Science topic
Stress - Science topic
For anybody interested in the causes, effects and management of stress
Questions related to Stress
In most common turbulence model studies, when considering Reynolds stresses the components of auto-correlation, <u'2>, <v'2>, <w'2> and components of cross-correlation <u'v'> are considered.
In the research studies of pipe or channel flow only <u'v'> component is taken for the investigation and given importance.
<u'w'> and <v'w'> is commonly not seen in studying parameters, why? is this solely due to magnitude negligibly of w'??
I am comparing a simple tensile stress and compressive stress results getting from Abaqus with my manual calculations. But, I could not able to find out where to check the value of tensile and compressive stresses in Abaqus/CAE.
Answer if anyone knows
can anybody know how i can get permission for use Bisht battery stress scale developed by Dr. Abha Rani Bisht?
Hello all, I am currently in the process of isolating stress granules from mammalian cells transfected with GFP-tagged FUS mutant.
I could see the stress granules clearly before and after cell lysis. However, I could not see stress granules after the centrifugation by fluorescence microscope.
I followed this protocol: https://www.sciencedirect.com/science/article/abs/pii/S1046202316303371?via%3Dihub
In brief:
(1) 2 plates (15 cm dish) of cells were scraped, spun down, and re-suspended in 400 µL of lysis buffer. Cells were lysed through sonication (2 seconds followed by 2 seconds break, 5 cycles) on ice.
Stress granule lysis buffer—50 mM Tris HCl pH 7.4, 100 mM Potassium acetate, 2 mM Magnesium acetate, 0.5 mM DTT, 50 μg/mL Heparin, 0.5% NP40, 1:5000 Antifoam B, 1 complete mini EDTA free protease inhibitor tablet 50/mL of lysis buffer. *Add RnaseIN 0.1 U/μL right before lysis.
(2) After lysis, spin at 1000g, 5 min at 4 °C to pellet cell debris. The supernatant was transferred to 1.5 mL microcentrifuge tube.
(3) The supernatant was spun with 18,000g, 20 min at 4 °C. The supernatant was discarded.
(4) The pellet was re-suspended in 400 µL of stress granule lysis buffer, spin 18,000g, 20 min at 4 °C. The supernatant was discarded.
(5) The pellet was re-suspended again with lower volume of lysis buffer (120 µL) and spun down with 850g, 2 min at 4 °C. Supernatant was transferred to a new 1.5 mL microcentrifuge tube. The supernatant represents the mammalian stress granule core enriched fraction.
I noticed the debris was not totally removed at step (2). Could it affect the yield of stress granules? Should I use higher speed or longer time of centrifugation to remove the debris? Or the centrifugation of step (3) and (4) need to be optimized?
Your expertise and guidance in this area would be greatly appreciated. Thank you in advance for your assistance.
Hi everyone,
I am looking for theoretical models that are related to appreciation. So far I have found the "stress as offence to self" theory to be very fitting. However, this is primarily applied in a work context. Now I am looking for studies that agree or disagree with the transfer of this model to the school context and alternative models from the school context about appreciation. The models should come from the field of psychology.
Many thanks in advance for any contributions and tips!
Dear colleagues,
I am reaching out to seek your guidance. I have recently finalized an article containing an empirical study focusing on the unique challenges faced by Ukrainian psychologists during the initial days of the war. Could you kindly recommend any journals that might be interested in publishing my work?
Attached is an abstract of the article for your reference.
Warm regards,
Anastasiia Kuntsevska
"Amidst the Storm: Ukrainian Psychologists' Early War Experiences" explores the multifaceted challenges faced by psychologists providing crisis care in Ukraine during the initial stages of the conflict. Through a comprehensive theoretical framework, this study investigates five key components: Unique Crisis Situation, Providing Help Despite Own Needs, Pro-Bono Assistance (Volunteering), Vicarious Trauma, and Learning During the War.
The research reveals the profound impact of the war on Ukrainian psychologists, who found themselves navigating unprecedented levels of trauma and stress. Psychologists reported high levels of apathy, trauma symptoms mirroring those of their clients, and difficulties in maintaining regular sleep patterns. Furthermore, engagement in pro bono assistance heightened emotional involvement and shared life difficulties with clients, while also posing challenges in managing their own well-being.
Despite these challenges, psychologists demonstrated remarkable resilience and dedication, adapting their approaches to meet the urgent needs of those affected by the conflict. The study emphasizes the importance of specialized training and resources to support psychologists in their vital role during times of crisis. Online seminars emerged as a valuable source of support, providing practical guidance and fostering professional growth.
Hello, I'm trying to use CES-D (for depression), GAD (for anxiety), and PSS (for stress) in the same survey, but they ask about different timeframes (in the past two weeks, one week, or month) in instructions, should I unify them or should I keep them as they are?
Thank you very much,
It is true that chlorophyll synthesis in plants decrease with increasing levels of stresses including salt stress, acid rain, air and soil pollution and drought stress. How do one explain the increases in Chl. a/b ratio under these conditions?
