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Öğe The effects of Fe2O3 based DOC and SCR catalyst on the exhaust emissions of diesel engines(ELSEVIER SCI LTD, 2020) Reşitoğlu, İbrahim Aslan; Altınışık, Kemal; Keskin, Ali; Ocakoğlu, KasımThe effects of Fe2O3 based DOCs (Diesel Oxidation Catalyst) and SCR (Selective Catalytic Reduction) catalysts on the exhaust emissions of diesel engine were investigated in this experimental study. The investigated catalysts, Al2O3 - TiO2/CeO2/Fe2O3 (ATCF) and Al2O3- Nb2O5/CeO2/Fe2O3 (ANCF), were produced with impregnation method and aged for 6 h at 600 degrees C. FE-SEM (Field Emission Scanning Electron Microscopy), XRD (X-Ray Diffraction), XRF (X-Ray Fluorescence) and BET (Brunauer-Emmett-Teller) Surface Area analyzes were carried out to determine the specifications of catalysts. The catalytic performances of the DOCs were tested for the oxidation of CO, HC, PM, NO while SCR catalysts were tested for SCR of NOx using NH3. An individual exhaust system was built up and mounted to the engine for tests of catalysts. An electronic control system and a software were developed to control the SCR system. After the completion of experimental setup, catalysts placed inside the exhaust system were subjected to the engine tests to determine their effects on the exhaust emissions. Tests were carried out under actual working conditions with a single cylinder direct injection diesel engine. In conclusion, the catalysts made significant decrease in pollutant emissions while brake specific fuel consumption (BSFC) increased slightly. ANCF released better conversion efficiency in all pollutant emissions compared to the ATCF. Maximum decreases in CO, HC and NOx emissions, which are resulted from ANCF catalyst, were obtained at a rate of 83.51%, 80.83% and 80.29% respectively.Öğe The mechanical properties of composite materials recycled from waste metallic chips under different pressures(SPRINGER, 2019) Aslan, Abdullah; Salur, Emin; Güneş, Aydın; Şahin, Ömer Sinan; Karadağ, Hakan Burak; Akdemir, AhmetThe purpose of this study is to produce composite materials by utilizing the waste metallic chips. In this context, the metal matrix composite materials (MMCs) were produced at different production pressures and the effects of the different pressures on mechanical properties of MMCs were investigated. In the present investigation, spheroidal graphite cast iron (GGG-40) was used as reinforcement material in bronze (CuSn10) matrix system. The MMCs were produced by hot press with 20 wt% GGG-40 reinforcement ratio. The total time required for the production of one specimen was selected as 25 min and temperature was settled at 400 degrees C. In order to determine mechanical properties and consolidation mechanism of MMCs, Brinell and micro-Vickers hardness, porosity, compression and X-ray diffraction tests were conducted. In addition, microstructure views were examined to determine the consolidation quality of metallic chips. According to experimental results, it was observed that waste metallic chips can be successfully recycled into MMC final parts with approximately 40% porosity and almost 100% strength and 150% hardness with respect to bulk CuSn10 materials. Most of the presented studies in the literature present information about properties of MMCs fabricated by conventional production methods. However, no available data are found about the recycling of bronze-based MMCs which make this study more original. It is also shown in this study that waste metallic chips can be utilized by proposed recycling methodology, which is environmentally friendly in comparison with conventional recycling methods producing harmful gases for earth atmosphere.