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

Data Mining Practical Machine Learning Tools and Techniques

This book, written by two major figures in adaptive control, provides a wealth of material for researchers, practitioners, and students. While some researchers in adaptive control may note the absence of a particular topic, the book‘s scope represents a high-gain instrument. It can be used by designers of control systems to enhance their work through the information on many new theoretical developments, and can be used by mathematical control theory specialists to adapt their research to practical needs. The book is strongly recommended to anyone interested in adaptive control.

Adaptive Control

A positive temperature coefficient is the term which has been used to indicate that an increase in solubility occurs as the temperature is raised, whereas a negative coefficient indicates a decrease in solubility with rise in temperature.

Effect of Temperature

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Almost all metal strips with thicknesses of < 2 mm are produced by cold rolling. Thickness variations of cold rolled strips are caused by various factors like fluctuation in strength of the material, the eccentricity of the rolls or thickness variation of the incoming strip. As the demands concerning the thickness variation are ever increasing the Institute of Automatic Control and the Institute of Metal Forming aim at reducing the thickness tolerance of thin, cold-rolled steel and copper strips to 1 μm. As high frequency disturbances are expected, it is assumed that this goal can only be achieved by using a predictive controller in combination with a high precision strip thickness gauge and, for roll adjustment, a piezoelectric actuator in addition to the existing electromechanical actuator. The objective of this work is the constructive implementation and the testing of a thickness gauge based on laser triangulation. The gauge includes guide rollers to prevent strip vibration, a C-frame to allow an inline calibration and mechanical adjustment of the measuring range so that even flexible strip thicknesses can be measured. The designed gauge showed a high repeat accuracy of 0.4 μm for two different metal strips. Furthermore the gauge was used to investigate the dynamics of the thickness change of a steel strip at maximum rolling speed of 5 m/s using a Fourier transformation. This frequency analysis supports the need for a piezoelectric actuator that can also subsequently be dimensioned based on the obtained frequency data.

Development of a Laser Triangulation Gauge for High Precision Strip Thickness Control

To provide a high quality of forged products, a homogeneous distribution of material properties has to be achieved inside the ingot. As the properties are not visible from the outside, an online monitoring during the forging process is required. By using modern measuring equipment and fast calculation models, the equivalent strain, temperature and average grain size in the core fibre of a forging ingot can be calculated parallel to the process. Software implementing the fast calculation models has been established and connected to the measuring system of two different open die forging presses. Two experimental forging processes with ten passes have been performed (20 ton steel ingot, 750 kg Ni-base alloy ingot). Parallel to the process, the current strain, temperature and average grain size in the centre of the ingot are visualised in the graphic user interface and recorded by the process monitor. It was shown that the calculation speed is high enough to allow online capability. After finishing the process, the developed software can further be used to analyse in detail the impact of every single stroke or pass on the whole process. Additionally, information like minimum or maximum grain size or recrystallized fraction is calculated and can be used to get insight into the process and optimize its design. Comparing the metallographically measured average grain size from experiment with the grain size estimated by the process monitor, the average deviation of three measured points is less than 13 %.

Application of a Fast Calculation Model for the Process Monitoring of Open Die Forging Processes

A current driving force of research is lightweight design. One of the approaches to reduce the weight of a component without causing an overall stiffness decrease is the use of multi-material components. One of the main challenges of this approach is the low bonding strength between different materials. Focusing on steel-aluminum multi-material components, thermally sprayed copper coatings can come into use as a bonding agent between steel sheets and high pressure die cast aluminum to improve the bonding strength. This paper presents a combination of cold gas spraying of copper coatings and their subsequent structuring by rolling as surface pretreatment method of the steel inserts. Therefore, flat rolling experiments are performed with samples in "as sprayed" and heat treated conditions to determine the influence of the rolling process on the bond strength and the formability of the coating. Furthermore, the influence of the rolling on the roughness and the hardness of the coating was examined. In the next step, the coated surface was structured, to create a surface topology suited for a form closure connection in a subsequent high-pressure die casting process. No cracks were observed after the cold rolling process with a thickness reduction of up to e = 14 % for heat treated samples. Structuring of heat treated samples could be realized without delamination and cracking.

https://iopscience.iop.org/article/10.1088/1757-899X/181/1/012028/pdf

Investigation on the cold rolling and structuring of cold sprayed copper-coated steel sheets

The magnetic properties of non-oriented electrical steel, widely used in electric machines, are closely related to the grain size and texture of the material. How to control the evolution of grain size and texture through processing in order to improve the magnetic properties is the research focus of this article. Therefore, the complete process chain of a non-oriented electrical steel with 3.2 wt.-% Si was studied with regard to hot rolling, cold rolling, and final annealing on laboratory scale. Through a comprehensive analysis of the process chain, the influence of important process parameters on the grain size and texture evolution as well as the magnetic properties was determined. It was found that furnace cooling after the last hot rolling pass led to a fully recrystallized grain structure with the favorable ND-rotated-cube component, and a large portion of this component was retained in the thin strip after cold rolling, resulting in a texture with a low γ-fiber and a high ND-cube component after final annealing at moderate to high temperatures. These promising results on a laboratory scale can be regarded as an effective way to control the processing on an industrial scale, to finally tailor the magnetic properties of non-oriented electrical steel according to their final application.

Influence of Process Parameters on Grain Size and Texture Evolution of Fe-3.2 wt.-% Si Non-Oriented Electrical Steels.

Rotary peen forming (RPF) is a new peen forming process in which the shot rotates on a circular path. Compared to traditional shot peen forming (SPF) processes, RPF does not need refeed of shot particles Hence, RPF promises a compact machine design and a flexible use if the RPF unit is operated manually (at low rotation speeds) or by a robot or CNC machine. The RPF process causes localised plastic deformation just as in traditional shot peen forming but involves tangential contact forces which create shear deformation in the plastic layer. This results in different process mechanics than in traditional shot peen forming processes. In this paper, two set-ups for RPF developed at the University of Cambridge and the RWTH Aachen are presented. First experimental results are given showing that RPF is capable of forming aluminium and steel sheets in various thicknesses. The dynamic effects that occur due to the impact at high rotations speeds are analysed using high speed video processing. Finally, the process mechanics of RPF are analysed using finite element simulations and compared to traditional shot peen forming. © 2011 IBF (RWTH Aachen) & IUL (TU Dortmund).

Gerhard Hirt

Papers

Development of a Laser Triangulation Gauge for High Precision Strip Thickness Control

Application of a Fast Calculation Model for the Process Monitoring of Open Die Forging Processes

Investigation on the cold rolling and structuring of cold sprayed copper-coated steel sheets

Influence of Process Parameters on Grain Size and Texture Evolution of Fe-3.2 wt.-% Si Non-Oriented Electrical Steels.

The development of a new peen forming process - Rotary peen forming