Active Fluidization Storage Applications for CSP

AbstractThe current paper proposes three thermal storage concepts for solar thermal power plants, which are all based on sand powder as storage medium. The solid powder is used in a manner similar to fluid storage media such as molten salt. Fluidization is needed in order to produce fluid-like behavior of the powder. Applying powders as storage media for thermal energy storages offers advantages such as low cost, no freezing danger and hence no melting effort, no corrosion, local availability and high allowable temperatures. The storage media demand for all three concepts is estimated

Incorporating ‘Company Reputation’ into Total Enterprise Simulations

The literature on simulation and gaming has done very little to address emerging concepts such as relationship marketing, brand equity, and company reputation. This paper relates these to each other, linking them to a new business paradigm, in which companies seek to harness the long-term value of reputation and relationships to lower transaction costs with key stakeholders. It then presents a model for incorporating the concept of company reputation into a total enterprise simulation. It builds on an empirically derived model of company reputation in which various company characteristics are linked to two underlying dimensions of reputation: sympathy and competence. The paper suggests how the various components of company reputation might be operationalized in a simulation game. It then discusses how they might be used to both help determine and evaluate student performance

What’s important for relationship management? The mediating roles of relational trust and satisfaction for loyalty of cooperative banks’ customers

Building on the corporate reputation model, this study investigates the drivers of customer-based corporate reputation. We consider two corporate reputation dimensions (i.e., the cognitive dimension competence and the affective dimension likeability, and their effects on customer satisfaction and loyalty). Adapting the model to the banking sector, we theoretically extend this model by reasoning that customer satisfaction and relational trust are mediators of the relationship between the two corporate reputation dimensions and loyalty. Studying a sample of 675 customers and members of cooperative banks in Germany, we find perceived attractiveness to be the most important driver of corporate reputation. Furthermore, we confirm a positive relationship between corporate reputation and loyalty, and a mediating effect of both satisfaction and relational trust. With our study, we give support for the proposition of customer satisfaction's as well as relational trust’s role as mediators of the relationship between corporate reputation and loyalty. With this research, we expand our knowledge on the well-known corporate reputation model, which has high relevance and important implications for marketing research and relationship management practice

How Tribo-Oxidation Alters the Tribological Properties of Copper and Its Oxides

Tribochemical reactions in many applications determine the performance and lifetime of individual parts or entire engineering systems. The underlying processes are however not yet fully understood. Here, the tribological properties of copper and its oxides are investigated under mild tribological loading and for dry sliding. The oxides represent the late stages of a copper–sapphire tribo‐contact, once the whole copper surface is covered with an oxide. For this purpose, high‐purity copper, thermally‐oxidized and sintered Cu$_{2}$O and CuO samples are tribologically loaded and eventually formed wear particles analyzed. The tribological behavior of the oxides is found to be beneficial for a reduction of the coefficient of friction (COF), mainly due to an increase in hardness. The results reveal tribochemical reactions when copper oxides are present, irrespective of whether they form during sliding or are existent from the beginning. Most strikingly, a reduction of copper oxide to metallic copper is observed in X‐ray photoelectron spectroscopy measurements. A more accurate understanding of tribo‐oxidation will allow for manufacturing well‐defined surfaces with enhanced tribological properties. This paves the way for extending the lifetime of contacts evincing tribo‐oxidation

The indentation size effect of single-crystalline tungsten revisited

In this study, we have investigated the indentation size effect (ISE) of single crystalline tungsten with low defect density. As expected, the hardness shows a pronounced increase with decreasing indentation depth as well as a strong strain rate dependence. For penetration depths greater than about 300 nm, the ISE is well captured by the Nix–Gao model in the context of geometrically necessary dislocations. However, clear deviations from the model are observed in the low depth regime resulting in a bilinear effect. The hardness behavior in the low depth regime can be modeled assuming a non-uniform spacing of the geometrically necessary dislocations. We propose that the bilinear indentation size effect observed reflects the evolution of the geometrically necessary dislocation density. With increasing strain rate, the bilinear effect becomes less pronounced. This observation can be rationalized by the activation of different slip systems

How Tribo-Oxidation Alters the Tribological Properties of Copper and Its Oxides

Tribochemical reactions in many applications determine the performance and lifetime of individual parts or entire engineering systems. The underlying processes are however not yet fully understood. Here, the tribological properties of copper and its oxides are investigated under mild tribological loading and for dry sliding. The oxides represent the late stages of a copper–sapphire tribo‐contact, once the whole copper surface is covered with an oxide. For this purpose, high‐purity copper, thermally‐oxidized and sintered Cu$_{2}$O and CuO samples are tribologically loaded and eventually formed wear particles analyzed. The tribological behavior of the oxides is found to be beneficial for a reduction of the coefficient of friction (COF), mainly due to an increase in hardness. The results reveal tribochemical reactions when copper oxides are present, irrespective of whether they form during sliding or are existent from the beginning. Most strikingly, a reduction of copper oxide to metallic copper is observed in X‐ray photoelectron spectroscopy measurements. A more accurate understanding of tribo‐oxidation will allow for manufacturing well‐defined surfaces with enhanced tribological properties. This paves the way for extending the lifetime of contacts evincing tribo‐oxidation