Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Kahraman, Gökhan(4)
- Yön, Burak(4)
- Biryan, Fatih(3)
- Gul, Muhammet(3)
- Pihtili, Güzin(3)
- Qader, Ibrahim Nazem(3)
- Aydin, C.(2)
- Aydin, H.(2)
- Calayır, Yusuf(2)
- Er, Besir(2)
- Erten, Fusun(2)
- Kanca, Muhammed Sait(2)
- Kök, Mediha(2)
- Onat, Onur(2)
- Orhan, Cemal(2)
- Pekdemir, Mustafa Ersin(2)
- Sahin, Kazim(2)
- Tasar, Neslihan(2)
- Taskin, M.(2)
- Taşgın, Yahya(2)
- Topal, Murat(2)
- Utku, Anıl(2)
- Yucesan, Melih(2)
- Öbek, Erdal(2)
- Öncü, Mehmet Emin(2)
- Acisu, Tutku Can(1)
- Adiguzel, Ragip(1)
- Aker, Onur(1)
- Alofaysan, Hind(1)
- Amoozegar, Azadeh(1)
- Arslan Topal, E. Işıl(1)
- Arı, Üzeyir(1)
- Atalar, Aydın(1)
- Ayazgök, Büşra(1)
- BARUT, Abdulkadir(1)
- Bakır, Dursun(1)
- Barut, Abdulkadir(1)
- Bayrakdar, Cihan(1)
- Bektaş, İdris(1)
- Bulut, N.(1)
Yayınlar
- MakaleYalnız künye2024Scopus SJRQ2Evaluating the metallographic properties and performance of heat transfer by natural convection of graphene-coated glass used for heating
Kahraman, Gökhan; Taşgın, Yahya
In this study, a decorative electric heater was manufactured to reduce carbon emissions related to residential and office heating, and this heater was metallographically evaluated. In addition, the heating performance of the manufactured plate was investigated by examining its heat transfer capacity by natural convection. For this purpose, the surface of the tempered glass plate was coated with graphene by spraying to improve its electrical and heat conduction properties. Copper strips were attached to both sides of the plate to allow for an electric current. The plate was connected to mains electricity, and its change in surface temperature over time was measured. Using the measured temperature values, the heat transfer rate by natural convection on the plate surface was calculated. As a result of the calculations, it was determined that the graphene-coated tempered glass plate reached a heating performance of 40 watts after 2400 s of electrical energy supply. This value can be increased by increasing the heat transfer surface area. This study, taking advantage of the excellent thermophysical properties of graphene, will contribute to other studies conducted in this field.
AtıfScopus2WoS2OpenAlex2
İncele - DüzeltmeAçık Erişim2024Scopus SJRQ2Correction: Genotoxic effects of copper nanoparticles on Vicia pannonica Crantz. root meristem cells (Journal of Nanoparticle Research, (2024), 26, 8, (185), 10.1007/s11051-024-06096-y)
Tasar, Neslihan
The original version of this article unfortunately contained incorrect Figs. 2, 3, and 4. Lastly, Open access cancellation shall be initiated. The approval manager initially approved the article by mistake, and they approved it above their maximum article threshold by accident. (Figure presented.) (Figure presented.) (Figure presented.) A Adhesion in prophase, B distorted prophase, C metaphase, D distorted metaphase, E non-collection in metaphase plaque, F lagging chromosome in metaphase, G adhesion in metaphase, H chromosome loss in metaphase, I chromosome breakage in metaphase, J asynchronous division in anaphase, K distorted anaphase, L lagging chromosome in anaphase, M polar deviation in anaphase, N chromosome bridges in anaphase, O advance in anaphase, P polar deviation in telophase, R bridge in telophase, S lagging chromosome in telophase, T distorted telophase, U adhesion in telophase (magnification = × 100) A The scanning electron microscopy (SEM) image of the control group, EDS characteristic spectrum, and mapping image. B The scanning electron microscopy (SEM) image of the sample that was prepared with 50 ppm Cu NPs, EDS characteristic spectrum, and mapping image. C The scanning electron microscopy (SEM) image of the sample that was prepared with 150 ppm Cu NPs, EDS characteristic spectrum, and mapping image. D The scanning electron microscopy (SEM) image of the sample that was prepared with 300 ppm Cu NPs, EDS characteristic spectrum, and mapping image The XRD plots of the samples that were obtained from V. pannonica plant grown with Cu (40–60 nm) NP
