Specific Shape Research Articles

Muscle-inspired soft robots based on bilateral dielectric elastomer actuators

Muscle groups perform their functions in the human body via bilateral muscle actuation, which brings bionic inspiration to artificial robot design. Building soft robotic systems with artificial muscles and multiple control dimensions could be an effective means to develop highly controllable soft robots. Here, we report a bilateral actuator with a bilateral deformation function similar to that of a muscle group that can be used for soft robots. To construct this bilateral actuator, a low-cost VHB 4910 dielectric elastomer was selected as the artificial muscle, and polymer films manufactured with specific shapes served as the actuator frame. By end-to-end connecting these bilateral actuators, a gear-shaped 3D soft robot with diverse motion capabilities could be developed, benefiting from adjustable actuation combinations. Lying on the ground with all feet on the ground, a crawling soft robot with dexterous movement along multiple directions was realized. Moreover, the directional steering was instantaneous and efficient. With two feet standing on the ground, it also acted as a rolling soft robot that can achieve bidirectional rolling motion and climbing motion on a 2° slope. Finally, inspired by the orbicularis oris muscle in the mouth, a mouthlike soft robot that could bite and grab objects 5.3 times of its body weight was demonstrated. The bidirectional function of a single actuator and the various combination modes among multiple actuators together allow the soft robots to exhibit diverse functionalities and flexibility, which provides a very valuable reference for the design of highly controllable soft robots.

Convolutional neural networks rarely learn shape for semantic segmentation

Shape learning, or the ability to leverage shape information, could be a desirable property of convolutional neural networks (CNNs) when target objects have specific shapes. While some research on the topic is emerging, there is no systematic study to conclusively determine whether and under what circumstances CNNs learn shape. Here, we present such a study in the context of segmentation networks where shapes are particularly important. We define shape and propose a new behavioral metric to measure the extent to which a CNN utilizes shape information. We then execute a set of experiments with synthetic and real-world data to progressively uncover under which circumstances CNNs learn shape and what can be done to encourage such behavior. We conclude that (i) CNNs do not learn shape in typical settings but rather rely on other features available to identify the objects of interest, (ii) CNNs can learn shape, but only if the shape is the only feature available to identify the object, (iii) sufficiently large receptive field size relative to the size of target objects is necessary for shape learning; (iv) a limited set of augmentations can encourage shape learning; (v) learning shape is indeed useful in the presence of out-of-distribution data.

Investigation of 3D printing of toddler foods with special shape and function based on fenugreek gum and flaxseed protein

The practicability of using corn and flaxseed protein as printing inks for manufacture of printed products specifically designed for toddlers as a dysphagia diet with high precision and special shapes with addition of fenugreek gum (FGG) was investigated. 3D printing was used to process grains and dysphagia-compatible food (corn) into a dietary product with attractive appearance which was also easy to swallow. Rheological measurements shown that appropriate amount of flaxseed protein (FP, 0–10 %) can reduce the stickiness and yield strength of printing material. Based on FTIR measurements, FP weakened the hydrogen bond strength of inks, but it was still an important gradient for the formation of the ink suitable for precision 3D printing. The TPA results shown that the addition of FP (0–10 %) remarkably reduced both the stickiness and hardness of the ink. These results shown that compared with the control group, materials with FGG additions possessed higher printing accuracy and self-supporting ability. Ink with 5 % FP content exhibited the best printability and swallowability, while ink with 10 % FP content had the lowest viscosity and hardness, but it was not suitable for 3D printing. 3D printing of objects printed using Ink-C (5%FP and 0.8 %FGG) showed high support characteristic and attractive appearance. According to the international IDDSI testing standards, Ink-C (5%FP and 0.8 %FGG), Ink-E (15%FP and 0.8 %FGG), and Ink-F (20%FP and 0.8 %FGG) were defined as level 5-minced and moist foods.

