Browsing by Author "Akca S."
Now showing 1 - 10 of 10
Results Per Page
Sort Options
Item The analysis of violence against the nurses who are in employee status in Mugla State hospital, Turkey(2012) Picakciefe M.; Akca S.; Elibol A.; Deveci A.; Yilmaz N.; Yilmaz U.E.Objektive: Workplace violence in the co untry, especially in the health system remains obscure. The search of the relationship using an intersectional, analytical survey between the working conditions and violence exposure of the nurses who work in Muǧla State Hospital was aimed in the study. Materials and methods: Of the 310, 268 nurses participated, yielding a response rate of 86.5%. The data was examined by using Fisher's Exact Test, Pearson Chi-Square Test and Logistic Regression. In result, it was found that 85.8% of the nurses were exposed to violence, with 70.4% of the violence coming from the relatives of patients. Results: 77.2% of the nurses were exposed to verbal abuse while 71.4% were physically assaulted. Unfortunately, 98.4% of the abused did not report the physical abuse. 91.3% of the nurses always felt violence anxiety, while 92.9% of them thought that their instutions do not make an effort for the security systems. According to logistic regression analysis, having worked 21 years and over, night work and having felt a violent encounter in the workplace, significantly increases the frequency of meeting with violence of nurses. Conclusion:In conclusion we found that the nurses were exposed to multiple forms of violence. This was correlated with their monthly average income, marrital status, parental status, work status, night shifts, overtime, rotational shifts, total and daily work hours.Item Cathodoluminescence and thermoluminescence of ZnB2O4:Eu3+ phosphors prepared via wet-chemical synthesis(Elsevier Ltd, 2019) Dogan T.; Tormo L.; Akca S.; Kucuk N.; Guinea J.G.; Karabulut Y.; Ayvacikli M.; Oglakci M.; Topaksu M.; Can N.In present work, a series of Eu doped zinc borate, ZnB2O4, phosphors prepared via wet chemical synthesis and their structural, surface morphology, cathodoluminescence (CL) and thermoluminescence (TL) properties have been studied. Phase purity and crystal structure of as-prepared samples are confirmed by X-ray diffraction measurements (XRD) and they were well consistent with PDF card No. 39-1126, indicating the formation of pure phase. The thermoluminescence (TL) behaviors of Eu activated ZnB2O4 host lattice are studied for various beta doses ranging from 0.1 to 10 Gy. The high-temperature peak of Eu activated sample located at 192 °C exhibited a linear dose response in the range of 0.1–10 Gy. Initial rise (IR) and peak shape (PS) methods were used to determine the activation energies of the trapping centres. The effects of the variable heating rate on TL behaviour of Eu activated ZnB2O4 were also studied. When excited using an electron beam induced light emission (i.e cathodoluminescence, CL) at room temperature (RT), the as-prepared phosphors generate reddish-orange color due to predominant emission peaks of Eu3+ ions located at 576–710 nm assigned to the 5D0→7FJ (J=1,2,3, and 4) transitions. The maximum CL intensity for Eu3+ ions at 614 nm with transition 5D0→7F2 was reached Eu3+ concentration of 5 mol%; quenching occurred at higher concentrations. Strong emission peak for Eu3+ ions at 614 nm with transition 5D0→7F2 is observed. The CL experimental data indicate that ZnB2O4:Eu3+ phosphor as an orange-red emitting phosphor may be promising luminescence materials for the optoelectronic applications. © 2018 Elsevier Ltd and Techna Group S.r.l.Item Thermoluminescence analysis of beta irradiated ZnB 2 O 4 : Pr 3+ phosphors synthesized by a wet-chemical method(Elsevier Ltd, 2019) Akca S.; Oglakci M.; Portakal Z.G.; Kucuk N.; Bakr M.; Topaksu M.; Can N.In this paper we describe the thermoluminescence (TL) characteristics of ZnB 2 O 4 :Pr 3+ phosphors with Pr concentrations varying between 0.2 and 1 mol% prepared by a wet-chemical method. The TL glow curves of the phosphor sample consisted of three peaks located at 71 °C (P1), 124 °C (P2) and 233 °C (P3). The TL