24 research outputs found

    Pranje domaće vune u Hrvatskoj i utjecaj na okoliš

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    Wool and wastewaters from scouring can be a mixed blessing - a useful technological raw material or an environmental problem. If wool is scoured with no control, as the case most often is in Croatia, the wastewater released could endanger the environmental stability of the existing water systems. Since the interest has been growing recently for processing domestic wool, which also presents a considerable hazard of polluting water because of unskilled scouring and uncontrolled wastewater release into the natural water flows, we have organized investigations aimed at determining potentially dangerous ecological loads on the Croatian water systems, caused by scouring domestic wool. The results obtained indicate that improper disposal of the wool and/or uncontrolled release of wastewater from scouring present a considerable environmental hazard. We have concluded that impacts on the environment of scouring domestic wool in Croatia are the same as impacts on the environment obtained by normal functioning of a town of 1700_2000 inhabitants.Vuna i otpadne vode od pranja vune mogu biti korisna tehnološka sirovina ili su pak ekološki problem. Ukoliko se vuna nekontrolirano pere, kao što je to najčešće slučaj u Hrvatskoj, ispuštene otpadne vode mogu ugroziti prirodnu ekološku stabilnost postojećih vodenih sustava. S obzirom da je u posljednje vrijeme povećano zanimanje za preradu domaće vune, a time i opasnost od onečišćenja voda zbog nestručnog pranja vune i nekontroliranog ispuštanja otpadne vode od pranja vune u prirodne vodotokove svrha ovog rada bila je odrediti potencijalno moguće ekološko opterećenje vodenih sustava Hrvatske uzrokovano pranjem domaće vune. Rezultati istraživanja pokazuju da nekontrolirano odlaganje vune i/ili otpadne vode od pranja domaće vune u Hrvatskoj predstavlja značajnu opasnost za okoliš, koja je ekvivalentna onečišćenju koje nastaje normalnim funkcioniranjem grada s 1700 do 2000 stanovnika

    Effect of galactomannan hydrocolloids on gelatinization and retrogradation of tapioca and corn starch

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    The aim of the present study was to investigate the effect of galactomannan hydrocolloids (guar gum and locust bean gum) on gelatinization and retrogradation of tapioca and corn starch. Differential scanning calorimetry (DSC) was used to characterize the behaviour of tapioca and corn starch with and without additives. Results showed that guar gum and locust bean gum retarded the retrogradation of tapioca and corn starch at both investigated temperatures (4 and 25 °C). Guar gum retarded retrogradation of tapioca starch more than locust bean gum, on the other hand, locust bean gum had a greater effect on reduction of the recrystallization of corn starch. Temperatures of gelatinization did not vary significantly in starch-hydrocolloid systems. Additions of galactomannan hydrocolloids caused a decrease in gelatinization enthalpy of both starches

    An Alternative Procedure to Quantify Soot in Engine Oil by Ultraviolet-Visible Spectroscopy

