Questions related to Motion
I have thought and written that a fourth time dimension is required to enable motion in space, else object motion in three dimensions would create an overlapping smeared mess. But would it? Given matter-wave awareness from particles to de Broglie waves of objects, may we not acknowledge that the wave content of an object could become the object displaced in three dimensions? It would have moved without overlapping and smearing. Or would non-linear wave interactions during the event force us back to the original idea of four actual dimensions with a separate object at each now? What is time in either process?
In other threads it was suggested that kinetic energy and potential energy compete for curvature. Kinetic energy was said to bend space backward compared to gravity. LaGrange function is well accepted as a factor in determining how celestial bodies move. Action S is calcu;ated for all the possible movements and the smallest S identifies the motion. In GR the calculations predict gravity opposing light and slowing light when approaching.
Questions of gravitational red shift arise which seems to say gravity attracts light.
Dicke supported a competing theory which predicts light losing energy as it departs from a star.
If Dicke is correct then GR is in doubt.
In LaGrange Function Why Is Potential Energy Subtracted From Kinetic Energy?
Perception is not the ultimate guide for knowledge but as Gallileo captured the actual and empirical, not necessarily the real, similar concerns arise.
In general, the repercussions of Reduction arise because what is actual, i.e final instantiation of underlining process, is not all the story. Further omissions come from the empirical approach since sense means are not always valid projectors of the actual.
Gallilean approach has yielded a framework that empowered our comprehension & ability to define/describe phenomena in the realm of the actual& empirical. His treatise should not be considered more than this i.e descrining the nature of the real and its dynamics.
The reduction of change to motion has been noted but little has been argued about its shortfalls in epistemic practice. This reduction is part of the reduction of the real to the actual since it omits any need to refer to the real to make its claims functional. It also removes philosophical or anthropocentric notions of growth and ultimate ends which is good in one sense but in a pure "reductionist shortfalls" point of view is still a problem dimain restriction.
The description of motion with mathematics is another point neglected. Motion can be described qualitatively or conceptual but such a framework has not been devised.
Recent work (Smolin, 2021) tries to overthrow Gallilean reduction of change to motion and representation of motion solely mathematically.
Summary of philosophical approaches to physics projects
**reductionism.. Helps make sense in a physical world overloaded with information. 2 motion, 3 dynamics Laws that everything else dubordinates to-akin an ecpert with main files, mental folfers and subfolders in his head that contains all info about it - so Gallileo has a strong point here in his "error" of reducung motion to math representation etc
**realism-axiological, epistemological, etc
Simulations based on Newtonian gravitational theory predict the perihelion advance or precession of Mercury’s orbit to be approximately 532 arc seconds per century [see reference 3 below]. However, the observed value is closer to 575 arc seconds per century . Most sources attribute this discrepancy to space-time curvature as described by Einstein’s theory of General Relativity. However, I cannot find any papers documenting a General Relativity based Solar System n-body simulation prediction of Mercury’s precession for comparison.
 CLEMENCE, G. M. 1947 The Relativity Effect in Planetary Motions
 Ryan S. Park et al 2017 AJ 153 121 Precession of Mercury’s Perihelion from Ranging to the MESSENGER Spacecraft
 Souren P. Pogossian 2021 Comparative study of Mercury's perihelion advance
Why isn't the velocity of light given by the speed of the observer plus the speed of the light (addition of velocities)?
Why does the light ray slow down and compensate or speed up and compensate for your motion, so that it is always travels at the speed of light? notwithstanding your motion?
In short, what is the mechanism that means the velocity of light always remains the same, irrespective of the motion of the torch issuing the light ray?
Examples in physics are Kinematics (2 categories, all motion experience), Standard model (3 generations, all Particle experiences)
I want to calculate the range of motion of the lumbar model in all 6 directions (Flexion, Extension, Lateral Bending Right and left, Torsion Right and Left) so that I can verify how many degrees my model rotates in one direction. My model contains cortical and cancellous parts of L3 and L4, two facet joints on each vertebra, spring as a ligament, one annulus fibrosis, Five rings of fiber, one nucleus pulpous, and a plate on top of L3 (to apply pressure as a load). My model is working properly in all directions but I don't know how to calculate the ROM. If you can help me I would be very grateful.
Thanks in advance
I have been trying to use ArtRepair and I have some questions regarding the preprocessing I am doing, and I would be very grateful if you could answer some of them. The preprocessing I am doing is as follows:
1. “art_slice”: Normally the threshold has to be modified until it is inferior to 5%.
