Shape Modification Research Articles

Evaluation of the Upper Arch Morphological Changes after Two Different Protocols of Expansion in Early Mixed Dentition: Rapid Maxillary Expansion and Invisalign® First System.

Background: The objective of this retrospective study was to analyze the morphological changes of the upper arch after two protocols of expansion, the Invisalign® First system and rapid maxillary expansion (RME), in mixed dentition by means of geometric morphometric analysis (GMM). Methods: Digital dental casts of 32 children treated either with RME (RME group: 17 subjects; mean age 8.1 years) or the First system (First group: subjects; mean age 8.4 years) were collected. For both the RG and FG, pre-(T1) and post-treatment(T2) digital models were created. A total of 14 landmarks were digitized and GMM was applied. Procrustes analysis and principal component analysis (PCA) were performed. Results: The PC1 resulting from the T2–T1 comparison in the RG g showed statistically significant morphological changes in the posterior region of the upper arch shape, without significant variations in the anterior region. The comparison of the T2–T1 changes in the FG showed an increase in the transverse dimension at the level of the canine and the first deciduous molar widths, with morphological variation in the anterior region due to frontal teeth alignment. Conclusions: The First system induced shape modifications of the upper arch during expansion in contrast to RME. The FG presented an improvement in the maxillary arch shape, while the RG maintained the initial triangular shape.

Protection of gait data set for preserving its privacy in deep learning pipeline

Human gait is a biometric that is being used in security systems because it is unique for each individual and helps recognise one from a distance without any intervention. To develop such a system, one needs a comprehensive data set specific to the application. If this data set somehow falls in the hands of rogue elements, they can easily access the secured system developed based on the data set. Thus, the protection of the gait data set becomes essential. It has been learnt that systems using deep learning are easily prone to hacking. Hence, maintaining the privacy of gait data sets in the deep learning pipeline becomes more difficult due to adversarial attacks or unauthorised access to the data set. One of the popular techniques for stopping access to the data set is using anonymisation. A reversible gait anonymisation pipeline that modifies gait geometry by morphing the images, that is, texture modifications, is proposed. Such modified data prevent hackers from making use of the data set for adversarial attacks. Nine layers were proposedto effect geometrical modifications, and a fixed gait texture template is used for morphing. Both these modify the gait data set so that any authentic person cannot be identified while maintaining the naturalness of the gait. The proposed method is evaluated using the similarity index as well as the recognition rate. The impact of various geometrical and texture modifications on silhouettes have been investigated to identify the modifications. The crowdsourcing and machine learning experiments were performed on the silhouette for this purpose. The obtained results in both types of experiments showed that texture modification has a stronger impact on the level of privacy protection than geometry shape modifications. In these experiments, the similarity index achieved is above 99%. These findings open new research directions regarding the adversarial attacks and privacy protection related to gait recognition data sets.

Temperature stability of individual plasmonic Au and TiN nanodiscs

Refractory plasmonic materials are of interest for high-temperature plasmonic applications due to their increased thermal stability when compared to gold and silver. Titanium nitride (TiN) has been highlighted as a promising refractory material, offering both strong plasmonic and thermal performance. In this work, we analyze the stability of both the structural and optical response of individual plasmonic nanodiscs of various diameters subjected to elevated temperature conditions in air. Using cathodoluminescence spectroscopy, we trace the resonance spectra and shape modifications of the same single TiN and Au discs annealed at increasing temperatures up to 325 °C. TiN discs display greater morphological stability, but the optical properties of both materials deteriorate from 200 °C, although the mechanisms of degradation are different. The results are essential for optimizing nanostructured materials for high temperature nanophotonic applications.

Cell Architecture-Dependent Constraints: Critical Safeguards to Carcinogenesis.

Animal cells display great diversity in their shape. These morphological characteristics result from crosstalk between the plasma membrane and the force-generating capacities of the cytoskeleton macromolecules. Changes in cell shape are not merely byproducts of cell fate determinants, they also actively drive cell fate decisions, including proliferation and differentiation. Global and local changes in cell shape alter the transcriptional program by a multitude of mechanisms, including the regulation of physical links between the plasma membrane and the nuclear envelope and the mechanical modulation of cation channels and signalling molecules. It is therefore not surprising that anomalies in cell shape contribute to several diseases, including cancer. In this review, we discuss the possibility that the constraints imposed by cell shape determine the behaviour of normal and pro-tumour cells by organizing the whole interconnected regulatory network. In turn, cell behaviour might stabilize cells into discrete shapes. However, to progress towards a fully transformed phenotype and to acquire plasticity properties, pro-tumour cells might need to escape these cell shape restrictions. Thus, robust controls of the cell shape machinery may represent a critical safeguard against carcinogenesis.

