Littérature scientifique sur le sujet « 3dbos »

The 3D body scanner (3DBS) is designed to capture three-dimensional human body shape information. With the growing interest in healthcare and the rapid development of technologies used in the 3DBS, various research has been conducted to apply 3DBS in different healthcare sectors. This study classified studies conducted outside South Korea on 3DBS from 2018 to 2023 based on their objectives and application fields. In addition, we investigated the standardization trends related to 3DBS by South Korean and worldwide standardization organizations to propose future research directions. 3DBS is utilized in various healthcare fields, such as Preventive health screening, monitoring, epidemiology, and diagnosis. Particularly in Preventive health screening, its application for body composition measurement has gained attention. However, due to the lack of international standards for body composition measurement using 3DBS, there have been discrepancies in research outcomes. Given the practical applications of 3DBS in healthcare and the ongoing evolution of international standards, there is a pressing need for standards specifically tailored to enhance the utility of 3DBS in the medical field.

Diante das mais variadas técnicas ortodônticas existentes na Ortodontia, a técnica 3DBOT (Tratamento Tridimensional Ortodôntico sem Bráquetes) se destaca por utilizar a tecnologia, o set up 3D, de forma obrigatória. Por definição, a técnica possibilita movimentos nas três dimensões do espaço, com alta previsibilidade dos movimentos, não necessitando dos bráquetes como suporte para a correção dentária. Os alinhadores asseguram o controle dos torques e um excelente detalhamento final. O presente estudo visa descrever um caso clínico de Classe I de Angle, com apinhamentos dentários, tratada com a técnica fixa 3DBOT e alinhadores. Os resultados foram alcançados na primeira etapa com duração de 8 meses, seguidos dos alinhadores finais por 3 meses. A técnica 3DBOT demonstrou ser uma opção eficaz, eficiente e principalmente confortável.

The 3DBOT technique (Three-Dimensional Orthodontic Treatment without Brackets) receives this name for performing movements in the 3 dimensions of the space without the use of brackets and with the help of technology through 3D set up. This technique includes advantages such as absolute control of protrusion / retrusion, control of the arch shape and the planned expansion, control of established vertical and anteroposterior movements. It is imperceptible and comfortable, in addition it is a straight and self-ligating technique that allows sliding when necessary. The objective of this work is to report a clinical case of Class II subdivision, using the 3DBOT technique with skeletal anchorage. The combination of the Versatile Skeletal Anchorage Plate on the palate and the 3DBOT technique proved to be a viable option for Class II malocclusion treatment.

Anterior open bite is a type of malocclusion in which there is the presence of a negative vertical overlap between the incisal edges of the upper and lower anterior teeth. It is considered a complex anomaly with distinct characteristics and difficult to treat with prevalence of 25% to 38% of patients orthodontically treated. The aim of this article is to report a clinical case of Class III right subdivision and open bite using 3DBOT technique, a fixed, comfortable, predictable, imperceptible technique with 3D technology and with extreme clinically proven satisfaction. Case report: Patient V.B.V.S., 23 years and 1 month old, leukoderma, male, mild dholico, straight profile, symmetrical, Class ¼ of Class III of molar and canine right subdivision, anterior open bite, inverted smile, mild upper and anterior dental crowding. Treatment plan: The use of 3DBOT was planned along with the use of intermaxillary elastics and refinement with the aid of MyAligner® aligners. Conclusion: The 3DBOT technique showed to be a viable option for treating anterior open bite

The Stewart Platforms (SP) bring relevant contributions to handling 3D environments. Among these contributions, the Ilizarov Hexapod Systems (IHS) are developed, aimed at correcting bone deformities. Thus, with the support of the Scrum framework, the development of a set of four 3D learning objects (3DLOs) was carried out, and was then evaluated by eight orthopedic doctors and eleven orthopedic residents. Finally, the contributions of the use of the software engineering Scrum framework in the construction of 3DLOs and its effectiveness as an instructional mechanism in IHS teaching-learning medicine were presented

