Physico-mechanical properties of the wood of freijó, Cordia goeldiana (Boraginacea), produced in a multi-stratified agroforestry system in the southwestern Amazon

ABSTRACT Agroforestry systems (AFSs) integrate, through sustainable practices, agricultural and forest crops for the production of wood and food, providing environmental services, and conserving biodiversity. The freijó (Cordia goeldiana) has potential for cultivation in the Amazon for timber purposes, but data on the characteristics of its wood produced in AFSs are scarce. Our objective was to determine the physical-mechanical properties and suggest technological applications of freijó wood produced in a multi-stratified AFS established in the state of Rondônia, Brazil in 1996. Agricultural and forest species were established in the AFS in double rows with 5.0-m x 2.5-m spacing. Three 19-year-old freijó trees were harvested for chemical, physical (density and dimensional stability), and mechanical (compression, static bending, Janka hardness, and shear strength) characterization of the wood. The wood presented a chemical composition similar to tropical hardwoods, was moderately heavy (582.63 kg m-3), and had high dimensional stability in comparison with other consecrated woods on the market (longitudinal, radial, and tangential retraction = 0.25, 4.27, and 6.83%, respectively). The values determined for parallel (32.32 MPa) and perpendicular compression (8.02 MPa), specific strength (55.32 MPa kg-1 m-3), parallel (2373.33 N) and perpendicular Janka hardness (2326.67 N), strength to static bending (63.5 MPa), and shear (5.94 MPa) were similar to the values observed in other high-density tropical woods grown in either monoculture plantations or natural forests. The wood under study is suitable for manufacture of high-value-added products, such as fine furniture, residential floors, musical instruments and structural pieces.

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Quality assessment of teak (Tectona grandis) wood from trees grown in a multi-stratified agroforestry system established in an Amazon rainforest area

Holzforschung ◽

10.1515/hf-2020-0082 ◽

2020 ◽

Vol 0 (0) ◽

Author(s):

Adriano Reis Prazeres Mascarenhas ◽

Marta Silvana Volpato Sccoti ◽

Rafael Rodolfo de Melo ◽

Fernando Luiz de Oliveira Corrêa ◽

Emanuel Fernando Maia de Souza ◽

...

Keyword(s):

Mechanical Performance ◽

Tectona Grandis ◽

Agroforestry System ◽

Agroforestry Systems ◽

Amazon Rainforest ◽

Natural Forests ◽

Specific Strength ◽

Structural Applications ◽

Minimum Requirements ◽

Teak Wood

AbstractThe establishment of agroforestry systems (AFS) is a consistent strategy to integrate sustainable supply of wood, food and environmental services in a single land plot. Teak (Tectona grandis Linn. F.) is an interesting option for the tree component in AFS, though there is a lack of information on its potential. This study aimed to characterize the quality of teak wood produced in an AFS regarding its technological characteristics and best end uses. Wood was sampled from a multi-stratified AFS located in the midwestern region of Rondônia state, Brazil, more specifically in a formerly deforested area of Amazon rainforest. The AFS is composed of double-ranked perennial crops and the forest component has growing space of 5.0 × 2.5 m. Physical-mechanical properties of teak wood were assessed and the results indicated its medium to high dimensional stability along with mechanical performance very close to that determined for wood from either homogeneous plantations or natural forests. Specific strength was significantly higher than some tropical wood species with higher densities. Teak wood from the AFS reached the minimum requirements for structural applications, with suitable properties to be used in the manufacture of decks, partitions and, residential flooring.

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Structure, Mechanical Performance, and Dimensional Stability of Radiata Pine (Pinus radiata D. Don) Scrimbers

Advances in Polymer Technology ◽

10.1155/2019/5209624 ◽

2019 ◽

Vol 2019 ◽

pp. 1-8

Author(s):

Jinguang Wei ◽

Fei Rao ◽

Yuxiang Huang ◽

Yahui Zhang ◽

Yue Qi ◽

...

Keyword(s):

Mechanical Properties ◽

Pinus Radiata ◽

Dimensional Stability ◽

High Performance ◽

Water Resistance ◽

Mechanical Performance ◽

Three Dimensional ◽

Radiata Pine ◽

Specific Strength ◽

Shearing Strength

Natural wood has certain advantages such as good processability and high specific strength and thus has been used for millennium as a structural material. But the mechanical performance and water resistance, particularly for fast-growing species, are unsatisfactory for high-end applications. In this study, the “new-type” scrimber technology was introduced to radiata pine (Pinus radiata D. Don) scrimbers. The structure, mechanical properties, and dimensional stability of the scrimber panels were investigated. Results showed that OWFMs as basic units of scrimber had been very even in size and superior permeability. The scrimbers exhibited a three-dimensional porous structure, and the porosity had a decrease with increasing density. Both OWFMs and densification contributed to the high performance in terms of mechanical properties and water resistance. The flexural, compressive, and short-beam shearing strength were significantly enhanced with increasing density. As the density was 0.80 g cm−3, the flexural strength (MOR) was approximately 120 MPa, much larger than many selected wood-based panels. Moreover, the water resistance and dimensional stability also were closely related to the density. At the density of 1.39 g cm−3, the water absorption rate and thinness swelling rate of the panels in boiled water were only 19% and 5.7%, respectively.

