Fast Fourier Transform IR Characterization of Epoxy GY Systems Crosslinked with Aliphatic and Cycloaliphatic EH Polyamine Adducts

The use of fast FT-IR spectroscopy as a sensitive method to estimate a change of the crosslinking kinetics of epoxy resin with polyamine adducts is described in this study. A new epoxy formulation based on the use of polyamine adducts as the hardeners was analyzed. Crosslinking reactions of the different stoichiometric mixtures of the unmodified GY250 epoxy resin with the aliphatic EH606 and the cycloaliphatic EH637 polyamine adducts were studied using mid FT-IR spectroscopic techniques. As the crosslinking proceeded, the primary amine groups in polyamine adduct are converted to secondary and the tertiary amines. The decrease in the IR band intensity of epoxy groups at about 915 cm(-1), as well as at about 3,056 cm(-1), was observed due to process. Mid IR spectral analysis was used to calculate the content of the epoxy groups as a function of crosslinking time and the crosslinking degree of resin. The amount of all the epoxy species was estimated from IR spectra to changes during the crosslinking kinetics of epichlorhydrin

Pretkoncentracija mikroelemenata iz vode koristeći 4-morfolin ditiokarbamat

The optimum conditions were found for the preconcentration of trace metals in natural waters and model samples with standard metals concentrations by using 4-morpholine dithiocarbamate. The formed complexes were extracted with chloroform. Different methods for recovering the metals from the organic solvent were studied and compared before AAS metal analysis. The developed preconcentration method was successfully applied to the determination of trace metals concentrations in water samples from the "Barje" lake (Leskovac. Yugoslavia).Nađeni su optimalni uslovi za pretkoncentraciju mikroelemenata iz vode koristeći 4-morfolin ditiokarbamat kao kompleksirajući agens. Nagrađeni kompleksi su ekstrahovani hloroformom. Upoređeni su različiti načini ekstrakcije metalnih jona iz organskog rastvarača pre analize atomskom apsorpcionom spektrofotometrijom. Razvijena metoda za pretkoncentraciju uspešno je primenjena za analizu uzoraka vode jezera Barje (Leskovac Jugoslavija)

Koncept sprovođenja komasacije u Republici Srbiji

Land consolidation means a system of spatial planning, technical, legal and socio-economic measures takes by the community for a fundamental improvement of natural, economic and environmental conditions of the land territory with the aim of providing better living and working conditions and environmental protection. This document shows the analyzes of land consolidation development in Republic of Serbia, as well as the facilities and the problems that accompany it. On a practical case for land consolidation area K. O. Priboj, City of Leskovac, an analysis of the situation before land consolidation - the old condition and conditions after land consolidation - a new condition. Explained the phases in the process of land consolidation, and is particularly explained one of the most important stage - the allocation of land consolidation land mass.Uređenje zemljišne teritorije podrazumeva sistem prostorno-planskih, tehničkih, pravnih i ekonomsko-socijalnih mera koje društvena zajednica preduzima za temeljno poboljšanje prirodnih, privrednih i ekoloških uslova zemljišne teritorije s ciljem obezbeđenja kvalitetnijih uslova života i rada i zaštite životne sredine. U radu je analiziran koncept sprovođenja komasacije u Republici Srbiji, kao i pogodnosti i problemi koji prate isti. Na praktičnom primeru za komasaciono područje K.O. Priboj, Grad Leskovac, izvršena je analiza stanja pre komasacije - starog stanja i stanja posle komasacije - novog stanja. Objašnjene su faze u postupku komasacije, a posebno je objašnjena jedna od najbitnijih faza u komasaciji - raspodela zemljišta iz komasacione mase

Physico-chemical characterization of mixed-ligand complexes of Mn(III) based on the acetylacetonate and maleic acid and its hydroxylamine derivative

Two new Mn(III) mixed-ligand complexes with two acetylacetonate (acac) ligands and one maleate ligand and its hydroxylamine derivative of the general formula [Mn(C5H7O2)2L] were prepared. Their structure was established by using elemental analysis, FTIR and UV/VIS spectroscopic methods, as well as magnetic measurement. Replacement of the acetylacetonate ligand by the corresponding acid ligand has been confirmed in Mn(III) acetylacetonate. Based on the obtained experimental data and literature indications, structural formulae to these compounds were assigned

Fauna of monogenean trematodes-parasites of some cyprinid fishes from lake Prespa, Macedonia

