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# Bearings - Science topic

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I am looking to design and further running simulations and analyse a low speed shaft of a typical wind turbine. In particular I am looking to design the shaft diameter and length and any other connection components such bearings, keys and so on, for a given torque and rotational speed requirement in a transmission system of a wind turbine. Do you recommend any good software to run FEA simulations for validation analysis purposes.
Any suggestions or comments, I will much appreciate.
Hello,
I use the Autodesk Inventor, but you could try Ansis
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What is the formula for the calculation of Reynold number for the thrust and Journal bearing.
In this formula, Re = (ρvD)/μ
1. What is the V(mean velocity) and D (characteristic dimension) for thrust and Journal bearing?
2. What is the limiting value of Reynolds number for the flow to be laminar or turbulent?
The formula for the calculation of Reynolds number (Re) for a fluid flow in a pipe or a bearing is:
Re = (ρvD)/μ
Where:
• ρ (rho) is the fluid density (kg/m^3)
• v is the fluid velocity (m/s)
• D is a characteristic length, such as the diameter of the pipe or the journal diameter in a bearing (m)
• μ (mu) is the fluid dynamic viscosity (Pa.s or N.s/m^2)
The Reynolds number is a dimensionless quantity that is used to determine the flow regime in a fluid flow system. It is used to classify the flow as laminar, transitional, or turbulent and is important for predicting the performance of the system and for designing appropriate components.
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Hello Everyone,
I have a subroutine for Elastomeric bearing. I want to use it for simulation in ABAQUS. For that, I need to define two noded UEL and assign them between two 3d Objects, as shown in the attached figure (UEL.PNG). As UEL can define only in the Input file, I am confused about how to assign the UEL between two objects. can anyone help with this? I have also attached the input file for reference.
Thank you
Hello dear friend, according to your question about the UEL subroutine, maybe this tutorial will be a good help for you.
According to the written headings, I think it covers what you need.
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I used deep groove ball bearing instead of journal bearing in scroll compressor, but it increases noise by 3-5 dB.
In journal bearing the cushioning effect is more due to thick layer of lubricant between metal surfaces, in ball bearing there is a thin layer of lubricant. Ball bearing also has more number of surfaces in contact according to number of balls in the loading zone compared to journal bearing, which increases the points of metal to metal contact in a single rotation. So it directly correlates to the noise. Hope this helps.
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The simple bridge simulation was performed in ABAQUS to evaluate the seismic response using Lead Rubber Bearings. The bearings were modeled using connector elements in Abaqus. I tried to enter the bilinear experimental data in Plastic behavior (Kinematic Hardening) half cycle data option in Abaqus. After simulation i obtained this irregular shape hysteresis. The hysteresis is constructed with reaction force and displacement at the Lead Rubber Bearing node.
Thank you
Share your complete details (Assembly, interaction loads and boundary condition) with me on my WA, https://wa.me/+923440907874.
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Dear folks,
I'm working on a design for a solar panel fixture for a capstone project. I have a panel weighing 20 lbs and with the frame, it's overall 35 lbs. The panel assembly will be mounted on a rod (48in long) using 6 routing clamps, and the rod has 2 bearings attached to the ends. I want to determine how much torque will I need to rotate this solar panel assembly, therefore using that to determine the size of the motor. And, to determine the radial and axial load to choose the right bearings. The speed will be 5rpm. Would be much appreciated if someone can provide support.
Sahib Bhardwaj Basically., To calculate motor horsepower, use the following formula: Horsepower (hp) = voltage x amperage x percentage efficiency x power factor x 1.73/746.
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Math problem We have a six-storey load-bearing structure with a floor area of ​​10X10=100sq.m with nine walls of cross-section 0.30X2.5m with 5X5m canvas Beams with a cross-section of 0.50X0.25m and slabs with a cross-section of 0.15m Height of each floor 3.00m If a very strong earthquake with a swing amplitude of 0.15m, a displacement of 0.30m and a full swing of 0.60m with a frequency of 2Hz strikes the structure, what will be the acceleration, shear base (inertia) and overturning moment of the construction and of each wall separately in order to juxtapose at the uppermost edge of the walls a greater moment of stability coming from the ground so that it does not topple over; Solution 1. Ground acceleration in ( g ) ( 1g=9.81m/sce2 ) a=( -(2*π*2)^2 * 0.15 ) / 9.81 a=3.14x2=6.28x2=12.56X12.56=157.754X0.15=23.6631/9.81=2.41g natural earthquake. Floor cubes Slab 15m3, beams 7.5m3, walls 15.87m3 Total cubic floor 38.37 m3 The six floors have 6X38.37= 230.22m3 Specific weight of reinforced concrete 2450 kg/m3 The 230.22 m3 of the bearing X the specific weight of the reinforced concrete 230.22X2450=564039kg or 564 tons of mass and the six floors together except the bases which are 50m3 Masonry 8 tons / floor The 6 floors 8X6 = 48 tons Floor covering weight 75kg/m2 X 100m2 the floor =7.5ton The six floors 6X7.5= 45ton Payload per floor 7.5ton The six floors 6X7.5= 45ton Total mass of six floors in ton = 702ton 2.Inertia force and shear base F=m.α 702tonX23.6631= 162908 kN Each of the 9 walls has a shear base of 9/162908= 18100 kN 3. Overturning moment of each wall separately The inertia on the six floors is 702ton One floor corresponds to inertia 6/702= 1117 kN Each wall of the 9 walls of the floor has an inertia of 1117/9=124kN What is the overturning moment on each wall of the six-story structure when the height of each floor is 3.00m? First we add all the heights (18+15+12+9+6+3) = 63 m and multiply them by 124 kN= 7812kN Then we divide 7812kN by the dimension of the width of the base of the wall which is 2.5 m and it comes out 7812kN by 2.5 = 3125 kN The overturning moment of the wall is 3125 kN Must Overturning Moments i.e. 124*(18+15+12+9+6+3) <(smaller) than the Stability Moment imposed by the force coming from the ground It follows that the stability moment coming from the ground must be greater of 3125 kN to prevent the wall from overturning and creating secondary moments in the cross-sections around the nodes. That is, Must Stability Moment > 3125 kN These moment forces must be received by the cross-sections around the nodes, or by my mechanism itself, completely freeing in this way the cross-sections around the nodes to generate counter-moments. Of course, due to the elastic deformation from bending, in reality the mechanism and the cross-sections around the nodes and the infills will receive the overturning moment of the wall together. The geotechnical study is the second serious calculation. Whether I get a deal is another factor. Here I reckon that the compaction of ground construction is a given. I am experimentally dealing with a compaction mechanism that converts vertical axial compressive and tensile forces into compressive forces and deflects them towards the borehole slopes.