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Biological Applications of Severely Plastically Deformed Nano-Grained Medical Devices: A Review

Nanomaterials ◽

10.3390/nano11030748 ◽

2021 ◽

Vol 11 (3) ◽

pp. 748

Author(s):

Katayoon Kalantari ◽

Bahram Saleh ◽

Thomas J. Webster

Keyword(s):

Mechanical Properties ◽

Stainless Steel ◽

Bacterial Colonization ◽

Antibiotic Use ◽

Bone Cell ◽

Corrosion Properties ◽

Biomedical Implant ◽

Specific Strength ◽

Biological Functionality ◽

Bone Cell Proliferation

Metallic materials are widely used for fabricating medical implants due to their high specific strength, biocompatibility, good corrosion properties, and fatigue resistance. Recently, titanium (Ti) and its alloys, as well as stainless steel (SS), have attracted attention from researchers because of their biocompatibility properties within the human body; however, improvements in mechanical properties while keeping other beneficial properties unchanged are still required. Severe plastic deformation (SPD) is a unique process for fabricating an ultra-fine-grained (UFG) metal with micrometer- to nanometer-level grain structures. SPD methods can substantially refine grain size and represent a promising strategy for improving biological functionality and mechanical properties. This present review paper provides an overview of different SPD techniques developed to create nano-/ultra-fine-grain-structured Ti and stainless steel for improved biomedical implant applications. Furthermore, studies will be covered that have used SPD techniques to improve bone cell proliferation and function while decreasing bacterial colonization when cultured on such nano-grained metals (without resorting to antibiotic use).

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Effects of a Twin-Screw Extruder Equipped with a Molten Resin Reservoir on the Mechanical Properties and Microstructure of Recycled Waste Plastic Polyethylene Pellet Moldings

Polymers ◽

10.3390/polym13071058 ◽

2021 ◽

Vol 13 (7) ◽

pp. 1058

Author(s):

Hikaru Okubo ◽

Haruka Kaneyasu ◽

Tetsuya Kimura ◽

Patchiya Phanthong ◽

Shigeru Yao

Keyword(s):

Mechanical Properties ◽

Mechanical Performance ◽

Value Added ◽

Industrial Applications ◽

Twin Screw Extruder ◽

Screw Extruder ◽

Polymer Properties ◽

Wide Range ◽

Twin Screw ◽

Recycled Plastics

Each year, increasing amounts of plastic waste are generated, causing environmental pollution and resource loss. Recycling is a solution, but recycled plastics often have inferior mechanical properties to virgin plastics. However, studies have shown that holding polymers in the melt state before extrusion can restore the mechanical properties; thus, we propose a twin-screw extruder with a molten resin reservoir (MSR), a cavity between the screw zone and twin-screw extruder discharge, which retains molten polymer after mixing in the twin-screw zone, thus influencing the polymer properties. Re-extruded recycled polyethylene (RPE) pellets were produced, and the tensile properties and microstructure of virgin polyethylene (PE), unextruded RPE, and re-extruded RPE moldings prepared with and without the MSR were evaluated. Crucially, the elongation at break of the MSR-extruded RPE molding was seven times higher than that of the original RPE molding, and the Young’s modulus of the MSR-extruded RPE molding was comparable to that of the virgin PE molding. Both the MSR-extruded RPE and virgin PE moldings contained similar striped lamellae. Thus, MSR re-extrusion improved the mechanical performance of recycled polymers by optimizing the microstructure. The use of MSRs will facilitate the reuse of waste plastics as value-added materials having a wide range of industrial applications.

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ALLELOPATHIC EFFECTS OF ROSE WOOD, GUAVA, EUCALYPTUS, SACRED FIG AND JAMAN LEAF LITTER ON GROWTH AND YIELD OF WHEAT ( Triticum aestivum L.) IN A WHEAT-BASED AGROFORESTRY SYSTEM

Planta Daninha ◽

10.1590/s0100-83582017350100060 ◽

2017 ◽

Vol 35 (0) ◽

Cited By ~ 3

Author(s):

J. IQBAL ◽

H.A. RAUF ◽

A.N. SHAH ◽

B. SHAHZAD ◽

M.A Bukhari

Keyword(s):

