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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This paper details an integrated product process design model that represents process capabilities by a set of key indicators and allows for the design of products taking into account constraints set out by the process. The model is applied to Incremental sheet forming (ISF) processes and their variants. ISF processes have been developed over the past 20 years and have reached a state of development now allowing for a transition from scientific research to broader industrial application. ISF with its low part specific tooling represents a technology suitable for individualized production down to one-piece-flow. Hence, it might satisfy the growing demand for individualized products in the field of sheet metal production. However, an industrial use of ISF requires that general design rules are provided to designers to enable designs that are compatible with the capabilities of ISF. Today’s product design typically is more suitable for stamping operations than for ISF which makes the fabrication of parts by ISF difficult and increases lead time and costs. Also, different variations of ISF processes exist that are based on different machines (industrial robots, CNC machines,…) and are characterized by different capabilities, e.g. in terms of accuracy. The objective of this work is the development of an integrated product process design model and its application to ISF. The capabilities of currently available ISF processes are determined and compared to the requirements of selected products from the automotive and aero-space industry.

Design for Manufacture Based on an Integrated Product Process Design Model

Conventional strips can be converted into tailored strips by further processing such as rolling and welding. Tailored strips have a thickness or thickness distribution which is designed according to the expected loads. A new approach for the production of tailored strips is the twin roll casting of profiled strips. This technology combines the advantages of direct strip casting and the production of steel strip with an optimized cross section. In this paper the achievable process limits regarding the geometry of tailored strips with varying thickness in the cross section made by strip profile rolling, twin roll casting and welding are discussed and compared. Furthermore, experiments to demonstrate the suitability of twin roll casting to produce tailored strips made of AISI 304 stainless steel are treated. A selected tailored strip geometry of 150 x 1.5 mm2 (width x thickness) with a difference in strip thickness of 33% over the width was cast.

Tailored Strips by Welding, Strip Profile Rolling and Twin Roll Casting

The recovery behavior of a commercial aluminum alloy 3103 was investigated by the means of two alternative experimental methods: stress relaxation (SR) and double tension tests (DT). In case of SR, the stress-time evolution after deformation was recorded, and for DT the yield stress after several recovery times were measured. The DT tests were further sub-divided into tests with and without external load during recovery. The results revealed that the recovery kinetics is clearly accelerated by the external stress during the SR. However, the difference between the DT and SR stresses is much larger. It is caused by continued dislocation glide after the deformation, which causes continued plastic elongation of the specimens. This is demonstrated quantitatively by appropriate evaluation models for both experiments. In contrast to DT, the SR evaluation accounts for the elastic SR due to plastic elongation, but the recovery parameters are the same ones as for DT. This makes it possible to replace DT by SR experiments, which are materially less laborious.

Derivation of Recovery Kinetics From Stress Relaxation Tests

Experimental and numerical investigations of the plane strain compression of an oligocrystalline pure copper specimen

By using fast calculation models, the equivalent strain, temperature, and average austenitic grain size in the center of an ingot can be determined. When used in an online process monitor by coupling with a measuring system, these models are fast enough to visualize the current state of an ingot during forging. Based on a model forging process, the use of the program is demonstrated. Comparing results from metallography of the forged billet with the calculated grain size, a good agreement could be achieved (deviation of 6–24%). Even before the forging process, the presented automatic pass schedule optimization can be applied. Through this, a process could be optimized concerning a high homogeneous equivalent strain and a low number of strokes. As result of the optimization, an increasing grain size and temperature could be observed. Thus it could be useful to change other process parameters, like lowering the furnace temperature.

Gerhard Hirt

Papers

Design for Manufacture Based on an Integrated Product Process Design Model

Tailored Strips by Welding, Strip Profile Rolling and Twin Roll Casting

Derivation of Recovery Kinetics From Stress Relaxation Tests

Experimental and numerical investigations of the plane strain compression of an oligocrystalline pure copper specimen

Online Visualization during Open Die Forging and Optimization of Pass Schedules