scholarly journals Seat pitch and comfort of a staggered seat configuration

Work ◽  
2021 ◽  
Vol 68 (s1) ◽  
pp. S151-S159
Author(s):  
Zhihui Liu ◽  
T. Rotte ◽  
S. Anjani ◽  
P. Vink
Keyword(s):  
Longitudinal Axis ◽  
The Other ◽  
Sitting Position ◽  
Lateral Direction ◽  
Top View ◽  
Design Freedom ◽  
Cabin Interior ◽  
Physical Dimensions

BACKGROUND: Staggered seats are a solution for the Flying-V aircraft, where the cabin’s longitudinal axis has a 26 degrees angle with respect to the direction of flight, to compensate for an otherwise oblique sitting position. However, little is known on acceptable pitches in this staggered configuration. OBJECTIVE: The goal of this research is to evaluate the comfort of different pitches for seats that are staggered relative to the cabin’s longitudinal axis. METHODS: Two rows of staggered seats are positioned at three different pitches (27, 29 and 31 inches). 53 participants were seated in each setup. For each, a questionnaire was completed including questions on comfort and discomfort, top view photos were taken to analyse postures and physical dimensions were recorded to define passengers’ space. RESULTS: Comfort as well as discomfort were significantly different for the three setups. The comfort at 27 inches was seen as unacceptably low. The 29 and 31-inch configurations showed to result in acceptable levels of comfort, comparable to higher-end seating layouts. There were very little complaints about space in lateral direction (elbow and seat width), showing the advantage of having your won armrest and shoulder space in the staggered configuration. Interesting was that at larger pitches more complaints were found for the seat characteristics, probably in the shorter pitch the other discomfort was overruling this. CONCLUSION: The 26-degree staggered configuration offers improvements in shoulder- and elbow-space. The results for the 29- and 31-inch are expected to allow enough design freedom for further exploration of such a configuration for the Flying-V cabin interior.

scholarly journals Effects of Bucket Type and Angle on Downstream Nappe Wind Caused by a Turbulent Jet

2019 ◽  
Vol 16 (8) ◽  
pp. 1360 ◽  
Author(s):  
Jijian Lian ◽  
Junling He ◽  
Wenjuan Gou ◽  
Danjie Ran
Keyword(s):  
Wind Velocity ◽  
Great Influence ◽  
Vertical Direction ◽  
Physical Experiment ◽  
Turbulent Jet ◽  
The Other ◽  
Rainfall Distribution ◽  
Lateral Direction ◽  
Flood Discharge ◽  
Operational Safety

The downstream nappe wind caused by flood discharge has a great influence on the rainfall distribution, the operational safety of dams, and their surrounding ecological environments. A physical experiment was conducted to measure the spatial distribution of the downstream nappe wind and the splash for a continuous bucket (CB) and a tongue-shaped bucket (TB) for five bucket angles (40°, 45°, 50°, 55°, and 60°). The experimental results demonstrate that the trajectory width and height of the nappe increase as the angles increase, but the effect on the length is converse. The wind velocity and splash weight of the two buckets decrease along the flowing direction. In the lateral direction, the wind velocity and splash weight for the CB decrease as y increases, but the wind velocity of the TB trends to humplike; its splash weight decreases near the axis of the bucket, and is stable in the other region. In the vertical direction, the velocity for the CB increases and then decreases as z increases, but that for the TB decreases monotonously. The velocity of the wind and weight of the splash for the CB decreases with the increasing angles, but those of the TB peak at 45°. The findings are useful for the more accurate prediction of rainfall.

Coordinated righting behaviour in locusts

2001 ◽  
Vol 204 (4) ◽  
pp. 637-648 ◽  
Author(s):  
A.A. Faisal ◽  
T. Matheson
Keyword(s):  
Driving Force ◽  
Flat Surface ◽  
Longitudinal Axis ◽  
Upright Position ◽  
The Body ◽  
The Other ◽  
Legged Robots ◽  
Naturally Occurring ◽  
Key Features ◽  
Low Levels

