Gear Effect Research Articles

Directorial Style for Interactive Storytelling and the Fallacy of Ownership: The Case of Resident Evil 7

This article discusses some of the issues affecting storytelling in an immersive and interactive medium such as Virtual Reality. Interactive works which reconfigure their images as three-dimensional environments bearing affordances seems able to convey a proper sense of “spatial presence” – that is, the perceptive and cognitive illusion of being physically immersed in a digital environment, rather than in the material one which actually surrounds the body. However, I will show that VR technology is doomed to produce “breaks in presence”: moments which rise awareness of the mediated nature of the experience, shattering the illusion of presence, and which represent undesirable side-effects for the aesthetics of immersion generally promoted by VR works. In order to do so, I will use the VR game Resident Evil 7 as a case study. First, I will analyse the sophisticated formal solutions employed by the game to create a terrifying illusion of presence, highlighting their connection with cinematic strategies common to the horror genre; then, I will focus on sections of the interactive experience which nonetheless devaluate the effects of these stylistic gears by bringing consciousness about the impalpable and disembodied nature of the virtual body during the (simulated) physical interaction with the environment.

The Effects of Firefighter Equipment and Gear on the Static and Dynamic Postural Stability of Fire Cadets.

Slips, trips, falls, and jumps were the second leading cause of injuries at the fireground. The purpose of this study was to explore the effects of firefighter equipment and gear (EQG) on postural stability and determine if load per kg of body mass (L/BM) is associated with postural stability. 26 male fire cadets (26.15 ± 4.16 yr., 178.92 ± 6.92 cm, 86.61 ± 9.09 kg) were included in the analyses. Participants performed 3 single-leg landings (SLL) with and without EQG. The first 3 seconds of ground reaction forces following initial ground contact were used to calculate dynamic postural stability index (DPSI). Participants completed 2 static balance tasks (normal stability and limits of stability (LoS)) with and without EQG. Main outcome measures were overall LoS score (LoSS), direction-specific LoSS, and LoS distance (cm) of COP excursion (LoSD) in the anterior, posterior, right, and left directions. Separate paired-samples t-tests were run to determine the differences between load conditions for DPSI, overall LoSS, direction-specific LoSS, and LoSD in all directions. Bivariate correlations were conducted to determine the relationship of L/BM to DPSI, overall LoSS, and LoSS and LoSD in the anterior, posterior, right and left directions. Due to the use of multiple statistical tests, a Bonferroni correction was used, and the alpha level of .05 was adjusted to .005. DPSI was significantly higher loaded than unloaded, t(25) = -13.965, p < .001, d = 7.032, 95% CI, -0.133 to -0.099. No other comparisons were significant. A significant strong positive correlation (r(24) = .665, p < .001) was observed between L/BM and DPSI. No other correlations were significant. This study demonstrates that firefighter EQG may significantly impact a cadet's ability to maintain postural stability while performing their duties.

Analysis of Magnetic Gearing Effect in Field-Modulated Transverse Flux Linear Generator for Direct Drive Wave Energy Conversion

Direct drive wave energy conversion (DD-WEC) is a typical low-speed long-stroke application. Harvesting wave energy presents enormous challenges, because wave energy naturally exists in the form of extremely low speed, high force, or torque motion. However, the frequency of flux linkage in field-modulated machine can be increased by the magnetic gear effect, and the output voltage and power density can also be effectively enhanced. In this article, based on the field-modulated principle, a field-modulated transverse flux linear generator (FM-TFLG) is proposed. Different combinations of permanent magnet (PM) number, slot number, and translator number are selected and their performances are compared and analyzed. Results show that the electric frequency is enhanced as the modulation ratio increases. Compared with 18/12/17 (PM number/slot number/translator number) topology, 12/12/11 FM-TFLG has advantages of lower thrust ripple and total harmonic distortion (THD) of back electromotive force (EMF), higher thrust/power density, and efficiency. The proposed 12/12/11 FM-TFLG is a good candidate for DD-WEC.

