Diffuse interface models of solidification with convection: The choice of a finite interface thickness

The thin interface limit aims at minimizing the effects arising from a numerical interface thickness, inherent in diffuse interface models of solidification and microstructure evolution such as the phase field model. While the original formulation of this problem is restricted to transport by diffusion, we consider here the case of melt convection. Using an analysis of the coupled phase field-fluid dynamic equations, we show here that such a thin interface limit does also exist if transport contains both diffusion and convection. This prediction is tested by comparing simulation studies, which make use of the thin-interface condition, with an analytic sharp-interface theory for dendritic tip growth under convection. © 2020, The Author(s)

A thoracophagus conjoined twins with myelomeningocele: an unusual case

Conjoined twins represent one of the rarest forms of twin gestation. Conjoined twinning is rare, occurring in about 1% of monochorionic twins with an estimated incidence ranging from 1:30,000 to 1:2,00,000 live births and 1 in 650 to 900 twin deliveries. A 21 year old gravida 2, with an abortion, a resident of Ginjakheda, Deoli Wardha came to our hospital, AVBRH Sawangi and presented with history of amenorrhoea of six months. She had her first ultrasonography done which demonstrated thoracophagus conjoined twins. Patient was admitted in view of management of conjoined twins. She was posted for elective caesarean section on 5/11/11. A conjoined twin of combined weight around 2 kgs was extracted out. Both the foetuses were female with multiple congenital anomalies. In conclusion, conjoined twins are associated with a high perinatal mortality; therefore making an early diagnosis by means of ultrasonography, gives parents a chance to elect pregnancy termination

Convulsions in early post-partum period, a diagnostic dilemma

Neurocysticercosis is the most common helminthic (tapeworm) infection of the brain worldwide. It presents as hydrocephalus and acute onset seizures. A 28-year-old para 3 live 3 [P3L3], post-partum [day 7], resident of Arvi, presented in casualty during emergency hours with headache and fever since 7 days. She presented with h/o convulsions 2 episodes, one on day 5 and one on day 7 of her full term vaginal home delivery. She presented to the Emergency Department on day 7 with generalised tonic-clonic seizures preceded by nausea and headache. All her blood investigations were within normal limits except an extremely surprising finding on CT scan. 40% of patients having postpartum convulsions do not experience preeclampsia, clinical awareness is essential for early treatment and care

Successful maternal and fetal outcome of Guillain-Barre syndrome complicating pregnancy: a case report

Guillain-Barré syndrome rarely complicates pregnancy, incidence being 2/100000 population. We report a case of 23-year-old 2nd gravida who developed a progressive ascending paralysis during the second trimester of pregnancy. The worsening of the respiratory insufficiency required transfer to an intensive care unit but did not require artificial ventilation. Cerebrospinal fluid examination revealed albumin-cytological dissociation and repeated electrophysiological studies showed typical features of demyelinating neuropathy with conduction blocks. Biological investigations, especially CMV and campylobacter jejuni serologies, were all negative. Intravenous immunoglobulin infusions resulted in rapid improvement in the patient. This case raises the question of the relationship between the Guillain-Barré syndrome and pregnancy. The occurrence of the disease, as well as the rapid recovery in antenatal period could be consecutive to a partial failure of the maternal immunological tolerance toward the fetus

Ultrasound intensification suppresses the need of methanol excess during the biodiesel production with Lipozyme TL-IM

The synthesis of biodiesel from sunflower oil and methanol based on transesterification using the immobilized lipase from Thermomyces lanuginosus (Lipozyme TL-IM) has been investigated under silent conditions and under an ultrasound field. Ultrasound assisted process led to reduced processing time and requirement of lower enzyme dosage. We found for the first time that ratio 1:3 (oil to methanol) was favoured for the ultrasound assisted enzymatic process which is lower as that favoured for the silent process (ratio of 1.4). Our results indicate that intensification provided by ultrasound suppresses the need of the excess of the methanol reactant during the enzymatic biodiesel production. Ultrasound assisted enzymatic biodiesel production is therefore a faster and a cleaner processes.The authors acknowledge Brenntag India Pvt. Ltd. for kindly providing gift sample of lipase enzyme Lipozyme TL IM to carry out the research work. All authors acknowledge the funding of Department of Science and Technology and Portuguese Science Foundation under the Indo-Portuguese collaborative program

