KARAÇALI (Paliurus spina-christi Mill.) ve HÜNNAP (Zizyphus jujuba Mill.) TOHUMLARININ ÇİMLENDİRİLMESİ ÜZERİNE GA3, ÇITLATMA VE EKİM ZAMANININ ETKİLERİ

Bu çalışmada, karaçalı (Paliurus spina-christi Mill.) ve hünnap (Zizyphus jujuba Mill.) türlerinde bazı tohum özellikleri ile GA3, çıtlatma ve uygun ekim zamanının çimlenme oranına etkileri çalışılmıştır. Hünnap tohumları, 1 Ekim-1 Nisan tarihleri arasında 14 farklı ekim tarihi ve iki farklı ön işlem kullanılarak ekilmiştir. Karaçalı tohumları ise, 1 Ekim-1 Nisan tarihleri arasında 13 farklı tarihte ekilmiştir. Sonuç olarak; Karaçalı türünde kapsüllerdeki ortalama tohum sayısı 2.72 adettir. Tohumların 1000 tane ağırlığı ise ortalama 21.2 g’dır. Hünnap tohumlarının 1000 tane ağırlığı ortalama 308 g’dır. Hünnapta yüksek çimlenme oranı elde edebilmek için, tohumlar 400 ppm GA3’te 24 saat bekletilip ekim ayında ekilmeli ya da tohumlar çıtlatıldıktan sonra 12 saat 100 ppm GA3 çözeltisinde tutulup aralık – ocak aylarında ekim gerçekleştirilmelidir. Ekim- kasım aylarında ekilmesi daha uygun çıkan karaçalı tohumları ise, ekilmeden önce mutlaka, 100 ppm GA3 çözeltisinde 12 saat süreyle önişleme alınmalıdır. Anahtar kelimeler: Karaçalı, Hünnap, Çimlendirme, GA3, Çıtlatma, Ekim zaman

Dielectric relaxation dynamics of high-temperature piezoelectric polyimide copolymers

Polyimide co-polymers have been prepared based on different diamines as co-monomers: a diamine without CN groups and a novel synthesized diamine with two CN groups prepared by polycondensation reaction followed by thermal cyclodehydration. Dielectric spectroscopy measurements were performed and the dielectric complex function, ac conductivity and electric modulus of the co-polymers were investigated as a function of CN group content in the frequency range from 0.1 Hz to 107 Hz at temperatures from 25 to 260 °C. For all samples and temperatures above 150ºC, the dielectric constant increases with increasing temperature due to increaseing conductivity. The α-relaxation is just detected for the sample without CN groups, being this relaxation overlapped by the electrical conductivity contributions in the remaining samples. For the copolymer samples and the polymer with CN groups an important Maxwell-Wagner-Sillars contribution is detected. The mechanisms responsible for the dielectric relaxation, conduction process and electric modulus response have been discussed as a function of the CN groups content present in the samples.This work was supported by FEDER through the COMPETE Program and by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Project PESTC/FIS/UI607/2011 and grants SFRH/BD/ 62507/2009 (A.C.L.) SFRH/BD/68499/2010 (C.M.C.). The authors also thank funding from “Matepro – Optimizing Materials and Processes”, ref. NORTE-07-0124-FEDER-000037”, co-funded by the “Programa Operacional Regional do Norte” (ON.2 – O Novo Norte), under the “Quadro de Referência Estratégico Nacional” (QREN), through the “Fundo Europeu de Desenvolvimento Regional” (FEDER). RSS acknowledge the support of the Spanish Ministry of Economy and Competitiveness through the project MAT2012-38359-C03-01 (including the FEDER financial support). Authors also thank the Basque Country Government for financial support (ACTIMAT project, ETORTEK Program, IE13-380, and Ayudas para Grupos de Investigación del Sistema Universitario Vasco Program, IT718-13)

Liquid-liquid extraction of transition metal cations by diazo coupling calix[4]arene derivatives

The selective liquid-liquid extraction of various alkaline, alkaline-earth and transition metal cations from the aqueous phase to the organic phase was carried out by using diazo coupling calix[4]arenes [p-(4-n-butyl-phenylazo)calix[4]arene(L1), p-(4-phenylazophenylazo)calix[4]arene(L2), p-(4-acetamlidazo)calix[4]arene(L3), p-(N′-2-thiazol-2-ylsulphanylazo)calix[4]arene(L4) and p-(2-thiazolazo)calix[4]arene(L5)] and the phenol derivatives [2-(5-bromo-2-pyridylazo)-5-diethylaminophenol(L6) and (2-chloro-4-nitrophenylazo)-5-secbutyl-2-phenol(L7)]. It was found that compounds L1-L6 showed some selectivity towards Ag+, Hg+ and Hg2+, while extractability of all cations was observed with compound L2 containing double diazo groups

Comparative studies on the solvent extraction of transition metal cations by calixarene, phenol and ester derivatives.

