Agrotech: Advanced Field Control

Agriculture in most countries is largely dependent on the environmental conditions and climate. Real-time remote monitoring of field conditions allows for early detection of unfavorable conditions developing in the field that is generally a laborious task taken up by the farmers themselves. Additionally, with the rapid shift in climatic conditions and issues pertaining to global warming, the rainfall dependent agricultural yield is promptly affected. In this paper, we present a wireless system using nRF24L01 RF modules to monitor the farm environment conditions and operate the final control element aimed at implementing drip irrigation. The proposed system is designed to be economical and having a capacity for further expansion, allowing the widespread devices across the farm to be controlled. The soil sogginess level is measured by a self-made soil moisture sensor. A ball valve is actuated based on the levels of soil moisture, temperature and humidity checked against a set of predefined levels. The collected data is then pushed onto a cloud platform for future study or use. Keywords: Wireless sensor network, real-time monitoring, nRF24L01 RF module, highly economical and efficient system

Experimental study on an airfoil equipped with an active flow control element

This paper addresses the torque ripple problem of vertical axis wind turbines (VAWT) by applying an oscillating bump which was previously optimised with a numerical model. Since the element primarily affects the drag of an airfoil, a low-speed wind-tunnel experiment using the wake survey method was conducted in order to highlight the effect on the drag of a symmetrical airfoil. Measurements were taken along the centreline of the foil to compare with numerically simulated results on a 2D foil. This study provides an experimental data set for an active flow control device. When the stationary results were compared against numerical simulation they showed an overall good agreement. The moving bump increased the drag coefficient for higher frequencies of oscillation and induced less drag compared to the steady maximum distortion. Uncertainties in the experiments were primarily caused by fluctuations in the test section and the data reduction error. Future work should include the measurement of lift in order to determine the influence of the element on the torque.

Dynamic competition between a ligand and transcription factor NusA governs riboswitch-mediated transcription regulation

Cotranscriptional RNA folding is widely assumed to influence the timely control of gene expression, but our understanding remains limited. In bacteria, the fluoride (F−)-sensing riboswitch is a transcriptional control element essential to defend against toxic F− levels. Using this model riboswitch, we find that its ligand F− and essential bacterial transcription factor NusA compete to bind the cotranscriptionally folding RNA, opposing each other’s modulation of downstream pausing and termination by RNA polymerase. Single-molecule fluorescence assays probing active transcription elongation complexes discover that NusA unexpectedly binds highly reversibly, frequently interrogating the complex for emerging, cotranscriptionally folding RNA duplexes. NusA thus fine-tunes the transcription rate in dependence of the ligand-responsive higher-order structure of the riboswitch. At the high NusA concentrations found intracellularly, this dynamic modulation is expected to lead to adaptive bacterial transcription regulation with fast response times.

Research on Control Strategy of Manipulator Based on Simulation

The force supple control method of robotic arm has been widely researched internationally for many years, and its specific use varies according to the structure of the robotic arm, the location of the sensor, the working space environment, and other factors. Based on the force control principle and control method of the space robot arm, this paper adopts the position-based Cartesian spatial impedance control and proposes an effective forcesmoothing control method after pre-processing the feedback signal of the six-dimensional force sensor installed at the end of the space robot arm with the coordinate system conversion. In addition, the proposed position-based Cartesian spatial impedance control method is modeled and simulated to analyze the effect of each control element on the force-following control effect, to find out the control conditions that can optimize the force-position control effect, and finally to optimize the impedance parameters. This study aims to promote the rapid development of the field of robotic arm control.

SIMULASI PENGARUH BUKAAN VALVE TERHADAP PRESSURE DROP DAN KAVITASI PADA CONTROL VALVE TIPE BALL VALVE DENGAN MENGGUNAKAN SOFTWARE AUTODESK CFD (COMPUTATIONAL DYNAMICS FLUID)

