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Filler particles like uhm in English or ähm in German show subtle language-specific differences and their variation in form is related to socio-linguistic variables like gender. The use of fillers in a second language has been shown to differ from monolinguals' filler particle use in both frequency and form in different language contexts. This study investigates the language-specific use of filler particles by bilingual heritage speakers in both their languages, looking at the dominant majority language in the society and their minority heritage language spoken at home. This is done based on heritage Russian and German data and majority German and English data from the RUEG corpus. Language-specific fillers were extracted from the corpus and analyzed for their occurrence and segmental form. The frequency analysis suggests an influence of bilingualism, age group, and formality of the situation on the filler frequency across all languages. The number of filler particles is higher in formal, older, and bilingual speech. The form analysis reveals an effect of language and gender on the type of filler particle. The vocalic-nasal filler particles (e.g., uhm) are more frequently found in German and English and in female speech of these languages. Heritage speakers of Russian in contact with German and English show higher use of vocalic-nasal forms also in their Russian while producing similar gender related patterns to monolingual speakers in both their languages. The higher frequency of filler particles in formal situations, older speakers and in bilingual speech, is discussed related to cognitive load which is assumed to be higher in these contexts while speech style which differs between situations and social groups is also considered as explanation. The higher use of vocalic-nasal filler particles in German and English suggests language specific filler particle preferences also related to the socio-linguistic variable gender in these languages. The results from heritage speakers suggest and influence on filler particle form in their heritage language, while also revealing socio-linguistic usage patterns related to gender which are produced by heritage speakers similarly to monolinguals in their respective language. [ABSTRACT FROM AUTHOR]

Filler particles like uhm in English or ähm in German show subtle language-specific differences and their variation in form is related to socio-linguistic variables like gender. The use of fillers in a second language has been shown to differ from monolinguals' filler particle use in both frequency and form in different language contexts. This study investigates the language-specific use of filler particles by bilingual heritage speakers in both their languages, looking at the dominant majority language in the society and their minority heritage language spoken at home. This is done based on heritage Russian and German data and majority German and English data from the RUEG corpus. Language-specific fillers were extracted from the corpus and analyzed for their occurrence and segmental form. The frequency analysis suggests an influence of bilingualism, age group, and formality of the situation on the filler frequency across all languages. The number of filler particles is higher in formal, older, and bilingual speech. The form analysis reveals an effect of language and gender on the type of filler particle. The vocalic-nasal filler particles (e.g., uhm) are more frequently found in German and English and in female speech of these languages. Heritage speakers of Russian in contact with German and English show higher use of vocalic-nasal forms also in their Russian while producing similar gender related patterns to monolingual speakers in both their languages. The higher frequency of filler particles in formal situations, older speakers and in bilingual speech, is discussed related to cognitive load which is assumed to be higher in these contexts while speech style which differs between situations and social groups is also considered as explanation. The higher use of vocalic-nasal filler particles in German and English suggests language specific filler particle preferences also related to the socio-linguistic variable gender in these languages. The results from heritage speakers suggest and influence on filler particle form in their heritage language, while also revealing socio-linguistic usage patterns related to gender which are produced by heritage speakers similarly to monolinguals in their respective language.

Vibration is used to compact the concrete mixture in the manufacture of ferroconcrete parts without molds in long configurations. The transfer of vibrations from a cylindrical punch to filler particles in a viscous concrete mixture is studied. A mathematical description is developed for the motion of a spherical filler particle in a viscous medium set vibrating by a cylindrical punch, and its mean velocity and path in chaotic motion are determined. The range of velocity and path values for punch vibration with industrial frequencies and amplitudes is established. Mathematical modeling is employed. The possibility of varying the mean velocity and path in a viscous medium by adjusting punch vibration is established for particles of different size. [ABSTRACT FROM AUTHOR]

Soy-based yoghurt alternatives were highly requested by consumers over the last few years. However, their texture does not always fulfil consumers' demands as such yoghurt alternatives are often perceived as too firm or too soft, sandy, or fibrous. In order to improve the texture, fibres, for example, in the form of microgel particles (MGP), can be added to the soy matrix. MGP are expected to interact with soy proteins, creating different microstructures and, thus, different gel properties after fermentation. In this study, pectin-based MGP were added in different sizes and concentrations, and the soy gel properties after fermentation were characterised. It was found that the addition of 1 wt.% MGP influenced neither the flow behaviour nor the tribological/lubrication properties of the soy matrix, regardless of the MGP size. However, at higher MGP concentrations (3 and 5 wt.%), the viscosity and yield stress were reduced, the gel strength and cross-linking density decreased, and the water-holding capacity was reduced. At 5 wt.%, strong and visible phase separation occurred. Thus, it can be concluded that apple pectin-based MGP serve as inactive fillers in fermented soy protein matrices. They can, therefore, be used to weaken the gel matrix purposely to create novel microstructures. [ABSTRACT FROM AUTHOR]

In this study, we investigate the use of the filler particles (FPs) uh, um, hm, as well as glottal FPs and tongue clicks of 100 male native German speakers in a corpus of spontaneous speech. For this purpose, the frequency distribution, FP duration, duration of pauses surrounding FPs, voice quality of FPs, and their vowel quality are investigated in two conditions, namely, normal speech and Lombard speech. Speaker-specific patterns are investigated on the basis of twelve sample speakers. Our results show that tongue clicks and glottal FPs are as common as typically described FPs, and should be a part of disfluency research. Moreover, the frequency of uh, um, and hm decreases in the Lombard condition while the opposite is found for tongue clicks. Furthermore, along with the usual F1 increase, a considerable reduction in vowel space is found in the Lombard condition for the vowels in uh and um. A high degree of within- and between-speaker variation is found on the individual speaker level. [ABSTRACT FROM AUTHOR]

