Journal articles: 'Oscillating plant'

1

Rose, Mary Ann, and Mark A. Rose. "Oscillatory Transpiration May Complicate Stomatal Conductance and Gas-exchange Measurements." HortScience 29, no. 6 (June 1994): 693–94. http://dx.doi.org/10.21273/hortsci.29.6.693.

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A closed-loop photosynthesis system and a heat-balance sap-flow gauge independently confirmed oscillatory transpiration in a greenhouse-grown Rosa hybrids L. Repetitive sampling revealed 60-minute synchronized oscillations in CO2-exchange rate, stomatal conductance, and whole-plant sap-flow rate. To avoid confusing cyclical plant responses with random noise in measurement, we suggest that gas-exchange protocols begin with frequent, repetitive measurements to determine whether transpiration is stable or oscillating. Single measurements of individual plants would be justified only when transpiration is steady state.

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Kourie, J. I. "Oscillation of Membrane Currents During the Action Potential in Chara corallina: Modification and Significance for Repolarisation of the Membrane Potential and Salt Sensitivity." Functional Plant Biology 23, no. 3 (1996): 361. http://dx.doi.org/10.1071/pp9960361.

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Depolarising voltage-clamp steps in C. corallina induced membrane currents which differ from those of C. inflata in two aspects: (1) The absence of a 'hump', i.e. a transient outward current,Io(max) which is present in C. inflata, and (2) the presence in C, corallina of a voltage-dependent current oscillation, i.e. a succession of decaying peaks. The peaks of the oscillating transient inward current, Ii(max), were voltage dependent and sensitive to block with 9-anthracenecarboxylic acid (9-AC). The oscillating current is carried by C1- and its time course is determined by the activation and inactivation kinetics of C1- channels. Extracellular NaCl delayed current activation, induced a voltage-dependent increase in Ii(max) and a decrease in the steady-state outward K+ current, Is. NaCl increased the occurrence of oscillation and enhanced the amplitude of the oscillating current. Extracellular sorbitol induced an overall reduction in Ii(max) and had virtually no effect on Is. I suggest that the enhancement of the oscillating transient inward CI- current, Ii(max), by NaCl is due to ionic effects of NaCl rather than to its osmotic effects.

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Chen, Yun, Jian Zhao, Guangrui Hu, and Jun Chen. "Design and Testing of a Pneumatic Oscillating Chinese Wolfberry Harvester." Horticulturae 7, no. 8 (July 29, 2021): 214. http://dx.doi.org/10.3390/horticulturae7080214.

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A pneumatic oscillating Chinese wolfberry harvester was designed to improve the efficiency of manual harvesting and minimize fruit damage by mechanical harvesting. The shedding model of Chinese wolfberry under pneumatic forces was established based on kinetic analysis, and the flow field characteristics were investigated using computational fluid dynamics (CFD). The position and shape of the fan outlet were determined by comparing the effects of a linear reduction outlet and a Laval reduction outlet on the outlet airflow rate. The size of the oscillating mechanism was optimized with nonlinear constraints to achieve uniform oscillation of the airflow. A three-factor, three-level orthogonal test was conducted on the NingQi 7 wolfberry variety. The flow rate at the outlet, the oscillation frequency, and the outlet distance were the test factors, and the net harvesting rate of ripe fruits, the harvesting rate of green fruits, and the damage rate of ripe fruits were the test indices. The results showed that the net harvesting rate of ripe fruits was 85.21% at an outlet distance of 10 cm, an outlet flow rate of 70 m·s−1, and an oscillation frequency of 2 Hz. This study provides references for the design of pneumatic harvesters for Chinese wolfberry.

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Jolibois, Nicklas, Krasimir Aleksandrov, Manuela Hauser, Dieter Stapf, Helmut Seifert, Jörg Matthes, Patrick Waibel, Markus Vogelbacher, Hubert B. Keller, and Hans-Joachim Gehrmann. "Analysis of Oscillating Combustion for NOx−Reduction in Pulverized Fuel Boilers." Inventions 6, no. 1 (January 19, 2021): 9. http://dx.doi.org/10.3390/inventions6010009.

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Thermal power plants in different fields are regularly adapted to the state-of-the-art emissions standards, applying “The Best Available Techniques Reference”. Since 2016 in the power plant area new, more stringent limits for power plant units with a thermal output of more than 300 MW operated with black coal are valid. Usually, in order to reach the new limits e.g., for NOX emissions, downstream reduction processes (Selective Non-Catalytic Reduction, SNCR or Selective Catalytic Reduction) are applied, which use of operating resources (essentially ammonia water) thereby increase. By the means of an experimentally validated process, by which pulverized fuel is fed by oscillation through a swirl burner into a pilot combustion chamber with a thermal output of 2.5 MW, nitrogen oxides can be reduced without further activities, for instance from 450 mg/mN3 in non-oscillation operation mode (0 Hz) to 280 mg/mN3 in oscillation operation mode (3.5 Hz), normalized to an O2–content of 6% each. These findings were patented in EP3084300. Particularly promising are the experiments which utilize oscillation of a large portion of the burn out air instead of the fuel in order to minimize the fatigue of the pulverized fuel oscillator, amongst others. Thereby, the nitrogen conversion rate, which describes the ratio of NOX to fuel nitrogen, including thermal NOX can be reduced from 26% for non-oscillation operation mode down to 16%. The present findings show that fuel oscillation alone is not sufficient to achieve nitrogen oxides concentrations below the legislative values. Therefore, a combination of different primary (and secondary) measures is required. This paper presents the experimental results for oscillating coal-dust firing. Furthermore, an expert model based on a multivariate regression is developed to evaluate the experimental results.

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Georgiou, Demos P., Kypros F. Milidonis, and Eleutherios N. Georgiou. "Sensitivity Analysis for the Encaged Turbine Concept in Oscillating Water Column Plants." ISRN Renewable Energy 2012 (December 20, 2012): 1–8. http://dx.doi.org/10.5402/2012/987904.