- MakaleAçık Erişim2024Scopus SJRQ2Genotoxic effects of copper nanoparticles on Vicia pannonica Crantz. root meristem cells
Tasar, Neslihan
With the increasing use of metal nanoparticles, their access to the food chain has become the main concern for scientists. The present study sheds light on the copper nanoparticles (Cu NPs), which are widely used in many industries today. For this purpose, Vicia pannonica Crantz., a common fodder plant, was used and exposed to metal-based Cu NPs. To determine the genotoxic effects on root meristem cells, total of 3 different concentrations (50 ppm, 150 ppm, and 300 ppm) of Cu NPs and the control in deionized water solutions were prepared. The determination of the accumulation and elimination of Cu NPs in Vicia pannonica used in the study was carried out using with X-ray diffraction (XRD), scanning electron microscopy (SEM), SEM element mapping, and energy dispersive X-ray diffraction (EDS) characteristic spectrum analysis. All doses of Cu NPs caused significant decreases in the Mitotic index of V. pannonica meristem cells compared to the control. Multiple analyzes carried out in the study showed that Cu NPs caused abnormalities in cell division such as C-metaphase, polar aberration, deconstructed anaphase, chromosome breakage, loss of genetic material, failure to assemble in the metaphase plate, deconstructed metaphase, asynchronous division remaining chromosome in metaphase, adhesion, deconstructed prophase, advanced chromosomes, and chromosome bridges in anaphase. Results support that Cu NPs have a genotoxic effect on V. pannonica.
AtıfScopus5WoS2OpenAlex6İncele - MakaleAçık Erişim2023Scopus SJRQ2Preparation of composite supported phase change materials from inorganic-based microcapsules of cetyl alcohol and investigation of their phase change material (PCM) behaviors
Karabulut, Serap; Sekerci, Memet; Adiguzel, Ragip; Karagoz Genc, Zuhal
In this study, cetyl alcohol (CA) (CH3(CH2)15OH), which is a fatty alcohol, was microencapsulated by the coacervation method with the titanium-n-butoxide (TNBO). Firstly, at the beginning of the experimental process by thermal and structural analyses, the CA was determined as having a phase change material (PCM) property, then it was microencapsulated with TNBO. In the second step of the study, barite, boron nitride, marble powder, and fly ash were separately added to prepare a series of microencapsulated with TNBO. Lastly, structural and thermal properties of both microencapsulated PCM and composite supported microencapsulated PCMs (CSM-PCMs) have been analyzed by FTIR, DSC, TGA, and SEM devices. Surprisingly, the SEM image of CA turned from torn fiber structure into a particulate structure in the form of groundnut in the SEM images of the microencapsulated CA-Ti taken at different magnifications. After the thermal cycling test, the same analyses have been made before and after thermal cycling to compare the structural and thermal properties. It has been investigated whether to use as insulation material. It is concluded that the most suitable samples, compared with structural and thermal properties, are barite (B) and boron nitride (BN) with microencapsulated samples. The obtained results are shown that CATi-B and CATi-BN are CSM-PCMs and could be suggested in terms of thermal energy storage in buildings as promising PCMs.
