Suction Holes Research Articles

Experimental Evaluation of Rootstock Clamping Device for Inclined Inserted Grafting of Melons

A grafting machine is a kind of machine that can quickly graft scion to rootstock instead of manual grafting. Currently, an inclined inserted grafting machine uses the mechanical clamping method, which can easily damage the rootstock seedlings due to its high stiffness, thus, reducing the success rate of grafting. This study proposed an effective, flexible clamping device for grafting. The suction hole diameter (HD), the negative pressure (NP), and the surface inclination angle (IA) of the clamping device were studied via a single factor experiment to obtain optimal parameter ranges. Optimal HD, NP, and IA were 2–3 mm, 4–8 kPa, and 10–20°, respectively. The orthogonal experiment results showed that the optimal parameter combination for maximum holding success rate was HD, 2.5 mm; NP, 6 kPa; and IA, 10°. The experimental verification was carried out using the optimal parameter combination, with a holding success rate of 98.3% and no damage. This study provides a reference for the optimal design of an inclined inserted grafting machine.

Fast-Acting Boundary-Layer Suction Control of Unstarting Flows in an Ethylene-Fueled Dual-Mode Scramjet

The boundary-layer suction control of unstarting flows in an ethylene-fueled dual-mode scramjet was experimentally investigated in the present study. A model scramjet with a rectangular cross-section was tested in Mach 4.5 high-enthalpy freestreams, and an ethylene jet was injected into the model to trigger inlet unstart. Wall-pressure measurements and electronically excited CH (CH*) chemiluminescence imaging were performed to characterize the behavior of the unstarting flows. The overall equivalence ratio in the engine was increased to induce inlet unstart, which was detected based on sudden drops in the pressure, a reduction in power of high-frequency pressure fluctuations, and abnormal CH* emissions in the combustion zone. Two perforated plates with suction holes were installed on the top and one side of the internal surface of the model, and boundary-layer suction control was activated using fast-acting solenoid valves at designated times. Suction from each plate could extract approximately 1% of the freestream flow. Single- and double-plate suction control was also tested under various overall equivalence ratios, with boundary-layer suction found to significantly delay inlet unstart under marginal unstart conditions.

Design Evaluation and Performance Analysis of a Double-Row Pneumatic Precision Metering Device for Brassica chinensis

In view of the low seeding efficiency and precision of seeders used for Brassica chinensis in China, a new double-row pneumatic precision metering device for Brassica chinensis was designed, fabricated, and evaluated. With the characteristics of small size and high sphericity of Brassica chinensis seeds in mind, the structure and key dimensions of the metering plate were determined, and a force analysis of the seed-filling process was carried out. The negative pressure (NP), angular velocity (AV) of the metering plate, and cone angle (CA) of the suction hole were selected as the main influencing factors of the experiment. In order to explore the influence of each single factor and the interaction between factors on the seeding performance, a single factor experiment and a central composite design (CCD) experiment were designed, respectively, and the experimental results were analyzed by analysis of variance (ANOVA). After optimizing the main influencing factors such that the target of the qualified index (QI) was greater than 94% and the miss index (MI) was less than 2.5%, it was found that when CA was 60°, NP was 1.55–1.72 kPa, and AV was 1.1–1.9 rad/s, the seeding performance was excellent. The bench verification results of seeding performance (94% ≤ Q ≤ 100%, 0 ≤ M ≤ 2.5%) and the coefficient of variation (CV) of seed mass (CV of seed mass in outer and inner circle: 5.15%; CV of total seed mass: 8.60%) under the condition of parameter optimization were analyzed; as a result, the accuracy of the parameter optimization was confirmed.

Genetic algorithm for the optimization of vision acquisition for on-the-fly position measurement of individual layers in fuel cell stack assembly

Polymer electrolyte membrane (PEM) fuel cells consist of hundreds of stacked individual layers. As misplacement can lead to product-malfunctions the positioning accuracy plays a crucial role during assembly. Thus, to increase accuracy and to lower the cycle time, this paper presents a camera-integrated gripper for single layer handling of fuel cell components. The overlapping of suction holes within a gripper system is used for position measurement of fuel cell layers. The hole pattern is optimized applying a genetic algorithm to precisely measure the position of individual layers.

