DSpace@ATÜ (Adana Alparslan Türkeş Bilim ve Teknoloji Universiti)
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Bacterial diversity and lysozyme activity of raw buffalo milk: a case study on milk collection tanks from selected farms
No full textApproximately 15% of the milk produced in the world comes from buffaloes. In this study, the microbiome and lysozyme activities of buffalo milk in the Tepecik region were investigated. Samples were taken from ten different farms and analyzed. The average lysozyme activities were 59.858 units x 10-3/mL. Taxonomic analyses showed that Lactococcus, Acinetobacter, Moraxella, Streptococcus, Anoxybacillus, Aeromonas generally constituted the dominant bacterial groups. Low lysozyme activities and Staphylococcus aureus and Micrococcus luteus values showed that the milk taken from ten farms was mastitis free. The presence of Acinetobacter, Moraxella, Anoxybacillus and Aeromonas bacteria, which pose a pathogenic risk for milk, indicates that proper sanitation of milking machines are required. Pseudomonas, a psychrophilic bacterium, was not detected in most products, but was detected in very small amounts in some products. This work sheds a light on future studies that covers lysozyme activity measurement combined with DNA sequencing for food safety in dairy industry.Kutahya Dumlupinar University Scientific Research Projects Unit [2024-05]; Dumlupinar Universitesi [2024-05]This work was supported by the Kutahya Dumlupinar University Scientific Research Projects Unit under Grant number 2024-05. Dumlupinar Universitesi [2024-05]
Integrated analytic hierarchy process and multi-criteria decision-making approach: An Application for Unmanned Underwater Vehicle Control Method Selection
No full textUsing Multi-Criteria Decision Analysis (MCDA) techniques, it is possible to thoroughly examine all available options and determine the most desirable ones. However, the prevalence of these methods, which employ various computational changes, can result in disparate outcomes. Therefore, the final rankings should be as dependable and consistent as possible. In this study, the consistency of the findings obtained from the TOPSIS, COPRAS, MAUT, and MOOSRA methodologies was investigated in the real-world problem of Unmanned Underwater Vehicle Control Method Selection by forming decision matrices through simulations
The facile production of Fe2O3-biochar electrocatalyst for methanol oxidation reaction
No full textIn this study, the facile-green method was applied for the production of electroactive composite anode material. For this purpose, biochar was produced via pyrolysis of Pinus nigra (PN) sawdust in a stainless-steel reactor at 300, 400 and 500 degrees C with 10 degrees C/min heating rate. The Fe2O3 particles were fabricated via the green synthesis method. The Fe2O3-biochar electrocatalyst was operated on Ni foam electrode and the potential application as an anode for methanol fuel cell was investigated in an alkaline medium. Field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), X-ray diffraction analysis (XRD), Brunauer-Emmett-Teller analysis (BET), and attenuated total reflectance Fourier transform infrared spectroscopy (FTIR/ATR) were used to characterize the morphology of the electrocatalyst samples. The electrochemical measurements of electrocatalyst samples were achieved via cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), linear sweep voltammetry (LSV) and chronoamperometry (CA). The enlarged surface area of biochar enabled the formation of more electroactive sites for methanol electrooxidation and favorable structures of biochar could support to increased electrocatalytic activity of catalysts for methanol oxidation and produce favorable matrices for Fe2O3 loading. The obtained results demonstrate that the electrooxidation of methanol occurred at 0.36 V. The favorable structures of biochar acted as a support, enhancing the electrocatalytic activity of Fe2O3 for methanol oxidation. The electrocatalyst demonstrated remarkable activity with almost 4 A g-1 current density at 0.55 V. The Rct values were 0.73 omega and 0.45 omega at 0.55 V, for Ni foam and Ni foam/Fe2O3-biochar, respectively. Long-term measurements demonstrated that the Ni foam/Fe2O3-biochar catalysts was remarkably stable, with a 4 % difference in current before and after the CA analysis.Karabuk University Co-ordination of Scientific Research Projects; [KBUBAP-23- YL-079]The authors are grateful for the support of Karabuk University Co-ordination of Scientific Research Projects (Project number: KBUBAP-23- YL-079
