scholarly journals Operational characteristics of four metering systems for agricultural fertilizers and amendments

2009 ◽  
Vol 29 (4) ◽  
pp. 605-613 ◽  
Author(s):  
Jesus H. Camacho-Tamayo ◽  
Angela M. Barbosa ◽  
Nancy M. Pérez ◽  
Fabio R. Leiva ◽  
Gonzalo A. Rodríguez
Keyword(s):  
Physical And Mechanical Properties ◽  
Crop Productivity ◽  
Operational Parameters ◽  
Commercial Fertilizer ◽  
Rotating Speed ◽  
Feed Screw ◽  
Operational Characteristics ◽  
Speed Range ◽  
Unloading Rate ◽  
Lime Powder

The use of fertilizers and solid amendments in agriculture generates special interest for their effect on crop productivity, as well as for their environmental impact. The efficient use of these products demands knowing their physical and mechanical properties, the storing conditions effect and the operational characteristics of the metering systems used in the fertilizing equipment. In this context, the present study was developed with the purpose of evaluating the operational characteristics of different fertilizing metering systems and to determine the adequate metering system-product operational parameters, using powder lime, powder gypsum, granular 10-30-10 (N-P-K), and granular urea. Operational differences were established among four types of commercial fertilizer metering systems, including wire auger, star-shaped feed wheel, feed screw and ridged traction wheel. The study found that the unloading rate depends directly on the fertilizer metering system's rotating speed and is affected by particle size, repose angle, bulk density and moisture content of the applied product. The wire auger and star-shaped feed wheel metering systems were adequate for the distribution of powder products and the feed screw for granulated fertilizers. Furthermore, theoretical and experimental characteristic equations were established, defining curves for calibration and handling of the products plus the rotating speed range in which a better distributing behavior was achieved.

Investigation of Fan Blades Vibration due to Blade/Casing Rubbing Interactions Using In-Plane Two-Dimensional Model

2018 ◽  
Author(s):  
Jiaguangyi Xiao ◽  
Yong Chen ◽  
Hua Ouyang ◽  
Anjenq Wang
Keyword(s):  
Travelling Waves ◽  
Golden Section ◽  
Contact Forces ◽  
Two Dimensional ◽  
Rotating Speed ◽  
Bladed Disk ◽  
Speed Range ◽  
Blade Vibrations ◽  
Blade Tip ◽  
External Forces

Interactions between casings and bladed-disks of modern turbofan engines may occur through various mechanisms: casing distortions, rotor vibrations and casing vibrations to name a few. These interactions might lead to nonlinear blade vibrations, which could then induce severe damages to both structures. The impacts of casing vibrations on the vibration behaviors of engine blades are studied in this paper. A two-dimensional in-plane model is established in this paper. Fan blade, disk and casing are modeled using beam element. Craig-Bampton model reduction is applied to simplify the model. Penalty method mixed with golden section method is created and used for contact treatments. The interaction is initiated by the external forces acting on the casing. The casing is excited to two-, three- and four-nodal diameter vibration patterns, respectively. In order to capture the core of the problem, contact forces applied to the casing, and casing damping are neglected. Steady casing vibrations could thus be generated. Blade vibrations are calculated in a wide rotating speed range, maximum amplitudes are recorded and studied. The results show that the bladed-disk will have several vibration peaks in the calculated rotating speed range. To figure out the physical mechanisms of these peaks, Fourier spectrums as well as different bladed-disk materials are introduced. Almost all vibration peaks can be explained by three kinds of mechanisms found and summarized in this paper. Two of them are related to travelling waves and the third is related to harmonics. Speed and frequency margins that are related to blade-tip-rub induced vibrations are defined and analyzed. The findings and ideas shown in this paper can be used as a reference in engine preliminary structural design to avoid potential blade tip-rub induced damages.

Experimental Study on a Gyromagnetic Piezo-Cantilever Generator

2013 ◽  
Vol 394 ◽  
pp. 416-420
Author(s):  
Yi Feng Chen ◽  
Jun Wu Kan ◽  
Shu Yun Wang ◽  
Fang Sheng Huang ◽  
Ping Zeng
Keyword(s):  
Experimental Study ◽  
Output Voltage ◽  
Magnetic Force ◽  
Energy Generation ◽  
Peak Voltage ◽  
Research Results ◽  
Rotating Speed ◽  
Speed Range ◽  
Rotating Structure

