Comparison of Weighted Sum Fitness Functions for PSO Optimization of Wideband Medium-gain Antennas

In recent years PSO (Particle Swarm Optimization) has been successfully applied in antenna design. It is well-known that the cost function has to be carefully chosen in accordance with the requirements in order to reach an optimal result. In this paper, two different wideband medium-gain arrays are chosen as benchmark structures to test the performance of four PSO fitness functions that can be considered in such a design. The first one is a planar 3 element, the second one a linear 4 element antenna. A MoM (Method of Moments) solver is used in the design. The results clearly show that the fitness functions achieve a similar global best candidate structure. The fitness function based on realized gain however converges slightly faster than the others

Antenna Topologies for Microwave and Solar Energy Harvesting Purposes (Antenne-topologieën voor het oogsten van microgolf- en zonne-energie)

A rapid development of Wireless Power Transfer technology has been observed during the last decades. After Wi-Fi has become widely accepted, researchers and scientists now attempt to remove the last cable also in the area of energy transfer for certain applications. A typical application of WPT is Space-Based Solar Power (SBSP) harvesting. The concept of collecting solar power in space for use on Earth, which is one of the most promising power generation options which contribute to meeting global energy demands in the 21st century, calls for collecting solar energy in space across the entire wavelength of the spectrum. But before that energy can be supplied at DC to the users on earth or on other artificial aircrafts, three major energy-conversion steps are needed, 1) solar to DC, 2) DC to microwave at the microwave generators of the spacecraft's radiation system, 3) Microwave to DC at the rectenna rectifiers on earth or on other artificial aircrafts.In the current proposed SBSP, the rectenna (rectifier + antenna) is only involved in the third step to convert microwave to DC. The idea of using nano/optical rectennas (nano antenna or nantenna + rectifier) to harvest solar energy has been suggested in 1972. In recent years, this concept is re-called by scientists and researchers due to the rapid nano technology development. It is claimed that the efficiency of this type of topology may be much larger, even up to 90% for a single wavelength. This is much higher than the maximum efficiency (44%) of photovoltaic cells in a laboratory.The main objective of this thesis is to investigate the antenna as component in the Rectenna, both in the microwave and optical frequency bands. Both rectennas in such a system, one converting sunlight into DC power, and one working at microwave frequencies, after transferring the microwave power from the power satellite to earth, can be considered as the core components for any SBSP.For the microwave part, the target is to offer antenna designs that are superior to existing solutions. Thereto, the antenna design effort is mainly focusing on reducing the area for a certain bandwidth and gain, or in other words, to achieve the highest aperture efficiencies for a required bandwidth.For the optical part, the target is to investigate the radiation efficiencies and the matching conditions to the rectifier circuit that can be realistically reached in the conversion from sunlight to DC. In contrast to the situation at microwave frequencies, here the choice of the metal used to fabricate the antenna will prove to be crucial, due to the strong dispersive properties of metals.FOREWORD II CONTENTS IV ABSTRACT VIII SAMENVATTING X LIST OF ACRONYMS XII LIST OF SYMBOLS XIV CHAPTER 1 INTRODUCTION 1 1.1. WIRELESS POWER TRANSFER BASED ON THE RECTENNA APPROACH 1 1.2. NANO/OPTICAL RECTENNA FOR SOLAR ENERGY HARVESTING 2 1.3. SATELLITE SOLAR POWER SYSTEM (SSPS) 3 1.4. OBJECTIVES AND CONTENTS OF THE THESIS 4 CHAPTER 2 DESIGN FRAMEWORK 7 2.1. INTRODUCTION 7 2.2. FULL-WAVE EM SOLVERS 7 2.3. THE CHOICE OF THE DESIGN TOOL 11 2.4. OPTIMIZATION: GA AND PSO- UNDERLYING CONCEPTS 11 2.5. OPTIMIZATION FRAMEWORK 15 CHAPTER 3 OPTIMAL DESIGN OF A HIGHLY COMPACT WIDEBAND ARRAY 17 3.1. INTRODUCTION 17 3.2. THE DESIGN PROCESS 18 3.3. OPTIMIZATION 20 3.4. RESULTS 22 3.5. CONCLUSION 25 CHAPTER 4 HIGH APERTURE EFFICIENCY WIDEBAND MICROSTRIP ARRAYS FOR WPT/WLAN 27 4.1. INTRODUCTION 27 4.2. WIDEBAND THREE ELEMENT ARRAY 29 4.3. APERTURE EFFICIENCY ENHANCEMENT BY MINIMIZING THE AREA 37 4.4. STUDY OF THE THICKNESS OF AIR LAYER ON THE PERFORMANCE OF THE PROPOSED ARRAY 40 4.5. PSO OPTIMIZATION FRAMEWORK 42 4.6. ANTENNA DIVERSITY VERSUS PSO CONVERGENCE SPEED 44 4.7. APERTURE EFFICIENCY ENHANCEMENT BY INCREASING BROADSIDE GAIN 46 4.8. CONCLUSION 47 CHAPTER 5 COMPARISON OF WEIGHTED SUM FITNESS FUNCTIONS FOR PSO OPTIMIZATION OF WIDEBAND MEDIUM-GAIN ANTENNAS 49 5.1. INTRODUCTION 49 5.2. TESTED FITNESS FUNCTIONS AND PSO OPTIMIZER 51 5.3. 3-ELEMENT PLANAR ARRAY 54 5.4. 4-ELEMENT LINEAR ARRAY 58 5.5. CONCLUSION 61 CHAPTER 6 SYSTEMATIC FULL-WAVE CHARACTERIZATION OF REALISTIC METALLIC NANO DIPOLE ANTENNAS 63 6.1. INTRODUCTION 63 6.2. CHOICE OF METAL 64 6.3. DIPOLE MODEL 65 6.4. SOLVERS AND EXCITATION 66 6.5. RESULTS 70 6.6. CONCLUSION 78 CHAPTER 7 UPPER BOUNDS FOR THE SOLAR ENERGY HARVESTING EFFICIENCY OF NANO-ANTENNAS 79 7.1. INTRODUCTION 79 7.2. FROM INCIDENT WAVE TO RECEIVED POWER 81 7.3. EFFICIENCIES IN VACUUM 84 7.4. EFFICIENCIES ON A SUBSTRATE LAYER 87 7.5. EXTRACTION OF THE EFFECT OF THE MATERIAL PROPERTIES 89 7.6. CONCLUSION 91 CHAPTER 8 OPTIMAL SOLAR ENERGY HARVESTING EFFICIENCY OF NANO-RECTENNA SYSTEMS 93 8.1. INTRODUCTION 93 8.2. RECTENNA MODEL FOR SOLAR ENERGY HARVESTING 95 8.3. RESULTS 98 8.4. MAXIMUM DELIVERED POWER PER DIPOLE 107 8.5. CONCLUSION 108 CHAPTER 9 GENERAL CONCLUSIONS 109 9.1. CONCLUSION 109 9.2. FURTHER RESEARCH 111 BIBLIOGRAPHY 113 LIST OF PUBLICATIONS 119nrpages: 120status: publishe

