Self-field effects upon the critical current density of flat superconducting strips

We develop a general theory to account self-consistently for self-field effects upon the average transport critical current density Jc of a flat type-II superconducting strip in the mixed state when the bulk pinning is characterized by a field-dependent depinning critical current density Jp(B), where B is the local magnetic flux density. We first consider the possibility of both bulk and edge-pinning contributions but conclude that bulk pinning dominates over geometrical edge-barrier effects in state-of-the-art YBCO films and prototype second-generation coated conductors. We apply our theory using the Kim model, JpK(B) = JpK(0)/(1+|B|/B0), as an example. We calculate Jc(Ba) as a function of a perpendicular applied magnetic induction Ba and show how Jc(Ba) is related to JpK(B). We find that Jc(Ba) is very nearly equal to JpK(Ba) when Ba > Ba*, where Ba* is the value of Ba that makes the net flux density zero at the strip's edge. However, Jc(Ba) is suppressed relative to JpK(Ba) at low fields when Ba < Ba*, with the largest suppression occurring when Ba*/B0 is of order unity or larger.Comment: 9 pages, 4 figures, minor revisions to add four reference

Esophageal acid stimulation alters insular cortex functional connectivity in gastroesophageal reflux disease

BACKGROUND: The insula plays a significant role in the interoceptive processing of visceral stimuli. We have previously shown that gastroesophageal reflux disease (GERD) patients have increased insular cortex activity during esophageal stimulation, suggesting a sensitized esophago-cortical neuraxis. However, information regarding the functional connectivity (FC) of the insula during visceral stimulation is lacking. The primary aim of this study was to investigate the FC of insular subregions during esophageal acid stimulation. METHODS: Functional imaging data were obtained from 12 GERD patients and 14 healthy subjects during four steady state conditions: (i) presence of transnasal esophageal catheter (pre-infusion); (ii) neutral solution; (iii) acid infusion; (iv) presence of transnasal esophageal catheter following infusions (post-infusion). The insula was parcellated into six regions of interest. FC maps between each insular ROI and interoceptive regions were created. Differences in FC between GERD patients and healthy subjects were determined across the 4 study conditions. KEY RESULTS: All GERD patients experienced heartburn during and after esophageal acidification. Significant differences between GERD patients and healthy subjects were seen in: (i) insula-thalamic FC (neutral solution infusion, acid infusion, post-infusion); (ii) insula-amygdala FC (acid infusion, post-infusion); (iii) insula-hippocampus and insula-cingulate FC (post-infusion). CONCLUSIONS & INFERENCES: Esophageal stimulation in GERD patients revealed significant insular cortex FC differences with regions involved in viscerosensation and interoception. The results of our study provide further evidence that the insula, located at the transition of afferent physiologic information to human feelings, is essential for both visceral homeostasis and the experience of heartburn in GERD patients

Magnetic-field dependence of the critical currents in a periodic coplanar array of narrow superconducting strip

We calculate the magnetic-field dependence of the critical current due to both geometrical edge barriers and bulk pinning in a periodic coplanar array of narrow superconducting strips. We find that in zero or low applied magnetic fields the critical current can be considerably enhanced by the edge barriers, but in modest applied magnetic fields the critical current reduces to that due to bulk pinning alone.Comment: 23 pages, 7 figure

Geometrical edge barriers and magnetization in superconducting strips with slits

We theoretically investigate the magnetic-field and current distributions for coplanar superconducting strips with slits in an applied magnetic field H_a. We consider ideal strips with no bulk pinning and calculate the hysteretic behavior of the magnetic moment m_y as a function of H_a due solely to geometrical edge barriers. We find that the m_y-H_a curves are strongly affected by the slits. In an ascending field, the m_y-H_a curves exhibit kink or peak structures, because the slits prevent penetration of magnetic flux. In a descending field, m_y becomes positive, because magnetic flux is trapped in the slits, in contrast to the behavior of a single strip without slits, for which m_y =0.Comment: 11 pages, 5 figures, revtex

Krylov Complexity in Lifshitz-type Scalar Field Theories

We investigate various aspects of the Lanczos coefficients in a family of free Lifshitz scalar theories, characterized by their integer dynamical exponent, at finite temperature. In this non-relativistic setup, we examine the effects of mass, finite ultraviolet cutoff, and finite lattice spacing on the behavior of the Lanczos coefficients. We also investigate the effect of the dynamical exponent on the asymptotic behavior of the Lanczos coefficients, which show a universal scaling behavior. We carefully examine how these results can affect different measures in Krylov space, including Krylov complexity and entropy. Remarkably, we find that our results are similar to those previously observed in the literature for relativistic theories.Comment: 26 pages, 12 figures; v2:minor improvements, matches published versio

Evaluation of ultrasound technology to break seed dormancy of common lambsquarters (Chenopodium album)

Although seed dormancy is advantageous for annual plants in the wild, unsynchronized germination in the laboratory leads to increased error in measurements. Therefore techniques to promote and synchronize germination are routinely used. Ultrasound is one of the newest methods for breaking dormancy in weed seeds. We have investigated whether ultrasonic waves can be used to break seed dormancy of common lambsquarters (Chenopodium album), a highly competitive annual weed that leads to significant reduction of yields of corn, soybeans, and sugar beets. Ultrasonic waves with frequency of 35kH were applied for 0 (control), 5, 10, 15 and 30 minutes using a completely randomized design. The results showed that the use of ultrasound waves generally enhanced the traits under investigation in the treated samples compared to the control sample. The maximum enhancement of germination percentage (180%), seedling dry weight (78%), and seedling vigor index I (271%) and II (392%) was seen in the common lambsquarters samples treated with ultrasound for 15 minutes and seedling length (40%) at 30 minutes compared to the control samples. Radical lengths were not statistically different from controls under any treatment and plumule length only increased marginally. These changes are reflected in seedling vigor index I and II measurements. For some of these traits, increasing the length of ultrasound treatment to 30 minutes had negative effects. These results demonstrate that ultrasound technology can be used as a quick, and efficient non-destructive method to break seed dormancy in common lambsquarters

