scholarly journals Study of local silica sand deposits for producing leucite glass-ceramics for dental applications

2014 ◽  
Vol 10 (4) ◽  
Author(s):  
Siti Mazatul Azwa Saiyed Mohd Nurddin ◽  
Malek Selamat
Keyword(s):  
Research Work ◽  
Testing Machine ◽  
Glass Ceramics ◽  
Raw Material ◽  
Silica Sand ◽  
Bending Test ◽  
Effect Of Temperature ◽  
Soaking Time ◽  
Dental Applications ◽  
Glass Powders

The objective of this research work was to examine the potential of using local silica sand from Terengganu, as a raw material in producing leucite glass-ceramics for dental applications.  The characterization of the silica sand was carried out using chemical analysis and X-ray fluorescence (XRF) analysis. The study also focused on the effect of temperature and soaking time of sintering on the formation and properties of leucite glass-ceramics for dental applications.  A starting glass composition of weight %; 64.2% SiO2, 16.1% Al2O3, 13.6% K2O, 5.10% Na2O, 0.5% TiO2 and 0.5% LiO2 was melted in an electric furnace, and then quenched in cool water to produce glass frit. The glass powders were ball milled and compressed to form 13mm diameter discs.  The discs were sintered at 700°C,750°C, 800°C and 850°C for 1.0, 3.0, 6.0, 9.0 and 12.0 hours. The XRD analysis results show that the glass powders produced leucite phase as the major phase at certain temperature and soaking time of sintering.   The sanidine (KAlSi3O8) phase was also formed as the minor phase.  The properties of sintered discs were studied using field emission scanning electron microscopy (FESEM), Vickers micro hardness and universal testing machine (UTM).  Based on the microhardness and three point bending test results,  the strength of the samples increased as the soaking time of sintering increased.________________________________________GRAPHICAL ABSTRACT

Microstructure, Mechanical Properties, and Electrical Resistivities of Mica Glass-Ceramics with Flake Phlogopite and Waste Glass

2014 ◽  
Vol 602-603 ◽  
pp. 640-643
Author(s):  
Yu Fei Chen ◽  
Yan Gai Liu ◽  
Xiao Wen Wu ◽  
Zhao Hui Huang ◽  
Ming Hao Fang
Keyword(s):  
High Speed ◽  
Sintering Temperature ◽  
Raw Materials ◽  
Glass Ceramics ◽  
Waste Glass ◽  
Raw Material ◽  
Bending Test ◽  
Electric Locomotive ◽  
Molding Process ◽  
Electrical Resistivities

Mica glass-ceramics can be applied in all kinds of electrical equipment, locomotive internal circuits in high-speed rail, ordinary electric locomotive and subway locomotive. In this study, mica glass-ceramics were prepared by sintering process using flake mica and waste glass as the main raw material with low cost. Different mica glass-ceramic samples were fabricated by changing the formula of raw materials, molding process and sintering temperature. X-ray diffraction, scanning electron microscopy, three-point bending test, and balanced-bridge technique were applied to investigate the phase, microstructure, mechanical and electrical resistivities of the samples, respectively. The results show that the optimum sintering temperature is 900 to 1000 °C holding for two hours, the desirable ratio is 70 wt% of mica powder while 30 wt% of glass powder. In that condition the sample could be less porosity, high flexural strength (63.3 MPa) and eligible electrical resistivity (0.4×1013 Ω·cm).

scholarly journals Utilization of rapid prototyping technology for the fabrication of an orthopedic shoe inserts for foot pain reprieve using thermo-softening viscoelastic polymers: A novel experimental approach

2020 ◽  
Vol 53 (3-4) ◽  
pp. 519-530
Author(s):  
Shubham Sharma ◽  
Jujhar Singh ◽  
Harish Kumar ◽  
Abhinav Sharma ◽  
Vivek Aggarwal ◽  
...  
Keyword(s):  
Rapid Prototyping ◽  
Thermoplastic Polyurethane ◽  
Research Work ◽  
Testing Machine ◽  
Three Dimensional ◽  
Hardness Test ◽  
Thermoplastic Elastomer ◽  
Bending Test ◽  
Foot Orthosis ◽  
Orthotic Insoles