Analysis of Pedestrian Characteristics in Urban Integrated Transportation Hub Station

As the theoretical research of pedestrian walking environment planning for safety, efficiency and comfort has become a hot research topic in recent years, the analysis of pedestrian characteristics in integrated traffic hub stations has become an indispensable content in the research of pedestrian flow. Research on pedestrian characteristics can help improve the hub The service level of the facilities in the station. In view of this, this article analyzes the pedestrian path selection, behavior walking characteristics, queuing characteristics and waiting characteristics in the hub station. The analysis results can provide a reference for the optimization of the facility layout in the hub station

The relationship between happiness and consumption expenditure: Evidence from rural China

We use data from the 2016 China Labor-force Dynamics Survey (CLDS) to examine the relationship between happiness and consumption expenditure of rural farmers in China. A two-stage residual inclusion approach is applied to tackle the potential endogeneity issue of happiness. The empirical results show that a higher level of happiness is associated with an increase in consumption expenditure in general. Further analysis reveals that higher levels of happiness are positively and significantly associated with higher expenditures on basic living goods, education and gifts. We also find that both household income and access to the Internet boost happiness and increase consumption expenditure. Happiness plays a larger role in improving the consumption expenditure of rural households compared with their urban counterparts. Our findings may suggest that improving rural income via income diversification strategies and investing in rural information and communication technology infrastructures would encourage rural farmers’ happiness, promote the upgrading of rural consumption and boost sustainable economic growth

An improved double-layer wideband CPW-to_CPS Balun

status: publishe

Hydrothermal Carbonation Carbon-Coated CdS Nanocomposite with Enhanced Photocatalytic Activity and Stability

Herein, a novel CdS nanocomposite is fabricated by a facile one-pot hydrothermal method assisted by glucose and polyvinylpyrrolidone (PVP). The as-prepared CdS is coated with a thin layer, which is determined to be hydrothermal carbonation carbon (HTCC) mainly containing semiconductive polyfuran. The as-prepared HTCC-coated CdS shows superior photocatalytic activity for the degradation of Rhodamine B (RhB) under visible light irradiation (λ ≥ 420 nm). The optimum sample (glucose content of 0.1 g) shows a degradation rate four-times that of pure CdS reference. Moreover, it also shows an improved stability, and the activity can be maintained at 96.2% after three cycles of recycling. The enhanced photocatalytic activity and stability of nanocomposite can mainly be attributed to: (i) The addition of PVP in the reaction solution can significantly increase the specific surface area of CdS and thus offer more active sites; (ii) The HTCC in the nanocomposite can expand the range of light absorption; (iii) The HTCC layer can form a heterojunction with CdS and improve the charge separation and transfer

