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1 – 10 of 439Jiqing Chen, Shaorong Xie, Jun Luo and Hengyu Li
The purpose of this paper was to solve the shortage of carrying energy in probing robot and make full use of wind resources in the Antarctic expedition by designing a four-wheel…
Abstract
Purpose
The purpose of this paper was to solve the shortage of carrying energy in probing robot and make full use of wind resources in the Antarctic expedition by designing a four-wheel land-yacht. Land-yacht is a new kind of mobile robot powered by the wind using a sail. The mathematical model and trajectory of the land-yacht are presented in this paper.
Design/methodology/approach
The mechanism analysis method and experimental modeling method are used to establish a dual-input and dual-output mathematical model for the motion of land-yacht. First, the land-yacht’s model structure is obtained by using mechanism analysis. Then, the models of steering gear, servomotors and force of wing sail are analyzed and validated. Finally, the motion of land-yacht is simulated according to the mathematical model.
Findings
The mathematical model is used to analyze linear motion and steering motion. Compared with the simulation results and the actual experimental tests, the feasibility and reliability of the proposed land-yacht modeling are verified. It can travel according to the given signal.
Practical implications
This land-yacht can be used in the Antarctic, outer planet or for harsh environment exploration.
Originality/value
A land-yacht is designed, and the contribution of this research is the development of a mathematical model for land-yacht robot. It provides a theoretical basis for analysis of the land-yacht’s motion.
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In the First Russian Soaring Flight Competition at Feodosia (Crimea) in 1923, a very light “all‐wing” sailplane took part. The parabola plan shape of its wing, its small span and…
Abstract
In the First Russian Soaring Flight Competition at Feodosia (Crimea) in 1923, a very light “all‐wing” sailplane took part. The parabola plan shape of its wing, its small span and low aspect ratio raised general interest. The designer and pilot of this Flying Wing was the Russian student of aeronautical engineering, B. J. Tscheranowsky.
The Aslib Informatics Group and its predecessor the Co‐ordinate Indexing Group have made several attempts to understand the indexing process. This has been sought through seminars…
Abstract
The Aslib Informatics Group and its predecessor the Co‐ordinate Indexing Group have made several attempts to understand the indexing process. This has been sought through seminars and indexing projects. The seminars produced some data on an ad hoc basis and although most have been assembled they have not been reported previously. More recently a formal project, involving sixteen volunteer indexers, has been organized around five short New Scientist articles and the data from this exercise form the major component in the present study. An attempt has been made to correlate indexer performance with the original texts. There appears to be evidence to support the assertion that the selection of index entries is related to the structure of the original texts, especially the frequency of individual words.
Lourelay Moreira dos Santos, Guilherme Ferreira Gomes and Rogerio F. Coimbra
The purpose of this study is to investigate the aerodynamic characteristics of a low-to-moderate-aspect-ratio, tapered, untwisted, unswept wing, equipped of sheared wing tips.
Abstract
Purpose
The purpose of this study is to investigate the aerodynamic characteristics of a low-to-moderate-aspect-ratio, tapered, untwisted, unswept wing, equipped of sheared wing tips.
Design/methodology/approach
In this work, wind tunnel tests were made to study the influence in aerodynamic characteristics over a typical low-to-moderate-aspect-ratio wing of a general aviation aircraft, equipped with sheared – swept and tapered planar – wing tips. An experimental parametric study of different wing tips was tested. Variations in its leading and trailing edge sweep angle as well as variations in wing tip taper ratio were considered. Sheared wing tips modify the flow pattern in the outboard region of the wing producing a vortex flow at the wing tip leading edge, enhancing lift at high angles of attack.
Findings
The induced drag is responsible for nearly 50% of aircraft total drag and can be reduced through modifications to the wing tip. Some wing tip models present complex geometries and many of them present benefits in particular flight conditions. Results have demonstrated that sweeping the wing tip leading edge between 60 and 65 degrees offers an increment in wing aerodynamic efficiency, especially at high lift conditions. However, results have demonstrated that moderate wing tip taper ratio (0.50) has better aerodynamic benefits than highly tapered wing tips (from 0.25 to 0.15), even with little less wing tip leading edge sweep angle (from 57 to 62 degrees). The moderate wing tip taper ratio (0.50) offers more wing area and wing span than the wings with highly tapered wing tips, for the same aspect ratio wing.
Originality/value
Although many studies have been reported on the aerodynamics of wing tips, most of them presented complex non-planar geometries and were developed for cruise flight in high subsonic regime (low lift coefficient). In this work, an exploration and parametric study through wind tunnel tests were made, to evaluate the influence in aerodynamic characteristics of a low-to-moderate-aspect-ratio, tapered, untwisted, unswept wing, equipped of sheared wing tips (wing tips highly swept and tapered).