In this study, an epoxy biocomposite containing areca fiber, nanosilica, and neem oil bio blender was characterized for various technology applications. The research goal was to show how important it is to include nanosilica particles in neem oil while fabricating a biocomposite with epoxy resin. The surface of the nanosilica particle and areca fiber was treated with 3-Aminopropyltriethoxysilane to improve dispersion across a neem-epoxy blended matrix medium. To create the composites, hand layup technique was used and characterization was performed in accordance with the ASTM standards. Nanosilica at a concentrations of 1 and 2 vol% was added to the neem-epoxy composite to enhance its load bearing properties. It was found that by adding nanosilica particle the hardness of composites EAS1 and EAS2 was found to be higher as 8.67%, and 16.33% on compared with EAS designation. Moreover, improved fatigue life cycles of 3680 and 6620 were noted for composite designations EAS1 and EAS2 respectively. These environment-friendly and highly toughened biocomposite materials could be used in food storage containers, medical component carriers, and household appliances manufacturing. [ABSTRACT FROM AUTHOR]

Background: Discoloration of dental composite restoration is a common problem that usually results in refurbishing or replacement or even removal of the restoration. Objective: The purpose of this study was to evaluate the color stability of polished composite resin material with different filler technologies. Methodology: Three composites were studied; Filtek™ Z350 XT (3M, ESPE, St. Paul, USA) [Group-I] that has nano-cluster filler particles, Brilliant EverGlow™ (Coltene/Whaledent® AG, Altstatten, Switzerland) [Group-II] which consists of submicron barium glass fillers and pre-polymerized fillers and Ceram.X® Sphere TEC™ (Dentsply, Konstanz, Germany) [Group-III] with advanced granulated filler technology composite. Twenty standardized composite discs were prepared with each composite resin, and it was polished with Sof-Lex disks (3M, ESPE, St. Paul, USA). The baseline color was then recorded using a spectrophotometer (X-Rite PANTONE® iPro-2, Michigan). Eight samples from each group were then subdivided and immersed into freshly prepared solutions of turmeric, coffee, and four samples into distilled water for a total period of 3 hours/day for 30 days. Following this, the color was again recorded. Statistical analysis: The change in color (ΔE) was calculated, and the data obtained were subjected to Kruskal Wallis and Mann Whitney test. Results: A significant difference was seen between the staining characteristics of Group-III and Group-I (p3.3). Conclusion: Though all composites revealed color changes after their immersion into the staining solutions, the amount of stain varied based on their constituents and filler characteristics.

• Effects of different fillers on the properties of PLA/PBAT composites are reported. • Filler particles improve the compatibility between PLA and PBAT. • Filler particles improve thermal stability of PLA/PBAT composites. • CaCO 3 filled modified PLA/PBAT composites have better performance. Poly(lactic acid)/poly(butylene adipate-co-terephthalate) (PLA/PBAT) composites modified with different filler particles (lignin, CaCO 3 , wollastonite, and talc) were prepared by one-step melt blending and injection molding (referred to as PPL, PPC, PPW, and PPT, respectively). Scanning electron microscopy showed that the filler particles promoted compatibility between PLA and PBAT in the composites. Among them, the PPC composites had fewer defects in the cross-section, and the compatibility between PLA and PBAT was improved, resulting in the best mechanical properties. Thermal analysis revealed that except for talc, the filler particles could improve the thermal stability of PLA/PBAT composites and increase the crystallinity of the composites. [ABSTRACT FROM AUTHOR]

In this study, we investigate the use of the filler particles (FPs) uh, um, hm, as well as glottal FPs and tongue clicks of 100 male native German speakers in a corpus of spontaneous speech. For this purpose, the frequency distribution, FP duration, duration of pauses surrounding FPs, voice quality of FPs, and their vowel quality are investigated in two conditions, namely, normal speech and Lombard speech. Speaker-specific patterns are investigated on the basis of twelve sample speakers. Our results show that tongue clicks and glottal FPs are as common as typically described FPs, and should be a part of disfluency research. Moreover, the frequency of uh, um, and hm decreases in the Lombard condition while the opposite is found for tongue clicks. Furthermore, along with the usual F1 increase, a considerable reduction in vowel space is found in the Lombard condition for the vowels in uh and um. A high degree of within- and between-speaker variation is found on the individual speaker level.

Solid particle erosion of polymer matrix composites filled with naturally available and environment pollutant fillers have not been studied to the same level as for metals or ceramics and is focus of the present study. In this article, review of the research associated with the erosion response of polymer composites is presented. Particulate polymer composites are employed extensively owing to their enhanced specific properties and tribological response. Particulate filler particles such as environmental pollutants and naturally available ones need to be effectively incorporated in utilitarian applications so as to reduce land fill burden issues and other specific problems. Nevertheless, adequate data is not available in review articles on the erosion of fillers that are environment pollutants and thereby an ample amount of research can be carried out in this regard. Erosion behavior of polymer composites in particular has gained a lot of attention among researches in the recent decade. Viability of incorporating various fillers in polymer matrix for erosion resistive applications needs to be assessed so that the potential of these composites can be well understood. Therefore in this study, erosion response of polymer composites reinforced with fillers is reviewed with a focus on input parameters (impact velocity, impingement angle and erodent properties) and material properties (density). [ABSTRACT FROM AUTHOR]

