Physical-mechanical properties of panels produced with corn cob particles and different types and contents of adhesives

The objective of this research was to evaluate the best type and adequate content of adhesive in low density particleboards produced with corn cob, in addition to the chemical analysis of the particles. The adhesives used were urea-formaldehyde (UF) and phenol-formaldehyde (PF) distributed in three levels (6, 9 and 12%) on the dry mass of the particles and the nominal density was 0.60 g.cm-3. Regarding the water absorption and swelling properties, no significant differences were found between treatments. The mean value calculated for the IE 24 h was 37.07%, being above the minimum limit stipulated by the standard. The modulus of rupture (MOR) and modulus of elasticity (MOE), were influenced by the tested factors. All particleboards met the requirements of the standard norm. For internal adhesion there was a significant effect only for the type of adhesive factor, with the particleboards produced with PF showing the highest means. For the compression property there was no effect of the factors tested. In general, the dimensional stability of the particleboards was below the minimum required by the standard, but the mechanical properties met all requirements.

The issue of the information technology and technical terminology translatability from English into Russian: the typology and the nominative density levels

The 21st century is characterized by its rapid scientific and technological advancement. Digital and technical inventions have resulted in computer globalization which caused the necessity of adequate translation of different kinds of English-language technical documentation, manuals, software products, etc. The article deals with the recent tendencies in translation and interpretation studies showing increasing interest to the ways English scientific and technical texts are rendered into Russian. The article considers the peculiarities of translating the scientific and technical vocabulary in the information technologies sphere and provides a typology of the English terms. Non-equivalent vocabulary is considered to be the most serious communication challenge. The authors identify the basic typical features of the computer discourse vocabulary, analyze the correlation between its nominal density and translatability level. The findings indicate that the ratio between the nominal density and translatability level of linguistic concepts is inversely proportional. The academic originality of the study involves the classification of technical and computer terms, as well as comparing nominal density and translatability levels. The article focuses on the most applicable English-language computer terms translation techniques, such as calquing, substantiation, generalization, semantic development, descriptive translation, antonymic translation, replacement and transformation of parts of a sentence. Pointing out that both linguistic and extralinguistic factors affect the translation solution choice, the authors believe that the correct approach to the translation process guarantees a successful intercultural communication.

Comparative Analysis of Properties of Particleboards Made from Corn Cobs at Varying Proportions of Clay Soil

Particles of dried corn cobs were employed for manufacture of cement bonded particleboards. Two types of clay soil (red and white) were used as supplement with cement to manufacture cement bonded particleboards. The production of the boards was done at varying proportions of 50/50/0, 50/40/10, 50/30/20, 50/20/30, 50/10/40 and 50/0/50 for (corn/cement/clay) in weight to weight basis while the other considerable production factors like nominal density and curing agent percentage remained constant at 1.30 g/cm3 and 3%. The chemical composition of the soil such as pH, organic carbon, organic matter, total nitrogen, and exchangeable bases were determined. Its impact on physical and mechanical properties such as density, water absorption, thickness swelling, modulus of rupture and modulus of elasticity were also investigated The results of the analysis of variance shows that all considerable production factors for the cement bonded particleboards were significant at 5% level of probability except clay soil type for density. The results show that cement bonded particleboard made of red clay soil with higher content of exchangeable bases proves better outstanding performance in density, strength and dimensional properties than the white clay soil. Among the cement bonded particleboards made at varying proportions. It was discovered that boards of 50/20/30 (corn/cement/clay) had better strength properties than others. Also, the boards made at the proportions of 50/40/10, 50/10/40 and 50/30/20 (corn/cement/clay) were better dimensionally stabled in moisture exposure but weak in strength. The outcome of this study may serve as a guideline for any manufacturer who intends to use clay soil as supplement for production of particleboards. Keywords: Cement, particleboard, clay soil, corn cobs, strength, variance

EVALUATIOM OF PHYSICAL AND MECHANICAL PROPERTIES OF PARTICLEBOARD PRODUCED FROM WOOD OF Cupressus torulosa IN MIXTURE WITH Pinus taeda