AtıfScopus3WoS3OpenAlex3İncele - MakaleAçık Erişim2022Scopus SJRQ1A Bayesian BWM and VIKOR-based model for assessing hospital preparedness in the face of disasters
Saner, Halit Serdar; Yucesan, Melih; Gul, Muhammet
Hospitals are the first point of contact for people in the face of disasters that interfere with the daily functioning of life and endanger health and social life. All preparations should be made considering the worst possible conditions and the provided service should continue without interruption. In this study, a multi-criteria decision-making model was developed to evaluate disaster preparedness of hospitals. This decision model includes Bayesian best–worst method (BBWM), the VlseKriterijumska Optimizacija I Kompromisno Resenje (VIKOR) and technique for order preference by similarity to ideal solution (TOPSIS) methods. With the proposed decision model, six main criteria and 34 sub-criteria related to disaster preparedness of hospitals were considered. The criteria and sub-criteria evaluated in pairwise comparison manner by the experts were weighted with BBWM. These weight values and the data obtained from the six Turkish hospitals were combined to provide inputs for VIKOR and TOPSIS. In addition, a comparative study and sensitivity analysis were carried out using weight vectors obtained by different tools. BBWM application results show that the “Personnel” criterion was determined as the most important criterion with an importance value of 26%. This criterion is followed by “Equipment” with 25%, “Transportation” with 14%, “Hospital building” and “Communication” with 12%, and “Flexibility” with 11%. Hospital-2 was determined as the most prepared hospital for disasters as a result of VIKOR application. The VIKOR Q value of this hospital was obtained as 0.000. According to the results of the comparative study, Hospital-2 was determined as the most disaster-ready hospital in all six different scenarios. This hospital is followed by Hospital-4 (Q = 0.5661) and Hospital-5 (Q = 0.7464). The remaining rankings were Hospital-6, Hospital-3 and Hospital-1. The solidity of the results was checked with TOPSIS. Based on TOPSIS application results, Hospital-2 was again found the most-ready hospital. The usage of BBWM in this study enabled the expert group’s views to be combined without loss of information and to determine the criteria and sub-criteria weights with less pairwise comparisons in a probabilistic perspective. Via the “Credal ranking”, which is the contribution of BBWM to the literature, the interpretation of the hierarchy between each criterion has been performed more precisely.
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İncele - MakaleAçık Erişim2022Scopus SJRQ1How Covid-19 pandemic and partial lockdown decisions affect air quality of a city? The case of Istanbul, Turkey
Celik, Erkan; Gul, Muhammet
The world is currently struggling with a new type of coronavirus (2019-nCoV) pandemic that first appeared in Wuhan, China, and then spread to almost all countries. As in other countries of the world, public authorities in Turkey are implementing many preventive and mitigating partial lockdown (PL) actions against the virus's effects. Some decisions and policies implemented before and after March 11, 2020, when the first virus case has been identified, have reduced people and traffic circulation, which has also turned into some improvements in air quality. At this point, this study aims to investigate how this pandemic affects the air quality of a metropolis. A case study of the city of Istanbul, the most affected city with more than half of Turkey's cases, is performed. In our analysis, we observe, compare, and discuss the impact of the COVID-19 pandemic and PL decisions on Istanbul city's air quality. We consider the particulate matter (PM10), sulfur dioxide (SO2), carbon monoxide (CO), nitrogen dioxide (NO2), nitrogen oxide (NO), nitrogen oxides (NOx), and ozone (O3) concentrations. We used data from 19 air monitoring stations (AMSs) and obtained improvements in the air quality for the pandemic period. In summary, the concentration levels in PM10, NO2, NO, and NOx result in a clear decline in pandemic times compared to the normal times in Istanbul. On the other hand, a non-homogenous trend for SO2 and CO concentrations is observed for different AMSs. A partial increase in O2 concentration is obtained in the comparison of before and during the PL period.
AtıfScopus15WoS13OpenAlex22İncele - MakaleAçık Erişim2022Scopus SJRQ2Biocompatible PLA/PCL blends nanocomposites doped with nanographite: Physico-chemical, and thermal behaviour
Qader, Ibrahim Nazem; Pekdemir, Mustafa Ersin; Coşkun, Meltem; Kanca, Muhammed Sait; Kök, Mediha; Dağdelen, Fethi
There is a great interest in nano-graphite due to its wide application in nanotechnology and important physical properties. Nanocomposites based on polymers and blends are important in the development of traditional polymers and in improving their usage areas. The aim of this study is to improve physico-chemical, and thermal behavior of poly(lactic acid) / poly(ε-caprolactone) (PLA/ PCL) blend by doping nano-graphite (NG) with different amounts and make the characterization of these nano-composites. It was observed that NG affected the temperature at which nanocomposites decompose. Also, the nanoparticles incorporated in the polymer blend become locked between the polymer filaments, speeding up the composites' decomposition. NG has significantly higher melting and evaporation temperature than PLA and PCL, so more residues were left as the quantity of NG rose. There was no significant change in the Tg and Tm peaks in the DSC experiment due to the inclusion of NG. While the NG particles raised the enthalpy of phase transition in general. The sharpness of the XRD peaks and the crystallinity of the nanocomposites both enhanced as the amount of NG in the blend was increased. Shape memory has been demonstrated to be a remarkable characteristic of thermos-sensitive PLA / PCL blend. Although the trained nanocomposite recovered most of its predetermined shape, increasing NG concentration in the composite may diminish its recovery behavior because.
