Undulating Shape Research Articles

2A2-B03 飛行ビークルのための対地適応システムの開発 : ジャミング転移現象を利用した機構(飛行ロボット・メカトロニクス(2))

A balloon like mechanism enclosing powder exploiting jamming transition is developed for a landing gear of aerial vehicles on rough terrain. The hardness of the balloon can be drastically controlled changing the enclosed air pressure. An aerial vehicle that has this mechanism can fit undulated terrain by its softness and prevent tumble by its hardness. This function needs only one D.O.F. A controllable mechanism is manufactured using rubber sheet, coffee powder, a pump and air valves. A quad rotor helicopter model with this mechanism is developed. Takeoff, landing, and fitting on undulated ground shape are demonstrated using the manufactured model.

Generalized models for rock joint surface shapes.

Generalized models of joint surface shapes are the foundation for mechanism studies on the mechanical effects of rock joint surface shapes. Based on extensive field investigations of rock joint surface shapes, generalized models for three level shapes named macroscopic outline, surface undulating shape, and microcosmic roughness were established through statistical analyses of 20,078 rock joint surface profiles. The relative amplitude of profile curves was used as a borderline for the division of different level shapes. The study results show that the macroscopic outline has three basic features such as planar, arc-shaped, and stepped; the surface undulating shape has three basic features such as planar, undulating, and stepped; and the microcosmic roughness has two basic features such as smooth and rough.

Encyonema mirabilis, Cymbella olgae and C. cognata: new diatom species from Lake Baikal

Three new diatom species in the family Cymbellaceae, Encyonema mirabilis, Cymbella olgae and Cymbella cognata were described from the littoral zone of Lake Baikal, Russia. Small size, dense striae and deep areolae differentiate these taxa from closely related species. Areolae in C.cognata have a undulate, double-pore and horseshoe-like shape.

A new version of a rumpling predictive model in thermal barrier coatings

In many cases the modelling of rumpling evolutions appears as a necessary step in the development of a TBC life prediction methodology. The analytical model initiated by Balint and Hutchinson (2005) is further developed and improved, incorporating two new possibilities: 1. In addition to the 2D roughness description (with a single cosine model of the undulation), a 3D undulation shape is now available (a double cosine model), following a similar approach; 2. Both the 2D and the 3D undulation models are modified in order to allow any kind of thermomechanical cyclic loading applied by the substrate, with different maximum temperatures, including the possibility of oxidation, associated growth strains and oxide yielding during the temperature transients. The successive modifications in the model are evaluated by successively comparing the rumpling responses at four maximum temperatures. A parametric analysis reveals the significant role of the initial undulation geometry on the influence of several material factors like the bond coat creep resistance or the presence or not of the martensitic transformation during the temperature cycle. Moreover the initial geometry also greatly affects the difference of rumpling predicted under cyclic oxidation and isothermal oxidation.

Editorial on the Topical Issue “Neutron Biological Physics”

