SDG 9 · Sanayi, Yenilikçilik ve Altyapı · SDG · Erzincan Binali Yıldırım Üniversitesi

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ArticleAçık Erişim2024/r/ebyu/12405
Does economic globalization trigger de-industrialization in Western Balkan countries? Empirical evidence based on augmented mean group estimator
Cengiz, Orhan; Manga, Müge
Integration into the global economy can cause shifts in industries and decrease the industrial sector's share. Deindustrialization, which refers to declining industry share, is commonly observed in developed countries. However, many developing countries have also experienced deindustrialization without attaining a high economic level in the era of globalization. Since transitioning to a market economy and integrating with the European Union (EU), deindustrialization has become a significant issue for Western Balkan countries. Thus, our paper analyzes the impact of economic globalization on the deindustrialization process in five Western Balkan countries: Albania, Bosnia and Herzegovina, Montenegro, North Macedonia, and Serbia by using panel data spanning 2000–2019. Our study involved the creation of two models utilizing the augmented mean group (AMG) estimation method to ensure precise results. Our research shows that in model I, the economic globalization index, economic growth, capital investment, and the rule of law positively impact industry employment share. In model II, trade openness and economic growth positively affect manufacturing value-added; however, capital investment and the rule of law have a negative impact. Our findings indicate that economic globalization promotes industrialization in the Western Balkans instead of leading to deindustrialization. The panel causality results from Dumitrescu–Hurlin indicate that in model I, there is a one-way causal relationship going from economic globalization and capital investment to the share of industry employment. In model II, the causal relationship goes from economic growth and the rule of law to manufacturing value-added, from manufacturing value-added to trade openness and capital investment.
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ArticleAçık Erişim2024/r/ebyu/12377
Assessment of reinforced concrete building damages following the Kahramanmaraş earthquakes in Malatya, Turkey (February 6, 2023)
Ihsan Turan, Ahmet; Celik, Alper; Kumbasaroglu, Atila; Yalciner, Hakan
Earthquakes of magnitude Mw = 7.7 and Mw = 7.6 hit the city of Kahramanmaraş (Turkey) on 6 February 2023. These earthquakes caused serious damage in 11 provinces in Turkey resulting in over 50,000 deaths and huge economic losses with the collapse of thousands of buildings. Two consecutive devastating earthquakes have severely damaged the reinforced concrete building stock located in Malatya. There are many reasons reinforced concrete structures suffer damage under the influence of seismic loads. These reasons can be listed as material and section properties that do not comply with earthquake codes, workmanship defects, ground parameters that are not considered and design errors, as seen in field investigations after earthquakes in Turkey in the past. In this research, a field study was conducted on reinforced concrete buildings damaged after the earthquakes in Malatya province. The causes of structural damages in reinforced concrete buildings between 6–26 years of age were assessed in terms of design and material defects. The structural damages were mainly caused due to insufficient stirrups in structural members, short column, strong beam–weak column, failures of infill walls, soft story type collapse, poor concrete quality, and reinforcement corrosion. In addition to the field investigation, the spectrum relationships created using raw acceleration data obtained from DEMP (Disaster and Emergency Management Presidency) stations in Malatya province were compared with the design response spectra.
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ArticleAçık Erişim2024/r/ebyu/12375
A different approach for green concrete production: Determination of the effect of e-waste and waste rubber powder on durability properties of concrete
Bulut, H. Alperen
This study was carried out to present a different approach to green concrete production by utilizing electronic waste (e-waste) and waste rubber powders in order to provide a solution to both the cost and carbon footprint problems arising from the rapid consumption of aggregate resources and cement. For this purpose, 0%, 5% and 10% of ewaste was utilized instead of aggregate and 0%, 2.5% and 5% of waste rubber powder was utilized instead of cement. In addition, mixtures in which both wastes were combined in concrete were also prepared and comparisons were conducted. Capillary water absorption, acid and sulfate attack tests were carried out on the concretes with different wastes at the end of 28 and 90 days. The capillary water absorption of concrete produced with 5% waste rubber powder at the end of 28 days (P5E0/28) was 80% less than the control concrete (C/28) (these values were 0.46, 2.36 respectively). It was determined that the utilization of waste rubber powder had a decreasing effect on the compressive strength losses of the concretes after acid attack compared to the control concrete, while e-waste had an increasing effect. It was determined that the compressive strength losses of the concretes in which waste rubber powder and e-waste were combined against sulfate attack were positively differentiated from both control concrete and concretes produced with single waste type. In parallel with the weight and compressive strength losses obtained after acid and sulfate attack, the results of the visual analyses of the concretes were similar. The use of 5% waste rubber powder in the concrete produced the greatest results. In addition, the ideal ratio between concretes in which e-waste and waste rubber powder used together was determined as 5% waste rubber powder and 5% e-waste. The results verified that e-waste and waste rubber powder can be considered for the production of green concrete.
