UET Peshawar Publications Site (University of Engineering and Technology, Peshawar)
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MODEL FOR UNSATURATED FLOW THROUGH SOIL: SENSITIVITY ANALYSIS AND APPLICATION
No full textAn applied numerical unsaturated flow model was developed in the previous paper to describe the movement of water in a homogeneous soil The model was based on the Richard’s equation for partially saturated flow in porous media along with real boundary conditions, which was solved using finite difference scheme. This paper is mainly focused on the model flow chart and its application to unsaturated moisture flow problems. Various options are considered using real boundary conditions. A sensitivity analysis of different parameters was undertaken in order to determine the most sensitive parameters of the model. It was found that the saturated hydraulic conductivityis the fundamental parameter governing the flow phenomena in unsaturated soil. From these analyses it is concluded that the model provides a useful tool in determining the moisture distribution and movement within unsaturated soilzone and it can be used independently or as a part of larger hydrological model
SHEAR AND FLEXURAL BEHAVIOUR OF R.C. SECTIONS WITH INDIGENOUS AGGREGATE
No full textIn all, fourteen RC beams were tested to study the shear as well as flexural behaviour of concrete with brick pieces as coarse aggregate. The experimental work is divided into four groups; two for shear and two for flexure. Both, for shear and flexure, one group each respectively was cast with stone aggregate for the sake of comparison. Full non-linear analysis of all the beams was performed with the help of a three-noded, isoparametric, layered, one-dimensional element with smeared layer of steel, using constant stiffness matrix. All the beams tested during this study were simply supported and only a single point load was applied at the centre of the effective span. The behaviour was studied in terms of load-displacement history, distribution and redistribution of compressive stresses in concrete at the point under the load at different stages of loading, crack pattern, mode of failure and ultimate load
PERFORMANCE ANALYSIS OF EXISTING LOCAL LOOP IN PAKISTAN FOR ISDN ENVIRONMENT
No full textTelecommunication facilities form a vital part of the economic infrastructure of a country. These also influence all other sectors of the national economy. Subscribers are demanding new applications, new technologies and more services. Thus Integrated Services Digital Network ( ISDN ) is growing rapidly. A significant portion of the Pakistan Telecommunication Corporation ( PTC) asset comprises of copper cables in local loop. Its evaluation is very important because of its inability of high bit rate transmission and operation and maintenance difficulties due to electromagnetic interference and moisture etc. Copper loop detailed study and evaluation was felt more necessary and timely. Work remained confined to existing copper loop as data traffic in Pakistan has not arrived at such a level to justify optical fiber in local loop at this early stage. Case of Islamabad is studied, however the theory and test procedures are applicable all over the PTC network. The paper concludes with the results and recommendations for future work.
 
IMPACT OF HYDROGEN ON SAFETY OF NUCLEAR REACTORS
No full textVarious sources of hydrogen gas generated in a water cooled reactor (WCR) during normal operation and in case of an accident are identified. Their impacts on the safety of WCR and preventive actions to preclude accident or minimize the hazard there of are described
EXPERIMENTAL STUDY OF STRUCTURAL PROPERTIES OF LOCAL TIMBER
No full textExperimental study has been conducted to determine the fundamental structural properties such as compressive strength, tensile strength and material constants such as modulus of elasticity and Poisson's ratio of different kinds of local timber. Eight varieties have been selected i.e. Talhi, Neem, Babool, Chilghoza, Dayal, Paltar, Cheel and Mango. The tensile strength has been studied by testing timber bars by adopting the procedure which is common for steel; while for compressive strength cubes analogous to concrete have been tested with wood fibres in erect position. Cylindrical specimens have been used for modulus of elasticity and cubes for Poisson’ s ratio. It is encouraging to note that the material properties of local varieties of timber are as good as those reported in literature for alien types
A STUDY OF THE EFFECT OF AQUATIC IMPURITIES ON THE STRENGTH OF CONCRETE
No full textAn experimental study, the details of which are presented in this paper pertains to the effect of water impurities particularly dissolved salts and turbidity in the water from various sources such as river water, ground water\ public health department water, sea water and LBOD water which is commonly used for mixing and curing of cement concrete. Pure distilled water has also been used for the sake of comparison. Chemical analysis of the water has been done to know the nature and quantity of dissolved salts in the water obtained from various sources. This study includes the determination of compressive strength, tensile strength, modulus of elasticity and poisson’s ratio
WAVE PROPAGATION IN AN ANISOTROPIC (INCOMPRESSIBLE, TRANSVERSELY ISOTROPIC) ELASTIC MEDIUM ROTATING ABOUT THE AXIS OF SYMMETRY
No full textThis paper discusses the velocity of homogeneous plane waves in an incompressible, transversely isotropic elastic medium rotating about its axis of symmetry. The rotational effect contributes nothing when the wave is polarized about the axis of rotation. It is shown that if the polarization is in the plane of isotropy then two types of waves can propagate along the axis of symmetry. For any other orientation of the polarization vector three types of waves can propagate in it.
 
