Quinoxaline derivatives as long wavelength photosensitizers in photoinitiated cationic polymerization of diaryliodonium salts

The present paper is focused on visible light initiated cationic polymerizations. Photoinitiated polymerization of representative vinyl ether and oxirane monomers using two quinoxaline derivatives; namely (2-(2,3-dihydrobenzo [b][1,4]dioxin-6-yl)-3-(2,3-dihydrobenzo[b]-[1,4]dioxin-7-yl)-5-(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)-8-(2,3-dihydrothieno[3,4-b][1,4]dioxin-7yl) quinoxaline) (DBQEd) and 2,3,5,8-tetra(thiophen-2-yl)quinoxaline (TTQ) are studied. Novel dyes based on the quinoxaline skeleton are employed as efficient photosensitizers in cationic photopolymerizations. Polymerizations were initiated at room temperature upon irradiation with long-wavelength UV and visible lights in the presence of diphenyliodonium hexafluorophosphate (Ph₂I⁺PF₆^?). The progress of the polymerizations was monitored by optical pyrometry (OP). Solar irradiation is also employed to carry out the cationic polymerization of a diepoxide monomer in the presence of air.     

The oxidative and lipolytic stability of Yayık butter produced from different species of mammals milk (cow,sheep, goat) yoghurt

Yay?k butter, made from yoghurt, is one of the traditional dairy products in Anatolia In this study, some properties of Yay?k butter produced from cow, sheep, and goat yoghurts have been observed during 30 days of storage at 4–5 °C. In this purpose yoghurts were produced from different species milks then these yoghurts were used as a raw material for production of Yay?k butters samples. On the first day of the storage, differences in pH of serum among the butter produced from different mammals were statistically significant. The highest value of lactic acid was measured in the sample of sheep butter (SB). The level of lactic acid in Yay?k butters was significantly different. Goat butter (GB) had weaker oxidative stability and significantly higher peroxide value than those of other samples. The highest accumulation of the free fatty acids has been detected in sample GB. All samples of Yay?k butter received almost the same score on the first day of the storage, but on day 30 some flavour defects in sample GB were noted by the panelists.     

Performance prediction of a proton exchange membrane fuel cell using the ANFIS model

In this study, the performance (current–voltage curve) prediction of a Proton Exchange Membrane Fuel Cell (PEMFC) is performed for different operational conditions using an Adaptive Neuro-Fuzzy Inference System (ANFIS). First, ANFIS is trained with a set of input and output data. The trained model is then tested with an independent set of experimental data. The trained and tested model is then used to predict the performance curve of the PEMFC under various operational conditions. The model shows very good agreement with the experimental data and this indicates that ANFIS is capable of predicting fuel cell performance (in terms of cell voltage) with a high accuracy in an easy, rapid and cost effective way for the case presented. Finally, the capabilities and the limitations of the model for the application in fuel cells have been discussed.     

Modeling educational usage of Facebook

The purpose of this study is to design a structural model explaining how users could utilize Facebook for educational purposes. In order to shed light on the educational usage of Facebook, in constructing the model, the relationship between users' Facebook adoption processes and their educational use of Facebook were included indirectly while the relationship between users' purposes in using Facebook and the educational usage of Facebook was included directly. In this study, data is collected from Facebook users with an online survey developed by the researchers. The study group consists of 606 Facebook users whose answers were examined by using a structural equation model. The analyses of the 11 observed and 3 latent variables provided by the model showed that 50% of educational usage of Facebook could be explained by user purposes along with the adoption processes of Facebook. It was also found that Facebook adoption processes could explain 86% of all user purposes. Finally, while Facebook adoption processes explained 45% of its educational usage, it could explain 50% of variance in educational usage of Facebook when the user purposes were added into the analyses.     

Determination of Critical Aggregation Concentration in the Poly-(vinylpyrrolidone)–Sodium Dodecyl Sulfate System by Capillary Electrophoresis

We introduce an alternative separation method, i.e., capillary electrophoresis to examine the polymer/surfactant interaction. The migration behavior of the poly-(vinylpyrrolidone)–sodium dodecyl sulfate (PVP–SDS) model system was screened under a high electrical field for seven different PVP initial concentrations. From the electrophoretic mobilities of formed polymer–surfactant species, the critical aggregation concentration (CAC) of SDS for PVP was determined. The CAC value in the present study was very well matched with the CAC values of this system reported by alternative methods. A strong interaction between polymer and SDS under CAC concentration was observed and the independence of CAC on polymer concentration was experimentally demonstrated.     

