Thermodynamic properties, crystal structures, phase relations and isotopic studies of selected copper oxysalts

Die Variabilität in der chemischen und isotopischen Zusammensetzung sowie die kristallchemischen Eigenschaften sekundärer Kupferminerale sind von großer Bedeutung für das Verständnis der Bildung und Entwicklung von Oxidationszonen in Erzlagerstätten. Unter anderem sind Kupferarsenate und –karbonate häufige und weit verbreitete Minerale in solchen Oxidationszonen. Ein Teil dieser Arbeit konzentriert sich auf die Bildung dieser Minerale, deren thermodynamische Eigenschaften, Stabilitätsbereiche und kristallchemische Daten. Die untersuchten Minerale sind Lirokonit, Pushcharovskit, Geminit, Adamit und Zinkolivenit sowie die Olivenit–Libethenit Mischkristallreihe. Die erhaltenen thermodynamischen Daten wurden genutzt, um Stabilitätsfelder und Bildungsbedingungen der zuvor genannten sekundären Kupferminerale zu modellieren und mit natürlichen Paragenesen verschiedener Erzlagerstätten zu vergleichen. Für die Olivenit–Libethenit Mischkristallreihe zeigen die Ergebnisse, dass eine komplette Mischkristallreihe ohne Mischungslücke existiert, wobei der Einbau von Phosphor gegenüber Arsen bevorzugt wird. Der andere Teil dieser Arbeit konzentriert sich auf die isotopische Fraktionierung von Kupfer-, Sauerstoff- und Wasserstoff-Isotopen zwischen Malachit und wässriger Lösung. Die Fraktionierungsverschiebung von Kupfer von –0.16 ± 0.05 ‰. impliziert, dass chemische Reaktionen von Mineralen, ohne Änderung des Redoxzustandes, nur eine geringfügige Kupferisotopenfraktionierung hervorbringen. Der berechnete Fraktionierungsfaktor von Sauerstoff und Wasserstoff wird dazu verwendet, um die isotopische Zusammensetzung der Bildungswässer der natürlichen Malachit-Proben von Lokalitäten weltweit zu bestimmen und mit der isotopischen Zusammensetzung von Regenwässern nahegelegener Stationen zu vergleichen. Zusammen mit den Kupferisotopen der natürlichen Malachit-Proben kann man annehmen, dass alle untersuchten Malachite supergene Proben sind, welche sich aus meteorischem Wasser bildeten.Indeed, I had to write this thesis by myself, but for its success, the support and guidance of a lot of people were involved. For this, I want to thank them. Special thanks go to my advisors – without them it would not have been possible to write a dissertation at the Institute of Geosciences at the FSU Jena. I want to thank Prof. Dr. Juraj Majzlan for his guidance and support through my Ph.D. work. He gave me the chance to meet a lot of new people and researchers that I was able to work with. I also want to thank Prof. Dr. Thorsten Schäfer for his support and his feedback, who kindly agreed to be my second reviewer for this thesis. Furthermore, I would like to thank PD Dr. Klaus-Dieter Grevel, for spending hours discussing data with me. I benefited greatly from his help and his ideas. He constantly motivated me throughout my Ph.D. research. Moreover, I would like to thank all the researchers I was able to work with. Prof. Dr. Ryan Mathur, for his constructive discussions and feedback on my isotopic work. He kept in touch with me even when it was in long time intervals. Rastislav Milovský, who showed me his lab and was helpful with all questions concerning stable isotopes. Jakub Plášil for the single crystal measurements and his needed help to understand and use JANA. Edgar Dachs and Artur Benisek, for doing the calorimetric measurements that completed the thermodynamic data for my studied phases. Martin Števko and Mike Rumsey for sharing their knowledge about copper arsenate ore deposits. Frank Bok for his constant help with Geochemist’s workbench®. Maciej Manecki with his input and support to synthesize the solid solution. Additionally, I want to thank Marcel Görn, Patrick Haase, Julia Hermann, Wiebke Nowakand Marcus Böhm for their (mental) support throughout the whole Ph.D. work, including very long discussions and conversations. Finally, and most important, I want to thank my family, Peter, Christa, und Thomas Plumhoff, Christa Balz and Steffen Schuhmann for their patience and support, especially during the stressful and final part of my Ph.D. thesis

Establishing an Environmental Audit Privilege to Promote Implementation of the ISO 14000 Standards

This comment will attempt to address some of the issues surrounding the ISO 14000 standards and also the Eco-Management and Audit Scheme or EMAS standards. Part II of the comment will discuss the evolution and need for international standards such as ISO 14000 and EMAS. Part III will analyze the challenges to successful implementation of ISO and EMAS, particularly concentrating on the problems which may arise from the proliferation of information due to increased EMS audits. Part IV suggests that ISO audit privilege legislation be adopted by the U.S. Congress and that an ISO audit policy be adopted by the U.S. Environmental Protection Agency (EPA). Finally, part V will provide concluding thoughts

Management Legacy Affects on Cover Crop Productivity and the Potential to Reduce Nutrient Leaching from Farms

