Mehran University Research Journal of Engineering and Technology

4

Authors: Mukhtiar Ahmed Mahar, Abdul Sattar Larik, Syed AsifAli Shah

AC-AC conversion is obtained with the help of Cyclo-converters, DC Link converters and AC Voltage Controllers. AC voltage controllers are also referred to as voltage regulators. Main issue concerned to these converters is that they generate harmonics due to periodic variable structure system. The generated harmonics create disturbances and degrade the performance of converter. The power factor of supply side is affected due to these harmonics. This paper focuses on source side power factor of ac voltage controllers under nonsinusoidal conditions. In order to observe the power factor, measurement tool of power factor and simulation model of ac voltage controller is also developed in MATLAB software.

6

Authors: Awais Khatri, Mazhar Hussain Peerzada

Pad steam process of dyeing cotton with reactive dyes is known to give lower levels of dye-fixation on the fiber because of excessive dye-hydrolysis. This research presents improved reactive dye-fixation in padsteam process of dyeing cotton found in an effort of using biodegradable organic salts to improve the effluent quality. The CI Reactive Blue 250, a bissulphatoethylsulphone dye and the Tetrasodium N, Nbiscarboxylatomethyl- L-Glutamate, a biodegradable organic salt, were used. The new dye-bath formulation using the organic salt gave more than 90% dye-fixation. Traditional pad-steam process of dyeing cotton with reactive dyes requires the use of inorganic electrolyte, sodium-chloride, and alkali, sodium-carbonate, to ensure effective dye consumption and fixation. These inorganic chemicals when drained generate heavy contents of dissolved solids and oxygen demand in the effluent leading to environmental pollution. Thus, Tetrasodium N, N-biscarboxylatomethyl-L-Glutamate was used in place of inorganic electrolyte and alkali to improve effluent quality. A significant increase in dye-fixation and ultimate color-yield was obtained with same colorfastness properties of the dyed fabric comparing to the traditional pad-steam dye-bath formulation.

6

Authors: Hassan Ali Durrani, Muhammed Ibrahim Panhwar , Rafique Akthar Kazi

Re-refining of vehicle waste lubricating oil by solvent extraction is one of the efficient and cheapest methods. Three extracting solvents MEK ((Methyl-Ethyl-Ketone), 1-butanol, 2-propanol were determined experimentally for their performance based on the parameters i.e. solvent type, solvent oil ratio and extraction temperature. From the experimental results it was observed the MEK performance was highest based on the lowest oil percent losses and highest sludge removal. Further, when temperature of extraction increased the oil losses percent also decreased. This is due to the solvent ability that dissolves the base oil in waste lubricating oil and determines the best SOR (Solvent Oil Ratio) and extraction temperatures.

6

Authors: Zubair Ahmed Memon, Mohammad Aslam Uquaili, Mukhtiar Ali Unar

With the development of modern industrial technology a large number of non-linear loads are used in power system, which causes harmonic distortion in the power system. At the same time the power quality and safe operation becomes inferior. Therefore mitigation of harmonics is very necessary under the situation. This paper presents the design of two passive filters to reduce the current harmonics produced by nonlinear loads in industrial power system. Matlab /simlink software has been used for the simulation purpose. The results have been obtained with and without installation of filters and then it is observed that after installation of filters harmonics of the current are reduced and power factor is improved.

8

Authors: Atif BinMansoor, Zohaib Khan, Shoab Ahmed Khan

Internet is a widely used medium for transfer of information due to its reach and ease of availability. However, internet is an insecure medium and any information might be easily intercepted and viewed during its transfer. Different mechanisms like cryptology and steganography are adopted to secure the data communication over an inherently insecure medium like internet. Cryptology scrambles the information in a manner that an unintended recipient cannot easily extract the information, while steganography hides the information in a cover object so that it is transferred unnoticed in the cover. Encrypted data may not be extracted easily but causes a direct suspicion to any observer, while data hidden using steganographic techniques go inconspicuous. Cryptanalysis is the process of attacking the encrypted text to extract the information, while steganalysis is the process of detecting the disguised messages. In literature, both cryptology and steganography are treated separately. In this paper, we present our research on an improved data security paradigm, where data is first encrypted using AES (Advanced Encryption Standard) and DES (Data Encryption Standard) cryptology algorithms. Both plain and encrypted data is hidden in the images using Model Based and F5 steganographic techniques. Features are extracted in DWT (Discrete Wavelet Transform) and DCT (Discrete Cosine Transform) domains using higher order statistics for steganalysis, and subsequently used to train a FLD (Fisher Linear Discriminant) classifier which is employed to categorize a separate set of images as clean or stego (containing hidden messages). Experimental results demonstrate improved data security using proposed CRYPTO-STEG approach compared to plain text steganography. Results also demonstrate that the Model Based steganography is more secure than the F5 steganography.

