For the purpose of contributing to sustainable machining, the aim was to investigate the turning ... more For the purpose of contributing to sustainable machining, the aim was to investigate the turning of martensitic stainless steel X20Cr13 under alternative cooling and lubrication techniques. The minimum quantity lubrication technique in combination with the vortex tube cooling, as the determined optimal cooling method using the Taguchi-based entropy weighted grey relational analysis (compared to emulsion and minimum quantity lubrication technique) in previous research when turning martensitic stainless steel X20Cr13, were applied in this research in accordance with the Box–Behnken design. The aim is to investigate, when applying the optimal cooling condition (minimum quantity lubrication + vortex) with the Box–Behnken design, which parameters have a significant influence on reducing the surface roughness parameters Ra and Rz and also on the tool life (T). The cutting speed (vc = 260, 290 and 320 m/min), feed rate (f = 0.3, 0.35 and 0.4 mm/rev) and depth of cut (ap = 1, 1.5 and 2 mm) ...
Quality control of welded joint is an indispensable part of the welding production process. As pa... more Quality control of welded joint is an indispensable part of the welding production process. As part of spot resistance welding group, cross-wire welding process showed great application for welding of products for everyday usage. The non-contact quality control checking is fit for purpose due to specific characteristics of welded products that consist of two cross welded wires or a combination of wires and strips. This work proposes a new method for detecting and measuring of required dimensional parameters, but also founds its applicability for other products if required. A crucial parameter of this research is the height of welded joint, which is necessary for calculating the penetration of the wire into the wire. The proposed measuring method with a reconfigurable measuring system is explained in this paper. The main component of this system is using a machine vision system, which has become an indispensable part of industrial metrology and is considered one of the industry 4.0 c...
Provođenje projekta remonta kao najznačajnijeg poduhvata održavanja putem projektnog zadatka izni... more Provođenje projekta remonta kao najznačajnijeg poduhvata održavanja putem projektnog zadatka iznimno je složeno te nerijetko završava neuspjehom. Dostupna literatura u obliku knjiga i znanstveno-stručnih radova temelji se najčešće na osobnim iskustvima autora te na empirijskim podacima bez značajne znanstvene metodološke analize. Takvi podaci su vrlo često subjektivni, značajni kao smjernice u istraživanju, ali znanstveno neutemeljeni. Jedan od razloga nedostupnosti literature o projektima remonta je upravo složenost znanstvenog područja koje objedinjava tematiku upravljanja održavanjem, kvalitetom i projektima. Svrha i ciljevi ovoga rada su definiranje koncepta modela osiguranja kvalitete upravljanja projektima remonta rafinerijskih postrojenja. Definiranje koncepta modela temelji se na šest varijabli međusobno povezanih putem pet hipoteza. Svih pet hipoteza modela testirano je logističkom regresijom. Dobiveni rezultati potvrdili su međuodnos varijabla te su sve hipoteze potvrđene....
Surface cracks in butt-welded joints usually occur in places with increased stress concentrations... more Surface cracks in butt-welded joints usually occur in places with increased stress concentrations. The stress concentration factor (SCF) can be calculated using an empirical equation, with five geometric parameters of a butt-welded joint (thickness of the base material, toe radius, weld toe angle, weld width, and reinforcement height). However, in an industrial environment, it is impractical and sometimes even impossible to measure all five geometric parameters with sufficient accuracy. In this study, eight experiments on butt-welded joints were performed. All samples were scanned with a 3D scanner, and the geometric sizes of the welded joints were measured using computer software. A modified empirical expression proposed by Ushirokawa and Nakayama was used to calculate the SCF; the expression was adjusted in such a way that the SCF was calculated by knowing only the toe radius. In addition, four new expressions were proposed for the calculation of the SCF by knowing the toe radius ...
