The impact of lateral bow angle variation on an archer’s score

2021 ◽  
pp. 175433712110370
Author(s):  
James L Park
Keyword(s):  
Lateral Position ◽  
Skill Level ◽  
Target Distance ◽  
Substantial Portion ◽  
Angle Variation ◽  
Lateral Angle ◽  
The Impact ◽  
Loss Mechanisms

Variation of the bow’s lateral angle (‘bow cant’ angle) affects the lateral position of arrows on the target, thus impacting an archer’s score. The displacement of arrows on the target depends approximately on the target distance squared and is hence of greatest impact at longer distances. A total of eight archers participated in this study, ranging in skill level from three who have performed at the highest levels internationally through to competent club-level archers, plus the author. The bow cant variation was measured and the impact on archers’ scores was calculated, assuming no other score loss mechanisms. The results show that the score loss associated with bow cant angle can be a substantial portion of an archer’s total score loss, particularly for elite archers using recurve bows.

The impact of off-centred groups on an archer’s score

2020 ◽  
pp. 175433712096632
Author(s):  
James L Park
Keyword(s):  
Monte Carlo ◽  
Normal Distribution ◽  
Vertical Axis ◽  
Skill Level ◽  
Monte Carlo Technique ◽  
Target Distance ◽  
Using Data ◽  
The Impact

Archers frequently lose score by having their sights set incorrectly, resulting in off-centre groups on the target and lower scores than would otherwise have been possible. The archer’s group on the target has been modelled using a normal distribution where the size of the archer’s group depends upon the archer’s skill level and target distance. Off-centred groups were modelled by varying the arrow positions on the vertical axis and the score loss at the usual competition distances using a Monte Carlo technique. A method of using the centroid of each three or six-arrow end is used to optimise the sight setting and minimise score loss, realising that this is done using data from a very limited number of shots. It is best to correct for only a portion of the error for each end, rather than for the full error.

Minimising the impact of arrow mass and stiffness variations on an archer’s score

2021 ◽  
pp. 175433712110165
Author(s):  
James Park
Keyword(s):  
Monte Carlo ◽  
Standard Deviation ◽  
Normal Distribution ◽  
Skill Level ◽  
Monte Carlo Technique ◽  
Target Distance ◽  
The Impact

A Monte Carlo technique was used to study the arrow mass and stiffness tolerances necessary to minimise the degradation of an archer’s likely score at normal competition distances. The archer’s arrow groups on the target were modelled using a half-normal distribution, where the standard deviation of the arrow’s distance from the centre depends upon the archer’s skill level and target distance. Equipment tolerances were modelled by varying the arrow positions on the target in either or both the vertical and lateral axes. This study showed that score loss due to arrow tolerance can be reduced well below score losses resulting from other sources by matching arrow mass to ±0.5 grains and arrow stiffness to ±1%.

Estimation of uncertainties in fault lateral positioning on 3D PSDM seismic image: an example from the North West Shelf

2016 ◽  
Vol 56 (2) ◽  
pp. 556
Author(s):  
Sergey Birdus ◽  
Vincent Ganivet ◽  
Alexey Artemov ◽  
Ray Teakle ◽  
Paul Phythian
Keyword(s):  
Practical Interest ◽  
Velocity Model ◽  
Lateral Position ◽  
Second Step ◽  
North West ◽  
The North ◽  
Seismic Image ◽  
Estimation Of Uncertainties ◽  
The Impact ◽  
Lateral Positioning

This extended abstract presents a two-step sequence to estimate uncertainties in lateral positioning of fault planes on 3D PSDM (pre-stack depth migration) seismic images. This analysis can be applied to any localised detail on a seismic image but, in the majority of geological settings, it is most important for the faults. The first step provides an approximate evaluation of what causes the uncertainties, how the uncertainties are distributed in a 3D space, and what to expect within target zones. The authors assume that every complex detail within a 3D PSDM velocity model causes some uncertainties to the seismic image below. Thus, the uncertainties at a target level depend on the complexity of the overburden and the seismic acquisition parameters. At this step a qualitative 3D volume of lateral fault position uncertainties is created. In the second step the authors focus on a single fault of practical interest. Based on the results of the first step, the authors modify the existing 3D PSDM anisotropic velocity model by introducing additional anomalies that cause maximal changes to the lateral position of the fault on seismic image. Then the authors iteratively re-migrate a small sub-volume around the fault and check the PSDM images and residual moveout. The objective is to find out how far the velocity variations can move the image of the fault and still satisfy available seismic data. The second step gives more reliable quantitative estimations of the impact of velocity on fault positioning. A real multi-azimuth 3D seismic dataset from the North West Shelf is used to illustrate this sequence.

