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Background: Class II restoration according to the classification of Greene Vardiman Black is one of the procedures in dental conservation that often presents a challenge for operators or dentists during treatment. Class II restorations have their own level of difficulty, particularly during the placement of restorative materials into the cavity. One of the possible failures in Class II restorative treatment is marginal leakage, which can lead to microleakage at the restoration margins. Purpose: To report the success of class II restoration with composite resin using tofflmire matrix. Case report: A 23-year-old female patient came with a complaint of cavities, the complaint was felt since 1 year ago in the lower left back tooth, there was no pain and had never been treated. In the case, preparation and restoration were carried out using composite resin with isolation using tofflmire matrix, applied using an Incremental technique. Discussion: Class II posterior tooth restorations have challenges such as leakage due to the techniques and materials used. Composite resin is chosen because of its good adaptation, esthetics, and wear resistance. Incremental techniques are preferred because they reduce polymerization stress and provide optimal curing results. Tofflemire matrix is ​​used for stability and soft tissue protection.Conclusion: The selection of composite resin with an Incremental technique and the use of a Tofflemire matrix provides more optimal, aesthetic, and minimal risk of failure results for class II posterior tooth restorations.

Natural fiber based composite materials are increasingly being developed as an environmentally friendly alternative to synthetic fiber-based composites. This study aims to characterize the thermal and mechanical properties of natural fiber composite materials and evaluate their potential use as sustainable materials. Composites are made using natural fibers as reinforcement and a polymer matrix through a specific molding method. Mechanical property characterization includes tensile tests, flexural tests, and impact tests, while thermal property characterization is carried out using thermal analysis to determine the thermal stability of the material. The test results show that the addition of natural fibers has a significant effect on improving the mechanical properties of the composite, especially tensile strength and elastic modulus, compared to the unreinforced matrix. In addition, natural fiber composites show quite good thermal stability over a certain temperature range, making them suitable for non-structural applications. Based on these results, natural fiber composite materials have the potential to be developed as environmentally friendly materials that have competitive mechanical and thermal performance.

The increasing need for insulation in electric power systems encourages the discovery of high-performance and sustainable dielectric materials. This study presents a Literature Review of biomass-based composite insulator research from 2018-2025 to synthesize the effect of filler type and treatment on the electrical, thermal, and mechanical properties of polymer composites. Literature was analyzed from reputable databases with inclusion criteria, and thematic analysis data extraction. Processing methods generally include washing, acid/alkali treatment, calcination, and advanced production techniques such as sol-gel and ultrasonication, integration of biomass fillers especially at low fractions (3-7%). The results show 1) the dominance of the use of rice husk as a source of biosilica for the main matrix filler of the insulator. 2) the performance of biomass composite insulators is highly dependent on the quality of purification, particle size, and surface modification of the filler. 3) there is a significant increase in the insulator's breakdown strength, resistivity, and thermal stability with the addition of biomass fillers to the main matrix. 4) the long-term stability of biomass materials against humidity and thermal aging has not been evaluated in depth.  

Composite materials have the potential to be used as an alternative material for e-scooter frames due to their low weight and good mechanical strength. The mechanical properties of composite materials are strongly influenced by their constituent materials, particularly the fiber fraction. This study aims to analyze the effect of fiberglass composition variations on the tensile strength of composite materials as an alternative for e-scooter frames. The results show that increasing the fiberglass content leads to an improvement in the tensile strength of the composite material. The tensile strength increased by 51.52% when the fiberglass content was increased from 40% to 50%, while an increase of 19.5% was observed from 50% to 60%, indicating a decreasing rate of improvement. At higher fiberglass compositions, voids were observed due to imperfections in the manufacturing process, which affected the bonding between the fiber and the resin. In addition, increasing the fiberglass content resulted in a reduction in tensile strain from 1.1% at 40% fiberglass to 0.55% at 60% fiberglass, indicating that the material became stiffer and more brittle. These results indicate a trade-off between increased tensile strength and reduced ductility of the composite material.

