Opaque Paint Research Articles

Effect of treatment temperature on the initial performance of layers of water-based paints in heat-treated pine and beech wood

Hardness, surface roughness, and adhesion strength were determined for water-based opaque paints applied to heat-treated wood material surfaces. For this purpose, Scotch pine (Pinus sylvestris L.) and beech (Fagus orientalis Lipsky) woods were used as experimental material. Specimens were subjected to heat treatment at 3 different temperatures (150, 180, and 210 °C) and 2 different periods (2 and 4 h) under laboratory conditions. Two-component water-based paints with commercial codes D17 and D45 were applied to the surfaces. The hardness, surface roughness, and adhesion strength values of painted samples were determined according to the applicable standards. The results showed that there were higher values of hardness and surface roughness of water-based paints in short-term heat treatment compared with long-term heat treatment. A general decrease in pine with D17 and D45 paints applied to the surfaces and in beech with D45 in adhesion strength was detected depending on the increasing heat treatment temperature and duration. An increase was observed in beech samples with D17 paint applied.

Enforcing Kubelka–Munk constraints for opaque paints

AbstractThe Kubelka–Munk model relates the colours of paint mixtures to the absorption and scattering coefficients (K and S) of the constituent paints, and to their concentrations (C) in the mixtures. All Ks and Ss are non‐negative, and Cs are physically constrained to be between 0 and 1. Standard estimation procedures cast the Kubelka–Munk relationships as an overdetermined linear system and apply ordinary least squares (OLS). OLS, however, sometimes produces coefficients or concentrations that are less than 0 or greater than 1. These physically impossible solutions occur because OLS projects a target vector (such as a desired reflectance spectrum) onto a vector subspace, while in fact the set of physically realisable paint combinations is a convex polytope, which is a subset of that subspace. This paper reformulates Kubelka–Munk estimation problems geometrically, as the problem of finding the point on that polytope which is closest to a target vector. The solutions to the reformulated problem are always physically realisable. If feasible, a worker could solve the reformulated problem with a ready‐made commercial solver. Otherwise, the Gilbert–Johnson–Keerthi algorithm is recommended as particularly suitable for Kubelka–Munk estimation; this algorithm has been tested on some simple cases and released as open‐source code.

Mathematical and empirical evaluation of accuracy of the Kubelka–Munk model for color match prediction of opaque and translucent surface coatings

Attempts were made to evaluate mathematically and empirically the accuracy of the Kubelka–Munk model for color match prediction of opaque and translucent surface coatings in the color using industries. To this end, an innovative inversed mathematical evaluation procedure was concocted which comprised of plotting the absorption and scattering constants of the Kubelka–Munk model or any of its various modified form or replacements theories against the intrinsic optical coefficients of the respective exact radiation transfer theories, namely Chandrasekhar for opaque and van de Hulst for translucent media. The results prove mathematically that the Kubelka–Munk model for opaque media is a sound theory and its various suggested modifications or replacements do not improve the color match prediction of opaque surface coating media. This mathematical conclusion was further confirmed by color match prediction of actual opaque paint samples. On the other hand, the mathematical prediction for translucent media illustrated a completely different picture, depicting nonlinearity between the optical constants and the respective concentrations of colorants. This implies that much further work has to be carried out to derive invertible new equations to enforce linearity to such situations or make use of alternative artificial intelligent procedures which are designed especially for nonlinearity.

Femur, tibia and fibula bone templates to estimate subject-specific knee ligament attachment site locations

In-vivo estimates of the positions of knee ligament attachment sites are crucial for subject-specific knee modelling. The present study provides template digital models of femur, tibia and fibula that embed the positions of centroids of the origins and insertions of cruciate and collateral ligaments, along with information on their dispersion related to inter-individual variability. By using a shape transformation procedure of choice, these templates can be made to match anatomical information measured on a subject under analysis. Generic bone digital models of the femur, tibia and fibula were first chosen as bone templates. Ligament attachment areas were accurately identified through dissection on the bones of 11 knee specimens, and marked using radio opaque paint. Digital models of these bones embedding the positions of the centroids of the identified ligament attachment areas were thereafter obtained using medical imaging techniques. These centroids were mapped onto the relevant bone template, thus obtaining a cloud of 11 points for each attachment site, and descriptive statistics of the position of these points were thereafter determined. Dispersion of these positions, essentially due to inter-individual variability, was below 6mm for all attachment areas. The accuracy with which subject-specific ligament attachment site positions may be estimated using the bone template models provided in this paper was also assessed using the above-mentioned 11 specimens data set, and a leave-one-out cross validation approach. Average accuracy was found to be 3.3±1.5mm and 5.8±2.9mm for femoral and tibial/fibular attachment sites, respectively.

