Radius Length Research Articles

Measurement of pavement rutting trajectories on two-lane highway using the 3D line scanning laser system

ABSTRACT Lane departure is one of the important reasons for traffic accidents on a two-lane highway. However, the vehicles’ trajectories obtained by the traditional methods only represent wheel wandering in specifical situations, but do not reflect a regular pattern of lane departure. Pavement rutting trajectories are applied to investigate the regular pattern of lane departure in this paper. A 3D line scanning laser system is utilized to obtain 3D deformed pavement surface images, and rutting trajectories are measured based on the collected data. Inertial Measurement Unit and Distance Measuring Instrument are used to describe lane centreline trajectory of two-lane highways, and curve radius and curve length are measured. A test site on a two-lane highway is chosen as the test bed. Based on the field data, the impacts of undivided opposite lanes, curve turning direction, geometric features, curve radius and curve length on lane departure are analyzed, and the hazardous locations with large lane departures are identified. The significance of this study is that it provides a method to describe a regular pattern of lane departure on two-lane highways, and also benefits transportation agencies in traffic safety analysis and the horizontal alignment design of two-lane highways.

The reduction in laminar burning velocity and Markstein length extrapolation uncertainty for TRF-air mixtures

The laminar burning velocity and Markstein length of TRF (n-heptane, isooctane, and toluene)-air mixtures were investigated at the initial temperature of 400 K and 453 K, initial pressure of 1 bar, and an equivalence ratio range of 0.8–1.5. The effects of extrapolation radius (Rf) and Markstein length (Lb) were discussed on the linear and nonlinear extrapolation models. The results showed that the linear model leads to higher extrapolation result for all equivalence ratios compared with the nonlinear model due to the differences in the third term of Taylor expansion. Finally, the laminar burning velocity and Markstein length uncertainty caused by the extrapolation model can be minimized by adjusting LbRf1 (Rf1 refers to the flame initial extrapolated radius). When the value of LbRf1 was below 0.012, the laminar burning velocity and Markstein length uncertainty can be controlled at < 0.05 and < 0.5, respectively.

Towards the design and optimisation of future compact aero-engines: intake/fancowl trade-off investigation

PurposeRelative to in-service aero-engines, the bypass ratio of future civil architectures may increase further. If traditional design rules are applied to these new configurations and the housing components are scaled, then it is expected that the overall weight, nacelle drag and the effects of aircraft integration will increase. For this reason, the next generation of civil turbofan engines may use compact nacelles to maximise the benefits from the new engine cycles. The purpose of this paper is to present a multi-level design and optimisation process for future civil aero-engines.Design/methodology/approachAn initial set of multi-point, multi-objective optimisations for axisymmetric configurations are carried out to identify the trade-off between intake and fancowl bulk parameters of highlight radius and nacelle length on nacelle drag. Having identified the likely optimal part of the design space, a set of computationally expensive optimisations for three-dimensional non-axisymmetric configurations is performed. The process includes cruise- and windmilling-type operating conditions to ensure aerodynamic robustness of the downselected configurations.FindingsRelative to a conventional aero-engine nacelle, the developed process yielded a compact aero-engine configuration with mid-cruise drag reduction of approximately 1.6% of the nominal standard net thrust.Originality/valueThe multi-point, multi-objective optimisation is carried out with a mixture of regression and classification functions to ensure aerodynamic robustness of the downselected configurations. The developed computational approach enables the optimisation of future civil aero-engine nacelles that target a reduction of the overall fuel consumption.

Effects of magnetic geometry on dynamics of current-convective turbulence in tokamak divertor plasma

The current-convective instability is one of the physical mechanisms that can drive fluctuating transport of plasma in the tokamak divertor. The impact of the tokamak magnetic geometry on spatial and temporal properties of saturated turbulence, driven by the instability, is investigated. The analysis is performed by employing the basic model of the instability [A. A. Stepanenko and S. I. Krasheninnikov, Phys. Plasmas 25, 012305 (2018)] extended to include contributions from the interchange drive. Turbulence simulations are carried out in BOUT++ under DIII-D-like conditions. The dependencies of amplitudes, spatial and frequency spectra of saturated plasma fluctuations on the curvature radius, and connection and shear lengths of magnetic field lines are found. It is demonstrated that taking the finite curvature of the magnetic field into account leads to a large increase in the turbulence amplitude, whereas the shear and connection lengths mainly affect the temporal dynamics of fluctuations and their spatial localization. In all cases shown, the turbulence frequency and wave-number spectra demonstrate better agreement with the experimentally observed ones, compared to the results of previous simulations based on the basic model of the current-convective instability.

