İnşaat Mühendisliği Bölümü Koleksiyonu

Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/205

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Application of Smoothed Particle Hydrodynamics to Structural Cable Analysis
(MDPI, ST ALBAN-ANLAGE 66, CH-4052 BASEL, SWITZERLAND, 2020) Dincer, A. Ersin; Demir, Abdullah; AGÜ, Mühendislik Fakültesi, İnşaat Mühendisliği Bölümü
In this study, a numerical model is proposed for the analysis of a simply supported structural cable. Smoothed particle hydrodynamics (SPH)-a mesh-free, Lagrangian method with advantages for analysis of highly deformable bodies-is utilized to model a cable. In the proposed numerical model, it is assumed that a cable has only longitudinal stiffness in tension. Accordingly, SPH equations derived for solid mechanics are adapted for a structural cable, for the first time. Besides, a proper damping parameter is introduced to capture the behavior of the cable more realistically. In order to validate the proposed numerical model, different experimental and numerical studies available in the literature are used. In addition, novel experiments are carried out. In the experiments, different harmonic motions are applied to a uniformly loaded cable. Results show that the SPH method is an appropriate method to simulate the structural cable.
Ardıl Baraj Yıkılmasının Mansapta Bulunan Elastik Yapı Üzerindeki Etkisinin Yapı-Sıvı Etkileşim Yöntemi ile İncelenmesi
(Iğdır Üniversitesi, 2020) Dincer, Ali Ersin; Demir, Abdullah; 0000-0002-4662-894X; 0000-0002-6392-648X; AGÜ, Mühendislik Fakültesi, İnşaat Mühendisliği Bölümü; Dincer, Ali Ersin; Demir, Abdullah
Bu çalışmada yazarlar tarafından geliştirilen bir yapı-sıvı etkileşim yöntemi idealize edilmişardıl baraj yıkılması problemi için test edilmiştir. Bu doğrultuda geliştirilen yöntemde, sıvı kısımyumuşatılmış tanecik hidrodinamiği (smoothed particle hydrodynamics - SPH) ile, katı kısım ise sonluelemanlar (finite element – FE) yöntemi ile modellenmiş ve katı ile sıvı arasındaki akupaj, kontakmekanik kullanılarak gerçekleştirilmiştir. Aynı geometrideki ardıl barajlar aralarında mesafebırakmaksızın yerleştirilmiştir. En yüksek konumdaki barajın doluluk oranındaki değişim dikkatealımıştır. Yıkılan barajların mansaptaki elastik bir yapıya etkisi hem yapının deformasyonu yönündenhem de akışkandaki basınç dağılımları yönünden test edilmiştir. Ayrıca serbest akışkan yüzeyi profillerive su hızı profilleri de çalışmada sunulmuştur.
Arsenic removal by the micellar-enhanced ultrafiltration using response surface methodology
(IWA PUBLISHING, ALLIANCE HOUSE, 12 CAXTON ST, LONDON SW1H0QS, ENGLAND, 2020) Gokcek, Oznur Begum; Uzal, Nigmet; 0000-0002-0912-3459; 0000-0003-1730-2905; AGÜ, Mühendislik Fakültesi, İnşaat Mühendisliği Bölümü
The present research investigates the removal of arsenic (As) from aqueous solutions using micellar-enhanced ultrafiltration (MEUF) by utilizing two different surfactants: benzethonium chloride and dodecyl pyridinium chloride (BCl and DPCl). The impact of the operating variables and maximum removal efficiency were found under different conditions for BCl and DPCl surfactants. The maximum As rejection efficiency for MEUF with BCl and DPCl surfactants is 92.8% and 84.1%, respectively. In addition to this, a statistics-based experimental design with response surface methodology was used for the purpose of examining the impact of operating conditions, including initial pH, initial As concentration (ppb), and surfactant concentration (BCl, mM) in As-removal from aqueous solutions. In the analysis of the experimental data, a second-order polynomial model that was validated by statistical analysis for the BCl surfactant was used. On the basis of the response model created, the removal of As ions was acquired at optimum operating parameters, including the initial As concentration of 150 ppb, surfactant concentration of 5 mM and pH 10 for the BCl surfactant with 92.8% As-removal efficiency.
