Step Angle Research Articles

Research on the Method of Determining Highway Truck Load Limit Based on Image Processing

Over-limit transportation is the leading cause of highway pavement diseases and traffic accidents. The Ministry of Transport of China has determined the weight limit for different trucks entering the highway based on the number of truck axles and the coupling method. However, because determining the truck weight limit is more complicated, the current work is mainly done manually by the toll station staff at the expressway entrance, and the recognition speed is slow Cand the recognition result is inaccurate. In response to this problem, we first analyzed and established the relationship between the number of axles and the position distribution, and the truck weight limit. Based on the above, we developed a circle detection method with an improved Hough and CURE algorithm as the core to identify truck wheel axles. We collect 100 test images at the expressway entrance and use 50 of them to perform detection experiments to determine the radius step, angle step, and the maximum and minimum circle values during the detection process. After using the entire data set, comparing the hough algorithm, the improved Hough algorithm, and our proposed method, the results show that our proposed method has higher accuracy and efficiency.

An assessment of residual stresses and micro-structure during single point incremental forming of commercially pure titanium used in biomedical applications

Single point incremental forming (SPIF) is a branch of incremental sheet forming where a very small portion of the sheet is deformed plastically at any moment. The highly localized point deformation is done by a simple hemispherical tool, whose path is numerically monitored by a Computer numerical control (CNC) machine, performs this progressive extremely localized deformation. Since no die is required during forming, highly customized and user-oriented sheet metal products can be manufactured employing the process. SPIF can be readily employed in the manufacturing of customized orthopaedic implants and braces, e.g., cranial implants, ankle implants, elbow and knee support braces. The forming of these sheets through SPIF would results in the generation of residual stresses in the sheet metal. With time and other physical factors, these residual stresses would be relieved resulting in dimensional inaccuracy. This inaccuracy is highly detrimental in the case of implants and highly undesirable for supporting braces. The objective of this work is to investigate, experimentally, the state and magnitude of residual stresses on commercially pure titanium grade 2 by SPIF for biomedical applications. The important process parameters: forming angle and incremental step depth are used for this investigation in the present study. The X-ray diffraction technique was used for the experimental measurements of the residual stresses. Microstructural behaviour of the final product at different incremental step depth and forming angles are also observed by EBSD (Electron backscattered diffraction) technique. The experimental findings showed the formation of increased tensile residual stresseswith an increase in incremental step depth and steepness of forming angles.

基于脱靶量的水下目标激光扫描探测模型

Blue-green laser has broad application prospects in non-acoustic detection of underwater targets. However, the existing detection models have not considered the problem of matching the detection probability with the self-guided system. A target detection model of underwater laser scanning detecting system was established based on undershoot distance to match the guiding precision. The simulation results shows that an increasing undershoot distance needs an increasing emit angle to get high detection probability at a certain emit frequency, which however leads to a decreasing acting time for the following system. In addition, an increasing undershoot distance needs an increasing emit frequency and a decreasing step angle to avoid missing the target. Finally, the simulation provides an optimal range for undershoot distance and system parameter. The model and the simulation results provide theoretic basis for the matching up design of guiding system and detecting system.

A Programmable Impedance Tuner with a High Resolution Using a 0.18-um CMOS SOI Process for Improved Linearity

In this paper, a novel coupler/reflection-type programmable electronic impedance tuner combined with switches that were fabricated by a 0.18-um complementary metal–oxide–semiconductor (CMOS) silicon-on-insulator (SOI) process is proposed for replacement of the conventional mechanical tuner in power amplifier (PA) load-pull test. By employing the multi-stacked field-effect transistors (FETs) as a single-branch switch, the proposed tuner has the advantage of precise impedance variation with systematic and magnitude and phase adjustment. Additionally, it led to high standing wave ratio (SWR) coverage and a good impedance resolution with a high power handling capability. Furthermore, the double-branch based on multi-stacked FET was applied to switches for additional enhancement of the intermodulation distortion (IMD) performance through the mitigated drain-source voltage of the single-FET. Drawing upon the measurement results, we demonstrated that SWR changed from 2 to 6 sequentially with a 12–15° phase angle step over a mid/high-band range of a 1.5–2.1 GHz band for 3G/4G handset application. In addition, the PA load-pull measurement results obtained using the proposed tuners verified their practicality and competitive performance with mechanical tuners. Finally, the measured linearity using the double-branch switch demonstrated the good IMD3 performance of −78 dBc, and this result is noteworthy when compared with conventional electronic impedance tuners.