This research work has been completed by concentrating on the structure of inserts for foot orthosis fabricated by utilizing rapid prototyping technology. Thermoplastic elastomer and thermoplastic polyurethane are the most commonly used materials that are being used in customized three-dimensional printed orthotic insoles, which are comfortable and prevent the user in many foot disorders. Thermo-softening viscoelastic polymers, explicitly Filaflex and Ninjaflex, have been printed by utilizing Flash Forge three-dimensional printers to evaluate the mechanical properties of specimens with alterations of the percentage rate fill-up design replicas. The results are compared on the basis of hardness test, flexural/bending test, and tensile test using Durometer and Universal Testing Machine (UTM). It has also been observed that the most significant effecting factor is infill density.

Nucleation, Crystallization and Characterization of Mica-Based Glass-Ceramics with Fluorapatite

2014 ◽  
Vol 936 ◽  
pp. 164-169 ◽  
Author(s):  
Jia Bai ◽  
Duangrudee Chaysuwan
Keyword(s):  
Glass Ceramics ◽  
X Ray Diffraction ◽  
Soaking Time ◽  
X Ray ◽  
Optimal Heat Treatment ◽  
Treatment Conditions ◽  
Quenched Glass ◽  
Dental Applications ◽  
Soaking Temperature

The glass system of SiO2-Al2O3-MgO-MgF2-SrCO3-CaCO3-CaF2-P2O5 was used to prepare machinable glass-ceramics for restorative dental applications. The aim of this study was to apply various heat treatments to produce mica-based glass-ceramics. Differential Thermal Analysis (DTA) was used to determine the optimal heat treatment conditions for nucleation and growth of the crystalline phases in the quenched glass. It was found that the optimum nucleation temperatures for the first and the second crystallization temperatures (Tp1 and Tp2) were 642°C and 635°C, respectively, and the optimum nucleation times were between 2 and 4 hours. X-Ray Diffraction (XRD) showed the phases developed were anorthite, calcium-mica, fluorapatite, strontium apatite, forsterite, fluorite and stishovite phases. The microstructures of glass-ceramics were observed by Scanning electron microscope (SEM), found to exhibit plate-like mica crystals with high interlocking and randomly oriented with a higher soaking temperature and prolongation of the soaking time for crystallization.

scholarly journals The effect of temperature on cement clicker characterızatıon wıth a 10% substıtutıon of basalt stone on limestone mass

2020 ◽  
Vol 33 (01) ◽  
pp. 159-166
Author(s):  
Rajiman . ◽  
Muhammad Amin ◽  
Roniyus Marjunus ◽  
Agata Ani R. ◽  
David Candra B. ◽  
...  
Keyword(s):  
Raw Material ◽  
Silica Sand ◽  
Cement Clinker ◽  
Effect Of Temperature ◽  
Test Results ◽  
Orthorhombic Crystal ◽  
X Ray ◽  
Calcination Temperatures ◽  
Three Samples ◽  
Chemical Content

This research was conducted to determine the effect of temperature on the chemical content and crystal structure of the cement clinker with 10% substitution of basalt on the mass of limestone. The cement clinker is made from the composition of limestone, basalt stone, clay, silica stone and iron sand. Basalt stone used came from the East Lampung area. The basalt stone has fulfilled ASTM C618 standard with a total compound of SiO2 + Al2O3 + Fe2O3 of 79.2%. The raw material was then mixed, milled, formed into pellets with a size of 0.8 - 1.4 cm and continued with combustion at calcination temperatures of 1000 ℃, 1100 ℃ and 1200 with a holding time of 2 hours. Based on the results of the XRF test (X-Ray Fluorecence) of the three cement clinker samples with variations in temperature used, the sample is closer to the standard at a temperature of 1000 ℃. For the XRD (X-Ray Diffraction) test results, the three samples have tetragonal, monoclinic, rhombohedral, and orthorhombic crystal structures. As for the MO test results, there was a strong binding between iron sand, limestone, clay, and silica sand characterized by a smooth surface while basalt stones that look like black holes were not completely bound.