Rereading Guido’s Or voit tout en aventure

Or voit tout en aventure by Guido is often regarded as an archetype of the late-medieval notationally and rhythmically complex style that musicologists term the ars subtilior. Transmitted in Chantilly, Musée Condé, MS 564, the ballade has gained notoriety for both its self-reflexive text and its idiosyncratic notation. The song’s narrator laments the invention of new and confusing figures, but the song’s notation incorporates a collection of special note shapes—lozenge-shaped figures with appended stems and flags. Previous studies have emphasized the obscurity of the notation of Or voit. Three of its note shapes represent the same duration, leading scholars to suggest that the notation of the song is unnecessarily and thereby ironically complex and redundant. Analyzing Or voit from the psychological perspective of hypothetical performers as they think through the notation of the piece allows a new reading of the song to emerge. The notation of Or voit is not ambiguous but projects distinct gestures from which localized notational hierarchies can be inferred. The humor of Or voit can thus be located not in the notation but in the text, which claims dishonestly that the notation is “not well done.” Rereading Or voit from the performer’s psychological perspective illustrates that reflecting on the contrasting conceptual frameworks of historical notations can help to resolve music-analytical problems that, at face value, seem to arise from the playful incompetence of historical thinkers.

A Binocular Camera Calibration Method in Froth Flotation Based on Key Frame Sequences and Weighted Normalized Tilt Difference

3D froth information is a significant indicator of working condition recognition in froth flotation. To extract it accurately, the first and key step is camera calibration. Although there have been many camera calibration methods proposed in these years, they cannot handle well for binocular camera calibration in froth flotation. The main reason is that there is an open environment without support surface or special geometric shapes for camera calibration in froth flotation. Therefore, we propose a novel binocular camera calibration method based on key frame sequences and weighted normalized tilt difference. First, we extract a high-quality frame sequence by filtering out incomplete and out-of-focus images from the froth video. Then, we propose a method to measure the tilt degree of the planar plate and extract the key frame sequences of the planar plate based on the tilt difference. After that, we calculate the camera parameters by weighted normalized tilt difference under various poses. The proposed binocular camera calibration method uses the froth video to obtain accurate and robust camera parameters, and does not require auxiliary equipment. Experiments have demonstrated the effectiveness and flexibility of the proposed method in froth flotation.

Novel CMB constraints on the α parameter in alpha-attractor models

Cosmological α-attractors are a compelling class of inflationary models. They lead to universal predictions for large-scale observables, broadly independent from the functional form of the inflaton potential. In this work we derive improved analytical predictions for the large-scale observables, whose dependence on the duration of reheating and the parameter α is made explicit. We compare these with Planck and BICEP/Keck 2018 data in the framework of a Bayesian study, employing uniform logarithmic and linear priors for α. Our improved universal predictions allow direct constraints on the duration of reheating. Furthermore, while it is well-known that CMB constraints on the tensor-to-scalar ratio can be used to place an upper bound on the α parameter, we demonstrate that including the α-dependence of the scalar spectral tilt yields novel constraints on α. In particular, for small α, the scalar spectral tilt scales with log10 α, regardless of the specific potential shape. For decreasing α, this eventually puts the models in tension with CMB measurements, bounding the magnitude of α from below. Therefore, in addition to the upper bound from the tensor-to-scalar ratio, we derive the first lower bound on the magnitude of α for α-attractor T-models, log10 α = -4.2+5.4 -8.6 at 95% C.L.

Removal of Amphiphilic Polymer from Tertiary Oil Recovery Wastewater Using Insoluble Cyclodextrin Polymer

The wastewater produced by amphiphilic polymer flooding is seriously emulsified and difficult to treat. In recent years, insoluble β-cyclodextrin (β-CD) polymers were widely employed in removal and utilization of organics with specific sizes and shapes. In this paper, a new type of host β -CD insoluble polymer (HCDP) was synthesized using β -CD with tetrafluoro-phthalonitrile (TFPN) as the crosslinker. A kind of guest amphiphilic polymer (GAP) was synthesized and the inclusion performance of HCDP to GAP was studied by viscosity method. Besides, The inclusion complexes of HCDP and GAP was regenerated using washing method and the inclusion capacity of the regenerated CDP was tested for five cycles. The results showed that GAP’ s apparent viscosity increased dramatically at about 800 mg/L and it showed linear relationship (R-square was 0.99902) with polymer concentration below 400mg/L, so GAP’ s concentration can be checked by viscosity method. HCDP can rapidly adsorb GAP in aqueous solutions and reach the adsorption equilibrium in about 20 minutes in the process of inclusion, and the maximum equilibrium adsorption amount of HCDP to GAP was about 150 mg/g. HCDP showed a strong recycling capacity. After five cycles of regeneration, the adsorption capacity did not significantly reduced, and the adsorption capacity remained above 140 mg/g. All the results prove that the new type of β-CD insoluble polymer can be used to encapsulate amphiphilic polymers in EOR wastewater, the study provides a new way for the resource utilization of amphiphilic polymers in EOR wastewater.

