Cylinder Mold Research Articles

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.

Effect of the Application Procedure on The Bond Strength of Universal Adhesive in Restoration Repair

Objective: This study aimed to evaluate the effect of reduced application time on the bond strength of a universal adhesive used for the repair of hybrid ceramic and composite resin restorations. Methods: In the study, a total of 48 rectangular prisms of sizes 7×6×2 mm hybrid ceramic (Vita Enamic, Zahnfabrik, Germany) and composite resin (Solare X, GC, Japan) specimens were prepared. All samples were aged with 5000 thermal cycles. Then, the upper surfaces of the samples were roughened with a diamond fissure bur (10–36µ, 852 FG Meisinger; Hager & Meisinger GmbH, Germany) with 5 strokes under water cooling. The samples were divided into 2 subgroups according to the different application times of the adhesive system (G-Premio Bond, GC, Japan) (n=12). Then, composite resin (Solare X, GC) was placed using plastic cylinder molds with 3 mm inner diameter and height and cured with light for 20 seconds. All samples were thermal aged and then a shear bond strength test was conducted. The data were analyzed with Two-way ANOVA and post-hoc Tukey HSD tests (p˂0,05). Results: Two-way ANOVA revealed that the repair bond strength of the 10 seconds of waiting was significantly higher than the quick application for both hybrid ceramic and composite resin (p˂0,05). It was determined that there was no significant difference between hybrid ceramic and composite resin in the both quick application group and 10 seconds waiting group (p˃0,05). Conclusion: Quick application procedure showed lower shear bond strength than 10 seconds waiting group for the repair of both composite resin and hybrid ceramic (p<0,05). Keywords: Quick application, Application time, Universal adhesive, restoration repair..

Functional liquid-infused PDMS sponge-based catheter with antithrombosis, antibacteria, and anti-inflammatory properties

A functional liquid-infused catheter surface strategy has recently attracted increasing attention for blood transport with the remarkable antibiofouling performance. Nevertheless, constructing porous structure inside a catheter with effective functional liquid-locking ability remains extremely challenging. Herein, the central cylinder mold and sodium chloride particle templates technique was used to create a PDMS sponge-based catheter that stores a stable functional liquid. Our multifunctional liquid-infused PDMS sponge-based catheter can not only exhibit bacterial resistant, less macrophages infiltration, a slighter inflammation response, but also capability to prevent platelet adhesion and activation, and impressively reduce thrombosis in vivo even at high shear. Therefore, these desirable properties will endow the prospective practical applications and serve as a watershed moment in the development of biomedical devices.

Experimental Investigation of Recycled Aggregate Concrete Including Metakoline

As construction is increasing day by day in last decade, it is concerned for processing of waste material with the help of recent technology. The current study investigated the effect of metakoline (MK) on mechanical properties of RAC. The current study presents the experimental results of Recycled aggregate (RA) with different percentage 0, 20, 40, 60, 80, 100% in concrete replaced by natural coarse aggregate. Casting of cube, beam, cylinder mould has been done. In addition to this replacement of cement partially with MK also has been introduced. The flexural strength, compressive tensile strength and split tensile strength of M-30 and M-25 have been determined and also there design mix has been prepared. The results show good effect up to 60% aggregate replacement but on further increases the replacement ratio of aggregate, strength decreases. Therefore sustainable concrete may be produced to make environment safe and eco-friendly.

Lem Beton Pengaruh Penggunan Lem Beton Pada Sambungan Pengecoran Antara Beton Lama dan Baru

In carrying out concrete work, if the casting work is not completed, then the casting must be stopped at places that do not endanger the construction according to the instructions of experts in accordance with the plan drawings. Casting of joints between old and new concrete with an overview of inclination angles of 0⁰, 45⁰, and 90⁰. Joints are part of the concrete construction to provide a safe stop for the casting for the stage of construction. The casting is carried out in several steps, in the first step filling the concrete in the cylinder mold up to half of the total, after the concrete has reached the age of 7 days, then the next concrete as connection concrete fills half of the old concrete by coating the old concrete connection using glue which is a mixture of additon addibond glue + water and without concrete only a mixture of cement + water. This research was conducted so that the implementation in the field knows the function of each slope angle at 0⁰ is used in casting column connections, 45⁰ is carried out on casting plate and beam connections, and 90⁰ is carried out on casting pile cap foundation connections. The test results of the compressive strenght & split tensile strength of concrete showed that the variation of the joint slope using glue was greater than the variation of the connection without. For the results of the greatest compressive strength test in intact concrete with an average strength value of 35,29 Mpa, while in the split tensile strength test the concrete got an average strength value of 2,37 Mpa.

