Studies of the aerobic treatment of digestate in the liquid Phase

Aufgrund der in Deutschland geltenden gesetzlichen Grenzwerte zur Ablagerung behandelten Abfalls ist nach derzeitigem Kenntnisstand eine aerobe Nachbehandlung des Gärrestes zur Stabilisierung notwendig. Als Alternative zur konventionellen Stabilisierung der getrockneten Gärrückstände kann in Anlehnung des Prinzips eines Belebungsbeckens der Abwasserbehandlung im Anschluss an die Nassvergärung die aerobe Nachbehandlung in der Flüssigphase erfolgen. Eine Bewertung hinsichtlich Energieeffizienz und Leistungsfähigkeit ist bisher nicht erfolgt. Hier knüpfen die Untersuchungen der vorliegenden Arbeit an. Im Fokus standen die Beurteilung der Abbauleistung relevanter Summenparameter (CSB, TOC, oTS, BSB5) in Abhängigkeit der Belüftungsintensität, sowie ergänzende Untersuchungen zur Sauerstoffversorgung und Nitrifikation. Hierzu wurden Versuchsvarinaten im Labormaßstab und im technischen Maßstab durchgeführt. Schließlich erfolgte eine Bewertung der Prozessstufe Aerobisierung unter Einbezug konventioneller Behandlungstechniken (intensive Kompostierungssysteme) und die Ableitung von Optimierungsmaßnahmen einer bestehenden Prozessstufe. Als wesentliches Ergebnis dieser Arbeit bleibt festzuhalten, dass die aerobe Nachbehandlung von Gärresten in der flüssigen Phase bezüglich der Abbauleistung und der Behandlungszeit konventionellen Nachbehandlungsverfahren mindestens gleichzusetzen ist. Die Energieeffizienz hingegen ist mit entsprechenden Maßnahmen deutlich zu steigern, hier besteht Forschungspotenzial.Due to the fact that the criteria of the relevant parameters of the waste disposal order in Germany are very strict an aftertreatment process is needed to comply. As an alternative to the conventional stabilizing processes like rotting the dried digestate it is possible aerating and stirring the wet digestate in the liquid phase. The process is realized in accordance of the principle of an aeration basin known from the waste water treatment. An assessment of energy efficiency and performance of the process has not been done yet. This results in a high research potential and forms the basis of the investigations of the present work. The focus was on the assessment of the degradation capacity of relevant sum parameters (COD, TOC, oDS, BOD5) as a function of ventilation rate, as well as additional studies on the oxygenation and nitrification. For this purpose, experiments were conducted in the laboratory and on an industrial scale. Finally, an estimation of the level of aeration process with the involvement of conventional treatment techniques (intensive composting systems) is carried out. Based on the results of the experiments optimization potential of an existing process stage is derived. As main result of this work it can be concluded that the aerobic treatment of digestate in the liquid phase with respect to the degradation rate and the treatment time is equivalent to the conventional treatment method at least. However, the energy efficiency is increasing significantly with appropriate measures. In this context research potential in the future consists

Turbulent Micropolar SPH Fluids with Foam

In this paper we introduce a novel micropolar material model for the simulation of turbulent inviscid fluids. The governing equations are solved by using the concept of Smoothed Particle Hydrodynamics (SPH). SPH fluid simulations suffer from numerical diffusion which leads to a lower vorticity, a loss in turbulent details and finally in less realistic results. To solve this problem we propose a micropolar fluid model. The micropolar fluid model is a generalization of the classical Navier-Stokes equations, which are typically used in computer graphics to simulate fluids. In contrast to the classical Navier-Stokes model, micropolar fluids have a microstructure and therefore consider the rotational motion of fluid particles. In addition to the linear velocity field these fluids have a field of microrotation which represents existing vortices and provides a source for new ones. Our novel micropolar model can generate realistic turbulences, is linear and angular momentum conserving, can be easily integrated in existing SPH simulation methods and its computational overhead is negligible. Another important visual feature of turbulent liquids is foam. Therefore, we present a post-processing method which considers microrotation in the foam generation. It works completely automatic and requires only one user-defined parameter to control the amount of foam

