Ship electric propulsion motors comparison

U radu su definirani i objašnjeni utjecajni čimbenici za evaluaciju brodskih porivnih elektromotora kao što su: stupanj korisnosti, duljina, promjer, težina, faktor snage, cijena, pouzdanost, tolerantnost na kvarove, obim i jednostavnost održavanja, kompatibilnost s pretvaračima frekvencije, otpornost na klimatske uvjete, koroziju, vibracije i udarce. Na toj osnovi su analizirane prednosti i nedostaci asinkronih i sinkronih motora u komercijalnoj primjeni. Od sinkronih motora uzeti su u obzir klasični sa četkicama, beskontaktni s uzbudnim namotima i najmoderniji s permanentnim magnetima. Motori su analizirani iz aspekta primjene u podtrupnim porivnicima, odnosno fiksne ugradnje u trup broda. Zaključeno je da su za ugradnju u podtrupne porivnike najbolji sinkroni motori s permanentnim magnetima, ali da kod manjih snaga, uglavnom zbog znatno niže cijene, može biti isplativa i primjena asinkronih kaveznih motora. Među elektromotorima za ugradnju u trup broda, su za vrlo velike snage trenutačno još uvijek najpovoljniji klasični sinkroni motori s uzbudnim namotima i četkicama, a za manje snage asinkroni kavezni motori u kombinaciji s reduktorom.This article aims at defining and explaining relevant factors important for the evaluation of electric propulsion motors such as efficiency, length, diameter, weight, power factor, price, reliability, fault tolerance, maintenance, compatibility with frequency converters, as well as weather, corrosion, vibration and shock resistance. On the basis of these facts, the advantages and disadvantages of the commercially used squirrel cage induction machines and synchronous machines are analyzed. Among the synchronous machines, standard motors with field coils - brushless and with slip rings - as well as the radial flux permanent magnet motors are taken into consideration. The motors are compared from both the point of podded drive and the shaft line propulsion. The conclusion is that for podded drives, permanent magnet synchronous motors are the best option, although the use of the squirrel cage induction machines, mainly because of their much lower prices, might be profitable for smaller units. In the case of direct shaft line electric propulsion with very high propulsion power and low turns, synchronous motors with field coils and slip rings are still the best choice, while for geared shaft line propulsion with lower propulsion power squirrel cage induction machines could be recommended

Termička stabilnost tankih slojeva TiO2 dobivenih kemijskim taloženjem iz pare. XPS i AES karakterizacija

Thermal stability of TiO2 thin polycrystalline films obtained by the very simple chemical vapour deposition method on the quartz, molybdenum and gold substrates have been examined by X-ray photoelectron and Auger spectroscopy (XPS and AES), respectively, before and after annealing in vacuum at temperatures from 298 K to 1200 K. In this temperature range we have found carbon, water, and O-H groups as the impurities at the surface of the films. The possible influence of both the annealing and the impurities on the film stoichiometry is discussed.Proučavana je termička stabilnost tankih, polikristaličnih slojeva TiO2 dobivenih jednostavnim kemijskim taloženjem iz pare na podloge iz kvarca, molibdena i zlata. Korištene su metode XPS i AES na uzorcima prije i poslije termičkog napuštanja u rasponu temperatura od 298 do 1200 K. Našli smo ugljik, vodu i O-H skupine kao nečistoće na površinama slojeva. Diskutirani su utjecaji termičkog napuštanja i nečistoća na stehiometriju slojeva

Raspršenje sinhrotronskog zračenja na malim kutovima priklona i raspršenja u tankim slojevima praha tio2 pripremljenim polaganjem iz para i rasprašivanjem

Nanosized TiO2, 1 μm thick, films on glass substrate were prepared using chemical vapour deposition (CVD) and spray method procedure. The average grain size , obtained by grazing-incidence small-angle scattering of synchrotron radiation (GISAXS) varied with the annealing temperature (500 to 900 °C in H2, O2 and N2) for the CVD prepared samples. For TiO2 films obtained by the spray method, increased with annealing temperature from 4.2 to 7.2 nm. Specific surface areas of both films were also determined and varied from 0.18·107 to 3.2·107 cm-1.Sloj TiO2 nanometarske veličine zrna, debljine 1 µm, polagao se je na staklene podloge metodama kemijskog polaganja iz para i rasprašivanjem. Prosječna veličina zrna, MRN, određena mjerenjem raspršenja sinhrotronskog zračenja na malim kutovima priklona i raspršenja, mijenjala se je s temperaturom toplinskog otpuštanja (500 do 900 °C u H2, O2 i N2) za uzorke pripremljene iz para. Za uzorke TiO2 pripremljene rasprašivanjem, MRN se je povećao s temperaturom otpuštanja od 4.2 do 7.2 nm. Spečificna površina obje vrste tankih slojeva se je također određivala i mijenjala od 0.18 · 10^7 do 3.2·10^7 cm-1

