Foundry parameters for casting high-aluminum lightweight steel in complex shapes

This work investigated the liquid metal treatment and molding practices for Fe- 30wt.%Mn-9wt.%Al-1wt.%Si-0.9wt.%C-0.5wt.%Mo steel. The goal of this research was to determine the process conditions that would produce a tough Fe-Mn-Al-C alloy and the appropriate mold design to produce a defect-free P900 plate. Notch toughness of age-hardenable Fe-Mn-Al-C alloys decreases as phosphorus increases. Thermodynamic calculations and experimental work show that additions of Ca followed by Ce can be used to mitigate the deleterious effects of phosphorus, and the addition of Ar-stirring can be used to decrease the number of harmful aluminum nitride inclusions. In the solution-treated and aged condition (Brinell hardness 317-330), the room temperature Charpy Vnotch (CVN) impact energies increased from 33 J to 92 J as a result of ladle refinement using calcium wire, misch metal additions, and argon stirring with a lance. The addition of Ar-stirring decreased the number of inclusions by more than 90% when compared with the untreated heat. Liquid Fe-Mn-Al-C alloys have casting characteristics significantly different from regular carbon steel; specifically, the high aluminum content promotes a strong tendency to re-oxidize and form surface films during mold filling. These melt properties promote the formation of oxide film laps and cold shuts in thin-walled castings. This research used MagmaSoft modeling software in conjunction with experiments to study the castability of Fe-Mn-Al-C steel P900 armor plates. The effects of superheat and venting procedures were evaluated for different molding techniques including bonded olivine sand molds tilted at both 0⁰ and 15⁰ from horizontal and preheated investment shell molds vertically oriented with a bottom-filled gating system. The best castings were produced in vertically oriented, bottom-filled, ceramic investment shell molds with a superheat of 300C⁰ and poured directly from the furnace into a preheated investment shell at 800⁰C. Successful P900 castings were also obtained from the tilted bonded olivine sand molds when poured with a superheat above 300C⁰ --Abstract, page iv

MBOAT7 und weitere Risikofaktoren für die Progression der PNPLA3-assoziierten Steatohepatitis

Bisher konnte gezeigt werden, dass Träger des Adiponutrins (PNPLA3) Genotyps p.I148M ein erhöhtes Risiko für die Entwicklung einer hepatischen Steatose und Fibrose haben (Krawczyk et al. Journal of Lipid Research 2018). In der Hochrisikogruppe der Patienten mit homozygoter p.I148M PNPLA3-Mutation ist die Steatose der Leber für die Prognose der Lebererkrankung von entscheidender Bedeutung. Andererseits wurde festgestellt, dass Mutationen im MBOAT7-Gen die Leberschädigung und -fibrose verstärken. Ziel dieser Arbeit ist daher die Analyse der Wirkung des MBOAT7-Risikoallels rs641738 und metabolischer Risikofaktoren auf die Steatose und Fibrose der Leber bei homozygoten Trägern des mutierten PNPLA3-Allels. Insgesamt wurden 2.278 Patienten auf die PNPLA3-Variante getestet. Davon waren 152 Patienten (6,7%) homozygote Träger des PNPLA3-Risikoallels. Klinische, laborchemische und bildgebende Daten einschließlich der mittels transienter Elastographie bestimmten CAP (Contolled attenuation parameter zur Quantifizierung der Steatose) und LSM (Liver stiffness measurement zur Quantifizierung der Fibrose) wurden erhoben. Die Genotypisierung der MBOAT7-Variante rs641738 erfolgte durch Polymerase-Kettenreaktion-basierte allelische Diskriminierung. Die sich ergebenden Risikogruppen wurden bezüglich ihrer Phänotypen verglichen. Die Fibrosestadien bei p.I148M-homozygoten Patienten mit nicht-alkoholischer Fettlebererkrankung waren mit metabolischen Risikofaktoren, aber nicht den MBOAT7-Genotypen assoziiert. Die Prävalenz von Zirrhose und hepatozellulärem Karzinom wurde ebenfalls nicht von der MBOAT7-Allelausprägung beeinflusst, jedoch ließ sich ein Rückgang der anhand des CAP gemesssenen Steatose pro zusätzlich mutiertem MBOAT7-Allel nachweisen. Da eine Abnahme der Steatose bei schon fortgeschrittener Lebererkrankung als prognostisch ungünstiges Zeichen gilt, könnten Patienten mit PNPLA3- und MBOAT7-Homozygotie eine vulnerable Patientengruppe mit nicht-alkoholischer Fettlebererkrankung darstellen, bei denen sich exogene Risiken besonders nachteilig auswirken.MBOAT7 and exogeneous risk factors in the progression of PNPLA3-associated steatohepatitis: Carriers of the adiponutrin (PNPLA3) p.I148M genotype have an increased risk of hepatic steatosis and fibrosis (Krawczyk et al. Journal of Lipid Research 2018). Steatosis is a decisive marker for the prognosis of chronic liver diseases in the high-risk group of PNPLA3 mutation carriers. Furthermore it was found that mutations in the MBOAT7 gene worsen hepatic fibrosis and hepatocellular damage. Here we aim to investigate how the MBOAT7 rs641738 variant and metabolic risk factors affect liver steatosis and fibrosis in patients who are homozygous carriers of the PNPLA3 risk variant p.I148M. In total, 2.278 patients were screened for the PNPLA3 variant. Overall, 152 (6,7%) of these patients were homozygous carriers of the PNPLA3 p.I148M genotype. Clinical, laboratory and imaging data were collected, including non-invasive liver stiffness measurements (LSM, marker of hepatic fibrosis) and controlled attenuation parameter (CAP, marker of hepatic steatosis) by transient elastography in all patients. MBOAT7 rs641738 was genotyped using polymerase-chain-reaction-based allelic discrimination assays. The genotype to phenotype correlations of the resulting cohort were analysed. The fibrosis stages in p.I148M homozygous patients with non-alcoholic fatty liver disease were associated with metabolic risk factors, but not with MBOAT7 genotypes. The frequency of cirrhosis and hepatocellular carcinoma was not influenced by MBOAT7 alleles either. However, a decrease of hepatic steatosis, as measured by CAP, per additionally mutated MBOAT7 allele was found. Since a decrease of steatosis in patients with advanced liver disease is considered as an unfavorable prognostic marker, patients with both homozygous mutated PNPLA3 and MBOAT7 allele could represent a vulnerable group of patients with non-alcoholic fatty liver disease in whom exogenous factors confer significant risk

