Effects of moisture, location, and angle on automotive paint system appearance during natural weathering.This article presents results from a simple Design of Experiment (DOE) in natural outdoor weathering. Results show comparative effects of three weathering variables: moisture, exposure angle, and exposure location. The experiment design reveals rank importance of the study variables and links characteristics of the outdoor weathering environment with appearance degradation DEGRADATION, punishment, ecclesiastical law. A censure by which a clergy man is deprived of his holy orders, which he had as a priest or deacon. of coatings. The DOE data follows gloss retention of four automotive paint systems over 96 months in subtropical sub·trop·i·cal adj. Of, relating to, or being the geographic areas adjacent to the Tropics. subtropical Adjective of the region lying between the tropics and temperate lands Florida and desert Arizona. The article discusses some of the root causes and co-variables which may explain automotive paint appearance degradation. INTRODUCTION AND BACKGROUND The Moisture Variable Researchers know moisture plays a key role in weathering of many materials and often place moisture in a set of three primary weathering variables with sunlight and temperature. Researchers use southern Florida as a weathering reference environment because of its relative humidity relative humidity n. The ratio of the amount of water vapor in the air at a specific temperature to the maximum amount that the air could hold at that temperature, expressed as a percentage. , rain, condensation, and the important effect moisture plays in weathering. Researchers also make great efforts to include moisture variable control in artificial weathering tests for both simulation and acceleration of natural outdoor weathering degradation. (1) Moisture represents an important focus for weathering studies, exposure standards, service life prediction methodology, and weathering device design. (2-5) Several recent studies also show the important effect of moisture on material degradation rates and characteristics of automotive coating systems. (6,7) Because of these historic and recent perspectives of moisture's role in degradation of automotive coatings, a research goal was identified to perform a simple weathering experiment designed to help quantify Quantify - A performance analysis tool from Pure Software. the role of the moisture variable compared to other weathering variables on auto coating degradation. One study objective included using natural outdoor weathering rather than artificial or accelerated methods. Another study objective included tracking long-term degradation (longer than five years outdoor weathering) in order to characterize the naturally occurring long-term appearance degradation pattern, rather than only the initiation portion of the degradation function. In 1998, researchers planned a simple DOE to meet these objectives and began exposure and measurement of commercially available automotive paint systems. This simple study illustrates the important and powerful role moisture can have on weathering degradation rates and underlines the care and consideration researchers need to use to incorporate the moisture variable into experiments and tests aimed at predicting material end-use outdoor performance. [ILLUSTRATION OMITTED] The DOE Approach to Weathering Experiments Traditional natural outdoor weathering studies ordinarily or·di·nar·i·ly adv. 1. As a general rule; usually: ordinarily home by six. 2. In the commonplace or usual manner: ordinarily dressed pedestrians on the street. consist of simple exposures of material specimens in outdoor environments for periods of time while making intermittent intermittent /in·ter·mit·tent/ (-mit´ent) marked by alternating periods of activity and inactivity. in·ter·mit·tent adj. 1. Stopping and starting at intervals. 2. measurements of material characteristics throughout the exposures. Sometimes the measured characteristic (also known as "output variable" or "dependent variable") is graphed on a y-axis with some appropriate measurement of exposure duration on the x-axis to form a curve or degradation function. These exposure trials are typically observational in nature as researchers do not try to influence the naturally occurring environmental variables (also known as "input variables" or "independent variables") causing the degradation. Sometimes researchers construct actual experiments using these outdoor exposure trials. An example may be when a researcher considers different additives or amounts of a single additive additive In foods, any of various chemical substances added to produce desirable effects. Additives include such substances as artificial or natural colourings and flavourings; stabilizers, emulsifiers, and thickeners; preservatives and humectants (moisture-retainers); and in a system to promote outdoor weathering durability. The researcher sets up an experiment subjecting specimens with varying types or amounts of additives to an outdoor weathering exposure trial. Degradation curves can then be analyzed an·a·lyze tr.v. an·a·lyzed, an·a·lyz·ing, an·a·lyz·es 1. To examine methodically by separating into parts and studying their interrelations. 