scholarly journals PHYSICAL-MECHANICAL CHARACTERIZATION OF THE WOOD OF Plathymenia reticulata BENTH (VINEYARD-OF-FIELD) NATIVE SPECIES OF THE CERRADO OF THE STATE OF TOCANTINS

FLORESTA ◽  
2020 ◽  
Vol 51 (1) ◽  
pp. 247
Author(s):  
Raquel Marchesan ◽  
Lucas Alves Ferreira Souza ◽  
Rodrigo Araújo Fortes ◽  
Raydel Lorenzo Reinaldo ◽  
André Orathes do Rego Barros ◽  
...  
Keyword(s):  
Native Species ◽  
Mechanical Characterization ◽  
Basic Density ◽  
Physical And Mechanical Properties ◽  
Mechanical Tests ◽  
The State ◽  
Native Forest ◽  
Average Value ◽  
Heavy Construction

Physical-Mechanical Characterization of the Wood of Plathymenia reticulata Benth (Vinhático-do-campo) Species of the Cerrado Biome of the State of Tocantins. The objective of this work was to determine the physical and mechanical properties of Plathymenia reticulata Benth (vinhático-do-campo) wood to indicate its potential use. The wood used in the production of the specimens came from the municipality of Dueré – TO native forest. The basic density, wood retractability, and anisotropy coefficient were obtained from physical tests, and the values of axial compression and static flexion resistance from the mechanical tests. The values obtained showed that the Plathymenia reticulata Benth wood fits the C40 resistance classification for hardwoods, determined by the Brazilian Standard (NBR7190). The average value of the basic density found was 0.64 g cm-3, classified as a medium density wood and the values of tangential, radial and volumetric retractability were 6.11%, 3.06%, 9.39 %, respectively. As for its mechanical characteristics, it presented average values of compressive strength parallel to the fibers, resistance to static flexion, and elastic modulus equal to 58.8MPa, 128.2 MPa, and 12760.0MPa, respectively. The vinhático-do-campo wood can be classified as stable wood and its physical characteristics suggest a normal quality. The species can be applied in light and heavy construction.

scholarly journals MECHANICAL STRENGTH OF COAL: METHODS OF DETERMINATION AND FACTORS OF INFLUENCE (REVIEW)

2021 ◽  
Vol 6 ◽  
pp. 4-17
Author(s):  
V.V Koval ◽  
D.V. Miroshnichenko ◽  
O.V. Bogoyavlenska
Keyword(s):  
Mechanical Strength ◽  
Physical Properties ◽  
Physical And Mechanical Properties ◽  
Mechanical Tests ◽  
Point Of View ◽  
Statistical Characteristics ◽  
Measuring Instruments ◽  
Industrial Processing ◽  
Average Value ◽  
Advantages And Disadvantages

The article substantiates the importance and problems of determining of such an indicator of the quality of solid fossil fuels, as mechanical strength. The strength of coal depends on a large number of factors (viscosity, brittleness, properties of structural bonds, etc.), the change of which is impossible to take into account. Therefore, the strength of coal in the sample, piece, pack and formation must be represented by some integral index, which inevitably fluctuates around a certain average value and can be determined only approximately. The evaluation of the strength properties of coal should be carried out on the basis of mass tests using statistical methods that allow to calculate the average value and coefficient of variation. Since the strength dispersion is mainly due to the natural inhomogeneity of the coal, the excessive accuracy of the measuring instruments has almost no effect on the statistical characteristics. Laboratory methods of mechanical tests of mine samples, in comparison with full-scale, as a rule, are very accessible and, at qualitative performance of tests, are highly reliable. The properties of coal as an object of enrichment and use are largely related to its physical properties. The physical properties of coal and mineral impurities significantly affect the formation of the main parameters that characterize the particle size distribution and fractional composition, it`s changes during the mining, transportation and enrichment processes. The basic physical and mechanical properties of solid fuels from the point of view of their industrial processing have been listed, the review has been made of the most widespread methods of study of coals mechanical durability and the equipment used for these purposes. The main advantages and disadvantages have been summarized of these methods, as well as their relationship. The factors have been Indicated tinfluencing the mechanical strength of coal. The expediency of using existing methods from the point of view of informativeness for thesphere of its application has been estimated. The methods common in the coal processing industry are considered in more detail. Keywords: coal, solid fuel mining, mechanical strength, determination methods, influencing factors, grinding strength, crushing index. Corresponding author V.V. Koval, e-mail: [email protected]

scholarly journals Mechanical Characterization of Nanocomposite Joints Based on Biomedical Grade Polyethylene under Cyclical Loads

