Comparison of the Cross Sectional Area, the Loss in Volume and the Mechanical Properties of LAE442 and MgCa0.8 as Resorbable Magnesium Alloy Implants after 12 Months Implantation Duration

Current research focuses on magnesium based alloys in the course of searching a resorbable osteosynthetic material which provides sufficient mechanical properties besides a good biocompatibility. Previous studies reported on a favorable biocompatibility of the alloys LAE442 and MgCa0.8. The present study compared the degradation process of cylindrical LAE442 and MgCa0.8 implants after 12 months implantation duration. Therefore, 10 extruded implants (2.5 x 25 mm, cross sectional area 4.9 mm²) of both alloys were implanted into the medullary cavity of both tibiae of rabbits for 12 months. After euthanization, the right bone-implant-compound was scanned in a µ-computed tomograph (µCT80, ScancoMedical) and nine uniformly distributed cross-sections of each implant were used to determine the residual implants´ cross sectional area (Software AxioVisionRelease 4.5, Zeiss). Left implants were taken out of the bone carefully. After weighing, a three-point bending test was carried out. LAE442 implants degraded obviously slower and more homogeneously than MgCa0.8. The mean residual cross sectional area of LAE442 implants was 4.7 ± 0.07 mm². MgCa0.8 showed an area of only 2.18 ± 1.03 mm². In contrast, the loss in volume of LAE442 pins was more obvious. They lost 64 % of their initial weight. The volume of MgCa0.8 reduced clearly to 54.4 % which corresponds to the cross sectional area results. Three point bending tests revealed that LAE442 showed a loss in strength of 71.2 % while MgCa0.8 lost 85.6 % of its initial strength. All results indicated that LAE442 implants degraded slowly, probably due to the formation of a very obvious degradation layer. Degradation of MgCa0.8 implants was far advanced.

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Effects of cross-sessional area and aspect ratio coupled with orientation on mechanical properties and deformation behavior of Cu nanowires

Nanotechnology ◽

10.1088/1361-6528/ac3e32 ◽

2021 ◽

Author(s):

Hui Cao ◽

Wenke Chen ◽

Zhiyuan Rui ◽

Changfeng Yan

Keyword(s):

Mechanical Properties ◽

Aspect Ratio ◽

Yield Stress ◽

Young’S Modulus ◽

Young's Modulus ◽

Cross Sectional Area ◽

Sectional Area ◽

Cross Sectional ◽

Cu Nanowires ◽

The Cross

Abstract Metal nanomaterials exhibit excellent mechanical properties compared with corresponding bulk materials and have potential applications in various areas. Despite a number of studies of the size effect on Cu nanowires mechanical properties with square cross-sectional, investigations of them in rectangular cross-sectional with various sizes at constant volume are rare, and lack of multifactor coupling effect on mechanical properties and quantitative investigation. In this work, the dependence of mechanical properties and deformation mechanisms of Cu nanowires/nanoplates under tension on cross-sessional area, aspect ratio of cross-sectional coupled with orientation were investigated using molecular dynamics simulations and the semi-empirical expressions related to mechanical properties were proposed. The simulation results show that the Young’s modulus and the yield stress sharply increase with the aspect ratio except for the <110>{110}{001} Cu nanowires/nanoplates at the same cross-sectional area. And the Young’s modulus increases while the yield stress decreases with the cross-sectional area of Cu nanowires. However, both of them increase with the cross-sectional area of Cu nanoplates. Besides, the Young’s modulus increases with the cross-sectional area at all the orientations. The yield stress shows a mildly downward trend except for the <111> Cu nanowires with increased cross-sectional area. For the Cu nanowires with a small cross-sectional area, the surface force increases with the aspect ratio. In contrast, it decreases with the aspect ratio increase at a large cross-sectional area. At the cross-sectional area of 13.068 nm2, the surface force decreases with the aspect ratio of the <110> Cu nanowires while it increases at other orientations. The surface force is a linearly decreasing function of the cross-sectional area at different orientations. Quantitative studies show that Young’s modulus and yield stress to the aspect ratio of the Cu nanowires satisfy exponent relationship. In addition, the main deformation mechanism of Cu nanowires is the nucleation and propagation of partial dislocations while it is the twinning-dominated reorientation for Cu nanoplates.

