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Polen görüntülerinin yapısal özellikler ile sınıflandırılması
(IEEE, 2013) Çalışkan, Abidin; Kaya, Yılmaz; Erez, Mehmet Emre
Bu çalışmada, bitkilere ait polen tanelerini bir uzman kişinin yardımına ihtiyaç duymadan farklı taksonomik kategorilere ayıran bir bilgisayarla görü sistemi geliştirilmiştir. Polen taneleri üç boyutlu karmaşık bir yapıya sahip olmalarına rağmen birbirlerinden ayırt edilebilir özellikler taşırlar. Çalışmada polen görüntülerin sınıflandırılması için yerel kenar örüntüler (YKÖ) kullanılmıştır. Önerilen sistem 3 aşamadan oluşmaktadır. Birinci aşamada polen görüntülerine Sobel kenar algoritması uygulanarak yapısal özelliklerin belirgin olduğu yeni görüntüler elde edilmiştir. İkinci aşamada yeni görüntülerden YKÖ elde edilmiş, son aşamada ise elde edilen özellikler ile makine öğrenmesi yöntemleri ile sınıflandırma işlemi gerçekleştirilmiştir. YKÖ ile %98,48 gibi önemli bir sınıflandırma başarısı elde edilmiştir.
Bazi euphorbia (Euphorbiaceae) tohum türlerinin siniflandirilmasi için yerel ikili örüntüler tabanli bir bilgisayar görü sistemi
(IEEE, 2013) Çalışkan, Abidin; Kaya, Yılmaz; Karabacak, Osman
Bu çalışmada tohum görüntülerin sınıflandırılması için bir bilgisayar görü sistemi önerilmiştir. Sayısal tohum görüntülerinden elde edilen yerel ikili tekdüze örüntüler kullanılarak tohum sınıflandırılması gerçekleştirilmiştir. Çalışmada 240 (120 eğitim ve 120 test) tohum görüntüsü kullanıldı. Öncelikle eğitim setindeki her tohum türü için ortalama tekdüze histogramlar (tohum türü sınıfları) elde edildi. Daha sonra test setindeki her tohum için LBP histogramı üretilip ve tohum türü sınıflarına ait histogramlar ile karşılaştırılarak en yakın komşuluk yöntemi ile sınıflandırma işlemi gerçekleştirildi. Tohum örnekleri arasındaki uzaklıkların hesaplanmasında ise Öklit uzaklığı, hata kareler toplamı, histogram kesişimi ölçütü ve Chi-kare istatistiği kullanıldı. Önerilen yöntem ile tohum görüntülerin %95,83 doğru teşhis edilmiştir. Sonuç olarak tohumların yüzey şekilleri taksonomik ilişkilerin belirlenmesi açısından önemli desen bilgileri barındırdığından bilgisayar görü sistemleri tohum türünün tanımlanmasında önemli avantajlar sağlayacağı öngörülmektedir.
Production of mixed rare earth oxide powder from a thorium containing complex Bastnasite ore
(Journals & Books, 2021-02) Özsaraç, Şafak; Kurşunoğlu, Sait; Hussaini, Shokrullah; Top, Soner; Ichlas, Zela Tanlega; Gökçen, Hasan Serkan; Kaya, Muammer
The production of mixed rare earth oxide powder from a thorium containing bastnasite ore by sulfuric acid bake-water leaching followed by precipitation with oxalic acid and thermal decomposition of the oxalates was investigated. The sulfuric acid baking was performed at 250 °C and the optimum baking time was found to be 3 h. Using deionized water as lixiviant, 92.6% La, 86.8% Ce, 86.9% Pr, 82.3% Nd, 95.4% Th and 31% Y were dissolved from the baked ore at 25 °C after 30 min of leaching. The effect of solid-to-liquid ratio on the dissolution of the rare earth elements and thorium shows that when the solid ratio in the water increased from 1:10 to 1:3, the dissolution percentage decreased. The final mixed rare earth oxide powder contained 88.54% REO and 6% ThO2 together with small amounts of other impurities. The SEM mapping results revealed that the produced REO has an irregular crystal shape. Based on the experimental results obtained from the current study, a flowsheet was proposed for the production of mixed rare earth oxide powder from a specific complex bastnasite ore.
