Irrigation dose according to substrate characteristics, in hydroponic systems

2015 ◽  
Vol 1 (1) ◽  
Author(s):  
Giorgos N. Mavrogianopoulos
Keyword(s):  
Salt Concentration ◽  
Theoretical Study ◽  
Control Method ◽  
Low Cost ◽  
Irrigation Frequency ◽  
Irrigation Solution ◽  
Leaching Fraction ◽  
Irrigation Control ◽  
Hydroponic Systems ◽  
Water Holding

AbstractThe correct supply of water and nutrients is very important in hydroponic growing systems in order to use water and fertilizers efficiently and avoid stress situations. Usually, in low-cost hydroponic greenhouses using open hydroponic systems, the supply of water and nutrients is performed with a constant irrigation frequency, changing the dose to ensure that each irrigation cycle (each day) delivers the amount of nutrient solution needed for the plants, plus an additional 20 to 30% leaching fraction. This type of irrigation control may result in suboptimal conditions in many periods of time, although the total amount of irrigation solution supplied to the crop may be much larger than required. For an efficient irrigation the present theoretical study proposes that in open hydroponic systems there is a significant possibility to preserve water and nutrients, by shifting the irrigation control from a changeable irrigation dose according to evapotranspiration to an irrigation dose calculated according to the amount of used substrate in the bag, the characteristics of the substrate and the salt concentration of used water. The frequency of irrigation is recommended to be performed according to evapotranspiration. The proposed irrigation control is more rational than the currently used control method as it takes into account the characteristics on water holding capacity of the used substrates, resulting to a conservation of fertilizers and water.

scholarly journals Preparation of Organic Crystal Seed and Its Application in Improving the Functional Period of Biodegradable Agricultural Film

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 826
Author(s):  
Runmeng Qiao ◽  
Xin Wang ◽  
Guangjiong Qin ◽  
Qi Liu ◽  
Jialei Liu ◽  
...  
Keyword(s):  
Degradation Rate ◽  
Low Cost ◽  
Water Vapor Permeability ◽  
Growth Period ◽  
Nucleating Agent ◽  
Degree Of Crystallinity ◽  
Vapor Permeability ◽  
Agricultural Films ◽  
Degradation Degree ◽  
Water Holding

White pollution caused by agricultural films has recently attracted great attention. In some areas, the content of micro plastic in the soil has reached 30 kg/ha. The most effective way to solve this problem is to replace traditional polyethylene agricultural films with degradable agricultural films. The consistency between the degradation rate and the crop growth period has become the biggest obstacle for the wide application of such novel agricultural films. In this paper, crystallinity regulation is used to adjust the functional period of degradable agricultural films. In addition, an organic nucleating agent of polyethylenimine (PEI) is selected by doping it to poly(butylene adipate-co-terephthalate) (PBAT) polymers using a double-screw extruder. The PBAT doped with 1 wt% PEI films revealed a significant increase in mechanical properties, water holding capacity, and crystallinity compared with the pure PBAT film. There was a 31.9% increase in tensile strength, a 30.5% increase in elongation at break, a 29.6% increase in tear resistance, a 30.9% decrease in water vapor permeability, and a 3.1% increase in crystallinity. Furthermore, the induction period of PBAT doped with 1 wt% PEI under photoaging (without soil) was about 160 h longer than PBAT film, and the experienced biodegradation in soil (without light) was 1 week longer than PBAT film. Experimental results exhibited that the change of degradation degree was linearly proportional to the degree of crystallinity. This study proposes a convenient, low-cost, and effective method to adjust the crystallinity and change the degradation rate.

Energy Absorption of Origami Crash Box: Numerical Simulation and Theoretical Analysis

2018 ◽  
Author(s):  
Mengyan Shi ◽  
Jiayao Ma ◽  
Yan Chen ◽  
Zhong You
Keyword(s):  
Energy Absorption ◽  
Theoretical Study ◽  
Low Cost ◽  
Deformation Mode ◽  
Absorption Efficiency ◽  
Great Promise ◽  
Good Match ◽  
Energy Absorption Efficiency ◽  
Thin Walled ◽  
Initial Peak

Thin-walled tubes as energy absorption devices are widely in use for their low cost and high manufacturability. Employing origami technique on a tube enables induction of a predetermined failure mode so as to improve its energy absorption efficiency. Here we study the energy absorption of a hexagonal tubular device named the origami crash box numerically and theoretically. Numerical simulations of the quasi-static axial crushing show that the pattern triggers a diamond-shaped mode, leading to a substantial increase in energy absorption and reduction in initial peak force. The effects of geometric parameters on the performance of the origami crash box are also investigated through a parametric study. Furthermore, a theoretical study on the deformation mode and energy absorption of the origami crash box is carried out, and a good match with numerical results is obtained. The origami crash box shows great promise in the design of energy absorption devices.

scholarly journals A New Control Method for Vibration and Noise Suppression in Switched Reluctance Machines

