Journal articles on the topic 'Radian angle measure'
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1
Clayton, David G. "A Trigonometrical Ratio to Replace the Dimensionless Angle in Radians." International Journal of Mechanical Engineering Education 38, no. 2 (April 2010): 132–34. http://dx.doi.org/10.7227/ijmee.38.2.4.
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Equations for use with SI radian units have the option of showing the radian unit or not. When the radian is not shown, identical purely numerical values for angles (θ) are produced in each equation. This is the common procedure. When the radian is shown, not all the θ values can show a radian unit: some must remain as pure numbers. This procedure is used whenever convenient, usually for extra clarity. The article proposes that the constantly numerical values of θ be treated as trigonometrical ratios, currently recognised as the ‘radian measure’ or the ‘circular measure’ (abbreviated: circ) of angles, and replaced by ‘circ θ’. This measure equals the length ratio (subtended arc/radius) for an angle θ at the circle centre. By this means the need for the dimensionless version of ‘angle in radians’ vanishes. In fact even dimensional angles in radians need not be used, because ‘circ θ’ allows any angle units to be used for θ.
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Alyami, Hanan. "A Radian Angle Measure and Light Reflection Activity." Mathematics Teacher: Learning and Teaching PK-12 115, no. 6 (June 2022): 422–31. http://dx.doi.org/10.5951/mtlt.2021.0217.
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During a Desmos activity, students adjust the measures of angles in radians to reposition a laser and a mirror so the beam passes through three stationary targets. The Radian Lasers activity can be extended to simulate project-based learning.
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Eggleton, Patrick J. "Experiencing Radians." Mathematics Teacher 92, no. 6 (September 1999): 468–71. http://dx.doi.org/10.5951/mt.92.6.0468.
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As Einstein stated, most fundamental concepts in science, including mathematics, are essentially simple. Students do not have to memorize and us radian measure without understanding the concept. The simple correspondence between the radial angle and the measure of its arc to the measuring of fractional parts of a wheel in terms of the number of spokes furnishes a concrete representation of the concept of radians.
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Grötschel, Martin, Harald Hanche-Olsen, Helge Holden, and Michael P. Krystek. "On Angular Measures in Axiomatic Euclidean Planar Geometry." Measurement Science Review 22, no. 4 (May 14, 2022): 152–59. http://dx.doi.org/10.2478/msr-2022-0019.
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Abstract We address the issue of angular measure, which is a contested issue for the International System of Units (SI). We provide a mathematically rigorous and axiomatic presentation of angular measure that leads to the traditional way of measuring a plane angle subtended by a circular arc as the length of the arc divided by the radius of the arc, a scalar quantity. We distinguish between the angular magnitude, defined in terms of congruence classes of angles, and the (numerical) angular measure that can be assigned to each congruence class in such a way that, e.g., the right angle has the numerical value π 2 {\pi \over 2} . We argue that angles are intrinsically different from lengths, as there are angles of special significance (such as the right angle, or the straight angle), while there is no distinguished length in Euclidean geometry. This is further underlined by the observation that, while units such as the metre and kilogram have been refined over time due to advances in metrology, no such refinement of the radian is conceivable. It is a mathematically defined unit, set in stone for eternity. We conclude that angular measures are numbers, and the current definition in SI should remain unaltered.
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Giniotis, Vytautas, Mindaugas Rybokas, and Petras Petroškevičius. "INVESTIGATIONS INTO THE ACCURACY OF ANGLE CALIBRATION." Geodesy and cartography 30, no. 3 (August 3, 2012): 65–70. http://dx.doi.org/10.3846/13921541.2004.9636644.
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Technical possibilities to create equipment for the calibration of flat angles are discussed in the article. The angular standard measure, the radian, has not been realised as a standard unit until now. Nevertheless, the unit of angular measure in degrees is used as the geometric measure of length in geodesy, machine engineering and other branches of industry – by multiangular prisms – polygons with an autocollimator, rotary tables, circular scales, etc. It should be noted that these angle measures are calibrated against the upper level measures (etalons) only at the several intervals depending on the number of sides (angles) of the polygon or the other standard measure. The methods of calibration of constant angle value in full circle are used as well. At the same time geodetic instruments, rotary tables of metal cutting tools and instruments, rotary encoders have a great number of discrete values. These values between the calibrated points remain unknown during calibration. The information received during calibration relative to all the information available can be evaluated using information entropy. The equipment of calibration permitting to select significantly more information would be essential for better accuracy assurance of instruments used in machine engineering, geodesy, building structures. Theoretical and technical background for justifying and developing such equipment for angular accuracy calibration is presented here. A modern scientific and technical background validates this concept.
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Alyami, Hanan. "Textbook representations of radian angle measure: The need to build on the quantitative view of angle." School Science and Mathematics 120, no. 1 (January 2020): 15–28. http://dx.doi.org/10.1111/ssm.12380.
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CUI, PENG, and XINGHUA ZHU. "SURGE GENERATION IN RESERVOIRS BY LANDSLIDES TRIGGERED BY THE WENCHUAN EARTHQUAKE." Journal of Earthquake and Tsunami 05, no. 05 (December 2011): 461–74. http://dx.doi.org/10.1142/s1793431111001194.
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Landslides can result in rocks and soil falling into reservoir at high velocity, thereby triggering large surface waves, which may threaten navigation vessels, dam stability, and lives and properties along the shore. This paper presents the results of an experimental study into surges caused by landslides entering reservoirs. First, eight factors — water depth, sliding impact velocity, slide volume, slide width, slide thickness, the mass of the slide blocks, sliding slope, and drop height of the mass center — were chosen as key parameters. Then, these were combined into four dimensionless factors: Froude number for sliding velocity, landslide scale, slide thickness and slide impact angle (radian measure). In addition, based on data from 145 model tests, empirical equations for prediction of the first and second impulsive wave heights were developed through nondimensional multiple linear regression analysis. These equations were applied to landslides triggered by the Wenchuan Earthquake along the shore of Zipingpu Reservoir. The calculated results were found to be in good agreement with field surveys and with calculations by other formulas; the proposed formula is believed preferable in that it incorporates dimension parameters and slope of the sliding surface.
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Johnson, Nick A., Rachel Dias, and Joseph J. Dias. "Scaphoid alignment in dorsally displaced distal radial fracture: a radiographic study." Journal of Hand Surgery (European Volume) 46, no. 6 (January 14, 2021): 600–606. http://dx.doi.org/10.1177/1753193420983696.
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We aimed to establish if fracture reduction will correct scapholunate angle in dorsally displaced distal radial fractures and to identify the relationship with other measures of distal radial position and carpal alignment. Radiographs of 131 patients with a distal radial fracture and of 50 patients with normal radiographs were reviewed. We measured the scapholunate, radiolunate, capitolunate and metacarporadial angles on the lateral views. Linear regression modelling showed that all parameters measured were significantly associated with scapholunate angle on the first radiograph following injury. Scapholunate angle increased following distal radial fracture. Reduction of the fracture improved scapholunate angle, and this was most strongly related to change in dorsal tilt. We conclude that scaphoid flexion is likely to compensate for the dorsal tilt of the lunate as an attempt to counter its dorsal tilt, and to stabilize the wrist to maintain hand function. Level of evidence: IV
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Tong, Junfei, Pengfei Dong, Sachin Kedar, Deepta Ghate, and Linxia Gu. "Three-dimensional shape analysis of peripapillary retinal pigment epithelium-basement membrane layer based on OCT radial images." Nanotechnology Reviews 10, no. 1 (January 1, 2021): 453–64. http://dx.doi.org/10.1515/ntrev-2021-0035.
