JHomogenizer: a computational tool for upscaling permeability for flow in heterogeneous porous media

This paper presents an object-oriented programming approach for the design of numerical homogenization programs, called JHomogenizer. It currently includes five functional modules to compute effective permeability and simple codes for computing solutions for flow in porous media. Examples with graphical output are shown to illustrate some functionalities of the program. A series of numerical examples demonstrates the effectiveness of the methodology for two-phase flow in heterogeneous reservoirs. The software is freely available, and the open architecture of the program facilitates further development and can adapt to suit specific needs easily and quickly.     

Toxicity comparison of biosurfactants and synthetic surfactants used in oil spill remediation to two estuarine species

The relative environmental toxicities of synthetic and biogenic surfactants used in oil spill remediation efforts are not well understood. Acute and chronic toxicities of three synthetic surfactants and three microbiologically produced surfactants were determined and compared in this study for the estuarine epibenthic invertebrate, Mysidopsis bahia and the inland silverside, Menidia beryllina. The toxicities of the surfactant were determined in standard laboratory static and static-renewal tests of 4-7 d duration. Results were specific to the surfactant, response parameter and test species. The LC50 values (nominal concentrations) for M. bahia ranged from 3.3 mg/l (Triton X-100) to >1000 mg/l (PES-61) and 2.5 mg/l (Triton X-100) to 413.6 mg/l (PES-61) for M. beryllina. Chronic first-effect concentrations (mg/l) for the six surfactants ranged from 2.3 to 465.0 (M. beryllina) and 1.0 to >1000.0 (M. bahia) based on reductions in growth and fecundity. Few generalizations could be made concerning the results due to their variability but M. bahia was generally the more sensitive species and the toxicities of the biosurfactants were intermediate to those of the synthetic surfactants.     

Crew variability in topographic surveys for monitoring wadeable streams: a case study from the Columbia River Basin

Digital elevation models (DEMs) derived from ground‐based topographic surveys have become ubiquitous in the field of fluvial geomorphology. Their wide application in spatially explicit analysis includes hydraulic modeling, habitat modeling, and morphological sediment budgeting. However, there is a lack of understanding regarding the repeatability and precision of DEMs derived from ground‐based surveys conducted by different, and inherently subjective, observers. This is of particular concern when we consider the proportion of studies and monitoring programs that are implemented across multiple sites and over time by different observers. We used a case study from the Columbia Habitat Monitoring Program (CHaMP), where seven field crews sampled the same six sites, to quantify the magnitude and effect of observer variability on DEMs interpolated from total station surveys. We quantified the degree to which DEM‐derived metrics and measured geomorphic change were repeatable. Across all six sites, we found an average elevation standard deviation of 0.05 m among surveys, and a mean total range of 0.16 m. A variance partition between site, crew, and unexplained errors for several topographically derived metrics showed that crew variability never accounted for > 1.5% of the total variability. We calculated minor geomorphic changes at one site following a relatively dry flow year between 2012 and 2011. Calculated changes were minimal (unthresholded net changes ±1–3 cm) with six crews detecting an indeterminate sediment budget and one crew detecting a minor net erosional sediment budget. While crew variability does influence the quality of topographic surveys, this study highlights that when consistent surveying methods are employed, the data sets are still sufficient to support derivation of topographic metrics and conduct basic geomorphic change detection. Copyright © 2014 John Wiley & Sons, Ltd.     

Dissolved Pb Concentrations and Stable Pb Isotope Ratios in the Ulleung Basin,East/Japan Sea

Ocean Science Journal - The spatial distributions of dissolved lead (Pb) concentrations and stable Pb isotope ratios in the Ulleung Basin, East/Japan Sea, were investigated to identify the Pb...     

Interactions of Mesoscale Eddy and Western Boundary Current: A Reduced-Gravity Numerical Model Study

A reduced-gravity primitive equation eddy resolving model is used to study the interaction of a typhoon-induced eddy and a wind-driven general circulation. A typhoon-induced eddy is characterized by a core with a relative vorticity of the same order as the local Coriolis parameter. This eddy is neutrally stable relative to a disturbance induced by the westward advection of the eddy, due to the planetary β-effect. Hence, its evolution in the open ocean is similar to the classical frontal geostrophic eddy. Within the western boundary flow regime, the eddy is entrained northward by the mean circulation. This northward eddy advection and the mean-vorticity advection due to eddy flow induce another disturbance with a north-south asymmetry into the circular eddy. Together with the zonal asymmetric disturbance, associated with the planetary β-effect, the original circular eddy becomes unstable. The nonlinear eddy-flow interactions in the eastern flank of a western boundary current causes the eddy to deform quickly into an ellipse and lose its waters and energy into the mean circulation.     

