scholarly journals Kinematic Analysis of a Clamp-Type Picking Device for an Automatic Pepper Transplanter

Agriculture ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 627 ◽  
Author(s):  
Md Nafiul Islam ◽  
Md Zafar Iqbal ◽  
Mohammod Ali ◽  
Milon Chowdhury ◽  
Md Shaha Nur Kabir ◽  
...  
Keyword(s):  
Kinematic Analysis ◽  
High Speed ◽  
Model Simulation ◽  
Mechanical Damage ◽  
Maximum Velocity ◽  
Operating Conditions ◽  
High Speed Photography ◽  
Virtual Model ◽  
Significant Difference ◽  
Simulation And Validation

Pepper is one of the most vital agricultural products with high economic value, and pepper production needs to satisfy the growing worldwide population by introducing automatic seedling transplantation techniques. Optimal design and dimensioning of picking device components for an automatic pepper transplanter are crucial for efficient and effective seedling transplantation. Therefore, kinematic analysis, virtual model simulation, and validation testing of a prototype were conducted to propose a best-suited dimension for a clamp-type picking device. The proposed picking device mainly consisted of a manipulator with five grippers and a picking stand. To analyze the influence of design variables through kinematic analysis, 250- to 500-mm length combinations were considered to meet the trajectory requirements and suit the picking workspace. Virtual model simulation and high-speed photography tests were conducted to obtain the kinematic characteristics of the picking device. According to the kinematic analysis, a 350-mm picking stand and a 380-mm manipulator were selected within the range of the considered combinations. The maximum velocity and acceleration of the grippers were recorded as 1.1, 2.2 m/s and 1.3, 23.7 m/s2, along the x- and y-axes, respectively, for 30 to 90 rpm operating conditions. A suitable picking device dimension was identified and validated based on the suitability of the picking device working trajectory, velocity, and acceleration of the grippers, and no significant difference (p ≤ 0.05) occurred between the simulation and validation tests. This study indicated that the picking device under development would increase the pepper seedling picking accuracy and motion safety by reducing the operational time, gripper velocity, acceleration, and mechanical damage.

Forensic Uncertainty Quantification for Experiments on the Explosively Driven Motion of Particles

2018 ◽  
Vol 3 (4) ◽  
Author(s):  
Kyle Hughes ◽  
S. Balachandar ◽  
Nam H. Kim ◽  
Chanyoung Park ◽  
Raphael Haftka ◽  
...  
Keyword(s):  
Uncertainty Quantification ◽  
High Speed ◽  
Early Time ◽  
Operating Conditions ◽  
Quality Data ◽  
High Speed Photography ◽  
Particle Array ◽  
X Ray Imaging ◽  
Drag Models ◽  
Air Force Research Laboratory

Six explosive experiments were performed in October 2014 and February of 2015 at the Munitions Directorate of the Air Force Research Laboratory with the goal of providing validation-quality data for particle drag models in the extreme regime of detonation. Three repeated single particle experiments and three particle array experiments were conducted. The time-varying position of the particles was captured within the explosive products by X-ray imaging. The contact front and shock locations were captured by high-speed photography to provide information on the early time gas behavior. Since these experiments were performed in the past and could not be repeated, we faced an interesting challenge of quantifying and reducing uncertainty through a detailed investigation of the experimental setup and operating conditions. This paper presents the results from these unique experiments, which can serve as benchmark for future modeling, and also our effort to reduce uncertainty, which we dub forensic uncertainty quantification (FUQ).

scholarly journals Simultaneous Pressure Measurement and High-Speed Photography Study of Cavitation in a Dynamically Loaded Journal Bearing

1993 ◽  
Vol 115 (1) ◽  
pp. 88-95 ◽  
Author(s):  
D. C. Sun ◽  
D. E. Brewe ◽  
P. B. Abel
Keyword(s):  
Pressure Measurement ◽  
Cavitation Bubble ◽  
High Speed ◽  
Journal Bearing ◽  
Operating Conditions ◽  
High Speed Photography ◽  
Pressure Data ◽  
Oil Film ◽  
Dynamically Loaded ◽  
Insight Into

Cavitation of the oil film in a dynamically loaded journal bearing was studied using high-speed photography and pressure measurement simultaneously. Comparison of the visual and pressure data provided considerable insight into the occurrence and non-occurrence of cavitation. It was found that (1), cavitation typically occurred in the form of one bubble with the pressure in the cavitation bubble close to the absolute zero; and (2), for cavitation-producing operating conditions, cavitation did not always occur; with the oil film then supporting a tensile stress.

