A Note on Estimation of Population Mean in Sample Survey using Auxiliary Information

In this paper we have suggested a class of estimators for population mean using auxiliary information in two-phase sampling. When the population mean  is not known, a class of estimators for finite population mean  of the study variable y has been suggested. Expressions of bias and mean squared error are obtained upto the first order of approximation. Asymptotically optimum estimators (AOE’s) are also identified with its mean squared error formula. We found that proposed class of estimator are better than usual ratio and other estimators

Application of Taguchi Method in Optimization of Tool Flank Wear Width in Turning Operation of AISI 1045 Steel

In this paper, Taguchi techniques are applied to find out the optimum tool flank wear width in turning operation of AISI 1045 Steel. A L9 orthogonal array, S/N ratios and ANOVA are used to study the performance characteristics of cutting speed, feed rate and depth of cut as turning parameters with tool flank wear width as response variable. The result of the analysis show that the selected machining parameters affect significantly the tool flank wear width of Tungsten Carbide cutting tool while machining AISI 1045 steel and also indicate that the cutting speed is the most influencing parameter out of the three parameters under study. Finally, the results are further confirmed by validation experiments or confirmation run. Keywords: Taguchi Method, Optimization, Tool flank wear width, S/N ratio, ANOVA

Numerical Simulation and Assessment of Meta Heuristic Optimization Based Multi Objective Dynamic Job Shop Scheduling System

In today's world of manufacturing, cost reduction becomes one of the most important issues. A successful business needs to reduce its cost to be competitive. The programming of the machine is playing an important role in production planning and control as a tool to help manufacturers reduce their costs maximizing   the   use   of   their   resources.   The   programming problem is not only limited to the programming of the machine, but also covers many other areas such such as computer and information technology and communication. From the definition, programming is an art that involves allocating, planning the allocation and utilization of resources to achieve a goal. The aim of the program is complete tasks in a reasonable amount of time. This reasonableness is a performance measure of how well the resources   are   allocated   to   tasks.   Time   or   time-dependent functions are always it used as performance measures. The objectives of this research are to develop Intelligent Search Heuristic algorithms (ISHA) for equal and variable size sub lot for  m  machine  flow  shop  problems,  to  Implement  Particle Swarm Optimization algorithm (PSO) in matlab, to develop PSO based Optimization program for efficient job shop scheduling problem. The work also address solution to observe and verify results of PSO based Job Shop Scheduling with help of graft chart

Multi-Objective Optimization In Turning Of Cylindrical Bars Of AISI 1045 Steel Through Taguchi

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Synthesis of Patterned Vertically Aligned Carbon Nanotubes by PECVD Using Different Growth Techniques : A Review

Immense development has been taken place not only to increase the bulk production, repeatability and yield of carbon nanotubes (CNTs) in last 25 years but preference is also given to acknow ledge the basic concepts of nucleation and growth methods. Vertically aligned carbon nanotubes (VACNTs) are forest of CNTs accommodated perpendicular on a substrate. Their exceptional chemical and physical properties along with sequential arrangement and d ense structure make them suitable in various fields. The effect of different type of selected substrate, ca rbon precursor, catalyst and their physical and chemical st atus, reaction conditions and many other key parameters have been thoroughly studied and analysed . The aim of this paper is to specify the trend and summarize the effect of key parameters instead of only presenting all the experiments reported till date. The identified trends will be compared with the recent observations on the growth of diffe rent types of patterned VACNTs

INVESTIGATION THOUGHT DECISION-MAKING TRIAL AND EVALUATION LABORATORY (DEMATEL) IN GREEN SUPPLY CHAIN MANAGEMENT INCLUDE REDUCING AND RECYCLING PHARMACEUTICAL WASTE FOR A PHARMACEUTICAL MANUFACTURER IN INDIA IJIERD © I A E M E

ABSTRACT This study presented an integrated approach for selecting appropriate suppliers in addressing Pharmaceutical Green Supply Chain Management (PGSCM) of environment change via Multiple Criteria Decision Making Method (MCDM). In this study, thirteen criteria of Pharmaceutical Green Supply Chain Management with three dimensions were identified from literature review and interview with three experts in a Pharmaceutical manufacturer. By considering the interrelationships among criteria, the Decision-Making Trial and Evaluation Laboratory (DEMATEL) were applied to deal with the importance and causal relationships among the evaluation criteria of supplier selection. As indicated by the results, the four most important criteria are internal environmental management, involvement in initiatives for negative economic, training related reducing waste management, and green purchasing. The results also found that the top four criteria not only have potential significance in the selection of green suppliers with waste management competencies, but also affect the other twelve criteria, separately

