Flexible Branches Research Articles

Design, Analysis, and Validation of a Passive Parallel Continuum Ankle Exoskeleton for Support and Walking Assistance

Abstract In this paper, we propose a novel passive parallel continuum ankle exoskeleton that can provide assistive torque during ankle plantar flexion. Due to the flexible branches arranged in compliance with ankle motion and shape, the compact design can also offer some vertical support. The proposed parallel mechanism consists of two types of branches. The first type is a pre-bent flexible rod, mainly used to apply assistive force/torque during ankle plantar flexion. The second type of branch consists of a bounded sphere joint, flexible rod, and bounded sphere joint (BFB), which is mainly used for support. We formulate the kinetostatic model of the BFB branch as a series of parallelizable unconstrained optimization problems to ensure efficient solvability. After that, we derive the kinetostatic model of the proposed mechanism. After calibration, the wrench error of the kinetostatic model is 9.07%. Simulation analysis based on the calibrated model shows that the designed mechanism has high supporting stiffness and low rotational stiffness. The assistive torque caused by the nonlinear rotational stiffness in the sagittal plane is similar to that of passive clutch-like mechanisms. These properties can still be maintained when the joint center changes within a small range. Besides, a walking experiment was conducted, and the results show that the proposed design can reduce gastrocnemius activity.

Physical Modelling Tests With Flexible Woody Vegetation Mimics

Riparian forests in front of dikes can dampen incoming waves and thereby contribute to flood safety. In real-scale flume experiments with live pollard willow trees (forming a 40-m-long forest), it was observed that during storm conditions, a maximum reduction of 20 % in incoming wave height could be achieved (van Wesenbeeck, et al., 2022). Notably, this amount of wave damping occurred at a water depth of 3 meters, aligning with the section of the trees with the maximum frontal-surface area. For a larger water depth, measured wave damping however declined. This is potentially partly caused by the natural tapering form of the trees. Typically, trees are characterized by smaller branch diameters and more flexible branches higher up in the canopy (McMahon & Kronauer, 1976); and flexible vegetation mimics are known to dampen less than rigid mimics due to motion (Van Veelen, T, Reeve, & Karunarathna, 2020). Hence, both the frontal-surface area and branch rigidity decrease along the height of the willow trees, potentially leading to less wave damping by the forest when subject to large waves at higher water levels.

THE EVOLUTION OF GAMBUS: TRADITIONAL TO MODERN

Gambus is supposed to have evolved from an Arabic musical instrument called Oud, which means wood; flexible branches or stalks; often referred to as a piece of wood. The Malay Peninsula, comprised of Malaysia, Brunei, Indonesia, and Singapore, is home to the lute-related term gambus. Gambus Hadramauth (Johor Gambus), Hadhrami Gambus (Malaysian Gambus), and Contemporary Gambus are the traditional varieties of Gambus in Malaysia. Gambus, which is renowned for producing music that warms and soothes the spirit, is truly accessible to people of all races and genders. Consequently, the purpose of this study is to follow the evolution of gambus in Malaysia. There are two objectives of the study, which are to study the development of gambus in terms of its physical structure, and then to identify the evolution of gambus from the perspective of its performance practice and repertoire. The research strategy involves qualitative descriptive techniques, in which data is collected through library procedures, analysed depending on the stated problem, and then the findings of the analysis are reported in writing. This study's data comes from scholarly books, theses, and periodicals. According to the findings of the researcher, the performance of gambus is significant to Malays and Muslims; even this musical instrument is viewed as a source of money for performers and producers. In addition, gambus musical instruments are more popular for entertainment purposes and are accepted and relevant to society. Keywords: Gambus, Oud, traditional musical instrument, evolution, achievement.

