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.

Observations on the number of nuclei within the fibres of some red and white muscles

1977 ◽  
Vol 23 (1) ◽  
pp. 269-284 ◽  
Author(s):  
I.G. Burleigh
Keyword(s):  
Cross Sectional Area ◽  
Growth Potential ◽  
Muscle Fibres ◽  
Sectional Area ◽  
Adult Rats ◽  
Cross Sectional ◽  
Physiological Properties ◽  
Phasic Type ◽  
The One ◽  
Red And White Muscles

Nuclei have been enumerated in muscle fibres of different physiological properties within adult rats and rabbits. Almost invariably, and regardless of muscle type, there is a direct relationship between the cross-sectional area (or fibre breadth) of muscle fibres and the number of nuclei within them. The one exception occurred in muscles of older rats where increased nuclear numbers do not always appear to result in broader muscle fibres. The greater complement of nuclei in broader fibres is accompanied by larger amounts of cell substance per nucleus. Confirming early observations in the literature, red fibres of the slow-phasic type have more nuclei than have white, fast-phasic fibres of similar breadth. These conclusions are not vitiated by differences in the number of nuclei within capillaries or in satellite cells, by differences in nuclear length or by variation in the degree to which fibres are contracted. In respect of their complement of nuclei, and the average amount of cell substance formed per nucleus the small red fibres that occur within muscles of predominantly fast-phasic character appear to be fast-rather than slow-phasic in type. When the number of nuclei observed per fibre is plotted against fibre cross-sectional area, the shapes of the resulting distributions suggest that estimates of muscle nuclei may be valuable not only as an index of growth potential, but of the extent to which that potential is expressed. In one muscle, the above distribution was of a form which indicated that some fibres may have formed abnormally large amounts of protein per nucleus. However, this was not adequately confirmed. Various factors have been investigated that are relevant to the accuracy of enumerating nuclei and measuring fibre breadths.

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.

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.

scholarly journals Design and simulation of an optimized small wind turbine

2021 ◽  
Author(s):  
◽  
Norberto Fernando Soares Sanjimba
Keyword(s):  
Control System ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Cost Of Energy ◽  
Small Wind Turbines ◽  
The Cost ◽  
Large Wind

The volatility of fossil fuel's price, pollution, and emission associated with converting fos- sil fuel into a useful type of energy led man to search for more sustainable energy sources that are pollution-free and renewable. Today, renewable energy technologies, such as solar and large wind turbines, are developed to a stage of maturity, having the cost of produc- ing electricity dropping signi􏰀cantly in the last decade, therefore making these technologies competitive with the traditional counterpart. The cost of producing electricity through small wind turbines is still high compared to large wind turbines or photovoltaic technology. For small wind turbines to successfully compete with other technologies and contribute to the diversi􏰀cation of o􏰈-grid technology, further research is needed to reduce the levelised cost of energy (LCOE). Therefore, this study aims to reduce the levelised cost of energy (LCOE) of small wind turbines. To achieve the ob- jective, a 10 kW wind turbine operating at a site of an average wind speed of 7.5 m/s was designed, optimized, and simulated. With low LCOE in mind, the turbine components were designed as simple as possible to reduce manufacturing costs. The blades are made of uniform cross-sectional area, which made possible to use aluminum as the blade material, and the blade cross-sectional area is made out of a high lift airfoil. The hub is made of aluminum and modelled and designed as a disc with holes to bolt the blades and attach the main shaft. The mainframe is treated as a thick plate with a proper arrangement to connect the generator, the main and yaw bearings, the tail support, and any other ancillaries needed. An octal tapered tower with a height of 20 m made of steel was designed and optimized for low weight. The electrical power is to be produced by a direct drive variable speed permanent magnet synchronous generator. The control system is designed in such a way that allows the turbine to operate in maximum power e􏰊ciency for any speed below the rated speed, and to increase reliability, a sensorless control system is suggested. The research started with a broad review of the relevant literature on wind turbines in general and small wind turbines. The turbine blades design began by analysing the aero- dynamic performance of the blade. To accomplish that, XFoil was used to generate the aerodynamic parameters of the airfoil, the Blade Element Momentum (BEM) method was used to estimate the blades' aerodynamic performance, and Qblade was employed to com- pare the results, and Computational Fluid Dynamics (CFD) was used to verify the results. The preliminary design was done using standard IEC 61400-2 to obtain the load cases, and general engineering formulas, CFD and Finite Element Analysis (FEA) was used to analyse the load in the components according to IEC 61400-2, FAST-V7 was used to simulate the turbine's overall performance, standard formulas were used to evaluate the economic perfor- mance of the design, MatLab was used to perform all needed calculations. In this study, it is evident that using standard IEC 61400-2 to estimate the load, gyroscopic load components dominate the design, and the control system must be used to limit those loads. The designed turbine has relatively high e􏰊ciency and low LCOE.

Relationships Between Cutting Force Variations and Cutting Factors in Plain Milling Operations. Part 1: Plain Milling With a Single-Toothed Helical Cutter

1981 ◽  
Vol 103 (2) ◽  
pp. 165-173
Author(s):  
S. Kato ◽  
T. Yamada ◽  
M. Hashimoto ◽  
K. Yamaguchi
Keyword(s):  
Cutting Force ◽  
Optical Method ◽  
Constant Width ◽  
Cross Sectional Area ◽  
Experimental Results ◽  
Sectional Area ◽  
Cross Sectional ◽  
Milling Operations ◽  
Variation Patterns ◽  
Force Variation

In plain milling operations with a single-toothed helical cutter, three components of cutting force are measured simultaneously and continuously corresponding to the varying cross-sectional area of cut by means of a unique optical method. Based on the measured cutting force variation in a constant width of cut, some required cutting force variations in various widths of cut can be obtained by summing up the overlapped basic cutting force variation patterns. Relationships between cutting force variations and cutting factors in plain milling operations are explained on the basis of the experimental results and the expanded results of experiments.

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