Batık Minarelerde Su Seviyesinin Yapıya Olan Etkisinin Sayısal Olarak İncelenmesi
(Iğdır Üniversitesi, 2021) Demir, Abdullah; Dinçer, Ali Ersin; 0000-0002-6392-648X; 0000-0002-4662-894X; AGÜ, Mühendislik Fakültesi, İnşaat Mühendisliği Bölümü; Demir, Abdullah; Dincer, Ali Ersin
Baraj göllerinin, sular altında bıraktığı yerleşim yerlerinin, su üstünde kalan son mirasları minarelerdir. Türkiye’de iki adet batık minare bulunmaktadır ve su üstünden görülebilmeleri ile cazibe merkezleri haline gelmişlerdir. Uzun yıllar sular altında kalması bu yapıların malzeme kalitesinin düşmesine sebep olmuştur/olacaktır. Bunun yanında; olası bir deprem esnasında var olan zemin hareketine ek olarak suyun çalkalanma etkisinin de eklenmesi bu minarelerin davranışlarının öngörülmesini daha da zorlaştırmaktadır. Yüksek Deprem riski barındıran bölgelerde yer alan her bu yapıların deprem esnasında su ile yapacağı etkileşimin sonuçlarının irdelenmesi gerekmektedir.Bu kapsamda su altında kalan minarelerin davranışlarını incelemek için idealleştirilmiş 2 boyutlu model oluşturulmuş ve yakın fay hareketleri uygulanmıştır. İdealleştirilmiş modelin analizi için tam akupajlı bir yapı-sıvı etkileşim (FSI) modeli kullanılmıştır. Bu modelde yapı kısmın modellenmesi için sonlu elemanlar yöntemi (FEM), sıvı kısmın modellenmesi için ise yumuşatılmış parçacık hidrodinamiği (SPH) kullanılmıştır. Bu iki farklı yöntem ile modellenen alanların etkileşimi için ise kontak mekanik kullanılmıştır. Kullanılan FSI yöntemi birçok problemin çözümü ile doğruluğu kanıtlanan geçerli bir yöntemdir. Farklı su seviyeleri ile oluşturulan idealleştirilmiş modeller, geliştirilen FSI yöntemi ile analiz edilmiş ve sonuçlar karşılaştırmalı olarak sunulmuştur. Elde edilen sonuçlar batık minarelerde su kütlesi etkisinin yakın fay altında ne kadar yüksek olduğunu ortaya koymaktadır. Su seviyesindeki değişim ile bu etki doğal olarak değişim göstermektedir. Çalışma kapsamında farklı su seviyeleri incelenerek batık minareler üzerindeki su kütlesi etkisi ayrıntılı olarak incelenmiştir.
Carbon Dioxide Absorption Using Different Solvents (MEA, NaOH, KOH and Mg(OH)2) in Bubble Column Reactor
(Bitlis Eren Üniversitesi, 2023) Gül, Ayşe; Tezcan Un, Umran; 0000-0002-2305-6408; AGÜ, Mühendislik Fakültesi, İnşaat Mühendisliği Bölümü; Gül, Ayşe Ayşe; Tezcan Un, Umran
Carbon dioxide is considered to be one of the greenhouse gases potentially responsible for climate change. The aim of this research is to reduce emissions by capturing carbon dioxide in a solution using an absorption method. The absorption capacity, absorption rate, carbon dioxide removal efficiency, and overall mass transfer coefficient of MEA (Monoethanolamin) and alkaline solvents (NaOH, KOH, Mg (OH)2) were investigated using a bubble column gas absorption reactor with counter current flow. The effects of operational parameters such as solvent concentration (0.01, 0.05, and 0.25M) and solvent type were studied. The research showed that KOH, NaOH, and MEA were more efficient in capturing CO2 than Mg (OH)2 was. For all solvent types, the total mass transfer coefficient, absorption rate, and CO2 removal efficiency were increased with the increase in the concentration of solvent. The solvent concentration is increased from 0.01 M to 0.25 M to obtain the highest KGa values for MEA, NaOH, and KOH, 3.75 1/min for MEA, 3.70 1/min for NaOH, and 3.93 1/min for KOH.The MEA, NaOH, and KOH absorption rates were maximum at 0.25 M solvent concentrations as 0.19x103 mol/Ls. The maximum CO2 removal efficiencies for MEA, NaOH, and KOH at 0.25 M solvent concentration are greater than 60%. Absorption capacity of NaOH and KOH is 0.313 mol CO2/mol NaOH and 0.316 (mol CO2/mol KOH). The highest absorption capacity, 0.576 mol CO2/mol MEA, was obtained at a solvent concentration of 0.01M MEA.