The following RG link is also very useful:
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I want to model a 2d six-story steel moment frame containing the combination of base isolation and viscous damper in the base. I want to know which element is more relevant to my goal and also how I can use it in opensees.
I attached the picture of the model below.
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Hello everyone, I'm doing modal analysis of a rotorshaft with a disk. My model includes two bearings fixed between the shaft and two supports. I already know the stiffness matrix coefficients for my bearings so I want to know how to model the bearings.
I tried to create bearings with the "bearing body to body" tool in "connection" scoping the reference to the support face and the mobile to the shaft. What kind of boundary conditions do I have to add? I used a remote displacement condition for each bearing constraining rotation and translation about the Z axis (bearings are in X-Y plane) but I got the warning that remote displacements share one or more faces/edges and the model might be overconstrained. Why is it wrong? Am I not supposed to use a remote displacement for each bearing?
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I have to model a bearing in a large assembly instead of taking all the solid body into the analysis in ANSYS. Here I have roller bearing at a wheel location.
Is it possible to model using 1D element and give them a stiffness or any joints to be used to define the stiffness and other constrains
You can definitively use 1D elements.
What is usualy done is to create two nodes linked by a spring with the calculated stiffness of the bearing. Each node is linked by a "spider" to the corresponding surfaces of the parts that host the bearing.
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Access to firearms is a well documented risk factor for suicide. Regardless of why someone might have one or more of AR-15 or similar weapon, there's no disputing their inherent lethality. Irrespective of whether or not they are ever employed as a means of suicide, does their implicit lethality affect the nature/intensity of suicidal ideation and the likelihood that ready access to one may significantly increase the risk of using any firearm in a suicide attempt? Does this have any bearing on the suicidality manifested by perpetrators of mass shootings? If access to firearms creates a baseline capability for suicide, does access to potentially much more deadly firearms enhance that capability?
There's some credibility to the thought that access to any firearm has a positive correlation with suicide. Exposure to arms in a military, police, or other employment setting may well increase their use in suicides involving persons who have acquired familiarity with those weapons. As an incidental anecdote that might relate to familiarity with the method of suicide, a prominent toxicologist friend says that he sees nurses and doctors botch drug-induced suicide attempts frequently, but has never seen a veterinarian fail to kill themselves.
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My question is related to the dimensions of the dead layer of HPGe detectors for MCNP work. Is it normal that the upper dead layer formed is larger than the side dead layer? Or vice versa? Or are the two layers the same dimensions? Bearing in mind that the dimensions of the manufacturer specifications in the detector certificate that the upper and side lid are the same dimensions.????
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I would like to know the reasons for preferring Hansen's method over Vesic method, although in both methods the same range of answers are determined in most of the cases.
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I understand there will be exact multiple of fundamental frequency based bearing rotation with respect to fundamental, based on gear rotation with respect to fundamental. But what exactly means for multiples of bearing rotations, multiples of blade passes like 1x, 2x, 3x etc.,
Honestly, it depends...
It depends on the specific machinery and source mechanism.
It can be nonlinearities in the system (e.g., nonlinearities in linear drives like speakers), it can be (periodic) elements in the system (e.g. number of teeth in gears), it can be wear in components (which needs to be periodic on rotating parts, e.g. higher harmonics on railcar wheels - polygonalization), it can be impulsive behaviour triggered periodically by a rotating part (e.g. combustion impulses in internal combustion engines), it can be linearly moving parts that are not rotating (e.g. pistons), it can be some additional higher order torque components from inbalances, ...
The key point is that for all of these processes (except of some non-linearities that might generate subharmonics), you can only get integer multiples of the base period.
Nevertheless, it is important to mind the base period. For a 4-stroke engine, for example, this is 2 rotations, which is why you might also find "half orders" at internal combustion engines (and only full and half orders, no third or something...).
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For instance if one wants to assess effects of Malaria on pregnancy outcomes on pregnant mothers with Malaria infection.
Bearing in mind that they have to collect data from patient case notes of these pregnant mothers who had Malaria infection and were previously admitted and delivered their babies at a particular hospital in the past
I really appreciate the Question.