"Should there be a BS in 'Doctor of Psychotherapy' degree to meet the growing demand for mental health problems?? and if so, what might such a program entail?"
While "Doctor of Physiotherapy" is indeed a Bachelor of Science (BS) degree, there's no inherent reason why there couldn't be a "Doctor of Psychotherapy" degree. There are already doctoral-level degrees in psychology and counseling fields that prepare individuals for careers in psychotherapy, such as Doctor of Psychology (PsyD) and Doctor of Philosophy (PhD) in Clinical Psychology, Counseling Psychology, or related fields. However, such degrees mainly focus on the research side. The world is facing a pandemic of mental health issues, there is a dearth of mental health professionals who can use their counseling and therapy skills to treat patients with various mental illnesses.
These programs typically involve rigorous academic coursework, supervised clinical training, and research, preparing graduates to become licensed clinical psychologists or counselors who can provide psychotherapy services. So, a BS in Doctor of psychotherapy would solve this problem.
how can i get permission for use Bisht Battery stress scale by Dr. Abha Rani Bisht? ( For meassuring Academic stress of Adolescents
I have come across packages that specialize in fitting energy and forces, but none seem to include stress. I would greatly appreciate it if you could recommend packages that are capable of fitting all three parameters—force, energy, and stress—for neural network interatomic potentials.
For Zea mays up to the 4-leaf stage
For Phaseolus vulgaris up to the fourth trifoliate leaf stage
Every common source avoids the derivation, saying it to be too difficult. Where can i fiend volterra's original derivation? Knowing which mathematics would be necessary?
Kindly assist with my challenge. I used stress/atom commands in LAMMPS to calculate Von miss stress and hydrostatic stress of a silicon nanometric cutting. Unfortunately or fortunately I got hydrostatic stress of maximum -3GPa and 1GPa which is low compared to 11GPa - 14GPa for Si and diamond tool with 204241 atoms. Note, the hydrostatic stress is for tool atoms group. I attached the stress part of the script. If there is a need to attach the entire script, I will.
As a beginner in Abaqus, I am currently simulating metallic foam materials. Some literature uses Crushable Foam Hardening, while others only provide plastic strain and yield stress for hardening. I am curious whether plasticity's plastic behavior should be used for simulation, especially in 2D cases. Additionally, in articles where Crushable Foam is not mentioned, plastic strain is often used, particularly in 2D models. Furthermore, literature sometimes provides ultimate tensile stress, and I am unsure of its application, such as in failure criteria. Additionally, when attempting to export stress and strain xy plots from Abaqus, I sometimes experience crashes or freezing. Is there a solution to this issue, or should I use another software to read the ODB files?
Hi, I have been using *Initial Conditions, type=STRESS to import stresses. It worked well for C3D8R solid elements. However, I struggled to get it work for continuum shell elements SC8R.
I performed identical CAE operations but when using SC8R, the initial stresses imported were always zero. This is bizarre. Does it mean that *Initial Conditions, type=STRESS does not support continuum shell elements?
When I did the Geotextile simulation, I set the elastic modulus, Poisson's ratio and yield stress and plastic deformation for the material as in this article, and added the fracture strain with flexible damage, but the final result is that the ejector rod is jacked back and the geotextile is not broken. Besides the stress is so small that it does not reach the yield stress. These data were obtained by me through tensile tests.
A patient with desminopathy (mutation Thr341Pro DES in a heterozygous state) with the progression of the disease has a decrease in taste and smell, immunosuppression, and an increase in IgA in the blood.
Oddly enough, but all this is characteristic of infections, including viral ones. For example, it is known that if the hepatitis C virus is not treated, then death will occur in 20 years.
In the identified case of late onset desminopathy, muscle weakness manifests itself at the age of 30, and death occurs 20 years after the onset of the disease.
Could the desmin mutation in myofibrillar myopathy be caused by an infection?
Perhaps the infection contributes to the progression of desminopathy?
I am doing a comparison between different anisotropy models. Now, I am understanding the Barlat 1991 model. I understand the concept but I have some doubts about how to proceed to calculate the parameters. I would be very greatful if you could help me.
1- In the original paper by Barlat says that the a, b, c parameters can be obtained from Newton Raphson based on three uniaxial test in the anisotropy axes. I did a trial considering an effective stress of 350MPa. With 1, 2 and 3 referring to anisotropic axes the uniaxial yield stress in each direction are: s1 = 350, s2 = 350 and s3 = 345. Taking the definition of yield function gives by Barlat in Eq(22d) and using Mathematica with FindRoot to calculate a, b, and c parameters
FindRoot[{phi1 == 350, phi2 == 350,
phi3 == 350}, {{a, 1}, {b, 1}, {c, 1}}]
where, ph1 is the yield function with the only stress different from 0 is s1, phi2 with only s2 and phi3 with only s3.
So, the values of a, b, c are very high a = 250.001, b = 250.001, c = 199.111.
Newton Raphson should be a multivariable approach, right?
Obiously, I am doing something wrong, but I don't know what.
