Entry Angle Research Articles

Exploring the load characteristics and structural responses of a high-speed vehicle entering water

The process of a trans-medium vehicle crossing from air into water is referred to as water entry. It involves the interplay of air, water, and the vehicle and is a non-stationary process. In this study, we use the coupled Eulerian–Lagrangian method, along with the constitutive Johnson–Cook model and the model of cumulative damage-induced failure, to describe the dynamic plastic flow and fracture-related behavior of the vehicle shell, and use it to develop a method to numerically simulate the process of a high-speed vehicle entering water. When it contacts with water, the elasticity of the medium prompted a significant deflection and deformation in the central area of the head of the vehicle shell. As deformation approached its limit, tensile fractures occurred that caused the shell of the head to separate from the main body. Changes in its angle of water entry influenced the fracture process of the shell. The symmetric, parabolic bending deformation of the head of the vehicle shell occurred around its central axis. The time taken by different types of vehicle heads to fail varied significantly, leading to marked differences in their peak deformation. We determined the quantitative relationship between the dimensionless factor χ and the velocity of water entry, using it to estimate the ultimate water entry velocity for vehicles of different sizes but composed of the same material.

Stability simulation analysis of targeted puncture in L4/5 intervertebral space for PELD surgery.

Introduction: The application prospects of percutaneous endoscopic lumbar discectomy (PELD) as a minimally invasive spinal surgery method in the treatment of lumbar disc herniation are extensive. This study aims to find the optimal entry angle for the trephine at the L4/5 intervertebral space, which causes less lumbar damage and has greater postoperative stability. To achieve this, we conduct a three-dimensional simulated analysis of the degree of damage caused by targeted puncture-based trephine osteotomy on the lumbar spine. Methods: We gathered clinical CT data from patients to construct a lumbar model. This model was used to simulate and analyze the variations in trephine osteotomy volume resulting from targeted punctures at the L4/5 interspace. Furthermore, according to these variations in osteotomy volume, we created Finite Element Analysis (FEA) models specifically for the trephine osteotomy procedure. We then applied mechanical loads to conduct range of motion and von Mises stress analyses on the lumbar motion unit. Results: In percutaneous endoscopic interlaminar discectomy, the smallest osteotomy volume occurred with a 20° entry angle, close to the base of the spinous process. The volume increased at 30° and reached its largest at 40°. In percutaneous transforaminal endoscopic discectomy, the largest osteotomy volume was observed with a 50° entry angle, passing through the facet joints, with smaller volumes at 60° and the smallest at 70°. In FEA, M6 exhibited the most notable biomechanical decline, particularly during posterior extension and right rotation. M2 and M3 showed significant differences primarily in rotation, whereas the differences between M3 and M4 were most evident in posterior extension and right rotation. M5 displayed their highest stress levels primarily in posterior extension, with significant variations observed in right rotation alongside M4. Conclusion: The appropriate selection of entry sites can reduce lumbar damage and increase stability. We suggest employing targeted punctures at a 30° angle for PEID and at a 60° angle for PTED at the L4/5 intervertebral space. Additionally, reducing the degree of facet joint damage is crucial to enhance postoperative stability in lumbar vertebral motion units.

Investigation of the tool flank wear influence on cutter-workpiece engagement and cutting force in micro milling processes

Cutting force modeling is essential for comprehending the dynamic mechanics of the micro-milling process. Accurate calculation of the cutter-workpiece engagement is crucial for predicting cutting force accurately. This study proposes an accurate analytical model of cutter-workpiece engagement that comprehensively incorporates tool flank wear, tool edge radius, and tool runout for predicting cutting forces in the micro-milling process. Based on the actual tool radius model, which takes into account tool flank wear and tool edge radius, a fast real-time online method for accurately calculating the entry and exit angles is presented. This method involves the trochoidal trajectories of the current cutting edge and all passing cutting edges from the previous cycle under the influence of tool runout. Then the cutter-workpiece engagement is determined. Based on this, the cutting force is predicted combined with instantaneous uncut chip thickness and cutting force coefficients considering tool flank wear and tool runout. Through micro-end milling experiments, the validity of the cutting force model is confirmed. The statistical analysis of the predicted cutting forces further demonstrates the effectiveness of accounting for the impact of tool flank wear on the cutting forces throughout the entire micro-milling process. Through case analysis, it is concluded that tool flank wear leads to increased cutter-workpiece engagement and significantly affects the cutting forces in three directions. This work could offer a theoretical foundation and practical guidance for predicting tool life and controlling surface quality during the machining process.

