Search Results (10)

Essential oils (EOs) are effective repellents and eco-friendly alternatives. We tested single and combination EOs of fennel and anise for repellency and stability against houseflies. All treatments were stored at 27 °C for up to 360 days. Efficacies were compared against α-cypermethrin as a reference. Safety bioassay used on two representative non-target species (guppies and earthworms) confirmed safety. The strongest repellency and stability, 100% repellency and RC₅₀ of 0.4 mL/m³ on day 1, was achieved by a fennel + anise EO combination (1:1). After 360 days, these combinations remained effective (95% repellency), and RC₅₀ = 0.8 mL/m³. The EO combinations were more effective than all single EOs and α-cypermethrin at all times, showing strong synergy with a synergistic repellent index of 2.4 to 3.3. This fennel + anise EO combination was more than 24 times more effective as a repellent than α-cypermethrin. Morphological damage included damaged antennae with twisted flagella and abnormal aristae. All single and combination EOs were not toxic to the non-targets and could be considered safe, whereas α-cypermethrin was highly toxic to them. Thus, the fennel + anise EO combination has great potential to be developed as a safe, natural repellent for managing housefly populations. Full article

The tomato leafminer, Tuta absoluta (Lepidoptera: Gelechiidae), is a highly destructive invasive pest targeting Solanaceae crops. Its olfactory system plays a crucial role in host location, mate finding, and other behavioral activities. However, there is a notable gap in the literature regarding the characterization of its chemosensory genes. In this study, we conducted a genome-wide identification of 58 odorant receptors (ORs) of T. absoluta. The identified ORs exhibit coding sequence (CDS) lengths ranging from 1062 bp to 1419 bp, encoding proteins of 354 to 473 amino acids. Gene structure analysis showed that the majority of these ORs consist of five, seven, eight, or nine exons, collectively representing 67% of the total ORs identified. Through chromosomal mapping, we identified several tandemly duplicate genes, including TabsOR12a, TabsOR12b, TabsOR12c, TabsOR21a, TabsOR21b, TabsOR34a, TabsOR34b, TabsOR34c, TabsOR62a, and TabsOR62b. The phylogenetic analysis indicated that six TabsORs were clustered within the lepidopteran sex pheromone receptor clade, while an expansion clade containing ten TabsORs resulted from tandem duplication events. Additionally, five TabsORs were classified into a specific OR clade in T. absoluta. Furthermore, through RNA-Seq and RT-qPCR analyses, we identified five TabsORs (TabsOR21a, TabsOR26a, TabsOR34a, TabsOR34c, and TabsOR36) exhibiting female-antennae-biased expression. Our study provides a valuable foundation to further investigations into the molecular and ecological functions of TabsORs, particularly in relation to oviposition behavior. These findings provide foundational data for the future exploration of the functions of female-biased expression OR genes in T. absoluta, thereby facilitating the further development of eco-friendly attract-and-kill techniques for the prevention and control of T. absoluta. Full article

Developers of electronics for the Internet of Things are considering nonstandard substrate materials like recyclable, low-cost, and eco-friendly cardboard paper. From this perspective, this article reviews the design and experimental results of a 2D-rectenna for scavenging radio-frequency energy at 2.45 GHz on various cardboard paper substrates for both the antenna and rectifier. Four types of recycled cardboard material, each with different thicknesses, air gaps, and surface roughness, are selected for characterization. A linearly polarized rectangular microstrip patch antenna with microstrip transmission feeding is adopted for ease of fabrication. At 2.45 GHz, the antenna has a simulated and measured global gain of 2.98 dB and 2.53 dB, respectively, on a 2.2 mm thick cardboard material. The rectifying element consists of a voltage-doubler configuration connected through a T-matching network to the antenna. At low RF input power (−10 dBm), the maximum available DC output power is experimentally evaluated at 1.73 μW, 7.5 μW, and 8.5 μW for HSMS-2860, HSMS-2850, and SMS7306-079L diodes, respectively. The respective rectifiers with diodes SMS7306-079L, HSMS-2850, and HSMS-2860 exhibit optimal load values of 2 kΩ, 2.6 kΩ, and 8 kΩ. The rectifier designed using the SMS7306-079L diode experimentally reaches a maximum power conversion efficiency (PCE) of 14.2% at −5 dBm input power when the optimal load value is 1.5 kΩ. Full article