Lubrication Performance of Helical Gear Pair Under Dynamic Load Based on Local Involute Profile

Abstract The tribological properties of gear interface have been widely concerned in the past decades. In this study, based on the local involute profile and crown modification, a thermal elastohydrodynamic lubrication model is proposed for a helical gear pair. To discuss the influences of dynamic load on the tribological properties of helical gear pair, the dynamic mesh force of tooth surface is obtained by torsional vibration model. The influences of working conditions and surface roughness on the tribological properties of helical gear pair are investigated. The tribological properties are evaluated in terms of the average film thickness, friction coefficient, mechanical power loss etc. Results show that the dynamic effect of gears has a significant effect on the tribological properties, especially at a specific speed, such as resonance speed. In order to simulate gear lubrication accurately, it is recommended to adopt local involute tooth profile and consider tooth profile modification to calculate geometric clearance. The influence of input rotation speed on the dynamic characteristics and tribological properties of gear is more significant than that of input torque. The surface roughness significantly changes the distribution of interface pressure and film thickness. With the increase of roughness amplitude, the local fluctuation amplitude of pressure and film thickness increase and the dry contact occurs at the end of contact line. Meanwhile, the maximum subsurface stress moves toward the tooth surface, especial for the high frequency engineering roughness. This local stress concentration is harmful to the fatigue life of gear meshing process.

Impact of bottom trawling on sediment biogeochemistry: a modelling approach

Abstract. Bottom trawling in shelf seas can occur more than 10 times per year for a given location. This affects the benthic metabolism, through a mortality of the macrofauna, resuspension of organic matter from the sediment, and alterations of the physical sediment structure. However, the trawling impacts on organic carbon mineralization and associated processes are not well known. Using a modelling approach, the effects of increasing trawling frequencies on early diagenesis were studied in five different sedimentary environments, simulating the effects of a deeper-penetrating gear (e.g. a tickler chain beam trawl) versus a shallower, more variable penetrating gear (e.g. an electric pulse trawl). Trawling events strongly increased oxygen and nitrate concentrations in surface sediment layers and led to significantly lower amounts of ammonium (43 %–99 % reduction) and organic carbon in the top 10 cm of the sediment (62 %–96 % reduction). As a result, total mineralization rates in the sediment were decreased by up to 28 %. The effect on different mineralization processes differed both between sediment types and between trawling frequencies. The shallow-penetrating gear had a slightly smaller effect on benthic denitrification than the deeper-penetrating gear, but there were no statistically different results between gear types for all other parameters. Denitrification was reduced by 69 % in a fine sandy sediment, whereas nitrogen removal nearly doubled in a highly eutrophic mud. This suggests that even relatively low penetration depths from bottom fishing gears generate significant biogeochemical alterations. Physical organic carbon removal through trawl-induced resuspension of sediments, exacerbated by a removal of bioturbating macrofauna, was identified as the main cause of the changes in the mineralization process.

Design and Analysis of Hybrid-Excited Flux Modulated Linear Machines With Zero-Sequence Current Excitation

This article investigates a hybrid-excited flux modulated linear machine (HEFMLM) with zero-sequence current excitation. With the adoption of integrated open winding, zero-sequence current can be utilized to provide the dc excitation and further improve the thrust force density. First, the machine topology, drive circuit, and operation principle are described. Then, the magnetomotive force (MMF)-permeance model is built to analytically calculate the air-gap hybrid-excited field harmonics and further verified by finite element (FE) analysis. Moreover, the electromagnetic performances including open circuit characteristics, flux regulation capability, thrust force characteristics, and demagnetization risk are comparatively studied. Due to the improved exciting field and armature MMFs with integrated winding, the thrust force capability can be significantly enhanced by 22.6% on the premise of rated copper loss. Besides, the proposed HEFMLM exhibits high thrust force density compared with the other three types of HEFMLM, benefitting from a high pole-pair number of permanent magnets (PMs) along with a more obvious magnetic gearing effect. Finally, a prototype of the HEFMLM is carried out for experimental validation.