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Oscillating water column plants are one of the most popular wave energy device types. Prototype OWC units have been operating in various parts of the world since the mid-1980s and such developers have more field experience of this technology than any other relevant plant. The most common turbine used is the self-rectifying Well's turbine which has a rather low peak efficiency if compared to other designs but was preferred in terms of its simplicity and cycle performance. The present study exploits the merits of a new concept for the power extraction process, that of an encaged turbine for OWC plants, which allows conventional high-efficiency turbines to be employed in such plants. This is achieved by guiding the pressurized air into a sequence of three chambers, creating a unidirectional closed air circuit through the turbine. A theoretical model is deployed simulating the operation of the plant and a sensitivity analysis is carried out for the design and working parameters. Results indicate that the power extraction efficiency may exceed the 50% level in a real plant.

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Bulgakov, Volodymyr, Aivars Aboltins, Hristo Beloev, Volodymyr Nadykto, Volodymyr Kyurchev, Valerii Adamchuk, and Viktor Kaminskiy. "Experimental Investigation of Plow-Chopping Unit." Agriculture 11, no. 1 (January 4, 2021): 30. http://dx.doi.org/10.3390/agriculture11010030.

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The article presents research results of a machine-tractor unit that performs two technological operations simultaneously: (i) chopping plant residues (sunflower stubble); (ii) covering the chopped stubble with the soil. The first operation is carried out with a front-mounted plant residues chopper, and the second one is carried out with a rear-mounted plough. The chopper’s working devices are rotated by the tractor’s front power take-off (PTO), which has two operating modes: 540 and 1000 rpm. It was determined that to reduce the dynamic load in the drive of the chopper’s plant residues working devices, to chop these residues qualitatively, and then to cover them with the soil, the tractor’s front PTO should be adjusted to a speed of 1000 rpm. With this mode of the chopper’s working device’s rotation, the difference in its vertical vibrations’ dispersion and the tractor front axle’s oscillations is insignificant. The variance of the plowing depth vibrations (1.44 cm2), changing aperiodically in the frequency range of 0–2.5 Hz, is not accidentally less than the variance of irregularities vibrations of the longitudinal field profile (2.75 cm2). The plough draft resistant oscillations of the plow-chopping unit had the least impaction at the plowing depth oscillations. The proof of this is the small value of the cross correlation function; for such oscillating processes as ‘plough draft resistance—plowing depth’, it was equal to 0.22, which is 3.4 times less than for oscillating processes ‘surface’s longitudinal profile—plowing depth’. The number of chopped particles less than 15 cm in length increased by 1.5 times, and the number of particles longer than 30 cm decreased by 3 times. With the complete incorporation of plant residues into the soil, their non-chopped part did not exceed 1%.

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Kochergin, Victor I., Sergey P. Glushkov, and Aleksandr V. Kurmygin. "RESEARCH OF NON-UNIFORM ROTATION OF SHIP POWER PLANT ELEMENTS DRIVE." Russian Journal of Water Transport, no. 65 (November 23, 2020): 71–79. http://dx.doi.org/10.37890/jwt.vi65.129.

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This article contains the results of studies of the rotation unevenness parameters of the ship power plants elements drive. Theoretical prerequisites of such analysis are described and an example of calculation of parameters of torsional-oscillating system of high-pressure fuel pump drive and speed controller is given in the article. Calculations have shown that at the nominal crankshaft speed of the internal combustion engine, the possibility of resonant oscillations of the camshaft of the fuel pump is not excluded. Design features, faults, violation of adjustments or operating rules can contribute to the operation of elements of power plants at resonant frequencies and cause operational failures. Analysis of rotation unevenness of elements drive and additional equipment of ship's power plants is an appropriate technical measure that allows to increase the reliability of ship's power plants.

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Horntvedt, Bjarne R., Morten Rambekk, and Rune Bakke. "Oscillating conditions for influencing the composition of mixed biological cultures." Water Science and Technology 37, no. 4-5 (February 1, 1998): 259–62. http://dx.doi.org/10.2166/wst.1998.0640.

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This paper presents a strategy in which mixed biological cultures are exposed to oscillating concentration levels, to improve the potential for coexistence of desired bacterial species. A mechanistic mathematical model is constructed to investigate and illustrate this strategy. This paper is focused on competition between nitrifying, denitrifying and aerobic heterotrophic bacteria in a CSTR with sludge recycle. For nitrifying and aerobic heterotrophic cultures, the effect of sinusoidal oscillations in DO levels with an amplitude of 1.0 mg/l is a 16% specific growth rate reduction compared to that at a constant DO level. The denitrifiers growth rate is increased by an average of 59%, compared to the constant DO level situation. A similar strategy has been tested in a pilot plant. It is concluded that the influence on specific growth rates is a function of the amplitude of the oscillations. The effects are greatest when concentrations fluctuate around the half saturation concentration of the rate limiting component(s).

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Katharina E., Urban. "Oscillating vegetation dynamics in a wet heathland." Journal of Vegetation Science 16, no. 1 (2005): 111. http://dx.doi.org/10.1658/1100-9233(2005)016[0111:ovdiaw]2.0.co;2.

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Urban, Katharina E. "Oscillating vegetation dynamics in a wet heathland." Journal of Vegetation Science 16, no. 1 (February 2005): 111–20. http://dx.doi.org/10.1111/j.1654-1103.2005.tb02344.x.

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11

Heath, T. V. "A review of oscillating water columns." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 370, no. 1959 (January 28, 2012): 235–45. http://dx.doi.org/10.1098/rsta.2011.0164.

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This paper considers the history of oscillating water column (OWC) systems from whistling buoys to grid-connected power generation systems. The power conversion from the wave resource through to electricity via pneumatic and shaft power is discussed in general terms and with specific reference to Voith Hydro Wavegen's land installed marine energy transformer (LIMPET) plant on the Scottish island of Islay and OWC breakwater systems. A report on the progress of other OWC systems and power take-off units under commercial development is given, and the particular challenges faced by OWC developers reviewed.

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12

Gradmann, Dietrich. "Models for oscillations in plants." Functional Plant Biology 28, no. 7 (2001): 577. http://dx.doi.org/10.1071/pp01017.

