scholarly journals Influence of structural reinforcements on the twist-to-bend ratio of plant axes: a case study on Carex pendula

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Steve Wolff-Vorbeck ◽  
Olga Speck ◽  
Thomas Speck ◽  
Patrick W. Dondl
Keyword(s):  
Mathematical Models ◽  
Cross Sections ◽  
Torsional Rigidity ◽  
Biological Evolution ◽  
Strong Increase ◽  
Herbaceous Plant ◽  
Fibre Reinforcement ◽  
Vascular Bundles ◽  
Flower Stalk

AbstractDuring biological evolution, plants have developed a wide variety of body plans and concepts that enable them to adapt to changing environmental conditions. The trade-off between flexural and torsional rigidity is an important example of sometimes conflicting mechanical requirements, the adaptation to which can be quantified by the dimensionless twist-to-bend ratio. Our study considers the triangular flower stalk of Carex pendula, which shows the highest twist-to-bend ratios ever measured for herbaceous plant axes. For an in-depth understanding of this peak value, we have developed geometric models reflecting the 2D setting of triangular cross-sections comprised of a parenchymatous matrix with vascular bundles surrounded by an epidermis. We analysed the mathematical models (using finite elements) to measure the effect of either reinforcements of the epidermal tissue or fibre reinforcements such as collenchyma and sclerenchyma on the twist-to-bend ratio. The change from an epidermis to a covering tissue of corky periderm increases both the flexural and the torsional rigidity and decreases the twist-to-bend ratio. Furthermore, additional individual fibre reinforcement strands located in the periphery of the cross-section and embedded in a parenchymatous ground tissue lead to a strong increase of the flexural and a weaker increase of the torsional rigidity and thus resulted in a marked increase of the twist-to-bend ratio. Within the developed model, a reinforcement by 49 sclerenchyma fibre strands or 24 collenchyma fibre strands is optimal in order to achieve high twist-to-bend ratios. Dependent on the mechanical quality of the fibres, the twist-to-bend ratio of collenchyma-reinforced axes is noticeably smaller, with collenchyma having an elastic modulus that is approximately 20 times smaller than that of sclerenchyma. Based on our mathematical models, we can thus draw conclusions regarding the influence of mechanical requirements on the development of plant axis geometry, in particular the placement of reinforcements.

scholarly journals Influence of Structural Reinforcements on the Twist-to-bend Ratio of Plant Stems

2020 ◽  
Author(s):  
Steve Wolff-Vorbeck ◽  
Olga Speck ◽  
Thomas Speck ◽  
Patrick Dondl
Keyword(s):  
Cross Sections ◽  
Torsional Rigidity ◽  
Biological Evolution ◽  
Strong Increase ◽  
Fibre Reinforcement ◽  
Vascular Bundles ◽  
Element Analysis ◽  
Epidermal Tissue ◽  
Mechanical Quality

Abstract During biological evolution, plants have developed a wide variety of body plans and concepts that enable them to react or adapt to changing environmental conditions. Their morphological-anatomical and mechanical adaptations to conflicting conditions are especially interesting. A good example is the trade-off between flexural and torsional rigidity, as represented by the dimensionless twist-to-bend ratio. We have developed geometric models of a plant tissue reflecting the 2D situation of triangular cross-sections comprising of a parenchymatous matrix with vascular bundles surrounded by an epidermis and analysed them by using mathematical models (finite element analysis) to measure the effect of either reinforcements of the epidermal tissue or fibre reinforcements such as collenchyma and sclerenchyma on the twist-to-bend ratio. The change from an epidermis to a covering tissue of corky periderm increases both the flexural and the torsional rigidity and decreases the twist-to-bend ratio. Furthermore, additional fibre reinforcement strands in a parenchymatous ground tissue lead to a strong increase of the flexural and a weaker increase of the torsional rigidity and thus resulting in a marked increase of the twist-to-bend ratio. Within the developed model, a reinforcement by 49 sclerenchyma fibre strands or 24 collenchyma fibre strands is optimal in order to achieve high twist-to-bend ratios. Dependent on the mechanical quality of the fibres, the twist-to-bend ratio of collenchyma-reinforced axes is noticeably smaller, with collenchyma having an elastic modulus that is approximately 20 times smaller than that of sclerenchyma.

