Nano-structure based metamaterial absorbers have been getting enormous interest owing to their widespread applications in solar cells, thermal emitters and integrated photonic devices. This paper presents a novel and ultrathin broadband metamaterial absorber comprised of a hexagonal nano-ring shaped fractal structure. The designed fractal metamaterial absorber (FMA) is composed of a three-layer device having a metal-insulator-metal (MIM) configuration. Based on the numerical simulations, the proposed FMA manifests more than 97% absorptivity for the operating wavelength from 820 to 2520 nm. However, it shows above 80% absorption value for the entire operating wavelength from 200 to 4000 nm. To predict the angular stability of this broadband absorption device, the absorptivity was investigated under different oblique incident angles of the exciting wave by considering both transverse electric (TE)- and transverse magnetic (TM)-polarization. Further, multiple reflection theory was employed to calculate the absorption value of FMA, and it shows appreciable agreement with the simulation results. It is also anticipated that this kind of FMA has not been investigated yet with these ultrabroadband absorption characteristics. Large operating bandwidth, angular robustness, ultra-compact thickness and inclusion of low-cost and temperature-endurable nickel metal (Ni) make this nanostructure-based absorber an attractive candidate for solar photovoltaics, thermal emission, and infrared spectroscopic applications.

Sustainable agriculture is a pivotal driver of a nation’s economic growth, especially considering the challenge of providing food for the world’s expanding population. Agriculture remains a cornerstone of many nations’ economies, so the need for intelligent, sustainable farming practices has never been greater. Agricultural industries worldwide require sophisticated systems that empower farmers to manage their crops efficiently, reduce water wastage, and optimize yield quality. Yearly, substantial crop losses occur due to unpredictable environmental changes, with improper irrigation practices being a leading cause. In this paper, we introduce an innovative irrigation time control system for smart farming. This system leverages fuzzy logic to regulate the timing of irrigation in cotton crop fields, effectively curbing water wastage while ensuring that crops receive neither too little nor too much water. Additionally, our system addresses a common agricultural challenge: whitefly infestations. Users can adjust climatic parameters, such as temperature and humidity, through our system, which minimizes both whitefly populations and water consumption. We have developed a portable measurement technology that includes air humidity sensors, temperature sensors, and rain sensors. These sensors interface with an Arduino platform, allowing real-time climate data collection. This collected climate data is then sent to the fuzzy logic control system, which dynamically adjusts irrigation timing in response to changing environmental conditions. Our system incorporates an algorithm that generates highly effective (IF-THEN) fuzzy logic rules, significantly improving irrigation efficiency by reducing overall irrigation duration. By automating the irrigation process and precisely delivering the right amount of water, our system eliminates the need for human intervention, rendering the agricultural system more dependable in achieving successful crop yields. Water supply commences when the environmental conditions reach specific thresholds and halts when the requisite climate conditions are met, maintaining an optimal environment for crop growth.

This work presents the fabrication and investigation of thermoelectric cells based on composite of carbon nanotubes (CNT) and silicone adhesive. The composite contains CNT and silicon adhesive 1∶1 by weight. The current-voltage characteristics and dependences of voltage, current and Seebeck coefficient on the temperature gradient of cell were studied. It was observed that with increase in temperature gradient the open circuit voltage, short circuit current and the Seebeck coefficient of the cells increase. Approximately 7 times increase in temperature gradient increases the open circuit voltage and short circuit current up to 40 and 5 times, respectively. The simulation of experimental results is also carried out; the simulated results are well matched with experimental results.