Theoretical Study Of The Gas-phase Reaction: Sf6 + Co + → Sf5 + + Fco

Theoretical calculations using effective core potential (ECP) based methods were performed for a large number of molecular systems related to SF 6. Hartree-Fock (HF), MP2 and QCISD(T) methods were used. The quantities computed include equilibrium molecular geometries, bond dissociation energies, and adiabatic ionization energies. Where possible these quantities are compared with information available in the literature. The equilibrium geometries produced using the ECP-based methods are in very good agreement with structures reported in the literature. For the various energy differences, corresponding to the processes listed above, the ECP-based energies reproduce the trends. In addition to calculations on individual molecules, the reaction of SF6 with CO+ was studied. The first objective was to locate the reactant ion-molecule complex, the transition state, and the product ion-molecule complex for each of these systems. In this reaction neither a transition state nor a reactant ion-molecule complex could be located using HF-based forces and energies, reaction seemed to pass without a barrier to SF5 + + FCO. The use of a CASSCF(7,7)/B0 method was required to find the reactant ion-molecule complex. Finally more detailed studies were made of how the energy and charge distribution change as the reaction proceeds from reactants to products. It was observed that the reaction SF6 + CO+ → SF5 + + FCO occurs via F- abstraction, with the electronic energy barrier of 103.86 kJ mol-1. ©2008 Sociedade Brasileira de Química.1917480Kennedy, R.A., Mayhew, C.A., Thomas, R., Watts, P., (2003) Inter. J. Mass Spectrom, 223, p. 627Chim, R.Y.L., Kennedy, R.A., Tuckett, R.P., (2003) Chem. Phys. Lett, 367, p. 697Anglada, J.M., (2004) J. Am. Chem. Soc, 126, p. 9809Penteado, J.C.P., Seoud, O.A.E., Carvalho, L.R.F., (2006) Quim. Nova, 29, p. 1038SF6 Emission Reduction Partnership for Electric Power Systems, , http://www.epa.gov/highgwp/electricpower-sf6, Accessed on August 9, 2006Atterbury, C., Kennedy, R.A., Mayhew, C.A., Tuckett, R.P., (2001) Phys. Chem. Chem. Phys, 3, p. 1949Giroldo, T., Xavier, L.A., Riveros, J.M., (2004) Angew. Chem., Int. Ed, 43, p. 3588Jarvis, G.K., Kennedy, R.A., Mayhew, C.A., Tuckett, R.P., (2000) J. Phys. Chem. A, 104, p. 10766Jarvis, G.K., Kennedy, R.A., Mayhew, C.A., (2001) Int. J. Mass Spectrom, 205, p. 257Kennedy, R.A., Mayhew, C.A., (2001) Int. J. Mass Spectrom, 206, pp. AR1Chim, R.Y.L., Kennedy, R.A., Zhou, R.P.T.W.D., Collins, D.J., Hatherly, P.A., (2001) J. Phys. Chem. A, 105, p. 8403Kennedy, R.A., Mayhew, C.A., (2001) Phys. Chem. Chem. Phys, 3, p. 5511Atterbury, C., Critchley, A.D.J., Kennedy, R.A., Mayhew, C.A., Tuckett, R.P., (2002) Phys. Chem. Chem. Phys, 4, p. 2206Basta, R.B. G. Harvey, A. M. A.Ernst, R. D.J. Am. Chem. Soc. 2005, 127, 11924Custodio, R., Giordan, M., Morgon, N.H., Goddard, J.D., (1992) Int. J. Quantum Chem, 42, p. 411Custodio, R., Goddard, J.D., Giordan, M., Morgon, N.H., (1992) Can. J. Chem, 70, p. 580Morgon, N.H., (1998) J. Phys. Chem, 102, p. 2050Morgon, N.H., Argenton, A.B., Silva, M.L.P., Riveros, J.M., (1997) J. Am. Chem. Soc, 119, p. 1708Morgon, N.H., Riveros, J.M., (1998) J. Phys. Chem. A, 102, p. 10399Morgon, N.H., (2006) Int. J. Quantum Chem, 106, p. 2658Stevens, W.J., Basch, H., Kraus, M., (1984) J. Chem. Phys, 81, p. 6026Morgon, N.H., Custodio, R., Riveros, J.M., (1995) Chem. Phys. Lett, 235, p. 436Gaussian 98 Revision A.7, Frisch, M. J, Trucks, G. W, Schlegel, H. B, Scuseria, G. E, Robb, M. A, Cheeseman, J. R, Zakrzewski, V. G, Jr, J. A. M, Stratmann, R. E, Burant, J. C, Dapprich, S, Millam, J. M, Daniels, A. D, Kudin, K. N, Strain, M. C, Farkas, O, Tomasi, J, Barone, V, Cossi, M, Cammi, R, Mennucci, B, Pomelli, C, Adamo, C, Clifford, S, Ochterski, J, Petersson, G. A, Ayala, P. Y, Cui, Q, Morokuma, K, Malick, D. K, Rabuck, A. D, Raghavachari, K, Foresman, J. B, Cioslowski, J, Ortiz, J. V, Baboul, A. G, Stefanov, B. B, Liu, G, Liashenko, A, Piskorz, P, Komaromi, I, Gomperts, R, Martin, R. L, Fox, D. J, Keith, T, Al-Laham, M. A, Peng, C. Y, Nanayakkara, A, Gonzalez, C, Challacombe, M, Gill, P. M. W, Johnson, B. G, Chen, W, Wong, M. W, Andres, J. L, Head-Gordon, M, Replogle, E. S, Pople, J. A, Gaussian Inc, Pittsburgh PA, 1998Irikura, K.K., (1995) J. Chem. Phys, 102, p. 5357Bauschlicher Jr., C.W., Ricca, A., (1998) J. Phys. Chem. A, 102, p. 4722Gonzales, C., Schlegel, H.B., (1989) J. Chem. Phys, 90, p. 2154Eyring, H., (1935) J. Chem. Phys, 3, p. 107Truhlar, D.G., Hase, W.L., Hynes, J.T., (1983) J. Phys. Chem, 87, p. 2264Tsang, W., Herron, J.T., (1992) J. Chem. Phys, 96, p. 427

