Blade Size Research Articles

Savonius wind turbine blade selection based on computational fluid dynamics

The Savonius vertical axis wind turbine is widely used because of its simple design and efficiency at low wind speeds. The next development is the mini multi-blade Savonius helical wind turbine. At this miniature size, the performance of a mini multi-blade helical Savonius turbine due to variations in the number of blades and its impact on the energy produced has not been investigated in depth. Therefore, adjustments to the size and number of blades need to be made to optimize the performance of this turbine. The research aims to obtain the performance of the Savonius type S wind turbine with 3 blades and 4 blades using the CFD (Computational Fluid Dynamics) method. The main dimensions of the simulation model are the shaft diameter of 0.008 m, the outer diameter of 0.24 m, the height of 0.4 m, and the number of blades 3 and 4. The inner diameter of the 3-blade turbine is 0.21 m while the inner diameter of the 4-blade turbine is also 0.21 m. Both turbine models are subjected to wind speeds of 4 m/s, 5 m/s, and 6 m/s. Based on the simulation results, a turbine with 4 blades has more optimal performance compared to the 3-blade type. At a wind speed of 6 m/s, the 4-blade Savonius helical turbine produces a rotation of 498,215 rpm and a maximum power of 6,129 watts. Meanwhile, the Savonius turbine with 3 blades at a wind speed of 6 m/s produces a rotation of 545,655 rpm and a maximum power of 4,390 watts. This difference in performance shows the importance of adjusting the number of blades in wind turbine design to achieve optimal efficiency. This research provides useful insights for the further development of mini helical Savonius wind turbines in various wind conditions

Drepananthus khaosoi sp. nov. (Annonaceae) from southern Thailand, with molecular phylogenetic reconstructions

Drepananthus khaosoi sp. nov., a new species from southern Thailand is described and illustrated. It is morphologically most similar to D. ridleyi, especially in the very narrow and elongated petals, but differs in leaf blade size, leaf base, monocarp shape and appearance, monocarp width, length of monocarp stipe, pericarp thickness and seed arrangement. Molecular phylogenetic analyses using chloroplast DNA regions (matK and rbcL exons; trnL intron; atpB-rbcL, psbA-trnH and trnL-trnF intergenic spacers) and including 18 Drepananthus species confirm the monophyly of Drepananthus, but the relationships within the genus are largely unresolved, including a failure to elucidate a sister group of D. khaosoi. The conservation status of the new species is provisionally assessed as Critically Endangered.

Design and analysis of hundred-meter wind turbine blade trailing edge based on finite element method (FEM)

Abstract The trailing edge region of composite wind turbine blades usually has a large deformation under wind load and the accidents caused by the damage of blade trailing edge accounts for a large proportion among blade accidents. With the development of large blade size, higher requirements are put forward for the stability of wind turbine blade trailing edge. Therefore, the trailing edge region is critical in the design of blade. A detailed study of the design and analysis for wind turbine blade trailing edge region was carried out in which the structure stability was regarded as the key. The influence of auxiliary spar cap and auxiliary spar web on the stiffness distribution and stability of the trailing edge were studied based on focus and finite element method (FEM). The respiratory effect of different structures due to deformation were analyzed and compared. The results showed that the structure of the auxiliary spar cap and auxiliary spar web can significantly increase stiffness, stability and decrease respiratory deformation at the trailing edge of blade compared to the traditional three webs structure. The structure of auxiliary spar and auxiliary spar web is the best design scheme for hundred-meter composite blade trailing edge.

