scholarly journals Formation of Annual Ring Eccentricity in Coarse Roots within the Root Cage of Pinus ponderosa Growing on Slopes

Plants ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 181 ◽  
Author(s):  
Antonio Montagnoli ◽  
Bruno Lasserre ◽  
Gabriella Sferra ◽  
Donato Chiatante ◽  
Gabriella Stefania Scippa ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Root System ◽  
Pinus Ponderosa ◽  
Cross Sectional Area ◽  
Root Segment ◽  
Mechanical Forces ◽  
Sectional Area ◽  
Coarse Roots ◽  
Cross Sectional ◽  
Branching Point

The coarse roots of Pinus ponderosa included in the cage are the ones most involved in tree stability. This study explored the variations in traits, such as volume, cross-sectional area, and radius length of cage roots, and used those data to develop a mathematical model to better understand the type of forces occurring for each shallow lateral root segment belonging to different quadrants of the three-dimensional (3D) root system architecture. The pattern and intensity of these forces were modelled along the root segment from the branching point to the cage edge. Data of root cage volume in the upper 30 cm of soil showed a higher value in the downslope and windward quadrant while, at a deeper soil depth (>30 cm), we found higher values in both upslope and leeward quadrants. The analysis of radius length and the cross-sectional area of the shallow lateral roots revealed the presence of a considerable degree of eccentricity of the annual rings at the branching point and at the cage edge. This eccentricity is due to the formation of compression wood, and the eccentricity changes from the top portion at the branching point to the bottom portion at the cage edge, which we hypothesize may be a response to the variation in mechanical forces occurring in the various zones of the cage. This hypothesis is supported by a mathematical model that shows how the pattern and intensity of different types of mechanical forces are present within the various quadrants of the same root system from the taproot to the cage edge.

The effect of unidirectional stem flexing on shoot and root morphology and architecture in young Pinus sylvestris trees

2003 ◽  
Vol 33 (11) ◽  
pp. 2202-2209 ◽  
Author(s):  
Slobodan B Mickovski ◽  
A Roland Ennos
Keyword(s):  
Pinus Sylvestris ◽  
Root System ◽  
Lateral Roots ◽  
Cross Sectional Area ◽  
External Loading ◽  
Sectional Area ◽  
Lateral Loads ◽  
Cross Sectional ◽  
Shoot Ratio ◽  
Lateral Resistance

Mechanical stresses experienced by a tree during lateral loading may cause alterations in both shoot and root growth (thigmomorphogenesis). Many of the previous studies on this subject have concentrated on shoot responses to lateral loads, while root system responses to stresses caused by external loading have been investigated only in more recent years, and even then only rarely in trees. This study presents the effect of unidirectional stem flexure of young Scots pine (Pinus sylvestris L.) on their root system morphology and architecture. Apart from the changes to the parts of the tree aboveground, unidirectional periodical flexing induced an increase in total root cross-sectional area and larger biomass allocation to the roots parallel to the plane of flexing, which in turn resulted in a larger number of major lateral roots with larger cross-sectional area in the plane of flexing. Since there were no significant differences in root to shoot ratio or the mechanical properties of wood between flexed and unflexed trees in this study, the increase in the lateral resistance in flexed trees was associated with the greater proportion of total root biomass allocated to the proximal major lateral roots, which was an adaptive mechanism for improvement of the trees' anchorage.

Tensile strength of partially filled FFF printed parts: meta modelling

2017 ◽  
Vol 23 (3) ◽  
pp. 524-533 ◽  
Author(s):  
Shahrain Mahmood ◽  
A.J. Qureshi ◽  
Kheng Lim Goh ◽  
Didier Talamona
Keyword(s):  
Mathematical Model ◽  
Tensile Strength ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Fused Filament Fabrication ◽  
Cross Sectional ◽  
Content Type ◽  
Test Pieces ◽  
Solid Part ◽  
The Cross

