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The paper presents a detailed description of the oil rectification process used in upstream oil and gas plants, including the significant equipment involved. One such equipment highlighted in the study is a pressure vessel utilized as a separator to separate the liquid and gas phases. This pressure vessel has been in operation for over two decades. A thorough examination of the mentioned pressure equipment was conducted during the process evaluation. It was discovered that the internal side of the vessel, particularly its back elliptical head, had suffered extensive damage due to erosion and corrosion, emerging as the most significant cause of the deterioration. The application of RBI-estimation revealed that the vessel falls under the category of highly risk equipment, and there is a significant risk of both environmental and financial consequences associated with its potential failure (leakage). Such failure is anticipated to occur promptly in the area below the wear plate of the vessel's nozzle.

This paper presents a study and comparison of surface effects induced by picosecond and nanosecond laser modification of a Ti6Al4V alloy surface under different ambient conditions: air and argon- and nitrogen-rich atmospheres. Detailed surface characterization was performed for all experimental conditions. Damage threshold fluences for picosecond and nanosecond laser irradiation in all three ambient conditions were determined. The observed surface features were a resolidified pool of molten material, craters, hydrodynamic effects and parallel periodic surface structures. Laser-induced periodic surface structures are formed by multi-mode-beam nanosecond laser action and picosecond laser action. Crown-like structures at crater rims are specific features for picosecond Nd:YAG laser action in argon-rich ambient conditions. Elemental analysis of the surfaces indicated nitride compound formation only in the nitrogen-rich ambient conditions. The constituents of the formed plasma were also investigated. Exploring the impact of process control parameters on output responses has been undertaken within the context of laser modification under different environmental conditions. Parametric optimization of the nanosecond laser modification was carried out by implementing an advanced method based on Taguchi’s parametric design and multivariate statistical techniques, and optimal settings are proposed for each atmosphere.

Heat exchangers used in agricultural processes are mainly manufactured by three technologies: brazed copper-brass, mechanically assembled aluminum and brazed aluminum. The appropriate choice depends on various criteria: price, weight, corrosion resistance, performance in a limited volume, required pressure drops, temperature resistance, reliability, etc. Brazed aluminum is increasingly popular due to several advantages, such as resistance to high pressure and temperatures. Aluminum heat exchangers can be exposed to external and internal corrosion in various environmental conditions. Corrosion has a negative impact on the mechanical integrity and thermal performance of heat exchangers. Therefore, specific operating design parameters, as well as mechanical design characteristics, are of great importance for consideration in construction. Proper selection and design can ensure the successful and safe operation of the heat exchanger and the plant itself. The HVAC industry is directed towards the search for the best solutions in order to increase the performance, energy efficiency and durability of the equipment while reducing the costs of their production. Aluminum pipes and other aluminum components are increasingly replacing copper pipes. In this paper, application, design, assembling process and operation considerations for brazed aluminum heat exchangers used for needs in agricultural processes have presented.

Electric vehicles have become increasingly popular in recent years due to general global warming but also due to technological advances, cost reductions, increased battery charging capabilities, etc. In order to achieve the most outstanding possible efficiency of the vehicle, the thermal management system of electric vehicles must be efficient throughout the year. One of the problems is that the temperature distribution in the induction motor is not uniform, so that local overheating can occur. Thermoelectric materials make it possible to convert a temperature gradient into electrical energy. The material properties of the motor impose a temperature limit. This paper will describe the materials used for TEE and their impact on the efficiency of electric vehicles. A thermal model represents the temperature distribution within the induction motor, batteries and the entire vehicle, as well as problems that may occur during operation. Convective heat transfer plays an important role in better performance in battery cell development. In particular, the effect of temperature has a significant impact on the behaviour of the battery during acceleration and regenerative braking events. This paper investigates the temperature distribution inside the battery., Električna vozila poslednjih godina postaju sve popularnija usled opšteg globalnog zagrevanja, ali i usled napretka tehnologije, smanjenja troškova, povećavanja mogućnosti punjenja baterija itd. Za postizanje što veće efikasnosti vozila potrebno je da sistem termičkog upravljanja električnim vozilima bude efikasan tokom cele godine. Jedan od problema je da raspodela temperature u pogonskom motoru nije ravnomerna pa može doći do lokalnog pregrevanja. Termoelektrični materijali omogućavaju pretvaranje temperaturnog gradijenta u električnu energiju. Svojstva materijala motora nameću temperaturnu granicu. U ovom radu biće opisani materijali koje se koriste za termoelektrične elemente i njihov uticaj na efikasnost električnih vozila. Termalni model se koristi da bi se predstavila distribuciju temperature unutar indukcionog motora, baterija i celog vozila, kao i problemi koji se mogu javiti tokom rada. Konvektivni prenos toplote ima važnu ulogu za što bolje performanse u razvoju baterijske ćelije. Posebno, raspodela toplote ima značajan uticaj na ponašanje baterije tokom događaja ubrzanja i regenerativnog kočenja. U ovom radu se istražuje i analizira distribucija temperature unutar baterije.

