Influence of shape of cutting tool on pressure conditions in workspace of mulcher with vertical axis of rotation

ArticleNowadays there is laid great insistence on work efficiency improvement. This effort also affects the construction of mowers such as mulchers. Mulching with a vertical axis of rotation is very energy demanding work operation mainly, due to high energy losses. These energy losses, but also the quality of work, are influenced by the airflow and associated conditions of pressure inside the workspace of mulcher. Airflow in the workspace ensures repetitious contact of the truncated forage crops with the cutting edge tool and thus ensures crushing of aboveground parts of plants. The paper deals with the influence of the cutting tool shape on the mulcher’s inside workspace pressure conditions with the vertical axis of rotation. The influence of the trailing edge angle and rake angle on the pressure profile in the mulcher’s workspace with dependence on the rotor speed was examined. Measurements were performed on a laboratory single rotor mulcher model. It was found that in the mulcher’s workspace the vacuum is formed by virtue of the rotary movement of the cutting tools wherein the vacuum increases with rotor speed. The maximum measured vacuum was about 2.4 kPa and from the centre of the rotor towards its circumference almost linearly decreases. Furthermore, it was found that with decreasing trailing edge angle and with increasing rake angle the maximum vacuum decreases. When reducing the angle of the trailing edge from 45° to 25° led to reduction of vacuum of about 0.3 kPa (12.6%)

Air flow conditions in workspace of mulcher

ArticleCurrently, there has been a great effort on increasing the efficiency of agricultural machinery. The energy demands of mulching with the vertical axis of rotation depends on the amount of pr ocessed material per unit of time, its properties and efficiency of material processing. Another important factor that is affecting the overall energy demands is the energy losses, which can be even higher than energy, required for the processing of materi al. The efficiency of the material processing and the energy losses are influenced to a large extent by the air flow inside the mulcher workspace, which is created by the movement of working tools. The air flow ensures the repeated contact of the processed material with the working tools, affects the energy losses and the quality of work. The contribution deals with the air flow conditions inside the workspace of mulcher with the vertical axis of rotation. The velocity of the air flow was measured my means of LDA (Laser Doppler Anemometry) method in three planes above the surface (180, 100 and 20 mm ) and in two directions (peripheral and radial). The laboratory model of one mulcher rotor from mulcher MZ 6000 made by BEDNAR Ltd. company was used for the measu rement. From the results it is evident that the maximum values of peripheral velocity of the air flow reach approx. 50% of the velocity of the tools. In the radial plane an air vortex is created between 20 and 100 mm planes above the surface around the tip of the blade

phot1 inhibition of ABCB19 primes lateral auxin fluxes in the shoot apex required for phototropism

It is well accepted that lateral redistribution of the phytohormone auxin underlies the bending of plant organs towards light. In monocots, photoreception occurs at the shoot tip above the region of differential growth. Despite more than a century of research, it is still unresolved how light regulates auxin distribution and where this occurs in dicots. Here, we establish a system in Arabidopsis thaliana to study hypocotyl phototropism in the absence of developmental events associated with seedling photomorphogenesis. We show that auxin redistribution to the epidermal sites of action occurs at and above the hypocotyl apex, not at the elongation zone. Within this region, we identify the auxin efflux transporter ATP-BINDING CASSETTE B19 (ABCB19) as a substrate target for the photoreceptor kinase PHOTOTROPIN 1 (phot1). Heterologous expression and physiological analyses indicate that phosphorylation of ABCB19 by phot1 inhibits its efflux activity, thereby increasing auxin levels in and above the hypocotyl apex to halt vertical growth and prime lateral fluxes that are subsequently channeled to the elongation zone by PIN-FORMED 3 (PIN3). Together, these results provide new insights into the roles of ABCB19 and PIN3 in establishing phototropic curvatures and demonstrate that the proximity of light perception and differential phototropic growth is conserved in angiosperm

Spine neck plasticity regulates compartmentalization of synapses

Dendritic spines have been proposed to transform synaptic signals through chemical and electrical compartmentalization. However, the quantitative contribution of spine morphology to synapse compartmentalization and its dynamic regulation are still poorly understood. We used time-lapse super-resolution stimulated emission depletion (STED) imaging in combination with fluorescence recovery after photobleaching (FRAP) measurements, two-photon glutamate uncaging, electrophysiology and simulations to investigate the dynamic link between nanoscale anatomy and compartmentalization in live spines of CA1 neurons in mouse brain slices. We report a diversity of spine morphologies that argues against common categorization schemes and establish a close link between compartmentalization and spine morphology, wherein spine neck width is the most critical morphological parameter. We demonstrate that spine necks are plastic structures that become wider and shorter after long-term potentiation. These morphological changes are predicted to lead to a substantial drop in spine head excitatory postsynaptic potential (EPSP) while preserving overall biochemical compartmentalization

Over-expression of the IGI1 leading to altered shoot-branching development related to MAX pathway in Arabidopsis

Shoot branching and growth are controlled by phytohormones such as auxin and other components in Arabidopsis. We identified a mutant (igi1) showing decreased height and bunchy branching patterns. The phenotypes reverted to the wild type in response to RNA interference with the IGI1 gene. Histochemical analysis by GUS assay revealed tissue-specific gene expression in the anther and showed that the expression levels of the IGI1 gene in apical parts, including flowers, were higher than in other parts of the plants. The auxin biosynthesis component gene, CYP79B2, was up-regulated in igi1 mutants and the IGI1 gene was down-regulated by IAA treatment. These results indicated that there is an interplay regulation between IGI1 and phytohormone auxin. Moreover, the expression of the auxin-related shoot branching regulation genes, MAX3 and MAX4, was down-regulated in igi1 mutants. Taken together, these results indicate that the overexpression of the IGI1 influenced MAX pathway in the shoot branching regulation

A comprehensive framework for fluorescence cross-correlation spectroscopy

Dual-colour fluorescence cross-correlation spectroscopy is a powerful method of studying binding between labelled biomolecules in vitro as well as in vivo. However, numerous artefacts and experimental complexities complicate quantitative measurements. Here, we show that a combination of dual-colour fluorescence correlation spectroscopy (FCS) with dual-focus FCS avoids artefacts due to chromatic aberrations or saturation and circumvents the calibration of the detection volumes. In addition, we present a comprehensive mathematical framework that allows us to accurately analyse correlation curves even in the presence of spectral cross-talk, incomplete or stochastic labelling, multiple binding sites, a fluorescent background and depletion due to photobleaching. We demonstrate the merits of this approach using dual-colour dual-focus scanning FCS, which allows binding measurements on membranes not affected by membrane movements