Maximum Values Of Bending Strength Research Articles

Study of the Composition and Properties of Bivalve Mollusk Shells as Promising Bio-Indifferent Materials for Photocatalytic Applications (Example of Practical Use)

This paper studies the composition and properties of shells of bivalve mollusks (Crenomytilus grayanus, Callista brevisiphonata, and Mizuhopecten yessoensis) from coastal discharges with a view to the possibility of their use in photocatalytic water treatment systems. The clam shells are considered in terms of application in the form of a powder material as a precursor for creating photocatalysts, and also as a carrier of photocatalytic coatings. It was shown that the main phase composing the shell material was calcium carbonate in two crystallographic modifications—calcite and aragonite. The presence of inorganic impurities in all studied clam shells did not exceed one mass percent. The main share was made up of elements included in the composition of calcium carbonate, which confirmed the high bio-indifference of the materials under study. Depending on the physiological and environmental features of the structure of clam shells, different contents of the organic component in their composition were observed. The granulometric characteristics of crushed clam shells (average diameter, specific surface area, and distribution modality) were studied. It was shown that the maximum values of bending strength of 5 MPa and compressive strength of 2 MPa are characterized by Mizuhopecten yessoensis shells with the lowest porosity of 2.91%. The features of sorption and photosorption processes of both whole and crushed shells in relation to four organic dyes at different temperatures and degrees of illumination were studied. Based on crushed shells of Mizuhopecten Yessoensis and titanium dioxide, functional materials (CaxTiyOz) were obtained, and their morphology and photocatalytic properties were studied. An example of the practical use of clam shells as a carrier of a photocatalytic coating is given.

ANALISIS BENDING PADA KOMPOSIT SERAT ALAM DAUN AGEL DENGAN RESIN EPOXY

The use of composite materials, especially those developed by natural fibers in various equipment, has begun to develop a lot, the use of natural agel leaf fibers as composite materials can reduce the use of synthetic materials and increase the utilization of agel leaf natural fibers which are still a lot of wasted. This study aims to determine the stages or processes of agel leaf natural fiber composite using 2 methods of hand lay up, vacuum bag and to determine the value of the bending strength of agel leaf natural fiber material between variations of the epoxy matrix in the direction of the fibers 0^° and 〖90〗^°.Based on the data from the test results, it can be concluded that the average value of maximum bending strength in agel leaf natural fiber composites using the vacuum bag manufacturing method with a volume fraction of 60% and fiber direction 0^° and 〖90〗^° has an average maximum bending strength value that is the highest, namely 11.006 MPa and 11.057 MPa and the composite of agel leaf natural fiber using the hand lay up method (non vacuum bag) with a volume fraction of 50%, 60%, 70% and fiber direction 0^° has the lowest average maximum bending strength values of 3.413 MPa, 5.404 MPa, 4.625 MPa.

Effect of Processing Parameters on the Structure and Properties of Powder Fe–Al Intermetallic Compounds Obtained by Sintering and Impulse Hot Pressing

The paper examines the effect of high-energy grinding and post-treatment conditions on the structure and physical and mechanical properties of iron aluminide Fe–15 wt.% Al obtained by sintering and impulse hot pressing. It was shown that the grinding of a mixture of iron and aluminum powders in a planetary mill results in the formation of lamellar particles whose morphology is preserved in the alloy structure after sintering and impulse hot pressing. After grinding, sintered intermetallic compounds obtained from powder mixtures demonstrate low physical and mechanical properties due to the low quality of grain boundaries. The use of impulse hot pressing for compaction of samples from milled powders at temperatures of 850–1150°C significantly increases the density of intermetallic compounds compared to sintered materials of a similar composition—from 5 to 6.5 g/cm3. The increase in the temperature of impulse hot pressing contributes to an increase in mechanical characteristics, where the maximum values of bending strength and fracture toughness are 880 MPa and 21 MPa · m0.5, respectively. Subsequent hightemperature annealing (1350–1450°C) leads to an improvement of the quality of grain boundaries with the formation of a predominantly discontinuous grid, coagulation of impurity segregation, and, as a result, to a sharp increase in bending strength and fracture toughness, which are 1400 MPa and 27 MPa · m0.5, respectively. It was shown that the interparticle rupture observed in the samples after impulse hot pressing at relatively low temperatures changes to transcrystalline after hightemperature annealing.

