Helium Research Articles

Exploring the Conformational Landscape of Poly(l-lysine) Dendrimers Using Ion Mobility Mass Spectrometry.

Ion mobility mass spectrometry (IM-MS) measures the mass, size, and shape of ions in the same experiment, and structural information is provided via collision cross-section (CCS) values. The majority of commercially available IM-MS instrumentation relies on the use of CCS calibrants, and here, we present data from a family of poly(l-lysine) dendrimers and explore their suitability for this purpose. In order to test these compounds, we employed three different IM-MS platforms (Agilent 6560 IM-QToF, Waters Synapt G2, and a home-built variable temperature drift tube IM-MS) and used them to investigate six different generations of dendrimers in two buffer gases (helium and nitrogen). Each molecule gives a highly discrete CCS distribution suggestive of single conformers for each m/z value. The DTCCSN2 values of this series of molecules (molecular weight: 330-16,214 Da) range from 182 to 2941 Å2, which spans the CCS range that would be found by many synthetic molecules including supramolecular compounds and many biopolymers. The CCS values for each charge state were highly reproducible in day-to-day analysis on each instrument, although we found small variations in the absolute CCS values between instruments. The rigidity of each dendrimer was probed using collisionally activated and high-temperature IM-MS experiments, where no evidence for a significant CCS change ensued. Taken together, this data indicates that these polymers are candidates for CCS calibration and could also help to reconcile differences found in CCS measurements on different instrument geometries.

Analyzing Richtmyer–Meshkov Phenomena Triggered by Forward-Triangular Light Gas Bubbles: A Numerical Perspective

In this paper, we present a numerical investigation into elucidating the complex dynamics of Richtmyer–Meshkov (RM) phenomena initiated by the interaction of shock waves with forward-triangular light gas bubbles. The triangular bubble is filled with neon, helium, or hydrogen gas, and is surrounded by nitrogen gas. Three different shock Mach numbers are considered: Ms=1.12,1.21, and 1.41. For the numerical simulations, a two-dimensional system of compressible Euler equations for two-component gas flows is solved by utilizing the high-fidelity explicit modal discontinuous Galerkin technique. For validation, the numerical results are compared with the existing experimental results and are found to be in good agreement. The numerical model explores the impact of the Atwood number on the underlying mechanisms of the shock-induced forward-triangle bubble, encompassing aspects such as flow evolution, wave characteristics, jet formation, generation of vorticity, interface features, and integral diagnostics. Furthermore, the impacts of shock strengths and positive Atwood numbers on the flow evolution are also analyzed. Insights gained from this numerical perspective enhance our understanding of RM phenomena triggered by forward-triangular light gas bubbles, with implications for diverse applications in engineering, astrophysics, and fusion research.

Simulation and Experimental Verification of Dispersion and Explosion of Hydrogen–Methane Mixture in a Domestic Kitchen

Hydrogen is a carbon-free energy source that can be obtained from various sources. The blending of hydrogen represents a transitional phase in the shift from natural gas systems to hydrogen-based systems. However, concerns about the safety implications of introducing hydrogen have led to extensive discussions. This paper utilizes Fluent 17.0 numerical simulation software to simulate the leakage of hydrogen-blended natural gas in a closed domestic kitchen and analyze the concentration distribution and its variation pattern after a leakage. An experimental platform is set up, and a mixture of nitrogen and helium gas is used as a substitute for hydrogen-blended natural gas for the simulations and experiments. The simulation results demonstrate that the leaked gas spreads and accumulates towards the top of the space, gradually filling the entire area as the leak persists. As the hydrogen content in the leaked gas increases, the dispersion capacity of the gas in the confined space also increases. Furthermore, as the flow rate of the leaked gas increases, the average concentration of the leaked gas rises, and the gas stratification in the confined kitchen diminishes. The concentration distribution observed in the experiments aligns with the simulation results. After establishing the feasibility conditions of the model, the dispersion of the hydrogen-blended natural gas in the kitchen is further simulated. The results suggest that blending hydrogen into the gas enhances the dispersion of the gas after a leak, leading to a wider distribution within the kitchen and an increased risk in the event of a leak. Additionally, this paper employs the CASD module of FLACS 11.0 software to construct a three-dimensional geometric model of the domestic kitchen for simulation studies on the explosion of hydrogen-blended natural gas in a confined space. By adjusting the hydrogen ratio in the combustible gases present in the space and examining the variations in hydrogen concentration and external conditions, such as opening or closing the door, the influence on parameters including the peak explosion pressure, explosion overpressure, explosion flame temperature, and explosion response time are examined. Furthermore, the extent of the explosion area is determined, and the effect of hydrogen on the blast is clarified.