2. Chemistry To make a chemical analysis of. 3. to assess the best additive or best amount. In this style of experiment, however, the researcher is controlling the material variable. The additive type or amount represents the independent variable controlled by the researcher. The researcher usually does not control environmental variables as a part of this type of weathering experiment and, consequently, gathers no information on how changing environmental factors affect the degradation characteristics. More recently, weathering researchers have begun considering effects of environmental variables on degradation characteristics by performing experiments on standard specimens while varying environmental factors in artificial weathering devices to determine how different levels of an environmental factor (the independent variable in this case) affects a degradation function. For example, an experiment may expose standard specimens to different relative humidity levels while holding other variables constant (such as spectral power distribution In color science, the power per unit area per unit wavelength of a radiant object. Mathematically, one may write: where , irradiance ir·ra·di·ant adj. Sending forth radiant light. [Latin irradi level, temperature, etc.). Typically, these experiments vary only one environmental factor at a time under artificially controlled conditions. This approach is sometimes known as an "OFAT" (one-factor-at-a-time) experiment. The OFAT approach to natural outdoor weathering research is extremely difficult to perform correctly. It is realistically impossible to only vary one environmental factor at a time in a natural outdoor exposure. Therefore, OFAT experiments typically utilize artificial weathering devices to only vary a single independent weathering variable while holding other factors constant. Natural outdoor environments, however, never generate single factor variation while other factors remain constant! The phrase "n-dimensional hypervolume" underscores the dynamic multi-variable outdoor environment's interaction with materials. (8) Likewise, for this reason, single OFAT weathering experiments can be considered highly artificial and over-simplistic constructs offering only meager mea·ger also mea·gre adj. 1. Deficient in quantity, fullness, or extent; scanty. 2. Deficient in richness, fertility, or vigor; feeble: the meager soil of an eroded plain. 3. information relating back to material performance in the natural outdoor weathering environment hypervolume. OFAT experiments simply do not have the power to characterize weathering processes occurring in the n-dimensional hypervolume of the natural weathering environment. DOE approaches, however, do. "Design of Experiments [DOE] is the simultaneous study of several process variables. By combining several variables in one study instead of creating a separate study for each, the amount of testing required will be drastically dras·tic adj. 1. Severe or radical in nature; extreme: the drastic measure of amputating the entire leg; drastic social change brought about by the French Revolution. 2. reduced and greater process understanding will result. This is in direct contrast to the typical one-factor-at-a-time approach or OFAT which limits the understanding and wastes data. Additionally, OFAT studies cannot be assured of detecting the unique effects of combinations of factors (a condition to be later defined as an interaction)." (9) A weathering DOE, therefore, is simply a traditional DOE which varies several weathering factors (variables) simultaneously to characterize the effects of individual factors and their interactions on the study material. DOEs include two types: fractional fractional size expressed as a relative part of a unit. fractional catabolic rate the percentage of an available pool of body component, e.g. protein, iron, which is replaced, transferred or lost per unit of time. factorial factorial For any whole number, the product of all the counting numbers up to and including itself. It is indicated with an exclamation point: 4! (read “four factorial”) is 1 × 2 × 3 × 4 = 24. (sometimes called screening experiments) and full factorial DOEs. Researchers typically use fractional factorial experiments fac·to·ri·al experiment n. An experimental design in which two or more series of treatments are tried in all combinations. factorial experiment see factorial experiment. to narrow a collection of many suspect variables down to a few significant variables and identify the variables that warrant further investigation while screening out variables that do not. Once identified in screening approaches, full factorial DOEs then can be performed for robust characterization A rather long and fancy word for analyzing a system or process and measuring its "characteristics." For example, a Web characterization would yield the number of current sites on the Web, types of sites, annual growth, etc. of the main effects and interactions of the few key variables. For this study, the screening experiments were presented in separate publications. (10,11) [FIGURE 1 OMITTED] Design and implementation of DOEs using natural weathering factors may present considerable difficulties in natural environments. The power and efficiency of weathering DOE approaches, however, often outweigh out·weigh tr.v. out·weighed, out·weigh·ing, out·weighs 1. To weigh more than. 2. To be more significant than; exceed in value or importance: The benefits outweigh the risks. these difficulties and justify using weathering DOE approaches. DESIGN OF EXPERIMENT Researchers planned a simple natural weathering DOE to help understand the effects of moisture on gloss degradation of automotive coatings. The study objectives included obtaining information which compared the effects of moisture to two other weathering factors: exposure location and exposure angle. These three variables--moisture, exposure location, and exposure angle--naturally fit into a [2.sup.3] full factorial DOE. Figure 1 shows this weathering DOE modified from Montgomery. (12) Weathering DOE Trials This DOE included eight long-term weathering exposures varying the three factors (moisture, exposure angle, and location) simultaneously. The experiment design varied the three factors in an orthogonally or·thog·o·nal adj. 1. Relating to or composed of right angles. 