scholarly journals Assembly of Anisotropic Nanocellulose Films Stronger than the Original Tree

ACS Nano ◽  
2020 ◽  
Vol 14 (12) ◽  
pp. 16525-16534 ◽  
Author(s):  
Rémi Merindol ◽  
Seydina Diabang ◽  
Randy Mujica ◽  
Vincent Le Houerou ◽  
Thierry Roland ◽  
...  
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1998 ◽  
Vol 4 (4) ◽  
pp. 326 ◽  
Author(s):  
Rodney P. Kavanagh ◽  
Garry A. Webb

Populations of arboreal marsupials, small ground-dwelling mammals, reptiles and amphibians were assessed in forest before and after logging. Different levels of canopy retention were specified to estimate the effect of varying intensities of logging on these fauna. The logging treatments imposed were; unlogged, and the retention of approximately 72%, 58% and 30% of the original canopy cover. This corresponded to 62%, 52% and 21 % retention of the original tree basal area on each logged area. The objectives of the study were to determine the sensitivity of species to logging, both in terms of the intensity of the initial impact and in terms of the time to recovery following disturbance, and to develop methods for managing areas within wood production forests where special wildlife values have been identified. A total of 53 species was recorded in the 500 ha study area, only 18 (34.0%) of which were abundant enough for assessments to be made about the effects of logging. The arboreal marsupials, in particular the Greater Glider Petauroides volans, were among the species more sensitive to logging disturbance. The small, ground-dwelling mammals and the reptiles that were sampled adequately in this study appeared to be relatively unaffected by logging or they recovered quickly (most within eight years, and probably all within 10?15 years) following logging. Despite a large survey effort, insufficient data were available to assess the effects of logging on most species of frogs, although two species may have been advantaged. The species requiring management consideration include those that declined as a result of logging, but which had not recovered within eight years (the Greater Glider, the Yellow-bellied Glider Petaurus australis, the Sugar Glider P. breviceps, and the skink Niveoscincus coventryi), the species that declined in both logged and unlogged areas (the frogs Pseudophryne bibronii, Limnodynastes peronii, Geocrinia victoriana and Heleioporus australiacus), and the species for which the data were too sparse to make any assessments. It is unclear when the species most disadvantaged by integrated logging, that is, the large gliding possums, will recolonize the logged areas. The persistence of these gliders was attributed to the retention of unlogged forest within and adjacent to logged areas. This highlights the role of riparian reserves ("wildlife corridors") and filter strips in retaining residual populations of the Greater Glider and the Yellow-bellied Glider until the logged areas are suitable for recolonization, and the importance of determining the effective size for these unlogged reserves. The data were not sufficient to determine conclusively whether reduced logging intensity at the levels applied was a better option than standard logging practices for managing populations of gliding possums in these forests. The results of this study, which was conducted in a forested landscape that was multi-aged but predominantly unlogged, may not be comparable to intensively-managed forests in which there is a lower proportion of unlogged forest and where multiple logging events have occurred.


IAWA Journal ◽  
2007 ◽  
Vol 28 (2) ◽  
pp. 109-124 ◽  
Author(s):  
M. Romagnolj ◽  
M. Sarlatto ◽  
F. Terranova ◽  
E. Bizzarrj ◽  
S. Cesettj

Anatomical studies were made on the structural and decorative elements of the wooden ceiling of the 12th century Cappella Palatina in Palermo, Sicily, to identify the timbers used, analyse their likely provenance, and discuss the selection criteria used by the builders. One hundred and fifty fragments were examined. Abies sp., Pinus sp., Betula sp., Populus sp. and Fagus sylvatica were found and all are most probably from Sicily. Some of the Abies fragments probably belong to Abies nebrodensis as they have exceptionally long tracheids, very tall rays, and abundant crystals. This species was over-Iogged in the past and now only 29 trees remain in the Madonie Natural Reserve in Sicily. Abies and Pinus are found in vertieal and horizontal painted panels, while Populus, Betula and Fagus were used in smaller parts of the muqarnas (painted niches). The choice of species seems to have been related to original tree size. The large size of the Abies boles meant that quarter sawn panels could be used. Sieilian Abies was highly valued at that time for its wood quality.Special attention was paid to the problem of distinguishing partly degraded Abies and Cedrus woods. However, the scalloped torus in some sampies displayed ambiguous features and these sampies were therefore classified as Abies/Cedrus.


2005 ◽  
Vol 37 (1) ◽  
pp. 229-264 ◽  
Author(s):  
Nariyuki Minami

Let Yk(ω) (k ≥ 0) be the number of vertices of a Galton-Watson tree ω that have k children, so that Z(ω) := ∑k≥0Yk(ω) is the total progeny of ω. In this paper, we will prove various statistical properties of Z and Yk. We first show, under a mild condition, an asymptotic expansion of P(Z = n) as n → ∞, improving the theorem of Otter (1949). Next, we show that Yk(ω) := ∑j=0kYj(ω) is the total progeny of a new Galton-Watson tree that is hidden in the original tree ω. We then proceed to study the joint probability distribution of Z and Ykk, and show that, as n → ∞, Yk/nk is asymptotically Gaussian under the conditional distribution P(· | Z = n).


