Makale 2000-2009 yılları

Permanent URI for this collection

https://kurumsalarsiv.tenmak.gov.tr/handle/20.500.12878/269

Browse

Now showing 1 - 20 of 20

Graft copolymerization of pu membranes with acrylic acid and crotonic acid using benzoyl peroxide initiator
(John Wiley & Sons, Inc., 2001-01-28) Babayiğit, Doğan; Pulat, Mehlika; TAEK-RSGD
To improve water wettability of polyurethane (PU) ,graft copolymerization with acrylic acid (AA) and crotonic acid (CA) was performed using benzoyl peroxide (BO) initiator. The grafting reaction was carried out by placing the membranes in aqueous solutions of AA and CA at constant temperatures. Variations of graft yield with time ,temperature, initiator and monomer concentrations were investigated.The optimum temperature, polymerization time, monomer and initiator concentrations for AA were found to be 70 C; 3h; 1.5 M; 5.0 x 10-2 M and for CA 70 C; 1h; 1.5 M; 4.0 x 10(-2) M , respectively. The grafting membranes were characterized by FTIR spectroscopy and scanning electron microscopy (SEM) analysis and the effect of grafting on equilibrium water content (EWC) of PU membranes was obtained by swelling measurements.
Surface modification of pu membranes by graft copolymerization with acrylamide and itaconic acid monomers
(Elsevier B.V., 2001-10) Babayiğit, Doğan; Pulat, Mehlika; TAEK-RSGD
To improve water wettability of polyurethane (PU), graft copolymerization of acrylamide (AAm) and itaconic acid (IA) was performed using benzoyl peroxide (BO) initiator. The grafting reaction was carried out by placing the membranes in aqueous solutions of AAm and IA at constant temperatures. Variations of graft yield with time, temperature, initiator and monomer concentrations were investigated. The optimum temperature, polymerization time, initiator and monomer concentrations for AAm were found to be 80°C, 2 h, 4.0x10(-2) M and 1.5 M and for IA, 80°C, 1 h, 4.0x10(-2) M and 1.5 M, respectively. The membranes were characterized by FTIR spectroscopy and scanning electron microscopy (SEM) analysis and the effect of grafting on equilibrium water content (EWC) of PU membranes was obtained by swelling measurements.
Effects of temperature and moisture stress during elongation and branching on development and yield of safflower
(Centro de Investigación y Desarrollo Agrario (Córdoba, Argentina); Consejo Superior de Investigaciones Científicas (Spain). Instituto de Agricultura Sostenible., 2002) Uslu, Nevzat; Tutluer, İhsan; Kunter, Burak; Sağel, Zafer; Peşkircioğlu, Hayrettin; Kantoğlu, K. Yaprak; TAEK-ANTHAM
Although safflower is considered a drought resistant crop, irregular distribution of precipitation and limited rain are the main risk factors for growing this crop in fields under dryland agriculture. This study presents the effects of water shortage and high temperature during stem elongation and branching on development and yield of safflower under non-irrigated conditions in Ankara (Turkey). Three years of results showed that plant height, number of heads per plant, head diameter, and yield were reduced drastically (from 74.4 to 48.2 cm; from 10.2 to 4.1 heads/plant; from 2.3 to 1.9 cm and from 218.9 to 48.4 kg/da, respectively) when the crop was subjected to limited rains. Consequently, supplementary irrigation must be applied during the specific stages of plant i.e. elongation and/or preflowering for ensuring the development of safflower under Ankara conditions.
Occupational exposure to ionising radiation in the region of Anatolia, Turkey for the period 1995-1999
(Oxford, 2004) Gündüz, Hüseyin; Zeyrek, C. Tuğrul; Aksu, Levent; Işak, Solmaz; 0000-0001-6744-7841; TAEK-ANAEM
For this study, the individual annual dose information on classified workers who occupational exposure due to extended radiation sources in Anatolia region of Turkey was assessed and analysed by the Ankara Nuclear Research and Training Centre dosimetry service (ANAEM) at the Turkish Atomic Energy Authority (TAEA) for the years 1995-1999. The monitored radiation workers are divided into three main work sectors: conventional industry (8.24%), medicine (90.20%) and research-education (1.56%). The average annual dose for all workers in each particular sector was 0.14 mSv , 0.38 mSv and 0.08 mSv, respectively, in 1995 to 1999. This paper contains the detailed analysis of occupational exposure. The statistical analysis provided includes the mean annual dose, the collective dose, distributions of the dose over the different sectors and the number of workers that have exceed any the established dose levels.
