5 results
Search Results
Now showing 1 - 5 of 5
Conference Object PARAMETER OPTIMIZATION OF A PBI MEMBRANE-BASED HIGH TEMPERATURE-ELECTROCHEMICAL HYDROGEN COMPRESSOR FED WITH H2 AND CO MIXTURE(International Association for Hydrogen Energy, IAHE, 2022) Kuzu,C.; Ozgur Colpan,C.; Durmuş,G.N.B.; Devrim,Y.In today's world, the increase in the amount of energy needed with the increase in the human population and the depletion of fossil fuels has pushed researchers to search for alternative fuels. Hydrogen is expected to take an important share among the alternative fuels in the future. However, it has some challenges in terms of its storage and pressurization. In this study, the effect of back diffusion on the performance of a PBI membrane-based electrochemical hydrogen compressor operating at 160 °C. Pressure values are calculated and validated with experimental results; and the change of flux, voltage and cell efficiency with time are presented. © 2022 Proceedings of WHEC 2022 - 23rd World Hydrogen Energy Conference: Bridging Continents by H2. All rights reserved.Article Citation - WoS: 3Citation - Scopus: 3Modeling Chlorine Decay in Drinking Water Distribution Network: Case Study of Antalya, Turkey(Parlar Scientific Publications (p S P), 2005) Tiryakioglu, O; Muhammetoglu, A; Muhammetoglu, H; Soyupak, SThe well known hydraulic and water quality network simulation model, EPANET, is applied to the drinking water distribution network of Baris District in Antalya City, Turkey. Nine measurement and sampling stations were chosen to represent the study area. The water pressure at the pumping station was recorded during the field measurements while two different sets of water samples were analyzed in the field for chlorine residual at all the stations. Additional water samples were collected at some stations and analyzed for many physical, chemical and biological water quality parameters. Moreover, the bottle chlorine bulk decay coefficient was determined in the lab as 4.3434 day(-1). The two different field measurement sets are used to calibrate and verify the model. The calibration process resulted in a wall reaction coefficient equal to 0.025 m day(-1). In addition to predicting the chlorine residual levels along the network, the model also predicts many hydraulic characteristics such as pressure, velocity and flow rates in the network.Article Citation - Scopus: 1Adaptive Neuro-Fuzzy Inference Technique for Estimation of Light Penetration in Reservoirs(Springer Japan Kk, 2007) Soyupak, Selcuk; Karaer, Feza; Senturk, Engin; Hekim, HuseyinAn adaptive neuro-fuzzy inference technique has been adopted to estimate light levels in a reservoir. The data were collected randomly from Doganci Dam Reservoir over a number of years. The input data set is a matrix with vectors of time, depth, sampling location, and incident solar radiation. The output data set is a vector representing light measured at various depths. Randomization and logarithmic transformations have been applied as preprocessing. One-half of the data have been utilized for training; testing and validation steps utilized one-fourth each. An adaptive neuro-fuzzy inference system (ANFIS) has been built as a prediction model for light penetration. Very high correlation values between predictions and real values on light measurements with relatively low root mean square error values have been obtained for training, test, and validation data sets. Elimination of the overtraining problem was ensured by satisfying close root mean square error values for all sets.Article Citation - WoS: 17Citation - Scopus: 23Inductance Measurement Methods for Surface-Mount Permanent Magnet Machines(Ieee-inst Electrical Electronics Engineers inc, 2023) Ertan, H. Bulent; Sahin, IlkerAnalytical performance estimation of a permanent magnet (PM) motor requires an accurate equivalent circuit model. In a lumped electrical model of a PM motor, resistance and inductances appear as passive elements, which are used to represent the phase winding resistance, inductance, core loss, etc. There is currently no available standard for parameter measurement of PM motors. In the literature, there are many studies on inductance measurement. However, they are applied to different types of motors. The purpose of this study is to evaluate those different inductance measurement methods, on the same motors, to identify whether they lead to the same result. Also, it was aimed to find out the difficulties involved in the measurement process. This study concentrates on determining the d -axis and q -axis inductances of two different surface-mount PM motors at standstill and under running conditions. The standstill measurement methods evaluated include the "current decay " method and the "dc inductance bridge " method as well as more common methods. The dependence of the inductances on the current magnitude, frequency, and excitation signal waveform is investigated. Measurements with PWM and sinusoidal ac voltage excitation are found to give similar results. The tests indicated that the "current decay " method is prone to measurement errors especially when the phase resistance is low. It is discovered that inductance measurements from standstill tests are independent of frequency for all practical purposes. Next, the same inductances are measured, while the test motors are running. The methods considered include; inductance measurement from no-load test, zero power factor (PF) load test, and unity PF load test; while the machine is in generating mode. Furthermore, a new inductance measurement method is introduced where the measurement is made while the test motor is driven with a vector-controlled drive. Finally, inductance measurement results from different standstill tests and running tests are compared and evaluated.Article Citation - WoS: 22Citation - Scopus: 26Insights From Pupil Size To Mental Workload of Surgical Residents: Feasibility of an Educational Computer-Based Surgical Simulation Environment (ece) Considering the Hand Condition(Sage Publications inc, 2018) Dalveren, Gonca Gokce Menekse; Cagiltay, Nergiz Ercil; Ozcelik, Erol; Maras, HakanThe advantage of simulation environments is that they present various insights into real situations, where experimental research opportunities are very limited-for example, in endoscopic surgery. These operations require simultaneous use of both hands. For this reason, surgical residents need to develop several motor skills, such as eye-hand coordination and left-right hand coordination. While performing these tasks, the hand condition (dominant, nondominant, both hands) creates different degrees of mental workload, which can be assessed through mental physiological measures-namely, pupil size. Studies show that pupil size grows in direct proportion to mental workload. However, in the literature, there are very limited studies exploring this workload through the pupil sizes of the surgical residents under different hand conditions. Therefore, in this study, we present a computer-based simulation of a surgical task using eye-tracking technology to better understand the influence of the hand condition on the performance of skill-based surgical tasks in a computer-based simulated environment. The results show that under the both-hand condition, the pupil size of the surgical residents is larger than the one under the dominant and nondominant hand conditions. This indicates that when the computer-simulated surgical task is performed with both hands, it is considered more difficult than in the dominant and nondominant hand conditions. In conclusion, this study shows that pupil size measurements are sufficiently feasible to estimate the mental workload of the participants while performing surgical tasks. The results of this study can be used as a guide by instructional system designers of skill-based training programs.