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Ionic relations of plant cells comprise enzymes such as channels, pumps and co-transporters that catalyse the transition of ions through lipid membranes and, therefore, affect the membrane voltage. Since the activity of most of these enzymes is voltage dependent, these enzymes interact with each other via voltage changes. The temporal patterns of these interactions include oscillations. Models are presented here that simulate such oscillations based on physical properties of the ion transporters. Three oscillating scenarios are focussed on. Model A is adequate for short-term episodes. In model B, the external concentration of the ions is constant. This model, which applies e.g. to algae and single cells under experimental conditions, displays electric oscillations, just as model A, but also osmotic oscillations in which the internal ion concentrations play an essential role. Finally, model C applies to parenchyma cells in planta, where ion fluxes across the plasmalemma cause major concentration changes in the small apoplastic volume. In this model, internal and external buffering of ions is accounted for. For model C, it is assumed that the total quantities of substrates are constant, and portions of them are redistributed between different compartments. Oscillations of the model C are relatively rare. In most cases, model C approaches a steady state where K+ is in thermodynamic equilibrium.

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Mangano, Silvina, Javier Martínez Pacheco, Cristina Marino-Buslje, and José M. Estevez. "How Does pH Fit in with Oscillating Polar Growth?" Trends in Plant Science 23, no. 6 (June 2018): 479–89. http://dx.doi.org/10.1016/j.tplants.2018.02.008.

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M’zoughi, Fares, Soufiene Bouallègue, Aitor J. Garrido, Izaskun Garrido, and Mounir Ayadi. "Water cycle algorithm–based airflow control for oscillating water column–based wave energy converters." Proceedings of the Institution of Mechanical Engineers, Part I: Journal of Systems and Control Engineering 234, no. 1 (February 15, 2018): 118–33. http://dx.doi.org/10.1177/0959651818755293.

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The stalling behavior is a feature of the Wells turbine that limits the generated output power of power plants using this turbine. The NEREIDA wave power plant installed in the harbor of Mutriku in the northern Spanish shoreline constitutes an excellent example of this phenomenon. This article deals with the modeling, simulation and control of an oscillating water column unit within the NEREIDA wave power plant. The stalling behavior is investigated and two control strategies are proposed to avoid it. The first control approach is the airflow control which aims to adjust the airflow in the turbine duct using a proportional–integral–derivative controller tuned with the water cycle algorithm. The second control approach is the rotational speed control adjusting the rotor speed using the rotor-side converter of the back-to-back converter which is wired to the doubly fed induction generator. Results of comparative studies show a power generation improvement even relative to the real measured data.

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TANIGAKI, Yusuke, and Shogo MORIYUKI. "Oscillating Gene Expression Analysis by Long-term Sampling of Plant Factory Lettuce." Shokubutsu Kankyo Kogaku 32, no. 3 (2020): 160–64. http://dx.doi.org/10.2525/shita.32.160.

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Moulia, Bruno, Stéphane Douady, and Olivier Hamant. "Fluctuations shape plants through proprioception." Science 372, no. 6540 (April 22, 2021): eabc6868. http://dx.doi.org/10.1126/science.abc6868.

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Plants constantly experience fluctuating internal and external mechanical cues, ranging from nanoscale deformation of wall components, cell growth variability, nutating stems, and fluttering leaves to stem flexion under tree weight and wind drag. Developing plants use such fluctuations to monitor and channel their own shape and growth through a form of proprioception. Fluctuations in mechanical cues may also be actively enhanced, producing oscillating behaviors in tissues. For example, proprioception through leaf nastic movements may promote organ flattening. We propose that fluctuation-enhanced proprioception allows plant organs to sense their own shapes and behave like active materials with adaptable outputs to face variable environments, whether internal or external. Because certain shapes are more amenable to fluctuations, proprioception may also help plant shapes to reach self-organized criticality to support such adaptability.

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Shakya, S. K., E. M. Goss, N. S. Dufault, and A. H. C. van Bruggen. "Potential Effects of Diurnal Temperature Oscillations on Potato Late Blight with Special Reference to Climate Change." Phytopathology® 105, no. 2 (February 2015): 230–38. http://dx.doi.org/10.1094/phyto-05-14-0132-r.

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Global climate change will have effects on diurnal temperature oscillations as well as on average temperatures. Studies on potato late blight (Phytophthora infestans) development have not considered daily temperature oscillations. We hypothesize that growth and development rates of P. infestans would be less influenced by change in average temperature as the magnitude of fluctuations in daily temperatures increases. We investigated the effects of seven constant (10, 12, 15, 17, 20, 23, and 27°C) and diurnally oscillating (±5 and ±10°C) temperatures around the same means on number of lesions, incubation period, latent period, radial lesion growth rate, and sporulation intensity on detached potato leaves inoculated with two P. infestans isolates from clonal lineages US-8 and US-23. A four-parameter thermodynamic model was used to describe relationships between temperature and disease development measurements. Incubation and latency progression accelerated with increasing oscillations at low mean temperatures but slowed down with increasing oscillations at high mean temperatures (P < 0.005), as hypothesized. Infection efficiency, lesion growth rate, and sporulation increased under small temperature oscillations compared with constant temperatures but decreased when temperature oscillations were large. Thus, diurnal amplitude in temperature should be considered in models of potato late blight, particularly when predicting effects of global climate change on disease development.

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AOKI, I. "Entropy budgets of deciduous plant leaves and a theorem of oscillating entropy production." Bulletin of Mathematical Biology 49, no. 4 (1987): 449–60. http://dx.doi.org/10.1016/s0092-8240(87)80006-x.

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Falcão, A. F. de O. "Control of an oscillating-water-column wave power plant for maximum energy production." Applied Ocean Research 24, no. 2 (April 2002): 73–82. http://dx.doi.org/10.1016/s0141-1187(02)00021-4.

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Aoki, Ichiro. "Entropy budgets of deciduous plant leaves and a theorem of oscillating entropy production." Bulletin of Mathematical Biology 49, no. 4 (July 1987): 449–60. http://dx.doi.org/10.1007/bf02458862.

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Justino, P. A. P., and A. F. de O. Falca˜o. "Rotational Speed Control of an OWC Wave Power Plant." Journal of Offshore Mechanics and Arctic Engineering 121, no. 2 (May 1, 1999): 65–70. http://dx.doi.org/10.1115/1.2830079.

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The paper deals with the control of an oscillating water column wave energy plant, equipped with a Wells turbine driving a variable speed electric generator. The control of the plant is achieved by changing the electric torque through the power conditioning equipment. The control has to meet several requirements: rotational speed allowable range, energy quality, and allowable fluctuations in power delivered to the grid. On the other hand, the turbine is expected to perform efficiently, and so its rotational speed should approximately match the sea conditions (it should be higher in more energetic sea states). Three different control strategies are described. Results of numerical simulations are presented for two of them, and are found to satisfy the prescribed requirements.

