scholarly journals Characterization of properties and deterioration by termites in the Pinus elliottii Engelm. wood

2020 ◽  
Vol 19 (3) ◽  
pp. 252-257
Author(s):  
Ezequiel Gallio ◽  
Henrique Weber Dalla Costa ◽  
Laíse Guerreiro ◽  
Nidria Dias Cruz ◽  
Rafael Beltrame ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Basic Density ◽  
Physical And Mechanical Properties ◽  
Hardness Test ◽  
Pinus Elliottii ◽  
Linear Shrinkage ◽  
Chemical Components ◽  
Technological Properties ◽  
Anisotropy Coefficient ◽  
Technological Parameters

The technological properties of wood are constituted by parameters, which after being analyzed, make it possible to define an appropriate use for this material. However, the deterioration of the wood due to the attack of termites, which find their food source in the chemical components, ends up altering these original technological characteristics, reducing their useful life and compromising their use. Thus, this study aimed to determine some technological properties of Pinus elliottii, as well as to evaluate the influence of deterioration caused by Nasutitermes termites in this wood. Specimens with dimensions of 20 x 20 x 150 mm (tangential x radial x longitudinal) were used as specimens. The physical properties evaluated were the basic density and linear shrinkage (tangential and radial contractions, and anisotropy coefficient), while the mechanical properties were represented through the Janka hardness test and compression parallel to the fibers. After 40 days of the biodeterioration test with Nasutitermes termites, changes in the equilibrium moisture content, retractability, water absorption rate and mechanical properties were evaluated. While the physical and mechanical properties evaluated showed values similar to those found in the literature, the deterioration caused by termites caused a reduction in hardness and parameters related to compression, increasing the dimensional instability of the wood, represented by the variation in the anisotropy coefficient. This made it possible to conclude that the biodeterioration resulting from the attack of termites directly affected the technological parameters of the wood, and consequently, its quality for the use in the purpose it could initially be destined.

scholarly journals Decay Process Characteristics and Fungal Community Composition of Salix psammophila Sand Barriers in an Arid Area, Northern China

2021 ◽  
Vol 13 (14) ◽  
pp. 7590
Author(s):  
Xia Yang ◽  
Yumei Liang ◽  
Yong Gao ◽  
Ruidong Wang
Keyword(s):  
Mechanical Properties ◽  
Fungal Community ◽  
Basic Density ◽  
Physical And Mechanical Properties ◽  
Decay Process ◽  
Fungal Communities ◽  
Modulus Of Rupture ◽  
Chemical Components ◽  
Physical Parameters ◽  
Mechanical Index

With the increase in setting years in deserts, Salix psammophila sand barriers with different degrees of lodging damage caused by decay are losing wind-prevention and sand-fixation properties. In this study, we focus on the change in chemical properties of soils, and physical and mechanical properties of plants along different setting years; meanwhile, the change in fungal communities has been analyzed using high-throughput sequencing technology. The results show that a change in physical and mechanical properties and the loss of primary chemical components led to the degradation of the protective properties of the barrier to different degrees. After five years of setting, the physical parameters of basic density and shrinkage rate decreased by 44.04% and 28.68%, respectively, and the loss of the modulus of rupture mechanical index declined by 62.72%. After seven years of setting, the mechanical indexes of the modulus of rupture decreased by 76.95%. Five and seven years represented important inflection points in the decay process. Sordariomycetes (53.75%) and Eurotiomycetes (19.78%) were the main fungal groups present during the decay of the sand barrier. The basic density, moisture content, cellulose, and lignin of the sand barrier were the main driving factors affecting the distribution of fungal communities. The mechanism on fungal community to the decay of sand barriers still needs further studies to keep the function of sand barriers in fragile desert ecosystems.

scholarly journals Effects of Lizardite Addition on Technological Properties of Forsterite-Monticellite Rich White Ceramics Prepared From Natural Magnesite and Dolomite

2020 ◽  
Author(s):  
Ahmed Manni ◽  
Achraf Harrati ◽  
Abdelilah El Haddar ◽  
Abdelwahed Chari ◽  
Ali Sdiri ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Ceramic Industry ◽  
Raw Materials ◽  
Physical And Mechanical Properties ◽  
Linear Shrinkage ◽  
Thermomechanical Properties ◽  
Raw Material ◽  
Technological Properties ◽  
X Ray Diffraction ◽  
Potential Use

