Technische Universität Dresden: Qucosa
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Assessing the physicochemical parameters of leachate from biowaste fractions in a laboratory setting, using the elusion method
No full textLeachate emissions, which are regarded as one of the primary polluters of groundwater and the environment, are unavoidable side effect of landfill operation. The leachate includes hazardous chemicals, heavy metals, suspended particles, and soluble organic molecules. The objective of this study was to simulate the leachate quality from the biowaste and assess its impact on groundwater pollution in a laboratory setting. For laboratory analysis, a variety of waste fractions that make up the waste composition of household bins in Windhoek were collected and mimicked in the laboratory for analysis. The aim of modeling these scenarios in the laboratory was to examine the quality of the leachate in the eluate when substantial volumes of biowaste were added to the residual samples. The analysis was carried out in accordance with the German Institute for Standardization's (DIN 12457) with respect to the process for sampling strategy and sample preparation. From the laboratory analyses, the values of pH decreased from 6.9 to 4.4 as the biowaste was increasing from 0 to 100 %, while EC was increasing with the increase in biowaste input from 0.6 to 4.99 mS/cm; equally, the concentrations of COD were increasing with the increase of biowaste input from 643 to 24,616 mg/l. These parameters had the strongest influence on the properties of leachate, as the high level of COD indicates the presence of high level of organic strength and a sign of organic pollution. The low or acidic pH values were also as a result of the production of volatile organic acids, which can cause the landfill leachate of such a nature to enhance pH of drinking water and contribute in trihalomethane formation which is a toxic substance for human health. High values of EC on the other hand indicate the discharge or other sources of pollution that has lowered the water body’s relative quality. From the findings, it can be concluded that leachate in this study is biodegradable and un-stabilized, as shown by the low pH levels and high COD concentrations. It also alluded that a change in physicochemical parameters, regardless of how little the concentration is, has the ability to change the quality of groundwater. According to this study, leachate was highly contaminated with organic matters. This has proven that the more biowaste inputs, the higher the concentrations of the physicochemical metrics, which can then alter the quality of groundwater. Hence, a recommendation for organic waste to be diverted from landfill sites or treated before landfilled. The findings from the leachate and groundwater samples of the Kupferberg showed that the landfill is mature methanogenic and stabilized stage, when compared to the pH of the laboratory results. COD values in the leachate samples are way higher than the permissible limit of the Namibian standard guidelines for drinking water, as well as the WHO guidelines. As alluded to by many researchers, high COD concentrations indicate high organic strength and pollution. Just as observed in the laboratory, conductivity is equally high in the leachate samples of the Kupferberg landfill, indicating high salts or dissolved inorganic components. This study can conclusively say that there is a relationship between the observed laboratory results and the actual field results, because of the similar trends they portray, noting that the filed values are always higher than the laboratory values. Hence, a proper correlation method is recommended
Die Vorhersage von Fahrkompetenz im höheren Lebensalter durch die Validität der Selbsteinschätzung