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Tran, Daniel, Tiffanie Girault, Marjorie Guichard, Sébastien Thomine, Nathalie Leblanc-Fournier, Bruno Moulia, Emmanuel de Langre, Jean-Marc Allain, and Jean-Marie Frachisse. "Cellular transduction of mechanical oscillations in plants by the plasma-membrane mechanosensitive channel MSL10." Proceedings of the National Academy of Sciences 118, no. 1 (December 28, 2020): e1919402118. http://dx.doi.org/10.1073/pnas.1919402118.

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Plants spend most of their life oscillating around 1–3 Hz due to the effect of the wind. Therefore, stems and foliage experience repetitive mechanical stresses through these passive movements. However, the mechanism of the cellular perception and transduction of such recurring mechanical signals remains an open question. Multimeric protein complexes forming mechanosensitive (MS) channels embedded in the membrane provide an efficient system to rapidly convert mechanical tension into an electrical signal. So far, studies have mostly focused on nonoscillatory stretching of these channels. Here, we show that the plasma-membrane MS channel MscS-LIKE 10 (MSL10) from the model plant Arabidopsis thaliana responds to pulsed membrane stretching with rapid activation and relaxation kinetics in the range of 1 s. Under sinusoidal membrane stretching MSL10 presents a greater activity than under static stimulation. We observed this amplification mostly in the range of 0.3–3 Hz. Above these frequencies the channel activity is very close to that under static conditions. With a localization in aerial organs naturally submitted to wind-driven oscillations, our results suggest that the MS channel MSL10, and by extension MS channels sharing similar properties, represents a molecular component allowing the perception of oscillatory mechanical stimulations by plants.

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Gurnari, Luana, Pasquale G. F. Filianoti, Marco Torresi, and Sergio M. Camporeale. "The Wave-to-Wire Energy Conversion Process for a Fixed U-OWC Device." Energies 13, no. 1 (January 6, 2020): 283. http://dx.doi.org/10.3390/en13010283.

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Oscillating water column (OWC) devices, either fixed or floating, are the most common wave energy converter (WEC) devices. In this work, the fluid dynamic interaction between waves and a U-shaped OWC breakwater embedding a Wells turbine has been investigated through unsteady Computational Fluid Dynamic (CFD) simulations. The full-scale plant installed in the harbor of Civitavecchia (Italy) was numerically modeled. A two-dimensional domain was adopted to simulate the unsteady flow, both outside and inside the U-OWC device, including the air chamber and the oscillating flow inside the conduit hosting the Wells turbine. For the numerical simulation of the damping effect induced by the Wells turbine connected to the air chamber, a porous medium was placed in the computational domain, representing the conduit hosting the turbine. Several simulations were carried out considering periodic waves with different periods and amplitudes, getting a deep insight into the energy conversion process from wave to the turbine power output. For this purpose, the three main steps of the overall energy conversion process have been examined. Firstly, from the wave power to the power of the water oscillating flow inside the U-duct. Secondly, from the power of the oscillating water flow to the air pneumatic power. Finally, from the air pneumatic power to the Wells turbine power output. Results show that the U-OWC can capture up to 66% of the incoming wave power, in the case of a wave period close to the eigenperiod of the plant. However, only two-thirds of the captured energy flux is available to the turbine, being partially dissipated due to the losses in the U-duct and the air chamber. Finally, the overall time-average turbine power output is evaluated showing that it is strongly influenced by a suitable choice of the turbine characteristics (mainly geometry and rotational speed).

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Kircher, Stefan, and Peter Schopfer. "The plant hormone auxin beats the time for oscillating light-regulated lateral root induction." Development 145, no. 23 (November 2, 2018): dev169839. http://dx.doi.org/10.1242/dev.169839.

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M'zoughi, Fares, Izaskun Garrido, Aitor J. Garrido, and Manuel De La Sen. "ANN-Based Airflow Control for an Oscillating Water Column Using Surface Elevation Measurements." Sensors 20, no. 5 (February 29, 2020): 1352. http://dx.doi.org/10.3390/s20051352.

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Oscillating water column (OWC) plants face power generation limitations due to the stalling phenomenon. This behavior can be avoided by an airflow control strategy that can anticipate the incoming peak waves and reduce its airflow velocity within the turbine duct. In this sense, this work aims to use the power of artificial neural networks (ANN) to recognize the different incoming waves in order to distinguish the strong waves that provoke the stalling behavior and generate a suitable airflow speed reference for the airflow control scheme. The ANN is, therefore, trained using real surface elevation measurements of the waves. The ANN-based airflow control will control an air valve in the capture chamber to adjust the airflow speed as required. A comparative study has been carried out to compare the ANN-based airflow control to the uncontrolled OWC system in different sea conditions. Also, another study has been carried out using real measured wave input data and generated power of the NEREIDA wave power plant. Results show the effectiveness of the proposed ANN airflow control against the uncontrolled case ensuring power generation improvement.

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Saad, Mina, Bruno Pereiras, José González, Jesús M. Fernández Oro, and Manuel García Díaz. "Performance Curve of a Radial Flow Turbine for an OWC Plant." Proceedings 2, no. 23 (November 7, 2018): 1413. http://dx.doi.org/10.3390/proceedings2231413.

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In this article, the performance of a radial flow turbine is determined in the framework of oscillating water column installations (OWC). The studied turbine redesigned and adapted from previous studies to this application, is analyzed in detail using CFD Fluent v16.2 and TurboGrid for mesh preprocessing. In particular, a 3D numerical model with high-quality hexahedral meshes (necessary to analyze the unsteady phenomena in the blade passages of the turbine) has been developed to obtain an enhanced prediction of the flow patterns. The results obtained through a full unsteady RANS resolution of the viscous and three-dimensional flow structures reveal the optimal performance of the radial turbine and confirm the expected improvements introduced during the redesign of the machine.

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de O. Falca˜o, A. F., L. C. Vieira, P. A. P. Justino, and J. M. C. S. Andre´. "By-Pass Air-Valve Control of an OWC Wave Power Plant." Journal of Offshore Mechanics and Arctic Engineering 125, no. 3 (July 11, 2003): 205–10. http://dx.doi.org/10.1115/1.1576815.

