UET Peshawar Publications Site (University of Engineering and Technology, Peshawar)
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ENVIRONMENTAL GEOCHEMISTRY OF ACID MINE DRAINAGE WATER AT INDUS COAL MINE AT LAKHRA, SINDH-PAKISTAN
No full textThe annual coal production of Pakistan is about 3,637,825 tonnes which is about 6% of the country's energy resources; out of this 1,241,965 tonnes of coal was produced/mined from the Lakhra coalfield, District Dadu, Sindh which after the Thar coal field is the second largest coalfield of Pakistan. At this coal field more than 58 mining companies are engaged in exploring the hidden wealth of the country. The problem of Acid Mine Drainage, is caused by the passage or seepage of water, through mines where iron disulphides, usually pyrites, are exposed to the oxidizing action of water, air and bacteria, is the main problem faced by the mining companies. The geochemical analysis of acid mine drainage water collected from Indus coal mine No. 6 shows that beside its higher pH, Total Dissolved Solids and Sulphates, it also posses higher amount of heavy metals like Cd, Cu, Pb, Co, Ni, and Fe. This acid mine drainage water not only damages the mine structures but is also harmful to soil and ecology
COST VERSUS RELIABILITY ANALYSIS OF NEW TREE-BASED HYBRID PROTECTION ARCHITECTURE FOR OPTICAL CODE DIVISION MULTIPLE ACCESS SYSTEM
No full textConventional optical code division multiple access (OCDMA) system for passive optical network (PON) has limited applications in providing protection to network components. This increases the overall downtime of PON, and reduce its feasibility for deployment at the access domain. Therefore, it is imperative to design an economical system that should be able to provide fault detection and restoration at both feeder and the distribution level. This paper focuses on design and analysis of a novel tree-based hybrid protection architecture for OCDMA system in order to make it economical and reliable for deployment at the access domain. It is observed that the proposed protection architecture provides desirable (5 nines) connection availability along with minimum cost as compared to existing tree based protection architectures
PARAMETRIC SENSITIVITY ANALYSIS OF CONVEX STAR PORT PROPELLANT GRAIN FOR SOLID ROCKET MOTOR
No full textGrain design takes the central place in a solid rocket motor design activity. Ballistic quality of a designed grain can be evaluated by two vital indexes known as neutrality and sliver content. Sliver content results in tail-off of the thrust-time curve. These two measures of merit are an important part of acceptable grain design. This paper is restricted to the study of convex port star grain geometry and describes parametric evaluation to assess the effects of seven independent and defning geometric variables of the star and other ballistic factors including density of propellant and characteristic exhaust velocity on the burn pattern and performance profle for qualitative analysis of sliver fraction (tail-off)and neutrality. The purpose of the study is to expand the design domain by evaluating entire convex Star family under both neutral and least sliver content conditions.The computer program associated to it is essentially the ballistic design analysis of the convex star grain confguration. Results showed that neutrality and sliver fraction are dependent oncertain parameters. It has been observed that for good neutrality, higher angular fraction and star angle close to neutrality must be maintained. Sliver fraction depends upon the star geometry and can be reduced by decreasing angular fraction leading to reduced tail-off. Thus neutrality and reduced tail-off cannot be achieved simultaneously and trade-off has to be made. However, higher value of characteristic exhaust velocity (C*) will reduce tail-off
SEISMIC DESIGN CHARACTERIZATION OF RC SPECIAL MOMENT RESISTING FRAMES IN PAKISTAN-FIELD SURVEY TO LABORATORY EXPERIMENTS
No full textThis study was undertaken to study the influence of construction defciencies on hysteretic behavior of exterior beam-column connections. Building stock survey was conducted in fve major cities of Pakistan for identifcation and quantifcation of material and detailing disparities between design specifcations and construction practices. The effect of these disparities was studied using quasi-static cyclic testing on two exterior beam-column connections; EJ-1A (code-compliant) with no defciencies and EJ-2A (non-compliant) incorporating all identifed defciencies. Damage patterns and hysteretic force-deformation behavior of these models is presented and the performance of the two specimens is compared. The study found that moderate to high defciencies exist between design specifcations and construction practices for the construction of RC buildings in Pakistan. The study also concluded that significant loss of strength and ductility is observed between code-compliant and non-code-compliant exterior beam-column connections subjected to reverse cyclic loading
IRRIGATION EFFICIENCIES POTENTIAL UNDER SURFACE IRRIGATED FARMS IN PAKISTAN
No full textThe conventional surface irrigation systems, border, level basin and furrow bed, are inherently inefcient in Pakistan, while the suboptimal feld sizes (length and width) are considered as one of the main reasons of poor performance. Addressing these issues, the three surface irrigation systems were evaluated on thirteen felds under routine farmer management in Pakistan. Irrigation performance including application efciency (AE), Potential Application Efciency (PAE), Adequacy (AD) and distribution uniformity (DU), of 17 irrigation events were evaluated and further potential for improvement by optimising feld sizes were identifed using surface irrigation evaluation Model WinSRFR 4.1.3.
