Pneumatic motor speed control by trajectory tracking fuzzy logic controller

In this study, trajectory tracking fuzzy logic controller (TTFLC) is proposed for the speed control of a pneumatic motor (PM). A third order trajectory is defined to determine the trajectory function that has to be tracked by the PM speed. Genetic algorithm (GA) is used to find the TTFLC boundary values of membership functions (MF) and weights of control rules. In addition, artificial neural networks (ANN) modelled dynamic behaviour of PM is given. This ANN model is used to find the optimal TTFLC parameters by offline GA approach. The experimental results show that designed TTFLC successfully enables the PM speed track the given trajectory under various working conditions. The proposed approach is superior to PID controller. It also provides simple and easy design procedure for the PM speed control problem.     

Consumer complaints and accidents related to food packaging

This study investigated consumer complaints related to food packaging design and the occurrence of injuries associated with the opening of various types of containers. Each study participant (245) took a 15 min fact‐to‐face interview and was asked attitudinal questions about 10 different categories of packaging including cans, glass and plastic bottles and jars, and paper‐based composite packages. The subjects were also asked whether they had been injured while opening these packaging types. The survey showed that cans which needed a tool for opening were most difficult to enter. In some cases the tool was the source of injury. The respondents were also most concerned about deformation, spillage and product wastage associated with these types of containers. This included brick‐type composite packages without a peelable seal over the pour spout. A large percentage of the respondents felt that more information was needed on the various methods of opening packages in general. Glass bottles and jars were most likely to be used for storage of products after they were emptied of their original contents. The results of this study could be used by manufacturers to assist them in the design and development of packaging with a lower potential to cause accidents and injuries. Copyright © 2010 John Wiley & Sons, Ltd.     

Erratum to “The effect of particle size on the erosion of a ductile material at the low particle size limit” [Wear 233–235 (1999) 727–736]

The intrinsic particle size dependence of erosion rate was investigated in the absence of aerodynamic effects. An apparatus was designed to impact small particles on metallic substrates at normal incidence in vacuum. Two types of target materials, Cu–30% Zn and pure Ti, were impacted with SiO₂ particles with average diameters of 2, 5 and 25 μm. The velocity of impact was 12 m/s. Damage processes induced by single particles were characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). This latter technique allowed for the measurement of impact profiles, both of the cut surfaces and the associated displaced material pile-ups. The impacts produced were, in many cases, asymmetrical, and the asymmetries appeared to be related to the orientation of the impacted surface. The appearance of the damage was essentially the same for all three sizes of the erodent, and for two different substrate materials having different crystal structures.     

Biodiesel production from inedible animal tallow and an experimental investigation of its use as alternative fuel in a direct injection diesel engine

In this study, a substitute fuel for diesel engines was produced from inedible animal tallow and its usability was investigated as pure biodiesel and its blends with petroleum diesel fuel in a diesel engine. Tallow methyl ester as biodiesel fuel was prepared by base-catalyzed transesterification of the fat with methanol in the presence of NaOH as catalyst. Fuel properties of methyl ester, diesel fuel and blends of them (5%, 20% and 50% by volume) were determined. Viscosity and density of fatty acid methyl ester have been found to meet ASTM D6751 and EN 14214 specifications. Viscosity and density of tallow methyl esters are found to be very close to that of diesel. The calorific value of biodiesel is found to be slightly lower than that of diesel. An experimental study was carried out in order to investigate of its usability as alternative fuel of tallow methyl ester in a direct injection diesel engine. It was observed that the addition of biodiesel to the diesel fuel decreases the effective efficiency of engine and increases the specific fuel consumption. This is due to the lower heating value of biodiesel compared to diesel fuel. However, the effective engine power was comparable by biodiesel compared with diesel fuel. Emissions of carbon monoxide (CO), oxides of nitrogen (NO_x), sulphur dioxide (SO₂) and smoke opacity were reduced around 15%, 38.5%, 72.7% and 56.8%, respectively, in case of tallow methyl esters (B100) compared to diesel fuel. Besides, the lowest CO, NO_x emissions and the highest exhaust temperature were obtained for B20 among all other fuels. The reductions in exhaust emissions made tallow methyl esters and its blends, especially B20 a suitable alternative fuel for diesel and thus could help in controlling air pollution. Based on this study, animal tallow methyl esters and its blends with petroleum diesel fuel can be used a substitute for diesel in direct injection diesel engines without any engine modification.     

Novel homo- and hetero-nuclear copper(II) complexes of tetradentate Schiff bases: synthesis, characterization, solvent-extraction and catalase-like activity studies

Twelve homo- and hetero-nuclear copper(II) complexes of tetradentate Schiff base ligands containing N(4) donor sets have been prepared by employing several steps. The characterization and nature of bonding of the complexes have been deduced from elemental analysis, FT-IR, molar conductivity, magnetic moment measurements and thermal analysis. The three Schiff base ligands were further identified using (1)H and (13)C NMR spectra. All copper(II) complexes are 1:2 electrolytes as shown by their molar conductivities (Lambda(M)) in DMF and paramagnetic. The subnormal magnetic moment values of the di- and tri-nuclear complexes explained by a very strong anti-ferromagnetic interaction. The extraction ability of the ligands has been examined by the liquid-liquid extraction of selected transition metal (Mn(2+), Co(2+), Ni(2+), Cu(2+), Zn(2+), Pb(2+), Cd(2+), Hg(2+)) cations. The ligands show strong binding ability toward copper(II) ion. Furthermore the homo- and hetero-nuclear copper(II) complexes were each tested for their ability to catalyse the disproportionation of hydrogen peroxide in the presence of the added base imidazole.     

