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Experimental and Statistical Investigation of the Machinability of Al-10% SiC MMC Produced by Hot Pressing Method
(Springer Heidelberg, 2014) Ekici, Ergün; Samtaş, Gürcan; Gülesin, Mahmut
In this study, during the machining of metal matrix composites produced by a hot pressing method in CNC milling, the effects of cutting parameters and coating type on the surface roughness were experimentally and statistically investigated. The production of composite samples was accomplished by hot pressing, in which Al was used as the matrix element and 10 % SiC particles were chosen for the reinforcing phase. In the machining of samples, three different cutting tools (uncoated, multi-layered and Nano TiAlN coated), three different cutting speeds (60, 78, 101 m/min) and three different feed rates (0.04, 0.08 and 0.12 mm/rev) were employed. Full factorial (3(3)) experimental design was chosen for the statistical investigation of the cutting parameters and parameter interactions. The response surface method was used in the mathematical modelling of the surface roughness obtained from the experiments and in the optimisation of cutting parameters. At the end of the study, the cutting tool's wear was evaluated and the wear was discussed by comparison with similar studies.
Electrical and Dielectric Properties of a n-Si Schottky Barrier Diode with Bismuth Titanate Interlayer: Effect of Temperature
(Springer, 2017) Yıldırım, Mert; Şahin, C.; Altındal, Şemsettin; Durmuş, Perihan
An Au/Bi4Ti3O12/n-Si Schottky barrier diode (SBD) was fabricated with a 51 nm Bi4Ti3O12 interfacial layer. Admittance measurements of the fabricated SBD were carried out in the bias voltage (V) range of -4 V and 6 V. Capacitance (C) and conductance (G/omega) measurements were carried out in a wide temperature range of 120-380 K so that temperature effects on electrical and dielectric properties of the SBD were investigated. Main electrical parameters were extracted from reverse bias C (-2)-V plots. It was found that variance of electrical and dielectric parameters of the SBD with temperature is basically different for low and high temperature regions. A fair number (similar to 10(12) eV(-1) cm(-2)) was obtained for surface states (N (ss)); however, N (ss) first decreased then increased with temperature. This result was associated with increased defects with temperature and higher activation energy in the high temperature region. Dielectric parameters of the SBD were also extracted and the dielectric constant of SBD was found as similar to 10 at room temperature. Application of modulus formalism to the admittance data revealed temperature-activated dielectric relaxation at 340 K. Results showed that the temperature has considerable effects on electrical and dielectric properties of Au/Bi4Ti3O12/n-Si SBD.
Effects of Frequency and Bias Voltage on Dielectric Properties and Electric Modulus of Au/Bi4Ti3O12/n-Si (MFS) Capacitors
(Gazi Univ, 2017) Durmuş, Perihan; Bilkan, Çiğdem; Yıldırım, Mert
In this work, a metal-ferroelectric-semiconductor (MFS) type capacitor was fabricated and admittance measurements were held in a wide frequency range of 1 kHz-5 MHz at room temperature for the investigation of frequency and voltage dependence of complex dielectric constant, complex electric modulus and electrical conductivity of the MFS capacitor. Bismuth titanate (Bi4Ti3O12) with high dielectric constant was used as interfacial ferroelectric material and the structure of MFS capacitor was obtained as Au/Bi4Ti3O12/n-Si. Experimental results showed that dielectric, modulus and conductivity parameters are strong functions of frequency and voltage especially in depletion and accumulation regions due to the existence of surface states (N-ss), series resistance (R-s), interfacial polarization and interfacial layer. It was found that R-s of the structure and interfacial ferroelectric layer are efective in accumulation region whereas surface states (N-ss) and interfacial polarization are efective in depletion region. Also the changes in dielectric, modulus and conductivity parameters become considerably high particularly at low frequencies due to high values of R-s and N-ss. The observed anomalous peak in voltage dependent plots of capacitance and dielectric constant was atributed to the particular density distribution of N-ss, R-s and minority carrier injection. Moreover, the value of conductivity at low and intermediate frequencies is almost independent of frequency thus low frequency data was used to extract d.c. conductivity. This work showed that the use of high-dielectric Bi4Ti3O12 as ferroelectric interfacial layer in a MFS capacitor is preferable due to high values of its dielectric constant compared with traditional insulator layer materials such as SiO2 and SnO2. Therefore, a MFS capacitor with Bi4Ti3O12 interfacial layer can store more energy thanks to its high dielectric constant.
