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Compact low specific absorption rate (SAR) hexa-band planar inverted-F antenna (PIFA) with independent resonant frequency control is presented in this study. Two trapezoidal shaped slots are etched on the coplanar waveguide (CPW)-fed PIFA-radiating plate to create two independent resonant frequencies as well as the fundamental CPW-fed PIFA itself. Three coupled slots are added within the ground plane to create additional three independent resonant frequencies with slight effect on the other resonant frequencies. Multiband (dual, tri, quad, penta and hexa) band capabilities with bandwidth enhancement and acceptable SAR values are realised for different wireless communication applications. The SAR of human head is investigated by using Computer Simulation Technology (CST) 2012 Microwave Studio Hugo Voxel Model. The proposed antennas are fabricated and there is a good agreement between measured and simulated results.

In this paper, a wearable antenna array based on a 9 × 3 artificial magnetic conductor (AMC) array is proposed with the characteristics of compact, low profile, low specific absorption rate (SAR), high front-to-back ratio (FBR) and high gain for wireless body area network (WBAN) bands. The proposed wearable antenna consists of a four-element array and an AMC array. The size of antenna array loaded AMC is 137.7 × 45.9 mm 2 . The dielectric substrate of the antenna and the AMC structure are made of 0.1 mm liquid crystal polymer material, which is flexible and low profiled. The antenna operates from 5.62 to 6 GHz after the AMC structure is loaded. The gain increases by 3.23 dB, reaching 12.03 dB at 5.8 GHz. And the FBR value is raised by 26.04 dB. The highest SAR value of the simulated antenna on the human model is 0.0496 W/kg, far less than the US federal or EU requirements. After constructing and testing the antenna, the outcomes of the tests agreed with the results of the simulation. The flexible antenna array with AMC structure has good prospect in WBAN applications.

This paper presents a compact, low-cost dual-band antenna design with low specific absorption rate (SAR) for Wireless Body Area Networks (WBAN) and Industrial, Scientific, and Medical (ISM) applications. The proposed antenna operates at 2.4 GHz with linear polarization and 5.8 GHz with circular polarization, fabricated on a 1.52 mm thick RF35 dielectric substrate (28 40 mm). The design features a coplanar waveguide (CPW) feed integrated with substrate-integrated waveguide (SIW) technology to enhance bandwidth and return loss characteristics.The antenna has broad bandwidths of 0.5 GHz with a 2.4 GHz center and 1 GHz with a 5.8 GHz center. To mitigate back radiation and reduce SAR, a 4 4 electromagnetic bandgap (EBG) structure was incorporated, resulting in significant performance improvements. The EBG implementation increased the maximum gain from 3.66 to 8.56 dB at 2.4 GHz and from 3.97 to 10 dB at 5.8 GHz. Additionally, SAR values decreased from 7.34 to 1.62 W/kg for 1 g of tissue at 2.4 GHz and from 2.18 to 0.91 W/kg at 5.8 GHz.Prototype measurements confirm simulation results, demonstrating the antenna’s suitability for WBAN and wearable ISM applications, including sensor networks and Wi-Fi devices. The design offers advantages of independent band tuning, circular polarization at the higher frequencies, and compliance with safety standards for human exposure to electromagnetic fields.