During parasitological investigations six species of monogenean trematodes were found on the gills of three cyprinid fish species from Lake Prespa (Macedonia), as follows: Dactylogyrus prostae and Dactylogyrus sphyrna in Leuciscus cephalus albus, Dactylogyrus erhardovae, Dactylogyrus sphyrna and Paradiplozoon zeller in Rutilus rubilio prespensis and Dactylogyrus elegantis and Dactylogyrus vistulae in Chondrostoma nasus prespensis. The prevalence in Leuciscus cephalus albus was 62.22%, in Rutilus rubilio prespensis 59.87% while in Chondrostoma nasus prespensis it was the lowest and amounted to 41.59%. The overall, prevalence of monogeneans in the investigated cyprinid fishes from Lake Prespa was 53.65%, and the mean intensity of infestation was 6.08. Among the monogenean species the highest prevalence occurred with Dactylogyrus sphyrna (25.08%), and the greatest intensity of infestation was evident in the cases of infestation with Dactylogyrus erhardovae (12.87). The greatest pathological effect was associated with the monogeneans Dactylogyrus vistulae and Paradiplozoon zeller. All monogenean species found represented the first record for such parasite fauna of fishes in Macedonia.U toku parazitoloških istraživanja ciprinidnih riba iz Prespanskog jezera (Makedonija), kod 3 vrste riba na škrgama pronađeno je 6 vrsta monogenih trematoda, i to: kod Leuciscus cephalus albus su nađeni Dactylogyrus prostae i Dactylogyrus sphyrna, kod Rutilus rubilio prespensis su pronađeni Dactylogyrus erhardovae, Dactylogyrus sphyrna i Paradiplozoon zeller, kod Chondrostoma nasus prespensis su pronađeni Dactylogyrus elegantis i Dactylogyrus vistulae. Ekstenzitet infestacije kod Leuciscus cephalus albus iznosio je 62,22%, kod Rutilus rubilio prespensis 59,87%, a kod Chondrostoma nasus prespensis je bio najniži i iznosio je 41,59%. Ukupno, ekstenzitet infestacije sa monogeneama kod ispitivanih ciprinidnih riba Prespanskog jezera iznosio je 53,65%, a intenzitet infestacije 6,08. Pojedinačno, po vrstama monogenea, najviši ekstenzitet infestacije je bio sa Dactylogyrus sphyrna (25,08%), a najviši intenzitet infestacije je utvrđen u slučajevima infestacije sa Dactylogyrus erhardovae (12,87). Najveći patogeni uticaj su imale monogene trematode Dactylogyrus vistulae i Paradiplozoon zeller. Sve pronađene vrste monogenea predstavljaju prvi nalaz za parazitofaunu riba Makedonije.nul

Effects of the acrylic polyol structure and the selectivity of the employed catalyst on the performance of two-component aqueous polyurethane coatings

Two kinds of aqueous acrylic polyols (single step and multi step synthesis type) have been investigated for their performance in the two-component aqueous polyurethane application, by using more selective catalysts. The aliphatic polyfunctional isocyanates based on hexamethylen diisocyanates have been employed as suitable hardeners. The complex of zirconium, commercially known as K-KAT(R)XC-6212, and manganese (III) complexes with mixed ligands based on the derivative of maleic acid have been used as catalysts in this study. Both of the aqueous polyols give good results, in terms of application and hardness, when elevated temperatures and more selective catalysts are applied. A more selective catalyst promotes the reaction between the isocyanate and polyol component. This increases the percentage of urethane bonds and the degree of hardness in the films formed from the two components of aqueous polyurethane lacquers. The polyol based on the single step synthesis route is favourable concerning potlife and hardness. The obtained results show that the performance of the two-component aqueous polyurethane coatings depends on the polymer structure of the polyols as well as on the selectivity of the employed catalyst

Discocotyle ohridana n. Sp. (monogenea: Discocotylidae) on the gills of ohrid belvica salmothymus ohridanus (pisces: Salmonidae) from the lake ohrid, macedonia

Discocotyle ohridana n.sp. is described from the gills of Ohrid belvica Salmothymus ohridanus Steindachner, 1892; (syn. Acantholingua ohridana Hadzisce, 1961) from the Lake Ohrid, Macedonia. According our investigation the new species D. ohridana n.sp. differs 56.47% of observed S. ohridanus have been infected and average intensity of infestation is 2.84

Fauna of monogenean trematodes-parasites of some cyprinid fishes from lake Prespa, Macedonia

