165 research outputs found
Study of non-equilibrium transport phenomena
Nonequilibrium phenomena due to real gas effects are very important features of low density hypersonic flows. The shock shape and emitted nonequilibrium radiation are identified as the bulk flow behavior parameters which are very sensitive to the nonequilibrium phenomena. These parameters can be measured in shock tubes, shock tunnels, and ballistic ranges and used to test the accuracy of computational fluid dynamic (CFD) codes. Since the CDF codes, by necessity, are based on multi-temperature models, it is also desirable to measure various temperatures, most importantly, the vibrational temperature. The CFD codes would require high temperature rate constants, which are not available at present. Experiments conducted at the NASA Electric Arc-driven Shock Tube (EAST) facility reveal that radiation from steel contaminants overwhelm the radiation from the test gas. For the measurement of radiation and the chemical parameters, further investigation and then appropriate modifications of the EAST facility are required
Vaginal delivery at term with previous one cesarean section: is it safe?
Background: Post cesarean pregnancies are high risk pregnancy and main concern is uterine scar rupture with increasing maternal and perinatal risks, for vaginal birth after cesarean delivery (VBAC). Objective of this study is to know neonatal and maternal outcome at term who attempt vaginal delivery with previous one cesarean section presenting in active stage of labor.Methods: A total of 277 pregnant women with single live fetus at term, cephalic presentation with previous one cesarean section, underwent a trial of labor and outcome of successful and failed vaginal birth were noted.Results: Trial of labor was successful in 52.3% and failed in 47.7% (p=0.269). VBAC was successful where the previous cesarean section indications were fetal distress (79% versus 21%, p=0.000), pregnancy induced hypertension (77.3% versus 22.7%, p=0.000) and fetal growth restriction (81.8% versus 18.2%, p=0.000), when compared with failed trial of labor who required emergency cesarean section in pre-labor rupture of the membranes (8.3% versus 91.7%, p=0.000) and dystocia (3.3% versus 96.7%, p=0.000). VBAC was successful at gestational age of 37 0/7-38 6/7 weeks (p=0.000). In the failed VBAC women who required emergency cesarean section there was significant early neonatal death (p=0.025). Scar dehiscence and hospital stay with or without complications were more in the failed VBAC group.Conclusions: Early neonatal death and duration of hospital stay were significantly more in the failed VBAC, who were posted for emergency cesarean delivery. Scar dehiscence occurred in the failed VBAC group. Women presenting at 37 0/7 to 38 6/7 weeks of gestation with cephalic presentation in active stage of labor who had previous cesarean section done for fetal distress, pregnancy induced hypertension and fetal growth restriction with inter pregnancy interval of > 24 months can be planned and counselled for VBAC trial of labor
Experimental program for real gas flow code validation at NASA Ames Research Center
The experimental program for validating real gas hypersonic flow codes at NASA Ames Rsearch Center is described. Ground-based test facilities used include ballistic ranges, shock tubes and shock tunnels, arc jet facilities and heated-air hypersonic wind tunnels. Also included are large-scale computer systems for kinetic theory simulations and benchmark code solutions. Flight tests consist of the Aeroassist Flight Experiment, the Space Shuttle, Project Fire 2, and planetary probes such as Galileo, Pioneer Venus, and PAET
Computations of Axisymmetric Flows in Hypersonic Shock Tubes
A time-accurate two-dimensional fluid code is used to compute test times in shock tubes operated at supersonic speeds. Unlike previous studies, this investigation resolves the finer temporal details of the shock-tube flow by making use of modern supercomputers and state-of-the-art computational fluid dynamic solution techniques. The code, besides solving the time-dependent fluid equations, also accounts for the finite rate chemistry in the hypersonic environment. The flowfield solutions are used to estimate relevant shock-tube parameters for laminar flow, such as test times, and to predict density and velocity profiles. Boundary-layer parameters such as bar-delta(sub u), bar-delta(sup *), and bar-tau(sub w), and test time parameters such as bar-tau and particle time of flight t(sub f), are computed and compared with those evaluated by using Mirels' correlations. This article then discusses in detail the effects of flow nonuniformities on particle time-of-flight behind the normal shock and, consequently, on the interpretation of shock-tube data. This article concludes that for accurate interpretation of shock-tube data, a detailed analysis of flowfield parameters, using a computer code such as used in this study, must be performed
