Gas Injection System Research Articles

Direct electron beam writing of silver using a β-diketonate precursor: first insights.

Direct electron beam writing is a powerful tool for fabricating complex nanostructures in a single step. The electron beam locally cleaves the molecules of an adsorbed gaseous precursor to form a deposit, similar to 3D printing but without the need for a resist or development step. Here, we employ for the first time a silver β-diketonate precursor for focused electron beam-induced deposition (FEBID). The used compound (hfac)AgPMe3 operates at an evaporation temperature of 70-80 °C and is compatible with commercially available gas injection systems used in any standard scanning electron microscope. Growth of smooth 3D geometries could be demonstrated for tightly focused electron beams, albeit with low silver content in the deposit volume. The electron beam-induced deposition proved sensitive to the irradiation conditions, leading to varying compositions of the deposit and internal inhomogeneities such as the formation of a layered structure consisting of a pure silver layer at the interface to the substrate covered by a deposit layer with low silver content. Imaging after the deposition process revealed morphological changes such as the growth of silver particles on the surface. While these effects complicate the application for 3D printing, the unique deposit structure with a thin, compact silver film beneath the deposit body is interesting from a fundamental point of view and may offer additional opportunities for applications.

Design, characterization, and modeling of the Charge eXchange Recombination Spectroscopy (CXRS) suite at the SMall Aspect Ratio Tokamak (SMART).

Ion temperature, rotation, and density are key parameters to evaluate the performance of present and future fusion reactors. These parameters are critical for understanding ion heat, momentum, and particle transport, making it mandatory to properly diagnose them. A common technique to measure these properties is charge exchange recombination spectroscopy (CXRS). For characterizing positive and negative triangularity plasmas at the small aspect ratio tokamak, a poloidal array of gas puff based CXRS diagnostics will be measuring the ion properties in different poloidal positions. In this work, the modeling of the expected signal and spatial coverage using the FIDASIM code is presented. Furthermore, the design and characterization of the low field side midplane CXRS diagnostic are described. Each diagnostic is composed of a gas injection system, an optical system that collects the light emitted by the plasma, and a spectrometer. These systems will provide ion temperature, rotation, and density with a radial resolution of 3.75mm and a temporal resolution of 2.2ms.

Review of: "focused ion beam nanolithography requires a gas injection system to produce a local deposition from a precursor material that is delivered in the form of gas, with precursor separation created by appropriate radiation in nanoelectrical devices."

Review of: "focused ion beam nanolithography requires a gas injection system to produce a local deposition from a precursor material that is delivered in the form of gas, with precursor separation created by appropriate radiation in nanoelectrical devices."

Integration of Scanning Electrochemical Microscopy and Scanning Electrochemical Cell Microscopy in a Bifunctional Nanopipette toward Simultaneous Mapping of Activity and Selectivity in Electrocatalysis.

Scanning electrochemical microscopy (SECM) and scanning electrochemical cell microscopy (SECCM) were integrated in a single bifunctional probe for simultaneous mapping of the oxygen reduction current and the oxidation current of the produced H2O2. The dual probe is fabricated from a double-barrel θ capillary, comprising one open barrel filled with the electrolyte and another filled with pyrolytic carbon. Pt is deposited with a gas injection system (GIS) at the end of the carbon barrel. The probe integrates the advantages of both SECM and SECCM by forming an electrochemical droplet cell that embeds the Pt working electrode of the carbon barrel directly into the electrolyte meniscus formed upon sample contact from the electrolyte barrel. The versatility of the dual probe is demonstrated by mapping the oxygen reduction reaction (ORR) current and the H2O2 oxidation current of a Pt microstrip on a gold substrate. This allows simultaneous localized electrochemical measurements, highlighting the potential of the dual probe for broader applications in characterizing the electrocatalytic properties of materials.