Combustion synthesis and photoluminescence study of novel Sm3+ activated K3La(PO4)2 phosphor for n-UV solid state lighting

In the present study, a novel K3La(PO4)2:Sm3+ phosphor was prepared by the combustion method. The synthesized K3La(PO4)2:Sm3+ phosphor was characterized by XRD, SEM, PL (emission and excitation) and color chromaticity. The recorded X-ray diffraction pattern for the phosphor matches JCPDS no. 00–047–0468. From the SEM analysis, the phosphor had an average particle size of 2–25 micrometers and had a solid microcrystalline structure with specific uneven shapes and aggregation between the crystalline grains. The maximum excitation peak occurs at 403 nm, which corresponds to the 6H5/2→4F7/2 transition of the Sm3+ ions. From all the observed transitions, the emission band at 598 nm (6G5/2→6H7/2) shows an orange-red emission with prominent intensity. The emission intensity of the K3La(PO4)2:Sm3+ phosphor could reach a maximum of 1 mol % and then concentration quenching occurs. Further, concentration quenching is explained using Blasse’s equation and Dexter’s theory. The chromaticity findings of the synthesized phosphor had a CIE coordinate of (0.617, 0.381) and hence might be used for an orange-red emission in solid state lighting.

ABSOLUTE INVALIDITY IN TERMS OF THE COMPETITION AND CONSUMER PROTECTION ACT

While the sanction of invalidity in the classical view ‒ normalized by civil law and its application - does not raise any doubts, the way in which Article 6 section 2 of the Law on Competition and Consumer Protection is normalized has already provoked the doctrine to analyze this provision and its relation to the normalization contained in Article 58 of the Civil Code. Due to the specific shape of the regulation contained in the antitrust legislation, two competing currents have developed in the science of law, whose views, based on different arguments, evaluate the sanction of invalidity in Article 6 section 2 of the u.o.k.k. either as a solution analogous to that of the Civil Code, or as a provision of a special nature. This article attempts to summarize the currents worked out in the doctrine, while undertaking a dogmatic and comparative legal analysis. Undoubtedly, Article 6 section 2 of the u.o.k.k. is a kind of breakthrough in the way of understanding the sanction of absolute invalidity known from civil law.

Design modifications and scale-up of a novel soxhlet apparatus: Optimization of batch extraction of a biofuel oil from Crotalaria juncea seeds

Till date, a soxhlet extractor is found to be the most versatile equipment for extracting oil from oil-bearing seeds. Use of a conventional soxhlet apparatus is limited by the long extraction time to complete a certain quantity of transfer of solute due to inefficient contact between the extractant and solute. A novel design of a modified soxhlet apparatus, including an additional packed column inserted within the soxhlet thimble, is proposed to overcome the limitations. It is evident from the study that cylindrical and annular packed columns (inserted within the thimble) perform better as compared to the elliptical ones. An annular packed bed ensures better oil yield in comparison to the cylindrical one due to enhancement of mass transfer by multiple factors. In order to commercialize the production of juncea seed oil, an effective modeling, based on a comprehensive dimensional analysis (following similarity criteria), is applied for a scale-up. Four key dimensionless groups, namely, soxhlet specific shape factor (Ss), Reynolds number (Res),Froudenumber(Frs) and Peclet number (Pes) are identified. Oil yield is represented by another dimensionless group, soxhlet specific Stanton number (Sts). A multiple-factor regression analysis, using Central Composite Design (CCD) based response surface methodology, is used to develop some rational correlations of various combinations of the dimensionless groups. Necessary and sufficient understanding of the effects of the dimensionless groups [Ss, Res,Frs, and Pes] on the oil yield is important to choose proper scale-up criteria. A novel dimensionless number, the soxhlet number, S, is evolved. S determines the soxhlet performance in terms of oil yield. Maximization of S gives forms a basis of scale-up. This specific approach of scaling-up a soxhlet apparatus can be utilized in commercializing the production of juncea oil.