intensity increased with the beta dose ranging from ∼0.1 to ∼20 Gy. Dose response, reproducibility and trapping parameters of TL glow curves were evaluated to clearly reveal thermoluminescence features. We observed that TL intensity of P2 and P3 peaks decreases as the heating rate increases. Trap parameters were estimated via the Hoogenstraaten, Booth-Bohun-Parfianovitch, the initial rise methods combined with T m −T stop experiment and TLanal CGCD program. Heating rates were varied to use in the Hoogenstraaten analyses. The T m −T stop investigations on regenerated TL signals for P1 and P2 peaks indicated that ZnB 2 O 4 :Pr 3+ phosphor has four electron trap levels with energy values in the range of 0.5–1.5 eV These four traps have first order kinetic and are formed at high temperature region. Resulting values are utilized as a reference for the CGCD procedure and the trapping parameters from the TL glow curves are calculated. The figure of merit (FOM) of the TL glow curve during curve fitting procedures is found to be 2.019%. The intensities of the main dosimetric peaks appeared at 124 °C and 233 °C exhibits good linear dose response up to 20 Gy. These results provide valuable knowledge for use of the characteristics of Pr doped ZnB 2 O 4 in dosimetry research, just need to eliminate low temperature TL peak. © 2019 Elsevier LtdItem Enhancing the blue luminescence behaviour of the Li co-doped novel phosphor ZnB2O4: Tm3+(Elsevier Ltd, 2020) Kucuk N.; Kaynar Ü.H.; Akca S.; Alajlani Y.; Yin L.; Wang Y.; Garcia Guinea J.; Bulcar K.; Dogan T.; Karabulut Y.; Ayvacikli M.; Canimoglu A.; Topaksu M.; Can N.Here we report a detailed structural analysis, and properties of the cathodoluminescence (CL), photoluminescence (PL) and 3D thermoluminescence spectra of the Tm3+ incorporated ZnB2O4 phosphor successfully synthesized through wet-chemical synthesis. The formation of a single-phase compound is verified through X-ray diffraction (XRD) studies. The phosphor shows an efficient blue emission located at 458 nm corresponding to 1D2→3F4 under both a low voltage electron beam and UV excitation. The optimal concentration of the doped Tm3+ is 0.5 mol% in CL and PL measurements. The corresponding concentration quenching mechanism is confirmed to be a multipole-multipole interaction, and the critical distance between Tm3+ ions is estimated to be 34 Å. Incorporating Li+ remarkably enhances the luminescence intensity probably because of the charge compensation effect. Li ions are speculated to fill the defects in the ZnB2O4 host and then the excitation energy transfers from the host to Tm3+. Surprisingly, the thermoluminescence spectra of ZnB2O4:Tm3+ and Li+ co-doped ZnB2O4:Tm3+ recorded in the temperature range 30–400 °C follow a different pattern compared with PL and CL data. The dominant signals come from Tm3+ sites. Above room temperature, the Tm3+ ions do not show the peak temperature movement, but do exhibit a different pattern with the addition of co-doped Li+ ions. These results indicate that these phosphors are promising candidates for luminescence-based optoelectronic devices. © 2020 Elsevier B.V.Item Synthesis and photoluminescence characteristics of Dy incorporated MoO3 phosphor: Suppression concentration quenching(Elsevier Ltd, 2020) Ayvacikli M.; Kaynar Ü.H.; Karabulut Y.; Canimoglu A.; Bakr M.; Akca S.; Can N.A series of MoO3:Dy3+ phosphors have been synthesized via the gel-combustion method. The X-ray and photoluminescence (PL) emission spectra were employed to characterize the obtained phosphors. The prepared samples were characterized through XRD measurements and exhibited that Dy3+ ions can be successfully incorporated into the host material. The PL emission bands of Dy3+ doped MoO3 were observed at 486 nm, 574 nm and 666 nm which are assigned to the transitions of 4F9/2 → 6H15/2, 4F9/2 → 6H13/2 and 4F9/2 → 6H11/2, respectively. Concentration quenching were largely taken into consideration as one of the crucial aspects limiting the application range of phosphors in today's modern world. An abnormal thermal quenching dependence was reported when Dy3+ ions were incorporated into MoO3 host matrix. In order to understand the origin of this beneficial behaviour, energy transfer processes occurring via radiative and nonradiative mechanisms were investigated to elucidate this suppression of the concentration quenching. © 2020 Elsevier LtdItem Thermoluminescence of β-particle induced Bern-4M muscovite(Elsevier Ltd, 2020) Portakal-Uçar Z.G.; Akca S.; Balci-Yegen S.; Yüksel M.; Dogan T.; Souadi G.O.; Parlak O.; Topaksu M.; Can N.Bern-4M muscovite from Switzerland was investigated via X-ray diffraction (XRD), energy dispersive spectrometer (EDS) and thermoluminescence (TL). Muscovite has the theoretical formula KAl2(AlSi3O10)(FOH)2, or (KF)2(Al2O3)3(SiO2)6(H2O). Chemical analysis of the muscovite sample was carried out using EDS for major oxides. The results indicate that muscovite includes oxygen (59.1%), silicon (18.86%), and aluminum (15.22%) as major elements and contains low concentrations of potassium, magnesium, and sodium. In standard muscovites potassium use to be 10% and oxygen 47%, probably the sample was strongly lixiviated before the analysis. The thermoluminescence spectrum exhibits a wide glow peak located at 250 °C with a shoulder peak at high temperature region. Trap depth and frequency factor were calculated using Hoogenstraaten's method and found to be 1.16 eV and 1.4 × 1010 s−1, respectively. Reproducibility test indicated that the values within ±5% were obtained after 15 cycles. The storage time experiments were performed for different time periods up to 1 week for dark fading. © 2020 Elsevier LtdItem Eu3+ and Dy3+ doped La2MoO6 and La2Mo2O9 phosphors: Synthesis and luminescence properties(Elsevier Ltd, 2020) Kaynar Ü.H.; Cam Kaynar S.; Alajlani Y.; Ayvacikli M.; Karali E.; Karabulut Y.; Akca S.; Karali T.; Can N.We report a detailed structural analysis and properties of the photoluminescence (PL) and thermoluminescence (TL) spectra of Eu3+ and Dy3+ incorporated into novel La2MoO6 and La2Mo2O9 phosphors synthesized successfully through gel combustion synthesis. The formation of a tetragonal phase and a cubic structure were verified for La2MoO6 and La2Mo2O9 phosphors via X-ray diffraction (XRD) studies. Dy doped samples exhibited blue and green emissions at 480 nm (4F9/2 →6H15/2) and 572 nm (4F9/2 → 6H13/2), and also Eu doped samples showed a sharp emission peaks at 612 and 619 nm (5D0 →7F2) upon 349 nm pulse laser excitation. Peak shape (PS) technique was utilised to determine activation energy, frequency factor and order of kinetics associated with the main glow curves in undoped and Eu and Dy doped samples after X-ray irradiation. The present findings suggest that Eu and Dy incorporated La2MoO6 and La2Mo2O9 phosphors are highly auspicious candidates for applications in solid-state lighting. © 2019 Elsevier LtdItem A study on thermoluminescence behaviour of Eu doped LaB3O6 irradiated with beta particles(Elsevier Ltd, 2020) Halefoglu Y.Z.; Oglakci M.; Portakal Z.G.; Akca S.; Souadi G.O.; Canimoglu A.; Topaksu M.; Can N.Lantanium triborate (LaB3O6) samples doped with Eu3+ ions are synthesized via combustion route. This study primarily reports the thermoluminescence (TL) behaviour of LaB3O6 host. X-ray diffraction (XRD) pattern reveals that LaB3O6 exhibits a single phase matched with JCPDS card 98-002-3609. Dose response, reusability and trap parameters of TL glow curves are evaluated to clearly reveal the TL features. The results show that the peak positions of TL glow curves are affected by varying the concentration of Eu. The experimental results obtained from the dose-response of LaB3O6:Eu3+ (1%) which has given high TL intensity reveal that the intensity of TL given by the total area under glow curves shows a good linearity (b= 0.997) up to 20 Gy. In addition, the minimum detectable dose (MDD) value has been calculated as 1.45 mGy with a standard deviation of 0.8%. Main TL peak maxima is observed around 197 °C with heating rate (HR) of 2 °Cs−1. An anomalous HR effect is observed for this peak in the range of 0.5–20 °Cs−1 with beta dose of 5 Gy. To find the overlapping peak numbers