Razvijene su TiAlN/TiSiN i CrAlN/TiSiN nanoslojne prevlake u kojima je napravljen spoj nanoslojnog i nanokompozitnog dizajna. Akcenat je stavljen na proizvodnju prevlaka visoke tvrdoće i visoke otpornosti na lom. Proučavane su i jednoslojne TiAlN, nanokompozitne TiSiN i višeslojne TiAlN/TiSiN prevlake kako bi se utvrdilo kako dizajn utiče na osobine prevlaka. Sve prevlake pripremane su sa jednim, dva i tri stepena rotacije. Pokazano je da dizajn i vid rotacije značajno utiču na mikrostrukturu i teksturu prevlaka, a time na njihove mehaničke osobine, otpornost na lom, adheziju između prevlake i podloge, topografiju površine i tribološko ponašanje. Nanoslojne i nanokompozitne prevlake odlikuju se kompaktnom nanokristalnom mikrostrukturom, dok jednoslojne TiAlN prevlake imaju stubastu strukturu sa kristalnim zrnima veće veličine. Pri prelasku sa jednog na više stepeni rotacije mikrostruktura prevlaka postaje kompaktnija sa kristalnim zrnima manje veličine i manjom poroznošću. U skladu sa tim, najmanju hrapavost, najveću tvrdoću, najveću otpornost na lom i najveću otpornost na habanje imaju nanoslojne i nanokompozitne prevlake pripremane sa dva i tri stepena rotacije.With the aim to develop hard coatings characterized by both, high hardness and high resistance to cracking, synergy between nanolayered and nanocomposite design was made and nanolayered TiAlN/TiSiN and CrAlN/TiSiN coatings were produced. Monolayer TiAlN, nanocomposite TiSiN and multilayer TiAlN/TiSiN were also studied in order to find the relation between the coating design and their properties. All coatings were deposited with 1-fold, 2-fold and 3-fold rotation. It is shown that coating design and type of rotation have great influence on coating microstructure and texture, and in this way on their mechanical properties, resistance to cracking, adhesion between coating and substrate, surface topography and tribological behavior. Nanolayered and nanocomposite coatings are characterized by compact nanocrystalline microstructure, while monolayer TiAlN coatings have columnar structure with larger crystalline grains. By increasing the number of rotational degrees from 1-fold to 3-fold size of crystalline grains decreases and microstructure becomes more dense. Therefore, nanolayered and nanocomposite coatings deposited with 2-fold and 3-fold rotation are characterized by the highest hardness, highest resistance to cracking, highest wear resistance and the smoothest surface topography

Miletić Aleksandar

Uticaj sredinskog stresa na stabilnost razvića merističkih karakteristika (femoralne pore, subdigitalne lamele, supracilijarne granule) i oblika dorzalne strane glave ispitivan je poređenjem nivoa fluktuirajuće asimetrije (FA) navedenih karakteristika između populacija zidnog guštera (Podarcis muralis) koje naseljavaju urbana i ruralna staništa. Takođe, ispitano je i da li postoje razlike u nivou varijanse simetrične komponente oblika glave, alometriji simetrične komponente oblika i u nivou odstupanja od grupne alometrije između populacija koje naseljavaju ova dva tipa sredina. Pored toga, analizirano je i da li sredinski stres ima uticaja na performansu, kondicioni indeks i prevalencu i intenzitet krvnih parazita kao i da li jedinke koje su zaražene krvnim parazitima i jedinke sa niskim kondicionim indeksom pokazuju viši nivo asimetrije oblika glave. Osnovna hipoteza je bila da će populacije koje naseljavaju suboptimalne uslove životne sredine pokazivati viši nivo FA merističkih karakteristika, viši nivo FA oblika glave, viši nivo varijanse simetrične komponente oblika. Pored toga hipoteza je bila i da će postojati razlike u alometriji simetrične komponente oblika glave, nivou morfološke integracije između dva modula dorzalne strane glave između dva tipa populacija kao i veće odstupanje od grupne alometrije u urbanim populacijama. Takođe, pretpostavka je bila i da će urbane populacije pokazati veću prevalencu i intenzitet krvnih parazita, niži kondicioni indeks ali i da će inficirane jedinke i jedinke sa nižim kondicionim indeksom imati viši nivo FA oblika glave.
U poređenju sa ruralnim populacijama, urbane su pokazale statistički značajno viši nivo FA za sve analizirane merističke karakteristike što ukazuje na to da je stabilnost razvića ovih karakteristika u ovoj sredini narušena. Takođe, uočeno je postojanje razlika u razvojnoj stabilnosti između analiziranih karakteristika što ukazuje na to da razvojna stabilnost može biti specifična za morfološke karakteristike. Nivo fluktuirajuće asimetrije je bio niži kod karakteristika koje su od većeg funkcionalnog značaja, što ukazuje da je kontrola razvića ovih karakteristika bila veća. Pored toga, uočeno je i da postoji značajna korelacija između FA femoralnih pora i subdigitalnih
lamela što ukazuje na to da su ove karakteristike integrisane...Effects of environmental disturbance on developmental stability of meristic traits (femoral pores, subdigital lamelae, supraciliar granules) and dorsal head shape were evaluated by comparing fluctuating asymmetry (FA) levels between populations of the common wall lizard (Podarcis muralis) inhabiting urban and rural areas. Moreover, possible differences in degree of head shape variation, head shape allometry and in deviation from within-group allometric lines were tested between these two population types. Also, it was analysed whether environmental disturbance affects locomotor performance, condition index, and prevalence and intensity of blood parasites but also if infected animals and animals with low body condition show higher degree of head shape asymmetry.
The main hypothesis were that individuals inhabiting suboptimal environments will show higher FA degree of meristic traits and head shape as well as higher degree of head shape variance. Also, it was hypothesised that, due to stressfull conditions, there will be differences in symmetric head shape allometry, differences in the degree of morphological integration between two head modules and differences in the degree of deviation from within-group allometric lines between the two types. Moreover, higher prevalence and intensity of blood parasites and lower body condition were expected in urban populations, as well as higher head shape asymmetry in infected individuals and in individuals with low body condition.
Compared to rural populations, the urban ones showed significantly higher degree of FA for all analysed meristic traits, which suggests that developmental stability of these traits is affected in urban environments. Differences in developmental stability were found between the three traits meaning that developmental stability may be trait specific. Degree of fluctuating asymmetry was lower in functionaly significant traits, suggesting that it may be under stricter developmental control. Significant correlation was found between signed FA of femoral pores and subdigital lamelae,
possibly a sign of morphological integration as these traits develop in the same body part and it is likely that they share same developmental pathways..

Lazić, Marko M.

National Repository of Dissertations in Serbia (NaRDuS)

Fluctuating asymmetry as an indicator of environmental stress in populations of the common wall lizard (Podarcis muralis Laurenti 1768) in urban and rural environments

Design of nanolayered and nanocomposite metal-nitride coatings

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