Influence of Pre-Shooting Activity on Three-Points Jump Shot Parameters Between Junior and Senior Regional Level Basketball Players

The aims of this study were: 1. to investigate the influence of pre-shooting activity on the three-point jump shot entry angle and release time in regional level basketball players; 2. to examine age related differences in these parameters between juniors and seniors. Thirty three perimeter players , were assigned to juniors (n=16, age=17.34±0.54 years; height=191.3±8.18 cm; weight= 77.08±7.41 training experience=6.75±2.30 years) and seniors (n=17, age=22.79±4.47 years; height =194.4±7.47 cm; weight= 80.42±7.45d; training experience= 12.18±3.17 years) had three sets of 5 shots, with a different preparatory phase for every set: 1. spot shot, 2. after two forward steps, or 3. after one dribble. Only successful shots (n= 233) were analyzed. The difference between groups was determined with ANOVA, while the differences in shot accuracy were determined by the chi-square test. Study results reported no statistically significant differences in entry angle and release time for 3 different pre-shooting patterns. Seniors had significantly higher shooting accuracy (X2=3.097; p=0.048, φ=-0.089) higher entry angle (p < 0.001) and lower release time (p < 0.001) than juniors for all successful shots combined, and significantly higher (p < 0.001) entry angle for every set independently. Significant difference in shooting accuracy with medium effect size (X2= 6.645; p=0.010, φ=-0.20) was observed in shots after movement. Seniors had statistically lower release time for set 1 (p=0.004) and 2 (p=0.002) independently. Age-related group differences in shooting parameters should be considered to optimize training prescription for basketball players.

The impact of the grinding angle of the soil dredging tool on its performance

This investigation explores the optimization of the backhoe blade's entry angle, addressing its crucial role in enhancing energy efficiency and operational effectiveness in subsoil manipulation - a fundamental aspect of agricultural tillage technologies. Utilizing an integrated approach that combines detailed field experiments with robust theoretical simulations, the study methodically quantifies the effects of angular variations on energy demands and mechanical performance during soil dredging. Our results reveal precise angular configurations that offer optimal reductions in energy use while significantly improving the disruption and aeration of the subsoil layer. This optimization contributes directly to the development of advanced, precision-engineered agricultural implements aimed at boosting sustainability and productivity in farming practices. Furthermore, the outcomes of this research provide pivotal insights into soil health management strategies, potentially influencing crop yield through improved root penetration and water absorption. These findings are expected to serve as a benchmark for future innovations in agricultural machinery design, aligning with global trends towards more sustainable agricultural practices and enhanced food security. This study sets a new standard for agricultural tool engineering, paving the way for transformative changes in the sector.

Effects of Differences in Epidural Needle Entry Point and Angle of Rotation of Needle Hub on the Onset and Duration of Sensory Blockade in Lower Limb Orthopaedic Surgeries: A Randomised Controlled Trial