scholarly journals BANANA LEAVES QUALITY OF Musa balbisiana Colla. AND Musa paradisiaca L. BASED ON ANATOMICAL STRUCTURE

2015 ◽  
Vol 2 (1) ◽  
pp. 361 ◽  
Author(s):  
Maryani _ ◽  
Puput Pratiwi
Keyword(s):  
Cross Sections ◽  
Vascular Bundle ◽  
Nutrient Content ◽  
Anatomical Structure ◽  
Vascular Bundles ◽  
Musa Balbisiana ◽  
Musa Paradisiaca ◽  
Cell Layers ◽  
Banana Leaves

<p>Indonesia is the main centre of banana biodiversity. Banana is preferred because of its high nutrient content and economical value. Besides, banana leaves, particularly from “Klutuk” banana (Musa balbisiana Colla.) is also well-known used as traditional wrapper of cakes and foods. The objective of this research was to know and to compare the anatomical structure of Musa balbisiana Colla. and Musa paradisiaca L. leaves, and their anatomical characters as quality indication of banana leaves used as cakes and foods wrapper. Cross sections of banana leaves were prepared using free hand section and paraffin embedding methods. Leaf clearing method was used to prepare upper and lower epidermal tissue slides. Parameters used were the arrangement of cells/tissues, length and width of vascular bundles, mesophyll thickness, the thickness of schlerenchyma tissue, the number of laticiferous and tanin cells, and stomata indexs. The data were analyzed using Analysis of Variance (Anova) continued by Duncan test at level 5%. The results showed that the anatomical structure of M.balbisiana Colla. and M. paradisiaca L. leaves consisted of epidermis, hypodermis, mesophyll, and vascular bundles. The supporting tissues were composed of sclerenchyma located at upper and lower side of vascular bundle. The number of cell layers composing upper and lower hypodermis; stomata number, stomata index, the length and width of stomata; the thickness of vascular bundles; the thickness of layers composing adaxial and abaxial mesophyll; the thickness of schlerenchyma layers and width of schlerenchyma tissue at vascular bundle as well as laticiferous and tannin cell were found differently between M. balbisiana Colla. and M. paradisiaca L. The values of meshophyll thickness, length and width of vascular bundle, the thickness of schlerenchyma tissue, the number of laticiferous cells and the number of tanin cells were higher for M. paradisiaca L than in M. balbisiana Colla. The smaller the thickness of schlerenchyma layers and the width of schlerenchyma tissue at vascular bundle as well as the less number of laticiferous and tannin cells were assumed to be correlated with the good quality of M. balbisiana Colla leaves as foods and cakes wrapper. </p><p><strong>Keywords</strong>: anatomy, banana leaves, Musa balbisiana Colla., Musa paradisiaca L.</p>

Do changes in light direction affect absorption profiles in leaves?

2010 ◽  
Vol 37 (5) ◽  
pp. 403 ◽  
Author(s):  
Craig R. Brodersen ◽  
Thomas C. Vogelmann
Keyword(s):  
Cross Sections ◽  
Incident Light ◽  
Monochromatic Light ◽  
Diffuse Light ◽  
Spongy Mesophyll ◽  
Light Regimes ◽  
Direct Light ◽  
Direct Measurements ◽  
Leaf Level

Leaf anatomy plays a functional role in propagating light through the leaf; palisade mesophyll has been shown to facilitate the channelling of collimated light deeper into the spongy mesophyll. Direct measurements of the propagation of diffuse light into the leaf, however, are absent. Using chlorophyll fluorescence imaging of leaf cross-sections, we measured light absorption profiles in leaves under direct (collimated), diffuse and low-angle monochromatic light. Low-angle and diffuse light was absorbed closer to the irradiated surface than direct light perpendicular to the surface. The shapes of internal absorption profiles indicated that leaves were influenced by the directional quality of the incident light. In addition, absorption profiles revealed that leaves were not simple light absorbing objects and that cellular anatomy influences the direction of light travelling into the mesophyll. These findings also suggest a mechanism for previously measured differences in leaf level photosynthesis under opposing light regimes.