Improvement of hydrodynamic performance of the disk-shaped autonomous underwater helicopter by local shape modification

The hydrodynamic performance and the way to reduce the drag and increase the motion stability for a newly developed hovering autonomous underwater vehicle, a disk-shaped AUH (autonomous underwater helicopter), are investigated by computational fluid dynamics as well as pool and water-channel validation experiments. The hydrodynamic property is improved through local modification at the rear part of the original hull geometry (HG1), which results in a fore-aft asymmetric geometry (HG3). From the numerical simulation, it is found that with proper extension and sharpening at the rear part, separation of the boundary layer is delayed and the secondary flow area is effectively suppressed, which results in a remarkable reduction of the hydrodynamic drag as well as the drag and side force fluctuation. For the basic AUH hull, the temporal average drag of HG3 (65.3 N) is 26.5% lower than that of HG1 (88.9 N) at u=2m/s. The HG3 geometry also shows good stability against disturbance by the aquatic cabin attached at the central bottom, as well as propellers imbedded in the hull in a realistic working condition compared to the original geometry.

Investigating the Antibacterial Properties of ZnO-NPs

The size range of several hundred nanometers to several of micrometers contains a lot of microorganisms. The aim of the current report was to study the antibacterial properties of ZnO-NPs through a theoretical review of the most important findings in previous studies. The study found the most important antibacterial properties of ZnO-NPs, including: Strong antibacterial results can be achieved by enhancing variables such as UV light, zinc oxide particle size, concentration, shape, and surface modification, which affect many different toxicological processes. One of the main properties of ZnO-NPs is the production of intracellular ROS formation, as well as the mechanical damage of the cell wall due to the release of Zn2+ ion and its attachment to the cell membrane.

Screen-printed capacitive pressure sensors with high sensitivity and accuracy on flexible substrates

Printable elastic conductors promise large-area stretchable sensor/actuator networks for healthcare, wearables and robotics, among other areas. Force pressure sensors are one of their most attractive applications, although their large-area integration has been limited by difficulties in their processability or bendability and their use by their insufficient sensitivity or stability. In this work, we present a flexible screen-printed capacitive pressure sensor, able to be modularly integrated in large-area systems thanks to the substrate flexibility, bending within itself capability and not only at its intersections, and cuttability, allowing a range of modifications in size and shape for complex structures. We built the sensors with a microstructured dielectric, whose hill radii were tuned (between 125 and 375 µm) until obtaining a measurement range of five orders of magnitude, with a logarithm sensitivity above 20% dB−1 at the maximum pressure peak of 750 kPa and of 80% kPa−1 at the lowest test value of 0.5 kPa. These results went along completely with the theoretical model that we also developed. Besides, while smaller pillars showed a significant hysteresis for decreasing pressures, we observed how large hills performed with a small hysteresis of down to 3%, way ahead of the published sensors to the best of our knowledge.

'biogeom': An R package for simulating and fitting natural shapes.

Many natural objects exhibit radial or axial symmetry in a single plane. However, a universal tool for simulating and fitting the shapes of such objects is lacking. Herein, we present an R package called 'biogeom' that simulates and fits many shapes found in nature. The package incorporates novel universal parametric equations that generate the profiles of bird eggs, flowers, linear and lanceolate leaves, seeds, starfish, and tree-rings, and three growth-rate equations that generate the profiles of ovate leaves and the ontogenetic growth curves of animals and plants. 'biogeom' includes several empirical datasets comprising the boundary coordinates of bird eggs, fruits, lanceolate and ovate leaves, tree rings, seeds, and sea stars. The package can also be applied to other kinds of natural shapes similar to those in the datasets. In addition, the package includes sigmoid curves derived from the three growth-rate equations, which can be used to model animal and plant growth trajectories and predict the times associated with maximum growth rate. 'biogeom' can quantify the intra- or interspecific similarity of natural outlines, and it provides quantitative information of shape and ontogenetic modification of shape with important ecological and evolutionary implications for the growth and form of the living world.

