Vibration Control of an existing building through the Vibrating Barrier

Vibration control of structures is normally addressed through devices such as isolators, dampers and tuned mass dampers. Although those devices are technically sound their use might become unpractical in existing buildings such as heritage structures, whereas the alteration of part of the structure is forbidden for various socio-economic issues. In this context, a novel passive control device called Vibrating Barrier (ViBa) has been recently proposed. The Vibrating Barrier is a massive structure, hosted in the soil and detached from the existing building, calibrated for absorbing portion of the ground motion input energy. The working principle is based on the generally know structure-soil-structure interaction between two vibrating structures and the soil. In this paper the Vibrating Barrier is designed to control the vibration of an existing masonry structure forced by ground motion acceleration. The structure, the soil and the ViBa are assumed to be linear behaving and modelled through a pertinent Finite Element approach. The design is pursued through a simplified discrete model of the structure and the ViBa in which the soil is represented by linear elastic springs. Significant reduction of the dynamic response has been achieved manifesting the potential of the Vibrating Barrier to be a valid alternative whereas the traditional vibration control techniques cannot be applied

Physiological and molecular genetic indicators of interspecific hybridization within the genus Centaurum Hill (Gentianaceae)

Vrste roda Centaurium Hill često hibridizuju u prirodi. Brojni primeri ukazuju na značaj poliploidizacije i hibridizacije tokom specijacije u okviru ovog roda. Ukrštanjem Centaurium erythraea Rafn × C. littorale (Turner) Gilmour u uslovima in vitro, dobijeno je alotetraploidno potomstvo, što ide u prilog hipotezi postojanja nedovoljno efikasnih prereproduktivnih barijera, koje bi sprečavale hibridizaciju. Primenjene metode za detekciju hibridnih jedinki u uslovima in vitro su uspešno iskorišćene i u slučaju prirodnih populacija poreklom sa Subotičko-horgoške peščare. Novi takson, nazvan Centaurium pannonicum, je heksaploid nastao iz ukrštanja C. erythraea × C. littorale ssp. compressum (Hayne) Kischner, nakon fertilizacije, tj. spajanja diploidnog i tetraploidnog jedra. De novo razvijeni EST-SSR markeri ukazuju da C. pannonicum konvergira vrsti C. erythraea, dok je prema fitohemijskim markerima hibridni takson sličniji C. littorale ssp. compressum. Razvijeni setovi EST-SSR i fitohemijskih markera, su transferabilni i na druge vrste roda Centaurium, i mogu značajno doprineti daljim istraživanjima međuvrsne hibridizacije. C. pannonicum stabilno održava svoju heksaploidnu genetičku konstitutciju u prirodnim populacijama, umnogome zahvaljujući samooplodnji i/ili drugim vidovima ukrštanja u srodstvu

Immobilization of enzymes on modified sio2 nanoparticles with organosilanes.

U okviru ove teze, razvijeno je nekoliko procedura za hemijsku modifikaciju površine pirogenih, neporoznih nanočestica silike (FNS) kako bi se na njihovu površinu uvele različite funkcionalne grupe. Prva procedura se sastojala od modifikacije površine nanočestica silike 3-aminopropiltrimetoksisilanom (APTMS-om) radi uvođenja primarnih amino grupa na njihovu površinu...In this thesis, different procedures for fumed nonporous silica nanoparticles (FNS) chemical modification, in terms of introducing different functional groups on the support surface, were developed..

Manganese effects on in vitro development of lesser centaury [Centaurium pulchellum (Sw.) Druce]

To determine the manganese requirement necessary for optimal development of lesser centaury [Centaurium pulchellum (Sw.) Druce] in vitro, we investigated the effect of exogenously applied Mn on different developmental processes such as growth, flowering, fruiting, and seed germination. The application of Mn had no effect on stem length, except at the highest concentration of 10-2 M, which was inhibitory. In addition, C. pulchellum plants were capable of in vitro flowering and fruiting even on media without added Mn. However, Mn content in the media affected seed dimensions, since both length and width of the seeds increased with increasing Mn concentration. Moreover, both excess and absence of Mn in the media caused appearance of necrotic plants. Exogenously applied Mn had no effect on seed germination percentage, except at concentrations greater than 3x10-3 M

Manganese effects on in vitro development of lesser centaury [Centaurium pulchellum (Sw.) Druce]