Development of a step drill for minimization of delamination and uncut in drilling carbon fiber reinforced plastics (CFRP)

A step drill is developed to minimize delamination and uncut fiber in machining carbon fiber reinforced plastics (CFRP), which consists of two parts, a core part and a step part. The core part is designed to minimize the thrust force by controlling core diameter. The step part is designed to remove the delamination generated by core part without 2nd delamination, which consists of step angle. The effect of feed rate and spindle speed on the performance of drilling also investigated. To remove the uncut fibers properly, the higher rake angle of step part is applied. By measurement of thrust force, it is found that the delamination can be reduce when smaller thrust force is generated. As a result, a step drill is designed for less generation of delamination and uncut fiber for drilling T700 3K CFRP.

How Do Spatiotemporal Parameters and Lower-Body Stiffness Change with Increased Running Velocity? A Comparison Between Novice and Elite Level Runners.

This study aimed to examine the effect of running velocity on spatiotemporal parameters and lower-body stiffness of endurance runners, and the influence of the performance level on those adaptations. Twenty-two male runners (novice [NR], n = 12, and elite runners [ER], n = 10) performed an incremental running test with a total of 5 different running velocities (10, 12, 14, 16, 18 km/h). Each condition lasted 1 min (30 s acclimatization period, and 30 s recording period). Spatiotemporal parameters were measured using the OptoGait system. Vertical (Kvert) and leg (Kleg) stiffness were calculated according to the sine-wave method. A repeated measures ANOVA (2 x 5, group x velocities) revealed significant adaptations (p < 0.05) to increased velocity in all spatiotemporal parameters and Kvert in both NR and ER. ER showed a greater flight time (FT) and step angle (at 18 km/h) (p < 0.05), longer step length (SL) and lower step frequency (SF) (p < 0.05), whereas no between-group differences were found in contact time (CT) nor in the sub-phases during CT at any speed (p ≥ 0.05). ER also showed lower Kvert values at every running velocity (p < 0.05), and no differences in Kleg (p ≥ 0.05). In conclusion, lower SF and Kvert and, thereby, longer FT and SL, seem to be the main spatiotemporal characteristics of high-level runners compared to their low-level counterparts.

Diffusion tensor imaging of the human thigh: consideration of DTI-based fiber tracking stop criteria.

To consider the tract-based analysis of DTI parameters in human muscle by assessing different fiber tracking stop criteria settings on diffusion parameters. 30 healthy volunteers underwent a 3T MRI. Diffusion-weighted images were acquired to perform DTI and fiber tracking analysis for six thigh muscles. Whole thigh muscles were evaluated by fiber tractography using different fiber tracking stop parameters [FA (0.01-0.15) to (0.4-0.99); angle 10°-30°, step size 0.75mm, 1.5mm, 3mm]. Diffusion and tractography-derived parameters per stop criterion were compared using a repeated measure ANOVA including Bonferroni-corrected post hoc tests. We found significant differences in all examined diffusion parameters between different stop criteria (main effect p < 0.001). We showed different influence of tracking parameters on diffusion parameters in examined muscles (main effect p ≤ 0.001). Statistically significant differences in fiber tracking results using different stop criteria were shown. Fiber tracking stop criteria do have an important influence on study results and should be considered in the development of study protocols and comparison of studies. We recommend a FA minimum of 0.10 and a step size lower than voxel size, e.g., a half with a constant ratio between step size and angle of 10°/mm.

