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Than, Thida, Labang Hkawn, Anjuna Radhakrishnan, Yupa Min, Hlaing Thaw Dar e Nurul Hazliana Harun. "Variation in the shape of the knee meniscus and incidence of the discoid shape in Myanmar's adult population: A cross-sectional study". Journal of Biomedical Sciences 10, n. 2 (31 dicembre 2023): 32–39. http://dx.doi.org/10.3126/jbs.v10i2.61357.
Testo completoAbstract (sommario):
Background: A meniscal injury is one of the most common sports-related problems and the most frequent injury to the knee joint. The method for determining meniscus shape is used in designing therapies for treating various joint diseases.
Material and methods: Anatomy dissection was performed, and the shapes of knee menisci were studied in 160 menisci from 40 autopsy bodies (20 males and 20 females) from Medical Universities in Myanmar. The bodies were embalmed with 4% formaldehyde and then preserved in a weak formalin solution.
Results: The number of crescentic-shaped medial menisci was 5 (6.25%), horseshoe-shaped menisci were 6 (7.5%), sickle shapes were 48 (60%), U shapes were 8 (10%), V shapes were 12 (15%), and complete discoid shapes were only 1 in number (1.25%). There was no incomplete discoid, circular, or C shape at all. The commonest shape of the medial meniscus was a sickle. The number of C-shaped lateral menisci was 6 (7.5%), the complete discoid shape was 1 (1.25%), the incomplete discoid shapes were 13 (16.25%), and the circular shapes were 60 (75%). Crescentic, horseshoe, sickle, U, and V-shaped lateral menisci were absent. Circular was the commonest of all. Among 160 menisci, an incomplete discoid shape was found in 13 menisci, and a complete discoid shape was found in two: one meniscus as a primitive disc and a very rare infantile shape in another.
Conclusion: Our findings will help morphologists and orthopaedic surgeons with surgical procedures and knee joint arthroscopy. It will also help patients with effective rehabilitation after meniscal injuries and surgery.
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Bender-Heine, Adam, Michelle Russell, Allen Rickards, J. Holmes, Mark Armeni, H. Lambert e Matthew Zdilla. "Optimal Costal Cartilage Graft Selection According to Cartilage Shape: Anatomical Considerations for Rhinoplasty". Facial Plastic Surgery 33, n. 06 (dicembre 2017): 670–74. http://dx.doi.org/10.1055/s-0037-1607972.
Testo completoAbstract (sommario):
AbstractCostal cartilage grafting is a commonly used reconstruction procedure, particularly in rhinoplasty. Although costal cartilage is broadly used in reconstructive surgery, there are differing opinions regarding which costal cartilage levels provide the most ideal grafts. Grafts are typically designed to match the shape of the recipient site. The shapes of costal cartilage grafts have been described as “boat-shaped,” “C-shaped,” “canoe-shaped,” “U-shaped,” “crescent-shaped,” “L-shaped,” “semilunar,” “straight,” and “Y-shaped.” The shapes of costal cartilages are thought to lend themselves to the shapes of certain grafts; however, there has been little study of the shapes of costal cartilages, and most reports have been anecdotal. Therefore, this study is aimed to detail the average shapes of the most commonly grafted cartilages (i.e., the fifth to seventh cartilages). A total of 96 cadaveric costal cartilages were analyzed through geometric morphometric analysis. The fifth costal cartilage was determined to have the straightest shape and would therefore be particularly suitable for nasal dorsum onlay grafting. The lateral portions of the sixth and, particularly, the seventh costal cartilages have the most acute curvature. Therefore, they would lend themselves to the construction of an en bloc “L”-shaped or hockey stick-shaped nasal dorsum-columellar strut graft.
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Shi, Ding, Feng Ji, Yin-su Bao e Yong-pan Liu. "A Multicenter Randomized Controlled Trial of Malignant Gastric Outlet Obstruction: Tailored Partially Covered Stents (Placed Fluoroscopically) versus Standard Uncovered Stents (Placed Endoscopically)". Gastroenterology Research and Practice 2014 (2014): 1–7. http://dx.doi.org/10.1155/2014/309797.
Testo completoAbstract (sommario):
The aim of our study is to compare the efficacy and safety of “outlet-shape” tailored stents with standard stents for the management of distal gastric cancer causing gastric outlet obstructions (GOOs) with varying gastric cavity shapes and sizes. To determine the shape and size of the GOOs, stomach opacifications were performed using contrast media before stenting. Two basic shapes of the residual cavity of the proximal GOO were observed: cup shaped or approximately cup shaped and funnel shaped or approximately funnel shaped. Other shapes were not found. In the GOO tailored group, the size and shape of the proximal ends of the tailored stent were suited for the residual cavity of the proximal GOO. The tailored stents included large cup-shaped stents and large funnel-shaped stents. GOO tailored covered stents led to less restenosis and reintervention rates compared to standard uncovered stents but with the same survival.
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Ismail, Ikram K., e Abdennour Seibi. "Shape Factors for Irregular Glass Reinforced Plastic Pipes – An Analytical and Numerical Approach". Key Engineering Materials 471-472 (febbraio 2011): 279–84. http://dx.doi.org/10.4028/www.scientific.net/kem.471-472.279.
Testo completoAbstract (sommario):
This paper presents the development of a mathematical model based on curved beam theory of composite pipes with irregular shapes under diametral loading. The analytical solution was validated through finite element models of the same pipe shapes under similar loading conditions. Four shapes (circular, elliptical, rectangular, and egg shaped pipes) were considered in this study. The analytical and finite element results were used to estimate the shape factor defined by the ratio of the maximum tangential stress of an irregular shape over the maximum tangential stress for a circular pipe. Comparison of the load-deflection curves for the four different shapes revealed that the egg pipe is the stiffest among the rest of the pipes while the square shape is the most flexible one. The analytical solution and finite element results were used to determine the shape factor for the four pipe shapes taking into account the circular pipe as the base shape. Both results were in good agreement and can be used as design guidelines for the irregular shapes without resorting to the conduct of any further testing.
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Formby, C. "Simple Triangular Approximations of Auditory Filter Shapes". Journal of Speech, Language, and Hearing Research 33, n. 3 (settembre 1990): 530–39. http://dx.doi.org/10.1044/jshr.3303.530.
Testo completoAbstract (sommario):
At present, the most popular auditory filter shape model is one with a rounded peak and exponentially decaying filter skirts (Patterson & Moore, 1986). Unfortunately, the complex nature of this “roex” filter model may, in some instances, have hindered the application of the auditory filter shape in clinical measurements of frequency selectivity. Moreover, some of the assumptions of the roex filter model may be violated at high sound-pressure levels (SPLs) and this limitation has also been a factor when considering the roex auditory filter shape in the clinic. Our purpose is to introduce a simplified method that is adequate for obtaining clinically useful estimates of triangular-shaped auditory filters. Although the triangular-shaped filter model faces the same problems as the roex model at high SPLs, the calculations and assumptions underlying the former are far less complicated. The triangular filter model also retains many of the qualitative properties and advantages afforded by roex-fitted auditory filter shapes. In this report, we review the basic concepts underlying auditory filter shape estimates and describe our methods for measuring and fitting the triangular-shaped filter model. We then present normative triangular filter shapes and compare these estimates with auditory filter shapes fitted by other means. Finally, we present selected examples of triangular filter shapes fitted to the masked thresholds of hearing-impaired patients. For the most part, the triangular-shaped filter model offers the clinician a satisfactory compromise for obtaining estimates of auditory filter shape and frequency selectivity at moderately intense and high SPLs.
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Tanveer, Muhammad, e Kwang-Yong Kim. "Effects of Bridge-Shaped Microchannel Geometry on the Performance of a Micro Laminar Flow Fuel Cell". Micromachines 10, n. 12 (27 novembre 2019): 822. http://dx.doi.org/10.3390/mi10120822.