This special issue brings together a number of original research papers focused on recent developments in biological membrane and membrane model studies by a variety of state-of-the-art biophysical methods. Neutron scattering is especially well represented. Our knowledge of biological macromolecules and their interactions is based on the application of physical methods, ranging from classical thermodynamics to recently developed techniques for the detection and manipulation of single molecules. The role of neutron diffraction and spectroscopy techniques in improving this knowledge has been outstanding and the potential for future developments is remarkable. Many challenges remain for neutron techniques to answer the questions raised by molecular and cellullar biology. The following pages give a flavour of the progress in the field. A report [1] describes time-resolved small angle scattering of light-induced changes in chloroplast thylakoid membranes. In the context of surface functionalization, the structure in different ionic conditions of sodium hyaluronan grafted at a solid-liquid interface was observed by neutron reflectivity [2]. A review of membrane protein studies [3] addresses the difficulties encountered by providing information on the properties of surfactants used to solubilise membrane proteins for contrast variation studies by neutron small angle scattering, as well as on membrane protein deuterium labelling strategies. The thought-provoking Zaccai neutron resilience and site-specific hydration dynamics in a globular protein are discussed in [4]. Membrane raft model structures with tuneable compositions were characterised by neutron diffraction and reflectivity [5], while raft dynamics in large uni-lamellar vesicles in interaction with beta amyloid peptide was observed by the neutron spin echo method combined with small angle scattering [6]. The bending stiffness of biological membranes as determined by neutron spin echo is also presented [7]. Two contributions [8, 9] report on undulation dynamics and shape fluctuations, respectively, in lipid vesicles as a function of lipid composition and other parameters observed by neutron spin echo in combination with other methods like small angle scattering and light scattering. Elastic incoherent neutron scattering was applied to compare dynamics in natural membranes extracted from hyperthermophile and mesophile bacteria in the context of their different biological activities [10]. A molecular dynamics simulation study discusses macromolecular resilience as was defined from neutron spectroscopy experiments. The underlying mechanisms of bioprotection by sugars were explored by using data from Infrared Spectroscopy, Molecular Dynamics simulations, Small Angle X-ray Scattering and Calorimetry [11]. Time resolved small angle X-ray scattering in combination with other biophysical methods can contribute immensely to the study of protein dynamics and a paper presents a new set-up, including a microfluidic continuous-flow mixer, which provided results on unfolding dynamics. And the project of a neutron dynamics data bank is presented in a Perspectives article [12]. The aim of the bank will be to make neutron dynamics data on biological systems widely available to the scientific community.

Different ageing conditions on cementitious roofing tiles reinforced with alternative vegetable and synthetic fibres

This paper discusses the effects of different ageing conditions on the mechanical and physical characteristics of cementitious roofing tiles reinforced with sisal and newsprint pulps, sisal strand fibre and polypropylene (PP) fibre. Roofing tiles with undulate shape were produced by a slurry de-watering and pressing technique. They were subjected to three distinct ageing conditions: fast carbonation, accelerated ageing cycles and fast carbonation plus accelerated ageing cycles. Fast carbonation did not improve the maximum load (ML), limit of proportionality (LOP), toughness and maximum deflection but did decrease their water absorption, apparent porosity and air permeability; however, after 50 heat and rain accelerated ageing cycles, it was ineffective in maintaining the mechanical properties (ML, LOP, toughness and deflection) of the tiles reinforced with vegetable fibres. The refined sisal pulp fibres led to roofing tiles with slightly higher LOP, toughness and maximum deflection than those reinforced with newsprint pulp fibres. PP fibres significantly improved the mechanical performance (ML, LOP, toughness and deflection) of the roofing tiles in relation to sisal strand fibres. The accelerated ageing cycles were effective in promoting severe degradation on the roofing tiles with sisal strand fibres, while the tiles reinforced with PP fibres were practically unaffected.

The effect of fibre chemical treatment on the steel fibre/cementitious matrix interface

This paper aims to study the interfacial bonding between steel fibres and cement-based matrix. The fibres were treated chemically using a zinc phosphate conversion to achieve enhanced bonding with the mortar matrix. In order to gain a better perspective on the effect of chemical treatment different fibre parameters were considered in this research, such as the fibres shape, length and diameter. In this respect, single-sided fibre pullout tests were conducted on treated as well as on as received (untreated) fibres of hooked-end, straight and undulated shape. The analysis of the experimental results revealed that the fibre shape is of great importance since it contributes to mechanical interlocking that prevail during the pullout of the fibres. Chemical treatment was also shown to play an important role on the fibre–matrix interface especially when mechanical interlocking is absent. Treated fibres exhibited a modified surface with a rough topology caused by precipitation of ZnPh crystals on the fibre. Optimum fibre configuration for maximum pullout performance can be chosen based on the fibre surface contact area, since the pullout load and pullout energy is directly related to this property.

