Helium

Sales gas may typically contain only 0.05% helium and it is not economical to recover helium at this low concentration level. For comparison, the existing sources for commercial helium have approximately 0.3% to about 8% helium from natural gas reservoirs, with 0.3% often considered the economical limit for recovery. This paper addresses the technical and economic feasibility of producing Grade-A liquefied helium from sales gas containing low concentrations of helium using integrated NGL/NRU/HRU technologies vs the traditional stand-alone technologies.

Noble gases, inert elements having isotopes produced by the decay of long half-life radionuclides, offer a powerful approach for tracing fluid circulation and dating groundwa-ters.The (U + Th)-4He water ages-calculated from the accumulation rate in water of radio-genic 4He produced by decay of U and Th contained in the aquifer rocks-is frequently higher than the hydrological ages. This discrepancy is generally interpreted by two contrasting models: (i) heterogeneities of the aquifers, which allow water stagnation and accumulation of large amounts of radiogenic 4He, or (ii) addition of 4He produced in deeper regions of the continental crust. In this contribution, we propose that the apparent contrast between (U + Th)-4He ages and hydrological ages in the Paris Basin reflects the mixing of different types of water, having different residence times. We show, using the helium isotopic signatures of waters, that this mixing occurs between three aquifers, the Middle Jurassic, the Triassic and the Palaeozoic basement, which have contrasting helium contents and heterogeneous chemical compositions and permeabilities. The difference of radiogenic 4He/4~ ratios between the aquifers of Triassic and Middle Jurassic strongly suggests that a significant fraction of helium is produced in the aquifer rocks. This implies residence times for groundwaters circulating in the Middle Jurassic carbonate aquifer much longer than those obtained from hydrological studies. Independent fluid age estimates, based on the ground palaeotemperatures recorded in the same groundwaters by the atmosphere-derived noble gases, seem to confirm the presence of very old groundwaters in the Paris Basin.

This study is aimed at recognizing possible sources of dispersion of density measurements of welded ignimbritic rocks by helium pycnometer. The values of bulk density and solid fraction volume, useful for volcanological studies as well as for a complete definition of the mechanical properties of these rocks, commonly used for present or historical buildings, are often tricky to obtain, due to the presence of micropores and the high tor-tuosity of the porous network. Three samples representative of different lithofacies of Miocene ignimbrites from San Pietro Island (SW Sardinia, Italy), have been used here to tune up a density measurement method. Basing on a statistical study of the density data derived from different analytical strategies, we propose a specific procedure for determining to measure density of welded ignimbritic rocks. Several measurements (runs) are performed on the undisturbed and on powered specimens of the three samples, using two different methods of gas-purging of the pycnometer: flow and pulse purging modes, respectively. The main factors that can produce a source of accidental errors are: uncontrolled fluctuations in temperature of the instrument, pollution of the sample (e.g., moisture), intrinsic petrophysical characteristics (e.g., pore tortuosity) of ignimbritic rocks. Conversely, the main systematic errors introduced in the measurements revealed to be related to the selected time and mode of gas-purging of the instrument during the first steps of the analysis. Using an appropriate sequence of contiguous cycles, accuracy and precision of data can be optimized, thus excluding systematic errors. The results show that in the first cycle, regardless of the purge time (or pulses), the values of density and standard deviations are always higher compared to the second and the third cycles. Basing on the analysis of our data, we propose that the better procedure to obtain an accuracy data is using 10-run cycles and considering the average value of the last seven measures.

In these few pages through a number of essential intermediate steps, an opening has been made to one of the most pressing questions concerning the core of the quantum world that has remained unanswered for decades ... the enigma of the unseparable quarks.

If the presumptions made in this document, points in the right direction, it means that the fundamental strong force has been stripped of that haze of indefinability and at the same time QCD, gluons, the residual strong force … are on their way to the archaeological box of quantum science.

