DSpace@ATÜ (Adana Alparslan Türkeş Bilim ve Teknoloji Universiti)
Not a member yet
3463 research outputs found
Sort by
Drenaj Alan-Oran Yönteminin Seyhan Havzası Akımlarına Uygulanması ve Sonuçların Kontur Grafikleri ile Değerlendirilmesi
No full textSu kaynakları mühendisliğinin temelini hidrolojik çalışmalar oluşturmaktadır. Özellikle su yapılarının tasarımı süreçlerinde veri analizleri önemli bir yer tutmaktadır. İyi bir planlama aşaması gözlemlenmiş akım verilerinin eksiksiz olması ile doğrudan bağlantılıdır. Ancak birçok sebepten ötürü debi ölçümlerinin tam olamadığı bir gerçektir. Dolayısı ile eksik olan verilerin uygun metotlarla tamamlanması su mühendisliği çalışmalarının yönetimsel süreçleri açısından kaçınılmazdır. Bu çalışmada Drenaj Alan-Oran (DAR) metodunun söz konusu eksik verilerin tamamlanabilmesi amacıyla Seyhan Havzası akımlarına uygulanması noktasında değerlendirmeler yapılmıştır. Havzadaki altı farklı gözlem istasyonu arasında ve aynı akış güzergahında yer alacak şekilde veri transferleri gerçekleştirilmiştir. Taşınan veriler ile o noktadaki ham verilerin arasındaki korelasyon sonuçları irdelenmiştir. Ayrıca literatürde yer alan Yanlılık Düzeltmesi ile uygun bir katsayı belirlenmiş, düzeltilmiş verilerle birlikte kontur grafikleri oluşturulmuştur. Çalışma sonucunda taşınıp düzeltilmiş tüm istasyon verileri için kabul edilebilir bir düzeyde belirlilik katsayı değerleri elde edilmiştir. 1829 nolu istasyon akım değerlerinin 1830 nolu istasyona transferi ile ham debilere oldukça yüksek oranda bir yakınsama gerçekleştiği gözlemlenmiştir. Bu verilerin taşınımında determinasyon katsayısı 0,956 olarak hesaplanmış, dolayısı ile çalışmadaki en yüksek performans değeri ortaya çıkmıştır. Ayrıca pik debilerin düzeltme katsayısıyla bir miktar azaldığı ve ham debilere yaklaştığı tespit edilmiştir
Assessment of Hydrological Drought Index change over long period (1990-2020): The case of Iskenderun Gonencay Stream, Turkiye
No full textRecently, due to changes in the global climate, there have been significant increases in flood and drought events. The changes in wet and dry periods can be examined by various methods using hydrometeorological data to analyze climate disasters. In this study, Gonencay Stream in the Asi River Basin was chosen as the study area, which contains abundant underground and surface water reserves in Turkiye. Within this region, not only are the agricultural activities intense, but also hydraulic structure applications such as dams and reservoirs draw attention. Previous studies stated that meteorological and agricultural droughts have started to be noticed in the basin. Therefore, temporal variation analyses can positively contribute to assessing possible hydrological droughts in the following years. In this context, wet and drought periods were determined using the Streamflow Drought Index method at 3, 6, 9, and 12-month time scales with monthly average flow data observed between 1990 and 2020. At the same time, the number and probabilities of drought categories on a 12-month time scale, the first expected transition times between classifications, and the expected residence times between categories were specified. The study revealed that the most severe dry period occurred between 2013 and 2014 and was classified as Extremely Drought. The wettest period was around 2018-2019 and was classified as Extremely Wet. The largest expected time residence among all classifications was calculated for the Extremely Drought category with nine months, means that if the Extremely Drought period ever occurs, it remains for approximately nine months. While the Moderately Drought period occurred within one month following the Extremely Drought duration, and a Near Normal Wet period was observed three months after the Extremely Wet period. The most seen drought category for monthly calculations was the Near Normal Wet category, and was seen over 200 times with a 52.8% probability. Considering the Gonencay region, it is possible that any Extreme drought classification eventually regresses to normal
The role of preschool education in the integration process of children from the perspective of Syrian families: The case of Iskenderun
