Marko Ukrainczyk

University of Limerick

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Damir Kralj

Rudjer Boskovic Institute

Jasminka Kontrec

Rudjer Boskovic Institute

Matija Gredičak

Rudjer Boskovic Institute

ÅC

Åke C. Rasmuson

KTH Royal Institute of Technology

Mladen Brnčić

University of Zagreb

Branko Tripalo

University of Zagreb

JŻ

Jacek Żegliński

University of Limerick

Damir Ježek

University of Zagreb

Ana‐Sunčana Smith

Rudjer Boskovic Institute

Robert Stepić

Rudjer Boskovic Institute

Cooperative Institutions

University of Zagreb

Rudjer Boskovic Institute

Karlsruhe Institute of Technology

University of Limerick

Centre National de la Recherche Scientifique

Technical University of Munich

University of Leeds

University College London

Friedrich-Alexander-Universität Erlangen-Nürnberg

University of Manchester

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Precipitation of mesoporous calcium carbonate nanoparticles

Jasminka Kontrec Marko Ukrainczyk Damir Kralj

Postupci priprave kalcijeva karbonata, specificnih fizikalno-kemijskih svojstava, intenzivno se istražuju zbog njegove siroke uporabe u razlicitim industrijama, poput plasticne, papirne, prehrambene, farmaceutske i dr. Najvise istraživanja odnosi se na mikrometarski kalcijev karbonat te u posljednje vrijeme na kalcijev karbonat nanometarskih dimenzija. Sve veci interes usmjeren je na pripravu poroznog kalcijeva karbonata i njegovu uporabu kao katalizatora i potencijalnog nosaca lijekova. U ovom je radu porozni kalcijev karbonat pripravljen postupkom upuhivanja CO2 u suspenziju kalcijeva hidroksida. Ovaj postupak iskljucuje efekte stranih iona u taložnom sustavu buduci da su prisutni samo konstituirajuci ioni kalcija i karbonata. Osim toga plinoviti ugljicni dioksid i kalcijev hidroksid su lako dostupni i jeftini materijali te je ovaj postupak nasao siroku primjenu. Napredovanje taloženja je praceno mjerenjem elektricne provodnosti (mjera prezasicenosti) tijekom vremena. Istraživanja su provedena u rasponu temperature 25 ○C < θ < 45 ○C. Varirane su masene koncentracije suspenzije kalcijeva hidroksida. Morfologija tako pripravljenih kalcijevih karbonata je analizirana pretražnom i transmisijskom elektronskom mikroskopijom, te su im određene raspodjela velicina cestica i specificna povrsina. Nađeno je da je kalcit jedini istaloženi polimorf. Njegova specificna povrsina se povecava s povecanjem prezasicenosti te sa smanjenjem temperature. Mezoporozni kalcit je istaložio u uvjetima vise prezasicenosti pri 25 oC. Cestice su romboedarske morfologije velicine 200 nm s promjerom supljine 50 nm. Diskutiran je mehanizam nastajanja takvih cestica.

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Precipitation of mesoporous nanosized calcium carbonate

Jasminka Kontrec Marko Ukrainczyk Ljerka Brečević Damir Kralj

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Adsorption of Aspartate Derivatives to Calcite Surfaces in Aqueous Environment

Crystal Growth & Design (2020)

Robert Stepić Lara Jurković Ksenia Klementyeva Marko Ukrainczyk Matija Gredičak

In many living organisms, biomolecules interact favorably with various surfaces of calcium carbonate. In this work, we considered the interactions of aspartate (Asp) derivatives, as models of complex biomolecules, with calcite. Using kinetic growth experiments, we investigated the inhibition of calcite growth by Asp, Asp2, and Asp3.This entailed the determination of a step-pinning growth regime as well as the evaluation of the adsorption constants and binding free energies for the three species to calcite crystals. These latter values are compared to free energy profiles obtained from fully atomistic molecular dynamics simulations. When a flat (104) calcite surface is used in the models, the measured trend of binding energies is poorly reproduced. However, a more realistic model comprised of a surface with an island containing edges and corners yields binding energies that compare very well with experiments. Surprisingly, we find that most binding modes involve the positively charged ammonium group. Moreover, while attachment of the negatively charged carboxylate groups is also frequently observed, it is always balanced by the aqueous solvation of an equal or greater number of carboxylates. These effects are observed on all calcite features including edges and corners, the latter being associated with dominant affinities to Asp derivatives. As these features are also precisely the active sites for crystal growth, the experimental and theoretical results point strongly to a growth inhibition mechanism, whereby these sites become blocked, preventing further attachment of dissolved ions and halting further growth.

Carboxylate

10.1021/acs.cgd.0c00061

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Interactions of phosphate and phosphonate with calcite surface

Jan Stelling Frank Heberling Marko Ukrainczyk Alexandra Kelly Nothstein Thomas Neumann

Phosphonate

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Interaction of salicylic acid with calcite

Marko Ukrainczyk Damir Kralj

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Taloženje mezoporoznih nanočestica kalcijeva karbonata

Jasminka Kontrec Marko Ukrainczyk Damir Kralj

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Polymorphic composition and morphology of calcium carbonate as a function of ultrasonic irradiation

Crystal Research and Technology (2014)

