This study provides data for the first time on the high levels of obesogenic food advertising on Turkish TV. This should alarm policy-makers to set limits on food advertising targeted towards children especially in countries like Turkey in which childhood obesity is emerging as an important public health issue.
VI. CONCLUSIONFour error estimation techniques are investigated for use with adaptive -refinement procedures, and the LCN method, for electromagnetic integral equations. For a test suite of targets, the estimators were successful at correctly locating high-error regions.Of particular interest is the successful performance of the "discontinuity in " estimator on the smooth targets under consideration. This estimator only imposes a computational cost of . Since it is unbounded at edges where the charge density is unbounded, some regularization must be applied for it to be used in that case. Residual estimators also work well and can handle general situations, but impose a cost of at least . This study suggests that adaptive refinement procedures can be efficient for integral equation formulations and that future efforts are warranted to extend these ideas to general three-dimensional problems. Abstract-A continuously tunable, circularly polarized X-band microfluidic transmitarray unit cell employing the element rotation method is designed and fabricated. The unit cell comprises a double layer nested ringsplit ring structure realized as microfluidic channels embedded in Polydimethylsiloxane (PDMS) using soft lithography techniques. Conductive regions of the rings are formed by injecting a liquid metal (an alloy of Ga, In, and Sn), whereas the split region is air. Movement of the liquid metal together with the split around the ring provides 360 linear phase shift range in the transmitted field through the unit cell. A circularly polarized unit cell is designed to operate at 8.8 GHz, satisfying the necessary phase shifting conditions provided by the element rotation method. Unit cell prototypes are fabricated and the proposed concept is verified by the measurements using waveguide simulator method, within the frequency range of 8-10 GHz. The agreement between the simulation and measurement results is satisfactory, illustrating the viability of the approach to be used in reconfigurable antennas and antenna arrays.
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INTRODUCTIONThis paper presents a reconfigurable dual-frequency rectangular slot antenna using MEMS (Microelectromechanical Systems) technology. MEMS devices have proven their usefulness in microwave applications with their reduced cost, improved perfonnance, and miniaturized dimensions feasible for batch fabrication. MEMS components seem to take the place of off-chip components in wireless communications [1]. Since RF MEMS components have tunable characteristics, the integration of these components with radiators may yield several advantages in terms of reconfigurability in polarization, frequency, and radiation pattem. The monolithic integration of tunable MEMS components with antennas can also reduce parasitic effects, the losses, system size, and costs. In last years, due to the interest to combine various wireless applications in a single system, reducing the system volume is a challenging issue. An antenna that can operate in multi-frequency might be an appropriate solution to reduce the system volume. This paper presents a new dual-frequency antenna structure implemented with the MEMS technology to achieve better performance than previous approaches. The tunable MEMS capacitors integrated with a dual-frequency rectangular slot antenna provide reconfigurability in frequency without any adverse effect on the radiation pattern. The following sections explains the antenna structure, simulation results, and fabrication process.
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