The increasing demand for wireless communication has emphasized the need for multiband antennas. This study presents a novel design for a multiband antenna with reduced specific absorption rate (SAR), high gain, and improved front-to-back ratio (FBR) achieved through the integration with a 4 × 4 artificial magnetic conductor (AMC) surface. The proposed antenna covers a wide range of wireless frequency bands, including Industrial, Scientific, and Medical, Wireless Local Area Network, Worldwide Interoperability for Microwave Access, Wi-Fi 6E, and 7, with resonating frequencies at 2.4, 3.2, 5.5, 7.5, and 10 GHz. The AMC unit cell creates four zero-degree reflection phases with double negative properties at 2.5, 3.8, 5.5, and 7.5 GHz. The compact design measures 0.23λ 0  × 0.296λ 0  × 0.0128λ 0 and placed 0.104λ 0 above an AMC surface of size 0.512λ 0  × 0.512λ 0  × 0.1296λ 0 . This structure enhances the gain by up to 8.55dBi at 6.01 GHz. The proposed antenna has −10 dB impedance bandwidth for these corresponding frequencies viz 2.34–2.43 GHz (3.77%), 2.81–3.83 GHz (30.72%), 4.82–6.21 GHz (25.20%), 7–7.65 GHz (8.87%), and 8.06–10.31 GHz (24.5%). An overall average percentage reduction value of SAR taken at these frequencies has been found to be 96.11% with AMC structure. The antenna sample was successfully fabricated, and the experimental results have been found to match well with the simulation results. This integrated design offers a promising solution for wearable off-body communication devices.

In this study, textured vegetable protein (TVP) based on soy protein isolate, wheat gluten, and corn starch was prepared at a 5:3:2 (w/w) ratio using a low-moisture extrusion process. To evaluate the effects of extrusion parameters, die temperature and screw rotation speed, on the properties of TVP, these two parameters were manipulated at a constant barrel temperature and moisture content. The results indicated that increasing the die temperature increased the expansion ratio while decreasing the density of the extrudates. Simultaneously, increasing the screw rotation speed clearly increased the specific mechanical energy of the TVP. Furthermore, mathematical modelling suggested that the expansion ratio increases exponentially to the die temperature. However, extreme process conditions bring about a decrease in water absorption capacity and expansion ratio, as well as undesirable texture and microstructure. The results suggested that the properties of SPI-based TVP are directly influenced by the extrusion process parameters, screw speed and die temperature.

Background Recent WHO-commissioned systematic reviews have concluded with “high certainty” that exposure to radiofrequency electromagnetic fields (RF-EMF) increases cancer risk and reduces male fertility in experimental animals. Methods We performed benchmark dose (BMD) analyses on experimental cancer data to estimate exposure levels associated with cancer risk of 1 × 10 –5 (1 in 100,000). Due to the lack of an established non-linear mode of action for RF-EMF-induced tumor responses, we utilized linear low-dose extrapolation from 1% BMD values. In addition, we applied traditional uncertainty factors to the reported linear potency value of 0.03 per W/kg for male reproductive toxicity to derive health-protective exposure limits. Results The derived dose per hour (expressed as the specific absorption rate, SAR) at 1 × 10 –5 cancer risk ranges from about 0.8 to 5 mW/kg. It should be noted that cancer risk increases with increasing time of exposure to RF-EMF. For protection of male fertility due to exposure to RF-EMF, the estimated SAR exposure limit was 3.3 to 10 mW/kg. These health protective whole-body exposure values are significantly lower than the current whole-body exposure limit value of 0.08 W/kg (80 mW/kg) established by ICNIRP and the FCC for the general public. Conclusions For the general public, current regulatory limits to RF-EMF are 15- to 900-fold higher than our estimates of exposure levels associated with cancer risk of 1 × 10 –5 (depending on the duration of daily exposure), and 8- to 24-fold higher than levels that are protective of male reproductive health. Thus, we strongly recommend an independent re-evaluation of RF-EMF exposure limits, integrating scientific data accumulated over the past 30 years and applying rigorous health-protective methodologies.