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The paper deals with the numerical simulation of the performance of an oscillating-water-column (OWC) wave power plant equipped with a by-pass valve whose role is to prevent the turbine flow rate from exceeding the stall-free operating conditions. Continuous and step-wise valve area changes are considered, the second case corresponding to multi-element design. The adequacy of the valve and of its control is assessed through the gain in annual electrical energy and the total number of required valve strokes. The following items are separately analyzed: (i) number of (identical) valve elements; (ii) valve response time; (iii) signal noise level in chamber air-pressure measurements due to large-eddy turbulence; (iv) valve’s control algorithm.

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Chen, Zhe, Xu Dong Li, Shao Guang Shi, Hong Zhi Jiang, and Hui Jie Zhao. "Structured-Light Based Rapid 3D Measurement of Plant Canopy Structure." Applied Mechanics and Materials 701-702 (December 2014): 549–53. http://dx.doi.org/10.4028/www.scientific.net/amm.701-702.549.

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Density three dimensional plant canopy structure data has numerous applications in agriculture, but many existing 3D data collection approaches are time-consuming. In this paper, we present a measurement system based on structured-light for plant canopy structure data collection. The structured-light projector projects laser beam reflected by dual-oscillating mirror, arrives to the plant canopy, which is captured by a camera. We propose a new scanning mode, that is, during one exposure time of CCD camera, one mirror keeps moving in high frequency and small angle, while the other one maintains the same position, so that we can get a laser stripe rather than a spot in each image, from which about 100 sub-pixel centers of laser stripe can be extracted. Experiments show that the measurement system can rapid collect three dimensional information of the plant.

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Jiang, Genshan, Weilong Xu, Yuechao Liu, Yapan Wu, and Qian Kong. "A Numerical Study on the Oscillating Flow Induced by an Acoustic Field around Coal Particles." Journal of Combustion 2016 (2016): 1–13. http://dx.doi.org/10.1155/2016/8306839.

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In order to investigate the acoustically driven oscillating flow around coal particles in the power plant boiler, the two-dimensional, unsteady mass and momentum conservation equations for laminar flow in spherical coordinates are developed numerically. The velocity field, axial pressure gradient, shear stress, and flow separation angle on the particle surface are carefully analyzed with different values of acoustic Reynolds number and Strouhal number. The minimum frequency required for flow separation is also investigated with different SPL (sound pressure level). The axial pressure gradient, shear stress, and separation angle on the surface are proportional to the magnitude of the oscillating flow velocity at low frequency (~50 Hz). However, those physical quantities have different values at high frequency (~5000 Hz), due to the combined effect of curvature and the flow acceleration.

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Otaola, Erlantz, Aitor J. Garrido, Jon Lekube, and Izaskun Garrido. "A Comparative Analysis of Self-Rectifying Turbines for the Mutriku Oscillating Water Column Energy Plant." Complexity 2019 (January 23, 2019): 1–14. http://dx.doi.org/10.1155/2019/6396904.

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Oscillating Water Column (OWC) based devices are arising as one of the most promising technologies for wave energy harnessing. However, the most widely used turbine comprising its power take-off (PTO) module, the Wells turbine, presents some drawbacks that require special attention. Notwithstanding different control strategies are being followed to overcome these issues; the use of other self-rectifying turbines could directly achieve this goal at the expense of some extra construction, maintenance, and operation costs. However, these newly developed turbines in turn show diverse behaviours that should be compared for each case. This paper aims to analyse this comparison for the Mutriku wave energy power plant.

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Cvejn, Jan, and Damir Vrančić. "The magnitude optimum tuning of the PID controller: Improving load disturbance rejection by extending the controller." Transactions of the Institute of Measurement and Control 40, no. 5 (February 1, 2017): 1669–80. http://dx.doi.org/10.1177/0142331216688749.

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The Magnitude Optimum (MO) tuning method for PID controllers, applied on stable and non-oscillating plants, usually gives fast tracking responses and offers very good process output disturbance-rejection performance, even if the process contains significant dead time. On the other hand, when an exogenous disturbance affects the process indirectly, for example, via the plant input, slow disturbance rejection responses may be obtained. The paper proposes a way of removing this problem by means of adding two first-order filters into the control loop, without modifying the controller parameters. The filter parameters are determined so that the disturbance lag is partially compensated and the stability margin properties of the MO tuning are preserved.

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Fan, Sufang, Fengzu Zhang, Shaowen Liu, Chuanshan Yu, Di Guan, and Canping Pan. "Removal of aflatoxin B1 in edible plant oils by oscillating treatment with alkaline electrolysed water." Food Chemistry 141, no. 3 (December 2013): 3118–23. http://dx.doi.org/10.1016/j.foodchem.2013.06.013.

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Henriques, J. C. C., J. J. Cândido, M. T. Pontes, and A. F. O. Falcão. "Wave energy resource assessment for a breakwater-integrated oscillating water column plant at Porto, Portugal." Energy 63 (December 2013): 52–60. http://dx.doi.org/10.1016/j.energy.2013.09.063.

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McKenna, Sylvester T., Joseph G. Kunkel, Maurice Bosch, Caleb M. Rounds, Luis Vidali, Lawrence J. Winship, and Peter K. Hepler. "Exocytosis Precedes and Predicts the Increase in Growth in Oscillating Pollen Tubes." Plant Cell 21, no. 10 (October 2009): 3026–40. http://dx.doi.org/10.1105/tpc.109.069260.

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Hanson, Kenneth R. "Steady-State and Oscillating Photosynthesis by a Starchless Mutant of Nicotiana sylvestris." Plant Physiology 93, no. 3 (July 1, 1990): 1212–18. http://dx.doi.org/10.1104/pp.93.3.1212.

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Künne, A., and E. J. De Groot. "Protein Synthesis inEuglena gracilisis Light-and Temperature-Dependent, Oscillating in a Circadian, Temperature-Compensated Manner." Botanica Acta 109, no. 1 (February 1996): 57–63. http://dx.doi.org/10.1111/j.1438-8677.1996.tb00870.x.

