131,620 research outputs found
Industrial Winch System, Tampa, D
No full textA close-up of an industrial winch system, showcasing its worn cables and metal casing. The equipment appears heavily used, with visible signs of wear and rust.https://digitalcommons.usf.edu/gandy_commercial/3088/thumbnail.jp
Numeric simulation of glider winch launches
No full textA numeric simulation tool for simulating the winch launch of gliders has been realized and employed for a number of analyses. It comprises models of aircraft, pilot, winch, winch operator, cable, atmosphere and terrain. Results are in agreement with pilots' experience. The simulation framework is implemented in Matlab/Simulink. It is based on an existing flight dynamics simulation used e.g. to assess the application of actuators in sailplanes. Configuration has been kept fairly generic to allow modeling of different aircraft, winches, cables and conditions. A GUI allows easy change of parameters. The cable may be modeled either as a simple secant between winch and aircraft, where force variations along the cable are neglected. The alternative is a FEM representation with the cable separated into massless cylinder elements connecting mass points. This allows including aerodynamic forces acting on the cylinders and gravity acting on the mass points. The cylinders may also be assigned spring and damping constants to model elasticity effects. Finally, they also interact with the terrain. For the winch, an automotive drive train model was employed. The rotating parts act as a flywheel whose acceleration is determined by power input from the engine and power drain from the cable. Ground interaction is modeled for a set of discrete contact points including wheels, exposed structure elements like skids or wingtips and the cable elements. Each contact point has spring and damping constants to model the force normal to the terrain. Forces in the contact plane are calculated via friction coefficients. The humans in the loop are approximated by simple control elements, namely PID controllers. The winch operator controls the cable force at the winch using engine throttle. The glider pilot model is divided into three submodels controlling elevator, aileron and rudder. The elevator channel is responsible for airspeed, while bank angle (and thus heading rate) is controlled by aileron deflection. The objective of the rudder channel finally is to minimize the angle of sideslip. All pilot controller gains are scheduled by dynamic pressure. Human factors are included in terms of reaction time and neuromuscular delay. Analyses were carried out varying different simulation parameters like cable type, cable force, hook position, pilot behavior and wind influence. Results will be presented in the paper
Numeric simulation of glider winch launches
No full textA numeric simulation tool for simulating the winch launch of gliders has been realized and employed for a number of analyses. It comprises models of aircraft, pilot, winch, winch operator, cable, atmosphere and terrain. Results are in agreement with pilots' experience. The simulation framework is implemented in Matlab/Simulink. It is based on an existing flight dynamics simulation used e.g. to assess the application of actuators in sailplanes. Configuration has been kept fairly generic to allow modeling of different aircraft, winches, cables and conditions. A GUI allows easy change of parameters. The cable may be modeled either as a simple secant between winch and aircraft, where force variations along the cable are neglected. The alternative is a FEM representation with the cable separated into massless cylinder elements connecting mass points. This allows including aerodynamic forces acting on the cylinders and gravity acting on the mass points. The cylinders may also be assigned spring and damping constants to model elasticity effects. Finally, they also interact with the terrain. For the winch, an automotive drive train model was employed. The rotating parts act as a flywheel whose acceleration is determined by power input from the engine and power drain from the cable. Ground interaction is modeled for a set of discrete contact points including wheels, exposed structure elements like skids or wingtips and the cable elements. Each contact point has spring and damping constants to model the force normal to the terrain. Forces in the contact plane are calculated via friction coefficients. The humans in the loop are approximated by simple control elements, namely PID controllers. The winch operator controls the cable force at the winch using engine throttle. The glider pilot model is divided into three submodels controlling elevator, aileron and rudder. The elevator channel is responsible for airspeed, while bank angle (and thus heading rate) is controlled by aileron deflection. The objective of the rudder channel finally is to minimize the angle of sideslip. All pilot controller gains are scheduled by dynamic pressure. Human factors are included in terms of reaction time and neuromuscular delay. Analyses were carried out varying different simulation parameters like cable type, cable force, hook position, pilot behavior and wind influence. Results will be presented in the paper
Drivers and dynamic processes for SMEs going global
No full textPurpose - Many, if not most, small to medium-sized enterprises (SMEs) are subject to the impacts of globalisation. This article seeks to explore the extra dimension of challenge to their already difficult environments when they have to venture into the world-trade system. Design/methodology/approach - Recent research undertaken separately by Polish, Italian, Norwegian and UK collaborators examined eight case studies of disparate smaller companies with international operations. This article brings together the common features found, and discusses them in terms of structural drivers and dynamic implications. Findings - Research findings include the stretching of capabilities in supporting customers in unfamiliar markets, the internal competition for funds in pursuing multiple international markets, the importance of word-of-mouth marketing, and the pressures on R&D functions. Practical implications - The critical importance of balance in smaller enterprises where resources are likely to be tightly constrained is highlighted, and the article observes that, while some of the challenges apply to many firms and other contexts, they are especially critical in SMEs. Originality/value - This article identifies common pressures and challenges facing SMEs when going global, and uses causal loop diagramming to capture the drivers and consider longer-term dynamic implications. © Emerald Group Publishing Limited