No full textLisansüstü Eğitim Enstitüsü, Kent Çalışmaları Ana Bilim Dalı, Kent Çalışmaları Bilim DalıBu çalışmada İskenderun'da yaşayan Suriyeli ailelerin çocuklarının topluma entegrasyon sürecindeki okul öncesi eğitimin etkisi araştırılmıştır. Araştırma konusu 'Suriyeli Ailelerin Bakış Açısından Çocuklarının Entegrasyonu Sürecinde Okul Öncesi Eğitimin Rolü: İskenderun Örneği şeklinde belirlenmiştir. Göç ve sonrasında karşılaşılan entegrasyon sürecinde okul öncesi eğitimin rolünü incelemek için alt başlıklar halinde detaylı alan yazın taramasına başvurulmuştur. Kavramsal olarak göç ve çeşitlerine, göç ve hukuki statüsüne, zorunlu yapılan göçlerin doğurduğu sonuçlara, göç sonrası eğitim süreçlerine, okul öncesi dönemde karşılaşılan problem davranışlara, Suriyeli çocukların okul öncesi eğitime uyum sürecine, eğitim engellerine, Suriyeli öğrencilerin devlet okullarındaki öğrenci sayılarına detaylı olarak değinilmiştir. Araştırmanın çalışma grubunu Hatay İskenderun ilçesinde bulunan devlete bağlı ilkokul anasınıflarında ve anaokullarında eğitim gören Suriyeli öğrencilerin velileri oluşturmaktadır. 10 farklı okuldan toplamda 30 veli katılımı ile nitel araştırma yöntemleri kullanılarak veriler elde edilmiştir. Araştırmanın verileri araştırma sorusu ışığında hazırlanmış yarı yapılandırılmış görüşme formu ile elde edilmiştir. Bu kapsamda; öncelikle Suriyeli ailelerin bakış açısından çocuklarının okul öncesi eğitim aracılığıyla entegrasyon süreci araştırılmıştır. Okul öncesinde ve okula başladıktan sonra ne tür değişimler yaşandığı, dil problemi karşısında okulun rolü, yeni kültürel yapıya alışma ve topluma uyum sağlamada okul öncesi eğitimin önemi aileler tarafından yorumlanmıştır. Araştırma sonunda literatür taraması ve Suriyeli ailelerin bakış açısıyla elde edilen bulgularda; çocukların entegrasyonunda okul öncesi eğitimin olumlu yönde katkıları olduğu saptanmıştır. Suriyeli aileler görüşmeler sırasında; entegrasyonu zorlaştıran ve en sık karşılaşılan sorunun dil bilmemek olduğunu belirtmişlerdir. Çalışmaya katılan Suriyeli aileler, okul öncesi eğitimin çocuklarının kısa zamanda Türkçeyi öğrenmesine olumlu katkıları olduğunu ifade etmişlerdir. Bu noktada katılımcılar; okul öncesi eğitim sürecinde Türkçe öğrenen çocuktan anne babaların da bazı kelimeleri öğrendiklerini belirtmişlerdir. Okulda öğretmenle ya da sosyal hayatlarında Türk vatandaşlarıyla iletişim kurarken Türkçeyi öğrenen okul öncesi çağı çocuklarından yardım aldıklarını da yapılan görüşmeler kapsamında aktarmışlardır. Sonuç olarak; tezde okul öncesi eğitimin çocuğun entegrasyon sürecindeki rolü araştırılmıştır. Bu sürecin çocukların topluma entegrasyonuna olumlu katkı sağladığını ortaya koyabilmek amaçlanmıştır. Anahtar Kelimeler: Suriyeli öğrenciler, entegrasyon, okul öncesi eğitimin önemiIn this study, the effect of preschool education of Syrian children in the process of integration into society was investigated. The research topic was determined as 'The Role of Preschool Education in the Integration Process of Children from Syrian Families from the Perspective of Syrian Families: İskenderun Example'. A detailed literature review was conducted under subheadings to examine the role of preschool education in the integration process encountered after migration. Conceptually, migration and its types, the legal status of the migration, consequences of forced migrations, post-migration education processes, problem behaviors encountered in the preschool period, adaptation process of Syrian children to preschool education, educational barriers, and detailed information about the number of Syrian students in state schools were discussed. The study group of the research consists of the parents of Syrian students who receive education in state-affiliated preschool classes and kindergartens in Hatay İskenderun district. Data were obtained using qualitative research methods with a total of 30 parents participating from 10 different schools. The data of the research were obtained with a semi-structured interview form prepared in the light of the research question. In this context; firstly, the integration process of children through preschool education from the perspective of Syrian families was investigated. What