scholarly journals Density Distribution in Wood of European Birch (Betula pendula Roth.)

Forests ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 445 ◽  
Author(s):  
Ewa Dobrowolska ◽  
Paulina Wroniszewska ◽  
Agnieszka Jankowska
Keyword(s):  
Density Distribution ◽  
Cross Section ◽  
Wood Density ◽  
Betula Pendula ◽  
Transverse Cross Section ◽  
Average Density ◽  
Distribution Maps ◽  
Betula Pendula Roth ◽  
Breast Height ◽  
The Cross

The aim of the presented research is to perform a comprehensive analysis of wood density variability on the longitudinal and transverse cross-section of log trees at the age of 70 to 72 years of Betula pendula Roth. and the creation of density distribution maps. Furthermore, the determination proportion of juvenile and mature wood was done. Wood density was determined with a non-destructive method using an isotopic densimeter. It was found that the wood location, both in cross-section and longitudinal section of the trunk, had a statistically significant effect on the average density of birch wood. The average density of whole logs was significantly higher than the average density at the breast height. On the cross-section, the distribution of average densities determined at the breast height, as well as on ¼ of the log height, properly depicted the distribution of average densities on the cross-section determined for the whole logs. The geographical direction (north–south) did not have a statistically significant effect on the distribution of average densities on the cross-section of the tested birch logs.

scholarly journals Polygon «Ural-carbon» (Severka)

2021 ◽  
pp. 4-14
Author(s):  
С.В. Залесов ◽  
В.В. Фомин ◽  
Е.П. Платонов ◽  
Г.А. Годовалов ◽  
К.А. Башегуров ◽  
...  
Keyword(s):  
Pinus Sylvestris ◽  
Betula Pendula ◽  
Southern Taiga ◽  
Average Density ◽  
Forest Stands ◽  
Betula Pendula Roth ◽  
Wide Range ◽  
Southern Taiga Subzone ◽  
Growing Conditions ◽  
Mature Stands

На основе баз данных лесорастительных материалов проанализированы таксационные показатели насаждений, произрастающих на территории карбонового научно-исследовательского по- лигона, расположенного в Уральском учебно-опытном лесхозе (УУОл) Уральского государственного лесотехнического университета (УГлТУ). Отмечается, что основными лесными формациями на поли- гоне являются сосняки и березняки. Доля насаждений с доминированием в составе древостоев других пород-лесообразователей невелика. Помимо сосны обыкновенной (Pinus sylvestris L.) и березы повислой (Betula pendula Roth.), другие виды произрастают, как правило, в примеси с указанными. Среди дре- востоев преобладают среднеполнотные спелые и перестойные насаждения. большинство древостоев характеризуется относительно высокими классами бонитета. Насаждения, произрастающие на террито- рии полигона, относятся к 13 типам леса, что свидетельствует о разнообразии лесорастительных усло- вий. В целом можно отметить, что видовое разнообразие древесных пород и лесорастительных условий на карбоновом научно-исследовательском полигоне УУОл УГлТУ обеспечивает возможность изучения широкого спектра вопросов депонирования углерода лесными экосистемами в условиях подзоны южной тайги Урала. The taxation indicators of plantations growing on the territory of the carbonic research polygon located in the Ural educational experimental forest enterorize (UEEF) of the Ural State Forest Engineering University were analyzed on the base of the forestry materials database. It is noted that the main forest formations on the polygons are pine and birch forest stands. The share of stands with other species of forest formers dominating in composition of forest stands is small. In addition to scots pine (Pinus sylvestris L.) and silver birch (Betula pendula Roth.), other species usually grow in admixtures with the specified. Among the stands mature and over mature stands of average density prevails. Most of the stands are characterized by relatively high bonitet classes. Plantations growing on the territory of the polygon belong to 13 types of forest, which indicates a variety of forest growing conditions. In general, it can be noted that the species diversity of tree species and forest growing conditions at the carboniferous research sity (UEEF) provides an opportunity to study a wide range of problems of carbon deposing forest ecosystems in conditions of the Southern Taiga subzone in the Urals.