Composite materials have the potential to be used as an alternative material for e-scooter frames due to their low weight and good mechanical strength. The mechanical properties of composite materials are strongly influenced by their constituent materials, particularly the fiber fraction. This study aims to analyze the effect of fiberglass composition variations on the tensile strength of composite materials as an alternative for e-scooter frames. The results show that increasing the fiberglass content leads to an improvement in the tensile strength of the composite material. The tensile strength increased by 51.52% when the fiberglass content was increased from 40% to 50%, while an increase of 19.5% was observed from 50% to 60%, indicating a decreasing rate of improvement. At higher fiberglass compositions, voids were observed due to imperfections in the manufacturing process, which affected the bonding between the fiber and the resin. In addition, increasing the fiberglass content resulted in a reduction in tensile strain from 1.1% at 40% fiberglass to 0.55% at 60% fiberglass, indicating that the material became stiffer and more brittle. These results indicate a trade-off between increased tensile strength and reduced ductility of the composite material.

Leaf springs serve as vehicle weight supports and vibration dampers from uneven roads. Reducing vehicle weight can support fuel consumption reduction. The use of composite materials allows for a reduction in leaf spring weight without reducing load capacity and stiffness. The purpose of this study was to find the composition of composite leaf springs with a polyurethane matrix that were resistant to tensile and flexural tests using e-glass, epoxy, and polyurethane materials. This study used an experimental method, in which specimens were tested using a tensile and flexural testing machine. The variations included polyurethane matrices of 10%, 20%, and 30%. The data was statistically analyzed using Excel to determine the significant effect of the variables. The results showed the effect of polyurethane variation on the composite. The tensile test showed that the greatest tensile stress was on the 30% polyurethane specimen at 1.574 N/mm² and the smallest was on the 10% specimen at 7.007 N/mm². In the flexural test, the greatest effect on flexural strength was observed in the 30% specimen at 14.36 MPa and the smallest in the 10% specimen at 25.82 MPa. Without the addition of polyurethane, the tensile stress was 39.678 N/mm² and the flexural strength was 157.09 MPa. Conclusion: The addition of polyurethane reduces the mechanical strength of composite leaf spring material without polyurethane addition.

Leaf springs serve as vehicle weight supports and vibration dampers from uneven roads. Reducing vehicle weight can support fuel consumption reduction. The use of composite materials allows for a reduction in leaf spring weight without reducing load capacity and stiffness. The purpose of this study was to find the composition of composite leaf springs with a polyurethane matrix that were resistant to tensile and flexural tests using e-glass, epoxy, and polyurethane materials. This study used an experimental method, in which specimens were tested using a tensile and flexural testing machine. The variations included polyurethane matrices of 10%, 20%, and 30%. The data was statistically analyzed using Excel to determine the significant effect of the variables. The results showed the effect of polyurethane variation on the composite. The tensile test showed that the greatest tensile stress was on the 30% polyurethane specimen at 1.574 N/mm² and the smallest was on the 10% specimen at 7.007 N/mm². In the flexural test, the greatest effect on flexural strength was observed in the 30% specimen at 14.36 MPa and the smallest in the 10% specimen at 25.82 MPa. Without the addition of polyurethane, the tensile stress was 39.678 N/mm² and the flexural strength was 157.09 MPa. Conclusion: The addition of polyurethane reduces the mechanical strength of composite leaf spring material without polyurethane addition.

This paper was made to explain the results of research on how to obtain the most appropriate citric acid adhesive composition in the manufacture of randu wood fiber composites in order to obtain a strong and suitable composite material. The research was carried out by experimental methods in the laboratory through a series of mechanical tests, namely the bending strength test and the screw grip strength test. The sample specimen is 5 cm × 20 cm × 1 cm for flexural strength testing and 5 cm × 10 cm × 1 cm for screw grip strength test. Composite specimens were made with variations in the composition of citric acid adhesives of 2.5%, 5%, 7.5%, 10%, 12.5%, 15%, 17.5%, and 20% by weight of randu wood. The results showed that the composite of randu wood particles with a citric acid matrix had optimal strength at a certain ratio, which was 7.5%. At the same ratio, the test results of the screw grip strength test also provide the highest value. These findings confirm that the exact composition of the adhesive has a significant impact on the final performance of the resulting composite.