Altered rodent gait characteristics after ~35 days in orbit aboard the International Space Station

The long-term adaptations to microgravity and other spaceflight challenges within the confines of a spacecraft, and readaptations to weight-bearing upon reaching a destination, are unclear. While post-flight gait change in astronauts have been well documented and reflect multi-system deficits, no data from rodents have been collected. Thus, the purpose of this study was to evaluate gait changes in response to spaceflight. A prospective collection of gait data was collected on 3 groups of mice: those who spent~35 days in orbit (FLIGHT) aboard the International Space Station (ISS); a ground-based control with the same habitat conditions as ISS (Ground Control; GC); and a vivarium control with typical rodent housing conditions (VIV). Pre-flight and post-flight gait measurements were conducted utilizing an optimized and portable gait analysis system (DigiGait, Mouse Specifics, Inc). The total data acquisition time for gait patterns of FLIGHT and control mice was 1.5–5 min/mouse, allowing all 20 mice per group to be assessed in less than an hour. Patterns of longitudinal gait changes were observed in the hind limbs and the forelimbs of the FLIGHT mice after ~35 days in orbit; few differences were observed in gait characteristics within the GC and VIV controls from the initial to the final gait assessment, and between groups. For FLIGHT mice, 12 out of 18 of the evaluated gait characteristics in the hind limbs were significantly changed, including: stride width variability; stride length and variance; stride, swing, and stance duration; paw angle and area at peak stance; and step angle, among others. Gait characteristics that decreased included stride frequency, and others. Moreover, numerous forelimb gait characteristics in the FLIGHT mice were changed at post-flight measures relative to pre-flight. This rapid DigiGait gait measurement tool and customized spaceflight protocol is useful for providing preliminary insight into how spaceflight could affect multiple systems in rodents in which deficits are reflected by altered gait characteristics.

Improved Results in Closed Reduction of Zygomatic Arch Fractures by the Use of Intraoperative Cone-Beam Computed Tomography Imaging

The use of intraoperative imaging could help overcome the insufficiency of closed reduction that can result from the absence of visible feedback to evaluate the accuracy of the reduction in isolated zygomatic arch fractures. The aim of the present study was to evaluate the use of intraoperative 3-dimensional cone-beam computed tomography (CBCT) to improve the accuracy of reduction, by measuring the remaining cortical step and dislocation angle. We also evaluated the effect of CBCT on the need for repeat surgery. We performed a retrospective cohort study of patients who had undergone zygomatic arch reduction surgery from January 2008 to May 2018. The patients were grouped according to the predictor variables into group A (postoperative radiologic follow-up studies) and group B (intraoperative CBCT imaging studies). The primary outcome variables were the remaining cortical step and dislocation angle compared with the ideal virtually mirrored position. These were assessed as measures of reduction accuracy. The secondary variables included age, gender, surgery duration, and fracture type. Statistical analysis was performed using a robust multiple regression analysis. The 45 patients were divided into 2 subgroups with 18 patients in the no intraoperative imaging (control) group and 27 patients in the intraoperative imaging group. Insufficient reduction occurred in 1 patient in the group without intraoperative imaging, leading to repeat surgery. No repeat surgery was necessary in the intraoperative imaging group. The remaining cortical step of the intraoperative imaging group was significantly lower than that of the control group (0.18 vs 2.03mm; P<.001). For the remaining dislocation angle, similar findings were observed but without statistical significance (3.93° vs 7.75°; P=.58). The use of intraoperative CBCT significantly increased the accuracy of the reduction. Furthermore, the need for repeat surgery was not required for any patient in the intraoperative imaging group with CBCT-guided reduction.

Research and Optimization of Vehicle Handling Stability Based on Multi - body Dynamics

Based on multi-body dynamics virtual simulation method, the vehicle simulation model is built and the transient response characteristics of the vehicle are analysed under the steering angle step input. According to the results, the improving method is given. The optimization and stiffness test of tuning bushing are carried out, and the better bushing stiffness is obtained. The vehicle steering transient response performance improvement effect is obvious. This method provides theoretical reference for structural engineers.

Single-crystalline boron-doped diamond superconducting quantum interference devices with regrowth-induced step edge structure

Superconducting quantum interference devices (SQUIDs) are currently used as magnetic flux detectors with ultra-high sensitivity for various applications such as medical diagnostics and magnetic material microstructure analysis. Single-crystalline superconducting boron-doped diamond is an excellent candidate for fabricating high-performance SQUIDs because of its robustness and high transition temperature, critical current density, and critical field. Here, we propose a fabrication process for a single-crystalline boron-doped diamond Josephson junction with regrowth-induced step edge structure and demonstrate the first operation of a single-crystalline boron-doped diamond SQUID above 2 K. We demonstrate that the step angle is a significant parameter for forming the Josephson junction and that the step angle can be controlled by adjusting the microwave plasma-enhanced chemical vapour deposition conditions of the regrowth layer. The fabricated junction exhibits superconductor–weak superconductor–superconductor-type behaviour without hysteresis and a high critical current density of 5800 A/cm2.