Impacts of zonal winds on planetary oscillations and Saturn ring seismology

ABSTRACT The excitation of density and bending waves in Saturn’s C ring by planetary oscillation modes presents a unique opportunity to learn about gas giant interiors and rotation. However, theoretical complications related to Saturn’s rapid and differential rotation pose a barrier to the full utilization of ring wave detections. We calculate oscillation modes using a complete, non-perturbative treatment of differential rotation modelled after Saturn’s zonal winds in self-consistently computed, polytropic equilibria. We find that previous, approximate treatments of the effects of differential rotation in Saturn overestimate shifts in the frequencies of fundamental modes (f modes) thought to be responsible for the majority of the waves detected in the C ring, due to an omitted modification of the equilibrium shape and structure of the planet by differential rotation. The bias introduced by these frequency overestimates is small, but significant relative to the uncertainties afforded by Cassini data. We additionally consider the non-perturbative effects of Saturn-like differential rotation on the rotational mixing of f modes and internal gravity modes (g modes), which is relevant to detections of multiple density waves with very closely split pattern speeds. We find that higher-order rotational effects can produce orders-of-magnitude enhancements in the surface gravitational perturbations of g modes dominated by large spherical harmonic degrees ℓ, regardless of frequency separation from the sectoral f mode. Despite this enhancement, we find that the observed fine splitting of density waves is unlikely to involve g modes dominated by ℓ ≳ 10. This restriction may aid in the inference of possible internal structures for Saturn.

Novel 3D Printing Encapsulation Strategies for Perovskite Photodetectors

AbstractThis work presents two different encapsulation strategies for perovskite photodetectors by testing the device stability under elevated ambient humidity of 85% and room temperature (25 °C). The single layer structure is adopted in the devices in order to accelerate the aging tests. The best stability (retention of ≈90% of initial photoresponsivity on average after 24 h, and ≈73% after 168 h) is obtained for devices protected by a flexible UV‐curable resin shell and encapsulated with AB epoxy including a desiccant sheet. The effects of the epoxy outgassing, the presence of desiccant, and the bending ability of encapsulated devices are also investigated. Additionally, with the assistance of 3D printing technology, a new possibility of research in the aspect of electrical device encapsulation is developed. Rapid iterative modifications in materials, shape, inner structure, and easy integration with outer component like desiccant ball/sheet make 3D printing assistance an ideal solution for the design of the encapsulation configuration and its early verification. This work not only opens up an optimal way for perovskite encapsulation by the 3D printing technology, but also provides an ideal solution for the design of the encapsulation configuration and its early verification.

Polymeric particle-based therapies for acute inflammatory diseases.

Acute inflammation is essential for initiating and coordinating the body’s response to injuries and infections. However, in acute inflammatory diseases, inflammation is not resolved but propagates further, which can ultimately lead to tissue damage such as in sepsis, acute respiratory distress syndrome and deep vein thrombosis. Currently, clinical protocols are limited to systemic steroidal treatments, fluids and antibiotics that focus on eradicating inflammation rather than modulating it. Strategies based on stem cell therapeutics and selective blocking of inflammatory molecules, despite showing great promise, still lack the scalability and specificity required to treat acute inflammation. By contrast, polymeric particle systems benefit from uniform manufacturing at large scales while preserving biocompatibility and versatility, thus providing an ideal platform for immune modulation. Here, we outline design aspects of polymeric particles including material, size, shape, deformability and surface modifications, providing a strategy for optimizing the targeting of acute inflammation.

Influence of fuel system variations on performance and emission characteristics of combined air-wall-guided mode modified GDI engine with alcoholic fuels and exhaust gas recirculation.

GDI engines commercially existed with spray-guided mode where the fuel injector placed almost vertically and sprayed fuel is occupied throughout the volume of combustion chamber. With the advanced emission norms, NOx and soot emissions control is the major task along with lower fuel consumption. To achieve the advanced emission norms, further modifications are required before or during combustion. Combined air-wall guided mode combustion chamber modification is the advanced stage required for further improvement in mixing and superior combustion. Combined air-wall guided mode involved piston crown shape modification so that the modified shape must impart turbulence effects and divert the fuel/mixture flow towards the spark plug tip to initiate the combustion process. In this study, the combined air-wall-guided mode gasoline direct injection engine was tested with gasoline blends using ethanol, methanol and N-butanol at 20, 35 and 50% proportions under specific fixed conditions: 1500rpm speed, 10% EGR and FIP of 150 bars with three split injections at 320°, 220° and 100° before TDC at different injection durations. Tests were conducted over these gasoline blend proportions for engine performance and emission characteristics and achieved the beneficial results with E20 gasoline blend over the entire applied torque values. E20 blend develops maximum IMEP of 8.3% at 50% blend proportion and as significant increment of 7.4% at 20% of blend proportion. E20 blended fuel shown a maximum decrement of SFC up to 7.2%. Significant reduction of CO emission up to 11.3% for E20 blend and maximum reduction of 12% for E50 blend. HC emissions were decreased significantly up to 14% for E20 blend and it reached maximum reduction of 20.3% for E50 blend. NOx emissions showed lower concentrations for E20 blend with a decrement of 13.3% and higher for B35 blend. Soot particle emissions were decreased significantly up to 27% for E20 blend and it reached maximum reduction of 33.34% for E50 blend.