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ArticleYalnız künye2024/r/ebyu/12347
Deep learning-based forecasting modeling of micro gas turbine performance projection: An experimental approach
Kilic, Ugur; Villareal-Valderrama, Francisco; Ayar, Murat; Ekici, Selcuk; Amezquita-Brooks, Luis; Karakoc, T. Hikmet
Performance forecasting of aeroengines is crucial for achieving better operational efficiency, ensuring safety, reducing costs, and minimizing environmental impact in the aviation industry. It enables engineers and researchers to make informed decisions, leading to advancements in technology and the overall evolution of aviation. This study is focused on the effects of flight conditions on the performance of a turbojet, which in consequence affects the environmental aspect of operation. By investigating the relationships between aeroengine efficiency and performance indicators such as thrust, shaft speed, and exhaust gas temperature (EGT), and flight characteristics expressed in terms of environmental and operational conditions, the study seeks to elucidate these connections. The article's significance lies in its successful application of Long Short-Term Memory (LSTM) networks to predict thrust, shaft speed, and EGT variations in turbojet engines under varying flight conditions. Experimental data from a turbojet test bench is processed with deep learning, specifically LSTM recurrent neural networks that are developed based on Matrix Laboratory (MATLAB). The model inputs are free stream air speed, compressor inlet pressure, combustor inlet temperature, combustor inlet pressure, turbine inlet temperature, turbine inlet pressure, nozzle inlet pressure and fuel flow, and the outputs are thrust, shaft speed and EGT. Predicted thrust closely aligns with actual thrust values, though with minor discrepancies. Shaft speed predictions exhibit a similar trend, while EGT predictions showcase a comparable pattern with slight variations. Despite the prediction errors, a thorough evaluation of median values, box plots, and probability density functions confirms that the models effectively capture available information, though discrepancies may arise from measurement inaccuracies and initial engine conditions. These results show that it is possible to accurately predict turbojet performance using LSTM recurrent neural network. This research paves the way for enhanced aeroengine performance prediction, particularly in scenarios requiring off-board or high-performance applications.
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ArticleYalnız künye2024/r/ebyu/12340
DC–DC converter with multiple inputs and full isolated multi ports charging battery in photovoltaic energy systems
Can, Erol
The need for functional photovoltaic systems with multiple inputs used in energy storage devices is increasing day by day. In addition to having sufficient performance, these units are a good alternative to integrated converters with their low costs. In terms of these advantages, a multi-port DC–DC converter is recommended for solar energy systems in this study. In this multi-pot system, each port has a specific purpose. Two of them are renewable sources, one is the battery set and the other is the load port. Although this topology is developed for standalone systems, it can be easily adapted to other different applications. The system can provide energy from each input source independently or by combining them, and any renewable source can be charged to extend the life of the battery set, whether discharged or charged. While the system can provide energy in some periods of time without the need for input sources or by combining all elements in the system, a different renewable source can also be used to extend the life of the discharged or charged battery set. A few extra features make the system superior to other existing systems; First of all, the PV source and battery are directed to the same point. Sometimes, only the solar cell charges the battery, providing safe grounding for both, and secondly, the output is isolated from other connection points. These advantages are given by comparing them with existing systems. The advantage that is different from other topologies is that the proposed method can continue battery charging in 3 ways with the switches reserved for PVs. The first is discontinuous mode, the second is semi-continuous mode and the third is continuous mode. This mode of operation is preferred according to the amount of energy received from the sun. In this way, it offers a functional charging capability. After the proposed system design and numerical studies, it is also applied experimentally.