Integrated Command Bridge Navigation System

Tema ovog završnog rada je potpuno integrirani navigacijski sustav zapovjedničkog mosta. Moderni sustavi zapovjedničkog mosta imaju, osim opreme usko vezane za navigaciju i sigurnost plovidbe, također i uređaje kojima se nadgledaju i drugi odjeli na brodu, na primjer strojarnica. Modernizacijom svih brodskih procesa, prezasićenost informacijama postala je realnost svakog pomorca, što može dovesti do potencijalnog problema s kojim se pomorci susreću, oslanjajući se isključivo na modernu tehnologiju, a zanemarujući svoju procjenu i iskustvo. Završni rad donosi detaljan pregled modernog zapovjedničkog mosta, te će vam približiti ulogu modernih uređaja na sigurnost navigacije, primijenjenog na tankeru za prijevoz sirove nafte „Al Funtas“ izgrađenog 2014. godine.The topic of this is paper fully integrated command bridge navigation system. Modern bridge systems have, in addition to equipment closely related to navigation and safety of the vessel, also equipment to monitor other departments on board, such as the engine room. With modernization of all ship's processes, information overload has become a reality for every seafarer, which can lead to a potential problem that seafarers face relying solely on modern technology, neglecting their judgment and experience. This paper describes a detailed overview of the modern command bridge and brings you closer to the role of modern equipment on navigation safety, applied on VLCC „Al Funtas“, built in 2014

Integrated Command Bridge Navigation System

Tema ovog završnog rada je potpuno integrirani navigacijski sustav zapovjedničkog mosta. Moderni sustavi zapovjedničkog mosta imaju, osim opreme usko vezane za navigaciju i sigurnost plovidbe, također i uređaje kojima se nadgledaju i drugi odjeli na brodu, na primjer strojarnica. Modernizacijom svih brodskih procesa, prezasićenost informacijama postala je realnost svakog pomorca, što može dovesti do potencijalnog problema s kojim se pomorci susreću, oslanjajući se isključivo na modernu tehnologiju, a zanemarujući svoju procjenu i iskustvo. Završni rad donosi detaljan pregled modernog zapovjedničkog mosta, te će vam približiti ulogu modernih uređaja na sigurnost navigacije, primijenjenog na tankeru za prijevoz sirove nafte „Al Funtas“ izgrađenog 2014. godine.The topic of this is paper fully integrated command bridge navigation system. Modern bridge systems have, in addition to equipment closely related to navigation and safety of the vessel, also equipment to monitor other departments on board, such as the engine room. With modernization of all ship's processes, information overload has become a reality for every seafarer, which can lead to a potential problem that seafarers face relying solely on modern technology, neglecting their judgment and experience. This paper describes a detailed overview of the modern command bridge and brings you closer to the role of modern equipment on navigation safety, applied on VLCC „Al Funtas“, built in 2014

A new gastric juice peptide, BPC - an overview of stomach (stress) organoprotection hypothesis and BPC befitial effects

The possibility that the stomach affected by general stress pathology initiates a conteracting response has not been considered in the stress theory until recently. In this, the stomach as the most sensitive part of gastrointestinal tract, the largest neuroendocrine organ in the body, has been suggested to be a crutial point, from where a full stress response against all noxius stress pathology could be purposefully initiated, mediated and organized. The end result would be a strong protection of all organs invaded by "stress". Consistent with this assumption, this coping response is best explained in terms of "organoprotection" and endogenous organoprotectors (e.g. prostaglandins, somatostatin, dopamine) are proposed as mediators. Such an endogenous counteraction could even be afforded by their suitable application. According to this concept, a new gastric juice peptide, M.W. 40, 000, named BPC, was recently isolated. In this, a 15 amino acid fragment (BPC 157) tought to be essential for this activity was fully characterized and effectively investigated. As it had previously been demonstrated for many organoprotective agents using different models of various tissue lesions, despite the poorly understood final mechanism, practically all organ systems appear to be included into BPC beneficial activity. Relative to the reference standards, these effects have been achieved in many species using very low dosages (mostly ug and ng/kg range) after intraperitoneal, intragastrical as well as intramucosal (local) application. The effect was obvious already after one application. A long lasting activity was also demonstrated. Likewise, it was highly efficacious when applied in many experiments simultaneously with noxious agent or in the already established damage conditions, as well as chronically during a prolonged period. Therefore, it seems that BPC treatment does not share any of the so far known limitations for "conventional organoprotectors". No influence on different basal parameters and no toxicity were observed. Thus, whether these findings would provide a purposeful breakthrough into the stress thepry and whether BPC, as a likely endogenous free radical scavenger and organoprotection mediator, would be a useful prototype of a new class of drugs, organoprotective agents, remains to be seen