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Shielding devices from electromagnetic waves is important for effective functioning and security. Metals possess very good shielding properties due to their high conductivity. The current article investigates the factors influencing the shielding efficiency of on aluminium sheet/foil and copper nickel (Cu-Ni) conductive fabric. The conductivity, thickness, and amount of preformation influences the efficiency of aluminium and Cu-Ni conductive fabric in mitigating electromagnetic interference (EMI). The experimental data gathered from measuring shielding effectiveness across a spectrum of frequencies (1-18 GHz) were studied to understand the influence of these factors on the overall performance of shielding. The findings from this research enhance our comprehension of the factors impacting EMI shielding efficiency, guiding the development and enhancement of shielding solutions for various electronic applications.

The optical properties of nanoparticle (NP) metals displaying the highest plasmonic response (silver, gold, copper and aluminium) are simulated. Embedding the metal NPs in a dielectric medium provides prevention from agglomeration, increased absorption and protection from environmental effects. Hence, embedding is an effective method to improve the performance of plasmonic-based devices. The NPs of the aforementioned metals were simulated in air, glass and a-Si environment from the ultraviolet to the near-infrared range. Spheres, nanobars and nanoprisms of volume equal to spheres of diameter 50–200 nm were studied in a broad wavelength range of 200–1800 nm. The effect of the material, size, shape and environment was observed quantitatively by analysing the peak shifts of the dipole and higher-order poles. The highest extent of peak shift due to change in size and surrounding environment was for aluminium, followed by silver, gold and copper.

Laser interference lithography (LIL) was used to fabricate gold nanodisk arrays on glass which was studied as surface-enhanced Raman spectroscopy (SERS) substrates. The Raman response of varying array periods (250 nm, 300 nm, 344 nm, 395 nm, and 446 nm) was compared using the chemical rhodamine 6G. The 300-nm period displayed the highest SERS enhancement among the tested LIL substrates. Experimental transmission measurements and their finite element method (FEM) simulations were taken to understand the optical response of the LIL substrates. The 300-nm-period LIL substrate was used to detect urea to confirm its practical use as a SERS substrate. The enhancement factor of the 300-nm-period substrate was 2.3 × 10 6 . Furthermore, the detection limit of urea was 0.05 mM for the optimized substrate. Graphical Abstract

Passenger safety during vehicle collision led to the requirements of improved crashworthiness. Most of the previous work is focused on standalone crashworthy structures having limited load adaptability and modularity. To mitigate these drawbacks, a novel metallic nested tube structure is proposed resulting increased energy absorption efficiency and modularity. The proposed energy absorber has fine as well as coarse step tunability to suit real world requirements. This structure comprises of three deformable structures i.e. Skin, Outer tube and Inner tube. Sensitivity analysis is performed to study the effect of skin thickness, outer tube thickness, inner tube thickness and number of inner tubes on energy absorption. Four types of nested structures namely C-1/C-2/C-3/C-4 are obtained by using 1/3/5/7 inner tubes. Numerically estimated MCF for C-1/C-2/C-3/C-4 are 7.85kN/10kN/13kN/18.16kN respectively. Due to highest MCF, C-4 is found to absorb 231%/181%/140% more energy than C-1/C-2/C-3. Multivariable optimization using L16 Taguchi design led to two variants. NTS 4/4/4/4 , containing maximum thickness of all deformable members and 7 inner tubes, is found to absorb highest energy. Whereas, NTS 1/4/4/4 possessing combination of thinnest skin, thickest inner/outer tubes and 7 inner tubes reflected superior specific energy absorption. Prototypes of both the variants were evaluated experimentally and the results are found consistent with numerical simulation. A material, mass and volume independent comparison revealed that both the variants are superior to most of the nested structures present in existing literature. Modularity, tunability and superior performance make C-4 a suitable candidate for current and future transportation systems.

