Extended Kalman filter based sliding mode control of parallel-connected two five-phase PMSM drive system

This paper presents sliding mode control of sensor-less parallel-connected two five-phase permanent magnet synchronous machines (PMSMs) fed by a single five-leg inverter. For both machines, the rotor speeds and rotor positions as well as load torques are estimated by using Extended Kalman Filter (EKF) scheme. Fully decoupled control of both machines is possible via an appropriate phase transposition while connecting the stator windings parallel and employing proposed speed sensor-less method. In the resulting parallel-connected two-machine drive, the independent control of each machine in the group is achieved by controlling the stator currents and speed of each machine under vector control consideration. The effectiveness of the proposed Extended Kalman Filter in conjunction with the sliding mode control is confirmed through application of different load torques for wide speed range operation. Comparison between sliding mode control and PI control of the proposed two-motor drive is provided. The speed response shows a short rise time, an overshoot during reverse operation and settling times is 0.075 s when PI control is used. The speed response obtained by SMC is without overshoot and follows its reference and settling time is 0.028 s. Simulation results confirm that, in transient periods, sliding mode controller remarkably outperforms its counterpart PI controller. 2018 by the authors.Scopu

The Banana stem weevil Odoiporus longicollis

The banana stem weevil Odoiporus longicollis; Le charançon du pseudotronc du bananier Odoiporus longicollis; El barrenador del tallo del banano Odoiporus longicolli

Electrophysiological responses of banana pseudostem weevil, Odoiporus longicollis Olivier (Coleoptera: Curculionidae) to methyl jasmonate, 1-hexanol and host plant extract

53-57The banana pseudostem weevil (BSW), Odoiporus longicollis Olivier (Coleoptera: Curculionidae) is one of the most destructive pests of banana and plantains. Our laboratory bioassay studies showed that out of 50 host plants related volatile chemicals screened against BSW, only methyl jasmonate (MeJA) and 1-hexanol was electrophysiologically and behaviourally active. Here, we investigated the influence of host plant extract (HPE) on two semiochemicals, namely methyl jasmonate (MeJA) and 1-hexanol, both independently and in combination, in the electroantennogram (EAG) response in BSW. The results showed that HPE alone elicited greater EAG response only in males suggesting that males involved predominantly in the host plant selection. Addition of HPE to MeJA increased significantly higher EAG response in females and the response was insignificant in males. Similarly, the addition of HPE to 1-hexanol evoked higher response in females but decreased antennal activity was recorded in males compared to HPE alone. The HPE showed additive effect on MeJA and 1-hexanol in their EAG responses only in female BSW. The result also revealed that 1-hexanol+HPE blend exhibited enhanced EAG response compared to 1-hexanol alone in both sexes

SCREENING AND CHARACTERIZATION OF DEVELOPING RESISTANT CULTIVAR AGAINST ODOIPORUS LONGICOLLIS (OLIVIER) (COLEOPTERA: CURCULIONIDAE) USING REFERENCE GENOTYPES IN INDIA

Objective: The objective of the research was to develop a screening method for weevil resistance by using selected genotypes. The selected reference genotypes were screened against stem weevil to deals with the different parts in India.Methods: The collected stem pieces of each cultivar were cut into 30 cm length and kept in an insect breeding chamber for two polypropylene cages is one into another. The bottom of the inner cage is made holes to drain the water from stem discs and the outer cage is without holes to collect it. Reproductively active and healthy weevils (4 females and 4 males) were selected and released into the breeding chamber for each commercial cultivar and screened against Odoiporus longicollis and observation was taken after 38 d. Based on the following method, different states of insect cultures were screened under in vitro conditions. This experiment was replicated four times for further statistical analysis.Results: The resistant genotype had significantly more (p<0.05) mortality, and fewer than the susceptible genotypes. These results indicated that the genotypes can be used as reference genotypes in evaluating resistance or susceptibility against the banana stem weevil using Gas chromatography with antennogram detector. This implies that the infestation caused by the weevils varied in different genotypes and also this information will be further helpful in selecting the resistant cultivars for future in the field of Agriculture.Conclusion: In commercial cultivars, no one can report the divergent and screening of stem weevil under in vitro conditions. In field conditions, that are not accuracy because, Climate change, Adaptation of host, migration and etc. For this instance, we performed the in vitro screening study and it finally revealed the susceptible and resistant genotypes based on the percent of weevil infestation are the same as well as no significant differences between different banana growing areas in India.Keywords: Banana stem weevil (Odoiporus longicollis), Screening, Host-plant resistance, Resistant genotypes, Biodiversity, Gas chromatography with Electroantennogram detector (GC-EAD