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    "This is an Accepted Manuscript of an article published by Taylor & Francis in Tribology Transactions on 02-11-2019, available online: https://www.tandfonline.com/doi/full/10.1080/10402004.2019.1645255."[EN] Due to new pollutant emissions standards, internal combustion engines need several emission control strategies (and related procedures) such as exhaust gas recirculation, diesel/gasoline particulate filters, and selective catalyst reduction that allow them to comply with complete requirements defined on those standards. These strategies result in faster degradation of engine oil, one of the most relevant consequences of which is an increase in soot contamination level. All of these strategies facilitate soot generation. Consequently, soot is one of the most important contaminants present in engine oil. The main technique to measure the content of soot in oil is thermogravimetric analysis (TGA), but this technique has certain limitations. TGA requires a long and specific procedure and has limitations in measuring small concentrations of soot in oil. Therefore, the design of an alternative technique to quantify soot in oil is relevant. One alternative is Fourier transform infrared (FTIR) spectroscopy, but it also has limitations related to low concentrations of soot in oil. This work presents an alternative technique based on ultraviolet-visible (UV-Vis) spectroscopy that allows quantification of small soot contents in used engine oil samples and avoids potential interference from other typical contaminants or those related to measurement processes, such as sample cuvette material.Antonio Garcia-Barbera was supported through the Programa Nacional de Formacion de Recursos Humanos de Investigacion of Spanish Ministerio de Ciencia e Innovacion (Grant Number BES-2016-078073).Macian Martinez, V.; Tormos, B.; Ruiz-Rosales, S.; García-Barberá, A. (2019). An Alternative Procedure to Quantify Soot in Engine Oil by Ultraviolet-Visible Spectroscopy. Tribology Transactions. 62(6):1063-1071. https://doi.org/10.1080/10402004.2019.1645255S10631071626Squaiella, L. L. F., Martins, C. A., & Lacava, P. T. (2013). Strategies for emission control in diesel engine to meet Euro VI. Fuel, 104, 183-193. doi:10.1016/j.fuel.2012.07.027Piock, W., Hoffmann, G., Berndorfer, A., Salemi, P., & Fusshoeller, B. (2011). Strategies Towards Meeting Future Particulate Matter Emission Requirements in Homogeneous Gasoline Direct Injection Engines. SAE International Journal of Engines, 4(1), 1455-1468. doi:10.4271/2011-01-1212Johnson, B. T. (2008). Diesel Engine Emissions and Their Control. Platinum Metals Review, 52(1), 23-37. doi:10.1595/147106708x248750Johnson, T. V. (2008). Diesel Emission Control in Review. SAE International Journal of Fuels and Lubricants, 1(1), 68-81. doi:10.4271/2008-01-0069Mohan, B., Yang, W., & Chou, S. kiang. (2013). Fuel injection strategies for performance improvement and emissions reduction in compression ignition engines—A review. Renewable and Sustainable Energy Reviews, 28, 664-676. doi:10.1016/j.rser.2013.08.051ALKEMADE, U., & SCHUMANN, B. (2006). Engines and exhaust after treatment systems for future automotive applications. Solid State Ionics, 177(26-32), 2291-2296. doi:10.1016/j.ssi.2006.05.051Bensaid, S., Caroca, C. J., Russo, N., & Fino, D. (2011). Detailed investigation of non-catalytic DPF regeneration. The Canadian Journal of Chemical Engineering, 89(2), 401-407. doi:10.1002/cjce.20408E, J., Xie, L., Zuo, Q., & Zhang, G. (2016). Effect analysis on regeneration speed of continuous regeneration-diesel particulate filter based on NO 2 -assisted regeneration. Atmospheric Pollution Research, 7(1), 9-17. doi:10.1016/j.apr.2015.06.012Tripathi, A., & Vinu, R. (2015). Characterization of Thermal Stability of Synthetic and Semi-Synthetic Engine Oils. Lubricants, 3(1), 54-79. doi:10.3390/lubricants3010054Karacan, Ö., Kök, M. V., & Karaaslan, U. (1999). Journal of Thermal Analysis and Calorimetry, 55(1), 109-114. doi:10.1023/a:1010136222719Heredia-Cancino, J. A., Ramezani, M., & Álvarez-Ramos, M. E. (2018). Effect of degradation on tribological performance of engine lubricants at elevated temperatures. Tribology International, 124, 230-237. doi:10.1016/j.triboint.2018.04.015Wattrus, M. (2013). Fuel Property Effects on Oil Dilution in Diesel Engines. SAE International Journal of Fuels and Lubricants, 6(3), 794-806. doi:10.4271/2013-01-2680Sharma, V., Uy, D., Gangopadhyay, A., O’Neill, A., Paxton, W. A., Sammut, A., … Aswath, P. B. (2016). Structure and chemistry of crankcase and exhaust soot extracted from diesel engines. Carbon, 103, 327-338. doi:10.1016/j.carbon.2016.03.024Pfau, S. A., La Rocca, A., Haffner-Staton, E., Rance, G. A., Fay, M. W., Brough, R. J., & Malizia, S. (2018). Comparative nanostructure analysis of gasoline turbocharged direct injection and diesel soot-in-oil with carbon black. Carbon, 139, 342-352. doi:10.1016/j.carbon.2018.06.050George, S., Balla, S., Gautam, V., & Gautam, M. (2007). Effect of diesel soot on lubricant oil viscosity. Tribology International, 40(5), 809-818. doi:10.1016/j.triboint.2006.08.002Antusch, S., Dienwiebel, M., Nold, E., Albers, P., Spicher, U., & Scherge, M. (2010). On the tribochemical action of engine soot. Wear, 269(1-2), 1-12. doi:10.1016/j.wear.2010.02.028Green, D. A., & Lewis, R. (2008). The effects of soot-contaminated engine oil on wear and friction: A review. Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering, 222(9), 1669-1689. doi:10.1243/09544070jauto468Bredin, A., Larcher, A. V., & Mullins, B. J. (2011). Thermogravimetric analysis of carbon black and engine soot—Towards a more robust oil analysis method. Tribology International, 44(12), 1642-1650. doi:10.1016/j.triboint.2011.06.002VAN DE VOORT, F. R., SEDMAN, J., COCCIARDI, R. A., & PINCHUK, D. (2006). FTIR Condition Monitoring of In-Service Lubricants: Ongoing Developments and Future Perspectives. Tribology Transactions, 49(3), 410-418. doi:10.1080/10402000600781432Van de Voort, F. R., Ghetler, A., García-González, D. L., & Li, Y. D. (2008). Perspectives on Quantitative Mid-FTIR Spectroscopy in Relation to Edible Oil and Lubricant Analysis: Evolution and Integration of Analytical Methodologies. Food Analytical Methods, 1(3), 153-163. doi:10.1007/s12161-008-9031-6Ess, M. N., Ferry, D., Kireeva, E. D., Niessner, R., Ouf, F.-X., & Ivleva, N. P. (2016). In situ Raman microspectroscopic analysis of soot samples with different organic carbon content: Structural changes during heating. Carbon, 105, 572-585. doi:10.1016/j.carbon.2016.04.056Russo, C., Apicella, B., Lighty, J. S., Ciajolo, A., & Tregrossi, A. (2017). Optical properties of organic carbon and soot produced in an inverse diffusion flame. Carbon, 124, 372-379. doi:10.1016/j.carbon.2017.08.07