The development of e-textiles necessitates the creation of highly conductive inks that are compatible with precise inkjet printing, which remains a key challenge. This work presents an innovative, syringe-based method to optimize a novel bio-sourced silver ink for inkjet printing on textiles. We investigate the relationships between inks’ composition, rheological properties, and printing behavior, ultimately assessing the electrical performance of the fabricated circuits. Using Na–alginate and polyethylene glycol (PEG) as the suspension matrix, we demonstrate their viscosity depends on the component ratios. Rheological control of the silver nanoparticle-laden ink has become paramount for uniform printing on textiles. A specific formulation (3 wt.% AgNPs, 20 wt.% Na–alginate, 40 wt.% PEG, and 40 wt.% solvent) exhibits the optimal rheology, enabling the printing of 0.1 mm thick conductive lines with a low resistivity (8 × 10⁻³ Ω/cm). Our findings pave the way for designing eco-friendly ink formulations that are suitable for inkjet printing flexible antennas and other electronic circuits onto textiles, opening up exciting possibilities for the next generation of E-textiles. Full article

The Korean National Space Council recently released “Mars Exploration 2045” as part of its future strategic plan. The operations for a Mars explorer can be defined based on domestically available capabilities, such as ground operations, launch, in-space transport and deep space link. Accordingly, all of our exploration scenarios start from the Naro space center, and the pathway to Mars is optimized using an objective function that minimizes the required ∆V. In addition, the entire phase of Mars orbit insertion should remain in contact with our deep space antennas, a measure that is imposed as an operational constraint. In this study, a pattern search method is adopted, as it can handle a nonlinear problem without relying on the derivatives of the objective function, and optimal trajectories are generated on a daily basis for a 15-day launch period. The robustness of this direct search method is confirmed by consistently converged solutions showing, in particular, that the ascending departure requires slightly less ∆V than the descending departure on the order of 10 m/s. Subsequently, mass estimates are made for a Mars orbiter and a kick stage to determine if the desired ∆V is achievable with our eco-friendly in-space propulsion system when launched from our indigenous launch vehicle, KSLV-II. Full article

The volatiles extracted by the dynamic headspace collection system from the undamaged and conspecific damaged Cucurbita maxima were analyzed by Gas chromatography–mass spectrometry (GC-MS). The olfactory responses of antennal chemosensilla by male and female A. foveicollis towards the plant volatiles were studied by electroantennography (EAG), while the behavioral responses were analyzed by olfactometer bioassay under laboratory conditions. Scanning electron microscopic study revealed the predominance of antennal olfactory sensilla of seven different types with four types of mechanosensilla. The antennae are sexually dimorphic, with differences in density of the chemosensillae present in the apical band region of segment IX, called the circumferential band, being higher in the females. Female antennae showed maximum peak amplitudes for 2-methyl phenol (at 10 mg/mL), followed by 1,4, dimethoxybenzene (at 5 mg/mL), while male antennae showed maximum amplitudes for heneicosane (at 5 mg/mL). Y-tube bioassays revealed maximum attractiveness towards 1,4, dimethoxy benzene that decreased progressively across heneicosane, pentacosane, tetradecane, ethyl benzene, D-limonene, nonadecane, eicosane, nonanal, decanal, α-pinene, phytol and benzaldehyde in females. However, male species were more responsive towards heneicosane, followed by 1,4 dimethoxybenzene, while the responses to pentacosane and tetradecane were equal, followed by equal responses to decanal, ethyl benzene and nonadecane, and thereafter, a progressively reducing response was observed towards α-pinene, eicosane, nonanal, D-limonene, phytol and benzaldehyde. The study assists in understanding the role of olfaction by A. foveicollis in the host plant Cucurbita maxima by listing compounds that act as potential kairomones for the beetle, and can be expected to facilitate development of an eco–friendly trap and/or by attracting the natural enemies for control of the pest. Full article