and determine the kinetic parameters of the main peak of LaB3O6:Eu3+ (1%), Initial Rise (IR) method using Tm−Tstop experiment and CGCD analysis have been performed for HRs of 0.5 and 2 °Cs−1. It can be said that the results of the methods are in good agreement when same trap numbers (at least eight separate peaks for both) and close energy values are taken into consideration. Deconvolution procedure of LaB3O6: Eu3+(1%) is performed using general order kinetic equation by R studio ‘tgcd’. Additionally, the lifetimes of each deconvolved peaks by CGCD of Eu activated LaB3O6 (1%) have been calculated. Based on the results it can be put forth that TL characteristics of Eu doped LaB3O6 can be used as a promising material for thermoluminescence dosimetry-environmental applications. © 2019 Elsevier LtdItem Comprehensive study of photoluminescence and cathodoluminescence of Eu and Tb doped Mg2SiO4 prepared via a solid-state reaction technique(Elsevier B.V., 2020) Ucar Z.G.P.; Akca S.; Dogan T.; Halefoglu Y.Z.; Kaynar U.H.; Ayvacikli M.; Guinea J.G.; Topaksu M.; Can N.We report narrow-band green-red emitting Mg2SiO4 phosphors successfully synthesized through solid-state reaction method, and the cathodoluminescence (CL) and photoluminescence (PL) properties of the samples were investigated in detail. Under electron beam and 275 nm excitation, Mg2SiO4 phosphors doped with various Eu3+ and Tb3+ concentrations in the range of 1 mol % up to 10 mol % exhibit typical green and red emissions, respectively. Tb doped samples were efficiently excited by a low voltage electron beam and UV light, yielding several emission peaks between 370 and 760 nm, and produced a bright green light peaking at 541 nm due to the 5D4 →7F5 transition. Eu3+ doped samples exhibited CL and PL emission spectra from 5D0 to 7Fj manifold transitions of Eu3+. A strong red-light emission peaking at 610 nm also supports the incorporation of Eu3+ ions. A concentration quenching effect was observed and discussed for both phosphors. The optimal doping concentration of Eu3+ and Tb3+ doped phosphors was 7 mol %. In view of the outstanding performance in the PL and CL, the Mg2SiO4:Eu3+, Tb3+ can be considered as a promising green and red phosphor in solid-state lighting applications. © 2020 Elsevier B.V.Item The Effects of Grape, pomegranate, Sesame Seed Powder and Their Oils on Probiotic Ice Cream: Total phenolic contents, antioxidant activity and probiotic viability(Elsevier Ltd, 2021) Akca S.; Akpinar A.The present study aimed to produce probiotic ice cream, containing Lactobacillus rhamnosus and Bifidobacterium animalis subps. lactis BB12 as the starter cultures, by adding vegetable seed pulp powder (sesame, pomegranate seed, and grape seed) and oils of these seeds to the ice cream mixtures and to examine the effects of these additions on pH, acidity, total phenolic content, flavonoid content, antioxidant capacity and the probiotic viability of Lactobacillus rhamnosus and Bifidobacterium animalis subps. lactis BB12 in ice cream samples stored at −20 °C for 90 days. Total phenolic content, flavonoid content, and antioxidant capacity were evaluated on the first and last day of the storage. Vegetable seed powders and oils did not affect the pH and acidity values of the ice cream samples. The pulp powders and oils used contributed to preserving the viability of probiotic bacteria during storage. Among the seed pulp powders, the grape seed had the highest phenolic content and antioxidant activity. Especially, ice creams containing grape seed powder, grape seed powder + seed oil, and pomegranate seed powder promoted the development of probiotic microorganisms in these ice cream samples due to the high phenolic components and antioxidant activity. The total phenolic content and antioxidant activity of seed powders and oils were parallel to the total phenolic content and antioxidant activity of ice creams produced using these powders and oils. It can be concluded that grape seed powder and its oil can be used as a natural ingredient to develop a novel ice cream with high nutritional antioxidant activity. © 2021