Реализация традиционных образов сравнения компаративных тропов с диминутивными дендронимами в русской поэзии XIX–XXI веков

The article examines the traditional images of comparison, characterizing diminutive dendronyms in the language of the Russian poetry of the 19–21st centuries, from the perspective of the relationship of ‘cultural-stereotypical (traditional) – author’s individual’. The analysis of 725 fragments from the Russian poetic works of the 19–21st centuries reveals the ways of word formation and the composition of diminutive dendronyms, as well as the composition of folk poetic, general poetic and individual author’s images of comparative tropes representing these diminutives as subjects of comparison: girl; love attraction, longing; to cry (tears), to grieve, to yearn; fertility; separation; bitter, unhappy fate, orphanhood; gold, silver; emerald; smoke; clothing; fire; pattern, mesh product; infantas by Velasquez, ermine coat; calico; fidelity. The referencedenotative features of the corresponding realia, motivating the choice of figurative associations are determined: a thin trunk, flexible branches, serrated, heart-shaped leaves, flowering trees, fruit trees. The techniques that help make stereotypical images of comparison in the Russian poetic language individualized are established: the inclusion in the composition of an extended anthropomorphic metaphor; updating by means of occasional epithets, lexical variation of the components of the trope. The stable semantic connotations of diminutive dendronyms are singled out: ‘shy’, ‘timid’, ‘meek’, ‘slender’, ‘tall’, ‘gentle’, ‘curls’, ‘braids’, ‘thin figure’, ‘beauty’, ‘breasts’, ‘captivate’, ‘innocence’, as well as the ways of their representation in poetic contexts: extended metaphors ‘autumnal withering of a tree – withering of female beauty’; memories of the lyrical hero about close people; parallelism of the images of a tree and a human condition; conventional epithets (weeping, bitter); features of the situation of a literary text. The results of the study allow us to improve the understanding of how comparative tropes with diminutive dendronyms develop dynamically in the Russian poetic language.

Peritext: A CRDT for Collaborative Rich Text Editing

Conflict-Free Replicated Data Types (CRDTs) support decentralized collaborative editing of shared data, enabling peer-to-peer sharing and flexible branching and merging workflows. While there is extensive work on CRDTs for plain text, much less is known about CRDTs for rich text with formatting. No algorithms have been published, and existing open-source implementations do not always preserve user intent. In this paper, we describe a model of intent preservation in rich text editing, developed through a series of concurrent editing scenarios. We then describe Peritext, a CRDT algorithm for rich text that satisfies the criteria of our model. The key idea is to store formatting spans alongside the plaintext character sequence, linked to a stable identifier for the first and last character of each span, and then to derive the final formatted text from these spans in a deterministic way that ensures concurrent operations commute. We have prototyped our algorithm in TypeScript, validated it using randomized property-based testing, and integrated it with an editor UI. We also prove that our algorithm ensures convergence, and demonstrate its causality preservation and intention preservation properties.

Regional variation in wood discoloration in paper birch trees

Wood discoloration was investigated in 721 paper birch (Betula papyrifera Marsh.) trees from 146 sites across the managed forest of Quebec, Canada. Discoloration was present at breast height in 85% of trees, but its impact was limited in terms of tree basal area and volume, with proportions of 6.4% and 3.6%, respectively. These two measures were strongly correlated. Discoloration changed wood appearance but had no effect on microfibril angle and modulus of elasticity. Discolored wood was nevertheless denser, probably due to the accumulation of colored extractives. Predictive models were also developed and applied to 415 711 paper birch trees from 51 689 inventory plots across the province to study regional variation. Higher proportions of discolored basal area were obtained in the southwestern areas of the province where the climate is warmer and drier. In these areas, paper birch trees are larger and, likely, support bigger branches which can cause larger columns of discoloration when broken. Lower proportions were found in eastern regions where snowfall is more abundant. Smaller, more flexible branches in trees growing in these areas could explain this result. This study confirms the feasibility of large-scale mapping of wood discoloration in standing trees based on forest inventory and climate data.

Design and experiment of the comb-brush harvesting machine with variable spacing for oil-tea camellia fruit

