Terms Of Sorption Research Articles

Solubility, Water Sorption, and Shear Bond Strength of Contemporary Pulp Capping Agents Biodentine, TheraCal LC, and Bioactive Glass Nanoparticles to the Composite Resin Restoration

Aims: Assessing the solubility, water sorption (WS), and shear bond strength (SBS) of contemporary pulp capping agents i.e., Biodentine, TheraCal LC, and Bioactive glass nanoparticles (BGn) bonded to the composite resin restoration as compared to the Dycal. Methods: Forty acrylic resin blocks with a center ditch were fabricated. Each block was then randomly allocated into four groups based on the type of pulp capping cement filled in the prepared ditch (n = 10) Group 1: Dycal, Group 2: Theracal LC, Group 3: Biodentine, and Group 4: BGn. A two-step etch and rinse adhesive along with nanohybrid universal composite were then bonded and built as a 2 mm restoration. SBS and failure mode analysis were performed using a universal testing machine (UTM) and stereomicroscope. Five disks were meticulously manufactured from each tested type of cement for solubility and WS analysis. ANOVA followed by a Tukey post hoc test evaluates the statistical significance of the SBS between restoration and pulp capping material Results: TheraCal LC exhibited the highest SBS values (7.99±0.65 MPa). However, the Dycal demonstrated the lowest bond integrity (1.46±0.19 MPa). Biodentine (14.11±0.58%) displayed the most solubility and TheraCal LC was identified as the least soluble pulp capping agent (3.99±0.41%). Biodentine (12.60±1.15%) demonstrated maximum WS whereas BGn (5.12±0.35%) unveiled the minimum WS. Conclusion: BGn cement displayed satisfactory outcomes in terms of SBS, solubility, and water sorption among all the tested cements. TheraCal LC also exhibited desirable properties of pulp capping agent. However, its water sorption is higher than Dycal.

Characterization and transport properties of ceramic filler incorporated natural rubber composites

AbstractCrystalline glass–ceramic fillers were prepared from calcium carbonate, silica, alumina, and calcium fluoride by heating and subsequent quenching in cold water. The fillers were incorporated into natural rubber (1,4‐cis‐polyisoprene) and the filled rubber composites were crosslinked with sulfur in the presence of different rubber additives. The unfilled and filled rubber composites were characterized. The transport properties of benzene, toluene, and p‐xylene (BTX) through the rubber composites were studied in terms of sorption, diffusion, permeation, and mass transfer coefficients. The effect of the ceramic fillers on the mechanical, thermal and transport properties were studied. The sorption data at different temperatures were used for calculating activation energy of diffusion, permeation, free energy, and enthalpy of sorption. The BTX remained in the liquid state within the composite matrix as evident from negative ΔS. The diffusion coefficient (D) and mass transfer coefficient (kmtc) of BTX decreased with the increase in filler loading. Accordingly, for the transport of BTX the unfilled rubber showed a D (D × 107 cm2/s) and mass transfer coefficient (kmtc × 104 cm/s) of 5.67/3.97/2.96 and 7.71/7.08/7.04, respectively which decreased to 5.06/2.95/2.57 and 7.53/6.95/6.90, respectively for the composite containing 50 wt.% ceramic filler.

Development of poly(methyl methacrylate)/poly(lactic acid) blend as sustainable biomaterial for dental applications

Poly(lactic acid) (PLA) is gaining popularity in manufacturing due to environmental concerns. When comparing to poly(methyl methacrylate) (PMMA), PLA exhibits low melting and glass transition temperature (Tg). To enhance the properties of these polymers, a PMMA/PLA blend has been introduced. This study aimed to investigate the optimal ratio of PMMA/PLA blends for potential dental applications based on their mechanical properties, physical properties, and biocompatibility. The PMMA/PLA blends were manufactured by melting and mixing using twin screw extruder and prepared into thermoplastic polymer beads. The specimens of neat PMMA (M100), three different ratios of PMMA/PLA blends (M75, M50, and M25), and neat PLA (M0) were fabricated with injection molding technique. The neat polymers and polymer blends were investigated in terms of flexural properties, Tg, miscibility, residual monomer, water sorption, water solubility, degradation, and biocompatibility. The data was statistically analyzed. The results indicated that Tg of PMMA/PLA blends was increased with increasing PMMA content. PMMA/PLA blends were miscible in all composition ratios. The flexural properties of polymer blends were superior to those of neat PMMA and neat PLA. The biocompatibility was not different among different composition ratios. Additionally, the other parameters of PMMA/PLA blends were improved as the PMMA ratio decreased. Thus, the optimum ratio of PMMA/PLA blends have the potential to serve as novel sustainable biomaterial for extensive dental applications.

