Organic chemical signatures of New Zealand carbonate concretions and calcite fracture fills as potential fluid migration indicators

Macroscopic calcite crystals are common in sedimenta¬ry strata, occurring both as tectonic veins and also filling one or more generations of septarian rupture or later brittle fractures in calcareous concretions. Traces of hydrocarbons are frequently present in calcite crystals, especially near active petroleum systems, and are routinely the object of fluid inclusion studies linking source and migration pathway. Such calcites are shown here also to contain fatty acids in widely varying amounts ranging from 0.2 to more than 5 μg/g. Vein calcites examined are typically near the lower figure, close to analytical blank levels, and this is also true of some concretionary fracture fill calcites, notably those from the Palaeocene Moeraki ‘boulders’. Other concretionary fracture fill calcites (Jurassic, Scotland; Eocene, Waikato Coal Measures and associated marine strata) have much higher fatty acid contents, especially those filling later brittle style fractures. Although usually less abundant than the fatty acids in the concretions themselves, they lack the long chain n-acids derived from terrestrial vegetation and are commonly dominated by dioic acids. Exceptionally, in the calcitic septarian fill of a sideritic Coal Measures concretion, their abundance far exceeds that of concretion body fatty acids. They appear to be fluid transported, probably in aqueous solution, and have molecular signatures potentially distinctive of maturing organic matter sources from which the fluids derived

Assessment of In-situ Corrosion Conditions at Nevada Mechanically Stabilized Earth Wall Sites: Using Electrochemical Soil Characteristics and Linear Polarization Resistance

The inability of soil to provide sufficient tensile strength presents challenges for soils being used as a structural building material. However, it is possible to improve the structural performance with the inclusion of a reinforcing system. The development of these systems has been a major advancement of the civil engineering practice. Mechanically stabilized earth (MSE) wall systems typically consist of a: concrete facing panel, specified backfill, reinforcing elements, and the retained fill. The interaction of the backfill with the reinforcements, and the reinforcements with the facing panels, produces a system that when properly designed, can be a cost effective engineering solution. In Nevada there are over 150 MSE walls that have been constructed using metallic reinforcements (Thornley 2009). Corrosion of metallic elements a naturally occurring electrochemical process is irreversible an inevitable. The rate of metal loss (corrosion) is a function of the environmental conditions and metal type. For MSE walls key parameters include the backfill’s: salt content, organic content, saturation level, as well as the metal type of the reinforcements.Nevada has two previous corrosion investigations, an extensive site investigation at I-515/ Flamingo Rd. and a statistical analysis of as-built soil records along with a preliminary investigation for I-15/ Cheyenne Blvd. These studies form the foundation for this investigation of in-situ corrosion conditions. Seven MSE wall sites were investigated using electrochemical backfill characterization and linear polarization resistance (LPR) corrosion rate monitoring. Evaluation of electrochemical backfill characteristics has resulted in the discovery of six sites that fail current NDOT/ AASHTO MSE wall backfill requirements. The in-situ soil samples collected and analyzed more than doubled the available data used to describe the corrosiveness of the backfill. Linear polarization resistance corrosion rates were obtained for more than 200 different elements. These data suggest that despite the aggressive nature of the backfill, most elements are preforming well and are below the anticipated rates. However, several elements were discovered with corrosion rates in excess of five times the design model. The use of the LPR corrosion monitoring has concluded that the conditions at I-15/ and Cheyenne Blvd. are equivalent to or worse than the conditions evaluated in 2004 at the I-515/ Flamingo Rd. complex. The discoveries at Flamingo Rd. led to remediation of the largest wall at the complex. Through the use of electrochemical backfill characteristics and LPR corrosion rates, the seven sites investigated have been ranked. The rankings are dependent on several factors such as backfill electrochemical conditions and comparison of corrosion rates data with design models. This study has confirmed that observations of conditions along the exterior of the wall are not sufficient when determining the condition of the soil reinforcements. Routine corrosion monitoring is required to monitor the depletion of the soil reinforcements and should be incorporated into a Long-term Corrosion Monitoring and Asset Management Plan (LCMAMP). It is anticipated that a program will be integrated into Nevada’s current asset management systems. The development and implementation of LCMAMP, directly reflects the federal initiative for systematic detailed evaluation of critical assets, MAP-21

The Future of the Basic Course

This article recommends some changes that should occur in the basic course. The prescriptions are based on four notions: the course must include accurate information; it should be inclusive in nature; it must be responsive to our contemporary world and to our students\u27 current and future communicative needs; and it must provide a unique contribution to our students\u27 education. The authors suggest that the course has not been sufficiently attentive to accuracy, inclusiveness, responsiveness and uniqueness; furthermore, contemporary changes require increased vigilance in these areas

Tubular carbonate concretions as hydrocarbon migration pathways? Examples from North Island, New Zealand