Detection, Localisation and Quantification of Structural Damage Using Changes in Modal Characteristics

The article defines and explains methods for detecting and locating damage and quantifying its extent on an example of a finite element model of a simple beam. The defined methods are based on a comparison of the decreases in the bending natural frequencies of the nominally damaged models against the intact model. This comparison assigns natural frequency decreases to curvature of a specific mode shape, which allows creation of an analytical reference model using polynomial regression, which assigns relative natural frequency decreases to the position on the beam. The localisation method assumes that the vector of the relative natural frequency decrease ratios are unique for each position on the beam. The quantification method considers as a relevant comparative quantity, slopes of relative natural frequency decreases, as a function of damage extent. Examples of damage localisation and quantification are defined, and the relative errors of these methods are analysed.

Form and contour: breeding and genetics of organ shape from wild relatives to modern vegetable crops.

Shape is a primary determinant of consumer preference for many horticultural crops and it is also associated with many aspects of marketing, harvest mechanics, and postharvest handling. Perceptions of quality and preference often map to specific shapes of fruits, tubers, leaves, flowers, roots, and other plant organs. As a result, humans have greatly expanded the palette of shapes available for horticultural crops, in many cases creating a series of market classes where particular shapes predominate. Crop wild relatives possess organs shaped by natural selection, while domesticated species possess organs shaped by human desires. Selection for visually-pleasing shapes in vegetable crops resulted from a number of opportunistic factors, including modification of supernumerary cambia, allelic variation at loci that control fundamental processes such as cell division, cell elongation, transposon-mediated variation, and partitioning of photosynthate. Genes that control cell division patterning may be universal shape regulators in horticultural crops, influencing the form of fruits, tubers, and grains in disparate species. Crop wild relatives are often considered less relevant for modern breeding efforts when it comes to characteristics such as shape, however this view may be unnecessarily limiting. Useful allelic variation in wild species may not have been examined or exploited with respect to shape modifications, and newly emergent information on key genes and proteins may provide additional opportunities to regulate the form and contour of vegetable crops.

Experimental investigation on the effect of process variables for the quality characteristics of AA 2024 processed in cold extrusion

Extrusion process has many applications in manufacturing industries due to its ability to produce products of high quality. Extrusion process can be classified into hot extrusion and cold extrusion. The cold forward extrusion is carried out at ambient temperature and has the additional benefit of improved mechanical characteristics. The metarial is compressed under intense pressure through a die orifice with a specific shape during the extrusion process. This process is effected by a few process variables, including die angle, punch speed, and lubrication are in greater extent towards the extrusion force requirement, microstructure and the product quality. Hence, the present experimental work focuses on extrusion of circular billet to produce cylindrical rod. Studying the behaviour of the material and the importance of the input process parameters during the cold extrusion process is the primary goal of this work. The experiments are carried out with AA 2024 alloy because of its wide applications in navy and aircraft structures. The varying die angles (10°, 20° & 30°) as well as punch speed (1.6 mm/min, 3.2 mm/min and 4.8 mm/min) and lubricants (molybdium sulphide (MoS2), zinc stearate and grease) chosen as input parameters. The out put responses of this extrusion process are extrusion force, displacement, time and surface roughness. Extrusion forces are calculated based on flow stress curves at the locations of greatest elastic deformation. The results shows that increasing the punch speed and die angle increases the extrusion force. The microstructure evolutions and grain refinement at different die angles are examined using electron back scatter diffraction analysis. At 30° die angle, the microstructure showed grain refinement. It is also noted that the damage is significant at 30° die angle with a punch speed above 4.8 mm/min.

Claw shape variation in oribatid mites of the genera Carabodes and Caleremaeus: exploring the interplay of habitat, ecology and phylogenetics.

