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

Hexagonal ferrites: A review of the synthesis, properties and applications of hexaferrite ceramics

The amendment of two agricultural soils with two biochars derived from the slow pyrolysis of papermill waste was assessed in a glasshouse study. Characterisation of both biochars revealed high surface area (115 m2 g−1) and zones of calcium mineral agglomeration. The biochars differed slightly in their liming values (33% and 29%), and carbon content (50% and 52%). Molar H/C ratios of 0.3 in the biochars suggested aromatic stability. At application rates of 10 t ha−1 in a ferrosol both biochars significantly increased pH, CEC, exchangeable Ca and total C, while in a calcarosol both biochars increased C while biochar 2 also increased exchangeable K. Biochars reduced Al availability (ca. 2 cmol (+) kg−1 to <0.1 cmol (+) kg−1) in the ferrosol. The analysis of biomass production revealed a range of responses, due to both biochar characteristics and soil type. Both biochars significantly increased N uptake in wheat grown in fertiliser amended ferrosol. Concomitant increase in biomass production (250% times that of control) therefore suggested improved fertiliser use efficiency. Likewise, biochar amendment significantly increased biomass in soybean and radish in the ferrosol with fertiliser. The calcarosol amended with fertiliser and biochar however gave varied crop responses: Increased soybean biomass, but reduced wheat and radish biomass. No significant effects of biochar were shown in the absence of fertiliser for wheat and soybean, while radish biomass increased significantly. Earthworms showed preference for biochar-amended ferrosol over control soils with no significant difference recorded for the calcarosol. The results from this work demonstrate that the agronomic benefits of papermill biochars have to be verified for different soil types and crops.

Effects of biochar from slow pyrolysis of papermill waste on agronomic performance and soil fertility

Role of organic amendments on enhanced bioremediation of heavy metal(loid) contaminated soils

A review on application of flocculants in wastewater treatment

A pilot-scale reverse osmosis (RO) followed behind a membrane bioreactor (MBR) was developed for the desalination to reuse wastewater in a PVC production site. The solution-diffusion-film model (SDFM) based on the solution-diffusion model (SDM) and the film theory was proposed to describe rejections of electrolyte mixtures in the MBR effluent which consists of dominant ions (Na+ and Cl-) and several trace ions (Ca2+, Mg2+, K+ and SO42-). The universal global optimisation method was used to estimate the ion permeability coefficients (B) and mass transfer coefficients (K) in SDFM. Then, the membrane performance was evaluated based on the estimated parameters which demonstrated that the theoretical simulations were in line with the experimental results for the dominant ions. Moreover, an energy analysis model with the consideration of limitation imposed by the thermodynamic restriction was proposed to analyse the specific energy consumption of the pilot-scale RO system in various scenarios.

Model-based performance and energy analyses of reverse osmosis to reuse wastewater in a PVC production site

The aim of this paper is to study the synthesis of goethite by means of oxyprecipitation of sulphuric steel pickling liquors. The selected variables are pH, stirring velocity and flow of oxygen as oxidizer agent, a mathematical model of this synthesis being proposed from the experimental design. The model has validity in the variables' intervals. An analysis of residuals, a plot of predicted vs. observed values and an analysis of variance of the model are carried out as diagnostic probes. Posteriorly, the influence of the variables and their optimum values are determined for obtaining high quality goethite.

Mathematical model of goethite synthesis by oxyprecipitation of steel pickling liquors

Development of an integrated process (the PIBARE process) which is able to recover and recycle free and complex acids back to the pickling tank is described. The recovery of these by-products proceeds while the metals are recovered in the form of electrodeposited metal alloy and are internally recycled to the stainless steel manufacturing process. Virtually no solid residue or liquid is produced in the process. Results after three years of investigation are very promising, having achieved all stated objectives at least on the laboratory scale. The new technology promises significant economic and environmental benefits over other existing technologies for the treatment of spent baths. However, since the benefits have not been confirmed at the pilot scale, commercial application would require additional research, including finding more efficient and more selective anionic membranes. 3 tabs., 6 figs.

Novel process to recover by-products from the pickling baths of stainless steel

To reduce fresh water consumption in a polyvinyl chloride (PVC) plant, the effluent from a biological treatment must be demineralized to be re-used in the resin polymerization process Demineralization is a critical process, since the quality and the stability of the PVC resins are highly influenced by the water quality used in the process The main target values for water parameters are the following: conductivity <10 μScm−1, TOC < 10 mg L−1, and Al < 01 mg L−1 To achieve this quality, several reverse osmosis membranes from different materials and suppliers were tested and compared in the demineralization treatment Polyamide membranes showed higher salt rejection compared to cellulose acetate membranes yielding both types similar flux and permeability Two-pass reverse osmosis treatment was necessary to reach conductivities lower than 10 μS cm−1 On the other hand, a good quality effluent for reuse was obtained by combining RO and ionic exchange resins Results showed that good quality PVC resins in terms of color, granulometry, porosity, and bulk density were obtained when demineralized water from two-pass reverse osmosis was used as fresh water, proving the feasibility of the effluent reuse in the PVC industry

Assessing demineralization treatments for PVC effluent reuse in the resin polymerization step

In the time since asbestos was banned, new mixtures have been studied to obtain a product with similar properties to the asbestoscement sheets in the Hatschek process. The aim of this research is to study the effect of two different sepiolites on the physical and mechanical properties of roofing fiber-cement sheets when they contain natural fibers or mixtures of synthetic and natural fibers. Studied properties included bulk density, water absorption, permeable void volume, modulus of rupture, proportional limit, specific energy, and modulus of elasticity. The results showed that fibercement sheets containing sepiolite had better performance in terms of flexural strength and that the characteristics of the sepiolite selected played a key role in the development of the mechanical properties of the fiber-cement products.

Carlos Negro

Papers

Model-based performance and energy analyses of reverse osmosis to reuse wastewater in a PVC production site

Mathematical model of goethite synthesis by oxyprecipitation of steel pickling liquors

Novel process to recover by-products from the pickling baths of stainless steel

Assessing demineralization treatments for PVC effluent reuse in the resin polymerization step

Effect of Sepiolite on Mechanical and Physical Properties of Fiber Cement