Detail Reproduction Research Articles

Paper-ink interactions: Microscale droplet absorption into paper for inkjet printing

This thesis concerns paper and ink interactions related to inkjet printing. Themain purpose of this work was to gain a deeper understanding in whichparameters control the flow of ink into papers and how the ink interacts with thepaper surface. The overall objective was to find key parameters to optimize theprint quality in inkjet printing. Characterization of paper-surfaces in terms of porosity, surface roughness andsurface energy was made. Objective and subjective measurements were used forprint quality evaluation. Light microscopy imaging and SEM was used to see howink interacts with the paper surface in a printed image. A high speed camera wasused to study the absorption of picolitre sized inkjet droplets into fine papers.An initial study on the effect of paper properties on print quality was made.Result indicated that there were small differences in print quality for pilot paperswith different composition (in a specific parameter window) and the commercialpaper COLORLOK® reproduced a noticeable high colour gamut compared to theother samples.Research was made to see how surface fixation can affect the print quality forprintouts made with pigmented ink. Surface fixation promotes retention of thepigmented colorant in the outermost surface layer of the paper and has beendenoted “colorant fixation” in this thesis.It was shown that applying colorant fixation onto a paper surface beforeprinting can increase the detail reproduction in a printed image. Differentconcentrations of calcium chloride were applied onto the paper surface on fullscaleproduced non-commercial papers. Test printing was made with a SoHo(Small office/Home office) printer using pigmented ink and results showed thatusing calcium chloride as surface treatment can lead to aggregation of pigments atthe surface resulting in a higher detail reproduction.Fast absorption of the carrier liquid into the paper and fast fixation ofcolourants on the surface is important in inkjet printing to avoid colour to colourbleeding. These demands will be more pronounced when the printing speedincreases. It is important to understand which parameters affect the absorption process tobe able to control the mechanisms and to optimize the print quality.A study of absorption of picolitre size inkjet droplets into fine paper was madein this work. Theoretical equations describing fluid absorption into capillaries weretested and compared with experimental results. The result showed that the timedependence in the Lucas-Washburn (L-W) equation fits fairly well to data whereasthe L-W equation overestimates the penetration depth.The results are directly applicable to paper and printing industry and can beused as a base for future studies of absorption of picolitre sized droplets intoporous materials and for studies of aggregation of colloidal particles on surfaces.

Study on the Printing Performance of Coated Paper Inkjet Ink

In order to evaluate the practical application effect of the self-made water-based coated paper inkjet ink and to study the influence factors, their printing performance and the influence of the printed material for printing performance is studied. The drying time of coated paper ink and ordinary water-based inkjet ink are measured and compared. Drying process of ink droplet is recorded by video contact angle tester. It is found that the drying rate of the coated paper ink is higher than the ordinary ink and the diffusion of the ordinary ink is severe. The coated paper ink and ordinary ink are printed, and it is found that the former can get better image detail and color reproduction for the picture of human’s face and inanimate object. The coated paper ink can also obtain a better reproduction of tone levels. Coated paper inkjet ink is printed on different coated papers, and the color densities are measured through red, green and blue color filter. The color strength and hue error are obtained to evaluate the color characteristics on different papers. It is concluded that the coated paper inkjet ink can obtain better color on the Henglian gloss coated paper, Sunbrite gloss coated paper and SPCO matt coated paper.

An in vitro investigation into the physical properties of irreversible hydrocolloid alternatives