The d/ce between retrospective cohort(RC) and Cross sectional study(CSS) is
1. RC Assess the outcome whereas CSS asses both outcome and cause of the out come
2. RC is follow up study, CSS is snap shot/see the situation at a point in time
3. RC can help to formulate cause effect relationship but CSS cant.
4. RC have control group CSS dont
Eg1. If there were 2400 workers in a textile factory before 10 year, (at the begnning of 2012) and if u want to asses how the health status of those workers in the last 10 years look like, weather some die before 8/4/3/2/6 year or are healthy. This is dealt by retrospective cohort.
Eg.2 If u want to study the current prevalence of maleria, then the design is cross sectional. No control group you just prepared you, questionnaire go to area/study participants then ask.
Retrospective cohort, you will ask both exposed and non exposed groups
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I have a problem in my organization, which is that some department managers show a disagreement within them, and I have the desire to write a research that addresses this problem, which has aggravated. What is your opinion about choosing the title of the article, bearing in mind that the titles are modern and somewhat unpopular, can you help me, brothers and sisters, in that...
Regardless
Salam Abduljaleel Alramdhan
1. The value of personal, social and global coherence in conflict resolution.
This could lead to interventions using HeartMath tools and techniques
2. Distinguishing the relative value of universal, differential and unique management styles.
Focus group discussion could improve multicultural consciousness.
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I have been trying to generate a substructure in ABAQUS for a big diameter roller bearing. I have used two reference points, one each for inner and outer raceways to couple the inner and outer raceway surfaces. I have two steps in the analysis. The first step is Frequency followed by Substructure generation step. The analysis runs fine till the end of first step and calculates the eigen frequencies. When the second step starts, following error message appears.
" Element 439473 requires more than 2GB of memory for storage"
Element 439473 is just a point on the outer raceway and it is not used in any of the couplings. I have used continuum distributing couplings for coupling the reference points and the raceway surfaces. Following error also pops up after the element error.
***ERROR: An attempt to access admc buffer has failed. Any help would be truly appreciated.
Renganathan Sekar
I could solve the same problem by increasing the global seed size in Mesh Module, i.e. 20 to 22 (error: Element X (IDCOUP3P with Y nodes and Z dofs) requires more than 2GB of memory for storage.).
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What could be the effect of Waste Plastic irregular chips on the bearing capacity of compacted Soils? And If the Plastic is cut into regular shaped stirrups then how different will be the resulting improvement, if any?
The plastics can increase the California Bearing ratio of the soil. You can try that.
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Perhaps surgical techniques have changed and some are allowed but a good proportion are not allowed to weightbear. May I know the reasons or indications to keep a patient non-weightbearing? Noted a previous discussion on load bearing and sharing differences a few years back. Noted for IM Nailing, which is load sharing, patients are allowed to weight-bear early. Noted also that a dynamic hip screw is load bearing but weight bearing is allowed since stability is achieved. Thanks!
It is a bespoke scenario but we tend to let them weight bear. There are multiple factors to consider. Internal fixation is not a new science. The first half
of the twentieth century has provided us with ample documentation of the results of unstable internal fixation. Surgery has frequently proved to be the worst
form of treatment. It destroyed the soft tissue hinges, interfered with biological factors such as the blood supply and the periosteum, and was never sufficiently strong or stable to permit active mobilization of the limbs with partial loading. Supplemental external plaster fixation was often necessary. The emphasis
was on bone healing and not on soft tissue rehabilitation. Healing became evident when callus appeared. Unfortunately, unstable internal fixation was unpredictable
and uncertain, and it frequently resulted in delayed union, nonunion, or deformity. When union did occur, instead of signifying the end of treatment it merely signaled the beginning of a prolonged phase of rehabilitation designed to regain motion in the soft tissue envelope and in the stiff joints. The ravages
of this prolonged nonfunctional form of treatment were such that open reduction and internal fixation were looked upon as the last resort in the treatment of a fracture.
Neutralization plates or protection plates are used to protect the primary lag screw fixation. They conduct part or all of the forces from one fragment to
the other. In this way they protect the fracture fixation from the forces of bending shear and rotation
In metaphyseal areas the cortex is very thin, and if subjected to load it can fail. Such failures result in deformity and axial overload of the joint. Therefore, internal fixation in metaphyseal areas requires protection with plates that support the underlying cortex. These are referred to as buttress plates. Buttressing
may also be achieved with external fixation.
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Generally, in literature (from what I've read), to monitor conditions of mechanical rotating drivetrains connected to an electric motor are used accelerometers. Or in the case of short drivetrains also the current signals can be significant to detect anomalous torque load oscillations related to a mechanical fault. In the case of nonstationary conditions (not constant speed of the electric motor), the Computed Order Tracking (
Article Analysis of computed order tracking. Mech Syst Sig Proces
) is a technique that is able to extract Orders of the rotor speed in vibration signals even when the speed change over time. In that way, is possible to relate each component that rotates at a known, fixed rate with respect to the motor rotor, and detect unwanted vibrations.
Could I apply the same technique for electric signals? If I have an electric motor with a speed reducer attached with a damaged bearing running at varying speeds, once acquired the one-phase current signal and the rotor speed feedback, if I apply a resampling of that signal with respect to the angle (as in the Computed Order Tracking for vibration signals), would I be able to detect speed Orders that can be related to the defecting bearing? In literature, there are no papers that apply COT to electric signals (or at least I haven't found it), which is the reason? This technique would be ineffective? There are some resolution limits? Or depends on the fact that electric signals are rich in frequency content related to the supply and mechanical oscillations are too weak to be detected?