This study aims to analyze the comparison of the durability of natural fiber and synthetic fiber composites in a high-temperature production environment. Testing was conducted on carbon fiber, aramid (synthetic), ramie, and jute (natural) fiber-based composites with exposure to temperatures of 80-150°C for 500 hours. The parameters measured include tensile strength, elastic modulus, dimensional stability, morphological changes, and moisture absorption. The research results show that synthetic fiber composites have superior durability compared to natural fibers. Carbon fiber composites retain 87% of their initial tensile strength with only a 4.2% reduction in modulus, while flax fibers only retain 62% strength with a 26% reduction in modulus. Microscopic analysis revealed significant delamination in natural fiber composites with interface gaps of 15-25 μm, compared to 3-5 μm in synthetic fibers. Natural fibers undergo thermal degradation due to the decomposition of lignin and hemicellulose, resulting in significant color changes and a dimensional shrinkage of 3.2%. The moisture absorption of natural fibers increases to 8.5% after exposure, indicating damage to the cellular structure. This research concludes that synthetic fiber composites are more suitable for long-term high-temperature production applications, but natural fibers can still be considered for low-temperature applications with appropriate chemical modification.

The problem with previous studies was the use of polyester resin as a matrix in kacang goat hair fiber composites, whereas in the latest study, epoxy resin was used, which has not been widely used. The aim was to obtain the tensile strength of composites that could be used as an alternative material for fan blades. The research method used was experimental with composite fabrication using the hand lay-up method, varying fiber lengths of 10 mm, 20 mm, and 30 mm, and varying immersion times in a 5% NaOH solution for 25, 50, 75, and 100 minutes. Tensile strength testing was carried out using the ASTM D638 standard with a total of 36 specimens. The test results showed that specimens with a fiber length of 30 mm and a soaking time of 50 minutes produced the highest tensile strength of 28.69 MPa, while the lowest tensile strength of 15.38 MPa was obtained in specimens with a fiber length of 10 mm and a soaking time of 100 minutes. This indicates that the highest tensile strength value is 46.37% greater than the lowest value, so the combination of a fiber length of 30 mm and a soaking time of 50 minutes is determined to be the optimal parameter in this study.

Indonesia is one of the countries with abundant availability of palm fiber composite, yet its application in advanced material technology remains limited. On the other hand, most motorcycle helmets available in the market are made from ABS plastic, which has limitations in impact energy absorption and may increase the risk of head injuries during accidents. This study aims to develop helmet composites based on palm fiber and epoxy resin by varying the fiber volume fractions (15%, 25%, and 35%) and alkali soaking durations (75, 150, 225, and 300 minutes). The impact strength test results showed that the combination of 35% fiber volume and 225-minute alkali soaking produced the highest specific impact energy (SIP) of 0.142 J/mm². As a comparison, SNI-compliant helmets made from ABS plastic only reached an EPS value of 0.00972 J/mm², indicating that palm fiber-based composite helmets could improve impact energy absorption efficiency by more than 14 times. The results conclude that increasing the fiber volume fraction and optimizing the alkali treatment duration significantly enhances the impact resistance, making ijuk-based composite helmets a promising alternative for safer and more eco-friendly protective gear.

This study aims to investigate how variations in the soaking time of Luffa cylindrica fibers in alkaline solutions affect the mechanical properties and fire resistance of the resulting composite material. The use of natural fibers is an important step in finding environmentally friendly and sustainable alternatives to replace synthetic materials. Luffa cylindrica fibers were chosen for their advantages, such as being lightweight, strong, and abundantly available. However, natural fibers like luffa contain non-cellulose compounds, such as lignin and hemicellulose, that can hinder strong bonding with the resin matrix. Therefore, pre-treatment with an alkaline solution is necessary to remove these interfering substances. In this study, composites were made using the hand lay-up method with polyester resin as the main matrix. The treatment variable tested was the fiber soaking time in KOH solution, with three variations: 2 hours, 4 hours, and 6 hours. After the composite fabrication, the samples were tested through several standard tests, including tensile tests to measure the material's strength under tension, impact tests to assess toughness, and burn rate tests to evaluate fire resistance. Additionally, macro and micro photo analysis (using SEM if possible) will be conducted to observe fracture characteristics and the quality of the fiber-resin bond. The expected outcome is that longer alkaline soaking will significantly improve tensile strength and toughness. Furthermore, longer soaking is also expected to improve fire resistance by forming a char layer, which acts as a thermal insulator, slowing heat transfer and reducing the rate of pyrolysis.

