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Design and performance analysis of a PV-assisted alkaline electrolysis for hydrogen production: An experimental and theoretical study
No full textThe PV assisted alkaline electrolysis cell was established for hydrogen generation. Lab-made AgNiCu modified nickel foam cathodes were used in this system. The characterization was achieved using field emission scanning electron microscopy, energy-dispersive X-ray and X-Ray diffraction analysis. The electrochemical performance was investigated via linear sweep voltammetry, cyclic voltammetry, Tafel polarization measurements and electrochemical impedance spectroscopy. The electrolysis potential and time depended efficiency was monitored. The structural theoretical analysis of the electrode surface and hydrogen evolution characteristics were also determined applying Density Functional Theory and Ab-initio Molecular Dynamics simulations which identified the role of Ag decoration and Cu incorporation on the surface against water and proton adsorptions. The modified cathode (AgNiCuF) improved the hydrogen production performance owing to lower hydrogen onset potential (-1.1 V) and charge transfer resistance (0.362 ohm at -1.5 V).Adana Alparslan Turkes University Research fund [23101001]; TUBITAK BIDEB 2209-A-University Students Research Projects Support Program [1919B012204108]; TUBITAK 3501 Career Development Program [120Z240]The authors are thankful to Adana Alparslan Turkes University Research fund for financial support (Project Number: 23101001) and TUBITAK BIDEB 2209-A-University Students Research Projects Support Program (Project Number: 1919B012204108) . Yeliz Gurdal would like to thank to TUBITAK 3501 Career Development Program (grant agreement No: 120Z240) . Molecular simulations were performed at the TUBITAK ULAKBIM, High Performance and Grid Computing Center (TRUBA) , based in Turkiye
Türkiye: The Implication of Iraq Conflict on the US-Türkiye Strategic Relationship
No full textThe main purpose of this article is to investigate the foundations of relations between T & uuml;rkiye and the US and to analyze the impact of the Iraq War on relations between the two countries. The relations that developed in the context of security after the Cold War were naturally supported by economic aid. Although there were many problems in the fragile relations during the Cold War, the ties between the two countries were never completely severed. While frequent occurrences strengthened T & uuml;rkiye's significance in the area, the divergent interests of the two nations have only recently begun to come into focus. The developments taking place in T & uuml;rkiye's neighboring countries also attract the attention of the United States, and the repercussions of events in these regions are reflected in T & uuml;rkiye, especially concerning conflicts involving Russia. In this context, although the relations between the two countries are often touted as an alliance, it highlights the fact that it leans more towards a necessity. At this point, the Iraq War has had a significant impact on the relations between the two countries and has led to the emergence and increase of problems between the two countries
Chitosan based injectable cryospheres as a potential biopolymeric carrier for drug delivery systems: Characterization, biocompatibility and drug release
No full textThree-dimensional scaffolds with the right design to support cell metabolism and the right physico-chemical, mechanical, and biological qualities have become more interesting for tissue engineering because of the complexity and diversity of the tissues involved. Moreover, three-dimensional scaffolds with tuneable drug delivery capabilities have drawn more attention in the field of soft tissue engineering. In this research, chitosanbased microspheres (called cryospheres) were fabricated in spherical shapes micron-sized with highly interconnected porous structures as a result of combining emulsification and cryogelation methods. The characterization of cryospheres was evaluated using morphological, physicochemical, and biological analyses. According to the results of the