Generalized models of slump and spread in combination for higher precision in yield stress determination

The cone slump test is a simple alternative for on-site measure of yield stress, and on this principle, cylinder mold is employed owing to its easy accessibility. As an extension of the previous investigation which has validated the cone's cylinder-like behavior in the slump geometry, this work adopted an equivalent cylinder to facilitate comparison in the spread geometry, together with cylinders of various dimensions to explore dimensionless spread to yield stress relation. Good consistency was observed in both slump profiles and spread contours between the mini cone and its equivalent cylinder. The spread diameters after normalization displayed a definite common correlation with dimensionless yield stress. After integrating the corrective coefficient β, the models of slump and spread were generalized to both cylinder and cone molds with desired accuracy, alleviating the overall deviation of 14.88 % by individual slump height to 10.25 % combining with spread and enhancing the robustness of predicted values.

Coaxial Embedded Printing of Gelatin Methacryloyl–alginate Double Network Hydrogel for Multilayer Vascular Tubes

The reconstruction of vascular-like tissues exhibiting a typical three-layer structure in vitro is vital to bio-fabrication research. It enables the realization of more complicated micro-environments, such as myocardium, liver, and tumor, which enables us to investigate their specific physiological phenomena or pathological mechanisms. Herein, we propose a coaxial embedded printing method, where the gelatin methacrylate (GelMA)–alginate composite hydrogel and sacrificial materials are extruded from a coaxial nozzle into a cylinder mold. By applying this method, we achieve the rapid fabrication of multilayer tube structures with inner diameters ranging from 400 to 1000 µm. In addition, myoblasts are encapsulated in the hydrogel, and the cells show high viability. Moreover, we encapsulate smooth muscle cells (SMCs) and the human umbilical vein endothelial cells–T1 (HUVEC-T1) cell line in the hydrogel to form vascular-like tissues, and the cells exhibit good morphology and protein expression. These results suggest that a vascular tube fabricated using the proposed method can serve as a vascular model for in vitro studies.

Chemical, mineralogical and thermal characterization of a composite alkali-activated binder based on coal gangue and fly ash

In recent years, alkali-activated binders, including materials called “geopolymers” (low calcium alkali-activated materials), have received great attention as a promising green building material while reusing a significant amount of industrial waste byproducts. This study presents preliminary results of an ongoing research project to produce lightweight alkali-activated binder based mortar using two Moroccan locally waste materials coal gangue and fly ash as aluminosilicate sources. The heavy metals (Cd, Cu, Ni, Pb and Zn) included in the coal gangue pose an environmental problem. These harmful heavy metals can be released by leaching coal gangue into water and soil. However, when coal gangue is used in an alkali-activated binder in concrete, these elements can become immobilized in the concrete and subsequently have a potentially positive impact on the environment and health. The raw materials used in the mortar mixture in this study were as follows: coal gangue, fly ash, lime, sand and gypsum. Sodium hydroxide solution (5 M) was used as an alkali activator in the mixture, which was placed into a cylinder mold and cured at room temperature. Then, the product obtained was tested by X-Ray diffraction (XRD), infrared (FTIR) and thermogravimetric analysis (TG-DTA).

Large-area transparent biocomposite films based on nanocellulose and nanochitin via horizontal centrifugal casting

In this study, we introduce the horizontal centrifugal casting (HCC) process that enables centrifugal force-assisted, scalable production of large-area (10 in.) polymer composite films based on nanocellulose (CNF) and nanochitin (ChNF). The HCC employs a cylinder mold with its rotation pivot being in a horizontal posture to harness centrifugal force to help flatten the film being cast, from which polymer composite films with excellent uniformity and flatness can be reliably produced in the size of the lateral surface of the cylinder mold. The combination of centrifugal force and horizontal layout of cylinder mold can allow reliable fabrication of large-area self-standing films from both polymeric solution and/or suspension in a scalable and simple fashion, which is a task not readily achieved in common film-forming techniques, such as solvent casting and vacuum filtration. We demonstrate such reliability and versatility of the HCC process by fabricating typical biocomposite films out of both a solution blend of ChNF/silk fibroin and a colloidal suspension of CNF/nanoclay as well as investigating their processing-structure-property relation as an optically transparent composite film targeting for structural component for flexible green optoelectronics and fire-retardant film, respectively.

