ANALIZA TRŽIŠNIH SUDIONIKA KOJI UPRAVLJAJU POVRATNIM LOGISTIČKIM TOKOVIMA I POSLOVNIM OPERACIJAMA

While segregating the direct and reverse logistics flows, due to the complexity of the returns process management, there have emerged specific market players unique only for these flows. Regarding the organizational aspect, these entities can be formed by the participants of the direct flows, but can also be engaged as specialized external aid. The analyses carried out in practice concerning this topic show that the biggest number of entities involved in managing the reverse logistics processes are within the category of specialized business subjects, which only perform this type of work and which are independent from the actors of regular flows. The subject of this paper is to analyse in depth the volume and importance of reverse logistics flows, focusing on the specifics and types of entities specialized in managing these flows, such as centralized return centres, 3PL and 4PL providers for reverse flows, as well as various business entities of the secondary market. The aim of the paper is to indicate the complexity of tasks performed by specialized entities involved in the reverse logistics process, their scarcity in numbers on a global scale and thus the huge unexploited business potential lying in this market segment. That is a unique chance not only for regional, but also global business milieu.Prilikom razdvajanja izravnih i povratnih logističkih tijekova uslijed složenosti upravljanja povratnim procesom pojavili su se specifični tržišni sudionici koji su svojstveni jedino za ove tijekove. Uzimajući u obzir organizacijski aspekt ovi entiteti mogu biti formirani od strane sudionika izravnih tijekova, ali mogu biti angažirani i kao specijalizirana eksterna ispomoć. Analize provedene u praksi vezane za ovu tematiku pokazuju da je najveći broj sudionika angažiranih u okviru povratnih logističkih procesa u kategoriji specijaliziranih poslovnih subjekata koji samo obavljaju ovu vrstu posla i koju su neovisni od sudionika regularnih tijekova. Predmet razmatranja u radu je dubinska analiza obujma i značaja povratnih logističkih tijekova fokusirajući se na specifičnosti i tipove entiteta koji su specijalizirani za upravljanje ovim tijekovima, kao što su centralizirani centri za povrat, 3PL i 4PL pružatelji usluga za povratne tijekove kao i različiti poslovni subjekti sekundarnog tržišta. Cilj rada je ukazati na kompleksnost zadataka koje provode specijalizirani subjekti angažirani u okviru povratnog logističkog procesa, na njihovu rijetkost na globalnoj razini te stoga i na ogroman neiskorišten poslovni potencijal koji leži u ovome tržišnom segmentu. To je jedinstvena šansa ne samo za regionalno već i za globalno poslovno okruženje

Determination of equilibrium and thermodynamic parameters of the new generation of green solvents toward industrial applications

