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Propulsion systems of LNG ships
No full textOvaj diplomski rad analizira i uspoređuje energetsku učinkovitost pogonskih sustava na LNG brodovima. Analizirani sustavi pogona su: parnotrubinsko postrojenje, postrojenje s dvotaktnim sporookretnim motorima i sustavom za ponovno ukapljivanje plina, elektropropulzija s Wärtsilä generatorima na dvojno gorivo, elektropropulzija s MAN generatorima na dvojno gorivo, elektropropulzija Wärtsilä generatorima na dvojno gorivo i azipod propulzijom, postrojenje s dvotaktnim ME-GI motorima na dvojno gorivo – visokotlačni plin i postrojenje s dvotaktnim X-DF motorima na dvojno gorivo – niskotlačni plin. Za svaki od ovih pogona izračunata je termička energetska učinkovitost te proračunski indeks energetske učinkovitosti (EEDI – Energy Efficiency Design Index), odnosno indeks energetske učinkovitosti postojećih brodova (EEXI – Energy Efficiency Existing ships Index). Proučen je i novi ME-GA motor tvrtke MAN i dane su osnovne značajke motora na amonijak koji bi mogao biti budući odabir pogona za LNG brodove.This master's thesis analyzes and compares the energy efficiency of propulsion systems on LNG ships. The analyzed propulsion systems include: steam turbine plant, two-stroke slow-speed engine plant with gas reliquefaction system, electric propulsion with Wärtsilä dual-fuel generators, electric propulsion with MAN dual-fuel generators, electric propulsion with Wärtsilä dual-fuel generators and Azipod propulsion, plant with two-stroke dual-fuel ME-GI engines with high pressure gas injection and plant with two-stroke dual-fuel X-DF engines with low-pressure gas admission. Thermal energy efficiency, along with energy efficiency indexes – EEDI and EEXI has been calculated for each of these propulsion systems. Additionally, the thesis examines the new ME-GA engine by MAN and provides basic features of an ammonia-powered engine, which could be a potential future propulsion choice for LNG ships
Propulsion systems of LNG ships
No full textOvaj diplomski rad analizira i uspoređuje energetsku učinkovitost pogonskih sustava na LNG brodovima. Analizirani sustavi pogona su: parnotrubinsko postrojenje, postrojenje s dvotaktnim sporookretnim motorima i sustavom za ponovno ukapljivanje plina, elektropropulzija s Wärtsilä generatorima na dvojno gorivo, elektropropulzija s MAN generatorima na dvojno gorivo, elektropropulzija Wärtsilä generatorima na dvojno gorivo i azipod propulzijom, postrojenje s dvotaktnim ME-GI motorima na dvojno gorivo – visokotlačni plin i postrojenje s dvotaktnim X-DF motorima na dvojno gorivo – niskotlačni plin. Za svaki od ovih pogona izračunata je termička energetska učinkovitost te proračunski indeks energetske učinkovitosti (EEDI – Energy Efficiency Design Index), odnosno indeks energetske učinkovitosti postojećih brodova (EEXI – Energy Efficiency Existing ships Index). Proučen je i novi ME-GA motor tvrtke MAN i dane su osnovne značajke motora na amonijak koji bi mogao biti budući odabir pogona za LNG brodove.This master's thesis analyzes and compares the energy efficiency of propulsion systems on LNG ships. The analyzed propulsion systems include: steam turbine plant, two-stroke slow-speed engine plant with gas reliquefaction system, electric propulsion with Wärtsilä dual-fuel generators, electric propulsion with MAN dual-fuel generators, electric propulsion with Wärtsilä dual-fuel generators and Azipod propulsion, plant with two-stroke dual-fuel ME-GI engines with high pressure gas injection and plant with two-stroke dual-fuel X-DF engines with low-pressure gas admission. Thermal energy efficiency, along with energy efficiency indexes – EEDI and EEXI has been calculated for each of these propulsion systems. Additionally, the thesis examines the new ME-GA engine by MAN and provides basic features of an ammonia-powered engine, which could be a potential future propulsion choice for LNG ships
Propulsion systems of LNG ships
No full textOvaj diplomski rad analizira i uspoređuje energetsku učinkovitost pogonskih sustava na LNG brodovima. Analizirani sustavi pogona su: parnotrubinsko postrojenje, postrojenje s dvotaktnim sporookretnim motorima i sustavom za ponovno ukapljivanje plina, elektropropulzija s Wärtsilä generatorima na dvojno gorivo, elektropropulzija s MAN generatorima na dvojno gorivo, elektropropulzija Wärtsilä generatorima na dvojno gorivo i azipod propulzijom, postrojenje s dvotaktnim ME-GI motorima na dvojno gorivo – visokotlačni plin i postrojenje s dvotaktnim X-DF motorima na dvojno gorivo – niskotlačni plin. Za svaki od ovih pogona izračunata je termička energetska učinkovitost te proračunski indeks energetske učinkovitosti (EEDI – Energy Efficiency Design Index), odnosno indeks energetske učinkovitosti postojećih brodova (EEXI – Energy Efficiency Existing ships Index). Proučen je i novi ME-GA motor tvrtke MAN i dane su osnovne značajke motora na amonijak koji bi mogao biti budući odabir pogona za LNG brodove.This master's thesis analyzes and compares the energy efficiency of propulsion systems on LNG ships. The analyzed propulsion systems include: steam turbine plant, two-stroke slow-speed engine plant with gas reliquefaction system, electric propulsion with Wärtsilä dual-fuel generators, electric propulsion with MAN dual-fuel generators, electric propulsion with Wärtsilä dual-fuel generators and Azipod propulsion, plant with two-stroke dual-fuel ME-GI engines with high pressure gas injection and plant with two-stroke dual-fuel X-DF engines with low-pressure gas admission. Thermal energy efficiency, along with energy efficiency indexes – EEDI and EEXI has been calculated for each of these propulsion systems. Additionally, the thesis examines the new ME-GA engine by MAN and provides basic features of an ammonia-powered engine, which could be a potential future propulsion choice for LNG ships
Breakdown Diagnostics of Marine Steam
No full textBrodske parne turbine su toplinski strojevi u kojima se toplinska energija vodene pare pretvara u mehaničku energiju koja se prenosi na brodski vijak. Uvjeti za učinkovit pogon brodskog parnoturbinskog postrojenja su sigurnost, ekonomičnost i rad sa što manje kvarova i zastoja. Tijekom plovidbe potrebno je nadgledati sustave te dođe li do kvara otkloniti uzrok. U ovom radu navedeni su kvarovi i njihovi mogući uzroci te su opisani postupci otklanjanja kvarova u sustavu ulja, sustavu kondenzata, upravljačkom sustavu te na samoj turbini. Za svaki kvar i zastoj postoje ispravna rješenja navedena u priručniku.Marine steam turbines are thermal machines in which thermal energy of water steam is converted into mechanical energy which is transferred on propeller. Conditions for effective operation of marine steam turbine plant are safety, economy and work with as little failures and malfunctions as possible. During voyage it is necessary to control the plant and if any failure occurs remove the cause. Failures, their possible causes and removal procedures in oil, condensate and control systems and on the turbine itself are listed in this paper. There are correct solutions for each and every failure and malfunction and they are specified in the manuals
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
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
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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