Correlating the Durability Properties of Roller Compacted Concrete

Roller compacted concrete is the zero-slump concrete mixture, usually prepared at low cement content and low workability, and subjected to compaction by rollers to increase the density and improve the aggregate particles interlock. It is recommended for heavy duty pavement and can withstand harsh environment. Modeling the physical behavior of roller compacted concrete exhibits a quick and easy start to predict the future behavior of the material. In the present assessment, roller compacted concrete mixtures have been prepared in the laboratory using three percentages of Portland cement (10, 12, and 16) % to simulate low, medium, and high cement content from roller compacted concrete point of view. The mixtures were poured into the cylinder mold of 101.6 mm diameter and 116.4 mm height in five successive layers. Each layer had practiced 25 blows of the modified Proctor hammer with 4.5 kg weight, falling from 450 mm height. Specimens were withdrawn from the mold after 24 hours and cured for 28 days in a water bath at 20°C. Specimens were subjected to bulk density, absorption, and porosity determination. Test results were analyzed and modeled. It can be observed that the gradation of aggregates (dense or gap)does not exhibit a significant issue in the absorption-density relationship. However, Dense gradation exhibits lower porosity than gap gradation. It can be concluded that the obtained mathematical models may be implemented to predict the relationship between the durability parameters of roller compacted concrete in terms of porosity, absorption, and density with high coefficients of determination.

Effect of Zeolite to Clay Ratios on the Formation of Zeolite-Clay-White Cement Composite Cylinder as an Encapsulant of Urea Fertilizer

Zeolite-clay-white cement composite cylinders have been prepared for the encapsulant of urea powder. The composites were made by mixing natural zeolite, clay, and white cement at certain ratios using a home-made cylinder mold. All processes were done at room temperature. The composites were characterized using infrared (IR) spectroscopy and X-ray diffraction (XRD). Mechanical properties of the composites were evaluated through compressive strength and water absorption capacity test. The infrared spectra showed functional groups at 3448 and 1636 cm–1, indicating the presence of calcium silicate hydrate as the main product of hydration and pozzolanic reactions in the composite. The XRD patterns also confirmed the presence of calcium silicate hydrate as tobermorite (d = 3.34, 3.22, 2.75, and 2.28 Å) and jennite (d = 4.50 Å). Increasing the natural zeolite ratio in the composite decreased the compressive strength but increased water absorption capacity. The composite cylinders are envisaged as the encapsulant of urea powder and act as a slow-release fertilizer.

Study the effect of casting temperature on details from thermo-plastic materials

The implementation of plastic details in various constructions enables to reduce the prime cost and labor intensity of machine and device manufacturing, decrease the weight of design and improve their quality and reliability at the same time. The studies were carried out with the aim of labor productivity increase and substitution of colored and black metals with plastic masses. For this purpose, the details with certain characteristics were selected for further implementation of developed technological process in oil-gas industry. The paper investigates the impact of cylinder and compression mold temperature on the quality parameters (shrinkage and hardness) of plastic details in oil-field equipment. The accessible boundaries of quality indicators of the details operated in the equipment of exploration, drilling and exploitation of oil and gas industry are studied in a wide range of mode parameters. The mathematic dependences between quality parameters (shrinkage and hardness) of the details on casting temperature are specified.

The Mechanical Performance of Pipe Based on Fiberglass Reinforced with Plastic Waste (FRPW) Composites

The project research present the mechanical performance of pipe based on fiberglass reinforced with plastic waste (FRPW) in plant application system. The use of FRPW able to reduce corrosion problem faced by oil and gas industry. In this study involved four types of combination ratio of fiberglass reinforced with plastic waste (FRPW) of 1.0: 0.5; 1.0:1.0; 1.0:1.5; and 1.0:2.0. The fabrication process started with grinding process of plastic waste into small size in the range of 0.1 mm. Fiberglass then reinforced with plastic waste by mixed with resin and hardener with ratio of 2: 1 and poured into the cylinder mould. There is a possibility fiberglass from 10-40% by weight result in substantial increase in elastic modulus, accompanied by an increase in strength with reduced ductility 1.0 of ratio. The tensile test showed clearly exhibited that 1.0 of plastic waste reinforced fiberglass with stand the higher maximum force value of 2.69 kN. For the bending test ratio of 1.0 of plastic waste withstand the higher bending strength at 5.29 kN. Ratio of 1.0 FRPW is more suitable for produced pipe in plant application system due to matrix-reinforcement bonding for each pipe sample after conducting tensile strength. The result obtained that ratio 1.0 of FRPW shown good matrix-reinforcement bonding.

