Impacts of transgenic Bt cotton on the stylet penetration behaviors of Bemisia tabaci biotype B Evidence from laboratory experiments

Stylet penetration behaviors of Bemisia tabaci biotype B on two transgenic cotton lines ＂GK12＂ and ＂GK19＂ expressing Bt toxic protein CrylA （Bt cotton） and a non-Bt conventional cotton line ＂Simian-3＂ （CK cotton） were recorded with the direct current electrical penetration graph （DC-EPG） technique. Our results suggested that EPG waveform patterns, types and characteristics [non-probe （NP）, pathway （C）, potential drops （pd） and phloem phase （E（pd））] ofBemisia tabaci biotype B were very similar on the three cotton lines. There were no obvious differences of pathway variables among whiteflies on the three cotton lines. Some phloem variables related to E（pd）l differed. Duration of 1st E（pd）l and mean duration of E（pd）l on both GK12 and GK19 were significantly shorter than that on CK cotton （P 〈 0.05）. Fewer whiteflies on GK have long E（pd）l. Other phloem variables including total duration of E（pd） summed, mean E（pd） duration and percentage of whiteflies reaching the phloem phase were similar among the three cotton lines.

Stylet penetration behaviors of the cotton aphid Aphis gossypfi on transgenic Bt cotton

Stylet penetration behaviors of cotton aphids Aphis gossypii Glover on a transgenic cotton line ＂GK-12＂ expressing Bt toxic protein of Cry 1A （Bt cotton） and a non- Bt conventional cotton line ＂Simian-3＂ （CK cotton） were recorded with the direct current electrical penetration graph （DC-EPG） technique. Cotton aphids reared on Bt cotton （abbreviated as Bt-aphids） and its parental non-Bt control line （CK-aphids） for more than 20 generations each, were used for recordings on two cotton lines. Among 47 selected parameters reflecting the activities of aphid stylets within plant tissues, there were eight parameters of CK-aphids showing significant differences between the performances of CK- aphids on Bt cotton and CK cotton, while for Bt-aphids, all the parameters were statistically equal between the performances on the two cotton lines. All parameters with significant differences indicated that CK-aphids could penetrate into Bt cotton more easily, but the phloem saps of Bt cotton were not as good as those of regular cotton for CK-aphids. Based on the present results, we concluded that there were some factors in Bt cotton affecting penetration behaviors of CK-aphids, but it just took several generations for CK-aphids to completely adapt Bt cotton, and Bt-aphids could feed on two cotton lines without difficulty.

Reaction characteristic of PTFE/Al/Cu/Pb composites and application in shaped charge liner

In this paper, the reaction characteristic and its application in shaped charge warhead of a novel reactive material, which introduced copper(Cu) and plumbum(Pb) into traditional polytetrafluoroethylene/aluminum(PTFE/Al), are studied. The thermal analysis and chemical reaction behavior of the PTFE/Al/Cu/Pb mixture are investigated by Differential Scanning Calorimetry(DSC),Thermo-gravimetry(TG), and Xray Diffraction(XRD) techniques. Then, the shaped charge liners with PTFE/Al/Cu/Pb reactive materials are fabricated, and the X-ray experiments show that they could form reactive jets with excellent performance under the detonation effects of the shaped charge. Based on that, the penetration experiments of shaped charge with PTFE/Al/Cu/Pb reactive liner against steel plates are carried out, and the results demonstrate that the PTFE/Al/Cu/Pb reactive jets could produce a deeper penetration depth compared to the traditional PTFE/Al reactive jets. Meanwhile, the PTFE/Al/Cu/Pb reactive jets also show significant inner-blast effects, leading to dramatically cracking or fragmentation behavior of the penetrated steel plates. This new PTFE/Al/Cu/Pb reactive liner shaped charge presents enhanced penetration behavior for steel targets that incorporates the penetration capability of a high-density and ductility jet, and the chemical energy release of PTFE-matrix reactive materials.

Implementation of OpenMP Parallelization of Rate-Dependent Ceramic Peridynamic Model

A rate-dependent peridynamic ceramic model,considering the brittle tensile response,compressive plastic softening and strain-rate dependence,can accurately represent the dynamic response and crack propagation of ceramic materials.However,it also considers the strain-rate dependence and damage accumulation caused by compressive plastic softening during the compression stage,requiring more computational resources for the bond force evaluation and damage evolution.Herein,the OpenMP parallel optimization of the rate-dependent peridynamic ceramicmodel is investigated.Also,themodules that compute the interactions betweenmaterial points and update damage index are vectorized and parallelized.Moreover,the numerical examples are carried out to simulate the dynamic response and fracture of the ceramic plate under normal impact.Furthermore,the speed-up ratio and computational efficiency by multi-threads are evaluated and discussed to demonstrate the reliability of parallelized programs.The results reveal that the totalwall clock time has been significantly reduced after optimization,showing the promise of parallelization process in terms of accuracy and stability.

Effect of Chromite-Silica Sands Characteristics on Performance of Ladle Filler Sands for Continuous Casting

Free opening rate is mainly determined by the performance of the ladle filler sand. High free opening rates of ladles are required in steel making to improve steel quality. Chromite ladle filler sands are one of the most widely used ladle filler sand. Several operative variables and materials characteristics affect the performance of the sands. Three sets of chromite ladle filler sands were selected and researches were focused on the sintering hehaviour and per- formance of the sands under operative conditions. The effect of particle size distribution on sintering, microstruc- ture, flowability, and permeability were presented. In all cases, the particle size varies from 0.1 to 1.5 mm corre- sponding to free flowing powders. One of the samples has higher permeability factor in comparison with others due to low particle size distribution. The other sample presents very good free opening due to its very good flowability and permeability factor.