An emendation of elastic rebound theory: Main rupture and adjacent belt of right-lateral distortion detected by Viaduct at Kaynaşli, Turkey 12 November 1999 Düzce Earthquake

The fault trace of the 12 November 1999 earthquake in theDüzce-Bolu region in Anatolia crossed the alignment of a 2.4 kmviaduct in Kaynali that had been carefully surveyed. The builders of theviaduct, the ASTALDI-BAYINDIR Co., resurveyed the viaduct after theearthquake. We repeated the survey for approximately one kilometre of theeastern end of the viaduct and obtained essentially identical results. Thoughit was unfortunate that the earthquake damaged the new structure, the piersdid produce a very rare record of ground deformation of an earthquake.In effect, the viaduct was a giant strain gage that yielded reliable data aboutground movement and distortion near a fault. This paper describes thesurvey data and their evaluation leading to convincing evidence that (a) thefault trace must be considered, not as a fault line or plane, but as a faultzone with a finite width and that (b) the structural damage within the zonewas caused, not primarily by ground acceleration, but by ground distortion.Along the right-lateral fault at Kaynali, the fault zone consists ofright-lateral movement at the main trace, a zone of right-lateral distortionnear the trace, bounded by left-lateral distortion. The 12 November 1999event in Turkey, like the ground deformation and fracturing at Landers,California (Johnson et al., 1994, 1996), thus affirmed a forgottenconclusion from the studies by Lawson (1908), Gilbert and Reid (1910)of the 1906 San Francisco earthquake that earthquake ruptures typicallyoccur throughout zones or belts, rather than along linear traces or planes.     

Prediction of Typhoon Tracks Using Dynamic Linear Models

This paper presents a study on the statistical forecasts of typhoon tracks. Numerical models have their own systematic errors, like a bias. In order to improve the accuracy of track forecasting, a statistical model called DLM (dynamic linear model) is applied to remove the systematic error. In the analysis of typhoons occurring over the western North Pacific in 1997 and 2000, DLM is useful as an adaptive model for the prediction of typhoon tracks.     

An alternative method for interpreting jet erosion test (JET) data: part 1. Theory

The jet erosion test (JET) is a widely applied method for deriving the erodibility of cohesive soils and sediments. There are suggestions in the literature that further examination of the method widely used to interpret the results of these erosion tests is warranted. This paper presents an alternative approach for such interpretation based on the principle of energy conservation. This new approach recognizes that evaluation of erodibility using the jet tester should involve the mass of soil eroded, so determination of this eroded mass (or else scour volume and bulk density) is required. The theory partitions jet kinetic energy flux into that involved in eroding soil, the remainder being dissipated in a variety of mechanisms. The energy required to erode soil is defined as the product of the eroded mass and a resistance parameter which is the energy required to entrain unit mass of soil, denoted J (in J/kg), whose magnitude is sought. An effective component rate of jet energy consumption is defined which depends on depth of scour penetration by the jet, but not on soil type, or the uniformity of the soil type being investigated. Application of the theory depends on experimentally determining the spatial form of jet energy consumption displayed in erosion of a uniform body of soil, an approach of general application. The theory then allows determination of the soil resistance parameter J as a function of depth of scour penetration into any soil profile, thus evaluating such profile variation in erodibility as may exist. This parameter J has been used with the same meaning in soil and gully erosion studies for the last 25 years. Application of this approach will appear in a companion publication as part 2. Copyright © 2017 John Wiley & Sons, Ltd.     

Very early diagenesis in a calcareous,organic-rich mudrock from Jordan

The diagenesis in the organic-rich Cretaceous to Eocene Al Hisa Phosphorite Formation (AHP), Muwaqqar Chalk Marl Formation (MCM) and Umm Rijam Chert-Limestone Formation (URC) formations of Jordan can be linked directly to the fluctuating sedimentary environment of this shelf depositional system in the Middle to Late Eocene, and its influence on the composition of the deposited sediment and the early burial diagenetic environment. Most cementation was early, mostly within the first 10 m of burial, perhaps entirely within the first 100 m of burial. We propose that the siliceous cements are derived from biogenic silica, probably of diatoms, deposited in a shelf of enhanced productivity. Volumetrically, the most important processes were the redistribution of biogenic opal-A (diatoms) and calcite to form pervasive, layered and nodular cements. The formation of the silica and carbonate cements is closely linked through the effects their dissolution and precipitation have on pore fluid chemistry and pH. The chert beds have a biogenic silica origin, formed through replacement of diatoms and radiolaria by opal-CT, and subsequently by quartz. Calcite cement has carbonate derived from microbial diagenesis of organic matter and calcium derived from seawater. The Mg for early dolomite may have been generated by replacement of opal-CT by quartz, ore dissolution of unstable high Mg calcite bioclasts. The silica and carbonate diagenetic processes are both linked to microbial diagenesis of organic matter, and are intimately linked in both time and space, with pH possibly influencing whether a silica or a carbonate mineral precipitates. The paucity of metal cations capable of precipitating as sulphides is crucial to the creation of acidic pore water favourable to silica precipitation, either as opal-CT, chalcedony or quartz. The lack of clay minerals as a sink for the Mg required for opal-CT polymerisation is the principal factor responsible for the remarkably early silica cementation. All the diagenetic processes, with the probable exception of the opal-CT to quartz transition are early, almost certainly within the first 10 m of burial, possibly much less. A paragenetic sequence is presented here based on these two cores that should be tested against a wider core distribution to see whether this diagenetic history can be generalised throughout the basin. Warm bottom water temperatures probably led to silica diagenesis at much shallower burial depths than occurs in many other sedimentary basins. Silicified layers, in turn, commonly host fractures, suggesting that mechanical properties of the strata began to differentiate at a very early stage in the burial cycle. This has wide implications for processes linking diagenesis to deformation.