Assessment of heavy metal pollution of urban soils of Batman by multiple pollution indices
(Taylor & Francis, 2021-03-28) Baran, Hacı Alim; Gümüş Kıral, Nurcan
Heavy metal accumulation is observed in urban soils, sometimes due to anthropological effects and sometimes due to natural geological units. In order to determine the heavy metal content of the Upper MioceneLower Pliocene Selmo Formation, which is observed in the whole study area and consists of conglomerate, sandstone and silt stone, soil and river sediment samples were taken. Within the scope of pollution assessment, geo-accumulation index (Igeo), enrichment factor (EF) and pollution index (PI) calculations of Batman urban soil samples were made and different degrees of pollution values were determined. High pollution values were obtained for As, Mo and Sb elements in all pollution indices calculated. The pollution levels of the three elements were determined as strongly to extremely contaminated according to Igeo values, the others except As (very severe enrichment) according to EF values were determined as severe enrichment, and according to PI, all three were determined as strong polluted. Pollution and element distribution maps were created with a geographical information system software. According to the results of correlation analysis and cluster analysis, the elements found to be contaminated are divided into two groups, whose locations and sources of contamination are different. The first group (Sn, Zn and Pb) is observed in the approximate centre of the study area and developed due to traffic emissions. The elements belonging to the second group (especially As, Mo and Sb) show high pollution values in the south-southeast of the study area. These pollutions are thought to be caused by the inadequate storage of mineral oils and batteries that are changed in the industrial site and from leaks in the oil production, storage, refining and transmission phase in TPAO, TÜPRAŞ and BOTAŞ. The analysed samples were compared with the Soil Pollution Control Regulation and WHO standards, and Co, Ni and As element values were found to exceed the permissible values for health
Geochemical features of the Menteşe Formation dolostones (Rhaetian) in the Karacahisar-Kasımlar area (Isparta-Turkey)
(SpringerLink, 2018-08) Dinç, Salih; Özkan, Ali Müjdat
The purpose of this study is to determine the geochemical characteristics of the Menteşe dolostones (Rhaetian) in the west Taurus Mountains, Turkey. The isotope characteristics of the Menteşe dolostones show a variation in the δ18O values of the dolomites between + 1.35 and − 2.72‰ (VPDB) and a variation in the δ13C values of the dolomites between + 1.6 and + 3.33‰ (VPDB). Most of the Menteşe dolostone samples have positive oxygen isotope values; others have weak negative isotope values, which indicate early diagenetic development. In addition, oxygen, carbon, and strontium isotopes and trace element analyses suggest that these dolostones were probably resulted from insignificant recrystallizaion process than chemically similar fluids. Furthermore, Mn/Sr values of the Menteşe dolostones indicate that there is no significant diagenetic alteration. The total REE contents of the Menteşe Formation dolostones display a strong positive correlation with Si, Al, Fe, K, Ti, Ba, Rb and negative correlation with Mg, hence REE content is associated with in the first degree titanium-bearing minerals (probably sphene, rutile, anatase), second degree phosphate (apatite), and barium and rubidium-bearing minerals (probably barite). Ce anomalies versus Nd concentrations of the Menteşe dolostone samples indicate that these dolostones are formed in an anoxic environment. In addition, the K/Rb ratios of the Menteşe dolostones are not exposed to any metamorphism and indicate some diagenetic alteration. Calculated temperature values using δ18O values of the Menteşe dolostones yield precipitation temperatures of 17 to 42 °C, and suggest burial depths of 67 to 900 m. Sources of magnesium for dolomitization of the Menteşe Formation carbonates were most likely fluids from seawater and/or diagenetic brines (slightly modified seawater). The Menteşe dolostones formed as early diagenetic (Rhaetian to Cenomanian) in shallow burial areas at lower temperatures than seawater and/or diagenetic brines (slightly modified seawater).