Öğe The effects of solid particle erosion of zm coating material on Gf/Ep and Cf/Ep composites by using PVD method(GAZI UNIV, 2019) Bagci, MehmetProtective coatings produced by using Physical Vapour Deposition (PVD) method can increase the life time of the components. Therefore; in this study, approximate to 0.25 mu m thickness ZrN coatings are applied on Glass Fiber Reinforced Epoxy (GF/EP) and Carbon Fiber Reinforced Epoxy (CF/EP) composites by magnetron sputtering to gain an improved understanding of the erosion resistance. The impingement angles used in the tests were 30 degrees, 60 degrees and 90 degrees, while the impact velocity was 53 m/s. Al2O3 abrasive particles with an average diameter of 200 mu m was used. All test specimens regardless of their various properties exhibit maximum erosion rates at 30 degrees impingement angle and thus exhibiting similar behavior as that observed for ductile materials. Optic microscopic views were performed on the surfaces in order to characterize the erosion mechanism. The erodent particles of the both coating layer and composite matrix were found of main role in governing the wear progression. The measured erosion rates were sensitively correlated with the material removal process in order to explain the changes within the coated interfaces.Öğe Numerical analysis of the influence of particular parts of the high efficient electric vehicle on the aerodynamic forces(LUBLIN UNIV TECHNOLOGY, POLAND, 2019) Czyz, Zbigniew.; Karpinski, Pawel.; Koçak, Salih.The work presents a three-dimensional modeling of air flow around the research object. The purpose of this work was to perform numerical calculations to identify the magnitude of the aerodynamic drag force generated on individual elements of a high energy efficiency vehicle body. This vehicle, specially designed for the Shell Eco-marathon competition, needs to show the lowest possible fuel consumption while maintaining the prescribed speed. Minimizing the drag force at an early designing stage plays an important role here. The calculations were performed using the ANSYS Fluent calculation solver. The result of the conducted research is a description of the velocity and pressure distributions around the tested vehicle as well as an identification of the drag force on the external surfaces of the components and a description of the relationship between them. The work also discusses the dependence of the drag force as a function of speed in the range from 0 to 12 m/s. The influence of the ground on the drag force in the case when the object was immobilized in relation to the walls at the flowing medium, as in a wind tunnel, was investigated. On the basis of the calculations performed, no impact of the ground on the generated drag force magnitude was found.Öğe ChipsLow-velocity impact behavior of porous metal matrix composites produced by recycling of bronze and iron chips(SPRINGER, 2019) Şahin, Ömer Sinan; Güneş, Aydın; Aslan, Abdullah; Salur, Emin; Karadağ, Hakan Burak; Akdemir, AhmetIn this study, the low-velocity impact behavior of porous metal matrix composites (MMCs) has been investigated. The MMCs consisting of spheroidal cast iron chips (GGG-40) and bronze chips (CuSn10) were produced by hot isostatic pressing. The MMCs were produced with different CuSn10 contents as 90-80-70-60%. The hot isostatic pressing was performed under three different pressures and temperatures. The produced MMCs were exposed to low-velocity impact loading under 2m/s by using a drop weight test stand. The test results were compared with the bulk CuSn10 and bulk GGG-40, separately. The test results revealed that hot-isostatic-pressed MMCs can successfully represent bulk material properties when subjected to low-velocity impact loading even these MMCs have porosity 2-8%.Öğe Internal flow analysis of a porous burner via CFD(EMERALD GROUP PUBLISHING LTD, 2019) Abdulkarim, Ali Hussein; Ateş, Ali; Altınışık, Kemal; Canlı, EyübPurpose This study aims to introduce a metal porous burner design. Literature is surveyed in a comprehensive manner to relate the current design with ongoing research. A demonstrative computational fluid dynamics (CFD) analysis is presented with projected flow conditions by means of a common commercial CFD code and turbulence model to show the flow-related features of the proposed burner. The porous metal burner has a novel design, and it is not commercially available. Design/methodology/approach Based on the field experience about porous burners, a metal, cylindrical, two-staged, homogenous