The synthesis, crystal structure and spectroscopic properties of a dinuclear μ–pyrazolato–N,N’–bridged dinickel(II) complex of 1,3-bis(salicylideneamino)propan–2–ol
(De Gruyter, 2004) Zeyrek, C. Tuğrul; Elmalı, Ayhan; Elerman, Y.; 0000-0001-6744-7841; TAEK-ANAEM
The title compound [Ni2(L)(3,5 prz)], prz = pyrazolate with the formally pentadentate ligand L = 1,3-bis(salicylideneamino)propan-2-olate, was synthesized and identified using elemental analysis and IR spectroscopy. It crystallizes in the monoclinic space group P21/c with cell parameters a = 29.873(4), b = 11.131(2), c = 13.166(3) Å , β = 107.770(10)°, V = 4169.0(13) Å3, Z = 4, Dcal = 1.618 Mg/m3. The nickel ions are bridged by the alkoxo group of the ligand and the N atoms of the μ-pyrazolate group. Each nickel(II) ion is coordinated by two N atoms and two O atoms, forming a square with trans-N2O2 geometry. The Ni···Ni distance and the Ni−O−Ni angle are 3.371(1) Å and 126.4(1)°, respectively.
A modelling study for the health risk posed by nuclear power plant in Bulgaria at different parts of Turkey
(Parlar Research and Technology, 2004) Ünver, Özge; Tuncel, Gürdal; Kozloduy; TAEK-NGD
In this study, following a severe accident in Kozloduy nuclear power plant in Bulgaria, how Turkey will be affected has been investigated. The atmospheric dispersion model used is Hybrid Single Particle Lagrangian Integrated Transport (HySPLIT) model.For the simplicity, the release of only I-131 and Cs-137 for the worst-case accident scenario was modeled by HySPLIT for each day of the arbitrarily selected year 2000 to find the worst day of deposition, which was seen to result from the release beginning on April 7th 2000 and accumulated at the end of the 15-day simulation. Afterthat release of all fission products was modeled for the worst deposited day. Radiation dose at different receptors, which are 12 grids throughout Turkey, was calculated via inhalation, ingestion and external radiation pathways. Delayed health risk, fatal cancer, non-fatal cancer and hereditary risks, were investigated for the receptor points. The mostly affected part of Turkey fatal cancer is 0.121%. The same approach was applied to investigate the health risk of the proposed nuclear power plant at Akkuyu, Turkey. In this case, it was seen that the worst deposited day was resulted from the release beginning on 21st of February 2000 and accumulated at the end of the 15-day simulation. The worst affected part was found as the area between Kayseri, Niğde and Nevşehir with the total effective dose commitment of 0.108 Sievert and the individual risk of suffering from fatal cancer 0.54%. KEY WORDS: Kozloduy, Turkey, accident, HySPLIT,dose,risk.
Sarımsakta (Allium sativum L.) radyasyonla mutasyon ıslahına yönelik olarak ''etkili mutasyon dozunun'' belirlenmesi
(Yalova Atatürk Bahçe Kültürleri Araştırma Enstitüsü, 2004) Kantoğlu, K. Yaprak; Beşirli, Gülay; Yanmaz, Ruhsar; Kunter, Burak; TAEK-ANTHAM
Radyasyonla mutasyon ıslahı çalısmalarına temel olusturmak üzere yürütülen bu çalısmada, fiziksel mutagen olarak sarımsak dislerine Cs137 kaynagı ile 0, 5, 10, 15, 20, 25, ve 30 Gy dozlarında ısınlama yapılmıstır. Isınlama sonrası 60. günde, her doz için dikilen 50'ser adet diste farklı ısın dozlarının çimlenme ve sürgün gelisimleri üzerine olan etkileri incelenerek "Etkili Mutasyon Dozu" (ED50) lineer regresyon analizleriyle hesaplanmıstır. Buna göre 4.455 Gy’lik doz, Tasköprü sarımsagı için etkili mutasyon dozu olarak belirlenmistir.