A new method for the evaluation of the end-to-end distance of the knee ligaments and popliteal complex during passive knee flexion

BackgroundAccurate knowledge about the length variation of the knee ligaments (ACL, PCL, MCL and LCL) and the popliteal complex during knee flexion/extension is essential for modelling and clinical applications. The aim of the present study is to provide this information by using an original technique able to faithfully reproduce the continuous passive knee flexion–extension kinematics and to reliably identify each ligament/tendon attachment site. MethodsTwelve lower limbs (femur, tibia, fibula, patella) were tested and set in motion (0–120°) using an ad hoc rig. Tibio-femoral kinematics was obtained using an optoelectronic system. A 3D digital model of each bone was obtained using low-dosage stereoradiography. Knee specimens were dissected and the insertion of each ligament and popliteal complex were marked with radio opaque paint. ACL, PCL and MCL were separated into two bundles. Bone epiphyses were CT-scanned to obtain a digital model of each ligament insertion. Bones and attachment site models were registered and the end-to-end distance variation of each ligament/tendon was computed over knee flexion. ResultsA tibial internal rotation of 18°±4° with respect to the femur was observed. The different bundles of the ACL, MCL and LCL shortened, whereas all bundles of the PCL lengthened. The popliteal complex was found to shorten until 30° of knee flexion and then to lengthen. ConclusionThe end-to-end distance variation of the knee ligaments and popliteal complex can be estimated during knee flexion using a robust and reliable method based on marking the ligaments/tendon insertions with radiopaque paint. Level of evidenceLevel IV

Outdoor weathering performance parameters of exterior wood coating systems on tropical hardwood substrates

Wood coating research almost exclusively focuses on softwood as substrate despite the fact that coatings applied on tropical hardwoods show a different weathering behaviour. The objective of this study was to quantify the impact of wood substrate and coating type on the weathering behaviour of finished wooden joinery in outdoor exposure using a set of statistical methods. Therefore, a broad range of white opaque paints and mid-oak semi-transparent stains were used. The coatings were industrially applied on window frames made of frequently used commercial tropical hardwood species. The general appearance of the wood/coating systems was assessed visually using a rating scale that takes into account the anatomical characteristics of hardwood. For the evaluation, a required minimum exposure time of 2.5 years outdoor weathering for joinery in vertical position and facing south-west was determined. At 30 months best performances were recorded for waterborne alkyd primers with an acrylic topcoat when dry coating film was sufficiently thick. The dry layer thickness also affected the impact of the hiding power on the performance of the wood/coating system. Within hardwood species the degradation rate of coatings on species with a fine texture was the lowest. The significant influence of the substrate’s texture on the weathering behaviour of coated hardwood stressed the need to evaluate the wood/coating system in total.

Opaque paints based on a water emulsion of ÉD-20 resin for decorating glass articles

It is shown that water epoxy emulsions can be used as a binder to obtain paints for decorating glass articles. The physical-chemical properties of epoxy coatings are studied.

Wing wear is a poor estimate of age in Cerceris fumipennis (Hymenoptera, Crabronidae)