Effect of metal and polymer mating gears on the bending fatigue performance of asymmetric polymer gears

The material of the mating gear influences the fatigue life of polymer gears. The bending fatigue characteristics of polyamide 66 asymmetric gears (34°/20° and 20°/34°) corresponding to steel–polymer and polymer–polymer material combinations were investigated. The performance of symmetric gear pairs (20°/20°) was determined to serve as a comparison. Quasi-static numerical simulations were performed in a finite element analysis tool to predict root bending stress, load sharing ratio, and tooth deflection. The bending fatigue strength of steel–polymer and polymer–polymer pairs of each test configuration was determined using bending fatigue tests. The load sharing ratio and root bending stress of polymer–polymer pairs decreased substantially compared to steel–polymer pairs. The extent of deflection-induced load sharing was greater in polymer–polymer pairs. The bending fatigue life of polymer–polymer pairs was lower than that of steel–polymer pairs owing to the higher operating temperature. In polymer–polymer pairs, polymer driving and driven gears increased the heat generated and diminished the heat dissipation to the environment. In steel–polymer and polymer–polymer pairs, the configuration with the highest bending fatigue strength was 34°/20° and 20°/34°, respectively. This divergence was caused by the increase in temperature difference between the two configurations for polymer–polymer pairs. Analysis of hysteresis loops indicated that the loop area was higher for polymer–polymer pairs, signifying the increased amount of dissipated energy. No noticeable variation was observed between the failure modes of steel–polymer and polymer–polymer pairs despite the significant difference in the operating temperatures. The bending stress and operating temperature were the dominant factors affecting the performance of steel–polymer and polymer–polymer gear pairs, respectively.

Planetary Gearbox Dynamic Modeling Considering Bearing Clearance and Sun Gear Tooth Crack.

Planetary gearbox systems are critical mechanical components in heavy machinery such as wind turbines. They may suffer from various failure modes, due to the harsh working environment. Dynamic modeling is a useful method to support early fault detection for enhancing reliability and reducing maintenance costs. However, reported studies have not considered the sun gear tooth crack and bearing clearance simultaneously to analyze their combined effect on vibration characteristics of planetary gearboxes. In this paper, a dynamic model is developed for planetary gearboxes considering the clearance of planet gear, sun gear, and carrier bearings, as well as sun gear tooth crack levels. Bearing forces are calculated considering bearing clearance, and the dynamic model equations are updated accordingly. The results reveal that the combination of bearing clearances can affect the vibration response with sun gear tooth crack by increasing the kurtosis. It is found that the effect of planet gear bearing clearance is very small, while the sun gear and carrier bearing clearance has clear impact on the vibration responses. These findings suggest that the incorporation of bearing clearance is important for planetary gearbox dynamic modeling.

Highest risk abandoned, lost and discarded fishing gear

Derelict abandoned, lost and discarded fishing gear have profound adverse effects. We assessed gear-specific relative risks from derelict gear to rank-order fishing methods based on: derelict gear production rates, gear quantity indicators of catch weight and fishing grounds area, and adverse consequences from derelict gear. The latter accounted for ghost fishing, transfer of microplastics and toxins into food webs, spread of invasive alien species and harmful microalgae, habitat degradation, obstruction of navigation and in-use fishing gear, and coastal socioeconomic impacts. Globally, mitigating highest risk derelict gear from gillnet, tuna purse seine with fish aggregating devices, and bottom trawl fisheries achieves maximum conservation gains. Locally, adopting controls following a sequential mitigation hierarchy and implementing effective monitoring, surveillance and enforcement systems are needed to curb derelict gear from these most problematic fisheries. Primary and synthesis research are priorities to improve future risk assessments, produce the first robust estimate of global derelict gear quantity, and assess the performance of initiatives to manage derelict gear. Findings from this first quantitative estimate of gear-specific relative risks from derelict gear guide the allocation of resources to achieve the largest improvements from mitigating adverse effects of derelict gear from the world’s 4.6 million fishing vessels.