Hydrodynamic perception in true seals (Phocidae) and eared seals (Otariidae)

Pinnipeds, that is true seals (Phocidae), eared seals (Otariidae), and walruses (Odobenidae), possess highly developed vibrissal systems for mechanoreception. They can use their vibrissae to detect and discriminate objects by direct touch. At least in Phocidae and Otariidae, the vibrissae can also be used to detect and analyse water movements. Here, we review what is known about this ability, known as hydrodynamic perception, in pinnipeds. Hydrodynamic perception in pinnipeds developed convergently to the hydrodynamic perception with the lateral line system in fish and the sensory hairs in crustaceans. So far two species of pinnipeds, the harbour seal (Phoca vitulina) representing the Phocidae and the California sea lion (Zalophus californianus) representing the Otariidae, have been studied for their ability to detect local water movements (dipole stimuli) and to follow hydrodynamic trails, that is the water movements left behind by objects that have passed by at an earlier point in time. Both species are highly sensitive to dipole stimuli and can follow hydrodynamic trails accurately. In the individuals tested, California sea lions were clearly more sensitive to dipole stimuli than harbour seals, and harbour seals showed a superior trail following ability as compared to California sea lions. Harbour seals have also been shown to derive additional information from hydrodynamic trails, such as motion direction, size and shape of the object that caused the trail (California sea lions have not yet been tested). The peculiar undulated shape of the harbour seals' vibrissae appears to play a crucial role in trail following, as it suppresses self-generated noise while the animal is swimming.

Shakedown on Thermal Barrier Coating and Simply Analytic Model

A simply analytic model is developed base on wrinkle geometry model. The three concentric circles are adopted to represent top coat, oxide coat and bond coat of thermal barrier coating, and then shakedown analysis is established based on the model. A numerical model has been given base on wrinkle geometry model in a thermal barrier coating system, and the model on static shakedown analysis is developed by finite element method. Shakedown limit of thermal barrier coating is calculated for various undulation shape and thermal grown oxide. The simply analytic results and numerical results are approximate for undulation shape is not very irregular. The simply analytic model is convenient for calculating shakedown limit of thermal barrier coating.

Experimental Characterization and Modeling of Bending Properties of Woven Fibrous Preforms

The properties of final composite parts depend on properties of dry preforms often being formed over doubly-curved shapes. In this case the fibrous preforms exhibit intricate large deformations, including shear, tension, and bending modes. Although the bending stiffness of fibrous materials is small, in shaping of preforms, when wrinkling occurs, its influence is important, not negligible and responsible for the wrinkles shape. Because of the structural and mechanical peculiarities, the experimental determination of bending properties of fibrous materials is rather complex, and there is no unique generally adopted test. A set of cantilever tests was chosen to be carried out in this study, in the form of sequence of different loading cases for one material that permits to reveal the eventual non-linear and non-elastic behavior of the material in bending. The tests were realized for glass fabrics with different types of weaving patterns and different areal weights. The effect of these parameters on the bending response is studied. The analysis of the data on bending of fabrics and bending of yarns, extracted from fabrics with the preserved undulated shape, is performed as well. The regions of the deformed specimens characterized by the largest scatter of experimental data are identified and analyzed. Besides, the analytical model based on corrugated plates theory, taking into account the undulated architecture of fabrics, is employed to characterize its bending properties, and to make a future comparison with the test results.

DESICCATION STRESS CAUSES STRUCTURAL AND ULTRASTRUCTURAL ALTERATIONS IN THE AEROTERRESTRIAL GREEN ALGA KLEBSORMIDIUM CRENULATUM (KLEBSORMIDIOPHYCEAE, STREPTOPHYTA) ISOLATED FROM AN ALPINE SOIL CRUST1.

