A Quantitative Analysis of Ciliary Movement by Means of High-Speed Microcinematography

1970 ◽  
Vol 52 (3) ◽  
pp. 675-690 ◽  
Author(s):  
SHOJI A. BABA ◽  
YUKIO HIRAMOTO
Keyword(s):  
High Speed ◽  
Quantitative Description ◽  
Bending Moment ◽  
Viscous Resistance ◽  
Movement Duration ◽  
Ciliary Movement ◽  
Basal Angle ◽  
Active Processes ◽  
Bending Wave ◽  
Ciliary Shaft

1. An optical arrangement for high-speed microcinematography has been designed so as to record ciliary movement, and the movements of single large abfrontal cilia of Mytilus gill have been photographed at 400-500 frames/sec, with brief exposures of 1/20,000 sec. 2. A quantitative description of the movement of the cilium is presented in terms of the changes of the curvature at various regions of the ciliary shaft and of the change of the basal angle. 3. The principle of the description mentioned above is also applied to the movement of the cilium in media of high viscosities, and some parameters of the movement (duration, amplitude of the basal angle, maximum curvature and propagation velocity of the bending wave) are presented. 4. The resistance experienced by the cilium during its beating has been evaluated under some hydrodynamic assumptions, and the flow induced by the cilium and the bending moment of the ciliary shaft due to the viscous resistance have been calculated over a single beat. 5. The change of the degree of bending of the ciliary shaft (curvature) takes place in advance of the change of the bending moment at the same region in the distal as well as in the proximal regions of the ciliary shaft. This fact indicates that active processes are involved in bending and unbending of the ciliary shaft during its beat.

Energetics of Ciliary Movement in Sabellaria and Mytilus

1969 ◽  
Vol 50 (3) ◽  
pp. 733-743
Author(s):  
M. A. SLEIGH ◽  
M. E. J. HOLWILL
Keyword(s):  
High Speed ◽  
Angular Frequency ◽  
Viscous Resistance ◽  
Ciliary Movement ◽  
Viscous Forces ◽  
Ciliary Motion ◽  
Elastic Forces ◽  
Gill Filaments ◽  
Recovery Stroke ◽  
Work Done

1. High-speed cinephotography has been used to study the movements performed by compound cilia from the segmental gills of Sabellaria and from the abfrontal face of the gill filaments of Mytilus. 2. The two types of cilium have distinctly different beat patterns. 3. Equations are derived which allow the calculation of the energy necessary to overcome viscous resistance during the effective and recovery strokes of a cilium in terms of its dimensions and angular frequency. 4. In Sabellaria cilia the energy needed to overcome viscous forces is greater for the effective stroke than for the recovery stroke, but the reverse is true for Mytilus abfrontal cilia. 5. Estimates of the work done to overcome elastic forces are probably too high, but it appears that the elastic work done in the recovery stroke is greater than that in the effective stroke for cilia of both types if the stiffness remains constant throughout the beat. 6. The energy released if each fibrillar arm causes the breakdown of one ATP molecule per beat cycle is greater than that required to overcome viscous resistance to ciliary motion.

scholarly journals Effect of Slam Force Duration on the Vibratory Response of a Lightweight High-Speed Wave-Piercing Catamaran

2015 ◽  
Vol 59 (02) ◽  
pp. 69-84
Author(s):  
Jason John McVicar ◽  
Jason Lavroff ◽  
Michael Richard Davis ◽  
Giles Thomas
Keyword(s):  
High Speed ◽  
Bending Strength ◽  
Experimental Studies ◽  
Bending Moment ◽  
Higher Order ◽  
Acute Angle ◽  
Beam Model ◽  
Higher Order Modes ◽  
Hull Structure ◽  
Vertical Bending Moment