Effect of early sowing on the growth, yield and quality of sugar beet.

End of Project ReportExperiments have shown that yield of sugar is closely related to the amount of solar radiation intercepted by a sugar beet crop. Early sowing increases leaf area from May onwards when radiation is at its maximum and provides a basis for increasing yields. In the past, bolting has been an undesirable consequence of early sowing but some modern cultivars have good bolting resistance and can be sown early with a limited risk of bolting. This study, conducted from 1994 to 1998, compared the performance of two cultivars, Celt and Monofeb, at three sowing dates and three harvest dates. In replicated experiments, plant establishment, crop development, and root yield and quality were assessed. The effect of sowing date on solar radiation interception was studied. Effects of in-furrow pesticide application on pest numbers and plant damage were also measured. Plant establishment was influenced by sowing date with the early sowings generally giving lower plant numbers than the later ones. The cultivar Celt produced higher populations than Monofeb at all sowing dates. Early sowing increased the leaf area index (a measure of the ratio of leaf to land area) and consequently the amount of solar radiation intercepted. This was particularly so in June when solar radiation levels are highest. Early crop establishment provides the opportunity to exploit good weather conditions which may occur in April or May. Pest numbers generally were small at all the sites. Insecticide had a greater effect on pest numbers and plant damage than it had on plant establishment; the beneficial effects of pesticide were slightly more pronounced for the early and mid-season sowings than for later-sown beet. Seedling diseases were not a problem at any time of sowing. Poor emergence, where it occurred, was not associated with pre-emergence disease. Early to mid-March sowings produced significantly higher yields of roots and sugar than the early or late April sowings over the period of the experiment. Even in years when plant populations from the first sowings were much lower than subsequent sowings, yields tended to be at least equal to those of later sowings. Monofeb produced a slightly higher root yield than Celt, but because it had lower sugar contents there was no difference in sugar yields. Harvesting extended over the period from early October to mid-November and root growth and sugar production increased over that period irrespective of sowing date. Bolting was a problem in 1996 on the early-sown plots, particularly with the cultivar Celt.Teagasc acknowledges the support of Irish Sugar plc and Sugar Beet Levy Farmer Funds in the financing of this projec

Buried treasure—marine turtles do not ‘disguise’ or ‘camouflage’ their nests but avoid them and create a decoy trail

After laying their eggs and refilling the egg chamber, sea turtles scatter sand extensively around the nest site. This is presumed to camouflage the nest, or optimize local conditions for egg development, but a consensus on its function is lacking. We quantified activity and mapped the movements of hawksbill (Eretmochelys imbricata) and leatherback (Dermochelys coriacea) turtles during sand-scattering. For leatherbacks, we also recorded activity at each sand-scattering position. For hawksbills, we recorded breathing rates during nesting as an indicator of metabolic investment and compared with published values for leatherbacks. Temporal and inferred metabolic investment in sand-scattering was substantial for both species. Neither species remained near the nest while sand-scattering, instead moving to several other positions to scatter sand, changing direction each time, progressively displacing themselves from the nest site. Movement patterns were highly diverse between individuals, but activity at each sand-scattering position changed little between completion of egg chamber refilling and return to the sea. Our findings are inconsistent with sand-scattering being to directly camouflage the nest, or primarily for modifying the nest-proximal environment. Instead, they are consistent with the construction of a series of dispersed decoy nests that may reduce the discovery of nests by predators

A study of cultivation and sowing systems for cereals.