- IS IT OKAY IF THE THRESHOLDS ARE DIFFERENT FOR DIFFERENT PARTICIPANTS?
- WHAT TO DO IF THE MASK CREATED IS NOT ACCURATE (THERE SEEMS TO BE DATA OUTSIDE THE HEAD)?
2. Slice timing
3. Realign & reslice
(4). art_despike IF “visual inspection of the ArtGlobal figure uncovers greater than +/-1 % drift in the mean global signal across the entire time series”.
- IS THERE A WAY TO CALCULATE THE PERCENTAGE OF THE SIGNAL DRIFT IN ORDER TO CHECK IF IT’S GREATER THAN +/-1 %? (For example by calculating the % of decrease between the maximum and the minimum value OR the first and the last image?
(9). art_global: apply if art_despike was not applied.
When using art_global, users are asked “always repairs 1st scan of each?”. IF I ALREADY DELETED THE TWO FIRST DUMMY SCANS, SHOULD I REPLY “YES” OR “NO”?
- IF THERE IS TOO MUCH MOTION, IS IT OKAY TO SKIP “art_motionregress” AND USE THE “.rp” FILE FROM THE REALIGMENT STEP AS MOTION REGRESSORS?
- WHEN USING MOTION REGRESSORS, IS IT BETTER TO LEAVE THE SCAN-TO-SCAN MOVEMENT THRESHOLD AT 0.5 mm/TR?
- IS IT A PROBLEM IF ART_DESPIKE IS PERFORMED FOR SOME PARTICIPANTS AND ART_GLOBAL FOR OTHERS?
Finally, I would like to know if you believe the preprocessing I described is correct or not.
I would be extremely grateful if any of you could answer to these questions, it would be very helpful!
I am trying to determine the relative motion between two surfaces in contact. Although I know how to calculate the relative motion, I don't know how to extract the paired nodes (closest nodes) of surfaces in ABAQUS when my geometry of study is undeformed.
For relative motion I will be using the following formula:
If there are contact surfaces named A and B, where there are i-th number of nodes:
X - Relative motion: square root( ( (X Deformed Node1B - X Deformed Node 1A) - (X Undeformed Node1B - X Undeformed Node 1A) )^2 )
Y - Relative motion: square root( ( (Y Deformed Node1B - Y Deformed Node 1A) - (Y Undeformed Node1B - Y Undeformed Node 1A) )^2 )
Z - Relative motion: square root( ( (Z Deformed Node1B - Z Deformed Node 1A) - (Z Undeformed Node1B - Z Undeformed Node 1A) )^2 )
Total relative motion: square root ( (X - Relative motion)^2 + (Y- Relative motion)^2 + (Z - Relative motion)^2 )
Please let me know if I can make my question more understandable or if there's more information required to make it clearer.
The Chandler wobble or Chandler variation of latitude is a small deviation in the Earth's axis of rotation relative to the solid earth, which was discovered by and named after American astronomer Seth Carlo Chandler in 1891. It amounts to change of about 9 metres (30 ft) in the point at which the axis intersects the Earth's surface and has a period of 433 days. This wobble, which is an astronomical nutation, combines with another wobble with a period of one year, so that the total polar motion varies with a period of about 7 years.
Is this wobble sustained by an internal or external mechanism?
As a result of bottom uplift during an earthquake, an ordinary trochoidal surface (transverse) wave occurs. There are no other opinions. The first slide shows the generally accepted wave generation mechanism. The second slide shows a diagram of the motion of particles in a surface wave. Everyone thinks so. In 2006 in Vienna, at the Intergovernmental Oceanographic Commission's Tsunami (EGU2006), I asked everyone why a tsunami begins with an outflow of water from the coast. My question was of no interest. The third slide shows that the water will first move away from the shore. The fourth slide shows that in the open ocean there is a hole first and then a mountain. Maybe this is not a trochoidal wave, but a Rayleigh wave? The scheme of the Rayleigh wave is shown on the fifth slide. If this is so, then the tsunami formation mechanism (first slide) is wrong?
First question: First, is this possible? Then (if any) how much has this been done judging from the title (especially from Poincare's first principles: Les Methodes Nouvelles de la Mechanic Celeste )?
