Stabilization of the m=1m=1 mode in a long-thin mirror trap with high-beta anisotropic plasmas

Stability of a ``rigid'' ballooning mode $m = 1$ is studied in application to a mirror axisymmetric trap designed to confine anisotropic plasma with a large beta ($\beta$, the ratio of plasma pressure to magnetic field pressure). It was found that for effective stabilization by lateral perfectly conducting wall, the beta parameter must exceed some critical value $\beta_{\text{crit}}$. The dependence of $\beta_{\text{crit}}$ on the plasma anisotropy, mirror ratio and width of vacuum gap between plasma and the wall was studied. Unlike the works of other authors focused on the plasma model with a sharp boundary, we calculated the boundaries of the stability zone for a number of diffuse radial pressure profiles and several axial magnetic field profiles. With a combination of a conducting lateral wall and conducting end plates imitating the attachment of end MHD stabilizers to the central cell of an open trap, there are two critical values of beta and two stability zones, $\beta \beta_{\text{crit}2}$, which can merge, making the entire range of allowable beta values $0<\beta<1$ stable.Comment: 26 pages, 12 figures, 3 tables. arXiv admin note: text overlap with arXiv:2203.0837

Neutron data field in a fission reactor core with fusion neutron source at pulse-periodic operation

Results are presented on the distinctive features of the energy release dynamics in the hybrid thorium reactor operating in combination with the neutron source based on the extended magnetic mirror trap. In the reactor core configuration under study, the high-temperature plasma column is formed in a pulse-periodic mode. At a certain duty cycle (pulse ratio) of the plasma column formation, it can be expected that the fission "wave" will be formed diverging from the axial region of the system and propagating in the radial direction in the fuel assembly (blanket). Under such conditions, in order to correct the resulting offset of the energy release distribution, it is necessary to optimize the fuel composition of the assembly in order to obtain the most appropriate radial distributions of physical parameters. The studies are carried out on the basis of the full-scale model of the reactor core, in which the axial region is modified: the extended magnetic mirror trap operating as a source of fusion neutrons is installed in the reactor core axial region

Wall stabilization of the rigid ballooning m=1m=1 mode in a long-thin mirror trap

The prospect of stabilization of the $m=1$ ``rigid'' ballooning mode in an open axially symmetric long-thin trap with the help of a conducting lateral wall surrounding a column of isotropic plasma is studied. It is found that for effective wall stabilization, the beta parameter must exceed $70\%$. The dependence of the critical beta on the mirror ratio, the radial pressure profile, and the axial profile of the vacuum magnet has been studied. It is shown that when a conductive lateral wall is combined with conductive end plates simulating attachment of the end MHD stabilizers to the central cell of an open trap, there are two critical beta values and two stability zones that can merge, making stable the entire range of allowable beta values $0<\beta<1$.Comment: 17 pages, 7 figure

A Simple Algorithm for Semiquantitative Analysis of Scored Histology Data in the R Environment, on the Example of Murine Non-Alcoholic Steatohepatitis Pharmacotherapy

Despite the high medical and socioeconomic burden of non-alcoholic fatty liver disease (NAFLD), treatments that could effectively reduce histological liver damage in this condition are lacking. As providing only qualitative data is a major limitation of most histological scoring systems, we aimed to develop a simple and straightforward algorithm for semiquantitative analysis of scored histology data using the extended Fisher’s exact test in the R environment. As an illustrative example, we used the effects of L-ornithine L-aspartate (LOLA) and empagliflozin (EMPA) in a 3-month chemical/dietary murine model of NAFLD. 100 C57Bl/6 mice were randomized into 4 groups: Intact (n = 10), Control (NAFLD; n = 30), LOLA (NAFLD + 1.5 g·kg−1 b.w./d LOLA orally; n = 30), and EMPA (NAFLD + 10 mg·kg−1 b.w./d EMPA orally; n = 30). LOLA reduced hepatitis activity (p p p p < 0.01). The statistical approach we suggest can be used as a simple complementary tool for exploratory analysis of scored histology data

A Simple Algorithm for Semiquantitative Analysis of Scored Histology Data in the R Environment, on the Example of Murine Non-Alcoholic Steatohepatitis Pharmacotherapy

Despite the high medical and socioeconomic burden of non-alcoholic fatty liver disease (NAFLD), treatments that could effectively reduce histological liver damage in this condition are lacking. As providing only qualitative data is a major limitation of most histological scoring systems, we aimed to develop a simple and straightforward algorithm for semiquantitative analysis of scored histology data using the extended Fisher&rsquo;s exact test in the R environment. As an illustrative example, we used the effects of L-ornithine L-aspartate (LOLA) and empagliflozin (EMPA) in a 3-month chemical/dietary murine model of NAFLD. 100 C57Bl/6 mice were randomized into 4 groups: Intact (n = 10), Control (NAFLD; n = 30), LOLA (NAFLD + 1.5 g&middot;kg&minus;1 b.w./d LOLA orally; n = 30), and EMPA (NAFLD + 10 mg&middot;kg&minus;1 b.w./d EMPA orally; n = 30). LOLA reduced hepatitis activity (p &lt; 0.05), cholestasis, necrosis, and fibrosis severity (p &lt; 0.01), and EMPA prevented necrosis (p &lt; 0.05) and reduced fibrosis severity (p &lt; 0.01). The statistical approach we suggest can be used as a simple complementary tool for exploratory analysis of scored histology data

