Browsing by Author "Mhilu, Cuthbert"

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    FACTORS CONTRIBUTING TO TRAFFIC FLOW CONGESTION IN HETEROGENOUS TRAFFIC CONDITIONS
    (International Journal for Traffic and Transport Engineering, 2019-05-15) Mahona, John; Mhilu, Cuthbert; Kihedu, Joseph; Bwire, Hannibal
    Most of the urban roadways do experience traffic flow congestion at various road sections called critical traffic points, which is partly contributed by the presence of various factors on the roadways. A number of studies have used travel time indices to determine congested links of the road networks. However, the travel time-delay based indices have found less application in the identification and quantification of congestion levels in the road networks. As a result, a limited number of studies have examined the factors contributing to the propagation of congestions at various road sections using the travel time-delay indices. This paper aims to identify factors contributing to propagation of traffic congestions at frequently congested traffic critical points and to estimate their influence on the entire road network using travel time-delay data. Travel time-delay data were collected by using test moving cars.The results indicate that low travel-delay transition index below 0.70 signify the jam and crowded traffic flow condition, while higher values greater than 0.70 indicate free flow phenomena. On the other hand, high congestion index values indicate jam and crowded flow conditions whereas the low values below 0.5 signify free flow conditions. Further, the results showed that low transition index and high congestion index values were associated with roadway design factors such as T-joints, cross joints, bus stops, humps and traffic lights, which are considered to be static bottlenecks which impedes the vehicle flow.
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    Non-Isothermal Degradation and Thermodynamic Properties of Pine Sawdust
    (Scientific Research Publishing, 2018-12-28) Said, Mahir; John, Geoffrey; Chaula, Zephania; Samwel, Manyele; Mhilu, Cuthbert
    The study of non-isothermal kinetics analyzed the reactivity of pine sawdust, while the thermodynamic properties analyzed energy consumed and released from the pine sawdust. The kinetic parameters were determined by analyzing mass loss of pine sawdust components by using Thermogravimeric analyzer. The cellulose has the highest conversion rate of 9.5%/min at 610 K compared to hemicellulose and lignin, which are 5%/min at 600 K and 2%/min at 800 K, respectively. The activation Energy for cellulose, hemicellulose and lignin was 457.644 kJ/mol, 259.876 kJ/mol, and 89.950 kJ/mol, respectively. The thermodynamic properties included the change of Gibbs free energy for cellulose and hemicellulose, which were −214.440 and −30.825 kJ/mol respectively, their degradation was spontaneous in forward direction, while change of Gibbs free energy for lignin was 207.507 kJ/mol, which is non-spontaneous reaction. The positive value of change of entropies for the active complex compounds formed from hemicellulose and cellulose is less stable, while the active complex compounds of lignin are characterized by a much higher degree of arrangement since its change of entropy is negative. The kinetic and thermodynamic properties show that pine sawdust is a good candidate for production of char since it is easier to remove hemicellulose through thermal process.