Constraint-Based Reverse Engineering From Ultrasound Cross-Sections

1997 ◽  
Author(s):  
Jai Menon ◽  
Ranjit Desai ◽  
Jay Buckey
Keyword(s):  
Reverse Engineering ◽  
Cross Sections ◽  
Biomedical Applications ◽  
Engineering Application ◽  
Volume Data ◽  
Cross Sectional ◽  
Reverse Engineer ◽  
Network Bandwidth ◽  
Complex Topology

Abstract This paper extends the “cross-sectional” approach for reverse engineering, used abundantly in biomedical applications, to the mechanical domain. We propose a combination of “projective” and cross-sectional algorithms for handling physical artifacts with complex topology and geometry. In addition, the paper introduces the concept of constraint-based reverse engineering, where the constraint parameters could include one or more of the following: time, storage (memory, disk-space), network bandwidth, Quality of Service (output-resolution), and so forth. We describe a specific reverse-engineering application which uses ultrasound (tilt-echo) imaging to reverse engineer spatial enumeration (volume) representations from cross-sectional data. The constraint here is time, and we summarize how our implementation can satisfy real-time reconstruction for distribution of the volume data on the internet. We present results that show volume representations computed from static objects. Since the algorithms are tuned to satisfy time constraints, this method is extendable to reverse engineer temporally-varying (elastic) objects. The current reverse engineering processing time is constrained by the data-acquisition (tilt-echo imaging) process, and the entire reverse engineering pipeline has been optimized to compute incremental volume representations in the order of 3 seconds on a network of four processors.

scholarly journals Evaluation of Forecasts of a Convectively Generated Bore Using an Intensively Observed Case Study from PECAN

2018 ◽  
Vol 146 (9) ◽  
pp. 3097-3122 ◽  
Author(s):  
Aaron Johnson ◽  
Xuguang Wang ◽  
Kevin R. Haghi ◽  
David B. Parsons
Keyword(s):  
Cross Sections ◽  
Turbulent Mixing ◽  
Weather Research And Forecasting ◽  
Cold Pool ◽  
Model Errors ◽  
Near Surface ◽  
Cold Pools ◽  
Convection Model

Abstract This paper presents a case study from an intensive observing period (IOP) during the Plains Elevated Convection at Night (PECAN) field experiment that was focused on a bore generated by nocturnal convection. Observations from PECAN IOP 25 on 11 July 2015 are used to evaluate the performance of high-resolution Weather Research and Forecasting Model forecasts, initialized using the Gridpoint Statistical Interpolation (GSI)-based ensemble Kalman filter. The focus is on understanding model errors and sensitivities in order to guide forecast improvements for bores associated with nocturnal convection. Model simulations of the bore amplitude are compared against eight retrieved vertical cross sections through the bore during the IOP. Sensitivities of forecasts to microphysics and planetary boundary layer (PBL) parameterizations are also investigated. Forecasts initialized before the bore pulls away from the convection show a more realistic bore than forecasts initialized later from analyses of the bore itself, in part due to the smoothing of the existing bore in the ensemble mean. Experiments show that the different microphysics schemes impact the quality of the simulations with unrealistically weak cold pools and bores with the Thompson and Morrison microphysics schemes, cold pools too strong with the WDM6 and more accurate with the WSM6 schemes. Most PBL schemes produced a realistic bore response to the cold pool, with the exception of the Mellor–Yamada–Nakanishi–Niino (MYNN) scheme, which creates too much turbulent mixing atop the bore. A new method of objectively estimating the depth of the near-surface stable layer corresponding to a simple two-layer model is also introduced, and the impacts of turbulent mixing on this estimate are discussed.

scholarly journals Accuracy and Reproducibility of Acoustic Tomography Significantly Increase with Precision of Sensor Position

2017 ◽  
Vol 2 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Steffen Rust
Keyword(s):  
Risk Assessment ◽  
Norway Spruce ◽  
Cross Sections ◽  
Acoustic Tomography ◽  
Model Operator ◽  
Sensor Position ◽  
Complex Shapes ◽  
Source Of Error ◽  
Sensor Positions

Acoustic tomograms are widely used in tree risk assessment. They should be accurate,repeatable and comparable between consecutive measurements. Previous work has failed to address the effects of different approaches to record sensor positions, operators and models of tomograph on the resulting tomograms.In this study, three operators used the two most common sonic tomographmodels to measure seven cross-sections of Norway spruce trees, whichwere felled after the measurement. We evaluated the effects of model, operator, and different approaches to measure sensor positions on the quality of the tomograms.The largest source of error was the position of sensors, affectingestimated stress wave velocity, the shape of the tomogram, and the sizeof the defect.To produce accurate and repeatable tomograms of trees with complex shapes,it is essential to measure the sensor positions precisely.