A spectroscopic method for studying the morphology of microsuspensions based on an analysis of the scattering component of electromagnetic radiation passing through a sample (turbid medium) was proposed and made it possible to determine the average size and size distribution of scattering particles. Suspensions of Vaseline oil (VO) filled with mica and BaSO4 of various concentrations were investigated by optical spectroscopy (UV, visible, and IR regions) and by an independent optical microscopy method. The average sizes of scattering particles were determined using these methods. The size distribution curves were constructed for microsuspensions VO/mica and VO/BaSO4 with 4 and 5% filler content, respectively. The average sizes of the filler particles in the two suspensions determined by independent methods practically coincided at 1.7 and 1.1 μm. The spectroscopic method found that the average size of the filler particles increased as their concentration increased because they aggregated. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the radiopacity, bond strength, and micromorphology of experimental filled dental adhesives. Materials and Methods: Five experimental filled dental adhesives with different concentrations of radiopaque barium-borosilicate glass (wt%) [0 (R0), 30 (R30), 40 (R40), 50 (R50), and 60 (R60)] and the commercial adhesive Adper Single Bond 2 were used in this study. Specimens were prepared by dispensing the uncured resin into a mold (5.0 mm x 1.0 mm). Digital radiographs (n = 5) of both 1-mm-thick adhesive specimens and tooth were taken with a CCD sensor. The gray levels of enamel, dentin, and adhesive systems were measured by histogram analysis and compared. Adhesives were applied to flat dentin surfaces of third molars (n = 7). Resin composite buildups were constructed and sectioned to obtain resin-dentin bonded sticks to test immediately or after 6 months of water storage. Three specimens for each tooth were qualitatively analyzed using scanning electron microscopy. Data on bond strength and radiopacity were evaluated by two-way and one-way ANOVA, respectively, and Tukey's test (α = 0.05). Results: All experimental filled dental adhesives showed radiopacity similar to enamel (p > 0.05) and most yielded significant reductions of bond strength over time. However, the R30 produced a radiopaque material without jeopardizing the bonding of the material to the dentin substrate. Conclusions: The addition of 30% barium-borosilicate oxide produced radiopaque adhesives without jeopardizing the bonding to the dental substrate. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the radiopacity, ultimate tensile strength (UTS), microhardness (KHN), degree of conversion (DC), water sorption (WS) and solubility (SL) of experimental adhesives. Materials and Methods: Five experimental adhesives with different concentrations of barium-borosilicate oxide microfillers [0% (R0), 30% (R30), 40% (R40), 50% (R50), 60% (R60)] were formulated based on the adhesive system Ambar (FGM). The adhesive Adper Single Bond 2 (SB, 3M ESPE) was used as commercial reference. For the radiopacity (n = 5), KHN (n = 5), WS (n = 10), and SL (n = 10) tests, adhesive disks were constructed (5.0 mm in diameter and 1.0 mm thick), while for UTS (n = 5), hourglass-shaped specimens with a cross-sectional area of 0.8 mm² were used. The FTIR spectra of unpolymerized and polymerized adhesives were used to determine the DC. Data were submitted to a one-way ANOVA and Tukey's test (α = 0.05). Results: All experimental adhesives showed radiopacity similar to enamel, except those of R0 and SB. Filler addition did not jeopardize the UTS, KHN, or WS of the filled adhesives in comparison with the unfilled version. Except for R40, filler addition reduced the SL. The filled adhesives showed lower DC when compared with R0, but the DC was similar or higher when compared with SB. Conclusions: The addition of barium-borosilicate glass up to 50% did not jeopardize the mechanical properties of the adhesive layer and seems to reduce its solubility. [ABSTRACT FROM AUTHOR]

Aging in speech production is a multidimensional process. Biological, cognitive, social, and communicative factors can change over time, stay relatively stable, or may even compensate for each other. In this longitudinal work, we focus on stability and change at the laryngeal and supralaryngeal levels in the discourse particle euh produced by 10 older French-speaking females at two times, 10 years apart. Recognizing the multiple discourse roles of euh, we divided out occurrences according to utterance position. We quantified the frequency of euh, and evaluated acoustic changes in formants, fundamental frequency, and voice quality across time and utterance position. Results showed that euh frequency was stable with age. The only acoustic measure that revealed an age effect was harmonics-to-noise ratio, showing less noise at older ages. Other measures mostly varied with utterance position, sometimes in interaction with age. Some voice quality changes could reflect laryngeal adjustments that provide for airflow conservation utterance-finally. The data suggest that aging effects may be evident in some prosodic positions (e.g., utterance-final position), but not others (utterance-initial position). Thus, it is essential to consider the interactions among these factors in future work and not assume that vocal aging is evident throughout the signal.

The purpose of this study was to evaluate the surface roughness (Ra), and the morphology and composition of filler particles of different composites submitted to toothbrushing and water storage. Disc‐shaped specimens (15 mm × 2 mm) were made from five composites: two conventional (Z100™, and Filtek™ Supreme Ultra Universal, 3M), one "quick‐cure" (Estelite ∑ Quick, Tokuyama), one fluoride‐releasing (Beautiful II, Shofu), and one self‐adhering (Vertise Flow, Kerr) composite. Samples were finished/polished using aluminum oxide discs (Sof‐Lex, 3M), and their surfaces were analyzed by profilometry (n = 5) and scanning electron microscopy (SEM; n = 3) at 1 week and after 30,000 toothbrushing cycles and 6‐month water storage. Ra data were analyzed by two‐way analysis of variance and Tukey's test (α = 0.05). Filler particles morphology and composition were analyzed by SEM and X‐ray dispersive energy spectroscopy, respectively. Finishing/polishing resulted in similar Ra for all the composites, while toothbrushing and water storage increased the Ra of all the tested materials, also changing their surface morphology. Beautifil II and Vertise Flow presented the highest Ra after toothbrushing and water storage. Filler particles were mainly composed of silicon, zirconium, aluminum, barium, and ytterbium. Size and morphology of fillers, and composition of the tested composites influenced their Ra when samples were submitted to toothbrushing and water storage. [ABSTRACT FROM AUTHOR]

Abstract In this article, we propose a computational heat conduction model to estimate the thermal conductivity of composites with high volume fraction of filler particles distributed randomly in the base matrix. Most of the presently available models used for estimating the thermal conductivity of the composite materials fail after a certain volume fraction of the filler due to the effect of percolation i.e. the formation of 'heat transfer paths' formed by the filler particles within the composite. The proposed model accounts for this percolation effect and estimates the thermal conductivity of a composite material with Aluminium as the filler in the Epoxy matrix. The algorithm for the proposed model is developed using MATLAB program and is used to obtain the thermal conductivity of the composite by entering the specifications of the parent components of the composite. The proposed model is able to predict the thermal conductivity of composites of high volume fraction of filler over the temperature range of 50 K–300 K and the results obtained are in good agreement with the experimental data. Highlights • Percolation theory based analytical heat conduction model has been developed. • Model is applicable to predict the thermal conductivity of binary composites with high volume fraction (>30%) of fillers. • The model predicts the thermal conductivity values at all temperatures from 50 K to 300 K. • The thermal conductivity values predicted by the model matches well with our experimental results and published data. [ABSTRACT FROM AUTHOR]

