Journal articles: 'Reducing curvature'

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Bandyopadhyay, P. R. "Review—Mean Flow in Turbulent Boundary Layers Disturbed to Alter Skin Friction." Journal of Fluids Engineering 108, no. 2 (June 1, 1986): 127–40. http://dx.doi.org/10.1115/1.3242552.

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Recent developments in methods of reducing drag in turbulent boundary layers have been briefly reviewed. The behavior of the mean flow in several drag reducing boundary-layer flows of current interest, viz., those over longitudinal surface riblets, outer-layer devices (OLD’s), and longitudinal convex surface curvature, has been examined. The boundary layer on a surface with longitudinal concave curvature has been studied to complement the results of convex curvature. The riblets alter the flow in their vicinity only and cause no drag penalty. However, the OLD’s disturb the entire boundary layer, and it is the slow downstream (≃150 δ0) relaxation back to the equilibrium state that produces a region of lower skin friction; a net drag reduction results when the wall-drag reduction exceeds the drag penalty due to the device. The net drag reduction achieved by the riblets and OLD’s remains a modest 10 percent compared with the more spectacular levels reached by polymer addition and microbubble injection in water. Over mild convex curvatures, the outer-boundary-layer response is a function of the curvature ratio (δ0/R), and the relaxation rate after a length of convex curvature is a function of the curved length ratio (Δs0/δi). Boundary layers exhibit an asymmetric response to streamwise surface curvatures; the response is slower to a concave curvature than to a convex. Detailed turbulence and accurate wall shear stress measurements in the altered boundary layers are needed to understand the drag-reducing mechanisms involved.

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Etemadi, Ehsan, Abbas Naseri, and Mohsen Valinezhad. "Novel U-bending designed setups for investigating the spring-back/spring-go of two-layer aluminum/copper sheets through experimental tests and finite element simulations." Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications 234, no. 8 (June 5, 2020): 1142–53. http://dx.doi.org/10.1177/1464420720930251.

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This paper presents novel U-bending setups in order to investigate the effects of the curvatures created on the punch, die, or both on the spring-back/spring-go of the two-layer aluminum/copper sheets. Comparison of the new U-bending setups with the regular ones showed that the curvatures had important roles in reducing the spring-back/spring-go in the U-bending process. The results further indicated the good agreement between spring-back/spring-go and finite element simulations. Moreover, through finite element simulations, the effects of three effective parameters on reducing the spring-back/spring-go, including the curvature radius ( r) of the punch, the distance between curvature center and the fillet center ( d) in the punch, and the curvature radius at the end of the die ( R) were investigated. In achieving the desired state (90°), the results showed that the distance of curvature center from the fillet center ( d) was a more important parameter compared with the curvature radius at the end of the punch ( r) and the curvature radius at the end of the die ( R). This paper also focuses on the thicknesses of copper and aluminum as well as the stacking sequence of layers. Concerning the thicknesses of the implemented copper and aluminum change, the minimum angle of the spring-back/spring-go relative to the desired state was 75% Al/25% Cu thickness. Furthermore, the spring-back of aluminum/copper was lower than the copper/aluminum layer sheet. The effects of both thickness changing and stacking sequence of aluminum/copper layers on the spring-back/spring-go amounts of different sheets were due to the relocation of the neutral axis.

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Syahrullail, Samion, Md Razak Daud, Norzahir Sapawe, and Azli Yahya. "The Effect of Pits on the Curvature Cup: For Reducing Friction in Soft on Hard Sliding Contact." Applied Mechanics and Materials 819 (January 2016): 489–94. http://dx.doi.org/10.4028/www.scientific.net/amm.819.489.

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The purpose of this feasibility study is to elucidate the effect of surface modification on the curvature cup made of Acrylonitrile Butadiene Styrene (ABS) against metal ball bearing was investigated. In the tribology soft on hard (SoH), the pits embedded on the curvature cup have shown potential for reducing friction in curvature structure. A modified four ball machine as a hard-on-soft screening machine has been used to evaluate the friction on the curvature cup sample with an inner diameter of 12.8 mm. This study revealed that the treated curvature cup with pit in lubricated of palm oil optimizes the rate of frictional and allows for a stable of soft on hard sliding contact.

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Lovrić, Miroslav. "Curvature Pinching Based on Integral Norms of the Curvature." Canadian Journal of Mathematics 45, no. 3 (June 1, 1993): 599–611. http://dx.doi.org/10.4153/cjm-1993-031-1.

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AbstractA compact Riemannian manifold (M, g) of dimension 3 or higher admits a metric of constant (positive or negative) sectional curvature if the following conditions hold: the diameter is bounded from above, the part of the Ricci curvature which lies below some fixed negative number is bounded in LP norm for p > n/2, and the metric is almost spherical or almost hyperbolic in the LP sense. The idea of the proof is to obtain stronger (i.e. L∞) pinching by deforming the initial metric using the Ricci flow, thus reducing the problem to the theorems of Gromov in the case rg < 0 and of Grove, Karcher and Ruh in the case rg > 0. The reduced curvature tensor changes along the flow according to the heat equation, which implies a weak nonlinear parabolic inequality for its norm. The iteration method of De Giorgi, Nash and Moser is applied to obtain the estimate for the maximum norm of the reduced curvature tensor. The crucial step in the iteration consists of controlling the Sobolev constant of the appropriate imbedding (which also changes along the flow, but behaves well) by the isoperimetric constant, which, in turn, can be bounded in terms independent of the particular manifold.

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Yao, Jianjun, Fengshen Li, Junhua Chen, Zheng Yuan, and Wangeng Mai. "Parameter Analysis of Savonius Hydraulic Turbine Considering the Effect of Reducing Flow Velocity." Energies 13, no. 1 (December 19, 2019): 24. http://dx.doi.org/10.3390/en13010024.

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The Savonius-type hydraulic turbine, mainly known for its good self-starting properties and simple structure, not only has energy capturing characteristics but also has a certain effect on flow velocity reduction. Aside from ensuring energy capture efficiency, studying the effects of parameters on the flow velocity reduction capacity is of great significance for the protection of mariculture, as it can reduce the damage to cages and fishes. In this study, a computational fluid dynamics method was carried out to investigate the hydrodynamic characteristics and variations in the wake of a turbine. The accuracy of the simulation results was verified by experimental comparison. Firstly, the velocity contours and vectors were studied in detail to reveal the mechanism of the flow velocity reduction effect. Secondly, the velocity attenuation coefficient and relative attenuation length were formulated by the variation rule of the velocity field to evaluate the turbine reduction strength and range. Finally, the power coefficient was considered to predict the performance of a turbine under different tip speed ratios, overlap ratios, blade curvatures, and blade numbers. The results showed that the turbine had an obvious flow velocity reduction effect in the rear “sword”-shaped area, where the velocity field distribution had a certain regularity. In addition, by comprehensively comparing the simulation data, it was found that the respective effect trend of tip speed ratio, blade number, overlap ratio, and curvature on the turbine’s energy capture and flow velocity reduction characteristics was basically the same. Considering the effect of reducing flow velocity, a two-bladed turbine with a blade curvature of 0.8 and an overlap ratio of 0.15 is the optimal configuration.