Quantitative analysis on self-focusing properties of H-PDLC flexible curved radius gratings.

In general, the shape of traditional holographic grating is fixed and immutable, the period will not change after fabrication, this means that the modulation effect on the light field is unalterable. However, traditional grating cannot satisfy all requirements of current optical systems. In order to increase the versatility of holographic grating, a flexible curved radius grating (FCRG) which consists of holographic polymer-dispersed liquid crystal (H-PDLC) was proposed. The FCRG has an important self-focusing property that it can be adjusted the focal length by changing its own radius of curvature correspondingly. In this paper, we use the scalar diffraction theory to analysis the interference and diffraction processes for FCRG under different conditions, then a relationship equation has been deduced to express quantitatively about FCRG between its radius and focal length. According to the relationship, a tunable holographic element is achieved for the function of mechanically-controlled self-focusing effect. Experiments show that the FCRG has two conjugated focusing effects on the positive first-order and negative first-order, both two effects can achieve focus-adjusted ability by changing their radius of curvature. The FCRG provides a way for the coupler of curved waveguide display system for augmented reality in the future.

Design of Circular Patch Array Microstrip Antenna Using Slot for ISM Band

This paper presents a Microstrip Antenna Analysis for the ISM Band with a circular patch design with a radius of 17 mm at a frequency of 2,400 – 2.484 GHz. The fabricated array antenna has a very compact width and length of 9.5 x 7.5 cm each. Therefore, an increase in bandwidth on the monopole antenna can be applied to the array arrangement. So to get the best antenna design, two optimizations of antenna size changes are carried out during the simulation: optimization of patch radius and slot length. The radius variation is used to shift the frequency range and slot length for impedance matching, as seen from the S11 value of less than -10 dB. From each change, the best results are taken. Experiments get the best antenna simulation results and are then fabricated. From the measurement results on the fabricated antenna, the lowest S11 value is -19.602 dB, and the gain is 3.52 dBi. The slot technique's optimization process has successfully shifted the frequency to approximately 100 MHz and increased the bandwidth by about 5% or 40 MHz.

Clinical Validation of a New Optical Biometer for Myopia Control in a Healthy Pediatric Population.

To assess the clinical validation of the Myah device in a pediatric population by evaluating the repeatability of biometric evaluations and analyzing its agreement with the Myopia Master system. A total of 51 children (51 eyes) were enrolled. Repeated measurements of flat (K1) and steep (K2) corneal radius, white-to-white (WTW) distance and axial length (AL) were performed with the Myah device. The same parameters were obtained from a subgroup (30 eyes) with the Myopia Master for the agreement analysis. The repeatability was assessed using the intrasubject standard deviation (Sw) and the intraclass correlation coefficient (ICC). The agreement was analyzed using the Bland−Altman method and the paired Student t-test. The Sw was 0.018 D, 0.021 D, 0.071 mm and 0.017 mm for K1, K2, WTW and AL, respectively (ICC ≥ 0.971). The mean difference and limits of agreement when comparing instruments were −0.013 (−0.102/0.077) for K1 (p = 0.16), −0.058 (−0.127/0.012) for K2 (p < 0.001), 0.151 (−0.370/0.673) for WTW (p < 0.001) and 0.030 (−0.091/0.151) for AL (p = 0.009). In conclusion, the Myah device provides consistent measurements of corneal radius, WTW distance and AL in a healthy pediatric population, validating their usefulness in clinical practice. These measurements could be used interchangeably with those provided by the Myopia Master device, although with some caution.