Measuring the sediment thickness in urban areas using H/V spectral ratio method in Batman region, Southeast Turkey
(SpringerLink, 2021-02-03) Dinç, Salih; Alpaslan, Nuray; Yılmaz, Salim
In this study, microtremor records measured with a 3-component seismometer in Batman city center, which was established on the plain, were evaluated for the geological structure of the region and soil forming units. The measurements obtained from the field survey were evaluated with the Geopsy program by using the horizontal/vertical spectral ratio (Nakamura 1989) and the geological condition of the area and soil dominant frequency were determined. Soil characteristics of Batman City, which is geologically located on a plain, was evaluated by finding the loose units in the site with the map consisting of shear wave velocities (VS) found by applying the T = Σ4Hi /Vsi formula of Kanai (1983), which was developed for the soft soil layer on the bedrock, to the dominant frequency values (F0) obtained from the microtremor measured and soil classes corresponding to these values; and depth (H) and shear wave velocities (VS) were found by applying Formula (6) and the soil classes corresponding to these values. The dominant frequency at the measurement points and the lithology of the soil forming units were evaluated together to create dominant frequency maps of the region, and the relationship between the geology of the region and obtained microtremor measurements was discussed.
Second Law analysis in concentric heat exchangers with vortex flow generators
(Energy Education Science and Technology, 2011) Argunhan, Zeki; Çakmak, Gülşah; Yıldız, Cengiz; Behçet, Rasim
In the present study, the experimental results of heat transfer of a concentric tube heat exchanger were analyzed with respect to Second Law of Thermodynamics to reach the geometric optimal design of the heat exchangers. In order to increase the heat transfer, the vortex generators were placed in the entrance of the inner pipe of the heat exchanger. These vortex generators are 60 mm in diameter having six angled (55°, 65°, 75°, 90°) winglets. The winglets have one rectangular slot in each and are 2×7 mm in dimensions. Experiments were carried out with different Reynolds Numbers. Air as hot fluid and water as cold fluid were passed through the inner pipe and outer pipe of the concentric tube heat exchanger, respectively. The variations of the efficiency and Entropy Generation Number with respect to Reynolds Number are shown in graphics, and the results were discussed.
Experimental investigation of the effects of diesel-like fuel obtained from waste lubrication oil on engine performance and exhaust emission
(Journals & Books, 2010-10) Argunhan, Zeki; Yumrutaş, Recep; Arpa, Orhan
In this study, effects of diesel-like fuel (DLF) on engine performance and exhaust emission are investigated experimentally. The DLF is produced from waste engine lubrication oil purified from dust, heavy carbon soot, metal particles, gum-type materials and other impurities. A fuel production system mainly consisting of a waste oil storage tank, filters, a reactor, oil pump, a product storage tank, thermostats and control panel is designed and manufactured. The DLF is produced by using the system and applying pyrolitic distillation method. Characteristics, performance and exhaust emissions tests of the produced DLF are carried out at the end of the production. The characteristic tests such as density, viscosity, flash point, heating value, sulfur content and distillation of the DLF sample are performed utilizing test equipments presented in motor laboratory of Mechanical Engineering Department, University of Gaziantep, Turkey. Performance and exhaust emission tests for the DLF are performed using diesel test engine. It is observed from the test results that about 60 cc out of each 100 cc of the waste oil are converted into the DLF. Characteristics and distillation temperatures of the DLF are close to those values of a typical diesel fuel sample. It is observed that the produced DLF can be used in diesel engines without any problem in terms of engine performance. The DLF increases torque, brake mean effective pressure, brake thermal efficiency and decreases brake specific fuel consumption of the engine for full power of operation.