Industrijski razvoj tokom prošlog veka doprineo je stvaranju problema zagađenja i trošenju fosilnih zaliha prouzrokovanom neefikasnim procesima koji zahtevaju veliki utrošak energije i hemikalija. Održivi procesi u budućnosti trebaju biti orijentisani ka upotrebi manje toksičnih i manje isparljivih supstanci u cilju smanjenja zagađenja vode, vazduha i tla. Rastvarači su osnov svakog industrijskog procesa i predstavljaju jedan od većih izvora zagađenja, s obzirom da su trenutno u upotrebi toksični i isparljivi rastvarači. Stoga je neophodan dizajn alternativnih ekoloških rastvarača i nalaženje njihove primene u postojećim procesima. U ovoj doktorskoj disertaciji ispitivana je potencijalna industrijska primena zelenih rastvarača za tretman toksičnih hemikalija i za separaciju azeotropa. Izvršena je termodinamička i fazna karakterizacija četiri tipa zelenih rastvarača: polimeri, jonske tečnosti, eutektičke smeše i dvofazni vodeni sistemi. Eksperimentalno su određivana termodinamička svojstva čistih komponenata i njihovih smeša u temperaturnom opsegu T = (288.15 K – 333.15 K) i na atmosferskom pritisku. Eksperimentalno su merene gustine , viskoznosti η i indeksi refrakcije nD polimera u smeši sa industrijski važnim jedinjenjima kao što su: aromati, alkoholi i estri. Pomenuti termodinamički parametri su eksperimentalno izmereni i za netoksične smeše polimera sa jonskim tečnostima, smeša rastvarača velikog potencijala za industrijsku primenu. Na isti način okarakterisane su i binarne eutektičke smeše na bazi holin hlorida i jedna ternarna eutektička smeša, sa vodom kao trećom komponentnom, u temperaturnom opsegu T = (298.15 K – 363.15 K). Iz eksperimentalnih podataka izračunate su dopunske molarne zapremine VE, devijacije viskoznosti Δη i devijacije indeksa refrakcije ΔnD koje su fitovane Redlich-Kister polinomom. Izračunate veličine su analizirane u pogledu specifičnih molekulskih interakcija i geometrijskog pakovanja između komponenata smeše, uzimajući u obzir i uticaj temperature. Fourier-ova transformaciona infracrvena (FT-IR) spektroskopija binarnih smeša polimera sa estrima i odgovarajućih čistih komponenata izvedena je na 298.15 K u cilju tumačenja molekulske strukture i mogućih intra- i inter-molekulskih interakcija u rastvorima. Za smeše polietilen glikol diakrilata i alkohola eksperimentalni podaci su korelisani u funkciji od polietilen glikol diakrilat molskog udela i temperature. Indeksi refrakcije binarnih smeša predskazivani su različitim pravilima mešanja (Lorentz-Lorenz, Dale-Gladstone, Eykman, Arago-Biot, Newton i Oster) i rezultati su upoređivani sa eksperimentalnim podacima. Viskoznost je modelovana pomoću dva tipa modela: modeli doprinosa grupa UNIFAC-VISCO i ASOG-VISCO i korelativni Teja-Rice i McAllister modeli. Eksperimentalne vrednosti viskoznosti su korišćene u određivanju novih interakcionih parametara različitih funkcionalnih grupa zarad njihove primene u UNIFAC-VISCO i ASOG-VISCO modelima. Dopunska molarna zapremina je modelovana Peng-Robinson-Stryjek-Vera kubnom jednačinom stanja (PRSV CEOS) primenom van der Waals jedan fluid i TCBT pravila mešanja...Industrial development during the last century has contibuted to pollution problem and depletion of fossil stocks due to unefficient processes which require more energy and chemicals. Sustainable processes in the future have to be oriented to less toxic and less volatile substances in order to reduce air, water and ground pollution. Solvents are basis for each industrial process and represent huge pollution source since toxic and volatile ones are in use currently. Therefore design of alternative ecological solvents and finding their application in exsisting processes is necessary. This thesis is dealing with potential industrial application of green solvents for treatment of toxic chemicals and azeotrope breaking. Thermodynamic properties of pure components and their mixtures were experimentally determined in wide temperature range T = (288.15 K – 333.15 K) and at atmospheric pressure. Densities , viscosities η and refractive indices nD were experimentally measured for polymers in the mixture with industrially important compounds like: aromatics, alcohols, esters. Same thermodynamic parameters were also experimentally determined also for non-toxic mixtures of polymers and ionic liquids, solvent mixtures of huge potential for industrial application. Choline chloride based binary eutectic mixtures and one ternary mixture with water as a third component were characterized in the same way in temperature range T = (298.15 K – 363.15 K). From experimental data excess molar volumes VE, viscosity deviations Δη and deviations in refractive index ΔnD were calculated and fitted with Redlich-Kister polinomial equation. Calculated properties were analyzed in terms of specific molecular interactions and geometrical effects between mixture’s components, taking into account temperature influence. Fourier transform infrared (FT-IR) spektroscopy of polymer + esters binary mixtures and corresponding pure components was performed at 298.15 K for the purpose of interpretation of molecular structure and possible intra- and inter-molecular interactions in solutions. For polyethylene glycol diacrylate + alcohol mixtures experimental data were correlated versus polyethylene glycol diacrylate mole fraction and temperature. Refractive indices of binary mixtures were predicted with various mixing rules (Lorentz-Lorenz, Dale-Gladstone, Eykman, Arago-Biot, Newton and Oster) and the results were compared with experimental data. Viscosity modeling was performed by two types of models: group contribution models UNIFAC-VISCO and ASOG-VISCO and correlative Teja-Rice and McAllister models. Experimental viscosity values were used for determination of new binary interaction parameters of various functional groups in order to be used in UNIFAC-VISCO and ASOG-VISCO models. Excess molar volume was modeled using Peng-Robinson-Stryjek-Vera cubic equation of state (PRSV CEOS) applying van der Waals one fluid and TCBT mixing rules..

