Space Aircraft Research Articles

Estimation of fracture conditions of ceramics by thermal shock with laser beams using the maximum compressive stress criterion.

Structural ceramics are attracting attention in the development of space ships, aircraft and nuclear fusion reactors because they have excellent wear-resistant and heat-resistant characteristics. However, in some applications it is anticipated that they will be exposed to very high temperatures of the order of thousands of degrees. Therefore, it is very important to investigate their thermal shock characteristics. In this report, the distributions of temperatures and thermal stresses of cylindrically shaped ceramics under laser beams are discussed using the finite element computer code (MARC) with arbitrary quadrilateral axisymmetric ring elements. The relationships between spot diameters of laser beams and maximum values of compressive thermal stresses are derived for various power densities. From these relationships, a critial fracture curve is obtained, and it is compared with the experimental result.

Unsteady flow of blood through arteries in vibration environments

The paper concerns the development of a mathematical model for the study of the influence of whole-body accelerations (vibrations) on the flow of blood in single arteries. Human and subhuman prinates are often exposed to vibration environments in various ways. When a subject is placed on a vibration table, whole-body vibration is instantaneously induced in the body. In addition, while riding in vehicles or while flying in aircraft or spacecraft, man is often subjected to unintentional body accelerations. Vibration physiology is thus of great concern in the field of space and military aircraft. In order to study the fully developed flow-field in a specimen of artery, a suitable mathematical model is developed here by employing the momentum integral method. The effect of microrotation of the blood cells on the flow-field has been duly accounted for. The validity of the analysis is illustrated through the presentation of computational results for the mass flow magnitude when a specific arterial segment is exposed to a sinusoidal pressure gradient and wall vibration acting in phase/opposition. For mass flow stoppage, critical values of the phase angle by which the sinusoidal wall vibration leads the sinusoidal pressure pulse, in the case when the angular frequency of the wall vibration is equal to that of the pressure pulse, and a nondimensional parameter representing the ratio of the peak wall velocity to the Poiseuille centreline relative velocity for the peak pressure gradient, are also investigated.

Reinforced Substrates: Aerospace Technology Introduces a New Concept for Industrial Fabrics

The purpose of this research and development project was to determine if an engineered system of reinforcing substrates as developed by aerospace technology is adaptable to industrial fabrics. The creation of an entirely new breed of industrial fabrics, however, also requires solid, demonstrative proof that such fabrics will satisfy an existing need better than existing materials and practices or introduce fabricators and manufacturers to an entirely new market. Very thin films used in commercial and space aircraft for insulation covering require effective reinforcement both for fabrication and strength purposes. To keep weight at a minimum, a reinforcing system of bonded, oriented, and continuous strand yarns was developed. In this system the fill yarns are coated with an adhesive, passed over the warp, and bonded to a substrate in a continuous procedure. Fill yarn spacing is variable at will. Virtually any size, type, and combination of yarns can be used. Adhesives are selected to match the end use of the reinforced product. As a part of the project, this reinforcing system was applied to many types of plastic films and to both woven and non-woven substrates. Laboratory and field work on this project began in August 1976. Over 400 different types of fabrics were constructed and evaluated for possible use in approximately 60 industrial applications.

Functional Polymers and its Perspective

Functional Polymers include polymers of both high performance and high functionality. They had attracted special attention and had been widely studied since 1968, when the first petroleum crisis had occured.In order to develop functionality, the polymers have to be processed by special method, and to be applied in a suitable system. Functional polymers will be useful for the development of high technology in future.In this paper, space technology, aircraft and car technology, new field of chemical engineering, communication and information technology, technology of energy and med-ical engineering are taken up as the important high technology area, and contribution of functional polymers to the development of these new fields are described. As the examples of functional polymers which contribute to the development of space technol-ogy and aircraft and car technology, new development of carbon fiber and three new polymer processing methods are shown.In the field of new chemical engineering, there are two important chemical proc-esses, i. e, highly efficient reaction process and separation and purification process for hard separable materials. In this paper, carbon sieve and polymers which memorize the molecular structure and catch these materials are shown.Functional polymers which contribute to the development of communication and information technology, are seen especially in the field of optoelectronic technology. Among them, organic optical fiber and registration material of optoelectric informa-tion is shown.In the field of energy, renewable energy is considered important replacing fossil fuel such as coal and petroleum. The most important technology for renewable energy is how to get energetic material such as ethanol at low cost, In this paper, develop-ment of fermentation process and separation process of ethanol from water by using membrane is shown.Development of medical engineering is much affected by functional polymers. As the examples, artificial kidney, artificial liver, artificial heart, diagnosis by bio-sensor, bio-separator and affinity therapy are described.