Planned versus emergency cesarean delivery with previous one cesarean section: a prospective observational study
Background: Women presents with previous history of cesarean section (CS) is a ‘high risk pregnancy’ and requires regular antenatal check-ups. Planned CS at term done for perinatal interest. Post cesarean pregnancy admitted through emergency required direct CS, for those not fit for vaginal birth as per different guidelines. Main objective of this study is to know neonatal and maternal outcome at term for planned versus emergency CS with previous one CS.Methods: Planned or emergency CS were done in 1003 pregnant women at term with previous one CS and outcome of both neonatal and maternal were noted. Emergency CS done in failed VBAC women were excluded from the study.Results: Planned CS before onset of labor were done in 22.93% and emergency CS in 77.07% in the present study. A significant number of women has undergone planned CS in cephalo-pelvic disproportion (45.21%), contracted pelvis (24.34%) and fetal growth restriction (6.95%) where P=0.000. Scar tenderness (20.18%), fetal distress (16.04%) and cephalo-pelvic disproportion (15.52%) were major indications for emergency CS. Maternal complications in the emergency CS group were pyrexia (P=0.000) and blood transfusion, required in 1.81% (P=0.000). There were two maternal death and hysterectomy required in 0.38% in the emergency CS compared to 1.30% in the planned CS (P=0.274). Neonatal complications were significant(P=0.018) in the emergency CS group. Common complications were jaundice (2.84% versus 1.73%, P=0.489), sepsis (0.25% versus 0.86%, P=0.487) and early neonatal death (2.97% versus 0.86%, P=0.119) in emergency CS compared to planned CS.Conclusions: Neonatal morbidity and mortality were significant in the emergency CS, compared to planned CS. Pyrexia and blood transfusion were significant maternal morbidity in the emergency CS group
Sensor for monitoring plasma parameters
A spectrally tunable VCSEL (vertical cavity surface-emitting laser) was used
as part of sensing hardware for measurements of the radial-integrated gas
temperature inside an inductively coupled plasma reactor. The data were
obtained by profiling the Doppler-broadened absorption of metastable Ar atoms
at 763.51 nm in argon and argon/nitrogen plasmas (3, 45, and 90% N2 in Ar) at
pressure 0.5-70 Pa and inductive power of 100 and 300 W. The results were
compared to rotational temperature derived from the N2 emission at the (0,0)
transition of the C - B system. The differences in integrated rotational and
Doppler temperatures were attributed to non-uniform spatial distributions of
both temperature and thermometric species (Ar* and N2*) that varied depending
on conditions. A two-dimensional, two-temperature fluid plasma simulation was
employed to explain these differences. This work should facilitate further
development of a miniature sensor for non-intrusive acquisition of data
(temperature and densities of multiple plasma species) during micro- and
nano-fabrication plasma processing, thus enabling the diagnostic-assisted
continuous optimization and advanced control over the processes. Such sensors
would also enable tracking the origins and pathways of damaging contaminants,
thereby providing real-time feedback for adjustment of processes. Our work
serves as an example of how two line-of-sight integrated temperatures derived
from different thermometric species make it possible to characterize the radial
non-uniformity of the plasma.Comment: Presented at the Photonics West conference, Lasers and Applications
in Science and Technology, San Jose, CA, January 2004. This version gives a
more detailed introduction on diode lasers as diagnostic tool for
micro/nano-fabrication. A follow-up paper published in Plasma Sources Sci.