scholarly journals Enhancing Efficiency of Anaerobic Digestion by Optimization of Mixing Regimes Using Helical Ribbon Impeller

Fermentation ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 251
Author(s):  
Buta Singh ◽  
Kornél L. Kovács ◽  
Zoltán Bagi ◽  
József Nyári ◽  
Gábor L. Szepesi ◽  
...  
Keyword(s):  
Model Simulation ◽  
Biogas Production ◽  
Scale Up ◽  
Anaerobic Digester ◽  
Operating Conditions ◽  
Mixing Efficiency ◽  
Dead Zones ◽  
Helical Ribbon ◽  
Significant Difference ◽  
Mixing Intensity

The appropriate mixing system and approach to effective management can provide favorable conditions for the highly sensitive microbial community, which can ensure process stability and efficiency in an anaerobic digester. In this study, the effect of mixing intensity on biogas production in a lab-scale anaerobic digester has been investigated experimentally and via modeling. Considering high mixing efficiency and unique feature of producing axial flow, helical ribbon (HR) impeller is used for mixing the slurry in this experiment under various conditions. Three parallel digesters were analyzed under identical operating conditions for comparative study and high accuracy. Effects of different mixing speeds (10, 30, and 67 rpm for 5 min h−1) on biogas production rate were determined in 5-L lab-scale digesters. The results demonstrated 15–18% higher biogas production at higher mixing speed (67 rpm) as compared to 10 rpm and 30 rpm and the results proved statistically significant (p < 0.05). Biogas production at 10, 30, and 67 rpm were 45.6, 48.6, and 52.5 L, respectively. Higher VFA concentrations (7.67 g L−1) were recorded at lower mixing intensity but there was no significant difference in pH and ammonia at different speeds whereas the better mixing efficiency at higher speeds was also the main reason for increase in biogas production. Furthermore, model simulation calculations revealed the reduction of dead zones and better homogeneous mixing at higher mixing speeds. Reduction of dead zones from 18% at 10 rpm to 2% at 67 rpm was observed, which can be the major factor in significant difference in biogas production rates at various mixing intensities. Optimization of digester and impeller geometry should be a prime focus to scale-up digesters and to optimize mixing in full-scale digesters.

The Influence of Temperature on The Kinetics of Cut Growth in Vulcanizates

1959 ◽  
Vol 32 (3) ◽  
pp. 692-695 ◽  
Author(s):  
V. E. Gul ◽  
S. A. Vilnits
Keyword(s):  
High Speed ◽  
Glassy State ◽  
High Speed Photography ◽  
Influence Of Temperature ◽  
Brittle Solids ◽  
Significant Difference ◽  
Elastomeric Materials ◽  
Influence Of Temperature On ◽  
Published Research ◽  
Kinetics Of

Abstract Recently published research has conclusively demonstrated that rupture in vulcanizates represents a process which increases with time. Slow and fast stages of rupture were discerned. Through the use of high speed photography it was found that, in the usual testing of tensile strength, the rate of rupture growth is initially very small but then quickly although intermittently increases. This behavior occurred both in the rupture of specimens which were not cut and in testing specimens that had been previously cut. The effect of a cut has been thoroughly investigated. Studies conducted on the mechanism of rupture in elastomers indicate that the rupture of vulcanizates has much in common with that of brittle solids. Nevertheless there is a significant difference in the mechanism of rupture in elastomeric materials and brittle solids. It was natural, therefore, to expect a significant change in the kinetics of rupture growth in the region of the glass transition temperature. The aim of the present investigation was to follow the change in the kinetics of rupture of vulcanizates through the transition from the rubbery to the glassy state.

Investigations of Arc Behavior and Particle Formation in the Wire Arc Spray Process Using High Speed Photography

2000 ◽  
Author(s):  
N.A. Hussary ◽  
J. Heberlein
Keyword(s):  
Thermal Spray ◽  
High Speed ◽  
Imaging System ◽  
Metal Droplet ◽  
Droplet Formation ◽  
Operating Conditions ◽  
Arc Spraying ◽  
High Speed Photography ◽  
Spray Process ◽  
The Wire

Abstract The wire arc spraying process, one of several thermal spray processes, gained a sizable part of the thermal spray market, however, more control is needed for this process to be used for high precision coatings. This study is aimed at investigating the liquid metal droplet formation process in order to identify methods for droplet trajectory control. A high speed Kodak imaging system has been used to observe the droplet formation for different operating conditions. Decreasing the upstream pressure and the current levels lead to the reduction in the asymmetric melting of both anode and cathode. By decreasing the interactions of the large eddy structures with the formed metal agglomerates one can achieve better control of the particle trajectories and jet divergence. Thus, coatings can be obtained with higher definition and improved reliability.

