ALBERT

Notes: The far-infrared transmission of polycrystalline C60 and C70 compacts has been measured from 3 to 330 cm−1 as a function of temperature. Both intrinsic and impurity-induced absorption bands are identified in these samples. The low temperature phase of C60 is observed to have two infrared active translational modes at 40.9 and 54.7 cm−1. Samples of C60 exposed to air before cooling to low temperatures contain several additional infrared bands which have been identified with adsorbed H2O vapor. A large isotope shift is observed for some of the bands when H2O is replaced by D2O, consistent with rotational or librational behavior. For C70 one strong intrinsic band is centered at 21 cm−1 and four much weaker bands occur at 28, 32, 52, and 64 cm−1. When doped with H2O vapor, C70 also produces several strong H2O impurity bands, some of which show isotopic shifts. The temperature dependence of five intramolecular C70 modes in the frequency range from 200 to 330 cm−1 is also reported.

Notes: Stand density reductions have been proposed as a method by which old-growth ponderosa pine (Pinus ponderosa) forests of North America can be converted back to pre-1900 conditions, thereby reducing the danger of catastrophic forest fires and insect attacks while increasing the productivity of the remaining old-growth individuals. However, the duration of productivity response of individual trees and the physiological mechanisms underlying such a response remain speculative issues, particularly in old trees. Tree-ring measurements of carbon isotope ratios (δ13C) and basal area increment (BAI) were used to assess the response of intrinsic water-use efficiency (the ratio of photosynthesis, A to stomatal conductance, g) and growth of individual〉 250-year-old-ponderosa pine trees to stand density reductions. It was hypothesized that reductions in stand density would increase soil moisture availability, thus decreasing canopy A/g and increasing carbon isotope discrimination (Δ). Cellulose-δ13C of annual tree rings, soil water availability (estimated from pre-dawn leaf water potential), photosynthetic capacity, stem basal growth and xylem anatomy were measured in individual trees within three pairs of thinned and un-thinned stands. The thinned stands were treated 7 to 15 years prior to measurement. The values of δ13C and BAI were assessed for 20 consecutive years overlapping the date of thinning in a single intensively studied stand, and was measured for 3 years on either side of the date of thinning for the two other stands to assess the generality of the response.After thinning, Δ increased by 0.89‰ (± 0.15‰). The trees in the un-thinned stands showed no change in Δ (0.00‰ ± 0.04‰). In the intensively studied trees, significant differences were expressed in the first growing season after the thinning took place but it took 6 years before the full 0.89‰ difference was observed. BAI doubled or tripled after disturbance, depending on the stand, and the increased BAI lasted up to 15 years after thinning. In the intensively studied trees, the BAI response did not begin until 3 years after the Δ response, peaked 1 year after the Δ peak, and then BAI and Δ oscillated in unison. The lag between BAI and Δ was not due to slow changes in anatomical properties of the sapwood, because tracheid dimensions and sapwood-specific conductivity remained unchanged after disturbance. The Δ response of thinned trees indicated that A/g decreased after thinning. Photosynthetic capacity, as indexed by foliar nitrogen ([N]) and by the relationship between photosynthesis and internal CO2 (A–Ci curves), was unchanged by thinning, confirming our suspicion that the decline in A/g was due to a relatively greater increase in g in comparison with A. Model estimates agreed with this conclusion, predicting that g increased by nearly 25% after thinning relative to a 15% increase in A. Pre-dawn leaf water potential averaged 0.11 MPa (± 0.03 MPa) less negative for the thinned compared with the un-thinned trees in all stands, and was strongly correlated with Δ post-thinning (R2 = 0.91). There was a strong relationship between BAI and modelled A, suggesting that changes in water availability and g have a significant effect on carbon assimilation and growth of these old trees. These results confirm that stand density reductions result in increased growth of individual trees via increased stomatal conductance. Furthermore, they show that a physiological response to stand density reductions can last for up to 15 years in old ponderosa pines if stand leaf area is not fully re-established.

Notes: Abstract A generalized current efficiency equation was derived from material balance considerations to estimate the caustic current efficiency in ion exchange chlor-alkali membrane cells taking into account the presence of NaHCO3, Na2CO3, and NaOH in the feed brine. The validity and the accuracy of this equation was established by comparing the ‘gas analysis’ results with the data obtained from caustic collection measurements. It is also shown that this general expression can be easily extended to deduce the current efficiency applicable for diaphragm cell operations.

Notes: Summary Microprobeanalyses of 44 vesuvianite specimens of different color, morphology, and occurrence indicate the chemical variation of the species. Vesuvianites can be divided into four types, based on chemistry and color; most vesuvianites can be assigned to one of these types with confidence. Type 1 vesuvianites contain ≈ 2 atoms of Mg, 〈0.25 atoms of Ti, and variable Fe, apparently trivalent, in a formula based on 50 non-H cations. They are dark to pale green, white, or pink. Type 2 vesuvianites contain 〉 2.5 atoms of Mg, variable (divalent?) Fe, and 〈0.5 atoms of Ti. In color they are yellow, yellow-brown, or yellow-green. Type 3 vesuvianites contain divalent Fe, 0.5 to 1.5 atoms of Ti and close to 18 atoms of Si (full occupancy of tetrahedral sites). They are yellow, brown, red-brown, or black. Type 4 vesuvianites are manganoan or cuprian; the studied samples are from Pajsberg, Sweden, Franklin, New Jersey, and Telemark, Norway. In color they are red-brown, purple, blue (“cyprine”), or green. Iron and much of the Mn is apparently trivalent. Unlike garnets, which they resemble structurally, vesuvianites contain almost exclusively Ca in the eight-fold sites in the structure. Silicon occupies 95% or more of the tetrahedral sites. Aluminum fills the smaller octahedral site, A. Chemical variation occurs predominantly in the more open, octahedral, general or G site and in the five-coordinated B site. Simple substitutions in G include Fe3+ or Mn3+ for Al3+, and Fe2+, Mn2+, or Zn2+ for Mg2+. Coupled substitutions include TiO = AIOH, MgTi = AlAl and AlAl = MgSi. The B site may contain Cue2+, Fe2+, Fe3+, or A13+. Changes in the amounts of O and OH in two different positions give a range of anion charge from 146 (0670H12) to about 148 (0690H10).

Notes: Abstract The orientational properties of n-H 2 confined in Vycor have been studied via inelastic neutron spectroscopy. We observe two distinct rotational transitions which we ascribe to H 2 in the center of the pore and H 2 strongly bound to the surface. The molecules on the surface can be modeled as rotationally hindered rotors, and a distribution of orientational potentials is extracted.

Notes: Abstract A total of 40 crude oils from 10 different oil fields in Nigeria were analysed for 39 elements by Instrumental Neutron Activation Analysis (INAA). Significant correlations were found between Ni and V concentrations and Ni versus Se concentrations. The American Petroleum Institute (API) gravities are inversely correlated with total transition metal concentration of the oils but there is no obvious correlation of the V/Ni ratio with the age of the oil fields. The oils are very similar to North Alaska Type B oils in key transition metal parameters and cluster analysis results using the transition metals as variables indicate that the oils might have been formed from two closely related sources.