7 research outputs found
Functional hyaluronic acid conjugates based on natural polyphenols exhibit antioxidant, adhesive, gelation, and self-healing properties
No full textOverview of Polyethylene Based Multi-layered Geomembrane Through Blown Extrusion Process
No full textGeomembranes are low-permeable liners used to control the molecular migration in many proven applications. Landfills is most common application in the field of civil and environmental engineering. Geomembrane is the main component in lining system which works as hydraulic barrier. The polyolefins are the basic materials of liner and more commonly polypropylene and polyethylene are preferred. Commercial manufacturing process involves extrusion techniques viz cast extrusion and blown extrusion process. The individual process is designed for multiple layered structures which are then coextruded to lead into a single liner. Typical structure comprises, high to low-density polyethylene (PE) resin, processing aids, stabilisers to retard the degradation through ultra-violet rays, photo-oxidation, and thermal oxidation. The stabilizer is usually used in smaller dosses to avoid degradations which includes, 2 to 3% carbon-black (CB), 0.5 to 1% antioxidants (AO), and plasticizing additives to introduce the flexibility. During the process, components are homogenised in specially designed screws of feeding and mixing zones. The formulated melt is co-extruded through specially designed die of multi-layered structures. The subsequent melt enters in circular die with a certain pressure which leads to bubbled shaped films. The variation in the surface morphology layer structure and layer number are the important technical aspects to alter the required end application. Finally, manufactured geomembrane is qualified as per the international specifications which are governed by geosynthetic research institute (GSI/GRI)
Antioxidant and ion-induced gelation functions of pectins enabled by polyphenol conjugation
No full text
A review of groundwater vulnerability assessment in Kenya
No full textGroundwater represents 95% of the world’s unfrozen freshwater. The use of groundwater has significantly increased over the past 50 years and is expected to rise in future due to its high reliability during drought seasons, good quality, generally modest development costs and continuous depletion of surface water. Groundwater pollution is becoming a major threat to fresh groundwater availability and sustainability. The deteriorating groundwater quality and increasing contamination poses detrimental risk to human health and ecosystem in many ways, thereby necessitating the need to study the groundwater vulnerability assessment as a preventive strategy to protect the groundwater from surface pollution. The concept of groundwater vulnerability assessment is dated back in 1970s and applied in many developed countries as an environmental tool used for proper land use planning and decision making without jeopardizing groundwater quality. This paper is a detail review of available literature on the study of groundwater vulnerability assessment in Kenya. The paper revealed that, the vulnerability assessment concept has not been applied as a mechanism to prevent groundwater pollution, hence rarely used in guiding land use planning in Kenya. This review brings to limelight the importance of groundwater vulnerability assessment in management and protection of groundwater resources in Kenya.
*Corresponding author; Email:[email protected] Mobile: 0710953283.
1. Soil, Water and Environmental Engineering Department Jomo Kenyatta University of Agriculture and Technology, Keny
