7 research outputs found
Preliminary Results Of A Helicopter Electromagnetic And Magneztic Survey Of The Oak Ridge Reservation, Tiwnessee For Environmental And Geologic Site Characterization
No full textDigital data from the Great Sand Dunes airborne gravity gradient survey, south-central Colorado
No full textFlexible rod design for educational wind balance
No full textThis is a copy of the author 's preprint version of an article published in the journal Experimental techniques. The final publication is available at Springer via http://dx.doi.org/10.1007/s40799-016-0017-9This article provides a technical description of a flexible hinge for wind tunnel rigs. For academic purposes, the device was integrated into several rod flexures to build a home-made external wind balance system. The cylindrical elastic element incorporates several notches, and the flexure linkage is able to transmit force in the main axial direction without hindering perpendicular movement. The flexural element described here is simple and easily manufactured, and can also be used with other types of wind balance. The flexure described in this article has similar functionality to those mentioned in the reference section, but has a more compact element. The project's effectiveness was demonstrated in a series of experimental comparisons of forces and moments measured on a wing using the N.A.C.A. Clark-Y airfoil profile
Flexible rod design for educational wind balance
No full textThis is a copy of the author 's preprint version of an article published in the journal Experimental techniques. The final publication is available at Springer via http://dx.doi.org/10.1007/s40799-016-0017-9This article provides a technical description of a flexible hinge for wind tunnel rigs. For academic purposes, the device was integrated into several rod flexures to build a home-made external wind balance system. The cylindrical elastic element incorporates several notches, and the flexure linkage is able to transmit force in the main axial direction without hindering perpendicular movement. The flexural element described here is simple and easily manufactured, and can also be used with other types of wind balance. The flexure described in this article has similar functionality to those mentioned in the reference section, but has a more compact element. The project's effectiveness was demonstrated in a series of experimental comparisons of forces and moments measured on a wing using the N.A.C.A. Clark-Y airfoil profile.Preprin
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Aerial remote sensing surveys progress report: Helicopter geophysical survey of the Oak Ridge Reservation
No full textThe 35,252 acre Department of Energy Oak Ridge Reservation (ORR) in the western portion of the Appalachian Valley and Ridge Province in Tennessee, has been a nuclear production and development facility for50 years. Contaminants in the many waste sites on the ORR include a wide variety of radioactive isotopes as well as many organic and inorganic compounds. The locations, geometry, and contents of many of these waste sites are reasonably well known, while others are poorly known or unknown. To better characterize the reasonably well known sites and search for additional potentially environmentally hazardous sites, a two-phase aerial survey of the ORR was developed. Phase I began in March 1992 and consisted of aerial radiation, multispectral scanner, and photographic (natural color and color infrared) surveys. Phase II began in November 1992 and is described in this report. Phase II consisted of helicopter electromagnetic (HEM), magnetic, and gamma radiation surveys. Targets of the survey included both man-made (drums, trench boundaries, burn pits, well heads) and geologic (fractures, faults, karst features, geologic contacts) features. The Phase II survey has three components: testing, reconnaissance, and high-resolution data acquisition. To date, the testing and reconnaissance data acquisition have been completed, and some of the data have been processed. They indicate that: (1) magnetic and HEM data are complementary and do not always highlight the same anomaly; (2) under favorable circumstances, helicopter magnetometer systems are capable of detecting groups of four or more 55-gal drums at detector altitudes of 15 m or less; (3) HEM data provide data that compare favorably with surface data collected over burial trenches, (4) well casings may be related to magnetic monopole anomalies, as would be expected; and (5) changes in HEM and magnetic anomaly character are related to lithologic changes and may be used to track contacts between known outcrops
Mercury distribution in different environmental matrices in aquatic systems of abandoned gold mines, western Colombia: Focus on human health
