Mechanical Engineering

Investigation of combustion properties of five selected indigenous fuel wood samples was carried out in this study. Combustion properties such as high heating value (HHV), proximate and ultimate analysis, density/specific gravity, thermal conductivity, particle size, flame temperature and porosity were obtained using standard experimental procedures for the selected wood samples. The higher heating values of the five wood samples varied from 2282.117 – 4461.9326 Kcal/kg (9.55 – 18.682 MJ/kg). These values were better than some reported values in literature. The flame temperature for the five samples ranged from 531 – 700 oC. Proximate analysis results revealed that the ash content for the five samples varied from 6.79 to 48.24 %, fixed carbon varied from 9.45 to 21.30 %, volatile matter varied from 64.23 to 66.64 %, moisture content varied from 3.01 to 5.63 %. Ultimate analysis result revealed that hydrogen, oxygen, and nitrogen contents also range from 3.1128 to 5.5642 %, 22.9981 to 40.6901 % and 0.3630 to 0.65221 % respectively. Some of the values of density/specific gravity, porosity, thermal conductivity, particle size obtained were within values reported by other researchers. The result of the fuel rating properties revealed that African Prosopis has the best fuel property with fuel rating of 1.68 and Quassia undulate the worst with fuel rating of 3.68 compared to the other samples.

Quality refers to an equilibrium level of functionality possessed by a product or service based on the producers capability and customers need. The aim of any manufacturing concern is to increase the production and to bring down the production cost without compromising on quality. This can be achieved through the implementation of innovative managerial techniques. Theory of constraints is an innovative tool for quality and productivity improvement. A significant challenge in implementing the theory of constraints in robotic operation is the complex and re-entrant nature of the manufacturing process. This paper deals with the problem of improving quality in robotic work cells that repetitively handle several products of similar characteristics. The theory of constraint is proposed to increase the quality and throughput rate of a robotic work cell by identifying its bottlenecks

An analytical study is performed to study the effects of thermal radiation and chemical reaction on unsteady free convection and mass transfer of a viscous incompressible fluid past an accelerated infinite isothermal vertical plate in the presence of magnetic field. The fluid considered here is a gray, absorbing/ emitting radiation but a non-scattering medium. It is assumed that the effect of viscous dissipation is negligible in the energy equation and there is a first order chemical reaction between the diffusing species and the fluid. The dimensionless governing coupled linear partial differential equations are solved using the Laplace transform technique. The influence of the various parameters, entering into the problem, on the velocity field and temperature field is extensively discussed with the help of graphs.

A second order process of 164.5 seconds settling time is controlled using a PDF controller (through simulation). The controller is tuned by minimizing the sum of square of error of the control system using MATLAB. Functional constraints are imposed on the maximum percentage overshoot, settling time and stability condition. The result was reforming the process slow response and producing a closed-loop control systems of a maximum percentage overshoot less than 2 % and a settling time less than 0.6. The performance of the tuned-PDF controlled process is compared with that tuned using the ITAE standard forms.

All welding processes are used with the aim of obtaining a welded joint with the desired weld-bead parameters, excellent mechanical properties with minimum distortion. The welding input parameters play a significant role in obtaining excellent mechanical properties with minimum distortion to get a desired weld bead parameters. Usually, the desired welding parameters are determined using traditional methods like welder’s experiences, charts and handbooks (preferred values) which are simple and inexpensive. But this does not ensure that the selected welding parameters result in satisfactory welding and this method is not applicable to new welding process. To achive desired weld bead parameters different models were developed to correlate input variables with output variables. Mathematical models to specify the relationship between the input variables and output parameters can be used for optimization. Design of Experiment (DoE) technique has been used to carry out such optimization. Computational network & evolutionary algorithms have also grown rapidly and been adapted for modeling and optimization of welding process parameters to achieve desired properties in the welded joint. In this paper a comprehensive literature review of the application of these techniques is presented. This review shows the correlation and modeling between the input welding process parameters and the output weldment characteristics. The paper also presents the optimization of the different welding processes through the mathematical models and evolutionary algorithm. The use of mathematical models and evolutionary algorithm for the optimization of the different welding processes is discussed in this paper.

A thick-walled 90° elbow pipe is of particular interest due to its frequent usage in industrial systems such as chemical processing plants and petroleum refineries. Elastic stress analysis of thick walled pipe elbows using finite element computer software, such as ABAQUS was investigated. The current study shows that the stress level is influenced by the effects of the ratios of bend radius to pipe mean radius (R/ ) and mean radius to wall thickness ( /t) and value of internal pressure. The investigation is limited to include the elastic stresses due to internal pressure and stress variation which was found to be similar to that of a theoretical study reported in the literature. The stress along a thick-walled 90° elbow pipe with the increase in the inner radius, thickness and pressure increases the stress. Based on the variance analysis, the predictive models in this study are believed to produce values of the elastic stress of a thick-walled 90° elbow pipes close to those readings recorded numerically with a 96.5% confident interval.

