“Trap-dams”: Artificial Subsurface Storage of Water
To secure and increase the availability of clean drinking water in arid and semi-arid regions of the world, construction of sediment filled dams for artificial subsurface storage of water could provide very cost efficient solutions.
Appropriate Technology for Artificial Aquifers
This paper suggests a labor-intensive water-supply technique that may be classified as appropriate technology in that it conserves energy and capital (scarce inputs in developing countries) and utilizes labor (an abundant input in these same countries). The problem of collecting rain during the wet season for use during the rest of the year is compounded by evaporation and infiltration losses. Lining a shaped reservoir in a slough or gully can eliminate the infiltration losses; filling the same reservoir with uniform sand and a gravel mulch can greatly reduce the evaporation losses. Thus one creates an artificial aquifer with an appropriate technology which can supply filtered water under gravity flow with minimal maintenance.
Novel method for the determination of the methoxyl content in lignin by headspace gas chromatography.
The paper reports on a headspace gas chromatographic (HS-GC) method for the determination of methoxyl in lignin. The method involves the quantitive cleavage of methoxyl with hydroiodic acid (HI) to form methyl iodide in a closed headspace sample vial at 130 °C for 30 min. After HI has been added, the sample is neutralized by injecting a sodium hydroxide solution; the methyl iodide in the vial was determined by HS-GC using a flame ionization detector. The results showed that the method has an excellent measurement precision (RSD < 0.69%) and accuracy (RSD < 3.5%) for the quantification of methoxyl content in lignin. The present method is simple and accurate and can be used for the efficient determination of methoxy1 content in lignin and related materials.