End of Project ReportDue to the pressure on cereal margins growers are seeking ways of reducing their costs of production. Reduced cultivation may provide cheaper and faster crop establishment, but in the past has been subject to problems with (poor crop establishment) weeds and soil compaction. With modern cultivation and sowing technology and methodology it may be possible to overcome these difficulties. In addition reduced cultivation is considered to be more environmentally friendly and sustainable than the conventional plough-based system. With these considerations in mind it was decided to start an experiment in autumn 2000 to compare the conventional system (PL) with reduced cultivation (RC) for crop establishment, and to examine the effect of incorporating the straw into then soil or baling and removing it. The treatments were assessed on winter wheat, and winter and spring barley. The parameters assessed included – crop establishment, yield and quality effects on disease levels, invertebrate pests and beneficials (aphids, slugs, earthworms, beetles), and soil conditions. The work reported here was conducted on four trial sites at Oak Park, Carlow and Knockbeg, Co. Laois from 2000 to 2003. the objectives were to establish the efficacy of RC compared with PL and to its effects on the parameters outlined above. Plant establishment was lower after RC in most of the experiments. Winter wheat yields were good irrespective of the number of plants established and there were no significant differences between cultivation or straw disposal method. The relative yields of the PL and RC treatments in winter barley varied over the three years; in 2001 there was no difference, in 2002 PL yielded 1 t/ha more than RC, while in 2003 the PL area produced 2 t/ha extra. Spring barley yields were similar on the PL and RC treatments. Broadleaved weeds were not a problem on the PL or RC treatments but there were more annual grass weeds on the RC plots. This was particularly serious in the winter barley experiments where sterile brome (Bromus sterilis) had a big effect on yield by 2003. annual meadow grass (Poa annua) was a problem in both PL and RC areas if not controlled by timely herbicide application; this was particularly so on the headland areas in the spring barley field. Disease assessment on the winter wheat trail showed no significant differences in Take-all or Eyespot levels between cultivation or straw disposal methods, although Take-all levels tended to be lower on the RC plots. Soil strength as measured by cone penetrometer and shear vane was higher on the RC treatments. In the winter wheat there was no difference in slug numbers between any of the treatments. Leaf damage by slugs increased in RC relative to PL but not significantly, in 2003. No below ground slug damage was found. Earthworm numbers in the winter barley increased significantly on the RC treatment relative to the PL as the study progressed. Straw incorporation increased earthworm numbers on both PL and RC treatments. Allolobophora chlorotia was the most common species in 2004. In the winter wheat the RC and straw incorporation increased earthworm numbers. Cultivation method had a greater effect on ground beetle numbers than method of straw disposal. Large species (e.g. Pterostichies malanarius) were favoured by RC while smaller species (e.g. Bembidon species) were more numerous in the PL plots. Molecular studies on virus diseases, vectors and vector-predators are underway in progress. In the invertebrate pests and beneficials investigations the RC winter barley had 11% fewer aphids and 27% less BYDV than the PL. Incorporating straw reduced aphid numbers and virus incidence by 36% and 32% respectively; the comparable values for the PL + straw treatment were 15% and 15%. In the winter wheat there was less BYDV in the RC plots than the PL + less were the straw was incorporated than where the straw was removed. Aphid infestation of wheat ears was low in the three years of the experiment. The insecticide seed treatment imidacloprid significantly reduced aphid numbers and virus incidence in winter barley but was less effective than a single insecticide spray in controlling the disease. The seed treatment was more effective in controlling BYDV in RC than in the PL plots. Estimations of slug numbers in the winter barley showed that the dominant species was the grey field slug (Deroceras reticulatum). Slug numbers increased significantly on all treatments between 2001 and 2004. In November 2004, slugs were significantly more numerous in the RC treatments than in the PL areas. Leaf damage was proportional to slug populations, but the slugs did not damage the barely seed or reduce plant populations in continuous winter barley under RC. Root and stem diseases (Take-all and Eyespot) were not nay worse under RC than after PL. In fact there was a tendency towards lower disease levels on the RC areas and there was significantly less sharp eyespot on the RC treatment