The design, simulation, realization, and measurement of an ultra-wideband (UWB) antenna on a polymeric substrate have been realized. The UWB antenna was prepared using conventional technology, such as copper etching; inkjet printing, which is regarded as a modern and progressive nano-technology; and polymer thick-film technology in the context of screen-printing technology. The thick-film technology-based UWB antenna has a bandwidth of 3.8 GHz, with a central frequency of 9 GHz, and a frequency range of 6.6 to 10.4 GHz. In addition to a comparison of the technologies described, the results show that the mesh of the screens has a significant impact on the quality of the UWB antenna when utilizing polymeric screen-printing pastes. Last but not least, the eco-friendly combination of polyimide substrate and graphene-based screen-printing paste is thoroughly detailed. From 5 to 9.42 GHz, the graphene-based UWB antenna achieved a bandwidth of 4.42 GHz. The designed and realized UWB antenna well exceeds the Federal Communications Commission’s (FCC) standards for UWB antenna definition. The modification of the energy surface of the polyimide substrate by plasma treatment is also explained in this paper, in addition to the many types of screen-printing pastes and technologies. According to the findings, plasma treatment improved the bandwidth of UWB antennas to 5.45 GHz, and the combination of plasma treatment with graphene provides a suitable replacement for traditional etching technologies. The characteristics of graphene-based pastes can also be altered by plasma treatment in terms of their usability on flexible substrates. Full article

Upcoming 5th-generation (5G) systems incorporate physical objects (referred to as things), which sense the presence of components such as gears, gadgets, and sensors. They may transmit many kinds of states in the smart city context, such as new deals at malls, safe distances on roads, patient heart rhythms (especially in hospitals), and logistic control at aerodromes and seaports around the world. These serve to form the so-called future internet of things (IoT). From this futuristic perspective, everything should have its own identity. In this context, radio frequency identification (RFID) plays a specific role, which provides wireless communications in a secure manner. Passive RFID tags carry out work using the energy harvested among massive systems. RFID has been habitually realized as a prerequisite for IoT, the combination of which is called IoT RFID (I-RFID). For the current scenario, such tags should be productive, low-profile, compact, easily mountable, and have eco-friendly features. The presently available tags are not cost-effective and have not been proven as green tags for environmentally friendly IoT in 5G systems nor are they suitable for long-range communications in 5G systems. The proposed I-RFID tag uses the meandering angle technique (MAT) to construct a design that satisfies the features of a lower-cost printed antenna over the worldwide UHF RFID band standard (860–960 MHz). In our research, tag MAT antennas are fabricated on paper-based Korsnäs by screen- and flexo-printing, which have lowest simulated effective outcomes with dielectric variation due to humidity and have a plausible read range (RR) for European (EU; 866–868 MHz) and North American (NA; 902–928 MHz) UHF band standards. The I-RFID tag size is reduced by 36% to 38% w.r.t. a previously published case, the tag gain has been improved by 23.6% to 33.12%, and its read range has been enhanced by 50.9% and 59.6% for EU and NA UHF bands, respectively. It provides impressive performance on some platforms (e.g., plastic, paper, and glass), thereby providing a new state-of-the-art I-RFID tag with better qualities in 5G systems. Full article

An ultrathin, compact ecofriendly antenna suitable for IoT applications around 2.45 GHz is achieved as a result of exploring the use of Tencel fabric for the antenna’s design. The botanical ecofriendly Tencel is electromagnetically characterized, in terms of relative dielectric permittivity and loss tangent, in the target IoT frequency band. To explore the suitability of the Tencel, a comparison is conducted with conventionally used RO3003, with similar relative dielectric permittivity, regarding the antenna dimensions and performance. In addition, the antenna robustness under bent conditions is also analyzed by measurement. To assess the relevance of this contribution, the ultrathin ecofriendly Tencel-based antenna is compared with recently published antennas for IoT in the same band and also, with commercial half-wave dipole by performing a range test on a ZigBee-based IoT testbed. Full article

This paper presents a miniaturized Doppler radar that can be used as a motion sensor for low-cost Internet of things (IoT) applications. For the first time, a radar front-end and its antenna are integrated on a multilayer cellulose-based substrate, built-up by alternating paper, glue and metal layers. The circuit exploits a distributed microstrip structure that is realized using a copper adhesive laminate, so as to obtain a low-loss conductor. The radar operates at 24 GHz and transmits 5 mW of power. The antenna has a gain of 7.4 dBi and features a half power beam-width of 48 degrees. The sensor, that is just the size of a stamp, is able to detect the movement of a walking person up to 10 m in distance, while a minimum speed of 50 mm/s up to 3 m is clearly measured. Beyond this specific result, the present paper demonstrates that the attractive features of cellulose, including ultra-low cost and eco-friendliness (i.e., recyclability and biodegradability), can even be exploited for the realization of future high-frequency hardware. This opens opens the door to the implementation on cellulose of devices and systems which make up the “sensing layer” at the base of the IoT ecosystem. Full article