Branka Njegić Džakula Jasminka Kontrec Marko Ukrainczyk Sanja Sviben Damir Kralj

This paper reports on the precipitation of CaCO 3 polymorphs, having various crystal morphologies under different conditions. In particular, systems that were subject to ultrasonic irradiation were compared to the corresponding reference systems in the absence of such a treatment. The application of ultrasonic irradiation predominantly resulted in a change of particle size distribution and polymorphic composition of the precipitate, in comparison to the reference systems. Thus, it was found that the supersaturation and temperature influenced the size distribution, in both the reference and sonicated systems. A mixture of calcite, vaterite and aragonite was obtained in all reference systems, at 25 °C. At this temperature, the sonication caused the vaterite content to increase, while aragonite was not detected. In reference and sonicated systems at 80 °C, only aragonite precipitated. The results also indicate that the principle parameter responsible for the morphology of vaterite was the initial supersaturation: at higher supersaturation spherical vaterite particles precipitated, while at lower supersaturation hexagonal platelets were obtained. The morphological investigations also indicated different mechanisms of vaterite formation in the systems in which precipitation was initiated at higher supersaturation: spherulitic growth of vaterite was observed in sonicated systems, while the aggregation of primary particles was predominant in the reference systems. At lower supersaturation, the effect of c (Ca 2+ )/ c (CO 3 2− ) on the morphology of hexagonal platelets of vaterite was observed as well. By varying the c (Ca 2+ )/ c (CO 3 2− ), significant changes of the polymorphic composition were observed only in the sonicated systems, at 25 °C.

Vaterite

Supersaturation

Sonication

Morphology

10.1002/crat.201300388

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Influence of Whey Protein Addition and Feed Moisture Content on Chosen Physicochemical Properties of Directly Expanded Corn Extrudates

Food and Bioprocess Technology (2009)

Mladen Brnčić Tomislav Bosiljkov Marko Ukrainczyk Branko Tripalo Suzana Rimac Brnčić

Die swell

Lightness

10.1007/s11947-009-0273-0

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Effect of twin-screw extrusion parameters on mechanical hardness of direct-expanded extrudates

Sadhana (2006)

Mladen Brnčić Branko Tripalo Damir Ježek Damir Semenski Nenad Drvar

Die swell

Universal testing machine

10.1007/bf02715911

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Biodiesel production promotion - Countrywide Feasibility Study For a Potential Croatian Biodiesel Industry, Final Technical Report

Fatim Ali Mohamed Julije Domac Velimir Šegon Biljana Kulišić Branko Tripalo

The report summarised the work carried out as a part of technical assistance from UNIDO to the Government of Croatia in order to support efforts in establishing biodiesel industry in Croatia. This should lead to reduction of Croatian energy dependency and help improve the quality of the environment and diversify production and employment in agriculture and industry. The production and use of biodiesel to replace fossil fuels in transport also contribute to meeting signed commitment and targets resulting from EU Biofuels and other Directives and Kyoto Protocol. The intention of the report is to provide information and knowledge to enable taking decisions on the appropriate production chain and economic model to adopt in function of available and potential feedstock, market segments, distribution channels, promotional policies and financial mechanisms, and to provide guidelines for regulatory measures to be put in place to promote biodiesel production and market development. Biodiesel and its blends represents an excellent substitute of mineral diesel which offers a variety of benefits, increased employment, development of rural areas, increased security of energy supply and a better overall trade balance. However, biodiesel is still not cost competitive with mineral diesel without subsidies or tax incentives except in cases where petroleum prices are high in the extreme and vegetable oil prices are low. Feedstock cost is main factor affecting the competitiveness and profitability of biodiesel production. The current and potential feedstock, in terms of both availability and price, are identified and quantified, as well as, the factors that may impact the identified feedstock use for biodiesel. Consequently, the importance of the Government intervention with appropriate measures was highlighted in order to encourage the production of rapeseed and other oilseed for non-food purpose. The measures will have to ensure, at least, the quantities of feedstock required for the planned production of biodiesel, increase the yield of rapeseed per hectare and regulate market channels for produced rapeseed and include financial incentives and continuous education and expert support for farmers as the most important components. To decrease the unit production costs it is necessary to use a lower cost feedstock and or to increase the economic performance of production by carefully choosing the location of biodiesel processing plant. The use of waste edible oils as possible complimentary source or imports of cheap vegetable oils from the global market represent an interesting option especially in the initial phase of biodiesel production in Croatia. The selection of biodiesel production location in a harbour for example would provide cheaper access for transportation of feedstock and biodiesel products. The selection of appropriate process technology and plant production capacity is considered important factors influencing the financial and economic performance of the whole production operation. The selection should take into consideration a variety of factors including feedstock availability and quality, ability to process multi Promotion of Biodiesel Production in Croatia – Final Report feedstock, as well as, available market, investor intentions and plans, etc. There are numerous technologies available on the market today. However, the increasing requirements for producing high quality biodiesel according to strict fuel standards has been the driving force for switching to technologies with accurate cleaning stepsfor the final biodiesel which usually implies large scale production capacity. The results of the financial analysis undertaken show that the larger the scale of production the better the results in terms of all financial and economic indicators. Having in mind the goal of establishing a sustainable biodiesel production in Croatia and considering present higher costs of production compared to mineral diesel, it is necessary to develop and put in place a stable mechanism of financial incentives. This would include de-taxation, and, therefore, would result in a direct loss of Government revenue. However, the undertaken input-output analysis of the rapeseed biodiesel production chain has indicated that biodiesel production will contribute directly and indirectly to additional Government revenue, which would compensate for the loss in tax revenues. Due to its nature, biodiesel production and utilisation involve various sectors, interest groups and market players and like other renewable energy sources, biodiesel needs to be put in the right context and dealt carefully by integrating its socio-economic and environmental added values into the economic model.

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