In this experimental study, picosecond laser treatment was performed on a nickel-based superalloy Nimonic 263, aiming to investigate the surface effects induced by irradiation in different atmospheric conditions and, concerning changes in surface composition, regarding the possibility for improvement of its functionality. Besides the varying laser parameters, such as a number of pulses and pulse energy, environmental conditions are also varied. All surface modifications were carried out in standard laboratory conditions and a nitrogen- and argon-rich atmosphere. The resulting topography effects depend on the specific laser treatment and could be categorized as increased roughness, crater formation, and formation of the laser-induced periodic surface structures (LIPSS). Changes in the chemical surface composition are distinguished as the potential formation of the protective oxides/nitrides on the sample surface. Numerous characterization techniques analyse the resulting effects on the topography and surface parameters. The multi-response parametric optimization of the picosecond laser process was performed using an advanced statistical method based on Taguchi’s robust parameter design. Finally, the optimal parameter conditions for Nimonic 263 modification are suggested.

Heat exchangers used in agricultural processes are mainly manufactured by three technologies: brazed copper-brass, mechanically assembled aluminum and brazed aluminum. The appropriate choice depends on various criteria: price, weight, corrosion resistance, performance in a limited volume, required pressure drops, temperature resistance, reliability, etc. Brazed aluminum is increasingly popular due to several advantages, such as resistance to high pressure and temperatures. Aluminum heat exchangers can be exposed to external and internal corrosion in various environmental conditions. Corrosion has a negative impact on the mechanical integrity and thermal performance of heat exchangers. Therefore, specific operating design parameters, as well as mechanical design characteristics, are of great importance for consideration in construction. Proper selection and design can ensure the successful and safe operation of the heat exchanger and the plant itself. The HVAC industry is directed towards the search for the best solutions in order to increase the performance, energy efficiency and durability of the equipment while reducing the costs of their production. Aluminum pipes and other aluminum components are increasingly replacing copper pipes. In this paper, application, design, assembling process and operation considerations for brazed aluminum heat exchangers used for needs in agricultural processes have presented.

Cooling towers use significant amounts of water, and the cooling system is often the most efficient energy user in a building during the cooling season. Maximizing the energy efficiency of the cooling system can be significantly improved by optimizing the cleanliness of the tower heat transfer surfaces and the heat transfer surfaces of the heat exchanger cooling system. Cooling towers belong to the group of contact heat exchangers, and they are an integral part of almost every process plant, which failure can produce long-term downtime and significant material losses. Bearing in mind this fact, it is necessary to check electric motor, the fan and its components in a reliable way in order to ensure the required continuity of the process in the appropriate period of time. Previous methods of checking fan parts in accordance with the manufacturer's manuals included only visual inspection of the fan blades and checking the tightening torque of the blades for their holders. The mentioned methods have proven ineffective and insufficient from the point of view of maintenance of process plants during working life, which has led to the fan's failure and the blade holder's breakage at the point of connection with the blade. Hence, for the needs of appropriate maintenance, the conventional non-destructive methods for the assessment of surface and volumetric defects of blade holders have been applied. This methodology for checking the blade holders has been presented in detail in the paper., Kule za hlađenje koriste značajne količine vode, a sistem za hlađenje je često najefikasniji korisnik energije u zgradi tokom sezone hlađenja. Maksimiziranje energetske efikasnosti sistema za hlađenje može se značajno poboljšati optimizacijom čistoće površina za prenos toplote kule za hlađenje i površina za prenos toplote sistema za hlađenje izmenjivača toplote..Kule za hlađenje vode spadaju u grupu kontaktnih razmenjivača toplote, i sastavni su deo gotovo svakog procesnog postrojenja, čiji otkazi mogu dovesti do dugotrajnih zastoja i značajnih gubitaka materijala. Imajući u vidu ovu činjenicu, neophodno je na pouzdan način proveriti electromotor, ventilator i njegove komponente kako bi se obezbedio potreban kontinuitet procesa u odgovarajućem vremenskom periodu. Ranije metode provere delova ventilatora u skladu sa uputstvima proizvođača uključivale su samo vizuelnu proveru lopatica ventilatora i proveru momenta zatezanja lopatica za njihove držače. Pomenute metode su se pokazale neefikasnim i nedovoljnim sa stanovišta održavanja procesnih postrojenja tokom radnog veka, što je dovelo do kvara ventilatora i loma držača lopatica na mestu spoja sa lopaticom. Stoga su, za potrebe odgovarajućeg održavanja, primenjene konvencionalne nedestruktivne metode za procenu površinskih i zapreminskih defekata držača lopatica. Ova metodologija provere držača lopatica je detaljno prikazan u radu.

