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Brown, Mark W. "Evaluation of the Impact of Timber Truck Configuration and Tare Weight on Payload Efficiency: An Australian Case Study". Forests 12, nr 7 (28.06.2021): 855. http://dx.doi.org/10.3390/f12070855.
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The forest industry tends to plan, and model transportation costs based on the potential payload benefits of increased legal gross vehicle weight (GVW) by deploying different configurations, while payload benefits of a configuration can be significantly influenced by the vehicle design tare weight. Through this research the relative benefit of increased legal GVW of different configurations is compared across Australia over a 13-year period from 2006 to 2019, by examining data collected post operation across multiple operations. This approach is intended to offer realistic insight to real operations not influenced by observation and thus reflect long-term operating behaviour. The inclusion of the three most common configuration classes in Australian forestry over a 13-year period has also allowed the exploration of load management between configurations and potential trends over time. When considering the legal GVW and the tare weight impacts across the fleets, the semi-trailer has an 8 t payload disadvantage compared to B-Doubles and 19.6 t disadvantage compared to road trains.
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Salmin, V. V., A. A. Kvetkin i A. S. Russkikh. "Choice of mission trajectory plans and conceptual design of electrical propulsion module for launching payloads into circumterrestrial orbits". VESTNIK of Samara University. Aerospace and Mechanical Engineering 19, nr 4 (31.12.2020): 58–69. http://dx.doi.org/10.18287/2541-7533-2020-19-4-58-69.
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The problem of increasing the efficiency of transport operations in space is currently coming to the fore. In the context of this problem, we investigated the possibility of developing a space transportation system including a chemical upper stage and an electric propulsion transport module capable of performing a specified range of space maneuvers. Electric propulsion module design was carried out for a given range of target orbits and payload mass with the provision of restrictions on the flight time. Calculation of the ballistic characteristics of the flight is performed and an optimal program of placing a low-thrust vehicle into orbit is defined. A procedure for defining the design parameters of a space transportation system and its conceptual design is proposed. The conceptual design of the space transportation system and the electric propulsion module were formed in the PTC Creo Parametric environment. On the basis of the results of the work, it can be concluded that it is possible to create a space transportation system with given parameters.
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Thamm, F. P., N. Brieger, K. P. Neitzke, M. Meyer, R. Jansen i M. Mönninghof. "SONGBIRD – AN INNOVATIVE UAS COMBINING THE ADVANTAGES OF FIXED WING AND MULTI ROTOR UAS". ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XL-1/W4 (27.08.2015): 345–49. http://dx.doi.org/10.5194/isprsarchives-xl-1-w4-345-2015.
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This paper describes a family of innovative fixed wing UAS with can vertical take off and land – the SONGBIRD family. With nominal payloads starting from 0.5 kg they can take off and land safely like a multi-rotor UAV, removing the need for an airstrip for the critical phases of operation. A specially designed flight controller allows stable flight at every point of the transition phase between VTOL and fixed wing mode. Because of this smooth process with a all time stable flight, very expensive payload like hyperspectral sensors or advanced optical cameras can be used. Due to their design all airplanes of the SONGBIRD family have excellent horizontal flight properties, a maximum speed of over 110 km/h, good gliding properties and long flight times of up to 1 h. Missions were flown in wind speeds up to 18 m/s. At every time of the flight it is possible to interrupt the mission and hover over a point of interest for detail investigations. The complete flight, including take-off and landing can be performed by autopilot. Designed for daily use in professional environments, SONGBIRDs are built out of glass-fibre and carbon composites for a long service life. For safe operations comprehensive security features are implemented, for example redundant flight controllers and sensors, advanced power management system and mature fail safe procedures. The aircraft can be dismantled into small parts for transportation. SONGBIRDS are available for different pay loads, from 500 g to 2 kg. The SONGBIRD family are interesting tools combining the advantages of multi-copter and fixed wing UAS.
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Mathanlal, Thasshwin, Anshuman Bhardwaj, Abhilash Vakkada Ramachandran, María-Paz Zorzano, Javier Martín-Torres, Charles S. Cockell, Sean Paling i Tom Edwards. "Subsurface robotic exploration for geomorphology, astrobiology and mining during MINAR6 campaign, Boulby Mine, UK: part I (Rover development)". International Journal of Astrobiology 19, nr 2 (3.10.2019): 110–25. http://dx.doi.org/10.1017/s147355041900020x.