Testo completoAbstract (sommario):
A laminar flow micro fuel cell comprising of bridge-shaped microchannel is investigated to find out the effects of the cross-section shape of the microchannel on the performance. A parametric study is performed by varying the heights and widths of the channel and bridge shape. Nine different microchannel cross-section shapes are evaluated to find effective microchannel cross-sections by combining three bridge shapes with three channel shapes. A three-dimensional fully coupled numerical model is used to calculate the fuel cell’s performance. Navier-Stokes, convection and diffusion, and Butler-Volmer equations are implemented using the numerical model. A narrow channel with a wide bridge shape shows the best performance among the tested nine cross-sectional shapes, which is increased by about 78% compared to the square channel with the square bridge shape.
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Du, Shigui, Yunjin Hu e Xiaofei Hu. "Generalized Models for Rock Joint Surface Shapes". Scientific World Journal 2014 (2014): 1–7. http://dx.doi.org/10.1155/2014/171873.
Testo completoAbstract (sommario):
Generalized models of joint surface shapes are the foundation for mechanism studies on the mechanical effects of rock joint surface shapes. Based on extensive field investigations of rock joint surface shapes, generalized models for three level shapes named macroscopic outline, surface undulating shape, and microcosmic roughness were established through statistical analyses of 20,078 rock joint surface profiles. The relative amplitude of profile curves was used as a borderline for the division of different level shapes. The study results show that the macroscopic outline has three basic features such as planar, arc-shaped, and stepped; the surface undulating shape has three basic features such as planar, undulating, and stepped; and the microcosmic roughness has two basic features such as smooth and rough.
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Zhao, Mingxin, Wentai Sun, Hongxu Li, Wei Wang, Gang Cao e Falin Wang. "The Effects of the Tree Structure of Zaosu Pear on the Transport and Distribution of Photosynthetic Assimilates and Fruit Quality under Desert-Area Conditions". Agronomy 12, n. 10 (8 ottobre 2022): 2440. http://dx.doi.org/10.3390/agronomy12102440.
Testo completoAbstract (sommario):
Pear is an important fruit tree in China, and the Hexi area is the main pear-planting area in Gansu Province. Tree shapes have different effects on photosynthesis that influence fruit quality and development. Thus, in the current study, five tree shapes of Zaosu pear, including the Y-shaped, trunk, single-arm, double-arm, and spindle tree shapes, were selected, and their effects on photosynthesis and fruit quality were investigated. The thickness and length of shoot branches were highest in the single-, double-arm, and spindle tree shapes. The level of photosynthetically active radiation (PAR) varied by tree shape; from highest to lowest, the order was double-arm > single-arm > spindle > Y-shaped > trunk tree shapes. Leaf area and chlorophyll content were highest in the single- and double-arm tree shapes, with higher increases in the net photosynthetic rate to light intensity (Pn-PAR), the net photosynthetic rate to CO2 (Pn-CO2), the relative variable fluorescence (Vj), PSⅡ maximum photochemical efficiency (Fv/Fm), and the light energy absorbed per unit reaction centre (ABS/RC). For fruit quality, the fruit shape index, fruit colour parameters, and content of soluble solids increased significantly in the single- and double-arm tree shapes, while the content of total acids, malic acid, and citric acid in the single- and double-arm tree shapes was lower than in the other tree shapes. All these results demonstrated that the single- and double-arm tree shapes are well ventilated and light-transmitting, which can promote fruit growth and quality.
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Žalik , Borut, Damjan Strnad , David Podgorelec , Ivana Kolingerová , Andrej Nerat , Niko Lukač , Štefan Kohek e Luka Lukač . "Geometric Shape Characterisation Based on a Multi-Sweeping Paradigm". Symmetry 15, n. 6 (6 giugno 2023): 1212. http://dx.doi.org/10.3390/sym15061212.
Testo completoAbstract (sommario):
The characterisation of geometric shapes produces their concise description and is, therefore, important for subsequent analyses, for example in Computer Vision, Machine Learning, or shape matching. A new method for extracting characterisation vectors of 2D geometric shapes is proposed in this paper. The shape of interest, embedded into a raster space, is swept several times by sweep-lines having different slopes. The interior shape’s points, being in the middle of its boundary and laying on the actual sweep-line, are identified at each stage of the sweeping process. The midpoints are then connected iteratively into chains. The chains are filtered, vectorised, and normalised. The obtained polylines from the vectorisation step are used to design the shape’s characterisation vector for further application-specific analyses. The proposed method was verified on numerous shapes, where single- and multi-threaded implementations were compared. Finally, characterisation vectors, among which some were rotated and scaled, were determined for these shapes. The proposed method demonstrated a good rotation- and scaling-invariant identification of equal shapes.
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Kumar, Raj. "Variations in the shape of foramen magnum at the base of human skulls among Indians in Rajasthan". Bioinformation 18, n. 5 (31 maggio 2022): 488–91. http://dx.doi.org/10.6026/97320630018488.
Testo completoAbstract (sommario):
Variations in the shape of foramen magnum can affect the normal anatomy of vital structures passing through it. Therefore, it is of interest to evaluate the various shapes of foramen magnum by using CT scans performed in patients of Indian population to establish clinical correlation. A total of 314 CT images of human skull base obtained from the Department of Radio-diagnosis, Geetanjali Medical College and Hospital, Udaipur, Rajasthan were used in the present study. All the patients’ CT scans were observed to determine the shape of foramen magnum. They were classified into one of the following shapes: Oval, round, tetragonal, egg shaped, hexagonal, pentagonal and irregular. The shapes of the foramen magnum in CT scans were oval in 39.09%, round in 22.61%, tetragonal in 12.10%, hexagonal in 10.51%, irregular in 7.96%, pentagonal in 5.41% and egg shaped in 1.59% CT images. Data shows that it is easy to operate at the base of skull in case of round, oval and hexagonal shape foramen magnum, as the working space is more in these shapes.
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McCane, Brendan. "Shape Variation in Outline Shapes". Systematic Biology 62, n. 1 (8 novembre 2012): 134–46. http://dx.doi.org/10.1093/sysbio/sys080.
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N, Durairaj, Karthikeyan A. K., Praveen M. S, Karthi B e Dhivakaran S. "Theoretical Study of Solar Dryer with Different Shapes of Absorber Plate". International Journal for Research in Applied Science and Engineering Technology 10, n. 8 (31 agosto 2022): 1964–68. http://dx.doi.org/10.22214/ijraset.2022.46574.
Testo completoAbstract (sommario):
Abstract: This paper presents a theoretical to implemented different shapes of two types of absorber plate (twisted shaped, uniformly increase v-shaped) in solar flat plate collector. Using different shapes noted and tested, which one get more drying efficiency, thermal efficiency with the help of theoretical using formulation and compared to the analytical results. Lets also discussed advantages of the shape of absorber plate.
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Zabarankin, Michael. "Minimum-resistance shapes in linear continuum mechanics". Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 469, n. 2160 (8 dicembre 2013): 20130206. http://dx.doi.org/10.1098/rspa.2013.0206.
Testo completoAbstract (sommario):
A necessary optimality condition for the problem of the minimum-resistance shape for a rigid three-dimensional inclusion displaced in an unbounded isotropic elastic medium subject to a constraint on the volume of the inclusion is obtained through Betti's reciprocal work theorem. It generalizes Pironneau's optimality condition for the minimum-drag shape for a rigid body immersed into a uniform Stokes flow and is specialized for axisymmetric inclusions in axisymmetric and transversal translations. In both cases of translation, the three-dimensional displacement field is represented in terms of generalized analytic functions, and the three-dimensional elastostatics problem is reduced to boundary-integral equations (BIEs) via the generalized Cauchy integral formula. Minimum-resistance shapes are found in the semi-analytical form of functional series from an iterative procedure coupling the optimality condition and the BIEs. They are compared with the minimum-resistance spheroids and with the minimum-resistance spindle-shaped and lens-shaped bodies. Remarkably, in the axisymmetric translation, the minimum-resistance shapes transition from spindle-like shapes to almost prolate spheroidal shapes as the Poisson ratio changes from 1/2 to 0, whereas in the transversal translation, they are close to oblate spheroidal shapes for any Poisson ratio.
