UET Peshawar Publications Site (University of Engineering and Technology, Peshawar)
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NUMERICAL MODELLING OF LEACHATE PRODUCTION FROM LANDFILL SITES: THEORY AND DEVELOPMENT
No full textAn applied numerical model NUMMOL ( NUMerical Modelling of Leachate ) has been developed to simulate the water movement into, through and out of landfills. The model accepts precipitation, potential evapotranspiration and landfill design site data, as inputs from the user. It uses solution techniques that account for the runoff, infiltration, surface storage, percolation, lateral subsurface drainage, leachate recirculation, unsaturated flow, saturated flow, flow to drainage systems and seepage losses through a clay liner. These processes in a landfill are linked together in a sequential order starting at the surface, proceeding downwards through the landfill profile to the bottom. The solution procedure is applied repetitively for each day as it simulates the water routing throughout the simulation period. The primary purpose of the model is to estimate the leachate quantity and to assist in the comparison of landfill design alternatives as judged by their water balances
AN EVOLUTIONARY APPROACH FOR CMS DESIGN
No full textCellular Manufacturing Systems (CMS) have been widely considered as the most efficient manufacturing systemsin the case of medium variety and medium volume of production. The main advantage of CMS lies in the effectivegrouping of parts into families and machines in to corresponding groups as it results in minimizing the number ofintercellular moves. Over the years, a number of efficient approaches have been developed by researchers to handlethe Cell Formation Problem (CFP). Among these, a large number of approaches consist of Artificial Intelligence(AI) based techniques. The main advantage of such approaches is their ability to handle the CFP effectively both interms of accuracy and computational effort. Following the same trend an evolutionary algorithm has been developedduring this research by combining Standard Genetic Algorithm with a very effective Local Search Heuristic (LSH).The results show that it is efficient both in terms accuracy and speed of convergence (CPU time)
DESIGN OF A LOW NOISE, LOW POWER AND SPURIOUS FREE PHASE FREQUENCY DETECTOR AND CHARGE PUMP FOR PHASE-LOCKED LOOPS
No full textThis paper presents a very simple approach to design effective PFD (Phase Frequency Detector) and charge pump (CP)circuitsfor high frequency Phase-Locked Loop (PLL) applications. ThePFD design uses only six transistors for the detection process, which reduces the chip area and power consumption of the PLL block. It also minimizes the dead zone and eliminates the reset path to reduce the delay. The output is passed through a buffer to suppress the distortion and to reduce the overall output noise. Phase noise has been reduced to -156 (dBc/Hz) at 1 MHz offset frequency. A simple current mirror based charge pump circuit is presented next. The charge pump design incorporates the use of transmission gates and transistors as capacitors to reduce switching error and clock feed through. The proposed design has a symmetric structure in terms of W/L ratios,transistor positioning and number of transistors in both up and down network, which produces a stable charging operation and reduces the spurious jumps in the output voltage. The overall output noise including thermal and flicker noise of the complete design at high frequencies is as low as -213 db at 4GHz. The proposed design provides ahigh output voltage swing of 1.4V while operating at 1.5V supply voltage. The design has been implemented in 1P-9M UMC 90nm CMOS technology. Simulations show the effectiveness of the design in terms of lower power consumption, lower noise and reduced distortion
RULE-BASED IDENTIFICATION OF BEARING FAULTS USING CENTRAL TENDENCY OF TIME DOMAIN FEATURES
No full textVibration-based time domain features (TDFs) are commonly used to recognize patterns of machinery faults. This study exploits central tendency (CT) of TDFs to develop a Rule-based Diagnostic Scheme (RDS), which identifies localized faults in ball bearing. The RDS offers an accurate and efcient diagnostic procedure, and purges the requirement of expensive training of conventional classifer. A test rig is used to acquire vibration data from bearings having localized faults, and various TDFs are extracted. It is worth mentioning that fluctuations in random vibration signals may alter the feature values. Therefore, each of the TDFs is processed statistically to approximate its reliable central values (CVs) against the respective faults. In this way, every feature provides a set of CVs, which are equal in number to that of faults. Separating distances among normalized CVs (NCVs) in a set provide the criteria to select or discard that particular feature before further processing. The selected sets of NCVs are fnally used as references to generate rule-set for testing the unknown vibration samples. The results are evident that the proposed RDS may be an effective alternative to the existing classifer-based fault diagnosis, even if the vibration signals are contaminated with considerable background noise
COMBUSTION OF MULTIPLE INTERACTING LIQUID JETS
