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1

Comparison between SEPs of CaCO3 and TiO2 in phosphor layer for better color uniformity and stable luminous flux of WLEDs with 7,000 K

Le Phan Xuan, Trang Tran Thanh, Anh Nguyen Doan Quoc, Lee Hsiao-Yi, Tho Le Van

Materials Science Poland

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2022

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Vol. 40, No. 1

1--8

EN

CaCO3 and TiO2 are proposed in this study as particles for scattering enhancement (SEPs) of phosphor-converted white light-emitting diodes (pc-WLEDs). The use of these two SEPs for scattering improvement enables boosting of the color homogeneity of the WLED devices. Each SEP is mixed with YAG:Ce3+ and silicone composition to examine their optical influences and performances on the high-power WLED packages with 7,000 K color temperature (CT). Miescattering theory is applied to calculate and investigate the scattering elements - scattering coefficients, anisotropic scattering, the reduced scattering, and scattering amplitudes - at the wavelengths of 450 nm and 550 nm. The results exhibit that TiO2and CaCO3 considerably promote higher color uniformity and color-deviated reduction, respectively. The obtained results could be primarily attributed to the significant improvement in the scattering properties of the structure. Additionally, the effects of the presented scattering enhancement on luminous efficiency are displayed. The reduction in lumen output is observed to have a close connection with the concentration and particle size of TiO2and CaCO3, which means that control must be exercised over these factors when utilizing these SEPs for WLED fabrication.

2

The Effects of Calcium Carbonate Filler on HDPE Pipe

Kherici Samira, Benouali Djillali, Nouredine Chekhar

Advances in Science and Technology. Research Journal

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2022

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Vol. 16, no 3

213--218

EN

The objective of this work is the preparation and the characterization of high density polyethylene /calcium carbonate (HDPE/CaCO3) composites. Polyethylene composites, containing 10-35 wt. % of CaCO3 and HDPE with MFI (Melt Flow index) (0.550 g/10mn) were prepared with co-extrusion process using extruder type Cincinati 90D. Thermal and mechanical studies were made in order to determine the parameters for obtaining a material (corrugated pipe) with optimal properties. The composite viscosity increased with filler content, suggesting the formation of filler agglomerates. Thermal analysis shows that addition of 30 % CaCO3 increased the thermal stability of HDPE around 32°C, decreasing the processing temperature of composites in 15°C. Regarding to the mechanical tests, the ring stiffness of the composites decreased with the addition of CaCO3. According to the obtained results, we suggest that HDPE/CaCO3 composites could be used in the pipe production where tensile strengths higher than 25 MPa are not required and for service temperatures between 30°C and 70°C.

3

The mechanism of CaCO3 in the gas-based direct reduction of a high-phosphorus oolitic iron ore

Wu Shichao, Li Zhengyao, Sun Tichang, Kou Jue, Xu Chengyan

Physicochemical Problems of Mineral Processing

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2021

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Vol. 57, iss. 4

117--124

EN

Gas-based direct reduction and magnetic separation process was applied in treating a high-phosphorus oolitic iron ore, of which phosphorus mainly occured as Fe3PO7 and apatite. The mechanism of CaCO3 was investigated using XRD, SEM-EDS, and mineral phase analysis. Results showed that when no CaCO3 was added, most of the iron minerals were reduced to metallic iron, while Fe3PO7 was reduced to elemental phosphorus and mixed with the metallic iron particles. When a small amount of CaCO3 was added, CaCO3 preferentially reacted with SiO2, Al2O3 and other components, preventing them from reacting with FeO and resulting in the increase of iron recovery. When the amount of CaCO3 reached 25%, apatite was produced from the reaction of CaO and Fe3PO7, which could be later removed by grinding and magnetic separation.

4

Thermal gravimetric analysis of glass fiber reinforced composite for understanding the impact of copper oxide in relation to titanium oxide filler particles

Alam Shahinoor, Chowdhury Mohammad Asaduzzaman

Composites Theory and Practice

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2021

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R. 21, nr 1-2

12--21

EN

In this work, the composite samples required to investigate their thermal properties were fabricated employing the conventional hand lay-up technique, followed by a light compression molding process. A fixed weight of plain woven glass fiber and epoxy with four different types of fillers as calcium carbonate (CaCO3), aluminum oxide (Al2O3), magnesium oxide (MgO) and titanium oxide (TiO2) or copper oxide (CuO) of different weights (5, 10 and 15 g) were studied. According to thermal gravimetric analysis (TGA), it was observed that the melting point (Tm) and glass-transition temperature (Tg) are affected by the presence of CuO and TiO2, which indicate the degree of composite crystallinity established by the stronger interfacial interaction by the CuO than that of the TiO2 particles and the amorphous region of the chain. These studies were supported by examination of the surface morphology of the composites by means of scanning electron microscopy (SEM).