kind of changes were experienced before and after preschool and school, the role of school in the face of language problems, and the importance of preschool education in adapting to the new cultural structure and integrating into society were interpreted by families. At the end of the research, it was determined that preschool education has positive contributions to children's integration in the findings obtained from the literature review and Syrian families' perspectives. Syrian families stated during the interviews that not knowing the language is the most common problem that makes integration difficult. The Syrian families who participated in the study stated that preschool education has positive contributions to their children's learning of Turkish in a short time. At this point, the participants stated that parents also learned some words from their children who learned Turkish during the preschool education process. As a result; In this thesis, the role of preschool education in the child's integration process was investigated. It is aimed to reveal that this process contributes positively to the integration of children into society. Keywords: Syrian students, integration, importance of preschool educatio
Exploiting Digitalization of Solar PV Plants Using Machine Learning: Digital Twin Concept for Operation
No full textThe rapid development of digital technologies and solutions is disrupting the energy sector. In this regard, digitalization is a facilitator and enabler for integrating renewable energies, management and operation. Among these, advanced monitoring techniques and artificial intelligence may be applied in solar PV plants to improve their operation and efficiency and detect potential malfunctions at an early stage. This paper proposes a Digital Twin DT concept, mainly focused on O&M, to obtain more information about the system by using several artificial intelligence boxes. Furthermore, it includes the development of several machine learning (ML) algorithms capable of reproducing the expected behavior of the solar PV plant and detecting the malfunctioning of different components. In this regard, this allows for reducing downtime and optimizing asset management. In this paper, different ML techniques are used and compared to optimize the selected methods for enhanced response. The paper presents all stages of the developed Digital Twin, including ML model development with an accuracy of 98.3% of the whole DT, and finally, a communication and visualization platform. The different responses and comparisons have been made using a model based on MATLAB/Simulink using different cases and system conditions. © 2023 by the authors
Turkey's Green Economy Initiative: An Experimental Evaluation of Hydrogen Energy
No full textGreen economy is a concept that aims to achieve sustainable economic growth without harming the environment. Reducing carbon footprint is an important tool for the green economy. The contribution of reducing carbon footprint to the green economy is to measure the impact of economic activities on the environment and guide the development of green economy practices. Through green economy practices, carbon footprint can be reduced, environmentally friendly production and consumption habits can be promoted, and natural resources can be used more efficiently. Turkey is in a moderate position in terms of carbon footprint worldwide. As of 2019, Turkey's carbon footprint was calculated as 370 million tons of carbon dioxide (CO2) equivalent. The energy sector, industrial activities, transportation and agriculture sectors are among the largest sources of carbon footprint in Turkey. In this study, the evaluation of hydrogen gas production for reducing carbon footprint during Turkey's transition to the green economy is discussed. The production and evaluation of the cathode electrode used in hydrogen gas production with the alkaline electrolysis system were conducted. For this purpose, a novel, cheap and accessible cathode material containing transition metal was used for the first time in the literature, which was produced by a triple coating of nickel (Ni), iron (Fe), and molybdenum (Mo) on a nickel foam electrode surface at different potentials (2.1 V - 3 V) and different times (5-30 minutes) with two electrode techniques to produce hydrogen gas. According to the results, the amount of hydrogen gas produced per unit surface area (m2) of the electrode during a 30-minute period was approximately 516 L, and the energy value determined by the Lower Heating Value (LHV) was 5533.2 kJ/kg H2
