Position control of electro-hydraulic actuator system using fuzzy logic controller optimized by particle swarm optimization

The position control system of an electro-hydraulic actuator system (EHAS) is investigated in this paper. The EHAS is developed by taking into consideration the nonlinearities of the system: the friction and the internal leakage. A variable load that simulates a realistic load in robotic excavator is taken as the trajectory reference. A method of control strategy that is implemented by employing a fuzzy logic controller (FLC) whose parameters are optimized using particle swarm optimization (PSO) is proposed. The scaling factors of the fuzzy inference system are tuned to obtain the optimal values which yield the best system performance. The simulation results show that the FLC is able to track the trajectory reference accurately for a range of values of orifice opening. Beyond that range, the orifice opening may introduce chattering, which the FLC alone is not sufficient to overcome. The PSO optimized FLC can reduce the chattering significantly. This result justifies the implementation of the proposed method in position control of EHAS.     

Synthesis and characterisation of neem leaf extract, 2, 3‐dehydrosalanol and quercetin dihydrate mediated silver nano particles for therapeutic applications

The utility of green silver nanoparticles (AgNPs) in veterinary medicine is steadily increasing as they have many therapeutic applications against pathogens and arthropods of livestock. In this study, green AgNPs using neem (N‐AgNPs), 2,3‐dehydrosalanol (2,3‐DHS‐AgNPs) and quercetin dihydrate (QDH‐AgNPs) were synthesised and characterised. Synthesised compounds were characterised by UV‐Vis spectroscopy and the peak absorbance was recorded at 370 nm for neem extract. For N‐AgNPs, 2,3‐DHS‐AgNPs and QDH‐AgNPs, the maximum absorbance peaks were at 430, 230 and 220 nm, respectively. The FTIR analysis confirmed the synthesis of green AgNPs. The XRD pattern of N‐AgNPs showed the peaks corresponding to whole spectra of 2 θ values ranging from 10–80. The relatively higher intensity of (111, 222) planes in face centred cubic crystalline structure supports the formation of synthesised AgNPs. In DLS analysis, the hydrodynamic diameter of neem leaf extract was found to be 259.8 nm, followed by 5.3, 6.7 and 261.8 nm for 2,3‐DHS‐AgNPs, N‐AgNPs and QDH‐AgNPs, respectively. Based on the transmission electron microscopy and scanning electron microscopy image analyses, confirmed the formation of N‐AgNPs, 2,3‐DHS‐AgNPs and QDH‐AgNPs. These eco‐friendly phyto‐AgNPs may be of use as an effective alternative to chemical control methods against the arthropods of livestock.Inspec keywords: nanoparticles, silver, nanomedicine, biomedical materials, nanofabrication, Fourier transform infrared spectra, ultraviolet spectra, visible spectra, X‐ray diffraction, light scattering, transmission electron microscopy, scanning electron microscopy, aggregation, veterinary medicineOther keywords: 2,3‐dehydrosalanol mediated silver nanoparticles, quercetin dihydrate mediated silver nanoparticles, therapeutic applications, green silver nanoparticles, veterinary medicine, Azadirachta indica, UV‐visible spectroscopy, Fourier transformed infrared analysis, X‐ray diffraction, (111) planes, (222) planes, face centred cubic crystalline structure, dynamic light scattering, hydrodynamic diameter, aqueous neem leaf extract, transmission electron microscopy, hexagonal shape, pencil head shape, cuboid shape, scanning electron microscopy, aggregation, arthropod infesting livestock, Ag, in‐vivo antiectoparasitic activity, in‐vitro antiectoparasitic activity     

Novel organic–inorganic hybrid coatings prepared by the sol–gel process: corrosion and mechanical properties

(Hyperbranched polyurethane‐urea)/[(3‐aminopropyl)triethoxysilane]‐ZnO (HBPUU‐APTES‐ZnO) hybrid coatings were synthesized using an inexpensive mixing technique by varying the APTES‐modified ZnO concentration. The mechanical and surface properties of the hybrid coating films were studied and compared with unmodified and modified ZnO. The corrosion, solvent and abrasion resistance show significant enhancement in HBPUU‐APTES‐ZnO hybrids and their properties are increased with increasing APTES‐ZnO concentration. This hybrid coating has opened up an opportunity for automotive topcoat application. Copyright © 2012 Society of Chemical Industry     