Resonance in Flow-Induced Cable Vibration: Analytical Prediction and Numerical Simulation

2005 ◽  
Author(s):  
M. K. Kwan ◽  
R. R. Hwang ◽  
C. T. Hsu
Keyword(s):  
Numerical Simulation ◽  
Reynolds Number ◽  
Cross Section ◽  
Flow Direction ◽  
Cross Flow ◽  
Transverse Cross Section ◽  
Analytical Prediction ◽  
Water Flows ◽  
Flow Displacement ◽  
The Cross

Flow-induced resonance for a two-end hinged cable under uniform incoming flows is investigated using analytical prediction and numerical simulation. In this study, the fundamental mode is analyzed for simplicity. First, based on a series of physical judgments, the approximate cable trajectory is predicted — the whole cable vibrates as a standing wave, with its locus on the transverse cross-section having a convex “8”-like shape. To find the exact path, however, experiment or numerical simulation is necessary. Hence, a bronze cable at aspect ratio (length/diameter) of 100 under water flows at Reynolds number (based on cable diameter and incoming velocity) of 200 is computed. The result confirms our predictions. Moreover, it is found that the amplitude of the cross-flow displacement is much higher than that of the streamwise displacement, despite the higher streamwise fluid force. As a consequence, energy transfer from fluid to solid is maximized in the cross-flow direction.

scholarly journals A Non-Destructive Prediction Method for Wood Density Variations of Silver Birch Trees Growing in the Middle Volga Region, Russia

2020 ◽  
Vol 11 (1) ◽  
pp. 85-90
Author(s):  
Vladimir Ilyich Fedyukov ◽  
Musikhina Lydmila Anatolyevna ◽  
Maria Sergeyevna Chernova ◽  
Olga Viktorovna Tsoy ◽  
Nikita Andreyevich Magalyas
Keyword(s):  
Cross Section ◽  
Wood Density ◽  
Practical Importance ◽  
Average Density ◽  
Volga Region ◽  
Middle Volga Region ◽  
Buoyant Force ◽  
Birch Trees ◽  
Middle Volga ◽  
Non Destructive

The density of wood inside the stick varies greatly according to the diameter and height of the tree. The development of a non-destructive method of predicting an average density of wood in all specific breed stem-base density in parts of the tree is of great practical importance. For this purpose, the research was conducted to identify the patterns of wood density dynamics against the height and the diameter of birch trees growing in the conditions of the Middle Volga Region in Russia. Fourteen model birch trees (Betula pendula) were selected as research material on two plots in the plantations of the Scientific-Experimental Forest District of the Volga State University of Technology (VSUT) in the Republic of Mari El of Russia. From each felled model tree 50.0 mm cross-section discs were carved at a distance of 1.3 m from the root collar and at relative heights of 0.25H, 0.5H, and 0.75H. Prototypes in the form of 20x20x30 mm rectangular prisms (long side along the wood grain) were made from their north and south sides at a distance of 0.25R, 0.5R and 0.75R from the stem core along the NS diagonal. Density studies were conducted by measuring the density of the wood sample immersed in liquid against the buoyant force. It has been revealed that there are both differences and patterns of change in density in the longitudinal and cross-section directions of the trunk of a birch tree growing in the conditions of the Middle Volga Region in Russia. Based on the results obtained, a mathematical model of these laws has been formulated. Сlose relationship between the average density of the stick and its diameter at breast height (DBH) cross-section average density, i.e. ρtree=178.52+0.641ρdbh (r=0.922) has been revealed. By applying a well-known method of determining the density of cross-section radial core extracted from the wood by an age borer at this height, wood density of the birch trees growing in the Middle Volga Region can be calculated according to this equation.

Derivation of diameter measurements for buttressed trees, an example from Gabon

2012 ◽  
Vol 28 (3) ◽  
pp. 299-302 ◽  
Author(s):  
Alfred Ngomanda ◽  
Quentin Moundounga Mavouroulou ◽  
Nestor Laurier Engone Obiang ◽  
Donald Midoko Iponga ◽  
Jacques-François Mavoungou ◽  
...  
Keyword(s):  
Cross Section ◽  
Laser Scanning ◽  
Basal Area ◽  
3D Laser Scanning ◽  
Above Ground Biomass ◽  
Convex Shape ◽  
Tropical Tree Species ◽  
Breast Height ◽  
The Cross ◽  
Biased Estimates

Many tropical tree species have buttresses at the standard breast height (1.3 m above ground) of diameter measurement, with a presumable role in improving nutrient acquisition or tree anchorage in the ground (Newbery et al. 2009, Richter 1984). Measuring the diameter using standard dendrometrical tools such as callipers or graduated tapes, which require that the cross-section of the trunk has a convex shape, is then impossible (Nogueira et al. 2006). The recommended method in this case is to measure the diameter above the buttress (DAB), thus possibly leading to biased estimates of the basal area (West 2009), of tree above-ground biomass (Dean & Roxburgh 2006, Dean et al. 2003) and of tree growth (Metcalf et al. 2009). As an alternative, one can measure the basal area at breast height of buttressed trees, using a method that can deal with the irregular non-convex shape of the cross-section of the stem such as the Picus calliper, photogrammetry or 3D laser scanning (Badia et al. 2003, Dean 2003, Newbery et al. 2009).