Challenges and Recovery Opportunities in Waste Management During the Mining and Enrichment Processes of Rare Earth Elements Containing Ores
No full textWaste management strategies in mining processes are shaped according to the characteristics of the operating process, the type of ore, and the existing socio-environmental conditions. The implementation of the budget and improvement programs required by the waste management plan is determined by the way these issues are taken into account during planning. Various harmful wastes and some recyclable residues are generated during the recovery of rare earth element(s) (REE) and other elements from ores containing REE. Mining and ore preparation process residues, that is, waste and tailings, pose various waste management problems. In this study, the characteristics of waste and tailings resulting from mining and ore preparation activities of REEs were explained, the difficulties encountered were mentioned, and solution suggestions were presented by making use of the literature on REE recovery from tailings and waste management. REEs can be found secondarily with other minerals. Recovery of REEs and other valuable elements from stored mineral waste piles may be possible in the future. In this way, countries that make strategic plans for REE or have reserves will be able to conduct new project studies and investments regarding waste containing REE. In this study, opportunities and challenges in the recovery of REEs from mining tailings, their environmental impacts, and waste management were reviewed. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2024
Unravelling tourism destination's competitiveness using big data analytics: a comparative analysis
No full textPurposeThe competitiveness of destinations is crucial for tourism. In this context, the study aims to uncover customer satisfaction, experiences, feelings, and thoughts by conducting a comparative analysis of social media comments from various competitive tourism destinations.Design/methodology/approachBig data research was conducted to answer the research questions. The data was collected on a social media platform focusing on three destinations in the Mediterranean region. Three methods were employed to analyse the data: sentiment analysis, topic modelling, and named-entity recognition.FindingsThis study addressed traveller satisfaction levels. It identified the topics concerning each destination, examined the emotions expressed by travellers about these topics, explored the potential impact on future behaviour, and investigated the features of the destinations and satisfaction levels about these features. It also identified the prominent food and beverage names in destinations and explored tourists' preferences regarding these foods and beverages.Research limitations/implicationsThe limitations of this study relate to the sample. The data used in this study was solely obtained from a single social media platform and focused on English-only comments. Further research that includes different social media platforms for hotel categories and considers reviews in local languages could capture a broader range of customer opinions and experiences.Practical implicationsPolicymakers can gain insight into a destination's position in the competitive landscape. This study has numerous implications for policymakers in the relevant destinations and managers in the design and implementation of services.Social implicationsThe findings of this study can have broader societal implications if considered and implemented by decision-makers and tourism businesses in the context of competitiveness.Originality/valueThe study's originality lies in integrating multiple disciplines and comparing tourism destinations using big data. This study improves the understanding of competitiveness in three specific Mediterranean destinations. Previous research has focused on different contexts in these Mediterranean destinations. Therefore, the study fills this gap by focusing simultaneously on all three destinations in the context of competitiveness
Energy Management in Organized Industrial Zones: Promoting the Green Energy Transition in Turkish Manufacturing Industry
