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1

Nitrogen removal and sludge reduction in anoxic-aerobic sequencing batch reactor with alkaline-H2O2 disintegration

Gürtekin Engin

Ecological Chemistry and Engineering. S

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2022

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Vol. 29, nr 4

511--523

EN

In this study, alkaline-H2O2 sludge disintegration was combined with anoxic-aerobic sequencing batch reactor (SBR). The carbon obtained by alkaline-H2O2 sludge disintegration was used in the denitrification process and sludge reduction was achieved in the SBR process. In the SBR process, a 9 % increase in nitrogen removal efficiency was achieved with the improvement in the denitrification process. A sludge reduction efficiency of 43 % was obtained in the SBR process with alkaline-H2O2 sludge disintegration. A synergistic effect was obtained in the combination of alkaline and H2O2 methods and the sludge reduction increased by 8 %. By combining sludge disintegration into the SBR process, it is possible to reduce the amount of sludge formed, which is an important environmental problem, and to provide carbon source for the denitrification process.

2

Static and Dynamic Mechanical Properties of Cotton/Epoxy Green Composites

Koyuncu M., Karahan M., Karahan N., Shaker K., Nawab Y.

Fibres & Textiles in Eastern Europe

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2016

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Vol. 24, no. 4 (118)

105--111

EN

A study on the effect of alkaline treatment on the mechanical properties of cotton fabric reinforced epoxy composites is presented in this paper. One hour treatment of cotton fabric was performed using three different concentrations of sodium hydroxide (NaOH) solution. 1% NaOH treated fabric reinforced composites exhibited maximum improvement in tensile strength. It was concluded that the said NaOH concentration improves interfacial adhesion between the cotton fabric and epoxy resin. Moreover the morphology of the fracture surface, evaluated by scanning electron microscopy (SEM), indicated that surface treatment can yield better adhesion between the fabric and matrix, demonstrating the effectiveness of the treatment. The dynamic mechanical analysis (DMA) results revealed that alkali treated (1% and 3% NaOH) fabric composites exhibit higher storage moduli and glass transition temperature (Tg) values as compared to the untreated fabric composites. However, for all the composite specimens, the storage modulus decreased with increasing temperature (25 - 100 °C). Tg values of 50.9, 56.7, 52.8 and 37.7 °C were recorded for the untreated and (1%, 3% and 5%) treated composites, respectively. The tan δ values decreased for all the composites with increasing temperature, indicating enhanced interactions between the polymer matrix and fabric reinforcement.

PL

Badano wpływ obróbki alkalicznej na mechaniczne właściwości tkanin bawełnianych wzmacniających kompozyty epoksydowe. Stosowano jednogodzinną obróbkę tkanin bawełnianych przy stosowaniu trzech różnych stężeń NaOH. Stwierdzono, że tkaniny poddane działaniu 1% NaOH wykazują najlepsze właściwości biorąc pod uwagę wytrzymałość na rozciąganie. Stwierdzono, że obróbka alkaliczna polepsza międzyfazową adhezję pomiędzy bawełnianą tkaniną i żywicą epoksydową. Oprócz tego stwierdzono, badając morfologię przełomów za pomocą SEM, że obróbka powierzchniowa pozwala na uzyskanie lepszej adhezji pomiędzy tkaniną a matrycą epoksydową. Stwierdzono również zmiany składowej rzeczywistej modułu zespolonego oraz wartości temperatury i przemiany szklistej. Ze wzrostem temperatury zmienia się również tan δ dla wszystkich kompozytów potwierdzając polepszającą się interakcję pomiędzy matrycą polimerową i włóknistym wzmocnieniem.

3

The petrogenesis of late Precambrian felsic alkaline magmatism in south Sinai, Egypt

Azer M.

Acta Geologica Polonica

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2006

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Vol. 56, no. 4

463-484

EN

Alkaline felsic magmatism represents the final phase of the late Precambrian acid magmatism in south Sinai. The studied felsic suites occur as dyke-like intrusions, exhibit features characteristic of A-type granites. There were two main cycles of magmatic activity separated by a period of magmatic quiescence, which led to a composition gap between them. The earlier cycle includes quartz syenite that represents the precursor of the A-type granite series in south Sinai, whereas the second cycle includes more felsic volcanic-subvolcanic intrusive complexes. Intrusion of the two cycles was controlled by the preexisting structure and individual igneous bodies were emplaced in an extensional tectonic regime during a phase of fracturing and uplift at the end of the Pan-African orogeny. The high variability in geochemical signature of A-type magmas in south Sinai suggests a variety of petrologic processes and reservoirs which reflects the participation of an intraplate mantle reservoir and enolved continental crust. Kenrichment in the rhyolite is a primary feature and attributed to the effect of volatiles which accumulated in the upper part of the magma chamber. In general, A-type magmas in south Sinai can be differentiated according to their magma source and tectonic setting into (1) non-primitive A-type magma (ANP) and (2) primitive A-type magma (AP). The non-primitive A-type magma is commonly known in Sinai as Iqna granite, which belongs to the highly fractionated, late- to post-orogenic, calc-alkaline I-type granites. The primitive A-type magma shows within-plate geochemical characteristics and was emplaced in an anorogenic setting. It is distinguished further into: (i) a magma having characteristics indicative of OIB-mantle contribution (A[1]), and (ii) magma derived from crustal sources (A[2]).