TU Bergakademie Freiberg

The MATLAB™ toolbox MTEX provides a unique way to represent, analyse and interpret crystallographic preferred orientation, i.e. texture, based on integral (“pole figure”) or individual orientation (“EBSD”) measurements. In particular, MTEX comprises functions to import, analyse and visualize diffraction pole figure data as well as EBSD data, to estimate an orientation density function from either kind of data, to compute texture characteristics, to model orientation density functions in terms of model functions or Fourier coefficients, to simulate pole figure or EBSD data, to create publication ready plots, to write scripts for multiple use, and others. Thus MTEX is a versatile free and open-source software toolbox for texture analysis and modeling.

Profex is a graphical user interface for the Rietveld refinement program BGMN . Its interface focuses on preserving BGMN 's powerful and flexible scripting features by giving direct access to BGMN input files. Very efficient workflows for single or batch refinements are achieved by managing refinement control files and structure files, by providing dialogues and shortcuts for many operations, by performing operations in the background, and by providing import filters for CIF and XML crystal structure files. Refinement results can be easily exported for further processing. State-of-the-art graphical export of diffraction patterns to pixel and vector graphics formats allows the creation of publication-quality graphs with minimum effort. Profex reads and converts a variety of proprietary raw data formats and is thus largely instrument independent. Profex and BGMN are available under an open-source license for Windows, Linux and OS X operating systems.

The present paper analyzes the self‐generated explanations (from talk‐aloud protocols) that “Good” and “Poor” students produce while studying worked‐out examples of mechanics problems, and their subsequent reliance on examples during problem solving. We find that “Good” students learn with understanding: They generate many explanations which refine and expand the conditions for the action parts of the example solutions, and relate these actions to principles in the text. These self‐explanations are guided by accurate monitoring of their own understanding and misunderstanding. Such learning results in example‐independent knowledge and in a better understanding of the principles presented in the text. “Poor” students do not generate sufficient self‐explanations, monitor their learning inaccurately, and subsequently rely heavily on examples. We then discuss the role of self‐explanations in facilitating problem solving, as well as the adequacy of current AI models of explanation‐based learning to account for these psychological findings.

Interactions of "organic fluorine" have gained great interest not only in the context of crystal engineering, but also in the systematic design of functional materials. The first part of this tutorial review presents an overview on interactions known by organic fluorine. This involves π-π(F), C-F···H, F···F, C-F···π(F), C-F···π, C-F···M(+), C-F···C=O and anion-π(F) interactions, as well as other halogen bonds. The effect of the exchange of H vs. F is discussed by means of several examples and a short introduction to the young field of "fluorous" chemistry is given. The second part is dedicated to numerous applications of fluorine and fluorous interactions. It is shown how application of fluorination is used to enable a number of reactions, to improve materials properties and even open up new fields of research.

Soils act as sources and sinks for greenhouse gases (GHG) such as carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). Since both storage and emission capacities may be large, precise quantifications are needed to obtain reliable global budgets that are necessary for land-use management (agriculture, forestry), global change and for climate research. This paper discusses exclusively the soil emission related processes and their influencing parameters. It reviews soil emission studies involving the most important land-cover types and climate zones and introduces important measuring systems for soil emissions. It addresses current shortcomings and the obvious bias towards northern hemispheric data. When using a conservative average of 300 mg CO(2)e m(-2) h(-1) (based on our literature review), this leads to global annual net soil emissions of >= 350 Pg CO(2)e (CO(2)e = CO2 equivalents = total effect of all GHG normalized to CO2). This corresponds to roughly 21% of the global soil C and N pools. For comparison, 33.4 Pg CO2 are being emitted annually by fossil fuel combustion and the cement industry. (C) 2016 The Authors. Published by Elsevier GmbH. This is an open access article under the CC BY license.