Inhomogeneous fan-shaped surface state induced by isolated Weyl points in acoustic crystals and the associated multi-frequency sound-wave filters

The nontrivial surface states excited by isolated Weyl points (IWPs) have been scarcely studied to date, primarily due to their circumvention from the Nielsen-Ninomiya no-go theorem. In a groundbreaking study on this topic [Adv. Sci., 10, 2207508 (2023)], we discovered that IWPs can generate a novel nontrivial surface state, namely the multi-fold fan-shaped surface state, which we named. Here, we report another type of fan-shaped surface state generated by an IWP surrounded by a closed Weyl nodal wall (WNW). Unlike previous findings, the fan-shaped surface state discovered here exhibits inhomogeneous in spatial distribution, with significantly varying sizes of the fan blades. Moreover, this surface state can be generated by a charge-four IWP protected by the rotation symmetries {C31+|000}, {C2z|12012}, {C2x|01212} and the time-reversal symmetry in the space group (SG) No. 198. Importantly, our simulation results of the acoustic crystals in this SG revel that the inhomogeneous fan-shaped surface state can provide multiple channels for acoustic wave transmission without energy dissipation, demonstrating that this kind of nontrivial surface state offers an effective mechanism for designing multi-frequency acoustic wave filters and selectors.

Multifoliate alfalfa: its causes and influence

An increase in the leafiness of protein-rich alfalfa (Medicago) is possible not only through selection to change the size of the leaf blade. Some of the first reports on the study of the phenomenon of the formation of additional leaves, afterwards called multifoliate, date back to the 30 years of the XX century. This review article mentions the main articles related to the study of the trait. The structure of the leaf is described and information is collected on the correlations of multifoliate with height, internodes, day length and temperature. The influence of germplasm and research methods on obtaining contradictory data is indicated. The assumptions initially put forward by researchers about the atavistic nature of the manifestation of the trait, and later about the presence of a recessive mutation with 2 additive genes regulating expression, are considered. The method of finding the index of evaluation of the expression of multifoliate proposed by Craig Sheaffer and confirming the strong character of inheritance of the trait in classical selection through recurrent selection is shown. In conclusion, the most significant genes and gene families that directly or indirectly affect the manifestation of multifoliate, including PALM1 and KNOX, are collected.

Study on coupled mode flutter parameters of large wind turbine blades

As the size of wind turbine blades increases, the flexibility of the blades increases. In actual operation, airflow flow can cause aerodynamic elastic instability of the blade structure. Long blades may experience coupled mode flutter due to the bending torsion coupling effect, leading to blade failure. Based on Euler Bernoulli beam theory combined with Theodorsen non directional aerodynamic loads, a blade flutter characteristic equation is established through finite element method. Taking NREL 5 MW wind turbine blades as an example, analyze the influence of parameter changes in different regions of the blades on flutter characteristics. Research has found that paramter changes in the tip region of blade have the greatest impact on flutter characteristics. The vibration frequency shows an overall upward trend with the increase of waving stiffness and torsional stiffness. The flutter velocity of the three regions tends to stabilize as the bending stiffness decreases. The blade flutter speed increases with the increase of torsional stiffness. The radius of gyration is inversely proportional to the flutter frequency and flutter velocity. The impact of centroid offset on blade structure flutter frequency is minimal, but the centroid offset in the tip region has a greater impact on flutter velocity. Increasing the torsional frequency can prevent coupled mode flutter and provide a theoretical basis for blade flutter prevention design.

Assessing the impact of vortex generators on the dynamic stall behaviour of a thick airfoil

Modern slender wind turbine blades use thick inboard airfoils and thicker trailing edges prone to flow separation. The increasing size of these flexible blades amplifies the importance of considering unsteady aerodynamics during the design phase. Environmental conditions result in Leading Edge Erosion (LER), further complicating the sectional unsteady aerodynamic behaviour. Although vortex generators are a well-studied method for passive separation control under steady conditions, their influence on unsteady aerodynamics for clean and rough blade sections is an area that requires further exploration. While some numerical studies exist, reliable experimental data is lacking in the literature. This work presents experimental results on the dynamic stall behaviour of a DU97W300 airfoil, a typical thick root section. The investigation covers both clean and rough conditions, both with and without VGs, to create an understanding of how VGs impact dynamic stall. Moreover, various VG array configurations are used to study the parametric dependence of dynamic stall phenomena on the VG array parameters.

