Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 17

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:  ANOVA test
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
6
Artykuł dostępny w postaci pełnego tekstu - kliknij by otworzyć plik
Content available

Possibility of the production of three-layer MDF

84%
The paper proposes the production of a three-layer MDF instead one layer boards. Three-layer panels have been made from fibers of varying dimensions for the outer and the core layers. The outer layers were produced from standard fibers, while the core layer from longer and thicker fibers (of lower pulp freeness). In order to determine the optimal technological parameters in the production of three layer boards, the experimental plan was used in the study. Three factors at two levels were tested. Analysis of variance (ANOVA) was used to analyze the significance of factors. Regression coefficients and 3D contour plots were used to quantify the relationship between panel properties and test factors. Properties of obtained boards were tested according to the standard EN 622-5/2010. All selected factors within the examined range of settings had influence on MDF properties. It has been found that the best properties of the plates were 25x50x25 involving layers, the content of the glue in the outer layers of 10% and the core layer of 12% at the time of overheating of the mats 90s.
The optimal partitioning theory (OPT) predicts that a plant should allocate relatively more biomass to the organs that acquire the most limiting resource. However, variation in biomass allocation among plant parts can also occur as a plant grows in size. As an alternative approach, allometric biomass partitioning theory (APT) asserts that plants should trade off their biomass between roots, stems and leaves, and this approach can minimize bias when comparing biomass allocation patterns by accounting for plant size in the analysis. We analyzed the biomass allocation strategy of the two species: annual Setaria viridis (L.) Beauv and perennial Pennisetum centrasiaticum Tzvel from the Horqin Sandy Land of northern China by treating them with different availabilities of soil nutrient and water (added in summer and winter), and hypothesized that the two species have different patterns of biomass allocation strategy in response to different soil water content and soil nitrogen content. After taking plant size into account, the biomass allocation strategy of S. viridis and P. centrasiaticum differed in response to nitrogen and water; leaves and root:shoot ratio (RTS) of S. viridis were “true” in response to various soil nitrogen contents. The plasticity of roots was also “true” in response to fluctuation in soil water content. However, P. centrasiaticum showed a different pattern with no shift of biomass allocation strategy in response to nitrogen and water. Adjustment in organs biomass allocation pattern of S. viridis in response to nitrogen and water limitation was dramatic, this suggested that S. viridis support optimal partitioning theory (OPT). P. centrasiaticum has better tolerance to varied environments and more likely support the allometric biomass partitioning theory (APT), this characteristic may allow P. centrasiaticum to keep dominance in fragile habitats.
The significance of distance along the beach-dune transect and different moisture conditions as regards the decay of Zostera marina leaf litter was investigated in simple field experiments in three temperate, medium- to fine-quartz-sediment, sandy beaches of the Gulf of Gdańsk in Poland. 1800 replicate litterbags of freshly stranded Zostera marina leaves were placed in beach sediments at different strata and levels on each of the beaches. The litterbags were sampled after 5, 10, 50, 100 and 150 days in the field and the remaining material was then dried and weighed. Under similar conditions of sediment composition, salinity and wave inundation, ANOVA tests revealed significant differences in breakdown through time and site. Thus there were some differences in the decay process between the low and high beach. In the former, degradation proceeded rapidly in the initial stages and then stabilised, while in the latter it remained linear throughout the study period.Matter loss in each stratum was also seasonally dependent. This may, however, be more closely linked to successional changes in the chemistry and/or microflora of the beach wrack than to its physical breakdown. Differences between organic matter degradation in the high and low beaches may be explained by differences in the moisture regime and nutrient status, and not by differences in the decay processes themselves. Therefore, two decay centres were found in the beach-dune system: the low beach together with the strandline (wrack consumption 12–21 % day−1 in the warm season, and 4–10 % day−1 in the cold season) and the dune (active consumption 2–6 % day−1 in the warm season only).
Thrust force and torque in the drilling process laminated chipboard. Particleboard is a wood based composite extensively used in wood working. Drilling is the most commonly used machining process in furniture industries. The surface characteristics and the damage free drilling are significantly influenced by the machining parameters. The thrust force developed during drilling play a major role in gaining the surface quality and minimizing the delamination tendency. In this study trials were made eighteen durability tools for different values of the parameters analyzed cut. Based on the results obtained from the study, the effect of cutting parameters selected signals of axial force and torque cutting. Proposed mathematical models using ANOVA, allowing to estimate the cutting forces.
The matter of soil pollution by heavy metals caused to increase of concerns about environment. The present study has been done by the aim of investigation on zinc metal accumulation on cupressus arizonica. To achieving this goal the one-year Cupressus arizonica species seedlings were placed in vases. After the passage of each 55-day time periods from the growth of seedlings, the shoot, root and soil of seedlings were sampled. Results were studied using ANOVA test and Duncan test. The lowest concentration rate of zinc in Cupressus arizonica species organs in the first time period in the shoot and root was 5 g and 1.9 g, respectively and in the second time period in the shoot and root was 2 g and 1.6 g, respectively. Based on the researches, Cupressus arizonica species appropriate for refining zinc metal polluted soils.
The quality of the machined surface in the drilling process laminated chipboard. In this study trials were made eighteen durability tools for different values of the parameters analyzed cut. Based on the results obtained from the study, the influence of selected parameters on the cutting surface quality. Proposed mathematical models using ANOVA, allowing to estimate the surface quality in the test cutting process.The quality of the machined surface in the drilling process laminated chipboard. In this study trials were made eighteen durability tools for different values of the parameters analyzed cut. Based on the results obtained from the study, the influence of selected parameters on the cutting surface quality. Proposed mathematical models using ANOVA, allowing to estimate the surface quality in the test cutting process.
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.