AtıfScopus22WoS22OpenAlex25İncele - MakaleYalnız künye2022Scopus SJRQ2Production and properties of epoxy matrix composite reinforced with hollow silica nanospheres (HSN): mechanical, thermal insulation, and sound insulation properties
Demir, Eda; Güler, Ömer
Hollow silica nanospheres (HSNs) have superior properties such as low density, low dielectric constant, low thermal conductivity, good sound absorption, dispersibility, fluidity, and stability. They have the potential to be utilised as a reinforcing material in the development of next generation composites due to their properties. Epoxy is one of the commonly utilised polymers in today’s technology. Production of epoxy matrix composite materials reinforced with particles having superior properties will open up new application areas for epoxy. In this study, mesoporous HSNs were produced. The mechanical, thermal and sound insulation properties of the composite were examined by reinforcing these mesoporous HSNs to the epoxy matrix. The epoxy matrix was reinforced with HSNs at 1 wt.%, 5 wt.%, and 10 wt.%. When the concentration of HSNs in the epoxy matrix was increased, its strength increased and its ductility decreased. While the non-reinforced epoxy had a tensile strength of 36.45 MPa, but the tensile strength of epoxy at the end of 10% HSN reinforcement reached 89.06 MPa. The strain % reduced in half. The sound insulation properties of epoxy improved as the concentration of HSNs increased. Thermal conductivity coefficient dropped up to a 5% reinforcement ratio, and then increased slightly at a 10% reinforcement ratio. The microstructure analyses indicated that when the reinforcement ratio increased, difficulties in the distribution of reinforcements to the matrix appeared. Furthermore, it was observed that when the matrix/reinforcement interface was improved, the properties of the composite improved.
AtıfScopus14WoS13OpenAlex12İncele - MakaleAçık Erişim2022Scopus SJRQ1Corrosion behavior and crystal-microstructural analysis of non-equiatomic NiTi shape memory alloys
Kanca, M. Sait; Kök, Mediha; Qader, Ibrahim Nazem
NiTi shape memory alloys (Nitinol) are one of the most widely used families of smart materials that are used in smart systems and medical applications. The NiTi alloy with a composition of around 50 at. % Ni is very sensitive and just a small change in the components can make a big difference in the physical properties of the alloy. In this study, five non-equiatomic NiTi alloys with different compositions were fabricated with arc-melting in a controlled atmosphere. The crystal structure and morphology of the alloys were analyzed with x-ray diffraction (XRD) and scanning electron microscope (SEM), also the caloric properties of the alloys were investigated as a function of composition. Additionally, the samples were examined by the Tafel test to determine the corrosivity rate for one year in a simulated body fluid. The XRD and DSC results showed that only Ni44.56Ti55.44 at. % has martensite phase at room temperature, while the other alloys with higher Ni contents did not show martensitic phase transformation for the range of 230 K to more than 400 K. It was found that the alloys have corrosion rate around 10–4 mmpy which has comparably better than CuAlNi-based alloys. On the other hand, it was found that the corrosivity does not depend on the matrix phase of the NiTi alloy, but the composition ratio and other secondary phases play an important role.