The use of ChatGPT possibilities in collecting relevant scientific information, at this phase of technological development shows the multi-layered of the problem of valorization of scientific sources. In this paper, the results of preliminary research on the development of knowledge on the sources of renewable energy have been presented through time, in the still unrealized space of heritological matter . Our case study refers to a scientific work „Le vide, l'énergie et la matière: Un essai de physique théorique“ by Gérard Berger., Upotreba ChatGPT mogućnosti u prikupljanju relevantnih naučnih informacija u ovoj fazi tehnološkog razvoja pokazuje višeslojnost problema valorizovanja naučnih izvora. U ovom radu prikazani su rezultati preliminarnih istraživanja o razvoju znanja o obnovljivim izvorima energije kroz vreme, u još uvek neelaboriranom prostoru heritološke predmetnosti. Studija slučaja odnosi se na delo "Le Vide, L'énergie et la Matière: Un essai de physique théorique " autora Žerara Beržea.

By considering new studies on the possibility of implementing smart materials in museum-gallery spaces which give the context for some modern models of functioning renewable energy sources, this paper examines the universality of descriptions such context. Methodologically, in the use of an analytical apparatus on the relation principle of Ars Inveniendi – Ars Combinatoria, the work is inspired by Leibniz's philosophical ideas., Razmatranjem novih studija o mogućnost primene smart materijala u muzejsko-galerijskim prostorima koji daju kontekst za neke savremene modele funkcionalizacije obnovljivih izvora energije, u ovom radu ispituje se univerzalnost deskripcije takvog konteksta. Metodološki, u korišćenju analitičkog aparata na relaciji principa Ars Inveniendi – Ars Combinatoria, rad je inspirisan Lajbnicovim filozofskim idejama.

The surface of a titanium-based alloy Ti6Al4V was subjected to modifications by a near-IR femtosecond Ti:Sapphire laser, emitting at 775 nm pulses of 200 fs duration, in single-pulse and multi-pulse regimes, with up to 400 accumulated pulses, and pulse energies ranging from 2.5 to 250 $$\upmu $$J. The whole range of induced effects is presented, from gentle ablation and pattern occurrence to substantial crater formation. Very observable laser-induced parallel periodic surface structures are reported, appearing both within the damage spot area, with low fluences, and at the peripheries of the craters, with higher fluences—but also on crater walls, and inside the crater structures. Damage threshold fluences $$({F}_{\mathrm{th}})$$and the incubation factor $$(\zeta )$$were also determined.

Savremena muzejska praksa, koja u procesu muzealizacije obnovljivih izvora energije, u prvi plan ističe ideje, a potom eksponate, pogodna je za muzejsku kontekstualizaciju solarne energije. Imajući u vidu razvoj ideja o korišćenju ove vrste energije, predmet istraživanja je kolekcija Museum of Solar Energy, u kontekstu zaštite kulturnog nasleđa. U okviru razmatranja metodoloških, naučnih i obrazovnih aspekata delatnosti ovog muzeja, uz komparativnu analizu koncepta Frances Young Tang Teaching Museum, daje se projekcija mogućeg razvoja muzeja kao realnog i virtuelnog prostora za sticanje formativnog iskustva u radu sa solarnom energijom., Contemporary Museum Practice, which in the process of musealization of renewable energy, emphasizes ideas, and then exhibits, is suitable for museum contextualization of solar energy. Given the development of ideas on using this type of energy, the subject of research is The Collection of Museum of Solar Energy, in the context of protection of cultural heritage. Within the review of the methodological, scientific and educational aspects of this museum, with a comparative analysis of the concept of Frances Young Tang Teaching Museum, we propose the possible development of the museum as a real and virtual space to acquire formative experience in working with solar energy.