2. Mathematics a. Of or relating to a matrix whose transpose equals its inverse. b. balanced manner. Contrasting trials varied each factor to a low (-) and high (+) setting independently of the other factor settings. All eight exposures began within three days of November 20, 1998, and continued throughout the 96 months reported here within. Every three months, the exposed automotive coating specimens were measured and the measurements were plotted against exposure time in order to obtain the degradation curves for each of the eight exposures. In this manner, the DOE characterized char·ac·ter·ize tr.v. character·ized, character·iz·ing, character·iz·es 1. To describe the qualities or peculiarities of: characterized the warden as ruthless. 2. the long-term weathering degradation for each variable setting. All specimens were exposed in the backed condition. Exposure and Independent Variables Varying independent environmental factors in a natural outdoor weathering experiment may seem paradoxical paradoxical different from what is expected; at variance with the established laws. paradoxical motion see paradoxical respiration (below). . "Controlling" a natural environment makes it un-natural. For example, it would be difficult to perform a DOE that actually controlled the temperature of exposed specimens using heating elements Noun 1. heating element - the component of a heater or range that transforms fuel or electricity into heat bar - a heating element in an electric fire; "an electric fire with three bars" while still maintaining the natural cyclic cyclic /cyc·lic/ (sik´lik) pertaining to or occurring in a cycle or cycles; applied to chemical compounds containing a ring of atoms in the nucleus. cy·clic or cy·cli·cal adj. 1. temperature patterns found in outdoor exposures. Still, opportunities exist to control some variables in outdoor exposure without introducing artificial or unnatural weathering conditions. In this DOE, the design achieved control over two factors without introducing artificial and unnatural environments: the exposure angle and exposure location factors. The third factor--moisture--required an artificial application of moisture spray. The Moisture Variable In order to characterize the effect of moisture in this DOE, four of the eight trials exposed specimens on racks with water spray. Essentially identical to non-spray racks except for the moisture, the spray racks applied a light rain-like water spray on exposed specimens. A spray nozzle A spray nozzle is a device that facilitates the formation of spray. When a liquid is dispersed as a stream of droplets (atomization), it is called a spray. The typical purpose of the spray is to maximize the effect of the liquid by increasing the total surface area for better applied high purity de-ionized water to wet specimens exposed on spray racks. A single spray event lasted 60 sec. Eight spray events occurred at the beginning of each hour from 08:00 hr until 16:00 hr during each day of the exposure. Trials shown in Figure 1 with the moisture spray variable set high (+) exposed specimens on spray racks while trials with the moisture spray variable set low (-) exposed specimens on racks with no spray. In this way, the DOE characterized the effect of an artificially introduced moisture spray on the weathering degradation of the auto paint systems. [FIGURE 2 OMITTED] It is interesting to consider some of the co-variables associated with the moisture spray factor in this experiment. The eight controlled one-minute sprays represent one source of the moisture in this experiment. However, another important source of moisture co-varies with the location factor and the angle factor. Figure 2 shows naturally occurring approximate time of wetness for Arizona and Florida at 5[degrees] and 45[degrees] exposure angles during an early period of the exposures. Both location and angle appear to affect the naturally occurring time of wetness. Almost every night, moisture condensed con·dense v. con·densed, con·dens·ing, con·dens·es v.tr. 1. To reduce the volume or compass of. 2. To make more concise; abridge or shorten. 3. Physics a. from the surrounding sur·round tr.v. sur·round·ed, sur·round·ing, sur·rounds 1. To extend on all sides of simultaneously; encircle. 2. To enclose or confine on all sides so as to bar escape or outside communication. n. air mass immerses exposed specimens under millimeters of liquid water in southern Florida. The Exposure Angle Variable In order to characterize the effect of exposure angle in this DOE, four of the eight trials exposed specimens on racks oriented o·ri·ent n. 1. Orient The countries of Asia, especially of eastern Asia. 2. a. The luster characteristic of a pearl of high quality. b. A pearl having exceptional luster. 