Klebsormidium crenulatum (Kütz.) Lokhorst (Klebsormidiophyceae, Streptophyta) isolated from an alpine soil in Tyrol, Austria, was experimentally exposed to desiccation under various relative air humidities (RH 5, 75, and >95%, ambient air 55%-60%). The effects on the structure and ultrastructure of K. crenulatum after 1, 4, or 7 d of desiccation at 5, 75, and >95% RH were investigated. The cross walls were deformed to an undulated shape, and the cell diameter was reduced to ∼60% of the control. Regardless of the RH applied, in all cases the cytoplasm appeared denser compared to that of liquid-culture-grown cells. Electron-dense particles with diameters of 0.4 μm-0.8 μm were observed in the cytoplasm, likely representing lipid droplets. The chloroplasts of desiccated samples contained a large number of plastoglobules. The number and appearance of mitochondria were not visibly altered, as also verified by 3,3' dihexyloxacarbocyanine iodine (DIOC6 ) staining. The amphiphilic styryl dye FM 1-43 resulted in staining of the plasma membrane in cells from liquid culture. In 7 d desiccated samples, a marked fluorescence is seen in ∼40%-50% of the cells, which were dead. Actin microfilaments (MFs) were drastically disrupted after desiccation; only dotlike actin batches remained. These results demonstrate that flexibility of the cell walls and maintenance of the key organelles play a key role in the tolerance of desiccation stress in K. crenulatum.

Cu6Sn5 and Cu3Sn lntermetallics Study in the Sn-40Pb/Cu System during Long-term Aging

Replacing Sn-Pb solder with lead-free solder is a great challenge in the electronics industry. The presented lead-free solder is Sn based and forms two intermetallic species upon reaction with the Cu substrate, namely Cu6Sn5 and Cu3Sn. The growth of Cu6Sn5 and Cu3Sn intermetallics have been investigated with respect to Sn-40Pb/Cu solder joints. The joints were aged under long-term thermal exposure using single shear lap joints and the intermetallics were observed using scanning electron microscopy. As-soldered solder joints exhibit a single Cu6Sn5 phase, however after aging a Cu3Sn layer below the Cu6Sn5 is observed to manifest. The Cu6Sn5 layer develops with a scalloped morphology, whereas the Cu in layer always develops an undulating planar shape in phase with the Cu6Sn5. The Cu6Sn5 layer begins to transform from a scalloped- to a planar-shape as aging progresses in order to minimize the interfacial energy. The intermetallic layers exhibit a linear dependence on the square root of aging time, which corresponds to diffusion-controlled growth. The activation energy for the growth of the Cu6Sn5 intermetallic layer has been determined to be 56.16 kJ/mol.

Cu6Sn5 and Cu3Sn Intermetallics Study in the Sn-40Pb/Cu System during Long-term Aging

Replacing Sn-Pb solder with lead-free solder is a great challenge in the electronics industry. The presented lead-free solder is Sn based and forms two intermetallic species upon reaction with the Cu substrate, namely Cu6Sn5 and Cu3Sn. The growth of Cu6Sn5 and Cu3Sn intermetallics have been investigated with respect to Sn-40Pb/Cu solderjoints. The joints were aged under long-term thermal exposure using single shear lap joints and the intermetallics were observed using scanning electron microscopy. As-soldered solder joints exhibit a single Cu6Sn5 phase, however after aging a Cu3Sn layer below the Cu6Sn5 is observed to manifest. The Cu6Sn5 layer develops with a scalloped morphology, whereas the Cu3Sn layer always develops an undulating planar shape in phase with the Cu6Sn5. The Cu6Sn5 layer begins to transform from a scalloped- to a planar-shape as aging progresses in order to minimize the interfacial energy. The intermetallic layers exhibit a linear dependence on the square root ofaging time, which corresponds to diffusion-controlled growth. The activation energy for the growth of the Cu6Sn5, intermetallic layer has been determined to be 56.16 kJ/mol.

Flux emergence and coronal eruption

Our aim is to study the photospheric flux distribution of a twisted flux tube that emerges from the solar interior. We also report on the eruption of a new flux rope when the emerging tube rises into a pre-existing magnetic field in the corona. To study the evolution, we use 3D numerical simulations by solving the time-dependent and resistive MHD equations. We qualitatively compare our numerical results with MDI magnetograms of emerging flux at the solar surface. We find that the photospheric magnetic flux distribution consists of two regions of opposite polarities and elongated magnetic tails on the two sides of the polarity inversion line (PIL), depending on the azimuthal nature of the emerging field lines and the initial field strength of the rising tube. Their shape is progressively deformed due to plasma motions towards the PIL. Our results are in qualitative agreement with observational studies of magnetic flux emergence in active regions (ARs). Moreover, if the initial twist of the emerging tube is small, the photospheric magnetic field develops an undulating shape and does not possess tails. In all cases, we find that a new flux rope is formed above the original axis of the emerging tube that may erupt into the corona, depending on the strength of the ambient field.