Carbon dioxide absorption using monoethanolamine, piperazine and n-metil-2-pirolidon solvents under counter current regime in packed column reactor
(ELSEVIER SCI LTD, 2024) Gul, Ayse; Barış, Mesut; Un, Umran Tezcan; 0000-0002-2305-6408; AGÜ, Mühendislik Fakültesi, İnşaat Mühendisliği Bölümü; Gul, Ayse
In this research the carbon dioxide absorption using Monoethanolamine (MEA), Piperazine (PZ) and N-Metil-2-pirolidon (NMP) solvents and their different blends (MEA/NMP, PZ/NMP, MEA/PZ) in packed column reactor filled with Raschig rings was investigated and compared for efficient carbon dioxide absorption. The process was followed in a countercurrent regime under a liquid flow rate of 200 mL/min, gas flow rate of 2.5 L/min, and CO2 concentration of 50,000 ppm. Carbon dioxide removal efficiency (%), absorption capacity (mol CO2/mol solvent), overall mass transfer coefficient (1/min) and absorption rate (mol/l.s) were monitored. The highest obtained values for carbon dioxide removal efficiency, absorption capacity and overall mass transfer coefficient were 57.5%, 0.148 mol CO2/mol solvent and 2.178 min-1 respectivelly when 0.03 M MEA/0.07 M PZ in a hybrid system was used. It was concluded that PZ blends with MEA were successful absorbent as the organic physical solvent whereas NMP didn't show improving effect in blends with MEA on the absorption efficiency.
A Comparative Study on the VS30 and N-30 Based Seismic Site Classification in Kahramanmaras, Turkey
(HINDAWI LTD, ADAM HOUSE, 3RD FLR, 1 FITZROY SQ, LONDON, W1T 5HF, ENGLAND, 2020) Naji, Dalia Munaff; Akin, Muge K.; Cabalar, Ali Firat; 0000-0001-8873-5287; 0000-0002-9279-2257; 0000-0002-0390-5652; AGÜ, Mühendislik Fakültesi, İnşaat Mühendisliği Bölümü
Assessment of seismic site classification (SSC) using either the average shear wave velocity (V-S30) or the average SPT-N values (N-30) for upper 30 m in soils is the simplest method to carry out various studies including site response and soil-structure interactions. Either the V-S30- or the N-30-based SSC maps designed according to the National Earthquake Hazards Reduction Program (NEHRP) classification system are effectively used to predict possible locations for future seismic events. The main goal of this study is to generate maps using the Geographic Information System (GIS) for the SSC in Kahramanmaras city, influenced by both East Anatolian Fault and Dead Sea Fault Zones, using both V-S30 and N-30 values. The study also presents a series of GIS maps produced using the shear wave velocity (V-S) and SPT-N values at the depths of 5 m, 10 m, 15 m, 20 m, and 25 m. Furthermore, the study estimates the bed rock level and generates the SSC maps for the average V-S values through overburden soils by using the NEHRP system. The V-S30 maps categorize the study area mainly under class C and limited number of areas under classes B and D, whereas the N-30 maps classify the study area mainly under class D. Both maps indicate that the soil classes in the study area are different to a high extent. Eventually, the GIS maps complied for the purpose of urban development may be utilized effectively by engineers in the field.