3. 45[degrees] from the horizontal facing true south while four trials exposed specimens on racks oriented at 5[degrees] from the horizontal. Trials shown in Figure 1 with the angle variable set high (+) exposed specimens on racks set at 5[degrees] while trials with the angle variable set low (-) exposed specimens on racks set at 45[degrees] This represents an example of controlling a variable in a natural weathering DOE without introducing an artificial effect. In this way, the DOE characterized the effect of changing the exposure angle (and all co-variables associated with exposure angle) on the degradation curves of the auto paint systems. It is interesting to consider some of the co-variables associated with exposure angle. Radiant exposure See: thermal exposure. (sometimes referred to as dose) represents one co-variable associated with exposure angle. Cosine effects vary solar intensities and accumulated ac·cu·mu·late v. ac·cu·mu·lat·ed, ac·cu·mu·lat·ing, ac·cu·mu·lates v.tr. To gather or pile up; amass. See Synonyms at gather. v.intr. To mount up; increase. radiation with changing exposure angle. Figures 3 and 4 show this effect of the total solar radiant exposure and total ultraviolet An invisible band of radiation at the upper end of the visible light spectrum. With wavelengths from 10 to 400 nm, ultraviolet starts at the end of visible light and ends at the beginning of X-rays. The primary source of ultraviolet light is the sun. radiant exposure respectively during the experiment. Exposures at 45[degrees] in Arizona accumulated total solar radiant exposure (dose) slightly faster than at the 5[degrees] exposure angle. The 34[degrees] latitude latitude, angular distance of any point on the surface of the earth north or south of the equator. The equator is latitude 0°, and the North Pole and South Pole are latitudes 90°N and 90°S, respectively. of the Arizona exposure site is closer to the 45[degrees] exposure angle than the 5[degrees] exposure angle under the relatively clear Arizona sky and accounts for the faster rate (see Figure 3). On the other hand, observations in southern Florida show little differences in total solar radiant exposures between 5[degrees] and 45[degrees] exposure angles. The 26[degrees] North latitude exposure location is close to the median between summer and winter solstice winter solstice n. In the Northern Hemisphere, the solstice that occurs on or about December 22. winter solstice Noun in southern Florida. Additionally, a much more diffuse diffuse /dif·fuse/ 1. (di-fus´) not definitely limited or localized. 2. (di-fuz´) to pass through or to spread widely through a tissue or substance. dif·fuse adj. sky dome in southern Florida (compared to Arizona) may help average direct and diffuse total solar radiant exposure, as shown in Figure 3. [FIGURE 3 OMITTED] Exposures at 5[degrees] in Arizona accumulated UV (ultraviolet) radiant exposure (dose) faster than at the 45[degrees] exposure angle in Arizona. Specimens exposed at 5[degrees] see more of the north sky dome than specimens exposed at 45[degrees]. Diffuse UV energy reflects from aerosol aerosol (âr`əsōl,–sŏl): see colloid. aerosol System of tiny liquid or solid particles evenly distributed in a finely divided state through a gas, usually air. particles in the north part of the sky dome back to specimens exposed at 5[degrees]. This diffuse light scattering scattering In physics, the change in direction of motion of a particle because of a collision with another particle. The collision can occur between two charged particles; it need not involve direct physical contact. effect is more pronounced for shorter wavelengths (UV) and explains why the earth's sky appears blue. For the same reason, 5[degrees] UV radiant exposure in southern Florida accumulates faster than the 45[degrees] UV radiant exposure in southern Florida (see Figure 4). [FIGURE 4 OMITTED] [FIGURE 5 OMITTED] [FIGURE 6 OMITTED] [FIGURE 7 OMITTED] [FIGURE 8 OMITTED] [FIGURE 9 OMITTED] [FIGURE 10 OMITTED] [FIGURE 11 OMITTED] The Exposure Location Variable In order to characterize the effect of exposure location in this DOE, four of the eight trials exposed specimens in southern Florida while the other four trials exposed specimens in desert Arizona. Trials shown in Figure 1 with the location variable set high (+) exposed specimens at Atlas Atlas, in Greek mythology Atlas (ăt`ləs), in Greek mythology, a Titan; son of Iapetus and Clymene and the brother of Prometheus. Material Testing Technology's South Florida outdoor site located at 25[degrees] 47' North latitude, 80[degrees] 50' West longitude longitude (lŏn`jĭt  d'), angular distance on the earth's surface measured along any latitude line such as the equator east or west of the prime meridian. , while trials with the location variable set low
(-) were exposed at Atlas Material Testing Technology's central
Arizona outdoor site located at 33[degrees] 54' North latitude,
112[degrees] 81' West longitude. This represents another example of
controlling a variable in a natural weathering DOE without introducing
artificial effects. In this way, the DOE characterized the effect of
changing the exposure location (and all co-variables associated with
these locations) on the degradation curves.
