Improved description and monitoring of near surface hazardous infiltrate complexes by shear waves for effective containment reponse

Among numerous causes of fluid releases and infiltration in near surface, resurgence in such anthropic activities associated with unconventional resource developments have brought about a resounding concern. Apart from the risk of an immediate chemical hazard, a long term possible recurrent geo-environmental risk since can also be envisaged as for various prevalent stake holders and broader initiatives. Urgency and exactness for spatiotemporal containment and remediation promotes the devising of efficient methods for monitoring near subsurface flow complexes caused by such spills. Swave (Shear waves) spectral imaging results, in relevant context, of a controlled immiscible fluid displacement monitoring experimental study are analysed and inferred. Against the prospective method as well evaluated, Swave diffraction associated spectral peculiarities are examined, importantly, given background medium characteristics definitions invoking fresh insights of microscale significance alongside macroscale potential

The Role of Value Added Tax (VAT) in the Economic Growth of Pakistan

In Pakistan, General Sale Tax (GST) is essentially a Value Added Tax (VAT) and is an important source of revenue for balancing the government budgets. This study examines the extensive literature, concentrating on theory and empirical studies, on the relationship between VAT revenue and economic growth. It also evaluates critically the revenue performance of VAT in Pakistan during the period 1991-92 to 2011-12 with a larger focus on empirically estimating the role of VAT revenue in the economic growth (GDP) of Pakistan. Using Ordinary Least Square (OLS) Regression technique, the key outcome from this econometric study shows strong and positive impact of VAT revenue on the economic growth (GDP) of Pakistan. One per cent increase in the growth of net VAT revenue causes 0.24% increase in the growth of nominal GDP. The results of Granger Causality also confirm the existence of short run relationship between the growth of VAT revenue and economic growth (GDP) of Pakistan. Key words: Value Added Tax, Economic Growth, Pakista

Modélisation distribuée et évolutive du GaN HEMT

L’industrie de télécommunication et les satellites se base majoritairement sur les technologies Si et GaAs. La demande croissante des hauts débits de données entraine une facture élevée en énergie. En outre, la saturation de la bande des basses fréquences, le besoin des débits élevés et les exigences de la haute puissance imposait l’utilisation de la bande hautes fréquences. Dans le but de résoudre les problèmes cités auparavant, la technologie GaN est introduite comme un candidat prometteur qui peut offrir de la haute puissance, taille du circuit plus faible avec une meilleure stabilité mécanique aux environnements hostiles/milieux agressifs. À titre d’exemple, l‘agence spatiale européenne sont en cours de développement d’un circuit à base du GaN sur substrat en Si pour faible cout, une hautes performance et une grande fiabilité. La technologie GaN est assez mature pour proposer de nouveaux systèmes intégrés utilisés pour les puissances microonde ce qui permet une réduction considérable de la taille du système. Étant un semiconducteur à grande bande interdite, GaN peut offrir une haute puissance sous hautes températures (>225oC) avec une bonne stabilité mécanique. Elle présente un facteur de bruit faible, qui est intéressant notamment pour les circuits intégrés aux ondes millimétriques. À noter que la mobilité du GaN par rapport à la température est assez élevée pour proposer des amplificateurs dans la bande W. Avec le progrès du procédé de fabrication du GaN, notre objectif est l’introduction de cette technologie dans des applications industrielles. À cette fin, on désire avoir un modèle du dispositif qui correspond à la meilleure performance. Ensuite, on veut le valider dans une modélisation du circuit. Cette thèse, basée sur la technologie GaN unique développée au 3IT, a pour objectif l’amélioration de l’outil de conception en réduisant son erreur avec une validation de son utilisation dans la conception du circuit. Ce travail est réalisé pour la première fois au 3IT avec des résultats de simulation pour une conception idéale d’un circuit MMIC ainsi que sa démonstration. Une caractérisation des échantillons a été réalisée avec objectif d’extraction de données qui vont servir à l’alimentation de modélisation des transistors sur l’outil ADS. Une fois complétée, la modélisation a été validée par une modélisation des petits et grands signaux et a été testée par une mesure load-pull. Enfin, ce modèle a été utilisé lors de la conception d’un amplificateur pour les applications RF. L’innovation de ce travail réside dans la modélisation de la résistance d’une grille large sous forme de quadripôles parallèles à structure 3D (ou à résistances de grille distribuées) du transistor MOSHEMT GaN. La conception et la fabrication de l’amplificateur à haute puissance (HPA) aux fréquences microondes (≤4GHz) sont réalisés au LNN du 3IT et inclus une couche d’oxyde de grille afin de réduire le courant de fuite notamment pour les tensions Vgs élevées, la grille du transistor forme un serpentin pour fournir une puissance de sortie élevée avec un encombrement spatial minimal et une grille présentant une électrode de champ pour permettre d’augmenter la tension de claquage.Abstract : The telecommunication and satellite industry is mainly relying on Si and GaAs technologies as the demand for a high data rate is continuously growing, leading to higher power consumption. Moreover, the lower frequency band's saturation, the need for high data rate, and high-power force to utilize the high-frequency band. In pursuit of solving the issues mentioned earlier, GaN technology has been introduced as a promising candidate that can offer high power at a smaller circuit footprint and higher mechanical stability in harsh environments. For example, currently, the European space agency (ESA) is developing an integrated circuit with GaN on Si substrate for low cost, high performance, and high reliability. GaN technology is sufficiently mature to propose integrated new systems which are needed for microwave power range. This technology reduces the size of the system considerably. GaN is a wide bandgap semiconductor which can offer remarkably high power at high temperature (>225℃), and it is very stable mechanically. It presents a low noise factor, very interesting for a millimeter-wave integrated circuit. Finally, the mobility of GaN vs. temperature is sufficiently elevated to propose a power amplifier in W-Band. With the improvement of the GaN process, our objective is to introduce this technology for industrial applications. For this purpose, we wish to have a better model of the device that corresponds to the best performance and then validate it by using this model in a circuit. Based on the 3IT's GaN process, which is unique in its context, this thesis aims to improve the design kit by reducing the design model's error and validating it by using it in circuit design. This work is the first to realize in 3IT with simulation results to design an MMIC circuit for demonstration. I first characterized the new samples by performing different measurements than using these measurement data; transistor is modeled in ADS software. Once the model was completed, it is validated by small-signal modeling, and then the large-signal model is tested with non-linear capacitances, current source, and transconductance modeling. Finally, we used this model to design a power amplifier for RF application. The innovation comes from modeling large gate resistance as distributed gate resistance for GaN MOSHEMT transistor and then designing high-power amplifier (HPA) in the frequency range (≤ 4GHz) while using 3IT GaN process which includes first oxide layer to have low gate current and more voltage of Vgs, the second transistor is meander to have high power and third, field plate - gate for high breakdown voltage

