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Thermodynamic principles of jet engines
No full textCilj ovog rada je prikazati termodinamički princip rada mlaznog motora. Na početku rada napravljen je kratak osvrt na razvoja mlaznih motora kroz povijest. Prikazana je i osnovna podjela mlaznih motora te prednosti i nedostaci svake vrste. Nadalje, opisani su osnovni dijelovi mlaznog motora i njihova funkcija. U radu je opisano i prikazano jednadžbama kako nastaje potisak te je prikazan izvod do jednostavnog izraza za računanje potiska. Zatim je opisana termodinamika mlaznih motora. Prikazani su idealni i stvarni Braytonov ciklus te su navedeni gubici stvarnog ciklusa. Osim općenitog prikaza Braytonovog ciklusa, na kraju rada je prikazana termodinamička analiza turbomlaznog motora.The purpose of this paper is to present the thermodynamic principle of a jet engine. A short history review of the jet engines is written at the beginning of the paper. The main classification of jet engines and the advantages and disadvantages of each type are also presented. Furthermore, the main parts of a jet engine and their function are described. Through equations the paper describes and presents how the thrust occurs and it shows the process to reaching a simple mathematical form for calculating thrust. Afterwards the thermodynamics of jet engines are described. The ideal and the real Brayton cycle are shown and the real cycle losses are given. In addition to the general review of the Brayton cycle, the thermodynamic analysis of the turbojet engine is presented at the end of the paper
Thermodynamic principles of jet engines
No full textCilj ovog rada je prikazati termodinamički princip rada mlaznog motora. Na početku rada napravljen je kratak osvrt na razvoja mlaznih motora kroz povijest. Prikazana je i osnovna podjela mlaznih motora te prednosti i nedostaci svake vrste. Nadalje, opisani su osnovni dijelovi mlaznog motora i njihova funkcija. U radu je opisano i prikazano jednadžbama kako nastaje potisak te je prikazan izvod do jednostavnog izraza za računanje potiska. Zatim je opisana termodinamika mlaznih motora. Prikazani su idealni i stvarni Braytonov ciklus te su navedeni gubici stvarnog ciklusa. Osim općenitog prikaza Braytonovog ciklusa, na kraju rada je prikazana termodinamička analiza turbomlaznog motora.The purpose of this paper is to present the thermodynamic principle of a jet engine. A short history review of the jet engines is written at the beginning of the paper. The main classification of jet engines and the advantages and disadvantages of each type are also presented. Furthermore, the main parts of a jet engine and their function are described. Through equations the paper describes and presents how the thrust occurs and it shows the process to reaching a simple mathematical form for calculating thrust. Afterwards the thermodynamics of jet engines are described. The ideal and the real Brayton cycle are shown and the real cycle losses are given. In addition to the general review of the Brayton cycle, the thermodynamic analysis of the turbojet engine is presented at the end of the paper
Electric vehicle range vs. road condition
No full textDomet je jedna od najvažnijih karakteristika električnih vozila, a odnosi se na broj kilometara koje električno vozilo može prijeći s potpuno napunjenom baterijom. Postoji veliki broj parametara koji imaju utjecaj na domet električnog vozila, a neki od njih su baterija, stil vožnje vozača i okolišni uvjeti. U ovome radu istraživana je ovisnost dometa električnih vozila o uvjetima vožnje. U tu svrhu uzete su realne vrijednosti potrošnje električne energije dobivene mjerenjem pri četiri različite brzine vožnje. Pomoću podataka o potrošnji energije i iskoristivom kapacitetu baterije izračunat je domet električnih vozila pri sve četiri brzine vožnje, te je napravljena usporedba između dometa koji propisuju proizvođači električnih vozila i dometa u realnim uvjetima vožnje. Brzina vožnje ima utjecaj na potrošnju električne energije i na domet električnih vozila.Range is one of the most important characteristics of electric vehicles and it is referred to as the number of kilometers an electric vehicle can travel with a fully charged battery. There are a large number of parameters that have an impact on the range of an electric vehicle, some of them are the battery, the driver's driving style and environmental conditions. In this paper the focus was on the dependence of the range of electric vehicles on driving conditions. For this purpose, real values of electric energy consumption obtained by measurement at four different driving speeds were taken. Using data on energy consumption and usable battery capacity, the range of electric vehicles at all four driving speeds was calculated and a comparison was made between the range prescribed by electric vehicle manufacturers and the range in real driving conditions. Driving speed has an impact on the electric energy consumption and on the range of electric vehicles
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Electric vehicle range vs. road condition