No full textDie Pflicht zur Vorsorge, andere Verkehrsteilnehmer im Straßenverkehr nicht zu gefährden, ist zentraler Bestandteil der Fahrerlaubnisverordnung. Allerdings setzt diese Vorsorgepflicht in vielen Fällen eine valide Selbsteinschätzung voraus, welche bei älteren Kraftfahrer*innen häufig beeinträchtigt ist. So weisen ältere Kraftfahrer*innen, die sich selbst überschätzen, eine Vielzahl fahrrelevanter Risikofaktoren auf. Unklar ist, wie die Validität der Selbsteinschätzung (VSA) und insbesondere das Ausmaß an Über- oder Unterschätzung mit der praktischen Fahrkompetenz im höheren Lebensalter zusammenhängt und deren Vorhersage erlaubt
Designing Vehicles and Roads for Accurate and Confident Assessments of (Automated) Vehicle Intent
No full textReducing uncertainty about vehicle intent is vital to facilitate safe and efficient interactions between (automated) vehicles and other road users. While numerous studies have examined how movement behavior and external human-machine interfaces (eHMIs) help convey intent, recent advances highlight the role of the traffic environment. Systems theory suggests that a vehicle, its observer, and the surrounding environment form a complex system, where interaction outcomes can only be optimized when one understands the interaction of all components. This suggests the need for more holistic approaches than have been pursued so far
Virtuelle Schritte für reale Sicherheit – Der Fußgängersimulator der BASt
No full textZufußgehen ist eine nachhaltige und gesundheitsfördernde Mobilitätsform, und ermöglicht eine aktive Teilhabe am öffentlichen Leben. Gleichzeitig gehören Fußgänger*innen auch zu den verletzlichsten Verkehrsteilnehmenden. Die Unfallstatistiken aus dem Jahr 2023 zeigten zuletzt wieder einen Anstieg verunglückter Fußgänger*innen. Um die Sicherheit und Attraktivität des Fußverkehrs zu erhöhen, sind kontrollierte Erhebungen sicherheitskritischer Situationen erforderlich. Ein experimenteller Ansatz kann dabei helfen, Maßnahmen kosteneffizient und wissenschaftlich zu untersuchen. Zu diesem Zweck entwickelte die BASt einen VR-basierten Fußgänger-Simulator, in dem man sich halbsitzend-halbstehend unendlich im virtuellen Raum bewegen kann
Investigating safety-related behavior of e-scooter riders using computer vision algorithms
No full textLangzeitergebnisse von Femurschaftfrakturen nach der Behandlung mittels elastisch-stabiler intramedullärer Nagelung (ESIN) im Kleinkindalter
No full textDie Wahl des richtigen Therapieverfahrens bei Femurschaftfrakturen im Kleinkindalter sorgt in Fachkreisen immer wieder für Diskussionen. Entsprechend der deutschen Leitlinie von 2023 werden operative Therapien, wie die elastisch-stabile Intramedullärnagelung erst ab einem Alter von drei Jahren oder einem Mindestgewicht von 10-15 kg empfohlen. Darunter sind konservative Therapien zu bevorzugen. (Dietzel, 2023) Dennoch hat die Zahl der operativ versorgten Femurschaftfrakturen in den vergangenen Jahren stetig zugenommen und wird auch bei den Kindern unter drei Jahren mit bis zu 50 % angegeben. (Strohm & Schmittenbecher, 2014)
Ziel dieser Studie war es, die funktionellen und klinischen Langzeitergebnisse von Femurschaftfrakturen im Kleinkindalter, nach der Therapie mit ESIN, darzustellen. Die Ergebnisse sollten anschließend mit den Daten konservativer und operativer Therapien aus der Literatur verglichen und in Kontext gesetzt werden. Damit sollten künftige Therapieentscheidungen vereinfacht werden.
Die Studie bestand aus einem retrospektiven Abschnitt, der die Daten von sechzig Kindern zwischen null und fünf Jahren erfasste. Alle Kinder erhielten aufgrund einer Femurschaftfraktur eine operative Therapie mit der ESIN. Retrospektiv wurden allgemeine demografische Daten und operationsbezogene Daten erfasst und ausgewertet. Im prospektiven Studienteil wurden diese Kinder zu einer weiteren klinischen Nachuntersuchung eingeladen. Vierundvierzig Kinder konnten so durchschnittlich 5,1 Jahre nach der Operation erneut untersucht werden. Dabei wurden die funktionellen Ergebnisse erfasst und Bewegungseinschränkungen im Alltag eruiert.
