Stelleninhaber geht – Wissen bleibt!

In Deutschland nimmt der Anteil älterer Arbeitnehmerinnen und Arbeitnehmer tendenziell zu. Deshalb muss sich die Bibliotheksleitung verstärkt auf das altersbedingte Ausscheiden älterer Arbeitnehmer einstellen. Eine langjährige Fachkraft verfügt über spezielles Erfahrungswissen im direkten Aufgabenfeld. Die Bibliotheksleitung muss den Transfer allen relevanten Wissens, dazu gehört das Erfahrungswissen, vom Stelleninhaber auf seinen Nachfolger ermöglichen und unterstützen. Am Beispiel der Universitätsbibliothek der Bergakademie Freiberg wird untersucht, wie das Wissensmanagement im Rahmen eines Stellenwechsels derzeit geregelt ist. Das geschieht mit Hilfe von Tiefeninterviews in verschiedenen Abteilungen. Die Auswertung der Interviews bildet die Basis für ein Konzept für das Wissensmanagement beim Stellenwechsel an der UB Freiberg. Das Konzept benennt u. a. Maßnahmen zur Identifikation des stellenbezogenen Wissens, Maßnahmen zur Dokumentation des relevanten Wissens und Instrumente zur Wissensweitergabe beim Stellenwechsel

The Mixing of K⁺, (<i>n</i>Bu₄)N⁺, Mg²⁺, and Ca²⁺ with Guanidinium Cation in Water: Ionic Interactions from a Thermodynamic Study

Ionic interactions have been determined from the experimental osmotic coefficients, densities, and sound speeds for the mixing of guanidinium cation (Gn+) with K+, tetra-n-butylammonium cation (nBu4)N+, Mg2+, and Ca2+ in aqueous solutions containing Cl- at several ionic strengths. As Mg2+ and Ca2+ are more hydrophilic than K+, and (nBu4)N+ is a strong hydrophobic cation, their mixing with another strong hydrophobic species, that is, Gn+, throws light on the importance of binary and ternary interactions involving two cations and one common anion. The excess free energy of mixing, ΔmGE, volumes, ΔmVE, and compressibility, ΔmKE calculated from independent osmotic coefficient, density, and sound speed measurements indicate strong binary interactions as a result of mixing of K+−Gn+ and (nBu4)N+−Gn+ cation pairs. The mixing of Mg2+ with Gn+ and Ca2+ with Gn+ suggests the neutralization of opposing effects produced by the hydrophilic and hydrophobic cations. This situation, which is similar to that noted in an earlier study (Kumar, A. J. Phys. Chem. B 2000, 104, 9505) on the mixing of Na+ and Gn+, offers important information on the binary and ternary interactions present on the mixing of one hydrophilic or hydrophobic cation with another hydrophobic cationic species

Ionic Interactions from the Mixing of NaCl with the Acetate, Nitrate, Perchlorate, and Sulfate Salts of Guanidinium in Water

Ionic interactions have been investigated from the experimental isopiestic osmotic coefficient measurements on the mixing of NaCl with several guanidinium (Gn) salts, like CH3COOGn, GnNO3, GnClO4, and Gn2SO4, up to high ionic strengths. Analysis of osmotic coefficient data by the Pitzer theory offers valuable information on the mixing of ions of like and unlike charges of hydrophilic and hydrophobic nature. The mixing effects arising out of symmetrical and unsymmetrical mixing of ions are computed by the Pitzer theory in these systems. The excess Gibbs free energies of mixing, ΔmGE have been analyzed by the Friedman theory of cluster integral expansion. The ΔmGE values display very interesting features with respect to the ionic strength fraction of the acetate, nitrate, and perchlorate salts of guanidinium. The minima in the ΔmGE values are noted in the NaCl-rich mixtures, and the addition of these guanidinium salts slowly enhances ΔmGE, passing through zero to positive values. The mixing of NaCl with Gn2SO4 offers negative ΔmGE throughout the mixture composition. Although binary interactions are nearly absent in the NaCl−CH3COOGn mixtures, the ternary and quaternary interactions are noted to be important in the mixtures of NaCl with other guanidinium salts. The ΔmGE values of the mixture containing Na+, Gn+, Cl-, and SO42- ions (where binary interactions are important) can be estimated by Young's cross square rule (YCSR) with confidence. The YCSR is not obeyed when NaCl is mixed with CH3COOGn, GnNO3 and GnClO4, where ternary and quaternary interactions are dominant over the binary interactions

Homogeneous Nucleation Temperatures in Aqueous Mixed Salt Solutions

This is the first report on the measurement of homogeneous nucleation temperature, TH, in the presence of aqueous mixed salt systems of varying compositions and ionic strengths. The TH,m (TH value in aqueous mixed salt system) data for these systems have been analyzed in terms of a simple empirical equation. The TH,m values in simple aqueous mixed salts like NaCl−KCl can be approximated by linear summation of the products of ionic strength fraction and the TH values of pure salt solutions at the same ionic strength as that of the mixture. The empirical parameter, q0, indicating ionic interaction is related to the viscosity B-coefficients. The TH,m data, though correlated on the basis of the B-coefficients also depends upon the mixing of two ions of like charges. Further, a linear correlation exists between the q0 parameter and self-diffusion coefficient, D0, of the ionic solute. The q0 parameter is also well correlated with the rotational correlation time, τch/τc0 of the ionic species involved in the mixtures. It is possible to compute TH,m for the salt mixtures with no common ions from the knowledge of the TH,m values of the salt mixtures with common ions

Reassessment of the Binary, Ternary, and Quaternary Interactions in Mixed Electrolytes from Thermodynamic Quantities: The Systems with Uncommon Ions Containing Hydrophobic Character^‡