A Multi-scale Model for Simulating Liquid-hair Interactions

© ACM, 2017. This is the author's version of the work. It is posted here by permission of ACM for your personal use. Not for redistribution. The definitive version was published in Fei, Y. (Raymond), Maia, H. T., Batty, C., Zheng, C., & Grinspun, E. (2017). A Multi-scale Model for Simulating Liquid-hair Interactions. ACM Trans. Graph., 36(4), 56:1–56:17. https://doi.org/10.1145/3072959.3073630The diverse interactions between hair and liquid are complex and span multiple length scales, yet are central to the appearance of humans and animals in many situations. We therefore propose a novel multi-component simulation framework that treats many of the key physical mechanisms governing the dynamics of wet hair. The foundations of our approach are a discrete rod model for hair and a particle-in-cell model for fluids. To treat the thin layer of liquid that clings to the hair, we augment each hair strand with a height field representation. Our contribution is to develop the necessary physical and numerical models to evolve this new system and the interactions among its components. We develop a new reduced-dimensional liquid model to solve the motion of the liquid along the length of each hair, while accounting for its moving reference frame and influence on the hair dynamics. We derive a faithful model for surface tension-induced cohesion effects between adjacent hairs, based on the geometry of the liquid bridges that connect them. We adopt an empirically-validated drag model to treat the effects of coarse-scale interactions between hair and surrounding fluid, and propose new volume-conserving dripping and absorption strategies to transfer liquid between the reduced and particle-in-cell liquid representations. The synthesis of these techniques yields an effective wet hair simulator, which we use to animate hair flipping, an animal shaking itself dry, a spinning car wash roller brush dunked in liquid, and intricate hair coalescence effects, among several additional scenarios.Graduate Student Research FellowshipNational Science FoundationNatural Sciences and Engineering Research Council of Canad

Differential Loss and Retention of Cytoglobin, Myoglobin, and Globin-E during the Radiation of Vertebrates

If rates of postduplication gene retention are positively correlated with levels of functional constraint, then gene duplicates that have been retained in a restricted number of taxonomic lineages would be expected to exhibit relatively low levels of sequence conservation. Paradoxical patterns are presented by gene duplicates that have been retained in a small number of taxa but which are nonetheless subject to strong purifying selection relative to paralogous members of the same multigene family. This pattern suggests that such genes may have been co-opted for novel, lineage-specific functions. One possible example involves the enigmatic globin-E gene (GbE), which appears to be exclusively restricted to birds. Available data indicate that this gene is expressed exclusively in the avian eye, but its physiological function remains a mystery. In contrast to the highly restricted phyletic distribution of GbE, the overwhelming majority of jawed vertebrates (gnathostomes) possess copies of the related cytoglobin (Cygb) and myoglobin (Mb) genes. The purpose of the present study was 1) to assess the phyletic distribution of the Cygb, Mb, and GbE genes among vertebrates, 2) to elucidate the duplicative origins and evolutionary histories of these three genes, and 3) to evaluate the relative levels of functional constraint of these genes based on comparative sequence analysis. To accomplish these objectives, we conducted a combined phylogenetic and comparative genomic analysis involving taxa that represent each of the major lineages of gnathostome vertebrates. Results of synteny comparisons and phylogenetic topology tests revealed that GbE is clearly not the product of a recent, bird-specific duplication event. Instead, GbE originated via duplication of a proto-Mb gene in the stem lineage of gnathostomes. Unlike the Mb gene, which has been retained in all major gnathostome lineages other than amphibians, the GbE gene has been retained only in the lineage leading to modern birds and has been independently lost in at least four major lineages: teleost fish, amphibians, mammals, and nonavian reptiles. Despite the restricted phyletic distribution of this gene, our results indicate that GbE is one of the most highly conserved globins in the avian genome

A Membrane-Bound Vertebrate Globin

The family of vertebrate globins includes hemoglobin, myoglobin, and other O2-binding proteins of yet unclear functions. Among these, globin X is restricted to fish and amphibians. Zebrafish (Danio rerio) globin X is expressed at low levels in neurons of the central nervous system and appears to be associated with the sensory system. The protein harbors a unique N-terminal extension with putative N-myristoylation and S-palmitoylation sites, suggesting membrane-association. Intracellular localization and transport of globin X was studied in 3T3 cells employing green fluorescence protein fusion constructs. Both myristoylation and palmitoylation sites are required for correct targeting and membrane localization of globin X. To the best of our knowledge, this is the first time that a vertebrate globin has been identified as component of the cell membrane. Globin X has a hexacoordinate binding scheme and displays cooperative O2 binding with a variable affinity (P50∼1.3–12.5 torr), depending on buffer conditions. A respiratory function of globin X is unlikely, but analogous to some prokaryotic membrane-globins it may either protect the lipids in cell membrane from oxidation or may act as a redox-sensing or signaling protein