Vibration analysis of sandwich cylindrical shells made of graphene platelet polymer-viscoelastic-ceramic/metal FG layers
No full textIn this paper, natural frequencies and loss factors of cylindrical sandwich shells composed of the viscoelastic core layer, surrounded by functionally graded graphene-platelet reinforced polymer composite (FG-GPLRPC) and ceramic/metal (FG-ceramic/metal) are investigated. The viscoelastic layer is modeled via the fourth parameter fractional viscoelastic pattern, and the functionally graded ceramic/metal layer is theoretically modeled using a power-law function. The uniform, symmetric and un-symmetric patterns are considered for simulating the graphene platelet (GPL) nanofillers distributions along with the thickness direction. The classical shell theory is used for functionally graded layers and properties of the effective materials of GPLRPC multilayers are determined by using a modified Halpin-Tsai micromechanics model and the rule of mixture. The governing equations of motion are extracted by applying the Lagrange equation and the Rayleigh-Ritz method. The determinant of the coefficient matrix of the characteristic equation is calculated, and the natural frequencies and loss factors of the system are extracted. A study of the interactions of materials and geometrical factors such as the ratio of radius to length, the properties of functionally graded materials, and GPL weight fractions for patterns of proposed distributions are presented and some conclusions have been formed
A novel multi-head CNN design to identify plant diseases using the fusion of RGB images
No full textPlant diseases and insect pests cause a significant threat to agricultural production. Early detection and diagnosis of these diseases are critical and can reduce economic losses. The recent development of deep learning (DL) benefits various fields, such as image processing, remote sensing, medical diagnosis, and agriculture. This work proposed a novel approach based on DL for plant disease detection by fusing RGB and segmented images. A multi-headed DenseNet-based architecture was developed, considering two images as input. We evaluated the model on a public dataset, PlantVillage, consisting of 54183 images with 38 classes. The fivefold cross-validation technique achieved an average accuracy, recall, precision, and f1-score of 98.17%, 98.17%, 98.16%, and 98.12%, respectively. The proposed approach can distinguish various plant diseases with different characteristics by image fusion. The high success rate with low standard deviation proves the robustness of the model, and the model can be integrated into plant disease detection and early warning system
Bond performance of geopolymer concrete via hinged beam approach
No full textLisansüstü Eğitim Enstitüsü, İnşaat Mühendisliği Ana Bilim Dalı, İnşaat Mühendisliği Bilim DalıBu tez çalışmasının amacı, geopolimer betonun çelik ile aderans davranışının, geleneksel portland çimentolu beton ile karşılaştırılmasıdır. Çelik-beton aderans davranışı, betonarme sistemlerin temel parametrelerinden biri olup, literatürde, geopolimer betonun aderans davranışı ve yapısal performansı hakkında sınırlı sayıda çalışma bulunmaktadır. Araştırmanın ilk aşamasında, alüminosilikat kaynağı olarak uçucu kül kullanılarak, 1,1, 1,2, 1,3, 1,4 Ms Modülü (Silika Modülü) değerine sahip geopolimer betonlar üretilmiştir. Tasarımında %10 sabit Na2O konsantrasyonu tercih edilmiş ve 80, 100, 120 °C sıcaklıklarda ısıl kür uygulanmıştır. Bu betonların taze haldeki işlenebilirliği ve sertleşmiş haldeki basınç dayanımları incelenmiştir. İkinci aşamada, aderans performansı mafsallı kiriş yöntemiyle analiz edilmiştir. Geopolimer beton ve geleneksel portland çimentolu beton kullanılarak, 5Ø, 10Ø ve 20Ø kenetlenme boyuna sahip kirişler üretilmiş ve bu amaçla her iki beton tipinin eğilme