The control of maturity and kerogen type on quantitative analytical pyrolysis data

Quantitative pyrolysis-gas chromatography has been performed on 96 kerogen samples isolated from 17 wells on the Norwegian Continental shelf. Petrographic and bulk geochemical measurements were also performed on the samples, and a combined data set of 117 variables for each sample was analysed using principal components analysis (PCA). This approach provides an objective and reproducible means of kerogen characterisation, which can be easily automated. In addition to objective kerogen characterisation and facile visualisation of facies and maturity related chemical trends, the method has the potential to allow objective prediction of key geochemical parameters such as maturity level from pyrogram data.     

Field Comparison of Micropurging vs. Traditional Ground Water Sampling

Micropurge sampling of ground water wells has been suggested as a possible replacement to traditional purge and sample methods. To compare methods, duplicate ground water samples were collected at two field sites using iraditional and micropurge methods. Samples were analyzed for selected organic and inorganic constituents, and the results were compared statistically. Analysis of the data using the nonparametric sign test indicates that within a 95 percent confidence interval, there was no significant difference between the two methods for the site contaminants and the majority of analytes. These analytical results were supported by visual observations with the colloidal borescope, which demonstrated impacts on the flow system in the well when using traditional sampling methods. Under selected circumstances, the results suggest replacing traditional sampling with micropurging based on reliability, cost, and waste minimization.     

Measurements of upper and lower tidal currents at Banc de la Chapelle

Summary Measuring and analysis techniques are described for two sets of measurements of tidal currents near the surface and near the bottom at Banc de la Chapelle, a location 165 m. deep above the edge of the West European Continental Shelf. Reliable results are obtained for the semi-diurnal currents, but the scatter of the data is too great for consistent results to be extracted for the small diurnal and quarter-diurnal tidal constituents. The major axes of the mean semidiurnal current ellipses are aligned at about 30°. This direction is normal to the line of greatest slope of the shelf edge and to the main alignment of the large sand waves on the bank, which accords with a theory of formation of the latter. Bottom currents are on the average about 69% of the surface currents in magnitude. There is also some evidence for a residual drift of about 0·2 knot towards the West. An analysis is made of the errors involved in estimating the drift of a ship from Radar sights on moored buoys.

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Messungen der oberen und unteren Gezeitenströmungen bei der La-Chapelle-Bank

Zusammenfassung Es werden Meß- und Analysemethoden beschrieben für zwei Serien von Gezeitenstrommessungen nahe der Oberfläche und in Bodennähe auf der La-Chapelle-Bank, einer 165 m tiefen Stelle am Rand des West-Europäischen Kontinentalabhangs. Für halbtägige Gezeitenströme wurden zuverlässige Ergebnisse erzielt, die Streuung der Werte ist jedoch zu groß, um übereinstimmende Ergebnisse für die kleinen ganztägigen und vierteltägigen Tiden aus ihnen ableiten zu können. Die Hauptachsen der mittleren halbtägigen Gezeitenstrom-Ellipse bilden einen Winkel von rechtweisend 30⁰. Diese Richtung verläuft senkrecht zur Linie der größten Neigung des Schelfrandes und zur Hauptrichtung der großen Sandwellen auf der Bank, was mit der Theorie über die Entstehung der Bank übereinstimmt. Die Bodenströmungen betragen ungefähr 69% der Oberflächenströmungen. Es scheint auch ein Reststrom von ungefähr 0,2 kn in westlicher Richtung vorhanden zu sein. Die Fehler, die bei Errechnung der Abdrift eines Schiffes mit Hilfe von Radar-Beobachtungen von einer verankerten Boje aus auftreten, werden untersucht.

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La mesure des courants supérieurs et inférieurs de marée sur la banque de la Chapelle

Résumé On décrit des méthodes de mesure et d'analyse pour deux séries de mesures des marées près de la surface et au voisinage du fond sur la banque de la Chapelle, un endroit situé à 165 m de profondeur au bord de la marge continentale de l'Europe occidentale. Des résultats authentiques ont été obtenus en ce qui concerne les marées semi-diurnes, leurs valeurs, cependant, diffèrent à un tel point que l'on ne peut en dériver des résultats conformes pour les petites marées quart-diurnes ou pour celles qui se produisent seulement une fois par jour. Les axes principaux de l'ellipse de la marée semi-diurne forment un angle vrai de 30 degrés. Cette direction suit un cours perpendiculaire à la ligne de la plus grande pente de la marge continentale et à la direction principale de grandes rides de sable sur la banque ce qui s'accorde bien avec la théorie de sa genèse. Les courants au voisinage du fond font 69% des courants superficiels. En outre, il paraît qu'il existe un courant résiduel orienté vers l'ouest dont la vitesse est de 0,2 noeud. Les erreurs se produisant lorsqu'on calcule la dérive du bâtiment à l'aide des observations de radar faites à bord d'une bouée ancrée sont étudiées.

     

Acoustic-Gravity Wave Propagation in a Measured Atmosphere

Summary An atmosphere is modelled by averaging measurements taken at eight locations for 1968 September 9. The effectiveness of the modelling is evaluated by comparing the atmospheric dispersion properties determined from an experimentally recorded signal resulting from a nuclear explosion on that date and those computed from the model atmosphere. The effects of atmospheric winds are shown to change the dispersion properties.
A theoretical barogram is synthesized for a receiver located 7930 km from the source and is compared to the recorded signal for the event. Barograms are synthesized for two different source functions and the source functions are discussed.     