2- In the original paper by Barlat says that the other three parameters (f, g, h) are derived from the three shear yield stress. With the only non zero stress component sxy, for example, I am able to calculate h, but as in the previous point the value is so high.
3- The princiapl deviatoric stresses given by Barlat are comple, but other authors as in the thesis by Boxun WU "Application of Constitutive Equations based on Non-Associated Flow Rules for the Plastic Deformation of Anisotropic Sheet Metals" paragraph 4.2.3, principal deviatoric stress seem to be not complex. Are they equivalent to Barlat ones?
4- Other authors use minimize function to optimize the parameters, Which is the best way to construct the minimization function? I mean, the r values dependent of orientation are calculated by R_angle = -dε2/(dε3) = -dε2/(dε1+ dε2), where dε1 is the derivative of yield function respect s1, dε2 respect s2 and dε3 respect s3. The directional r values is a monster function (with 1, 2, 3 the anisotropic axes).
Anyway, how many terms are recommended to include into minimization function?
is it possible to calculate rb value (r value for equibiaxial stress)? If yes, how is it calculated? Is rb calculated with dε2/dε1 for an orientation of 45º respect rolling direction?
5- In Hill 1948 the width strain increment (the increment of strain at right angles to the direction of loading, alpha) is written as:
dεα+π2=dε1sin2α+dε2cos2α−dγ12sinαcosα,
However, in Barlat 1989 paper this relation is given by:
dεα+π2=dε1sin2α+dε2cos2α−2 dγ12sinαcosα
in the Barlat 1989 this term has a factor of 2 compared with Hill 1948. Why this difference in the shear strain term?
Thanks in advance
I need the relationship equations of yield stress and plastic strain for the input of abaqus. as i'm working on thermo mechanical response of steel structure.
What happens to all the overworked people in academia?
It does not matter that Ph.D. students are unable to cope with their financial problems.
Greetings and respect
I have done a non-linear analysis on a concrete water tower. It is important for me to know in which step and in which node the maximum of the first principal stress occurs.
Is there a way for the software, for example, for a 60-second analysis with a time step of 0.02, to automatically show the time of occurrence of the maximum of the first main stress, its location and its maximum value.
I am facing a problem with the simulation of the precast concrete beam with prestressing. Typically, a precast beam would be fabricated in the factory with prestressing tendons (precambering) to cater for the deflection due to long-span. That means the prestressing force resulted in bending moment in the precast beam portion only. It's not like post-tensioned beam where the prestressing is applied after the entire beam section has been formed. Therefore, to properly model the trapped in stress and strain in precast concrete beam, I need to model them in different stages.
What I am currently doing is to use the Interface_Springback keyword to write out the dynain file for the following analysis. This helps me to map over the deformed shape with the topping concrete mesh.
However, the dynain file only captures the initial solid and beam element stress. No strain would be copied over. So the concrete's compressive strain would be underestimated?
So I am wondering whether this is correct for the following analysis?
If I only copy over the initial stress and the deformed geometry, it will start with zero strain for all the elements.
Another option is I can copy over the initial stress of the precast concrete elements (with the beam elements for PT) but kept the initial geometry and then let the precast concrete elements deform under the initial stress. But that would cause the topping concrete elements to deform together which is not true.
I am currently doing PSD Analysis in fesafe, after taking the required files from Ansys i am unable to get the stress values in fesafe output window. Is there any option that i may have forgotten due to which i am facing this issue?
Hello,
I am measuring stress and strain on tissues in two different conditions and want to see the differences in the stress-strain curve. Since the nature of measurement introduces error during repeated measurement in both stress and strain there is both X and Y error for measurements and I obtain a graph like the one attached below. My question is what would be the correct statistical test to compare the two curves? and how can this be done using graphpad. One of the issue is that the X values are not same for both curves so ANOVA with one-on-one comparison becomes difficult as for the same X value I do not have corresponding Y values.
I’m relatively new to the field and have encountered a challenge while executing shearing operations between system components in Ansys Workbench. I’ve noticed a significant discrepancy in the results, specifically in the normal and Von Mises stress, when transitioning from a comprehensive model (solution) to a simpler submodel (setup).
The only data transferred was the displacement field, which was consistent with the one produced by the global structure results (solution). However, this consistency was not observed in the results for normal and Von Mises stress.
Could this issue be attributed to the geometrical differences between the structures? Or are there additional conditions that need to be adjusted to rectify this discrepancy?
I would appreciate any insights or suggestions.
Thank you.
In have been doing an NMDS of plancton, fish and aquatic macroinvertebrate abundances with 7 environmental variables in PAST. But when the analysis is complete the stress value it gives me is 0, is it normal or is there something I am not doing right?
in the unreinforced concrete model, after reaching the maximum force, it should experience failure and no increase in force occurs. Can anyone help?
Music therapy, where a person feels calm when they are stressed, is when they listen to a particular song they relate to.
I'm trying to use CDP model but i only have ultimate strength of concrete how should i create stress strain data sheet
I have a model of a shell plate with several layers of composite materials, designed using CQUAD elements. As part of the static analysis of the model, Nastran provides me with the stress and strain in the middle plane of each layer. Is it possible to obtain the stress and strain in the top and bottom planes of each layer by modifying the .bdf file? I do not wish to use Patran for post-processing.