Magnetic-field and current-density distributions in thin-film superconducting rings and disks

We show how to calculate the magnetic-field and sheet-current distributions for a thin-film superconducting annular ring (inner radius a, outer radius b, and thickness d<<a) when either the penetration depth obeys lambda < d/2 or, if lambda > d/2, the two-dimensional screening length obeys Lambda = 2 lambda^2/d << a for the following cases: (a) magnetic flux trapped in the hole in the absence of an applied magnetic field, (b) zero magnetic flux in the hole when the ring is subjected to an applied magnetic field, and (c) focusing of magnetic flux into the hole when a magnetic field is applied but no net current flows around the ring. We use a similar method to calculate the magnetic-field and sheet-current distributions and magnetization loops for a thin, bulk-pinning-free superconducting disk (radius b) containing a dome of magnetic flux of radius a when flux entry is impeded by a geometrical barrier.Comment: 10 pages, 13 figure

Human health risk assessment due to ambient PM10 and SO2 by an air quality modeling technique

Exposure to air pollutants may be an important environmental risk factor for human health. The main objective of this study was to assess the health impacts of exposure to particulate matter of aerodynamic diameter <= 10 mu g (PM10) and to sulfur dioxide (SO2) using the AirQ2.2.3 software developed by the WHO European Center for Environment and Health. Daily concentrations of PM10 and SO2 were used to assess the health effects. With regard to the mortality, the results showed that 3.9 (95 CI: 3.3-4.5) of total, 4.2 (95 CI: 2.7-9.05) of cardiovascular, and 6.2 (95 CI: 4.2-16.9) of respiratory mortality were related to PM10 concentrations above 10 mu g/m(3), respectively. In addition, 1.7 (95 CI: 1.3-2.06) of total, 3.4 (95 CI: 0.78-5.0) of cardiovascular, and 2 (95 CI: 2.5-5.7) of respiratory death were attributed to SO2 levels higher than 10 mu g/m(3), respectively. Given these findings, urgent policy decisions are needed to reduce the death caused by air pollution, and better quantification studies are recommended. (C) 2017 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved

Physical, chemical and biological quality assessment of aqueduct (Qanat) water for drinking, agriculture and irrigation of urban green spaces

BACKGROUND AND OBJECTIVES: The aqueduct is one of the most complex and amazing inventions of human history, created to meet the most vital needs of human society in arid and semiarid regions areas. If aqueducts are properly maintained, reconstructed, and restored, they can be valuable water supply system from ground water resources. The quality of the water in these sources will have a direct impact on the consumer of its consumption, so it seems necessary to check the water quality of these sources.METHODS: This study investigated the state of five aqueducts in Tehran using parameters such as calcium, magnesium, phosphate, sulfate, turbidity, total hardness, nitrate, alkalinity, electrical conductivity, Biochemical Oxygen Demand, Chemical Oxygen Demand, total coliform and fecal coliform. Then the obtained values were compared with the permissible limits of the World Health Organization and the national standard of Iran. The data was analyzed using SPSS26 software and a one-sample t-test.FINDINGS: The results of water quality during a one-year survey period showed that the parameters of alkalinity, electrical conductivity, total dissolved solids, sulfate, and nitrate were below the maximum desirable and permissible standards of the national standard of Iran and the World Health Organization, and therefore will not create any restrictions for drinking and agricultural use. Total hardness, phosphate, turbidity, calcium, magnesium, and chlorine have discrepancies with the national standards of Iran and the World Health Organization and these components must be adjusted for use. According to the one-sample t-test, there was a significant difference between the average and the permissible values of all parameters except magnesium at the 95% confidence level. All aqueducts except the America aqueduct had levels of fecal coliform that were higher than the maximum allowed by the environmental standards therefore, before using the aqueduct, it must be purified to control the environmental standards.. However, the total coliform, Biochemical Oxygen Demand, Chemical Oxygen Demand levels were not a problem. In addition, the water quality of these sources was placed in a group (C3S1) based on the Wilcox diagram.CONCLUSION: The physical and chemical analysis of the studied aqueduct water showed that the water quality is suitable for the irrigation of green spaces and salt-resistant plants. The biological characteristics of the studied aqueduct water also revealed that these sources were polluted by domestic and industrial effluents. This issue will only grow worse with time, as the amount of rainwater decreases and the amount of pollution in the underground water sources increases

Hysteretic characteristics of a double stripline in the critical state

Analytical investigations of the critical state are carried out for a superconducting stripline consisting of two individual coplanar strips with an arbitrary distance between them. Two different cases are considered: a stripline with transport current and strips exposed to a perpendicular magnetic field. In the second case, the obtained solutions correspond to "fieldlike" (for unclosed strips) and "currentlike" (for a long rectangular superconducting loop) states in an isolated strip to which both a transport current and a magnetic field are applied with constant ratio.Comment: 8 pages, 6 figures. accepted by SS