scholarly journals Effects of termal treatment on the physical properties of Buchenavia sp. (branquilho) wood

2022 ◽  
Vol 22 (1) ◽  
pp. 95-103
Author(s):  
Laysa Teles Vollbrecht ◽  
Adriano Reis Prazeres Mascarenhas ◽  
Rafael Rodolfo de Melo ◽  
Maúcha Fernanda de Mota Lima ◽  
Ricardo Pereira Soteil ◽  
...  

Abstract This work aimed to evaluate the effect of heat treatment on the physical properties of wood from Buchenavia sp. The heat treatments were carried out at temperatures of 180 °C and 200 °C for 2 h. Apparent density (AD), basic density (BD), porosity (Ф), mass loss, longitudinal (LS), radial (RS), tangential (TS) and volumetric (VS) shrinkages and anisotropic factor (AF) were determined. The lowest values of basic density (0.67 g cm-3), apparent density (0.77 gcm-3), and porosity (43.3%) were observed for the wood treated at a temperature of 200 °C. Mass losses increased with increasing temperature and the highest values were observed under the condition of 200 °C (9.3%). The LS and AF was not affected by heat treatments. The mean values for RS (3.1%), TS (5.1%), and VS (9.1%) were reduced after the performance of heat treatments at temperatures of 180°C and 200°C, which did not differ from each other. The thermal treatments were able to reduce the dimensional instability of Buchenavia sp. Thermal treatments enhance the use of less prestigious Amazonian woods in the civil construction market.

2019 ◽  
Vol 142 (1) ◽  
pp. 321-329 ◽  
Author(s):  
Ákos Lakatos ◽  
István Csarnovics

AbstractNowadays, aerogel materials are some of the lightest thermal insulation materials available on the construction market; they are produced by the mixing of polymers with solvents since they create a gel. Insulated fibrous-enhanced forms are the most frequently used ones. The type, which is used for thermal insulation, is usually produced by mixing the glass fiber net with the liquid–solid solution. The present paper talks about the structural modifications caused by heat treatment of the aerogel-reinforced with fiberglass. The aerogel probes were subjected to thermal annealing, and once they got isothermal heat treatments for weeks at 70 °C, moreover, untreated samples were subjected to stepwise thermal treatments between 100 and 250 °C for 1 day. Both the heat treatments were executed in dryer equipment under atmospheric air. Changes both in the structure and in chemical bonds of the untreated and annealed samples were followed. Raman spectra have been obtained for the samples. The structural changes have an influence on the studied material as well as in thermal properties. The structural and thermal properties were put under investigation after executing heat treatments on them. Jumps in the thermal conductivity could be connected with some structural changes. Due to the annealing intensity of the peaks connected with Si–O, crystalline SiO is increased, while CH, CH2, CH3, –OH and others are decreased.


2011 ◽  
Vol 2 (2) ◽  
pp. 48-52
Author(s):  
Gaddafi Ismaili ◽  
Badorul Hisham Abu Bakar ◽  
Khairul Khuzaimah Abdul Rahim

 Aras had been selected and tested in small clear specimens. Sampling of test specimens are made from three sections of the tree bole namely from bottom, middle, and top parts. This paper looks into the information of strength properties from three sections of sampled. The strength properties test required are the modulus of rupture, modulus of elasticity and compression stress parallel to grain. Meanwhile, the physical properties' test referred to moisture content and basic density. The testing conducted in two different conditions of the trees, which were referred to green and air-dry condition. It was found that the average mean values for modulus of rupture, modulus of elasticity and compressive stress parallel to grain tested at green condition were 47.52N/mm2, 6358.56N/mm2 and 22.42N/mm2 respectively meanwhile at air-dry condition were 70.49N/mm2, 8217.64N/mm2 and 34.07N/mm2 respectively. Meanwhile, the average mean values for moisture content at green condition were 83.34% whilst at the air-dry condition were 12.33%. Basic density remains unchanged from both conditions.