Migration and balance of 13C in the stellarator Wendelstein 7-X after 13CH[formula omitted] local injection into the island divertor

A 13C tracer experiment was carried out to investigate impurity transport and migration in the stellarator Wendelstein 7-X (W7-X). About 4.0 × 1022 molecules of 13C marked methane were injected through the divertor gas injection system during plasma operation. After the experiment, the divertor target elements were extracted to be analyzed by post-mortem methods. In particular, the results of the Nuclear Reaction Analysis are presented, and the 13C balance and predominating contributors to migration are discussed.A two-dimensional 13C deposition pattern on 12C graphite modules was obtained with over 6000 single measurements. The post-mortem analysis results extrapolations show a high local deposition of around 25% of the 13C within a 5 cm radius around the injection holes embedded in a graphite target module of one of the ten divertor units. Additionally, a striation is detected in the toroidal direction along the outer strike line and the net carbon deposition zone along the intersecting magnetic island containing about 23% of the 13C within the same divertor unit where injections were made. The residual 52% of 13C are globally migrated across the machine. In total, ∼ 90% of the injected 13C could be extrapolated by post-mortem analysis. Thus, the 13C balance is closed. The distribution indicates a non-negligible amount of global transport and the strong influence of the magnetic topology on migration. In contrast to the strike line pathway, the transport along the magnetic island only takes place counterclockwise in toroidal direction. These results are used to provide benchmark data for ERO2.0 impurity tracing simulations and to be a reference for impurity migration processes in a stellarator.

Design of SIL-2 interlock function for tokamak fusion reactor

The ITER Gas Injection System (GIS) Regulates fueling and impurity gases during plasma discharges within the tokamak vacuum vessel. To implement ITER investment protection, the GIS requires capable of interlock function to shielding the gases from ITER vacuum chamber when Disruption Mitigation System (DMS) is triggered or an abnormality is detected, in order to prevent further damage caused by gas fueling. This paper presents the preliminary design of the interlock system for the ITER GIS per ITER plant interlock system design rules and guidelines. The design adopts a redundant and fault-tolerant architecture with fail-safe programmable logic controllers to achieve the required ITERs target Interlock Integrity Level of SIL-2. The solutions here facilitate the integration with ITER instrumentation and control system, also establishing reference models for other large-scale control system platforms.

Performance enhancement of microwave discharge cathode by external gas injection system

The effect of external gas injection near the plume on the performance of a microwave discharge cathode is investigated. Experiments were conducted under two gas injection conditions: gas addition and gas distribution. Gas distribution tended to lead to better performance than gas addition. In the gas distribution experiments, the total gas consumption was kept constant, the internal gas flow rate was reduced, and external gas was supplied. The electron current increased from 0.26 to 0.49 A at 35 V when the microwave power was 15 W. When the sum of the internal and external gas flow rates was held constant, external gas injection lowered the neutralization costs and increased the gas utilization efficiency. The neutralization current was successfully increased by 48 % at 12 W of microwave power compared with 8 W of microwave power with the same level of naturalization cost and gas utilization efficiency. The electron temperature and plasma density in the plume, as measured using a Langmuir probe, suggested that an increase of ionization in the plume by the external gas injection enhanced the cathode's performance.

Magnetron sputtering thruster operated with a compact gas feeding system using double pulsed valves

A continuous injection of gaseous water propellant into a magnetron-type sputtering propulsion device is performed in a pseudo manner by using a combination of two high-speed solenoid-type pulsed valves and a low-pressure gas reservoir . The gas injection system provides a temporally averaged gas flow rate of about 5–10 sccm with adjustment of the repetition frequencies of the pulsed valves, while the previously used single valve system attached to a liquid water tank has caused excessive gas injection. A discharge is sustained by a high voltage dc power supply; the discharge current has pulsation synchronized with the pulsed valve repetition. A temporally averaged force induced by the magnetron sputtering thruster and exerted on a pendulum plate downstream of the thruster is measured; the results are in good agreement with the previously reported force measurement under precisely controlled gas flow rate using a commercial mass flow controller. Therefore, the precise control of the gaseous water propellant with the compact gas feeding system is achieved, while maintaining a similar thruster performance to that with the mass flow controller.

