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Theoretical Studies Of The Reactions Xhn → Xhn-1- + H+ And Xhn-1- + Sih4 → [Sih4xhn-1]-, Mark S. Gordon, Larry P. Davis, Larry W. Burggraf, Robert Damrauer

Mark S. Gordon

Ab initio and MNDO calculations have been carried out to evaluate the gas-phase acidities of closed-shell XHn compounds (X= C, N, 0, F, Si, P, S, Cl) and the affinities of silane for the XHn_1- anions. Fourth-order perturbation theory with extended basis sets reproduces the experimental gas-phase acidities to within 2 kcaljmol. Stable pentacoordinated silicon anions are found for X = H, C, N, 0, and F. In contrast, only marginally stable charge-dipole complexes are found for X = Si, S, and Cl.

On The Glass Transition And Viscosity Of Phosphorus Pentoxide, C. A. Angell, Steve W. Martin

Steve W. Martin

The calorimetric glass transition temperature Tg for pure anhydrous P2Os melted in sealed Si02 ampules at 1000 “C has been obtained directly for the first time with differential scanning calorimetry, and the increase in heat capacity at Tg has been determined. Tg measured in this way is 57 K higher than the value quoted in the literature, which is probably based on an Arrhenius law extrapolation of viscosity data to 9 = lOI3 P. Combining the high-temperature viscosity data with the common observation that, for oxide glasses, 7 = 10l2 P at the DSC Tg, we find that the P,O, …

Thermodynamic Character Of The Vibron Frequencies And Equation Of State In Dense, High-Temperature, Fluid N 2, R. D. Etters, J. Belak, Richard Alan Lesar

Richard Alan Lesar

The pressure-temperature dependence of the vibron stretching mode frequency, the intramolecular bond lengths, and the pressure-volume curves along various isotherms are calculated for fluid N 2 in the ranges 2≤P≤150 kbar and 300≤T≤1500 K. A constant-pressure Monte Carlo procedure with continuously deformable, periodic boundary conditions is used. The results are in good agreement with recent high-temperature diamond cell, dynamic shock, and earlier P-V data.

Laying-Worker Production Of Drones In Mixed Colonies Of Africanized And European Honey Bees (Hymenoptera: Apidae), Richard L. Hellmich Ii, Robert G. Danka, Anita M. Collins, Thomas E. Rinderer

Richard L Hellmich

Queenless honey-bee colonies (Apis mellifera L.) with mixed populations of Africanized and European workers produced 15-fold more Africanized drones than European drones. Drones developed from eggs laid by previously nonreproductive workers. First eclosion of Africanized drones preceded that of European drones by 2.4 days. Laying workers of both bee types developed more rapidly when colonies had Africanized queens and brood before queenlessness than when colonies had European queens and brood. The percentage of European drones of the total number of drones that eclosed each day changed significantly in a curvilinear manner over 15 days, starting near 0, increasing to a …

Scaling All Correlation Energy In Perturbation Theory Calculations Of Bond Energies And Barrier Heights, Mark S. Gordon, Donald G. Truhlar

Mark S. Gordon

We present and test a new method for scaling all correlation energy as estimated by M0ller-Plesset many-body perturbation theory with popular basis sets. Scale factors that may be useful for future applications are estimated from known bond dissociation energies. We also use scale factors to estimate the barrier heights for two hydrogen-transfer reactions, CH3 + H2 = CH4 + H and OH + CH4 = H20 + CH3•

Ferromagnetism Versus Antiferromagnetism In Face-Centered-Cubic Iron, F. J. Pinski, J. Staunton, B. L. Gyorffy, Duane D. Johnson, G. M. Stocks

Duane D. Johnson

Using a first-principles disordered-local-moment picture of itinerant-electron magnetism, we calculated the temperature and volume dependence of the magnetic moment and spin-spin correlations for fcc Fe in the paramagnetic state.

Density-Functional Theory For Random Alloys: Total Energy Within The Coherent-Potential Approximation, Duane D. Johnson, D. M. Nicholson, F. J. Pinski, B. L. Gyorffy, G. M. Stocks

Duane D. Johnson

A density-functional-based theory is developed for calculation of the total energy and pressure of random substitutional alloys within the Korringa-Kohn-Rostoker coherent-potential approximation. The theory is used to calculate the concentration variation of the equilibrium lattice spacing of α-phase CucZn1−c alloys. We find, in agreement with experiment, that the variation is almost linear and that it deviates from Vegard's rule.

Potential Primary Pyrolysis Processes For Disilane, Mark S. Gordon, Thanh N. Truong, Elizabeth K. Bonderson

Mark S. Gordon

Four competing unimolecular decomposition pathways for disilane are considered with use of MP4 energies obtained with an extended basis set and geometries obtained at the MP2/6-31G** computational level. The 1,1- and 1,2-eliminations of H2 and the elimination of silylene to form silane all have similar endothermicities, but the very high activation energy for the I ,2-elimination eliminates this process as a significant contributor at low energies. If disilene is formed in the thermal decomposition of disilane, the more likely source is its higher energy isomer silylsilylene via a relatively low energy I ,2-hydrogen shift.