Changes in Sensation of Skin Suction Stimulation on Face by Different Shapes of Suction Hole.

Changes in Sensation of Skin Suction Stimulation on Face by Different Shapes of Suction Hole.

Suppression of Bridge Flutter Using Suction Control

To verify the effectiveness of the suction‐based method for improving flutter stability of long‐span bridges, the forced vibration experiments for extracting the flutter derivatives of a section model with and without suction were performed, and the corresponding critical flutter wind speeds of this structure were calculated out. It is shown by the experiment that the flutter stability of the bridge depends on suction configuration. As the suction holes locate at the leeward side of the model, the critical flutter wind speed can attain maximum under the same suction velocity. In the analytical results, it is remarkably effective that the suction control improves the long‐span bridge flutter stability.

Моделювання процесу однозернового дозування вакуумним пневмомеханічним висівним апаратом

The aim of this work is to determine the influence of the surface shape and geometric parameters of the suction hole on the uniformity of seed distribution along the length of the row and determine its rational parameters. The use of mathematical modeling significantly speeds up the research process. An algorithm and a program in the Mathcad system have been developed for simulating the process of separating seeds from the cylindrical, conical and toroidal surfaces of the suction holes of a vacuum pneumomechanical sowing device and their fall to the bottom of the furrow. The algorithm is based on the results of previous studies by the authors. Its initial data is the simulation with the help of a generator of random numbers of spherical seed sizes, which are distributed according to the truncated normal law. Each seed undergoes a process of separation from the surface of the suction hole and free fall to the bottom of the furrow. Computer experiments are repeated, changing the average seed diameters, surface type and geometric parameters of the suction hole surface. As a result of statistical processing of the obtained vector of intervals between adjacent seeds at the bottom of the furrow, the mean sample value of the interval between seeds and the standard deviation of the intervals are determined. The last indicator is chosen by the criterion of uniformity of distribution of seeds on length of a line. Graphs of dependence of this indicator on the investigated parameters are constructed. As a result of the analysis of graphs it was found that the uniformity of seed distribution along the length of the row deteriorates with decreasing average seed diameter and increasing the radius of the suction hole. With a conical surface of the suction hole, the highest uniformity of seed distribution along the row length is achieved at a cone angle γ = 60 ° and a maximum diameter dmaxк=(1,7–2,0) rсем. The highest uniformity of seed distribution along the length of the row can be achieved with a toroidal surface of the suction hole, in particular, with a minimum radius of the radial section of the torus.

Flow field simulation and structural parameter optimisation of vacuum adsorption system for textile fabrics

Vacuum adsorption and grabbing for textile fabrics is one key technology for intelligent garment processing. Owing to the softness and air permeability of textile fabrics, the design of vacuum adsorption grab device has lacked an effective method. In this paper the standard k-epsilon turbulence model is used to analyse the flow field in the suction cavity of vacuum adsorption device for textile fabrics, the optimisation design model of structural parameters is established and solved by the Fluent software, and the verification experiment is carried out. The experimental results show that the suction mechanism with optimised parameters can effectively absorb and grasp the fabric, and the negative pressure required is minimum. The research results show that the structure parameters such as the thickness of the suction cup cavity, the diameter of the suction hole, and the depth of the suction hole affect the adsorption performance of the vacuum adsorption device.

Theoretical Verification of Film Forming in Local Electroplating Process with Electrolyte Suction Tool

Electroplating has many applications, including surface hardening and metal thin film manufacturing. In conventional electroplating, the entire workpiece is immersed in the plating solution. Since the whole surface in contact with the solution is plated, a masking operation to remove the unnecessary plating film is required. This is especially applicable to local plating in the case of ornament plating, surface hardening method, among others. However, these additional processes result in substantial increase in processing time and cost. Earlier, we achieved maskless local electroplating with a smooth surface using a suction tool, in which the electrolyte was retrieved by a suction pump through a suction hole. Even so, formation of film on electroplating is yet to be verified by simulations. Herein, we performed experiments and simulations of the local electroplating by varying the processing time before comparing the results. Finally, the validity of the film forming was examined by discussing the results.