Meiobenthic trace fossils comprising a miniature ichnofabric from Late Permian carbonates of the Oman Mountains

An ichnofabric composed of meiobenthic trace fossils is described from Late Permian shelf carbonates of the Arabian Platform from the Oman Mountains (Saiq Formation, Akhdar Group). It mainly consists of an 8–10 cm deep boxwork with an undulating burrow outline, with an average burrow diameter of about 0.5 mm. The pinch-and-swell-like features lead to bulbous enlargements and alternating blade-like contractions and are diagnostic for Virgaichnus undulatus igen. et isp. nov. In the upper tier of the ichnofabric, V. undulatus is associated with miniature spreiten-like lobes, which originate from a vertical shaft. These circular, elliptical or elongated lobes in the centimetre-range consist of irregularly arranged probes less than 1 mm in diameter and are assigned to Hydrancylus isp. The assessment of burrowing mechanism, burrow complexity, burrow size and geological age indicates worm-like organisms as potential trace makers for V. undulatus. The undulating shape of the burrow segments is in agreement with a peristaltic movement of a non-segmented, highly deformable vermiform body as known from nemerteans. The presented case demonstrates that morphology in combination with size is invaluable for the interpretation of the trace maker and consequently strengthens the importance of meiobenthic trace fossils for palaeoenvironmental and facies analysis.

Measurement of joint roughness coefficient by using profilograph and roughness ruler

Joint roughness coefficient (JRC) is the key parameter for the empirical estimation of joint shear strength by using the JRC-JCS (joint wall compressive strength) model. Because JRC has such characteristics as nonuniformity, anisotropy, and unhomogeneity, directional statistical measurement of JRC is the precondition for ensuring the reliability of the empirical estimation method. However, the directional statistical measurement of JRC is time-consuming. In order to present an ideal measurement method of JRC, new profilographs and roughness rulers were developed according to the properties of rock joint undulating shape based on the review of measurement methods of JRC. Operation methods of the profilographs and roughness rulers were also introduced. A case study shows that the instruments and operation methods produce an effective means for the statistical measurement of JRC.

A Taxonomic Review of Phytolacca insularis (Phytolaccaceae)

The purpose of this study is to review the taxonomical position of Phytolacca insularis Nakai based on morphological characters and ITS sequences. Phytolacca insularis was similar to P. acinosa in the stem shape, inflorescence, apocarpous, eight pistils, eight stamens, pink anther, and eight fruits. But the unique difference between P. insularis and P. acinosa was leaf size and pistil color. Phytolaccri insularis and P. acinosa have a similar sculpturing patterns as an foveolate and microscabrate in pollen, but they differed from P. americana in having a bigger foveolae size in sculpture pattern. Phytolacca insularis and P. acinosa were similar in the seed size but different from P. americana by having a small size of seed. The seed surface of P. insularis and P. acinosa was similar with a irregularly undulate shape, but its feature of P. americana differed in having the reticulate shape. Phytolacc a insularis had identical ITS sequences with P. acinosa. Phytolacca insularis and P. acinosa have a close relationship in the morphological characters and ITS sequences. The examinations of morphology and ITS sequences suggest that P. insularis be a form of P. acinosa although it has been formerly treated as a distinct species.