Die retrospektive Datenauswertung ergab in 10,0 % (n = 6) der Fälle Minor-Komplikationen und in 3,3 % der Fälle (n = 2) Major-Komplikationen. Verglichen mit der Literatur sind die Gesamtkomplikationsraten von ESIN und einer Gips-Therapie annähernd gleich und deutlich geringer als bei einer Pflasterextension. Bei den Major-Komplikationen scheint die ESIN- Therapie einer Gips-Behandlung leicht überlegen zu sein. (siehe Tabelle 7) Der durchschnittliche stationäre Aufenthalt unserer Patienten lag bei 7,4 ± 1,4 Tagen. Eine schmerzadaptierte Gewichtsbelastung war ab dem ersten postoperativen Tag erlaubt. Im Vergleich mit der Literatur zeigten sich für die ESIN deutlich kürzere Zeiten bis zur vollen Gewichtsbelastung gegenüber den konservativen Therapien. (siehe Tabelle 9) Eine interessante Nebenentdeckung war die hohe Frühgeburtenrate unserer Studie mit 14,3 % (n= 8). Diese ist verglichen mit der allgemeinen Frühgeburtenrate in Deutschland mehr als doppelt so hoch.
Die prospektive Datenauswertung ergab eine durchschnittliche Beinlängendifferenz unserer Patienten von 2,8 ± 5,1 mm. Nur ein Kind zeigte eine Beinlängendifferenz von mehr als 2 cm. Auch hierbei erzielte die ESIN verglichen mit einer Gips- und Pflasterextensionsbehandlung die besten Ergebnisse. (siehe Tabelle 10) Bei der Nachuntersuchung zeigte sich eine Differenz von 2,1° im durchschnittlichen Gesamtbewegungsumfang beider Hüftgelenke zugunsten der gesunden Seite. Es konnte eine signifikante positive Korrelation (r = 0,348) zwischen der Länge des stationären Aufenthaltes und dem Flynn Outcome Score nachgewiesen werden. Nicht signifikante, positive Korrelationen bestanden zwischen der Gewichtsperzentile zum Zeitpunkt der ESIN-Implantation und dem Flynn Outcome Score (r = 0,268), sowie zwischen der Schnitt-Naht-Zeit und der Länge des stationären Aufenthaltes.
Die elastisch-stabile intramedulläre Nagelung zeigte sich im Rahmen unserer Studie als sichere und komplikationsarme Therapiemöglichkeit im Kleinkindalter. Hinsichtlich des Auftretens von Major-Komplikationen, Beinlängendifferenzen und der Zeit bis zur Mobilisierung war sie konservativen Therapiemethoden überlegen.:1 Einleitung
1.1 Inzidenz und Ätiologie
1.2 Knochenaufbau
1.3 Knochenentwicklung
1.4 Frakturheilung im Wachstumsalter
1.5 Spontankorrekturen und Wachstumsstörungen am Femur
1.6 Therapiemöglichkeiten
1.7 Elastisch stabile intramedulläre Nagelung (ESIN)
2 Zielsetzung
3 Material und Methoden
3.1 Patientenkollektiv
3.2 Datenerhebung und klinische Untersuchung
3.3 Statistische Auswertung
4 Ergebnisse
4.1 Retrospektive Datenauswertung
4.2 Prospektive Datenauswertung
5 Diskussion
5.1 Diskussion der Methoden
5.2 Diskussion der Ergebnisse
5.2.1 Retrospektiv
5.2.2 Prospektiv
6 Zusammenfassungen (deutsch / englisch)
6.1 Zusammenfassung
6.2 Summary
7 Literaturverzeichnis
8 Anhang
8.1 Anschreiben
8.2 Untersuchungsbogen
8.3 Einverständniserklärung zur Fotodokumentation
9 Danksagung
10 AnlagenThe choice of the right treatment procedure for femoral shaft fractures in young children is a constant source of debate among experts. According to the German guideline of 2023, surgical therapies such as elastic stable intramedullary nailing are only recommended from the age of three years or a minimum weight of 10-15 kg. Below this age, conservative therapies are preferable. (Dietzel, 2023) Nevertheless, the number of surgically treated femoral shaft fractures has increased steadily in recent years and is also reported to be up to 50 % in children under the age of three. (Strohm & Schmittenbecher, 2014)
The aim of this study was to present the functional and clinical long-term results of femoral shaft fractures in infants after treatment with ESIN. The results were then to be compared with the data of conservative and surgical therapies from the literature and placed in context. This should simplify future treatment decisions.