AtıfScopus4WoS4OpenAlex6İncele - MakaleAçık Erişim2022Scopus SJRQ1Field reconnaissance and structural assessment of the October 30, 2020, Samos, Aegean Sea earthquake: an example of severe damage due to the basin effect
Onat, Onur; Yön, Burak; Öncü, Mehmet Emin; Varolgüneş, Sadık; Karaşin, Abdulhalim; Cemalgil, Selim
An earthquake with a magnitude ranging from Mw = 6.9 (KOERI) to Mw = 7.0 (USGS) struck Samos Island in the Aegean Sea on October 30, 2020, with an epicentre 70 kms from the İzmir city centre in Turkey. The earthquake took place at 14:51 local time (11:51 UTC). The peak ground acceleration (PGA) of this earthquake was recorded to be 0.179 g at the epicentre of the earthquake. This earthquake occurred at a depth of 17.26 km (AFAD (2020) İzmir Earthquake Report, (In Turkish)) and lasted 16 s. The main shock from the earthquake triggered a tsunami that hit the building stocks built near the coast. During the gradual deregulation of COVID-19 pandemic regulations, various events caused considerable damage to the building stock, particularly in the Izmir Seferihisar and Bayraklı regions and resulted in a massive disruption of daily habits. The main shock caused 117 deaths in both Turkey and Greece, and 1632 people were also injured in Turkey. Moreover, several injuries occurred in Greece. A total of 103 buildings collapsed, 700 were severely damaged, 814 buildings were moderately damaged, and 7889 were slightly damaged. The basic aim of this paper is to briefly present the past and present seismotectonic characteristics of the region, present building stock, and former structural conditions before the earthquake, assess structural performance and classify distinguished earthquake-induced failures and damage due to the basin effect.
AtıfScopus30WoS28OpenAlex29İncele - MakaleAçık Erişim2021Scopus SJRQ1Evaluation of non-carcinogenic health risks of thallium in grapevine exposed to mine waters of an abandoned mining region in Turkey
Topal, Murat; Arslan Topal, E. Işıl; Öbek, Erdal
In this study, non-carcinogenic health risks of thallium in grapevine exposed to mine waters of an abandoned mining region in Turkey were evaluated. The values of thallium were investigated in leaves, stems, and roots. Translocation factors (TF) and bioaccumulation concentration factors (BCF) were determined. The maximum thallium value in grapevines (root) was 2.34 ± 0.12 mg/kg. Thallium values in grapevine were stem < leaf < root. The bioconcentration value calculated in our study is higher than 1 showing thallium bioaccumulation from the mine water to grapevines. Translocation factor value is calculated as 1.20. The high total estimated daily exposure dose (TED) in grapevines was determined as 1.10E-02 mg/kg day for children. TEDs values in grapevines were observed as male < female < children, respectively. The maximum HQ risk value for male was observed as 1060 for children. The non-carcinogenic risk values were children > female > male. Hazard index values of thallium in grapevines were ingestion < dietary. As a result, hazard and total hazard index values were > 1 for thallium in grapevines. Therefore, there are non-carcinogenic health risks of thallium in grapevine exposed to mine waters of an abandoned mining region.
AtıfScopus3WoS1OpenAlex2İncele - MakaleAçık Erişim2021Scopus SJRQ124 January 2020 Sivrice-Elazığ, Turkey earthquake: geotechnical evaluation and performance of structures
Sayın, Erkut; Yön, Burak; Onat, Onur; Gör, Mesut; Öncü, Mehmet Emin; Tuğrul Tunç, Esra; Bakır, Dursun; Karaton, Muhammet; Calayır, Yusuf
The January 24, 2020 Sivrice-Elazığ (Mw = 6.8) earthquake occurred on the East Anatolian Fault zone. Main shock of this earthquake was occurred 20:55 at local time. The Peak Ground Acceleration was equal to 0.3 g at the epicenter (Sivrice district) of the earthquake. Even though the main shock was moderate, its effects on the structures were rather serious. The main shock caused significant damage and resulted in 41 casualties. 1540 buildings were damaged moderately, while 8519 buildings were damaged heavily and collapsed. This main shock effected four cities surrounded the epicenter due to its shallow earthquakes. The purpose of this paper is to summarize past and present seismic characteristics of the earthquake region. In addition, the aim of this paper is to summarize the seismotectonic of the region, the general characteristics of the earthquake and more specifically to report on the structural damage, and structural damage caused by the earthquake, observed during the site investigation. The damages were classified for reinforced concrete structures, masonry dwellings and non-residential structures. All distinguished earthquake induced failures and damages were discussed. Moreover, lessons learned were presented in this study.