Commissioning and first collisions with the LHCb SMOG2 system

Owing to the injection of gas in the CERN LHC accelerator beampipe through the System for Measuring Overlap with Gas (SMOG), the LHCb experiment has been pioneering since 2015 fixed-target physics at the highest energy ever reached. Within the upgrade of the experiment, a confinement cell for the gas, SMOG2, and a new gas injection system were installed. This dedicated setup opens unique possibilities for extensive measurements for heavyion, hadron, spin and astroparticle physics. In this contribution, the SMOG2 system is presented, focussing on its validation and first outcome as obtained from the exploitation of the proton-gas data collected in 2022.

Design Considerations for a Transient CHI Gas Injection System for Pegasus-III

Design Considerations for a Transient CHI Gas Injection System for Pegasus-III

Computational Study on Air Film Approach in Reentry Blackout Mitigation

Communication blackouts during the atmospheric reentry phase are a significant challenge, as flight data are lost due to interruptions caused by plasma gas generated by aerodynamic heating. This study explores a novel mitigation method using an air film, a thin insulating coolant layer on the surface. The researchers successfully reduced the reentry blackout by employing a gas injection system. Through a coupled approach using computational fluid dynamics and a frequency-dependent finite-difference time-domain method, the plasma flow properties and electromagnetic propagation were analyzed around a test model in a wind tunnel in DLR (German Aerospace Center). The numerical results indicated that the injected nitrogen gas formed an insulating air film layer on the surface. The thin layer advected backward, maintaining a low temperature without ionization, and covered the object in the wake region. The electromagnetic waves propagated and reached a distant area because the electron density was low. It means that the air film layer acted as a propagation window for the telecommunication waves. Thus, communication blackouts will be avoidable because electromagnetic waves can transmit through the air-film layer. It concluded that the air film effect, developed as a thermal protection technique, is a novel mitigation scheme for reentry blackouts.

“Depo-all-around”: A novel FIB-based TEM specimen preparation technique for solid state battery composites and other loosely bound samples

Interfacial phenomena between active cathode materials and solid electrolytes play an important role in the function of solid-state batteries. (S)TEM imaging can give valuable insight into the atomic structure and composition at the various interfaces, yet the preparation of TEM specimen by FIB (focused ion beam) is challenging for loosely bound samples like composites, as they easily break apart during conventional preparation routines. We propose a novel preparation method that uses a frame made of deposition layers from the FIB's gas injection system to prevent the sample from breaking apart. This technique can of course be also applied to other loosely bound samples, not only those in the field of batteries.

NETmix technology as ozone gas injection system: Assessment of the gas-liquid mass transfer

This work proposes an innovative high-intensity mixer based on the NETmix technology to promote the contact between ozone (O3) gas and water. The NETmix consists of a network of unit cells comprising mixing cylindrical chambers interconnected by prismatic channels. Its exclusive geometry generates successive contacting and splitting of flows, boosting mass transfer rates and rapidly developing an O3-enriched liquid stream. The gas-liquid mass transfer performance of NETmix was evaluated by measuring the volumetric mass transfer coefficient (kLa), standard oxygen transfer rate, standard oxygen transfer efficiency, and energy expenditure parameters. A co-current continuous flow condition was used to introduce a gas stream (consisting of either O3/oxygen(O2) or synthetic air) and a liquid stream (water), whereby it was varied the direction of co-current fluid flow (downwards or upwards) and the injected gas (QG) and liquid (QL) flowrates. The downward flow of gas and liquid streams enhanced the mass transfer phenomenon by at least 43 %. Moreover, the kLa values increased with QL and QG, reaching 2.46 s−1 at a low specific power consumption (25 kW m−3). The NETmix showed kLa values at least one order of magnitude larger than conventional contactors, maintaining a high-energy utilization efficiency (up to 19.4 kgO3 kWh−1).

Simulation and Optimization of Surface Gas Injection Systems for Underground Gas Storage.

