A dark energy view of inflation

Traditionally, inflationary models are analyzed in terms of parameters such as the scalar spectral index ns and the tensor to scalar ratio r, while dark energy models are studied in terms of the equation of state parameter w. Motivated by the fact that both deal with periods of accelerated expansion, we study the evolution of w during inflation, in order to derive observational constraints on its value during an earlier epoch likely dominated by a dynamic form of dark energy. We find that the cosmic microwave background and large-scale structure data is consistent with w_inflation=-1 and provides an upper limit of 1+w <~ 0.02. Nonetheless, an exact de Sitter expansion with a constant w=-1 is disfavored since this would result in ns=1.Comment: 5 pages, 4 figures; v2: minor modifications to match published versio

Use of engineering tools in modelling first bite-case study with grilled pork meat

This study provides an engineering approach in modelling the first bite. Based on the mechanical properties of grilled pork meat obtained by applying compression and Warner Bratzler tests and using the Finite element method, a 3D model of cubic pieces has been created. It was then used for simulating the first bite of pork meat grilled at two temperatures and three positions of the jaws. Stress distribution during impact of upper and lower jaw shows growth of internal stress in the direction of jaw movement, leading to crack development and breaking of meat

Use of engineering tools in modelling first bite-case study with grilled pork meat

This study provides an engineering approach in modelling the first bite. Based on the mechanical properties of grilled pork meat obtained by applying compression and Warner Bratzler tests and using the Finite element method, a 3D model of cubic pieces has been created. It was then used for simulating the first bite of pork meat grilled at two temperatures and three positions of the jaws. Stress distribution during impact of upper and lower jaw shows growth of internal stress in the direction of jaw movement, leading to crack development and breaking of meat

Agricultural production of the Roman provincies in the territory of Serbia : from the 1st to the first half of 5th century

Proučavanja u ovom radu su usmerena na istraživanja različitih elemenata koji se odnose na poljoprivrednu proizvodnju i njen razvoj, kao i promene u njenoj strukturi koje su nastale uspostavljanjem rimske vlasti na teritoriji današnje Srbije u periodu od I do početka V veka. Prema raspoloživim arheološkim podacima, ali i pisanim izvorima, delimično su sagledani uslovi koji su određivali okvire ekonomske aktivnosti stanovništva tokom rimskog perioda i u sklopu toga agrikulture kao fundamentalne delatnosti. Naročita pažnja je posvećena istraživanju tipično rimskih formi poljoprivrednih imanja organizovanim kao vile rustike (villae rusticae) što predstavlja vrlo kompleksan zadatak, budući da uključuje osetljive tipološke i hronološke analize samih građevina kroz arhitektonske forme, koje ponegde uključuju i postojanje žitnica i drugih ekonomskih objekata u sklopu poljoprivrednog imanja. Tokom istraživanja uzimani su u obzir i podaci koje možemo dobiti iz prirodnog okruženja, kao što su: osobine reljefa, pedeološki i hidrološki faktori, klimatske karakteristike itd. Cilj sprovedenog istraživanja bio je da se pruži detaljnije tumačenje arheološke građe koje daje istorijski odgovor na pitanje celokupne poljoprivredne aktivnosti u postavljenim geografskim okvirima sa pokušajem teritorijalne, tipološke i hronološke diferencijacije. Centar pažnje usmeren je na izučavanje forme i organizacije poljoprivrednih imanja, budući da su se zbog različitih socijalno-ekonomskih odnosa, ali i geografskih i klimatskih uslova nužno morale razlikovati od onih u Italiji, ali i drugim provincijama Carstva. Organizacione promene u načinu obrade i kultivisanja zemljišta, uz primenu novog tehnički savršenijeg oruđa od onog korišćenog u predrimskom periodu, novi vidovi uzgoja domaćih životinja, neminovno su uticali na ekonomsko-socijalno raslojavanje stanovništva i proces romanizacije koji je bio intenzivniji u ravničarskim regionima, za razliku od brdsko-planisnkih oblasti gde se usled manje pogodnih prirodnih uslova i izolovanosti prostora uglavnom zadržao tradicionalni način privređivanja. Sagledavši sve prikupljene podatke o proizvodnim jedinicama u poljoprivredi, sredstvima za proizvodnju, transport i distribuciji namirnica, flori i fauni, opšti je zaključak da je stanovništvo panonsko-balkanskog prostora bilo pretežno poljoprivredno u rimskom periodu. KLJUČNE REČI: poljoprivredna proizvodnja, vici, villae rusticae, horrea, snabdevanje i transport, poljoprivredno oruđe, provincije Gornja Mezija, Donja Panonija, istočna Dalmacija, rimski period.The studies in this paper is focused on the investigation of various elements relating to agricultural production and its development, as well as changes in its structure arising establishment of Roman rule in the territory of Serbia in the period from the first to the beginning of the fifth century. According to archaeological evidence, but also written sources, in part conditions were perceived that were determined frames of economic activity of the population during the Roman period and within that agriculture as a fundamental activity. Special attention has been devoted to the study of typical Roman forms of farms organized as villae rusticae which is a very complex task, since it involves sensitive typological and chronological analysis of the buildings themselves through architectural forms, that sometimes involve the existence of granaries and other economic structures in the farm. During the study, it was taken into account data that we get from the natural environment, such as: terrain features, pedological and hydrological factors, climatic characteristics, etc. The aim of the research was to provide a more detailed interpretation of archaeological material that provides historical answer to the question of the entire set of agricultural activities in geographical terms in attempt territorial, chronological and typological differentiation. Center of attention is focused on the study of form and organization of farms, as they are due to various socio-economic relations, but also the geographic and climatic conditions must necessarily differ from those in Italy, but also in other provinces of the Empire. Organizational changes in release and cultivation of land, with the application of a new technically superior tools than that used in the pre-Roman period, new forms of livestock farming, inevitably affected the economic and social stratification of the population and the process of romanization, which was the strongest in the lowland regions, in contrast to highlands areas where due to less favorable natural conditions and isolation of space generally kept the traditional way of economic activity. Analyzed all the data on the production units in agriculture, means of production, transport and distribution of food, flora and fauna, the general conclusion is that the population of the Pannonian-Balkan area was predominantly agricultural in the Roman period