This study aims to determine the effect of varying hybrid composite volume fractions of luffa (Luffa cylindrica) fiber and fiberglass on the tensile strength of the material. The composite matrix used was polyester resin, while the reinforcements consisted of luffa fibers treated with 5% KOH alkaline solution to improve adhesion with the matrix, and fiberglass as an additional strengthening material. The composition variations applied in this research were 90%:5%:5%, 85%:7.5%:7.5%, and 80%:10%:10% (polyester resin : luffa fiber : fiberglass). The fabrication process was carried out using the hand lay-up method, which is widely used for producing layered composites, followed by tensile testing according to standard mechanical testing procedures to evaluate tensile strength and elongation. The results showed that the addition of luffa fiber and fiberglass fractions had a significant influence on the mechanical properties of the composites. The 80%:10%:10% variation demonstrated the highest tensile strength value of 13.65 MPa and the highest elongation of 0.0105%, indicating better mechanical performance compared to other variations. These findings confirm that the hybridization of natural luffa fiber and synthetic fiberglass can work synergistically to improve the tensile strength of the composite. However, higher fiber fractions should be considered carefully, as they may affect the homogeneity of the mixture and the quality of interfacial bonding. Further research is recommended to optimize volume fractions, enhance fiber surface treatments, and evaluate additional mechanical properties such as impact strength and hardness, in order to explore the potential of hybrid composites as eco-friendly materials with promising mechanical performance.

Penelitian ini membahas konsep pembentukan Batalyon Komposit Korps Marinir di Pulau Natuna Utara dalam rangka mendukung validasi organisasi Korps Marinir. Penelitian ini dilatarbelakangi oleh meningkatnya dinamika geopolitik di kawasan Laut Natuna Utara yang rawan pelanggaran batas wilayah oleh kapal asing, sehingga menuntut kehadiran satuan tempur yang lebih permanen dan siap siaga. Permasalahan utama yang diangkat adalah belum optimalnya peran Kompi Komposit Korps Marinir yang masih berstatus sebagai satuan tugas yang kerap melakukan rotasi terhadap satuannya, disertai kendala infrastruktur, logistik, dan jumlah personel. Untuk itu, penelitian ini menggunakan metode deskriptif kualitatif dengan pendekatan research and development model Borg and Gall, melalui studi pustaka, wawancara ahli, observasi, dan kuesioner. Analisis dilakukan terhadap struktur organisasi, kesiapan alutsista, serta efisiensi sistem operasi dalam mendukung validasi organisasi Korps Marinir. Hasil penelitian menunjukkan bahwa pembentukan Batalyon Komposit yang bersifat permanen sangat dibutuhkan untuk menjawab kebutuhan pertahanan strategis, mempercepat reaksi terhadap ancaman, serta mengefektifkan tugas pengamanan wilayah perbatasan. Penelitian ini bermanfaat secara teoritis untuk memperkuat doktrin pertahanan laut berbasis pulau-pulau terluar, dan secara praktis sebagai masukan bagi pimpinan TNI AL dalam merumuskan kebijakan validasi organisasi yang berkelanjutan dan berdaya guna tinggi.

This study aims to examine the effect of fiber orientation and volume fraction on the impact strength of sugarcane fiber–epoxy composites. Sugarcane fiber is considered a promising natural reinforcement material due to its lightweight, renewable nature, and environmental friendliness. Specimens were fabricated using the vacuum bagging method with fiber orientations of 0°, 60°, 90°, and random, and volume fractions of 5%, 10%, 15%, and 20%. Impact testing was conducted according to ASTM D6110-10 to determine absorbed energy and impact strength. The results show that both fiber orientation and volume fraction significantly influence impact strength. The highest impact strength was achieved with a 15% volume fraction and 0° fiber orientation, reaching 0.085 J/mm² or an absorbed energy of 8.5 Joules. In contrast, the lowest value was recorded at a 15% volume fraction with 90° fiber orientation, yielding 0.018 J/mm² or 1.8 Joules. The interaction between these variables also contributed significantly to enhancing material toughness. These findings highlight the importance of optimizing fiber orientation and volume fraction in designing natural fiber-based composites for lightweight structural applications

The processing of natural fibers as raw materials for paper has grown over the past few years. However, the use of composite paper as a printing substrate has several drawbacks. One of them is the low color reproduction quality of printed images on paper made from natural fibers, caused by the insufficient whiteness of the paper. This study aims to investigate the effect of titanium dioxide (TiO₂) addition on the color reproduction quality of composite paper based on sugarcane bagasse fiber. TiO₂ was varied at concentrations of 0%, 10%, and 20%. Printing process was carried out using an inkjet printer with standard CMYK and RGB color patches. After that, the printed results were measured using colorimeter with D65 illuminant. Color distribution analysis was processed using MATLAB software. The results showed that the addition of TiO₂ increased the whiteness of the paper, as indicated by the higher L* values. The color gamut visualization demonstrated that the gamut area expanded as the TiO₂ content increased. This result shows that the addition of TiO₂ affects the color reproduction quality of composite paper.

