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

Intelligent technology in grinding process driven by data: A review

Plateau honing of a diesel engine cylinder with special topography and reasonable machining time

Honing processes provide a special cross-hatch pattern to the internal surface of cylinders that favors oil flow. However, along honing operation the abrasive grains wear out and lose their ability to cut material. The honing chips mixed with oil fill the pores of the abrasives and they start cutting in an incorrect way, leading to clogging. In the present paper, honing experiments were carried out according to a 32 factorial design, with different grain size and density of abrasive grains. Roughness, material removal rate, and tool wear were determined. Acoustic emissions were also measured and the chirplet concept was applied in order to detect differences between correct and incorrect cutting operations. As a general trend roughness and material removal rate increase with grain size and with density of abrasive. However, when clogging occurs roughness and material removal rate decrease, because the abrasive grains tend to deform the material instead of cutting it. When the honing process is working appropriately, the chirplet diagram of the harmonic part of the signal shows constant marks. On the contrary, when it does not work properly, marks disappear with time and their frequencies decrease. The results of the present paper will allow monitoring the honing process in order to change the abrasives when they are not working properly.

Effect of grain size and density of abrasive on surface roughness, material removal rate and acoustic emission signal in rough honing processes

This paper deals with evaluation of the effect of grain size of abrasive particles and number of tool strokes on the roughness values (Rk, Rpk, Rvk, Mr1, Mr2, and Rp/Rt ratio) in flexible honing. The grain size factor was investigated on two levels (400 and 800 mesh) and the number of tool strokes on three levels (1, 3, and 5) based on a full factorial design 2 × 3. Flexible honing was performed after conventional honing, on 30 crankcase cylinders of hermetic compressors made in gray cast iron. The analysis of variance technique showed that the effect of abrasive grain size on the roughness was more significant than that produced by the number of tool strokes. The abrasive grain size caused statistically significant effects on Rpk, Rk, Mr2, and Rp/Rt, whereas the number of tool strokes affected Rpk only. The interaction between these factors affected Rk. The flexible honing process using 800 mesh tool grain size and five tool strokes allowed for the obtainment of surfaces similar to those that resulted from the plateau honing operation. This result can increase the field of application of this process. Flexible honing was not able to remove the waviness present on the crankcase cylinder surfaces, whose amplitude was similar to those presented by the roughness.

Effect of grain size and number of strokes on Rk parameters and emptiness coefficient in honing process

Use of results from honing test machines to determine roughness in industrial honing machines

(1) Background: Suprascapular neuropathy is an important factor contributing to shoulder pain. Given the prevalence of nerve injury and nerve block in the suprascapular notch region, as well as the frequency of arthroscopic procedures on the suprascapular notch, which are recommended in shoulder pain management, its morphology is relevant from a clinical perspective. (2) Methods: Suprascapular nerve course was studied in twelve shoulders by dissection. Its diameter was measured at omohyoid level, proximal to the suprascapular notch and distal to the spinoglenoid notch. A multi-vari chart was used in order to descriptively visualize the results. The variations found were analyzed with a mixed linear model. (3) Results: In two of the six subjects, the suprascapular nerve was divided into two motor branches proximal to the superior transverse scapular ligament. An increase in diameter around the suprascapular notch was detected, with an estimated difference between diameter means of 2.008 mm at the suprascapular notch level and 2.047 mm at the spinoglenoid notch level. (4) Conclusions: A difference in the estimated diameter detected and the fact that the motor branches, which innervate supraspinatus and infraspinatus muscle, were divided proximal to the suprascapular notch may be relevant in the diagnosis and treatment of suprascapular neuropathy and arthroscopic procedures.

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Lourdes Rodero-De-Lamo

Papers

Use of results from honing test machines to determine roughness in industrial honing machines

Variations in the Course and Diameter of the Suprascapular Nerve: Anatomical Study