durumunda aderans performansı göreceli olarak karşılaştırılmıştır. Sonuç olarak, geopolimer betonun aderans performansının, benzer dayanıma sahip geleneksel portland çimentolu betona göre üstün olduğu belirlenmiştir. Anahtar Kelimeler: geopolimer beton, geleneksel portland çimentolu beton, aderans, mafsallı kiriş deneyiThe purpose of this thesis work is to compare the bond behavior of geopolymer concrete with steel to that of traditional Portland cement concrete. The steel-concrete bond behavior is one of the fundamental parameters of reinforced concrete systems, and in the literature, there are a limited number of studies on the bond behavior and structural performance of geopolymer concrete. In the initial stage of the research, geopolymer concretes with Ms (Silica Module) values of 1.1, 1.2, 1.3, and 1.4 were produced using fly ash as an aluminosilicate source. A constant Na2O concentration of 10% was preferred in the design, and heat curing was applied at temperatures of 80, 100, and 120°C. The workability of these concretes in their fresh state and their compressive strengths in their hardened state were examined. In the second stage, the bond performance was analyzed using the Standard Belgium Hinged Beam method. Beams with diameters of 5Ø, 10Ø, and 20Ø were produced using geopolymer concrete and traditional Portland cement concrete, and for this purpose, the bond performance of both types of concrete in bending conditions was comparatively assessed. As a result, it was determined that the bond performance of geopolymer concrete is superior to traditional Portland cement concrete with similar strength. Keywords: geopolymer concrete, conventional portland cement concrete, bond peformance, hinged beam tes
Electrospun TiO2 Nanofibers in the Presence of Avocado Seed Extract
No full textThe electrospinning technique is particularly prominent in membrane production techniques due to its easy applicability and ability to obtain nanofibers in various diameters with high surface area. Titanium dioxide (TiO2) is often used in biomaterial technologies due to their high biocompatibility, high processability and their photocatalytic activities in waste water treatment. In this study, TTIP (Titanium tetra isopropoxide) was used as a TiO2 precursor and PVP polymer was used as a carrier polymer for electrospinning. Avocado seed extract (ASE) which is a new and valuable source of phenolic compounds was used for the coordination and reduction of TTIP. TiO2-PVP-Avocado seed extract (T/P/A) composite nanofibers were produced at different voltages, distances and polymer concentrations. Crystalline TiO2 formation was not observed in as-spun nanofibers, thus selected nanofibers were heat treated at 500oC for 3 h. Smooth and integrated TiO2 nanofibers prepared by using 5 w% PVP, at 15 kV and 15 cm distance with or without ASE were imaged by Scanning Electron Microscopy (SEM). X-ray Diffraction (XRD) patterns of heat-treated TiO2 nanofibers prepared in the presence of ASE were crystallized mainly in anatase form. However, both anatase and rutile phases were obtained in the crystalline structure of TiO2 nanofibers when ASE was not used. Specific IR vibrations of TiO2 were shown by Fourier Transform Infrared Spectroscopy (FTIR). These green synthesized electrospun TiO2 nanofibers may have potential to be used in biomaterial and engineering applications
High-value–added products from microalgae production integrated with bioethanol process
No full textTwo-third of the earth's biomass is composed of microalgae. In recent years, there has been considerable discussion about the competition between conventional and advanced biofuels based on bioenergy potential. This review studies biomass-based bioethanol production, especially third-generation bioethanol production which is centered on the utilization of marine organisms like algae. In addition to energy utilization microalgae contain vast nutritional compounds for food, feed aquaculture, cosmetics, and pharmaceutical products. The overview of this review was to present the general microalgae stock for commercial bioethanol and its high-value components for different applications. © 2023 Elsevier Ltd. All rights reserved