Shock tube testing is the optimal method to study blast mitigation behaviour of materials in a controlled environment. In the present study, aluminium alloy 6061-T6 sheets of two configurations (solid and perforated) and two thicknesses (3 and 2 mm) were compared. A compressed gas driven shock tube was selected for the experimental testing of the sheets. Numerical simulation of the shock loading impact on the sheets was performed using finite element method, and the input of the shock loading condition was acquired from experimental data. The simulation results were in close agreement with the experimentally tested sheets. The stress, strain, velocity and energy response of the sheets was studied using the numerical simulation of the shock wave impact. It was observed that the thickness and perforations had a significant effect on the structural and energy response of the sheets. The 2 mm thick perforated sheet experienced complete fracture and absorbed the highest energy. Graphical Abstract

Critical cases of COVID-19 require respiratory support provided primarily by mechanical ventilators. But, as per the current trend, about 15% of the cases require hospitalization and less than 5% cases are critical. Due to the massive number of COVID-19 cases all over the world, the ventilator requirement is increasing, and these traditional ventilators are quite expensive and are occupied for the critical cases, thus available in limited numbers. In this regard, BiPAP (Bilevel Positive Airway Pressure) ventilation support can be used for the less critical cases where patients do not require intubation by specialized staff and also minimizing the risk of infection during the procedure. The current article aims to deliver a design of an inexpensive BiPAP with an infection-free exhaust. BiPAP is a mode of ventilation which maintains positive pressure for air intake, and a low or zero pressure is created for expiration. The BiPAP suggested in the current article uses an air blower connected to an Arduino via a speed controller, the level of pressure and breathing rate are programmed in the Arduino, thus, the blower functions in BiPAP mode. The 3D printed mask proposed here comprises of a unique design for the intake and exhalation of air; and comprises of two sizes to fit all adults while avoiding any leakage. The design suggested is further tweaked for emergency use to support up to four patients using a single BiPAP. The mass production of the same would cost approx. INR 6500 or 85 USD.

The most abundant and easily available energy source is sunlight. Solar cells are able to convert solar energy to electrical energy; the quantity of electrical energy produced can be increased by improving the light trapping ability of solar cells. Surface texturing is an excellent method to achieve light trapping at a reasonable cost. Mono-crystalline solar cells have dominated the solar cell market for decades, and still have 90% of the market share. Multi-crystalline solar cells have lower efficiency, but have gained attention due to their low fabrication cost. Lasers already play a vital role in solar cell production due to their versatility and low maintenance compared to chemical techniques. Laser assisted surface texturing can be applied to both mono and multi-crystalline silicon solar cells, which is not practical through conventional etching techniques. In the current article, the laser assisted surface texturing of solar cells with features in micro- and nano-scale are presented. Also, methods to improve silicon-based solar cells and the principles of optical enhancement via surface texturing are studied in detail.

Thin film continuity using different fabrication processes is crucial in deciding its plasmonic response. The surface plasmon (SPR) response of gold films of various thicknesses deposited with and without a quartz base oscillating at 6 MHz was studied. The presence of the oscillating piezoelectric base resulted in a decrease in the surface roughness of the gold film. The 40 nm thick film displayed the best SPR response among the various thicknesses tested. The 40 nm film deposited piezoelectrically had a Q factor increase and an increased slope of the angle and wavelength dependent resonance curve as compared to 40 nm thick film not deposited piezoelectrically.

Increasing temperature is a key component of global climate change, affecting crop growth and productivity worldwide. Wheat is a major cereal crop grown in various parts of the globe, which is affected severely by heat stress. The morphological parameters affected include germination, seedling establishment, source-sink activity, leaf area, shoot and root growth. The physiological parameters such as photosynthesis, respiration, leaf senescence, water and nutrient relation are also affected by heat. At the cellular level, heat stress leads to the generation of reactive oxygen species that disrupt the membrane system of thylakoid, chloroplast and plasma membrane. The deactivation of the photosystem, reduction in photosynthesis and inactivation of rubisco affect the production of photoassimilates and their allocation. This ultimately affects anthesis, grain filling, size, number and maturity of wheat grains, which hamper crop productivity. The interplay of various systems comprising antioxidants and hormones plays a crucial role in imparting heat stress tolerance in wheat. Thus, implementation of various omics technologies could foster in-depth insights on heat stress effects, eventually devising heat stress mitigation strategies by conventional and modern breeding to develop heat-tolerant wheat varieties. This review provides an integrative view of heat stress responses in wheat and also discusses approaches to develop heat-tolerant wheat varieties.