450 research outputs found

    Evaluation of environmentally friendly products for control of fungal diseases of grapes

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    Various environmentally friendly products were tested for efficacy in controlling powdery mildew, downy mildew, black rot, Phomopsis, and Botrytis bunch rot in grapes over several years. The products tested were: JMS stylet oil (paraffinic oil), Serenade (Bacillus subtilis), Croplife (citrus and coconut extract) + Plant food (foliar fertilizer), Armicarb (potassium bicarbonate), Elexa (chitosan), Milsana (giant knotweed extract), and AQ10 (Ampelomyces quisqua/is). JMS Stylet Oil, Armicarb, Serenade, AQ10, Elexa, and Milsana all provided moderate control of downy and powdery mildew. JMS Stylet Oil and Armicarb also reduced Phomopsis rachis infections. Armicarb looks especially promising for black rot control. Serenade and Croplife + Plantfood provided moderate to good control of Botrytis bunch rot, and moderate control of downy mildew and Phomopsis leaf spot. Milsana provided moderate control of Botrytis bunch rot. The tested products were often out-performed by standard or new products, especially under the humid conditions common in Michigan. However, some products appeared promising for certain diseases and merit further study, especially those that may be of interest to organic growers. Optimizing timing of these products may enhance their performance, since most of them are protectants and have little or no eradicant activity

    Effects of electroplating on the mechanical properties of stereolithography and laser sintered parts

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    This paper provides a quantitative and qualitative assessment of the effects of electroplating on polymer parts made by stereolithography and laser sintering. A series of test samples were coated with copper and nickel with varying thickness. Thicker coatings (120μm) were reproduced with a repeatability that should not adversely affect the tolerances with which such parts may be produced given the tolerances of the initial rapid prototyping processes themselves. Thinner coatings (20μm) resulted in a smother surface finish than thicker coatings for stereolithography parts, however the converse was true for laser-sintered parts. Composite theory was used to predict that thicker coating would lead to higher Young’s modulus in parts and this was shown to be true in physical tests although the practical values were lower than the predicted values especially for thicker coatings. Physical tests also confirmed that thicker coatings increased UTS and impact energy but had a minimal effect on the ductility of parts

    Search for Exotic Mesons in pi- P Interactions at 18 GeV/c

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    The recent search for non qqˉq \bar{q} mesons in πp\pi^{-}p interactions at Brookhaven National Laboratory is summarized. Many final states such as ηπ\eta \pi, ηπ\eta' \pi^{-}, a0πa_{0} \pi, f1πf_{1} \pi, a2πa_{2} \pi, b1πb_{1} \pi, which are favored decay modes of exotics, are under investigation.Comment: 9 pages, PostScript, Presented at the International School of Nuclear Physics, Erice, Sicily, Italy, September 199

    Tau and Charm physics highlights

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    In tau physics, we are at the frontier between the completion of the LEP program and the start of analyses from b-factories, which are expected to produce results in the coming years. Nice results from CLEO are steadily delivered in the meantime. For charm, impressive progress have been achieved by fixed target experiments in the search for CP violation and D^0 - \bar D^0 oscillations. First results from b-factories demonstrate the power of these facilities in such areas. The novel measurement of the D* width by CLEO happens to be rather different from current expectations. The absence of a charm factory explains the lack or the very slow progress in the absolute scale determinations for charm decays.Comment: "Typos corrected and references added

    Rare charm meson decays D->Pl^+l^- and c->ul^+l^- in SM and MSSM

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    We study the nine possible rare charm meson decays D->Pl^+l^- (P=pi,K,eta,eta') using the Heavy Meson Chiral Lagrangians and find them to be dominated by the long distance contributions. The decay D^+ -> pi^+l^+l^- with the branching ratio 1*10^(-6) is expected to have the best chances for an early experimental discovery. The short distance contribution in the five Cabibbo suppressed channels arises via the c->ul^+l^- transition; we find that this contribution is detectable only in the D->pi l^+l^- decay, where it dominates the differential spectrum at high-q^2. The general Minimal Supersymmetric Standard Model can enhance the c->ul^+l^- rate by up to an order of magnitude; its effect on the D->Pl^+l^- rates is small since the c->ul^+l^- enhancement is sizable in low-q^2 region, which is inhibited in the hadronic decay.Comment: 17 page

    A Heavy-Light Chiral Quark Model

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    We present a new chiral quark model for mesons involving a heavy and a light (anti-) quark. The model relates various combinations of a quark - meson coupling constant and loop integrals to physical quantities. Then, some quantities may be predicted and some used as input. The extension from other similar models is that the present model includes the lowest order gluon condensate of the order (300 MeV)^4 determined by the mass splitting of the 0^- and the 1^- heavy meson states. Within the model, we find a reasonable description of parameters such as the decay constants f_B and f_D, the Isgur-Wise function and the axial vector coupling g_A in chiral perturbation theory for light and heavy mesons.Comment: 31 pages, 13 figures, RevTex4.

    Observation of a New J(PC)=1(+-) Isoscalar State in the Reaction Pi- Proton -> Omega Eta Neutron at 18 GeV/c

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    Results are presented on a partial wave analysis of the Omega Eta final state produced in Pi- Proton interactions at 18 GeVc where Omega -> Pi+ Pi- Pi0, Pi0 -> 2 Gammas, and Eta -> 2 Gammas. We observe the previously unreported decay mode Omega(1650) -> Omega Eta and a new 1(+-) meson state h1(1595) with a mass M=1594(15)(+10)(-60) MeV/c^2 and a width Gamma=384(60)(+70)(-100) MeV/c^2. The h1(1595) state exhibits resonant-like phase motion relative to the Omega(1650).Comment: Submitted to Physics Letters B Eight total pages including 11 figures and 1 tabl

    Kinetic Monte Carlo Simulation of Strained Heteroepitaxial Growth with Intermixing

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    An efficient method for the simulation of strained heteroepitaxial growth with intermixing using kinetic Monte Carlo is presented. The model used is based on a solid-on-solid bond counting formulation in which elastic effects are incorporated using a ball and spring model. While idealized, this model nevertheless captures many aspects of heteroepitaxial growth, including nucleation, surface diffusion, and long range effects due elastic interaction. The algorithm combines a fast evaluation of the elastic displacement field with an efficient implementation of a rejection-reduced kinetic Monte Carlo based on using upper bounds for the rates. The former is achieved by using a multigrid method for global updates of the displacement field and an expanding box method for local updates. The simulations show the importance of intermixing on the growth of a strained film. Further the method is used to simulate the growth of self-assembled stacked quantum dots
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