Uporedo sa razvojem istraživanja obnovljivih izvora energije, poslednjih godina razvija se i moderna energetska paradigma u vezi sa različitim aspektima primene ovih izvora, odnosno energetske tranzicije. Filozofski aspekti odnose se na specifičnosti novih perspektiva posmatranja problema i načina rezonovanja u okviru tehnofilozofske tradicije, kao i u kontekstu savremenih okolnosti primene obnovljivih izvora energije. Heritološku dimenziju daje usmerenost na očuvanje civilizacijskih vrednosti i etičko ponašanje. U ovom radu u fokusu su heritološko-filozofske ideje prisutne u savremenoj akademskoj praksi., Along with the development of renewable energy research, in recent years, develop and a modern energy paradigm in relation to various aspects of the application of these sources, or energy transition. Philosophical aspects relate to the specifics of new perspectives on observation of problems and ways of resonating within the technophilosophical tradition, as well as in the context of the contemporary circumstances of the using renewable sources of energy. Heritological dimension gives focus on the preservation of civilizational values and ethical behavior. In this paper, the focus is a heritological-philosophical idea present in modern academic practice.

The paper shows preparation of inspection plan for air cooled heat exchanger in refinery. The importance of proper inspection, traceable prepared plan of inspection is discussed. The inspection of heat exchanger, according to the presented plan, includes visual testing - internal and external, ultrasound testing and liquid penetrate testing. The inspection plan is essential for maintenance the pressure equipment in refineries and is performed according to API 572 and API 510. The inspection of air cooled heat exchanger shows satisfactorily results.

Postrojenja za stabilizaciju nafte omogućavaju rekuperaciju i komercijalnu eksploataciju nafte koja se izdvaja iz gasa dopremljenog iz bušotine. Kondenzovani topli tečni ugljovodonici koji su prečišćeni iz prirodnog gasa mogu se koristiti za zagrevanje fluida koji dolazi u proces u kome se vrši njegovo razdvajanje na lakše i tečne komponente. U radu je prikazan pregled razmenjivača toplote nafta-nafta i objašnjen značaj inspekcije u pogledu održivog razvoja i zaštite životne sredine. Debljina materijala merena je ultrazvučnom tehnikom. Određivanje stepena korozije i preostalog radnog veka razmenjivača toplote izvršeni su prema API 510 i API 572 standardu. Vizuelni test je otkrio određena mehanička oštećenja i površinsku koroziju, metoda inspekcije penetrantskim metodama nije detektovala prsline u zavarenim spojevima u vreme pregleda., Plant for oil stabilisation is enable to recovery and commercial exploitation of oil which is rectified from excavated raw gas. Condensed hot liquid hydrocarbons that are separated from natural gas can be used to heat the fluid that enters the process in which it is separated into liquid and lighter components. This paper presents the inspection of an oil heat exchanger and explains the importance of inspection regarding sustainable development and environmental protection. The thickness of the material was measured by ultrasonic technique. Determination of corrosion rate and remaining life of oil-oil shell and tube heat exchanger is performed according to the API 510 and API 572 standards. The visual test revealed some mechanical damages and surface corrosion; a liquid penetrant inspection method showed no cracks at the time of inspection.

Umetnost kovanog gvožđa, vizantijska tehnika izrade predmeta, arheološko srebro srpskog srednjovekovnog blaga, predmeti od antičkog kamenja za pečate i nakit iz kolekcije Muzeja Kneza Pavla, zatim izrada relikvijara, umetnička obrada mačeva u skitskoj umetnosti, emajliranje, kopaničarstvo (rezbarenje drveta), staro srpsko zlatarstvo, kao i staro metalno posuđe srpskih vladarskih kuća, samo su neke od tema koje su bile zastupljene u časopisu Umetnički pregled, koji je u periodu od 1937-1941. godine objavljivao Muzej Kneza Pavla u Beogradu. U ovom radu, predmet istraživanja su politehnički sadržaji i način njihove tematizacije, u vezi sa istorijom, tradicijom, etnologijom i kulturom., Wrought iron art, Byzantine technique of making items, archeological silver of Serbian medieval treasures, Antique stones for seals and jewelry from the collection of the Prince Paul Museum, then, making reliquaries, art processing in Scythians swords, enamel, wood carving, old Serbian art of craft gold, as well as the old dishes metal of Serbian ruling houses, only some of the topics that were represented in the magazine “Umetnički pregled”, which is in the period from 1937-1941. published the Prince Paule Museum in Belgrade. In this paper, the subject of research are polytechnic contents and the modus of their thematization, regarding history, tradition, ethnology and culture.