Dry shrinkage of Moso bamboo in relation to vascular bundle structure

Abstract Bamboo is susceptible to moisture-induced dimensional instability and cracking. Combining traditional methods with vascular bundle detection, the coordinates and fiber sheath area of each vascular bundle was determined accurately. Based on data fitting, the change in the shape of cross-section was quantified and analyzed based on parameters such as radius, radian, and arc length. The changes in the total area and the areas of different types of fiber sheath, as well as the changes in the arrangement of vascular bundles were studied. The results showed that when the moisture content was reduced from 64% to 0%, the radius of the cross section was increased by 21%, while the radian and arc length decreased by 22% and 6%, respectively. The fibers shrunk by 15%, which was greater than that of the other tissues except bamboo fibers (9%). The gradient distribution of the fiber volume fraction contributed to its asynchronous dry shrinkage. Significant radial and tangential displacements were found in vascular bundles. This work further elucidated the dry shrinkage mechanism of bamboo, and was of great significance for the quantitative analysis of changes in bamboo structure from a combination of micro and macro perspectives.

Experimental Investigation of The Influence of Modifying the Inner Tube Outer Surface on Free Convection in A Concentrated Double Pipe

ABSTRACT Convection across circular concentric gaps between cylinders is crucial in industrial applications, including electronic cooling, heat exchangers, and solar collectors. The effect of longitudinal and annular grooves on the outside surface of the inside tube on natural convective heat transmission in enclosure concentric circular annulus is experimentally investigated in the present work. Twin pairs of circular aluminum cylinders with the same radius ratio, length, and surface area were examined. Each one consists of two concentric circular cylinders. To maintain a steady heat flux, the inside cylinder of each pair has an electrical heater connected. The results indicate that the increases in the Nusselt number of around 25%, 43%, 67%, 123%, 142%, 157%, and 172% are seen for groove depths of 0.05 cm, 0.10 cm, 0.15 cm, 0.20 cm, 0.25 cm, 0.3 cm, 0.35 cm, and 0.4 cm. In addition, increasing the depth of the longitudinal groove raises the Nusselt number by roughly 33%, 51%, 79%, 99%, 136%, 153%, 173%, and 184%. The longitudinal grooves with a depth of 4.0 mm enable a 38% increase in free convection over prior research. An annular groove of 4.0 mm depth increases free convection by 36%. Furthermore, a further advancement over earlier research is attributable to the extensive surface contact area of the inner cylinder made possible by longitudinal or annular grooves.

Density, morphometric characteristics and distribution pattern of Asiatic hard clam (Meretrix meretrix) in Karang Gading estuary, Deli Serdang District, Indonesia

Abstract. Rimelahas WL, Mulya MB, Barus TA. 2022. Density, morphometric characteristics and distribution pattern of Asiatic hard clam (Meretrix meretrix) in Karang Gading estuary, Deli Serdang District, Indonesia. Biodiversitas 23: 5210-5216. Asiatic hard clam (Meretrix meretrix) has a wide distribution, ranging from mangrove forest areas in the Indo-Pacific to mangrove swamp areas in South America. In Indonesia, clam is found on the island of Sumatra, one of which is in the estuary waters of the Karang Gading Wildlife Sanctuary, Deli Serdang District, North Sumatra, Indonesia. In this area, fishermen are often found catching clams. The catch of clams in addition to its own consumption is also widely sold in traditional markets. The existence of clam capture activities carried out continuously can threaten the sustainability of this commodity in nature. This study aims to find out the density, morphometric characteristics, distribution patterns and the relationship of clam density with aquatic physicochemical. Sampling was carried out in July-August 2021 in the estuary waters of Karang Gading Wildlife Sanctuary Deli Serdang District using a purposive sampling method. Sampling was done by using a clam rake with a radius length of 35 cm. At each station, 5 sampling points were determined and 3 dredgings were carried out at each point which is done 2 times with 30-day intervals at 07.00-11.00 WIB. The results concluded that the highest density of clam is found in station I with a value of 3896 ind/m2, the pattern of growth of the clam at each station is negative allometric, the pattern of the group and uniform clam distribution, and the correlation of physical and chemical factors of the waters with the density of the clam shows that phosphate has a very strong correlation to the density of the clam, while the temperature correlates moderately with the density of the clam.