By changing exposure variables in this manner, the DOE obtained the following sets of weathering exposure information: four trials with water spray, four trials without water spray, four trials exposed at 5[degrees] angle, four trials exposed at 45[degrees] angle, four trials exposed in Florida, and four trials exposed in Arizona (for a total of 24 trials worth of data) by only actually performing eight trials. This power and efficiency of orthogonally balanced DOE trials represents one reason DOE approaches are especially suitable for weathering experiments. It is important to remember, however, that while researchers may control input variables for natural weathering DOEs, the natural environment may also affect study variables. Researchers must utilize considerable experience and skill to understand the interplay in·ter·play n. Reciprocal action and reaction; interaction. intr.v. in·ter·played, in·ter·play·ing, in·ter·plays To act or react on each other; interact. between effects caused by man and effects caused by nature in the environment within which the experiment is being performed. [FIGURE 12 OMITTED] MATERIALS AND DEPENDENT VARIABLES Automotive Paint Systems Within each exposure trial, the DOE exposed four "replicates" of commercially available automotive paint specimens. Each of the four replicates had the same formulation formulation /for·mu·la·tion/ (for?mu-la´shun) the act or product of formulating. American Law Institute Formulation of acrylic acrylic, artificial fiber made from a special group of vinyl compounds, primarily acrylonitrile. Acrylic fibers are thermoplastic (i.e., soften when heated, reharden upon cooling), have low moisture regain, are low in density, and can be made into bulky fabrics. melamine melamine (mĕl`əmēn'), common name for 2,4,6-triamino-1,3,5-triazine. Melamine is a trimer (see polymer) of cyanamide, H2NC≡N, and is synthesized from calcium carbide. clear topcoat. Each of the four replicates had a different color basecoat: red, yellow, green, and blue. Each of the replicates came from a different manufacturing batch of specimens. By introducing some variation into the specimens via different color basecoats and manufacturing batches, the DOE captured information about the effect of this variation on the clearcoat performance and compared the effects of replicate rep·li·cate v. 1. To duplicate, copy, reproduce, or repeat. 2. To reproduce or make an exact copy or copies of genetic material, a cell, or an organism. n. A repetition of an experiment or a procedure. variation (as experiment error) to the effects of the study variables (moisture spray, angle, and location). Additionally, the DOE captured information on the effects of the study variables across several different colors of paint system rather than limit interpretation of results to only a single color. The screening experiment publication fully describes the clearcoats exposed in this experiment. (13) [FIGURE 13 OMITTED] Appearance Measurements Gloss represents an important characteristic of automotive paint systems and the auto industry widely studies gloss weathering degradation of automotive coatings. (14,15) Technicians performed 20[degrees] gloss measurements on each replicate of each trial every three months in accordance Accordance is Bible Study Software for Macintosh developed by OakTree Software, Inc.[] As well as a standalone program, it is the base software packaged by Zondervan in their Bible Study suites for Macintosh. with ASTM ASTM abbr. American Society for Testing and Materials D 523-89. (16) Since the results and analysis did not show any analytical analytical, analytic pertaining to or emanating from analysis. analytical control control of confounding by analysis of the results of a trial or test. advantage by using delta gloss or percent gloss loss, this report presents actual measured gloss values. The same type of clear coating on the different replicates showed approximately the same initial values. Technicians measured gloss at the two different exposure locations using the same model gloss meters and identical measurement procedures including frequent calibrations during measurements. RESULTS AND ANALYSIS Figures 5 through 12 show the results of the eight trials in this weathering DOE as the degradation curves, through 96 months of exposure. Gloss measurements were not performed on the specimens until 30 months after the exposures started. Some of the curves show a portion of the function indicative of rate dependent degradation (slope) followed by a leveling off of the curve once some level of degradation had been achieved. Because of this characteristic of the degradation curves, analysis of the data at different points in time can drastically affect the results. For example, analyzing data after all the trial specimens have completely degraded de·grad·ed adj. 1. Reduced in rank, dignity, or esteem. 2. Having been corrupted or depraved. 