A study on the effects of hidden safety when assessing existing structures

In many instances, the safety of existing structures can no longer be demonstrated by standard code-based assessments. Reasons for this include changes in the code, changes in the demands on the structures and deterioration. To address this problem, it is common practice to perform a more detailed assessment utilizing advanced models. In this way, many structures can be shown to comply with safety requirements, even if they cannot be verified by standard assessments. The standard code models are often conservatively biased. This leads to designs which include hidden safety. If the reassessment is performed with more advanced models in lieu of standard models, the hidden safety can vanish. Concurrently, the reduced uncertainty of advanced models may compensate this safety reduction. In this paper we investigate this issue on a hypothetical population of existing bridge structures under traffic. We consider that the standard code model is exchanged by an advanced traffic load simulation

Have productivity and pay decoupled in the UK?

In the long-run at the macro level, the real pay of workers tends to follow labour productivity. In recent years, however, there have been concerns that this relationship has broken down and that pay has become "decoupled" from productivity, growing much more slowly. If the mean hourly compensation of workers grows more slowly than GDP per hour, this means the labour share will fall and this has been a well-documented phenomenon in the US since the early 1980s. By contrast, we show that in the UK, employee mean hourly compensation has grown at the same rate as labour productivity between 1981 and 2019. Although there has been no "net decoupling" in this sense, there has been a large divergence between median employee hourly wage growth and productivity growth of about 25 percentage points. About three-fifths of this "total decoupling" is due to increasing inequality (mean wages growing faster than median wages) and one-third is due to the increased non-wage compensation costs, in particular employer pension contributions. However, this analysis relates to employee compensation. The average self-employed worker has seen their income grow by only 50%, compared to 80% for the average employee. Using micro-data, we show that this gap can essentially be all explained by (i) the growth in the numbers of "solo self-employed" (who have relatively low incomes), and (ii) a much greater fall in hours worked by the self-employed than for the employed. Finally, if we "correct" the labour share for self-employment and non-wage labour costs, the UK labour share has fallen by about 3.5 percentage points over the last four decades

Design and operations optimization of membrane separation for flexible carbon capture from natural gas combined cycle systems

We explore the concept of flexible carbon capture using membrane separation. Flexible carbon capture has been studied in recent years as a measure to decarbonize fossil-fired power generation in response to electricity market conditions, including varying electricity prices and/or fluctuating electricity supply requirements. The importance of flexible operation of carbon capture systems is highlighted by the increasing penetration of intermittent energy generation from renewable sources such as wind and solar PV. To accommodate the integration of renewable energy into the grid, fossil-fired power plants would need to generate varying electricity load, producing flue gas with varying characteristics and at varying volumes. Carbon capture systems in a high-renewables grid will be required to operate flexibly to respond to these changes. Flexible carbon capture has been studied for amine absorption,1-2 a leading CCS technology. This work explores the possibility of flexible carbon capture using membrane separation, a promising alternative to amine absorption. In particular, membranes are considered to be very responsive to system changes and require very short start-up times.3 In addition, membrane separation has advantages such as having a smaller footprint, being more environmentally benign (no corrosive chemicals involved in the separation process), and potentially incurring lower separation energy. In this work, we perform optimization to determine the optimal process design and time-varying operations of a polymeric membrane system separating CO2 from a natural gas combined cycle (NGCC) with wind energy integration. The total net present value (NPV) of the gas turbines and membrane system is maximized. Both design and operations of the capture plant are optimized. Design decision variables include membrane process configuration, membrane size, CO2/N2 selectivity and CO2 permeance (two key membrane properties relevant to separation performance), and compressor and vacuum pump sizes. These parameters are determined before a capture unit is built. After the plant is built, operational decision variables include gas flowrates, the pressure ratio across the membrane and permeate-side (low-pressure side) pressure. These are parameters that can be adjusted, within limits, given electricity market conditions for a given time period. Time-varying electricity output from gas turbines as well as the associated flue gas flowrate and composition will be determined by HyPPO, an in-house software developed at Stanford University for modeling and optimization of flexible and renewable-integrated power systems. HyPPO models beneficial operating strategies for a set of statistically representative days. HyPPO results will be used with membrane separation models for various process configurations as modeled in MATLAB. 1. Cohen, S. M.; Rochelle, G. T.; Webber, M. E., Optimizing post-combustion CO2 capture in response to volatile electricity prices. International Journal of Greenhouse Gas Control 2012, 8, 180–195. 2. Mac Dowell, N.; Shah, N., The multi-period optimisation of an amine-based CO2 capture process integrated with a super-critical coal-fired power station for flexible operation. Computers & Chemical Engineering 2015, 74, 169–183. 3. Brunetti, A.; Scura, F.; Barbieri, G.; Drioli, E., Membrane technologies for CO2 separation. Journal of Membrane Science 2010, 359 (1), 115–125