Purpose This paper aims to investigate the tensile strength of partially filled fused filament fabrication (FFF) printed parts with respect of cross-sectional geometry of partially filled test pieces. It was reported in the authors’ earlier work that the ultimate tensile strength (UTS) is inversely proportional to the cross-sectional area of a specimen, whereas the number of shells and infill density are directly proportional to the UTS with all other parameters being held constant. Here, the authors present an in-depth evaluation of the phenomenon and a parametric model that can provide useful estimates of the UTS of the printed part by accounting for the dimensions of the solid floor/roof layers, shells and infills. Design/methodology/approach It was found that partially filled FFF printed parts consist of hollow sections. Because of these voids, the conventional method of determining the UTS via the gross cross-sectional area given by A = b × h, where b and h are the width and thickness of the printed part, respectively, cannot be used. A mathematical model of a more accurate representation of the cross-sectional area of a partially filled part was formulated. Additionally, the model was extended to predict the dimensions as well as the lateral distortion of the respective features within a printed part using input values from the experimental data. Findings The result from this investigation shows that to calculate the UTS of a partially filled FFF part, the calculation based on the conventional approach is not sufficient. A new meta-model is proposed which takes into account the geometry of the internal features to give an estimate of the strength of a partially filled printed part that is closer to the value of the strength of the material that is used for fabricating the part. Originality/value This paper investigates the tensile strength of a partially filled FFF printed part. The results have shown that the tensile strength of a partially filled part can be similar to that of a solid part, at a lower cost: shorter printing time and lower material usage. By taking into account the geometries within a printed part, the cross-sectional area can be accurately represented. The mathematical model which was developed would aid end-users to predict the tensile strength for a given set of input values of the process parameters.

scholarly journals The Influence of Cutting Roots on the Growth and Fruiting of ‘Top Group’ Plum Cultivars

2019 ◽  
Vol 76 (2) ◽  
pp. 208
Author(s):  
Viorel MITRE ◽  
Andreea ANDRECAN ◽  
Sabin MOLNAR ◽  
Maria CODREA ◽  
Vasile MELNIC ◽  
...  
Keyword(s):  
Root System ◽  
Growth Parameters ◽  
Average Length ◽  
Cross Sectional Area ◽  
Productivity Index ◽  
Root Pruning ◽  
Sectional Area ◽  
Cumulative Yield ◽  
Cross Sectional ◽  
Mean Values

The influence of cutting roots on the growth and fruiting of ‘top group’ plum cultivars (‘Topfirst’, ‘Topfive’, ‘Toptaste’, ‘Tophit’ and ‘Topend Plus’), under the pedoclimatic conditions of Sînmihaiu Almasului, in the centre of Transylvania, Romania, in 2017-2018, was studied. The trees were grafted on Saint Julien rootstock, trained as Zahn Spindel and the orchard had a density of 1000 trees/ha. Roots were cut twice, at 40 cm distance from the trunk, in an angle of 45° and 30 cm depth, as followed: first time in the autumn during the fall of leaves, on one side of the row and the second time in spring, at blooming time, on the other side of the row. The measurements were done each year after the leaves have been fallen. There were made observations on some growth parameters (length of shoots, height of trees, trunk sectional area, the fruits and vegetative branches ratio) and fructification (average yield for 2017-2018 period, and was determined the productivity index). The treatments influenced the shoot growth, height of the trees, cumulative yield, trunk cross sectional area, the ratio of the yield to a trunk sectional area, with differences statistically assured. Root pruning reduced the average length of shoots. The longest shoots, in mean values, gave the unpruned root variant (131.0 cm). Root pruning decreased the average length of annual growth (51.1 cm). The biggest average trunk cross sectional area with the unpruned root system was obtained (58.7 cm2). Also root pruning influenced the height of the trees. The best cumulative yield was obtained in the variant of root pruning system (28.75 t/ha) followed by the unpruned root system (25.87 t/ha). Finally, root pruning increased productivity. The biggest value was registered in ‘Tophit’ in the root pruned variant (0.73 kg/cm2). The lowest value of productivity index was obtained in the unpruned system.

scholarly journals MODELING OF REDUCTION IN THE CROSS-SECTIONAL AREA OF STEEL REINFORCEMENT IN CONCRETE UNDER THE ACTION OF CORROSIVE ENVIRONMENT

2017 ◽  
Vol 21 (1) ◽  
pp. 43-49 ◽  
Author(s):  
G. A. Smolyago ◽  
A. V. Dronov ◽  
N. V. Frolov
Keyword(s):  
Mathematical Model ◽  
Reinforced Concrete ◽  
Steel Reinforcement ◽  
Cross Sectional Area ◽  
Testing Time ◽  
Corrosive Environment ◽  
Sectional Area ◽  
Cross Sectional ◽  
Rc Structures ◽  
The Cross