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AbstractAutonomous exploration requires the use of movable platforms that carry a payload of instruments with a certain level of autonomy and communication with the operators. This is particularly challenging in subsurface environments, which may be more dangerous for human access and where communication with the surface is limited. Subsurface robotic exploration, which has been to date very limited, is interesting not only for science but also for cost-effective industrial exploitation of resources and safety assessments in mines. Furthermore, it has a direct application to exploration of extra-terrestrial subsurface environments of astrobiological and geological significance such as caves, lava tubes, impact or volcanic craters and subglacial conduits, for deriving in-situ mineralogical resources and establishing preliminary settlements. However, the technological solutions are generally tailor-made and are therefore considered as costly, fragile and environment-specific, further hindering their extensive and effective applications. To demonstrate the advantages of rover exploration for a broad-community, we have developed KORE (KOmpact Rover for Exploration); a low-cost, re-usable, rover multi-purpose platform. The rover platform has been developed as a technological demonstration for extra-terrestrial subsurface exploration and terrestrial mining operations pertaining to geomorphological mapping, environmental monitoring, gas leak detections and search and rescue operations in case of an accident. The present paper, the first part of a series of two, focuses on describing the development of a robust rover platform to perform dedicated geomorphological, astrobiological and mining tasks. KORE was further tested in the Mine Analogue Research 6 (MINAR6) campaign during September 2018 in the Boulby mine (UK), the second deepest potash mine in Europe at a subsurface depth of 1.1 km, the results of which will be presented in the second paper of this series. KORE is a large, semi-autonomous rover weighing 160 kg with L × W × H dimensions 1.2 m × 0.8 m × 1 m and a payload carrying capacity of 100 kg using 800 W traction power that can power to a maximum speed of 8.4 km h−1. The rover can be easily dismantled in three parts facilitating its transportation to any chosen site of exploration. Presently, the main scientific payloads on KORE are: (1) a three-dimensional mapping camera, (2) a methane detection system, (3) an environmental station capable of monitoring temperature, relative humidity, pressure and gases such as NO2, SO2, H2S, formaldehyde, CO, CO2, O3, O2, volatile organic compounds and particulates and (4) a robotic arm. Moreover, the design of the rover allows for integration of more sensors as per the scientific requirements in future expeditions. At the MINAR6 campaign, the technical readiness of KORE was demonstrated during 6 days of scientific research in the mine, with a total of 22 h of operation.
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Demircali, Anil, i Huseyin Uvet. "A STUDY OF UNMANNED GLIDER DESIGN, SIMULATION, AND MANUFACTURING". CBU International Conference Proceedings 5 (24.09.2017): 1064–70. http://dx.doi.org/10.12955/cbup.v5.1072.
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This paper describes a mini unmanned glider's design, simulation, and manufacturing with a wing-folding mechanism. The mini-glider is designed for the CANSAT 2016 competition, which has the theme of a Mars glider concept with atmosphere data acquisition. The aim is to facilitate transportation and to land it to the destination point. Having a light and compact design is important since it is a glider without an engine and it uses power only for the transmission of sensory data. The glider is produced with a wingspan which is 440 mm, and its longitudinal distance is 304 mm. The wings can be packaged in a fixed size container whose dimensions are 125 mm in diameter and 310 mm in height. The glider's weight is only 144 gr, and it can increase up to 500 gr with maximum with payload. The mechanism, which includes springs and neodymium magnets for wing-folding, is capable of being ready in 98 ms for gliding after separation from its container. The mini-glider is capable of telemetry, communications, and other sensory operations autonomously during flight.
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Demircali, Ali, i Huseyin Uvet. "Mini Glider Design and Implementation with Wing-Folding Mechanism". Applied Sciences 8, nr 9 (3.09.2018): 1541. http://dx.doi.org/10.3390/app8091541.
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This paper describes a mini unmanned glider’s design, simulation, and manufacturing with a novel wing-folding mechanism. The mini-glider is designed for CanSat competition, which has a theme of a Mars glider concept with atmosphere data acquisition. The aim is to facilitate the transportation of the glider and to land it on the destination point by following strict rules. Having a light and compact design is important since it uses power for the transmission of sensory data only. Dimensions of the glider is produced with a wingspan that is 440 mm and a length of 304 mm. The wings can be stowed in a fixed size container that has a diameter of 125 mm and a height of 310 mm. Its weight is only 144 g and it can increase up to 500 g maximum with a payload. The mechanism, which includes springs and neodymium N48 grade magnets for a wing-folding system, is capable of being ready in 98 ms for gliding after separating from its container. The mini-glider is capable of telemetering, communicating, and conducting other sensory operations autonomously during the flight.
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Borz, Stelian Alexandru, Marina Viorela Marcu i Maria Francesca Cataldo. "Evaluation of an HSM 208F 14tone HVT-R2 Forwarder Prototype under Conditions of Steep-Terrain Low-Access Forests". Croatian journal of forest engineering 42, nr 2 (14.01.2021): 185–200. http://dx.doi.org/10.5552/crojfe.2021.775.
