Mehran University Research Journal of Engineering and Technology

6

Authors: Saleem Y., Hayat F., Iqbal A.

Telecommunication industry is growing and different services are rapidly introduced by different competitors to attract the users. Speech communication and its quality conservation is the most prevalent and common service provided by almost all companies. The objective of this project is the development of a LPC (Linear Predictive Coding) based voice coder. Attributes for speech like pitch, voiced and unvoiced decision and silence were extracted and speech was modeled using LDR (Levinson Durbin Recursion) and SDA (Steepest Descent Algorithm). LPC filter is analyzed and its model is implemented. LPC's different attributes complexity, delay and bitrate are deliberated and tradeoffs are highlighted. The results were analyzed and quality of speech was determined using spectrograph and by listening to the synthesized speech. At the end quality of original and synthesized speech is discussed and shown graphically and a soft comparison between both above mentioned technique is also added

8

Authors: Memon A.A., Memon Z.A., Aamir R.R.

Our work is the small part of the smart grid system. This is regarding the check and balance of power consumption at the consumer level. It is a well known fact that the consumers are allocated a fixed load according to their requirement at the time of application for the electricity connection. When the consumer increases its load and does not inform the power company, the result is the overloading of the system. This paper presents a solution regarding distribution and load allocation to each customer. If the customer uses power greater than the load allocated, further power is not provided and consequently that appliance is not turned on unless the total load must not be decreased than the allocated load. This is achieved by designing a processor controlled system that measures the power on main line and also the power taken by each device. Now when a device is turned on, its power is measured by the controller and compares it with the main line power, and when the device consumes some power consequently main line power will also be increased thus this main line power is monitored and if it exceeds particular limit that device is turned off through its relay

8

Authors: Sahito A.R., Mahar R.B., Ahmed F.

Generation of methane from animal dung through AD (Anaerobic Digestion) is the most feasible way to get energy from it. Pakistan has about 70 million heads of cattle and buffalos, and about 90 million heads of sheep and goats. The dung from these animals can overcome the energy crisis and can fulfill the future energy demands of Pakistan. In present study, buffalo dung is used as the substrate for anaerobic digestion process, whereas the production of methane was analyzed as the function of buffalo dung to water ratio. Six batch reactors with different buffalo dung to water ratios were incubated in the AMPTS (Automatic Methane Potential Test Setup) for 51 days. The highest methane production was observed from the buffalo dung to water ratio of 2.0 i.e. 226.4 NmL/gVS loss , followed by 198.6 NmL/ gVS loss from the buffalo dung to the water ratio of 1.0. The suitable hydraulic retention time of the anaerobic digester treating buffalo dung was observed as 20 days

8

Authors: Rafique S., Shah S.A.

Over the past few years, remarkable developments in piezoelectric materials have motivated many researchers to work in the field of vibration energy harvesting by using piezoelectric beam like smart structures. This paper aimed to present the most recent application of a dual function piezoelectric device which can suppress vibration and harvest vibration energy simultaneously and a brief illustration of conventional mechanical and electrical TVAs (Tuned Vibration Absorber). It is shown that the proposed dual function device combines the benefits of conventional mechanical and electrical TVAs and reduces their relative disadvantages. Conversion of mechanical energy into electrical energy introduces damping and, hence, the optimal damping required by this TVA is generated by the energy harvesting effects. This paper presents the methodology of implementing the theory of 'electromechanical' TVAs to suppress the response of any real world structure. The work also illustrates the prospect of extensive applications of such novel "electromechanical" TVAs in defence and industry. The results show that the optimum degree of vibration suppression of an electronic box is achieved by this dual function TVA through suitable tuning of the attached electrical circuitry

10

Authors: Rajper A.H., Maganhar A.L., Shah S.A.

Development of composite from natural fiber for lower structural application is growing for long-term sustainable perspective. Cotton fiber composite material has the added advantages of high specific strength, corrosion resistance, low cost and low weight compared to glass fiber on the expense of internal components of IC engines. The primary aim of the research study is to examine the effect of the cotton fiber on mechanical properties of lower structural applications when added with the polyester resin. In this paper composite material sample has been prepared by hand Lay-Up process. A mould is locally developed in the laboratory for test sample preparation. Initially samples of polyester resin with appropriate ratio of the hardener were developed and tested. At the second stage yarns of cotton fiber were mixed with the polyester resin and sample specimens were developed and tested. Relative effect of the cotton as reinforcing agent was examined and observed that developed composite specimen possess significant improvement in mechanical properties such as tensile strength was improved as 19.78 % and modulus of elasticity was increased up to 24.81%. Through this research it was also observed that developed composite material was of ductile nature and its density decreases up to 2.6%. Results from this study were compared with relevant available advanced composite materials and found improved mechanical properties of developed composite material

12

Authors: Ghani U., Ali S., Ghaffar A.

Bridge pier scouring is an important issue of any bridge design work. If it is not taken into account properly, then results will be disastrous. A number of bridges have failed due to clear water local scouring of piers. This research paper presents a numerical model study in which an attempt has been made to explore the flow variables which exist in and around a scoured bridge pier. A finite volume based model of bridge pier was developed using 3D (Three Dimensional) numerical code FLUENT and GAMBIT. After validation process, different discharge values were considered and its impact on three dimensional characteristics of flow such as stream-wise velocities on longitudinal and transverse sections, turbulance circulation cells, and boundary shear stresses was investigated. It was observed that increasing the discharge results in more turbulance around the pier on its downstream side and turbulence properties are intensified in such a situation. However, the primary velocities on the downstream side remain almost unchanged. The results have been presented in the form of contours, vector of primary velocities and x-y plots of bed shear stresses. This study can be used for enhanced understanding of flow features and improvement of formulae for prediction of scour holes around piers

16

Authors: Khan U.A., Jokhio F.A., Sadhayo I.H.

This paper proposes a RL (Reinforcement Learning) based DPM (Dynamic Power Management) technique to learn timeout policies during a visual sensor node's operation which has multiple power/performance states. As opposed to the widely used static timeout policies, our proposed DPM policy which is also referred to as OLTP (Online Learning of Timeout Policies), learns to dynamically change the timeout decisions in the different node states including the non-operational states. The selection of timeout values in different power/performance states of a visual sensing platform is based on the workload estimates derived from a ML-ANN (Multi-Layer Artificial Neural Network) and an objective function given by weighted performance and power parameters. The DPM approach is also able to dynamically adjust the power-performance weights online to satisfy a given constraint of either power consumption or performance. Results show that the proposed learning algorithm explores the power-performance tradeoff with non-stationary workload and outperforms other DPM policies. It also performs the online adjustment of the tradeoff parameters in order to meet a user-specified constraint