Comparison of Mechanical and Physical Properties of Screed with and without Expanded Polystyrene (EPS) Particles
(YILDIZ TEKNİK ÜNİVERSİTESİ, 2022) Kılıç, Fikret Merih; Yorulmaz, Hediye; Özuzun, Sümeyye; Durak, Uğur; İlkentapar, Serhan; Karahan, Okan; Atiş, Cengiz Duran; 0000-0002-1015-4308; AGÜ, Mühendislik Fakültesi, İnşaat Mühendisliği Bölümü; Yorulmaz, Hediye
In this study, in order to observe the mechanical and physical properties of ordinary screed, sandy-lightweight screed and lightweight screed samples, expanded polystyrene (EPS) was used as fine aggregate and lightweight screed systems were produced by replacing sand at 100%, 50% and 0%. Samples of cement dosages of 250, 300, 350 kg/m3 were produced for lightweight screeds, sandy-lightweight screeds and ordinary screeds. Unit weight, water absorption capacity, flexural strength, compressive strength, fire resistance, abrasion and thermal conductivity tests were performed on the produced screed systems. As a result of the research, it was determined that as EPS ratio increases in screed system; unit weights decreased, water absorption rates increased. Besides, the flexural and compressive strengths, fire and abrasion resistance are also decreased. However, it was observed that the thermal conductivity coefficient reduced with the increment of EPS particles in the screed. In normal, sandy-lightweight and lightweight screeds, it was determined that as the cement dosage increased; the unit weights, flexural and compressive strengths, fire and abrasion resistance increased, water absorption capacity and the thermal conductivity coefficient decreased.
Compatibility and Biomineralization Oriented Optimization of Nutrient Content in Nitrate-Reducing-Biogranules-Based Microbial Self-Healing Concrete
(MDPIST ALBAN-ANLAGE 66, CH-4052 BASEL, SWITZERLAND, 2021) Kardogan, Beyza; Sekercioglu, Kadir; 0000-0003-4128-0195; AGÜ, Mühendislik Fakültesi, İnşaat Mühendisliği Bölümü; Ersan, Yusuf Cagatay
Microbially induced calcium carbonate precipitation (MICP) can be mentioned among the popular approaches to develop a self-healing concrete. The production of dissolved inorganic carbon through microbial activity is the main precursor for MICP in concrete and it is limited by the bioavailability of the nutrients. When nutrients are added to the mortar as admixtures, their bioavailability becomes more significant for crack repair because nutrients disperse in the mortar and considerable fraction stays far from a single crack. Therefore, the determination of bioavailability of nutrients and its variation with the initial nutrient content and crack age is essential to optimize a recipe for bacteria-based self-healing concrete. This study presents the optimum nutrient content defined for nitrate-reduction-based self-healing bioconcrete. In the tests, calcium nitrate (CN) and calcium formate (CF) were combined with a CF:CN w/w ratio of 2.50. Mortar properties and bioavailability of nutrients were analysed at different nutrient doses. Moreover, the bioavailability of nutrients at different crack ages changing between 3 and 56 days was monitored. Finally, resuscitation, microbial activity and the MICP performance of nitrate reducing biogranules were tested at defined nutrient bioavailabilties. The optimum nutrient content was determined as 7.00% (CF 5.00% and CN 2.00%). The leaching rates of formate ions were twice the leaching rate of the nitrate ions at similar initial concentrations, which led to a bioavailable HCOO-/NO3-N ratio of 23 g/g in cracked mortar. Under optimum nutrient conditions, the CaCO3 precipitation yield of nitrate reducing biogranules was recorded as 1.5 g CaCO3/g HCOO- which corresponded to 68% C precipitation efficiency.
Determining datum temperature and apparent activation energy: an approach for mineral admixtures incorporated cementitious systems
(Tulpar Academic Publishing, 2024) Atasever, Muhammet; Tokyay, Mustafa; 0000-0001-7375-8152; AGÜ, Mühendislik Fakültesi, İnşaat Mühendisliği Bölümü; Atasever, Muhammet
The maturity method is used to predict the strength of concrete by monitoring its temperature history. Accuracy of maturity method relies on the dependable determination of the datum temperature and the apparent activation energy. The current study introduces a new approach, complementing those in ASTM C1074-11, for determining the datum temperature and apparent activation energy. The experimental study involved using two different mineral additives to portland cement at 6%, 20%, and 35% replacement amounts. The mortars were then cured at temperatures of 5, 20, and 40 °C, and their strengths were determined. Subsequently, the datum temperatures and apparent activation energies for these mixtures were calculated using both the proposed approach and the alternatives from ASTM C1074-11. Strength estimations were conducted in conjunction with commonly used maturity functions. The results indicate that the proposed approach determines the datum temperature and apparent activation energy reliably for mineral admixture-incorporated mortars. Furthermore, the predicted strengths, derived from the datum temperature and apparent activation energy calculated through the proposed approach, show a closer alignment with the experimental results when applying the Nurse-Saul and HansenPedersen equations, as opposed to the Rastrup and Weaver-Sadgrove models
