Diametral Tensile Strength Research Articles

Effect of carbon nanotube incorporation on the mechanical and physical properties of hydroxyapatite/glass ionomer nanocomposite

This manuscript discusses the potential use of multi-walled (MW) carbon nanotubes (CNTs) as a filler material in hydroxyapatite/glass ionomer cement HA/GIC nanocomposite to enhance its properties: mechanical and physical. Four different proportions (1, 2, 3, and 5 wt%) of CNTs were added to the HA/GIC nanocomposite to determine the optimum ratio that can lead to the best properties of the new nanocomposite biomaterial. Mechanical mixing technique followed in dentistry was used in preparing all samples. FTIR, PSA, XRD, TEM, and SEM were used to characterize the fabricated Pellets. In addition, the new nanocomposite samples were evaluated using compressive and diametral tensile tests. Overall, increasing the weight ratio of CNTs added to the nanocomposite (from 1 to 5 wt%) caused about a 40% reduction in the compression strength of the samples. However, a slight increase (about 4%) was detected at 2 wt% CNTs samples. Also, a distinct increase in the elasticity of the composite (about 50%) was reported. The best results of diametral tensile strength were found at a 3 wt% CNTs. Furthermore, for all samples, adding CNTs to the composite changed the sample’s color from A2 and B2 to totally black color.

Physical/mechanical and antibacterial properties of composite resin modified with selenium nanoparticles

BackgroundAccumulation of biofilm over composite resin restorations is one of the principal causes of recurrent caries. Therefore, this study aimed to develop antibacterial composite resins by crystalline selenium nanoparticles (SeNPs), assessing the antibacterial, mechanical, and physical properties of the composite resin after SeNPs incorporation.MethodsSeNPs were synthesized via a green method. The nanoparticles were characterized by UV-Vis spectroscopy, fourier transform infrared (FT-IR) spectroscopy and transmission electron microscopy (TEM). The nano-filled composite (Filtek™ Z350XT ) was considered as a control group (G0). Two concentrations of SeNPs (0.005 wt% and 0.01 wt%.) were added to the tested resin composite (G1& G2), respectively. The physical/mechanical and antibacterial properties of the composite specimens (n = 10/group) were characterized. A one-way ANOVA was conducted to analyze these data followed by Bonferroni post hoc test for pairwise comparison.ResultsModified composites with SeNPs showed antibacterial activity against E. coli and S. mutans. Mechanical properties including diametral tensile strength, compressive strength, or surface roughness were not affected by nano-incorporation compared to control. Furthermore, the degree of conversion showed no statistical difference. However, SeNPs incorporation into resin composite produces color change that can be visually perceived.ConclusionsThe green synthesized SeNPs significantly improved the antimicrobial properties of the dental composite without compromising mechanical performance. However, it shows color change after SeNPs incorporation.

Evaluation of compressive and diametral tensile strength of novel bioactive material with conventional glass ionomer cement and silver amalgam: An in vitro study.

The aim of this study was to compare the compressive and tensile strength of two different brands of conventional glass ionomer cement (GIC), with new zirconia-reinforced GIC and silver amalgam. Eighty specimens with 20 samples in each group were prepared (Group 1-Fuji IX GIC, Group 2-FX-II Shofu GIC, Group 3-Amalgam, and Group 4-Zirconia-reinforced glass ionomer [Zirconomer]) for compressive strength (CS) using cylinder molds with dimensions 6.0 mm diameter × 12.0 mm height. Eighty specimens using cylinder molds with dimensions 6.0 mm diameter × 3.0 mm height were prepared for testing diametral tensile strength (DTS). CS test was carried out using Micro Universal Testing Machine (Mecmesin, PPT Group, UK) having a crosshead speed of 1.0 mm/min. DTS was determined using Instron universal testing machine at a crosshead speed of 1.0 mm/min. The data were submitted to two-way analysis of varianceand post hoc Tukey tests (alpha = 0.05). The mean CS value was more for Group III (256.2), followed by Group IV (181.2 Megapascals [MPa]), Group II (129.8 MPa), and the least was Group I (117.9 MPa). The mean DTS value was high in Group III (73.7 MPa), followed by Group IV (58.0 MPa), Group II (36.0 MPa), and the least was seen in Group I (23.2 MPa). It can be concluded that although Zirconomer has mechanical properties greater than that of unmodified GICs, additional studies are essential to evaluate its long-time ability.