Optical Gain Switching by Thermo‐Responsive Light‐Emitting Nanofibers through Moisture Sorption Swelling

AbstractThe development of intelligent photonic systems made of stimuli‐responsive materials, i.e., with features tunable and switchable by environmental signals, is gaining increasing attention. Here, the study reports on switchable optical gain based on complex arrays of nanofibers made of thermo‐responsive poly(2‐n‐propyl‐2‐oxazoline), incorporating a blue‐emitting chromophore. The fluorescent component endows the nanofibers with optical gain in addition to the moisture absorption capability of the polymer. Light amplification is found with temperature‐ and humidity‐dependent excitation threshold. The threshold value is halved close to the polymer cloud point temperature, enabling reversible switching of the emission intensity upon temperature change. Waveguiding analysis by back‐focal plane imaging on individual fibers allows the switching mechanisms to be rationalized, in terms of moisture sorption swelling‐induced morphological changes. These responsive light‐emitting nanofibers may find application in a novel class of lasers with dynamically‐controlled properties, environmentally‐switchable optoelectronics, and smart sensors.

Mucoadhesive and Antimicrobial Allantoin/β Cyclodextrins-Loaded Carbopol Gels as Scaffolds for Regenerative Medicine.

Allantoin and its β-cyclodextrin and hydroxypropyl-β-cyclodextrin inclusion complexes 1:1 have been used to prepare carbopol-based mucoadhesive gels. The gelation process occurred by adjustment with glycerol 10% in the presence of triethanolamine. The structural features induced by the presence of allantoin and the corresponding β-cyclodextrins inclusion complexes have been first investigated by infrared spectroscopy highlighting strong interactions within the gels network and ideal crosslinks for the self-healing behavior. The hydrophilicity of the gels was investigated by the determination of the surface tension parameters and the free energy of hydration. The interfacial free energy values indicated prolonged biocompatibility with blood. The gels-water molecule interactions in terms of sorption, permeability, and diffusion coefficients were evaluated by dynamic vapor sorption analysis. The self-assembly process through intermolecular H-bonding, the high hydrophilicity, the mechanical performance, the hydrolytic stability in simulated biological media, the biocompatibility with normal human dermal fibroblast (NHDF) cells, the mucoadhesivity and antimicrobial activity on selected microorganism species (S. Aureus and C. albicans) of the allantoin-based gels recommend them as promising scaffold alternatives in regenerative medicine.

In vitro comparative study of sorption and solubility of three modified glass ionomer cements

Aim: To evaluate and compare the sorption and solubility of three modified glass ionomer cements –Glass Hybrid Restorative System (Equiaforte), Zirconomer Improved and resin modified glass ionomer cement (RMGIC) in artificial saliva. Materials And Methods: A total of 45cylindrical specimens (4mm diameter and 6mm height) were prepared for each material following the manufacturer’s instructions. After subjecting the specimens to thermocycling of 500 cycles between 5 and 55 degree Celsius with the dwell time 15secs,45 specimens evaluated for sorption and solubility, first weighing them by a precision weighing scale (W1), then immersing them in artificial saliva for 28days and weighing them(W2), and finally dehydratingin an oven for 24 hours and weighing them(W3). Since the obtained values show normal distribution differences between the groups data were analyzed using the one way analysis of variance (ANOVA). For pairwise evaluation between the groups post hoc dunnet t3 test was used. Results: The sorption and solubility values in artificial saliva were minimum for zirconomer improved glass ionomer cement with the mean value of sorption 52.91 ± 1.73 µg/mm3 and solubility 10.47 ± 1.52 µg/mm3 when compared with other groups.The difference between groups was found to be statistically significant (p<0.05) in terms of sorption and solubility.