Thin interface limit of the double-sided phase-field model with convection

The thin interface limit of the phase-field model is extended to include transport via melt convection. A double-sided model (equal diffusivity in liquid and solid phases) is considered for the present analysis. For the coupling between phase-field and Navier-Stokes equations, two commonly used schemes are investigated using a matched asymptotic analysis: (i) variable viscosity and (ii) drag force model. While for the variable viscosity model, the existence of a thin interface limit can be shown up to the second order in the expansion parameter, difficulties arise in satisfying no-slip boundary condition at this order for the drag force model. Nevertheless, detailed numerical simulations in two dimensions show practically no difference in dendritic growth profiles in the presence of forced melt flow obtained for the two coupling schemes. This suggests that both approaches can be used for the purpose of numerical simulations. Simulation results are also compared to analytic theory, showing excellent agreement for weak flow. Deviations at higher fluid velocities are discussed in terms of the underlying theoretical assumptions. © 2020 The Author(s) Published by the Royal Society. All rights reserved.European Space Agency, ESADeutsche Forschungsgemeinschaft, DFGRussian Science Foundation, RSF: 16-11-10095Deutsche Forschungsgemeinschaft, DFGData accessibility. This article has no additional data. Authors’ contributions. All the authors have contributed equally to this work. Competing interests. We declare we have no competing interest. Funding. P.K.G. acknowledges the support by the European Space Agency (ESA) under research project MULTIPHAS grant no. (AO-2004) and the German Aerospace Center (DLR) Space Management undercontract no. 50WM1541 and also from the Russian Science Foundation under project no. 16-11-10095. A.S. and F.V. acknowledges financial support by the German Research Foundation (DFG) under the project no. Va205/17-1

Magnetic excitations of Fe_{1+y}Se_xTe_{1-x} in magnetic and superconductive phases

We have used inelastic neutron scattering and muon-spin rotation to compare the low energy magnetic excitations in single crystals of superconducting Fe1.01Se0.50Te0.50 and non-superconducting Fe1.10Se0.25Te0.75. We confirm the existence of a spin resonance in the superconducting phase of Fe1.01Se0.50Te0.50, at an energy of 7 meV and a wavevector of (1/2,1/2,0). The non-superconducting sample exhibits two incommensurate magnetic excitations at (1/2,1/2,0)\pm(0.18,-0.18,0) which rise steeply in energy, but no resonance is observed at low energies. A strongly dispersive low-energy magnetic excitation is also observed in Fe1.10Se0.25Te0.75 close to the commensurate antiferromagnetic ordering wavevector (1/2-\delta,0,1/2) where \delta \approx 0.03. The magnetic correlations in both samples are found to be quasi-two dimensional in character and persist well above the magnetic (Fe1.10Se0.25Te0.75) and superconducting (Fe1.01Se0.50Te0.50) transition temperatures.Comment: 10 pages, 4 figure

Factors affecting job choice among physician anesthesia providers in Uganda: a survey of income composition, discrete choice experiment, and implications for the decision to work rurally

Abstract Background One of the biggest barriers to accessing safe surgical and anesthetic care is lack of trained providers. Uganda has one of the largest deficits in anesthesia providers in the world, and though they are increasing in number, they remain concentrated in the capital city. Salary is an oft-cited barrier to rural job choice, yet the size and sources of anesthesia provider incomes are unclear, and so the potential income loss from taking a rural job is unknown. Additionally, while salary augmentation is a common policy proposal to increase rural job uptake, the relative importance of non-monetary job factors in job choice is also unknown. Methods A survey on income sources and magnitude, and a Discrete Choice Experiment examining the relative importance of monetary and non-monetary factors in job choice, was administered to 37 and 47 physician anesthesiologists in Uganda, between May–June 2019. Results No providers worked only at government jobs. Providers earned most of their total income from a non-government job (50% of income, 23% of working hours), but worked more hours at their government job (36% of income, and 44% of working hours). Providers felt the most important job attributes were the quality of the facility and scope of practice they could provide, and the presence of a colleague (33% and 32% overall relative importance). These were more important than salary and living conditions (14% and 12% importance). Conclusions No providers accepted the salary from a government job alone, which was always augmented by other work. However, few providers worked only nongovernment jobs. Non-monetary incentives are powerful influencers of job preference, and may be leveraged as policy options to attract providers. Salary continues to be an important driver of job choice, and jobs with fewer income generating opportunities (e.g. private work in rural areas) are likely to need salary augmentation to attract providers

One-pot synthesis of multifunctional ZnO nanomaterials: study of superhydrophobicity and UV photosensing property

ZnO nanomaterials are synthesized using one-pot synthesis method. Equimolar solution of Zinc Nitrate hexahydrate (Zn(NO3)(2).6H(2)O) and Hexamethylenetetramine (C6H12N4) is used as a precursor for ZnO formation. Different nanostructures of ZnO are achieved by controlling the pH of the growth solution in the range 2-12 (acidic to alkali). ZnO nanostructures are evaluated for hydrophobic property using static contact angle measurement setup and UV photosensing activity. Surface morphology, structural properties and compositional analysis of ZnO nanostructures are examined by field emission scanning electron microscope (FE-SEM), energy dispersive X-ray analysis (EDX), high-resolution transmission electron microscope (FEG-TEM) and X-ray diffraction (XRD) measurements. Existence of ZnO wurtzite structure is confirmed from XRD study and is analyzed by Rietveld refinement method. Nanomaterials are characterized using Raman spectroscopy which confirms highest oxygen deficiency in ZnO nanorods. The material shows remarkable superhydrophobic and UV photosensing property and hence the name multifunctional. Among all morphologies grown at different pH values, ZnO nanorods show superhydrophobic nature with contact angle more than 170 degrees. Total surface energy value of ZnO nanostructures is calculated using Wendt two-component theory. Different ZnO nanostructures (with variation of pH value) are used to study UV photosensing property. Responsivity and photocurrent show a strong dependence on the morphology of ZnO