Process of depassivation of steel in concrete under the action of chloride corrosive environment is considered. Method of durable testing of bended reinforced concrete structures during corrosive period is described. Results of experimental research in steel reinforcement corrosion in reinforced concrete beams under the action of corrosive environment are described in the article. The diagram of corrosive potential changes during the testing time is given in the article. Measurements of corrosion potential were carried out by the corrosion analyzing instrument. Analysis of corrosive potential changes during the testing time was carried out. Main properties and features of chloride corrosion process and damages are considered. Corrosive pits on the surface of the reinforcement bars were studied. Measurements of depth and diameter of the corrosive pits were carried out. Stress-strain diagrams of steel after the corrosive period were obtained. Mathematical model of reduction in the cross-sectional area of steel reinforcement in concrete under the action of corrosive chloride environment is suggested. This model allows to consider effect of concrete cover thickness on depth of corrosion. Comparison of experimental results and theoretical calculations reveals high accuracy of corrosion damage definition by given mathematical model. The ways to use the model are suggested. The given model allows to consider corrosive damages of steel rebars by definition of cross-section area losses and may be used in calculations of strength and deformations of RC structures. It’s possible to use the model for prediction of the remaining strength life of RC structures.

Pelvic Canal Narrowing Caused by Triple Pelvic Osteotomy in the Dog

1994 ◽  
Vol 07 (03) ◽  
pp. 110-113 ◽  
Author(s):  
D. L. Holmberg ◽  
M. B. Hurtig ◽  
H. R. Sukhiani
Keyword(s):  
Postoperative Complications ◽  
Pelvic Osteotomy ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Canal Width ◽  
Operative Complications ◽  
Post Operative Complications

SummaryDuring a triple pelvic osteotomy, rotation of the free acetabular segment causes the pubic remnant on the acetabulum to rotate into the pelvic canal. The resulting narrowing may cause complications by impingement on the organs within the pelvic canal. Triple pelvic osteotomies were performed on ten cadaver pelves with pubic remnants equal to 0, 25, and 50% of the hemi-pubic length and angles of acetabular rotation of 20, 30, and 40 degrees. All combinations of pubic remnant lengths and angles of acetabular rotation caused a significant reduction in pelvic canal-width and cross-sectional area, when compared to the inact pelvis. Zero, 25, and 50% pubic remnants result in 15, 35, and 50% reductions in pelvic canal width respectively. Overrotation of the acetabulum should be avoided and the pubic remnant on the acetabular segment should be minimized to reduce postoperative complications due to pelvic canal narrowing.When performing triple pelvic osteotomies, the length of the pubic remnant on the acetabular segment and the angle of acetabular rotation both significantly narrow the pelvic canal. To reduce post-operative complications, due to narrowing of the pelvic canal, overrotation of the acetabulum should be avoided and the length of the pubic remnant should be minimized.

DETERMINATION OF THE FUNCTION OF THE ROD’S CROSS-SECTIONAL AREA USING VIBRATION EIGENFREQUENCIES

2020 ◽  
Vol 0 (4) ◽  
pp. 19-24
Author(s):  
I.M. UTYASHEV ◽  
◽  
A.A. AITBAEVA ◽  
A.A. YULMUKHAMETOV ◽  
◽  
...  
Keyword(s):  
Cross Sectional Area ◽  
Variable Cross ◽  
Sectional Area ◽  
Longitudinal Vibrations ◽  
Cross Sectional ◽  
Method Error ◽  
Various Boundary Conditions ◽  
Elastic Fixation ◽  
Crosssectional Area

The paper presents solutions to the direct and inverse problems on longitudinal vibrations of a rod with a variable cross-sectional area. The law of variation of the cross-sectional area is modeled as an exponential function of a polynomial of degree n . The method for reconstructing this function is based on representing the fundamental system of solutions of the direct problem in the form of a Maclaurin series in the variables x and λ. Examples of solutions for various section functions and various boundary conditions are given. It is shown that to recover n unknown coefficients of a polynomial, n eigenvalues are required, and the solution is dual. An unambiguous solution was obtained only for the case of elastic fixation at one of the rod’s ends. The numerical estimation of the method error was made using input data noise. It is shown that the error in finding the variable crosssectional area is less than 1% with the error in the eigenvalues of longitudinal vibrations not exceeding 0.0001.

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