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Abstract The peripapillary retinal pigment epithelium-basement membrane (ppRPE/BM) layer angle was recently proposed as a potential index for estimating intracranial pressure noninvasively. However, the ppRPE/BM layer angle, measured from the optical coherence tomography (OCT) scans, varied across the radial directions of the optic disc. This made the ppRPE/BM layer angle difficult to be utilized in its full potential. In this study, we developed a mathematical model to quantify the ppRPE/BM layer angles across radial scans in relation to the ppRPE/BM 3D morphology in terms of its 3D angle and scanning tilt angles. Results showed that the variations of the ppRPE/BM layer angle across radial scans were well explained by its 3D angle and scanning tilt angles. The ppRPE/BM layer 3D angle was reversely fitted from the measured ppRPE/BM layer angles across radial directions with application to six eyes from four patients, who underwent medically necessary lumbar puncture. The fitted curve from our mathematical model matched well with the experimental measurements (R 2 > 0.9 in most cases). This further validated our mathematical model. The proposed model in this study has elucidated the variations of ppRPE/BM layer angle across 2D radial scans from the perspective of the ppRPE/BM layer 3D morphology. It is expected that the ppRPE/BM layer 3D angle developed in this study could be further exploited as a new biomarker for the optic disc.
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Anagnost, Susan E., Richard E. Mark, and Robert B. Hanna. "S2 Orientation of Microfibrils in Softwood Tracheids and Hardwood Fibers." IAWA Journal 26, no. 3 (July 15, 2005): 325–38. http://dx.doi.org/10.1163/22941932-02603004.
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In this study the soft-rot method was applied to measuring the variation of microfibril angle (mfa) in loblolly pine, black cherry, sugar maple and canelo. For loblolly pine and black cherry, measurements of the radial wall indicated a gradual decrease in mfa across the earlywood portion of the growth ring, with an abrupt decrease at the latewood zone for pine, and in contrast only a slight decrease in microfibril angle across an annual ring of black cherry. In loblolly pine microfibril angle measurements indicated that the average microfibril angle in radial sections was very similar to the average for tangential sections of the same block. The average microfibril angles in the intermediate plane, or cell corner, were statistically similar to that of the tangential and radial plane, for pine, cherry, and maple. In canelo, microfibril angles in radial sections were significantly larger than in tangential and intermediate sections. In pine latewood the microfibril angles were less than the average mfa for the entire ring, and the earlywood microfibril angles were greater than the average mfa of the entire ring, thus the average mfa for the growth ring did not represent actual measured mfa values.
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Anagnost, Susan E., Richard E. Mark, and Robert B. Hanna. "S2 Orientation of Microfibrils in Softwood Tracheids and Hardwood Fibers." IAWA Journal 26, no. 3 (2005): 325–38. http://dx.doi.org/10.1163/22941932-90000118.
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In this study the soft-rot method was applied to measuring the variation of microfibril angle (mfa) in loblolly pine, black cherry, sugar maple and canelo. For loblolly pine and black cherry, measurements of the radial wall indicated a gradual decrease in mfa across the earlywood portion of the growth ring, with an abrupt decrease at the latewood zone for pine, and in contrast only a slight decrease in microfibril angle across an annual ring of black cherry. In loblolly pine microfibril angle measurements indicated that the average microfibril angle in radial sections was very similar to the average for tangential sections of the same block. The average microfibril angles in the intermediate plane, or cell corner, were statistically similar to that of the tangential and radial plane, for pine, cherry, and maple. In canelo, microfibril angles in radial sections were significantly larger than in tangential and intermediate sections. In pine latewood the microfibril angles were less than the average mfa for the entire ring, and the earlywood microfibril angles were greater than the average mfa of the entire ring, thus the average mfa for the growth ring did not represent actual measured mfa values.
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Rajabi, Benjamin, Oyvind Roed, Kristian Roed, Paal Sandoe Alm-Paulsen, Harald Russwurm, and Vilhjalmur Finsen. "ACCURATE RADIOGRAPHIC MEASUREMENT OF THE DISTAL RADIAL TILT." Hand Surgery 16, no. 03 (January 2011): 259–62. http://dx.doi.org/10.1142/s0218810411005515.
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Both wrists in 189 patients who had been treated for dorsally displaced distal radius fracture were X-rayed with both right angle and 15° tilted lateral views. Two investigators measured the radial tilt. The mean difference in the angles recorded by the two investigators was 2.5° for the tilted and 3.7° for the right angle projections (p = 4.7 × 10-8). The precision of the method was 2.6° for the tilted and 3.5° for right angle projection. The mean angle measured on the tilted views was 3° more dorsal than on the right angle views for wrists with a volar tilt between 10° and 15°, and 0° to 2° for wrists with less volar tilt or dorsal displacement. Lateral projections tilted 15° allow more precise measurements than right angle views. Correction is not necessary when comparing to right angle views, as long as there is displacement in a dorsal direction of the distal fragment.
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Ge, MaoSheng, Pute Wu, Delan Zhu, and Daniel P. Ames. "Comparison between sprinkler irrigation and natural rainfall based on droplet diameter." Spanish Journal of Agricultural Research 14, no. 1 (March 2, 2016): e1201. http://dx.doi.org/10.5424/sjar/2016141-8076.
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<p>An indoor experiment was conducted to analyze the movement characteristics of different sized droplets and their influence on water application rate distribution and kinetic energy distribution. Radial droplets emitted from a Nelson D3000 sprinkler nozzle under 66.3, 84.8, and 103.3 kPa were measured in terms of droplet velocity, landing angle, and droplet kinetic energy and results were compared to natural rainfall characteristics. Results indicate that sprinkler irrigation droplet landing velocity for all sizes of droplets is not related to nozzle pressure and the values of landing velocity are very close to that of natural rainfall. The velocity horizontal component increases with radial distance while the velocity vertical component decreases with radial distance. Additionally, landing angle of all droplet sizes decreases with radial distance. The kinetic energy is decomposed into vertical component and horizontal component due to the oblique angles of droplet impact on the surface soil, and this may aggravate soil erosion. Therefore the actual oblique angle of impact should be considered in actual field conditions and measures should be taken for remediation of soil erosion if necessary.</p>
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Tong, Junfei, Pengfei Dong, Sachin Kedar, Deepta Ghate, and Linxia Gu. "Three-Dimensional Characterization of Peripapillary Retinal Pigment Epithelium-Basement Membrane Layer in Patients following Lumbar Puncture." Applied Sciences 10, no. 5 (February 25, 2020): 1559. http://dx.doi.org/10.3390/app10051559.
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Purpose: To develop and test an innovative semi-automatic method for quantifying the three-dimensional morphology of the peripapillary retinal pigment epithelium-basement membrane (ppRPE/BM) layer, with application to lumbar puncture (LP) patients. Methods: Nineteen patients undergoing LP were recruited. The optic nerve head images of both eyes were acquired in 12 radial directions using optical coherence tomography (OCT) before and after LP. For each OCT image, the ppRPE/BM layer was automatically segmented with manual corrections by independent graders when necessary. The linear regression model of the ppRPE/BM layer was fitted using the least squares approach, and the ppRPE/BM layer angle was measured as the slope of the linear regression line. The Bland–Altman plots and intraclass correlations (ICC) were used to assess the inter-observer reliabilities in measuring the ppRPE/BM layer angle. The repeated measures ANOVA analysis was applied to determine whether the ppRPE/BM layer angle changes following LP varied across the radial directions. Results: The percentages of scans that required manual corrections were 24% and 32% in the right eyes and left eyes, respectively. The Bland–Altman plots and ICC demonstrated excellent inter-observer reliability. The ppRPE/BM layer angle varied significantly across the 12 radial OCT scanning directions both before and after LP. However, the LP-induced changes in the ppRPE/BM layer angle across different radial directions were not statistically significant (p-value > 0.01). Conclusions: The three-dimensional quantifications of the ppRPE/BM layer angles, enabled by the semi-automatic method, provided enhanced information of the optic nerve head structure. For LP patients, the ppRPE/BM layer angle changes following the LP did not vary significantly across various radial directions, indicating that it could be evaluated in any radial direction.