Education is imparting stress to each and every individual. There is heavy competition and all are striving to reach the limit. There are plenty of things to do and there is nothing in specific. Everything is made important and mandatory. There is also no special focus on a particular thing and hence becoming sensitive in approach or dealing things. Do you think that in this current scenario, education is good? What is your feeling?
Dear all,
I am maintaining sheep iPSCs, however after few passages sometimes they start making mysterious projection which are not characteristic of these iPSC. I am following best practices to minimize any kind of stress to these cells (light, temperature difference, changing media daily). These happens to my cells only, as other team members grow cells in good state. These are earlier in passage (p18), doesn't happen every time. However, quite frequent, I discard these cells and start over. Need your suggestions and explanation for this weird phenomena. I have attached pictures at 4x, 10x and 20x.
Thanks in advance for your time
Generally in the stress vs strain curve of polycrystalline metals and their alloys, we tend to observe an initial elastic deformation followed by plastic deformation marked with strain hardening. This strain hardening follows a parabolic behavior. A linear strain hardening is also observed in the second zone of single crystal stress vs strain behavior. How come a linear strain hardening behavior in polycrystals??
Sincere regards
Subha Sanket
IIT Kanpur
I'm working on p-norm topology optimization in plane stress using a MATLAB code adapted from the article An efficient 146-line 3D sensitivity analysis code of stress-based topology optimization" by Hao Deng, Praveen S. Vulimiri and Albert C.To. I've noticed small sensitivity values (e.g., 4.54e-05, -7.30e-09) with a stress norm parameter (p) of 5. Are such values typical in this context, and should negative sensitivity values be expected? The relevant codes are attached.
Your experiences and recommendations would be greatly appreciated.
Thanks!
Who else notices a contrast in Hegelian and Marxist politics? How? Why? My answer: Hegel stressed more obedience while Marx clearly did not.
We are a group of researchers who are affiliated with different academic institutions in Palestine, Jordan, India, Malaysia, and Indonesia; interested in studying HRQOL in the context of/correlation with perceived stress among medical students.
Please, if interested contact us on (only on):
What are the 11 dimensions of resilience and difference between stress resistance and resilience?
Hello,
I am performing a monotonic pushover simulation on a steel shear wall configuration. The instances (columns, sheet, and beams) are modeled using S4R elements with a relatively fine quad mesh.Surface-to-surface contact and cartesian connectors are used to model the contact. The default value of automatic stabilization is used. The configuration is pinned at the base and the loading is defined using a monotonic displacement controlled protocol (1 mm/sec for 200 seconds). Initial time increment is set as 0.001 with a max of 0.1. When the material is modeled as perfectly plastic, the analysis runs fine and the results, as far as deformed shape and stress fields go, make perfect sense. However when plastic strain/stress values are introduced (true stress and true strain, based from experiments) the analysis reaches a point (about 50%) where the time step size cuts back to a very small value (1.9e-6). No warnings are reported and the analysis has been running for about 12 hours now without aborting.
Am I missing something? I was under the impression that adding a slope to perfectly plastic material in ABAQUS actually helps with convergence issues. I have attached the input file, any help is greatly appreciated.
Thanks!
Why biodiversity is important to the ecosystem and how biodiversity can help maintain a viable ecosystem for resilience to stress?
I have Force-Displacement values of a tensile test that undergoes uniaxial loading. Please find attached the stress strain curve of the loading.
Sigma1 denotes the Equivalent stress of the element at current time increment and Sigma0 denotes Peak equivalent stress of the element reached at the end of the loading stage. I need to calculate a stress ratio Sigma1/Sigma0 at each time increment.
In order to calculate the stress ratio, the time increment of the peak stress has to be reached after which the field variables (of USDFLD) in the previous time increments has to be modified to calculate the stress ratio. This stress ratio has to be applied to the material model of the same simulation.
Is it possible/recommended to achieve this using USDFLD? Or is there a better alternative in ABAQUS?
I have done parametric study in Ansys Material Designer by varying the volume fraction of carbon fiber. Now I would to have a look at stress distribution in the RVE for each design point. How can I view?
Thank you.
My dear teachers
Can you please guide me to find a scale to measure stress level that is relevant for patients with high blood pressure, except (the Perceived Stress Scale or DASS 21)
Dear all,
I am trying to simulate the fatigue crack of aluminum in ABAQUS. I can't find the maximum principal stress of Al and other data that I showed in the attached file. Is there any solution?
#abaqus #fatigue_crack #maximum_principal_stress
I want to ask about the compressive strength results of concrete cube using APDL Ansys: my question is: The total compressive test is it the von mises stress or the component stress in y - direction.
other question what does the minuses (-) value stress means.
the effect of massage on the stress and anxiety of athletes.
How does a species adapt to changes in the environment and what environment related stresses hasten evolution in a species?
