A Discussion on Sea Level Rise, Rate Ad Acceleration. Venice as a Case Study

The paper discusses the equations used to represent the sea level rise, and in particular the second-order polynomial, generally preferred because its second-order coefficient is related to acceleration. The long series of the sea level rise in Venice offers a particularly useful case study from 1350 to 2016, because it may be equally represented, at the same level of explained variance, by an exponential or a quadratic best-fit equation. The first-order and the second-order derivatives respectively represent the rate and the acceleration of sea level rise. The derivatives obtained from the second-order polynomial representation generate a linear rate and a constant acceleration, while those derived from an exponential preserve the exponential character. The two rates (i.e. from the quadratic and the exponential equations), and the two accelerations are characterized by different equations and different plots, but their average values are the same. The second-order polynomial with constant acceleration is in line with a climate with constant forcing factors; the exponential with a dynamic condition with increasing forcing factors and acceleration. Mathematical formulae and physical consequences are discussed in the framework of different scenarios. Finally, the trend-forecast extrapolation is discussed and applied to the case study of Venice. It is shown that, in the most optimistic assumption of forcing increasing at unchanged rate, the sea level in Venice will rise by 33.8 ± 4 cm over this century, that may be compared to the 31 cm of the similar, most optimistic prediction made by IPCC for business-as-usual.

Lower-limb kinematics and kinetics during continuously varying human locomotion

Human locomotion involves continuously variable activities including walking, running, and stair climbing over a range of speeds and inclinations as well as sit-stand, walk-run, and walk-stairs transitions. Understanding the kinematics and kinetics of the lower limbs during continuously varying locomotion is fundamental to developing robotic prostheses and exoskeletons that assist in community ambulation. However, available datasets on human locomotion neglect transitions between activities and/or continuous variations in speed and inclination during these activities. This data paper reports a new dataset that includes the lower-limb kinematics and kinetics of ten able-bodied participants walking at multiple inclines (±0°; 5° and 10°) and speeds (0.8 m/s; 1 m/s; 1.2 m/s), running at multiple speeds (1.8 m/s; 2 m/s; 2.2 m/s and 2.4 m/s), walking and running with constant acceleration (±0.2; 0.5), and stair ascent/descent with multiple stair inclines (20°; 25°; 30° and 35°). This dataset also includes sit-stand transitions, walk-run transitions, and walk-stairs transitions. Data were recorded by a Vicon motion capture system and, for applicable tasks, a Bertec instrumented treadmill.

From the Galileo Free Fall String to the Principle of Equivalence

We consider the string with the length l, the left end and the right end of which is non relativistically accelerated by the constant acceleration a. We calculate the motion of such string and then the motion of the Galileo free fall string in gravity. The solutions are not identical. So, we distinguish between noninertial field and the gravity field and we discuss the principle of equivalence. In conclusion we suggest to drop charged objects from the very high tower Burj Khalifa in order to say crucial words on the principle of equivalence.

Analysis of the Deep Sea Mining Pipe Transverse Vibration Characteristics Based on Finite Element Method

This paper analyzes the transverse vibration laws of 5000 m ladder-shaped mining pipe under different towing velocities and accelerations in the ocean, thinking of the pipe as the beam model, discretized based on the FEM. The algorithm is used to solve the problem to obtain the transverse vibration law. The research shows that the mining pipe overall transverse vibration trend decreases first and then increases, the minimum vibration value occurs at 3000 m, and the maximum occurs at the top. Increasing the towing velocity, acceleration, and ore bin weight will increase the transverse vibration value. The vibration intensity produced by the same acceleration in the constant acceleration and deceleration stages is different, and the damping effect after adding the same damping is also different. In the range of 0.01 m/s2–0.1 m/s2, the vibration reduction effect after adding damping in the constant deceleration stage is more significant, and in the range of 0.1 m/s2-0.2 m/s2, the vibration reduction effect after adding damping in the constant acceleration stage is more significant. In the stage of the constant acceleration or deceleration, when adding the same damping, the vibration intensity generated by the large acceleration is still far greater than the vibration intensity generated by the small acceleration, so the mining ship should keep the small acceleration for towing motion.

Big Bang Theory based on Hubble’s constant

The experimental relations between the speeds of galaxies and their corresponding separations from the Earth are discussed in some detail. It is pointed out that Hubble’s Constant, which indicates that the speeds and separations have the same constant ratio for every known galaxy, can be combined with well-known relationships for objects under the influence of constant acceleration to give some concrete predictions of how these quantities vary with time. It is found according to this analysis that the acceleration of each galaxy is directly proportional to its speed, for example. This value is the net result of the continuous competition between gravitational forces and the inertial forces still operative since the Big Bang explosion. Its value is extremely small, equal to only 1.17x10-10 ft/s2 for the Hydra galaxy, for example, which moves at a speed of 38,000 mi/s. Most importantly, the indication is that is that the inertial forces are constantly winning out over the gravitational forces for each galaxy. The resulting equations also indicate that the speed of any galaxy varies in direct proportion to the time Δt which has elapsed since the origin of the universe (Big Bang explosion), while its distance from the Earth varies as the square of this elapsed time. On this basis, it is concluded that Hubble’s Constant itself varies in direct proportion to Δt and thus acts as a “clock of the universe.” More generally, the conclusion from this analysis is that the universe is open and continues to expand outward at an ever increasing rate

Big Bang Theory based on Hubble’s constant

The experimental relations between the speeds of galaxies and their corresponding separations from the Earth are discussed in some detail. It is pointed out that Hubble’s Constant, which indicates that the speeds and separations have the same constant ratio for every known galaxy, can be combined with well-known relationships for objects under the influence of constant acceleration to give some concrete predictions of how these quantities vary with time. It is found according to this analysis that the acceleration of each galaxy is directly proportional to its speed, for example. This value is the net result of the continuous competition between gravitational forces and the inertial forces still operative since the Big Bang explosion. Its value is extremely small, equal to only 1.17x10-10 ft/s2 for the Hydra galaxy, for example, which moves at a speed of 38,000 mi/s. Most importantly, the indication is that is that the inertial forces are constantly winning out over the gravitational forces for each galaxy. The resulting equations also indicate that the speed of any galaxy varies in direct proportion to the time Δt which has elapsed since the origin of the universe (Big Bang explosion), while its distance from the Earth varies as the square of this elapsed time. On this basis, it is concluded that Hubble’s Constant itself varies in direct proportion to Δt and thus acts as a “clock of the universe.” More generally, the conclusion from this analysis is that the universe is open and continues to expand outward at an ever increasing rate

The Uniformly Accelerated String and the Bell Spaceship Paradox

We consider the string with the length l, the left end and the right end of which is non-relativistically and then relativistically accelerated by the constant acceleration a. We calculate the motion of the string with no intercalation of the Fitzgerald contraction of the string. We consider also the Bell spaceship paradox. The Bell paradox and our problem is in the relation with the Lorentz contraction in the Cherenkov effect (Pardy, 1997) realized by the carbon dumbbell moving in the LHC or ILC (Pardy, 2008). The Lorentz contraction and Langevin twin paradox (Pardy, 1969) is interpreted as the Fock measurement procedure (Fock, 1964;).

Relativistic coordinates’ transformations of accelerating reference frames. A new approach

In this paper, Lorentz-type coordinates’ transformations are proposed to connect the coordinates of an accelerating reference frame with the coordinates of a fixed one. Next, these transformations are applied to accelerating frames of constant acceleration. Finally, the Lorentz-type transformations are applied to the twin paradox, in an attempt to describe how the acceleration affects this phenomenon.