Effect of packing on void morphology in resin transfer molded E‐glass/epoxy composites

Effects of applying a packing pressure on void content, void morphology, and void spatial distribution were investigated for resin transfer molding (RTM) E‐glass/epoxy composites. Packing pressures of zero and 570 kPa were respectively applied to center‐gated composites containing 17.5% randomly oriented, E‐glass fiber preform. Radial samples of these disk‐shaped composites were utilized to evaluate voidage via microscopic image analysis. Two adjacent surfaces were cut from each molded disk in order to evaluate void presence from both through‐the‐thickness and planar views. The packed composite was found to contain almost 92% less void content than the unpacked composite. While void fractions of 2.2 and 2.6% were measured, respectively, from the through‐the‐thickness and planar surfaces of the unpacked composite, only 0.2% void content was observed in the packed composite from both surfaces. Digital images obtained from through‐the‐thickness surface showed that average void size dropped from 59.3 μm in the unpacked composite to 31.7 μm in the packed composite. A similar reduction in average void size from 66.7 to 41.1 μm was observed from the planar surfaces. Circular voids were found to experience higher removal rates at 99%, followed by cylindrical and elliptical voids at 83 and 81%, respectively; while irregular voids show slightly lower void removal rates at 67%. Void proximity to fiber bundles was also observed to affect void reduction as voids located inside fiber tows experience lower void reduction rates. Along the radial direction of the molded disks, removal of voids with different proximities to fibers seems to depend on their arrangement at the end of the filling stage. These findings are believed to ascertain packing as an effective void removal method for RTM and similar liquid composite molding processes. POLYM. COMPOS., 26:614–627, 2005. © 2005 Society of Plastics Engineers     

Formation of α/β-Si3N4 nanoparticles by carbothermal reduction and nitridation of geopolymers

Silicon nitride (Si₃N₄) particles with various α/β-Si₃N₄ ratios were fabricated from geopolymer (GP)-carbon compositions (M₂O·Al₂O₃·4.5SiO₂·12H₂O+18C), where M is an alkali ion (Na⁺, K⁺ and Cs⁺). They were made by carbothermal reduction and nitridation at 1400°, 1500°, and 1600°C for 2 hours under flowing nitrogen. Characterization of carbothermally reacted GP-carbon compositions was based on XRD, SEM-EDS, HRTEM, and selected area electron diffraction analyses. Depending on the alkaline composition of GP, the carbon content and the reaction temperature, a compositionally variable α/β-Si₃N₄ or SiAlON was achieved. Crystallization of the GPs gradually increased by heat treatment over 1400°C with corresponding weight loss. It was found that NaGP, KGP, and CsGP crystallized into a major phase of α-Si₃N₄, β-Si₃N₄, and SiAlON, respectively. Prolonged heating at 1600°C led to an increase in the α/β-Si₃N₄ ratio in NaGP due to the formation of aluminum nitride, while it led to a decrease in α/β-Si₃N₄ ratio in KGP. In the case of CsGP, SiAlON replaced the pollucite which mainly formed at lower temperatures. Transmission electron microscopy revealed that the needle-like particles were of ~0.5 µm in size and consisting of α/β-Si₃N₄ mixtures.     

Synthesis and characterization of poly(1,3‐thiazol‐2‐yl‐carbomoyl) methyl methacrylate: Its metal complexes and antimicrobial activity studies

Poly(1,3‐thiazol‐2‐yl‐carbomoyl) methyl methacrylate [poly(TCMMA)] is prepared in dimethyl sulfoxide using 2,2′‐azobisisobutyronitrile as an initiator at 60°C. Poly(TCMMA) is characterized by IR and ¹H‐NMR spectroscopic techniques. Cadmium(II), copper(II), and nickel(II) chelates of poly(TCMMA) were synthesized. An elemental analysis of the polychelates suggests a metal/ligand ratio of 1:2. The polychelates are further characterized by IR and magnetic susceptibility measurements. The thermal properties of the polymer and metal chelates are also discussed. The molecular weights of the poly(TCMMA) are determined by the gel permeation chromatography technique. The antimicrobial activities of the polymer and metal chelates are tested against Staphylococcus aureus COWAN I (bacteria), Escherichia coli ATCC 25922 (bacteria), Listeria monocytogenes SCOTTA (bacteria), Bacillus subtilis LMG (bacteria), Enterobacter aeroginosa CCM 2531 (bacteria), Klebsiela pneumania FMCS (bacteria), Candida albicans CCM 314 (Mayo yeast), and Saccharamyces cerevisiae UGA 102 (Mayo yeast). © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3244–3251, 2003