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Damage Threshold (damage + threshold)
Selected AbstractsPesticide use in ornamental production: what are the benefits?PEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 4 2009James A Bethke Abstract Pest control in ornamental production is challenging owing to the diversity of crops grown, the desired aesthetic perfection, the potential economic loss due to failure and the multitude of arthropod pests encountered. Agricultural crops of less value per acre, such as row crops, can tolerate a certain level of damage from arthropod pests without compromising yields. Damage thresholds for ornamentals, however, are essentially zero. Pesticides are a viable method of protection for such a crop in lieu of alternatives. Therefore, the purpose of this paper is to emphasize the importance of pesticides to the ornamental industry. Pesticides provide many benefits to ornamental producers, including: (1) consistent availability; (2) rapid kill; (3) reliable and consistent control; (4) increased crop production and quality; (5) they may be used to prevent movement of invasive pests; (6) they are less expensive (in general) than alternatives; (7) they may reduce plant pathogenic transmission; (8) they may be used in conjunction with natural enemies. Pesticide use will continue to be a significant strategy for dealing with arthropod pests so that ornamental producers can stay competitive in both national and international markets. Copyright © 2009 Society of Chemical Industry [source] Laser-induced damage of DKDP crystal under different wavelengthsCRYSTAL RESEARCH AND TECHNOLOGY, Issue 7 2010Mingxia Xu Abstract In this paper, DKDP crystals were grown from 80% deuterated solution by traditional temperature-reduction method. The crystal samples were selected to test laser damage threshold (LDT) and laser conditioning of 1,, 2, and 3,. We found that the laser conditioning of 3, has much more effect on improving the LDT. The damage site was observed by microscope and its effects on micro-structure and optical properties were also studied. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] The effect of material, thermal and laser conditioning on the damage threshold of type II tripler-cut DKDP crystalsCRYSTAL RESEARCH AND TECHNOLOGY, Issue 7 2008Shao-Tao Sun Abstract By using the traditional temperature-reduction method, KD2PO4 (DKDP) crystals were grown from 85%-deuterated aqueous solution synthesized by different kind of KH2PO4 (KDP) raw materials. An experimental technique was employed to measure the variation of bulk damage threshold in plates of DKDP crystals. Bulk laser damage in unconditioned, thermal-conditioned and laser-conditioned type II tripler-cut DKDP crystals has been studied using 1064 nm (,) and 355 nm (3,) laser at pulse lengths of 5ns, 5ns respectively. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Growth and characterization of La3Ga5.5Ta0.5O14 crystalCRYSTAL RESEARCH AND TECHNOLOGY, Issue 8 2004Haikuan Kong Abstract La3Ga5.5Ta0.5O14 (LGT) crystal was grown by using the Czochralski method. The as-grown crystal is transparent, free from inclusions and with no cracks. Specific heat, thermal expansion, dielectric constants, transmission spectrum and optical damage threshold of LGT have been measured, and the results show general properties of LGT are similar to that of La3Ga5SiO14 (LGS) crystal. The experiment to research the Q-switch properties of LGT has been performed and the results show LGT possesses smaller electrooptic coefficients than that of LGS and may not be an ideal material used as a Q-switch. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Acceptable prior fatigue damage and failure threshold for impact loading of an aluminium alloyFATIGUE & FRACTURE OF ENGINEERING MATERIALS AND STRUCTURES, Issue 1 2001T. Auzanneau In a competitive economic context that aims at gains in safety, some problems of combined fatigue-impact loadings are crucial, particularly in the case of light alloys used in the transport and aeronautical industries. One important challenge is to quantify the fatigue preloading effect on the residual dynamic plasticity of a 2017-A T3 aluminium alloy. From an experimental modal analysis, the change in mechanical properties of prefatigued material under impact loading allows us to define the best mechanical parameter for a limiting threshold between a no-damage state and weakened states due to fatigue predamage. For this situation a hybrid technique has been developed. A numerical model including voids (which represent surface micro-cracks produced by the fatigue preloading) is fitted to the results obtained by the modal analysis of the damaged sample. Hence, an acceptable damage threshold (i.e. a damage critical volume below which the impact toughness is not affected by fatigue preloading) and a failure threshold are established. On the basis of this methodology, it is possible to predict the energy required for the impact failure of prefatigued specimens and therefore to predict a safe or a dangerous mechanical state. [source] Inundative release of coccinellid beetles into eucalypt plantations for biological control of chrysomelid leaf beetlesAGRICULTURAL AND FOREST ENTOMOLOGY, Issue 2 2003Susan C. Baker Abstract 1,Inundative augmentative releases of adult coccinellid beetles were assessed for their potential to effectively supplement biological control of outbreak populations of the Eucalyptus leaf beetle Chrysophtharta bimaculata in Eucalyptus nitens plantations. 