The ionophore solvent extraction of various alkali metal and transition metal cations from the aqueous phase to the organic phase was carried out by using diazo-coupling calix[n]arenes [p-(4-phenylazophenylazo)calix[4]arene (L1) and p-phenylazocalix[6]arene (L2)], phenol derivatives [2,6-dimethyl-3-phenylazophenol (L3), 2-(5-bromo-2-pyridylazo)-5-diethylamino phenol (L4), 2-chloro-4-nitro(phenylazo)-5-sec-butyl-2-phenol (L5) and 2-chloro-4-nitro(phenylazo)-5-tert-butyl-2-phenol (L6)], and ester derivatives [quinoline-8-benzoate (L7), phenyl-1,4-dibenzoate (L8), p-tolyltiobenzoate (L9)]. It was found that, all the compounds (L1-L9) examined showed selectivity for transition metal cations such as Ag+, Hg+ Hg2+, and poor efficiency for alkali metal cations (Na+ and K+). The best extraction efficiency was obtained with L1 and L4

Internal charge transfer based Hg-sensing Azocalix[4]arene Mono anthracenate derivatives

The present study describes the synthesis and characterization of mono anthracenate derivatives of azocalix[4]arene. The azocalix[4]arene anthracenates (6a-e) were performed by the esterification of the 2-bromoethyl antracenate (5) and azocalix[4]arene (3a-e) in dry acetonitrile. The prepared compounds were characterized by using the 1H NMR, IR, DTA/DTG techniques and elemental analysis. They were examined to observe their capabilities of recognizing various cations including K+, Ag+, Hg+, Hg2+, Co2+, Ni2+, Cu2+, Pb2+, Cr3+ and Al3+ with UV-vis spectroscopy. It was found that the extraction mechanisms of metal cations are highly effective with the azo (NN) groups and adjacent anthracenate electron density. The synthesized azocalix[4]arene ligands (6a-e) were obtained fluorescence emission with Na+, K+, Sr2+, Ag+, Hg2+, Co2+, Cu2+, Pb2+, Ba2+, Ca2+ and Mg2+ metal ions at a wavelength of 367 nm. © 2015 Elsevier B.V. All rights reserved

First-principles study of the structural, elastic, electronic, optical, and vibrational properties of intermetallic Pd2Ga

WOS: 000301341400059The structural, elastic, electronic, optical, and vibrational properties of the orthorhombic Pd2Ga compound are investigated using the norm-conserving pseudopotentials within the local density approximation in the frame of density functional theory. The calculated lattice parameters have been compared with the experimental values and found to be in good agreement with these results. The second-order elastic constants and the other relevant quantities, such as the Young's modulus, shear modulus, Poisson's ratio, anisotropy factor, sound velocity, and Debye temperature, have been calculated. It is shown that this compound is mechanically stable after analysing the calculated elastic constants. Furthermore, the real and imaginary parts of the dielectric function and the optical constants, such as the optical dielectric constant and the effective number of electrons per unit cell, are calculated and presented. The phonon dispersion curves are derived using the direct method. The present results demonstrate that this compound is dynamically stable

Transition metal cations extraction by ester and ketone derivatives of chromogenic azocalix[4]arenes.

The molecule of azocalix[n]arene is a macrocyclic used effectively in the complexation of the heavy metal pollutants (like silver and mercury). In this work, our main aim is to prepare new chromogenic azocalix[n]arene molecules to elaborate an extractant with high extractant selectivity for metal ions able to detect this type of pollutant. The solvent extraction properties of four acetyls, four methyl ketones and four benzoyls derivatives from azocalix[4]arenes which were prepared by linking 4-ethyl, 4-n-butyl, 4-acetamid anilin and 2-aminothiazol to calix[4]arene through a diazo-coupling reaction, the alkaline earth (Sr2+) and the transition (Ag+, Hg2+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+, Cr3+) metal cations have been determined by extraction studies with metal picrates. Both ketones are better extractants than esters, and show a strong preference for Ag+, while Cu2+ and Cr3+ are the most extracted cation with the esters. Both acetyl and benzoyl esters are good carriers for Ag+ and Hg2+