https://repository.seku.ac.ke/handle/123456789/2 2026-04-09T09:57:39Z 2026-04-09T09:57:39Z Gichure, Josphat N. Njage, Patrick M. Wambui, Joseph M. Dykes, Gary A. Buys, Elna M. Coorey, Ranil https://repository.seku.ac.ke/handle/123456789/8336 2026-04-08T12:16:20Z 2022-04-01T00:00:00Z

Systematic-review and meta-analysis on effect of decontamination interventions on prevalence and concentration of Campylobacter spp. during primary processing of broiler chickens Gichure, Josphat N.; Njage, Patrick M.; Wambui, Joseph M.; Dykes, Gary A.; Buys, Elna M.; Coorey, Ranil Scientific advances in pathogen decontamination offer great potential to reduce Campylobacter spp. during primary processing. The aim of this study was to collate data from eligible studies using systematic review, meta-analysis followed by meta-regression. Random effect meta-analysis revealed heterogenous (τ2 = 0.6, I2 = 98 %) pooled reduction in Campylobacter concentration of 0.6 log10 CFU/carcass and a decrease in relative risk of Campylobacter spp. prevalence in broiler carcasses by 57.2 %. Decontamination interventions during Inside-Outside-Carcass-Wash were most effective on concentration (0.8 log10 CFU/carcass) while those during evisceration were most effective on prevalence (78.0 % decrease in relative risk). Physical decontamination was more effective on Campylobacter prevalence (68.7 % decrease in relative risk) compared chemical treatment (30.3 %). Application through immersion was superior on Campylobacter concentration (0.9 log10 CFU/carcass odds reduction) to spraying (0.5 log10 CFU/carcass odds reduction). Publication bias and small study effect were observed in trials on Campylobacter prevalence but not for concentration. The meta-regression revealed four and seven potential modifier variables for concentration and prevalence respectively. This meta-analysis provides an overview of the expected magnitude in Campylobacter spp. concentration and prevalence with application of decontamination interventions on broiler carcasses along the slaughter process and forms a basis of quantitative microbial risk assessment and derivation of intervention measures. Even though modest microbial concentration reduction is reported there was a large decrease in contamination prevalence during processing interventions. https://doi.org/10.1016/j.fm.2021.103923

2022-04-01T00:00:00Z Hong, Wei Mo, Liantong Pan, Changluan Riara, Martin M. Wei, Mi Zhang, Jizhe https://repository.seku.ac.ke/handle/123456789/8335 2026-04-08T08:53:59Z 2020-01-20T00:00:00Z

Investigation of rejuvenation and modification of aged asphalt binders by using aromatic oil-SBS polymer blend Hong, Wei; Mo, Liantong; Pan, Changluan; Riara, Martin M.; Wei, Mi; Zhang, Jizhe In this paper, long-term aged base asphalt and SBS modified asphalt binders were rejuvenated and modified simultaneously using a compound rejuvenator containing 77% aromatic oil and 23% SBS polymer. Aromatic oil was used for rejuvenation purpose due to its softening effect while SBS polymer was used for modification purpose because of its potential to form a polymer network. Conventional bitumen tests, dynamic shear rheological (DSR) test and bending beam rheological (BBR) test were conducted to evaluate the rejuvenation and modification effects. Test results indicated that use of the compound rejuvenator enhanced the softening point and ductility for both aged base asphalt and SBS modified asphalt binders. The polymer modification effect of compound rejuvenator was well distinguished by the plateau region of phase angle master curves. Aromatic oil had a strong softening effect on aged asphalt binder which improved the performance at low temperatures, but weakened the performance at high temperatures. The incorporation of SBS polymer was a good supplement to balance the overall performance of rejuvenated asphalt binders. The compound rejuvenator can be greatly effective for hot recycling of reclaimed asphalt mixture by means of the simultaneous rejuvenation and modification. https://doi.org/10.1016/j.conbuildmat.2019.117154

2020-01-20T00:00:00Z Megaptche, Christelle A. Musau, Peter M. Tjahè, Agnès V. Kim, Hanki Waita, Sebastian Aduda, Bernard O. https://repository.seku.ac.ke/handle/123456789/8334 2026-04-08T08:29:24Z 2023-09-01T00:00:00Z

