Mathematical model of a communication channel with an unmanned aerial vehicle

In this paper, a mathematical model of a communication channel with an unmanned aerial vehicle and taking into account the specifics of the locations of a ground communication point when determining the effects of refraction, diffraction and interference of electromagnetic waves is proposed. A meaningful statement of the problem based on the mathematical relationship between the energy parameters of the first transmission equation and the quality indicators (BER) of the second transmission equation has been formed. The main features of calculating the parameters of the first equation are to determine the rules for calculating the level of attenuation due to the influence of the earths surface. The calculation of attenuations for cases of removal of an unmanned aerial vehicle from a ground communication point within the areas of line of sight, partial shade and shadow has been clarified. The second transmission equation is based on the mathematical model of the Rice communication channel. With respect to the energy parameters and the selected communication quality indicator for the formed mathematical model, examples of graphical dependencies are given in the study of typical computational problems. With respect to the energy parameters and the selected communication quality indicator for the formed mathematical model, examples of graphical dependencies in the study of typical computational problems are given.

Heliconias with pendent inflorescences as cut flowers

The Heliconia species with pendent inflorescences and colorful bracts are a good option as a cut flower for floriculture market, but only a few species of this type of Heliconia eg. H. rostrata, H. rauliniana and H. chartacea are commercially produced in Brazil. This study was carried out to characterize 36 Heliconia accessions, with pendent inflorescences, to be used as cut flower, intending to increase knowledge and use of these exceptional plants among tropical flower enthusiasts and consumers. The evaluations were performed on plants of the Germplasm Collection of the Instituto Agronômico (IAC) growing in shade, partial shade or full sun conditions. Qualitative and quantitative characteristics, related to clump growth and flower stem aspects were analyzed. A point scoring system was used to determine the species most suitable for cut flower utilization. All evaluated genotypes reached enough points to be considered suitable for use as cut flowers, even those with large inflorescences and bracts arranged in different planes, facts that affect and limit handling, packaging and transportation. H. mariae, H. fernandezii, H. platystachys, H. rauliniana, H. rostrata, H. standley, H. necrobracteata and H. laxa were considered outstanding. This characterization and scoring system were important to facilitate the selection of heliconia genotypes for use as cut flowers.

A Hybrid MPPT Controller Based on the Genetic Algorithm and Ant Colony Optimization for Photovoltaic Systems under Partially Shaded Conditions

A maximum power point tracking (MPPT) controller was used to make the photovoltaic (PV) module operate at its maximum power point (MPP) under changing temperature and sunlight irradiance. Under partially shaded conditions, the characteristic power–voltage (P–V) curve of the PV modules will have more than one maximum power point, at least one local maximum power point and a global maximum power point. Conventional MPPT controllers may control the PV module array at the local maximum power point rather than the global maximum power point. MPPT control can be also implemented by using soft computing methods (SCM), which can handle the partial shade problem. However, to improve the robustness and speed of the MPPT controller, a hybrid MPPT controller has been proposed that combines two SCMs, the Genetic Algorithm (GA) and Ant Colony Optimization (ACO). Matlab was used in a simulation of a GA-ACO MPPT controller where four SunPower SPR-305NE-WHT-D PV modules with a maximum power of 305.226 W connected in series were used under conditions of partial shade to investigate the performance of the proposed MPPT controller. The results obtained were analyzed and compared with others obtained under perturb and observe (P&O) MPPT and conventional ACO MPPT controllers were observed.

Partial shading by solar panels delays bloom, increases floral abundance during the late-season for pollinators in a dryland, agrivoltaic ecosystem

Habitat for pollinators is declining worldwide, threatening the health of both wild and agricultural ecosystems. Photovoltaic solar energy installation is booming, frequently near agricultural lands, where the land underneath ground-mounted photovoltaic panels is traditionally unused. Some solar developers and agriculturalists in the United States are filling the solar understory with habitat for pollinating insects in efforts to maximize land-use efficiency in agricultural lands. However, the impact of the solar panel canopy on the understory pollinator-plant community is unknown. Here we investigated the effects of solar arrays on plant composition, bloom timing and foraging behavior of pollinators from June to September (after peak bloom) in full shade plots and partial shade plots under solar panels as well as in full sun plots (controls) outside of the solar panels. We found that floral abundance increased and bloom timing was delayed in the partial shade plots, which has the potential to benefit late-season foragers in water-limited ecosystems. Pollinator abundance, diversity, and richness were similar in full sun and partial shade plots, both greater than in full shade. Pollinator-flower visitation rates did not differ among treatments at this scale. This demonstrates that pollinators will use habitat under solar arrays, despite variations in community structure across shade gradients. We anticipate that these findings will inform local farmers and solar developers who manage solar understories, as well as agriculture and pollinator health advocates as they seek land for pollinator habitat restoration in target areas.

Digital record of specimens, including voucher material, from the study of a pollinator habitat restoration site under a commercial solar array in Jackson County, Oregon, 2019

Photovoltaic solar energy installation is booming, frequently near agricultural lands. Traditionally, the land underneath ground-mounted photovoltaic panels is unused, though some are repurposing it as habitat for pollinating insects. However, the impact of the solar panel canopy on the pollinator-plant community understory is unknown. In this study (Graham et al., 2020), we investigated the effects of solar arrays on plant composition, bloom timing and foraging behavior of pollinators in open fields (control), and in full shade and partial shade areas under solar panels in a predominant agricultural region of southern Oregon. Pollinating insect specimens were collected using hand nets, and identified to the lowest taxonomic group possible by M. Graham, A.R. Moldenke, and L.R. Best. A total of 85 voucher specimens were deposited into the Oregon State Arthropod Collection; accession record: OSAC_AC_2021_03_11_001-01.

Paspalum conjugatum (buffalo grass).

Paspalum conjugatum is a vigorous, creeping perennial grass with long stolons and dense culms that may grow up to 1 m tall. It has been extensively introduced as a forage and lawn grass and it can now be found naturalized across tropical and subtropical regions. P. conjugatum tolerates high levels of disturbance and pollution, grows vigorously under partial shade, spreads easily by seeds and stolons, and can withstand acidic and low-nutrient soils. Once established, this grass behaves as an aggressive weed in active pastures and agricultural lands, but also in disturbed and undisturbed natural forests and grasslands. It forms a dense ground cover that competes with and inhibits the establishment of other plant species, including other grasses and crops. In the Pacific region, it has been stated that some native forests have become extinct due to this grass pest.

Paspalum conjugatum (buffalo grass).

Paspalum conjugatum is a vigorous, creeping perennial grass with long stolons and dense culms that may grow up to 1 m tall. It has been extensively introduced as a forage and lawn grass and it can now be found naturalized across tropical and subtropical regions. P. conjugatum tolerates high levels of disturbance and pollution, grows vigorously under partial shade, spreads easily by seeds and stolons, and can withstand acidic and low-nutrient soils. Once established, this grass behaves as an aggressive weed in active pastures and agricultural lands, but also in disturbed and undisturbed natural forests and grasslands. It forms a dense ground cover that competes with and inhibits the establishment of other plant species, including other grasses and crops. In the Pacific region, it has been stated that some native forests have become extinct due to this grass pest.