The objective of this work was to evaluate the quality of particleboard produced with 100% of wood of Cupressus torulosa and in different mixing proportions with Pinus taeda. The experimental panels were produced with wood particles of Cupressus torulosa/Pinus taeda, in proportions of 100/0%, 80/20%, 60/40%, 40/60%, 20/80% and 0/100%, totaling six treatments. The panels were produced with nominal density of 0.75g/cm³, 8% urea-formaldehyde resin and 1% paraffin emulsion. The quality of the panels was evaluated by water absorption and swelling thickness 2 and 24 hours, static bending (MOE and MOR), perpendicular tension (internal bonding) and screw withdrawal. The comparative evaluations of the results of this research, with the Pinus taeda, others species referenced in the literature, and normative requirements of EN 312-2003 for commercial panels, indicated great potential of the wood of Cupressus torulosa for the particleboard production.

Impact of kaolin on physicomechanical properties of density-graded cement bonded paperboards

Paperboards of thickness 0.6 cm with densities of 0.8, 0.9, and 1.0 g/cm3 were produced from waste papers mixed with cement and kaolin. Printing and corrugated waste papers were employed in the proportions of 50.0/25.0/25.0, 50.0/37.5/12.5, and 50.0/12.5/37.5 (paper/cement/kaolin), respectively. The dimensional and strength properties of the boards were investigated. The values obtained range from 0.40 to 0.94 g/cm3, 51.19 to 68.10%, 0.14 to 3.10%, 0.01 to 1.69 Nmm-2, and 119.98 to 567.32 Nmm-2 for observing the density, water absorption, thickness swelling, modulus of rupture, and modulus of elasticity, respectively. The board of proportion 25/25 of kaolin/cement was densest with high strength. As the nominal density and kaolin content were increased from 12.5 to 37.5%, an increase was observed in density and strength properties. Similarly, as the proportion of kaolin and cement content were increased, the rate of moisture uptake to cavity decreased. This study shows that boards from printing papers were more dimensionally stable than corrugated papers. It revealed that printing papers could be better raw material for manufacture paperboard than corrugated papers. Information provided in this study could be used as a guideline for the manufacture of paperboard reinforced with kaolin as an additional constituent for quality improvement.

Ecological panels as an alternative for waste from mechanical processing of Amazonian species

The wood residues resulting from the operational phases in companies in the forestry market are normally considered by-products and, therefore, are discarded or reused for energy production, however, this material has a greater potential, such as the generation of new products through agglutination, which may generate a new segment in the wood industry, causing competition between products of native and planted species. This research aimed to develop agglomerated panels using residues of two tree species from the Amazon (Dinizia excelsa Ducke and Manilkara huberi (Ducke) Chevalier) and a mixture of commercial Amazonian species of high density, with the purpose of greater added value and a possible solution to reduce the negative environmental impacts of carbon emissions. The experimental design consisted of three treatments with five repetitions in each. Experimental panels were produced with a nominal density of 0.80 g/cm³, using castor oil-based resin with 10% percentages. The panels were pressed with a pressure of 10 MPa, temperature of 100ºC and with a pressing time of 10 minutes. The evaluations of the results obtained were compared with the ANSI A208.1 / 2009 standard and with the literature on agglomerated panels of tropical species. In physical properties, the panels showed compliance with the values found in the literature, however, they are outside the standard of the norm. Regarding the mechanical properties, the MOR values classify the panels in the medium to high density standard in accordance with the standard. The results of the MOE are superior to those of the existing literature, with emphasis on the perpendicular traction that presents values consistent with the literature. The machining evaluations carried out according to ASTM D 1666-11 / 2011, show a good quality in the finish. In general analysis and in compliance with the regulations, all panels have economic viability and potential for industrialization.

Extending the concept of background to soil gas: natural radon concentrations in soils of Campania region.