Introduction: Epidural anaesthesia is a boon for providing prolonged analgesia for postoperative pain relief. The influence of epidural needle insertion on the onset of the block, which has not been studied previously, is significant. Aim: To analyse the effect of epidural needle entry and rotation of the needle on the onset and duration of the block. Materials and Methods: This double-blinded randomised controlled trial was conducted at the Department of Anaesthesiology, SRM Institute of Science and Technology, Chennai, Tamil Nadu, India from March 2020 to August 2021 on 70 patients undergoing leg and ankle surgeries. They were randomised into Group-ML (midline approach) and Group-PM (paramedian approach). In Group-ML, midline epidural needle entry was followed by catheter insertion. In Group-PM, the needle entry was paramedian, and the bevel was turned 45º towards the surgical site for catheter insertion. A 10 mL of 0.5% bupivacaine was administered. Postoperatively, epidural infusion was initiated using 0.125% bupivacaine with 2 μg/mL fentanyl. The time taken for catheter placement, onset of motor and sensory blockade, maximum sensory level attained, duration of sensory blockade, consumption of local anaesthetics, haemodynamic profile, and the need for rescue analgesia were monitored. Continuous data were analysed using the Student's t-test, and categorical data were analysed using the Chi-squared test with International Business Machines (IBM) statistical product and service solutions software version 27.0 Results: Both groups were comparable with respect to demographics. The mean age in Group-ML was 40.9±25.93 years, while in Group-PM it was 41.028±20.576 years, with a p-value of 0.981. The mean BMI in Group-ML was 24.91±2.998 kg/m2 , while in Group-PM it was 24.96±2.527 kg/m2 , which was statistically insignificant with a p-value of 0.944. A total of 21 males in Group-ML and 28 males in Group-PM participated in the study; the distribution was found to be statistically insignificant with a p-value of 0.067. The time taken for the placement of the epidural catheter was around 288 seconds in Group-ML and 322 seconds in Group-PM, with a p-value of 0.0035. The onset of sensory block was around 17 minutes in Group-ML and 13 minutes in Group-PM, respectively, with a p-value of 0.0001. The duration of sensory block or the time taken for two-segment regression of level was around 102 minutes and 128 minutes in Group-ML and Group-PM, respectively (p-value 0.0001). The rescue analgesic was required in seven patients of Group-ML and none in Group-PM, with a p-value of 0.005. The haemodynamic profile intra and postoperatively and postoperative VAS score were statistically insignificant between the groups. Conclusion: The paramedian approach and epidural catheter insertion with the needle rotated at an angle of 45º towards the surgical side provide a rapid onset of the sensory and motor block with extended duration of the sensory blockade and reduced consumption of local anaesthetics.

Impact of entrance angle of rectangular openings of centrifugal multivortex device on its classification efficiency

Air classification is a common process in many industries. The paper presents an analysis of the operation of a centrifugal multivortex classifier designed to separate solid particles. The classification process of gas-solid system is observed between the outer pipe and the inner pipe, which has rectangular openings that provide the formation of the stable vortex system. The purpose of this work is to study the influence of the entrance angle of rectangular openings on the classification effectiveness of the device. The results show that the maximum effectiveness in the classification of particles larger than 40 μm is achieved at an angle of 0.8 and a gas flow speed of 16 m/s, providing an effectiveness of 69.6%. Increasing the speed at the inlet to the device improves the effectiveness, since the vortex structure in the interpipe space becomes more stable. It is recommended to select the classifier with the largest entrance angle of rectangular openings, since the lowest pressure loss is achieved. Changing the entrance angle of rectangular openings of the device has practically no effect on the effectiveness of particle classification.

The influence of deviation in the centroid and entry angle of the bullet on its motion inside the barrel

The influence of deviation in the centroid and entry angle of the bullet on its motion inside the barrel

Analysis of input angles of fibrous masses of exhaust steam devices

In existing spinning systems when processing natural, artificial and synthetic fibers into yarn, the main task of the technological process is to obtain sliver, roving and yarn that is uniform in structure and properties by folding and drawing. The article proposes a theoretical analysis of the entry angles of the fibrous masses of the exhaust steam of an exhaust device. The entry angles of the fibrous masses of the existing and new design of the pressure roller with reduced diameters were compared.