The effect of rotary type turbulator placed in entrance of heat exchanger on heat transfer and frictional loss
(Energy Education Science and Technology, 2011) Argunhan, Zeki; Behçet, Rasim; Yakut, Ali Kemal
In this study, improving heat transfer in heat exchangers with paralel flow is gained by using swirl flow. For this purpose, a propeller type of turbulator was placed in the entrance of interior pipe of heat exchanger with paralel flow and the effect of turbulator on the heat transfer and friction losses in steady conditions was experimentally investigated. The effect of production of turbulance for improvement of heat transfer in interior pipe flows and the effects of turbulator on heat transfer and pressure drop are experimentally researched by placing a propeller type of turbulator at the entrance of heat exchanger to produce swirl air flow. In experiment setup, water was used as the fluid on which the heat was transferred and air was used as the fluid from which heat was transferred to the water. By usage of datas obtained from experimental measurements were calculated for Reynolds number ranging from 8000 to 24000 necessary relationships effet on heat transfer and pressure drop. In comparison with empty pipe it was seen that the heat transfer increased at range between 25,5%- 50,3% and the friction losses increased 5 times. Besides, by analyzing the system exergy, the dependence of non-dimensional exergy loss on Reynolds number was drawn to investigate whether this improvement technique is advantageous thermodynamically or not. When comparing the exergy losses in empty pipe and the pipe with a turbulator at approximately same Reynolds numbers, it was seen that exergy loss is 15% higher for empty pipe than that for the pipe with the turbulator. As a result of that information, the improvement technique was proved to be advantageous in thermodynamic manner too. By the usage of turbulator that results in the partial recovery of loss energy, it was proven that the improvement technique was thermodynamically advantageous
Dimension and insulation thickness optimization of circular flat plate solar collectors
(Energy Education Science and Technology, 2011) Argunhan, Zeki
In this study, expressions for optimum radius of a circular flat plate solar collector and the optimum insulation thickness distribution are derived by using the concept of solar gain, which maximizes the life-cycle savings. For the specified condition the optimum radius has been found as 2.14 m and the optimum insulation thickness distribution on back of collectors has been formulized. The insulation material thickness distribution has been determined by performing a detailed dimensional analysis; therefore heat loss is minimized, and results are presented in graphics.
Effect of swirl generators with different sized propeller on heat transfer enhancement
(Energy Education Science and Technology, 2011) Argunhan, Zeki; Yıldız, Cengiz; Çakmak, Gülşah
In this study, the swirl flow that is one of the passive methods is used for increasing the heat transfer coefficient in the concentric heat exchangers. For this purpose, propeller type swirl generators were prepared to test in the experiments. So, the effect of propellers placed in the inner pipe of the concentric heat exchangers on the heat transfer and pressure drop was investigated experimentally. Experiments were undertaken for the Reynolds Number range of 4000-12000 and for both parallel and counter-flow. It is shown that, the propellers rotated freely with the effect of fluid flowed in the inner pipe are swirling flow generator and they have improved heat transfer. In addition that up to 50% enhancements could be accomplished in heat transfer rates with the swirl generators compared to without the swirl generators. In the parallel flow mode, the enhancement was 10% lower than that of counter-flow at the same Reynolds number. On the other hand the pressure losses increase approximately 3 times more than the empty tube related to Reynolds numbers and propeller sizes. As an outcome of the study, the results showed that a rather smaller size but the same capacity heat exchanger could be proposed by using these elements imposing swirling to the fluid flowing through inner pipe.
Evaluation of fly ash and polypropylene in production of composite materials
(Energy Education Science and Technology, 2012) Argunhan, Zeki; Yıldız, Tülay; Haksever, Aysen
More than 10 million tons of fly ash produced in power plants and polypropylene wastes cause environmental pollution in Turkey. Not only the environmental problems they create, but also the fact that demand for raw material sources increases rapidly make fly ashes and waste polypropylene necessary to be researched. In this study the usability of the fly ashes and polypropylene wastes of Soma and Afsin-Elbistan Power Plants in producing new composite materials has been investigated. Materials which possess new properties such as composite type isolation have been formed by melting down the polypropylene wastes that are used as combining elements and by mixing this with fly ash in different percentages. The thermal conductivity, endurance against pressure pull-corrosion, and the rates of water absorption of these materials were analyzed experimentally and both stated and interpreted in the graphics. By this way, these two materials can be recovered by both lessening the environmental problems and providing income for economy by means of saving energy.