Investigation of the effect of ZnO nanoparticles on the thermomechanical and microbial properties of hyperbranched polyurethane‐urea hybrid composites

Hybrid coatings of hyperbranched polyurethane‐urea (HBPUU) containing ZnO nanoparticles were prepared by mixing the hyperbranched polyurethane with the nanoparticles. The films were stored at room temperature and laboratory humidity conditions for one week to yield completely cured hybrid films. The ZnO nanoparticles were found to be well dispersed in the polymer up to 3 wt%. The structure–property relationship of various HBPUU–ZnO hybrid coatings was analysed using a Fourier transform infrared peak deconvolution technique with a Gaussian curve‐fitting procedure, while their viscoelastic, thermomechanical and surface morphology were studied using X‐ray diffraction, dynamic mechanical thermal analysis, thermogravimetric analysis, a universal testing machine, scanning electron microscopy, atomic force microscopy and contact angle instruments. The thermal stability and mechanical properties of the hybrid composite films improved with increasing ZnO content, which was believed to be due to thermal insulation in the presence of nanoparticles. Water contact angle data suggested that the hydrophobic character of the hybrid composites increased with increasing nanoparticle concentration. The antimicrobial property of the HBPUU–ZnO hybrid coatings was studied using the disc diffusion method. HBPUU–ZnO hybrid coatings showed good antimicrobial properties compared to HBPUU. Copyright © 2012 Society of Chemical Industry     

Lower bounds to limit pressures of a tee-intersection of cylindrical shells based on a three-dimensional stress field

A lower bound to the limit pressure of a tee is based on three-dimensional stresses expanded in series which satisfy the equilibrium condition of branch and pipe automatically. The coefficients of the series are determined from the continuity condition of stress across the surface of intersection of branch and piping using partly the power series method and partly the point collocation least square method. The bounds are in agreement with experimental results of three limit pressure tests on tees conducted by the authors. The standard error calculated for the residuals of the overdetermined set of equations generated by the least square method is acceptable. However, high residuals at a few collocation points render the bounds too low for design if diameter ratios of the cylinders are smaller than 0.5 and a much more completed analysis is needed to improve this.     

Lipase‐mediated preparation of epoxy lecithin and its evaluation as plasticizer in polyester laminates

A simple chemoenzymatic method was developed for the preparation of epoxy lecithin that contains epoxy oils and phospholipids. The parameters such as lipase concentration, hydrogen peroxide concentration, and time of the reaction were studied. The product was evaluated as a plasticizer in polyester laminates and compared with virgin polyester laminates. The laminates were prepared using various amounts of epoxy lecithin and evaluated for different properties. The epoxy lecithin modified laminates showed good impact strength, tensile, and chemical resistance properties. These laminates were also evaluated for vicat softening point and water absorption. The epoxy lecithin can be used as a plasticizer in polyester laminates. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Modeling of Free Chlorine Consumption and Escherichia coli O157:H7 Cross‐Contamination During Fresh‐Cut Produce Wash Cycles

Controlling the free chlorine (FC) availability in wash water during sanitization of fresh produce enhances our ability to reduce microbial levels and prevent cross‐contamination. However, maintaining an ideal concentration of FC that could prevent the risk of contamination within the wash system is still a technical challenge in the industry, indicating the need to better understand wash water chemistry dynamics. Using bench‐scale experiments and modeling approaches, we developed a comprehensive mathematical model to predict the FC concentration during fresh‐cut produce wash processes for different lettuce types (romaine, iceberg, green leaf, and red leaf), carrots, and green cabbage as well as Escherichia coli O157:H7 cross‐contamination during fresh‐cut iceberg lettuce washing. Fresh‐cut produce exudates, as measured by chemical oxygen demand (COD) levels, appear to be the primary source of consumption of FC in wash water, with an apparent reaction rate ranging from L/mg·min for all produce types tested, at stable pH levels (6.5 to 7.0) in the wash water. COD levels increased over time as more produce was washed and the lettuce type impacted the rate of increase in organic load. The model parameters from our experimental data were compared to those obtained from a pilot‐plant scale study for lettuce, and similar reaction rate constant (5.38 × 10^-4 L/mg·min) was noted, supporting our hypothesis that rise in COD is the main cause of consumption of FC levels in the wash water. We also identified that the bacterial transfer mechanism described by our model is robust relative to experimental scale and pathogen levels in the wash water. Finally, we proposed functions that quantify an upper bound on pathogen levels in the water and on cross‐contaminated lettuce, indicating the maximum potential of water‐mediated cross‐contamination. Our model results could help indicate the limits of FC control to prevent cross‐contamination during lettuce washing.     

