A compact low-power EM energy harvester using electrically small loop resonator

Electromagnetic (EM) energy harvester is a combination of an antenna or EM collector and a rectifier circuit. It is a concept that has seen applications in a variety of areas, as its essential purpose is to harvest and reuse the ambient microwave power. Compact system solutions for EM energy harvesting are presented and investigated in this work. The objective of this work is to reduce the size of the EM harvesters and simplify the fabrication process. A new approach to design a compact EM energy harvester which based on the concept of an electrically small square-loop collector, is proposed. Coplanar waveguide (CPW) transmission lines are utilized to build the half-wave rectifier. The input impedance of the rectifier is designed to be equaled to the conjugate of the impedance of the square-loop collector at the operating frequency. This method not only reduces the mismatch loss, but also reduces the overall size and simplifies the complexity of the system. The efficiency and the DC output power of the design are examined with respect to the power density on the EM harvester surface. Measurements demonstrate that the system is efficient to harvest EM energy in a low power density environment and generate a reasonable DC power. The proposed EM energy harvester is compact, easy to fabricate and integrate into other devices, and suitable for different energy harvesting applications. The mechanical flexibility of the proposed compact EM energy harvester is also discussed. The EM energy harvester is redesigned and fabricated on a thin flexible substrate. The performances are measured with respect to frequency in both planar and curvature configurations. The results show that the operating frequencies for both planar and curvature configurations do not vary. Furthermore, the output power of the two configurations at the operating frequency are very close to each other. The proposed flexible EM energy harvester requires a simpler fabrication process and a smaller size when compared to the previous work reported in the literature for EM energy harvesting at 2.45 GHz. A single element of EM energy harvester is insufficient for powering common devices. Therefore, two low-cost techniques are proposed and used to increase the capability of the system. In the first method, a parabolic reflector is designed, fabricated and placed behind the system to reflect the beam of parallel rays and concentrates the radiation power at the harvester surface. An alternate technique to boost the output DC power is based on using multi-square-loop collectors. Instead of using a rectifier circuit for each loop collector, multi collectors are combined before feeding into a single rectifier circuit. The experimental results show that these two techniques have significant improvement in the DC output power. The parabolic reflector technique can improve the DC output power by 35%, while in the case of the multi collectors technique, 4 times higher DC output power can be achieved

A quantum heat exchanger for nanotechnology

In this paper, we design a quantum heat exchanger which converts heat into light on relatively short quantum optical time scales. Our scheme takes advantage of heat transfer as well as collective cavity-mediated laser cooling of an atomic gas inside a cavitating bubble. Laser cooling routinely transfers individually trapped ions to nano-Kelvin temperatures for applications in quantum technology. The quantum heat exchanger which we propose here might be able to provide cooling rates of the order of Kelvin temperatures per millisecond and is expected to find applications in micro- and nanotechnology

Use of Dietary Supplements among Professional Athletes in Saudi Arabia

The objective of this study was to understand the usage patterns of dietary supplements among professional athletes in Saudi Arabia. The survey consisted of sixteen questions divided into four categories: use of supplements, reason for consumption of supplements, personal beliefs about supplements, and behavior. The questionnaires were given to the three teams residing in Riyadh: Al Hilal, Al Nasr, and Al-Shabab. Out of the 105 athletes surveyed, we found that only 98 are currently taking dietary supplements and the mean age and standard deviation were 25.74 ± 2.90. The survey results showed a high percentage of athletes (93.3%; = 98) using different dietary supplements throughout the season, 43.8% ( = 43) reported using supplements for performance, and 32.6% ( = 32) believed in health benefits as a reason for using dietary supplements. Our results showed that a total of 87 (88.7%), 81 (82.6%), and 51 (52.0%) athletes are consuming sports drinks, vitamin C, and multivitamins, respectively. Meanwhile, those supplements ranking among the least used included omega 6 (18.6%), creatine (16.3%), and Ginkgo biloba (10.2%). A majority of athletes indicated that their use of supplements was for the purpose of improving their health and performance

Probiotic Characteristics and Health Benefits of the Yogurt Bacterium <em>Lactobacillus delbrueckii</em> sp. <em>bulgaricus</em>

Yogurt is a good source of several micronutrients and has played an important role in human nutrition. Consumption of yogurt has been shown to promote health benefits due to the presence of live bacteria. A number of human studies have demonstrated that yogurt contains viable bacteria, and especially L. bulgaricus, improve the health of the host and thus qualifies as a bona fide probiotic in its own right. In this chapter, we review the literature covering attributes of the yogurt bacterium L. bulgaricus that confirm its probiotic bacterial characteristics