On Some Properties of Quasi-Negative-Binomial Distribution and Its Applications

The quasi-negative-binomial distribution was applied to queuing theory for determining the distribution of total number of customers served before the queue vanishes under certain assumptions. Some structural properties (probability generating function, convolution, mode and recurrence relation) for the moments of quasi-negative-binomial distribution are discussed. The distribution’s characterization and its relation with other distributions were investigated. A computer program was developed using R to obtain ML estimates and the distribution was fitted to some observed sets of data to test its goodness of fit

On Some Negative Integer Moments of Quasi-Negative-Binomial Distribution

Negative integer moments of the quasi-negative-binomial distribution (QNBD) are investigated. This distribution includes recurrence relations which are helpful in the solution of many applied statistical problems, particularly in life testing and survey sampling, where ratio estimators are useful. Results study show the negative-binomial distribution when the parameter θ2 is zero and also indicate the mean of the QNBD model when its parameters are changed

Grain boundary precipitation in Inconel 718 and ATI 718Plus

Grain boundary precipitates in Inconel 718 and ATI 718Plus are important to control during hot working processes, since they can control the grain size. Precipitating excessive or insufficient amounts can be detrimental to the final component. Therefore, it is important for manufacturers to understand the formation and kinetics of grain boundary precipitation and the effect this has on mechanical properties. This review considers the background of grain boundary precipitation, including the effect of the thermal stability of γ' and γ" phases. In addition, the effect of stress on the grain boundary phases and their precipitation kinetics in different conditions are also included. Also, the impact of grain boundary precipitation on the mechanical properties is explored

Digital Forensic Analysis of Telegram Messenger App in Android Virtual Environment

The paper provides an in-depth analysis of the artifacts generated by the Telegram Messenger application on Android OS which provides secure communications between individuals, groups, and channels. Since the past few years, the application went through major changes and updates and the latest version’s artifacts varied from the previous ones. Our methodology is based on the set of experiments designed to generate the artifacts from various use cases on the virtualized environment. The acquired artifacts such as messages, their location, and data structure how they relate to one another were studied and were then compared to the older versions. By correlating the artifacts of newer version with the older ones, it shows how the application have been upgraded behind the scenes and by incorporating those results can provide investigators better understanding and insight for the certain evidence in a potential cybercrime case