Developing empirical formulae for scour depth in front of inclined bridge piers
(Croatian Association of Civil Engineers, 2023) Fedakar, Halil İbrahim; Dincer, Ali Ersin; Bozkuş, Zafer; 0000-0002-7561-5363; 0000-0002-4662-894X; AGÜ, Mühendislik Fakültesi, İnşaat Mühendisliği Bölümü; Fedakar, Halil İbrahim; Dincer, Ali Ersin
Because of the complex flow mechanism around inclined bridge piers, previous studies have proposed different empirical correlations to predict the scouring depth in front of piers, which include regression analysis developed from laboratory measurements. However, because these correlations were developed for particular datasets, a general equation is still required to accurately predict the scour depth in front of inclined bridge piers. The aim of this study is to develop a general equation to predict the local scour depth in front of inclined bridge pier systems using multilayer perceptron (MLP) and radial-basis neural-network (RBNN) techniques. The experimental datasets used in this study were obtained from previous research. The equation for the scour depth of the front pier was developed using five variables. The results of the artificial neural-network (ANN) analyses revealed that the RBNN and MLP models provided more accurate predictions than the previous empirical correlations for the output variables. Accordingly, analytical equations derived from the RBNN and MLP models were proposed to accurately predict the scouring depth in front of inclined bridge piers. Moreover, from the sensitivity analyses results, we determined that the scour depths in front of the front and back piers were primarily influenced by the inclination angle and flow intensity, respectively.
Düzce kent merkezi zeminlerinin sıvılaşma potansiyelinin değerlendirilmesi
(TMMOB - Jeoloji Muhendisleri Odasi, 2019) Akin, Muge K.; AGÜ, Mühendislik Fakültesi, İnşaat Mühendisliği Bölümü; Akin, Muge K.
Soil liquefaction is one of the ground deformations occurred during an earthquake which may cause serious damages such as settlement and tilting of structures due to loss of bearing capacity of foundations. Düzce and its surrounding settle on a plain which consists of silty and sandy layers with shallow groundwater level. Besides, the North Anatolian Fault Zone is a major seismic source which is capable of producing large magnitude earthquakes. All these data point out that the ground deformations like liquefaction and lateral spreading may occur during a probable large earthquake around Düzce and its close vicinity. In this study, the geotechnical data of 40 boreholes drilled to determine the local ground conditions and the groundwater level in Düzce were considered. Based on the field studies, it was aimed to evaluate the liquefaction potential considering the fact that the groundwater level is shallow as well as the subsurface soil is composed of loose alluvium. Liquefaction Potential Index (LPI) and Liquefaction Severity Index (LSI) methods were taken into account and the liquefaction potential of Düzce province was determined and mapped with respect to various earthquake scenarios in GIS environment. These maps are compared on the basis of different scenarios. Accordingly, it is concluded that the liquefaction potential is high-very high in the south and south-eastern sections of the study area where the construction of new residential buildings progressively continues. © 2019 Jeoloji Muhendisligi Dergisi. All rights reserved.
Effect of characteristics of natural zeolites on their geopolymerization
(ELSEVIERRADARWEG 29, 1043 NX AMSTERDAM, NETHERLANDS, 2021) Ozen, Sevgi; Uzal, Burak; AGÜ, Mühendislik Fakültesi, İnşaat Mühendisliği Bölümü; Uzal, Burak
The properties of clinoptilolite-based geopolymers are investigated with a focus on the parameters affecting the reactivity of clinoptilolite in a geopolymer binder. A complete characterization of raw materials was carried out as well as a determination of the mineralogical composition, microstructure and mechanical properties of geopolymers. The results of the investigation show that of the investigated materials, geopolymer made with clinoptilolite-bearing tuff from Bayburt has the highest compressive strength. The chemical and mineralogical characteristics of a raw material are important parameters that potentially control the geopolymeric reaction, whereas physical properties (particle size and BET specific surface area) are mainly influential at early stages of geopolymerization. Geopolymeric gel was found to be the main reaction product through characterization by XRD and SEM analysis. The geopolymer produced with the raw material from Bayburt had a narrow range of Si/Al ratios and possessed a geopolymer binder structure with an advanced nature. Lastly, in addition to clinoptilolite, feldspar has an additional effect on the geopolymeric reaction and enhances the process, especially at later ages.