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Baechler, J., C. A. Beck e W. D. Bowen. "Dive shapes reveal temporal changes in the foraging behaviour of different age and sex classes of harbour seals (Phoca vitulina)". Canadian Journal of Zoology 80, n. 9 (1 settembre 2002): 1569–77. http://dx.doi.org/10.1139/z02-150.
Testo completoAbstract (sommario):
Classifying dives into two-dimensional shapes based on time and depth is an attempt to extract additional information about the behaviour of aquatic air-breathing predators. In some species, there is considerable circumstantial evidence that different dive shapes represent different behaviours. However, few studies have provided direct evidence of the relationship between dive shape and function. We classified over 283 000 dives of adults (31 males and 45 females) and suckling (13) and recently weaned (15) harbour seal (Phoca vitulina) pups into seven shapes using supervised discriminant function analysis. Changes in the percentage of U-shaped dives over time within adults and weaned pups were associated with changes in food intake derived from water-flux studies on subsets of the same individuals. The changes in the percentage of U-shaped dives were accompanied by roughly reciprocal changes in V-shaped dives, whereas there was little change in other dive shapes, indicating that V-shaped dives are not generally exhibited during foraging. Video of adult males (from an animal-borne video system) also showed that there was a strong but not exclusive association between foraging and U-shaped dives. Our results indicate that changes in the percentage of U-shaped dives may serve as a reasonable index of changes in foraging behaviour. However, behaviours of suckling pups and adult males during the breeding season cannot be easily inferred from dive shape alone.
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Kumar B., Varun, G. Manikandan, P. Kanna, Dawid Taler, Jan Taler, Marzena Nowak-Ocłoń, Karol Mzyk e Hoong Toh. "A Performance Evaluation of a Solar Air Heater Using Different Shaped Ribs Mounted on the Absorber Plate—A Review". Energies 11, n. 11 (9 novembre 2018): 3104. http://dx.doi.org/10.3390/en11113104.
Testo completoAbstract (sommario):
In this paper, the effect of various shapes of ribs used in Solar Air Heaters (SAHs) was discussed. The review is concentrated on the geometry of the rib and its location on the SAH panel. Both numerical and experimental works were considered for discussion with dry air and Nano fluids as a working fluid. The influence of various shapes, such as an L shape, W shape, V shape, Multiple V shape, V shape with a gap, detachable & attachable ribs etc., was analyzed. The common fact observed from this analysis is that the implementation of artificial roughness in the absorber plate results in a considerable increase in the rate of heat transfer. Further, it is observed that ‘Multiple V-shaped with open between the ribs’ results in the maximum thermal enhancement when compared to the other shapes.
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Asha, S. K., G. Sunitha e Chandrashekhar M. Hadapad. "Different shapes of nanoparticles on peristaltic transport of a Casson fluid in the presence of MHD, thermal radiation and Porous medium". International Journal of Computational Materials Science and Engineering 10, n. 02 (13 maggio 2021): 2150008. http://dx.doi.org/10.1142/s2047684121500081.
Testo completoAbstract (sommario):
The influence of different shapes of nanoparticles on peristaltic flow of Casson fluid in an asymmetric channel is studied in this paper. The suspension of Copper oxide nanoparticles of needle, platelet and lamina shapes is taken into account. The problem is modeled in partial differential equations with suitable slip boundary conditions. The standard nonlinear equations are solved by the Homotopy Analysis Method in Mathematica Software. The influences of different shapes of nanoparticles on concentration, velocity profile and temperature profile are analyzed through the graphs. It is observed that the different shape of nanoparticles has different thermal conductivity, but the lamina shaped nanoparticles have high thermal conductivity as compared to needle and platelet shaped nanoparticles.
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Phuong, Lam-Huy, Cao-Minh Dai, Quach-Ngo Diem-Phuong e Tran-Quoc Tan. "Comparing of antioxidant ability, α-glucosidase inhibition and cytotoxicity of three fruiting body shapes of Ganoderma lingzhi". Research Journal of Biotechnology 18, n. 8 (15 luglio 2023): 119–27. http://dx.doi.org/10.25303/1808rjbt1190127.
Testo completoAbstract (sommario):
In the process of artificial culture, Ganoderma mushrooms will appear with several different shapes of fruiting bodies, even though they share the same species. The differences in shape can influence and create differences in bioactivity and active ingredients. This study looked at the biological activities of ethanol crude extracts from three shape kinds of fruiting bodies of Ganoderma lingzhi mushroom and herb tablets made from kidney-shaped fruiting body including antioxidant, α-glucosidase inhibition and cytotoxic activity in some cell lines. Besides, the content of ganoderic acid A was also evaluated among the tested samples. The results showed that different shapes of G. lingzhi could possess differences in bioactivities. The shapes with elongated fruiting body stem including antler- and intermediate form, have better antioxidant and α-glucosidase inhibitory capacity than the common kidney shape. Furthermore, the antler and intermediate forms' cytotoxic activity against cell lines including fibroblast, NCI H469 and Hep G2, were higher than the kidney-shaped mushroom extracts. Similarly, the results of ganoderic acid A content from the extracts of antler- and intermediate form samples were also higher than that of the other form. Meanwhile, the herb tablets had the same pattern to the kidney-shaped extract in several activities. The ganoderic acid A content of the tablet sample was lower than that of three samples extracted from different mushroom shapes. Interestingly, the tablets showed the best-reducing power among the investigated samples.
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MUHAMAD, ZULKIFLI, CHIK AIMAN, ZAHID BILAL e YAHYA MOHAMAD. "Effects of impactors’ shape on three-dimensional woven fabric composites at low-velocity impacts". Industria Textila 73, n. 06 (20 dicembre 2022): 621–26. http://dx.doi.org/10.35530/it.073.06.202193.
Testo completoAbstract (sommario):
This study investigated the fabric resistance of three-dimensional (3D) woven fibreglass composites generated by impactors of three shapes, i.e., hemispherical, conical, and ogival, on four types of composite structures. Composites were fabricated using the hand lay-up technique. Crimp and mechanical impact resistance tests were carried out in accordance with ASTM D2444 standards and ASTM D3883-04, respectively. The four-floating interlocked (4FLL) yielded the strongest fabric damage tolerance for all the three types of impactors’ shapes with 6.3 kN for the hemispherical shape, 4 kN for the conically shaped, and 3.8 kN for the ogival shape. Additionally, the 4FLL generated a fabric crimp of 3.5% and 2.8% on both fabric directions. The post-impact damage showed that the ogival shape impactor penetrated samples of woven composites better than the conical and hemispherical shapes.
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Castonguay, Martin, Patrick Simard e Pierre Gagnon. "Usefulness of Fourier Analysis of Otolith Shape for Atlantic Mackerel (Scomber scombrus) Stock Discrimination". Canadian Journal of Fisheries and Aquatic Sciences 48, n. 2 (1 febbraio 1991): 296–302. http://dx.doi.org/10.1139/f91-041.
Testo completoAbstract (sommario):
We compared shapes of Atlantic mackerel (Scomber scombrus) sagittae between the two contingents (i.e. spawning groups) from the Northwest Atlantic and between the stocks from the Northwest Atlantic and the North Sea to evaluate whether otolith shape could differentiate between the two contingents in a mixed fishery. We quantified shapes with the Fourier series, an objective and rapid method which decomposes a shape's outline into a series of sinusoids. To determine a correct way to compare contingents/stocks, we first assessed four intracontingent effects on otolith shapes. Age and year-class effects were significant, while sex and bilateral position effects were not. This temporal instability in shapes indicates that confounding effects of age and year-class on otolith shapes need to be assessed carefully before drawing conclusions on stock structure. It also shows that comparative studies of otolith shapes with Fourier descriptors are not useful for mackerel contingent discrimination. The power of discriminant functions to correctly classify test mackerel samples separated by age and sampling year, on the basis of otolith shape, was better for comparisons between the stocks than for those between the contingents.