porous burner was designed. Literature was surveyed to lay out research aspects for the porous burners and porous media. Three dimensional solid computer model of the burner was created. The flow domain was extracted from the solid model to use in CFD analysis. A commercial computational fluid dynamics code was utilized to analyze the flow domain. Projected flow conditions for the burner were applied to the CFD code. Results were evaluated in terms of homogenous flow distribution at the outer surface and flow mixing. Quantitative results are gathered and are presented in the present report by means of contour maps. Findings There aren't any flow sourced anomalies in the flow domain which would cause an inefficient combustion for the application. An accumulation of gas is evident around the top flange of the burner leading to higher static pressure. Generally, very low pressure drop throughout the proposed burner geometry is found which is regarded as an advantage for burners. About 0.63 Pa static pressure increase is realized on the flange surface due to the accumulation of the gas. The passage between inner and outer volumes has a high impact on the total pressure and leads to about 0.5 Pa pressure drop. About 0.03 J/kg turbulent kinetic energy can be viewed as the highest amount. Together with the increase in total enthalpy, total amount of energy drawn from the flow is 0.05 J/kg. More than half of it spent through turbulence and remaining is dissipated as heat. Outflow from burner surface can be regarded homogenous though the top part has slightly higher outflow. This can be changed by gradually increasing pore sizes toward inlet direction. Originality/value Conducted analysis is for a novel burner design. There are opportunities both for scientific and commercial fields.Öğe In-situ growth of NiWO4 saw-blade-like nanostructures and their application in photo-electrochemical (PEC) immunosensor system designed for the detection of neuron-specific enolase(ELSEVIER ADVANCED TECHNOLOGY, 2019) Soomro, Razium Ali; Kalwar, Nazar Hussain; Avci, Ahmet; Pehlivan, Erol; Hallam, Keith Richard; Willander, MagnusThis study describes the construction of highly-sensitive photo-electrochemical (PEC) immunosensor for the detection of neuron-specific enolase (NSE). The biosensing platform is comprised of photo-active NiWO4 nanostructures, in-situ-grown over a conductive substrate (indium tin oxide) using a low-temperature template-based co-precipitation approach. The discussed approach enables the formation of discrete, yet morphologically-analogous, nanostructures with complete coverage (pinhole-free) of the electrode surface. The in-situ-grown nanostructure possess dense population with sharp saw-blade like morphological features that can support substantial immobilisation of anti-NSE agent. The constructed platform demonstrated excellent photo-catalytic activity towards uric acid (UA) which served as the base for the Electrochemical -mechanism (EC) based PEC inhibition sensing. The detection of NSE, relied on its obstruction in analytical signal observed for the photo-oxidation of UA after binding to the electrode surface via protein-antibody interaction. The constructed PEC immunosensor exhibits signal sensitivity up to 0.12 ng mL(-1) of NSE with excellent signal reproducibility and electrode replicability. Moreover, the constructed platform was successfully used for NSE determination in human serum samples.Öğe Experimental study and analysis of machinability characteristics of metal matrix composites during drilling(ELSEVIER SCI LTD, 2019) Salur, Emin.; Aslan, Abdullah.; Kuntoglu, Mustafa.; Gunes, Aydin.; Sahin, Omer Sinan.In this study, the metal matrix composite materials were produced by hot press with various production parameters. The drilling experiments were performed on computer numerical control vertical machining centre without cutting fluid. Analysis of variance (ANOVA) was carried out in order to determine the effects of the production parameters on thrust force and surface roughness of metal matrix composites drilled with different feed rate. The