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Forwarding technology is well established in use around the world but, at the same time, forwarders are expensive machines that require a good planning to ensure the sustainability of operations. In addition, forwarder market is characterized by a limited pool of customers, therefore innovation attempts may be limited compared to other product development industries. Since the steps towards a full automation of operations are still at their beginning, improvements of forwarder machines may rest in developing and integrating components that could contribute to an increased effectiveness. To respond to such challenges, the Forwarder2020 project developed innovative components that were integrated in a number of forwarder prototypes based on a market pull approach that resulted in a flexible adaptation to customer requirements and work environments. Since one of the typical work environments was that of low access forests, some components (i.e. suspended cabin and transmission system) were engineered to enable faster and safer operations and to economize fuel. As a common validation step is that of bringing field evidence on the performance improvement, this study evaluated the operational speed, productivity and fuel consumption of a forwarder prototype in conditions of a steep-terrain low-access forest. The main findings were very promising as the prototype was able to operate at significantly increased speeds and the fuel savings were evident. For an average forwarding distance of about 1.5 km, net productivity and efficiency rates were estimated at 14.4 m3/h and 0.07 h/m3, respectively. They were related to the availability of wood, and further improvement of such figures is possible by a better organization of tree felling and processing. Operational speed was affected by the condition of skid roads used for forwarding, which were harsh. During the transportation tasks developed on roads typical for forwarding, the machine was able to sustain average speeds estimated at 8 km/h. As a matter of fact, in such tasks, the dominant operational speed (almost in 100% of the cases) was higher than 5 km/h irrespective of the road condition. Hourly fuel consumption was estimated based on the time in which the engine was working and it amounted to 17.1 l/h. More importantly, by considering the forwarded payload in terms of volume and mass, the unit fuel consumption was estimated to be 1.25 l/m3 and 1.47 l/t, respectively. These results bring evidence on the performance improvement by modular innovation. In fact, such solutions could answer the challenges related to the sustainability of forest operations in low access forests.
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Garren, Austin M., M. Chad Bolding, W. Michael Aust, Angelo C. Moura i Scott M. Barrett. "Soil Disturbance Effects from Tethered Forwarding on Steep Slopes in Brazilian Eucalyptus Plantations". Forests 10, nr 9 (22.08.2019): 721. http://dx.doi.org/10.3390/f10090721.
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Traditional timber harvests on steep slopes have been conducted through labor-intensive and sometimes environmentally impactful methods, such as manual felling with chainsaws and extraction using bladed skid trails, winching, or cable yarding. Ground-based mechanized harvesting and primary transportation methods such as cut-to-length harvesters and forwarders have emerged in some parts of the world as low-impact, safe, and efficient alternatives to the aforementioned systems. However, when mechanized operations are used on steep terrain, problems such as poor stability, loss of traction, and increased soil disturbance can occur. Tethered or winch-assisted logging practices are being tested and applied in several countries to adapt to challenges associated with operating equipment on steep slopes while minimizing environmental impact. To better understand the feasibility of these systems, we conducted a designed experiment to quantify changes in soil properties and predicted erosion resulting from varying numbers of passes and payload levels by a forwarder operating on slopes ranging from 27 to 38 degrees. The machine was equipped with two different track configurations, tethered by either a machine-mounted or self-contained winch, in eucalyptus plantations in Brazil. On low slopes, bulk density significantly increased, but it did not increase on steeper slopes; this demonstrates traction winches’ effectiveness at reducing concentrated ground pressures. Rut depths were minimal and decreased with increasing slope classes due to reduced track slippage. Predicted erosion rates were high, primarily due to the extremely steep, long slopes and lack of adequate cover in some portions of the trail, illustrating the importance of proper erosion management practices on steep slopes.
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Franko, Josef, Shengzhi Du, Stephan Kallweit, Enno Duelberg i Heiko Engemann. "Design of a Multi-Robot System for Wind Turbine Maintenance". Energies 13, nr 10 (18.05.2020): 2552. http://dx.doi.org/10.3390/en13102552.
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The maintenance of wind turbines is of growing importance considering the transition to renewable energy. This paper presents a multi-robot-approach for automated wind turbine maintenance including a novel climbing robot. Currently, wind turbine maintenance remains a manual task, which is monotonous, dangerous, and also physically demanding due to the large scale of wind turbines. Technical climbers are required to work at significant heights, even in bad weather conditions. Furthermore, a skilled labor force with sufficient knowledge in repairing fiber composite material is rare. Autonomous mobile systems enable the digitization of the maintenance process. They can be designed for weather-independent operations. This work contributes to the development and experimental validation of a maintenance system consisting of multiple robotic platforms for a variety of tasks, such as wind turbine tower and rotor blade service. In this work, multicopters with vision and LiDAR sensors for global inspection are used to guide slower climbing robots. Light-weight magnetic climbers with surface contact were used to analyze structure parts with non-destructive inspection methods and to locally repair smaller defects. Localization was enabled by adapting odometry for conical-shaped surfaces considering additional navigation sensors. Magnets were suitable for steel towers to clamp onto the surface. A friction-based climbing ring robot (SMART— Scanning, Monitoring, Analyzing, Repair and Transportation) completed the set-up for higher payload. The maintenance period could be extended by using weather-proofed maintenance robots. The multi-robot-system was running the Robot Operating System (ROS). Additionally, first steps towards machine learning would enable maintenance staff to use pattern classification for fault diagnosis in order to operate safely from the ground in the future.