Enhancement of signal intensity of elements in human blood serum using a metal mesh-enhanced CO2 laser-induced breakdown spectroscopy in ambient He gas

Accurate and reliable identification and analysis of the elemental composition of human blood serum is of utmost importance. The present investigation included the analysis of human blood serums for elemental composition using a metal mesh-supported CO2 laser-induced breakdown spectroscopy under a helium gas environment at atmospheric pressure. In this study, a pulsed transversely excited atmospheric CO2 laser with a wavelength of 10.64 µm and a pulse duration of 200 ns was applied to irradiate the human blood serum film placed on a copper metal to induce a luminous plasma. A significant increment of elemental signal intensity occurs by introducing a metal mesh covering the serum film. Qualitative and quantitative analyses have been conducted on the human blood serum's major, minor, and trace elements. The concentrations of elements in the human blood are estimated to be 9160 parts per million (ppm) for carbon (C), 174 ppm for calcium (Ca), 600 ppm for potassium (K), 1410 ppm for magnesium (Mg), 343 ppm for phosphorus (P), 2180 ppm for sodium (Na), and 48 ppm for iron (Fe). The results of the CO2 LIBS method demonstrate a high level of concurrence with the results obtained by the conventional XRF method.

The design and development of the cryogenic compressed gas refueling system

As a new economical, efficient and feasible high density hydrogen storage method, cryogenic compressed hydrogen has been widely explored by scholars in recent years. In this paper, a new cryogenic compressed hydrogen refueling system based on liquid nitrogen cooling is proposed on the basis of the existing high pressure hydrogenation station at normal temperature. The main operating modes of the system include precooling, refueling and standby mode. During the refueling process, it can generate cryogenic compressed hydrogen at 80K temperature and 35MPa pressure, with a mass flow rate of 1kg/min. Additionally, when the cryogenic compressed hydrogen tank requires refueling at high temperatures, the system can provide precooling to reduce hydrogen loss and increase the refueling speed. To validate the feasibility of key equipment and the proposed system, helium gas is used as the working medium for testing. The construction of the cold box, compressor, and cryogenic tank have been completed, and the system is expected to undergo commissioning in the near future.

Development of Brayton circulating cooling system

The Brayton Circulating Cooling System is a unique refrigeration system designed to demonstrate the basic technology needed to provide cold helium gas refrigeration at high pressures to an external superconducting magnet or any remote load for cool down purposes. The system is designed to provide cool down refrigeration from room temperature to target minimum temperatures of approximately 40 K. The system consists of an F-70H helium compressor with gas control manifold, interconnecting gas lines, cables, the Brayton refrigeration unit mounted in a Dewar assembly and control system. The helium compressor uses high purity helium gas for its refrigerant. Electricity, cooling water for the compressor and a source of pure helium (99.995%) for make-up gas are the only required utilities. The scope of the project, system design, target specifications and summary of test results will be discussed in this paper.

Cryogenic aspects of a 20 MW class low-temperature superconducting generator for the renewables industry