Abstract Applications such as filtration require not only control over the pore structure but also over properties like surface characteristics and mechanical strength. The addition of filler particles to solution based freeze casting of preceramic polymers combines the flexibilities of freeze casting and preceramic polymers. Alumina platelets, silica spheres and preceramic filler particles with different compositions were frozen in solution based freeze casting of preceramic polymers with cyclohexane as solvent. Methyl- and methyl-phenyl polysiloxanes as well as (3-aminopropyl)triethoxysilane were used as precursors and cross-linking agent, respectively. The compressive strength increases by factors of up to 1.9 (25 vol% preceramic filler) due to enhanced isotropy of the dendritic pore structure. At lower concentrations (1.7 vol%), alumina platelets are more effective in strengthening than spherical particles. In dependence on the composition of the preceramic filler, BET surface area and the ratio of vapor uptake between water and heptane change by factors of up to 1.19 and 16, respectively. Calculations according to a linear rule of mixture fit very well with the experimental data. In summary, the versatile approach to add differing filler particles to solution based freeze casting allows for tailoring the pore structure as well as surface characteristics of macroporous monolithic samples. Graphical abstract Unlabelled Image Highlights • Addition of preceramic and ceramic fillers overcomes limitations of solution based freeze-casting of polysiloxanes. • Enhanced isotropy of pore structure increases the compressive strength by factors of up to 1.9. • Different chemical compositions of filler particles allow for altering the BET surface area from 276.4-535.2 m2g-1. • Ratio of water to heptane uptake as a measure of hydrophilicity can be adjusted in a range from 0.13-2.86. • Linear rule of mixture precisely predicts hydrophilicity and BET surface area and allows design of properties. [ABSTRACT FROM AUTHOR]

Polymer matrix composites (PMCs) are extensively known for their higher strength and stiffness at lower weight compared to traditional materials. They are extensively used in numerous engineering applications. Utilization of these materials had been extended to novel areas where it is essential to study their tribological performance. Several research works reported the tribological performance of polymer composites. The aim of the review is to provide broad information on erosion behaviour of polymeric composites. Attention is paid towards the effect of test parameters i.e. impact velocity, erodent characteristics, impingement angle on the erosion wear rate and their failure mechanisms were discussed. Inclusion of various fillers in to polymeric composites enriched the erosion resistance property that attracted the researchers to find out their application. However limited literature were available on the erosion behaviour of particle filled composites. Hence, another objective is to review available literature on the erosion response of filled composites.

In recent decade, polymer matrix composites were extensively used in various engineering applications owing to their advanced properties over conventional materials and enhanced performance. This motivated the researchers to generate an extensive study and research work on polymer composites. In recent studies, the erosion properties of the polymer composite attract increasing attention among researchers. The potential enhancement in the erosion resistance property of filled composites tempted the researchers to find the feasibility of using various filler materials in polymer matrix for specific erosion resistance applications. However, only limited numbers of literature are available concerning the tribological performance of the filled composite. Hence in this study, an objective was set to review the various literature that explain the erosion characteristics of filled composites. [ABSTRACT FROM AUTHOR]

This study investigated the influence of model filler particles (glass beads) on the microstructure and rheological properties of Mozzarella cheese. Model Mozzarella cheese composites with increasing volume fractions of glass beads of various sizes and surface properties were processed in a Rapid Visco Analyser (RVA). Confocal laser scanning microscope images showed that all the hard spheres were dispersed in the protein phase, rather than in the fat phase. Dynamic oscillatory rheology revealed that the volume fraction of the glass beads had a major influence on the complex modulus ( G*) of the cheese composites, whereas the size and the coating of the glass beads had no influence. However, the zero shear viscosity ( η ), measured using the creep-compliance test, was affected by both the size and the volume fraction of the glass beads. This indicated that there were some interactions between the glass beads and the cheese matrix. Filler-matrix interactions played a major role in the fracture properties of the cheese composites. The fracture stress ( σ ) was highly dependent on the coating and the size of the glass beads. Simple equations for filled gels from the literature fitted well with the experimental results and could be successfully applied for future predictions. According to this study, the transfer of knowledge from filled polymer composites to model cheese appears relevant. This can provide a good basis for designing new dairy product structures. [ABSTRACT FROM AUTHOR]

Introduction: Filler size affects how the material is coated and finished, while filler stacking affects how strong the material is, how flexible it is, how resistant it is to wear, and how much it shrinks when it polymerizes. The purpose of this research was to compare micro-hybrid, nano-composite, and bulk-fill composites with respect to their compressive strength, diametric tensile strength, and flexural strength., Materials and Methods: To organize the samples according to International Organization for Standardization (ISO) 4049 and American Dental Association (ADA) detail number 27, we used a custom-made Teflon mold. A total of 45 samples were used, with 15 samples in each group. The sample was mounted on a state-of-the-art general testing machine to determine its compressive strength and polar rigidity. The 3-point bowing test was used to determine flexural strength. A one-way analysis of variance (ANOVA) was used for quantitative analysis, followed by a post hoc test with a significance level of P < 0.05., Results: The Tetric N Ceram Bulk Fill, the Filtek Z350 XT nanocomposite, and the T-Econom micro-hybrid composite all had different levels of flexural and compressive strength. This difference was statistically significant. Nanocomposites have superior compressive and flexural strengths to their counterparts analyzed in the present study., Conclusion: Nano-composite combines the properties of being strong and looking good. It can be used in both front and back restorations that need to be strong enough to withstand the forces of chewing., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2023, Nagrale et al.)