Effect of iron phthalocyanine (FePc) concentration on electrical and dielectric properties of the nematic liquid crystal composites
(Elsevier Science Bv, 2016) Yıldırım, Mert; Köysal, Oğuz; Önsal, Gülnur; Gümüş, Eren
Electrical and dielectric properties of iron phthalodyanine (FePc) dispersed E63 nematic LC were investigated using admittance measurements in the frequency range of 100 Hz - 20 MHz and current measurements in the bias range of 0-20 V. In order to observe the effect of FePc concentration, E63 was dispersed with 1,3 and 5% wt/wt FePc. Basic dielectric parameters such as dielectric anisotropy (Delta epsilon), crossover frequency (f(c)); real and imaginary parts of dielectric permittivity (epsilon' and epsilon") and relaxation time (tau) of the samples were obtained from the (sigma(ac) sigma(dc)). experimental data, along with threshold voltage (V-th), splay elastic constant (K-11) and conductivity parameters (sigma(ac) sigma(dc)). Dispersal of FePc and its concentration caused V-th, K-11, sigma(dc), and f(c) of the LC composites increase whereas tau is lowered. LC composites were found to exhibit relaxation in low and high frequency regions such that the former was masked due to high conductivity in the samples and hence electric modulus formalism was applied to determine low frequency relaxation. Prominent effect of FePc dispersal was found in sigma(dc) values in a way that sigma(dc) of the LC composite of E63 with 5% wt/wt FePc is about 53 times larger than that of neat E63. (C) 2016 Elsevier B.V. All rights reserved.
Diode-to-diode variation in dielectric parameters of identically prepared metal-ferroelectric-semiconductor structures
(Elsevier Science Sa, 2017) Çetinkaya, H.G.; Yıldırım, Mert; Durmuş, Perihan; Altındal, Şemsettin
In this research, a total number of 58 diodes were fabricated in the form of Al/Bi4Ti3O12/p-Si structure and the voltage dependence of the real and imaginary parts of the complex dielectric constant (epsilon' and epsilon") and complex electric modulus (M' and M'') and ac electrical conductivity (sigma(ac)) of these diodes were investigated. It was also aimed to determine whether or not these parameters change from one sample to another and what kind of distribution exists for the identically fabricated samples. Mentioned parameters (e', e'', M', M'' and sac) were calculated using the capacitance and conductance data that were measured between -4 V and 4 V at 500 kHz at room temperature. Experimental results show that all of these parameters are strong functions of applied bias voltage especially in the depletion and accumulation regions. These changes are results of the restructuring and reordering of the surface states and their relaxation time under external electric field. Besides, it was found that there is diode-to-diode variation among the values of dielectric parameters which revealed double Gaussian distribution for the total 58 diodes. Thus, the results confirmed that investigating these parameters only for a single sample at a single bias voltage value cannot supply enough information on the dielectric properties and electric modulus. Therefore these parameters must be calculated in the wide range of bias voltage even for the identically prepared samples on the same semiconductor wafer. (C) 2017 Elsevier B.V. All rights reserved.
Design of grippers for laparoscopic surgery and optimization of experimental parameters for maximum tissue weight holding capacity
(Polska Akad Nauk, Polish Acad Sci, Div Iv Technical Sciences Pas, 2019) Ertürk, Sinem; Samtaş, G.
Grippers are routinely used to hold, lift and move organs in laparoscopic operations. They are generally toothed to prevent organs from slipping during retention. Organs held by grippers are always at risk of being damaged by the clamping force. In this study, noncontact grippers working with the Bernoulli principle and using air pressure were developed, and vacuum performance was compared in terms of maximum tissue weight holding capacity. For this purpose, Taguchi method was employed for experimental design and optimization, and Taguchi L-16 orthogonal array was selected for experimental design. The experimental parameters were 4 gripper types, 4 air-pressure levels (3.5, 4.5, 5, and 5.5 bar), 4 flow rates (2.2, 2.6, 2.8 and 3 m(3)/h) and two animal tissue types (ventriculus/gizzard and skin). Values from the experimental procedures were evaluated using signal-to-noise ratio, analysis of variance and three-dimension graphs. An equation was obtained by using 3rd-order polynomial regression model for weight values. Optimization reliability was tested by validation tests and the revealed test results were within the estimated confidence interval. The results obtained from this study are important for future studies in terms of organ injury prevention due to traditional grippers in laparoscopic surgery.