UV polymerization‐based surface modification technique for the production of bioactive packaging

The term bio‐active packaging refers to a packaging material that has been modified by the attachment or immobilization of bioactive components on the food contact surface. This article describes a novel, economical, and feasible technique for embedding bioactive components in energy curable food contact resins. While the technique is versatile and potentially applicable to any antimicrobial or bioactive compound; the proof of concept discussed in this article has focused on enzyme immobilization. Glucose oxidase (GOx) and catalase were used as representative enzymes. These oxidoreductases are very sensitive to inactivation by extrinsic factors and therefore present a challenging model for immobilization. Embedding of activity occurred via UV polymerization of commercial polymer coatings. The efficiency of immobilization and the performance of bioactive packaging were tested in both food simulants and actual food products. In both cases immobilization resulted in food contact surfaces with high retained enzyme activity as demonstrated by oxygen removal. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Discrimination of maize crop with hybrid polarimetric RISAT1 data

Microwave remote sensing provides an attractive approach to determine the spatial variability of crop characteristics. Synthetic aperture radar (SAR) image data provide unique possibility of acquiring data in all weather conditions. Several studies have used fully polarimetric data for extracting crop information, but it is limited by swath width. This study aimed to delineate maize crop using single date hybrid dual polarimetric Radar Imaging Satellite (RISAT)-1, Fine Resolution Stripmap mode (FRS)-1 data. Raney decomposition technique was used for explaining different scattering mechanisms of maize crop. Supervised classification on the decomposition image discriminated maize crop from other land-cover features. Results were compared with Resourcesat-2, Linear Imaging Self Scanner (LISS)-III optical sensor derived information. Spatial agreement of 91% was achieved between outputs generated from Resourcesat-2, LISS-III sensor and RISAT-1 data.     

Assessment of acaricidal activity of nanoscale ZnO encapsulated piperine formulation against Rhipicephalus microplus

This study aims to synthesise and evaluate the acaricidal activity of nanoscale zinc oxide piperine formulation (NZPF) against Rhipicephalus microplus ticks. NZPF was prepared by using zinc oxide nanoparticles (ZnONPs) and piperine by employing encapsulation technique; characterised by UV spectroscopy, Fourier transformed infrared analysis, X‐ray diffraction, dynamic light scattering, zetapotential and scanning electron microscopy. Acaricidal activity of the NZPF on R. microplus was evaluated using larval packet test (LPT) and adult immersion test (AIT). LPT against R. microplus larvae showed an LC₅₀ at 1 mg/l for NZPF followed by 2 and 3 mg/l for ZnONPs and piperine, respectively. AIT against R. microplus showed an LC₅₀ at concentration of 3 mg/l for NZPF followed by 6 mg/l for ZnONPs and 7 mg/l for piperine. In both LPT and AIT, LC₅₀ values of ZnONPs and NZPF were significantly lower compared to deltamethrin. NZPF showed significant ovulation inhibitory activity with lower IC₅₀ and IC₉₉ values compared to ZnONPs and piperine. NZPF has been proved to be the better alternative to routine chemical acaricides for control of tick infestation of cattle in the wake of acaricidal resistance, but safety issues need to be addressed before clinical application.Inspec keywords: molecular biophysics, pest control, ultraviolet spectra, X‐ray diffraction, zinc compounds, scanning electron microscopy, nanomedicine, agricultural engineering, agricultural safety, nanoparticles, light scattering, electrokinetic effects, encapsulation, Fourier transform infrared spectra, biotechnologyOther keywords: acaricidal activity, nanoscale zinc oxide piperine formulation, NZPF, Rhipicephalus microplus ticks, zinc oxide nanoparticles, ZnONP, LPT, adult immersion test, AIT, larval packet test, acaricidal resistance, UV spectroscopy, Fourier transformed infrared analysis, X‐ray diffraction, dynamic light scattering, zetapotential, scanning electron microscopy, ZnO