Revolutionizing Satellite Tracking: A Double Actuator System for Precise and Efficient Antenna Pointing Control

Randi I,   Rababa  M

 Abstract

  This study presents a double actuator model consisting of a DC motor plus lead screw in series with a piezoelectric stack (PZT). The DC motor and lead screw combination provide large displacements, while the PZT stack offers fast and precise positioning. The model was tested for antenna pointing control when tracking a satellite, where large amplitude motion with time constants measured in a few seconds is required to move between satellites, and fine control is required to track a given non-geostationary satellite. The control system uses the PZT stack and the DC motor together to track the reference signal, allowing for efficient and precise actuation. The linearization of the system and analysis of its frequency response provide valuable insights into the system's behavior, stability, and performance, and can help optimize its performance for specific applications. The results demonstrate that the double actuator model offers a promising solution for precise and efficient actuation in various applications, including robotics, aerospace engineering, and medical devices. Further research in this area is warranted to develop more efficient and effective actuation systems. 

  Improving the Performance of Tidal Power 

  Abdullah, T , Buhian, A

 Abstract

 The tidal turbines need to be retrieved from the seabed, so in this project a design for a lifting device able to be attached to a lifting point on the top of the tidal turbine to lift it to the surface, where the design can be operated from above the surface. The device will be supplied by guidance system from the subsea, where the device will be securely connecting to the nacelle. The main factors will be considered in this design are ; the lif materials and dimensions where the lifting mechanism  should be able to lift the weight of the tidal turbine approximately 20ton to the surface, and the guidance system design which should be 20m subsea. A new design for the mechanism of lifting was presented in this using solidworks software, and then the design was simulated using Finite Element Analysis. The finite Element analysis was obtained, by creating the suitable mesh size, and then the loads was applied to the design in order to find, the stress, the strain and the factor of safety. 

  Martin Pfeifr

 Abstract

 In this project the performance of using micro turbines to recover the waste energy in the buildings will be investigated where an extensive literature was obtained about the micro turbines and their applications, technology, and performance. The initial analysis was obtained according to different buildings highest to find the hydraulic power can be extracted. Applying energy balance on the system showed that the maximum power can be extracted from the microhydroulic turbine is 650W taken the efficiency of the whole system as 17%. It was found that there are some parameters should be considered during future work such as losses in pipe. The hydraulic and electrical power is proportional to the size of pipe where the flow rate at same head is high which leads to high potential energy. 

  Mahdi Hassan 

 Abstract

In this paper, the slats hydrates of CaCl2 and Vermiculite were tested as possible thermo-chemical heat storage materials for seasonal heat storage. These two materials were mixed to form one salt crystal sample and since two batches of Vermiculite were used then two crystal samples formed and tested. The carried out tests were TGA and DSC tests in which the loss in mass and heat flow were measured as temperatures increases from 25 to 150 degree. The energy analyses showed that two endothermic reactions occurred one at temperature of 29 C and the other at temperature of 45 C for the two samples. The reactions appeared as peak areas at the generated plots. Fully reversible reactions were governed the storage and release of thermal energy through the dehydration and hydration of chemical salts. At 45 C a mass loss of 3% was occurred. As a result, it was found that combining chemical salts within porous host matrices or what known as (Salt in matrix – SIM) has revealed to enhance the reaction rate of the chemical salts and reducing hysteresis throughout the charge and discharge cycles in addition to avoiding the deliquescence of the salt throughout the hydration phase. 

Lia Ras     Candian Mu  

 Abstract

In this study, compressive strength, modulus of elasticity and steel tensile coupon tests are performed to determine material properties. Sixteen hollow cold formed steel tubes and 48 concrete filled steel tube specimens are used for axial compression tests. The effects of width/thickness ratio (b/t), the compressive strength of concrete and geometrical shape of cross section parameters on ultimate loads, axial stress, ductility and buckling behavior are investigated. Circular, hexagonal, rectangular and square sections, 18.75, 30.00, 50.00, 100.00 b/t ratio values and 13, 26, 35 MPa concrete compressive strength values are chosen for the experimental procedure. Circular specimens are the most effective samples according to both axial stress and ductility values. The concrete in tubes has experienced considerable amount of deformations which is not expected from such a brittle material in certain cases. The results provide an innovative perspective on using cold formed steel and concrete together as a composite material.