Effect of urbanization on surface runoff and performance of green roofs and permeable pavement for mitigating urban floods
(SPRINGER NATURE Link, 2024) Öztürk, Şevki; Yılmaz, Kutay; Dincer, Ali Ersin; Kalpakcı, Volkan; 0000-0002-4662-894X; AGÜ, Mühendislik Fakültesi, İnşaat Mühendisliği Bölümü; Dincer, Ali Ersin
Floods are increasingly becoming a significant concern due to climate change, global warming, and excessive urbanization. The Intergovernmental Panel on Climate Change (IPCC) has projected that global warming will continue to contribute to more frequent and severe floods and hydrological extremes. In response to these challenges, nature-based solutions (NBSs) have gained recognition as effective approaches to mitigate the adverse impacts of floods by focusing on ecosystem conservation, restoration, and sustainable utilization of natural resources. This study examines a flood that occurred in the Erkilet District of Kayseri, Türkiye on September 22, 2022, as a result of intense rainfall. It involves a thorough on-site investigation to assess the hydraulic, hydrologic, and geotechnical attributes of the study area. The findings from the field study indicate that the primary cause of the flood is attributed to excessive urbanization. To further analyze the impact of urbanization, a hydraulic model is developed considering both the physical and topographical conditions of the study area for both the year 2006 and 2022. The simulation results reveal that the extent of inundation area and water depth has increased significantly due to the excessive urbanization that occurred within a 16-year period. Additionally, the effectiveness of green roofs and permeable pavements as NBSs to mitigate urban flooding is explored. The implementation of green roofs and permeable pavements shows promising results, reducing the adverse effects of urban floods by 3% to 8%, depending on their specific locations and configurations. However, the results suggest that NBSs alone cannot fully prevent floods so they should complement gray infrastructure. The novelty of the study lies in its ability to demonstrate the impact of urbanization and the effectiveness of nature-based solutions in mitigating flood extent based.
The Effects of Different Types of Fly Ash on the Compressive Strength Properties of Briquettes
(HINDAWI LTD, ADAM HOUSE, 3RD FLR, 1 FITZROY SQ, LONDON, W1T 5HF, ENGLAND, 2011) Sola, Ozlem Celik; Yayla, Murat; Sayin, Baris; Atis, Cengiz Duran; AGÜ, Mühendislik Fakültesi, İnşaat Mühendisliği Bölümü;
The aim of this study is to evaluate the effect of the different types of fly ash on the compressive strength properties of sintered briquettes. Thermal gravimetric (TG) analysis was carried out. The chemical composition and physical properties of the materials used were determined. Particle size distribution and microstructure elemental analyses of the materials used were carried out by a particle size analyzer (Mastersizer) and a scanning electron microscope (SEM-EDS). Following the characterization of the materials, briquettes were prepared by sintering at different temperatures. Compressive strength test results of the briquette samples indicated that briquettes with a compressive strength value of 47.45 N/mm(2) can be produced. The results obtained exceed the Turkish standard (TS EN 771-1) requirements (9.8-23.54 N/mm(2)). SEM-EDS results showed that briquette samples made with Tuncbilek (T) fly ash had a higher percentage of the glassy phase than the other briquette samples. Due to this microstructure, it results in higher compressive strength value.
