Three-factor Interaction Effects Research Articles

Modeli rasta prirodnih sastojina kalabrijskog bora u središnjem mediteranskom području Turske

Stand growth models are needed for a variety of forestry practices, primarily management plans and silvicultural studies. The goal of this study was to create stand-level models for natural, pure even-aged stands of Calabrian pine in the central Mediterranean region of Turkey. The study area consists of pure and natural Calabrian pine stands located within the boundaries of the Antalya and Mersin Regional Forestry Directorates in the central Mediterranean region of Turkey. Data was collected from 486 temporary plots scattered throughout the region. Two trees (the dominant tree and the tree representing the quadratic mean diameter of the stand) were measured in each plot, yielding 972 trees. The data showed that the age varied from 6 to 135 years, the site index (SI) from 8.5 to 33.5 m, and the density from 0.3 to 12.4. The density-dependent yield tables were generated using regression equations based on stand age, SI, and stand density with individual, two-factor, and three-factor interaction effects. For SI classes I, II, and III, the optimal rotation period that would result in the highest yields for pure Calabrian pine stands is 60, 65, and 75 years, respectively. The stand growth models developed (i.e., density-dependent yield tables) agreed with the fundamental growth principles and data provided in the literature.

Adding wheat and rapeseed meal to corn-soy diets affects intestinal morphology and nutrient digestibility in broilers

This study was conducted to investigate the effects of thyme essential oil and enzyme supplementation on rations with two different energy (wheat or corn) and protein resources (soy or rapeseed meals) on gut morphology and protein digestibility of broiler chickens. Three hundred eighty-four male Ross-308 broiler chickens were used with a 23 factorial arrangement with treatments according to a completely randomized design. The morphological examinations of the intestine were carried out on 1-cm long excised segments from duodenum, jejunum and ileum. Adding wheat to the diet increased small intestine length in birds compared to other feedstuffs (P <0.05). Duodenum crypt depth and jejunum villi length were also higher in groups fed with rations containing wheat (P <0.05). Groups that received thyme essential oil and enzyme supplementation had increased length of the duodenum (P <0.05). However, the two- and three-factor interaction effects were not significant. Protein digestibility was not affected by treatment (P >0.05). Feeding wheat to broiler chickens may increase the surface area for nutrient absorption in the small intestine as compensation for the anti-nutritive activity of non-starch polysaccharides in wheat-based diets. Wheat based diets are expected to be acceptable for broilers when supplemented with appropriate enzymes or thyme essential oil.

Increasing Visitor Engagement during Interpretive Walking Tours

This study examined the effect of living-history interpretation (i.e., first-person, third-person, no living history) and question type (i.e., relevant, dissonant, customary) on engagement of visitors during walking tours at a heritage site. One hundred seventy-six visitors participated in the study. Visitors completed a measure of engagement immediately following each of six stops during the walking tour. A measure of guest familiarity of the context of the site was also taken. Results from linear mixed-modeling revealed a three-factor interaction effect, familiarity by question type by living-history interpretation. Engagement of visitors is impacted by guest familiarity with the context, the living-history interpretation type, and the question type posed. Results might guide interpretation professionals in customizing interpretation experiences to stage more engaging interpretation experiences.

Designs for Searching two Two-Factor and One Three-Factor Interaction Effect Under the Tree Structure

Abtsrcat Search designs form an indispensable tool under model uncertainty. However, the progress in this area has been limited due to com- plexities of checking the necessary rank condition for search designs. Designs for searching two two-factor and one three-factor interaction effects under a tree structure in the presence of the general mean and all the main effects are provided here. These designs are obtained under the assumption that four-factor and higher order interaction effects are all absent. Probability of correct searching obtained through simulations is also discussed.

Factorial experimental design for recovering heavy metals from sludge with ion-exchange resin

Wastewaters containing heavy metals are usually treated by chemical precipitation method in Taiwan. This method can remove heavy metals form wastewaters efficiently, but the resultant heavy metal sludge is classified as hazardous solid waste and becomes another environmental problem. If we can remove heavy metals from sludge, it becomes non-hazardous waste and the treatment cost can be greatly reduced. This study aims at using ion-exchange resin to remove heavy metals such as copper, zinc, cadmium, and chromium from sludge generated by a PCB manufacturing plant. Factorial experimental design methodology was used to study the heavy metal removal efficiency. The total metal concentrations in the sludge, resin, and solution phases were measured respectively after 30 min reaction with varying leaching agents (citric acid and nitric acid); ion-exchange resins (Amberlite IRC-718 and IR-120), and temperatures (50 and 70 °C). The experimental results and statistical analysis show that a stronger leaching acid and a higher temperature both favor lower heavy metal residues in the sludge. Two-factors and even three-factor interaction effects on the heavy metal sorption in the resin phase are not negligible. The ion-exchange resin plays an important role in the sludge extraction or metal recovery. Empirical regression models were also obtained and used to predict the heavy metal profiles with satisfactory results.