No full text20th International Conference on the European Energy Market (EEM) -- JUN 10-12, 2024 -- Istanbul, TURKEYOrganized Industrial Zones (OIZ), which gained legal status by Law 4562 of 2000, played a significant role in Turkish industrialization policies, particularly in improving Small and Medium-sized Enterprises (SMEs). The energy management (EM) within OIZs is essential for Turkiye's green transition and 2053 net-zero pathway. Following the publication of a directive on OIZ's electricity market activities in 2006, enterprises can purchase electricity directly from OIZ management. Moreover, the Energy Efficiency Law No. 5627 of 2007 required OIZs to establish an energy management unit (EMU) to serve the participants with less than 1000 tons of oil equivalent (toe) energy consumption. EMUs provide OIZ management with a unique opportunity to enhance sustainable energy transition by increasing renewable energy production and improving the energy efficiency of participating enterprises. The primary goal of this research is to evaluate the effectiveness of energy management units in OIZs in encouraging energy efficiency and green energy transition in the Turkish manufacturing industry. As a case study, we examine EM in the Adana Haci Sabanci Organized Industrial Zone (Adana OIZ), which ranks third among OIZs regarding electricity consumption. We analyze data on electricity infrastructures, roof-top PVs, invoice settlements/offsets, energy efficiency investments, and GHG emissions between 2017 and 2023. Our preliminary findings suggest that EMU in the Adana OIZ makes a very important contribution to the green transition of industrial establishments and that regulatory changes over the last decades have had positive effects. The share of renewable energy in the total energy mix increased from 1.6% to 21.4% over six years, and there has been a noteworthy enhancement in energy efficiency, reaching 27% in 22 companies evaluated. The main policy implication of our findings is that the role of regulatory bodies and efficient energy management in OIZs will be critical in achieving Turkiye's net zero target of 2053.IEEE,Kadir Has Univ, Ctr Energy & Sustainable Dev,Senkron Energy Digital Serv,IEEE Turkiye Sect,IEEE Power & Energy SocTUBITAK (The Scientific and Technological Research Council of Turkiye) [122M210]; Developing Circular Economy and Industrial Symbiosis for Transforming Adana Haci Sabanci Organized Industrial Zone into an Eco-Industrial Park; Adana Haci Sabanci Organized Industrial Zone firms; Dokuz Eylul University; Izmir Institute of TechnologyThe authors thank TUBITAK (The Scientific and Technological Research Council of Turkiye) for supporting the project no. 122M210 entitled Developing Circular Economy and Industrial Symbiosis for Transforming Adana Haci Sabanci Organized Industrial Zone into an Eco-Industrial Park to Comply with the European Green Deal. Our thanks are also due to the Regional Directorate, Project Support Office, and the Adana Haci Sabanci Organized Industrial Zone firms for their continued support of the project. Our thanks are also due to project assistants Gulper Basmaci Aktuna, Ph.D. candidate, Dokuz Eylul University, Berat Batuhan Kaplangi, M.Sc. candidate, Izmir Institute of Technology, Melisa Tugcu, M.Sc. candidate Kadir Has University, and Sedanur Ozdamar, undergraduate student, Kadir Has University for their help in compiling references and writing texts
A new application of avocado oil to enrich the biological activities of polycaprolactone membranes for tissue engineering
No full textThe metabolites synthesized by plants to protect themselves serves as natural antimicrobial agents used in biomaterials. In this study, avocado oil (AO), was incorporated as a plant source and natural antimicrobial agent into polycaprolactone (PCL) membranes. The effects of varying AO ratios (25, 50, and 100 wt%.