To meet the demands of the rotating structure for self-power, a novel gyromagnetic piezo-cantilever generator (GPCG) excited by the coupling between rotating magnets and those fixed on piezo-cantilever was presented. The influence of magnetic force (number and configuration of the magnets) and rotating speed on energy generation of the GPCG was investigated experimentally. The research results show that there are 9 optimal rotating speeds for the GPCG to achieve peak voltage at speed range of 0-1390r/min. With 1 magnet (ø12x2mm3) fixed on piezo-cantilever, the increasing number of rotating magnets (ø12x4mm3) in the same place (ns) of the rotator exerts no influence on the optimal rotating speeds, but leads to rising output voltage. At 1042.5r/min, the achieved peak voltages from the GPCG in the case ofns=1/2/4/6 are 13.2/16.6/23.8/27.8V respectively. The optimal speeds decrease and the peak voltage rises with the increasing number of magnets evenly distributed on the rotator (nd). In the case of 1 magnet fixed on piezo-cantilever andnd=1/2/4/8, the optimal rotating speeds and the peek voltages from the GPCG are 708.9/528.2/528.2/264.1r/min and 13.2/16.6/23.8/27.8V respectively.

Motion of AMB Rotor in Backup Bearings

2002 ◽  
Vol 124 (3) ◽  
pp. 460-464 ◽  
Author(s):  
Sheng Zeng
Keyword(s):  
Chaotic Motion ◽  
Nonlinear Response ◽  
Linear Models ◽  
Rotating Speed ◽  
Harmonic Motion ◽  
Power Failure ◽  
Resonance Frequencies ◽  
Speed Range ◽  
Pass Through ◽  
Bearing System

This paper studies numerically the motion of an AMB rotor when it is supported only by backup bearings. Unlike a linear rotor-bearing system, which always undergoes a harmonic motion, the nonlinear AMB rotor-backup bearing system will undergo irregular or chaotic motion at some rotating speeds. The simulations show that in a wide rotating speed range there are several extra resonance frequencies, which are different from those appearing in well-known linear models. When a power failure occurs to AMB machinery, the AMB rotor should pass through all these resonance frequencies. Under some conditions, the full clearance whirl motion of the rotor in backup bearings will happen, which may lead to damage. In this paper several measures that could reduce the nonlinear response and hence avoid the full clearance motion are discussed.

Experimental Study on a Piezoelectric Energy Generator Excited by Rotating Magnets under Different Holding Conditions

2014 ◽  
Vol 620 ◽  
pp. 160-165
Author(s):  
Xian Fang Jin ◽  
Shu Yun Wang ◽  
Jun Wu Kan ◽  
Fang Sheng Huang ◽  
Jie Yu ◽  
...  
Keyword(s):  
Experimental Study ◽  
Monitoring System ◽  
Great Influence ◽  
Magnetic Coupling ◽  
Peak Voltage ◽  
Rotating Speed ◽  
Piezoelectric Energy ◽  
Speed Range ◽  
Coupling Force ◽  
Self Powered

To meet the demand of rotating mechanism for self-powered monitoring system, piezoelectric energy generator (PEG) excited by the magnetic coupling force between rotating magnet fixed on a rotator and one magnet fixed on piezo-beam under different holding condition was presented. The influence of holding conditions (both sides holding, free holding, right side holding and left side holding) and rotating speed on energy generation of the PEG was investigated experimentally. The research results show that the holding condition exerts great influence on the peak voltage and the relative optimal rotating speeds at speed range of 0 to 1200 r/min under one magnet fixed on the end of the piezo-beam and one rotating magnet. Taking a example, when the configuration mode of rotating magnet and the fixed magnet is attract, under free holding the achieved peek voltages from the PEG are 23.6/49.6/69.2V at 300/336/456 r/min respectively. When rotating magnet and the fixed magnet attracting, under left side holding the achieved peek voltages from the PEG are 32.4/33.6/29.2V and under both sides holding the achieved peek voltages from the PEG are 16.4/16.4/16.8V at 300/336/456 r/min respectively.

