Plane Collision Research Articles

Calibration of Collision Recovery Coefficient of Corn Seeds Based on High-Speed Photography and Sound Waveform Analysis

Compared with the movement of corn seeds in the sowing machine, the movement in the threshing machine is more intense. The collision between corn seeds and threshing parts and other corn seeds will not only change the movement path of corn seeds in the threshing clearance but also cause damage to corn seeds. Therefore, when using discrete element simulation technology to optimize the critical components of corn threshing machinery, it is necessary to measure corn seeds’ accurate collision recovery coefficient. However, when measuring the collision recovery coefficient between corn seeds, there will be multi-point collisions between corn seeds, affecting the measurement results’ accuracy. In order to solve this problem, this study combined high-speed photography and the sound waveform of corn seed collision to eliminate the interference of the multi-point collision phenomenon and improve the accuracy of measurement results. According to the above test method, the contact parameters of corn seeds were measured. Finally, the corn–corn rolling friction coefficient and corn–PMMA rolling friction coefficient were 0.0784 and 0.0934, respectively. The corn–corn static friction coefficient was 0.32, and the corn–PMMA static friction coefficient was 0.445. The corn–corn collision recovery and corn–PMMA collision recovery coefficients were 0.28 and 0.62, respectively. After that, the method’s reliability and the measurement results’ accuracy were verified by the plane collision test and repose angle test.

Theoretical Model of the Axial Residual Velocity of PELE Projectiles Penetrating Thin Metal Targets

With the increase of battlefield target diversity and protection mobility, the disadvantages of traditional armor piercing warheads have gradually become prominent. The conception of the PELE (penetration with enhanced lateral efficiency) projectile was thus proposed. The axial residual velocity of the projectile is a very important indicator of a PELE projectile, which mainly reflects the penetration ability of the PELE projectile. The PELE projectile is a symmetrical structure, so the collision problem can be simplified to plane collision. Furthermore, the two-dimensional plane is axisymmetric, and so it can be further simplified to one-dimensional collision. Based on simplification and assumptions, the mechanism of a PELE projectile penetrating a thin metal target plate was studied using the shock wave theory, and a theoretical model of axial residual velocity has been established in this article. The energy loss during the penetration process was divided into the following parts: the kinetic energy increment of the target plug in the impact region, the internal energy increment of the outer casing and inner core, and the shear energy dissipation of the projectile against the target plate. In addition, the specific methods of determining the energy loss of each part are given in detail. According to the conservation of energy, the approximate calculation formulae of the axial residual velocity of a PELE projectile have been deduced. Finally, the theoretical results were compared with the experimental results under different working conditions, and the results were in good agreement. Therefore, the theoretical model has application value and guiding significance in the field of engineering.

Othering in Chinese official media narratives\xa0during diplomatic standoffs with the US and Japan

Based on two critical discourse analyses of Chinese media narratives on international incidents between China and the foreign ‘Other’ with an interval of nine years, this paper demonstrates continuity and consistency in Chinese official media discourse over the last decade when it concerns sensitive matters, such as sovereignty. The two case studies offered are: the 2001 diplomatic standoff with the US following the spy plane collision; and the 2010 conflict with Japan over the Chinese fishing boat collision with the Japanese coastal guard in the disputed waters of the Diaoyutai/Senkaku Islets. Using theoretical insights and methodological tools from Language Pragmatics, Critical Discourse Theory and Analysis, and Positioning Theory, these studies find identical official Chinese media practices of Othering and self-glorification. The article presents concrete examples of categorizing processes that position the actors as antagonists within a victim/aggressor framework, discursive ideological mechanisms of reification, legitimation, dramatization and generalization, and linguistic power games through the employment of assertive speech acts.

Stability in a case of motion of a paraboloid over a plane

We solve a nonlinear orbital stability problem for a periodic motion of a homogeneous paraboloid of revolution over an immovable horizontal plane in a homogeneous gravity field. The plane is assumed to be absolutely smooth, and the body–plane collisions are assumed to be absolutely elastic. In the unperturbed motion, the symmetry axis of the body is vertical, and the body itself is in translational motion with periodic collisions with the plane.

A Labeling Model Based on the Region of Movability for Point-Feature Label Placement

Automatic point-feature label placement (PFLP) is a fundamental task for map visualization. As the dominant solutions to the PFLP problem, fixed-position and slider models have been widely studied in previous research. However, the candidate labels generated with these models are set to certain fixed positions or a specified track line for sliding. Thus, the whole surrounding space of a point feature is not sufficiently used for labeling. Hence, this paper proposes a novel label model based on the region of movability, which comes from plane collision detection theory. The model defines a complete conflict-free search space for label placement. On the premise of no conflict with the point, line, and area features, the proposed model utilizes the surrounding zone of the point feature to generate candidate label positions. By combining with heuristic search method, the model achieves high-quality label placement. In addition, the flexibility of the proposed model enables placing arbitrarily shaped labels.