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Naseath, G. B., and W. E. Red. "Reducing Curvature by Deviating CAM Tool Paths within a Tolerance Band." Computer-Aided Design and Applications 5, no. 6 (January 2008): 921–31. http://dx.doi.org/10.3722/cadaps.2008.921-931.

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Wu, Jin-mei, Xiao-dong Ling, Ya-wei Hou, Yu-xin Zhang, and Yi Wang. "Study on the Curvature Reducing Method of Non-linear Regression Model." MATEC Web of Conferences 63 (2016): 05033. http://dx.doi.org/10.1051/matecconf/20166305033.

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López, J., and J. Hernández. "On reducing interface curvature computation errors in the height function technique." Journal of Computational Physics 229, no. 13 (July 2010): 4855–68. http://dx.doi.org/10.1016/j.jcp.2010.03.032.

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Naesgaard, Ernest. "Lateral load tests to examine large-strain (seismic) behaviour of piles." Canadian Geotechnical Journal 29, no. 2 (April 1, 1992): 245–52. http://dx.doi.org/10.1139/t92-028.

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Three different 406 mm diameter piles were tested with lateral, vertical, and moment loadings. The purpose of the full-scale field tests was to assess the ability of the piles to withstand large lateral deformations that may be caused by earthquake-induced soil liquefaction. Two concrete shaft piles were tested to failure with lateral displacements at the pile top of up to 300 and 650 mm and pile curvatures of up to 0.16 and 0.35 rad/m, respectively. The third pile, a concrete-filled steel pipe shaft pile, reached a maximum lateral displacement at the pile top of 550 mm and a curvature of 0.08 rad/m without failure or significant distress. It is concluded that stronger piles that push through the soil may tolerate larger lateral displacements than weaker piles and that reducing the spiral reinforcing pitch from 150to 100 mm on concrete piles greatly increases the pile ductility. Key words : lateral load test, piles, reinforced concrete, concrete-filled pipe, seismic, liquefaction, pile curvature.

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Varna, Janis, Magnus Persson, and Abdelghani Hajlane. "Microdamage, Viscoelasticity and Viscoplasticity as Main Phenomena in Thermal Stress Relaxation in Laminated Composites." Key Engineering Materials 713 (September 2016): 99–102. http://dx.doi.org/10.4028/www.scientific.net/kem.713.99.

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Microdamage, viscoplastic and viscoelastic strain development in 90-layers of cross-ply laminates subjected to tensile loading is studied on unsymmetrical GF/EP laminates measuring the thermal curvature change. All three phenomena partially compensate for the effect of the thermal mismatch reducing the residual stress (specimen curvature). The viscoplastic strain contribution to curvature change is the largest whereas the effect of transient viscoelasticity is the smallest. Damage is included in the analysis through its effect on the effective transverse modulus of the 90-layer.

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Webster, Thomas J. "Reducing Infections Using Nanotechnology." MRS Proceedings 1621 (2014): 25–32. http://dx.doi.org/10.1557/opl.2014.5.

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ABSTRACTVentilator associated pneumonia (VAP) is a serious and costly clinical problem. Specifically, receiving mechanical ventilation for over 24 hours increases the risk of VAP and is associated with high morbidity, mortality and medical costs. Cost effective endotracheal tubes (ETTs) that are resistant to bacterial infection could help prevent this problem. The objective of this study was to determine differences in the growth ofStaphylococcus aureus(S. aureus) on nanomodified and unmodified polyvinyl chloride (PVC) ETTs under dynamic airway conditions. PVC ETTs were modified to have nanometer surface features by soaking them inRhizopus arrhisus,a fungal lipase. Twenty-four hour experiments (supported by computational models) showed that air flow conditions within the ETT influenced both the location and concentration of bacterial growth on the ETTs especially within areas of tube curvature. More importantly, experiments revealed a 1.5 log reduction in the total number ofS. aureuson the novel nanomodified ETTs compared to the conventional ETTs after 24 hours of air flow. This dynamic study showed that lipase etching can create nano-rough surface features on PVC ETTs that suppressS. aureusgrowth and, thus, may provide clinicians with an effective and inexpensive tool to combat VAP.

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Salgo, Ivan S., Joseph H. Gorman, Robert C. Gorman, Benjamin M. Jackson, Frank W. Bowen, Theodore Plappert, Martin G. St John Sutton, and L. Henry Edmunds. "Effect of Annular Shape on Leaflet Curvature in Reducing Mitral Leaflet Stress." Circulation 106, no. 6 (August 6, 2002): 711–17. http://dx.doi.org/10.1161/01.cir.0000025426.39426.83.

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Yu, Haili, Xiaotian Li, Jiwei Zhu, Hongzhu Yu, Xiangdong Qi, and Shulong Feng. "Reducing the line curvature error of mechanically ruled gratings by interferometric control." Applied Physics B 117, no. 1 (April 22, 2014): 279–86. http://dx.doi.org/10.1007/s00340-014-5832-z.

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Li, Simon SW, and Daniel HK Chow. "Effects of asymmetric loading on lateral spinal curvature in young adults with scoliosis: A preliminary study." Prosthetics and Orthotics International 42, no. 5 (February 26, 2018): 554–62. http://dx.doi.org/10.1177/0309364618757784.

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Background: Usual guidelines recommend symmetric load carriage over asymmetric load carriage. Whether this recommendation is valid for subjects with asymmetric body alignment, such as those with scoliosis, remains unclear. Scoliosis is both a subject-dependent and time-variant condition. Interventions are generally employed to prevent the abnormal spinal curvature from progressing. Objectives: To investigate the effects of an asymmetric load carriage on lateral spinal deformity in participant with scoliosis. Study design: Repeated measure and single-case experimental designs Methods: Photogrammetry was employed to measure the scoliotic curvature changes in thoracic and lumbar regions without a load (0%) and with a single-strap cross-chest bag loaded at 2.5%, 5%, 7.5%, 10% and 12.5% of body weight. Statistical tests and programming models were adopted to determine the loading conditions (placement and weight of the bag) with optimal and minimal corrections of the affected and unaffected scoliotic spinal regions, respectively. Results: Significant short-term postural correction of scoliosis was achieved through applying an asymmetric load on the ipsilateral shoulder relative to the apex location of the major scoliotic curve. Conclusion: A subject-specific optimal loading configuration was determined using a programming model. The results suggest that the application of a properly controlled asymmetric load carriage might be possible for reducing scoliotic spinal curvature. Further study of the long-term effects of subject-specific optimal asymmetric load carriage on scoliotic spinal curvatures is warranted. Clinical relevance Short-term reduction of scoliotic spinal curvatures under asymmetric load carriage was demonstrated. Thoracic curvatures could be reduced when asymmetric loading was applied on the ipsilateral shoulder relative to the scoliotic apex. Multiobjective programming was applied to determine the optimal weight of asymmetric load for participant with scoliosis.

