The mechanochemical synthesis of calcium oxalate

Ova studija prikazuje mehanokemijsku sintezu kalcijeva oksalata u planetarnom kugličnom mlinu, bez i uz prisutnost otapala. Dosadašnja istraživanja su uglavnom bila usmjerena na otopinsku sintezu kalcijeva oksalata. U ovom radu opisujemo drugačiji pristup, koji će donijeti nova saznanja o sintezi kristala kalcijeva oksalata, a koje su uzrokovane utjecajem mehaničke energije. Cilj istraživanja je sinteza, identifikacija i karakterizacija pojedine oksalatne hidratne faze sintetizirane iz kalcijevih soli (klorida, nitrata i sulfata). Ispitivan je utjecaj brzine mljevenja i praćena je reakcija u ovisnosti o vremenu sinteze. Strukturalna i termička svojstva uzoraka ispitana su FTIR spektroskopijom i termogravimetrijskom analizom (TGA). Morfološke karakteristike kalcijeva oksalata te raspodjela veličine čestica određene su optičkom mikroskopijom i dinamičkim raspršenjem svjetlosti (DLS).In this work, mechanochemical synthesis of calcium oxalate was done in planetary ball mill, with and without addition of water as a solvent. Previous researches were primarily focused on calcium oxalate synthesis in a solution. Here we report a different approach which may contribute to new findings in calcium oxalate crystal synthesis caused by an influence of mechanical energy. The aim of this study is synthesis, identification and characterization of particular oxalate hydrate phase synthesized with calcium salts (chloride, nitrate and sulphate). The effects of grinding speed and reaction duration regarding the time of synthesis were investigated. Structural and thermal sample properties were studied by FTIR spectroscopy and thermogravimetric analysis (TGA). Morphologic characteristics of calcium oxalate and size distribution were measured by optical microscopy and dynamic light scattering (DLS)

The process of obtaining quartz sand size fraction -0.4 + 0.05 mm for use in water glass production

The paper presents the process of quartz sand processing from the „Bijela Stijena“-Skočić deposit in the plant „Kesogradnja d.o.o.“ at Kozluk near Zvornik, Republic of Srpska. Bearing in mind the fact that this quartz sand is used for water glass production in the company „Birač“ - Zvornik or „Alumina“ Zvornik, it was necessary to meet the quality requirements prescribed by that industrial production. Thus, the required size was -0.4+0.05 mm and the Fe2O3 content was maximum of 0.04%. Based on the laboratory tests, a technological scheme for the quartz raw material valorization was conceived in the separation of the company „Kesogradnja d.o.o.“. The obtained results showed that quartz sand for water glass size fraction -0.4+0.05 mm could be obtained in the plant. Also, by introducing a magnetic concentration after washing and grading, the Fe2O3 content was reduced from 0.131% as it is in the initial sample to 0.038% which meets the required conditions from the water glass producers

Mechanochemical synthesis of calcium oxalate

Ova studija prikazuje mehanokemijsku sintezu kalcijeva oksalata u planetarnom kugličnom mlinu, bez i uz prisutnost otapala. Dosadašnja istraživanja su uglavnom bila usmjerena na otopinsku sintezu kalcijeva oksalata. U ovom radu opisujemo drugačiji pristup, koji će donijeti nova saznanja o sintezi kristala kalcijeva oksalata, a koje su uzrokovane utjecajem mehaničke energije. Cilj istraživanja je sinteza, identifikacija i karakterizacija pojedine oksalatne hidratne faze sintetizirane iz kalcijevih soli (klorida, nitrata i sulfata). Ispitivan je utjecaj brzine mljevenja i praćena je reakcija u ovisnosti o vremenu sinteze. Strukturalna i termička svojstva uzoraka ispitana su FTIR spektroskopijom i termogravimetrijskom analizom (TGA). Morfološke karakteristike kalcijeva oksalata te raspodjela veličine čestica određene su optičkom mikroskopijom i dinamičkim raspršenjem svjetlosti (DLS)

Water for all : Proceedings of the 7th international scientific and professional conference Water for all