Efficient Optical Couplings for Fiber-Distributed Solar Lighting

Solar Energy ◽  
2003 ◽  
Author(s):  
L. C. Maxey ◽  
M. R. Cates ◽  
S. L. Jaiswal
Keyword(s):  
Optical Fibers ◽  
Optical Waveguides ◽  
Large Core ◽  
Index Matching ◽  
Refractive Index Matching ◽  
Solar Lighting ◽  
The Individual ◽  
Insertion Losses ◽  
The Impact ◽  
Loss Mechanisms

Optical couplings in large core optical waveguides have many similarities with those in conventional optical fibers but pose some unconventional challenges as well. The larger geometry, looser manufacturing tolerances and reduced dimensional stability compound the problems associated with making low-loss couplings in large core waveguides. The individual factors contributing to coupling losses are discussed to develop an understanding of the extant loss mechanisms. Individual methods and materials employed to mitigate the impact of each of the dominant loss mechanisms are discussed in detail. A combination of endface geometry control, axial alignment constraint and refractive index matching are employed to produce highly efficient optical couplings in large core waveguides. The combination of these elements has significantly reduced the insertion losses due to connector couplings. Prior to implementing the current methods losses of 15% and greater were common but these have been reduced to 2%–5% with the current methods.

Impact of Time-Resolved Entropy Measurement on a One-and-One-Half-Stage Axial Turbine Performance

2011 ◽  
Vol 134 (2) ◽  
Author(s):  
M. Mansour ◽  
N. Chokani ◽  
A. I. Kalfas ◽  
R. S. Abhari
Keyword(s):  
Fast Response ◽  
Loss Coefficient ◽  
Time Resolved ◽  
Axial Turbine ◽  
Pressure Loss Coefficient ◽  
Entropy Measurement ◽  
High Pressure Stage ◽  
Turbine Design ◽  
The Impact ◽  
Loss Mechanisms

An accurate assessment of unsteady interactions in turbines is required, so that this may be taken into account in the design of the turbine. This assessment is required since the efficiency of the turbine is directly related to the contribution of unsteady loss mechanisms. This paper presents unsteady entropy measurements in an axial turbine. The measurements are conducted at the rotor exit of a one–and-one-half-stage unshrouded turbine that is representative of a highly loaded, high-pressure stage of an aero-engine. The unsteady entropy measurements are obtained using a novel miniature fast-response probe, which has been developed at ETH Zurich. The entropy probe has two components: a one-sensor fast-response aerodynamic probe and a pair of thin-film gauges. The probe allows the simultaneous measurement of the total temperature and the total pressure from which the time-resolved entropy field can be derived. The measurements of the time-resolved entropy provide a new insight into the unsteady loss mechanisms that are associated with the unsteady interaction between rotor and stator blade rows. A particular attention is paid to the interaction effects of the stator wake interaction, the secondary flow interaction, and the potential field interaction on the unsteady loss generation at the rotor exit. Furthermore, the impact on the turbine design of quantifying the loss in terms of the entropy loss coefficient, rather than the more familiar pressure loss coefficient, is discussed in detail.