The study consisted of a retrospective section that collected data from sixty children between the ages of zero and five. All children underwent surgical treatment with ESIN for a femoral shaft fracture. General demographic data and operation-related data were collected and analyzed retrospectively. In the prospective part of the study, these children were invited to a further clinical follow-up examination. Forty-four children were re-examined on average 5.1 years after the operation. The functional results were recorded and movement restrictions in everyday life were determined.
The retrospective data analysis revealed minor complications in 10.0 % (n = 6) of cases and major complications in 3.3 % of cases (n = 2). Compared to the literature, the overall complication rates of ESIN and cast therapy are almost the same and significantly lower than with plaster extension. For major complications, ESIN therapy appears to be slightly superior to cast treatment. (see Table 7) The average inpatient stay of our patients was 7.4 ± 1.4 days. Pain-adapted weight bearing was permitted from the first postoperative day. In comparison with the literature, ESIN showed significantly shorter times to full weight bearing compared to conservative therapies. (see Table 9) An interesting side discovery was the high preterm birth rate of 14.3% (n = 8) in our study. This is more than twice as high as the general preterm birth rate in Germany.
The prospective data analysis revealed an average leg length difference in our patients of 2.8 ± 5.1 mm. Only one child showed a leg length difference of more than 2 cm. Here too, ESIN achieved the best results compared to cast and plaster extension treatment. (see Table 10) The follow-up examination showed a difference of 2.1° in the average total range of motion of both hip joints in favor of the healthy side. A significant positive correlation (r = 0.348) was found between the length of hospitalization and the Flynn Outcome Score. There were non- significant, positive correlations between the weight percentile at the time of ESIN implantation and the Flynn Outcome Score (r = 0.268), as well as between the incision-suture time and the length of the inpatient stay.
Elastic stable intramedullary nailing was shown in our study to be a safe and low-complication treatment option in infants. With regard to the occurrence of major complications, leg length discrepancies and time to mobilization, it was superior to conservative treatment methods.:1 Einleitung
1.1 Inzidenz und Ätiologie
1.2 Knochenaufbau
1.3 Knochenentwicklung
1.4 Frakturheilung im Wachstumsalter
1.5 Spontankorrekturen und Wachstumsstörungen am Femur
1.6 Therapiemöglichkeiten
1.7 Elastisch stabile intramedulläre Nagelung (ESIN)
2 Zielsetzung
3 Material und Methoden
3.1 Patientenkollektiv
3.2 Datenerhebung und klinische Untersuchung
3.3 Statistische Auswertung
4 Ergebnisse
4.1 Retrospektive Datenauswertung
4.2 Prospektive Datenauswertung
5 Diskussion
5.1 Diskussion der Methoden
5.2 Diskussion der Ergebnisse
5.2.1 Retrospektiv
5.2.2 Prospektiv
6 Zusammenfassungen (deutsch / englisch)
6.1 Zusammenfassung
6.2 Summary
7 Literaturverzeichnis
8 Anhang
8.1 Anschreiben
8.2 Untersuchungsbogen
8.3 Einverständniserklärung zur Fotodokumentation
9 Danksagung
10 Anlage
Truncated nonsmooth Newton multigrid for phase-field brittle-fracture problems, with analysis
No full textWe propose the truncated nonsmooth Newton multigrid method (TNNMG) as a solver for the spatial problems of the small-strain brittle-fracture phase-field equations. TNNMG is a nonsmooth multigrid method that can solve biconvex, block-separably nonsmooth minimization problems with linear time complexity. It exploits the variational structure inherent in the problem, and handles the pointwise irreversibility constraint on the damage variable directly, without regularization or the introduction of a local history field. In the paper we introduce the method and show how it can be applied to several established models of phase-field brittle fracture. We then prove convergence of the solver to a solution of the nonsmooth Euler–Lagrange equations of the spatial problem for any load and initial iterate. On the way, we show several crucial convexity and regularity properties of the models considered here. Numerical comparisons to an operator-splitting algorithm show a considerable speed increase, without loss of robustness