No full textThe major source of pollution emission in the big cities is due to combustion of liquid fuel in various devices such as industrial gas turbines, diesel engines and conventional spark ignition engines. In many of large combustors, multiple burners are employed to supply the required amount of fuel. Depending upon the design of multiple spray burners, the efficiency of combustion process is affected. Photochemical Ozone and airborne toxic are identified as a source of series human health and environmental problems. Combustion of liquid fuel is extremely complex phenomenon. The overall effectiveness of spray combustion depends on the physico-chemical processes occurring in the near nozzle region including, vaporization, turbulent mixing, and chemical kinetic processes. The present experimental study is conducted to investigate the effects of fuel injection orientation on combustion process. The study is conducted to investigate the effects of fuel injection orientation on combustion process. The study is conducted by employing two side jets impinging on a vertical central jet at (i ) 30 deg. (ii ) 45 deg and (i i i ) 60 deg inclination to the horizontal. Jet interesting namely a/d=30.9 where “ a ” is distance between the jets and “ d” is the atomizer exit diameter, that is kept constant through out the study. The injection orientation primarily affects the turbulent mixing process. Among the three injection orientation, The 45 deg injection angle has the strongest mixing effects on combustion which leads to lower carbon monoxide formation, higher production of carbon dioxide and nitric oxides
EFFECT OF MAXIMUM SIZE OF AGGREGATE AND ITS GRADATION ON THE SHEAR CAPACITY OF R.C BEAMS WITHOUT WEB REINFORCEMENT
No full textA total number of eighteen reinforced concrete beams without web reinforcement were tested primarily to know the variation of shear capacity of reinforced concrete beams by changing maximum size and gradation of coarse aggregates.It was observed that shear strength varies much with change in gradation than change in size of aggregate i.e. surface area of aggregates. In fact shear strength increases more with improvement in gradation i.e. gradation which would produce a dense concrete than increase in size of coarse aggregates
STUDY OF SLIVER UNIFORMITY AND FIBRE GROWTH AS AFFECTED BY ALTERING THE CARD GAUGES
No full textDifferent Card gauges were studied on high production card machine, and their effect was observed sliver and yarn quality. It was noted that results produced highly significant effect
EXPERIMENTAL ANALYSIS OF BRIDGE PIER SCOUR PATTERN
No full textoai:ojs2.journals.uetjournals.com:article/2Being an important component of a transportation system, bridge piers needs to be properly designed for scouring around its piers. For proper design of bridge piers, appropriate investigation of scouring patterns is extremely important for various sizes and shapes of such piers. Without having research based knowledge of such patterns, it becomes extremely difficult to predict/minimize the scouring effects ultimately leading to severe pier damages. In this research study, experimental investigation is carried out to find the scouring patterns in terms of scour depth and its extent in lateral direction for circular and square pier models. For this purpose a number of experiments were conducted in the physical modeling laboratory of River Engineering and drainage control, USM, Malaysia. The study shows that the pier scour depth and affected area around pier increase with the increase in pier size. The study further demonstrates that the square pier models results in greater scour depth and area as compared to circular pier models. Magnitudes of scour depths and area with reference to variation in shapes and sizes of piers are also presented in this paper, along with contour maps of scour depths, both on upstream and downstream sides
A DISTRIBUTED GENETIC ALGORITM AND A-PRIORI ALGORITHM FOR THE HUB AND FACILITY LOCATION PROBLEMS
No full textA-priori is an influential data mining algorithm employed in market basket analysis to understand the purchasebehavior of buyers. It has many other applications. In this study, we combine a-priori with a genetic algorithm (GA)to solve two classical NP-hard location problems namely the Un-capacitated Single Allocation Problem (USAHLP)and Un-capacitated Facility Location Problem (UFLP). A distributed model of the proposed algorithm has beenimplemented. The performance of the algorithm has been evaluated with standard benchmark problems for USAHLPand UFLP. Results have been found encouraging
Analyzing the Effect of Squeeze Casting Process Parameters on Mechanical Properties of Overcast Al-Alloy Joint using RSM
No full textThis study contains, the overcast 2024-2024 wrought aluminium alloy joints produced by casting liquid 2024 wrought aluminium alloy onto the solid 2024 wrought aluminium alloy inserts using squeeze casting process. The quality of overcast joints fabricated via squeeze casting depend on mechanical properties such as ultimate tensile strength and yield strength. Mechanical properties depends upon the input casting parameters named as squeeze pressure, pressure duration and melt temperature. Response surface methodology (RSM) was employed to analyze the effect of above mentioned input parameters on UTS and YS. Empirical models for UTS and YS were developed which help the practitioners to achieve desired UTS and YS by using optimum vales of input parameters. ANOVA results shows that melt temperature has most significant effect on UTS and YS followed by squeeze pressure and pressure duration. Current study will provide efficacious approach to develop advance functional and structural materials