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2681
Author(s):  
Annamaria Visco ◽  
Cristina Scolaro ◽  
Antonino Quattrocchi ◽  
Roberto Montanini
Keyword(s):  
Titanium Dioxide ◽  
Mechanical Response ◽  
Mechanical Characterization ◽  
Laser Light ◽  
Mechanical Tests ◽  
Fatigue Tests ◽  
Weight Content ◽  
Percentage Weight ◽  
Static Mechanical

Polymeric joints, made of biomedical polyethylene (UHMWPE) nanocomposite sheets, were welded with a diode laser. Since polyethylene does not absorb laser light, nanocomposites were prepared containing different percentages by weight of titanium dioxide as it is a laser absorbent. The joints were first analyzed with static mechanical tests to establish the best percentage weight content of filler that had the best mechanical response. Then, the nanocomposites containing 1 wt% titanium dioxide were selected (white color) to be subjected to fatigue tests. The experimental results were also compared with those obtained on UMMWPE with a different laser light absorbent nano filler (carbon, with greater laser absorbing power, gray in color), already studied by our research team. The results showed that the two types of joints had an appreciable resistance to fatigue, depending on the various loads imposed. Therefore, they can be chosen in different applications of UHMWPE, depending on the stresses imposed during their use.

scholarly journals Intraspecific variability of camu-camu fruit in native populations of northern Amazonia

2015 ◽  
Vol 15 (4) ◽  
pp. 265-271 ◽  
Author(s):  
Edvan Alves Chagas ◽  
Ricardo Manuel Bardales Lozano ◽  
Pollyana Cardoso Chagas ◽  
Christinny Giselly Bacelar-Lima ◽  
Maria Isabel Ribeiro Garcia ◽  
...  
Keyword(s):  
Hierarchical Clustering ◽  
Principal Components ◽  
Native Species ◽  
Intraspecific Variability ◽  
The State ◽  
Breeding Programs ◽  
Multivariate Technique ◽  
Myrciaria Dubia ◽  
Native Populations

Abstract Similarly to most breeding programs of native species, camu-camu (Myrciaria dubia (Kunt) McVaugh) improvement is also restricted, due to the scarcity of research results. In this situation, the prospection, collection and conservation of germplasm in genebanks ensure successful selection and breeding studies of the species. In this sense, the purpose of this study was the intraspecific characterization of the biometric variability in fruits of native camu-camu populations of the State of Roraima, in the northern Amazon region. Of 16 populations, 247 sub-samples were evaluated. Analyses were performed with the multivariate technique of principal components and hierarchical clustering, to determine the variables with highest intraspecific variability for the studied traits. The populations found in the lower Rio Branco region performed best for the studied traits, indicating the great potential of the region as a reservoir of promising subsamples for future breeding programs of the species in the northern Amazon.

scholarly journals Mechanical Characterization of Angustifolia Kunth and Rayada Amarilla Guadua Bamboo

2019 ◽  
Vol 303 ◽  
pp. 03002
Author(s):  
Brayan García ◽  
Camila Preciado ◽  
Mónica Bedoya ◽  
Oscar Mendoza
Keyword(s):  
Mechanical Properties ◽  
Mechanical Characterization ◽  
Construction Material ◽  
Construction Materials ◽  
Physical And Mechanical Properties ◽  
Fiber Direction ◽  
Three Point Bending ◽  
Compressive Stresses ◽  
Cylindrical Samples

Guadua is a Colombian endemic type of grass belonging to the bamboo family. It can be considered an alternative construction material due to its physical and mechanical properties, as well as a sustainable source of timber due to its fast growing process and high availability in tropical countries. The Guadua is composed by the stem petiole or lower part, the stem base, and the stem. In turn, the stem is divided into sections separated by diaphragms that form knots, called culms. The distance between knots and the structure of the longitudinal fibers in the culms depend on the age of the plant. This implies a difficulty when determining the mechanical properties of the stem, since there are not specific standards for this purpose. In this work the mechanical properties of young samples of Angustifolia Kunt and Rayada Amarilla Guadua, of around 6 years of growth, were characterized. To account for the natural variability introduced by the presence of diaphragms, cylindrical and prismatic samples were extracted without knot, with one knot in the middle, and with one knot at each end. Cylindrical samples were used to measure compressive strength parallel to the fiber direction, while prismatic samples were used to measure tensile strength also parallel to the fiber direction and flexural strength by three point bending. Methodologies from conventional construction materials were adapted for this purpose. The obtained results allowed concluding that the Guadua samples present different mechanical properties depending on the position of the knots. Samples with a knot in the middle are more resistant to compressive stresses, while the samples without knot are more resistant to flexural and traction stresses. The samples with one knot at each end presented a more balanced behavior, being efficient when exposed to compression, traction and flexural stresses.