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Usacheva, Irina V., Ivan A. Spiridonov e Olga N. Korochkova. "SETTING THE STAGE: ENEOLITHIC AND BRONZE AGE LITHIC INDUSTRY MARKERS IN THE MOUNTAIN-FOREST TRANS-URALS". Ural Historical Journal 79, n. 2 (2023): 116–26. http://dx.doi.org/10.30759/1728-9718-2023-2(79)-116-126.
Testo completoAbstract (sommario):
The authors propose to discuss the methodology of searching for the defi nitive indicators of flaking techniques of the Eneolithic — Bronze Age in the mountain-forest Trans-Urals. The methodology is based on a step-by-step cross-referencing analysis of raw materials, technological and morphological characteristics of stone artifacts. The multilayer settlement Shaitanskoe 4–6 stone tools assemblage (the Kirovgrad district, Sverdlovsk Oblast) served as the main resource for the analysis. Main stages of the site’s populating correlated with the Eneolithic and the Bronze Age (Cherkaskul culture). Arrowheads were chosen as the key category of artifacts. This choice was based on both the large number of these artifacts (more than 100 items) and their fairly reliable cultural and chronological verification by the well-known interments and single-layer sites of the Urals and the adjacent territories. The Eneolithic flaking technique demonstrated a pronounced variability of tools. Pressure flaking technique used for obtaining blanks of a certain type (blades, microblades, and flakes of preset shapes and sizes) formed the lithic industry basis. During the Bronze Age, the emphasis shifted towards biface-production-oriented striking and counter striking knapping techniques. One of the Bronze Age lithic industry markers was a significant amount of characteristic waste, defected and good blanks as opposed to a small group of two-sided retouched tools with a high level of standardization and manufacturing quality (arrowheads, knives of an asymmetrical triangular shape with an arc-shaped side blade, scrapers of geometric shapes, etc.). The Eneolithic population preferred siliceous and clay shales, high-quality homogeneous jaspers, some types of chalcedony of gray and yellow, homogeneous flint of greenish and greenish-gray shades, and rhyolites of similar colors. During the Bronze Age, most popular materials were mottled flint of mediocre quality, siliceous shales of dark shades, siliceous quartz and chalcedony of light tones, and some varieties of jasper.
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BANERJEE, MOLOY K., DEBABRATA NAG, RANJAN GANGULY e AMITAVA DATTA. "HEMODYNAMICS IN STENOSED ARTERIES — EFFECTS OF STENOSIS SHAPES". International Journal of Computational Methods 07, n. 03 (settembre 2010): 397–419. http://dx.doi.org/10.1142/s021987621000226x.
Testo completoAbstract (sommario):
A numerical analysis has been carried out to investigate the hemodynamic flow through stenosed arteries having mild (S = 25%) to severe (S = 65%) occlusions and under different regimes of flow Reynolds numbers ( Re ) ranging from 50 to 400. Influence of different stenosis shapes (rectangular, trapezoidal, cosine, and Gaussian) on key hemodynamic parameters e.g., recirculation length, wall shear stress (WSS), pressure drop, and irreversible pressure loss coefficient (C I ) are studied. It has been observed that for S = 25%, no flow separation takes place with cosine and Gaussian shaped stenoses for all the Re values considered, while for rectangular or trapezoidal shapes the flow begins to separate at Re = 400. At higher degrees of stenosis, post-stenotic recirculation is noticed for all the shapes considered — the largest recirculation length being observed with the rectangular shape. The peak centerline velocity in the stenosed region is more sensitive to a change in the degree of occlusion for rectangular stenosis than the other shapes. From the study, it is also revealed that the irreversible pressure loss coefficient (C I ) is the maximum for rectangular shaped stenosis, while it is the least for Gaussian shape. It is observed that at high Re regime, C I becomes insensitive to Re values and can be approximated to be a function of the degree of stenosis (S) and the stenosis shape only.
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Kiliani, J., G. Baumgarten, F. J. Lübken e U. Berger. "Impact of particle shape on the morphology of noctilucent clouds". Atmospheric Chemistry and Physics Discussions 15, n. 11 (15 giugno 2015): 16019–48. http://dx.doi.org/10.5194/acpd-15-16019-2015.
Testo completoAbstract (sommario):
Abstract. Noctilucent clouds (NLC) occur during summer in the polar region at altitudes around 83 km. They consist of ice particles with a typical size around 50 nm. The shape of NLC particles is less well known, but important both for interpreting optical measurements and modeling ice cloud characteristics. In this paper, NLC modeling is adapted to use cylindrical instead of spherical particle shape. The optical properties of the resulting ice clouds are compared directly to NLC 3-color measurements by the ALOMAR RMR-Lidar between 1998 and 2014. Shape distributions including both needle- and disc-shaped particles are consistent with lidar measurements. The best agreement occurs if disc shapes are 60 % more common than needles, with a mean axis ratio of 2.8. Cylindrical particles cause stronger ice clouds on average than spherical shapes by ≈ 30 %, this difference is less pronounced for bright than for weak ice clouds. Cylindrical shapes also cause NLC to have larger but a smaller number of ice particles than for spherical shapes.
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Wu, Rundi, e Changxi Zheng. "Learning to Generate 3D Shapes from a Single Example". ACM Transactions on Graphics 41, n. 6 (30 novembre 2022): 1–19. http://dx.doi.org/10.1145/3550454.3555480.
Testo completoAbstract (sommario):
Existing generative models for 3D shapes are typically trained on a large 3D dataset, often of a specific object category. In this paper, we investigate the deep generative model that learns from only a single reference 3D shape. Specifically, we present a multi-scale GAN-based model designed to capture the input shape's geometric features across a range of spatial scales. To avoid large memory and computational cost induced by operating on the 3D volume, we build our generator atop the tri-plane hybrid representation, which requires only 2D convolutions. We train our generative model on a voxel pyramid of the reference shape, without the need of any external supervision or manual annotation. Once trained, our model can generate diverse and high-quality 3D shapes possibly of different sizes and aspect ratios. The resulting shapes present variations across different scales, and at the same time retain the global structure of the reference shape. Through extensive evaluation, both qualitative and quantitative, we demonstrate that our model can generate 3D shapes of various types. 1
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LES, ZBIGNIEW. "SHAPE UNDERSTANDING: POSSIBLE CLASSES OF SHAPES". International Journal of Shape Modeling 07, n. 01 (giugno 2001): 75–109. http://dx.doi.org/10.1142/s0218654301000060.
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Yifeng Jiang, Jun Xie e Hung-Tat Tsui. "Shape Registration by Optimally Coding Shapes". IEEE Transactions on Information Technology in Biomedicine 12, n. 5 (settembre 2008): 627–35. http://dx.doi.org/10.1109/titb.2008.920798.
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Jowers, Iestyn, Chris Earl e George Stiny. "Shapes, structures and shape grammar implementation". Computer-Aided Design 111 (giugno 2019): 80–92. http://dx.doi.org/10.1016/j.cad.2019.02.001.
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Anilkumar, P. M., A. Haldar, S. Scheffler, B. N. Rao e R. Rolfes. "Numerical Studies on the Design of Self-Resetting Active Bistable Cross-Shaped Structure for Morphing Applications". Proceedings 64, n. 1 (20 novembre 2020): 16. http://dx.doi.org/10.3390/iecat2020-08482.