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THE Slingsby Sky is a British designed high‐performance sailplane and is intended for cross‐country and competition flying. The prototype Sky first flew in the summer of 1950 and…
Abstract
THE Slingsby Sky is a British designed high‐performance sailplane and is intended for cross‐country and competition flying. The prototype Sky first flew in the summer of 1950 and since that time the design has been put into limited production. The Sky has obtained several notable successes in competition flying, the most recent of which was the 1952 International Gliding Contests in Spain, where Sky's took the first, third and fourth places; the six machines which completed the contest all being placed in the first fourteen out of a total entry of forty.
BECAUSE soaring flight is a peacetime pursuit, sailplane development since 1939 has been negligible. Effort has necessarily been diverted into the design of large military gliders…
Abstract
BECAUSE soaring flight is a peacetime pursuit, sailplane development since 1939 has been negligible. Effort has necessarily been diverted into the design of large military gliders having no soaring ability. With so many out of touch for so long, it may be worth while to look back a little and examine the best of the immediate pre‐war period.
Hélène de Burgh‐Woodman and Jan Brace‐Govan
The purpose of the paper is to expand existing qualitative parameters in current marketing research discourse by integrating Barthesian theory into the study of subcultural…
Abstract
Purpose
The purpose of the paper is to expand existing qualitative parameters in current marketing research discourse by integrating Barthesian theory into the study of subcultural marketplaces.
Design/methodology/approach
While essentially conceptual in nature, this paper adopts a comprehensive intertextual, semiotic approach which argues for the substantive investigation of the marketing text as a foundation for understanding consumption in a subcultural context.
Findings
To date, the integration of Barthesian intertextual theory has proved to be an effective method of interrogating subculturally‐oriented materials.
Practical implications
Marketers, in commercial contexts, will access a greater depth of insight into the subcultural market by applying an intertextual, semiotic framework as demonstrated in this paper.
Originality/value
While marketing discourse has taken interest in semiotics, this has typically occurred via the work of US semiologists, rather than the French school in their organic form. This is one of the first papers to locate Barthes within the marketing paradigm as a potential analytical framework. The paper suggests ways in which his influential theories may be applied as a viable analytical tool in qualitative research.
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This I.A.T.A. Symposium held during the I.A.T.A. Technical Conferences at Puerto Rico in April 1953 had as its object the free exchange of views and experience primarily between…
Abstract
This I.A.T.A. Symposium held during the I.A.T.A. Technical Conferences at Puerto Rico in April 1953 had as its object the free exchange of views and experience primarily between helicopter manufacturers and civil aircraft operators. The helicopter has been in operation for about ten years. The types available have, however, been in the main small, single‐engined military aircraft, but technical developments now promise fairly large, multi‐engined helicopters suitable for public transport operation. At this juncture, therefore, a conference of this nature is particularly valuable. Of course, definitive conclusions could not be reached, but the results of such a gathering of the most knowledgeable people concerned with helicopter design and operation cannot fail to be of the greatest interest.
L.C. Ruspini, E. Dari, C. Padra, G.H. Paissan and N.N. Salva
The purpose of this paper is to present applications of the topological optimization method dealing with fluid dynamic problems in two- and three dimensions. The main goal is to…
Abstract
Purpose
The purpose of this paper is to present applications of the topological optimization method dealing with fluid dynamic problems in two- and three dimensions. The main goal is to develop a tool package able to optimize topology in realistic devices (e.g. inlet manifolds) considering the non-linear terms on Navier–Stokes equations.
Design/methodology/approach
Using an in-house Fortran code, a Galerkin stabilized finite element is implemented method to solve the three equation systems necessary for the topological optimization method: the direct problem, adjoint problem and topological derivative. The authors address the non-linearity in the equations using an iterative method. Different techniques to create holes into a two-dimensional discrete domain are analyzed.
Findings
One technique to create holes produces more accurate and robust results. The authors present several examples of applications in two- and three-dimensional components, which highlight the potential of this method in the optimization of fluid components.
Research limitations/implications
The authors contribute to the methodology and design in engineering.
Practical implications
Engineering fluid flow systems are used in many different industrial applications, e.g. oil flow in pipes; air flow around an airplane wing; sailing submarines; blood flow in synthetic arteries; and thermal and fissure spreading problems. The aim of this work is to create an effective design tool for obtaining efficient engineering structures and devices.
Originality/value
The authors contribute by creating an application of the method to design a tridimensional realistic device, which can be essayed experimentally. Particularly, the authors apply the design tool to an inlet manifold.
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