Energies ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1554 ◽  
Author(s):  
Man Zhang ◽  
Imen Bahri ◽  
Xavier Mininger ◽  
Cristina Vlad ◽  
Hongqin Xie ◽  
...  
Keyword(s):  
Control Strategy ◽  
Noise Suppression ◽  
Control Method ◽  
Negative Impact ◽  
Low Cost ◽  
Radial Force ◽  
Torque Control ◽  
Transient Condition ◽  
Switched Reluctance ◽  
Switched Reluctance Machines

Due to their inherent advantages such as low cost, robustness and wide speed range, switched reluctance machines (SRMs) have attracted great attention in electrical vehicles. However, the vibration and noise problems of SRMs limit their application in the automotive industry because of the negative impact on driver and passengers’ comfort. In this paper, a new control method is proposed to improve the vibratory and acoustic behavior of SRMs. Two additional control blocks —direct force control (DFC) and reference current adapter (RCA)—are introduced to the conventional control method (average torque control (ATC)) of SRM. DFC is adopted to control the radial force in the teeth of the stator, since the dynamic of the radial force has a large impact on the vibratory performance. RCA is proposed to handle the trade-off between the DFC and ATC. It produces an auto-tuning current reference to update the reference current automatically depending on the control requirement. The effectiveness of the proposed control strategy is verified by experimental results under both steady and transient condition. The results show that the proposed method improves the acoustic performance of the SRM and maintains the dynamic response of it, which proves the potential of the proposed control strategy.

scholarly journals Design and multichannel electromyography system-based neural network control of a low-cost myoelectric prosthesis hand

2021 ◽  
Vol 12 (1) ◽  
pp. 69-83
Author(s):  
Saygin Siddiq Ahmed ◽  
Ahmed R. J. Almusawi ◽  
Bülent Yilmaz ◽  
Nuran Dogru
Keyword(s):  
Neural Network ◽  
Control Method ◽  
Low Cost ◽  
Hand Movement ◽  
Cost Effective ◽  
Network Control ◽  
Human Hand ◽  
Prosthetic Hand ◽  
Myoelectric Prosthesis ◽  
System File

Abstract. This study introduces a new control method for electromyography (EMG) in a prosthetic hand application with a practical design of the whole system. The hand is controlled by a motor (which regulates a significant part of the hand movement) and a microcontroller board, which is responsible for receiving and analyzing signals acquired by a Myoware muscle device. The Myoware device accepts muscle signals and sends them to the controller. The controller interprets the received signals based on the designed artificial neural network. In this design, the muscle signals are read and saved in a MATLAB system file. After neural network program processing by MATLAB, they are then applied online to the prosthetic hand. The obtained signal, i.e., electromyogram, is programmed to control the motion of the prosthetic hand with similar behavior to a real human hand. The designed system is tested on seven individuals at Gaziantep University. Due to the sufficient signal of the Mayo armband compared to Myoware sensors, Mayo armband muscle is applied in the proposed system. The discussed results have been shown to be satisfactory in the final proposed system. This system was a feasible, useful, and cost-effective solution for the handless or amputated individuals. They have used the system in their day-to-day activities that allowed them to move freely, easily, and comfortably.

scholarly journals Design of Orbit Controls for a Multiple CubeSat Mission Using Drift Rate Modulation

Aerospace ◽  
2021 ◽  
Vol 8 (11) ◽  
pp. 323
Author(s):  
Youngbum Song ◽  
Sang-Young Park ◽  
Geuk-Nam Kim ◽  
Dong-Gu Kim
Keyword(s):  
Drift Rate ◽  
Time Synchronization ◽  
Control Method ◽  
Low Cost ◽  
Relative Distance ◽  
Laser Communication ◽  
Surveillance Systems ◽  
Rate Modulation ◽  
Orbit Control ◽  
Orbital Drift

For the low-cost improvement of laser communication, which is critical for various applications such as surveillance systems, a study was conducted on relative distance control based on orbital drift rate modulations for multiple CubeSats during formation flying. The VISION mission covered in this paper comprises two CubeSats to demonstrate laser communication technology in space. During the mission, the deputy CubeSat changes the relative distance to execute mission objectives within various scenarios. Impulsive controls decrease, maintain, and increase the relative distance between the CubeSats by changing the orbital drift rates. The simulation results indicated that the desired orbital operation can be conducted within a given ΔV budget. In addition, the errors in the orbit determination, thrust maneuvers, and time synchronization were analyzed to satisfy the mission requirements. The mass-to-area ratio should be matched to adjust the relative distance between satellites with different properties by drift rate modulation. The proposed orbit control method appropriately operated the VISION mission by adjusting the drift rate modulation. The results of this study serve as a basis for the development of complex orbit control simulations and detailed designs that reflect the characteristics of the thrust module and operational aspects.