Experimental and Finite Element Analysis of Compressive Strength and Diametral Tensile Strength of Luting Cement: An In Vitro Study.

Background Strength parameters greatly influence the selection of luting agents. This study compared the compressive and diametral tensile strengths (DTS) of three luting cements. Materials and methods Three luting cements, conventional glass ionomer (CGI), resin-modified glass ionomer (RMGI), and resin cement (RC), were tested for compressive strength and DTS. Forty-two standardized specimens were prepared, measuring 4 mm by 6 mm for compressive tests and 6 mm by 3 mm for diametral tensile tests. The luting materials were prepared according to the manufacturers' instructions. Result Experimental mean compressive and diametral strengths and standard errors were calculated for each luting agent (n = 10). Analysis of variance was computed (p < 0.05), and multiple comparison tests were performed. RC showed significantly higher compressive strengths and DTS among the three tested luting cements, while the CGI showed the least. The results obtained by finite element analysis (FEA) for both tests closely matched the experimental results. Conclusion In this study, it was concluded that the mean compressive strength and DTSvalues of all three luting cements were significantly different. The resin luting cement exhibited the highest compressive strength and DTS, while the CGI exhibited the least.

Evaluation and Characterization of some Properties of Glass Ionomer Cement Reinforced by Novel Boron Nitride Nanoplatelets

Purpose: This study characterized and incorporated a novel Boron Nitride Nanoplatelet (BNNP) into conventional cement known as Glass Ionomer Cement (GIC) with changed ratios (range from 1%, 3%, 5%, and 7%wt) Subsequently. Materials and Methods: The study examined the impact of adding BNNP on the mechanical characteristics of GIC, including its Flexural Strength (FS), Diametral Tensile Strength (DTS), water sorption/solubility, and setting times. The BNNP was characterized using Physio-Chemical Characterization, and Brunauer-Emmett-Teller (BET) testing, and density was also measured. In addition to showing considerably greater DTS (16.34± 1.26MPa) and FS (24.037 ± 0.816 MPa), the results showed that 3% wt. BNNP-modified GIC specimens decreased in water sorption/solubility 19.358±2.40 and 2.979±0.65 µg/mm3, respectively, compared with traditional GIC. Results: In this work, a novel BNNP containing GIC was created, resulting in a 15% reduction in water sorption. When compared to commercial GIC, the demonstrated GIC can quadruple the DTS and FS. Conclusion: For water-based cement types, the glass-ionomer formulations including BNNP exhibit equivalent and acceptable working qualities.

Synthesis and Characterization of Sol-Gelled Barium Zirconate as Novel MTA Radiopacifiers.

Barium zirconate (BaZrO3, BZO), which exhibits superior mechanical, thermal, and chemical stability, has been widely used in many applications. In dentistry, BZO is used as a radiopacifier in mineral trioxide aggregates (MTAs) for endodontic filling applications. In the present study, BZO was prepared using the sol-gel process, followed by calcination at 700-1000 °C. The calcined BZO powders were investigated using X-ray diffraction and scanning electron microscopy. Thereafter, MTA-like cements with the addition of calcined BZO powder were evaluated to determine the optimal composition based on radiopacity, diametral tensile strength (DTS), and setting times. The experimental results showed that calcined BZO exhibited a majority BZO phase with minor zirconia crystals. The crystallinity, the percentage, and the average crystalline size of BZO increased with the increasing calcination temperature. The optimal MTA-like cement was obtained by adding 20% of the 700 °C-calcined BZO powder. The initial and final setting times were 25 and 32 min, respectively. They were significantly shorter than those (70 and 56 min, respectively) prepared with commercial BZO powder. It exhibited a radiopacity of 3.60 ± 0.22 mmAl and a DTS of 3.02 ± 0.18 MPa. After 28 days of simulated oral environment storage, the radiopacity and DTS decreased to 3.36 ± 0.53 mmAl and 2.84 ± 0.27 MPa, respectively. This suggests that 700 °C-calcined BZO powder has potential as a novel radiopacifier for MTAs.