ODREĐIVANJE ČIMBENIKA I MODELIRANJE LOGISTIKE POVRATA: TEORIJA VS. PRAKSA

Reverse logistics management has been the subject of scientific and practical attention for a few decades now. An additional interest for this topic has arisen during the last decade, due to a growing number of business entities it affects and the insight into the strategic potential of adequately managing the reverse logistics flows. Up to now, practical research and empirical confirmation regarding reverse logistics management has been scarce, and the question of defining elements, i.e. factors which determine the reverse logistics flows has remained without a complete answer. In time, various authors have tried to solve this question by setting certain guidelines and models which comprehensively show factors considered to be of key importance for the realization of the reverse logistics flows. The subject of this paper is to analyze in depth such existing models. After defining the very term of reverse logistics, the carried out model analysis respects the dynamic time component, first focusing on the theoretical model in this area- the Carter-Ellram model, and later on to the one empirically confirmed- the contemporary reverse logistics model. The aim of this paper is threefold. First, to explain the evolution of the meaning of reverse logistics. Second, to revise the two approaches which most comprehensively define the set of factors considered to be of most importance for the reverse logistics management. Thirdly, it is necessary to compare the factors identified within the theoretical model, with the ones generated empirically, in order to see the similarities and certain differences among them.Upravljanje logistikom povrata predmet je pozornosti znanstvenika i praktičara već nekoliko desetljeća unatrag. Povećani interes za ovu temu javio se posljednjeg desetljeća uslijed sve većeg broja poslovnih subjekata na koje ona utječe, kao i uvida u strateški potencijal adekvatnog upravljanja tijekovima logistike povrata. Do sada, praktična istraživanja i empirijska potvrda u pogledu upravljanja logistikom povrata bili su rijetki, a pitanje definiranja elemenata tj. čimbenika tijekova logistike povrata ostalo je bez potpunog odgovora. Protekom vremena različiti autori pokušali su riješiti ovo pitanje postavljajući određene smjernice i modele koji sveobuhvatno ukazuju na čimbenike za koje se vjeruje da su od ključne važnosti za realizaciju tijekova logistike povrata. Predmet ovog rada jest dubinska analiza takvih postojećih modela. Nakon definiranja samog pojma logistike povrata, provedena analiza modela uvažava dinamičku vremensku komponentu, prvo se usredotočujući na teorijski model u području - Carter-Ellram model, a zatim na onaj empirijski potvrđen - suvremeni model logistike povrata. Cilj ovog rada je trostruk. Prvo, objasniti evoluciju u značenju logistike povrata. Drugo, revidirati dva pristupa koja na najcjelovitiji način identificiraju čimbenike koji se smatraju od najveće važnosti za upravljanje logistikom povrata. Treće, usporediti čimbenike prvog, teorijskog modela, s onima koji su dobiveni empirijski, kako bi se vidjele sličnosti i razlike između njih

Application of FeAl-LDH@SiO2 for Phosphate Removal from Water

In present study FEAL-LDH@SIO2 were Used for removing phosphate from aqueous solutions. FeAl-LDH with molar ratio Fe/Al = 3/1 was synthesized by co- precipitation from aqueous solutions in the present of SIO2 PARTICLES. Silica obtained from rice husks were used as a substrate for the deposition of LDH particles. The prepared material was characterized by scanning electron microscope (FE-SEM), X-ray diffraction (XRD), N2 adsorption/desorption isotherms (BET method) and Fourier transform infrared spectroscopy (FTIR). XRD analysis showed that Fe-Al had formed LDH structure. SEM analysis revealed deposition of LDH particles on SIO2 SUBSTRATE. The adsorption characteristics for phosphate uptake of the obtained material were performed. Adsorption experiments were carried out as a function of LDHs dosage with three different mass ratios of LDH/silica = 1/1, 2/1, and 3/1 and different phosphate concentration AT INITIAL PH 4. Phosphate concentrations were determined using spectrophotometer. The results showed that the maximum sorption capacities of phosphates calculated based on Langmuir equation was 52.68 mg g-1.The book of abstract available at: [http://conf.univerzitetpim.com/wp-content/uploads/2022/06/Book-of-Abstracts_2022-1.pdf

Acrylic Dental Composites for Dentures and Adhesives Mechanical Propreties Modified Using Alumina, Silica and Composite LDH@silica Particles

An overview of advanced composite materials based on thermoplastic polymers for use in dentistry as basic materials for dentures and other industrial applications has been made. These advanced composite materials are reinforced using various oxide fillers. Alumina based particles were prepared from aluminium chloride hydroxide as starting material by sol-gel technique. One series of particles was doped with ferrous oxide. Both series of particles were calcinated at three different temperatures: 700 °C, 800 °C and 900 °C. It was investigated whether and how the calcination temperature of particles affects the microhardness and mechanical properties of composites. Another type of filler used were silica particles obtained from rice husk, as well as silica particles to which, double hydroxide particles were deposited as surface modifiers. The prepared particles were used in amounts of 1, 3 and 5 wt. % as reinforcing agents. Characterization of the synthesized particles was performed by X-ray diffraction, Fourier transforms infrared spectroscopy (FTIR) and scanning electron microscopy with EDS. The development and synthesis of two acrylate matrices are presented. One of the matrices used is polymethylmethacrylate (PMMA) which has been thermally polymerized and used for denture materials. The mechanical properties of PMMA composites, such as hardness, impact resistance, tensile test and toughness of the material, were investigated. Photopolymerizable acrylates such as Bis-GMA (bisphenol A glycidyl methacrylate)/TEGDMA (triethylene glycol dimethacrylate) were used for the second type of matrix. This matrix was used to test the adhesion between a composite film with given particles as reinforcements on a metal surface. Three different methods were used to test adhesion: determination of film hardness and quantitative assessment of bond strength according to Chen Gao model; wetting angle between composite and substrate determination; and cavitation testing. The mechanical properties of composite materials are improved by increasing the reinforcement content. It is proved that the adhesion is improved with addition of the fillers

