THE DESIGN AND ANALYSIS OF EXPERIMENTS. By Oscar Kempthorne. New York, John Wiley and Sons, Inc., 1952. 631 pp. $8.50. This book by a teacher of statistics (as well as a consultant for \"experimenters\") is a comprehensive study of the philosophical background for the statistical design of experiment. It is necessary to have some facility with algebraic notation and manipulation to be able to use the volume intelligently. The problems are presented from the theoretical point of view, without such practical examples as would be helpful for those not acquainted with mathematics. The mathematical justification for the techniques is given. As a somewhat advanced treatment of the design and analysis of experiments, this volume will be interesting and helpful for many who approach statistics theoretically as well as practically. With emphasis on the \"why,\" and with description given broadly, the author relates the subject matter to the general theory of statistics and to the general problem of experimental inference. MARGARET J. ROBERTSON

The Design and Analysis of Experiments

http://doras.dcu.ie/17608/1/Final_Version%2C_Review_paper.pdf

Optimization of different welding processes using statistical and numerical approaches - A reference guide

Increasing energy demand and environment concerns have prompted an evolution of alternative fuel sources. As an alternative fuel source, biodiesel is attractive because it reduces engine emissions. However, biodiesel produces higher NOx emissions compared to ordinary diesel fuel. Previous researches have established many factors that cause biodiesel to produce elevated NOx emissions. This study reviews the impacts of biodiesel combustion on NOx emissions and their reduction approaches in diesel engines. The first part of this study recaps the NOx formation mechanisms for understanding the kinetics behind the NOx forming reactions. The second part describes the factors affecting on NOx emissions. This paper established that higher NOx emissions are produced for biodiesel combustion which influenced by several factors such as physicochemical properties and molecular structure of biodiesel, adiabatic flame temperature, ignition delay time, injection timing and engine load conditions etc. The final section discusses on the reduction of NOx emissions from biodiesel fuelled engines for both pre and post combustion techniques. The results of reduction approaches of the NOx emissions implies, exhaust gas recirculation (EGR) and retarded injection timing are effective as well as low cost techniques than others. Between these two techniques, EGR reduces the NOx emissions at 5–25% EGR rate adequately in biofuelled engine by controlling oxygen content and combustion peak temperature with slightly decreasing HC and CO emissions. However this technique shows few penalties on smoke and PM emissions as well as brake specific fuel consumption if not perfectly optimized.

Impacts of biodiesel combustion on NOx emissions and their reduction approaches

Effect of welding processes and conditions on the microstructure, mechanical properties and corrosion resistance of duplex stainless steel weldments—A review

The single weld bead geometry has critical effects on the layer thickness, surface quality, and dimensional accuracy of metallic parts in layered deposition process. The present study highlights application of a neural network and a second-order regression analysis for predicting bead geometry in robotic gas metal arc welding for rapid manufacturing. A series of experiments were carried out by applying a central composite rotatable design. The results demonstrate that not only the proposed models can predict the bead width and height with reasonable accuracy, but also the neural network model has a better performance than the second-order regression model due to its great capacity of approximating any nonlinear processes. The neural network model can efficiently be used to predict the desired bead geometry with high precision for the adaptive slicing principle in layer additive manufacturing.

Bead geometry prediction for robotic GMAW-based rapid manufacturing through a neural network and a second-order regression analysis

Effect of flux cored arc welding process parameters on duplex stainless steel clad quality

Weld cladding is a process of depositing a thick layer of a corrosion resistance material over carbon steel plate to improve the corrosion resistance properties. The main problem faced in stainless steel cladding is the selection of process parameters for achieving the required clad bead geometry and its shape relationships. This paper highlights an experimental study carried out to develop mathematical models to predict clad bead geometry and its shape relationships of austenitic stainless steel claddings deposited by gas metal arc welding process. The experiments were conducted based on four-factor, five-level central composite rotatable design with full replication technique. The mathematical models were developed using multiple regression method. The developed models have been checked for their adequacy and significance. The direct and interaction effects of process parameters on clad bead geometry and its shape relationships are presented in graphical form.

Effect of process parameters on clad bead geometry and its shape relationships of stainless steel claddings deposited by GMAW

Comparative study of performance and emission characteristics of a diesel engine fueled by emulsified biodiesel/diethyl ether blended biodiesel.

Effect of flux cored arc welding process parameters on bead geometry in super duplex stainless steel claddings

The effect of flux-cored arc welding (FCAW) process parameters on the quality of the super duplex stainless steel (SDSS) claddings can be studied using Taguchi L9 design of experiments. In this experimental investigation, deposits were made with 30 % bead overlap. Establishing the optimum combination of process parameters is required to ensure better bead geometry and desired properties. The above objectives can be achieved by identifying the significant input process parameters as input to the mathematical models like welding voltage (X
 1), wire feed rate (X
 2), welding speed (X
 3), and nozzle-to-plate distance (X
 4). The identified responses governing the bead geometry are bead width (W) and height of the reinforcement (H). The mathematical models were constructed using the data collected from the experiments based on Taguchi L9 orthogonal array. Then, the responses were optimized using non-traditional nature-inspired technique like genetic algorithm (GA).

T. Kannan

Papers

Effect of flux cored arc welding process parameters on duplex stainless steel clad quality

Effect of process parameters on clad bead geometry and its shape relationships of stainless steel claddings deposited by GMAW

Comparative study of performance and emission characteristics of a diesel engine fueled by emulsified biodiesel/diethyl ether blended biodiesel.

Effect of flux cored arc welding process parameters on bead geometry in super duplex stainless steel claddings

Optimization of flux-cored arc welding process parameters by using genetic algorithm