Design and Experimental Investigation of Pneumatic Movement Mechanism Supported by Mechanic Cam and Crank Shaft
(Assoc Information Communication Technology Education & Science, 2015) Korucu, Salih; Samtaş, Gürcan; Soy, Gürkan
The pressurized air is applied to many sectors required purity and velocity. One of these sectors is to use of air as impulsive force in the moving mechanisms. In this study, the movement mechanism prototype worked with compressed air was designed and produced forlight vehicle engine as motorbike and ATV (All-Terrain Vehicle). In developed mechanisms, pneumatic artificial muscles were used for a given movement of crankshaft. A cam system was also designed for synchronization pneumatic muscles. In this way, these muscles transmit the synchronous movement to crankshaft. At the end of the study, the developed mechanism was mounted on an ATV vehicle(110 cc/ Cubic Centimeter, engine displacement capacity) and its performance was tested using the four different weights (50, 75, 100 and 150 kg), three different pressures (4, 5 and 6 bar) and two different hoses (empty set 6 and empty set 8 mm). By considering experimental results and design criteria, power of the movement mechanism was obtained as 886 Watt. With this study, minimization of energy consumption for movement of passenger cars, and using clean and cheap energy as ATV which can be alternative for single or two passenger vehicles.
Current conduction and steady-state photoconductivity in photodiodes with bismuth titanate interlayer
(Elsevier Science Sa, 2016) Yıldırım, Mert
Bismuth titanate, Bi4Ti3O12 (BiT), has proven to be a suitable candidate for electro-optical applications, therefore present study aims to report its utility as a photodiode material through current conduction and steady-state photoconductivity investigations. For this purpose, Al/p-Si diodes having thin film BiT interlayer (10 and 25 nm) were fabricated and current-voltage measurements were held in dark and under illumination. Among the samples, better current-voltage characteristics were obtained for the sample with 10 nm BiT interlayer. Deposition of BiT interlayer modified the current conduction mechanism in the forward bias region and interface-limited injection was reported for the diodes with BiT interlayer in the high forward biases. Variation of photocurrent with illumination intensity suggested a supralinear recombination process for the samples with BiT interlayer. High responsivity (2.891 A/W) and photosensitivity (7318.7) values were obtained for the sample with 10 nm BiT interlayer at 250 mW/cm(2) illumination intensity. Obtained results suggest that BiT interlayer (10 nm) can be utilized for visible light photodiode and photosensor applications. (C) 2016 Published by Elsevier B.V.
Current conduction in Schottky barrier diodes with poly(propylene glycol)-b-polystyrene block copolymer interfacial layer
(Natl Inst Science Communication-Niscair, 2017) Yıldırım, Mert; Allı, Abdulkadir; Demir, Ahmet; Allı, Sema; Gökçen, Muharrem
Polymeric materials have gained great importance in electron devices. There has been considerable number of studies on block copolymers due to enhanced features that appear after co-polymerization. In this study, poly (propylene glycol)-b polystyrene block copolymer has been synthesized and Schottky bather diodes (SBDs) have been fabricated with this block copolymer. Current-voltage (I-V) measurements have been conducted at room temperature in order to investigate electrical characteristics and current conductions governing in these SBDs. Series resistance and shunt resistance of the SBDs have been calculated using Ohm's law. Ideality factor, reverse saturation current and zero-bias bather height of the SBDs have been extracted from the forward-bias I-V data. Fabricated SBDs exhibited high rectifying ratio of the order 10(4). Also, current conduction mechanisms and the density of interface states in the SBDs have been investigated. Calculated values of density of interface states in the SBDs are on the order of 10(13) which is acceptable for this kind of SBDs having polymeric interfacial layer.
