Auflistung nach Schlagwort "540 - Chemie"

Gerade angezeigt 1 - 20 von 34

„AppLaus“: App-Entwicklung in der Lehramtsausbildung
(Universität Regensburg, 2018) Arnold, Julia; Mahler, Daniela; Mühling, Andreas; Maurer, Christian
04B - Beitrag Konferenzschrift
Biological properties of extracellular vesicles and their physiological functions
(Taylor & Francis, 14.05.2015) Lipps, Georg
01A - Beitrag in wissenschaftlicher Zeitschrift
Boosting light harvesting and charge separation over hollow double-shelled Ag@SrTiO3-TiO2 with Z-scheme heterostructure for highly efficient photocatalytic reduction of nitrate to N2
(Elsevier, 01.02.2023) Zhang, Yixuan; Liu, Cong; Zhou, Ye; Wang, Jinnan; Li, Aimin; Corvini, Philippe
01A - Beitrag in wissenschaftlicher Zeitschrift
Carbon mass determinations during the AIDA soot aerosol campaign 1999
(Elsevier, 10/2003) Saathoff, Harald; Naumann, Karl-Heinz; Schnaiter, Martin; Schöck, Werner; Weingartner, Ernest; Baltensperger, Urs; Krämer, Lutz; Bozoki, Zoltan; Pöschl, Ulrich; Niessner, Reinhard; Schurath, Ulrich
During the soot aerosol campaign particle carbon mass concentrations of Diesel soot, spark generated “Palas” soot, external and internal mixtures of Diesel soot with (NH4)2SO4, and particles coated with secondary organic aerosol material were determined by several different methods. Two methods were based on thermochemical filter analysis with coulometric and NDIR detection of evolved CO2 (total carbon, TC and elemental carbon, EC) and four methods employed optical techniques: aethalometry (black carbon, BC), photoacoustic soot detection (BC), photoelectron emission, and extinction measurement at 473 nm. Furthermore, β-attenuation (total particulate mass), FTIR spectroscopy (sulphate), and COSIMA model calculations were used to determine particle mass concentrations. The general agreement between most methods was good although some methods did not reach their usual performance. TC determined by coulometric filter analysis showed good correlations with optical extinction, photoacoustic BC signal, and photoelectron emission data. However, the evolution of the photoelectron emission signal correlated with changes in accessible surface area rather than mass concentration and was very sensitive to surface conditions. The BC content as measured by the aethalometers approximately equal to less than 70% of the EC content for Diesel soot and amounts to less than 25% of the EC content of “Palas” soot.
01A - Beitrag in wissenschaftlicher Zeitschrift
Characterization of size-fractionated aerosol from the Jungfraujoch (3580 m asl) using total reflection x-ray fluorescence (TXRF)
(Taylor & Francis, 22.09.2000) Streit, Niklaus; Weingartner, Ernest; Zellweger, Christoph; Schwikowski, Margit; Gäggeler, Heinz W.; Baltensperger, Urs
During three field campaigns at the Jungfraujoch High Alpine Research Station, Switzerland, size-fractionated aerosol was collected using a cascade impactor. The particles were impacted on silicon oil-coated quartz sampling substrates. The actual analysis was then performed directly on these quartz sampling substrates using total reflection X-ray fluorescence. The resulting size distributions of 16 elements (S, Cl, K, Ca, Ti, Mn, Fe, Cu, Zn, Se, Br, Rb, Sr, Y, Zr, Pb) were investigated to determine the best cut-off diameter to distinguish between geogenic and anthropogenic particles. The obtained cut-off diameter of 1 μm is an important parameter in the current world-wide measurements under the auspices of the World Meteorological Organization's Global Atmosphere Watch aerosol project.
01A - Beitrag in wissenschaftlicher Zeitschrift
Chemische Sachverhalte in der Primarstufe? Ein Beispiel aus dem mobilen Lernlabor MobiLab
(Schneider Verlag Hohengehren, 2017) Beerenwinkel, Anne; Till, Maria; Favre, Pascal; Mathis, Christian
04A - Beitrag Sammelband
Cytotoxic effects of pentachlorophenol (PCP) and its metabolite tetrachlorohydroquinone (TCHQ) on rainbow trout liver cells are modulated by antioxidants
(Springer, 05.07.2014) Pietsch, Constanze; Hollender, Juliane; Burkhardt-Holm, Patricia; Dorusch, Falk
Abstract The world-wide distribution and high bioaccumulation potential of pentachlorophenol (PCP) in aquatic organisms imply a high toxicological impact in aquatic systems. Firstly, our investigations show that, similar to mammalian cell lines, PCP can be metabolized to tetrachlorohydroquinone (TCHQ) in the permanent cell line derived from rainbow trout liver cells (RTL W-1). Moreover, we demonstrate that PCP as well as its metabolite TCHQ is capable of influencing the viability of these cells. Three cell viability assays were performed to assess possible cellular targets of these substances. Thus, the toxicity of the PCP-derivative TCHQ was shown for the first time in a fish cell line. Further investigations revealed the involvement of ROS in the cytotoxicity of PCP and its metabolite TCHQ. The observation of oxidative stress due to PCP or TCHQ exposure does provide a plausible explanation for the increased cytotoxicity of higher concentrations of both substances and implies possible mechanisms underlying these observations. In addition, antioxidants such as ascorbic acid and quercetin modulate the detrimental effects of PCP and TCHQ whereby both compounds exacerbate the cytotoxic effects of high PCP and TCHQ concentrations.
