Geometrical Study of the Barrel Stave in a Procedure of Restitution of the Original Flat Shape

2021 ◽  
pp. 100-106
Author(s):  
A. Conde Fernández ◽  
E. Zurita de la Vega ◽  
P. Vila Lameiro ◽  
P. Tato-Sánchez del Valle
Keyword(s):  
Flat Shape

Shape memory alloy–actuated prestressed composites with application to morphing automotive fender skirts

2018 ◽  
Vol 30 (3) ◽  
pp. 479-494 ◽  
Author(s):  
Venkata Siva C Chillara ◽  
Leon M Headings ◽  
Ryohei Tsuruta ◽  
Eiji Itakura ◽  
Umesh Gandhi ◽  
...  
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Smart Materials ◽  
Design Procedure ◽  
Building Blocks ◽  
Smart Composite ◽  
Thermally Induced ◽  
One Dimensional ◽  
Flat Shape

This work presents smart laminated composites that enable morphing vehicle structures. Morphing panels can be effective for drag reduction, for example, adaptive fender skirts. Mechanical prestress provides tailored curvature in composites without the drawbacks of thermally induced residual stress. When driven by smart materials such as shape memory alloys, mechanically-prestressed composites can serve as building blocks for morphing structures. An analytical energy-based model is presented to calculate the curved shape of a composite as a function of force applied by an embedded actuator. Shape transition is modeled by providing the actuation force as an input to a one-dimensional thermomechanical constitutive model of a shape memory alloy wire. A design procedure, based on the analytical model, is presented for morphing fender skirts comprising radially configured smart composite elements. A half-scale fender skirt for a compact passenger car is designed, fabricated, and tested. The demonstrator has a domed unactuated shape and morphs to a flat shape when actuated using shape memory alloys. Rapid actuation is demonstrated by coupling shape memory alloys with integrated quick-release latches; the latches reduce actuation time by 95%. The demonstrator is 62% lighter than an equivalent dome-shaped steel fender skirt.

Analytical and Numerical Modelling of Shape Memory Alloy Negator Springs for Long-Stroke Constant-Force Actuators

2012 ◽  
Author(s):  
Andrea Spaggiari ◽  
Eugenio Dragoni
Keyword(s):  
Shape Memory ◽  
Mechanical Behaviour ◽  
Volume Ratio ◽  
Constant Force ◽  
Helical Springs ◽  
Finite Element Software ◽  
Spiral Spring ◽  
High Area ◽  
Flat Shape ◽  
Long Stroke

This paper explores the merits of shape memory Negator springs as powering elements for solid state actuators. A Negator spring is a spiral spring made of strip of metal wound on the flat with an inherent curvature such that, in repose, each coil wraps tightly on its inner neighbour. The unique characteristic of Negator springs is the nearly-constant force needed to unwind the strip for very large, theoretically infinite deflections. Moreover the flat shape, having a high area over volume ratio, grants improved bandwidth compared to any solution with solid wires or helical springs. The SMA material is modelled as elastic in austenitic range while an exponential continuum law is used to describe the martensitic behaviour. The mathematical model of the mechanical behaviour of SMA Negator springs is provided and their performances as active elements in constant-force, long-stroke actuators are assessed. The SMA Negator spring is also simulated in a commercial finite element software, ABAQUS, and its mechanical behaviour is estimated through FE analyses. The analytical and the numerical prediction are in good agreement, both in martensitic and in austenitic range.

Oblique View Cone Beam Tomography for Inspection of Flat-Shape Objects

2004 ◽  
Vol 270-273 ◽  
pp. 1135-1142 ◽  
Author(s):  
Masaki Misawa ◽  
Ion Tiseanu ◽  
Ryusuke Hirashima ◽  
Kazuto Koizumi ◽  
Yasushi Ikeda
Keyword(s):  
Cone Beam ◽  
Oblique View ◽  
Flat Shape ◽  
Cone Beam Tomography

scholarly journals First Tarsometatarsal Joint Shape and Orientation

2018 ◽  
Vol 3 (3) ◽  
pp. 2473011418S0020
Author(s):  
Cesar de Cesar Netto ◽  
Jackson Staggers ◽  
Walter Smith ◽  
Sung Lee ◽  
Sierra Phillips ◽  
...  
Keyword(s):  
Articular Cartilage ◽  
Joint Angle ◽  
Frontal Plane ◽  
Cadaveric Specimen ◽  
X Ray ◽  
Horizontal Orientation ◽  
Medial Cuneiform ◽  
Flat Shape ◽  
Fresh Frozen ◽  
Joint Shape