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Campbell, J. S. "A Code for Reducing Figure-Ground Ambiguities in Tactile Graphics." Journal of Visual Impairment & Blindness 91, no. 2 (March 1997): 175–81. http://dx.doi.org/10.1177/0145482x9709100210.

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This article describes a code that could facilitate the interpretation of tactile outline graphics by reducing potential ambiguities in figure-ground, slope, and curvature. An experiment tested the ability of six blind adults to learn the code quickly, locate and identify all symbols tactilely, and use the code to match embossed drawings to complex models that were designed to present line-referent ambiguities. All the subjects learned the code in less than two hours and successfully matched coded graphics to targeted objects.

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Haigh, Casey D., John H. Crews, Shiquan Wang, and Gregory D. Buckner. "Multi-Objective Design Optimization of a Shape Memory Alloy Flexural Actuator." Actuators 8, no. 1 (February 16, 2019): 13. http://dx.doi.org/10.3390/act8010013.

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This paper presents a computational model and design optimization strategy for shape memory alloy (SMA) flexural actuators. These actuators consist of curved SMA wires embedded within elastic structures; one potential application is positioning microcatheters inside blood vessels during clinical treatments. Each SMA wire is shape-set to an initial curvature and inserted along the neutral axis of a straight elastic member (cast polydimethylsiloxane, PDMS). The elastic structure preloads the SMA, reducing the equilibrium curvature of the composite actuator. Temperature-induced phase transformations in the SMA are achieved via Joule heating, enabling strain recovery and increased bending (increased curvature) in the actuator. Actuator behavior is modeled using the homogenized energy framework, and the effects of two critical design parameters (initial SMA curvature and flexural rigidity of the elastic sleeve) on activation curvature are investigated. Finally, a multi-objective genetic algorithm is utilized to optimize actuator performance and generate a Pareto frontier, which is subsequently experimentally validated.

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Wang, Rong Jie, and Hong Wei Chen. "Analysis and Improvement of Fan Blades Noise." Applied Mechanics and Materials 568-570 (June 2014): 1706–9. http://dx.doi.org/10.4028/www.scientific.net/amm.568-570.1706.

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Fan blades noise is mechanical noise and aerodynamic noise, and the aerodynamic noise is the main noise. Fan's speed, blade number, angle, radius of curvature is the main factor affecting the fan blades noise. Key of control fan noise, should be placed in fan design, Reduce the circumferential velocity, leaned blade, increase the radius of curvature is favorable measures of reducing the noise of the fan blade. Control of noise from the source, will achieve better results.

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Aly, Wael I. A., Hideo Inaba, Naoto Haruki, and Akihiko Horibe. "Drag and Heat Transfer Reduction Phenomena of Drag-Reducing Surfactant Solutions in Straight and Helical Pipes." Journal of Heat Transfer 128, no. 8 (January 23, 2006): 800–810. http://dx.doi.org/10.1115/1.2217751.

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Abstract Flow drag and heat transfer reduction phenomena of non-ionic aqueous surfactant solutions flowing in helical and straight pipes have been experimentally investigated at surfactant solution concentration range of 250-5000ppm and temperature range of 5-20°C. The helically coiled pipes have curvature ratios range of 0.018–0.045. Experimental findings indicate that the friction factors and the heat transfer coefficients of the surfactant solution in helical pipes are significantly higher than in a straight pipe and lower than Newtonian fluid flow like water through the same coils in the turbulent drag reduction region. Drag reduction and heat transfer reduction increase with an increase in surfactant solution concentration and temperature in the measured concentration and temperature ranges. On the other hand, they decrease with increasing of the curvature ratio. A set of empirical expressions for predicting the friction factor and the average Nusselt number for the surfactant solution’s flow through helical and straight pipes have been regressed based on the obtained data in the present experiments.

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Ghisellini, Gabriele, and Nicola Locatelli. "Coherent curvature radiation and fast radio bursts." Astronomy & Astrophysics 613 (May 2018): A61. http://dx.doi.org/10.1051/0004-6361/201731820.

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Fast radio bursts are extragalactic radio transient events lasting a few milliseconds with a ~Jy flux at ~1 GHz. We propose that these properties suggest a neutron star progenitor, and focus on coherent curvature radiation as the radiation mechanism. We study for which sets of parameters the emission can fulfil the observational constraints. Even if the emission is coherent, we find that self-absorption can limit the produced luminosities at low radio frequencies and that an efficient re-acceleration process is needed to balance the dramatic energy losses of the emitting particles. Self-absorption limits the luminosities at low radio frequency, while coherence favours steep optically thin spectra. Furthermore, the magnetic geometry must have a high degree of order to obtain coherent curvature emission. Particles emit photons along their velocity vectors, thereby greatly reducing the inverse Compton mechanism. In this case we predict that fast radio bursts emit most of their luminosities in the radio band and have no strong counterpart in any other frequency bands.

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KANEDA, Shou, Qiang YU, Masaki SHIRATORI, and Keiichi MOTOYAMA. "Optimization Approach for Reducing Sound Power from a Vibrating Plate by Its Curvature Design." JSME International Journal Series C 45, no. 1 (2002): 87–98. http://dx.doi.org/10.1299/jsmec.45.87.

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Nagata, Fusaomi, and Keigo Watanabe. "Feed Rate Control Using Fuzzy Reasoning for a Mold Polishing Robot." Journal of Robotics and Mechatronics 18, no. 1 (February 20, 2006): 76–82. http://dx.doi.org/10.20965/jrm.2006.p0076.

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Reducing time cost of polishing process is a major issue in metallic mold manufacturing. The feed rate, i.e., tangential velocity, of a polishing robot is generally limited to maintain stable contact with workpieces having a large curvature. We propose a feed rate generator using fuzzy reasoning for polishing robots that regulates the feed rate along free-formed surfaces appropriately. The smaller the curvature of the model designed by a 3D CAD, the larger the distance between two adjacent cutter location data (CL data) steps generated by the main processor of CAM. Therefore, given curvature results in acquiring the distance between two adjacent steps of CL data. We also propose a hybrid position/force controller with the feed rate generator enabling the robot to conduct polishing efficiently. Experiments show promising results.

