biological Samples

The thesis mainly focuses on material characterization in different environments: freely available samples taken in planar fonn, biological samples available in small quantities and buried objects.Free space method, finds many applications in the fields of industry, medicine and communication. As it is a non-contact method, it can be employed for monitoring the electrical properties of materials moving through a conveyor belt in real time. Also, measurement on such systems at high temperature is possible. NID theory can be applied to the characterization of thin films. Dielectric properties of thin films deposited on any dielectric substrate can be determined. ln chemical industry, the stages of a chemical reaction can be monitored online. Online monitoring will be more efficient as it saves time and avoids risk of sample collection.Dielectric contrast is one of the main factors, which decides the detectability of a system. lt could be noted that the two dielectric objects of same dielectric constant 3.2 (s, of plastic mine) placed in a medium of dielectric constant 2.56 (er of sand) could even be detected employing the time domain analysis of the reflected signal. This type of detection finds strategic importance as it provides solution to the problem of clearance of non-metallic mines. The demining of these mines using the conventional techniques had been proved futile. The studies on the detection of voids and leakage in pipes find many applications.The determined electrical properties of tissues can be used for numerical modeling of cells, microwave imaging, SAR test etc. All these techniques need the accurate determination of dielectric constant. ln the modem world, the use of cellular and other wireless communication systems is booming up. At the same time people are concemed about the hazardous effects of microwaves on living cells. The effect is usually studied on human phantom models. The construction of the models requires the knowledge of the dielectric parameters of the various body tissues. lt is in this context that the present study gains significance. The case study on biological samples shows that the properties of normal and infected body tissues are different. Even though the change in the dielectric properties of infected samples from that of normal one may not be a clear evidence of an ailment, it is an indication of some disorder.ln medical field, the free space method may be adapted for imaging the biological samples. This method can also be used in wireless technology. Evaluation of electrical properties and attenuation of obstacles in the path of RF waves can be done using free waves. An intelligent system for controlling the power output or frequency depending on the feed back values of the attenuation may be developed.The simulation employed in GPR can be extended for the exploration of the effects due to the factors such as the different proportion of water content in the soil, the level and roughness of the soil etc on the reflected signal. This may find applications in geological explorations. ln the detection of mines, a state-of-the art technique for scanning and imaging an active mine field can be developed using GPR. The probing antenna can be attached to a robotic arm capable of three degrees of rotation and the whole detecting system can be housed in a military vehicle. In industry, a system based on the GPR principle can be developed for monitoring liquid or gas through a pipe, as pipe with and without the sample gives different reflection responses. lt may also be implemented for the online monitoring of different stages of extraction and purification of crude petroleum in a plant.Since biological samples show fluctuation in the dielectric nature with time and other physiological conditions, more investigation in this direction should be done. The infected cells at various stages of advancement and the normal cells should be analysed. The results from these comparative studies can be utilized for the detection of the onset of such diseases. Studying the properties of infected tissues at different stages, the threshold of detectability of infected cells can be determined.

A semi-automatic method for segmentation and 3D modeling of glioma tumors from brain MRI

This work presents an efficient method for volume rendering of glioma tumors from segmented 2D MRI Datasets with user interactive control, by replacing manual segmentation required in the state of art methods. The most common primary brain tumors are gliomas, evolving from the cerebral supportive cells. For clinical follow-up, the evaluation of the pre- operative tumor volume is essential. Tumor portions were automatically segmented from 2D MR images using morphological filtering techniques. These seg- mented tumor slices were propagated and modeled with the software package. The 3D modeled tumor consists of gray level values of the original image with exact tumor boundary. Axial slices of FLAIR and T2 weighted images were used for extracting tumors. Volumetric assessment of tumor volume with manual segmentation of its outlines is a time-consuming proc- ess and is prone to error. These defects are overcome in this method. Authors verified the performance of our method on several sets of MRI scans. The 3D modeling was also done using segmented 2D slices with the help of a medical software package called 3D DOCTOR for verification purposes. The results were validated with the ground truth models by the Radi- ologist.