Naftna platforma je velika građevina sa objektima za bušenje bušotina za istraživanje, vađenje, skladištenje i preradu nafte i prirodnog gasa koji leži u stenovitim formacijama ispod morskog dna. Bušenje na otvorenom moru predstavlja izazove za životnu sredinu. Iako, srećom, nije bilo mnogo nesreća na naftnim platformama, šteta koja nastane je ogromna i u ljudskom i u materijalnom i u smislu zaštite životne sredine. Iz tog razloga, inspekcija opreme pod pritiskom je od velikog značaja. Posude pod pritiskom mogu biti pod rizikom od degradacije materijala. Jedan od tipičnih mehanizama degradacije materijala je korozija. U ovom radu će biti prikazana važnost inspekcije opreme pod pritiskom. Na konkretnom, praktičnom primeru će biti predstavljena inspekcija cevovoda i određivanje brzine korozije i preostalog veka trajanja u cilju sprečavanja otkaza i materijalnih I ljudskih gubitaka., The oil platform is a large structure with facilities for drilling wells for exploration, extraction, storage and refining of oil and natural gas lying in rock formations under the seabed. Offshore drilling poses environmental challenges. Although, fortunately, there have not been many accidents on oil platforms, the damage that occurs is enormous, both in human and material terms, and in terms of environmental protection. For that reason, the inspection of pressure equipment is of great importance. The risk to the pipeline in service can be failure due to material degradation. One of the typical mechanisms of material degradation is corrosion. This paper will present the importance of inspection of pressure equipment. On a concrete, practical example, pipeline inspection and determination of corrosion rate and remaining life will be presented in order to prevent failures and material and human losses.

Hermeneutički i politehnički pogledi na tehnološki oblikovanu egzistenciju savremenog čoveka, ukrštaju se u politehničkom muzejskom okruženju, na planu simboličke sublimacije. U ovom radu, predmet istraživanja su operativno-tehnički aspekti prezentacije konceptualnih pozicija u stvaranju muzejskih predstava politehničnosti, a u kojima je centralno pitanje konceptualna primena u vizuelnoj predstavi mašinskih delova ili elemenata, pa i mašina u celini. Prikazane su dve studije sa Interneta, koje karakterišu različite tehnološke pristupe u materijalizaciji politehničkog promišljanja o tehnološkom univerzumu naše civilizacije., Hermeneutic and polytechnic views on the technologically shaped existence of modern man intersect in the polytechnic museum environment, in termms of symbolic sublimation. In this paper, the subject of research are operational and technical aspects of the presentation of conceptual positions in the creation of museum presentations of polytechnic, in which the central issue is the conceptual application in the visual presentation of machine parts or elements, and machines as a whole. Two studies from the Polytechnic museum in Moscow are presented, which characterize different technological approaches in the materialization of polytechnic thinking about the technological universe of our civilization.

Kolone za rektifikaciju gasa veoma su važan deo svake fabrike. Njihovi iznenadni otkazi svakodnevno uzrokuju ogromne gubitke, dok curenje tečnosti može biti veoma opasno po ljude i životnu sredinu. Iz tog razloga, pravilan dizajn kolone je od velike važnosti, kao i primena ostalih faktora bezbednosti. U ovom radu prikazano je merenje debljine zida sa ciljem da se izračuna stopa korozije i preostali vek trajanja rektifikacionih kolona. Minimalna potrebna debljina zida kolone izračunata je prema najčešće korišćenim međunarodnim standardima i analizirana je dobijena razlika., Gas rectification columns are a very important part of each onshore plant. Their sudden failures cause huge losses on a daily basis, while fluid leakage can be very dangerous to people and environment. For that reason, the proper design of the column is of huge importance, among the others safety factors as well. In this paper, the wall thickness measure is presented with the aim to calculate corrosion rate and remaining life of rectification columns. The minimum required column wall thickness was calculated according to the most commonly used international standard and the obtained difference was analyzed.

Gas rectification columns are process apparatuses which are very important part of each onshore plant. Sudden failure of these types of columns causes huge daily losses, while fluid leakage can be very dangerous for the people and hazardous for the environment. For that reason, a regular and correct examination of the column is of great importance for the continual process of leading. Together with the detailed examination of the column, a risk-based inspection was applied to maximize savings, both material, time, and costs. The expected remaining service life of rectification columns was also analyzed, while the corrosion rates were calculated according to the various international standards. The minimum required column wall thickness was calculated according to the most commonly used international standard and the obtained difference was analyzed. Detailed analysis of the total risks of the column due to potential failure is presented.

Reliable and resilient constructions are basic for ensuring the safety of various structures. The superalloys are used as constructive materials due to their superb mechanical properties and endurance. However, even these materials can have certain areas where the stress concentration is higher than expected, such as drilling holes, which are common in various structures that need additional enhancement. Surface laser modifications of the areas surrounding the holes drilled in Nimonic 263 sheets are done by pulsed picosecond and nanosecond Nd:YAG laser irradiations with pulse durations of 170 ps and lt = 8 ns, respectively. Following the laser surface treatment, the effectiveness of the enhancement was analyzed by the microhardness test and the deformation test. The results show that the deformation and stress values are decreased by 25-40 percent, showing the improvement in the resilience to deformation. The Vickers microhardness test results indicate an improvement in the Nimonic 263 microhardness. The dimensions of the microcracks are higher for the untreated material in comparison to the laser-treated material.