Objective The aim of this study was to evaluate whether the mechanical properties of the modern dental composites can be improved by using tetrapodal ZnO particles as fillers in a Bis-GMA/TEGDMA matrix. Another aim was to test whether the mechanical properties of the composite are influenced by functionalization of the ZnO particles with lauric acid to achieve antibacterial activity. Methods Different filler materials and particle shapes (spherical zirconia, spherical zinc oxide, tetrapodal zinc oxide) were used to produce Bis-GMA/TEGDMA based composites with a filler content of 40 wt.-% and 60 wt.-%, respectively. In addition, functionalization with lauric acid was investigated. For the biaxial flexural strength testing 104 test disks ( N = 8) with a diameter of 15 mm and a thickness of 1.5 mm were produced. Results Functionalization with lauric acid resulted in a decrease in biaxial flexural strength for all filler materials. The biaxial flexural strength decreased when using a higher filler content with spherical particles but increased when using tetrapodal zinc oxide particles. Significance A higher durability of the composites using tetrapodal zinc oxide particles. An antibacterial functionalization with lauric acid cannot be recommended as the mechanical stability of the composite will be reduced. [ABSTRACT FROM AUTHOR]

The effect of nano-fillers (carbon carbon nanotubes) on thermophysical properties of epoxy composites is investigated. The curve showing the dependence between the heat resistance of epoxy composite and the content of nanoparticles demonstrates the optimal content of carbon carbon nanotubes, indicating the improved performance characteristics of the material with the above content of carbon carbon nanotubes. To analyze the processes of structure formation and the behavior of composites under the influence of a thermal field, the thermal coefficient of linear expansion of materials is investigated. It is established that the thermal linear expansion coefficient of materials increases with an increase in temperature within different temperature areas under study. Additionally, the thermogravimetric (TGA) and differential thermal (DTA) analysis of the materials were conducted for the investigation of nanocomposites under elevated temperatures. The maximum values of endothermic and exothermic effects in composites depending on their filling are found. [ABSTRACT FROM AUTHOR]

Purpose To evaluate the effect of glass fiber/filler particles proportion on flexural strength and diametral tensile strength of an experimental fiber-reinforced composite. Methods Four experimental groups ( N = 10) were created using an experimental short fiber-reinforced composite, having as a factor under study the glass fiber (F) and filler particle (P) proportion: F22.5/P55 with 22.5 wt% of fiber and 55 wt% of filler particles; F25/P52.5 with 25 wt% of fiber and 52.5 wt% of filler particles; F27.5/P50 with 27.5 wt% of fiber and 50 wt% of filler particles; F30/P47.5 with 30 wt% of fiber and 47.5 wt% of filler particles. The experimental composite was made up by a methacrylate-based resin (50% Bis-GMA and 50% TEGDMA). Specimens were prepared for Flexural Strength (FS) (25 mm × 2 mm × 2 mm) and for Diametral Tensile Strength (DTS) (3 × 6 Ø mm) and tested at 0.5 mm/min in a universal testing machine. Results The results (in MPa) showed significance (different superscript letters mean statistical significant difference) for FS ( p < 0.009) and DTS ( p < 0.001) – FS results: F22.5/P55: 217.24 ± 20.64 B ; F25/P52.5: 245.77 ± 26.80 AB ; F27.5/P50: 246.88 ± 32.28 AB ; F30/P47.5: 259.91 ± 26.01 A . DTS results: F22.5/P55: 21.82 ± 4.42 B ; F25/P52.5: 22.00 ± 7.40 B ; F27.5/P50: 18.63 ± 4.41 B ; F30/P47.5: 31.05 ± 2.97 A . In SEM analysis, areas without fiber reinforcement demonstrated to be more prone to the presence of bubbles and crack development. The group F30/P47.5 showed areas with a great quantity of fibers without empty spaces for crack propagation. Conclusion Increasing fiber content results in higher flexural and diametral tensile strength of an experimental composite reinforced with glass fibers. [ABSTRACT FROM AUTHOR]

Objective: The aim of this study was to characterize the chemical elements and morphology of filler particles of conventional and low-shrinkage composite resins. The main components were identified by means of energy-dispersive X-ray spectroscopy (EDX) microanalysis; whereas filler particles were analyzed morphologically by scanning electron microscopy (SEM). Methods: Four composite resins were studied: two conventional ones (Heliomolar and Tetric N-Ceram, Ivoclar VivadentTM) and two low-shrinkage ones (Aelite LS, BiscoTN; and Filtek Silorane, 3M ESPETM). The material (five samples of each resin) was immersed in organic solvents to eliminate the organic phase and was assessed by SEM and EDX. Results: Although EDX measurements showed a high content of silicon in all samples, there were differences in the elemental composition. Aelite LS composite resin contained spherical and irregular particles, whereas the other composites contained only irregularly shaped filler particles. Heliomolar composite resin had the highest particle size. Conclusion: All composite resins contained silicon, but the other components were also found. Resins differed in terms of filler particle size and morphology. [ABSTRACT FROM AUTHOR]

On the basis of inclusion complex formation of starch with small guest molecules, the concept of filler modification for papermaking by calcium-ion-induced deposition of starch/rosin complexes in the presence of filer particles was demonstrated. The rosin amount of 3% (on the basis of the dry weight of starch) induced effective starch deposition. Due to the cellulose-bondable nature of starch/rosin complexes, filler modification resulted in improved interaction of precipitated calcium carbonate particles with cellulosic fibers, leading to reduced negative impact of filler addition on paper strength. The efficiency of alkyl ketene dimer emulsion as an internal sizing agent for cellulosic paper was also improved as a result of filler modification. The concept demonstrated in this study may provide a useful alternative to the improvement of the use of mineral fillers in the paper industry. [ABSTRACT FROM AUTHOR]

Mixed matrix membranes (MMMs), as a new membrane generation, have been an attractive subject of the worldwide academic and industrial studies accomplished by many researchers. Although many different models have been adapted and/or developed for MMMs' permeability prediction, almost of them neglect the so-called impermeable filler particles' permeabilities, e.g. Pd = 0. In the current study, a new theoretical model is developed to predict MMMs performance considering a surface flux (or permeability) for the so-called impermeable filler particles. Due to the adsorption of the penetrants on the filler particles' surface, there is surface flux on the filler particles. In order to develop a proper model, the ideal MMM structure is divided into three regions: polymer matrix, coating and filler surface regions. Model equations for each region was developed and then the current and the employed predictive models prediction results were compared with those of experimentally measured data. Very well agreement with the current model result with the experimental data was found (e.g. AAREs were reduced from 52.65 to 31.74%, from 51.12 to 28.22% and from 55.33 to 31.50% for the Maxwell, the Bruggeman and the Pal models, respectively in the current proposed model). [ABSTRACT FROM AUTHOR]