A novel algorithm for ODF (orientation density function) estimation from diffraction pole figures is presented which is especially well suited for sharp textures and high-resolution pole figures measured with respect to arbitrarily scattered specimen directions, e.g. by area detectors. The estimated ODF is computed as the solution of a minimization problem which is based on a model of the diffraction counts as a Poisson process. The algorithm applies discretization by radially symmetric functions and fast Fourier techniques to guarantee smooth approximation and high performance. An implementation of the algorithm is freely available as part of the texture analysis software MTEX .

The article describes a classification system termed "extended functional groups" (EFG), which are an extension of a set previously used by the CheckMol software, that covers in addition heterocyclic compound classes and periodic table groups. The functional groups are defined as SMARTS patterns and are available as part of the ToxAlerts tool (http://ochem.eu/alerts) of the On-line CHEmical database and Modeling (OCHEM) environment platform. The article describes the motivation and the main ideas behind this extension and demonstrates that EFG can be efficiently used to develop and interpret structure-activity relationship models.

We present a novel technique for the determination of resistivity structures associated with arbitrary surface topography. The approach represents a triple-grid inversion technique that is based on unstructured tetrahedral meshes and finite-element forward calculation. The three grids are characterized as follows: A relatively coarse parameter grid defines the elements whose resistivities are to be determined. On the secondary field grid the forward calculations in each inversion step are carried out using a secondary potential (SP) approach. The primary fields are provided by a one-time simulation on the highly refined primary field grid at the beginning of the inversion process. We use a Gauss—Newton method with inexact line search to fit the data within error bounds. A global regularization scheme using special smoothness constraints is applied. The regularization parameter compromising data misfit and model roughness is determined by an L-curve method and finally evaluated by the discrepancy principle. To solve the inverse subproblem efficiently, a least-squares solver is presented. We apply our technique to synthetic data from a burial mound to demonstrate its effectiveness. A resolution-dependent parametrization helps to keep the inverse problem small to cope with memory limitations of today's standard PCs. Furthermore, the SP calculation reduces the computation time significantly. This is a crucial issue since the forward calculation is generally very time consuming. Thus, the approach can be applied to large-scale 3-D problems as encountered in practice, which is finally proved on field data. As a by-product of the primary potential calculation we obtain a quantification of the topography effect and the corresponding geometric factors. The latter are used for calculation of apparent resistivities to prevent the reconstruction process from topography induced artefacts.

We introduce and propose zircon M257 as a future reference material for the determination of zircon U‐Pb ages by means of secondary ion mass spectrometry. This light brownish, flawless, cut gemstone specimen from Sri Lanka weighed 5.14 g (25.7 carats). Zircon M257 has TIMS‐determined, mean isotopic ratios (2s uncertainties) of 0.09100 ± 0.00003 for 206 pb/ 238 U and 0.7392 ± 0.0003 for 207 pb/ 235 U. Its 206 pb/ 238 U age is 561.3 ± 0.3 Ma (unweighted mean, uncertainty quoted at the 95% confidence level); the U‐Pb system is concordant within uncertainty of decay constants. Zircon M257 contains ∼ 840 μg g −1 U (Th/U ∼ 0.27). The material exhibits remarkably low heterogeneity, with a virtual absence of any internal textures even in cathodoluminescence images. The uniform, moderate degree of radiation damage (estimated from the expansion of unit‐cell parameters, broadening of Raman spectral parameters and density) corresponds well, within the “Sri Lankan trends”, with actinide concentrations, U‐Pb age, and the calculated alpha fluence of 1.66 × 10 18 g −1 . This, and a (U+Th)/He age of 419 ± 9 Ma (2s), enables us to exclude any unusual thermal history or heat treatment, which could potentially have affected the retention of radiogenic Pb. The oxygen isotope ratio of this zircon is 13.9%o VSMOW suggesting a metamorphic genesis in a marble or calc‐silicate skarn.