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Luenam, Suriya, Piti Chalongviriyalert, Arkaphat Kosiyatrakul, and Chusak Thanawattano. "ALTERATION OF THE END-PLANE ANGLE IN PRESS-FIT CYLINDRICAL STEM RADIAL HEAD PROSTHESIS: AN IN VITRO STUDY." Hand Surgery 17, no. 01 (January 2012): 19–24. http://dx.doi.org/10.1142/s0218810412500037.
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Purpose: Many studies comparing the morphology of native radial head with the prosthesis have been published. However, there is limited information regarding the postoperative alignment of the articular surface following the radial head replacement. The purpose of this study is to evaluate the alteration of the end-plane angle in the modular radial head prosthesis with a press-fit cementless cylindrical stem. Methods: The study used 36 cadaveric radii. The press-fit size prosthesis with cylindrical stem was inserted into each specimen. The end-plane angles of the radial head before and after prosthetic replacement, were measured in coronal and sagittal planes with a digital inclinometer. The data were analyzed by paired t-test. Results: From paired t-test, there were statistically symmetrical end-plane angles before and after radial head replacement in both coronal and sagittal planes (p-value < 0.01). The mean of radial head end-plane angle alteration in the coronal plane was 3.62° (SD, 2.76°) (range, 0.3°–8.9°). In the sagittal plane, the mean of alteration was 5.85° (SD, 3.56°) degrees (range, 0.3° – 14.2°). Conclusion: The modular radial head prosthesis with cylindrical stem is in vitro able to restore the native end-plane angles of radial heads statistically when used in a press-fit fashion.
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Kalinin, M. I., L. K. Isaev, and F. V. Bulygin. "Dimensions of plane and solid angles and their units in the International System of Units (SI)." Izmeritel`naya Tekhnika, no. 10 (2020): 26–32. http://dx.doi.org/10.32446/0368-1025it.2020-10-26-32.
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The situation that has developed in the International System of Units (SI) as a result of adopting the recommendation of the International Committee of Weights and Measures (CIPM) in 1980, which proposed to consider plane and solid angles as dimensionless derived quantities, is analyzed. It is shown that the basis for such a solution was a misunderstanding of the mathematical formula relating the arc length of a circle with its radius and corresponding central angle, as well as of the expansions of trigonometric functions in series. From the analysis presented in the article, it follows that a plane angle does not depend on any of the SI quantities and should be assigned to the base quantities, and its unit, the radian, should be added to the base SI units. A solid angle, in this case, turns out to be a derived quantity of a plane angle. Its unit, the steradian, is a coherent derived unit equal to the square radian.
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Kwak, D. S., J. Y. Lee, J. H. Im, H. J. Song, and D. Park. "Do volar locking plates fit the volar cortex of the distal radius?" Journal of Hand Surgery (European Volume) 42, no. 3 (November 1, 2016): 266–70. http://dx.doi.org/10.1177/1753193416676704.
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The purpose of this study was to measure the volar cortical angles of the commercially available volar locking plates and evaluate how well they fit the distal radius. We measured the volar cortical angles of the radial and intermediate columns of eight volar locking plates and compared them with the volar cortical angles of 90 cadaver distal radii. The mean radial and intermediate column volar cortical angles of the wider plates were significantly larger than those of narrower plates. The mean radial and intermediate column volar cortical angles were significantly larger in wider radii than narrower radii. The width of the distal radius did not correlate well with the mean volar cortical angles of the radial and intermediate columns. Level of Evidence: IV
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Schoenmarklin, Richard W., and William S. Marras. "Validation of a Hand/Wrist Electromechanical Goniometer." Proceedings of the Human Factors Society Annual Meeting 33, no. 11 (October 1989): 718–22. http://dx.doi.org/10.1177/154193128903301120.
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This paper describes a new hand/wrist electromechanical goniometer that measures wrist angle, velocity, and acceleration in the radial/ulnar and flexion/extension planes. The research objectives of this paper were to validate the angle and motion measures from this goniometer. The results of this research show that the coefficient of variation of the angle measured by the goniometer and the angle measured by a video-based Motion Analysis system was 3%. By smoothing the voltage data three times in software, the goniometer estimated well the velocity and acceleration measures under controlled dynamic conditions. Three smoothing repetitions appear to be the best smoothing regimen for the goniometer because it reduced signal noise while still maintaining the sensitivity of the velocity and acceleration output. Overall, the goniometer is an easy-to-use, accurate system of measuring wrist angle and motion. This goniometer will be used to build a database of wrist motion in industrial tasks.
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Sipos, G. "Secondary Flow and Loss Distribution in a Radial Compressor With Untwisted Backswept Vanes." Journal of Turbomachinery 113, no. 4 (October 1, 1991): 686–95. http://dx.doi.org/10.1115/1.2929135.
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The unshrouded impeller and the vaneless diffuser of a single-stage radial compressor have been investigated at three flow rates. Three-dimensional velocities and pressures were measured at a tip speed of 84 m/s by an L2F-velocimeter, a slanted single hotwire probe, and piezoresistive pressure transducers. The measurements show that upstream of the blading the averaged meridional inlet flow angle is about 54 deg and a periodic variation of the meridional flow angle of about 25 deg occurs near the casing wall. Further, an inlet vortex in the clockwise direction appears and an initial whirl is induced. The specific work of the initial whirl corresponds to approximately 12 percent of the enthalpy losses between inlet pipe and diffuser outlet. In the beginning of the passage, the inlet vortex is suppressed and a solid body vortex in the counterclockwise direction can be observed. At the outlet, a heavy flow deceleration at the blade suction side with subsequent separation can be seen. Increasing the flow rate decreases the wake and causes a more uniform loss distribution in this area. The measured secondary vortex flow and rotary stagnation pressure gradients are compared with test results from impellers with inducer. The incidence of the investigated impeller is greater than that of the impellers with inducer, but the wake-jet outlet flows are very similar. Inlet losses could be reduced by improving incidence angles by matching the blade angles to the inlet flow angles. Smaller blade angles at the shroud would reduce or eliminate separation at the leading edge, and the resulting reduction in low-momentum fluid along the suction surface would help to avoid separation on that surface near the outlet.
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Yadav, Shiv Narayan, Binil Aryal, and Walter Saurer. "Position Angle Distribution of Galaxies in 35 Cluster." Himalayan Physics 4 (December 22, 2013): 1–9. http://dx.doi.org/10.3126/hj.v4i0.9417.
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We worked on POSSII and ESO films and measured the diameters and position angles of 5 688 galaxies in 34 clusters using 25-fold magnification microscope. The position angle distributions of galaxies in the clusters are studied. For this, chi-square, auto-correlation and the Fourier tests are carried out. The preferred position angle distribution of galaxies in the cluster is found to be independent of the mean radial velocity of the cluster. Possible explanations of the result will be discussed.The Himalayan Physics Vol. 4, No. 4, 2013 Page: 1-9 Uploaded date: 12/22/2013
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Martin, Stephen A., Barbara M. Kirby, Gabrielle Kelly, Michael D. Gilchrist, and Joshua Milgram. "Force Distribution in the Canine Proximal Radio-Ulnar Joint on Extension of the Carpal Joint: A Cadaveric Study." Veterinary and Comparative Orthopaedics and Traumatology 33, no. 06 (August 30, 2020): 402–8. http://dx.doi.org/10.1055/s-0040-1715495.