Individual architecture and photosynthetic performance of the submerged form of Drosera intermedia Hayne

Drosera intermedia grows in acidic bogs in parts of valleys that are flooded in winter, and that often dry out in summer. It is also described as the sundew of the most heavily hydrated habitats in peatlands, and it is often found in water and even underwater. This sundew is the only one that can tolerate long periods of submersion, and more importantly produces a typical submerged form that can live in such conditions for many years. Submerged habitats are occupied by D. intermedia relatively frequently. The aim of the study was to determine the environmental conditions and architecture of individuals in the submerged form of D. intermedia. The features of the morphological and anatomical structure and chlorophyll a fluorescence of this form that were measured were compared with analogous ones in individuals that occurred in emerged and peatland habitats. The submerged form occurred to a depth of 20 cm. Compared to the other forms, its habitat had the highest pH (4.71–4.92; Me = 4.71), the highest temperature and substrate hydration, and above all, the lowest photosynthetically active radiation (PAR; 20.4–59.4%). This form differed from the other forms in almost all of the features of the plant’s architecture. It is particularly noteworthy that it had the largest main axis height among all of the forms, which exceeded 18 cm. The number of living leaves in a rosette was notable (18.1 ± 8.1), while the number of dead leaves was very low (6.9 ± 3.8). The most significant differences were in the shape of its submerged leaves, in which the length of the leaf blade was the lowest of all of the forms (0.493 ± 0.15 mm; p < 0.001) and usually the widest. The stem cross-sectional area was noticeably smaller in the submerged form than in the other forms, the xylem was less developed and collaterally closed vascular bundles occurred. Our analysis of the parameters of chlorophyll fluorescence in vivo revealed that the maximum quantum yield of the primary photochemistry of photosystem II is the highest for the submerged form (Me = 0.681), the same as the maximum quantum yield of the electron transport (Me φE0 = 0.183). The efficiency of energy use per one active reaction center of photosystem II (RC) was the lowest in the submerged form (Me = 2.978), same as the fraction of energy trapped by one active RC (Me = 1.976) and the non-photochemical energy dissipation (DI0/RC; Me = 0.916). The ET0/RC parameter, associated with the efficiency of the energy utilization for electron transport by one RC, in the submerged plant reached the highest value (Me = 0.489). The submerged form of D. intermedia clearly differed from the emerged and peatland forms in its plant architecture. The submerged plants had a thinner leaf blade and less developed xylem than the other forms, however, their stems were much longer. The relatively high photosynthetic efficiency of the submerged forms suggests that most of the trapped energy is utilized to drive photosynthesis with a minimum energy loss, which may be a mechanism to compensate for the relatively small size of the leaf blade.

The ophthalmologic crescent blade in endonasal surgery.

The angled tip and small size of the crescent blade provide versatility for its use in a variety of endonasal procedures. The crescent blade enables cutting along 180° from the tip, ensuring a tangential cut through the mucosa, which is important for flap viability. The disposable nature of the blade ensures that it is always sharp, allowing for its use in mucosal and cartilaginous cuts.

Morphological and Molecular Characters Differentiate Common Morphotypes of Atlantic Holopelagic Sargassum

Since 2011, massive new strandings of holopelagic Sargassum have been reported on the coasts of the Caribbean, northern Brazil, Guiana, and West Africa, causing severe economic and ecological damage. Three common morphotypes (S. fluitans III, S. natans I, and S. natans VIII) were identified as responsible for these catastrophic events, with dominance shifts between them over time. However, the taxonomic status of these holopelagic Sargassum morphotypes remains unclear. Using an integrative taxonomy framework, combining a morphological study and molecular analyses, this study aimed to clarify their taxonomic status. Morphological analyses of 54 characters revealed no intermediate form between the three morphotypes, with the overall shape, nature of the axis, and size and shape of blades and vesicles being the most discriminating. An analysis of mitochondrial (IGS, cox2, cox3, mt16S rRNA, and nad6) and plastid (rbcL) markers confirmed the genetic divergence among the three morphotypes, with a lower level of divergence between the two S. natans morphotypes. Without additional molecular characterization, these morphotypes cannot be classified as three distinct species. However, due to their distinct morphological characteristics and sympatry within drifting aggregations, a revision of holopelagic species names is proposed, with Sargassum fluitans var. fluitans (for S. fluitans III), Sargassum natans var. natans (for S. natans I), and S. natans var. wingei (for S. natans VIII). This revision provides necessary clarity on the species involved in inundations of the tropical Atlantic.

