Analysis of forensic samples of "Ecstasy" tablets seized in Novi Sad during the 2004 year

The paper presents results of the analysis of illicit synthetic drugs in the form of tablets distributed under the name "Ecstasy", seized by the police in the broader area of Novi Sad 2004. A huge number of tablets has been analyzed (n=121), of various colours and with impressed symbols from the total amount of 93 seizures, which totally amounted to 1458 tablets. Regarding the number of seizures ecstasy (3,4-methylendioxy-N-meth-yl-amphetamine - MDMA) is dominant among all, and according to the quantity of seized tablets it is amphetamine (AP), while other amphetamine-type drugs (methamphetamine MA 3,4-methylendioxiamphetamine - MDA, 3,4-methylendioxi-N-ethyl-amphetamine MDEA) have been found in rather small quantities and very rarely. Tablets mostly contain caffeine as an additive. In the analytical procedure, the samples of tablets were subjected to liquid-liquid extraction and afterwards analyzed on the GCD (GC-EI) Hewlett-Packard instrument. The method is fast reliable and reproducible for the analysis of amphetamine, methamphetamine MDA, MDMA, MDEA, as well as various additives in the samples of seized tablets

Remaining life assessment of a high pressure turbine casing in creep and low cycle service regime

Thick walled components such as high pressure (HP) steam turbine casings operating under high parameter conditions are subjected to a complex stress state. As a result of that stress state, some parts of HP turbine casing undergo to the creep fatigue caused by the combination of thermal fatigue resulted from repeated start/stop operation and the creep which occurs during long-term operation at high temperature and high-pressure. It is well known that domestic thermal power plants have been in use over 100000 h which means that significant cost is required not only for maintenance, but often for renewal of equipment. Based on comprehensive investigation, the results of residual life assessment of one high pressure steam turbine casing, which belongs to the older turbine generation, taking into account simultaneous action of thermal fatigue and creep, are presented in this paper. Also, the critical flaw crack size of HP turbine casing is determined because this parameter has a strong influence on casing integrity and residual life. The results of residual life assessment provide not only a basis for further maintenance, but also estimated time for reparation or renewal

Remaining life assessment of a high pressure turbine casing in creep and low cycle service regime

Thick walled components such as high pressure (HP) steam turbine casings operating under high parameter conditions are subjected to a complex stress state. As a result of that stress state, some parts of HP turbine casing undergo to the creep fatigue caused by the combination of thermal fatigue resulted from repeated start/stop operation and the creep which occurs during long-term operation at high temperature and high-pressure. It is well known that domestic thermal power plants have been in use over 100000 h which means that significant cost is required not only for maintenance, but often for renewal of equipment. Based on comprehensive investigation, the results of residual life assessment of one high pressure steam turbine casing, which belongs to the older turbine generation, taking into account simultaneous action of thermal fatigue and creep, are presented in this paper. Also, the critical flaw crack size of HP turbine casing is determined because this parameter has a strong influence on casing integrity and residual life. The results of residual life assessment provide not only a basis for further maintenance, but also estimated time for reparation or renewal

Determination of the BTEX compounds in building materials and waste samples containing mineral oils as the main component using Headspace GC/FID