8

Authors: Zubair Ahmed Memon, Mohammad Aslam Uqaili, Mukhtiar Ali Unar

Power quality standards (IEEE-519) require to limit the total harmonic distortion within satisfactory range caused by power electronic based devices. Our work deals with the design of hybrid active filter to reduce current perturbations produced by power electronics based devices. The Instantaneous Active and Reactive Power Method (pq) is used to perform the identification of disturbing currents. The pq algorithm creates a reference current, whereas, this reference current is tracked by the current of the voltage source converter. The currents of the voltage source converter are controlled by hysteresis controller. Simulation results showed that the hybrid active filter can compensate the harmonic currents effectively and improve power quality.

10

Authors: Sania Bhatti , Manzoor AhmedHashmani , Naheed Shaikh

An Expert System is a computer program that simulates the human intelligence and behaviour in specific and limited domains. It is used to solve problems with tricks, shortcuts and heuristics i.e. rules of thumb. Checking a Plan (Map) to verify its compliance with building bylaws is a complex task mainly due to various rules and the exceptions to those rules. Humans are prone to make errors in such situations. Due to the problems faced by Building Control Department, HDA ( Hyderabad Development Authority) there is a strong need to develop a computerized system. In this research we have developed a prototype named as ESBBC (Expert System for Building Bylaws Compliance) for HDA that can help in their building plan checking system. The proposed solution is merging three frameworks, i.e. Java an OOP (Object Oriented Programming) language, Prolog- a rule based language and MS Access- for database. The solution is fulfilling the three main requirements of the HDA, i.e. Determination of whether a particular plan is in compliance with predefined building bylaws or not. (2) Offering search facility. (3) Maintaining records of plans which are entered for compliance checking. We have checked plans of 20 properties according to HDA building regulations using ESBBC and presented their results. The results show that ESBBC has capability to identify errors made by humans.

10

Authors: Imdadullah Siddiqui, Muhammad Hassan Agheem, Abdul Salam Soomro

The Meting-Jhimpir coalfield covers an area of about 90 square kilometers. The coal in the Meting- Jhimpir area was deposited in Early Eocene age, in the east of Karachi. The coal is enriched in Fe, Zn, Pb, Ni, Cu, Cr, Sb, As, Co, Cd, Mn, Na, K, Ca and Mg. The study also shows that in Meting-Jhimpir coal quartz is dominant mineral and calcite and dolomite as accessory minerals. The comparison of studied coal with Clarke values shows that the coal is slightly enriched with Co, Cr, As, Ca, Mg, and U and Cu, K, Na, Ni, Pb and Zn are depleted.

10

Authors: Imran Ali Jokhio, Sana Hoor Jokhio, Faisal Karim Shaikh

The growing popularity of RFID (Radio Frequency Identification) systems cannot be overlooked due to their wide range of application areas. However, some RFID applications face security and privacy threats due to the exposure of tags over wider distances. There are security methods but these can lack security and scalability when authenticating RF tags in MORIS (Multi Organizational RFID System). RFID systems operating within a single domain have only security and privacy issues due to the security method on tags, but in a multi-organizational system there are even more security and privacy issues in the system architecture rather than just in the security method on tag side. In this paper, we have designed a broker service to EPC (Electronic Product Code) system architecture for secure and confidential data management of the RFID data events. Secure and confidential authentication broker service is an extension to the EPC network architecture for a MORIS. The central authentication broker service ensures to avoid illicit access to the confidential RFID tag's data such as EPC code, whilst managing a large-scale authentication data to ensure secure and deterministic response to the authentic entities of the system.

14

Authors: Zeeshan Ali Memon, Mukhtiar Ali Unar, Dur Muhammad Pathan

MPC (Model Predictive Control) techniques, with constraints, are applied to a nonlinear vehicle model for the development of an ACC (Adaptive Cruise Control) system for transitional manoeuvres. The dynamic model of the vehicle is developed in the continuous-time domain and captures the real dynamics of the sub-vehicle models for steady-state and transient operations. A parametric study for the MPC method is conducted to analyse the response of the ACC vehicle for critical manoeuvres. The simulation results show the significant sensitivity of the response of the vehicle model with ACC to controller parameter and comparisons are made with a previous study. Furthermore, the approach adopted in this work is believed to reflect the control actions taken by a real vehicle.