in vitro and in vivo biocompatibility investigation, the microspheres had no toxic effects on cell survival, and they even enhanced cell viability at the implantation site when compared to the control group. After the cryospheres were characterized, research was done on drug loading, drug release, and release processes using two distinct dyes (Nile Red: NR and Rhodamine-B: RB) in simulated body fluids (simulated intestinal, stomach, and tear fluids). The results showed that the maximum drug loading capacities for RB and NR were 89.32 +/- 1.57 % and 61.51 +/- 0.70 %, respectively. This study contributed to the development of minimally invasive biomaterials that have the potential to provide both drug release and tissue formation/regeneration at damaged implantation sites by carrying not only drugs but also active substances such as hormones/growth factors that will trigger new tissue formation.Mersin University Scientific Research Projects Unit [2018-1-TP3-2912]This study was carried out within the scope of the PhD program of the Chemical Engineering Department, Mersin University, Turkiye. It was financially supported by the Mersin University Scientific Research Projects Unit (2018-1-TP3-2912) . The authors would like to thank TUBITAK MAM for the implantation test
Examining the potential of peppermint essential oil-infused pectin and kappa-carrageenan composite films for sustainable food packaging
No full textEssential oils are key ingredients in the development of edible films and provide a diverse approach to improving food preservation, as well as sensory qualities. The pectin and kappacarrageenan composite films were obtained by adding peppermint essential oil in different quantities. The films after their fabrication were thoroughly evaluated for their attributes, which included mechanical, barrier, optical, chemical, thermal, and antioxidant properties. The visual assessment of the films demonstrated that PEO-loaded films showed a uniform, homogenous, and slightly yellowish appearance. There was an increase in the thickness (0.045 f 0.006 to 0.060 f 0.008 mm), elongation at break (12.73 f 0.74 to 25.05 f 1.33 %), and water vapor permeability (0.447 f 0.014 to 0.643 f 0.014 (g*mm)/(m2*h*kPa)) was observed with the addition of PEO. However, tensile strength (45.84 f 3.69 to 29.80 f 2.10 MPa) and moisture content (25.83 f 0.046 to 21.82 f 0.23 %) decreased with the incorporation of PEO. Furthermore, thermal and antioxidant properties were enhanced by the inclusion of PEO. The presented investigation can be employed to synthesize food packaging material with antioxidant properties with potential applications in food packaging.Deputyship for Research & Innovation, Ministry of Education in Saudi Arabia [ISP23-81]The authors extend their appreciation to the Deputyship for Research & Innovation, Ministry of Education in Saudi Arabia for this research work through the project number (ISP23-81)
Non-Detection of HCMV Total Genomic DNA in Human Glioma Cells Genome
No full textAIM: To demonstrate if the human cytomegalovirus (HCMV) genome, that is involved in the pathogenesis of gliomas, is part of the genomic DNA of glioma cells or not. MATERIAL and METHODS: The study included U87MG glioblastoma cell culture and tumor samples from glioma patients. The genomic DNA of tumor samples and U87MG cells were extracted and real-time quantitative PCR was used to assess the presence of the human cytomegalovirus genomic DNA. RESULTS: Consequently, HCMV positivity was not detected in the tumor and cell line genomic DNA under the aforementioned experimental conditions. CONCLUSION: We found that the genomic DNA of all the samples was negative for HCMV genomic DNA. Thus, HCMV could not be detected in human glioma tumors and we put forward that HCMV genomic DNA was not incorporated into the genomic DNA of glioma cells. Thus, total viral DNA is not involved in the pathogenesis of glioma; however, small viral particles or specific genes might be incorporated into the genomic DNA of glioma cells, leading to cancer development. This prompts further studies for verification.Scientific Research Projects Fund [MUHDBF.BYO.2014-5]The Scientific Research Projects Fund (Project number. MUHDBF.BYO.2014-5) provided funding for this work. The Federation of European Biochemical Societies (FEBS) Journal Special Issue for the 41 st FEBS Congress published the work's abstract as an oral presentation. Authors express their gratitude to Assoc. Prof. Seda Ceylan for her assistance in the transportation of some biological samples