The paper presents a solution applied for determining the quality of the welding process in oil and gas industrial plants, as well as reliable verification of professional qualification of welding personnel. By applying the solution, welded joint quality can increase and thus the safety (especially in the field of high-pressure gas plants) and the reliability of the process in oil and gas-, petrochemical and nuclear plants, as a whole. The paper analyses safety aspects in the welding process, depending on the competence in welding and an appropriate qualification, taking into account that high levels of skill and competence are required where safety-critical items are fabricated. The results in the application of the new recertification model are presented and analysed, and it is emphasized that the areas of application of the new solution are wide, mainly applied in the oil and gas-, petrochemical industry, and the construction of nuclear plants. The application of the new model of Welders Recertification enables project savings, but also safety at work since the employer has a constant insight into the qualifications and welding capabilities of each welder.

RTI (eng: Reflectance Transformation Imaging) je računarska fotografska metoda koja snima oblik i boju površine objekta sinhrono sa osvetljavanjem iz različitih uglova. RTI, takođe, dozvoljava matematičko modelovanje površine i atributa boja posmatranog objekta. Funkcije poboljšanja RTI otkrivaju površinske informacije koje se ne uočavaju pri normalnom osvetljenju i ispitivanju. U radu je prikazano jedno savremeno rešenje hardvera i softvera aparature za izradu serije fotografija nad jednom površinom osvetljenom iz više pravaca sekvencijalno. Dalja obrada vrši se uz pomoć javno dostupnog softvera RTIViewer. Opisani sistem je korišćen za RTI snimanje površina, dat je prikaz ispitivanja površine novčića i objašnjena prednost i mogućnost primene u mašinstvu i ostalim tehničkim naukama., RTI (Reflectance Transformation Imaging) is a computer photographic method that captures the shape and color of the surface of an object synchronously with lighting from different angles. RTI also allows mathematical modeling of the surface and color attributes of the observed object. RTI enhancement functions reveal surface information that is not observed under normal lighting and testing. The paper presents a modern solution of hardware and software for the production of a series of photographs over a single surface illuminated from several directions sequentially. Further processing is performed thanks to the publicly available RTIViewer software. The described system was used for RTI imaging of surfaces, a presentation of the examination of the surface of coins was given and the transferability and possibility of application in mechanical engineering and other technical sciences were explained.

Owing to their good mechanical properties, titanium based alloys are used for machine parts and devices that operate in demanding regimes and environmental conditions. Laser shock peening (LSP) is an innovative technique for improvement of the surface and mechanical characteristics of the material. In this paper, LSP is employed for additional improvement of already good characteristics of Ti- alloy. Laser shock peening is performed on alloy surface, with and without protective and transparent layer and obtained microstructure, surface characteristics and mechanical properties are compared. LSP improved the surface topology and microhardness of material, producing overall better results when the Ti-alloy surface was coated by transparent and protective layer.

