92 research outputs found
Improved biological methanation using tubular foam-bed reactor
No full textKhesali Aghtaei H, Heyer R, Reichl U, Benndorf D. Improved biological methanation using tubular foam-bed reactor. Biotechnology for Biofuels and Bioproducts . 2024;17(1): 66.BACKGROUND: Power-to-gas is the pivotal link between electricity and gas infrastructure, enabling the broader integration of renewable energy. Yet, enhancements are necessary for its full potential. In the biomethanation process, transferring H2 into the liquid phase is a rate-limiting step. To address this, we developed a novel tubular foam-bed reactor (TFBR) and investigated its performance at laboratory scale.; RESULTS: A non-ionic polymeric surfactant (Pluronic F-68) at 1.5% w/v was added to the TFBR's culture medium to generate a stabilized liquid foam structure. This increased both the gas-liquid surface area and the bubble retention time. Within the tubing, cells predominantly traveled evenly suspended in the liquid phase or were entrapped in the thin liquid film of bubbles flowing inside the tube. Phase (I) of the experiment focused primarily on mesophilic (40°C) operation of the tubular reactor, followed by phase (II), when Pluronic F-68 was added. In phase (II), the TFBR exhibited 6.5-fold increase in biomethane production rate (MPR)to 15.1 ( L CH 4 /L R /d) , witha CH4 concentration exceeding 90% (grid quality), suggesting improved H2 transfer. Transitioning to phase (III) with continuous operation at 55°C, the MPR reached 29.7 L CH 4 /L R /d while maintaining the grid quality CH4. Despite, reduced gas-liquid solubility and gas-liquid mass transfer at higher temperatures, the twofold increase in MPR compared to phase (II) might be attributed to other factors, i.e., higher metabolic activity of the methanogenic archaea. To assess process robustness for phase (II) conditions, a partial H2 feeding regime (12h 100% and 12h 10% of the nominal feeding rate) was implemented. Results demonstrated a resilient MPR of approximately 14.8 L CH 4 /L R /d even with intermittent, low H2 concentration.; CONCLUSIONS: Overall, the TFBR's performance plant sets the course for an accelerated introduction of biomethanation technology for the storage of volatile renewable energy. Robust process performance, even under H2 starvation, underscores its reliability. Further steps towards an optimum operation regime and scale-up should be initiated. Additionally, the use of TFBR systems should be considered for biotechnological processes in which gas-liquid mass transfer is a limiting factor for achieving higher reaction rates. © 2024. The Author(s)
Explorative study into the sustainable use and substitution of soldering metals in electronics: Ecological and economical consequences of the ban of lead in electronics and lessons to be learned for the future
No full textThe Directive 2002/95/EC (RoHS Directive), among other substances, bans the use of lead in the electrical and electronics industry. This explorative study assesses the worldwide environmental and economical effects of the substitution of lead in solders and finishes. It shows the worldwide additional cost of lead-free soldering compared to soldering with lead-containing solders and finishes. Also the additional consumption of tin, silver, bismuth and other metals, the worldwide additional energy consumption has been studied in detail. A third main subject addressed is how lead-free soldering changes the potential toxicity and the risk of hazardous impacts from waste of electrical and electronics equipment (WEEE). The methodical framework developed enables evaluating the environmental and economical impacts from the three perspectives of sustainable development: efficiency, consistency and sufficiency. In these three domains, a comparison was made between lead-free and soldering with lead-containing solders and finishes. The study develops recommendations for the stakeholders in the manufacturing industry, recyclers and governments on the proper implementation of lead-free soldering. Finally, this work presents the knowledge and the methodical basis for governments to enable decisions on restrictions of hazardous materials that contribute to sustainable development.Industrial Design Engineerin
The transition to chaos: conservative classical systems and quantum manifestations
No full textThis book provides a thorough and comprehensive discussion of classical and quantum chaos theory for bounded systems and for scattering processes Specific discussions include • Noether’s theorem, integrability, KAM theory, and a definition of chaotic behavior • Area-preserving maps, quantum billiards, semiclassical quantization, chaotic scattering, scaling in classical and quantum dynamics, dynamic localization, dynamic tunneling, effects of chaos in periodically driven systems and stochastic systems • Random matrix theory and supersymmetry The book is divided into several parts Chapters 2 through 4 deal with the dynamics of nonlinear conservative classical systems Chapter 5 and several appendices give a thorough grounding in random matrix theory and supersymmetry techniques Chapters 6 and 7 discuss the manifestations of chaos in bounded quantum systems and open quantum systems respectively Chapter 8 focuses on the semiclassical description of quantum systems with underlying classical chaos, and Chapter 9 discusses the quantum mechanics of systems driven by time-periodic forces Chapter 10 reviews some recent work on the stochastic manifestations of chaos The presentation is complete and self-contained; appendices provide much of the needed mathematical background, and there are extensive references to the current literature End of chapter problems help students clarify their understanding In this new edition, the presentation has been brought up to date throughout, and a new chapter on open quantum systems has been added About the author Linda E Reichl, PhD, is a Professor of Physics at the University of Texas at Austin and has served as Acting Director of the Ilya Prigogine Center for Statistical Mechanics and Complex Systems since 1974 She is a Fellow of the American Physical Society and currently is US Editor of the journal Chaos, Solitons, and Fractal