Offset-fed Slotted Antenna Practically Loaded with Split Ring as Water Quality Sensor for X-Band Industrial Applications
No full textThis article describes the design, testing, and analysis of an offset-fed split ring-loaded slotted antenna for various water quality sensors. The antenna is designed to resonate at 10 GHz on a low-cost FR-4 substrate of dimensions 0.621?o×0.467?o×0.053?o, where ?o is the free space wavelength at the resonant frequency. The fabricated antenna finds excellent agreement with the measured antenna parameters. At 10 GHz, the antenna achieves a gain of 7.61 dBi, a nearly unidirectional radiation pattern, and a radiation efficiency of 76%. The research is further explored to use the antenna as a water sample sensor. The antenna is tested on various water samples by submerging it in them, and in the second scenario, contactless measurements at 10 mm away from the container's upper water level. The work examines the quality of the water by observing the shift in the resonant frequency (fr), the antenna quality factor with different total dissolved solvents (TDS) in the water samples, and changes in the reflection coefficient (S11) values. It is observed that the antenna shows less than 1.5% numerical sensitivity (NS) with fr, and high NS with the S11. The antenna's S11 and bandwidth vary and depending on the water sample. This antenna is suitable for X-band industrial and microwave laboratory applications. © 2024, Advanced Electromagnetics. All rights reserved
Model organızma galleria mellonella'da silikon dioksit nanopartikülleri ve çevresel kirleticilerin immünositotoksik ve antioksidan savunma sistemleri üzerindeki etkilerinin araştırılması
No full textLisansüstü Eğitim Enstitüsü, Biyomühendislik Ana Bilim Dalı, Biyomühendislik Bilim DalıBu çalışmada, Galleria mellonella son evre larvalarına SiO2 NP' lerinin LD50 değeri ile abamektin ve kadmiyum sülfatın (CdSO4) çevresel derişimlerinin tek başına ve karışım halinde uygulanması sonucunda hemolenf, orta bağırsak ve yağ dokuda superoksit dismutaz (SOD), katalaz (CAT), glutatyon peroksidaz (GPx), glutatyon-s-transferaz (GST), sitokrom P450 (Cyt P450), asetilkolinesteraz (AChE) enzim aktiviteleri ile diferansiyel ve total hemosit sayıları ve apoptotik indeks üzerine etkileri incelenmiştir. SiO2 NP' lerinin LD50 değeri, CdSO4 ve Abamektin ile tek başına ve karışım halinde uygulanması sonucunda, larvaların orta bağırsak ve yağ dokusunda antioksidan ve detoksifikasyon enzim aktivitelerinde doku farklılığına bağlı olarak değişiklikler meydana geldiği gözlemlenmiştir. Total hemosit sayısında, tek başına SiO2 NP, CdSO4 ve abamektin uygulaması sonucunda kontrol grubuna göre azalma meydana gelirken, SiO2 NP' lerinin CdSO4 ile karışım halinde uygulandığında artış, abamektin ile birlikte uygulandığında ise azalma meydana geldiği tespit edilmiştir. Diferansiyel hemosit sayıları üzerine etkilerinde ise, prohemosit, plazmatosit, sferülosit, granülosit ve önositoid sayılarında SiO2 NPs, CdSO4 ve Abamektinim tek başına ve karışım halinde uygulanan gruplarda artış ve azalışlar meydana geldiği gözlemlenmiştir. Bu çalışma sonucunda, SiO2 NPs, CdSO4 ve Abamektinin tek başına ve karışım halinde uygulanması sonucunda G. mellonella larvalarında toksik etkilere neden olduğu ve karışım uygulamaları sonucunda doku farklılıklarına bağlı olarak antioksidan savunma ve immun sistem üzerinde SiO2 NP'lerinin çevresel kirleticilerin toksik etkilerini artırabileceği belirlenmiştir.In the study, enzyme activities of superoxide dismustase (SOD), catalase (CAT), glutathione peroxidase (GPx), cytochorem P450 (Cyt P450), glutathione-s-transferase (GST), acetylcholinesterase (AChE) and total, differential haemocyte counts and apoptotic index were investigated in haemolymph, midgut and fat