Ceramide-enriched membrane domains

AbstractCellular activation involves the re-organization of receptor molecules and the intracellular signalosom in the cell membrane. Recent studies indicate that specialized domains of the cell membrane, termed rafts, are central for the spatial organization of receptors and signaling molecules. Rafts are converted into larger membrane platforms by activity of the acid sphingomyelinase, which hydrolyses raft-sphingomyelin to ceramide. Ceramide molecules spontaneously associate to form ceramide-enriched microdomains, which fuse to large ceramide-enriched membrane platforms. The acid sphingomyelinase is activated by multiple stimuli including CD95, CD40, DR5/TRAIL, CD20, FcγRII, CD5, LFA-1, CD28, TNF, the Interleukin-1 receptor, the PAF-receptor, CD14, infection with P. aeruginosa, S. aureus, N. gonorrhoeae, Sindbis-Virus, Rhinovirus, treatment with γ-irradiation, UV-light, doxorubicin, cisplatin, disruption of integrin-signaling and under some conditions of developmental death. Ceramide-enriched membrane platforms serve the clustering of receptors, the recruitment of intracellular signaling molecules and the exclusion of inhibitory signaling factors and, thus, facilitate signal transduction initiated by the specific stimulus

Berechnung kinematischer Getriebeabmessungen zur Kalibrierung von Führungsgetrieben durch Messung

Führungsgetriebe die durch Servomotoren angetrieben werden, benötigen für definierte Stellungen des Abtriebsglieds eine programmierte Funktion (elektronische Kurvenscheibe). Diese leitet sich aus dem möglicherweise fehlerbehafteten kinematischen Modell des Getriebes ab (inverse Kinematik). Zur Verbesserung der Genauigkeit der Führungsbewegung wird ein Verfahren zur Justierung der Übertragungsfunktion auf Basis des Newton-Verfahrens unter Nutzung der Singulärwertzerlegung vorgestellt. Dabei werden die realen Getriebeabmessungen anhand einer Messung berechnet und werden anschließend korrigiert zur Anpassung der Übertragungsfunktion verwendet

Zhanzhuang gong

In dieser Arbeit liegt der Fokus auf der Beschreibung der inneren Bewegung in der von außen unverändert erscheinenden Übungsposition zhanzhuang gong, welche auch als Übung der Himmel-Erd-Säule bezeichnet wird. Zhanzhuang gong wird als zentrale Übungspraxis der inneren Kampfkunst Yiquan vorgestellt. In narrativen autobiographischen Texten wird die Phänomenologie meiner Wahrnehmung des Trainings beschrieben, welche sich im Text in bildhafter Sprache wie eine innere Landschaft der kinetischen Erfahrung entfaltet. Neben dem evozierenden autoethnographischen Forschungsansatz bietet die theoretische Auseinandersetzung mit den Bereichen Autoethnographie und Kampfkunst, sowie eine Präsentation weiterer empirischer Daten der Feldforschung, eine umfassende Sicht auf das Forschungsfeld an.This thesis focuses on zhanzhuang, a central position of Yiquan practice, which is an internal martial art, originated in China. The zhanzhuang position, externally viewed as unchanged, is characterized by an inner movement and is known in English as heaven-earth-pile-standing. In autoethnographical narratives based on empirical data from field research, the phenomenology of my own experience and perception of Yiquan training is unfolded. By employing a figurative language it illustrates the inner landscape in a kinetic experience. This thesis also includes a theoretical analysis of the fields of autoethno-graphy and martial arts, offering a pioneering and comprehensive review on these subjects

Untersuchungen zur Durchführung einer metaphylaktischen Behandlung bei Kühen mit erhöhtem Risiko für puerperale Gebärmutterentzündungen