Pursuit-Evasion of Two Aircraft in a Horizontal Plane

Pursuit-evasion between two aircraft in a horizontal plane is analyzed as a differential game using point-mass aircraft models. A suitable choice of real-space coordinates confers open-loop optimality on the game. The solution in the small is described in terms of the individual aircraft's extremal trajectory maps (ETM). Each is independent of role, adversary, and capture radius. An ETM depicts the actual trajectories flown by the aircraft in real space. A template method of generating constant control arcs is described. This is used to investigate bank saturation and throttle switching behavior exhaustively. Sections of the barrier are obtained by iteratively choosing pairs of extremals from the two ETM's. NALYTICAL studies of aircraft pursuit-evasion techniques seek to determine the influence of aircraft and weapon system performance upon combat outcome and to derive idealized tactics. Aircraft pursuit-evasion is considerably more difficult to analyze than optimal maneuvers because a closed-loop solution is a must in a differential game situation and exceptional and discontinuous surfaces are the rule rather than an exception. Analyses of aircraft pursuit-evasion have simplified the situation along three lines. First, pursuit-evasion has been studied as variants of the Game of Two Cars. 1~7 In these, the aircraft are assumed to fly at constant altitude and speeds; their optimal paths are composed of circular arcs and straight line segments. Second, in the energy approach,8'11 the aircraft are modeled realistically in terms of their energies and relative heading. However, the relative positions of the aircraft are ignored. The differential game studied is again trimensional. Third, in the dynamic modeling12 and numerical approaches, 13'16 combat is formulated as a game of prescribed duration thus avoiding discontinuous and exceptional surfaces. Even then, near-optimal closed-loop solutions have only been obtained for simple examples.16 Thus an analysis of constant-altitude pursuit-evasio n with varying aircraft speeds portrays the situation realistically. It also takes on, for the first time, a free-time combat game with five state variables. The game is formulated in a real space whose origin and axes change from party to party. The equations decompose into two sets, one for each aircraft. These are coupled in terms of the terminal quantities alone. This simplifies the solution in the small and effects significant computational economy. Moreover, each aircraft's optimal motion in real space can be described in terms of an extremal trajectory map (ETM) which is independent of the adversary and of role. The ETM thus serves as a measure of an individual aircraft's combat performance.

炭素繊維強化樹脂(CFRP)使用のカセッテシステムについて

The front plate material of cassette always have been used Bakelite cassette and Aluminum cassette. Bakeltie cassette has low X-ray absorption but poor screen-film contact and heavy. Aluminum cassette provides good screen-film contact but higher X-ray absorption. Bakelite cassette and aluminum cassette was reported by S, Sasaki. M, Nakamura and Y, Yamamoto etc. They are emphasized, front plate material have direct effects upon image quality and patient dose. Recentry, Carbon fibre has developed and applications in space craft and aircraft-, rotating parts, pressure vessels, sporting equipments. I am introduced this Carbon fiber reiforced plastic for X-ray cassette system. Results, X-ray absorption is 20 percent low compare Carbon fiber reinforced plastics cassette (CFRP) with aluminum cassette, therfore enhanced image quality and reduced patient dose. Specially, Carbon fiber reinforced plastic cassette is light weight, tough, elastic and durability (heat, chemicals, pressure etc.). In this study, Carbon fiber reinforced plastic used "TORAYCA" made by Toraya company.