Evaluation Of A Novel Method Of Real Time Computer Assisted Spine Surgery

In this paper the effectiveness of a novel method of computer assisted pedicle screw insertion was studied using testing of hypothesis procedure with a sample size of 48. Pattern recognition based on geometric features of markers on the drill has been performed on real time optical video obtained from orthogonally placed CCD cameras. The study reveals the exactness of the calculated position of the drill using navigation based on CT image of the vertebra and real time optical video of the drill. The significance value is 0.424 at 95% confidence level which indicates good precision with a standard mean error of only 0.00724. The virtual vision method is less hazardous to both patient and the surgeon

New studies on the versatile roles of Polyaniline and its composites in polymer based optoelectronic and energy storage devices

From the early stages of the twentieth century, polyaniline (PANI), a well-known and extensively studied conducting polymer has captured the attention of scientific community owing to its interesting electrical and optical properties. Starting from its structural properties, to the currently pursued optical, electrical and electrochemical properties, extensive investigations on pure PANI and its composites are still much relevant to explore its potentialities to the maximum extent. The synthesis of highly crystalline PANI films with ordered structure and high electrical conductivity has not been pursued in depth yet. Recently, nanostructured PANI and the nanocomposites of PANI have attracted a great deal of research attention owing to the possibilities of applications in optical switching devices, optoelectronics and energy storage devices. The work presented in the thesis is centered around the realization of highly conducting and structurally ordered PANI and its composites for applications mainly in the areas of nonlinear optics and electrochemical energy storage. Out of the vast variety of application fields of PANI, these two areas are specifically selected for the present studies, because of the following observations. The non-linear optical properties and the energy storing properties of PANI depend quite sensitively on the extent of conjugation of the polymer structure, the type and concentration of the dopants added and the type and size of the nano particles selected for making the nanocomposites. The first phase of the work is devoted to the synthesis of highly ordered and conducting films of PANI doped with various dopants and the structural, morphological and electrical characterization followed by the synthesis of metal nanoparticles incorporated PANI samples and the detailed optical characterization in the linear and nonlinear regimes. The second phase of the work comprises the investigations on the prospects of PANI in realizing polymer based rechargeable lithium ion cells with the inherent structural flexibility of polymer systems and environmental safety and stability. Secondary battery systems have become an inevitable part of daily life. They can be found in most of the portable electronic gadgets and recently they have started powering automobiles, although the power generated is low. The efficient storage of electrical energy generated from solar cells is achieved by using suitable secondary battery systems. The development of rechargeable battery systems having excellent charge storage capacity, cyclability, environmental friendliness and flexibility has yet to be realized in practice. Rechargeable Li-ion cells employing cathode active materials like LiCoO2, LiMn2O4, LiFePO4 have got remarkable charge storage capacity with least charge leakage when not in use. However, material toxicity, chance of cell explosion and lack of effective cell recycling mechanism pose significant risk factors which are to be addressed seriously. These cells also lack flexibility in their design due to the structural characteristics of the electrode materials. Global research is directed towards identifying new class of electrode materials with less risk factors and better structural stability and flexibility. Polymer based electrode materials with inherent flexibility, stability and eco-friendliness can be a suitable choice. One of the prime drawbacks of polymer based cathode materials is the low electronic conductivity. Hence the real task with this class of materials is to get better electronic conductivity with good electrical storage capability. Electronic conductivity can be enhanced by using proper dopants. In the designing of rechargeable Li-ion cells with polymer based cathode active materials, the key issue is to identify the optimum lithiation of the polymer cathode which can ensure the highest electronic conductivity and specific charge capacity possible The development of conducting polymer based rechargeable Li-ion cells with high specific capacity and excellent cycling characteristics is a highly competitive area among