Održavanje rafinerijskih postrojenja sa zahtjevima kontinuiranog rada sa sto manjim zastojima i s... more Održavanje rafinerijskih postrojenja sa zahtjevima kontinuiranog rada sa sto manjim zastojima i s ciljem povecanja mehanicke raspoloživosti nije lak zadatak s obzirom na postojeca ogranicenja kao sto resursi, vrijeme, novac, sigurnost, okolis i dr. Remont je planirana periodicka aktivnost održavanja za vrijeme planiranog zastoja u kojem se želi postici maksimalni rezultat planiranih aktivnosti sa svim prisutnim projektnim ogranicenjima. Cilj ovoga rada je identificirati elemente projekta remonta koji ga cine složenim sa svrhom definiranja same uloge, tj. velicine složenosti u planiranju i upravljanju projektom remonta. Prepoznavanje i upravljanje složenim projektima podrazumijeva i sve njegove specificnosti pri pristupu upravljanja, primjerice u odnosu na genericke projekte. U daljnjem istraživanju potrebno je provesti empirijsko testiranje predloženih varijabli te se u ovom radu najavljuje empirijsko istraživanje koje ce se provesti u pet rafinerija nafte lociranih u Hrvatskoj, Ita...
The purpose of this research is to emphasise the significance of management innovation developmen... more The purpose of this research is to emphasise the significance of management innovation development, i.e. its implementation in local government as a prerequisite to facilitate the introduction of other changes and, consequently, development of a higher level of effectiveness. The need to research management innovation in the public sector is gaining in importance due to the ongoing public administration reforms which are often, through the implementation of new methods and management concepts, aimed at increasing public service efficiency and effectiveness. Empirical research was conducted on local government units in Croatia. The research results show the dual relationship between management innovation and effectiveness. In addition to a direct relationship with effectiveness, this paper also confirmed an indirect relationship between implementation of management innovation and effectiveness, through influencing a higher level of implementation of other innovations. This implies th...
Remont rafinerijskih postrojenja nafte (engl. Turnaround Refinery, TAR) je planirani periodicki z... more Remont rafinerijskih postrojenja nafte (engl. Turnaround Refinery, TAR) je planirani periodicki zastoj u kojem se izvrsavaju najznacajnije planirane aktivnosti održavanja. U procesnoj industriji, kao sto su rafinerije nafte, koje su projektirane sa zahtjevima kontinuiranog rada i sa sto vecom mehanickom raspoloživoscu, zastoji moraju biti minimalni i sto je vise moguce planirani. Da bi određeni projekt postigao zadovoljavajacu razinu kvalitete, potrebno je utvrditi utjecajne cimbenike te njihovu međusobnu povezanost. Sustavi upravljanja kvalitetom u poslovnoj primjeni podržani su i provode se pomocu razlicitih modela upravljanja kvalitetom, kao sto su primjerice EFQM, MBNQA i IPMA, na kojima se temelje i brojni drugi primjenjivi modeli. U ovom radu prikazat ce se najznacajniji modeli upravljanja kvalitetom uz osvrt na njihove znacajke potrebne za upravljanje kvalitetom u TAR projektima. TAR projekti jesu projekti s vrlo izraženim posebnostima u aktivnostima održavanja te ce se u rad...
The purpose of our research is to determine quality management approach (its dimensions) in turna... more The purpose of our research is to determine quality management approach (its dimensions) in turnaround projects in oil refineries, and its comparison with the traditional quality management approach in generic projects. The empirical research was conducted on project managers and stakeholders in five oil refineries in Croatia, Italy, Slovakia and Hungary. Data needed for this research were obtained in a survey, in interviews and in official documents.Traditional approach of quality management in generic projects, mostly used in observed refineries, is not fully adequate for turnaround project management in oil refineries. The specificity of the very approach in turnaround projects in oil refineries in relation to generic projects, results in specific approaches to quality management in turnaround projects.