Effects of dry particle coating with nano- and microparticles on early compressive strength of portland cement pastes
(Tulpar Academic Publisher, 2021) Yorulmaz, Hediye; Uzal, Burak; Özuzun, Sümeyye; İlkentapar, Serhan; Durak, Uğur; Karahan, Okan; Atiş, Cengiz Duran; 0000-0002-1015-4308; 0000-0001-6892-6692; 0000-0002-3810-7263; 0000-0002-9932-2899; 0000-0001-7970-1982; 0000-0003-3459-329X; 0000-0003-2731-3886; AGÜ, Mühendislik Fakültesi, İnşaat Mühendisliği Bölümü; Yorulmaz, Hediye; Uzal, Burak
It is known that nano-and microparticles have been very popular in recent years since their advantages. However, due to the very small size of such materials, they have very high tendency to agglomeration particularly for nanoparticles. Therefore, it is critical that they are properly distributed in the system to which they are added. This paper investigated the effects of dry particle coating with nano-and microparticles to solve the agglomeration problem. For a clear evaluation, paste samples were preferred to detemine the compressive strength. Nano-SiO2 and nano-CaCO3, micro-CaCO3 and micro-SiO2, also known as silica fume, were selected as particulate additives. It was studied by the addition of various percentages (0.3, 0.7, 1, 2, 3 and 5%) of nano-and microparticles in cementitious systems, replacing cement by weight with and without dry particle coating. Dry particle coating was made by using a high-speed paddle mixer. Portland cement and additive particles were mixed at 1500 rpm for 30 seconds in high-speed powder mixer designed for this purpose. The 3-day compressive strength of the cement-based samples to which particles were added at the specified rates was determined and the effect of the dry particle coating on the early strength was investigated. According to the results, it was observed that the production of paste with the dry particle coating technique gave higher compressive strength compared to the production of paste directly in early period. Especially with dry particle coating, compressive strength increased more than 100% in paste samples containing 0.3% nano-SiO2 compared to direct addition without coating.
Efficiency of L-DOPA+TiO2 modified RO membrane on salinity gradient energy generation by pressure retarded osmosis
(Pamukkale Üniversitesi, 2024) Ateş, Nuray; Saki, Seda; Gokcek, Murat; Uzal, Niğmet; 0000-0001-8923-2323; 0000-0002-0912-3459; AGÜ, Fen Bilimleri Enstitüsü, Malzeme Bilimi ve Makine Mühendisliği Ana Bilim Dalı; SAKİ, Seda; Uzal, Niğmet
Harvesting energy from the salinity gradient of seawater and river water using pressure retarded osmosis (PRO) has been a major research topic of recent years. However, there is a need for efficient PRO membranes that can generate high power density and are pressure resistant, as the performance of current membranes on the market is poor. In this study, specific energy potential of PRO process using LDOPA+TiO2 modified BW30-LE membrane was evaluated on synthetic and real water samples. Polyamide BW30-LE RO membrane was modified by L-DOPA, L-DOPA+0.5 wt% TiO2 and L-DOPA+1 wt% TiO2. The effect of hydraulic pressure and temperature on generation of power density were evaluated for 5, 10, and 15 bar pressures, as well as 10 °C, 20 °C, and 30 °C degrees. The incorporation of TiO2 nanoparticles with L-DOPA increased the water flux by increasing the surface hydrophilicity and roughness of the membrane surface. The maximum specific power was observed as 1.6 W/m2 for L-DOPA+1 wt% TiO2 modified BW30-LE membrane at 15 bar pressure. Besides, Mediterranean and Aegean, Black Sea water samples were used as draw solution and Seyhan, Ceyhan, Buyuk Menderes, Gediz, Yesilirmak, and Kizilirmak Rivers were used as feed solution. The highest osmotic power density was obtained by using L-DOPA+1 wt% TiO2 modified BW30-LE membrane with Ceyhan River as feed and Mediterranean Sea water as draw solution, which have the highest differences in salinity. In the mixture of Mediterranean and Ceyhan River, the highest power density was obtained at 10 bar pressure at 30 ± 5°C with 0.70 W/m2 .
Emergency response, and community impact after February 6, 2023 Kahramanmaraş Pazarcık and Elbistan Earthquakes: reconnaissance findings and observations on affected region in Türkiye
(SPRINGER, 2024) Senol Balaban, Meltem; Dogulu, Canay; Akdede, Nil; Akoglu, Haldun; Karakayali, Onur; Yilmaz, Sarper; Yilmaz, Serkan; Ajobiewe, Tolulope; Guzel, Selin; Ikizer, Gozde; Akin, Muge; Unal, Yesim; Karanci, Ayse Nuray; 0000-0001-8873-5287; AGÜ, Mühendislik Fakültesi, İnşaat Mühendisliği Bölümü; Akın, Müge
Türkiye has a long history of devastating earthquakes, and on February 6, 2023, the region experienced two major earthquakes with magnitudes of 7.7 and 7.6, striking Pazarcık and Elbistan, Kahramanmaraş, respectively, on the East Anatolian Fault Zone. These earthquakes resulted in signifcant loss of life and property, impacting multiple cities across 11 cities, and leaving a lasting impact on the country. The 2023 Kahramanmaraş Earthquakes rank among the deadliest and most damaging earthquakes in Türkiye, alongside the historical signifcance of the 1939 Erzincan Earthquake and the 1999 Marmara Earthquake. Despite reforms following the 1999 Marmara Earthquake in disaster policy and preparedness, the scale of damage from the February 6 earthquakes has been shocking, necessitating further insights and lessons for future earthquake management. This paper presents the outcomes of immediate response eforts organized after the 2023 Kahramanmaraş earthquakes to elucidate emergency response activities and their impacts on communities, considering the substantial size and severity of the damages. The study focuses on evaluating the emergency response provided within the frst 24 h, 3 days, and 2 weeks after the earthquakes, aiming to promptly identify the nature and efectiveness of these responses, as well as the conditions that hindered their efcacy. By shedding light on the specifc experiences and challenges faced during these crucial timeframes, the research aims to ofer valuable insights and lessons learned. These fndings contribute to improved preparedness strategies and more efcient emergency response measures needed in responding to future disaster scenarios. Ultimately, this study provides a useful resource for all stakeholders involved in emergency response and disaster management, ofering valuable guidance to enhance resilience and preparedness in the face of seismic hazards.
