236 research outputs found
Energetska varnost v času krize: študiji primera Bolgarije in Srbije
No full textThis thesis aims to assess the EU’s external energy policy and to what degree it has been embraced by small states during the energy crisis by posing the question, “How does European Union membership influence the external energy policy decisions of small states within the foreign policy dimension during energy security crises?”. To answer this, the research is taking Bulgaria and Serbia as case studies due to their similar population sizes, GDP, and energy consumptions. This research conceptualizes energy security and energy diplomacy to understand how diplomacy and energy dependencies are interrelated and how this relationship can be utilised as a tool in international relations. Through supporting the qualitative work on foreign policy analysis with the quantitative analysis of the energy industry structures and energy dependencies of Serbia and Bulgaria in a comparative manner, this research is conducting mixed research on the issue. The comparison of Bulgaria and Serbia enables the author to analyse and understand the role of EU membership
Finite Difference Analysis of a Resistive Sintering System Container
No full textResistive sintering is a new method which enables the production of different material types by using mechanical load and electric current. For the required process performance, it is necessary to set the parameters such as current, voltage, dissipated power, electric energy, and production time correctly. The container is an important component of the resistive sintering system. Container electrical resistance is a value that is difficult to calculate in terms of the geometry of the build and to measure due to the smallness of the value. In this study, assuming that the container temperature is constant, the Laplace equation of the electric potential is solved in the cylindrical coordinates considering the axial symmetry by the finite difference method and then the electrical current and resistance of the sintering container was calculated by post-processing of the solved electric potential using Ohm's law in vector form. The volumetric power density is used to calculate the dissipated power in the container and the container current is calculated on the stiff area. It is seen that the current density is almost doubled at the stiff-container edges and the power density at these points reaches its maximum. At points distant from the stiffs, the electrical potential is almost constant and the potential difference is negligible. The main source of heating is shown to be the resistance of the stiffs. The resistance of the structure is found to be about 70 mu Omega. This method given here can be used in more sophisticated models to size an ECAS system
A process control method for the electric current-activated/assisted sintering system based on the container-consumed power and temperature estimation
No full textIn this paper, the current, voltage and temperature of the container of an electric current-activated/assisted sintering (ECAS) system are measured and recorded with respect to time during the sintering process. By post-processing of the recorded data, the power and thermal energy of the system container are calculated. Interpretation of the measured and post-processed data has provided a criterion: It has been found that the dissipated electrical power in quasi-steady state is almost equal to the power conducted from the container to the copper bars throughout the stiffs and the convection and radiation powers are negligible compared to the conducted power. Therefore, the container-stored thermal energy or the container surface temperature can be estimated from the dissipated electrical power with the values of the container heat capacitance and the stiff thermal resistances without the need for a temperature measurement equipment. If the thermal energy or the temperature required to make the samples has a known/required minimum value and if this amount of the thermal energy is provided to the sample, the sample production process can be stopped. In this study, for an actual implemented design, we suggest that ECAS current and voltages should be continuously measured in real time and the process is automatically terminated when the calculated steady-state container temperature becomes equal to the required container temperature. Therefore, a standard procedure for material production in ECAS system is provided to automate sample production and the performance of the produced samples is guaranteed
Investigation of Factors That May Affect the Commitment of Healthcare Professionals to Their Works During the COVID-19 Pandemic Period
No full textThe environment of uncertainty created by the COVID-19 pandemic period has caused difficulties especially for healthcare professionals in their work activities. The purpose of this research is to find out which variables might affect the commitment of healthcare professionals to their works during this COVID-19 period. Based on the data announced by the Ministry of Health during the pandemic in the first quarter of 2021, it was decided to conduct a research on doctors, nurses, caregivers, and medical secretaries working in hospitals in the cities of the Eastern Black Sea Region of Turkey which generally show high risk. In the developed research model, satisfactory conditions (SC), emotional commitment to change (ECC), and psychological ownership (PO) as variables that may directly or indirectly affect the commitment of healthcare professionals to their works (CW) were used. The Smart PLS program was used in the analysis of the research model and hypothesis. It was seen that the ECC of healthcare professionals has a positive and significant (.694; p .086). Looking at the indirect (intermediary) effects obtained as a result of the research, it was seen that all of the hypotheses consist of positive coefficients. This situation reveals that the mediating variables have complementary effects on the obtained results. © The Author(s) 2022.WOS:00078698580000
Examination of a Memristor-Based Low-Pass Filter Topology
No full textIn this work, a memristor based low-pass filter topology in which a memristor is placed as the input element and a capacitor is placed as the negative feedback element to an inverting op-amp is examined. The memristor provides adjustable gain characteristic to the filter. Analytical solution of the filter is obtained its output voltage, the memristor current, and the capacitor voltage are found as a function of time. To obtain the filter small-signal model and examine its frequency behavior, Maclaurin series expansion for the output voltage is performed. Time and frequency domain simulations of the filter are done using both small signal and dynamic models of the filter. The frequency domain gain and THD characteristic of the filter are also obtained using both of the models. Simulation results of both of the models are compared. It is shown that the small signal model is able to predict the filter behavior accurately for small signals. It has been also found that, for this topology at low frequencies, the input signal magnitude should be limited for a low distortion
Bibliometric profile of articles published in the field of gastronomy (2013-2017)
No full textBu araştırmanın amacı Türkiye’de gastronomi alanında yazılmış makalelerin
bibliyometrik olarak incelenmesidir. Araştırmanın evrenini, Türkiye’de 2013-2017
yılları arasında gastronomi alanında yayınlanan makaleler oluşturmaktadır. 2013-
2017 yılları arasında 14 farklı dergide gastronomi alanında 202 makale tespit
edilmiş olup, bu makaleler toplam 443 yazar tarafından kaleme alınmıştır.