EFFECT OF INITIATOR CONCENTRATION ON THE MECHANICAL AND DEGRADATION PROPERTIES OF BAMBOO FABRIC REINFORCED POLYESTER RESIN COMPOSITES

This research work aims to fabricate bamboo fabric reinforced polyester composites (BFRPCs) and investigate the mechanical and degradation properties of BFRPCs. Composite samples were prepared using hand lay-up technique. Bamboo fabric was used as reinforcement material, unsaturated polyester resin (UPR) was used as matrix and Methyl ethyl ketone peroxide (MEKP) was used as initiator which was employed as 0.5, 1, 2, 3 and 4% concentration. The mechanical properties of the BFRPC samples such as tensile strength (TS), tensile modulus (TM), bending strength (BS), bending modulus (BM) and impact strength (IS) were conducted. The degradation behaviors of the composites in soil burial, immersed in alkaline water and saline water were also evaluated. The BFRPC sample with 2 (%) MEKP concentration showed better tensile properties with TS and TM values of 39 MPa and 744 MPa respectively. For the 1 (%) MEKP concentration, the maximum values of BS, BM and IS were found to be 62.8 MPa, 1229 MPa and 25.7 kJ/m2 respectively. In the case of soil burial degradation the BFRPC sample with 1 (%) MEKP concentration shows better performance against loss of TS. No significant effect was found on the alkaline and saline water degradation properties of BFPRC for the variation of MEKP concentration. With the increase of all types of degradation time, decrease the tensile strength of all BFRPC samples.

The effect of immersion with time and water variations on bending strength of malapoga wood (Toona Ciliata M. Roem)

Bending strength is a parameter used in wood structure planning. The purpose of this study was to determine the effect of time and water of immersion on increasing bending strength. The main ingredient of this research is malapoga wood (Toona Ciliata M. Roem) which was previously preserved by immersion with brackish water, sea water and river for 2,4,6 and 8 weeks. Bending strength specimen and testing procedure refer to ASTM D14. A cross section of the test specimen is then subjected to a macro photograph to determine its failure mechanism. The test results show that Immersion using river water gives a greater bending strength value followed by using brackish water and sea water. The maximum bending strength of the river water is 26. 64 MPa at the time of immersion 4 weeks later followed by brackish water at 25. 86 MPa while the maximum bending strength value of seawater occurs in immersion for 6 weeks which is 24. 52 MPa. The immersion time causes the malapoga wood to become denser due to all the cavities in the malapoga wood filled with material contained in brackish water, sea and river so that the fibers of malapoga wood close up, dry out and crystallize inside the malapoga wood cavity which causes the bending strength of malapoga to increase.

FABRICATION AND CHARACTERIZATION OF NANO-FE/WOODCERAMIC COMPOSITES

Furan resin added with γ -Fe 2 O 3 nanoparticles and Chinese fi r sawdust were mixed and compressed into boards. The boards were then sintered in a vacuum furnace to obtain a nano-Fe/ woodceramic composite. The phase constitution, microstructure, and element distribution of the composite were examined by using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy disperse spectroscopy (EDS), respectively. The mechanical properties, volume electrical resistivity, and wave adsorption properties were investigated. XRD analysis indicates that α-Fe, Fe3C, and graphite carbon exist in the nano-Fe/woodceramic composite, and α-Fe promotes the graphite degree of woodceramic. SEM and EDS observations indicate that the composite has a porous structure and α-Fe nanoparticles distributed in the woodceramic. Experimental results show that the maximum values of bending strength and compressive strength are 11.74 MPa and 13.86 MPa, respectively. The minimum value of volume electrical resistivity is 0.021 Ω$cm. The minimum reflection loss value is11.45 dB at 9.68 GHz with 3mm thickness of absorbing layer.