First point: Cornelis de Jager (distinguished solar scientist/winner of the Hale, Janssens (sic?) RAS Gold Medal and the Russian and German astronomical societies' awards etc. - not his full list or honors or science awards) did a paper: "Do Planetary Motions Drive Solar Variability?" with Versteegh, J.M, Solar Physics (2005) 229:175-179. His abstract: "We examine the occasionally forwarded hypothesis that solar activity originates by planetary Newtonian attraction on the Sun. We do this by comparing three accelerations working on solar matter at the tachocline level: Those due to planetary tidal forces, to the motion of the Sun around the planetary system’s centre of gravity, and the observed accelerations at that level. We find that the latter are by a factor of about 1000 larger than the former two and therefore cannot be caused by planetary attractions. We conclude that the cause of the dynamo is purely solar."
Second point (ventured) to Second question: There is a dearth, judging by Kees's answer (and I hazard error here) of analyses of statistical probabilities of "chaotic, unpredictable" effects planets could place upon the sun that Poincare's updated mathematical view of the celestial clockwork (of Newton) might deliver upon de Jager's "three accelerations."
If all of this is silly, please say so.
1. If one of the twin brothers rides on a rocket, makes a U-turn while moving at sub-light speed, and returns to meet again, the time progress of the one who moved by rocket will be delayed.
2. If the twin brothers ride on a rocket in the opposite direction, move at sub-light speed, make a U-turn at the same time, proceed in the opposite direction and meet again, the progress of both times will be the same.
Is it a contradiction of special relativity that asymmetric motion 1 and symmetric motion 2 are not the same?
I am using a Shimadzu AGS-J tensile/ flex testing machine without an extensometer.
The values for tensile strength, flexural strength, % elongation at yield, and % elongation at break are similar to those measured by another lab on the same series of samples. However, the modulus of elasticity (slope of stress/strain) in the initial linear portion of the stress-strain curve is much lower than in the other lab. The load cell and machine motion are checked several times and are within specs. The modulus is measured as a slope between 0.025% and 0.25% strain.
In dynamic analyses, the size of the element mesh is based on the shortest wave length of interest which is defined from the dominant frequency of the input motion. It should also depend on the vibration frequencies of the analysed system. Furthermore, the wave length should be calculated with the degraded (secant) shear wave velocity: how is the latter estimated?
See the corresponding blog at https://restframe.blogspot.com
The detection of the existence of the Cosmic Microwave Background Radiation (CMBR) from everywhere around in the universe has puzzled theorists. Not least because of the discovery of a Doppler effect in the data that can only be interpreted as direct related to the velocity and the direction of the motion of the solar system. But if it is correct we have to accept that there exist a rest frame in the universe. Actually we can determine the existence of absolute space and that is not in line with the “belief” of most of the theorists.
There is another method to verify the results: counting the numbers and measuring the brightness of galaxies from everywhere around. The first results – using visible light – were not convincing. But a couple of days ago The Astrophysical Journal Letters published a paper from Jeremy Darling with results that were obtained with the help of radio waves: “The Universe is Brighter in the Direction of Our Motion: Galaxy Counts and Fluxes are Consistent with the CMB Dipole” (https://iopscience.iop.org/article/10.3847/2041-8213/ac6f08).
In other words, it is real. We can determine the existence of "absolute space". Moreover, we know from set theory (mathematics) that absolute space and phenomenological reality must share the same underlying properties otherwise we cannot detect the existence of absolute space. The consequence is that absolute space has a structure too, because phenomenological reality shows structure.
None of the grand theories in physics is founded on the structure of absolute space. Therefore we are facing a serious problem in respect to the foundations of theoretical physics (the conceptual framework of physics).
Science Journals (gsjournal.net)
In order to avoid a demand for perfect symmetry in gravitating bodies Newton's law should be applied to small elements in the gravitating body and then integrated. After doing that we see that uniting his law to Fatio's model is possible. Fatio's law implies an ether wind in radial direction to the gravitating body. Therefore, the ether can be falling (perhaps with the same speed as the escape velocity). By doing this assumption we can explain the Pioneer anomaly and the Big Bang as illusions due to ether motions and not motions of bodies.
This explained in the attachment.
Regards from ___ John-Erik
I've successfully simulated the closure of a flapper non-return valve as illustrated.
The inlet velocity increases gradually with a specific acceleration.