Anatomical and biomechanical properties of strengthening structures in adventitious root-shoot junctions
No full textAdventitious roots fulfill a variety of roles for the plants that develop them, be that for nutrition, anchorage, propagation or a combination of those. While they have been the subject of ongoing research for decades, the anatomy and properties of how they join to the plant shoot have not received much attention. This thesis investigates the aspect of the root-shoot junction in detail, both from an anatomical and biomechanical point of view and for their biomimetic potential as inspiration for carbon reinforced concrete structures. The research has been conducted on exemplary plants from the Cactaceae, Araceae, Caricaceae and Poaceae. A combination of microscopical, tomographical and biomechanical methods was used to characterize the connection between root and shoot. In each case, an unique junction anatomy was found, that was adapted to the respective overarching plant anatomy and the specific role of the root for each species. In Cactaceae, the root is joined with a preferential direction to the cacti-specific wooden central cylinder. In the studied Araceae, to root is joined directly to the central vascular system and has to pass through a partial endodermis. In the Poaceae, the circularily arranged vascular bundles of the root join on all sides to the longitudinal vascular bundles of the shoot. In the Caricaceae, the net-like fibre structure of the shoot is found also in the root with again, a directional junction. In most cases, these junction details have not been reported before. The inspirational potential of the findings will have to be
studied further for suitable applications
An interaction-based drug discovery screen explains known SARS-CoV-2 inhibitors and predicts new compound scaffolds
No full textThe recent outbreak of the COVID-19 pandemic caused by severe acute respiratory syndrome-Coronavirus-2 (SARS-CoV-2) has shown the necessity for fast and broad drug discovery methods to enable us to react quickly to novel and highly infectious diseases. A well-known SARS-CoV-2 target is the viral main 3-chymotrypsin-like cysteine protease (Mpro), known to control coronavirus replication, which is essential for the viral life cycle. Here, we applied an interaction-based drug repositioning algorithm on all protein-compound complexes available in the protein database (PDB) to identify Mpro inhibitors and potential novel compound scaffolds against SARS-CoV-2. The screen revealed a heterogeneous set of 692 potential Mpro inhibitors containing known ones such as Dasatinib, Amodiaquine, and Flavin mononucleotide, as well as so far untested chemical scaffolds. In a follow-up evaluation, we used publicly available data published almost two years after the screen to validate our results. In total, we are able to validate 17% of the top 100 predictions with publicly available data and can furthermore show that predicted compounds do cover scaffolds that are yet not associated with Mpro. Finally, we detected a potentially important binding pattern consisting of 3 hydrogen bonds with hydrogen donors of an oxyanion hole within the active side of Mpro. Overall, these results give hope that we will be better prepared for future pandemics and that drug development will become more efficient in the upcoming years
Thermomechanical Modeling of the Stabilization Process for Carbon Fiber Production
No full textWithin carbon fiber manufacturing, the stabilization process is the most time- and energy-intensive process due to the complexity of chemical structure transformation. Therefore, optimization is strictly required to enable cost-efficient stabilization processes. For the first time, a hybrid semi-parametric model for continuous stabilization is developed to prognose stabilization progress and density of the stabilized fiber. The proposed model takes the process parameters like dwell time, stabilization temperature, and fiber stretching as well as precursor properties, such as fiber density, into account. Finally, the proposed hybrid semi-parametric model offers a novel plant-transferable optimization solution for model-based energy optimization in the stabilization process