66 research outputs found
Assessment of the environmental situation of Albanian rivers based on physico-chemical analyses
EnWater quality parameters and heavy metal levels were monitored during 2002 –2004 on eight campaigns along the most impacted rivers of the Albanian Adriatic lowlands:the Mati with its tributary Fani,Ishmi with its tributaries Lana and Tirana,the Shkumbini,and the Semani with its tributaries Gjanica and Osumi (Fig.1).Water samples were analysed for general physico-chemical parameters,concentrations of nutrients,and levels of heavy metals (Pb,Cd,Cu,Zn,Fe,Mn,Cr,Ni,Hg).Several sediments and biota (algae)samples were analysed for heavy metals,too. Assessment of environmental quality of waters is based on two “quality standards ”:the classification of the Norwegian Institute for Water Research (NIVA 1997)[4 ]and the European Community Directive (EEC/EEAC/EC 78/659)on “Quality of fresh waters supporting fish life ”[5 ].Obtained data have been reported recently [1,2,3 ].The most critical chemical parameters for nearly all studied rivers found:(a)Total suspended solids (TSS)in excess of 25 mg/L in many sampling points,due to the intensive erosion of the land;(b)High nutrient concentrations in rivers near big towns.Very low dissolved oxygen (eutrophication)was found in the river Ishmi near Tirana city and the river Semani near Fieri city, caused by the discharges of untreated sewage waste-waters.The most polluted rivers for nearly all parameters were the Lana (tributary of the Ishmi)and the Gjanica (tributary of Semani).The conclusions from the chemical analyses are very similar to those found in a parallel study of biological parameters for diatoms in the framework of this study. Systematic monitoring programs are urgently needed to understand the present environmental state of Albanian rivers and other aquatic ecosystems to characterize the main sources of pollution and to lay the basis for political guidelines to improve the ecological situation
Biochemical normalization of trace metals in Arctocephalus australis
Arctocephalus australis foi usado como organismo indicador para concentrações de metal traço na costa do Rio Grande do Sul. Metais foram analisados em tecidos extraídos do coração, rins e fígado. Os baixos teores encontrados no coração inicialmente poderiam indicar que este órgão não traria resultados relevantes. Porém, mediante a aplicação de um procedimento de normalização, foram encontrados coeficientes de pré-concentração de 43.1 e de 8.6 para o coração e para os rins, respectivamente, indicando o tecido do coração como o melhor bioindicador para Hg. Para Cd, os coeficientes de pré-concentração foram 128.1, 195.3 e 5.2 para fígado, rins e coração, respectivamente, demonstrando alta capacidade acumulativa especialmente para fígado e rins. Foram encontradas altas correlações positivas entre o Fe e os metais Zn, Cu, Cd, Hg, Ag, Mn, Ni, Cr e Pb, indicando ser este elemento normalizante para definição da concentração bioquímica natural de metais na população de Arctocephalus australis no extremo sul do Brasil.Initially, the heart concentration data does not seem relevant for use as a bioindicator, mainly due to its low concentration level. After applying a normalizing procedure, the heart results were a better Hg bioindicator (preconcentration coefficient 43.1) than those of the kidney (preconcentration coefficient 8.6). Cadmium preconcentration coefficients were 128.1, 195.3 and 5.2 for liver, kidney and heart, respectively, demonstrating the high accumulative capacity especially for the liver and kidneys. Iron is proposed as a normalizing element for the definiton of the regional natural biochemical population of the metals. In general, positive correlation coefficients were found between Fe and other metals
Assessment of the environmental situation of Albanian rivers based on physico-chemical analyses
EnWater quality parameters and heavy metal levels were monitored during 2002 –2004 on eight campaigns along the most impacted rivers of the Albanian Adriatic lowlands:the Mati with its tributary Fani,Ishmi with its tributaries Lana and Tirana,the Shkumbini,and the Semani with its tributaries Gjanica and Osumi (Fig.1).Water samples were analysed for general physico-chemical parameters,concentrations of nutrients,and levels of heavy metals (Pb,Cd,Cu,Zn,Fe,Mn,Cr,Ni,Hg).Several sediments and biota (algae)samples were analysed for heavy metals,too. Assessment of environmental quality of waters is based on two “quality standards ”:the classification of the Norwegian Institute for Water Research (NIVA 1997)[4 ]and the European Community Directive (EEC/EEAC/EC 78/659)on “Quality of fresh waters supporting fish life ”[5 ].Obtained data have been reported recently [1,2,3 ].The most critical chemical parameters for nearly all studied