Development and characterisation of sugarcane bagasse nanocellulose/ PLA composites

ABSTRACT Nanocellulose from sugarcane bagasse fibres was isolated via chemo-mechanical method subjected to preparation of its PLA-based bionanocomposites using an Injection moulding process with varying weight percentages of nanocellulose. The mechanical properties (i.e. tensile, flexural, fracture toughness, and impact), thermal property (TGA analysis) and dynamic mechanical properties (i.e. storage modulus, loss modulus, and damping) of the prepared bionanocomposites were studied. In addition, water absorption behaviour in terms of maximum water uptake and sorption, diffusion and permeability coefficients of the bionanocomposites were also investigated. Anoticeable improvement in thermal stability, water resistance, and mechanical performance was seen in bionanocomposites with 2 wt. % of nanocellulose. There were 41.44%, 26.21%, 89.79%, and 16.38% improvements in tensile strength, flexural strength, fracture toughness and impact strength, respectively, for 2 wt. % of nanocellulose reinforcement composite over neat PLA matrix. ANOVA analysis was also performed and found that contents of nanocellulose have asignificant impact on the mechanical properties of the bionanocomposites.

Sustainable, hydrophobic, and reusable paper waste aerogel as an effective and versatile oil absorbent

The direct use of environmental paper waste (PW) to create spongy aerogel intended for oil absorption is an interesting green chemistry technique. The oil sorption response, on the other hand, is constrained by a poor oil sorption capacity and lack of stability. To address these concerns for the time being, silica aerogel is being used. Our goal is to use PW aerogel to replace silica aerogels. We made an environmental PW-based aerogel by dispersing PW, polyvinyl alcohol (PVA), and glutaraldehyde (GA). In terms of oil sorption the hybrid PW aerogel performs wonderfully. Notably, it displayed a significant absorption capacity towards various oils of approximately 49–110 times its own mass, dependent on the thickness and density of the oil and solvents within 15–35 s, 25 °C, and 2 × 2 cm dimensions. Additionally, owing to the high sponginess (99.95%), and less density (0.0114 g/cm3), tight bonding between PW and PVA occurs. As a results, the spongy aerogel has an oleophilic nature, superior mechanical power, and high thermal strength. The consistent fibrillar pore linkage gives a high surface to volume ratio, low surface energy, as well as high surface roughness, the aerogel undergoes minimal structural change after numerous recycles. All of these elements have a role in excessive oil absorption.

Comprehensive analysis on anomalous phenomenon of ethanol‐soluble poly(vinyl butyral) membrane for ethanol recovery via pervaporation

AbstractPoly(vinyl butyral) (PVB) is selected as a promising ethanol‐permselective membrane based on the solubility parameter theory; however, it exhibits anomalous water perm‐selectivity in practical pervaporation (PV) process. Comprehensive analysis based on experimental and theoretical methods were carried out to explore the inherent mechanism of the anomalous performance. Firstly, sum frequency generation vibrational spectra and contact angle were developed to quantify the surface reconstruction of membrane in air and ethanol, which indicated that hydrophilic hydroxyl tended to expose on membrane surface with ethanol thus improving the membrane affinity to water. Meanwhile, swelling behaviors proved more water would accumulate in the ethanol swollen membrane. Furthermore, theoretical analysis in terms of sorption and diffusion process, based on the UNIFAC‐FV model and Fujita free‐volume theory, confirmed the mechanism of anomalous phenomenon of PVB membrane. The comprehensive investigation was expected to provide insights into the basic separation mechanism of PV process.