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Hyla, Paweł, Agnieszka Kosoń-Schab, Janusz Szpytko i Jarosław Smoczek. "Integrated Supervision for Supporting Control and Proactive Maintenance of Material Handling System". Journal of KONES 26, nr 1 (1.03.2019): 65–72. http://dx.doi.org/10.2478/kones-2019-0008.
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Abstract Material handling systems, as an important part of different type of manufacturing processes, face the same challenges as manufacturing industries pushed nowadays forward by innovative ideas and technologies to the next level loudly announced as industry 4.0. Development of the next generation of automated manufacturing systems involves advanced approaches to material handling systems design and their close integration with the higher levels of manufacturing and production control and management, e.g. manufacturing execution systems (MES), enterprise resource planning (ERP). In the presence of increasing demands for manufacturing process optimization, the role of supervisory level of material handling systems is much more advanced today, ensuring not only data acquisition, visualization, monitoring, supervisory control, as well as synchronization with the higher control levels (FEM, ERP), but also providing functionality for supporting maintenance and decision-making processes to reduce downtimes, operations and maintenance costs. The article deals with the integration of control and maintenance functions in the hierarchical control system of a crane. The supervisory system for supporting control and proactive maintenance is prototyped at the laboratory overhead travelling crane. The article presents the control-measurement equipment and intelligent software tools implemented in the supervisory control and data acquisition (SCADA) system to aid decision-making process in proactive maintenance. The overview of the main components of the supervisory control and proactive maintenance subsystems is provided, and their respective role in control, supervision, and proactive maintenance is explained. The crane’s supervisory control includes the stereovision-based subsystem applied to identify the crane’s transportation workspace, determine the safety and time-optimal point-to-point trajectory of a payload. The proactive maintenance module consists of the human machine interface (HMI) supporting decision-making process, intelligent tools for upcoming downtime/failure prediction, and the crane's girder inspection using the metal magnetic memory technique.
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Ledkova, T. A., i V. S. Aslanov. "Space Tethered System Control for Payload Delivery from a Circular Orbit". Mechanical Engineering and Computer Science, nr 11 (22.12.2017): 1–16. http://dx.doi.org/10.24108/1117.0001323.
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The article deals with the transportation operation of a payload delivery from a circular orbit using a space-tethered system. The use of the tether allows transferring the payload capsule to the reentry orbit without using the jet fuel. The whole transport operation can be divided into three stages: braking for the payload exit from the original orbit, flight along the elliptical orbit to the boundary of the atmosphere, and reentry. For braking at the first stage, an extended tether is used. Its length varies according to the swing principle. This principle allows us to swing the space tethered system and use the relative speed of the tether return swing to reduce the absolute payload rate at the tether end.The objective of this work is to develop a technique for selecting the parameters of the tether length control law and the moment of the payload separation from the tether, which provides the payload capsule landing taking into account the allowable thermal and dynamic loads at the atmospheric stage of its motion.The paper considers a planar motion of a mechanical system consisting of a satellite, a weightless tether and a payload. Presents equations describing the payload motion at the stages of joint motion, free orbital flight, and reentry. Proposes a technique for selecting the parameters of the tether length control law. As a criterion of efficiency, a functional has been used, which takes into account the dynamic and thermal loads at the atmospheric stage of the payload motion. This functional can be constructed numerically, as a result of a series of numerical calculations, for a system with given mass and geometric parameters. A comparison of the reentry payload using the well-known dynamic law of the tether control and the law based on the swing principle was carried out within the framework of research activities. It was shown that in the problem of the payload delivery from a circular orbit, the swing principle is more effective than dynamic deployment. The optimum value of the control law parameter is at the border concerning the tether deployment speed.The obtained results can be used at the design stage of space transportation systems containing extended tethers.
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da Cás, Pedro L. K., Carlos A. G. Veras, Olexiy Shynkarenko i Rodrigo Leonardi. "A Brazilian Space Launch System for the Small Satellite Market". Aerospace 6, nr 11 (12.11.2019): 123. http://dx.doi.org/10.3390/aerospace6110123.
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At present, most small satellites are delivered as hosted payloads on large launch vehicles. Considering the current technological development, constellations of small satellites can provide a broad range of services operating at designated orbits. To achieve that, small satellite customers are seeking cost-effective launch services for dedicated missions. This paper deals with performance and cost assessments of a set of launch vehicle concepts based on a solid propellant rocket engine (S-50) under development by the Institute of Aeronautics and Space (Brazil) with support from the Brazilian Space Agency. Cost estimation analysis, based on the TRANSCOST model, was carried out taking into account the costs of launch system development, vehicle fabrication, direct and indirect operation cost. A cost-competitive expendable launch system was identified by using three S-50 solid rocket motors for the first stage, one S-50 engine for the second stage and a flight-proven cluster of pressure-fed liquid engines for the third stage. This launch system, operating from the Alcantara Launch Center, located at 2 ∘ 20’ S, would deliver satellites from the 500 kg class in typical polar missions with a specific transportation cost of about US$39,000 per kilogram of payload at a rate of 12 launches per year, in dedicated missions. At a low inclined orbit, vehicle payload capacity increased, decreasing the specific transportation cost to about 32,000 US$/kg. Cost analysis also showed that vehicle development effort would claim 781 work year, or less than 80 million dollars. Vehicle fabrication accounted for 174 work year representing less than 23 million dollars per unit. The launch system based on the best concept would, therefore, deploy small satellite constellations in cost-effective dedicated launches, 224 work year per flight, from the Alcantara Launch Center in Brazil.
