Dynamic Modelling by Bond Graph Approach of Convective Drying Phenomena

Drying operations play an important role in food industries. They are often the last operation of the process of manufacturing a product, with a strong influence on the final quality. The processes are numerous and depend on the type and amount of product to be dried and water to be evaporated, the desired final quality, or the desired functionality for the dried product. In this chapter, we present a modeling study of heat transfer during drying a moist agricultural product placed in a hot air flow in a tunnel dryer with partial solar heating. The bond graph approach has been used for system modeling, and it is an object-oriented graphical approach based on an energetic description between subsystems. Some drying tests have been carried out on tomatoes and the experimental results are compared with the theoretical results for the validation of the developed model

Irathérapie dans la maladie de Basedow: place et efficacité

Le traitement de la maladie de Basedow repose sur trois thérapies: le traitement médical par les antithyroïdiens de synthèse, la chirurgie et l´irathérapie. L´objectif de notre étude était d´étudier la place et l´efficacité du traitement à l´iode radioactif dans le traitement de la maladie de Basedow. Une étude rétrospective portant sur 54 patients suivis pour une maladie de Basedow et traités par iode 131. On a mené en une étude descriptive des aspects épidémiologiques, cliniques, para cliniques et thérapeutiques et du le taux de rémission à court et à moyen terme. Le sex-ratio était de 0,45. L´âge moyen est de 38,33 ± 12,7 ans. Les signes fonctionnels les plus fréquemment retrouvés étaient l´amaigrissement, les tremblements et les palpitations. La FT4 moyenne est de 54,51 ± 19,56ng/dl (extrêmes: 8,90-100). La TSHus moyenne de nos patients était égale 0,074 ± 0,29 µUI/ml. Les antithyroïdiens de synthèse ont été prescrits chez 49 patients avec une persistance d´une hyperthyroïdie dans 83,67% des cas. L´irathérapie a été prescrite en première intention dans 9,3% et en 2ème intention dans 90,7% des cas. L´activité moyenne était égale à 13,29 mCi ± 1,46 avec des extrêmes allant de 10 à 15 mCi. Le premier contrôle hormonal post-irathérapie, réalisé après un délai moyen de 1,91 mois, a montré une rémission (eu- ou hypo-thyroïdie) chez 29 patients soit 53,7%. Après 12 mois de suivi, l´évolution était marquée par une rémission dans 88,88% (euthyroïdie chez 14,8% et l´hypothyroïdie chez 74%). L´irathérapie est un traitement efficace de la maladie de Basedow. Une dose forfaitaire forte d´iode radioactif permet d´obtenir un taux de rémission élevé

Distribution of HLA-DRB1/DQB1 alleles and DRB1-DQB1 haplotypes among Tunisian patients with autoimmune hepatitis

Background: Autoimmune hepatitis (AIH) is a chronic inflammatory disease characterized by necrotic inflammation leading to hepatocyte destruction. The association of human leukocyte antigens (HLA) with AIH development and onset is not fully elucidated especially in the Tunisian population.Objectives: The aim of this study was to determine the association of HLA class II alleles and DRB1-DQB1 haplotypes with AIH in Tunisian population.Patients and Methods: A total of 30 AIH patients and 60 healthy controls were included in the study. HLA class II typing was performed by Single-specific-primer polymerase chain reaction (PCR-SSP) technique.Results: Among 13 DRB1 and 5 DQB1 alleles resolved, our results show a positive association of HLADRB1 ⁄03 (38.3% vs. 21.6%, OR = 2.24, P = 0.028) and negative association of HLA-DRB1⁄11 (3.3% vs. 16.7%, P = 0.019). The analysis of DRB1-DQB1 haplotypes in cases and controls revealed 11-shared haplotypes with a frequency exceeding 1%. HLA-DRB1⁄11-DQB1⁄03 haplotype showed a decreased frequency in AIH patients (1.6% vs. 15.8%, P = 0.009) and may be considered as an haplotype of resistance to AIH.Conclusions: To our Knowledge, this is the first study performed to detect the HLA-DRB1 and DQB1 alleles associated with predisposition to AIH in Tunisian patients. The search for HLA predisposing genes to AIH may permit an earlier diagnosis allowing a better management and treatment of the disease in order to avoid liver transplantation

Investigation of a random-fractal antenna based on a natural tree-leaf geometry

In this paper, we investigate a new printed antenna based on the 2D image of a fractal tree-leaf geometry by studying the effect of the irregular boundary of the proposed antenna on its radiation characteristics. Both the impedance matching properties and the radiation patterns of the antenna are studied over the frequency band 1–6 GHz. Four configurations are designed by increasing the complexity of the structure, which ranges from iteration 0 to iteration 3. The fractal properties of the proposed tree-leaf antenna are then compared to those of a conventional fractal antenna with smooth edges. Following this, the proposed antennas are fabricated and characterized experimentally. Finally, results are analyzed and discussed, and a practical application for this new type of antennas is proposed

Thermal and electrical performance evaluation of hybrid air PV/T collector – numerical analysis and experimental study

The photovoltaic-thermal (PV/T) hybrid collector is the most generative technology solar energy, which has been invented to utilise electrical energy and heat from the solar system. This paper presents a numerical analysis and experimental validation of the thermal and electrical behaviour of the air PV/T collector based on the geometric design and the Tunisia climate conditions. PV/T system has lower thermal efficiency and higher electrical efficiency (14%) at high wind speeds. To improve the thermal efficiency, a sensitivity analysis studied across a range of the air channel depth (0.01–0.08 m) with different air mass flow rate. It was concluded that the thermal energy for a PV/T air system depends on the optimal depth and variations in mass flow rate

Novel Low-Cost Phase Shifters For Millimeter Wave Applications

Novel low-cost phase shifter that hybridize stepwise and continuously variable phase shifting mechanisms are presented in this work. A combination of straight and curved waveguides is used to realize the step-wise phase shifts, while the variable phase shifts are achieved by inserting one or more layers of metallic vias in the waveguide to achieve a differential phase up to 90°. An alternative scheme, which achieves the phase shift in the entire 0° to 360° range by mechanically changing the length of a telescopic guide, is also described

Chipless Rfid Tags\u27 Identification Algorithm By Using An Eigenmode Approach Combined With Signal-Processing Technique

A novel identification algorithm of chipless RFID tags by using an eigenmode analysis based on the SVD-decomposition, in conjunction with a signal-processing technique is presented. We start by extract a dominant eigenmode of the tag and show that we can significantly enhance the capability to carry out the scatterer recognition by exciting the tag with a transmitter antenna array with an excitation coefficient associated to the dominant mode. Later, a signal-processing algorithm is proposed to identify a tag based on the signals received by an array including fields scattered from the direct coupling between the transmitter and the receiver antennas in presence and in absence of the tag in the reader area. In addition, an identification vector is processed to detect the presence of multiple chipless tags simultaneously with range information and to identify a particular tag