Lakštinėse spausdinimo mašinose spausdinant spalvotus atvaizdus svarbu mašinos atskirose sekcijose atspaudų sutapimą išlaikyti šimtųjų milimetro dalių tikslumu. Be to, spausdinamų atvaizdų geometrinis nesutapimas abiejose lapo pusėse neturi viršyti 0,1 mm. Viena iš pagrindinių nesutapimo priežaščių yra mechaninio krumpliaratinio perdavimo mechanizmo iš vienos sekcijos į kitą sukamieji virpesiai, kuriuos sukelia krumpliaračių paklaidos ir pasipriešinimo momentų pokyčiai tarp ofsetinių ir forminių cilindrų. Darbe analiziniu – kompiuteriniu būdu nagrinėjama šių virpesių įtaka lapo perdavimo tikslumui. Konkrečiam tyrimui pasirinkta „Heidelberg“ spausdinimo mašina GTO 52, tačiau darbe taikoma tyrimo metodika tinka ir kitoms mašinoms. Sudarytas elektros pavara valdomo lapų perdavimo mechanizmo dinaminis modelis su 16 laisvės laipsnių. Sistemos matematinis modelis (virpesių lygtys ir struktūrinė schema) sudarytas kompiuterizuotu būdu MATLAB/SIMULINK programų terpėje, kurioje atliktas sistemoje vykstančių dinaminių procesų modeliavimas. Pavaroje kylančios paklaidos apibūdinamos sukamųjų virpesių amplitudinėmis – dažninėmis charakteristikomis. Nagrinėjama šių charakteristikų pobūdžio, rezonansinių virpesių ir jų dažnių įtaka lapo perdavimo paklaidos dydžiui. / It is important in printing machines to maintain very high print quality (hundredths of a millimeter) in printing colorful prints. Also mismatches of prints in both sides of sheet must not exceed 0,1 millimeter. One of the reasons of mismatching is mechanical gear transfers mechanisms, from one printing unit to another, rotational oscillations, which are generated by gear errors and resistance moment changes between offset and print cylinder. These oscillations influence to sheet transfer accuracy are examined in analytical – computer way. For particular examination there was selected “Heidelberg” printing press GTO 52, but the examination method can be used for other presses. There was formed dynamic model with 16 degrees of freedom. Mathematical model of the system (oscillation equations and flowchart) was formed with MATLAB/SIMULINK program, in which dynamical process modeling was done. Errors in drive described as an amplitude frequency response. There was examined these response nature, resonant oscillations and its frequency influence to sheets transfer errors size.

Baigiamajame magistro darbe nagrinėjama tiesioginė šilumos atgavimo funkcija iš šilumos siurblio darbo ciklo ir jos pritaikomumas Lietuvos klimatinėmis sąlygomis. Apžvelgiami naudojamų šalčio mašinų tipai, technologiniai tiesioginio šilumos atgavimo inžineriniai sprendmiai. Taip pat detaliai paaiškinamas šilumos siurblio darbo ciklas ir tiesioginio šilumos atgavimo funkcijos veikimo principas. Taip pat šilumos atgavimo founkcija nagrinėjama konkrečiame jau egzistuojančiame administracinės paskirties pastate, kuriame sumontuota vandeninė šalčio mašina. Nustatomas šalčio mašinos darbo režimų grafikas skaičiuojamąjį Liepos mėnesį. Dviejomis nepriklausomomis kompiuterinėmis programomis sumodeliuojami šalčio mašinos freono konturų darbo ciklai. Pagal gautus rezultatus parenkami ir sumodeliuojami šilumos atgavimo šilumokaičiai ir randamos įmanomos atgauti šilumos galios ir šilumos kiekiai, kurie palyginami su pastato karšto vandens poreikiais ir atliekamas ekonominis šilumos atgavimo funkcijos vertinimas. Gauti rezultatai patvirtina, kad tokio tipo šilumos atgavimas didina pastato energijos vartojimo efektyvumą ir padeda taupyti pinigus. Taip pat nustatyta, kad Lietuvos klimatinėmis sąlygomis šilumos atgavimas įmanomas tik šiltuoju metų sezonu, kai pastate yra vėsos poreikis, tačiau nepaisant to, metiniai sutaupymai yra pakankamai dideli, todėl tiesioginis šilumos atgavimas yra efektyvi mikroklimato sistemų optimizavimo priemonė. / In this Master thesis a direct heat recovery option on the air cooled chiller and its availability in Lithuanian climate has been investigated. Also the review of chiller range, direct heat recovery technological issues and direct refrigerant vapor compression cycle has been explained in detail. Also the heat recovery option has been investigated in the specific administrative building with the chiller already installed. Chiller cooling chart has been calculated for the selected time period – a month of July. Chiller refrigerant circuits were modeled by using two independent computer applications. In accordance with the calcultated results, plate heat exchangers were designed. Possible amount of recovered heat was found and compared with building‘s heat demand for hot domectic water supply. The economical evaluation of heat recovery option was carried out. The results confirmed that the heat recovery option discussed in the thesis can increase energy consumption efficiency. Despite the fact that heat recovery in Lithuanina climate is only possible during the warm season, annual savings on energy consumption are sufficiently high to make the heat recovery measure an attractive option.

