Phase Transformations and Grain Growth in β-stabilized TiAl Alloys

Solid-state phase transformations and grain growth of an intermetallic γ-TiAl alloy were investigated in-situ using high-temperature laser scanning confocal microscopy (HTLSCM). During isothermal annealing in the single β-phase region, significant grain coarsening was observed. On cooling beneath the β-transus temperature with different rates, a CCT diagram was evaluated for the initiation of β to α phase transformation and changes in the morphology were observed.     

Bis-(1-chlor-3-phenoxy-prop-2-yl)-sulfane – Nucleophile Substitution und Regiochemie,Diastereomerentrennung und -zuordnung. Synthese diastereomerenreiner Trithiacyclen

Bis-(1-chloro-3-phenoxy-prop-2-yl)-sulfanes – Nucleophilic Displacement and Regiochemistry. Separation and Assignment of Diastereomers. Synthesis of Diastereomerically Pure Trithiacycles The title compounds 1 were substituted by a series of O-, N- and S-nucleophiles (H₂O solvolysis, AgOAc, NaN₃, KSCN, NaSPh, thiourea). A strong tendency to β-elimination of HCl depending on the kind of the attacking nucleophile was found. In most cases no regioisomerization could be detected in the isolated products of the nucleophilic displacement. Best results were obtained with sulfur nucleophiles. The separation of the diastereomeric mixture of the p-kresyl derivative 1b into the individual diastereomers 1bA and 1bB in a preparative scale was achieved. These 3-thia-1,5-dichlorides and several products of substitution could be assigned to the meso- or (±)-form by examination of the stereochemistry and symmetry of the corresponding sulfoxides. The 1,5-dimercapto derivatives 8 are convenient as structural units for the synthesis of diastereomerically pure cis- or trans-disubstituted trithiacycles e.g. 15bA , 15bB . The (±)-form of the 4,6-disubstituted 2,5,8-trithia[9]-(2,6)-pyridinophane 16bA was characterized by X-ray crystal structure determination.     

Solution of nonlinear time-variant systems with random inputs

The adjoint method of analysis and Booton's equivalent-gain technique for nonlinearities can be combined, using a successive-approximation method, to analyse nonlinear time-varying systems where the input is random. The solution is performed on an analogue computer. Logic control of the computer speeds the calculation.     

<Emphasis Type="Italic">Zea Mays</Emphasis>: Benzoxazolinone Detoxification Under Sulfur Deficiency Conditions—A Complex Allelopathic Alliance Including Endophytic <Emphasis Type="Italic">Fusarium Verticillioides</Emphasis>

Benzoxazolinone detoxification is similar in plants grown under sulfur deficiency conditions and in control plants grown with an optimal S supply. However, when S-deficient plants were treated with metolachlor before benzoxazolin-2(3H)-one (BOA) incubation, detoxification was reduced, as indicated by a lower accumulation of the detoxification products BOA-6-O-glucoside and glucoside carbamate and by a loss of BOA-6-OH glucosyltransfease activity. Root colonizing microorganisms and the endophytic fungus Fusarium verticillioides participated in benzoxazolinone detoxification by converting the compound to 2-acetamidophenol (AAP) or O-hydroxyphenyl malonamic acid (OHPMA), a process accompanied by the appearance of phenoxazinone. Maize roots, however, absorbed AAP and OHPMA only in traces. Absorbed traces of OHPMA stimulated maize radicle growth, and traces of AAP stimulated cress. Phenoxazinone inhibited the growth of cress radicles at concentrations higher than 500 μM, whereas maize radicles were hardly affected. F. verticillioides did not convert benzoxazolinone to any known microbial degradation product when the medium of maize seedlings was inoculated with the fungus under sterile condition. Plant–fungus interactions seem to be important in plant survival of allelopathic attacks. This study points to a complicated network of allelopathic interactions that are influenced by biotic and abiotic factors, including herbicides.     

Operational window of a deammonifying sludge for mainstream application in a municipal wastewater treatment plant

The present work aimed to study the mainstream feasibility of the deammonifying sludge of side stream of municipal wastewater treatment plant (MWWTP) in Kaster, Germany. For this purpose, the deammonifying sludge available at the side stream was investigated for nitrogen (N) removal with respect to the operational factors temperature (15–30°C), pH value (6.0–8.0) and chemical oxygen demand (COD)/N ratio (≤1.5–6.0). The highest and lowest N-removal rates of 0.13 and 0.045 kg/(m³ d) are achieved at 30 and 15°C, respectively. Different conditions of pH and COD/N ratios in the SBRs of Partial nitritation/anammox (PN/A) significantly influenced both the metabolic processes and associated N-removal rates. The scientific insights gained from the current work signifies the possibility of mainstream PN/A at WWTPs. The current study forms a solid basis of operational window for the upcoming semi-technical trails to be conducted prior to the full-scale mainstream PN/A at WWTP Kaster and WWTPs globally.     

Hohlfaser-Membrankontaktoren zur Stickstoffrückgewinnung aus Prozesswasser einer kommunalen Kläranlage

Process water deriving from digested sludge dewatering at municipal wastewater treatment plants (WWTP) represents an additional load for the plant in terms of nitrogen. Münster WWTP is the first German plant to operate an innovative full-scale membrane contactor facility for nitrogen removal and recovery from process water. Within the scope of this study, aspects influencing the membrane performance and operation as well as utilization of the produced fertilizer are investigated. First results reveal nitrogen removal efficiencies around 85 % and a regional usability of the produced fertilizer.     

Katalysatorrecycling in der homogenkatalysierten Kreuzmetathese von Ölsäuremethylester und 4‐Octen

The recycling of homogeneous metathesis catalysts is a big challenge in alkene metathesis. Within this contribution the recycling of these catalysts is investigated in the cross metathesis of methyl oleate and 4‐octene as model reaction. Fluid‐fluid separation technique and temperature dependent solvent systems allow the separation of the homogeneously solved catalysts from the metathesis products. The catalyst phase was successfully recycled in multiple recycling runs only with minor loss of yield.