Fabrication of Dicarboxylic-Acid- and Silica-Substituted Octacalcium Phosphate Blocks with Stronger Mechanical Strength

Octacalcium phosphate (OCP) is an attractive base material to combine into components developed for medical purposes, especially those used in bone replacement procedures, not only because of its excellent biocompatibility but also because of its ability to intercalate with multiple types of molecular layers such as silica, dicarboxylic acid, and various cations. On the other hand, there are no examples of simultaneous substituting for several different compounds on OCPs. Therefore, in this study, the physical and mechanical strength (DTS: diametral tensile strength) of OCPs substituted with both silica and dicarboxylic acids (thiomalate: SH-malate) were evaluated. By optimizing the amount of SH-malate, we were able to prepare a block consisting of OCPs with both silica and SH-malate supported in the interlayer. The composition of the OCP-based compound comprising this block was Ca8Na1.07H6.33(PO4)4.44(SiO4)1.32(SH-malate)2.40·nH2O. Interestingly, the low mechanical strength, a drawback of silica-substituted OCP blocks, could be improved by dicarboxylic acid substituting. The dicarboxylic acid addition increased the mechanical strength of silica-substituted OCP blocks, and the acid successfully incorporated into the interlayer, even with the presence of silica. These results are expected to advance the creation of better silica-substituted OCPs and improved bone replacement materials.

Effects of TiO2 on the mechanical and physical properties of Fe2O3-Doped Yttria-Stabilized Zirconia for electrolyte of Solid Oxide Fuel Cells

Yttria-Stabilized Zirconia (YSZ) based electrolytes of Solid Oxide Fuel Cell (SOFC) are widely used due to their higher ionic conductivity, stability, and availability. The present study focuses on improving the performance of YSZ-based electrolytes particularly by doping other particles into YSZ. TiO2 was doped into Fe2O3-8YSZ composite and the effects of TiO2 on the mechanical and physical properties of the composites were observed. The concentrations of TiO2 were varied by 0 wt%, 1 wt%, 3 wt%, and 5 wt% for different compositions of the composites. The samples were fabricated by the solid-state reaction method by pressing the powders at 250 MPa for 3 min and were sintered at 1250 °C for 4 h. The sintered samples were then undergone through characterization tests in terms of percentage of volume shrinkage, density, porosity, Diametral Tensile Strength (DTS), and microhardness. The highest values of volume shrinkage (34.83%), relative density (97.83%), DTS (36.58 MPa), hardness (965 HV), and the lowest porosity (2.17%) were found for 5 wt% TiO2 addition. Besides, the lowest values of volume shrinkage (28.44%), relative density (87.94%), DTS (3.24 MPa), microhardness (340 HV), and the highest porosity (12.06%) were found for Fe2O3-8YSZ composites without (0 wt%) TiO2 addition.

Effects of Calcination Temperature on the Synthesis of One-Pot Sol-Gelled Barium Titanate Powder and Its Performance as an Endodontic Radiopacifier.

Barium titanate (BaTiO3, BTO), conventionally used for dielectric and ferroelectric applications, has been assessed for biomedical applications, such as its utilization as a radiopacifier in mineral trioxide aggregates (MTA) for endodontic treatment. In the present study, BTO powders were prepared using the sol-gel process, followed by calcination at 400-1100 °C. The X-ray diffraction technique was then used to examine the as-prepared powders to elucidate the effect of calcination on the phase composition and crystalline size of BTO. Calcined BTO powders were then used as radiopacifiers for MTA. MTA-like cements were investigated to determine the optimal calcination temperature based on the radiopacity and diametral tensile strength (DTS). The experimental results showed that the formation of BTO phase was observed after calcination at temperatures of 600 °C and above. The calcined powders were a mixture of BaTiO3 phase with residual BaCO3 and/or Ba2TiO4 phases. The performance of MTA-like cements with BTO addition increased with increasing calcination temperature up to 1000 °C. The radiopacity, however, decreased after 7 days of simulated oral environmental storage, whereas an increase in DTS was observed. Optimal MTA-like cement was obtained by adding 40 wt.% 1000 °C-calcined BTO powder, with its resulting radiopacity and DTS at 4.83 ± 0.61 mmAl and 2.86 ± 0.33 MPa, respectively. After 7 days, the radiopacity decreased slightly to 4.69 ± 0.51 mmAl, accompanied by an increase in DTS to 3.13 ± 0.70 MPa. The optimal cement was biocompatible and verified using MG 63 and L929 cell lines, which exhibited cell viability higher than 95%.