The effect of repeated preheating on diametral tensile strength of composite resin with different fillers

Background: The development of adhesive systems has made the removal of carious lesion a minimally invasive procedure. Composite resin is the material of choice today, but the filler composition of the resin varies. Packable composite resin has good mechanical properties, but its high viscosity makes it hard to manipulate. Several methods, such as preheating, are used to decrease this viscosity. A syringe of composite resin might be preheated several times, but the effect of repeated preheating is unknown. Objectives: The purpose of this research was to analyze the effect of repeated preheating on the mechanical properties of a composite resin with different fillers. Method: Microhybrid, nanohybrid, and nanofill composite resins were preheated (ten times, twenty times, and control), molded into cylinder molds 6 mm in diameter and 3 mm in height, flattened with a celluloid strip, and polymerized with an light-emitting diode light-curing unit for 40 s. A total of 180 specimens were tested. The specimens were divided into two groups: Group 1 was immediately tested using a universal testing machine. Group 2 was soaked in 37°C artificial saliva for 24 h before testing. Each specimen was tested using the universal testing machine with the pressure side with a 1 mm/s crosshead speed. Result: Nanohybrid composite resin had the most stable diametral tensile strength after repeated preheating, whereas nanofill composite had the weakest strength. The increase and decrease in the diametral tensile strength in each group were not statistically significant. Conclusion: Repeated preheating does not significantly affect the diametral tensile strength of composite resin.

Making Print Tool Gambir Sap Parallel Slinder System

The problems that exist in the former group are the process of knowing the results of processing gambir sap is still done manually. To print 20 kg of gambier sap, it takes about 5 to 8 hours. Through this service activity, the team wanted to overcome the problem by providing a sap gambir. The purpose of implementing this service activity is to provide a solution to the problems faced by gambier farmers in the process of printing sap gambir. The method of applying science and technology carried out in this activity is to provide introductory theories, demonstrations, and practices. The introductory theory is applicable, namely the introduction of tools, how to use them, their functions and application applications in the field. The realization of the service to the community of Kenagarian Lampanjang Sutera Pesisir Selatan Subdistrict was held on October 6, 2018. The tool that was handed over to the community of Kenagarian Lampanjang Kecamatan Sutera was a unit of a parallel cylinder printer. Application of appropriate technology that is applied to processing gambir leaves must be adjusted to the productivity of printed sap gambir. The amount of gambir sap obtained by gambir farmers will adjust the capacity of the gambir sap. The tool devoted to the community has cylindrical media made with wood media with a thickness of 70 m. The mould cylinder will print the sap of gambir according to the size sold on the market and have a gum pushing media from the mould which serves to release the sap that is in the cylinder mould. This driving media is also made using wood.

Effect of different ratio of geopolymer paste based fly ash-metakaolin on compressive strength and water absorption

This paper presents the effect of different solid to solid (S/S) ratio by mixing the fly ash and metakaolin as geopolymer paste on the compressive strength and water absorption. Fly ash is a waste materials produced by combustion of coal at power plant while metakaolin was obtained by calcining the kaolin at 750 °C for 4 hours. Different weight percentage of S/S ratio of fly ash/metakaolin used were 50%:50% (Mix 1), 70%:30% (Mix 2) and 90%:10% (Mix 3). Alkaline activators that act as binder were sodium hydroxide (NaOH) and sodium silicate (Na2SiO3) solutions. The ratio of Na2SiO3/NaOH is 2.5 to 1. The mixture then placed into cylinder mould and left for 7, 14 and 28 days before it be tested. The product obtained were observed and it shows that Mix 2 has highest compressive strength for 28 days that was 41.22 MPa and has lower water absorption. The pore size decreases and permeability also decreases hence the strength potentially improve.

Use of Weight Maturity Method for Building Concretes Used in Artvin Yusufeli Dam Construction

The aim of this study is to compare the compressive strength determined by weight maturity method in dam concretes with compressive strength obtained from fresh concrete and core samples. Within the scope of the study, normal concretes of C25/30 strength class were produced. Samples were taken from ø15x30 cm cylinder molds from normal concrete mixtures having maximum aggregate grain diameter (Dmax) of 25 mm.In this study, the estimated compressive strengths were measured by using a maturity device and the compressive strengths obtained from samples taken from fresh concrete and core samples taken from hardened concrete were measured at close values. In this context, instead of taking samples from fresh concrete and concrete productions, it was concluded that the pressure resistance measurements made by using a maturity device in fresh concrete are reliable.