Hello there, hope you are fine. I need a research topic as my research is starting in a couple of weeks. I want to do research that will be unique and hasn't been done by anyone else yet on a crop that is compatible with to season nowadays and must be under some kind of stress. please help me.
I am using large deformation formulation in my simulations and I am wondering if Von Mises equivalent stress is employed for Cauchy stress or it can also be used for 2nd Piola stress tensor. Related references would be beneficial. Thanks
health education program covering stress, depression, anxiety, and positive coping strategies, that can use intervention to improve mental health among adolescent ?
I am currently researching the stress physiology of photosynthesis. I have previously worked with hydroponic systems using heavy metals at concentrations around tens of microMolars. Now, I would like to extend my research to potted plants and induce cadmium (Cd) stress. However, I understand that I cannot use the same concentration of heavy metal solution in potted plants due to various factors related to the substrate, which might prevent me from observing a significant stress effect. What would be the most appropriate concentration or solution to effectively induce stress in potted plants?
Hello everyone i'm a student currently looking at intermittent palatable food exposure. I want to start a female rat cohort and preferably single-housed so i can measure their individual food intake. Our previous female group was really stressed. is there a method available allowing me to measure their individual food intake while minimising their stress? Thank you!
How long we have to trypsinize A549 Cell as well as Beas2b cell line?? is it due to to fault during cryopreservation ?
How biodiversity can help maintain a viable ecosystem for resilience to stress and difference between ecosystem resilience and ecosystem resistance?
Hollomon and Swift flow stress models are popularly used to describe the true stress-true strain relationship in the strain-hardening range from yielding point(yield strength) to necking point(tensile strength), each of which are defined as follows:
Hollomon : σ=K(ε)n
Swift : σ=K(ε0+ε)n
Is epsilon(ε) here true total strain or true plastic strain?
What is your opinion?
I am also looking for volunteers to complete my survey. The survey is about: The Impact of Artificial Intelligence on Academic Productivity and will take about 5 minutes to complete. Your responses will be anonymous and used for research purposes only.
If you are interested in volunteering, please click on the link below to access the survey.
Thank you for your time and consideration.
Dear all,
I am trying to model the contact between the BEAM elements in my model for collapse analysis. I start off with a simple analysis where I have modelled a beam hitting a column, as shown in the picture below. The beam experienced some stress as it approached the column however no stress was experienced by the column. At the end of the analysis, the beam just passed through the column. How is this possible? Am I doing something wrong?
Any help will be greatly appreciated! Many thanks!
Kind regards,
HEng
i want to study impact test of adhesively SLJ using abaqus, but
i couldnt know how to define adhesive material and interaction properties,
i get information about adhesive properties these below;
E(MPa) 1520
G (MPa) 565
σu (MPa) 46.93
τu (MPa) 46.86
GIC (N/mm) 4.05
GIIC (N/mm) 9.77
thickness: 0.2mm
1-is it sufficient?
2-is it correct way to analyze it, edit material> Maxs damage + Elastic>traction-->entering values.
3-if it is true, program wants from me this values for maxs damage;--> nominal stress normal-only and first and second direction
how can i put this values? How can i calculate or find? any suggestions
4- should i also do interaction properties-->contact-->cohesive properties , if yes, how can i calculate or find the Kss,Ktt,Knn values
5- Lastly there are limited information about repeated impact test for this topic on internet, how can analyze the repeated test, like, impact to deformed SLJ joint (including its previous stress values)
if someone helps, i would really appreciated..
In the context of an animal experiment, what are the common methods used to induce stress, and how do researchers assess the physiological and behavioral responses of animals to these stressors?
Hi all! I designed a Wellness Program for Nurses as my QI project to evaluate the impact of this intervention on the participant's stress levels (using Perceived Stress Scale). I am planning to conduct a pre-intervention and post-intervention survey. The participants will be the same (same department) in the pre-post survey. I originally had planned a Paired T-test as my statistical analysis, and de-identify using pseudonyms.
But I was advised not to match my respondents due to ethical issues, make the survey completely anonymous, and we can aggregate the data of pre-post tests, like how we would do an independent t-test. (My project is under non-human research so won't need IRB approval.)
Is the independent t-test even valid for my design? Any suggestions on how to approach this? Any other stats I can use if my pre-post for the same group are completely anonymous or unmatched?
hello,
is there a solution or code for exporting the min and max values of stress and strain and displacement from multiple .odb files saved in the directory and exporting data in an Excel file?
Hi all,
I am thinking of collecting data on stress for a leadership study I am doing. For HRV, I was thinking to use wearable devices. But I am also thinking of cortisol strips. Any other good ways. Any good psychometric scales for stress that you have used in your research and can recommend?
Im modelling a clamped-clamped beam with a uniform load. In order to see when collapse occur Im increasing the load to see when Abaqus is aborting, this is working except that the collapse load is overestimated by 700-800 kN in this case. I have calibrated the time increment and the mesh so it should not be regarded to this.