Benefiting from the multi-directional load-bearing capability, the three-dimensional braided composites (3DBC) have found a wide application in primary structures. It is therefore of great importance to fully understand their mechanical behavior and failure modes. In the present paper, the tensile and compressive tests were carried out, according to standardized testing methods, for eight types of 3DBC, which were manufactured by resin transfer molding (RTM). It was found that the mechanical properties of the 3DBCs decreased with an increasing braiding angle. When the braiding angle was 20°, 3D 5-directional braided composite (3D5dBC) exhibited the best mechanical properties, while for the braiding angle of 40°, the mechanical properties of 3D6dBC were the most prominent. Moreover, the tensile strength of the 3DBCs is approximately two times as much as the compressive strength; however, the compressive modulus is always 10% higher than the tensile modulus. The failure modes of the 3DBCs with a braiding angle of 20°greatly depended on the braiding structures. However, they tend to be consistent when the braiding angle increases to 40°.

Mathematical model of sensitive structures and detection principle of Sigma-Delta accelerometer are analyzed in this paper, and then an accelerometer with SNR 107dB is designed using MATLAB, the stability of which is analyzed based on root locus plot. When input is small than-3dBFS, the system is unsaturated. The poles and zeros of accelerometer noise transfer function are then analyzed and the feed-forward coefficient and local feedback coefficient are optimized, achieving a higher SNR of 112.1dB. At last, the circuit-level simulation is conducted and in-band noise level is about-140dB.

The ever-increasing end user demands are instigating the development of innovative methods targeting not only data rate enhancement but additionally better service quality in each subsequent wireless communication standard. This quest to achieve higher data rates has compelled the next generation communication technologies to use multicarrier systems e.g. orthogonal frequency division multiplexing (OFDM), while also relying on the multiple-input multiple-output (MIMO) technology. This paper is focused on implementing a MIMO-OFDM system and on using various techniques to optimize it in terms of the bit-error rate performance. The test case considered is a system implementation constituting the enabling technologies for 4G and beyond communication systems. The bit-error rate optimizations considered are based on preceding the OFDM modulation step by Discrete Fourier Transform (DFT) while also considering various subcarrier mapping schemes. MATLAB-based simulation of a 2 ? 2 MIMO-OFDM system exhibits a maximum of 2 to 5 orders of magnitude reduction in bit-error rate due to DFT-precoding and subcarrier mapping respectively at high signal-to-noise ratio values in various environments. A 2-3dBs reduction in peak-to-average power ratio due to DFT-precoding in different environments is also exhibited in the various simulations.

Objective: The objective was to compare the shear bond strength (SBS) and the adhesive remnant index (ARI) amongst six orthodontic bracket groups. Materials and Methods: Three-dimensional printed polycrystalline alumina brackets (3DBs), ceramic brackets (CBs), and metal brackets (MBs), divided into six groups, were bonded to bovine incisors using different bonding procedures. The SBSs were obtained using a universal testing machine, and the ARIs were assessed with a stereomicroscope. The statistical analyses included one-way analysis of variance (ANOVA) for SBS differences and Fisher’s exact test to show ARI differences amongst the groups (p < 0.05). Results: No significant differences (p > 0.05) were measured amongst the SBSs of the 3DB groups (12.3 MPa, 12.6 MPa, 12.3 MPa, 11.0 MPa, respectively). The latter four groups generally had significantly lower SBSs (p < 0.001) than the conventional bracket groups, CB and MB (16.9 MPa and 19.3 MPa, respectively). Also, there was no significant difference in SBSs for the CB and MB groups (p > 0.05). A high ARI for CBs and MBs (2) indicated that more than 50% of the adhesive remained on the enamel surface. The four 3DB groups had no residual adhesive or less than 50% adhesive on the enamel surface after debonding (ARI scores 0 and 1). A significant difference in ARI levels existed across the types of brackets (p < 0.05). Conclusion: Three-dimensional printed polycrystalline alumina brackets exhibited adequate SBS values for successful bonding. However, the values were lower compared to those for conventional ceramic and metal brackets. The majority of the adhesive remnant for the 3D-printed brackets was mainly located on the bracket base.

