Orthogonal Printed Microstrip Antenna Arrays for 5G Millimeter-Wave Applications

This article presents the design of a planar MIMO (Multiple Inputs Multiple Outputs) antenna comprised of two sets orthogonally placed 1 × 12 linear antenna arrays for 5G millimeter wave (mmWave) applications. The arrays are made of probe-fed microstrip patch antenna elements on a 90 × 160 mm2 Rogers RT/Duroid 5880 grounded dielectric substrate. The antenna demonstrates S11 = −10 dB impedance bandwidth in the following 5G frequency band: 24.25–27.50 GHz. The scattering parameters of the antenna were computed by electromagnetic simulation tools, Ansys HFSS and CST Microwave Studio, and were further verified by the measured results of a fabricated prototype. To achieve a gain of 12 dBi or better over a scanning range of +/−45° from broadside, the Dolph-Tschebyscheff excitation weighting and optimum spacing are used. Different antenna parameters, such as correlation coefficient, port isolation, and 2D and 3D radiation patterns, are investigated to determine the effectiveness of this antenna for MIMO operation, which will be very useful for mmWave cellphone applications in 5G bands.

Stress Distribution and Optimum Spacing Determination of Double-Withdrawal-Channel Surrounding Rocks: A Case Study of Chinese Coal Mine

In this study, the 31113 fully mechanised working face in the Lijiahao Coal Mine was selected as the project background. The failure characteristics and optimum spacing of a double-withdrawal-channel surrounding rock were extensively investigated through field measurements, theoretical analysis, and numerical simulations. The following results were obtained. The loading influence range of the working face was fixed. Under the influence of mining, the stress distribution variation in the double-withdrawal channels with spacing and the influence of stress distribution on the surrounding rock stability of the withdrawal channels were determined. The optimum distance between the double-withdrawal channels to achieve the stability of the surrounding rock was at least 25 m, and engineering measures are required to limit the mining height in the final mining stage. The rationality of the main and auxiliary withdrawal channel spacing of 25 m and measures to limit the mining height in the final stage were demonstrated. The findings of this study provide a valuable reference for constructing the layout of withdrawal channels in the adjacent working faces of the same mining area.

RESPONSE OF OKRA [ABELMOSCHUS ESCULENTUS (L.) MOENCH] TO NITROGEN DOSE AND SPACING ON GROWTH AND YIELD UNDER MULCH CONDITION, IN CHITWAN, NEPAL

Commercial farmers in Chitwan are unaware of optimum spacing and fertilizer dose which limits the performance and yield of okra [Abelmoschus esculentus (L.) Moench]. An experiment was conducted to assess the response of okra to different levels of nitrogen 60, 90 and 120kg.ha-1 and 30×30, 45×30 and 60×30cm2 spacing under plastic mulched condition in Bharatpur-16, Chitwan from March to May 2018, using Ramdomized Complete Block Design (RCBD) with 3 replications. A hybrid variety of okra (Venus plus) mostly employed by farmers in Chitwan was used. Data were collected from ten randomly selected plants from the central rows in each plot and growth parameters were analyzed of various yield related parameters taken. The tallest plants were for 120kg.ha-1N and for the 30×30cm2 spacing. Pods from the interaction of 90kg.ha-1N for spaced at 45×30cm2 had the widest, the heaviest and the longest. Pods per plant were greatest for plants receiving 120kg.ha-1N spaced at 60×30cm2. Yield was best and cost:benefit (BC) ratio was most favorable for 90kg.Nha-1 treatment and for plants spaced at 45×30cm2. Overall data indicates that the nitrogen dose of 90kg.ha-1N with a spacing of 45× 30cm2 showed the most effective result statistically and economically.

Performance of Intercrops under Different Spacings of Jatropha curcas Plantations in Tamil Nadu, India

Background: Non-edible oil as biodiesel helps to meet the energy demand and to reduce environmental degradation. Jatropha curcas is one of the potential oil yielding plant which can be grown under agroforestry systems without affecting food production. Hence the current study aimed to find out compatible intercrop under J. curcas and optimum spacing of J. curcas for intercropping. Methods: A study was carried out in three and a half-year old J. curcas plantation. Different spacings of J. curcas viz., 3m × 3m, 4m × 2m and 4m × 3m and different legumes viz., blackgram, greengram, cowpea, groundnut and oilseed crops viz., gingelly and sunflower were evaluated in split plot design. Result: Growth and yield of intercrops, available soil N, P and uptake of N, P, K by intercrops were significantly higher at wider spacing of J. curcas (4m × 3m). Among the intercrops, groundnut recorded higher uptake of N (67.3 kg ha-1), P (19.9 kg ha-1) and K (65.3 kg ha-1). Groundnut produced a significantly higher yield (885 kg ha-1) followed by cowpea (630 kg ha-1). The study found that planting of J. curcas at 4m × 3m spacing and intercropping with groundnut is a compatible and profitable J. curcas based agroforestry system.

Gibberellic Acid Application and Plant Spacing Effects on Growth and Yield of Lettuce (Lactuca sativa L.)