U ovom radu, proučavan je uticaj parametara određenih procesa laserske tehnike obrade materijala superlegure Nimonic 263 - bušenje, rezanje, zavarivanje i mehanička obrada laserom. Bušenje i zavarivanje su vršeni na laseru Nd:YAG laserom model HTS Mobile LS-P160. Prilikom bušenja rupa varirani su parametri frekvencije impulsa (5 Hz, 7Hz i 9 Hz) i dužine trajanja impulsa (1,8 ms do 3,6 ms). Ispitivana je mikrostruktura i određene su geometrijske i metalurške karakteristike rupa dobijenih ovim parametrima, na osnovu čega je izvršena optimizacija parametara obrade. Rezanje je izvedeno na laseru tipa Bistronic laser, (2000), BISTAR 3015. Varirani su parametri srednje snage lasera, brzina lasera, pritisak gasa i položaj fokusa. Na osnovu dobijenih geometrijskih karakteristika rezova i površinske morfologije diskutovani su i određeni optimalni parametri. Laserom zavareni spojevi limova legure Nimonik 263 su, osim mikroskopskih i profilometrijskih ispitivanja površina, ispitivani i metodom sa razaranjem. Prilikom laserskog deformacionog ojačavanja uzorci su bili izloženi laserskom svetlu na talasnoj dužini od 1064 nm i 532 nm, sa brojem akumuliranih impulsa: 50, 100 i 200. U svim delovima eksperimenta strukturna analiza superlegure Nimonic 263 izvedena je pomoću svetlosne mikroskopije (SM), skenirajuće elektronske mikroskopije (SEM) i EDS-analize. Merenja mikrotvrdoće vršena su pomoću metode Vikersa pod opterećenjem od 9,81N. Profilometrija je izvedena na beskontaktnom profilometru Zygo NewView 7100., In this paper, the influence of parameters of laser processing (drilling, cutting, welding and laser shock peening) on microstructure of superalloy Nimonic 263 are investigated. Drilling and welding process are carried out on the Nd: YAG laser model LS-HTS Mobile P160. When drilling the holes, the parameters of pulse frequency (5 Hz, 7 Hz and 9 Hz) and the pulses duration (1.8 ms to 3.6 ms) are varied. The microstructure is investigated and geometrical and metallurgical characteristics of the holes are determined.Cutting is carried out on the laser BISTRONIC, (2000), BISTAR 3015. The parameters that were varied are as follows: the average laser power, laser velocity, the pressure of the assisting gas and the focus position. Based on the geometrical characteristics of the cuts and surface morphology the optimal parameters are discussed and defined. The laser welded joints of Nimonic 263, in addition to microscopic examination and surface profilometry, were subjected to the destructive testing. During the laser shock peening, the samples were exposed to laser light at a wavelength of 1064 nm and 532 nm, with the number of accumulated pulses 50, 100 and 200. The operating laser was Nd: YAG EKSPLO, SL212P model. Structural analysis of Nimonic 263 was carried out using light microscopy, scanning electron microscopy and EDS analysis. Microhardness measurements were carried out using the Vickers method under load of 9,81N. Profilometry was performed on a contactless profilometer Zygo Newview 7100.

In this paper, the influence of parameters of laser processing (drilling, cutting, welding and laser shock peening) on microstructure of superalloy Nimonic 263 are investigated. Drilling and welding process are carried out on the Nd: YAG laser model LS-HTS Mobile P160. When drilling the holes, the parameters of pulse frequency (5 Hz, 7 Hz and 9 Hz) and the pulses duration (1.8 ms to 3.6 ms) are varied. The microstructure is investigated and geometrical and metallurgical characteristics of the holes are determined.Cutting is carried out on the laser BISTRONIC, (2000), BISTAR 3015. The parameters that were varied are as follows: the average laser power, laser velocity, the pressure of the assisting gas and the focus position. Based on the geometrical characteristics of the cuts and surface morphology the optimal parameters are discussed and defined. The laser welded joints of Nimonic 263, in addition to microscopic examination and surface profilometry, were subjected to the destructive testing. During the laser shock peening, the samples were exposed to laser light at a wavelength of 1064 nm and 532 nm, with the number of accumulated pulses 50, 100 and 200. The operating laser was Nd: YAG EKSPLO, SL212P model. Structural analysis of Nimonic 263 was carried out using light microscopy, scanning electron microscopy and EDS analysis. Microhardness measurements were carried out using the Vickers method under load of 9,81N. Profilometry was performed on a contactless profilometer Zygo Newview 7100., U ovom radu, proučavan je uticaj parametara određenih procesa laserske tehnike obrade materijala superlegure Nimonic 263 - bušenje, rezanje, zavarivanje i mehanička obrada laserom. Bušenje i zavarivanje su vršeni na laseru Nd:YAG laserom model HTS Mobile LS-P160. Prilikom bušenja rupa varirani su parametri frekvencije impulsa (5 Hz, 7Hz i 9 Hz) i dužine trajanja impulsa (1,8 ms do 3,6 ms). Ispitivana je mikrostruktura i određene su geometrijske i metalurške karakteristike rupa dobijenih ovim parametrima, na osnovu čega je izvršena optimizacija parametara obrade. Rezanje je izvedeno na laseru tipa Bistronic laser, (2000), BISTAR 3015. Varirani su parametri srednje snage lasera, brzina lasera, pritisak gasa i položaj fokusa. Na osnovu dobijenih geometrijskih karakteristika rezova i površinske morfologije diskutovani su i određeni optimalni parametri. Laserom zavareni spojevi limova legure Nimonik 263 su, osim mikroskopskih i profilometrijskih ispitivanja površina, ispitivani i metodom sa razaranjem. Prilikom laserskog deformacionog ojačavanja uzorci su bili izloženi laserskom svetlu na talasnoj dužini od 1064 nm i 532 nm, sa brojem akumuliranih impulsa: 50, 100 i 200. U svim delovima eksperimenta strukturna analiza superlegure Nimonic 263 izvedena je pomoću svetlosne mikroskopije (SM), skenirajuće elektronske mikroskopije (SEM) i EDS-analize. Merenja mikrotvrdoće vršena su pomoću metode Vikersa pod opterećenjem od 9,81N. Profilometrija je izvedena na beskontaktnom profilometru Zygo NewView 7100.