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Providing the spatial rigidity of a multi-story wood-based frame building

Herald of Dagestan State Technical University Technical Sciences ◽

10.21822/2073-6185-2020-47-4-151-161 ◽

2021 ◽

Vol 47 (4) ◽

pp. 151-161

Author(s):

A. F. Rozhkov ◽

A. A. Lavrov ◽

I. V. Pikuleva ◽

D. A. Polivanov

Keyword(s):

Cross Sections ◽

Cross Sectional Area ◽

Sectional Area ◽

Labor Costs ◽

Preliminary Calculation ◽

Cross Sectional ◽

Frame Building ◽

The Cross ◽

Internal Volume ◽

Office Software

Objective. The article deals with the problem of ensuring the rigidity of a frame wooden multi-story building and ways to achieve the necessary spatial rigidity, taking into account the requirements of preserving the internal volume and free space. The case of excess spatial rigidity and measures to optimize it are provided to increase the economic efficiency of the project.Methods. A simpler and less time-consuming method is the initial estimation of the cross-sectional area of the rigid elements that take the wind load. The authors propose a method for the preliminary calculation of building stiffness with subsequent adjustment in the calculation scheme.Results. The design scheme of the building frame is made in the Scad Office software package to take into account the influence of the own structure weight, the redistribution of forces and movements due to the spatial work of the frame, with subsequent adjustment of the cross-sections of rigid elements.Conclusion. The most rational and least time-consuming method for numerical calculation of stiffness is the initial estimation of the cross-sectional area of the system of rigid elements. With its help, it is possible to avoid an excess of spatial rigidity of the building and reduce the time and labor costs for selecting the location of rigid elements.

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The emission of internal waves by vibrating cylinders

Journal of Fluid Mechanics ◽

10.1017/s0022112069001911 ◽

1969 ◽

Vol 36 (4) ◽

pp. 657-672 ◽

Cited By ~ 15

Author(s):

D. G. Hurley

Keyword(s):

Internal Waves ◽

Cross Sections ◽

Power Output ◽

Simple Expression ◽

Cross Sectional Area ◽

Rate Of Change ◽

Body Of Revolution ◽

Sectional Area ◽

Cross Sectional ◽

The Cross

The paper describes an investigation of the internal waves that are produced in a stratified fluid having constant Brunt—Väisälä frequency by a cylinder which executes small vibrations at a lower frequency. Explicit solutions are found for slender cylinders having arbitrary cross-sections. When the cross-sectional area of the cylinder varies with time it is found necessary in calculating the surface pressures and power output to take account of terms in the governing equations that are significant only at distances from the cylinder comparable to or larger than the scale height of the density variations. For this case a simple expression for the power output is obtained in terms of the rate of change of the cross-sectional area of the cylinder.When the vibrating cylinder is rigid its cross-sectional area is independent of time and then the expression for the power output is very similar to von Kármán's expression for the drag of a body of revolution in supersonic flow.In both the above cases it is found that one quarter of the power is radiated in each of the four directions that are inclined at a particular angle to the horizontal.

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CALCULATION OF NON-STANDARD SINGLE CARGO HOOK

ВЕСТНИК ВОРОНЕЖСКОГО ГОСУДАРСТВЕННОГО ТЕХНИЧЕСКОГО УНИВЕРСИТЕТА ◽

10.36622/vstu.2021.17.4.021 ◽

2021 ◽

pp. 148-155

Author(s):

В.И. Сероштан ◽

П.В. Витчук ◽

В.Ю. Анцев ◽

Н.А. Витчук

Keyword(s):

Cross Sections ◽

Hot Stamping ◽

Cross Sectional Area ◽

Design Stage ◽

Sectional Area ◽

Current Standard ◽

Cross Sectional ◽

The Cross ◽

The Difference ◽

Positive Effect

Oднорогие грузовые крюки грузоподъемных кранов изготавливают способом горячей штамповки и свободной ковки. Действующим стандартом предусмотрено 26 типоразмеров заготовок грузовых крюков. Очевидно, что номенклатура стандартных однорогих грузовых крюков ограничена и не может удовлетворить всего многообразия требований при создании специальных грузоподъемных машин для конкретных условий. В случае применения нестандартных крюков или при нестандартной грузоподъемности крана проводится поверочный расчет крюка. В существующем упрощенном методе расчета однорогих грузовых крюков сечения крюка заменяют правильной трапецией без учета скруглений. Поэтому предложен уточненный метод расчета нестандартных однорогих крюков грузоподъемных кранов. Осуществлена проверка предлагаемого метода при помощи SolidWorks, доказана его точность. Проведен сравнительный анализ результатов вычислений по предлагаемому и существующему упрощенному методам. Сравнение расчетных площадей сечений грузовых крюков, полученных предлагаемым и упрощенным методами, показывает, что разница между ними для стандартных крюков колеблется в пределах 6-10%. В среднем площадь сечения крюка, полученная по предлагаемому уточненному расчету, меньше, чем по упрощенному на 8%. Результаты расчета точной площади поперечного сечения грузового крюка и полученные на их основе значения напряжений в опасных сечениях позволяют на стадии проектирования достичь оптимальной формы грузового крюка. Это позволит в процессе производства получить наименьшее значение металлоемкости грузового крюка, что положительно скажется на его себестоимости Load single-hooks for cranes are made by hot stamping and free forging. The current standard provides for 26 standard sizes of cargo hook blanks. Obviously, the range of standard single-horned cargo hooks is limited and cannot satisfy the whole variety of requirements when creating special lifting machines for specific conditions. In the case of using non-standard hooks or with non-standard crane lifting capacity, a verification calculation of the hook is carried out. In the existing simplified method for calculating one-horned load hooks, the cross-sections of the hook are replaced with a regular trapezoid without taking into account the fillets. Therefore, we propose a refined method for calculating non-standard single-horned hooks of hoisting cranes. We tested the method using SolidWorks and proved its accuracy. We carried out a comparative analysis of the results of calculations by the proposed and existing simplified methods. Comparison of the calculated cross-sectional areas of cargo hooks obtained by the proposed and simplified methods shows that the difference between them for standard hooks ranges from 6-10%. On average, the cross-sectional area ofthe hook, obtained according to the proposed refined calculation, is less than the simplified one by 8%. The results of calculating the exact cross-sectional area of the load hook and the values of stresses in dangerous sections obtained on their basis allow one at the design stage to achieve the optimal shape of the load hook. This will allow one in the production process to obtain the smallest value of the metal consumption of the cargo hook, which will have a positive effect on its cost