Fritsch M. and Mueller P. (2004) Effects of new business formation on regional development over time, Regional Studies38, 961-975. In the analysis of the impact of new business formation on regional employment change, considerable time lags were identified. The structure and extent of these time lags were investigated by applying the Almon lag model and it was found that new firms can have both a positive and a negative effect on regional employment. The results indicate that the indirect effects of new business formation (crowding out of competitors, improvement of supply conditions and improved competitiveness) are of greater magnitude than the direct effect, i.e. the jobs created in the new entities. The peak of the positive impact of new businesses on regional development is reached about 8 years after entry. Fritsch M. et Mueller P. (2004) Les effets temporels de la création d'entreprise sur l'aménagement du territoire, Regional Studies38, 961-975. Cette analyse des effets de la création d'entreprise sur l'aménagement du terriotire identifie d'importants décalages dans le temps. On examine la structure et la portée de ces décalages en appliquant le modèle Almon. Il s'avère que les nouvelles entreprises font preuves d'effets postifs et négatifs sur l'emploi régional. Les résultats portent à croire que les effets indirects de la création d'entreprise (l'éviction des concurrents, l'amélioration des conditions de l'offre, et une compétitivité accrue) sont d'une plus grande importance que ne l'est l'effet direct, c'est à dire les emplois créés dans les nouveaux établissements. L'effet positif des nouvelles entreprises sur l'aménagement du territoire touche à son maximum environ huit années après la création de celles-là. Fritsch M. und Mueller P. (2004) Der Einfluss von Gründungsprozessen auf die Regionalentwicklung im Zeitablauf, Regional Studies38, 961-975. Für den Einfluss von Gründungsaktivitäten auf die Regionalentwicklung lassen sich erhebliche Zeitverzögerungen feststellen. Wir analysieren das Ausmaß und die Struktur dieser Zeitverzögerungen mit dem Almon-Lag Verfahren. Die Ergebnisse zeigen, dass Gründungen sowohl einen positiven als auch einen negativen Einfluss auf das Beschäftigungsniveau haben können. Allgemein scheinen die indirekten Effekte des Gründungsgeschehens (Verdrängung etablierter Konkurrenten, Verbesserung des Angebots und gesteigerte Wettbewerbsfähigkeit) stärker ausgeprägt zu sein als der direkte Effekt, gemessen als die in den neuen Firmen entstandenen Arbeitsplätze. Das Maximum des positiven Einflusses der Gründungen auf die Regionalenwicklung wird nach ca. acht Jahren erreicht. Fritsch M. y Mueller P. (2004) Los efectos de la formación de nuevas empresas en el desarrollo regional a lo largo del tiempo, Regional Studies38, 961-975. En el análisis del impacto de la formación de nuevas empresas sobre la variación en el empleo regional se identifican retardos temporales considerables. Nosostros investigamos la estructura y el grado de estos retardos mediante la aplicación del modelo de retardos de Almon y encontramos que las nuevas empresas pueden tener tanto un efecto positivo como negativo en el empleo regional. Los resultados indican que los efectos indirectos de la formación de nuevas empresas (desplazamiento de competidores, mejora de las condiciones de oferta y mejora de la competitividad) son de una magnitud mayor que el efecto directo, es decir, los empleos que se crean en las nuevas entidades. El impacto positivo de las nuevas empresas en el desarrollo regional alcanza su nivel más alto unos ocho años después de su entrada.

The 'iron bacteria' are a collection of morphologically and phylogenetically heterogeneous prokaryotes. They include some of the first micro-organisms to be observed and described, and continue to be the subject of a considerable body of fundamental and applied microbiological research. While species of iron-oxidizing bacteria can be found in many different phyla, most are affiliated with the Proteobacteria. The latter can be subdivided into four main physiological groups: (i) acidophilic, aerobic iron oxidizers; (ii) neutrophilic, aerobic iron oxidizers; (iii) neutrophilic, anaerobic (nitrate-dependent) iron oxidizers; and (iv) anaerobic photosynthetic iron oxidizers. Some species (mostly acidophiles) can reduce ferric iron as well as oxidize ferrous iron, depending on prevailing environmental conditions. This review describes what is currently known about the phylogenetic and physiological diversity of the iron-oxidizing proteobacteria, their significance in the environment (on the global and micro scales), and their increasing importance in biotechnology.