Evaluation of Linear Permanent Magnet Vernier Machine Topologies for Wave Energy Converters

Today, the importance of using vernier machines in wave energy converters has increased because of its simple structure and ability to generate a lot of thrust force at low speeds due to the magnetic gear effect. The linear vernier permanent magnet machine has been designed in various structures. Proper design and selection of the main parameters of the machine will improve performance and increase the efficiency of the linear vernier machine. One of these parameters is the shape of the permanent magnets and how they are magnetically oriented. The novelty of this paper is the reduction of leakage flux, achieved by changing the shape and orientation of the permanent magnet. Three types of linear permanent magnet vernier machines with different permanent magnet structures and orientation, including V-shape, Halbach array and consequent-pole are presented. The considered machines have been compared to each other and to the existing machine in terms of airgap flux density, back EMF, PM flux, Inductance, thrust force, detent force, loss, efficiency, power factor, flux density and flux line, using the finite element method in the same conditions and with the same volume of permanent magnets. The results show that the magnetic orientation and shape of the permanent magnet have a considerable effect on the leakage flux, and all the proposed models have a lower leakage flux and better performance compared to the existing model.

CFD-based calculation method of convective heat transfer coefficient of spiral bevel gear in intermediate gearbox under splash lubrication

Purpose This paper aims to propose a numerical method to calculate the convective heat transfer coefficient of spiral bevel gears under the condition of splash lubrication and to reveal the lubrication and temperature characteristics between the gears and the oil-air two-phase flow. Design/methodology/approach Based on computational fluid dynamics, the multiple reference frames (MRF) method was used to simulate the rotational characteristics of gears and the motions of their surrounding fluid. The lubrication and temperature characteristics of gears were studied by combining the MRF method with the volume of the fluid multiphase flow model. Findings The convective heat transfer coefficient can be improved by increasing the rotational speed and the oil immersion depth. Moreover, the temperature of the tooth surface having a large convective heat transfer coefficient is also found to be low. A large convection heat transfer coefficient could lead to a good cooling effect. Originality/value This method can be used to obtain the convective heat transfer coefficient values at different meshing positions, different radii and different tooth surface positions. It also can provide research methods for improving the cooling effect of gears under the condition of splash lubrication. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-07-2020-0233/

Dynamic contact behavior of asymmetric spur gear

Abstract There is a growing demand for superior performing gear drives which can bear huge loads and has better endurance at high speed. Also, these gear pair should cost less and have a longer life of operation. There are some applications like automobile drive train, Aero-Engine, wind turbines where the loading on the gear drive is uni-directional. This gives the designers to freely look into non-standard gear design, where the drive side of the the gear needs not be symmetric when compared with the coast side. This led to developing of Asymmetric gear teeth. This work assesses in depth the dynamic contact behaviors of an involute asymmetric gear pair. The effect of the pressure angle change on the drive side is analyzed. Matlab was used to generate the gear teeth. This research gave an insight for evaluating the dynamic gear contact and predicting the dynamic loads occurring on gear tooth, which helps to optimize gear parameter design and to understand the complex gear meshing effect phenomenon. Dynamic analysis of spur gear pairs was solved numerically using LS-DYNA. The spur gear pair's dynamic fillet stress was correlated with an experimental result. The simulation results indicate that the stress distribution of the gear surface is governed by alteration of the tooth pressure angle. The current solution by the finite element application is intended to be implemented in gear dynamics for better understanding of the transient behavior and its harmonics.