Numerical analysis of aero-hydrodynamic wake flows of a floating offshore wind turbine subjected to atmospheric turbulence inflows

The influence of atmospheric turbulence inflow on coupled dynamic behaviors and wakes of floating offshore wind turbine (FOWT) is pronounced, especially as blade size increases. In this study, we explore the effects of atmospheric inflow on aero-hydrodynamics and wake characteristics of a spar-type FOWT. A well-validated in-house computational fluid dynamic (CFD) solver, FOWT-UALM-SJTU, is utilized to conduct the numerical simulations. To generate the realistic atmospheric inflow condition, the large eddy simulation (LES) with long-duration is employed. Two other cases involving uniform inflow and shear inflow are conducted to provide some comparable results. Compared to uniform inflow and shear inflow, the power and thrust of FOWT under atmospheric inflow display greater instability, with their power spectrums exhibiting higher intensity in high frequency region. The variation of yaw moment in atmospheric scenario is significantly drastic, leading to a remarkable response in platform yaw motion. Notably, the dominant frequency in this scenario is the blade passage frequency, as opposed to the incident wave frequency observed in the uniform and shear scenarios. The atmospheric inflow promotes the manifestation of wake breakdown and wake meandering, resulting in the faster wake recovery of FOWT. Besides, the meandering in the far wake is more significant compared to uniform and shear scenarios. The absence of vortex rings in atmospheric scenario is observed, along with the presence of more complex and smaller vortices in far wake. Our findings highlight the remarkable impacts of atmospheric inflow on dynamic responses and wake evolution of FOWT, and it is recommended that the atmospheric inflow be taken into account when assessing wake interactions between multiple FOWTs.

Analysis of the variability of morphometric and physiological parameters of grain crops when using biofertilizers

Currently, solving the problem of improving agricultural crops’ productivity is of great relevance. The parameters of photosynthetic activity play an important role in photosynthesis and ensure the efficient functioning of plants under various conditions. Understanding of these processes helps better understand the mechanisms of plant growth and development, as well as develop methods to increase productivity and resistance to stress conditions. The purpose of the current study was to estimate the effect of biofertilizers on the functioning of the photosynthetic apparatus and the variability of the area of leaf blades of agricultural grain crops (durum wheat, spring barley), and to establish the dependence of productivity on the ameliorant used. The objects of study were the spring barley variety ‘Anna’ and the durum wheat variety ‘Orenburgskaya’. The area of the leaf blade was measured by scanning using the APFill Ink&amp;Toner Coverage Meter program. To determine the chlorophyll content, there was used a portable N-tester. There has been reliably established positive correlation between productivity increase and the size of the leaf blade of the experimental plants. The application of the studied biofertilizer has had a positive effect on chlorophyll increase in the barley leaf blades. This explains the possibility of changing the studied parameters by agricultural methods (fertilizer application). There has been found a significant correlation (at p˂0.05) between the height parameters with a number of seeds in a head (r = 0.63) and a leaf blade area (r = 0,69), a number of seeds in a head and productivity (r = 0.86). As a result of the study, there has been established a relationship between some quantitative parameters of the seed material (head length – number of seeds in a head), and a positive correlation was identified between a leaf area and a head length (r = 0.69). There has been obtained a significant dependence of barley productivity on the ameliorant used. At the same time, the productivity increase when using fertilizer compared to the control was 58.9 %.