01A - Beitrag in wissenschaftlicher Zeitschrift
Diagnose und Förderung von Kompetenzen im Bereich Erkenntnisgewinnung mit Aufgaben zum «effektbasierten Vergleichen»
(Wiley, 2018) Hild, Pitt; Metzger, Susanne; Parchmann, Ilka
Dieser Artikel liefert konkrete Beispiele zur Beurteilung und Förderung experimenteller Kompetenzen im Bereich Erkenntnisgewinnung. Es werden zunächst Grundlagen für die Entwicklung kompetenzorientierter hands-on Experimentieraufgaben am Beispiel des „effektbasierten Vergleichens“ beschrieben. Bei diesen Aufgaben mgssen Schülerinnen und Schüler unterschiedliche Objekte anhand einer gegebenen Eigenschaft experimentell vergleichen. Unterschiedliche zu erreichende Kompetenzen aus dem Bereich der Erkenntnisgewinnung wurden a priori, anhand eines Strukturmodells, postuliert. Mithilfe validierter Testaufgaben und eines standardisierten Kodiermanuals konnte bei einer Stichprobe von 418 12- bis 15-jährigen Schülerinnen und Schülern (jeweils 2 Aufgaben mit gleichem Aufgabenstamm pro Person) eine Progression entlang dieser Kompetenzen nachgewiesen werden. Die Uebereinstimmungen zwischen den jeweiligen Kodiererinnen und Kodierern liegen alle in einem akzeptablen bis sehr guten Bereich. Die Ergebnisse sollen die Grundlage für die Konstruktion von Lernumgebungen liefern, die es den Lehrpersonen erlauben, Kompetenzen im Bereich der Erkenntnisgewinnung zu messen und individuell zu fördern.
01A - Beitrag in wissenschaftlicher Zeitschrift
Die Chemie Pilotanlage der FHNW Muttenz
(25.04.2023) Zogg, Andreas; Asprion, Jonas
Der Verein Miniplant 4.0 entwickelt im Process Technology Center an der FHNW neuartige Chemie-Pilotanlagen im Miniplant-Massstab. Der zentrale Scale-Down-Reaktor dient der präzisen Prozessentwicklung im Rührkessel. Insbesondere werden darin die lokalen thermischen Verhältnisse des Produktionsreaktors durch den Einsatz eines speziell designten Wärmetauschers exakt nachgebildet. Damit wird den Studenten und lokalen Unternehmen ein neuartiges Entwicklungswerkzeug zur Verfügung gestellt, welches einen schnelleren und präziseren Scale-Up von Produktionsverfahren direkt aus dem Labormassstab in den Produktionsreaktor erlaubt. Herr Prof. Dr. Andreas Zogg von der FHNW in Muttenz zeigt Ihnen den aktuellen Status der Anlage und die vielseitigen Schulungs- und Forschungsmöglichkeiten. Unterstützt wird er durch Herrn Dr. Jonas Asprion von der Firma Tool-Temp AG, welche die Kommerzialisierung der Temperierlösungen für Reaktormantel und Wärmetauscher anstrebt.
06 - Präsentation
Dynemicin analogs: Syntheses, methods of preparation and use
(United States Patent and Trademark Office, 04.01.1994) Smith, Adrian L.; Hwang, Chan-Kou; Wendeborn, Sebastian; Nicolaou, Kyriacos C.; Schreiner, Erwin P.; Stahl, Wilhelm; Dai, Wei-Min; Maligres, Peter E.; Suzuki, Toshio
A fused ring system compound is disclosed that contains an epoxide group on one side or the fused rings and an enediyne macrocyclic ring on the other side of the fused rings. The compounds have DNA-cleaving, antimicrobial and tumor growth-inhibiting properties. Chimeric compounds having the fused ring system compound as an aglycone bounded to (i) a sugar moiety as the ogligosaccharide portion or(ii) a monoclonal antibody or antibody combining site portion thereof that immunoreacts with target tumor cells are also disclosed. Compositions containing a compound or a chimer are disclosed, as are methods or preparing a compound.