5

Podstawy i możliwości wykorzystania procesu biomineralizacji węglanu wapnia

Krajewska Barbara, Raczak Kinga

Ochrona Środowiska

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2019

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Vol. 41, nr 1

31--37

PL

Węglan wapnia CaCO3 jest substancją szeroko rozpowszechnioną w przyrodzie i znajduje liczne zastosowania praktyczne. W przyrodzie jego biomineralizacja jest między innymi wynikiem procesów strącania indukowanych mikrobiologicznie. Jednym z nich jest strącanie indukowane przez bakterie ureolityczne. Proces ten, jeśli prowadzony biomimetycznie, zachodzi w łagodnych warunkach i co ważne, może być zastosowany w warunkach polowych in situ. W ten sposób stanowi on ekoprzyjazną i energooszczędną technikę do wykorzystania jako ekologiczna alternatywa dla obecnie stosowanych technik w wielorakich obszarach inżynieryjnych. W obszarach tych wytrącany CaCO3 spełnia rolę czynnika remediacyjnego i cementującego, na przykład w celu (1) oczyszczania wód z jonów metali toksycznych i radionuklidów, (2) wzmacniania i konsolidacji gruntu i piasku, (3) uszczelniania formacji geologicznych, (4) naprawy obiektów budowlanych i (5) ochrony powierzchni tych obiektów warstwami ochronnymi. Choć stosowana z powodzeniem w sektorze ochrony i restauracji budowli historycznych, technika ta pozostaje ciągle na etapie badań i procesów optymalizacyjnych. By stać się w pełni niezawodną i ekonomiczną techniką wymaga ona dalszych badań, których zadaniem jest rozwiązanie ograniczeń i parametryczna optymalizacja, oraz testy w pełnowymiarowych eksperymentach polowych. Jest to zadanie interdyscyplinarne dla inżynierów budownictwa, geologów, chemików, mikrobiologów i konserwatorów zabytków, którego efektem będzie wprowadzenie tej ekoprzyjaznej i innowacyjnej techniki na rynek inżynierski do wykorzystania w inżynierii środowiska i lądowej, geotechnice i konserwacji zabytków. W kontekście ekopotencjału i innowacyjności tej techniki, w niniejszym artykule przedstawiono jej podstawy, obszary jej zastosowań oraz zalety i ograniczenia.

EN

Calcium carbonate (CaCO3) is a substance widespread in nature and used in numerous practical applications. In nature, its biomineralization relies, among others, on microbiologically induced precipitation processes. One of such processes is precipitation induced by ureolytic bacteria. If performed in a biomimetic manner, the process is carried out under mild conditions and, most importantly, can be employed in field applications in situ. Therefore, the process constitutes an eco-friendly and energy-saving technique to be used as an ecological alternative to conventional techniques in a variety of engineering fields. In these fields, CaCO3 serves as a remediating and cementing agent, for instance to (1) clean waste- and groundwater from toxic metals and radionuclides, (2) strengthen and consolidate soil and sand, (3) seal geological formations to enhance oil recovery and geologic CO2 sequestration, (4) repair stone and concrete structures, and (5) cover surfaces of these structures with protective layers. Although already in use in the sector of protection and renovation of stone monuments, to date the technique has remained mostly under research and optimization. To become fully implementable as a reliable and economically viable technique, it still requires further research in order to address its limitations, focus on parametrical optimization, up-scaling and life-size field experiments. All these, in an interdisciplinary effort of geologists, microbiologists, chemists, civil engineers and conservators of historic monuments, will move this eco-friendly and innovative branch of engineering from laboratory to field applications in the environmental and civil engineering, geotechnology and conservation of historic buildings. Given its eco-potential and innovativeness, in this study the principles of the technique, advantages, possible applications and challenges are reviewed.

6

Wpływ warunków strącania na właściwości CaCO3 otrzymanego z płynu podestylacyjnego i ługu pofiltracyjnego z metody Solvaya w temperaturze 313 K

Białowicz K., Trypuć M.

Przemysł Chemiczny

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2011

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T. 90, nr 8

1604-1607

7

Shielding effect of nanoadditives against UV radiation in polypropylene fibres

Dulíková M., Strecká Z., Ujhelyiová A., Legéň J., Bugaj P.

Fibres & Textiles in Eastern Europe

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2010

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Vol. 18, no. 5 (82)

55--58

EN

The shielding effect of a nanoadditive (CaCO3) against ultraviolet radiation (UVR) in polypropylene fibres was investigated. Unmodified and modified polypropylene (PP) fibres with different contents of the nanoadditive were prepared. It was investigated how the modified polypropylene fibres affect the transmission of UVR. The impact of nanoadditive treatment, the amount of nanoadditive in the fibre, and the fibre preparation was studied from the point of view of barrier properties against UVR. The different parameters which influence the transmission of UVR through fibres were observed. The thermal characteristics were evaluated by DSC measurement. The mechanical properties were also measured.