Synthesis, characterization and potential antimicrobial activity of the complexes of some transition metal complexes with edda-type ligands

U prvom delu ove Doktorske disertacije opisana je sinteza i karakterizacija paladijum(II)-kompleksa opšte formule [PdCl2(R2-S,S-eddl)] na bazi infracrvene i elektronske apsorpcione spektroskopije. Izvršeno je in vitro testiranje antimikrobne aktivnosti sintetisanih liganada i odgovarajućih kompleksa protiv 15 vrsta bakterija i gljivica. Takođe, sintetisan je i novi kompleks paladijum(II)-jona sa derivatom kumarina 3-(1-(2-hidroksietilamino)etiliden)hroman-2,4-dionom koji je karak- terisan na bazi mikroanalize, infracrvene i nuklearne magnetne spektroskopije. Predložena struktura kompleksa je potvrđena na osnovu rezultata rentgenske strukturne analize. Sintetisani kompleks je testiran in vitro na ćelijama raka, L929 fibrosarkom miša, U251 ljudski gliom i B16 melanom miša U drugom delu ove Doktorske disertacije opisana je sinteza kompleksa hrom(III)-jona i kobalt(III)-jona. Prvo je opisana sinteza s-cis-[Cr(S,S-eddv)L]-- kompleksa (S,S-eddv = (S,S)-etilendiamin-N,N′-di-2-(3-metil)butanoato jon; L = oksalato ili malonato jon). Kompleksi su prečišćeni jonoizmenjivačkom hromatografijom. Geometrija kompleksa je pretpostavljena na osnovu infracrvenih i elektronskih apsorpcionih spektara, a apsolutne konfiguracije izolovanih kompleksa su pretpostavljene na osnovu njihovih cirkularno-dihroičnih spektara. Takođe, ispitivana je antimikrobna aktivnost sintetisanih kompleksa protiv 28 vrsta mikroorganizama. Sintetisani su i oktaedarski kompleksi kobalta(III) sa (S,S)-etilendiamin- N,N'-di-2-propionskom kiselinom (S,S-eddp) i (S,S)-etilendiamin-N,N'-di-2-(3- metil)buternom kiselinom (S,S-eddv) koji sadrže i okalato i malonato ligande, kao dodatne bidentatne ligande. Kompleksi su prečišćeni jonoizmenjivačkom hromatografijom. Geometrija kompleksa je pretpostavljena na osnovu infracrvenih i elektronskih apsorpcionih spektara, a apsolutne konfiguracije izolovanih kompleksa su pretpostavljene na bazi njihovih cirkularno-dihroičnih spektara koje su potvrđene rezultatima rentgenske strukturne analize u slučaju s-cis-K[Co(S,Seddp)(ox)]·0,5H2O. Takođe, ispitivana je antimikrobna aktivnost sintetisanih kompleksa na 13 vrsta mikroorganizama (pet sojeva patogenih bakterija, pet vrsta patogenih gljiva i tri vrste probiotika).In the first part of the Doctoral thesis the synthesis and characterization of a palladium(II) complexes of general formula [PdCl2 (R2-S,S-eddl)] on the basis of infrared absorption spectroscopy is described. In vitro testing of the antimicrobial activity of the synthesized ligands and the corresponding complexes against 15 species of bacteria and fungi is carried out. Also, a new palladium(II) complex with a coumarine derivative, 3-(1-(2- hydroxyethylamino)ethylidene)chroman-2,4-dione is synthesized and characterized on the basis of microanalysis, the infrared and nuclear magnetic spectroscopy. The proposed structure of the complex was confirmed from the results of X-ray structural analysis. Prepared complex was tested in vitro on cancer cells, L929 mouse fibrosarcoma, human U251 glioma, and mouse melanoma B16. In the second part оf this PhD thesis, the synthesis of chromium(III) and cobalt(III)- complex еs is described. Firstly, the synthesis of s-cis-[Cr(S,S -eddv)L]--complexes (S,S-eddv = (S,S)-ethylenediamine-N,N'-di-2-(3-methyl)butanoate ion, L = oxalato or malonato ion is described. The complexes are purified by ion exchange chromatography. The geometry of the complex is proposed on the basis of infrared and elektronic absorption spectra, and the absolute configuration sof the complexes are predicted based on their circular-dichroiism spectra. Also, the antimicrobial activity of the synthesized complexes against 28 species of microorganisms was investigated. The octahedral cobalt(III) complexes with (S,S)-ethylenediamine-N,N'-di-2-propionic (S,S-eddp) and (S,S)-ethylenediamine-N,N'-di-2-(3-methyl)butanoic (S,S-eddv) acids and oxalato and malonato ligands, as additional bidentate ligands, were prepared and characterized. The complexes were purified by ion-exchange chromatography. The geometry of the complexes has been supposed on the basis of the infrared, electronic absorption and NMR spectra. The absolute configurations of the isolated complexes have been predicted on the basis of their circular dichroism (CD) spectra. Antimicrobial activity of ligand and cobalt(III)-complexes was evaluated in relation to 13 species of microorganisms (five strains of pathogenic bacteria, five species pathogenic fungi and three species of probiotic)

