Botswana International University of Science and Technology

About: Botswana International University of Science and Technology is a education organization based out in Palapye, Botswana. It is known for research contribution in the topics: Thin film & Population. The organization has 546 authors who have published 1220 publications receiving 8403 citations.

Drought monitoring and analysis: Standardised Precipitation Evapotranspiration Index (SPEI) and Standardised Precipitation Index (SPI)

Abstract: Although rainfall is a major indicator of the availability of water, temperature is also an important factor that can influence the availability of water as it controls the rates of evapotranspiration. Parameters such as rainfall and temperature can be used as indicators of drought. These indicators are converted to drought indices which show the different characteristics of a drought. This study compares two different drought indices in the Kafue Basin located in northern Zambia, where most of the socioeconomic livelihoods are dependent on water. The Standardised Precipitation Index (SPI) depends on precipitation as the single input variable while the Standardised Precipitation Evapotranspiration Index (SPEI) is derived from precipitation and temperature in the form of a simple water balance. By comparing time series plots (1960–2015) of the two indices, both indices were able to pick up temporal variation of droughts. SPI and SPEI agreed (R > 0.5) on the direction of change but the effect on the drought condition was different. Compared to SPI, SPEI identified more droughts in the severe to moderate categories, with extended duration and increased intensity. On the other hand, SPI identified more droughts than SPEI under the extreme category, but with a shorter duration and reduced frequency of occurrence compared to the severe to moderate droughts. The results suggest that temperature variability plays an important role in characterising droughts. SPI is useful in that it only requires rainfall as input and especially where temperature data is missing. However, the use of SPI to characterise drought should be done with caution.

Environmental impact of food packaging materials: a review of contemporary development from conventional plastics to polylactic acid based materials

Abstract: Plastics have remained the material of choice, and after serving their intended purpose, a large proportion ends up in the environment where they persist for centuries. The packaging industry is the largest and growing consumer of synthetic plastics derived from fossil fuels. Food packaging plastics account for the bulk of plastic waste that are polluting the environment. Additionally, given the fact that petroleum reserves are finite and facing depletion, there is a need for the development of alternative materials that can serve the same purpose as conventional plastics. This paper reviews the function of packaging materials and highlights the future potential of the adoption of green materials. Biopolymers have emerged as promising green materials although they still have very low market uptake. Polylactic acid (PLA) has emerged as the most favoured bioplastic. However, it is limited by its high cost and some performance drawbacks. Blending with agricultural waste and natural fillers can result in green composites at low cost, low greenhouse gas emissions, and with improved performance for food packaging applications. The continent of Africa is proposed as a rich source of fibres and fillers that can be sustainably exploited to fabricate green composites in a bid to achieve a circular economy.