-PCL@25AO, PCL@50AO, PCL@100AO) on PCL membrane morphology, chemical structure, wettability, antimicrobial activity, and cell viabilities were investigated. It was demonstrated that the AO acts as a pore-forming agent in solvent-casted membranes. Young's modulus of the membranes varied between 602.68 and 31.92 MPa and more flexible membranes were obtained with increasing AO content. Inhibition zones of AO were recorded between 7.86 and 13.97 mm against clinically relevant microbial strains including bacteria, yeast, and fungi. Antimicrobial activity of AO was retained in PCL membranes at all ratios. Resazurin assay indicated that PCL@25AO membranes were cytocompatible with mouse fibroblast cells (L929 cell line) on day 6 showing 72.4% cell viability with respect to neat PCL membranes. Viability results were supported by scanning electron microscopy images and DAPI staining. The overall results of this study highlight the potential of PCL@25AO membranes as a biomaterial with antimicrobial properties, cytocompatibility, and mechanical strength suitable for various biomedical applications. imageThe Scientific and Technological Research Council of Tuerkiye [TUBITAK 2209A/1919B012003953]The authors thank to The Scientific and Technological Research Council of Tuerkiye (TUBITAK 2209A/1919B012003953) for the funding
Tarımsal sulama için IoT tabanlı pompa performansının izlenmesi ve makine öğrenimi modelleri ile kestirimci bakımın tahminlenmesi
No full textLisansüstü Eğitim Enstitüsü, Elektrik-Elektronik Mühendisliği Ana Bilim DalıKırsal alanlarda tarım sulamaları için sulama pompaları kullanılmaktadır. Kırsal tarım alanında bulunan sulama pompalarının periyodik bakımı maliyetli ve zaman alıcıdır; gerçek zamanlı bilgi alınmasıyla sorunların önceden tespit edilmesi, maliyet ve zaman kayıplarını önler. Bu çalışmanın temel amacı, Nesnelerin İnternetini (IoT) kullanarak tarımsal sulama için kurulan pompanın performansını anlık olarak izlemek ve sistem verilerine regresyon modelleri uygulayıp genetik algoritma (GA) ile modeller için optimum parametre değerlerini sağlamaktır. İlk olarak otomasyon sistemi kurularak sıcaklık, nem, akım, gerilim ve pompa titreşim bilgileri "Thingspeak" adlı bir IoT platformuna aktarılmıştır. Ardından Qt kullanıcı arayüzü oluşturma araç seti ile bir uygulama oluşturulmuştur. Bu uygulama sayesinde sistemde meydana gelen arızalar anlık olarak kullanıcıya bildirilmiştir. Sistemin kestirimci bakımı, makine öğrenimi alanında iki aşamalı bir süreçten oluşmaktadır. İlk aşamada, dört farklı yöntem modeli değerlendirildi. Bu modeller doğrusal regresyon, polinom regresyon (PR), rastgele orman regresyonu (RFR) ve destek vektör regresyonudur (SVR). İkinci aşamada, GA kullanılarak PR, SVR ve RFR modellerinin en uygun parametreleri belirlendi. Sonuç olarak, veri seti için en uygun modelin rastgele orman regresyon modeli olduğu bulunmuştur. Bu tezin, tarımsal sulama için IoT tabanlı pompa performansı izleme ve makine öğrenimi modelleri kullanarak kestirimci bakım tahmini ile ilgilenen araştırmacılara katkı sağlayacağı umulmaktadır.Irrigation pumps are used for agricultural irrigation in rural areas. Periodic maintenance of irrigation pumps in rural agricultural areas is costly and time-consuming; early detection of problems with real-time information avoids cost and time loss. The main objective of this study is to monitor the performance of the pump installed for agricultural irrigation using the Internet of Things (IoT) and to apply regression models to the system data and to provide the optimum parameter values for the models with genetic algorithm (GA). Firstly, the automation system was installed and the temperature, humidity, current, voltage and pump vibration data were transferred to an IoT platform the named "Thingspeak". Then, an application was created with the Qt user interface creation toolkit. Thanks to this application, malfunctions occurring in the system were instantly notified to the user. Predictive maintenance of the system consists of a two-stage process in the field of machine learning. In the first stage, four different method models were evaluated. These models are linear regression, polynomial regression (PR), random forest regression (RFR) and support vector regression (SVR). In the second stage, the optimal parameters of PR, SVR and RFR models were determined using GA. As a result, the random forest regression model was found to be the most appropriate model for the dataset. It is hoped that this thesis will contribute to researchers interested in IoT-based pump performance monitoring for agricultural irrigation and predictive maintenance estimation using machine learning models
The Level of Cash Holdings and Financial Performance: Evidence from Firms Listed on Borsa Istanbul 50 Index
