Adsorptive performance of tetracarboxylic acid-modified magnetic silica nanocomposite for recoverable efficient removal of toxic Cd(II) from aqueous environment: equilibrium, isotherm, and reusability studies

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Miniaturized dual-band antenna array with double-negative (DNG) metamaterial for wireless applications

A miniaturized dual-band antenna array using a negative index metamaterial is presented for WiMAX, LTE, and WLAN applications. This left-handed metamaterial plane is located behind the antenna array, and its unit cell is a combination of split-ring resonator, square electric ring resonator, and rectangular electrical coupled resonator. This enables the achievement of a metamaterial structure exhibiting both negative permittivity and permeability, which results in antenna size miniaturization, efficiency, and gain enhancement. Moreover, the proposed metamaterial antenna has realized dual-band operating frequencies compared to a single frequency for normal antenna. The measured reflection coefficient (S11) shows a 50.25% bandwidth in the lower band (from 2.119 to 3.058 GHz) and 4.27% in the upper band (from 5.058 to 5.276 GHz). Radiation efficiency obtained in the lower and upper band are \u3e95 and 80%, respectively

PLC Virtualization and Software Defined Architectures in Industrial Control Systems

Today’s automation systems are going through a transition called Industry 4.0, referring to the Fourth Industrial Revolution. New concepts, such as cyber-physical systems, mi-croservices and Smart Factory are introduced. This brings up the question of how some of these new technologies can be utilized in Industrial Control Systems. Machines and production lines are nowadays controlled by hardware PLCs and this is considered as a state-of-the-art solution. However, the market demands are continuously increasing and pushing the industry e.g. to lower the operational costs and to develop more agile solutions. Industry 4.0 provides promising approaches to take a step forward and consider PLC virtualization. The purpose of this thesis was to evaluate PLC virtualization possibilities using different Software Defined Architectures. Requirements and benefits of different solutions were evaluated. The major objective of the case study was to compare container- and hypervisor-based virtualization solutions using Docker and KVM. The case study provides a modular and scalable IIoT solution in which a virtual PLC takes over the control instead of a hardware PLC. Node-RED was used as a runtime environment and an I/O-module was needed to set up a control loop test. Response time of the control loop was measured by capturing Modbus traffic with tcpdump. Multiple iterations were performed to show minimum, maximum, average, median and 90th pctl. latencies. The results indicate that the container-based solution has a smaller overhead than the hypervisor-based solution and it has a very little overhead in general. Peak latencies are a concern and even the average latencies show that this solution would not be suitable for any hard real-time or safety-related applications. Further investigation on the topic would be needed to estimate the actual potential of PLC virtualization on hard real-time applications. First of all, a more powerful hardware PC would be needed to perform such tests. Secondly, a faster industrial protocol than Modbus TCP/IP would be required. Perhaps another kind of approach would be needed to overcome the issues that were experienced in this case study. It would be interesting to test a direct communication between virtual PLC and I/O and use Node-RED nodes for example to trigger inputs. Anyhow, it seems that container-based solution is holding much promise as a virtualization approach

Fully fabric high impedance surface-enabled antenna for wearable medical applications

The compact and robust high-impedance surface (HIS) integrated with the antenna is designed to operate at a frequency of 2.45 GHz for wearable applications. They are made of highly flexible fabric material. The overall size is $45\times \,\,45\times 2.4$ mm3 which equivalent to $0.37\lambda \text{o}\times 0.37\lambda \text{o}\times 0.02$ mm3. The value of using HIS lies in protecting the human body from harmful radiation and maintaining the performance of the antenna, which may be affected by the high conductivity of the human body. Besides, setting the antenna on the human body by itself detunes the frequency, but by adding HIS, it becomes robust and efficient for body loading and deformation. Integrated antenna with HIS demonstrates excellent performance, such as a gain of 7.47 dBi, efficiency of 71.8% and FBR of 10.8 dB. It also reduces the SAR below safety limits. The reduction is more than 95%. Therefore, the presented design was considered suitable for wearable applications. Further study was also performed to show the useful of placing antenna over HIS compared to the use of perfect electric conductor (PEC). The integrated design was also investigated with the worst case of varying the permittivity of body equivalent model which shows excellent performance in term of reflection coefficient and SAR levels. Hence, the integrated antenna with HIS is mechanically robust to human body tissue loading, and it is highly appropriate for body-worn applications

Effect of a Flexible Polymer Dielectric and Magneto-Dielectric Composite Substrates in Antenna Array