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Tian, Qin, Toshiro Hayashikawa, Jin-Gang Xiong, and Bin Lei. "Seismic Performance of Curved Viaducts with Shock Absorber Devices of Different Stiffness in Great Earthquakes." Journal of Earthquake and Tsunami 12, no. 05 (December 2018): 1850013. http://dx.doi.org/10.1142/s1793431118500136.

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Roller bearings of curved viaducts generate large displacements which lead to damage of bearings or pounding damage at expansion joints between adjacent superstructures. In this study, dispersed steel stoppers are installed near each roller bearing to reduce seismic damage due to large displacements of roller bearings. The concentrated pounding phenomenon between adjacent superstructures can be transferred to the dispersed steel stoppers. Shock absorber devices (SADs) are also installed at each steel stopper to mitigate pounding forces. The effectiveness of SAD stiffness on reducing viaduct damage is analyzed. The pounding forces at steel stopper, displacements on the top of piers, displacements of superstructures, curvatures at pier bases, and the relationships of bending moment and curvature are studied accordingly. The application of SADs with high stiffness can mitigate viaduct damage in earthquakes.

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Wu, Dangzhong, Kaiping Xu, Panpan Guo, Gang Lei, Kang Cheng, and Xiaonan Gong. "Ground Deformation Characteristics Induced by Mechanized Shield Twin Tunnelling along Curved Alignments." Advances in Civil Engineering 2021 (February 3, 2021): 1–17. http://dx.doi.org/10.1155/2021/6640072.

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This paper investigates the ground deformation characteristics induced by mechanized shield twin tunnelling along curved alignments by adopting the nonlinear three-dimensional (3D) finite element method (FEM). The performance of the adopted FEM is demonstrated to be satisfactory by comparing the numerical analysis results with the field monitoring data in a typical case history and with the predicted results generated by a modified version of the Peck’s empirical Gaussian formula. It has been found that the tunnelling-induced transverse ground surface settlement troughs and the distributions of the subsurface horizontal and vertical ground displacements are mostly similar in both form and magnitude for the considered various radii of curvature of tunnel alignment including 50 m, 100 m, 150 m, 200 m, 250 m, 300 m, 400 m, and infinity (i.e., straight-line tunnel). Considering the variational characteristics of the ground deformations with the magnitude of the radius of curvature, the radius of curvature of 100 m can be regarded as a critical tunnel alignment radius of curvature controlling the transformation of the curved tunnelling-induced ground deformational behaviors. For the benefit of geotechnical engineers interested in curved tunnelling with a small radius of curvature, a discussion of the technologies for reducing the overexcavation and improving the accuracy of tunnel lining segment installation is also presented.

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Soukhavong, Sengthong, Tanawat Tangmala, and Ukrit Mankong. "Systematic Reconditioning of Fiber Connector Polishing Process by Reducing Statistical Variance of Connector Characteristics." Applied Mechanics and Materials 781 (August 2015): 98–101. http://dx.doi.org/10.4028/www.scientific.net/amm.781.98.

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Optical connectors with high quality end-face polishes are crucial in future optical access network, where they must meet standard. Common polishing conditions may not always yield best results in any equipment setup due to high statistical variance in the polished connector characteristics. In this paper we propose a systematic approach to recondition the polishing process where we reduce the variance of the fiber height, radius of curvature and apex offset. The approach is enabled by our pneumatic system modification and improved controller design.

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Popken, G., U. Wetterauer, W. Schultze-Seemann, A. B. Deckart, and H. Sommerkamp. "A modified corporoplasty for treating congenital penile curvature and reducing the incidence of palpable indurations." BJU International 83, no. 1 (June 28, 2008): 71–75. http://dx.doi.org/10.1046/j.1464-410x.1999.00887.x.

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Cao, Shu Kun, Li Song, Kai Feng Song, Jie Lv, and Xiu Sheng Chen. "Free-Form Surface Five-Axis Machining Tool Path and Tool Posture Simultaneous Multi-Objective Optimization Theory Research." Key Engineering Materials 467-469 (February 2011): 900–905. http://dx.doi.org/10.4028/www.scientific.net/kem.467-469.900.

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In view of all sorts of questions existing in CNC machining, such as machining vibration, so proposed a new simultaneous multi-objective optimization algorithm on free-form surface five-axis machining tool path and tool posture based on constant scallop height. In the algorithm, we first complete the surface fitting on the base of feature points obtained. Secondly calculate principal curvatures of the surface, select tools, and at the same time generate tool axis vector in the current cutter-contact point tool axis. Once again get the maximum spacing and surface curvature in accordance with the tool effective cutting radius, discrete into cutter-contact point, and calculate the cutting depth to adjust the machine feed rate. And finally connect adjacent curve path using the diagonal to achieve a continuous cutting scallop height tool path. This algorithm can achieve the goals such as the same precision, improving processing efficiency, reducing the number of tool cutting in and out, reducing cutting vibration and tool wear and so on. That is the algorithm can achieve simultaneous multi-objective optimization of the free-form surface NC machining finally.

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Kreuter, A., S. Wuttke, and M. Blumthaler. "Improving Langley calibrations by reducing diurnal variations of aerosol Ångström parameters." Atmospheric Measurement Techniques 6, no. 1 (January 14, 2013): 99–103. http://dx.doi.org/10.5194/amt-6-99-2013.

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Abstract. Errors in the sun photometer calibration constant lead to artificial diurnal variations, symmetric around solar noon, of the retrieved aerosol optical depth (AOD) and the associated Ångström exponent α and its curvature γ. We show in simulations that within the uncertainty of state-of-the-art Langley calibrations, these diurnal variations of α and γ can be significant in low AOD conditions, while those of AOD are negligible. We implement a weighted Monte Carlo method of finding an improved calibration constant by minimizing the diurnal variations in α and γ and apply the method to sun photometer data of a clear day in Innsbruck, Austria. The results show that our method can be used to improve the calibrations in two of the four wavelength channels by up to a factor of 3.6.

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Kreuter, A., S. Wuttke, and M. Blumthaler. "Improving Langley calibrations by reducing diurnal variations of aerosol Ångström parameters." Atmospheric Measurement Techniques Discussions 5, no. 5 (September 7, 2012): 6479–92. http://dx.doi.org/10.5194/amtd-5-6479-2012.

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Abstract. Errors in the sun photometer calibration constant lead to artificial diurnal variations, symmetric around solar noon, of the retrieved Aerosol Optical Depth (AOD) and the associated Ångström exponent α and its curvature γ. We show in simulations that within the uncertainty of state-of-the-art Langley calibrations, these diurnal variations of α and γ can be significant in low AOD conditions, while those of AOD are negligible. We implement a weighted Monte-Carlo method of finding an improved calibration constant by minimizing the diurnal variations in α and γ and apply the method to sun photometer data of a clear day in Innsbruck, Austria. The results show that our method can be used to improve the calibrations in two of the four wavelength channels by up to a factor of 3.6.