A locust placed upside down on a flat surface uses a predictable sequence of leg movements to right itself. To analyse this behaviour, we made use of a naturally occurring state of quiescence (thanatosis) to position locusts in a standardised upside-down position from which they spontaneously right themselves. Locusts grasped around the pronotum enter a state of thanatosis during which the limbs can be manipulated into particular postures, where they remain, and the animal can be placed upside down on the ground. When released, thanatosis lasts 4–456 s (mean 73 s) before the animal suddenly becomes active again and rights itself within a further 600 ms. Thanatosis is characterised by very low levels of leg motor activity. During righting, one hind leg provides most of the downward force against the ground that rolls the body around a longitudinal axis towards the other side. The driving force is produced by femoral levation (relative to the body) at the trochanter and by tibial extension. As the animal rolls over, the hind leg on the other side is also levated at the trochanter, so that it does not obstruct the movement. The forelegs and middle legs are not required for successful righting but they can help initially to tip the locust to one side, and at the end of the movement they help stop the roll as the animal turns upright. Individual locusts have a preferred righting direction but can, nevertheless, roll to either side. Locusts falling upside down through the air use both passive and active mechanisms to right themselves before they land. Without active movements, falling locusts tend to rotate into an upright position, but most locusts extend their hind leg tibiae and/or spread their wings, which increases the success of mid-air righting from 28 to 49 % when falling from 30 cm. The rapid and reliable righting behaviour of locusts reduces the time spent in a vulnerable upside-down position. Their narrow body geometry, large hind legs, which can generate substantial dorsally directed force, and the particular patterns of coordinated movements of the legs on both sides of the body are the key features that permit locusts to right themselves effectively. The reliability of autonomous multi-legged robots may be enhanced by incorporating these features into their design.

WATER FLOWS AROUND THE COMB PLATES OF THE CTENOPHORE PLEUROBRACHIA PLOTTED BY COMPUTER: A MODEL SYSTEM FOR STUDYING PROPULSION BY ANTIPLECTIC METACHRONISM

1993 ◽  
Vol 177 (1) ◽  
pp. 113-128 ◽  
Author(s):  
D. Barlow ◽  
M. A. Sleigh ◽  
R. J. White
Keyword(s):  
Computer Program ◽  
Water Flow ◽  
High Speed ◽  
Beat Frequency ◽  
Longitudinal Axis ◽  
Model System ◽  
The Other ◽  
Contour Maps ◽  
Water Flows ◽  
Pleurobrachia Pileus

Patterns of water flow around steadily beating comb plates of Pleurobrachia pileus were tracked using suspended plastic beads. The positions of the beads and the comb plates in the plane of the central longitudinal axis of the comb row were digitised from high-speed cine films covering several beat cycles. All of the data from each sequence were combined using a computer program which integrated them into a standard cycle, and the resulting data were plotted by a second computer program to produce charts for different stages in the beat cycle showing the flow velocity at a grid of points. On these charts, contour maps were drawn to indicate the speed and direction of the water flow. Water is drawn towards each comb row from ahead and from the sides and accelerates strongly backwards in a fairly narrow stream which joins those from the other seven comb rows at the rear of the animal. At a beat frequency of 10 Hz the comb plates move with a tip speed of up to 70 mm s-1 in their effective stroke; they have an estimated Reynolds number of 9 in this stroke. Changes in inter- plate volume between adjacent antiplectically coordinated plates are very important in propulsion, particularly near the end of the effective stroke when pairs of adjacent plates close together and cause the high-speed water from around the ciliary tips to be shed into the overlying stream as a series of jets at speeds of 50 mm s-1 or more. The antiplectic coordination of the comb plates makes a major contribution to the efficiency of propulsion.

scholarly journals Extensometer for Determining Strains on a Tensile and Torsion Simultaneous Load

Sensors ◽  
2020 ◽  
Vol 20 (2) ◽  
pp. 385
Author(s):  
Viorel Goanta
Keyword(s):  
Simultaneous Measurement ◽  
Tensile Load ◽  
Longitudinal Axis ◽  
The Other ◽  
Bending Moments ◽  
Strain Process ◽  
Electric Signals ◽  
Measured Process

The paper presents an extensometer designed to measure two mechanical strains at the same time—one from tensile load and the other from torsion load. Strain transducers provide different electric signals, which, after calibration, lead to the simultaneous measurement of linear (ε) and angular (γ) strains. Each of these two signals depends on the measured process and is not influenced by the other strain process. This extensometer is designed to be easily mounted on the sample with only two mounting points and can be used to measure the combined cyclical fatigue of tensile and torsional loadings. This extensometer has two bars—one rigid, reported at the resulting stress points, and one elastic and deformable. The elastic deformable bar has two beams with different orientations. When the sample is deformed, both beams are loaded by two bending moments (perpendicular to each other and both perpendicular on the longitudinal axis of the bars).