AtıfScopus74WoS68OpenAlex93İncele - MakaleYalnız künye2021Scopus SJRQ2Nanofiller reinforced biodegradable PHA/PLA composites: physico-chemical, thermal and dielectric properties
Torğut, Gülben; Gürler, Nedim
In this study, the electrical, thermal, morphological and physical properties of polyhydroxyalkanoate (PHA) and polylactic acid (PLA) blends and its nanocomposites prepared in different content of montmorillonite (3%wt, 5%wt, 7%wt) were investigated. Biodegradable blends of PHA/PLA were prepared in different compositions ranging from 30–70%. Nanocomposite films were analyzed by Fourier Transform Infrared (FTIR), Thermogravimetric Analysis (TGA), Differential Thermal Analysis (DTA) and scanning electron microscopy for morphology (SEM). The effects of the amount of MMT used as a reinforcing filler on the morphology, color, opacity, thermal stability, and dielectric properties of PHA/PLA films were investigated. SEM analyses showed good interaction between MMT and PHA/PLA film. As the MMT concentration increases, the transparency of the films decreases. In addition, MMT has improved thermal stability. Also, the dielectric properties and electrical conductivity of nanocomposite films were studied. The measurements were performed at frequencies between 100 Hz to 10 kHz at room temperature. As the frequency increased, dielectric permittivity (έ), the dielectric loss (ε'') and the electrical conductivity (σ) decreased and remain constant at high frequencies. έ, ε'' and the σ increased with increasing MMT content.
AtıfScopus27WoS22OpenAlex28İncele - MakaleAçık Erişim2021Scopus SJRQ2Study on the thermal and electrical properties of novel poly[propyl acrylate-co-phenyl methacrylate] containing acetamido group
Biryan, Fatih; Pihtili, Güzin
In the available research, firstly a new 3-acetamido phenyl acrylate (APhA) monomer and a novel copolymer containing acetamido phenyl group were synthesized. 3-acetamido phenyl acrylate (APhA) monomer was acquired by the reaction of acryloyl chloride and N-(3-hydroxyphenyl) acetamide. 3-acetamido propyl methacrylate (AAPMA) monomer was prepared in our previous study. A series of copolymers were prepared using these monomers in different mole ratios by free-radical polymerization method at 70 °C The structure of P(AAPMA-co-APhA) copolymer systems was characterized by FT-IR and NMR techniques. Thermal characteristics of P(AAPMA-co-APhA) copolymers were evaluated through thermogravimetric analysis (TGA) and differential scanning calorimeter (DSC) in an N2 atmosphere. Due to the presence of the amide group, we can say that the polymer with the least weight loss and the highest residue percentage at 500 °C is poly(APhA). AC electrical conductivity and dielectric and electrical parameters were analyzed in a range of 100 Hz–20 kHz frequency. The dielectric constant values of poly(AAPMA-co-APhA0.63) and P(AAPMA-co-APhA0.30) were 4.98 and 4.57 respectively. According to the results, the dielectric value decreased as the APhA units increased.
AtıfScopus5WoS5OpenAlex5İncele - MakaleAçık Erişim2021Scopus SJRQ1Assessment of potential health risk associated with the use of Cladophora fracta as mulch
Öbek, Erdal; Topal, E. Işıl Arslan; Topal, Murat
In this study, cadmium, copper, nickel, zinc, chromium, manganese and lead were determined in Cladophora fracta present in Lake Hazar (Turkey). The health risks (non-carcinogenic and carcinogenic) of heavy metals associated with the use of Cladophora fracta as mulch were also determined. Bioconcentration factor (BCF) and metal pollution index (MPI) were calculated. When compared with reference value (1.5 mg/kg for Cr and 200 mg/kg for Mn), the highest accumulation by Cladophora fracta was seen in the month of June as 1442 ± 7.2% (23.13 mg/kg) for Cr and the lowest accumulation calculated in the month of July as 5 ± 0.2% (210 mg/kg) for Mn. In our study, the highest MPI value was 13.69 in September. The magnitude of MPI values of heavy metals determined during April to September appeared in the following order September > August > July > June > May > April. The HQing (hazard quotient due to ingestion) and HQinh (hazard quotient due to inhalation) in all months were chidren > female > male while the order of HQder (hazard quotient due to dermal) was determined as male > female > children. Non-carcinogenic risk (HQ) and Hazard Index (HI) values in terms of ingestion, inhalation and dermal ways were lower than 1. Also, total HI values were < 1. As a result, there was not non-carcinogenic and carcinogenic risks associated with usage of Cladophora fracta as mulch.