Effects of Die Entry Angle on the Mechanical Properties of Extruded Lead Alloy

The use of lead to produce wire, power cable sheathing, guide plates, and other wide-range applications require fine-grain structures. Researchers adopted severe plastic deformation, as a means of attaining ultra-fine grain structure. However, this technique is rather expensive and time-consuming. Thus, this study is focused on the application of a simple extrusion technique to achieve fine grain structure in the lead alloy by using different die entry angles to study the microstructural and mechanical properties of lead alloy. Lead alloy samples were cast into cylindrical billets in a sand mould, machined, and tapered at the edge to ease entry into the die for the extrusion process. The die tools were made of mild steel with die entry angles of 15°, 30°, 45°, 60°, 75°, and 90°. Subsequently, the extrusion was performed with the aid of a hydraulic press machine that provided pressure on a cylindrical punch and forced the billet through the extrusion die. The mechanical and microstructural properties were studied, using the micro-hardness tester and metallurgical microscope, respectively. The results show that the maximum extrusion stress of 70 MPa of lead alloy occurred at a die entry angle of 45°, which is three times that of the conventional alloy (18 MPa) with crystal clustering and fine microstructure. The ductility of lead alloy improved when processed at a 60° die entry angle with extrusion stress of 63.3 MPa, with no significant increase in hardness with die entry angles (7.7-9.0 HV). The grains show an appreciable reduction in size and enhanced surface finish

Hydrodynamics and stability of oblique water entry in waves

Waves, a constant presence in the ocean, significantly influence the stability of a vehicle's water entry. In the present work, the effects of waves on the water entry of a vehicle equipped with a cavitator, utilizing the Computational Fluid Dynamics (CFD) method. The Stokes V wave theory serves as the basis for wave simulations, while the moving computational domain method is used to realize the motion of the vehicle. The water entry process is most influenced by waves at the peak point of wave inclination. This research delves into the impacts and underlying mechanisms of wave height, entry angle, and speed on the water-entry process, particularly focusing on the range of wave influence. Re-entry may occur when the entry angle is smaller than the maximum wave inclination. Under such circumstances, the vehicle's motion could become more erratic, potentially leading to re-entry failure. Consequently, two critical angles are defined: one where re-entry is likely to occur, and another where re-entry is inevitable. The influences of wave parameters and entry angle on the possibility of re-entry are investigated. The proposed critical angles and their calculation method lay the groundwork for future research aimed at ensuring safe water entry for vehicles amid waves.

Controllable generation of core-shell composite droplets in a conical inlet double-focus microchannel

In this paper, a double-focused conical inlet axisymmetric structure with double acceleration is proposed and the evolution of composite core-shell droplets is calculated using the volume of fluid (VOF) method, focusing on the size and droplet formation frequency of composite core-shell droplets as well as the quality control method. The results show that dripping and jetting regimes occur in the channel, and the generation period and flow distribution under the two mechanisms are investigated accordingly. The effect of local geometry on the evolution of composite droplets in the core-shell is investigated and analyzed using the composite droplet size, frequency, maximum extended length, and core droplet relative offset rate at the initial stage. It is found that changing the entrance angle can achieve the regulation of droplet size to a certain extent. With the increase of dimensionless width of the collection channel, the core-shell composite droplets size shows an overall increasing trend and is inversely proportional to the outer phase capillary number. Finally, a quality control method for composite droplet formation based on the maximum relative offset rate of core droplets is proposed for the purpose of controlling the integrity of composite droplets.

Implantation accuracy and operative variables in robot-assisted stereoelectroencephalography.