Utility of landsat coverage in small scale geomorphological mapping-some examples from India

With the launching of LANDSAT—1 in 1972 followed by LAND-SAT-2 and 3 in 1975 and 1978 respectively, a new tool is now available to earth scientists for a synoptic overview of the earth forms. Existing small scale geological maps, soil maps and forest resource maps are constantly being updated with the help of LANDSAT imagery. The paper highlights the utility of LANDSAT imagery in preparing small scale geomorphological maps by citing examples from such diversified terrains as the Himalaya and rain forest area in the north and NE India and part of east coast. The advantage of conjunctive use of space craft, aircraft and ground data in enhancing the detail and quality of the map is discussed. Further the direct relationship between landform and landuse is brought out in the map.

Designing an Adaptive System to Improve Piloting Characteristics of Transport Space-craft

Summary The necessity of creating an adaptive system for the improvement of piloting characteristics of a transport space aircraft is substantiated. On the base of stability condition, a specific synthesis of laws for correcting coefficients in damping, stability and controllability circuits is carried out. The laws derived assume different versions of practical realization. The technique of choosing the preferable variant, according to the criteria combination, taking into account, parallel with dynamic indices, weight, realiability and so on is discussed.

Arms Limiting and Force Adjusting Arrangements in the Northern Gap Area

The author starts out by delineating the existing system of unilateral arms control measures which is observed by Norway. He distinguishes between unilateral formal measures on the one hand and semi-formal measures on the other. To the former belong the policy on foreign bases and nuclear weapons while the latter include the restrictions applying to allied military exercises and the presence of allied aircraft in Norwegian air space and naval vessels in Norwegian territorial waters. The present era of political reconstruction in Europe may generate force reduction and force adjustment regulations as part of the security infrastructure of the post-cold war Europe. Thus the Norwegian constraints would have to be viewed in a novel context and their possible multilateralization considered. Against the background of a delineation of the relationship of forces in the Northern Cap area the author suggests various activity regulation measures aimed at depoliticizing military force in the area (restrictions on manoeuvres, new stationing of forces, notification of manoeuvres). The naval situation in the Norwegian Sea illustrates the interrelationship between the regional security situation and the superpower balance. The outcome of SALT will affect the situation, but the author also suggests various arrangements involving ceilings on naval activity in the Norwegian Sea.

Arms Limiting and Force Adjusting Arrangements in the Northern Cap Area

The author starts out by delineating the existing system of unilateral arms control measures which is observed by Norway. He distinguishes between unilateral formal measures on the one hand and semi-formal measures on the other. To the former belong the policy on foreign bases and nuclear weapons while the latter include the restrictions applying to allied military exercises and the presence of allied aircraft in Norwegian air space and naval vessels in Norwegian territorial waters. The present era of political reconstruction in Europe may generate force reduction and force ad justment regulations as part of the security infrastructure of the post-cold war Europe. Thus the Norwegian constraints would have to be viewed in a novel context and their possible multilateralization considered. Against the background of a delineation of the relationship of forces in the Northern Cap area the author suggests various activity regulation measures aimed at depoliticizing military force in the area (restric tions on manoeuvres, new stationing of forces, notification of manoeuvres). The naval situation in the Norwegian Sea illustrates the interrelationship between the regional security situation and the superpower balance. The outcome of SALT will affect the situation, but the author also suggests various arrangements involving ceilings on naval activity in the Norwegian Sea.

A Method of Calculating Space Free Resonance Modes of an Aircraft

The problem of deducing resonance modes of vibration of an aircraft in free space is a concomitant of flutter calculations if the number of degrees of freedom used is to be small. When the structure is complex in that it involves wings, fuselage and tailplane, each of which possesses infinitely many normal modes, it becomes apparent that the number of point masses which must be considered, in constructing a dynamical equivalent to give a sufficient coverage of the frequency range in which flutter is likely, is very large. For example, it may be necessary to use four rods per wing and per tailplane and four point masses on the fuselage. This would involve 8 + 8 + 4 degrees of freedom, and if the usual technique of characteristic roots is used it would be necessary to consider a characteristic root matrix of order 20 × 20.