Experimentation and FE simulation of single point incremental forming

One of the emerging flexible forming technologies in the sheet metal engineering is the incremental sheet forming, it uses universal tooling that is mostly part independent. Hence this process provide higher flexibility reducing the product development greatly and making it useful for low volume production. Single Point Incremental forming is drawing attention of the researchers & scientist all over the world because of the attractive characteristics. Like: improved formability, elimination of die & conventional press and ease of operation on general purpose Vertical Machining Centre. As this way of creating sheet metal formed products is in development stage, the factors affecting this needs comprehensive investigations.In this paper experimental and numerical investigation of formability of Aluminium 8011 alloy are presented and compared by preparing a conical frustum shape using SPIF process. The complete process is simulated using CATIA manufacturing simulation model to generate the path of Hemispherical end tool tip. Numeric Control (NC) part program is generated with the help of this simulated path to form the sheet into conical frustum shape on CNC mill machine. Four process parameters viz. vertical step depth, feed rate, spindle speed and angle of cone are chosen for the experimental investigations keeping height of the cone and material sheet thickness constant. Temperature, thickness reduction, strain and machining time are selected as a response variable. Optimizations are performed using TAGUCHI and ANOVA while the numerical study of the process is performed through ANSYS workbench software to predict stress, strain, temperature and thickness Results of experiments and numerical study are in close accord.

Research on the Effects of Nonsmooth Surfaces on Backward-facing Step Flow

To achieve the purpose of backward-facing step flow control, a passive control approach, which consists in introducing nonsmooth structures in solid walls, is applied to the upstream of the backward-facing step. Based on STAR CCM+ software, the standard k-ε turbulence model was established to simulate flow characteristics of the right angle step, fillet step and nonsmooth fillet step. The introduction of the nonsmooth surface leads to a significant reduction in recirculation region length (17.5%) and a decrease in downstream wall pressure coefficient. According to the analysis of separation point position and turbulent kinetic energy, the delay of separation point and the enhancement of momentum exchange are the main reasons for the success of flow control. Compared with the right angle step, the delay of flow separation of the fillet step leads to a reduction in step expansion ratio (ER), and the existence of the nonsmooth structure enhances the turbulent kinetic energy at the fluid separation points and the momentum mixing at the downstream of the step, thus reducing the reattachment length and the downstream wall pressure coefficient.

Tests of a Noncontact Piezoelectric Motor Modulated by an Electromagnetic Field.

For improving the service life of piezoelectric motors and the performance of noncontact piezoelectric motors, a novel noncontact piezoelectric motor modulated by the electromagnetic field is proposed. This type of piezoelectric motor uses an electromagnetic field to modulate the reciprocating vibrations of a piezoelectric drive mechanism to form the step motion of the rotor. The working principle and structural design of the piezoelectric motor are described in detail. A prototype motor is manufactured and the test system of output characteristics is established. An experiment of the output characteristics was carried out for exploring the driving scheme under different parameters of the drive signals. The results state that the proposed motor has a rotational speed of 0.038 rad/s, step angle of approximately 1°, output torque of 6 [Formula: see text]mm under the drive voltage of 150 V, frequency of 3 Hz, and modulation voltage of 7 V.

Experimental investigation on single point incremental forming of IS513Cr3 using response surface method

Abstract Sheet metal processing methods have evolved over time with the advancement in their applications and workability. The Incremental sheet forming method under study is an emerging technique of forming the sheet metal in which a single point tool is made to move on the sheet metal as per the predefined program. The motion of the tool with respect to the program produces desires complexities in the sheet metal. The present work focuses on understanding the material behavior of IS513 Cr3 sheet metal when subjected to incremental forming characterized with various parameters like step angle, tool material, feed and spindle speed. Analysis of variance test (ANOVA) is performed to find the effect of step depth and tool diameter on the surface roughness and formability. Finally, optimal comparisons have been made to understand the effectiveness of the process. The effect of forming at high feed rates and tool rotational speeds are studied and results are tabulated. In addition, the response surface method (RSM) analysis is done on the IS513 Cr3 sheet to understand its behavior and property modulations. The hardness of the sheet metal surface in each of the incrementally formed samples are also investigated and the corresponding results are studied.