A Three-Dimensional Cinematographic Analysis of the Fastball and Curveball Pitches in Baseball

1986 ◽  
Vol 2 (1) ◽  
pp. 20-28 ◽  
Author(s):  
Bruce Elliott ◽  
J. Robert Grove ◽  
Barry Gibson ◽  
B. Thurston
Keyword(s):  
Motion Analysis ◽  
Linear Transformation ◽  
Kinematic Analysis ◽  
High Speed ◽  
Stride Length ◽  
Three Dimensional ◽  
High Speed Photography ◽  
Anatomical Features ◽  
Balance Point

Three-dimensional (3-D) high speed photography was used to record the fastball (FB) and curveball (CB) actions of six members of the Australian National pitching squad. The direct linear transformation (DLT) method of motion analysis for 3-D space reconstruction from 2-D images was used to record the movement of selected anatomical features. Laterally positioned phase-locked cameras operating at 200 fps and a front-on camera operating at 300 fps were used to record the pitching action. Mean pitching velocities for the FB and the CB were recorded. A kinematic analysis of the two pitching motions from the first balance point following the completion of the pump and pivot to follow through are presented. The actions are very similar for the two pitches, as would be expected if disguised to confuse the batter. Minor differences were noted, however, for stride length, forearm action prior to release, and wrist action at release.

Random Behavior of Kerosene Spray Autoignition in Crossflow

2016 ◽  
Author(s):  
Yongsheng Zhao ◽  
Chi Zhang ◽  
Yuzhen Lin
Keyword(s):  
High Speed ◽  
Flow Reactor ◽  
Operating Conditions ◽  
Inlet Temperature ◽  
High Speed Photography ◽  
Primary Analysis ◽  
Photoelectric Detection ◽  
Random Behavior ◽  
Gauss Distribution ◽  
Autoignition Delay

Based on the flow reactor with rectangle cross-section, this paper studies the spray autoignition characteristics of liquid kerosene injected into air crossflow under high temperature and high pressure conditions. Millisecond-level kerosene injection, millisecond-level photoelectric detection, and high speed photography record experiment techniques are adopted in this research. The operating conditions of this research are as follows: 2.3MPa inlet pressure, 917K inlet temperature, fuel/ air momentum ratio of 52, and Weber number of 355. Photoelectric sensor and photomultiplier equipped with CH filter are used to get the autoignition delay time (ADT). A total of 320 experiments are conducted under the same operating conditions in order to obtain the random ADT probability distribution. The high speed photography is utilized to observe and record the developing process of spray autoignition of kerosene. The results show that the ADT varies from 2.5–5.5millisecond (ms) in the above operating conditions, and confirm the existence of the random behavior of kerosene spray autoignition in the crossflow. These random behaviors of ADT can be correlated well with Gauss distribution. The primary analysis shows that the random behavior stems from the random distributions in the diameter and dispersion due to intrinsic turbulence breakup and transportation which dominate the characteristics of spray autoignition.

Dynamics of laser-induced cavitation bubbles near elastic boundaries: influence of the elastic modulus

2001 ◽  
Vol 433 ◽  
pp. 283-314 ◽  
Author(s):  
EMIL-ALEXANDRU BRUJAN ◽  
KESTER NAHEN ◽  
PETER SCHMIDT ◽  
ALFRED VOGEL
Keyword(s):  
Elastic Modulus ◽  
High Speed ◽  
Maximum Velocity ◽  
Biological Tissues ◽  
Bubble Collapse ◽  
Liquid Jet ◽  
High Speed Photography ◽  
Subsequent Formation ◽  
Elastic Boundary ◽  
Bubble Behaviour

