Mechanical Engineering articles list

The identification of isomorphism in epicyclic gear trains has been found a lot of attention by researchers for the last few years. Various methods have been suggested by different authors for the detection of isomorphism in planer kinematic chains and epicyclic gear trains (EGTs), but everyone has found some difficulties to address new issues. In this paper, a modified path matrix approach was presented in order to compare all the distinct geared kinematic mechanisms. A new method based on the matrix approach and corresponding train values is required to identify isomorphism among epicyclic gear trains and their mechanisms. The proposed method was examined on the basis of various examples from four-link, five-link, six links, and eight-link one-degree-of-freedom EGTs and six links two-degree-of-freedom EGTs. All the examples have been found satisfactory results with existing literature.

JIYAUL MUSTAFA

As one of the flow-based passive sorting, the hydrodynamic filtration using a microfluidic-chip has shown to effectively separate into different sizes of subpopulations from cell or particle suspensions. Its model framework involving two-phase Newtonian or generalized Newtonian fluid (GNF) was developed, by performing the complete analysis of laminar flow and complicated networks of main and multiple branch channels. To predict rigorously what occurs in flow fields, we estimated pressure drop, velocity profile, and the ratio of the flow fraction at each branch point, in which the analytical model was validated with numerical flow simulations. As a model fluid of the GNF, polysaccharide solution based on Carreau type was examined. The objective parameters aiming practical channel design include the number of the branches and the length of narrow section of each branch for arbitrary conditions. The flow fraction and the number of branches are distinctly affected by the viscosity ratio between feed and side flows. As the side flow becomes more viscous, the flow fraction increases but the number of branches decreases, which enables a compact chip designed with fewer branches being operated under the same throughput. Hence, our rational design analysis indicates the significance of constitutive properties of each stream.

Myung-Suk Chun

Human bone marrow-derived mesenchymal stem cells (hMSCs) consist of heterogeneous subpopulations with different multipotent properties: small and large cells with high and low multipotency, respectively. Accordingly, sorting out a target subpopulation from the others is very important to increase the effectiveness of cell-based therapy. We performed flow-based sorting of hMSCs by using optimally designed microfluidic chips based on the hydrodynamic filtration (HDF) principle. The chip was designed with the parameters rigorously determined by the complete analysis of laminar flow for flow fraction and complicated networks of main and multi-branched channels for hMSCs sorting into three subpopulations: small (<25>40 μm) cells. By focusing with a proper ratio between main and side flows, cells migrate toward the sidewall due to a virtual boundary of fluid layers and enter the branch channels. This opens the possibility of sorting stem cells rapidly without damage. Over 86% recovery was achieved for each population of cells with complete purity in small cells, but the sorting efficiency of cells is slightly lower than that of rigid model particles, due to the effect of cell deformation. Finally, we confirmed that our method could successfully fractionate the three subpopulations of hMSCs by analyzing the surface marker expressions of cells from each outlet.

Myung-Suk Chun

During this research work, a theoretical study was done to compare the boiler efficiency by using two different fuels, i.e. commercial sawdust briquette and biomass briquette prepared using 850 μ coconut leaves, with sawdust as the binder. For preparing the biomass briquettes to leave of coconut were gathered, dried, milled, and sieved and sizes of 850μ were selected. The sized coconut leaves were then mixed in the company of sawdust that worked as a binder in 1:2 ratios, and compressed by means of a piston-type briquette machine, which was fabricated for the same. Ultimate and proximate analyses were carried out on the biomass briquette to determine their various compositions. Results from analysis were used to calculate the boiler efficiency by the indirect method using Indian Standard Boiler Efficiency IS 8753. Results from the analysis showed that boiler efficiency by indirect method for commercial sawdust briquette is 68.80% and boiler efficiency by indirect method for coconut leaves of 850μ, with sawdust as a binder is 61.17%. The reason for higher boiler efficiency for commercial sawdust briquette is due to its higher calorific value (4451.37KCal/gm) when compared to that coconut leaves briquette made from 850μ size with sawdust as a binder (3672.45KCal/gm). From proximate and ultimate analysis, the results showed a reduction in ash content percentage, moisture content, and rise in volatile matter percentage, when the comparison was along with the marketable sawdust briquette, which is of considerable significance. Additional properties akin to the percentage of hydrogen, fixed carbon, sulfur, nitrogen, and oxygen were roughly the same as that of the commercially available sawdust briquettes. After calculating the boiler efficiency of the two biomass briquettes, coconut leaves with sawdust as binder exhibited the most optimistic trait and as it is more easily and readily available, thus making it more economically viable.

