Evaluation of Sweetpotato Varieties for the Potential of Dual-Purpose in Different Agroecological Zones of Kenya

Dodecyltrimethylammonium bromide (DTAB)–modified and unmodified calcium bentonite were both used for the competitive adsorption of aromatics (xylene, ethylbenzene and toluene) and petroleum products (gasoline, dual purpose kerosene and diesel) from their aqueous solution. Infrared spectroscopy (IR) and expansion tests (adsorption capacity and Foster swelling) measurement were performed in order to evaluate the performance of the adsorbents. The Foster swelling index and adsorption capacity of the DTAB modified calcium bentonite in the organic solvents follow the trend: xylene > ethylbenzene > toluene > gasoline > dual purpose kerosene (DPK) > diesel > water. However, the adsorption capacity of the adsorbent in diesel outweighed the adsorption capacity in DPK at high concentration of DTAB indicating that diesel has higher affinity for high DTAB concentration than DPK. The percentage removal of the solvent is directly proportional to the concentration of DTAB used in modifying the bentonite as well as the contact time between the adsorbent and the solvent, hence modified calcium bentonite adsorbed a higher percentage of organic solvents than the unmodified calcium bentonite. The adsorption characteristics of both adsorbents improved remarkably after proper agitation of the organic solvents, the unmodified calcium bentonite however adsorbed more water than the modified bentonite. Data obtained from adsorption isotherm models confirms that Freundlich adsorption isotherm model was favored more than Langmuir adsorption isotherm model with the correlation factor (R2) of the former tending more towards unity. The adsorption of ethylbenzene using DTAB modified and unmodified calcium bentonites follow a pseudo second order kinetics mechanism, suggesting that the rate determining step of adsorption involves both the adsorbent and the organic solvent.

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Couple User Preferences in Dual Purpose Prevention Products

Case Medical Research ◽

10.31525/ct1-nct04023799 ◽

2019 ◽

Author(s):

Keyword(s):

User Preferences ◽

Dual Purpose

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Of Whales and Dugongs: Examining the Rise of Colonial Conservation as Development in Madagascar’s Marine History

Environment and History ◽

10.3197/096734019x15755402985622 ◽

2020 ◽

Author(s):

Merrill Baker-Médard

Keyword(s):

Conservation Policy ◽

Marine Conservation ◽

Colonial Period ◽

Marine Resources ◽

Current Conservation ◽

Dual Purpose ◽

Local Resource ◽

Conservation And Development ◽

The Way

This work explores how colonial marine conservation policy in Madagascar had the dual purpose of facilitating the expansion of capital and ‘civilising’ the way Malagasy fishers used marine resources. I analyse how the legacy of narratives that emerged to bolster state-led conservation intervention during the colonial period are still present in current conservation and development narratives, perpetuating in some cases the coloniser–colonised relationship between conservation organisations and local resource users. These findings indicate a need to revamp certain aspects of marine conservation legislation in Madagascar and the need for conservation organisations to explicitly acknowledge this history when working with local resource users in order to avoid reproducing historical injustices.

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