In this paper we give a progress update on the cryogenic design for cooling a 20 MW class, partially superconducting generator with stationary field coils for offshore wind renewables industry [1-2]. This is a continuation of an earlier program on a 10 MW system dating back ten years. Whereas this new power rating increase leads to a radial diameter expansion of the superconducting field coils from 4 to > 9.5 m, it maintains the axial length. We show the design based on this scaled up with enlarged diameter. The field coil size increase asks for higher cooling power that leads to a bigger cold box size to accommodate the cryocoolers. In the design, as many as 8 cryocoolers can be accessed and serviced from the nacelle that houses the main cryogenic components. A typical thermal load balance sheet with all components is given and compared against the available cryocooler cooling power at different operating conditions. Due to the cryocoolers’ local point of contact cooling within the nacelle, the temperature gradient of the thermal shield that fully encloses the cold mass with its embedded field coils needs to be balanced out to minimize the heat burden on the field coils. This requires additional analytical efforts and implementation of further design features. The extended nacelle houses the cold box with its cryogenic infrastructure. The interface for the envisaged cryogenic pushbutton closed-loop circulating system remains invisible, requires no handling of cryogenic liquids and is hermetically closed. The field coil diameter increase also leads to a greater initial helium gas storage volume. In addition, it requires higher initial room temperature fill pressure within the toroidal helium vapor storage tanks and in cooling tubes connecting to the cryocoolers. The toroidal helium gas tanks are thermally coupled with the thermal shield so that helium convection inside the storage tank can improve heat transfer and reduce the temperature gradient of the thermal shield. Besides those heat transfer challenges, additional mechanical strain within this large structure is exerted on the torque tubes during initial cooldown and when energizing field coils. Some of those design challenges are quite unexpected, leading to novel workarounds in order to maintain the chosen cooling strategy. Finally, we assess those design limitations in view of further cryogenic scalability with emphasis on manufacturability and assembly.

Thermal Modeling of CryoFILL liquefaction tests

Proposed NASA missions to Moon and Mars involve producing cryogenic propellant in-situ to reduce launch mass and requirements. One technique for liquefaction of the gases produced through electrochemical processes is to circulate cold gaseous neon or helium through broad area cooling tubes attached to the outside of the propellant tanks. To determine the performance of this liquefaction process tests were conducted at NASA Glenn Research Center in a 2.1 cubic meter tank with a broad area cooling network (CryoFILL). A thermal/fluid model of the tank and its cooling loop is developed in Thermal Desktop. Details of the model and the model predictions and comparison to some of the experimental data from the CryoFILL liquefaction tests are presented here.

Using mylar-insulated cryopumping panels to improve vacuum level during warm temperature testing at JSC’s large thermal vacuum facilities

Johnson Space Center’s Space Environment Simulation Lab (SESL) has both Chamber A, the world’s largest purpose-built thermal vacuum chamber capable of creating deep space conditions, and Chamber B, the largest human rated thermal vacuum chamber. A unique design feature of these chambers is the gaseous helium cryopumping panels within the liquid nitrogen shroud. This shroud is used to bring the chamber to cryogenic temperatures while the cryopumping panels trap gasses on its surface area to create a high vacuum environment of 5*10−6 Torr. In preparation for the James Webb Space Telescope (JWST) flight test, a series of functionals required the chamber to run at higher temperatures, and therefore did not need active cooling from the liquid nitrogen shroud. During testing, cryopumping panels were used to mitigate contamination during this main shroud warm-up. One of the cryopumping panels in Chamber A was covered with several layers of aluminized mylar to thermally protect the zone from the warmed shroud. This strategy was effective and became part of operations during JWST testing. Currently, Chamber B has requests for both commercial and NASA space suit tests at both high and low temperatures to validate thermal models. High temperature tests could benefit from reduced heater demand with an insulated shroud while still sustaining the high vacuum environment provided by the cryopumping panels. This paper will quantitatively define the thermal loads on the panels used in previous Chamber A warm up sequences. Additionally, this report will perform thermal analyses to assess the feasibility of adding layers of aluminized mylar to the cryopumping panels of Chamber B.

Development of an 18 kW@4.5 K & 4 kW@2 K Helium Refrigerator

An 18 kW@4.5 K & 4 kW@2 K helium refrigerator is being developed in China by the Technical Institute of Physics and Chemistry, CAS. This large-scale helium refrigerator provides different cooling capacity at the 50-75 K, 4.5-75 K and 2 K levels. This helium refrigerator works based on Claude cycle refrigeration process, which uses 5 sets of turbines (10 turbines totally) to bring the temperature down to 4.5 K. Four cold compressors are arranged in series to pump gaseous helium from atmospheric pressure to 0.03 bar in order to decrease the temperature of 2 K helium bath from 4.5 K down to 2 K. A set of subatmospheric pressure compressors is used to compress subatmospheric helium gas downstream from cold compressors to medium pressure 4.05 bar and is connected directly to high pressure compressors. This paper provides an overview on the process design, system design and preliminary component design results in the development of this 18 kW@4.5 K & 4 kW@2 K helium refrigerator.