Sustainably cultured coral scaffold supports human bone marrow mesenchymal stromal cell osteogenesis

The current gold standard grafting material is autologous bone due to its osteoinductive and osteoconductive properties. Autograft harvesting results in donors site morbidity. Coral scaffolds offer a natural autograft alternative, sharing the density and porosity of human bone. This study investigated the biocompatibility and osteogenic potential of a novel, sustainably grown Pocillopora scaffold with human bone marrow-derived mesenchymal stromal cells (MSCs). The coral-derived scaffold displays a highly textured topography, with concavities of uniform size and a high calcium carbonate content. Large scaffold samples exhibit compressive and diametral tensile strengths in the range of trabecular bone, with strengths likely increasing for smaller particulate samples. Following the in vitro seeding of MSCs adjacent to the scaffold, the MSCs remained viable, continued proliferating and metabolising, demonstrating biocompatibility. The seeded MSCs densely covered the coral scaffold with organized, aligned cultures with a fibroblastic morphology. In vivo coral scaffolds with MSCs supported earlier bone and blood vessel formation as compared to control constructs containing TCP-HA and MSCs. This work characterized a novel, sustainably grown coral scaffold that was biocompatible with MSCs and supports their in vivo osteogenic differentiation, advancing the current repertoire of biomaterials for bone grafting.

Comparative Assessments of Dental Resin Composites: A Focus on Dense Microhybrid Materials.

The performance of dental resin composites is crucially influenced by the sizes and distributions of inorganic fillers. Despite the investigation of a variety of functional particles, glass fillers and nanoscale silica are still the predominant types in dental materials. However, achieving an overall improvement in the performance of resin composites through the optimization of their formulations remains a challenge. This work introduced a "dense" microhybrid filler system with 85 wt % filler loading, leading to the preparation of self-developed resin composites (SRCs). Comparative evaluations of these five SRCs against four commercial products were performed, including mechanical property, polymerization conversion, and shrinkage, along with water sorption and solubility and wear resistance. The results showed that among all SRC groups, SRC3 demonstrated superior mechanical performance, high polymerization conversion, reduced shrinkage, low water absorption and solubility, and acceptable wear resistance. In contrast to commercial products, this optimal SRC3 material was comparable to Z350 XT in flexural and diametral tensile strength and better in flexural modulus and surface hardness. The use of a "dense" microhybrid filler system in the development of resin composites provides a balance between physicochemical property and wear resistance, which may be a promising strategy for the development of composite products.

Correlation between fluoride release, surface hardness and diametral tensile strength of restorative glass ionomer cements.

The aim of this study was to determine if there is a correlation between fluoride release, surface hardness, and diametral tensile strength of restorative glass ionomer cements (GICs). Conventional (Riva Self Cure) and resin-modified (Riva Light Cure) GICs were used. Thirty-four samples (ø 6 x 3 mm) were prepared for each cement. The kinetics of fluoride release (n=4) was evaluated over 28 days using a fluoride-selective electrode (ISE 4010-C00). The analysis of surface hardness (n=10) was performed using a microhardness tester (Shimadzu HMV-2000, Japan) with a Knoop indenter and a load of 25 gf for 30 seconds. The diametral tensile strength test (n=10) was conducted on a universal testing machine at a speed of 0.75 mm/min. Fluoride release data were analyzed by two-way repeated measures ANOVA and Bonferroni post hoc test, while independent t-test was used for other analyses (α=0.05). Overall, the groups showed higher fluoride release until day 7 and a progressive decrease until day 28. On day 1 and day 21, Riva Self Cure showed a higher level of release than Riva Light Cure (p=0.026). Riva Light Cure showed higher diametral tensile strength (p<0.0001) and surface hardness (p=0.034) than Riva Self Cure. A negative correlation was found, indicating that higher fluoride release is associated with lower surface hardness and diametral tensile strength. Fluoride release and mechanical performance are related properties of GICs, and these properties exhibit different values depending on the type of material. Resin-modified GIC release less fluoride but exhibit better mechanical performance compared to conventional GIC. Key words:Diametral Tensile Strength, Fluoride, Glass Ionomer Cement, Surface Hardness.

