scholarly journals Numerical Analysis and Experiment for Stress Wave Propagation in Two Connected Cylindrical Bodies with Different Cross-Sectional Area and Same Mechanical Impedance

2018 ◽  
Vol 183 ◽  
pp. 01033
Author(s):  
Hidetoshi Kobayashi ◽  
Yuya Seo ◽  
Kinya Ogawa ◽  
Keitaro Horikawa ◽  
Ken-ichi Tanigaki
Keyword(s):  
Stress Wave ◽  
Incident Wave ◽  
Mechanical Impedance ◽  
Local Deformation ◽  
Cross Sectional Area ◽  
Stress Wave Propagation ◽  
Sectional Area ◽  
Cross Sectional ◽  
Reflected Waves ◽  
And Control

In this study, the behaviour of elastic stress wave propagating two connected cylindrical bodies was examined using dynamic finite element method (FEM). They consist of two bodies with different cross-sectional area, different Young’s modulus and identical mechanical impedance. It was found that when an incident wave passes through the boundary step between two different cross-sectional areas, a pair of reflected waves which has the same amplitude and opposite sign was observed, despite the same mechanical impedance. This phenomenon appears to be caused by the loading and unloading the boundary section due to the arrival and the passage of incident wave. It was also found that a connection manner to insert the smaller diameter cylinder into the other cylinder with a little length is quite effective for the reduction of the reflected wave, because of the superposition of waves from two edges and control of local deformation. This phenomenon was verified by a series of impact experiments using two cylindrical bodies connected by interference fit.

A three-microphone acoustic reflection technique using transmitted acoustic waves in the airway

2013 ◽  
Vol 115 (8) ◽  
pp. 1119-1125 ◽  
Author(s):  
Yuki Fujimoto ◽  
Jyongsu Huang ◽  
Toshiharu Fukunaga ◽  
Ryo Kato ◽  
Mari Higashino ◽  
...  
Keyword(s):  
Acoustic Waves ◽  
Cross Sectional Area ◽  
Distance Functions ◽  
Sectional Area ◽  
Wave Tube ◽  
Cross Sectional ◽  
Reflected Waves ◽  
Acoustic Reflection ◽  
Obstructive Sleep ◽  
And Function

The acoustic reflection technique noninvasively measures airway cross-sectional area vs. distance functions and uses a wave tube with a constant cross-sectional area to separate incidental and reflected waves introduced into the mouth or nostril. The accuracy of estimated cross-sectional areas gets worse in the deeper distances due to the nature of marching algorithms, i.e., errors of the estimated areas in the closer distances accumulate to those in the further distances. Here we present a new technique of acoustic reflection from measuring transmitted acoustic waves in the airway with three microphones and without employing a wave tube. Using miniaturized microphones mounted on a catheter, we estimated reflection coefficients among the microphones and separated incidental and reflected waves. A model study showed that the estimated cross-sectional area vs. distance function was coincident with the conventional two-microphone method, and it did not change with altered cross-sectional areas at the microphone position, although the estimated cross-sectional areas are relative values to that at the microphone position. The pharyngeal cross-sectional areas including retropalatal and retroglossal regions and the closing site during sleep was visualized in patients with obstructive sleep apnea. The method can be applicable to larger or smaller bronchi to evaluate the airspace and function in these localized airways.

scholarly journals A coupling model based on grey relational analysis and stepwise discriminant analysis for wood defect area identification by stress wave

BioResources ◽  
2020 ◽  
Vol 15 (1) ◽  
pp. 1171-1186
Author(s):  
Xin Li ◽  
Wei Qian ◽  
Liting Cheng ◽  
Lihong Chang
Keyword(s):  
Wave Propagation ◽  
Stress Wave ◽  
Propagation Velocity ◽  
Wood Specimen ◽  
Coupling Model ◽  
Stress Wave Propagation ◽  
Sectional Area ◽  
Wave Propagation Velocity ◽  
Cross Sectional ◽  
Stress Wave Propagation Velocity

