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  • Author: M.R. Islam x
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The purpose of this paper is to calculate the reduction of specific absorption rate (SAR) with a new design of square metamaterials (SMMs). The finite-difference time-domain (FDTD) method with lossy-Drude model is adopted in this analysis. The method of SAR reduction is discussed and the effects of location, distance, and size of metamaterials are analyzed. SMMs have achieved a 53.06% reduction of the initial SAR value for the case of 10 gm SAR. These results put forward a guideline to select various types of metamaterials with the maximum SAR reducing effect for a cellular phone.

Abstract

The experiment was conducted during Rabi season of 2015-2016 and 2016-2017 at the Regional Agricultural Research station, BARI, Ishurdi, Pabna, Bangladesh, to determine the water requirements of wheat on raised bed and the effect of different deficit irrigation on yield, water use efficiency and applied water productivity under raised bed wheat. This study consisted of following irrigation treatments: T1 = Irrigations up to 100% field capacity (FC) at crown root initiation (CRI), botting and grain filling stages (flat bed), T2 = Irrigations up to 100% FC at CRI, botting and grain filling stages on raised bed, T3 = Irrigations up to 80% FC at CRI, botting and grain filling stages on raised bed and T4 = Irrigations up to 60% FC at CRI, botting and grain filling stages on raised bed and laid out in a randomize complete block design with three replications. The result showed that significant effect of irrigation treatments were observed on plant height, spike per m2 and grain yield. Highest grain yield (4.66 t/ha) was obtained from treatment, irrigations up to 100% FC at CRI, botting and grain filling stages on raised bed, followed by irrigation up to 100% FC at same stages on flat bed. At raised bed wheat cultivation saving 14.30% water with increasing 15.66% grain yield than flat bed. Besides, comparing deficit irrigation (20% and 40% of full irrigation) and full irrigation condition on raised bed seeding system water use could be reduced about 4.18% to 5.57%, while scarifying 18.20% to 32.33% grain yield, where reduced 14.17% to 27.54% water use efficiency. Maximum applied water productivity 1.81 kg m−3 was observed in raised bed full irrigation condition. The rate of daily evaporation started to increase as the temperature started to rise and humidity started to decrease during the crop growing period. The results will be helpful for taking policy decision regarding efficient irrigation and water management under prevailing water scarce situation.

Abstract

Effectiveness of sesame intercropping in mungbean for the management of flower thrips and pod borer of mungbean was studied at Pulses Research Centre, Ishurdi, Pabna, Bangladesh, during two consecutive season of kharif-I 2017 and 2018. Sesame intercropping in mungbean reduced flower thrips infestation and pod borer infestation significantly in both the years. Among the intercropped treatments, mungbean: sesame at 2:2 row ratio arrangements was found the best intercropping arrangements in reducing flower thrips and pod borer infestation. Sesame intercropping showed statistically similar performance in reducing pod borer infestation, as like as insecticide spraying (Imitaf 20 SL @ 0.5 ml/l). Mungbean equivalent yield varied depending on the prevailing weather condition of the cropping season and market prices of both mungbean and sesame, but the total production was always higher in intercropped treatments than sole cropping of mungbean. Hence, sesame intercropping in mungbean might be eco-friendly management approach against flower thrips and pod borers of mungbean providing higher production and benefit.

Abstract

The experiment was conducted at the Regional Agricultural Research Station, BARI, Ishwardi, Pabna, Bangladesh, during 2013-2014 and 2014-2015 to introduce maize as relay crop with T. Aman rice under different agronomic practices for determine the production potentials. The experiment was design split plot with three replications. The agronomic management practices included four plant spacing viz. S1=75 cm×20 cm (66666 plants/ha), S2=60 cm×20 cm (83333 plants/ha), S3=50 cm×20 cm (100000 plants/ha) and S4=40 cm×20 cm (125000 plants/ha) and four soil management practices viz. M1=soil mulching at 25 DAE, M2=earthing up at 25 DAE, M3=straw mulching at 25 DAE and M4= without earthing up and mulching (control). Seeds were relayed by dibbling manually in 10 days before the harvest of T. Aman rice. Results showed that an increasing plant spacing increased leaf area Index (LAI), total dry matter (TDM), crop growth rate (CGR) and light energy interception (LEI). Grain yield was higher in S3 spacing (8.44 t/ha) than others (S4 8.11 t/ha, S2 7.34 t/ha and S1 6.89 t/ha). Among the soil management practices, M2 increased LAI, TDM, CGR, LEI as well as grain yield. Moreover, M2 and M1 gave similar grain yield (8.22 t/ha and 8.02 t/ha), that were significantly greater than other two soil management practices (M3 7.55 t/ha and M4 6.98 t/ha). From the economic point of view, combination of S3M1 gave better performance with gross margin of Tk. 95000/ha and BCR of 2.17. On the basis of results, S3M1 combination was suitable for growing maize under relay sowing with T. Aman rice.

Abstract

A laboratory experiment regarding germination and seedling growth test was conducted with three black gram genotypes tested under three salinity levels (0, 75 and 150 mM), for 10 days, in sand culture within small plastic pot, to investigate the germination and seedling growth characteristics. Different germination traits of all black gram genotypes, like germination percentage (GP), germination rate (GR), coefficient of velocity of germination (CVG) greatly reduced, as well as mean germination time (MGT) increased with increasing salt stress. At high salt stress, BARI Mash-3 provided the highest GP reduction (28.58%), while the lowest was recorded (15.79% to control) in BARI Mash-1. Salinity have the negative impact on shoot and root lengths, fresh and dry weights. The highest (50.32% to control) and lowest reduction (36.39%) of shoot length were recorded in BARI Mash-2 and BARI Mash-1, respectively, under 150 mM NaCl saline conditions. There were significant reduction of root lengths, root fresh and dry weight, shoot length, shoot fresh and dry weight in all genotypes under saline condition. The genotypes were arranged as BARI Mash-1 > BARI Mash-3 > BARI Mash-2, with respect to salinity tolerance.