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Abstract Objective The aim of this study was to measure the load on the lateral and medial aspects of the proximal radio-ulnar joint during extension of the carpus. Study Design This was an ex vivo biomechanical study. Sample Population Twenty-two cadaveric Greyhound thoracic limbs were used. Methods Twenty-two paired thoracic limbs were used. The olecranon was attached to a custom jig with the foot resting on a stationary anvil. Load sensors were inserted into the proximal radio-ulnar joint, between the radial head and the lateral coronoid process, and between the radial head and the medial coronoid process. Specimens were tested under compression with measurements taken at 0, 4, 9 and 13.5 mm of axial displacement. Data collected at each point included forces on the specimen and medial and lateral coronoid processes as well as the angle of carpal joint extension. Results A linear mixed effects model relating load on the specimen and carpal joint extension angle had an R-squared value of 0.66, and load at the level of the medial coronoid process and angle of carpal extension had an R-squared value of 0.61. There was a significant difference in the loads measured on the lateral and medial coronoid processes at all angles (p < 0.0001). Conclusion Extension of the carpus results in asymmetric loading of the proximal radio-ulnar joint. Clinical Significance The findings of this study show that loading of the medial coronoid process may be more complex than originally thought and supports the future investigation of novel management and therapeutic options for affected patients.
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Engel, P. A., and D. L. Questad. "Indentation Method to Measure Plating Ductility." Journal of Electronic Packaging 112, no. 3 (September 1, 1990): 272–77. http://dx.doi.org/10.1115/1.2904378.
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The ductility of a plating is an important measure of its durability. In the present paper an indentation test for thin platings is introduced. The test is based on the fact that tensile radial strains arising at the rim of the indentation crater tend to cause cracks in a material of insufficient ductility. By a quantitative knowledge of the radial strain the ductility – i.e., ultimate strain – of the material can be determined. We use a simple geometric analysis which assumes no tangential displacement in the contact area to determine the “average radial strain” across the indentation. In the experiments sharp conical indenters (typically having a 60 degree cone angle with a 0.025 mm (0.001 in.) tip radius) are used, and the plastically deformed crater is checked by electron microscopy (SEM) for cracks. If a crack is detected, its depth is further checked by an attendant X-ray procedure (EDX) for the presence of the underlying substrate material. If a “through-crack” is found, then the ductility of the plating has been exceeded; i.e., the ductility will be equated with the strain value measured for the last indenter loading not involving a crack.
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SINGH, B. P., and AMIT VERMA. "THERMAL EXPANSION IN SINGLE-WALLED CARBON NANOTUBES AT DIFFERENT TEMPERATURES." International Journal of Nanoscience 07, no. 06 (December 2008): 305–13. http://dx.doi.org/10.1142/s0219581x0800547x.
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Energy stored in a bond depends on the bond length and bond angle. We use computer simulation software to measure the bond lengths and bond angles, diameters and other parameters of single-walled carbon nanotubes (SWCNTs), and employ the results to determine thermal expansion of SWCNTs in the radial and axial directions. It is found in this study that at low temperatures and even at room temperature, SWCNTs show negative thermal expansion in both the radial and axial directions (the diameter and length both decrease with the increase in temperature). At high temperatures the expansion becomes positive in the radial and axial directions (the diameter and length both increase with increasing temperature). Thermal expansion in the radial direction does not depend on the tube helicity. SWCNTs of large diameter show higher thermal expansion in the radial direction than that for small diameter tubes up to 700 K, but beyond 700 K the opposite occurs.
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Kim, S., K. Kondo, and T. Akasaka. "Contact Pressure Distribution of Radial Tire in Motion With Camber Angle." Tire Science and Technology 28, no. 1 (January 1, 2000): 2–32. http://dx.doi.org/10.2346/1.2135988.
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Abstract Theoretical and experimental study is conducted on the contact pressure distribution of a radial tire in motion under various camber angles. Tire construction is modeled by a spring bedded elastic ring, consisted of sidewall springs and a composite belt ring. The contact area is assumed to be a trapezoidal shape, varying with camber angles and weighted load. The basic equation in a quasi-static form is derived for the deformation of a running belt with a constant velocity by the aid of Lagrange-Euler transformation. Galerkin's method and stepwise calculation are applied for solving the basic equation and the mechanical boundary condition along both sides of the contact belt part subjected to shearing forces transmitted from the sidewall spring. Experimental results on the contact pressure, measured by pressure sensors embedded in the surface of the drum tester, correspond well with the calculated ones for the test tire under various camber angles, running velocities, and weighted loads. These results indicate that a buckling phenomenon of the contact belt in the widthwise direction occurs due to the effect of camber angle.
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Liu, Qing Min, Ling Zhao, and Wei Feng Dai. "Visual Integrated Measurement on Geometry Parameters of Circular Saw Blade." Advanced Materials Research 97-101 (March 2010): 4346–50. http://dx.doi.org/10.4028/www.scientific.net/amr.97-101.4346.
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Established the circular saw blade visual measurement system and developed geometry parameters measurement software. Calculated the inner and outer circle diameters and the roundness error, the tooth angle and the radial rake angle, the radial direction clearance angle on the basis of image processing. Calibrated the measured part using the standard gauge block. Improved the circle and the line sub-pixel methods. Experiment results showed that the fitting error of improved least–square linear fitting method was quarter of ordinary least–square linear fitting error under small difference of orientation time. The diameters of the inner circle and the outer circle ,the roundness error ,the tooth cusp angle and the radial rake angle, the radial direction clearance angle were respectively 25.204mm, 193.624mm, 0.005mm, 59.999°±0.00695°, 15.004°±0.0104°, 14.997°±0.0137° while taken sub-pixel method.
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Azad, Ali, Jessica M. Intravia, J. Ryan Hill, Hyuma Leland, Venus Vakhshori, Milan Stevanovic, and Alidad Ghiassi. "Carpal Translocation Following Dorsal Bridge Plate Fixation of Distal Radius Fractures: A Cadaveric Study." Journal of Wrist Surgery 08, no. 03 (March 18, 2019): 234–39. http://dx.doi.org/10.1055/s-0039-1683434.
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Background Dorsal bridge plate fixation is an effective technique for stabilization of highly comminuted, complex distal radius fractures. However, it is unknown whether fixation to the second or third metacarpal is optimal. Given dorsal bridge plating spans the radiocarpal joint, it is unclear if the dorsal spanning plate affects carpal position. This study investigates differences in carpal translocation resulting from bridge plate distal fixation to either the second or third metacarpal. Methods Ten paired cadaveric upper extremities without evidence of gross deformity or prior surgery distal to the elbow were evaluated with three-view wrist fluoroscopic images for baseline radiographic measurements. An unstable distal radius fracture model was created via a volar approach using a 1-cm osteotomy. Following fracture creation, a dorsal bridge plate was applied with random to the second metacarpal on one limb, and the third metacarpal on the contralateral limb. Laterality for distal fixation was chosen randomly. Fluoroscopic images were repeated and radial inclination, radial height, radiocarpal angle, volar tilt, ulnar variance, radiolunate angle, radioscaphoid angle, radial rotation index, and carpal translocation were measured. Results Radial inclination, radial height, radiocarpal angle, volar tilt, ulnar variance, radiolunate angle, and radioscaphoid angle were not statistically different before and after fixation, or when comparing the second or third metacarpal fixation. Additionally, there was no difference in Taleisnik's ulnar translocation index, Chamay's ulnar translation index, or McMurtry's carpal translation index based on which metacarpal was used for distal fixation. Conclusions Dorsal bridge plate fixation of distal radius fractures restores preoperative physiologic measures of the radius, ulna, and carpus. Carpal translocation was similar when comparing distal fixation to the second or third metacarpal in distal radius fractures stabilized with a bridge plate. Level of Evidence This is a Level V, therapeutic study.