Abstract. Photogrammetry and geosciences have been closely linked since the late 19th century due to the acquisition of high-quality 3-D data sets of the environment, but it has so far been restricted to a limited range of remote sensing specialists because of the considerable cost of metric systems for the acquisition and treatment of airborne imagery. Today, a wide range of commercial and open-source software tools enable the generation of 3-D and 4-D models of complex geomorphological features by geoscientists and other non-experts users. In addition, very recent rapid developments in unmanned aerial vehicle (UAV) technology allow for the flexible generation of high-quality aerial surveying and ortho-photography at a relatively low cost.The increasing computing capabilities during the last decade, together with the development of high-performance digital sensors and the important software innovations developed by computer-based vision and visual perception research fields, have extended the rigorous processing of stereoscopic image data to a 3-D point cloud generation from a series of non-calibrated images. Structure-from-motion (SfM) workflows are based upon algorithms for efficient and automatic orientation of large image sets without further data acquisition information, examples including robust feature detectors like the scale-invariant feature transform for 2-D imagery. Nevertheless, the importance of carrying out well-established fieldwork strategies, using proper camera settings, ground control points and ground truth for understanding the different sources of errors, still needs to be adapted in the common scientific practice.This review intends not only to summarise the current state of the art on using SfM workflows in geomorphometry but also to give an overview of terms and fields of application. Furthermore, this article aims to quantify already achieved accuracies and used scales, using different strategies in order to evaluate possible stagnations of current developments and to identify key future challenges. It is our belief that some lessons learned from former articles, scientific reports and book chapters concerning the identification of common errors or "bad practices" and some other valuable information may help in guiding the future use of SfM photogrammetry in geosciences.

Abstract One of the major hurdles of Ni‐rich cathode materials Li 1+ x (Ni x Co z Mn z ) w O 2 , y > 0.5 for lithium‐ion batteries is their low cycling stability especially for compositions with Ni ≥ 60%, which suffer from severe capacity fading and impedance increase during cycling at elevated temperatures (e.g., 45 °C). Two promising surface and structural modifications of these materials to alleviate the above drawback are (1) coatings by electrochemically inert inorganic compounds (e.g., ZrO 2 ) or (2) lattice doping by cations like Zr 4+ , Al 3+ , Mg 2+ , etc. This paper demonstrates the enhanced electrochemical behavior of Ni‐rich material LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM811) coated with a thin ZrO 2 layer. The coating is produced by an easy and scalable wet chemical approach followed by annealing the material at ≥700 °C under oxygen that results in Zr doping. It is established that some ZrO 2 remains even after annealing at ≥800 °C as a surface layer on NCM811. The main finding of this work is the enhanced cycling stability and lower impedance of the coated/doped NCM811 that can be attributed to a synergetic effect of the ZrO 2 coating in combination with a zirconium doping.

Viruses as well as other (bio-)colloids possess a pH-dependent surface charge in polar media such as water. This electrostatic charge determines the mobility of the soft particle in an electric field and thus governs its colloidal behaviour which plays a major role in virus sorption processes. The pH value at which the net surface charge switches its sign is referred to as the isoelectric point (abbreviations: pI or IEP) and is a characteristic parameter of the virion in equilibrium with its environmental water chemistry. Here, we review the IEP measurements of viruses that replicate in hosts of kingdom plantae, bacteria and animalia. IEPs of viruses are found in pH range from 1.9 to 8.4; most frequently, they are measured in a band of 3.5 < IEP < 7. However, the data appear to be scattered widely within single virus species. This discrepancy is discussed and should be considered when IEP values are used to account for virus sorption processes.

Forestry statistics is an important field of applied statistics with a long tradition. Many forestry problems can be solved by means of point processes or marked point processes. There, the “points ”are tree locations and the “marks ” are tree characteristics such as diameter at breast height or degree of damage by environmental factors. Point process characteristics are valuable tools for exploratory data analysis in forestry, for describing the variability of forest stands and for understanding and quantifying ecological relationships. Models of point processes are also an important basis of modern single-tree modeling, that gives simulation tools for the investigation of forest structures and for the prediction of results of forestry operations such as plantation and thinning.

