A novel shielding material prepared from solid waste containing lead for gamma ray

Human beings are continuously exposed to cosmogenic radiation and its products in the atmosphere from naturally occurring radioactive materials (NORM) within Earth, their bodies, houses and foods. Especially, for the radiation protection environments where high ionizing radiation levels appear should be shielded. Generally, different materials are used for the radiation shielding in different areas and for different situations. In this study, a novel shielding material produced by a metallurgical solid waste containing lead was analyzed as shielding material for gamma radiation. The photon total mass attenuation coefficients (μ/ρ) were measured and calculated using WinXCom computer code for the novel shielding material, concrete and lead. Theoretical and experimental values of total mass attenuation coefficient of the each studied sample were compared. Consequently, a new shielding material prepared from the solid waste containing lead could be preferred for buildings as shielding materials against gamma radiation.     

Fatty acid composition of six Centaurea species growing in Konya, Turkey

In this study, fatty acid compositions of six Centaurea species growing in the Konya region were determined. The fatty acid composition of Centaurea balsamita, Centaurea calolepis, Centaurea carduiformis subsp. carduiformis, Centaurea cariensis subsp. maculiceps, C. cariensis subsp. microlepis and Centaurea iberica were analysed. Four species of these six Centaurea are endemic to Turkey. The endemic Centaurea species are C. calolepis, C. carduiformis subsp. carduiformis, C. cariensis subsp. maculiceps and C. cariensis subsp. microlepis. Generally, C 18:2 ω6 linoleic acid, C 16:0 palmitic acid, C 18:3 ω3 linolenic acid and C 18:1 oleic acid were found to be the major fatty acids in all species. Polyunsaturated fatty acids (PUFAs) were found in higher amounts than saturated fatty acids and monounsaturated fatty acids in all species. PUFAs were determined at 55.10%, 50.25%, 51.41%, 41.02%, 46.18% and 58.80% in C. balsamita, C. calolepis, C. carduiformis subsp. carduiformis, C. cariensis subsp. maculiceps, C. cariensis subsp. microlepis and C. iberica, respectively.     

(Liquid + liquid) equilibria of (heptane,or hexane,or cyclohexane + toluene + 1,3-dimethyl-2-imidazolidinone) ternary systems at T = 298.15 K

Experimental (liquid + liquid) equilibrium data for the mixtures of (heptane, or hexane, or cyclohexane + toluene + 1,3-dimethyl-2-imidazolidinone) were determined at T = 298.15 K and P = 101.3 kPa. The solubility (binodal) curves and tie-line end compositions are reported for the related mixtures and presented as complete phase diagrams. Distribution coefficients and separation factors were evaluated for the immiscibility region. The reliability of the experimental tie-line results was verified by using the Othmer–Tobias correlation. The experimental tie-line data were correlated by UNIQUAC model, which gave satisfactory representation for the systems. It was observed that the separation of toluene from cyclohexane is easier to achieve than from heptane and hexane.     

Synthesis and characterization of new polyphenols derived from o-dianisidine: The effect of substituent on solubility, thermal stability, and electrical conductivity, optical and electrochemical properties

In this study, we proposed to synthesize soluble polyphenol derivatives containing azomethine bond. For this reason, o-dianisidine was chosen to synthesize Schiff base monomers due to containing dimethoxy groups. Four phenolic Schiff bases were synthesized by condensation reaction of o-dianisidine with salicylaldehyde (2-HBADIAN), 4-hydroxybenzaldehyde (4-HBADIAN), vanillin (MHBADIAN) and 3-ethoxy-4-hydroxybenzaldehyde (EHBADIAN). These monomers were converted to their polyphenol derivatives via oxidative polycondensation reaction (OP). The structures of the obtained compounds were confirmed by FT-IR, UV-vis, ¹H NMR and ¹³C NMR techniques. Progressing of OP was also followed by a time-controlled spectrum mode of a UV-vis spectrophotometer. The molecular weight distribution parameters of the synthesized polyphenols were determined by the size exclusion chromatography (SEC). The synthesized compounds were also characterized by solubility tests, TG-DTA and DSC. Cyclic voltammetry (CV) measurements were carried out and HOMO-LUMO energy levels and electrochemical band gaps () were calculated. Additionally, optical band gaps (E_g) were determined by using UV-vis spectra of the materials. Electrical conductivities of both doped and undoped states of the synthesized materials were measured by four-point probe technique using a Keithley 2400 electrometer showing that P-2-HBADIAN has approximately 130 times higher electrical conductivity than the others. Also, it was stressed that the synthesized polyphenols are semiconductors which have a potential for electronic and optoelectronic applications, with fairly low band gaps.     