Synthesis & chemical and dielectric characterization of poly (linoleic acid)-g-poly (dimethylaminoethyl methacrylate): A novel high-kappa graft copolymer
(Elsevier Sci Ltd, 2017) Yıldırım, Mert; Allı, Abdulkadir; Önsal, Gülnur; Gök, Neslihan; Köysal, Oğuz
In this study, poly (linoleic acid)-g-poly (dimethylaminoethyl methacrylate) (PLina-g-PDMA; PLDMA) graft copolymer was obtained from polymeric linoleic acid peroxide (PLina) possessing peroxide groups in the main chain by free radical polymerization of 2-dimethylaminoethyl methacrylate (DMA). Synthesized graft polymer, i.e. PLDMA, was first characterized chemically through proton nuclear magnetic resonance (H-1 NMR), differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA) and differential thermal analysis (DTA) and elemental analysis (EA) techniques. Later, PLDMA was injected into ITO coated glass cell and its electrical and dielectric measurements were carried at room temperature between 3 Hz and 3 MHz. PLDMA revealed dielectric constant (epsilon') values on the order of 10(3) below 1 kHz. Therefore, having such high dielectric constant value, PLDMA was proposed as high-kappa dielectric material with epsilon' = 6141 at 3 Hz. Dielectric relaxation of the polymer was characterized using Cole-Cole plots. Investigation of electrical conductivity of PLDMA yielded dc conductivity as 36774 S/cm. Moreover, PLDMA was further dispersed with CdTe quantum dots to explore its utility for hybrid composites and effects of quantum dot dispersal on electrical and dielectric parameters were also investigated. (C) 2017 Elsevier Ltd. All rights reserved.
Optimization of cutting parameters in pocket milling of tempered and cryogenically treated 5754 aluminum alloy
(Polska Akad Nauk, Polish Acad Sci, Div Iv Technical Sciences Pas, 2019) Samtaş, Gürcan; Korucu, Salih
Aluminum alloys are widely used today in plastic injection molds in the automotive and aerospace industries due to their high strength and weight ratio, good corrosion and fatigue resistance as well as high feed rates. The 5754 aluminum alloy has high corrosion resistance and a structure suitable for cold forming. In this study, an AA 5754-H111 tempered aluminum alloy with the dimensions of 80x80x30 mm was used, and some of the materials were cryogenically heat treated. For the milling operations, phi 12 mm diameter 76 mm height uncoated as well as TiCN and TiAlN coated end mills were used. Different levels of cutting depth (1.25, 2.0, 2.5 mm), cutting speed (50, 80, 100 m/min), feed rate (265, 425, 530 m/min) and machining pattern (concentric, back and forth and inward helical) were used. The number of experiments was reduced from 486 to 54 using the Taguchi L-54 orthogonal array. The values obtained at the end of the experiments were evaluated using the signal-to-noise ratio, ANOVA, three-dimensional graphs and the regression method. Based on the result of the verification experiments, the processing accuracy for surface roughness was improved from 3.20 mu m to 0.90 mu m, with performance increase of 71.88%.
Optimization of Cutting Parameters for Surface Roughness in Milling of Cryogenic Treated EN AW 5754 (AlMg3) Aluminum Alloy
(Gazi Univ, 2019) Samtaş, Gürcan; Korucu, Salih
Aluminum alloys are now widely used in plastic injection molds in the automotive and aerospace industries due to their high strength and weight ratio, good corrosion and fatigue resistance. In this study, EN AW 5754 (AlMg3) 5754 aluminum alloy with dimensions of 80x80x30 mm was subjected to cryogenic treatment, face milling was performed with coated and uncoated inserts, and then the effects of cutting parameters on surface roughness during face milling were examined. The experiments were conducted with Taguchi L-9 orthogonal array, using three different cutting inserts (Al2O3-TiCN-TiN coated, TiAlN coated Nano, TiB2 coated), cutting speeds (310, 450, 600 m / min), feed rates (0.15, 0.25, 0.35 mm / tooth) and depths of cut (0.5, 1, 1.5 mm). The values obtained at the end of the experiments were evaluated using signal-to-noise ratio (S/N), variance analysis (ANOVA), three-dimensional graphs and regression method. Taguchi analysis has revealed that optimum cutting conditions for the minimum surface roughness are the Al2O3-TiCN-TiN coated insert, 1 mm depth of cut, 600 m/min cutting speed and 0.15 mm/tooth feed rate. The surface roughness values for these cutting conditions were found as 0.47 mu m in the calculations and 0.32 mu m in the verification experiments.
