Sustainable Research and Innovation Proceedings

Germination Response of Striga hermonthica Ecotypes from Western Kenya upon Exposure to Maize Root Exudates

2025-04-07T09:52:42Z

Germination Response of Striga hermonthica Ecotypes from Western Kenya upon Exposure to Maize Root Exudates Mulaa, Elvin Elizabeth Striga hermonthica, commonly known as witchweed or ‘cereal killer', is a root hemiparasite of cereals, germinating only in response to host-induced molecules, strigolactones (SL). It continues to pose a serious threat to maize production in western Kenya, resulting in up to 100% crop failure. Percent germination of Striga is an important indicator of the virulence level of the parasite as it translates to high attachment to the host roots and varies based on the SL profile. However, specificity of Striga ecotypes when exposed to germination stimulants from host root exudates of differential testers of maize is unknown, hindering deployment of effective management strategies. The study sought to establish variations in virulence among Striga ecotypes based on crude root exudate-induced germination. We hypothesized no variation in germination responses among the Striga ecotypes. In vitro germination assays were used to determine differences in virulence among 5 Striga ecotypes collected from maize, sorghum, and finger millet fields in western Kenya using crude root exudates from two maize genotypes, WH403 (susceptible) and KSTP94 (resistant). Striga germination data was recorded by counting Striga seeds with a protruding radicle. All Striga ecotypes germinated in response to root exudates of KSTP94 and WH403. However, variations were observed among the ecotypes, (P < 0.05) with Alomodoi sorghum ecotype recording the highest germination in exudates of WH403 (81.9%). Bunyala sorghum ecotype recorded the lowest germination as induced by the genotypes WH403 (35%), and KSTP94 (37%). The two maize genotypes varied in their ability to induce Striga ecotype germination (P < 0.05). Results suggest that the virulence of Striga ecotypes could be genotype specific. These novel outcomes necessitate using Striga germination response rate as a virulence factor in Striga virulence assays and the development of region-specific resistant genotypes. We recommend further analysis of the crude root exudates to ascertain the active compounds as well as genomic analysis of the Striga ecotypes. Scientific, Technological and Industrialization Conference

Dual-band fractal antenna with concentric ring-shaped defected ground plane structure

2025-02-08T10:17:32Z

Dual-band fractal antenna with concentric ring-shaped defected ground plane structure Miring’u, Edwin Kimani; Langat, Kibet; Konditi, D. B. O. This paper proposes the design of improved dual-band micro-strip antennas through the use of concentric rectangular fractals in the patch, and a ground plane with a concentric ring-shaped defected ground plane structure, located at the bottom of the same antenna. This design technique constitutes the fractal antenna with concentric ring-shaped defected ground plane structure. The design will be undertaken in two successive iterations. The antennas proposed in this paper have dual-band resonances at 1.7375 GHz and 2.0375 GHz for the 1st iteration, and 1.7625 GHz and 2.075 GHz for the 2nd iteration, with -10 dB impedance bandwidths of 72.5 MHz and 65.5 MHz for the 1st iteration, and 58.8 MHz and 66.8 MHz for the 2nd iteration. The designed antennas can be used for telecommunication and satellite applications. Keywords— Defected, fractal, micro-strip, multi-band. Proceedings of the Sustainable Research and Innovation Conference, JKUAT Main Campus, Kenya 2 - 4 May, 2018

Distribution Generation and Capacitor Placement in Distribution Systems

2025-01-17T12:42:30Z

Distribution Generation and Capacitor Placement in Distribution Systems Chege, Simon N.; Murage, David K.; Kihato, Peter K. Distribution systems form a critical part of the power system by linking the consumer to the transmission system. Distribution systems are extensive, complex and require adequate planning to ensure reliability and reduce installation and operation cost generated by both voltage instability and network power loss. High power losses and voltage instability are the main challenges facing power distribution companies. These challenges are mitigated by capacitor and distributed generation placement in the distribution network. The effectiveness of these measures is greatly dependent on optimally placing and sizing these components within the distribution network and also, how their operation is coordinated. Due to the complexity of the distribution networks, planning of placement becomes a complex task. It therefore requires network planners to develop methods that optimally place capacitors and distributed generations (DGs) in distribution networks. In this paper a novel way of DG and capacitor placement is proposed. The method uses Voltage Stability Index to find the optimal location of DGs and Capacitors. Evolutionary programming algorithm is employed to determine the sizes of the DGs and Capacitors to be placed at the identified locations. The aim is to enhance the voltage stability of the radial distribution network. This method is tested on the IEEE-33 bus radial distribution network. Simulation is carried out in MATLAB. Keywords— Capacitor Placement, Distributed Generation, Evolutionary Programming, Voltage Stability Proceedings of the Sustainable Research and Innovation Conference, JKUAT Main Campus, Kenya 2 - 4 May, 2018

Continuous decontamination of metal-polluted mine water using engineered hybrid adsorbent

2025-01-17T12:24:09Z

Continuous decontamination of metal-polluted mine water using engineered hybrid adsorbent Muliwa, A. M.; Onyango, M.S.; Maity, A.; Ochieng, A. Mining industries contribute enormously to water pollution through discharge of effluents contaminated with metals. Metals-polluted water is a threat to aquatic and human lives as well as the general ecosystem. Numerous conventional treatment methods are available for the removal of metals from mine water, but majority of them are costly, inefficient for trace metal concentration, and generate voluminous secondary sludge. Therefore, there is need for alternative low-cost novel technologies capable of reducing metal concentration in water to acceptable levels. Adsorption technology is increasingly receiving preference because it is simple in design, requires low initial cost, easy to operate, can remove contaminants in trace levels and the possibility to develop and employ wide variety of adsorbents. This study, therefore, explored the removal of manganese [Mn (II)] from aqueous solution using a bentonite/metal oxide hybrid (B/MeOx/H) hydrogels adsorbent packed in a fixed-bed reactor. The adsorption performance was examined by breakthrough behaviors under various experimental conditions such as bed height and influent flow rate. It was found that increase in bed height resulted to increase in both breakthrough and saturation times, while it was opposite with influent flow rate. The breakthrough curves were characterized by slightly flatter breakthrough curves for large bed depth and low flow rate. The overall adsorption performance of the fixed-bed column highly depended on the operating parameters. The experimental breakthrough data was sufficiently described by Yoon-Nelson model. Bed depth service time (BDST) predicted well the breakthrough times for different flow rates. The findings demonstrate that B/MeOx/H hydrogel adsorbent could effectively polish mine water laded with trace concentration of Mn (II). Keywords—Adsorption, Breakthrough, Hybrid, Mine water Proceedings of the Sustainable Research and Innovation Conference, JKUAT Main Campus, Kenya 2 - 4 May, 2018