Impact of Vertical and Horizontal Shape Modification on Tall Structure Subjected to Dynamic Wind Load: A Review

Abstract: In modern scenario rapidly increasing population resulted in scarcity of land. High-rise buildings are solution of this inevitable problem for providing accommodation to large amount of people in significantly less amount of land on affordable price. Skyscraper structures are more revered to twist powers at higher height focuses. At these points static analysis fails to give satisfactory results. To defeat these different nations incorporated the arrangement of Gust Effectiveness Method which considers the unique properties of construction, wind structure connection and afterward decides the breeze load as comparable to static burdens. In present work, research papers on dynamic behaviour of wind and Gust Effectiveness Method has been studied and conclusions are made. The effect of vertical and horizontal shape modification, plan ratio and aspect ratio with different terrain categories has also been studied.

Physical Modeling of Ice Cover Deformation Under the Action of a Moving Load at Low Speed

The current paper considers the possibility of physical modeling of ice cover deformation under the action of a moving load at low speed. Using an equation for elastic plate oscillations on the foundation of a hydraulic type, it is shown that similarity of a stress and strain state (SSS) of model ice can be achieved but within the scope of the approaches based on a classical theory of Nogid-Shimansky modeling of ice cover. Taking into account certain complications connected with practical implementation of the above method, the applicability of a reduced-thickness ice model developed at NNSTU is investigated. This model uses the ice thickness that intentionally does not comply with the similarity requirements, all other requirements being satisfied, thus providing incomplete similarity of the model. Some disagreements with a Nogid-Shimansky model connected with that are revealed and their influence on the end result is evaluated. The applicability of a thin ice model is investigated in natural cooled model tanks of classical shape used for modeling of load movement at low speed. The results of the experimental investigation of ice cover deformation under the action of a moving load using a model for the natural thin ice are given. The modification of a wave shape and maximum ice deflection depending on change of a movement speed and loading are investigated. The connection of decrease of a ratio of the deflection basin profile area to the outward ice bending profile in front of a moving load with increase of speed at the start of the movement is demonstrated, which can be an evidence of a sharp growth of energy expenses for ice cover deformation when the interaction between the technical facility and ice cannot be considered as quasistatic. An exact evaluation of such expenditures is crucial when designing the ice-breaking facilities clearing a path through floe ice.

Optical properties and complex refractive index of Co-doped ZnO waveguide thin films elaborated by spray pyrolysis

\({\text{Co}}_{x}{\text{Zn}}_{1-x}{\text{O}}\) (x = 0.00, 0.04, 0.08, and 0.10) thin films were sprayed pyrolysis onto ordinary glass substrates. The micro-Raman spectroscopy revealed the presence of wurtzite structure in all films. The UV–Vis investigation showed good optical transmittance in the visible region with the increase in the absorption bands related to internal \({\text{Co}}^{+2}\) d–d transitions over Co concentration. The optical gap energy decreased by 0.34 eV as Co doping increased, contrary to Urbach energy which increased by 230 meV. The SEM observation indicated grain shape modification of the surface morphology of the films in addition to slight decrease in the grain size. M-lines spectroscopy measured the ordinary refractive index which was found to increase by 0.0156 as the Co doping increased. Cobalt doping provoked the extinction of light coupling and propagation in the films manifested as an increase in full width at the half maximum of the guided peaks and a decrease in the reflected intensity. This was due to the increase in the extinction coefficient measured by UV–Vis spectroscopy.

Effect of the Nozzle Geometry on Flow Field and Heat Transfer in Annular Jet Impingement

The effects of nozzle shape modifications on the flow phenomena and heat transfer characteristics in annular jet impingement are investigated numerically. The numerical simulations are conducted applying the shear stress transport (SST) k−ω model in the ANSYS CFX. Two modified nozzles: the converging nozzle and the diverging nozzle, are investigated in this study, and the straight nozzle serves as the base case. The geometric parameters and settings are based on an annular jet ejected from an axial fan used for electronic cooling: the Reynolds number Re= 20,000 and the blockage ratio Br=0.35 in the computation, and the target plate is placed at three representative separation distances: H=0.5,2, and 4. Compared with the base nozzle, the converging nozzle can accelerate the cooling flow and promote turbulence to enhance local and overall heat transfer (about 20%) over the target surface. In addition, the converging nozzle reduces the sizes of the recirculation zones, and this promotes the convective heat transfer transport near the axis. The diverging nozzle experiences a similar flow pattern and thermal field as the base nozzle, while the diverging nozzle achieves a slightly lower heat transfer with a pronounced pressure drop reduction. In addition, given that the value of the Nusselt number over the target plate is dependent on the Reynolds number, the simulations are also performed at Re=5000 and 40,000 to establish the correlations between the Nusselt number and the Reynolds number as Nu∝Rem. The value of m varies depending on the nozzle shapes and the separation distances.