2021 ◽  
Vol 2090 (1) ◽  
pp. 012085
Author(s):  
Nobutoshi Ikeda

Abstract Tree graphs such as Cayley trees provide a stage to support the self-organization of fractal networks by the flow of walkers from the root vertex to the outermost shell of the tree graph. This network model is a typical example that demonstrates the ability of a random process on a network to generate fractality. However, the finite scale of the tree structure assumed in the model restricts the size of fractal networks. In this study, we removed the restriction on the size of the trees by introducing a lifetime τ (number of steps of random walks) of walkers. As a result, we successfully induced a size-independent fractal structure on a tree graph without a boundary. Our numerical results show that the mean number of offspring d b of the original tree structure determines the value of the fractal box dimension db through the relation d b — 1 = (n b — 1) -θ . The lifetime τ controls the presence or absence of small-world and scale-free properties. The ideal fractal behaviour can be maintained by selecting an appropriate value of τ. The numerical results contribute to the development of a systematic method for generating fractal small-world and scale-free networks while controlling the value of the fractal box dimension. Unlike other models that use recursive rules to generate self-similar structures, this model specifically produces small-world fractal networks with scale-free properties.


HortScience ◽  
1991 ◽  
Vol 26 (5) ◽  
pp. 495f-495
Author(s):  
Wayne J. Bourgeois ◽  
Alvin J. Adams

During the 1989 freeze, a scaffold branch irrigation freeze protection system was in operation on five-year old `Washington' navel and `Owari' satsuma trees and several younger trees of various navel orange varieties, a cold tolerant satsuma selection and other navel orange trees. Temperature dipped to a low of -11.1C, with 20 consecutive hours of -6.7C or below and 80 consecutive hours of 0C or lower. Post freeze evaluations and ratings show that an average tree survival rate of 94.6% was obtained. An average of 84.6% survival of scaffold branches and an average of 11% canopy survival was also achieved through the use of scaffold branch irrigation for freeze protection. Trunk injury ratings averaged 8.8 (scale 0-10; 0 – dead, 10 – no injury) and shoot regrowth after pruning dead wood averaged 8.0 (scale 0-10; 0 – no shoot regrowth, 10 – excellent shoot regrowth. The average percentage of the regrowth was slightly above 80% of the original tree volume prior to the freeze. Nonprotected trees sustained 100% kill and necessitated removal and reestablishment.


2019 ◽  
Vol 41 (1) ◽  
pp. 137-147
Author(s):  
Raffaele Spinelli ◽  
Rick Mitchell ◽  
Mark Brown ◽  
Natascia Magagnotti ◽  
Andrew McEwan

A chain-flail delimber-debarker-chipper (CFDDC) was adapted for treating smaller trees than normal by replacing the standard flails with lighter ones, and by reducing flail drum rotation speed. The machine produced 16 full containers (24 t each) for the standard configuration and 24 full containers for the innovative one. For each container the researchers measured: original tree mass, chip mass, time consumption and fuel use. Results indicated that the innovative setting accrued a 12% improvement on fiber recovery compared with the standard setting (control). At the same time, productivity increased by 20% and fuel consumption was reduced by 30%. Product quality was largely unaffected, with bark content remaining below the 1% threshold specification. If at all, product quality was improved through the reduction of fine particles, possibly derived from less diffused fraying. These results have triggered the real scale adoption of the new setting by contractors who participated in the study. The success of the innovative treatment is likely explained by its better alignment with the weaker structure of small trees from low-yielding stands.


2004 ◽  
Vol 129 (2) ◽  
pp. 244-249 ◽  
Author(s):  
Dale E. Kester ◽  
Kenneth A. Shackel ◽  
Warren C. Micke ◽  
Mario Viveros ◽  
Thomas M. Gradziel

The spatial and temporal pattern of noninfectious bud failure (BF) expression (BFexp) was studied during seven growing seasons in a population of `Carmel' almond trees originating from twelve commercial propagation sources. All progeny trees were grown in a single experimental site with high prevailing summer temperatures. BFexp increased continuously but irregularly in each nursery population as measured as the proportion of trees showing BF and as an average BFexp rating. Populations from the 12 nurseries represented increasing clonal generations from the original seedling tree and showed increasing levels of BF, as well as a decreasing shape value and increasing scale value derived by a failure statistics model. Models for development, distribution and hazard functions were defined for each of the 12 sources studied. Only sources from the original tree and source A demonstrated potential for commercial use. A significant correlation was found between average yearly increase in BFexp and the average daytime temperature for the previous June. The June period coincides with a specific stage in the seasonal growth cycle when vegetative buds mature.


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