Thermal Decomposition Of Silane, Mark S. Gordon, David R. Gano, J. Stephen Binkley, Michael J. Frisch

Mark S. Gordon

The essential features of the potential energy surface for the thermal decomposition of silane have been calculated with extended basis sets, augmented by correlation corrections. It is predicted that the transition state for the molecular elimination lies 56.9 kcaljmol above silane. For the reverse reaction, the transition state is less than 2 kcal/mol above the separated fragments, silylene and molecular hydrogen, but 4.8 kcal/mol above a long-range potential well. In the latter, the silylene-H2 separation is 1.78 A, and the bond in H2 has stretched by more than 0.05 A. This indicates a significant electronic interaction between the fragments even …

Theoretical Studies Of Reactions Of Silanimine (H2sinh) And Its Isomer Aminosilylene (Hsinh2), Thanh N. Truong, Mark S. Gordon

Mark S. Gordon

The structure and reactivity of unsaturated singlet silicon-nitrogen compounds is theoretically investigated. Ab initio calculations demonstrate that the planar silylene HSiNH2 is the global minimum on the SiNH3 surface, with the planar doubly bound species H2SiNH 18 kcaljmol higher in energy. The internal rotational barriers are computed to be 26.9 kcaljmol for HSiNH2 and 37.9 kcaljmol for H2SiNH. However, the barrier for the inversion of H2SiNH is only 5.6 kcaljmol, so that inversion is favored over rotation for this species. The isomerization connecting H2SiNH to HSiNH2 has a barrier of 60 kcaljmol. The transition-state structures, as well as the exothermicities …

Corbicular Size In Workers From Honeybee Lines Selected For High Or Low Pollen Hoarding, Charles P. Milne Jr., Richard L. Hellmich Ii, Karen J. Pries

Richard L Hellmich

Measurements were made of corbicular areas (of a total of 1025 corbiculae) in 2 lines of honeybees (Apis mellifera) selected for high and low pollen hoarding respectively. The sample from each line comprised about 30 newly emerged workers from each of 9 queens representing 3 sublines. Analyses of variance revealed highly significant differences among the 18 queens (P « 0.0001) and between the lines (P « 0.0001). Mean corbicular area for the high pollen-hoarding line (1.909 ± 0.004 mm2) was greater than for the low hoarding line (1.874 ± 0.003 mm2), Of the 9 queens whose worker progeny had the …

Soymilk Process., Lawrence A. Johnson, Charles W. Deyoe, William J. Hoover

Lawrence A. Johnson

Process for making a soybeanbased milk analog or soymilk and food products prepared therefrom. The process involves the comminuting of whole soybeans having the hulls thereon; forming a slurry of the comminuted soybeans; simultaneously initiating the inactivation of trypsin inhibitor and lipoxygenase without fixing protein bodies or substantially denaturing the soybean protein; confining the heated slurry until the trypsin inhibitor activity is reduced to a desired value; cooling the slurry; and separating the hulls from the slurry to recover the desired product. The resulting soymilk is an aqueous preparation of the soybean which exhibits minimal destruction of essential amino acids, …

Comparative Toxicities Of Four Topically Applied Insecticides To Africanized And European Honey Bees (Hymenoptera: Apidae), Robert G. Danka, Thomas E. Rinderer, Richard L. Hellmich, Anita M. Collins

Richard L Hellmich

Contact toxicities were established for acetone formulations of azinphosmethyl, carbaryl, methyl parathion, and permethrin applied to workers of Africanized and European honey bee (Apis mellifera L.) types. For each insecticide, 95% fiducial limits at the LC50 levels for the two bee types did not overlap. Africanized bees showed greater tolerance to all the chemicals except carbaryl; differences in tolerance to each of the four chemicals were all about 2-fold. The order of toxicity of the compounds on the Africanized bees was permethrin > carbaryl > azinphosmethyl > methyl parathion; on the European honey bees, the order of toxicity was permethrin > azinphosmethyl > carbaryl> methyl …

Pollen Hoarding And Use By High And Low Pollen-Hoarding Honeybees During The Course Of Brood Rearing, Richard L. Hellmich Ii, Walter C. Rothenbuhler

Richard L Hellmich

Honeybees (Apis mellifera) from a line which had been selected for high pollen-hoarding behaviour (HPH) hoarded more pollen than bees from a low pollen-hoarding line (LPH) when they were kept in observation colonies with known amounts of brood. These differences were not found when brood was in the egg stage and pollen stores were small, but were large and significant when brood was in the larval stage and pollen stores was more abundant. Differences in amounts of stored pollen that were established between the lines during the larval stage were maintained after brood cells were capped, but amounts of pollen …

Additional Mapping Of Isozyme Loci: Localization Of Acp4, Dia2, Adkl, Tpi3, And Sadl, Jonathan F. Wendel, Major M. Goodman, Charles W. Stuber

Jonathan F. Wendel

We recently listed the isozyme loci being studied by starch gel electrophoresis in our laboratory and summarized the available mapping data in a series of reports (Wendel et al., MGCNL 59:87-90). Subsequent work has resulted in further clarification of the chromosomal locations of markers on chromosomes 1 (Acp4, Dia2), 6 (Adkl), 8 (Tpi3), and 10 (Sadl). Previously unreported information on these loci and their chromosomal locations follows.