It is shown that molecular electronic circular dichroism (CD) can systematically be investigated by means of adiabatic time-dependent density functional theory (TDDFT). We briefly summarize the theory and outline its extension for the calculation of rotatory strengths. A new, efficient algorithm has been implemented in the T urbomole program package for the present work, making large-scale applications feasible. The study of circular dichroism in helicenes has played a crucial role in the understanding of molecular optical activity. We present the first ab initio simulation of electronic CD spectra of [ n ]helicenes, n = 4−7, 12. Substituent effects are considered for the 2,15-dicyano and 2,15-dimethoxy derivates of hexahelicene; experimental CD spectra of these compounds were newly recorded for the present work. The calculations correctly reproduce the most important spectral features and greatly facilitate interpretation. We propose assignments of the low-energy bands in terms of individual excited states. Changes in the observed spectra depending on the number of rings and substitution patterns are worked out and rationalized. Merits and limitations of TDDFT in chemical applications are discussed.

Ni-rich materials of layered structure LiNixCoyMnzO2, x > 0.5, are promising candidates as cathodes in high-energy-density Li-ion batteries for electric vehicles. The structural and cycling stability of Ni-rich cathodes can be remarkably improved by doping with a small amount of extrinsic multivalent cations. In this study, we examine development of a fast screening methodology for doping LiNi0.8Co0.1Mn0.1O2 with cations Mg2+, Al3+, Si4+, Ti4+, Zr4+, and Ta5+ by a “top-down” approach. The cathode material is coated by a precursor layer that contains the dopant, which then is introduced into the particles by diffusion during heat treatment at elevated temperatures. The methodology described herein can be applied to Ni-rich cathode materials and allows relatively easy and prompt identification of the most promising dopants. Then further optimization work can lead to development of high-capacity stable cathode materials. The present study marks Ta5+ cations as very promising dopants for Ni-rich NCM cathodes.

Twenty fresh frozen cadaver shoulders were dissected in order to study the rotator cable-crescent complex. The rotator crescent is a term that we have used to describe the thin, crescent-shaped sheet of rotator cuff comprising the distal portions of the supraspinatus and infraspinatus insertions. The crescent was found to be bounded on its proximal margin by a thick bundle of fibers that we have called the rotator cable. This cable-crescent configuration was found to consistently span the insertions of supraspinatus and infraspinatus tendons. The dimensions of the rotator cable and crescent were measured by a digital micrometer. The rotator cable was found to be a very substantial structure, averaging 2.59 times the thickness of the rotator crescent that it surrounded. This anatomic study supports the concepts of stress-shielding of the rotator crescent by the stout rotator cable and stress transfer by this loaded cable system.

The amplitude of the extended x-ray-absorption fine structure of concentrated samples measured in the fluorescence mode (FLEXAFS) as well as the overall shape of the fluorescence-yield spectra strongly depend on the detection geometry through the self-absorption effect. In these cases, a conventional EXAFS analysis can lead to systematic errors in the determination of physical parameters. We studied the distortions in the FLEXAFS spectra through the self-absorption effect measuring the FLEXAFS of a NiO single crystal above the oxygen K edge for various detection geometries. We show that knowing the stoichiometry of the sample we can fully correct for the self-absorption effect using a simple theory and obtain the correct, geometry-independent oxygen EXAFS of NiO. The correction procedure presented here for the prototype system of NiO is generally applicable and should be the first step in the analysis of FLEXAFS data of concentrated samples. We calculate the information depth of the fluorescence detection as a function of the experimental geometry. The knowledge of the self-absorption in relationship to the information depth allows the determination of the optimum experimental setup.

In this bibliography main directions of research as well as main fields of applications of bilevel programming problems and mathematical programs with equilibrium constraints are summarized. Focus is also on the difficulties arising from nonuniqueness of lower-level optimal solutions and on optimality conditions.