effect of production parameters such as temperature, pressure and reinforcement ratio were investigated, and their effects were presented. The optimal level for each production parameters was determined by 'Maximize the S/N ratio approach with a Taguchi design'. The test results revealed that the reinforcement ratio was the main factor affecting the surface roughness of the metal matrix composites for both feed rate. However, same singularity was not matter on thrust force due to close contribution rates of production parameters and high error rates of analysis. In literature, an increase on the thrust force and the surface roughness values was reported as the feed rate increased during machining. Nevertheless, in our MMCs system, the thrust force and the surface roughness values were in tendency of declination / as the feed rate increased which makes this study more novel research.Öğe Enzyme-free colorimetric sensing of glucose using L-cysteine functionalized silver nanoparticles(SPRINGER INTERNATIONAL PUBLISHING AG, 2019) Adnan, Sumaira; Kalwar, Nazar Hussain; Abbas, Malik Waseem; Soomro, Razium Ali; Saand, Mumtaz Ali; Awan, Fazli Rabbi; Avcı, Ahmet; Pehlivan, Erol; Bajwa, SadiaThe study demonstrates an efficient, simple and on-site viable approach for sensitive determination of blood glucose using colorimetric sensing approach. The devised colorimetric sensor works based on cysteine functionalized silver nanoparticles. The as-synthesized Ag NPs were elaborately characterized using advanced analytical techniques such as ultra-violet visible spectroscopy, Fourier transform infrared spectroscopy, transmission electron microscopy, atomic force microscopy and X-ray diffraction. The detection of glucose was carried under ambient air conditions where change in the optical characteristics of Ag NPs and subsequent interaction between glucose and functional moiety (i.e. surface bind cysteine) of Ag NPs was considered as the signal response. This interaction led to direct detection of glucose in the concentration range between 0.01 to 0.17 mu M with limit of detection up to 1 x 10(-4) mu M. It is worthwhile mentioning that success of the assay lies in application of the developed colorimetric sensor in real blood glucose measurements, which also proved its capability for field based analysis. In addition its simple design, low cost, and more reliability signifies the usefulness of colorimetric sensor and it can be extended monitor other biologically important molecules.Öğe Warm Hydromechanical Deep Drawing of AA 5754-0 and Optimization of Process Parameters(ASME, 2018) Acar, Doğan; Türköz, Mevlüt; Gedikli, Hasan; Halkacı, Hüseyin Selçuk; Cora, Ömer NecatiWarm hydromechanical deep drawing (WHDD) has increasingly been implemented by automotive industry due to its various benefits including mass reduction opportunities in auto body-in-white components and improved formability for lightweight alloys. In the first part of the current study, WHDD of AA 5754-0 was studied. In order to obtain the highest formability, an optimization study was performed for AA 5754-0 WHDD process parameters (tool temperature, hydraulic pressure (HP), and blank holder force (BHF) loading profiles) through finite element analysis (FEA) + experimentation approach. Results showed that the optimal temperature for punch is 25 degrees C and 300 degrees C for die and blank holder. In addition, HP was found to be more effective on formability when compared to BHF. Both fast increasing HP and blank holder loading profiles contributes to higher formability.