Optimization of tracker configuration for the CEPC

We investigate the tracker configuration optimization for the Circular Electron Position Collider (CEPC), a proposed Higgs and Z factory. Fixing the construction cost comparable to that of the baseline detector design and considering the benchmark channels (Z ⟶ ff̅, WW fusion with H ⟶ ff̅, ZH ⟶ ννff̅, and tt̅ ⟶ bb̅μνμud) of various operating modes of the CEPC, we obtain the optimal tracker radius that provides the best average resolution of the track momentum or jet energy. The optimal tracker radii for track momentum resolution range from 1.59 m to 1.73 m and for jet energy resolution from 1.82 m to 1.97 m, depending on the benchmark channels. Compared to the jets, the tracks prefer a smaller radius and a longer length because the track momentum resolution degrades more significantly than jet energy resolution in the forward region. The benchmark channel for Z-pole prefers a smaller radius and longer length compared to other benchmark channels because the final state particles at the Z-pole have a more forward distribution. We also analyze the scaling behavior of the optimal tracker configuration at floating construction cost and observe a weak dependence.

Radial and ulnar medullary canal diameter in children: Anatomical limitations of elastic stable intramedullary nailing.

Surgery is inevitable for children who cannot achieve the ideal reduction in forearm fractures. The biggest limitation of the elastic stable intramedullary nail (ESIN) fixation method is the diameter of the medullary canal. This study aimed to measure the medullary canal diameters of the radius and ulna at different ages in children. The forearm radiographs of 540 children were retrospectively reviewed. All background characteristics, including weight, sex, maturity of the radius and ulna, and length of the radius and ulna, were measured and recorded. Children with radius and ulnar diameters shorter than 2 mm were analyzed by statistical regression analysis by SPSS software. When we set 2 mm as the minimum medullary canal diameter, our results showed that patients aged 3-12 years had radius and ulnar diameters under this limit. The regression analysis of risk factors with the 2 mm diameter limitation had significant differences based on age (P = 0.006) and sex (P = 0.033). There was no significant difference between patients based on weight (P = 0.056), ulnar length (P = 0.946), radius length (P = 0.503), radius maturity (P = 0.655), or ulnar maturity (P = 0.774). The average medullary canal diameter remained constant until 12 years of age. However, the average diameter length did not increase significantly after the age of 12 years. The incidence of medullary canal diameter shorter than 2 mm was correlated with age and sex. Our results suggest that surgeons should pay attention to the medullary diameter of the anteroposterior and lateral radiographs to determine the ESIN diameter.

Physics-Based Performance Optimization of Fiber-Optic Interferometric Hydrophone With Push–Pull Mandrel Structure

The influence of the parameters of the elastic mandrel on the performance of fiber-optic interferometric hydrophone with a push–pull structure comprised of two concentric cylindrical shells is investigated through systematic solid mechanical analysis. The structural and material parameters considered include Young’s modulus, Poisson ratio, the thickness, length, and outer radius of the elastic tube. The result shows that a higher sensitivity of the push–pull fiber-optic hydrophone can be obtained with a lower Young’s modulus and Poisson ratio, and a thinner wall, larger radius, and longer length of the elastic tube, accompanied by a lower fundamental resonant frequency. Therefore, obtaining an optimal performance of the push–pull fiber-optic hydrophone often entails a tradeoff between material properties and geometric parameters. A family of prototypical fiber-optic hydrophones with different structural parameters are fabricated and examined experimentally, corroborating the results of solid mechanical [finite-element method (FEM)] analysis, among which the push–pull fiber-optic hydrophone with the optimal parameters has demonstrated notably improved acoustic frequency response characteristics and a reduced minimum detectable pressure (MDP).