No full textTotal mercury (THg), methylmercury (MeHg) in water, sediments, macrophytes, fish and human health risks were analyzed and assessed from abandoned gold mining ponds (AGMPs)/ mining areas in Western Colombia to know its present environmental condition. Concentrations of THg in water (avg. 13.0 ±13.73ng L-1) was above the EPA threshold level (12ng L-1), suggesting possible chronic effects. Sediment sample revealed that the ponds are methylated (%MeHg: 3.3–11%). Macrophyte Eleocharis elegans presented higher THg content in the underground biomass (0.16 ±0.13µg g-1 dw) than in the aerial biomass (0.05 ±0.04µg g-1 dw) indicating accumulation of THg. MeHg was the most abundant chemical species in fish (MeHg/THg: 83.2–95.0%), signifying higher bioavailability and its risk towards human health. Fish samples (15%) indicate that THg were above WHO limit (0.5µg g), particularly in Ctenolucius beani, Hoplias malabaricus) and lowest in Sternopygus aequilabiatus and Geophagus pellegrini. Bioaccumulation and biomagnification of MeHg were higher in the carnivores representing a source of exposure and potential threat to human health. Fulton’s condition factor (K) for bioaccumulation indicate a decrease with increasing trophic level of fishes. Overall results suggest, mercury species found in different AGMPs compartments should be monitored in this region.The authors wish to thank the Administrative Department of Science, Technology and Innovation - “Francisco José de Caldas” (COLCIENCIAS) grant 694-2014 and 849-2018. MPJ thanks Sistema Nacional de Investigadores, CONACyT and Instituto Politécnico Nacional (EDI and COFAA), México. This article is contributed (partial) from the Earth System Science Group (ESSG), Mexico and Chennai, India (Participating member: MPJ).Peer reviewe
Distribución multicompartimental y fraccionamiento químico del mercurio en pozas de sedimentación de minas de aluvión abandonadas en un área aurífera del departamento del Chocó
No full textEl mercurio (Hg) es uno de los contaminantes ambientales más peligrosos que amenaza la salud de los ecosistemas acuáticos y las poblaciones humanas en muchas regiones del mundo. La minería de oro artesanal y a pequeña escala (ASGM) a menudo libera el Hg (aprox. 1400 Mg/año) principalmente en su forma elemental (Hg0), lo que conduce a la contaminación del suelo y los sistemas acuáticos adyacentes (ríos, lagos, embalses/reservorios). Por ello, pozas de extracción de oro abandonados en los antiguos sitios de minería del oro (AGMP) son particularmente susceptibles a presentar altas concentraciones de Hg en sus compartimentos ambientales. En estos sistemas, los sedimentos actúan como importantes sumideros/fuentes de Hg; pero, algunas variaciones en las condiciones químicas o físicas en ellos (por ejemplo, pH, Eh, OM, textura, Fe, S, Al) provocarán directamente cambios en la distribución, solubilidad, biodisponibilidad y toxicidad de los metales. Por ejemplo, el Hg puede biotransformarse en metilmercurio (MeHg), una poderosa neurotoxina que se bioacumula y biomagnifica en toda la red trófica. Además, se debe resaltar que en muchos países las AGMPs corresponden a lugares de pesca frecuentes para las comunidades locales. En consecuencia, es probable que las AGMPs sirvan de enlace con las poblaciones humanas que dependen directamente del consumo de pescado de las pozas como fuente primaria de proteínas, lo que también podría conducir a efectos negativos crónicos en la salud de los habitantes locales.Mercury (Hg) is one of the most dangerous pollutants that threatens the health of aquatic ecosystems and human populations in many regions around the world. Artisanal and small-scale gold mining (ASGMs) often releases Hg (approx. 1400 Mg/year) primarily in its elemental form (Hg0), which leads to contamination of the soil and adjacent aquatic systems (rivers, lakes, reservoirs/ponds). Therefore, the abandoned gold mining ponds (AGMPs) at the former gold mining sites are particularly susceptible to high concentrations of Hg in their environmental compartments. In these systems, sediments act as important sinks/sources of Hg. However, some variations in the chemical or physical conditions of the sediments (eg., pH, Eh, OM, texture, Fe, S, Al) will directly cause changes in the distribution, solubility, bioavailability and toxicity of the metals. For example, Hg can be biotransformed to methylmercury (MeHg), a powerful neurotoxin that bioaccumulates and biomagnifies throughout the trophic network. Additionally, in many countries, the AGMPs correspond to common fishing sites for local communities. Consequently, the AGMPs is likely to serve as a bond with the human populations who directly depend on the consumption of fish from the ponds as a primary source of protein, and this process also leads to chronic negative effects on the health of the local habitants.Doctor en IngenieríaDoctorad
