The Normal Zone Propagation in ATLAS B00 Model Coil

The B00 model coil has been successfully tested in the ATLAS Magnet Test Facility at CERN. The coil consists of two double pancakes wound with aluminum stabilized cables of the barrel- and end-cap toroids conductors for the ATLAS detector. The magnet current is applied up to 24 kA and quenches are induced by firing point heaters. The normal zone velocity is measured over a wide range of currents by using pickup coils, voltage taps and superconducting quench detectors. The signals coming from various sensors are presented and analyzed. The results extracted from the various detection methods are in good agreement. It is found that the characteristic velocities vary from 5 to 20 m/s at 15 and 24 kA respectively. In addition, the minimum quench energies at different applied magnet currents are presented

Integrated live imaging and molecular profiling of embryoid bodies reveals a synchronized progression of early differentiation.

Embryonic stem cells can spontaneously differentiate into cell types of all germ layers within embryoid bodies (EBs) in a highly variable manner. Whether there exists an intrinsic differentiation program common to all EBs is unknown. Here, we present a novel combination of high-throughput live two-photon imaging and gene expression profiling to study early differentiation dynamics spontaneously occurring within developing EBs. Onset timing of Brachyury-GFP was highly variable across EBs, while the spatial patterns as well as the dynamics of mesendodermal progression following onset were remarkably similar. We therefore defined a \u27developmental clock\u27 using the Brachyury-GFP signal onset timing. Mapping snapshot gene expression measurements to this clock revealed their temporal trends, indicating that loss of pluripotency, formation of primitive streak and mesodermal lineage progression are synchronized in EBs. Exogenous activation of Wnt or BMP signaling accelerated the intrinsic clock. CHIR down-regulated Wnt3, allowing insights into dependency mechanisms between canonical Wnt signaling and multiple genes. Our findings reveal a developmental clock characteristic of an early differentiation program common to all EBs, further establishing them as an in vitro developmental model

20.5 kA current leads for ATLAS Barrel Toroid superconducting magnets

Three pairs of 20.5 kA current leads for the ATLAS Toroid Magnets have been designed, manufactured and tested at Kurchatov Institute. The current leads have a high mechanical reliability and the vacuum tightness under 30 bars of internal pressure. The insulation between the current carrying parts and the mounting flange, the hydraulic connections and the temperature gauges withstand the overvoltage of at least 2 kV. The current leads are fully equipped with diagnostics needed for safety and control. The current leads were tested up to 24 kA. According to CERN's specification they were also tested in the absence of any cooling at very slow current discharge rate (5 A/s) from 20.5 kA to zero without any excessive overheating. Nowadays the current leads are successfully used at the ATLAS Magnet Test Facility at CERN. (6 refs)

ATLAS B0 toroid model coil test at CERN

The ATLAS superconducting magnet system consists of a Barrel Toroid, two End-Cap Toroids and a Central Solenoid. The Barrel Toroid, with overall dimensions of 20-m diameter by 26-m length, is made of eight individual coils symmetrically assembled around the central axis with a warm structure. The system is presently under construction in industry. In order to verify the construction concepts a model coil B0, a 9-m short version of a single Barrel Toroid coil, was built. Since April 2001, an extensive test program is underway at CERN to characterize the mechanical, thermal, electrical and magnetic properties of the coil. The magnet successfully achieved the 20-kA nominal operating current in July 2001. The test program and the main results are reported. (9 refs)

Biofilter aquaponic system for nutrients removal from fresh market wastewater

Aquaponics is a significant wastewater treatment system which refers to the combination of conventional aquaculture (raising aquatic organism) with hydroponics (cultivating plants in water) in a symbiotic environment. This system has a high ability in removing nutrients compared to conventional methods because it is a natural and environmentally friendly system (aquaponics). The current chapter aimed to review the possible application of aquaponics system to treat fresh market wastewater with the intention to highlight the mechanism of phytoremediation occurs in aquaponic system. The literature revealed that aquaponic system was able to remove nutrients in terms of nitrogen and phosphorus

Reactive Magnetron Sputtering of ZrO2/Al2O3 Coatings: Alumina Content and Structure Stability