Delivering More Fit-for-Purpose Wells with Low Cost Approach at Untapped Area Matured Field – Application of Cone Concept Statistical Approach

2021 ◽  
Author(s):  
M. Hatta M. Yusof ◽  
M. Zarkashi Sulaiman ◽  
Rahimah A. Halim ◽  
Nurfaridah Ahmad Fauzi ◽  
Ahgheelan Sella Thurai ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
Statistical Approach ◽  
Control Method ◽  
Low Cost ◽  
Volatile Oil ◽  
Field Application ◽  
Well Design ◽  
Execution Phase ◽  
Sand Control ◽  
Fit For Purpose

Abstract This paper discusses the Case study of Field A in offshore Sarawak, Malaysia which focus on re-thinking development based on statistical analysis of the fields. Conventionally, well design is driven by subsurface requirement by targeting the high-reserve sand and well is designed to meet subsurface objectives. However, the conventional way may not be efficient to develop matured field environment due to the high CAPEX and the inconsistencies among well design especially in current volatile oil price period. The objective of this fit-for-purpose approach which is called "Cone Concept Statistical Approach" is to steer away from the conventional way of targeting only sweet spots whilst leaving the remaining potential resources undeveloped. Based on the statistical analysis and subsurface fields pattern, the "Cone Concept Statistical Approach" in which standardizing well design and trajectories was developed to extract the whole fields’ reserve at maximum. Well design boundaries were introduced to ensure this approach can be replicated throughout the field. Not only this study covers drilling perspective, completion perspective was also taken into consideration by exploring a cheaper and fit for purpose sand control method, considering it is a matured field with relatively short remaining field life. The Well Cost Catalogue for this field-specific approach was also developed which contains different types of design and completion, in order to holistically evaluate sand control method and identify the best option for the project moving forward. This "Cone Concept Statistical Approach" aims to enable operator to drill simple wells within the same allocated budget in which poses low-to-no risk in the design and execution phase. This promotes a learning curve to improve operation & HSE, and ultimately gets positive project economics. Since this simple approach can be implemented early on even during the pre-FEL stage, the FDP team & host authority can come together to jointly discuss the targets/platform ranking and segregate them into various phases. Hence, the number of platforms or drilling centers, and its location also can be optimized early on with this concept, and again, translating into further reduction in overall project cost. This paper will help other operators and host authority to understand better on how a specific development concept on statistical approach can result and turn the matured-challenging fields into more economically attractive projects – low overall development cost and maximizing the recovery.

Battery Management for Small Hydroponic Systems and Cultivation Experiments

2021 ◽  
Vol 11 (3) ◽  
pp. 21-36
Author(s):  
Satoru Yamaguchi ◽  
Takuya Motosugi ◽  
Yoshihiko Takahashi
Keyword(s):  
Open Circuit Voltage ◽  
Low Cost ◽  
Open Circuit ◽  
State Of Charge ◽  
Battery Management ◽  
Charge Capacity ◽  
Hydroponic System ◽  
Soc Estimation ◽  
Hydroponic Systems ◽  
Electronic Load

A small hydroponic system that can use sustainable energy such as solar power has been developed. However, the amount of power generated is not constant, and in the case of unstable weather, enough power cannot be obtained. Therefore, it is necessary to store the generated energy in a battery. In order to design low-cost charging equipment, it is necessary to use a smaller battery and to estimate the remaining charge capacity (state of charge: SOC) accurately. To provide an accurate SOC estimation for such systems, a fusion of CI (current integral) and OCV (open circuit voltage) methods is proposed. When using this method, it is necessary to frequently disconnect the electronic load. In these experiments, the optimum disconnection duration, the effects on plants of frequent battery disconnection, and cutting off of the lighting were investigated.

scholarly journals Aerial physical interaction via IDA-PBC

2019 ◽  
Vol 38 (4) ◽  
pp. 403-421 ◽  
Author(s):  
Burak Yüksel ◽  
Cristian Secchi ◽  
Heinrich H. Bülthoff ◽  
Antonio Franchi
Keyword(s):  
Unmanned Aerial Vehicle ◽  
Control Method ◽  
Low Cost ◽  
Surface Inspection ◽  
Physical Interaction ◽  
External Disturbances ◽  
Aerial Vehicle ◽  
Passivity Based Control ◽  
The Stability ◽  
First Time

This paper proposes the use of a novel control method based on interconnection and damping assignment–passivity-based control (IDA-PBC) in order to address the aerial physical interaction (APhI) problem for a quadrotor unmanned aerial vehicle (UAV). The apparent physical properties of the quadrotor are reshaped in order to achieve better APhI performances, while ensuring the stability of the interaction through passivity preservation. The robustness of the IDA-PBC method with respect to sensor noise is also analyzed. The direct measurement of the external wrench, needed to implement the control method, is compared with the use of a nonlinear Lyapunov-based wrench observer and advantages/disadvantages of both methods are discussed. The validity and practicability of the proposed APhI method is evaluated through experiments, where for the first time in the literature, a lightweight all-in-one low-cost force/torque (F/T) sensor is used onboard of a quadrotor. Two main scenarios are shown: a quadrotor responding to external disturbances while hovering (physical human–quadrotor interaction), and the same quadrotor sliding with a rigid tool along an uneven ceiling surface (inspection/painting-like task).

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