The aim of this study was to determine the success evaluation factors in turnaround projects in o... more The aim of this study was to determine the success evaluation factors in turnaround projects in oil refinery versus performance factors in traditional projects. The specifity of the complex refinery turnaround project management approach in relation to generic projects results in specificity of performance assessment approach. The primary starting point in assessing the success of the project is to define the main objectives and manage within the project limits. It is necessary to define turnaround project success factors in order to have the knowledge in which direction the project strives and that all project participants have common goals from which eventually can be assessed whether the project is successful or not. In further research it is necessary to conduct an empirical testing of the proposed variables and in this paper we announce the empirical research that will be
Surface cracks in butt-welded joints usually occur in places with increased stress concentrations... more Surface cracks in butt-welded joints usually occur in places with increased stress concentrations. The stress concentration factor (SCF) can be calculated using an empirical equation, with five geometric parameters of a butt-welded joint (thickness of the base material, toe radius, weld toe angle, weld width, and reinforcement height). However, in anindustrial environment, it is impractical and sometimes even impossible to measure all five geometric parameters with sufficient accuracy. In this study, eight experiments on butt-welded joints were performed. All samples were scanned with a 3D scanner, and the geometric sizes of the welded joints were measured using computer software. A modified empirical expression proposed by Ushirokawa and Nakayama was used to calculate the SCF; the expression was adjusted in such a way that the SCF was calculated by knowing only the toe radius. In addition, four new expressions were proposed for the calculation of the SCF by knowing the toe radius i...
Implementation of quality management systems within different business operations are supported b... more Implementation of quality management systems within different business operations are supported by several models of quality management, business excellence, etc . The best known models are EFQM, MBNQA and IPMA, on which many other applicable models are based. Most models of quality management are generic and can be applicable to a wide array of business operations. In this paper, models of quality management will be analysed that, based on their characteristics, can be modified and successfully used in refinery turnaround (TAR) projects for the purpose of quality management. TAR projects are projects with very distinctive features and the proposed considerations w ill create the basis for defining the concept of an effective quality management model in projects of that type.
For the purpose of contributing to sustainable machining, the aim was to investigate the turning ... more For the purpose of contributing to sustainable machining, the aim was to investigate the turning of martensitic stainless steel X20Cr13 under alternative cooling and lubrication techniques. The minimum quantity lubrication technique in combination with the vortex tube cooling, as the determined optimal cooling method using the Taguchi-based entropy weighted grey relational analysis (compared to emulsion and minimum quantity lubrication technique) in previous research when turning martensitic stainless steel X20Cr13, were applied in this research in accordance with the Box–Behnken design. The aim is to investigate, when applying the optimal cooling condition (minimum quantity lubrication + vortex) with the Box–Behnken design, which parameters have a significant influence on reducing the surface roughness parameters Ra and Rz and also on the tool life (T). The cutting speed (vc = 260, 290 and 320 m/min), feed rate (f = 0.3, 0.35 and 0.4 mm/rev) and depth of cut (ap = 1, 1.5 and 2 mm) ...
Quality control of welded joint is an indispensable part of the welding production process. As pa... more Quality control of welded joint is an indispensable part of the welding production process. As part of spot resistance welding group, cross-wire welding process showed great application for welding of products for everyday usage. The non-contact quality control checking is fit for purpose due to specific characteristics of welded products that consist of two cross welded wires or a combination of wires and strips. This work proposes a new method for detecting and measuring of required dimensional parameters, but also founds its applicability for other products if required. A crucial parameter of this research is the height of welded joint, which is necessary for calculating the penetration of the wire into the wire. The proposed measuring method with a reconfigurable measuring system is explained in this paper. The main component of this system is using a machine vision system, which has become an indispensable part of industrial metrology and is considered one of the industry 4.0 c...