Category: Bunion Introduction/Purpose: Studies have demonstrated that patients with hallux valgus (HV) deformities have increased mobility in the first tarsometatarsal (TMT) joint. Anatomical factors widely considered to play a role in the instability are shape and frontal plane orientation of the joint. An oblique rather than horizontal orientation of the articular surfaces and a round shape, rather than a flat shape, are believed to predispose to the deformity. The purpose of this study was to assess whether the shape and angulation of the first TMT joint are affected by the positioning of the foot and orientation of the x-ray beam. Methods: Ten adult above knee fresh frozen cadaveric specimens were used, with a mean age of 79.9 (range, 54-88) years. There were no clinical forefoot deformities noted in any of the feet. One of the specimens had moderate ankle arthritis and one had a mild cavus-varus. A radiolucent loading apparatus was built that, allowing neutral positioning of a plantigrade foot and controlled angulation of 5o, 10 o, 15o and 20o in dorsiflexion, plantarflexion, inversion and eversion. Fluoroscopic images were obtained of each cadaveric specimen in all seventeen different positions, with the x-ray beam perpendicular to the floor and aiming to the base of the 1st metatarsal. Two blinded orthopaedic surgeons independently measured the 1st tarsometatarsal (TMT) joint angle and graded the distal articular cartilage of the medial cuneiform as flat or curved. Readers also graded the image quality into assessing the joint into “Low”, “Intermediate” and “Good”. Results: 1st TMT joint angle was 112.92o ± 6.89o. Values were significantly different between cadaveric specimens (p<.0001). There was a tendency for increased valgus angulation of the joint in images positioned in neutral, plantarflexion and inversion and decreased valgus angulation with dorsiflexion and eversion.Regarding the shape of the distal articular cartilage of the medial cuneiform, joints with flat configuration showed significantly increased mean 1st TMT joint angle when compared to curved surfaces (115.9o vs. 110.7o, p<.0001). In 8 out of 10 of the cadaveric specimens (80%) the shape of the 1st TMT joint changed between curved or flat configuration depending on the positioning of the foot. In only 2/10 (20%) the joint configuration remained the same for all different positions (one flat and one curved). Conclusion: Our cadaveric study found that the shape and angulation of the first TMT joint is affected by the positioning of the foot and orientation of the x-ray beam. Clinical usefulness of the 1st TMT radiographic anatomical characteristics is limited and should not influence in the treatment of patients with possible instability the first tarsometatarsal (TMT) joint.

scholarly journals Multi-Habitat Radiomics Unravels Distinct Phenotypic Subtypes of Glioblastoma with Clinical and Genomic Significance

Cancers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1707 ◽  
Author(s):  
Seung Won Choi ◽  
Hwan-Ho Cho ◽  
Harim Koo ◽  
Kyung Rae Cho ◽  
Karl-Heinz Nenning ◽  
...  
Keyword(s):  
Validation Cohort ◽  
Prognostic Biomarker ◽  
Imaging Biomarker ◽  
Survival Prediction ◽  
Weighted Sum ◽  
Consensus Clustering ◽  
Mr Images ◽  
Independent Validation ◽  
Genomic Signatures ◽  
Flat Shape

