Bernhardt Saini-Eidukat

Virtual environments for education

WWWIC, the NDSU World Wide Web Instructional Committee, is engaged in developing a range of virtual environments for education. These projects span a range of disciplines, from earth science to anthropology, and from business to biology. However, all of these projects share a strategy, a set of assumptions, an approach to assessment, and an emerging tool set, which allows each to leverage from the insights and advances of the others.

Cadmium and associated metals in soils and sediments of wetlands across the Northern Plains, USA

Cadmium, present locally in naturally high concentrations in the Northern Plains of the United States, is of concern because of its toxicity, carcinogenic properties, and potential for trophic transfer. Reports of natural concentrations in soils are dominated by dryland soils with agricultural land uses, but much less is known about cadmium in wetlands. Four wetland categories - prairie potholes, shallow lakes, riparian wetlands, and river sediments - were sampled comprising more than 300 wetlands across four states, the majority in North Dakota. Cd, Zn, P, and other elements were analyzed by ICP-MS, in addition to pH and organic matter (as loss-on-ignition). The overall cadmium content was similar to the general concentrations in the areas soils, but distinct patterns occurred within categories. Cd in wetland soils is associated with underlying geology and hydrology, but also strongly with concentrations of P and Zn, suggesting a link with agricultural land use surrounding the wetlands.

Erionite and offretite from the Killdeer Mountains, Dunn County, North Dakota, U.S.A.

Abstract The carcinogenic potential of erionite has sparked concern about human exposure in areas where it is present in regional bedrock. The Arikaree Formation in western North Dakota contains altered tuffaceous units with authigenic zeolites. We sampled stratigraphic profiles in the Killdeer Mountains, Dunn County, North Dakota, to determine the distribution and chemical composition of zeolites. Powder X-ray diffraction, SEM/EDS and electron microprobe analyses were carried out on sample concentrates. Only samples stratigraphically in or below the distinctive burrowed marker unit were found to contain zeolites. Erionite and offretite were the most common zeolites identified, with offretite being more abundant based on frequency of measured Mg/(Ca+Na) ratios. Intermediate chemical compositions could be natural or due to intimate intergrowths of the two minerals. A better understanding is needed of the potential toxicity across the range of erionite and offretite compositions.

Contrasts Between Platinum Group Element Contents and Biotite Compositions of Duluth Complex Troctolitic and Anorthositic Series Rocks

SummaryThis paper presents new data on sulfide assemblages, platinum group elements (PGEs) and halogen contents of biotites in anorthositic series rocks from the Duluth Complex. The data are contrasted with similar data from troctolitic series rocks. Sulfides occur in only trace amounts in anorthositic series rocks as interstitial grains, inclusions in plagioclase, and veinlets cutting olivine. These textures and the sulfide assemblage (pyrrhotite, pentlandite and chalcopyrite) are similar to the sulfide mineralization in troctolitic series rocks. However, the sulfide assemblage is dominated by chalcopyrite in anorthositic rocks. The highest concentration of PGEs in anorthositic series rocks found to date is 163 ppb Pt, with the bulk of the data at limits of detection. PGE contents of troctolitic series rocks range from 100=200 ppb Pt + Pd to an anomalously high 14 ppm Pt + Pd over a one meter interval. The variation of F/Cl ratios with Fe-Mg compositions of Duluth Complex magmatic biotites may be interpreted to imply equilibration with a fluid phase of constant composition. We have no definitive interpretation of the significance of the distinctly different biotite compositions reported from the Stillwater and Bushveld Complexes.ZusammenfassungDiese Arbeit stellt neue Ergebnisse über die Sulfidparagenesen, die Platingruppenelemente (PGE) und die Gehalte an Halogeniden in Biotit aus den anorthositischen Gesteinsserien des Duluth Komplexes vor. Sie werden mit Daten aus den Troktoliten verglichen. Sulfide treten nur im Spuren in den anorthositischen Gesteinen in Form von interstitialen Körnern, von Einschlüssen im Plagioklas und von Olivin durchsetzenden Rissen auf. Diese Texturen und die Sulfidparagenese (Magnetkies, Pentlandit und Kupferkies) sind mit Sulfidmineralisationen in den troktolitischen Gesteinen zu vergleichen. Kupferkies ist allerdings das dominierende Sulfid in den anorthositischen Gesteinen. Die höchsten bis jetzt bekannten PGE-Konzentrationen von 163 ppb Pt sind ebenfalls an diese Gesteine geknüpft. Der Grossteil der Proben zeigt Gehalte im Bereich der Nachweisgrenze. Die PGE-Gehalte der troktolitischen Gesteine schwanken im Bereich von 100–200 ppb Pt und Pd mit über ein Intervall von einem Meter abnormal hohen Gehalten von 14 ppm Pt und Pd.Die Schwankungen der F/Cl Verhältnisse mit den Fe-Mg Gehalten magmatischer Biotite des Duluth-Komplexes können als Hinweise auf Gleichgewichtsbedingungen mit einer fluiden Phase konstanter Zusammensetzung interpretiert werden.Die Bedeutung dieser im Vergleich zum Stillwater- und Bushveldkomplex eindeutig verschiedenen Biotitzusammensetzungen ist noch unklar.