No full textCash is of great importance to firms operating in emerging economies. Cash, one of the most important assets, creates shareholder value when rationally used by firm management. This paper aims to reveal the relationship between financial performance and cash holdings by using a sample that consists of non-financial firms listed in Borsa Istanbul 50 index. The result of empirical analysis provides strong evidence that financial performance is positively influenced by cash holdings. Further, firm size, capital intensity ratio and current ratio did not significantly influence the financial performance of sample firms, while financial performance of sample firms is significantly influenced sales growth and financial leverage. Overall, the research findings indicate that firm-specific factors are important factors that affect the relationship between financial performance and cash holdings. The present paper provides important insights for creditors, shareholders and firm management on the impacts of cash holding levels on financial performance
Tamamen kendinden korumalı dağıtım trafosu tasarımı ve uygulaması
No full textLisansüstü Eğitim Enstitüsü, Elektrik ve Elektronik Mühendisliği Ana Bilim DalıGeleneksel dağıtım transformatörlerinde, sistemin korunması için ayırıcılar, kesiciler, parafudrlar, ölçüm panosu gibi ek donanımlar harici olarak monte edilmektedir. Kullanılacak transformatörlerin tipi, koruma elemanları ve diğer ek donanımlar ülkeden ülkeye değişiklik göstermektedir. Amerika, Meksika ve Hindistan gibi kimi ülkelerde elektrik enerjisi dağıtımının bir kısmı, ilk yatırım maliyeti düşüklüğü, daha esnek işletme koşulları, hızlı devreye alma gibi sağladığı avantajlar nedeniyle tamamen kendinden korumalı (CSP) transformatörler ile gerçekleştirilmektedir. CSP transformatörler, geleneksel transformatörlerde karşılaşılabilen bakım ve işletme problemleriyle karşılaşılmayan elektrik makineleridir. Bu transformatörler sekonder kısa devrelerden, yıldırım darbesinden, aşırı yüklenmelerden kendi kendini koruyabilmekte ve aşırı yüklenme durumu hakkında görsel uyarı verebilmektedirler. Bu makineler ayrıca arıza durumunda kendisini sistemden izole ederek bağlı olduğu dağıtım sistemini de korumaktadırlar. Bu tezde, 500 kVA, 33/0.4 kV CSP transformatörün tasarımı ve geliştirilmesi ele alınmıştır. Transformatörün elektriksel, termal, mekanik tasarımı detaylı olarak sunulmuş ve malzeme/ekipman seçimleri tasarım parametreleri hesaba katılarak tamamlanmıştır. Performans testleri aracılığıyla geliştirilen ürünün tatmin edici şekilde çalıştığı gözlemlenmiş ve deneysel doğrulaması yapılmıştır. Bu tez ile, CSP transformatörler ile ilgili literatüre katkı sağlayarak araştırmacılara ve transformatör üreticilerine ışık tutulması hedeflenmektedir.In traditional distribution transformers, additional equipment such as separators, breakers, surge arresters and measurement panels are mounted externally to protect the system. The type of transformers, protection elements and other additional equipment to be used vary from country to country. In some countries such as America, Mexico and India, some of the electrical energy distribution is carried out with completely self-protected (CSP) transformers due to the advantages they provide such as low initial investment cost, more flexible operating conditions and rapid commissioning. CSP transformers are electrical machines that do not encounter the maintenance and operating problems that can be encountered in traditional transformers. These transformers can protect themselves from secondary short circuits, lightning strikes, overloads and provide visual warnings about overload conditions. These machines also protect the distribution system to which they are connected by isolating themselves from the system in case of malfunction. In this thesis, the design and development of 500 kVA, 33/0.4 kV CSP transformer is discussed. The electrical, thermal and mechanical design of the transformer is presented in detail and material/equipment selections are completed taking into account the design parameters. It has been observed that the developed product works satisfactorily through performance tests and its experimental verification has been made. With this thesis, it is aimed to shed light on researchers and transformer manufacturers by contributing to the literature on CSP transformers