Sorption Properties of ZrO2-Analcime Composites in Relation to Cs(I) and Sr(II)

Composite zeolite sorbents based on analcime with inclusions of hydrated zirconium dioxide (ZrO2-analcime) have been obtained by hydrothermal treatment of coal fly ash cenospheres with a high glass phase content in the presence of a zirconium compound and an alkaline activating agent at 150 °C and different stirring modes of the reaction mixture. The synthesis products were characterized by XRD, SEM-EDS, STA and low-temperature nitrogen adsorption; their sorption properties with respect to Cs+ and Sr2+ were studied in the pH range of 2–10. It was found that the ZrO2-analcime compositions surpass unmodified analcime by 2–5 times in terms of sorption of Cs+ and Sr2+ and by two orders of magnitude in terms of the distribution coefficient value (KD ~106 ml/g). The process of high-temperature solid-phase transformation of Cs+/Sr2+-exchanged forms of the compositions was studied, which simulates the process of conversion of water-soluble forms of Cs‑137 and Sr‑90 radionuclides into a mineral-like form. It was shown that at 1000 °C the ZrO2-analcime compositions with sorbed Cs+ and Sr2+ undergo the phase transformation resulting in polyphase systems of similar composition based on nepheline, tetragonal ZrO2, and glass phase

Effect of cadmium sorption by river sediments on longitudinal dispersion

Abstract This paper concerns the cadmium sorptive effects by river bed sediments on longitudinal dispersion coefficient in an open-channel flow via experimental and numerical study. For this purpose, a circular flume was used with mean diameter of 1.6 m and a width of 0.2 m. The adsorbing bed was considered as a thin layer of the sediment particles with mean diameter of 0.53 mm and three sediment concentrations of 3, 12, and 20 gr/lit. To determine the sorption parameters of the sediments, some experiments were conducted with three cadmium concentrations of 150, 460, and 770 ppb. Then, the dispersion experiments were carried out with and without the bed sediments with the same cadmium concentration as the sorption experiments. A numerical model was then developed to solve the advection–dispersion equation with considering the sorption term by river bed sediments. The longitudinal dispersion coefficients were estimated by comparing the experimental and numerical breakthrough curves. The results showed that, with increasing the sediment concentrations, the sediment sorption rate increased and the longitudinal dispersion coefficient decreased by about 38, 36 and 33 percent, respectively, for cadmium concentrations of 150, 460 and 770 ppb. In addition, by increasing the cadmium concentrations, the changes in the longitudinal dispersion coefficient are decreased. Furthermore, a relationship was developed using non-dimensional longitudinal dispersion as a function of the new parameter of sorption ratio. From a practical point of view, the results of this study demonstrated that, at the presence of riverbed sediment, the cadmium is longitudinally dispersed with more delay in comparison with no sediment at the river bed.

Characterization of occlusal splint materials: CAD-CAM versus conventional resins

AimThe aim of this in vitro study was to assess the mechanical properties of five commercially available subtractive computer-aided design and computer-aided manufacturing (CAD-CAM) milled splint materials, as well as to compare them with conventional heat-polymerized and autopolymerizing resins used in the construction of conventional splints. Material and methodsFive CAD-CAM milled (ProArt CAD Splint, Therapon Transpa, Temp Premium Flexible Transpa, Cast, and Aqua), one autopolymerizing (Palapress), and one heat-polymerized (Paladon 65) resin materials were evaluated. Flexural strength, E-modulus, Vickers hardness, fracture toughness, fracture work, water sorption, and water solubility were measured. Samples were evaluated after dry and water storage for 30 days at 37 °C. Data were collected and statistically analyzed. ResultsUnder both storage circumstances, the flexural strength values of Paladon 65, Therapon Transpa, Temp Premium Flexible Transpa, and Aqua were statistically non-significant (P=0.055). The polycarbonate-based CAD-CAM material Temp Premium Flexible Transpa had the highest statistically significant values of the fracture toughness and fracture work (P<0.001). Moreover, it exhibited the lowest percentages of water sorption and water solubility among the investigated materials (P<0.001). All of the CAD-CAM materials exhibited dry elastic moduli greater than Palapress and lower than Paladon 65. One of the CAD-CAM materials, Cast, had the highest dry Vickers hardness value, which was non-significant when compared to Therapon Transpa (P=0.762). ConclusionCAD-CAM polycarbonate-based splint materials exhibit higher fracture toughness and fracture work as well as lower water sorption and solubility than polymethyl methacrylate-based ones. The mechanical characteristics of the assessed CAD-CAM milled splint materials were not typically superior to those of the conventional heat-polymerized resin. However, some of them outperformed the autopolymerizing acrylic resin in terms of flexural strength, surface microhardness, water sorption, and water solubility.

