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THE serious nature of difficulties which might be encountered in tail spins, was brought forcibly to the attention of the Material Division of the U.S. Army Air Corps, in the Spring of 1926, when Lieutenant E. H. Barksdale lost his life in attempting to determine the cause of difficult recovery from spins in a military aeroplane being flight tested at Dayton, Ohio. Trouble in recovery from spins had been encountered in several instances in foreign countries, and one or two cases had occurred in the United States: however, the problem was not considered as one generally applicable to all aeroplanes, because, in most cases of previous trouble, the aeroplanes concerned possessed unusual design features which were thought to be mainly responsible for their abnormal behaviour. Prior to this time, general conjectures had been made, regarding probable reasons for difficult recovery from spins, but very little in the nature of systematic investigation had been attempted, consequently no generally applicable principles had been determined. Numerous studies had been made in wind tunnels, and it was recognised that the normal aerofoil would rotate automatically under certain conditions, but the magnitude of the forces involved, and therefore the ability of an aeroplane to recover a normal attitude by use of the controls, could not be readily determined by wind tunnel tests. A few flight tests had indicated that the centre of gravity location, with respect to the resultant air force vector on the lifting surfaces, influenced the type of spin and the case of return to a normal attitude.

Spinning slender bodies are affected by lateral Magnus forces and moments when exposed to cross-flow. The effects occurring for spinning bodies of revolution in combination with stabilising or control surfaces such as canards are not yet fully explained. Therefore the present work aims to investigate the phenomena arising from the interactions of a roll-decoupled guidance unit with a spinning rear body are investigated.

A generic tangential-ogive-cylinder projectile equipped with deflectable canards on a roll-decoupled nose is investigated by means of 3D Reynolds-averaged Navier–Stokes simulations at Mach number 2 for angles of attack up to 22 degrees. Different canard deflection angles up to 9 degrees are considered. Global aerodynamic coefficients as well as local flow fields are analysed to explain the interactions occurring between the roll-decoupled guidance unit and the spinning rear body.

The deflected canards lead to flow interactions resulting in lateral forces and moments even without a spinning motion of the rear part. Depending on the canard deflection angles, these forces act in or against the direction of the classical Magnus effect. For angles of attack smaller than 10 degrees it is possible for the current body geometry to directly superpose the lateral effects resulting from the fins for the non-spinning model with those occurring for the non-finned but spinning model to obtain the total forces and moments acting on a spinning model with canted canards. However, the lateral effects generated on the guidance unit itself are insignificant compared to the canard-induced effects on the rear body.

A detailed analysis of the interaction effects arising from a decoupled guidance unit containing canards with a non-spinning/spinning rear body is performed and the underlying phenomena are revealed.

As one natural fiber, spun silk is one of the top-grade textile materials and has attracted more and more attentions on textile processing. The purpose of this paper is to introduce one kind of pneumatic compact spinning, four-line compact spinning (FLCS), into the silk spinning, and study and comparatively analyze corresponding yarn and fabric qualities.

First, two kinds of spun silk and viscose blend yarns, 120 Nm (8.3 tex) and 205 Nm (4.9 tex), were spun on the common ring spinning frame FK501 and spinning frame modified by FLCS, respectively. Then, after the plying and singeing procedures, the ply yarns 120 and 205 Nm/2 were produced. The evenness, breaking strength, and hairiness of the spun bobbin yarns and ply yarns were tested and comparatively analyzed. Then, properties of corresponding woven fabric, including the weight, thickness, permeability, stiffness, softness, smoothness, draping, wrinkle recovery, hand-touching (RHV), were measured and comparatively analyzed.

For the spun yarns, it is shown that by using the compact spinning method, the comprehensive quality of spun-silk blend bobbin and ply yarns are improved. For the fabrics, it is shown that compared with the fabric made of ring yarn, the weight and thickness of fabric made of compact yarn decreased, and the air permeability of fabric increased, but the difference is tiny. Meanwhile, the stiffness, smoothness of fabric made of compact yarn increased slightly, but the softness decreased slightly, leading to a little worse fabric hand-touching.

