scholarly journals A STUDY ON MECHANICAL PROPERTIES AND STRUCTURE OF ANHYDRITE BINDER MODIFIED BY ULTRA-DISPERSED SILTSTONE

2020 ◽  
Vol 11 (3) ◽  
pp. 78-86
Author(s):  
Yury Tokarev ◽  
Grigory Yakovlev ◽  
Zarina Saidova ◽  
Valery Grakhov ◽  
Alexander Buryanov ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Microstructural Analysis ◽  
Physical And Mechanical Properties ◽  
Uniform Structure ◽  
Calcium Sulfate Dihydrate ◽  
Mineral Additive ◽  
Lower Porosity ◽  
Combined Action ◽  
First Time ◽  
Crystalline Hydrates

This research is devoted to modification of physical and mechanical properties and structure of a binder based on natural anhydrite. A sedimentary rock siltstone was added into the composition as a mineral ultrafine additive. The presence of aluminosilicate minerals proves that finely ground siltstone can be used as a mineral additive in the composition of the anhydrite binder, accelerating crystallization of gypsum new formations and densifying the structure of gypsum stone. For the first time, the effectiveness of using sodium and ammonium phosphates as hardening activators of an anhydrite binder was shown. Siltstone, added to the composition in the amount from 0 to 5%, lead to up to 40% increase in strength, which is due to the action of siltstone particles as “crystallization centers” and formation of crystalline hydrates of calcium sulfate dihydrate on their surface. Combined action of calcined siltstone and lime leads to a 45% increase in strength due to the additional compaction by new hydration products formed in the course of metakaolin and lime interaction. Microstructural analysis showed that samples with calcined siltstone and lime have a more dense and uniform structure with a lower porosity, compared to those with only natural siltstone.

scholarly journals Enhancement of Mechanical Properties and Porosity of Concrete Using Steel Slag Coarse Aggregate

Materials ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 2865
Author(s):  
Md Jihad Miah ◽  
Md. Munir Hossain Patoary ◽  
Suvash Chandra Paul ◽  
Adewumi John Babafemi ◽  
Biranchi Panda
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Microstructural Analysis ◽  
Steel Slag ◽  
Physical And Mechanical Properties ◽  
Length Change ◽  
Sustainable Building ◽  
Burnt Clay ◽  
Lower Porosity ◽  
Furnace Steel

This paper investigates the possibility of utilizing steel slags produced in the steelmaking industry as an alternative to burnt clay brick aggregate (BA) in concrete. Within this context, physical, mechanical (i.e., compressive and splitting tensile strength), length change, and durability (porosity) tests were conducted on concrete made with nine different percentage replacements (0%, 10%, 20%, 30%, 40%, 50%, 60%, 80%, and 100% by volume of BA) of BA by induction of furnace steel slag aggregate (SSA). In addition, the chemical composition of aggregate through X-ray fluorescence (XRF) analysis and microstructural analysis through scanning electron microscopy (SEM) of aggregates and concrete were performed. The experimental results show that the physical and mechanical properties of concrete made with SSA were significantly higher than that of concrete made with BA. The compressive and tensile strength increased by 73% when SSA fully replaced BA. The expansion of concrete made with SSA was a bit higher than the concrete made with BA. Furthermore, a significant lower porosity was observed for concrete made with SSA than BA, which decreased by 40% for 100% SSA concrete than 100% BA concrete. The relation between compressive and tensile strength with the porosity of concrete mixes are in agreement with the relationships presented in the literature. This study demonstrates that SSA can be used as a full replacement of BA, which is economical, conserves the natural aggregate, and is sustainable building material since burning brick produces a lot of CO2.

scholarly journals Effect of Hot Isostatic Pressing on Porosity and Mechanical Properties of 316 L Stainless Steel Prepared by the Selective Laser Melting Method

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4377
Author(s):  
Tomas Cegan ◽  
Marek Pagac ◽  
Jan Jurica ◽  
Katerina Skotnicova ◽  
Jiri Hajnys ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Hot Isostatic Pressing ◽  
Microstructural Analysis ◽  
Scanning Speed ◽  
High Yield ◽  
Laser Method ◽  
Preparation Conditions ◽  
Lower Porosity ◽  
316 L Stainless Steel

