Impact of a Non-Dedicated U-Turn on Traffic

Non-dedicated U turn has a direct effect on road safety, capacity and congestion during the traffic flow. U turn can have significant supremacy on traffic flow and headway. Therefore to study the impact of non-dedicated u turns on traffic is the ultimate requirement of the current time. This is a microscopic traffic study in which the data from a U turn (33°59’48.2"N 71°27’30.2"E) on road leading to Hayatabad and Karkhano in Peshawar is evaluated in terms of headway, speed and flow rate of traffic. Factual data is presented which shows that the average time headway surges when the traffic is interfered by the U turning vehicles. The probability density functions and cumulative density functions fit to the datasets of headway are then evaluated by the techniques of anova analysis to determine which distribution is the most suitable one for the data. Distribution data specific with the interfering U turn was taken in a separate set and evaluated. The result obtained show that the Burr Distribution and Generalized Extreme Value Distribution are the optimum to illustrate the headway data of traffic being interfered by U turning vehicles. This ligitimize the utilization of various time headway distributions of vehicles being interfered by U turning for traffic modeling.

Design, Development and Performance Evaluation of Biomass Gasifier for Power Generation

The current study reveals various features that can affect the gasification process to improve syngas quality and yield. A comprehensive study was carried out using a 24 kW downdraft gasifier to evaluate the effect of uniformly distributed air in the oxidation zone, additional throat on the gasifier internal thermal profile distribution and the overall gasification process. The effect of biomass moisture, equivalence ratio, gasifying agent type and pre-treatment of the gasifying agent on producer gas yield and composition were also evaluated. The gasifier unit was equipped with cyclone separator, wet scrubber, water gas separator, biomass filter, auxiliary filter, cooling tower and vapour compression refrigeration system. The maximum flow rate of producer gas was found to be 90-104 m3h-1 under the biomass feeding range of 30-40 kgh-1. When corn cobs and waste wood (carpenter waste) with moisture content from 5-30% were used as feed stock, with 70ºC air as the oxidizing agent, the energy value of the producer gas obtained was 6.31 and 6.66 MJm-3, respectively. The heating value was improved to 6.72 and 8.43 MJm-3 when using 150ºC air-steam mixture as the gasifying agent, with the optimum equivalence ratio of 0.30. The Methane, Hydrogen and Carbon monoxide concentration (on volume basis) were found to be 6.20, 19.32 and 21.00%. The average amount of syngas produced from one kg of corn cobs and waste wood were 2.94 and 2.62 m3, while the average amount of tar produced was 2.2 and 1.8 gNm-3 respectively. The efficiency of cleaning and cooling system were found to be 86.81 and 92.06%. The experimental research concluded that uniformly distributed air in the combustion zone as an interconnected parameter with biomass moisture level, type of gasifying medium and pre-treatment/pre-heating of gasifying agent played a vital role in affecting the syn gas production and composition. Keywords: Gasification, Gasifier, Equivalence ratio, Gasifying agent, Pre-treatment, Syngas.