AbstractPurposeTo develop a 3D, high‐sensitivity CEST mapping technique based on the 3D stack‐of‐spirals (SOS) gradient echo readout, the proposed approach was compared with conventional acquisition techniques and evaluated for its efficacy in concurrently mapping of guanidino (Guan) and amide CEST in human brain at 3 T, leveraging the polynomial Lorentzian line‐shape fitting (PLOF) method.MethodsSaturation time and recovery delay were optimized to achieve maximum CEST time efficiency. The 3DSOS method was compared with segmented 3D EPI (3DEPI), turbo spin echo, and gradient‐ and spin‐echo techniques. Image quality, temporal SNR (tSNR), and test–retest reliability were assessed. Maps of Guan and amide CEST derived from 3DSOS were demonstrated on a low‐grade glioma patient.ResultsThe optimized recovery delay/saturation time was determined to be 1.4/2 s for Guan and amide CEST. In addition to nearly doubling the slice number, the gradient echo techniques also outperformed spin echo sequences in tSNR: 3DEPI (193.8 ± 6.6), 3DSOS (173.9 ± 5.6), and GRASE (141.0 ± 2.7). 3DSOS, compared with 3DEPI, demonstrated comparable GuanCEST signal in gray matter (GM) (3DSOS: [2.14%–2.59%] vs. 3DEPI: [2.15%–2.61%]), and white matter (WM) (3DSOS: [1.49%–2.11%] vs. 3DEPI: [1.64%–2.09%]). 3DSOS also achieves significantly higher amideCEST in both GM (3DSOS: [2.29%–3.00%] vs. 3DEPI: [2.06%–2.92%]) and WM (3DSOS: [2.23%–2.66%] vs. 3DEPI: [1.95%–2.57%]). 3DSOS outperforms 3DEPI in terms of scan–rescan reliability (correlation coefficient: 3DSOS: 0.58–0.96 vs. 3DEPI: −0.02 to 0.75) and robustness to motion as well.ConclusionThe 3DSOS CEST technique shows promise for whole‐cerebrum CEST imaging, offering uniform contrast and robustness against motion artifacts.