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Setiyawan, Erwin Affandi, and Lisa Arnita Anzar. "Study on Wave Energy Conversion by Using Oscillating Water Column in Alindau Waters." MATEC Web of Conferences 331 (2020): 03001. http://dx.doi.org/10.1051/matecconf/202033103001.

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Growth electricity consumption in central sulawesi encourages increased utilization of conventional resources such as petroleum products and coal as alternative energy plant. It causes some adverse effect either on the environment, health and economy. As a result, the alternative of conversion energy from non-conventional resources must be provided. Central Sulawesi with coastline about 4,013km has immense potential in developing wave energy as an alternative of Renewable Energy Resource. This paper investigated the potential for wave energy conversion in Lindau Water as an alternative of power plant by using Oscillating Water Column System (OWC). The value of significant wave height and periods are calculated based on the Wilson method, which is then analysed to determine the potential of electricity that feasible converted from wave energy in Lindau waters and potential to applicated wave energy conversion using OWC in Lindau Waters. The result found the conversion of Lindau waters wave energy produce the largest power that can be converted is about 21. 000 watts. Its shows the potential that can be applied to coverage the need electricity by using wave energy in Alindau Village.

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Pawitan, Krisna Adi, Ben Gossling, William Allsop, and Tom Bruce. "VIOLENT IN-CHAMBER LOADS IN AN OSCILLATING WATER COLUMN CAISSON." Coastal Engineering Proceedings, no. 36 (December 30, 2018): 11. http://dx.doi.org/10.9753/icce.v36.structures.11.

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In 2009, four of 16 chambers in the Mutriku breakwater-integrated Oscillating Water Column (OWC) were badly damaged by storms, probably due to breaking wave loads, and slam within the chamber. To minimize exposure of future plant to such risks, it is necessary to characterise wave conditions under which such an installation could experience impact loads. This characterisation can be crucial to controling the power-take off resistance to increase the survability of the device during extreme weather. Large scale physical model tests in the Grosse Wellenkanal (GWK) included a video camera installed inside the chamber facing the rear chamber wall. Pressure sensors in the ceiling of the chamber were utilised to quantify the water loads. In-chamber impact pressures of up to 8 ÏgH were recorded on the chamber ceiling, associated with the â€˜sloshingâ€™ observed. The â€œsloshingâ€ phenomenon is not uncommon and should be considered in design processes.

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Sirvydas, Algimantas, Vidmantas Kučinskas, Paulius Kerpauskas, Jūratė Nadzeikienė, and Albinas Kusta. "SOLAR RADIATION ENERGY PULSATIONS IN A PLANT LEAF." JOURNAL OF ENVIRONMENTAL ENGINEERING AND LANDSCAPE MANAGEMENT 18, no. 3 (September 30, 2010): 188–95. http://dx.doi.org/10.3846/jeelm.2010.22.

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Solar radiation energy is used by vegetation, which predetermines the existence of biosphere. The plant uses 1–2% of the absorbed radiant energy for photosynthesis. All the remaining share of the absorbed energy, accounting for 99–98%, converts into thermal energy in the plant leaf. At the lowest wind under natural surrounding air conditions, plant leaves change their position with respect to the Sun. An oscillating plant leaf receives a variable amount of solar radiation energy, which causes changes in the balance of plant leaf energies and a changing emission of heat in the leaf. The analysis of solar radiation energy pulsations in the plant leaf shows that when the leaf is in the edge positions of angles 10°, 20° and 30° with respect to the Sun, 1.5%; 6% and 13% less of radiation energy reach the leaf, respectively. During periodic motion, when the amplitude of leaf oscillation is no bigger than 10°, the plant surface receives up to 1.6% less of solar radiation energy within a certain period of time, and when the amplitude of oscillation reaches 30° up to 14% less of solar radiation energy reach the leaf surface. The total amount of radiant energy received during pulsations of solar radiation energy is not dependent on the frequency of oscillation in the same interval of time. Temperature pulsations occur in the leaf due to solar radiation energy pulsations when the plant leaf naturally changes its position with respect to the Sun. Santrauka Saules spinduliuotes energija būtina augalijai, kuri lemia biosferos egzistavima. Augalas 1–2 % absorbuotos spinduliuotes energijos sunaudoja fotosintezei, o 99–98 % absorbuotos energijos augalo lape virsta šilumine energija. Natūraliomis aplinkos salygomis esant mažiausiam vejui augalo lapu padetis Saules atžvilgiu keičiasi. Taigi augalo svyruojančio lapo gaunamas Saules spinduliuotes energijos kiekis yra kintamas, tai sukelia pokyčius augalo lapo energiju balanse ir kintama šilumos išsiskyrima lape. Analizuojant Saules spinduliuotes energijos pulsacijas augalo lape, nustatyta, kad, lapui esant kraštinese 10°, 20° ir 30° kampu padetyse Saules atžvilgiu, i ji atitinkamai patenka 1,5 %; 6 % ir 13 % mažiau spinduliuotes energijos. Augalo lapui periodiškai svyruojant, kai svyravimo amplitude yra iki 10°, per tam tikra laika i lapo paviršiu patenka iki 1,6 % mažiau Saules spinduliuotes energijos, o kai svyravimo amplitu‐de siekia iki 30°, – iki 14 % mažiau. Saules spinduliuotes energijos pulsaciju metu gautas bendras spinduliuotes energijos kiekis nepriklauso nuo to paties laiko intervalo svyravimo dažnio. Del Saules spinduliuotes energijos pulsaciju, natūraliai keičiantis augalo lapo padečiai Saules atžvilgiu, lape kyla temperatūros pulsacijos. Резюме Растения потребляют солнечную лучевую энергию, которая является основой существования биосферы. 1–2% абсорбированной лучевой энергии они используют на фотосинтез. В натуральных условиях при малейшем дуновении ветра листья растений меняют свое положение относительно Солнца. Колеблющийся лист получает переменное количество лучевой энергии, которое вызывает изменения в энергетическом балансе листа растения, что сказывается на переменном выделении тепла в листе. Анализируя пульсации солнечной лучевой энергии в листе растения, установлено, что при крайних положениях листа относительно Солнца на 10, 20 и 30 градусов на лист попадает соответственно на 1,5%, 6% и 13% меньше лучевой энергии. При периодическом колебании листа, когда амплитуда его колебания составляет 10 градусов, за известный промежуток времени солнечная лучевая энергия, попадающая на поверхность листа, уменьшается до 1,6%, а при амплитуде колебания до 30 градусов соответственно количество лучевой энергии на поверхности листа растения уменьшается до 14%. Установлено, что суммарное количество солнечной лучевой энергии во время пульсации не зависит от частоты колебания листа за одинаковый промежуток времени. Пульсации солнечной лучевой энергии при изменении положения листа растения относительно Солнца вызывают температурные пульсации в листе.