On the possible conduction mechanisms in Rhenium/n-GaAs Schottky barrier diodes fabricated by pulsed laser deposition in temperature range of 60-400K
(Springer, 2019) Durmuş, Haziret; Yıldırım, Mert; Altındal, Şemsettin
AbstarctThis study presents electrical characteristics of n-GaAs based Schottky barrier diodes (SBDs) with Rhenium (Re) rectifier contacts. The electrical characteristics of the Re/n-GaAs SBDs were investigated utilizing the forward bias current-voltage (I-F-V-F) data collected in temperature range of 60-400K. The values of ideality factor (n) and zero-bias barrier height (phi(Bo)) were found as 9.10 and 0.11eV for 60K, and 1.384 and 0.624eV for 400K, respectively, on the basis of thermionic-emission theory. The conventional Richardson plot deviated from linearity at low temperatures and the Richardson constant value (A(*)) was obtained quite lower than the theoretical value for this semiconductor (8.16Acm(-2)K(-2)). nkT/q-kT/q plot shows that the field-emission may be dominant mechanism at low temperatures as a result of tunneling via surface states since the studied n-GaAs's doping concentration is on the order of 10(18) cm(-3), i.e. at high values so leads to tunneling. On the other hand, phi(Bo)-n, phi(Bo)-q/2kT and (n(-1)-1)-q/2kT plots exhibit linearity but this linearity is observed for two temperature regions (60-160K and 180-400K) due the presence of double Gaussian distribution (GD) of the barrier height. Therefore, the standard deviation value was obtained from the plot of phi(Bo)-q/2kT and it was used for modifying the conventional Richardson plot into the modified Richardson plot by which the values of mean barrier height and A(*) were obtained as 0.386eV and 15.55Acm(-2)K(-2) and 0.878eV and 8.35Acm(-2)K(-2) for the low and high temperature regions, respectively. As a result, I-F-V-F-T characteristics of the Re/n-GaAs SBDs were successfully elucidated by double-GD of barrier height.
Measurement and evaluation of surface roughness based on optic system using image processing and artificial neural network
(Springer London Ltd, 2014) Samtaş, Gürcan
The traditional devices, used to measure the surface roughness, are very sensitive, and they are obtained by scratching the surface of materials. Therefore, the optic systems are used as alternatives to these devices to avoid the unwanted processes that damage the surface. In this study, face milling process was applied to American Iron and Steel Institute (AISI) 1040 carbon steel and aluminium alloy 5083 materials using the different tools, cutting speeds and depth of cuts. After these processes, surface roughness values were obtained by the surface roughness tester, and the machined surface images were taken using a polarise microscope. The obtained images were converted into binary images, and the images were used as input data to train network using the MATLAB neural network toolbox. For the training networks, log-sigmoid function was selected as transfer function, scaled conjugate gradient (SCG) algorithm was used as training algorithm, and performance of the trained networks was achieved as an average of 99.926 % for aluminium alloy (AA) 5083 aluminium and as an average of 99.932 % for AISI 1040 steel. At the end of the study, a prediction programme for optical surface roughness values using MATLAB m-file and GUI programming was developed. Then, the prediction programme and neural network performance were tested by the trial experiments. After the trial experiments, surface roughness values obtained with stylus technique for the carbon steel and aluminium alloy materials were compared with the developed programme values. When the developed programme values were compared with the experimental results, the results were confirmed each other at a rate of 99.999 %.