Control valve merupakan suatu instrumen yang digunakan dalam proses industri dan memiliki peran yang sangat penting. Sebagai final control element¸control valve digunakan untuk mengatur aliran fluida agar mampu mengimbangi adanya gangguan serta tetap menjaga variable proses tetap berada pada set point yang diinginkan. Simulasi pengaruh bukaan valve terhadap pressure drop dan kavitasi pada control valve menggunakan autodeks CFD (2019). Kavitasi adalah suatu keadaan yang disebabkan oleh berubahnya fase cairan yang sedang dialirkan dari fase cair menjadi fase uap sehingga menimbulkan gelembung-gelembung. Timbulnya gelembung tersebut disebabkan oleh menurunnya tekanan hingga berada di bawah tekanan uap jenuh cairan tersebut. Adapun variable tetap yang digunakan adalah tekanan 4 atm, 5 atm, 6 atm dan bukaan valve 50 %, 70 %, 90 % dan variable terikat Penurunan tekanan (∆P), Bilangan reynold (NRe), Kavitasi (CN). Di dalam penggambaran geometri valve menggunakan autodeks fusion 360. Untuk bukaan valve yang kecil yaitu 50% penurunan tekanannya sebesar 1.84 atm dengan tekanan awal 5 atm. Bilangan Reynold tertinggi pada bukaan valve 90% dengan bilangan reynold 78,352 dan aliran yang terbentuk adalah turbulen. Indeks kavitasi terendah adalah sebesar 9.47 dan yang tertinggi 36.7. Pada percobaan ini dapat dilihat antara variable terikat, penurunan tekanan dan kavitasi serta variabel bebas bukaan valve dan tekanan yang paling berpengaruh.

ASSESSMENT OF THE LEVEL OF ECONOMIC SECURITY OF INNOVATIVELY ACTIVE ENTERPRISES AS THE BASIS OF THE MANAGEMENT PROCESS WITHIN THE FINANCIAL AND LEGAL FIELD

Today, in the current conditions of enterprise management, it is relevant to build and implement an effective economic security management system in the enterprise’s activities. Accordingly, as a control element, it is necessary to highlight the value of assessing the level of economic security in order to make the company’s specialists successful management decisions. Under the influence of momentary changes in management, it is problematic to select the theoretical and methodological foundations that will be used in such an element of enterprise management, including economic security, as an assessment. Some parameters that are obtained when assessing the level of economic security of an enterprise do not take into account all important aspects of activities. The main goal is to assess the level of economic security of innovatively active enterprises as the basis of the management process within the financial and legal field. The expediency of applying the Solow model to determine the level of economic security of innovatively active enterprises, based on the use of such quantitative indicators as the available labor resources, production assets, the volume of investment in innovation, the volume of non-productive consumption and the final product, is proposed and substantiated. The use of this technique allows us to conclude about the importance of resource provision and the dominant influence of the provision of labor resources to innovatively active enterprises. The research methodology assumes that at the present stage, the assessment of the level of economic security of enterprises is carried out using various methods and techniques. Agreeing with the permanent approaches proposed by economists, we propose to adapt to the system of methods for assessing the economic security of enterprises a method based on the use of the Solow model, the essence of which is that the economic security of an enterprise is considered as a whole economic phenomenon. Keywords: economic security, innovatively active enterprises, management process, financial and legal field JEL Classification B49, C10, C13, M20 Formulas: 5; fig.: 0; tabl.: 1; bibl.: 15.

Ensuring the required law implementation accuracy of the transmission clutches control by regulating the working fluid volume in the hydraulic cylinder compensation chamber

Introduction (problem statement and relevance). Testing the vehicle automatic transmission and shifting gears without interrupting the power flow undesirable dynamic phenomena were revealed. The occurrence of “parasitic” centrifugal pressure in the clutch boosters was observed which resulted in self-activation of the control element, clamping the discs friction linings, which made the hydraulic cylinder emptying and piston removing from the package disks complicated. As a consequence of it there occurred a comfort decrease in the vehicle, and in some cases, the destruction of friction clutches. It was found that the reason for this occurrence was the filling degree instability of the compensation and piston chambers of the hydraulic cylinder clutch, which was not taken into account by the existing calculation and design methods under various initial conditions.The purpose of the study was to improve the implementation accuracy of the required control law of the transmission clutches by purposeful regulating the working fluid volume in the compensation chamber of the hydraulic cylinder clutch.Methodology and research methods. A road test technique was proposed for identifying and reproducing the conditions of the dynamic phenomenon manifestation. The developed mathematical model of the piston stroke made it possible to assess the dependence of the implementation quality of the required clutch control law when individual gears were engaged on the following parameters: the filling degree of the compensation chamber; features of solenoid valves operation; the stiffness of the return spring; the number of clutch friction pairs.Scientific novelty and results. On the experimental research basis of the worked out design and the use of scientifically grounded technical solutions the dynamic effect manifestation of the unbalanced “parasitic” centrifugal pressure rise was excluded.Practical significance. The developed and implemented technical solutions for stabilizing the pressure in the compensation chamber made it possible to ensure the required quality of gear shifting when limiting the dynamic and thermal loading of the friction discs, which made it possible to ensure the required level of dynamic characteristics and comfort ability of the product when shifting gears.