Kavunda (Cucumis Melo L.) farklı bitki parçalarının in vitro organ oluşumuna ortamın şeker ve pH düzeyinin etkisi
(Alata Bahçe Kültürleri Araştırma Enstitüsü, 2004-06) Kantoğlu, K. Yaprak; Yanmaz, Ruhsar; Yazar, Ezgi; Alper, Aslı; TAEK-ANTHAM
Araştırmada, in vitro mutasyon ıslahına yönelik çalışmalara temel olması için; Yuva kavun çeşidine ait in vitro bitkilerden alınan kotiledon ve yapraklı hipokotil parçalarının MS besin ortamında sürgün oluşturma kapasiteleri üzerine farklı şeker (%15, 20 ve 25) konsantrasyonlarının ve pH seviyelerinin (5.6, 5.7, 5.8) etkileri incelenmiştir. Araştırma sonucunda, kotiledon parçalarından sadece kallus oluşumu sağlanırken, yapraklı hipokotil parçalarından kallus oluşumu ile birlikte sürgün oluşumu meydana gelmiştir. En yüksek oranda ve kaliteli sürgün oluşumu, bitki parçası başına ortalama 4,98 adet sürgün olacak şekilde %15 şeker içeren ve pH'sı 5,6 olan olan MS besin ortamında elde edilmiştir.
A theoretical analysis of the explanation of the significant differences in antiferromagnetic interactions between homologous μ-alkoxo and acetate bridged dicopper(II) complexes: ab initio and semi-empirical calculations
(Elsevier, 2004-07) Zeyrek, C. Tuğrul; Elmalı, Ayhan; Elerman, Y.; 0000-0001-6744-7841; TAEK-ANAEM
A magnetostructural classification of dimmers, containing the Cu (μ-alkoxo) Cu core, based on data obtained from X-ray diffraction analysis reported in the literature has been performed. In these complexes, the local geometry around the copper ions is generally a square planar and each copper ion is surrounded by one N atom and three O atoms. The influence of the overlap interactions between the bridging ligands and the metal (Cu) d orbitals on the super-exchange coupling constant has been studied by means of ab initio Restricted Hatree–Fock molecular orbital calculations. The interaction between the magnetic d orbitals and highest occupied molecular orbitals of the acetate oxygens has been investigated in homologous μ-acetato-bridged dicopper(II) complexes which have significantly different −2J values (the energy separation between the spin-triplet and spin-singlet states). In order to determine the nature of the fronter orbitals, Extended Hückel molecular Orbital calculations are also reported. Ab initio restricted Hartree–Fock calculations have shown that the acetato bridge and the alkoxide bridge contribute to the magnetic interaction countercomplementarily to reduce antiferromagnetic interaction.
Occupational exposure to ionising radiation with thermoluminescence dosimetry system in Turkey, in 2003
(Oxford, 2005) Zeyrek, C. Tuğrul; Gündüz, Hüseyin; 0000-0001-6744-7841; TAEK-ANAEM
The individual annual dose information on classified workers who are occupationally exposed to extended radiation sources by using thermoluminescence dosimetry system, in Turkey was assessed and analyzed by the Ankara Nuclear Research and Training Centre (ANAEM) dosimetry service at the Turkish Atomic Energy Authority (TAEK) for the year 2003. A total of total 3721 persons were monitored with TLD and the data presented in this report was obtained by using TLD technology in 2003. The annual mean effective doses received from external radiation in the different fields of activity and the distributions of the annual effective dose by dose intervals are presented. The collective annual dose by field of activity is estimated and the contribution to the total annual collective dose is determined.
