Interval type-2 fuzzy inverse controller design in nonlinear IMC structure

In the recent years it has been demonstrated that type-2 fuzzy logic systems are more effective in modeling and control of complex nonlinear systems compared to type-1 fuzzy logic systems. An inverse controller based on type-2 fuzzy model can be proposed since inverse model controllers provide an efficient way to control nonlinear processes. Even though various fuzzy inversion methods have been devised for type-1 fuzzy logic systems up to now, there does not exist any method for type-2 fuzzy logic systems. In this study, a systematic method has been proposed to form the inverse of the interval type-2 Takagi-Sugeno fuzzy model based on a pure analytical method. The calculation of inverse model is done based on simple manipulations of the antecedent and consequence parts of the fuzzy model. Moreover, the type-2 fuzzy model and its inverse as the primary controller are embedded into a nonlinear internal model control structure to provide an effective and robust control performance. Finally, the proposed control scheme has been implemented on an experimental pH neutralization process where the beneficial sides are shown clearly.     

Chemical Profile and Biological Activities of Two Edible Plants: Chemical Investigation and Quantitative Analysis Using Liquid Chromatography Tandem Mass Spectrometry and Gas Chromatography Mass Spectrometry

The objectives of this study were to define the phenolic and fatty acid profiles, anticholinesterase, antioxidant, antimicrobial activities, and total phenolic-flavonoid contents of Lycopsis orientalis and Tragopogon latifolius var. angustifolius which have been used as food source and food supplement in Anatolia and have never been examined before. Rosmarinic and quinic acids (21.11 and 11.46 mg g^–1 extract, respectively) were found to be the most abundant constituents in L. orientalis and T. latifolius var. angustifolius among the studied 27 compounds by liquid chromatography tandem mass spectrometry. In the fatty acid compositions of L. orientalis and T. latifolius var. angustifolius that were determined by gas chromatography mass spectrometry, oleic (29.1%) and palmitic (28.7%) acids were identified as the major components, respectively. The high antioxidant activity of the methanol extract of L. orientalis shows parallelism to its rosmarinic acid content. Besides, this extract showed medium anticholinesterase activity. The results of the present study proves that the L. orientalis might also be used as a food source due to its high phenolic acid content and strong antioxidant property.     

Evaluation of the bond strength of different bonding agents to porcelain and metal alloy

This study was carried out with the purpose of testing the bond strength of different bonding agents bonded to different substrates.Substrates consisted of cylindrical specimens of three different materials: porcelain, metal, and a porcelain–metal combination. Specimens were all 10 mm in diameter and 4 mm thick. Surfaces to be bonded were air-abraded with Al₂O₃ and cleaned ultrasonically in distilled water for 10 min. After the preparation of the surface was complete, three different bonding agents were applied to the central region of the substrates. Composite resin of a 3.5 mm diameter and 2 mm thick was applied. All specimens were thermocycled between 5 and 55 °C for 200 cycles with a 30-s dwell time. After thermocycling, specimens were stored at 37 °C in distilled water for an additional 7 days before being subjected to a shear load. Shear testing was conducted Hounsfield test machine.The univariate analysis of variance and the Duncan multiple comparison test were used for statistical assessment. It was found that both type of bonding agents and of substrate led to statistically significant differences in bond strength (p<0.01).It was found that the highest bond strength was produced by Clearfil and on pure alloy substrate (33.36 MPa) and the lowest bond strength in Single Bond and porcelain–alloy substrate (4.25 MPa).     

The effect of borax pentahydrate addition to urea formaldehyde on the mechanical characteristics and free formaldehyde content of plywood

In this study, the effects of borax pentahydrate addition to urea formaldehyde (UF) on the bonding characteristics and free formaldehyde content have been studied. Experiments related to the bending strength, withdrawal shear strength and free formaldehyde content have been conducted on the three-layered beech and poplar plywood which are prepared by the addition of borax pentahydrate into their adhesive mixtures in certain amounts. Addition of borax pentahydrate into the adhesive mixture did not statistically affect the bending strength and withdrawal shear strength of the plywood but did reduce the free formaldehyde content.     

Type-2 fuzzy model based controller design for neutralization processes

In this study, an inverse controller based on a type-2 fuzzy model control design strategy is introduced and this main controller is embedded within an internal model control structure. Then, the overall proposed control structure is implemented in a pH neutralization experimental setup. The inverse fuzzy control signal generation is handled as an optimization problem and solved at each sampling time in an online manner. Although, inverse fuzzy model controllers may produce perfect control in perfect model match case and/or non-existence of disturbances, this open loop control would not be sufficient in the case of modeling mismatches or disturbances. Therefore, an internal model control structure is proposed to compensate these errors in order to overcome this deficiency where the basic controller is an inverse type-2 fuzzy model. This feature improves the closed-loop performance to disturbance rejection as shown through the real-time control of the pH neutralization process. Experimental results demonstrate the superiority of the inverse type-2 fuzzy model controller structure compared to the inverse type-1 fuzzy model controller and conventional control structures.     