Phylogeny of Echinoderm Hemoglobins

Recent genomic information has revealed that neuroglobin and cytoglobin are the two principal lineages of vertebrate hemoglobins, with the latter encompassing the familiar myoglobin and α-globin/β-globin tetramer hemoglobin, and several minor groups. In contrast, very little is known about hemoglobins in echinoderms, a phylum of exclusively marine organisms closely related to vertebrates, beyond the presence of coelomic hemoglobins in sea cucumbers and brittle stars. We identified about 50 hemoglobins in sea urchin, starfish and sea cucumber genomes and transcriptomes, and used Bayesian inference to carry out a molecular phylogenetic analysis of their relationship to vertebrate sequences, specifically, to assess the hypothesis that the neuroglobin and cytoglobin lineages are also present in echinoderms.The genome of the sea urchin Strongylocentrotus purpuratus encodes several hemoglobins, including a unique chimeric 14-domain globin, 2 androglobin isoforms and a unique single androglobin domain protein. Other strongylocentrotid genomes appear to have similar repertoires of globin genes. We carried out molecular phylogenetic analyses of 52 hemoglobins identified in sea urchin, brittle star and sea cucumber genomes and transcriptomes, using different multiple sequence alignment methods coupled with Bayesian and maximum likelihood approaches. The results demonstrate that there are two major globin lineages in echinoderms, which are related to the vertebrate neuroglobin and cytoglobin lineages. Furthermore, the brittle star and sea cucumber coelomic hemoglobins appear to have evolved independently from the cytoglobin lineage, similar to the evolution of erythroid oxygen binding globins in cyclostomes and vertebrates.The presence of echinoderm globins related to the vertebrate neuroglobin and cytoglobin lineages suggests that the split between neuroglobins and cytoglobins occurred in the deuterostome ancestor shared by echinoderms and vertebrates

Charakterisierung der biologischen Funktion der Plasmodium falciparum Calcium-abhängigen Proteinkinase 1

Im Rahmen dieser Arbeit wurden biologische Funktionen einer Proteinkinase des Erregers der Malaria tropica, genauer der „Plasmodium falciparum calcium dependent protein kinase 1“ (PfCDPK1), in parasitären Blutstadien untersucht.rnUm Einblicke in die Funktion der Kinase, die sie in den extrazellulären Kompartimenten des Parasiten übernimmt, zu gewinnen, wurden sechs Proteine untersucht, die dasselbe Translokationsignal wie PfCDPK1 besitzen. Es konnte gezeigt werden, dass fünf der untersuchten Proteine mit der PfCDPK1 im Bereich der parasitophoren Vakuole sowie des tubovesikulären Systems co-lokalisiert sind. Deletionsmutanten, denen das Translokationssignal fehlte, sowie ein Peptid, das lediglich aus diesem bestand, bestätigten, dass die Translokation in die extrazellulären Kompartimente von keinen weiteren Faktoren, außer dem Signalmotiv abhängt. Mit PfCAP und PfRKIP konnten zwei Regulatoren der PfCDPK1 identifiziert werden. PfARM, Pfrab_5b sowie PfGAP45 sind Substrate der PfCDPK1. Mit Hilfe von massenspektrometrischen Messungen wurde der Phosphorylierungsstatus der untersuchten Proteine durch die PfCDPK1 sowie der Autophosphorylierungsstatus der Kinase bestimmt, um Rückschlüsse auf regulatorische Prozesse ziehen zu können.rnDie Phosphorylierung von PfGAP45 durch die PfCDPK1 steht vermutlich mit dem Invasionsprozess des Parasiten in direktem Zusammenhang, da gezeigt wurde, dass eine Hemmung der Kinase mit PP1 einen 90%igen Rückgang an neu infizierten Erythrozyten zur Folge hatte.rnrnThe biological functions of Plasmodium falciparum calcium dependent protein kinase 1 (PfCDPK1) from the pathogen causing malaria tropica were examined in parasite blood stages. To investigate the function of PfCDPK1 in the extracellular compartments of the parasite, six proteins that have the same signalling motif as PfCDPK1 were analyzed. Five of these proteins co-localized with PfCDPK1 in the parasitophorous vacuole and the tubovesicular system. Mutational analyses showed that the signalling motif itself is sufficient to target proteins to the extracellular compartments and that no further factors are required.rnWith PfCAP and PfRKIP, two regulatory systems of PfCDPK1 could be identified in addition to calcium. PfARM, Pfrab_5b and PfGAP45 are substrates of PfCDPK1. In order to obtain insight into possible regulatory mechanism, the PfCDPK1 phosphorylation sites of the individual substrates as well as the autophosphorylation sites of the kinase itself were determined by mass spectrometry. PfGAP45 phosphorylation seems to be involved in parasite invasion as the inhibition of PfCDPK1 by PP1 reduce the invasion of new erythrocytes by 90%. rnr