Crack properties, toughness and absorption evaluation of FRCC incorporating reclaimed asphalt pavement and crumb rubber as aggregates

The development and application of fibre-reinforced cementitious composites (FRCC) have evolved significantly over the last decade. However, there is a need to find innovative ways to improve the sustainability of composites. The production and transportation of the major binder (i.e. Portland cement) and aggregates used for FRCC consumes high energy and natural resources. Therefore, finding ways to incorporate recycled materials to replace these conventional components can be used to improve the sustainability of the FRCC. Also, the special micro silica sand used to produce certain types of FRCC is a major concern due to its limited availability and higher cost. On the other hand, there exist various waste materials that can be incorporated into FRCC as a replacement of either the binder or aggregate. Hence this current paper aims to investigate the performance of FRCC made with high volume fly ash as partial replacement of Portland cement, and reclaimed asphalt pavement/crumb rubber as replacement of the natural aggregates. The performance of the FRCC incorporating these recycled materials was evaluated in terms of its crack properties, toughness and sorption. Results from this study showed that the use of recycled crumb rubber is beneficial in terms of crack properties and lower sorption. The sorption of FRCC incorporating crumb rubber as the only aggregate was reduced by 31.8%. However, FRCC made with reclaimed asphalt pavement exhibited higher sorption and lower toughness.

Effects of Water and Chemical Solutions Ageing on the Physical, Mechanical, Thermal and Flammability Properties of Natural Fibre-Reinforced Thermoplastic Composites.

Biocomposites comprising a combination of natural fibres and bio-based polymers are good alternatives to those produced from synthetic components in terms of sustainability and environmental issues. However, it is well known that water or aqueous chemical solutions affect natural polymers/fibres more than the respective synthetic components. In this study the effects of water, salt water, acidic and alkali solutions ageing on water uptake, mechanical properties and flammability of natural fibre-reinforced polypropylene (PP) and poly(lactic acid) (PLA) composites were compared. Jute, sisal and wool fibre- reinforced PP and PLA composites were prepared using a novel, patented nonwoven technology followed by the hot press method. The prepared composites were aged in water and chemical solutions for up to 3 week periods. Water absorption, flexural properties and the thermal and flammability performances of the composites were investigated before and after ageing each process. The effect of post-ageing drying on the retention of mechanical and flammability properties has also been studied. A linear relationship between irreversible flexural modulus reduction and water adsorption/desorption was observed. The aqueous chemical solutions caused further but minor effects in terms of moisture sorption and flexural modulus changes. PLA composites were affected more than the respective PP composites, because of their hydrolytic sensitivity. From thermal analytical results, these changes in PP composites could be attributed to ageing effects on fibres, whereas in PLA composite changes related to both those of fibres present and of the polymer. Ageing however, had no adverse effect on the flammability of the composites.

Discoloration Behavior of Resin Cements Containing Different Photoinitiators.

The purpose of this study was to evaluate the sorption, solubility, and color stability of amine-free conventional light-cure and dual-cure resin cements and an amine-containing self-adhesive dual-cure resin cement. Sixty specimens were prepared using a light-cure resin cement (Variolink Esthetic LC, Ivoclar Vivadent; VE-LC), a dual-cure resin cement (Variolink Esthetic DC, Ivoclar Vivadent; VE-DC), and a self-adhesive dual-cure resin cement (RelyX U200, 3M ESPE; RXU200). The water sorption and solubility were tested by immersing the specimens in distilled water for 7 days. Kruskal-Wallis test was applied to the data. ΔE values of 1-day and 7-day immersion in black tea were analyzed using one-way analysis of variance followed by Tukey honest significant difference test (n = 10). There was no statistically significant difference among the groups in terms of sorption and solubility. The mean ΔE of RXU200 for the 0/1 and 0/7 days were found to be significantly lower than that of VE-LC and VE-DC (P < .05). ΔE values of the VE-LC and VE-DC groups did not reveal statistical difference. It should be taken into account that discoloration of resin cements remains a problem even with amine-free products.

