Technical University of Berlin

About: Technical University of Berlin is a education organization based out in Berlin, Germany. It is known for research contribution in the topics: Quantum dot & Laser. The organization has 27292 authors who have published 59342 publications receiving 1414623 citations. The organization is also known as: Technische Universität Berlin & TU Berlin.

The Fischer-Tropsch Synthesis in the Liquid Phase

Abstract: The hydrogenation of carbon monoxide by the Fischer-Tropsch (F-T) process [1] forms saturated and unsaturated compounds of the homologous hydrocarbon series. It permits the synthesis of hydrocarbons ranging from methane to high-melting paraffins with molecular weights above 20,000, depending on the catalyst, temperature, and type of process employed. By-products such as alcohols, aldehydes, ketones, acids, and esters are formed on a smaller scale. Small amounts of aromatic compounds are formed at high temperatures by secondary dehydrocyclization reactions from the primary hydrocarbons formed.

Effects of pulsed electric fields on bioactive compounds in foods: a review

Abstract: Pulsed electric fields have the potential to be used as alternative to other conventional techniques of food production. In the last few years, several studies have demonstrated the ability of intense treatments to obtain safe and shelf-stable liquid foods. On the other hand, novel applications such as improvement of mass transfer processes or generation of bioactive compounds by using moderate field strengths are under current development. However, the effects of pulsed electric field treatments on minor constituents of foods, namely on bioactive compounds, have not been always considered. This review aims at updating the state of the art regarding the impact of pulsed electric field processing conditions on the stability of bioactive compounds in food systems.

Metal Foams: Production and Stability†

Abstract: Liquid metal foam can be generated by creating gas inside a liquid or semi-liquid metallic melt which has been pre-treated in a suitable way. Such foams are self-supporting disordered structures in complete analogy to aqueous foams. The stabilisation mechanism of metallic foams is still not fully understood. In order to facilitate discussion of foam stabilisation the various methods for making such foams are classified with respect to the mode of gas generation and the type of melt used for foaming. Metal foams can be produced by gas injection from an external source or by in-situ nucleation of gas bubbles in the melt for which various possibilities are known. Melts amenable to foaming range from almost pure molten alloys to melts to which particles have been added, formed by in-situ reactions or which have been already present in the solid precursor prior to melting. Some of the available experimental evidence for the action of stabilising particles in metallic foams is presented. It is found that although stabilisation seems to be based on the presence of a solid constituent in all the foaming processes, the mechanisms might vary. At present the nature of stabilisation is not yet fully understood and many questions remain

Role-based multicast in highly mobile but sparsely connected ad hoc networks

Abstract: We present an approach to multicasting messages among highly mobile hosts in ad hoc networks. We suggest a new definition of a role-based multicast that suits the special needs of inter-vehicle communication: rather than by explicit identification, a multicast group is defined implicitly by location, speed, driving direction and time. As an example, we study a road accident that is reported to nearby vehicles. We focus on sparse deployment of the system which is likely to occur soon after the system is introduced to the market. In this state, the resulting ad hoc network tends to be disconnected. We tailor the proposed algorithm to overcome this problem of network fragmentation. Simulations show us the quality of the proposed protocol by measuring how many vehicles inside a multicast area are informed in time under various conditions.