Double discharge feasibility summary report

Acceleration of rocket propellant by double electric discharge

Assessment of Laws of the Wall During Flame–Wall Interaction of Premixed Flames Within Turbulent Boundary Layers

\ua9 The Author(s) 2024. The validity of the usual laws of the wall for Favre mean values of the streamwise velocity component and temperature for non-reacting flows has been assessed for turbulent premixed flame-wall interaction using Direct Numerical Simulation (DNS) data. Two different DNS databases corresponding to friction velocity-based Reynolds number of 110 and 180 representing unsteady head-on quenching of statistically planar flames within turbulent boundary layers have been considered. The usual log-law based expressions for the Favre mean values of the streamwise velocity and temperature for the inertial layer have been found to be inadequate at capturing the corresponding variations obtained from DNS data. The underlying assumptions of constant shear stress and the equilibrium of production and dissipation of turbulent kinetic energy underpinning the derivation of the usual log-law for the mean streamwise velocity have been found to be rendered invalid within the usual inertial layer during flame-wall interaction for both cases considered here. The heat flux does not remain constant within the usual inertial layer, and the turbulent flux of temperature exhibits counter-gradient transport within the so-called inertial layer for the cases considered in this work. These render the assumptions behind the derivation of the usual log-law for temperature to be invalid for application to turbulent flame-wall interaction. It has been found that previously proposed empirical modifications to the existing laws of the wall, which account for density and kinematic viscosity variations with temperature, do not significantly improve the agreement with the corresponding DNS data in the inertial layer and the inaccurate approximations for the kinematic viscosity compensated wall normal distance and the density compensated streamwise velocity component contribute to this disagreement. The DNS data has been utilised here to propose new expressions for the kinematic viscosity compensated wall normal distance and the density compensated streamwise velocity component, which upon using in the empirically modified law of wall expressions have been demonstrated to provide reasonable agreement with DNS data

Landau damping of dust acoustic solitary waves in nonthermal plasmas

Dust acoustic (DA) solitary and shock structures have been investigated under the influence of Landau damping in a dusty plasma containing two temperature nonthermal ions. Motivated by the observations of Geotail spacecraft that reported two-temperature ion population in the Earth's magnetosphere, we have investigated the effect of resonant wave-particle interactions on DA nonlinear structures. The KdV equation with an additional Landau damping term is derived and its analytical solution is presented. The solution has the form of a soliton whose amplitude decreases with time. Further, we have illustrated the influence of Landau damping and nonthermality of the ions on DA shock structures by a numerical solution of the Landau damping modified KdV equation. The study of the time evolution of shock waves suggests that an initial shock-like pulse forms an oscillatory shock at later times due to the balance of nonlinearity, dispersion and disspation due to Landau damping. The findings of the present investigation may be useful in understanding the properties of nonlinear structures in the presence of Landau damping in dusty plasmas containing two temperature ions obeying nonthermal distribution such as in the Earth's magnetotail

Addition of adenosine to hyperbaric bupivacaine in spinal anaesthesia does not prolong postoperative analgesia in vaginal hysterectomy

Background: Systemic administration of adenosine produces anti-nociception. Although literature supports intrathecal adenosine for neuropathic pain, its efficacy in postoperative pain remains unproven. There has been no study on the efficacy of adenosine on postoperative pain when administered with hyperbaric bupivacaine. The aim of our present study was to evaluate the efficacy of two different doses of intrathecal adenosine as an adjunct to 0.5% hyperbaric bupivacaine in patients undergoing vaginal hysterectomy under spinal anaesthesia. Method: Seventy-five women, aged 40-60 years and scheduled for vaginal hysterectomy under spinal anaesthesia, were included. Patients were allocated to three groups of 25 patients each to receive 500 μg adenosine (group I), 1000 μg adenosine (group II) and normal saline (group III) with 2.6 ml of 0.5% hyperbaric bupivacaine. Postoperative analgesia was provided with patient-controlled fentanyl. Time of administration of rescue analgesia and total dose of fentanyl were recorded. The times to full recovery of sensory and motor block were noted. Results: There were no differences in time to rescue analgesia and postoperative fentanyl consumption over 24 hours among the groups. There was no significant difference in onset of sensory and motor block or regression of sensory block, although statistically significant difference was noted in the time taken for regression of motor block. Conclusion: Intrathecal adenosine does not affect the postoperative analgesic requirement when administered with hyperbaric bupivacaine.Keywords: spinal anaesthesia, intrathecal adenosine, vaginal hysterectomy,postoperative analgesia, patient-controlled analgesi

Neutrino-driven instability of ion acoustic waves in an ultra-relativistic degenerate plasma