Oil-tea camellia tree is an important oil plant in China that has long flexible branches. The most challenging feature for the mechanized harvest of oil-tea fruits is that its flower and fruit grow synchronously. In order to improve the harvesting efficiency and avoid damaging the flower bud, a hand-held fruit harvesting machine with a variable spacing comb brush was proposed. The harvesting machine can generate three kinds of actuation to detach fruit when it runs. The main actuation results from the brushing of multiple comb fingers. The other two kinds of actuation result from the beating of comb fingers on the fruits and the branches. The finger spacing of the comb brush can be adjusted consequently through moving the spacing adjusting crossbar. Hence, when the finger spacing is smaller than the diameter of the oil-tea fruit, the fruit is brushed off, but the flower bud and leaf pass through the finger gap. When the finger spacing is bigger than the fruit diameter, the fruit stuck between the fingers is loosened to ensure the continuous operation of the machine. Nylon was used as the material of the brush finger to avoid damage, which can also reduce the overall weight. The dynamic simulation of the harvesting machine was carried out with ADAMS, and the acceleration of the front end of the comb finger and the variation of the finger spacing were analyzed. The prototype of the harvesting machine was built and tested in the field. Field experiment results showed that when the speed of the comb finger drive shaft was 480 r/min, the average harvesting percentage of oil-tea fruit was 80%, and the flower bud was seldom detached, which met the working requirements of oil-tea fruit harvesting. Keywords: oil-tea camellia fruit, harvesting machine, variable spacing, comb brush, simulation analysis DOI: 10.25165/j.ijabe.20211401.5703 Citation: Du X Q, Shen T F, Zhao L J, Zhang G F, Hu A G, Fang S G, et al. Design and experiment of the comb-brush harvesting machine with variable spacing for oil-tea camellia fruit. Int J Agric & Biol Eng, 2021; 14(1): 172–177.

Thermal performance of flexible branch heat pipe

In order to decrease the maximum temperature of the polymer tube and increase the thermal performance of the flexible heat pipe, a Y-shaped flexible branch heat pipe was designed and fabricated. Effects of structural parameters, including filling ratio of working fluid, heating power, bending angle, inclined angle, orientation angle and blockage ratio, on the thermal performance of a flexible branch heat pipe are systematically investigated. Results show that the flexible branch heat pipe has a higher cooling ability and a larger maximum heat load compared with the straight one. Flexible branch heat pipe with 15% filling ratio of working fluid has the smallest thermal resistance while the pipe with 45% filling ratio has the best anti-gravity performance. Moreover, we found that the thermal resistances of condensers for the branch heat pipe are mutually dependent. The cooling structure of the flexible branch heat pipe is changed from two condensers to one condenser when one of the condensers fails, which degrades the total cooling performance of heat pipe and increases the maximum temperature, in spite of the decrease of its total thermal resistance.

Design and experiment of the comb-brush harvesting machine with variable spacing for oil-tea camellia fruit

Oil-tea camellia tree is an important oil plant in China that has long flexible branches. The most challenging feature for the mechanized harvest of oil-tea fruits is that its flower and fruit grow synchronously. In order to improve the harvesting efficiency and avoid damaging the flower bud, a hand-held fruit harvesting machine with a variable spacing comb brush was proposed. The harvesting machine can generate three kinds of actuation to detach fruit when it runs. The main actuation results from the brushing of multiple comb fingers. The other two kinds of actuation result from the beating of comb fingers on the fruits and the branches. The finger spacing of the comb brush can be adjusted consequently through moving the spacing adjusting crossbar. Hence, when the finger spacing is smaller than the diameter of the oil-tea fruit, the fruit is brushed off, but the flower bud and leaf pass through the finger gap. When the finger spacing is bigger than the fruit diameter, the fruit stuck between the fingers is loosened to ensure the continuous operation of the machine. Nylon was used as the material of the brush finger to avoid damage, which can also reduce the overall weight. The dynamic simulation of the harvesting machine was carried out with ADAMS, and the acceleration of the front end of the comb finger and the variation of the finger spacing were analyzed. The prototype of the harvesting machine was built and tested in the field. Field experiment results showed that when the speed of the comb finger drive shaft was 480 r/min, the average harvesting percentage of oil-tea fruit was 80%, and the flower bud was seldom detached, which met the working requirements of oil-tea fruit harvesting. Keywords: oil-tea camellia fruit, harvesting machine, variable spacing, comb brush, simulation analysis DOI: 10.25165/j.ijabe.20211401.5703 Citation: Du X Q, Shen T F, Zhao L J, Zhang G F, Hu A G, Fang S G, et al. Design and experiment of the comb-brush harvesting machine with variable spacing for oil-tea camellia fruit. Int J Agric & Biol Eng, 2021; 14(1): 172–177.