The native, ground nesting, beetle hunting philanthine wasp Cerceris fumipennis Say is in development as a biosurveillance tool to detect Emerald Ash Borer (Agrilus planipennis) and other pest Buprestidae threatening the forests of North America (Marshall et al. 2005; Careless and Marshall 2010; Nalepa and Swink 2011). As part of that effort the North Carolina (NC) Department of Agriculture & Consumer Services has been working to determine the phenology and life history of C. fumipennis in the state, primarily to determine its activity overlap with prey species of interest. An examination of specimens in the NC State University Insect Museum indicated that C. fumipennis had been collected in Wake County, NC, as early as 24 May and as late as 22 September between 1921 and 1982, and Kurczewski and Miller (1984) noted that C. fumipennis probably has a partial second brood in the south. Observations of wing wear of C. fumipennis females in Wake County during 2009 suggested that there may be either an extended emergence of a single generation, or that more than one generation per year occurs in the state. During the third week of July, females with completely intact wings as well as females with severely damaged wing margins were both present in the same nesting aggregation. In 2010 a study was conducted at that aggregation, a baseball diamond in the Raleigh City Parks system, to determine if wing wear in C. fumipennis may be positively correlated with female age. Shortly after nests began appearing at the site (30 May), females were captured and given a unique mark on the thorax using DecoColor opaque paint markers (Fig. 1a). A picture of each marked female’s right wing was taken with a Sony Cybershot JHR 24: 43–46 (2012)

Small Fry (review)

Reviewed by: Small Fry Deborah Stevenson Adoff, Jaime. Small Fry; illus. by Mike Reed. Dutton, 2008 [32 p] ISBN 978-0-525-46935-3 $16.99 Reviewed from galleys Ad 5–8 yrs This collection of nineteen poems focuses mostly on the experience of being small in a world of grownups and taller kids. Some poems talk about adaptations (in “Movie,” “Dad brings encyclopedia/ A through C, props me up so I can see”), some about advantages (“My four foot frame/ built just for this game,” says the narrator of “Air Shortness” about dodgeball), and some just about general experiences of childhood (“Parent-Teacher Conference,” “Sleep Over”). The free-verse poems are uneven and a little prosy, with some of them rather generic; standout entries are those such as “Movie” and “Small Soldier,” which possess a compact theme-relevant story. Opaque paints textured with mottled strokes give the figures sturdy dimensionality; the faces of the multicultural cast are blandly similar, but the kids are situated in lively child-friendly landscapes suitable for reflection on their status and stature. This isn’t going to dethrone the likes of Florian or Prelutsky, but it’ll offer some humorous sympathy to young audiences, who are keenly aware of the disadvantages of being smaller. Copyright © 2008 The Board of Trustees of the University of Illinois

Single‐constant simplification of Kubelka‐Munk turbid‐media theory for paint systems—A review

AbstractFor opaque coloration systems, Kubelka‐Munk turbid media theory is used commonly to model optical mixing behavior. Most educational publications on the subject use opaque paint systems when describing the two‐constant approach and textile systems when describing the single‐constant simplification. Because of the differences in defining concentration for these systems and the corresponding degrees of freedom, the single‐constant simplification for paint and textile systems are not identical. The second edition of “Principles of Color Technology” showed a numerical example for an opaque paint system modeled using the textile equations. The third edition used the same example but modified the degrees of freedom, a hybrid of the paint and textile approaches. Recent research by Berns and Mohammadi has evaluated the single‐constant simplification for modeling artist paints; they have used both the hybrid and paint approaches. Thus, it was of interest to review these different approaches and determine whether these differences have practical importance and whether future printings and editions of Principles of Color Technology should be modified. The three approaches were tested for tints made from a mixture of cobalt blue and titanium white acrylic emulsion artist paints. The differences between the textile and hybrid approaches were inconsequential. The paint approach was superior and its use is recommended for opaque paint systems. The differences in the numerical example from Principles of Color Technology were very small. For future printings of the third edition, the example will remain unchanged. For future editions, including the numerical example remains an open question. © 2007 Wiley Periodicals, Inc. Col Res Appl, 32, 201–207, 2007

Experimental tests of dropwise cooling on infrared-transparent media

The present work is aimed at analyzing the cooling of hot solid surfaces induced by liquid droplets. In particular, the study is focused on the non-intrusive measurement of the transient contact temperature between impinging droplets and hot solid surfaces. An experimental apparatus was built and set up in order to approach the non-trivial problem of the measurement of a solid–liquid interface temperature after droplet impingement. The solid–liquid interface temperature was monitored from below through a transparent-to-infrared material. That material had been coated with a very thin layer of high-emissivity, opaque paint on its upper side, so that it could effectively respond to the infrared camera located below. The paper reports the main results that have been collected to date, with particular regard to the approaches used to coat the transparent solid. Some considerations are also expressed about the effectiveness of the proposed method and about the improvements that are currently being implemented to get new and more accurate interface temperature measurements.

