Modeling of an Interconnected Fluidized Bed Reactor for Chemical Looping Combustion

Chemical Looping Combustion (CLC) is comprised of two reactors, in which direct contact between air and fuel is avoided. A metal oxide, as oxygen carrier, transports oxygen from the air reactor to the fuel reactor while circulating between them. Based on the hydrodynamics coupled with reaction kinetics of oxygen carrier from the literature, a model for an interconnected fluidized bed reactor has been developed to optimize the design and operation of the reactor system. The model considers the chemical reaction of a single particle and a particle population balance for the calculation of bed particle conversion. The core-annulus and two-phase hydrodynamic models are assumed for the air and fuel reactors, respectively. Predictions of the oxygen emission, particle conversion and fuel conversion efficiency under different operating conditions are presented for a pilot scale CLC reactor system

Pheochromocytoma Presenting with Hypertensive Encephalopathy in a 12-Year-Old Boy

Although pheochromocytoma is rare in children, it could result in hypertensive emergency. We describe the case of a 12-year-old boy with pheochromocytoma. His clinical manifestations indicated hypertensive encephalopathy; however, there were no space-occupying lesion in the brain and definitive evidence of secondary cause of hypertension. Knowing that he had extremely high blood pressure, headache, palpitation, and perspiration rendered sympathetic crisis a presumptive diagnosis. Subsequently, pheochromocytoma was diagnosed by computed tomography and catecholamine assay. After stabilizing the blood pressure with antihypertensive medications, such as phenoxybenzamine, laparoscopic adrenalectomy was performed, and he was discharged without residual discomfort. We would like to highlight expeditious diagnosis and proper management of pheochromocytoma with hypertensive encephalopathy

Scarred Resonances and Steady Probability Distribution in a Chaotic Microcavity

We investigate scarred resonances of a stadium-shaped chaotic microcavity. It is shown that two components with different chirality of the scarring pattern are slightly rotated in opposite ways from the underlying unstable periodic orbit, when the incident angles of the scarring pattern are close to the critical angle for total internal reflection. In addition, the correspondence of emission pattern with the scarring pattern disappears when the incident angles are much larger than the critical angle. The steady probability distribution gives a consistent explanation about these interesting phenomena and makes it possible to expect the emission pattern in the latter case.Comment: 4 pages, 5 figure

Directional interacting whispering gallery modes in coupled dielectric microdisks

We study the optical interaction in a coupled dielectric microdisks by investigating the splitting of resonance positions of interacting whispering gallery modes (WGMs) and their pattern change, depending on the distance between the microdisks. It is shown that the interaction between the WGMs with odd parity about y-axis becomes appreciable at a distance less than a wavelength and causes directional emissions of the resulting interacting WGMs. The directionality of the interacting WGMs can be understood in terms of an effective boundary deformation in ray dynamical analysis. We also discuss about the oscillation of the splitting when the distance is greater than a wavelength.Comment: 7 pages, 10 figure

A 9-year-old Korean girl with Fontaine progeroid syndrome: a case report with further phenotypical delineation and description of clinical course during long-term follow-up

Background Gorlin–Chaudhry–Moss syndrome (GCMS) and Fontaine–Farriaux syndrome (FFS) are extremely rare genetic disorders that share similar clinical manifestations. Because a de novo missense mutation of the solute carrier family 25 member 24 (SLC25A24) gene was suggested to be the common genetic basis of both syndromes, it has been proposed recently that they be integrated into a single disorder under the name of Fontaine progeroid syndrome (FPS). Case presentation A 9-year-old Korean girl presented with typical clinical features of FPS. She had generalized loose skin with decreased subcutaneous fat, skin wrinkling on the forehead and limbs, skull deformities and a peculiar facial appearance with microphthalmia and midface hypoplasia, anomalies of the digits and nails, a large umbilical hernia and a nearly normal developmental outcome. She exhibited prenatal and postnatal growth retardation together with short stature, and records showed that her height and weight were invariably under − 2.0 SD from birth to the age of 10 years. SLC25A24 analysis revealed a heterozygous mutation reported previously, NM_013386:c.650G > A, p.[Arg217His]. After screening her family for the identified mutation, she was confirmed as being a de novo case of FPS caused by an SLC25A24 mutation. Conclusion We describe a Korean girl with typical clinical findings of FPS and a de novo mutation in SLC25A24, as well as 10 years of clinical follow-up, including growth and developmental achievements.This study was supported by grant no. 05–2018-0010 from the SNUH Research Fund. The funder had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript

Optical biochemical sensor based on half-circled microdisk laser diode

In this study, a half-circled cavity based microdisk laser diode is proposed and demonstrated experimentally for an integrated photonic biochemical sensor. Conventional microdisk sensors have limitations in optical coupling and reproducibility. In order to overcome these drawbacks, we design a novel half-circled micro disk laser (HC-MDL) which is easy to manufacture and has optical output directionality. The Q-factor of the fabricated HC-MDL was measured as 7.72 × 106 using the self-heterodyne method and the side mode suppression ratio was measured as 23 dB. Moreover, gas sensing experiments were performed using the HC-MDL sensor. A wavelength shift response of 14.21 pm was obtained for 100 ppb dimethyl methylphosphonate (DMMP) gas and that of 14.70 pm was obtained for 1 ppm ethanol gas. These results indicate the possibility of highly sensitive gas detection at ppb levels using HC-MDL. This attractive feature of the HC-MDL sensor is believed to be very useful for a wide variety of optical biochemical sensor applications. © 2017 Optical Society of America.1