PL

Zbadano ochronę przed promieniowaniem ultrafioletowym (UVR) przez włókna polipropylenowe z nanododatkiem (CaCO3). Przygotowano niemodyfikowane i modyfikowane włókna polipropylenowe z różną zawartością nanododatku. Zbadano, jak modyfikacja włókien polipropylenowych wpływa na transmisję promieniowania UVR. Oceniono wpływ obróbki i ilości nanododatku we włóknie z punktu widzenia właściwości ochronnych przed promieniowaniem UVR. Określono różne parametry, które wpływają na transmisję UVR przez włókna. Za pomocą pomiaru DSC wyznaczono charakterystyki termiczne a poza tym dokonano oceny właściwości mechanicznych włókien.

8

Effect of atomization degree of CaCO3 absorption suspension in spray absorber on its height

Głomba M.

Environment Protection Engineering

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2008

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Vol. 34, nr 4

177-186

EN

The paper provides the analysis of the effect of greater atomizing degree of absorption slurry on reducing the height of absorption zone in the absorber, hence the height of the whole absorber, and on reduction of power demand for pumps used to lift the absorption slurry from retention reservoir to atomizers.

PL

Zanalizowano wpływ zwiększenia stopnia rozpylenia zawiesiny absorpcyjnej na zmniejszenie wysokości strefy absorpcji w absorberze, a tym samym całego absorbera, oraz na ograniczenie składowej zapotrzebowania mocy pomp na podnoszenie zawiesiny absorpcyjnej ze zbiornika retencyjnego do rozpylaczy

9

Effectiveness of peat as a sorbent of excessive copper contents in light soil depending on the degree of its contamination

Wróbel S., Nowak K.

Chemia i Inżynieria Ekologiczna

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2007

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Vol. 14, nr 5-6

601-608

EN

The research aimed at determining the effectiveness of peat as a sorbent of excessive copper content in light soil contaminated with that metal. It was carried out in two-factor pot experiments: first factor (A) - degree of soil contamination - 0, 75, 150, 300 and 450 mg Cu kg-'; second factor (B) - remediation of soil, ie variants of applying peat and CaCO3, n = 6. No remediation would practically exclude the possibility of growing white mustard at already 150 mg Cu kg-' level of soil contamination. This situation is expressed well by negative correlations with high coefficients (a= 0.001) between the mustard yields and the content of available copper in soil (r = -0.766) and total copper in biomass (r = -0.759). Peat applied separately immobilized excessive copper in soil to higher degree than liming. The highest effectiveness of remediation was obtained when 3% of peat together with CaCO3 in the dose acc. to 1 Hh were introduced into the soil.

PL

Celem badań była ocena skuteczności działania torfu jako sorbentu nadmiarów miedzi z gleby lekkiej zanieczyszczonej tym metalem. Badania przeprowadzono w dwuczynnikowych doświadczeniach wazonowych: czynnik pierwszy (A, n = 5) - stopień zanieczyszczenia gleby - 0, 75, 150, 300 i 450 mg Cu kg-' gleby; czynnik drugi (B, n = 6) - remediacja gleby, tj. warianty stosowania torfu i CaCO3. Brak remediacji praktycznie wykluczał możliwość uprawy gorczycy białej już przy zanieczyszczenia gleby wynoszącym 150 mg Cu kg-'. Sytuację tę dobrze oddają ujemne korelacje (alfa<=0,001) o dużych współczynnikach, pomiędzy poziomem plonów gorczycy a zawartością miedzi przyswajalnej w glebie (r = -0,766) i miedzi ogólnej w biomasie (r = -0,759). Stosowanie torfu oddzielnie było czynnikiem w większym stopniu immobilizującym nadmiary miedzi w glebie niż wapnowanie. Największą skuteczność remediacji uzyskano, wprowadzając do gleby 3% torfu łącznie z CaCO3 w dawce wg 1 Hh.

10

A study on thermal behaviour of HDPE/CaCO3 nanocomposites

Zebarjad S. M., Sajjadi S. A., Tahani M., Lazzeri A.

Journal of Achievements in Materials and Manufacturing Engineering

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2006

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Vol. 17, nr 1-2

173--176

EN

Purpose: In order to improve physical and mechanical properties of high density polyethylene (HDPE) addition of filler, rigid particles and even elastomer to HDPE is very common. One of the most important filler which is added to it is nano size calcium carbonate (CaCO3). To avoid agglomeration of nano size calcium carbonate addition of fatty acids such as stearic acid is very common. Design/methodology/approach: In the current study, nanocomposites with 10vol% nano size calcium carbonate were prepared. To investigate the role of stearic acid on nanocomposite behaviour, nanoparticles were coated at different stearic acid content. Thermal behaviour of high density polyethylene and its nanocomposites reinforced with both uncoated and coated calcium carbonate were investigated. For this purpose differential scanning calorimetry (DSC) test was used. Findings: The results of DSC test showed that addition of 10vol% calcium carbonate to HDPE causes a slightly rise in its melting point but stearic acid content has no significant effect on the melting temperature of HDPE nanocomposites. Research limitations/implications: Agglomeration of nanosized calcium carbonate during sample preparation was the major research limitation. Originality/value: Crystallization temperature of HDPE with addition of 10vol% calcium carbonate increases, while addition of stearic acid causes to decrease it. Both stearic acid content and 10vol% calcium carbonate have no significant effect on crystallinity index of HDPE.