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Mu, Yanming, and Zongde Fang. "Design and analysis of high contact ratio spiral bevel gears by modified curvature motion method." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 232, no. 19 (October 30, 2017): 3396–409. http://dx.doi.org/10.1177/0954406217737803.

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This paper presents a new method to design a seventh-order transmission error for high contact ratio spiral bevel gears by the modified curvature motion method to reach the purpose of reducing or eliminating gear vibration and noise. In this paper, firstly, based on the predesigned seventh-order transmission error, the polynomial coefficients of transmission error curve can be obtained. Secondly, a method named modified curvature motion method is used to generate the spiral bevel gear with the predesigned transmission error. Lastly, based on TCA and LTCA, we verify the feasibility of the modified curvature motion method to generate spiral bevel gear with seventh-order transmission error, and the meshing impact of gear set with the seventh-order and second-order function of transmission error is analyzed and compared. The results of a numerical example show that the seventh-order transmission error acquired by the modified curvature motion method can effectively reduce the meshing impact of spiral bevel gears. The tooth modiﬁcation method and meshing impact analysis method can serve as a basis for developing a general technique of ﬂank modiﬁcation for spiral bevel gears.

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Lin, Nan, and Shuming Shi. "Road grade estimation based on the curvature of the vertical profile of a road." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 231, no. 4 (August 5, 2016): 476–86. http://dx.doi.org/10.1177/0954407016640636.

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A road grade estimation model which uses the curvature to express the rate of change in the grade is proposed in this paper. The assumption that the rate of change in the road grade equals zero is widely accepted in the field of online road grade estimation. This assumption is reasonable to some extent, but it results in an inevitable time lag in the rolling-hills situation. This paper offers a road curvature estimation method which can be used to express the rate of change in the road grade. The recursive least-squares algorithm is used to the estimate the curvature, and then the Kalman filter is employed to estimate the road grade from the other vehicle states. Field tests are performed on a highway in a mountainous area. The offline road grade is used to analyse the instantaneous error and the time lag. The field test results show that the model performs well in reducing the time lag, especially in periods where the gradient changes rapidly.

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Cerrato, Robert M. "Analysis of Nonlinearity Effects in Expected-Value Parameterizations of the von Bertalanffy Equation." Canadian Journal of Fisheries and Aquatic Sciences 48, no. 11 (November 1, 1991): 2109–17. http://dx.doi.org/10.1139/f91-250.

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Using curvature measures, this study provides direction on exploiting the full potential of two expected-value parameterizations of the von Bertalanffy equation in reducing nonlinearity effects. This study also examines the relationship between the curvature measures and characteristics of growth data for these parameterizations. Empirical analysis of a diverse set of growth data suggests that, on average, a threefold reduction in the maximum parameter effects curvature can be achieved by simply defining one parameter as the expected mean size of an intermediate age-class, rather than as the oldest age-class in the sample. It is also found that samples in which there are proportionally more size measurements in the younger age-classes relative to the older age-classes tend to have lower nonlinearity effects. Results can be applied to existing growth data which would otherwise yield unacceptably biased and nonnormal parameter estimates and to reduce the effort required in producing accurate confidence regions.

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Tunç, Y. "THU0403 THE EFFECT OF SPINAL STABILIZATION EXERCISES ON SPINAL CURVES DIAGNOSED WITH ANKYLOSING SPONDYLITIS." Annals of the Rheumatic Diseases 79, Suppl 1 (June 2020): 439.2–439. http://dx.doi.org/10.1136/annrheumdis-2020-eular.6458.

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Background:Postural deformities can cause changes in spinal curvatures patients with ankylosing spondylitis. In these patients, preventive and therapeutic approaches are needed for spinal deformities (1). Positive effects of the spinal stabilization exercises are manifested in reducing pain, maintaining mobility, improving posture, increasing aerobic capacity and improving quality of life (2).Objectives:The aim of this study is to investigate the effect of stabilization exercises on spinal curvatures in s ankylosing spondylitis patients.Methods:Twenty-eight ankylosing spondylitis patients (25 females, 3 males) with a mean age of 30.87 ± 9.13 years were included in the stabilization exercises program. The patients performed spinal stabilization exercises two days a week for six weeks. Stabilization training includes training of deep muscles providing diaphragmatic breathing, neutral spine position control training and local motor control, and motor control training of global muscles, dynamic stabilization exercises and strengthening training. Thoracic kyphosis and lumbar lordosis curvature of patients in an upright position were evaluated with Spinal Mouse (SM) device before and after therapy program. The SM device is a reliable, valid, safe, quick method that can be used in the clinics and researches of the adults with no side effects.Results:At the end of 6 weeks of treatment, there was a decrease in the total curvature degree of the thoracic vertebrae in the sagittal axis (p=0.026). No significant difference was found in the lumbal region (p= 0.109).Table 1.Differences of Total Curve DegreesPre-Exercises ProgramMean±SDPost-ExercisesProgramMean±SDzpThoracal Total Curve Degrees43.50±8.1142.57±7.70-2.232*0.026Lumbal Total Curve Degrees-26.42±8.46-23.77±7.15-1.6040.109*p<0.05, SD: Standart DeviationConclusion:Stabilization exercises are effective in reducing thoracic kyphosis in patients with ankylosing spondylitis patients. The use of these exercises in treatment programs will contribute significantly to improving spinal alignment and preventing postural deformities.References:[1]Grazio, S., Grubišić, F., & Brnić, V. (2019). Rehabilitation of patients with spondyloarthritis: a narrative review.Medicinski Glasnik,16(2).[2]Gunay, S. M., Keser, I., & Bicer, Z. T. (2018). The effects of balance and postural stability exercises on spa based rehabilitation programme in patients with ankylosing spondylitis.Journal of back and musculoskeletal rehabilitation,31(2), 337-346.Disclosure of Interests: :None declared

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Foti, Dora. "Dynamic Identification Techniques to Numerically Detect the Structural Damage." Open Construction and Building Technology Journal 7, no. 1 (July 12, 2013): 43–50. http://dx.doi.org/10.2174/1874836801307010043.

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Damage detection in civil engineering structures using changes in measured modal parameters is an area of research that has received notable attention in literature in recent years. In this paper two different experimental techniques for predicting damage location and severity have been considered: the Change in Mode Shapes Method and the Mode Shapes Curvature Method. The techniques have been applied to a simply supported finite element bridge model in which damage is simulated by reducing opportunely the flexural stiffness EI. The results show that a change in modal curvature is a significant damage indicator, while indexes like MAC and COMAC – extensively and correctly used for finite element model updating - lose their usefulness in order to damage detection.

