Catalytic Reactive Distillation for the Esterification Process: Experimental and Simulation

In the present study, methyl acetate has been synthesized using esterification of acetic acid with methanol in a continuous packed bed catalytic reactive distillation column in the presence of novel Indion 180 ion exchange resin solid catalyst. The experiments were conducted at various operating conditions like reboiler temperature, reflux ratio, and different feed flow rates of the acetic acid and methanol. The non-ideal pseudo-homogeneous kinetic model has been developed for esterification of acetic acid with methanol in the presence of Indion 180 catalyst. The developed kinetic model was used for the simulation of the reactive distillation column for the synthesis of methyl acetate using equilibrium stage model in Aspen Plus version 7.3. The simulation results were compared with experimental results, and found that there is a good agreement between them. The sensitivity analyses were also carried out for the different parameters of bottom flow rate, feed temperatures of acetic acid and methanol, and feed flow rate of acetic acid and methanol. This work is licensed under a Creative Commons Attribution 4.0 International License

Subwavelength atom localization via amplitude and phase control of the absorption spectrum

We propose a scheme for subwavelength localization of an atom conditioned upon the absorption of a weak probe field at a particular frequency. Manipulating atom-field interaction on a certain transition by applying drive fields on nearby coupled transitions leads to interesting effects in the absorption spectrum of the weak probe field. We exploit this fact and employ a four-level system with three driving fields and a weak probe field, where one of the drive fields is a standing-wave field of a cavity. We show that the position of an atom along this standing wave is determined when probe field absorption is measured. We find that absorption of the weak probe field at a certain frequency leads to subwavelength localization of the atom in either of the two half-wavelength regions of the cavity field by appropriate choice of the system parameters. We term this result as sub-half-wavelength localization to contrast it with the usual atom localization result of four peaks spread over one wavelength of the standing wave. We observe two localization peaks in either of the two half-wavelength regions along the cavity axis.Comment: Accepted for publication to Physical Review

Risk factors and perinatal outcome associated with low birth weight in a prospective cohort: is there a shift towards sustainable developmental goal 3

Background: Low birth weight is a socio, economic, cultural and community based health issue which reflects responsibility and commitment of local and national administrative authorities. It continues to be a cause of short and long term adverse perinatal outcome with a bearing on adult non communicable health risks.Methods: This is a prospective observational and analytic study to know the prevalence, risk factors and perinatal outcome of LBW, from July 2017 to December 2018 in department of Obstetrics and Gynecology, MIMS Medical College, Andhra Pradesh, India. Maternal risk factors and outcomes associated with LBW were defined through risk ratios.Results: 721 infants including 116 LBW and 605 NBW born during study period were included in the study. Prevalence of LBW was 16%. Preterm birth accounted for 35%, FGR for 13.8% and SGA for 51.2% of them. Maternal factors like age 35years, social status II to IV, below higher secondary education, house maker, primi gravida, grand multi para, BMI 24.9kg/M2, Hb<11 gm% were having higher RR for LBW. LBW infants showed frequent association with oligo or polyhydramnious and hemorrhagic or turbid amniotic fluid. They had higher risks for non reassuring fetal heart rate changes, for induced delivery or an elective caesarean section. More often they needed NICU care for longer duration and showed a higher risk for malformations and neonatal mortality. Overall perinatal mortality was 5.54 per 1000 live birth.Conclusions: LBW is a risk factor for neonatal morbidity and mortality; which can be minimised by institutional delivery. High prevalence PTB (35%) warrants obstetricians to be more vigilant about indentifying the risk factors and adequate management planning. Constitutionally small baby at birth probably needs redefining normal birth weight for different ethnicity

Review paper: Application of the Pulsed Eddy Current Technique to Inspect Pipelines of Nuclear Plants

Local wall thinning in pipelines affects the structural integrity of industries, such as nuclear power plants (NPPs). In the present study, a development of pulsed eddy current (PEC) technology that detects the wall thinning of pipelines covered with insulation is reviewed. The methods and experimental results, which have two kinds of probe with a single and double core, were compared. For this purpose, the single and double core probes having one and two excitation coils have been devised, and the differential probe with two Hall sensors has been fabricated to measure the wall thinning in insulated pipelines. The test sample is a stainless steel having different thickness, laminated by plastic insulation to simulate the pipelines in NPPs. The excitation coils in the probe is driven by a rectangular current pulse, the difference of two Hall sensors has been measured as a resultant PEC signal. The peak value of the detected signal is used to describe the wall thinning. The double core probe has better performance to detect the wall thinning covered with insulation; the single core probe can detect the wall thinning up to an insulation thickness of 18 mm, whereas the double probe can detect up to 25 mm. The results show that the double core PEC probe has the potential to detect the wall thinning in an insulated pipeline of the NPPs

Prediction of the Atomization Energy of Molecules Using Coulomb Matrix and Atomic Composition in a Bayesian Regularized Neural Networks

Exact calculation of electronic properties of molecules is a fundamental step for intelligent and rational compounds and materials design. The intrinsically graph-like and non-vectorial nature of molecular data generates a unique and challenging machine learning problem. In this paper we embrace a learning from scratch approach where the quantum mechanical electronic properties of molecules are predicted directly from the raw molecular geometry, similar to some recent works. But, unlike these previous endeavors, our study suggests a benefit from combining molecular geometry embedded in the Coulomb matrix with the atomic composition of molecules. Using the new combined features in a Bayesian regularized neural networks, our results improve well-known results from the literature on the QM7 dataset from a mean absolute error of 3.51 kcal/mol down to 3.0 kcal/mol.Comment: Under review ICANN 201

Galbladder perforation: The importance of standardised treatment algorithms

Von H. Barfo

Effects of the Nearest-Neighbour Coulomb Interactions on the Ground State of the Periodic Anderson Model

The magnetic and non-magnetic ground states of the periodic Anderson model with Coulomb interaction between $f$-electrons on the nearest-neighbour(NN) sites are investigated using a variational method, which gives exact calculation of the expectation values in the limit of infinite dimensions. It is shown that for a critical value of NN Coulomb interactions the magnetic ground state of the periodic Anderson model in the Kondo regime is unstable. Factors in terms of the physical processes responsible for instability of the magnetic ground state are also discussed. Our study indicates the importance of the NN Coulomb interactions for correlated two band models.Comment: RevTeX, 6 pages, 5 figures, to appear in Phys. Rev.

Isotope Effect in the Presence of Magnetic and Nonmagnetic Impurities

The effect of impurities on the isotope coefficient is studied theoretically in the framework of Abrikosov-Gor'kov approach generalized to account for both potential and spin-flip scattering in anisotropic superconductors. An expression for the isotope coefficient as a function of the critical temperature is obtained for a superconductor with an arbitrary contribution of spin-flip processes to the total scattering rate and an arbitrary degree of anisotropy of the superconducting order parameter, ranging from isotropic s-wave to d-wave and including anisotropic s-wave and mixed (s+d)-wave as particular cases. It is found that both magnetic and nonmagnetic impurities enhance the isotope coefficient, the enhancement due to magnetic impurities being generally greater than that due to nonmagnetic impurities. From the analysis of the experimental results on La-Sr-Cu-M-O high temperature superconductor, it is concluded that the symmetry of the pairing state in this system differs from a pure d-wave.Comment: 4 pages, 3 figure