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

A review on industrial wastewater treatment via electrocoagulation processes

The polarization field with the function in carrier separation has aroused substantial interest. For heterojunction complexes, however, the static polarization field will be inevitably shielded by a large number of carriers. Herein, a novel hybrid consisted of single-domain PbTiO3 coated by CdS particles was selected as a model material to prove that the alternating piezoelectric field induced by periodic stress can destroy shielding effect. After the introduction of alternating piezoelectric potential by using ultrasonication, PbTiO3/CdS-10 % exhibited a much higher H2 production rate by piezo-photocatalysis (849.0 μmol h−1 g−1) than by individual piezocatalysis (400.6 μmol h−1 g−1) or photocatalysis (98.9 μmol h−1 g−1). Furthermore, the finite element simulation shows that PbTiO3/CdS heterostructure has a superior piezoelectric potential difference compare to pure PbTiO3 or pure CdS. Based on data analysis, the mechanism about the piezo-photo coupling effect was proposed, which will provide a reference for the design and development of high-efficiency piezo-photocatalyst.

Insight into the piezo-photo coupling effect of PbTiO3/CdS composites for piezo-photocatalytic hydrogen production

Nanoparticles of lead sulfide (PbS) have been grown within the pores of polyvinyl alcohol (PVA) matrix on glass substrates by chemical bath deposition at and below room temperature (30 °C). Lead acetate and thiourea, dissolved in an alkaline medium, were taken as the sources of lead and sulfur. X-ray diffraction and selected area electron diffraction studies confirmed the cubic nanocrystalline PbS phase formation. Transmission electron micrograph of the films revealed the particle size lying in the range 10–20 nm. X-ray photoelectron spectroscopic studies confirmed the presence of lead and sulfur in the films, and their atomic ratios were found to be dependent on the deposition temperature. UV–vis spectrophotometric measurement showed a direct allowed band gap lying in the range 2.40–2.81 eV, which is much higher than the bulk value (0.41 eV). The band gap decreases with the increase of deposition temperature. The dielectric constant of the PVA-capped nanocrystalline PbS was in the range 155–265 at higher frequencies, which is much higher compared to only PVA and bulk PbS.

Optical and dielectric properties of PVA capped nanocrystalline PbS thin films synthesized by chemical bath deposition

Electrochemical machining (ECM) is widely used in machining a variety of components used in aerospace, defence, automotive and medical applications. The surface roughness of the ECM process has become important because of increased quality demands. Considerable attention has been paid to achieving low surface roughness in ECM. Surface roughness is closely related to the distribution of gases and Joule heat produced during the ECM process, which affect the electrolyte electric conductivity and directly determine the surface roughness. In this report, a pulsating electrolyte, which is one of the unsteady flows that are characterized by periodic fluctuations of the mass flow rate and pressure, is first introduced to the ECM process. The ECM process is affected by the pulsating electrolyte because it can modify the heat transfer. The goal of this report is to present experimental results of the surface roughness obtained on Ti6Al4V samples using a developed pulsating electrolyte supply system in ECM. It is observed that a lower surface roughness and higher material removal rate could be obtained by using a pulsating electrolyte with proper pulsating frequency and amplitude. In direct current ECM, the surface roughness Ra is 5.7 μm, the material removal rate is 0.85 g/min at a constant electrolyte, the lowest surface roughness is 3.69 μm and the largest material removal rate is 0.92 g/min, which are obtained at a pulsating frequency of 10 Hz and amplitude of 0.2 MPa. In pulsed current ECM, the surface roughness Ra and material removal rate are 0.67 μm and 0.38 g/min at a constant electrolyte, respectively, and both the minimum surface roughness Ra of 0.53 μm and maximum material removal rate of 0.39 g/min are observed when the proper pulsating electrolyte flow frequency and amplitude are used.

Enhancement of surface roughness in electrochemical machining of Ti6Al4V by pulsating electrolyte

This paper presents a dynamic model to predict the rotor-bearing system's vibration characteristics using Dimensional Analysis (DA). A small increment in rotor unbalance, and radial clearance can cause multiple faults, ultimately causing catastrophic failure. Hence, this model considers the influence of rotor unbalance and radial clearance on the dynamics of the rotor-bearing system. Experimental investigation reveals the effects of multiple defects at different rotor speeds. Employed Response Surface Method (RSM) correlates the clearance, unbalance, and rotor speed. Comparing experimental results with the RSM and DA indicates the effectiveness of the proposed methodology for condition monitoring of high-speed machinery in process industries.

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Dynamic response analysis of unbalanced rotor-bearing system with internal radial clearance

Synthesis of fine PbE (E = S, Se) powder from direct in situ reduction of sulphur or selenium

Electrocoagulation (EC) process involves a detailed study discriminating the effect of pH, current density, the concentration of effluent and operating time. Continuous EC process was carried out with and without recirculation of DSW. Experiments were carried out to remove the color and COD of DSW by the electrocoagulation (EC). The wide range of operating conditions was implemented such as initial pH (3.1–8.7), current density (3.25–10.75A/cm2), initial COD concentration (5803 mg/L), and operating time (0–400 min). High- performance liquid chromatography (HPLC) analysis confirms the degradation of DSW. The pair of aluminum electrode removes chemical oxygen demand up to 94.88% and color 78.65%. Sludge analysis was carried out by using XRD to explore the result.

Continuous Electro Coagulation Process for the Distillery Spent Wash Using Al Electrodes

The Electrochemical Machining (ECM) is widely used in machining variety of components used in aerospace, automotive, defense, and medical applications. Due to low machining accuracy ECM is yet to be a best alternative process. ECM with pulse current offers an enhanced accuracy control. This paper presents experimental investigation of PECM parameters such as Voltage, Pulse on time and duty cycle on surface enhancement by rotating electrode (cathode tool) arrangement. This results shows PECM with rotating tool has enhanced surface by 50 % as compared to stationary tool in PECM. (1.2 to 0.7 micron). The design of experiments was done by 2 k factorial designs. The

Pradeep V. Jadhav

Papers

Dynamic response analysis of unbalanced rotor-bearing system with internal radial clearance

Synthesis of fine PbE (E = S, Se) powder from direct in situ reduction of sulphur or selenium

Continuous Electro Coagulation Process for the Distillery Spent Wash Using Al Electrodes

Enhancement of surface finish of Pulse Electrochemically Machined (PECM) surface using rotating electrode

An Experimental and Numerical Investigation on Static Vibration Response of Multi-Cracked Rotor Shaft