Service sectors such as banking, healthcare, hospitals, retail etc in India are facing an immense pressure from customers in providing the services at a faster rate with a greater quality. At present, service sectors are increasingly becoming a customer centric service provider. Integration of Lean and Six Sigma is a kind of quality and time enhancing strategy that can help service sectors to win the customer loyalty and growth. However, Lean Six Sigma itself is only not enough to meet the rapidly increasing competition, but also, the integration between Lean Six Sigma and the knowledge management is very important. The study examines the achievable benefits by the use of knowledge management and also gives the critical analysis of the impact of Lean Six Sigma in service sectors and the customer satisfaction by providing the products and services at the best quality within the least time (customer available time). The article provides “5 I” (5 I – Identify, Investigate, Improve, Implement and Impart) approach with Lean and Six Sigma combination and the tools and techniques to improve the efficiency and effectiveness of the services and products that provide. In this article “5 I” approach explains the use of tools and methodology to be adopted to streamline the process and also to improve the quality in the output. The 5I approach with the tool box explained in the article interim will help in growth of service sectors in India in achieving effectiveness and efficiency. It also provides the customer satisfaction by providing the services faster, greater quality and lesser cost.

One of the most important factors for agricultural mechanization is management of repair and maintenance costs. Today, tractor is one of the main sources of power in agriculture. The engine overhaul cost is the most rates of repair and maintenance costs. Suitable and high quality engine oil consumption is a more effective factor on engine life increasing. The Nano-science is a new effective method to improving the quality of engine oil and controlling of costs. This study was carried to evaluate the impact of Nano-diamond as an engine oil additive on increasing the oil quality and wearing reduction in the engine oil components. For this purpose, 10 Massey Ferguson 399 tractors were selected from the common tractors in Iran and were classified in two groups. The Nano-diamond as an oil additive material was added to engine oil in one group and was used pure engine oil (without adding any additive) in other one. Then the oil sampling were carried on all tractors engine oil at 50, 100 and 120 hours service time durations and elemental analysis were completely performed on samples. The data were analyzed by SPSS software. Results showed a significant difference at 5% level, between the two groups based on the life oil additives as well as the quantity of erosion particles. The results showed that it is effective to increasing of engine lubricant oil quality as well as reducing of erosion particles quantity, when this additive is used whit 1% concentration based on weight in MF 399 engine lubricant oil tractor. Additionally, resulting from hard Nano-diamond structure, some of the large ferrous particles observed that their quantities have been decreased gradually.

Evaluation of 20 min. shot peening surface treatment on fatigue strength of 6063-T6 Al allay is presented under 3.5% NaCl solution from one day, one week and one month under room temperature and stress ratio R= -1. The results show that the shot peening has strong effect on the fatigue strength at 107 cycles for corroded specimens. In case of shot peening ,only 17.5% loss in fatigue strength even after submerging for one week compared with 60% of the fatigue strength was reduced in case of un shotted specimen . But for one month pre – corroded specimens, the fatigue strength was reduced by 64% in corrosion environment while shot peening improved the above reduction to be about 44%.

Environmenatal factors such as climate change, gradual decrease in water resources and threatened habitants prompted the need to monitor our environment and implement better policies to protect it, thus monitoring soil pF (potential factor) values become increasingly important for environmental monitoring. The commonly available instrument(tensiometer) do not measure the range of available moisture in all soil types rather measures soil water suction. The need to measure the range of available moisture in all soil types with accuracy led to the modification of tensiometer for satisfactory laboratory results. Due to the shortcomings associated with tensiometer readings, the pressure membrane apparatus is an important instrument for optimizing irrigation and erosion prediction models.This pressure membrane with extractor has two main components:a porous plate with air entry pressure and a sealed pressure cell. The soil from which pF value was to be determined was placed in a chamber in which the pressure increased above atmospheric pressure. The side of the chamber which supports the soil consists of a pressure relief valve supported on a pressure hose. This is to ensure that the extractor chamber was not over-pressurized. The soil water potential with the corresponding mositure contents of four soil samples: A (clay soil), B(loamy soil), C (sandy soil) and D (silt) obtained from different locations were determined using pressure membrane apparatus. At a potential of 104hPa, samples A,B,C,D showed moisture content of 0.05,0.25,0.30, and 0.45cm3/cm3respectively. From the obtained results, at potentail close to zero, sandy soil is close to saturation and moisture held in the soil, primarily by capillary forces. From the laboratory analysis, moisture content decreases with high moisture cohesion.