Dr.Deepak KB

A Man-Machine System means an activity occurring/occurred with the involvement of a human being with the help of some tools used to interact with the material. In small foundries, the moulding process is manual & labours have to work in different psychological moods, stress, and strain, without training on ergonomic posture, in different environmental factors such as temperature, vibrations, noise dust which affects productivity and also the amount of human energy input to produce the component. This paper makes an attempt to develop a mathematical model to relate productivity with various parameters and identify the most sensitive parameter to control productivity.

Rahul Bachute

In this paper, an approach for formulation of generalized field data based model for cylinder head moulding operation. The aim of field data based modeling for cylinder head moulding operation is to improve the output by correcting or modifying the inputs. The goal of the research is to reduce human energy input required while performing cylinder head moulding operation. With the reduction in human energy input, automatically, the productivity of the process will also increase. The study identifies important ergonomic and other work environment related parameters which affect productivity. The identified parameters are properties of sand, physical dimensions of tools, energy outflow of workers, anthropometric data of the workers, working conditions like relative humidity, ambient temperature. Out of all the variables, responses and causes are identified. After dimensional analysis relationship between the dependent and independent parameters, a mathematical model is established having a relationship between output parameters and input. To get the optimized values model is optimized using the optimization technique. Sensitivity analysis is a tool which can be used to find out the effect of input one parameter over the other. The model will be useful for an industrialist to select optimized inputs so as to get targeted responses.

Rahul Bachute

This mathematical model forms machine cells, optimises the costs of unassigned machines and components, and designs the shop floor cell layout to have minimal movement of materials. The complete similarity measure algorithm forms machine cells and part families in a refined form. Later, exceptional elements are eliminated in the optimisation model by using machine duplication and sub-contracting of parts. Then the shop floor layout is designed to have optimised material movements between and within cells. An evaluation of the cell formation algorithm’ performance is done on the benchmark problems of various batch sizes to reveal the process’s capability compared with other similar methods. The data of machining times are acquired and tabulated in a part incidence matrix, which is used as input for the algorithm. The results from the linear programming optimisation model are that costs are saved, machines are duplicated, parts are sub-contracted, and there are inter- and intra-cellular movements. Finally, the output of the inbound facility design is the floor layout, which has machine cell clusters within the optimised floor area.

S RAMESH

This proposed work is used to optimize the costs of exceptional elements of machine cells for a variety of components in changing environments to have reduced material movements in cell layout. The exceptional ele¬ments are eliminated in the optimization model by doing machine duplication and part subcontract. Then the shop floor layout is designed to have optimized material movements between cells and within a cell. The result of a linear programming optimization model is cost savings, machines duplicated, parts subcon¬tracted, inter intracellular movements. Finally, the output of the inbound facility design is the floor layout which has machine cell clusters with optimized floor areas. The optimization model is provided with budg¬etary constraints for duplication and the economic tradeoff between machine duplication and part subcontract. Cell layout is prepared to reveal the saving in floor area and material movement lengths than in process layout with the help of distance matrix and dimensions of cells.

S RAMESH

The presented mathematical model is used to form machine cells, optimize costs of exceptional elements and design the shop floor layout for various demands of components. The complete similarity measure algorithm forms machine cells and part families in a refined form. Later, exceptional elements are eliminated in linear programming optimization model by using machine duplication and part subcontract. Then the shop floor layout is designed to have optimized material movements between cells and within a cell. The performance evaluation of cell formation algorithm is done on case studies of various batch sizes to give the process capability compared with other similar methods. The result from a linear programming optimization model is cost savings, machines duplicated, parts subcontracted, inter intra cellular movements. Finally, the output of inbound facility design is the floor layout which has machine cell clusters with optimized floor area.

S RAMESH

The Cellular Manufacturing is adopted in batch type manufacturing industries nowadays for their production with increased productivity, less cost and time with effective control. The proposed optimization model is used to determine the cost of machine cells, i.e., machine duplication, part subcontract, inter intra cellular movements cost and cost of production associated with machine cell, such as machine reconfiguration and part inventory considering machine flexibility for various time periods. Initially, mathematical model is proposed to calculate machine cell cost with and without considering machine flexibility and then another lpp integer model is proposed to calculate the machine cell production and associated cost for the changes in time period, part type and volume considering machine flexibility. The manufacturing data in the incidence matrix and machine cell, part family data in the block diagonal form are given as input to the optimization programming language Cplex and the output are given for the two mathematical models. The data related to machine duplication, part subcontract, inter intra cellular movement; machine reconfiguration and part inventory are given. Two dimensional shop floor layouts are presented in rectilinear coordinates for all the problems for easy analysis of material movement length and shop floor area