A number of manufacturers have introduced new products that are marketed as alternatives to irreversible hydrocolloid impression materials. However, there is a paucity of laboratory and clinical research on these products compared to traditional irreversible hydrocolloid. The purpose of this study was to evaluate the detail reproduction, gypsum compatibility, and linear dimensional change of 3 recently introduced impression materials designed as alternatives to irreversible hydrocolloid. The tested materials were Position Penta Quick, Silgimix, and AlgiNot. An irreversible hydrocolloid impression material, Jeltrate Plus Antimicrobial, served as the control. The parameters of detail reproduction, gypsum compatibility, and linear dimensional change were tested in accordance with ANSI/ADA Specifications No. 18 and 19. The gypsum compatibility was tested using a type III stone (Microstone Golden) and a type IV stone (Die-Keen Green). The data were analyzed using the Kruskal-Wallis rank test and the Mann-Whitney U test (α=.05). The test materials demonstrated significantly (P<.001) better detail reproduction than the control material. Silgimix exhibited the best compatibility with Microstone, whereas AlgiNot and Position Penta Quick exhibited the best gypsum compatibility with Die-Keen. An incompatibility was observed over time between the Jeltrate control material and the Microstone gypsum material. For linear dimensional change, the mean dimension of the control material most closely approximated the distance between the lines on the test die, but it exhibited the greatest variability in measurements. All of the test materials exhibited linear dimensional change within the ADA's accepted limit of 1.0%. The 3 new impression materials exhibited better detail reproduction and less variability in linear dimensional change than the irreversible hydrocolloid control. Gypsum compatibility varied with the brand of gypsum used, with an incompatibility identified between the control material (Jeltrate Plus Antimicrobial) and Microstone related to surface changes observed over time.

The Utilization of Additional Cassava Starch (Manihot utilisima) for Alginate Dental Impression Material

In Indonesia alginate which is a common impression material used in dentistry is still imported. Since the economic crisis in 1998 the alginate price becoming four times more expensive. This situation resulted in efforts to modify the commercial alginate as had been conducted by a dentist in South Sumatera province in Indonesia. He who had added cassava starch into the commercial alginate used to make partial denture impression. The aim of this research is to investigate the effect of additional cassava starch into the commercial alginate on its ability to produce reproduction detail using type III gypsum the amont of 120 specimens were divided into 6 group of various additional cassava starch 45&ndash;55%. The specimens then being impressed with detail reproduction tool (ISO No. : 1563/1978) and the result is then analyzed under a stereo microscope. Conclusion: the alginate impression material with cassava starch with ratio up to 47,5% can be used as an impression in 50&mu;m and 75&mu;m in depth line. &nbsp; &nbsp;

Linear dimensional changes in plaster die models using different elastomeric materials

Dental impression is an important step in the preparation of prostheses since it provides the reproduction of anatomic and surface details of teeth and adjacent structures. The objective of this study was to evaluate the linear dimensional alterations in gypsum dies obtained with different elastomeric materials, using a resin coping impression technique with individual shells. A master cast made of stainless steel with fixed prosthesis characteristics with two prepared abutment teeth was used to obtain the impressions. References points (A, B, C, D, E and F) were recorded on the occlusal and buccal surfaces of abutments to register the distances. The impressions were obtained using the following materials: polyether, mercaptan-polysulfide, addition silicone, and condensation silicone. The transfer impressions were made with custom trays and an irreversible hydrocolloid material and were poured with type IV gypsum. The distances between identified points in gypsum dies were measured using an optical microscope and the results were statistically analyzed by ANOVA (p < 0.05) and Tukey's test. The mean of the distances were registered as follows: addition silicone (AB = 13.6 µm, CD=15.0 µm, EF = 14.6 µm, GH=15.2 µm), mercaptan-polysulfide (AB = 36.0 µm, CD = 36.0 µm, EF = 39.6 µm, GH = 40.6 µm), polyether (AB = 35.2 µm, CD = 35.6 µm, EF = 39.4 µm, GH = 41.4 µm) and condensation silicone (AB = 69.2 µm, CD = 71.0 µm, EF = 80.6 µm, GH = 81.2 µm). All of the measurements found in gypsum dies were compared to those of a master cast. The results demonstrated that the addition silicone provides the best stability of the compounds tested, followed by polyether, polysulfide and condensation silicone. No statistical differences were obtained between polyether and mercaptan-polysulfide materials.