Effect of synthesis parameters in polyaniline: influence on yield and thermal behavior

Influence of chemical polymerization conditions on the yield and thermal behavior of PANI doped Dodecylbenzensulfonic (DBS) was studied by means of a 24 factorial experimental design. These conditions included temperature, concentration of dopant, concentration of oxidant and stirring rate. It was found that the thermogravimetric behavior was not sensitive to any of the conditions tested. By contrast, the yield was dependent on three of the variables studied. For 10 mmol of aniline, the maximum yield was obtained when temperature, concentration of dopant, concentration of oxidant and stirring rate were 25 °C, 27 mmol, 11.5 mmol and 500 rpm, respectively. The most important effects on the yield are the main effect of oxidant (APS), the interaction dopant concentration-stirring rate and the three-factor interaction effect of dopant concentration-oxidant concentration-stirring rate. The prediction equation is:

Optimal experimental design applied to the dehydrochlorination of poly(vinyl chloride)

Various factors are known to influence the hydrochloride release of poly(vinyl chloride) (PVC). The variables chosen for this study were heating, stirring, and illumination. For screening, the influence of these three factors on the dehydrochlorination yield of PVC swelled in sodium 3-methylbutoxide (SMB), and a sequence of experiments was planned according to a 2 3 full factorial design with two replicates. It was found that main effects, as well as two- and three-factor interaction effects, were statistically significant. Higher responses were obtained when the reaction mixture was heated under reflux in the presence of light. On the other hand, lower dehydrochlorination yields were measured when the samples were stirred.

Determination of the influence of stacking structure, float length and pressure time on the flexural properties of satin laminated composite using a factorial design

In this study, a satin weave composite was prepared by utilizing continuous fiber impregnated thermoplastic (COFIT) prepreg tapes. A 2 3 factorial design was applied to identify the main, two-factor interaction and three-factor interaction effects of stacking structure, float length and pressure time on flexural strength and modulus. It was found that, for the main effect, stacking structure exhibits great influence on the flexural strength of the satin laminated system, followed by pressure time and float length. A slight change in trend is shown by the flexural modulus, where the second important factor is float length and the third factor is pressure time. The sequence of two-factor interaction effects on the flexural strength of the satin laminated system, in ascending order, is pressure time vs. float length<float length vs. stacking structure<stacking structure vs. pressure time. The sequence of two-factor interaction effects on flexural modulus, in ascending order, is float length vs. stacking structure<float length vs. pressure time<stacking structure vs. pressure time. Finally, the results show that the three-factor interaction effect significantly influenced the flexural strength and modulus of the satin laminated system.

Resolution v.2 search designs

A fractional factorial design is called a resolution V.2 plan if it is capable of estimating all main effects and two-factor interaction effects, plus two three-factor interaction effects, In this paper, a necessary and sufficient condition for such a resolution V.2 plan is given, Furthermore, a new class of two-level resolution V.2 designs is proposed, We prove that the proposed design always satisfies such a necessary and sufficient condition, A comparison of run size between designs of resolutions VII and V.2 is made, It is shown that run size for design of resolution V.2 is significantly smaller.

Application of factorial experimental design to demonstrate the influence of processing conditions on the fusion of poly(vinyl chloride)/chlorinated polyethylene/oxidized polyethylene blends

Poly(vinyl chloride) (PVC)/chlorinated polyethylene (CPE)/oxidized polyethylene (OPE) blends were prepared in a Haake torque rheometer at various temperatures, rotor speeds, and totalized torques. A 2 3 factorial experimental design was applied to study the main two-factor interaction, and three-factor interaction effects of temperature, rotor speed, and totalized torque on the heat of fusion of PVC/CPE/OPE blends, which were examined using differential scanning calorimetry. The sequence of the main effects on the heat of fusion of PVC/CPE/OPE blends, in ascending order, is temperature < rotor speed < totalized torque. The sequence of the two-factor interaction effects on the heat of fusion of PVC/CPE/OPE blends, in ascending order, is temperature vs rotor speed < temperature vs totalized torque < rotor speed vs totalized torque. The three-factor interaction effect is not significantly related to the heat of fusion of PVC/CPE/OPE blends.