Fusion-fission hybrid reactor facility: neutronic research

The authors investigate the neutronic characteristics of the operating mode of a hybrid nuclear-thermonuclear reactor. The facility under study consists of a modified core of a high-temperature gas-cooled thorium reactor and an extended plasma neutron source penetrating the near-axial region of the core. The proposed facility has a generated power that is convenient for the regional level (60–100 MW), acceptable geometric dimensions and a low level of radioactive waste. The paper demonstrates optimization neutronic studies, the purpose of which is to level the resulting offsets of the radial energy release field, which are formed within the fuel part of the blanket during long-term operation and due to the pulsed operation of the plasma D-T neutron source. The calculations were performed using both previously developed models and the SERPENT 2.1.31 precision program code based on the Monte Carlo method. In the simulation, we used pointwise evaluated nuclear data converted from the ENDF-B/VII.1 library, as well as additional data for neutron scattering in graphite from ENDF-B/VII.0, based on the S (α, β) formalism

Fusion-fission hybrid reactor facility: neutronic research

The authors investigate the neutronic characteristics of the operating mode of a hybrid nuclear-thermonuclear reactor. The facility under study consists of a modified core of a high-temperature gas-cooled thorium reactor and an extended plasma neutron source penetrating the near-axial region of the core. The proposed facility has a generated power that is convenient for the regional level (60–100 MW), acceptable geometric dimensions and a low level of radioactive waste. The paper demonstrates optimization neutronic studies, the purpose of which is to level the resulting offsets of the radial energy release field, which are formed within the fuel part of the blanket during long-term operation and due to the pulsed operation of the plasma D-T neutron source. The calculations were performed using both previously developed models and the SERPENT 2.1.31 precision program code based on the Monte Carlo method. In the simulation, we used pointwise evaluated nuclear data converted from the ENDF-B/VII.1 library, as well as additional data for neutron scattering in graphite from ENDF-B/VII.0, based on the S (α, β) formalism

Fusion-fission hybrid reactor facility: power profiling

The current state of research in the field of nuclear and thermonuclear power aimed at creating power generation plants makes it possible to predict the further development of modern power industry in the direction hybrid reactor power plants. Such hybrid systems include a tokamak with reactor technologies, worked out in detail in Russia, and systems with an additional source of neutrons. Power generation plants using tokamaks and accelerators with the required level of proton energy will be of exceptionally large size and power, which will postpone their construction on an industrial scale to the distant future. The ongoing research is aimed at the development of small generation and has the prospect of entering the field of energy use in a shorter period. The hybrid reactor facility under study consists of an axisymmetric assembly of fuel blocks of a high-temperature gas-cooled reactor and a linear plasma source of additional neutrons. The paper demonstrates the results of optimization plasma-physical, thermophysical and gas-dynamic studies, the purpose of which is to level the distortions of the power density field, which are formed in the volume of the multiplicating part of the facility due to the pulsed operation of the plasma source of D-T-neutrons. The studies on increasing the “brightness” of the source and modeling its operating modes were carried out using the DOL and PRIZMA programs. The thermophysical optimization and gas-dynamic calculations were performed using the verified SERPENT and FloEFD software codes. The calculations were made on a high-performance cluster of the Tomsk Polytechnic University

Changes in Brain Electrical Activity after Transient Middle Cerebral Artery Occlusion in Rats

Objectives. Ischemic stroke is a leading cause of death and disability worldwide. To search for new therapeutic and pharmacotherapeutic strategies, numerous models of this disease have been proposed, the most popular being transient middle cerebral artery occlusion. Behavioral and sensorimotor testing, biochemical, and histological methods are traditionally used in conjunction with this model to assess the effectiveness of potential treatment options. Despite its wide overall popularity, electroencephalography/electrocorticography is quite rarely used in such studies. Materials and methods. In the present work, we explored the changes in brain electrical activity at days 3 and 7 after 30- and 45-min of transient middle cerebral artery occlusion in rats. Results. Cerebral ischemia altered the amplitude and spectral electrocorticogram characteristics, and led to a reorganization of inter- and intrahemispheric functional connections. Ischemia duration affected the severity as well as the nature of the observed changes. Conclusions. The dynamics of changes in brain electrical activity may indicate a spontaneous partial recovery of impaired cerebral functions at post-surgery day 7. Our results suggest that electrocorticography can be used successfully to assess the functional status of the brain following ischemic stroke in rats as well as to investigate the dynamics of functional recovery