The validity of an experiment testing the influence of acceleration on time dilation using a rotating Mössbauer absorber and a Synchrotron Mössbauer Source

Three experiments are reviewed, performed (in 2014–2016) at ID18 of ESRF to measure the influence of acceleration on time dilation by measuring the relative shift between the absorption lines of two states of the same rotating absorber with accelerations anti-parallel and parallel to the incident beam. Statistically significant data for rotation frequencies up to 510 Hz in both directions of rotation were collected. For each run with high rotation, a stable statistically significant `vibration-free' relative shift between the absorption lines of the two states was measured. This may indicate the influence of acceleration on time dilation. However, the measured relative shift was also affected by the use of a slit necessary to focus the beam to the axis of rotation to a focal spot of sub-micrometre size. The introduction of the slit broke the symmetry in the absorption lines due to the nuclear lighthouse effect and affected the measured relative shift, preventing to claim conclusively the influence of acceleration on time dilation. Assuming that this loss of symmetry is of first order, the zero value of the relative shift, corrected for this loss, falls always within the experimental error limits, as predicted by Einstein's clock hypothesis. The requirements and an indispensable plan for a conclusive experiment, once the improved technology becomes available, is presented. This will be useful to future experimentalists wishing to pursue this experiment or a related rotor experiment involving a Mössbauer absorber and a synchrotron Mössbauer source.

China and Political Governance in Africa

China’s engagement in Africa since around 2000 has been exponential, and Beijing is now perhaps the major player on the continent. With this has come criticism, mainly but not exclusively from the West, which has berated China for turning a blind eye to malgovernance. Initially, China sought to pretend that it was only in Africa for economic reasons and that politics were irrelevant. However, as China’s stake in different African countries developed, Beijing was forced to acknowledge that governance was indeed a factor that needed consideration. This realization was perhaps crystallized around the situation in Sudan. A relative shift in China’s position was hence observed. Under Xi Jinping, however, a newly confident China has been promoting its own definitions of governance, something that enjoys broad support among many African leaders. A clash of definitions as to what constitutes governance and development between China and the West is now quite apparent.

CHANGE DETECTION IN REMOTE SENSING IMAGES USING CONDITIONAL ADVERSARIAL NETWORKS

We present a method for change detection in images using Conditional Adversarial Network approach. The original network architecture based on pix2pix is proposed and evaluated for difference map creation. The paper address three types of experiments: change detection in synthetic images without objects relative shift, change detection in synthetic images with small relative shift of objects, and change detection in real season-varying remote sensing images.

Modulation of the carrier mobility enhancement in Si/Ge core–shell nanowires under different interface confinements

Relative shift of carrier mobility vs. self-equilibrium strain in SiNWs.

Broadband observations of pulsar profiles and frequency dependent DMs

The aim of our project is to search for ways to best extract information on pulsar profiles and the interstellar medium (ISM), using the wide frequency bands that are typical of radio telescopes today. Pulsar profiles typically show a strong dependence on frequency. This depends both on the intrinsic radio emission mechanism, and the interaction of the radio waves with the ISM that lies between the pulsars and our detectors on Earth, due mostly to the effects of dispersion and scattering. In this work, we make use of radio pulsar beam models from the existing literature, to generate simulated pulse profiles, observed across various bands (centre frequencies and bandwidths), for each beam model. For all the chosen geometric parameters of the pulsar beam, observed in any frequency band, the simulated profiles manifest a relative shift in phase in their observed components, as a result of the intrinsic profile evolution. This relative shift in phase could be interpreted as an additional component to the ISM induced dispersion measure (DM). This additional DM component due to profile evolution is frequency dependent. We discuss the systematics introduced to pulsar data due to this effect.

Advances in testing the effect of acceleration on time dilation using a synchrotron Mössbauer source

New results, additional techniques and know-how acquired, developed and employed in a recent HC-1898 experiment at the Nuclear Resonance Beamline ID18 of ESRF are presented, in the quest to explore the acceleration effect on time dilation. Using the specially modified Synchrotron Mössbauer Source and KB-optics together with a rotating single-line semicircular Mössbauer absorber on the rim of a specially designed rotating disk, the aim was to measure the relative spectral shift between the spectra of two states when the acceleration of the absorber is anti-parallel and parallel to the source. A control system was used for the first time and a method to quantify the effects of non-random vibrations on the spectral shift was developed. For several runs where the effect of these vibrations was negligible, a stable statistically significant non-zero relative shift was observed. This suggests the influence of acceleration on time.

The Investigation of a Novel Large-Strain Sensor Based on a Dual Capacitive Structure

In this paper, a novel large-strain sensor based on a dual planar capacitive structure has been developed. It has the capacity of large-strain measurement up to 200,000 με (0.2 ε). The change in strain causes a measurable transformation in the capacitance of the sensor by relative shift of the overlap area between two capacitive plates, one fixed (i.e. fixed plate) and the other one movable (i.e. movable plate), and is thus converted into a voltage signal by a read-out circuit module. The dual capacitor structure was designed for increasing the initial capacitance and improving the resolution of sensors compared with a single capacitor structure. The experimental results showed that the sensor had a linearity of 2.29% full scale (FS), a hysteresis error of 1.146%FS, repeatability of 0.226%FS and a resolution of 0.5%FS, suggesting excellent performance of the sensor.