Provođenje projekta remonta kao najznačajnijeg poduhvata održavanja putem projektnog zadatka izni... more Provođenje projekta remonta kao najznačajnijeg poduhvata održavanja putem projektnog zadatka iznimno je složeno te nerijetko završava neuspjehom. Dostupna literatura u obliku knjiga i znanstveno-stručnih radova temelji se najčešće na osobnim iskustvima autora te na empirijskim podacima bez značajne znanstvene metodološke analize. Takvi podaci su vrlo često subjektivni, značajni kao smjernice u istraživanju, ali znanstveno neutemeljeni. Jedan od razloga nedostupnosti literature o projektima remonta je upravo složenost znanstvenog područja koje objedinjava tematiku upravljanja održavanjem, kvalitetom i projektima. Svrha i ciljevi ovoga rada su definiranje koncepta modela osiguranja kvalitete upravljanja projektima remonta rafinerijskih postrojenja. Definiranje koncepta modela temelji se na šest varijabli međusobno povezanih putem pet hipoteza. Svih pet hipoteza modela testirano je logističkom regresijom. Dobiveni rezultati potvrdili su međuodnos varijabla te su sve hipoteze potvrđene....
Surface cracks in butt-welded joints usually occur in places with increased stress concentrations... more Surface cracks in butt-welded joints usually occur in places with increased stress concentrations. The stress concentration factor (SCF) can be calculated using an empirical equation, with five geometric parameters of a butt-welded joint (thickness of the base material, toe radius, weld toe angle, weld width, and reinforcement height). However, in an industrial environment, it is impractical and sometimes even impossible to measure all five geometric parameters with sufficient accuracy. In this study, eight experiments on butt-welded joints were performed. All samples were scanned with a 3D scanner, and the geometric sizes of the welded joints were measured using computer software. A modified empirical expression proposed by Ushirokawa and Nakayama was used to calculate the SCF; the expression was adjusted in such a way that the SCF was calculated by knowing only the toe radius. In addition, four new expressions were proposed for the calculation of the SCF by knowing the toe radius ...
Održavanje rafinerijskih postrojenja sa zahtjevima kontinuiranog rada sa sto manjim zastojima i s... more Održavanje rafinerijskih postrojenja sa zahtjevima kontinuiranog rada sa sto manjim zastojima i s ciljem povecanja mehanicke raspoloživosti nije lak zadatak s obzirom na postojeca ogranicenja kao sto resursi, vrijeme, novac, sigurnost, okolis i dr. Remont je planirana periodicka aktivnost održavanja za vrijeme planiranog zastoja u kojem se želi postici maksimalni rezultat planiranih aktivnosti sa svim prisutnim projektnim ogranicenjima. Cilj ovoga rada je identificirati elemente projekta remonta koji ga cine složenim sa svrhom definiranja same uloge, tj. velicine složenosti u planiranju i upravljanju projektom remonta. Prepoznavanje i upravljanje složenim projektima podrazumijeva i sve njegove specificnosti pri pristupu upravljanja, primjerice u odnosu na genericke projekte. U daljnjem istraživanju potrebno je provesti empirijsko testiranje predloženih varijabli te se u ovom radu najavljuje empirijsko istraživanje koje ce se provesti u pet rafinerija nafte lociranih u Hrvatskoj, Ita...
The purpose of this research is to emphasise the significance of management innovation developmen... more The purpose of this research is to emphasise the significance of management innovation development, i.e. its implementation in local government as a prerequisite to facilitate the introduction of other changes and, consequently, development of a higher level of effectiveness. The need to research management innovation in the public sector is gaining in importance due to the ongoing public administration reforms which are often, through the implementation of new methods and management concepts, aimed at increasing public service efficiency and effectiveness. Empirical research was conducted on local government units in Croatia. The research results show the dual relationship between management innovation and effectiveness. In addition to a direct relationship with effectiveness, this paper also confirmed an indirect relationship between implementation of management innovation and effectiveness, through influencing a higher level of implementation of other innovations. This implies th...