Öğe Bronz ve dökme demir talaşlarının geri dönüştürülmesiyle prizmatik şekilli makine elemanı üretimi ve mekanik karakterizasyonu(2018) Aslan, Abdullah; Salur, Emin; Güneş, Aydın; Şahin, Ömer Sinan; Karadağ, Hakan Burak; Akdemir, AhmetBu çalışmada küresel grafitli dökme demir (GGG-40) ve Bronz (CuSn10) talaşlarının izostatik sıcakpresleme yöntemiyle geri dönüştürülmesi ile üretilen metal matrisli kompozit malzemelerin (MMK) üretimive mekanik davranışları incelenmiştir. MMK malzemeler 4 farklı karışım oranında 3 farklı sıcaklıkta ve 3farklı basınçta üretilerek üretim parametrelerinin gözeneklilik, sertlik ve eğilme mukavemeti üzerine etkisiincelenmiştir. Prizmatik geometrili olarak üretilen numunelerin öncelikle gözeneklilik ve yoğunluk değerleritespit edilmiştir. Daha sonra Brinell ve Mikro Vickers ve 3 noktadan eğilme deneyleri ile MMKmalzemelerin mukavemeti belirlenmiştir. Optik mikroskopi tekniği ile mikro yapı görüntüleri incelenerektalaşların birleşme mekanizması incelenmiştir. Ayrıca XRD analizi aracılığıyla metalik talaşlar arasında arafaz oluşumu olup olmadığı sorgulanmıştır. Gözeneklilik deneyleri neticesinde %20 mertebelerindegözeneklilik elde edilmiştir. Aşırı plastik deformasyon gösteren CuSn10 sebebiyle mukavemeti artanCuSn10 talaşları sertlik değerini Bulk CuSn10 ile kıyaslanabilir seviyelere getirmiştir. Eğilme deneyineticesinde MMK malzemelerin eğilme mukavemetleri bulk CuSn10’dan düşük çıkmıştır. Sonuç olarakmetal talaşların başarılı bir biçimde metal matris kompozit haline getirilebileceği gösterilmiştir.Öğe İşaret parmağı hareketini taklit eden eksik tahrikli dış iskelet geliştirilmesi(2018) Canlıdinç, Melih; Güleşen, Mustafa; Botsalı, Fatih Mehmet- İnsanın günlük faaliyetlerde en çok kullandığı uzvu el ve parmaklarıdır. Bu çalışmada, çeşitli nedenlere bağlıolarak el parmaklarının hareketinde kayıp oluşan hastaların rehabilitasyonu için eksik tahrikli bir parmakeksoskeletonu (dış iskeleti) tasarlanÖğe Optimization of Solid Particle Erosion by ZrN Coating Applied Fiber Reinforced Composites by Taguchi Method(2018) Bağcı, MehmetIn this study, ZrN coatings are applied on glass and carbon fiber reinforced epoxy composite materials by magnetron sputteringmethod to gain an improved understanding of the solid particle erosion (SPE) wear resistance. The tests were carried out byselecting two different impact velocities (34, 53 m/s), four different impingement angles (30, 45, 60, 90) and two differentabrasive (SiO2) particle sizes (approximate 250, 500 m). The thickness of ZrN coating material was 0.15 m. Protectivecoatings produced by using Physical Vapor Deposition (PVD) method can increase the life time of the components. All testspecimens regardless of their various parameter properties exhibit maximum erosion rates at 45 impingement angle and thusexhibiting similar behavior as that observed for semi ductile materials. Optic microscopic views were performed on thesurfaces in order to characterize the erosion mechanism. The erodent particles of the both coating layer and composite matrixwere found of main role in governing the wear progression. The measured erosion rates were sensitively correlated with thematerial removal process in order to explain the changes within the coated interfaces. Moreover, an erosion test facility at roomtemperature and Taguchi’s orthogonal arrays were used for experimentation. The expression derived from the results ofTaguchi experimental design is proposed as a predictive equation for estimation of erosion rate of these composites. It isdemonstrated that the predicted results from this equation are consistent with the experimental observations. Finally, anoptimal parameter combination was determined, which led to minimization of erosion rate (ER).Öğe 3B tarama yöntemiyle sac metal parçaların kalınlık dağılımlarının belirlenmesi(2017) Dilmeç, Murat; Öztürk, Fahrettin; Halkacı, Hüseyin SelçukSac metal parçaların kalınlık dağılımlarının belirlenmesinde en pratik çözümlerden birisi üç boyutlu (3B) tarama yöntemidir. Sac parçaların belirli bir kesitinden kesilerek, profil projeksiyon, SEM gibi hassas cihazlarla sadece o kesitinden ölçüm yapılması yerine, bu yöntemde, parça kesilmeden, tüm parça boyunca kalınlık dağılımları belirlenebilmektedir. Özellikle anizotropik davranış gösteren sac metal malzemeler için bu durum daha da önemlidir. Ancak, 3B tarama yöntemi ile sac parçaların taranmasında, iç ve dış yüzeyler arasında geçiş yaparken, ortak referans noktaların yakalanacağı bir açının elde edilmesi zordur. Parçaların iç ve dış yüzeyleri ayrı ayrı tarandığı zaman da, yüzeylerin eşleştirilmesinde problem yaşanmaktadır. Bu çalışmada, bahsedilen problemin çözümü için numunelerin flanş bölgelerine, farklı açılardan rahatça görülebilecek dikdörtgenler prizması şeklindeki referans parçaları yapıştırılmıştır. Bu sayede iç ve dış yüzeyler arası geçiş sağlanmıştır. 