Consistency of randomized and finite sized decision tree ensembles

Regression via classification (RvC) is a method in which a regression problem is converted into a classification problem. A discretization process is used to covert continuous target value to classes. The discretized data can be used with classifiers as a classification problem. In this paper, we use a discretization method, Extreme Randomized Discretization, in which bin boundaries are created randomly to create ensembles. We present an ensemble method for RvC problems. We show theoretically for a set of problems that if the number of bins is three, the proposed ensembles for RvC perform better than RvC with the equal-width discretization method. We use these results to show that infinite-sized ensembles, consisting of finite-sized decision trees, created by a pure randomized method (split points are created randomly), are not consistent. We also theoretically show, using a set of regression problems, that the performance of these ensembles is dependent on the size of member decision trees.     

Preparation and characterization of carboxylic cation exchange resins from the reaction of poly(vinyl alcohol) with melamine-formaldehyde and some hydroxy acids

The synthesis of cation exchange resins via the reaction of poly(vinyl alcohol) as a carrier, citric acid as a catalyst and reactive additive to produce resin structures with grafted carboxy groups, along with a melamine-formaldehyde precondensate, responsible for crosslinking-reinforcing and insolubilizing the resin structure as well as for fixing and binding the acidic functional groups onto the resin structure, has been investigated using varied molar ratios of reactants and varied time as well as temperature. Reaction conditions were selected to prepare a cation exchange resin based on citric acid. Two other cation exchange resins based on tartaric acid and glycolic acid, were also prepared under the same selected reaction conditions. These three resins were characterized by potentiometric titration, water solubility and swellability, as well as durability to use.     

Processing of an East Mediterranean phosphate ore sample by an integrated attrition scrubbing/classification scheme (part one)

ABSTRACT

In this study, an Egyptian siliceous/calcareous sedimentary phosphorite was subjected to beneficiation by unsophisticated economic means. The mineralogical and chemical examination showed that the ore sample is a typical example for the East Mediterranean phosphorites with 21.80% P₂O₅, 10.93% acid insoluble and 16.61% loss on ignition. The primary crushed sample was classified into three size fractions without any milling and they were separately subjected to an integrated attrition scrubbing study. Screening and classification on the 2.30 mm and 0.071 mm sieves were sequentially introduced with the attrition process. The effect of solid%, attrition speed and time were studied and optimized for each size fraction. Results showed that three products were produced and could be categorized according to their P₂O₅ content into the coarse tailing (+2.30 mm), the attrition concentrate (?2.30 + 0.071 mm) and the phosphate fines (?0.071 mm). The P₂O₅ contents of these products reached 12.24%, 28.72% and 18.77%, with P₂O₅ distribution reached 6.74%, 51.75% and 41.51%, respectively. A global P₂O₅ of 28.72% was obtained with a recovery of about 52%. A tentative flow-sheet for the whole process was postulated.     

Nanoscratch testing to assess the fiber adhesion of short‐carbon‐fiber composites

In a composite material, the degree of adhesion between the fiber and the matrix plays an important role in the overall performance of the material. Because the load between the fiber and the matrix is realized throughout the interphase region material, a lot of effort has gone into characterizing the strength of the interphase. In this study, nanoscratch tests on the composite samples were used to provide a relative measure of adhesion in different composite materials. Carbon‐filled nylon 6,6 and polycarbonate resins were evaluated with this method. The carbon fillers we used were polyacrylonitrile‐based carbon fibers sized and surface‐treated for the respective matrix and pitch‐based carbon fibers without any sizing or surface treatment. Tensile and X‐ray photoelectron spectroscopy data for the composites we considered are also presented to compare to the nanoscratch results. It is shown that nanoscratch testing on the composites, with the proposed data analysis, can be an effective tool for determining the relative degree of adhesion between different composites. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 328–335, 2007     

Dependence of soiling and soil release of easy care cotton on factors-controlling the finishing treatment

The conventional pad-dry-cure method was used for effecting crosslinking of cotton with N-methylol finishing agents under different conditions. Factors studied include nature and concentration of finishing agent and softener, type and concentration of catalyst, and curing temperatures. Variation of soiling and soil release characteristics of crosslinked cotton with these factors were investigated. The effect of finishing agent on aqueous soiling followed the order: Carbamate reactant-fabric > Dimethylolethylene urea-fabric > Dimethyloldihydroxyethylene urea-fabric > Untreated fabric > Modified triazinone-fabric ≥ Modified ethylene urea-fabric. On the other hand, the effect of these finishing agents was to enhance the susceptibility of the fabric to oily soiling. Nevertheless, nature of the finishing agent governed the magnitude of this enhancement. Aqueous and oily soil release depended also upon the nature of finishing agent, soiling increased and soil release decreased by increasing finishing agent concentration. Type of catalyst exerted a considerable influence on aqueous and oily soil release without significantly affecting the degree of soiling. For aqueous soil release, the following order was found: Al₂(SO₄)₃ · 18H₂O > MgCl₂ · 6H₂O > urea nitrate > ZnCl₂ · 6H₂O > Zn(NO₃)₂ · 6H₂O > urea phosphate > urea oxalate > NH₄ · H₂PO₄ ≥ NH₄Cl. A reverse order held good for oily soil release. Both aqueous and oily soil release were impaired by increasing catalyst concentration. Similarly, nature and concentration of the softener had no striking effect on soiling while they did on soil release. Raising the curing temperature from 80 to 140°C caused substantial reduction in case of soil removal of urea salts catalyzed-crosslinked cotton samples while having the degree of soiling practically intact.     

