Mehran University Research Journal of Engineering and Technology

4

Authors: Pathan A.G., Behan M.Y., Baloch M.H.

Performance efficiency of two inch hydrocyclone has been investigated, using the Nagar Parker china clay. Raw china clay was initially washed with tap water and -75 ?m size fraction was separated through wet sieving. Washed china clay of -75 ?m was used as feed sample in hydrocyclone tests. Solids concentration in slurry was kept as 2.5%. 45 tests were conducted with different combinations of pressure, vortex finder and spigot. Three sizes of spigot viz. 3.2, 2.2 and 1.5mm and three sizes of vortex finder viz. 7.00, 5.5 and 3.00mm were used. Hydrocyclone rig was operated at five different pressures viz. 20, 30, 40, 50 and 60 psi in conjunction with various combinations of vortex finder and spigot. Laser light scattering technique was used for particle size analysis of O/F (Overflow) and U/F (Underflow) products. Separation efficiency of the hydrocyclone, for various combinations of Vortex Finder, Spigot and operating pressure, was determined for two size fractions, i.e. less than ten micron and less than twenty micron, present in O/F and U/F products. From the results it was concluded that the best separation efficiency of 2 inch hydrocyclone is achieved by using the vortex finder of 7.0mm size and spigot of 1.5mm size. It was also concluded that the separation efficiency of the hydrocyclone decreases by increasing the pressure.

6

Authors: Memon A.A., Hussain I., Daudpoto J.

To investigate the running characteristics of a switched reluctance motor, the static characteristics and related input data tables are required. The static characteristics comprise of flux linkage, co-energy and static torque characteristics. The co-energy and static torque are calculated once data of magnetization characteristics is available. The data of co-energy is required for the calculation of static torque characteristics. The simulation model includes the data of static characteristics for prediction of the instantaneous and steady state performance of the motor. In this research a computer based procedure of experiments is carried out for measurement of the magnetization characteristics. For every set of measurements, the removal of eddy current is carefully addressed. The experiments are carried out on an existing 8/6 pole rotary switched reluctance motor. Additionally, the instantaneous phase current, instantaneous torque and flux waveforms are produced by using linear, which is by default and spline data interpolation separately. The information obtained from theses simulation results will help in an improved simulation model for predicting the performance of the machine.

6

Authors: Dayo K.,Memon T.D.

In this paper, performance and area of conventional FIR (Finite Impulse Responce) filters versus ternary sigma delta modulated FIR filter is compared in FPGA (Field Programmable Gate Arrays) using VHDL (Verilog Description Language). Two different approaches were designed and synthesized at same spectral performance by obtaining a TIR (Target Impulse Response). Both filters were synthesized on adaptive LUT (Look Up Table) FPGA device in pipelined and non-pipelined modes. It is shown that the Ternary FIR filter occupies approximately the same area as the corresponding multi-bit filter, but for a given specification, the ternary FIR filter has 32% better performance in non-pipelined and 72% in pipelined mode, compared to its equivalent Multi-Bit filter at its optimum 12-bit coefficient quantization. These promising results shows that ternary logic based (i.e. +1,0,-1) filters can be used for huge chip area savings and higher performance.

8

Authors: Folino G., Shah A.A., Krasnogor N.

MC-PSC (Multi-Criteria Protein Structure Comparison) is one of the GCAs (Grand Challenge Applications) in the field of structural proteomics. The solution of the MC-PSC grand challenge requires the use of distributed algorithms, architectures and environments. This paper is aimed at the analysis of the scalability of our newly developed distributed algorithm for MC-PSC in the grid environment. The scalability in the grid environment indicates the capacity of the distributed algorithm to effectively utilize an increasing number of processors across multiple sites. The results of the experiments conducted on the UK's NGS (National Grid Service) infrastructure are reported in terms of speedup, efficiency and cross-site communication overhead.

8

Authors: Naleer H.M.M., Lu Y., Shah F.

The face hallucination research, in past ten years, has proposed a number of human face hallucination techniques. The face hallucination method does not follow the automatic face alignment in their experimental stages. In other words, these methods are not adequate for real world setting. Mainly some factors affect the final results of such methods, such as face pose, alignment, and lighting correction. Furthermore, the experimental images are aligned manually, and it may neither be accurate, nor added to the frame work. The main consideration in this paper is, how to produce the hallucinated human face image from single input low resolution image, using two step example base learning method with consideration of face pose and alignment in automatic frame work. We propose that the novel human face hallucination automatic frame work is excellent agreement with real world input low resolution images.

8

Authors: Memon I.A., Kalhoro M.S., Payne A.