3. Having been reduced in quality or value. will show no effects of the study variables. For this reason, the DOE included analysis at two points in the exposure period before the degraded condition had been reached in all the trials. Having the degradation curves to visually inspect, the 45- and 60-month intervals were chosen for analysis. DOE is primarily a logic tool. The logic includes comparing or contrasting the set of trials with the specific factor of interest set low to the set of trials with the same factor set high. Figure 13, adapted from Montgomery, (12) illustrates this logic for this weathering DOE. (10) The analysis calculates the effect of factor A (spray) by determining an average of the four trials with no spray (low, A-), determining an average of the four trials with spray (high, A+), and finding the difference between these two averages. The analysis uses the same procedure to calculate the effect of factor B (angle), but, contrasts different sets of trials to determine the effect of angle. The analysis contrasts factor C (location) along a third axis of the the diameter of the sphere which is perpendicular to the plane of the circle. See also: Axis experimental volume. In this manner, the analysis reveals information regarding the effects of each variable, as well as interactions in a robust manner from only eight trials in this experiment. The mechanics of DOE analysis are fairly standardized standardized pertaining to data that have been submitted to standardization procedures. standardized morbidity rate see morbidity rate. standardized mortality rate see mortality rate. and widely published. The Barrentine reference fully documents the analytical procedures Analytical Procedures is one of financial audit skill which help an auditor understand the client's business and changes in the business, to identify potential risk areas and to plan other audit procedures. used in this study. (9) The analysis tables in Figure 14 for 45 months and Figure 15 for 60 months follow Barrentine's approach very closely. [FIGURE 16 OMITTED] [FIGURE 17 OMITTED] OBSERVATIONS Observations at the 45-Month Interval The analysis reveals several critical observations shown in Figure 14. Spray (A) had, by far, the largest effect on the gloss. Location (C) also showed a significant effect. Angle (B) showed only a marginal effect. Spray (A) interacted significantly with location (C). Spray did not affect gloss degradation in southern Florida as it did in Arizona. A similar interaction also appeared between spray (A) and angle (B). The analysis also indicates the possibility of a three-way interaction between spray (A), angle (B), and location (C) (however, the level of this effect appears very close to the decision limits for significance). Additionally, spray (A) and location (B), as well as their interaction, show a significant effect on the variation observed in the data. Observations at the 60-Month Interval Several observations can be made from the analysis shown in Figure 15. Spray (A) had, by far, the largest effect on the gloss. Location (C) showed only a marginal effect. The analysis also indicated the possibility of an interaction between spray and location. Additionally, spray (A) and location (C), as well as their interaction, show a significant effect on the variation observed in the data. The results of the main effects analysis for 60 months are graphed in Figure 16, showing the effect of the spray, angle, and location factors studied in this experiment. The results of the interaction effects for 60 months are graphed in Figure 17, showing the interaction between the spray (A) and location (B) factors in this experiment. CONCLUSTONS AND CONSIDERATIONS Natural weathering DOEs offer an efficient and robust approach to characterizing natural weathering material degradation. Application of only eight daytime Daytime may refer to:
moisture sprays of one-minute duration showed significant and important effects on the degradation curves of the automotive paint systems exposed in both Arizona and Florida. Application of water sprays dramatically accelerated gloss loss and the effect of these moisture sprays far outweighed the effects due to location and exposure angle. The significant differences in radiant exposure due to different exposure angles did not appear to cause significant effects in this experiment since exposure angle did not show a significant effect on the results. The significant differences in naturally occurring time of wetness due to different exposure angles did not appear to cause significant effects in this experiment since the exposure angle did not appear to have a significant effect on the results. The moisture spray factor appeared to interact with the exposure location factor in this experiment. One-factor-at-a-time (OFAT) experiments may not have characterized the interaction between the moisture spray factor and the exposure location factor. Applying moisture sprays in artificial weathering methods may have dramatic effects on the results and conclusions. "Incorrect" simulation of the moisture factor in artificial weathering may impact results and conclusions from the tests. Simulating the interaction of the moisture factor and location factors observed in this study may prove especially difficult to simulate simulate - simulation under highly artificial laboratory weathering test methods. ACKNOWLEDGMENT acknowledgment, in law, formal declaration or admission by a person who executed an instrument (e.g., a will or a deed) that the instrument is his. The acknowledgment is made before a court, a notary public, or any other authorized person. The author would like to thank the technicians at Atlas Weathering Services Group's DSET DSET Desert Sunshine Exposure Testing Inc. and EvTL facilities for the exposure testing and gloss measurements. Refernces (1) Pickett, J.E. and Umamaheswaran, V., "Highly Predictive Accelerated Weathering of Engineering Thermoplastics," SAE sae abbr (BRIT) (= stamped addressed envelope) → sobre con las propias señas de uno y con sello technical paper 2003-01-1192, Society of Automotive Engineers SAE International (SAE) is a professional organization for mobility engineering professionals in aerospace, automotive and the commercial vehicle industries. The Society is a standards development organization for the engineering of powered vehicles of all kinds, including , March, 2003. (2) Bank, R., "Study Shows Differences in