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Abood, Yasir A., Waad E. Kasid, Omar Abdulrazzaq, and Haider S. Hussein. "Effect of the Blade Pitch on the Performance of Small Wind Turbine Exposed to Wind Stream of Various Angles of Attack." Iraqi Journal of Industrial Research 9, no. 1 (June 14, 2022): 31–38. http://dx.doi.org/10.53523/ijoirvol9i1id151.
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In wind turbines, several parameters can affect the productivity of the turbine, such as wind velocity, rotor area, blade aerodynamic design, and blade pitch. In this paper, the effect of various pitch angles for a small wind turbine was investigated. A system of two metal stands with same height is installed (i.e. on the same axis of streaming), the first stand holds an air blower which imitates the wind with constant air blowing. The other, holds a small wind turbine consists of a DC motor and metal hub (steel bush) with 3-blades with equal radial distance (120°). The pitch angle was adjusted at a certain degree of inclination (10°) in which the turbine stars to rotate, then readings of power and rotational speed were collected. The process then repeated with another 3 different angles (15°, 20°, and 25°). At the end, a fixed pitch angle degree was adjusted, and then the lowest and highest air velocity that affecting the blades rotation were measured.
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Cheng, Qiang, and Huai-Chun Zhou. "The DRESOR Method for a Collimated Irradiation on an Isotropically Scattering Layer." Journal of Heat Transfer 129, no. 5 (July 5, 2006): 634–45. http://dx.doi.org/10.1115/1.2712477.
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Forward and backward Monte Carlo methods may become inefficient when the radiant source is collimated and radiation onto a small, arbitrary spot and onto a small, arbitrary direction cone is desired. In this paper, the DRESOR method was formulated to study the radiative heat transfer process in an isotropically scattering layer exposed to collimated radiation. As the whole spherical solid angle space was uniformly divided into 13,316 discrete solid angles, the intensity at some point in up to such discrete directions was given. The radiation fluxes incident on a detector inside the layer for varying acceptance angles by a step of 2deg were also measured, which agreed well with those in literature. The radiation flux across the top and the bottom boundaries were also provided.
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Kang, K. X., B. He, and S. J. Wang. "Experimental Study on the Breaking Ability of the Cutting Angle of Conical Picks." MATEC Web of Conferences 319 (2020): 04002. http://dx.doi.org/10.1051/matecconf/202031904002.
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This Effects of cutting angle of conical picks affecting on rock breaking capacity was researched to calculate the low construction efficiency of the conical picks at hard rock cutting. Firstly, according to the construction situation of the conical picks, the rotary milling test bench of rock was built. Secondly, the physical and mechanical properties of four kinds of rocks (blue sandstone, red sandstone, limestone, granite.) were measured, and the brittleness index of the four kinds of rocks was calculated. Finally, four kinds of rocks were tested at six cutting angles, respectively. The results of the experiments indicate that the radial force is the largest, the tangential fore is the second, and the lateral force is the smallest in the three-axis of the pick against the four rocks over 50MPa. With the increase of the rock compressive strength, the ratio of radial force to tangential force increases gradually. Therefore, more down-force of machine is needed to improve the impact penetration ability of the pick. Taking milling resistance and specific energy consumption as index, the cutting angle of 63 for the green sandstone and red sandstone, and the cutting angle of 58 for the limestone and granite are helpful to improve the operation efficiency of the whole machine.
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Lou, Zhi-Feng, Xiu-Peng Hao, Yin-Di Cai, Tien-Fu Lu, Xiao-Dong Wang, and Kuang-Chao Fan. "An Embedded Sensor System for Real-Time Detecting 5-DOF Error Motions of Rotary Stages." Sensors 19, no. 13 (June 27, 2019): 2855. http://dx.doi.org/10.3390/s19132855.
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The geometric error motions of rotary stages greatly affect the accuracy of constructed machines such as machine tools, measuring instruments, and robots. In this paper, an embedded sensor system for real-time measurement of two radial and three angular error motions of a rotary stage is proposed, which makes use of a rotary encoder with multiple scanning heads to measure the rotational angle and two radial error motions and a miniature autocollimator to measure two tilt angular errors of the axis of rotation. The assembly errors of the grid disc of the encoder and the mirror for autocollimator are also evaluated and compensated. The developed measuring device can be fixed inside the rotary stage. In the experiments, radial error motions of two points on the axis (h = 5 mm and 60 mm) were measured and calibrated with LVDTs, and the data showed that the radial error motions of the axis were less than 20 μm, and the calibration residual errors were less than 2 μm. When intermittent external forces were applied to the stage, the change of the stage’s error motion could also be monitored accurately.
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Solangi, Aftab Ahmed, Nasrullah ., Amir Jamil, Muhammad Tahir, Jalaludin ., and Imran Abid. "Association between the Angle of the Left Subclavian Artery and Procedural Time for Percutenous Coronary Intervention in Acute Coronary Syndrome Patients." Pakistan Journal of Medical and Health Sciences 16, no. 10 (October 30, 2022): 935–37. http://dx.doi.org/10.53350/pjmhs221610935.
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Background and Aim: Patients with acute coronary syndrome who receive radial access by percutaneous coronary intervention (PCI) are less likely to experience clinical adverse events. The present study aimed to associate the PCI procedural time with left subclavian artery angle in acute coronary syndrome patients. Material and Methods: This retrospective study was carried out on 124 consecutive patients who underwent percutaneous coronary intervention in Punjab Institute of Cardiology, Lahore from June 2021 to June 2022. Prior to study conduction, the ethical committee approved the study protocol. After a CT scan on admission, patients with PCI via an LRA were included in this study. The angle of left subclavian artery was measured on CT scan through coronal view as an indicator for tortuosity and was related with procedural time and clinical variables. SPSS version 26 was used for data analysis. Results: Of the total 124 consecutive patients who underwent PCI, the left radial approach was used in 60 (48.4%) acute coronary syndrome patients. The overall mean age was 64.8±12.6 years. There were 37 (29.8%) females and 87 (70.2%) males. Severe tortuosity patients (left subclavian artery angle <70 degree) had higher incidence of female gender (41.6% vs. 14.2%, p<0.001), older age (73.8±9.87 vs. 59.6±14.2 years, P<0.005), higher subclavian artery calcification (72.6% vs. 32.8%, P=0.001), and hypertension (92.6% vs. 74.8%, P<0.01) than those with angle of left subclavian artery ≥70 degrees. Total procedural time (ρ=-0.29, P=0.003), and sheath cannulation to first balloon time (ρ=-0.48, P<0.001) were negatively associated with left subclavian artery angle. Conclusion: The present study found that Left subclavian artery lower angles are indicators of tortuosity via left radial approach significantly associated with total procedural time and sheath insertion long duration to the first balloon time during percutaneous coronary intervention. Keywords: Acute coronary syndrome, Percutaneous coronary intervention, left radial access
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Gilad, Ronit, Girish M. Fatterpekar, Chirag D. Gandhi, H. Richard Winn, David M. Johnson, Aman B. Patel, Joshua B. Bederson, and Thomas P. Naidich. "Intracranial Tumors: Cisternal Angle as a Measure of Midbrain Compression for Assessing Risk of Postembolization Clinical Deterioration." Radiology 251, no. 3 (June 2009): 892–900. http://dx.doi.org/10.1148/radiol.2513081333.