Abstract Lizardite rich peridotite has never been used to prepare ceramic specimens, especially in Morocco. For this raison, potential use of naturally abundant lazirditic material from the Rif domain (NW morocco), as a supply for ceramic industry, has been evaluated. The effects of lizardite addition to magnesite and dolomite mixtures on the thermomechanical properties of the calcined ceramics were also detailed. To achieve this target, natural lizardite, magnesite and dolomite samples were collected in ultrabasic Beni Bousra massif. Those raw samples were used for the synthesis of a forsterite-monticellite rich ceramics. Both raw and sintered samples were characterized by x-ray diffraction (XRD), scanning electron microscope (SEM) and fourier transform infrared (FTIR). Main physical and mechanical properties were assessed and correlated to their respective microstructural changes. The obtained results showed that both magnesite and dolomite were mainly composed of MgCO3 and CaCO3. In contrast, lizardite sample showed high amounts of silica, magnesia and iron oxide. Technological tests indicated that the prepared mixtures had increased flexural strengths. An increased amount of lizardite in the initial mixtures enhanced mechanical properties of the prepared ceramic specimens. The same data showed that lizardite has led to a decrease in linear shrinkage during calcination and subsequently, the production of ceramics with the required technological properties. Thus, the preparation of lizardite-based ceramics from the raw material deposits of the Rif area, Morocco, is technically feasible, economically justifiable and socially desirable due to the contribution to the economic growth of the raw materials sector, especially ceramic industry.

scholarly journals RESEARCH OF PHYSICAL AND MECHANICAL PROPERTIES OF WOOD-FIBER MATERIALS

2020 ◽  
pp. 451-457
Author(s):  
Aleksandr Yur'yevich Vititnev ◽  
Yuriy Davydovich Alashkevich ◽  
Natal'ya Geral'dovna Chistova ◽  
Roman Aleksandrovich Marchenko ◽  
Venera Nurullovna Matygullina
Keyword(s):  
Mechanical Properties ◽  
Wood Fiber ◽  
Experimental Studies ◽  
Physical And Mechanical Properties ◽  
Production Method ◽  
Strength Properties ◽  
Grinding Process ◽  
Technological Parameters ◽  
Fiber Materials ◽  
Traditional Construction

This paper presents the results of experimental studies of the physical and mechanical properties of wood-fiber boards of the wet production method when regulating the design and technological parameters of the grinding process. This allowed us to determine the influence of the working clearance between the grinding discs and the concentration of fibre mass with the subject to of quality change wood fiber after defibrator using the developed construction of the disc fibrillation action on the physico-mechanical properties of boards. As a result of the experiment, regression models were obtained that adequately describe the studied grinding process and allow predicting the values of physical and mechanical properties of the finished product depending on the established  parameters process. A comparative analysis of the size and quality characteristics of the fiber semi-finished product and its fractional composition when using a developed construction the disc of refiner fibrillation action and a traditional design used in industry is carried out. The preferential efficiency of the grinding process under the fibrillating effect the disc of refiner in comparison with the traditional construction disc of refiner is established. As a result, there is a significant improvement in the quality indicators of the fiber semi-finished product and its composition due to the formation and predominance in the total mass of long and thin, respectively, flexible fibrillated fibers with high tile-forming properties, which allows to increase the strength properties of the product (by 20–25%), without using binding resins.

scholarly journals METHOD OF SAMPLE MANUFACTURING FROM MULTILAYER COMPOSITE MATERIALS FOR STUDYING THEIR MECHANICAL PROPERTIES

2018 ◽  
pp. 16-23
Author(s):  
Alsaid Mazen ◽  
Ali Salamekh
Keyword(s):  
Mechanical Properties ◽  
Composite Materials ◽  
Polymer Composite ◽  
Testing Machine ◽  
Physical And Mechanical Properties ◽  
Polymer Composite Materials ◽  
Technological Parameters ◽  
Cutting Out ◽  
Method Of Production ◽  
Economic Considerations

In the last decades there is increasing the need to apply polymer composite materials in different industries, particularly in shipbuilding. There are developing single structures made from polymer composite materials to be used on board ships. The article focuses on technology of manufacturing slabs from polymer composite materials to carry out mechanical testing in the laboratory special standard units. Mechanical properties of polymer composite materials depend on molding technologies. There has been described a technology of sample manufacturing from polymer composite materials reinforced with glass fiber mat with fiberglass plastics. The technique of testing the specified samples for tensile strength has been considered. The sizes and shapes of the samples as well as the technological parameters of the manufacturing process have been validated, depending on the standard requirements and the technological features of the testing machine. The physical and mechanical properties of the components that make up the composite materials are considered. The sequence of stacking layers for preparation of plates from composite materials is indicated. The dimensions of the plates for cutting out finished samples are determined, depending on the method of production. The way of laying plates from composite materials has been chosen on the base of economic considerations and conditions of accessibility. The obtained results of mechanical properties can be used in solving problems of application of polymer composite materials in shipbuilding, for example, in manufacturing superstructures of some dry cargo vessels.