Effects of novel additives on the mechanical and Biological properties of glass ionomer cement: An in vitro study

Aim: To evaluate the efficacy of incorporated novel additives in Glass Ionomer Cement to ameliorate biocompatibility and mechanical properties. Introduction: Though Glass Ionomer Cement (GIC) has multiple advantages, it is not strong enough for medical applications, and its biocompatibility is questionable. To improve biocompatibility and its mechanical properties, a study was performed to investigate the potential benefits of adding graphene, carbon nanotubes, hydroxyapatite, and bioactive glass to GIC. The objective was to enhance both the mechanical properties and biocompatibility of GIC. Material and Method: Modified Glass Ionomer Cement was prepared by creating five groups. Hydroxyapatite, multi-walled carbon nanotubes, graphene, and bioactive glass were incorporated in a 10:1 weight ratio, respectively. Group 5 was designated as the control group and used Fuji Type II GIC. After preparing 90 samples, they were kept in deionized water for a day and then evaluated their compressive strength, microhardness, and diametral tensile strength, and also checked their in vitro cytotoxicity by direct contact with L929 mammalian fibroblast cells. Statistical Analysis: The data were examined using mean and standard deviation descriptive statistics. The comparative evaluation was done via Tukey HSD test and one-way ANOVA using S.P.S.S. software. Result: It showed that Group 3 had better results in compressive strength (144.478+- 3.989), diametral tensile strength (20.29+- 0.8601), and microhardness (131+-3.536) when compared with other groups while in the biocompatibility (viability %) Group 1 [82.55], Group 3 [76.49], Group 4 [87.63], while Group 2[58.02]. Conclusion: Group 3 has better physical properties in microhardness, diametral tensile strength, and compressive strength, than the other groups. In Biocompatibility, Group 1, Group 3, Group 4, and Group 5 were noncytotoxic at the same time multi-walled carbon nanotubes group (Group 2) had cytotoxic potential.

Tensile strength of conventional glass ionomer cement and silver reinforced glass ionomer cement

A comparative analysis and assessment of the compressive strength (CS) and diametral tensile strength (DTS) between conventional glass ionomer cement (C-GIC) and a silver-reinforced GIC (S-GIC) variant is of interest. Ten specimens of both C-GIC (GC Fuji II, Japan) and S-GIC (Riva Silver, SDI, Australia) were fabricated for the evaluation of compressive strength, and an identical number of samples were created for the examination of tensile strength. These specimens were then tested using a universal testing apparatus. The results exhibited that both the compressive and diametral tensile strengths were significantly greater for the S-GIC cement in comparison to the C-GIC, with a notable p-value of 0.001. The findings suggest that S-GIC may be considered a viable alternative to conventional GIC.

The effect of oxygen-inhibited layer and its inhibition technique on diametral tensile strength values of various nanofilled composite resin types

Abstract Aim: To investigate the impact of different inhibitory techniques on the thickness of oxygen-inhibited layer (OIL) and diametral tensile strength (DTS) value in various types of nanofilled composite resins. Materials and Methods: Thirty-six nanofilled composite resins specimens, consisting of packable, flowable, high-viscosity bulk-fill (HVBF), low-viscosity bulk-fill (LVBF), shaped as half disk (diameter: 6 mm and height 3 mm) and randomly allocated to three groups (n = 3): with Mylar strip, glycerin application, and without OIL inhibitors. OIL thickness was observed with an optical microscope. Furthermore, 60 specimens of composite resins were incrementally created in disk-shaped molds (diameter: 6 mm, height: 1.5 mm × 2 mm). DTS measurements were carried out using a universal testing machine. Data were statistically analyzed using a two-way analysis of variance (ANOVA) test and Pearson’s correlation test (P &lt; 0.05). Results: OIL inhibitor techniques (Mylar strip and glycerin) significantly affected OIL formation across various types of nanofilled composite resins (P &lt; 0.05). Changes were also observed in how these techniques influenced DTS values. Correlation analysis indicated a positive relationship between OIL thickness and DTS value. Conclusions: Application of Mylar strip and glycerin reduced OIL thickness and DTS values in packable, flowable, HVBF, LVBF nanofilled composite resins. Glycerin proved to be more effective than Mylar strips in reducing OIL thickness, which is reflected in the DTS values of nanofilled composite resins. Greater OIL layer thickness on the outermost layer of the nanofilled composite resin correlated with a higher DTS value.

