Struktur und Aufbau moderner Analyse-Meßeinrichtungen

Structure and modular nature of modern analytical measuring equipment . Modern analytical instrumentation exhibits excellent adaptability to a wide range of demands arising from the process concerned and the site of application. Optimization of the specific plant structure according to criteria such as performance data, reliability, and economic factors demands a versatile modular system of components for matching the sensors to the process, the process control system, the discharge locations, and the environment. In addition, functions such as handling, control, and monitoring are steadily increasing in importance.     

Die Bedeutung der Chemietechnik für fortgeschrittene Technologien zur Stromerzeugung

Significance of chemical engineering for advanced power generation technologies . The demands placed on power plant engineers have altered with the introduction of advanced technologies of power generation, with the classical physical areas of work being increasingly augmented by tasks requiring considerable knowledge of chemical engineering. This change began with the introduction of the desulphurization of flue gases in fossil-fuel fired power plant and continued steadily with the further development of environmental protection requirements. In addition, demands for reduction of emission in connection with high fuel prices led to the development of new power plant technologies permitting better utilization of input energy. With the aid of examples taken from the whole field of advanced powerplant technology and which range from development and design of non-polluting and more efficient power plant processes to questions of disposal of power plant by-products it is shown to what extent conventional powerplant engineering is pervaded by chemical engineering questions.     

Bindungsformen des Schwefels in Hochofenschlacken

Verhalten der Nebenbestandteile bei der Erstarrung von Hochofenschlacken. Beobachtungen bei der Wasserauslaugung von Schlacken. Sulfidphasen und deren Zusammensetzung. Die Bedeutung der Alkalien für die Bildung von Sulfiden und den Eisenzerfall von Schlacken. Thermodynamische Folgerungen.     

Strömung und Wärmeübergang in Schüttungen mit rotationssymmetrischen Oberflächenprofilen und Kornverteilungen

Theoretische Berechnung der Geschwindigkeits- und Gasdruckverteilung in Schüttungen. Gemessene Gasdruckverteilung und Folgerungen für die Strömungsverhältnisse. Messung von Geschwindigkeitsprofilen über Schüttungen mit verschiedenen rotationssymmetrischen Oberflächenprofilen; Abhängigkeit von der mittleren Höhe, vom Oberflächenprofil und von der Korngröße der Schüttung sowie vom Winddurchsatz. Anwendung auf die Strömung im Hochofen. Strömungsmessungen im Schüttungsinneren.     

Korrosionsverhalten austenitischer Stähle bei der Prüfung nach Huey in Abhängigkeit vom Verformungsgrad

Einfluß von Probenlage und Verhältnis Querschnittsflächen/Gesamtfläche sowie Verformungsgrad beim Schmieden auf die Massenverlustrate bei der Prüfung des Stahles X 2 CrNiMoN 18 13 auf Beständigkeit gegen Kornzerfall nach Huey. Bedeutung von Zeilenbreite und Ausmaß der Seigerungen der Legierungselemente sowie Ableitung einer Beziehung zur Beherrschung der Beständigkeit gegen Kornzerfall.     

Ermittlung der zum Überlaufen von Sauerstoffaufblaskonvertern führenden Aufblasgeschwindigkeiten sowie der Größe fluider Partikeln in Gasströmen

Analogien zwischen dem Schäumen im Sauerstoffaufblaskonverter und dem Verhalten von Wirbelschichten. Quantitative Untersuchung der Höhe der Schaumschlacke. Aufstellung eines Nomogramms zur Ermittlung der Schaumschlackenhöhe bei Vorgabe der Sauerstoffaufblasgeschwindigkeit oder umgekehrt. Angabe von Maßnahmen zur Verminderung der Gefahr des Überlaufens. Abschätzung der Partikelabmessungen unter Berücksichtigung von Gasströmen als Zerkleinerungsmittel. Erörterung des Einflusses des entweichenden Kohlenmonoxids auf die Größe der fluiden Tropfen in der Schaumschlacke. Aussagen über bei Blasbeginn durch den Sauerstoffstrahl erzeugte Partikeln, deren Größe mit denen des braunen Rauches vergleichbar ist. Die Erzeugung der ?richtigen? Größe der Fluidpartikeln in der Schaumschlacke als Optimierungsproblem.     