Claws are a commonly observed biological adaptation across a wide range of animal groups. They serve different functions and their link to evolution is challenging to analyze. While there are many studies on the comparative anatomy and morphology of claws in reptiles, birds and several arthropods, knowledge about claws of soil-living oribatid mites, is still limited. Recent research on intertidal oribatid mites has shown that claw shape is strongly correlated with microhabitat and is subject to ecological selective pressures. However, the selective constraints shaping claws in terrestrial oribatid mites are still unknown. In this study, 300 specimens from 12 different species and two genera were examined. Geometric morphometrics were used to quantify claw length and curvature, and to analyze two-dimensional claw shape. In combination with molecular phylogenetic analyses of investigated populations phylogenetic signal was quantified within genera using Blomberg's K and random replicates. Additionally, ecological information on the investigated species was gathered from previous studies and compiled into tables. The claw shapes of Carabodes species vary moderately, with the three species C. reticulatus, C. rugosior and C. tenuis deviating the most from the others. These three species are only found in a small number of habitats, which may require a more specialized claw shape. Our results show that there is a phylogenetic influence on claw shape in Carabodes but not in Caleremaeus. Additionally, habitat specificity and lifestyle were found to have ecological impact on claw shape in both genera. The present results demonstrate that characteristics of the claws of terrestrial oribatid mites are correlated with ecology, but this correlation is apparently weaker than in intertidal oribatid mites that are prone to strong external forces.

Advances in Phytonanotechnology: A Plant-Mediated Green Synthesis of Metal Nanoparticles Using Phyllanthus Plant Extracts and Their Antimicrobial and Anticancer Applications.

Nanoparticles and nanotechnology developments continue to advance the livelihood of humankind. However, health challenges due to microorganisms and cancerous cells continue to threaten many people's lives globally. Therefore, new technological interventions are of great importance. The phytochemicals present in medicinal plants are suggested as biocompatible, cost-effective, and regenerative sources that can be utilized for the green synthesis of nanoparticles. Different plant extracts with various phytochemical constituents can form nanoparticles with specific shapes, sizes, and optical properties. This review focuses on advances in green nanotechnology and provides details on reliable synthetic routes toward medically and biocompatible relevant metallic nanoparticles. We cover a wide range of applications that use phytonanoparticles with an in-depth look at what makes these materials interesting. The study also provides details of the literature on the interventions made in phytonanotechnology for the production of plant-mediated synthesis and capped metallic nanoparticles and their applications in various industries. It was observed that a variety of plants have been well studied, and detailed findings have been reported; however, the study of Phyllanthus is still in its early stages, and more needs to be uncovered.

Data-Driven Diagnosis of Multicopter Thrust Fault Using Supervised Learning with Inertial Sensors

This study proposes a data-driven fault diagnosis for multicopter unmanned aerial vehicles that uses the principal direction vector of inertial measurement unit (IMU) sensor signals calculated by principal component analysis. The main idea comes from the fact that a normal sphere-shaped distribution of the sensor data changes to a specific elliptical shape under a certain thrust fault situation. The fault diagnosis is based on classification and regression using supervised learning with the gyroscope and accelerometer datasets of an IMU. We analyze the performance of the proposed approach by depending on different learning algorithms. To verify the diagnostic performance, ground experiments with a hexacopter on the gimbaled jig are performed for various cases of damaged propellers. Then, the applicability of the proposed data-driven fault diagnosis is confirmed by analyzing the accuracy of the fault’s location and degree.

Multi-Layer TiO2−x-PEDOT-Decorated Industrial Fe2O3 Composites as Anode Materials for Cycle-Performance-Enhanced Lithium-Ion Batteries

An industrial submicron-sized Fe2O3 with no special shape was decorated by a multi-layer coating of oxygen-deficient TiO2−x and conducting polymer PEDOT (poly 3,4-ethylenedioxythiophene). A facile sol–gel method followed by an EDOT polymerization process was adopted to synthesize the hierarchical coating composite. The microstructure and phase composition were characterized using an X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). In particular, the existence state of PEDOT was determined using Fourier transform infrared (FT-IR) and a thermogravimetric (TG) analysis. The characterization results indicated the dual phase was well-coated on the Fe2O3 and its thickness was nano scale. Electrochemical characterization indicated that the multi-layer coating was helpful for significantly enhancing the cycle stability of the Fe2O3, and its electrochemical performance was even better than that of the single-layer coating samples. The synergistic effects of the ceramic phase and conducting polymer were demonstrated to be useful for improving electrochemical properties. The obtained FTP-24 sample exhibited a specific discharge capacity of 588.9 mAh/g after 360 cycles at a current density of 100 mA/g, which effectively improved the intrinsic cycling performance of the Fe2O3, with a corresponding discharge capacity of 50 mAh/g after 30 cycles.