Detection of wheat height using optimized multi-scan mode of LiDAR during the entire growth stages

Plant height, as an essential phenotypic trait, is widely used in plant breeding, growth monitoring and yield forecasting. As a state-of-the-art technology for tracking diverse structural parameters non-destructively and in situ, terrestrial laser scanning (TLS) can generate three-dimensional geometric information with unprecedented accuracy, particularly with respect to the extraction of plant height. However, few studies have investigated the optimum TLS-derived metrics to retrieve plant height through the entire growth stages. Moreover, in terms of the multi-scan TLS mode, including the number and position of scanning site and scanning angular resolution, have rarely been studied in connection with plant height estimation. In this study, the measurement of plant height as a function of the number of scanning site (2, 4, 6, 8, 10), scanning position (Strategy 1: scanner at the edges of the field; Strategy 2: scanner within the field) and scan step angle (0.04°, 0.06° and 0.08°) were assessed in field tests during the key growth stages of wheat. Specifically, comprehensive analysis was conducted on the effects of scanning number, position and angular resolution on the accuracy and efficiency of estimating wheat height. The results indicated that TLS with H95 can be an effective alternative to monitor short crops like wheat during the entire growth stages, and the height at which wheat can be accurately detected by TLS was as low as 0.18 m, particularly at 0.42–0.9 m with the highest accuracy. Furthermore, the optimum scan step angle was 0.06°, and the optimum scanning position was based on scanning from the four corners of study area (Strategy 1). Increasing the number of scanning site and angular resolution did not always improve accuracy. Overall, our results provide valuable method guidance in effectively acquiring the agricultural parameter for researchers involved in crop breeding and management strategies, and have potential for effective support of LiDAR deployment at the larger field scale to enhance agricultural production.

A minimally invasive endoscope assisted retrosigmoid approach for removal of arachnoid cysts in the internal auditory canal: a step by step description

IntroductionArachnoid cyst in the internal auditory canal is a quite rare pathology but due to its compressive action on the nerves in this district should be surgically removed. Several surgical techniques have been proposed but no surgeons have used the minimally assisted endoscope retrosigmoid approach for its removal. ObjectiveTo investigate the feasibility of using a minimally invasive endoscope assisted retro-sigmoid approach for surgical removal of arachnoid cysts in the internal auditory canal. MethodsMinimally invasive endoscope assisted retrosigmoid approach allows to access to the internal auditory canal through a minimally invasive retrosigmoid approach that combines the use of a microscope and an endoscope. It is performed in six steps: soft tissue step, bone step, dura step, cerebellopontine angle step (performed using an endoscope and a microscope), microscope-endoscope assisted arachnoid cysts removal and closure. We tested minimally invasive endoscope assisted retrosigmoid approach for removal of arachnoid cysts in the internal auditory canal on two human cadaveric heads (specimens) of subjects affected from audio-vestibular disorders and with arachnoid cysts in the internal auditory canal confirmed by magnetic resonance imaging. ResultsThe mass was completely and successfully removed from the two specimens with no damage to the nerves and/or vessels in the surgical area. ConclusionThe results of our study are encouraging and support the feasibility of using minimally invasive endoscope assisted retrosigmoid approach for removal of arachnoid cysts in the internal auditory canal. While further clinical in-vivo studies are needed to confirm the accuracy and safety of using the minimally invasive endoscope assisted retrosigmoid approach for this specific surgery, our group has successfully used the minimally invasive endoscope assisted retrosigmoid approach in the treatment of microvascular compressive syndrome, schwannoma removal and vestibular nerve resection.