Variations in the carapace shape of whip spiders (Arachnida: Amblypygi).

Morphological studies often need to reference body size to correctly characterise the shape of organisms. In arthropods, the most commonly used reference for this is the length or width of the carapace, thorax, or the prosoma in the case of chelicerates. However, in the case of animals with unlimited growth, such as whip spiders, this measure could be irrelevant if growth is allometric. In this study, we analyse the ontogenetic modifications in prosoma outline shape in whip spiders during growth and compare the differences in shape between species. Differences are important for the relative prosoma width between species and, in the case of Damon medius, during growth in the juvenile stages, whereas the shape remains stable in mature stages. We conclude that a one-dimensional measure (i.e., length or width) suffices for mature specimens of a single species or family, but for larger studies, or when including immature specimens, at least the prosoma area (within the outline shape) should be used as a size estimator.

Mechanics of drag reduction of an axisymmetric body of revolution with shallow dimples

In this article, the mechanics of drag reduction on an axisymmetric body of revolution by shallow dimples is presented by using the high-fidelity Reynolds Stress Modeling based simulations. Experimental results of drag evolution from published literature at different Reynolds numbers are used to validate the model predictions. The numerical predictions show good agreement with the experimental results. It is observed that the drag of the body is reduced by a maximum of [Formula: see text] with such shape modification (for the depth to diameter ratio of [Formula: see text] and coverage ratio of [Formula: see text]). This arises due to the reduced level of turbulence, flow stabilization and suppression of flow separation in the boundary layer of the body. From the analysis of turbulence states in the anisotopic invariant map (AIM) for the case of the dimpled body, we show that the turbulence reaches an axisymmetric limit in the layers close to the surface of the body. There is also a reduced misalignment between the mean flow direction and principal axis of the Reynolds stress tensor, which results in such drag reduction. The dimple depth to diameter(s/d) and coverage ratio (a/A) are also varied to evaluate its effect on drag evolution. An empirical correlation for the drag coefficient is also developed by using polynomial regression in terms of the different shape and flow parameters, for example, s/d ratio, a/A ratio, and Reynolds shear stress.

Computational study on effect of enclosure shapes on melting characteristics of phase change material around a heated cylinder

This work investigates the melting and heat transfer characteristics from an isothermally heated circular cylinder placed inside twelve differentially shaped enclosures filled with the lauric acid (PCM). Extensive results are reported on streamlines, temperature contours, and rate of melting to delineate the influence of enclosure shape on the melting performance of thermal energy storage (TES) unit. The study is conducted at two different surface temperatures of the heated cylinder, namely, 333.15 K and 343.15 K. The time required to reach the fully melt condition largely depends on the amount of PCM above the heated cylinder and the interaction between the thermal boundary layers at the adiabatic wall and the cylinder surface. Among all shapes considered, the inverted semi-circular enclosure yields the fastest melting. Simple modifications in the geometrical shape of the enclosure are seen to significantly reduce the melting time (by ∼ four times) required to reach the fully melt condition thereby expediting the energy storage process. Thus, such elementary geometrical changes in the TES systems can hugely benefit by reducing the energy losses and yield larger industrial margins. At the end, limited results are also included for the complete melting-solidification cycle for the utilization of the results in a broader spectrum.

Effects of B Addition on the Microstructure and Microhardness of Melt-Spun Al-7075 Alloy

Abstract Main aim of this study is to examine change of microstructural and the mechanical properties of Al-7075 alloy depending on B content added with different proportions. Rapid solidification process used to produce the alloys was carried out with a single roll melt spinner via a wheel with a rotational speed of 25 m/s. For the microstructural characterization of the alloys, a scanning electron microscope and X-ray diffraction analyzes were used. According to obtained results, it can be said that B addition led to modification of dimensions and shapes of both α−Al and intermetallic phases occurred, it reduced average grain size from 0.45 μm to 0.34 μm in the microstructure. The B addition also led to dramatically increase in microhardness of the Al-7075 alloy. The microhardness of the alloy with 0.4 wt. % B is 0.19 GPa, this is clearly one times higher than that of the alloy without B addition. The microhardness of the alloy with 1 wt. % B is 0.21 GPa, this is also slightly higher than that of the alloy with 0.4 wt. % B.