Corrosion and Tribological Characteristics of FSPed Aluminum Alloy AA5052

Friction stir processing (FSP) is a solid-state and effective process for surface modification of aluminium alloys. In this study the AA5052 alloy, widely used in marine applications, has been subjected to FSP. The FSP trials have been carried out by altering the FSP process parameters (tool rotation speed, tool traverse speed, and shoulder diameter). The friction stir processed specimens have been characterised / tested for microstructure, microhardness, sliding wear, immersion corrosion, and electrochemical corrosion. The hybrid polynomial – radial basis function-based models have been developed to determine the relationship between the process parameters and the evaluated properties. Furthermore, the optimum parameters for obtaining high hardness, wear resistance, and corrosion resistance have been determined. Microstructure evaluation in the friction stir processed specimens has shown refinement and uniform dispersion of β particles throughout the α-Al matrix. The results show that the improvement in properties is a result of the homogeneous dispersion of secondary β phase particles in the matrix. Friction stir processing of AA5052 alloy has improved hardness by ~14.5%, wear resistance by ~83%, and corrosion resistance ~87%. The optimum process window for friction stir processing of AA5052 alloy is tool rotation speed between 500 rpm and 900 rpm, tool traverse speed between 10 mm/min and 30 mm/min, and tool shoulder diameter of 18 mm and 21 mm

Electrophysiological responses of banana pseudostem weevil,Odoiporus longicollis Olivier (Coleoptera: Curculionidae) tomethyl jasmonate, 1-hexanol and host plant extract

The banana pseudostem weevil (BSW), Odoiporus longicollis Olivier (Coleoptera: Curculionidae) is one of the mostdestructive pests of banana and plantains. Our laboratory bioassay studies showed that out of 50 host plants related volatilechemicals screened against BSW, only methyl jasmonate (MeJA) and 1-hexanol was electrophysiologically and behaviourallyactive. Here, we investigated the influence of host plant extract (HPE) on two semiochemicals, namely methyl jasmonate(MeJA) and 1-hexanol, both independently and in combination, in the electroantennogram (EAG) response in BSW. The resultsshowed that HPE alone elicited greater EAG response only in males suggesting that males involved predominantly in the hostplant selection. Addition of HPE to MeJA increased significantly higher EAG response in females and the response wasinsignificant in males. Similarly, the addition of HPE to 1-hexanol evoked higher response in females but decreased antennalactivity was recorded in males compared to HPE alone. The HPE showed additive effect on MeJA and 1-hexanol in their EAGresponses only in female BSW. The result also revealed that 1-hexanol+HPE blend exhibited enhanced EAG responsecompared to 1-hexanol alone in both sexes

Large-amplitude isothermal fluctuations and high-density dark-matter clumps

Large-amplitude isothermal fluctuations in the dark matter energy density, parameterized by \Phi\equiv\delta\rhodm/\rhodm, are studied within the framework of a spherical collapse model. For \Phi \ga 1, a fluctuation collapses in the radiation-dominated epoch and produces a dense dark-matter object. The final density of the virialized object is found to be \rho_F \approx 140\, \Phi^3 (\Phi+1) \rhoeq, where \rhoeq is the matter density at equal matter and radiation energy density. This expression is valid for the entire range of possible values of $\Phi$, both for $\Phi \gg 1$ and $\Phi \ll 1$. Some astrophysical consequences of high-density dark-matter clumps are discussed.Comment: 15 pages plus 3 figures (included at the end as a uuencoded postscript file), LaTeX, FNAL--PUB--94/055--