Experimental investigation of thermal performance in a concentric tube heat exchanger with wavy inner pipe
(SpringerLink, 2012-06) Argunhan, Zeki; Çakmak, Gülşah; Yücel, Halit Lutfi; Yıldız, Cengiz
In this article, the heat transfer, friction factor, and thermal performance factor characteristics of a concentric-tube heat exchanger are examined experimentally. A wavy inner pipe is mounted in the tube with the purpose of generating swirl flow that would help to increase the heat transfer rate of the tube. The examination is performed for a Reynolds number ranging from 2700 to 8800. An empirical correlation is also formulated to match with experimental data of the Nusselt number using the Wilson plot method. In addition, to obtain the real benefits in using the swirl generator at a constant pumping power, the thermal enhancement factor is also determined. Over the range considered, the increases in the Nusselt number, friction factor, and thermal performance factor are found to be, respectively, about 113 %, 81 %, and 196 % higher than those obtained from a smooth-surface inner pipe.
Effect of the air flow rate of blower on the performance of solar still
(Türk Isı Bilimi ve Tekniği Derneği, 2015-06-01) Argunhan, Zeki; El, Emin; Yücel, Halit Lutfi; Çakmak, Gülşah; Yıldız, Cengiz
Solar distillation is one of the important methods for water purification. This paper examines the performance of solar distillation system at different air flow rate. To increase the performance of distiller, artificial wind was created by fan and suitable wind speed was investigated to increase the amount of water distilled. The experiments were carried out in Elazığ climate conditions. In order to examine the effect of the wind speed on solar distillation system, two stills were manufactured with the size of 1000x1000 mm. One of them was the conventional still which was used as a reference. The other still was used to investigate experimentally the effect of the wind speed. Graphs were drawn for time-dependent changes in the amount of water distilled. It was found that that the productivity of the fan-still distiller was 14.7 % greater than that of a conventional still.
Experimental investigation of solar stills integrated with solar water heating collectors
(Türk Isı Bilimi ve Tekniği Derneği, 2017-10-31) Argunhan, Zeki; El, Emin; Yıldız, Cengiz; Çakmak, Gülşah
Solar still is a more practical way of obtaining clean water. In this study, we aimed to improve the efficiency of solar still systems and obtain distilled water at the same time. For this purpose, 5 different solar still systems were designed. Type 1; conventional solar still, Type 2; conventional solar still integrated with solar water heating collector and run via natural convection, Type 3; conventional solar still integrated with solar water heating collector and tubular heat exchanger and run via natural convection, Type 4; conventional solar still placed with plate heat exchanger and integrated with solar water heating collector and run via natural convection, Type 5; conventional solar still placed with plate heat exchanger and integrated with solar water heating collector and run via forced convection. In this study, the experiments were carried out on the parameters influencing the performance, the amount of distilled water obtained, and the efficiency of experiment settings designed in different types; and finally the results were presented. The amount of distilled water and efficiency of conventional solar still were 2389 ml and 51.47%, respectively. Maximum total amount of water and efficiency from natural convection systems were obtained from Type 4, and the values calculated were found as to be 5788 ml and 55.91%. Maximum amount of distilled water and the efficiency were obtained by utilizing forced convection system were found as to be 6068 ml and 58.99%, respectively.
Microstructure and mechanical properties of armor 500/AISI2205 steel joint by friction welding
(Journals & Books, 2017-08) Batı, Serkan; Kırık, İhsan; Sarsılmaz, Furkan
This paper discussed the properties of friction welded joint of Armor 500 steel and duplex (ferritic/austenitic) steel AISI 2205 and compared the properties of weld at different welding parameters. The experimental study was conducted with the welding parameters such as friction pressure and friction time. The experimental results indicated that armor 500 steel could be joined to AISI 2205 steel using the traditional friction welding technique. The processed joints were tested through axial tension test. In addition, the highest tensile strength, which is 1020 MPa is obtained when friction time is 8 s and friction pressure is 80 MPa. The microstructures of the alloys and fracture surfaces were examined by optical and scanning electron microscopy. Experimental results indicate that microstructural and mechanical properties are significantly affected by changing welding parameters within the chosen range of conditions.