12 - Patent
Effect of printing parameters on mechanical performance of material-extrusion 3D-printed PEEK specimens at the point-of-care
(MDPI, 17.01.2023) Zarean, Paridokht; Zarean, Parichehr; de Wild, Michael; Thieringer, Florian M.; Sharma, Neha; Seiler, Daniel; Malgaroli, Patrick
Additive manufacturing (AM) of polyetheretherketone (PEEK) biomaterials using the material-extrusion (MEX) method has been studied for years. Because of the challenging manufacturing process, precisely controlling printing parameters is crucial. This study aimed to investigate the effects of printing parameters such as orientation and position of printing on mechanical properties. Thus, 34 samples were printed using PEEK filament and the MEX process. Samples were divided into two main groups (A,B) according to their printing orientations (A: groups 1–3) and positions on the build plate (B: groups 4–8). Mechanical tensile tests were performed to evaluate the effects of different printing orientations and positions on mechanical properties. The means of the tensile modulus in samples 3D-printed in XY (group 1), XZ (group 2), and ZX (group 3) orientations were not significantly different (p-value = 0.063). Groups 1 and 2 had smaller distributions than group 3 in the means of tensile strength. The t-test showed that the overall means of the measurements in groups 4–8 did not differ significantly (p-value = 0.315). The tensile tests indicated that printing in vertical and horizontal orientations had no significant influence on mechanical properties. There were no significant differences in mechanical strength between top/bottom printed samples in five different lateral positions. Reliability of printing with good mechanical properties could be a step forward to manufacturing patient-specific implants.
01A - Beitrag in wissenschaftlicher Zeitschrift
Efficient catalytic ozonation over Co-ZFO@Mn-CN for oxalic acid degradation. Synergistic effect of oxygen vacancies and HOO-Mn-NX bonds
(Elsevier, 03/2023) Xu, Menglu; Zhang, Yibing; Yin, Huaqin; Wang, Jinnan; Li, Aimin; Corvini, Philippe
01A - Beitrag in wissenschaftlicher Zeitschrift
Empfehlung zum Vorgehen bei Radonsanierungen
(06.12.2013) Dorusch, Falk
06 - Präsentation
Enantiomeric dynemicin analogs, preparation and use thereof
(World Intellectual Property Organization, 25.11.1993) Smith, Adrian L.; Wendeborn, Sebastian; Nicolaou, Kyriacos; Schreiner, Erwin P.; Dai, Wei-Min; Susuki, Toshio
An enantiomer of a fused ring system compound is disclosed that contains an epoxide group on one side of the fused rings and an enediyne macrocyclic ring on the other side of the fused rings. The enantiomeric compounds have DNA-cleaving, antimicrobial and tumor growth-inhibiting properties that are enhanced over their racemates. Chimeric compounds having the enantiomeric fused ring system compound as an aglycone bonded to (i) a sugar moiety as the oligosaccharide portion or (ii) a monoclonal antibody or antibody combining site portion thereof that immunoreacts with target tumor cells are also disclosed. Compositions containing an enatiomeric compound or an enantiomeric chimer are disclosed, as are methods of preparing an enantiomeric compound.
12 - Patent
Heterogeneous chemical processing of 13NO2 by monodisperse carbon aerosols at very low concentrations
(American Chemical Society, 19.09.1996) Kalberer, Markus; Tabor, K.; Ammann, Markus; Parrat, Yves; Weingartner, Ernest; Piguet, D.; Rössler, E.; Jost, Dieter T.; Türler, Andreas; Gäggeler, Heinz W.; Baltensperger, Urs
The heterogeneous reaction of NO2 with different carbon aerosol particles was investigated in situ. The NO2 was labeled with the β+-emitter 13N (half-life 10.0 min) which allowed application of NO2 at very low concentrations. The carbon aerosol was either produced by a spark discharge generator using graphite electrodes or by a brush generator resuspending commercial soot material. Monodisperse size cuts between 50- and 490-nm diameter were selected and mixed with the 13NO2. After a defined reaction time, the different reaction products were separated by means of selective traps and detected on-line by γ-spectrometry. A sticking coefficient for chemisorption of NO2 between 0.3 × 10ˉ⁴ and 4.0 × 10ˉ⁴ and a rate constant for the reduction of adsorbed NO2 to NO(g) between 4.0 × 10 ˉ⁴ and 9.4 × 10 ˉ⁴ /s were determined for both aerosols. The sticking coefficient obtained in this study in situ with aerosol particles is 2 orders of magnitudes smaller than the uptake coefficient recently reported with bulk carbon material.
