Analysis of the Downhole Measurement System’s Pressure and Temperature Measuring Channel Calibration Errors

Various measurements in wells are quite challenging due to the specific measurement conditions. There are some additional requirements for measurement systems, in particular, space restrictions. Therefore, measuring several parameters with a single sensor is rather important. The paper discusses a measurement system that allows measuring temperature and pressure with a single sensor – an SOS-based strain gauge pressure transducer with a bridge or half-bridge circuit. In this case, pressure and temperature measuring channels are calibrated individually, which creates another error component. The numerical simulation of calibration described herein shows that regardless of the sensor circuit, the voltage uncertainty band of both measuring channels is characterized by a reduced error of 0.03 % with a confidence probability P = 0.9.

Design of a Differential Safety Mechanism (DSM) Dedicated to the NSW Micromegas Wedges

The New Small Wheel Micromegas detector system for the Upgrade of ATLAS Muon Spectrometer is in the phase of integration and commissioning at the Laboratories BB5 and Building 191 at CERN respectively. In this framework, the produced modules are evaluated and tested at a Cosmic Ray Stand or at their final position on New Small Wheel. Providing gas mixture to the Micromegas Wedges, the static gauge pressure inside the detector’s layers must be kept below a nominal value around 3 mbar. Pressures above 10 mbar, due several reasons or gas line blocking, could cause serious damages in the detectors. In this work we describe the principle of operation and the design of a low cost intelligent unit, the “Differential Safety Mechanism”, dedicated to protect the Micromegas Wedges against unexpected slow or sudden increase of the static gauge pressure. The internal detailed structure, the simulation and the prototype tests of the DSM are presented analytically in this work.

Numerical study on the mechanism of drag reduction for interceptors on planning boats

The drag reduction effect of interceptors on planning boats has been widely proven, but the mechanism of the effect has been rarely studied in terms of drag components, especially for spray resistance. The resistance was caused by the high gauge pressure under the boats transformed from the dynamic pressure, and it is the largest drag component in the high-speed planning mode. In this study, numerical simulations of viscous flow fields around a planning boat with and without interceptors were conducted. A two degrees of freedom motion model was employed to simulate the trim and sinkage. The numerical results were validated against the experimental data. The flow details with and without the interceptor were visualized and compared to reveal the underlying physics. A thinner and longer waterline could be achieved by the interceptor, which made the boat push the water away more gradually, and hence, the wave-making resistance could be decreased. The improved waterline also reduced the component of the freestream normal to the hull surface and led to the less transformed dynamic pressure, resulting in the lowAer spray resistance. Furthermore, the suppression of the flow separation could also be benefited from the interceptor; the viscous pressure resistance was therefore decreased.

Corrosion Behaviour of Titanium Alloy and Carbon Steel in a High-Temperature, Single and Mixed-Phase, Simulated Geothermal Environment Containing H2S, CO2 and HCl

The corrosion behaviour of a new titanium-based alloy, with nickel, molybdenum and zirconium as the main alloying elements, was studied in a simulated geothermal environment at various phase conditions of a corrosive fluid. Corrosion testing of carbon steel was also conducted for comparison. Both materials were tested at an elevated temperature between 180 and 350 °C and at a 10 bar gauge pressure in H2O containing HCl, H2S, and CO2 gases with an acidic condensate of pH = 3. The study found that the titanium alloy demonstrated good corrosion resistance in a single- and multiphase geothermal environment. In the testing volume, where the boiling of testing fluid occurred, the carbon steel was prone to localized damage of oxide, sulphide and chloride corrosion products. In the superheated testing volume, a homogeneous oxide corrosion layer was observed on the carbon steel. In the testing volume where condensation of the testing fluid occurred, a sulphide layer with an oxide sublayer was formed on the carbon steel.

Formwork Pressure of a Heavyweight Self-Compacting Concrete Mix

High-fluidity and self-compacting concrete (SCC) mixes were developed using special aggregates for radiation-shielding concrete. The special aggregates comprised heavyweight and hydrous aggregates (crushed magnetite, crushed serpentine, and their mixtures), which were selected to provide an enhanced attenuation of gamma and neutron radiation, respectively. For the mixed concrete design with a bulk density of up to 3570 kg/m3, two cement types were used: Portland cement CEM I and slag cement CEM III/A. The basic properties of the fresh self-compacting concrete were evaluated and the lateral formwork pressure exerted by the freshly mixed self-compacting concrete was measured and analyzed. An original test setup was developed for the determination of the lateral pressure on the square column formwork with pressure measurements carried out using six strain gauge pressure transducers, which was adequate for heavyweight concrete mixture testing. Self-compacting concrete mixtures containing a magnetite aggregate or blends of serpentine and magnetite aggregates with a slump flow of at least 550 mm were developed. The lateral pressure on the formwork was directly proportional to the density of the self-compacting heavyweight concrete mixes. The maximum values of the lateral pressure recorded in the test at a casting speed of 1.5 m/h did not exceed 27 kPa and 55% of hydrostatic pressure. Concrete mixtures with basalt, magnetite, and magnetite/serpentine blended aggregates were found to develop sufficient shear strength for proper stability during casting.

Experimental study of a modified drafting system based on the ring spinning frame

A systematic study of a modified drafting system based on the ring spinning frame, which is called the SDS (soft drafting system), is reported in this article to raise yarn quality. Two parts of an experiment were conducted to investigate differences between the conventional and modified drafting systems by spinning three kinds of yarns (in part I) and the effects of process parameters (block gauge, pressure on the front rollers and break draft) on the SDS by using response surface methodology (RSM) to spin 18.2 tex cotton yarn (in part II). The results show that the SDS can significantly improve yarn evenness and reduce yarn imperfections of thick places by +35% and +50%, respectively, and neps by +140% per km. In addition, it is noted that the three parameters are all statistically significant for the SDS to spin yarns, while interactions between them are not. More importantly, RSM predicted a minimum CVm% of 13.95% under the optimum conditions of 1.75 mm, 190 N and 1.21 for the block gauge, pressure on the front rollers and break draft, respectively, which is very close to the conditions of the practical spinning test.

2D flow model for calculating effective area of piston-cylinder units

A 2D flow model is described for calculation of the effective area (<em>A</em>) of pressure-measuring piston-cylinder units (PCU) based on their dimensional properties. With the 2D model, the uncertainty contribution associated with PCU's axial non-symmetry can be eliminated and the uncertainty of <em>A</em> can be reduced. The 2D model is applied to several primary PCUs operated in absolute and gauge pressure modes with different pressure-transmitting media. The benefit of the 2D model in dependence on PCU's geometrical perfectness is discussed.