Addition of Al(OH)3 versus AlO(OH) nanoparticles on the optical,thermo-mechanical and heat/oxygen transmission properties of microfibrillated cellulose films

Cellulose - Differently structured aluminum (tri/mono) hydroxide (Al(OH)3 /AlO(OH)) nanoparticles were prepared and used as thermal-management additives to microfibrillated cellulose (MFC),...     

Characteristics of suspended matter in the River Sava watershed,Slovenia

A combination of C/N ratios, δ¹³C and δ¹⁵N values in suspended matter was used to examine the seasonal (late summer 2004 and spring 2005) relationship with hydrological characteristics of the River Sava watershed in Slovenia. The values of C/N ratios range from 1.2 to 19.1, δ¹³C values range from?29.2 to?23.0 ‰ and δ¹⁵N values from 0.5 to 16.7 ‰ and indicate that the samples are a mixture of two end members: modern soils and plant litter. A simple mixing model was used to indicate that soil organic carbon prevails over plant litter and contributes more than 50% of suspended material. The calculated annual particulate organic carbon flux is estimated as 5.2×10¹⁰ g C/year, the annual particulate nitrogen flux 8.5×10⁹ g N/year and the total suspended solid flux is estimated to be 1.3×10¹² g/year. Anthropogenic impact was detected only in a tributary stream of the River Sava, which is located in an agriculture–industrial area and is reflected in higher δ¹⁵N values in suspended matter and high nitrate concentrations in the late summer season.     

Surface characterization of stepwise oxidized spruce thermomechanical pulp samples by different analytical methods

An investigation of the fiber samples with various amounts of lignin, hemicelluloses and cellulose was conducted by means of dye adsorption, spectrometric and chemical analyses. Five fiber samples were prepared by the oxidation of unbleached Norway spruce thermo-mechanical pulp with acidic potassium permanganate solution. Each sample was oxidized with defined amount of KMnO₄ and the degree of oxidation was determined as kappa number. Fibers were additionally characterized by conductometric titration, the determination of hemicelluloses and infrared spectrometry. Sorption of various types of dye, namely Methylene Blue (MB), Crystal Violet (CV) and Astra Blue (AB) on the fiber surface was studied and compared to the kappa number and other fiber characteristics. The adsorption of MB and CV is found to follow the amount of anionic (carboxylic) groups, which at first increase and later decrease toward the final stages of oxidation. The behavior of AB is nearly the opposite, its adsorption increases with the depletion of lignin and carboxylate groups, pointing to a different mechanism of AB binding on fibers.     

Mytilus galloprovincialis as a bioindicator of environmental conditions: the case of the eastern coast of the Adriatic Sea

The marine mussel Mytilus galloprovincialis lives attached to the surface of hard substrata, where its exposure and relative immobility allow it to record changes in ambient seawater. It is also found along the eastern coast of the Adriatic Sea. Oxygen and carbon isotopes were analysed for calcite and aragonite in separate shell layers, while major, minor and trace elements in the bulk shell were analysed to evaluate environmental conditions such as the temperature of carbonate deposition, freshwater influence and locations of anthropogenic pollution. We found that, on average, aragonite is enriched by 1.1‰ in ¹³C and by 0.2‰ in ¹⁸O compared with calcite. The calculated temperatures for M. galloprovincialis shell growth from the investigated area range from 13.4 to 20.9 °C for calcite and from 16.6 to 23.1 °C for aragonite. According to the δ¹⁸O and δ¹³C values of shell layers, we can separate the investigated area into three locations: those with more influence of freshwater, those with less influence of freshwater and those with marine environments. The highest concentrations of manganese, barium, boron, arsenic, nickel and chromium were observed in shells from Omi?, Ba?vice and Zabla?e (Central Adriatic) and Sv. Ivan (South Adriatic), where chemical and heavy industries are located and where sewage is known to be discharged into coastal areas. The highest concentrations of zinc, lead and copper were measured in samples from Pula, Rijeka and Gru?, where there are also ports in addition to industry.