(2777) Proposal to conserve the name Philippodendrum regium (Plagianthus regius) (Malvaceae) against Betula bella

(2777) Proposal to conserve the name <i>Philippodendrum regium</i> (<i>Plagianthus regius</i>) (<i>Malvaceae</i>) against <i>Betula bella</i>

The vibrational response of simulated Ginkgo biloba fruit based on their frequency spectrum characteristics.

The most effective method for harvesting forest fruit is the mechanical vibration harvesting method. During the forced vibration process, the fruit will be shed from the tree when the inertia of the fruit is greater than the fruit’s pedicel retention force. In order to study the movement response characteristics of the Ginkgo biloba fruit in depth, for a small Ginkgo biloba fruit tree, the frequency curve of the fruit tree had been obtained in this paper, based on the pulse hammer excitation method, and four resonant frequencies and four trough point frequencies, in the frequency range of 10 Hz~25 Hz, were determined as the test excitation frequency. Through a comparison test between the simulated fruit and the Ginkgo biloba fruit, both the simulated fruit and the real Ginkgo biloba fruit demonstrated good response consistency, and the results had shown that the simulated fruit could be used to replace the Ginkgo biloba fruit. The acceleration response of the resonant frequency and the trough point frequency for two test points of the two primary branches had also been analyzed. It was found that the resonant frequency caused an obvious harmonic response. For the same frequency, the fruit at some points produced a very strong vibrational response, while at other points the fruit was almost stationary. Therefore, it was difficult for a fruit tree to completely shed all its fruit through excitation at a single frequency. It was more difficult to induce a strong vibrational response of fruit on branches of higher stiffness. On the contrary, it was easier to induce a strong vibrational response on more flexible branches regardless of the resonant frequency or the trough point frequency excitation.

Impressive Arboreal Gap-Crossing Behaviors in Wild Bonobos, Pan paniscus

Most primates are arboreal, and the current context of habitat fragmentation makes gap- and road-crossing behaviors more and more common. Great apes may try to avoid behaviors such as arboreal leaping because given their size such behaviors are risky. Here, we report impressive gap-crossing by wild bonobos (Pan paniscus) in the Democratic Republic of Congo, induced by human disturbance and habitat fragmentation. We quantify the basic mechanics of leaps and arboreal landing performance in two individuals. The bonobos climbed a tree, 15 m high, and performed pronograde leaps between thin flexible branches, to grasp landing branches ca. 4 m further and below their starting point. They reached an instantaneous velocity of about 9 m · s−1. The bonobos used pendular swinging of landing branches to dissipate the kinetic energy built up during falling, requiring a grip force of about 2.5× body weight. Moreover, our results show that bonobos might be able to modulate the drag experienced during falling (up to 20% of body weight) by adjusting their posture. Apparently, bonobos evaluate the structural context to perform the best possible leap and balance the risks against the extra energetic costs involved. Further study of locomotor performance is needed to inform conservation planning, owing to the extent of habitat fragmentation due to human activities.

Implementasi Moderasi Pendidikan Islam Rahmatallil ’Alamin dengan Nilai-Nilai Islam

The moderation of Islamic education has given birth to a great civilization with an extraordinary spectrum that astonishes the world. The rules of the value of Islamic teachings that display moderation in its most beautiful format have made it very easily accepted by every human layer. Moderation in Islam has given a "guarantee" of eternal space to the teachings of this religion until the end of time. The main constancy and flexibility in the branch of Islamic teachings, makes it always able to adapt to any situation in all times and times "shalehun li kulli era wa makan". Strict basic teachings (tsawabit) and flexible branches (murunah) have provided such a wide space for the existence of ijtihad in Islam that we can be sure that this teaching has not experienced chaos. This moderation of Islam that is "built in" God promises to make this religion superior to any religion, and to any ideology produced by humans.Islam strongly opposes the anti-moderation attitude or rather extremism (ghuluw) in any form. Ghuluw's attitude will cause negative impacts and minus excesses for individuals, families, communities, countries, and the world. Extreme attitude in religion will also have a negative impact on religion itself and will cause disasters outside the religion. Extremism (ghuluwism) will cause the-religion of-Islam to be the accused party of-the emergence of harmony among local and international communities.