To determine the manganese requirement necessary for optimal development of lesser centaury [Centaurium pulchellum (Sw.) Druce] in vitro, we investigated the effect of exogenously applied Mn on different developmental processes such as growth, flowering, fruiting, and seed germination. The application of Mn had no effect on stem length, except at the highest concentration of 10-2 M, which was inhibitory. In addition, C. pulchellum plants were capable of in vitro flowering and fruiting even on media without added Mn. However, Mn content in the media affected seed dimensions, since both length and width of the seeds increased with increasing Mn concentration. Moreover, both excess and absence of Mn in the media caused appearance of necrotic plants. Exogenously applied Mn had no effect on seed germination percentage, except at concentrations greater than 3x10-3 M.U ovom radu proučavani su efekti egzogeno apliciranog mangana tokom procesa rasta, cvetanja, plodonošenja i klijanja semena kičice sitne [Centaurium pulchellum (Sw.) Druce], gajene u kulturi in vitro. Rezultati su pokazali da Mn nema efekta na dužinu stabla. Jedino je najviša primenjena koncentracija Mn od 10-2 M imala inhibitorni efekt na posmatrani proces. Biljke kičice sitne mogu ne samo da rastu, već i da cvetaju i plodonose na medijumu bez apliciranog Mn. Međutim, dimenzije semena u mnogome zavise od koncentracije Mn u podlozi. Sa povećanjem koncentracije Mn u podlozi, raste i širina i dužina semena. Izostanak Mn u podlozi, kao i njegove visoke koncentracije uzrokovale su pojavu nekrotičnih biljaka. Koncentracije Mn niže od 3 x 10-3 M nisu imale efekta na procenat proklijalih semena.Projekat ministarstva br. 14303

enzimska lipofilizacija vitamina C linolnom kiselinom - određivanje antioksidativnih i difuzionih svojstava L-askorbil-linolata

Lipophilic derivatives of vitamin C are additives with antioxidant properties, attractive for application in food, cosmetics and pharmaceutics. They could be synthesized in lipase-catalyzed processes by using various acyl donors. Hereby, we present application of linoleic acid, which is polyunsaturated fatty acid essential in human nutrition, for esterification of vitamin C catalyzed by immobilized enzyme preparation Novozym® 435 in acetone. Highest specific ester yield, 9.7 mmol/g of immobilized lipase, was accomplished with 0.15 M of vitamin C, 0.6 M of linoleic acid, 3 g/l of enzyme and 0.07% (v/v) of water, at 60°C. NMR analyses of purified product proved that synthesized molecule was identical to 6-O-ascorbyl linoleate. Capacity of ester for scavenging 2,2-diphenyl-1-picrylhydrazyl radicals was two times higher comparing to parent molecule, vitamin C. Its diffusion coefficient, determined using Franz cell and cellulose acetate membrane, was 40% higher than palmitate and 62% higher than oleate. Obtained results showed that L-ascorbyl linoleate could be successfully synthesized in biocatalyzed processes. Furthermore, it was demonstrated that it possess high potential for application in different lipophilic products due to its liposolubility, high antioxidant efficiency and good diffusion properties.Lipofilni derivati vitamina C su aditivi sa antioksidativnim dejstvom pogodni za primenu u prehrambenim, kozmetičkim i farmaceutskim proizvodima. Mogu biti sintetisani u procesima katalizovanim lipazama korišćenjem različitih acil-donora. U ovom radu, opisana je primena linolne kiseline, polinezasićene masne kiseline esencijalne u ljudskoj ishrani, u esterifikaciji vitamina C katalizovanoj imobilisanim enzimskim preparatom Novozym® 435 u acetonu. Najviši specifični prinos estra od 9,7 mmol/g imobilisane lipaze, ostvaren je sa 0,15 M vitamina C, 0,6 M linolne kiseline, 3 g/l enzima i 0,07 zapr. % vode, na 60°C. NMR analize prečišćenog proizvoda dokazale su da je sintetisani molekul identičan 6-O-askorbil-linolatu. Kapacitet estra za vezivanje 2,2- difenil-1-pikrilhidrazil radikala bio je dva puta viši u odnosu na sam vitamin C. Njegov koeficijent difuzije, određen korišćenjem Franz-ove ćelije i celuloza-acetatne membrane, bio je za 40% viši u odnosu na palmitat i za 62% u odnosu na oleat. Ostvareni rezultati pokazali su da L-askorbil-linolat može uspešno biti sintetisan u biokatalizovanom procesu. Pored toga, dokazano je da ovaj estar poseduje značajan potencijal za primenu u različitim lipofilnim proizvodima zbog svoje liposolubilnosti, snažnog antioksidativnog dejstva i pogodnih difuzionih karakteristika

The New Setup in the Belgrade Low-Level and Cosmic-Ray Laboratory

The Belgrade underground laboratory consists of two interconnected spaces, a ground level laboratory and a shallow underground one, at 25 m.w.e.. The laboratory hosts a low-background gamma spectroscopy system and cosmic-ray muon detectors. With recently adopted digital data acquisition system it is possible to study simultaneously independent operation of two detector systems, as well as processes induced by cosmic-ray muons in germanium spectrometers. Characteristics and potentials of present experimental setup, together with some preliminary results for the flux of fast neutrons and stopped muons are reported.Comment: 12 pages, 16 figure