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Kolanowski, Bogdan, Jacek Augustyniak, and Dorota Latos. "Cartographic Line Generalization Based on Radius of Curvature Analysis." ISPRS International Journal of Geo-Information 7, no. 12 (December 12, 2018): 477. http://dx.doi.org/10.3390/ijgi7120477.

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Cartographic generalization is one of the important processes of transforming the content of both analogue and digital maps. The process of reducing details on the map has to be conducted in a planned way in each case when the map scale is to be reduced. As far as digital maps are concerned, numerous algorithms are used for the generalization of vector line elements. They are used if the scale of the map (on screen or printed) is changed, or in the process of smoothing vector lines (e.g., contours). The most popular method of reducing the number of vertices of a vector line is the Douglas-Peucker algorithm. An important feature of most algorithms is the fact that they do not take into account the cartographic properties of the transformed map element. Having analysed the existing methods of generalization, the authors developed a proprietary algorithm that is based on the analysis of the curvature of the vector line and fulfils the condition of objective generalization for elements of digital maps that may be used to transform open and closed vector lines. The paper discusses the operation of this algorithm, along with the graphic presentation of the generalization results for vector lines and the analysis of their accuracy. Treating the set of verification radii of a vector line as a statistical series, the authors propose applying statistical indices of position of these series, connected with the shape of the vector line, as the threshold parameters of generalization. The developed algorithm allows for linking the generalization parameters directly to the scale of the topographic map that was obtained after generalization. The results of the operation of the algorithm were compared to the results of the reduction of vertices with use of the Douglas-Peucker algorithm. The results demonstrated that the proposed algorithm not only reduced the number of vertices, but that it also smoothed the shape of physiographic lines, if applied to them. The authors demonstrated that the errors of smoothing and position of vertices did not exceed the acceptable values for the relevant scales of topographic maps. The developed algorithm allows for adjusting the surface of the generalized areas to their initial value more precisely. The advantage of the developed algorithm consists in the possibility to apply statistical indices that take the shape of lines into account to define the generalization parameters.

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Fu, Xiu Hua, Yang Liu, and Zong He Jia. "Analysis of a New Processing Method for Small Curvature Aaspheric." Advanced Materials Research 1089 (January 2015): 309–14. http://dx.doi.org/10.4028/www.scientific.net/amr.1089.309.

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For the aspheric processing is complex , time consuming and difficult to guarantte the eccentricity ,this paper introduce a new method of aspheric processing --repairing and polishing methed and describe the principle . Best fit radius, removal function were computed by mathematical model method and the respective performance curves were given by simulation. This methed has the particular advantage of shortening the working time ,reducing the eccentric amount of the element and improving the processing efficiency. Through this processing method, do a series of processing experiments on the smaller aspheric tolerance single crystal silicon aspheric.As the result indicated , plane surface shape error PV 0.52 μm,surface roughness RMS value of single-crystal silicon 0.09 μm ,the center deviation was less than1μm and the surface smoothness meet the standard above the grade Π.

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Vogler, Christoph, Claas Abert, Florian Bruckner, and Dieter Suess. "Efficiently reducing transition curvature in heat-assisted magnetic recording with state-of-the-art write heads." Applied Physics Letters 110, no. 18 (May 2017): 182406. http://dx.doi.org/10.1063/1.4981805.

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Ibriksz, Tamás, and Ferenc Tancsics. "Correlations between Forging Tool Lifetime and the Continuous Curvature Transitions." Acta Technica Jaurinensis 12, no. 4 (October 18, 2019): 306–20. http://dx.doi.org/10.14513/actatechjaur.v12.n4.521.

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The forged work-piece geometry is determined by different standards and bilateral specifications, so the geometry is not allowed to be changed by the technologist according to their own decision. Therefore, the lifetime of the tool which gives the final geometry is a key issue. The tool lifetime is mainly influenced by technology and process parameters. Regarding these parameters, there are many classical optimization solutions available to increase tool life. In our work, we have looked for a technical device that can complement classic solutions to further enhance the effectiveness in the field of forging tools lifetime. In our opinion, such a technical device may be a continuous curvature of the surface transitions at the preformed geometry. In our work, we investigated the effect of the continuous curvature for a function reducing the forging work at a real geometry.

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Mientjes, Martine I. V., and Robert W. Norman. "Effects of lumbar curvature on low back pain risk factors during repetitive postural loading." Occupational Ergonomics 3, no. 1 (March 20, 2003): 3–17. http://dx.doi.org/10.3233/oer-2003-3102.

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Effects of lumbar spine curvature on reducing risk factors for reporting low back pain (LBP) at work were assessed for a "light" but repetitive simulated workplace assembly job. Nine women stood at a target trunk angle of 30° and assembled plastic toys on a table for 25 minutes in one minute work cycles, at a work/recovery ratio of 55/5 seconds. Flexed (rounded back) postures, often observed in industry, and lordotic (hollow back) postures maintained by back extensor muscles and proposed to reduce risk by reducing shear forces, were studied. Spinal loading was imposed by torso weight only. Twenty-five minutes of this simulated job produced discomfort scaled as "strong" to "very strong" regardless of spinal posture. Lordosis required median EMGs of 15% MVC. Flexed postures lowered back extensor EMG to as little as 5% MVC but not to zero. This apparently "light" job seems to expose people to quite high risk of reporting LBP (estimated at about 80%), mainly because of high cumulative spine loads, regardless of the spinal posture adopted.

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Yu, Xiang Long, Quan Yang, and Zheng Yi Jiang. "Analysis of Plate Bending in Coilbox by Finite Element Method." Key Engineering Materials 443 (June 2010): 146–51. http://dx.doi.org/10.4028/www.scientific.net/kem.443.146.

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Using finite element method (FEM), the results of bending conditions of the intermediate plate at the bending rolls of a coilbox between the roughing and finishing stands in a hot strip mill were obtained. The intermediate plate was coiled in a coilbox, which effectively overcame the problem of temperature drop by reducing surface area exposed to radiant heat loss during the waiting period. Different states of the plate in the coilbox were simulated by FEM, and the mathematical model of the bending rolls was established, which was in accord with the simulation results that the plate was coiled. As the bending shape of the front end of the intermediate plate is crucial to coiling process, the curvatures of the plate were predicted through FEM. In addition, the roll diameter and arrangement affect the optimum curvature, thus the parameters for bending rolls were determined without many adjustments. The developed bending model has been applied to actual coilbox in plant.

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Zuo, Xi, Guo Xing Chen, and Wei Qian Li. "Studies on Damage Distinguishing of Underground Tunnel Structure Based on BP Neural Network." Applied Mechanics and Materials 580-583 (July 2014): 1382–87. http://dx.doi.org/10.4028/www.scientific.net/amm.580-583.1382.