Mechanical Properties of Composite Material Reinforced With Silica Particles Obtained from Biomass Modified With Double-Layered Hydroxides

Silica particles were produced form rice husk and used as reinforcement in the polymer matrix. The obtained silica particles' surfaces were modified with layered double hydroxides, which enabled better reinforcement in the PMMA matrix. Coprecipitation was used to synthetize Fe Al layered double hydroxides (LDH) with a Fe:Al cation content of 3:1 and an FeAl-LDH: silica ratio of 1:1. X-ray diffraction, Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy with EDS were used to characterize the synthesized particles. The prepared particle amounts in the PMMA matrix were 1, 3, and 5 wt. %. The purpose of this study was to see if the obtained SiO2 particles, as well as their modification with FeAl-LDH, had any effect on the mechanical properties of polymer composite materials. The mechanical characterization of obtained composites was done using Vickers microindentation tests and impact testing. The Vickers micro-hardness test showed that the addition of reinforcement increases the hardness of the composite. When compared to the matrix, the toughness of the composite material with a higher content of particles (5 wt. %) in the energy absorbed in this impact test was three times higher.The book of abstract available at: [http://conf.univerzitetpim.com/wp-content/uploads/2022/06/Book-of-Abstracts_2022-1.pdf

Environmental and Community Stability of a Mountain Destination: An Analysis of Residents’ Perception

This study aims to explore the use of the social-ecological system (SES) in tourism of a mountain area. Authors examined residents’ perceptions of tourism impacts on four SES aspects: ecosystems, local knowledge, people and technology and property rights institutions. The aim is to find area that will be a “common ground” for community and area that can be a source of conflict and will require additional work to solve the differences. Second objective was to examine residents’ perception towards future local development tourism policies (winter tourism, seasonality and environment and culture) and how those policies can affect natural, socio-economic and cultural aspects of mountain area. Residents’ perceptions of sustainable tourism development potential, perceivedtourismimpacts,analysisofcommunityattachmentandemploymentsectorofstakeholder were involved in this study. The authors applied the Q-methodology, as one SES-allied approach, in a small mountain community of Kopaonik, the Republic of Serbia. The results revealed that residents’ agreement/disagreement is connected with two aspects: ecosystem and property rights andthatecosystemcanbesignificantlyinfluencedbyallthreedevelopmentpolicies. Findingssuggest that development of future natural conservation plans and new cultural attractions can have positive effects on all parts of social-ecological system. Some practical implications of those findings for tourism planning and development are also discussed

A gold nanoparticles and hydroxylated fullerene water complex as a new product for cosmetics

Three types of gold nanoparticles (AuNPs) were synthesised with a custom-made Ultrasonic Spray Pyrolysis (USP) device, from aqueous solutions of gold (III) chloride (AuCl3) and gold (III) acetate (AuC6H12O6), with an initial concentration of Au 0.5 g/L. AuNPs were collected in suspensions of deionised (D.I.) water with the stabilisers polyvinylpyrrolidone (PVP) or polyethylene glycol (PEG), followed by the process of freeze drying the AuNPs to be useful as a new additive for the cream. The standard cream base was used as a matrix for preparation of three types of cream with AuNPs in the same concentration ratios. The third AuNPs cream was prepared with a patented hydroxylated fullerene water complex (3HFWC-W) matrix. To examine the effect of AuNPs as additive in creams, a six-week study of test creams was conducted on 33 volunteers with no dermatological diseases. During the study three main parameters of the skin where measured: Collagen quality, skin moisturisation and the epidermis-dermis function. The results of the study found improvements of collagen quality between 18-24 %, achieved due to the use of AuNPs in standard creams, while the cream with the combination of 3HFWC-W and AuNPs gave significantly higher improvements with a value of 45.7 %. It was also discovered that hydration of the skin (stratum cornum) increased by 6.4-9.6 % in standard creams with AuNPs, and 73.7 % in the 3HFWC/AuNPs' cream. Similar results were measured by the epidermisdermis function, where 24-28 % improvement for standard creams with AuNPs was identified, and 38.4 % for the cream 3HFWC-W/AuNPs