Oblique collisions of internal wave beams and associated resonances

AbstractQuadratic nonlinear interactions between two colliding internal gravity wave beams in a uniformly stratified fluid, and the resulting radiation of secondary beams with frequencies equal to the sum and difference of those of the primary beams, are discussed. The analysis centres on oblique collisions, involving beams that propagate in different vertical planes. The propagation directions of generated secondary beams are deduced from kinematic considerations and the use of radiation conditions, thus extending to oblique collisions previously derived selection rules for plane collisions. Using small-amplitude expansions, radiated-beam profiles at steady state are also computed in terms of the characteristics of the colliding beams. It is pointed out that, for certain oblique collision configurations, radiated beams with frequency equal to the difference of the primary frequencies have unbounded steady-state amplitude. This resonance, which has no counterpart for plane collisions, is further analysed via the solution of an initial-value problem; ignoring dissipation, the transient resonant response grows in time like ${t}^{1/ 2} $, a behaviour akin to that of forced waves at cut-off frequencies.

Strength of rapidly solidified Al–Zn–Mg alloys imposed high-velocity impact compression

Effect of impact compression on the age-hardening behavior and the mechanical properties of Mesoalite (Meso10 and Meso20) aluminum alloy was examined by means of the high-velocity plane collision between a projectile and Mesoalite by using a single powder gun. By imposing the impact compression (5 GPa) to the Meso10 and Meso20 alloys in the state of quenching after the solution heat treatment, the following age-hardening at 110°C was highly accelerated. In the impact compression (5.7 GPa) against the peak-aged Mesoalite specimens, hardness was also increased, comparing with the Mesoalite without the impact compression. XRD revealed that high strain was introduced on the specimen inside after the impact compression. Compression test results revealed that both Meso10 and Meso20 specimens imposed the impact compressive stresses more than 5 GPa after the peak-aging at 110°C showed higher compressive yield stresses, comparing with the peak-aged specimens without the impact compression. It was also shown that Meso10 and Meso20 specimens after the solution treatment, followed by the high-velocity impact compression (12 GPa) and the peak-aging treatment indicated the highest compressive yield stresses, such as 994 MPa in Meso10 and 1091 MPa in Meso20, respectively.

Discussion of “Progressive Collapse of the World Trade Center: A Simple Analysis” by K. A. Seffen

Seen’s paper presents what it calls a simple analysis for the dynamics of the World Trade Center (WTC, implicitly just the South and North Towers) collapses. He claims the responsible for the onset of collapse are now well established, that: (1) intense res created by the aircraft compromised the remaining intact columns the impact [those undamaged by the plane collision] to sustain the weight of the building above them. (2) The subsequent near free fall of these upper parts over just 1 story resulted in dynamical overloading of the undamaged columns below by a factor of over 30. Seen then goes on to develop a propagating instability model for how the re brought the Towers down. But these claimed factors are factually inaccurate. Furthermore, in analyzing the model built on these factors, ideal assumptions are made that are in disagreement with physical principles inherent in the collapses of the Towers, and yield solutions that cannot provide answers or much insight into how the Towers fell.

An Improved Physically-Based Method for Geometric Restoration of Distorted Document Images

In document digitization through camera-based systems, simple imaging setups often produce geometric distortions in the resultant 2D images because of the non-planar geometric shapes of certain documents such as thick bound books, rolled, folded or crumpled materials, etc. Previous works have demonstrated that arbitrary warped documents can be successfully restored by flattening a 3D scan of the document. These approaches use physically-based or relaxation-based techniques in their flattening process. While this has been demonstrated to be effective in rectifying the image content and improving OCR, these previous approaches have several limitations in terms of speed and stability. In this paper, we propose a distance-based penalty metric to replace the mass-spring model and introduce additional bending resistance and drag forces to improve the efficiency of the existing approaches. The use of Verlet integration and special plane collision handling schemes also help to achieve better stability without sacrificing efficiency. Experiments on various document images captured from books, brochures and historical documents with arbitrary warpings have demonstrated large improvements over the existing approaches in terms of stability and efficiency.