In the paper, one kind of pneumatic compact spinning, FLCS, was introduced into the silk spinning, and corresponding yarn and fabric qualities were studied and comparatively analyzed.

Solospun technology is one of the most important new spinning methods, which is implemented by dividing Ring spinning triangle into several small primary triangles and one final triangle by a Solospun roller. That is, there are two parts of spinning triangle in the Solospun technology, including primary triangles part and final triangle part. In the general case, the primary triangles are much smaller than final triangle. Therefore, the purpose of this paper is to present theoretical study of Solospun yarn torqueby linking the fiber tension in the spinning triangle to yarn torque under the assumption that the primary triangles and the primary twist are ignored.

The theoretical model of the residual torque within Solospun yarn due to the fiber tension was given. Then, as an application of the proposed method, 14.6 tex cotton yarns were taken as an example for the numerical simulations. The fiber tension in the Solospun spinning triangles and corresponding yarn torque were simulated numerically by using Matlab software. The relationships between yarn torque and spinning triangle parameters are analyzed according to the simulation results. Furthermore, the properties of spun yarns produced by the Solospun and Ring spinning system are evaluated and analyzed by using the simulation results.

It is shown that comparing with the Ring spun yarn, Solospun yarn torque is a little larger. Meanwhile, with an increase of substrand number, the fluctuation of curve of average fiber tension in Solospun system is increased firstly, and then decreased, i.e. showing parabola shape, potentially leading to corresponding change of yarn torque.

In this paper, theoretical study of Solospun yarn torque is presented by linking the fiber tension in the spinning triangle to yarn torque under the assumption that the primary triangles and the primary twist are ignored. The theoretical model of the residual torque within Solospun yarn due to the fiber tension was given.

Presents the mechanical models of ring, rotor and air‐jet staple yarn formation. The analysis of formation peculiarities has enabled the establishment of differences among them in micro‐ and macrostructure as well as in their mechanical and physical properties. The comparison of yarn and fabric quality parameters will be very valuable for weavers, knitters, garment manufacturers, finishers and designers. Gives productivity, spinability and economic factors for ring spinning, OE‐rotor and air‐jet spinning processes.

THE phenomenon of spinning has apparently been known to some extent since the first days of flying, but for many years it was considered a dangerous evolution from which no one ever recovered. It was not generally known that recovery was possible until 1916, when a British pilot, Major F. W. Gooden, made a scries of experiments, in which he deliberately put his aeroplane into spins and brought it out by the use of the controls. After that the spin became an ordinary manoeuvre, into which any, except the largest aeroplanes, might be put. Since then, however, and particularly in recent years when aero‐planes have been put into longer spins, difficulty has sometimes been experienced in recovering. This has given rise to considerable research, starting about twelve years ago, but the problem is so complex that results which can be satisfactorily used in a general way are just starting to come in. In this paper I hope to cover briefly the present status of spinning research, and the main results which have been obtained to date. Only the steady spin and the recovery from it will be considered—not the problem of avoiding the spin entirely.

Several academic studies have examined the investment performance of initial public offerings (IPOs). Since the underwriters desire to have the offering sell out quickly, they have an incentive to underprice the securities offering. A number of studies have found that new equity issues are generally underpriced and produce positive abnormal short‐term returns. Like IPOs, spin‐offs are issues which are new to the public capital markets. However, unlike IPOs, spin‐offs do not involve an underwriter which determines the offering price of the security. Spin‐offs are also similar to corporate sell‐offs in that a parent company makes a decision to divest a division or subsidiary; however, in a spin‐off the business unit is not sold for cash or securities. Instead, spin‐offs occur when a parent corporation distributes its entire holdings of stock in a subsidiary on a pro‐rata basis to the parent's shareholders. These transactions have the effect of completing the separation of the assets and liabilities of the parent and the subsidiary. Thus, two separate public corporations with the same proportional equity holdings now exist whereas only one firm existed previously.