Then I looked at the stress distribution in the cross-section and found out that the stress is actually increasing above the yielding point at the support (see picture), so wonder if there is a correlation here? I mean if the beam obtain more stress after the plastic limit then the collapse will be overestimated right? :)
So how to I tell Abaqus not to go over 355 MPa which is the yield stress.
Adrenal stress is the modern misunderstood syndrome that affects most of us to varying degrees. Stress, whether physical, emotional or environmental, can stimulate a cascade of hormone production by the adrenals which includes adrenaline, noradrenaline and cortisol.
Adrenaline is the most famous of the three stress hormones and acts like an ‘upper’ helping to enhance the function of all our body’s systems in order to meet the demands of stress such as circulation. Noradrenaline is the body’s modulating hormone working to keep us revved up without causing stress to our body’s systems including the heart. Cortisol is the body’s ‘downer’ working to bring the body back into its normal healthy state when it has been revved up for too long or once the stressor has gone away.
Let's say I have the values of my material properties (e.g. UTS, Yield Strength, Young's modulus) after conducting a tensile test, and then I would proceed to conduct a fatigue test to investigate on the fatigue strength.
Hence, I wonder what stress should I start with to conduct the fatigue test?
Hi there, I would like to publish my undergraduate research in relation to Attention Restoration Theory and Stress Reduction Theory. Where is the best place to get this published?
I am modeling a concrete cylinder compression test (see attached). Loading is applied along z direction, and I am checking the sigma_33 stresses. I am having maximum signma_33 at the element centroid around 78 MPa (see attached graph). I don't get it why it is higher than the ultimate concrete strength of concrete (58 MPa).
Which stress does ABAQUS consider to check yielding and damage for concrete material?
effecting the stress on evapotranspiration by salt and deficit water
What is the relationship between faculty interactions, sense of belonging and academic stress?
Below you can find equetion which express flow curve which describes the plastic deformation behavior of a material in a uniaxial tensile (or compression) test. I looking for books, articles which gives me information how values of C and n depends on geometry (eg. diamater and wallthicknes of drawn tube) as well as initial mechanical properties, before material work hardening. Do wires and rods of the same material but with different dimensions have a different form of the flow-curve, or does it depend only on the initial properties of the material?
Hi everyone,
I recently ran some compression tests for hydrogels and received data in form of force (N) and displacement (mm). I am new to this area so would really appreciate your help here. For starters, I know that I need to convert it into Stress (pascal) vs Strain data (mm/mm). However I am really confused how I need to represent my strain. I have converted the force into stress by dividing with area of upper plate but with strain I am lost between engineering strain ((Io-I)/I) and true strain (Ln(I/Io)). Would be obliged if you can kindly shed some light into it.
Thanks in advance
The prestress is much larger than its elastic stress limit, which means if I add this stress to the material, the material will endure plastic strain immediately.
Should I only input the elastic stress and change its shape or input all stress?
Hello Friends,
I wanted to know how to access the value of a variable for all integration point inside UMAT.
We can get access variables in integration points from .odb file in UMAT. We can also write a .dat or .txt file inside UMAT which gives us all the values from integration points. but it is a very slow process.
I wanted to for example have the access to Zigma11 for all integration points inside UMAT so I can save them as state variables. For example, C3D8 has 8 integration points, so I want to get 8 values for zigma11 in umat to save them as state variables 1 to 8 which gets updated at each increment.
If you can change your lifestyle/behaviour, how soon can these changes be detected in the epigenome? How long (estimate) would this change be detected in the majority of cells? Can this change also be detected in gametes? Will these changes be passed onto offspring?
By behaviour I mean things like having a good diet, working in less stressful environment, stopping smoking or even more taking more exercize.
Dementia affects several millions of people across the world. There are various types of dementia and Alzheimer’s disease is the most common type. This disease that is yet to have a cure affects several millions of families in several different ways.
Dementia is a global crisis, perhaps we can call it the dementia pandemic! Dementia is everyone's problem and as a result, we must take the responsibility to look after ourselves. One of the easiest ways to support people living with dementia and their caregivers is to be aware of this disease and by so doing we probably can become a little bit more compassionate and dementia-friendly.
Most people living with dementia receive care from their immediate family members or friends and neighbours. This makes informal caregivers become isolated. They become what we call the invisible patients. Most people who provide informal dementia care are female caregivers mainly spouses, female adult children, family members, friends, and neighbours.
Dementia caregivers suffer equally as they are mostly available to provide the required care for their family members who are living with dementia. Informal caregivers suffer from several conditions such as physical and psychological challenges,
loss of job/livelihoods = financial problems, and loss of social life such as their hobbies. Among other challenges, informal caregivers suffer from stress, anxiety, and depression.
How dementia-friendly are you and how dementia-friendly are your localities?
I am working with veroe6 for a while and every time I receive a new healthy flask one or two passages and cells become stressed. Please any one will give help why this happens and how to prevent this and if there is away I can regain the cells healthy without replacing my current stock.
I am using DMEM 10 % horse serum
5 ml ofglutamx and 5ml non essential amino acid
0.08x porcine trypsin and 0.08x versine
Cells dissociation in 4 mnits
Centrifuge 750 rpm 5min
Split ratio 1.3
Researchers and materials practitioners often come across the stress-strain diagram, which is a popular tool used to select materials based on their mechanical properties.