Grain Yield ◽

Leaf Litter ◽

Eucalyptus Camaldulensis ◽

Dry Weight ◽

Triticum Aestivum L ◽

Agroforestry System ◽

Agroforestry Systems ◽

Growth And Yield ◽

Syzygium Cumini ◽

Allelopathic Effects

ABSTRACT Selection of tree species under agroforestry systems is crucial to sustain the productivity of a crop. In present study, allelopathic effects of the leaf litters of 5 trees named Rose wood (Dalbergia sissoo), Guava (Pisidium guajava), Eucalyptus (Eucalyptus camaldulensis), Sacred fig (Ficus religiosa) and Jaman (Syzygium cumini) species on wheat growth and yield was examined. Leaf litter of each tress species was mixed in soil with two doses @ 100 and 200 g of leaves of each species per pot. Higher shoot length, shoot dry weight, number of spikelets per spike and biological yield were recorded in 200 g sun dried Jaman (Syzygium cumini) leaves. Total number of tillers per plant and number of ears per plant were higher under the application of Eucalyptus camaldulensis leaves (200 g sun dried) as compared to other treatments. Spike length, grain yield per pot, number of grains per pot and harvest index were maximum in 200 g sun-dried Sacred fig (Ficu sreligiosa) leaves. Majority of the parameters were promoted at lower doses of leaves per pot, however, at higher doses they started inhibiting the growth and grain yield of wheat.

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Fast Preparation of High-Performance Wood Materials Assisted by Ultrasonic and Vacuum Impregnation

Forests ◽

10.3390/f12050567 ◽

2021 ◽

Vol 12 (5) ◽

pp. 567

Author(s):

Hong Yang ◽

Mingyu Gao ◽

Jinxin Wang ◽

Hongbo Mu ◽

Dawei Qi

Keyword(s):

Mechanical Properties ◽

High Performance ◽

Mechanical Tests ◽

Vacuum Impregnation ◽

Natural Forests ◽

Ultrasonic Pretreatment ◽

Fast Growing ◽

Before And After ◽

New Material ◽

Ft Ir

In the absence of high-quality hardwood timber resources, we have gradually turned our attention from natural forests to planted fast-growing forests. However, fast-growing tree timber in general has defects such as low wood density, loose texture, and poor mechanical properties. Therefore, improving the performance of wood through efficient and rapid technological processes and increasing the utilization of inferior wood is a good way to extend the use of wood. Densification of wood increases the strength of low-density wood and extends the range of applications for wood and wood-derived products. In this paper, the effects of ultrasonic and vacuum pretreatment on the properties of high-performance wood were explored by combining sonication, vacuum impregnation, chemical softening, and thermomechanical treatments to densify the wood; then, the changes in the chemical composition, microstructure, and mechanical properties of poplar wood before and after treatment were analyzed comparatively by FT-IR, XRD, SEM, and mechanical tests. The results showed that with ultrasonic pretreatment and vacuum impregnation, the compression ratio of high-performance wood reached its highest level and the MOR and MOE reached their maximums. With the help of this method, fast-growing softwoods can be easily prepared into dense wood materials, and it is hoped that this new material can be applied in the fields of construction, aviation, and automobile manufacturing.

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Effect of Neutron Irradiation on the Mechanical Properties, Swelling and Creep of Austenitic Stainless Steels

Materials ◽

10.3390/ma14102622 ◽

2021 ◽

Vol 14 (10) ◽

pp. 2622

Author(s):

Malcolm Griffiths

Keyword(s):

Mechanical Properties ◽

Stainless Steels ◽

Dimensional Stability ◽

Operating Experience ◽

Austenitic Stainless Steels ◽

High Strength ◽

Gas Production ◽

Rate Theory ◽

Fast Reactors ◽

Internal Structures

Austenitic stainless steels are used for core internal structures in sodium-cooled fast reactors (SFRs) and light-water reactors (LWRs) because of their high strength and retained toughness after irradiation (up to 80 dpa in LWRs), unlike ferritic steels that are embrittled at low doses (<1 dpa). For fast reactors, operating temperatures vary from 400 to 550 °C for the internal structures and up to 650 °C for the fuel cladding. The internal structures of the LWRs operate at temperatures between approximately 270 and 320 °C although some parts can be hotter (more than 400 °C) because of localised nuclear heating. The ongoing operability relies on being able to understand and predict how the mechanical properties and dimensional stability change over extended periods of operation. Test reactor irradiations and power reactor operating experience over more than 50 years has resulted in the accumulation of a large amount of data from which one can assess the effects of irradiation on the properties of austenitic stainless steels. The effect of irradiation on the intrinsic mechanical properties (strength, ductility, toughness, etc.) and dimensional stability derived from in- and out-reactor (post-irradiation) measurements and tests will be described and discussed. The main observations will be assessed using radiation damage and gas production models. Rate theory models will be used to show how the microstructural changes during irradiation affect mechanical properties and dimensional stability.