With the rapid development and popularization of sensing technology and information technology, the demand for intelligence in the oil and gas industry and gas storage has increased. The optimized operation of surface engineering is an important part of intelligence. To master the operation law of the surface engineering of gas storage, improve the production management level, and reduce the cost of gas injection, we investigated the simulation and optimization of a surface gas injection system for practical underground gas storage. We propose calculation formulas for gas injection well pressure separately according to the ideal gas equation of state, the van der Waals equation, and the R-K equation and verify them using actual data. By comparing the calculation error of the data and the complexities for both the equation and the calculation process, we finally choose the formula derived from the ideal gas equation of state as the constraint condition for our research. Moreover, we model the surface gas injection system by using the Aspen HYSYS simulation software. From the variation in the compressor power, we determine that the equalizing pressure injection pattern is the optimal injection pattern and the optimal number of injection wells is three. In addition, we examine the relationship between injection flow and well pressure with injection time under the optimal injection pattern. Finally, we obtain the functional formula of well pressure and injection flow with injection time. The results can provide not only a basis for the gas injection decision making of production systems but also a basic guarantee for the digital transformation and intelligent operation of enterprises.

Engineering design and analysis of first wall on the high-magnetic-field-side for HL-2M tokamak

The first wall is one of the key in-vessel components, which would be employed for protecting the vacuum vessel and other in-vessel components (e.g. diagnostic components, gas injection system, resonant magnetic perturbation coils). The first wall is facing the high temperature plasma, and the graphite is adopted as plasma facing material for HL-2M tokamak due to its many excellent properties including high thermal conductivity, good thermal shock, thermal fatigue resistance and good compatibility with plasma. The first wall on the high-magnetic-field-side is consisted of the graphite tile, the back plate, supports and the adjustment plate, and no active cooling structure is considered except for the residual neutral beam power region. All of the first wall parts are assembled with different bolts, and they are easy to install and maintain during their running life. All of the analysis results based on the finite element method show that the structural design of the first wall on the high-magnetic-field-side has good heat transfer performance, satisfying the thermal design requirements during the plasma operation stage (the average value of heat load in the residual neutral beam power 1.0 MW/m2, thermal load in other region 0.3 MW/m2, pulse time 5 s) for HL-2M device. The first wall can also withstand the impact of the electromagnetic load caused by 1.8 MA plasma disruption, including the major disruption and the vertical displacement events.

Developments at CERN-ISOLDE’s OFFLINE 2 mass separator facility for studies of molecular ion beams

ISOLDE’s Offline 2 laboratory has been upgraded to facilitate development for the production and study of molecular ion beams. New gas injection systems have been implemented for both molecular formation in the ion source and in the radio-frequency quadrupole ion trap used for beam preparation. MagneToF detectors and time-resolved single ion counting data acquisition have been implemented for low intensity beams and studies of laser-atom or laser-molecule interactions. We present a study of the formation and ionization of BaF+ using the upgraded facility.

Effect of Crude Oil and Nitrogen Gas Flow Rates on the Time Taken for Flow Initiation of Waxy Crude Oil

Transportation of waxy crude oil in a production pipeline often encountered flow assurance issues, such as wax deposition. In a case where pipeline shutdown is needed, wax deposit is likely to form within the pipelines, which leads to operational complexity during the restart phase. Commonly, crude oil restarts to flow after a significantly high restart pressure is pumped longer than is necessary. This is due to the physical hindrance caused by the solid wax, which requires additional pressure to disintegrate it before achieving a steady crude oil flow. This study aims to investigate the effect of crude oil and nitrogen gas flow rates on the time taken for crude oil flow initiation using a flow loop rig, which is connected to a nitrogen gas injection system. The nitrogen gas was injected into the test section pipeline at predetermined flow rates within specified periods. After 45 min of static cooling, the crude oil gear pump is switched on to build sufficient pressure to initiate the waxy crude oil flow in the pipeline. Additionally, a statistical analysis by the response surface methodology was also performed by Minitab® 19 software. Results show that the maximum reduction in flow initiation is 73.7% at 5 L/min of crude oil and 1 L/min of nitrogen gas. This study reveals that the presence of nitrogen gas improved the pipeline restart phase by minimizing both restart pressure and time taken for flow initiation.

