Daily peak ozone forecast in Istanbul

In this study, we attempt to develop an ozone forecast model using two different approaches. The first approach is to use a multiple linear regression method and the second is to use a feed-forward artificial neural network. Models are developed for the ozone period of April through to September of the years 2002 and 2003 and verified for May to August 2004. In both models, 19 predictors are used. Calculated agreement indices (AI) for the model development period are 0.82 for the linear regression model and 0.88 for the artificial neural network model. On the other hand, AI values decrease to 0.53 and 0.64 for the validation period. Poor performance of the models in the validation phase might be due to the different maximum daily ozone averages of these two periods. While the average of maximum ozone values is 61.1 μg m^?3 in the model development phase, it is 42.2 μg m^?3 in the model validation phase.     

Polyindene/organo‐montmorillonite conducting nanocomposites. I. Synthesis,characterization, and electrokinetic properties

In this study, Na‐montmorillonite was organically modified with cetyltrimethylammoniumbromide (CTAB) and intercalated with in‐situ polymerized indene. Polyindene(PIn)/Organo‐MMT nanocomposites were obtained with three different compositions and coded as: K1: [PIn(94.5%)/O‐MMT(5.5%)], K2: [PIn(92.8%)/O‐MMT(7.2%)], and K3: [PIn(87.9%)/O‐MMT(12.1%)]. These nanocomposites were subjected to full characterization with various techniques. Electrokinetic studies were conducted to reveal the zeta (ζ)‐potential characteristics of the nanocomposites. ζ‐potentials of the materials were observed to decrease with increasing O‐MMT content. The cationic (CTAB) and anionic (sodium dodecylsulfate) surfactants were shifted the ζ‐potentials of the colloidal dispersions to more positive and more negative regions, respectively whereas nonionic surfactant (Triton X‐100) caused almost no change. The pH and temperature were observed to shift the ζ‐potential values of the nanocomposites to more negative and slightly more positive regions, respectively. With the addition of mono (NaCl), di (BaCl₂) and three (AlCl₃) valent salts, the ζ‐potential of the nanocomposites were shifted to more negative, more positive, and much more positive regions, respectively. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Enhancement of hybrid sol–gel coating and industrial application on polished porcelain stoneware tiles and investigation of the performance

The aim of this study was to improve stain resistance and cleanability of polished porcelain tiles by sealing the micro-pores on the tile surface with hybrid sol–gel solution. For this purpose, solutions of a hybrid system based on sol–gel technology were prepared. The obtained solution were applied to polished unglazed tiles and subsequently spread with soft tissue thereon. To achieve complete sealing, both organic and inorganic particles of different sizes were mixed with obtained sol–gel hybrid systems. Coated surfaces were investigated by means of a scanning electron microscope. The stain resistance and the cleanability of the tile surface were tested according to ISO-10545-2014 standard. It has been shown that prepared sealing material permanently prevents formation of stains such as olive oil, green staining paste, iodine solution on the surface of polished porcelain tiles. The remains of stains on the surface can easily be removed from it with a cleaning agent.     

Production of oil-based binder by RAFT polymerization technique

In this study, air-blown linseed oil was styrenated by reversible addition–fragmentation chain transfer polymerization (RAFT). For this purpose, hydroperoxide groups were formed in the structure of linseed oil by blowing air through it. The oxidized oil was used as a macroinitiator in the styrenation process by RAFT technique using phenacyl morpholine dithiocarbamate (PMDC) as a RAFT agent. The obtained samples were characterized by GPC and FT-IR measurements. The effects of various parameters, such as the amount of PMDC, the number of peroxide groups, and the reaction time were investigated on polydispersity and molecular weight. For comparison, a copolymer sample was also prepared in the absence of PMDC. The film properties of all the samples were determined according to the related standards and compared. The sample obtained by the RAFT technique exhibited better film properties and a relatively narrow polydispersity, showing that the RAFT technique provides good control over the polymerization system in this study.     

pH-dependent swelling of hydrogels containing highly branched polyamine macromonomers

We examine the pH-dependent swelling of end-linked hydrogels containing high concentrations of amine-functional macromonomers. Gels are formed by end-linking of epoxide-terminated, linear poly(ethylene glycol) (PEG) to either amine-terminated poly(amidoamine) (PAMAM) dendrimers or highly branched poly(ethyleneimine) (PEI). After extraction in neutral water, the hydrogels are swollen in aqueous solutions of HCl or NH₄OH to vary the external pH. Equilibrium volume swelling ratios (Q_s) pass through a maximum value (Q_max) at an external pH denoted as pH^∗ which is approximately 4-5 for the gels studied. The swelling behavior is modeled using Donnan equilibrium theory to describe the ion swelling pressure, with the Flory-Rehner phantom network expression representing the elastic and mixing contributions to the free energy. The model accurately predicts the maximum in swelling near pH = 4-5, but overestimates Q_max for several of the gels due to neglecting the finite extensibility of the short linear PEG chains.     

