currently operational non-destructive testing methods for pavements have many drawbacks that need improvement. This thesis investigates the possibility of utilizing the normal incidence reflection coefficient of acoustic waves in characterizing and studying of porous granular materials. The reflection coefficient of acoustic waves carries information about the physical parameters of materials. The fouling process in ballast layer and the compaction progress in sand and road base layers are the main focus of this study. Simplified fluid equivalent models are used to characterize and study the granular porous layers. The Delany- Bazley and Johnson- Allard models which require few non-acoustical material parameters are used in this analysis. A one dimensional problem which involves a porous layer backed by an infinite impedance surface has been solved in Matlab. The results from the two models have been compared and parametric studies of non-acoustical parameters have been also done. The study concludes the possibility of a new non-contact non –destructive testing method for unbound granular layers which utilize the reflection coefficient of acoustic waves.

The effect of papaverine on the albumin permeability-surface area product (PS), reflection coefficient (σ), and capillary filtration coefficient (K(f)) was examined in isolated rabbit lungs. Because PS and K(f) are functions of vascular surface area and permeability, we also compared papaverine with two other means of maximizing lung surface area: isoproterenol (1 x 10-7 M) and a mild increase in vascular pressure. Only lungs perfused with 0.1 mg/ml papaverine were significantly different from control. PS increased from control (2.80 ± 0.16 to 5.53 ± 0.20 ml · min-1 · g dry lung-1 x 10-2), whereas σ decreased from control (0.92 ± 0.01 to 0.78 ± 0.03). K(f) after papaverine was significantly lower than baseline predrug K(f) (5.60 ± 0.78 to 4.56 ± 0.53 ml · s-1 · cmH2O-1 · g dry lung-1 x 10-3). However, this group's predrug K(f) was higher than that of any other group. Our results indicate that papaverine increases albumin permeability and decreases endothelial selectivity. The isolated perfused lung appears fully recruited, because K(f) and PS did not increase with isoproterenol or increased vascular pressure. Papaverine should be used with caution in the Ringer-perfused lung.

We consider the Casimir effect for a scalar field interacting with another scalar field that is confined to two half spaces. This model is aimed to mimic the interaction of the photon field with matter in two slabs. We use Dirichlet boundary conditions on the interfaces for the fields in the half spaces and calculate their one-loop contribution to the wave equation for the other field. We perform the ultraviolet renormalization and develop a convenient formalism for the calculation of the vacuum energy in this configuration.

Yes / In the design of phase shifters, the modeling equations are too complicated and require some approximations to be derived correctly by hand. In response to this problem, this paper presents a generalized concept, algorithm, and MATLAB code that provide the exact modeling equations of the transmission parameters and the scattering parameters of any 90^o wideband stub-loaded phase shifter. The proposed code gives the modeling equations in term of variables for any number of stubs and characteristic impedance value by utilizing the symbol-based analysis of the MATLAB. It also illustrates the results as a function of normalized frequency relative to the center frequency f_o, and can be and can be tailored to any user-defined frequency range. As a matter of comparison, a three-stub wideband 90^o stub-loaded phase shifter is simulated using CST Microwave Studio and experimentally fabricated on Rogers RT5880 dielectric substrate with dimensions of 30×40×0.8 〖mm〗^3. The comparison reveals the accuracy of the proposed computerized modeling with -10 dB impedance bandwidth equal to 90% (0.55 fo-1.45 fo), (90∓5 degrees ) phase difference bandwidth equal to 100% (0.5 fo-1.5 fo), and negligible insertion loss. The novelty of this work is that the proposed code provides the exact modeling equations of the stub-loaded phase shifter for any number of stubs regardless the complexity of the mathematical derivations.