The coupling between ion-acoustic waves (IAWs) and a neutrino beam undergoing flavor oscillations in a dense, relativistically degenerate plasma is analyzed. The neutrino-driven streaming instability of the IAWs is investigated with relevance to plasma conditions at the last stage of stellar evolution in a massive supernova progenitor. The influence of neutrino beam parameters such as the energy of the incident neutrino beam and eigen-frequency of the neutrino flavor oscillations on the instability growth rate is obtained numerically. It is observed that the neutrino flavor oscillations significantly affect the neutrino-driven instability of the IAWs. Our results also indicate that the time period for the onset of the streaming neutrino-driven instability is shorter than the typical time period of a core-collapse supernova explosion. The findings of this investigation may shed new light on the understanding of underlying physical mechanism responsible for the core-collapse supernova

COVID-19 in Africa:Contextualizing impacts, responses, and prospects

It has become a truism that COVID-19 has impacted all countries and all people around the world, but in different ways. Yet this contextual diversity in the pandemic’s impacts, the responses by governments and other actors, and the prospects for recovery are only beginning to be understood. This is especially so for Africa, where, on the whole, the pandemic had a late start compared to other regions, but where the complex interactions among the disease, local health systems, and preexisting vulnerabilities linked to poverty, inequality, and fragile governance make such understanding particularly important. “Africa could become the next epicenter of the COVID-19 pandemic,” though thankfully the rate of infections has slowed in most parts of the continent in August and September. Yet the risk of a second wave of infections remains high, and in any case, the effects of the global recession and of governments’ lockdown regulations are layered upon a context of widespread poverty and constrained states, resulting in severe humanitarian, economic, and social impacts, with long-term implications for sustainable development on the continent. Setbacks to Africa’s sustainable development agenda have global implications, and this is true for the pandemic also. As argued by the United Nations Secretary General, “Only victory in Africa can end the pandemic everywhere

Obstetric anal sphincter injury: a systematic review of information available on the internet.

OBJECTIVE: There is no systematic evaluation of online health information pertaining to obstetric anal sphincter injury. Therefore, we evaluated the accuracy, credibility, reliability, and readability of online information concerning obstetric anal sphincter injury. MATERIALS AND METHODS: Multiple search engines were searched. The first 30 webpages were identified for each keyword and considered eligible if they provided information regarding obstetric anal sphincter injury. Eligible webpages were assessed by two independent researchers for accuracy (prioritised criteria based upon the RCOG Third and Fourth Degree Tear guideline); credibility; reliability; and readability. RESULTS: Fifty-eight webpages were included. Seventeen webpages (30%) had obtained Health On the Net certification, or Information Standard approval and performed better than those without such approvals (p = 0.039). The best overall performing website was http://www.pat.nhs.uk (score of 146.7). A single webpage (1%) fulfilled the entire criteria for accuracy with a score of 18: www.tamesidehospital.nhs.uk . Twenty-nine webpages (50%) were assessed as credible (scores ≥7). A single webpage achieved a maximum credibility score of 10: www.meht.nhs.uk . Over a third (21 out of 58) were rated as poor or very poor. The highest scoring webpage was http://www.royalsurrey.nhs.uk (score 62). No webpage met the recommended Flesch Reading Ease Score above 70. The intra-class coefficient between researchers was 0.98 (95% CI 0.96-0.99) and 0.94 (95% CI 0.89-0.96) for accuracy and reliability assessments. CONCLUSION: Online information concerning obstetric anal sphincter injury often uses language that is inappropriate for a lay audience and lacks sufficient accuracy, credibility, and reliability

Rectal swabs as a viable alternative to faecal sampling for the analysis of gut microbiota functionality and composition

Faecal or biopsy samples are frequently used to analyse the gut microbiota, but issues remain with the provision and collection of such samples. Rectal swabs are widely-utilised in clinical practice and previous data demonstrate their potential role in microbiota analyses; however, studies to date have been heterogenous, and there is a particular lack of data concerning the utility of swabs for the analysis of the microbiota’s functionality and metabolome. We compared paired stool and rectal swab samples from healthy individuals to investigate whether rectal swabs are a reliable proxy for faecal sampling. There were no significant differences in alpha and beta diversity measures between swab and faecal samples, and inter-subject variability was preserved. Additionally, no significant differences were demonstrated in abundance of major annotated phyla. Inferred gut functionality using Tax4Fun2 showed excellent correlation between the two sampling techniques (Pearson’s coefficient r = 0.9217, P  < 0.0001). Proton nuclear magnetic resonance ( 1 H NMR) spectroscopy enabled the detection of 20 metabolites with good correlation between rectal swab and faecal samples for butyrate, succinate and 5-aminovalerate relative abundances, though more variable degrees of association for other identified metabolites. These data support the utility of rectal swabs in both compositional and functional analyses of the gut microbiota