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Steady analysis of transcritical flows in collapsible tubes with discontinuous mechanical properties: implications for arteries and veins

Journal of Fluid Mechanics ◽

10.1017/jfm.2013.542 ◽

2013 ◽

Vol 736 ◽

pp. 195-215 ◽

Cited By ~ 8

Author(s):

A. Siviglia ◽

M. Toffolon

Keyword(s):

Mechanical Properties ◽

Free Surface Flows ◽

Cross Sectional Area ◽

Sectional Area ◽

Collapsible Tube ◽

Cross Sectional ◽

Collapsible Tubes ◽

The Cross ◽

Transcritical Flows ◽

Arteries And Veins

AbstractWe study the conditions under which discontinuous mechanical properties of a collapsible tube can induce transcritical flows, i.e. the transition through the critical state where the speed index (analogous to the Mach or the Froude numbers for compressible and free surface flows, respectively) is one. Such a critical transition may strongly modify the flow properties, cause a significant reduction in the cross-sectional area of the tube, and limit the flow. General relationships are obtained for a short segment using a one-dimensional model under steady flow conditions. Marginal curves delimiting the transcritical regions are identified in terms of the speed index and the cross-sectional area ratio. Since there are many examples of such flows in physiology and medicine, we also analyse the specific case of prosthesis (graft or stent) implantation in blood vessels. We then compute transcritical conditions for the case of stiffness and reference area variations, considering a collapsible tube characterized by physiological parameters representative of both arteries and veins. The results suggest that variations in mechanical properties may induce transcritical flow in veins but is unrealistic in arteries.

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Tensile mechanical properties of human forearm tendons

Journal of Hand Surgery (European Volume) ◽

10.1177/1753193415584715 ◽

2015 ◽

Vol 40 (7) ◽

pp. 711-719 ◽

Cited By ~ 9

Author(s):

J. F. Weber ◽

A. M. R. Agur ◽

A. Y. Fattah ◽

K. D. Gordon ◽

M. L. Oliver

Keyword(s):

Mechanical Properties ◽

Biomechanical Properties ◽

Cross Sectional Area ◽

Sectional Area ◽

Visual Estimation ◽

Cross Sectional ◽

Laser Reflectance ◽

Human Forearm ◽

Fresh Frozen ◽

The Cross

Previous studies of the mechanical properties of tendons in the upper limb have used embalmed specimens or sub-optimal methods of measurement. The aim of this study was to determine the biomechanical properties of all tendons from five fresh frozen cadaveric forearms using updated methodology. The cross-sectional area of tendons was accurately measured using a laser reflectance system. Tensile testing was done in a precision servo-hydraulic device with cryo-clamp fixation. We determined that the cross-sectional area of some tendons is variable and directly influences the calculated material properties; visual estimation of this is unreliable. Data trends illustrate that digital extensor tendons possess the greatest tensile strength and a higher Young’s modulus than other tendon types.

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Biomechanical Studies of the Rabbit Patellar Tendon After Removal of Its One-Fourth or a Half

Journal of Biomechanical Engineering ◽

10.1115/1.2798328 ◽

1999 ◽

Vol 121 (3) ◽

pp. 323-329 ◽

Cited By ~ 12

Author(s):

N. Yamamoto ◽

K. Hayashi ◽

F. Hayashi ◽

K. Yasuda ◽

K. Kaneda

Keyword(s):