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ArticleYalnız künye2024/r/ebyu/12284
Thermal performance improvement of an air-cooled 18650 NMC battery module: A novel busbar design that acts as a turbulator
Kalkan, Orhan
Today, Lithium-ion batteries are preferred as popular energy storage tools in many fields such as electronic devices, especially electric vehicles. During the discharge of modules and packs formed by combining many battery cells, undesirable temperature increases are experienced due to excessive heat generation. Thus, thermal management of the battery packs is crucial. In this work, thermal and hydraulic performance analysis of the two air-cooled 18650 NMC battery modules, one with a novel designed twisted busbar and the other with a conventional busbar, are performed numerically. Temperature and pressure drop predictions are achieved at different values of air inlet velocity, discharge rate, depth of discharge, and twist diameter of busbar using CFD method. Besides, the Multi-Scale Multi-Domain battery model is validated experimentally. According to the numerical results, the novel designed twisted busbar provides 1.84 %, 2.93 %, and 3.81 % reduction in maximum battery module temperature for 5 m/s air inlet velocity under discharge rates of 2C, 3C and 4C, respectively. The average battery module temperature drops by 6.6 °C thanks to the use of a twisted busbar. Using a twisted busbar results in a maximum pressure drop increase of 119 Pa compared to the conventional busbar. As the twist diameter of the busbar increases, the battery temperature decreases significantly, and the pressure drop increases, especially at high air velocity conditions. In addition, when the twist diameter increases from 5 mm to 15 mm, the weight/volume ratio increases by approximately 0.9 %.
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ArticleYalnız künye2024/r/ebyu/12282
The experimental investigation of seepage control in different sand soils using photopolymerization
Akoğuz, Harun
Seepage control is critically essential for dams, slopes, and the stability of many engineering structures, developing over many years using different methods. This study presents a novel approach for seepage control using the photopolymerization technique to form an impermeable crust at the soil surface. Effects of exposure duration (5, 10, 15, and 30 min) and light intensities (140, 550, 710, and 1000 W/m2) on the seepage control effectiveness of four different sand soils were investigated by using the photopolymerization technique. The three-point bending, permeability and acid rain simulation tests were performed to illustrate the effect of photopolymerization on the seepage control of sand soils. Furthermore, the influence of photopolymerization on the microstructure of soils was examined with the aid of SEM analysis. The results indicated that the photopolymerization technique could improve the crust strength, acid rain durability, and permeability of sand soils. The crusts at the surface layer of soils were formed after the photopolymer was applied to the sand surface and then exposed to UV light. These crusts of different soils have bending strengths and thicknesses in the range of 34.57 and 68.07 MPa, 2.13 and 6.18 mm, respectively. The increase in exposure duration and light intensity, resulted in the gradual increment of soil crust thickness. On the other hand, the increase in light intensities have more effective on the crust thickness. The formed soil crust has been provided an impermeable surface that prevents the weight loose from the surface of the soil under acid rain conditions. The SEM analysis indicated that the photopolymerized gels were homogeneously distributed between the grains in all samples, although the grain distribution of soils were different. Since the photopolymerization method has a short treatment duration and is easier to apply on the sand surface, the occurrence of the crust at the soil surface by this technique may open a new and improvable path for seepage control. The obtained results showed that the photopolymerization method is promising for repairing, restoring, and strengthening the construction materials in different engineering areas, as well as seepage control.