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Matsumura, Junji, and Brian G. Butterfield. "MICROFIBRIL ANGLES IN THE ROOT WOOD OF PINUS RADIATA AND PINUS NIGRA." IAWA Journal 22, no. 1 (2001): 57–62. http://dx.doi.org/10.1163/22941932-90000268.
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Microfibril angles of the S2 layer and tracheid lengths were measured in the root wood of Pinus nigra, and the root and stem wood of Pinus radiata. Within 10 mm (the first 2–3 growth rings) from the root centre, microfibril angles were large in the wood of both species, ranging from 25° to 40°. Beyond 10 mm (the fourth growth ring and beyond) from the root centre, microfibril angles were small. This pattern of microfibril angle change in root wood differs from those normally found in stems where angles are large until the 10–15th rings. Root wood tracheid length also showed a different pattern in radial direction from that normally observed in stem wood. Tracheids of Pinus radiata root wood were long in the first ring, decreasing to the third ring and then increased to the seventh ring. Beyond the seventh ring tracheid length was stable at around 3 to 3.5 mm. It was noted that microfibril angles were not influenced by tracheid length in root wood.
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Wang, H., R. J. Barthelmie, A. Clifton, and S. C. Pryor. "Wind Measurements from Arc Scans with Doppler Wind Lidar." Journal of Atmospheric and Oceanic Technology 32, no. 11 (November 2015): 2024–40. http://dx.doi.org/10.1175/jtech-d-14-00059.1.
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AbstractDefining optimal scanning geometries for scanning lidars for wind energy applications remains an active field of research. This paper evaluates uncertainties associated with arc scan geometries and presents recommendations regarding optimal configurations in the atmospheric boundary layer. The analysis is based on arc scan data from a Doppler wind lidar with one elevation angle and seven azimuth angles spanning 30° and focuses on an estimation of 10-min mean wind speed and direction. When flow is horizontally uniform, this approach can provide accurate wind measurements required for wind resource assessments in part because of its high resampling rate. Retrieved wind velocities at a single range gate exhibit good correlation to data from a sonic anemometer on a nearby meteorological tower, and vertical profiles of horizontal wind speed, though derived from range gates located on a conical surface, match those measured by mast-mounted cup anemometers. Uncertainties in the retrieved wind velocity are related to high turbulent wind fluctuation and an inhomogeneous horizontal wind field. The radial velocity variance is found to be a robust measure of the uncertainty of the retrieved wind speed because of its relationship to turbulence properties. It is further shown that the standard error of wind speed estimates can be minimized by increasing the azimuthal range beyond 30° and using five to seven azimuth angles.
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Wolbert, Roger S., and Erin R. Moss. "Developing the Concept of a Radian." Mathematics Teacher 111, no. 4 (January 2018): 272–78. http://dx.doi.org/10.5951/mathteacher.111.4.0272.
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Whether you are teaching trigonometry for the first time or you have taught the subject for years, you may be wondering how to get your students more involved in understanding the meaning of a radian. How can you increase student engagement while making radian measures of angles meaningful in a way that provides a solid foundation for future mathematical learning?
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Eng, Kevin, Stephen Gil, and Richard Page. "Diaphyseal Screw Prominence in Distal Radius Volar Plating." Journal of Wrist Surgery 09, no. 03 (March 18, 2020): 214–18. http://dx.doi.org/10.1055/s-0040-1702930.
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Abstract Background Volar plating for distal radius fractures has become common. Screw prominence on the dorsal side from long screws can lead to tendon injury. Methods for detecting screws that penetrate the far cortex involve X-ray or ultrasound. These have focused on the distal row of screws. No studies have addressed screw penetration in the diaphysis. We describe two cases where diaphyseal screws caused symptoms. We then insert screws in the diaphysis of synbones 2 mm longer than measured and determine what angle of pronation or supination was best to detect this on X-ray. Methods Three synbones were plated using Synthes volar plate. The three diaphyseal screws were drilled perpendicular to the plate, and the depth measured. Cortical 2.4-mm screws were inserted, 2 mm longer than measured. The three synbones were then placed in a custom clamp to measure rotation. Lateral X-rays were taken at 0 degree rotation, and 5, 10, and 15 degrees of supination and pronation. The prominence of each screw was measured using the synapse digital ruler. Results For the screws that were placed at a neutral angle (perpendicular to the plate) the maximum visualization of the prominent tips occurred around 0 degree rotation. With screws angled 15 degrees ulna, maximum visualization was between 5 and 10 degrees of pronation. With screws angled 15 degrees radial, maximum visualization was between 5 and 10 degrees of supination. Every 5 degrees of rotation changes the profile of the screw by 0.4 mm. Discussion The diaphysis of the radius becomes approximately trapezoidal distally. Prominent screws that are placed below the “peak” of the trapezoid may appear to be the correct length. Rotating the wrist into pronation or supination to bring the relevant cortex as parallel to the X-ray beam as possible will help to identify if screws are of the correct length. Screws that are prominent in the second compartment may be particularly symptomatic as the tendons here are closely opposed to the bone. We recommend screening for 2 mm diaphyseal screw prominence in neutral, with 10 degrees of pronation and supination.
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Kruyt, Jan W., GertJan F. van Heijst, Douglas L. Altshuler, and David Lentink. "Power reduction and the radial limit of stall delay in revolving wings of different aspect ratio." Journal of The Royal Society Interface 12, no. 105 (April 2015): 20150051. http://dx.doi.org/10.1098/rsif.2015.0051.
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Airplanes and helicopters use high aspect ratio wings to reduce the power required to fly, but must operate at low angle of attack to prevent flow separation and stall. Animals capable of slow sustained flight, such as hummingbirds, have low aspect ratio wings and flap their wings at high angle of attack without stalling. Instead, they generate an attached vortex along the leading edge of the wing that elevates lift. Previous studies have demonstrated that this vortex and high lift can be reproduced by revolving the animal wing at the same angle of attack. How do flapping and revolving animal wings delay stall and reduce power? It has been hypothesized that stall delay derives from having a short radial distance between the shoulder joint and wing tip, measured in chord lengths. This non-dimensional measure of wing length represents the relative magnitude of inertial forces versus rotational accelerations operating in the boundary layer of revolving and flapping wings. Here we show for a suite of aspect ratios, which represent both animal and aircraft wings, that the attachment of the leading edge vortex on a revolving wing is determined by wing aspect ratio, defined with respect to the centre of revolution. At high angle of attack, the vortex remains attached when the local radius is shorter than four chord lengths and separates outboard on higher aspect ratio wings. This radial stall limit explains why revolving high aspect ratio wings (of helicopters) require less power compared with low aspect ratio wings (of hummingbirds) at low angle of attack and vice versa at high angle of attack.
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Zhang, Xing Hong, Fang Yu Peng, Feng Qiu, Rong Yan, and Bin Li. "Prediction of Cutting Force in Trochoidal Milling Based on Radial Depth of Cut." Advanced Materials Research 852 (January 2014): 457–62. http://dx.doi.org/10.4028/www.scientific.net/amr.852.457.
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This paper proposes an approach to predict cutting force of trochoidal milling based on radial depth of cut in order to study the mechanics of trochoidal milling. The tool entry angle and exit angle can be easily achieved to get the cutting force infinitesimals via the radial depth of cut. Through coordinate transformation, a time domain analytical model of cutting force is introduced. Subsequently, a corresponding experiment was done to measure the actual cutting force. Compared with the actual measurement data, the theoretical model is verified to be valid.