Etriyesiz Dış Kiriş-Kolon Birleşim Bölgesi için Kesme Dayanımı Tahmini
(TÜBİTAK ULAKBİM Ulusal Akademik Ağ ve Bilgi Merkezi Cahit Arf Bilgi Merkezi, 2020) Eren YAĞMUR; AGÜ, Mühendislik Fakültesi, İnşaat Mühendisliği Bölümü
Çerçeve türü yapıların sismik yük altında sünek davranış sergilemesi kiriş-kolon birleşim bölgelerinin depremden kaynaklı olarak açığa çıkan reaksiyon kuvvetlerini sağlıklı bir şekilde aktarmasına bağlıdır. Ancak yüksek kesmeye maruz kalan birleşim bölgelerinde etriye sıklaştırması yapılırken çeşitli sorunlarla karşılaşılmakta ve bu sebeple de etriyeler gerektiği gibi yerleştirilememektedir. Sonuç olarak pek çok yapıda kiriş-kolon birleşim bölgesinde yetersiz etriye miktarı sebebi ile hasarlar meydana gelmektedir. Mevcut çalışmada, etriyesiz dış kirişkolon birleşim bölgelerinin kesme dayanımlarının belirlenmesi amacıyla yapılmış olan deney verileri derlenmiş ve bu verilere bağlı olarak birleşim bölgesinin kesme dayanımına etki eden temel parametreler belirlenmiştir. Bu parametreler: efektif birleşim bölgesi genişliği, beton silindir basınç dayanımı, eksenel kuvvet oranı ve kiriş efektif alanının kolon efektif alanına oranıdır. Söz konusu parametrelerden yola çıkılarak etriyesiz dış kiriş-kolon birleşim bölgelerinin kesme dayanımını hesaplamak amacıyla bir denklem önerilmiştir. Önerilen denklem literatürde yer alan ve aynı amaçla üretilmiş denklemlerin sonuçları ile karşılaştırılmıştır. Önerilen denklemin diğer denklem sonuçlarına kıyasla deney sonuçları ile daha uyumlu sonuçlar verdiği görülmüştür.
Experimental Investigation on the Bonding Strength of Knotted CFRP Bars in Bulk Plastics
(MDPI, 2023) Ciftci, Cihan; 0000-0001-9199-6437; AGÜ, Mühendislik Fakültesi, İnşaat Mühendisliği Bölümü; Ciftci, Cihan
Improving the interfacial bonding strength of CFRP materials is crucial for enabling the development of novel composite beam structures with higher specific bending strength demanded by the composite industry. In this research study, for reinforced bulk plastic composites, the aim is to enhance the interfacial bonding strength of CFRP bar elements in bulk plastics by on the formation of knots. In this context, firstly, the knotted CFRP bars with varying cross-sectional areas were manufactured under laboratory conditions for the experimental investigation on the effect of knots on bonding strength. Commercially available smooth-surfaced CFRP bars were also purchased to be used as the reference. Then, all these CFRP bars were subjected to pull-out tests by using in bulk plastics. According to the test results, it was observed that the interfacial bonding strength of CFRP bars in bulk plastic materials could be increased up to 233% because of the knots.

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