Abstract: The harmonic distortion of voltage is important in relation to power quality due to the interaction between the large diffusion of non-linear and time-varying single-phase and three-phase loads with power supply systems. However, harmonic distortion levels can be reduced by improving the design of polluting loads or by applying arrangements and adding filters. The application of passive filters is an effective solution that can be used to achieve harmonic mitigation mainly because filters offer high efficiency, simplicity, and are economical. Additionally, possible different frequency response characteristics can work to achieve certain required harmonic filtering targets. With these ideas in mind, the objective of this paper is to determine what size single tuned passive filters work in distribution networks best, in order to economically limit violations caused at a given point of common coupling (PCC). This article suggests that a single tuned passive filter could be employed in typical industrial power systems. Furthermore, constrained optimization can be used to find the optimal sizing of the passive filter in order to reduce both harmonic voltage and harmonic currents in the power system to an acceptable level, and, thus, improve the load power factor. The optimization technique works to minimize voltage total harmonic distortions (VTHD) and current total harmonic distortions (ITHD), where maintaining a given power factor at a specified range is desired. According to the IEEE Standard 519, both indices are viewed as constraints for the optimal passive filter design problem. The performance of this technique will be discussed using numerical examples taken from previous publications.
Abstract: The use of engineered nanomaterials has increased as
a result of their positive impact on many sectors of the economy,
including agriculture. Silver nanoparticles (AgNPs) are now used to
enhance seed germination, plant growth, and photosynthetic quantum
efficiency and as antimicrobial agents to control plant diseases. In
this study, we examined the effect of AgNP dosage on the seed
germination of three plant species: corn (Zea mays L.), watermelon
(Citrullus lanatus [Thunb.] Matsum. & Nakai) and zucchini
(Cucurbita pepo L.). This experiment was designed to study the
effect of AgNPs on germination percentage, germination rate, mean
germination time, root length and fresh and dry weight of seedlings
for the three species. Seven concentrations (0.05, 0.1, 0.5, 1, 1.5, 2
and 2.5 mg/ml) of AgNPs were examined at the seed germination
stage. The three species had different dose responses to AgNPs in
terms of germination parameters and the measured growth
characteristics. The germination rates of the three plants were
enhanced in response to AgNPs. Significant enhancement of the
germination percentage values was observed after treatment of the
watermelon and zucchini plants with AgNPs in comparison with
untreated seeds. AgNPs showed a toxic effect on corn root
elongation, whereas watermelon and zucchini seedling growth were
positively affected by certain concentrations of AgNPs. This study
showed that exposure to AgNPs caused both positive and negative
effects on plant growth and germination.
Abstract: The use of engineered nanomaterials has increased as
a result of their positive impact on many sectors of the economy,
including agriculture. Silver nanoparticles (AgNPs) are now used to
enhance seed germination, plant growth, and photosynthetic quantum
efficiency and as antimicrobial agents to control plant diseases. In
this study, we examined the effect of AgNP dosage on the seed
germination of three plant species: corn (Zea mays L.), watermelon
(Citrullus lanatus [Thunb.] Matsum. & Nakai) and zucchini
(Cucurbita pepo L.). This experiment was designed to study the
effect of AgNPs on germination percentage, germination rate, mean
germination time, root length and fresh and dry weight of seedlings
for the three species. Seven concentrations (0.05, 0.1, 0.5, 1, 1.5, 2
and 2.5 mg/ml) of AgNPs were examined at the seed germination
stage. The three species had different dose responses to AgNPs in
terms of germination parameters and the measured growth
characteristics. The germination rates of the three plants were
enhanced in response to AgNPs. Significant enhancement of the
germination percentage values was observed after treatment of the
watermelon and zucchini plants with AgNPs in comparison with
untreated seeds. AgNPs showed a toxic effect on corn root
elongation, whereas watermelon and zucchini seedling growth were
positively affected by certain concentrations of AgNPs. This study
showed that exposure to AgNPs caused both positive and negative
effects on plant growth and germination.