High-Current Capability and Upgrades of the EBIS/T Charge-Breeding System in the Reaccelerator at the Facility for Rare-Isotope Beams

The Reaccelerator (ReA) of the Facility for Rare-Isotope Beams (FRIB) at Michigan State University uses a Beam Cooler/Buncher (BCB) and an Electron-Beam Ion Trap (EBIT) as a charge-breeding injector system. The rare isotopes produced by In-flight Separation are selected by the Advanced Rare Isotope Separator (ARIS) and stopped in a helium gas cell. Long-lived and stable-isotope beams can also be extracted from a Batch-Mode Ion Source (BMIS). The continuous beams transported at low energy to ReA are injected into the BCB. The pulsed beams are then injected into the EBIT, charge bred, ejected, and accelerated by ReA’s LINAC. The EBIT electron current (300 - 600 mA) is a factor that limits its capacity to ∼2×1010 elementary charges, which restricts the maximum EBIT-extracted rates to less than 2×1010 particles per second for light ions. An upgrade of the EBIT electron gun is expected to provide 2 A in current. In parallel, a High-Current Electron-Beam Ion Source (HCEBIS) is being commissioned. The HCEBIS can presently provide an electron current of 2 A. An upgrade will increase the current to 4 A. The implementation of these two upgrades is expected to allow for maximum rates to be ∼1011 pps, compatible with FRIB projected rates and user demands. We review the high-current capabilities and upgrades of ReA’s charge-breeding system.

Cooling method for the rotor of a superconducting motor

Electrification has been proposed as a route to decarbonizing air travel. Conventional electric motors are too heavy to achieve the power densities required for aviation so superconducting motors for aircraft are being developed. Superconductors however, work at cryogenic temperatures, which indispensably require a reliable and efficient cooling mechanism with a cryocooler. The Robinson Research Institute is developing a 3 MW superconducting motor using an HTS (High Temperature Superconductor) rotor operating at 50 K and MgB2 running at near 20 K for the stator. The motor is intended to run at a shaft speed of 4500-6000 rpm to directly drive a ducted fan. A key challenge is the removal of heat from a cryogenic spinning rotor to a stationary refrigerator so it can be rejected at ambient temperatures. Previous motors have utilized externally pumped or thermos-syphoned cryogens to cool the rotor, which require complex rotary seals. The aircraft application demands a compact and low weight solution. This paper presents a novel cooling design where a stationary cryocooler’s cold heat exchanger penetrates the rotor, and the relative motion of the two creates a pumping motion for cold helium gas to transfer heat from the rotor to the cryocooler. The sealing is low pressure and at ambient temperature and pressure with a temperature gradient in the helium adjacent to the cryocooler regenerator. Design and CFD modelling of the concept are presented showing the system can generate sufficient cold helium flow to transfer heat from the rotor to the cryocooler with a small temperature difference, resulting in a compact, efficient, and low-weight rotor cooling method.

Nitrogen precooling heat exchanger replacement and control system upgrade in superfluid cryoplant at CMTF

Liquid nitrogen precooling is used in most cryoplants to achieve cooldown to 80 K temperature range. In one such system at Fermilab’s CMTF superfluid cryoplant, where the helium supply directly exchanges heat with liquid nitrogen, freezing of nitrogen occurred inside the heat exchanger due to heat exchanger flow imbalance during a cryoplant trip. Trapped vapor pockets of nitrogen within the frozen heat exchanger channels were formed while warming up the heat exchanger, creating high localized pressure and subsequent damage/rupture of the heat exchanger. Replacement of the heat exchanger was done, and modifications were made in the system to rectify future occurrences. The control system was updated to bypass the heat exchanger entirely if the incoming helium stream temperature drops below 76 K. This was done by repurposing two control valves as heat exchanger bypass valves that were previously used for a redundant 80 K adsorber in the coldbox. Additional modifications were made to further prevent return of large amount of cold helium gas from cold end during abrupt cryoplant shutdown. This modification has ensured high reliability of heat exchanger with prevention of freezing of nitrogen which can damage the heat exchanger.