LOSS CHARACTERIZATION OF ADVANCED VIGV CONFIGURATIONS WITH ADJUSTABLE BLADE GEOMETRY

Variable inlet guide vanes (VIGV) are the main control element to adjust the flow rate of industrial centrifugal compressors by customized pre-swirl in the inlet plane of the impeller. The efficient working range of VIGVs is however restricted due to open flow separation occurring at critical stagger angles. In order to overcome the narrow limitations of current blade geometries and to enhance the operating range of the compressor, split blades consisting of a separate front and tail blade segment proved to be particularly promising in previous linear-cascade measurements. Each blade segment is thereby individually staggered. This enables a gradual flow deflection along the chord length. Secondary flow losses, however, were not considered in the previous investigations with linear-cascades. To highlight the potential of the split blade concept under more application-oriented conditions including all relevant flow effects, highly resolved field measurements were conducted in the wake of annular VIGVs. Four different blade configurations, a customary reference case and three variations of the split blade with full, partial and missing sealing in the gap between the segments, were assessed using five-hole probe measurements. By investigating a wide range of stagger angles, the coverage of the full low-loss working range of the VIGV could be ensured. Especially, the fully sealed split blade configuration proved its capacity to extend the efficient operational range significantly.

Optimization of spring barley cultivation technology in the Chernozem region

In the conditions of the Central Chernozem region of Russia, an optimized technology for growing spring barley of the "Vakula" P4 variety was tested. Optimization of the technology was carried out according to the weed control element in five variants, depending on the use of herbicides: Puma Super (farm technology), Ballerina super (optimization), Prima (optimization), Ballerina forte (optimization), Lancelot (optimization). The conducted studies have shown that perennial and annual dicotyledonous weeds have a significant distribution in spring barley crops in the conditions of the Central Chernozem zone. Of these, according to the abundance indicators, white mar, medicinal dymyanka, white sandman, bindweed mountaineer, field yarutka, yellow osot, frankincense pickle predominates. A comparative analysis of optimization on the impact on plant productivity revealed that the most effective technologies for a wide range of weeds were technologies using herbicides Lancelot, Ballerina Super and Ballerina Forte. The highest barley yield of 34.4, 32.3 and 33.7 c/ha, respectively, was noted on these variants of technology application. Key words: SPRING BARLEY, HERBICIDES, CULTIVATION TECHNOLOGY, OPTIMIZATION

Non-contact Crack Detection in Metals Using a Cutoff-Cavity Probe

This paper presents a non-contact method for the detection of surface cracks in metal materials through a forced-resonance microwave method (FRMM) using a cutoff cavity-backed narrow slot as a crack detection probe without using a vector network analyzer (VNA) at microwave frequencies. The FRMM uses the deviations in the ammeter or voltmeter readings of the forcefully obtained resonance of a cutoff-cavity probe for a metal material with or without cracks. The cutoff cavity-backed narrow slot on metal with no cracks produces a series resonance (maximum current) or a parallel resonance through an external control element located on a post inside the cutoff cavity. Cracks were detected by a change in this forced-resonance state (maximum current) when the cutoff-cavity probe was scanned over a crack. The characteristic crack signal was derived from the resonance current deviation on the ammeter located on a post inside the cavity probe. Galerkin’s method of moments was used to obtain a forced-resonance state from which the crack signal of the FRMM was calculated. The experimental measurements for non-contact (remote or lift-off) crack detection are also presented.