While the diagram is a useful resource for many applications, it is an issue that it is 𝐧𝐨𝐭 𝐜𝐨𝐫𝐫𝐞𝐜𝐭 to use the stress – strain diagram for fracture analysis - a fatal beginner's mistake.
The reason behind can be understood in our today’s illustration below!
Let me know the comments below.
Reservoir Engineering: Coal Seam
1. Since, gas is primarily stored by adsorption into the coal as a function of pressure @ which the gas gets adsorbed, can we replicate the scenario, whereby ‘the amount of gas adsorbed per unit increase in pressure remain decreasing with increasing sorption pressure’ @ laboratory-scale using experimental investigations?
2. Feasible to achieve ‘equivalent sorption pressure’ @ laboratory-scale, where the water pressure of the water-saturated coal seam remain exceeding the pressure @ which all gas becomes adsorbed into coal-solids or into solution gas?
3. With a relatively low bulk permeability of coal (around 1 md); and, with a ready desorption from solid; what should be the closest spacing of cleats (10 mm or 100 mm), whereby, the dominant mode of fluid transport in a coal seam could be treated as to be Darcy flow (as against with a relatively less fractured structure; and, with slower desorption from solid, where the rate is controlled by diffusive movement)?
If not, how exactly to deduce an average cleat spacing and permeability into which the solid blocks could be considered to diffuse?
4. With Darcian flow being the prime importance in the movement of gas within the coal, can we reproduce the scenario, where the permeability could be strongly directional-controlled by predominant cleat sets @ lab-scale?
5. What is the physical basis by which we decide the permeability of a given cleat structure within coal remains to be dictated either by
(a) phase relative permeability effects, whereby the degree of saturation would affect the gas and water relative permeabilities of the reservoir? or by
(b) changes in the effective stress (total stress minus the seam fluid pressure) within the seams?
Feasible to capture the way the effective stress tends to close the cleats; and the way, it tends to reduce the permeability within coal @ lab-scale?
Under what circumstances, the permeability would remain related to effective normal stress across the cleats?
Any idea about how exactly the gas gets traveled through the core specimen?
6. Feasible to capture all the required 3 factors that influence the effective stress @ lab-scale?
(a) initial-stress (given the weak and jointed nature of coal, while it also remains to be directional);
(b) fluid pressure changes; &
(c) shrinkage/expansion characteristics of coal matrix
(which remains related to the equivalent sorption pressure in the seam).
Feasible to secure stress patterns by ML/AI - from stress measurements in the rock surrounding the seam – deduced as a function of
(a) stress caused by gravitational effects, where the overburden stress and the associated lateral stress getting developed under conditions of no lateral strain; and
(b) horizontal stresses, which gets induced by tectonic forces (and, which should remain proportional to the moduli of the rocks, while the respective horizontal strains remain approximately equal)?
Reservoir Geomechanics
1. Why do we need to forecast
both the ‘stress-regimes’ and ‘pore-pressure distribution’
prior to drilling?
2. Feasible to capture
the evolution of
‘restructuring of pore-geometry’
as the pore-pressure regime
evolves with hydrocarbon production?
3. When does the difference between
solid and fluid expansion to rock stresses and
fluid diffusion
become critical?
4. Under what circumstances,
do we have a significant deviation -
from the assumption that
“mechanical compaction is solely driven
by the vertical effective stress
exerted by the over-burden”?
5. Under what circumstances,
‘pore-pressure’ cannot be considered
to be
the ‘average oil-water phase pressure’?
6. Under what circumstances,
‘the reservoir rock saturated with oil and water’
tends to have
‘a “significant” elastic deformation’; and in turn,
ruling out the assumption that
“the reservoir rock remains to be in dynamic equilibrium state”?
7. As against the ‘reduction in reservoir permeability’
resulting from ‘rock compaction’ -
upon ‘increase in net stress’
(resulting from the changes in the initial stress state – associated with the reduction of pore pressure during reservoir production),
how frequently do we encounter the cases,
where the ‘increase in net stress’ lead to
‘the enhancement in permeability’
associated with the ‘stress paths’?
8. Which ONE of the following data
remains relatively easier
to secure from a real field scenario?
(a) permeability hysteresis behavior;
(b) stress-dependent permeability; and
(c) strain-dependent permeability (from strain-dependent porosity as a function of deformation & pore-pressure).
9. How do we decide whether
a particular reservoir
needs to be characterized either by using
(a) poro-elasticity theory; or, by using
(b) poro-elasto-plasticity theory?
Do we have enough data with us?
If not, what is the very purpose of solving
the governing equations of ‘reservoir’ and ‘rock deformations’ “simultaneously”
“at every time step” (fully coupled) –
that remains unconditionally stable?
Hello,
I'm using UMATHT user subroutine in Abaqus (FEA) and I'm trying to see what hardening curve it applies. I introduce the hardening exponent, the yield stress and young modulus in the material module and there is some formulation. However, I'm unable to check the formulation used. Could anyone help?