    Effect of galactomannan hydrocolloids on gelatinization and retrogradation of tapioca and corn starch

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    original scientific paper Summary The aim of the present study was to investigate the effect of galactomannan hydrocolloids (guar gum and locust bean gum) on gelatinization and retrogradation of tapioca and corn starch. Differential scanning calorimetry (DSC) was used to characterize the behaviour of tapioca and corn starch with and without additives. Results showed that guar gum and locust bean gum retarded the retrogradation of tapioca and corn starch at both investigated temperatures (4 and 25 °C). Guar gum retarded retrogradation of tapioca starch more than locust bean gum, on the other hand, locust bean gum had a greater effect on reduction of the recrystallization of corn starch. Temperatures of gelatinization did not vary significantly in starch-hydrocolloid systems. Additions of galactomannan hydrocolloids caused a decrease in gelatinization enthalpy of both starches

    Mathematical modelling of bioethanol production from raw sugar beet cossettes in a horizontal rotating tubular bioreactor

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    Alternative to the use of fossil fuels are biofuels (e.g., bioethanol, biodiesel and biogas), which are more environmentally friendly and which can be produced from different renewable resources. In this investigation, bioethanol production from raw sugar beet cossettes (semi-solid substrate) by yeast Saccharomyces cerevisiae in a horizontal rotating tubular bioreactor (HRTB) was studied. Obtained results show that HRTB rotation mode (constant or interval) and rotation speed have considerable impact on the efficiency of bioethanol production in the HRTB. The main goal of this research was to develop a non-structural mathematical model of bioethanol production from raw sugar beet cossettes in the HRTB. The established mathematical model of bioethanol production in the HRTB describes substrate utilization and product formation (glycerol, ethanol and acetate) and presumes negative impact of high substrate concentration on the working microorganism (substrate inhibition) by using Andrews inhibition kinetics. All simulations of bioethanol production in the HRTB were performed by using Berkeley Madonna software, version 8.3.14 (Berkeley Madonna, Berkeley, CA, USA). The established non-structural bioprocess model describes relatively well the bioethanol production from raw sugar beet cossettes in the HRTB

    A pragmatic approach to the use of inotropes for the management of acute and advanced heart failure. an expert panel consensus

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    Inotropes aim at increasing cardiac output by enhancing cardiac contractility. They constitute the third pharmacological pillar in the treatment of patients with decompensated heart failure, the other two being diuretics and vasodilators. Three classes of parenterally administered inotropes are currently indicated for decompensated heart failure, (i) the beta adrenergic agonists, including dopamine and dobutamine and also the catecholamines epinephrine and norepinephrine, (ii) the phosphodiesterase III inhibitor milrinone and (iii) the calcium sensitizer levosimendan. These three families of drugs share some pharmacologic traits, but differ profoundly in many of their pleiotropic effects. Identifying the patients in need of inotropic support and selecting the proper inotrope in each case remain challenging. The present consensus, derived by a panel meeting of experts from 21 countries, aims at addressing this very issue in the setting of both acute and advanced heart failure

    Scouring of Domestic Wool in Croatia and its Impacts on the Environment

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    Wool and wastewaters from scouring can be a mixed blessing - a useful technological raw material or an environmental problem. If wool is scoured with no control, as the case most often is in Croatia, the wastewater released could endanger the environmental stability of the existing water systems. Since the interest has been growing recently for processing domestic wool, which also presents a considerable hazard of polluting water because of unskilled scouring and uncontrolled wastewater release into the natural water flows, we have organized investigations aimed at determining potentially dangerous ecological loads on the Croatian water systems, caused by scouring domestic wool. The results obtained indicate that improper disposal of the wool and/or uncontrolled release of wastewater from scouring present a considerable environmental hazard. We have concluded that impacts on the environment of scouring domestic wool in Croatia are the same as impacts on the environment obtained by normal functioning of a town of 1700-2000 inhabitants

    Pharmaceutical principles of acid inhibitors: unmet needs

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    Despite the well-established benefits of currently approved delayed-release proton pump inhibitors (PPIs) in the treatment of acid-related diseases, the unmet needs are still present and although often frustrating, they challenge clinicians. The unmet needs relate to the lack of complete control of acid secretion with oral PPI administration in the management of patients with gastroesophageal symptoms. These substantial groups of patients, who do not respond completely to standard doses of PPIs, are nonresponders, and their lack of response should be considered as PPI failure. Several mechanisms could explain PPI failure: differences in pharmacokinetics, PPI formulation, dosing time and diet, noncompliance, transient lower esophageal sphincter relaxations, esophageal hypersensitivity, and nocturnal acid breakthrough. To increase the quality of life of these patients and avoid multiple medical consultations and unnecessary investigations, we have to go one step forward and use combined therapy or look towards new treatments beyond acid suppression
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