ABSTRACT This study investigated the effect of the filler particle size (micron or submicron) of experimental resin cements on the microtensile bond strength to a glass-ceramic pretreated with hydrofluoric acid (HFA) etching or alumina airborne-particle abrasion (AA). Cements were obtained from a Bis-GMA/TEGDMA mixture filled with 60 mass% micron-sized (1 ± 0.2 µm) or submicron-sized (180 ± 30 µm) Ba-Si-Al glass particles. Ceramic blocks (PM9; VITA) were treated with 10% HFA for 60 s or AA for 15 s. Silane and adhesive were applied. Ceramic blocks were bonded to resin composite blocks (Z250; 3M ESPE) using one of the cements. Bonded specimens were sectioned into beams ( n = 20/group) and subjected to microtensile bond strength tests. Data were analyzed using ANOVA and Student-Newman-Keuls' tests (5%). Failure modes were classified under magnification. Morphologies of the treated ceramic surfaces and bonded interfaces were evaluated by scanning electron microscopy. The HFA-submicron group had lower bond strengths than the other groups. All AA-submicron specimens debonded prematurely. Mixed failures were predominant for HFA groups, whereas interfacial failures predominated for AA groups. SEM revealed a honeycomb-like aspect in the HFA-treated ceramic, whereas the AA-treated groups showed an irregular retentive pattern. Continuity of cement infiltration along the bonded interface was more uniform for HFA-treated compared to AA-treated specimens. Cracks toward the bulk of the ceramic were observed in AA-treated specimens. Particle size significantly influenced the ceramic bond strength, whereas surface treatment had a minor effect. Microsc. Res. Tech. 77:363-367, 2014. © 2014 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Enhanced electrical properties of insulating materials containing nanoscale filler particles (nanocomposites) are attributed to an interfacial area that is formed between the polymer matrix of the base material and the filler particles. So far the interfacial area could not be made visible. The two materials investigated in this study are based on the same silicone matrix material and either contain filler particles of the type F1 or filler particles of the type F2, both of them having nearly the same primary particle diameter. Differences in the electrical properties of the two materials are interpreted by an interfacial area that is larger around filler particles of the type F1 than around filler particles of the type F2. To gain an insight into the interfacial area the two materials were investigated by Atomic Force Microscopy (AFM) and Electric Force Microscopy (EFM). In the EFM images the both types of filler particles appear larger in the composite material than they do when they are not embedded in the composite material. This difference is explained by an interfacial area that surrounds both types of filler particles if they are embedded in the base material. As the particles of the type F1 appear significantly larger than the particles of the type F2 in the EFM images it can be concluded that the interfacial area around the filler particles of the type F1 is larger than the interfacial area around the filler particles of the type F2. By the combination of electrical measurements, their interpretation with models and AFM and EFM measurements the existence of the interfacial area in the investigated nanocomposites could be proven. The measurement results also give a hint on the nature of the interfacial area which could either be charge carriers forming an electrical double layer around the nanoparticles or a change in morphology of the polymer surrounding the particles by polymer-filler interaction resulting in a change of permittivity of the surrounding polymer region. Most notably the interfacial area could be made visible by EFM measurements. [ABSTRACT FROM AUTHOR]

Abstract: Objectives: A model resin composite containing a novel monomodal inorganic filler system based on submicron-sized Ba–Si–Al glass particles (NanoFine NF180; Schott) was formulated and compared with an experimental composite containing micron-sized particles (UltraFine UF1.0; Schott). Methods: The filler particles were characterized using X-ray microanalysis and granulometry, while the composites were characterized in terms of filler–resin morphology, radiopacity, degree of C C conversion, hardness, flexural strength/modulus, work-of-fracture, surface roughness and gloss (before and after simulated toothbrushing abrasion), and bulk compressive creep. The composites were formulated from the same photoactivated dimethacrylate co-monomer, incorporating mass fractions of 75% micron- and 78% submicron-sized particles. Quantitative data were analyzed at a significance level of p <0.05. Results: Both filler systems exhibited a narrow grain size range (175±30 and 1000±200nm), with differences restricted to the size and specific area of the particles. The composites were similar in radiopacity, flexural strength, work-of-fracture, and creep. The submicron composite was harder but had lower flexural modulus and C C conversion. No significant differences in roughness were observed before brushing, although the submicron composite had higher gloss. Brushing increased roughness and decreased gloss on both materials, but the submicron composite retained higher gloss after brushing. Significance: The monomodal submicron glass filler system demonstrated potential for use in restorative dental composites, particularly due to improved esthetic properties. [Copyright &y& Elsevier]

Abstract: Objectives: The purpose of this study was to compare the mechanical and rheological properties of resin-based pit and fissure sealants to flowable resin composites in order to define clinical indications based on these properties. Methods: Eight flowable resin composites (Admira Flow, Filtek Supreme XT Flow, FlowLine, Grandio Flow, Point-4 Flowable, Premise Flowable, Revolution Formula 2, X-Flow) and four resin-based pit and fissure sealants (Clinpro, Delton FS+, Estiseal F, Guardian Seal) were used in this study. Their filler weight content was measured by thermogravimetric analysis. Mechanical properties were measured: dynamic and static moduli of elasticity, flexural strength and Vickers microhardness. Rheological measurements were performed using a dynamic oscillation rheometer. Results: Flowable resin composites have by far better mechanical properties than pit and fissure sealants, except for Delton FS+. All the materials tested are non-Newtonian, shear thinning fluids. They all showed elasticity even at the lowest frequencies but elasticity differs pretty much from one material to another. Significance: : Resin-based pit and fissure sealants seem appropriate for preventive pit and fissure sealing. For enlarged fissures, it can be assumed that flowable resin composites with low elasticity at low frequency are more appropriate. [Copyright &y& Elsevier]

Commercially available polydimethylsiloxane (PDMS) elastomers, such as Sylgard 184® are widely used in soft lithography and for microfluidic applications. These PDMS elastomers contain fillers to enhance their mechanical stability. The reinforcing fillers, often sub-micrometer small SiO particles, tend to aggregate, swell with water, and thereby become cognoscible in a way that can strongly interfere with the visualization of micro-scale events taking place next to PDMS structures. As PDMS microfluidics are often used for studying cells and micro-/nanoparticles and for creating/handling nanodroplets, it has become highly desirable to employ a PDMS having high optical quality and that allows microscopy observation without artifacts. Here, we present a PDMS formulation that is free of fillers and has sufficiently low viscosity to perform a filtration step of the mixed prepolymers before curing. By molding a bi-layer microfluidic network (MFN), composed of a thin filler-free PDMS layer and a thicker Sylgard 184® backing layer, PDMS MFNs featuring both high optical quality and mechanical stability, can be fabricated. [ABSTRACT FROM AUTHOR]