body of Galleria mellonella exposed to LD50 value of SiO2 NP, environmental concentration of abamectin and cadmium sulphate (CdSO4) singly and in mixture. Alterations in antioxidant and detoxification enzyme activities were observed in the midgut and fat body of G. mellonella larvae when exposed to SiO2 NP, abamectin and CdSO4 singly and in mixture.The total hemocyte count decreased in the SiO2 and CdSO4 singly applied groups however an increased were observed in the SiO2 NPs + CdSO4 mixture and a decreased were observed in the SiO2 NPs+abamectin group compared with the control. As for differential hemocyte counts, prohemocytes, plasmatocytes, spherulocytes, granulocytes, and oenocytoids was altered following treatment with SiO2 NPs, CdSO4, and abamectin sinlgly and in mixture. As a result of this study, it was determined that SiO2 NPs, CdSO4 and Abamectin lead to toxic effects in G. mellonella larvae as a result of single and mixture applications and it was also observed that SiO2 NPs may increase the toxic effects of environmental pollutants on antioxidant defence and immune system depending on tissue differences as a result of mixture applications
Investigation of the behavior of FRP reinforced steel fiber reinforced concrete beams
No full textLisansüstü Eğitim Enstitüsü, İnşaat Mühendisliği Ana Bilim DalıSunulan tezde, GFRP donatılı çelik lifli beton kirişlerin davranışı incelenmiştir. Çalışmada toplam beş adet kiriş numunesi üretilmiştir. Kiriş numuneleri 150×200 mm boyutlarında ve 2000 mm uzunluğundadır. Kirişlerden biri kontrol numunesi olarak normal beton ile üretilirken, diğer dört numune ise GFRP donatılı çelik lifli beton ile üretilmiştir. Hazırlanan kiriş numuneleri, yapısal davranışın belirlenmesi için dört nokta eğilme altında test edilmiştir. Deneysel çalışmada, çatlak yayılımları, yük-açıklık ortası deplasman ve yük-gerinim ilişkileri gözlemlenmiş ve kaydedilmiştir. Test edilen kirişlerin deneysel yük-deplasman diyagramları, kaydedilen deneysel yük ve karşılık gelen deplasman değerleri kullanılarak elde edilmiştir. Ayrıca, GFRP donatılı lifsiz ve çelik lifli beton kirişlerin yük-deplasman eğrilerini belirlemek için analitik bir yöntem sunulmuştur. Teorik çalışmada, lifsiz ve çelik lifli beton malzemenin doğrusal olmayan gerilme-şekil değiştirme davranışı dikkate alınmıştır. Kiriş numuneleri teorik yönteme göre analiz edilmiş ve sonuçlar test sonuçları ile karşılaştırılmıştır. Çalışmada deneysel ve teorik sonuçların iyi derecede uyum içinde oldukları belirlenmiştir. Çelik liflerin, GFRP donatılı lifsiz ve çelik lif beton kirişlerin yük-deplasman davranışını önemli ölçüde etkilediği sonucuna varılmıştır.In the presented thesis, the behavior of steel fiber reinforced concrete beams with GFRP bars has been examined. In the study, a total of five beam specimens were manufactured. The cross section sizes of beams were 150×200 mm and the beam specimens were 2000 mm in length. One beam was control specimen constructed with plain concrete, while the other four specimens were steel fiber reinforced concrete beams with GFRP bars. The prepared beam specimens were tested under four-point bending for the determination of the structural behavior. In the experimental study, the crack propagations, load versus mid-span deflections and load-strain relations were observed and recorded. The experimental load-deflection diagrams of the tested beams have been attained using recorded experimental load and corresponding deflection values. In addition, an analytical procedure has been presented to determine the load-deflection curves of plain and steel fiber reinforced concrete beams with GFRP bars. In the theoretical study, nonlinear stress-strain behavior of plain and steel fiber concrete material has been taken into account. The beam specimens were analysed based on the theoretical method and the results were compared with test results. A good degree of accuracy has been obtained between test and analysis results in the study. It is concluded that steel fibers considerably effect on the load-deflection behavior of plain and steel fiber reinforced concrete beams with GFRP bars