EVOLUTION OF A METALLIC AND MAGNETIC STATE IN (Fe, Mn)Si AND Fe(Si, Ge)
No full textAn analysis of the pressure-dependent resistivity of FexMn1-xSi(1 less than or equal to x less than or equal to 0.82) and FeSixGe1-x (1 less than or equal to x less than or equal to 0.6) alloys in terms of a Kondo insulator description revealed a pressure-induced opening of the narrow gap. A negative magnetoresistance is observed for Fe-rich alloys of FexMn1-xSi at elevated temperatures
Whips and chains excite me: BDSM, social acceptance, and the sexual double standard
No full textThis study examined the social acceptance of Dominant/submissive relationships when gender of the Dominant and exposure to normalizing information were manipulated. A sadomasochism attitudes scale was used to gather opinions about BDSM relationships. Results partially supported hypotheses; female participants reported greater social acceptance for female Dominants when provided with normative information about the couple.Poster presented at the annual meeting of the Association for Psychological Science, San Francisco, CA, 201
Comparing wave and stirred-tank bioreactor performance for vaccine production with feline lung fibroblasts
No full textSince several years the adherent cell line E-FL (feline lung fibroblast) is used for production of mink enteritis virus (MEV) vaccine at commercial scale. Presently the industrial process is performed in roller bottles. For large-scale production this approach means high input of equipment and manpower connected with a comparatively high contamination risk. Additionally, monitoring and control of cultivation conditions is very limited compared to fully equipped bioreactors. Aim of our research project was the transfer of the existing production process from roller bottles into a microcarrier system (Cytodex 1) and the optimization with respect to virus yields. First experiments for characterization of growth and metabolism of E-FL on Cytodex 1 were carried out in spinner flask (250 mL-scale) using a minimal essential medium (MEM) with fetal bovine serum (FBS) and L-glutamine. Standard analytics included measurement of cell number, pH, pO2 and extracellular metabolites (glucose, lactate, glutamine, glutamate, ammonia). As these first experiments were successful, the process was scaled up into a 5 L stirred-tank reactor using 1 g/L Cytodex 1 and a starting cell number of 0,6-1105 cells/mL. After three days of cultivation confluence was reached with cell numbers of 7-9105 cells/mL. Using higher carrier concentrations and improved MEM the cell yield could even be increased to 1,5-2106 cells/mL. Alternatively, cultivation of E-FL on Cytodex 1 in a novel wave bioreactor was established. Advantages of this system are low costs and its safety and simplicity in use under GMP restrictions. Cultivations of E-FL in the wave bioreactor were as successful as in stirred-tanks regarding cell numbers, morphology and metabolic activities. Optimal parameters for virus propagation were investigated by parallel cultivation in small scale fermenters (500 mL) using different MOI and starting cell numbers. Based on these results further experiments for virus propagation in stirred-tank-(5 L-scale) and wave bioreactor (1 L-scale) were carried out. Both culture vessels are compared with respect to cell growth and virus yields. We are able to show that both types of bioreactors are suitable for use in MEV vaccine production process. It is expected that slight advantages of stirred tank in cell number are more than balanced by low costs and simple GMP-conform handling of the wave bioreactor
Wimsatt, James I.: Chaucer and the Poems of 'Ch' in University of Pennsylvania MS French 15
No full textCoherent spin-exchange via a quantum mediator
No full textCoherent interactions at a distance provide a powerful tool for quantum simulation and computation. The most common approach to realize an effective long-distance coupling on-chip' is to use a quantum mediator, as has been demonstrated for superconducting qubits and trapped ions. For quantum dot arrays, which combine a high degree of tunability with extremely long coherence times, the experimental demonstration of the time evolution of coherent spin-spin coupling via an intermediary system remains an important outstanding goal. Here, we use a linear triple-quantum-dot array to demonstrate a coherent time evolution of two interacting distant spins via a quantum mediator. The two outer dots are occupied with a single electron spin each, and the spins experience a superexchange interaction through the empty middle dot, which acts as mediator. Using single-shot spin readout, we measure the coherent time evolution of the spin states on the outer dots and observe a characteristic dependence of the exchange frequency as a function of the detuning between the middle and outer dots. This approach may provide a new route for scaling up spin qubit circuits using quantum dots, and aid in the simulation of materials and molecules with non-nearest-neighbour couplings such as MnO (ref. 27), high-temperature superconductors and DNA. The same superexchange concept can also be applied in cold atom experiments.Accepted Author ManuscriptQCD/Vandersypen La
Die Technologische Akzeptanz von digitalen Mietverträgen bei österreichischen Mietern
No full textAuthor Johannes ReichlAbweichender Titel laut Übersetzung der Verfasserin/des VerfassersMasterarbeit Johannes Kepler Universität Linz 2025Arbeit nach Ablauf der Sperre auf den öffentlichen PCs in den Bibliotheken der JKU+Medizin abrufba
Die Technologische Akzeptanz von digitalen Mietverträgen bei österreichischen Mietern
No full textAuthor Johannes ReichlAbweichender Titel laut Übersetzung der Verfasserin/des VerfassersMasterarbeit Johannes Kepler Universität Linz 2025Arbeit nach Ablauf der Sperre auf den öffentlichen PCs in den Bibliotheken der JKU+Medizin abrufba
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