Çalışmada nitel araştırma yöntemi tercih edilmiş olup, verilerin analizinde betimsel
analiz yöntemi kullanılmıştır. Makaleler yayınlanan dergi, yıl, dil, anahtar kelime,
yazar sayısı, tema, araştırma metotları ve referans kaynakları gibi değişkenler ele
alınarak incelenmiştir. Araştırma sonuçlarına göre, makalelerin en çok Turizm ve
Gastronomi Araştırmaları dergisinde yayınlandığı, 2017 yılında gastronomi temalı
makalelerin sayıca fazla olduğu, makalelerin %46,5 oran ile en çok iki yazar
tarafından ortak yayınlandığı, en çok makale yayınlayan üniversitenin Gazi
Üniversitesi olduğu, makalelerin en çok “Gastronomi ve Yiyecek İçecek
Endüstrisi” temasında yazıldığı tespit edilmiştirThe aim of this research is to examine the bibliometric of articles written in Turkey
in the field of gastronomy. The universe of the study consists of articles published
in the field of gastronomy in Turkey between the years 2013-2017. 202 articles on gastronomy in 14 different journals between 2013 and 2017 have been identified
and these articles have been written by 443 authors. Qualitative research method
was preferred in this study and descriptive analysis method was used in data
analysis. Articles such as journal, year, language, keyword, author number, theme,
research methods and reference sources were examined. According to the results of
the research, the most of the articles were published in the Journal of Tourism and
Gastronomy Researches, in 2017 there were a large number of gastronomy-themed
articles. It has been found that it is written in the “Gastronomy and Food Beverage
Industry” theme
Small signal analysis of memristor-based low-pass and high-pass filters using the perturbation theory
No full textIn this study, perturbation theory has been used for the first time in literature to do small-signal analysis and solution of the memristor-based low-pass and high-pass filters are given using perturbation theory. The time and frequency domain memristor-based filter behaviors are obtained analytically. It has been found that the second harmonic does exist and is dominant and its behavior as a function of frequency is inspected in these filters. The gain responses and the total harmonic distortions of the filters are also given. Results obtained from the perturbation theory are in good agreement with that of numerical simulations and this confirms the accuracy and the performance of the method
MEMRISTOR BASED SALLEN-KEY FILTERS
No full textIn 1971, memristor is claimed as a missing circuit element and almost 40 years later than its prediction a memristive system behaving as a memristor has been found in 2008. Memristor is accepted by many as the new and the fourth fundamental circuit element. Analog applications of memristor have emerged as a new research area in recent years. An analog filter with memristor can have automatically adjustable gain, quality factor and bandwidth characteristics etc. thanks to its variable memristance. In this paper, two different types of second-order Sallen-Key filters, which are the low-pass and the high-pass Sallen Key filters, are analyzed using simulations. The linear drift model of TiO2 memristor is used in all analysis and simulations. It has been found that the memristor in the filters can go into saturation at very low frequencies and both of the filters operate well at higher frequencies. A criterion is suggested to prevent memristor from going into saturation and to prevent distortion at low frequencies. Using the criteria and choosing a memristor with more appropriate parameters, the simulations are repeated for the low-pass filter and it is shown that the low-pass filter operates better with the new parameters chosen. The analysis and the criteria given in this paper can be used to design memristor-based Sallen-Key filters and adaptable to other memristor-based filters as well
A new memristor-based low-pass filter topology and its small-signal solution using MacLaurin series
No full textIn this work, a new memristor-based low-pass filter topology is suggested. Memristor-based filters are nonlinear circuits and many of them cannot be solved analytically. To find an approximate analytical solution of the filter equations, MacLaurin series is used for the first time. Time and frequency domain behavior of the filter are obtained. Also, the frequency domain gain and total harmonic distortion characteristics of the filter are given. Results obtained by the small signal model have been compared with the dynamic model results. It is shown that the small signal model is able to predict the filter behavior very well
Modeling and analysis of schottky diode bridge and JFET based liénard oscillator circuit
No full textLi & eacute;nard Oscillator circuit has numerous variations. Nowadays, due to the developments of semiconductor technology, such an oscillator can be made using various semiconductor circuit elements. In this study, it has been shown that a Li & eacute;nard Oscillator can also be made using a Schottky diode bridge and a JFET based nonlinear resistor. First, the new Li & eacute;nard Oscillator topology is given, then, the dynamic model of the circuit is derived, and the simulations of the circuit are made. The currents, voltages and limit cycle of the Li & eacute;nard Oscillator circuit are obtained with simulations using LTspice circuit analysis program. The simulations have confirmed that the circuit operates as a Li & eacute;nard Oscillator
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