Performance Improvement of Dual Stator Axial Flux Spoke Type Permanent Magnet Vernier Machine

This paper presents performance improvement of dual stator axial-flux spoke type permanent magnet vernier machine (DSAFST-PMVM), which has the capability to generate high torque at a lower speed due to magnetic gearing effect. Flux focusing effect is created by means of dual stator single rotor topology with spoke type permanent magnets. It is best suitable for high-performance industrial applications such as servo motors, robot arms, wind power, electric vehicles, and elevator applications. A PM shape is proposed in this paper which has notches in such a way that it produces discrete skew effect which reduces the cogging torque and torque ripples. Optimization of magnet shape is done to make the optimized model more competitive than the proposed and basic models. Main parameters such as back emf, cogging torque, torque ripples, electromagnetic torque, VTHD, airgap flux densities, flux density distribution, power factor, and power of the machine are compared among the basic model, proposed model, and optimized models. The comparative analysis is done by using the time stepped 3D finite element method.

Fault feature analysis of planetary gear set influenced by cracked gear tooth and pass effect of the planet gears

Based on the loaded tooth contact analysis method, the time-varying mesh stiffness of planetary gear set considering gear crack fault are calculated. The real crack path of gear tooth is simulated based on the fracture mechanics theory. Meanwhile, an improved lumped parameter dynamic model is also established, which can effectively consider the time-varying distance between the planet gear and the transducer mounted on the fixed ring gear. The correctness of the proposed dynamic model is verified with the simulation results in literatures and also the experimental result on a planetary gear test rig. The amplitude modulations phenomenon and the frequency modulation phenomenon can be clearly observed in the simulated results. Using the proposed dynamic model, the fluctuation of the dynamic load sharing factors which considering the crack faults of gears are revealed, the result shows that the ring gear crack fault can rarely affect the dynamic load sharing among the external meshing gear pairs. The analysis in this study can help better understand the internal laws of crack fault for planetary gear set.

Analysis of a New Partitioned-Primary Flux-Reversal Hybrid-Excited Linear Motor

A new partitioned-primary flux-reversal hybrid-excited linear motor is proposed and investigated in this article, which features an asymmetrical double-sided primary structure. The novelty of this motor lies in the adoption of a partitioned-primary structure by moving the field excitation winding to an additional primary, thus it benefits from improved space utilization ratio since both armature and field windings can be separately mounted. First, the topology, feasible slot/pole combinations, and operating principles of the proposed machine are introduced. The magnetic flux density distributions in two air-gap regions are comparatively studied from the perspective of magnetic gearing effect. Then, global optimization of the proposed motor with different slot/pole combinations is performed to maximize both the output thrust force and flux-adjusting range based on 2-D finite-element analysis (FEA). In addition, the electromagnetic performance of the motors including flux-adjusting capability, thrust force, detent force, and force ripple with different slot/pole combinations are comparatively investigated. Finally, a 6-slot/7-pole prototype is manufactured and tested to verify the FEA and calculations. It is shown that the proposed motor, benefiting from a partitioned-primary topology, exhibits very good flux-adjusting capability and overloading capacity. Thus, it has good prospect in applications that require flexible speed control.

The influence of 5-iron clubhead mass distribution on clubhead presentation and initial ball launch conditions: Part I: Golf robot tests

It is well accepted that iron clubhead properties affect shot outcomes in golf. However, the mechanisms that contribute to this relationship have not received recent scientific study. The purpose of this study was to determine how the different clubhead mass distributions in a blade 5-iron and a cavity-back 5-iron affect clubhead presentation and ball launch conditions. Nine clubhead presentation variables and four ball launch variables were measured for ten discrete impact locations and five face angles during swings using a golf robot. Group means were analysed statistically using an independent samples approach to identify differences and linear regression was used to indicate relationships between key launch variables. The cavity-back showed higher effective clubhead loft with greater total ball spin than the blade, despite having matched static lofts, whilst also providing more consistent launch outcomes across a range of impact locations. Evidence of the phenomenon known as the ‘gear effect’ was found for the cavity-back, but not the blade, suggesting that the threshold at which the clubhead’s centre of gravity (CG) is deep enough to detect the gear effect lies between the CGs of the two 5-iron types. These novel robot test findings lend support to the perceived performance benefits of perimeter-weighted irons; whether these effects translate to human golfer swings is reported in Part II of this paper.