SINTESIS DAN KARAKTERISASI GEOPOLIMER BERBAHAN DASAR KAOLIN CAPKALA DENGAN VARIASI RASIO MOL SiO2/Al2O3

One of the potential raw materials for the preparation of geopolymers is kaolin. In the present report, the used activated kaolin is from Capkala Village in West Borneo. This paper presents an experimental study on the influence of different SiO2/Al2O3 molar ratios on the compressive strength and microstructural characteristics of the Capkala kaolin-based geopolymer. The used Capkala kaolin was a product of the calcination of the source material at 750ºC 2 h. The alkaline activator solutions that were used to activate the activated capkala kaolin precursor were prepared by mixing NaOH solution with Na2SiO3 solution. The activator solution was allowed to equilibrate for a minimum of 24 h at a room temperature before use. The geopolymer was prepared by hand mixing of the Capkala kaolin and the activator solution. Experiments conducted with SiO2/Al2O3 molar ratios of 3.8; 3.9; 4.0; 4.1 and 4.2 for all mixing. The resulting pastes are cast in cylinder molds of 2.3 × 4.6 cm. The pastes hardened 24 h in the forms, at room temperature for 24 h. The geopolymer was dried at 60ºC 2 h. The geopolymer was tested for compressive strength and sample pieces were taken from ones with the highest strength for XRD and SEM. Based on the test was obtained that geopolymer with 3.9 SiO2/Al2O3 ratios has the highest compressive strength that is 2.820 Mpa. The XRD analysis showed the peak at 2θ(º) 26,69o, 20,92o dan 19,77 o. The spectra FTIR of geopolymer showed the absorption at 3289.96 cm-1; 1647.67 cm-1 and 955.65 cm-1. Moreover, there are functional groups absorption for geopolymer such Al-OH stretch vibration (near 900 cm-1), stretch vibration of Si-O and Al-O (600-700 cm-1), Si-O-Al bend vibration (near 500 cm-1). The morphology of the capkala kaolin based geopolymer with SEM has succeeded in changing the kaolin structures in the form of regular slabs to be more irregular due to heating with a temperature of 750ºC.

Peningkatan Kuat Tekan dan Kuat Lentur Beton Dengan Variasi Penambahan Serat Daun Nanas

Beton merupakan bahan bangunan yang banyak dipergunakan, dikarenakan bahan ini kuat terhadap tekan dapat dengan mudah dibentuk menyesuaikan dengan kebutuhan. Di sisi lain beton mempunyai kelemahan terhadap lentur serta mempunyai sifat getas, sehingga diperlukan metode untuk memperbaiki kelemahan tersebut. Salah satu upaya untuk meningkatkan kuat tarik beton dilakukan dengan penambahan serat, sehingga menjadi suatu bahan komposit yaitu beton dan serat. Penelitian ini bertujuan untuk meningkatkan kuat tekan dan kuat lentur beton dengan variasi penambahan serat sebesar 0%, 1%, 3%, 5%, dan 7% terhadap berat semen pada mutu beton K-225. Perancangan beton menggunakan metode Department of Environment (DOE), dengan cetakan silinder berukuran 150 mm x 300 mm Jumlah sampel pada setiap penambahan serat sebanyak 3 sampel dan total sebanyak 30 sampel. Hasil pengujian menunjukkan nilai kekuatan tekan dan lentur beton tertinggi untuk variasi dengan tambahan serat daun nanas sebesar 5 % dengan nilai kuat tekan rata-rata 267,00 kg/cm2 dan nilai kuat lentur rata-rata 41,61 kg/cm2.

Evaluation of Dual-Cure Resin Cement Polymerization under Different Types and Thicknesses of Monolithic Zirconia.

Purpose The aim of the present study was to investigate the effects of the type and thickness of the zirconia material on the microhardness of the underlying dual-cure resin cement. Materials and Methods Eight disk-shaped zirconia specimens with a 4-mm diameter and four varying thicknesses (0.5, 1.0, 1.5, and 2.0 mm) were fabricated from two different monolithic zirconia materials: posterior monolithic zirconia (Prettau) and anterior monolithic zirconia (Prettau Anterior). Dual-cure resin cement specimens with a 4-mm diameter and 5-mm height were prepared using Teflon cylinder molds and activated by light beneath the eight zirconia disks and without any zirconia disk for 20 s (n=12). A total of 108 specimens were embedded in acrylic. Vickers hardness of each specimen was measured at three different depths using a microhardness device with a 50-g load. All data were statistically evaluated using three-way ANOVA, one-way ANOVA, independent samples t-tests, and Bonferroni corrected post hoc tests (α=.05). Results Dual-cure resin cement's microhardness was significantly higher for the samples polymerized beneath anterior monolithic zirconia compared to posterior monolithic zirconia. The hardness decreased as the thickness increased for both types of zirconia; the latter was attributed to an attenuated curing efficiency. Conclusion Microhardness of the dual-cure resin cement is influenced by both the type and the thickness of the monolithic zirconia restoration. Polymerization efficiency for resin cement cured under anterior monolithic zirconia may be superior to cured beneath posterior monolithic zirconia.