Testing the optimality of USDA's WASDE forecasts under unknown loss

AbstractMotivated by the long‐lasting debate on whether the United States Department of Agriculture's (USDA's) World Agricultural Supply and Demand Estimates (WASDE) forecasts are optimal, we employ an unknown loss method for ex post evaluation which assumes that the USDA forecasters' loss function is unknown. We conduct optimality tests of the WASDE forecasts for corn, soybeans, and wheat published during 1988–2019. Our results suggest that USDA forecasters generally realize optimality during the data‐generating process. Our findings are consistent with previous studies when narrowing down the more general unknown loss function to the symmetric or asymmetric loss function which assumes a specific shape for the loss function. This study provides implications based on the unknown loss function that the USDA forecasters can boost their information set as an alternative way to improve the WASDE forecasts. [EconLit Citations: D84, E37, Q13, Q14].

Multi-state, three-way, normally open mini valve based on 3D printed flexible magnets using origami-inspired magnetization

Electromagnetic mini valves for controlling pneumatic soft actuators are attracting widespread interest in recent years. However, it is known that the traditional electromagnetic valves on the millimeter scale generally have three or fewer working states, and their moving parts are usually permanent magnets with a special shape that needs expensive manufacturing. To overcome these problems, this study aims to develop a mini valve with four working states based on flexible magnets at a low fabrication cost. We take full advantage of low-cost 3D-printed magnets’ physical and magnetic properties and improve their performance through origami-inspired magnetization. A fixed-beam-structure flexible magnet is proposed to control this valve via deformation so that valve’s two sides can be driven independently, resulting in four working states. Compared with conventional sintered magnets, 3D printing magnets can be manufactured quickly and affordably. Due to the proposed valves’ more operating states than the state-of-art three-way ones, they are proven to reduce the number of small control elements in the pneumatic system. The maximum flow rate of the valve at 5 kPa air pressure was 0.81 l min−1 at the power consumption of 20 W. This mini valve has the potential in controlling multi-degree-of-freedom pneumatic soft actuators.

Real-Time Hand Gesture Recognition Using YOLO and (Darknet-19) Convolution Neural Networks

There are at least three hundred and fifty million people in the world that cannot hear or speak. These are what are called deaf and dumb. Often this segment of society is partially isolated from the rest of society due to the difficulty of dealing, communicating and understanding between this segment and the rest of the healthy society. As a result of this problem, a number of solutions have been proposed that attempt to bridge this gap between this segment and the rest of society. The main reason for this is to simplify the understanding of sign language. The basic idea is building program to recognize the hand movement of the interlocutor and convert it from images to symbols or letters found in the dictionary of the deaf and dumb. This process itself follows mainly the applications of artificial intelligence, where it is important to distinguish, identify, and extract the palm of the hand from the regular images received by the camera device, and then convert this image of the movement of the paws or hands into understandable symbols. In this paper, the method of image processing and artificial intelligence, represented by the use of artificial neural networks after synthesizing the problem under research was used. Scanning the image to determine the areas of the right and left palm. Non-traditional methods that use artificial intelligence like Convolutional Neural Networks are used to fulfill this part. YOLO V-2 specifically was used in the current research with excellent results. Part Two: Building a pictorial dictionary of the letters used in teaching the deaf and dumb, after generating the image database for the dictionary, neural network Dark NET-19 were used to identify (classification) the images of characters extracted from the first part of the program. The results obtained from the research show that the use of neural networks, especially convolution neural networks, is very suitable in terms of accuracy, speed of performance, and generality in processing the previously unused input data. Many of the limitations associated with using such a program without specifying specific shapes (general shape) and templates, hand shape, hand speed, hand color and other physical expressions and without using any other physical aids were overcome through the optimal use of artificial convolution neural networks.