Improving Electromagnetic Shielding with Metallic Nanoparticles

Due to major advantages (e.g. weight saving, maintenance advantages), the airframe manufacturers use more and more Polymer Matrix Composites (PMCs) in different parts of aircraft structures. But PMCs have the substantial disadvantage of low conductivity and therefore low Electromagnetic (EM) Shielding. Electromagnetic Interference (EMI) sources are all around and inside aircraft and can potentially threaten the immunity of the aircraft. Metallic meshes have been used to overcome this deficiency. However at high frequencies (UHF, SHF), most of the metallic mesh loses the performance. Regrettably most of the present and upcoming systems onboard of aircraft are functional in the mentioned range of frequencies. Furthermore, passengers are using more and more Personal Electronic Devices (PEDs) onboard of aircraft. Interference caused by PEDs are also in the same range of frequencies. Measured susceptibility caused by PEDs is higher in composite aircraft comparing to metallic one. To develop this disadvantage of composite aircrafts, design of a new lightweight shield, particularly for aeronautic applications, is needed. Metallic nanoparticles have a great potential to be used as new EM shields for aerospace applications. The promising results of this work encourage the designers to use metallic nanoparticles as a new shield for protection of composite aircrafts

Changes in some chemical properties of saline-sodic soils over time as affected by organic residues: An incubation study

Salinization and sodification of agricultural lands in arid and semi-arid regions of the world are two limiting factors in the crop production. This study was conducted to evaluate the effect of readily available agricultural residues on changing some chemical properties of saline-sodic soils. Wheat, potato, sunflower, and canola residues were separately added into three saline-sodic soils at a rate of 2% by weight and thoroughly mixed with soils. Control and treated soils were incubated for 168 days at a constant moisture and temperature. The pH, electrical conductivity (EC), soluble cations, available nitrate (NO3-) and phosphorous (P), cation exchange capacity (CEC), and exchangeable sodium percentage (ESP) were measured during the incubation. The EC increased in the response to the incorporation of plant residues, whereas the pH was reduced. The application of organic components in soils increased CEC and decreased ESP. The results showed that the maximum reduction in ESP was observed in the potato treatment because of the highest Ca2+ concentration. The average reduction in ESP of treated soil samples at the end of incubation followed this order: 16.1% (potato residue-treated soil) >12.7% (canola residue-treated soil) >11.1% (wheat residue-treated soil) >9.6% (sunflwer residue-treated soil). The potato residue was the most effective amendment in changing the chemical properties of saline-sodic soils in comparison with other organic residues. The results indicated that the application of organic residues had a positive impact on reducing the soil sodicity and improving the soil fertility depending on their chemical composition

Calcul des charges sur les ailes d'un avion

Ce mémoire est réalisé dans le cadre du projet MDO (Multidiciplinary Design Optimisation), dans lequel l'optimisation du calcul des charges (forces et moments) sur une l'aile de l'avion pour la compagnie Bombardier Aéronautique doit être analysée. Deux logiciels GAMBIT et Fluent on été utilisés pour ces types de calculs. Le premier logiciel, GAMBIT, nous a aidé à définir le maillage autour des différents profils de l'aile. Le deuxième logiciel, FLUENT, a été utilisé pour calculer les coefficients aérodynamiques de pression, portance et traînée. FLUENT utilise aussi les informations du logiciel précédent, GAMBIT pour créer toute l'information nécessaire à l'analyse de l'écoulement aérodynamique. On calcule les charges aérodynamiques pour les cas critiques de vol de l'avion en se basant sur les coefficients obtenus en utilisant les logiciels GAMBIT et FLUENT

Improving TC drill bit\u27s efficiency and resistance to wear by graphene coating

Displaying a two-dimensional pure crystal carbon structure, Graphene is the strongest, yet thinnest substance discovered by scientists. Coating tungsten carbide (TC) drill bits with graphene to evaluate the effect of graphene on the wear, as well as the rate of penetration of the drilling bit was examined in this research. Two evaluation approaches were employed: one with employing ANSYS Software and the second by employing atomic pressure chemical vapor deposition (APCVD synthesis) in the laboratory to produce a monolayer graphene coating. The simultaneous software-based and lab-based testing were performed to increase the credibility of the results and minimize the potential errors. Conducting the simulation using ANSYS, the maximum shear elastic strain, equivalent elastic strain, equivalent (von mises) stress, total deformation and maximum shear stress were investigated prior and after the graphene coating was applied on TC simulated bit. Total deformation was only slightly increased, while the maximum shear elastic strain was almost doubled, reflecting that the bit\u27s wear was significantly reduced after the coating. Lab-based APCVD synthesis results showed 34 % increase in compressive strength of the coated bit, in comparison to the uncoated one. The failure occurred for uncoated bit at 35 MPa, where the coated bit experienced failure at 46.9 MPa. The Von Mises stress test conducted on the coated and uncoated samples also indicated that this stress was 41 % less for the coated bit, in comparison to the uncoated one. Finally, two small-scale drilling operations, one using a 1inch graphene-coated TC bit and the other using a 1inch non-coated TC bit, were performed on a granite block, to evaluate the performance of the graphene-coated bit in practice. In a chosen 120-min time frame, 27 consecutive holes could be drilled by the graphene-coated TC bit, while 19 consecutive holes could be drilled by the uncoated TC bit, in identical drilling conditions. This implies a 42 % increase in ROP

Managing and Optimization of Energy Consumption and Offering Strategies to Materialize It

Undoubtedly, one of the most important challenges in this century in the world is energy crisis. On one hand, shortage of energy resources and its growing consumption and on the other hand , extreme usage of energy by different societies has endangered future life of human, polluted the environment and wasted national capitals. There are different methods to protect environment. The most common is saving that is not obtainable without correct management of energy as well as culture-making for correct using of energy. This paper tries to introduce useful and practical strategies to optimize energy consumption including Nanohnology, natural gas energy consumption, floor heat systems in buildings, using natural light and Building Energy Management System (BEMS

Managing and Optimization of Energy Consumption and Offering Strategies to Materialize It

Undoubtedly, one of the most important challenges in this century in the world is energy crisis. On one hand, shortage of energy resources and its growing consumption and on the other hand , extreme usage of energy by different societies has endangered future life of human, polluted the environment and wasted national capitals. There are different methods to protect environment. The most common is saving that is not obtainable without correct management of energy as well as culture-making for correct using of energy. This paper tries to introduce useful and practical strategies to optimize energy consumption including Nanohnology, natural gas energy consumption, floor heat systems in buildings, using natural light and Building Energy Management System (BEMS