INTEGRATION OF THE MODELS OF ANNAGNPS AND REMM TO ASSESS RIPARIAN BUFFER SYSTEM FOR SEDIMENT REDUCTION

The United States Department of Agriculture (USDA) Annualized Agricultural Non-Point Source Pollution model (AnnAGNPS) is used to help evaluate a watershed response to agricultural management practices to control water quality. However, AnnAGNPS version 3.5 does not contain features to estimate the effect of a riparian buffer (RB) system on water quality. The Riparian Ecosystem Management Model (REMM) is used to simulate the impact of riparian buffer systems on water quality. However, frequently the lack of measured upland loadings that are required by REMM simulation limits the application of REMM. To address this data gap, a study was conducted to integrate AnnAGNPS with REMM for RB system simulation. AnnAGNPS was used to simulate water and sediment loadings from an upland field into a three-zone RB system at the Gibbs Farm located in the Georgia coastal plain. These AnnAGNPS outputs were used as the inputs to REMM. REMM was used to simulate water and sediment movement along the riparian buffers. The AnnAGNPS simulated amount of annual runoff at the edge of the field was close to observed amounts (Nash-Sutcliffe efficiency of 0.92). It is believed that a substantial portion of sand was removed from the runoff one meter into the grass buffer where the samplers were located; therefore, sand was excluded from the AnnAGNPS simulation for comparison with observed sediment. Excluding sand, the AnnAGNPS predicted amount of annual sediment matches the observed amount fairly well (Nash-Sutcliffe efficiency of 0.46). In addition, based on evaluating the percent reduction of sediment at each zonal interface, the AnnAGNPS/REMM model well simulated the function of the RB system to reduce sediment.     

Extension of a polar ionospheric current to the nightside equator

A detailed analysis of rapid-run magnetograms from Guam (geomagnetic latitude = 4.2°) revealed that there are two kinds of geomagnetic sudden commencement (SC) observed in nighttime. One is the ordinary SC consisting of a main impulse only which has a smooth rise of the H-component. The other is a superposition by a small positive impulse on the very beginning part of the smooth rise of the main impulse and consequently the SC starts with a small stepwise increase of the H-component. The latter type of SC occurs between 20 and 08 h L.T. and its occurrence rate takes the maximum value of about 50% around 03 h L.T. Corresponding magnetograms from a dayside equatorial station (Huancayo, geomagnetic latitude = ?0.7°) were examined and a good correlation was found between the stepwise SC at the nightside (Guam) and SC¹ with a preliminary reverse impulse (PRI) at the dayside (Huancayo). Since PRI observed at the dayside equator may be interpreted as an extension of an ionospheric current due to an dusk-to-dawn electric field impressed on the polar ionosphere, our results show that a polar originating ionospheric current can extend to the nightside equator and produce a small but observable magnetic effect in spite of much reduced nighttime ionospheric conductivity.     

A minimal dynamical model for tidal synchronization and orbit circularization

We study tidal synchronization and orbit circularization in a minimal model that takes into account only the essential ingredients of tidal deformation and dissipation in the secondary body. In previous work we introduced the model (Escribano et al. in Phys. Rev. E, 78:036216, 2008); here we investigate in depth the complex dynamics that can arise from this simplest model of tidal synchronization and orbit circularization. We model an extended secondary body of mass m by two point masses of mass m/2 connected with a damped spring. This composite body moves in the gravitational field of a primary of mass M ≫ m located at the origin. In this simplest case oscillation and rotation of the secondary are assumed to take place in the plane of the Keplerian orbit. The gravitational interactions of both point masses with the primary are taken into account, but that between the point masses is neglected. We perform a Taylor expansion on the exact equations of motion to isolate and identify the different effects of tidal interactions. We compare both sets of equations and study the applicability of the approximations, in the presence of chaos. We introduce the resonance function as a resource to identify resonant states. The approximate equations of motion can account for both synchronization into the 1:1 spin-orbit resonance and the circularization of the orbit as the only true asymptotic attractors, together with the existence of relatively long-lived metastable orbits with the secondary in p:q (p and q being co-prime integers) synchronous rotation.     

In Situ Maintenance of Traditional Ecological Knowledge on Malekula Island,Vanuatu

Traditional ecological knowledge (TEK) guides resource management across the globe, but is at risk amid social and ecological change. This has prompted numerous calls for TEK maintenance efforts, but these remain largely unexamined in the literature. Here, we discuss three examples of in situ TEK maintenance from Malekula Island in Vanuatu, locally known as kastom schools. Based on qualitative data, we find that the kastom schools may create several opportunities to maintain TEK (e.g., establishing local control over education), and argue that they represent the creative and adaptive management of tradition in dynamic social–ecological contexts. However, a number of challenges, both practical (e.g., lack of funding) and epistemological (e.g., changing modes of cultural transmission), threaten the efficacy of the kastom schools. We argue that in situ modes of TEK maintenance have promise, but that issues of power and heterogeneity require serious consideration if such measures are to succeed.