Crystal structure and magnetic exchange interaction in a binuclear copper(II) schiff base complex with a bridging m-phenylenediamine ligand
(De Gruyter, 2005) Zeyrek, C. Tuğrul; Elmalı, Ayhan; Elerman, Y.; Svoboda, I.; 0000-0001-6744-7841; TAEK-ANAEM
Condensation of 2-hydroxy-3-methoxybenzaldehyde with m-phenylenediamine (1,3-diaminobenzene) (m-pda) gives the ligand [N,N′-bis(2-hydroxy-3-methoxybenzylidene)-1,3-diaminobenzene] which reacts with cupric acetate to give the complex [Cu2(L-m-pda)2]·2H2O, [L = 2-hydroxy-3- methoxybenzaldehyde)]. The molecular structure of the complex [Cu2(L-m-pda)2]·2H2O has been determined by single-crystal X-ray analysis. (C44H40Cu2N4O8)·2H2O, triclinic, space group P1̄. Two [Cu(L-m-pda)] fragments, related by an inversion center, are connected by m-phenylene groups to form a binuclear unit. The coordination geometry around each copper(II) can be described as a distorted tetrahedron formed by the N2O2 donor set of the Schiff base ligands. The intramolecular Cu···Cu separation is 7.401(6) Å. The magnetic susceptibility of the complex in the 5 - 301 K temperature range can be rationalized by the parameters J = −0.4 cm−1 and g = 2.17. This indicates a weak intramolecular antiferromagnetic interaction. Extended Hückel molecular orbital (EHMO) calculations have been performed in order to gain insight into the molecular orbitals that participate in the super-exchange pathway.
Prompt gamma neutron activation analysis of boron in samples with A(241) Am-Be neutron source
(Springer Link, 2005-01) Turhan, Şeref; Yücel, Haluk; Demirbaş, Ahmet; TAEK-ANAEM
A prompt gamma neutron activation analysis (PGAA) set-up installed at ANRTC has been used to analyze boron in samples. It consists of a 22.6% REGe detector and a 740 GBq 241Am-Be neutron source moderated with water and paraffin. At the sample irradiation position, thermal neutron fluence rate measured was 2.36x10(4) n.m(-2).s(-1) and the corresponding Cd-ratio was 22 for gold monitor. The absolute detection efficiency in the range of 120-1500 keV was determined using (152)Eu standard solution. The sensitivity and detection limit for standard boric acid samples has been determined and also the boron content in boric acid prepared from Turkish borate ores is measured to be 15.91 +-0.46% wt. by this PGAA set-up.
Magnetic characterization, synthesis and crystal structure of a heterodinuclear CuIIGdIII Schiff base complex bridged by the two phenolic oxygen atoms
(Elsevier, 2005-04) Zeyrek, C. Tuğrul; Elmalı, Ayhan; Elerman, Y.; 0000-0001-6744-7841; TAEK-ANAEM
A novel heterodinuclear complex formed by the reaction of gadolinium nitrate with Schiff base complex of copper(II) has been synthesized and characterized. Preparation, crystal structure and magnetic properties of the heterodinuclear complex, LCu(Me2CO)Gd(NO3)3, (L=(N,N′-bis(2,3-dihydroxybenzylidene)-1,3-diaminopropane) are reported. The complex is consisting of a deca-coordinated GdIII ion which is bridged to four coordinated CuII via both phenolate oxygen atoms of the L Schiff base ligand. The average Cu⋯Gd separation is 3.475(2) Å. There is also one non-coordinating acetone molecule in the crystal structure. The magnetic susceptibility of the complex was measured over the range 4.5–350 K and the observed data were successfully simulated by the equation based on the spin-Hamiltonian operator H=−JSCu·SGd. The values of the intrachain interaction parameters have been deduced from the magnetic data: exchange integral J(Cu–Gd)=7.3 cm−1, gCu=2.17, gGd=2.09. This indicates a weak ferromagnetic spin exchange interaction between CuII and GdIII ions. The nature of the magnetic super-exchange interaction of the title compound is compared with similar CuIIGdIII heterodinuclear complexes.