Detection and electrical characterization of hidden layers using time-domain analysis of terahertz reflections

We use a time-domain analysis method to characterize the outer layer of a multilayer structure regardless of the inner ones, thus simplifying the characterization of all the layers. We combine this method with THz reflection spectroscopy to detect nondestructively a hidden aluminum oxide layer under opaque paint and to measure its conductivity and high-frequency dielectric constant in the THz range.

Sites of photoperception in white clover

AbstractWhite clover (Trifolium repens) grows both horizontally, via the stolon, and vertically, via the petiole, through its environment. Comparing the effects of clear and opaque paint allowed the localization of two photoperceptive sites. Stolon growth (horizontal) was altered by the radiation environmental the node, and petiole growth (vertical) by radiation perceived at the petiole tip. Photoperception these two sites provides a mechanism by which the plant can direct its growth to exploit its environment maximally.

A Physically Based Colour Model

We propose an intuitively simple way of representing colour which has the additional virtue that, it permits mixing and overlaying of transparent and opaque paints to an arbitrary degree. Our approach is related to the earlier alpha channel model used for compositing. It includes this as a special case but has applications in many other areas, especially animation, paint programs and graphics libraries.

ヒト歯肉微小領域より得られる光電脈波

We have established a method to observe circulation in a small area of the human gingiva. Reflected light photo-plethysmographs (RLP) and transilluminated light photo-plethysmographs (TLP) were recorded from healthy gingiva in 2 young adults of twenties. A tungsten-lamp, connected to a stabilized power source, was used to illuminate the gingiva. The reflected or transilluminated light was collected using a fibre-optic bundle. A CdSe photo-conductive cell was used as the photo-detector. The ECG was recorded simultaneously. The results were as follows: 1) RLP and TLP were both synchronous with the heart beat and showed a dicrotic-notched wave form. 2) When the light-collecting fibre was 0.5 mm from the surface of the gingiva, the dicrotic notch with TLP was clearer than that with RLP. 3) When the light-collecting fibre was placed less than 0.5 mm from the gingival surface, clear dicrotic notches were seen in RLP. 4) When the surface of the gingiva was covered with white opaque paint to prevent transilluminated light, definite dicrotic notches were observed with RLP. 5) RLP was produced mainly by the pulsation of the gingival surface, and the pulsatile movement of the tooth had a little effect on RLP. 6) RLP was consisted from the light reflected from the surface of the gingiva and also from the light reflected after penetrating some distance in the gingival tissue.

Highlights in substrate protection

After a few introductory remarks on the composition, formulation and application of organic coatings, this paper reviews some special subjects with respect to substrate protection by organic coatings. The substrates discussed are wood, steel, concrete, galvanised steel and paint, each characterised by specific degradation processes. The degradation of wood is caused mainly by moisture, UV radiation and fungi. Substrate protection can be supplied either by transparent coatings or by opaque paints. The protective function of transparent coatings is improved by the incorporation of UV absorbing compounds, and by the use of transparent iron oxides with very small particle sizes. Recent developments in the field of opaque paints include water-borne and highsolids formulations. In the latter case, research is focused on the problems associated with the use of resins with low molecular weights and narrow molecular weight distributions. The effectiveness of protective coatings on steel depends to a large extent on the pretreatment of the surface and the conditions during application. A tendency is seen towards high-solids and solvent-free protective coatings. A point of special interest is the widening of the application window, i.e. the development of materials and processes which allow application under adverse conditions. Two examples are discussed, viz. a recently developed primer curing at low temperatures, and a technique for simultaneous blasting and priming. As an example of concrete protection, a new lining material capable of bridging cracks is discussed. The progressive acidification of the environment necessitates the protection of galvanised steel surfaces by an organic coating. A study has been made of the surface of galvanised steel by means of modern surface-analytical techniques. In many cases paints are applied on existing paint systems. Paint, as a substrate for a new paint system, has its problems, especially with respect to adhesion. Modern techniques are available to study the performance of paint as a substrate.