Hydrothermally obtained Mg3Ta208 pseudo-binary nanomaterial from MgO and Ta2O5 (3:1) precursors was deposited using the pulsed laser deposition (PLD) technique on carbon steel disks. The PLD main processes parameters, i.e. the pulse energy and the deposition time were varied in order to determine the combination that ensures the best corrosion inhibition. Morphological investigations were carried out (scanning electron microscopy and atomic force microscopy). The anticorrosive properties of the deposited layers were studied in 0.3 M NaCI saline solution. The best anticorrosive protection was observed in the case of the deposited layers on carbon steel disk using the lower energy, i.e. 10mJ for a deposition time of 60s, i.e. 61.94 % inhibition efficiency.

The Pressure Equipment Directive (PED) and Regulations on Technical Requirements for Designing, Manufacturing and Conformity Assessment of Pressure Equipment bring a number of changes to the design of pressure equipment in relation to the Technical Regulations for Stable Pressure Vessels, 1983. Among the most important changes are the essential safety requirements for pressure equipment. The changes in the formula, for all materials, for calculating the allowable stresses, as well as the change in the value of the test pressure, the new Regulations use the 1.0% proof strength as the relevant value for calculating the permissible membrane stress and thickness of pressure equipment walls. In this paper, the differences in the allowable stresses, the required wall thicknesses, and the approximate savings in the material in the case of a milk reservoir, calculated according to the requirements of the Directive and the new Regulations on one hand, and the old Regulations on the other, are presented. © 2018 The Author.

The steels fracture toughness was measured at two different temperature T= - 60°C and T = -90°C, at v=0.02 mm/min and v=0.5 mm/min. The following steels: CrMoV, 20MnMoNi55, A533B and A508 were tested with three different sizes of CT specimens 50 and 100 and 200. Those steels are weldable, although the authors investigated the fracture behaviour of base material. In order to satisfy statistical analyses, a large number of specimens were tested. Fracture behaviour has turned out to be typical, S-shaped curve for transitional fracture at low temperatures. Apart from the other variables, specimen’s width significantly affects measured toughness. Smaller specimens, CT50, might be considered of upper bound reliability while the CT200 specimens were shown to be the most conservative. In this way it has been shown that wider specimens are more reliable in a fracture assessment of the examined steels. In this paper, the fracture probabilities of specimens in function of fracture toughness were determined as well, and it could be concluded that the widest specimens are the most likely to be broken for the same values of the fracture toughness.

Laser shot peening (LSP) of material strengthening is nowdays widely used method in various branches of industry. In this paper are presented comparative exeminations of specimen made of NIMONIC and strengthened specimen on which laser shot peening method was performed. Specimens were made as thin plates with holes. Macrostructural surface tests were performed around the specimens holes with different magnifications for both specimens as well as certain damages on the specimens. 3D images of specimens damages provide insights into the its dimensions. In addition, the roughness of non-strengthed and strengthed specimens was also performed. Hardness tests using the Rockwell C method of both specimens show a difference in the hardness of both samples and the main characteristics of the laser shot peening method. Also, the analysis on how the damage of samples could represent the location of initial cracks that could cause failure of the specimens or generally machine part is given as well.

The Pressure Equipment Directive (PED) and Regulations on Technical Requirements for Designing, Manufacturing and Conformity Assessment of Pressure Equipment bring a number of changes to the design of pressure equipment in relation to the Technical Regulations for Stable Pressure Vessels, 1983. Among the most important changes are the essential safety requirements for pressure equipment. The changes in the formula, for all materials, for calculating the allowable stresses, as well as the change in the value of the test pressure, the new Regulations use the 1.0% proof strength as the relevant value for calculating the permissible membrane stress and thickness of pressure equipment walls. In this paper, the differences in the allowable stresses, the required wall thicknesses, and the approximate savings in the material in the case of a milk reservoir, calculated according to the requirements of the Directive and the new Regulations on one hand, and the old Regulations on the other, are presented.

Road transport is the significant and inevitable part of the modern society. Its accelerated expansion is recognized as one of the causes for the increased air pollutant emissions (CO, NOx, NMVOC, PM2.5, and CO2). Therefore, the priorities of the future development of heavy-duty vehicles and their equipment are the reduction of the fuel consumption and reduction of the exhaust gases emissions. In this paper, the monitored emissions of heavy-duty vehicles of various technologies, that use diesel as fuel, have been analyzed by using the COPERT program. The analysis shows that Euro 5 vehicles emit 29% less harmful substances compared with Euro 3 vehicles.