Iron(III) induced imidazolidine ring hydrolysis of binucleating schiff base ligand: synthesis, crystal structures, spectroscopic properties and conformational study of a new μ-bis(tetradentate) schiff base and its mononuclear iron(III) complex
(De Gruyter, 2005-05) Zeyrek, C. Tuğrul; Elmalı, Ayhan; Elerman, Y.; 0000-0001-6744-7841; TAEK-ANAEM
The μ-bis(tetradentate) ligand, [C27H26Cl3N4O4], H3L′, 1,3-bis[N-(5-chloro-2-hydroxybenzylidene)- 2-aminoethyl]-2-(5-chloro-2-hydroxyphenyl)imidazolidine and its mononuclear iron(III) complex, [Fe(L)](ClO4), L = N, N′-bis(5-chloro-2-hydroxybenzylidene)-triethylenetetramine have been synthesized and their crystal structures determined. Minimum energy conformations of the ligand were calculated (MOPAC, AM1) as a function of two torsion angles and the results compared with optimized crystal structure. The ligand (H3L′) reacts with Fe(ClO4)2 · 6H2O in aqueous methanol to form the mononuclear [Fe(L)](ClO4) complex with the imidazolidine ring cleaved by hydrolysis. The complex has an N4O2 donor atom set forming a distorted octahedral coordination geometry around the metal atom as established from a crystal structure determination. The terminal oxygen donor atoms occupy cis positions, and the remaining four nitrogen atoms (two cis amine and two trans imine) complete the coordination sphere.
EPR and optical absorption studies of VO2+ doped KH2PO4 and KH3C4O8·2H2O single crystals
(Verlag der Zeitschrift fur Naturforschung, 2006) Bıyık, Recep; Tapramaz, Recep; 0000-0001-7929-4395; TAEK-ÇNAEM
VO2+ doped potassium dihydrogen phosphate (KH2PO4) and potassium tetraoxalate (KH3C4O8 · 2H2O) single crystals and powders are examined by electron paramagnetic resonance and optical absorption spectroscopy. Angular variations of KH2PO4 and KH3C4O8 ·2H2O single crystals show four and two different VO2+ sites, respectively. The local symmetry of VO2+ complexes is nearly axial for both host crystals. The optical absorption spectra show three bands. Spin Hamiltonian parameters are measured and molecular orbital coefficients are calculated by correlating EPR and optical absorption data for the central vanadyl ion.
Effects of radiation on carbapenems : ESR identification and dosimetric features of gamma irradiated solid meropenem trihydrate
(Taylor and Francis Ltd., 2006) Tepe Çam, Semra; Polat, Mustafa; Korkmaz, Mustafa; TAEK-SANAEM
In the present work, effects of gamma radiation on solid meropenem trihydrate (MPT), which is the active ingredient of carbapenem antibiotics, were investigated by electron spin resonance (ESR)spectroscopy.Irradiated MPT presents an ESR spectrum consisting of many resonance peaks.Heights measured with respect to the spectrum baseline of these resonance peaks were used to explore the evolutions of the radicalic species responsible for the experimental spectrum under different conditions. Variations of the denoted 11 peak heights with microwave power, sample temperature and applied radiation doses and decay of the involved radicalic species at room and at high temperatures were studied. On the basis of the results derived from these studies, a molecular model consisting of the presence of four different radicalic species was proposed, and spectroscopic parameters of these species were calculated through spectrum simulation calculations. The dosimetric potential of MPT was also explored and it was concluded that MPT presents the characteristics of normal and accidental dosimetric materials.
EPR spectra of Cu2+ in KH2PO4 single crystals
(Elsevier, 2007-03-18) Bıyık, Recep; Tapramaz, Recep; TAEK-ÇNAEM
Cu2+ doped single crystals of KH2PO4 were investigated using EPR technique at room temperature. The spectra of the complex contains large number of overlapping lines. Five sites are resolved and four of them are compatible with the tetragonal symmetry, and the fifth one belongs to an interstitial site. The results are discussed and compared with previous studies. Detailed investigation of the EPR spectra indicate that Cu2+ substitute with K+ ions. The principal values of the g and hyperfine tensors and the ground state wave function of Cu2+ ions are obtained.