Abstract: Objectives: The purpose of this study was to investigate the rheological behavior of resin composites and to evaluate the influence of each component, organic as well as inorganic, on their viscoelastic properties by testing model experimental formulations. Methods: Several unfilled mixtures of 2,2-bis-[4-(methacryloxy-2-hydroxy-propoxy)-phenyl]-propane (Bis-GMA) and triethylene glycol dimethacrylate (TEGDMA) were prepared as well as experimental flowable resin composites using a Bis-GMA/TEGDMA 50/50wt% mixture as organic fraction filled at 60% in weight with varying ratios of silanated barium glass (1μm) and partially hydrophobic fumed silica (0.1μm). Their rheological properties were investigated using dynamic oscillatory rheometers. Transmission electron microscopy (TEM) was also performed to investigate the spatial organization of the filler particles. Results: Unfilled Bis-GMA/TEGDMA mixtures all showed a Newtonian behavior. The experimental flowable resin composites were non-Newtonian, shear-thinning fluids. As the quantity of microfiller increased, the viscosity increased and the shear-thinning behavior increased as well. In addition, the experimental composites showed thixotropy, i.e. their viscosity is a function of time after deformation. All these properties were not specifically linked to the creation and destruction of a visible network between inorganic particles, as no difference could be seen between particles’ spatial organization at the equilibrium rest state or immediately after deformation. Significance: The complex viscoelastic properties of resin composites are due to interactions between microfiller and monomer molecules. Modifying the chemical and physical properties of the particles’ surface could possibly improve their flow properties and thus their clinical handling performances. [Copyright &y& Elsevier]

Aging in speech production is a multidimensional process. Biological, cognitive, social, and communicative factors can change over time, stay relatively stable, or may even compensate for each other. In this longitudinal work, we focus on stability and change at the laryngeal and supralaryngeal levels in the discourse particle euh produced by 10 older French-speaking females at two times, 10 years apart. Recognizing the multiple discourse roles of euh, we divided out occurrences according to utterance position. We quantified the frequency of euh, and evaluated acoustic changes in formants, fundamental frequency, and voice quality across time and utterance position. Results showed that euh frequency was stable with age. The only acoustic measure that revealed an age effect was harmonics-to-noise ratio, showing less noise at older ages. Other measures mostly varied with utterance position, sometimes in interaction with age. Some voice quality changes could reflect laryngeal adjustments that provide for airflow conservation utterance-finally. The data suggest that aging effects may be evident in some prosodic positions (e.g., utterance-final position), but not others (utterance-initial position). Thus, it is essential to consider the interactions among these factors in future work and not assume that vocal aging is evident throughout the signal. [ABSTRACT FROM AUTHOR]

Abstract: Modified Yoldas sols can be used to prepare crack-free well adherent layers on different substrate materials such as soda–lime glass, corundum and metal (IN-718). These layers having thicknesses of 0.6 µm are strain tolerant and withstand thermal cycling between 810 °C and room temperature. Introducing alpha-Al2O3 filler particles into modified Yoldas sols allows the preparation of thicker layers of 1.6 µm, which as well can be thermally cycled without noticeable delaminations. Chemical bonding seems to be the predominant layer bonding mechanism. [Copyright &y& Elsevier]

Abstract: Objectives: The aim of this study is to compare the wear resistance and hardness of two dental nanohybrid composites and to evaluate the influence of artificial saliva storage on those properties. Methods: Specimens were made from two commercial nanohybrid dental composites (Esthet-X®-Dentsply and Filtek Supreme®-3M). Abrasion tests were carried out in a ball-cratering machine (three body abrasion) and microscopic analysis of the wear surfaces was made using optical and scanning electron microscopy; hardness was quantified by Vickers hardness test. Those tests were repeated on specimens stored in artificial saliva. Results: Results show that the wear rate of the studied materials is within 10−7 mm3/Nmm range, one of the composites presenting wear rate twice as large as the other. After storage in artificial saliva, the wear resistance increases for both materials. Microhardness of the composites is around 52 and 64HV, Esthet-X® presents higher hardness values than Filtek Supreme®. After storage in artificial saliva, the microhardness of both materials decreases. Data were analyzed using ANOVA test, p ≤0.05. Conclusions: Artificial saliva storage increases the materials’ wear resistance, suggesting that in both materials bulk post-cure takes place and saliva absorption occurs only on the surface of the composites. This effect was confirmed by comparing the Vickers hardness before and after artificial saliva treatment and FTIR analyses. Surface microhardness of the composites decreases after storage in artificial saliva whereas bulk microhardness of the materials increases. [Copyright &y& Elsevier]

Abstract: Objectives: The purpose of this research was to determine the viscoelastic properties of commercially available flowable resin composites and resin-based pit and fissure sealants. The weight percentage of filler particles and the morphology of the filler particles were also investigated. Methods: Eight flowable resin composites (Admira Flow, Filtek Flow, FlowLine, Grandio Flow, Point-4 Flowable, Revolution Formula 2, Tetric Flow and X-Flow) and four pit and fissure sealants (Clinpro, Delton FS+, Estiseal F and Guardian Seal) were tested. Rheological measurements were performed using a dynamic oscillation rheometer. The filler weight content was determined by thermogravimetric analysis (TGA) and the morphology of the particles was investigated by scanning-electron microscopy (SEM). Results: Flowable resin composites are non-Newtonian, shear-thinning materials. As the shear rate increased, the complex viscosity decreased drastically. They all showed elasticity even at the lowest frequencies. They also all showed thixotropy. Pit and fissure sealants are non-Newtonian, very low-viscosity fluids. No correlation was found between the rheological properties and the filler weight content or the particles’ shape. Significance: Huge differences are observed in the viscosity and flow characteristics of flowable resin composites that can have a potential influence on their clinical behavior during handling and thus on their clinical indications. Pit and fissure sealants show very different rheological properties from one another. [Copyright &y& Elsevier]