Yes / This article presents a miniaturized triple-band antenna for Internet of Things (IoT) applications. The miniaturization is achieved by using a split square ring resonator and half ring resonator. The antenna is fabricated on an FR4 substrate with dimensions of (33 × 22 × 1.6) mm3. The proposed antenna resonates at the frequencies 2.4 GHz, 3.7 GHz, and 5.8 GHz for WLAN and WiMax applications. The obtained −10 dB bandwidth for the three bands of the proposed antenna are 300 MHz, 360 MHz, and 900 MHz, respectively. The measured reflection coefficient values of the proposed antenna corresponding to each resonant frequency are equal to −14.772 dB, −20.971 dB, and −28.1755 dB, respectively. The measured gain values are 1.43 dBi, 0.89 dBi, and 1 dBi, respectively, at each resonant frequency. There is a good agreement between the measured and simulated results, and both show an omnidirectional radiation pattern at each of the antenna resonant frequencies that is suitable for IoT portable devices.

Magnetic Resonance Imaging (MRI) is a powerful non-invasive reconstruction tool used primarily in the medical community to produce high quality images of the human anatomy. Surface coils are Radio Frequency (RF) systems typically deployed for receiving the MR signals. Multiple surface coils, or an array of coils, are employed to obtain a localized improvement in the signal-to-noise ratio without limiting the field of view. In this research, a novel modeling and design method for decoupling RF surface coils in a phased array is investigated. This method employs an impedance transformation interface circuit along with a high input reflection coefficient preamplifier to decouple the coil. In this research report both the theory and design methodology are discussed in detail.

The CO2SINK (and CO2MAN) project is the first onshore CO2 storage project in Europe. The research site is located near the town of Ketzin, close to Potsdam in Germany. Injection started in June 2008, with a planned injection target of 100,000 tonnes of CO2. In February 2011, around 45, 000 tons of CO2 had been injected into the saline aquifer at an approximate depth of 630 m. This thesis focuses on time-lapse analysis of borehole seismic data, surface seismic data and reservoir characterization at the Ketzin site. Baseline Moving Source Profiling (MSP) data were acquired in the borehole Ketzin 202/2007 (OW2), along seven lines in 2007. The zero-offset Vertical Seismic Profile (VSP) data were acquired in the same borehole. The main objective of the VSP and MSP survey was to generate high-resolution seismic images around the borehole. After modeling and data processing, the sandy layers within the Stuttgart Formation can potentially be imaged in the VSP and MSP data whereas reflections from these layers are not as clearly observed in the 3D surface seismic data. 2D and pseudo-3D time-lapse seismic surveys were conducted at the Ketzin site. Interpretation of 2D baseline and repeat stacks shows that no CO2 leakage related time lapse signature is observable where the 2D lines allow monitoring of the reservoir. This is consistent with the time-lapse results of the 3D surveys showing an increase in reflection amplitude just centered around the injection well. The results from the pseudo-3D surveys are also consistent with the 3D seismic time-lapse studies and show that the sparse pseudo-3D geometry can be used to qualitatively map the CO2 in the reservoir with significantly less effect than the full 3D surveying. The 2nd pseudo-3D repeat survey indicates preferential migration of the CO2 to the west. There are no indications of migration into the caprock on either of the repeat surveys. Amplitude Versus Offset (AVO) analysis was performed on both 2D and 3D repeat surveys. A Class 3 AVO anomaly is clearly observed on the 3D repeat data and matches the synthetic modeling well. No AVO anomaly was observed on the 2D repeat data, which was anticipated, but the result shows signs of a pressure response at the reservoir level in the data. Reflection coefficients were calculated using surface seismic data (3D and pseudo-3D) at the site. Pre-injection calculations agree well with calculations from logging data. Post-injection calculations are in general agreement with the seismic modeling, but generally show higher amplitudes than those expected. The full 3D data show a better image of the reflection coefficients before and after injection than the pseudo-3D data and can potentially be used to make quantitative calculations of CO2 volumes. The pseudo-3D data only provide qualitative information.