Remont rafinerijskih postrojenja nafte (engl. Turnaround Refinery, TAR) je planirani periodicki z... more Remont rafinerijskih postrojenja nafte (engl. Turnaround Refinery, TAR) je planirani periodicki zastoj u kojem se izvrsavaju najznacajnije planirane aktivnosti održavanja. U procesnoj industriji, kao sto su rafinerije nafte, koje su projektirane sa zahtjevima kontinuiranog rada i sa sto vecom mehanickom raspoloživoscu, zastoji moraju biti minimalni i sto je vise moguce planirani. Da bi određeni projekt postigao zadovoljavajacu razinu kvalitete, potrebno je utvrditi utjecajne cimbenike te njihovu međusobnu povezanost. Sustavi upravljanja kvalitetom u poslovnoj primjeni podržani su i provode se pomocu razlicitih modela upravljanja kvalitetom, kao sto su primjerice EFQM, MBNQA i IPMA, na kojima se temelje i brojni drugi primjenjivi modeli. U ovom radu prikazat ce se najznacajniji modeli upravljanja kvalitetom uz osvrt na njihove znacajke potrebne za upravljanje kvalitetom u TAR projektima. TAR projekti jesu projekti s vrlo izraženim posebnostima u aktivnostima održavanja te ce se u rad...
The purpose of our research is to determine quality management approach (its dimensions) in turna... more The purpose of our research is to determine quality management approach (its dimensions) in turnaround projects in oil refineries, and its comparison with the traditional quality management approach in generic projects. The empirical research was conducted on project managers and stakeholders in five oil refineries in Croatia, Italy, Slovakia and Hungary. Data needed for this research were obtained in a survey, in interviews and in official documents.Traditional approach of quality management in generic projects, mostly used in observed refineries, is not fully adequate for turnaround project management in oil refineries. The specificity of the very approach in turnaround projects in oil refineries in relation to generic projects, results in specific approaches to quality management in turnaround projects.
The aim of this study was to determine the success evaluation factors in turnaround projects in o... more The aim of this study was to determine the success evaluation factors in turnaround projects in oil refinery versus performance factors in traditional projects. The specifity of the complex refinery turnaround project management approach in relation to generic projects results in specificity of performance assessment approach. The primary starting point in assessing the success of the project is to define the main objectives and manage within the project limits. It is necessary to define turnaround project success factors in order to have the knowledge in which direction the project strives and that all project participants have common goals from which eventually can be assessed whether the project is successful or not. In further research it is necessary to conduct an empirical testing of the proposed variables and in this paper we announce the empirical research that will be
Surface cracks in butt-welded joints usually occur in places with increased stress concentrations... more Surface cracks in butt-welded joints usually occur in places with increased stress concentrations. The stress concentration factor (SCF) can be calculated using an empirical equation, with five geometric parameters of a butt-welded joint (thickness of the base material, toe radius, weld toe angle, weld width, and reinforcement height). However, in anindustrial environment, it is impractical and sometimes even impossible to measure all five geometric parameters with sufficient accuracy. In this study, eight experiments on butt-welded joints were performed. All samples were scanned with a 3D scanner, and the geometric sizes of the welded joints were measured using computer software. A modified empirical expression proposed by Ushirokawa and Nakayama was used to calculate the SCF; the expression was adjusted in such a way that the SCF was calculated by knowing only the toe radius. In addition, four new expressions were proposed for the calculation of the SCF by knowing the toe radius i...
Implementation of quality management systems within different business operations are supported b... more Implementation of quality management systems within different business operations are supported by several models of quality management, business excellence, etc . The best known models are EFQM, MBNQA and IPMA, on which many other applicable models are based. Most models of quality management are generic and can be applicable to a wide array of business operations. In this paper, models of quality management will be analysed that, based on their characteristics, can be modified and successfully used in refinery turnaround (TAR) projects for the purpose of quality management. TAR projects are projects with very distinctive features and the proposed considerations w ill create the basis for defining the concept of an effective quality management model in projects of that type.
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