Crytallization and Properties of SiO2-Al2O3-K2O-ZrO2 Glass-Ceramics for Dental Applications

2014 ◽  
Vol 1024 ◽  
pp. 281-286 ◽  
Author(s):  
Siti Mazatul Azwa Saiyed Mohd Nurddin ◽  
Malek B. Selamat
Keyword(s):  
Glass Ceramics ◽  
Glass Frit ◽  
Silica Sand ◽  
X Ray Diffraction ◽  
Key Factors ◽  
X Ray ◽  
Three Point Bending ◽  
Glass Forming ◽  
Produce Glass ◽  
Dental Applications

The aim of the study was to investigate the influence of ZrO2 on the crystallization and properties of leucite phase from K2O -Al2O3- SiO2 glass-forming melts. A starting glass composition of weight %; 60.7-63.2% SiO2, 16.6% Al2O3, 11.6% K2O, 5.10% Na2O, 2.5-5.0% ZrO2, 0.5% TiO2 and 0.5% LiO2 was melted in an electric furnace, followed by quenched in cool water to produce glass frit. Malaysian silica sand from Terengganu was used as the SiO2 source. The glass powders were ball milled and compressed to form 13mm diameter discs using cool isostatic pressing. The discs were sintered at 650°C, 700°C, 750°C, 800°C and 850°C for 1 hour and characterised using X-ray diffraction (XRD) and field emission scanning electron microscope (FESEM). The results indicate that the amount of ZrO2 additive is one of the key factors controlling of leucite crystallization. The properties of sintered disc specimens were studied using three point bending, diametral and Vickers microhardness test. The results showed that the mechanical properties of leucite glass-ceramics increased as the amount of ZrO2 was increased.

Parametric Study of Damping Characteristics of Magneto-Rheological Damper: Mathematical and Experimental Approach

2020 ◽  
Vol 15 (3) ◽  
pp. 37-48
Author(s):  
Zubair Rashid Wani ◽  
Manzoor Ahmad Tantray
Keyword(s):  
Structural Control ◽  
Research Work ◽  
Testing Machine ◽  
Input Voltage ◽  
Damping Coefficient ◽  
Control Technique ◽  
Damping Force ◽  
Active Devices ◽  
Active Structural Control ◽  
Magneto Rheological

The present research work is a part of a project was a semi-active structural control technique using magneto-rheological damper has to be performed. Magneto-rheological dampers are an innovative class of semi-active devices that mesh well with the demands and constraints of seismic applications; this includes having very low power requirements and adaptability. A small stroke magneto-rheological damper was mathematically simulated and experimentally tested. The damper was subjected to periodic excitations of different amplitudes and frequencies at varying voltage. The damper was mathematically modeled using parametric Modified Bouc-Wen model of magneto-rheological damper in MATLAB/SIMULINK and the parameters of the model were set as per the prototype available. The variation of mechanical properties of magneto-rheological damper like damping coefficient and damping force with a change in amplitude, frequency and voltage were experimentally verified on INSTRON 8800 testing machine. It was observed that damping force produced by the damper depended on the frequency as well, in addition to the input voltage and amplitude of the excitation. While the damping coefficient (c) is independent of the frequency of excitation it varies with the amplitude of excitation and input voltage. The variation of the damping coefficient with amplitude and input voltage is linear and quadratic respectively. More ever the mathematical model simulated in MATLAB was in agreement with the experimental results obtained.

Pengaruh Penggunaan Batu Basalt Lampung dan Batubara dalam Bahan Baku terhadap Karakteristik Klinker

2020 ◽  
Vol 10 (1) ◽  
pp. 49
Author(s):  
Suharto Suharto ◽  
Muhammad Amin ◽  
Muhammad Al Muttaqii ◽  
Syafriadi Syafriadi ◽  
Kiki Nurwanti
Keyword(s):  
Experimental Study ◽  
Raw Materials ◽  
Coal Ash ◽  
Heating Time ◽  
Raw Material ◽  
Silica Sand ◽  
Cement Clinker ◽  
Duration Of Heating