research and development groups, worldwide. Polymer based rechargeable batteries are specifically attractive due to the environmentally benign nature and the possible constructional flexibility they offer. Among polymers having electrical transport properties suitable for rechargeable battery applications, polyaniline is the most favoured one due to its tunable electrical conducting properties and the availability of cost effective precursor materials for its synthesis. The performance of a battery depends significantly on the characteristics of its integral parts, the cathode, anode and the electrolyte, which in turn depend on the materials used. Many research groups are involved in developing new electrode and electrolyte materials to enhance the overall performance efficiency of the battery. Currently explored electrolytes for Li ion battery applications are in liquid or gel form, which makes well-defined sealing essential. The use of solid electrolytes eliminates the need for containment of liquid electrolytes, which will certainly simplify the cell design and improve the safety and durability. The other advantages of polymer electrolytes include dimensional stability, safety and the ability to prevent lithium dendrite formation. One of the ultimate aims of the present work is to realize all solid state, flexible and environment friendly Li-ion cells with high specific capacity and excellent cycling stability. Part of the present work is hence focused on identifying good polymer based solid electrolytes essential for realizing all solid state polymer based Li ion cells.The present work is an attempt to study the versatile roles of polyaniline in two different fields of technological applications like nonlinear optics and energy storage. Conducting form of doped PANI films with good extent of crystallinity have been realized using a level surface assisted casting method in addition to the generally employed technique of spin coating. Metal nanoparticles embedded PANI offers a rich source for nonlinear optical studies and hence gold and silver nanoparticles have been used for making the nanocomposites in bulk and thin film forms. These PANI nanocomposites are found to exhibit quite dominant third order optical non-linearity. The highlight of these studies is the observation of the interesting phenomenon of the switching between saturable absorption (SA) and reverse saturable absorption (RSA) in the films of Ag/PANI and Au/PANI nanocomposites, which offers prospects of applications in optical switching. The investigations on the energy storage prospects of PANI were carried out on Li enriched PANI which was used as the cathode active material for assembling rechargeable Li-ion cells. For Li enrichment or Li doping of PANI, n-Butyllithium (n-BuLi) in hexanes was used. The Li doping as well as the Li-ion cell assembling were carried out in an argon filled glove box. Coin cells were assembled with Li doped PANI with different doping concentrations, as the cathode, LiPF6 as the electrolyte and Li metal as the anode. These coin cells are found to show reasonably good specific capacity around 22mAh/g and excellent cycling stability and coulombic efficiency around 99%. To improve the specific capacity, composites of Li doped PANI with inorganic cathode active materials like LiFePO4 and LiMn2O4 were synthesized and coin cells were assembled as mentioned earlier to assess the electrochemical capability. The cells assembled using the composite cathodes are found to show significant enhancement in specific capacity to around 40mAh/g. One of the other interesting observations is the complete blocking of the adverse effects of Jahn-Teller distortion, when the composite cathode, PANI-LiMn2O4 is used for assembling the Li-ion cells. This distortion is generally observed, near room temperature, when LiMn2O4 is used as the cathode, which significantly reduces the cycling stability of the cells.

An alternative method for dating unknown tephras based on a segmented regression model

In CoDaWork’05, we presented an application of discriminant function analysis (DFA) to 4 different compositional datasets and modelled the first canonical variable using a segmented regression model solely based on an observation about the scatter plots. In this paper, multiple linear regressions are applied to different datasets to confirm the validity of our proposed model. In addition to dating the unknown tephras by calibration as discussed previously, another method of mapping the unknown tephras into samples of the reference set or missing samples in between consecutive reference samples is proposed. The application of these methodologies is demonstrated with both simulated and real datasets. This new proposed methodology provides an alternative, more acceptable approach for geologists as their focus is on mapping the unknown tephra with relevant eruptive events rather than estimating the age of unknown tephra. Kew words: Tephrochronology; Segmented regression