The 7th International Scientific and Professional Conference Water for all is organized to honour the World Water Day by the Josip Juraj Strossmayer University of Osijek, European Hygienic Engineering & Design Group (EHEDG), Danube Parks, Croatian Food Agency, Croatian Water, Faculty of Food Technology Osijek, Faculty of Agriculture in Osijek, Faculty of Civil Engineering Osijek, Josip Juraj Strossmayer University of Osijek Department of Biology, Josip Juraj Strossmayer University of Osijek Department of Chemistry, Nature Park “Kopački rit”, Osijek- Baranja County, Public Health Institute of the Osijek- Baranja County and „Vodovod-Osijek“ -water supply company in Osijek. The topic of World Water Day 2017 was "Wastewater" emphasizing the importance and influence of wastewater treatments on global environment. The international scientific and professional conference Water for all is a gathering of scientists and experts in the field of water management, including chemists, biologists, civil and agriculture engineers, with a goal to remind people about the significance of fresh water and to promote an interdisciplinary approach and sustainability for fresh water resource management. The Conference has been held since 2011. About 300 scientists and engineers submitted 95 abstracts to the 7th International Scientific and Professional Conference Water for all, out of which 33 was presented orally and 62 as posters. 47 full papers were accepted by the Scientific Committee. 38 full papers became the part of the this Proceedings while 9 papers were accepted for publication in Croatian Journal of Food Science and Technology and Electronic Journal of the Faculty of Civil Engineering Osijek - e-GFOS

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Sol-gel synthesis of complex metal oxides with double and triple perovskite-type structure

Perovskit je naziv za porodicu spojeva kristalne strukture čija je opća formula ABX3 gdje je A kation većeg ionskog promjera, B kation manjeg ionskog promjera, a X halogenidni anion ili kisik. U ovome diplomskom radu citratnom dvostupanjskom sol – gel metodom sintetizirani su sloţeni metalni oksidi perovskitne strukture $Sr_{3}Co_{2}TeO_{9}$, $Ba_{3}Co_{2}TeO_{9}$, $Sr_{3}NiTeO_{6}$ te $Ba_{2}NiTeO_{6}$. Nakon prvostupanjskog miješanja prekursora i kompleksacije citratnom kiselinom, u drugom koraku su osušeni uzorci kalcinirani pri 600 ˚C i 1000 ˚C u peći u struji zraka s temperaturom zagrijavanja 2 ˚C/min. Uzorci su karakterizirani cikličkom voltametrijom, infracrvenom spektroskopijom (FT – IR), termogravimetrijskom analizom (TGA), rentgenskom difrakcijom na prahu (PXRD) te su im odreĎena magnetska svojstva SQUID mjerenjima. UtvrĎeno je da su sintetizirani spojevi visoke čistoće te da su veličine kristalita male unatoč visokim temperaturama kalciniranja. $Sr_{3}NiTeO_{6}$ i $Ba_{2}NiTeO_{6}$ pokazuju antiferomagnetska svojstva.Perovskite is the name for a family of compounds with crystal structure of the general formula ABX3 where A is a cation of a larger ionic radius, B is a cation of a smaller ionic radius and X stands for halide or oxide anion. In this diploma thesis, complex metal oxides of perovskite type crystal structure $Sr_{3}Co_{2}TeO_{9}$, $Ba_{3}Co_{2}TeO_{9}$, $Sr_{3}NiTeO_{6}$ and $Ba_{2}NiTeO_{6}$ were synthesized by the citrate sol - gel route. Dried samples were calcined at 600 °C and 1000 °C in a furnace with air flow and at a temperature rate of 2 °C per minute. Samples were characterized by the cyclic voltammetry, infrared spectroscopy (FT –IR), thermogravimetric analysis (TGA), Powder X – ray diffraction (PXRD) while magnetic ground state has been determined using SQUID measurement. Obtained results have revealed that synthesized materials are of high purity and their average crystallite size has remained in nanometer range despite the high calcination temperatures. $Sr_{3}NiTeO_{6}$ and $Ba_{2}NiTeO_{6}$ posses antiferromagnetic properties

