Search Results (11)

Various types of sensilla are densely distributed on the antennal surfaces of insects. The specialization of perception and ecological adaptability of antennae in detecting external environmental signals are reflected in the morphology, function, number, and distribution pattern of sensilla. L. invasa, O. bipolaris, and O. maskelli are three types of wasps that harm eucalyptus trees. To investigate the perception and reception methods of chemical signals from eucalyptus trees by the three gall wasps and compare interspecific differences, the antennal morphology and sensillar characteristics of these three gall wasps were systematically analyzed using scanning electron microscopy, including sensillar length, type, distribution, and number. Knee-shaped antennae, comprising the radicle, scape, pedicel, anelli, funicle, and club, are present in all three species. However, significant interspecific differences were observed in total antennal length and funicular number. Five major sensilla categories, comprising nine subtypes, were identified. Among these, five types (BS, CH, CS, TSI, TSII) were common to all three gall wasp species. PSI and PSII were unique to L. invasa, while O. bipolaris and O. maskell shared PSIII. Compared to O. maskelli, O. bipolaris possessed a significantly greater number of PSIII sensilla, which were also longer. TSIII was found exclusively in O. bipolaris. Interspecific differences were evident in antennal morphology, as well as in the number, size, and distribution of the sensilla. These variations in sensilla and antennal shape serve as a morphological foundation for species identification in addition to reflecting ecological adaptation and functional differentiation in environmental signal perception. Full article

Gridshell structures are characterized by an impressive strength-to-weight ratio, allowing their application in large-span roofing structures. However, their complex construction process and maintenance limited their widespread application. In recent years, the development of parametric and computational design tools has rekindled interest in this type of structure. Among these techniques, the Multibody Rope Approach (MRA) is a form-finding method based on the dynamic equilibrium of a system of masses (nodes) connected by ropes, which allows optimizing the structural shape starting from the dual geometry of the funicular network. To optimize the construction process, an improved version of the MRA, i-MRA, has been recently developed by the authors with the goal of uniforming the size of the structural components. To investigate the impact of the i-MRA method on the structural behavior of gridshell structures, the practical case of the design of a mosque roof is here analyzed. The comparison is carried out in terms of structural performance with respect to permanent and equivalent quasi-static loads. In addition, free-vibration natural-frequency shift is obtained by performing linear modal analysis. Finally, the global behavior with respect to buckling and elastic instability is assessed solving the relevant eigenvalue problem. The results demonstrate that for the roofing of the Dakar mosque, the structural configuration obtained through i-MRA is superior in terms of both construction efficiency and structural performance. The achieved shape exhibits a more uniform distribution of stresses induced by the applied loads together with very limited structural element typologies. Full article

Understanding the critical stages in ovule development is essential for optimizing in vitro seed propagation, cryopreservation, and indirect somatic plant embryogenesis. We studied the main stages of the megasporogenesis and megagametogenesis of Coelogyne speciosa subsp. fimbriata (J.J.Sm.) Gravendeel by confocal laser scanning microscopy. The ovule is anatropic, tenuinucellate, bitegmal, and funicular. The embryo sac is monosporic, Polygonum-type, bipolar, and usually 8-nuclear, but in cases of a reduction in the last mitotic division, it is 6-nuclear. Endosperm formation was not detected. The formation of a functional megaspore occurred 65–70 days after pollination (DAP), while the formation of a mature embryo sac and fertilization occurred after 85–100 DAP. Full article

Architects throughout the ages have looked to nature for answers to complex questions about the most appropriate structural forms for their buildings. This is the case of Jørn Utzon and the design of roof shells of the Sydney Opera House, in which the search for natural references was constant, from the nautical references in the initial design phases to the final spherical solution based on the analogy with an orange. This paper analyzes the influence of nature as a source of inspiration in this World Heritage building, assessing through FEM calculation models the suitability of the different solutions proposed and weighing up the influence of certain factors such as scale in this type of process. Through the calculation models developed, it has been possible to verify the poor performance of the initial designs compared to the power of the final solution, which, after more than 5 years of research by the design team headed by Utzon, was able to solve the enormous problem with a “simple” typological and geometric change. Full article

Orchiectomy is a common surgical procedure performed on small animals, and it requires postoperative pain management despite its relative simplicity. This study aimed to evaluate the hemodynamic stability, intraoperative administration of additional hypnotic and/or analgesic drugs, and postoperative pain scores following the combination of ultrasound-guided injection of ropivacaine hydrochloride into the spermatic cord and infiltration by the same anaesthetic of the incisional prescrotal line (ROP) or general anaesthesia. Dogs in the ROP group showed greater intraoperative hemodynamic stability and lower pain scores than the control group. The locoregional approach used in this study proved effective in minimising the responses to the surgical stimulus and ensured adequate analgesia intra- and postoperatively. This method, called ultrasound-guided funicular block, allows orchiectomy to be performed under deep sedation without general anaesthesia. Full article

A uniform theory of diffraction (UTD)-based method for analysis of the multiple diffraction of acoustic waves when considering a series of symmetric obstacles with arbitrary modeling, height and spacing is hereby presented. The method, which makes use of graph theory, funicular polygons and Fresnel ellipsoids, proposes a novel approach by which only the relevant obstacles and paths of the scenario under study are considered, therefore simultaneously providing fast and accurate prediction of sound attenuation. The obstacles can be modeled either as knife edges, wedges, wide barriers or cylinders, with some other polygonal diffracting elements, such as doubly inclined, T- or Y-shaped barriers, also considered. In view of the obtained results, this method shows good agreement with previously published formulations and measurements whilst offering better computational efficiency, thus allowing for the consideration of a large number of obstacles. Full article