Multilevel statistical inference from functional near-infrared spectroscopy data during stroop interference

Functional near-infrared spectroscopy (fNIRS) is an emerging technique for monitoring the concentration changes of oxy- and deoxy-hemoglobin (oxy-Hb and deoxy-Hb) in the brain. An important consideration in fNIRS-based neuroimaging modality is to conduct group-level analysis from a set of time series measured from a group of subjects. We investigate the feasibility of multilevel statistical inference for fNIRS. As a case study, we search for hemodynamic activations in the prefrontal cortex during Stroop interference. Hierarchical general linear model (GLM) is used for making this multilevel analysis. Activation patterns both at the subject and group level are investigated on a comparative basis using various classical and Bayesian inference methods. All methods showed consistent left lateral prefrontal cortex activation for oxy-Hb during interference condition, while the effects were much less pronounced for deoxy-Hb. Our analysis showed that mixed effects or Bayesian models are more convenient for faithful analysis of fNIRS data. We arrived at two important conclusions. First, fNIRS has the capability to identify activations at the group level, and second, the mixed effects or Bayesian model is the appropriate mechanism to pass from subject to group-level inference.     

Effect of combined application of plant extract and vacuum packaged treatment on the quality of hot smoked rainbow trout

The effect of plant extract (bay leaf, rosemary, black cumin seed and lemon oil) treatment on the shelf life of vacuum-packaged fish was studied. Hot smoked rainbow trout was treated with 1 % plant extracts, and their shelf lives were compared with those of control (only vacuum packaged) samples. Samples were stored at 2 °C and sensory evaluation as well as chemical and microbiological analyses were conducted weekly. The control group was spoiled after four weeks of storage. In contrast the addition of plant extracts decreased microbiological activity. The results obtained from this study showed that the shelf life of hot smoked trout stored in cold storage (+2 °C), as determined by overall acceptability of all data, was 6 weeks for rosemary, black cumin seed, and lemon oil treatment plus vacuum packaged fish and 7 weeks for bay leaf oil treatment plus vacuum packaged smoked fish.     

The effect of methyl-tri-n-butylammonium methylsulfate and graphite nanoplates on production of antistatic acrylic polymer

Methyl-tri-n-butylammonium methylsulfate (BIL) was incorporated into acrylic resin to improve antistatic property of acrylic polymer (AP). In order to avoid reduction in the mechanical properties of acrylic film and to reach higher electrical conductivity values, the combination of graphite nanoplates (Gr) and BIL was used. The effects of incorporation of BIL and Gr into AP on UV-blocking properties and UV transmittance data of acrylic films were measured. After 120 days, AP containing 5 wt% BIL and 0.01 wt% Gr, and AP+15 wt% BIL exhibited antistatic property. While BIL incorporation into acrylic resin deteriorated the mechanical properties, 0.01 wt% Gr incorporation increased the tensile strength by 83%.     

An efficient soft demapper for APSK signals using extreme learning machine

Neural Computing and Applications - In this paper we introduce an efficient soft demapping method for amplitude phase shift keying (APSK) constellations using extreme learning machine (ELM). The...     

Synthesis and characterization of metal ion-imprinted polymers

In this study, ion-imprinted polymeric materials from an aqueous solution were prepared to remove metal ions \((\hbox {M}^{2+})\) like \(\hbox {Ni}^{2+}\), \(\hbox {Co}^{2+}\), etc. To prepare ion-imprinted polymers (IIPs), acrylic acid derivatives (XA) like acrylamide (AAm), methacrylic acid and itaconic acid were chosen as monomers. Metal ions formed binary chelate complexes with the help of 8-hydroxyquinoline (8-HQ). The solution containing functional monomers and the binary complex were polymerized with the help of various cross-linkers [ethylene glycol dimethylacrylate (EGDMA) or trimethylpropane trimethacrylate (TMPTMA)] and the target ion was removed from this polymer through an applicable method to produce IIPs. Furthermore, the control polymers (CPs) were synthesized through the same method without using metal ion. Characterization of the polymeric materials was investigated through spectroscopic (FTIR/ATR), thermal (TGA, DSC) and surface (SEM and XRD) analyses. Functional monomers, cross-linkers and the target ion’s species were changed during preparation of IIPs to observe their effect on imprinting of the target ion. Adsorption of the target ion to the prepared IIPs and the factors affecting the adsorption like concentration, pH, temperature, mass, etc. were studied.