198 research outputs found
When is Containment Decidable for Probabilistic Automata?
The containment problem for quantitative automata is the natural quantitative generalisation of the classical language inclusion problem for Boolean automata. We study it for probabilistic automata, where it is known to be undecidable in general. We restrict our study to the class of probabilistic automata with bounded ambiguity. There, we show decidability (subject to Schanuel's conjecture) when one of the automata is assumed to be unambiguous while the other one is allowed to be finitely ambiguous. Furthermore, we show that this is close to the most general decidable fragment of this problem by proving that it is already undecidable if one of the automata is allowed to be linearly ambiguous
Optimizacija vremena zamjene vatrostalne obloge na segmentnim peÄima
The goal of the study is to establish the influence of temporal wearing of refractory lining on energy losses of the furnaces by conducting heat through the furnaces walls. Object of the study were sectional furnaces, type SELAS, situated in the seam tubes production line in Željezara Sisak, Croatia. In order to reduce production costs, it was attempted to define the timely replacement of refractory lining by the criteria of comparing the costs resulted by heat loss through the furnace lining with the costs of refractory lining replacement. Data for the calculation of heat losses was obtained by use of the infrared camera.Rad je izraÄen s ciljem da se utvrdi utjecaj vremenskog troÅ”enja vatrostalne obloge na energetske gubitke provoÄenjem topline kroz ziÄe peÄi. Kao objekt istraživanja odabrane su segmentne peÄi tipa SELAS, koje se nalaze u valjaonici Å”avnih cijevi Željezare Sisak. U cilju smanjenja proizvodnih troÅ”kova pokuÅ”ala se odrediti pravovremena zamjena vatrostalne obloge pojedinog segmenta prema kriteriju usporedbe poveÄanih proizvodnih troÅ”kova, nastalih poveÄanjem energetskih gubitaka provoÄenjem topline kroz ziÄe peÄi, s troÅ”kovima zamjene vatrostalne obloge. Za proraÄun gubitaka topline koristili su se podaci dobiveni snimanjem infracrvenom kamerom
TermofiziÄka svojstva serpentinita
In this article serpentinite from Banovina, Croatia, was studied. The antigorite is main mineral constituent of that rock. The dilatation curve shows that the first contraction of sample is coursed by dehydratation of antigorite at nearly 660Ā°C. In spite of this, the second contraction of sample, which begines at nearly 860Ā°C, is incident with olivine phase formation. The morphology of the serpentinite before and after thermal treatment was observed with the optical microscope. Image of serpentinite before thermal treatment is characterized by inclusions of olivine as primary mineral left as residue in process of serpentinization. Image of serpentinite after thermal treatment was changed by water disappear. The first thermal treated and than milled serpentinite has better properties than the first milled and than thermally treated serpentinite.U ovom radu istraživan je serpentinit s nalaziÅ”ta na Banovini u Hrvatskoj. U toj mineralnoj sirovini prevladavajuÄi mineral je antigorit. Dilatacijska krivulja ukazuje da je prva kontrakcija uzorka uzrokovana dehidratacijom antigorita na približno 660Ā°C. Nasuprot tome, na drugu kontrakciju uzorka koja poÄinje pri približno 860Ā°C utjeÄe stvaranje olivina. Morfologija serpentinita prije i poslije termiÄke obradbe promatrana je optiÄkim mikroskopom. Izgled serpentinita prije termiÄke obradbe karakteriziran je ukljuÄcima olivina kao primarnog minerala zaostalog u procesu serpentinizacije. Izgled serpentinita poslije termiÄke obradbe promijenio se uslijed eliminacije vode. Prvo termiÄki obraÄen te potom mljeven serpentinit ima bolje karakteristike od prvo mljevenog, a potom termiÄki obraÄenog serpentinita
Pokazatelji rada kružne peÄi u restriktivnim uvjetima proizvodnje
The heating operation of the rotating-hearth furnace involving semi-finished steel products was analysed, and specific heat consumption was determined as a function of furnace productivity. The aim was to find out how a change in productivity, which is not accompanied by a modification of the thermal regime, can affect the heating quality and surface oxidation of products.Analizirana je provedba zagrijavanja ÄeliÄnih poluproizvoda u kružnoj peÄi i odreÄena je specifiÄna potroÅ”nja topline u ovisnosti o proizvodnosti peÄi. Istražen je utjecaj promjene proizvodnosti kružne peÄi pri nepromijenjenom toplinskom režimu na kvalitetu zagrijavanja ÄeliÄnih poluproizvoda i na oksidaciju njihove povrÅ”ine
Effect of glycerol content and pH value of film-forming solution on the functional properties of protein-based edible films
The work is concerned with the effects of glycerol content and pH value of film forming solution on the functional properties of protein-based films. The films were produced of chicken breast proteins, dissolved under either acidic (pH 3) or alkaline (pH 11) conditions, with different concentrations of glycerol (35%, 50% and 65% w/w of protein content). Glycerol content affected significantly mechanical properties, water vapor permeability, color at pH 3 and film solubility (p<0.05). The pH value had significant influence on light transmission, color, transparency and film solubility (p<0.05). Considering the results of mechanical properties and film solubility, the obtained films are in the acceptable range for the use as a packaging material. It was estimated that water vapor permeability, color, light transmission and transparency need to be improved for the application
Utjecaj brzine hlaÄenja na svojstva kalibrirnog valjka od legiranog željeznog lijeva
Directional heat transfer was investigated by temperature measurements in the casting and in the mould using thermocouples. Measurements were performed in operating conditions during pouring, solidification, and cooling of the casting. Total measurement time was 35,5 hours. After cutting, specimens were extracted for metallographic and hardness testing. Test results provided confirmation of directional heat transfer (directional cooling) that would ensure acquirement of a desired casting structure and mechanical properties.Usmjereni prijenos topline u odljevku i kalupu praÄen je mjerenjem temperature termoparovima tijekom ulijevanja taljevine u kalup, skruÄivanja i hlaÄenja odljevka. Ukupno trajanje mjerenja iznosilo je 35,5 sati nakon Äega je odljevak izrezan i uzeti su uzorci za metalografsku analizu i mjerenje tvrdoÄe. Rezultati ovih ispitivanja potvrdili su usmjereno odvoÄenje topline (usmjereno hlaÄenje) Å”to osigurava dobivanje željene mikrostrukture i mehaniÄkih svojstava odljevka
Analiza procesa izgaranja u peÄi za taljenje aluminija
The composition of gaseous combustion product leaving the chamber of aluminium melting furnace in TLM Å ibenik was investigated by measurements and numerical analysis in order to reduce the fuel consumption and increase the capacity of the existing furnace. Investigations were motivated by the fact that the actual specific fuel consumption was considerably higher and the actual furnace production was considerably lower than the design values according to the furnace technical documentation and the previous reached values in practice.Sastav plinovitih produkata izgaranja koji napuÅ”taju radni prostor peÄi za taljenje aluminija u TLM Å ibenik je istraživan mjerenjima i numeriÄkom analizom u cilju da se smanji potroÅ”nja goriva i poveÄa kapacitet postojeÄe peÄi. Istraživanja su bila motivirana Äinjenicom da je stvarna specifiÄna potroÅ”nja goriva znatno veÄa, a kapacitet peÄi znatno manji od projektiranih vrijednosti prema tehniÄkoj dokumentaciji peÄi i prethodno u praksi postignutih vrijednosti
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