Plant Based Biosynthesis of Copper Nanoparticles and its Efficacy on Seed Viability and Seedling Growth in Peanut (Arachis hypogaea Linn.)

Nano-fertilizers can easily adsorb into the plant and can increase the reactive points in the plant and hence are treated as an efficient alternative to the conventional fertilizers. Based on this, the present study was intended to synthesize copper nanoparticles (CuNPs) using aqueous root extract of Schrebera swietenioides Roxb. as green reducing agent. The synthesized nanoparticles were studied for its effectiveness on enhancement of seed germination and plant growth promotion on peanut (Arachis hypogaea Linn.). The formation of nanoparticles was confirmed by observing colour change in the reaction mixture, which shows characteristic absorption maxima at 340 nm. The SEM and TEM analysis confirmed that the nanoparticles were in monodispersed with spherical to irregular shape with an average particle size of 35 nm. The EDX analysis confirmed that the nanoparticles contain 82.5% copper metal. The synthesized nanoparticles were applied for its seed germination enhancement activity on peanut seeds and results confirms that the nanoparticles were significantly enhances the germination of peanut seeds with decrease in mean germination time. The peanut plant growth also enhances when compared with metal solution treatment and untreated plants. The root length of CuNPs treated plants was observed to be 9.27 ± 0.15 cm, which is significantly more than the untreated (6.40 ± 0.10 cm) as well as treated copper metal (7.13 ± 0.25 cm) plants. The shoot length of 19.13 ± 0.20 cm was observed for nano-treated plants and is greatly enhanced than the untreated (10.30 ± 0.20 cm) and treated copper metal (11.27 ± 0.25 cm) plants. The protease activity on day 5 of the germination study was found to be 0.904 ± 0.004, 0.133 ± 0.002 and 0.095 ± 0.002 units/mL, respectively for the peanut seeds treated with CuNPs, copper metal solution and untreated conditions. The catalase activity at 5th day of seed germination studies the activity was observed to be 45.177 ± 0.192, 23.691 ± 0.074 and 18.331 ± 0.209 units/min/g, respectively for CuNPs treated, copper sulphate treated and untreated pea nut seeds. The water update of the nano treated seeds was observed to be very high along with high quantity of photosynthetic pigments when compared with the other treatments in the study. Based on the results achieved, it can be confirmed that the nano-treatment enhances the seed germination and plant growth promotion on peanut seeds.

Design of a Planar Array of Low Profile Horns at 28 GHz

A planar array of low profile horns fed by a transverse slotted waveguide array in the low millimeter-wave regime (28 GHz) is presented. The array of transverse slots cannot be directly used as antenna as it has grating lobes due to the fact that slot elements must be spaced a guided wavelength. However, these slots can be transformed into low profile horns that with their radiation patterns attenuate the grating lobes. To this aim, low profile horns with less than 0.6λ0 height were designed. The horns include a couple of chips that contribute to further reduce the grating lobes especially in the H-plane. The good performance of the designed array was demonstrated by both simulations and experiments performed on a manufactured prototype. A 5 × 5 array was designed that has a measured realized gain of 26.6 dBi with a bandwidth below 2%, still useful for some applications such as some radar systems. The total electrical size of the array is 6.63λ0× 6.63λ0. The radiation efficiency is very high and the aperture efficiency is above 80%. This all-metal solution is advantageous for millimeter-wave applications where losses sustained by dielectric materials become severe and it can be easily scaled to higher frequencies.

Kinetics and Equilibrium Studies for the Removal of Mn and Fe from Binary Metal Solution Systems Using a Romanian Thermally Activated Natural Zeolite

In the present study, the sorption behavior of iron (Fe) and manganese (Mn) from a binary metal solution system onto thermally activated natural zeolite was studied. Batch adsorption experiments were carried out to investigate the effects of zeolite quantity, particle size, and activation temperature. Equilibrium studies were carried out to evaluate the adsorption capacity of the thermally activated natural zeolite. The obtained results showed that the thermally activated natural zeolite favored the removal of Fe over Mn, due to competition between them. Elemental analysis of the activated zeolite samples obtained by energy-dispersive X-ray analysis (EDX) indicated a Si/Al ratio >4, which is specific for clinoptilolite-type zeolite. The removal of Fe and Mn was best described by the Langmuir model, indicating the formation of a monolayer on the surface of the activated natural zeolite. The kinetic results revealed that the experimental data were best fitted by the pseudo-second-order model for both metals. The results suggest that a new natural zeolite from Rupea quarry, Brașov County, Romania could be used as a potential adsorbent for removal of Fe and Mn from binary metal solution systems, addressing the lack of information about this material from this region.