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Leaching of manganese ores using corncob as reductant in H2SO4 solution

Ali S., Iqbal Y., Farooq U., Ahmad S.

Physicochemical Problems of Mineral Processing

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2016

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Vol. 52, iss. 1

56--65

EN

In this study, corncob was used as reductant for sulfuric acid leaching of manganese ore from Daweezi, Upper Mohmand Agency, Pakistan. X-ray diffraction of representative powdered samples revealed the presence of manganese silicate MnSiO(SiO4), calcite (CaCO3), and -quartz (SiO2). X-ray diffraction and energy dispersive spectroscopy analyses indicated that the examined manganese ore was siliceous in nature. Three process parameters were investigated in the present study including the particle size of the ore, leaching temperature, and amount of corncob. Manganese extraction of 92.48 wt% was achieved for a leaching time of 60 min at 90 oC using 1.9 mol/dm3 H2SO4 concentration and 4 g of corncob. The present results demonstrated that corncob is a low cost, renewable, and non-hazardous reducing agent for manganese leaching under mild acid conditions in comparison to the other available reagents.

2

Efficient data generation for the testing of real-time multiprocessor scheduling algorithms

Shehzad M. N, Déplanche A. M, Trinquet Y, Farooq U

Przegląd Elektrotechniczny

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2014

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R. 90, nr 9

136-139

EN

In conducting the performance evaluation tests of real-time multiprocessor scheduling algorithms, synthetic input data is mandatory for obtaining reliable results and to draw strong conclusions. The results of the statistical evaluation highly depend on the data chosen for the experimentation. The data generation process is required to be efficient while the resultant data should comply with the user requirements. This article discusses two established data generation techniques used in the literature, explains their advantages and disadvantages, and finally proposes few extensions in one of the techniques, which is considered quite efficient, to be made compatible with discrete time simulator.

PL

W artykule przedyskutowano dwie techniki generacji danych w multiprocesorze czasu rzeczywistego. Zaproponowano modyfikacje algorytmu Stafforda.

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Tanacetamide C : One New Ceramide from Tanacetum artemisioides

Hussain J., Ahmad V., Hussain H, Hassan Z., Khan A., Farooq U

Polish Journal of Chemistry

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2005

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Vol. 79 / nr 6

967-971

EN

A reinvestigation with a modified extraction procedure of Tanacetum artemisioides resulted in the isolation and structure elucidation of one new ceramide named tanacetamide C and assigned structure 2R,3'R,3R,4'S,6R,4E-N-[3',4'-dihydroxydodecanoyl]- 2-amino-4-nonacosene-1,3,6-triol (1). In addition 5,4'-dihydroxy-3,6,7-trimethoxyflavone (2), 5-hydroxy-3,6,7,4'-tetramethoxy flavone (3), leukodin (4) were also isolated for the first time from this species. The structure elucidation of the isolated new compound was based primarily on 1D and 2D NMR analysis, including COSY, HMQC, HMBC correlations.

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Limbatolide F and G: Two New trans-Clerodane Diterpenoids from Otostegia limbata

Farooq U., Khan A., Ahmad V., Kousar F., Iqbal S.

Polish Journal of Chemistry

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2005

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Vol. 79 / nr 11

1757-1762

EN

Two new trans-clerodane diterpenoids pro vi sion ally named as limbatolide F (1) and limbatolide G (2) were isolated from the chloroform extract of Otostegia limbata. Both compounds 1 and 2 have a unique feature of C-4/C-6 five membered a,b-un saturated lactone. The structures of these new compounds as well as their relative configurations were determined by 1D and 2D NMR techniques including COSY, HMQC, HMBC, NOESY and NOE experiments.