We aimed to evaluate the potential of radiomics as an imaging biomarker for glioblastoma (GBM) patients and explore the molecular rationale behind radiomics using a radio-genomics approach. A total of 144 primary GBM patients were included in this study (training cohort). Using multi-parametric MR images, radiomics features were extracted from multi-habitats of the tumor. We applied Cox-LASSO algorithm to build a survival prediction model, which we validated using an independent validation cohort. GBM patients were consensus clustered to reveal inherent phenotypic subtypes. GBM patients were successfully stratified by the radiomics risk score, a weighted sum of radiomics features, corroborating the potential of radiomics as a prognostic biomarker. Using consensus clustering, we identified three distinct subtypes which significantly differed in the prognosis (“heterogenous enhancing”, “rim-enhancing necrotic”, and “cystic” subtypes). Transcriptomic traits enriched in individual subtypes were in accordance with imaging phenotypes summarized by radiomics. For example, rim-enhancing necrotic subtype was well described by radiomics profiling (T2 autocorrelation and flat shape) and highlighted by the inflammatory genomic signatures, which well correlated to its phenotypic peculiarity (necrosis). This study showed that imaging subtypes derived from radiomics successfully recapitulated the genomic underpinnings of GBMs and thereby confirmed the feasibility of radiomics as an imaging biomarker for GBM patients with comprehensible biologic annotation.

Investigation of enhancing efficiency and acceleration in a flat shape axial gap motor having high torque characteristic

2017 ◽  
Author(s):  
Ren Tsunata ◽  
Masatsugu Takemoto ◽  
Satoshi Ogasawara ◽  
Asako Watanabe ◽  
Tomoyuki Ueno ◽  
...  
Keyword(s):  
Flat Shape ◽  
High Torque

Survival strategies of Silene tatarica (Caryophyllaceae) in riparian and ruderal habitats

2004 ◽  
Vol 82 (4) ◽  
pp. 491-502 ◽  
Author(s):  
Anne Jäkäläniemi ◽  
Anneli Kauppi ◽  
Antti Pramila ◽  
Kalle Vähätaini
Keyword(s):  
Ground Surface ◽  
Survival Strategies ◽  
Long Distance ◽  
Anatomical Structures ◽  
Riparian Plants ◽  
Vascular Elements ◽  
Flat Shape ◽  
Habitat Properties ◽  
Silene Tatarica ◽  
Disturbed Habitats

Certain morphological and anatomical structures of riparian plants might be important for their survival during the season when they are exposed to severe stress caused by flooding, burial, fluctuating temperatures, and drought. These rare characteristics were studied as related to their ecological consequences in a threatened plant, Silene tatarica (L.) Pers., in riparian and ruderal habitats. The main differences between the habitats were morphological and closely related to the habitat properties, whereas the basic anatomy of structures was similar. After sand burial, most riparian plants formed vertical rhizomes and new meristems by bud ramification in the stem base near the ground surface. Special anatomical structures of fleshy underground stems and roots seem to allow plants to be resilient. Moreover, some primitive structures, such as vascular elements with helical and scalariform thickenings, collenchyma, and abundant xylem parenchyma, may increase the resilience of organs. High amounts of saccharose in fleshy rhizomes and roots can increase the cold resistance of plants. The flat shape and structures of tiny seeds may enhance the long-distance dispersal by water. We suggest that the synergism of these structures enables the survival of S. tatarica in highly disturbed habitats with fluctuating water levels.Key words: bud clusters, burial, flooding, growth habit, tensile strength, vertical rhizome.

Hydrodynamic Resistance Reduction of Multi-Purpose Amphibious Vehicle due to Air Bubble Effect

2016 ◽  
Vol 819 ◽  
pp. 335-340 ◽  
Author(s):  
Adi Maimun ◽  
Mehdi Nakisa ◽  
Yasser M. Ahmed ◽  
Fatemeh Behrouzi ◽  
Koh K. Koh ◽  
...  
Keyword(s):  
Frictional Resistance ◽  
Hydrodynamic Resistance ◽  
Operating Life ◽  
Air Bubble ◽  
Marine Vehicles ◽  
Ansys Cfx ◽  
Flat Shape ◽  
Air Cushion ◽  
Comparative Results ◽  
Pump Compressor