“Holding Nationalist Flags Against Red Flags” —Anti-American Icons in Contemporary China and their Reconstruction by the Public (1999–2003)

Focusing on the construction and reconstruction process of anti-American icons in contemporary China, this paper compares the patterns of interactions between the Chinese government, intellectuals and general public during four events centering on China-US relations: the 1999 Belgrade embassy bombing, the early 2001 plane collision incident, the September 11 attacks, and the 2003 war in Iraq. The article suggests that the proliferation of anti-American icons in China does not only point towards the existence of anti-foreign ideologies. It is also a channel for different players in China to advance their personal and group interests. As long as tolerance from Beijing is signalled, much nationalist rhetoric is a coded way of directing limited dissent at the Chinese state itself, but how exactly the Chinese public hold the “nationalist flags” — which is allowed by the party–state — against the “red flags” of the same regime remains relatively unexplored. Filling up such an intellectual vacuum is the central focus of this paper.

Moraliseringen af seeren

Lilie Chouliaraki: The Moralisation of the Spectator. On the September 11th live footage
 
 In this paper, I discuss extracts of the September 11th live footage on television from the vantage point of discourse, that is of how the reported event “comes to mean“, how it becomes intelligible through television’s meaning-making operations. Specifically, I study the mediation of the September 11th as a mediation of “distant suffering“, drawing upon the work of Luc Boltanski (1999) on “morality, media and politics“. My aim is to identify the ways in which the September 11th television spectacle engages the affective potential of the spectator and evokes a specific disposition to act upon the suffering – that is, to act politically. My perspective on the September 11th thus concerns the televisual mediation of distant suffering and its moralising effects on the spectator. First, I introduce the problematic of representing distant suffering in terms of, what Boltanski calls, a “politics of pity“ – a politics that aims to resolve the Spacetime dimensions of mediation in order to establish a sense of “proximity“ to the events and, so, engage the spectator emotionally and ethically. Second, I contrast three different modes (or “topics“) of representing suffering, by reference to three live footage extracts from the Danish national television channel (DR): street shots of Manhattan, just after the Twin Towers’ collapse; the summary of the day events, with shots from the second plane collision and President Bush’s first public statement; a long shot of the Manhattan skyline burning. 
 I describe each “topic“ in terms of its Spacetime dimensions, its distinctive semiotic elements, and the affective mode and moral horizon it opens up for the spectator. In concluding, I briefly touch upon implications for the “moralisation“ of the spectator, involved in the September 11th “topics“ of suffering.

Publisher's Note: M theory model of a big crunch/big bang transition [Phys. Rev. D70, 106004 (2004)

We consider a picture in which the transition from a big crunch to a big bang corresponds to the collision of two empty orbifold planes approaching each other at a constant non-relativistic speed in a locally flat background space-time, a situation relevant to recently proposed cosmological models. We show that $p$-brane states which wind around the extra dimension propagate smoothly and unambiguously across the orbifold plane collision. In particular we calculate the quantum mechanical production of winding M2-branes extending from one orbifold to the other. We find that the resulting density is finite and that the resulting gravitational back-reaction is small. These winding states, which include the string theory graviton, can be propagated smoothly across the transition using a perturbative expansion in the membrane tension, an expansion which from the point of view of string theory is an expansion in {\it inverse} powers of $\alpha'$. We argue that interactions should be well-behaved because the string coupling tends to zero at the crunch. The production of massive Kaluza-Klein states should also be exponentially suppressed for small collision speeds. We contrast this good behavior with that found in previous studies of strings in Lorentzian orbifolds.

An Analysis of a 1-Dimensional Plane Collision of Continuous Bodies

An Analysis of a 1-Dimensional Plane Collision of Continuous Bodies

M theory model of a big crunch/big bang transition

We consider a picture in which the transition from a big crunch to a big bang corresponds to the collision of two empty orbifold planes approaching each other at a constant nonrelativistic speed in a locally flat background space-time, a situation relevant to recently proposed cosmological models. We show that $p$-brane states which wind around the extra dimension propagate smoothly and unambiguously across the orbifold plane collision. In particular we calculate the quantum mechanical production of winding M2-branes extending from one orbifold to the other. We find that the resulting density is finite and that the resulting gravitational backreaction is small. These winding states, which include the string theory graviton, can be propagated smoothly across the transition using a perturbative expansion in the membrane tension, an expansion which from the point of view of string theory is an expansion in inverse powers of ${\ensuremath{\alpha}}^{\ensuremath{'}}$. The conventional description of a crunch based on Einstein general relativity, involving Kasner or mixmaster behavior is misleading, we argue, because general relativity is only the leading order approximation to string theory in an expansion in positive powers of ${\ensuremath{\alpha}}^{\ensuremath{'}}$. In contrast, in the M theory setup we argue that interactions should be well behaved because of the smooth evolution of the fields combined with the fact that the string coupling tends to zero at the crunch. The production of massive Kaluza-Klein states should also be exponentially suppressed for small collision speeds. We contrast this good behavior with that found in previous studies of strings in Lorentzian orbifolds.

