Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 19

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych:  black locust
help Sortuj według:

help Ogranicz wyniki do:
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
The aim of this research was to investigate formaldehyde content in and volatile organic compounds release from particleboards produced from fibrous chips. The object of the tests were panels produced from fibrous chips of black locust Robinia Pseudoacacia L. and willow Salix Viminalis L., as well as from typical industrial particles. The results show that formaldehyde content in the panels produced from willow fibrous chips is similar to the content in the panels made of industrial particles. The concentration of total volatile organic compounds measured after 4 weeks of storage is significantly lower than the required by the existing regulations.
4
86%
The aim of the research was to investigate the face screw withdrawal resistance of panels produced from fibrous chips of willow Salix Viminalis L. and black locust Robinia Pseudoacacia L. A series of laboratory 3-layer panels were produced from fibrous chips as well as from industrial particles. The results were compared to commercial industrial panel performance. The investigation shows that the panels from black locust have lower screw withdrawal resistance in comparison with the industrial panel. In the case of higher density willow panel the screw withdrawal resistance was better than that of the industrial panel.
Within the framework of work on the anatomical structure and durability features of wood, as well as analyses of radial growth, a preliminary analysis was carried out in regard to variation in the heartwood within Black locust trees. The research was carried out in three stands of straight-stemmed trees in western Poland. The variation displayed by the heartwood around its circumference and the eccentricity of the trunks was characterised with reference to: the heartwood radial index (HRI), the cross-sectional shape factor for heartwood (CSsf) and the pith eccentricity index (PEcc). The results confirmed a relationship between the degree of variation around the circumference of the heartwood and the mean age of the stands, while at the same time making clear the high level of differentiation in radial variation at the level of the individual tree. The findings suggest that the fertility of the habitat does not exert much of an influence on the generation of heartwood in Black locust trees. No statistically significant relationship was obtained when the circumferential variation of the heartwood was set against the total height or diameter at breast-height. Only in the case of crown length, and then only at the Wołów site, was there a moderate negative correlation with the coefficients of circumferential variation.
The objective of the study was to monitor the activity of soil enzymes related to C, N and P transformations as well as some chemical parameters as influenced by an area covered with black locust (Robinia pseudoacaciaL). Samples of typical brown soil were collected from the surface layer of a cultivated field (0 - 24 m, every 2 m) adjacent to a planted area under black locust trees. Activities of the enzymes of the C-cycle (β-glucosidase), N-cycle (nitrate reductase, arginine deaminase and urease), P-cycle (alkaline and acid phosphatases) and dehydrogenases were determined colorimetrically. Moreover, pH in KCl, CORG, NTOT, PE-R and N-NH₄⁺ determinations were made. Significant differentiation of chemical parameters and enzymatic activity (except for acid phosphatase activity) was noted with increasing distance from black locust trees. CORG, NTOT concentrations and dehydrogenases, alkaline phosphatase, urease andβ-glucosidase activitiesdecreased with the distance fromR. pseudoacaciawhile PE-Rand N-NH₄⁺contents as well as nitratere ductase and deaminase arginine positively correlated with the distance from the black locust stand.
Due to its extraordinary hardness, decorative appearance and possible small dimensions, black locust wood is assumed to be an excellent material for strip parquetflooring. The favourable colour changes achieved by controlled steam treatment further increased the utilization potential of this material. Flooring was installed on a student dormitory stair landing in heavy use. Due to the flooring’s very high exposure, 5 years was considered a long enough period to compare the different face layer materials during in-service test. Oil was used as a coating to avoid the remarkable protecting effect of hard film-forming varnishes (acrylic, etc.) against abrasion. Besides the flooring turning grey (all face layers no matter what treatment), only some delamination occurred at certain places after five years in service.The laboratory test results for abrasion resistance, dimensional changes and deformation were analysed. Additionally, the Brinell-Mörath hardness after indoor service and the abrasion due to indoor service were analysed. In terms of abrasion resistance, dimensional changes and deformation, no essential differences werefound between the oil-treated and untreated black locust wood on the one hand, and the control oak specimen on the other. Long-term tests showed that, after 5 years in service, the Brinell-Mörath-hardness decreased considerably for all the testedmaterials. The type of section and the presence of wide rays influenced the roughness and the waviness of the surface after indoor service.
Samples of leaves, stems and whole plant of tetraploid Robinia pseudoacacia harvested at four different growth stages (first rapid growth, slow growth, second rapid growth, and leaf-colour changing) were analysed for chemical composition and in situ disappearance of protein and fibre using the nylon bag technique. The crude protein content was the highest in leaves, followed by whole plant, and the lowest in stems, while the opposite trend was found for dry matter, NDF, and ADF. Moreover, the crude protein content of the three plant parts decreased during maturation. Effective degradability of crude protein was higher for stems (519.0 g kg-1) than for whole plant (353.6 g kg-1) and leaves (270.4 g kg-1). Effective degradability of ADF was significantly higher in leaves than in the whole plant and stems. Ruminal disappearance of nutrients in the three plant parts was higher during the first rapid growth stage than at later stages.
Fuel properties of woody biomass plant descending from urban areas. The presented work includes research on woody biomass plant descending from pruning operations in Poznań urban area. Studies were carried out on deciduous wood (Populus tremula L., Acer platanoides L., Robinia pseudoacacia L.) and coniferous wood (Pinus sylvestris L.). The aim of this study was to investigate the basic fuel properties of the wood materials obtained from the maintenance of urban green areas.
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.