Weatherability of Universal Grades in White Paint," PCI (1) (Payment Card Industry) See PCI DSS. (2) (Peripheral Component Interconnect) The most widely used I/O bus (peripheral bus). (September 1997). (3) "SAE J1960 Accelerated Exposure of Automotive Exterior Materials Using a Controlled Irradiance Water-Cooled Xenon xenon (zē`nŏn) [Gr.,=strange], gaseous chemical element; symbol Xe; at. no. 54; at. wt. 131.29; m.p. −111.9°C;; b.p. −107.1°C;; density 5.86 grams per liter at STP; valence usually 0. Arc Apparatus," 2003 SAE Handbook, Vol. 1, Society of Automotive Engineers, Inc., Wavendale, PA, 2003. (4) Hardcastle, H.K., "Considerations for Relating Artificial Laboratory and Natural Outdoor Weathering Durability Testing," Proc. Annual Technical Conference of The Society of Plastics Engineers (ANTEC), Chicago, 2004. (5) "ASTM G90-94 Practice for Performing Accelerated Outdoor Weathering of Nonmetallic non·me·tal·lic adj. 1. Not metallic. 2. Chemistry Of, relating to, or being a nonmetal. Adj. 1. Materials Using Concentrated Natural Sunlight," 1994 Annual Book of ASTM Standards, Vol. 14.02, American Society for Testing and Materials, West Conshohocken, PA, 1994. (6) Nguyen, T, et al, "Relating Laboratory and Outdoor Exposure of Coatings: II. Effects of Relative Humidity on Photodegradation and the Apparent Quantum Yield The quantum yield of a radiation-induced process is the number of times that a defined event occurs per photon absorbed by the system. Thus, the quantum yield is a measure of the efficiency with which absorbed light produces some effect. of Acrylic-Melamine Coatings," J. COAT. TECHNOL., 74, No. 932, 65 (2002). (7) Misovski, T., Nichols, M.E., and Hardcastle, H.K., "The Influence of Water on the Weathering of Automotive Paint Systems," Proc. 4th International Symposium symposium In ancient Greece, an aristocratic banquet at which men met to discuss philosophical and political issues and recite poetry. It began as a warrior feast. Rooms were designed specifically for the proceedings. on Service Life Prediction, National Institute for Standards and Technology, Key Largo Key Largo, narrow island, c.30 mi (48 km) long, off S Fla., largest of the Florida Keys. Along with other Florida Keys, especially Key West, it has become an increasingly popular tourist spot, noted for its scuba diving, nightlife, and beachside resorts. , FL, 2006. (8) Pianka, E., Evolutionary Ecology Evolutionary ecology lies at the intersection of ecology and evolutionary biology. It approaches the study of ecology in a way that explicitly considers the evolutionary histories of species and the interactions between them. , 2nd Ed., Harper & Row, New York New York, state, United States New York, Middle Atlantic state of the United States. It is bordered by Vermont, Massachusetts, Connecticut, and the Atlantic Ocean (E), New Jersey and Pennsylvania (S), Lakes Erie and Ontario and the Canadian province of , 1978. (9) Barrentine, L.B., An Introduction to Design of Experiments--A Simplified Approach, ASQ ASQ American Society for Quality ASQ Arab Studies Quarterly ASQ Automated Software Quality ASQ Administrative Science Quarterly ASQ Ages & Stages Questionnaires ASQ Allowable Sale Quantity ASQ Ascension Island (DoD radar) Quality Press, Milwaukee, 1999. (10) Hardcastle, H.K., "Applying Taguchi Designs to EMMAQUA Experiments," Proc. 4th International Symposium on Weatherability, Materials Life Society, Kanagawa University, Japan, 2000. (11) Hardcastle, H.K., "Understanding the Effects of Weathering Variables on Plastics Using Fractional Factorial Experiments," Proc. Annual Technical Conference of The Society of Plastics Engineers (ANTEC), Orlando, 2000. (12) Montgomery, D.C., Design and Analysis of Experiments, 3rd Ed., John Wiley John Wiley may refer to:
(13) Hardcastle, H.K. "Characterizing the Effect of Weathering Variables Using Accelerated Fractional Factorial Experiments," in Natural and Artificial Ageing of Polymers, Reichert, T. (Ed.), Publication No.5, Gesellschaft fur Umweltsimulation, Germany, 2004. (14) Bauer, D.R., "Chemical Criteria for Durable Automotive Topcoats," J. COAT. TECHNOL., 66, No. 835, 57 (1994). (15) Adamsons, K., "Chemical Depth Profiling of Automotive Coating Systems Using Slab Microtome microtome /mi·cro·tome/ (mi´krah-tom) an instrument for cutting thin sections for microscopic study. mi·cro·tome n. Sectioning with IR/UVVIS Spectroscopy spectroscopy Branch of analysis devoted to identifying elements and compounds and elucidating atomic and molecular structure by measuring the radiant energy absorbed or emitted by a substance at characteristic wavelengths of the electromagnetic spectrum (including gamma ray, and Optical Microscopy microscopy /mi·cros·co·py/ (mi-kros´kah-pe) examination under or observation by means of the microscope. mi·cros·co·py n. 1. The study of microscopes. 2. ," J. COAT. TECHNOL, 74, No. 924, 47 (2002). (16) "Standard Test Method for Specular spec·u·lar adj. Of, resembling, or produced by a mirror or speculum. spec  u·lar·ly adv.Adj. 1. Gloss," ASTM D 523-89, Annual Book of ASTM Standards, Vol. 6.01, American Society for Testing and Materials, Philadelphia, 1998. by Henry K. Hardcastle III Atlas Material Testing Technology LLC (Logical Link Control) See "LANs" under data link protocol. LLC - Logical Link Control * Presented at the 3rd European Weathering Symposium, Confederation A union of states in which each member state retains some independent control over internal and external affairs. Thus, for international purposes, there are separate states, not just one state. of European Environmental Engineering Societies, September 13-14, 2007, Krakow, Poland. *45601 N. 47th Ave., Phoenix, AZ 85087-7042.
