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.

Synthesis and Characterization of Polymeric Membranes for Dialysis Application

Membrane is a thin, delicate, flat sheet which acts as a barrier for selective transport of species under the impact of some driving force. Membrane technology has gained important place in industrial and medicinal field because of its easy utility, efficient performance and low cast. Hemodialysis is an extensively used medical therapy for renal failure and dialysis membranes are essential components of a hemodialysis. The essential properties of a dialysis membrane are high mass transfer of toxic solutes (urea and uric acid) to reduce the dialysis time, maximum protein rejection ability and moderate water flux. Protein adsorption or deposition on the surface or in its pores results in reduction in flux, change of selectivity of the membrane and the low toxin elimination. Polymeric membrane fabricated from cellulose, regenerated cellulose and synthetic polymers are well known for dialysis. Asymmetric Cellulose Acetate (CA) membranes were prepared through phase inversion method and they were modified by blending various organic and inorganic additives. The effects of these additives on membrane’s morphology were investigated using Atomic Force Microscopy, Scanning Electron Microscopy, Fourier Transform Infra-Red Spectroscopy and Contact Angle. Fabricated membrane’s performance was studied in terms of pure water flux, porosity, water uptake, BSA rejection and urea clearance tests. Biocompatibility and blood mimic tests were conducted to find the interaction of synthesized membrane towards cell culture and blood comparable fluids. In first part, CA was blended with poly-ethylene glycol (PEG). The membranes were modified by blending CA/PEG casting solution with glycol. The modified membrane showed good selectivity for urea but was not suitable for dialysis operation. Hence, the composition was reformed using Hydroxyapatite particles (inorganic additive). The results showed enhanced BSA rejection and urea clearance but the obtained percentages were low to be utilized in dialysis. The biocompatibility outcomes of CA/PEG/HA membrane make it appropriate for other biomedical applications. In the second part, CA was blended with organic additives including sericine, Poly vinylpyrolidone (PVP) and polyethylene imine (PEI) to improve BSA rejection and Urea clearance of polymeric membrane. These membranes possess moderate pure water flux and hydrophilicity. Performance evaluation investigations confirmed that all these membranes had good pure water flux and BSA rejection above 90%. Membranes fabricated using blend of CA and PEI have highest urea clearance of 67.2%. So, this membrane was selected for further adjustment. During the last part, effect of solvent on CA/PEI dialysis membrane was investigated. Various solvents including acetic acid, formic acid, N, N-Dimethylacetamide (DMAC) and 1-Methyl-2-pyrolidone (NMP) were tested. The performance efficiency of synthesized membranes verified to, when CA was blended with formic acid (F.A) have desired dialysis characteristics. It possesses moderate hydrophilicity, desired pure water flux value, optimum water uptake, above 98% BSA rejection and urea clearance percentage of 69%. The biocompatibility tests were conducted for CA/PEI/FA membrane using MTT (3-(4,5- dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide )assay. It was found that the materials selected for this membrane fabrication were most suitable for dialysis application. Highest cell viability and cellular attachment found in biocompatibility analysis was higher in comparison with commercial dialysis tubing and non-treated control standard. CA/PEI/F.A membrane was further inspected via blood mimic solution to find the performance of membrane commensurate with blood type feed. The up short of the present work is that CA/PEI/F.A membrane is the best possible solution for dialysis. Providing new insight in the dialysis domain; this membrane is not only cost effective but also has high BSA rejection and Urea clearance. Accordingly, biocompatibility and blood mimic results prove it to be the finest device/implant for hemodialyser unit.