Kaon and pion femtoscopy at the highest energies available at the BNL Relativistic Heavy Ion Collider (RHIC) in a hydrokinetic model

The hydrokinetic approach, that incorporates hydrodynamic expansion of the systems formed in A+A collisions and their dynamical decoupling, is applied to restore the initial conditions and space-time picture of the matter evolution in central Au+Au collisions at the top RHIC energy. The analysis is based on the detailed reproduction of the pion and kaon momentum spectra and femtoscopic data in whole interval of the transverse momenta studied by both STAR and PHENIX collaborations. The fitting procedure utilizes the two parameters: the maximal energy density at supposed thermalization time 1 fm/c and the strength of the pre-thermal flows developed to this time. The quark-gluon plasma and hadronic gas is supposed to be in complete local equilibrium above the chemical freeze-out temperature $T_{ch}$ = 165 MeV with the equation of states (EoS) at high temperatures as in the lattice QCD. Below $T_{ch}$ the EoS in the expanding and gradually decoupling fluid depends on the composition of the hadron-resonance gas at each space-time point and accounts for decays of resonances into the non-equilibrated medium. A good description of the pion and kaon transverse momentum spectra and interferometry radii is reached at both used initial energy density profiles motivated by the Glauber and Color Glass Condensate (CGC) models, however, at different initial energy densities. The discussion as for the approximate pion and kaon $m_T$-scaling for the interferometry radii is based on a comparison of the emission functions for these particles.

The Clinical Microscope and Direct Composite Veneer

This paper presents the advantages and limitations related to the use of a clinical microscope in restorative dentistry, and it demonstrates the aid of magnification during preparation and restoration of a direct composite veneer. Good illumination and visibility is important to adequately viewing the adjacent dental tissues so that the resin composite buildup can mimic natural teeth. The reproduction of details results in a naturally esthetic direct veneer.

A study on the effect on surface detail reproduction of alginate impressions disinfected with sodium hypochlorite and ultraviolet light - An In Vitro study.

To evaluate the surface detail reproduction of dental casts with impressions made using commercially available alginate impression materials after disinfecting with chemical disinfectant sodium hypochlorite and physical means of disinfection using ultraviolet radiation. A stainless steel die was used to make impression according to ADA/ANSI specification No. 18 having 25, 50 and 75 µm lines. Totally 70 impressions were made and divided in to 7 groups. The impressions in the first group were only rinsed with 250 ml of water. The 2nd, 3rd and 4th groups were disinfected by immersing in sodium hypochlorite for 1, 5 and 10 minutes, respectively. Fifth, 6th and 7th group samples were disinfected by placing them in ultraviolet chamber for 6, 12 and 18 minutes, respectively. All the impressions were poured immediately using type III gypsum. The casts were recovered and subjected for evaluation of the 75 µm lines using stereomicroscope. There was no statistically significant change in the surface detail reproduction when disinfected with sodium hypochlorite or ultraviolet radiation. Alginate impressions subjected to immersion disinfection using sodium hypochlorite for 1, 5 and 10 minutes and subjected to ultraviolet disinfection for 6, 12 and 18 minutes exhibited no statistically significant differences for surface detail reproduction compared to control groups.

How mold inserts influence the replication of metallic microparts produced by electroplating into two-component templates

Multi-component injection molding combined with electroplating, the so-called MSG process, represents a promising process chain to replicate metallic microstructures. MSG is the German acronym of ‘Mehrkomponenten-Spritzgiesen und Galvanoformung’, in English ‘Multi-component Injection Molding and Electroplating’. The process is based on the highly accurate reproduction of surface details through injection molding to build a microstructure into a two-component template and electrodeposition of e.g. nickel into this cavity. This electroplated micropart is the replication of the former structure. To study the influence of the mold insert on the accuracy of the molded part and the produced microparts, a test specimen was fabricated and analyzed using a milled mold insert. On the mold insert, three microcoil parts, the components of a microgripper, were micromilled. The effect of the individual process steps on the surface quality and dimensional changes of the final microcoil will be presented. It will also be shown how the quality of the injection molding insert influences the dimensional accuracy of the produced microparts. Finally, potential process improvements will be outlined.