Technol., v.13, 691-700 (2004) featured improvements in plasma simulatio
Atomic Resonance Radiation Energetics Investigation as a Diagnostic Method for Non-Equilibrium Hypervelocity Flows
Absorption measurements with a tunable vacuum ultraviolet light source have been proposed as a concentration diagnostic for atomic oxygen, and the viability of this technique is assessed in light of recent measurements. The instrumentation, as well as initial calibration measurements, have been reported previously. We report here additional calibration measurements performed to study the resonance broadening line shape for atomic oxygen. The application of this diagnostic is evaluated by considering the range of suitable test conditions and requirements, and by identifying issues that remain to be addressed
Dynamics of socio-economic factors affecting climate vulnerability and technology adoption: Evidence from Jodhpur district of Rajasthan
192-196Climate change and extreme weather fluctuations are the most threatening challenges to the farming communities especially in semi-arid tropics. The paper investigates socio-economic factors affecting vulnerability and adoption of innovations using micro-level survey data of 100 systematically selected farmers in the Jodhpur district of Rajasthan, India. The results reveal that higher income, irrigation and provision of seeds reduce climate vulnerability to a great extent. Several farm level strategies have been adopted by the farmers against climate induced stress, including change in cropping pattern, reduction in irrigation usage, use of drips and sprinklers and water conservation. In case of pearl millet cropping system, we found that adoption of wide row spacing is significantly influenced by the level of the farmer’s education, land size category, climate awareness and trainings programs. The study suggests that diversified crop sequence involving pearl millet-wheat-cluster bean-barley-onion, farmers’ adoption of suitable adaptation strategies and climate resilient technologies will improve with better awareness, education and farm governance with regard to climate change. Moreover, technologies especially indigenous ones suitable to the local contextual needs must be developed or fine-tuned and disseminated for reducing climate-induced vulnerability
Dynamics of socio-economic factors affecting climate vulnerability and technology adoption: Evidence from Jodhpur district of Rajasthan
Climate change and extreme weather fluctuations are the most threatening challenges to the farming communities especially in semi-arid tropics. The paper investigates socio-economic factors affecting vulnerability and adoption of innovations using micro-level survey data of 100 systematically selected farmers in the Jodhpur district of Rajasthan, India. The results reveal that higher income, irrigation and provision of seeds reduce climate vulnerability to a great extent. Several farm level strategies have been adopted by the farmers against climate induced stress, including change in cropping pattern, reduction in irrigation usage, use of drips and sprinklers and water conservation. In case of pearl millet cropping system, we found that adoption of wide row spacing is significantly influenced by the level of the farmer’s education, land size category, climate awareness and trainings programs. The study suggests that diversified crop sequence involving pearl millet-wheat-cluster bean-barley-onion, farmers’ adoption of suitable adaptation strategies and climate resilient technologies will improve with better awareness, education and farm governance with regard to climate change. Moreover, technologies especially indigenous ones suitable to the local contextual needs must be developed or fine-tuned and disseminated for reducing climate-induced vulnerability
Loss of genetic diversity and inbreeding in Kashmir red deer (Cervus elaphus hanglu) of Dachigam National Park, Jammu & Kashmir, India
BACKGROUND: Hangul (Cervus elaphus hanglu), the eastern most subspecies of red deer, is now confined only to the mountains in the Kashmir region of Jammu & Kashmir State of India. It is of great conservation significance as this is the last and only hope for Asiatic survivor of the red deer species in India. Wild population of free ranging hangul deer inhabiting in and around Dachigam National Park was genetically assessed in order to account for constitutive genetic attributes of hangul population using microsatellite markers. RESULTS: In a pool of 36 multi-locus genotypes, 30 unique individuals were identified based on six microsatellite loci. The estimated cumulative probability of identity assuming all individuals were siblings (P(ID) sibs) was 0.009 (9 in 1000). Altogether, 49 different alleles were observed with mean (± s.e.) allelic number of 8.17 ± 1.05, ranging from 5 to 11 per locus. The observed heterozygosity ranged between 0.08 and 0.83, with mean 0.40 ± 0.11 and the inbreeding coefficient ranged between −0.04 and 0.87 with mean 0.38 ± 0.15. Majority of loci (5/6) were found to be informative (PIC value > 0.5). All loci deviated from Hardy-Weinberg equilibrium except Ca-38 (P > 0.05) and none of the pairs of loci showed significant linkage disequilibrium except the single pair of Ca-30 and Ca-43 (P < 0.05). CONCLUSIONS: The preliminary findings revealed that hangul population is significantly inbred and exhibited a low genetic diversity in comparison to other deer populations of the world. We suggest prioritizing the potential individuals retaining high heterozygosity for ex situ conservation and genetic monitoring of the hangul population should be initiated covering the entire distribution range to ensure the long term survival of hangul. We speculate further ignoring genetics attributes may lead to a detrimental effect which can negatively influence the reproductive fitness and survivorship of the hangul population in the wild
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