rivers found:(a)Total suspended solids (TSS)in excess of 25 mg/L in many sampling points,due to the intensive erosion of the land;(b)High nutrient concentrations in rivers near big towns.Very low dissolved oxygen (eutrophication)was found in the river Ishmi near Tirana city and the river Semani near Fieri city, caused by the discharges of untreated sewage waste-waters.The most polluted rivers for nearly all parameters were the Lana (tributary of the Ishmi)and the Gjanica (tributary of Semani).The conclusions from the chemical analyses are very similar to those found in a parallel study of biological parameters for diatoms in the framework of this study. Systematic monitoring programs are urgently needed to understand the present environmental state of Albanian rivers and other aquatic ecosystems to characterize the main sources of pollution and to lay the basis for political guidelines to improve the ecological situation
ANANALYTICAL STUDY OF MARBLE CONSOLIDATION BY OXALATE PRECIPITATION USING DENSITY, FTIR AND POWDER-XRD MEASUREMENTS
oai:ojs2.www.jepm.rs.ba:article/28Our recent study on consolidation of marble samples with the purpose of culture heritage protection occurred by periodical calcium oxalate precipitation on top of quasi parallelepipedic samples. The overall process consisting of three stages of treatment, starting with 5 % calcium acetate solution for 60 minutes at 20°C, a draining step at 70°C for 30 min, followed by a treatment with 5 % ammonium sulfate solution, it followed with the third stage which includes the treatment with 5% ammonium oxalate solution revealed a continuous density increace, determined using ethanol. As the natural samples had an initial density of 2.5871 g/cm3 , it increased up to 2.6980 g/cm3 for 50 times treatments. The precipitation of oxalate on top of calcium carbonate substrate, in form of calcite, revealed two distinguished infra-red bands, at 1316 cm-1 and 1624 cm-1 unsymmetrically located around the carbonate one at 1426 cm-1 .The intensity of the bands was proportional to the number of treatments. The continuous surface coverage investigated in parallel by powder XRD evidenced the presence of whewellite crystallites deposited on top of calcite, and their intensity increasing as well with the number of treatments. This method exhibits a reliable oxalate coverage of marble sample surfaces which doesn’t influence considerably their water solubility
Blood dynamics of mercury and selenium in northern elephant seals during the lactation period
The effects of reproduction and maternal investment (i.e., milk transfer) on trace element levels remain poorly understood in marine mammals. We examined the blood dynamics of mercury (Hg) and selenium (Se) during lactation in the northern elephant seal (Mirounga angustirostris), a top predator from the North Pacific Ocean. Total Hg and Se levels were measured in whole blood and milk of 10 mother-pup pairs on days 5 and 22 of lactation. Both Hg and Se were transferred to offspring through the milk. Results suggested that the maternal transfer of Se was prominent during lactation, whereas the Hg transfer was larger during gestation. The lactation period affected Hg and Se levels in the blood of elephant seal mothers and pups. Physiological processes and their relationship to body condition should be considered carefully when interpreting trace element levels in the framework of biomonitoring.Peer reviewe
Cycle time mapping automated coremanufacturing
Detta examensarbete är utfört på Scania Södertälje i syftet att kartlägga cykeltider av Kärnamakeri avdelning på nya gjuteriet. Mätning alla av cykeltider för att sen kartläggas görs för att tydligt visualisera utrustnings samt avdelnings kapacitet. Projektet inleddes med insamling av all nödvändig information som underlag för genomförande av arbetet och därefter valdes lämpliga metoder för att uppnå målen. Resultatet visar en berglipig cykeltidskartläggning över hela avdelningen med en tydlig identifiering av flaskhalsarna som styr hela produktionen. Med hjälp av den valda metoden analyserades flaskhalsarna djupnade för att hitta möjliga slöserier i form av onödiga rörelser för att utföra processen. Förbättringsförslag presenterades som avslutning del av projektens resultat samt även som rekommendationer för fortsatt förbättringsarbete att optimera produktionskapacitet.This thesis project is implemented at Scania Södertälje with the aim of mapping cycle times of the core making department at the new foundry. All measurement of cycle times to then be mapped is done to clearly visualize equipment and department capacity. The project began with the collection of all necessary information as a basis for carrying out the work and then suitable methods were chosen to achieve the goals. The result shows a pronounced cycle time mapping across the entire department with a clear identification of the bottlenecks that control the entire production. Using the chosen method, the bottlenecks were analysed in depth to find possible waste in the form of unnecessary movements to carry out the process. Improvement proposals were presented as a concluding part of the project's results and also as recommendations for continued improvement work to optimize production capacity