Effects of radio-opacifier addition in dental impression material

The aim of this in vitro study was to determine the effects of barium sulfate addition in two dental impression materials previously proved as radiolucent. An irreversible hydrocolloid (IH) and polyether (PE) were tested for optical density, linear dimension stability and detail reproduction. The optical density data were submitted to Kolmogorov-Smirnov normality test and compared with two-way ANOVA and Tukey (alpha=0.05). The results of optical density (pixel) were: IH control 45.24 f (+/-7.6), PE control 54.93 e (+/-4.45), PE 5Wt% 60.43 d (+/-6.27), IH 1Wt% 61.54 cd (+/-5.3), PE 1Wt% 66.9 bc (+/-5.05), IH 5Wt% 67.17 b (+/-6.01), PE 10Wt% 84.55 a (+/-5.14), IH 10Wt% 85.33 a (+/-5.53). On detail reproduction, polyether control was able to copy the 6 microm line. Adding 1 or 5Wt% of barium sulfate have not change this characteristic. For the irreversible hydrocolloid, the control group was able to copy a line with 14 microm, however, adding 1Wt% barium sulfate, the capability decreased to 22 microm. Adding barium sulfate in the polyether promoted an increase in between the copied lines, for the control, the average distance was 931.6 microm, 936 microm to 1Wt% and 954.5 microm to 5 Wt%. For the IH, the control presented 975 microm in comparison to 987.25 microm for 1 Wt% samples. The addition of barium sulfate was capable of increasing significantly the optical density of tested material, have changed the linear dimension stability, however, have not interfered in detail reproduction only for PE.

Influence of opacifiers on dimensional stability and detail reproduction of maxillofacial silicone elastomer

BackgroundWe evaluated the influence of chemical disinfection and accelerated aging on the dimensional stability and detail reproduction of a silicone elastomer containing one of two opacifiers.MethodsA total of 90 samples were fabricated from Silastic MDX 4-4210 silicone and divided into groups (n = 10) according to opacifier content (barium sulfate or titanium dioxide) and disinfectant solution (neutral soap, Efferdent, or 4% chlorhexidine). The specimens were disinfected 3 times per week during 60 days and then subjected to accelerated aging for 1008 hours. Dimensional stability and detail reproduction tests were performed after specimens' fabrication (baseline), chemical disinfection and periodically during accelerated aging (252, 504, and 1008 hours). The results were analyzed using 3-way repeated-measures ANOVA and the Tukey HSD test (α = 0.05).ResultsAll groups exhibited dimensional changes over time. The opacifier (p = .314), period (p < .0001) and their interactions (p = .0041) affected the dimensional stability of the silicone. Statistical significant dimensional differences occurred between groups with (0.071) and without opacifiers (0.053). Accelerated aging influenced the dimensional stability of the samples. All groups scored 2 in the detail reproduction tests, which represents the fully reproducing of three test grooves with accurate angles.ConclusionsIncorporation of opacifiers alters the dimensional stability of silicones used in facial prosthetics, but seems to have no influence on detail reproduction. Accelerated aging is responsible for most of the dimensional changes in Silastic MDX4 4210, but all dimensional changes measured in this study remained within the limits of stability necessary for this application.

Print Quality Comparison Between Kodak Prosper and Offset Lithography

Kodak Prosper Imprinting System with stream inkjet technology targets high volume direct mail market and customized products with print quality close to offset output. This study compared the print quality of a Kodak Prosper press and a Heidelberg Speedmaster CD 74 press. The parameters studied were solid/tone uniformity, tone reproduction, rub resistance, and detail reproduction. The lithography samples included typical screen ruling settings of 133 lpi and 150 lpi for photograph quality comparison. The samples printed were presented to and evaluated by observers with or without graphic arts experience. The visual comparison and quantitative data were presented. The results showed that Kodak Prosper press has decent print quality with good color appearance. The detail reproduction quality is not comparable with lithography quality.

Surface reproduction of elastomeric materials: viscosity and groove shape effects

Objective: To evaluate the effect of viscosity and type of grooves on surface detail reproduction of elastomeric impression materials. Methods: Express putty/light-, Impregum medium- and heavy/light-bodied and Aquasil medium- and putty/light-bodied elastomeric impression materials were chosen for this study. Five impressions were made using a cylindrical aluminum reference block with U- and V- shaped grooves and to produce 35 master dies. Each master die was immersed in distilled water at 370 C for 5 minutes prior to the impression making on moist surfaces. Surface topography of the dies and impressions were captured using Alicona Imaging System. The mean difference in depth between the master dies and its corresponding impressions were analysed using two-way ANOVA, p=.01. Results: The lowest mean difference in depth for U- and V-shaped grooves was obtained from the Express putty/light group. The highest mean difference in depth for U- and V-shaped grooves was obtained from Impregum medium, Aquasil medium, Impregumâ??Â? heavy/light and Impregum heavy/light groups respectively. Two-way ANOVA indicated that there was a significant difference in the effect of materials (p < .01) and grooves (p < .01). Conclusion: Express putty/light-bodied elastomeric material produced the best surface detail, and U-shaped groove showed better surface detail reproduction than V-shaped groove.