Gafchromic film as a fast visual indicator of radiation exposure of first responders

Three types of Gafchromic films have been studied to investigate their potential for use as a visually readable dosemeter for persons acting as first responders in connection with radiological or nuclear emergencies. The two most sensitive film types show a pronounced variation in sensitivity by photon energy and are therefore not suitable for use in cases of unknown exposures. The third film type tested (RTQA2), which is intended for quality control in radiation therapy has a sensitivity that is independent of the radiation quality, and is therefore considered as the most optimal for visual reading in situ. Tests carried out on a group of 10 human observers showed that absorbed doses down to 40 mGy can be detected by the eye. Read by a portable densitometer, qualitative absorbed dose estimates down to 9 mGy can be achieved. The colour change is obtained instantaneously, giving first responders immediate information about the presence of beta-, gamma- and X-ray radiation.     

Novel approach with polyfluorene/polydisulfide copolymer binder for high-capacity silicon anode in lithium-ion batteries

In this study, as a novel design with the collaboration of a fluorene and sulfide-based copolymer for Li-ion battery application is presented. Polyfluorene-co-polydisulfide is prepared with desired functional groups to yield a conductivity and good adhesion. These critical and important features are performed by preparing polymers with proper functional groups. The preparation process is accomplished via Suzuki coupling process under Pd catalyst by combining separately synthesized 4,4′-dibromodiphenyl disulfide in combination with 9,9-dioctylfluorene-2,7-bis(trimethylborate). The fully obtained capacity of the silicon particles, that is, at C/10 with the capacity of 1250 mAh g⁻¹ after the 500th cycle, approves the good performance by preserving capacity stability till 600th cycles. The designed and synthesized polymer binder with different functionalities and carbon nanotube additive show better characteristics such as conductivity, high polarity, and binding adhesion. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48303.     

A new species of Cassida Linnaeus, 1758, from Turkey (Chrysomelidae: cassidinae)

A new species, Cassida alidagiense sp. nov., has been described from Kayseri province in Turkey. For the time being, the species is endemic to Turkey. Cassida alidagiense sp. nov., is related to Cassida linnavuorii Borowiec, 1986; Cassida brevis Weise, 1884; and Cassida bella Faldermann, 1837, from which it differs in the shape of the apex of cornu of the spermethaca, and it can be distinctively differentiated from these species based on color of under body and spermathecal characters especially. In addition, the paper presents ultrastructures observed by SEM of spermatheca of Cassida alidagiense sp. nov. from Turkey.     

Influence of the ER,CR:YSGG laser and different irrigation methods on push-out bond strength of fiber post

Er,Cr:YSGG lasers are currently being investigated for disinfecting the root canal treatment. The aim of this study was to compare the effects of various irrigation protocols on push-out bond strength of fiber posts. Fifty maxillary anterior teeth were divided into five groups (n = 10) according to the protocol that applied into the post space. Group-1: distilled water, Group-2: 5% NaOCl, Group-3: 2% CHX, Group-4: Er,Cr:YSGG laser (1.5 W, 20 Hz, 85 air, 75 water, 26.7 J/cm²), Group-5: Er,Cr:YSGG laser (1.25 W, 50 Hz, 34 air, 24 water, 12.7 J/cm²). Fiber posts were cemented with resin cement. The remaining part of the root, three slices were obtained from each specimen and push-out test was performed. One-way ANOVA and Duncan’s test at a 5% level of significance were used for the statistical analysis. Post space irradiation with Er,Cr:YSGG laser (1.5 W 20 Hz, 85 air, 75 water, 26.7 J/cm²) increases push-out bond strength of fiber post to root canal dentin. Further investigations are needed to establish and optimize ER,Cr:YSGG laser parameters to increase the push-out bond strength of fiber posts.     

Styrenation of air-blown linseed oil by nitroxide-mediated radical polymerization

Styrenation of air-blown linseed oil by a nitroxide-mediated radical polymerization (NMRP) technique is described. In this technique, air-blown linseed oil bearing hydroperoxide groups was used as a macroinitiator in NMRP of styrene in the presence of 2,2′,6,6′-tetramethylpiperidinyl-1-oxy (TEMPO). The effects of various parameters, such as the amount of TEMPO and hydroperoxide groups, were investigated in terms of molecular weight and polydispersity. For comparison, a copolymer sample of air-blown linseed oil with styrene was also prepared in the absence of TEMPO. The film properties of all samples were determined according to the related standards and were compared with respect to surface protection. Samples prepared by the NMRP technique exhibited relatively narrow polydispersity and better film properties compared to those of the samples obtained by the conventional method.