Antenna Radiation Characterization for On-Body Communication Channel Using Creeping Wave Theory

International audienceCreeping wave theory is re-visited for BAN (Body Area Network) channel modeling. The formulation takes the characteristics of both antenna and human tissues into account. The field density at a certain distance from the radiating antenna can be directly determined by input power and on-body antenna gain. It is observed that the complicated on-body antenna gain measurement can be replaced by measuring antenna gain above infinitely large PEC (perfect electric conductor) plane to determine field density. Using time gating technique, the antenna gain above infinitely large PEC can be obtained by measuring continuous field on finitely large PEC, which is much easier to use in practice. The whole concept is validated through CST Microwave Studio. A very good agreement between the analytical model and full-wave simulation results is achieved

Potential application of a knowledgebase of iron metabolism of Acidithiobacillus ferrooxidans as an alternative platform

Background: Acidithiobacillus ferrooxidans is a facultative anaerobe that depends on ferrous ion oxidation as well as reduced sulfur oxidation to obtain energy and is widely applied in metallurgy, environmental protection, and soil remediation. With the accumulation of experimental data, metabolic mechanisms, kinetic models, and several databases have been established. However, scattered data are not conducive to understanding A. ferrooxidans that necessitates updated information informed by systems biology. Results: Here, we constructed a knowledgebase of iron metabolism of A. ferrooxidans (KIMAf) system by integrating public databases and reviewing the literature, including the database of bioleaching substrates (DBS), the database of bioleaching metallic ion-related proteins (MIRP), the A. ferrooxidans bioinformation database (Af-info), and the database for dynamics model of bioleaching (DDMB). The DBS and MIRP incorporate common bioleaching substrates and metal ion-related proteins. Af-info and DDMB integrate nucleotide, gene, protein, and kinetic model information. Statistical analysis was performed to elucidate the distribution of isolated A. ferrooxidans strains, evolutionary and metabolic advances, and the development of bioleaching models. Conclusions: This comprehensive system provides researchers with a platform of available iron metabolism-related resources of A. ferrooxidans and facilitates its application. How to cite: Zhou Z, Ma W, Liu Y, et al. Potential application of a knowledgebase of iron metabolism of Acidithiobacillus ferrooxidans as an alternative platform. Electron J Biotechnol 2021;51; https://doi.org/10.1016/j.ejbt.2021.04.00

Modification of Lipid-Based Nanoparticles: An Efficient Delivery System for Nucleic Acid-Based Immunotherapy

Lipid-based nanoparticles (LBNPs) are biocompatible and biodegradable vesicles that are considered to be one of the most efficient drug delivery platforms. Due to the prominent advantages, such as long circulation time, slow drug release, reduced toxicity, high transfection efficiency, and endosomal escape capacity, such synthetic nanoparticles have been widely used for carrying genetic therapeutics, particularly nucleic acids that can be applied in the treatment for various diseases, including congenital diseases, cancers, virus infections, and chronic inflammations. Despite great merits and multiple successful applications, many extracellular and intracellular barriers remain and greatly impair delivery efficacy and therapeutic outcomes. As such, the current state of knowledge and pitfalls regarding the gene delivery and construction of LBNPs will be initially summarized. In order to develop a new generation of LBNPs for improved delivery profiles and therapeutic effects, the modification strategies of LBNPs will be reviewed. On the basis of these developed modifications, the performance of LBNPs as therapeutic nanoplatforms have been greatly improved and extensively applied in immunotherapies, including infectious diseases and cancers. However, the therapeutic applications of LBNPs systems are still limited due to the undesirable endosomal escape, potential aggregation, and the inefficient encapsulation of therapeutics. Herein, we will review and discuss recent advances and remaining challenges in the development of LBNPs for nucleic acid-based immunotherapy

Relationship between Fungal Communities and Volatile Flavor Components during the Traditional Chinese Fermentation of Capsicum annuum L. Var. Dactylus M

Microbial diversity and dynamic changes play an important role in the production of fermented peppers. In this study, the relationship between fungal communities and the volatile flavor compounds of traditional Chinese fermented peppers was investigated by high-throughput sequencing technology. The results showed that Hanseniaspora was a dominant fungus during the whole fermentation course and accounted for 82.22% of the fungal community on average (ranging from 50.44% to 98.15%). Bidirectional orthogonal partial least squares (O2PLS) analysis between fungal community and volatile flavor compounds showed that Pichia, Hanseniaspora, Cryptococcus, Debarvomvces, and Trichosporon were closely correlated with the concentrations of the volatile flavor components such as α-terpineol, trans-3-tetradecene, 4-methylpentyl 3-methylbutanoate, and 11 other volatile flavor compounds. This study elucidated the dynamics of fungal communities and volatile flavor compounds during pepper fermentation and the correlation between them. Our analysis of the relationships between fungal communities and volatile flavor compounds advanced our understanding of the formation mechanism of volatile flavor compounds in fermented peppers