Rarefied flow past a flat plate at incidence

Results of a numerical study using the direct simulation Monte Carlo (DSMC) method are presented for the transitional flow about a flat plate at 40 deg incidence. The plate has zero thickness and a length of 1.0 m. The flow conditions simulated are those experienced by the Shuttle Orbiter during reentry at 7.5 km/s. The range of freestream conditions are such that the freestream Knudsen number values are between 0.02 and 8.4, i.e., conditions that encompass most of the transitional flow regime. The DSMC simulations show that transitional effects are evident when compared with free molecule results for all cases considered. The calculated results demonstrate clearly the necessity of having a means of identifying the effects of transitional flow when making aerodynamic flight measurements as are currently being made with the Space Shuttle Orbiter vehicles. Previous flight data analyses have relied exclusively on adjustments in the gas-surface interaction models without accounting for the transitional effect which can be comparable in magnitude. The present calculations show that the transitional effect at 175 km would increase the Space Shuttle Orbiter lift-drag ratio by 90 percent over the free molecule value

Takayasu’s arteritis in pregnancy: a rare case report from BJGMC and Sassoon Hospital Pune, Maharashtra, India

Takayasu’s arteritis is a chronic idiopathic vasculitis affecting aorta and its primary branches, commonly seen in young women of Asian or oriental descent during child bearing age. Incidence is 2.6 cases/million/year. It affects females in the reproductive years accounting for almost 80% of the cases. A 34 year female G2P1L1 with 9 months of amenorrhea with previous LSCS known case of takayasu arteritis, epilepsy with right side hemiparesis with aphasia. She proceeded to have elective LSCS with ventouse delivery under epidural anaesthesia and delivered alive healthy female baby weight 2.4 kg and patient was transferred to intensive care unit for observation for 48 hrs. patients intrapartum post partum period was uneventful and discharged after 1month with cardiology fitness. Pregnancy with takayasu arteritis (pulseless disease) requires a multidisciplinary management from gynaecologist, cardiologist, neurologist for favourable maternal and fetal outcome

Knowledge and attitude of medical undergraduate, interns and postgraduate students towards emergency contraception

 Background: Although India was the first country in the world to have national family planning policy, the acceptance of contraceptive methods has been unsatisfactory. Many women in their peak reproductive years, who wish to control their fertility, are not aware about the different methods of contraceptives available. Unregulated fertility results in unplanned pregnancies. Emergency contraceptive pills can avoid many such unplanned pregnancies. The study was to assess the knowledge and attitude about emergency contraception (EC) among the undergraduate, interns and postgraduate medical science university students.Methods: A cross sectional study was carried out among 180 medical students which include undergraduate, interns, and postgraduate students (60 from each group) studying at BJ Medical College, Pune, Maharashtra by a convenient sample method over a period of August 2016 to November 2016. Data were collected by pre-designed, pre-tested, self-administered questionnaire. Data was analyzed in the form of percentage and proportions and Chi square test was applied.Results: In this study, a total of 180 respondents, of which 110 (61.2%) were male and 70 (38.8%) were female. The knowledge about EC was highest (47.6%) among postgraduates in comparison to interns (43.3%) and undergraduate students (41.6%). Overall positive attitude toward EC was observed among 73.8% of the respondents.Conclusions: Considering the role of a medical graduate as counselor and health care provider, the technical knowledge about different aspects of EC among the study population was inadequate

DSMC simulations of Mach 20 nitrogen flows about a 70 degree blunted cone and its wake

Numerical results obtained with the direct simulation Monte Carlo (DSMC) method are presented for Mach 20 nitrogen flow about a 70-deg blunted cone. The flow conditions simulated are those that can be obtained in existing low-density hypersonic wind tunnels. Three sets of flow conditions are simulated with freestream Knudsen numbers ranging from 0.03 to 0.001. The focus is to characterize the wake flow under rarefied conditions. This is accomplished by calculating the influence of rarefaction on wake structure along with the impact that an afterbody has on flow features. This data report presents extensive information concerning flowfield features and surface quantities

Non-linear IVIV characteristics in two-dimensional superconductors: Berezinskii-Kosterlitz-Thouless physics vs inhomogeneity

One of the hallmarks of the Berezinskii-Kosterlitz-Thouless (BKT) transition in two-dimensional (2D) superconductors is the universal jump of the superfluid density, that can be indirectly probed via the non-linear exponent of the current-voltage $IV$ characteristics. Here, we compare the experimental measurements of $IV$ characteristics in two cases, namely NbN thin films and SrTiO$_3$-based interfaces. While the former display a paradigmatic example of BKT-like non-linear effects, the latter do not seem to justify a BKT analysis. Rather, the observed $IV$ characteristics can be well reproduced theoretically by modelling the effect of mesoscopic inhomogeneity of the superconducting state. Our results offer an alternative perspective on the spontaneous fragmentation of the superconducting background in confined 2D systems.Comment: Final version, as publishe

DSMC calculations for 70-deg blunted cone at 3.2 km/s in nitrogen

Numerical results obtained with the direct simulation Monte Carlo (DSMC) method are presented for Mach 15.6 nitrogen flow about a 70-deg spherically blunted cone at zero incidence. This flow condition is one of several generated in the Large Energy National Shock (LENS) tunnel during tests of a 15.24 cm diameter model with an afterbody sting. The freestream Knudsen number, based on model diameter, is 0.0023. The focus of the DSMC calculations is to characterize the near wake flow under conditions where rarefaction effects may influence afterbody aerothermal loads. This report provides information concerning computational details along with flowfield and surface quantities. Calculations show that the flow enveloping the test model is in thermal nonequilibrium and a sizable vortex develops in the near wake. Along the model baseplane the heating rates are about 0.6 percent of the forebody stagnation value while the maximum heating along the sting is about 4.2 percent of the forebody stagnation value. Comparison of a Navier-Stokes solution with the present calculations show good agreement for surface heating, pressure, and skin friction results