When the surface of a ship meets the water surface at an acute angle with a high relative velocity, significant short-duration forces can act on the hull plating. Such an event is referred to as a slam. Slam loads imparted on ships are generally considered to be of an impulsive nature. As such, slam loads induce vibration in the global hull structure that has implications for both hull girder bending strength and fatigue life of a vessel. A modal method is often used for structural analysis whereby higher order modes are neglected to reduce computational effort. The effect of the slam load temporal distribution on the whipping response and vertical bending moment are investigated here by using a continuous beam model with application to a 112 m INCAT wave-piercing catamaran and correlation to full-scale and model-scale experimental data. Experimental studies have indicated that the vertical bending moment is dominated by the fundamental longitudinal bending mode of the structure. However, it is shown here that although the fundamental mode is dominant in the global structural response, the higher order modes play a significant role in the early stages of the response and may not be readily identifiable if measurements are not taken sufficiently close to the slam location. A relationship between the slam duration and the relative modal response magnitudes is found, which is useful in determining the appropriate truncation of a modal solution.

scholarly journals Model Experimental Study of Damage Effects of Ship Structures under the Contact Jet Loads of Bubble in a Water Tank

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Hailong Chen ◽  
Baoyu Ni ◽  
Wenjin Hu ◽  
Yanzhuo Xue
Keyword(s):  
High Speed ◽  
Oscillation Amplitude ◽  
Bending Moment ◽  
Oscillation Period ◽  
High Speed Photography ◽  
Beam Model ◽  
Water Tank ◽  
Bending Rigidity ◽  
Ship Structures ◽  
Negative Bending

The damage effects of ship structures under the contact jet loads of bubble are studied by using an electric spark bubble as well as high-speed photography. A series of model experiments of ship structures under contact explosion was carried out in a water tank. On the one hand, we monitored the displacement and period of the oscillation of a hull plate of a ship model with a large bending rigidity. On the other hand, we observed the overall motion of a box-beam model with a small bending rigidity. The results show that when the distance parameter is less than 0.6, the bubble jet will impact on the surface of the structure directly, which is defined as “contact bubble jet” herein. The contact bubble jet causes significant local loads on the ship and induces the “sagging moment” effect. This mainly results from the relatively negative bending moment caused by the bubble attached to the hull. With the increase of detonation distance, this negative bending moment decreases. As a result, the oscillation amplitude of the ship structure decreases sharply and the oscillation period reduces gradually.

Using an optimisation process for sailplane winglet design

2016 ◽  
Vol 120 (1233) ◽  
pp. 1726-1745 ◽  
Author(s):  
A. Travis Krebs ◽  
B. Dr. Götz Bramesfeld
Keyword(s):  
High Speed ◽  
High Performance ◽  
Bending Moment ◽  
Total Drag ◽  
Multi Objective ◽  
Traditional Design ◽  
Efficient Alternative ◽  
Cross Country ◽  
The Cost ◽  
Performance Gains

ABSTRACTA multi-objective optimisation process is used to design winglets for a high-performance sailplane. The primary optimisation objective is to maximise the average cross-country speed over a range of thermal strengths. Additional contributions to the cost functions are the limitation of the total drag during high-speed cruise and the additional root bending moment due to the winglet. Rather than being a pure design study, the purpose of the herein presented study is to demonstrate that a multi-objective optimisation approach is a suitable and efficient alternative to the more traditional, experienced-based design approach. The flight performance of the winglet designs are evaluated using a higher-order potential flow method. Results of the optimisation are hand-selected for further analysis. They are compared to a traditionally designed winglet for the same aircraft, designed with similar objectives in mind. The chosen final designs provide an increase in average cross-country speed of 1.5% at lower thermal strengths and 0.4% at higher thermal strengths when compared to the traditional design. When approximating the effects of trim drag due to wing loading and static margin, these performance gains fall to 0.6% and 0.1% respectively, more closely matching the performance of the traditionally designed winglet. The final designs, along with the traditional design, provide performance benefits across all airspeeds of the flight envelope of the base aircraft without winglets.

