Process Identification through Test on Cryogenic System

UNICOS (UNified Industrial Control System) is the CERN object-based control standard for the cryogenics of the LHC and its experiments. It includes a variety of embedded functions, dedicated to the specific cryogenic processes. To enlarge the capabilities of the standard it is proposed to integrate the parametrical identification step in the control system of large scale cryogenic plants. Different methods of parametrical identification have been tested and the results were combined to obtain a better model. The main objective of the work is to find a compromise between an easy-to-use solution and a good level of process identification model. The study focuses on identification protocol for large delayed system, the measurement consistency and correlation between different inputs and outputs. Furthermore the paper describes in details, the results and the tests carried out on parametrical identification investigations with large scale systems

Advanced Control Facility for the CERN-UNICOS Framework

CERN, during last decade, has extensively applied the CERN/UNICOS framework to large scale cryoplant control system. An increase of interested to advanced control techniques and innovative simulation environment applied to cryogenic processes has also occur. Since new control algorithm development into UNICOS framework requires significant time, a control testing platform which can be externally connected can improve and simplify the procedure of testing advanced controllers implementation. In this context, the present paper describes the development of a control testing tool at CERN, which allows rapid control strategies implementation through the Matlab/Simulink® environment, coupled with the large scale cryogenics UNICOS control system or with the CERN PROCOS simulation environment. The time delays which are inherently introduced by network links and communication protocols are analyzed and experimentally identified. Security and reliability issues are also discussed

Helium Cryoplant Off-line Commissioning and Operator Training: Two Applications of the PROCOS Simulation System at CERN

The off-line commissioning step, through reliable simulation of physical models, aims to correct and validate control systems before their implementation into real equipments. It prepares and minimizes plant commissioning phase and at the same time validates the efficiency of the new process control logic. This paper describes how different CERN/UNICOS cryogenic control systems have been pre-commissioned off-line, using the CERN cryogenic simulation environment PROCOS. Some examples are reported. Additionally the presented simulation environment will be used for operator training. The second part of the paper will presents the simulation platform and the first feedback from the operation crew

Application of Object-Based Industrial Controls for Cryogenics

The first application of the CERN Unified Industrial Control system (UNICOS) has been developed for the 1.8 K refrigerator at point 1.8 in mid-2001. This paper presents the engineering methods used for application development, in order to reach the objectives of maintainability and reusability, in the context of a development done by an external consortium of engineering firms. It will also review the lessons learned during this first development and the improvements planned for the next applications

Hyaluronic acid modulates growth, morphology and cytoskeleton in embryonic chick skin fibroblasts

The action that hyaluronic acid (HA) exerts on cell proliferation was investigated in embryonic chick skin fibroblasts at different ages (7-14 days) and in different cell-cycle stages evaluated by flow cytometry (cells maintained with and without serum). Proliferation was estimated by 3H- thymidine incorporation and cell counting. The results demonstrated hyaluronic acid inhibits cell multiplication in all different environmental conditions examined. The inhibitory effect of HA is more evident in 14-day than 7-day old fibroblasts. The ability of HA to modulate 3H-thymidine incorporation did not involve a change in the time required for cells entering the S phase of the replicating cycle, but is due to a smaller number of cells entering in this phase. As the relationships between components of the extracellular matrix (ECM) and the cytoskeleton are known, parallel studies were carried out on some cytoskeleton proteins. Furthermore, by modifying the capacity of cells to adhere to the substrate, HA induced alterations in cell shape and in cytoskeleton components involved in these processes. We may hypothesize that HA, binding specific membrane receptors, affects cell adhesion and morphology inducing less receptivity of fibroblasts to mitogenic stimuli by transmembrane interactions with cytoskeleton

Cryogenics for the CERN Solar Axion Telescope (CAST) using a LHC Dipole Prototype Magnet