Certainly, electric signals to detect mechanical malfunction on the transmission contain weaker information. However, I was thinking, as a target of Condition Monitoring, on robotics systems (e.g. robotic arms). In such systems, is not so easy to add extra sensors, like accelerometers, while the current measurements are already available from the controller. Moreover, these systems use a relatively short drive train (each joint has its motor and a speed reducer). Thus, maybe, could be possible to detect mechanical and electrical malfunctions using only electric measurements.
I will continue studying and investigating in this direction.
Thank you also Bhupendra Desai for your information, I will have a look at your work.
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If we want to look at the universe we can not ignore the force that moves everything.
No one knows where this force that moves molecules and atoms comes from.
But we do know some physical properties of power.
Power = energy, which changes form, but is not lost.
Two equal and opposite forces, balance.
The force is diverted, that is, it changes direction
The force is broken down into components or multiplied by component forces, with the lever arm.
Power is everywhere but it is invisible and appears only from the effect it causes.
In the science of civil engineering there are static forces which are managed in order to achieve a balance of forces, and non-linear variables which are caused by the displacement of the ground in a seismic event.
When mass is stationary it is easier to calculate the forces of mass and contrast opposing forces to achieve equilibrium.
When an earthquake occurs, additional forces appear which are often three times the size of the static mass loads, because they are multiplied by the magnitude of the ground acceleration, the duration of the earthquake, and the height of the mass X its weight
These forces on the load-bearing structure of the building multiply, change their direction, and diffuse into all areas of the cross-sections of the structure, which are weak and can not react, creating equilibrium forces.
The result is that there is a breakage and collapse of the structure.
There are six solutions to balance and consume energy.
a) To increase the dynamics of materials without increasing their mass which is a factor of multiplication of intensities.
b) To convert the force of an earthquake from kinetic to thermal
c) To reduce the acceleration of the ground to be transferred to the construction using horizontal seismic insulation (bearings)
d) To make a rubber unbreakable bearing body from rubber or sponge.
And two other systems you do not know are ...
e) To put independent parts of the construction, to collide with each other, on elastic joints and in this way one part to neutralize the forces of the other.
g) To deflect the forces from the structure into the ground before they multiply through the lever mechanism and diffuse over the cross sections of the bearing body.
All but all of these systems that I mentioned contribute to the response of the construction to the seismic shifts and are concentrated in the anti-seismic design that I designed, for the first time in the world and is in this video.
Thanks for sharing the exciting information
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I am doing my project on journal bearing, it will be helpful suggest about the matlab code on solving reynolds equation by FDM.
Exact eqn
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In Taper Roller Bearing and Cylindrical Roller Bearing of different sizes, what is the process to test/check the noise and vibration in the assembly. If any standard process available please do share.
Luboš Smolík, Upon assembly of TRB on assembly line the vibration and noise testing is an essential part of process. To perform the testing I wanted to understand the standardized process of testing. Similarly understanding for CRB Assly.
I have tried to check the ISO Standards but the open copy of the same is not available.
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In this research, I am trying to replace the traditional bricks and concrete because these materials have much weight causes increasing the weight of the overall structure.
I want to replace the burnt clay bricks which use between Columns and beams with lightweight blocks. Bhavin G. Buddhdev
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The vibration sensor (e.g. accelerator) is commonly used to monitor the vibration signal of a bearing for condition monitoring and fault diagnosis. If there any Standard for bearing vibration signal monitoring?
Dear
J. Rafiee
Thank you very much for sharing, it is really helpful to me!
Regards,
Zhenyu
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A lot of deep learning algorithms (i.e. CNN, RNN, DBN, etc.) for bearing lifespan prediction have been reported. Each one has its respective pros and cons. But is there any technique that has been well applied in real industrial applications?
These papers might be an asset, have a look:
Kind Regards
Qamar Ul Islam
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The vibration caused by a bearing is usually used as a key parameter to evaluate the health and operating conditions of the bearing. To achieve this purpose, a threshold value of vibration signal to distinguish the healthy and abnormal bearing is often required. How to set/determine a threshold value of a bearing in a specific application?
Regards,
Zhenyu
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I am an undergraduate electrical engineering student researching on the application of motor current signature analysis for fault detection in three-phase induction motors. I plan to use LabView simulation tool. However I do not have a physical motor that I can use to create faults to it. Now My question is does LabView simulation tool provides an option for creating faults such as stator fault, rotor fault and bearing fault on the virtual motor? Your answers will be highly appreciated
Yes. The LabVIEW simulation tool can provide it.
The following paper may help you: "MOTOR CURRENT SIGNATURE ANALYSIS BASED FAULT DIAGNOSIS OF INDUCTION MOTOR" http://ijcns.com/pdf/ijpcscvol6no2-1.pdf
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Bearings are one of the key components in many industrial applications. Research on bearings has been going on for many years but has not stopped. What are the current and future research hotpots for bearings?
I know you ask for industrial applications but check the :-
e.g. (The hydrodynamic squeeze film lubrication of the ankle
joint)
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when the analysis is done by the Axisymmetry model, the out put of force vs displacement is obtained by the kN/rad. simply we multiply 2pi and get force in kN. in this case square footing (150x150mm) is half.
but when the same analysis is done the Plain stain model, the output is obtained kN/m. so which length of width is multiply to get force or how to get bearing capacity. use square footing 150x150
Note:
for rectangular footing if your conducting plane strain condition it will become strip footing?