Stability of C59 Knockout Fragments from Femtoseconds to Infinity

We have studied the stability of C59 anions as a function of time, from their formation on femtosecond timescales to their stabilization on second timescales and beyond, using a combination of theory and experiments. The C59− fragments were produced in collisions between C60 fullerene anions and neutral helium gas at a velocity of 90 km s−1 (corresponding to a collision energy of 166 eV in the center-of-mass frame). The fragments were then stored in a cryogenic ion beam storage ring at the DESIREE facility, where they were followed for up to 1 minute. Classical molecular dynamics simulations were used to determine the reaction cross section and the excitation energy distributions of the products formed in these collisions. We find that about 15% of the C59− ions initially stored in the ring are intact after about 100 ms and that this population then remains intact indefinitely. This means that C60 fullerenes exposed to energetic atoms and ions, such as stellar winds and shock waves, will produce stable, highly reactive products, like C59, that are fed into interstellar chemical reaction networks.

Preliminary studies of the MINERVA cryogenic supply system

MYRRHA (Multi-purpose hYbrid Research Reactor for High-tech Applications) will be composed of a 600 MeV LINear ACcelerator (LINAC) with a large number of cryomodules and a 100 MW thermal power subcritical nuclear reactor cooled by lead-bismuth. The MINERVA MYRRHA Isotopes productioN coupling the linEar acceleRator to the Versatile proton target fAcility) project is the first phase of the MYRRHA project composed of a 100 MeV, 4 mA continuous-wave proton LINAC. The MINERVA LINAC takes advantage of 60 superconducting radiofrequency (RF) cavities cooled at 2 K by saturated superfluid helium (He II). The MINERVA cryoplant will supply the required cryogenic cooling power of the LINAC through cryogenic lines and cryogenic valve boxes. This paper describes the LINAC cryogenic system supply architecture, the different operating modes, the heat loads, the cryoplant main requirements and the strategy to comply with high reliability requirements. The MINERVA cryoplant shall provide helium flows at 40 K for the thermal shielding, at 5 K for the cooling of the RF couplers and at 2 K for the 60 superconducting cavities installed in 30 cryomodules. The total equivalent refrigeration power of the MINERVA cryoplant is about 3.5 kW at 4.5 K. The cryoplant is composed of a warm compression station including sub-atmospheric volumetric compressors, helium gas storages and a refrigeration cold box with cold centrifugal compressors.

Theoretical and experimental studies of gas preparation system for pressurization and reactive control system of launch vehicle

A new gas preparation system (GasPS-RCS) is proposed to solve two tasks: (A) to heat helium gas for tank pressurization; (B) to prepare gas for the Launch Vehicle (LV) Reactive Control System (RCS) at the LV orientation and stabilization sections of the LV on passive parts of the flight trajectory, to provide conditions for launching the Liquid Rocket Engine (LRE). The system includes a gas generator based on hydrogen peroxide, a separator for water separation, heat exchangers independent of the LRE, and gas-jet nozzles. The proposed new system allowed to reduce the length of pressurizing gas lines and reduce the increased helium gas consumption during the heat exchanger warm-up interval of the LRE during its launch. A special advantage of the proposed system is the possibility of ground testing of heat exchangers without an operating LRE. A mathematical model based on the first law of thermodynamics was used to perform a comparative analysis of GasPS-RCS with traditional pressurization and RCS systems. To validate the mathematical model, the experimental studies of helium pressurizing of a liquid nitrogen tank were conducted. The results show that the deviation of experimental and calculated values for pressure is 1.1% and for temperature up to 2%. According to the results of comparative analysis, the GasPS-RCS is 259 kg lighter for the first stage and 80 kg lighter for the second stage of the LV.

