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

1: Magnetic Particles: Preparation, Properties and Applications: M. Ozaki. 2: Maghemite (gamma-Fe2O3): A Versatile Magnetic Colloidal Material C.J. Serna, M.P. Morales. 3: Dynamics of Adsorption and Oxidation of Organic Molecules on Illuminated Titanium Dioxide Particles Immersed in Water M.A. Blesa, R.J. Candal, S.A. Bilmes. 4: Colloidal Aggregation in Two-Dimensions A. Moncho-Jorda, F. Martinez-Lopez, M.A. Cabrerizo-Vilchez, R. Hidalgo Alvarez, M. Quesada-PMerez. 5: Kinetics of Particle and Protein Adsorption Z. Adamczyk.

Surface and Colloid Science

https://www.pure.ed.ac.uk/ws/files/79828523/79828403._Masek._AAM.pdf

A critical review of clay-based composites with enhanced adsorption performance for metal and organic pollutants.

Stop or Go on Oxide Surfaces Direct studies of surface diffusion with instruments such as the scanning tunneling microscope (STM) have often focused on species on metal surfaces, but surface diffusion can play an important role for reactions on metal oxide surfaces. Li et al. (p. 882) used STM and density functional theory calculations to study how catechol (a benzene ring bearing two −OH groups) diffuses on the surface of the rutile phase of titanium dioxide. Both mobile and immobile species were observed on the time scale of minutes while making repeated STM scans. Hydrogen atom transfers between surface OH groups and the molecule changed the interaction energy between the molecule and the surface, and hence the barrier for diffusion. The diffusion barrier for an organic molecule on a hydroxylated metal oxide surface depends on hydrogen bond formation. Direct studies of how organic molecules diffuse on metal oxide surfaces can provide insights into catalysis and molecular assembly processes. We studied individual catechol molecules, C6H4(OH)2, on a rutile TiO2(110) surface with scanning tunneling microscopy. Surface hydroxyls enhanced the diffusivity of adsorbed catecholates. The capture and release of a proton caused individual molecules to switch between mobile and immobile states within a measurement period of minutes. Density functional theory calculations showed that the transfer of hydrogen from surface hydroxyls to the molecule and its interaction with surface hydroxyls substantially lowered the activation barrier for rotational motion across the surface. Hydrogen bonding can play an essential role in the initial stages of the dynamics of molecular assembly.

http://absimage.aps.org/image/MAR11/MWS_MAR11-2010-004354.pdf

Hydrogen Bonding Controls the Dynamics of Catechol Adsorbed on a TiO$_{2}$(110) Surface

The efficient separation of scheelite from calcium-bearing minerals, especially calcite, remains a challenge in practice. In this work, a novel reagent scheme incorporating a depressant of sodium hexametaphosphate (SHMP) and a collector mixture of octyl hydroxamic acid (HXMA-8) and sodium oleate (NaOl) was employed in both single and mixed binary mineral flotation, and it proved to be highly effective for the separation. Furthermore, the role of the pH value in the separation was evaluated. Additionally, the mechanism of the selective separation was investigated systemically via zeta potential measurements, fourier transform infrared (FTIR) spectroscopy analysis, X-ray photoelectron (XPS) spectroscopy analysis and crystal chemistry calculations. It turns out that the selective chemisorption of SHMP on calcite (in the form of complexation between H2PO4−/HPO42− and Ca2+) over scheelite is ascribed to the stronger reactivity and higher density of Ca ions on the commonly exposed surfaces of calcite minerals. The intense adsorption of HXMA-8 on scheelite over calcite due to the match of the O O distances in WO42− of scheelite and CONHOH of HXMA-8 holds the key to the successful separation. We were also interested in warranting the previous claim that NaOl is readily adsorbed on both minerals via chemisorption. Our results provided valuable insights into the application of mixed collectors and an effective depressant for flotation separation.

Zhiyong Gao

Papers

Adsorption of a novel reagent scheme on scheelite and calcite causing an effective flotation separation.

Selective flotation of scheelite from calcite and fluorite using a collector mixture

Fatty acid flotation versus BHA flotation of tungsten minerals and their performance in flotation practice

Anisotropic surface energies and adsorption behaviors of scheelite crystal

Adsorption mechanism of new mixed anionic/cationic collectors in a spodumene-feldspar flotation system