The manufacturing route primarily determines the properties of materials prepared by additive manufacturing methods. In this work, the microstructural features and mechanical properties of 316 L stainless steel prepared by the selective laser method have been determined. Three types of samples, (i) selective laser melted (SLM), (ii) selective laser melted and hot isostatic pressed (HIP) and (iii) selective laser melted and heat treated (HT), were characterized. Microstructural analysis revealed that SLM samples were formed by melt pool boundaries with fine cellular–dendritic-type microstructure. This type of microstructure disappeared after HT or HIP and material were formed by larger grains and sharply defined grain boundaries. The SLM-prepared samples contained different levels of porosity depending on the preparation conditions. The open interconnected LOF (lack of fusion) pores were observed in the samples, which were prepared with using of scanning speed 1200 mm/s. The blowhole and keyhole type of porosity were observed in the samples prepared by lower scanning speeds. The HIP caused a significant decrease in internal closed porosity to 0.1%, and a higher pressure of 190 MPa was more effective than the usually used pressure of 140 MPa, but for samples with open porosity, HIP was not effective. The relatively high yield strength of 570 MPa, tensile strength of 650 MPa and low ductility of 30–34% were determined for SLM samples with the lower porosity content than 1.3%. The samples after HIP showed lower yield strengths than after SLM (from 290 to 325 MPa) and relatively high ductility of 47.8–48.5%, regardless of the used SLM conditions.

Lightweight Concrete Based on Gypseous Binding Materials, Modified with Microcrystalline Cellulose, and Cavitationly Processed Sawdust

2019 ◽  
Vol 945 ◽  
pp. 188-192 ◽  
Author(s):  
A.A. Pykin ◽  
E.Y. Gornostaeva ◽  
N.P. Lukutsova ◽  
J.S. Pykina
Keyword(s):  
Mechanical Properties ◽  
Microcrystalline Cellulose ◽  
Lightweight Concrete ◽  
Physical And Mechanical Properties ◽  
High Strength ◽  
Water Soluble ◽  
Waste Wood ◽  
Matrix Microstructure ◽  
Calcium Sulfate Dihydrate ◽  
Reducing Substances

The physical and mechanical properties of lightweight constructional heat-insulating concrete (sawdust gypsum concrete) with high-strength gypsum binder, modified by food cotton microcrystalline cellulose and organic fillers of plant origin from the waste wood of coniferous and deciduous species in the form of cavitationly processed pine and birch sawdust have been studied. The dependence of the cavitation extraction time of water-soluble reducing substances (sugars) from sawdust on the strength of sawdust gypsum concrete is established. The changes in microstructure of the gypsum matrix, the mean density, bending tension strength and compression strength, the thermal conductivity coefficient of sawdust gypsum concrete on the basis of the cavitationly processed sawdust with the introduction of microcrystalline cellulose are analyzed. It is proven that microcrystalline cellulose compacts the space between the crystalline hydrates of calcium sulfate dihydrate in the gypsum matrix microstructure and improves the physical and mechanical properties of sawdust gypsum concrete.

scholarly journals Extracellular Matrix Hydrogels Originated from Different Organs Mediate Tissue-Specific Properties and Function

2021 ◽  
Vol 22 (21) ◽  
pp. 11624
Author(s):  
Tzila Davidov ◽  
Yael Efraim ◽  
Rotem Hayam ◽  
Jacopo Oieni ◽  
Limor Baruch ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Extracellular Matrix ◽  
Pluripotent Stem Cells ◽  
Physical And Mechanical Properties ◽  
Tissue Specific ◽  
Gene Expression Analyses ◽  
Composition Structure ◽  
Induced Pluripotent ◽  
And Function ◽  
First Time

Porcine extracellular matrix (pECM)-derived hydrogels were introduced, in recent years, aiming to benefit the pECM’s microstructure and bioactivity, while controlling the biomaterial’s physical and mechanical properties. The use of pECM from different tissues, however, offers tissue-specific features that can better serve different applications. In this study, pECM hydrogels derived from cardiac, artery, pancreas, and adipose tissues were compared in terms of composition, structure, and mechanical properties. While major similarities were demonstrated between all the pECM hydrogels, their distinctive attributes were also identified, and their substantial effects on cell-ECM interactions were revealed. Furthermore, through comprehensive protein and gene expression analyses, we show, for the first time, that each pECM hydrogel supports the spontaneous differentiation of induced pluripotent stem cells towards the resident cells of its origin tissue. These findings imply that the origin of ECM should be carefully considered when designing a biomedical platform, to achieve a maximal bioactive impact.