Experimental study on the use of basalt stone originated from Lampung has been conducted to evaluate its potential for a partial substitute of raw material in production of cement clinker. The basalt stone contains minerals of anorthite, augite, and albite phases that are required for clinker formation. In this study, the main raw materials were 80% limestone, 10% silica sand, 9% clay and 1% iron sand. The raw material in these experiments were mixtures 90% or 80% of the main raw material and 10% or 20% of basalt stone. The effect of adding coal to raw materials was also studied to see the possibility of an increase in clinkerization temperature inside the raw material mixture, and at the same time to see the effect of coal ash on clinker composition. Clinker obtained from heating of raw materials at a temperature of 1100oC had LSF of 94.1% and 95.1% (heating time of 1 and 3 hours). If heating is carried out at 1200oC, the clinker had LSF of 97.7% and 98.0% (heating time of 2 and 3 hours, respectively). Depending on the temperature and duration of heating, the clinker mostly had SM in the range of 2.18-2.40% , and AM in the range of 0,78-1.80%. Characterization using XRD showed that the clinker consisted of larnite and gehlenite phases, and dominated by CaO.Batu basalt Lampung telah diuji potensinya sebagai pengganti sebagian bahan baku utama pembuatan klinker semen. Batu basalt tersebut memiliki mineral-mineral dalam fase anorthite, augite, dan albite yang diperlukan pada pembentukan klinker. Pada penelitian ini, bahan baku utama adalah batu kapur 80%, pasir silika 10%, tanah liat 9% dan pasir besi 1%. Campuran bahan baku klinker adalah 90% atau 80% bahan baku utama dan 10% atau 20% batu basalt. Efek penambahan batubara ke dalam bahan baku klinker juga dipelajari untuk melihat kemungkinan kenaikan temperatur klinkerisasi di dalam campuran bahan baku, dan sekaligus untuk melihat efek abu batubara terhadap komposisi klinker. Klinker hasil pemanasan bahan baku pada temperatur 1100oC memiliki LSF 94,1% dan 95,1% (lama pemanasan 1 dan 3 jam). Jika pemanasan dilakukan pada 1200oC, klinker memilik LSF 97,7% dan 98,00% (lama pemanasan 2 dan 3 jam). Tergantung pada temperatur dan lama pemanasan, klinker hasil percobaan ini umumnya memiliki SM 2,18-2,40%, dan AM antara 0,78-1,80%. Karakterisasi dengan XRD menunjukkan bahwa klinker terdiri dari fase larnite dan gehlenite, dan didominasi CaO.

scholarly journals Fracture Load of Metal, Zirconia and Polyetheretherketone Posterior CAD-CAM Milled Fixed Partial Denture Frameworks

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 959
Author(s):  
Verónica Rodríguez ◽  
Celia Tobar ◽  
Carlos López-Suárez ◽  
Jesús Peláez ◽  
María J. Suárez
Keyword(s):  
Computer Aided Design ◽  
Testing Machine ◽  
Fracture Load ◽  
Fracture Pattern ◽  
Bending Test ◽  
Weibull Statistics ◽  
Promising Alternative ◽  
Computer Aided ◽  
Cad Cam ◽  
Group 2

The aim of this study was to investigate the load to fracture and fracture pattern of prosthetic frameworks for tooth-supported fixed partial dentures (FPDs) fabricated with different subtractive computer-aided design and computer-aided manufacturing (CAD-CAM) materials. Materials and Methods: Thirty standardized specimens with two abutments were fabricated to receive three-unit posterior FDP frameworks with an intermediate pontic. Specimens were randomly divided into three groups (n = 10 each) according to the material: group 1 (MM)—milled metal; group 2 (L)—zirconia; and group 3 (P)—Polyetheretherketone (PEEK). The specimens were thermo-cycled and subjected to a three-point bending test until fracture using a universal testing machine (cross-head speed: 1 mm/min). Axial compressive loads were applied at the central fossa of the pontics. Data analysis was made using one-way analysis of variance, Tamhane post hoc test, and Weibull statistics (α = 0.05). Results: Significant differences were observed among the groups for the fracture load (p < 0.0001). MM frameworks showed the highest fracture load values. The PEEK group registered higher fracture load values than zirconia samples. The Weibull statistics corroborated these results. The fracture pattern was different among the groups. Conclusions: Milled metal provided the highest fracture load values, followed by PEEK, and zirconia. However, all tested groups demonstrated clinically acceptable fracture load values higher than 1000 N. PEEK might be considered a promising alternative for posterior FPDs.