High Speed Lapping Ellipsoid by Means of a Lapping Tool Bending Method

2007 ◽  
Vol 329 ◽  
pp. 309-314 ◽  
Author(s):  
J.D. Yang ◽  
Q. Liu ◽  
C.L. Tian ◽  
J.W. Guo ◽  
Y.H. Feng
Keyword(s):  
High Speed ◽  
Bending Moment ◽  
Light Energy ◽  
System Structure ◽  
Aspheric Surfaces ◽  
Ellipsoid Method ◽  
Aspheric Optics ◽  
Lapping Machine ◽  
Reduced Light

This paper discusses a new lapping ellipsoid method, which combines high-speed lapping technology with solid abrasives and lapping tool bending method. In this method, a bending moment is acted on lapping tool with solid abrasives, which makes it bend to form a shape on its working surface, which is the same as generant of workpiece shape. This kind tool is used in forming lapping on a high speed lapping machine. With the development of science and technology, the requirements for optics systems become higher and higher, e.g. good quality of imaging, little loss light energy, small size and light weight etc. It is difficult to reach above requirements by using traditional sphere lens/mirrors in optics systems. Aspheric optics elements can be used to solve these problems. In optics systems, by using aspheric optics elements, the number of optics elements can be reduced, the system structure can be simplified, the weight and size of the system can be reduced, light energy loss can be reduced too, imaging errors can be avoided and imaging quality can be improved. Ellipsoid is a kind of surface being used widely within all kinds of aspheric surfaces. The main purpose of this paper is to introduce a method of lapping this kind of surface at high speed.

Experimental Investigation on Flow and Breakup of Two-Dimensional Liquid Jets

2019 ◽  
Author(s):  
Amin Jaberi ◽  
Mehran Tadjfar
Keyword(s):  
High Speed ◽  
Volume Flow Rate ◽  
Quantitative Description ◽  
Sheet Thickness ◽  
Liquid Jets ◽  
Liquid Jet ◽  
High Speed Photography ◽  
Two Dimensional ◽  
Aspect Ratios ◽  
Wide Range

Abstract Studying of injectors with non-circular geometries has recently come to the spotlight of researchers as a potential technique to improve the liquid injection characteristics of different systems. In this work, the flow physics and breakup of two-dimensional liquid jets issued from flat slits into still air were experimentally investigated. Three injectors with aspect ratios of 30, 60 and 90 and thickness of 0.35 mm were manufactured to obtain two-dimensional liquid flow at the nozzle exit. The tests were performed for a wide range of volume flow rate, varying from 10 L/h to 240 L/h. Backlight shadowgraphy and high speed photography were employed to capture the flow dynamics of the jets. In order to capture every detail of the flow, photos of the liquid jet were taken from two views with 90° from each other. Using the visualizations, different regimes of the jet flow were explored and a regime map was proposed to distinguish these regimes based on the non-dimensional parameters of the liquid jet. Moreover, quantitative description of the main features of jet flows were obtained using an in-house image processing program. Measurements of different parameters including convergence length, maximum width, breakup length, sheet thickness to name a few, were conducted.

Dynamic Modelling of Deep-Water Riser With Slug Flow Based on ALE-ANCF

2020 ◽  
Author(s):  
Depeng Liu ◽  
Shangmao Ai ◽  
Liping Sun
Keyword(s):  
Slug Flow ◽  
High Speed ◽  
Dynamic Modelling ◽  
Internal Flow ◽  
Bending Moment ◽  
Time Domain Analysis ◽  
Load Model ◽  
Centrifugal Load ◽  
Load Component ◽  
Euler Bernoulli Beam

Abstract The internal flow in gas-liquid mixing riser often displays a flow pattern known as slug flow, in which gas and liquid are alternately distributed. Dynamic effects due to slug flow is normally most obvious in areas along the riser with high curvature, which is caused by the centrifugal load component. The global riser response to this excitation can be predicted by nonlinear time domain analysis using the load model as described for slug flow conditions. In this study, the riser with internal slug flow is modeled under the framework of Arbitrary-Lagrange-Euler (ALE) description by using the Absolute Node Coordinate Formula (ANCF). The riser is discretized into ANCF cable element based on the Euler-Bernoulli beam assumption, while one-dimensional moving medium modeling method with time-varying density is used to model slug element. Compared with other FEA models of riser subjected to internal flow, the ALE-ANCF model allow easily modeling of complex mass flow and has the advantages of high speed and high precision in handling large deformation of riser, especially for the compliant riser configurations. Numerical simulations of two simplified models are carried out to validate the developed model, then the dynamic response such as displacement, tension force and bending moment of the riser conveying slug flow are analyzed.

scholarly journals Research on Stress Characteristics of Segment Structure during the Construction of the Large-Diameter Shield Tunnel and Cross-Passage