The Effect of Andreasen ́s Packing Distribution Modulus on the Physical and Mechanical Properties of a Low Cement Refractory Castable

2019 ◽  
Vol 1156 ◽  
pp. 97-104
Author(s):  
Vitoria Gabrieli Malimpensa ◽  
José Antonio Alves Júnior ◽  
João Baptista Baldo
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Refractory Concrete ◽  
Physical And Mechanical Properties ◽  
Dynamic Elastic Modulus ◽  
Conventional Concrete ◽  
Key Indicator ◽  
Temperature Ranges ◽  
S Model ◽  
First Time

Among modern refractory concretes (MRC), those with low cement content (LCC) where CAC = 4-6wt%, are widely commercialized, considering that their properties approximate those of burned bricks of the same class. In this work, the effect of the modulus q of Andreasen ́s particle size distribution, on the physical (porosity, bulk density) and mechanical (flexural strength and dynamic elastic modulus) properties, of either pre-fired or simply dried specimens of a ≥85% Al2O3 LCC ́s, was investigated. The different LCC ́s samples were formulated according to the Andreasen ́s model, using several distribution modulus (q = 0.22, 0.26, 0.30, 0.33 and 0.42). Measurements of the Dynamic Elastic Modulus (DEM) as a function of temperature (25 to 1500°C), using the Impulse Excitation Technique (IET), were taken as a key indicator of the microstructure dynamic behavior. For the sake of just a punctual comparative term, the physical and mechanical properties of a conventional type refractory concrete (CRC) with a higher CAC percentage (15%) formulated with q = 0.26 was also evaluated. The results indicated that distribution modulus values of; q =0.22, 0,26, 0.30 and 0.33 lead to higher DEM values. While q=0.42 lead to the smallest value in the LCC series. Also, higher DEM values ​​were obtained for LCC ́s (CAC = 5%) than for conventional concrete with CAC = 15% under the same value of q for pre-fired samples. In addition, by observing the occurrence of damping effects in specific temperature ranges, the loss of crystallization water from the calcium aluminate hydrates, as well as the development of pyroplastic behavior could be inferred. The gathered information is relevant to predict the behavior of LCC ́s and CRC ́s when put into service for the first time.

The improvement of physical and mechanical properties of sealers based on nitrile-butadiene rubber and combination of nano-metal oxides

2020 ◽  
pp. 174-182
Author(s):  
R.F. Khankishiyeva ◽  
◽  
H.N. Akhundzada ◽  
Keyword(s):  
Mechanical Properties ◽  
Metal Oxides ◽  
Chemical Interaction ◽  
Physical And Mechanical Properties ◽  
Mechanical Tests ◽  
Butadiene Rubber ◽  
Nanosized Powders ◽  
Nitrile Butadiene Rubber ◽  
Crosslinking Process ◽  
First Time

The chemical interaction of disulphochloride aromatic compounds with nitrile butadiene rubber (NBR) in the presence of combined nanosized powders of metal oxides (ZnO and Al2O3) was studied for the first time. Vulcanization of the prepared blends has been induced with two methods: by irradiation of gamma rays (D=300 kGy) and by pre-heating in the hydraulicpress and then subsequent irradiation (150 oC x 5', 300 kGy). In order to activate the crosslinking process, a combination of nano-oxides ZnO and Al2O3 were used. The surface of the nanocomposite was studied by using scanning electron microscopy. The mechanical properties of modified blends were studied and then compared with controlling sample (vulcanized with sulphur) and analyzed by the mechanical tests in aggressive environments after thermal aging. The study found that the use of 1,3-disulphochloride benzene with nano oxides produces cured materials with good resistance to aging and provides high service properties in air, seawater, and oil-bearing solution.

scholarly journals Nanostructured Films Produced from the Bleached Pinus sp. Kraft Pulp

2019 ◽  
Vol 26 (4) ◽  
Author(s):  
Lívia Cássia Viana ◽  
Graciela Ines Bolzon de Muñiz ◽  
Washington Luiz Esteves Magalhães ◽  
Alan Sulato de Andrade ◽  
Silvana Nisgoski ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Kraft Pulp ◽  
Physical And Mechanical Properties ◽  
Compact Structure ◽  
Nanostructured Films ◽  
Bleached Kraft Pulp ◽  
Lower Porosity ◽  
Density Values ◽  
Number Of Passes

ABSTRACT This study investigates the physical and mechanical properties of nanostructured films produced from Pinus sp. kraft pulp. To obtain the nanocellulose, the bleached kraft pulp was submitted to six different grinding regimes: two, five, ten, 20, 30, and 40 passes through the grinder. The influence of the number of passes was evaluated through the films’ physical and mechanical properties. The results show that the nanofibers reduced the thickness and considerably increased the density values of the fabricated films. The tensile strength increased more than 300% and the burst index was ten times higher in relation to normal papers. The more compact structure and lower porosity caused by the larger contact surface between nanofibers in the nanostructured films resulted in higher values of density, tensile strength, and burst resistance.