Elaborating the Cu-network structured of the W–Cu composites by sintering intermittently electroplated core-shell powders

The tungsten–copper composites are widely used in heat sink materials for high power circuits, electrical contact materials, and electrode materials because of their excellent thermal and mechanical properties. We elaborate the Cu-network structured of the W–Cu composites by sintering the intermittently electroplated core-shell powder. After hot-pressing sintering, the W particles dispersed uniformly within the continuous Cu phase. Thus, the bulk of the dense W–Cu composites demonstrated the desired Cu-network structure with high thermal conductivity. No distinct voids were found in the connection between W and Cu. Thermal conductivity increased with the increase of Cu content, and the maximum value was 274.23 W/(m·K). The high sintering density, the Cu-network structure, and the good interface of W and Cu are the main factors ensuring the excellent thermal performance of composites. The maximum values of bending strength (995 MPa) and hardness (240 HV) were achieved with the 20 wt % Cu sample. The deposition process of Cu coating during intermittent electroplating was also discussed.

Strengths of Basalt Fiber Reinforced Fir Sawdust Panel

Wood composite is weak under heavy loadings, which was improved by reinforcing basalt fibres. In this study, chopped basalt fibres with different lengths (5mm, 10mm, 15mm and 20mm) were mixed with fir sawdust at 2.5%, 5%, 7.5% and 10% weight fractions to produce basalt fiber reinforced fir sawdust panels. The reinforced panels showed improved strength values. A maximum bending strength value of 44.1 MPa was obtained when the mean length of chopped basalt fiber was 15mm and the weight fraction was 2.5%. The tensile strength reached a maximum value of 17.4MPa when the mean length of basalt fiber was 10mm and the weight fraction was 10%. Compared with the unreinforced fir sawdust panel group, the reinforced panel group increased bending strength 60.7% and had a 47.5% increase in tensile strength. These findings demonstrate that basalt fibre has very promising prospects for strength improving.

A Study on Mechanical Properties of PMMA/Hydroxyapatite Nanocomposite

This study is focused on the role of nano hydroxyapatite particles on the mechanical properties of PMMA/HA nanocomposites. In order to achieve a proper and homogeneous distribution of HA particles in the polymer matrix, mixer milling process was applied. Wear, compression and three-point bending tests were conducted. It was observed that wear rate decreased by increasing in HA content in both atmosphere and artificial saliva. The results of compression tests showed that the addition of 2.5 percent HA to PMMA promoted ultimate compressive strength, yield strength and modulus while caused to decrease elongation at break. Also it was elucidated that addition of HA more than 2.5 wt.% caused a decrease in both ultimate compressive strength and compression yield strength and an increase in elongation at break. The results of three-point bending tests on the PMMA cements containing 2.5 percent HA demonstrated the maximum bending strength value and modulus among all the HA containing formulations. However there was no direct proportionality between the results of bending tests and the HA content and the addition of HA to PMMA (up to 10 wt.%) did not change the bending properties significantly.

Strengthen of Porous Al<sub>2</sub>O<sub>3</sub> Ceramics by Adding Nanoparticle ZrO<sub>2</sub> Addition

In this paper, Nanoslurry-ZrO2 were added into alumina powders to improve the bending strength of macroporous Al2O3 Ceramic sintered at 1550°C, 1600°C, 1650°C corresponding for3h each in air, respectively. The results show that the bending strength of porous alumina ceramic was simultaneously greatly influenced by various ZrO2 contents. When ZrO2 content is 2wt%, the maximum bending strength value of sample heated at 1650°C was observed, which achieves to 50 MPa. And the maximum bending strength value of any sample also exists at 1650oC. By SEM analysis, many fine ZrO2 particles with high activity surface form a neck bonding which is beneficial to the improvements of bending strength.

