Most minerals and concentrates, auxiliaries, agricultural and synthetic particulate solid products are produced with particle sizes of less than 100 lm. These fine powders show similar problematic product properties. Their interparticle adhesion forces, especially van der Waals forces, exceed the gravitational forces by orders of magnitude. Thus, the trouble-free treatment of these products presents large problems as well as scientific and technological challenges. The physical properties of such materials, especially flowability, are essential for many industrial applications including product generation, processing, application and consumption, e.g., in the pharmaceutical, chemical, food and manufacturing industries or plant engineering. In recent decades, one of the most frequently used solutions to this problem has been to add small amounts of flow additives that improve the flowability of these fine cohesive powders. This paper provides an overview of the physico-chemically active principles of flow additives, model approaches and useful flowability evaluation methods. The efficiency of several flow additives, i.e., nanoparticles and surfactants, is critically discussed by the provision of selected test results from the literature. Conclusions are drawn with respect to the application of this flow additive method in process industries. Introduction and Problem DescriptionThere are many branches of the global economy, in which particulate solids, i.e., bulk solids and powders, are produced, transported, handled, converted or consumed. This include collections of particle of all sizes, usually classified as bulk solids (d > 100 lm), as well as fine (d < 100 lm), ultrafine (d < 10 lm) and nanoscale (d < 100 nm) powders 1) . Frequently, the term "bulk solids" is also used for all heaped particle collectives independent of particle sizes.Many raw materials, additives, agricultural and synthetic particulate solids are produced with particle sizes smaller than 100 lm. These materials show a number of problematic product properties [1]. Their interparticle forces, especially van der Waals forces, exceed the gravitational forces by several orders of magnitude. Thus, the trouble-free handling of these products is a serious problem as well as presenting a scientific and technological challenge. However, their physical properties, especially the flowability, are essential in several industrial applications, e.g., in the pharmaceutical, food, and chemical industries as well as in mechanical and plant engineering.Flowing or yielding means that a powder is brought to irreversible deformation, and therefore, to the desired level of flow by an external mechanical stressing event which can be a force or energy. According to this method, only the trouble-free discharge of a powder out off a storage container by its dead weight is considered as good flowability. In contrast, powders that show flow problems are classified as poorly flowing or non-flowing. Such flow problems are very frequent in the case of cohesive powders with...

The investigation of different selective emitter (SE) approaches [1-3] is a current trend in solar cell manufacturing. The incorporation of a local high phosphorous doping underneath the front contact grid allows for the use of high-sheet resistance illuminated emitters that combine low recombination and improved blue response. Further efficiency increase compared to the standard screen-printed solar cell is achieved via plated contacts [4-5] that feature better aspect ratio and optical properties [6], higher line conductivity and smaller width [5] compared to screen-printed contacts. In this paper we present detailed technological requirements for next-generation front side metallization as well as experimental results of the RENA high-efficiency metallization cluster consisting of Laser Chemical Processing (LCP) and Ni-Ag light-induced plating (LIP). It becomes clear that efficiency on cell level is not the only figure of merit for a successful product and that the co mbination of SE with plating has a much higher potential for increasing cell efficiency than the metallization of SE via screen-printing

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L’article explore la pluralité des lieux dans l’œuvre poétique de l’écrivain dans leur rapport à l’acoustique, tant l’écoute que la parole proférée. Les paysages, qu’ils soient ruraux, citadins, provinciaux, domestiques ou publics, confèrent aux textes leur substance spatiale. Quant à la dimension sonore, elle ressortit à la perception (les voix, les bruits, produits par les humains, les autres êtres vivants, les choses) tout autant qu’au soliloque du Je poétique. Entendre les lieux et tout ce qui les peuple implique enfin une plongée dans le temps, le poème s’avère être alors îlot de souvenir extrait de l’oubli.