Demand response-fuzzy inference system controller in the multi-objective optimization design of a photovoltaic/wind turbine/battery/supercapacitor and diesel system: Case of healthcare facility Megaptche, Christelle A.; Musau, Peter M.; Tjahè, Agnès V.; Kim, Hanki; Waita, Sebastian; Aduda, Bernard O. One of the most common causes of power outages in developing countries is a global mismatch between supply and demand. The effects of this phenomenon are especially devastating in the healthcare sector. This paper describes the management of the loads' operation using Demand Response-Fuzzy Inference System Controller (DR-FIS) for the sizing optimization of photovoltaic/wind turbine/battery/supercapacitor and photovoltaic/wind turbine/battery/diesel generator systems operating autonomously in a health center in northern Cameroon using multi-objective particle swarm optimization (MOPSO) and multi-objective genetic algorithm (MOGA) methods. The assessment criteria for this optimization are Loss of Power Supply Probability (LPSP), Net Present Cost (NPC), Cost of Energy (COE), Total Greenhouse gases Emission (TGE), Wasted Energy (WE), and Renewable Generation (REG). Implementing a Demand Response-Fuzzy Inference System controller (DR-FIS) has allowed significant energy savings (15.4130% reduction in energy demand) and increased worldwide supply–demand adequacy. This study highlights the techno-economic and environmental significance of using a supercapacitor (SC) as a backup in contrast to a diesel generator (DG), as well as the validation of its compatibility with storage batteries because of the provision of a robust energy management approach. Finally, in this study, MOGA results in better results than MOPSO after evaluating the outcomes of the various multi-objective optimization methods. This strategy enabled the determination of the ideal configuration for the studied Healthcare Center's power supply. This configuration includes the Demand Response-Fuzzy Inference System. It consists of 20 solar panels (PV), 02 wind turbines (WT), 04 batteries (BT), and 07 supercapacitors (SC) for a COE of 0.1691 $/kWh, a NPC of 1.1808e + 03 $, a TGE of 439.7901 Kg, a WE of 4.0066e + 03 Kwh, 100% REG and unfortunately 0.9858 % LPSP. https://doi.org/10.1016/j.enconman.2023.117245

2023-09-01T00:00:00Z Kiruki, Harun M. van der Zanden, Emma H. Zagaria, Cecilia Verburg, Peter H. https://repository.seku.ac.ke/handle/123456789/8333 2026-04-08T08:05:50Z 2019-10-15T00:00:00Z

Sustainable woodland management and livelihood options in a charcoal producing region: An agent-based modelling approach Kiruki, Harun M.; van der Zanden, Emma H.; Zagaria, Cecilia; Verburg, Peter H. Woodland resources provide livelihoods for millions of people in Africa. Concerns about the impact of human utilization of woodlands have led to vigorous debates on woodland degradation. Ecological and socio-economic empirical data and understanding of the socio-ecological system have been synthesized in an agent-based model (ABM) to explore different woodland management options for a dynamic, semi-arid region in Kenya. In our simulations we accounted for the impacts of drought frequency, charcoal price changes, improved management practices and taxation of charcoal for a 20-year period to assess woodland changes in a spatially explicit way and evaluate the numbers of actors that can benefit from charcoal harvesting as a livelihood option. The model is based on an agent typology derived from 150 household interviews that focused on livelihood strategies and decision-making processes. Furthermore, the model integrates knowledge from vegetation plots and focus group meetings. From the model simulations we learn that favorable prices, improved management and taxation do not directly have the anticipated impact on woodland resources, as the improved conditions lead to fewer constraints on involvement in charcoal making. This reduces the positive impacts of these measures on the woodland quality but, at the same time, allows a larger number of actors to benefit from charcoal harvesting. Results show a very strong decrease in woodland area under the base scenario thereby reducing possibilities for households to supplement their incomes with charcoal making. Increased droughts and low prices for charcoal lead to early depletion of woodlands and reduction in livelihood options. Taxation stabilizes the number of charcoal producers but does not stop the depletion of woodland area. Woodland loss can only be prevented by controlling the number of charcoal makers and the amount of charcoal harvesting. https://doi.org/10.1016/j.jenvman.2019.07.016

2019-10-15T00:00:00Z