Influences of Gesture-Based Mobile Phone Use While Driving

2021 ◽  
pp. 036119812110263
Author(s):  
Jianwei Niu ◽  
Yulin Zhou ◽  
Dan Wang ◽  
Xingguo Liu
Keyword(s):  
Mobile Phone ◽  
Lateral Position ◽  
Driving Safety ◽  
Control Technique ◽  
Steering Wheel ◽  
Secondary Tasks ◽  
Mobile Phone Use ◽  
Driving Speed ◽  
Gesture Control ◽  
The Impact

The use of mobile phones while driving has been a hot topic in the field of driving safety for decades. Although there are few studies on the influence of gesture control on in-vehicle secondary tasks, this study aims to investigate the impact of gesture-based mobile phone use without touching while driving from the perspective of multiple-resource workload owing to visual, auditory, cognitive, and psychomotor resource occupation. A novel gesture control technique was adopted for secondary task interactions, to recognize the gestures of drivers. An experiment was conducted to study the influences of two interaction modes, traditional touch-based mobile phone interaction and gesture-based mobile phone interaction, on driving behavior in three different cognitive level task groups. The results indicate that gesture-based mobile phone interaction can improve driving performance with regard to lateral position-keeping ability and steering wheel control; nevertheless, it has no significant impact on longitudinal metrics such as driving speed, driving speed variation, and throttle control variation. Gesture-based mobile phone interactions have a larger effect on secondary tasks with medium cognitive load but not on actual operation tasks. It was also verified that the performance of gesture-based mobile phone interaction was better in secondary mobile phone tasks such as switching (e.g., switching songs) and adjusting (e.g., adjusting volume) than the traditional interaction mode. This study provides the theoretical and experimental support for human–computer interaction using gesture-based mobile phone interactive control in future automobiles.

EXPERIMENTAL STUDY OF THE IMPACT DAMAGE ON AN Al2O3-COATED GLASS UNDER STRESS

2006 ◽  
Vol 20 (25n27) ◽  
pp. 4529-4534 ◽  
Author(s):  
CHANG-MIN SUH ◽  
SUNG-HO KIM ◽  
DUCK-YOUNG SUH
Keyword(s):  
Compressive Stress ◽  
Impact Test ◽  
Impact Damage ◽  
Soda Lime ◽  
Target Distance ◽  
Soda Lime Glass ◽  
Optimum Conditions ◽  
Stereo Microscope ◽  
Steel Balls ◽  
The Impact

The impact damage of an Al 2 O 3-coated soda-lime glass under tensile and compressive stress conditions was investigated by an impact test using a steel ball (2mm dia.). The size of the glass specimens was 40×40×5( mm ). In order to change the porosity percent of each specimen, the target distance was set at 120mm and 70mm. Also, the effect of the thickness of the coating layer was shown by two amounts (100 μm and 50 μm). The velocity of the steel balls was set between 30 and 60m/s. After the impact test, the crack patterns and lengths were measured using a stereo-microscope. The tensile and compressive specimens were prepared by inflation and deflation of air pressure within a pressure vessel. It was confirmed that the crack length of the glass under tensile stress was longer than that of glass under compressive stress. Also, the optimum conditions were a target distance of 70mm and 100 μm of a coating thickness, thus resulting in a minimization of porosity percent and area.

CFD Analysis of the Twin Inclined Injection Flows in an Axi-Symmetric Duct along with Main Turbulent Flow

2014 ◽  
Vol 592-594 ◽  
pp. 1897-1902
Author(s):  
Debajit Saha ◽  
Snehamoy Majumder
Keyword(s):  
Turbulent Flows ◽  
Velocity Variation ◽  
Angle Variation ◽  
Bulk Fluid ◽  
Circular Duct ◽  
Injection Angle ◽  
Curvature Effects ◽  
Mass Injection ◽  
Secondary Injection ◽  
The Impact

A numerical simulation has been carried out to study the effects of twin inclined side mass injection with cross flow through a circular duct using modified model, considering streamline curvature effects by modifying the model constants. 1/7th turbulent velocity profile has been taken at the inlet. The effects of side mass injection on the flow pattern of the main bulk fluid and the mixing of two mutually cross turbulent flows have been studied in details. The formation of recirculatory flow has been visualized by varying the primary as well as secondary injection angle. With the variation of the injection angle axial velocity profiles at various locations and the centerline velocity variation along the duct have been studied. It has been observed that the impact of primary injection angle variation on the recirculation size is more than the secondary injection angle variation.

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