Ziel der vorliegenden Studie war es, eine Verminderung der Krankheitsinzidenz und eine positive Beeinflussung verschiedener Stoffwechsel- und Reproduktionsparameter bei Kühen, bei denen ein erhöhtes Risiko für puerperale Gebärmutterentzündungen angenommen wurde, mit einer metaphylaktischen Behandlung mit Gonadotropin Releasing Hormon und Prostaglandin F2α zu untersuchen. Die vorliegende Untersuchung basiert auf den Studien von SCHMAUßER (2006), EULER (2009) und STOCK (2009). In diesen Arbeiten wurde aufgezeigt, dass es mittels Bestimmung der Bilirubinkonzentration im Serum in der ersten Woche post partum (p.p.) möglich ist, Tiere zu ermitteln, die ein erhöhtes Risiko aufweisen, eine Gebärmutterentzündung zu entwickeln. Als geeigneter Grenzwert zeigte sich dabei eine Bilirubinkonzentration ≥ 8,2 μmol/l. In insgesamt 18 Milcherzeugerbetrieben wurden 276 Kühe und Kalbinnen von der Kalbung an bis vier Wochen p.p. untersucht. Einmal pro Woche wurde allen Tieren aus der Vena jugularis Blut entnommen und im Serum Bilirubin, β-Hydroxybuttersäure (BHBA), Freie Fettsäuren (FFS), Glutamat-Dehydrogenase (GLDH) und Aspartat-Aminotransferase (AST) bestimmt sowie der Body Condition Score (BCS) ermittelt. In der ersten Woche p.p. wurden die Tiere mit Hilfe des Bilirubinwertes in Risikotiere und Tiere, die kein erhöhtes Risiko aufwiesen, eine Gebärmutterentzündung zu entwickeln, eingeteilt. Jeweils die Hälfte jeder Gruppe wurde mit einer Kombinationsbehandlung aus Gonadotropin Releasing Hormon (GnRH) in der zweiten Woche p.p. und Prostaglandin F2α (PGF2α) in der dritten Woche p.p. behandelt, die andere Hälfte blieb als Kontrollgruppe unbehandelt. In der vierten Woche p.p. wurden alle Tiere transrektal und vaginoskopisch auf das Vorliegen einer Gebärmutterentzündung untersucht. Weiterhin wurden Geburtsdatum, Laktationsnummer, Kalbeverlauf, Rast- und Güstzeiten, der Erstbesamungserfolg (EBE), Erstbesamungsindex (EBI) und der Trächtigkeitsindex (TI) dokumentiert. Außerdem wurde die betriebsspezifische Gabe von glukoplastischen Substanzen wie Propylenglykol in den Auswertungen berücksichtigt. 11,6 % der Tiere wurden als „Risikotiere“ eingestuft. Eine signifikant höhere Krankheitsinzidenz der Risikotiere wurde nicht festgestellt. Die Risikotiere wiesen signifikant höhere Bilirubin- und FFS-Werte zu allen Untersuchungszeitpunkten, erhöhte BHBA-Werte in der ersten Woche p.p. und erhöhte GLDH- und AST-Werte in der ersten bis dritten Woche p.p. auf. Signifikante Unterschiede zwischen den behandelten und den Kontrolltieren der Risikogruppe waren nicht zu erkennen. Es wurde jedoch beobachtet, dass die erhöhten Bilirubin-, Freie Fettsäure- und ASTKonzentrationen der behandelten Risikotiere tendenziell sanken, während die Werte der Kontrollrisikotiere erhöht blieben oder sogar weiter anstiegen. Die Streuung der Werte der behandelten Risikotiere verringerte sich im Verlauf der Untersuchung, bei den Kontrolltieren vergrößerte sie sich. Unbehandelte Risikotiere hatten signifikant längere Rastzeiten als Kontrolltiere ohne erhöhtes Erkrankungsrisiko. Die Güstzeiten unterschieden sich nicht signifikant zwischen den Gruppen. Die unbehandelten Risikotiere zeigten jedoch die längsten Güstzeiten. Der Erstbesamungserfolg der Risikotiere war signifikant geringer als bei den Kontrolltieren, die kein erhöhtes Risiko aufwiesen. Bei den Tieren, denen kein Propylenglykol gefüttert wurde, erkrankten signifikant mehr Kontrolltiere in der Risikogruppe als Tiere ohne ein erhöhtes Risiko für die Entwicklung einer Gebärmutterentzündung. Die prozentuale Erkrankungshäufigkeit der behandelten Risikotiere war so groß wie bei den Tieren, die kein erhöhtes Risiko aufwiesen. Bei den Tieren, die Propylenglykol erhalten hatten, konnten keine signifikanten Unterschiede der Erkrankungshäufigkeiten zwischen den Gruppen festgestellt werden.The aim of the present study was to analyze if a metaphylactic treatment with gonadotropin releasing hormone (GnRH) and prostaglandin F2α (PGF2α) on cows with an increased risk of puerperal infections of the uterus can reduce the incidence of uterine infections, several metabolic and reproductive parameters. The present research is based upon the studies of SCHMAUßER (2006), EULER (2009) and STOCK (2009). These papers show that it is possible to identify the animals with an increased risk of puerperal infection of the uterus by means of the concentration of total bilirubin in the bloodserum in the first week post partum (p.p.). The proper threshold is a bilirubin-concentration of 8.2 μmol/l. In 18 dairy-farms 276 cows and heifers were examined in the period from calving until four weeks post partum. Once a week blood samples were taken from all animals from the jugular vein and analysed for total bilirubin, β-hydroxybutyrate (BHBA), non-esterified fatty acids (NEFA), glutamate dehydrogenase (GLDH) and aspartate aminotransferase (AST). The body condition score was evaluated. In the first week p.p. the animals were divided into animals with an increased risk of puerperal uterine infections and animals without an increased risk by means of the concentration of bilirubin. Half of each group was treated with a combination of a GnRH in the second week p.p. and PGF2α in the third week p.p.. The rest of the animals was left untreated as a control group. In the fourth week p.p. all animals were examined by means of rectal palpation and vaginal examination to see whether an infection of the uterus could be diagnosed. Furthermore, the date of birth, lactation number, problems at parturition, time from calving to first insemination, days open, first service conception success, first service index and pregnancy index were documented. Also the use of glucogenic substances on each farm was included in interpretation. 11.6 % of the animals were classified to have an increased risk. A significantly higher incidence of infections in animals with an increased risk was not noticed. The animals with an increased risk had significantly higher levels of total bilirubin and NEFA during the whole time. Elevated concentrations of BHBA were detectable in the first week p.p. and elevated concentrations of GLDH and AST from the first until the third week p.p.. Significant differences between treated and untreated riskanimals were not apparent. But it was observable that the elevated concentrations in treated risk-animals had a tendency to decrease, while the concentrations in the control-animals stayed on the higher level or even increased. The statistical spread of concentrations decreased in treated risk-animals during the research and increased in untreated riskanimals. Untreated risk-animals had a significantly longer time from calving to first insemination than animals without an increased risk of puerperal infection of the uterus. Days open were not significantly different between the groups but untreated risk-animals had the most days open. First service success was significantly lower in risk-animals than in animals without an increased risk. Those untreated risk-animals who were not treated with propylene glycol developed uterine infections significantly more often than animals without an increased risk. The incidence of uterine infections in percent in treated risk-animals was as same as in animals without an increased risk. There were no differences in the frequency of disease in animals given propylene glycol