Testo completoAbstract (sommario):
Multistable structures that possess more than one elastically stable equilibrium state are highly attractive for advanced shape-changing (morphing) applications due to the nominal control effort required to maintain the structure in any of its specific stable shapes. The aim of the paper is to develop a bistable cross-shaped structure consisting of symmetric and unsymmetric laminate actuated using Macro Fibre Composite (MFC) actuators. The critical snap-through voltages required to change the shapes are investigated in a commercially available finite element package. The use of MFC actuators to snap the bistable laminate from one equilibrium shape to another and back again (self-resetting) is demonstrated. A new cross-shaped design of active bistable laminate with MFC actuators is proposed where the cross-shape consist of four rectangles on the four legs and a square on the middle portion. All the rectangles are made up of unsymmetric laminates, and the central portion is designed with a symmetric laminate. MFC actuators are bonded on both sides of the four legs to trigger snap-through and snap-back actions. An attempt is made to address the possible design difficulties arising from the additional stiffness contribution by MFC layers on the naturally cured equilibrium shapes of cross-shaped bistable laminates.
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Sakya, Pranay Ratna, Rinky Nyachhyon, Amita Pradhan, Ratina Tamrakar e Sudeep Acharya. "MORPHOLOGY OF CONDYLE- A RADIOGRAPHIC STUDY". Journal of Chitwan Medical College 12, n. 1 (15 marzo 2022): 17–20. http://dx.doi.org/10.54530/jcmc.636.
Testo completoAbstract (sommario):
Background: Mandibular condyle has a variety of morphology. The changes in their shape and size has been attributed to ageing process, developmental abnormalities, distinct diseases, trauma, endocrine shock, radio therapy etc. Panoramic radiographs remain the easiest, safest and most cost-effective screening modality for temporomandibular joint abnormalities. The study aimed to assess the different shapes of condyles using orthopantomograms from the archives of the hospital data. The variations among the sexes and between the right and left sides of an individual were also determined. Methods: This retrospective study was conducted at People’s Dental College and Hospital within the time period of 1 year (November 2019- November 2020). Orthopantomogram of patients falling within the inclusion criteria were studied. The different shapes of condylar process were traced using marker pencil for both right and left sides. Data collected was entered in Microsoft Office Excel sheet 2013-- and calculated in SPSS version 24 and analyzed using descriptive statistics. Results: Out of the 874 mandibular condyles of 437 patients, the most common was the oval shaped in both the right (275) and the left sides (277), followed by bird beak, diamond, flat and crooked finger respectively. The oval shaped condyle appeared to be predominant in both sexes. The flat shaped and diamond shaped condyle appeared to be a rarity. Conclusions: The most common shape of condyle was found to be oval shape bilaterally and in both genders. Least observed shapes of condyle were flat shape in female patients and diamond shape in male patients.
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Drushel, R. F., D. M. Neustadter, L. L. Shallenberger, P. E. Crago e H. J. Chiel. "The kinematics of swallowing in the buccal mass of Aplysia californica." Journal of Experimental Biology 200, n. 4 (1 febbraio 1997): 735–52. http://dx.doi.org/10.1242/jeb.200.4.735.
Testo completoAbstract (sommario):
Changes in the positions, shapes and movements of the feeding apparatus (buccal mass) of the marine mollusc Aplysia californica were studied in intact, transilluminated juveniles. The buccal mass assumes characteristic shapes as its internal structure, the radula/odontophore, moves anteriorly (protracts) or posteriorly (retracts). These shapes are especially distinctive when the radula/odontophore has protracted forwards fully, is close to its resting or neutral position, or has retracted backwards fully. We refer to the shapes that occur at full protraction, transition and full retraction as shape 1 (spherical), shape 2 (ovoid) and shape 3 (gamma-shaped), respectively. We introduce this shape nomenclature in order to avoid confusion with the existing terms protraction and retraction, which we reserve exclusively to describe the direction of movement of the radula/odontophore. The observed shape changes do not agree with those predicted on the basis of in vitro observations of a feeding head preparation, but are similar to shapes observed in vitro in the snail Lymnaea stagnalis. The buccal mass also rotates approximately 10 degrees dorsally during retraction, pivoting on the attachment to the mouth, before the subsequent protraction and return of the buccal mass to the transition shape. This rotation may be due to activation of the extrinsic muscles of the buccal mass. Plots of the buccal mass shape parameters eccentricity versus ellipticity create a two-dimensional shape space, which accurately quantifies the subtle transitions of shape between the different phases of the feeding cycle. Quantitative differences are observed between pure swallows and swallows with tearing behavior, but the qualitative shapes are similar. Hysteresis in the shape space plots of most swallows provides evidence for the hypothesis that protraction and retraction each have distinct 'active' and 'return' phases. The observed kinematic pattern imposes constraints on the internal structures of the buccal mass and may be used to infer the shape and positions of the radula and odontophore.
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Lemkecher, Fatma, Ludovic Chatellier, Dominique Courret e Laurent David. "Contribution of Different Elements of Inclined Trash Racks to Head Losses Modeling". Water 12, n. 4 (29 marzo 2020): 966. http://dx.doi.org/10.3390/w12040966.
Testo completoAbstract (sommario):
Low bar spacing trash racks have been widely investigated in order to guide fish toward bypasses. In addition to this biological function, the formulae to predict head losses, for hydropower plants, are still being discussed. This paper investigates and models the global head losses generated by inclined trash racks with six different bar shapes and two different supports, in an open channel for six angles and two low bar spacings. The girders that supported the trash racks were U-shaped and different profile shapes. In addition to the previously studied rectangular and “hydrodynamic” bars, four new bar shapes, combining different leading and trailing edges, were investigated. Water depths were measured upstream and downstream of the rack for each configuration, and head loss coefficients were characterized and modeled. Three of these new bar shapes generated lower head losses than the hydrodynamic bar shape. The most efficient bar profile reduced the shape coefficient by 40% compared to the hydrodynamic profile and by 67% compared to the conventional rectangular profile. Concerning the supports, the use of a profiled girder to replace a conventional U-shaped girder also significantly reduced the head losses. The addition of the girder effect in a global formula increased its accuracy in predicting head losses of inclined trash racks upstream of hydropower plants.
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Peng, Yongli, Zhengyi Kong, Ba Huu Dinh, Huu-Hue Nguyen, Truong-Son Cao, George Papazafeiropoulos e Quang-Viet Vu. "Web Bend-Buckling of Steel Plate Girders Reinforced by Two Longitudinal Stiffeners with Various Cross-Section Shapes". Metals 13, n. 2 (5 febbraio 2023): 323. http://dx.doi.org/10.3390/met13020323.
Testo completoAbstract (sommario):
This work performs an investigation into the optimal position of two longitudinal stiffeners with different cross-section shapes such as open section (L-shaped and T-shaped) and closed section (rectangular and triangular shapes) shapes of stiffened plate girders under bending loading through an optimization procedure using a gradient-based interior point (IP) optimization algorithm. The stiffener optimum locations are found by maximizing the bend-buckling coefficient, kb, generated from eigenvalue buckling analyses in Abaqus. The optimization procedure efficiently combines the finite element method and the IP optimization algorithm and is implemented using the Abaqus2Matlab toolbox which allows for the transfer of data between Matlab and Abaqus and vice versa. It is found that the proposed methodology can lead to the optimum design of the steel plate girder for all stiffener cross-section types with an acceptable accuracy and a reduced computational effort. Based on the optimization results, the optimum positions of two longitudinal stiffeners with various cross-section shapes are presented for the first time. It is reported that the optimum locations of two longitudinal stiffeners with open cross-section shapes (T- and L-shaped) are similar to that of flat cross-section, while the optimum positions of two longitudinal stiffeners with closed cross-section types (rectangular and triangular sections) are slightly different. One of the main findings of this study is that the bend-buckling coefficient of the stiffened girder having stiffeners with triangular cross-section shape is highest while that with flat cross-section shape is lowest among all considered stiffener types and this latter case has minimum requirement regarding the web thickness.