The following UDF is used to specify the motion of the flapper:
DEFINE_SDOF_PROPERTIES(flappers_motion, sdof_prop, dt, time, dtime)
Six_DOF_Object *sdof_obj = NULL;
sdof_prop[SDOF_MASS] = 2.73e-3; /* flapper's submerged weight */
sdof_prop[SDOF_IXX] = 2161.86e-9; /* around the hinge */
sdof_prop[SDOF_IYY] = 367.96e-9;
sdof_prop[SDOF_IZZ] = 2471.27e-9;
real m= sdof_prop[SDOF_MASS];
real L= 0.024479 ;
sdof_prop[SDOF_LOAD_M_X] = 0 ;
sdof_prop[SDOF_LOAD_M_Y] = 0.0;
sdof_prop[SDOF_LOAD_M_Z] = 0.0;
real th_deg = theta * 180 * 7 / 22 ; /* valve opening angle, in degree */
sdof_obj = Get_SDOF_Object(DT_PU_NAME(dt));
/* Allocate_SDOF_Object must be called with the same name as the udf */
sdof_obj = Allocate_SDOF_Object(DT_PU_NAME(dt));
SDOFO_1DOF_R_P(sdof_obj) = TRUE; /*1DOF rotation*/
SDOFO_DIR(sdof_obj) = 1.0;
SDOFO_DIR(sdof_obj) = 0.0;
SDOFO_DIR(sdof_obj) = 0.0;
SDOFO_CENTER_ROT(sdof_obj) = 0.0;
SDOFO_CENTER_ROT(sdof_obj) = 0.0;
SDOFO_CENTER_ROT(sdof_obj) = 0.0;
SDOFO_CONS_P(sdof_obj) = TRUE; /* constrained motion */
SDOFO_LOC(sdof_obj) = 0.0;
SDOFO_MIN(sdof_obj) = -0.0349 ; /* min allowable angle */
SDOFO_MAX(sdof_obj) = 1.0471 ; /* max allowable angle */
SDOFO_INIT(sdof_obj) = SDOFO_LOC(sdof_obj);
SDOFO_LOC_N(sdof_obj) = SDOFO_LOC(sdof_obj);
But now I want to simulate the closure of the flapper, taking into account the friction at the flapper's hinge.
I tried to just assign the friction value to "sdof_prop[SDOF_LOAD_M_X]" ,but the flapper started to move backwards (opening) until the flow increases, which is not correct.
So I want to get the value of the hydrodynamic torque of the flapper, and compare it to the friction with some kind of "if statement" that may look like this:
real static_friction= 50;
real hydraulic_torque =??? ;
BUT THE PROBLEM IS :
I don't know the udf code that can get the actual value of the hydraulic_torque on the flapper to compare it to the friction value.
Your help is highly appreciated.
Thanks a lot in advance.
I am looking for the dataset where the users along with the vehicles are in motion. If the data set contains any social information that would help me alot.
I’m looking for native speakers of English who live in an English-speaking country and who don’t speak any Romance language (Spanish, Portuguese, Italian, French…).
My PhD research is in the field of language and cognition. More specifically, I’m looking into how speakers of different languages lexicalize motion events.
I’ve designed a video description task with 15 short video clips. The platform is mobile-friendly, and this survey will take no longer than 15 minutes of your time. And it’s pretty straightforward: the participants answer a few questions about themselves and then watch and describe what they see in the clips.
If meet the requirements and would like to take part, just follow the link below. https://survey.phonic.ai/624d5e0a269545d4b2d0e359
Thank you a lot for your help! Renan Ferreira Universidade Federal de Pelotas (Brazil)
My laboratory had purchased a set of IMU sensors (perception neuron 3) to capture the motion while performing certain motions. The software can output csv and bvh files. Is it possible to transform the 3 dimensional data to relative joint angle?
For example, to calculate the angle between hip and upper thigh, and thigh and lower leg while performing sitting down motion?
thank you in advance!
We are looking for tracking (6Dof) a rigid object over a large area (60mx60m) at atleast 50Hz update rate which could guarantee atleast 1mm resolution. We are considering Vicon, Qualisys, Motion Analysis, Simi, Coda motion MoCap systems. Which one of these suits best? Are there any other options?
I am interested in solving the dimensionless equations for a bubble motion in COMSOL Multiphysics. But do not how to enter the dimensionless equations for density, viscosity, Reynolds number, Weber number, and Froud number as given in the attached papers. Can anyone please help in this problem. I shall be very thankful.
In the superionic phase of a material like Cu2X and Ag2X where Ag+ or Cu+ are in motion in addition to the majority carriers of the material, electrons/holes.