2,Mixed groups of two species of overwintering coccinellids, Cleobora mellyi and Harmonia conformis, were collected from the field then fed three diets in the laboratory prior to release. Both species were released in the summer into two E. nitens plantations with economically damaging Chrysophtharta populations. 3,Differences between dispersal of coccinellids fed the three diets were slight; beetles brought straight out of overwintering before release were initially slower moving onto trees. 4,Numbers of coccinellids on trees in monitoring plots decreased exponentially with time, and populations had returned to prerelease levels 7 days after release. The number of coccinellids recaptured decreased with increasing distance from the release point with very few coccinellids per tree at 70 m distance. Dispersal of C. mellyi away from the release plot was slower than that of H. conformis. 5,Numbers of coccinellids on trees were significantly related to predation levels of C. bimaculata with a large decrease in the C. bimaculata population to below the economic damage threshold in plots where the numbers of coccinellids were high. 6,The results of this study suggest that inundative release of laboratory reared coccinellids is possible for biological control of C. bimaculata, although it may only be economically viable in small, environmentally sensitive areas. [source] Investigation of the combustion process in an auxiliary heating system using dual-pump CARSJOURNAL OF RAMAN SPECTROSCOPY, Issue 6 2006A. Braeuer Abstract A dual-pump coherent anti-Stokes Raman spectroscopy (CARS) setup was used for the simultaneous determination of temperature and oxygen/nitrogen ratio in an automotive auxiliary heating system. The auxiliary heating system was equipped with eight windows to provide four line-of-sight optical accesses at two different downstream levels. The usable laser pulse energies, which are essentially limited by the damage threshold of the glass windows, were increased by the application of an optical pulse stretcher. Measurements were performed for standard diesel fuel for full- and part-load operation as well as for the model fuel n -dodecane for full-load operation. The n -dodecane measurements can directly be compared with numerical predictions, whereas the results for diesel fuel provide information about the possibility of transfer of the n -dodecane simulations to real fuel conditions. Copyright © 2006 John Wiley & Sons, Ltd. [source] Hybrid germanium/silica optical fibers for endoscopic delivery of erbium:YAG laser radiationLASERS IN SURGERY AND MEDICINE, Issue 1 2004Charles A. Chaney MS Abstract Background and Objectives Endoscopic applications of the erbium (Er):YAG laser have been limited due to the lack of an optical fiber delivery system that is robust, flexible, and biocompatible. This study reports the testing of a hybrid germanium/silica fiber capable of delivering Er:YAG laser radiation through a flexible endoscope. Study Design/Materials and Methods Hybrid optical fibers were assembled from 1-cm length, 550-,m core, silica fiber tips attached to either 350- or 425-,m germanium oxide "trunk" fibers. Er:YAG laser radiation (,,=,2.94 ,m) with laser pulse lengths of 70 and 220 microseconds, pulse repetition rates of 3,10 Hz, and laser output energies of up to 300 mJ was delivered through the fibers for testing. Results Maximum fiber output energies measured 180±30 and 82±20 mJ (n,=,10) under straight and tight bending configurations, respectively, before fiber interface damage occurred. By comparison, the damage threshold for the germanium fibers without silica tips during contact soft tissue ablation was only 9 mJ (n,=,3). Studies using the hybrid fibers for lithotripsy also resulted in fiber damage thresholds (55,114 mJ) above the stone ablation threshold (15,23 mJ). Conclusions Hybrid germanium/silica fibers represent a robust, flexible, and biocompatible method of delivering Er:YAG laser radiation during contact soft tissue ablation. However, significant improvement in the hybrid fibers will be necessary before they can be used for efficient Er:YAG laser lithotripsy. Lasers Surg. Med. 34:5,11, 2004. © 2004 Wiley-Liss, Inc. [source] Pulsed electrical stimulation for control of vasculature: Temporary vasoconstriction and permanent thrombosisBIOELECTROMAGNETICS, Issue 2 2008Daniel Palanker Abstract A variety of medical procedures is aimed to selectively compromise or destroy vascular function. Such procedures include cancer therapies, treatments of cutaneous vascular disorders, and temporary hemostasis during surgery. Currently, technologies such as lasers, cryosurgery and radio frequency coagulation, produce significant collateral damage due to the thermal nature of these interactions and corresponding heat exchange with surrounding tissues. We describe a non-thermal method of inducing temporary vasoconstriction and permanent thrombosis using short pulse (microseconds) electrical stimulation. The current density required for vasoconstriction increases with decreasing pulse duration approximately as t,0.25. The threshold of electroporation has a steeper dependence on pulse