Antioxidant potential of common leafy vegetables in Bangladesh

Amount of polyphenols, flavonoids, anthocyanins in ethanol extracts and antioxidant activity of both ethanol and lipophilic extracts of common leafy vegetables in Bangladesh were compared. Among the 12 leafy vegetables, Ipomoea aquatica Forssk. showed the highest content of total polyphenols (38.9 mg gallic acid equivalent (GAE)/g extract) and flavonoids (23.2 mg (+)-catechin equivalent (CE)/g extract). Highest anthocyanins content was found in Amaranthus gangeticus L. (1.15 ?mol/g extract) followed by Pisum sativum L. (0.85 ?mol/g extract). Ethanol extracts of Brassica campestris L., Enhydra fluctuans Lour., I. aquatica, Lagenaria siceraria (Mol.) Standl. and P. sativum exhibited high DPPH free radical scavenging activity with IC50 of 104.2, 85.5, 26.9, 125 and 68.5 ?g/ml, respectively whereas for the same lipophilic pentane extracts of Basella alba L. showed the lowest (68.4 ?g/ml) IC50 followed by I. aquatica (70.4 ?g/ml), E. fluctuans (75.7 ?g/ml), L. siceraria (78.3 ?g/ml) and B. campestris (80.6 ?g/ml). I. aquatica also showed the highest NO free radical scavenging followed by B. campestris and B. alba. Highest reducing power (O.D. = 1.7) was observed for I. aquatica followed by P. sativum (O.D. = 1.12), B. alba (O.D. = 0.86) and L. siceraria (O.D. = 0.72) at 400 ?g/ml extract. They also displayed high total antioxidant capacity. Therefore, the top five potential leafy vegetables consist of both hydrophilic and lipophilic antioxidant(s), the order being I. aquatica &gt; B. campestris &gt; B. alba &gt; P. sativum &gt; and L. siceraria. DOI: http://dx.doi.org/10.3329/bjb.v44i1.22723 Bangladesh J. Bot. 44(1): 51-57, 2015 (March)</jats:p

Rooftop PV or Hybrid Systems and Retrofitted Low-E Coated Windows for Energywise and Self-Sustainable School Buildings in Bangladesh

The electricity crisis is a common issue in Bangladesh; however, recently the electricity scenario has been getting worse due to various reasons including power generation and distribution all over the country. Meanwhile, the large number of people requires a huge amount of energy which is not possible to be met by the national grid due to the limited power generation from different plants. Among all renewable energy sources, the solar photovoltaics (PV) system is the best choice as a generation source, either off-grid or with a grid-tied connection, to reduce the pressure on the national grid. In Bangladesh, there are more than 175,000 schools, and it is possible to generate a huge amount of renewable (solar) power to supply all the schools by using rooftop PV systems. We propose a new approach that combines solar energy harvesting and savings to make the schools self-sufficient and energywise. We performed a Hybrid Optimization Model for Multiple Energy Resources (HOMER) pro simulation and find that it was possible to generate approximately 200 megawatts (MW) of power. We conducted a feasibility study on generating power from rooftop PV systems on school buildings and reduced the power consumption using retrofitted thin-film-coated glass by around 16–20% per day depending on the school size, which can help the national power grid system by either making all the schools off-grid or grid-connected to supply power to the national grid. In addition, we perform a HelioScope simulation to investigate the maximum upscaling of PV sizing for the rooftops of school buildings in Bangladesh to realize how to make each school a mini solar power station in the future. The HelioScope simulation performance showed that it was possible to generate approximately 96,993 kWh per year from one school building