I am simulating heaving and pitching motion of an airfoil using
1-translational motion of the outer domain of mesh
2- rotational motion of the inner circular domain of the airfoil wrt the outer transalting domain
My question is :
Which directions I am getting my forces , I get Fx and Fy. but do the axis rotate with the sliding mesh rotation or the fx and fy are always in the horizontal and vertical direction .
The mesh shape is shown for further demonstration.
Jerk is defined as the rate of change in acceleration. But I would like to know some practical applications of Jerk inorder to have better understanding. I kindly request to suggest me some examples.
I have been confused about the use of restraints in the molecular simulation. As far as I understand, the restraints are added in energy minimization so that only the solvent will optimize and it will orient correctly around our protein. The equilibration is considered the relaxation towards equilibrium of the system, but as the large motion of the protein before sampling is unwanted, the restraints are added again.
Yet, I by chance heard from a senior research that for dt=1fs nvt equilibration, we should not add constraints. (only added for 2fs)
I wonder whether 'constraint' here means 'restraint' or not. If it's restraint, then why should we removed it in case of shorter time steps?
Or maybe I have mistaken the definition/ purpose of the processes?
I am currently trying to create a contour plot(ABAQUS) of relative micromotions between two surfaces in contact. I have already developed a method for calculation of relative motions. However, I haven't been able to assign my obtained values to the nodes of the geometries that I am evaluating.
Until now, I have read that some people use subroutines to track paired nodes between two surfaces in contact and then they assign the obtained values in a form of a contour plot. Alternatively, developing a MATLAB code and creating a sort of scatter plot with the relative micromotions has also been discussed on some research works.
Nevertheless, I am trying to find a more friendly alternative that doesn't involve a developed code or the use of subroutines.
Creating a field variable from field output is not an option because the first task is to pair closest nodes between surfaces in contact, which is not possible using the operators available here.
If I need to explain myself better, I can provide more details. I will really appreciate any help on this matter.
Dear Honorable Colleagues,
I would like to initiate a discussion concerning the approach presenting active galaxies as stars at extra galactic scale. So, Quasar, Radio galaxy, Blasar and other AGN represent the same type of active galaxies seen at different ages and not from different view angles.
Adopting this idea, we can assume that: the quasar is similar to a T-Tauri star, the Blazar is similar to a neutron star, and the radiogalaxy is similar to an adult age star. If we take the complete chain of star evolution, we can also say that Hot, dust-obscured galaxy (hot DOG) is similar to a protostar, and HFLS3 galaxy is similar to a red giant.
If we take for example the radiogalaxy M87 (NGC 4486) considered as a star of adult age seen on extragalactic scale and we compare it to the Sun which is an adult star seen on the intragalactic scale, we note several common points between these two structures. these common points provide explanations for several phenomena. we cite as example.
1 / The random movement of stars in the nucleus of a radiogalaxy. This phenomenon can be considered as a nuclear reactions at extragalactic scale wich provids energy for the radiogalaxy. This phenomenon is similar to the random motion of the hydrogen protons in the core of adult age star wich is the source of the nuclear reactions.
2/ The supermassive black holes of active galaxies can be considered as stellar spots reproduced at a larger scale (extragalactic scale).
3/The presence of rings, loops and radio lobes in radiogalaxies, explain that the radio galaxies undergo eruptions and prominences at an extragalactic scale, similar to those that occur at intragalactic scale in adulthood stars .
4/ The fact that radio-galaxies are considered as a stars on the extragalactic scale, explains their presence in the center of subgroups of galaxies just like stars which are at the center of their planetary systems.
Other phenomena linked to other types of active galaxies (Quasar, Blazar...) find explanations in this approach.
For more detials, you can consult the link below, of the article titled " New model of unification of active galaxies and the different steps of their formation"
I want to do a dynamic analysis of the disc brake. The disc is rotating and brake pads are pushed onto it through variable pressure.
By revolving disc using Reference point, and using Dynamic implicit, Disc was exploding.
By using Predefined motion to give angular velocity to the disc; the disc is not revolving.
I am attaching the input file and screenshot of the model? Please help me in this regard.
Has anyone (in the community of rover path planning and rover motion estimation) used commercial wheeled mobile robots in their research?