Effect of Cu addition on porous NiTi SMAs produced by self-propagating high-temperature synthesis
(De Gruyter, 2019-12) Batı, Serkan; Kılıç, Musa; Yenigün, Burak; Balaban, Zülküf; Kırık, İhsan
The focus of the study is on the effect of copper addition on the porosity, microstructure and mechanical properties of hot pressed NiTi and NiTiCu shape memory alloys (SMAs), ignited by means of self-propagating high-temperature synthesis (SHS). Optical microscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive spectrometry (EDS), hardness tests and compression tests were applied respectively to determine the microstructure and mechanical behavior of the samples. The experimental results show that the addition of Cu into NiTi SMAs increases porosity and microhardness but also reduces compressive strength.
Correlation formulation for optimum tilt angle for maximizing the solar radiation on solar collector in the Western Himalayan region
(Journals & Books, 2021-01) Kallioğlu, Mehmet Ali; Sharma, Ashutosh; Awasthi, Anchal; Chauhan, Ranchan; Fekete, Gusztáv; Singh, Tej
Solar tracking devices are efficacious in maximizing solar irradiation collection. However, higher price makes these systems less frequently used. As an alternative, optimum tilt angle estimation has the advantage that it does not involve tracking cost expenditure. In this study, optimum tilt angles for different months have been computed for Hamirpur, Himachal Pradesh, India (L 31° 42′ N). Several mathematical models and statistical tools have been employed to forecast the monthly optimum tilt angles for the selected site. Different scenarios have been presented by considering five, four, three, and two annual adjustment models to increase the practical usage of the estimated optimum tilt angles. Additionally, cost-benefit analysis has also be performed on the PV panels. Based on the results, it has been concluded that model M − 11, with three annual adjustments, stipulates maximum benefits over the other models. This study can serve as fundamental guidance for setting up solar energy plants in this specified region with the highest efficiency.
Progressive failure analysis in adhesively, riveted, and hybrid bonded double-lap joints
(Taylor & Francis, 2013-11) Topkaya, Tolga; Solmaz, Murat Yavuz
One of the important processes in structural design is the joining technique. Failure of composite joints involves different failure mechanisms depending upon the joining technique. In this study, a progressive failure analysis was performed on adhesively, riveted, and hybrid bonded double-lap joints. In the joints, a woven-type fiberglass-reinforced composite material was used as the main material; AV 2015 was used as the adhesive, and steel as the rivet material. The analyses were performed using ANSYS 12.1 finite element package software via software written using parametric design language (APDL) codes. At the end of the progressive failure analysis, failure loads and failure modes were determined for 30-, 45-, and 60-mm overlap lengths in accordance with the Maximum Shear Stress Theory and Hashin Criteria. For 45-mm overlap lengths, the joint strength of hybrid joints proved to be 2.72 and 1.145 times higher, respectively, than adhesive and fastening joints. Results showed that the failure load of the joint increased when the overlap length increased. In riveted joints, the failure occurring in the composite plates began around the rivet hole and the catastrophic failure of these types of joints resulted from fiber tensile failure.
Numerical analysis of the effect of implant geometry to stress distributions of the three different commercial dental implant system
(Sivas Cumhuriyet Üniversitesi, 2015-02-11) Topkaya, Tolga; Solmaz, Murat Yavuz; Dündar, Serkan; Eltas, Abubekir
Objectives: The success of dental implants is related to the quality, quantity of local bones, implant design and surgical technique. Implant diameter and length are accepted as key factors. Present work focuses to investigate the effect of titanium implant geometry to stress distributions in implant system. Materials and Methods: For this purpose three different implant models which are currently being used in clinical cases constructed by using ANSYS Workbench 12.1. The stress distributions on components of implant system under static loadings were analyzed for all models. Results: The maximum stress values that occurred in all components happen in the case of loading in which the Nucleoss T-4 (Nucleoss, Turkiye) implant is used, but the occurred lowest stress values happen in the case of Fı loading in which Nobel Active (Nobel Biocare, Zurich, Switzerland) implant is used. In all models, the maximum tensions have occurred in the neck region of the implants. Conclusions: The crestal bone loss in the neck region of the implants reduced the long-term survival rate of implants.The length and the size of the implant are the two important factors in the stress distribution.

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