The stereoelectroencephalography (SEEG) procedure provides a unique 3D overview of the seizure-onset zone. Although the success of SEEG relies on the accuracy of depth electrode implantation, few studies have investigated how different implantation techniques and operative variables affect accuracy. This study examined the effect of two different electrode implantation techniques (external vs internal stylet) on implantation accuracy while controlling for other operative variables. The implantation accuracy of 508 depth electrodes from 39 SEEG cases was measured after coregistration of postimplantation CT or MR images with planned trajectories. Two different implantation techniques were compared: preset length with internal stylet use and measured length with external stylet use. Correlations between implantation accuracy and technique type, entry angle, intended implantation depth, and other operative variables were determined statistically using multiple regression analysis. Multiple regression analysis showed that the internal stylet technique exhibited a larger target radial error (p = 0.046) and angular deviation (p = 0.039) with a smaller depth error (p < 0.001) than the external stylet technique. Entry angle and implantation depth were positively correlated with target radial error (p = 0.007 and < 0.001, respectively) only for the internal stylet technique. Better target radial accuracy was achieved when an external stylet was used to open the intraparenchymal pathway for the depth electrode. In addition, more oblique trajectories were equally accurate to orthogonal ones with the usage of an external stylet, while more oblique trajectories were associated with larger target radial errors with the usage of an internal stylet (without an external stylet).

Coronary CT Angiography-based Morphologic Index for Predicting Hemodynamically Significant Coronary Stenosis.

Purpose To develop a new coronary CT angiography (CCTA)-based index, α×LL/MLD4, that considers lesion entrance angle (α) in addition to lesion length (LL) and minimal lumen diameter (MLD) and to evaluate its efficacy in predicting hemodynamically significant coronary stenosis compared with invasive coronary angiography (ICA)-derived fractional flow reserve (FFR). Materials and Methods This prospective study enrolled participants (September 2016-March 2020) from two centers who underwent CCTA followed by ICA (ClinicalTrials.gov identifier: NCT03054324). CCTA images were processed semiautomatically to measure LL, MLD, and α for calculating α×LL/MLD4. Diagnostic performance and accuracy of α×LL/MLD4 and LL/MLD4 in detecting hemodynamically significant coronary stenosis were compared against the reference standard (invasive FFR ≤ 0.80). Results In total, 133 participants (mean age, 63 years ± 9 [SD]; 99 [74%] men) with 210 stenosed coronary arteries were analyzed. Median α×LL/MLD4 was 54.0 degree/mm3 (IQR, 25.3-128.7) in participants with invasive FFR of 0.80 or less and 6.7 degree/mm3 (IQR, 3.3-12.8) in participants with invasive FFR of more than 0.80 (P < .001). The per-vessel accuracy, sensitivity, specificity, positive predictive value, and negative predictive value for discriminating ischemic lesions were 86.2%, 83.1%, 88.4%, 84.1%, and 87.7% for α×LL/MLD4 and 80.5%, 66.3%, 90.9%, 84.3%, and 78.6% for LL/MLD4, respectively. Area under the receiver operating characteristic curve for discriminating hemodynamically significant stenosis was 0.93 for α×LL/MLD4, which was significantly greater than the values of 0.84 for LL/MLD4 and 0.63 for diameter stenosis (both P < .001). Conclusion The new morphologic index, α×LL/MLD4, incorporating lesion entrance angle achieved higher diagnostic performance in detecting hemodynamically significant lesions compared with diameter stenosis and LL/MLD4. Keywords: CT Angiography, Cardiac, Coronary Arteries, Ischemia, Infarction, Technology Assessment Clinical trial registration no. NCT03054324 Supplemental material is available for this article. © RSNA, 2023 See also the commentary by Fairbairn and Nørgaard in this issue.

