Benomyl Effects on Plant Productivity through Arbuscular Mycorrhiza Restriction in a Greek Upland Grassland

Interactions between plants and microbes are important for plant community structure. Many plants establish symbioses with arbuscular mycorrhizal (AM) fungi, which play a central role in soil fertility, plant nutrition and the maintenance of stability and biodiversity within plant communities by improving uptake of nutrients and water. AM fungi can improve growth/performance in a variety of plant species by influencing intra- and interspecific competition of neighbouring plants and thus regulate coexistence and diversity in mixed communities. The aim was to study AMF effects on plant productivity and diversity in Greek upland grasslands

Loss comparison of 2 and 3-level inverter topologies

This paper investigates semiconductor and DC-link capacitor losses in two two-level and two three-level voltage source inverters. The components of the four inverters are selected to have appropriate voltage and current ratings. Analytical expressions for semiconductor losses are reviewed and expressions for DC link capacitor losses are derived for all topologies. Three-level inverters are found to have lower semiconductor losses, but higher DC-link capacitor losses. Overall, the three-level Neutral-Point-Clamped inverter proved to be the most efficient topology

Analysis of DC-Link capacitor losses in three-level neutral point clamped and cascaded H-Bridge voltage source inverters

Loss estimation is a critical aspect of inverter design.The present work investigates the losses occurring in the DC-link capacitors of the three-phase three-level neutral point clamped and cascaded H-Bridge inverter topologies, by performing a harmonic analysis of the capacitor currents.Results are verified by simulations. Their analysis reveals the advantage of the NPC inverter

Hybrid modulation strategies for eliminating low-frequency neutral-point voltage oscillations in the neutral-point-clamped converter

Nearest vector (NV) modulation strategies for the neutral-point-clamped converter are known to generate low-frequency neutral point (NP) voltage oscillations. Non-NV strategies can eliminate these oscillations, but at the expense of higher switching losses and output voltage harmonic distortion. This letter proposes a simple way of creating hybrid strategies, as combinations of NV and non-NV strategies, which are also able to eliminate NP voltage oscillations. The approach minimizes the participation of non-NV strategies and hence their drawbacks, while it can be applied to any type of load (nonlinear and/or unbalanced). Simulations in MATLAB-Simulink are used to illustrate its operation.<br/

Current balancing of scalar-controlled induction motors with long imbalanced cables for artificial lift systems

Induction motor current imbalance increases losses, torque ripple and vibrations. Current imbalance is known to appear in artificial lift systems, where motors are driven over long imbalanced cables. Power hardware modifications, namely transposition of cable phases in the wellbore, adjustment of the step-up transformer taps, and addition of balancing inductors have so far been proposed to suppress the imbalance. However, these solutions compromise the system's reliability or involve costly additional equipment, which must be customized according to the cable characteristics. This paper proposes a control method for current balancing of induction motors driven by scalar-controlled variable speed drives. In the proposed method, Second-Order Generalized Integrators (SOGIs) are used to extract the negative-sequence component of the motor currents, which is then suppressed by a Synchronous Reference Frame (SRF) current controller. The frequency and angle information required by the SOGIs and the SRF controller are obtained directly from the scalar algorithm, without needing a position sensor or observer, thus offering a novel, simple, robust and computationally effective implementation, which is also independent of the cable characteristics. The paper presents MATLAB/Simulink simulation results to illustrate the method's operating principles and performance in a variety of transient conditions. Experimental results obtained using full-scale equipment are also provided to demonstrate its effectiveness

Effects of Arbuscular Mycorrhiza Fungi on Growth Characteristics of <i>Dactylis glomerata</i> L. under Drought Stress Conditions

Limited information is available regarding the selection of effective mycorrhizae and the exploitation of their beneficial effects on the enhancement of the forage production of Dactylis glomerata under the predicted warmer and drier conditions in the Mediterranean region. The objective of this study was to test the effects of Glomus intraradices, Glomus mosseae and their mix inoculation on growth characteristics and dry matter production of Dactylis glomerata in relation to full and limited irrigation. The experiment was conducted in Orestiada, Northeastern Greece. Limited irrigation significantly decreased yield and yield components of Dactylis glomerataover the full irrigation. Drought stressed plants had significantly higher root dry weight as a response for better survival under water deficit conditions. The Arbuscular mycorrhizal fungi (AMF) inoculated plants had significant higher shoot dry weight, tiller height and number of leaves in comparison to the non-inoculated plants. On the contrary, under drought stress conditions all AMF plants had lower root dry weights than control plants. Among the studied mycorrhizae species, Glomus intraradices performed better than Glomus mosseae and their mixture as it increased S/R ratio, tiller height and number of leaves

Effects of Arbuscular Mycorrhiza Fungi on Growth Characteristics of <i>Dactylis glomerata</i> L. under Drought Stress Conditions

Limited information is available regarding the selection of effective mycorrhizae and the exploitation of their beneficial effects on the enhancement of the forage production of Dactylis glomerata under the predicted warmer and drier conditions in the Mediterranean region. The objective of this study was to test the effects of Glomus intraradices, Glomus mosseae and their mix inoculation on growth characteristics and dry matter production of Dactylis glomerata in relation to full and limited irrigation. The experiment was conducted in Orestiada, Northeastern Greece. Limited irrigation significantly decreased yield and yield components of Dactylis glomerataover the full irrigation. Drought stressed plants had significantly higher root dry weight as a response for better survival under water deficit conditions. The Arbuscular mycorrhizal fungi (AMF) inoculated plants had significant higher shoot dry weight, tiller height and number of leaves in comparison to the non-inoculated plants. On the contrary, under drought stress conditions all AMF plants had lower root dry weights than control plants. Among the studied mycorrhizae species, Glomus intraradices performed better than Glomus mosseae and their mixture as it increased S/R ratio, tiller height and number of leaves

Enamel sign plates on fence advertising velvet soap and trade mark pears, Victoria, approximately 1925.

Title devised by cataloguer based on inscription.; Part of the collection: Victorian Railways outdoor advertising, between 1910 and 1950.; Inscriptions: "Enamel plates"--In ink below image.; Condition: Buckled and soiled.; Also available online at: http://nla.gov.au/nla.pic-vn6251947