2014 ◽  
Vol 38 (4) ◽  
pp. 1281-1292 ◽  
Author(s):  
Luis Alberto Lozano ◽  
Carlos Germán Soracco ◽  
Vicente S. Buda ◽  
Guillermo O. Sarli ◽  
Roberto Raúl Filgueira

The area under the no-tillage system (NT) has been increasing over the last few years. Some authors indicate that stabilization of soil physical properties is reached after some years under NT while other authors debate this. The objective of this study was to determine the effect of the last crop in the rotation sequence (1st year: maize, 2nd year: soybean, 3rd year: wheat/soybean) on soil pore configuration and hydraulic properties in two different soils (site 1: loam, site 2: sandy loam) from the Argentinean Pampas region under long-term NT treatments in order to determine if stabilization of soil physical properties is reached apart from a specific time in the crop sequence. In addition, we compared two procedures for evaluating water-conducting macroporosities, and evaluated the efficiency of the pedotransfer function ROSETTA in estimating the parameters of the van Genuchten-Mualem (VGM) model in these soils. Soil pore configuration and hydraulic properties were not stable and changed according to the crop sequence and the last crop grown in both sites. For both sites, saturated hydraulic conductivity, K0, water-conducting macroporosity, εma, and flow-weighted mean pore radius, R0ma, increased from the 1st to the 2nd year of the crop sequence, and this was attributed to the creation of water-conducting macropores by the maize roots. The VGM model adequately described the water retention curve (WRC) for these soils, but not the hydraulic conductivity (K) vs tension (h) curve. The ROSETTA function failed in the estimation of these parameters. In summary, mean values of K0 ranged from 0.74 to 3.88 cm h-1. In studies on NT effects on soil physical properties, the crop effect must be considered.


1991 ◽  
Author(s):  
Robin Stevenson ◽  
Earl G. Brewer ◽  
Kraig Malstrom ◽  
H. Daniel Pursel

2017 ◽  
Vol 41 (1) ◽  
Author(s):  
Delmar Santin ◽  
Marcelino Breguez Gonçalves Sobrinho ◽  
Angélica de Cássia Oliveira Carneiro ◽  
Eliziane Luiza Benedetti ◽  
Nairam Félix de Barros

ABSTRACT In mate crop, the commercial part consists of leaves and thin branches, while the large branches (LB) are considered unused residues and left in the field, although they may have potential for use as energy. The objective of this paper was to evaluate the influence of phosphorus fertilization and harvest interval in productivity of mate large branches and in their physical and energetic properties, as well as in derived briquettes. In a seven-year-old plantation, doses of 0, 20, 40, 80, 160 and 320 kg.ha-1 of P2O5 were applied considering harvest intervals of 12, 18 and 24 months. Dry mass, average diameter, P content, and physical and energetic properties of LB were determined. With LB, after its transformation into particles and briquetting, physical and energetic properties were determined, as well as P availability in soil. The phosphorus fertilization increased LB productivity in larger harvest intervals, increasing the amount of energy produced per unit of area, but did not change basic density and gross calorific value of wood. Mate harvest intervals did not affect the apparent density and calorific value of briquettes produced by LB. LB harvested at intervals of 18 and 24 months produced wood with higher basic density and gross calorific value. LB or briquettes have adequate energetic and physical properties, being technically a plant residue with great potential for use as energy.


2021 ◽  
Vol 9 (04) ◽  
pp. 304-313
Author(s):  
Jocelyn Constant Yapi ◽  
◽  
Jean Bedel Fagbohoun ◽  
Zranseu Ange Benedicte Deffan ◽  
Elvis Gbocho Serge Ekissi ◽  
...  