Machining damage mechanism in end milling of the GH4099 superalloy honeycomb core with ice fixation

Superalloy honeycomb cores have the advantages of high temperature resistance, light weight, and high specific strength, and are widely used in aerospace and defense industries. However, honeycomb cores have thin-walled and porous structural characteristics, the contact state between the tool and the honeycomb wall is variable during cutting, which is prone to machining damage and will adversely affect subsequent assembly and service performance. In this paper, GH4099 superalloy honeycomb core was taken as the research object. First, through the force analysis of the honeycomb wall, the difference of honeycomb wall damage mechanism in end milling without and with ice fixation was revealed. Next, an instantaneous rotation entrance angle analytical model taking into account honeycomb structure, tool size, and cutting parameters was established to characterize the contact state between the tool and the honeycomb wall. Finally, the milling experiment of superalloy honeycomb cores with ice fixation was carried out, and the maximum deformation displacement and damage area were used to quantify the degree of machining damage. The results indicated that the closer the rotation entrance angle is to 180°, or the larger the cutting width, the worse the machining quality of the honeycomb wall. Controlling the rotation entrance angle θREA＜90° and the cutting width ae＜0.80 mm is conducive to enhancing the shearing effect of the cutting edge on the honeycomb wall, which can effectively reduce the machining damage of honeycomb wall, and provide technical guidance for the optimization of low-damage machining processes of thin-walled porous metal materials.

Analytical method to extract tool workpiece engagement from CAM data for five-axis machining stability prediction

Ball end milling cutters are commonly used for precision machining of complex curved parts in five axis CNC systems. To solve the problem of difficulty in adjusting the spindle speed to achieve stable milling during the five axis milling process of ball end cutters, this paper presents an analytical method for extracting the tool-workpiece engagement (TWE) from computer-aided manufacturing (CAM) data. This method extracts the TWE between the end portion of the ball-end mill and the surface of the workpiece during the processing of free-form surfaces, including slotting, first cutting, and following cutting. Further, the TWE extracted by this method is applied for constructing the cutting force model. The entry and exit angles for each of the micro-element cutting edges under different tool postures are obtained through the conversion matrix, and an efficient full discretization method is used for predicting the stability of the five-axis machining in the slotting mode. Finally, the accuracy and efficiency of the analytical method are verified through simulation and experimentation. The experimental results show that the efficiency of the proposed method increases by about 69% when compared to the arc-surface intersection method and that the predicted value of the five-axis machining stability shows good agreement with the experimental results.

A New Method for Common Femoral Arterial Access Using a Mixed Reality-Assisted Technique on a Phantom Model.

The purpose of this study was to investigate the technical feasibility and usability of a mixed reality (MiR)-assisted common femoral arterial (CFA) access technique using a sonography-assisted registration method. A total of 60 CFA punctures were performed on a phantom model by 2 observers. Thirty punctures were performed using MiR (MiR group) and 30 punctures were performed using a conventional sonography-guided access procedure (control group). In the MiR group, a virtual object was created based on a computed tomography (CT) angiography scan of the model and registered to the physical patient in an MiR environment utilizing a software prototype that allowed registration based on a sonography scan. Positional error assessment encompassed 4 measurements using cone beam CT scans: (1) distance of the needle tip to the centerline, (2) distance of the needle entry site from the mid-level of the ostium of the profound femoral artery, (3) angle of entry of the needle in coronal, and (4) sagittal planes. Technical success rates as well as positional errors were compared between both groups. In addition, the usability of the system was assessed according to the system usability scale (SUS). Technical success was 96.7% and 100% in the MiR and control groups, respectively. The median distance between the needle tip and the centerline was 3.0 (interquartile range [IQR]: 2.0-4.6) in the MiR group and 3.2 mm (IQR: 2.3-3.9) (p=0.63) in the control group. Similarly, the median distance from the needle entry site to the mid-level of the ostium of the profound femoral artery was 3.0 mm (IQR: 2.0-5.0) in the MiR group and 4.5 mm (IQR: 2.0-7.8) (p=0.18) in the control group. The median coronal angles of needle entry were 7.5° (IQR: 6-11) and 6° (IQR: 2-12) (p=0.13), and the median sagittal angles were 50° (IQR: 47-51) and 51° (IQR: 50-55) (p<0.01) in the MiR and control groups, respectively. The mean SUS score provided by both observers was 51.3. The feasibility of an MiR-assisted CFA access technique could be demonstrated on a phantom model. Further studies are needed to investigate the technique beyond phantom model experiments and in different anatomical settings. This study demonstrates the technical feasibility of a Mixed-Reality-assisted common femoral arterial access procedure on a phantom model. The positional accuracy was comparable to a conventional sonography-guided technique. However, there are several limitations that need to be resolved prior to potential implementation into clinical practice. Further studies are needed to investigate its performance beyond phantom model experiments and the prototypical application requires further technical refinement to increase its usability.