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Velychko, Lilia Olegovna, i Evgenia Alexandrovna Ermolenko. "YUZHNOYE`S POSITION IN WORLD PLANS FOR MOON EXPLORATION". Journal of Rocket-Space Technology 27, nr 4 (30.12.2019): 131–45. http://dx.doi.org/10.15421/451919.
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The article discusses the lunar programs of leading countries of the world: EU, India, People’s Republic of China, South Korea, Israel, Russian Federation, Japan, USA, as well as possible direction of cooperation between Ukrainian cooperation and mentioned countries. The US lunar program is the most attractive. NASA invites private companies which can become Yuzhnoye State Design Office partners. Perspective payload delivery means into lunar orbit are proposed: Space Launch System, Falcon Heavy, Straship. Marketing strategy was developed to achieve economic efficiency of the space launch system operation project, designed for payloads injection into the lunar orbit (with Mayak launch vehicle family, developed by Yuzhnoye State Design Office, as an example) due to covering all possible segments of commercial, as well as government launch market. At the same time, comparison of price and performance characteristics of space transportation services into low Earth orbit is shown as of 2019. The prospective demand for Mayak launch vehicle family within the framework of the US state program for the development of the Moon was determined. According to the results of the marketing research, it can be concluded that with the price of about 3 000 US dollars for launching 1 kg of payload into low Earth orbit (from 70 to 330 million US dollars for launch), Mayak launch vehicle family have the advantageous position on the launch market into low Earth orbit and lunar orbit in comparison with the competitive positions of other ILVs in this market segment.
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Goldin, Daniel S., Samuel L. Venneri i Ahmed K. Noor. "Fresh Air, Wide-Open Space". Mechanical Engineering 123, nr 11 (1.11.2001): 48–55. http://dx.doi.org/10.1115/1.2001-nov-1.
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This article focuses on space-based observations that are taking on unprecedented importance in national security strategy. The high cost of launching payloads to Earth orbit has impeded progress in the exploration of space, as well as in its commercial use and development. The application of biological concepts and principles to the development of technologies for engineering systems has led to the emergence of biomimetics, neuromimetics, and neuromorphic engineering. System integrity is absolutely essential to achieving this kind of far-reaching vision. The airspace system can be integrated with the other two sets of transportation services to form a comprehensive intermodal transportation system, functioning as one seamless whole, maximizing passengers’ and shippers’ options for convenience, efficiency, and reduced cost. A systems-engineering approach must be used to define requirements, reinvent processes, formulate operational concepts, evaluate them, and then launch goal-oriented technology activities to transform the concepts into realities.
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Kehayas, Nikolaos. "Earth-to-space and high-speed “air” transportation: an aerospaceplane design". Aircraft Engineering and Aerospace Technology 91, nr 2 (4.02.2019): 381–403. http://dx.doi.org/10.1108/aeat-08-2017-0196.
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Purpose The purpose of this paper is to attempt an aerospaceplane design with the objective of Low-Earth-Orbit-and-Return-to-Earth (LEOARTE) under the constraints of safety, low cost, reliability, low maintenance, aircraft-like operation and environmental compatibility. Along the same lines, a “sister” point-to-point flight on Earth Suborbital Aerospaceplane is proposed. Design/methodology/approach The LEOARTE aerospaceplane is based on a simple design, proven low risk technology, a small payload, an aerodynamic solution to re-entry heating, the high-speed phase of the outgoing flight taking place outside the atmosphere, a propulsion system comprising turbojet and rocket engines, an Air Collection and Enrichment System (ACES) and an appropriate mission profile. Findings It was found that a LEOARTE aerospaceplane design subject to the specified constraints with a cost as low as 950 United States Dollars (US$) per kilogram into Low Earth Orbit (LEO) might be feasible. As indicated by a case study, a LEOARTE aerospaceplane could lead, among other activities in space, to economically viable Space-Based Solar Power (SBSP). Its “sister” Suborbital aerospaceplane design could provide high-speed, point-to-point flights on the Earth. Practical implications The proposed LEOARTE aerospaceplane design renders space exploitation affordable and is much safer than ever before. Originality/value This paper provides an alternative approach to aerospaceplane design as a result of a new aerodynamically oriented Thermal Protection System (TPS) and a, perhaps, improved ACES. This approach might initiate widespread exploitation of space and offer a solution to the high-speed “air” transportation issue.