Pre-selection blade size choice for the microsurgical clipping of cerebral artery aneurysms: A numerical study

BackgroundBrain strokes comprise the third leading cause of death worldwide. Microsurgical clipping is recognized as being one of the most effective approaches to the treatment of brain aneurysms. The incomplete closure of the distal-side aneurysm neck is the most common cause of the persistent filling of the dome. Since the diameter of the neck increases when the neck of the aneurysm is squeezed closed by the blades of the clip, the blades should be correspondingly longer. This study provided an assessment of whether the presurgical selection of clips using a 3D planning system is feasible in terms of selecting the most suitable clip for aneurysm occlusion. MethodsThe computational model was created based on computer tomography data obtained from nine brain aneurysms. The closing of the aneurysm was provided in two steps. The first the length of the blades used for closing corresponded to the length of the aneurysm neck as confirmed by the radiological measurements. The second the length of the blades was adjusted according to stage one, so as to determine the minimum required for the closure of all the gaps in the interior space of the aneurysm neck. ResultsNo differences were detected between the radiological measurement of the aneurysm neck size and the measurements obtained from the reconstructed stereolithographic 3D models. It was observed that the size of the aneurysm neck increased following clipping by 40% to 60% of its original size. The larger the aneurysm neck, the greater the deformation of the aneurysm. ConclusionFirstly, the 3D reconstruction of CT/MRI data did not result in any loss of accuracy and the measurement of the neck of the aneurysm was the same for both of the methods employed. The second, and more important, outcome was that the deformation of the neck of the cerebral aneurysm is at least 1.4x greater than its original size. This information is essential in terms of the pre-selection of the size of the clip.

Performance and Damage Study of Composite Rotor Blades under Impact.

A military helicopter is easily attacked by bullets in a battlefield environment. The composite blade is the main lifting surface and control surface of the helicopter. Its ballistic performance directly determines the vulnerability and survivability of the helicopter in the battlefield environment. To study the ballistic performance of the composite helicopter blade, the damage characteristics of the impacted composite rotor blade are obtained by experiments. A numerical simulation model is established by applying Abaqus software to predict the blade ballistic damage. The three-dimensional progressive damage failure model is used to analyze the ballistic damage under the experimental conditions. The effectiveness and accuracy of the numerical simulation model are verified through a comparison with the experimental results. The ballistic damage of composite blades under three experimental conditions was investigated. The results show that the ballistic damage type of composite blade mainly includes delamination, fiber breakage, and foam collapse. The damage to the composite material at the position of bullet incidence is mainly local shear fracture, while the damage to the composite material at the exit position is mainly fiber tensile fracture. The ballistic damage size of the composite blade is closely related to the ballistic position, incident angle, and structure characteristics along the ballistic path. The larger the incident angle, the smaller the ballistic damage size of the blade. The greater the structural stiffness of the structure near the exit, the greater the damage size of the exit. The numerical simulation model presented in this paper can provide a reference for research on the ballistic performance of composite helicopter blades.

Influence of Curved Video Laryngoscope Blade Sizes and Patient Heights on Video Laryngoscopic Views: A Randomized Controlled Trial.

This study aimed to compare the video laryngoscope views facilitated by curved blades 3 and 4 with an exploration of the relationship between these views and patient height. Conducted as a randomized controlled trial, this study enrolled adults scheduled for surgery under general anesthesia. Intubation procedures were recorded, and the percentage of glottic opening was measured before tube insertion. Multivariate analysis validated the impact of various factors, including blade size and patient height, on the percentage of glottic opening scores. A total of 192 patients were included. The median percentage of glottic opening scores for curved blades 3 and 4 were 100 and 83, respectively (p < 0.001). The unstandardized coefficient indicated a significant negative impact of blade 4 on the percentage of glottic opening scores (-13, p < 0.001). In the locally estimated scatterplot smoothing analysis, blade 3 exhibited a steady rise in glottic opening scores with increasing height, whereas blade 4 showed a peak followed by a decline around 185 cm. The unstandardized coefficient of height showed no significant association (0, p = 0.819). The study observed superior laryngoscopic views with blade 3 compared to blade 4. However, no significant association was found between laryngoscopic views and patient height.