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ArticleAçık Erişim2024/r/ebyu/12257
Investigation of The Use of Nano Powder On Roller Compressible Fibrous Concrete Roads
Sünbül, Şeyma; Tortum, Ahmet
Despite the fact that our country's road network is inferior to that of industrialized countries, the volume of motor traffic is increasing. Thus, optimal solutions are imperative during both project and construction phases of highway investments. Concrete superstructures offer an alternative to flexible superstructures in various regions globally, including airport runways, warehouses, urban roads, streets, highways and industrial buildings. The objective of this study was to enhance the compressive and flexural strength of concrete and provide resistance against abrasion. To achieve this, a roller compressible concrete (RCC) mixture design was developed by incorporating basalt fiber, nano TiO2, and nano Fe2O3 additives. The experimental results were subjected to statistical analysis via the technique of analysis of variance (ANOVA). The findings of the study indicated that the strength performance of the optimal RCC mixture design reinforced with nano powder and fibers was superior to that of conventional concrete. Upon examination on a material basis, it was determined that the compressive strength exhibited an increase when the water/binder ratio was utilised within the range of 0.38–0.4. As the utilisation of nano-Fe2O3 and basalt fiber materials increased, their compressive strength exhibited a corresponding enhancement. The incorporation of basalt fiber into the composite material resulted in an increase in flexural strength at all ratios where it was utilised. It can be concluded that basalt fiber has the greatest potential for enhancing flexural strength. The optimal water-to-binder ratio for flexural properties is between 0.34 and 0.38. While nano powders can have a positive impact, they cannot achieve the maximum level of strength. For improving abrasion resistance, it was established that reducing the water/cement ratio, using fly ash, basalt fiber, and nano Fe2O3 in the mixture decreased abrasion. However, the usage of nano TiO2 did not have a significant positive effect. The material with the least effect on compressive, flexural and abrasion resistance was identified as nano TiO2. When materials other than nano TiO2 are utilised in accordance with the established optimal mixture calculation, the durability of the resulting RCC road will reach the requisite standard.
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ArticleYalnız künye2024/r/ebyu/12225
Can digital government reduce the resource dependency? Evidence from method of moments quantile technique
Destek, Mehmet Akif; Hossain, Mohammad Razib; Manga, Müge; Destek, Gamze
The conventional thinking states that pervasive government corruption may turn resource plenty in resource-rich countries into a burden. These issues may surface, particularly when the public sector uses conventional procedures. Based on this, the research looks at how the public sector's digitalization might aid in resolving this issue. Specifically, economic growth, trade openness, economic complexity index, public sector size, and the impacts of digitalization are assessed in relation to their reliance on natural resources for 16 nations that are vulnerable to the “curse of the natural resource” Furthermore, the moderating influence of digitalization on the link between the growth of the public sector and the resource curse is investigated. In this case, the years 1995–2021 are investigated using the CS–ARDL methodology, and the robustness of the results is evaluated using the Moments Quantile Regression method. The CS-ARDL approach's findings indicate that trade openness, public sector size, and economic progress all correlate with increased resource reliance. However, as the economy becomes more complex and digitalized, resource dependency declines. Additionally, it is demonstrated that the interaction term parameter between digitalization and the growth of the public sector is negative, indicating that digitalization within the public sector has the potential to counteract the growing reliance of the sector on resources.
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ArticleAçık Erişim2024/r/ebyu/12057
Integrated Design Optimization Process for Building Projects
Aslay, Semi Emrah; Dede, Tayfun; Kaveh, Ali
In this study, a cost-design optimization is conducted for a reinforced concrete structure with irregular voids and inclined axes, which is a real-world application. Data transfers are performed on a 3D model to achieve the optimization. Data exchange is managed automatically by the created software program. As an application example, a hospital building with 10 beds is considered. Optimum design and minimum cost values are obtained for optimization processes using the Rao algorithms. The construction cost values are compared both among algorithms and with actual cost values, indicating a successful optimization process. The software program developed in this study accelerates the processes in optimization operations, thereby contributing to the realization of automatic data transfers.