Structural properties of magnetic nanoparticles determine their heating behavior - an estimation of the in vivo heating potential

Magnetically induced heating of magnetic nanoparticles (MNP) in an alternating magnetic field (AMF) is a promising minimally invasive tool for localized tumor treatment by sensitizing or killing tumor cells with the help of thermal stress. Therefore, the selection of MNP exhibiting a sufficient heating capacity (specific absorption rate, SAR) to achieve satisfactory temperatures in vivo is necessary. Up to now, the SAR of MNP is mainly determined using ferrofluidic suspensions and may distinctly differ from the SAR in vivo due to immobilization of MNP in tissues and cells. The aim of our investigations was to study the correlation between the SAR and the degree of MNP immobilization in dependence of their physicochemical features. In this study, the included MNP exhibited varying physicochemical properties and were either made up of single cores or multicores. Whereas the single core MNP exhibited a core size of approximately 15 nm, the multicore MNP consisted of multiple smaller single cores (5 to 15 nm) with 65 to 175 nm diameter in total. Furthermore, different MNP coatings, including dimercaptosuccinic acid (DMSA), polyacrylic acid (PAA), polyethylenglycol (PEG), and starch, wereinvestigated. SAR values were determined after the suspension of MNP in water. MNP immobilization in tissues was simulated with 1% agarose gels and 10% polyvinyl alcohol (PVA) hydrogels. The highest SAR values were observed in ferrofluidic suspensions, whereas a strong reduction of the SAR after the immobilization of MNP with PVA was found. Generally, PVA embedment led to a higher immobilization of MNP compared to immobilization in agarose gels. The investigated single core MNP exhibited higher SAR values than the multicore MNP of the same core size within the used magnetic field parameters. Multicore MNP manufactured via different synthesis routes (fluidMAG-D, fluidMAG/12-D) showed different SAR although they exhibited comparable core and hydrodynamic sizes. Additionally, no correlation between ζ-potential and SAR values after immobilization was observed. Our data show that immobilization of MNP, independent of their physicochemical properties, can distinctly affect their SAR. Similar processes are supposed to take place in vivo, particularly when MNP are immobilized in cells and tissues. This aspect should be adequately considered when determining the SAR of MNP for magnetic hyperthermia