Natural fibers can be used as an alternative basic material for produce SNI helmet that are environmentally friendly. A huge potential of hemp fiber in Indonesia has not apply properly yet. This study propose to determine the ability of tensile strength and impact toughness in hemp fiber composites so that hemp fiber can be used as an alternative material for making SNI helmets. This study uses an unsaturated polyester 157 BQTN-EX resin matrix and MEKPO catalyst. Alkali treatment of the fibers uses 5% NaOH for 2 hours. The composite is made using the hand lay-up method. Variations volume fraction of hemp fiber used are 30%, 40%, 50%. The tensile testing process uses the ASTM D 638-03 standard and impact toughness testing uses the ASTM D 265-03 standard. Based on the research results, the highest tensile test results were obtained at variation on 30% fiber volume fraction is 18.30 MPa, for the highest impact toughness test results were obtained at variation on 50% fiber volume fraction is 0.0248 J/mm2. The greater the variation of the fiber volume fraction given, the lower the tensile strength value produced, while the higher the variation of the fiber volume fraction given, the greater the energy absorbed so that the impact price increases. Based on the test results, this hemp fiber composite needs to be considered as an alternative material to replace SNI helmet manufacturing.

The use of lightweight plastic materials is widely applied in the manufacturing of car dashboards. Lightweight plastics or polymers, such as ABS plastic, are not strong enough or can easily crack when impacted. Banana pseudostem fibers have good mechanical properties and are a potential reinforcement for composites. This study aims to analyze the tensile strength of unsaturated polyester-banana pseudostem fiber composites produced through the hand lay-up method at three different angles: 0°/90°, 15°/105°, and 30°/120°. The tensile testing refers to ASTM D638 standards. The results of the tensile tests show that the 0°/90° weaving angle variation had the highest tensile strength value, which was 372.07 MPa. The 30°/120° fiber orientation variation had the lowest tensile strength value at 198.12 MPa. The fractures from the tensile tests were observed through macro photos to understand the failure mode. The macro photo observations showed that all specimens experienced fiber pull-out.    

Purple yam is one of the tubers that serves as a source of antioxidants but has not been optimally utilized. Therefore, it needs to be diversified by processing it into snack bars. This study aims to develop snack bars made from purple yam flour, sorghum flour, and mung bean flour, which have the potential to serve as antioxidant sources and are preferred by panelists. In this study, snack bars were prepared using composite flour (sorghum:mung bean) and purple yam flour in varying ratios: 95:5, 90:10, 85:15 for the composite flour and 20%, 30%, and 40% for the purple yam flour. The snack bars were evaluated for color, texture, moisture content, antioxidant activity, and preference level. Selected samples were further analyzed for ash content, protein content, fat content, anthocyanin content, and crude fiber content. The experimental design used was a Completely Randomized Design (CRD) with two factors. The snack bars with a composite flour ratio (sorghum:mung bean) of 85:15 and 30% purple yam flour were identified as the best treatment, preferred by panelists and exhibite high antioxidant activity. These snack bars had a moisture content of 13.40%, ash content of 8.83% (db), protein content of 19.75% (db), fat content of 8.80% (db), crude fiber content of 9.54% (db), antioxidant activity of 68.02% (RSA), and anthocyanin content of 37.40 mg/100g

This research examines the potential of Epoxy-HGM-Carbon Fibre and Epoxy HGM Sical Woven Fibre composites as alternative materials for bulletproof vests. These two materials were chosen because they have similar ballistic protection capabilities to kevlar but with lighter weight and more economical cost. Using the finite element method, this study simulates the resistance of each composite to the penetration and impact energy of projectiles in accordance with the NIJ 0101.06 standard to protect users from ballistic threats. The simulation results show that the Epoxy-HGM-S Sisal Woven Fibre specimen at an optimum thickness of 30 mm as well as Epoxy-HGM-Carbon Fibre at a thickness of 18 to 30 mm are able to meet the penetration, Back Face Signature (BFS), and residual kinetic energy criteria that comply with the safe limits for users. This research makes an important contribution to the identification of alternative materials that not only improve user comfort and mobility, but also maintain ballistic protection effectiveness for military and security applications, especially for personnel who need protection against ballistic projectiles.