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Yoshida i Takata. "Uncertainty Simulation of Wood Chipping Operation for Bioenergy Based on Queuing Theory". Forests 10, nr 9 (19.09.2019): 822. http://dx.doi.org/10.3390/f10090822.
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Managing uncertainty is the way to secure stability of the supply chain. Uncertainty within chipping operation and chip transportation causes production loss. In the wood chip supply chain for bioenergy, operational uncertainty mainly appears in the moisture content of the material, chipping productivity, and the interval of truck arrival. This study theoretically quantified the loss in wood chip production by applying queuing theory and stochastic modelling. As well as the loss in production, the inefficiency was identified as the idling time of chipper and the queuing time of trucks. The aim of this study is to quantify the influence of three uncertainties on wood chip production. This study simulated the daily chip production using a mobile chipper by applying queuing theory and stochastic modelling of three uncertainties. The result was compared with the result of deterministic simulation which did not consider uncertainty. Uncertainty reduced the production by 14% to 27% compared to the production of deterministic simulation. There were trucks scheduled but not used. The cases using small trucks show the largest daily production amount, but their lead time was the longest. The large truck was sensitive to the moisture content of material because of the balance between payload and volumetric capacity. This simulation method can present a possible loss in production amount and enables to evaluate some ways for the loss compensation quantitatively such as outsourcing or storing buffer. For further development, the data about the interval of truck arrival should be collected from fields and analyzed. We must include the other uncertainties causing technical and operator delays.
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Jia, Haiying, Vishnu Prakash i Tristan Smith. "Estimating vessel payloads in bulk shipping using AIS data". International Journal of Shipping and Transport Logistics 11, nr 1 (2019): 25. http://dx.doi.org/10.1504/ijstl.2019.096864.
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Jia, Haiying, Tristan Smith i Vishnu Prakash. "Estimating vessel payloads in bulk shipping using AIS data". International Journal of Shipping and Transport Logistics 11, nr 1 (2019): 25. http://dx.doi.org/10.1504/ijstl.2019.10017649.
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Bernard, M., K. Kondak i G. Hommel. "Load transportation system based on autonomous small size helicopters". Aeronautical Journal 114, nr 1153 (marzec 2010): 191–98. http://dx.doi.org/10.1017/s0001924000003638.
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Abstract This paper is devoted to modelling and control algorithms for a slung load transportation system composed of one or multiple helicopters, where the load is coupled by the means of flexible ropes (see Fig. 1). The coupled helicopter system overcomes the payload limitation of a single small size helicopter, while keeping most of its advantages: small costs of operation, low maintenance costs and increased safeness. Therefore, the system can be utilised whenever the use of full size helicopters is impossible, too expensive or prohibited by law. We focus on the deployment and repairing of distributed sensor networks, using a transportation system based on multiple small size helicopters. A possible real world application is the deployment of fire fighting equipment, where space limitation of the fire trucks prohibits the application of bigger UAVs and using full size helicopters is too dangerous. The problem of load transportation using one or two full size helicopters (twin lift helicopter system), connected to the load by means of flexible ropes, has been discussed in the aerospace research community at least since 1960. We have shown in our previous work that there is a fundamental difference in the mathematical description between small and full size helicopters. Therefore, also the control design for the case of small size helicopters needs to be different. To our knowledge, the control of a slung load transportation system composed of multiple small size helicopters has not been studied until now. In this paper, the complete mechanical setup of the slung load transportation system based on one or more small size helicopters is presented. This includes a short description of the used UAVs, the additionally required sensors, and how the load is mounted. A model of one/multiple helicopters transporting a load is introduced. This model is used in a simplified form for the controller design and in full form for simulation. The controller for one and two helicopters, which is based on a state feedback controller, as well as the controller for three and more helicopters, which is based on a non linear controller, are explained in detail. Both controllers utilise an underlying non-linear orientation controller. We propose a feedback loop, based on forces measured in the ropes, to compensate for the influence of the rope. The controllers were tested in simulation and in real flight experiments. The world wide first flight experiment with three coupled helicopters was successfully conducted at the end of 2007.
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Clayton, A., i M. Lai. "Characteristics of large truck–trailer combinations operating on Manitoba's primary highways: 1974–1984". Canadian Journal of Civil Engineering 13, nr 6 (1.12.1986): 752–60. http://dx.doi.org/10.1139/l86-110.
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Weight and dimension regulations governing large truck operations in Manitoba and western Canada generally have been substantially relaxed since 1974. These changes have facilitated the use of larger and heavier truck–trailer combinations on highways throughout Manitoba and on interconnecting highways in adjacent jurisdictions. Effective engineering of these highways and their bridges requires a solid understanding of the physical and use characteristics of the truck–trailer combinations that have been, and are being, adopted by the trucking industry in response to the relaxed regulatory environment.This paper examines certain of these characteristics based on an analysis of hitherto unpublished on-road truck surveys conducted over the years by the Manitoba Department of Highways and Transportation. The following characteristics are examined: (i) changes in the truck fleet mix, (ii) changes in the tare weights of large vehicle combinations, (iii) distributions of gross vehicle weights for particular vehicle combinations, (iv) distributions of weight payloads handled by particular vehicle combinations, and (v) certain dimensional characteristics of import to understanding vehicle loads on highways and bridges. As possible, these characteristics (and changes in them) are related to prevailing weight and dimension regulations (and changes in them). Key words: weight and dimension regulations, truck–trailer combinations, truck weights, axle spacings, on-road truck surveys.