<p>U tezi je prikazana analiza pogona sa šestofaznom asimetričnom<br />asinhronom mašinom koja se napaja iz šestofaznog invertora.<br />Predložen je novi način upravljanja šestofaznim invertorom kojim<br />su rešeni nedostaci do sada predloženih tehnika upravljanja a koji<br />se pre svega ispoljavaju kroz dva aspekta: nekontrolisano generisanje<br />dodatnih gubitaka i teška implementacija u komercijalno dostupne<br />digitalne kontrolere. Rezultati svih teorijskih analiza i navoda su<br />dokazani računarskim simulacijama i eksperimentalnim putem.<br />Eksperimentalna verifikacija je ostvarena korištenjem<br />laboratorijskog prototipa koji se temelji na dSPACE kontrolnom<br />sistemu.</p> / <p>Doctoral thesis shows the analysis of the dual three-phase induction machine<br />drive. A novel way of driving of the six-phase inverter is proposed. A<br />proposed method solves disadvantages of currently proposed driving<br />techniques which are manifested in two aspects: the uncontrolled generation<br />of additional losses and difficult implementation in commercially available<br />digital controllers. The results of theoretical analysis and the statements are<br />proven by computer simulation and experimentally. Experimental verification<br />is achieved using a laboratory prototype that is based on dSPACE control<br />system.</p>

There are widely used computers in agricultural mobile technique, which show important parameters of work process and its quality in. It is important a good illumination of workplace for quick and correct information identification from the VDT’s. There are forming different levels of illumination in agricultural technique cabins when they are working at the field. Those levels are fluctuating and operator’s eye should adapt to them compulsory. Operator’s vision feels fatigue because of those processes and work becomes not so effective. There are assessed in the work, that luminance increase on the VDT screen, as do illumination level in the cabins of agricultural mobile technique and as a result of this process, contrast reduces and visibility become worse. In experiment, there was researched, that tasks were performed quicker, when illumination was 300 -500 lx, and slower, when - 900-1200 lx. There are assessed the response time dependence on illumination level model , which helps to calculate the duration of operator’s watching, which influences the results of work quality and safety.

<p>U radu se razmatra problematika ponašanja cilindrično valjkastih ležaja za uležištenje glavnih vretena mašina alatki i osovinskog sklopa vučenih vozila na železnici. Za definisano konstrukciono rešenje uležištenja sklopa glavnog vretena izvršena su eksperimentalna ispitivanja toplotnog ponašanja čime su provereni i potvrđeni rezultati računarskog modelovanja (2D i 3D).<br />U prvom poglavlju polazi se od značaja cilindrično valjkastih ležaja za uležištenje sklopova glavnih vretena i osovinskog sklopa vučenih vozila na železnici.<br />Konstrukcioni parametri valjkastih ležaja opisani su i objašnjeni u drugom poglavlju.<br />U trećem poglavlju izvršen je pregled stanja u oblasti u dva pravca: ponašanje sklopova glavnih vretena i osovinskih sklopova na železnici. Literaturni izvori su grupisani na one koji se bave problematikom statičkog, toplotnog ponašanja i oštećenjima ležaja.<br />Matematički modeli za analizu statičkog, toplotnog ponašanja, veka ležaja kao i programsko rešenje za određivanje veka ležaja dati su u okviru četvrtog poglavlja. Prikazan je opšti algoritam ponašanja cilindrično valjkastih ležaja, kao i agoritmi statičkog, toplotnog ponašanja i veka ležaja. Dati su modeli za određivanje nelinearne krutosti u radijalnom pravcu za valjkaste ležaje. Na osnovu Ševalove teorije rasporeda opterećenja razvijen je nelinearni model generisanja toplote u ležaju.<br />U petom poglavlju izvršeno je računarsko modelovanje statičkog i toplotnog ponašanja sklopa glavnog vretena uležištenog cilindrično valjkastim dvoredim ležajem. Analizirani su modeli dvodimenzionog i trodimenzionog sklopa glavnog vretena i određene su vrednosti temperature na vrhu vretena. Veličina konačnih elemenata imala je zanemarljiv uticaj na rezultate toplotnog ponašanja. U okviru ovog poglavlja ukazuje se na činjenicu da je predikcija toplotnog ponašanja mašine alatke uslovljena ponašanjem odgovarajućih sklopova, a posebno sklopa glavnog vretena.<br />Definisanje svih izvora generisanja toplote u osovinskom sklopu kao i njihova analiza izvršeni su u okviru poglavlja šest. Potvrđena je hipoteza da na temperaturu ležaja zanemarljiv uticaj imaju generana toplota usled kotrljanja točka po šini i generisana toplota usled kočenja u odnosu na temperaturu koja se generiše u ležaju usled obrtanja i opterećenja.