The Kinetics of Fading: Opaque Paint Films Pigmented with Alizarin Lake and Titanium Dioxide

The physical-chemical principles that govern the fading of pigments have been difficult to discover solely by visual observation of changes in color. The authors' use of precise spectrophotometric reflectance measurements and modern color-matching computations based on the Kubelka-Munk theory have made it possible to demonstrate that the decrease in concentration of alizarin lake (fading) during exposure in a Fade-ometer® follows first-order kinetics. The traditional artists' colorant, alizarin lake, was used as a model of a fugitive organic pigment in mixture with a scattering white pigment, titanium dioxide, applied in a poly (vinyl acetate)-based paint at complete hiding. The experimental results indicate that the red-colored alizarin lake tends to be converted to a yellow form which in turn fades to a colorless condition, also by first-order kinetics. The specific rate of fading is shown to be essentially constant over a wide range of initial concentrations of colorant and of pigment volume concentration.

The Kinetics of Fading: Opaque Paint Films Pigmented with Alizarin Lake and Titanium Dioxide

Abstract The physical-chemical principles that govern the fading of pigments have been difficult to discover solely by visual observation of changes in color. The authors' use of precise spectrophotometric reflectance measurements and modern color-matching computations based on the Kubelka-Munk theory have made it possible to demonstrate that the decrease in concentration of alizarin lake (fading) during exposure in a Fade-ometer® follows first-order kinetics. The traditional artists' colorant, alizarin lake, was used as a model of a fugitive organic pigment in mixture with a scattering white pigment, titanium dioxide, applied in a poly (vinyl acetate)-based paint at complete hiding. The experimental results indicate that the red-colored alizarin lake tends to be converted to a yellow form which in turn fades to a colorless condition, also by first-order kinetics. The specific rate of fading is shown to be essentially constant over a wide range of initial concentrations of colorant and of pigment volume c...

How the two eyes add together: monocular properties of the visually guided orientation behaviour of flies

In this account fixation and the torque response to a transient moving stripe of flying femaleMusca domestica with monocular sight was tested. This was made by either covering one eye of the fly with opaque paint or by placing a screen in front of one side of the fly's visual field. A stripe was moved with constant speed once around the fly clockwise and, after a pause, counterclockwise. The torque response of the fly was measured during the motion of the stripe and shortly beforehand. The results demonstrated that the monocular torque response to progressive (from front to back) motion and regressive (from back to front) motion essentially do not differ from the binocular response, except for the region of bionocular overlap. The beginning of the response of a fly with monocular vision to progressive motion is 11 ° (on average) before the direction of flight (0°), which means that the maximal functional binocular overlap of femaleMusca domestica is stretched at least 15° to each side (3.1). In addition, the shape of the monocular torque response to a progressively moving stripe was determined (see Figs. 5Ia and 5IIb). In other experiments similar to the ones described above, a screen was placed on one side of the fly's visual field or then on the other, (instead of covering one eye) and the torque response to the moving stripe was measured. Using this method, a delay response of 90 ms was measured. We suggest that this is the delay of the direction-sensitive component of the torque response, and therefore an additional argument for the existence of two components for the optomotor torque response. Flies with a covered eye or with a screen placed in front of one side of the visual field were able to fixate a single narrow long black stripe. This, however, was possible only when an additional offset signal was added, in order to give the stripe a constant velocity component. As a result there was a shift of the fixation towards the unobscured eye. The shift was small for the monocular flies, and it was larger (13° on average) when the screen was on one side of the fly. A new type of laser torquethrust transducer was developed and is described.

Mating Response to Visual Stimulus in the Male Codling Moth 1

Male codling moths, Laspeyresia pomonella (L.), were tested to determine if visual stimulus contributed to copulatory response. One group of males had their antennae excised and eyes covered with opaque paint; a 2nd group had their antennae excised; a 3rd group had their eyes covered; and a 4th group that was unaltered in any way. Percentage matings for the treatment groups were 19, 45, and 60, respectively, compared with 87% for the control. The difference between the treatment groups and the control was significant. Vision and other factors contribute to copulatory response in male codling moths.