Image processing algorithms in the assessment of grain damage degree

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Wojciech Maliga ◽  
Włodzimierz Dudziński ◽  
Magdalena Łabowska ◽  
Jerzy Detyna ◽  
Marcin Łopusiewicz ◽  
...  
Keyword(s):  
Image Processing ◽  
Cross Sections ◽  
Three Dimensional ◽  
Sample Volume ◽  
Three Dimensional Model ◽  
Time Intervals ◽  
Damage Degree ◽  
Grain Damage ◽  
Analyse Sample

Abstract Objectives The paper presents preliminary results on the assessment of algorithms used in image processing of the grain damage degree. The purpose of the work is developing a tool allowing to analyse sample cross-sections of rye germs. Methods The analysis of the grain cross-sections was carried out on the basis of a series their photos taken at equal time intervals at a set depth. The cross-sections will be used to create additional virtual cross-sections allowing to analyse the whole sample volume. The ultimate plan is to generate two cross-sections perpendicular to each other. Based on volumetric data read from the sample section, a three-dimensional model of an object will be generated. Results The analysis of model surface will allowed us to detect possible grain damage. The developed method of preparing the research material and the proprietary application allowed for the identification of internal defects in the biological material (cereal grains). Conclusions The presented methodology may be used in the agri-food industry in the future. However, much research remains to be done. These works should primarily aim at significantly reducing the time-consuming nature of individual stages, as well as improving the quality of the reconstructed image.

The Genetic Algorithm

2019 ◽  
pp. 154-178
Author(s):  
Burcu Adıguzel Mercangöz ◽  
Ergun Eroglu
Keyword(s):  
Genetic Algorithm ◽  
Mathematical Models ◽  
Portfolio Optimization ◽  
Optimization Problem ◽  
Optimization Problems ◽  
Biological Evolution ◽  
Research Field ◽  
Risk Level ◽  
Important Research ◽  
Portfolio Optimization Problem

The portfolio optimization is an important research field of the financial sciences. In portfolio optimization problems, it is aimed to create portfolios by giving the best return at a certain risk level from the asset pool or by selecting assets that give the lowest risk at a certain level of return. The diversity of the portfolio gives opportunity to increase the return by minimizing the risk. As a powerful alternative to the mathematical models, heuristics is used widely to solve the portfolio optimization problems. The genetic algorithm (GA) is a technique that is inspired by the biological evolution. While this book considers the heuristics methods for the portfolio optimization problems, this chapter will give the implementing steps of the GA clearly and apply this method to a portfolio optimization problem in a basic example.

New morphological and anatomical data on the genus Fuernrohria (Apiaceae)

Phytotaxa ◽  
2020 ◽  
Vol 429 (1) ◽  
pp. 48-56
Author(s):  
BARIŞ BANİ ◽  
DUDU ÖZLEM MAVİ İDMAN
Keyword(s):  
Cross Sections ◽  
Leaf Sheath ◽  
Distribution Area ◽  
Morphological Description ◽  
Leaf Segment ◽  
Vascular Bundles ◽  
Anatomical Data ◽  
Micromorphological Characters ◽  
First Time ◽  
Stem Leaf

In this study, morphological and anatomical data (including fruit micromorphological characters) of the genus Fuernrohria were studied and compared with the related genera Grammosciadium, Caropodium and Vinogradovia. The morphological description of Fuernrohria setifolia, which is the only known species in the genus, is expanded. Photos of inflorescences, infructescences and leaves of the species taken from the wild are provided. Leaf segment and mericarps are illustrated, and also the distribution area of the genus is mapped. Anatomical features of root, stem, leaf sheath, leaf segment and fruit are presented with photographs of cross sections for each of them. Vegetative anatomical characteristics of the species and micromorphological description of fruit are given and exhibited for the first time in the present study. The results show that two important diagnostic characters for Fuernrohria are determined for the first time as “shape and size of commissural vittae in mericarps” and “number of vascular bundles in leaf cross section”.

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