Cable tensile forces associated to winch design in tethered harvesting operations: A case study from the pacific north west
No full textCable tensile forces in winch-assist harvesting have been investigated in order to assess the safety concerns of the technology. However, the literature is lacking, particularly in regards to the impact of winch design. In this study, a Summit Winch Assist tethering a feller-director on ground slopes up to 77% was monitored for four days. The cable tensile forces were simultaneously recorded at the harvesting and anchor machine at a frequency of 100 Hz. Cameras and GNSS devices enabled a time study of the operations and the recording of machine positions. Winch functionality and design were disclosed by the manufacturer and used for the interpretation of the results. The cable tensile forces reached 296 kN at the harvesting machine and 260 kN at the anchor machine. The slow negotiation of obstacles while moving downhill recorded the highest peaks, mainly due to threshold settings of the winch in the brake system activation. Lower but significant peaks were also recorded during stationary work tasks. The peaks, however, were limited to a few events and never exceeded the endurance limit of the cable. Overall, the study confirmed recent findings in cable tensile force analysis of active winch-assist operations and provided evidence of the underlaying mechanisms that contribute to cable tensile forces
Assessment of cable tensile forces in active winch-assist harvesting using an anchor machine configuration
No full textThe growing interest in accessing steep terrain is pushing the expansion of the operating range of ground-based machines through winch-assist technology. However, cable tensile forces remain a major concern in the advancement of this technology. In this study, cable tensile forces in a winch-assist harvesting operation based on an anchor machine configuration were investigated. A harvesting machine tethered on ground slopes of up to 103% (45.9°) was observed over four days. Cable tensile forces were recorded at both the harvesting and anchor machines, at a frequency of 100 and 10 Hz, respectively. Cameras and GNSS devices enabled the execution of a time and motion study and the recording of machine positions. At the harvesting machine, peak tensile forces of up to 400 kN were recorded. Downhill movements of the harvesting machine were the cause of the highest peaks which, however, never exceeded the endurance limit of the cable. Numerous local variations in cable tensile forces exceeded 50 kN for just a few hundredths of a second, with a maximum variation of 300 kN in less than a second. Movements of the harvesting machine were the main cause of the major local variations. Depending on work element and harvesting machine movements, cable tensile forces were higher at either the harvesting or anchor machines; however, the highest peak tensile forces per work element and the related working loads were always recorded at the harvesting machine. Some implementation steps for improving the safety of winch-assist harvesting operations using anchor machines are also discussed
Design and Simulation of Emulsion Winch Based on Virtual Prototype
No full textAiming at the actual requirement of hauling hydraulic support along coalface, this paper presents a novel hydraulic winch powered by emulsion and detailedly designs mechanical transmission system and hydraulic control system. Based on virtual prototype, the 3-D model of the designed emulsion winch is built by Pro/E software, and interference simulation is carried out. In order to prove strength requirement of key component, the drum is analyzed by means of finite element analysis method and ANSYS software, and the maximum stress is obtained which less than the allowable stress. All this provides theoretical basis for the optimal design of emulsion winch.</jats:p
Chenopodium glaucum
No full text9. C. glaucum. Oak-leaved Goosefoot. Sm.Eng. Fl.ii. 14;Erg. Bot.1454;With.ii. 370. By road sides near Ponteland, at Chirton, and on St. Anthon's ballast-hills, N. Near Darlington, D. - Mr. E. Robson. On Sunderland ballast-hills, D. - W. Weighell's Herb.Published as part of Nathaniel John Winch, 1838, Flora of Northumberland and Durham, pp. 16-17 in Transactions of the Natural History Society of Northumberland, Durham, and Newcastle-upon-Tyne, Newcastle :Emerson Charnley, and Longman & Co. on pages 16-1
Chenopodium botryodes
No full text4. C. botryodes. Many spiked Goosefoot. Sm.Eng. Fl.ii. 11;Eng. Bot.2247;Hook.Br. Fl.138. On Sunderland ballast-hills, D W. Weighell's Herb.Published as part of Nathaniel John Winch, 1838, Flora of Northumberland and Durham, pp. 16-17 in Transactions of the Natural History Society of Northumberland, Durham, and Newcastle-upon-Tyne, Newcastle :Emerson Charnley, and Longman & Co. on pages 16-1
An investigation of Japanese educational cultural impact on Japanese language learning in an international context
No full textprovided qualitative data. There was no statistically significant difference between the two teaching methods regarding attainment in the two assignments. However, Japanisation was associated with significantly improved results in the Reading and Writing Test, compared with CLT. These results seem to suggest that embedding elements of Japanisation and Japanese educational culture into the teaching of Japanese to non-Japanese speakers in British language classrooms might possibly enhance students’ learning of reading and writing skills. This study also presents possibilities as to how the Japanese educational cultural method of teaching could be incorporated into the teaching of Japanese to non-Japanese speakers. In addition, this study indicates that language teachers facing a multicultural classroom might consider the international students’ educational cultural expectations and needs in learning. Those who develop the teaching curriculum are encouraged at a strategic level to examine other educational cultures and teaching practices from non-Anglophone countries and assess how they may be combined with CLT to reflect the new international characteristics of teaching and learning environments
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