Aerodynamic Investigation on Performance Enhancement of NACA 2412 Airfoil with Suction Assistance

Advanced transport aircraft concept has active boundary-layer control by slot suction which reduces drag by stabilizing the laminar boundary. Thus, the prevention of transition and delaying the boundary layer separation will lead to a higher lift co-efficient. The influence of location and position of suction, suction flow rate and suction hole width on aerodynamic performance have greater influence. These examine the potential payoff for boundary-layer control as applied to the advanced-concept wings. An experimental work deals with the continuous normal suction from the wing upper surface effects on the aerodynamic forces. The wing model with NACA-2412 has been made to achieve normal suction from the wing upper surface by means of four slot channels. The results showed that the continuous normal suction can significantly increase the lift to drag force ratio and this ratio is increasing as the strength of suction increases. There is a convincing decrease in drag and pressure loss and an increase in max lift, which in turn improves the overall performance of the aircraft. While multi-hole suction control can reduce drag much more efficiently than single hole suction control, the position of the suction hole has a greater effect on reducing pressure losses than the suction flow rate.

Suction Controlled Topological Transition in Laminar Juncture Flows

The effect of suction on the topological transition in juncture flow is studied experimentally and numerically. A number of combinations of the positions, where suction is applied, and the flow rates are investigated and their effect on the topological transition of laminar juncture flow is assessed. It is observed that for any particular case, a combination of suction hole positions and volume flow rates can transform the most upstream surface singular point of the horseshoe vortex (HSV) system from a saddle of separation to a saddle of attachment. The topological transition at low suction rates is achieved, when the suction holes are placed close to the separation region. A better HSV control is achieved, when suction is applied close to the juncture at high suction rates. A previously proposed separation/attachment prediction method based on the mass conservation is also confirmed by analyzing the simulated results of suction-controlled and originally-generated wall saddles. The results suggest that the topological transition (separation/attachment) at each wall saddle can be accurately estimated according to the sign of a discriminant coefficient CS/A comprised of the local shear stress τw on the wall and stream-tube width n near the saddle.

Effect of suction control on the aerodynamic characteristics of an elliptical cylinder

To investigate the effect of suction control on the aerodynamic characteristics of an elliptical cylinder immersed in uniform flow, wind tunnel tests of four elliptical cylinder models E1~E4 with different locations of suction holes were carried out under different suction flux coefficient CQ. The Re number based on the equivalent diameter of each model and the oncoming wind speed is about 6.90 ​× ​104. The results show that CQ, the radial angles of suction holes and the placement of main axis of the elliptical model are the main influence factors for the aerodynamic characteristics, which are mainly reflected in terms of the pressure coefficient distributions and aerodynamic force coefficients. There is a threshold value of CQ for the models under suction control, and a significant change of the aerodynamic characteristics occurs when CQ is within it, while the change turns to be unobvious with the further increase of CQ. And the threshold values of CQ are determined to be 0.01, 0.02 and 0.01 for the models E1, E2 and E4 respectively. Among the cases that the major axis of elliptical cylinder is parallel to the oncoming wind direction, the most effective aerodynamic control is acquired by the model E2 whose suction holes are arranged at the leeward side corresponding to the radial angles of 130° and 230°, and the maximum reduction of CD is about 83.7% at CQ ​= ​0.05 when compared to the case without suction control. The aerodynamic characteristics are also significantly improved by suction control for the case that the major axis of elliptical cylinder is perpendicular to the oncoming wind direction, and the maximum reductions of CD, CσD and CσL are about 62.2%, 75.1% and 87.4% respectively.

Desain dan Konstruksi Mesin Penyemai Benih Sayuran Portabel Tipe Vakum untuk Pembibitan pada Talam Semai

In Indonesia, vegetable seeding technique in nursery plug trays still uses manual mechanism. Furthermore, the small size of vegetable seeds makes it difficult to allocate the seeds evenly (1 seed per planting hole). This study aims to design and construct a portable vegetable seeder with a vacuum-type mechanism for nursery needs in plug trays. The methods used in this study were: 1) preliminary test of seed characteristics, 2) functional analysis of the design, 3) structural analysis of the design using CAD, 4) fabricating a prototype, and 5) performance test of the seeder prototype. Seed characteristic used as reference analysis was mustard green seeds. The nursery plug tray used was TS-128L tray (128 planting holes). The results show that the suction requirement of the seeder was 23.119 Pa and the seed suction holes diameter was 1 mm with a cone angle of 120 o . The overall dimensions of the machine are 585 × 430 × 105 mm with 5.26 kg of weight. The suction power uses 220 V AC electric blower with 1.5 A of electric current, 2.5 inches of inlet hole, 3600 rpm of blower rotation and 412.02 Pa of suction power (bigger than the suction requirement of the seeder). The performance test results of seeder using mustard green seeds have been able to achieve the uniformity level of 93.75% (1 seed per planting hole), germination percentage of 95.05% and seeding capacity of 102 trays/hour.