A New Approach to the Demonstration of Oxidase-Localization Using Tannic Acid Or Catechin

1973 ◽  
Vol 31 ◽  
pp. 698-699
Author(s):  
V. Mizuhira ◽  
Y. Futaesaku
Keyword(s):  
Cross Section ◽  
Tannic Acid ◽  
Elastic Fiber ◽  
The Other ◽  
New Approach ◽  
Tissue Block ◽  
Active Reaction ◽  
The Cross

Previously we reported that tannic acid is a very effective fixative for proteins including polypeptides. Especially, in the cross section of microtubules, thirteen submits in A-tubule and eleven in B-tubule could be observed very clearly. An elastic fiber could be demonstrated very clearly, as an electron opaque, homogeneous fiber. However, tannic acid did not penetrate into the deep portion of the tissue-block. So we tried Catechin. This shows almost the same chemical natures as that of proteins, as tannic acid. Moreover, we thought that catechin should have two active-reaction sites, one is phenol,and the other is catechole. Catechole site should react with osmium, to make Os- black. Phenol-site should react with peroxidase existing perhydroxide.

Energy Distribution in Electron Beams

1972 ◽  
Vol 30 ◽  
pp. 568-569
Author(s):  
Tamotsu Ohno
Keyword(s):  
Electron Beam ◽  
Energy Distribution ◽  
Cross Section ◽  
Integral Curve ◽  
Electron Beams ◽  
Electron Gun ◽  
Angular Divergence ◽  
Apparent Increase ◽  
Integral Width ◽  
The Cross

The energy distribution in an electron; beam from an electron gun provided with a biased Wehnelt cylinder was measured by a retarding potential analyser. All the measurements were carried out with a beam of small angular divergence (<3xl0-4 rad) to eliminate the apparent increase of energy width as pointed out by Ichinokawa.The cross section of the beam from a gun with a tungsten hairpin cathode varies as shown in Fig.1a with the bias voltage Vg. The central part of the beam was analysed. An example of the integral curve as well as the energy spectrum is shown in Fig.2. The integral width of the spectrum ΔEi varies with Vg as shown in Fig.1b The width ΔEi is smaller than the Maxwellian width near the cut-off. As |Vg| is decreased, ΔEi increases beyond the Maxwellian width, reaches a maximum and then decreases. Note that the cross section of the beam enlarges with decreasing |Vg|.

Research in the cross-section of community psychology and global climate change: A call for action

2009 ◽  
Author(s):  
Marci Culley ◽  
Holly Angelique ◽  
Courte Voorhees ◽  
Brian John Bishop ◽  
Peta Louise Dzidic ◽  
...  
Keyword(s):  
Climate Change ◽  
Cross Section ◽  
Global Climate Change ◽  
Community Psychology ◽  
Global Climate ◽  
The Cross

Experimental Studies Of Multilayer Glass Structures On Compression, Compression With Bending And Simple Bending

2019 ◽  
pp. 22-30
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Applied Load ◽  
Experimental Studies ◽  
Strength Properties ◽  
Research Topic ◽  
Normative Values ◽  
Laminated Glass ◽  
The Cross ◽  
Experimental Values

The work of multilayer glass structures for central and eccentric compression and bending are considered. The substantiation of the chosen research topic is made. The description and features of laminated glass for the structures investigated, their characteristics are presented. The analysis of the results obtained when testing for compression, compression with bending, simple bending of models of columns, beams, samples of laminated glass was made. Overview of the types and nature of destruction of the models are presented, diagrams of material operation are constructed, average values of the resistance of the cross-sections of samples are obtained, the table of destructive loads is generated. The need for development of a set of rules and guidelines for the design of glass structures, including laminated glass, for bearing elements, as well as standards for testing, rules for assessing the strength, stiffness, crack resistance and methods for determining the strength of control samples is emphasized. It is established that the strength properties of glass depend on the type of applied load and vary widely, and significantly lower than the corresponding normative values of the strength of heat-strengthened glass. The effect of the connecting polymeric material and manufacturing technology of laminated glass on the strength of the structure is also shown. The experimental values of the elastic modulus are different in different directions of the cross section and in the direction perpendicular to the glass layers are two times less than along the glass layers.

Seasonality in the Cross-Section of Stock Returns

CFA Digest ◽  
2008 ◽  
Vol 38 (3) ◽  
pp. 55-56
Author(s):  
Kathryn Dixon Jost
Keyword(s):  
Stock Returns ◽  
Cross Section ◽  
The Cross
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