duration,exceeding t,0.5. At pulse durations shorter than 5,µs, damage threshold exceeds the vasoconstriction threshold, thus allowing for temporary hemostasis without direct damage to surrounding tissue. With a pulse repetition rate of 0.1,Hz, vasoconstriction is achieved approximately 1 min after the beginning of treatment in both arteries and veins. Thrombosis occurs at higher electric fields, and its threshold increases with vessel diameter. Histology demonstrated a lack of tissue damage during vasoconstriction, but vascular endothelium was damaged during thrombosis. The temperature increase does not exceed 0.1,°C during these treatments. Bioelectromagnetics 29:100,107, 2008. © 2007 Wiley-Liss, Inc. [source] Ips typographus (L.) pheromone trapping in south Alps: spring catches determine damage thresholdsJOURNAL OF APPLIED ENTOMOLOGY, Issue 4 2004M. Faccoli Abstract:,Ips typographus is one of the major forest pests in the Italian Alps. From 1996, populations of I. typographus in Friuli-Venezia Giulia region (NE Italy) have been permanently monitored in areas of outbreak by using pheromone traps. At the same time, damage caused by the insect was estimated annually. Preliminary analysis of the data (1996,2002) reveals some interesting information: (i) the flight activity of I. typographus is very extended and occurs over a period of about 4 months (May to August); (ii) there is a high correlation between mean captures per trap and annual damage; (iii) there is a high correlation between spring captures (May to mid-June) and total captures (May to August), and between spring captures (May to mid-June) and annual damage. The correlation between spring captures and damage allows the determination of a reliable risk-damage threshold (about 5000 beetles/trap, in spring), reducing at the same time, the monitoring period and the general costs. [source] Comparison of germanium oxide fibers with silica and sapphire fiber tips for transmission of erbium: YAG laser radiationLASERS IN SURGERY AND MEDICINE, Issue 8 2006Travis J. Polletto BS Abstract Background and Objectives Endoscopic applications of the Erbium:YAG laser have been limited due to the lack of a suitable optical fiber delivery system. The purpose of this study was to compare the transmission of Er:YAG laser radiation through germanium oxide trunk fibers with silica and sapphire fiber tips for potential use in contact tissue ablation during endoscopy. Study Design/Materials and Methods Er:YAG laser radiation with a wavelength of 2.94 µm, pulse length of 300 microseconds, pulse energies from 5 to 1,360 mJ, coupled into pulse repetition rates of 3,10 Hz, was through 1-m-long germanium oxide fibers with either 1-cm-long, 550-µm-diameter silica or sapphire tips. Results Transmission through the germanium oxide/sapphire fibers measured 65±5% compared with 55±4% for the germanium oxide/silica fibers (P<0.05). The damage threshold for the hybrid fibers averaged 309± 44 mJ and 126±43 mJ, respectively (n,=,7 fibers each) (P<0.05). The highest pulse energies transmitted through the fibers were 700 mJ and 220 mJ, respectively. Conclusions Improved index-matching of the trunk fiber and fiber tip at 2.94 µm resulted in higher transmission and damage thresholds for the germanium oxide/sapphire fibers. The germanium oxide/sapphire fiber may represent a promising mid-infrared optical fiber delivery system for use in endoscopic applications of the Er:YAG laser requiring a flexible, biocompatible, and robust fiber delivery system for contact tissue ablation. Lasers Surg. Med. 38:787,791, 2006. © 2006 Wiley-Liss, Inc. [source] Hybrid germanium/silica optical fibers for endoscopic delivery of erbium:YAG laser radiationLASERS IN SURGERY AND MEDICINE, Issue 1 2004Charles A. Chaney MS Abstract Background and Objectives Endoscopic applications of the erbium (Er):YAG laser have been limited due to the lack of an optical fiber delivery system that is robust, flexible, and biocompatible. This study reports the testing of a hybrid germanium/silica fiber capable of delivering Er:YAG laser radiation through a flexible endoscope. Study Design/Materials and Methods Hybrid optical fibers were assembled from 1-cm length, 550-,m core, silica fiber tips attached to either 350- or 425-,m germanium oxide "trunk" fibers. Er:YAG laser radiation (,,=,2.94 ,m) with laser pulse lengths of 70 and 220 microseconds, pulse repetition rates of 3,10 Hz, and laser output energies of up to 300 mJ was delivered through the fibers for testing. Results Maximum fiber output energies measured 180±30 and 82±20 mJ (n,=,10) under straight and tight bending configurations, respectively, before fiber interface damage occurred. By comparison, the damage threshold for the germanium fibers without silica tips during contact soft tissue ablation was only 9 mJ (n,=,3). Studies using the hybrid fibers for lithotripsy also resulted in fiber damage thresholds (55,114 mJ) above the stone ablation threshold (15,23 mJ). Conclusions Hybrid germanium/silica fibers represent a robust, flexible, and biocompatible method of delivering Er:YAG laser radiation during contact soft tissue ablation. However, significant improvement in the hybrid fibers will be necessary before they can be used for efficient Er:YAG laser lithotripsy. Lasers Surg. Med. 34:5,11, 2004. © 2004 Wiley-Liss, Inc. [source] | |||||||||||||