The axion, an as yet hypothetical particle predicted from the solution of the strong CP problem, constitutes a prime candidate for the galactic dark matter and also arises in supersymmetry and superstring theories. If existing, axions should be copiously produced in stellar interiors and there are theoretical expectations for a low-energy axion emission spectrum peaked around a mean energy of ~ 4.4 keV. To provide the experimental proof, a solar axion telescope is at present installed at CERN, which is expected to be in total 10-12 times more efficient than the present largest set-up in operation at the University of Tokyo. The telescope will use a decommissioned 10-m long LHC superconducting dipole prototype magnet, providing a magnetic field of 9 T in operation, to catalyse the solar axion to photon conversion, which then can be detected by low-background x-ray detectors. The paper describes the external and proximity cryogenic systems and their integration into the overall telescope assembly

Phenytoin and gingival mucosa: A molecular investigation.

Several distinct classes of drugs, such as anticonvulsants, immunosuppressants, and calcium channel blockers, caused gingival overgrowth. One of the main drugs associated with the gingival overgrowth is the anti-epileptic such as phenytoin, which affects gingival tissues by altering extracellular matrix metabolism. In our study, we evaluate the effect of phenytoin, a drug whose active substance is phenytoin, on gingival fibroblasts of healthy volunteers. Gene expression of 29 genes was investigated in gingival fibroblasts' cell culture treated with phenytoin compared with untreated cells. Among the studied genes, only 13 genes (CXCL5, CXCL10, CCR1, CCR3, CCR5, CCR6, IL-1A, IL-1B, IL-5, IL-7, IL-6R, BMP-2, and TNFSF-10) were statistically significant. All but one gene resulted downregulated after 24\u2009h of treatment with phenytoin. BPM2 was the only, although weakly, up-expressed gene. Probably, we have not highlighted overexpression of the other inflammatory molecules because the study was performed on healthy people. Many studies show that phenytoin induces the overexpression of these cytokines but, probably, in our study, the drug does not have the same effect because we used gingival fibroblasts of healthy people

Cryogenic Characteristics of the ATLAS Barrel Toroid Superconducting Magnet

ATLAS, one of the experiments of the LHC accelerator under commissioning at CERN, is equipped with a large superconducting magnet the Barrel Toroid (BT) that has been tested at nominal current (20500 A). The BT is composed of eight race-track superconducting coils (each one weights about 45 tons) forming the biggest air core toroidal magnet ever built. By means of a large throughput centrifugal pump, a forced flow (about 10 liter/second at 4.5 K) provides the indirect cooling of the coils in parallel. The paper describes the results of the measurements carried out on the complete cryogenic system assembled in the ATLAS cavern situated 100 m below the ground level. The measurements include, among other ones, the static heat loads, i.e., with no or constant current in the magnet, and the dynamic ones, since additional heat losses are produced, during the current ramp-up or slow dump, by eddy currents induced on the coil casing

First Cool-down and Test at 4.5 K of the ATLAS Superconducting Barrel Toroid Assembled in the LHC Experimental Cavern

The large ATLAS superconducting magnets system consists of the Barrel, two End-Caps Toroids and the Central Solenoid. The eight separate coils making the Barrel Toroid (BT) have been individually tested with success in a dedicated surface test facility in 2004 and 2005 and afterwards assembled in the underground cavern of the ATLAS experiment. In order to fulfil all the cryogenic scenarios foreseen for these magnets with a cold mass of 370 tons, two separate helium refrigerators and a complex helium distribution system have been used. This paper describes the results of the first cool-down, steady-state operation at 4.5 K and quench recovery of the BT in its final configuration

The Control System for the Cryogenics in the LHC Tunnel [First Experience and Improvements]

The Large Hadron Collider (LHC) was commissioned at CERN and started operation with beams in 2008. Several months of operation in nominal cryogenic conditions have triggered an optimisation of the process functional analysis. This lead to a few revisions of the control logic, which were realised on-the-fly. During the 2008-09 shut-down, and in order to enhance the safety, availability and operability of the LHC cryogenics, a major rebuild of the logic and several hardware modifications were implemented. The databases, containing instruments and controls in-formation, are being rationalized; the automatic tool, that extracts data for the control software, is being simplified. This paper describes the main improvements and sug-gests perspectives of further developments