UET Peshawar Publications Site (University of Engineering and Technology, Peshawar)
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SYNTHESIS AND CHARACTERIZATION OF ION EXCHANGERS THROUGH CONTROLLED GRAFTING OF 4-VINYLPYRIDINE ONTO STYRENE-DIVINYLBENZENE
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Macroreticular ion-exchange resins with 4-vinylpyrirline grafted onto styrene-divinylbenzene were synthesized by the suspension polymerization technique. Study of effects of degree of grafting on the texture of S-DVB copolymer and on the ion exchange kinetics is presented. The degree of grafting was controlled by the time of graft polymerization reaction. It was found that 2 to 3 hours of reaction time was found to be the optimum for the synthesis of the ion-exchangers with good ion exchange kinetics and reasonable capacity. Infrared spectroscopic monitoring of residual double bonds, ion exchange capacity, break through capacity for ferric chloride complex, pore volume by mercury porosimetery and self diffusion coefficient for ferric chloride complex are reported.
 
A STATISTICAL APPROACH TO STUDY THE MAXIMUM DRILLING DEPTH FOR GROUNDWATER PRODUCTION WELLS. A CASE STUDY FROM KANDY, SRI LANKA
No full textHydrogeological investigations were carried out to provide high quality groundwater for the people living in rural areas. Under this programme 14 production wells were constructed by drilling to use available groundwater at the pre-selected locations where the elevations are comparatively lower than the other areas in the studied area.
The borehole reports in which the detailed informations of drilled locations have been recorded, were used to analyse the subsurface fracture systems and the variations of flushing yields with depth and relevant mean sea levels. The total flushing yields and total number of fractures in each 5 meter depth of every well were used as frequency tables.
The results indicate that drilling more than 60 meters below the surface level is a loss and no sufficient groundwater will be available except in very few locations. A maximum drilling depth according to mean sea level cannot be recommended because horizontal fractures may not occur in a complex geological area. These results are valid only for this region but the introduced method can be used forany other to find a maximum drilling depth
EFFECT OF HEAT AND MECHANICAL SURFACE TREATMENTS ON THE FATIGUE PROPERTIES OF SAE 8620 STEEL
No full textIn this study, the fatigue properties of SAE 8620 case hardened steel was investigated. Carburizing, shot peening and their combinations were applied to SAE 8620 steel fatigue specimens. Different fabrication parameters of carburizing were applied. Shot peening was also applied to carburized and noncarburized specimens. Hardness and residual stress distribution of mechanical and heat-treated fatigue specimens were determined. Rotating bending fatigue tests were performed using treated test specimens. Plotted S-N curves, for treated at different conditions and different ways, were compared to curves for drawn specimens. The maximum increase in fatigue limit is determined for double quenched and shot peened specimens as 72%
DISTRIBUTION OF LINEAR COMBINATION OF NON-NORMAL RANDOM VARIABLES
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In this article an example based on a class of probability density functions ( pdCs) is presented which would enable us to deal with two different situations related to (non) normal random variables. A straightforward generalization is also given.
 
CHARACTERISTIC ROOTS OF THREE PARTIAL DIFFERENTIAL EQUATIONS FOR SEDIMENT TRANSPORT
No full textThe unsteady flow of sediment-laden water may be formulated in terms of three one dimensional partial differential equations. Two of these equations are the well known Saint Venant continuity and dynamic equations of motion and the third is a mass balance equation for sediment flow. A complete analytical solution of these equations cannot be found because of their complexity. To find their numerical solution a prior knowledge of characteristic roots of these equations is very important. The characteristic roots of these equations are found in this paper. The initial and boundary conditions for the numerical solution of these equations are also studied
EFFECT OF TAP-CHANGER ON WAPDA 500/220 KV SYSTEM
No full textUsing a Standard Test Circuit for 500/220 KV WAPDA transmission system, admittance bus matrix is found. The admittauce bus matrix is then modified to include the effect of tap changer. A computer program using FORTRAN 77 to run on main frame Micro vox 3100 is written to calculate the effect of different taps on bus bar voltages, VAR flow in lines and VAR generation at generation buses. This program is tested on IEEE 5,6 and 16 bus test systems and the results are in vety close agreement.
There are seven transformers in the WAPDA system with tap-changing gears. The effect of each tap for each transformer is studied and the working tap range for each transformer is found. The effect of taps on the lines near the transformer bus is found to be enormous, while effect on other lines, far from transformer bus, is negligible.
Newton-Raphson method in polar co-ordinates is used for voltages and line flow calculations. The results are presented in tabular form so that the working tap range of each transformer, for which voltages and VAR flows are within specified limits, can be read easily.
The voltage variation at a node is an indication of the unbalance between the reactive power generated and consumed by that node. If the reactive power generated is greater than that consumed, the voltage goes up and viceversa. Whenever the voltage level of a particular bus undergoes variation this is due to the unbalance between the two VARs at that bus
EFFECT OF SOME POSTHARVEST TREATMENTS ON THE PHYSICO-CHEMICAL AND ORGANOLEPTIC CHARACTERISTICS OF MANGOES
No full textEffect of Wax-coatings and growth regulators on the postharvest life of Anwar Ratol, Dusehri and Samar Bahisht mangoes was studied. Waxing (2— 6% total solids) reduced weight loss and delayed the ripening process as shown by retention of ascorbic acid, slower increase in total soluble solids, sugars and slower decrease in acidity. Maleic hydrazide (500-2000 ppm) had no effect on the ripening process whereas 2, 4-dichlorophenoxyacetic acid (500 ppm) adversely affected the ripening process and the quality of fruit
PREPARATION OF 6ROMO - 1.3 BIS (METHYLTHIO) PROPANE TRICARBONYL- MANGANESE AND ITS IR NMR SPECTRAL STUDIES
No full textThe compound Brome—1, 3-Bis (Methylthio) Propane-Tricarbonyl-Manganese was prepared by the interaction of 1,3-bis (methylthio) propane and brome-pentacarbonylmanganese (1). Its structure was established spectroscopically
TIME - DOMAIN ANALYSIS OF HARMONICS GENERATED BY 3 –PHASE CONVERTERS IN SUPPLY NETWORKS
No full textIn this paper the effects of harmonic currents and voltages on the power system are discussed and their remedial measures are then suitably assessed. This paper also examines the validity of the conventional methods used for the evaluation of the converter harmonics in power systems. Conventional approach is based on several simplifying assumptions and are discussed in detail. Finally, a time-domain approach based on state-equations has been investigated and suggested that this approach is more suitable in tackling discrete problems efficiently
INCREASING THE CAPABILITY OF SALIENT POLE SYNCHRONOUS CONDENSERS IN THE UNDER EXCITED REGION
No full textThe paper examines theoretical basis of the operation of a synchronous condensers with negative excitation. The object is to increase the capacity of the machine to absorb reactive KVA from the system. Operation in this Region and the stability of the condenser are dealt with