ESTUDO DE MEIO REATIVO PARA BARREIRAS REATIVAS PERMEÁVEIS (BRP): ENSAIOS LABORATORIAIS

Esse manuscrito apresenta resultados de estudos laboratoriais para avaliar a adequabilidade de zeólitas como meio reativo de Barreiras Reativas Permeáveis (BRPs), em 3 faixas granulométricas (4,0x10-4 a 1,0x10-3 m, 1,0x10-3 a 2,0x10-3 m e 1,0x10-3 a 3,0x10-3 m). Estudos foram desenvolvidos por meio da caracterização física, química, mineralógica, permeabilidade e de sorção. A zeólita caracterizada é da espécie Clinoptilolita, com peso específico dos sólidos de 22,87 kN/m3, razão Si/Al de 6,8 e capacidade de troca catiônica de 180 cmolc/kg. Os diferentes arranjos volumétricos das partículas geraram valores de peso específico aparente seco de 10,01 a 11,00 kN/m3 e condutividades hidráulica saturada de 1x10-5 a 3x10-4 m/s, o que compatibiliza os arranjos com diferentes meios geológicos. Em termos de sorção, a isoterma do tipo Langmuir ajusta com r2 de 0,997 e, quanto a cinética de adsorção, o comportamento ocorre por meio do compartilhamento de elétrons entre zeólita e soluto, com coeficientes de reação de primeira ordem variando de 0,06 a 0,4h-1 em função do tempo de percolação. Os resultados mostram que as zeólitas nas faixas granulométricas estudadas são adequadas para uso como meio reativo de BRP em espessuras economicamente viáveis para áreas contaminadas inseridas em materiais geológicos relativos à Formação Botucatu.

Kinetics of sorption in bio-based materials: theory and simulation of a demonstrator wall

The classical models describing hygric transport inside building materials seem unsuitable for bio-based materials. Based on the assumption of an instantaneous local equilibrium between relative humidity and water content evolving according to the sorption isotherms, they predict much shorter stabilisation times than those obtained experimentally. A new approach is presented here: it frees from the local instantaneous equilibrium by introducing local kinetics to describe the transformation of water from the vapour state to the absorbed liquid state and vice versa. In the framework of the European IsoBio project, a multilayered wall mainly made of bio-based materials was developed. The different layers were characterised in terms of sorption, vapour permeabilities and thermal conductivities. The sorption measurements performed on representative samples allowed determination of the local kinetic constants. The hygrothermal behaviour of the test wall was then studied in an instrumented demonstrator (Hive, Wroughton, UK). The recorded measurements were compared with simulations based on the instantaneous local equilibrium model (TMC code) and on the local kinetics of sorption model (TMCKIN code). TMC very significantly underestimated the dynamics of the local relative humidity variations whereas TMCKIN succeeded in predicting these dynamics and produced results close to measurements.

Coupling of transient matrix diffusion and pore network models for gas flow in coal

Processes of sorption and diffusion play a critical role in the analysis and simulation of coal seam gas (CSG) reservoirs since most of the gas reserves are held by the coal matrix. Thus, it is essential to understand the displacement of gas in coal matrix and fractures. This can be formulated in terms of sorption and diffusion processes inside the matrix and advective flow in the cleats. The multi-scale porous structure and multi-physics nature of gas flow in coal complicate numerical modelling of these phenomena. A novel approach is developed to solve this problem by coupling conventional pore network modelling (PNM) with transient diffusion flow. The coupling is undertaken for each pore network throat separately by utilising the Finite Volume Method and Fick's second law of diffusion. The Langmuir isotherm is employed to describe sorption processes within the coal matrix and to link the concentration and pressure values when coupling the diffusion model with PNM. The proposed approach provides the possibility to account for the transient nature of gas transport across the different scales, while limiting the number of unknowns in the simulation to an effective diffusivity parameter. Our results demonstrate that steady-state pore network models can be effectively coupled with a transient phenomenon such as Fick's diffusion allowing to estimate the diffusive constitute of the matrix to the total gas flow in coal over time. The obtained gas sorption capacity and its release rate can then be used to accurately estimate the time-dependent production profile of CSG reservoirs.