Mechanical Properties and Ion Release from Fibre-Reinforced Glass Ionomer Cement.

The aim of this study was to compare the mechanical properties and ion release from a commercially available resin-modified glass ionomer cement to a formulation reinforced by the addition of short glass fibres at various percentages. Methods: Three experimental groups were prepared by adding a mass ratio of 10%, 15% and 20% of short glass fibres to the powder portion of the cement from a capsule (GC Fuji II LC), while the control group contained no fibres. Microhardness (n = 12), fracture toughness, and flexural, compressive and diametral tensile strength (n = 8) were evaluated. To study ion release, readings were obtained utilising fluoro-selective and calcium-selective electrodes after 24 h, 7 days and 30 days (n = 12). The spatial distribution of fibres within the material was evaluated through scanning electron microscopy. The data were analysed using one-way ANOVA with a Bonferroni adjustment. Results: The findings suggest that elevating fibre weight ratios to 20 wt% results in improved mechanical properties (p < 0.05) in microhardness, flexural strength, diametral tensile strength and fracture toughness. In terms of ion release, a statistically significant difference (p < 0.001) was observed between the groups at the conclusion of 24 h and 7 days, when the fluoride release was much higher in the control group. However, after 30 days, no significant distinction among the groups was identified (p > 0.05). Regarding calcium release, no statistically significant differences were observed among the groups at any of the evaluated time points (p > 0.05). SEM showed the fibres were homogeneously incorporated into the cement in all experimental groups. Conclusions: Resin-modified glass ionomer enhanced with short glass fibres at a weight loading of 20% showcased the most favourable mechanical properties while concurrently maintaining the ability to release fluoride and calcium after a 30-day period.

Gallic acid–coated nanolayer on mineral trioxide aggregate for regulating the inflammatory and differentiation cellular response profile of human dental pulp stem cells

Mineral trioxide aggregate (MTA) is a biomaterial used in endodontics due to its high bioactivity, antibacterial behaviors, and good biocompatibility. However, it has several disadvantages related to certain physical properties, including a long setting time and poor mechanical properties. Therefore, we hypothesized that coating MTA with gallic acid (GA) would regulate physical properties and lead to enhanced adhesion, proliferation, and secretion of angiogenic- and odontogenic-related proteins. This study examined whether MTA can be modified with GA to form GAMTA cement and evaluated its physicochemical and biological behaviors and immune suppression, angiogenesis, and odontogenesis capabilities. We soaked MTA in Tris buffer containing different concentrations of GA to coat the MTA powders. X-ray diffraction (XRD) and diametral tensile strength analyses were conducted to assess the physical characteristics of GAMTA. Then, we immersed GAMTA cement in simulated body fluid to evaluate its hydroxyapatite precipitation capabilities and silicon ion release profile. We used human dental pulp stem cells to assess the cell responses and the immunosuppressive, angiogenic, and odontogenic capabilities of GAMTA. The XRD results showed that GA was successfully coated onto MTA without the disruption or loss of MTA’s advantageous original structural properties. GAMTA demonstrated excellent physicochemical and biological properties, improving hydroxyapatite formation and angiogenic, odontogenic, and anti-inflammatory properties compared with MTA alone. Our results indicate that the GAMTA cement is a useful dental material for future tissue engineering and clinical applications.

Carbon nanotube reinforced nanohybrid urea-hydroxyapatite fertilizer for an improved nutrients utilization efficiency and reducing environmental pollution