Study on the effects of geometry on the initiation characteristics of the oblique detonation wave for hydrogen-air mixture

The Oblique Detonation Wave Engine (ODWE) may act as a hypersonic propulsion system operating at high Mach numbers, which is an important member in the family of Scramjet. Hydrogen is a promising fuel for Scramjet, which provides wider Mach number range and is environmentally friendly. The geometry of the engine greatly affects the performance of the ODWE using hydrogen fuel. This investigation focuses on a novel wedge proposed recently, which may be utilized in scramjet engines. The wedge consists of two sub-wedges and a step. This research focuses on how the geometry of the wedge affects the initiation characteristics of the oblique detonation. Simulations are conducted on basis of Euler equations and a 9-species and 19-reactions mechanism. It is found that a larger leading wedge angle leads to a shorter initiation length. A larger step angle induces a longer initiation length. Few effects are observed on the initiation characteristics for the current range of depth. The streamline surface at the rear of the step weakens the rear shock wave and induces a longer initiation length. The streamline surface at the tip of the step begins to take effect when the initiation position is away from the step. This research provides basis for understanding the performance of the oblique detonation wave under different geometries and provides theoretical basis for scramjet engine design.

Soil roughness retrieval from TerraSar-X data using neural network and fractal method

The purpose of this study is to estimate the surface roughness (rms) using TerraSar-X data in HH polarization. Simulation of data is carried out at a wide range of moisture and roughness using the Integral Equation Model (IEM). The inversion method is based on Multi-Layer Perceptron neural network. Inversion technique is performed in two steps. In the first step, the neural network is trained using synthetic data. The inputs of the first neural network are the backscattering coefficient and incidence angle, and the moisture is the output. In the next step, three neural networks are built based on a prior and without prior information on roughness. The inputs of three neural network are backscattering coefficient, estimated moisture in the first step and incidence angle and the roughness is output. The validation of the proposed methods is carried out based on synthetic and real data. Ground roughness measurements are extracted from Digital Terrain Model (DTM) using the fractal method. The accuracy of moisture from synthetic data is 6.1 vol% without prior information on moisture and roughness. The roughness (rms) accuracy of synthetic datasets is 0. 61 cm without prior information and is 0.31 cm and 0.38 cm for rms lower than 2 cm and rms between 2 and 4 cm, with prior information on roughness. The result's analysis of the simulated data showed that the prior information on roughness strongly improves the accuracy of roughness and moisture estimates. The accuracy of rms estimates for the TerraSar-X image in the HH polarization is about 0.9 cm in the case of no prior information on roughness. The accuracy improves to 0.57 cm for rms lower than 2 cm and 0.54 cm for rms between 2 and 4 cm with prior information on roughness. An overestimation of rms for rms lower than 2 cm and an underestimation of rms for rms higher than 2 cm are observed. The results of the accuracy of the synthetic and real data showed that the X band in HH polarization has a very good potential to estimate the soil roughness.

Long-term exposure to higher temperature increases the thermal sensitivity of grazer metabolism and movement.

Ecological studies of global warming impacts have many constraints. Organisms are often exposed to higher temperatures for short periods of time, probably underestimating their ability to acclimate or adapt relative to slower but real rates of warming. Many studies also focus on a limited number of traits and miss the multifaceted effects that warming may have on organisms, from physiology to behaviour. Organisms exhibit different movement traits, some of which are primarily driven by metabolic processes and others by decision-making, which should influence the extent to which temperature affects them. We collected snails from streams that have been differentially heated by geothermal activity for decades to determine how long-term exposure to different temperatures affected their metabolism and movement. Additionally, we collected snails from a cold stream (5°C) and measured their metabolism and movement at higher temperatures (short-term exposure). We used respirometry to measure metabolic rates and automated in situ image-based tracking to quantify several movement traits from 5 to 21°C. Long-term exposure to higher temperatures resulted in a greater thermal sensitivity of metabolic rate compared to snails exposed for short durations, highlighting the need for caution when conducting acute temperature exposures in global warming research. Average speed, which is largely driven by metabolism, also increased more with temperature for long-term exposure compared to short-term exposure. Movement traits we interpret as more decision-based, such as time spent moving and trajectory shape, were less affected by temperature. Step length increased and step angle decreased at higher temperatures for both long- and short-term exposure, resulting in overall straighter trajectories. The power-law exponent of the step length distributions and fractal dimension of trajectories were independent of temperature, however, suggesting that snails retained the same movement strategy. The observed changes in snail movement at higher temperatures should lead to higher encounter rates and more efficient searching, providing a behavioural mechanism for stronger plant-herbivore interactions in warmer environments. Our research is among the first to show that temperature has contrasting effects on different movement traits, which may be determined by the metabolic contribution to those behaviours.