During parasitological investigations six species of monogenean trematodes were found on the gills of three cyprinid fish species from Lake Prespa (Macedonia), as follows: Dactylogyrus prostae and Dactylogyrus sphyrna in Leuciscus cephalus albus, Dactylogyrus erhardovae, Dactylogyrus sphyrna and Paradiplozoon zeller in Rutilus rubilio prespensis and Dactylogyrus elegantis and Dactylogyrus vistulae in Chondrostoma nasus prespensis. The prevalence in Leuciscus cephalus albus was 62.22%, in Rutilus rubilio prespensis 59.87% while in Chondrostoma nasus prespensis it was the lowest and amounted to 41.59%. The overall, prevalence of monogeneans in the investigated cyprinid fishes from Lake Prespa was 53.65%, and the mean intensity of infestation was 6.08. Among the monogenean species the highest prevalence occurred with Dactylogyrus sphyrna (25.08%), and the greatest intensity of infestation was evident in the cases of infestation with Dactylogyrus erhardovae (12.87). The greatest pathological effect was associated with the monogeneans Dactylogyrus vistulae and Paradiplozoon zeller. All monogenean species found represented the first record for such parasite fauna of fishes in Macedonia.U toku parazitoloških istraživanja ciprinidnih riba iz Prespanskog jezera (Makedonija), kod 3 vrste riba na škrgama pronađeno je 6 vrsta monogenih trematoda, i to: kod Leuciscus cephalus albus su nađeni Dactylogyrus prostae i Dactylogyrus sphyrna, kod Rutilus rubilio prespensis su pronađeni Dactylogyrus erhardovae, Dactylogyrus sphyrna i Paradiplozoon zeller, kod Chondrostoma nasus prespensis su pronađeni Dactylogyrus elegantis i Dactylogyrus vistulae. Ekstenzitet infestacije kod Leuciscus cephalus albus iznosio je 62,22%, kod Rutilus rubilio prespensis 59,87%, a kod Chondrostoma nasus prespensis je bio najniži i iznosio je 41,59%. Ukupno, ekstenzitet infestacije sa monogeneama kod ispitivanih ciprinidnih riba Prespanskog jezera iznosio je 53,65%, a intenzitet infestacije 6,08. Pojedinačno, po vrstama monogenea, najviši ekstenzitet infestacije je bio sa Dactylogyrus sphyrna (25,08%), a najviši intenzitet infestacije je utvrđen u slučajevima infestacije sa Dactylogyrus erhardovae (12,87). Najveći patogeni uticaj su imale monogene trematode Dactylogyrus vistulae i Paradiplozoon zeller. Sve pronađene vrste monogenea predstavljaju prvi nalaz za parazitofaunu riba Makedonije.nul

Procena sadržaja i raspodele teških metala u površinskom sedimentu akumulacije 'Barje' - Srbija

In this study, the nature of the association of heavy metals (Fe, Co, Ni, Cu, Cd, Pb, Mn, and Zn) in sediments of the recent reservoir 'Barje' (Leskovac, Serbia) was investigated. The aim was to make the identification of their substrates, as well as to define the external factors (hydrological and anthropogenic affecting their distribution) which will contribute to a better understanding of the interactions that take place in the reservoir and predict the mobility of the investigated heavy metals. Chemical distribution of heavy metals was tested by using the method of sequential extraction and by data processing using statistical methods such as correlation, cluster and factor analysis. Based on the obtained results it can be concluded that major substrates of heavy metals are in the residual immobile fraction (Fe, Zn and Ni). Since the accumulation has a small organic substance content, Fe and Mn oxides are the most important binding substrates of heavy metals. Although it was determined that lead and cadmium are of the carbonate nature, their concentrations in the reservoir are negligible.Cilj ovog rada je da se ispitivanjem prirode asocijacija teških metala (Fe, Co, Ni, Cu, Cd, Pb, Mn, Zn) izvrši identifikacija njihovih supstrata u akumulaciji 'Barje' (Leskovac, Srbija), kao i da se definišu spoljni faktori (hidrološki i antropogeni koji utiču na njihovu raspodelu) što će doprineti boljem razumevanju interakcija koje se odigravaju u akumulaciji i prognozu mobilnosti na osnovu toga. Hemijska raspodela teških metala ispitana je korišćenjem metode sekvencijalne ekstrakcije i obradom dobijenih podataka statističkim metodama kao što su korelaciona, klaster i faktorska analiza. Na osnovu dobijenih rezultata može se zaključiti da se većina teških metala nalazi u rezidualnoj nepokretnoj frakciji (Fe, Zn i Ni). Zato što je u akumulaciji mali sadržaj organske supstance oksidi gvožđa i mangana su najznačajniji supstrati za vezivanje teških metala. Iako je utvrđeno da je olovo i kadmijum karbonatne prirode njihove koncentracije u akumulaciji su zanemarljivo male