Aerial Manipulator Interactions With Trees for Canopy Sampling

Aerial manipulation applications involve a physical interaction between an unmanned aerial vehicle and its operating environment. This paper presents the novel application of physical coupling between an aerial manipulator and tree toward semiautonomous canopy sampling. Interactions with unconstrained objects have been studied extensively; however, trees are a complex environment with unique and naturally varying mechanical characteristics. Such interactions have not appeared in the previous literature so the effects remain unknown, thus warranting this study. First, an aircraft-tree branch interaction model is introduced using known aircraft dynamic modeling methods and a specially developed tree branch mechanical model, representing environmental disturbances to the aircraft. Coupling behavior with a range of canopy branches is investigated in both simulation, and experimentally with the aid of motion capture. The case of interactions with a swaying quasi-rigid tree stem is also explored. These respective studies have revealed station-keeping flight performance while coupled with flexible branches, and bounded environmental motion interactions where force closure does not exist. The use of conventional PID control is also validated for branch-coupled flight. Furthermore, a comparison of simulation and experimental results has shown that coupling behavior is adequately represented by mechanical effects captured in the developed tree branch model.

Structural variations in hyperbranched polymers prepared via thermal polycondensation of lysine and histidine and their effects on DNA delivery

AbstractThe successful clinical translation of nonviral gene delivery systems has yet to be achieved owing to the biological and technical obstacles to preparing a safe, potent, and cost‐effective vector. Hyperbranched polymers, compared with other polymers, have emerged as promising candidates to address gene delivery barriers owing to their relatively simple synthesis and ease of modification, which makes them more feasible for scale‐up and manufacturing. Here, we compare hyperbranched poly(amino acids) synthesised by copolymerising histidine and lysine, with hyperbranched polylysine prepared using the well‐known “ultrafacile” thermal polycondensation route, to investigate the effects of histidine units on the structure and gene delivery applications of the resultant materials. The conditions of polymerisation were optimised to afford water‐soluble hyperbranched polylysine‐co‐histidine of three different molar ratios with molecular masses varying from 13 to 30 kDa. Spectroscopic, rheological, and thermal analyses indicated that the incorporation of histidine modulated the structure of hyperbranched polylysine to produce a more dendritic polymer with less flexible branches. Experiments to probe gene delivery to A549 cells indicated that all the new hyperbranched polymers were well tolerated, but, surprisingly, the copolymers containing histidine were not more effective in transfecting a luciferase gene than were hyperbranched polylysines synthesised as established literature comparators. We attribute the variations in gene delivery efficacy to the changes induced in polymer architecture by the branching points at histidine residues, and we obtain structure–function information relating histidine content with polymer stiffness, pKa, and ability to form stable polyplexes with DNA. The results are of significance to nanomedicine design as they indicate that addition of histidine as a co‐monomer in the synthetic route to hyperbranched polymers not only changes the buffering capacity of the polymer but has significant effects on the overall structure, architecture, and gene delivery efficacy.

Enhanced adsorption of pharmaceuticals onto core-brush shaped aromatic rings-functionalized chitosan magnetic composite particles: Effects of structural characteristics of both pharmaceuticals and brushes

Core-brushes shaped chitosan/Fe3O4 composite particles (CS-MCPs) have been demonstrated applicable in the removal of pharmaceuticals due to the large amounts of functional groups on branches and heightened approachability of flexible branches to contaminants. To further enhance adsorption capacity (Qe) and pH-resistance, novel representative core-brushes shaped aromatic rings-functionalized CS-MCPs were used for adsorption of typical pharmaceuticals (norfloxacin, tylosin and diclofenac sodium (DCF)). For norfloxacin and tylosin, modified CS-MCP with polyanions (poly(sodium p-styrenesulfonate)) branches exhibited high Qe (165 mg/g and 134 mg/g, respectively); whereas for DCF, modified CS-MCP with polycations (poly(p-vinylbenzyl trimethylammonium chloride)) branches is favored (151 mg/g). Due to existence of phenyl groups on branches, Qe remained high levels in a wide pH range, proving improved pH-resistance. Considerable resistance against coexisting pharmaceuticals and inorganic ions, as well as reusability, of the adsorbents, were found. Physico-chemical analyses, instrumental characterizations and theoretical calculations demonstrated that electrostatic attraction and π-electron-containing interactions contributed to adsorption: charged ends of contaminants were fixed to oppositely charged part of branches; whereas other fragments of pharmaceutical molecules bound with π-electrons of phenyls on branches. The novel core-brush shaped biopolymer-based MCPs showed potential in water treatment and guidance for designing the brush characteristics was provided according to pharmaceutical characteristics.

