Concentration-dependent diffusivity and anomalous diffusion: A magnetic resonance imaging study of water ingress in porous zeolite

Magnetic resonance imaging is employed to study water ingress in fine zeolite powders compacted by high pressure. The experimental conditions are chosen such that the applicability of Boltzmann's transformation of the one-dimensional diffusion equation is approximately satisfied. The measured moisture profiles indicate subdiffusive behavior with a spatiotemporal scaling variable eta=x/t(gamma/2) (0 <gamma < 1). A time-fractional diffusion equation model of anomalous diffusion is adopted to analyze the data, and an expression that yields the moisture dependence of the generalized diffusivity is derived and applied to our measured profiles. In spite of the differences between systems exhibiting different values of gamma a striking similarity in the moisture dependence of the diffusivity is apparent. This suggests that the model addresses the underlying physical processes involved in water transport.731

Measuring the Galactic Cosmic Ray Flux with the LISA Pathfinder Radiation Monitor

Test mass charging caused by cosmic rays will be a significant source of acceleration noise for space-based gravitational wave detectors like LISA. Operating between December 2015 and July 2017, the technology demonstration mission LISA Pathfinder included a bespoke monitor to help characterise the relationship between test mass charging and the local radiation environment. The radiation monitor made in situ measurements of the cosmic ray flux while also providing information about its energy spectrum. We describe the monitor and present measurements which show a gradual 40% increase in count rate coinciding with the declining phase of the solar cycle. Modulations of up to 10% were also observed with periods of 13 and 26 days that are associated with co-rotating interaction regions and heliospheric current sheet crossings. These variations in the flux above the monitor detection threshold (approximately 70 MeV) are shown to be coherent with measurements made by the IREM monitor on-board the Earth orbiting INTEGRAL spacecraft. Finally we use the measured deposited energy spectra, in combination with a GEANT4 model, to estimate the galactic cosmic ray differential energy spectrum over the course of the mission

Development of an autopilot system for fishing boats

Autopilot system is a navigation methodology that can he introduced to local fishing industry in order to improve the productivity. This project was carried out with the purpose of supplying a tow cost autopilot system for local fishermen. In this paper, it addresses the tracking problem for an Autopilot boat using a controller, namely yaw moment (yaw torque control) taking environmental disturbances also into account. A simple slate feedback control law is developed Simulation results are presented in the form of graphical method . Also designing of the mechanical and electronic parts of the system is addressed here. The input and output components of the system and their functionality are described. Further describes the communication methods that used to interface microcontroller to other electronic components like GPS, compass. Also the methods that used to control the output devices like DC motors Requirement of designing a servo controller for rudder movement is a major task of the project Drive mechanism of the rudder and methods used to get feedback is explained I he importance of designing user interface of the system is also addressed. Programming the microcontrollers is done using C language. CSS compiler To snitch between autopilot mode and manual mode two solenoid operated directional control valves are used . it present autopilot system is mounted on a platform and can be used to demonstrate how the system works