In helium saturated rat abdominal adipose tissue, helium bubbles were studied at 101.3 kPa during breathing of either heliox(80:20), 100% oxygen or air after decompression from an exposure to heliox at 405 kPa for one hour. While breathing heliox bubbles initially grew for 15-115 minutes then shrank slowly; three out of 10 bubbles disappeared in the observation period. During oxygen breathing all bubbles initially grew for 10-80 minutes then shrank until they disappeared from view; in the growing phase, oxygen caused faster growth than heliox breathing, but bubbles disappeared sooner with oxygen breathing than with heliox or air breathing. In the shrinking phase, shrinkage is faster with heliox and oxygen breathing than with air breathing. Air breathing caused consistent growth of all bubbles. With heliox and oxygen breathing, most animals survived during the observation period but with air breathing, most animals died of decompression sickness regardless of whether the surrounding ...

Heliox is a low density gas mixture of helium and oxygen commonly used in deep diving (> 6 ATM). This mixture has been also used for clinical purposes, particularly in the critical care setting. Due to of its physical proprieties, Heliox breathing reduces air flow resistances within the bronchial tree; in patients with obstructive lung diseases Heliox may also reduce the work of breathing and improve pulmonary gas exchange efficiency. Beneficial effects have been documented in severe asthma attacks and in patients with chronic obstructive pulmonary disease. A reduction in WOB during mechanical ventilation and an increase in exercise endurance capacity have also been described in COPD. Heliox has been also used in the treatment of upper airways obstruction, bronchiolitis and bronchopulmonary dysplasia. Despite the encouraging results, Heliox use in routine practice remains controversial because of technical implications and high costs.

Knowledge of the electronic structures of atomic and molecular systems deepens our understanding of the desired system. In particular, several information-theoretic quantities, such as Shannon entropy, have been applied to quantify the extent of electron delocalization for the ground state of various systems. To explore excited states, we calculated Shannon entropy and two of its one-parameter generalizations, Rényi entropy of order α and Tsallis entropy of order α, and Onicescu Information Energy of order α for four low-lying singly excited states (1s2s 1 S e , 1s2s 3 S e , 1s3s 1 S e , and 1s3s 3 S e states) of helium. This paper compares the behavior of these three quantities of order 0.5 to 9 for the ground and four excited states. We found that, generally, a higher excited state had a larger Rényi entropy, larger Tsallis entropy, and smaller Onicescu information energy. However, this trend was not definite and the singlet-triplet reversal occurred for Rényi entropy, Tsallis entropy and Onicescu information energy at a certain range of order α.

Several noble gases, although classified as inert substances, exert a tissue-protective effect in different experimental models when applied before organ ischaemia as an early or late preconditioning stimulus, after ischaemia as a post-conditioning stimulus or when given in combination before, during and/or after ischaemia. A wide range of organs can be protected by these inert substances, in particular cardiac and neuronal tissue. In this review we summarize the data on noble gas-induced cardioprotection, focusing on the underlying protective mechanisms. We will also look at translatability of experimental data to the clinical situation.

Purpose: To develop a dynamic magnetic resonance imaging (MRI) tagging technique using hyperpolarized helium-3 (HP He-3) to track lung motion. Methods and Materials: An accelerated non-Cartesian k-space trajectory was used to gain acquisition speed, at the cost of introducing image artifacts, providing a viable strategy for obtaining whole-lung coverage with adequate temporal resolution. Multiple-slice two-dimensional dynamic images of the lung

Experimental research in cardiac and neuronal tissue has shown that besides volatile anesthetics and xenon, the non-anesthetic noble gas helium also reduces ischemia–reperfu-sion damage. Even though the distinct mechanisms of heli-um-induced organ protection are not completely unraveled, several signaling pathways have been identified. Beside the protective effects on heart and brain that are mainly obtained by different pre- and postconditioning protocols, helium also exerts effects in the lungs, the immune system, and the blood vessels. Obviously, this noble gas is biochemically not inert and exerts biologic effects, although until today the question remains open on how these changes are mediated. Because of its favorable characteristics and the lack of hemodynamic side effects, helium is suitable for use also in critically ill patients.