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With the expansion and development of scale of construction on metro engineering, the damage diagnosis and the safety evaluation on underground engineering structure have become vital problems to be solved. This paper raised an idea to distinguish underground engineering structure based on BP neural network: define change rate of curvature of structure, and recognize it as the input scalar of BP neural network, using a reducing unit elastic modulus method to simulate damage location and damage degree, through various set of underground structure extent of damage, recognize the first four order curvature structure change rate as input of BP neural network. The results show that the method using BP neural network can identify the damage degree of underground engineering structure accurately and can solve the damage identification problem of underground engineering structure conveniently and effectively.

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Sakamoto, Kazutami, Takeshi Kitano, Haruka Kuwahara, Megumi Tedani, Kenichi Aburai, Shiroh Futaki, Masahiko Abe, Hideki Sakai, Hiroyasu Ohtaka, and Yuji Yamashita. "Effect of Vesicle Size on the Cytolysis of Cell-Penetrating Peptides (CPPs)." International Journal of Molecular Sciences 21, no. 19 (October 7, 2020): 7405. http://dx.doi.org/10.3390/ijms21197405.

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A specific series of peptides, called a cell-penetrating peptide (CPP), is known to be free to directly permeate through cell membranes into the cytosol (cytolysis); hence, this CPP would be a potent carrier for a drug delivery system (DDS). Previously, we proposed the mechanism of cytolysis as a temporal and local phase transfer of membrane lipid caused by positive membrane curvature generation. Moreover, we showed how to control the CPP cytolysis. Here, we investigate the phospholipid vesicle’s size effect on CPP cytolysis because this is the most straightforward way to control membrane curvature. Contrary to our expectation, we found that the smaller the vesicle diameter (meaning a higher membrane curvature), the more cytolysis was suppressed. Such controversial findings led us to seek the reason for the unexpected results, and we ended up finding out that the mobility of membrane lipids as a liquid crystal is the key to cytolysis. As a result, we could explain the cause of cytolysis suppression by reducing the vesicle size (because of the restriction of lipid mobility); osmotic pressure reduction to enhance positive curvature generation works as long as the membrane is mobile enough to modulate the local structure. Taking all the revealed vital factors and their effects as a tool, we will further explore how to control CPP cytolysis for developing a DDS system combined with appropriate cargo selection to be tagged with CPPs.

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Kazantsev, A. A., B. A. Samorodov, and A. M. Terentev. "Methodological Approach to Reducing the Radar Cross Section of Local Scatterer under Given Frequency-Angular Observation Conditions." Ural Radio Engineering Journal 5, no. 2 (2021): 162–78. http://dx.doi.org/10.15826/urej.2021.5.2.005.

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This paper focuses on application of spectral estimation methods for scattering center’s radar cross section estimation and reduction under given frequency-angular observation conditions. A methodological approach has been developed to reduce the local center’s radar cross section with given object overall dimensions. The developed methodological approach is based on parametric optimization of object geometry, firstly, to reduce the local scatterer radar cross section and, secondly, to maximize object payload. The problem overview is presented in the introduction. The first section is devoted to mathematical formulation of the problem. The following section includes the comparison analysis of the different types of geometrical shapes. As a result, the object with exponential profile is chosen as the best one due to the ability to manage rear vertex local scatterer amplitude by changing the curvature parameter. In the third section the optimal curvature parameter value of the exponential profile is justified for the given object overall dimensions and frequency-angular observation conditions. It is demonstrated that the main characteristic to analysis is two-dimension functional dependence of the local scatterer mean radar cross section from geometrical parameter and angle of observation. It is proved that this mentioned dependence may be received by the implementation such well-known spectral estimation method as CLEAN to the object sinogram. The recognition range is calculated for two different hypothetical radars to assert the efficiency. It is offered in the conclusion to complicate the developed approach with radio absorption materials implementation as the direction of the future investigations.

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Šliseris, Jānis, and Kārlis Rocēns. "CURVATURE ANALYSIS FOR COMPOSITE WITH ORTHOGONAL, ASYMMETRICAL MULTI‐LAYER STRUCTURE." JOURNAL OF CIVIL ENGINEERING AND MANAGEMENT 16, no. 2 (June 30, 2010): 242–48. http://dx.doi.org/10.3846/jcem.2010.28.

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An option for reducing material consumption in bent construction is flat plate replacement with a curved or saddle shaped plate (shell). This option applies to plywood sheet, provided that the curved or saddle shaped plates are made in widely used multilevel plywood presses with parallel shelves using layers with an appropriate physical properties, geometric dimensions and orientation, creating a structurally asymmetrical sheet, relative to mid‐surface. Improved currently used method for calculation of curvature with taking into account curvature interaction effect and elastic characteristic change in moisture changing process. Compared results obtained by improved method and finite element method. Using improved method calculated values of curvature for a sheet with different geometrical properties and moisture conditions. Santrauka Lenkiamuju konstrukciju medžiagu sanaudas mažina plokščio lakšto pakeitimas sulenktu arba balno pavidalo lakštu (kevalu). Šis pasirinkimas taikomas klijuotes lakštams užtikrinus, kad sulenkti arba balno pavidalo lakštai yra padaromi naudojant keliu lygiu klijuotes presus su lygiagrečiomis lentynomis, imant tinkamu fizikiniu savybiu, geometriniu matmenu ir orientavimo sluoksnius bei sukuriant struktūriškai asimetrinius lakštus, susijusius su viduriniu paviršiumi. Patobulintas dabar taikomas metodas kreivumui skaičiuoti, atsižvelgiant i kreivumo saveikos poveiki ir dregnio kitimo vyksmo tampruji būdingaji pokyti. Palyginti rezultatai, gauti patobulintu ir baigtiniu elementu metodais. Taikant patobulinta metoda, apskaičiuotos kreivumo reikšmes lakštams, kuriu yra ivairūs geometriniai rodikliai ir ivairios dregnumo salygos.

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Xu, Xiangyang, Yinghua Liang, Shumiao Zuo, Peter Tenberge, Peng Dong, Yanfang Liu, Shuhan Wang, and Zhuo Wang. "A novel tooth tip relief method for reducing micro-pitting of spur gears." Advances in Mechanical Engineering 13, no. 9 (September 2021): 168781402110446. http://dx.doi.org/10.1177/16878140211044641.

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Micro-pitting is a common fatigue failure mode of spur gears. To reduce it, this paper proposes a novel tooth tip relief method. Gear meshing simulation is firstly performed considering the actual contact path, showing that there are four Hertz contact stress peaks in the transition areas of the tooth flank. Equations are then developed for the novel tooth tip relief method: one focuses on the smooth transition between the involute profile and the tip relief region, the other on the smooth transition between the tip relief region and the tooth tip. The results of curvature radius and Hertz contact stress show that the proposed novel method can effectively reduce the Hertz contact stress peaks, which indicates this tip relief method could benefit for reducing the micro-pitting. Finally, both wear simulations and bench tests are conducted, verifying the effectiveness of the proposed method for reducing the micro-pitting of spur gears.