Peroxidase (POD) associated with the browning of fresh-cut fruits and vegetableswas extracted from purple skin eggplant(Solanum melongena L.) and characterised using reliable spectrophotometric methods. Maximal POD activity was found at 35 °C and pH 6.0 with guaiacol as the substrate. The enzyme was stable at his optimal temperature (35 °C) and hisat pH stability was in the range of 5.6 - 6.6.Peroxidase retained its full activity in the presence of ion K+, Cu2+, Na+, Pb2+ and Ba2+ but were inhibited strongly by the ion Fe2+ and Mg2+ and the reducing agents as sodium thiosulfateand ascorbic acid. Effect of heattreatment on eggplant peroxidase showed that D-values decreased with increasing temperature, indicating faster peroxidase inactivation at higher temperatures.At 60 °C, the D-values ranged from 20.42 to 54.24 min. Hence, heat treatment at 60 °C for 30 min reduced browning of eggplant fruit.These data can be used to predict prevention of browning in the purple skin eggplantby thermal inactivation and the use of chimical agents onthe enzyme.


2008 ◽  
Vol 13 (1-2) ◽  
pp. 113 ◽  
Author(s):  
F. K. GATES ◽  
B. DOBRASZCZYK

The aim of this review is to illustrate how physical properties are important to food processing and quality. Three food products, flakes, porridge and bread, in addition to oat groats are used to show the influence of water and heat-treatments on the mechanical properties. The hydrothermal history of ingredients is shown to affect product quality. Water acts as a plasticiser and solvent in these foods, whilst heat modifies the conformation and interactions of macromolecular components. Structure as well as chemical composition is shown to govern texture.;


2014 ◽  
Vol 1611 ◽  
pp. 171-176
Author(s):  
W.S. Gónzalez-Gómez ◽  
J. May-Crespo ◽  
P. Quintana ◽  
A. May-Pat ◽  
F. Avilés ◽  
...  

ABSTRACTRocks are composed of minerals, bounding matrix, cracks and pores. The study of changes in the physical properties of rocks as a function of heat treatment is relevant to various engineering and industrial applications. The effect of thermal damage on the compression, strength, ultimate compression strain, color and loss of mass of two different limestones extracted from the Yucatan Peninsula is studied. Different thermal treatments are applied by heating the sample from room temperature up to 600°C, with steps of 100°C. The results show a high correlation between the heat transport characteristics, mechanical properties, content of organic matter and the presence of carbonates and iron oxides in each type of limestone rock.


2016 ◽  
Vol 30 (2) ◽  
pp. 237-243 ◽  
Author(s):  
Karolina Szulc ◽  
Andrzej Lenart

Abstract The paper presents an influence of raw material composition and technological process applied on selected physical properties of food powders. Powdered multi-component nutrients were subjected to the process of mixing, agglomeration, coating, and drying. Wetting liquids ie water and a 15% water lactose solution, were used in agglomeration and coating. The analyzed food powders were characterized by differentiated physical properties, including especially: particle size, bulk density, wettability, and dispersibility. The raw material composition of the studied nutrients exerted a statistically significant influence on their physical properties. Agglomeration as well as coating of food powders caused a significant increase in particle size, decreased bulk density, increased apparent density and porosity, and deterioration in flowability in comparison with non-agglomerated nutrients.


2000 ◽  
Vol 15 (3) ◽  
pp. 614-620 ◽  
Author(s):  
M. Mora ◽  
E. Martínez ◽  
J. C. Díez ◽  
L. A. Angurel ◽  
G. F. de la Fuente

Bi-2212 cylindrical rods were obtained using a laser-induced directional solidification system. Although as-grown Bi-2212 samples are well textured, they do not exhibit superconducting behavior and, as a result, need further heat treatments. The modifications taking place during annealing were analyzed in the present work, in particular with respect to the evolution of the microstructure with the annealing time and the phase content. Diffusion processes in which the Bi-2212 phase grows along the thickness of the platelets take place during annealing. The presented results show that the physical properties of these samples improve during the initial approximately 60 h of annealing and that they remain constant thereafter.


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