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ArticleAçık Erişim2024/r/ebyu/11994
Sediment load forecasting from a biomimetic optimization perspective: Firefly and Artificial Bee Colony algorithms empowered neural network modeling in Çoruh River
Katipoğlu, Okan Mert; Kartal, Veysi; Pande, Chaitanya Baliram
The service life of downstream dams, river hydraulics, waterworks construction, and reservoir management is significantly affected by the amount of sediment load (SL). This study combined models such as the artificial neural network (ANN) algorithm with the Firefly algorithm (FA) and Artificial Bee Colony (ABC) optimization techniques for the estimation of monthly SL values in the Çoruh River in Northeastern Turkey. The estimation of SL values was achieved using inputs of previous SL and streamflow values provided to the models. Various statistical metrics were used to evaluate the accuracy of the established hybrid and stand-alone models. The hybrid model is a novel approach for estimating sediment load based on various input variables. The results of the analysis determined that the ABC-ANN hybrid approach outperformed others in SL estimation. In this study, two combinations, M1 and M2, with different input variables, were used to assess the model's accuracy, and the best-performing model for monthly SL estimation was identified. Two scenarios, Q(t) and Q(t − 1), were coupled with the ABC-ANN algorithm, resulting in a highly effective hybrid approach with the best accuracy results (R2 = 0.90, RMSE = 1406.730, MAE = 769.545, MAPE = 5.861, MBE = − 251.090, Bias Factor = − 4.457, and KGE = 0.737) compared to other models. Furthermore, the utilization of FA and ABC optimization techniques facilitated the optimization of the ANN model parameters. The significant results demonstrated that the optimization and hybrid techniques provided the most effective outcomes in forecasting SL for both combination scenarios. As a result, the prediction outputs achieved higher accuracy than those of a stand-alone ANN model. The findings of this study can provide essential resources to various managers and policymakers for the management of water resources.
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ArticleAçık Erişim2024/r/ebyu/11938
Portable Acceleration of CMS Computing Workflows with Coprocessors as a Service
Hayrapetyan, A.; Tumasyan, A.; Adam, W.; Andrejkovic, J.W.; Bergauer, T.; Chatterjee, S.; Damanakis, K.; Dragicevic, M.; Hussain, P.S.; Jeitler, M.
Computing demands for large scientific experiments, such as the CMS experiment at the CERN LHC, will increase dramatically in the next decades. To complement the future performance increases of software running on central processing units (CPUs), explorations of coprocessor usage in data processing hold great potential and interest. Coprocessors are a class of computer processors that supplement CPUs, often improving the execution of certain functions due to architectural design choices. We explore the approach of Services for Optimized Network Inference on Coprocessors (SONIC) and study the deployment of this as-a-service approach in large-scale data processing. In the studies, we take a data processing workflow of the CMS experiment and run the main workflow on CPUs, while offloading several machine learning (ML) inference tasks onto either remote or local coprocessors, specifically graphics processing units (GPUs). With experiments performed at Google Cloud, the Purdue Tier-2 computing center, and combinations of the two, we demonstrate the acceleration of these ML algorithms individually on coprocessors and the corresponding throughput improvement for the entire workflow. This approach can be easily generalized to different types of coprocessors and deployed on local CPUs without decreasing the throughput performance. We emphasize that the SONIC approach enables high coprocessor usage and enables the portability to run workflows on different types of coprocessors.
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ArticleAçık Erişim2024/r/ebyu/11821
Performance Comparison of Various Tunnel Lighting Scenarios on Driver Lane-Changing Behaviours in a Driving Simulator
Ozturk, Omer Faruk; Mazlum, Yusuf; Aydin, Metin Mutlu; Coruh, Emine; Bayata, Halim Ferit
Recent advances in tunnel infrastructure have emphasized safety, operational efficiency and low operating costs. Modern tunnels are equipped with systems to improve both safety and operational performance. This study investigates the effect of tunnel lighting and vehicle breakdown scenarios on driver lane changing behaviour (LCB) using a driving simulator modelled on the third longest twin-tube tunnel. Data were collected from 125 drivers considering various driver characteristics with different lighting conditions and the presence of a stopped vehicle in a lane. The results show that drivers tend to slow down and change lanes more safely in response to red and flashing lights. In contrast, blue sky lights, which are designed to reduce stress and compare with other dangerous scenarios, had no significant effect on LCB. In addition, demographic factors such as gender and previous simulator experience played a role in influencing LCB tendencies. Female drivers and those familiar with simulators showed more cautious behaviour. The findings showed valuable insights into how tunnel lighting systems can improve safety. Results highlighted the potential for dynamic lighting and targeted driver training programs to improve tunnel safety. All these findings may contribute to ongoing efforts to improve traffic management and reduce accidents in tunnel environments.