Accuracy of high‐resolution photogrammetric measurements of gullies with contrasting morphology

AbstractField techniques allow accurate direct measurements on gully geometry, even in three‐dimensional (3D) coordinates. Accuracy and detail reproduction is limited mainly by experimental setup and density of measurements, and less so by the precision of the measuring equipment. In contrast, remote‐sensing techniques permit the coverage of large study areas with a minimum of time and effort. However, the indirect measurements from imagery are known to depend on factors like image resolution, quality of ground control, vegetation cover and image evaluation technique, which strongly influence the measurement accuracy. The objective of the present study was to investigate to what extent the accuracy of 3D gully measurement using photogrammetric techniques depends on gully morphology. At a study site in the Bardenas Reales (Navarre, Spain), field measurements of cross‐sections were taken for five gullies with contrasting morphology and dimensions and used as reference data for analysing the errors associated with a corresponding dataset obtained using small‐format aerial photogrammetry whose pixel size on the ground is 16 mm.Results show that volumetric gully measurements by means of photogrammetric techniques are strongly affected by the gully morphology; in particular by its width/depth (W/D) ratio, because of the increasing sun‐shadowing and sight‐shadowing effects associated with narrower gullies. Only wide, shallow gullies are little affected by this problem. For gullies of an intermediate typology (W/D between 0·5 and 2·5), the accuracy of photogrammetric measurements will much depend on the time of day and the period of the year when the photographs are taken, and narrow/deep gullies (W/D &lt; 0·5) will be likely to be highly inaccurate at any time. Although this study was conducted with a large measurement scale for small (mostly ephemeral) gullies, the W/D ratios judged challenging for photogrammetric analysis in this study are also common for larger‐sized gullies of the (permanent) bank gully type. Copyright © 2009 John Wiley &amp; Sons, Ltd.

Effect of Incorporation of Disinfectant Solutions on Setting Time, Linear Dimensional Stability, and Detail Reproduction in Dental Stone Casts

The aim of this paper was to analyze the influence of incorporation of disinfectants during the cast die stone-setting time. Setting time, linear dimensional stability, and reproduction details on casts were measured. Die stone type IV specimens with disinfection solutions (sodium hypochlorite 1%, glutaraldehyde 2%, chlorhexidine 2%) were incorporated in two concentrations (50%, 100%). The detail reproduction, dimensional stability, and setting time were tested in accordance with ADA recommendations. Disinfecting solutions promoted an increase in setting time compared to control; sodium hypochlorite was responsible for the highest setting time. The addition of undiluted sodium hypochlorite 1.0% led to contraction during setting, but the groups with 50% diluted sodium hypochlorite 1.0% and undiluted chlorhexidine 2.0% resulted in intermediate values compared to the other groups, thus matching the control. The others did not demonstrate any effect on expansion. For detail reproduction, it was observed that the control group presented results similar to the others, except those where sodium hypochlorite was added. The addition of sodium hypochlorite in both dilutions significantly altered, negatively, all the evaluated properties. But the addition of glutaraldehyde and chlorhexidine did not promote any significant alterations in the evaluated properties.