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Kim, Cheol, Sun Goo Kim i Yong Yun Kim. "Development of Composite Optical Bench Structures on a Satellite Considering Launch and Space Environments". Key Engineering Materials 334-335 (marzec 2007): 457–60. http://dx.doi.org/10.4028/www.scientific.net/kem.334-335.457.
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Satellite structural components must be able to withstand various loading and environments that will experience during integration, tests, transportation, launch, and on-orbit operation. A polymeric composite optical bench that fixes delicate optical payloads such as a camera or a telescope was developed based on static strength, thermal deformation, and vibration. The optical bench consists of composite sandwich panels with and without a hole and composite struts with end fittings. In this paper, the optimum stacking sequence of the composite optical bench was calculated to minimize severe thermal deformations during orbital operation using a genetic algorithm and the finite element analysis. Then, the optimum design is evaluated whether it withstands launch loads (high inertia, vibration, etc.), that are not usually significant compared to orbital thermal loadings, or not. The thermal deformation of sandwich panels was minimized at the stacking sequence of [0/±45]s and that of composite struts was lowest at the angle of [02/90]s. There was no buckling in the compressive loading. By vibration analysis, the natural frequencies of the composite components were much higher than aluminum structures (i.e., sandwich panel: 10.7%; strut: 27.79%) and the stiffness condition expected was satisfied. Then, a composite optical bench was fabricated for tests and all analyses results were verified by structural testing. There were good correlations between two results. To increase the structural stiffness, several Nitinol shape memory alloy wires installed on it and the natural frequencies were measured.
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Yang, Xiufeng, Longlong Chang i Néstor O. Pérez-Arancibia. "An 88-milligram insect-scale autonomous crawling robot driven by a catalytic artificial muscle". Science Robotics 5, nr 45 (19.08.2020): eaba0015. http://dx.doi.org/10.1126/scirobotics.aba0015.
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The creation of autonomous subgram microrobots capable of complex behaviors remains a grand challenge in robotics largely due to the lack of microactuators with high work densities and capable of using power sources with specific energies comparable to that of animal fat (38 megajoules per kilogram). Presently, the vast majority of microrobots are driven by electrically powered actuators; consequently, because of the low specific energies of batteries at small scales (below 1.8 megajoules per kilogram), almost all the subgram mobile robots capable of sustained operation remain tethered to external power sources through cables or electromagnetic fields. Here, we present RoBeetle, an 88-milligram insect-sized autonomous crawling robot powered by the catalytic combustion of methanol, a fuel with high specific energy (20 megajoules per kilogram). The design and physical realization of RoBeetle is the result of combining the notion of controllable NiTi-Pt–based catalytic artificial micromuscle with that of integrated millimeter-scale mechanical control mechanism (MCM). Through tethered experiments on several robotic prototypes and system characterization of the thermomechanical properties of their driving artificial muscles, we obtained the design parameters for the MCM that enabled RoBeetle to achieve autonomous crawling. To evaluate the functionality and performance of the robot, we conducted a series of locomotion tests: crawling under two different atmospheric conditions and on surfaces with different levels of roughness, climbing of inclines with different slopes, transportation of payloads, and outdoor locomotion.
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Altuğ, Erdinç, i Abdullah Türkmen. "A Novel Mini Jet Engine Powered Unmanned Aerial Vehicle: Modeling and Control". Unmanned Systems, 14.05.2021, 1–13. http://dx.doi.org/10.1142/s2301385022500017.
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Significant progress has been made in recent years on personal air vehicles (PAVs), which offer independent and autonomous urban transportation. On-demand parcel delivery drones and heavy-lift drones are gaining serious attention. Although various designs for these systems have been put forward, they still have not reached sufficient maturity. The current systems provide somehow satisfactory operation, but many of these systems are limited in payload capacity and flight duration, and not suitable for future operations. In this paper, we propose a novel thrust system that uses multiple mini jet engines. Unlike electric motors, the jet engine thrust cannot vary rapidly. This led us to design and develop a thrust vectoring system for each jet engine. This proposed system has the potential to enable drones to carry more payload and achieve longer flight times. This paper discusses the design and modeling of the system as well as the stabilization algorithms that satisfactorily stabilize the proposed system. We presented that due to motor lag, thrust variations cannot stabilize the vehicle. We showed that the use of a thrust vectoring mechanism with LQR-based controller can overcome the effects of motor lag and stabilize the vehicle, successfully.