Cycle time mapping automated coremanufacturing
Detta examensarbete är utfört på Scania Södertälje i syftet att kartlägga cykeltider av Kärnamakeri avdelning på nya gjuteriet. Mätning alla av cykeltider för att sen kartläggas görs för att tydligt visualisera utrustnings samt avdelnings kapacitet. Projektet inleddes med insamling av all nödvändig information som underlag för genomförande av arbetet och därefter valdes lämpliga metoder för att uppnå målen. Resultatet visar en berglipig cykeltidskartläggning över hela avdelningen med en tydlig identifiering av flaskhalsarna som styr hela produktionen. Med hjälp av den valda metoden analyserades flaskhalsarna djupnade för att hitta möjliga slöserier i form av onödiga rörelser för att utföra processen. Förbättringsförslag presenterades som avslutning del av projektens resultat samt även som rekommendationer för fortsatt förbättringsarbete att optimera produktionskapacitet.This thesis project is implemented at Scania Södertälje with the aim of mapping cycle times of the core making department at the new foundry. All measurement of cycle times to then be mapped is done to clearly visualize equipment and department capacity. The project began with the collection of all necessary information as a basis for carrying out the work and then suitable methods were chosen to achieve the goals. The result shows a pronounced cycle time mapping across the entire department with a clear identification of the bottlenecks that control the entire production. Using the chosen method, the bottlenecks were analysed in depth to find possible waste in the form of unnecessary movements to carry out the process. Improvement proposals were presented as a concluding part of the project's results and also as recommendations for continued improvement work to optimize production capacity
STUDY OF PM 10 LEVELS IN URBAN AIR OF TIRANA (VASIL SHANTO CROSS-ROAD) AND STATISTICAL ANALYSIS OF DATA COLLECTED
The main objective of this paper is to analyze the PM 10 concentration levels in one of the main Tirana city crossroad and to evaluate how these levels are influenced by road traffic density and weather conditions. The measurements have been carried out from May to July 2012, by the Laboratory of Chemistry in Faculty of Mathematical Engineering and Physical Engineering. During 70 days, 12-hours particles samples were collected two times in each day, with a total of 140 samples. One-way Analysis of Variance (ANOVA) was applied to the data collected, to statistically confirm if factors, such are the time of sampling (day-night; weekdays-weekend days) and meteorological conditions (day with or without precipitation) have impact on the PM 10 concentration. The average of mass concentration for PM 10 was 34.25 g/m 3 . Only 11.4% of daily concentrations measured exceeded the EU limit value of 50 g/m 3 , whilst all of them were well below the limit value of 150 g/m 3 defined by Albanian Standard of Air Quality. The data obtained are conform the trend described in last years air monitoring reports, which show a reduction of particulate matter level of urban air in Tirana. This demonstrates that actions undertaken on controlling the air pollution sources and improvements made in infrastructure have positively contributed in the air quality
Extração e purificação de enzimas
As enzimas têm uma extraordinária capacidade para catalisar reações metabólicas. Nos últimos anos, tem havido uma rápida evolução na produção de enzimas, tanto experimentalmente como em escala industrial. Neste artigo, descrevemos algumas técnicas importantes de extração e purificação, usadas na produção das enzimas. Também são descritos métodos combinados para produzir enzimas de alto grau de pureza.
Palavras-Chave: enzimas, extração, isolamento, purificaçã
Development of the Concept of creation of nanocrystalline ferromagnetic by a method of powder metallurgy
In article the concept of creation of nanocrystalline ferromagnetic by methods of the powder metallurgy, based on use of mecahnosynthesis for reception of a powder of an amorphous alloy Fe73,5Cu1Nb3Si13,5B9 and low-temperature technological binders for reception by dry pressing with the subsequent heat treatment magnetic cores with sufficient mechanical durability and a demanded complex of electromagnetic properties is presented
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