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Ng, Jimmy Wui Guan, Benjamin V. Bloch, and Peter J. James. "Sagittal radius of curvature, trochlea design and ultracongruent insert in total knee arthroplasty." EFORT Open Reviews 4, no. 8 (August 2019): 519–24. http://dx.doi.org/10.1302/2058-5241.4.180083.

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Multi radius (MR) total knee arthroplasty (TKA) has been associated with mid-flexion instability. Single radius (SR) TKA may provide better anteroposterior stability through single flexion axis and biomechanical advantage for quadriceps function. Medial pivot (MP) TKA and gradually reducing (GR) radius TKA produce better knee kinematics. Clinical outcomes are equivalent for SR, MR and MP TKA. Short-term studies have shown better clinical outcomes and kinematics for GR TKA. Thinner and narrow anterior flange, deeper trochlea groove and more anatomical trochlea design reduces patellofemoral complications in TKA Ultracongruent inserts provide comparable clinical outcomes to posterior-stabilized TKA and cruciate retaining TKA.Cite this article: EFORT Open Rev 2019;4:519-524. DOI: 10.1302/2058-5241.4.180083

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Maghfiroh, Hari, Oyas Wahyunggoro, Adha Imam Cahyadi, Kuo Lung Lian, and Bwo Ren Ke. "Speed Control of a Single Taipei Mass Rapid Transit System Train by Using a Single Input Fuzzy Logic Controller." International Journal of Electrical and Computer Engineering (IJECE) 6, no. 2 (April 1, 2016): 621. http://dx.doi.org/10.11591/ijece.v6i2.8123.

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The purpose of this study was to design a speed controller for mass rapid transit (MRT) train by using a single input fuzzy logic controller (SIFLC). A complete train model, which was designed according to the design of a Taipei MRT train was used for analyzing both mechanical and electrical parts. The SIFLC was used for improving a fuzzy logic controller (FLC) by reducing its number of control rules. The results indicated that the SIFLC exhibited more favorable performance than the FLC did and a substantial reduction in the number of fuzzy rules and processing time. Therefore, tuning the SIFLC was easier compared with tuning the FLC; furthermore, the simulation time of the SIFLC was shorter than that of the FLC, exhibiting reductions of up to 17.3% in a constant track (track without gradient and curvature) and up to 12.27% in a variable track (track with gradient and curvature).

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Maghfiroh, Hari, Oyas Wahyunggoro, Adha Imam Cahyadi, Kuo Lung Lian, and Bwo Ren Ke. "Speed Control of a Single Taipei Mass Rapid Transit System Train by Using a Single Input Fuzzy Logic Controller." International Journal of Electrical and Computer Engineering (IJECE) 6, no. 2 (April 1, 2016): 621. http://dx.doi.org/10.11591/ijece.v6i2.pp621-629.

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The purpose of this study was to design a speed controller for mass rapid transit (MRT) train by using a single input fuzzy logic controller (SIFLC). A complete train model, which was designed according to the design of a Taipei MRT train was used for analyzing both mechanical and electrical parts. The SIFLC was used for improving a fuzzy logic controller (FLC) by reducing its number of control rules. The results indicated that the SIFLC exhibited more favorable performance than the FLC did and a substantial reduction in the number of fuzzy rules and processing time. Therefore, tuning the SIFLC was easier compared with tuning the FLC; furthermore, the simulation time of the SIFLC was shorter than that of the FLC, exhibiting reductions of up to 17.3% in a constant track (track without gradient and curvature) and up to 12.27% in a variable track (track with gradient and curvature).

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Nowakowski, Christopher, Dana Friedman, and Paul Green. "An Experimental Evaluation of Using Automotive HUDs to Reduce Driver Distraction While Answering Cell Phones." Proceedings of the Human Factors and Ergonomics Society Annual Meeting 46, no. 22 (September 2002): 1819–23. http://dx.doi.org/10.1177/154193120204602209.

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To examine strategies for reducing driver distraction while answering the phone, 24 participants answered calls while driving a simulator. Calls were answered using a center-console-mounted phone or one of several phone designs which utilized a HUD to display the caller ID and steering-wheel-mounted buttons to activate the phone. Driving workload was manipulated by varying the curve radius and by varying the timing of the call, either 1 second before or 5 seconds after the start of a curve. The HUD-based phones resulted in response times that were 39 percent faster than the conventional center-console phone, and they resulted in up to 62 percent fewer line crossings. Additionally, when using the center-console phone, road curvature had a large influence on response times and driving performance; however, the HUD-based phone were less sensitive to increased road curvature or driving workload.

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Kang, Min Woo, and Woo Young Choi. "Investigation on the Hump Behavior of Gate-Normal Nanowire Tunnel Field-Effect Transistors (NWTFETs)." Applied Sciences 10, no. 24 (December 11, 2020): 8880. http://dx.doi.org/10.3390/app10248880.

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The hump behavior of gate-normal nanowire tunnel field-effect transistors (NWTFETs) is investigated by using a three-dimensional technology computer-aided design (TCAD) simulation. The simulation results show that the hump behavior degrades the subthreshold swing (SS) and on-current (Ion) because the corners and sides of nanowires (NWs) have different surface potentials. The hump behavior can be successfully suppressed by increasing the radius of curvature (R) of NWs and reducing gate insulator thickness (Tins).

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Huang, Jun, Xiuhui Wang, and Jun Wang. "Mesh simplification algorithm based on edge curvature metrics and local optimization." International Journal of Modeling, Simulation, and Scientific Computing 11, no. 01 (January 23, 2020): 1950042. http://dx.doi.org/10.1142/s1793962319500429.

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Aiming at the problem that the mesh simplification algorithm loses the geometric features of the model in large-scale simplification, an improved half-edge collapse mesh simplification algorithm is proposed. The concept of approximate measurement of edge curvature is introduced, and the edge curvature is added to the error measure, so that the order of half-edge collapse of the mesh is changed, and the simplified details of the mesh model can be preserved accurately. At the same time, by analyzing the quality of simplified triangular mesh, optimizing triangular mesh locally, reducing the amount of narrow triangles, the quality of the simplified model is improved. The proposed algorithm was tested on Cow model, Car model and Bunny model, and compared with another three algorithms, one of them is a classical mesh simplification algorithm based on edge collapse, the other is an improved algorithm of the classical one. The experimental results show that the improved algorithm can better retain the detail features of the original model at the same reduction ratio, and has reasonable mesh allocation, fast execution speed and small error.

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Journal articles on the topic 'Reducing curvature'

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