Mechanical Properties ◽

Patellar Tendon ◽

Rabbit Model ◽

Cross Sectional Area ◽

Sectional Area ◽

Cross Sectional ◽

Histological Studies ◽

The Cross ◽

The One ◽

Original Area

Effects of the overstressing induced by the harvest of grafts from the patellar tendon on the mechanical properties and morphometry of remaining tendon were studied using a rabbit model. The width of the patellar tendon was reduced by one-fourth or one-half equally removing the medial and lateral portions; by this surgery, the cross-sectional area was decreased by 25 or 50 percent from the original area. After all the rabbits were allowed unrestricted activities in cages for 3 to 12 weeks, their patellar tendons were harvested for mechanical and histological studies. The one-fourth removal induced no significant changes in the mechanical properties, but significantly increased the cross-sectional area. In the case of one-half removal, tensile strength and tangent modulus did not change in some tendons, although the cross-sectional area increased significantly. In the other central half tendons, mechanical strength decreased markedly, while the cross-sectional area increased; hypercellular areas and breakage of collagen bundles were observed in these tendons. These results indicate that the patellar tendon has an ability of functionally adapting to overstressing by changing the cross-sectional area, while keeping the mechanical properties unchanged, if the extent of overstressing is less than 30 percent.

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Atrophy patterns in isolated subscapularis lesions

BMC Musculoskeletal Disorders ◽

10.1186/s12891-021-04241-5 ◽

2021 ◽

Vol 22 (1) ◽

Author(s):

Gernot Seppel ◽

Andreas Voss ◽

Daniel J. H. Henderson ◽

Simone Waldt ◽

Bernhard Haller ◽

...

Keyword(s):

Muscle Atrophy ◽

Area Ratio ◽

Cross Sectional Area ◽

Control Group ◽

Sectional Area ◽

Cross Sectional ◽

Subscapularis Muscle ◽

Mri Scans ◽

The Mean ◽

The Cross

Abstract Background While supraspinatus atrophy can be described according to the system of Zanetti or Thomazeau there is still a lack of characterization of isolated subscapularis muscle atrophy. The aim of this study was to describe patterns of muscle atrophy following repair of isolated subscapularis (SSC) tendon. Methods Forty-nine control shoulder MRI scans, without rotator cuff pathology, atrophy or fatty infiltration, were prospectively evaluated and subscapularis diameters as well as cross sectional areas (complete and upper half) were assessed in a standardized oblique sagittal plane. Calculation of the ratio between the upper half of the cross sectional area (CSA) and the total CSA was performed. Eleven MRI scans of patients with subscapularis atrophy following isolated subscapularis tendon tears were analysed and cross sectional area ratio (upper half /total) determined. To guarantee reliable measurement of the CSA and its ratio, bony landmarks were also defined. All parameters were statistically compared for inter-rater reliability, reproducibility and capacity to quantify subscapularis atrophy. Results The mean age in the control group was 49.7 years (± 15.0). The mean cross sectional area (CSA) was 2367.0 mm2 (± 741.4) for the complete subscapularis muscle and 1048.2 mm2 (± 313.3) for the upper half, giving a mean ratio of 0.446 (± 0.046). In the subscapularis repair group the mean age was 56.7 years (± 9.3). With a mean cross sectional area of 1554.7 mm2 (± 419.9) for the complete and of 422.9 mm2 (± 173.6) for the upper half of the subscapularis muscle, giving a mean CSA ratio of 0.269 (± 0.065) which was seen to be significantly lower than that of the control group (p < 0.05). Conclusion Analysis of typical atrophy patterns of the subscapularis muscle demonstrates that the CSA ratio represents a reliable and reproducible assessment tool in quantifying subscapularis atrophy. We propose the classification of subscapularis atrophy as Stage I (mild atrophy) in case of reduction of the cross sectional area ratio < 0.4, Stage II (moderate atrophy) in case of < 0.35 and Stage III (severe atrophy) if < 0.3.

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The area of eye muscle of beef cattle carcasses

Australian Journal of Experimental Agriculture ◽

10.1071/ea9630249 ◽

1963 ◽

Vol 3 (10) ◽

pp. 249

Author(s):

RM Seebeck

Keyword(s):

Beef Cattle ◽

Cross Sectional Area ◽

Carcass Weight ◽

Sectional Area ◽

Muscle Area ◽

Cross Sectional ◽

Eye Muscle ◽

Angus Cattle ◽

The Cross

Variations in the cross-sectional area of eye muscle of carcasses cut between the tenth and eleventh ribs were investigated, using 105 Hereford and 51 Angus steers aged 20 months. These cattle consisted of three groups, born in successive years. At constant carcass weight, statistically significant differences in eye muscle area were found between breeds and between years. Breed and year differences were also found in eye muscle area with width and depth of eye muscle constant, so that there are limitations to the estimation of eye muscle area from width and depth measurements. A nomograph is given for estimating eye muscle area from width and depth for Hereford and Angus cattle, when all animals are reared in the same year and environment. The use of eye muscle area as an indicator of weight of carcass muscle is discussed.

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