Mechanical Characterization of Graphite and CNT Reinforced Aluminium-5083

2017 ◽  
Vol 889 ◽  
pp. 56-62 ◽  
Author(s):  
D.S. Robinson Smart ◽  
Nithin P. Johns ◽  
Joses Jenish Smart
Keyword(s):  
Corrosion Resistance ◽  
Base Metal ◽  
High Performance ◽  
Mechanical Characterization ◽  
Stir Casting ◽  
Mechanical Tests ◽  
Primary Objective ◽  
Aluminium Metal

Aluminium composites are widely used in a variety of applications including aerospace, automotive, defence, thermal as well as in sports and avocation. Technological and industrial demands often account to inculcating special properties to materials to achieve its target that may not be achieved by conventional materials. This phenomenon was widely observed in the recent decades in fields of aerospace and transport where high performance materials with low densities are required. The primary objective of this work is to develop an Aluminium Metal Matrix Composite (AMMC) by in-situ stir casting for naval applications and successfully bring about self-lubrication properties, thereby lowering wear rate and improving corrosion resistance. This is done by adding graphite at various weight fractions to the base metal. The fabricated composites are subjected to various mechanical tests and corrosion test. It was found that ,increase in graphite addition improves the Microhardness of the material, improves the wear resistance and enhances its corrosion resistance. The materials were further observed and found that , there will be lower tensile strengths compared to the base metal with increase in addition of graphite particles.

scholarly journals Agrigento Cathedral

2016 ◽  
pp. 975-1001
Author(s):  
Liborio Cavaleri ◽  
Maria Giovanna Saccone ◽  
Maurizio Costa ◽  
Calogero Foti ◽  
Giuseppe Basile
Keyword(s):  
Mechanical Characterization ◽  
The State ◽  
Fe Model ◽  
Structural Members ◽  
Safety Level ◽  
Foundation Soil ◽  
Experimental Campaign ◽  
Extensive Damage

At present Agrigento Cathedral is affected by extensive damage that seems to be mainly due to partial slumping of the foundation soil. The chapter deals with the state of damage that affects the cathedral and the investigation carried out for the mechanical characterization of the construction, the formulation of an FE model and the assessment of the safety level with respect to the service loads and with respect to exceptional loads like seismic ones. In the chapter the details of the above investigation are discussed, consideration also being given to the monitoring carried out in order to understand whether the phenomenon affecting the cathedral is ongoing. The results of the monitoring and the experimental campaign on the structural members are described, revealing an unexpectedly low capacity with respect to service loads. Then a comparison is carried out between the response of the FE model and the experimental observations for the identification of the causes of distress. Finally possible action is discussed.

Physical and Mechanical Properties of Alnus Formosana Wood Introduced into Sichuan

2014 ◽  
Vol 574 ◽  
pp. 411-415
Author(s):  
Ming Chen ◽  
Jian Hua Lyu
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Impact Toughness ◽  
Modulus Of Elasticity ◽  
Basic Density ◽  
Physical And Mechanical Properties ◽  
Modulus Of Rupture ◽  
Dry Density ◽  
Average Value ◽  
Mechanical And Physical Properties

The mechanical and physical properties of Alnus formosana wood from Sichuan, China were studied. Air-dry density, oven-dry density, basic density, shrinkage, swelling, parallel-to-grain compressive strength, parallel-to-grain tensile strength, modulus of rupture (MOR),modulus of elasticity (MOE) ,impact toughness were analyzed. Results from this study show that air-dry density, oven-dry density and basic density were respectively 0.52, 0.49 and 0.43g/cm3. The average value of volumetric shrinkage was 7.111% and the average value of volumetric swelling was 7.06%. The average values of modulus of elasticity (MOE) ,modulus of rupture (MOR), parallel-to-grain compressive strength, parallel-to-grain tensile strength and impact toughness were 8102.429 Mpa, 80.429 Mpa, 41.575Mpa, 81.542 Mpa and 47.406 Kj/m2 , respectively. This study solved a basic problem about the planting and utilization of Alnus formosana wood in Sichuan, China.