Coffeehouse Sociability: Samuel Pepys and the Creation of Networks in Late Seventeenth Century England

Title from PDF of title page viewed January 20, 2022Thesis advisor: David FreemanVitaIncludes bibliographical references (page 47-49)Thesis (M.A.)--Department of History. University of Missouri--Kansas City, 2021The aim of this work is to address how coffeehouse culture in seventeenth- and eighteenth-century England facilitated the creation of networks. The emergence of the coffeehouse in London created a new social atmosphere for men to interact with one another. Unlike the taverns Englishmen frequented, coffeehouses provided a new, sobering environment to discuss politics, science, news, and business. This new public sphere attracted men from different social standings in society to meet and discuss numerous topics over a dish of coffee. Men like Samuel Pepys saw the importance of these coffeehouses to propel his social standing. Pepys’s diary provides a rare account of one man’s visits to numerous coffeehouses around London. Between 1660-1665, Pepys experienced coffeehouses that dealt with politics, commercial interests, and news, which fostered different connections and networks to enhance his position. By first understanding the social aspects of the coffeehouses, I can examine three different areas of coffeehouse association – politics, news, and finance – and how their specific commercial agenda brought together like-minded men that facilitated the establishment of networks. By following Pepys’s diary through the high coffeehouse years of 1660-1665, and interspersed with literary, economic, and printed discursive texts, we can see how the coffeehouse created ways for Pepys to become politically, economically, and socially aware of a public sphere continuously expanding across London.Coffeehouse Sociability -- Seventeenth-Century Politics and Coffeehouse Culture -- Commercial Competition and the Coffeehouse -- Coffeehouses and the Origins of the Origins of the Popular Press -- Conclusio

4D Printing of a Light-Driven Soft Actuator with Programmed Printing Density

There is a growing interest in the concept of four-dimensional (4D) printing that combines a three-dimensional (3D) manufacturing process with dynamic modulation for bioinspired soft materials exhibiting more complex functionality. However, conventional approaches have drawbacks of low resolution, control of internal micro/nanostructure, and creation of fast, complex actuation due to a lack of high-resolution fabrication technology and suitable photoresist for soft materials. Here, we report an approach of 4D printing that develops a bioinspired soft actuator with a defined 3D geometry and programmed printing density. Multiphoton lithography (MPL) allows for controlling printing density in gels at pixel-by-pixel with a resolution of a few hundreds of nanometers, which tune swelling behaviors of gels in response to external stimuli. We printed a 3D soft actuator composed of thermoresponsive poly(N-isopropylacrylamide) (PNIPAm) and gold nanorods (AuNRs). To improve the resolution of printing, we synthesized a functional, thermoresponsive macrocrosslinker. Through plasmonic heating by AuNRs, nanocomposite-based soft actuators undergo nonequilibrium, programmed, and fast actuation. Light-mediated manufacture and manipulation (MPL and photothermal effect) offer the feasibility of 4D printing toward adaptive bioinspired soft materials. Copyright © 2020 American Chemical Society