I am an undergraduate student learning the basics of cell culture. I am able to successfully passage Caco-2 cells in T25 and T75 flasks grown in DMEMF12 10% FBS media with no issues. But, when I plate cells in a 12 well plate, I notice cells form a clump in the middle, mostly cells in suspension. In the edges cells are in an even monolayer (see attached picture).
How do I get to plate cells to form an even monolayer?
I seed 0.1 x 10^6 cells per well in 2 mL media. I predilute cells to the final concentration in a 50cc falcon prior to plating.
So far, I have tried decreasing pipette speed, seeding in a dropwise manner to avoid vortex effect, moving the plate in a clockwise or cross motion after seed, and tried plates from two different manufacturers. Are there any other suggestions on how to form an even monolayer?
Because I'm working on a different scenario, I'd like to make adjustments and assign different modules while working on a project. I'd like to know where the module may be found. Please assist me. Thanks.
Plate tectonics is a theory that states that plates on the Earth's surface move as rigid bodies. GPS is a system that is working independently on the theoretical motions of these theoretical plates, which means that the motions of plates must be visible when studied by passive GPS receivers (if you don't think so, tell us). Some studies work with the so called plate-fixed (net rotation) reference frames, such as e.g. NAD83, that use GPS data, but state that the frame is plate-fixed - no plate motion is visible. My question is: Is it possible that one creates a plate-fixed frame for GPS? If you think so, please, describe the process. I repeat that GPS does not care about the reason why the passive receiver changed its position - so how can you fix your data to a theoretical motion of a plate?
If I disregard the distinction between passive and active gravitational mass, then we generally associate two types of masses with an object, namely, inertial mass (mI) that appears in F=mIa and gravitational mass (mG) that appears in F=GmGM/r2 for the same object. While this is the theoretical explanation, these equations are meaningless writing unless we provide physical interpretations to those through experiments. Then comes the question that how we measure mI and mG of the same object whose motion is getting studied so as to verify the above equations. Therefore, the question arises whether the unit, in terms of which mI and mG will be expressed, itself is an inertial mass unit or a gravitational mass unit.
I shall be glad if anyone can explain this.
S-Curve Profile Without Motion Controller , used simple PLC to Create S Curve Motion Profile.
We all know Triangle and trapezoidal motion profile .it is simple formula. But when we talk about S Curve Motion profile then so much calculation come into Picture.
1. Why is needed
In triangular and Trapezoidal Motion profile starting Acceleration is high, jerk is present
And due to jerk material can not handle properly. So many industries require jerk free Motion
2. How to create S curve profile
If we have motion controller, used polynomial CAM. using this we can create motion profile as per our requirement.
3. so my question is can we create S Curve Motion Profile using Simple PLC?
I am also doing R&D on this. and also I got some success but it is not enough .so if anybody doing research on same i would like to know about it. That would be a big help.
i am ready to share my research with you.
I was performing a cfd analysis of laminar straight pipe flow in Ansys. simply, 1 m length pipe, inlet velocity is 1 m/s and outlet pressure is atmospheric . I found that at the fully developed region, the velocity at nearly 0.5 m from inlet , of course parabolic profile But the center line velocity is nearly 1.9 m/s . So I wanna know why ? why 1 m/s velocity get accelerated to 1.9m/s without any force. Of course fluid velocity also depends on position we call it convective acceleration and fluid get accelerated when area decreases But in straight pipe or two parallel layer , why acceleration happen ?
Sound boom happens when the speed of of a flying object exceeds that of the sound traveling in air. It's not easy to generate such a linear speed. However, this can be relatively easily generated by rotational motion. In other words, if we rotate an object, let's say a disk, fast enough, the speed of disk at the edge can easily be supersonic.
So here are my questions: Has anyone tried similar experiments? What happens when the speed at the edge of the disk exceeds that of sound?
i am working with FLUENT at the moment, to simulate a left ventricular contraction.
Normaly i would use different meshes of the LV at different times of a real contraction but unfortenatly i cant do this right now.
Here is my question, does anyone know how to set up something like a contraction. My basic idea is to just take the wall of the LV and move every point to the middle(or a specific point) of the LV at the same speed going reverse after time. Is this even possible to move the wall to a defined point?
I searched for different UDF's but couldnt find a answer for my problem.
I think i have to use the define_cg_motion macro or just a grid_motion macro to solve my problem.
Maybe anyone can help me with that problem.
If not, does someone own a list of possible commands for UDF's under c? I never used UDF's or worked with c so i dont know much about possible commands or tricks to set up the motion!