Fabrication of Continuously Porous t-ZrO<sub>2</sub> Bodies Using Carbon Powder and Evaluate Their Biocompatibility

The continuously porous t-ZrO2 bodies were fabricated by the extrusion process. The average pore size of the 2nd passed samples was about 260μm in diameter. The maximum bending strength value was about 177MPa. For the evaluation of their biocompatibility, human osteoblast like MG-63 cells and osteoclast like Raw 264.7 cells were cultured on the top surface of the porous t-ZrO2 bodies. The osteoblast cells were grown with spindle shape, condensed circular growth and three-dimensional network type. In contrast, the osteoclast cells appeared with pebble stone structure.

Fabrication of HAp‐Coated Micro‐Channelled t‐ZrO2 Bodies by the Multi‐Pass Extrusion Process

HAp‐coated micro‐channelled t‐ZrO2 bodies were fabricated using a multi‐pass extrusion process in which carbon powders were used to facilitate the formation of pores and ethylene vinyl acetate was used as a binder. The unidirectional pores and HAp coating layers can be obtained easily, using the extrusion process. The micro‐channelled bodies were 180 μm in diameter, and the HAp layer was uniformly coated on the pore walls. However, after being sintered above 1200°C, the HAp decomposed and was transformed into β‐TCP, in which a large number of pores were observed. The maximum values of bending strength of HAp‐coated and uncoated porous t‐ZrO2 bodies sintered at 1500°C were about 116 and 173 MPa, respectively, and their relative densities were about 57% and 63%, respectively.

ピストン・シリンダー型高圧装置を用いた準安定単斜晶ジルコニア高密度セラミックスの作製

Single phase m-ZrO2 ceramics (∼13mmφ and 3-5mmt) have been fabricated using a piston-cylinder type high-pressure apparatus under 1GPa at 1023-1173K, in which a newly developed high-pressure cell has been utilized to introduce pseudo-isostatic pressure. Starting material, meta-stable m-ZrO2 powder prepared via a sol-gel method, was characterized by X-ray diffraction (XRD), differential thermal analysis (DTA), and transmission electron microscopy (TEM). Dense ceramics sintered at 1123K, free from macro-cracks, showed a high relative density of ∼ 99.5% and homogeneous microstructures consisting of fine grains (∼1μm). In-situ XRD analysis under high pressures and temperatures revealed that m- to t-ZrO2 transition took place around 1123K under 1GPa. Mechanical properties of m-ZrO2 ceramics have been evaluated ; the maximum values of bending strength (σb = 520MPa), Vickers hardness (Hv = 9.8GPa), and fracture toughness (KIC = 3.9MPa·m1/2) were achieved at the samples fabricated at 1123K.

Dependence of Mechanical Properties of MgO-C Bricks on Graphite Content

MgO-C bricks containing 0 to 30 vol% flake graphite and expanded graphite were prepared and heat-treated at 800 and 1400°C. The dependence of mechanical properties of the MgO-C bricks on the graphite content was studied. The maximum values of bending strength, elastic modulus and fracture toughness were obtained at 2 to 3 vol% expanded graphite and at around 5 vol% flake graphite. The effective fracture energy increased with an increase in graphite content up to 30 vol% for expanded graphite. However, no slight increase in effective fracture energy was observed above 20 vol% flake graphite. Thermal shock resistance parameters R″″ and Rst were calculated based on the data obtained. R″″ was not correlated with graphite content. On the other hand, Rst remarkably increased above 7 vol% graphite and larger Rst was obtained with expanded graphite. Consequently, improvement of the spalling resistance of MgO-C brick was expected with expanded graphite.