Identification of Homogeneous Areas for Drought Frequency Analysis

Owing to high spatial and temporal rainfall variability, rationale water management decision-making is complex. Hence, it is essential to identify homogeneous areas to assist water management. This paper focusses on separating the study area into homogeneous groups to predict the risk of occurrence of a drought event. The severity-duration-frequency (SDF) curves were developed to determine the relationship between the probability of a drought occurring with a certain severity and frequency at the selected stations in Victoria, Australia. Two techniques namely cluster analysis and modified Andrews curve were used in grouping study area that have similar climate characteristics with respect to risk of occurrence of drought (i.e. rainfall variability). The study area was divided into six clusters and they adequately covered the study area. A mean drought frequency curve was developed for each homogeneous group to determine the probability of vulnerability to a drought event with a certain severity. The advantage of separating stations into homogenous groups based on similar drought characteristics is that it eliminates the necessity to carry out a detailed drought characteristic analysis for any location of interest. The measurable characteristics of this station will determine its best match with the existing cluster groups

Use of Dietary Supplements among Professional Athletes in Saudi Arabia

The objective of this study was to understand the usage patterns of dietary supplements among professional athletes in Saudi Arabia. The survey consisted of sixteen questions divided into four categories: use of supplements, reason for consumption of supplements, personal beliefs about supplements, and behavior. The questionnaires were given to the three teams residing in Riyadh: Al Hilal, Al Nasr, and Al-Shabab. Out of the 105 athletes surveyed, we found that only 98 are currently taking dietary supplements and the mean age and standard deviation were 25.74±2.90. The survey results showed a high percentage of athletes (93.3%; n=98) using different dietary supplements throughout the season, 43.8% (n=43) reported using supplements for performance, and 32.6% (n=32) believed in health benefits as a reason for using dietary supplements. Our results showed that a total of 87 (88.7%), 81 (82.6%), and 51 (52.0%) athletes are consuming sports drinks, vitamin C, and multivitamins, respectively. Meanwhile, those supplements ranking among the least used included omega 6 (18.6%), creatine (16.3%), and Ginkgo biloba (10.2%). A majority of athletes indicated that their use of supplements was for the purpose of improving their health and performance

Energy-Efficient Federated Learning With Resource Allocation for Green IoT Edge Intelligence in B5G

An edge intelligence-aided Internet-of-Things (IoT) network has been proposed to accelerate the response of IoT services by deploying edge intelligence near IoT devices. The transmission of data from IoT devices to the edge nodes leads to large network traffic in the wireless connections. Federated Learning (FL) is proposed to solve the high computational complexity by training the model locally on IoT devices and sharing the model parameters in the edge nodes. This paper focuses on developing an efficient integration of joint edge intelligence nodes depending on investigating an energy-efficient bandwidth allocation, computing Central Processing Unit (CPU) frequency, optimization transmission power, and the desired level of learning accuracy to minimize the energy consumption and satisfy the FL time requirement for all IoT devices. The proposal efficiently optimized the computation frequency allocation and reduced energy consumption in IoT devices by solving the bandwidth optimization problem in closed form. The remaining computational frequency allocation, transmission power allocation, and loss could be resolved with an Alternative Direction Algorithm (ADA) to reduce energy consumption and complexity at every iteration of FL time from IoT devices to edge intelligence nodes. The simulation results indicated that the proposed ADA can adapt the central processing unit frequency and power transmission control to reduce energy consumption at the cost of a small growth of FL time

A Close Proximity 2-Element MIMO Antenna Using Optically Transparent Wired-Metal Mesh and Polyethylene Terephthalate Material

An optically transparent MIMO antenna with close proximity two-element square patch antenna elements has been presented here to achieve forthcoming requirements of compactness, optical transparency and visual aesthetic for 5G wireless communication and Internet of Things (IoT) applications. A simple, thin optically transparent and more innovative decoupling structure with easier to design closely spaced transparent MIMO antenna configuration is proposed, optimized, and analyzed to achieve higher isolation and diversity gain performance even with close proximity of patch antenna elements. Polyethylene terephthalate (PET) material, a thermoplastic polymer resin of the polyester family, is used as a substrate to achieve optical transparency. The wired metal mesh parameters are considered to achieve the required optical transparency, isolation and radiation performance for the MIMO antenna. The performance of the proposed MIMO antenna is also verified through the fabricated prototype

Design and optimization of a transparent and flexible MIMO antenna for compact IoT and 5G applications

This work presents an optically transparent and flexible MIMO antenna that features two square patch elements placed in close proximity, aiming to meet the demands of compactness, flexibility, optical transparency, and visual appeal for IoT applications and future 5G wireless communication. The design includes a simple offset fed configuration to achieve the required isolation and impedance matching. It simplifies the process of creating closely spaced transparent MIMO antenna configurations. By optimizing and analyzing this structure, the antenna achieves better isolation and diversity gain performance, even when the patch elements are positioned very close to each other. To achieve optical transparency and flexibility, the antenna uses thin polyethylene terephthalate (PET) material as a substrate, which is a thermoplastic polymer resin from the polyester family. The wired metal mesh parameters for conducting parts of the MIMO antenna and offset position of the feed are carefully optimized to achieve required optical transparency, isolation, impedance matching and radiation performance without any complex decoupling or impedance matching network