Correlation of Patellar Tracking Pattern With Trochlear and Retropatellar Surface Topographies

2000 ◽  
Vol 122 (6) ◽  
pp. 652-660 ◽  
Author(s):  
A. M. Ahmed ◽  
N. A. Duncan
Keyword(s):  
Three Dimensional ◽  
Knee Extension ◽  
The Other ◽  
Lateral Direction ◽  
Dial Gage ◽  
Passive Restraint ◽  
Out Of Plane ◽  
Fresh Frozen ◽  
Six Degree Of Freedom ◽  
Anterior Posterior

The study was aimed to test the hypothesis that in the knee extension range 100 to 30 deg, the patellar “out-of-plane” tracking pattern is controlled by the passive restraint provided by the topographic interaction of the patellofemoral contacting surfaces. The out-of-plane tracking pattern, i.e., the pattern of patellar displacements not in the plane of knee extension/flexion, consists of translation in the medial–lateral direction, and rotations about the anterior–posterior axis (spin) and the proximal–distal axis (tilt). Using 15 fresh-frozen knees subjected to extensor moment magnitudes comparable to those in the “static-lifting” activity (foot-ground reaction=334 N), the patellar displacements were measured using a calibrated six-degree-of-freedom electromechanical goniometer. The topographies of the trochlear and retropatellar surfaces were then measured using a calibrated traveling dial-gage arrangement and the same coordinate system used for the displacement measurements. Three indices were defined to quantify particular natural features of the three-dimensional topographies that are expected to control the patellar displacements. Correlation of the indices with their corresponding displacements showed that topographic interaction was significant in the control of all three displacements. However, for patellar spin, unlike for the other two displacements, the direction of the active quadriceps tension vector was also a significant controlling factor. Patellar medial–lateral translation was found to be controlled dominantly by the trochlear topography, while retropatellar topography also had a significant role in the control of the other two displacements. [S0148-0731(00)01406-0]

Design of a Wave Shifter with the Exit Direction Controllable Based on Coordinate Transformation Theory

2013 ◽  
Vol 798-799 ◽  
pp. 590-593
Author(s):  
Wen Yan Yan ◽  
You Gang Ke
Keyword(s):  
Numerical Simulations ◽  
Coordinate Transformation ◽  
Longitudinal Axis ◽  
The Other ◽  
Wave Direction ◽  
Transformation Theory ◽  
Transformation Medium ◽  
Theoretical Design ◽  
Constitutive Parameters

We propose a wave shifter with the exit wave direction controllable by using a transformation-medium slab. The coordinate transformation takes two steps. One is along the longitudinal axis to realize shift and the other is on the transversal axis to adjust the exit directon. By using coordinate transformation theory, the constitutive parameters of the slab are obtained. Numerical simulations are further given to validate the performance of the theoretical design.

Research on Mechanical Conditions of Vehicle Rollover at Corners

2014 ◽  
Vol 1046 ◽  
pp. 187-190
Author(s):  
Kai Guo Qian
Keyword(s):  
Reaction Force ◽  
Longitudinal Axis ◽  
Road Surface ◽  
The Other ◽  
Lateral Movement ◽  
The Road ◽  
Curvilinear Motion ◽  
Automotive Structures ◽  
Vehicle Rollover ◽  
On The Road

Vehicle rollover refers to a dangerous lateral movement of a vehicle in contact with the ground when it rotates around its longitudinal axis to a certain angle degree or greater angle during moving. There are many factors that could cause the vehicle's rollover, including automotive structures, road conditions and the driver's condition. vehicle rollover can be divided into two categories, one category is tripped rollover (trPPiedorllover), the other is a rollover (maneuve curve caused by motion: niduecdorllove) The former refers to the generation of lateral slip when the vehicle is moving, and the obstacle on the road surface collides sideways with it its "tripped" The latter refers to the rollover caused by the vertical reaction force inside the wheels of the vehicle reaching to zero because sideways acceleration of the has exceeded a certain limit when the vehicle moves on the road (including a lateral ramp). In this paper, only the rollover caused by curvilinear motion will be studied.

