Search results for "fluids"
showing 10 items of 1936 documents
On the discreet spectrum of fractional quantum hydrogen atom in two dimensions
2019
We consider a fractional generalization of two-dimensional (2D) quantum-mechanical Kepler problem corresponding to 2D hydrogen atom. Our main finding is that the solution for discreet spectrum exists only for $\mu>1$ (more specifically $1 < \mu \leq 2$, where $\mu=2$ corresponds to "ordinary" 2D hydrogenic problem), where $\mu$ is the L\'evy index. We show also that in fractional 2D hydrogen atom, the orbital momentum degeneracy is lifted so that its energy starts to depend not only on principal quantum number $n$ but also on orbital $m$. To solve the spectral problem, we pass to the momentum representation, where we apply the variational method. This permits to obtain approximate analytica…
Characterizing and Quantifying Frustration in Quantum Many-Body Systems
2011
We present a general scheme for the study of frustration in quantum systems. We introduce a universal measure of frustration for arbitrary quantum systems and we relate it to a class of entanglement monotones via an exact inequality. If all the (pure) ground states of a given Hamiltonian saturate the inequality, then the system is said to be inequality saturating. We introduce sufficient conditions for a quantum spin system to be inequality saturating and confirm them with extensive numerical tests. These conditions provide a generalization to the quantum domain of the Toulouse criteria for classical frustration-free systems. The models satisfying these conditions can be reasonably identifi…
Optimal Heating of an Indoor Swimming Pool
2020
This work presents the derivation of a model for the heating process of the air of a glass dome, where an indoor swimming pool is located in the bottom of the dome. The problem can be reduced from a three dimensional to a two dimensional one. The main goal is the formulation of a proper optimization problem for computing the optimal heating of the air after a given time. For that, the model of the heating process as a partial differential equation is formulated as well as the optimization problem subject to the time-dependent partial differential equation. This yields the optimal heating of the air under the glass dome such that the desired temperature distribution is attained after a given…
[35] Determination of oxidized glutathione in blood: High-performance liquid chromatography
1994
Publisher Summary The measurement of glutathione status is important in determining oxidative stress in tissues and biological fluids. The ratio of reduced to oxidized glutathione (GSH/GSSG) is a good indicator of the oxidative stress that may occur under physiological and pathological conditions. Changes in GSSG levels have been considered as intracellular signals able to modulate enzyme activity. Thus, it is important to have accurate methods to determine GSSG in biological fluids and in cells. In many cases, it is possible to use tissues, such as liver, muscle, or brain to determine GSH/GSSG. However, especially in human studies, samples from these tissues are not readily available; the …
Association of military training with oxidative stress and overreaching.
2011
ABSTRACT: We hypothesized that increased oxidative stress and disrupted redox balance may be predisposing factors and markers for overreaching (OR). Purpose: The study's purpose was to examine whether oxidative stress markers and antioxidant status and physical fitness are related to OR during an 8-wk military basic training (BT) period. Methods: Oxidative stress and antioxidant status were evaluated in the beginning and after 4 and 7 wk of training in 35 males (age = 19.7 ± 0.3 yr) at rest and immediately after a 45-min submaximal exercise. Physical activity (PA) was monitored by an accelerometer throughout BT. Indicators of OR were also examined. Results: From baseline to week 4, increase…
Low-Intensity Neutron Emission from TiDx Samples Under Nonequilibrium Conditions
2001
Several experiments were performed that loaded titanium samples with deuterium from the gas phase, changed the temperature of the samples over a wide range, and monitored the neutron emission. Neutron emissions in very low intensity bursts, still significantly above the background, were recorded, revealing that low-energy nuclear reactions in condensed matter can be produced at a very low rate, which occasionally can be high enough to become detectable.
Novel method for determination of tritium depth profiles in metallic samples
2019
Tritium accumulation in fusion reactor materials is considered a serious radiological issue, therefore a lot of effort has been concentrated on the development of radiometric techniques. A novel method, based on gradual dissolution, for the determination of the total tritium content and its depth profiles in metallic samples is demonstrated. This method allows for the measurement of tritium in metallic samples after their exposure to a hydrogen and tritium mixture, tritium containing plasma or after irradiation with neutrons resulting in tritium formation. In this method, successive layers of metal are removed using an appropriate etching agent in the controlled regime and the amount of evo…
Myocardial Glutathione Alterations in Acute Coronary Occlusion in the Dog
1987
Glutathione (GSH) decreases in dog mycocardium upon acute coronary occlusion when compared with sham-operated dogs. Total glutathione content (GSHeq = GSH + ZGSSG) remains unchanged throughout the experiment (6 h after surgery) in both sham- and acute coronary occlusion-operated dogs. GSSG and GSH/GSSG ratio increases and decreases respectively in all animals but tends to reach the normal value after 6 h in sham-operated dogs. Both parameters (GSSG and GSH/GSSG ratio) remain altered in acute coronary occlusion-operated ones. This alteration of glutathione status in ischemic myocardium is discussed.
Milk as an Essential Source of Iodine in Latvian Population
2017
Abstract Milk and dairy products are studied as alternative iodine sources, because salt iodisation is controversial due to high salt consumption leading to cardiovascular diseases. However, the iodine concentration in milk markedly varies. This study evaluated the iodine concentration in cow’s milk available in the Latvian market. Iodine and fat concentration was analysed with a spectrophotometer “Varian Cary 50” based ISO 2446:2008 in 20 milk samples. Data from the Central Statistical Bureau and survey among pregnant women were used to analyse milk product consumption and its impact on iodine status. Average iodine concentration in milk samples was 457.6 (179.6) μg/L, winter samples had a…
Laboratory formation of a scaled protostellar jet by coaligned poloidal magnetic field
2014
International audience; Although bipolar jets are seen emerging from a wide variety of astrophysical systems, the issue of their formation and morphology beyond their launching is still under study. Our scaled laboratory experiments, representative of young stellar object outflows, reveal that stable and narrow collimation of the entire flow can result from the presence of a poloidal magnetic field whose strength is consistent with observations. The laboratory plasma becomes focused with an interior cavity. This gives rise to a standing conical shock from which the jet emerges. Following simulations of the process at the full astrophysical scale, we conclude that it can also explain recentl…