01A - Beitrag in wissenschaftlicher Zeitschrift
Hygroscopic properties of carbon and diesel soot particles
(Elsevier, 08/1997) Weingartner, Ernest; Burtscher, Heinz; Baltensperger, Urs
Laboratory experiments were performed in order to study the hygroscopic properties of freshly produced carbon and diesel soot particles at subsaturations (i.e. at relative humidity < 100%). Wetted carbon aggregates collapsed to a more compact structure. In contrast, the diesel combustion particles exhibited a much smaller restructuring combined with condensational growth. The hygroscopicity of the diesel particles was enhanced when the sulfur content of the fuel was increased or when the particles were subjected to an ozone and UV pre-treatment. By extrapolating the data with a Köhler model critical supersaturations were calculated. Freshly emitted combustion particles are unlikely to act as cloud condensation nuclei whereas an aging of the particles will enhance their nucleation ability.
01A - Beitrag in wissenschaftlicher Zeitschrift
Influence of pulping conditions on the pulp yield and fiber properties for pulping of spruce chips by deep eutectic solvent
(Springer, 2023) Pérez, Alan; Roy, Yagnaseni; Rip, Constantijn; Kersten, Sascha R. A.; Schuur, Boelo
The chemical pulping of wood chips using deep eutectic solvents (DES-pulping) has emerged as an alternative technology to conventional pulping in the paper industry, allowing the production of pulp in combination with the recovery of lignin and sugars for valorization. A challenge in the development of this technology is the understanding of how the operating conditions influence the crucial pulp manufacturing parameters such as delignification percentage, pulp yield, and fiber quality. This work is focused on investigating the effect of operating conditions such as cooking temperature, cooking time, liquor-to-wood ratio, initial water content on DES, type of mixing, the addition of a pre-treatment step (pre-impregnation of DES into the wood chips) to cooking process, and DES composition (lactic acid:choline chloride, lactic acid:sodium chloride, and lactic acid:sodium bromide) on the cooking of wood chips by DES. A shortcut quality evaluation parameter (Q), defined as the product of the fiber length and the degree of delignification quantified the quality of the pulping process in a single value, shows values similar to a reference unbleached kraft pulp for cooking at 130 °C in a range of cooking times from 3 to 4.5 h at a L/W of 10:1 by using lactic acid:choline chloride DES. More elaborate property analysis on the fibers showed that several of the the quality-indicating properties of the fibers (coarseness, shape factor, fibril area, and crill index) are comparable with typical sulfite pulping fibers.
01A - Beitrag in wissenschaftlicher Zeitschrift
Integration of a liquid membrane in Taylor flow regime with a fermentation by Lactobacillus casei ATCC 393 for in-situ lactic acid removal
(Elsevier, 06/2019) Pérez, Alan; Rodríguez-Barona, Sneyder; Fontalvo, Javier
A new type of liquid membranes called liquid membrane in Taylor flow was integrated to a lactic acid fermentation, using Lactobacillus casei ATCC 393, for lactic acid removal during fermentation. The performance in terms of lactic acid production of the hybrid batch system is compared to a conventional batch fermentation. Lactic acid removal rate increases proportionally with the LA concentration within the fermenter. The lactic acid, the biomass production and the LA productivity in the hybrid system increased by 41.8, 12 and 26.6%, respectively, as compared to the conventional batch fermentation. However, toxicity effects reduce LA to glucose yield in 15.9% as compared to conventional fermentation. Liquid membranes in Taylor flow results promising for enhancing batch and continuous fermentation processes by a hybrid system.
01A - Beitrag in wissenschaftlicher Zeitschrift
Intelligente Trocknung
Liquid extraction with immobilized liquids for product recovery from fermentation broths
(Elsevier, 2022) Pérez, Alan; Gössi, Angelo; Riedl, Wolfgang; Schuur, Boelo; Fontalvo, Javier; Thatoi, Hrudayanath; Mohapatra, Sonali; Das, Swagat Kumar
Nowadays, many fermentation chemicals are produced at an industrial scale. Numerous technological improvements have been developed and implemented to achieve high quality and quantity of fermentation products. However, several drawbacks in fermentation processes still limit their application at an industrial level. In situ product removal (ISPR) is a potential alternative to overcome the conventional drawbacks of the fermentative processes, increasing the fermentation's productivity and reducing the separation steps for recovery and purification. Currently, liquid extraction has emerged as a promising separation technology for ISPR, with immobilized liquids such as membrane-assisted extraction and microchannel liquid membrane, due to the high mass transfer rates, scalability, easy integration, and efficiency. This chapter will discuss these technologies regarding their integration into fermentative processes.
04A - Beitrag Sammelband