AtıfScopus4WoS4OpenAlex4İncele - MakaleAçık Erişim2020Scopus SJRQ2Fabrication of a novel acrylate polymer bearing chalcone and amide groups and investigation of its thermal and isoconversional kinetic analysis
Biryan, Fatih; Pihtili, Güzin
The aim of the article was to examine the thermal degradation, thermal decomposition kinetics and dielectric behavior of novel poly(APHP-Am–Ac). For this purpose, the novel monomer, 4-(3-(4-acetamidophenyl)-3-oxoprop-1-en-1-yl)phenyl acrylate (APHP-Am–Ac), was synthesized from 1-(4-aminophenyl)-3-(4-hydroxyphenyl) prop-2-en-1-one (APHP) and acetic anhydride reaction. The homopolymer P(APHP-Am–Ac) was prepared by free radical polymerization within dimethylformamide at 80 °C. The presence of rigid and bulky chalcone units in polymer side chains significantly improved the solubility of polyamides, giving them an amorphous nature and good thermal stability. The structural characterization of homopolymer was accomplished using FT-IR and NMR techniques. The thermal stability and degradation features of homopolymer have been performed by using TG analysis and FT-IR during partial degradation at different temperatures. The glass transition temperature of homopolymer was determined by DSC analysis. For thermal decomposition kinetics of poly(APHP-Am–Ac), Flynn–Wall–Ozawa and Kissinger methods were applied to thermogravimetric curves and apparent activation energies (Ea) calculated from these two methods. According to FWO, the activation energy (Ea) of the first step and the second step was found as: 157.78 kJ mol−1 and 151.81 kJ mol−1, respectively. For Kissinger’s model, Ea was calculated as 154.3 kJ mol−1 and 142.83 kJ mol−1, respectively. The dielectric and conductivity measurements of homopolymer were investigated by impedance analyzer technique in a range of 10 Hz–20 kHz frequency at different temperatures (from 25 to 120 °C). The results have been plotted as a function of frequency and temperatures. The values increased significantly with temperature.
AtıfScopus18WoS17OpenAlex18İncele - MakaleAçık Erişim2020Scopus SJRQ2Thermal studies and influence of the thermal decomposition on dielectric properties of a new coumarin copolymers
Biryan, Fatih; Pihtili, Güzin; Demirelli, Kadir
In this study, firstly 7-hydroxy-4-chloroethyl coumarin compound was synthesized in accordance with the literature (Peterson et al. in Macromol Chem Phys 202: 775–784, 2001). Then, this compound was reacted with acryloyl chloride to form the 4-(chloromethyl)-2-oxo-2H chromen-7-yl-acrylate) monomer. A series of copolymers were prepared using this monomer and n-butyl acrylate monomer. TGA analysis system was used to examine the thermal properties of homopolymers and copolymers. The activation energies were calculated for thermal decomposition of homopolymer and certain copolymers according to Flynn–Wall–Ozawa method. TGA measurements were taken at different heating rates and given comparatively. The glass transition temperatures of the copolymers were determined by DSC analysis and these results were given comparatively. For investigating the dielectric properties of copolymers, dielectric constant, dielectric loss factor, and ac conductivity values were calculated in the range of 100 Hz–20 kHz frequencies. The results were plotted as a function of frequency. In addition, dielectric behaviors of residues were determined after heating to the first decay temperature of the two-stage decay polymers and compared with the first states.
AtıfScopus6WoS6OpenAlex6İncele - MakaleYalnız künye2020Scopus SJRQ2The effect of graphene oxide on structural, opto-electrical and thermal properties of manganese sillenite (Bi12MnO20) nano-powders
Aydin, C.; Taskin, M.; Aydin, H.