Ternary zirconia-alumina coatings with different compositional ratios, ranging from pure zirconia to 50% alumina content, were deposited by reactive sputtering from two targets, Zr and Al, in argon-oxygen mixtures. The coating composition was controlled by the Zr/Al target power ratio provided by two pulsed-DC power supplies. The coatings were ~1 µm thick and they were deposited on floating potential substrates at a temperature of 650±3K. XRD indicated that the pure zirconia coatings possessed a monoclinic structure with a grain size of 35-40 nm. Adding alumina to the zirconia coating stabilized the cubic zirconia phase and decreased the grain size to 10-15 nm. The alumina phase in the coatings remained amorphous. The hardness of the nanocomposite structure increased from 11.6±0.5 GPa to 16.1±0.5 GPa for an alumina content of 17%. At higher alumina concentrations, the zirconia phase became amorphous and the hardness decreased to 10-11 GPa. Structure stability of the zirconia-alumina coatings was studied by measuring the coating structure and hardness after annealing at temperatures up to 1173 K. Pure zirconia (m-ZrO2) coatings had low structure stability; the hardness reached a maximum value of 18±1 GPa after annealing at a temperature of 773-873K; however, at higher annealing temperatures the hardness decreased, reaching a minimum value of 12.3±0.6 GPa after annealing at 1173K. The hardness of the nanocomposite ZrO2/Al2O3 coating with various compositions increased with annealing temperature. The hardness of a coating with an alumina content of 17% reached a high value of 19.2±0.5 GPa after annealing at 1073-1173 K. Measurements of post annealing XRD analyses indicated that the stabilization of the coating structure with c-ZrO2/a-Al2O3 phases is the reason for the higher structure stability. From the analyses of phase stability and hardness before and after annealing, we conclude that adding alumina to the zirconia phase promotes the formation of nanocomposite c-ZrO2/a-Al2O3 coatings with a markedly higher stability than single-phase m-ZrO2. Highlights: 1. ZrO2/Al2O3 nanocomposite coatings were deposited by co-sputtering from Zr and Al targets. 2. Adding alumina to the zirconia coating stabilized the cubic zirconia phase. 3. ZrO2-17% Al2O3 coatings had a grain size of 10-15 nm and a hardness of 16.1±0.5 GPa. 4. ZrO2/Al2O3 coatings maintained a high hardness after annealing at 1173K with a high value of 19 GPa for alumina content of 17%. 5. The ZrO2/Al2O3 nanocomposite coatings were crack-free after annealing at 1173K

Thermal Stability of Filtered Vacuum Arc Deposited Er2O3 Coatings

Erbium oxide (Er2O3) coatings were deposited using filtered vacuum arc deposition (FVAD) and their structure and thermal stability were studied as a function of fabrication parameters. The coatings were deposited on silicon wafer and tantalum substrates with an arc current of 50 A and a deposition rate of 1.6 ± 0.4 nm/s. The arc was sustained on truncated cone Er cathodes. The influence of oxygen pressure (P= 0.40-0.93 Pa), bias voltage (Vb= -20, -40 or grounded) and substrate temperature (room temperature (RT) or 673K) on film properties was studied before and after post deposition annealing (1273K for 1 hour, at P~ 1.33 Pa). The coatings were characterized using X-ray diffraction (XRD), optical microscopy, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and Knoop Hardness. Optical microscope images indicated that the coatings had very low macroparticle concentration on their surface. The macroparticle diameters were less than 2.5 μm. The coatings were composed of only Er2O3 without any metallic phase under all deposition parameters tested. The coatings deposited on RT substrates were XRD amorphous and had a featureless cross-section microstructure. However, the coatings deposited on 673K heated substrates had a C-Er2O3 structure with (222) preferred orientation and weak columnar microstructure. The coating hardness varied with deposition pressure and substrate bias, and reached a maximum value of 10 GPa at P = 0.4 Pa and Vb = -40 V. The post-deposition annealing caused crystallization, and the coatings hardness dropped to 4 GPa with thermal treatment. However, after post-deposition annealing, no peeling or cracking appeared at the coating surface or the interface with the substrate