Kinematic study of planetary nebulae in NGC 6822

By measuring precise radial velocities of planetary nebulae (which belong to the intermediate age population), H II regions, and A-type supergiant stars (which are members of the young population) in NGC 6822, we aim to determine if both types of population share the kinematics of the disk of H I found in this galaxy. Spectroscopic data for four planetary nebulae were obtained with the high spectral resolution spectrograph Magellan Inamori Kyocera Echelle (MIKE) on the Magellan telescope at Las Campanas Observatory. Data for other three PNe and one H II region were obtained from the SPM Catalog of Extragalactic Planetary Nebulae which employed the Manchester Echelle Spectrometer attached to the 2.1m telescope at the Observatorio Astron\'omico Nacional, M\'exico. In the wavelength calibrated spectra, the heliocentric radial velocities were measured with a precision better than 5-6 km s$^{-1}$. Data for three additional H II regions and a couple of A-type supergiant stars were collected from the literature. The heliocentric radial velocities of the different objects were compared to the velocities of the H i disk at the same position. From the analysis of radial velocities it is found that H II regions and A-type supergiants do share the kinematics of the H I disk at the same position, as expected for these young objects. On the contrary, planetary nebula velocities differ significantly from that of the H I at the same position. The kinematics of planetary nebulae is independent from the young population kinematics and it is closer to the behavior shown by carbon stars, which are intermediate-age members of the stellar spheroid existing in this galaxy. Our results are confirming that there are at least two very different kinematical systems in NGC 6822

Combining dimensional analysis with model based systems engineering

The model based systems engineering (MBSE) approach describes a system using consistent views to provide a holistic model as complete as possible. MBSE methodologies end with the physical architecture of the system, but a physical model is clearly incomplete without the study of its associated physical laws and phenomena related to the whole system or its parts. However, the computational demands could be excessive even for modest projects. Dimensional analysis (DA) is common in fluid dynamics and chemical engineering, but its application to systems engineering is still limited. We describe an engineering methodological process, which incorporates DA as a powerful tool to understand the physical constraints of the system without the burden of complex analytical or numerical calculations. A detailed example describing a microantenna is presented showing the benefits of this approach. The selected example describes a problem rarely covered in modern expositions of DA in order to show the wide benefit of these techniques. The information provided by this analysis is very useful to select the best physically realizable architectures, testing design, and conduct trade-off studies. The complexity of modern systems and systems of systems demands new testing procedures in order to comply with increasingly demanding requirements and regulations. This can be accomplished through research in new DA methods. Finally, this article serves as a fairly comprehensive guide to the use of DA in the context of MBSE, detailing its strengths, limitations, and controversial issues

Design of a flow deflector for an accurate flow meter calibration facility

The design and test of a flow deflector gate used for controlling the flow deviation toward the primary tank in a flow-meter calibration facility is presented. The deflector gate is pneumatically controlled and permits the flow conduction to either the suction tank or to the primary tank. The deflector is designed to approximately compensate the flow deficit towards the primary tank during the opening, with the flow excess while in the shutting process. Numerical simulations are performed to study the flow hydrodynamics during the deflector operation. Results are compared to experimental data, and used to improve the gate design. The enhanced design proved to guarantee the uniformity of the flow through the calibration section and the dramatic reduction of the error in volume measurement during calibration

Design of a large scale flow-meter test and calibration facility

The design and set up of a large-scale flowmeter calibration and test facility is presented. The facility was designed to handle flowmeters with diameters between 6” and 14”, flow rates up to 0.3 m3/s and to give results less than 1% accurate. The calibration methodology consisted firstly in calibrating the pattern flowmeters, using volume and time primary measurements, and secondly, comparing the pattern to the flowmeters needing calibration. The design and calculation of the primary calibration device is addressed, including numerical simulations of the outflow manifold and the comparison to experimental data. The calibration facility proved to be accurate and reliable in producing renewed calibration data for various tested flowmeter

Design of a large scale flow-meter test and calibration facility

The design and set up of a large-scale flowmeter calibration and test facility is presented. The facility was designed to handle flowmeters with diameters between 6” and 14”, flow rates up to 0.3 m3/s and to give results less than 1% accurate. The calibration methodology consisted firstly in calibrating the pattern flowmeters, using volume and time primary measurements, and secondly, comparing the pattern to the flowmeters needing calibration. The design and calculation of the primary calibration device is addressed, including numerical simulations of the outflow manifold and the comparison to experimental data. The calibration facility proved to be accurate and reliable in producing renewed calibration data for various tested flowmeter

Design of the distribution manifold for a large-scale flowmeter calibration facility

The design and test of the distribution manifold for a large-scale flowmeter calibration facility is presented. The design was intended to have an air-free flow operation and a free-surface flow-like towards the downstream half-body discharge. Back of the envelope calculations are presented for the estimation of the preliminary dimensions. Numerical simulations of the flow during manifold steady state operation are utilized to refine the manifold design. No air entrapment is noticed in the flow simulatio

Bochdalek hernia associated with intestinal malrotation as an incidental finding in an adult patient: case report

Bochdalek hernia (BH) is the most common congenital diaphragmatic hernia, however in adults the clinical presentation and diagnosis is rare. Intestinal malrotation (IM) is a congenital anomaly that results in an alteration in intestinal anatomy secondary to inadequate intestinal rotation, which occurs at the end of the first trimester of embryonic development, some digestive anomalies may be related, such as diaphragmatic hernia, its Diagnosis is made in the neonatal period although it can be diagnosed in older children and adults, debuting with symptoms of intestinal obstruction or being an incidental finding. Below we present a case report of an adult patient with a diagnosis of Bochdalek congenital diaphragmatic hernia (CDH) in whom an incidental diagnosis of IM was made, who underwent elective surgery, performing laparoscopic diaphragmatic plasty with favorable results