Accurate estimates of the binary, ternary, and quaternary interactions in aqueous ionic mixtures with uncommon ions with hydrophobic character are presented. For this purpose, the values of the excess Gibbs free energy of mixing, ΔmGE, obtained from our earlier isopiestic osmotic coefficients (Kumar, A. J. Phys. Chem. B 2003, 107, 2808) for the mixtures of NaCl with four guanidinium (Gn+) saltsCH3COOGn, GnNO3, GnClO4, and Gn2SO4are analyzed with the help of the method developed by Leifer and Wigent. The methodology of Leifer and Wigent is based on the equations of Scatchard−Rush−Johnson and Friedman's cluster integral expansion theory. The Scatchard−Rush−Johnson theory explicitly considers the quaternary and higher-order ionic interactions in the mixtures as compared to the specific ion interaction theory of Pitzer, which accounts for binary and ternary interactions only. The contributions due to binary, ternary, and quaternary interaction terms to total ΔmGE are estimated and discussed critically. Also, the interaction between the same two cations, for example, Gn+−Gn+, is estimated and found significant, which otherwise cannot be obtained by the use of Pitzer's theory. The information obtained from the analysis of ΔmGE is also supported by the newly measured excess volumes of mixing, ΔmVE, at 298.15 K. The individual contributions of the binary, ternary, and quaternary interaction terms to total ΔmVE are described. The binary, ternary, and quaternary interaction terms for both ΔmGE and ΔmVE are analyzed in terms of Friedman's cluster integral expansion theory

Ionic Interactions in Aqueous Mixtures of NaCl with Guanidinium Chloride: Osmotic Coefficients, Densities, Speeds of Sound, Surface Tensions, Viscosities, and the Derived Properties

The isopiestic osmotic coefficients, densities, and speeds of sound of aqueous mixtures of NaCl with guanidinium chloride (GnCl) have been measured at different ionic strengths with varying compositions at 298.15 K with a view to determine the ionic interactions. The excess free energy, ΔmGE, volume, ΔmVE, and compressibility of mixing, ΔmKE, of the NaCl−GnCl mixtures at constant ionic strength show interesting features with changing ionic strength fractions of the electrolytes. These excess properties of mixing with both negative and positive signs can be attributed to the mixing of hydrophilic and hydrophobic ions. It is shown that the binary and ternary interaction terms play an important role in the accurate representation of the osmotic coefficients, activity coefficients, volumes, and compressibilities of the mixtures. Measurements on the surface tension and viscosity of the NaCl−GnCl mixtures have also been reported. A simple equation incorporating like charge interactions has been employed to correlate the surface tension of the mixtures. The mixture viscosities have also been estimated from the parameters of pure NaCl and GnCl with an empirical mixing rule

Statistical and machine learning models for the evaluation of geophysical and geomechanical data

This thesis concerns two critical issues of modelling in geophysics. Inverse problems are ubiquitous in nature. They are often used to study a geophysical phenomenon with more than one causative set of parameters. Their mathematical formulation involves expressing them using partial differential equations. When the system is computationally extensive, it can delay the generation of solutions and the interpretation process. We understand that supervised and dimensionality reduction algorithms can help resolve such issues. We develop deep learning models for two critical applications in geophysics. We show their efficacy in speeding up the synthetic data generation process and aiding automatic interpretation.</p

Data for: Credit Constraints and GDP Growth: Evidence from a Natural Experiment

State-level panel dataset on real GDP, real GDP Growth, and other demographic characteristics from 1980 to 2007 for 50 states in the US

Synthesis and Optical Properties of Guanosine 5′-Monophosphate-Mediated CdS Nanostructures: An Analysis of their Structure, Morphology, and Electronic Properties

The present manuscript reports the synthesis, characterization, and analysis of electronic properties of water-soluble guanosine 5′-monophosphate (GMP)-mediated CdS quantum dots (Q-dots). The morphology, size, and size distribution of these particles have been analyzed by transmission electron microscopy. These particles display the onset of absorption at 2.7 eV and emission at 2.2 eV. In comparison to other monophosphates of RNA (AMP, UMP, and CMP), GMP-mediated CdS exhibits enhanced electronic properties. The participation of different functional groups of GMP in the stabilization of CdS nanoparticles has been analyzed by FTIR and 1H and 31P NMR spectroscopic techniques. Two types of binding sites involving phosphorus centers are indicated by IR and 31P NMR studies. The conversion of CdS Q-dots to nanorods has been monitored by using electron microscopy, steady-state optical and fluorescence measurements, and a fluorescence lifetime system coupled with anisotropy accessories. The observed change in the morphology and electronic behavior of GMP- and RNA-mediated CdS nanostructures is discussed on the basis of their structural difference

Self-Assemblies from RNA-Templated Colloidal CdS Nanostructures

RNA serves as an effective template for the synthesis of quantized CdS nanoparticles and mediates their growth to create novel assemblies. Unlike DNA-stabilized particles in aqueous medium, these particles display relatively strong emission at 2.34 eV, which is further enhanced by more than 2.5 fold and blue shifts to higher energy (2.39 eV) upon aging. Chelation of Cd2+ with RNA restricts the nucleation of CdS. A variation in the molar ratio of Cd/S from 2 to 6 produces different nanostructures with varied electronic properties. Unlike general colloidal systems, aging of these nanoparticles produced smaller crystalline nanocrystals as evidenced by their blue-shifted optical threshold and fluorescence maxima, and by atomic force microscopy and transmission electron microscopy analysis. Different nanostructures grow upon aging to yield self-assembly of different shapes, and the morphology and structure of these nanostructures could be manipulated by changing the molar ratio of Cd/S. The formation of organized structures could provide a basis for controlled fabrication of new nanostructures and nanodevices