EFFECTS OF TEMPERATURE GRADIENTS ON EVAPORATION AND SALT MOVEMENT THROUGH SOIL IN THE PRESENCE OF A SHALLOW WATER TABLE
No full textA series of experiments was performed in an insulation chamber to elucidate the effect of temperature gradients on evaporation. These experiments were conducted on Rivington sandy loam soil, packed into vertical columns, in which there were fluxes both into ( from a water table at 55 cm depth ) and out of the soil (evaporation to the atmosphere). The soil-surface temperature ranged from 30-50°C and the evaporation from open water surface ranged between 7 and 26 mm /d.Temperature gradients had a significant effect on the evaporation and on the salt transfer through the soil. The greater the temperature gradients, the faster the evaporation rate fell to a steady value ( generally less than 1 mm/d). The shallow water table contributed significantly to evaporation and the soil salinization. The cumulative groundwater contribution to the soil surface evaporation was 80%, 50%, 90% and 55% under continuous radiation, continuous radiation + wind, intermittent radiation + wind and continuous wind, intermittent radiation treated columns, respectively. The ECe at the soil surface (0-2 cm depth) increased from 0.094 dS/m to 2.0, 1.5, 3.6 and 1.09 dS/m for continuous radiation, continuous radiation + wind, intermittent radiation + wind and continuous wind, intermittent radiation treated columns, respectively.
 
MODELLING OF SHEAR SOCKETED PIERS IN ROCKS PART - 3: NUMERICAL ANALYSIS
No full textIt is widely accepted that the pier-rock interface governs the strength and load-deformation behaviour of shear socketed piers. A combined laboratory and analytical study was initiated to address these key issues. This paper; which is the third of a three part series, focuses on the important features of a newly developed plasticitybased interface model. The model describes the mechanical behaviour or rock-concrete interface. Various features of the model such as the failure criterion, plastic potential, bond degradation and dilatancy, are discussed. The isoparametric formulation of the zero thickness interface element and the implementation procedure of the constitutive laws into a standard non-linear numerical code is briefly described. A failure criterion for rock joints is developed and is shown to fit well the direct shear test data obtained for sawtooth interfaces. The predictive performance of the interface (constitutive ) model is assessed by comparing numerical results and experimental data presented in two companion papers ( Parts 1 & 2 )
HARMONICS IN DISTRIBUTION SYSTEM PROBLEMS AND REMEDIES
No full textThis paper presents an analysis of harmonic sources in distribution system, the frequency dependent models of the network elements and effects of harmonics on these elements. The parallel resonance condition appears in the system (by the paralleled combination of P.F. correction capacitor and system impedance). Significant voltage distortion will result due to large impedance. It will effect the system badly. Filtering techniques have been used to rectify this resonance condition.