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Showing 1 to 6 of 6 (0.028 seconds)Spelling suggestions: "subject:"tassement""
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Zvinowanda, CM, Okonkwo, GO, Sekhula, MM, Agyei, NA, Sadiku, R 10 March 2008 (has links)
Abstract
In this study, the removal of Pb(II) from aqueous solutions by tassel powder was studied and optimised.
Batch experimentswere conducted on simulated solutions using tassel powder adsorbent and the effects
of contact time, pH and concentration on the extent of Pb (II) removalwas studied. Equilibrium and kinetic
models for Pb(II) sorption were developed by considering the effect of contact time and concentration
at optimum pH 4 and fixed temperature(25 ◦C). The Freundlich model was found to describe the sorption
energetics of Pb(II) on tassel more fully than the Langmuir. A maximum Pb(II) loading capacity of
333.3 mg/g on tassel was obtained. The adsorption process could be well described by both the Langmuir
and Freundlich isotherms with R2 values of 0.957 and 0.972, respectively. The kinetic parameters
were obtained by fitting data fromthe effect of contact time on adsorption capacity into the pseudo-first,
pseudo-second-order and intra-particle diffusion equations. The kinetics of Pb(II) on tassel surface was
well defined using linearity coefficients (R2) by pseudo-second-order (0.999), followed by pseudo-firstorder
(0.795) and lastly intra-particle diffusion (0.6056), respectively. The developed method was then
applied to environmental samples taken fromborehole waters contaminated with mine wastewater. The
removal of Pb (ND-100%), Se (100%), Sr (5.41–59.0%),U(100%) and V (46.1–100%)was attained using tassel.
The uptake of the metals from environmental samples was dependent on pH, ionic strength and levels of
other competing species.
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| 2 |
Application of maize tassel for the removal of Pb, Se, Sr, U and V from borehole water contaminated with mine wastewater in the presence of alkaline metalsZvinowanda, CM, Okonkwo, JO, Sekhula, MM, Agyei, NM, Sadiku, R 25 August 2008 (has links)
A b s t r a c t
In this study, the removal of Pb(II) from aqueous solutions by tassel powder was studied and optimised.
Batch experimentswere conducted on simulated solutions using tassel powder adsorbent and the effects
of contact time, pH and concentration on the extent of Pb (II) removalwas studied. Equilibrium and kinetic
models for Pb(II) sorption were developed by considering the effect of contact time and concentration
at optimum pH 4 and fixed temperature(25 ◦C). The Freundlich model was found to describe the sorption
energetics of Pb(II) on tassel more fully than the Langmuir. A maximum Pb(II) loading capacity of
333.3 mg/g on tassel was obtained. The adsorption process could be well described by both the Langmuir
and Freundlich isotherms with R2 values of 0.957 and 0.972, respectively. The kinetic parameters
were obtained by fitting data fromthe effect of contact time on adsorption capacity into the pseudo-first,
pseudo-second-order and intra-particle diffusion equations. The kinetics of Pb(II) on tassel surface was
well defined using linearity coefficients (R2) by pseudo-second-order (0.999), followed by pseudo-firstorder
(0.795) and lastly intra-particle diffusion (0.6056), respectively. The developed method was then
applied to environmental samples taken fromborehole waters contaminated with mine wastewater. The
removal of Pb (ND-100%), Se (100%), Sr (5.41–59.0%),U(100%) and V (46.1–100%)was attained using tassel.
The uptake of the metals from environmental samples was dependent on pH, ionic strength and levels of
other competing species.
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| 3 |
Characterization of sterile tassel silky earl: A Homeotic B-Class Gene Involved in Specification of Floral Organ Identity In Zea maysWilliams, Steven Keith 12 December 2012 (has links) (PDF)
Specification of floral organ identity in angiosperm flowers is accomplished by the coordinated activity of A-, B-, C-, and E-class MADS-box genes. In the eudicots, B-class genes specify petal and stamen identity. This eudicot B-class function depends on the simultaneous expression of genes from two paralogous B-class lineages (the DEFICIENS/APETALA3 lineage and the GLOBOSA/PISTILLATA lineage). Proteins produced by genes from these two lineages interact as obligate heterodimers and together regulate the transcription of various downstream targets. These obligate heterodimers also positively regulate the transcription of the B-class genes themselves, thereby mediating a unique B-class autoregulatory feedback loop. There is compelling evidence that B-class function at the phenotypic and molecular level is highly conserved among the eudicots. The degree to which B-class homeotic function, obligate heterodimerization, and autoregulation are conserved in non-eudicot, however, remains a topic of debate. Here we describe loss of function in Sterile tassel silky ear1 (Sts1) a maize ortholog of GLOBOSA/PISTILLATA formerly known as Zmm16. Mutation in Sts1 results in homeotic transformation of lodicules and stamens into bract-like organs in male inflorescences. Female inflorescences are affected in a similar manner. Stamens in these inflorescences are, however, transformed into carpels instead of into bract-like organs. This mutant phenotype suggests that Sts1 has a B-class homeotic function. Using qRT-PCR we also demonstrate that Sts1 participates in positive transcriptional regulation of all of the maize B-class genes. These findings suggest a high degree of B-class functional conservation between the monocots and the eudicots. Analysis of tasselseed1/sts1 and grassy tillers1/sts1 double mutants suggests that maize B-class genes also play a role in the sex determination process.
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From Diderot to Software Bot: The Evolution of Encyclopedias in Historical StudyChamberlain, Ryan 26 May 2023 (has links)
No description available.
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Možnosti využití textilních materiálů v předmětu Praktické činnosti na 1. stupni ZŠ / Possibilities of Textile Materials in Practical Activities Subject in Primary SchoolDOLANOVÁ, Klára January 2015 (has links)
The thesis topic is "Possibilities of Textile Materials in Practical Activities Subject in Primary School". The theoretical part is focused on the historical origin and evolution of textiles, summary of textile techniques, sorting and its use mainly with pupils in the primary school. It also deals with project based learning and conceptions, objects and competences of a pupil in the primary school in technical education in czech system of Framework Educational Programme for Elementary Education. In the practical part there are designed textile techniques that are processed into the original teaching projects. The functionality of the project was detected by using questionnaires for teachers of primary school. Some of the projects were realized in teaching in the 2nd, 3rd and 4th year of the primary school.
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An Analysis of Grain Corn Nutritional Supplements and Relative Maturity in MississippiWhittenton, Joseph Bryan 04 May 2018 (has links)
A review of available corn relative maturity groups in Mississippi shows a limited range of maturity groups in use. Research focusing on expanding the range of maturity groups was conducted in MS in 2015 and 2016. Along with expanded maturity groups, treatments of fertilizer (10-34-0), foliar zinc, and a plant hormone blend were studied to shorten the growing season. Four site years in MS were studied to determine optimal plant maturity group and treatment for length of season. The results showed decreased yield of 0.09-0.15 Mg ha-1 (1.5-2.3 bu ac-1) for each day of decreasing relative maturity in three of four site years. The addition of starter fertilizer increased vegetative growth stage, plant height V5 and V7, SPAD values at V5, and significantly decreases days to tassel and silking reproductive growth stages but did not affect yield.
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