Watching 11 September: The Politics of Pity

In this article, I discuss extracts of television footage from the vantage point of discourse: how the reported event ‘comes to mean’, how it becomes intelligible through television’s meaning-making operations. Specifically, I study the mediation of the 11 September event as one of distant suffering, drawing upon the work of Luc Boltanski (1999) on morality, media and politics. My aim is to identify the ways in which the television spectacle engages the affective potential of the spectator and evokes a specific disposition to act upon the suffering – thus, its moralizing effects on the spectator. First, I introduce a ‘politics of pity’, a politics that aims to resolve the space–time dimensions of mediation in order to establish a sense of ‘proximity’ to the events and so engage the spectator. Second, I contrast three different modes (or ‘topics’) of representing suffering, by reference to three extracts from the Danish national television channel: street shots of Manhattan, just after the collapse of the Twin Towers; the summary of the day’s events, with shots from the second plane collision and President Bush’s first public statement; and a long shot of the Manhattan skyline burning. I describe each ‘topic’ in terms of its space–time dimensions, its distinctive semiotic elements, and the affective and moral horizons it opens up for the spectator.

United States–China Plane Collision Negotiation

On April 1, 2000 an American surveillance plane and a Chinese fighter plane collided off the coast of China. The Chinese pilot parachuted out of his aircraft but was presumed dead; his body was not found. The U.S. plane made an emergency landing at a Chinese military airfield without receiving permission. China thus had possession of the U.S. plane and crew. China said that the U.S. was responsible for the crash and demanded an apology. The U.S. expressed “regret” over the collision but declared it had no apology to give as the fault lay with the Chinese pilot. On April 10 with negotiation between the two countries remaining deadlocked, the author considered the problem in the Evolutionary Systems Design (ESD) framework. The article discusses the author's analysis and solution, his efforts to implement it, and the agreed solution announced by the U.S. and China on April 11.

Plane Collision Problem for Two Identical Elastic Parabolic Bodies—Direct Central Impact

A direct central collision of two identical infinite cylindrical bodies is studied. A nonstationary plane elastic problem is solved. The variable boundary of the contact area is determined. A mixed boundary problem is formulated. Its solution is represented by Fourier series. An infinite system of Volterra equations of the second kind for the unknown expansion coefficients is derived by satisfying boundary conditions. The basic characteristics of the collision process are determined numerically depending on the curvature of the frontal surface of the bodies

An Analysis of a 1-Dimensional Plane Collision of Continuous Bodies (1st Report, A Theory)

Many investigations have been done on dynamic behavior of solids or hypervelocity behavior of condensed matters. However, general formulas between two collision velocities and material constants et al. before collision and physical quantities of two continuous bodies immediately after collision have not been yet sufficiently established when two continuous bodies collide each other at any collision velocity including two cases above mentioned. In the present paper, it is newly shown that relational formulas among physical quantities produced by plane collision are expressed in terms of two collision velocities, material constants and the slope of the relation between propagation speed of precursor and particle velocity of the compressive stress wave. And, theoretical equations are derived based on the proposed general formulas in a few special cases and considered. Those approximate formulas and applicable conditions are given.

An Analysis of a 1-Dimensional Plane Collision of Continuous Bodies (2nd Report, Comparison of a Theory with Experiments)

A general formula in a 1-dimensional plane collision was established in an another report in which any physical quantities in both bodies immediately after collision are expressed in terms of collision velocities, material constants and coefficients before collision when both bodies collide with any collision velocities. In the present paper, the equations in the calculation to obtain any physical quantity are derived from the proposed general formula when two bodies are of the same material and the same cross-sectional area and both bodies collide each other and then shock wave is produced in the target at rest. And calculated values based on the derived theory are compared with experiments of the relation between shock pressure and relative volume. Consequently, both theory and experiment agree precisely, the proposed general formula in a 1-dimensional plane collision is proved to be valid also in the case of hypervelocity collision.

Culture Clash? Apologies East and West

Following the 1 April 2001 plane collision over the South China Seas, China and the United States engaged in two weeks of intensive 'apology diplomacy'. What role did culture play in these events? Drawing on experimental findings in social and cross-cultural psychology, we argue against the pundits that essentialized cultural difference--and against those who denied that culture matters. Instead, we maintain that both cultural differences and cultural commonalties played a significant role in Sino-American apology diplomacy.