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ArticleAçık Erişim2024/r/ebyu/11786
Analysis of hybrid AC/DC transmission system: A Turkey case study
Karaca, Eda; Nuroğlu, Fatih Mehmet
The need to transmit energy in the most effective way arises in parallel with the demand for energy in developing countries. As the amount of transmitted power increases, transmission lines can become overloaded, causing a blackout. This study aims to increase the transmission capacity without experiencing right-of-way problems by converting Turkey's existing high voltage AC systems to hybrid AC/DC systems. With such a design, it is aimed at providing more efficient and continuous transmission by using the high-voltage DC system's low-loss feature at long distances. Using the 400 kV double circuit line structure, the existing electricity transmission system is modelled using real data in the DigSILENT PowerFactory. The electromagnetic fields that will occur due to the use of AC and DC circuits on the same tower in such a transformation situation are analysed with FEMM 4.2, based on the finite element method. The compliance of the electromagnetic fields that will occur with the use of hybrid 400 kV AC and 500 kV DC was determined in the study. In addition, according to the simulation results, it is predicted that in the case of hybrid AC/DC transmission, the current transmission capacity would increase and the losses would decrease.
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ArticleAçık Erişim2024/r/ebyu/11784
Performance of steel protective structure for historical masonry aqueducts against rockfall: Numerical and field studies
Cosgun, Suleyman Istemihan; Nasery, Mohammad Manzoor
This study investigates the design and impact performance of novel steel protection system intended to safeguard historical masonry aqueducts from damage caused by hazardous rocks. The historical aqueduct under consideration is located on the Sumela Monastery campus. To achieve this, we developed a three-dimensional (3D) photogrammetric model of the study area and identified all risky blocks along with their real positions. Subsequently, we conducted 3200 probabilistic rockfall analyses in eight critical trajectories with four different rock sizes to calculate the velocity, kinetic energy, and run-out distance of fallen blocks. In the second part of the study, finite element models of the steel protective structure were created using Abaqus software. A nonlinear dynamic impact analysis method was applied to analyze nine rockfall scenarios with two different geometries and four different sizes. Based on the rockfall and impact analyses, sections of the protection structure were designed using plastic design criteria. The steel protection structure for aqueducts demonstrated high effectiveness against rockfall, with a risk index (Ir) ranging from 0.93 to 1.00 (except for the upper end of the column–beam connection impacts). Even in these scenarios, the structure provided protection by reducing rock energy and altering its trajectory. In the third part, a steel structure was constructed in the field, and a rock cleaning process was carried out. During rock cleaning, punctures occurred while breaking sharp rocks. To mitigate this risk, a parametric study was conducted using a steel angle stopper. The proposed simple steel angle stopper effectively reduced rockfall damage to historical structures by blocking rock passages and rapidly reducing kinetic energy. Ultimately, during the removal of 5000 m³ of hazardous rocks, no damage was inflicted on the historical structure. The protection system showed a near 100 % success rate in safeguarding the aqueduct. This temporary structure can be employed to protect historical structures from rockfall hazards.