BTEX jedinjenja su lako isparlјiva aromatična jedinjenja, klasifikovana kao toksična jedinjenja i kao takva su opasna po zdravlje ljudii životnu sredinu. Predmet istraživanja u ovom radu su BTEX jedinjenja u uzorcima građevinskog materijala sa mineralnim uljima kao glavnom komponentom. S obzirom da su ona sastavni deo mineralnih ulja, važno je odrediti njihovo prisustvo, koncentraciju i dalju distribuciju u životnu sredinu. Tokom eksperimentalnog istraživanja, ispitivan je sadržaj BTEX jedinjenja: benzen, toluen, ksilen (o, p, m) i etilbenzen u uzorcima mineralnih ulja iz građevinskih materijala i otpada. Metoda za određivanje ovih jedinjenja, kao i za njihovu kvantifikaciju u uzorcima mineralnih ulja, razvijena je u Laboratoriji za fizičku hemiju, Instituta za nuklearne nauke „Vinča“, Univerziteta u Beogradu, modifikacijom i unapređenjem standardnih metoda[1, 2]. Za potrebe ovog istraživanja,u eksperimentalnom delu, primenom Headspace ekstrakcije sa GC-FID tehnikom, određen je kvalitativni i kvantitativni sadržaj BTEX jedinjenja, što istovremeno predstavlja i validaciju ispitivane metode, kao i određivanje njene merne nesigurnosti (Tabela 1.).Parametri za validaciju ove metode su bili: specifičnost, linearnost, granica detekcije (LOD), granica kvantifikacije (LOQ), ponovljivost i tačnost svakog jedinjenja. Primenom opisane metode postignuta je pouzdana identifikacija ispitivanih jedinjenja. Identifikacija se ostvaruje poređenjem retencionih vremena ispitivanih jedinjenja sa retencionim vremenima analitičkih standarda. FID detektor pokazuje linearan odgovor u opsegu 0,1 do 10 µg , odnosno R ≥ 0,99. Vrednosti standarda na kalibracionoj krivi su potvrdili preciznost metode. Relativna standardna devijacija RSD je ispod 5%, što dokazuje da je metoda tačna i reproduktivna [3-8]. Predstavljena metoda je validirana kao pouzdana, precizna i tačna za potrebe kontrole kvaliteta mineralnih ulja koja su korišćena ili će se koristiti u toku izgradnje građevinskih objekata, kao i za otpadni materijal.8th Symposium Chemistry and Environmental Protection : May 30 - June 1, Kruševac, 2018

Analysis of the properties of a Cu-Al2-O3 sintered system based on ultra fine and nanocomposite powders

In this paper synthesis of a composite based on Cu-Al2O3 by a thermo-chemical method is shown along with a comparative analysis of the properties of the obtained nanocomposite sintered samples, which are characterized by a good combination of electric-mechanical properties, suitable for work at elevated temperatures. Ultra fine and nanocrystal powder Cu-Al2O3 is obtained by a chemical method, starting from water solutions of nitrates up to achieving the requested composition with 3 and 5% of Al2O3. Synthesis of composite powders has been developed through several stages: drying by spraying, oxidation of the obtained powder of precursor and then reduction by hydrogen until the final composition of nanocomposite powder is achieved. After characterization of the obtained powders, which comprised examination by the Scanning Electronic Microscopy (SEM) method and X-ray-structure analysis (RDA), the powders were compacted with compacting pressure of 500 MPa. Sintering of the obtained samples was performed in the hydrogen atmosphere in isothermal conditions at temperatures of 800 and 900oC for 30, 60, 90 and 120 minutes. Characterization of the obtained Cu-Al2O3 of the nanocomposite sintered system comprised examination of microstructure by the Scanning Electronic Microscopy (SEM), as well as examining of electric mechanical properties. The obtained results show a homogenous distribution of dispersoides in the structure, as well as good mechanical and electric properties. .U radu je prikazana sinteza kompozita na bazi Cu-Al2O3 termohemijskim putem uz uporednu analizu svojstava dobijenih nanokompozitnih sinterovanih uzoraka, koje karakteriše dobra kombinacija električna-mehanička svojstva, pogodnih za rad na povišenim temperaturama. Ultra fini i nanokristalni prah Cu-Al2O3 dobijen je hemijskim putem polazeći od vodenih rastvora nitrata do postizanja zahtevanog sastava sa 3 i 5% Al2O3. Sinteza kompozitnih prahova se odvijala kroz nekoliko faza: sušenje raspršivanjem, oksidacija dobijenog praha prekursora i zatim redukcija vodonikom do postizanje konačnog sastava nanokompozitnog praha.Nakon karakterizacije dobijenih prahova, koja je obuhvatila ispitivanja metodom skanirajuće elektronske mikroskopije (SEM) i rendgenostrukturne analize (RDA), vršeno je presovanje prahova pritiskom presovanja od 500 MPa. Sinterovanje dobijenih uzoraka vršeno je u atmosferi vodonika u izotermskim uslovima na temperaturama 800 i 900o C u toku 30, 60, 90 i 120 minuta. Karakterizacija dobijenog Cu-Al2O3 nanokompozitnog sinterovanog sistema je obuhvatila ispitivanja mikrostrukture skanirajućom elektronskom mikroskopijom, kao i ispitivanja električnih i mehaničkih svojstava. Dobijeni rezultati pokazuju homogenu raspodelu disperzoida u strukturi, kao i dobre mehaničke i električne osobine.