Multipurpose Amphibious Vehicles (MAV) and other blunt shaped floating vehicles encounter the problem of a large bow wave forming and hydrodynamic resistance at high speeds. This wave formation is accompanied by higher resistance and at a critical speed results in bow submerging or swamping. Three new shapes of hull bow design for the multipurpose amphibious vehicle were conducted at several speeds to investigate the hydrodynamic phenomena using Computational Fluid Dynamics (CFD, RANS code), which is applied by Ansys-CFX14.0 and Maxsurf. The vehicle’s hydrodynamic bow shapes were able to break up induced waves and avoid swamping. Comparative results with the vehicle fitted with U-shape, V-shape and Flat-shape of hull bow, showed that the U-shape of the hull bow has reduced the total resistance to 20.3% and 13.6% compared with the V-shape and flat shape respectively. Though, the U-shape of hull bow is capable to increase the amphibious operating life and speed of vehicle. Also it has ability to reduce the vehicle’s required power, fossil fuel consumption and wetted hull surface. On the other hand, the use of air cushions to support marine vehicles, heavy floating structures and in other operation is well known. The main problem in Multi-purpose Amphibious Vehicles (MAV) is the amount of power needed in order to overcome the hydrodynamic resistance acting on the hull which is included the frictional and pressure resistances. Therefore, more power is needed to move the MAV forward. In this respect, more fuel will be required to operate the amphibious vehicles. This problem could be effectively reduced by the introduction of the air cushion concept. With the air being drawn from top of craft to the cavity below the hull will produce some cushioning effect and also help to reduce skin friction drag. In this paper, air cushion effect will be studied in rigid surface cavity instead of using flexible skirts. This would avoid the problem of high maintenance due to replacement of damaged skirts. Finally, the MAV will be supported using air cavity and bubbles generated by an air pump (compressor and air pressure vessel) to pushes the hull of multi-purpose amphibious vehicle up and reduce the frictional resistance due to draft and wetted surface reduction and layer of air between hull surface and water. This research would be done via CFD (ANSYS-CFX 14.0) and analyzed the hydrodynamic resistance

Precision Cutting of Ceramics with Milling Tool of Single Crystalline Diamond

2015 ◽  
Vol 9 (1) ◽  
pp. 26-32 ◽  
Author(s):  
Hirofumi Suzuki ◽  
◽  
Mutsumi Okada ◽  
Koichi Okada ◽  
Yosuke Ito ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Laser Beam ◽  
Tungsten Carbide ◽  
Micro Milling ◽  
Form Accuracy ◽  
Single Crystalline ◽  
Flat Shape ◽  
Ductile Mode ◽  
Milling Tool ◽  
Milling Tools

Micro milling tools made of Single Crystalline Diamond (SCD) have been developed to machine micro dies and molds made of ceramics. The milling tools of a cylindrical SCD having many sharp cutting edges are fabricated 3-dimensionally by scanning a laser beam. Flat shape of binder-less tungsten carbide mold was cut with the developed milling tool to evaluate the tool wears and its life. Some micro aspheric molds of tungsten carbide were cut with the milling tool at a rotational speed of 50,000 min-1. The ceramic molds were cut in the ductile mode. By cutting with the milling tool, the form accuracy obtained was about 100 nm P–V and the surface roughness 8 nm Rz.

Longitudinal Compensation Algorithm for the Stamping Fold Shift of Quadric Metal Curtain Walls

2018 ◽  
Vol 13 (10) ◽  
pp. 1584-1590
Author(s):  
Yalong Zhang ◽  
Xuan Ma ◽  
Xiaodan Jiang ◽  
Hisakazu Ogura
Keyword(s):  
Metal Plate ◽  
Surface Patch ◽  
Small Surface ◽  
Quadric Surfaces ◽  
Surface Patches ◽  
Forming Technology ◽  
Flat Shape ◽  
Building Surfaces ◽  
Asymmetric Stress ◽  
Limiting Case

Metal curtain walls are widely applied as decorative materials for the outer walls of large buildings. However, the application of such materials in curved building surfaces is relatively complicated. The whole curved surface is divided into several small surface patches according to a specific plan. Each surface patch is shaped by stamping with a certain-shaped plane metal plate. The calculation of the flat shape of a given surface patch is a key technology. Quadric surfaces are inextensible surfaces. Flat metal materials are folded when stamped into curved surfaces. Wrinkles are distributed unevenly because the curvature of surface patches is often asymmetric. Stress pushes wrinkles from high-density regions to low-density areas, at which point a uniform distribution pattern is reached under the limiting case. An accurate surface flattening method that compensates for fold shift is regarded as a difficult technology to develop. To address these problems, this study proposed an even flattening method for quadric surfaces. The proposed method simplifies the sheet metal forming technology and achieves satisfactory accuracy in the engineering process.

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