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ArticleAçık Erişim2023/r/ebyu/20104
Travel option-based environmental comparison between passenger aircraft and high-speed rail
Çam, Ömer; Kilic, Ugur
The short-haul flights have higher emission values than medium or long-haul flights when emissions per distance are considered. In this study, the potential to reduce greenhouse gas emissions by replacing short-haul flights which carried out by a narrow-body commercial aircraft from/to Konya City in Turkey with regional jets or high-speed trains (HSRs) has been investigated. The flight trajectory is selected from Konya Airport to İstanbul Sabiha Gökçen Airport, and that trajectory is a frequently performed domestic flight between Konya and İstanbul. The IMPACT platform is used for the calculation of fuel burn and gas emissions. According to the results, traveling with regional jets or high-speed trains from/to Konya City which is the most 15th polluted city in Europe, provides advantages in terms of environmental impact. Traveling with HSR which is the best traveling option in this study, provides approximately 3.3 times more green travel than the currently used narrow-body passenger aircraft between Konya and İstanbul. In addition, this mode of transportation can become more environmentally friendly by using renewable energy sources to produce its electricity needs. It is expected that this study will serve as a guide for airline and high-speed rail operators and regulators to determine the most environmentally efficient travel options based on fuel burn and emission parameters.
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ArticleAçık Erişim2023/r/ebyu/20099
E-ticaret yönetiminde kullanılan dağıtım araçlarının bütünleşik crıtıc ve edas yöntemi ile seçilmesi
Oğuz, Alparslan
E-ticaret hacmi son yıllarda ciddi artış göstermiştir. Müşterilerin e-ticaret platformları üzerinden aldığı ürünlerin ulaştırılması işletmeler için kritik süreçlerden biridir. Bu sürecin önemli bileşenlerinden biri de kent içi dağıtımda kullanılan araçlardır. Çalışmanın amacı, çok kriterli karar verme yöntemleri ile işletmeler için kent içi dağıtım aracı seçiminin analiz edilmesidir. Bu bağlamda kent içi dağıtımda yaygın olarak kullanılan dokuz scooter model çalışmaya dahil edilmiştir. Alternatif modellerin değerlendirilmesinde sekiz objektif kriter kullanılmıştır. Kullanılan kriterlere ait ağırlıklar CRITIC yöntemi ile belirlenmiştir. Alternatifler arasında sıralama ise EDAS yöntemi ile yapılmıştır. Analizler sonucu en yüksek öneme sahip kriterin servis ücreti olduğu belirlenmiştir. Çalışmaya dokuz model katılmış ve alternatifler arasında A4 modeli ilk sırayı almıştır.
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ArticleAçık Erişim2023/r/ebyu/19981
Experimental Study on the Pull-Out Capacity of Blind Rivet Nuts (BRNs) Mounted on Cold-Formed Square Hollow Section Members with Different Wall Thickness
Cosgun, Suleyman Istemihan
In this study, pull-out tests of blind rivet nuts (BRNs) mounted on cold-formed square hollow section (SHS) webs with 100×100 mm nominal cross-section dimensions and different wall thicknesses (2.0 to 5.0 mm) were performed, and the effect of different wall thicknesses and BRN thread sizes on the test results was experimentally investigated. M10 and M12 stainless steel BRNs were mounted on SHSs using a standard riveter tool, and the test elements were prepared for the experiment. Load–displacement curves and the final damage modes were obtained for each test specimen. The results show that the pull-out capacity depends on both the SHS wall thickness and rivet nut thread size. Although the pull-out capacity increased in both thread sizes with the increase in wall thickness parameters, the effect of thread size is negligible in the case of 2.5, 3.0, and 4.0 wall thickness. In addition, when a connection is created using a BRN, the design should consider the stripped thread strength in addition to the pull-out capacity.