Based on the experimental idea of reverse simulation, a quantitative area of hole was excavated at the sectional center of a wood specimen. The excavation area was 1/32S, 1/16S, 1/8S, 1/4S, and 1/2S (where S represents cross-sectional area of the complete specimen) and stress wave nondestructive testing of six sensors was performed. The stress wave propagation paths were statistically summarized to obtain the stress wave propagation velocity (Va) for two adjacent sensors, the stress wave propagation velocity (Vb) for two separated sensors, and the stress wave propagation velocity (Vc) for two opposite sensors. Furthermore, by analyzing the advantages and disadvantages of grey relation and stepwise discriminant model when both of them were used alone, a coupling model generated from them was established to dispose the test data. The attenuation ratios Ψa, Ψb, and Ψc of stress wave under three propagation paths and their relation ratios Va/Vb, Vb/Vc, and Va/Vc, a total of six groups of measured data, were selected as discriminant factors for the hole area grade of the wood specimen. The verification results showed that the discriminant accuracy of the coupling model was 100%, and it was concluded that the attenuation ratio (Ψb) of the stress wave propagation velocity for two separated sensors had the strongest discriminant ability against cross-sectional area of the specimen.

Relevance of classification by size to topographical differences in bronchial smooth muscle response

1993 ◽  
Vol 75 (5) ◽  
pp. 2013-2021 ◽  
Author(s):  
P. Chitano ◽  
S. B. Sigurdsson ◽  
A. J. Halayko ◽  
N. L. Stephens
Keyword(s):  
Smooth Muscle ◽  
Electrical Field Stimulation ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Muscle Response ◽  
Bronchial Responsiveness ◽  
Sixth Generation ◽  
Significant Difference ◽  
And Control

To investigate heterogeneity of airway smooth muscle response, we studied strips of large and small branches from third- to sixth-generation bronchi obtained from ragweed antigen-sensitized and control dogs. The response to electrical field stimulation and carbamylcholine chloride was greater in strips from larger branches of the same generation when expressed as "tissue stress" (force per unit cross-sectional area of the whole tissue), whereas no difference emerged with use of the more appropriate "smooth muscle stress" (force per unit cross-sectional area of the muscle tissue). The response to histamine was significantly higher in small branches than in large ones, and histamine sensitivity [mean effective concentration (EC50)] was 7.79 x 10(-6) [geometric standard error of the mean (GSEM) 1.20] and 1.49 x 10(-5) M (GSEM 1.14), respectively (P < 0.01). Strips from control and sensitized animals at each site and strips from different generations did not show any significant difference. When we clustered our preparations according to dimensions, the response to histamine was significantly higher in small bronchi than in large ones and histamine EC50 was 8.95 x 10(-6) (GSEM 1.17) and 1.57 x 10(-5) M (GSEM 1.18), respectively (P < 0.05). We conclude that evaluation of muscle response in different tissues requires appropriate normalization. Furthermore, classification into generations is inadequate to study bronchial responsiveness, inasmuch as major differences originate from airway size.

scholarly journals Атрофія альвеолярного відростка верхньої щелепи після пластики гострих післяекстракційних ороантральних сполучень трапецієподібним клаптем

2016 ◽  
Author(s):  
I. S. Sorokivskyi ◽  
K. O. Маshkovа ◽  
I. M. Hot
Keyword(s):  
Vertical Direction ◽  
Cross Sectional Area ◽  
Alveolar Ridge ◽  
Sectional Area ◽  
Alveolar Process ◽  
Pronounced Difference ◽  
Cross Sectional ◽  
Upper Jaw ◽  
And Control ◽  
Tooth Extractions

This article describes the changes in height, width and cross-sectional area of the alveolar process of the upper jaw after the closure of acute postextraction oroantral communications by mobilizing mucoperiosteal trapezoidal vestibular flap. Evaluation of these parameters was performed by measuring on computer tomograms taken on the day of surgery and after six months. It was established that horizontal alveolar ridge atrophy significantly exceeds changes in the vertical direction, and the most pronounced difference observed when comparing the cross-sectional area of the alveolar process in the perioperative and control periods. The obtained results exceed known from the literature parameters of the alveolar process atrophy after tooth extractions not accompanied by the maxillary sinus perforation.