The mechanochemical synthesis of calcium oxalate

Ova studija prikazuje mehanokemijsku sintezu kalcijeva oksalata u planetarnom kugličnom mlinu, bez i uz prisutnost otapala. Dosadašnja istraživanja su uglavnom bila usmjerena na otopinsku sintezu kalcijeva oksalata. U ovom radu opisujemo drugačiji pristup, koji će donijeti nova saznanja o sintezi kristala kalcijeva oksalata, a koje su uzrokovane utjecajem mehaničke energije. Cilj istraživanja je sinteza, identifikacija i karakterizacija pojedine oksalatne hidratne faze sintetizirane iz kalcijevih soli (klorida, nitrata i sulfata). Ispitivan je utjecaj brzine mljevenja i praćena je reakcija u ovisnosti o vremenu sinteze. Strukturalna i termička svojstva uzoraka ispitana su FTIR spektroskopijom i termogravimetrijskom analizom (TGA). Morfološke karakteristike kalcijeva oksalata te raspodjela veličine čestica određene su optičkom mikroskopijom i dinamičkim raspršenjem svjetlosti (DLS).In this work, mechanochemical synthesis of calcium oxalate was done in planetary ball mill, with and without addition of water as a solvent. Previous researches were primarily focused on calcium oxalate synthesis in a solution. Here we report a different approach which may contribute to new findings in calcium oxalate crystal synthesis caused by an influence of mechanical energy. The aim of this study is synthesis, identification and characterization of particular oxalate hydrate phase synthesized with calcium salts (chloride, nitrate and sulphate). The effects of grinding speed and reaction duration regarding the time of synthesis were investigated. Structural and thermal sample properties were studied by FTIR spectroscopy and thermogravimetric analysis (TGA). Morphologic characteristics of calcium oxalate and size distribution were measured by optical microscopy and dynamic light scattering (DLS)

Sol-gel synthesis of complex metal oxides with double and triple perovskite-type structure

Perovskit je naziv za porodicu spojeva kristalne strukture čija je opća formula ABX3 gdje je A kation većeg ionskog promjera, B kation manjeg ionskog promjera, a X halogenidni anion ili kisik. U ovome diplomskom radu citratnom dvostupanjskom sol – gel metodom sintetizirani su sloţeni metalni oksidi perovskitne strukture $Sr_{3}Co_{2}TeO_{9}$, $Ba_{3}Co_{2}TeO_{9}$, $Sr_{3}NiTeO_{6}$ te $Ba_{2}NiTeO_{6}$. Nakon prvostupanjskog miješanja prekursora i kompleksacije citratnom kiselinom, u drugom koraku su osušeni uzorci kalcinirani pri 600 ˚C i 1000 ˚C u peći u struji zraka s temperaturom zagrijavanja 2 ˚C/min. Uzorci su karakterizirani cikličkom voltametrijom, infracrvenom spektroskopijom (FT – IR), termogravimetrijskom analizom (TGA), rentgenskom difrakcijom na prahu (PXRD) te su im odreĎena magnetska svojstva SQUID mjerenjima. UtvrĎeno je da su sintetizirani spojevi visoke čistoće te da su veličine kristalita male unatoč visokim temperaturama kalciniranja. $Sr_{3}NiTeO_{6}$ i $Ba_{2}NiTeO_{6}$ pokazuju antiferomagnetska svojstva.Perovskite is the name for a family of compounds with crystal structure of the general formula ABX3 where A is a cation of a larger ionic radius, B is a cation of a smaller ionic radius and X stands for halide or oxide anion. In this diploma thesis, complex metal oxides of perovskite type crystal structure $Sr_{3}Co_{2}TeO_{9}$, $Ba_{3}Co_{2}TeO_{9}$, $Sr_{3}NiTeO_{6}$ and $Ba_{2}NiTeO_{6}$ were synthesized by the citrate sol - gel route. Dried samples were calcined at 600 °C and 1000 °C in a furnace with air flow and at a temperature rate of 2 °C per minute. Samples were characterized by the cyclic voltammetry, infrared spectroscopy (FT –IR), thermogravimetric analysis (TGA), Powder X – ray diffraction (PXRD) while magnetic ground state has been determined using SQUID measurement. Obtained results have revealed that synthesized materials are of high purity and their average crystallite size has remained in nanometer range despite the high calcination temperatures. $Sr_{3}NiTeO_{6}$ and $Ba_{2}NiTeO_{6}$ posses antiferromagnetic properties

Micromechanical analysis of fatigue and crack growth in carbon-fiber epoxy composites based on mechanical testing

The paper presents static and dynamic tests of carbon/epoxy composite materials with fiber orientation at 0 degrees/90 degrees and +/- 45 degrees. The main tensile properties were determined as a basis for subsequent dynamic tests, in which permanent dynamic strength, crack growth, and crack growth rate in the material due to the action of fatigue load were assessed. Comparisons were made regarding the structure of the tested specimens. Samples were obtained from prepregs with a specific density of 1600 kg/m(3). The tests were performed at room temperature. Scanning electron microscopy (SEM) was used to analyze the damage in the material during these tests, the mechanisms of their further damage progression and, the impact on the growth and growth rate of the initial crack in the material. The analysis of numerical results and micromechanical analysis confirmed the dominant role of the reinforcing structural element in the material in all performed tests. The obtained results are of great importance in the application of composite materials of such structures under different operating conditions and load regimes