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Morphology of Rigid-Rod Molecular Composites: An Overview

MRS Proceedings ◽

10.1557/proc-134-511 ◽

1988 ◽

Vol 134 ◽

Cited By ~ 4

Author(s):

Stephen J. Krause

Keyword(s):

Mechanical Properties ◽

High Performance ◽

Morphological Characterization ◽

High Ratio ◽

Structure Property ◽

Chain Polymer ◽

Specific Strength ◽

Composite Systems ◽

Molecular Composites ◽

Rigid Rod

ABSTRACTRigid-rod molecular composites are a new class of high performance structural polymers which have high specific strength and modulus and also high thermal and environmental resistance. A rigid-rod, extended chain polymer component is used to reinforce a matrix of a ductile polymer with the intent of achieving a “composite” on the molecular level. After synthesis, the key to producing a molecular composite is to control morphology to disperse the reinforcing rod molecules as finely as possible in the matrix polymer. Individual rod molecules or bundles of molecular rods must have dimensions which result in a high ratio of length to width (aspect ratio) for efficient reinforcement. To achieve this, the reinforcing rod component must not phase separate at any stage of processing. Morphological characterization techniques, which can measure the orientation and dispersion (or, conversely, the degree of phase separation) of rod molecules provide the tools for correlating theoretically predicted and experimentally observed mechanical properties. Various morphological techniques which have been applied to molecular composite systems will be reviewed, including wide angle x-ray scattering and scanning and transmission electron microscopy. Structure-property correlations for molecular composite systems will be discussed with regard to models for mechanical properties. Application of new morphological techniques will also be discussed.

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The Effect of Mixing Coal with Biomass in Solid Fuel Briquettes

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.856.338 ◽

2013 ◽

Vol 856 ◽

pp. 338-342 ◽

Cited By ~ 1

Author(s):

Chin Yee Sing ◽

Mohd Shiraz Aris

Keyword(s):

Mechanical Properties ◽

Carbon Dioxide ◽

Power Plants ◽

Carbon Dioxide Emission ◽

Palm Kernel ◽

Value Added ◽

Calorific Value ◽

Fuel Properties ◽

Biomass Fuel ◽

Palm Kernel Shell

Burning fossil fuel like coal in power plants released carbon dioxide that had been absorbed millions of years ago. Unfortunately, excessive carbon dioxide emission had led to global warming. Malaysia, as one of the major exporters of palm oil, has abundant oil palm mill residues that could be converted into value-added product like biomass fuel briquettes. Fuel briquette with palm kernel shell and palm mesocarp fibre as its main ingredients showed satisfactory fuel characteristics and mechanical properties as a pure biomass fuel briquette. The effects of adding some coal of higher calorific value to the satisfactory biomass fuel briquette were focused in this study. Various coal-biomass fuel blends were used, ranging from 0wt% coal to 50wt% coal. The fuel properties and mechanical properties of pure biomass briquette and briquettes with different amount of coal added were compared experimentally. From the fuel properties tests, it was found that as the coal content in the briquette was increased, the carbon content and calorific value increased. Mechanical property tests on the fuel briquettes showed a mixture of results, with some favored higher portion of coal in the briquette for better handling, transport and storage properties while some favored greater amount of biomass.

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Wood-Polymer Composite Prepared by In Situ Synthesis of Copolymer within Wood and its Dimensional Stability

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.150-151.1 ◽

2010 ◽

Vol 150-151 ◽

pp. 1-5

Author(s):

Yong Feng Li ◽

Chi Jiang ◽

Duo Jun Lv ◽

Xiao Ying Dong ◽

Yi Xing Liu

Keyword(s):

Contact Angle ◽

Porous Structure ◽

Polymer Composite ◽

Dimensional Stability ◽

Value Added ◽

Hydroxyl Groups ◽

Wood Polymer ◽

Volume Swelling ◽

Wood Polymer Composite

In order to improve the value-added applications of low-quality wood, a novel Wood-Polymer Composite was fabricated by in-situ synthesis of copolymer from monomers within wood porous structure. The structure was characterized with SEM and FTIR, and its dimensional stability was also tested. The SEM observations showed that copolymer filled up wood pores and contact tightly with wood matrix, indicating strong interactions between them. FTIR analysis indicated that when the monomers copolymerized in situ wood porous structure, they also reacted with wood matrix by reaction of hydroxyl groups and ester groups, indicating chemical bond between the two phases, which is agreement with SEM observations. The volume swelling efficiency and contact angle of such composite were higher than those of wood, respectively, indicating good dimensional stability involving volume swelling efficiency and contact angle. Such composite could be potentially applied in fields of construction, traffic and indoor decoration.

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