Compressor Instability Analysis Within a Hybrid System Subject to Cycle Uncertainties

2018 ◽  
Vol 141 (1) ◽  
Author(s):  
Alessandra Cuneo ◽  
Alberto Traverso ◽  
Aristide F. Massardo
Keyword(s):  
Fuel Cell ◽  
Gas Turbine ◽  
Hybrid System ◽  
Stochastic Analysis ◽  
High Speed ◽  
Operating Conditions ◽  
Operational Parameters ◽  
Surge Margin ◽  
Speed Range ◽  
Compressor Surge

The dynamic modeling of energy systems can be used for different purposes, obtaining important information both for the design phase and control system strategies, increasing the confidence during experimental phase. Such analysis in dynamic conditions is generally performed considering fixed values for both geometrical and operational parameters such as volumes, orifices, but also initial temperatures, pressure. However, such characteristics are often subject to uncertainty, either because they are not known accurately or because they may depend on the operating conditions at the beginning of the relevant transient. With focus on a gas turbine fuel cell hybrid system (HS), compressor surge may or may not occur during transients, depending on the aforementioned cycle characteristics; hence, compressor surge events are affected by uncertainty. In this paper, a stochastic analysis was performed taking into account an emergency shut-down (ESD) in a fuel cell gas turbine HS, modeled with TRANSEO, a deterministic tool for the dynamic simulations. The aim of the paper is to identify the main parameters that impact on compressor surge margin. The stochastic analysis was performed through the response sensitivity analysis (RSA) method, a sensitivity-based approximation approach that overcomes the computational burden of sampling methods. The results show that the minimum surge margin occurs in two different ranges of rotational speed: a high-speed range and a low-speed range. The temperature and geometrical characteristics of the pressure vessel, where the fuel cell is installed, are the two main parameters that affect the surge margin during an emergency shut down.

scholarly journals Modeling of compositions and predicting properties of modified mixtures for rough thin-layer coatings

2020 ◽  
Vol 7 (2) ◽  
Author(s):  
Dmitriy Chernykh ◽  
Mihail Pakin
Keyword(s):  
Thin Layer ◽  
Building Materials ◽  
Physical And Mechanical Properties ◽  
Graphical Form ◽  
Operational Parameters ◽  
Mathematical Planning ◽  
Statistical Research ◽  
Second Stage ◽  
Optimal Values ◽  
Planning Of Experiments

In recent years, the approach to experimental and statistical research and optimization of complex multicomponent systems has changed radically. In various fields of scientific and technical research, methods of mathematical planning of experiments are successfully used. Their wide application significantly increases the effectiveness of research, as well as proves their universality and suitability in most studies of building materials. As a result, the authors present a method of mathematical planning of the experiment, which is used to optimize the composition and properties of modified mixtures for rough thin-layer coatings. This method allows a fairly complete and comprehensive assessment of the effect of components on the properties of modified mixtures and to obtain a mathematical model of the process in graphical form, as well as to obtain a theoretical model for evaluating and predicting the physical, mechanical and operational properties of the materials under study. In this article, the first stage of research was used to select the percentage of binder, hydrate lime and additives, and also studied the influence of the variation factor of these components on the physical and mechanical properties of the mixture. At the second stage, changes in response functions were investigated. The results of a complete three-factor experiment allowed us to establish rational ranges of values of the studied components in order to obtain mixtures for rough concolay coatings with optimal values of physical, mechanical and operational parameters.

scholarly journals Fare inequities in public transit system in Costa Rica

2021 ◽  
Vol 31 (2) ◽  
pp. 80-97
Author(s):  
Cristhian Santiago Quirós Calderón ◽  
Jonathan Agüero-Valverde
Keyword(s):  
Costa Rica ◽  
Public Transport ◽  
Public Transportation ◽  
Multilevel Modelling ◽  
Random Coefficients ◽  
Operational Parameters ◽  
Transit System ◽  
Operational Characteristics ◽  
Operational Variables ◽  
In Transit

Problems in transit fare equity affect the daily commute of specific groups that depend mostly on public transportation. Previous studies showed that some routes present operational characteristics that increased the price charged to the users. To address this issue, a methodology to identify the routes that have fares much higher than expected, after considering operational parameters, is developed. This paper presents a methodology implemented to evaluate fare inequities in public transport networks. The case study is the bus public transport network in Costa Rica. The evaluation is performed using fare per kilometer as independent variable and operational variables, such as route length, monthly ridership and vehicle occupancy by using cluster analysis and Bayesian multilevel modelling. The results indicate that random coefficients models perform better than independent models for clustered data. Furthermore, the routes with higher differences between observed and estimated (i.e. expected) fares are the ones to be addressed first in individual audits, because these are the routes who charge higher operational costs into the fare, increasing inequity among the population.