Development of high‐performance zinc stannate based multifunctional thermoplastic polyurethane nanocomposite films

AbstractA lot of demand exists for multifunctional TPU that can provide enhanced performance to address a variety of inflatable application needs. To develop multifunctional nanocomposite films for such uses, synthesized zinc stannate (ZnSnO3) nanoparticles are integrated for the first time in a thermoplastic polyurethane (TPU) matrix. ZnSnO3 was synthesized using hydrothermal method. The morphological analysis vividly displayed the nanocubic structures. As‐synthesized nano ZnSnO3 was added as a nanofiller at varied concentration from 2 to 10 wt% in TPU and nanocomposite films were prepared by solvent intercalation and casting method. These films were thoroughly examined for their multifunctional properties such as UV protection, helium gas barrier and infrared emissivity. Mean value of UV protection factor was improved by 75% at 10 wt% loading of ZnSnO3 whereas 23% improvement was observed in helium gas barrier. Moreover, a good correlation of experimental data with various theoretical models of gas permeability was obtained at lower volume fraction of ZnSnO3. IR emissivity value also showed improvement from 0.802 to 0.842. Thus, the developed TPU‐ZnSnO3 nanocomposite films exhibited a significant improvement in multiple functional properties with improved tensile strength at optimized loading of 6 wt% of ZnSnO3.Highlights UPF mean value of ZnSnO3 incorporated TPU film has been improved by 67%. Helium gas barrier has been improved by approximately 23% at 6 wt% loading. TPU film exhibited improved properties at optimized loading of 6 wt% of ZnSnO3. Nanocomposite TPU film can be employed in various weathering inflatables.

A Review on Natural Gas Origin and Composition

Natural gas is obtained naturally. It is a hydrocarbon mixture. Natural gas is clean fossil fuel. It is safe when transported. Methane is main constituent of natural gas. It may also contain higher order hydrocarbons, carbon dioxide, helium, hydrogen sulphide and noble gases. World is facing problem of environmental pollution. To combat menace of pollution alternative sources of energy should be used. Natural gas is the cleanest fuel. Demand of natural gas all over the world is increasing.

Using compressor inlet cooling process for a supercritical Brayton cycle with various supercritical gases to recover the waste heat from a biomass-driven open Brayton cycle

The heat loss of a biomass-driven open Brayton cycle (OBC) is recuperated in the current research with the help of a supercritical Brayton cycle (SBC) and a thermoelectric generator (TEG). The temperature of the gas entering the SBC compressor is reduced through an ammonia-water absorption chiller (ACH) for performance improvement. The SBC compressor inlet cooling is examined for four supercritical gases (Nitrogen, Carbon monoxide, Air, and Helium). Moreover, the best performance of the configuration with compressor inlet cooling is compared with that of the system without compressor inlet cooling. Although compressor inlet cooling brings about the most improvement in output electricity of the SBC in the case of helium, the exergy efficiency (ηex) of the system and unit cost of the product (UCP) do not improve as much as other gases due to the reduction in the output power of the TEG in the case of helium. In addition, helium conduces to the lowest ηex (38.29 %) and highest UCP (17.62 $GJ−1) among the gases. Hence, helium is unsuitable for the SBC in total waste heat recovery applications. On the contrary, air induces the best performance with an ηex of 39.6 % and a UCP of 17.3 $GJ−1. The enhancement in ηex is 6.66 % points when the waste heat of the OBC is fully recovered.

Characterization of polymetallic ore of zinc, copper and lead

The study aimed to characterize a sample of approximately 150 kg of polymetallic zinc, copper and lead ore from the Aripuanã region, Mato Grosso. Due to the strategic importance of these minerals in the Brazilian economy and the complexity of processing. To achieve the objective, techniques such as scanning electron microscopy (SEM) with energy dispersive X-ray analysis (EDS), X-ray diffraction (XRD) and inductively coupled plasma mass spectrometry (ICP) were used to identify the minerals and determine its chemical composition. Furthermore, the Bond Work Index (WI) test was performed to evaluate resistance to fragmentation, and helium gas pycnometry was used to analyze the specific mass. The results showed a specific mass of 2.89 g/cm³, a WI of 9.22 kWh/st and contents of 5.15% zinc, 0.15% copper and 1.30% lead. The presence of minerals carrying the study elements, such as galena, sphalerite and chalcopyrite, highlights the relevance of these findings for the mining and metallurgy industry, boosting sustainable development and consolidating Brazil's position as a producer of valuable mineral resources.