Cluj CJ and PIv Polynomials

A parallel between the counting polynomials CJ(x) and PIv(x), proposed by the groups of Diudea (Romania) and Ashrafi (Iran), respectively, is presented. The both polynomials count the nonequidistant vertices, with respect to any edge in a graph; the difference appeared at the operational stage, as will be demonstrated in this paper. Their first derivatives, in x = 1, provide one and the same value; however, the second derivatives are different. Analytical relations for calculating these polynomials and their single number descriptors, in some classes of graphs are derived

Cluj CJ and PIv Polynomials

A parallel between the counting polynomials CJ(x) and PIv(x), proposed by the groups of Diudea (Romania) and Ashrafi (Iran), respectively, is presented. The both polynomials count the nonequidistant vertices, with respect to any edge in a graph; the difference appeared at the operational stage, as will be demonstrated in this paper. Their first derivatives, in x = 1, provide one and the same value; however, the second derivatives are different. Analytical relations for calculating these polynomials and their single number descriptors, in some classes of graphs are derived

The Use of Acoustoelastic Measurements to Characterize the Stress States in Cracked Solids

The theory of acoustoelasticity predicts that a plane longitudinal acoustic wave passing through a solid which is already in a deformed state will propagate with a velocity (v) which is different from the (v0) of the same wave propagating through the undeformed medium. It may be shown that Δv/v0 = (v-v0)/v0 = B(σ1+σ2) where σ1 and σ2 are the principal stress in the plane normal to the wave propagation direction and B is the acoustoelastic constant. Wave transit time measurements allow the relative velocity change Δv/v0 to be determined, so that contours of constant principal stress sum (σ1+σ2) may be mapped by acoustically scanning a stressed solid. We have used the technique described above to characterize the states of stress in cracked and notched aluminum panels. A method for extracting crack stress intensity factors from the acoustic data is proposed and illustrated for center-cracked panel specimens. The results indicate that the technique may offer a promising method for nondestructive testing and evaluation

Graphene-based waveguide resonators for submillimeter-wave applications

Utilization of graphene covered waveguide inserts to form tunable waveguide resonators is theoretically explained and rigorously investigated by means of full-wave numerical electromagnetic simulations. Instead of using graphene-based switching elements, the concept we propose incorporates graphene sheets as parts of a resonator. Electrostatic tuning of the graphene surface conductivity leads to changes in the electromagnetic field boundary conditions at the resonator edges and surfaces, thus producing an effect similar to varying the electrical length of a resonator. The presented outline of the theoretical background serves to give phenomenological insight into the resonator behavior, but it can also be used to develop customized software tools for design and optimization of graphene-based resonators and filters. Due to the linear dependence of the imaginary part of the graphene surface impedance on frequency, the proposed concept was expected to become effective for frequencies above 100 GHz, which is confirmed by the numerical simulations. A frequency range from 100 GHz up to 1100 GHz, where the rectangular waveguides are used, is considered. Simple, all-graphene-based resonators are analyzed first, to assess the achievable tunability and to check the performance throughout the considered frequency range. Graphene–metal combined waveguide resonators are proposed in order to preserve the excellent quality factors typical for the type of waveguide discontinuities used. Dependence of resonator properties on key design parameters is studied in detail. Dependence of resonator properties throughout the frequency range of interest is studied using eight different waveguide sections appropriate for different frequency intervals. Proposed resonators are aimed at applications in the submillimeter-wave spectral region, serving as the compact tunable components for the design of bandpass filters and other devices