Determination of gross α and β activities in Ankara airborne particulate samples in 2003–2004
(Akadémiai Kiadó, 2007-10) Akçay, Sultan; Tülümen, Şenay; Oymak, Simay; Kaya, Halil İbrahim; TAEK-SANAEM
Monitoring of atmospheric radionuclides is an important part of avoiding or eliminating the risk of diseases to the general public.1 Gross D and gross E activities results should be important in understanding the trends of atmospheric radioactivity and for the variation in time. Airborne particulate samples were collected monthly during the years 2003 and 2004. Radioactivities were determined using WPC 9550 D/E counting system. The arithmetic means of gross D/E activities were 2.02.10–3 and 2.85.10–3 Bq.m–3, respectively. The data obtained in this study provide a base line for evaluating possible future changes.
Radiation sensitivity and dosimetric features of sultamicillin tosylate : an electron spin resonance study
(Taylor & Francis, 2009) Tepe Çam, Semra; Polat, Mustafa; Korkmaz, Mustafa; TAEK-SANAEM
Particular interest now centers on the preparation of steril-unit dose preparations. When preparations are purified from microorganisms using classic sterilization techniques, serious degradations may occur especially in temperature sensitive drugs and drug active components. Sultamicillin is the tosylate salt of double ester of sulbactam plus ampicillin. Sultamicillin tosylate (SULT) has previously been shown to be clinically and bacteriologically effective in a variety of infections. The use of high-energy radiation such as gamma rays for the sterilization of pharmaceuticals offers considerable interest because of the clear advantages this process has, compared to other methods of sterilization. However, radiosensitivity of irradiated pharmaceutical is important in this respect. Thus, radiosensitivity of SULT and its potential use as a dosimetric material were investigated by Electron Spin Resonance (ESR) spectroscopy in the present work. Samples of SULT powder were irradiated at doses of 3, 6, 10 and 15 kGy and ESR spectra were recorded at room and at different temperatures. Variations of different spectroscopic parameters with irradiation dose, temperature, and storage time were evaluated using data derived from experimental ESR spectra which exhibited five different resonance peaks. Stabilities of the radiolytic intermediates at high temperatures were also investigated through annealing studies performed at 340, 345 and 350 K. Rapid decrease in the resonance peak heights above 325 K was considered as a manifestation of unstable character of the radiolytical intermediates at high temperature although they decayed relatively slowly at room temperature. Seven different mathematical functions have been tried to fit experimental dose-response data and a power function of the applied dose was found to describe best the dose-response data.
An EPR study on tea: Identification of paramagnetic species, effect of heat and sweeteners
(Elsevier, 2009-10) Bıyık, Recep; Tapramaz, Recep; 0000-0001-7929-4395; TAEK-ÇNAEM
Tea (Camellia Sinensis) is the most widely consumed beverage in the world, and is known to be having therapeutic, antioxidant and nutritional effects. Electron paramagnetic resonance (EPR) spectral studies made on the tea cultivated along the shore of Black Sea, Turkey, show Mn2+ and Fe3+ centers in green tea leaves and in black tea extract. Dry black tea flakes and dry extract show additional sharp line attributed to semiquinone radical. The origins of the paramagnetic species in black tea are defined and discussed. Effect of humidity and heat are investigated. It is observed that dry extract of black tea melts at 100 ◦C and the semiquinone radical lives up to 140 ◦C while Mn2+ sextet disappears just above 100 ◦C in tea extract. Natural and synthetics sweeteners have different effects on the paramagnetic centers. White sugar (sucrose) quenches the Mn2+ and semiquinone lines in black tea EPR spectrum, and glucose, fructose, lactose and maltose quench Fe3+ line while synthetic sweeteners acesulfam potassium, aspartame and sodium saccharine do not have any effect on paramagnetic species in tea.

Browse

Browsing Makale 2000-2009 yılları by Issue Date

Results Per Page

Sort Options