Effects of disuse on growing and adult chick skeletal muscle

1981 ◽  
Vol 48 (1) ◽  
pp. 35-54
Author(s):  
C.R. Shear
Keyword(s):  
Skeletal Muscle ◽  
Postnatal Development ◽  
Latissimus Dorsi ◽  
Plaster Cast ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Motor Endplates ◽  
And Control

The effects of long-term muscle inactivity, throughout post-hatching development, have been examined. Continuous immobilization of the chicken posterior latissimus dorsi (PLD) muscle from the first hour after hatching for varying periods up to 330 days, resulted in a significantly greater decrease in myofibre size (40-64% less than control) than occurred when adult muscles were immobilized for similar periods (20-40% less than control). The myofibre atrophy resulting from long-term immobilization of adult muscle is reversible, after removal of the plaster cast. In contrast, the myofibres immobilized immediately after hatching, for similar periods of time, were unable to recover one the casts were removed. On the basis of myofibre cross-sectional area, 2 populations of cells were seen in muscles immobilized during postnatal development: small myofibres of 0.5-200 micron 2 and larger myofibres of 500–800 micron 2. The distribution of fibre cross-sectional area within immobilized adult muscles was similar to controls, suggesting a uniform response (i.e. atrophy) by all of the myofibres within the muscle. Immobilization in both newly hatched and adult PLD muscles did not appear to alter the pattern of motor endplate distribution within the muscle. Small, multiple motor endplates were observed associated with immobilized and control myofibres near their terminal ends. This finding suggests that the embryonic pattern of myofibre innervation is not entirely lost from all the fibres during postnatal development.

Influence of fertilization on the allometric relations for two pines in contrasting environments

1993 ◽  
Vol 23 (8) ◽  
pp. 1704-1711 ◽  
Author(s):  
Stith T. Gower ◽  
Brent E. Haynes ◽  
Karin S. Fassnacht ◽  
Steve W. Running ◽  
E. Raymond Hunt Jr.
Keyword(s):  
Leaf Area ◽  
Ponderosa Pine ◽  
Cross Sectional Area ◽  
Red Pine ◽  
Stem Diameter ◽  
Sectional Area ◽  
Cross Sectional ◽  
Breast Height ◽  
Allometric Relations ◽  
And Control

The objective of this study was to examine the effect of fertilization on the allometric relations for red pine (Pinusresinosa Ait.) and ponderosa pine (Pinusponderosa Dougl. ex Laws.) growing in contrasting climates. After 2 years of treatment, fertilization did not significantly affect the allometric relations between stem or branch mass and stem diameter for either species. For a similar-diameter tree, current foliage mass and area and new twig mass were significantly greater for fertilized than for control red pine and ponderosa pine. The significant increase in new foliage mass and area occurred in the upper and middle canopy for red pine and middle and lower canopy for ponderosa pine. For a similar-diameter tree, projected (one-sided) leaf area and total foliage mass were significantly greater for fertilized than for control red pine. However, leaf area and total foliage mass did not differ between similar-diameter fertilized and control ponderosa pine because fertilization decreased leaf longevity. The ratios of leaf area/sapwood cross-sectional area measured at breast height (1.37 m) were 0.14 and 0.11 for control plus fertilized red pine and ponderosa pine, respectively, and were greater (but not significantly) for fertilized than for control trees, while the ratios of leaf area/sapwood cross-sectional area measured at the base of live crown were significantly greater for fertilized than for control red pine and ponderosa pine.

scholarly journals Use of Immunofluorescence Technique to Perform a Quantitative Analysis of Masseter Muscle Fibers in Unilateral Posterior Crossbite: A Pilot Study

2021 ◽  
Vol 11 (12) ◽  
pp. 5350
Author(s):  
Giovanna Vermiglio ◽  
Mariagrazia Piancino ◽  
Michele Runci Anastasi ◽  
Giacomo Picciolo ◽  
Antonio Centofanti ◽  
...  
Keyword(s):  
Masseter Muscle ◽  
Muscle Fibers ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Posterior Crossbite ◽  
Affected Side ◽  
The Cross ◽  
And Control ◽  
Contralateral Muscle