<p>Radon is an ubiquitous radioactive gas proceeding from the decay of some radionuclides, mostly abundant in igneous rock and volcanic soils; it is the main source of natural radiation to which human beings are exposed during their life. Campania, a region located on the south-western sector of the Italian peninsula, has a territory mostly characterized by the presence of volcanic lithotypes and sediments. <br>An empirical method was applied to determine the concentration of Rn-222 in soils of Campania region by using radiometric  and compositional data recorded in two extensive different environmental prospecting campaigns completed in 2003 and 2015, respectively.</p><p>Radiometric surveys were carried out with a nominal density of 1 station per 5 sqkm with a GRS-500 portable scintillometer produced by Scintrex Ltd (Ontario, Canada); topsoil samples were collected at 3535 sites regularly spread across the whole regional area with a nominal density of 1 sample per sqkm. Samples destinated to chemical analyses were analysed by ICP-MS after an aqua regia digestion at the ACME Analytical Laboratories Ltd (now Bureau Veritas) in Vancouver, Canada.  </p><p>Specifically, the concentrations of  U, Th and K  in topsoil samples  and the activity (gamma radiation) generated by the decay of U-238, Th-232 and K-40 (expressed as Bq) at  each measurement station were used as proxies in order to determine the variation of Rn-222 flux from the ground and to estimate the distribution pattern of geogenic radon potential (GPR) across the region.</p><p>The use of a sequence of specific equations led to estimate the terrestrial gamma dose rate (nSv/h) at 1 m above the ground surface starting from both datasets and, therefore, allowed the generation of the Rn-222 flux and GPR maps for the whole regional territory.</p><p>Both Radon flux and GPR raster maps were produced by mean of some specific geospatial elaborations and the estimated values were compared among them and validated trough the completion of some field measurements.</p>

Sunflower (Helianthus Annuus) Stalks as Alternative Raw Material for Cement Bonded Particleboard

Sunflower stalks (Helianthus annuus) were studied as an alternative raw material for cement bonded particleboard. Experimental cement bonded particleboards measuring 500 mm × 500 mm × 12 mm with nominal density of 1300 kg/m3 were produced using different ratios of sunflower stalk particles with wood. Properties of the cement bonded particleboards evaluated include water absorption, thickness swelling, screw withdrawal strength and bending properties. Results of the study showed that the addition of small amount of sunflower stalks in the production of cement bonded particleboard does not significantly influence the properties tested. Inclusion of more stalks in the mixture significantly decreases mechanical properties and raises thickness swelling and water absorption values of the cement bonded particleboard. Results indicate that boards which include a small amount of sunflower stalks provide properties required by the standards for general purpose-use cement bonded particleboards.

Erosion in a Melt-Infiltrated SiC/SiC Ceramic Matrix Composite

Erosion phenomenon of ceramic matrix composites (CMCs), attributed to their unique architectural configurations, is markedly different from conventional monolithic ceramic counterparts. Prior to further integration of CMCs into hot-section components of aeroengines subject to erosive environments, their erosion behavior needs to be characterized, analyzed, and formulated. The erosion behavior of a 2D woven melt-infiltrated (MI) SiC/SiC CMC was assessed in this work as a function of variables such as particle velocity and size. The erosion damage was characterized using appropriate analytical tools such as optical and scanning electron microscopy (SEM). A phenomenological erosion model was developed for SiC/SiC CMC material systems with respect to the kinetic energy of impacting particles in conjunction with nominal density, matrix hardness, and elastic modulus of the SiC/SiC CMCs. The model was in reasonable agreement with the experimental data.

Size at Maturation, Spawning Variability and Fecundity in the Queen Conch, Aliger gigas

The queen conch (Aliger gigas) resource is one of the most important in the Caribbean. While aspects of queen conch reproduction have been studied, e.g., size—at—maturity, spawning season, and density—based Allee effects, there is little information on other important aspects. From 210 lipped queen conch collected off southwest Puerto Rico, histological examination of gonads showed that 50% maturation occurred at 9 mm lip thickness. Experimental caged queen conch held on a natural spawning ground were monitored across the spawning season to evaluate fecundity and its variability across individuals and between nominal density treatments (2,000 vs 143 conch/ha). Near daily monitoring identified all egg masses to specific females, and all egg masses were retained to calculate the number of eggs. Conch in the low—density treatment produced more and larger egg masses over a longer spawning season than those in the high—density treatment. Within each density treatment, individual fecundity varied by a factor of 6. The maximum fecundity estimated was 22 million, the maximum number of egg masses spawned was 25, and the largest single egg mass contained 1.48 million eggs. Variability in fecundity was largely driven by length of the individual spawning season, but this may in turn have been dependent on the degree of maturation of females at the start of the spawning season. These results emphasize the importance of allowing queen conch to mature and further grow in lip thickness to ensure sufficient spawning to sustain reproductive capacity. This experimental approach could be used to assess variations in fecundity based on size (length, biomass) and age (lip thickness).