Chromophore Structure of Cyanobacterial Phytochrome Cph1 in the Pr State: Reconciling Structural and Spectroscopic Data by QM/MM Calculations

A quantum mechanics (QM)/molecular mechanics (MM) hybrid method was applied to the Pr state of the cyanobacterial phytochrome Cph1 to calculate the Raman spectra of the bound PCB cofactor. Two QM/MM models were derived from the atomic coordinates of the crystal structure. The models differed in the protonation site of His260 in the chromophore-binding pocket such that either the δ-nitrogen (M-HSD) or the ɛ-nitrogen (M-HSE) carried a hydrogen. The optimized structures of the two models display small differences specifically in the orientation of His260 with respect to the PCB cofactor and the hydrogen bond network at the cofactor-binding site. For both models, the calculated Raman spectra of the cofactor reveal a good overall agreement with the experimental resonance Raman (RR) spectra obtained from Cph1 in the crystalline state and in solution, including Cph1 adducts with isotopically labeled PCB. However, a distinctly better reproduction of important details in the experimental spectra is provided by the M-HSD model, which therefore may represent an improved structure of the cofactor site. Thus, QM/MM calculations of chromoproteins may allow for refining crystal structure models in the chromophore-binding pocket guided by the comparison with experimental RR spectra. Analysis of the calculated and experimental spectra also allowed us to identify and assign the modes that sensitively respond to chromophore-protein interactions. The most pronounced effect was noted for the stretching mode of the methine bridge A-B adjacent to the covalent attachment site of PCB. Due a distinct narrowing of the A-B methine bridge bond angle, this mode undergoes a large frequency upshift as compared with the spectrum obtained by QM calculations for the chromophore in vacuo. This protein-induced distortion of the PCB geometry is the main origin of a previous erroneous interpretation of the RR spectra based on QM calculations of the isolated cofactor.

Comparison of the Spatial Landmark Scatter of Various 3D Digitalization Methods

The aim of this study was to compare four different three-dimensional digitalization methods on the basis of the complex anatomical surface of a cleft lip and palate plaster cast, and to ascertain their accuracy when positioning 3D landmarks. A cleft lip and palate plaster cast was digitalized with the SCAN3D photo-optical scanner, the OPTIX 400S laser-optical scanner, the Somatom Sensation 64 computed tomography system and the MicroScribe MLX 3-axis articulated-arm digitizer. First, four examiners appraised by individual visual inspection the surface detail reproduction of the three non-tactile digitalization methods in comparison to the reference plaster cast. The four examiners then localized the landmarks five times at intervals of 2 weeks. This involved simply copying, or spatially tracing, the landmarks from a reference plaster cast to each model digitally reproduced by each digitalization method. Statistical analysis of the landmark distribution specific to each method was performed based on the 3D coordinates of the positioned landmarks. Visual evaluation of surface detail conformity assigned the photo-optical digitalization method an average score of 1.5, the highest subjectively-determined conformity (surpassing computer tomographic and laser-optical methods). The tactile scanning method revealed the lowest degree of 3D landmark scatter, 0.12 mm, and at 1.01 mm the lowest maximum 3D landmark scatter; this was followed by the computer tomographic, photo-optical and laser-optical methods (in that order). This study demonstrates that the landmarks' precision and reproducibility are determined by the complexity of the reference-model surface as well as the digital surface quality and individual ability of each evaluator to capture 3D spatial relationships. The differences in the 3D-landmark scatter values and lowest maximum 3D-landmark scatter between the best and the worst methods showed minor differences. The measurement results in this study reveal that it is not the method's precision but rather the complexity of the object analysis being planned that should determine which method is ultimately employed.

Dimensional Accuracy of an Epoxy Die Material Using Different Polymerization Methods

Shrinkage of resinous die materials during setting reaction limits their acceptance, even though these materials show several advantages compared to stone die materials with respect to strength, abrasion resistance, and detail reproduction. The purpose of this study was to determine if retarding the setting reaction during polymerization and altering the base-to-catalyst ratio, as suggested by previous studies, can be recommended for resinous die materials to reduce the inaccuracy in transferring the spatial position of teeth or implants from the oral cavity to the master cast. A Blue Star Type E epoxy resin die material was tested. A reference triangular metal master die was fabricated. Forty medium-consistency polyether impressions of this model were made. Four groups (S, M, N, P) were compared, and ten dies were fabricated for each group. In the S group, the epoxy resin die material was manipulated according to the manufacturer's instructions; in the other three groups, the epoxy resin die material was manipulated by retarding the setting reaction and by modifying the epoxy resin base/activator ratio. One-way ANOVA revealed significant differences between the four groups of the epoxy resin die material (p < 0.0001). Tukey's multiple comparisons test (p < 0.05) revealed that none of the resin groups was similar to the metal master die for each of the tested dimensions (A, B, and C). For the specific dimension C, however, the P group was statistically closer to the metal master die than the S group. The epoxy resin die material tested in this research did not improve its dimensional accuracy following retarding polymerization or modifying the epoxy resin base/activator ratio. The epoxy resin material exhibited higher contraction variability across all tested groups. This shrinkage can significantly affect the dimension of the master cast.