Cover cropping is an ecological management practice that provides a variety of ecosystem functions to farms, such as increasing soil organic matter content and improving nutrient retention. Background soil fertility due to unique management legacies is expected to influence the productivity of cover crops and subsequently mediate their effects on ecosystem functions related to nutrient retention. We used a long-term experiment at Michigan State University’s Kellogg Biological Station to test the legacy effects of four distinct management systems (ranging from conventional to certified organic) on the production and function of crimson clover and cereal rye cover crops grown alone and in mixture, with a focus on the potential to reduce nitrate leaching. Cover crops were planted following winter wheat harvest in the summer of 2019 and corn was planted in all treatments the following spring after cover crop termination. We applied bromide as a conservative tracer of water and anion flow in the soil profile to assess management legacy and cover crop treatment effects on potential anion leaching. We found that via changes to soil fertility, management legacies influenced cover crop productivity and species composition in mixture: in the legacies with lower soil fertility, crimson clover was more competitive than rye and dominated the mixture. Legacies with higher soil fertility—which were those with a history of ecological nutrient management—had higher average cover crop biomass (mean = 3357 kg ha-1 ) and a higher percent recovery of bromide (mean = 33.28%), an estimate of soil anion retention. Further, percent recovery of bromide was positively correlated with cover crop biomass (r 2 =.17) and the free particulate organic matter fraction (r 2 =.29), indicating that the effect of management legacy on cover crop function is mediated by cover crop production and background soil fertility. This experiment reveals complex interactions between soil fertility, cover crop growth, and nutrient leaching potential that depend on soil conditions resulting from specific management regimes.Master of ScienceSchool for Environment and SustainabilityUniversity of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/167297/1/Marta_Plumhoff_Thesis.pd

Comparing Image Quality in Phase Contrast subμ\mu X-Ray Tomography -- A Round-Robin Study

How to evaluate and compare image quality from different sub-micrometer (sub$\mu$) CT scans? A simple test phantom made of polymer microbeads is used for recording projection images as well as 13 CT scans in a number of commercial and non-commercial scanners. From the resulting CT images, signal and noise power spectra are modeled for estimating volume signal-to-noise ratios (3D SNR spectra). Using the same CT images, a time- and shape-independent transfer function (MTF) is computed for each scan, including phase contrast effects and image blur ($\mathrm{MTF_{blur}}$). The SNR spectra and MTF of the CT scans are compared to 2D SNR spectra of the projection images. In contrary to 2D SNR, volume SNR can be normalized with respect to the object's power spectrum, yielding detection effectiveness (DE) a new measure which reveals how technical differences as well as operator-choices strongly influence scan quality for a given measurement time. Using DE, both source-based and detector-based sub$\mu$ CT scanners can be studied and their scan quality can be compared. Future application of this work requires a particular scan acquisition scheme which will allow for measuring 3D signal-to-noise ratios, making the model fit for 3D noise power spectra obsolete

Comparison of 2D and 3D Plasma Electrolytic Oxidation (PEO)-Based Coating Porosity Data Obtained by X-ray Tomography Rendering and a Classical Metallographic Approach

In this work, the porosity of plasma electrolytic oxidation (PEO)-based coatings on Al- and Mg-based substrates was studied by two imaging techniques-namely, SEM and computer microtomography. Two approaches for porosity determination were chosen; relatively simple and fast SEM surface and cross-sectional imaging was compared with X-ray micro computed tomography (microCT) rendering. Differences between 2D and 3D porosity were demonstrated and explained. A more compact PEO coating was found on the Al substrate, with a lower porosity compared to Mg substrates under the same processing parameters. Furthermore, huge pore clusters were detected with microCT. Overall, 2D surface porosity calculations did not show sufficient accuracy for them to become the recommended method for the exact evaluation of the porosity of PEO coatings; microCT is a more appropriate method for porosity evaluation compared to SEM imaging. Moreover, the advantage of 3D microCT images clearly lies in the detection of closed and open porosity, which are important for coating properties

Publikationsprozesse für Forschungsdaten mit PubFlow : von der Erhebung und Verarbeitung zur Archivierung und Publikation

Project report. Die Ergebnisse des DFG-geförderten Projektes PubFlow werden präsentiert. PubFlow zielt darauf ab, Publikationsprozesse für Forschungs- daten von der Erhebung und der Verarbeitung bis hin zur Archivierung und Publikation zu unterstützen. Die exemplarische Implementierung von PubFlow orientiert sich an etablierten Arbeitsabläufen des Forschungsdatenmanagements in den Meereswissenschaften

Imaging Invasion: Micro-CT imaging of adamantinomatous craniopharyngioma highlights cell type specific spatial relationships of tissue invasion.

Tissue invasion and infiltration by brain tumours poses a clinical challenge, with destruction of structures leading to morbidity. We assessed whether micro-CT could be used to map tumour invasion in adamantinomatous craniopharyngioma (ACP), and whether it could delineate ACPs and their intrinsic components from surrounding tissue.Three anonymised archival frozen ACP samples were fixed, iodinated and imaged using a micro-CT scanner prior to the use of standard histological processing and immunohistochemical techniques.We demonstrate that micro-CT imaging can non-destructively give detailed 3D structural information of tumours in volumes with isotropic voxel sizes of 4-6 microns, which can be correlated with traditional histology and immunohistochemistry.Such information complements classical histology by facilitating virtual slicing of the tissue in any plane and providing unique detail of the three dimensional relationships of tissue compartments