Fluorescent chemosensor for Ag(I) based on amplified fluorescence quenching of a new phthalocyanine bearing derivative of benzofuran

A fluorescent chemosensor for Ag(I) as a new family of peripherally functionalized zinc-phthalocyanine, 2(3),9(10),16(17),23(24)-tetrakis-{6-(-benzofuran-2-carboxylate)-hexylthio} phthalocyaninatozinc(II) {Zn[Pc(β-S(CH₂)₆OCOBz-furan)₄], (ZnPcBzF), (3), which was derivated from 6-(3,4-dicyanophenylthio)-hexyl–2-benzofuranate (BzF), (2), has been synthesized and fully characterized by elemental analysis, FT-IR, ¹H and ¹³C NMR, MS (ESI and Maldi-TOF). An optical silver ion (Ag(I)) sensor based on the fluorescence quenching of benzofuran moiety and ZnPc core was developed. Both absorbance and fluorescence spectra of ZnPcBzF, (3) exhibit distinct changes in visible region in response to treatment with Ag(I) ion in solution. Such properties make compound ZnPcBzF, (3) intriguing candidates for incorporation into the transducer layer in optically based chemical sensors.     

Synthesis and liquid crystal properties of phthalocyanine bearing a star polytetrahydrofuran moiety

A new polymeric ligand, 6-(3,4-dicyanophenylthio)-hexyl-2-polytetrahydrofuranacetate (2) and its liquid crystalline polymeric phthalocyanine, 2,9,16,23-tetrakis-{6-(polytetrahydrofuran-2-carboxylate)-hexylthio-phthalocyaninatocobalt(II) (3), {Co[Pc(S-C₆H₁₃OCO-poly-THF)₄]}(CoPcLC) have been synthesized. The ligand and the phthalocyanine, bearing polytetrahydrofuran moieties (poly-THF), were characterized using elemental analysis, FTIR, ¹H and ¹³C NMR, and UV–Vis techniques. CoPcLC (3) promotes a greater interaction between the mesogens, resulting in solution aggregations together with a red-shift in the Q-band in the presence of the soft Ag⁺ ion. The dielectric anisotropy and phase transition temperature values of CoPcLC doped with 4-cyano-4′-n-pentylbiphenyl (5CB) were found to be 7.17 and 40.5 °C, respectively. The dielectrical anisotropy behaviour of the liquid crystals changes from the positive to the negative type. The current–voltage characteristics of the liquid crystals show a non-linear behaviour.     

The first and efficient synthesis of some of the polyhalogenated benzobarrelenes: unusual formation of a benzosemibullvalene derivative

New polyhalogenated benzobarrelenes were synthesized in good yields. The bromination reaction of benzobarrelenes at high temperature gives non-rearranged products. Dehydrobromination of the formed products with t-BuOK yielded the desired polyhalogenated benzobarrelenes. The elimination reaction of cyclopropanoid dibromide with a base unusually resulted in the formation of a benzosemibullvalene derivative.     

Design of a single layer micro-perforated sound absorber by finite element analysis

Micro-perforated sound absorbers with sub-millimeter size holes can provide high absorption coefficients. This paper presents results of work on the development of an effective single layer micro-perforated sound absorber from the commercial composite material Parabeam^® with micro diameter holes drilled on one side. Parabeam^® is used as a structural material made from a fabric woven out of a E-glass yarn and consists of two decklayers bonded together by vertical piles in a sandwich structure with piles (thick fibers) woven into the decklayers. The paper includes, the analytical model developed for prediction of absorption coefficients, finite element solution using commercial software MSC.ACTRAN and experimental results obtained from impedance tube measurements. A simple optimization is performed based on the developed models to obtain an efficient absorber configuration. It has been anticipated that several different and interesting applications can be deduced by combining structural and sound absorption properties of this new micro-perforated absorber.     

Strong optical limiting property of a ball-type supramolecular zinc-phthalocyanine in polymer-phthalocyanine composite film

The nonlinear absorption and optical limiting (OL) performance of a supramolecular hexa-phthalocyaninato-hexazinc (II) with hexylthio substituents in solution and in the solid-state have been described using the open-aperture Z-scan technique. The measurements were performed using collimated 4 ns pulses generated from a frequency-doubled Nd:YAG laser at 532 nm wavelength. The results indicated that OL performance of the investigated compound in the polymeric film is much better compared to properties in solution. With the excellent combination of OL parameters the investigated compound in the solid-state is a candidate for the use as optical limiter.