Aims: This study aimed to optimize the levels of gibberellic acid (GA3) and plant spacing on growth and yield of lettuce. Study Design: The experiment was laid out in Randomized Complete Block Design with three replications. Place and Duration of Study: Horticulture farm of Sher-e-Bangla Agricultural University, Dhaka-1207, from November 2013 to January 2014. Methodology: The experiment consisted of two factors. Factor A- two levels of gibberellic acid (GA3,) application, viz. G1= 25 ppm and G2= 50 ppm in relation to a control G0 and factor B- four plant spacing viz. S1=15cm x 15cm, S2=20 cm x 20 cm, S3=25 cm x 25 cm and S4=30 cm x 30 cm. GA3 was applied twice as a foliar application by hand sprayer at 20 and 30 days after sowing. First, second and final harvesting was done at 25, 35 and 45 days after sowing respectively. Results: The growth and yield characters of lettuce showed significant variation for different levels of GA3 and plant spacing. Among GA3 levels, 25 ppm GA3 produced the maximum number of leaves (15.6), leaf area (283.9 cm2), fresh weight (91.6 g plant-1), dry weight (11.8 g plant-1), fresh yield (1794 g plot-1) and gross yield (12 t ha-1) at final harvesting compared to control where GA3 was not used. Under plant spacing, highest plant height (17.5 cm), leaf area (281.1 cm2), fresh weight (99.1 g plant-1) and dry weight (12.1 g plant-1) was revealed from wider spacing 30 cm x 30 cm followed by optimum spacing 25cm x 25cm. Meanwhile, closure spacing 15 cm x 15 cm showed maximum fresh yield (1710 g plant-1) and gross yield (15.5 t ha-1) due to higher plant density at final harvesting. Besides, lower chlorophyll content (0.43%) and the highest number of leaves (16.2) was found from 25 cm x 25 cm at final harvesting. So, optimum spacing 25 cm x 25 cm would be more suitable considering different points of view. Moreover, the treatment combinations 25 ppm GA3 with 25 cm x 25 cm exhibited highest benefit-cost ratio (2.04) than other treatments. Conclusions: It is concluded that the combinations 25 ppm GA3 application with 25cm x 25cm spacing would be optimum for better growth and yield of lettuce

Erection of Formwork with Optimum Spacing of Joists and Stringers

The success of any project depends on suitable and economical formwork arrangements and it accounts about 25% in the overall cost. The project completion time depends on the erection and de-shuttering of formwork. Proper planning, management and safety is very important to finish the project within the cost budget and satisfactory quality. This study focuses on the conventional type of form work using timber joists and stringers loaded with different types of spacing in an actually erected model. The soil has been compacted, consolidated before the erection of model. After erections, the entire model has been subjected to sand bag loading with the specified loading capacity per sq. m. The deflections due to the added load on the formwork is characterized by standard deflectometer for different spacing of timber joists. Accordingly, the shores spacing have also been obtained with the designed load bearing capacity. With this study it has been found that the stability of formwork is analyzed based on vibrations and deflections. Hence the study infers that optimum spacing of joists designed should be decreased for minimum deflection. The vibrations and key factors for this erection have been identified and the results are presented.

Design, Development and Implementation of Automatic Transplanting based on Embedded System for use in Seedling Transplanters

Hand transplanting of vegetable seedlings is always been a time consuming and labourious activity which often leads to muscular fatigue. Use of hitech instrumentation increased to achieve precision and automation in agricultural operations. At present the transplanting is done manually which accounts for large amount of hand labour and time. To ensure precision and timeliness in operation, an automatic transplanting based on embedded system for use in seedling transplanters was developed. The developed system consists of feed roller, pro-tray belt, a pair of L-shaped rotating fingers, embedded system, DC and stepper motor. The pro-tray on the belt moves by DC motor whereas, the stepper motor was used to actuate the metering shaft to and from. The ground wheel used to rotate the rotating fingers which eject the seedling from the pro-tray into the delivery box. The performances of the developed system was tested rigorously at four different operating speeds (vf) (1.0, 1.5, 2.0 and 2.5 km/h) and three angles of pro-tray feed roller (00, 300, 450) for attaining optimum plant to plant spacing in soil bin. The result indicated that percent transplanting and plant to plant spacing was found optimum when speed of operation was 2.0 km/h and angle of pro-tray feed roller was 300. The average plant spacing, transplanting efficiency, furrow closer, angle of inclination and miss planting was 600 mm, 91.7%, 90.3%, 18.30 and 2.1%, respectively. The developed system ensures the precision by sigulating the placement of seedlings at optimum spacing. It also enabled the optimum transplanting rate, the ability to transplant at higher speeds and maintaining proper plant to plant spacing.

Thermally Optimum Spacing between Inner Plates in Natural Convection Flows in Cavities by Numerical Investigation

Buoyancy-driven airflow that included two isothermal inner plates established in a vented cavity is investigated numerically. The thermally optimum wall-to-wall spacing of the immersed channel, as well as its dependence with respect to the relevant governing parameters, are determined. Results are presented as a function of the aspect ratio b/H for a wide range of Rayleigh numbers RaH. A logarithmic correlation for the optimum (b/H)opt as a function of RaH is presented. In addition, since the outlined configuration might be subject to intense heating conditions, the influence of considering variable thermophysical properties is also included in the analysis. In fact, an appreciable influence of the variation of properties on (b/H)opt is also detected for a representative value of RaH = 109. Obtained results can be directly applied to the optimization of electronic equipment cooling, or even to thermal passive devices in buildings.