Sem Views Of Oak Wood, Douglas D. Stokke

Douglas D. Stokke

The anatomical structure of the secondary xylem (wood) of trees varies with location in the tree. The size, shape, and distribution of cell types varies not only between locations (i.e., stem vs. branch vs. root), but also within an annual ring or across annual rings at a given cross-sectional plane.

Foraging Population Sizes Of Africanized And European Honey Bee (Apis Mellifera L.) Colonies, Thomas E. Rinderer, Robert G. Danka, Richard L. Hellmich Ii, Anita M. Collins

Richard L Hellmich

Foraging population sizes in Africanized (A) and European (E) honey-bee (Apis mellifera L.) colonies were determined by trapping returning foragers at the hive. E colonies fielded

significantly larger foraging populations than A colonies. E colonies showed much larger variability in sizes of foraging populations than A colonies, responding with more foragers as colony size was increased and especially when nectar was more abundant.

The percentage of colony members foraging was similar for both sizes (1 and 3 kg of adult bees) of E colonies ; 1 kg A colonies had a greater percentage of foragers than 3 kg A colonies.E …

Tpi4 Is Located Near The Centromere On The Long Arm Of Chromosome 3, Jonathan F. Wendel, J. B. Beckett

Jonathan F. Wendel

Tpi4, one of the three genes encoding cytosolic triose phosphate isomerase isozymes, was earlier shown to be on 3L between Pgd2 (phosphogluconate dehydrogenase) and the centromere (Wendel et al., MNL 59:88). In an effort to better localize Tpi4, a series of crosses was made between Tpi4 testers and stocks carrying three B-A translocations believed to be near the centromere on 3L.

Comparison Of Africanized And European Queen-Mating Colonies In Venezuela, Richard L. Hellmich Ii, Robert G. Danka, Thomas E. Rinderer, Anita M. Collins

Richard L Hellmich

Africanized queen-mating colonies produced fewer mated queens (P < 0.05), absconded more (P < 0.001) and had more population dwindling (P < 0.03) when compared to European queenmating colonies. Africanized colonies most affected by these factors were 5-1 nuclei, the type of mating nuclei most commonly used by U.S. queen producers. Efficiency of queen production was increased by doubling bee populations and hive volume and by adding brood.

Regulation Of The Hoarding Efficiency Of Africanized And European Honey Bees, Anita M. Collins, Thomas E. Rinderer, Richard L. Hellmich, Robert G. Danka

Richard L Hellmich

In laboratory cages, European bees hoarded more sucrose solution, and did so with greater efficiency than Africanized bees. Additional empty comb caused both Africanized and European bees to increase both their hoarding intensities and efficiencies. The proportional increase in hoarding intensity was somewhat less for the Africanized bees but the proportional increase in efficiency was similar for Africanized and European bees.

Relationship Between Different Amounts Of Brood And The Collection And Use Of Pollen By The Honey Bee (Apis Mellifera), Richard L. Hellmich Ii, Walter C. Rothenbuhler

Richard L Hellmich

Observation colonies each with approximately 1000 bees were given three levels of brood (0, 100 and 400 cells). Foraging was restricted to artificial sources in flight cages. Collection, storage and use of pollen increased with brood level. Eggs and larvae stimulated pollen foraging, and larvae, particularly older larvae, stimulated pollen use.

Π-Bond Strengths In Hp=Ph, H2p=P, Hp=Nh, And Hn=Nh, Michael W. Schmidt, Mark S. Gordon

Mark S. Gordon

The chemistry of the HP=PH 1r bond found in the recently isolated diphosphene compounds is considered in several ways. The P=P 1r-bond strength is found by computing the rotation barrier (36 kcalfmol) and is compared to that found for HN=NH (63.5 kcalfmol) and HP=NH (47 kcalfmol). The structure of the HPPH anion is presented. Various electronic states of the H2PP isomer are considered and compared to those of HPPH. Dipole moments and PP stretching frequencies are reported. The concerted hydrogenation of diphosphene is also examined.

An Electron–Gas Plus Damped‐Dispersion Calculation Of The N2–N2 Interaction, Richard Alan Lesar, M. S. Shaw

Richard Alan Lesar

We present the results of a calculation of the N2–N2intermolecular potential using the modified Gordon–Kim (electron–gas) model with damped‐dispersion terms (MGKD potential). The calculated potential agrees well in the well region with other proposed potentials. An analytical form that fits the potential with an average error of 0.2% from the well region to 30 kK on the repulsive wall is given. Solid‐state properties, such as the 0 K phase diagram and the pressure–volume curve, are calculated and are in good agreement with experiment. As a test of the repulsive region, the shock Hugoniot calculated with this potential is compared with …