Optimal laptop VDU parameter setting using Taguchi method

This paper shows that the Taguchi method of optimization can be easily used in optimizing the visual display unit (VDU) parameters for maximizing the readability on the laptop. Researchers use five factors, each at three levels which are font size, font style, line spacing, viewing distance and screen inclination angle with reading time in seconds (for reading about 300 words) as the response variable. Other parameters like text/background color combination (black/white), table height, illumination etc. were kept constant. Experiments were conducted by varying different parameters on the basis of L27 orthogonal array design. Results show that there is a 15.3% decrease in mean reading time when working at optimal condition. Results also show that factor A is the most important factor which is font size followed by factor C (line spacing), factor E (screen inclination angle), factor D (viewing distance) and factor B (the font style) which is the least important factor

Elastic and fracture characteristics of graphene-silicon nanosheet composites using nonlinear finite element method

A simple and efficient methodology is proposed for computing the nonlinear stress-strain behavior and fracture strength under tensile loading of graphene-silicon nanosheet composites. A nonlinear finite-element model (FEM) is developed to obtain the stress-strain relationships, which in general are computed using the computationally expensive procedure of molecular dynamics (MD) simulations. The modelling method, based on the interconnection of continuum micro-mechanics approaches, incorporates bonded contact at the graphene-silicon interface with the graphene being modelled as the multilinear elastic and the silicon assumed as an isotropic material is fed into an atomistic progressive fracture model. Using this model, we get the nonlinear behaviour of graphene, silicon and its composites, as a nonlinear stress-strain curve with their critical stress at inflection point leading to failure. The obtained results of the stress-strain curves, the elastic modulus and the critical stresses of single layer graphene (SLG), silicon nanosheet and their composites (GSNC) with different thickness of silicon nanosheet are in good agreement with the MD results available in the literature. These results elucidate that the tensile strength and Young's modulus of the silicon nanosheet increase enormously by putting the graphene layer on the top and bottom surface of the silicon nanosheet. This model is then employed to study the non-linear stress behaviour for the different orientations of silicon with varying thickness and their corresponding composites with graphene and the effect of various chirality of SLGs are also considered. Thus, we try to establish FEM as a reliable numerical method to obtain the mechanical behaviour of graphene-silicon nanosheet composites which for long-time has been solved using the classical approach of MD. The parametric study which is done using the developed FEM model shows that the GSNC helps to enhance the mechanical properties of silicon nanosheet, which in turn is helpful for the silicon-based semiconductor industry. This fact correlates well with the other methods, well-established in the literature

Static and Dynamic Characteristics of Nano and Microstructures

With the improvement in micro and nanofabrication processes, researchers are able to control the growth and fabrication of single or arrays of nanotubes or nanofibres. While single walled carbon nanotube (SWCNT) and double-walled carbon nanotube (DWCNT) are used for designing resonators, others used them in the form of arrays such as vertically aligned carbon nanotubes (VACNTs) to increase the surface area for other applications. When nanotubes are used as a vertically aligned form, the bulk properties change with respect to single SWCNT or DWCNT as these tubes are bonded together with interatomic non-bonded potential such as the van der Waals interactions. Moreover, under a given compressive loads, VACNTs buckle under different buckling load. Therefore, it is imperative to understand the variation of elastic and buckling properties of VACNTs with number of tubes under the presence of van der Waals potential between the neighbouring tubes. Since, the properties of SWCNTs and MWCNTs also depend on their configuration, the effect of configuration on elastic and buckling properties are also analyzed. In order to use excellent properties of carbon to improve the properties of other planer structures such as microelectromechanical system (MEMS) or nanoelectromechanical system (NEMS), many graphene-based MEMS/NEMS devices are explored. Thus, fracture properties and elastic properties of graphene silicon composites need to be investigated under the different configuration of graphene and different crystallographic conditions of silicon. Additionally, we also investigate the size effect on elastic properties of graphene-silicon nanocomposites. After finding mechanical properties under static condition, we also perform the vibrational analysis of graphene-silicon and horizontally aligned carbon nanotube-silicon composites with and without surface effects. Finally, we investigate the performance of nanofibers mat in tuning the frequency of hexagonal and rectangular shape microcantilever beams based on experimental and numerical results. The methodology developed in the thesis can be effectively used to model different types of carbon-based flexible substrate for the development of large area based sensors and actuators in the future