Figure 14 -- DOE Analysis: 45 Months, 20[degrees] Gloss
Trials A-Spray B-Angle C-Location AB AC
1 - - - + +
2 + - - - -
3 - + - - +
4 + + - + -
5 - - + + -
6 + - + - -
7 - + + - -
8 + + + + +
SUM (+) 160 229 190 233 199
SUM (-) 281 213 252 209 243
AVG (+) 40 57 47 58 50
AVG (-) 70 53 63 52 61
Effect -30 4 -16 6 -11
Avg [S.sub.+.sup.2] 34.23 14.92 4.65 13.65 3.54
Avg [S.sub.-.sup.2] 3.90 23.21 33.48 24.28 34.58
F 8.79 1.56 7.21 1.79 9.76
Trials BC ABC Y (AVG) [S.sup.2]
1 + - 74 0.92
2 + + 45 82.67
3 - + 71 4.67
4 - - 62 45.67
5 - + 69 4.33
6 - - 25 4.92
7 + - 68 5.67
8 + + 29 3.67
SUM (+) 215 213
SUM (-) 226 229
AVG (+) 54 53
AVG (-) 57 57
Effect -3 -4
Avg [S.sub.+.sup.2] 23.23 23.83
Avg [S.sub.-.sup.2] 14.90 14.29
F 1.56 1.67
Raw Data
Rep 1 Rep 2 Rep 3 Rep 4
75 75 74 73
45 57 35 43
72 73 68 71
63 70 54 59
66 71 68 69
27 22 26 26
67 71 66 66
29 31 27 27
[S.sub.E.sup.2] = 19.06 N = 32
[S.sub.E] = 4.37 [S.sub.eff] = 1.54
D.L. = +/- (t) ([S.sub.eff]) 3.17989
df = (#obs/run-1) x #runs (trials) = 3 x 8 = 24
t24 = 2.06
D.L. F (12/12) = 2.69
Figure 15 -- DOE Analysis: 60 Months, 20[degrees] Gloss
Trial A-Spray B-Angle C-Location AB AC
1 - - - + +
2 + - - - -
3 - + - - +
4 + + - + -
5 - - + + -
6 + - + - +
7 - + + - -
8 + + + + +
SUM (+) 104 192 175 194 168
SUM (-) 266 178 195 176 202
AVG (+) 26 48 44 48 42
AVG (-) 66 45 49 44 50
Effect -40 3 -5 4.4 -8
Avg [S.sub.+.sup.2] 56.98 46.73 4.15 46.48 7.06
Avg [S.sub.-.sup.2] 6.21 16.46 59.04 16.71 56.13
F 9.18 2.84 14.24 2.78 7.95
Trial BC ABC Y (AVG) [S.sup.2]
1 + - 66 8.25
2 + + 26 50.92
3 - + 63 10.00
4 - - 40 167.00
5 - + 68 3.67
6 - - 19 3.00
7 + - 69 2.92
8 + + 21 7.00
SUM (+) 181 177
SUM (-) 189 193
AVG (+) 45 44
AVG (-) 47 48
Effect -2 -4.1
Avg [S.sub.+.sup.2] 17.27 17.90
Avg [S.sub.-.sup.2] 45.92 45.29
F 2.66 2.53
Raw Data
Rep 1 Rep 2 Rep 3 Rep 4
67 70 64 64
29 34 18 22
64 67 60 61
39 57 26 36
67 69 65 69
19 16 20 19
68 71 67 69
21 24 18 19
[S.sub.E.sup.2] = 31.59 N = 32
[S.sub.E] = 5.62 [S.sub.eff] = 1.99
D.L. = +/- (t) ([S.sub.eff]) 4.093764
df = (#obs/run-1) x #runs (trials) = 3 x 8 = 24
t24 = 2.06
D.L. F (12/12) = 2.69
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