Substantiation of Parameters and Operating Modes for the Bunch Planting Device of the Pneumatic Seeder

Abstract The purpose of this work is to develop a dosing system that provides high-quality bunch planting of watermelon seeds with a given seeding rate and their uniform distribution over the plant nutrition area. It is important to know how many seeds it is needed in the bunch in order to provide the required number of plants in a certain plant nutrition area. The method to achieve this goal is to determine the optimal operating modes for the seeding device, in which the dosing system would supply the seed to the bunch without gaps, searching for dependencies that can determine the required number of the sown seeds in the bunch, taking into account their germination and the number of plants specified by agrotechnical conditions in every bunch. Based on the obtained dependencies, determining the probability of bunches with various numbers of plants, while sowing four seeds in the seedbed with maximum field germination, the design of experimental seed discs is proposed, allowing bunch planting and germination due to easy destruction of the soil crust. At the same time, optimal use of the nutritional area for plants, and, consequently, an increase in the yield of the sown crops is ensured. Experimental seed discs with a group arrangement of suction holes (four cells each) will provide bunch planting of watermelon seeds in accordance with agrotechnical requirements.

Static Torque Characteristic of Cross Flow Fan with Suction Holes and Conductive Flow Plate

Static Torque Characteristic of Cross Flow Fan with Suction Holes and Conductive Flow Plate

Five Year Study of a Unique, Eco-friendly, Menstrual Cup, That Enhances the Quality of Women’s Lives During Menstruation

Menstrual cups are gaining more popularity among women, [1]. who prefer cups over pads and tampons. The innovative FemmyCycle (Figure 2) has several advantages over traditional menstrual cups, which has led to its increased popularity [2]. The objective of this study is to mitigate and correct the possible or potential side effects caused by traditional menstrual cups (Figure 3). The most common side effect among traditional cups is leakage. Despite the fact that 1.9 billion women globally are of menstruating age—spending on average 65 days a year dealing with menstrual blood flow, few good quality studies exist that compare sanitary products, says senior author Penelope Phillips-Howard, a public health epidemiologist from the Liverpool School of Tropical Medicine in the UK. [3]. We focused our study on all causes of leakage and other side effects caused by traditional menstrual cups. Methods of corrective and preventive actions included; the no-spill design, (Figure 4 & Figure 5), use of a removal ring instead of a rigid stem, the use of a flask shaped body rather than the conical shape of traditional menstrual cups, (Figure 2 & Figure 3), the elimination of suction holes and the need to manually open the cup. We analyzed 834 independent reviews by women who have had prior experience with traditional menstrual cups to obtain objective results. The implementation of these design changes and enhancing the written and video instructions produced measurable, objective, positive results in favor of the FemmyCycle. We analyzed all these reviews for FemmyCycle to measure the effects on leakage and other side effects. We selected the reviewers who volunteered to compare the FemmyCycle with their experience with traditional cone shaped menstrual cups. There were many reasons why women preferred FemmyCycle, but the most common by far was the prevention of leakage followed by the ease of insertion, ease of removal and comfort when inserted. The implementation of the design changes from a conical shaped cup with a removal stem to a flask shape cup with a removal ring, in addition to the added no-spill feature and enhanced instructional material, improved the acceptability of the FemmyCycle.

