Development and Prototype Validation of an Additive Manufactured Cubesat Propulsion Tank

The purpose of this study is to determine if a cubesat propellant tank using the additive manufacturing technology of direct metal laser sintering meets the requirements, and material properties of a conventionally manufactured tank. Additionally, to see if additive manufactured parts are a viable option to be used in cubesat applications. This was accomplished by designing a model which will be used by the ARAPAIMA cubesat that meets all the Air Force\u27s University Nanosatellite Program (UNP), NASA\u27s and Department of Defense\u27s requirements for pressurized vessels and material properties. A finite element analysis study was conducted to determine where and when the propulsion tank will fail using an isotropic material. Afterwards two propulsion tanks were manufactured, one for nondestructive evaluation and inspection and the other for destructive testing. The task for destructive testing was prepared for hydrostatic pressure test, by plugging the holes for external components and by, installing six strain gages. The purpose of this test has been to compare the material properties of the isotropic FEA model of the tank to the anisotropic 3D printed tank. After testing the propulsion tank to failure in the hydrostatic pressure chamber, is it clear that the AlSi10Mg material is stronger than a billet Aluminum 6061 T-6. The maximum operating pressure of the propulsion tank is 160 psi and the pressure the tank ruptured is 410 psi proves that FEA correctly predicted a factor of safety of 2.10. The results also proved that the propulsion tank was over designed and needs to be optimized to reduce weight and be redesigned for additive manufacturing in mind, such as an internal lattice support structure. Some features are still included to ease the labor if manufactured by conventional means

Pinworms of the red howler monkey (Alouatta seniculus) in Colombia. Gathering the pieces of the pinworm-primate puzzle

Pinworms of primates are believed to be highly host specific parasites, forming co-evolutionary associations with their hosts. In order to assess the strength and reach of such evolutionary links, we need to have a broad understanding of the pinworm diversity associated with primates. Here, we employed an integrative taxonomic approach to assess pinworm diversity in red howler monkeys in Colombia. Molecular and morphological evidence validate the presence of at least four different species of Trypanoxyuris occurring in red howler monkeys: T. minutus, a widely distributed species, and three new species, T. seunimiii n. sp., T. kemuimae n. sp. and T. kotudoi n. sp. The mitochondrial COI gene and the 28S ribosomal gene were used for phylogenetic assessments through Bayesian inference. The three new species were morphologically distinct and formed reciprocally monophyletic lineages. Further molecular lineage subdivision in T. minutus and T. kotudoi n. sp. without morphological correspondence, suggests the potential scenario for the existence of cryptic species. Phylogenetic relationships imply that the different species of Trypanoxyuris occurring in each howler monkey species were acquired through independent colonization events. On-going efforts to uncover pinworm diversity will allow us to test the degree of host specificity and the co-phylogenetic hypothesis, as well as to further unravel the primate-pinworm evolutionary history puzzle

Selection and validation of a turbulence model for the numerical simulation of the flow at hemodialysis cannulas

In recent years, CFD has become an increasingly used tool in the design of blood-based devices. Particularly, the estimation of red blood cell damage (hemolysis) becomes an important challenge to CFD scientists since the blood is a complex fluid present in turbulent regime in most pumping devices. Moreover, previous CFD studies on blood hemolysis lack of reliable relationships between hydraulic results and hematological responses. The objective of this work is to foresee a methodology for performing realistic CFD simulations that lead to reliable hydraulic and hematological correspondence. Cannulae geometries were studied to numerically assess a relatively simple flow with documented hematological data. For the turbulence modeling, a direct numerical simulation (DNS) for a coaxial jet array was used as a benchmark for the selection of an appropriate turbulence model, since the Cannulae approximates the coaxial jet features. Velocity and stress time-averaged profiles were compared between DNS results and the turbulence models. These results, pointed to the Shear Stress Transport with Gamma Theta correlation for transition model as the optimum turbulence model in that geometry. Accurate and reliable hydrodynamic CFD results were obtained for the Cannulae as a previous step to further hematological calculations with a minimum degree of uncertaint

3D CFD Modeling Investigation of Potential Vortex Formation at the Intakes of Caruachi Powerhouse

In this paper, the 3-D CFD simulation of the free-surface flow approaching the intakes of Caruachi Powerhouse is presented. The aim of the investigation is to determine whether or not vortex structures are likely to appear from the water surface through the intakes, as the result of the presence of cofferdams placed few meters upstream of the intakes. The presence of cofferdams was a note of concern with regard to the effects they might have on the turbine intakes once the hydroelectric central starts operating. In all the considered conditions, results did not show neither strong surface vortices in the proximities of the Power House intakes, nor air entrainment-entrapment towards the intakes, which reflects the safe operation of the turbines in the presence of the cofferdams. The latter added in decision taking on leaving the cofferdams submerged instead of removing them, which resulted in cost savings for the projec

CFD study of an oil catch can

Oil catch cans are devices used in some internal combustion engines to prevent oil droplets from entering into the exhaust manifold of the engine. The main purpose of this paper is to study the design of a typical oil catch can used in regular vehicles and analyze the effects caused by varying the length of its inner tube and the relative position of the outlet: either radial or tangential to the can body

3D CFD Modeling Investigation of Potential Vortex Formation at the Intakes of Caruachi Powerhouse

In this paper, the 3-D CFD simulation of the free-surface flow approaching the intakes of Caruachi Powerhouse is presented. The aim of the investigation is to determine whether or not vortex structures are likely to appear from the water surface through the intakes, as the result of the presence of cofferdams placed few meters upstream of the intakes. The presence of cofferdams was a note of concern with regard to the effects they might have on the turbine intakes once the hydroelectric central starts operating. In all the considered conditions, results did not show neither strong surface vortices in the proximities of the Power House intakes, nor air entrainment-entrapment towards the intakes, which reflects the safe operation of the turbines in the presence of the cofferdams. The latter added in decision taking on leaving the cofferdams submerged instead of removing them, which resulted in cost savings for the projec

Numerical simulation of the flow through an intermittent gas lift valve

The numerical simulation of the flow through a pilot valve used in the oil intermittent gas lift process is presented.The complexity of the non-isothermal compressible flow is modeled by the solution of the Navier-Stokes, Mass Conservation and Energy equations for the compressible flow. Numerical results and analyses pertaining to the flow dynamics through a 1½-inch pilot valve at an operating condition encountered in typical field operations are presente

Analysis of pollutant dispersion in a street canyon of Astana

Due to the steadily rising number of vehicles, atmospheric air pollution has become one of the evident problems in main cities around the world. Astana, the capital city of Kazakhstan, is not an exception with it current expansion and economic growth. In order to avoid the hazardous consequences of automobile and industry pollution onto the residents' health of Astana, it is important to analyze and monitor the conditions of atmospheric air in the city. The main objective of this research project is to simulate and analyze the dispersion of vehicle pollutants (CO) at the crossroad of Zhenis and Bogenbay streets using Computational Fluid Dynamics (CFD) tools based on SolidWorks-EFD numerical platform. This particular place for the study is selected because of its relatively heavy traffic load and its close location to many residential buildings

Using Wavelets to reject background in Dark Matter experiments

A method based on wavelet techniques has been developed and applied to background rejection in the data of the IGEX dark matter experiment. The method is presented and described in some detail to show how it efficiently rejects events coming from noise and microphonism through a mathematical inspection of their recorded pulse shape. The result of the application of the method to the last data of IGEX is presented.Comment: 14 pages, 8 figures. Submitted to Astrop. Phy