3B tarama yönteminin sac metal parçaların kalınlık dağılımlarının belirlenmesinde güvenle kullanılabileceğini test etmek için, şekillendirilmiş sac metal parçaların kalınlık dağılımları, 3B tarama, profil projeksiyon ve SEM ile ölçülmüş olup sonuçlar birbirleriyle karşılaştırılmıştır. Sonuç olarak, farklı yöntemlerle elde edilen kalınlık dağılımlarının birbirleriyle oldukça uyumlu olduğu görülmüştür. Dolayısıyla 3B yöntemi ile sac parçaların kalınlık dağılımlarının hassas olarak belirlenebileceği tespit edilmiştir. Böylece tersine mühendislik yoluyla 3B verileri elde edilen ince cidarlı derin parçalar 3B yazıcılarla hassas olarak üretilebilecektir. Ayrıca, sac metal parçaların geometrilerinin ölçülmesiyle kalite kontrol yapılarak Endüstri 4.0'ın alt yapısına kolaylık sağlamış olacaktırÖğe Designing of open cell aluminum foam heat exchanger and modelling of its thermal performance by using ann method(GAZI UNIV, 2016) Sertkaya, Ahmet Ali; Ateş, Ali; Altınışık, KemalThis study deals with the design and thermal performance modeling of aluminum foam open cell heat exchangers by making use of experimental data where the aluminum featuring different numbers of pores per inch (PPI) was used and the modeling was based on the Artificial Neural Networks (ANN) method. The open celled aluminum foams with 10, 20 and 30 PPI features were shaped into heat exchangers. The heat exchangers were placed into a rectangular groove then hot water was circulated within the heat exchanger tubings and cold air generated from a fan was blown over the tubings at varying rates. For every heat exchanger, the variations of Reynolds number with Nusselt number, pressure drop with air speed, and friction with Reynolds number were presented on graphs. By making use of the experimental data, ANN modeling was carried out for materials with 10, 15, 20, 25 and 30 PPI porous densities. The ANN input parameters for the developed system were T-hin, T-cin, T-hinw, u and PPI, whereas the output parameters were chosen to be T-hout, T-cout, T-houtw and Delta P. When the results from the Artificial Neural Networks were analyzed and compared with the experimental results, it was found that a close correlation exists between the two. With the result of this study, it becomes clear that the Artificial Neural Networks numerical modeling can be safely applied to aluminum foam heat exchangers.Öğe Detection of delaminations of laminar composites by infrared thermography(2016) Şahin, Ömer Sinan; Selek, MuratThe laminar composite materials may lost their bending stiffness and strength by formation of the delamination during production and service. However, these delaminations can be barely visible by the naked eye and thus the damage detection of composites materials is inspected generally in laboratory. In this study, the in situ detection of the delamination in laminar composite materials was investigated by using infrared thermography approach. First the composite materials were subjected to low velocity impacts to create arbitrary delamination. Then, these composites materials were exposed to cyclic bending loading and observed by using a thermal camera. The temperature variations caused by the friction within delaminated field have been investigated. It is shown that the delamination damages under cyclic loads cause to a serious internal friction and the delamination can be detected by infrared thermographyÖğe Effect of impactor mass on dynamic response and retention properties of composite plates under successive impacts(2016) Şahin, Ömer Sinan; Güneş, Aydın; Karadağ, Hakan BurakThis study mainly focuses on the effect of mass of impactor upon dynamic response of laminated composites. For this purpose two different impactors with different masses were used. The impact velocities were selected so that impactors with different masses had the same kinetic energy. The experiments were performed on simply supported woven E-glass reinforced epoxy laminates which are made of 8 layers stacked symmetrically. The variation of impact force, impactor velocity and laminate displacement versus interaction time were obtained. The impulse and energy absorption characteristics and damage zones were also investigated. After low velocity impact, the test specimens were subjected to three-point bending testing in order to get retention mechanical properties.