Characterization and properties of metallic iron nanoparticles: spectroscopy, electrochemistry, and kinetics

There are reports that nano-sized zero-valent iron (Fe0) exhibits greater reactivity than micro-sized particles of Fe0, and it has been suggested that the higher reactivity of nano-Fe0 may impart advantages for groundwater remediation or other environmental applications. However, most of these reports are preliminary in that they leave a hostof potentiallysignificant(and often challenging) material or process variables either uncontrolled or unresolved. In an effort to better understand the reactivity of nano-Fe0, we have used a variety of complementary techniques to characterize two widely studied nano-Fe0 preparations: one synthesized by reduction of goethite with heat and H2 (Fe(H2)) and the other by reductive precipitation with borohydride (Fe(BH)). Fe(H2) is a two-phase material consisting of 40 nm alpha-Fe0 (made up of crystals approximately the size of the particles) and Fe3O4 particles of similar size or larger containing reduced sulfur; whereas Fe(BH) is mostly 20-80 nm metallic Fe particles (aggregates of <1.5 nm grains) with an oxide shell/coating that is high in oxidized boron. The FeBH particles further aggregate into chains. Both materials exhibit corrosion potentials that are more negative than nano-sized Fe2O3, Fe3O4, micro-sized Fe0, or a solid Fe0 disk, which is consistent with their rapid reduction of oxygen, benzoquinone, and carbon tetrachloride. Benzoquinone-which presumably probes inner-sphere surface reactions-reacts more rapidly with FeBH than Fe(H2), whereas carbon tetrachloride reacts at similar rates with FeBH and Fe(H2), presumably by outer-sphere electron transfer. Both types of nano-Fe0 react more rapidlythan micro-sized Fe0 based on mass-normalized rate constants, but surface area-normalized rate constants do not show a significant nano-size effect. The distribution of products from reduction of carbon tetrachloride is more favorable with Fe(H2), which produces less chloroform than reaction with Fe(BH).     

Gamma irradiation of cowpea (Vigna unguiculata L. Walp) flours and pastes: Effects on functional,thermal and molecular properties of isolated proteins

In a previous study irradiation of cowpea flours and pastes at medium (10 kGy) and high (50 kGy) doses resulted in significant changes in protein-related functional properties. To understand some of the effects of gamma irradiation on cowpea proteins in particular, we isolated proteins from cowpea flours (FPC) and pastes (PPC) treated with gamma irradiation at 2, 10, and 50 kGy and analyzed their functional, thermal and molecular properties. Nitrogen solubility index of both FPC and PPC decreased, whereas oil absorption and emulsion capacities increased significantly with increasing irradiation dose. Differential scanning calorimetry showed decreases in transition temperatures (T_d) and enthalpies (ΔH), indicating a progressive denaturation of cowpea proteins with increasing irradiation. Size exclusion HPLC revealed increases in protein molecular weights, probably due to protein–protein cross-linking with irradiation in a dose-dependent manner. Reducing SDS-PAGE of FPC and PPC samples seems to suggest that the contribution of disulphide bonds to irradiation-induced cowpea protein–protein cross-linking is small.     

Advanced solid-state NMR characterization of marine dissolved organic matter isolated using the coupled reverse osmosis/electrodialysis method

Advanced (13)C solid-state techniques were employed to investigate the major structural characteristics of two surface-seawater dissolved organic matter (DOM) samples isolated using the novel coupled reverse osmosis/electrodialysis method. The NMR techniques included quantitative (13)C direct polarization/magic angle spinning (DP/MAS) and DP/MAS with recoupled dipolar dephasing, (13)C cross-polarization/total sideband suppression (CP/TOSS), (13)C chemical shift anisotropy filter, CH, CH(2), and CH(n) selection, two-dimensional (1)H-(13)C heteronuclear correlation NMR (2D HETCOR), 2D HETCOR combined with dipolar dephasing, and (15)N cross-polarization/magic angle spinning (CP/MAS). The two samples (Coastal and Marine DOM) were collected at the mouth of the Ogeechee River and in the Gulf Stream, respectively. The NMR results indicated that they were structurally distinct. Coastal DOM contained significantly more aromatic and carbonyl carbons whereas Marine DOM was markedly enriched in alkoxy carbon (e.g., carbohydrate-like moieties). Both samples contained significant amide N, but Coastal DOM had nitrogen bonded to aromatic carbons. Our dipolar-dephased spectra indicated that a large fraction of alkoxy carbons were not protonated. For Coastal DOM, our NMR results were consistent with the presence of the major structural units of (1) carbohydrate-like moieties, (2) lignin residues, (3) peptides or amino sugars, and (4) COO-bonded alkyls. For Marine DOM, they were (1) carbohydrate-like moieties, (2) peptides or amino sugars, and (3) COO-bonded alkyls. In addition, both samples contained significant amounts of nonpolar alkyl groups. The potential sources of the major structural units of DOM were discussed in detail. Nonprotonated O-alkyl carbon content was proposed as a possible index of humification.