Research on role-based learning technologies

One of the goals of science education is to familiarize students with an intellectual framework based on established scientific principles and general approaches that can later be used to solve science-based problems. Science is also content-based, and students must master the content of a discipline in order to succeed. The challenge for science educators is to develop educational tools and methods that deliver the principles but at the same time teach the important content material, but in a meaningful way. The paper describes research based on experimental virtual role-based environments built to explore the following beliefs: educational technology should capitalize on the natural human propensity for role-playing; students will be willing to assume roles if the environment makes it easy to do, and if the environment reinforces role-playing through careful crafting of explicit tutorial components; that educational software should be engaging, entertaining, attractive, interactive, and flexible: in short, game-like. The experiences provided to the student within these virtual worlds can be both meaningful and authentic, although some trade-offs are required to make them fun, challenging, and occasionally unpredictable.

Web-phreeq: a WWW instructional tool for modeling the distribution of chemical species in water

Abstract A WWW-based tool, WEB-PHREEQ, was developed for classroom teaching and for routine calculation of low temperature aqueous speciation. Accessible with any computer that has an internet-connected forms-capable WWW-browser, WEB-PHREEQ provides user interface and other support for modeling, creates a properly formatted input file, passes it to the public domain program PHREEQC and returns the output to the WWW browser. Users can calculate the equilibrium speciation of a solution over a range of temperatures or can react solid minerals or gases with a particular water and examine the resulting chemistry. WEB-PHREEQ is one of a number of interactive distributed-computing programs available on the WWW that are of interest to geoscientists.

The metamorphosed molybdenum vein-type deposit of the Alpeinerscharte, Tyrol (Austria) and its relation to Variscan granitoids

The molybdenite deposit of the Alpeinerscharte (Austria) is situated in Variscan greenschist- to amphibolite-facies metamorphosed granodiorites and granites of the western Tauern Window. These granitoids represent strongly fractionated calc-alkaline I-type magmas with minor S-type components and reveal post-orogenic affinities. Molybdenum contents (average 4.3 ppm) are slightly above the general background of average granites. Molybdenite mineralization is restricted to narrow quartz veins and quartz vein selvages which are presently composed of biotite and (almandine-grossular) garnet. These selvages show geochemical features typical of intermediate argillic alteration in a hydrothermal system postdating granite intrusion: instability of plagioclase causes removal of Na, Ba, Sr, Pb and Eu, while K and Ca remain nearly constant. Rare earth elements (apart from Eu) and metals are extremely enriched. Application of Fe-Mg exchange (garnet-biotite) and oxygen isotope (quartz-garnet, quartz-plagioclase) geothermometers to vein selvage mineral assemblages reveals temperatures of the late-Alpine (35–55 Ma) metamorphic overprint (∼540°C, 7–10 kbar). Leucocratic rocks composed of mainly orthoclase and plagioclase are occasionally spatially related to molybdenite-bearing veins; they are interpreted as episyenites formed by hydrothermal alteration of the host granite. This episyenitic alteration is characterized by a mass loss of ca. 30%, relative enrichment of plagioclase components, extreme depletion of Si, and minor depletion of Fe, Zn, Cu and Mo.

Characterization of zinc oxide nanoparticle (nZnO) alginate beads in reducing gaseous emission from swine manure

ABSTRACT Hydrogen sulfide (H2S) and greenhouse gases’ emission from livestock production facilities are of concern to human welfare and the environment. Application of nanoparticles (NPs) has emerged as a potential option for minimizing these gaseous emissions. Application of bare NPs, however, could have an adverse effect on plants, soil, human health, and the environment. To minimize NPs’ exposure to the environment by recovering them, NPs were entrapped in polymeric beads for treating livestock manure. The objectives of the research were to understand the mechanism of gaseous reduction in swine manure treated for 33 days with zinc oxide nanoparticles (nZnO) or nZnO-entrapped alginate (alginate-nZnO) beads by different characterization techniques. Headspace gases from treated manure flasks were collected in 2–6-day intervals during the experimental period and were analyzed for methane (CH4), carbon dioxide (CO2), and H2S concentrations. The microbial analysis of manure was carried out using bacterial plate counts and Real-Time Polymerase Chain Reaction methods. Morphology and chemical composition of alginate-nZnO beads were analyzed by Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), and X-ray Photoelectron Spectroscopy (XPS). Alginate-nZnO beads or bare nZnO proved to be an effective NP in reducing H2S (up to 99%), CH4 (49–72%), and CO2 (46–62%) from manure stored under anaerobic conditions and these reductions are likely due to the microbial inhibitory effect from nZnO, as well as chemical conversion. Both SEM-EDS and XPS analysis confirmed the presence of zinc sulfide (ZnS) in the beads, which is likely formed by reacting nZnO with H2S.