With best regarts
there are several methods for estimation of structural dynamic to predict the behaviour of the structure in motion. i am looking for a valid technique to analyze the movement of a bridge with single degree of freedom. i think most of the impact of the movement will be observed from the first mode shape of the structure when it subjected to any movement. i new in this research and want to explore this topic. if anyone can provide me some material regarding this topic i will be thankfull
I've simulated a pitching motion in Ansys Fluent with UDF, a CG_MOTION mocro.The domain is supposed to oscillate but it rotates,judging by animation. The motion is not a pitching one.
DEFINE_CG_MOTION(airfoil, dt, vel, omega, time, dtime)
/* reset velocities */
NV_S(vel, = , 0.0);
NV_S(omega, = , 0.0);
/* get the thread pointer for which this motion is defined */
t = DT_THREAD(dt);
/* compute change in velocity, i.e., dv = F * dt / mass
velocity update using explicit Euler formula */
dv = 1.89+0.75 * sin( 0.37 * dtime);
v_prev += dv;
Message("time = %f, x_vel = %f, force = %f\n", time, v_prev);
/* set x-component of velocity */
vel = v_prev;
what would be the problem?
Very interested in the therapeutic benefits of the rocking motion, such as rocking chairs, rocking a baby, self induced rocking motion, and how the vestibular system or the proprioceptive system is affected.
Assuming that no motion in the normal direction, how would you propose a system of hardware and interconnection as well as the control strategy that will drive the system?
The position,proper motion and parallax of a star (ra0,dec0,pmra,pmdec,parallax) are required.This information allows that we can now find the position at some other time(t) :
Here,t0 is the reference epoch and [x(t),y(t),z(t)] are the Cartesian barycentric Solar system coordinates in au of the earth on the ICRF at time t.
But I find the units of 'ra0' are deg, the units of 'pmra*(t-t0)' are mas,and the units of parallax*P(t) are mas*AU. 'mas' and 'mas*AU' cannot be added.
What should I do?
Is anyone already worked with MR image data set??? If so, Is there any model to remove the motion artifacts in the MR image data set if contains??? What should we do if we have an MR image with motion artifacts??? Please give me your suggestions if it is possible to remove artifacts once the scan is produced.
Thanks in advance,
Hi dear friends,
I want to simulation a whirl rotational motion and axial distance together in Ansys Fluent or Ansys CFX . For this work, Should I work on dynamic mesh and write UDF? or Is there other way?
In fact, I want to simulate a rotational spherical body in fluid. This body rotates and has a whirl rotational motion and axial displacement together. FSI(Fluid Structure Interaction) simulation can use in this work?
Thank, I am grateful that guide me.
There is a method to deblur images via Wiener filter:
I would like to deblur image from the video made by smartphone.
I need to estimate parameters for Wiener filter (Len, Theta, noise level).
How to do it?
I have a linear actuator of 1kN load capacity, 50mm linear travel, and M35X1mm thread at outer body. The spindle has M10 internal threads which is not through (closed end). I am having leakage from inside the actuator. Is it a way that I can transfer the linear motion with 1 micron precision?
Picture attached for current connections
Thank you in advance
Hi, I want to simulate the motion of a Spherical ball in an oil channel with COMSOL.this spherical ball must move the path in the oil with 5 (m/s) alongside the channel, and the water temperature changes In the radial direction.
I want to see the effect of spherical ball motion on the temperature in the pipe. and I can't fix the ball and give a velocity inlet in the channel entrance. I searched a lot but did not find anything similar.
Please guide me on which interfaces I should use. I really need your help ASAP or give me a Related tutorial file.
The problem is this: there is model of robot, created in Simscape. And knee of this robot is made of "pin-slot-joint", which allows one transnational and one rotational degree of freedom. In transnational motion, it is imposed the stiffness and damping factor, which gives influence also to rotational torque. My aim is to write optimization or control algorithm in such a way that this algorithm should provide such stiffness(in linear direction), which will reduce the rotational torque. By the way, rotational reference motion of knee is provided in advance(as input), and appropriate torque is computed inside of the joint by inverse dynamics. But to create such algorithm, I have no deep information about block dynamics, because block is provided by simscape, and the source code and other information is hidden. By having signals of input stiffness, input motion, and output torque, I need to optimize the torque. I will be truly grateful if you suggest me something. (I tried to obtain equation, by using my knowledge in mechanics, but there are lots of details are needed such as the mass of the joint actuator, it's radius, the length of the spring and etc. AND I HAVE NO THIS INFORMATION.) If you suggest me something, I will be truly grateful.
