The Experts below are selected from a list of 27333 Experts worldwide ranked by ideXlab platform
Ole Arve Misund - One of the best experts on this subject based on the ideXlab platform.
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Underwater acoustics in marine fisheries and fisheries research
Reviews in Fish Biology and Fisheries, 1997Co-Authors: Ole Arve MisundAbstract:Underwater acoustics enables the detection and precise location of fish and is therefore a prerequisite for effective fishing methods such as pelagic trawling and purse seining. The application of acoustic instruments to detect fish and monitor Gear Performance in model commercial fisheries is outlined. The latest developments in obtaining information such as bottom roughness and determining such characteristics of fish detected as size and species are presented. \n\nEcho integration is now widely used to estimate the abundance of commercially important fish stocks. The principles of the method are outlined briefly, and special emphasis is put on such effects of fish behaviour as the dramatic influence of fish orientation on its backscattering cross section, the possible effects of vessel avoidance, and the uncertainties connected with spatial variability. \n\nThe use of acoustic tags, echosounders and sonar to study and quantify fish behaviour and distribution is outlined, with particular attention to new developments that provide detailed information on fish behaviour and distribution in relation to environmental parameters. \n\nFuture developments and improvements in the application of underwater acoustics to commercial fisheries and fisheries research are suggested. \n
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Underwater acoustics in marine fisheries and fisheries research
Reviews in Fish Biology and Fisheries, 1997Co-Authors: Ole Arve MisundAbstract:Underwater acoustics enables the detection and precise location of fish and is therefore a prerequisite for effective fishing methods such as pelagic trawling and purse seining. The application of acoustic instruments to detect fish and monitor Gear Performance in modern commercial fisheries is outlined. The latest developments in obtaining information such as bottom roughness and determining such characteristics of fish detected as size and species are presented.
Alain Bernard - One of the best experts on this subject based on the ideXlab platform.
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New methodology to reduce the transmission error of the spiral bevel Gears
CIRP Annals - Manufacturing Technology, 2014Co-Authors: Julien Astoul, J. M. Linares, Emmanuel Mermoz, M. Sartor, Alain BernardAbstract:New methods and tools have been developed the last years to improve the understanding of Gear meshing. Mechanical industries attach growing attention to the dynamic behavior of mechanical transmissions, including vibration and noise that result. The transmission error of the Gear, which measures the intensity of one of the main causes of dynamic phenomena, can be considered as a relevant indicator of Gear Performance. This paper presents a new design method of spiral bevel Gears, the objective of this method being to reduce their quasi-static transmission error. The proposed approach is based on an optimization process including loaded meshing simulations. The simulation model has been evaluated using a helicopter tail Gearbox as bench test. Measurement results are given, showing a good correlation with predictions. © 2014 CIRP.
Karsten Stahl - One of the best experts on this subject based on the ideXlab platform.
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Investigations into non-metallic inclusion crack area characteristics relevant for tooth root fracture damages of case carburised and shot-peened high strength Gears of different sizes made of high-quality steels
Forschung im Ingenieurwesen, 2019Co-Authors: D Fuchs, S Schurer, T. Tobie, Karsten StahlAbstract:Case carburised and shot-peened high-strength Gears can fail by tooth root bending failures in the very high cycle fatigue range of the S‑N-curve due to crack initiation at a non-metallic inclusion. It is essential to understand crack characteristics and mechanisms of such sub-surface initiated cracks, which are different to surface initiated cracks, in order to further increase the Gear Performance. This paper discusses the results of detailed analyses of such fractured surfaces. Einsatzgehärtete und kugelgestrahlte hochtragfähige Zahnräder können im Zahnfuß im Wöhlerlinienbereich sehr hoher Lastwechsel aufgrund einer Rissinitiierung an nicht-metallischen Einschlüssen ausfallen. Es ist wichtig, die Risseigenschaften und -mechanismen solcher unter der Oberfläche initiierten Risse zu verstehen, welche sich von oberflächeninitiierten Rissen unterscheiden, um die Zahnradleistung weiter zu erhöhen. In dieser wissenschaftlichen Veröffentlichung werden die Ergebnisse detaillierter Analysen solcher gebrochenen Oberflächen behandelt.
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investigations into non metallic inclusion crack area characteristics relevant for tooth root fracture damages of case carburised and shot peened high strength Gears of different sizes made of high quality steels
Forschung Im Ingenieurwesen-engineering Research, 2019Co-Authors: D Fuchs, Thomas Tobie, S Schurer, Karsten StahlAbstract:Case carburised and shot-peened high-strength Gears can fail by tooth root bending failures in the very high cycle fatigue range of the S‑N-curve due to crack initiation at a non-metallic inclusion. It is essential to understand crack characteristics and mechanisms of such sub-surface initiated cracks, which are different to surface initiated cracks, in order to further increase the Gear Performance. This paper discusses the results of detailed analyses of such fractured surfaces.