TOPOGRAPHY OF NUTRIENT FORAMINA OF ADULT DRY RADII IN SOUTH INDIAN POPULATION WITH A NOTE ON ITS SURGICAL RELEVANCE

Objective: The objective of this study was to study the average length of adult dry radii in south Indian population, distribution of nutrient foramina, and foraminal index. Methods: This study was conducted using 200 dry, adult radii, obtained from the department of Anatomy at our institute. Fully formed radii of both sides and genders were included in the study. Length of each bone, distribution, and direction of nutrient foramina on diaphysis were studied with the help of a Vernier caliper. Later, foramen index was estimated for all bones using Hughes formula. The data were tabulated and analyzed statistically. Results: Average length of radii in the study was 23.37±1.65 cm. All radii had their nutrient foramina, directed proximally. About 2% of the study sample had double nutrient foramina. Increased number of foramina had no effect on length of bone. As many as, 57.5% of radii had nutrient foramen on the anterior surface of shaft. Mean foramen index was 34.24±4.75. Conclusion: This study provides population-specific data regarding length of adult radii and topography of nutrient foramina of adult radii. An attempt was made to acknowledge its relevance while harvesting a vascular graft.

Reliability-Based Robust Design Optimization for Maximizing the Output Torque of Brushless Direct Current (BLDC) Motors Considering Manufacturing Uncertainty

In recent years, the deterministic design optimization method has been widely used to improve the output performance of brushless direct current (BLDC) motors. However, it does not contribute to reducing the failure rate and performance variation of products because it cannot determine the manufacturing uncertainty. In this study, we proposed reliability-based robust design optimization to improve the output torque of a BLDC motor while reducing the failure rate and performance variation. We calculated the output torque and vibration response of the BLDC motor using the electromagnetic–structural coupled analysis. We selected the tooth thickness, slot opening width, slot radius, slot depth, tooth width, magnet thickness, and magnet length as the design variables related to the shape of the stator and rotor that affect the output torque. We considered the distribution of design variables with manufacturing tolerances. We performed a reliability analysis of the BLDC motor considering the distribution of design variables with manufacturing tolerances. Using the reliability analysis results, we performed reliability-based robust design optimization (RBRDO) to maximize the output torque; consequently, the output torque increased by 8.8% compared to the initial BLDC motor, the standard deviation in output performance decreased by 46.9% with improved robustness, and the failure rate decreased by 99.2% with enhanced reliability. The proposed reliability-based robust design optimization is considered to be useful in the actual product design field because it can evaluate both the reliability and robustness of the product and improve its performance in the design stage.

An Annular Fresnel Zone Plate without Central Spots Fabricated by Femtosecond Laser Direct Writing.

In recent years, micro-annular beams have been widely used, which has expanded the possibilities for laser processing. However, the current method of generating an annular beam still has shortcomings, such as spot energy at the center of the produced beam. In this study, a Fresnel zone plate with an annular structure was machined using a femtosecond laser. After focusing, an annular laser beam without a spot in the center was obtained, and the radius and focal length of the annular beam could be easily adjusted. In addition, two annular Fresnel zone plates were concentrically connected to obtain a concentric double-ring beam in the same focal plane. The simulation and experimental results were consistent, providing effective potential for applications related to nontraditionally shaped laser beams.

Performance Optimization of Helicopter Rotor in Hover Based on CFD Simulation

An optimization method of helicopter rotor hovering performance is proposed, which is mainly carried out by means of CFD simulation. This method can be used to obtain the rotation speed of any blade model under the designed hovering tension through several iterations, and then, the tension, torque, power, and power load of the rotor under the rotation speed can be obtained. By comparing different blade pitch, radius, twist, and chord length, the blade parameters at the highest power load can be selected. A series of new rotor models are obtained by changing the model parameters on the basis of C-T rotor. NASA has carried out a lot of experiments on the C-T rotor model and published detailed experimental reports. The transient simulation is carried out by the embedded grid method.

Characteristics of the length of the radius and ulna in children.