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Shtengelov, R. S., E. A. Filimonova, and I. S. Shubin. "Analysis of multi-well pumpingtest under atmosphere pressure and anisochronous schedule of pumping rate." Moscow University Bulletin. Series 4. Geology, no. 3 (June 28, 2017): 50–58. http://dx.doi.org/10.33623/0579-9406-2017-3-50-58.

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Interpretation problems of long-term anisochronous multi-well pumping test under oscillating atmosphere pressure is analyzed. The barometric efficiency and corrections of measured drawdowns are calculated to Udomlya groundwater basin, evaluation of space and temporal moving of depression cone is investigated. Obtained hydraulic parameters is used for numerical model of groundwater basin and forecasting of periodical compensation wells pumping for recharge lake-coolers of Kalininskaya Nuclear Power Plant.

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Sheriff, DW. "Why Did the Apparent Hydraulic Conductance of Plants Oscillate for Passioura and Tanner?" Functional Plant Biology 14, no. 4 (1987): 475. http://dx.doi.org/10.1071/pp9870475.

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When using an apparatus to keep constant the position of the meniscus at the end of a cut petiole of phosphorus-deficient plants, Passioura and Tanner [Aust. J. Plant Physiol.12, 455-61 (1985)] observed oscillations in the applied balancing pressure. They ascribed these to oscillations in the hydraulic con- ductance of the plant. Their results are re-examined using an electric analogue, and it is suggested that oscillations resulted from the combination of hydraulic resistance and capacitance in the plant in conjunction with the apparatus they used. Measurement of the hydraulic resistance and of the period of oscillation makes possible an estimate of the hydraulic capacitance of the plant.

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Curran, R., T. P. Stewart, and T. J. T. Whittaker. "Design synthesis of oscillating water column wave energy converters: Performance matching." Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 211, no. 6 (September 1, 1997): 489–505. http://dx.doi.org/10.1243/0957650981537375.

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The matching of a Wells air turbine to an oscillating water column (OWC) is addressed, with particular reference to design synthesis at the Islay prototype wave power converter. The level of damping applied by the turbine must optimize the hydraulic performance of the OWC in order to facilitate efficient conversion from wave power to pneumatic power. Furthermore, a Wells turbine is only able to convert pneumatic power to mechanical power over a limited range of flow coefficients. Therefore, the efficient operational range of the turbine must extend over a sufficient and optimal proportion of the range of flow coefficients generated by the OWC. Suitable analytical models that describe the behaviour of the system are presented and subsequently the wave conditions and conversion performance at the Islay plant are outlined in order to exemplify the design synthesis to be achieved.

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Delauré, Y. M. C., and A. Lewis. "3D hydrodynamic modelling of fixed oscillating water column wave power plant by a boundary element methods." Ocean Engineering 30, no. 3 (February 2003): 309–30. http://dx.doi.org/10.1016/s0029-8018(02)00032-x.

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Fabrikant, A. L. "Harbour oscillations generated by shear flow." Journal of Fluid Mechanics 282 (January 10, 1995): 203–17. http://dx.doi.org/10.1017/s0022112095000103.

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A new mechanism that could be responsible for excitation of long-period oscillations in partially enclosed harbours is discussed. This mechanism is based on the interaction between a shear flow and the harbour-basin natural mode and does not suppose any external exciting forces caused by wind waves, tsunami, etc. The growth rate of harbour oscillations is found in terms of a plane-wave reflection coefficient integrated on the wavenumber spectrum of the oscillating outflow field near the harbour entrance. Analytical considerations for simple shear flows (vortex sheet and jet) show that the growth rate changes its sign depending on the ratio of oscillation frequency to flow speed.

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Barambones, Oscar, Jose Gonzalez de Durana, and Isidro Calvo. "Adaptive Sliding Mode Control for a Double Fed Induction Generator Used in an Oscillating Water Column System." Energies 11, no. 11 (October 27, 2018): 2939. http://dx.doi.org/10.3390/en11112939.

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Wave power conversion systems are nonlinear dynamical systems that must endure strong uncertainties. Efficiency is a key issue for these systems, and the application of robust control algorithms can improve it considerably. Wave power generation plants are typically built using variable speed generators, such as the doubly fed induction generator (DFIG). These generators, compared with fixed speed generators, are very versatile since the turbine speed may be adjusted to improve the efficiency of the whole system. Nevertheless, a suitable speed controller is required for these systems, which must be able to avoid the stalling phenomenon and track the optimal reference for the turbine. This paper proposes a sliding mode control scheme aimed at oscillating water column (OWC) generation plants using Wells turbines and DFIGs. The contributions of the paper are (1) an adaptive sliding mode control scheme that does not require calculating the bounds of the system uncertainties, (2) a Lyapunov analysis of stability for the control algorithm against system uncertainties and disturbances, and (3) a validation of the proposed control scheme through several simulation examples with the Matlab/Simulink suite. The performance results, obtained by means of simulations, for a wave power generation plant (1) evidence that this control scheme improves the power generation of the system and (2) prove that this control scheme is robust in the presence of disturbances.

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Hashimoto, Takashi. "Molecular genetic analysis of left–right handedness in plants." Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences 357, no. 1422 (June 29, 2002): 799–808. http://dx.doi.org/10.1098/rstb.2002.1088.

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Handedness in plant growth may be most familiar to us when we think of tendrils or twining plants, which generally form consistent right– or left–handed helices as they climb. The petals of several species are sometimes arranged like fan blades that twist in the same direction. Another less conspicuous example is ‘circumnutation’, the oscillating growth of axial organs, which alternates between a clockwise and an anti–clockwise direction. To unravel molecular components and cellular determinants of handedness, we screened Arabidopsis thaliana seedlings for helical growth mutants with fixed handedness. Recessive spiral1 and spiral2 mutants show right–handed helical growth in roots, hypocotyls, petioles and petals; semi–dominant lefty1 and lefty2 mutants show opposite left–handed growth in these organs. lefty mutations are epistatic to spiral mutations. Arabidopsis helical growth mutants with fixed handedness may be impaired in certain aspects of cortical microtubule functions, and characterization of the mutated genes should lead us to a better understanding of how microtubules function in left–right handedness in plants.