This paper presents a comparative study on the effect of the polymer dielectric and magneto-dielectric substrates in antenna array. A 1x2 multilayer antenna array based on polymer magneto-dielectric (PDMS-Fe3O4) composite substrate have been designed and fabricated to evaluate the contribution of such substrate materials in antenna array performance and characteristics. The proposed antenna was compared with another antenna fabricated on multilayer dielectric polydimethylsiloxane (PDMS) substrates which used as a reference antenna. Both antennas are operating at 5.8 GHz. The simulated and measured results of the proposed magnetodielectric (PDMS-Fe3O4) antenna have shown an excellent enhancement in impedance bandwidth up to 1554 MHz (26.7%) compared to 470 MHz (8.1%) for a pure dielectric PDMS antenna that has the same substrate thickness. The gain and radiation efficiency of the magneto-dielectric based antenna is 7 dB and 60%, respectively, which indicate a good and satisfactory of antenna's performance

Compact and conformal multilayer antenna based on polymer nanocomposite substrate

This paper presents a compact and conformal multilayer single patch microstrip antenna based on a new class of polymer magneto-dielectric (PDMS-FeO) nanocomposite substrate. A 30% of nanoparticles (10 nm) of magnetite (FeO) iron oxide have been composited with 70% of polydimethylsiloxane (PDMS) to form PDMS-FeO layer. It has favorable electrical and mechanical properties such as low loss, flexible, light-weight, water resistant and transparency. The proposed antenna consists of a rectangular patch fed using 50 Ω microstrip line and its ground plane throughout the substrate. The proposed antenna have been simulated under four different conditions (free space, in water, bending condition, and on human body phantom) to evaluate such materials in different environments. The simulated and measured results of the proposed antenna show a reflection coefficient (S11) less than -20 dB at 5.8 GHz and has an excellent enhancement in its bandwidth (up to 983 MHz), Furthermore, it has radiation efficiency more 71% and gain of 6.35 dB

Left-handed Compact MIMO Antenna Array based on Wire Spiral Resonator for 5-GHz Wireless Applications

A compact coplanar waveguide-fed multiple-input multiple-output antenna array based on the left-handed wire loaded spiral resonators (SR) is presented. The proposed antenna consists of a 2 × 2 wire SR with two symmetrical microstrip feed lines, each line exciting a 1 × 2 wire SR. Left-handed metamaterial unit cells are placed on its reverse side and arranged in a 2 × 3 array. A reflection coefficient of less than −16 dB and mutual coupling of less than −28 dB are achieved at 5.15 GHz WLAN band

Flexible antenna on high permeability substrate for electromagnetic head imaging systems

The performance assessment and analysis of a wearable microstrip antenna based on high permeability material substrate in head imaging system is presented. The antenna is designed on polymer RTV6166-iron oxide substrate with relative permittivity and relative permeability of 3 and 5, respectively. The antenna consists of an inset-fed microstrip rectangular patch with dimensions of 44x72 mm, connected to 50 Omega feed. To evaluate the effect of the permeability in electromagnetic head imagining, the antenna is benchmarked against another similarly geometrized polymer RTV6166 based with unity permeability. Numerical simulations using CST Microwave Studio for both antennas are performed in free space and on a 3D human head model. The simulations results show that the antenna with high permeability exhibits better reflection coefficient (S-11) and electromagnetic penetration inside the human head tissues which will result in improved detection and image resolution

A 5 W high efficiency Class AB power amplifier for LTE base station application

This paper presents the design of a Class AB power amplifier operating at a frequency band of 3.4 GHz-3.7 GHz for LTE base station applications. The proposed design is targeted for a compact, low cost, high efficiency, and good linearity features. It based on GaN HEMT CGH40006P device manufactured by Wolfspeed/Cree. The design procedure and assessment of the presented power amplifier are described in this paper. The proposed input and output matching networks with stepped tapered microstrip transmission line have enhanced the transmission coefficients of the power amplifier, resulting in improvement of overall performance. The drain voltage and current waveforms are demonstrated to ensure the appropriate biasing point of class AB. At 1dB compression, the simulated results of the proposed class AB power amplifier with one tone input signal delivers power added efficiency of 59%, and 38 dBm output power. With code division multiple access (CDMA) signal, the power amplifier delivers a 51.9% of PAE, adjacent channel power ratio (ACPR) of below than -28.5 dBc at 2.25 MHz offsets, and delivers 37 dBm (~5 W) output power