S RAMESH

The Cellular Manufacturing is adopted in batch type manufacturing industries nowadays for their production with increased productivity, less cost and time with effective control. The proposed optimization model is used to determine the cost of machine cells, i.e., machine duplication, part subcontract, inter intra cellular movements cost and cost of production associated with machine cell, such as machine reconfiguration and part inventory considering machine flexibility for various time periods. Initially, a mathematical model is proposed to calculate machine cell cost with and without considering machine flexibility, and then another lpp integer model is proposed to calculate the machine cell production and associated cost for the changes in the time period, part type, and volume considering machine flexibility. The manufacturing data in the incidence matrix and machine cell, and part family data in the block diagonal form are given as input to the optimization programming language Cplex and the output is given for the two mathematical models. The data relating to machine duplication, part subcontract, inter intracellular movement; machine reconfiguration, and part inventory are given. Two-dimensional shop floor layouts are presented in rectilinear coordinates for all the problems for easy analysis of material movement length and shop floor area

S RAMESH

The share of renewable energy share in India's energy mix of India has been increasing recently owing to the promotion and implementation of various government policies that promote the use of renewable sources of energy, depleting fossil fuel levels, increasing fuel prices, and stringent laws for emission reduction worldwide. The increase in the use of solar-evacuated-tube-collector-based domestic water heating is the result of this transition from conventional to nonconventional sources of energy. The recent urban agglomeration is challenging to install these solar water heaters in every household because the roof space is limited. Space reduction can be achieved by reducing the collector area by varying the diameter of the evacuated tubes. This study used a single tube and tank arrangement model with a fixed inclination to achieve a thermosyphon effect in a solar water heating system with three different diameter configurations of 48 mm, 54 mm, and 72 mm, with a tube measuring 1800 mm in length. Thermal assessment of the thermosyphon-based evacuated tube-solar water heater using the ANSYS CFD simulation software involves measuring the temperature at three different positions in the tank to study the thermosyphon initialization. This study signifies that the 72-mm-diameter evacuated tube is more capable of initializing the thermosyphon effect in the system. Nevertheless, the final temperature of the system is better achieved in the 48-mm-diameter evacuated tube

Swapnil Ratnakar Mane

We present a series of large-eddy simulations to systematically investigate the impact of debris accumulation on the hydrodynamics and power production of a utility-scale marine hydrokinetic (MHK) turbine under various debris loads lodged on the upstream face of the turbine tower. The turbine blades are modeled using turbine resolving, actuator line, and actuator surface methods. Moreover, the influence of debris on the flow field is captured by directly resolving individual logs and employing a novel debris model. Analyzing the hydrodynamics effects of various debris accumulations, we show that an increase in the density of debris accumulation leads to more flow bypassing beneath the turbine blade. This, in turn, reduces the flow momentum that reaches the MHK blades at the lower depths, inducing significant fluctuation in power production. Further, it is shown that debris-induced turbulent fluctuations contribute to significant variability in the MHK turbine’s power production.

Hossein Seyedzadeh

Tidal and riverine flows are viable energy sources for consistent energy production. Installing and operating marine hydrokinetic (MHK) turbines requires assessing any potential impact of debris accumulation on turbine performance and sediment transport. More specifically, MHK devices may alter the natural sediment transport processes and cause debris accumulation, disrupting the natural sediment dynamic. In turn, these processes could affect the turbine’s performance. We carried out a series of large-eddy simulations coupled with bed morphodynamics, introducing various debris loads lodged on the upstream face of a utility-scale turbine tower. The objective is to systematically investigate the impact of debris accumulation on the performance and hydro-and morpho-dynamics interactions of the horizontal-axis MHK turbine under rigid and mobile bed conditions. To that end, we (1) employed the actuator line and surface methods for modeling turbine blades and the nacelle, respectively,(2) directly resolved individual logs, and (3) solved the Exner equation to obtain the instantaneous bed deformation of the mobile bed. Our analysis revealed that while the spinning rotor amplifies scour around the pile, debris accumulation modifies the sediment dynamics of the system. Also, it found that morphodynamic processes accelerate the wake recovery, slightly enhancing the turbine's performance.