Symmetry ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1246
Author(s):  
Zhongsheng Tan ◽  
Zonglin Li ◽  
Wei Tang ◽  
Xueying Chen ◽  
Junmeng Duan
Keyword(s):  
High Speed ◽  
Mechanical Response ◽  
Mechanical Performance ◽  
Large Diameter ◽  
Bending Moment ◽  
Shield Tunnel ◽  
Railway Network ◽  
Maximum Deformation ◽  
Intercity Railway ◽  
The Stability

With the intensive development of China’s high-speed railway network and intercity railway network, the construction of the large-diameter shield tunnels and cross-passages is gradually increasing. The construction of large diameter shield tunnels and the excavation of cross-passages puts forward higher requirements for the stability and safety of segment structure. Based on the Wangjing tunnel project, this paper studies the segment displacement and mechanical response of the shield tunnel with a diameter of 10.5 m in the process of shield construction and cross-passage construction. The results show that during the construction of large diameter shield tunnels, the vault and invert produce inward displacement, the invert uplift usually is more severe than the vault settlement, and the arch waist on both sides produces outward displacement. Near the segment K (capping block), the mechanical performance of the segment is close to that of the hinge or chain rod, which can only effectively transmit the axial force but cannot resist the bending moment and shear force. During construction of the cross-passage, the maximum deformation and stress of shield tunnel segment are symmetrically located at the interface of the main tunnel and cross-passage. The upper and lower edges of the segment at the interface tend to change from compression to tension. At the same time, the steel bars on the inside and outside of the segment vault and the arch waist change from compressive stress to tensile stress, which can easily lead to segment damage, so these positions can be reinforced by erecting section steel frames before construction.

A model for the micro-structure in ciliated organisms

1972 ◽  
Vol 55 (1) ◽  
pp. 1-23 ◽  
Author(s):  
John Blake
Keyword(s):  
Velocity Field ◽  
Plane Surface ◽  
Bending Moment ◽  
Power Stroke ◽  
Micro Structure ◽  
Mean Velocity ◽  
Slender Bodies ◽  
Recovery Stroke ◽  
The Mean ◽  
Bending Wave

Improved models for the movement of fluid by cilia are presented. A theory which models the cilia of an organism by an array of flexible long slender bodies distributed over and attached at one end to a plane surface is developed. The slender bodies are constrained to move in similar patterns to the cilia of the microorganismsOpalina, ParameciumandPleurobrachia.The velocity field is represented by a distribution of force singularities (Stokes flow) along the centre-line of each slender body. Contributions to the velocity field from all the cilia distributed over the plane are summed, to give a streaming effect which in turn implies propulsion of the organism. From this we have been able to model the mean velocity field through the cilia sublayer for the three organisms. We find that, in a frame of reference situated in the organism, the velocity near the surface of the organism is very small – up to one half the length of the cilium – but it increases rapidly to near the velocity of propulsion from then on. This is because of the beating pattern of the cilia; they beat in a near rigid-body rotation during the effective (‘power’) stroke, but during the recovery stroke move close to the wall. Backflow (‘reflux’) is found to occur in the organisms exhibiting antiplectic metachronism (i.e.ParameciumandPleurobrachia). The occurrence of gradient reversal, but not backflow, has recently been confirmed experimentally (Sleigh & Aiello 1971).Other important physical values that are obtained from this analysis are the force, bending moment about the base of a cilium and the rate of working. It is found, for antiplectic metachronism, that the force exerted by a cilium in the direction of propulsion is large and positive during the effective stroke whereas it is small and negative during the recovery stroke. However, the duration of the recovery stroke is longer than the effective stroke so the force exerted over one cycle of a ciliary beat is very small. The bending moment follows a similar pattern to the component of force in the direction of propulsion, being larger in the effective stroke for antiplectic metachronism. In symplectic metachronism (i.e.Opalina) the force and bending moment are largest in magnitude when the bending wave is propagated along the cilium. The rate of working indicates that more energy is consumed in the effective stroke forParameciumandPleurobrachiathan in the recovery stroke, whereas inOpalinait is found to be large during the propagation of the bending wave.

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