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Zaworski, J., J. R. Welty, B. J. Palmer, and M. K. Drost. "Comparison of Experiment With Monte Carlo Simulations on a Reflective Gap Using a Detailed Surface Properties Model." Journal of Heat Transfer 118, no. 2 (May 1, 1996): 388–93. http://dx.doi.org/10.1115/1.2825856.
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The spatial distribution of light through a rectangular gap bounded by highly reflective, diffuse surfaces was measured and compared with the results of Monte Carlo simulations. Incorporating radiant properties for real surfaces into a Monte Carlo code was seen to be a significant problem; a number of techniques for accomplishing this are discussed. Independent results are reported for measured values of the bidirectional reflectance distribution function over incident polar angles from 0 to 90 deg for a semidiffuse surface treatment (Krylon™ flat white spray paint). The inclusion of this information into a Monte Carlo simulation yielded various levels of agreement with experimental results. The poorest agreement occurred when the incident radiation was at a grazing angle with respect to the surface and the reflectance was nearly specular.
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Chen, George Y., Dale Otten, Yvonne Qiongyue Kang, Tanya M. Monro, and David G. Lancaster. "Measuring the Radial Position of Defects within Optical Fibers Using Skew Rays." Journal of Sensors 2017 (2017): 1–5. http://dx.doi.org/10.1155/2017/4879528.
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Defects within optical fibers can cause premature failure in fiber-based systems and must be detected early to avoid performance degradation. Addressing this need can ensure that no defective optical fibers are being used by end users and improve processes to reduce the number of defects during manufacturing. The main challenge to date has been developing a technique that can measure defects along long lengths of fiber, within opaque packaging, and with position information. We demonstrate a simple and novel technique for detecting and radially resolving microscopic defects in packaged/buried fibers using an angle-resolved interrogator that analyzes the transmission of different ray groups. We have measured the accuracy to be as low as ±2 μm, which is sufficient for most fibers that have diameters in the order of ~100 μm.
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Yang, J., S. L. Plee, D. J. Remboski, and J. K. Martin. "Comparison Between Measured Radiance and a Radiation Model in a Spark-Ignition Engine." Journal of Engineering for Gas Turbines and Power 112, no. 3 (July 1, 1990): 331–34. http://dx.doi.org/10.1115/1.2906499.
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Measurements of the radiant emission in the near infrared have been obtained in a spark-ignition engine over a wide range of operating conditions. The system includes an in-cylinder optical sensor and associated detector. Prior work has shown correlations between the measured radiance and pressure quantities such as maximum cylinder pressure, crank angle of maximum pressure, and Indicated Mean Effective Pressure. Here are presented comparisons between the radiant intensity and a simplified model of the radiation emission, which demonstrate that the measured intensity is a function of the mass-burn fraction, mean burned-gas temperature, and the exposed combustion-chamber surface area. Further simplification leads to the conclusion that the time of the maximum rate of change of radiant intensity is the same as for the maximum heat-release rate, leading to the possibility of feedback control of spark timing. In addition, the magnitudes of the maximum rate of change of radiant emission and maximum heat-release rate have a linear relationship over a range of different operating conditions.
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Adamczak, Stanislaw, Paweł Zmarzły, and Krzysztof Stępień. "Assessment of an Influence of Real Values of V-Block Method Parameters on the Method Accuracy of V-Block Waviness Measurement of Rotary Machine Parts." Solid State Phenomena 237 (August 2015): 112–17. http://dx.doi.org/10.4028/www.scientific.net/ssp.237.112.
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The article deals with an application of the V-block method to waviness measurements of rotary mechanical parts. The most popular methods used to measure waviness profile are radial ones. These methods are characterized by a high measurement accuracy and they are usually used to measure waviness profile of small parts under laboratory conditions. Furthermore radial waviness measurements are time-consuming due to centering of measured object on measuring table. Since, large size cylinders are used in many branches of industry, it is necessary to develop another method that allows to determine waviness deviations under industrial conditions. For this purpose the V-block method can be applied. This article presents a design and a principle of operation of a measuring device based on the V-block method. The device was used in the experimental part of the research work to measure waviness profiles. Paper describes also the procedure of identification of real values of V-block method parameters (angles α and β) used in measuring device. For the nominal and real values of angles α and β an experimental V-block method accuracy was calculated. The research result presented in this article indicate that the identification of real values of V-block method parameters increases the method accuracy.
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Entwistle, Kenneth M., Stephen J. Eichhorn, and Namasivayam Navaranjan. "The derivation of the cellulose microfibril angle by small-angle X-ray scattering from structurally characterized softwood cell-wall populations." Journal of Applied Crystallography 38, no. 3 (May 13, 2005): 505–11. http://dx.doi.org/10.1107/s0021889805008319.
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A method is presented for the measurement, using small-angle X-ray scattering (SAXS), of the microfibril angle and the associated standard deviation for the cellulose microfibrils in the S2 layer of the cell walls of softwood specimens. The length and orientation of over 1000 cell walls in the irradiated volume of the specimen are measured using quantitative image analysis. From these data are calculated the azimuthal variation of the scattered intensity. The calculated values are compared with the measured values. The undetermined parameters in the analysis are the microfibril angle (M) and the standard deviation (σΦ) of the intensity distribution arising from the wandering of the fibril orientation about the mean value. The two parameters are varied to give the best fit between the calculated and the measured values. Six separate pairs of values are determined for six different values of the angle of incidence of the X-ray beam relative to the normal to the radial direction in the specimen. The results show good agreement. The azimuthal distribution of scattered intensity for the real cell-wall structure is compared with that calculated for an assembly of rectangular cells with the same ratio of transverse to radial cell-wall lengths. Despite the existence of marked differences in the intensity distributions around the zero azimuth angle, the position of the extreme flanks of the distribution is very close for the real and the rectangular cells. This means that useful values of the microfibril angle can be obtained from the curve for the real cells using the Meylan parameter T derived by drawing tangents to the flanks of the intensity distribution and using M = kT. The value of k is M/(M + 2σΦ). Since both of these parameters are determined in the work now described, k is also determined. It is also demonstrated that for β = 45° (where β is the angle between the plane face of the wood specimens and the radial direction) the peaks in the azimuthal intensity distribution for the real and the rectangular cells coincide. If this peak position is Φ45, then the microfibril angle can be determined from the relation M = tan−1(tanΦ45/cos45°), which is precise for rectangular cells.
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Kagami, S., T. Akasaka, H. Shiobara, and A. Hasegawa. "Analysis of the Contact Deformation of a Radial Tire with Camber Angle." Tire Science and Technology 23, no. 1 (January 1, 1995): 26–51. http://dx.doi.org/10.2346/1.2137494.
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Abstract The contact deformation of a radial tire with a camber angle, has been an important problem closely related to the cornering characteristics of radial tires. The analysis of this problem has been considered to be so difficult mathematically in describing the asymmetric deformation of a radial tire contacting with the roadway, that few papers have been published. In this paper, we present an analytical approach to this problem by using a spring bedded ring model consisting of sidewall spring systems in the radial, the lateral, and the circumferential directions and a spring bed of the tread rubber, together with a ring strip of the composite belt. Analytical solutions for each belt deformation in the contact and the contact-free regions are connected by appropriate boundary conditions at both ends. Galerkin's method is used for solving the additional deflection function defined in the contact region. This function plays an important role in determining the contact pressure distribution. Numerical calculations and experiments are conducted for a radial tire of 175SR14. Good agreement between the predicted and the measured results was obtained for two dimensional contact pressure distribution and the camber thrust characterized by the camber angle.