Unilateral posterior crossbite is a type of malocclusion that involves morpho-functional characteristics of masticatory muscle, such as the masseter: electrophysiological data have shown that the affected side works less than the contralateral muscle, which shows a normal or increased activity, probably in order to compensate for the affected side. The aim of present work was to measure the diameter and the cross-sectional area of ipsilateral and contralateral muscle fibers to verify if hypertrophy and/or hypotrophy take place in this malocclusion. We used immunofluorescence pictures to measure, using ImageJ software, the diameter and the cross-sectional area of fibers from control and crossbite groups; after that, the data were processed to perform statistical analyses. Results show that the fiber diameters of contralateral muscle are larger than the diameters of ipsilateral and control fibers, and that this difference is statistically significant. No statistically significant difference was found between the fiber diameters of the ipsilateral and control muscles. All these data suggest that, during unilateral posterior crossbite, morphological changes take place in the contralateral masseter muscle, which undergoes hypertrophy, probably to compensate for the low activity of the affected muscle.

Rowing Force Simulation and Control System

2010 ◽  
Vol 164 ◽  
pp. 161-164 ◽  
Author(s):  
Vytautas Grigas ◽  
Alexandra Legha ◽  
Anatolijus Sulginas ◽  
Rymantas Tadas Toločka
Keyword(s):  
Control System ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Hydraulic Loading ◽  
Training Facility ◽  
Force Variation ◽  
Simulation And Control ◽  
The One ◽  
And Control

The rowing force simulation and control system is to be developed to generate the loading on the oar during the rowing stroke most adequate to the one acting during waterborne rowing. The paper presents the methodology of defining the law of change of loading on the oar by changing the cross-sectional area of flow channel of hydraulic loading unit at indoor rowing training facility. An example of the rowing force variation during one cycle obtained by using such a system is provided.

scholarly journals Morphological and Functional Characteristics of the Peroneus Muscles in Patients with Lateral Ankle Sprain: An Ultrasound-Based Study

Medicina ◽  
2022 ◽  
Vol 58 (1) ◽  
pp. 70
Author(s):  
Satoshi Arima ◽  
Noriaki Maeda ◽  
Makoto Komiya ◽  
Tsubasa Tashiro ◽  
Kazuki Fukui ◽  
...  
Keyword(s):  
Connective Tissue ◽  
Ankle Sprain ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Lateral Ankle Sprain ◽  
Lateral Ankle ◽  
Leg Muscle ◽  
And Control ◽  
Muscle Cross Sectional Area

Background and Objectives: The effectiveness of multiple ultrasound evaluations of the peroneus muscles morphology, including muscle cross-sectional area (CSA) and connective tissue, after lateral ankle sprain (LAS) is unknown. This study aimed to measure the peroneus muscles after LAS at three points, adding distal 75% to the conventional measurement points, in order to obtain a detailed understanding of the post-injury morphology and to propose a new evaluation index of the peroneus muscles for multiple LAS. Materials and Methods: Participants with and without LAS (LAS and control groups, 16 each) were recruited. The muscle cross-sectional area (CSA) and muscle echogenicity were measured using a B-mode ultrasound system at 25%, 50%, and 75% proximal to the line connecting the fibular head to the lateral malleolus. The ankle evertor strength was measured using a handheld dynamometer. Simultaneously, the peroneus longus (PL) and peroneus brevis (PB) muscle activities were measured using surface electromyography. Measurements for the LAS side, non-LAS side, and control leg were performed separately. Results: The CSA was significantly higher at 75% on the LAS side than on the non-LAS side and in the control leg. Muscle echogenicity of the LAS side at 75% was significantly lower than that of the non-LAS side and the control leg. Muscle activity of the PL was significantly lower and the PB was higher on the LAS side than on the non-LAS side and in the control leg. Conclusions: The PL was less active than the PB, while the PB was found to be overactive, suggesting that PB hypertrophy occurs due to an increase in the percentage of muscle fibers and a decrease in the connective tissue. Therefore, it is necessary to evaluate the condition of the PL and PB separately after LAS.

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