The aim of the paper is to present a theoretical approach and an empirical analysis of factors affecting the spin-off creation, as although research on spin-off has increasingly received attention in recent years, few studies have focused on the main factors of the spin-off creation.

Considering the exploratory nature of our research objectives, the Université Libre de Bruxelles cases were chosen to evidence macro-, meso- and microfactors that affect the university's ability to create a spin-off.

Many factors that affect the spin-off creation were evidenced.

A multilevel perspective for the spin-off analysis was offered.

Spinning triangle is a critical region in the spinning process of staple yarn, which geometry influences the distribution of fiber tension and determines the qualities of yarn directly. Therefore, the purpose of this paper is to investigate the fiber tension distribution at the twist point.

First, one theoretical model of fiber tension distributions at the twist point is given according to the motion law of fibers in the spinning triangle. Then, one calculation method of fiber tension at the twist point is given by two steps. First, the initial tension of each fiber at the front nip line caused by the yarn load should be calculated according to the models obtained based on the principle of minimum potential energy. Second, the fiber tensions at the twist point can be calculated using the obtained model in this paper. Finally, as an application of the proposed method, spinning triangles of a modified ring spinning system with a pair of offset device which can change the horizontal offset of the twist point to the symmetric axis of nip line of the spinning triangle continuously are studied. The fiber tension distributions are simulated numerically.

It is shown that the fiber tension distributions at the twist point can be determined by fiber feeding into and out the spinning triangle speed, the initial tension of each fiber at the front nip line, fiber tensile Young’s modulus and cross-sectional area, the number of fibers at spinning triangle and the individual fiber angle with the center fiber. The spinning experiment shows that taking appropriate right or left offset of the spinning triangle can help to improve the spun yarn qualities.

In this paper, the fiber tension distribution at the twist point is investigated. One theoretical model of fiber tension distributions at the twist point is given according to the motion law of fibers in the spinning triangle first. Then, one calculation method of fiber tension at the twist point has been given under the assumption that the initial tension of each fiber at the front nip line is caused by the yarn load.

Spun silk is one of the top grade textile materials, and its products have high added value and meet the needs of the market. However, the technology level and process design of silk spinning are still much lower than cotton spinning; especially singeing is applied on spun silk yarn, and generates waste materials. The purpose of this paper is to introduce a kind of pneumatic compact spinning, four-line compact spinning (FLCS), into silk spinning and study the corresponding spun yarn qualities.

First, taking the silk spinning frame FK501 as an example, the process of modification of FLCS is presented. Then, three kinds of spun silk yarns, 80 Nm (12.5tex), 100 Nm (10tex) and 120 Nm (8.3tex), are spun on the common silk spinning frame FK501 and the spinning frame modified with FLCS. The evenness, breaking strength and hairiness of spun yarns are tested and comparatively analyzed. After the ply yarn production, three singeing procedures should be applied on the ring ply yarns, while only two singeing procedures should be applied on the compact ply yarns, which is beneficial for material saving.

The results show that compared with ring spun silk yarns, the comprehensive quality of compact spun silk yarns is improved, especially the harmful long hairiness (=3 mm) of yarn. Compared with the single spun silk yarn, the comprehensive qualities of the ply yarn are improved; especially, the breaking strength of the ply yarns is two times larger than the single yarn. After singeing, the hairiness of the ply yarn is decreased greatly, and the evenness is also improved, while the strength is decreased. Compared with ring spun silk yarn, the singeing times of compact spun silk yarn can be decreased, and the gas consumption in each singeing is also decreased, which is beneficial for material saving.

In this paper, a kind of pneumatic compact spinning, FLCS, is introduced into the silk spinning. It is shown that compared with ring spun silk yarns, the comprehensive quality of compact spun silk yarns is improved, especially the harmful long hairiness (=3 mm) of yarn. After the ply yarn production, three singeing procedures should be applied on the ring ply yarns, while only two singeing procedures should be applied on the compact ply yarns, which is beneficial for material saving.