Cold seep carbonate deposits are associated with the development on the sea floor of distinctive chemosyn¬thetic animal communities and carbonate minerali¬sation as a consequence of microbially mediated anaerobic oxidation of methane. Several possible sources of the methane exist, identifiable from the carbon isotope values of the carbonate precipitates. In the modern, seep carbonates can occur on the sea floor above petroleum reservoirs where an important origin can be from ascending thermogenic hydrocar¬bons. The character of geological structures marking the ascent pathways from deep in the subsurface to shallow subsurface levels are poorly understood, but one such structure resulting from focused fluid flow may be tubular carbonate concretions. Several mudrock-dominated Cenozoic (especially Miocene) sedimentary formations in the North Island of New Zealand include carbonate concretions having a wide range of tubular morphologies. The concretions are typically oriented at high angles to bedding, and often have a central conduit that is either empty or filled with late stage cements. Stable isotope analyses (δ13C, δ18O) suggest that the carbonate cements in the concretions precipitated mainly from ascending methane, likely sourced from a mixture of deep thermogenic and shallow biogenic sources. A clear link between the tubular concretions and overlying paleo-sea floor seep-carbonate deposits exists at some sites. We suggest that the tubular carbonate concretions mark the subsurface plumbing network of cold seep systems. When exposed and accessible in outcrop, they afford an opportunity to investigate the geochemical evolution of cold seeps, and possibly also the nature of linkages between subsurface and surface portions of such a system. Seep field development has implications for the characterisation of fluid flow in sedimentary basins, for the global carbon cycle, for exerting a biogeochemical influence on the development of marine communities, and for the evaluation of future hydrocarbon resources, recovery, and drilling and production hazards. These matters remain to be fully assessed within a petroleum systems framework for New Zealand’s Cenozoic sedimentary basins

Prospectus, April 16, 1997

https://spark.parkland.edu/prospectus_1997/1012/thumbnail.jp

Magnetically warped discs in close binaries

We demonstrate that measurable vertical structure can be excited in the accretion disc of a close binary system by a dipolar magnetic field centred on the secondary star. We present the first high resolution hydrodynamic simulations to show the initial development of a uniform warp in a tidally truncated accretion disc. The warp precesses retrogradely with respect to the inertial frame. The amplitude depends on the phase of the warp with respect to the binary frame. A warped disc is the best available explanation for negative superhumps.Comment: 11 pages, 10 figures, MNRAS accepte

Furthering the Growth of Cloud Computing by Providing Privacy as a Service

The evolution of Cloud Computing as a viable business solution for providing hardware and software has created many security concerns. Among these security concerns, privacy is often overlooked. If Cloud Computing is to continue its growth, this privacy concern will need to be addressed. In this work we discuss the current growth of Cloud Computing and the impact the public sector and privacy can have in furthering this growth. To begin to provide privacy protection for Cloud Computing, we introduce privacy constraints that outline privacy preferences. We propose the expansion of Cloud Service Level Agreements (SLAs) to include these privacy constraints as Quality of Service (QoS) levels. This privacy QoS must be agreed upon along with the rest of the QoS terms within the SLA by the Cloud consumer and provider. Finally, we introduce Privacy as a Service (PraaS) to monitor the agreement and provide enforcement if necessary

Hearing Care and Management Priority Among Parents of Children with Down Syndrome: A Grounded Theory

Objective: This study qualitatively explored the factors that influence how parents of children who are Deaf or hard-of-hearing with Down syndrome prioritize hearing care and management and developed an associated theory to explain that priority. Design: Grounded theory was used for the purposes of this qualitative study. Data were collected using in-depth interviews which were analyzed using a three-tiered qualitative coding process. Study Sample: Eighteen mothers of children who are Deaf or hard-of-hearing with Down syndrome participated in this study. Results: The higher the extent of engaged professional support, perception of benefit for child, parent activation, and family engagement, the higher the priority for hearing care and management will likely be among parents of children who are Deaf or hard-of-hearing with Down syndrome. Conclusions: Understanding how parents of children who are Deaf or hard-of-hearing with Down syndrome decide to prioritize hearing care and management has implications for how hearing health providers and others provide care to parents to enhance priority for hearing-related needs

Habitual physical activity and cardiometabolic risk factors in adults with cerebral palsy

2014 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license(http://creativecommons.org/licenses/by/3.0/).This article has been made available through the Brunel Open Access Publishing Fund.Adults with cerebral palsy (CP) are known to participate in reduced levels of total physical activity. There is no information available however, regarding levels of moderate-to-vigorous physical activity (MVPA) in this population. Reduced participation in MVPA is associated with several cardiometabolic risk factors. The purpose of this study was firstly to compare levels of sedentary, light, MVPA and total activity in adults with CP to adults without CP. Secondly, the objective was to investigate the association between physical activity components, sedentary behavior and cardiometabolic risk factors in adults with CP. Adults with CP (n = 41) age 18–62 yr (mean ± SD = 36.5 ± 12.5 yr), classified in Gross Motor Function Classification System level I (n = 13), II (n = 18) and III (n = 10) participated in this study. Physical activity was measured by accelerometry in adults with CP and in age- and sex-matched adults without CP over 7 days. Anthropometric indicators of obesity, blood pressure and several biomarkers of cardiometabolic disease were also measured in adults with CP. Adults with CP spent less time in light, moderate, vigorous and total activity, and more time in sedentary activity than adults without CP (p < 0.01 for all). Moderate physical activity was associated with waist-height ratio when adjusted for age and sex (β = −0.314, p < 0.05). When further adjustment was made for total activity, moderate activity was associated with waist-height ratio (β = −0.538, p < 0.05), waist circumference (β = −0.518, p < 0.05), systolic blood pressure (β = −0.592, p < 0.05) and diastolic blood pressure (β = −0.636, p < 0.05). Sedentary activity was not associated with any risk factor. The findings provide evidence that relatively young adults with CP participate in reduced levels of MVPA and spend increased time in sedentary behavior, potentially increasing their risk of developing cardiometabolic disease