Dehumidification Effect of Polymeric Superabsorbent SAP-LiCl Composite Desiccant-Coated Heat Exchanger with Different Cyclic Switching Time

This study investigated a composite polymer desiccant material’s performance, which is prepared by impregnating solid desiccant such as sodium polyacrylate (SAP) on to hygroscopic salts such as lithium chloride (LiCl). Dehumidification performance of the proposed composite polymer desiccant (SAP-LiCl) was analyzed by coating the suitable weight percentage (wt %) of the desiccant onto a single fin-tube heat exchanger (FTHE) system and testing the desiccant-coated heat exchanger (DCHE) in a testing tunnel under various operating conditions. Net dehumidification efficacy of DCHE in terms of sorption and desorption amount and thermal performance (COPth) were analyzed. For instance, with processed air inflow temperature, relative humidity and regeneration temperature setting of 30 °C, 80% RH and 70 °C, DCHE’s sorption, desorption amount and COPth were recorded as high as 945.1 g, 1115.1 g, and 0.39, respectively. It was further realized that the performance of the DCHE could be enhanced by modulating the cyclic switching time for dehumidification and regeneration processes. For instance, with the aforementioned processed airflow conditions, when the cyclic switching time tuned as 60 min instead of 10 min for a total time period of 120 min, there is a net 58% improvement to the COPth of the system. It was further observed that, under the same time period corresponding to the increase in cyclic switching time, the overall COPth can be enhanced; however, the water vapor sorption and desorption amounts of desiccant were decreased.

Multifactorial analysis of optical properties, sorption, and solubility of sculptable universal composites for enamel layering upon staining in colored beverages.

To analyze the effects of factors 'composite,' 'medium,' and 'time' on color, translucency, and sorption/solubility of sculptable universal composites for enamel layering upon immersion in colored beverages. Disk-shaped specimens, 10 mm in diameter and 2 mm thick (n=5/group), of ultrafine, hybrid composite Essentia (GC), microhybrid Gaenial Anterior (GC), nanofilled Filtek Ultimate Enamel and Body ( 3M ESPE) were immersed in red wine, coffee, or distilled water for 15 days. CIELab color coordinates were measured and CIEDE2000 (∆E00 ) and Translucency Parameter differences (∆TP00 ) were calculated. Sorption and solubility were determined according to ISO 4049:2009. Data were analyzed using the analyses of variance and Tukey's post-hoc test (α=0.05). Essentia and Gaenial exhibited the lowest and the highest staining-dependent color differences, with mean ∆E00 range of 1.7-6.1 and 5.1-11.3, respectively (p < 0.05). ∆TP00 was more pronounced in wine than in coffee (p < 0.05). Sorption and solubility varied between 9.8 and 15.3μg/mm3 and -1.6 and -5.4μg/mm3 , respectively, with positive correlation between ∆TP00 and sorption (p=0.005). Total color and translucency differences of sculptable composites for enamel layering were material-, time- and medium-dependent. Translucency differences positively correlated with sorption. Overall, the ultrafine, hybrid composite exhibited the best results in terms of color stability, sorption and solubility. Clinicians should be aware of differences in color stability of sculptable composites for enamel layering as these are directly exposed to discoloration in the oral environment and are directly related to patients' long-term satisfaction and restoration longevity. Ultrafine, hybrid composite may be preferred due to better color stability, lower sorption and solubility compared to nanofilled and microhybrid composites evaluated in this study.