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Generally CHO (DHFR -ve) cells on transfection with plasmid bearing DHFR gene + Gene of Interest and upon addition of MTX only thoose cells which take up plasmid (containing DHFR + Gene of Interest ) will survive others will die.
My doubt 1 is : Generally DHFR is involved in De novo synthesis of Nucleotides, then how the nucleotides are synthesized in CHO (DHFR -ve ) cells?
My doubt 2 is : CHO (DHFR -ve ) cells lack DHFR so they couldn't use De novo pathway for nucleotide syntheis but they can use salvage pathway, then after transfection with Plasmid (containing DHFR + Gene of Interest) all the cells will survive due to operation of salvage pathway, now how to distinguish between the transfected cells vs Un transfected cells.
Hello,
1. You are correct when assuming that DHFR-ve cells should not be viable. However, you can (and in fact have to) supplement the medium in which you grow DHFR-ve cells with hypoxanthine and thymidine, so that the cells can generate nucleotides via the salvage pathways. Therefore the otherwise non-viable DHFR-ve cells can be propagated in the supplemented medium.
2. Once you introduce the wild type DHFR in these cells, you dont need to add the supplements any more, in fact that is how you identify and subculture the cells that took up the DHFR expressing plasmid, as only those cells will survive that got transfected.
Although your cells now are able to synthetise nucleotides, you can add MTX, which will block the DHFR product which you have just introduced by transfection, unless the DHFR gene is expressed at a very high level (the DHFR protein must be present at high even amount that a low level of MTX can not block its function completely.). You can keep increasing the MTX concentration, therefore you will force an amplification phenomenon in which only those cells survive that express a very high level of DHFR - and the linked foreign gene....
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Bearings are one of the critical components in rotary machines such as motors, wind turbines, helicopters, automobiles, and gearboxes. Most of these machine failures are caused by bearing faults. Thus, being able to detect bearing faults and predict remaining useful life (RUL) can help to provide advance failure warnings, plan the maintenance schedule, and avoid catastrophic failures. What are the most common technologies for bearing fault detection and RUL prediction?
Eliseo Galli The bearings in big plants.
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Bearings are one of the critical components in rotary machines such as motors, wind turbines, helicopters, automobiles, and gearboxes. Most of these machine failures are caused by bearing faults. Thus, being able to detect bearing faults and predict remaining useful life (RUL) can help to provide advance failure warnings, plan the maintenance schedule, and avoid catastrophic failures. Based on this, what are the most prevalent methods for bearing degradation detection and remaining useful life prediction?
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When the proposed water-lubricated textured groove thrust bearing is under high speed, the initial cavitation number will increase, so the cavitation effect should be considered when modelling.
The previous research has established that cavitation obviously exists in the textured bearing, including thrust bearing under hydrodynamic lubrication and mechanical seals.
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the bearing capacity from hardening soil method and mohr-columb method is higher than theoretical method of Meyerhoff and Hansen method
Mohr-Coulomb model and Hardening soil model uses Mohr-Coulomb failure criterion and evaluates more or less the same failure load. Ultimate bearing capacity is failure load divided by the footing geometry.
Dear Ashish Juneja Sir even we have done this exercise in class, the evaluation of bearing capacity factors using FEM and matches well with Meyerhof solutions and is a little less than Terzhaghi's solution. Moreover, it is found that the FE solution is in between Terzhaghi's and Meyerhof's solutions.
Atish, evaluate the bearing capacity of footing using FEM and compare the FE solution with Terzhaghi's solutions too. Please refer to Table 2 in the attached paper. I hope it will be helpful.
Regards
Jitesh
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For the reaction between trifluroacetylacetone and primary amine, on which carbonyl group the C=N will form? The one that bearing methyl group or the other that bearing trifluroacetyl group?
Dear Nelly, this is in fact a very interesting technical question. I found a hint in the chemical literature that the carbonyl group bearingg the CF3 substituent is more reactive with primary amines and reacts first. In this context please have a look at the following potentially useful article:
Synthesis of Trifluoroacetylacetone Resin Through Schiff’s Base Reaction for Treatment of Cadmium-Contaminated Water
Unfortunately this article has not been posted as public full text on RG. However, two of the authors have RG profiles, so there is a good chance that you can request the full text directly from the authors. Please note that in this work the amine reagent was a polymer. Thus this reaction does note say much about simple Schiff base derivatives dervied from trifluoromethylacetylacetone. There is another relevant reference in which reactions of trifluoromethylacetylacetone with substituted anilines yielded heterocyclic compounds (quinolines):
Quinoline formation via a modified Combes reaction: examination of kinetics, substituent effects, and mechanistic pathways
In this context please also have a look at the respective Wikipedia entry on
Combes quinoline synthesis
This quinoline synthesis involves the reaction of 1,3-diketones with aniline derivatives.
I hope this helps. Good luck with your research and best wishes, Frank Edelmann
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I want to find the deflection of a beam which has a bearing support at the centre and two forces acting at the end of the beam. What kind of support can I approximate for the bearing support, for method of unit load.
For mechanical Engineering applications shafts supported on bearings act as beams. w=when short bearings or self aligning ball bearings are used it simulates simply supported end condition.