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Teunis, Teun, Sjoerd Meijer, Jesse Jupiter, and Daniel Rikli. "The correlation between the teardrop angle and anterior lunate facet displacement in plating distal radial fractures." Journal of Hand Surgery (European Volume) 44, no. 5 (January 17, 2019): 462–67. http://dx.doi.org/10.1177/1753193418822470.
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This study aimed to determine the association of teardrop angle and anteroposterior distance with anterior lunate facet displacement and articular congruity before and after anterior plating of distal radial fractures. We included 36 patients with complete intra-articular distal radial fractures with separate anterior lunate facet fragments. On radiographs we determined the teardrop angle and anteroposterior distance. On digital three-dimensional models we measured proximal-distal, anteroposterior and ulnoradial anterior lunate facet displacement, and we outlined the gap surface area. Preoperatively, teardrop angle was highly associated with the extent of anterior lunate facet displacement. Increased anteroposterior distance was mainly associated with articular incongruity after anterior plate fixation. This information may reduce the need of preoperative computed tomography scans in fractures with a normal tear drop angle. This is particularly useful in low-resource settings.
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Guilley, E., M. Loubère, and G. Nepveu. "Identification en forêt de chênes sessiles (Quercus petraea) présentant un angle du fil du bois intrinsèquement faible." Canadian Journal of Forest Research 29, no. 12 (December 15, 1999): 1958–65. http://dx.doi.org/10.1139/x99-141.
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Grain angle on bark (angle between the general direction of bark fissures and the axis of the trunk) was assessed at the four cardinal points at breast height (1.3 m) on 82 standing sessile oaks (Quercus petraea Liebl.). After felling, wood spiral grain was measured at breast height from cambium to pith along two diametrically opposite radii. A mixed-effect model that links the tangent of grain angle to radial position (age and distance from the pith) allows to estimate two individual parameters of grain angle. In the field, nondestructive measurements of grain angle (subcortical spiral grain or spiral grain on bark) on an individual tree combined with information on the tree stand allow to estimate one of the two parameters that describes the change in grain angle for a given radial increment. This parameter is independent of mean ring width, tree age and circumference, and site characteristics; it should allow a more accurate identification and selection of standing trees with low wood spiral grain.
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Moustapha, S. H., G. J. Paron, and J. H. T. Wade. "Secondary Flows in Cascades of Highly Loaded Turbine Blades." Journal of Engineering for Gas Turbines and Power 107, no. 4 (October 1, 1985): 1031–38. http://dx.doi.org/10.1115/1.3239807.
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Experimental measurements of the flow field in a low-speed, large-scale, annular cascade of highly loaded turbine rotor blades are presented. The blade has a turning angle of 128.5 deg, an aspect ratio of 0.88, and a Zweifel coefficient of 1. Detailed cascade tests consisted of inlet and exit flow parameter traverses, blade passage pressure distributions, and flow visualization. The results are presented in the form of contour plots and pitch-averaged radial distributions of losses and flow angles. The measurements are compared with the results obtained for the same blade section tested in a planar cascade. Distribution of the losses and flow angles revealed the presence of two large vortices that occupied a major portion of the trailing edge plane. A large high-loss core was visible in the center of the blade passage and coincided with regions of maximum flow underturning. The measured cascade secondary losses compared well with existing correlations.
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Liu, Yan, Wen Liu, Bing Yang, and Xiao Pai Zhang. "Countermeasures against the Noise of Ring-Plate-Type Cycloid Reducer." Applied Mechanics and Materials 43 (December 2010): 537–40. http://dx.doi.org/10.4028/www.scientific.net/amm.43.537.
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Double crank ring-plate-type cycloid reducer reserves the merits of the traditional cycloid drive, such as more meshing teeth, small angle between radial force and tangential force, hard surface of cycloid gear and pin-tooth. However, the noise of the reducer becomes more and more serious with the increase of speed and load. The noise of the reducer under different work conditions is measured with the SQLabⅡ data acquisition recorder and the collected data are analyzed through Artemis software. Some measures including involute helical cylindrical gear, adding rubber bearing and thickening the cover plate are presented to reduce the noise.
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Xue, Xinbo, Shichao Jin, Feng An, Huaiqing Zhang, Jiangchuan Fan, Markus P. Eichhorn, Chengye Jin, Bangqian Chen, Ling Jiang, and Ting Yun. "Shortwave Radiation Calculation for Forest Plots Using Airborne LiDAR Data and Computer Graphics." Plant Phenomics 2022 (July 18, 2022): 1–21. http://dx.doi.org/10.34133/2022/9856739.
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Forested environments feature a highly complex radiation regime, and solar radiation is hindered from penetrating into the forest by the 3D canopy structure; hence, canopy shortwave radiation varies spatiotemporally, seasonally, and meteorologically, making the radiant flux challenging to both measure and model. Here, we developed a synergetic method using airborne LiDAR data and computer graphics to model the forest canopy and calculate the radiant fluxes of three forest plots (conifer, broadleaf, and mixed). Directional incident solar beams were emitted according to the solar altitude and azimuth angles, and the forest canopy surface was decomposed into triangular elements. A ray tracing algorithm was utilized to simulate the propagation of reflected and transmitted beams within the forest canopy. Our method accurately modeled the solar radiant fluxes and demonstrated good agreement (R2≥0.82) with the plot-scale results of hemispherical photo-based HPEval software and pyranometer measurements. The maximum incident radiant flux appeared in the conifer plot at noon on June 15 due to the largest solar altitude angle (81.21°) and dense clustering of tree crowns; the conifer plot also received the maximum reflected radiant flux (10.91-324.65 kW) due to the higher reflectance of coniferous trees and the better absorption of reflected solar beams. However, the broadleaf plot received more transmitted radiant flux (37.7-226.71 kW) for the trees in the shaded area due to the larger transmittance of broadleaf species. Our method can directly simulate the detailed plot-scale distribution of canopy radiation and is valuable for researching light-dependent biophysiological processes.
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Li, Haifeng, BingQi Li, and Bo Yang. "A Comparative Study of the Cracking Effect of Induced Joints of Various Spatial Formations." Mathematical Problems in Engineering 2019 (January 13, 2019): 1–9. http://dx.doi.org/10.1155/2019/7876503.
Full textAbstract:
The use of induced joints is a common cracking control measure used in the design of roller compacted concrete arch dams. Currently, in some projects in which radial twisted joints were used, during the construction period, some cracks appeared around the induced joints while the joints themselves failed to open. From the fracture mechanics point of view, this problem is related to the variations in the spatial formation of the induced joint planes. In this study, we formulated numerical examples involving square plate and cylindrical arch dam with joints of various planar spatial formations and used the virtual crack-closure technique and the Richard brittle fracture criterion to obtain the equivalent stress intensity factor of the joint plane, and we studied the joint plane stress intensity factor based on the variations in the joint plane formation angle. Based on the reciprocal of the normalized stress intensity factor, we obtained the equivalent strength correction coefficient for induced joints of varying plane angles, referred to in this study as the joint plane formation factor ψα, in order to reflect the influence of varying joint plane formations on the induced joint cracking. Our study results show that as the joint plane angle continuously increases, it is more difficult for the induced joints to open, which implies a gradual increase in the equivalent strength of the joint plane. Therefore, in the actual design of rolled concrete arch dams, the straight transverse joint layout should be used for induced joints. If the use of the radial twisted joint layout is necessary, the joint plane angle should not exceed 10°.