L'étude expérimentale de la propagation et du rayonnement multimodal en guide large est abordée via des mesures par antennerie microphonique de la réflexion des modes pour différentes extrémités. Le banc expérimental est constitué d'un guide large fermé à une extrémité et débouchant sur différentes terminaisons à l'autre extrémité ; en paroi du guide sont branchées une source acoustique et deux antennes microphoniques. Chaque composant du banc est étudié pour améliorer les résultats de mesure. Une méthode de vérification des performances des haut-parleurs constituant la source et une méthode de pilotage de la source acoustique sont proposées pour favoriser la génération des différents modes de propagation de l'onde. Une méthode de calibration in-situ pour l'antenne est développée pour les différents modes. Un calcul des incertitudes pour l'estimation du coefficient de réflexion est proposé.Enfin les mesures sont effectuées pour différentes extrémités de guide : avec une bride, sans épaisseur, avec un écran infini. Le principe de la méthode de mesure de la réflexion des différents modes consiste à appliquer la méthode du doublet microphonique adaptée aux signaux issus de la décomposition modale obtenue au moyen de deux antennes de microphones. Les résultats de mesure pour le mode plan sont avantageusement comparés aux résultats théoriques issus de la littérature. Les résultats pour les premiers modes supérieurs montrent l'aptitude du système à extraire le coefficient de réflexion en module et en phase suffisamment précisément pour distinguer l'effet de la condition de rayonnement. / The experimental study of multimodal propagation and radiation in a wide guide is proposed via measurements of the reflection of modes for different terminations by using microphone arrays. The experimental bench consists of a wide guide closed at one end and ended with different terminations at the other end; an acoustic source and two microphone arrays are flush-mounted to the wall of the guide. Each component of the bench is first studied to improve the measurement results. A method of verifying the performance of the loudspeakers constituting the acoustic source and a method of controlling the acoustic source are proposed in order to facilitate the generation of the different modes of propagation of the wave. An in-situ calibration method for the microphone array is developed for the different modes. A calculation of the uncertainties for the estimation of the reflection coefficient is proposed.Then, measurements are performed for different guide terminations: with a finite flange, without flange, and with an infinite flange. The measurement of the reflection for the different modes consists of applying the method of two microphones to the signals from the modal decomposition obtained by means of two microphone arrays. Results of measurements for the plane mode are satisfactorily compared with theoretical results from the literature. Results for the first higher modes show the ability of the system to extract the reflection coefficient in modulus and in phase with sufficient precision to distinguish the effect of the radiation condition.

Although multi-element antenna (MEA) systems are already used in some modern wireless communication systems, the issue of mutual coupling between elements remains a challenge during MEA system design. Indeed, communications engineers continue to bemoan the fact that that the antenna elements are often still designed with such coupling as an afterthought. Thus, some authors have used the decoupling surface (DS) idea, whereby a separate DS is added to the MEA systems to reduce the above coupling. Whereas a DS may indeed lower the coupling levels between the elements of a given MEA system, it usually changes the other performance parameters as well, and in an undesirable way. Thus, this design route is a complicated one that is not easily affected. In this thesis we propose, for the first time, a new design process for MEA systems based on shape synthesis. The MEA system performance indicators are combined into an objective that sets the goal of the shape synthesis procedure. The application of the proposed design process is illustrated for three different geometrical arrangements of patch antennas and decoupling surfaces. This confirms the efficacy of the new design method.

No / This article presents a printed crescent-shaped monopole MIMO diversity antenna for wireless communications. The port-to-port isolation is increased by introducing an I-shaped conductor symmetrically between the two antenna elements and shaping the ground plane. Both the computed and experimental results confirm that the antenna possesses a wide impedance bandwidth of 54.5% across 1.6-2.8 GHz, with a reflection coefficient and mutual coupling better than -10 and -14 dB, respectively. By further validating the simulated and the measured radiation and MIMO characteristics including far-field, gain, envelope correlation and channel capacity loss, the results show that the antenna can offer effective MIMO/diversity operation to alleviate multipath environments.