Numerical and experimental investigations on a bladeless turbine: Tesla's cohesion-type innovation

The design, numerical simulation, manufacturing, and physical experimentation of Tesla's bladeless centripetal turbine for electrical power production are the topics of this research project. The turbine generates rotational motion in the discs by directing pressurized air and water tangentially across parallel smooth disc surfaces. The fluid speed parameter at the nozzle inlet determines the power generated. To ensure optimal mechanical design parameters, SolidWorks design software, fluid dynamics concepts, and machine element design were employed. The numerical simulation software ANSYS CFX was used. The numerical and qualitative findings of the models and physical experiments coincided well. The study revealed that the power production and turbine efficiency were regulated by the input sources and blade size. Variations in the fluid composition between the discs may additionally have an impact on the outcomes. The researchers investigated the connection between input fluid pressure and turbine efficiency, as well as the number of discs and turbine power. The prototype could generate 76.52 W of electricity at 50 bar pressure and 1.01e+05 Reynolds number. The operation was efficiently simulated using CFD, with only a 9.3% difference between experimental and simulated results. Overall, this research provides an in-depth assessment of Tesla's bladeless centripetal turbine. It verifies the design and numerical simulation methodologies used, as well as identifies the essential aspects impacting turbine performance and efficiency. The findings contribute to a better understanding of the turbine's behavior and give ideas for improving its performance.

The utilization of video laryngoscopy in nasotracheal intubation for oral and maxillofacial surgical procedures: a narrative review.

The video laryngoscope is a novel instrument for intubation that enables indirect visualization of the upper airway. It is recognized for its ability to enhance Cormack-Lehane grades in the management of difficult airways. Notably, video laryngoscopy is associated with equal or higher rates of intubation success within a shorter time frame than direct laryngoscopy. Video laryngoscopy facilitates faster and easier visualization of the glottis and reduces the need for Magill forceps, thereby shortening the intubation time. Despite the advanced glottic visualization afforded by video laryngoscopy, nasotracheal tube insertion and advancement occasionally fail. This is particularly evident during nasotracheal intubation, where oropharyngeal blood or secretions may obstruct the visual field on the monitor, thereby complicating video laryngoscopy. Moreover, the use of Magill forceps is markedly challenging or nearly unfeasible in this context, especially in pediatric cases. Furthermore, the substantial blade size of video laryngoscopes may restrict their applicability in individuals with limited oral apertures. This study aimed to review the literature on video laryngoscopy, discuss its clinical role in nasotracheal intubation, and address the challenges that anesthesiologists may encounter during the intubation process.

Durability and Damage Tolerance Analysis Approaches for Wind Turbine Blade Trailing Edge Life Prediction: A Technical Review

The size of wind turbine blades is increasing rapidly, and they are being installed in remote offshore locations. Consequently, it is essential to focus on improving the design and maintenance procedures in the blade industry to meet the growing demand. Of particular concern is the long-term operational performance of the wind turbine blade trailing edge. In this paper, we discuss the application of durability and damage tolerance analysis (DADTA) approaches to trailing edge service life prediction. DADTA is mandated in the aerospace sector to support airworthiness certification and to provide an updated life prediction of the structure based on the different stages of their service life. The DADTA framework has two main parts: durability and damage tolerance analysis. The durability part uses a structural fatigue approach based on a damage accumulation method during the initial design phase to predict the lifespan of a structure without defects. On the other hand, the damage tolerance analysis part uses a fracture mechanics approach and a damage growth method to update the lifespan prediction of a structure during the operation stages. This is achieved by utilizing sensors and inspection data as inputs while the structure is in service. Both these methods are comprehensive and have merits; however, their broad adoption in the wind turbine blade industry is still lacking. The current paper provides an extensive review of these methods and shows how these can be applied to the wind turbine blade industry, specifically for predicting the structural design life of the trailing edge of composite wind turbine blades. The review includes (a) defining wind turbine trailing edge failure modes, (b) trailing edge design procedures, and (c) a detailed discussion of the application of durability and damage tolerance analysis for trailing edge life prediction. Overall, this review paper would be of special interest to blade designers and would guide researchers and engineers interested in life prediction methodologies based on DADTA approaches for wind turbine blades.