Synthesis of substituted allyl acetates from heterocyclic dienes by Pd-promoted arylation-acetoxylation cascade

Pd-catalysed arylation–acetoxylation cascade, a previously reported methodology, was applied in the functionalisation of unsymmetrical dienes. Both explored classes of compounds, isoquinoline and β-carboline-derived dienes, afforded single regioisomers. Although further improvements of the process are necessary, primarily due to lower yields, the described functionalisation of the studied compounds might be useful in the synthesis of emetine and related naturally occurring compounds. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 172009

Remaining life assessment of a high pressure turbine casing in creep and low cycle service regime

Thick walled components such as high pressure (HP) steam turbine casings operating under high parameter conditions are subjected to a complex stress state. As a result of that stress state, some parts of HP turbine casing undergo to the creep fatigue caused by the combination of thermal fatigue resulted from repeated start/stop operation and the creep which occurs during long-term operation at high temperature and high-pressure. It is well known that domestic thermal power plants have been in use over 100000 h which means that significant cost is required not only for maintenance, but often for renewal of equipment. Based on comprehensive investigation, the results of residual life assessment of one high pressure steam turbine casing, which belongs to the older turbine generation, taking into account simultaneous action of thermal fatigue and creep, are presented in this paper. Also, the critical flaw crack size of HP turbine casing is determined because this parameter has a strong influence on casing integrity and residual life. The results of residual life assessment provide not only a basis for further maintenance, but also estimated time for reparation or renewal

Novel photochemical advanced oxidation process for the removal of polycyclic aromatic hydrocarbons from polluted concrete

Polycyclic aromatic hydrocarbons (PAHs) are denoted by International Agency for Research on Cancer as mutagens, teratogens and carcinogenic to humans. In 2013, Vinca Institute of Nuclear Sciences was hired to determine whether PAHs are present in significant quantities in the concrete walls of newly built residential buildings (about 15,000 m(2) of apartments), and to propose appropriate technical solution for PAH removal in this case. As PAH occurrence, determination and remediation in concrete is, to our knowledge, a completely new field, it was necessary to face a number of challenges, including lack of regulations considering contents of PAHs in concrete, investigation of the origin of PAH contamination in concrete (if established), as Well as finding feasible and non-expensive remediation method, which would be appropriate for residential space. In first part of this study, a Markedly high concentrations of 5 PAHs were detected by UPLC/PDA analysis in samples of both concrete walls and mineral oil used for coating of planks during formwork, while control concrete and mineral oil, taken from independent construction site, were taken as a reference. Such coincidence, as well as the fact that mineral oil has penetrated into the concrete which is proven by ASAP/MS analysis, pointed to the mineral oil as the most probable source of PAH contamination of the concrete. In the second part, an efficient and easy-applicable method for PAH oxidation in concrete (called FHO3AOP), using UV light, H2O2 and ozone, was presented and discussed in terms of previous literature data. (C) 2016 Elsevier B.V. All rights reserved