The spectral gap for some spin chains with discrete symmetry breaking

We prove that for any finite set of generalized valence bond solid (GVBS) states of a quantum spin chain there exists a translation invariant finite-range Hamiltonian for which this set is the set of ground states. This result implies that there are GVBS models with arbitrary broken discrete symmetries that are described as combinations of lattice translations, lattice reflections, and local unitary or anti-unitary transformations. We also show that all GVBS models that satisfy some natural conditions have a spectral gap. The existence of a spectral gap is obtained by applying a simple and quite general strategy for proving lower bounds on the spectral gap of the generator of a classical or quantum spin dynamics. This general scheme is interesting in its own right and therefore, although the basic idea is not new, we present it in a system-independent setting. The results are illustrated with an number of examples.Comment: 48 pages, Plain TeX, BN26/Oct/9

Creating diamond color centers for quantum optical applications

Nitrogen vacancy (NV) centers in diamond have distinct promise as solid-state qubits. This is because of their large dipole moment, convenient level structure and very long room-temperature coherence times. In general, a combination of ion irradiation and subsequent annealing is used to create the centers, however for the rigorous demands of quantum computing all processes need to be optimized, and decoherence due to the residual damage caused by the implantation process itself must be mitigated. To that end we have studied photoluminescence (PL) from NV$^-$, NV$^0$ and GR1 centers formed by ion implantation of 2MeV He ions over a wide range of fluences. The sample was annealed at $600^{\circ}$C to minimize residual vacancy diffusion, allowing for the concurrent analysis of PL from NV centers and irradiation induced vacancies (GR1). We find non-monotic PL intensities with increasing ion fluence, monotonic increasing PL in NV$^0$/NV$^-$ and GR1/(NV$^0$ + NV$^1$) ratios, and increasing inhomogeneous broadening of the zero-phonon lines with increasing ion fluence. All these results shed important light on the optimal formation conditions for NV qubits. We apply our findings to an off-resonant photonic quantum memory scheme using vibronic sidebands

Wireless power and network synchronisation for agricultural and industrial remote sensors using low voltage CMOS Harvesting and Data Demodulator IC

This paper presents a wide area medium frequency loosely coupled magnetic energy harvesting system with power delivery and network synchronisation for remote sensors, intended for agricultural and industrial environments. Intended for situations with poor service access, power is supplied from a source via a large area loop. Receiver nodes may use ferrite cored coils for good efficiency with modest volume. Transmission of low bandwidth network synchronisation data permits very low operational duty cycle with the need for real time clocks or wake up receivers and their associated power drain. As a key enabler for the system, a full custom energy harvester and QPSK data demodulator IC has been designed and fabricated in a commercial 180nm CMOS technology. The IC occupies 0.54mm2 and can deliver 10.3µW at 3V to an external battery or capacitor. With standard MOS device thresholds the rectifier can start from cold with only 250mV peak from the antenna loop, and the battery charge output is delivered with 330mV peak input. Results are presented from laboratory evaluation and from preliminary measurements in the field with a 10m x 10m loop driven at 800kHz

Reperfusion in acute myocardial infarction

Studies of the pathophysiology of acute myocardial infarction (AMI) have shown that in most pa- tients a thrombus forms over a ruptured ather- oma in the infarct-related coronary artery and obstructs the artery

An expert assessment on playspace designs and thermal environments in a Canadian context

Playgrounds are a hub for child play and concerns that may impact children\u27s play there may hinder their health and well-being. Extreme temperatures can increase risks in children of sunstroke, burns from playground surfaces, and exposure to ultraviolet radiation. Despite health risks from extreme heat to children, existing playground design standards around the world, including in Canada, make little-to-no mention of how to design playgrounds for thermal comfort, particularly in summer. To help fill this gap in the Canadian context, several organizations collaborated to develop guidance for thermally comfortable playgrounds in Canada. As part of this project, an online survey was administered to 55 experts with diverse professional backgrounds, largely from Canada and the United States, to determine how thermal comfort is viewed in playground design and safety. Survey results showed agreement among experts that thermal comfort receives low or no priority in playground design but should be prioritized or considered alongside other safety factors in relevant playground safety guidelines and standards. The results of this survey not only helped inform the 2020 publication of a Thermal Comfort annex to the CSA Group\u27s Children\u27s playgrounds and equipment standard (CAN/CSA Z614) but could also help inform future research and practice globally