No full textDomet je jedna od najvažnijih karakteristika električnih vozila, a odnosi se na broj kilometara koje električno vozilo može prijeći s potpuno napunjenom baterijom. Postoji veliki broj parametara koji imaju utjecaj na domet električnog vozila, a neki od njih su baterija, stil vožnje vozača i okolišni uvjeti. U ovome radu istraživana je ovisnost dometa električnih vozila o uvjetima vožnje. U tu svrhu uzete su realne vrijednosti potrošnje električne energije dobivene mjerenjem pri četiri različite brzine vožnje. Pomoću podataka o potrošnji energije i iskoristivom kapacitetu baterije izračunat je domet električnih vozila pri sve četiri brzine vožnje, te je napravljena usporedba između dometa koji propisuju proizvođači električnih vozila i dometa u realnim uvjetima vožnje. Brzina vožnje ima utjecaj na potrošnju električne energije i na domet električnih vozila.Range is one of the most important characteristics of electric vehicles and it is referred to as the number of kilometers an electric vehicle can travel with a fully charged battery. There are a large number of parameters that have an impact on the range of an electric vehicle, some of them are the battery, the driver's driving style and environmental conditions. In this paper the focus was on the dependence of the range of electric vehicles on driving conditions. For this purpose, real values of electric energy consumption obtained by measurement at four different driving speeds were taken. Using data on energy consumption and usable battery capacity, the range of electric vehicles at all four driving speeds was calculated and a comparison was made between the range prescribed by electric vehicle manufacturers and the range in real driving conditions. Driving speed has an impact on the electric energy consumption and on the range of electric vehicles
Electric vehicle range vs. road condition
No full textDomet je jedna od najvažnijih karakteristika električnih vozila, a odnosi se na broj kilometara koje električno vozilo može prijeći s potpuno napunjenom baterijom. Postoji veliki broj parametara koji imaju utjecaj na domet električnog vozila, a neki od njih su baterija, stil vožnje vozača i okolišni uvjeti. U ovome radu istraživana je ovisnost dometa električnih vozila o uvjetima vožnje. U tu svrhu uzete su realne vrijednosti potrošnje električne energije dobivene mjerenjem pri četiri različite brzine vožnje. Pomoću podataka o potrošnji energije i iskoristivom kapacitetu baterije izračunat je domet električnih vozila pri sve četiri brzine vožnje, te je napravljena usporedba između dometa koji propisuju proizvođači električnih vozila i dometa u realnim uvjetima vožnje. Brzina vožnje ima utjecaj na potrošnju električne energije i na domet električnih vozila.Range is one of the most important characteristics of electric vehicles and it is referred to as the number of kilometers an electric vehicle can travel with a fully charged battery. There are a large number of parameters that have an impact on the range of an electric vehicle, some of them are the battery, the driver's driving style and environmental conditions. In this paper the focus was on the dependence of the range of electric vehicles on driving conditions. For this purpose, real values of electric energy consumption obtained by measurement at four different driving speeds were taken. Using data on energy consumption and usable battery capacity, the range of electric vehicles at all four driving speeds was calculated and a comparison was made between the range prescribed by electric vehicle manufacturers and the range in real driving conditions. Driving speed has an impact on the electric energy consumption and on the range of electric vehicles
Thermodynamic principles of jet engines
No full textCilj ovog rada je prikazati termodinamički princip rada mlaznog motora. Na početku rada napravljen je kratak osvrt na razvoja mlaznih motora kroz povijest. Prikazana je i osnovna podjela mlaznih motora te prednosti i nedostaci svake vrste. Nadalje, opisani su osnovni dijelovi mlaznog motora i njihova funkcija. U radu je opisano i prikazano jednadžbama kako nastaje potisak te je prikazan izvod do jednostavnog izraza za računanje potiska. Zatim je opisana termodinamika mlaznih motora. Prikazani su idealni i stvarni Braytonov ciklus te su navedeni gubici stvarnog ciklusa. Osim općenitog prikaza Braytonovog ciklusa, na kraju rada je prikazana termodinamička analiza turbomlaznog motora.The purpose of this paper is to present the thermodynamic principle of a jet engine. A short history review of the jet engines is written at the beginning of the paper. The main classification of jet engines and the advantages and disadvantages of each type are also presented. Furthermore, the main parts of a jet engine and their function are described. Through equations the paper describes and presents how the thrust occurs and it shows the process to reaching a simple mathematical form for calculating thrust. Afterwards the thermodynamics of jet engines are described. The ideal and the real Brayton cycle are shown and the real cycle losses are given. In addition to the general review of the Brayton cycle, the thermodynamic analysis of the turbojet engine is presented at the end of the paper
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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