Biochemical and physiological studies of certain ticks (Ixodoidea): Isolation and partial identification of a new fatty acid in eggs ofDermacentor andersoni Stiles (Ixodidae)

Gas liquid chromatographic analysis of the fatty acid methyl esters from eggs ofDermacentor andersoni Stiles (Ixodidae) revealed the presence of significant quantities (15% total fatty acids) of an unidentified component with a retention time between C_18∶3−C_22∶0 fatty acids. Smaller amounts of the unidentified component (ca. 5% total fatty acid) also were detected in host rabbit serum. Purified, the unidentified component's methyl ester collected from the tick eggs by preparative gas liquid chromatography was partially identified and characterized by chemical and spectroscopic analyses. The evidence suggests that the unidentified component is a methyl branched C₁₅ tricarboxylic acid containing two vicinal carboxylic acid groups. Biosynthesis of the unidentified component by the tick is under investigation.     

Essential fatty acids in trout serum lipoproteins,vitellogenin and egg lipids

This paper describes evidence of (n−3) and particularly of 22∶6 (n−3) fatty acid enrichment in trout lipoproteins as well as in vitellogenin, egg lipovitellin and oil globule. Among the lipoproteins, HDL and LDL were the main forms of blood lipid transport, whereas phospholipids and cholesteryl esters are the preferential chemical carriers for (n−3) fatty acid transport. However, cholesteryl esters were less important as esterified fatty acid carriers than in man. Taken together with the data obtained in mammals, our results suggest that there may be a relationship between EFA activity and the distribution of the EFA among the lipoprotein lipid fractions in vertebrates, irrespective of the EFA series. Administration of an (n−3) fatty acid deficient diet for three months prior to trout spawning produced a significant increase in egg lipid content, primarily as a result of the increase of the oil globule composed almost exclusively of triacylglycerols. This diet decreased the 22∶6 (n−3), as well as the (n−3) fatty acid contents of lipoproteins, lipovitellin, vitellogenin and the oil globule. In contrast, the (n−3) fatty acid level was always higher in lipoproteins and lipovitellin than in the vitellogenin and the oil globule. Moreover, the relative levels of 22∶6 (n−3) and total (n−3) fatty acids were quite similar in lipoproteins and lipovitellin on the one hand, and in vitellogenin and the oil globule on the other. These findings suggest a direct relationship between the two forms of plasma lipid transport and the two egg compartments. During ovogenesis, dietary lipids seemed to be diverted from the adipose tissue and essentially deposited in the egg.     

Synthetic absorbent for dyestuffs based on gamma crosslinked poly(vinyl alcohol) (PVA)

This work reports on the characterization and uses of gamma radiation‐crosslinked poly(vinyl alcohol) (PVA) films as absorbents for different classes of dyestuffs normally released from textile factors. Dyestuffs were selected from different producers. These dyestuffs were Remacryl Blue (basic dye), Remazol Golden Orange (reactive dye), Solar Orange (direct dye), and Sandolan (acid dye). The percentage dye sorption by PVA was determined by spectroscopic analysis and color‐strength measurements of the PVA films after absorbing the different dyestuffs. The results showed that the concentration of dimethylbisacrylamide as a crosslinking agent has a great effect on the gel fraction and percentage swelling in water of the PVA polymer. In general, crosslinked PVA showed a low tendency to absorb the different dyestuffs under investigation at room temperature. This tendency was shown to increase with an increasing temperature of the dye solution from room temperature to 70°C. Meanwhile, the highest percentage of dye sorption was found in the case of the basic dye and the lowest one in the case of the reactive dye depending on the active groups on the dyes. Moreover, the percentage dye sorption by PVA was slightly higher in the acid medium rather than in the alkaline one. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 349–354, 2003     

Hydrodynamics of gas fluidized beds with mixture of group D and B particles

The dynamics of a gas‐solid fluidized bed containing Geldart Group D particles mixed with a small proportion of Geldart Group B particles are investigated using pressure fluctuations data. Time series analysis, using a variety of nonlinear dynamics tools, shows that the slugging present with Group D particles can be suppressed by the addition of a small proportion of Group B particles. The power spectra and the auto‐correlation function are used for a preliminary evaluation of dominant slug frequencies. It is shown that the bed fluidized with the mixture of Group D and B particles behaves in a less periodic manner and is dominated by more random bubble motion. On the other hand, the correlation integral is used to analyze the chaotic behaviour of the flow, through evaluation of the fractal structure of the reconstructed attractors. It is shown that the bed fluidized with Group D particles is characterized by a combination of steady slug motion and irregular particles motion. The behaviour of the fluidized bed of Group D/B particles mixture is characterized by a single correlation dimension for a wide range of fluidization velocities.