STARK EFFECT IN ACETALDEHYDE: RELATIVE SIGN OF DIPOLE COMPONENTS

Author Institution: Laboratory for Physical Chemistry, ETH, Universit\""{a}tstrAccurate expectation values of the electric dipole operator for molecules with a symmetric internal rotor have been calculated using a semirigid model. Whereas the contributions from dipole components along the principal axes are completely separated for a rigid rotor, they are mixed appreciably for molecules with resolved internal rotation splittings. Combinations with different relative signs of the dipole components lead to different expectation values. This is demonstrated for acetaldehyde $(CH_{3}CHO)$ through the effect on the Stark splittings. Several transitions including excited torsional states have been analyzed and the relative signs of the dipole components have been determined

THE MEASUREMENT AND INTERPRETATION OF T1T_{1}, AND T2T_{2} IN THE INVERSION DOUBLETS OF 15NH3^{15}NH_{3} AND THE ROTATIONAL TRANSITIONS IN OCS

This work was supported by the Army Research Office, Grant No. DAHCO 4 74 G 0034.Author Institution: Noyes Chemical Laboratory, University of IllinoisTransient experiments have been completed to measure $T_{1}$ and $T_{2}$ as a function of pressure for the inversion transitions in several (J, K, |M| = J) states in $^{15}NH_{3}$ and in the J = 1 $\rightarrow$ J = 2, $M = \pm 1$ transitions in OCS. In OCS, $T_{1} = T_{2}$ for both the $J = O \rightarrow J = 1, M = O$ and $J = 1 \rightarrow J = 2$, $M =\pm 1$ transitions. In $NH_{3}$, however, the ratio $T_{2}/T_{1}$ varies over the range $1.0 \leq T_{2}/T_{1} \leq 2$. These results are interpreted using a modified form for the Anderson theory of line broadening. Comparisons are made between the results of this work and earlier steady state double resonance work

Building materials and construction:Constructing a quality of life

\u3cp\u3eCatastrophes and new societal ambitions energized the huge construction effort undertaken between 1910 and 1970. The floods of 1917 and 1953 led to enormous investments in coastal defences. The government also undertook major investments in the construction of roadways and other infrastructural works. New building codes, damage incurred during the Second World War and population growth incited new housing construction on a colossal scale. Demand for building materials grew apace. The need for wood and mineral subsoil resources transformed nature and landscapes in the Netherlands and at foreign sites. Dutch forestry practices were rationalised. Imports from the Baltic regions by and large met the Dutch demand for wood. But the creation of monocultures and production forests in these regions reduced local biodiversity. Gravel and marl were mined above all in the province of Limburg. That led to tensions with local stakeholders. Gravel extraction transformed the floodplains of the Meuse into a lake landscape. It led directly to the Excavation Law, the first environmental law in the area of land-use. After 1970, regulations concerning land-use and new landscape values would regularly inspire conflicts in the national supply of building materials (see Chap. 19).\u3c/p\u3

Novel multispecies microbial consortia involved in lignocellulose and 5-hydroxymethylfurfural bioconversion

To develop a targeted metagenomics approach for the analysis of novel multispecies microbial consortia involved in the bioconversion of lignocellulose and furanic compounds, we applied replicated sequential batch aerobic enrichment cultures with either pretreated or untreated wheat straw as the sources of carbon and energy. After each transfer, exponential growth of bacteria was detected using microscopic cell counts, indicating that the substrate was being utilized. In batch, the final bacterial abundances increased from an estimated 5 to 8.7-9.5 log 16S rRNA gene copy numbers/ml. The abundances of fungal propagules showed greater variation, i.e., between 5.4 and 8.0 log ITS1 copies/ml. Denaturing gradient gel electrophoresis analyses showed that the bacterial consortia in both treatments reached approximate structural stability after six transfers. Moreover, the structures of the fungal communities were strongly influenced by substrate treatment. A total of 124 bacterial strains were isolated from the two types of enrichment cultures. The most abundant strains were affiliated with the genera Raoultella/Klebsiella, Kluyvera, Citrobacter, Enterobacter, Pseudomonas, Acinetobacter, Flavobacterium and Arthrobacter. Totals of 43 and 11 strains obtained from the untreated and pretreated substrates, respectively, showed (hemi)cellulolytic activity (CMC-ase and xylanase), whereas 96 strains were capable of growth in 7.5 mM 5-hydroxymethylfurfural. About 50 % of the latter showed extracellular oxidoreductase activity as detected by a novel iodide oxidation method. Also, (hemi)cellulolytic fungal strains related to Coniochaeta, Plectosphaerella and Penicillium were isolated. One Trichosporon strain was isolated from pretreated wheat straw. The two novel bacterial-fungal consortia are starting points for lignocellulose degradation applications