ObjectivesCongenital malformation, trauma, tumor, or metabolic disease can cause length deformity of the radius or ulna, affecting the appearance and function of the forearm. Osteotomy and lengthening with external fixation can obviously improve the length of the radius and ulna (LRU). However, the extent of lengthening required is still unclear. This study analyzed the LRU in children, to provide suggested standards for various orthopedic treatments.MethodsNormal LRUs were measured on X-ray images in children who came to hospital for emergency treatment, with measurements including anterior–posterior (AP) radiographs, lateral (LAT) radiographs, full LRU (total length), and LRU without the epiphysis (short length). Any cases of fracture or deformity affecting measurement were excluded. Three hundred twenty-six cases were divided into 16 groups according to age from 1 year old to 16 years old.ResultsThe earliest epiphyseal plate and ossification center were observed in the distal part of the radius at 1 year old, and in the proximal part at 3 years old in both boys and girls. In the ulna, at the distal end it was 6 years old in girls and 7 years old in boys, while in the proximal part ossification was observed at 9 years old in both boys and girls. The proximal epiphyseal plate of the ulna began to close on X-ray images at 12 years old in girls and 13 years in boys. LRU increased with age, and there was a strong positive correlation and consistent ratio between radius, ulna and age. In short length, the ratio of the length of radius to ulna (RLRU) ranged from 0.8941 to 0.9251 AP, from 0.8936 to 0.9375 LAT. In total length, RLRU ranged from 0.9286 to 0.9508 AP, and 0.9579 to 0.9698 LAT.ConclusionsThe length and epiphyseal ossification of the radius and ulna are associated with age. RLRU is also limited to a certain range and tends to remain stable with age. These characteristics have clinical significance for deformity correction of the forearm.

Improvement to the fictitious pile method for pile-soil interaction problems

Dynamic pile-soil interaction analysis is often a key task in many civil engineering problems and several methods have been developed and applied. To many researchers, the fictitious pile method is a good candidate because of its high computational efficiency compared with the three-dimensional finite element method (FEM) and boundary element method (BEM). However, due to the assumptions made in the method, application of the method to dynamic pile-soil interaction at sufficiently high frequency may be problematic. A study on this issue is performed in this paper by comparing with FEM. It is found that the assumption that the vertical load (termed the patch load) applied by the fictitious pile to the ground is uniformly distributed on the cross-section is an important factor invalidating the method at high frequencies. Upon this founding, the original fictitious pile method is then improved by replacing the uniformly distributed patch load with a series of ring loads which make the vertical displacements at the intermediate radii of the ring loads identical. A set of linear algebraic equations are established to determine the ring loads. Results from both the improved and original fictitious pile methods are compared with those from FEM as benchmark. The comparisons show that the improved fictitious pile method has a much better accuracy (or for a given accuracy, works to higher frequencies) than the original one but the calculation efficiency remains similar. Although for the cases studied in this paper the improved fictitious pile method is much more accurate than the original one, the effectiveness of former may be still unsatisfactory for other cases. Therefore, the effect of parameters, including soil Young's modulus, pile radius and pile length, on the accuracy of the fictitious pile method is also investigated. It turns out that the pile radius and length have adverse effects on the accuracy of the fictitious pile method while stiffer soil makes the method work better. Based on the parameters of the pile and soil, a critical frequency is derived below which the fictitious pile method can be well applied.

The unusual rheological behaviors of poly(acrylamide-co-acrylonitrile)s with UCST features in aqueous solutions

The polymer with the upper critical solution temperature (UCST) in aqueous solution exhibits temperature sensitivity, whose solvation is more sensitive to temperature than that of ordinary polymer in aqueous solution. However, the rheological behavior of UCST-type polymer in aqueous solution with temperature has not been definitively concluded. In this work, the rheological behaviors of poly(acrylamide-co-acrylonitrile) with UCST features in dilute and semi-dilute aqueous solutions at different temperatures were investigated. Our results showed that the viscosities of both the dilute and semi-dilute aqueous solutions increase when temperature rises. To understand this unusual observation of rheological behavior, related dynamic and thermodynamic properties were studied. The intrinsic viscosity ([η]), viscometric radius (Rη), hydrodynamic size (Rh), friction coefficient (ζ), relaxation time(τ) and correlation length(▪) of the solution were quantitatively investigated at different temperatures. Based on experimental data, the theta temperature was determined, and the change rate of excluded volume with temperature was also obtained. The interaction parameter χ and intermolecular interactions of polymer were analyzed at different temperatures. The unusual rheological behavior of UCST-type polymer in aqueous solution is analyzed according to classical polymer physics based upon our experimental observations. We envisage that this work will provide an insight and benefit for the design of thermoviscosifying UCST-type polymers which is urgently needed in both petroleum and chemical industries.