The effects of exogenous tyrosine supplement on spinach (Spinacia oleracea L.) cultivation under lithium stress

In this study, the effects of exogenous Tyrosine (Tyr: 2.5 mM) application on the variations of growth rate parameters, enzymatic and non-enzymatic constituents, oxidative stress, and mineral content under lithium-applied (Li1: 6.44 mM; Li2: 19.32 mM) seedlings of the Anlani F1 spinach cultivar were investigated. Results showed that a higher Li led to a significant reduction in the growth rate parameters including shoot, root, and leaf length, the fresh weight of shoot, root, and leaf, and leaf blade sizes, whereas a lower Li dose resulted in an increase in those parameters. In contrast, the Tyr supply to the Li-applied seedlings resulted in a rise in these measured parameters. Similarly, chlorophyll and polyphenol contents and PAL, APX, CAT, POD, and SOD activities were higher in all exogenous Tyr-treated groups, including lithium-treated groups. Whilst nitrate content was higher in the Li-applied seedlings, NR activity was lower. Also, MDA and H2O2 were found to be higher in the Li-applied group, but exogenous Tyr supplements reduced their levels in the seedlings. Li, Ca, Na, Cl, Mn, Fe, Ni, Cu, and Zn accumulation were induced by Li doses and Tyr applications together with Li, but Tyr applications alone reduced all of their levels. Also, exogenous Try supplementations to the Li-applied group caused an important decline in the Li accumulation. As a result, a higher Li dose exhibited a negative effect on the growth rate, chemical constituent, and antioxidant compounds of the Anlani F1 spinach cultivar, but exogenous Tyr supplement improved those examined traits in the Li-applied seedlings.

Design and experiment of a soybean shaftless spiral seed discharge and seed delivery device

When the driven stubble-breaking and anti-blocking no-till planter operates in the Southwest China, the stubble-breaking blades will impact with the ground as they cut through the soil and straw stubble, causing the planter to vibrate. This results in poor performances of the seed discharge by seed discharger and the seed guide by the seed guide tube. Based on the principle of spiral conveying, a soybean shaftless spiral seed discharge and seed delivery device was designed. The optimum seed filling size and speed range of the spiral blade were obtained by analyzing the size, force, and motion of soybean seeds of "ZhongHuang 37". The quadratic regression orthogonal rotation test and response surface method were used to analyze the operating parameters of the shaftless spiral seed discharge and seed delivery device by joint EDEM (Discrete Element Method)-RecurDyn simulation. The optimum parameters were obtained: the spacing of spiral was 11.4 mm, spiral outer radius was 5.5 mm, spiral inner radius was 2.9 mm and rotation speed was 10.4 r·s−1. Based on simulation and optimization results, the device was trialed and its field performance was tested. The results showed that at a surface slope of 16.1°, an average surface flatness of 8.9 cm, an average planter vibration frequency of 75.2 Hz, and an average amplitude of 7.2 mm, the average seeding qualification index, multiple index, missing seeding index, and damage index of the shaftless spiral seed discharge and seed delivery device were 92.6%, 5.03%, 2.4% and 0.92%, respectively, which were in line with the local agronomic requirements. The designed soybean shaftless spiral seed discharge and seed delivery device meets the requirements of the quality of no-till seeding and can provide a reference for the design and improvement of seed discharger and seed guide tube under poor ground leveling and long-distance seed delivery conditions.