Low-cost variable stiffness joint design using translational variable radius pulleys
(Pergamon-Elsevier Science Ltd, 2018) Yiğit, Cihat Bora; Bayraktar, Ertuğrul; Boyraz, Pınar
Robot joints are expected to be safe, compliant, compact, simple and low-cost. Gravity compensation, zero backlash, energy efficiency and stiffness adjustability are some desired features in the robotic joints. The variable radius pulleys (VRPs) provide a simple, compact and low-cost solution to the stiffness adjustment problem. VRP mechanisms maintain a preconfigured nonlinear force-elongation curve utilizing off-the-shelf torsional spring and pulley profile. In this paper, three synthesis algorithms are presented for VRP mechanisms to obtain desired force-elongation curve. In addition, a feasibility condition is proposed to determine the torsional spring coefficient. Using the synthesis methods and the feasibility condition, a variable stiffness mechanism is designed and manufactured which uses two VRPs in an antagonistic cable driven structure. Afterwards, the outputs of three synthesis methods are compared to force-elongation characteristics in the tensile testing experiment. A custom testbed is manufactured to measure the pulley rotation, cable elongation and tensile force at the same time. Using the experiment as the baseline, the best algorithm achieved to reproduce the desired curve with a root-mean-square (RMS) error of 13.3%. Furthermore, VRP-VSJ is implemented with a linear controller to reveal the performance of the mechanism in terms of position accuracy and stiffness adjustability. (C) 2018 Elsevier Ltd. All rights reserved.
Isolated High Step-Up DC-DC Converter With Low Voltage Stress
(Ieee-Inst Electrical Electronics Engineers Inc, 2014) Evran, Fatih; Aydemir, Mehmet Timur
Fuel cell stacks and photovoltaic panels generate rather low dc voltages and these voltages need to be boosted before converted to ac voltage. Therefore, high step-up ratio dc-dc converters are preferred in renewable energy systems. A new Z-source-based topology that can boost the input voltage to desired levels with low duty ratios is proposed in this paper. The topology utilizes coupled inductor. The leakage inductance energy can efficiently be discharged. Since the device stresses are low in this topology, low-voltage MOSFETs with small RDS (on) values can be selected to reduce the conduction loss. These features improve the converter efficiency. Also, the converter has a galvanic isolation between source and load. The operating principles and steady-state analysis of continuous and discontinuous conduction modes are discussed in detail. Finally, experimental results are given for a prototype converter that converts 25 V dc to 400 V dc at various power levels with over 90% efficiency to verify the effectiveness of the theoretical analysis.
Correlation between barrier height and ideality factor in identically prepared diodes of Al/Bi4Ti3O12/p-Si (MFS) structure with barrier inhomogeneity
(Elsevier Science Sa, 2017) Çetinkaya, H.G.; Yıldırım, Mert; Durmuş, Perihan; Altındal, Şemsettin
This study aims to investigate electrical characteristics of identically prepared metal-ferroelectric-semiconductor (MFS) structures. Therefore a total number of 58 diodes were fabricated in the form of Al/Bi4Ti3O12/P-Si structure and then current-voltage (I-V) and admittance-voltage (C-V and G/omega-V) measurements were performed at room temperature. It was found that zero bias barrier height (Phi(Bo)) and ideality factor (n) show diode-to-diode variance. The value of n varied from 2.7 to 5.3 and such high values were attributed to the barrier height (BH) inhomogeneity, interfacial layer and surface states (N-ss). Similar behavior was observed for series resistance (R-s) values which were obtained by using Nicollian-Brews method. Other electrical parameters such as doping concentration of acceptor atoms (N-A), Fermi energy (E-F), and BH (Phi(B)) were extracted from reverse bias C-2-V characteristics. The experimental values of BH obtained from the forward bias I-V and reverse bias C-2-V characteristics varied from 0.69 to 0.84 eV and 0.75-0.93 eV and statistical analysis revealed mean BH values as 0.716 eV and 0.818 eV, respectively. We believe the variations in the electrical parameters are due to inhomogeneous interfacial layer and BH, non-uniformity of the interfacial traps or dislocations, and grain boundaries. (C) 2017 Elsevier B.V. All rights reserved.
ACTIVE POWER LOSS MINIMIZATION IN ELECTRIC POWER SYSTEMS THROUGH CHAOTIC ARTIFICIAL BEE COLONY ALGORITHM
(Univ Osijek, Tech Fac, 2016) Kuru, Leyla; Öztürk, Ali; Kuru, Ersen; Çobanlı, Serkan
Reactive power optimization (RPO) is a major field of study to ensure power systems for operating in a secure and economical manner. RPO can be used for decreasing of active power losses, voltage control, and for the optimization of the power coefficients in power systems. The non-linear power loss function is used as an object function that will be minimized. In this study Chaotic Artificial Bee Colony (CABC) algorithm is used to minimize the active power loss of power systems. Chaotic maps such as logistic map and Henon map are used against the random number generator. CABC is applied on the IEEE6-bus and IEEE 30-bus test systems and the results are shown. Accordingly, the results have been evaluated and observed that the stability critical values found by CABC can be used to produce good potential solutions. Simulation results are promising and show the effectiveness of the applied approach.