I am simulating the motion of sand in a narrow pipe. I tried to create the animation, and I keep the autosave of animation for particular time step in the fluent. The problem now after writing a file in the animation playback screen, it was difficult to visualize the motion of the particle, due to the high length to diameter ratio of the pipe (L=1m, D=0.003m). I wonder if there is any procedure to visualize the motion of particle in the saved animation file.
Other problem I faced in MPM, after I have created the periodicity in fluent, use the TUI command: define>b-c>m-z>m-p….., I am not abling to add the MPM model, using define>mod>add, because TUI still defined with Boundary condition. It is possible to switch off from periodic BC to add MPM model.
Thanks, in advance!
I am trying to make a panoramic image but my input images have motion and lens focus blur, if I apply some deblurring technique before images stitching, will this improve my final panorama quality.
I think we were all surprised at the first time we got to know quantum mechanics that the squared modulus of the wave function is the probability density of the existence of the particle?
The role of the complex numbers here is strange, but the question here is:
Is there an idea that is deeper and easier to understand, so that entering the squared modulus of the complex number becomes a mathematical result from this idea only in order to facilitate the calculations?
Do you share with me my astonishment and my question?
God willing, I think we can find something deeper and even simple, actually I put this reason in my paper:
The main idea of this paper is that the continuous trajectory of the particle can not exist, so the motion is a sequence of appearances and disappearances events in space and time, so the particle does always jump to move from one position to another.
So when the particle is in position p1 at time t1, where would it be in time t2?
In classical mechanics, the trajectory exists so the least action principle state that:
The path taken by the particle between times t1 and t2 is the one for which the action is stationary.
So what is the situation in quantum mechanics?
fortunately, we have a principle that is very close to the classical principle, but in this case, we didn't have any path, we have potential new positions, so in general, the particle has some preferred destinations based on a new quantum action principle named "alike action principle" that ensures the existence of physical harmony within our universe, like for example preventing the particle from easily reaching forbidden locations (guarded by fields of great forces).
Therefore, in general, this new constraint in motion could be valid at multiple positions at the same time, so in general, we have multiple acceptable positions at time t2.
Thus the probability of existence came up in our description of the movement in the quantum world.
We suppose that we have a preferred value of action that we call h (Plank constant), the new action principle called the "alike action principle" states:
"The preferred appearance destination position took by the particle at time t is the one for which all the remainders due to S/h (for all imaginary paths which lead to this destination) are stationary".
In other words, it is as having the same (or close to each other) remainder after dividing them by h.
For example, if we have two actions (for two paths) to one destination position, the natural function that verifies this principle is:
sin2((π/h)(S1 − S2)).
So after some steps of the calculation, we derive the relation between the probability density of the existence and the squared modulus of the wave function by deriving the path integral formulation of quantum mechanics, for more details please see the paper.
I'm using a slow motion video recorded using an iPhone 7+ to track something but would like to avoid recording a chronometer to know the time the process is taking. I need to measure about 10 seconds with an uncertainty of at most 0.1 s... Is this possible by just counting 2400 frames of my homemade video?
Thanks in advance
I am trying to solve a direct dynamic of equation of motion of Stewart platform using ODE45 in MATLAB. Even though I solved the inverse one simply, I had a problem with direct dynamic solution using ODE45 since the Inertia matrix and the Coriolis-Centrifugal terms are functions of states. Which means, inertia matrix and Coriolis-Centrifugal terms will be changed in each step of integrations and they are not specific matrices in all steps.
Also, I am using this article for my project:
I would be very happy if someone could help regarding this matter.
Working on an experimental setup where participants are asked to move around a small space. As a part of the overall measurement strategy, would like to take GSR measurements to determine potential stress when the distance between participants' bodies changes.
Looking for academic paper recommendations or any links to setups (outside of the FitBit world) that have successfully dealt with this measurement problem.
Sir Isaac Newton's gravitational theory is often viewed as belonging to the philosophical view of the cosmos of the solar system as being mechanical and mechanistic. Newton discovered that the large bodies which orbit about the Sun follow their respective trajectories in accordance with three laws of motion. What accounts for the fact that the planets have been observed to quicken or to retard their motion?
I have a Define_CG_Motion udf written in c where do I add it to my Ansys fluent project and does it need to be compiled before that?