Factors Controlling the Fractionation and Seasonal Mobility Variations of Ga and In in Systems Impacted by Acidic Thermal Waters: Effects of Thermodynamics and Bacterial Activity

This work assessed both the fractionation and the seasonal mobility variations of Ga and In in systems impacted by acidic thermal waters. This was accomplished by performing thermodynamic calculations using the PHREEQC algorithm and by assessing the activity of acidophilic iron-oxidizing bacteria. The pH of the Kusatsu thermal waters in Gunma Prefecture, central Japan, is rapidly increased following the addition of a lime suspension. After an abrupt pH increase, under which conditions free ions of Ga and In and their complexes with Cl− and SO42− exist only in negligible quantities, the majority of dissolved Ga and In is removed by sorption onto suspended hydrous ferric oxides (HFOs). These HFOs are then transported to an artificial lake without significant sedimentation along the river. Subsequently, the suspended HFOs settle out and are added to sediments without significant fractionation between Ga and In. The Tamagawa thermal waters in Akita Prefecture, northeast Japan, are also treated with lime. However, complete neutralization requires mixing with some tributary streams, leading to a gradual downstream increase in pH. Dissolved Ga is, in general, sorbed by HFOs in upstream areas, leading to wide dispersal of Ga across the entire watershed. In comparison, In is transported to the lake inlet predominantly as a Cl− complex species without significant removal along the river, with the majority being precipitated in an artificial lake, where Cl− concentrations are too low to form stable complex species with In, and thus, dissolved In is sorbed by HFOs. As a result, In is effectively concentrated within downstream lakebed sediments, whereas Ga is dispersed along the river. Seasonal variations in Ga mobility within the Tamagawa field between snowmelt and low-flow seasons are primarily controlled by pH, because hydrolysis reactions of these metals, which are related to sorption reactions, tend to occur in the upstream regions in the snowmelt season. However, under warmer conditions, HFO formation preferably occurs due to the activity of acidophilic iron-oxidizing bacteria. Thus, under similar pH variations, dissolved Ga is more effectively removed by HFOs during warmer seasons. On the contrary, because HFOs are abundantly formed in low-flow season, even under colder conditions, before In hydrolysis reaction starts to occur, In mobility is less affected by water temperature and then bacterial activity.

Material Analysis of Lithic Flaking Debris

volve the use ofkeys, comparative collections, and sorting of materials into lots based on color, lus ter, texture, and inclusions (such as fossils, oo lites, and vugs). While Morrow does not apply his system to materials derived from till, Bakkens system is more or less explicitly directed at the examination of till-derived raw materials. Lithic collections may be characterized using two different methods, here termed the macro scopic and microscopic. The macroscopic method is dependent on the use of comparative lithic col lections, on comparison of lithic features visible to the unaided eye, or with the aid of a 1 Ox hand lens. The microscopic method is essentially pet rographic, involving the use of polarized light microscopes and the identification of mineralogi cal components in lithic thin sections. Over the past few decades various petrographic and geochemical descriptions of northern Plains lithic materials have appeared in the literature. Some relevant examples are Porter (1962) for Tongue River silica and Bijou Hills quartzite, Loendorf et al. (1984) for Rainy Buttes silicified wood, Church (1994) for Ogalalla orthoquartzite (formerly Bijou Hills quartzite), Campling (1980) for Swan River chert, and Clayton et al. (1970) for Knife River flint. Others have described or discussed northern Plains lithics in more conventional archaeologi cal terms. Examples are Ahler (1977), Anderson (1978), D. Fredlund (1976), and Low (1996). Bakken (1997) has assembled a review of lithics used in prehistoric Minnesota, and Morrow (1994) provides a key for identification of lithics com monly found in Iowa. While archaeologists are becoming more so phisticated in description and analysis of lithic material, many archaeological studies are done without the benefit of petrographic analysis of thin sections, X-ray Diffraction (XRD), Scanning Elec tron Microscopy (SEM), or other laboratory tech niques. The most useful of these techniques for archaeological identification of raw materials is petrographic description of thin sections. In many cases, optical microscopy using polarized light allows an investigator to identify the minerals that comprise a sample. Details of the textural rela tionships between mineral grains are clearly seen when they are magnified between l(M500x. The abundance of each mineral species present can be estimated, and in many cases, the composition and growth conditions of the rock can be interpreted. For extremely fine-grained rocks, optical micros copy does not provide the necessary magnifica tion, and SEM analysis must be undertaken. A review of the applications of petrography to ar chaeology is provided by Kempe and Harvey (1983). Given these two methods, questions sometime arise regarding the reliability of the macroscopic method. Specifically, are lithic raw material names assigned by archaeologists on the basis of macro scopic examination corroborated by thin section descriptions? For this reason a simple experiment was set up during the analysis of the Rustad lithic materials. The lithic collection was divided into raw material classes macroscopically, following a procedure similar to that described by Bakken (1997) and Morrow (1994). The procedure devel oped out of the recommendations of these research ers is to inspect lithic collections in aggregate, that is, to review large quantities of lithic material al together, noting the range of variation across the collection. As this is done, the rough outlines of a lithic classification are developed. Next, a com parative collection of lithic material is used, along with basic descriptive information about the rock types that appear to be represented. Items from each provenience unit are then placed in one or another of the categories, paying special attention