Change blindness is the incapability of the brain to detect substantial visual changes in the presence of other visual interruption. The objectives of this study are to examine the EEG (Electroencephalographic) based changes in functional connectivity of the brain due to the change blindness. The functional connectivity was estimated using the wavelet-based MSC (Magnitude Square Coherence) function of ERPs (Event Related Potentials). The ERPs of 30 subjects were used and were recorded using the visual attention experiment in which subjects were instructed to detect changes in visual stimulus presented before them through the computer monitor. The two-way ANOVA statistical test revealed significant increase in both gamma and theta band MSCs, and significant decrease in beta band MSC for change detection trials. These findings imply that change blindness might be associated to the lack of functional connectivity in gamma and theta bands and increase of functional connectivity in beta band. Since gamma, theta, and beta frequency bands reflect different functions of cognitive process such as maintenance, encoding, retrieval, and matching and work load of VSTM (Visual Short Term Memory), the change in functional connectivity might be correlated to these cognitive processes during change blindness.

8

Authors: Syed Uzma, Jhatial R.A.

Fabric properties such as pilling and abrasion resistance and tensile strength vary when greige fabric is processed further. The quality of dyed fabric depends on the quality of greige fabric. Cotton Plain and Twill weave fabrics were woven at three different warp yarn tension and then dyed using monochlorotriazine, Drimerene Red Cl-5B dye gives difference in fabric properties. The ASTM, American International Standards were used to determine the greige and dyed fabric properties. It has been observed fabric woven at proper loom setting or warp yarn tension have high strength, less pilling and abrasion tendency as compared to fabric woven at variant warp yarn tension. Moreover, fabric tenacity is decreased after dyeing whereas, slight difference in pilling and abrasion values is observed after dyeing than that of greige fabric.

10

Authors: Hussain T., Shaikh G.Y., Shaikh S.A.

It is essential that rotating engines are assembled so that they are straight (straight-build) to satisfy the vibration and functional requirements of the engine. Geometric variations in different components can have a significant impact on the straight-build of an assembly. This paper considers the use of optimization methods to take account of these geometric variations. Five assembly-optimization methods for the straight build of an assembly are investigated with the aid of a connective assembly model that calculates the variation propagation in the assembly. The optimization methods used are; (i) minimizing the distances from component centres to table axis; (ii) minimizing the distance between actual and nominal component centres; (iii) minimizing the angular errors between actual and nominal planes; (iv) target-axis build assembly optimization; (v) changing-axis-build assembly optimization. Two 2D case-studies are investigated to analyse the suitability of the different optimization procedures. Simulation results show that optimization Procedures 1 and 3 have great potential to be applied to real assemblies.

10

Authors: Lashari J.H., Bhutto A., Abro Q. M.M.

This study identifies the status of postgraduate students at the master degree level regarding their degree completion in the three public sector universities at Jamshoro Education City. The status is identified by analyzing enrolment of the postgraduate and comparing it with rate of their degree completion. In addition, the paper also discusses their characteristics which lead them towards the degree completion. For this paper, enrolment of the postgraduate students at the master level is compared with the degree completion rate of 2008 academic session only. The result shows the obvious difference between enrolment and rate of the degree completion. In total 417 postgraduate students were enrolled in 2008 session, however, only 60 (14%) of students have completed their postgraduate degrees. Those who have completed their degrees, with respect to universities 6% students belong to US (University of Sindh), 22% belong to MUET (Mehran University of Engineering & Technology) and 8% students belong to LUMHS (Liaquat University of Medical & Health Sciences). The demographical data of the postgraduate students has also shown some variations like gender, age, employment, and financial resources. In addition, the research requirements also vary for different postgraduate students. The research requirements include lab based, field based and library based resources. The characteristics of the postgraduate students of three public sector universities including financial resources, employment status, and working organization also show differences with each-other in terms of the degree completion.

16

Authors: Yaqub M., Bukhari I.A., Ghani U.

The experience shows that fire-damaged concrete structures both technically and economically can be reinstated after fire due to high fire resistance and high residual strength. The residual strength of fire-damaged concrete structural member depends on the peak temperature reached during fire, fire duration and the distribution of temperature within the structural member. The assessment of the residual strength of post-heated concrete structural members in a professional way is a prime factor to take a decision about the reinstatement or demolition of fire-damaged structure. This paper provides an easy and efficient approach to predict the residual strength of reinforced concrete columns based on the estimated temperature which may have occurred within the concrete cross-section during a fire. A finite element model was developed to evaluate the distribution of temperature within the cross-section of the reinforced concrete columns. Twelve reinforced concrete square columns were heated experimentally up to 500°C at 150°C/hour. A comparison of the experimental temperature values of the tested columns was made with the model results. A good agreement was found between the experimental and the finite model results. Based on the temperature distribution obtained from the finite element model, the residual strength of concrete and reinforcement could be evaluated by using the relationships for concrete, steel and temperature proposed by various researchers.