Synthesis of a Flux Modulation Machine With Permanent Magnets on Both Stator and Rotor

Flux modulation permanent-magnet machines (FMPMs) operate on the magnetic gearing effect and thus can produce large torque at low rotation speed. However, the most significant drawback of many FMPMs is the low power factor. In order to further improve the torque density and power factor, this article proposes an advanced FMPM with permanent magnets (PMs) on both stator and rotor. In this article, the configuration and operation principle of the proposed machine will be introduced. Moreover, this article will also investigate the torque and power factor performances of the proposed machine under different rotor slot numbers. Then, to verify the superiority of the proposed FMPM, it is compared with a regular stator-PM FMPM and a regular rotor-PM FMPM in terms of cogging torque, back-electromagnetic force, rated torque, torque ripple, power factor, overload capability, flux weakening capability, and efficiency. Finally, a prototype of the proposed FMPM is tested, and the experimental results have verified the theoretical analyses.

Electromagnetic Performance Analysis and Experimental Verification Considering the End Effect of Linear Magnetic Gears Using Subdomain-Based Analytical Method

This study analyzes and verifies the electromagnetic performance and thrust characteristics of linear magnetic gears using the subdomain-based analytical methods. By simplifying the analytical model, the governing equations of each domain are calculated based on the Maxwell equation. In addition, the undetermined coefficients of the governing equations are derived using four boundary conditions. In magnetic gears, where power transmission is important, the force characteristics are also important. The force characteristics were calculated using the undetermined coefficients and the Maxwell stress tensor.

An integrated methodology for assessing ecological and economic impacts for marine management: A case study for abrasion and mobile fishing gear effects

Ensuring a balance of conservation and human activities within the marine environment requires complex decisions on how to achieve conservation objectives whilst considering the likely economic and social costs and benefits of such decisions. We assessed the risk of adverse effects from abrasion caused by bottom fishing, as a case study, to demonstrate an integrated spatial management methodology. Risk was quantified in the Galway Bay, Ireland region using a 1 km grid, as the ratio between mortality and recovery of benthic infauna exposed to abrasion effects estimated from fishing data. Risk was considered high if annual mortality exceeded recovery. A Bayesian network model, incorporating ecological and economic data, compared three management scenarios: i) business as usual (BAU), ii) exclusion of fishing vessels over 18 m within 6 nautical miles (68% of study area) (Length) and iii) a network of marine protected areas (MPAs) closed to all fishing vessels (11% of study area) (MPA). The BAU scenario indicated that risk was high for 85.6% of the study area. The length scenario resulted in a 14.6% reduction in high risk cells, affecting €0.9 M of landings, €0.7 M of indirect output and 19 full time equivalent (FTE) employees. The MPA scenario resulted in a 1.7% reduction of high risk cells. This scenario affected €0.17M in landings, €0.13M in indirect outputs and 3 FTE employees. We present a method which provides a quantitative, spatial, risk and economic impact assessment of the effects of human activities and pressures on the marine environment that assesses potential costs and benefits of management options to mitigate against these pressures. Future development of a mortality-recovery ratio for defined time periods would enable application across multiple habitats, human activities and pressures.

Electromagnetic performance analysis of linear vernier machine with PM and HTS-Bulk

Today, superconductor materials are widely used in electric machines because of their unique properties. This has been always a question for designers and researchers whether super-conductors can be a good substitute for Permanent Magnet (PM) or not. In this paper, the performance of a dual stator linear vernier machine under identical conditions in the presence of High-Temperature Superconductor Bulk (HTS-Bulk) and PM are analyzed and compared. HTS-Bulk and PM are located between the slot of the stator to illustrate the advantages and disadvantages of the superconductor. The performance of both machines is based on the magnetic gear effect which due to the existence of numerous magnetic pole pairs is able to generate relatively high thrust force at very low speed. The main parameters of both machines such as: air gap flux density, PM flux, back-EMF, self-inductance, mutual-inductance, power factor, detent force and thrust force have been compared to each other at the same geometry by finite element method.