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Manor, Yair, John Rinzel, Idan Segev, and Yosef Yarom. "Low-Amplitude Oscillations in the Inferior Olive: A Model Based on Electrical Coupling of Neurons With Heterogeneous Channel Densities." Journal of Neurophysiology 77, no. 5 (May 1, 1997): 2736–52. http://dx.doi.org/10.1152/jn.1997.77.5.2736.

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Manor, Yair, John Rinzel, Idan Segev, and Yosef Yarom. Low-amplitude oscillations in the inferior olive: a model based on electrical coupling of neurons with heterogeneous channel densities. J. Neurophysiol. 77: 2736–2752, 1997. The mechanism underlying subthreshold oscillations in inferior olivary cells is not known. To study this question, we developed a single-compartment, two-variable, Hodgkin-Huxley-like model for inferior olive neurons. The model consists of a leakage current and a low-threshold calcium current, whose kinetics were experimentally measured in slices. Depending on the maximal calcium and leak conductances, we found that a neuron model's response to current injection could be of four qualitatively different types: always stable, spontaneously oscillating, oscillating with injection of current, and bistable with injection of current. By the use of phase plane techniques, numerical integration, and bifurcation analysis, we subdivided the two-parameter space of channel densities into four regions corresponding to these behavioral types. We further developed, with the use of such techniques, an empirical rule of thumb that characterizes whether two cells when coupled electrically can generate sustained, synchronized oscillations like those observed in inferior olivary cells in slices, of low amplitude (0.1–10 mV) in the frequency range 4–10 Hz. We found that it is not necessary for either cell to be a spontaneous oscillator to obtain a sustained oscillation. On the other hand, two spontaneous oscillators always form an oscillating network when electrically coupled with any arbitrary coupling conductance. In the case of an oscillating pair of electrically coupled nonidentical cells, the coupling current varies periodically and is nonzero even for very large coupling values. The coupling current acts as an equalizing current to reconcile the differences between the two cells' ionic currents. It transiently depolarizes one cell and/or hyperpolarizes the other cell to obtain the regenerative response(s) required for the synchronized oscillation. We suggest that the subthreshold oscillations observed in the inferior olive can emerge from the electrical coupling between neurons with different channel densities, even if the inferior olive nucleus contains no or just a small proportion of spontaneously oscillating neurons.

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Vesjolaja, Ludmila, Bjørn Glemmestad, and Bernt Lie. "Double-Loop Control Structure for Rotary Drum Granulation Loop." Processes 8, no. 11 (November 8, 2020): 1423. http://dx.doi.org/10.3390/pr8111423.

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The operation of granulation plants on an industrial scale is challenging. Periodic instability associated with the operation of the granulation loop causes the particle size distribution of the particles flowing out from the granulator to oscillate, thus making it difficult to maintain the desired product quality. To address this problem, two control strategies are proposed in this paper, including a novel approach, where product-sized particles are recycled back to maintain a stable granulation loop process. A dynamic model of the process that is based on a population balance equation is used to represent the process dynamics. Both of the control strategies utilize a double-loop control structure that is suitable for highly oscillatory systems. The simulation results show that both control strategies, including the novel approach, are able to remove the oscillating behaviour and stabilize the granulation plant loop.

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Freudenmann, Thomas, Hans-Joachim Gehrmann, Krasimir Aleksandrov, Mohanad El-Haji, and Dieter Stapf. "Hybrid Models for Efficient Control, Optimization, and Monitoring of Thermo-Chemical Processes and Plants." Processes 9, no. 3 (March 12, 2021): 515. http://dx.doi.org/10.3390/pr9030515.

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This paper describes a procedure and an IT product that combine numerical models, expert knowledge, and data-based models through artificial intelligence (AI)-based hybrid models to enable the integrated control, optimization, and monitoring of processes and plants. The working principle of the hybrid model is demonstrated by NOx reduction through guided oscillating combustion at the pulverized fuel boiler pilot incineration plant at the Institute for Technical Chemistry, Karlsruhe Institute of Technology. The presented example refers to coal firing, but the approach can be easily applied to any other type of nitrogen-containing solid fuel. The need for a reduction in operation and maintenance costs for biomass-fired plants is huge, especially in the frame of emission reductions and, in the case of Germany, the potential loss of funding as a result of the Renewable Energy Law (Erneuerbare-Energien-Gesetz) for plants older than 20 years. Other social aspects, such as the departure of experienced personnel may be another reason for the increasing demand for data mining and the use of artificial intelligence (AI).

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Enaibe, Edison A., Akpata Erhieyovwe, and Osafile E. Omosede. "THEORETICAL MECHANICS OF 6-DIMENSIONAL (6D) CENTRAL-FORCE MOTION WITH TANGENTIAL OSCILLATIONS." JOURNAL OF ADVANCES IN NATURAL SCIENCES 1, no. 1 (August 12, 2014): 22–33. http://dx.doi.org/10.24297/jns.v1i1.382.

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The relevance of the Central - force motion in the macroscopic and microscopic frames warrants a detailed study of the theoretical mechanics associated with it. So far, researchers have only considered central - force motion, as motion only in the translational and rotational elliptical plane with polar coordinates. However, the theoretical knowledge advanced by these researchers in line with this type of motion is scientifically restricted as several possibilities are equally applicable. In order to make the mechanics of a Central - force motion sufficiently meaningful, we have in this work extended the theory which has only been that of translational and rotational in the elliptical plane, by including fictitious radii and spin oscillations of the body about the axis of rotation. In this work, we used the methods of Newtonian mechanics to establish the new central-force field obeyed by the motion of a body, when the effect of spin oscillation is added. The new central-force field comprises of the radial accelerations, translational orbital angular velocity and the oscillating spin angular velocities. The energy conveyed in the spin oscillating phase increases as the orbital oscillating angles above or below the horizon of the elliptical plane is increased.

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Journal articles on the topic 'Oscillating plant'

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