<br />Sedmo poglavlje odnosi se na eksperimentalna istraživanja toplotnog ponašanja konstrukcionog rešenja sklopa glavnog vretena uležištenog cilindrično valjkastim dvoredim ležajem. Za eksperimentalna istraživanja korišćeni su savremeni merni instrumnti za merenje temperature kontaktnim i bezkontaktnim metodama.<br />Uticaj generisane toplote usled kotrljanja točka po šini i usled kočenja eksperimentalno je ispitivan termovizijskom kamerom i prikazan u poglavlju osam.<br />Na kraju je u poglavlju devet izvršena analiza eksperimentalnih i računarskih rezultata ponašanja valjkastih ležaja za glavna vretena, kao i analiza rezultata računarskog modelovanja ležaja za osovinske sklopove vučenih vozila na železnici.<br />Deseto poglavlje sadrži zaključke, na osnovu rezultata pojedinih poglavlja i izvedenih istraživanja. Nakon toga dati su pravci budućih istraživanja.<br />Jedanaesto poglavlje sadrži pregled korišćene literature, koju čini 135 literaturnih naslova od kojih je određeni broj citiran u radu.</p> / <p>The paper deals with the problem of behavior of cylindrical roller bearings for<br />loosening the main spindles of machine tools and the axle assembly of towed<br />vehicles on the rail. For the defined constructional arrangement of the<br />mounting of the main spindle assembly experimental tests of thermal<br />behavior were performed which confirmed and confirmed the results of<br />computer modeling (2D and 3D).<br />The first chapter starts from the significance of cylindrical roller bearings for<br />the installation of the main spindle assemblies and the axle assembly of<br />towed vehicles on the rail.<br />The construction parameters of roller bearings (external and internal bearing<br />geometry and bearing lubrication) are described and explained in the second<br />chapter.<br />The third chapter was conducted review of the state in the field in two<br />directions: the behavior of the main spindle assemblies and axle assemblies<br />on the rail. The papers are grouped into those dealing with problems of<br />static, thermal behavior and bearing damage.<br />Mathematical models for the analysis of static, thermal behavior, bearings life<br />as well as the software solution for determining the bearing life are given in<br />the fourth chapter. A general algorithm behavioral for cylindrical cylindrical<br />bearings, as well as and algorithm static, thermal behavior and bearing life.</p><p>Models are given for determining nonlinear stiffness in the radial direction for<br />roller bearings. Based on Sjov&auml;ll&#39;s theory of load distribution, a nonlinear<br />model of heat generation in a bearing is developed.<br />In the fifth chapter, a computer modeling of the static and thermal behavior of<br />the main spindle assembly is carried out with a double row cylindrical roller<br />bearing. The two-dimensional and three-dimensional models of the main<br />spindle were analyzed and the temperature values at the top of the spindle<br />were determined. The size of the finite elements had a negligible impact on<br />the results of thermal behavior. Within this chapter, it is pointed out that the<br />prediction of the thermal behavior of the machine tool is conditioned by the<br />behavior of the corresponding assemblies, and in particular the main spindle<br />assembly.</p><p>The definition of all sources of heat generation in the axle as well as their<br />analysis were carried out under Chapter six. The hypothesis was confirmed<br />that the negligible impact on the bearing temperature is due to generating<br />heat due to rolling the wheel along the rail and generated heat due to braking<br />relative to the temperature generated in the bearing due to rotation and load.<br />Chapter Seven refers to experimental investigations of the thermal behavior<br />of the construction of the main spindle assembly with cylindrically cylindrical<br />two-row bearing. For experimental measurements were used modern<br />measurement instruments for temperature measurement by contact and<br />without contact methods.<br />The influence of generated heat due to rolling of the wheel along the rail and<br />due to braking was experimentally tested by a thermal camera and shown in<br />chapter eight.<br />In the end, in chapter nine, an analysis of the experimental and computer<br />results of the behavior of roller bearings for the main spindles was<br />performed, as well as an analysis of the results of computer modeling of<br />bearings for axle assemblies of towed vehicles on the rail.<br />Chapter ten contains conclusions, based on the results of individual chapters<br />and research carried out. After that, the directions of future research are<br />given.<br />Chapter eleven contains an overview of the used literature, made up of 135<br />literary titles, of which a certain number is cited in the paper.</p>