The primitive ideal space of the partial-isometric crossed product by automorphic actions of the semigroup N2\mathbb{N}^{2}

Let $\mathbb{N}^{2}$ be the positive cone of the abelian lattice-ordered group $\mathbb{Z}^{2}$. Let $(A,\mathbb{N}^{2},\alpha)$ be a dynamical system consisting of a $C^*$-algebra $A$ and an action $\alpha$ of $\mathbb{N}^{2}$ on $A$ by automorphisms. The primitive ideal space of the partial-isometric crossed product $A\times_{\alpha}^{\textrm{piso}}\mathbb{N}^{2}$ of the system is completely described by using its realization as a full corner of a group crossed product and applying some works of Williams and Echterhoff.Comment: This is the initial version (20 pages). arXiv admin note: text overlap with arXiv:1701.0419

Infinitely many weak solutions for fourth-order equations depending on two parameters

In this paper, by employing Ricceri variational principle, we prove the existence of infinitely many weak solutions for fourth-order problems depending on two real parameters. We also provide some particular cases and a concrete example in order to illustrate the main abstract results of this paper

Numerical study of the effect of adding corona discharge based on plasma actuator on flow control performance in a horizontal axis wind turbine with rough surfaces

The use of renewable energy has recently become very common in most countries of today's society. Among these renewable energies, wind energy is one of the most attractive methods of mechanical energy production, and different methods of flow control, including active, semi-active and passive, have been investigated by various researchers. To control the fluid flow in an active way on the wind turbine blade, the corona discharge actuator based on plasma is considered the most appropriate method to reduce the fluid flow separation on the wind turbine blade. In this paper, we present a numerical simulation to integrate active load control using a corona discharge based on plasma actuators over the roughness blade. Effects of roughness, actuators voltage and frequency on aerodynamics parameters such as separation point, lift and drag coefficients have been showed. Present results showed that, the lift coefficient increase with increase in the voltage and frequency of plasma actuators. Overall, using the roughness for outer surface of blade would decrease the critical pressure coefficient by approximately 50% compared to that for the smooth surface

Sensitivity Optimization for a New Radio-Chromic Dosimeter (PRESAGE)

Introduction: Different dosimetric modalities (e.g., ionization chambers, semiconductors, TLDs, radiographic films) often have some problems determining isodose curves and percentage depth doses in high dose gradient regions. Research has been ongoing to develop portable high resolution dosimetry devices with accurate absolute dosimetry capabilities and easy data analysis. The ‘PRESAGE’ dosimeter is a type of polymer dosimeters with improved characteristics in comparison with older polymer dosimeters. It is solid, insensitive to oxygen, and can be made in different shapes. This work presents the fabrication process for a PRESAGE dosimeter and optimization of its radiation sensitivity. Material and Methods: The PRESAGE gel was formed in two steps. In the first step, Leuco Malachite Green was dissolved in a free radical initiator (carbon tetrachloride; CCl4) and a polyol, referred to as ‘Part B’ was added to the solution. The second step consisted of mixing the Leuco dye, a free radical initiator, and a catalyst with ‘Part B’ (a commercially available polyol), then blending them with Part A in equal proportions, placing the blended materials in an appropriate mold, and incubating at an optimal temperature under a pressure of 60 psi for 18 to 24 hours. After this period, the solution turned solid and was subsequently exposed using a cobalt-60 unit. Finally, the PRESAGE gel was read using a spectrophotometer. Results: The results showed that by changing the percentage of both Leuco dye and CCl4 to 4%, an optimum sensitivity of 0.0144 units/Gy can be reached. Discussion and Conclusion: Our results showed that the response function of the PRESAGE dosimeter is linear between 2.5 to 55 Gy. Using different material percentages to make the PRESAGE gel can result in a sensitivity variation ranging from 0.0099 to 0.0144 units/Gy

Fabrication and Optimization of a PAGATA Gel Dosimeter: Increasing the Melting Point of the PAGAT Gel Dosimeter with Agarose Additive

Introduction: The PAGAT polymer gel dosimeter melts at 30 ˚C and even at room temperature during the summer, so it needs to be kept in a cool place such as a refrigerator. To increase the stability of the PAGAT gel, different amounts of agarose were added to the PAGAT gel composition and the PAGATA gel was manufactured. Material and Methods: The PAGATA gel vials were irradiated using a Co-60 machine. Then, the samples were evaluated using a 1.5 T Siemens MRI scanner. The ingredients of the PAGATA normoxic gel dosimeter were 4.5% N-N' methylen-bis-acrylamide, 4.5% acrylamide, 4.5% gelatine, 5 mM tetrakis (THPC), 0.01 mM hydroquinone (HQ), 0.5% agarose and 86% de-ionized water (HPLC). Results: Melting point and sensitivity of the PAGAT gel dosimeter with addition of 0.0, 0.3, 0.5, 1.0, 1.5 and 2.0% of agarose were measured, in which the melting points were increased to 30, 82, 86, 88, 89 and 90°C and their sensitivities found to be 0.113, 0.1059, 0.125, 0.122, 0.115 and 0.2  respectively. Discussion and Conclusions: Adding agarose increased the sensitivity and background R2 of the evaluated samples. The optimum amount of agarose was found to be 0.5% regarding these parameters and also the melting point of the gel dosimeter. A value of 0.5% agarose was found to be an optimum value considering the increase of sensitivity to 0.125 and melting point to 86°C but at the expense of increasing the background R2 to 4.530