Methods of Attaching Skis and Footwear for Skiing1

2019 ◽  
pp. 38-43
Author(s):  
K. B. E. E. Eimeleus
Keyword(s):  
Longitudinal Axis ◽  
Solid Support ◽  
The Other ◽  
Distributed Pressure

This chapter discusses methods for attaching skis. The methods for attaching ski to foot have been through just as many changes as those undergone by skis themselves. Although currently there is no single definitive type of binding that is the unanimous best choice, there are still many quite satisfactory ones. Above all, these methods must meet the following requirements: to give as much solid support for the feet as possible so that the foot is always aligned with the ski; to allow for more movement of the foot along the longitudinal axis of the ski without causing restriction when kneeling; to be put on and taken off quickly and conveniently; to be durable, uncomplicated, and easy to repair; to have just enough evenly distributed pressure without making one's feet cold; to be adjustable for a variety of footwear; and to be moderately priced. Furthermore, the chapter discusses two main groups of bindings: one for running and the other for mountain skis.

Existence of Periodic Solution for Beams With Harmonically Variable Length

1997 ◽  
Vol 119 (3) ◽  
pp. 485-488 ◽  
Author(s):  
E. Esmailzadeh ◽  
G. Nakhaie-Jazar ◽  
B. Mehri
Keyword(s):  
Periodic Solution ◽  
Fixed Point ◽  
Nonlinear Function ◽  
Longitudinal Axis ◽  
Equation Of Motion ◽  
The Other ◽  
Sufficient Condition ◽  
Vibrating String ◽  
The Stability ◽  
Special Case

The transverse oscillatory motion of a simple beam with one end fixed while driven harmonically at the other end along its longitudinal axis is investigated. For a special case of zero value for the rigidity of beam, the problem reduces to that of a vibrating string with its corresponding equation of motion. The sufficient condition for the periodic solution of the beam was determined using the Green’s function and Schauder’s fixed point theorem. The criterion for the stability of the system is well defined and the condition for which the performance of the beam behaves as a nonlinear function is stated.

Slowing of carotid-cardiac baroreflex with standing and with isometric and dynamic muscle activity

1996 ◽  
Vol 271 (4) ◽  
pp. H1363-H1369 ◽  
Author(s):  
P. Sundblad ◽  
D. Linnarsson
Keyword(s):  
Muscle Activity ◽  
Sympathetic Activity ◽  
Maximum Voluntary Contraction ◽  
Voluntary Contraction ◽  
The Other ◽  
Sitting Position ◽  
Arm Exercise ◽  
Mean Values ◽  
Leg Exercise ◽  
Male Subjects

We hypothesized that the carotid-cardiac baroreflex becomes slowed in conditions with increased sympathetic activity. Changes in heart rate (HR) and blood pressure in response to 10-s trains of 50-mmHg pulses of neck suction (NS) were studied in six male subjects during supine rest, upright rest, isometric arm exercise at 30% of maximum voluntary contraction, and dynamic leg exercise at 100 W in the sitting position. Estimated mean carotid distending pressure increased by approximately 20 mmHg with 50-mmHg, QRS-triggered, pulsatile NS. Repeated NS sequences were performed in each condition. The amplitude of the bradycardic response was highly variable among the subjects and did not differ significantly between conditions, mean values ranging from 0.3 to 0.6 beats.min-1.mmHg-1. In supine rest, the full bradycardic response appeared within < 1 s, i.e., during or immediately after the R-R interval of the first NS pulse. In the other conditions it took significantly longer, 2-3 s or three to seven R-R intervals, for the full HR responses to develop. Our results support the notion that the carotid-cardiac baroreflex in humans becomes slowed under conditions of concurrent sympathetic stimulation.

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