I copied maybe you can find more details here:
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Hello,
We want to choose specific bearing between all standards like SKF, KOYO, etc. Is there a book or excel file for finding it. For example we have ball bearing with this diameters 25X30X14. How we can find it between all standards?
Thanks for responding. You are right. It depends on some factors. However, we can use similar ball bearing. In reverse engineering, it is important to find desired ball bearing. We have to search in all standard's catalogs to find it. I want to know that is there any way to search it between all catalogs (not one by one).
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The Land developer in the south Asian countries performs mass rehandling of the earth to convert barren lands into housing socities. There are uncontrolled filling as deep as 30 ft. The filling material is mostly of Silty Clay type and it is in a relatively dry state. SPT N values are generally in the range of 4-10.
What could be the most effective and economical method to improve the bearing capacity of such fillings?
To improve the crushing of heavy loams and clays with soil mixer and milling cutter, it is recommended to introduce surfactant additives and lime when strengthening the soil with cement or liquid bitumen.
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i know the data is available under this website
but i am unable yo understand how to use in the coding?
Mohamed Ragab can you please provide with me the data and need for my research paper.
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Hye all;
Now I'am doing a simulation by using ANSYS FLUENT for the surface texture study of journal bearing. As you can see in the picture fluid area or journal bearing with surface texture...Unfortunately the result that i get which is maximum pressure of the fluid is lower compare with smooth/plain journal bearing. As i read in the journal, supposedly the result is higher for the surface texture of journal bearing as compare with plain bearing.. Any idea guys what types of surface texture i need to design, or the location or the parameter that i need to adjust in order to get the final maximum pressure value is higher as compared to plain journal bearing.Thanks
The texture height should be approximately of the same order as that of minimum film thickness in order to get improved tribodynamic performance.
You have mentioned in your query that, you are getting less maximum pressure with textured bearing. That means, your texture height is very large, which are effectively behaving just like an oil reservoir, but not as an flow restricting pressure dam.
Therefore, I would suggest you to try with smaller texture heights which are approximately of the same order as that of the minimum film thickness.
You can start with the simple spherical textures (which are also very easy to fabricate in real conditions), then proceed with changing the texture shape, position and aspect ratio.
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It is required for the stability analysis of bearing.
Thanks for suggesting the books.
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Large scale bearings especially that uses in wind turbines gearboxes exhibit transient loading that cause premature failure, I am working on estimating the percentage of bearing life reduction due to transient loading to predict the bearing life depending on the number of transient loading occurrence and their levels.
From what I know, AGMA has a standard for such wind loading, and the bearing constructors TIMKEN and SKF have prepared some material for the calculations you have asked for. In my section in ResearchGate you may find some material too. Good luck.
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First I would like to thank you all for the possible valuable suggestions. I have some confusion. I am doing roll bearing fault diagnosis using DWT and unsupervised machine learning algorithms. I am going to use the data set from FEMTO bearing repository but here is my confusion.
1. The accelerometer data was collected using 2 accelerometer arranged with perpendicular direction. so that I have dual direction accelerometer data. I am going to use DWT for signal pre-processing and feature extraction , it is feasible to take stastical features for both acceleration data for each frequency sub-bands?
2. The data repository was purposefully performed to determine the Remaining Useful Life (RUL) of bearing. so there is no training data for fault characteristic frequencies. How can I make training data set for each fault type associated with bearing anomalies. the link how the experiment was done is attached in case some one need it for test bench mark.
It's little late to answer a question asked in 2019, but here are my views.
1.it is feasible to take statistical features for both acceleration data for each frequency sub-bands?
Yes, it is feasible. The features extracted from both sensors can be fed to the learning algorithm. Check the accuracy. If it is satisfactory, then think of reducing number of features to reduce the computational complexity. Some basic signal processing algorithms might help to study if those two sensors at all carry different information.
You can also use sensor fusion techniques prior/after the learning algorithm.
2.How can I make training data set for each fault type associated with bearing anomalies?
No, you can not. Each dataset has specific purpose. Mainly, you will find diagnostic and prognostic datasets. eg. Diagnostic dataset : Case Western Reserve University.
So, if I understand correctly, for your requirements you have to look for diagnostic datasets.
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Analyzing a strip footing over granular soil having C= 2kPa & phi = 36 with density as 16 kN/m3, Mohr-Coulomb as soil model. Geogrid stiffness as 200 kN/m. Please suggest any changes.
You said that soil is granular. So, why did you consider cohesion for soil?
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Looking at the nmr spectrum of p-formamidophenol, the two aromatic protons bearing the OH and NH functional group appeared doublet each instead of singlet. Pls what could be responsible for this?
There should be 4 protons which appear like two pairs of doublets. The electron distribution of NH and OH are similar, leading to really closed singlet peaks.
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How do you think AI can be maximized in developing nations? bearing in mind some restrictive factors such as technology growth/
Developing countries often suffer from a lack of good teachers and schools. As a result, they frequently do not have very good academic standing and their people are less educated. With this lack of learning and cultivation comes a worse economy as well. The developing world needs to find a way to academically catch up with the developed world. Not only is it lacking in educational resources, but health care is a problem as well. Medical professionals are rarely available, especially in places further from the city. Individual appointments use up human resources fast, leaving others with no help. Even things like farming are getting to be more difficult. With the changing climate, farmers cannot use traditional farming cycles and predictions to determine the best time to plant their crops. Luckily, artificial intelligence is helping developing countries tackle some of their present challenges.