Taxonomy, phylogeny, biogeography, and ecology of Sabulodinium undulatum (Dinophyceae), including an emended description of the species

SUMMARYSamples of Sabulodinium undulatum Saunders et Dodge, the type species of the monospecific genus, were collected and characterized from Germany, Russia, Japan and Canada. This species has a laterally flattened, oval cell with a truncated apex and a dorsally pointing small episome. The dorsal margin of the hyposome has an undulating shape. A dorsal spine and/or antapical spine are sometimes present. The specimens of this heterotrophic species are 27.5–42.5 μm long and 18.5–36.0 μm wide, and have a theca with the plate arrangement apical pore complex (APC) 5′ 1a 6″ 5c 4s 6′′′ 1′′′′. The shape of the dorsal theca is variable. The species distribution seems to be restricted to northern temperate regions. Sabulodinium undulatum occurred in all sandy eulittoral areas throughout the year and was also present in sandy sublittoral and supralittoral (beach) samples. The species can tolerate a broad range of temperatures and salinities. Sabulodinium occurred from −2.0 to +24.3°C and 4–35 salinity. It is likely that the observed variability in morphology and habitat reflect several varieties. We propose to establish three varieties within the species, namely S. undulatum var. undulatum, S. undulatum var. glabromarginatum, and S. undulatum var. monospinum. The systematic position of Sabulodinium is discussed in the context of comparative morphological and molecular phylogenetic data.

Heat Treatment Behavior of Tungsten Heavy Alloy

This paper focuses on the variations of static and dynamic properties of tungsten heavy alloy with heat treatment. The matrix phase of 93W-4.9Ni-2.1Fe (weight percent) has been penetrated into W/W grain boundaries during a cyclic heat treatment which consists of repeated isothermal holdings at 1150 °C and water quenching between them. By applying the cyclic heat treatment, the impact energy of tungsten heavy alloy is increased about three times from 57 to 170 J. When the tungsten heavy alloy is cyclically heat treated at 1150 °C and then re-sintered at 1485 °C, W/matrix interface is changed from round to undulated shape. The irregularity of the interface is increased with increasing the number of heat treatment cycles. From the measurement of the residual stress of W grains by X-ray diffraction, it is found that the irregularity of the interface is closely related with strain energy stemmed from the difference of thermal expansion coefficient between W particles and matrix phase. From dynamic ballistic test, it is found that the tungsten heavy alloy with undulated W grains forms many narrow fracture bands which are preferential for the self sharpening effect, thus, for the improvement of the penetration performance.

From Low-Dimensional Manganese(II) Azido Motifs to Higher-Dimensional Materials: Structure and Magnetic Properties

Four new inorganic-organic hybrid coordination polymers in which 1D or 2D manganese(II) azido inorganic motifs are interlinked into higher-dimensional networks have been synthesized by use of a series of bis(pyridyl)-type organic bridging ligands (linkers) with different side groups and/or different coordination orientations. The dimensionality and the topology of the manganese(II) azido motif and the whole structure are sensitive to the organic linkers used. Compounds 1 and 3 are 3D coordination polymers with pillared-layer architectures: in 1, 2D Mn(II) layers with alternate double end-on (EO) and single end-to-end (EE) azido bridges are pillared by zigzag organic linkers, and 3 is built from single EE azido-bridged Mn(II) layers and linear organic linkers. The 3D nets of 1, 3, and related compounds have been related to the specific length and coordination orientation of the organic pillars and the undulate shape of the manganese(II) azido layers. Consistent with their structures, both 1 and 3 exhibit weak ferromagnetism due to spin canting. Compound 1 is a weak ferromagnet with T(c) = 16 K, and 3 is a metamagnet with T(c) = 23 K. On the other hand, compounds 2 and 4 are 2D coordination networks in which 1D manganese(II) azido chains are interlinked by organic linkers: 2 is the first 2D network built from Mn(II) chains with alternate double EE and double EO azido bridges, which mediate antiferro- and ferromagnetic interactions, respectively; 4 is the first 2D network built from Mn(II) chains with only single EE azido bridges, which mediate antiferromagnetic interactions. The magnetic susceptibility of 4 exhibits a rapid rise at very low temperature, which may be attributed to paramagnetic impurities or spin canting.