New simple transistor realizations of second- generation voltage conveyor

In this paper, two new complementary metal oxide semiconductor (CMOS) realizations for second-generation voltage conveyor (VCII) are presented. The first proposed VCII has a very simple structure employing only six transistors. The second proposed VCII employs 11 transistors, and none of the transistors at both proposed circuits suffer from the body effect. Small-signal analysis, parasitic elements, and input-referred noise of the proposed VCIIs are given. Moreover, a new active element called voltage controlled second-generation voltage conveyor (VC-VCII) is proposed as dual element of current controlled second-generation current conveyor (CCCII) active element. Its parasitic resistance at the Y terminal can be controlled electronically. Two presented CMOS structures of VCII are worked as VC-VCII with slight modification. Proposed circuits are simulated in Cadence Analog environment using TSMC 0.18-μm process parameters with ±0.9-V supply voltages. Both CMOS structures occupy a small chip area of 276.8 and 271 μm², respectively. The bandwidth of the current follower stage of the proposed VCIIs is found as 794 MHz, whereas the bandwidth of the voltage follower stage for the first and second proposed VCIIs is found as 2.57 and 1.92 GHz, respectively. As an application example, voltage-mode first-order low-pass filter has been given with its tunable gain by using VC-VCII.     

Determination of polyphenolic constituents and biological activities of bark extracts from different Pinus species

BACKGROUND: The most common commercially available pine bark extract is Pycnogenol^®, a standardised extract of Pinus maritima, which has been reported to have cardiovascular benefits and enhance microcirculation. The present study was conducted to determine the chemical composition of four pine bark extracts, assess their biological activities and to compare the results with Pycnogenol^®. RESULTS: The Pinus species were analysed by LC and LC‐MS; extracts of P. brutia and P. nigra showed higher levels of phenolic constituents compared to P. sylvestris and P. pinea. In particular, P. brutia contained extremely high concentrations of taxifolin (18.5%). The highest radical scavenging activities were attained with P. pinea (88.6%), P. nigra (87.2%) and P. brutia (86.4%) bark extracts. Additionally, anticarcinogenic effects of the extracts and their kinetics were determined in four cell lines including human prostate (PC‐3, DU 145, LNCaP) and breast adenocarcinoma (MCF7) by the MTT assay. Cell viability was reduced to 40% by extracts of P. pinea, and P. sylvestris in PC‐3 cells showing a similar effect like the positive control, CPT‐11. CONCLUSION: Pinus species other than P. maritima definitively possess high biological activities, and therefore present a huge potential to be utilised in the food and the pharmaceutical industries. Copyright © 2009 Society of Chemical Industry     

Effect of surface treatment on electrical conductivity of carbon black filled conductive polymer composites

Two different types of surface modifiers, 3‐aminopropyltriethoxysilane and formamide, were applied to carbon black (CB) particles to lower electrical resistivity of polymer composites prepared by treated CB. Two different matrices, low‐density polyethylene and nylon 6, were chosen to compound with surface modified CB. Surface energy of CB was increased by adding amine or amide functional groups during surface treatment of CB. According to electron spectroscopy for chemical analysis (ESCA), chemical modification in surface chemistry of CB was obtained with the chemicals used for the treatment due to the nitrogen atoms in their structures, which may act as dopant atom. As a result of this, electrical resistivity of composites prepared by treated CB decreased. In addition, there was not any significant change in tensile strength and tensile modulus of the composites with the surface treatment. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Effect of composite preparation techniques on electrical and mechanical properties and morphology of nylon 6 based conductive polymer composites

Nylon 6/carbon black conductive composites were prepared using two different methods, masterbatch dilution and melt mixing. Their effect on the size and distribution of carbon black agglomerates in the matrix was studied in terms of electrical and mechanical properties and morphology. The electrical resistivity of composites prepared by both methods decreased with increasing filler composition. The electrical resistivity of the diluted masterbatch composites and the melt mixed composites was reduced from the resistivity of pure nylon 6, 10¹⁵ “ohm, cm”, to 10⁷ “ohm, cm” at 1 and 6 wt % of carbon black, respectively. As the filler content increased, elongation at break and impact strength decreased, but tensile modulus increased. Masterbatch dilution method provided smaller carbon black clusters in composites compared to melt mixing method. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2520–2526, 2006     

Cross‐Coupled Ratio Control Structure

Abstract

In this paper, a cross‐coupled ratio control structure with two blend stations has been proposed. The main feature of the proposed structure is to give a good ratio performance for both set‐point changes and load disturbances that might occur in any one of the two loops. A simple tuning procedure for the inner controllers of the two loops and an easy design methodology for the blend stations have been proposed in order to avoid any significant tuning and design effort for the implementer. The proposed structure is realized on a microcontroller based system. This cross‐coupled ratio control structure that has been embedded into the microcontroller is then used to maintain the prescribed ratio “a” of the two processes, namely heat transfer process trainer (PT 326‐Feedback) and process control simulator (PCS 327‐Feedback). The same two processes are run under another alternative ratio control structure and the results are compared with each other.