Work Flow, Advisory System Optimizes Intelligent Production Network

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 205735, “A Digital Oil Field Comprehensive Study: Automated Intelligent Production Network Optimization,” by Aulia A. Naufal, SPE, and Sabrina Metra, Schlumberger. The paper has not been peer reviewed. _ Leveraging technologies from a flow-assurance simulator, a Python application programming interface (API) toolkit, open-source machine-learning (ML) packages in Python, and a commercial visualization dashboard, the complete paper proposes a series of work flows to simplify model deployment and set up an automatic advisory system to provide insight as a means of justifying day-to-day engineering decisions. The complete paper discusses this methodology and provides a case study of its implementation, although this synopsis concentrates on the former. Background The authors identify four steps necessary for a valid network model that can describe production-system fluid-flow behavior accurately and support day-to-day decision making. These four steps, detailed in the complete paper, include the following: - Well-model building and matching - Well-basis gas lift evaluation - Network modeling - Gas-lift-optimization scenarios Work Flow Objective The objectives of creating an automated, intelligent production-network-optimization work flow include the following: - Minimize risk for data-quality issues caused by human error - Quicken pre- and post-deployment stages of the work flow, thus saving time and resources - Increase the functionality of a digital-oilfield work flow, including adding a production-surveillance dashboard, extracting publicly available temperature data from a weather-service API, and adding an ML autocalibration work flow Theoretical Basis Multiphase Steady-State Flow Simulator. A commercial flow simulator is used to simulate multiphase flow simulation throughout the production system from the reservoir to the surface facilities to enable comprehensive production- (and injection-) system analysis. By the term “steady state,” the authors mean that the mass flow rate is conserved throughout the system, with no accumulation of mass in any system component. This simulator is used from design to the optimization period of the oil, gas, and water production and injection systems. It is most often used by reservoir, production, and facilities engineers to model well performance, design artificial-lift systems, model pipeline networks and facilities, analyze field-development plans, and optimize production. Network modeling is necessary if the interaction of different components (such as compressors, separators, and wells) producing into a common gathering system must be considered (Fig. 1); the wellhead pressure and the deliverability of any well are influenced by the backpressure imposed by the production system. Network modeling also allows engineers to determine the effects of adding new wells and compression, looping flowlines, and changing separation systems. To analyze all components, the network should be solved based on the boundary conditions set on each component. The network will be converged when the pressure balance and mass balance at each node are within the specified tolerance. Then, parameters along the flow path (profile) and at each node in the network will be output. The authors discuss simulation settings, a network optimizer, and a flow-simulation Python toolkit in the complete paper.

In Situ Sputtering From the Micromanipulator to Enable Cryogenic Preparation of Specimens for Atom Probe Tomography by Focused-Ion Beam.

Workflows have been developed in the past decade to enable atom probe tomography analysis at cryogenic temperatures. The inability to control the local deposition of the metallic precursor from the gas-injection system (GIS) at cryogenic temperatures makes the preparation of site-specific specimens by using lift-out extremely challenging in the focused-ion beam. Schreiber et al. exploited redeposition to weld the lifted-out sample to a support. Here, we build on their approach to attach the region-of-interest and additionally strengthen the interface with locally sputtered metal from the micromanipulator. Following standard focused-ion beam annular milling, we demonstrate atom probe analysis of Si in both laser pulsing and voltage mode, with comparable analytical performance as a presharpened microtip coupon. Our welding approach is versatile, as various metals could be used for sputtering, and allows similar flexibility as the GIS in principle.

Influences of key design parameters to operating performance of a compressed natural gas injection system using solenoid pressure regulator

A study is carried out to examine the effects of design parameters on operating performance of a compressed natural gas (CNG) injection system. This system consists of a solenoid-type injector, a solenoid pressure regulator, and a rail tube. To depict the operation of the injection system, mathematical models are built, including electrical and mechanical models of a solenoid pressure regulator and a solenoid injector. To control rail tube gas pressure, a control model is built using proportional integral derivative (PID) algorithm. The simulated gas pressure is compared with experimental result for validating the mathematical models. The influences of design parameters, including rail tube volume, stiffness of spring, and number of coil turns in the solenoid pressure regulator, on the operating performance of the CNG system are examined. The simulation results indicate that the stability of controlled gas pressure is increased when increasing the volume of the rail tube and spring stiffness. Besides, by decreasing the number of coil turns in the solenoid pressure regulator, the stability of controlled gas pressure and flow rate of the injection is increased.