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Xia, Wei, Huan Yang e Jian Min Zeng. "Research on Methods of Sheet Blank Shape Optimization for Drawing of Complex Special-Shaped Boxes". Advanced Materials Research 399-401 (novembre 2011): 1826–31. http://dx.doi.org/10.4028/www.scientific.net/amr.399-401.1826.
Testo completoAbstract (sommario):
The reasonable blank shape is very important for drawing forming quality of sheet. In this paper, the blank shape is obtained by inverse calculation based on final drawing workpiece, with finite element software. The optimal blank contour is determined by modifying the 3D models of final drawing workpiece and comparing with forming quality of the different inverse calculated blank shapes, according to the stress and the material flow law in drawing process. The results show that, in the case of the given shapes of workpiece, the blank shapes with high precision can be obtained, the formability becomes better, and the number of drawing forming can be reduced by using the method. The method may also contribute to the drawing of large and medium-sized panels, rectangular boxes and special-shaped parts.
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Covantev, Serghei, Rasul Uzdenov, Daria Turovets e Olga Belic. "Spleen: an organ of multiple shapes". Iberoamerican Journal of Medicine 3, n. 4 (5 ottobre 2021): 326–31. http://dx.doi.org/10.53986/ibjm.2021.0052.
Testo completoAbstract (sommario):
Introduction: The spleen is located in the upper part of the abdominal cavity. As an organ, the spleen can have various shapes and size. Material and methods: The human spleen was studied in 273 cadavers (154 men and 119 women) who did not have diseases of the spleen. The shape of the spleen was analyzed based on splenic index, Michels classification. Results: The most common shape of the spleen in men is the elongated one. It was encountered in 79 (51.3%) cases out of 154. In women, the most common shape was the intermediate. It was encountered in 51 (42.9%) of the 119 cases. Based on Michels classification the clinoid (wedge) shape was encountered in 102 (37.74%) cases, triangular in 59 (21.83%) and tetrahedral in 30 (11.1%). In 30.26% the shape of the spleen couldn’t be classified according to Michels classification. In 21 cases (7.77%) the spleen had a flat shape; in 27 (9.99%) – dome-shaped; in 1 case (0,37%) – Z-shape; in 18 (6.66%) – round shape; in 6 (2.22%) – irregular shape; in 2 (0.66%) - shape with a node in the hilum; in 1 (0,37%) – rhomboid shape, in 2 (0,74%) – bilobed shape and in 4 cases (1,48%) – lobular shape. The splenic fissures located on the upper edge of the organ were found in 81 (29.91%) cases, and also on the lower edge - in 41 (14.02%) cases. In 13 (4.67%) cases fissures were encountered on both sides. In 148 (51.4%) cases the spleen had no fissures on its surface. Conclusions: The spleen has various shapes beyond the classical wedge, triangular and tetrahedral. All of these shapes do not represent a pathological finding but in certain situation may require further analysis and interpretation depending on the imaging technique and experience of the physician.
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Sreenivasagan, Swapna. "Variation in condylar morphology in different malocclusion among Indians". Bioinformation 17, n. 12 (31 dicembre 2022): 1134–37. http://dx.doi.org/10.6026/973206300171134.
Testo completoAbstract (sommario):
Temporo-mandibular joint (TMJ) joint and the condyle of mandible are observed in the radiographs of the skull and the jaw. Therefore, it is of interest to assess the predictability of four different shapes of condyle in skeletal class I, II and III malocclusion. The four commonly visualized shapes are oval, bird beak, diamond and crooked were assessed using an ortho pantomogram (OPG). Each of the malocclusion was visualized for different shapes of the condyle. 987 OPGs were radiographically evaluated and the morphology of 1974 condylar heads was visualized. The shapes of the condyles were grouped under four different types. Data shows that oval shaped condyle was most common followed by bird beak. There was variability in the diamond and crooked shape and was lesser than the other types. Thus, the shapes of the condyle are useful predictable guide in deciding the nature of the occlusion.
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Yu, Siyu, Lindred L. Greer, Nir Halevy e Lisanne van Bunderen. "On Ladders and Pyramids: Hierarchy’s Shape Determines Relationships and Performance in Groups". Personality and Social Psychology Bulletin 45, n. 12 (22 aprile 2019): 1717–33. http://dx.doi.org/10.1177/0146167219842867.
Testo completoAbstract (sommario):
Hierarchies take different forms, which individuals mentally represent using different geometric shapes. We propose and empirically demonstrate that individuals’ mental representations of the shape hierarchy takes affect its consequences. Five studies compared two common mental representations of hierarchy shapes—ladders and pyramids—to explore whether, why, and how individuals’ perceptions of hierarchy’s shape undermine constructive relationships within groups and group performance. Study 1 demonstrated that individuals commonly mentally represent hierarchies as ladders and pyramids. In Studies 2 and 3, employees who perceived their workplace hierarchies to be shaped like ladders (as compared with pyramids) experienced worse intragroup relationships. Finally, Studies 4 and 5 experimentally manipulated groups’ hierarchical shape in the lab and found that ladder-shaped hierarchies undermined social relationships and group performance relative to pyramid-shaped hierarchies. Taken together, these findings enhance our understanding of hierarchies’ multifaceted consequences and help shed light on the (dis)utility of hierarchy for group functioning.
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Berrini, Elisa, Bernard Mourrain, Yann Roux, Mathieu Durand e Guillaume Fontaine. "Geometric Modelling and Deformation for Shape Optimization of Ship Hulls and Appendages". Journal of Ship Research 61, n. 02 (1 giugno 2017): 91–106. http://dx.doi.org/10.5957/jsr.2017.61.2.91.
Testo completoAbstract (sommario):
The precise control of geometric models plays an important role in many domains such as computer-aided geometric design and numerical simulation. For shape optimization in computational fluid dynamics (CFD), the choice of control parameters and the way to deform a shape are critical. In this article, we describe a skeleton-based representation of shapes adapted for CFD simulation and automatic shape optimization. Instead of using the control points of a classic B-spline representation, we control the geometry in terms of architectural parameters. We assure valid shapes with a strong shape consistency control. Deformations of the geometry are performed by solving optimization problems on the skeleton. Finally, a surface reconstruction method is proposed to evaluate the shape's performances with CFD solvers. We illustrate the approach on two problems: the foil of an AC45 racing sail boat and the bulbous bow of a fishing trawler. For each case, we obtained a set of shape deformations and then we evaluated and analyzed the performances of the different shapes with CFD computations.
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Andiyan, Andiyan, e Wima Alkad Albadira. "Study of Building Mass Forms in Jardin Cihampelas Apartment". MARKA (Media Arsitektur dan Kota) : Jurnal Ilmiah Penelitian 5, n. 1 (26 agosto 2021): 15–26. http://dx.doi.org/10.33510/marka.2021.5.1.15-26.
Testo completoAbstract (sommario):
Cihampelas Street Bandung is one of the main tourist destinations in Bandung; besides that, Cihampelas is also a residential area with a high population density. Jalan Cihampelas has many residential places, one of which is the Jardin Cihampelas Apartment. The Jardin Cihampelas Apartment is a building consisting of 4 building towers, namely towers A, B, C, and D. Each tower has 23 floors, and a U shape, Tower A - B and C - D are located close to each other on the inside of the "U" shaped mass surrounding the swimming pool. The approach used is geometry, and basic shapes, geometry, and basic shapes show that architecture is an expression of humans and is a basic principle always present from a work of architecture. This research aims to study the relationship between geometric shapes that affect the Jardin Cihampelas apartment building mass. The method used is a descriptive qualitative method using field surveys; the research study is the shape of the building mass in geometric shapes. The research variables discussed include basic form, unity, proportion, balance, rhythm, and emphasis. This research is expected to get useful results from studying the mass shape of the building in the Jardin Cihampelas apartment with the residential typology of tall buildings with geometric shapes in the processing of space in structures.