Öğe Al 2024-T4 alaşımının nakajima testi ile elde edilen şekillendirme sınır eğrisinin minimum majör değerinin ötelenme nedenlerinin incelenmesi(2014) Dilmeç, Murat; Halkacı, Hüseyin Selçuk; Öztürk, FahrettinTipik bir şekillendirme sınır eğrisi (ŞSE)nde, minimum majör birim şekil değiştirme değeri, minör birim şekil değiştirme değerinin sıfır olduğu y ekseni üzerinde yer almaktadır. Birçok şekillendirme proseslerinde hasar bu bölgede meydana gelmektedir. Literatürde birçok çalışmada, ŞSElerde en düşük majör seviyesi hemen hemen y ekseni üzerinde elde edilmiştir. Bu çalışmada ise Al 2024-T4 alaşımı için bu değer, y ekseninden yaklaşık olarak 0,040 değerinde sağa doğru ötelenmiş olarak elde edilmiştir. Bu değer sac metal şekillendirme sonuçlarının değerlendirilmesinde önemli olabilmektedir. Bu çalışmada Al 2024-T4 sac metalin metalin minimum majör birim şekil değiştirme değerinin literatürden farklı olarak sağa ötelenmiş olarak elde edilmesinin nedenleri araştırılmıştır. Süzdürme çubuğu ve ısıl işlemin en fazla etki eden faktörler olduğu tespit edilmiştir. Ötelenmenin, süzdürme çubuğu kullanılarak yapılan testlerde oluşan ön BŞDlerden ve T4 ısıl işlemi sonucunda meydana gelen kalıntı gerilmelerden kaynaklandığı gözlenmiştir.Öğe Investigating the Effect of Sequent Gas Phase Lpg Injection System on Vehicle Performance and Exhaust Emissions(2012) Aydın, Fatih; Acaroğlu, MustafaIn the present day world, where air pollution has reached very high levels, it is known that the pollution caused by motor vehicles is at a level which cannot be ignored. Environmental problems which are caused by carbon monoxide, hydrocarbon, nitrogen compounds and particles emitted from the exhausts of the vehicles have reached serious proportions. The use of LPG, which is one of the light products of petroleum, as a fuel in spark plug ignition engines is another application which will commute the present liquid fuels. Gas fuels are the ones which create the least difficulty in the formation of the mixture, ignition of the distribution and control of burning. Gas fuels are known as the ideal fuels for being less pollutant in terms of exhaust emissions. In the present study, it was aimed to determine the efficient operation conditions of the LPG system elements used in internal combustion engines. The 4th Generation Sequent Gas Phase LPG Injection System, which is at the last point LPG systems have reached, was examined and the system was introduced. A device with 4th Generation Lovato Brand Sequent Gas Phase LPG Injection System was mounted on a 2000 Model Hyundai Accent 1.5 GLS with MPI system, and experiments were conducted on the vehicle. Exhaust emission and vehicle performance values were determined by operating the vehicle on LPG and unleaded gasoline.Öğe Fatigue Behaviour of Surface-Cracked Glass/Polyester Composite Plates(2012) Günaydın Akkuş, Berrin; Dağhan, Behçet; Önal, GürolThis paper reports on the fatigue behaviour of surface–cracked glass/polyester composite plates. The machined cracks have various aspect ratios (a/c) and depth ratios (a/t). The propagation behaviour of surface cracks and delamination are investigated under constant-amplitude (R ¼ 0) loading. The stress intensity factor, KI , is obtained using Newman–Raju and Paris and Sih equations, while Kdel is determined using equations given by Suo and Hutchinson and Bao et al. The results were plotted as curves of the typical relationship between the crack growth rate (dc/dN) and the stress intensity factor range (KI) and the delamination propagation rate (db/dN) and the delamination stress intensity factor range (Kdel). Material constants A and n were obtained according to the Paris–Erdoğan equation.
