Electron microscopic observations on the demanian system of female <i>Metoncholaimus denticaudatus</i> Schuurmans Stekhoven and Adam, 1931 (Nematoda)

Electron microscopic observations on the demanian system of female Metoncholaimus denticaudatus Schuurmans Stekhoven and Adam, 1931 from the Sluice Dock of Ostend lead to following conclusions: 1) there is no ductus uterinus; 2) the system is not a seminal receptacle; 3) it should be interpreted as an elaborate cascade system of glands, the secretion of which serves some important purpose related to reproduction

Experimental Tailer like Thermal Lag Engine to obtain pressure and volume diagrams//Motor de Lag Térmico experimental tipo Tailer para obtener diagramas de presión y volumen

AbstractThe Thermal Lag Engine (TLE) patented by Peter Tailer’s is briefly introduced. The discussion about the thermodynamic working principle of this external combustion machine is presented. For this work the claims in literature have been studied by the authors to design and develop an experimental installation with the objective of measuring for the first time the pressure-volume (pV) relationship of a TLE asdescribed by Tailer and West. The pV diagrams are presented here and support previous theoretical claims about the TLE. Their triangular form shows the effects described by West in the expansion and compression processes caused by the variation of the cold heat transfer area. Also the relationshipbetween the heat transfer capacity of the engine and its working frequency becomes apparent from the measurements, indicating that larger heater areas and limited cold heat transfer characteristics allow more work production per cycle at higher operating frequencies.Key words: thermal lag engine, pressure-volume diagrams, external combustion engines._______________________________________________________________________________ResumenSe introduce brevemente el Motor de Lag Térmico (MLT) patentado por Peter Tailer y se esboza el debate científico sobre la termodinámica de esta máquina de combustión externa. A partir del estudio de los distintos puntos de vista los autores de este trabajo desarrollaron una instalación experimental con elobjetivo de medir por primera vez la relación presión-volumen (pV) de un MLT como el descrito por Tailer y West. Los diagramas pV son presentados y apoyan los planteamientos teóricos previos sobre los MLT.Su forma triangular muestra los efectos descritos por West sobre los procesos de compresión y expansión debido a la exposición variable del área fría de intercambio de calor. Las mediciones pV muestran la relación que existe entre la capacidad de intercambio de calor del motor y su frecuencia de operación.Estas indican que más áreas de transferencia de calor en el lado de la fuente y una transferencia limitada hacia el sumidero aumentan la producción de trabajo a mayores frecuencias de operación.Palabras claves: motor de Lag térmico, diagramas de presión y volumen, motor de combustión externa.</p

New Method for Magnet Protection Systems Based on a Direct Current Derivative Sensor

A new method of the quench detection systems (QDS) designed for the LHC 600 A corrector magnet circuits and 6 kA individual powered quadrupole (IPQ) magnet circuits is presented. In order to improve the dependability of QDS, a direct measurement of the current derivative is proposed. The quench detection scheme for the 600 A corrector magnet circuits uses the current derivative numerically evaluated from a direct current measurement. In order to make the calculation stable, the current derivative is heavily filtered, thus introducing a significant phase shift, which restricts the operational range of circuit parameters such as the acceleration. For the 6-kA IPQ magnet circuits the main quench detection is based on a classical bridge configuration. The introduction of an additional detection channel for the direct measurement of the current derivative helps to overcome the lack of sensitivity to fully aperture symmetric quenches of the bridge configuration. Transformer-based current derivative sensors are currently under development, using cut cores for easy prototyping, performance control, and installation. Prototypes for the ±600 A current range and ramp rates between 0.1 and 5 A/s were built using different core materials (electrical steel and nanocrystalline cores) and pickup coils with 10 000 and 20 000 windings. In order to characterize the prototypes, the performance was defined in terms of mean sensitivity of the sensor response in [V/A/s] and the performance quality factor (PQF), defined as a percentage of nonlinearity of the response. An optimization procedure was implemented for finding the best configuration of the sensors, i.e., the air gap in the cut core in order to maximize the mean sensitivity and to minimize the PQF. The tests were carried out at different working points (current ranges and ramp rates) showing promising results (PQF <0.5% with a sensitivity of 5.5 mV/A/s)

Powering Tests and Magnet Training

In this paper the powering tests and magnet training during the hardware commissioning campaigns of Run 2 are discussed, and the implications of running at 7 TeV from a magnet training and reliability perspective are given. During Run 2, the efficiency of powering tests has steadily increased due to enhanced control software, more automatic analysis, and more experienced CERN personnel. The MP3 Intervention Matrix, used for documenting requalification procedures after interventions, is presented. Given that the main dipole circuits are considered the main bottleneck for reaching 7 TeV operation from a magnet training perspective, training of these circuits is discussed in detail with regards to training efficiency and electrical integrity. The training campaign of December 2018 comprised training of the main dipole circuit in sector 12, all main quadrupole circuits, the individually powered dipoles and quadrupoles, and the inner triplets of points 1 and 5. Due to time constraints, the training targets were only partially reached. In general the observed training behavior was encouraging, although training on the main dipole circuit in sector 12 was slower than expected. Also considering that all dipoles have previously reached a quench current of at least 12 kA before installation into the LHC, no showstopper was identified for reaching 7 TeV operation. With regards to reliability of magnet operation at 7 TeV, no problems are expected in terms of flattop quenches, but the sensitivity to UFO-induced quenches is expected to increase significantly

A New Cryogenic Test Facility for Large and Heavy Superconducting Magnets

CERN has recently designed and constructed a new cryogenic facility for testing large and heavy superconducting magnets at liquid helium temperatures. The facility, erected in a large assembly hall with cranes capable of up to 100 t, provides a cooling capacity of 1.2 kW at 4.5 K equivalent, 15-kW LN$_2$ cooling and warming capabilities for up to three magnets in parallel. The facility provides the required technical infrastructure for continuous and reliable operation. Test capabilities comprise electrical, cryogenics, vacuum and mechanical verification, and validation at ambient and liquid helium temperatures. A comprehensive survey and magnetic measurement system, comprising a hall-probe mapper, a rotating-coil magnetometer, a stretched wire, a translating fluxmeter, and a laser tracker, allows the detailed measurement of the magnetic field strength and quality on a large volume. The magnetic axes of the quadrupoles can be established within $\pm 0.2$ mm at $1 \sigma$ accuracy. The facility has been equipped with power supplies, three converters of $\pm 500$ A/120 V, and six converters of $\pm 600$ A/40 V, as well as the required energy extraction, quench protection, data acquisition, and interlocks for the testing of superconducting magnets for the FAIR project, currently under construction at the GSI Research Center, in Darmstadt, Germany. The versatile design of the facility, its layout, and testing capabilities complements CERN's other test infrastructures for large superconducting magnets. We report on the design, construction, and commissioning of the facility as well as the expected capabilities and performances for future tests of large and heavy superconducting magnets