The formulation regarding this is the following (where Sy is the yield stress, E is the young modulus and xn is the hardening exponent) :
! Get yield stress from the specified hardening curve
Sf=Sy*(1.d0+E*eqplas/Sy)**xn
! Determine if active yielding
if (Smises.gt.(1.d0+toler)*Sf) then
! Calculate the flow direction
Sh=(stress(1)+stress(2)+stress(3))/3.d0
flow(1:3)=(stress(1:3)-Sh)/Smises
flow(4:ntens)=stress(4:ntens)/Smises
! Solve for Smises and deqpl using Newton's method
Et=E*xn*(1.d0+E*eqplas/Sy)**(xn-1)
do kewton=1,newton
rhs=Smises-(3.d0*eg)*deqpl-Sf
deqpl=deqpl+rhs/((3.d0*eg)+Et)
Sf=Sy*(1.d0+E*(eqplas+deqpl)/Sy)**xn
Et=E*xn*(1.d0+E*(eqplas+deqpl)/Sy)**(xn-1)
if(abs(rhs).lt.toler*Sy) exit
end do
if (kewton.eq.newton) write(7,*)'WARNING: plasticity loop failed'
I also upload the UMATHT file, in case someone needs it (public access)
I want to know if study habits and their effects on academic stress reduction are been studied and what are the main findings. I will appreciate any comments about this subject.
By stress vs displacement, I mean the stress that happened on the stirrups vs the displacement of the structure at a certain point.
I want to know what is the effect of smaller spacing of stirrups to the stress that occur in the stirrups.
Thank you
Can we study SiO2 and Si3N4 stress in Comsol? Can we study it simple Si/Sio2 /Si3N4 stack?
Couple stress fluid constitutive relation in vectorial form
I want to better understand how stress might increase blood pressure in rats. I can speculate that Wistar rats should be a better normotensive model than Wistar Kyoto rats.
An exercise psychology professional can help individuals enhance their performance, physical health, and enjoyment by helping them deal with physical, mental, and emotional stress. For example, following an injury, athletes may lack the motivation to perform due to poor outcomes and frustration.
Assume that there are some obstacles that impede dislocations movement in the matrix of a metal. Meanwhile, a unidirectional tensile test is carried out on this metal. Dislocations gradually pile up at the obstacle boundaries until critical stress is formed to break down the junctions and the obstacles.
Could you interpret how the work hardening will change before and after the breakdown?
I think first the work hardening experiences an increase and then it falls just after the breakdown.
For a research on a psychotherapeutic intervention for health care employees in the face of COVID-19 I am looking for the Nursing Stress Scale or a similar instrument to measure stress in nursing-staff. It would be great if anyone could help me.
Thank you :)
i want to know if what is the score if the person is having a moderate stress, loww, or high stress level
I am attempting to determine whether I can combine two different data sets. The first data set was collected from adult C57BL/6J mice at PND 160-PND 189 (5-6 months), and the second data set was collected from adult C57BL/6J mice at PND 115-PND 140 (3-4 months). I administered an acute restraint stress to both sets of mice, and am examining mRNA expression levels of stress neuropeptides and pro-inflammatory factors in the brain 24 hours after the stress exposure. Aside from the differences in ages, the experimental paradigm was kept identical for both cohorts of mice. The literature generally indicates that mice are considered "young adults" from about PND 90-PND 182 (3-6 months). However, one large scale analysis (Shoji 2016, Mol Brain) suggests that there are behavioral differences even between mice within this "young adulthood" age group (2-3 months, 4-5 months, and 6-7 months). I was wondering if anyone has come across differences in mRNA/protein expression levels across young adult mice of different ages, and whether you would recommend that I keep my two datasets separate based on this.
I am currently deriving the stress intensity factor for a crack at the edge of a circular hole in a plate. The integral form of the stress intensity factor is as follows:
I would like to inquire if there are any innovative approaches or potential combinations with emerging theoretical methods for solving this equation. Could you please provide some insights on this matter? Alternatively, are there any recommended reference books and papers on this topic?
Thank you for your time and attention.
I am trying to stress HEK293T cells but they seem very resistent.
Does anyone tried oxidative stress?
Which type of biodiversity is more resilient to change and how is a disturbance and stress different meaning in ecological dynamics?
Dear everyone, now I have got the principle strain tensor (or increment) of a material point, as well as the reference hardening curve of the material (along the rolling direction) together with the anisotropic yield stress ratios. I failed to calculate the corresponding equivalent stress. I know that if the material is isotropic, the situation is very simple because I can get the equivalent strain first (igoring the elastic strain), and then find the corresponding yield stress from the hardening curve. But what can I do under the Hill anisotropic plasticity? Can anybody help me with that? Thanks so much. p.s., for simplification, the elastic strain can be ignored.
I'm looking to develop my knowledge to get hired as a stress engineer for my first job onwards. It seems like reinventing the wheel sometimes to try and understand how the software works. Is it bad / waste of time to do that?