Regards,
Shafagat
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I had prepared 50ml of 0.5M Sulphuric acid and to that I added 20ml of 0.5M sulphuric acid containing 9 drops of 2M sodium hydroxide. I then leached the mixture for 15 minutes using a magnetic stirrer. In the same standard procedure I continued to increase the pH by adding more drops of sodium hydroxide that is from 9 to 34 and 50 drops.
thank you
follow
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How we can relate Unconfined Compressive Strength of Clay to it's allowable Bearing Capacity?
Strangely, you can use the Ultimate Bearing Capacity of soil at Failure, used by sauropod dinosaurs to determine the surface area of the bottom of their feet.
At soil failure, the Factor of safety is about 1.0 at about 5,000 pounds per square foot of horizontal surface area downward pressure. Sauropod foot prints thus determine the weight of the Sauropods in a reduced gravity environment of the geologic Past, which could be useful for construction projects on the Moon, or on Mars. On Earth, we tend to want a factor of safety of around 2.0 or higher, which reduces the surface pressure under foundations to 2500 PSF, or less.
The enemy of soils is water, and vibrations, and too high vertical, or horizontal loads. If you vibrate soils, they can flow down hill, or flow to reach a lower slope.
If you supersaturate soils, they can also flow downhill. The key is, design for the worst conditions expected. A wider foundation is generally safer than a narrow foundation, and the added cost is vastly less than the replacement cost of a failed structure.
This does not answer your question, but hopefully, it will get you to think about the importance of soil bearing capacity.
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I have a non linear wiener model (xk = x0 + θ_k*(t_k)^b+ σ B(t_k )). I have a sample of m RMS values collected for m intervals of time.
For getting these parameters (θ_k,b,σ,B(t_k )), can i perform partial differential of PDF and get values?
You can introduce joint distribution to pdf. Then differentiate with respect to the parameters.
Parameters that maximize the log likelihood function are the best then.
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Are all historical sources bearing an intellectual character?
Not all historical sources are of an intellectual nature, but some of them are political and religious
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Hye
Anyone here working or an expert in modeling of journal bearing with surface texture by using CFD ANSYS FLUENT?I have a question to ask related with this topic.Thanks again
Following
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If possible , then can the cantilever portion of the masonry buildings will be able to take the load of both partition wall and the slab??? (Soil bearing capacity is high). Suppose, cantilever length is 2 feet on every side and it has to be built on 2nd floor (already the building has been constructed 2 storeyed )
You have to simply analyze the structure. Calculate loading and bending moment and check for deflection. You need to design the structure accordingly.
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Hye
Anyone here working or an expert in modeling of journal bearing with surface texture by using CFD ANSYS FLUENT?I have a question to ask related with this topic.Thanks again
Reza Foroozani
ok noted and thanks..thanks again.
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I want to model a rotor. it has 2 bearing to connect to the earth. in the intraction module I set bushes. but i dont khow whats its boundary condition.
it can be equal condition which is omit displacement from 2 axis and just flexural displacement can vibrate for bearing location
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Is there any software that helps us in the calculating Safe bearing capacity of the soil, permissible loads on the foundation without actually going the same calculations again and again?
1. ALP99
2. PLAXIS 2D + 3D
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Hello everyone,
I am trying to generate a faulty acceleration signal with SIMULINK. The inner ring of the bearing is fixed to the shaft. The bearing has 17 rolling elements. I was thinking of creating a fault in the inner ring because it is attached to the shaft. My approach was to add 17 impulses per cycle to the original measured acceleration data in order to generate a faulty signal.
10.848 * f_wheel is the Ball Pass frequency of the inner ring.
Kind regards
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Hello everyone,
I am trying to implement an algorithm to detect possible damage at a bearing. In order to test my algorithm, it would be helpful to generate faulty bearing acceleration signals? Does anyone know, if a signal generator (whether in Matlab or Simulink) already exists?
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Hello, I am trying to use this mechanical vibration signature generator.
Ijaz Durrani
Thank you for providing some sources! As I read both articles, I understood that a calculation of the natural frequency is nearly impossible. I have to measure those. Is that correct?
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Hello, I am trying to write a program in Matlab to estimate the remaining useful life of a bearing without data of a previous failure. Do you think this is possible? I was thinking to use the amplitude of the ball pass frequency as an indicator but I am not sure how to do so.
Does someone know a paper (or even a Matlab program) which deals with this issue?
If your measured data are almost sine waves, have you done an FFT to determine frequency(s)?
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I am interested in finding RUL of bearing, which is currently in operation. I could find papers which uses run to failure datasets, which is not of my interest.
Can anyone suggest methods or papers to obtain rul for an incomplete dataset? If I use vibration data, wont it be different for different bearings?
To my experience, in case of incomplete dataset, the only reliable RUL prediction method is based on physical features and a pre- defined degradation model incorporated into a filtering framework, such as Kalman filtering or particle filtering.
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Hi, I am doing CFD analysis of journal and partial arc bearing. And I need to apply the following Reynolds boundary condition ( Pressure Boundary Condition ) by writing UDF.