L'objectif de cette thèse est d'étudier les mécanismes physiques qui gouvernent l'évolution et le mélange des jets latéraux au sein des jets ronds de mélange binaire à faible densité, au moyen d'une double approche numérique et expérimentale. Les mécanismes physiques à l'origine des jets latéraux restent encore incertains et sont en lien direct avec le développement d'instabilités secondaires responsables de la tridimensionalisation de l'écoulement. Ainsi, une meilleure compréhension de ces mécanismes en jeu constitue un prérequis indispensable à la conception d'une stratégie de contrôle qui vise à promouvoir le mélange entre le jet et l'environnement ambiant.L'objectif de l'étude numérique est d'identifier les mécanismes transitoires qui influencent la croissance des perturbations tridimensionnelles dans le jet rond à faible masse volumique, en particulier dans les conditions physiques pour lesquelles apparaissent les jets latéraux. À cet effet, nous mettons en oeuvre une analyse de stabilité linéaire non-modale de l'évolution non-linéaire et axisymétrique de l'anneau tourbillonnaire de Kelvin-Helmholtz qui se développe dans les jets ronds à faible masse volumique en réponse à l'instabilité primaire de Kelvin-Helmholtz. Cette analyse de stabilité est réalisée à l'aide du code académique dalsa qui a été adapté pour ce régime d'écoulement. L'utilisation d'une méthode d’optimisation directe-adjointe permet d'identifier la structure spatiale et l'évolution temporelle des perturbations tridimensionnelles qui maximisent leur gain d'énergie généralisée, ainsi que les mécanismes physiques sous-jacents et leur lien avec l'apparition des jets latéraux. En particulier, l'objectif est d'apporter de nouveaux éléments permettant de statuer entre les deux hypothèses proposées dans la littérature pour expliquer le mécanisme à l'origine des jets latéraux. La première proposée par Monkewitz & Pfizenmaier (1991) repose sur un mécanisme d'induction de vitesse par les tourbillons longitudinaux contra-rotatifs qui se développent dans les écoulement cisaillés à masse volumique constante. La seconde est basée sur le mécanisme de tri-dimensionalisation associé aux stries de vitesse longitudinale de signe opposé qui se développent de part et d'autre du point de stagnation hyperbolique dans la tresse identifiée par Lopez-Zazuetaet al. (2016) dans la couche de mélange plane à densité variable.L'étude numérique conduite dans cette thèse est conçue en lien étroit avec la campagne expérimentale visant à étudier la structure des jets latéraux dans un jet de mélange binaire hélium-air. Ainsi, les paramètres de l'étude numérique comme les nombres de Reynolds et d'Atwood ainsi que le rapport d'aspect du jet, sont basés sur les conditions expérimentales. Ceci permet une comparaison directe des résultats théoriques aux observations expérimentales. Pour ce faire, nous avons conduit une campagne de mesures d'anémométrie à fil chaud du profil radial de vitesse du jet, et de la fréquence de l'instabilité primaire, afin de le caractériser et de le placer dans le contexte de la littérature scientifique.L'objectif de l'approche expérimentale est d'analyser la structure des jets latéraux et le mélange qu'ils induisent. Nous avons ainsi conçu et assemblé un banc de Background Oriented Schlieren tomographique (3DBOS). Ce banc est conçu afin de pouvoir observer les déviations optiques de l'ordre de 0,5 mrad induites par le champ hétérogène d'indices de réfraction créé par le jet de mélange hélium-air. Les mesures de 3DBOS obtenues permettent de reconstruire les champs de masse volumique du jet à faible densité en présence de jets latéraux. Ces champs de masse volumique sont originaux dans la littérature scientifique sur le sujet, et permettent d'augmenter notre compréhension de la structure des jets latéraux et de leur impact sur le mélange, et ainsi de corroborer les prédictions issues de l'analyse de stabilité
The aim of this PhD thesis is to study the physical mechanisms which govern the evolution and the mixing of side-jets in low-density binary mixing round jets, using a complementary numerical and experimental approach. The physical mechanisms which are responsible for the generation of side-jets, closely related to the three-dimensionalisation of the jet through the development of secondary instabilities, are as of yet not fully understood. As such, a better understanding of the mechanisms at play is a prerequisite for the design of an efficient control strategy to promote the mixing between the jet and ambient fluid.The objective of the numerical study is to identify the transient mechanisms which influence the growth of three-dimensional disturbances in the low-density round jet, specifically under the physical conditions in which side-jets appear. To that aim, a linear non-modal stability analysis was conducted over the non-linear evolution of a two dimensional axisymmetric Kelvin-Helmholtz vortex ring which develops in low-density round jets due to the Kelvin-Helmholtz primary instability.The stability analysis was implemented through further numerical development of the existing dalsa academic code. Through the use of a direct-adjoint optimisation method, we identify the spatial structure and temporal evolution of three-dimensional disturbances which yield the highest growth of generalised energy, as well as the underlying physical mechanisms and their relation to side-jets generation in low-density round jets at low Atwood numbers. In particular, we seek to bring a new perspective in order to settle between the two current hypotheses concerning the physical mechanisms at the origin of side-jets. The first hypothesis suggested by Monkewitz & Pfizenmaier (1991) relies on a velocity induction mechanism induced by the longitudinal counter-rotating vortex dipoles developing in the constant-density case. The second one is based on the three-dimensionalisation mechanism associated with longitudinal velocity streaks of opposite sign developing on either side of the hyperbolic stagnation point in the braid identified by Lopez-Zazueta et al. (2016) in the case of variable-density plane mixing layers.The numerical analysis is conducted in close relation to an experimental investigation of the structure of side-jets in a helium-air binary mixture round jet. The parameters used in the numerical analysis, such as the Reynolds number, the Atwood number and jet aspect ratio, are based on the operating conditions used in the experiment, allowing the theoretical predictions to be compared with the empirical evolution of the helium-air jet. To that aim, we conduct hot-wire anemometry measurements of the jet radial profile and frequency of the primary instability under several operating conditions to characterise the evolution of the governing parameters and relate the experimental conditions to the existing scientific literature.The objective of the experimental investigation is to study the structure of side-jets and their effect on the mixing of the jet and ambient fluids. To do so, we have designed and assembled a tomographic Background Oriented Schlieren (3DBOS) experimental bench. This bench is designed to observe the deviations of light-rays of the order of 0.5 mrad induced by the change in refractive index in the helium-air jet. The 3DBOS technique employed in this study provides novel reconstructions of three-dimensional density maps of the side-jets which develop over the helium-air jet. Through these novel density maps, we can provide new insight into the structure of side-jets and their induced mixing, and relate them to the predictions of the stability analysis