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