P=Pa = 0 at Z=0 and Z=1 &
P=Pa = 0 at 0 =< thetha <= 360deg
Cavitation is allowed to occur at ambient pressure by setting all calculated negative pressure equal to zero throughout the iterative solution scheme. This implies that, the lubricant film ruptures and reforms when,
Kindly help
I am new in writing UDF for Ansys fluent
Antoni Artinov Thank you very much Sir
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want to make a fatigue simulation on some mechanical parts like Gears, Bearing, and gear housing. please assume 2 gears in contact.when they Are rotating under constant torque and velocity the stress in every node is unique and varies every time. I can define a signal for a node based on time stress (\Sigma (t)) of the node but I cannot do that for the millions of them. Is there any solution for this problem? I saw some tutorial videos but all of them using one or two signals and applying to all elements but I cannot do that. Stress in posision1 (X1(t),Y1(t),Z1(t)) do not change the same as posision2 (X2(t),Y2(t),Z2(t)). But in tutorial videos stress in po1 is a constant scale of po2 in every time and the scale stays constant. please help me to solve that I have many problems with that.
I recommend you use FRANC3D for Fatigue analysis. The stress analysis from ABAQUS or ANSYS can be exported to the mentioned software.
Hope it helps!
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I am actually wondering what is the range of oxidation potential of alkyl halides, especially species bearing an Iodine atom. I didn't find information in my book (organic electrochemistry by Ole Hammerich & Bernd Speiser). Thank you !
Dear Researchers,
Thank you for your answers. That helped me a lot in my study.
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Hello Everybody!
I am currently writing my master thesis in which I am trying to understand the stiffness values of tapered roller bearing. For this, I am have made the model simpler by using only a single segment of the TRB in Abaqus CAE.
During the loading stage, I am able to apply radial loading and find out the radial stiffness of the TRB segment but however, on the application of an axial load, the simulation fails. I am unable to find the problem as to why. Please find attached a picture showing the boundary conditions and the loading definition. The outer ring is constrained on the top and a kinematic coupling is used to constrain the inner surface of the inner raceway with RP2 and a radial load is applied on the same Reference point(RP2).
The load is also constrained in this picture with respect to the global y-axis for radial loads.
I have also tried to do that same by constraining the load in all directions except for the axial direction but the simulation still fails.
The step is set such that NLGEOM is on and the values for time step are 0.01, 1E-015, 1 with a time period of 1.
I have tried many different ways to get axial loading to work but was unsuccessful. It would be of great help to me if any if you could give me some ideas regarding this. Please feel free to ask if you require any further information.
Thank you!
You need to first understand how does it happens in reality. In reality the outer ring is pushed axially to preload the bearing and that is what you need to do in the simulation as well.
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bearing details:-
outer race outer dia-130mm
outer race inner dia-106mm
groove radius of outer race 12 mm
inner race outer dia 74 mm
inner race bore dia 50mm
wirth of bearing 30mm
Bearings are assembly of components and for any application you normally need the stiffness of the bearing as assembly(which depends hugely on bearing Rc and the bearing arrangement). Stiffness of Inner and Outer ring does not makes any sense (or may be I am wrong for your application?). would be great if you can clarify your question a bit better.
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I am trying to make Bearing Capacity Mapping of certain district and points are limited. But i want to cover whole district. If anyone have any idea please explain step by step.
When you are using tool IDW or kriging
after the input layer, z value click on environment
- environment setting window will open then select processing extent and select as your study area boundary
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The fulid inside the journal bearing should have minimum amount of thickness so that no metal to metal contact will exist.
Is there any references or books for this ?
Refer Raimondo and Boyd chart for same, you can refer my publication
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can any one provide material on journal bearing .
I want to manufacture the bearing and characterise that
Kindly do needful in this regard
Sliding contact bearings and journal bearings are same
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The words acquire, achievement, gain and profit have specific meaning. Acquire and achievement can be used closely bearing the similar meaning. But other two are different. How can we differentiate among them.
I think profit is the income derived from the regular business activity and Gain is the income derived on investment over a period of time
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Hello every one,
I am doing analysis of Bridge in which elastomeric bearing is modeled as link element between Deck and pier bent. Pier bent portal consist 2 pier and one cap beam on which elastomeric bearing are resting and on elastomeric bearing bridge deck is rest. I am doing non linear time history analysis.
Now (1 )due to elastomeric bearing, moment/forces are not transferred to pier hence bottom moment of pier has not reached Mp value and stresses in pier is very less (at least half of yield stress of Concrete)
(2) Joint Forces at link bottom has reached maximum level of forces and for bearing perfect elastoplastic force displacement curve has given as input of link
(3) Even if pier concrete has not reached at yield stress level CSI Bridge & SAP2000 showing hinges from IO to CP at various time steps.
Why does SAP 2000 Showing hinges in pier even if pier has not undergo plastic moment? Does it is due to yielding of Bearing
Hello,
It should be possible you add automatic hinges to your piers. Check it before any changes to your model.
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Dear colleagues,
As we know, there are so many equations in the direct method to determine the bearing capacity of soils. What is your best suggestion if we had a significant difference in results from those equations? Should we apply a conservative value (minimum) or use the average one? Thank you all.
Dear Sir,
There are many methods such as:
Plate load test and SPT methods are direct field methods to calculate the bearing capacity of the soils.
Regards
Qasim
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1:1 mineralogy is easily dispersed under saturated conditions. Is by add organic matter/amendment can stabilize these soil and increase soil bearing
J. C. Tarafdar yes but from paper 20-30% organic adequate for increase the aggregate but how it works in saturated water. the presence of water may disperse the aggregate soil due to the present H
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