Bitkisel Bir Hidrolik Akışkan Üretimi ve Performansının Hidrolik Yağ ile Karşılaştırılması
(2019) Samtaş, Gürcan; Korucu, Salih
Günümüzdeki modern dünyada hidrolik; gün geçtikçe birçok alanda insanların yaşantısında çok önemli pay sahibiolmaktadır. Hidrolikte enerjiyi sağlayan temel unsur akışkandır ve akışkana yön veren ekipmanlar valfler olarakadlandırılır. Valflerin genel olarak doğrudan el ile ya da elektriksel sinyal vasıtasıyla kumanda edilmesi, hareketlihidrolik sistemin karakteristik bir özeliğidir. Bir hidrolik sistemde en önemli tek malzeme kendi kendine çalışanhidrolik akışkandır. Hidrolik yağın karakteristik özellikleri, ekipmanların performans ve ömürleri üzerinde büyükbir etkiye sahiptir. Dolayısıyla yüksek kalitede temiz bir akışkan kullanarak etkili bir hidrolik sistemoluşturulabilir. Ayrıca hidrolik sistemlerde bulunan sıvı akışkan, iş elemanı olarak silindirler içerisinde ne kadarlıkbir güç üreteceğini de belirler. Diğer taraftan bir hidrolik akışkan; gücün iletimi, hareket elemanlarının yağlanması,eş parçalar arasında conta görevi ve sistemde ısı dağılımı gibi amaçlar için de kullanılır. Bu çalışmada, doğadarahatça bulunabilen bitki ve bitki tohumları kullanılarak üretilen hidrolik akışkanın, viskozite indeksi 22 olannormal hidrolik yağ ile karşılaştırılması sunulmuştur. Karşılaştırmalar farklı elektro-hidrolik devrelerle yapılmışve yüke karşı yürütülen deneylerle hidrolik devre elemanlarının sıcaklıkları incelenmiştir.
Bitkisel Esaslı Bir Hidrolik Akışkanın Geliştirilmesi
(2017) Samtaş, Gürcan
Günümüzdeki modern dünyada hidrolik; gün geçtikçe birçok alanda insanların yaşantısında çok önemli pay sahibi olmaktadır. Hidrolikte enerjiyi sağlayan temel unsur akışkandır ve akışkana yön veren ekipmanlar valfler olarak adlandırılır. Valflerin genel olarak doğrudan el ile ya da elektriksel sinyal vasıtasıyla kumanda edilmesi, hareketli hidrolik sistemin karakteristik bir özeliğidir. Bir hidrolik sistemde en önemli tek malzeme kendi kendine çalışan hidrolik akışkandır. Hidrolik yağın karakteristik özellikleri, ekipmanların performans ve ömürleri üzerinde büyük bir etkiye sahiptir. Dolayısıyla yüksek kalitede temiz bir akışkan kullanarak etkili bir hidrolik sistem oluşturulabilir. Ayrıca hidrolik sistemlerde bulunan sıvı akışkan, iş elemanı olarak silindirler içerisinde ne kadarlık bir güç üreteceğini de belirler. Diğer taraftan bir hidrolik akışkan; gücün iletimi, hareket elemanlarının yağlanması, eş parçalar arasında conta görevi ve sistemde ısı dağılımı gibi amaçlar için de kullanılır. Hidrolik bir sistemi harekete geçiren de odur. Bu çalışmada, doğada rahatça bulunabilen bitki ve bitki tohumları kullanılarak hidrolik yağ yerine geçebilecek hidrolik akışkan üretilmiştir. Üretilen akışkan viskozite değerleri ölçülmüş, ideal bitki karışım oranları belirlenmiştir. Akışkanın viskozite değerleri karşılaştırılmıştır

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