In this study, manganese sillenite nano-powders were produced by hydrothermal method by adding graphene oxide in different mass amounts. Structural, morphological, thermal, optical and electrical properties of the obtained undoped and graphene-oxide-doped samples were investigated. XRD results showed that the produced samples had nano-sizes and the crystal sizes changed with the addition of graphene oxide. SEM and TEM images showed that the microstructures of the samples were nano-sized and composed of randomly oriented particles without orientation relationship between them. From FT-IR spectra of the samples, chemical properties and bond structures were determined. With the help of thermal analysis measurements, reactions in the sample structures at increasing temperatures, reaction temperatures, reaction energies and total mass losses were determined. The forbidden energy ranges of the samples decreased at significant rates with the addition of graphene oxide. By checking the P–E hysteresis cycles, the samples are understood to show ferroelectric properties. Dielectric measurements and temperature-dependent electrical conductivity measurements of the produced nano-powders confirmed that the samples exhibited semiconductor behaviour. The obtained results showed that manganese sillenites can be synthesised by low-temperature hydrothermal method and physical, chemical and thermal properties can be controlled by adding different amounts of graphene oxide for use in electronic and energy applications.
AtıfScopus6WoS6OpenAlex6İncele - MakaleYalnız künye2020Traces of late quaternary glaciations and paleoclimatic interpretation of Mount Akdağ (Alanya, 2451 m), Southwest Turkey
Bayrakdar, Cihan; Çılğın, Zeynel; Keserci, Ferhat
Mount Akdağ, located 25 km northeast of Alanya (2451 m above sea level a.s.l.), and largely made up of carbonates, is one of the mountains exposed to Late Quaternary glaciation in the Western Taurus Mountains. Although today, there are no modern glaciers, the traces of the Late Quaternary glaciers and rock glaciers are still fresh. In this study, geomorphological features related to the glaciations in Mount Akdağ, which were not previously reported in the literature, were first identified from satellite images, and then verified by field studies. The geomorphological development of Mount Akdağ during the Quaternary was explained by considering its climatic and karstic characteristics. For this purpose, spatial data obtained from field studies, unmanned aerial vehicles and meteorological stations were analysed using geographic information systems. Akdağ is directly open to humid air masses coming from the SW sector over the Mediterranean Sea, resulting in heavy orographic precipitation that encouraged the growth of glaciers. In addition, glacier reconstruction and pELA estimates have been made to contribute to the interpretation of glacial geomorphology. The pELA in Mount Akdağ was calculated with the AABR ratio of 1.69, and was found to be around 2030 m a.s.l. More than 15 cirques and a 6.5 km long glacial valley in Mount Akdağ indicate the presence of glaciers. Reconstruction of the paleoglaciers shows that the lowest altitude reached was 1410 m a.s.l. At their maximum extent glaciers covered an area of ~ 14 km2, with a volume of ~ 1 km3 and had an average thickness of 60 m with a maximum glacier thickness of ~ 200 m.
AtıfScopus19OpenAlex23İncele - MakaleAçık Erişim2020Scopus SJRQ2Variation with graphene oxide doping of structural, optical, dielectric and thermal properties of BaCO3:ZnO nanocrystals synthesized by solgel combustion method
Aydin, H.; Taskin, M.; Aydin, C.; Dagdelen, F.; Kaygili, O.; Bulut, N.; Orhan, A.
The results obtained from thermogravimetric (TG) analysis, X-ray diffraction analysis, optical characterization and dielectric measurements of the samples were investigated. In X-ray diffraction patterns, the presence of both BaCO3 and ZnO peaks showed that ZnO and BaCO3 nanocrystals were independently grown. Changes in the band peak position in the FTIR spectra showed that the chemical structure of Ba:Zn nanocomposites changed with the doping of graphene oxide. The optical band gap (Eg) of the samples was calculated as 3.18, 3.19, 3.2, 3.21 and 3.23 eV for BaZn, BaZn25, BaZn50, BaZn75 and BaZn100, respectively. It was determined that the dielectric constants and dielectric losses of the nanocomposites exhibited normal dielectric behavior, decreased with the frequency described in light of Maxwell–Wagner model and increased with increasing graphene oxide concentration. TG measurement showed that the mass loss in the sample decreased with increasing graphene oxide.
AtıfScopus4WoS4OpenAlex4İncele