The study revealed poor irrigation efciencies, AElq (41% to 82%), PAEmin (43% to 95%), ADlq (1.16 to 2.29) and DUlq (80% to 99%), on farms. The average AElq on farm was in the order of; level basin (58%) < border (65%) <furrow bed (68%). Simulation modelling indicated that there is further potential to increase average PAE up-to 94%, 87% and 96% for level basin, border and furrow bed irrigated felds respectively, by optimising feld length and width. The analysis demonstrated increased understanding of the interactions of feld sizes and irrigation efciencies, which may support irrigators’ decision making for enhancing irrigation performance at no significant cost to infrastructure, machinery or labour
CHARACTERISTICS AND EFFICACY OF ULTRAFAST LASER PULSES FOR BIOMEDICAL APPLICATIONS
No full textFor the fabrication of three dimensional cell scaffolds, femtosecond laser irradiation at 800nm was used for biomedical applications. The femtosecond laser system was also used to fabricate a bricks and mortar structure in keratin flms to investigate skin structures for different cream absorption. The laser characterised here is Spectra Physics, Hurricane X. This is a complex laser system consisting of a seed laser and a regenerative amplifer. It is important to have knowledge of these characteristics to be able to predict the transport of the beam through various optical elements and also to analyse the subsequent interaction with materials. The whole optical intensity profle in two dimensional space of a laser beam i.e. across the beam radius and its detailed shape has been measured and it has been demonstrated that Ti: sapphire laser system has the ability to fabricate three dimensional structures for biomedical applications. Tissue scaffolds have been prepared with different pore sizes suitable for application in different living tissues. Polymerisation based on a direct write system to build up solid polymeric material for the fabrication of three dimensional cell scaffolds can be achieved. By tailoring the optical system and making use of a relatively weak absorption cross-section we have been able to manufacture deep structures in a single pass of the laser light
CYCLE TIME OPTIMIZATION FOR IMPERFECT MANUFACTURING SETUP FOCUSING WORK-IN-PROCESS INVENTORY
No full textImperfect production processes have been focused during recent decades for optimum lot size calculation based on average cost minimization. However, cycle time optimization has been ignored relatively when processes are imperfect and inspection as a process is considered. Furthermore, the role of work-in-process inventory with respect to cycle time has always been signifcant. Hence, this paper integrates work-in-process inventory and imperfect production setup in order to optimize cycle time based on average cost minimization. A mathematical model is developed that incorporate rework operation, rejected products produced, and inspection processes in addition to work-in-process inventory. Cycle time is optimized based on total system cost minimization. Numerical example is also used to illustrate the impact of the developed model as compared to the previously developed model. The impact of work-in-process inventory and processes imperfection on optimum cycle time is highlighted by an example
EXPERIMENTAL INVESTIGATION ON UTILIZATION OF WASTE RUBBER TIRES AS FILLER IN CONCRETE
No full textThis work has been carried out to evaluate the potential usage of waste rubber tires in concrete. Disposal of tires is a major problem and their accumulation create health and fre hazards. To incorporate waste rubber tires in construction industry is considered as a sustainable and environment friendly solution. Experiments were designed by incorporating coarse and fne rubber content as partial substitution of conventional aggregates. Seven mixtures were proportioned; one mixture with conventional aggregates was the control specimen, three mixtures were casted by replacing fne aggregate by waste rubber tires powder and remaining three were proportioned by replacing coarse aggregate by waste rubber tires chips. Fresh and hardened properties of rubberized concrete were evaluated and compared with the control specimen. The results showed that there was signifcant fall in workability of rubberized concrete along with slight deviation in the density and aesthetics as compared to control specimen. The compressive strength of rubberized concrete was found to be augmented when 10 % fne crumb rubber content was used. However with further increase in the rubber content, the compressive strength was abridged. On the contrary, there was continuous reduction in the compressive strength with the increase in the amount of coarse rubber content as compared to control specimen. It was verifed that rubberized concrete have potential to use in concrete up to some extent
FACTORS IDENTIFICATION FOR COAL BRIQUETTES MANUFACTURING USING STATISTICAL EXPERIMENTAL DESIGN APPROACH
No full textCoal briquettes are mostly manufactured through conventional methods in developing countries including Pakistan. Shortages of energy resources across the globe have pushed companies to manufacture those products with least possible costs by using signifcant factors. Indeed, the role of statistical design of experiment in general and factorial design in particular is vital in identifying these signifcant factors in comparison to the conventional techniques. This paper provides a statistical approach towards manufacturing of coal briquettes in Northern Province of Pakistan. Binder composition, pressure, particle size, and coal type are analyzed for higher calorifc value and compressive strength simultaneously. Experiments are conducted in order to obtain the response of desired variables for the given three levels of each factor. Full factorial design approach with analysis of variance (ANOVA) is deployed to get the optimum values of the response variables under the given conditions
AGE EFFECT ON THE MECHANICAL PROPERTIES OF HIP JOINT BONE: AN EXPERIMENTAL INVESTIGATION
No full textBone is one of the important body components of all vertebrates. It is a natural composite, composed of bonesalt plates as matrix binder and soft collagen as reinforcing fbers. As bone supports all the organs of a body so its mechanical behavior is of prime importance. The mechanical properties of bone varies with age. In this paper, the effect of age on various mechanical properties of hip joint bone was investigated experimentally. For this purpose hip joint bone specimens of male bovine of different age groups were tested for fracture toughness, young modulus and tensile strength in the longitudinal and transverse directions of the collagen’s fbers. Compact tension specimen was used for the fracture toughness, while for young modulus and tensile strength, rectangular flat specimens were used. The test procedures were similar to ASTM (American standard for testing and measurements) techniques. The test result revealed reduction in mechanical properties of hip joint bone with the age