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Bei der Auswertung seiner vor Sylt durchgeführten Naturmessungen hochenergetischer Brandungswellen war der Autor auf das bis dahin für Schwerewellen unbekannte Phänomen der anomalen Dispersion gestoßen. Unter Dispersion wird bei den meisten Wellenarten insbesondere die Abhängigkeit der Phasengeschwindigkeit (Wellenfortschrittsgeschwindigkeit) c[m/s] von der Frequenz f[Hz] bzw. von der Wellenlänge L[m] verstanden. Bei Schwerewellen ist diese normal und durch dc/df ≤ 0 bzw. dc/dL ≥ 0 gekennzeichnet, etwa vergleichbar den elektromagnetischen Wellen (EM-Wellen) im Bereich des sichtbaren Lichts mit der bekannten Abfolge der Spektralfarben. Resonanzen treten aber insbesondere auch bei EM-Wellen zusammen mit dem Phänomen der anomalen Dispersion mit dc/df > 0 bzw dc/dL < 0 auf. Als Ergebnis der Suche nach analogen Bedingungen bei Wasserwellen hat der Autor insbesondere zwei unterschiedliche Modellvorstellungen für (partiell) stehende Wellen im Zusammenhang mit resonanten Beckenschwingungen als anwendbar erkannt: In der Natur als Resonanz der von See kommenden Wellen (Erreger) mit partiell stehenden Halbwellen in einem abgrenzbaren Beckenvolumen (Resonator) und im verkleinerten Modell als Resonanz des Wellenerzeugers (Erreger) mit partiell stehenden Viertelwellen im Wellenkanal (Resonator). Analyzing field measurements of high energetic surf waves, the author has come across an anomalous dispersion effect (ADE) that was previously unknown in connection with gravity waves. For most kinds of waves, dispersion means the dependence of phase velocity c[m/s] on frequency f[Hz] or on wave length [L] respectively. With gravity waves dispersion is normal, which means that dc/df ≤ 0 or dc/dL ≥ 0, - similar to what is known about electromagnetic waves (EM-waves) in the limited frequency range of the visible light (as demonstrated by the known sequence of spectral colors). With EM-waves, however, Resonances appear together with the phenomenon of an ADE, marked by dc/df > 0 or dc/dL < 0 respectively. Seeking analogue conditions for water waves, the author had found two different model conceptions to be appropriate for (partial) standing waves in connection with basin oscillations. In natural field conditions: incident waves from the sea (stimulator) resonating with partial standing half-waves in a definable water basin (resonator), and in a scale model: the wave maker (stimulator) resonating with partial standing quarter-waves in the wave tank (resonator).

Thermochemical multistep processes are promising options to face future energy problems. Such reactions can be used to enhance the availability of solar energy in terms of energy transport, of energy demand/supply management and of potential energy related applications. Coupling concentrated sunlight to suitable sequences of thermochemical reaction enables the production of hydrogen, syngas and other fuels derived from those precursors by water- and CO2-splitting as well as the storage of solar energy by breaking and forming chemical bonds in suitable reversible reactions. These processes are sustainable and environmentally attractive since only water, CO2 and solar power are used as “raw materials”. All other materials involved are recycled within the process. The concentrated solar energy is converted into storable and transportable chemicals and fuels. One of the major barriers to technological success of many of those processes is the identification of suitable active materials like catalysts and redox materials exhibiting satisfactory durability, reactivity and efficiencies. Moreover, materials play an important role in the construction of key components of the respective high-temperature processes and for the implementation in commercial solar plants. Besides materials aspects also process engineering issues needs to be overcome. One of the most striking challenges is to couple an intermittent energy source to a chemical process. The most promising thermochemical processes are being described and discussed with respect to further development and future potential. The main challenges of those processes are being analyzed. Technical approaches and development progress in terms of solving them are addressed and assessed.