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  • Polymer and Materials Science  (14)
  • Computational Chemistry and Molecular Modeling  (4)
  • bark beetle  (4)
  • 1
    ISSN: 1573-1561
    Keywords: Dendroctonus brevicomis ; Coleoptera ; Scolytidae ; bark beetle ; western pine beetle ; pheromone ; interruption ; behavior ; release device
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The number of western pine beetles,Dendroctonus brevicomis, trapped at the center of three 90 × 90-m plots was reduced during a 16-hr period after surrounding an attractive source ofexo-brevicomin, frontalin, and myrcene with 16, 48, or 168 sources of the same attractant. Compounds were released from the center of the plot at 1 mg/16 hr/compound, and from the surrounding sources at 4–280 mg/16 hr/compound. About half of these amounts was released between 1530 hr and 1930 hr, the period of peak beetle flight. No treatment differences were apparent in reduction of catch within the range of release rates and spacings tested. When compounds were released continuously from 168 stations for 17 days, catch at the center of a plot was generally lower than catch before or after this period, but fluctuated daily. More beetles were caught on traps hung on ponderosa pines within a plot and the number of these traps catching beetles was greater when compounds were released from all stations than from only the center station. Beetles caught on traps were attracted into the plots from the surrounding forest, but appeared to be dispersed within the plot when compounds were released from many stations.D. brevicomis attacked at least 91 trees in the plots, of which 25 were killed during two summers.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1573-1561
    Keywords: Pinus ponderosa ; Dendroctonus brevicomis ; verbenone ; trans-verbenol ; tree protection ; bark beetle ; pheromones ; interruptant ; Coleoptera ; Scolytidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Verbenone andtrans-verbenol were investigated as candidate interruptants for use as tree protectants. Verbenone andtrans-verbenol, pheromones released byDendroctonus brevicomis during host colonization, reduced the trap catch ofD. brevicomis near sources of the attractant composed ofexo-brevicomm, frontalin, and myrcene. Catch reduction at some trap positions was greater at a high release rate than at a low release rate oftrans-verbenol alone and of the combination of verbenone plustrans-verbenol. Verbenone also reduced catches at traps baited with attractive bolts from trees under attack byD. brevicomis. Attempts to use verbenone to protect living trees fromD. brevicomis attack were inconclusive.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1573-1561
    Keywords: Dendroctonus brevicomis ; Coleptera ; Scolytidae ; bark beetle ; western pine beetle ; attractant rate ; pheromone ; exo-brevicomin ; frontalin ; myrcene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Racemicezo-brevicomin, racemic frontalin, and myrcene were released at two proportions (5∶1∶400 and 1∶1∶1), each at three levels (1 ×, 10 ×, and 100 ×) in a ponderosa pine forest in central California. The 5∶1∶400 mix was based on an estimate of the relative amounts released from a ponderosa pine under attack by the western pine beetle,Dendroctonus brevicomis. MoreD. brevicomis were trapped at a source of the three compounds released at 5∶1∶400 than were trapped at a source released at 1∶1∶1, at all three levels, but this difference was statistically significant only at the 1 × and 10 × levels. Sex ratio of trapped beetles and distribution of catch at the source of attractant and 5 m away apparently did not differ between relative release rates.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 14 (1988), S. 113-122 
    ISSN: 1573-1561
    Keywords: Dendroctonus brevicomis ; Coleoptera ; Scolytidae ; bark beetle ; western pine beetle ; pheromone ; attractant ; inhibitor ; exo-brevicomin ; frontalin ; myrcene ; verbenone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract exo-Brevicomin (E), frontalin (F), and myrcene (M) were released at two rates 10-fold apart with verbenone at four rates 10-fold apart, and without verbenone in plots with one trap on a vertical cylinder at the pheromone source and one trap on each of four cylinders 5 m away. Catch of the western pine beetleDendroctonus brevicomis decreased with increasing levels of verbenone at both release rates of EFM, but not all differences in catch were statistically significant. Significantly more beetles were caught at the high rate of EFM than at the low rate, combining all rates of verbenone. The percent of total beetles caught at the center trap tended to decrease with increasing rates of verbenone, but the only statistically significant differences were at the low rate of EFM.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 61 (1996), S. 9-19 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Results are presented on the preparation and characterization of batch emulsion copolymers of butyl methacrylate and glycidyl methacrylate (GMA). The two main problems occurring during an emulsion copolymerization with GMA are partial hydrolysis of the epoxy groups and internal crosslinking of the latex particles formed. The influence of chain transfer agents (CTA) on the degree of crosslinking was investigated. Furthermore, the effect of reaction temperature and the addition of methacrylic acid on the sol/gel content of the polymer formed and on the rate of epoxy hydrolysis were investigated. It was found that lowering the reaction temperature did not increase the sol content; however, it significantly decreased the extent of hydrolysis. The addition of a CTA (especially CBr4) increased the sol content of the polymer, and good control over the molecular mass was achieved. The addition of methacrylic acid showed that this monomer can be used without any complications with respect to the control of the sol content of the polymer formed. © 1996 John Wiley & Sons, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 31 (1986), S. 965-977 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Liquid crystal polymers (LCP) have been developed for the first time as a thermoplastic matrix for high-performance composites. A successful melt impregnation method has been developed that results in the production of continuous carbon fiber (CF)-reinforced LCP prepreg tape. Subsequent layup and molding of prepreg into laminates has yielded composites of good quality.Tensile and flexural properties of LCP-CF composites are comparable to those of epoxy-CF composites. LCP-CF composites have better impact resistance than the latter, although epoxy-CF composites possess superior compression and shear strength. LCP-CF composites have good property retention until 200°F (67% of room temperature value). Above 200°F, mechanical properties are found to decrease significantly. Experimental results indicate that the poor compression and shear strength may be due to the poor interfacial adhesion between the matrix and carbon fiber.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 25 (1980), S. 2975-2984 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A two-parameter equation is developed that allows for the estimation of the enthalpies of hydrogen formation between two compounds. The compound acting as a proton donor is assigned a donating parameter, and the compound acting as a proton acceptor is assigned an accepting parameter. The compounds described can be assigned both a donating and an accepting parameter. These parameters are derived either from the observed linear relationship between measured hydrogen bond enthalpies and the shift in the OH stretching frequency of alcohols or from the estimated contribution of hydrogen bonding to the cohesive energy density of liquids. The donating parameters correlate well with observed autoprotolysis constants for the several compounds, and the accepting parameters correlate well with observed equilibrium constants for the protonation reaction in which a compound (base) gains a proton. The ability to estimate enthalpies is important in predicting polymeric resin solubilities in solvents.
    Additional Material: 9 Tab.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 32 (1986), S. 5245-5245 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 15 (1989), S. 31-37 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Some results are reported on the alkyllithium-initiated polymerization of butadiene in cyclopentane in presence of 2,′2-bis(4,4,6-trimethyl-1,3-dioxane). The effect of this lithium chelating agent on one-unit model active centres is also reported. Comparisons are made with another highly efficient polymer structure modifier, 1,2-dipiperidinoethane. Conclusions are reached on the reasons why both are particularly effective in inducing the formation of polydienes having extremely high vinyl content.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 0935-9648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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