R. Gnanamoorthy - One of the best experts on this subject based on the ideXlab platform.
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Transmission efficiency of polyamide nanocomposite spur Gears
Materials & Design, 2012Co-Authors: S Kirupasankar, C Gurunathan, R. GnanamoorthyAbstract:Abstract Gears made of polymer and its composites find increasing application due to their superior properties. This paper reports the transmission efficiency of pristine polyamide 6 (PA6) and clay incorporated polyamide nanocomposite (PNC) spur Gears. Numerical studies were conducted to predict the frictional and hysteresis power loss. A power absorption type Gear test rig, developed in-house, was used to determine the power loss during transmission. The effect of applied torque on the transmission efficiency of PA6 and PNC spur Gears are reported. Addition of nanoclay particles improves the stiffness and suppresses the viscoelastic nature of polyamide 6. The increase in Gear tooth temperature due to hysteresis and friction, significantly affects the tooth shape, and thereby, the Gear Performance. The enhancement in mechanical properties of polyamide nanocomposite Gears results in higher power transmission efficiency compared to pristine polyamide Gear.
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Heat generation in Fe-C-Cu-MoS2-sintered spur Gears under unlubricated conditions:
Proceedings of the Institution of Mechanical Engineers Part J: Journal of Engineering Tribology, 2007Co-Authors: S. Dhanasekaran, R. GnanamoorthyAbstract:AbstractIn many applications, Gears operate under unlubricated conditions and there is a need for new materials with a good friction and wear characteristics for use in these situations. A new alloy, Fe-C-Cu + MoS2, was developed using a powder metallurgy processing route for Gear and bearing running under unlubricated operating conditions. Spur Gears were compacted from the pre-alloyed powders and sintered. The Gear Performance was evaluated using a power absorption type Gear test rig. The temperature rise measured during testing depends on the material composition, porosity, and coefficient of friction. A thin lubricant film formed in the MoS2-added Gears affects the friction and thereby the heat generation during running. An optimum amount of MoS2 addition, 3 per cent, is found beneficial in reducing the surface temperature rise. The analytical model predicts the temperature rise with a reasonable accuracy.
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effect of Gear tooth fillet radius on the Performance of injection molded nylon 6 6 Gears
Materials & Design, 2006Co-Authors: Sambandam Senthilvelan, R. GnanamoorthyAbstract:Abstract In metal Gears the Gear manufacturing process and cutting tool dimensions decide the Gear tooth geometry and affect the Gear Performance. In polymer base Gears, injection molding process permits development of Gears with any tooth geometry economically. In this paper, the effect of Gear tooth fillet radius on the Performance of injection molded Nylon 6/6 Gear made with different tooth fillet radius 0.25 and 0.75 mm is reported. Finite element analysis carried out indicates high fillet root stresses and Gear tooth deflection in Gears with low fillet radius. Gear Performance was evaluated using a power absorption type Gear test rig. Repeated Gear tooth loading during service causes a rise in the Gear temperature which is due to hysteresis effects and friction. The temperature rise depends on the fillet radius. At low applied loads, Gears with less fillet radius fail by crack initiation at the root region due to increased stress concentration whereas Gears with large fillet radius fail by micro cracking at the pitch region.
Michael Breen - One of the best experts on this subject based on the ideXlab platform.
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Gear Performance and catch comparison trials between a single trawl and a twin rigged Gear
Fisheries Research, 1998Co-Authors: G.i. Sangster, Michael BreenAbstract:The fishing and engineering Performance of single and twin rigged scraper trawls were compared during trials aboard a commercial fishing boat. These trawls had differences both in Performance and in mean catch. There were three major differences in the geometry of the two Gears (door spread, wing spread and bridle angle) and thus the area of seabed effectively fished by each. This investigation attempted to assess whether these differences in Performance parameters can account for the observed differences in mean catch for each species. The twin trawl significantly out-fished the single trawl for haddock (Melanogrammus aeglefinus) (22%), flatfish (plaice (Pleuronectes platessa) and lemon sole (Microstomas kit)) (67%), anglerfish (Lophius piscatorius) (120%), Nephrops (Nephrops norvegicus) (421%) and by-catch (22%). The increased catch of haddock and by-catch appeared to be simply a function of the area effectively fished by the two Gears. However, even over the same swept area the twin trawl was still more effective at catching anglerfish (81%), flatfish (40%) and Nephrops (340%). Analysis of bridle herding efficiency demonstrated that anglerfish and flatfish may have been herded more effectively by the twin trawl bridles, which had the smaller angle of attack. No definite explanation can be provided for the greatly increased Nephrops catch in the twin rigged trawl. However, it is suggested that differences in ground Gear shape for the two Gears could imply different ground Gear contact, and hence different fishing efficiencies for ground living species such as Nephrops. There was no evidence of diurnal variation within the Nephrops catch.