High prevalence of ESBL-producing Klebsiella pneumoniae in clinical samples from central Côte d'Ivoire

Objectives: Infections caused by multidrug-resistant Enterobacterales pose a significant challenge to clinical patient care, particularly in resource-constrained settings where epidemiological data on antimicrobial resistance are scarce. The aim of this study was to determine the prevalence of extended spectrum beta-lactamase-(ESBL)-producing Klebsiella pneumoniae among clinical samples from a teaching hospital in Bouaké, central Côte d’Ivoire. Methods: Clinical specimens were collected from sterile and non-sterile body sites and were subjected to microbiological diagnostics (April 2016-June 2017). The antimicrobial susceptibility patterns of K. pneumoniae were analysed using automated resistance testing and double-disk diffusion to test for ESBL production. Multiplex PCR was carried out to determine the presence of the resistance-conferring genes blaCTX-M, blaSHV and blaTEM. Results: A total of 107 isolates were included, most of which were obtained from bloodstream (39%; n = 42) and urinary tract infections (39%; n = 42). Among all K. pneumoniae isolates, 84% (n = 90) were ESBL producers, many of which were also not susceptible to sulfonamides (99%), quinolones (81%) and aminoglycosides (79%). The majority of ESBL-producing strains harboured all three investigated bla genes. Conclusion: The high prevalence of ESBL-producing K. pneumoniae in clinical isolates from Côte d’Ivoire calls for revised empirical treatment regimens in critically ill patients with suspected Gram-negative infections, and the establishment of antimicrobial resistance surveillance systems

On‐site non‐destructive determination of the remanent magnetization of archaeological finds using field magnetometers

The determination of the natural remanent magnetization (NRM) of archaeological features can be used for magnetic modelling, joining of shards, archaeomagnetic dating or the investigation of the firing–cooling–collapsing order of ancient buildings. The measurement of NRM is normally conducted on cylindrical or cubic samples in the laboratory. Nevertheless, archaeological finds should preferably not be destroyed, and laboratory instruments are high in costs. Therefore, we propose a lightweight and portable measurement set-up including already available field magnetometers (preferably caesium magnetometers) in which the archaeological sample of arbitrary shape, in our case a piece of daub, is mounted inside a gimbal to be rotated in all directions. The magnetic field of the sample is measured at a large number of rotational positions with the magnetometer kept at fixed position. In these measurements, the unknown direction of the NRM vector of the sample is rotated, whereas the average magnetic susceptibility of the sample and the ambient magnetic field are constant and known. Hence, the vector of NRM can be determined through least-squares inversion. For the inversion computation, the sample volume is discretized either as voxel model or approximated as an equivalent sphere. Under certain conditions depending on sample–sensor distance, dipole moment and radius of the sample, the approximation by a sphere is valid without effect on the accuracy of results.This is accurate enough, for example, to determine from daub pieces of burnt house remains whether the building was burnt and cooled before or after it collapsed

Ammonia adsorption on iron phthalocyanine on Au(111): Influence on adsorbate-substrate coupling and molecular spin.

The adsorption of ammonia on Au(111)-supported monolayers of iron phthalocyanine has been investigated by x-ray photoelectron spectroscopy, x-ray absorption spectroscopy, and density functional theory calculations. The ammonia-induced changes of the x-ray photoemission lines show that a dative bond is formed between ammonia and the iron center of the phthalocyanine molecules, and that the local spin on the iron atom is quenched. This is confirmed by density functional theory, which also shows that the bond between the iron center of the metalorganic complex and the Au(111) substrate is weakened upon adsorption of ammonia. The experimental results further show that additional adsorption sites exist for ammonia on the iron phthalocyanine monolayer

Pyridine Adsorption on Single-Layer Iron Phthalocyanine on Au(111)

The adsorption of pyridine on monolayers of well-ordered, flat-lying iron phthalocyanine molecules on Au(111) is investigated by X-ray photoelectron spectroscopy, X-ray absorption spectroscopy, and density functional theory. It is found that pyridine both coordinates to the iron site of iron phthalocyanine and binds weakly to other sites. The iron coordination causes significant changes in the electronic structure of the iron phthalocyanine compound, with the implication of a change of the spin properties of the iron atoms due to the strong ligand field created by the pyridine axial ligand. Both low coverages and multilayer coverages of pyridine are considered. At low doses, the pyridine molecules are ordered, whereas in multilayers, no preferred orientation is observed. The orientation of the FePc molecules with respect to the Au(111) surface is not affected by the adsorption of pyridine