scholarly journals Mechanical characterization and reinforcement of the adobe material of the Chellah archaeological site

2020 ◽  
Vol 150 ◽  
pp. 03022
Author(s):  
Sana Simou ◽  
Khadija Baba ◽  
Nacer Akkouri ◽  
Mohammed Lamrani ◽  
Mohammed Tajayout ◽  
...  
Keyword(s):  
Building Materials ◽  
Mechanical Characterization ◽  
Archaeological Site ◽  
Mechanical Tests ◽  
Actual State ◽  
Historical Buildings ◽  
Support Intervention ◽  
Sem Study ◽  
Wood Shaving

The evaluation of historical buildings has always posed significant challenges due to the difficulties associated with the characterization of complex geometries, the variability of the properties of building materials and the actual state of damage to these structures. This challenge is even more complex when it concerns historical adobe masonry buildings, because earthen masonry has a high variability and rapid deterioration over time if it is not properly maintained. In the context of the previous, it was important to provide information to support intervention projects in historic centres. This research involves the experimental analysis of the adobe material collected from the Chellah archaeological site (Rabat-Morocco), in order to study the mechanical behaviour of this material as well as that reinforced by wood shaving. A series of mechanical tests carried out, which include compressive and tensile strength on the adobe material and the mixture adobe/wood fibre in different proportions. The improvement of the mechanical properties of the reinforced adobe, led us to a SEM study, which was carried out on the surface of the test specimens to examine the morphology and observe the interfaces of the adobe/wood mixture, as well as the state of dispersion of the fibres in the adobe mixture.

scholarly journals PHYSICAL AND MECHANICAL PROPERTIES OF JUVENILE Schizolobium amazonicum WOOD

2018 ◽  
Vol 42 (1) ◽  
Author(s):  
Graziela Baptista Vidaurre ◽  
Benedito Rocha Vital ◽  
Angélica de Cássia Oliveira ◽  
José Tarcísio da Silva Oliveira ◽  
Jordão Cabral Moulin ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Native Species ◽  
Basic Density ◽  
Physical And Mechanical Properties ◽  
Longitudinal Direction ◽  
Wood Properties ◽  
Longitudinal Contraction ◽  
The North ◽  
World Demand ◽  
Fast Growing Species

ABSTRACT Growth in world demand for wood implies a search for new fast growing species with silvicultural potential, and in this scenario for native species such as Paricá . Thus, the objective of this study was determining the physical and mechanical wood properties of the Schizolobium amazonicum species (known as Paricá in Brazil). Trees were collected from commercial plantations located in the north of Brazil with ages of 5, 7, 9 and 11 years. Four logs from trees of each age in the longitudinal direction of the trees were obtained, and later a diametrical plank of each log was taken to manufacture the specimens which were used to evaluate some physical and mechanical properties of the wood. The basic density of Paricá was reduced in the basetop direction and no difference between the radial positions was observed, while the average basic density of this wood was characterized as low. The region close to the bark showed less longitudinal contraction and also greater homogeneity of this property along the trunk, while for tangential contraction the smallest variation was found in the region near the pith. Paricá wood contraction was characterized as low. Age influenced most of the mechanical properties, where logs from the base had the highest values of mechanical strength.

Agrigento Cathedral

2015 ◽  
pp. 704-733 ◽  
Author(s):  
Liborio Cavaleri ◽  
Maria Giovanna Saccone ◽  
Maurizio Costa ◽  
Calogero Foti ◽  
Giuseppe Basile
Keyword(s):  
Mechanical Characterization ◽  
The State ◽  
Fe Model ◽  
Structural Members ◽  
Safety Level ◽  
Foundation Soil ◽  
Experimental Campaign ◽  
Extensive Damage

At present Agrigento Cathedral is affected by extensive damage that seems to be mainly due to partial slumping of the foundation soil. The chapter deals with the state of damage that affects the cathedral and the investigation carried out for the mechanical characterization of the construction, the formulation of an FE model and the assessment of the safety level with respect to the service loads and with respect to exceptional loads like seismic ones. In the chapter the details of the above investigation are discussed, consideration also being given to the monitoring carried out in order to understand whether the phenomenon affecting the cathedral is ongoing. The results of the monitoring and the experimental campaign on the structural members are described, revealing an unexpectedly low capacity with respect to service loads. Then a comparison is carried out between the response of the FE model and the experimental observations for the identification of the causes of distress. Finally possible action is discussed.

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