PanCam: the ‘science eyes’ of the Rosalind Franklin (ExoMars 2022) rover

<p>The scientific objectives of the ExoMars Rosalind Franklin rover [1] are designed to answer several key questions in the search for life on Mars. In particular, the unique subsurface drill will address some of these questions for the first time, such as the possible existence and stability of sub-surface organics. PanCam [2] will establish the surface geological and morphological context for the mission, working in collaboration with other context instruments. Here, we describe the PanCam scientific objectives in geology, atmospheric science and 3D vision. We discuss the design of PanCam, which includes a stereo pair of Wide Angle Cameras (WACs), each of which has an 11 position filter wheel, and a High Resolution Camera (HRC) for high resolution investigations of rock texture at a distance. The cameras and electronics are housed in an optical bench that provides the mechanical interface to the rover mast and a planetary protection barrier.  The electronic interface is via the PanCam Interface Unit (PIU), and power conditioning is via a DC-DC converter. PanCam also includes a calibration target mounted on the rover deck for radiometric calibration, fiducial markers for geometric calibration and a rover inspection mirror. Recent simulations [3] show the view from PanCam, the ‘science eyes’ of the Rosalind Franklin rover.</p> <p><strong>References:</strong></p> <p>[1] Vago, J.L., F. Westall, A.J. Coates, et al., Habitability on Early Mars and the Search for Biosignatures with the ExoMars Rover, <em>Astrobiology</em>, 17(6-7), 471-510, doi:10.1089/ast.2016.1533, Jul 2017.</p> <p>[2] Coates, A.J., R. Jaumann, A.D. Griffiths, et al., The PanCam instrument for the ExoMars rover, <em>Astrobiology</em>, 17 (6-7), 511-541, doi: 10.1089/ast.2016.1548, Jul 2017.</p> <p>[3] Miles, H.C., M.D. Gunn and A.J. Coates, Seeing through the ‘Science Eyes’ of the ExoMars Rover, IEEE Computer Graphics & Applications, Applications Department, 40, 71-81, doi: 10.1109/MCG.2020.2970796, Mar-Apr 2020.</p>

Magnetotherapy for group treatment

The advantage of complex magnetic therapy devices (MTD) is the possibility of forming magnetic fields that are complexly distributed in space and time, which provides focused treatment of a specific disease, taking into account the individual characteristics of the patient. To increase the throughput of the physiotherapy room, a solution is proposed for organizing the simultaneous treatment of several patients using one device. Within the framework of the study, an approach based on the use of a reconfigurable system was considered, in accordance with which the MTD is built in the form of a set of the same type of intelligent magnetotherapy cells (MTC) and a central control module. This structure is the basis of the hardware component of the MTC, designed for group magnetotherapy. The conceptual model of the MTC includes the following elements: a local control unit, a local interface module, a memory unit, an identification unit, a power interface unit, an inductor unit, and a control unit. The specified composition of MTC components, on the one hand, provides the possibility of autonomous operation of the cell, and on the other hand, it supports centralized control, diagnostics, and simultaneous start and stop of the magnetic field generation process. The main idea of the method for conducting group magnetotherapy is the generation by the central control module of a unified magnetotherapy technique formed on the basis of magnetotherapy techniques, each of which is selected taking into account the required individual treatment of a particular patient. Conventionally, the aggregate of MTC is divided into groups – field-forming systems, each of which is used to treat an individual patient. Each MFT operates in an autonomous mode, which is achieved due to the presence of a local control unit in the cell, which, through the local interface module, receives the data necessary for carrying out a magnetotherapy procedure, and after a group launch independently generates and controls the acting magnetic field. In addition, the analysis of the proposed solution is carried out in the work, as well as issues of possible technical implementation are considered. Thus, the advantage, determined by the autonomous mode of operation of the MTC, allows you to set the duration of the operation of each cell within the framework of the current magnetotherapy procedure, individually. As a result, at the end of a separate magnetotherapy procedure, the MTCs that were used for this procedure can be used to create a field-forming system for treating the next patient, without the need to wait for the end of all active magnetotherapy procedures. In the practical construction of an MTD intended for group magnetotherapy, it is recommended to use microcontrollers as control units, motor drivers as a power interface unit, and specialized DS2411 type microcircuits as an identification unit. One of the possible implementations can be a solution based on an Internet server, then it is recommended to choose Ethernet as the interface, and it is preferable to use the IP address of the MTC as the MTC identifier. The ideas and solutions considered in the framework of the task of implementing group magnetotherapy can be generalized and used for other physical fields used in physiotherapy.

Study on Macroscopic and Mesoscopic Mechanical Behavior of CSG based on Inversion of Mesoscopic Material Parameters

Cement Sand and Gravel (CSG) is a low-cost, environment-friendly composite material mixed of unscreened aggregate, cement, fly ash and water, and its properties differ from ordinary concrete due to different aggregate characteristics. In order to investigate the effect of aggregate characteristics on the mechanical behavior of CSG, this paper used numerical simulation method to divide the CSG into aggregate unit, cement mortar unit and interface unit at the mesoscopic level and randomly generate aggregate, then used laboratory uniaxial compression test results to inverse the said mesoscopic component parameters, and finally verified the rationality of mesoscopic numerical simulation. Based on the inversed parameters, the numerical simulation test of different aggregate grading was carried out and analyzed. The results showed that: (1) From the perspective of macroscopic mechanical properties, as the sand ratio increased, the aggregate occupancy and the peak stress decreased; under the same aggregate occupancy (the same sand ratio), the stress peak became higher with the improvement of aggregate grading (aggregates of small particle size increased); (2) At the mesoscopic level, the crack of CSG usually appeared on the interface and around the aggregate; the smaller the sand ratio was, the higher the aggregate occupancy was, the more obvious the stress concentration was, and the earlier the cracking of the test piece was, but there were many aggregates, so the eventual failure time was delayed. These research results can provide theoretical basis for engineering design and construction.

Design of a Pixelated Imaging System for Fast Neutron Sources

Imaging detectors that use X-ray radiation and pulsed neutron sources have increased in sophistication in recent years due to the use of solid-state detectors. A key method for neutron detection is the nuclear activation of materials by neutrons. Neutron activation can generate radionuclides whose decay produces secondary particle emission that can be detected without interference from the X-rays and other prompt radiation sources and offers advantages over neutrons detection using scintillators. In this paper, we present the design of an imaging system for fast neutron sources. The imaging system utilizes a microcontroller network that communicates using a modified SPI protocol. This network communicates with an interface unit and passes an image to a personal computer. A computer program has been developed to reconstruct the image.