An investigation into the ball burnishing of an AISI 1045 free-form surface

This paper reports on the work undertaken in the ball burnishing of a free-form surface made from AISI 1045 medium-carbon steel. A geometric model of a free-form surface was generated using the catia solid modeler running on an IBM 5080 work-station. The NC codes generated were then down-loaded onto a 4-axis vertical machining centre for rough-milling, ball-end milling and finally ball burnishing. Preliminary experiments with 3-D curved surfaces indicated that grease is a better lubricant than machine oil in the ball-burnishing process. Using a full factorial experiment, it was found that the quality of surface finish attainable in the ball-burnishing process is affected significantly by the depth of penetration, the burnishing speed and the feed-rate. Four two-factor and four three-factor interaction effects were found to be significant at the 99% confidence level. The results of the ball-burnishing experiments on 3-D curved surfaces were analysed and a set of machining parameters selected therefrom were applied to the ball burnishing of the free-form surface. The best surface finish of the free-from surface obtained was estimated to be between 0.29 and 0.55 μm R tm.

Search designs for searching for one among the two-and three-factor interaction effects in the general symmetric and asymmetric factorials

This paper describes the construction of search designs which permit the estimation of the general mean and main-effects, and allow the search for and estimation of one possibly unknown non-zero effect among the two-and three-factor interactions in the general symmetric and asymmetric factorial set-up.

Prediction and choice in the Prisoner's Dilemma

This study utilized identical false feedback to subjects in five conditions. In two conditions the subjects played a standard two-choice prisoner's Dilemma game (200 trials); in two conditions the subjects played the standard game modified to include a prediction of Other's behavior on each trial. In each of the above situations, subjects in one condition were told that they were faced with a preset sequence while subjects in the other condition thought they were playing with one of the other subjects present in the experiment. In a fifth condition the feedback was not given any meaning as part of the game task; subjects merely had to predict the appearance of one of two lights on each of the 200 trials. The 100 subjects were assigned randomly to conditions with ten males and ten females in each condition. Analysis of the frequency of cooperative choice in the game indicates that the addition of prediction to the game had no significant main effect on choice behavior. There was a three-factor interaction effect with the description of the feedback and the trial block of the game. Subjects tended to decrease cooperation over trial blocks. The act of prediction reduced this effect for subjects who thought they faced a preset computer sequence but not for those attempting to predict the moves of a human adversary. The use of prediction data in combination with choice data produced four indices of behavior contingent upon expectation of opponent's behavior. These indices were useful in interpreting the higher cooperation of the females as an inability to find or maintain optimal strategies for maximizing their own rewards. An examination of the prediction data alone revealed that a probability matching hypothesis by itself will be inadequate to explain subjects' trial by trial expectations of Other's behavior.

&lt;i&gt;tert.&lt;/i&gt;-Butylation of Toluene: A Statistical Study

A statistical model was developed for the alkylation of toluene with tert.-butyl chloride in presence of anhydrous aluminum chloride as catalyst. Temperature, molar ratio of toluene to tert.-butyl chloride and amount of anhydrous aluminum chloride were chosen for investigation. A set of trials was planned according to a 3 factor 2-level Yates pattern experimental design with 2 replicates and the center point trial with 4 replicates. The critical response was the yield of tert.-butyl toluene. Two- and three-factor interaction effects together with the main effects were statistically significant. The adequacy of the suggested model was checked up. The difference between the experimental and predicted yields did not exceed 2.22%. The best yield of the tert.-butyl toluene was 51.2%. Key words: tert. Butylation, Yates pattern, Experimental yield, Statistical model. Â Â Â doi: 10.3329/bjsir.v43i4.2245 Bangladesh J. Sci. Ind. Res. 43(4), 545-552, 2008

A Mathematical Model for the Alkylation of &lt;i&gt;o&lt;/i&gt;-Cresol with Cyclohexanol

A mathematical model was developed for the alkylation of o-cresol with cyclohexanol in the presence of perchloric acid as a catalyst. A set of trials was planned according to a 3 factor 2-level Yates pattern experimental design. The variables chosen for the study were temperature, molar ratio of o-cresol to cyclohexanol and amount of perchloric acid. The critical response was the yield of cyclohexyl o-cresol. Main effects as well as two-and three-factor interaction effects were statistically significant. The adequacy of the suggested model was checked up. The highest experimentally found yield was 89.3% while the estimated yield was found to be 89.09%. The experimentally settings were temperature, 140O C; molar ratio of o-cresol to cyclohexanol, 6:1; amount of catalyst, 5% by wt. of o-cresol; addition time, 2 h; stirring time, 1 h. Keywords: o-Cresol, Cyclohexanol, Experimental design, Alkylation. DOI: 10.3329/bjsir.v44i2.3669 Bangladesh J. Sci. Ind. Res. 44(2), 181-186, 2009