Yenilenebilir enerji kaynakları ve enerji depolama entegre sistemleri için çok portlu DC-DC dönüştürücü tasarımı ve modellemesi
No full textLisansüstü Eğitim Enstitüsü, Elektrik-Elektronik Mühendisliği Ana Bilim Dalı, Elektrik Elektronik Mühendisliği Bilim DalıBu tezde, yenilenebilir enerji sistemleri (YES), enerji depolama sistemleri ve yüklerin entegrasyonunu, birbirleri arasında optimum güç akışını mümkün kılan çok-portlu DA-DA dönüştürücü ve kontrol şemaları üzerine tasarım ve modelleme çalışmaları gerçekleştirilmiştir. Bu kapmsada, farklı dönüştürücü modelleri geliştirilmiş olup, YES ünitelerinde maksimum güç noktasının takibinin yapılabilmesi, enerji depolama ünitelerinde standartlara uygun şarj algoritmalarının uygulanabilmesi, yüklere kesintisiz güç sağlanabilmesi, ve çift yönlü güç akışının sağlanabilmesi amaçlanmıştır. Bu amaçlara yönelik olarak, tez kapsamında dört farklı çok-portlu DA-DA dönüştürücü topolojisi ve kontrolcüsü tasarlanmış ve modellenmiştir. Tasarım aşamasında topolojilerin matematiksel hesaplamaları gerçekleştirilmiş, kontrol şemaları ve anahtarlama durumları derinlemesine incelenmiş ve sunulmuştur. Önerilen dönüştürücüler, MATLAB/Simulink ve PSIM ortamlarında geliştirilmiş ve olası tüm güç akış senaryolarında sistem performansları test edilmiştir. Gerçekleştirilen performans inceleme çalışmaları neticesinde tasarımı gerçekleştirilen tüm dönüştürücü topoloji/kontrolcülerinin etkinliği ve uygulanabilirliği doğrulanmıştır.In this thesis, design and modeling studies have been conducted on multiport DC-DC converters and control schemes that enable the integration of renewable energy systems (RES), energy storage systems, and loads, allowing for optimal power flow between them. Within this scope, different converter models have been developed to achieve the following objectives: tracking the maximum power point in RES units, implementing standardized charging algorithms for energy storage units, providing uninterrupted power supply to the loads, and enabling bidirectional power flow. To achieve these objectives, four different multiport DC-DC converter topologies and their controllers have been designed and modeled in the thesis. During the design phase, the mathematical calculations of the topologies have been performed, and the control schemes and switching states have been thoroughly investigated and presented. The proposed converters have been developed in MATLAB/Simulink and PSIM environments, and their performance was tested in all possible power flow scenarios. Through the conducted performance analysis, the efficiency, and applicability of all designed converter topologies/controllers have been validated
GC-MS-Olfactometric characterization of key odorants in rainbow trout by the application of aroma extract dilution analysis: Understanding locational and seasonal effects
No full textThe effect of seasonal and regional differences of rainbow trout on its aroma and aroma-active profile was investigated. Solvent-assisted flavor evaporation (SAFE) procedure was employed for the aroma extraction while Gas Chromatography-Mass Spectrometry-Olfactometry (GC-MS-O) and aroma extract dilution analysis (AEDA) were utilized to assess the aroma-active substances. The olfactometric analysis indicated seasonal and regional differences in the aroma-active compounds contributing to the characteristic odours of the trout samples and the compounds were more intense in autumn and winter. The strongest aroma-actives were hexanal (green), acetoin (buttery, green), limonene (citrus), 2-hexanol (green, pungent) and 1-octen-3-ol (oily, mushroom). The findings of this study can provide useful information for the selection of rainbow trout based on the seasons and locations in terms of marketing and consumer preference.TUBITAK (The Scientific and Technological Research Institution of Turkey); [119O604]Acknowledgement We thank TUBITAK (The Scientific and Technological Research Institution of Turkey) for its financial support (Project number: 119O604) . We would also like to acknowledge the rainbow trout farm owners S?leyman Koksalan, Metin Kilincli and Osman Inceogullar? for their help for the supply of the fish samples used in this study