scholarly journals Comparison of Fracture Resistance in Thermal and Self-Curing Acrylic Resins—An In Vitro Study

Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1234
Author(s):  
António Sérgio Silva ◽  
Aurora Carvalho ◽  
Pedro Barreiros ◽  
Juliana de Sá ◽  
Carlos Aroso ◽  
...  
Keyword(s):  
Fracture Resistance ◽  
Research Work ◽  
Testing Machine ◽  
In Vitro Study ◽  
Dimensional Accuracy ◽  
Acrylic Resin ◽  
Thermosetting Resins ◽  
Acrylic Resins ◽  
The Difference

Thermal and self-curing acrylic resins are frequently and versatilely used in dental medicine since they are biocompatible, have no flavor or odor, have satisfactory thermal qualities and polishing capacity, and are easy and fast. Thus, given their widespread use, their fracture resistance behavior is especially important. In this research work, we comparatively analyzed the fracture resistance capacity of thermo and self-curing acrylic resins in vitro. Materials and Methods: Five prosthesis bases were created for each of the following acrylic resins: Lucitone®, ProBase®, and Megacryl®, which were submitted to different forces through the use of the CS® Dental Testing Machine, usually mobilized in the context of fatigue tests. To this end, a point was defined in the center of the anterior edge of the aforementioned acrylic resin bases, for which the peak tended until a fracture occurred. Thermosetting resins were, on average, more resistant to fracture than self-curable resins, although the difference was not statistically significant. The thermosetting resins of the Lucitone® and Probase® brands demonstrated behavior that was more resistant to fracture than the self-curing homologues, although the difference was not statistically significant. Thermosetting resins tended to be, on average, more resistant to fracture and exhibited the maximum values for impact strength, compressive strength, tensile strength, hardness, and dimensional accuracy than self-curing resins, regardless of brand.

scholarly journals Experimental tests of PVD AlCrN-coated planer knives on planing Scots pine (Pinus sylvestris L.) under industrial conditions

2021 ◽  
Author(s):  
Krzysztof Nadolny ◽  
Wojciech Kapłonek ◽  
Marzena Sutowska ◽  
Paweł Sutowski ◽  
Piotr Myśliński ◽  
...  
Keyword(s):  
Research Work ◽  
Experimental Tests ◽  
Technical Condition ◽  
Cutting Edge ◽  
Raw Material ◽  
Edge Condition ◽  
Wear Area ◽  
Pine Wood ◽  
Wood Processing ◽  
Machining Operations

AbstractRaw pine wood processing and especially its mechanical processing constitute a significant share among technological operations leading to obtaining a finished product. Stable implementation of machining operations, ensuring long-term repeatable processing results depends on many factors, such as quality and invariability of raw material, technical condition of technological equipment, adopted parameters of work, qualifications and experience of operators, as well as preparation and properties of the machining tools used. It seems that the greatest potential in the search for opportunities to increase the efficiency of machining operations has the modification of machining tools used in it. This paper presents the results of research work aimed at determining how the life of cutting tools used in planing operations of wet pine wood is affected by the application of chromium aluminum nitride (AlCrN) coating to planar industrial planing knives in the process of physical vapour deposition. For this purpose operational tests were carried out under production conditions in a medium-sized wood processing company. The study compares the effective working time, rounding radius, the profile along the knife (size of worn edge displacement, wear area of the cutting edge), selected texture parameters of the planar industrial planing knife rake face and visual analyses of cutting edge condition of AlCrN-coated planar knives and unmodified ones. The obtained experimental results showed the possibility of increasing the life of AlCrN-coated knives up to 154% compared to the results obtained with uncoated ones. The proposed modification of the operational features of the knives does not involve any changes in the technological process of planing, does not require any interference with the machining station nor its parameters, therefore enabling rapid and easy implementation into industrial practice.

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