The interaction of a laser-induced cavitation bubble with an elastic boundary is investigated experimentally by high-speed photography and acoustic measurements. The elastic material consists of a polyacrylamide (PAA) gel whose elastic properties can be controlled by modifying the water content of the sample. The elastic modulus, E, is varied between 0.017 MPa and 2.03 MPa, and the dimensionless bubble–boundary distance, γ, is for each value of E varied between γ = 0 and γ = 2.2. In this parameter space, jetting behaviour, jet velocity, bubble migration and bubble oscillation time are determined. The jetting behaviour varies between liquid jet formation towards or away from the elastic boundary, and formation of an annular jet which results in bubble splitting and the subsequent formation of two very fast axial liquid jets flowing in opposite directions. The liquid jet directed away from the boundary reaches a maximum velocity between 300 ms−1 and 600 ms−1 (depending on the elastic modulus of the sample) while the peak velocity of the jet directed towards the boundary ranges between 400 ms−1 and 800 ms−1 (velocity values averaged over 1 μs). Penetration of the elastic boundary by the liquid jet is observed for PAA samples with an intermediate elastic modulus between 0.12 and 0.4 MPa. In this same range of elastic moduli and for small γ-values, PAA material is ejected into the surrounding liquid due to the elastic rebound of the sample surface that was deformed during bubble expansion and forms a PAA jet upon rebound. For stiffer boundaries, the bubble behaviour is mainly characterized by the formation of an axial liquid jet and bubble migration directed towards the boundary, as if the bubble were adjacent to a rigid wall. For softer samples, the bubble behaviour becomes similar to that in a liquid with infinite extent. During bubble collapse, however, material is torn off the PAA sample when bubbles are produced close to the boundary. We conclude that liquid jet penetration into the boundary, jet-like ejection of boundary material, and tensile-stress-induced deformations of the boundary during bubble collapse are the major mechanisms responsible for cavitation erosion and for cavitation-enhanced ablation of elastic materials as, for example, biological tissues.

Determination of Void Fraction, Incipient Point of Boiling, and Initial Point of Net Vapor Generation in Sodium-Heated Helically Coiled Steam Generator Tubes

1978 ◽  
Vol 100 (2) ◽  
pp. 268-274 ◽  
Author(s):  
H. C. U¨nal
Keyword(s):  
Heat Flux ◽  
Mass Velocity ◽  
High Speed ◽  
Initial Point ◽  
Operating Conditions ◽  
High Speed Photography ◽  
Centrifugal Forces ◽  
Vapor Generation ◽  
Volumetric Rate ◽  
Rate Ratios

Void fraction was measured with high-speed photography in a 26.7 m and a 40.1 m long, sodium-heated helically coiled steam generator tube of 0.018 m ID. The ratio of coil diameter to tube diameter was 38.9. The operating conditions for the tests were as follows: Pressure: 4–18 MN/m2, mass velocity: 429–1518 kg/m2s, heat flux: 0.013–0.42 MW/m2, outlet subcooling: 0.3–12.5 K, outlet steam quality: 0.000032–0.075. For vapor volumetric rate ratios greater than 0.4, the so-called distribution parameter is not affected by centrifugal forces, and is equal to 0.875. For vapor volumetric rate ratios smaller than 0.4, this parameter is affected by centrifugal forces and the aforesaid ratio. The incipient point of boiling and initial point of net vapor generation were determined with high-speed photography in the aforementioned 26.7 m long helical coil for the following range of operating conditions: Pressure: 4–18 MN/m2, mass velocity 757–1518 kg/m2s, heat flux: 0.082–0.413 MW/m2, outlet subcooling: 4.4–12.5 K. The data were correlated by using both the average and local values of the operating conditions.

Modification of the Reaction Zone Using a Smart Fuel Injector for Control of Instabilities in Liquid Fueled Combustors

2005 ◽  
Author(s):  
T. Conrad ◽  
A. Bibik ◽  
D. Shcherbik ◽  
E. Lubarsky ◽  
B. T. Zinn
Keyword(s):  
High Speed ◽  
Operating Conditions ◽  
High Speed Photography ◽  
Fuel Injector ◽  
Fuel Injectors ◽  
Instability Modes ◽  
Droplet Sizes ◽  
Mass Flow Rates ◽  
The Stability ◽  
Flow Experiments

This paper describes an experimental investigation of suppressing combustion instabilities in a liquid fueled (n-heptane) atmospheric combustor incorporating an array of “smart” fuel injectors. These injectors were designed so that their spray properties could be manipulated without changing the overall operating conditions (power, mass flow rates, equivalence ratio, etc.) of the combustor. The dependence of these spray properties upon the smart injector settings was determined for a single injector using a series of cold flow experiments, including spray images and PDPA measurements of spray velocities and droplet sizes. The stability characteristics of a combustor incorporating seven such injectors were then determined and correlations were drawn between these characteristics, the single injector spray properties, and combustion behavior measurements taken for a single injector. It was shown that both longitudinal and tangential instability modes were excited in this combustor; the mechanisms of excitation and damping of these modes were then further investigated using high speed photography and spectroscopy measurements. Finally, suppression of both modes of instabilities in this combustor were demonstrated by slow tuning of the injector spray properties.

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