Abstract: Simulations of dense one-component melts of coarse-grained polyethylene (PE) and polyoxyethylene (POE) chains have been modified so that some of the parent chains are collapsed intramolecularly to become filler particles. All intermolecular pairs of beads (filler–filler, filler–matrix, matrix–matrix) interact via exactly the same Lennard–Jones (LJ) potential. Filler particles are obtained by an increase in the strength of the minimum in their intramolecular LJ potential. The response of the mean square radius of gyration, 〈s 2〉matrix, of the free matrix chains to disordered arrangements of the filler particles is evaluated for differences in the compactness and mobility of the filler particles, and for various relationships between the mass of matrix chains and filler particles. Even with this simple model, where distinctive surface—matrix interactions are completely suppressed, the response of 〈s 2〉matrix to the filler particles is complex. It depends on the completeness of the collapse of the chains that represent the filler particles, the mobility of these particles, their concentration, and the relationship between the number of beads in the matrix chains and filler particles. Expansion of the matrix chains is seen when the particles and matrix are both represented by a small number of beads, but contraction of matrix chains can be observed when both species contain a large number of beads. The mobility of the filler particles is likely to be an important issue when they are small, i.e. nanoparticles, and the matrix is not glassy. [Copyright &y& Elsevier]

Abstract: The addition of nano-sized ceramic particles to the plastic crystal ethyl-methyl pyrrolidinium bis(trifluoromethane sulfonyl)amide (P12TFSA) has been investigated by means of DSC and conductivity. The thermal behaviour of the plastic crystal as a function of filler content suggests that the filler particles decrease the onset temperature of the melting slightly at high loadings, however they do not decrease the crystallinity of the material. Furthermore, the IV → III transition decreases in intensity, indicating that the addition of filler increases the possibility for the crystal to remain in metastable rotator phases also at lower temperatures. The conductivity shows a more than one order of magnitude increase with the addition of filler, with a filler concentration dependence that levels out above ∼10 wt.% TiO2. [Copyright &y& Elsevier]

Abstract: The viscoelastic properties of acid milk gels containing small amounts of different fats were investigated. Skim milk was reconstituted from ultra low-heat skim milk powder and emulsions made with 2% (v/v) sunflower oil, olive oil, groundnut oil, or anhydrous milk fat using a pressure homogenizer. Acidification at 20°C for 14h to pH ∼4.6 was achieved by adding glucono-δ-lactone to the emulsion. Stress relaxation testing enabled determination of the firmness and the solid-like properties, i.e., elasticity. Regardless of the physical state of the fat, emulsion gels exhibited higher firmness than fat-free gels, despite the low fat level used. The firmness of the gels containing this small quantity of fat was more sensitive to temperature than was the firmness of fat-free gels. The relaxation time was higher in the presence of fat crystals. Modifications in the rheological properties of gels containing fat were attributed to fat droplets acting as active filler particles. [Copyright &y& Elsevier]

Abstract: Simulations of dense melts of coarse-grained chains have been modified so that they contain filler particles. Since the filler particles and matrix chains are constructed from the same repeat unit, all of the intermolecular energetic interactions in the system (filler–filler, filler–matrix, matrix–matrix) are identical. The collapse of individual chains to form filler particles is achieved by a simple modification in the strength of the minimum in the Lennard–Jones potential governing pair-wise intramolecular interactions within a filler particle. Even when completely collapsed, the filler particles retain mobility in their internal degrees of freedom. Their centers of mass are also mobile. The filler particles can be collapsed completely to dense, impenetrable objects, but they can also be collapsed incompletely to produce permeable filler particles. There is no evidence for spontaneous aggregation of impermeable filler particles, but sufficiently permeable filler particles can aggregate. The parameters used in the simulations insure that the aggregation cannot be energetically driven. Matrix chains that fill space within a permeable filler particle have severe restrictions placed on their available conformations. The reduction in the conformational entropy of the matrix chains can be alleviated if the permeable filler particles interpenetrate, or aggregate. Then fewer matrix chains must enter the permeable filler particles in order to maintain the density of the system. The simulation detects no aggregation of impermeable filler particles because it is not necessary for matrix chains to enter completely collapsed particles. [Copyright &y& Elsevier]

A process was developed for the microencapsulation of inorganic filler particles with poly-methyl-methacrylate, to increase the interaction between the hydrophilic filler particles and a polymer matrix. The filler utilised was aluminium hydroxide with an average diameter of 1.9 µm and a specific surface area of 5 m2/g. The process comprised a surface modification, in which a monolayer of isopropoxy titanium isostearate was chemically bound to the surface to render it hydrophobic and to ensure a chemical bond between the filler and the organic phase. Then, an encapsulation reaction was carried out by means of an emulsion-like polymerization process at monomer starved conditions. The modified particles were stabilized in water with sodium-dodecyl-sulphate. A redox system consisting of cumene-hydroperoxide in combination with sodium-formaldehyde-sulphoxylate and iron(II) salt was applied for the initiation of the polymerization. Besides surface polymer, free polymer particles were also formed. The parameters which varied were the filler concentration, the concentration of the initiator components and the surfactant concentration. At optimum conditions, ~50% of the added monomer polymerized at the modified filler surface, thus forming encapsulated filler particles. SEM together with TGA analysis indicated that a smooth polymer layer had been formed on the filler surface. At high filler loading, however, coagulation occurred. [ABSTRACT FROM AUTHOR]

Influences of rigid (glass) and deformable (gellan) particles dispersed in gellan gels were studied to better understand the effect of structure on the rheologlcal properties of model composite foods. Composites with inclusions at 0%, 10%, 20%, and 30% volume tractions (VF) were tested under small deformation oscillatory shear. In gels containing rigid particles, the dynamic shear storage modulus (G′) decreased initially, exhibited a minimum around 20% VF, then Increased at 30% VF behavior that was attributed to physical Interactions among particles. In gels containing deformable particles, the linear decrease In G′ with increasing VF may be due to particle compliance under stress or to particle separation from the matrix, thereby causing gel weakening. [ABSTRACT FROM AUTHOR]