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Afzal, Ali, Omar Harzallah, Jean-Yves Drean, Niaz-Ahmad Akhtar e Sheraz Ahmad. "Performance characterization of multifunctional different cross-sectional-shaped coaxial composite filaments for SMART textile applications". Journal of Industrial Textiles 48, n. 6 (6 febbraio 2018): 1059–80. http://dx.doi.org/10.1177/1528083718757522.
Testo completoAbstract (sommario):
The aim of this study is to investigate the effect of spinneret design parameters on cross-sectional shape and mechanical performance characteristics of coaxial composite filaments. A number of different cross-sectional-shaped metal/polymer core/sheath coaxial composite filaments were developed by changing spinneret design parameters. The cross-sectional shapes obtained were circular, rectangular, triangular and elliptical shapes. The mechanical performance of filaments was evaluated for application in sensors and actuators. The change of cross-sectional shape significantly influences mechanical properties of developed filaments which express their vulnerability during applied stresses in their life cycle.
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Zhang, Huan, Srutha Venkatesan e Beiyan Nan. "Myxococcus xanthus as a Model Organism for Peptidoglycan Assembly and Bacterial Morphogenesis". Microorganisms 9, n. 5 (24 aprile 2021): 916. http://dx.doi.org/10.3390/microorganisms9050916.
Testo completoAbstract (sommario):
A fundamental question in biology is how cell shapes are genetically encoded and enzymatically generated. Prevalent shapes among walled bacteria include spheres and rods. These shapes are chiefly determined by the peptidoglycan (PG) cell wall. Bacterial division results in two daughter cells, whose shapes are predetermined by the mother. This makes it difficult to explore the origin of cell shapes in healthy bacteria. In this review, we argue that the Gram-negative bacterium Myxococcus xanthus is an ideal model for understanding PG assembly and bacterial morphogenesis, because it forms rods and spheres at different life stages. Rod-shaped vegetative cells of M. xanthus can thoroughly degrade their PG and form spherical spores. As these spores germinate, cells rebuild their PG and reestablish rod shape without preexisting templates. Such a unique sphere-to-rod transition provides a rare opportunity to visualize de novo PG assembly and rod-like morphogenesis in a well-established model organism.
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Kumar, Pramod, Santanu Dwari, Shailendra Singh, Ashok Kumar, N. K. Agrawal e Utkarsh Kumar. "Analysis and Optimization of Conformal Patch Excited Wideband DRA of Several Shapes". Frequenz 72, n. 5-6 (25 aprile 2018): 197–208. http://dx.doi.org/10.1515/freq-2017-0039.
Testo completoAbstract (sommario):
AbstractIn this paper various shapes of DR antennas excited by common feed have been proposed and successfully implemented for wideband applications. Proposed structures are Hemispherical, Arrow-shaped and Triangular DRA, while common excited feed is inverted trapezoidal conformal patch. These shapes of DR offer significant optimization in several parameters such as impedance bandwidth, peak gain and bandwidth per unit volume of the antenna. By using inverted trapezoidal patch feed mechanism an impedance bandwidth (VSWR<2) of about 63 % for hemispherical shape, 66 % for arrow shape, and 72 % for triangular shape DRA has been achieved with maximum bandwidth per unit volume. Proposed wideband DRAs i. e. triangular, hemispherical, and arrow shapes of DR antennas cover almost complete C-band (4 GHz–8 GHz) frequency spectrum of microwave. The average peak gain within the operating band for hemispherical, arrow, and triangular shape DRA are about 5, 5.4, and 5.5 dB respectively. A comparative analysis of proposed structures for various antenna parameters has been analyzed by HFSS (High-Frequency Structure Simulator) and validated by experimental results.
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Jayadevan, Vijai, Tadamasa Sawada, Edward Delp e Zygmunt Pizlo. "Perception of 3D Symmetrical and Nearly Symmetrical Shapes". Symmetry 10, n. 8 (16 agosto 2018): 344. http://dx.doi.org/10.3390/sym10080344.
Testo completoAbstract (sommario):
The human visual system uses priors to convert an ill-posed inverse problem of 3D shape recovery into a well-posed one. In previous studies, we have demonstrated the use of priors like symmetry, compactness and minimal surface in the perception of 3D symmetric shapes. We also showed that binocular perception of symmetric shapes can be well modeled by the above-mentioned priors and binocular depth order information. In this study, which used a shape-matching task, we show that these priors can also be used to model perception of near-symmetrical shapes. Our near-symmetrical shapes are asymmetrical shapes obtained from affine distortions of symmetrical shapes. We found that the perception of symmetrical shapes is closer to veridical than the perception of asymmetrical shapes is. We introduce a metric to measure asymmetry of abstract polyhedral shapes, and a similar metric to measure shape dissimilarity between two polyhedral shapes. We report some key observations obtained by analyzing the data from the experiment. A website was developed with all the shapes used in the experiment, along with the shapes recovered by the subject and the shapes recovered by the model. This website provides a qualitative analysis of the effectiveness of the model and also helps demonstrate the goodness of the shape metric.
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Fang, Weixiang, Kailing Yu, Songhan Zhang, Lai Jiang, Hongyue Zheng, Qiaoling Huang e Fanzhu Li. "Shape Matters: Impact of Mesoporous Silica Nanoparticle Morphology on Anti-Tumor Efficacy". Pharmaceutics 16, n. 5 (8 maggio 2024): 632. http://dx.doi.org/10.3390/pharmaceutics16050632.
Testo completoAbstract (sommario):
A nanoparticle’s shape is a critical determinant of its biological interactions and therapeutic effectiveness. This study investigates the influence of shape on the performance of mesoporous silica nanoparticles (MSNs) in anticancer therapy. MSNs with spherical, rod-like, and hexagonal-plate-like shapes were synthesized, with particle sizes of around 240 nm, and their other surface properties were characterized. The drug loading capacities of the three shapes were controlled to be 47.46%, 49.41%, and 46.65%, respectively. The effects of shape on the release behaviors, cellular uptake mechanisms, and pharmacological behaviors of MSNs were systematically investigated. Through a series of in vitro studies using 4T1 cells and in vivo evaluations in 4T1 tumor-bearing mice, the release kinetics, cellular behaviors, pharmacological effects, circulation profiles, and therapeutic efficacy of MSNs were comprehensively assessed. Notably, hexagonal-plate-shaped MSNs loaded with PTX exhibited a prolonged circulation time (t1/2 = 13.59 ± 0.96 h), which was approximately 1.3 times that of spherical MSNs (t1/2 = 10.16 ± 0.38 h) and 1.5 times that of rod-shaped MSNs (t1/2 = 8.76 ± 1.37 h). This research underscores the significance of nanoparticles’ shapes in dictating their biological interactions and therapeutic outcomes, providing valuable insights for the rational design of targeted drug delivery systems in cancer therapy.
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Zhou, Yadong, e Qingguo Fei. "Evaluation of opening-hole shapes for rivet connection of a composite plate". Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 231, n. 20 (22 maggio 2016): 3810–17. http://dx.doi.org/10.1177/0954406216652169.
Testo completoAbstract (sommario):
The rivet joint is an important mechanical connection for hot structures made of ceramic matrix composites. The development of chemical vapor infiltration technology provides a possible application of novel rivets for these structural components. However, connectors can still be the weakest link for structural integrity due to the severe stress concentration around the rivet joint holes. The geometry parameters of the rivet hole can be key influencing factors to the structural strength. A comparative evaluation is presented to analyze the influence of opening-hole shapes on the structural stress concentration of a composite plate. The opening-hole shapes considered include circle, ellipse, and racetrack. The finite element (FE) models of specimens with the three shapes of rivet holes were constructed. The stress distributions of the specimens under tensile loading were analyzed to compare the stress concentration factor (SCF) of different opening-hole shapes. An optimal shape, i.e. racetrack-shaped, was determined based on the SCF reduction of specimen-level comparison. Then, FE models of a composite plate containing rivet holes were built to verify the outperformance of the racetrack-shaped hole. A stress concentration reduction of the plate with racetrack-shaped holes was observed compared to the one with circular holes.