Mechanistic modeling considering bottom edge cutting effect and material anisotropy during end milling of aluminum honeycomb core

In the end milling of aluminum honeycomb core, the bottom edge of the cutter and the feed direction of the cutter will have a significant impact on the surface machining quality. If the above two factors are neglected in mechanistic modeling, the surface machining quality will be difficult to improve. In this paper, a mechanistic model considering the bottom edge cutting effect and the anisotropic characteristics of the material is firstly proposed to accurately predict cutting forces. Based on the contact relationship between the bottom edge and the honeycomb wall, a cutting force model of the bottom edge is developed, which includes the geometric characteristics of the bottom edge and the thin-walled edge cutting angle. For anisotropic characteristics of the material, a dynamic variation model of the entry and exit angles in any cutting direction is established on the basis of the structural model of the honeycomb core and cutting edge trajectory. The proposed mechanistic model was validated through a series of milling experiments. The results indicate that this model can be used to predict the cutting force of various parts of the cutter (including bottom and flank edges) and any feed direction.

Design and experiment of furrow side pick-up soil blade for wheat strip-till planter using the discrete element method

The strip rotary tillage method effectively reduces the occurrence of straw clogging and creates a favorable seed bed environment. However, the mixture of crushed straw and soil in the seeding area results in inadequate seed-soil contact following compaction by the press wheels. A chisel-type opener furrow side pick-up blade was proposed to improve seed-soil contact by picking up wet soil from the furrow's side. The discrete element method was used to investigate the impact of earth blade surface parameters on soil dynamics. The key factors of the blade, including forward velocity, endpoint tangent angle, and angle of soil entry, were determined through theoretical analysis. Soil cover thickness and straw ratio in the seed furrow were evaluated using orthogonal rotation regression tests. The results show that the endpoint tangent angle and angle of soil entry have the greatest influence on soil cover thickness, while the angle of soil entry has the greatest influence on the straw ratio. The optimal values for the forward velocity, endpoint tangent angle, and angle of soil entry are 4.86 km/h, 107.17°, and 5.46°, respectively, resulting in a soil cover thickness of 40 mm and a straw ratio of 21.46%. Confirmatory soil bin tests showed similar results, with a soil cover thickness of 40.4 mm and a straw ratio of 18.03%. These results provide a viable solution for improving seed-soil contact after strip rotary tillage planter seeding.

Investigating the effects of air inlet jet on the performance of solar still: A comprehensive numerical study

Solar stills are a simple method of producing potable water, but their low efficiency makes them insufficient for meeting daily water needs. This study aims to improve the efficiency of simple solar stills (simple SS) by investigating the effect of an air inlet jet. Factors such as air velocity, entrance angle, and inlet and outlet location were studied. The effect of inlet velocity was studied for air inlet velocities of 1, 2, 3, 4, 5, and 9 m/s, and the effect of inlet angle was studied under six different angles ranging from −45 to +45 degrees. Results showed at Uin=5m/s for the case where the glass cover and basin water were in the highest temperature difference when the inlet was located on the left wall (left-inlet mode), water production rate (ṁ) and heat transfer rate (Nu) improved by %125 and %126, respectively, and for the right-inlet mode, ṁ and Nu improved by %209 and %205, respectively. For an angled inlet, at Uin=9m/s with inlet angle of +15 degrees, for left-inlet mode, ṁ and Nu improved by 211 % and 207 %, respectively, And for right-inlet mode, the ṁ and Nu improved by up to 264 % and 257 %, respectively.