Wavelet based Neuro-Detector for low frequencies of vibration signals in electric motors

This study presents a Wavelet based Neuro-Detector approach employed to detect the aging indications of an electric motor. Analysis of the aging indications, which can be seen in the low frequency region, is performed using vibration signals. More specifically, two vibration signals are observed for healthy and faulty (aged) cases which are measured from the same electric motor. Multi Resolution Wavelet Analysis (MRWA) is applied in order to obtain low and high frequency bands of the vibration signals. Thus for detecting the aging properties in the spectra, the Power Spectral Density (PSD) of the subband for the healthy case is used to train an Auto Associative Neural Network (AANN). The PSD amplitudes, which are computed for the faulty case, are applied to input nodes of the trained network for the re-calling process of AANN. Consequently, the simulation results show that some spectral properties defined in low frequency region are determined through the error response of AANN. Hence, some specific frequencies of the bearing damage related to the aging process are detected and identified.     

Some Tauberian theorems for regularly generated sequences

In this paper, we establish some Tauberian theorems for the Abel summability method in terms of regularly generated sequences which generalizes some results obtained in Çanak and Totur [?. Çanak, Ü. Totur, A note on Tauberian theorems for regularly generated sequences, Tamkang J. Math. 39 (2) (2008) 187-191].     

Antimicrobial Effect of Ozone on Cariogenic Microorganisms In Vitro

The aim of this study was to examine the antibacterial effect of ozone on cariogenic microorganisms. Streptococcus salivarius, Streptococcus mutans, Lactobacillus acidophilus, Lactobacillus casei and Actinomyces viscosus were used to test the antimicrobial activity of ozone. The microorganisms were exposed to power levels 2, 3, or 4 of an ozone device for 20, 40, 60, or 120 s. CFU numbers of bacteria were counted after the ozone application; as a result, the number of bacterial cells was decreased. The bacterial cells were also evaluated with a fluorescence microscope. This analysis revealed that some bacterial cells were killed instantaneously in ozone. The electron microscopic analysis showed no difference in surface morphology between bacteria to which ozone had been applied and those to which it had not.     

Aluminum diboride synthesis from elemental powders by mechanical alloying and annealing

In this study, AlB₂ powders were synthesized by using a combined method of mechanical alloying (MA) and annealing of elemental aluminum (Al) and boron (B) powders. Milling was performed in a planetary ball-mill (Fritsch? Pulverisette 7 Premium Line) up to 15 h under argon (Ar) atmosphere. Annealing process was carried out in a tube furnace at 650 °C for 6 h under Ar atmosphere. The effects of MA durations on the annealing process and AlB₂ formation were investigated. The conversion of Al and B powders to AlB₂ starts after only MA for 3 h or after MA for 1 h and subsequent annealing. A slight formation of AlB₁₂ occurs at 242 °C for as-blended powders and it shifts to about 272 °C for MA’d powders. Al–B powder blends MA’d for 9 h and annealed have AlB₂ particles in size between 35 and 75 nm in the presence of Al₁₃Fe₄, Fe₃B and Fe₂B contaminations.     

Electrochemical synthesis and characterization of poly(9-benzylfluorene)

In this study, we report the electrochemical polymerization of 9-benzylfluorene (9-BF) in acetonitrile solution. The characterization of the resulting poly(9-BF) film obtained on the working electrode has been performed by using attenuated total reflectance infrared spectroscopy. Besides electrochemical properties, the optical and photoluminescent properties of film were also investigated in detail by means of UV–Vis spectroscopy and fluorescence spectroscopy. Fluorescent spectral studies indicate that polymer film in solid state emits blue-green light at around 470/520 nm under irradiation of UV light. In addition, scanning tunneling microscopy was used to investigate the morphology of poly(9-BF) film. The morphological results also reveal that the surface of single crystalline gold electrode is completely covered with the polymer film.     