An upgraded technology is needed in the agricultural sector in order to adopt sustainable practice to maintain high yield as well as reducing environmental pollution due to ammonia emissions attributed to mineral nitrogen fertilization. This study reports a modified urea-hydroxyapatite nanohybrids fertilizers incorporated with carbon nanotube for more efficient sustainable nutrients utilization and reduction of ammonia emissions from fertilizers application. The urea-hydroxyapatite fertilizer was mixed with carbon nanotube at varying ratio by mass percentage (Sample A = 1:0.5. B = 1:1, C = 1:2, and D = 1:3) using simple liquid immersion method. The assessment of all the samples and the control specimen (sample E) was conducted by subjecting them to the analysis of thermogravimetric at intervals of 20 min to 200 min, to determine their nitrogen release behaviour activities. The morphological properties of urea-hydroxyapatite fertilizer with and without carbon nanotubes were compared using spectroscopic analysis (SEM, FTIR and XRD). The mechanical tests were conducted to examine the tensile and compressive strengths of the urea-hydroxyapatite fertilizer with carbon nanotubes using diametral tensile strength technique. The data obtained reveals that the control sample (urea-hydroxyapatite fertilizer) released 70 to 80 % urea within first 50minutes while the samples with carbon nanotubes retained urea for longer and 76 to 90 % amount of nitrogen release was recorded in the first 150minutes. It is revealed that the sample C with mixing ratio 1:2 exhibited best slow-release nitrogen properties. The sample C displayed a moderately large amount of nitrogen in form of urea in the initial phase and followed by slow-release even until the last minutes (200minutes). In the contrary, urea-hydroxyapatite fertilizer (control sample) which released heavily in the initial phase followed by the release of low and non-uniform quantities until its last drop towards 150minutes. SEM result demonstrated that chemical reaction occurred between urea-hydroxyapatites particles and carbon nanotubes. XRD patterns of urea-hydroxyapatites nanohybrid structures with carbon nanotubes demonstrate that the samples show the hydroxyapatite properties with monocrystalline structure. It is confirmed from the FTIR spectra that chemical functionalization cropped up between urea-hydroxyapatites nanohybrid and carbon nanotubes particles. A remarkable increase in the mechanical strength (150 % for the tensile strength and 100 % for the compressive strength) of the sample C structures confirms that introduction of carbon nanotubes improved its strength properties for the purpose of prolong stability while discharging its role as a nutrients slow-release fertilizer. Thus, the designed nano-fertilizer formulation of sample C mixing ratio can therefore be used as alternative way of improving the nutrients usage efficiency for the plants growth as well as to reduce the ammonia emission to the environment as pollutant.

Assessment of the Effects of Boron Nitride Nanoplatelets Reinforcement on the Physical and Mechanical Properties of the Geopolymer Prepared by Natural Kaolinite: An In Vitro Study

Introduction: We aimed to assess the effects of the addition of boron nitride nanoplatelets on the physical and mechanical properties of the geopolymer prepared by natural kaolinite. Methods: The compressive strength and diametral tensile strength tests were conducted according to BS 1881-116:1983 and ASTM E9-89a(2000) using an atomic force max instrument. The surface microhardness of the geopolymer was evaluated using a Digital Vickers microhardness tester, following the guidelines outlined in ASTM E92-82(2003). The contact angle (wettability) tests were carried out according to ASTM D7334-08(2022). Results: There were statistically significant differences among all study groups regarding compressive strength, diametral tensile strength, surface hardness, and wettability (p &lt; 0.001). Conclusion: The boron nitride nanoplatelets reinforcement has a significant impact on the compressive strength, diametral tensile strength, surface microhardness, and wettability of the geopolymer, providing valuable insights for future research and development in this field.

Comparative Evaluation of Sorption, Solubility, Compressive Strength and Diametral Tensile Strength of Zirconomer Improved (ZI) with GIC – An In Vitro Study

Objectives To evaluate and compare the compressive strength CS diametral tensile strength DTS sorption and solubility of Zirconomer Improved ZI with GIC type IX.Methods This is an experimental in vitro study. Forty specimens of ZI and GIC type IX 20 each were prepared using a Teflon mould and were stored at 37ordmC for one hour. These specimens were then subjected to CS DTS sorption and solubility testing. Results were then analysed using One way analysis of variance ANOVA.Results CS and DTS were significantly higher for ZI compared to GIC type IX. Sorption and solubility values were lesser for ZI compared to GIC type IX. Conclusion The study concluded that ZI cement is a useful dental material that can be used to restore stress-bearing areas due to its increased strength low solubility and sorption rates. As a restorative cement for stress-bearing areas zirconia-reinforced GIC has considerable promise for usage in dentistry. This is due to its considerable strength as well as poor solubility and sorption rates.