11 research outputs found

    Feasibility and reliability of sequential logic with gene regulatory networks

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    Gene regulatory networks exhibiting Boolean behaviour, e.g. AND, OR or XOR, have been routinely designed for years. However, achieving more sophisticated functions, such as control or computation, usually requires sequential circuits or so-called state machines. For such a circuit, outputs depend both on inputs and the current state of the system. Although it is still possible to design such circuits by analogy with digital electronics, some particularities of biology make the task trickier. The impact of two of them, namely the stochasticity of biological processes and the inhomogeneity in the response of regulation mechanisms, are assessed in this paper. Numerical simulations performed in two use cases point out high risks of malfunctions even for designed GRNs functional from a theoretical point of view. Several solutions to improve reliability of such systems are also discussed

    The deformable secondary mirror of VLT: final electro-mechanical and optical acceptance test results

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    The Deformable Secondary Mirror (DSM) for the VLT ended the stand-alone electro-mechanical and optical acceptance process, entering the test phase as part of the Adaptive Optics Facility (AOF) at the ESO Headquarter (Garching). The VLT-DSM currently represents the most advanced already-built large-format deformable mirror with its 1170 voice-coil actuators and its internal metrology based on co-located capacitive sensors to control the shape of the 1.12m-diameter 2mm-thick convex shell. The present paper reports the final results of the electro-mechanical and optical characterization of the DSM executed in a collaborative effort by the DSM manufacturing companies (Microgate s.r.l. and A.D.S. International s.r.l.), INAF-Osservatorio Astrofisico di Arcetri and ESO. The electro-mechanical acceptance tests have been performed in the company premises and their main purpose was the dynamical characterization of the internal control loop response and the calibration of the system data that are needed for its optimization. The optical acceptance tests have been performed at ESO (Garching) using the ASSIST optical test facility. The main purpose of the tests are the characterization of the optical shell flattening residuals, the corresponding calibration of flattening commands, the optical calibration of the capacitive sensors and the optical calibration of the mirror influence functions

    Results of CEA Tests of SARAF Cavities Prototypes

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    International audienceCEA is committed to delivering a Medium Energy Beam Transfer line and a superconducting linac (SCL) for SARAF accelerator in order to accelerate 5mA beam of either protons to 35 MeV or deuterons to 40 MeV. The SCL consists in 4 cryomodules. The first two cryomodules host 6 & 7 half-wave resonator (HWR) low beta cavities (β = 0.09) at 176 MHz, and the last two crymodules host 7 HWR medium beta cavities (β = 0.18). The low beta prototype was qualified, the medium beta is being qualified. The results of the RF tests will be presented in this poster

    Results of CEA Tests of SARAF Couplers Prototypes

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    International audienceCEA is committed to delivering a Medium Energy Beam Transfer line and a superconducting linac (SCL) for SARAF accelerator in order to accelerate 5 mA beam of either protons from 1.3 MeV to 35 MeV or deuterons from 2.6 MeV to 40 MeV. The SCL consists in 4 cryomodules. The first two cryomodules host 6 and 7 half-wave resonator (HWR) low beta cavities (β = 0.09) at 176 MHz. The last two identical cryomodule will host 7 HWR high-beta cavities (β = 0.18) at 176 MHz. The maximal required power to be transmitted to the beam is 11.4 kW for high-beta cavity couplers. This document presents the results of the coupler tests and conditioning

    The M4 adaptive unit for the E-ELT

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    International audienceCilas proposes a M4 adaptive mirror (M4AM) that corrects the atmospheric turbulence at high frequencies and residual tip-tilt and defocus due to telescope vibrations by using piezostack actuators. The design presents a matrix of nearly 7000 actuators (hexagonal geometry, spacing equal to 29 mm) leading to a fitting error simulated by Onera reaching the fitting error goal. The mirror is held by a positioning system which ensures all movements of the mirror at low frequency and selects the focus (Nasmyth A or B) using a hexapod concept. This subsystem is fixed rigidly to the mounting system and permits mirror displacements. The M4 control system (M4CS) ensures the connection between the telescope control/monitoring system and the M4 unit - positioning system (M4PS) and piezostack actuators in particular. This subsystem is composed of electronic boards, mechanical support fixed to the mounting structure and the thermal hardware. With piezostack actuators, most of the thermal load is minimized and dissipated in the electronic boards and not in the adaptive mirror. The mounting structure (M4MS) is the mechanical interface with the telescope (and the ARU in particular) and ensures the integrity and stability of M4 unit subsystems. M4 positioning system and mounting structure are subcontracted to Amos company. We will also report on the manufacturing of the demonstration prototype that will be tested in the next phase

    Demonstration prototype and breadboards of the piezo stack M4 adaptive unit of the E-ELT

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    International audienceIn order to mitigate the risks of development of the M4 adaptive mirror for the E-ELT, CILAS has proposed to build a demonstration prototype and breadboards dedicated to this project. The objectives of the demonstration prototype concern the manufacturing issues such as mass assembly, integration, control and polishing but also the check the global dynamical and thermal behaviour of the mirror. The local behaviour of the mirror (polishing quality, influence function, print through...) is studied through a breadboard that can be considered as a piece of the final mirror. We propose in this paper to present our breadboard strategy, to define and present our mock-up and to comment the main results and lessons learned

    Last progress concerning the design of the piezo stack M4 adaptive unit of the E-ELT

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    International audienceCILAS proposes a M4 adaptive mirror (M4AM) that corrects the atmospheric turbulence at high frequencies and residual tip-tilt and defocus due to telescope vibrations by using piezostack actuators. The design presents a matrix of 7217 actuators (triangular geometry, spacing equal to 29 mm) leading to a fitting error reaching the goal. The mirror is held by a positioning system which ensures all movements of the mirror at low frequency and selects the focus (Nasmyth A or B) using a hexapod concept. This subsystem is fixed rigidly to the mounting system and permits mirror displacements. The M4 control system (M4CS) ensures the connection between the telescope control/monitoring system and the M4 unit - positioning system (M4PS) and piezostack actuators of the M4AM in particular. This subsystem is composed of electronic boards, mechanical support fixed to the mounting structure and the thermal hardware. With piezostack actuators, most of the thermal load is minimized and dissipated in the electronic boards and not in the adaptive mirror. The mounting structure (M4MS) is the mechanical interface with the telescope (and the ARU in particular) and ensures the integrity and stability of M4 unit subsystems. M4 positioning system and mounting structure are subcontracted to AMOS company
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