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Testing semiochemicals from aphid, plant and conspecific： attraction of Harmonia axyridis

Insect Science 2012年第3期19卷 372-382页

作者： Pascal D. Leroy Thomas Schillings Julien Farmakidis Stephanie Heuskin Georges Lognay Francois J. Verheggen Yves Brostaux Eric Haubruge Frederic Francis Departments of Functional and Evolutionary Entomology Departments of Analytical Chemistry Departments of Applied Statistics Computer Science and Mathematics University of Liege Gembloux Agro-Bio Tech Gembloux Belgium

Harmonia axyridis Pallas （Coleoptera： Coccinellidae） is an invasive specie affecting the dynamics and composition of several guilds. Nowadays, no biological control method is available to reduce the populations of this harmful coccinellid. Attractants and semiochemicals seem to be the best alternative but only few studies have tested the impact of semiochemicals on this Asian lady beetle. In this work, through wind- tunnel experiments, semiochemicals from aphids （Z,E-nepetalactone, [E]-β-farnesene, a-pinene and β-pinene）, from coccinellids （[-]-β-earyophyllene） and from the nettle Urtica dioica L. were evaluated as potential attractants. The nettle volatile compounds （[Z]-3- hexenol and [E]-2-hexenal） were extracted using a Clevenger Apparatus and identified by headspace gas chromatography-mass spectroscopy. In the wind-tunnel experiments, the main components of the aphid alarm pheromone as well as a component of the aphid sexual pheromone strongly attracted both sexes of the Asian lady beetle while （-）-β- caryophyllene only attracted few individuals and had no impact on the males. The nettle extract as well as the （Z）-3-hexenol oriented both males and females to the odor source. The （E）-2-hexenal was shown to have no effect on females even if this green leaf volatile attracted males. Because Z,E-nepetalactone was identified as the most efficient attractant in the wind-tunnel experiments, this volatile was also tested in a potato field where H. axyridis has been showed to respond to this semiochemical. This study highlighted that Z,E-nepetalactone orientated the Asian lady beetle H. axyridis under natural condi- tions, indicating that this volatile compound could certainly help for an efficient biological control approach against this invasive specie.

关键词： aphids attractant Harmonia axyridis plant semiochemicals wind-tunnel

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Combating wind erosion through soil stabilization under simulated wind flow condition -Case of Kuwait

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International Soil and Water Conservation Research 2020年第2期8卷 154-163页

作者： Hana'a Burezq Desert Agriculture and Ecosystems Program(DAEP) Environment and Life Sciences Research Center(ELSRC)Kuwait Institute for Scientific Research(KISR)P.O.Box 24885 Safat13109Kuwait

The soil survey of Kuwait has revealed the landscapes dominated by loose sandy material, that are vulnerable to wind erosion. Globally three modes of soil particle movement (creep, saltation & sus-pension) by wind have been recognized. To evaluate these modes in the deserts of Kuwait, sixty surface soil samples were collected and analyzed for particle sizes to quantify relative occurrence of modes of particle movement in the deserts of Kuwait. This analysis revealed distribution of particles in the size ranges, as follows: saltation (70%) > Creep (20%) > Suspension (10%) confirming saltation is the main mode of soil movement. This has provided basic information to set up a pilot scale experiment to reduce the wind erosion rate through sand stabilization using various sand binding products in three treat-ments;T1 (native sandy soil);T2 (sand mixed with biochar and animal manure);T3 (sand mixed with biochar, animal manure, Urea Formaldehyde (UF), Sulfonated Naphthalene Formaldehyde (SNF), and Poly Vinyl Alcohol (PVA). The results showed that the erosion rate of native sandy soil (T1) has increased from 3.33, 4.77 to 7.35 g/(m2. min) when wind speed was increased from 5, 10 to 15 m/s, respectively. At the same wind speeds, the measured erosion loss was 1.99, 3.07, 5.32 g/(m2. min) in T2 and 1.17, 2.6, 4.24 g/(m2. min) in T3. From these results, it can be concluded that there is a possibility to reduce wind erosion in the deserts of Kuwait through sand stabilization and save the deserts from further degradation.

关键词： Biodegradable-product BiocharSoil-stability wind-erosion wind-tunnel Saltation

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Experimental Investigation of Spoiler Deployment on Wing Stall

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Open Journal of Fluid Dynamics 2018年第3期8卷 308-320页

作者： Scott Douglas Lindsay Paul Walsh Ryerson University Toronto Canada

Upper surface wing flaps, known as spoiler, are typically used to reduce lift and increase drag at touchdown;however spoilers have been shown to increase lift and reduce drag at near-stall conditions. The purpose of this experiment was to determine the spoilers’ impact on lift, drag, moment, and aerodynamic efficiency of a NACA 2412 airfoil at angles of attack (α) from −8 ° to 32 °. The experiment was conducted in the Ryerson Low-Speed wind tunnel (closed-circuit, 1 m × 1 m test section) at Re=783761, Ma=0.136. The lift coefficient (Cl), drag coefficient (Cd), moment coefficient about the quarter-chord () were captured with a changing spoiler deflection angle (δ) and spoiler length (b in percent chord). It was found that deflecting the spoiler resulted in an increase maximum lift of up to 2.497%. It was found that deflecting the spoiler by 8° was optimal for the b=10 cases. Any larger deflection reduced the lift gain, and a deflection of 25° caused the maximum lift to be 2.786% less than the clean configuration. In the b=15 case, δ=15° was optimal (1.760% maximum lift coefficient increase). The b=10 cases increased maximum lift coefficient between 0.35% and 2.10% higher than the b=15 cases. The source of the lift gain at high angles of attack is apparent in an analysis of the airfoil pressure distribution. The spoiler increased the suction peak on the airfoil surface upstream of the spoiler, and increased the pressure downstream. However the suction increase upstream is larger than the pressure increase downstream, resulting in a net increase in lift. The spoiler increased the stall angle 37.658% to 87.658% higher than the clean configuration. Stall angle increased with both δ and with an increased spoiler length. The spoiler airfoil produced less drag than the clean configuration at high angles of attack. The combination of the increased lift, and reduced drag resulted in an increase in aerodynamic efficiency at high angle of attack.

关键词： Aircraft Stall wind-tunnel Spoilers Low-Speed Aerodynamics

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