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Kamangar, Sarfaraz, Govindaraju Kalimuthu, Irfan Anjum Badruddin, A. Badarudin, N. J. Salman Ahmed e T. M. Yunus Khan. "Numerical Investigation of the Effect of Stenosis Geometry on the Coronary Diagnostic Parameters". Scientific World Journal 2014 (2014): 1–7. http://dx.doi.org/10.1155/2014/354946.
Testo completoAbstract (sommario):
The present study deals with the functional severity of a coronary artery stenosis assessed by the fractional flow reserve (FFR). The effects of different geometrical shapes of lesion on the diagnostic parameters are unknown. In this study, 3D computational simulation of blood flow in three different geometrical shapes of stenosis (triangular, elliptical, and trapezium) is considered in steady and transient conditions for 70% (moderate), 80% (intermediate), and 90% (severe) area stenosis (AS). For a given percentage AS, the variation of diagnostic parameters which are derived from pressure drop across the stenosis was found in three different geometrical shapes of stenosis and it was observed that FFR is higher in triangular shape and lower in trapezium shape. The pressure drop coefficient (CDP) was higher in trapezium shape and lower in triangular model whereas the LFC shows opposite trend. From the clinical perspective, the relationship between percentage AS and FFR is linear and inversely related in all the three models. A cut-off value of 0.75 for FFR was observed at 76.5% AS in trapezium model, 79.5% in elliptical model, and 82.7% AS for the triangular shaped model. The misinterpretation of the functional severity of the stenosis is in the region of 76.5%-82.7 % AS from different shapes of stenosis models.
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Kiliani, J., G. Baumgarten, F. J. Lübken e U. Berger. "Impact of particle shape on the morphology of noctilucent clouds". Atmospheric Chemistry and Physics 15, n. 22 (19 novembre 2015): 12897–907. http://dx.doi.org/10.5194/acp-15-12897-2015.
Testo completoAbstract (sommario):
Abstract. Noctilucent clouds (NLCs) occur during summer in the polar region at altitudes around 83 km. They consist of ice particles with a typical size around 50 nm. The shape of NLC particles is less well known but is important both for interpreting optical measurements and modeling ice cloud characteristics. In this paper, NLC modeling of microphysics and optics is adapted to use cylindrical instead of spherical particle shape. The optical properties of the resulting ice clouds are compared directly to NLC three-color measurements by the Arctic Lidar Observatory for Middle Atmosphere Research (ALOMAR) Rayleigh/Mie/Raman (RMR) lidar between 1998 and 2014. Shape distributions including both needle- and disc-shaped particles are consistent with lidar measurements. The best agreement occurs if disc shapes are 60 % more common than needles, with a mean axis ratio of 2.8. Cylindrical particles cause stronger ice clouds on average than spherical shapes with an increase of backscatter at 532 nm by &approx; 30 % and about 20 % in ice mass density. This difference is less pronounced for bright than for weak ice clouds. Cylindrical shapes also cause NLCs to have larger but a smaller number of ice particles than for spherical shapes.
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Rosen, Jeffrey J. "Shapes That Shape the Shape of Brain and Society". Contemporary Psychology: A Journal of Reviews 35, n. 2 (febbraio 1990): 138–39. http://dx.doi.org/10.1037/028258.
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Wiegers, Tjamme, Lau Langeveld e Joris Vergeest. "Shape language: How people describe shapes and shape operations". Design Studies 32, n. 4 (luglio 2011): 333–47. http://dx.doi.org/10.1016/j.destud.2011.03.002.
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Li, Ying, Yongfeng Li e Tianxing Wang. "The Size and Shape Dependence of Ferromagnetism in Nanomagnets". Journal of Nanomaterials 2012 (2012): 1–6. http://dx.doi.org/10.1155/2012/897203.
Testo completoAbstract (sommario):
The size and shape dependence of dynamic behaviors of nanomagnets is studied by the kinetic Monte Carlo method based on the transition state theory. We analyze the hysteresis curves of the nanomagnet systems with different shapes (or spin array patterns) in the presence of an external magnetic field. The results show that the magnetization of the chain-shaped nanomagnet is more sensitive to the applied field than that of the oblong-shaped or bulk-shaped systems. For the same magnetic nanostructure, the coercive field presents an exponential decay with temperature. Moreover, the coercive field is found to be strongly dependent on the effective coordination number, which has different values corresponding to those systems of different size and shapes (spin array patterns).
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Haider, Sajjad, Adnan Saeed Butt, Imran Syed Muhammad, Asif Ali, Yun-Zhang Li, Syed Muhammad Ali Naqvi e Muhammad Adnan Qaiser. "Impact of nano-particles shapes on Al2O3-water nano-fluid flow due to a stretching cylinder". International Journal of Numerical Methods for Heat & Fluid Flow 30, n. 5 (19 agosto 2019): 2809–32. http://dx.doi.org/10.1108/hff-02-2019-0113.
Testo completoAbstract (sommario):
Purpose The purpose of this study is to theoretically probe the shape impacts of nano-particle on boundary layer flow of nano-fluid toward a stretching cylinder with heat-transmission effects. The base fluid used for this study is pure water, and aluminum oxide nano-particles are suspended in it. Four different shapes of nano-particle, namely, cylindrical, brick, platelets and blades, are considered to carry out the study. Design/methodology/approach The problem is modelled mathematically and the nonlinear system of equations is attained by using appropriate transmutations. The solution of transmuted equations is achieved by utilizing a shooting technique with Fourth-Fifth order Runge–Kutta Fehlberg scheme. Numerically attained results are elucidated through graphs and tables which are further compared under limiting cases with existing literature to check the validity of the results. Findings It is observed that fluid velocity and temperature of cylindrical shaped water nano-fluids are more than the nano-fluid having brick-shaped nano-particles. Moreover, it is seen that the nano-fluids suspended with platelets-shaped nano-particles have higher velocity and temperature than the nano-fluids containing blade-shaped nano-particles. The curvature parameter and nano-particles volume fraction have increasing effects on flow velocity and temperature of nano-fluids containing all types of nano-particle shapes. Originality/value Numerous authors have examined the impacts of nano-particle shapes on characteristics of heat transfer and fluid flow. However, to the best of the authors’ knowledge, the shape impacts of nano-particles on boundary layer flow of nano-fluid toward a stretching cylinder with heat-transmission effects have not been discussed. So, to fulfill this gap, the present paper explicates the impacts of various nano-particle shapes on Al2O3–water-based nano-fluid flow past a stretching cylinder with heat-transfer effects.
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Jayaraj K, Aiswarya, e Anila S. "Shape Optimisation of Grooves in Grooved Gusset Plate Damper used in X-Braced Frame". Journal of Structural Technology 9, n. 2 (22 maggio 2024): 1–7. http://dx.doi.org/10.46610/jost.2024.v09i02.001.
Testo completoAbstract (sommario):
The X-braced frame represents a specialized variation of concentric-braced frames. It can be used as a resistance towards the lateral load acting on the structural system. X-braced frames generally exhibit lower flexibility when compared to eccentrically braced and moment frames, which is often perceived as a drawback of this structural system. To address this limitation, energy dissipation devices can be integrated into the system with X-bracings to absorb the plastic action and safeguard other structural elements, such as columns, beams and connections from earthquake forces. Specifically, X-concentrically braced frames are tailored through variations in groove shapes. Furthermore, the investigation determines the dampers' load-bearing and energy dissipation capacities. The assessment commences with cyclic load testing conducted using the ANSYS software. The grooves present in GGPD help dissipate seismic energy. The energy dissipation and load-bearing capacity of the X-concentrically braced frame equipped with a grooved gusset plate damper were compared based on different groove shapes. The different shapes used for the analysis were L shape, oval, rectangular and stadium shape. It was observed that oval-shaped grooves have more energy dissipation capacity among four groove shapes, with an increase of 10.74%.