New Triazole-Containing Branched Bis(dipeptidomimetic) – Switching from Self-Dimerization to Anion-Binding Properties

A triazole-containing branched bis(dipeptidomimetic) 2 using l-lysine as a flexible branching unit was synthesized and characterized. The compound was found to form weak dimers (K dim = 19 M–1) in chloroform as shown by vapor pressure osmometry (VPO) and concentration-dependent 1H NMR studies. On the other hand, the compound was capable of binding chloride and monobasic diethyl phosphate (DEP) in chloroform. Job plot analysis, MALDI-TOF mass spectrometry, and NMR titration studies revealed a 1:1 binding stoichiometry with good binding affinities (K a ≈ 640–780 M–1). Structural studies using ­ROESY NMR spectroscopy and molecular modelling on the 2–DEP complex indicated the adoption of a helix-like conformation by the host with the guest situated near the branching juncture.

Practice makes perfect: Performance optimisation in ‘arboreal’ parkour athletes illuminates the evolutionary ecology of great ape anatomy

An animal's size is central to its ecology, yet remarkably little is known about the selective pressures that drive this trait. A particularly compelling example is how ancestral apes evolved large body mass in such a physically and energetically challenging environment as the forest canopy, where weight-bearing branches and lianas are flexible, irregular and discontinuous, and the majority of preferred foods are situated on the most flexible branches at the periphery of tree crowns. To date the issue has been intractable due to a lack of relevant fossil material, the limited capacity of the fossil record to reconstruct an animal's behavioural ecology and the inability to measure energy consumption in freely moving apes. We studied the oxygen consumption of parkour athletes while they traversed an arboreal-like course as an elite model ape, to test the ecomorphological and behavioural mechanisms by which a large-bodied ape could optimize its energetic performance during tree-based locomotion. Our results show that familiarity with the arboreal-like course allowed the athletes to substantially reduce their energy expenditure. Furthermore, athletes with larger arm spans and shorter legs were particularly adept at finding energetic savings. Our results flesh out the scanty fossil record to offer evidence that long, strong arms, broad chests and a strong axial system, combined with the frequent use of uniform branch-to-branch arboreal pathways, were critical to off-setting the mechanical and energetic demands of large mass in ancestral apes.

Analysis of the apple rubbery wood disease by next generation sequencing of total RNA

Apple rubbery wood (ARW) is a disease causing abnormally flexible (rubber-like) branches in susceptible apple varieties. Despite previous efforts, the cause of the ARW remains unclear. Using Illumina next generation sequencing (NGS) of total RNA (RNA-Seq), an ARW infected apple and a healthy control were sequenced. In order to select NGS reads specific for the ARW sample, a transcriptome of the healthy apple was de novo assembled and served as a reference sequence. Reads from the ARW sample which did not align to the reference were used to search nucleotide and protein sequence databases for a possible ARW-causing pathogen. In this way, the search for a potential ARW causal agent was narrowed down to several sequences homologous to the retroviral proteins, proteins interacting with Geminivirus, Tobamovirus as well as sequences homologous to the genus Phlebovirus. Expression analysis of the genes involved in the synthesis of lignin showed decrease in expression of three out of four genes analyzed in the ARW sample.

Dendrocerus mexicali (Hymenoptera, Ceraphronoidea, Megaspilidae): Novel antennal morphology, first description of female, and expansion of known range into the U.S.

Dendrocerus mexicali has been described by Paul Dessart from a single male specimen collected in Mexico. Using 87 newly identified specimens we expand the known range to include the Southwestern United States and Florida, provide an expanded description of the species, and provide the first record of the female. We also use confocal laser scanning microscopy and in vitro hydrostatic pressure changes to investigate the functional morphology of apparently unique basally flexible antennal branches.