Devising negative pressure within intercuff space reduces microaspiration

BackgroundMicroaspiration past the tracheal tube cuffs causes ventilator-associated pneumonia. The objective of the current study was to evaluate whether creating negative pressure between the tracheal double cuffs could block the fluid passage past the tracheal tube cuffs.MethodsA new negative pressure system was devised between the double cuffs through a suction hole in the intercuff space. Blue-dyed water was instilled above the cuff at negative suction pressures of − 54, − 68, − 82, − 95, − 109, − 122, and − 136 cmH2O, and the volume leaked was measured in an underlying water trap after 10 min. Leakage tests were also performed during positive pressure ventilation, and using higher-viscosity materials. The actual negative pressures delivered at the hole of double cuffs were obtained by placing microcatheter tip between the intercuff space and the artificial trachea.ResultsNo leakage occurred past the double cuff at − 136 cmH2O suction pressure at all tracheal tube cuff pressures. The volume leaked decreased significantly as suction pressure increased. When connected to a mechanical ventilator, no leakage was found at − 54 cmH2suction pressure. Volume of the higher-viscosity materials (dynamic viscosity of 63–108 cP <cP> and 370–430 cP) leaked was small compared to that of normal saline (0.9–1.1 cP). The pressures measured in the intercuff space corresponded to 3.8–5.9% of those applied.ConclusionsA new prototype double cuff with negative pressure in the intercuff space completely prevented water leakage. The negative pressure transmitted to the tracheal inner wall was a small percentage of that applied.

CFD simulation of degas process in medium consistency pump and experiment

The principal of this work is to simulate the degas process and study experimental performance of medium consistency pump. Based on the actual running performance of the MC pulp pumps, the gas-liquid two-phase flow in the pulp pump was numerically simulated, adopting the Eeulerian gas-liquid two-phase flow model and the RNG k-ε turbulence model. The gas-liquid separation and the gas exhausting process were verified based on the gas-liquid distribution inside the turbulence generator and the pump impeller. The impacts of the standpipe liquid level and the vacuum degree of the vacuum pump to the gas discharging effects were studied. The optimal standpipe liquid level, 5.5m, the critical standpipe liquid level, 3.8m, and the critical degree of the vacuum pump, 0.2atm, were defined and obtained from the simulation. Two methods were presented both enhance the gas discharging effect and decrease the flow loss from the suction hole of the MC pulp pump. A sonar flowmeter and monitoring system is used to experimental set up, and the performance characteristics of MC pump in different conditions were studied. The demensionless analysis is applied to pulp pumping. The experimental results show that with vacuum degree increasing pump head increased and gas fraction decreased at pump outlet, and the maximum flow rate increases.

Understanding boundary layer suction and its e ect on wings - A review

Boundary layer suction reduces drag by stabilizing the laminar boundary preventing transition and conceding higher regions of laminar ow. Boundary layer suction(BLS) also postpones boundary layer separation resulting in higher CLmax. This phenomenon is particularly useful in the Aerospace sector and many applications are found and hence understanding the mechanics of BLS becomes critical. Consequently it becomes vital to understand the e ect of BLS during di erent ight regimes and mission pro les. The objective of this review is to understand and document the understanding on BLS and its e ects. The in uence of location and position of suction, suction ow rate and suction hole width on aerodynamic performance by experiments and numerical analysis have been reviewed. It has been brought out that there is a convincing decrease in drag and pressure loss and an increase in max lift which in turn improves the overall performance of the aircraft. While multi-hole suction control can reduce drag much more e ciently than single hole suction control, position of the suction hole has a greater e ect on reducing pressure losses than the suction ow rate. The factors a ecting BLS and its e ects on aerodynamic performance and overall performance of the aircraft has been discussed in this review.

Observation of the spiral flow and vortex induced by a suction pump in superfluid 4He

A suction flow generates a whirlpool, namely a bathtub vortex, in a classical fluid; in contrast, rotating containers, which are usually used for studies of superfluid helium, can produce only simple solid rotation. In the present work, the superfluid flow and concentrated quantized vortices induced by a cryogenic motor immersed in superfluid 4He were investigated. Using a motor with six blades in a cylinder caused the free surface of the superfluid 4He to take on a parabolic shape, indicating that the motor produces a rotating superfluid flow. To drive a suction flow in superfluid helium, the motor was mounted in a cylindrical container with a small hole at the center of the top and a slit at the side, acting as a superfluid pump. This pump was successfully used to generate a spiral flow and a vortex with a funnel-shaped core in superfluid 4He, suggesting that the resulting suction flow transports and centralizes quantized vortices to the suction hole, increasing the vortex circulation and sucking the free surface of the superfluid down.