scholarly journals Printability and properties of 3D-printed poplar fiber/polylactic acid biocomposite

BioResources ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. 2774-2788
Author(s):  
Zhaozhe Yang ◽  
Xinhao Feng ◽  
Min Xu ◽  
Denis Rodrigue
Keyword(s):  
Mechanical Properties ◽  
3D Printing ◽  
Rheological Properties ◽  
Layer Thickness ◽  
Polylactic Acid ◽  
Physical And Mechanical Properties ◽  
Longitudinal Stripe ◽  
3D Printed ◽  
First Time ◽  
Printing Parameters

To efficiently and economically utilize a wood-plastic biocomposite, an eco-friendly biocomposite was prepared using modified poplar fiber and polylactic acid (PLA) via 3D printing technology for the first time. First, the effects of poplar fiber (0, 1, 3, 5, 7, and 9%) on the mechanical and rheological properties of the printed biocomposites were investigated. Subsequently, the printing parameters, including printing temperature, speed, and layer thickness, were optimized to obtain the biocomposite with superior properties. Finally, four printing orientations were applied to the biocomposite based on the optimized printing parameters to study the effect of filament orientation on the properties of the biocomposite. Favorable printability and mechanical properties of the biocomposite were obtained at 5% poplar fiber. The optimal printing temperature of 220 °C, speed of 40 mm/s, and layer thickness of 0.2 mm were obtained to produce the desired mechanical properties of the biocomposite with the printing orientation in a longitudinal stripe. However, the printing parameters should be chosen according to the applications, where different physical and mechanical properties are needed to achieve efficient and economical utilization of the biocomposites.

scholarly journals Improving the surface quality and mechanical properties of selective laser sintered PA2200 components by the vibratory surface finishing process

2021 ◽  
Vol 3 (3) ◽  
Author(s):  
Hamaid M. Khan ◽  
Tolga B. Sirin ◽  
Gurkan Tarakci ◽  
Mustafa E. Bulduk ◽  
Mert Coskun ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Surface Roughness ◽  
Tensile Strength ◽  
Additive Manufacturing ◽  
Microstructural Analysis ◽  
Surface Hardness ◽  
Physical And Mechanical Properties ◽  
Surface Finishing ◽  
Finishing Process ◽  
Wide Range

Abstract This paper attempts to improve the physical and mechanical properties of selective laser sintered polyamide PA2200 components through a vibratory surface finishing process by inducing severe plastic deformation at the outer surface layers. The industrial target of additive manufacturing components is to obtain structures having surface roughness, hardness, and other mechanical properties equivalent to or better than those produced conventionally. Compared to the as-built SLS PA2200 samples, vibratory surface finishing treated specimens exhibited a smooth surface microstructure and more favorable roughness, hardness, and tensile strength. Also, the duration of the vibratory surface finishing process showed a further improvement in the surface roughness and hardness of the SLS samples. Compared to the as-built state, the roughness and hardness of the surface-treated samples improved by almost 90% and 15%, respectively. Consequently, microstructural analysis indicates that lower surface roughness and enhanced surface hardness is a crucial factor in influencing the overall tensile strength of SLS-PA2200 components. We consider that the combination of VSF and SLS processes can successfully handle a wide range of potential applications. This study also highlights the efficiency and applicability of the vibratory surface finishing process to other additive manufacturing processes and materials. Graphic abstract

Structural Conformation of Polytetrafluoroethylene Composite Matrix

2016 ◽  
Vol 10 (2) ◽  
pp. 241-246 ◽  
Author(s):  
Oleg Budnik ◽  
◽  
Anatoliy Budnik ◽  
Valentin Sviderskiy ◽  
Kristina Berladir ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Activation ◽  
Supramolecular Structure ◽  
Physical And Mechanical Properties ◽  
Composite Matrix ◽  
Service Properties ◽  
Operating Modes ◽  
Structural Conformation ◽  
First Time

Enhancement of physical and mechanical properties and structuring activity of polytetrafluoroethylene as matrix of composites by means of mechanical activation is shown. Operating modes of mechanical activation equipment are defined, in which the service properties of PTFE are maximized. The effect of mechanical activation technology on restructuring and change of morphology and supramolecular structure of PTFE is detected for the first time.

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