Laser Surface Cladding of Al-Si Alloy

2005 ◽  
Vol 297-300 ◽  
pp. 2813-2818 ◽  
Author(s):  
Xun Cai ◽  
Xiaoyu Yang ◽  
Tao Zhao ◽  
Liuhe Li ◽  
Qiu Long Chen
Keyword(s):  
Mechanical Properties ◽  
Wear Resistance ◽  
Laser Scanning ◽  
Sudden Change ◽  
Physical And Mechanical Properties ◽  
Laser Surface ◽  
Chemical Components ◽  
Interface Zone ◽  
Gradient Layer ◽  
Modified Layer

The mixture of Ni based alloy powder and WC particles were used as a feeding material to modify the surface properties of cast Al-Si alloy using a CO2 continuous transverse flow laser beam with maximum power of 10 kW. Microstructures and chemical components of the laser surface cladding (LSC) layers were studied using SEM, XRD, TEM and EDS. It is shown that the LSC layers were composed of γ-（ Ni, Cr, Fe, W）matrix phase and many enhancing phases, such as Ni2Al3, Ni3Al, WC, W2C, Cr2B, etc.. The microstructure of the LSC layers was greatly affected by the scanning rate b V and the powder of feeding rate p m under the same laser power. With the increasing of b V and p m , the dissolution phenomenon of WC particles was improved; the length, the diameter and the amount of the acicular constituent were markedly reduced. Microhardness and wear resistance tests were also performed: the average microhardness of the LSC layers was around 5.1 to 5.9GPa, which was five times higher than that of the Al-Si substrate. The wear resistance of the layer was about 20 times as big as that of cast Al-Si alloy when P=6kW, b V =13.3mm s-1, p m =100mg s-1, L=500N. The results showed that the mechanical properties of LSC layers on cast Al-Si alloy can be markedly enhanced with proper processing parameters. However, due to the sudden change of physical and mechanical properties between laser modified layer and substrate, some defects, especially crack, actually occur in the surface modified layer and the interface zone. And finally Ni/WC surface gradient layer was obtained on cast Al-Si alloy through thrice laser scanning technique. The microhardness of the laser gradient layer gradually changed from surface to substrate, so that it can reduce stress concentration in the whole laser surface layer, especially in the interface zone.

Production of mullite‒TiC‒с-BN‒с-ZrO2-materials by the method of plasma-spark sintering and their properties

2019 ◽  
pp. 23-29 ◽  
Author(s):  
A. V. Hmelov
Keyword(s):  
Mechanical Properties ◽  
Phase Composition ◽  
Elastic Modulus ◽  
Linear Correlation ◽  
Modulus Of Elasticity ◽  
Physical And Mechanical Properties ◽  
Linear Shrinkage ◽  
Physicomechanical Properties ◽  
Intensive Development ◽  
Crystalline Microstructure

The effect of different с-BN and с-ZrO2 ratios on the phase composition, microstructure, relative density, open porosity, linear shrinkage, physicomechanical properties, and linear correlation of the elastic modulus and toughness of samples during plasma-spark sintering at pressing load 70 MPa in the range of 1200‒1600 °C is shown. The synthesized powders of TiC, c-BN and c-ZrO2, sintered at 1400 °C by the plasma-spark method, are characterized by intense crystallization of the phases. Sintered samples with different ratios of c-BN and c-ZrO2 show the intensive development of mullite and TiC. An increase in the c-BN / c-ZrO2 ratio promotes an active increase in c-BN and a less intensive increase in с-ZrO2 in the range of 1200‒1600 °C, and it causes the formation of a less uniform and densely sintered crystalline microstructure with a large number of pores at 1500 °C. This sample has lower values of physical and mechanical properties and a lower linear correlation of the modulus of elasticity and toughness in the range of 1200‒1600 °C and lower crack resistance at 1500 °C. Ill. 9. Ref. 13. Tab. 1.

Use of Ash from the Incineration of Elephant Grass (Pennisetum purpureums shaum) into Clayey Ceramic

2012 ◽  
Vol 727-728 ◽  
pp. 993-998 ◽  
Author(s):  
A.M.F.D. Silva ◽  
L.S. Lovise ◽  
Sérgio Neves Monteiro ◽  
Carlos Maurício Fontes Vieira
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Large Scale ◽  
Chemical Characterization ◽  
Physical And Mechanical Properties ◽  
Linear Shrinkage ◽  
The Other ◽  
Industrial Processes ◽  
Elephant Grass ◽  
Calcium Compounds

Ashes generated in industrial processes are usually discarded and contribute to environmental pollution. Large scale incorporation into clayey ceramic products for civil construction, such as bricks and tiles, could be a permanent solution. Based on this rationale, this works has as its objective to characterize an ash waste from the incineration of elephant grass and to evaluate its incorporation into a clay to produce red ceramic. The waste was submitted to mineralogical and chemical characterization. Compositions were prepared with incorporation of the waste in amounts of up to 20 wt.% into the clay. Specimens were prepared by extrusion and fired in a laboratory furnace at 850°C. The physical and mechanical properties evaluated were: linear shrinkage, water absorption and flexural strength. The results showed that the waste is mainly composed of quartz and calcium compounds that sensibly reduce the linear shrinkage and does not change the other properties of the ceramic.

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