In the proposed paper, non-equilibrium and equilibrium models of heat and moisture transfer through wet building materials are presented and compared. In the former, the mass transfer between liquid and gaseous moisture results from the difference between the partial pressure of water vapor and its saturation value. In the second model, the equilibrium between both phases is assumed. In the non-equilibrium model, liquid moisture can be in the continuous (funicular) or discontinuous (pendular) form. The transfer of moisture for each proposed model is tightly coupled with the energy transfer, which is assumed to be an equilibrium process. The time step and grid size sensitivity analysis of both numerical models are performed primarily. The verification of the model is based also on the numerical data available in literature. Finally, obtained with considered models, temporal variations of moisture content in three locations in the computational domain are compared. Reasonable conformity of results is reported, and discrepancies related to differences in formulations of models are discussed. Full article

In a “classical” vertical planar arch bridge subjected only to in-plane loads, its funicular geometry (which is the geometry that results in an equilibrium state free from bending stresses, i.e., simply under axial forces) is contained within a vertical plane. In the so-called “spatial arch bridges,” their structural behavior extends from the essentially vertical in-plane behavior of the “classical” arch bridges to a three-dimensional behavior. The paper presents how the Force Density Method, which is a form-finding method originally developed for cable meshes, can be simplified to easily obtain three-dimensional funicular arches. The formulation and flow chart of the method is presented and discussed in detail within this paper. Additionally, some case studies illustrate its scope. This paper intends to be useful at the conceptual stage of bridge design when the three-dimensional geometry for the spatial arch bridge typology is considered either because of functional requirements, structural efficiency, or for aesthetical purposes. Full article

We discuss the different challenges, pros and cons of the fairly new Structure for Motion (SfM) embarked on a vehicle (SfM-EV) technique for slope surveys along transportation network tracks using action cameras embarked on standard moving vehicles. This low-cost technique generates georeferenced and coloured 3D point clouds without using any ground control points. Four action cameras, two of which had an integrated GNSS chip, were used to collect a series of pictures of tracksides at a rate of two images per second each. The SfM-EV results were compared with the results of seven other 3D survey techniques to evaluate the precision and accuracy of this technique, demonstrating the ability of this simple setting to generate 3D scenes. Different platforms for the cameras were tested, such as a bike, car, train, funicular, helicopter and so on. The SfM-EV technique was also tested on several study sites to highlight its strengths and weaknesses and obtain data, such as the density of points, equations of errors, overlap ratios and image resolution. The precision of the SfM-EV results was sufficient for detecting topographical changes close to the track for a volume of ~1 dm³ and the absolute positioning obtained with a low sky obstruction was approximately 5 m. The precision of SfM-EV was of a similar order to the other techniques, with an order of magnitude of a few centimetres. This approach possesses a low price-result quality ratio and is very simple to use. The possibility of using any type of vehicle for surveying is an advantage, especially for transportation track embankments. Full article

The static problem for elastic shallow cables suspended at points at different levels under general vertical loads is addressed. The cases of both suspended and taut cables are considered. The funicular equation and the compatibility condition, well known in literature, are here shortly re-derived, and the commonly accepted simplified hypotheses are recalled. Furthermore, with the aim of obtaining simple asymptotic expressions with a desired degree of accuracy, a perturbation method is designed, using the taut string solution as the generator system. The method is able to solve the static problem for any distributions of vertical loads and shows that the usual, simplified analysis is just the first step of the perturbation procedure proposed here. Full article

Steel ropes are complex flexible structures used in many technical applications, such as elevators, cable cars, and funicular cabs. Due to the specific design and critical safety requirements, diagnostics of ropes remains an important issue. Broken wire number in the steel ropes is limited by safety standards when they are used in the human lifting and carrying installations. There are some practical issues on loose wires—firstly, it shows end of lifetime of the entire rope, independently of wear, lubrication or wrong winding on the drums or through pulleys; and, secondly, it can stick in the tight pulley—support gaps and cause deterioration of rope structure up to birdcage formations. Normal rope operation should not generate broken wires, so increasing of their number shows a need for rope installation maintenance. This paper presents a methodology of steel rope diagnostics and the results of analysis using multi-criteria analysis methods. The experimental part of the research was performed using an original test bench to detect broken wires on the rope surface by its vibrations. Diagnostics was performed in the range of frequencies from 60 to 560 Hz with a pitch of 50 Hz. The obtained amplitudes of the broken rope wire vibrations, different from the entire rope surface vibration parameters, was the significant outcome. Later analysis of the obtained experimental results revealed the most significant values of the diagnostic parameters. The evaluation of the power of the diagnostics was implemented by using multi-criteria decision-making (MCDM) methods. Various decision-making methods are necessary due to unknown efficiencies with respect to the physical phenomena of the evaluated processes. The significance of the methods was evaluated using objective methods from the structure of the presented data. Some of these methods were proposed by authors of this paper. Implementation of MCDM in diagnostic data analysis and definition of the diagnostic parameters significance offers meaningful results. Full article