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ArticleAçık Erişim2023/r/ebyu/19917
Mikrobiyal Aracılı Kalsit Çökelmesi (MICP) Tekniğinde Çimentolama Solüsyonu Enjeksiyonuna Sodyum Aljinat Yoğunluğunun Etkisinin İncelenmesi
Akoğuz, Harun
Günümüzde zeminlerin iyileştirilmesi için birçok farklı metot kullanılmaktadır. Bu metotların birçoğu çevreye zararlı bileşenler içerdiğinden alternatif zemin iyileştirme yöntemlerine ihtiyaç duyulmaktadır. Bu kapsamda zemin iyileştirme yöntemlerine çevreci bir yaklaşım olarak ortaya çıkan Mikrobiyal Aracılı Kalsit Çökelmesi (MICP) tekniği ile zeminlerin mühendislik özellikleri iyileştirilebilmektedir. Ancak MICP tekniği ile zeminlerin iyileştirilmesinde karşılaşılan problemlerden biri uygulama süresidir. Uygulama süresi genelde oldukça fazla olan MICP tekniği için farklı uygulamalara ihtiyaç duyulduğu anlaşılmaktadır. Bu amaçla çalışmamızda çimentolama solüsyonuna (kalsiyum klorür) ilave edildiğinde uygulama süresini azaltabilecek bir biyopolimer türü olan sodyum aljinatın enjeksiyon özellikleri incelenmiştir. Farklı yoğunluklarda hazırlanan sodyum aljinat solüsyonu zemine enjeksiyon yöntemiyle verilerek zemin içerisindeki dağılımı uygulama süresince takip edilmiş ve sonuçlar permeabilite deneyi ve Taramalı Elektron Mikroskobu (SEM) analizi ile değerlendirilmiştir. Sonuç olarak çimentolama solüsyonuna ilaveten sodyum aljinat kullanımının tüm yoğunluklarda (0.1 g/l, 0.3 g/l, 0.6 g/l) permeabilite üzerinde olumlu sonuçları olmuştur. Daha düşük yoğunluklarda ise (0.1 g/l) uygulama süresi biraz daha artmış ancak daha iyi geçirimlilik sonuçlarıyla beraber daha homojen bir dağılım elde edilebilmiştir. SEM analizleri sonucunda oluşan jel yapının taneler arasında bağ oluşturduğu gözlemlenmiştir. MICP tekniği ile zeminlerin iyileştirmesinde düşük yoğunluklarda (en fazla 0.1 g/l) sodyum aljinat kullanımının uygulama süresine olumlu etkisinin olabileceği değerlendirilmiştir.
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ArticleAçık Erişim2023/r/ebyu/19108
Orient Ekspres’ten Turistik Doğu Ekspresi’ne: Türkiye’de demiryollarının turistik önemi üzerine bir inceleme
Orhan, Fatih; Hocaoğlu, Hüseyin
Dünya turizminin gelişiminde demiryolu ulaşımı öncü rol üstlenmiştir. Ancak ülkemizde karayolu ulaşımına ağırlık verilerek demiryolunun geri planda bırakılması, gelişmiş bir demiryolu ağına ulaşılmasını engellemiştir. Bu durum gerek genel olarak yolcu taşımacılığında ve gerekse turizm ulaştırmasında demiryolunun geri kalmasına vesile olmuştur. Ancak son yıllarda Doğu Ekspresi (DE)’nin turistik açıdan rağbet görmeye başlaması ve Ankara-Kars güzergâhında özellikle turistlere hizmet edecek Turistik Doğu Ekspresi (TDE) seferlerinin hizmete konulması, demiryollarının turistik önemine dikkatleri çekmiştir. Bu bağlamda çalışmada, TDE örneği üzerinden geçmişten günümüze demiryollarının ülkemiz turizmine olan etkisi incelenmiş ve demiryolu turizminin ülkemizde canlandırılması için önerilerde bulunulmuştur. Betimsel araştırma deseninin tercih edildiği araştırmanın veri kaynağını ise ilgili kurumlardan elde edilen istatistiki veriler ile saha gözlemleri oluşturmaktadır. TDE, hem yolcularına sunduğu nostaljik yolculuk deneyimi hem de güzergâhı boyunca sahip olduğu manzara avantajı nedeniyle turistlerin yoğun ilgisini çekmiştir. Bu durum, varış destinasyonu olan Kars ilinde turistik hareketlilik oluşturduğu gibi, güzergâh boyunca uzun süreli molaların verildiği yerlerde de bir canlanmaya vesile olmuştur. Bununla birlikte seferlerinin tüm yıla yayılması ve diğer bazı alternatif turizm türleri ile entegre bir yapıya dönüştürülmesi, sürdürülebilir turizm gelişimine daha fazla hizmet edecektir. Ayrıca TCDD bünyesindeki diğer bazı ana hat güzergâhlarında da benzer uygulamalar gerçekleştirilebilir.
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