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Yeow, Lih Wei, i Lynette Cheah. "Comparing Commercial Vehicle Fuel Consumption Models using Real-World Data under Calibration Constraints". Transportation Research Record: Journal of the Transportation Research Board, 26.04.2021, 036119812110074. http://dx.doi.org/10.1177/03611981211007478.
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Assessing commercial road vehicle fuel use at a high spatiotemporal resolution helps in understanding underlying usage patterns and informs future interventions toward fuel-efficient freight planning and operations. With the use of global navigation satellite systems in fleet tracking and advancements in driver activity surveys, instantaneous fuel consumption models can calculate fuel use in high resolution using inputs like speed and acceleration derived from GPS data. Given that several models exist, there is a need to compare fuel use estimates from different models, especially under the constraint of limited data for calibration. This study evaluates the accuracy of fuel use estimates from three fuel consumption models (COPERT 4, SIDRA TRIP, and MOVES) applied to 10 diesel commercial road vehicles in Singapore over a standardized drive cycle (NEDC) and real-world activity data derived from GPS traces using the method of space-time path segments and road grade obtained from a digital elevation model. Changes in model performance are examined when supplementary on-board diagnostics (OBD) data and payload information are used. The models gave varying fuel use estimates over the NEDC, especially for heavier vehicles in the sample. When applied to real-world data, SIDRA TRIP was found to be the most accurate for the context studied. SIDRA TRIP’s performance improved consistently when supplemented with OBD and payload information. This comparison approach allows analysts to select the most suitable model for a given context, and take steps toward more sustainable freight transportation.
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Ismail, Abdi, Achmad Zubaydi, Bambang Piscesa, Tuswan Tuswan i Rizky Chandra Ariesta. "STUDY OF SANDWICH PANEL APPLICATION ON SIDE HULL OF CRUDE OIL TANKER". Journal of Applied Engineering Science, 19.04.2021, 1–9. http://dx.doi.org/10.5937/jaes0-30373.
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A lightweight sandwich plate system (SPS) consisted of steel faceplate and polyurethane elastomer composite cores have excellent potential to be applied on the ship structure. Steel faceplate and polyurethane elastomer (PU) cores are frequently applied, but PU has a relatively high material cost. More economical material can be achieved by combining PU with fiberglass as a fiberglass reinforced polyurethane elastomer (FRPU) composite. In this study, the sandwich consisting of steel faceplate and FRPU composite core material is applied in the tanker side hull by investigating the structural performance and weight saving analysis using finite element analysis (FEA). Four sandwich side hull models using different stiffener configurations are compared with the conventional stiffened plate model. The result shows the promising SPS application in terms of structural strength and weight savings. The remarkable stress reduction, deformation, and structural weight reduction due to SPS application are discussed. Therefore, its weight reduction can increase the ship payload so that ship operations will be cost-effective.
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Rotty, Fernando Fransiskus, Freddy Franciscus i Ericko Chandra. "Analisis Penentuan Komposisi Optimum Kargo Dan Pax Pesawat Boeing 787 - 8 Dan Airbus 330 – 900 Pada Rute Jakarta – Dubai Menggunakan Optimasi Linear Programming". Jurnal Teknologi Kedirgantaraan 6, nr 2 (28.08.2021). http://dx.doi.org/10.35894/jtk.v6i2.37.
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Abstract - The need for airplanes is increasing every day, this is due to the increasing number of passengers and cargo shipments from one area to another. Therefore, airlines need to provide optimal, safe, and efficient cargo and passenger transportation services so that the delivery of goods and passengers can run according to correct procedures. Opportunities in the business of transporting passengers and shipping cargo must be utilized properly by each airline by purchasing planes so that the shipping process from one area to another can quickly arrive at its destination. The purpose of this paper is to find the optimum value of the two aircraft between the Boeing 787-8 and the Airbus 330-900 in terms of the effect on the range, operational costs and to find out which aircraft is more profitable for operating costs on the Jakarta - Dubai route, using linear optimization. programming. Based on the results of the analysis that the optimum point for the calculation of linear programming optimization, the Boeing 787-8 aircraft obtained results (Max payload 41,075 kg, Fuel 6,657 kg, Max Fuel 101,323 kg) where these three results become a limitation for airlines to know the maximum usage of payload and fuel compared Airbus 330-900 aircraft obtained results at the point (Max payload 45,000 kg, Fuel 4,728 kg, Max Fuel 111,272 kg) so that the optimization results are obtained, for Boeing 787-8 aircraft with a max payload of 41,075 kg, max pax 359, max cargo 15,945 kg , compared to Airbus 330-900 with a max payload of 45,000 kg, max pax 460, max cargo 12,800 kg, so it can be concluded that the results of linear programming optimization and the calculation of the operational costs of the Boeing 787-8 aircraft are more optimal with a figure of Rp. 1,541,334,803.96 but in terms of revenue the Airbus 330-900 is bigger than the Boeing 787-8.