Hossein Seyedzadeh

We present a large-eddy simulation (LES) of saliva particle transport during normal human breathing through the nose and mouth. The flow of the air–saliva mixture is modeled using an Eulerian LES that is coupled with a Lagrangian particle tracking module to obtain trajectories of saliva particles in a room with stagnant air conditions. The coupled Eulerian–Lagrangian simulation yields novel insights into the intricate dynamics of Lagrangian coherent structures (LCS) and fundamental material lines that emerge from the saliva particles' trajectories during several breathing cycles. Further, we systematically compare the quantitative LCS diagnostics of mouth breathing with those of mouth and nose normal breathing. Analyzing the simulation results of human breathing from the mouth and nose, we show that, soon after the first breathing cycle, saliva particles form a series of roll-up vortex rings that propagate forward. The forward propagation of these vortex rings leads to the formation of an asymmetrical primary forefront vortex. The individual vortex rings continuously propagate forward, merging with the forefront vortex, and ascending along the limb of the leading vortex.

Hossein Seyedzadeh

Pumping fluid is one of the crucial parts of any microfluidic system. Using electric and magnetic fields as a substitute for moving parts can have many advantages. In this study hydrodynamic and heat transfer characteristics of electroosmotic flow under influence of lateral electric and transverse magnetic field, are studied numerically. Results indicate that the dimensionless parameters such as Hartmann number, intensity of the lateral electric field, pressure gradient parameter and aspect ratio have an important role in controlling flow. It can be implied that the enhancement of pressure gradient leads to the decrease of critical Hartmann number, and this dependency can be reduced from 44% to 7% for S=0.5 to S=50 in two pressure gradients of Ω=1 and Ω=20. In addition, the reduction of aspect ratio of microchannel section leads to the increment of critical Hartmann number in a specified lateral electric field. At the end, thermal analysis is being done by consideration of the effects of magnetic and electric fields on the Nusselt number.

Hossein Seyedzadeh

The mechanical properties of different polymer matrix composites are discussed in this research study. These composites are multiphase materials in which reinforcing elements and a polymer matrix are suitably combined. The mechanical properties of 18 PMCs, including nylon 66 reinforced with 5, 15, and 25% wt% silicon carbide (SiC) and nylon 66 reinforced with 5, 15, and 25% wt% boron carbide (B4C), were evaluated using an injection moulding technique at three different injection pressures in this study. The optimization of process parameters like reinforcement material, reinforcement quantity, and injection pressure to maximize the tensile and impact strength of nylon 66 composites are the main focus of this study. It is observed that the specimens 25% SiC with an injection pressure of 90 MPa has optimised tensile strength, while the specimen 5% B4C with an injection pressure of 90 MPa has optimised impact strength.

Boopathy Govindarajan

In this research study, the mechanical properties of several Polymer matrix composites are investigated. These composites are multi-phase materials in which reinforcing materials are properly mixed with a polymer matrix. More precisely, Nylon 6 reinforced with 5, 15 and 25 wt. % of silicon carbide (SiC) and Nylon 6 reinforced with 5, 15 and 25 wt. % of boron carbide (B4C), prepared by means of an injection moulding process at three different injection pressures are considered. Specific attention is paid to the tensile and impact strength of these composites. The Taguchi technique is used to optimize the process parameters such as reinforcement material, its percentage and the injection pressure. It is observed that the specimens 5% SiC with 80 MPa injection pressure display a better tensile strength and similarly the specimen 5% B4C with 90 MPa injection pressure have a superior impact strength.

Boopathy Govindarajan

The blunted nose cone with and without a sharp aerospike and an aerodisk of various diameters and lengths are investigated numerically in detail in the current study at a hypersonic Mach number of 10. The aerodisk diameter is described as d/D ratios such as 0.2, 0.4 and 0.6, and the length of the aerospike is represented as the L/D ratio of 1, 1.5 and 2. The main objective of the research is to examine the aerodynamic properties of blunt noses with and without aerodisks and aerospikes, as well as the influence of shock production over the model. The design of blunted nose cones with aerodisk was made up using CATIA and numerical investigation was performed on the ANSYS Fluent. The turbulence model of SST k-omega was considered for study. The current study revealed that shock patterns drastically varied nearer to the nose cone model at L/D ratio 2 and variation of drag reduction occurred due to the increase in d/D ratio and aerospike and also flow pattern over the model was clearly investigated.

Boopathy Govindarajan

This research article focuses on addressing the challenges associated with joining dissimilar metals through the application of solid-state welding techniques, specifically Friction Welding (FW). The study aims to develop optimal welding conditions, tools, and parameters for achieving a successful Aluminum–Steel (Al–Fe) butt joint. The resulting weld is extensively characterized through mechanical tests, microstructure analysis, and micro hardness measurements. Additionally, finite element analysis is conducted to simulate the behaviour of the prototype engine valve. The findings provide valuable insights into the feasibility and performance of friction welding for dissimilar metal joints, contributing to the further development and understanding of this welding technique.

Boopathy Govindarajan