Physical properties of morphological units on Comet 9P/Tempel 1 derived from near-IR Deep Impact spectra

In this paper we analyze near-infrared thermal emission spectra of the spatially resolved nucleus of Comet 9P/Tempel 1 obtained by the NASA spacecraft Deep Impact. Maps of spectral reddening, the product X ′ between the beaming function and directional emissivity, as well as surface temperature are constructed. Thermophysical modeling is used to estimate the degree of small scale surface roughness and thermal inertia by detailed reproduction of the empirical temperature map. Mie and Hapke theories are used in combination with numerically calculated beaming functions to analyze the X ′ map and place constraints on composition and grain size of the surface material. We show that it is absolutely mandatory to include small scale surface roughness in thermophysical modeling of this object, since the resulting self heating is vital for reproducing the measured temperatures. A small scale self heating parameter in the range 0.6 ⩽ ξ ⩽ 0.75 is common, but smoother areas where 0.2 ⩽ ξ ⩽ 0.3 are also found. Contrary to models neglecting small scale surface roughness, we find that the thermal inertia of Comet 9P/Tempel 1 generally is high (1000–3000 J m −2 K −1 s −1/2), although it may be substantially lower (40–380 J m −2 K −1 s −1/2) in specific areas. We obtain a disk-averaged reddening of 3.5% kÅ −1, with statistically significant local variations around that value on a ± 1.0 % kÅ − 1 level. Vast regions appear covered by small (∼0.1 μm) highly absorbing grains such as carbon or iron-rich silicates. Other regions appear dominated by somewhat larger (∼0.5 μm) and/or less absorbing grains such as troilite or magnesium-rich silicates. Surface variations in reddening, roughness, thermal inertia, composition and/or grain size are moderately to strongly correlated to the locations of morphological units on the surface. The existence of morphological units with differing physical properties may be primordial, hence reflecting a diversity in the building block cometesimals, or resulting from evolutionary processes.

The Effects of Disinfectants on Dimensional Accuracy and Surface Quality of Impression Materials and Gypsum Casts

BackgroundThe study aimed to evaluating the effect of disinfecting impression materials on the dimensional accuracy and surface quality of the resulting casts.MethodsImpressions of a steel die constructed according to ANSI/ADA specification No.18 were made with each of alginate, addition cured silicone, condensation cured silicone and zinc oxide eugenol paste, and disinfected consequently by each of 0.2% chlorhexidine gluconate, 1% sodium hypochlorite, 2% gluteraldehyde for 5 minutes, and 0.5% sodium hypochlorite for 10 minutes. Dimensions of the disinfected impressions and their resultant casts were measured using a computerized digital caliper, and the dimensional changes were calculated. Reproduction of detail and surface quality of the resultant casts were assessed by grading casts surfaces according to a specific scoring system.ResultsThe 0.5% sodium hypochlorite was found to produce the least dimensional changes in all the impression materials. Corsodyl produced the maximum changes in both alginate and zinc-oxide eugenol while addition-cured silicon was most affected by Gluteraldehyde and condensation-cured silicon was most affected by Hexana. The dimensional changes, however, were minimal and clinically insignificant. Addition-cured silicon showed the best surface quality and dimensional stability followed by condensation-cured silicon. Alginate and zinc-oxide eugenol had poorer surface quality and were affected to a higher extent by the disinfection procedures.ConclusionsThe results were comparable with the standard specifications for dimensional stability. Recommendations were made for the use of 10 minutes immersion in 0.5% sodium hypochlorite as the most appropriate disinfection protocol to the investigated impression materials.KeywordsDisinfectants; Gypsum casts; Impressions; Alginate; Addition-cured silicone; Sodium hypochlorite