Papers by Keyword: Angular Momentum

Abstract: Abstract. The 30 nm wide quantum wells on a 4x4 mm2 piece of GaAs/AlGaAs are formed when the layers of GaAs are deposited on AlGaAs films. The two-dimensional density of electrons is 3x1011 cm-2 and the mobility is 32x106 cm2/Vs. In such a sample the Hall resistivity as a function of magnetic field is not a linear function. Hence a suitable theory to understand the Hall effect is formulated. We find that there are phase transitions as a function of temperature. There are lots of fractions of charge which are explained on the basis of spin and orbital angular momentum of the electron. The nano meter size films of graphite also show that the Hall resistivity is non-linear and shows steps as a function of magnetic field. We make an effort to understand the steps in the Hall effect resistivity of graphite with quantum wells formed on the surface. It is found that the fractions are in four categories, (i) the principal fractions which are determined by spin and orbital angular momenta, (ii) the resonances which occur at the difference between two values such as =1-2, (iii) two-particle states which occur at the sum of the two frequencies and (iv) there are clusters of electrons localized in some areas of the sample. The spin in the clusters is polarized so that it becomes NS which is not 1/2 but depends on the number N, of electrons in a cluster.

Abstract: We present a study of the feasibility of controlling the pitch angle of a high velocity ground vehicle in ballistic phase by accelerating or decelerating its wheels. The vehicle performed several jumps, and various wheel acceleration commands were sent to it while it was airborne. Images were recorded using a high-speed video camera, and the trajectories of markers placed on the vehicle were analyzed in order to measure the relationship between the changes in angular velocities of the chassis and the wheels. It appeared that it was possible to achieve pitch righting through the modification of the angular velocities of the wheels with adequate performance, thus opening the road towards automated control of pitch, then later yaw and roll angles.

Abstract: When the power transmission line is covered with ice and snow in the winter, the galloping of power line often happens. A new type of damper used for preventing galloping of the electric power transmission line has been put forward and received patent license of China. The damper like fan blades, which can rotate about the axes of the power line at 360°, is fixed on the overhead power line. It hangs on the line when there is no wind. The blade rotates at high speed in the plane vertical to wind when there is wind, which results in a gyroscope. The theorem of angular momentum of a gyroscope is used in the design of the damper. Model tests of this kind of damper have been carried out and the results show that it is successful in preventing galloping of the cable model.

Abstract: Cosmic censorship!: black hole wrapped up by its entropy and hidden by its event horizon. In this paper, we postulate a metric to solve the Einstein equations of general relativity, which predicts the thermodynamic behavior of a gigantic mass that collapses to a black hole; taking into account the third law of thermodynamics that states that neither physical process can produce a naked singularity. However, under certain conditions, the model allows to evident violation to the cosmic censorship, exposing the hole nakedness. During the collapse of the hole, quantum effects appear: the area decrease and radiation produced has a high entropy, so that increases total entropy and expose the presence of the hole, while the appearance of the event horizon hide the singularity of the exterior gazes. It is verified that in certain circumstances, the model predicts that the hole mass is bigger than its angular momentum; and in all circumstances, this predicts an hole with enormous superficial graveness that satisfy a relationship of the three parameters that describe the hole (mass, charge and angular momentum); factors all indicative that the singularity is not naked. Then, there are no apparent horizons in accord with cosmic censorship conjecture. Even though the surface gravity of the hole prevents destroying its horizon wrapping singularity, there exists evidence of this singularity by the results of the spin-mass relationship and the escape velocity obtained. The lost information and the slow rate of rotation of the semi-major axis of the mass (dragging space and time around itself as it rotates), agree with Einstein's prediction, show the transport of energy through heat and mass transfer, which were measured by entropy of the hole by means of coordinated semi-spherical that include the different types of intrinsic energy to the process of radiation of the hole event horizon.