Synthesis and photopolymerizations of new hydroxyl-containing dimethacrylate crosslinkers

Two new hydroxyl-containing di(meth)acrylate monomers were synthesized from the reaction of methyl α-chloromethylacrylate (MCMA) and of ethyl α-chloromethylacrylate (ECMA) with glycerol. The monomers were obtained as mixtures of two isomers in different ratios and in combination with the analogous trimethacrylate monomers. Each monomer was isolated by column chromatography. The photopolymerization of these isomer mixtures and the trimethacrylate monomers was investigated individually by photodifferential scanning calorimetry (photoDSC) at room temperature using 2,2′-dimethoxy-2-phenyl-acetophenone (DMPA) as a photoinitiator. The effect of hydrogen bonding on the rates of polymerizations and conversions was examined. The results obtained for the synthesized monomers were compared to the values obtained for commercial monomers. It was observed that the hydroxyl-containing dimethacrylates polymerize much faster and to considerably higher conversion than the trimethacrylate monomers. The maximum rates of polymerization of the hydroxyl-containing monomers were higher than that of the hexanediol dimethacrylate (HDDMA), comparable to glycerol dimethacrylate and lower than hexanediol diacrylate (HDDA) and 3-(acryloyloxy)-2-hydroxypropyl methacrylate (AHM).     

High-Temperature Sliding Wear Testing of Cathodic Arc Physical Vapor Deposition AlTiN- and AlTiON-Coated Hot Work Tool Steels

Thin hard coatings provide the much needed protection for steel thixoforming tools that must resist wear at high temperatures. The wear resistance of AlTiN- and AlTiON-coated hot work tool steel was investigated at 1023 K (750 °C), measured to be the cavity surface temperature shortly after the steel slurry was forced into the thixoforming die. The wear tests were repeated in exactly the same fashion with uncoated tool steel samples to identify the impact of AlTiN and AlTiON coatings on the high-temperature wear performance of X32CrMoV33 tool steel. The nature, the thickness, and the adherence of the oxide scales impact the tribological behavior. The poor adherence and limited ductility of ferrous oxides promote the failure of the oxide scale impairing the resistance to wear of the hot work tool steel at elevated temperatures. The substantial softening in the X32CrMoV33 hot work tool steel is also critical in the wear volume loss it suffers. AlTiN and AlTiON coatings, on the other hand, form a stable and protective oxide surface layer at high temperatures and therefore provide an enhanced resistance to oxidation. The latter is relatively more resistant to oxidation and is thus the better of the two coatings tested in the present work.     

Effects of different polymerization protocols on the degree of conversion of two dual‐cured core buildup composites polymerized by light‐emitting diode and halogen light‐curing units

The aim of study was to investigate the effects of various curing protocols with quartz–tungsten halogen (QTH) or light‐emitting diode (LED) light‐curing units on the degree of conversion (% DC) of two dual‐cured core buildup resin composites. Two dual‐cured core buildup resin composites, Clearfil Dc Core Automix (CLF) and Grandio Core Dc (GR), were selected. Specimens were exposed to the polymerization protocols as follows: there was immediate photoactivation or photoactivation delayed by 2 or 5 min by a QTH or LED source, and one group was allowed to chemically polymerize and served as a control (n = 6). The % DC of the specimens was determined with attenuated total reflectance–Fourier transform infrared spectroscopy. The GR samples polymerized with QTH for the 5‐min‐delayed photoactivation had higher % DC values than those self‐cured, and the Clearfil Dc Core Automix (CLF) samples with immediate or delayed curing protocols with halogen yielded higher % DC values than the samples that were chemically polymerized. The comparison of the two resin composites polymerized with halogen showed a higher % DC for CLF than for GR in the 2‐min‐delayed photoactivation. On the other hand, when they were cured with LED, the % DC values of GR significantly increased after the 2‐min‐delayed photoactivation. In light of the results, it might be stated that CLF polymerized with QTH, could be the better option. GR provided adequate chemical polymerization; therefore, it might be useful in areas in which light curing is not possible. Clinicians should consider the polymerization characteristics of dual‐cured resin composites. The use of different composites may require the modification of the application procedures recommended by the manufacturer. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40560.     

Physico-chemical and sensory properties of chips produced using different lupin (Lupinus albus L.) flour formulations and cooking methods

Development of novel snack foods is an important area of research, and different ingredients are being tested to develop and process new formulations. In this study, lupin chips prepared using different formulations (hulled lupin, whole lupin, wheat and corn flours) were cooked using baking and frying, and changes in the sensory and colour parameters, acrylamide contents, fat absorption, peroxide number and p-anisidine values of the final products were studied. Lupin flour significantly changed p-anisidine value of chips. Addition of lupin flour and cooking methods affected the colour, fat absorption and peroxide values. Significant differences in chemical properties of chips made from whole and hulled lupin flours were also observed. Acrylamide was not detected in all the formulations studied. The lupin chips have increased brightness (L*), no acrylamides, reduced peroxide and p-anisidine values and acceptable sensory quality; hence, this ingredient is recommendable for use in snack foods.