In this article a low profile asymmetrical slotted Ultra-Wide Band (UWB) antenna is proposed for Wireless Body Area Networks (WBANs) applications. The antenna was fabricated using Printed Circuit Boards (PCBs). An improved radiation pattern was obtained with an optimized patch shape of the antenna that broadens the bandwidth and lowers the antenna’s profile. The proposed antenna is simulated in HFSS and CST Simulator, and the proposed antenna is fabricated on FR4 substrate with the reduced ground plane. In frequency ranges from 2.50 to 10.97 GHz simulation as well as measured results show that the reflection coefficient (S11) of the antenna is below − 10 dB and increased impedance bandwidth of 126%. The proposed antenna has desired radiation pattern and gain for wearable application. The wearable performance of proposed antenna on chest, leg, and the arms of the human body is analyzed with Specific Absorption Rate (SAR). The maximum value of the SAR is 0.785 W/Kg which is less than threshold value of 1.6 W/kg. The time-domain behavior of proposed antenna is investigated with the time domain parameters such as Group delay, Fidelity factor and Mean realized gain. The time domain results are evident for the proposed antenna is capable of pulse signal transmission and reception.

Filling layer self-compacting concrete (FLSCC) is a key material in newly-built China Rail Track System (CRTS), which is commonly subjected to cyclic dynamic load from high-speed train and various ambient temperature during service. In this paper, a series of indoor simulating experiments was conducted to investigate the impact resistance of FLSCC suffering from cyclic flexural load and different temperature conditions with a Φ75 mm split Hopkinson pressure bar (SHPB). The dynamic increase factors were introduced to evaluate the strain rate effect on various mechanical properties of FLSCC and the corresponding mechanisms were explained. Results show that the dynamic increase factor of compressive strength ( DIF c ) and peak strain ( DIF ε ) of FLSCC increase linearly with logarithm of strain rate, while specific energy absorption increases exponentially with strain rate. The impact resistance of FLSCC is greatly influenced by cyclic flexural load and low temperature. The strain rate sensitivity of compressive strength of FLSCC at minus temperature (−20°C) is weaker than that at normal temperature (20°C) and after freeze-cyclic load coupling action the sensitivity decreases further. Similar tendencies were also observed in peak strain and specific energy absorption.

In this paper, a new low-Specific Absorption Rate (SAR) antenna is proposed for the sake of safe communication in all situations. The proposed antenna involves a Microstrip patch antenna and a metallic casing loop which leads to SAR reduction. The structure operates at 0.9 GHz and 2.4 GHz which produces 0.52 W/kg and 0.25 W/kg SAR value on the human head, respectively. Then, in order to guarantee the antenna safety feature, the experiments are carried out when the human wear an earring. The impact of metallic earrings in different sizes on SAR distribution is investigated. Also, the antenna orientation and rotation effect is considered in detail. It is concluded that the change of Antenna position or use of metallic earrings makes an extremely significant impact on SAR value. But, the results of the presented antenna demonstrate that the produced SAR value in all positions, do not exceed the safe rate. It makes the antenna a suitable candidate for employing in most telecommunication applications.

The aim of this study was to describe, for the first time, the embryogenesis and larval growth of the Paraitinga Brycon nattereri Günther, 1864 reared in captivity. After artificial fertilization, eggs were incubated at constant temperature (~19°C) and collected every 15 min during the first 3 h and then every 3 h until hatching. Five larvae were collected daily over 15 days for evaluation of the length, yolk sac volume and specific growth rate. The following stages of embryonic development were identified: zygote, cleavage, gastrula, segmentation and larval. The hatching occurred after 50–54 h, with larvae poorly developed and fully depigmented, devoid of mouth and swimming capacity, presenting 6.32 mm total length and 3.64 mm3 yolk sac volume. The mouth opening was observed between days 3–4 after hatching. The yolk sac absorption was slow during the first 3 days, increasing sharply after this period, being completed on the day 11. During this period there was a decrease in the larval growth rate. After yolk sac absorption, an increase in the growth rate was observed that coincided with the start of exogenous feeding. Cannibalism was not observed during the 15 days of evaluation. The initial development of B. nattereri was slow and poorly developed larvae in relation to other Brycon species, certainly due to the lower temperature required for egg incubation and larval rearing. Other studies are needed in order to develop techniques to improve the methods of incubating eggs and feeding larvae.