Analysis of operation of new construction of the frictional joint with the resistance wedge / Analiza pracy nowej konstrukcji złącza ciernego z klinem oporowym

2012 ◽  
Vol 57 (1) ◽  
pp. 209-227 ◽  
Author(s):  
Jarosław Brodny
Keyword(s):  
Simulation Analysis ◽  
Steel Frames ◽  
Loading Capacity ◽  
Operational Parameters ◽  
Basic Part ◽  
Axial Forces ◽  
Operational Characteristics ◽  
New Construction ◽  
Frictional Joints ◽  
Physical And Mathematical Models

Frictional joint is the basic part of the friction props and yielding steel frames of dog headings. It constitutes a constructional connection and have decisive influence on the basic operational parameters of the steel frames and props, i.e. their loading capacity and yielding capacity. Currently applied constructions of frictional joints characterize with low loading capacity and unstable operation. In order to improve their operational parameters a new constructional solution of frictional joint, consisting on the application of resistance wedge assembled between the cooperating sections, was developed. Application of the resistance wedge caused an increase of resistances to motion in the frictional joint, what influenced on the increase of its loading capacity and on the increase of values of axial forces in the bolts of stirrups. In the paper results of stand tests of frictional joints with the resistance wedge, subjected to the static axial compression and impact of freely falling mass, were presented. In order to determine the influence of the resistance wedge on the operational parameters of the frictional joint, obtained results were compared with the results of studies of the frictional joints without the resistance wedge. On the basis of stand tests a physical and mathematical models of the frictional joint with the resistance wedge, were developed, and utilized to simulation analysis of its operation at impulse loading. On the basis of conducted tests and analysis one can state, that application of the resistance wedge influences on the enhancement of loading capacity, improves the state of loading the bolts in stirrups, and creates possibility of regulation of operational characteristics of the frictional joints

scholarly journals Optimization of Ingredients upon Development of the Protective Polymeric Composite Coatings for the River and Sea Transport

2021 ◽  
Vol 23 (2) ◽  
pp. B89-B96
Author(s):  
Andriy Buketov ◽  
Serhii Yakushchenko ◽  
Abdellah Menou ◽  
Oleh Bezbakh ◽  
Roman Vrublevskyi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Epoxy Composite ◽  
Composite Coatings ◽  
Physical And Mechanical Properties ◽  
Polymeric Composite ◽  
Epoxy Oligomer ◽  
Mathematical Planning ◽  
Sea Transport ◽  
Operational Characteristics ◽  
Critical Content

It is proved that in order to increase the operational characteristics of parts of the river and sea transport, including their physical and mechanical properties, it is advisable to use the protective polymeric composite coatings. The effect of fillers on the flexural stresses of the developed epoxy composite was analyzed. The critical content of components was determined by the method of mathematical planning of the experiment: the synthesized powder mixture - 0.05 pts.wt., discrete fibers - 0.10 to 0.15 pts.wt. per 100 pts.wt. of epoxy oligomer ED-20. Introduction of such ingredients into the epoxy binder allows to increase the flexural stresses to σ f=77.4…78.6 MPa. The obtained results allow to create materials with improved values of physical and mechanical properties.

scholarly journals Numerical Simulation of Solid-Fluid 2-Phase-Flow of Cutting System for Cutter Suction Dredgers

2018 ◽  
Vol 25 (s2) ◽  
pp. 117-124 ◽  
Author(s):  
Min Zhang ◽  
Shidong Fan ◽  
Hanhua Zhua ◽  
Sen Han
Keyword(s):  
Flow Characteristics ◽  
Continuous Phase ◽  
Parameters Optimization ◽  
Phase Flow ◽  
Operational Parameters ◽  
Two Phase ◽  
Rotating Speed ◽  
Discrete Phase ◽  
Different Characteristics ◽  
Cutting System

Abstract The study of the flow characteristics of the solid-fluid two phase flow in the cutter suction dredger is very important for exploring the slurry formation mechanism and optimizing the operational parameters. In this study, standard k-ε model and Multiple Reference Frame are applied to numerically simulate flow field in and around the cutting system, then with the steady convergent result of the simulation as the initial condition, Discrete Phase Mode is used to solve the particle motion equation by fully coupling the continuous phase and the particles. The influence of suction flow velocity and cutter’s rotating speed on particles suction are analyzed, and effectively suctioned particles numbers are also quantitatively studied. The simulation result shows that the DPM model is able to simulate the movement of particles in and around the cutter suction dredger’s cutting system, in the fluid flow filed velocity vector and pressure distribution on different planes show different characteristics, and under higher suction velocity and lower cutter rotating speed more particles are suctioned into the suction inlet. The results can help better understand flow characteristics of solid-fluid 2-phase-flow of cutter suction dredger’s cutting system, and provide theoretical support for relative system design and operational parameters optimization.

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